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gerrit-public.fairphone.software / platform / external / llvm / 04c5be9f12fbb802ae48791399e999f29c0fb5c9 / . / 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>
38 <li><a href="#linkage_external">'<tt>externally visible</tt>' Linkage</a></li>
39 <li><a href="#linkage_dllimport">'<tt>dllimport</tt>' Linkage</a></li>
40 <li><a href="#linkage_dllexport">'<tt>dllexport</tt>' Linkage</a></li>
Bill Wendling3d10a5a2009-07-20 01:03:30 +0000[diff] [blame]41 </ol>
42 </li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]43 <li><a href="#callingconv">Calling Conventions</a></li>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]44 <li><a href="#namedtypes">Named Types</a></li>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]45 <li><a href="#globalvars">Global Variables</a></li>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]46 <li><a href="#functionstructure">Functions</a></li>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]47 <li><a href="#aliasstructure">Aliases</a></li>
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]48 <li><a href="#namedmetadatastructure">Named Metadata</a></li>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]49 <li><a href="#paramattrs">Parameter Attributes</a></li>
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]50 <li><a href="#fnattrs">Function Attributes</a></li>
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]51 <li><a href="#gc">Garbage Collector Names</a></li>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]52 <li><a href="#moduleasm">Module-Level Inline Assembly</a></li>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]53 <li><a href="#datalayout">Data Layout</a></li>
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]54 <li><a href="#pointeraliasing">Pointer Aliasing Rules</a></li>
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]55 <li><a href="#volatile">Volatile Memory Accesses</a></li>
Eli Friedman5b60e1b2011-07-20 21:35:53 +0000[diff] [blame]56 <li><a href="#memmodel">Memory Model for Concurrent Operations</a></li>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]57 <li><a href="#ordering">Atomic Memory Ordering Constraints</a></li>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]58 </ol>
59 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]60 <li><a href="#typesystem">Type System</a>
61 <ol>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]62 <li><a href="#t_classifications">Type Classifications</a></li>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]63 <li><a href="#t_primitive">Primitive Types</a>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]64 <ol>
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]65 <li><a href="#t_integer">Integer Type</a></li>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]66 <li><a href="#t_floating">Floating Point Types</a></li>
Dale Johannesen21fe99b2010-10-01 00:48:59 +0000[diff] [blame]67 <li><a href="#t_x86mmx">X86mmx Type</a></li>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]68 <li><a href="#t_void">Void Type</a></li>
69 <li><a href="#t_label">Label Type</a></li>
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]70 <li><a href="#t_metadata">Metadata Type</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]71 </ol>
72 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]73 <li><a href="#t_derived">Derived Types</a>
74 <ol>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]75 <li><a href="#t_aggregate">Aggregate Types</a>
76 <ol>
77 <li><a href="#t_array">Array Type</a></li>
78 <li><a href="#t_struct">Structure Type</a></li>
Chris Lattner628ed392011-07-23 19:59:08 +0000[diff] [blame]79 <li><a href="#t_opaque">Opaque Structure Types</a></li>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]80 <li><a href="#t_vector">Vector Type</a></li>
81 </ol>
82 </li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]83 <li><a href="#t_function">Function Type</a></li>
84 <li><a href="#t_pointer">Pointer Type</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]85 </ol>
86 </li>
87 </ol>
88 </li>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]89 <li><a href="#constants">Constants</a>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]90 <ol>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]91 <li><a href="#simpleconstants">Simple Constants</a></li>
Chris Lattner70882792009-02-28 18:32:25 +0000[diff] [blame]92 <li><a href="#complexconstants">Complex Constants</a></li>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]93 <li><a href="#globalconstants">Global Variable and Function Addresses</a></li>
94 <li><a href="#undefvalues">Undefined Values</a></li>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]95 <li><a href="#trapvalues">Trap Values</a></li>
Chris Lattnerf9d078e2009-10-27 21:19:13 +0000[diff] [blame]96 <li><a href="#blockaddress">Addresses of Basic Blocks</a></li>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]97 <li><a href="#constantexprs">Constant Expressions</a></li>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]98 </ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]99 </li>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]100 <li><a href="#othervalues">Other Values</a>
101 <ol>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]102 <li><a href="#inlineasm">Inline Assembler Expressions</a></li>
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]103 <li><a href="#metadata">Metadata Nodes and Metadata Strings</a></li>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]104 </ol>
105 </li>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]106 <li><a href="#intrinsic_globals">Intrinsic Global Variables</a>
107 <ol>
108 <li><a href="#intg_used">The '<tt>llvm.used</tt>' Global Variable</a></li>
Chris Lattner401e10c2009-07-20 06:14:25 +0000[diff] [blame]109 <li><a href="#intg_compiler_used">The '<tt>llvm.compiler.used</tt>'
110 Global Variable</a></li>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]111 <li><a href="#intg_global_ctors">The '<tt>llvm.global_ctors</tt>'
112 Global Variable</a></li>
113 <li><a href="#intg_global_dtors">The '<tt>llvm.global_dtors</tt>'
114 Global Variable</a></li>
115 </ol>
116 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]117 <li><a href="#instref">Instruction Reference</a>
118 <ol>
119 <li><a href="#terminators">Terminator Instructions</a>
120 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]121 <li><a href="#i_ret">'<tt>ret</tt>' Instruction</a></li>
122 <li><a href="#i_br">'<tt>br</tt>' Instruction</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]123 <li><a href="#i_switch">'<tt>switch</tt>' Instruction</a></li>
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]124 <li><a href="#i_indirectbr">'<tt>indirectbr</tt>' Instruction</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]125 <li><a href="#i_invoke">'<tt>invoke</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]126 <li><a href="#i_unwind">'<tt>unwind</tt>' Instruction</a></li>
Bill Wendlingdccc03b2011-07-31 06:30:59 +0000[diff] [blame]127 <li><a href="#i_resume">'<tt>resume</tt>' Instruction</a></li>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]128 <li><a href="#i_unreachable">'<tt>unreachable</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]129 </ol>
130 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]131 <li><a href="#binaryops">Binary Operations</a>
132 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]133 <li><a href="#i_add">'<tt>add</tt>' Instruction</a></li>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]134 <li><a href="#i_fadd">'<tt>fadd</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]135 <li><a href="#i_sub">'<tt>sub</tt>' Instruction</a></li>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]136 <li><a href="#i_fsub">'<tt>fsub</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]137 <li><a href="#i_mul">'<tt>mul</tt>' Instruction</a></li>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]138 <li><a href="#i_fmul">'<tt>fmul</tt>' Instruction</a></li>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]139 <li><a href="#i_udiv">'<tt>udiv</tt>' Instruction</a></li>
140 <li><a href="#i_sdiv">'<tt>sdiv</tt>' Instruction</a></li>
141 <li><a href="#i_fdiv">'<tt>fdiv</tt>' Instruction</a></li>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]142 <li><a href="#i_urem">'<tt>urem</tt>' Instruction</a></li>
143 <li><a href="#i_srem">'<tt>srem</tt>' Instruction</a></li>
144 <li><a href="#i_frem">'<tt>frem</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]145 </ol>
146 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]147 <li><a href="#bitwiseops">Bitwise Binary Operations</a>
148 <ol>
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]149 <li><a href="#i_shl">'<tt>shl</tt>' Instruction</a></li>
150 <li><a href="#i_lshr">'<tt>lshr</tt>' Instruction</a></li>
151 <li><a href="#i_ashr">'<tt>ashr</tt>' Instruction</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]152 <li><a href="#i_and">'<tt>and</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]153 <li><a href="#i_or">'<tt>or</tt>' Instruction</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]154 <li><a href="#i_xor">'<tt>xor</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]155 </ol>
156 </li>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]157 <li><a href="#vectorops">Vector Operations</a>
158 <ol>
159 <li><a href="#i_extractelement">'<tt>extractelement</tt>' Instruction</a></li>
160 <li><a href="#i_insertelement">'<tt>insertelement</tt>' Instruction</a></li>
161 <li><a href="#i_shufflevector">'<tt>shufflevector</tt>' Instruction</a></li>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]162 </ol>
163 </li>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]164 <li><a href="#aggregateops">Aggregate Operations</a>
165 <ol>
166 <li><a href="#i_extractvalue">'<tt>extractvalue</tt>' Instruction</a></li>
167 <li><a href="#i_insertvalue">'<tt>insertvalue</tt>' Instruction</a></li>
168 </ol>
169 </li>
Chris Lattner884a9702006-08-15 00:45:58 +0000[diff] [blame]170 <li><a href="#memoryops">Memory Access and Addressing Operations</a>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]171 <ol>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]172 <li><a href="#i_alloca">'<tt>alloca</tt>' Instruction</a></li>
173 <li><a href="#i_load">'<tt>load</tt>' Instruction</a></li>
174 <li><a href="#i_store">'<tt>store</tt>' Instruction</a></li>
175 <li><a href="#i_fence">'<tt>fence</tt>' Instruction</a></li>
176 <li><a href="#i_cmpxchg">'<tt>cmpxchg</tt>' Instruction</a></li>
177 <li><a href="#i_atomicrmw">'<tt>atomicrmw</tt>' Instruction</a></li>
Robert Bocchino7b81c752006-02-17 21:18:08 +0000[diff] [blame]178 <li><a href="#i_getelementptr">'<tt>getelementptr</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]179 </ol>
180 </li>
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]181 <li><a href="#convertops">Conversion Operations</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]182 <ol>
183 <li><a href="#i_trunc">'<tt>trunc .. to</tt>' Instruction</a></li>
184 <li><a href="#i_zext">'<tt>zext .. to</tt>' Instruction</a></li>
185 <li><a href="#i_sext">'<tt>sext .. to</tt>' Instruction</a></li>
186 <li><a href="#i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a></li>
187 <li><a href="#i_fpext">'<tt>fpext .. to</tt>' Instruction</a></li>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]188 <li><a href="#i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a></li>
189 <li><a href="#i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a></li>
190 <li><a href="#i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a></li>
191 <li><a href="#i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a></li>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]192 <li><a href="#i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a></li>
193 <li><a href="#i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a></li>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]194 <li><a href="#i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a></li>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]195 </ol>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]196 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]197 <li><a href="#otherops">Other Operations</a>
198 <ol>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]199 <li><a href="#i_icmp">'<tt>icmp</tt>' Instruction</a></li>
200 <li><a href="#i_fcmp">'<tt>fcmp</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]201 <li><a href="#i_phi">'<tt>phi</tt>' Instruction</a></li>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]202 <li><a href="#i_select">'<tt>select</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]203 <li><a href="#i_call">'<tt>call</tt>' Instruction</a></li>
Chris Lattnerfb6977d2006-01-13 23:26:01 +0000[diff] [blame]204 <li><a href="#i_va_arg">'<tt>va_arg</tt>' Instruction</a></li>
Bill Wendlingf78faf82011-08-02 21:52:38 +0000[diff] [blame]205 <li><a href="#i_landingpad">'<tt>landingpad</tt>' Instruction</a></li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]206 </ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]207 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]208 </ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]209 </li>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]210 <li><a href="#intrinsics">Intrinsic Functions</a>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]211 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]212 <li><a href="#int_varargs">Variable Argument Handling Intrinsics</a>
213 <ol>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]214 <li><a href="#int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a></li>
215 <li><a href="#int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a></li>
216 <li><a href="#int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]217 </ol>
218 </li>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]219 <li><a href="#int_gc">Accurate Garbage Collection Intrinsics</a>
220 <ol>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]221 <li><a href="#int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a></li>
222 <li><a href="#int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a></li>
223 <li><a href="#int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a></li>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]224 </ol>
225 </li>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]226 <li><a href="#int_codegen">Code Generator Intrinsics</a>
227 <ol>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]228 <li><a href="#int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a></li>
229 <li><a href="#int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a></li>
230 <li><a href="#int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a></li>
231 <li><a href="#int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a></li>
232 <li><a href="#int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a></li>
233 <li><a href="#int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a></li>
Dan Gohman31f1af12010-05-26 21:56:15 +0000[diff] [blame]234 <li><a href="#int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a></li>
John Criswell7123e272004-04-09 16:43:20 +0000[diff] [blame]235 </ol>
236 </li>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]237 <li><a href="#int_libc">Standard C Library Intrinsics</a>
238 <ol>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]239 <li><a href="#int_memcpy">'<tt>llvm.memcpy.*</tt>' Intrinsic</a></li>
240 <li><a href="#int_memmove">'<tt>llvm.memmove.*</tt>' Intrinsic</a></li>
241 <li><a href="#int_memset">'<tt>llvm.memset.*</tt>' Intrinsic</a></li>
242 <li><a href="#int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a></li>
243 <li><a href="#int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a></li>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]244 <li><a href="#int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a></li>
245 <li><a href="#int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a></li>
246 <li><a href="#int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a></li>
Dan Gohman08b280b2011-05-27 00:36:31 +0000[diff] [blame]247 <li><a href="#int_exp">'<tt>llvm.exp.*</tt>' Intrinsic</a></li>
248 <li><a href="#int_log">'<tt>llvm.log.*</tt>' Intrinsic</a></li>
Cameron Zwarich33390842011-07-08 21:39:21 +0000[diff] [blame]249 <li><a href="#int_fma">'<tt>llvm.fma.*</tt>' Intrinsic</a></li>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]250 </ol>
251 </li>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]252 <li><a href="#int_manip">Bit Manipulation Intrinsics</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]253 <ol>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]254 <li><a href="#int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a></li>
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]255 <li><a href="#int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic </a></li>
256 <li><a href="#int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic </a></li>
257 <li><a href="#int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic </a></li>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]258 </ol>
259 </li>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]260 <li><a href="#int_overflow">Arithmetic with Overflow Intrinsics</a>
261 <ol>
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]262 <li><a href="#int_sadd_overflow">'<tt>llvm.sadd.with.overflow.*</tt> Intrinsics</a></li>
263 <li><a href="#int_uadd_overflow">'<tt>llvm.uadd.with.overflow.*</tt> Intrinsics</a></li>
264 <li><a href="#int_ssub_overflow">'<tt>llvm.ssub.with.overflow.*</tt> Intrinsics</a></li>
265 <li><a href="#int_usub_overflow">'<tt>llvm.usub.with.overflow.*</tt> Intrinsics</a></li>
266 <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]267 <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]268 </ol>
269 </li>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]270 <li><a href="#int_fp16">Half Precision Floating Point Intrinsics</a>
271 <ol>
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]272 <li><a href="#int_convert_to_fp16">'<tt>llvm.convert.to.fp16</tt>' Intrinsic</a></li>
273 <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]274 </ol>
275 </li>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]276 <li><a href="#int_debugger">Debugger intrinsics</a></li>
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]277 <li><a href="#int_eh">Exception Handling intrinsics</a></li>
Duncan Sands4a544a72011-09-06 13:37:06 +0000[diff] [blame]278 <li><a href="#int_trampoline">Trampoline Intrinsics</a>
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]279 <ol>
280 <li><a href="#int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a></li>
Duncan Sands4a544a72011-09-06 13:37:06 +0000[diff] [blame]281 <li><a href="#int_at">'<tt>llvm.adjust.trampoline</tt>' Intrinsic</a></li>
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]282 </ol>
283 </li>
Bill Wendling3c44f5b2008-11-18 22:10:53 +0000[diff] [blame]284 <li><a href="#int_atomics">Atomic intrinsics</a>
285 <ol>
286 <li><a href="#int_memory_barrier"><tt>llvm.memory_barrier</tt></a></li>
287 <li><a href="#int_atomic_cmp_swap"><tt>llvm.atomic.cmp.swap</tt></a></li>
288 <li><a href="#int_atomic_swap"><tt>llvm.atomic.swap</tt></a></li>
289 <li><a href="#int_atomic_load_add"><tt>llvm.atomic.load.add</tt></a></li>
290 <li><a href="#int_atomic_load_sub"><tt>llvm.atomic.load.sub</tt></a></li>
291 <li><a href="#int_atomic_load_and"><tt>llvm.atomic.load.and</tt></a></li>
292 <li><a href="#int_atomic_load_nand"><tt>llvm.atomic.load.nand</tt></a></li>
293 <li><a href="#int_atomic_load_or"><tt>llvm.atomic.load.or</tt></a></li>
294 <li><a href="#int_atomic_load_xor"><tt>llvm.atomic.load.xor</tt></a></li>
295 <li><a href="#int_atomic_load_max"><tt>llvm.atomic.load.max</tt></a></li>
296 <li><a href="#int_atomic_load_min"><tt>llvm.atomic.load.min</tt></a></li>
297 <li><a href="#int_atomic_load_umax"><tt>llvm.atomic.load.umax</tt></a></li>
298 <li><a href="#int_atomic_load_umin"><tt>llvm.atomic.load.umin</tt></a></li>
299 </ol>
300 </li>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]301 <li><a href="#int_memorymarkers">Memory Use Markers</a>
302 <ol>
303 <li><a href="#int_lifetime_start"><tt>llvm.lifetime.start</tt></a></li>
304 <li><a href="#int_lifetime_end"><tt>llvm.lifetime.end</tt></a></li>
305 <li><a href="#int_invariant_start"><tt>llvm.invariant.start</tt></a></li>
306 <li><a href="#int_invariant_end"><tt>llvm.invariant.end</tt></a></li>
307 </ol>
308 </li>
Reid Spencer20677642007-07-20 19:59:11 +0000[diff] [blame]309 <li><a href="#int_general">General intrinsics</a>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]310 <ol>
Reid Spencer20677642007-07-20 19:59:11 +0000[diff] [blame]311 <li><a href="#int_var_annotation">
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]312 '<tt>llvm.var.annotation</tt>' Intrinsic</a></li>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]313 <li><a href="#int_annotation">
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]314 '<tt>llvm.annotation.*</tt>' Intrinsic</a></li>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]315 <li><a href="#int_trap">
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]316 '<tt>llvm.trap</tt>' Intrinsic</a></li>
317 <li><a href="#int_stackprotector">
318 '<tt>llvm.stackprotector</tt>' Intrinsic</a></li>
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]319 <li><a href="#int_objectsize">
320 '<tt>llvm.objectsize</tt>' Intrinsic</a></li>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]321 </ol>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]322 </li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]323 </ol>
324 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]325</ol>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]326
327<div class="doc_author">
328 <p>Written by <a href="mailto:sabre@nondot.org">Chris Lattner</a>
329 and <a href="mailto:vadve@cs.uiuc.edu">Vikram Adve</a></p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]330</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]331
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]332<!-- *********************************************************************** -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]333<h2><a name="abstract">Abstract</a></h2>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]334<!-- *********************************************************************** -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]335
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]336<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]337
338<p>This document is a reference manual for the LLVM assembly language. LLVM is
339 a Static Single Assignment (SSA) based representation that provides type
340 safety, low-level operations, flexibility, and the capability of representing
341 'all' high-level languages cleanly. It is the common code representation
342 used throughout all phases of the LLVM compilation strategy.</p>
343
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]344</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]345
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]346<!-- *********************************************************************** -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]347<h2><a name="introduction">Introduction</a></h2>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]348<!-- *********************************************************************** -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]349
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]350<div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]351
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]352<p>The LLVM code representation is designed to be used in three different forms:
353 as an in-memory compiler IR, as an on-disk bitcode representation (suitable
354 for fast loading by a Just-In-Time compiler), and as a human readable
355 assembly language representation. This allows LLVM to provide a powerful
356 intermediate representation for efficient compiler transformations and
357 analysis, while providing a natural means to debug and visualize the
358 transformations. The three different forms of LLVM are all equivalent. This
359 document describes the human readable representation and notation.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]360
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]361<p>The LLVM representation aims to be light-weight and low-level while being
362 expressive, typed, and extensible at the same time. It aims to be a
363 "universal IR" of sorts, by being at a low enough level that high-level ideas
364 may be cleanly mapped to it (similar to how microprocessors are "universal
365 IR's", allowing many source languages to be mapped to them). By providing
366 type information, LLVM can be used as the target of optimizations: for
367 example, through pointer analysis, it can be proven that a C automatic
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]368 variable is never accessed outside of the current function, allowing it to
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]369 be promoted to a simple SSA value instead of a memory location.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]370
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]371<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]372<h4>
373 <a name="wellformed">Well-Formedness</a>
374</h4>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]375
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]376<div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]377
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]378<p>It is important to note that this document describes 'well formed' LLVM
379 assembly language. There is a difference between what the parser accepts and
380 what is considered 'well formed'. For example, the following instruction is
381 syntactically okay, but not well formed:</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]382
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]383<pre class="doc_code">
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]384%x = <a href="#i_add">add</a> i32 1, %x
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]385</pre>
386
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]387<p>because the definition of <tt>%x</tt> does not dominate all of its uses. The
388 LLVM infrastructure provides a verification pass that may be used to verify
389 that an LLVM module is well formed. This pass is automatically run by the
390 parser after parsing input assembly and by the optimizer before it outputs
391 bitcode. The violations pointed out by the verifier pass indicate bugs in
392 transformation passes or input to the parser.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]393
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]394</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]395
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]396</div>
397
Chris Lattnercc689392007-10-03 17:34:29 +0000[diff] [blame]398<!-- Describe the typesetting conventions here. -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]399
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]400<!-- *********************************************************************** -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]401<h2><a name="identifiers">Identifiers</a></h2>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]402<!-- *********************************************************************** -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]403
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]404<div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]405
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]406<p>LLVM identifiers come in two basic types: global and local. Global
407 identifiers (functions, global variables) begin with the <tt>'@'</tt>
408 character. Local identifiers (register names, types) begin with
409 the <tt>'%'</tt> character. Additionally, there are three different formats
410 for identifiers, for different purposes:</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]411
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]412<ol>
Reid Spencer2c452282007-08-07 14:34:28 +0000[diff] [blame]413 <li>Named values are represented as a string of characters with their prefix.
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]414 For example, <tt>%foo</tt>, <tt>@DivisionByZero</tt>,
415 <tt>%a.really.long.identifier</tt>. The actual regular expression used is
416 '<tt>[%@][a-zA-Z$._][a-zA-Z$._0-9]*</tt>'. Identifiers which require
417 other characters in their names can be surrounded with quotes. Special
418 characters may be escaped using <tt>"\xx"</tt> where <tt>xx</tt> is the
419 ASCII code for the character in hexadecimal. In this way, any character
420 can be used in a name value, even quotes themselves.</li>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]421
Reid Spencer2c452282007-08-07 14:34:28 +0000[diff] [blame]422 <li>Unnamed values are represented as an unsigned numeric value with their
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]423 prefix. For example, <tt>%12</tt>, <tt>@2</tt>, <tt>%44</tt>.</li>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]424
Reid Spencercc16dc32004-12-09 18:02:53 +0000[diff] [blame]425 <li>Constants, which are described in a <a href="#constants">section about
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]426 constants</a>, below.</li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]427</ol>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]428
Reid Spencer2c452282007-08-07 14:34:28 +0000[diff] [blame]429<p>LLVM requires that values start with a prefix for two reasons: Compilers
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]430 don't need to worry about name clashes with reserved words, and the set of
431 reserved words may be expanded in the future without penalty. Additionally,
432 unnamed identifiers allow a compiler to quickly come up with a temporary
433 variable without having to avoid symbol table conflicts.</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]434
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]435<p>Reserved words in LLVM are very similar to reserved words in other
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]436 languages. There are keywords for different opcodes
437 ('<tt><a href="#i_add">add</a></tt>',
438 '<tt><a href="#i_bitcast">bitcast</a></tt>',
439 '<tt><a href="#i_ret">ret</a></tt>', etc...), for primitive type names
440 ('<tt><a href="#t_void">void</a></tt>',
441 '<tt><a href="#t_primitive">i32</a></tt>', etc...), and others. These
442 reserved words cannot conflict with variable names, because none of them
443 start with a prefix character (<tt>'%'</tt> or <tt>'@'</tt>).</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]444
445<p>Here is an example of LLVM code to multiply the integer variable
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]446 '<tt>%X</tt>' by 8:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]447
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]448<p>The easy way:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]449
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]450<pre class="doc_code">
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]451%result = <a href="#i_mul">mul</a> i32 %X, 8
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]452</pre>
453
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]454<p>After strength reduction:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]455
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]456<pre class="doc_code">
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]457%result = <a href="#i_shl">shl</a> i32 %X, i8 3
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]458</pre>
459
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]460<p>And the hard way:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]461
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]462<pre class="doc_code">
Gabor Greifec58f752009-10-28 13:05:07 +0000[diff] [blame]463%0 = <a href="#i_add">add</a> i32 %X, %X <i>; yields {i32}:%0</i>
464%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]465%result = <a href="#i_add">add</a> i32 %1, %1
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]466</pre>
467
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]468<p>This last way of multiplying <tt>%X</tt> by 8 illustrates several important
469 lexical features of LLVM:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]470
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]471<ol>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]472 <li>Comments are delimited with a '<tt>;</tt>' and go until the end of
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]473 line.</li>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]474
475 <li>Unnamed temporaries are created when the result of a computation is not
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]476 assigned to a named value.</li>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]477
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]478 <li>Unnamed temporaries are numbered sequentially</li>
479</ol>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]480
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]481<p>It also shows a convention that we follow in this document. When
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]482 demonstrating instructions, we will follow an instruction with a comment that
483 defines the type and name of value produced. Comments are shown in italic
484 text.</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]485
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]486</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]487
488<!-- *********************************************************************** -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]489<h2><a name="highlevel">High Level Structure</a></h2>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]490<!-- *********************************************************************** -->
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]491<div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]492<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]493<h3>
494 <a name="modulestructure">Module Structure</a>
495</h3>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]496
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]497<div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]498
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]499<p>LLVM programs are composed of "Module"s, each of which is a translation unit
500 of the input programs. Each module consists of functions, global variables,
501 and symbol table entries. Modules may be combined together with the LLVM
502 linker, which merges function (and global variable) definitions, resolves
503 forward declarations, and merges symbol table entries. Here is an example of
504 the "hello world" module:</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]505
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]506<pre class="doc_code">
Chris Lattner63e4ccb2010-08-17 17:13:42 +0000[diff] [blame]507<i>; Declare the string constant as a global constant.</i>&nbsp;
Nick Lewyckydb9cd762011-01-29 01:09:53 +0000[diff] [blame]508<a href="#identifiers">@.LC0</a> = <a href="#linkage_internal">internal</a>&nbsp;<a href="#globalvars">constant</a>&nbsp;<a href="#t_array">[13 x i8]</a> c"hello world\0A\00" <i>; [13 x i8]*</i>&nbsp;
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]509
Chris Lattner63e4ccb2010-08-17 17:13:42 +0000[diff] [blame]510<i>; External declaration of the puts function</i>&nbsp;
511<a href="#functionstructure">declare</a> i32 @puts(i8*) <i>; i32 (i8*)* </i>&nbsp;
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]512
513<i>; Definition of main function</i>
Chris Lattner63e4ccb2010-08-17 17:13:42 +0000[diff] [blame]514define i32 @main() { <i>; i32()* </i>&nbsp;
515 <i>; Convert [13 x i8]* to i8 *...</i>&nbsp;
516 %cast210 = <a href="#i_getelementptr">getelementptr</a> [13 x i8]* @.LC0, i64 0, i64 0 <i>; i8*</i>&nbsp;
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]517
Chris Lattner63e4ccb2010-08-17 17:13:42 +0000[diff] [blame]518 <i>; Call puts function to write out the string to stdout.</i>&nbsp;
519 <a href="#i_call">call</a> i32 @puts(i8* %cast210) <i>; i32</i>&nbsp;
520 <a href="#i_ret">ret</a> i32 0&nbsp;
521}
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]522
523<i>; Named metadata</i>
524!1 = metadata !{i32 41}
525!foo = !{!1, null}
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]526</pre>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]527
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]528<p>This example is made up of a <a href="#globalvars">global variable</a> named
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]529 "<tt>.LC0</tt>", an external declaration of the "<tt>puts</tt>" function,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]530 a <a href="#functionstructure">function definition</a> for
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]531 "<tt>main</tt>" and <a href="#namedmetadatastructure">named metadata</a>
532 "<tt>foo"</tt>.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]533
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]534<p>In general, a module is made up of a list of global values, where both
535 functions and global variables are global values. Global values are
536 represented by a pointer to a memory location (in this case, a pointer to an
537 array of char, and a pointer to a function), and have one of the
538 following <a href="#linkage">linkage types</a>.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]539
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]540</div>
541
542<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]543<h3>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]544 <a name="linkage">Linkage Types</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]545</h3>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]546
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]547<div>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]548
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]549<p>All Global Variables and Functions have one of the following types of
550 linkage:</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]551
552<dl>
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]553 <dt><tt><b><a name="linkage_private">private</a></b></tt></dt>
Bill Wendling5e721d72010-07-01 21:55:59 +0000[diff] [blame]554 <dd>Global values with "<tt>private</tt>" linkage are only directly accessible
555 by objects in the current module. In particular, linking code into a
556 module with an private global value may cause the private to be renamed as
557 necessary to avoid collisions. Because the symbol is private to the
558 module, all references can be updated. This doesn't show up in any symbol
559 table in the object file.</dd>
Rafael Espindolabb46f522009-01-15 20:18:42 +0000[diff] [blame]560
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]561 <dt><tt><b><a name="linkage_linker_private">linker_private</a></b></tt></dt>
Bill Wendling5e721d72010-07-01 21:55:59 +0000[diff] [blame]562 <dd>Similar to <tt>private</tt>, but the symbol is passed through the
563 assembler and evaluated by the linker. Unlike normal strong symbols, they
564 are removed by the linker from the final linked image (executable or
565 dynamic library).</dd>
566
567 <dt><tt><b><a name="linkage_linker_private_weak">linker_private_weak</a></b></tt></dt>
568 <dd>Similar to "<tt>linker_private</tt>", but the symbol is weak. Note that
569 <tt>linker_private_weak</tt> symbols are subject to coalescing by the
570 linker. The symbols are removed by the linker from the final linked image
571 (executable or dynamic library).</dd>
Bill Wendling3d10a5a2009-07-20 01:03:30 +0000[diff] [blame]572
Bill Wendling55ae5152010-08-20 22:05:50 +0000[diff] [blame]573 <dt><tt><b><a name="linkage_linker_private_weak_def_auto">linker_private_weak_def_auto</a></b></tt></dt>
574 <dd>Similar to "<tt>linker_private_weak</tt>", but it's known that the address
575 of the object is not taken. For instance, functions that had an inline
576 definition, but the compiler decided not to inline it. Note,
577 unlike <tt>linker_private</tt> and <tt>linker_private_weak</tt>,
578 <tt>linker_private_weak_def_auto</tt> may have only <tt>default</tt>
579 visibility. The symbols are removed by the linker from the final linked
580 image (executable or dynamic library).</dd>
581
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]582 <dt><tt><b><a name="linkage_internal">internal</a></b></tt></dt>
Bill Wendling07d31772010-06-29 22:34:52 +0000[diff] [blame]583 <dd>Similar to private, but the value shows as a local symbol
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]584 (<tt>STB_LOCAL</tt> in the case of ELF) in the object file. This
585 corresponds to the notion of the '<tt>static</tt>' keyword in C.</dd>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]586
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]587 <dt><tt><b><a name="linkage_available_externally">available_externally</a></b></tt></dt>
Chris Lattner266c7bb2009-04-13 05:44:34 +0000[diff] [blame]588 <dd>Globals with "<tt>available_externally</tt>" linkage are never emitted
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]589 into the object file corresponding to the LLVM module. They exist to
590 allow inlining and other optimizations to take place given knowledge of
591 the definition of the global, which is known to be somewhere outside the
592 module. Globals with <tt>available_externally</tt> linkage are allowed to
593 be discarded at will, and are otherwise the same as <tt>linkonce_odr</tt>.
594 This linkage type is only allowed on definitions, not declarations.</dd>
Chris Lattner266c7bb2009-04-13 05:44:34 +0000[diff] [blame]595
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]596 <dt><tt><b><a name="linkage_linkonce">linkonce</a></b></tt></dt>
Chris Lattner4887bd82007-01-14 06:51:48 +0000[diff] [blame]597 <dd>Globals with "<tt>linkonce</tt>" linkage are merged with other globals of
Chris Lattner873187c2010-01-09 19:15:14 +0000[diff] [blame]598 the same name when linkage occurs. This can be used to implement
599 some forms of inline functions, templates, or other code which must be
600 generated in each translation unit that uses it, but where the body may
601 be overridden with a more definitive definition later. Unreferenced
602 <tt>linkonce</tt> globals are allowed to be discarded. Note that
603 <tt>linkonce</tt> linkage does not actually allow the optimizer to
604 inline the body of this function into callers because it doesn't know if
605 this definition of the function is the definitive definition within the
606 program or whether it will be overridden by a stronger definition.
607 To enable inlining and other optimizations, use "<tt>linkonce_odr</tt>"
608 linkage.</dd>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]609
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]610 <dt><tt><b><a name="linkage_weak">weak</a></b></tt></dt>
Chris Lattner26d054d2009-08-05 05:21:07 +0000[diff] [blame]611 <dd>"<tt>weak</tt>" linkage has the same merging semantics as
612 <tt>linkonce</tt> linkage, except that unreferenced globals with
613 <tt>weak</tt> linkage may not be discarded. This is used for globals that
614 are declared "weak" in C source code.</dd>
615
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]616 <dt><tt><b><a name="linkage_common">common</a></b></tt></dt>
Chris Lattner26d054d2009-08-05 05:21:07 +0000[diff] [blame]617 <dd>"<tt>common</tt>" linkage is most similar to "<tt>weak</tt>" linkage, but
618 they are used for tentative definitions in C, such as "<tt>int X;</tt>" at
619 global scope.
620 Symbols with "<tt>common</tt>" linkage are merged in the same way as
621 <tt>weak symbols</tt>, and they may not be deleted if unreferenced.
Chris Lattnercd81f5d2009-08-05 05:41:44 +0000[diff] [blame]622 <tt>common</tt> symbols may not have an explicit section,
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]623 must have a zero initializer, and may not be marked '<a
Chris Lattnercd81f5d2009-08-05 05:41:44 +0000[diff] [blame]624 href="#globalvars"><tt>constant</tt></a>'. Functions and aliases may not
625 have common linkage.</dd>
Chris Lattner26d054d2009-08-05 05:21:07 +0000[diff] [blame]626
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]627
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]628 <dt><tt><b><a name="linkage_appending">appending</a></b></tt></dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]629 <dd>"<tt>appending</tt>" linkage may only be applied to global variables of
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]630 pointer to array type. When two global variables with appending linkage
631 are linked together, the two global arrays are appended together. This is
632 the LLVM, typesafe, equivalent of having the system linker append together
633 "sections" with identical names when .o files are linked.</dd>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]634
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]635 <dt><tt><b><a name="linkage_externweak">extern_weak</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]636 <dd>The semantics of this linkage follow the ELF object file model: the symbol
637 is weak until linked, if not linked, the symbol becomes null instead of
638 being an undefined reference.</dd>
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]639
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]640 <dt><tt><b><a name="linkage_linkonce_odr">linkonce_odr</a></b></tt></dt>
641 <dt><tt><b><a name="linkage_weak_odr">weak_odr</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]642 <dd>Some languages allow differing globals to be merged, such as two functions
643 with different semantics. Other languages, such as <tt>C++</tt>, ensure
Bill Wendling5e721d72010-07-01 21:55:59 +0000[diff] [blame]644 that only equivalent globals are ever merged (the "one definition rule"
645 &mdash; "ODR"). Such languages can use the <tt>linkonce_odr</tt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]646 and <tt>weak_odr</tt> linkage types to indicate that the global will only
647 be merged with equivalent globals. These linkage types are otherwise the
648 same as their non-<tt>odr</tt> versions.</dd>
Duncan Sands667d4b82009-03-07 15:45:40 +0000[diff] [blame]649
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]650 <dt><tt><b><a name="linkage_external">externally visible</a></b></tt>:</dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]651 <dd>If none of the above identifiers are used, the global is externally
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]652 visible, meaning that it participates in linkage and can be used to
653 resolve external symbol references.</dd>
Reid Spencerc8910842007-04-11 23:49:50 +0000[diff] [blame]654</dl>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]655
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]656<p>The next two types of linkage are targeted for Microsoft Windows platform
657 only. They are designed to support importing (exporting) symbols from (to)
658 DLLs (Dynamic Link Libraries).</p>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]659
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]660<dl>
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]661 <dt><tt><b><a name="linkage_dllimport">dllimport</a></b></tt></dt>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]662 <dd>"<tt>dllimport</tt>" linkage causes the compiler to reference a function
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]663 or variable via a global pointer to a pointer that is set up by the DLL
664 exporting the symbol. On Microsoft Windows targets, the pointer name is
665 formed by combining <code>__imp_</code> and the function or variable
666 name.</dd>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]667
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]668 <dt><tt><b><a name="linkage_dllexport">dllexport</a></b></tt></dt>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]669 <dd>"<tt>dllexport</tt>" linkage causes the compiler to provide a global
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]670 pointer to a pointer in a DLL, so that it can be referenced with the
671 <tt>dllimport</tt> attribute. On Microsoft Windows targets, the pointer
672 name is formed by combining <code>__imp_</code> and the function or
673 variable name.</dd>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]674</dl>
675
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]676<p>For example, since the "<tt>.LC0</tt>" variable is defined to be internal, if
677 another module defined a "<tt>.LC0</tt>" variable and was linked with this
678 one, one of the two would be renamed, preventing a collision. Since
679 "<tt>main</tt>" and "<tt>puts</tt>" are external (i.e., lacking any linkage
680 declarations), they are accessible outside of the current module.</p>
681
682<p>It is illegal for a function <i>declaration</i> to have any linkage type
683 other than "externally visible", <tt>dllimport</tt>
684 or <tt>extern_weak</tt>.</p>
685
Duncan Sands667d4b82009-03-07 15:45:40 +0000[diff] [blame]686<p>Aliases can have only <tt>external</tt>, <tt>internal</tt>, <tt>weak</tt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]687 or <tt>weak_odr</tt> linkages.</p>
688
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]689</div>
690
691<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]692<h3>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]693 <a name="callingconv">Calling Conventions</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]694</h3>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]695
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]696<div>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]697
698<p>LLVM <a href="#functionstructure">functions</a>, <a href="#i_call">calls</a>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]699 and <a href="#i_invoke">invokes</a> can all have an optional calling
700 convention specified for the call. The calling convention of any pair of
701 dynamic caller/callee must match, or the behavior of the program is
702 undefined. The following calling conventions are supported by LLVM, and more
703 may be added in the future:</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]704
705<dl>
706 <dt><b>"<tt>ccc</tt>" - The C calling convention</b>:</dt>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]707 <dd>This calling convention (the default if no other calling convention is
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]708 specified) matches the target C calling conventions. This calling
709 convention supports varargs function calls and tolerates some mismatch in
710 the declared prototype and implemented declaration of the function (as
711 does normal C).</dd>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]712
713 <dt><b>"<tt>fastcc</tt>" - The fast calling convention</b>:</dt>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]714 <dd>This calling convention attempts to make calls as fast as possible
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]715 (e.g. by passing things in registers). This calling convention allows the
716 target to use whatever tricks it wants to produce fast code for the
717 target, without having to conform to an externally specified ABI
Jeffrey Yasskin95fa80a2010-01-09 19:44:16 +0000[diff] [blame]718 (Application Binary Interface).
719 <a href="CodeGenerator.html#tailcallopt">Tail calls can only be optimized
Chris Lattner29689432010-03-11 00:22:57 +0000[diff] [blame]720 when this or the GHC convention is used.</a> This calling convention
721 does not support varargs and requires the prototype of all callees to
722 exactly match the prototype of the function definition.</dd>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]723
724 <dt><b>"<tt>coldcc</tt>" - The cold calling convention</b>:</dt>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]725 <dd>This calling convention attempts to make code in the caller as efficient
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]726 as possible under the assumption that the call is not commonly executed.
727 As such, these calls often preserve all registers so that the call does
728 not break any live ranges in the caller side. This calling convention
729 does not support varargs and requires the prototype of all callees to
730 exactly match the prototype of the function definition.</dd>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]731
Chris Lattner29689432010-03-11 00:22:57 +0000[diff] [blame]732 <dt><b>"<tt>cc <em>10</em></tt>" - GHC convention</b>:</dt>
733 <dd>This calling convention has been implemented specifically for use by the
734 <a href="http://www.haskell.org/ghc">Glasgow Haskell Compiler (GHC)</a>.
735 It passes everything in registers, going to extremes to achieve this by
736 disabling callee save registers. This calling convention should not be
737 used lightly but only for specific situations such as an alternative to
738 the <em>register pinning</em> performance technique often used when
739 implementing functional programming languages.At the moment only X86
740 supports this convention and it has the following limitations:
741 <ul>
742 <li>On <em>X86-32</em> only supports up to 4 bit type parameters. No
743 floating point types are supported.</li>
744 <li>On <em>X86-64</em> only supports up to 10 bit type parameters and
745 6 floating point parameters.</li>
746 </ul>
747 This calling convention supports
748 <a href="CodeGenerator.html#tailcallopt">tail call optimization</a> but
749 requires both the caller and callee are using it.
750 </dd>
751
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame]752 <dt><b>"<tt>cc &lt;<em>n</em>&gt;</tt>" - Numbered convention</b>:</dt>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]753 <dd>Any calling convention may be specified by number, allowing
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]754 target-specific calling conventions to be used. Target specific calling
755 conventions start at 64.</dd>
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame]756</dl>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]757
758<p>More calling conventions can be added/defined on an as-needed basis, to
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]759 support Pascal conventions or any other well-known target-independent
760 convention.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]761
762</div>
763
764<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]765<h3>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]766 <a name="visibility">Visibility Styles</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]767</h3>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]768
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]769<div>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]770
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]771<p>All Global Variables and Functions have one of the following visibility
772 styles:</p>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]773
774<dl>
775 <dt><b>"<tt>default</tt>" - Default style</b>:</dt>
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]776 <dd>On targets that use the ELF object file format, default visibility means
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]777 that the declaration is visible to other modules and, in shared libraries,
778 means that the declared entity may be overridden. On Darwin, default
779 visibility means that the declaration is visible to other modules. Default
780 visibility corresponds to "external linkage" in the language.</dd>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]781
782 <dt><b>"<tt>hidden</tt>" - Hidden style</b>:</dt>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]783 <dd>Two declarations of an object with hidden visibility refer to the same
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]784 object if they are in the same shared object. Usually, hidden visibility
785 indicates that the symbol will not be placed into the dynamic symbol
786 table, so no other module (executable or shared library) can reference it
787 directly.</dd>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]788
Anton Korobeynikov6f9896f2007-04-29 18:35:00 +0000[diff] [blame]789 <dt><b>"<tt>protected</tt>" - Protected style</b>:</dt>
Anton Korobeynikov6f9896f2007-04-29 18:35:00 +0000[diff] [blame]790 <dd>On ELF, protected visibility indicates that the symbol will be placed in
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]791 the dynamic symbol table, but that references within the defining module
792 will bind to the local symbol. That is, the symbol cannot be overridden by
793 another module.</dd>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]794</dl>
795
796</div>
797
798<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]799<h3>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]800 <a name="namedtypes">Named Types</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]801</h3>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]802
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]803<div>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]804
805<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]806 it easier to read the IR and make the IR more condensed (particularly when
807 recursive types are involved). An example of a name specification is:</p>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]808
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]809<pre class="doc_code">
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]810%mytype = type { %mytype*, i32 }
811</pre>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]812
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]813<p>You may give a name to any <a href="#typesystem">type</a> except
Chris Lattnerdc65f222010-08-17 23:26:04 +0000[diff] [blame]814 "<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]815 is expected with the syntax "%mytype".</p>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]816
817<p>Note that type names are aliases for the structural type that they indicate,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]818 and that you can therefore specify multiple names for the same type. This
819 often leads to confusing behavior when dumping out a .ll file. Since LLVM IR
820 uses structural typing, the name is not part of the type. When printing out
821 LLVM IR, the printer will pick <em>one name</em> to render all types of a
822 particular shape. This means that if you have code where two different
823 source types end up having the same LLVM type, that the dumper will sometimes
824 print the "wrong" or unexpected type. This is an important design point and
825 isn't going to change.</p>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]826
827</div>
828
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]829<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]830<h3>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]831 <a name="globalvars">Global Variables</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]832</h3>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]833
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]834<div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]835
Chris Lattner3689a342005-02-12 19:30:21 +0000[diff] [blame]836<p>Global variables define regions of memory allocated at compilation time
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]837 instead of run-time. Global variables may optionally be initialized, may
838 have an explicit section to be placed in, and may have an optional explicit
839 alignment specified. A variable may be defined as "thread_local", which
840 means that it will not be shared by threads (each thread will have a
841 separated copy of the variable). A variable may be defined as a global
842 "constant," which indicates that the contents of the variable
843 will <b>never</b> be modified (enabling better optimization, allowing the
844 global data to be placed in the read-only section of an executable, etc).
845 Note that variables that need runtime initialization cannot be marked
846 "constant" as there is a store to the variable.</p>
Chris Lattner3689a342005-02-12 19:30:21 +0000[diff] [blame]847
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]848<p>LLVM explicitly allows <em>declarations</em> of global variables to be marked
849 constant, even if the final definition of the global is not. This capability
850 can be used to enable slightly better optimization of the program, but
851 requires the language definition to guarantee that optimizations based on the
852 'constantness' are valid for the translation units that do not include the
853 definition.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]854
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]855<p>As SSA values, global variables define pointer values that are in scope
856 (i.e. they dominate) all basic blocks in the program. Global variables
857 always define a pointer to their "content" type because they describe a
858 region of memory, and all memory objects in LLVM are accessed through
859 pointers.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]860
Rafael Espindolabea46262011-01-08 16:42:36 +0000[diff] [blame]861<p>Global variables can be marked with <tt>unnamed_addr</tt> which indicates
862 that the address is not significant, only the content. Constants marked
Rafael Espindolaa5eaa862011-01-15 08:20:57 +0000[diff] [blame]863 like this can be merged with other constants if they have the same
864 initializer. Note that a constant with significant address <em>can</em>
865 be merged with a <tt>unnamed_addr</tt> constant, the result being a
866 constant whose address is significant.</p>
Rafael Espindolabea46262011-01-08 16:42:36 +0000[diff] [blame]867
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]868<p>A global variable may be declared to reside in a target-specific numbered
869 address space. For targets that support them, address spaces may affect how
870 optimizations are performed and/or what target instructions are used to
871 access the variable. The default address space is zero. The address space
872 qualifier must precede any other attributes.</p>
Christopher Lamb284d9922007-12-11 09:31:00 +0000[diff] [blame]873
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]874<p>LLVM allows an explicit section to be specified for globals. If the target
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]875 supports it, it will emit globals to the section specified.</p>
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]876
Chris Lattnerce99fa92010-04-28 00:13:42 +0000[diff] [blame]877<p>An explicit alignment may be specified for a global, which must be a power
878 of 2. If not present, or if the alignment is set to zero, the alignment of
879 the global is set by the target to whatever it feels convenient. If an
880 explicit alignment is specified, the global is forced to have exactly that
Chris Lattner2d4b8ee2010-04-28 00:31:12 +0000[diff] [blame]881 alignment. Targets and optimizers are not allowed to over-align the global
882 if the global has an assigned section. In this case, the extra alignment
883 could be observable: for example, code could assume that the globals are
884 densely packed in their section and try to iterate over them as an array,
885 alignment padding would break this iteration.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]886
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]887<p>For example, the following defines a global in a numbered address space with
888 an initializer, section, and alignment:</p>
Chris Lattner68027ea2007-01-14 00:27:09 +0000[diff] [blame]889
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]890<pre class="doc_code">
Dan Gohman398873c2009-01-11 00:40:00 +0000[diff] [blame]891@G = addrspace(5) constant float 1.0, section "foo", align 4
Chris Lattner68027ea2007-01-14 00:27:09 +0000[diff] [blame]892</pre>
893
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]894</div>
895
896
897<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]898<h3>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]899 <a name="functionstructure">Functions</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]900</h3>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]901
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]902<div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]903
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]904<p>LLVM function definitions consist of the "<tt>define</tt>" keyword, an
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]905 optional <a href="#linkage">linkage type</a>, an optional
906 <a href="#visibility">visibility style</a>, an optional
Rafael Espindolabea46262011-01-08 16:42:36 +0000[diff] [blame]907 <a href="#callingconv">calling convention</a>,
908 an optional <tt>unnamed_addr</tt> attribute, a return type, an optional
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]909 <a href="#paramattrs">parameter attribute</a> for the return type, a function
910 name, a (possibly empty) argument list (each with optional
911 <a href="#paramattrs">parameter attributes</a>), optional
912 <a href="#fnattrs">function attributes</a>, an optional section, an optional
913 alignment, an optional <a href="#gc">garbage collector name</a>, an opening
914 curly brace, a list of basic blocks, and a closing curly brace.</p>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]915
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]916<p>LLVM function declarations consist of the "<tt>declare</tt>" keyword, an
917 optional <a href="#linkage">linkage type</a>, an optional
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]918 <a href="#visibility">visibility style</a>, an optional
Rafael Espindolabea46262011-01-08 16:42:36 +0000[diff] [blame]919 <a href="#callingconv">calling convention</a>,
920 an optional <tt>unnamed_addr</tt> attribute, a return type, an optional
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]921 <a href="#paramattrs">parameter attribute</a> for the return type, a function
922 name, a possibly empty list of arguments, an optional alignment, and an
923 optional <a href="#gc">garbage collector name</a>.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]924
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]925<p>A function definition contains a list of basic blocks, forming the CFG
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]926 (Control Flow Graph) for the function. Each basic block may optionally start
927 with a label (giving the basic block a symbol table entry), contains a list
928 of instructions, and ends with a <a href="#terminators">terminator</a>
929 instruction (such as a branch or function return).</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]930
Chris Lattner4a3c9012007-06-08 16:52:14 +0000[diff] [blame]931<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]932 executed on entrance to the function, and it is not allowed to have
933 predecessor basic blocks (i.e. there can not be any branches to the entry
934 block of a function). Because the block can have no predecessors, it also
935 cannot have any <a href="#i_phi">PHI nodes</a>.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]936
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]937<p>LLVM allows an explicit section to be specified for functions. If the target
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]938 supports it, it will emit functions to the section specified.</p>
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]939
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]940<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]941 the alignment is set to zero, the alignment of the function is set by the
942 target to whatever it feels convenient. If an explicit alignment is
943 specified, the function is forced to have at least that much alignment. All
944 alignments must be a power of 2.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]945
Rafael Espindolabea46262011-01-08 16:42:36 +0000[diff] [blame]946<p>If the <tt>unnamed_addr</tt> attribute is given, the address is know to not
947 be significant and two identical functions can be merged</p>.
948
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]949<h5>Syntax:</h5>
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]950<pre class="doc_code">
Chris Lattner50ad45c2008-10-13 16:55:18 +0000[diff] [blame]951define [<a href="#linkage">linkage</a>] [<a href="#visibility">visibility</a>]
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]952 [<a href="#callingconv">cconv</a>] [<a href="#paramattrs">ret attrs</a>]
953 &lt;ResultType&gt; @&lt;FunctionName&gt; ([argument list])
954 [<a href="#fnattrs">fn Attrs</a>] [section "name"] [align N]
955 [<a href="#gc">gc</a>] { ... }
956</pre>
Devang Patel307e8ab2008-10-07 17:48:33 +0000[diff] [blame]957
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]958</div>
959
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]960<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]961<h3>
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]962 <a name="aliasstructure">Aliases</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]963</h3>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]964
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]965<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]966
967<p>Aliases act as "second name" for the aliasee value (which can be either
968 function, global variable, another alias or bitcast of global value). Aliases
969 may have an optional <a href="#linkage">linkage type</a>, and an
970 optional <a href="#visibility">visibility style</a>.</p>
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]971
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]972<h5>Syntax:</h5>
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]973<pre class="doc_code">
Duncan Sands0b23ac12008-09-12 20:48:21 +0000[diff] [blame]974@&lt;Name&gt; = alias [Linkage] [Visibility] &lt;AliaseeTy&gt; @&lt;Aliasee&gt;
Bill Wendlingaac388b2007-05-29 09:42:13 +0000[diff] [blame]975</pre>
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]976
977</div>
978
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]979<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]980<h3>
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]981 <a name="namedmetadatastructure">Named Metadata</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]982</h3>
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]983
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]984<div>
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]985
Chris Lattnere6a5ddd2010-01-15 21:50:19 +0000[diff] [blame]986<p>Named metadata is a collection of metadata. <a href="#metadata">Metadata
Dan Gohman872814a2010-07-21 18:54:18 +0000[diff] [blame]987 nodes</a> (but not metadata strings) are the only valid operands for
Chris Lattnere6a5ddd2010-01-15 21:50:19 +0000[diff] [blame]988 a named metadata.</p>
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]989
990<h5>Syntax:</h5>
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]991<pre class="doc_code">
Dan Gohman872814a2010-07-21 18:54:18 +0000[diff] [blame]992; Some unnamed metadata nodes, which are referenced by the named metadata.
993!0 = metadata !{metadata !"zero"}
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]994!1 = metadata !{metadata !"one"}
Dan Gohman872814a2010-07-21 18:54:18 +0000[diff] [blame]995!2 = metadata !{metadata !"two"}
Dan Gohman1005bc52010-07-13 19:48:13 +0000[diff] [blame]996; A named metadata.
Dan Gohman872814a2010-07-21 18:54:18 +0000[diff] [blame]997!name = !{!0, !1, !2}
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]998</pre>
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]999
1000</div>
1001
1002<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1003<h3>
1004 <a name="paramattrs">Parameter Attributes</a>
1005</h3>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1006
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1007<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1008
1009<p>The return type and each parameter of a function type may have a set of
1010 <i>parameter attributes</i> associated with them. Parameter attributes are
1011 used to communicate additional information about the result or parameters of
1012 a function. Parameter attributes are considered to be part of the function,
1013 not of the function type, so functions with different parameter attributes
1014 can have the same function type.</p>
1015
1016<p>Parameter attributes are simple keywords that follow the type specified. If
1017 multiple parameter attributes are needed, they are space separated. For
1018 example:</p>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1019
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]1020<pre class="doc_code">
Nick Lewyckyb6a7d252009-02-15 23:06:14 +0000[diff] [blame]1021declare i32 @printf(i8* noalias nocapture, ...)
Chris Lattner66d922c2008-10-04 18:33:34 +0000[diff] [blame]1022declare i32 @atoi(i8 zeroext)
1023declare signext i8 @returns_signed_char()
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1024</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1025
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1026<p>Note that any attributes for the function result (<tt>nounwind</tt>,
1027 <tt>readonly</tt>) come immediately after the argument list.</p>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1028
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1029<p>Currently, only the following parameter attributes are defined:</p>
Chris Lattner47507de2008-01-11 06:20:47 +0000[diff] [blame]1030
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1031<dl>
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1032 <dt><tt><b>zeroext</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1033 <dd>This indicates to the code generator that the parameter or return value
Cameron Zwarichebe81732011-03-16 22:20:18 +0000[diff] [blame]1034 should be zero-extended to the extent required by the target's ABI (which
1035 is usually 32-bits, but is 8-bits for a i1 on x86-64) by the caller (for a
1036 parameter) or the callee (for a return value).</dd>
Chris Lattner47507de2008-01-11 06:20:47 +0000[diff] [blame]1037
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1038 <dt><tt><b>signext</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1039 <dd>This indicates to the code generator that the parameter or return value
Cameron Zwarich9e69ff92011-03-17 14:21:58 +0000[diff] [blame]1040 should be sign-extended to the extent required by the target's ABI (which
1041 is usually 32-bits) by the caller (for a parameter) or the callee (for a
1042 return value).</dd>
Chris Lattner47507de2008-01-11 06:20:47 +0000[diff] [blame]1043
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1044 <dt><tt><b>inreg</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1045 <dd>This indicates that this parameter or return value should be treated in a
1046 special target-dependent fashion during while emitting code for a function
1047 call or return (usually, by putting it in a register as opposed to memory,
1048 though some targets use it to distinguish between two different kinds of
1049 registers). Use of this attribute is target-specific.</dd>
Chris Lattner47507de2008-01-11 06:20:47 +0000[diff] [blame]1050
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1051 <dt><tt><b><a name="byval">byval</a></b></tt></dt>
Chris Lattnera6fd81d2010-11-20 23:49:06 +0000[diff] [blame]1052 <dd><p>This indicates that the pointer parameter should really be passed by
1053 value to the function. The attribute implies that a hidden copy of the
1054 pointee
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1055 is made between the caller and the callee, so the callee is unable to
1056 modify the value in the callee. This attribute is only valid on LLVM
1057 pointer arguments. It is generally used to pass structs and arrays by
1058 value, but is also valid on pointers to scalars. The copy is considered
1059 to belong to the caller not the callee (for example,
1060 <tt><a href="#readonly">readonly</a></tt> functions should not write to
1061 <tt>byval</tt> parameters). This is not a valid attribute for return
Chris Lattnera6fd81d2010-11-20 23:49:06 +0000[diff] [blame]1062 values.</p>
1063
1064 <p>The byval attribute also supports specifying an alignment with
1065 the align attribute. It indicates the alignment of the stack slot to
1066 form and the known alignment of the pointer specified to the call site. If
1067 the alignment is not specified, then the code generator makes a
1068 target-specific assumption.</p></dd>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1069
Dan Gohmanff235352010-07-02 23:18:08 +0000[diff] [blame]1070 <dt><tt><b><a name="sret">sret</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1071 <dd>This indicates that the pointer parameter specifies the address of a
1072 structure that is the return value of the function in the source program.
1073 This pointer must be guaranteed by the caller to be valid: loads and
1074 stores to the structure may be assumed by the callee to not to trap. This
1075 may only be applied to the first parameter. This is not a valid attribute
1076 for return values. </dd>
1077
Dan Gohmanff235352010-07-02 23:18:08 +0000[diff] [blame]1078 <dt><tt><b><a name="noalias">noalias</a></b></tt></dt>
Dan Gohman1e109622010-07-02 18:41:32 +0000[diff] [blame]1079 <dd>This indicates that pointer values
1080 <a href="#pointeraliasing"><i>based</i></a> on the argument or return
Dan Gohmanefca7f92010-07-02 23:46:54 +0000[diff] [blame]1081 value do not alias pointer values which are not <i>based</i> on it,
1082 ignoring certain "irrelevant" dependencies.
1083 For a call to the parent function, dependencies between memory
1084 references from before or after the call and from those during the call
1085 are "irrelevant" to the <tt>noalias</tt> keyword for the arguments and
1086 return value used in that call.
Dan Gohman1e109622010-07-02 18:41:32 +0000[diff] [blame]1087 The caller shares the responsibility with the callee for ensuring that
1088 these requirements are met.
1089 For further details, please see the discussion of the NoAlias response in
Dan Gohmanff70fe42010-07-06 15:26:33 +0000[diff] [blame]1090 <a href="AliasAnalysis.html#MustMayNo">alias analysis</a>.<br>
1091<br>
John McCall191d4ee2010-07-06 21:07:14 +0000[diff] [blame]1092 Note that this definition of <tt>noalias</tt> is intentionally
1093 similar to the definition of <tt>restrict</tt> in C99 for function
Chris Lattner211244a2010-07-06 20:51:35 +0000[diff] [blame]1094 arguments, though it is slightly weaker.
Dan Gohmanff70fe42010-07-06 15:26:33 +0000[diff] [blame]1095<br>
1096 For function return values, C99's <tt>restrict</tt> is not meaningful,
1097 while LLVM's <tt>noalias</tt> is.
1098 </dd>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1099
Dan Gohmanff235352010-07-02 23:18:08 +0000[diff] [blame]1100 <dt><tt><b><a name="nocapture">nocapture</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1101 <dd>This indicates that the callee does not make any copies of the pointer
1102 that outlive the callee itself. This is not a valid attribute for return
1103 values.</dd>
1104
Dan Gohmanff235352010-07-02 23:18:08 +0000[diff] [blame]1105 <dt><tt><b><a name="nest">nest</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1106 <dd>This indicates that the pointer parameter can be excised using the
1107 <a href="#int_trampoline">trampoline intrinsics</a>. This is not a valid
1108 attribute for return values.</dd>
1109</dl>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1110
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1111</div>
1112
1113<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1114<h3>
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]1115 <a name="gc">Garbage Collector Names</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1116</h3>
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]1117
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1118<div>
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]1119
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1120<p>Each function may specify a garbage collector name, which is simply a
1121 string:</p>
1122
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]1123<pre class="doc_code">
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1124define void @f() gc "name" { ... }
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1125</pre>
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]1126
1127<p>The compiler declares the supported values of <i>name</i>. Specifying a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1128 collector which will cause the compiler to alter its output in order to
1129 support the named garbage collection algorithm.</p>
1130
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]1131</div>
1132
1133<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1134<h3>
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1135 <a name="fnattrs">Function Attributes</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1136</h3>
Devang Patelf8b94812008-09-04 23:05:13 +0000[diff] [blame]1137
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1138<div>
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 set to communicate additional information about a
1141 function. Function attributes are considered to be part of the function, not
1142 of the function type, so functions with different parameter attributes can
1143 have the same function type.</p>
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1144
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1145<p>Function attributes are simple keywords that follow the type specified. If
1146 multiple attributes are needed, they are space separated. For example:</p>
Devang Patelf8b94812008-09-04 23:05:13 +0000[diff] [blame]1147
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]1148<pre class="doc_code">
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1149define void @f() noinline { ... }
1150define void @f() alwaysinline { ... }
1151define void @f() alwaysinline optsize { ... }
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1152define void @f() optsize { ... }
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1153</pre>
Devang Patelf8b94812008-09-04 23:05:13 +0000[diff] [blame]1154
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1155<dl>
Charles Davis1e063d12010-02-12 00:31:15 +0000[diff] [blame]1156 <dt><tt><b>alignstack(&lt;<em>n</em>&gt;)</b></tt></dt>
1157 <dd>This attribute indicates that, when emitting the prologue and epilogue,
1158 the backend should forcibly align the stack pointer. Specify the
1159 desired alignment, which must be a power of two, in parentheses.
1160
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1161 <dt><tt><b>alwaysinline</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1162 <dd>This attribute indicates that the inliner should attempt to inline this
1163 function into callers whenever possible, ignoring any active inlining size
1164 threshold for this caller.</dd>
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1165
Charles Davis970bfcc2010-10-25 15:37:09 +0000[diff] [blame]1166 <dt><tt><b>hotpatch</b></tt></dt>
Charles Davis6f12e292010-10-25 16:29:03 +0000[diff] [blame]1167 <dd>This attribute indicates that the function should be 'hotpatchable',
Charles Davis0076d202010-10-25 19:07:39 +0000[diff] [blame]1168 meaning the function can be patched and/or hooked even while it is
1169 loaded into memory. On x86, the function prologue will be preceded
1170 by six bytes of padding and will begin with a two-byte instruction.
1171 Most of the functions in the Windows system DLLs in Windows XP SP2 or
1172 higher were compiled in this fashion.</dd>
Charles Davis970bfcc2010-10-25 15:37:09 +0000[diff] [blame]1173
Dan Gohman129bd562011-06-16 16:03:13 +0000[diff] [blame]1174 <dt><tt><b>nonlazybind</b></tt></dt>
1175 <dd>This attribute suppresses lazy symbol binding for the function. This
1176 may make calls to the function faster, at the cost of extra program
1177 startup time if the function is not called during program startup.</dd>
1178
Jakob Stoklund Olesen570a4a52010-02-06 01:16:28 +0000[diff] [blame]1179 <dt><tt><b>inlinehint</b></tt></dt>
1180 <dd>This attribute indicates that the source code contained a hint that inlining
1181 this function is desirable (such as the "inline" keyword in C/C++). It
1182 is just a hint; it imposes no requirements on the inliner.</dd>
1183
Nick Lewycky76ec37a2010-07-06 18:24:09 +0000[diff] [blame]1184 <dt><tt><b>naked</b></tt></dt>
1185 <dd>This attribute disables prologue / epilogue emission for the function.
1186 This can have very system-specific consequences.</dd>
1187
1188 <dt><tt><b>noimplicitfloat</b></tt></dt>
1189 <dd>This attributes disables implicit floating point instructions.</dd>
1190
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1191 <dt><tt><b>noinline</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1192 <dd>This attribute indicates that the inliner should never inline this
1193 function in any situation. This attribute may not be used together with
1194 the <tt>alwaysinline</tt> attribute.</dd>
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1195
Nick Lewycky76ec37a2010-07-06 18:24:09 +0000[diff] [blame]1196 <dt><tt><b>noredzone</b></tt></dt>
1197 <dd>This attribute indicates that the code generator should not use a red
1198 zone, even if the target-specific ABI normally permits it.</dd>
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1199
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1200 <dt><tt><b>noreturn</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1201 <dd>This function attribute indicates that the function never returns
1202 normally. This produces undefined behavior at runtime if the function
1203 ever does dynamically return.</dd>
Bill Wendling31359ba2008-11-13 01:02:51 +0000[diff] [blame]1204
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1205 <dt><tt><b>nounwind</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1206 <dd>This function attribute indicates that the function never returns with an
1207 unwind or exceptional control flow. If the function does unwind, its
1208 runtime behavior is undefined.</dd>
Bill Wendlingfbaa7ed2008-11-26 19:07:40 +0000[diff] [blame]1209
Nick Lewycky76ec37a2010-07-06 18:24:09 +0000[diff] [blame]1210 <dt><tt><b>optsize</b></tt></dt>
1211 <dd>This attribute suggests that optimization passes and code generator passes
1212 make choices that keep the code size of this function low, and otherwise
1213 do optimizations specifically to reduce code size.</dd>
1214
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1215 <dt><tt><b>readnone</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1216 <dd>This attribute indicates that the function computes its result (or decides
1217 to unwind an exception) based strictly on its arguments, without
1218 dereferencing any pointer arguments or otherwise accessing any mutable
1219 state (e.g. memory, control registers, etc) visible to caller functions.
1220 It does not write through any pointer arguments
1221 (including <tt><a href="#byval">byval</a></tt> arguments) and never
1222 changes any state visible to callers. This means that it cannot unwind
1223 exceptions by calling the <tt>C++</tt> exception throwing methods, but
1224 could use the <tt>unwind</tt> instruction.</dd>
Devang Patel5d96fda2009-06-12 19:45:19 +0000[diff] [blame]1225
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1226 <dt><tt><b><a name="readonly">readonly</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1227 <dd>This attribute indicates that the function does not write through any
1228 pointer arguments (including <tt><a href="#byval">byval</a></tt>
1229 arguments) or otherwise modify any state (e.g. memory, control registers,
1230 etc) visible to caller functions. It may dereference pointer arguments
1231 and read state that may be set in the caller. A readonly function always
1232 returns the same value (or unwinds an exception identically) when called
1233 with the same set of arguments and global state. It cannot unwind an
1234 exception by calling the <tt>C++</tt> exception throwing methods, but may
1235 use the <tt>unwind</tt> instruction.</dd>
Anton Korobeynikovc5ec8a72009-07-17 18:07:26 +0000[diff] [blame]1236
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1237 <dt><tt><b><a name="ssp">ssp</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1238 <dd>This attribute indicates that the function should emit a stack smashing
1239 protector. It is in the form of a "canary"&mdash;a random value placed on
1240 the stack before the local variables that's checked upon return from the
1241 function to see if it has been overwritten. A heuristic is used to
1242 determine if a function needs stack protectors or not.<br>
1243<br>
1244 If a function that has an <tt>ssp</tt> attribute is inlined into a
1245 function that doesn't have an <tt>ssp</tt> attribute, then the resulting
1246 function will have an <tt>ssp</tt> attribute.</dd>
1247
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1248 <dt><tt><b>sspreq</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1249 <dd>This attribute indicates that the function should <em>always</em> emit a
1250 stack smashing protector. This overrides
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1251 the <tt><a href="#ssp">ssp</a></tt> function attribute.<br>
1252<br>
1253 If a function that has an <tt>sspreq</tt> attribute is inlined into a
1254 function that doesn't have an <tt>sspreq</tt> attribute or which has
1255 an <tt>ssp</tt> attribute, then the resulting function will have
1256 an <tt>sspreq</tt> attribute.</dd>
Rafael Espindolafbff0ec2011-07-25 15:27:59 +0000[diff] [blame]1257
1258 <dt><tt><b><a name="uwtable">uwtable</a></b></tt></dt>
1259 <dd>This attribute indicates that the ABI being targeted requires that
1260 an unwind table entry be produce for this function even if we can
1261 show that no exceptions passes by it. This is normally the case for
1262 the ELF x86-64 abi, but it can be disabled for some compilation
1263 units.</dd>
1264
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1265</dl>
1266
Devang Patelf8b94812008-09-04 23:05:13 +0000[diff] [blame]1267</div>
1268
1269<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1270<h3>
Chris Lattner1eeeb0c2006-04-08 04:40:53 +0000[diff] [blame]1271 <a name="moduleasm">Module-Level Inline Assembly</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1272</h3>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1273
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1274<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1275
1276<p>Modules may contain "module-level inline asm" blocks, which corresponds to
1277 the GCC "file scope inline asm" blocks. These blocks are internally
1278 concatenated by LLVM and treated as a single unit, but may be separated in
1279 the <tt>.ll</tt> file if desired. The syntax is very simple:</p>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1280
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]1281<pre class="doc_code">
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1282module asm "inline asm code goes here"
1283module asm "more can go here"
1284</pre>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1285
1286<p>The strings can contain any character by escaping non-printable characters.
1287 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]1288 for the number.</p>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1289
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1290<p>The inline asm code is simply printed to the machine code .s file when
1291 assembly code is generated.</p>
1292
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1293</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1294
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1295<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1296<h3>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1297 <a name="datalayout">Data Layout</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1298</h3>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1299
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1300<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1301
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1302<p>A module may specify a target specific data layout string that specifies how
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1303 data is to be laid out in memory. The syntax for the data layout is
1304 simply:</p>
1305
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]1306<pre class="doc_code">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1307target datalayout = "<i>layout specification</i>"
1308</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1309
1310<p>The <i>layout specification</i> consists of a list of specifications
1311 separated by the minus sign character ('-'). Each specification starts with
1312 a letter and may include other information after the letter to define some
1313 aspect of the data layout. The specifications accepted are as follows:</p>
1314
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1315<dl>
1316 <dt><tt>E</tt></dt>
1317 <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]1318 bits with the most significance have the lowest address location.</dd>
1319
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1320 <dt><tt>e</tt></dt>
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]1321 <dd>Specifies that the target lays out data in little-endian form. That is,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1322 the bits with the least significance have the lowest address
1323 location.</dd>
1324
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1325 <dt><tt>p:<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]1326 <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]1327 <i>preferred</i> alignments. All sizes are in bits. Specifying
1328 the <i>pref</i> alignment is optional. If omitted, the
1329 preceding <tt>:</tt> should be omitted too.</dd>
1330
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1331 <dt><tt>i<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1332 <dd>This specifies the alignment for an integer type of a given bit
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1333 <i>size</i>. The value of <i>size</i> must be in the range [1,2^23).</dd>
1334
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1335 <dt><tt>v<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]1336 <dd>This specifies the alignment for a vector type of a given bit
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1337 <i>size</i>.</dd>
1338
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1339 <dt><tt>f<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]1340 <dd>This specifies the alignment for a floating point type of a given bit
Dale Johannesen9d8d2212010-05-28 18:54:47 +0000[diff] [blame]1341 <i>size</i>. Only values of <i>size</i> that are supported by the target
1342 will work. 32 (float) and 64 (double) are supported on all targets;
1343 80 or 128 (different flavors of long double) are also supported on some
1344 targets.
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1345
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1346 <dt><tt>a<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1347 <dd>This specifies the alignment for an aggregate type of a given bit
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1348 <i>size</i>.</dd>
1349
Daniel Dunbar87bde0b2009-06-08 22:17:53 +0000[diff] [blame]1350 <dt><tt>s<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1351 <dd>This specifies the alignment for a stack object of a given bit
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1352 <i>size</i>.</dd>
Chris Lattnere82bdc42009-11-07 09:35:34 +0000[diff] [blame]1353
1354 <dt><tt>n<i>size1</i>:<i>size2</i>:<i>size3</i>...</tt></dt>
1355 <dd>This specifies a set of native integer widths for the target CPU
1356 in bits. For example, it might contain "n32" for 32-bit PowerPC,
1357 "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]1358 this set are considered to support most general arithmetic
Chris Lattnere82bdc42009-11-07 09:35:34 +0000[diff] [blame]1359 operations efficiently.</dd>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1360</dl>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1361
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1362<p>When constructing the data layout for a given target, LLVM starts with a
Dan Gohman1c70c002010-04-28 00:36:01 +0000[diff] [blame]1363 default set of specifications which are then (possibly) overridden by the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1364 specifications in the <tt>datalayout</tt> keyword. The default specifications
1365 are given in this list:</p>
1366
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1367<ul>
1368 <li><tt>E</tt> - big endian</li>
Dan Gohmanfdf2e8c2010-02-23 02:44:03 +0000[diff] [blame]1369 <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]1370 <li><tt>i1:8:8</tt> - i1 is 8-bit (byte) aligned</li>
1371 <li><tt>i8:8:8</tt> - i8 is 8-bit (byte) aligned</li>
1372 <li><tt>i16:16:16</tt> - i16 is 16-bit aligned</li>
1373 <li><tt>i32:32:32</tt> - i32 is 32-bit aligned</li>
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]1374 <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]1375 alignment of 64-bits</li>
1376 <li><tt>f32:32:32</tt> - float is 32-bit aligned</li>
1377 <li><tt>f64:64:64</tt> - double is 64-bit aligned</li>
1378 <li><tt>v64:64:64</tt> - 64-bit vector is 64-bit aligned</li>
1379 <li><tt>v128:128:128</tt> - 128-bit vector is 128-bit aligned</li>
1380 <li><tt>a0:0:1</tt> - aggregates are 8-bit aligned</li>
Daniel Dunbar87bde0b2009-06-08 22:17:53 +0000[diff] [blame]1381 <li><tt>s0:64:64</tt> - stack objects are 64-bit aligned</li>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1382</ul>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1383
1384<p>When LLVM is determining the alignment for a given type, it uses the
1385 following rules:</p>
1386
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1387<ol>
1388 <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]1389 specification is used.</li>
1390
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1391 <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]1392 smallest integer type that is larger than the bitwidth of the sought type
1393 is used. If none of the specifications are larger than the bitwidth then
1394 the the largest integer type is used. For example, given the default
1395 specifications above, the i7 type will use the alignment of i8 (next
1396 largest) while both i65 and i256 will use the alignment of i64 (largest
1397 specified).</li>
1398
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1399 <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]1400 largest vector type that is smaller than the sought vector type will be
1401 used as a fall back. This happens because &lt;128 x double&gt; can be
1402 implemented in terms of 64 &lt;2 x double&gt;, for example.</li>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1403</ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1404
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1405</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1406
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1407<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1408<h3>
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1409 <a name="pointeraliasing">Pointer Aliasing Rules</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1410</h3>
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1411
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1412<div>
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1413
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1414<p>Any memory access must be done through a pointer value associated
Andreas Bolka99a82052009-07-27 20:37:10 +0000[diff] [blame]1415with an address range of the memory access, otherwise the behavior
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1416is undefined. Pointer values are associated with address ranges
1417according to the following rules:</p>
1418
1419<ul>
Dan Gohman1e109622010-07-02 18:41:32 +0000[diff] [blame]1420 <li>A pointer value is associated with the addresses associated with
1421 any value it is <i>based</i> on.
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1422 <li>An address of a global variable is associated with the address
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1423 range of the variable's storage.</li>
1424 <li>The result value of an allocation instruction is associated with
1425 the address range of the allocated storage.</li>
1426 <li>A null pointer in the default address-space is associated with
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1427 no address.</li>
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1428 <li>An integer constant other than zero or a pointer value returned
1429 from a function not defined within LLVM may be associated with address
1430 ranges allocated through mechanisms other than those provided by
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1431 LLVM. Such ranges shall not overlap with any ranges of addresses
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1432 allocated by mechanisms provided by LLVM.</li>
Dan Gohman1e109622010-07-02 18:41:32 +0000[diff] [blame]1433</ul>
1434
1435<p>A pointer value is <i>based</i> on another pointer value according
1436 to the following rules:</p>
1437
1438<ul>
1439 <li>A pointer value formed from a
1440 <tt><a href="#i_getelementptr">getelementptr</a></tt> operation
1441 is <i>based</i> on the first operand of the <tt>getelementptr</tt>.</li>
1442 <li>The result value of a
1443 <tt><a href="#i_bitcast">bitcast</a></tt> is <i>based</i> on the operand
1444 of the <tt>bitcast</tt>.</li>
1445 <li>A pointer value formed by an
1446 <tt><a href="#i_inttoptr">inttoptr</a></tt> is <i>based</i> on all
1447 pointer values that contribute (directly or indirectly) to the
1448 computation of the pointer's value.</li>
1449 <li>The "<i>based</i> on" relationship is transitive.</li>
1450</ul>
1451
1452<p>Note that this definition of <i>"based"</i> is intentionally
1453 similar to the definition of <i>"based"</i> in C99, though it is
1454 slightly weaker.</p>
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1455
1456<p>LLVM IR does not associate types with memory. The result type of a
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1457<tt><a href="#i_load">load</a></tt> merely indicates the size and
1458alignment of the memory from which to load, as well as the
Dan Gohmanc22c0f32010-06-17 19:23:50 +0000[diff] [blame]1459interpretation of the value. The first operand type of a
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1460<tt><a href="#i_store">store</a></tt> similarly only indicates the size
1461and alignment of the store.</p>
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1462
1463<p>Consequently, type-based alias analysis, aka TBAA, aka
1464<tt>-fstrict-aliasing</tt>, is not applicable to general unadorned
1465LLVM IR. <a href="#metadata">Metadata</a> may be used to encode
1466additional information which specialized optimization passes may use
1467to implement type-based alias analysis.</p>
1468
1469</div>
1470
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]1471<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1472<h3>
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]1473 <a name="volatile">Volatile Memory Accesses</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1474</h3>
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]1475
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1476<div>
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]1477
1478<p>Certain memory accesses, such as <a href="#i_load"><tt>load</tt></a>s, <a
1479href="#i_store"><tt>store</tt></a>s, and <a
1480href="#int_memcpy"><tt>llvm.memcpy</tt></a>s may be marked <tt>volatile</tt>.
1481The optimizers must not change the number of volatile operations or change their
1482order of execution relative to other volatile operations. The optimizers
1483<i>may</i> change the order of volatile operations relative to non-volatile
1484operations. This is not Java's "volatile" and has no cross-thread
1485synchronization behavior.</p>
1486
1487</div>
1488
Eli Friedman5b60e1b2011-07-20 21:35:53 +0000[diff] [blame]1489<!-- ======================================================================= -->
1490<h3>
1491 <a name="memmodel">Memory Model for Concurrent Operations</a>
1492</h3>
1493
1494<div>
1495
1496<p>The LLVM IR does not define any way to start parallel threads of execution
1497or to register signal handlers. Nonetheless, there are platform-specific
1498ways to create them, and we define LLVM IR's behavior in their presence. This
1499model is inspired by the C++0x memory model.</p>
1500
Eli Friedman234bccd2011-08-22 21:35:27 +0000[diff] [blame]1501<p>For a more informal introduction to this model, see the
1502<a href="Atomics.html">LLVM Atomic Instructions and Concurrency Guide</a>.
1503
Eli Friedman5b60e1b2011-07-20 21:35:53 +0000[diff] [blame]1504<p>We define a <i>happens-before</i> partial order as the least partial order
1505that</p>
1506<ul>
1507 <li>Is a superset of single-thread program order, and</li>
1508 <li>When a <i>synchronizes-with</i> <tt>b</tt>, includes an edge from
1509 <tt>a</tt> to <tt>b</tt>. <i>Synchronizes-with</i> pairs are introduced
1510 by platform-specific techniques, like pthread locks, thread
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1511 creation, thread joining, etc., and by atomic instructions.
1512 (See also <a href="#ordering">Atomic Memory Ordering Constraints</a>).
1513 </li>
Eli Friedman5b60e1b2011-07-20 21:35:53 +0000[diff] [blame]1514</ul>
1515
1516<p>Note that program order does not introduce <i>happens-before</i> edges
1517between a thread and signals executing inside that thread.</p>
1518
1519<p>Every (defined) read operation (load instructions, memcpy, atomic
1520loads/read-modify-writes, etc.) <var>R</var> reads a series of bytes written by
1521(defined) write operations (store instructions, atomic
Eli Friedman118973a2011-07-22 03:04:45 +0000[diff] [blame]1522stores/read-modify-writes, memcpy, etc.). For the purposes of this section,
1523initialized globals are considered to have a write of the initializer which is
1524atomic and happens before any other read or write of the memory in question.
1525For each byte of a read <var>R</var>, <var>R<sub>byte</sub></var> may see
1526any write to the same byte, except:</p>
Eli Friedman5b60e1b2011-07-20 21:35:53 +0000[diff] [blame]1527
1528<ul>
1529 <li>If <var>write<sub>1</sub></var> happens before
1530 <var>write<sub>2</sub></var>, and <var>write<sub>2</sub></var> happens
1531 before <var>R<sub>byte</sub></var>, then <var>R<sub>byte</sub></var>
Eli Friedman118973a2011-07-22 03:04:45 +0000[diff] [blame]1532 does not see <var>write<sub>1</sub></var>.
Bill Wendling0246bb72011-07-31 06:45:03 +0000[diff] [blame]1533 <li>If <var>R<sub>byte</sub></var> happens before
1534 <var>write<sub>3</sub></var>, then <var>R<sub>byte</sub></var> does not
1535 see <var>write<sub>3</sub></var>.
Eli Friedman5b60e1b2011-07-20 21:35:53 +0000[diff] [blame]1536</ul>
1537
1538<p>Given that definition, <var>R<sub>byte</sub></var> is defined as follows:
1539<ul>
Eli Friedman234bccd2011-08-22 21:35:27 +0000[diff] [blame]1540 <li>If <var>R</var> is volatile, the result is target-dependent. (Volatile
1541 is supposed to give guarantees which can support
1542 <code>sig_atomic_t</code> in C/C++, and may be used for accesses to
1543 addresses which do not behave like normal memory. It does not generally
1544 provide cross-thread synchronization.)
1545 <li>Otherwise, if there is no write to the same byte that happens before
Eli Friedman5b60e1b2011-07-20 21:35:53 +0000[diff] [blame]1546 <var>R<sub>byte</sub></var>, <var>R<sub>byte</sub></var> returns
1547 <tt>undef</tt> for that byte.
Eli Friedman118973a2011-07-22 03:04:45 +0000[diff] [blame]1548 <li>Otherwise, if <var>R<sub>byte</sub></var> may see exactly one write,
Eli Friedman5b60e1b2011-07-20 21:35:53 +0000[diff] [blame]1549 <var>R<sub>byte</sub></var> returns the value written by that
1550 write.</li>
Eli Friedman118973a2011-07-22 03:04:45 +0000[diff] [blame]1551 <li>Otherwise, if <var>R</var> is atomic, and all the writes
1552 <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]1553 values written. See the <a href="#ordering">Atomic Memory Ordering
1554 Constraints</a> section for additional constraints on how the choice
1555 is made.
Eli Friedman5b60e1b2011-07-20 21:35:53 +0000[diff] [blame]1556 <li>Otherwise <var>R<sub>byte</sub></var> returns <tt>undef</tt>.</li>
1557</ul>
1558
1559<p><var>R</var> returns the value composed of the series of bytes it read.
1560This implies that some bytes within the value may be <tt>undef</tt>
1561<b>without</b> the entire value being <tt>undef</tt>. Note that this only
1562defines the semantics of the operation; it doesn't mean that targets will
1563emit more than one instruction to read the series of bytes.</p>
1564
1565<p>Note that in cases where none of the atomic intrinsics are used, this model
1566places only one restriction on IR transformations on top of what is required
1567for single-threaded execution: introducing a store to a byte which might not
Eli Friedman101c81d2011-08-02 01:15:34 +0000[diff] [blame]1568otherwise be stored is not allowed in general. (Specifically, in the case
1569where another thread might write to and read from an address, introducing a
1570store can change a load that may see exactly one write into a load that may
1571see multiple writes.)</p>
Eli Friedman5b60e1b2011-07-20 21:35:53 +0000[diff] [blame]1572
1573<!-- FIXME: This model assumes all targets where concurrency is relevant have
1574a byte-size store which doesn't affect adjacent bytes. As far as I can tell,
1575none of the backends currently in the tree fall into this category; however,
1576there might be targets which care. If there are, we want a paragraph
1577like the following:
1578
1579Targets may specify that stores narrower than a certain width are not
1580available; on such a target, for the purposes of this model, treat any
1581non-atomic write with an alignment or width less than the minimum width
1582as if it writes to the relevant surrounding bytes.
1583-->
1584
1585</div>
1586
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1587<!-- ======================================================================= -->
NAKAMURA Takumib5bb29c2011-08-12 06:17:17 +0000[diff] [blame]1588<h3>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1589 <a name="ordering">Atomic Memory Ordering Constraints</a>
NAKAMURA Takumib5bb29c2011-08-12 06:17:17 +0000[diff] [blame]1590</h3>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1591
NAKAMURA Takumib5bb29c2011-08-12 06:17:17 +0000[diff] [blame]1592<div>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1593
1594<p>Atomic instructions (<a href="#i_cmpxchg"><code>cmpxchg</code></a>,
Eli Friedman21006d42011-08-09 23:02:53 +0000[diff] [blame]1595<a href="#i_atomicrmw"><code>atomicrmw</code></a>,
1596<a href="#i_fence"><code>fence</code></a>,
1597<a href="#i_load"><code>atomic load</code></a>, and
Eli Friedman8fa281a2011-08-09 23:26:12 +0000[diff] [blame]1598<a href="#i_store"><code>atomic store</code></a>) take an ordering parameter
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1599that determines which other atomic instructions on the same address they
1600<i>synchronize with</i>. These semantics are borrowed from Java and C++0x,
1601but are somewhat more colloquial. If these descriptions aren't precise enough,
Eli Friedman234bccd2011-08-22 21:35:27 +0000[diff] [blame]1602check those specs (see spec references in the
1603<a href="Atomic.html#introduction">atomics guide</a>).
1604<a href="#i_fence"><code>fence</code></a> instructions
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1605treat these orderings somewhat differently since they don't take an address.
1606See that instruction's documentation for details.</p>
1607
Eli Friedman234bccd2011-08-22 21:35:27 +0000[diff] [blame]1608<p>For a simpler introduction to the ordering constraints, see the
1609<a href="Atomics.html">LLVM Atomic Instructions and Concurrency Guide</a>.</p>
1610
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1611<dl>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1612<dt><code>unordered</code></dt>
1613<dd>The set of values that can be read is governed by the happens-before
1614partial order. A value cannot be read unless some operation wrote it.
1615This is intended to provide a guarantee strong enough to model Java's
1616non-volatile shared variables. This ordering cannot be specified for
1617read-modify-write operations; it is not strong enough to make them atomic
1618in any interesting way.</dd>
1619<dt><code>monotonic</code></dt>
1620<dd>In addition to the guarantees of <code>unordered</code>, there is a single
1621total order for modifications by <code>monotonic</code> operations on each
1622address. All modification orders must be compatible with the happens-before
1623order. There is no guarantee that the modification orders can be combined to
1624a global total order for the whole program (and this often will not be
1625possible). The read in an atomic read-modify-write operation
1626(<a href="#i_cmpxchg"><code>cmpxchg</code></a> and
1627<a href="#i_atomicrmw"><code>atomicrmw</code></a>)
1628reads the value in the modification order immediately before the value it
1629writes. If one atomic read happens before another atomic read of the same
1630address, the later read must see the same value or a later value in the
1631address's modification order. This disallows reordering of
1632<code>monotonic</code> (or stronger) operations on the same address. If an
1633address is written <code>monotonic</code>ally by one thread, and other threads
1634<code>monotonic</code>ally read that address repeatedly, the other threads must
Eli Friedman234bccd2011-08-22 21:35:27 +0000[diff] [blame]1635eventually see the write. This corresponds to the C++0x/C1x
1636<code>memory_order_relaxed</code>.</dd>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1637<dt><code>acquire</code></dt>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1638<dd>In addition to the guarantees of <code>monotonic</code>,
Eli Friedmanc264b2f2011-08-24 20:28:39 +0000[diff] [blame]1639a <i>synchronizes-with</i> edge may be formed with a <code>release</code>
1640operation. This is intended to model C++'s <code>memory_order_acquire</code>.</dd>
1641<dt><code>release</code></dt>
1642<dd>In addition to the guarantees of <code>monotonic</code>, if this operation
1643writes a value which is subsequently read by an <code>acquire</code> operation,
1644it <i>synchronizes-with</i> that operation. (This isn't a complete
1645description; see the C++0x definition of a release sequence.) This corresponds
1646to the C++0x/C1x <code>memory_order_release</code>.</dd>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1647<dt><code>acq_rel</code> (acquire+release)</dt><dd>Acts as both an
Eli Friedman234bccd2011-08-22 21:35:27 +0000[diff] [blame]1648<code>acquire</code> and <code>release</code> operation on its address.
1649This corresponds to the C++0x/C1x <code>memory_order_acq_rel</code>.</dd>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1650<dt><code>seq_cst</code> (sequentially consistent)</dt><dd>
1651<dd>In addition to the guarantees of <code>acq_rel</code>
1652(<code>acquire</code> for an operation which only reads, <code>release</code>
1653for an operation which only writes), there is a global total order on all
1654sequentially-consistent operations on all addresses, which is consistent with
1655the <i>happens-before</i> partial order and with the modification orders of
1656all the affected addresses. Each sequentially-consistent read sees the last
Eli Friedman234bccd2011-08-22 21:35:27 +0000[diff] [blame]1657preceding write to the same address in this global order. This corresponds
1658to the C++0x/C1x <code>memory_order_seq_cst</code> and Java volatile.</dd>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1659</dl>
1660
1661<p id="singlethread">If an atomic operation is marked <code>singlethread</code>,
1662it only <i>synchronizes with</i> or participates in modification and seq_cst
1663total orderings with other operations running in the same thread (for example,
1664in signal handlers).</p>
1665
1666</div>
1667
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1668</div>
1669
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1670<!-- *********************************************************************** -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1671<h2><a name="typesystem">Type System</a></h2>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1672<!-- *********************************************************************** -->
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1673
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1674<div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1675
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1676<p>The LLVM type system is one of the most important features of the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1677 intermediate representation. Being typed enables a number of optimizations
1678 to be performed on the intermediate representation directly, without having
1679 to do extra analyses on the side before the transformation. A strong type
1680 system makes it easier to read the generated code and enables novel analyses
1681 and transformations that are not feasible to perform on normal three address
1682 code representations.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1683
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1684<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1685<h3>
1686 <a name="t_classifications">Type Classifications</a>
1687</h3>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1688
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1689<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1690
1691<p>The types fall into a few useful classifications:</p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1692
1693<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1694 <tbody>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1695 <tr><th>Classification</th><th>Types</th></tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1696 <tr>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1697 <td><a href="#t_integer">integer</a></td>
Reid Spencer2b916312007-05-16 18:44:01 +0000[diff] [blame]1698 <td><tt>i1, i2, i3, ... i8, ... i16, ... i32, ... i64, ... </tt></td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1699 </tr>
1700 <tr>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1701 <td><a href="#t_floating">floating point</a></td>
1702 <td><tt>float, double, x86_fp80, fp128, ppc_fp128</tt></td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1703 </tr>
1704 <tr>
1705 <td><a name="t_firstclass">first class</a></td>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1706 <td><a href="#t_integer">integer</a>,
1707 <a href="#t_floating">floating point</a>,
1708 <a href="#t_pointer">pointer</a>,
Dan Gohman0066db62008-06-18 18:42:13 +0000[diff] [blame]1709 <a href="#t_vector">vector</a>,
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]1710 <a href="#t_struct">structure</a>,
1711 <a href="#t_array">array</a>,
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1712 <a href="#t_label">label</a>,
1713 <a href="#t_metadata">metadata</a>.
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1714 </td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1715 </tr>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1716 <tr>
1717 <td><a href="#t_primitive">primitive</a></td>
1718 <td><a href="#t_label">label</a>,
1719 <a href="#t_void">void</a>,
Tobias Grosser05387292010-12-28 20:29:31 +0000[diff] [blame]1720 <a href="#t_integer">integer</a>,
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1721 <a href="#t_floating">floating point</a>,
Dale Johannesen21fe99b2010-10-01 00:48:59 +0000[diff] [blame]1722 <a href="#t_x86mmx">x86mmx</a>,
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1723 <a href="#t_metadata">metadata</a>.</td>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1724 </tr>
1725 <tr>
1726 <td><a href="#t_derived">derived</a></td>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]1727 <td><a href="#t_array">array</a>,
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1728 <a href="#t_function">function</a>,
1729 <a href="#t_pointer">pointer</a>,
1730 <a href="#t_struct">structure</a>,
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1731 <a href="#t_vector">vector</a>,
1732 <a href="#t_opaque">opaque</a>.
Dan Gohman01ac1012008-10-14 16:32:04 +0000[diff] [blame]1733 </td>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1734 </tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1735 </tbody>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1736</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1737
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1738<p>The <a href="#t_firstclass">first class</a> types are perhaps the most
1739 important. Values of these types are the only ones which can be produced by
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]1740 instructions.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1741
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1742</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1743
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1744<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1745<h3>
1746 <a name="t_primitive">Primitive Types</a>
1747</h3>
Chris Lattner8f8c7b72008-01-04 04:34:14 +0000[diff] [blame]1748
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1749<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1750
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1751<p>The primitive types are the fundamental building blocks of the LLVM
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1752 system.</p>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1753
1754<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1755<h4>
1756 <a name="t_integer">Integer Type</a>
1757</h4>
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]1758
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1759<div>
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]1760
1761<h5>Overview:</h5>
1762<p>The integer type is a very simple type that simply specifies an arbitrary
1763 bit width for the integer type desired. Any bit width from 1 bit to
1764 2<sup>23</sup>-1 (about 8 million) can be specified.</p>
1765
1766<h5>Syntax:</h5>
1767<pre>
1768 iN
1769</pre>
1770
1771<p>The number of bits the integer will occupy is specified by the <tt>N</tt>
1772 value.</p>
1773
1774<h5>Examples:</h5>
1775<table class="layout">
1776 <tr class="layout">
1777 <td class="left"><tt>i1</tt></td>
1778 <td class="left">a single-bit integer.</td>
1779 </tr>
1780 <tr class="layout">
1781 <td class="left"><tt>i32</tt></td>
1782 <td class="left">a 32-bit integer.</td>
1783 </tr>
1784 <tr class="layout">
1785 <td class="left"><tt>i1942652</tt></td>
1786 <td class="left">a really big integer of over 1 million bits.</td>
1787 </tr>
1788</table>
1789
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]1790</div>
1791
1792<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1793<h4>
1794 <a name="t_floating">Floating Point Types</a>
1795</h4>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1796
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1797<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1798
1799<table>
1800 <tbody>
1801 <tr><th>Type</th><th>Description</th></tr>
1802 <tr><td><tt>float</tt></td><td>32-bit floating point value</td></tr>
1803 <tr><td><tt>double</tt></td><td>64-bit floating point value</td></tr>
1804 <tr><td><tt>fp128</tt></td><td>128-bit floating point value (112-bit mantissa)</td></tr>
1805 <tr><td><tt>x86_fp80</tt></td><td>80-bit floating point value (X87)</td></tr>
1806 <tr><td><tt>ppc_fp128</tt></td><td>128-bit floating point value (two 64-bits)</td></tr>
1807 </tbody>
1808</table>
1809
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1810</div>
1811
1812<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1813<h4>
1814 <a name="t_x86mmx">X86mmx Type</a>
1815</h4>
Dale Johannesen21fe99b2010-10-01 00:48:59 +0000[diff] [blame]1816
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1817<div>
Dale Johannesen21fe99b2010-10-01 00:48:59 +0000[diff] [blame]1818
1819<h5>Overview:</h5>
1820<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>
1821
1822<h5>Syntax:</h5>
1823<pre>
Dale Johannesen473a8c82010-10-01 01:07:02 +0000[diff] [blame]1824 x86mmx
Dale Johannesen21fe99b2010-10-01 00:48:59 +0000[diff] [blame]1825</pre>
1826
1827</div>
1828
1829<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1830<h4>
1831 <a name="t_void">Void Type</a>
1832</h4>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1833
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1834<div>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1835
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1836<h5>Overview:</h5>
1837<p>The void type does not represent any value and has no size.</p>
1838
1839<h5>Syntax:</h5>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1840<pre>
1841 void
1842</pre>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1843
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1844</div>
1845
1846<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1847<h4>
1848 <a name="t_label">Label Type</a>
1849</h4>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1850
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1851<div>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1852
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1853<h5>Overview:</h5>
1854<p>The label type represents code labels.</p>
1855
1856<h5>Syntax:</h5>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1857<pre>
1858 label
1859</pre>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1860
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1861</div>
1862
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1863<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1864<h4>
1865 <a name="t_metadata">Metadata Type</a>
1866</h4>
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1867
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1868<div>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1869
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1870<h5>Overview:</h5>
Nick Lewyckyc261df92009-09-27 23:27:42 +0000[diff] [blame]1871<p>The metadata type represents embedded metadata. No derived types may be
1872 created from metadata except for <a href="#t_function">function</a>
1873 arguments.
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1874
1875<h5>Syntax:</h5>
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1876<pre>
1877 metadata
1878</pre>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1879
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1880</div>
1881
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1882</div>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1883
1884<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1885<h3>
1886 <a name="t_derived">Derived Types</a>
1887</h3>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1888
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1889<div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1890
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1891<p>The real power in LLVM comes from the derived types in the system. This is
1892 what allows a programmer to represent arrays, functions, pointers, and other
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]1893 useful types. Each of these types contain one or more element types which
1894 may be a primitive type, or another derived type. For example, it is
1895 possible to have a two dimensional array, using an array as the element type
1896 of another array.</p>
Dan Gohmand8791e52009-01-24 15:58:40 +0000[diff] [blame]1897
Chris Lattner1afcace2011-07-09 17:41:24 +0000[diff] [blame]1898</div>
1899
1900
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]1901<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1902<h4>
1903 <a name="t_aggregate">Aggregate Types</a>
1904</h4>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]1905
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1906<div>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]1907
1908<p>Aggregate Types are a subset of derived types that can contain multiple
1909 member types. <a href="#t_array">Arrays</a>,
Chris Lattner61c70e92010-08-28 04:09:24 +0000[diff] [blame]1910 <a href="#t_struct">structs</a>, and <a href="#t_vector">vectors</a> are
1911 aggregate types.</p>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]1912
1913</div>
1914
Reid Spencer2b916312007-05-16 18:44:01 +0000[diff] [blame]1915<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1916<h4>
1917 <a name="t_array">Array Type</a>
1918</h4>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1919
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1920<div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1921
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1922<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1923<p>The array type is a very simple derived type that arranges elements
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1924 sequentially in memory. The array type requires a size (number of elements)
1925 and an underlying data type.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1926
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1927<h5>Syntax:</h5>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1928<pre>
1929 [&lt;# elements&gt; x &lt;elementtype&gt;]
1930</pre>
1931
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1932<p>The number of elements is a constant integer value; <tt>elementtype</tt> may
1933 be any type with a size.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1934
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1935<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1936<table class="layout">
1937 <tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1938 <td class="left"><tt>[40 x i32]</tt></td>
1939 <td class="left">Array of 40 32-bit integer values.</td>
1940 </tr>
1941 <tr class="layout">
1942 <td class="left"><tt>[41 x i32]</tt></td>
1943 <td class="left">Array of 41 32-bit integer values.</td>
1944 </tr>
1945 <tr class="layout">
1946 <td class="left"><tt>[4 x i8]</tt></td>
1947 <td class="left">Array of 4 8-bit integer values.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1948 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1949</table>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1950<p>Here are some examples of multidimensional arrays:</p>
1951<table class="layout">
1952 <tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1953 <td class="left"><tt>[3 x [4 x i32]]</tt></td>
1954 <td class="left">3x4 array of 32-bit integer values.</td>
1955 </tr>
1956 <tr class="layout">
1957 <td class="left"><tt>[12 x [10 x float]]</tt></td>
1958 <td class="left">12x10 array of single precision floating point values.</td>
1959 </tr>
1960 <tr class="layout">
1961 <td class="left"><tt>[2 x [3 x [4 x i16]]]</tt></td>
1962 <td class="left">2x3x4 array of 16-bit integer values.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1963 </tr>
1964</table>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]1965
Dan Gohman7657f6b2009-11-09 19:01:53 +0000[diff] [blame]1966<p>There is no restriction on indexing beyond the end of the array implied by
1967 a static type (though there are restrictions on indexing beyond the bounds
1968 of an allocated object in some cases). This means that single-dimension
1969 'variable sized array' addressing can be implemented in LLVM with a zero
1970 length array type. An implementation of 'pascal style arrays' in LLVM could
1971 use the type "<tt>{ i32, [0 x float]}</tt>", for example.</p>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]1972
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1973</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1974
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1975<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1976<h4>
1977 <a name="t_function">Function Type</a>
1978</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1979
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1980<div>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]1981
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1982<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1983<p>The function type can be thought of as a function signature. It consists of
1984 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]1985 function type is a first class type or a void type.</p>
Devang Patelc3fc6df2008-03-10 20:49:15 +0000[diff] [blame]1986
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1987<h5>Syntax:</h5>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]1988<pre>
Nick Lewycky51386942009-09-27 07:55:32 +0000[diff] [blame]1989 &lt;returntype&gt; (&lt;parameter list&gt;)
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]1990</pre>
1991
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]1992<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]1993 specifiers. Optionally, the parameter list may include a type <tt>...</tt>,
1994 which indicates that the function takes a variable number of arguments.
1995 Variable argument functions can access their arguments with
1996 the <a href="#int_varargs">variable argument handling intrinsic</a>
Chris Lattner0724fbd2010-03-02 06:36:51 +0000[diff] [blame]1997 functions. '<tt>&lt;returntype&gt;</tt>' is any type except
Nick Lewyckyc261df92009-09-27 23:27:42 +0000[diff] [blame]1998 <a href="#t_label">label</a>.</p>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]1999
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2000<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]2001<table class="layout">
2002 <tr class="layout">
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]2003 <td class="left"><tt>i32 (i32)</tt></td>
2004 <td class="left">function taking an <tt>i32</tt>, returning an <tt>i32</tt>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]2005 </td>
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]2006 </tr><tr class="layout">
Chris Lattner0724fbd2010-03-02 06:36:51 +0000[diff] [blame]2007 <td class="left"><tt>float&nbsp;(i16,&nbsp;i32&nbsp;*)&nbsp;*
Reid Spencerf17a0b72006-12-31 07:20:23 +0000[diff] [blame]2008 </tt></td>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]2009 <td class="left"><a href="#t_pointer">Pointer</a> to a function that takes
Chris Lattner0724fbd2010-03-02 06:36:51 +0000[diff] [blame]2010 an <tt>i16</tt> and a <a href="#t_pointer">pointer</a> to <tt>i32</tt>,
2011 returning <tt>float</tt>.
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]2012 </td>
2013 </tr><tr class="layout">
2014 <td class="left"><tt>i32 (i8*, ...)</tt></td>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]2015 <td class="left">A vararg function that takes at least one
2016 <a href="#t_pointer">pointer</a> to <tt>i8 </tt> (char in C),
2017 which returns an integer. This is the signature for <tt>printf</tt> in
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]2018 LLVM.
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]2019 </td>
Devang Patela582f402008-03-24 05:35:41 +0000[diff] [blame]2020 </tr><tr class="layout">
2021 <td class="left"><tt>{i32, i32} (i32)</tt></td>
Nick Lewycky51386942009-09-27 07:55:32 +0000[diff] [blame]2022 <td class="left">A function taking an <tt>i32</tt>, returning a
2023 <a href="#t_struct">structure</a> containing two <tt>i32</tt> values
Devang Patela582f402008-03-24 05:35:41 +0000[diff] [blame]2024 </td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]2025 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2026</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]2027
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2028</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2029
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2030<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2031<h4>
2032 <a name="t_struct">Structure Type</a>
2033</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2034
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2035<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2036
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2037<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2038<p>The structure type is used to represent a collection of data members together
Chris Lattner1afcace2011-07-09 17:41:24 +0000[diff] [blame]2039 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]2040
Jeffrey Yasskin7a088cf2010-01-11 19:19:26 +0000[diff] [blame]2041<p>Structures in memory are accessed using '<tt><a href="#i_load">load</a></tt>'
2042 and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a field
2043 with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.
2044 Structures in registers are accessed using the
2045 '<tt><a href="#i_extractvalue">extractvalue</a></tt>' and
2046 '<tt><a href="#i_insertvalue">insertvalue</a></tt>' instructions.</p>
Chris Lattner1afcace2011-07-09 17:41:24 +0000[diff] [blame]2047
2048<p>Structures may optionally be "packed" structures, which indicate that the
2049 alignment of the struct is one byte, and that there is no padding between
Chris Lattner2c38d652011-08-12 17:31:02 +0000[diff] [blame]2050 the elements. In non-packed structs, padding between field types is inserted
2051 as defined by the TargetData string in the module, which is required to match
2052 what the underlying processor expects.</p>
Chris Lattner1afcace2011-07-09 17:41:24 +0000[diff] [blame]2053
Chris Lattner2c38d652011-08-12 17:31:02 +0000[diff] [blame]2054<p>Structures can either be "literal" or "identified". A literal structure is
2055 defined inline with other types (e.g. <tt>{i32, i32}*</tt>) whereas identified
2056 types are always defined at the top level with a name. Literal types are
2057 uniqued by their contents and can never be recursive or opaque since there is
Chris Lattneraa175c32011-08-12 18:12:40 +0000[diff] [blame]2058 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]2059 never uniqued.
Chris Lattner1afcace2011-07-09 17:41:24 +0000[diff] [blame]2060</p>
2061
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2062<h5>Syntax:</h5>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]2063<pre>
Chris Lattner2c38d652011-08-12 17:31:02 +0000[diff] [blame]2064 %T1 = type { &lt;type list&gt; } <i>; Identified normal struct type</i>
2065 %T2 = type &lt;{ &lt;type list&gt; }&gt; <i>; Identified packed struct type</i>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]2066</pre>
Chris Lattner1afcace2011-07-09 17:41:24 +0000[diff] [blame]2067
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2068<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]2069<table class="layout">
2070 <tr class="layout">
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]2071 <td class="left"><tt>{ i32, i32, i32 }</tt></td>
2072 <td class="left">A triple of three <tt>i32</tt> values</td>
Chris Lattner1afcace2011-07-09 17:41:24 +0000[diff] [blame]2073 </tr>
2074 <tr class="layout">
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]2075 <td class="left"><tt>{&nbsp;float,&nbsp;i32&nbsp;(i32)&nbsp;*&nbsp;}</tt></td>
2076 <td class="left">A pair, where the first element is a <tt>float</tt> and the
2077 second element is a <a href="#t_pointer">pointer</a> to a
2078 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
2079 an <tt>i32</tt>.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]2080 </tr>
Chris Lattner1afcace2011-07-09 17:41:24 +0000[diff] [blame]2081 <tr class="layout">
2082 <td class="left"><tt>&lt;{ i8, i32 }&gt;</tt></td>
2083 <td class="left">A packed struct known to be 5 bytes in size.</td>
2084 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2085</table>
Dan Gohmand8791e52009-01-24 15:58:40 +0000[diff] [blame]2086
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2087</div>
Chris Lattner1afcace2011-07-09 17:41:24 +0000[diff] [blame]2088
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2089<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2090<h4>
Chris Lattner628ed392011-07-23 19:59:08 +0000[diff] [blame]2091 <a name="t_opaque">Opaque Structure Types</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2092</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2093
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2094<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2095
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]2096<h5>Overview:</h5>
Chris Lattner628ed392011-07-23 19:59:08 +0000[diff] [blame]2097<p>Opaque structure types are used to represent named structure types that do
2098 not have a body specified. This corresponds (for example) to the C notion of
2099 a forward declared structure.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2100
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]2101<h5>Syntax:</h5>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]2102<pre>
Chris Lattner1afcace2011-07-09 17:41:24 +0000[diff] [blame]2103 %X = type opaque
2104 %52 = type opaque
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]2105</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2106
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]2107<h5>Examples:</h5>
2108<table class="layout">
2109 <tr class="layout">
Chris Lattner1afcace2011-07-09 17:41:24 +0000[diff] [blame]2110 <td class="left"><tt>opaque</tt></td>
2111 <td class="left">An opaque type.</td>
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]2112 </tr>
2113</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2114
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]2115</div>
2116
Chris Lattner1afcace2011-07-09 17:41:24 +0000[diff] [blame]2117
2118
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]2119<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2120<h4>
2121 <a name="t_pointer">Pointer Type</a>
2122</h4>
Chris Lattner0fd4a272009-02-08 19:53:29 +0000[diff] [blame]2123
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2124<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2125
2126<h5>Overview:</h5>
Dan Gohmanff3ef322010-02-25 16:50:07 +0000[diff] [blame]2127<p>The pointer type is used to specify memory locations.
2128 Pointers are commonly used to reference objects in memory.</p>
2129
2130<p>Pointer types may have an optional address space attribute defining the
2131 numbered address space where the pointed-to object resides. The default
2132 address space is number zero. The semantics of non-zero address
2133 spaces are target-specific.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2134
2135<p>Note that LLVM does not permit pointers to void (<tt>void*</tt>) nor does it
2136 permit pointers to labels (<tt>label*</tt>). Use <tt>i8*</tt> instead.</p>
Chris Lattner0fd4a272009-02-08 19:53:29 +0000[diff] [blame]2137
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2138<h5>Syntax:</h5>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]2139<pre>
2140 &lt;type&gt; *
2141</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2142
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2143<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]2144<table class="layout">
2145 <tr class="layout">
Dan Gohman2a08c532009-01-04 23:44:43 +0000[diff] [blame]2146 <td class="left"><tt>[4 x i32]*</tt></td>
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]2147 <td class="left">A <a href="#t_pointer">pointer</a> to <a
2148 href="#t_array">array</a> of four <tt>i32</tt> values.</td>
2149 </tr>
2150 <tr class="layout">
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]2151 <td class="left"><tt>i32 (i32*) *</tt></td>
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]2152 <td class="left"> A <a href="#t_pointer">pointer</a> to a <a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2153 href="#t_function">function</a> that takes an <tt>i32*</tt>, returning an
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]2154 <tt>i32</tt>.</td>
2155 </tr>
2156 <tr class="layout">
2157 <td class="left"><tt>i32 addrspace(5)*</tt></td>
2158 <td class="left">A <a href="#t_pointer">pointer</a> to an <tt>i32</tt> value
2159 that resides in address space #5.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]2160 </tr>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2161</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2162
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2163</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]2164
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]2165<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2166<h4>
2167 <a name="t_vector">Vector Type</a>
2168</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2169
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2170<div>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]2171
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]2172<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2173<p>A vector type is a simple derived type that represents a vector of elements.
2174 Vector types are used when multiple primitive data are operated in parallel
2175 using a single instruction (SIMD). A vector type requires a size (number of
Duncan Sandsd40d14e2009-11-27 13:38:03 +0000[diff] [blame]2176 elements) and an underlying primitive data type. Vector types are considered
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2177 <a href="#t_firstclass">first class</a>.</p>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]2178
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]2179<h5>Syntax:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]2180<pre>
2181 &lt; &lt;# elements&gt; x &lt;elementtype&gt; &gt;
2182</pre>
2183
Chris Lattner7d2e7be2010-10-10 18:20:35 +0000[diff] [blame]2184<p>The number of elements is a constant integer value larger than 0; elementtype
2185 may be any integer or floating point type. Vectors of size zero are not
2186 allowed, and pointers are not allowed as the element type.</p>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]2187
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]2188<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]2189<table class="layout">
2190 <tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]2191 <td class="left"><tt>&lt;4 x i32&gt;</tt></td>
2192 <td class="left">Vector of 4 32-bit integer values.</td>
2193 </tr>
2194 <tr class="layout">
2195 <td class="left"><tt>&lt;8 x float&gt;</tt></td>
2196 <td class="left">Vector of 8 32-bit floating-point values.</td>
2197 </tr>
2198 <tr class="layout">
2199 <td class="left"><tt>&lt;2 x i64&gt;</tt></td>
2200 <td class="left">Vector of 2 64-bit integer values.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]2201 </tr>
2202</table>
Dan Gohmand8791e52009-01-24 15:58:40 +0000[diff] [blame]2203
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2204</div>
2205
Bill Wendlingaf75f0c2011-07-31 06:47:33 +0000[diff] [blame]2206</div>
2207
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2208<!-- *********************************************************************** -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2209<h2><a name="constants">Constants</a></h2>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2210<!-- *********************************************************************** -->
2211
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2212<div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2213
2214<p>LLVM has several different basic types of constants. This section describes
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2215 them all and their syntax.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2216
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2217<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2218<h3>
2219 <a name="simpleconstants">Simple Constants</a>
2220</h3>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2221
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2222<div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2223
2224<dl>
2225 <dt><b>Boolean constants</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2226 <dd>The two strings '<tt>true</tt>' and '<tt>false</tt>' are both valid
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]2227 constants of the <tt><a href="#t_integer">i1</a></tt> type.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2228
2229 <dt><b>Integer constants</b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2230 <dd>Standard integers (such as '4') are constants of
2231 the <a href="#t_integer">integer</a> type. Negative numbers may be used
2232 with integer types.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2233
2234 <dt><b>Floating point constants</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2235 <dd>Floating point constants use standard decimal notation (e.g. 123.421),
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2236 exponential notation (e.g. 1.23421e+2), or a more precise hexadecimal
2237 notation (see below). The assembler requires the exact decimal value of a
2238 floating-point constant. For example, the assembler accepts 1.25 but
2239 rejects 1.3 because 1.3 is a repeating decimal in binary. Floating point
2240 constants must have a <a href="#t_floating">floating point</a> type. </dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2241
2242 <dt><b>Null pointer constants</b></dt>
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]2243 <dd>The identifier '<tt>null</tt>' is recognized as a null pointer constant
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2244 and must be of <a href="#t_pointer">pointer type</a>.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2245</dl>
2246
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2247<p>The one non-intuitive notation for constants is the hexadecimal form of
2248 floating point constants. For example, the form '<tt>double
2249 0x432ff973cafa8000</tt>' is equivalent to (but harder to read than)
2250 '<tt>double 4.5e+15</tt>'. The only time hexadecimal floating point
2251 constants are required (and the only time that they are generated by the
2252 disassembler) is when a floating point constant must be emitted but it cannot
2253 be represented as a decimal floating point number in a reasonable number of
2254 digits. For example, NaN's, infinities, and other special values are
2255 represented in their IEEE hexadecimal format so that assembly and disassembly
2256 do not cause any bits to change in the constants.</p>
2257
Dale Johannesenbd5e5a82009-02-11 22:14:51 +0000[diff] [blame]2258<p>When using the hexadecimal form, constants of types float and double are
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2259 represented using the 16-digit form shown above (which matches the IEEE754
2260 representation for double); float values must, however, be exactly
2261 representable as IEE754 single precision. Hexadecimal format is always used
2262 for long double, and there are three forms of long double. The 80-bit format
2263 used by x86 is represented as <tt>0xK</tt> followed by 20 hexadecimal digits.
2264 The 128-bit format used by PowerPC (two adjacent doubles) is represented
2265 by <tt>0xM</tt> followed by 32 hexadecimal digits. The IEEE 128-bit format
2266 is represented by <tt>0xL</tt> followed by 32 hexadecimal digits; no
2267 currently supported target uses this format. Long doubles will only work if
2268 they match the long double format on your target. All hexadecimal formats
2269 are big-endian (sign bit at the left).</p>
2270
Dale Johannesen21fe99b2010-10-01 00:48:59 +0000[diff] [blame]2271<p>There are no constants of type x86mmx.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2272</div>
2273
2274<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2275<h3>
Bill Wendlingd9fe2982009-07-20 02:32:41 +0000[diff] [blame]2276<a name="aggregateconstants"></a> <!-- old anchor -->
2277<a name="complexconstants">Complex Constants</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2278</h3>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2279
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2280<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2281
Chris Lattner70882792009-02-28 18:32:25 +0000[diff] [blame]2282<p>Complex constants are a (potentially recursive) combination of simple
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2283 constants and smaller complex constants.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2284
2285<dl>
2286 <dt><b>Structure constants</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2287 <dd>Structure constants are represented with notation similar to structure
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2288 type definitions (a comma separated list of elements, surrounded by braces
2289 (<tt>{}</tt>)). For example: "<tt>{ i32 4, float 17.0, i32* @G }</tt>",
2290 where "<tt>@G</tt>" is declared as "<tt>@G = external global i32</tt>".
2291 Structure constants must have <a href="#t_struct">structure type</a>, and
2292 the number and types of elements must match those specified by the
2293 type.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2294
2295 <dt><b>Array constants</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2296 <dd>Array constants are represented with notation similar to array type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2297 definitions (a comma separated list of elements, surrounded by square
2298 brackets (<tt>[]</tt>)). For example: "<tt>[ i32 42, i32 11, i32 74
2299 ]</tt>". Array constants must have <a href="#t_array">array type</a>, and
2300 the number and types of elements must match those specified by the
2301 type.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2302
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2303 <dt><b>Vector constants</b></dt>
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2304 <dd>Vector constants are represented with notation similar to vector type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2305 definitions (a comma separated list of elements, surrounded by
2306 less-than/greater-than's (<tt>&lt;&gt;</tt>)). For example: "<tt>&lt; i32
2307 42, i32 11, i32 74, i32 100 &gt;</tt>". Vector constants must
2308 have <a href="#t_vector">vector type</a>, and the number and types of
2309 elements must match those specified by the type.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2310
2311 <dt><b>Zero initialization</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2312 <dd>The string '<tt>zeroinitializer</tt>' can be used to zero initialize a
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]2313 value to zero of <em>any</em> type, including scalar and
2314 <a href="#t_aggregate">aggregate</a> types.
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2315 This is often used to avoid having to print large zero initializers
2316 (e.g. for large arrays) and is always exactly equivalent to using explicit
2317 zero initializers.</dd>
Nick Lewycky21cc4462009-04-04 07:22:01 +0000[diff] [blame]2318
2319 <dt><b>Metadata node</b></dt>
Nick Lewycky1e8c7a62009-05-30 16:08:30 +0000[diff] [blame]2320 <dd>A metadata node is a structure-like constant with
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2321 <a href="#t_metadata">metadata type</a>. For example: "<tt>metadata !{
2322 i32 0, metadata !"test" }</tt>". Unlike other constants that are meant to
2323 be interpreted as part of the instruction stream, metadata is a place to
2324 attach additional information such as debug info.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2325</dl>
2326
2327</div>
2328
2329<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2330<h3>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2331 <a name="globalconstants">Global Variable and Function Addresses</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2332</h3>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2333
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2334<div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2335
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2336<p>The addresses of <a href="#globalvars">global variables</a>
2337 and <a href="#functionstructure">functions</a> are always implicitly valid
2338 (link-time) constants. These constants are explicitly referenced when
2339 the <a href="#identifiers">identifier for the global</a> is used and always
2340 have <a href="#t_pointer">pointer</a> type. For example, the following is a
2341 legal LLVM file:</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2342
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2343<pre class="doc_code">
Chris Lattnera18a4242007-06-06 18:28:13 +0000[diff] [blame]2344@X = global i32 17
2345@Y = global i32 42
2346@Z = global [2 x i32*] [ i32* @X, i32* @Y ]
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2347</pre>
2348
2349</div>
2350
2351<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2352<h3>
2353 <a name="undefvalues">Undefined Values</a>
2354</h3>
2355
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2356<div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2357
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2358<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]2359 indicates that the user of the value may receive an unspecified bit-pattern.
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]2360 Undefined values may be of any type (other than '<tt>label</tt>'
2361 or '<tt>void</tt>') and be used anywhere a constant is permitted.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2362
Chris Lattnerc608cb12009-09-11 01:49:31 +0000[diff] [blame]2363<p>Undefined values are useful because they indicate to the compiler that the
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2364 program is well defined no matter what value is used. This gives the
2365 compiler more freedom to optimize. Here are some examples of (potentially
2366 surprising) transformations that are valid (in pseudo IR):</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2367
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2368
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2369<pre class="doc_code">
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2370 %A = add %X, undef
2371 %B = sub %X, undef
2372 %C = xor %X, undef
2373Safe:
2374 %A = undef
2375 %B = undef
2376 %C = undef
2377</pre>
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2378
2379<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]2380 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]2381
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2382<pre class="doc_code">
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2383 %A = or %X, undef
2384 %B = and %X, undef
2385Safe:
2386 %A = -1
2387 %B = 0
2388Unsafe:
2389 %A = undef
2390 %B = undef
2391</pre>
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2392
2393<p>These logical operations have bits that are not always affected by the input.
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]2394 For example, if <tt>%X</tt> has a zero bit, then the output of the
2395 '<tt>and</tt>' operation will always be a zero for that bit, no matter what
2396 the corresponding bit from the '<tt>undef</tt>' is. As such, it is unsafe to
2397 optimize or assume that the result of the '<tt>and</tt>' is '<tt>undef</tt>'.
2398 However, it is safe to assume that all bits of the '<tt>undef</tt>' could be
2399 0, and optimize the '<tt>and</tt>' to 0. Likewise, it is safe to assume that
2400 all the bits of the '<tt>undef</tt>' operand to the '<tt>or</tt>' could be
2401 set, allowing the '<tt>or</tt>' to be folded to -1.</p>
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2402
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2403<pre class="doc_code">
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2404 %A = select undef, %X, %Y
2405 %B = select undef, 42, %Y
2406 %C = select %X, %Y, undef
2407Safe:
2408 %A = %X (or %Y)
2409 %B = 42 (or %Y)
2410 %C = %Y
2411Unsafe:
2412 %A = undef
2413 %B = undef
2414 %C = undef
2415</pre>
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2416
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]2417<p>This set of examples shows that undefined '<tt>select</tt>' (and conditional
2418 branch) conditions can go <em>either way</em>, but they have to come from one
2419 of the two operands. In the <tt>%A</tt> example, if <tt>%X</tt> and
2420 <tt>%Y</tt> were both known to have a clear low bit, then <tt>%A</tt> would
2421 have to have a cleared low bit. However, in the <tt>%C</tt> example, the
2422 optimizer is allowed to assume that the '<tt>undef</tt>' operand could be the
2423 same as <tt>%Y</tt>, allowing the whole '<tt>select</tt>' to be
2424 eliminated.</p>
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2425
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2426<pre class="doc_code">
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2427 %A = xor undef, undef
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]2428
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2429 %B = undef
2430 %C = xor %B, %B
2431
2432 %D = undef
2433 %E = icmp lt %D, 4
2434 %F = icmp gte %D, 4
2435
2436Safe:
2437 %A = undef
2438 %B = undef
2439 %C = undef
2440 %D = undef
2441 %E = undef
2442 %F = undef
2443</pre>
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2444
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]2445<p>This example points out that two '<tt>undef</tt>' operands are not
2446 necessarily the same. This can be surprising to people (and also matches C
2447 semantics) where they assume that "<tt>X^X</tt>" is always zero, even
2448 if <tt>X</tt> is undefined. This isn't true for a number of reasons, but the
2449 short answer is that an '<tt>undef</tt>' "variable" can arbitrarily change
2450 its value over its "live range". This is true because the variable doesn't
2451 actually <em>have a live range</em>. Instead, the value is logically read
2452 from arbitrary registers that happen to be around when needed, so the value
2453 is not necessarily consistent over time. In fact, <tt>%A</tt> and <tt>%C</tt>
2454 need to have the same semantics or the core LLVM "replace all uses with"
2455 concept would not hold.</p>
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2456
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2457<pre class="doc_code">
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2458 %A = fdiv undef, %X
2459 %B = fdiv %X, undef
2460Safe:
2461 %A = undef
2462b: unreachable
2463</pre>
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2464
2465<p>These examples show the crucial difference between an <em>undefined
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]2466 value</em> and <em>undefined behavior</em>. An undefined value (like
2467 '<tt>undef</tt>') is allowed to have an arbitrary bit-pattern. This means that
2468 the <tt>%A</tt> operation can be constant folded to '<tt>undef</tt>', because
2469 the '<tt>undef</tt>' could be an SNaN, and <tt>fdiv</tt> is not (currently)
2470 defined on SNaN's. However, in the second example, we can make a more
2471 aggressive assumption: because the <tt>undef</tt> is allowed to be an
2472 arbitrary value, we are allowed to assume that it could be zero. Since a
2473 divide by zero has <em>undefined behavior</em>, we are allowed to assume that
2474 the operation does not execute at all. This allows us to delete the divide and
2475 all code after it. Because the undefined operation "can't happen", the
2476 optimizer can assume that it occurs in dead code.</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]2477
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2478<pre class="doc_code">
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2479a: store undef -> %X
2480b: store %X -> undef
2481Safe:
2482a: &lt;deleted&gt;
2483b: unreachable
2484</pre>
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2485
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]2486<p>These examples reiterate the <tt>fdiv</tt> example: a store <em>of</em> an
2487 undefined value can be assumed to not have any effect; we can assume that the
2488 value is overwritten with bits that happen to match what was already there.
2489 However, a store <em>to</em> an undefined location could clobber arbitrary
2490 memory, therefore, it has undefined behavior.</p>
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2491
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2492</div>
2493
2494<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2495<h3>
2496 <a name="trapvalues">Trap Values</a>
2497</h3>
2498
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2499<div>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]2500
Dan Gohmanc68ce062010-04-26 20:21:21 +0000[diff] [blame]2501<p>Trap values are similar to <a href="#undefvalues">undef values</a>, however
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]2502 instead of representing an unspecified bit pattern, they represent the
2503 fact that an instruction or constant expression which cannot evoke side
2504 effects has nevertheless detected a condition which results in undefined
Dan Gohmanc68ce062010-04-26 20:21:21 +0000[diff] [blame]2505 behavior.</p>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]2506
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2507<p>There is currently no way of representing a trap value in the IR; they
Dan Gohman855abed2010-05-03 14:51:43 +0000[diff] [blame]2508 only exist when produced by operations such as
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2509 <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]2510
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2511<p>Trap value behavior is defined in terms of value <i>dependence</i>:</p>
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2512
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2513<ul>
2514<li>Values other than <a href="#i_phi"><tt>phi</tt></a> nodes depend on
2515 their operands.</li>
2516
2517<li><a href="#i_phi"><tt>Phi</tt></a> nodes depend on the operand corresponding
2518 to their dynamic predecessor basic block.</li>
2519
2520<li>Function arguments depend on the corresponding actual argument values in
2521 the dynamic callers of their functions.</li>
2522
2523<li><a href="#i_call"><tt>Call</tt></a> instructions depend on the
2524 <a href="#i_ret"><tt>ret</tt></a> instructions that dynamically transfer
2525 control back to them.</li>
2526
Dan Gohmanb5328162010-05-03 14:55:22 +0000[diff] [blame]2527<li><a href="#i_invoke"><tt>Invoke</tt></a> instructions depend on the
2528 <a href="#i_ret"><tt>ret</tt></a>, <a href="#i_unwind"><tt>unwind</tt></a>,
2529 or exception-throwing call instructions that dynamically transfer control
2530 back to them.</li>
2531
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2532<li>Non-volatile loads and stores depend on the most recent stores to all of the
2533 referenced memory addresses, following the order in the IR
2534 (including loads and stores implied by intrinsics such as
2535 <a href="#int_memcpy"><tt>@llvm.memcpy</tt></a>.)</li>
2536
Dan Gohman7c24ff12010-05-03 14:59:34 +0000[diff] [blame]2537<!-- TODO: In the case of multiple threads, this only applies if the store
2538 "happens-before" the load or store. -->
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2539
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2540<!-- TODO: floating-point exception state -->
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2541
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2542<li>An instruction with externally visible side effects depends on the most
2543 recent preceding instruction with externally visible side effects, following
Dan Gohmanff70fe42010-07-06 15:26:33 +0000[diff] [blame]2544 the order in the IR. (This includes
2545 <a href="#volatile">volatile operations</a>.)</li>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]2546
Dan Gohmanb5328162010-05-03 14:55:22 +0000[diff] [blame]2547<li>An instruction <i>control-depends</i> on a
2548 <a href="#terminators">terminator instruction</a>
2549 if the terminator instruction has multiple successors and the instruction
2550 is always executed when control transfers to one of the successors, and
Chris Lattner7a2bdde2011-04-15 05:18:47 +0000[diff] [blame]2551 may not be executed when control is transferred to another.</li>
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2552
Dan Gohmanca4cac42011-04-12 23:05:59 +0000[diff] [blame]2553<li>Additionally, an instruction also <i>control-depends</i> on a terminator
2554 instruction if the set of instructions it otherwise depends on would be
Chris Lattner7a2bdde2011-04-15 05:18:47 +0000[diff] [blame]2555 different if the terminator had transferred control to a different
Dan Gohmanca4cac42011-04-12 23:05:59 +0000[diff] [blame]2556 successor.</li>
2557
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2558<li>Dependence is transitive.</li>
2559
2560</ul>
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2561
2562<p>Whenever a trap value is generated, all values which depend on it evaluate
2563 to trap. If they have side effects, the evoke their side effects as if each
2564 operand with a trap value were undef. If they have externally-visible side
2565 effects, the behavior is undefined.</p>
2566
2567<p>Here are some examples:</p>
Dan Gohmanc30f6e12010-04-26 20:54:53 +0000[diff] [blame]2568
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2569<pre class="doc_code">
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2570entry:
2571 %trap = sub nuw i32 0, 1 ; Results in a trap value.
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2572 %still_trap = and i32 %trap, 0 ; Whereas (and i32 undef, 0) would return 0.
2573 %trap_yet_again = getelementptr i32* @h, i32 %still_trap
2574 store i32 0, i32* %trap_yet_again ; undefined behavior
2575
2576 store i32 %trap, i32* @g ; Trap value conceptually stored to memory.
2577 %trap2 = load i32* @g ; Returns a trap value, not just undef.
2578
2579 volatile store i32 %trap, i32* @g ; External observation; undefined behavior.
2580
2581 %narrowaddr = bitcast i32* @g to i16*
2582 %wideaddr = bitcast i32* @g to i64*
Nick Lewycky64f9fb12011-05-16 19:29:30 +0000[diff] [blame]2583 %trap3 = load i16* %narrowaddr ; Returns a trap value.
2584 %trap4 = load i64* %wideaddr ; Returns a trap value.
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2585
Nick Lewycky64f9fb12011-05-16 19:29:30 +0000[diff] [blame]2586 %cmp = icmp slt i32 %trap, 0 ; Returns a trap value.
2587 br i1 %cmp, label %true, label %end ; Branch to either destination.
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2588
2589true:
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2590 volatile store i32 0, i32* @g ; This is control-dependent on %cmp, so
2591 ; it has undefined behavior.
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2592 br label %end
2593
2594end:
2595 %p = phi i32 [ 0, %entry ], [ 1, %true ]
2596 ; Both edges into this PHI are
2597 ; control-dependent on %cmp, so this
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2598 ; always results in a trap value.
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2599
Dan Gohmanca4cac42011-04-12 23:05:59 +0000[diff] [blame]2600 volatile store i32 0, i32* @g ; This would depend on the store in %true
2601 ; if %cmp is true, or the store in %entry
2602 ; otherwise, so this is undefined behavior.
2603
Nick Lewycky64f9fb12011-05-16 19:29:30 +0000[diff] [blame]2604 br i1 %cmp, label %second_true, label %second_end
Dan Gohmanca4cac42011-04-12 23:05:59 +0000[diff] [blame]2605 ; The same branch again, but this time the
2606 ; true block doesn't have side effects.
2607
2608second_true:
2609 ; No side effects!
Nick Lewycky64f9fb12011-05-16 19:29:30 +0000[diff] [blame]2610 ret void
Dan Gohmanca4cac42011-04-12 23:05:59 +0000[diff] [blame]2611
2612second_end:
2613 volatile store i32 0, i32* @g ; This time, the instruction always depends
2614 ; on the store in %end. Also, it is
2615 ; control-equivalent to %end, so this is
Nick Lewycky64f9fb12011-05-16 19:29:30 +0000[diff] [blame]2616 ; well-defined (again, ignoring earlier
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2617 ; undefined behavior in this example).
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2618</pre>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]2619
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]2620</div>
2621
2622<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2623<h3>
2624 <a name="blockaddress">Addresses of Basic Blocks</a>
2625</h3>
2626
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2627<div>
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]2628
Chris Lattnercdfc9402009-11-01 01:27:45 +0000[diff] [blame]2629<p><b><tt>blockaddress(@function, %block)</tt></b></p>
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]2630
2631<p>The '<tt>blockaddress</tt>' constant computes the address of the specified
Chris Lattner2dfdf2a2009-10-27 21:49:40 +0000[diff] [blame]2632 basic block in the specified function, and always has an i8* type. Taking
Chris Lattnercdfc9402009-11-01 01:27:45 +0000[diff] [blame]2633 the address of the entry block is illegal.</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]2634
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]2635<p>This value only has defined behavior when used as an operand to the
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]2636 '<a href="#i_indirectbr"><tt>indirectbr</tt></a>' instruction, or for
2637 comparisons against null. Pointer equality tests between labels addresses
2638 results in undefined behavior &mdash; though, again, comparison against null
2639 is ok, and no label is equal to the null pointer. This may be passed around
2640 as an opaque pointer sized value as long as the bits are not inspected. This
2641 allows <tt>ptrtoint</tt> and arithmetic to be performed on these values so
2642 long as the original value is reconstituted before the <tt>indirectbr</tt>
2643 instruction.</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]2644
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]2645<p>Finally, some targets may provide defined semantics when using the value as
2646 the operand to an inline assembly, but that is target specific.</p>
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]2647
2648</div>
2649
2650
2651<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2652<h3>
2653 <a name="constantexprs">Constant Expressions</a>
2654</h3>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2655
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2656<div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2657
2658<p>Constant expressions are used to allow expressions involving other constants
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2659 to be used as constants. Constant expressions may be of
2660 any <a href="#t_firstclass">first class</a> type and may involve any LLVM
2661 operation that does not have side effects (e.g. load and call are not
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]2662 supported). The following is the syntax for constant expressions:</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2663
2664<dl>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2665 <dt><b><tt>trunc (CST to TYPE)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2666 <dd>Truncate a constant to another type. The bit size of CST must be larger
2667 than the bit size of TYPE. Both types must be integers.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2668
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2669 <dt><b><tt>zext (CST to TYPE)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2670 <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]2671 smaller than the bit size of TYPE. Both types must be integers.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2672
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2673 <dt><b><tt>sext (CST to TYPE)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2674 <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]2675 smaller than the bit size of TYPE. Both types must be integers.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2676
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2677 <dt><b><tt>fptrunc (CST to TYPE)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2678 <dd>Truncate a floating point constant to another floating point type. The
2679 size of CST must be larger than the size of TYPE. Both types must be
2680 floating point.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2681
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2682 <dt><b><tt>fpext (CST to TYPE)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2683 <dd>Floating point extend a constant to another type. The size of CST must be
2684 smaller or equal to the size of TYPE. Both types must be floating
2685 point.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2686
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2687 <dt><b><tt>fptoui (CST to TYPE)</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2688 <dd>Convert a floating point constant to the corresponding unsigned integer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2689 constant. TYPE must be a scalar or vector integer type. CST must be of
2690 scalar or vector floating point type. Both CST and TYPE must be scalars,
2691 or vectors of the same number of elements. If the value won't fit in the
2692 integer type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2693
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2694 <dt><b><tt>fptosi (CST to TYPE)</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2695 <dd>Convert a floating point constant to the corresponding signed integer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2696 constant. TYPE must be a scalar or vector integer type. CST must be of
2697 scalar or vector floating point type. Both CST and TYPE must be scalars,
2698 or vectors of the same number of elements. If the value won't fit in the
2699 integer type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2700
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2701 <dt><b><tt>uitofp (CST to TYPE)</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2702 <dd>Convert an unsigned integer constant to the corresponding floating point
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2703 constant. TYPE must be a scalar or vector floating point type. CST must be
2704 of scalar or vector integer type. Both CST and TYPE must be scalars, or
2705 vectors of the same number of elements. If the value won't fit in the
2706 floating point type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2707
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2708 <dt><b><tt>sitofp (CST to TYPE)</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2709 <dd>Convert a signed integer constant to the corresponding floating point
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2710 constant. TYPE must be a scalar or vector floating point type. CST must be
2711 of scalar or vector integer type. Both CST and TYPE must be scalars, or
2712 vectors of the same number of elements. If the value won't fit in the
2713 floating point type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2714
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2715 <dt><b><tt>ptrtoint (CST to TYPE)</tt></b></dt>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]2716 <dd>Convert a pointer typed constant to the corresponding integer constant
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2717 <tt>TYPE</tt> must be an integer type. <tt>CST</tt> must be of pointer
2718 type. The <tt>CST</tt> value is zero extended, truncated, or unchanged to
2719 make it fit in <tt>TYPE</tt>.</dd>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]2720
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2721 <dt><b><tt>inttoptr (CST to TYPE)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2722 <dd>Convert a integer constant to a pointer constant. TYPE must be a pointer
2723 type. CST must be of integer type. The CST value is zero extended,
2724 truncated, or unchanged to make it fit in a pointer size. This one is
2725 <i>really</i> dangerous!</dd>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]2726
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2727 <dt><b><tt>bitcast (CST to TYPE)</tt></b></dt>
Chris Lattner03bbad62009-02-28 18:27:03 +0000[diff] [blame]2728 <dd>Convert a constant, CST, to another TYPE. The constraints of the operands
2729 are the same as those for the <a href="#i_bitcast">bitcast
2730 instruction</a>.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2731
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2732 <dt><b><tt>getelementptr (CSTPTR, IDX0, IDX1, ...)</tt></b></dt>
2733 <dt><b><tt>getelementptr inbounds (CSTPTR, IDX0, IDX1, ...)</tt></b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2734 <dd>Perform the <a href="#i_getelementptr">getelementptr operation</a> on
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2735 constants. As with the <a href="#i_getelementptr">getelementptr</a>
2736 instruction, the index list may have zero or more indexes, which are
2737 required to make sense for the type of "CSTPTR".</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2738
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2739 <dt><b><tt>select (COND, VAL1, VAL2)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2740 <dd>Perform the <a href="#i_select">select operation</a> on constants.</dd>
Reid Spencer01c42592006-12-04 19:23:19 +0000[diff] [blame]2741
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2742 <dt><b><tt>icmp COND (VAL1, VAL2)</tt></b></dt>
Reid Spencer01c42592006-12-04 19:23:19 +0000[diff] [blame]2743 <dd>Performs the <a href="#i_icmp">icmp operation</a> on constants.</dd>
2744
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2745 <dt><b><tt>fcmp COND (VAL1, VAL2)</tt></b></dt>
Reid Spencer01c42592006-12-04 19:23:19 +0000[diff] [blame]2746 <dd>Performs the <a href="#i_fcmp">fcmp operation</a> on constants.</dd>
Robert Bocchino9fbe1452006-01-10 19:31:34 +0000[diff] [blame]2747
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2748 <dt><b><tt>extractelement (VAL, IDX)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2749 <dd>Perform the <a href="#i_extractelement">extractelement operation</a> on
2750 constants.</dd>
Robert Bocchino9fbe1452006-01-10 19:31:34 +0000[diff] [blame]2751
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2752 <dt><b><tt>insertelement (VAL, ELT, IDX)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2753 <dd>Perform the <a href="#i_insertelement">insertelement operation</a> on
2754 constants.</dd>
Chris Lattnerc1989542006-04-08 00:13:41 +0000[diff] [blame]2755
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2756 <dt><b><tt>shufflevector (VEC1, VEC2, IDXMASK)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2757 <dd>Perform the <a href="#i_shufflevector">shufflevector operation</a> on
2758 constants.</dd>
Chris Lattnerc1989542006-04-08 00:13:41 +0000[diff] [blame]2759
Nick Lewycky9e130ce2010-05-29 06:44:15 +0000[diff] [blame]2760 <dt><b><tt>extractvalue (VAL, IDX0, IDX1, ...)</tt></b></dt>
2761 <dd>Perform the <a href="#i_extractvalue">extractvalue operation</a> on
2762 constants. The index list is interpreted in a similar manner as indices in
2763 a '<a href="#i_getelementptr">getelementptr</a>' operation. At least one
2764 index value must be specified.</dd>
2765
2766 <dt><b><tt>insertvalue (VAL, ELT, IDX0, IDX1, ...)</tt></b></dt>
2767 <dd>Perform the <a href="#i_insertvalue">insertvalue operation</a> on
2768 constants. The index list is interpreted in a similar manner as indices in
2769 a '<a href="#i_getelementptr">getelementptr</a>' operation. At least one
2770 index value must be specified.</dd>
2771
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2772 <dt><b><tt>OPCODE (LHS, RHS)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2773 <dd>Perform the specified operation of the LHS and RHS constants. OPCODE may
2774 be any of the <a href="#binaryops">binary</a>
2775 or <a href="#bitwiseops">bitwise binary</a> operations. The constraints
2776 on operands are the same as those for the corresponding instruction
2777 (e.g. no bitwise operations on floating point values are allowed).</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2778</dl>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2779
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2780</div>
Chris Lattner9ee5d222004-03-08 16:49:10 +0000[diff] [blame]2781
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2782</div>
2783
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2784<!-- *********************************************************************** -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2785<h2><a name="othervalues">Other Values</a></h2>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2786<!-- *********************************************************************** -->
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2787<div>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2788<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2789<h3>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2790<a name="inlineasm">Inline Assembler Expressions</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2791</h3>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2792
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2793<div>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2794
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2795<p>LLVM supports inline assembler expressions (as opposed
2796 to <a href="#moduleasm"> Module-Level Inline Assembly</a>) through the use of
2797 a special value. This value represents the inline assembler as a string
2798 (containing the instructions to emit), a list of operand constraints (stored
Dale Johannesen09fed252009-10-13 21:56:55 +0000[diff] [blame]2799 as a string), a flag that indicates whether or not the inline asm
Dale Johannesen8ba2d5b2009-10-21 23:28:00 +0000[diff] [blame]2800 expression has side effects, and a flag indicating whether the function
2801 containing the asm needs to align its stack conservatively. An example
2802 inline assembler expression is:</p>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2803
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2804<pre class="doc_code">
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2805i32 (i32) asm "bswap $0", "=r,r"
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2806</pre>
2807
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2808<p>Inline assembler expressions may <b>only</b> be used as the callee operand of
2809 a <a href="#i_call"><tt>call</tt> instruction</a>. Thus, typically we
2810 have:</p>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2811
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2812<pre class="doc_code">
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2813%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]2814</pre>
2815
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2816<p>Inline asms with side effects not visible in the constraint list must be
2817 marked as having side effects. This is done through the use of the
2818 '<tt>sideeffect</tt>' keyword, like so:</p>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2819
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2820<pre class="doc_code">
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2821call void asm sideeffect "eieio", ""()
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2822</pre>
2823
Dale Johannesen8ba2d5b2009-10-21 23:28:00 +0000[diff] [blame]2824<p>In some cases inline asms will contain code that will not work unless the
2825 stack is aligned in some way, such as calls or SSE instructions on x86,
2826 yet will not contain code that does that alignment within the asm.
2827 The compiler should make conservative assumptions about what the asm might
2828 contain and should generate its usual stack alignment code in the prologue
2829 if the '<tt>alignstack</tt>' keyword is present:</p>
Dale Johannesen09fed252009-10-13 21:56:55 +0000[diff] [blame]2830
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2831<pre class="doc_code">
Dale Johannesen8ba2d5b2009-10-21 23:28:00 +0000[diff] [blame]2832call void asm alignstack "eieio", ""()
Dale Johannesen09fed252009-10-13 21:56:55 +0000[diff] [blame]2833</pre>
Dale Johannesen09fed252009-10-13 21:56:55 +0000[diff] [blame]2834
2835<p>If both keywords appear the '<tt>sideeffect</tt>' keyword must come
2836 first.</p>
2837
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2838<p>TODO: The format of the asm and constraints string still need to be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2839 documented here. Constraints on what can be done (e.g. duplication, moving,
2840 etc need to be documented). This is probably best done by reference to
2841 another document that covers inline asm from a holistic perspective.</p>
Chris Lattnercf9a4152010-04-07 05:38:05 +0000[diff] [blame]2842
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2843<h4>
Chris Lattnercf9a4152010-04-07 05:38:05 +0000[diff] [blame]2844<a name="inlineasm_md">Inline Asm Metadata</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2845</h4>
Chris Lattnercf9a4152010-04-07 05:38:05 +0000[diff] [blame]2846
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2847<div>
Chris Lattnercf9a4152010-04-07 05:38:05 +0000[diff] [blame]2848
2849<p>The call instructions that wrap inline asm nodes may have a "!srcloc" MDNode
Chris Lattnerce1b9ad2010-11-17 08:20:42 +0000[diff] [blame]2850 attached to it that contains a list of constant integers. If present, the
2851 code generator will use the integer as the location cookie value when report
Chris Lattnercf9a4152010-04-07 05:38:05 +0000[diff] [blame]2852 errors through the LLVMContext error reporting mechanisms. This allows a
Dan Gohman1c70c002010-04-28 00:36:01 +0000[diff] [blame]2853 front-end to correlate backend errors that occur with inline asm back to the
Chris Lattnercf9a4152010-04-07 05:38:05 +0000[diff] [blame]2854 source code that produced it. For example:</p>
2855
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2856<pre class="doc_code">
Chris Lattnercf9a4152010-04-07 05:38:05 +0000[diff] [blame]2857call void asm sideeffect "something bad", ""()<b>, !srcloc !42</b>
2858...
2859!42 = !{ i32 1234567 }
2860</pre>
Chris Lattnercf9a4152010-04-07 05:38:05 +0000[diff] [blame]2861
2862<p>It is up to the front-end to make sense of the magic numbers it places in the
Chris Lattnerce1b9ad2010-11-17 08:20:42 +0000[diff] [blame]2863 IR. If the MDNode contains multiple constants, the code generator will use
2864 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]2865
2866</div>
2867
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2868</div>
2869
Chris Lattnere6a5ddd2010-01-15 21:50:19 +0000[diff] [blame]2870<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2871<h3>
2872 <a name="metadata">Metadata Nodes and Metadata Strings</a>
2873</h3>
Chris Lattnere6a5ddd2010-01-15 21:50:19 +0000[diff] [blame]2874
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2875<div>
Chris Lattnere6a5ddd2010-01-15 21:50:19 +0000[diff] [blame]2876
2877<p>LLVM IR allows metadata to be attached to instructions in the program that
2878 can convey extra information about the code to the optimizers and code
2879 generator. One example application of metadata is source-level debug
2880 information. There are two metadata primitives: strings and nodes. All
2881 metadata has the <tt>metadata</tt> type and is identified in syntax by a
2882 preceding exclamation point ('<tt>!</tt>').</p>
2883
2884<p>A metadata string is a string surrounded by double quotes. It can contain
2885 any character by escaping non-printable characters with "\xx" where "xx" is
2886 the two digit hex code. For example: "<tt>!"test\00"</tt>".</p>
2887
2888<p>Metadata nodes are represented with notation similar to structure constants
2889 (a comma separated list of elements, surrounded by braces and preceded by an
2890 exclamation point). For example: "<tt>!{ metadata !"test\00", i32
2891 10}</tt>". Metadata nodes can have any values as their operand.</p>
2892
2893<p>A <a href="#namedmetadatastructure">named metadata</a> is a collection of
2894 metadata nodes, which can be looked up in the module symbol table. For
2895 example: "<tt>!foo = metadata !{!4, !3}</tt>".
2896
Devang Patele1d50cd2010-03-04 23:44:48 +0000[diff] [blame]2897<p>Metadata can be used as function arguments. Here <tt>llvm.dbg.value</tt>
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2898 function is using two metadata arguments.</p>
Devang Patele1d50cd2010-03-04 23:44:48 +0000[diff] [blame]2899
Bill Wendling9ff5de92011-03-02 02:17:11 +0000[diff] [blame]2900<div class="doc_code">
2901<pre>
2902call void @llvm.dbg.value(metadata !24, i64 0, metadata !25)
2903</pre>
2904</div>
Devang Patele1d50cd2010-03-04 23:44:48 +0000[diff] [blame]2905
2906<p>Metadata can be attached with an instruction. Here metadata <tt>!21</tt> is
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2907 attached with <tt>add</tt> instruction using <tt>!dbg</tt> identifier.</p>
Devang Patele1d50cd2010-03-04 23:44:48 +0000[diff] [blame]2908
Bill Wendling9ff5de92011-03-02 02:17:11 +0000[diff] [blame]2909<div class="doc_code">
2910<pre>
2911%indvar.next = add i64 %indvar, 1, !dbg !21
2912</pre>
2913</div>
2914
Chris Lattnere6a5ddd2010-01-15 21:50:19 +0000[diff] [blame]2915</div>
2916
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2917</div>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]2918
2919<!-- *********************************************************************** -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2920<h2>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]2921 <a name="intrinsic_globals">Intrinsic Global Variables</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2922</h2>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]2923<!-- *********************************************************************** -->
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2924<div>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]2925<p>LLVM has a number of "magic" global variables that contain data that affect
2926code generation or other IR semantics. These are documented here. All globals
Chris Lattner401e10c2009-07-20 06:14:25 +0000[diff] [blame]2927of this sort should have a section specified as "<tt>llvm.metadata</tt>". This
2928section and all globals that start with "<tt>llvm.</tt>" are reserved for use
2929by LLVM.</p>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]2930
2931<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2932<h3>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]2933<a name="intg_used">The '<tt>llvm.used</tt>' Global Variable</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2934</h3>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]2935
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2936<div>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]2937
2938<p>The <tt>@llvm.used</tt> global is an array with i8* element type which has <a
2939href="#linkage_appending">appending linkage</a>. This array contains a list of
2940pointers to global variables and functions which may optionally have a pointer
2941cast formed of bitcast or getelementptr. For example, a legal use of it is:</p>
2942
2943<pre>
2944 @X = global i8 4
2945 @Y = global i32 123
2946
2947 @llvm.used = appending global [2 x i8*] [
2948 i8* @X,
2949 i8* bitcast (i32* @Y to i8*)
2950 ], section "llvm.metadata"
2951</pre>
2952
2953<p>If a global variable appears in the <tt>@llvm.used</tt> list, then the
2954compiler, assembler, and linker are required to treat the symbol as if there is
2955a reference to the global that it cannot see. For example, if a variable has
2956internal linkage and no references other than that from the <tt>@llvm.used</tt>
2957list, it cannot be deleted. This is commonly used to represent references from
2958inline asms and other things the compiler cannot "see", and corresponds to
2959"attribute((used))" in GNU C.</p>
2960
2961<p>On some targets, the code generator must emit a directive to the assembler or
2962object file to prevent the assembler and linker from molesting the symbol.</p>
2963
2964</div>
2965
2966<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2967<h3>
2968 <a name="intg_compiler_used">
2969 The '<tt>llvm.compiler.used</tt>' Global Variable
2970 </a>
2971</h3>
Chris Lattner401e10c2009-07-20 06:14:25 +0000[diff] [blame]2972
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2973<div>
Chris Lattner401e10c2009-07-20 06:14:25 +0000[diff] [blame]2974
2975<p>The <tt>@llvm.compiler.used</tt> directive is the same as the
2976<tt>@llvm.used</tt> directive, except that it only prevents the compiler from
2977touching the symbol. On targets that support it, this allows an intelligent
2978linker to optimize references to the symbol without being impeded as it would be
2979by <tt>@llvm.used</tt>.</p>
2980
2981<p>This is a rare construct that should only be used in rare circumstances, and
2982should not be exposed to source languages.</p>
2983
2984</div>
2985
2986<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2987<h3>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]2988<a name="intg_global_ctors">The '<tt>llvm.global_ctors</tt>' Global Variable</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2989</h3>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]2990
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2991<div>
David Chisnalle31e9962010-04-30 19:23:49 +0000[diff] [blame]2992<pre>
2993%0 = type { i32, void ()* }
David Chisnall27195a52010-04-30 19:27:35 +0000[diff] [blame]2994@llvm.global_ctors = appending global [1 x %0] [%0 { i32 65535, void ()* @ctor }]
David Chisnalle31e9962010-04-30 19:23:49 +0000[diff] [blame]2995</pre>
2996<p>The <tt>@llvm.global_ctors</tt> array contains a list of constructor functions and associated priorities. The functions referenced by this array will be called in ascending order of priority (i.e. lowest first) when the module is loaded. The order of functions with the same priority is not defined.
2997</p>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]2998
2999</div>
3000
3001<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3002<h3>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3003<a name="intg_global_dtors">The '<tt>llvm.global_dtors</tt>' Global Variable</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3004</h3>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3005
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3006<div>
David Chisnalle31e9962010-04-30 19:23:49 +0000[diff] [blame]3007<pre>
3008%0 = type { i32, void ()* }
David Chisnall27195a52010-04-30 19:27:35 +0000[diff] [blame]3009@llvm.global_dtors = appending global [1 x %0] [%0 { i32 65535, void ()* @dtor }]
David Chisnalle31e9962010-04-30 19:23:49 +0000[diff] [blame]3010</pre>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3011
David Chisnalle31e9962010-04-30 19:23:49 +0000[diff] [blame]3012<p>The <tt>@llvm.global_dtors</tt> array contains a list of destructor functions and associated priorities. The functions referenced by this array will be called in descending order of priority (i.e. highest first) when the module is loaded. The order of functions with the same priority is not defined.
3013</p>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3014
3015</div>
3016
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3017</div>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3018
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]3019<!-- *********************************************************************** -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3020<h2><a name="instref">Instruction Reference</a></h2>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3021<!-- *********************************************************************** -->
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]3022
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3023<div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]3024
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3025<p>The LLVM instruction set consists of several different classifications of
3026 instructions: <a href="#terminators">terminator
3027 instructions</a>, <a href="#binaryops">binary instructions</a>,
3028 <a href="#bitwiseops">bitwise binary instructions</a>,
3029 <a href="#memoryops">memory instructions</a>, and
3030 <a href="#otherops">other instructions</a>.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]3031
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3032<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3033<h3>
3034 <a name="terminators">Terminator Instructions</a>
3035</h3>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]3036
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3037<div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]3038
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3039<p>As mentioned <a href="#functionstructure">previously</a>, every basic block
3040 in a program ends with a "Terminator" instruction, which indicates which
3041 block should be executed after the current block is finished. These
3042 terminator instructions typically yield a '<tt>void</tt>' value: they produce
3043 control flow, not values (the one exception being the
3044 '<a href="#i_invoke"><tt>invoke</tt></a>' instruction).</p>
3045
Chris Lattner6445ecb2011-08-02 20:29:13 +0000[diff] [blame]3046<p>The terminator instructions are:
3047 '<a href="#i_ret"><tt>ret</tt></a>',
3048 '<a href="#i_br"><tt>br</tt></a>',
3049 '<a href="#i_switch"><tt>switch</tt></a>',
3050 '<a href="#i_indirectbr"><tt>indirectbr</tt></a>',
3051 '<a href="#i_invoke"><tt>invoke</tt></a>',
3052 '<a href="#i_unwind"><tt>unwind</tt></a>',
3053 '<a href="#i_resume"><tt>resume</tt></a>', and
3054 '<a href="#i_unreachable"><tt>unreachable</tt></a>'.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]3055
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3056<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3057<h4>
3058 <a name="i_ret">'<tt>ret</tt>' Instruction</a>
3059</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3060
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3061<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3062
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3063<h5>Syntax:</h5>
Dan Gohmanb1e6b962008-10-04 19:00:07 +0000[diff] [blame]3064<pre>
3065 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]3066 ret void <i>; Return from void function</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3067</pre>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]3068
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3069<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3070<p>The '<tt>ret</tt>' instruction is used to return control flow (and optionally
3071 a value) from a function back to the caller.</p>
3072
3073<p>There are two forms of the '<tt>ret</tt>' instruction: one that returns a
3074 value and then causes control flow, and one that just causes control flow to
3075 occur.</p>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]3076
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3077<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3078<p>The '<tt>ret</tt>' instruction optionally accepts a single argument, the
3079 return value. The type of the return value must be a
3080 '<a href="#t_firstclass">first class</a>' type.</p>
Dan Gohmanb1e6b962008-10-04 19:00:07 +0000[diff] [blame]3081
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3082<p>A function is not <a href="#wellformed">well formed</a> if it it has a
3083 non-void return type and contains a '<tt>ret</tt>' instruction with no return
3084 value or a return value with a type that does not match its type, or if it
3085 has a void return type and contains a '<tt>ret</tt>' instruction with a
3086 return value.</p>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]3087
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3088<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3089<p>When the '<tt>ret</tt>' instruction is executed, control flow returns back to
3090 the calling function's context. If the caller is a
3091 "<a href="#i_call"><tt>call</tt></a>" instruction, execution continues at the
3092 instruction after the call. If the caller was an
3093 "<a href="#i_invoke"><tt>invoke</tt></a>" instruction, execution continues at
3094 the beginning of the "normal" destination block. If the instruction returns
3095 a value, that value shall set the call or invoke instruction's return
3096 value.</p>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]3097
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3098<h5>Example:</h5>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]3099<pre>
3100 ret i32 5 <i>; Return an integer value of 5</i>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]3101 ret void <i>; Return from a void function</i>
Bill Wendling0a4bbbf2009-02-28 22:12:54 +0000[diff] [blame]3102 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]3103</pre>
Dan Gohmanf3e60bd2009-01-12 23:12:39 +0000[diff] [blame]3104
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3105</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3106<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3107<h4>
3108 <a name="i_br">'<tt>br</tt>' Instruction</a>
3109</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3110
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3111<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3112
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3113<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3114<pre>
Bill Wendlingb3aa4712011-07-26 10:41:15 +0000[diff] [blame]3115 br i1 &lt;cond&gt;, label &lt;iftrue&gt;, label &lt;iffalse&gt;
3116 br label &lt;dest&gt; <i>; Unconditional branch</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3117</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3118
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3119<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3120<p>The '<tt>br</tt>' instruction is used to cause control flow to transfer to a
3121 different basic block in the current function. There are two forms of this
3122 instruction, corresponding to a conditional branch and an unconditional
3123 branch.</p>
3124
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3125<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3126<p>The conditional branch form of the '<tt>br</tt>' instruction takes a single
3127 '<tt>i1</tt>' value and two '<tt>label</tt>' values. The unconditional form
3128 of the '<tt>br</tt>' instruction takes a single '<tt>label</tt>' value as a
3129 target.</p>
3130
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3131<h5>Semantics:</h5>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3132<p>Upon execution of a conditional '<tt>br</tt>' instruction, the '<tt>i1</tt>'
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3133 argument is evaluated. If the value is <tt>true</tt>, control flows to the
3134 '<tt>iftrue</tt>' <tt>label</tt> argument. If "cond" is <tt>false</tt>,
3135 control flows to the '<tt>iffalse</tt>' <tt>label</tt> argument.</p>
3136
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3137<h5>Example:</h5>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]3138<pre>
3139Test:
3140 %cond = <a href="#i_icmp">icmp</a> eq i32 %a, %b
3141 br i1 %cond, label %IfEqual, label %IfUnequal
3142IfEqual:
3143 <a href="#i_ret">ret</a> i32 1
3144IfUnequal:
3145 <a href="#i_ret">ret</a> i32 0
3146</pre>
3147
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3148</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3149
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3150<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3151<h4>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3152 <a name="i_switch">'<tt>switch</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3153</h4>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3154
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3155<div>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3156
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3157<h5>Syntax:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3158<pre>
3159 switch &lt;intty&gt; &lt;value&gt;, label &lt;defaultdest&gt; [ &lt;intty&gt; &lt;val&gt;, label &lt;dest&gt; ... ]
3160</pre>
3161
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3162<h5>Overview:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3163<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]3164 several different places. It is a generalization of the '<tt>br</tt>'
3165 instruction, allowing a branch to occur to one of many possible
3166 destinations.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3167
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3168<h5>Arguments:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3169<p>The '<tt>switch</tt>' instruction uses three parameters: an integer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3170 comparison value '<tt>value</tt>', a default '<tt>label</tt>' destination,
3171 and an array of pairs of comparison value constants and '<tt>label</tt>'s.
3172 The table is not allowed to contain duplicate constant entries.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3173
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3174<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3175<p>The <tt>switch</tt> instruction specifies a table of values and
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3176 destinations. When the '<tt>switch</tt>' instruction is executed, this table
3177 is searched for the given value. If the value is found, control flow is
Benjamin Kramer8040cd32009-10-12 14:46:08 +0000[diff] [blame]3178 transferred to the corresponding destination; otherwise, control flow is
3179 transferred to the default destination.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3180
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3181<h5>Implementation:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3182<p>Depending on properties of the target machine and the particular
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3183 <tt>switch</tt> instruction, this instruction may be code generated in
3184 different ways. For example, it could be generated as a series of chained
3185 conditional branches or with a lookup table.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3186
3187<h5>Example:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3188<pre>
3189 <i>; Emulate a conditional br instruction</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3190 %Val = <a href="#i_zext">zext</a> i1 %value to i32
Dan Gohman2a08c532009-01-04 23:44:43 +0000[diff] [blame]3191 switch i32 %Val, label %truedest [ i32 0, label %falsedest ]
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3192
3193 <i>; Emulate an unconditional br instruction</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3194 switch i32 0, label %dest [ ]
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3195
3196 <i>; Implement a jump table:</i>
Dan Gohman2a08c532009-01-04 23:44:43 +0000[diff] [blame]3197 switch i32 %val, label %otherwise [ i32 0, label %onzero
3198 i32 1, label %onone
3199 i32 2, label %ontwo ]
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3200</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3201
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3202</div>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3203
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]3204
3205<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3206<h4>
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]3207 <a name="i_indirectbr">'<tt>indirectbr</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3208</h4>
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]3209
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3210<div>
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]3211
3212<h5>Syntax:</h5>
3213<pre>
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]3214 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]3215</pre>
3216
3217<h5>Overview:</h5>
3218
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]3219<p>The '<tt>indirectbr</tt>' instruction implements an indirect branch to a label
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]3220 within the current function, whose address is specified by
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]3221 "<tt>address</tt>". Address must be derived from a <a
3222 href="#blockaddress">blockaddress</a> constant.</p>
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]3223
3224<h5>Arguments:</h5>
3225
3226<p>The '<tt>address</tt>' argument is the address of the label to jump to. The
3227 rest of the arguments indicate the full set of possible destinations that the
3228 address may point to. Blocks are allowed to occur multiple times in the
3229 destination list, though this isn't particularly useful.</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3230
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]3231<p>This destination list is required so that dataflow analysis has an accurate
3232 understanding of the CFG.</p>
3233
3234<h5>Semantics:</h5>
3235
3236<p>Control transfers to the block specified in the address argument. All
3237 possible destination blocks must be listed in the label list, otherwise this
3238 instruction has undefined behavior. This implies that jumps to labels
3239 defined in other functions have undefined behavior as well.</p>
3240
3241<h5>Implementation:</h5>
3242
3243<p>This is typically implemented with a jump through a register.</p>
3244
3245<h5>Example:</h5>
3246<pre>
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]3247 indirectbr i8* %Addr, [ label %bb1, label %bb2, label %bb3 ]
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]3248</pre>
3249
3250</div>
3251
3252
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3253<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3254<h4>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3255 <a name="i_invoke">'<tt>invoke</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3256</h4>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3257
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3258<div>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3259
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3260<h5>Syntax:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3261<pre>
Devang Patel307e8ab2008-10-07 17:48:33 +0000[diff] [blame]3262 &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]3263 to label &lt;normal label&gt; unwind label &lt;exception label&gt;
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3264</pre>
3265
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]3266<h5>Overview:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3267<p>The '<tt>invoke</tt>' instruction causes control to transfer to a specified
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3268 function, with the possibility of control flow transfer to either the
3269 '<tt>normal</tt>' label or the '<tt>exception</tt>' label. If the callee
3270 function returns with the "<tt><a href="#i_ret">ret</a></tt>" instruction,
3271 control flow will return to the "normal" label. If the callee (or any
3272 indirect callees) returns with the "<a href="#i_unwind"><tt>unwind</tt></a>"
3273 instruction, control is interrupted and continued at the dynamically nearest
3274 "exception" label.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3275
Bill Wendlingf78faf82011-08-02 21:52:38 +0000[diff] [blame]3276<p>The '<tt>exception</tt>' label is a
3277 <i><a href="ExceptionHandling.html#overview">landing pad</a></i> for the
3278 exception. As such, '<tt>exception</tt>' label is required to have the
3279 "<a href="#i_landingpad"><tt>landingpad</tt></a>" instruction, which contains
3280 the information about about the behavior of the program after unwinding
3281 happens, as its first non-PHI instruction. The restrictions on the
3282 "<tt>landingpad</tt>" instruction's tightly couples it to the
3283 "<tt>invoke</tt>" instruction, so that the important information contained
3284 within the "<tt>landingpad</tt>" instruction can't be lost through normal
3285 code motion.</p>
3286
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3287<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3288<p>This instruction requires several arguments:</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3289
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3290<ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3291 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
3292 convention</a> the call should use. If none is specified, the call
3293 defaults to using C calling conventions.</li>
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]3294
3295 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3296 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
3297 '<tt>inreg</tt>' attributes are valid here.</li>
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]3298
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3299 <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]3300 function value being invoked. In most cases, this is a direct function
3301 invocation, but indirect <tt>invoke</tt>s are just as possible, branching
3302 off an arbitrary pointer to function value.</li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3303
3304 <li>'<tt>function ptr val</tt>': An LLVM value containing a pointer to a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3305 function to be invoked. </li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3306
3307 <li>'<tt>function args</tt>': argument list whose types match the function
Chris Lattner0724fbd2010-03-02 06:36:51 +0000[diff] [blame]3308 signature argument types and parameter attributes. All arguments must be
3309 of <a href="#t_firstclass">first class</a> type. If the function
3310 signature indicates the function accepts a variable number of arguments,
3311 the extra arguments can be specified.</li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3312
3313 <li>'<tt>normal label</tt>': the label reached when the called function
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3314 executes a '<tt><a href="#i_ret">ret</a></tt>' instruction. </li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3315
3316 <li>'<tt>exception label</tt>': the label reached when a callee returns with
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3317 the <a href="#i_unwind"><tt>unwind</tt></a> instruction. </li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3318
Devang Patel307e8ab2008-10-07 17:48:33 +0000[diff] [blame]3319 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3320 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
3321 '<tt>readnone</tt>' attributes are valid here.</li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3322</ol>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3323
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3324<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3325<p>This instruction is designed to operate as a standard
3326 '<tt><a href="#i_call">call</a></tt>' instruction in most regards. The
3327 primary difference is that it establishes an association with a label, which
3328 is used by the runtime library to unwind the stack.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3329
3330<p>This instruction is used in languages with destructors to ensure that proper
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3331 cleanup is performed in the case of either a <tt>longjmp</tt> or a thrown
3332 exception. Additionally, this is important for implementation of
3333 '<tt>catch</tt>' clauses in high-level languages that support them.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3334
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3335<p>For the purposes of the SSA form, the definition of the value returned by the
3336 '<tt>invoke</tt>' instruction is deemed to occur on the edge from the current
3337 block to the "normal" label. If the callee unwinds then no return value is
3338 available.</p>
Dan Gohmanf96a4992009-05-22 21:47:08 +0000[diff] [blame]3339
Chris Lattnerdf7a6802010-01-15 18:08:37 +0000[diff] [blame]3340<p>Note that the code generator does not yet completely support unwind, and
3341that the invoke/unwind semantics are likely to change in future versions.</p>
3342
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3343<h5>Example:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3344<pre>
Nick Lewyckyd703f652008-03-16 07:18:12 +0000[diff] [blame]3345 %retval = invoke i32 @Test(i32 15) to label %Continue
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]3346 unwind label %TestCleanup <i>; {i32}:retval set</i>
Nick Lewyckyd703f652008-03-16 07:18:12 +0000[diff] [blame]3347 %retval = invoke <a href="#callingconv">coldcc</a> i32 %Testfnptr(i32 15) to label %Continue
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]3348 unwind label %TestCleanup <i>; {i32}:retval set</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3349</pre>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3350
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3351</div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3352
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]3353<!-- _______________________________________________________________________ -->
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3354
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3355<h4>
3356 <a name="i_unwind">'<tt>unwind</tt>' Instruction</a>
3357</h4>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3358
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3359<div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3360
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]3361<h5>Syntax:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3362<pre>
3363 unwind
3364</pre>
3365
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]3366<h5>Overview:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3367<p>The '<tt>unwind</tt>' instruction unwinds the stack, continuing control flow
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3368 at the first callee in the dynamic call stack which used
3369 an <a href="#i_invoke"><tt>invoke</tt></a> instruction to perform the call.
3370 This is primarily used to implement exception handling.</p>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3371
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]3372<h5>Semantics:</h5>
Chris Lattner72ed2002008-04-19 21:01:16 +0000[diff] [blame]3373<p>The '<tt>unwind</tt>' instruction causes execution of the current function to
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3374 immediately halt. The dynamic call stack is then searched for the
3375 first <a href="#i_invoke"><tt>invoke</tt></a> instruction on the call stack.
3376 Once found, execution continues at the "exceptional" destination block
3377 specified by the <tt>invoke</tt> instruction. If there is no <tt>invoke</tt>
3378 instruction in the dynamic call chain, undefined behavior results.</p>
3379
Chris Lattnerdf7a6802010-01-15 18:08:37 +0000[diff] [blame]3380<p>Note that the code generator does not yet completely support unwind, and
3381that the invoke/unwind semantics are likely to change in future versions.</p>
3382
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3383</div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3384
Bill Wendlingdccc03b2011-07-31 06:30:59 +0000[diff] [blame]3385 <!-- _______________________________________________________________________ -->
3386
3387<h4>
3388 <a name="i_resume">'<tt>resume</tt>' Instruction</a>
3389</h4>
3390
3391<div>
3392
3393<h5>Syntax:</h5>
3394<pre>
3395 resume &lt;type&gt; &lt;value&gt;
3396</pre>
3397
3398<h5>Overview:</h5>
3399<p>The '<tt>resume</tt>' instruction is a terminator instruction that has no
3400 successors.</p>
3401
3402<h5>Arguments:</h5>
Bill Wendlingf78faf82011-08-02 21:52:38 +0000[diff] [blame]3403<p>The '<tt>resume</tt>' instruction requires one argument, which must have the
Bill Wendlinge4ad50b2011-08-03 18:37:32 +0000[diff] [blame]3404 same type as the result of any '<tt>landingpad</tt>' instruction in the same
3405 function.</p>
Bill Wendlingdccc03b2011-07-31 06:30:59 +0000[diff] [blame]3406
3407<h5>Semantics:</h5>
3408<p>The '<tt>resume</tt>' instruction resumes propagation of an existing
3409 (in-flight) exception whose unwinding was interrupted with
Bill Wendlingf78faf82011-08-02 21:52:38 +0000[diff] [blame]3410 a <a href="#i_landingpad"><tt>landingpad</tt></a> instruction.</p>
Bill Wendlingdccc03b2011-07-31 06:30:59 +0000[diff] [blame]3411
3412<h5>Example:</h5>
3413<pre>
Bill Wendlingf78faf82011-08-02 21:52:38 +0000[diff] [blame]3414 resume { i8*, i32 } %exn
Bill Wendlingdccc03b2011-07-31 06:30:59 +0000[diff] [blame]3415</pre>
3416
3417</div>
3418
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3419<!-- _______________________________________________________________________ -->
3420
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3421<h4>
3422 <a name="i_unreachable">'<tt>unreachable</tt>' Instruction</a>
3423</h4>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3424
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3425<div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3426
3427<h5>Syntax:</h5>
3428<pre>
3429 unreachable
3430</pre>
3431
3432<h5>Overview:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3433<p>The '<tt>unreachable</tt>' instruction has no defined semantics. This
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3434 instruction is used to inform the optimizer that a particular portion of the
3435 code is not reachable. This can be used to indicate that the code after a
3436 no-return function cannot be reached, and other facts.</p>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3437
3438<h5>Semantics:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3439<p>The '<tt>unreachable</tt>' instruction has no defined semantics.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3440
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3441</div>
3442
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3443</div>
3444
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3445<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3446<h3>
3447 <a name="binaryops">Binary Operations</a>
3448</h3>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3449
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3450<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3451
3452<p>Binary operators are used to do most of the computation in a program. They
3453 require two operands of the same type, execute an operation on them, and
3454 produce a single value. The operands might represent multiple data, as is
3455 the case with the <a href="#t_vector">vector</a> data type. The result value
3456 has the same type as its operands.</p>
3457
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3458<p>There are several different binary operators:</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3459
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3460<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3461<h4>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3462 <a name="i_add">'<tt>add</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3463</h4>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3464
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3465<div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3466
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3467<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3468<pre>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3469 &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]3470 &lt;result&gt; = add nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3471 &lt;result&gt; = add nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3472 &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]3473</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3474
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3475<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3476<p>The '<tt>add</tt>' instruction returns the sum of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3477
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3478<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3479<p>The two arguments to the '<tt>add</tt>' instruction must
3480 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3481 integer values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3482
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3483<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3484<p>The value produced is the integer sum of the two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3485
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3486<p>If the sum has unsigned overflow, the result returned is the mathematical
3487 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]3488
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3489<p>Because LLVM integers use a two's complement representation, this instruction
3490 is appropriate for both signed and unsigned integers.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3491
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]3492<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3493 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3494 <tt>nsw</tt> keywords are present, the result value of the <tt>add</tt>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]3495 is a <a href="#trapvalues">trap value</a> if unsigned and/or signed overflow,
3496 respectively, occurs.</p>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3497
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3498<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3499<pre>
3500 &lt;result&gt; = add i32 4, %var <i>; yields {i32}:result = 4 + %var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3501</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3502
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3503</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3504
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3505<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3506<h4>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3507 <a name="i_fadd">'<tt>fadd</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3508</h4>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3509
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3510<div>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3511
3512<h5>Syntax:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3513<pre>
3514 &lt;result&gt; = fadd &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3515</pre>
3516
3517<h5>Overview:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3518<p>The '<tt>fadd</tt>' instruction returns the sum of its two operands.</p>
3519
3520<h5>Arguments:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3521<p>The two arguments to the '<tt>fadd</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3522 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3523 floating point values. Both arguments must have identical types.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3524
3525<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3526<p>The value produced is the floating point sum of the two operands.</p>
3527
3528<h5>Example:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3529<pre>
3530 &lt;result&gt; = fadd float 4.0, %var <i>; yields {float}:result = 4.0 + %var</i>
3531</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3532
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3533</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3534
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3535<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3536<h4>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3537 <a name="i_sub">'<tt>sub</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3538</h4>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3539
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3540<div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3541
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3542<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3543<pre>
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]3544 &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]3545 &lt;result&gt; = sub nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3546 &lt;result&gt; = sub nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3547 &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]3548</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3549
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3550<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3551<p>The '<tt>sub</tt>' instruction returns the difference of its two
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3552 operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3553
3554<p>Note that the '<tt>sub</tt>' instruction is used to represent the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3555 '<tt>neg</tt>' instruction present in most other intermediate
3556 representations.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3557
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3558<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3559<p>The two arguments to the '<tt>sub</tt>' instruction must
3560 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3561 integer values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3562
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3563<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3564<p>The value produced is the integer difference of the two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3565
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3566<p>If the difference has unsigned overflow, the result returned is the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3567 mathematical result modulo 2<sup>n</sup>, where n is the bit width of the
3568 result.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3569
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3570<p>Because LLVM integers use a two's complement representation, this instruction
3571 is appropriate for both signed and unsigned integers.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3572
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]3573<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3574 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3575 <tt>nsw</tt> keywords are present, the result value of the <tt>sub</tt>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]3576 is a <a href="#trapvalues">trap value</a> if unsigned and/or signed overflow,
3577 respectively, occurs.</p>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3578
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3579<h5>Example:</h5>
Bill Wendlingaac388b2007-05-29 09:42:13 +0000[diff] [blame]3580<pre>
3581 &lt;result&gt; = sub i32 4, %var <i>; yields {i32}:result = 4 - %var</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3582 &lt;result&gt; = sub i32 0, %val <i>; yields {i32}:result = -%var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3583</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3584
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3585</div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3586
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3587<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3588<h4>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3589 <a name="i_fsub">'<tt>fsub</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3590</h4>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3591
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3592<div>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3593
3594<h5>Syntax:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3595<pre>
3596 &lt;result&gt; = fsub &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3597</pre>
3598
3599<h5>Overview:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3600<p>The '<tt>fsub</tt>' instruction returns the difference of its two
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3601 operands.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3602
3603<p>Note that the '<tt>fsub</tt>' instruction is used to represent the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3604 '<tt>fneg</tt>' instruction present in most other intermediate
3605 representations.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3606
3607<h5>Arguments:</h5>
Bill Wendlingd9fe2982009-07-20 02:32:41 +0000[diff] [blame]3608<p>The two arguments to the '<tt>fsub</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3609 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3610 floating point values. Both arguments must have identical types.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3611
3612<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3613<p>The value produced is the floating point difference of the two operands.</p>
3614
3615<h5>Example:</h5>
3616<pre>
3617 &lt;result&gt; = fsub float 4.0, %var <i>; yields {float}:result = 4.0 - %var</i>
3618 &lt;result&gt; = fsub float -0.0, %val <i>; yields {float}:result = -%var</i>
3619</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3620
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3621</div>
3622
3623<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3624<h4>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3625 <a name="i_mul">'<tt>mul</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3626</h4>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3627
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3628<div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3629
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3630<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3631<pre>
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]3632 &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]3633 &lt;result&gt; = mul nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3634 &lt;result&gt; = mul nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3635 &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]3636</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3637
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3638<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3639<p>The '<tt>mul</tt>' instruction returns the product of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3640
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3641<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3642<p>The two arguments to the '<tt>mul</tt>' instruction must
3643 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3644 integer values. Both arguments must have identical types.</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3645
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3646<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3647<p>The value produced is the integer product of the two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3648
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3649<p>If the result of the multiplication has unsigned overflow, the result
3650 returned is the mathematical result modulo 2<sup>n</sup>, where n is the bit
3651 width of the result.</p>
3652
3653<p>Because LLVM integers use a two's complement representation, and the result
3654 is the same width as the operands, this instruction returns the correct
3655 result for both signed and unsigned integers. If a full product
3656 (e.g. <tt>i32</tt>x<tt>i32</tt>-><tt>i64</tt>) is needed, the operands should
3657 be sign-extended or zero-extended as appropriate to the width of the full
3658 product.</p>
3659
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]3660<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3661 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3662 <tt>nsw</tt> keywords are present, the result value of the <tt>mul</tt>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]3663 is a <a href="#trapvalues">trap value</a> if unsigned and/or signed overflow,
3664 respectively, occurs.</p>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3665
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3666<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3667<pre>
3668 &lt;result&gt; = mul i32 4, %var <i>; yields {i32}:result = 4 * %var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3669</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3670
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3671</div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3672
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3673<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3674<h4>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3675 <a name="i_fmul">'<tt>fmul</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3676</h4>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3677
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3678<div>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3679
3680<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3681<pre>
3682 &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]3683</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3684
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3685<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3686<p>The '<tt>fmul</tt>' instruction returns the product of its two operands.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3687
3688<h5>Arguments:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3689<p>The two arguments to the '<tt>fmul</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3690 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3691 floating point values. Both arguments must have identical types.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3692
3693<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3694<p>The value produced is the floating point product of the two operands.</p>
3695
3696<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3697<pre>
3698 &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]3699</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3700
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3701</div>
3702
3703<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3704<h4>
3705 <a name="i_udiv">'<tt>udiv</tt>' Instruction</a>
3706</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3707
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3708<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3709
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3710<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3711<pre>
Chris Lattner35bda892011-02-06 21:44:57 +0000[diff] [blame]3712 &lt;result&gt; = udiv &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3713 &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]3714</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3715
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3716<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3717<p>The '<tt>udiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3718
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3719<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3720<p>The two arguments to the '<tt>udiv</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3721 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3722 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3723
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3724<h5>Semantics:</h5>
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3725<p>The value produced is the unsigned integer quotient of the two operands.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3726
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3727<p>Note that unsigned integer division and signed integer division are distinct
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3728 operations; for signed integer division, use '<tt>sdiv</tt>'.</p>
3729
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3730<p>Division by zero leads to undefined behavior.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3731
Chris Lattner35bda892011-02-06 21:44:57 +0000[diff] [blame]3732<p>If the <tt>exact</tt> keyword is present, the result value of the
3733 <tt>udiv</tt> is a <a href="#trapvalues">trap value</a> if %op1 is not a
3734 multiple of %op2 (as such, "((a udiv exact b) mul b) == a").</p>
3735
3736
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3737<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3738<pre>
3739 &lt;result&gt; = udiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3740</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3741
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3742</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3743
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3744<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3745<h4>
3746 <a name="i_sdiv">'<tt>sdiv</tt>' Instruction</a>
3747</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3748
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3749<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3750
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3751<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3752<pre>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3753 &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]3754 &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]3755</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3756
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3757<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3758<p>The '<tt>sdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3759
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3760<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3761<p>The two arguments to the '<tt>sdiv</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3762 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3763 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3764
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3765<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3766<p>The value produced is the signed integer quotient of the two operands rounded
3767 towards zero.</p>
3768
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3769<p>Note that signed integer division and unsigned integer division are distinct
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3770 operations; for unsigned integer division, use '<tt>udiv</tt>'.</p>
3771
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3772<p>Division by zero leads to undefined behavior. Overflow also leads to
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3773 undefined behavior; this is a rare case, but can occur, for example, by doing
3774 a 32-bit division of -2147483648 by -1.</p>
3775
Dan Gohman9c5beed2009-07-22 00:04:19 +0000[diff] [blame]3776<p>If the <tt>exact</tt> keyword is present, the result value of the
Dan Gohman27ef9972010-04-23 15:23:32 +0000[diff] [blame]3777 <tt>sdiv</tt> is a <a href="#trapvalues">trap value</a> if the result would
Dan Gohman38da9272010-07-11 00:08:34 +0000[diff] [blame]3778 be rounded.</p>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3779
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3780<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3781<pre>
3782 &lt;result&gt; = sdiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3783</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3784
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3785</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3786
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3787<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3788<h4>
3789 <a name="i_fdiv">'<tt>fdiv</tt>' Instruction</a>
3790</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3791
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3792<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3793
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3794<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3795<pre>
Gabor Greiffb224a22008-08-07 21:46:00 +0000[diff] [blame]3796 &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]3797</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3798
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3799<h5>Overview:</h5>
3800<p>The '<tt>fdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3801
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3802<h5>Arguments:</h5>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]3803<p>The two arguments to the '<tt>fdiv</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3804 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3805 floating point values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3806
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3807<h5>Semantics:</h5>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3808<p>The value produced is the floating point quotient of the two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3809
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3810<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3811<pre>
3812 &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]3813</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3814
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3815</div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3816
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3817<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3818<h4>
3819 <a name="i_urem">'<tt>urem</tt>' Instruction</a>
3820</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3821
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3822<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3823
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3824<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3825<pre>
3826 &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]3827</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3828
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3829<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3830<p>The '<tt>urem</tt>' instruction returns the remainder from the unsigned
3831 division of its two arguments.</p>
3832
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3833<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3834<p>The two arguments to the '<tt>urem</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3835 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3836 values. Both arguments must have identical types.</p>
3837
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3838<h5>Semantics:</h5>
3839<p>This instruction returns the unsigned integer <i>remainder</i> of a division.
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3840 This instruction always performs an unsigned division to get the
3841 remainder.</p>
3842
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3843<p>Note that unsigned integer remainder and signed integer remainder are
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3844 distinct operations; for signed integer remainder, use '<tt>srem</tt>'.</p>
3845
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3846<p>Taking the remainder of a division by zero leads to undefined behavior.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3847
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3848<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3849<pre>
3850 &lt;result&gt; = urem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3851</pre>
3852
3853</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3854
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3855<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3856<h4>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3857 <a name="i_srem">'<tt>srem</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3858</h4>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3859
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3860<div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3861
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3862<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3863<pre>
Gabor Greiffb224a22008-08-07 21:46:00 +0000[diff] [blame]3864 &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]3865</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3866
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3867<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3868<p>The '<tt>srem</tt>' instruction returns the remainder from the signed
3869 division of its two operands. This instruction can also take
3870 <a href="#t_vector">vector</a> versions of the values in which case the
3871 elements must be integers.</p>
Chris Lattnerc7d3ab32008-01-04 04:33:49 +0000[diff] [blame]3872
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3873<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3874<p>The two arguments to the '<tt>srem</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3875 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3876 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3877
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3878<h5>Semantics:</h5>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3879<p>This instruction returns the <i>remainder</i> of a division (where the result
Duncan Sandsdea3a5e2011-03-07 09:12:24 +0000[diff] [blame]3880 is either zero or has the same sign as the dividend, <tt>op1</tt>), not the
3881 <i>modulo</i> operator (where the result is either zero or has the same sign
3882 as the divisor, <tt>op2</tt>) of a value.
3883 For more information about the difference,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3884 see <a href="http://mathforum.org/dr.math/problems/anne.4.28.99.html">The
3885 Math Forum</a>. For a table of how this is implemented in various languages,
3886 please see <a href="http://en.wikipedia.org/wiki/Modulo_operation">
3887 Wikipedia: modulo operation</a>.</p>
3888
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3889<p>Note that signed integer remainder and unsigned integer remainder are
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3890 distinct operations; for unsigned integer remainder, use '<tt>urem</tt>'.</p>
3891
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3892<p>Taking the remainder of a division by zero leads to undefined behavior.
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3893 Overflow also leads to undefined behavior; this is a rare case, but can
3894 occur, for example, by taking the remainder of a 32-bit division of
3895 -2147483648 by -1. (The remainder doesn't actually overflow, but this rule
3896 lets srem be implemented using instructions that return both the result of
3897 the division and the remainder.)</p>
3898
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3899<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3900<pre>
3901 &lt;result&gt; = srem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3902</pre>
3903
3904</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3905
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3906<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3907<h4>
3908 <a name="i_frem">'<tt>frem</tt>' Instruction</a>
3909</h4>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3910
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3911<div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3912
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3913<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3914<pre>
3915 &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]3916</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3917
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3918<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3919<p>The '<tt>frem</tt>' instruction returns the remainder from the division of
3920 its two operands.</p>
3921
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3922<h5>Arguments:</h5>
3923<p>The two arguments to the '<tt>frem</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3924 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3925 floating point values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3926
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3927<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3928<p>This instruction returns the <i>remainder</i> of a division. The remainder
3929 has the same sign as the dividend.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3930
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3931<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3932<pre>
3933 &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]3934</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3935
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3936</div>
Robert Bocchino7b81c752006-02-17 21:18:08 +0000[diff] [blame]3937
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3938</div>
3939
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]3940<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3941<h3>
3942 <a name="bitwiseops">Bitwise Binary Operations</a>
3943</h3>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3944
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3945<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3946
3947<p>Bitwise binary operators are used to do various forms of bit-twiddling in a
3948 program. They are generally very efficient instructions and can commonly be
3949 strength reduced from other instructions. They require two operands of the
3950 same type, execute an operation on them, and produce a single value. The
3951 resulting value is the same type as its operands.</p>
3952
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3953<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3954<h4>
3955 <a name="i_shl">'<tt>shl</tt>' Instruction</a>
3956</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3957
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3958<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3959
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3960<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3961<pre>
Chris Lattnerf067d582011-02-07 16:40:21 +0000[diff] [blame]3962 &lt;result&gt; = shl &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3963 &lt;result&gt; = shl nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3964 &lt;result&gt; = shl nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3965 &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]3966</pre>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3967
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3968<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3969<p>The '<tt>shl</tt>' instruction returns the first operand shifted to the left
3970 a specified number of bits.</p>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3971
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3972<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3973<p>Both arguments to the '<tt>shl</tt>' instruction must be the
3974 same <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3975 integer type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3976
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3977<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3978<p>The value produced is <tt>op1</tt> * 2<sup><tt>op2</tt></sup> mod
3979 2<sup>n</sup>, where <tt>n</tt> is the width of the result. If <tt>op2</tt>
3980 is (statically or dynamically) negative or equal to or larger than the number
3981 of bits in <tt>op1</tt>, the result is undefined. If the arguments are
3982 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
3983 shift amount in <tt>op2</tt>.</p>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3984
Chris Lattnerf067d582011-02-07 16:40:21 +0000[diff] [blame]3985<p>If the <tt>nuw</tt> keyword is present, then the shift produces a
3986 <a href="#trapvalues">trap value</a> if it shifts out any non-zero bits. If
Chris Lattner66298c12011-02-09 16:44:44 +0000[diff] [blame]3987 the <tt>nsw</tt> keyword is present, then the shift produces a
Chris Lattnerf067d582011-02-07 16:40:21 +0000[diff] [blame]3988 <a href="#trapvalues">trap value</a> if it shifts out any bits that disagree
3989 with the resultant sign bit. As such, NUW/NSW have the same semantics as
3990 they would if the shift were expressed as a mul instruction with the same
3991 nsw/nuw bits in (mul %op1, (shl 1, %op2)).</p>
3992
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3993<h5>Example:</h5>
3994<pre>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3995 &lt;result&gt; = shl i32 4, %var <i>; yields {i32}: 4 &lt;&lt; %var</i>
3996 &lt;result&gt; = shl i32 4, 2 <i>; yields {i32}: 16</i>
3997 &lt;result&gt; = shl i32 1, 10 <i>; yields {i32}: 1024</i>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3998 &lt;result&gt; = shl i32 1, 32 <i>; undefined</i>
Mon P Wange9f10152008-12-09 05:46:39 +0000[diff] [blame]3999 &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]4000</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4001
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4002</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4003
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4004<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4005<h4>
4006 <a name="i_lshr">'<tt>lshr</tt>' Instruction</a>
4007</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4008
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4009<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4010
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4011<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4012<pre>
Chris Lattnerf067d582011-02-07 16:40:21 +0000[diff] [blame]4013 &lt;result&gt; = lshr &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
4014 &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]4015</pre>
4016
4017<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4018<p>The '<tt>lshr</tt>' instruction (logical shift right) returns the first
4019 operand shifted to the right a specified number of bits with zero fill.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4020
4021<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4022<p>Both arguments to the '<tt>lshr</tt>' instruction must be the same
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4023 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
4024 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4025
4026<h5>Semantics:</h5>
4027<p>This instruction always performs a logical shift right operation. The most
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4028 significant bits of the result will be filled with zero bits after the shift.
4029 If <tt>op2</tt> is (statically or dynamically) equal to or larger than the
4030 number of bits in <tt>op1</tt>, the result is undefined. If the arguments are
4031 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
4032 shift amount in <tt>op2</tt>.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4033
Chris Lattnerf067d582011-02-07 16:40:21 +0000[diff] [blame]4034<p>If the <tt>exact</tt> keyword is present, the result value of the
4035 <tt>lshr</tt> is a <a href="#trapvalues">trap value</a> if any of the bits
4036 shifted out are non-zero.</p>
4037
4038
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4039<h5>Example:</h5>
4040<pre>
4041 &lt;result&gt; = lshr i32 4, 1 <i>; yields {i32}:result = 2</i>
4042 &lt;result&gt; = lshr i32 4, 2 <i>; yields {i32}:result = 1</i>
4043 &lt;result&gt; = lshr i8 4, 3 <i>; yields {i8}:result = 0</i>
4044 &lt;result&gt; = lshr i8 -2, 1 <i>; yields {i8}:result = 0x7FFFFFFF </i>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]4045 &lt;result&gt; = lshr i32 1, 32 <i>; undefined</i>
Mon P Wange9f10152008-12-09 05:46:39 +0000[diff] [blame]4046 &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]4047</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4048
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4049</div>
4050
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]4051<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4052<h4>
4053 <a name="i_ashr">'<tt>ashr</tt>' Instruction</a>
4054</h4>
4055
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4056<div>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4057
4058<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4059<pre>
Chris Lattnerf067d582011-02-07 16:40:21 +0000[diff] [blame]4060 &lt;result&gt; = ashr &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
4061 &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]4062</pre>
4063
4064<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4065<p>The '<tt>ashr</tt>' instruction (arithmetic shift right) returns the first
4066 operand shifted to the right a specified number of bits with sign
4067 extension.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4068
4069<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4070<p>Both arguments to the '<tt>ashr</tt>' instruction must be the same
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4071 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
4072 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4073
4074<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4075<p>This instruction always performs an arithmetic shift right operation, The
4076 most significant bits of the result will be filled with the sign bit
4077 of <tt>op1</tt>. If <tt>op2</tt> is (statically or dynamically) equal to or
4078 larger than the number of bits in <tt>op1</tt>, the result is undefined. If
4079 the arguments are vectors, each vector element of <tt>op1</tt> is shifted by
4080 the corresponding shift amount in <tt>op2</tt>.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4081
Chris Lattnerf067d582011-02-07 16:40:21 +0000[diff] [blame]4082<p>If the <tt>exact</tt> keyword is present, the result value of the
4083 <tt>ashr</tt> is a <a href="#trapvalues">trap value</a> if any of the bits
4084 shifted out are non-zero.</p>
4085
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4086<h5>Example:</h5>
4087<pre>
4088 &lt;result&gt; = ashr i32 4, 1 <i>; yields {i32}:result = 2</i>
4089 &lt;result&gt; = ashr i32 4, 2 <i>; yields {i32}:result = 1</i>
4090 &lt;result&gt; = ashr i8 4, 3 <i>; yields {i8}:result = 0</i>
4091 &lt;result&gt; = ashr i8 -2, 1 <i>; yields {i8}:result = -1</i>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]4092 &lt;result&gt; = ashr i32 1, 32 <i>; undefined</i>
Mon P Wange9f10152008-12-09 05:46:39 +0000[diff] [blame]4093 &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]4094</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4095
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4096</div>
4097
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4098<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4099<h4>
4100 <a name="i_and">'<tt>and</tt>' Instruction</a>
4101</h4>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4102
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4103<div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4104
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4105<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4106<pre>
Gabor Greiffb224a22008-08-07 21:46:00 +0000[diff] [blame]4107 &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]4108</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4109
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4110<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4111<p>The '<tt>and</tt>' instruction returns the bitwise logical and of its two
4112 operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4113
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4114<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4115<p>The two arguments to the '<tt>and</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4116 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
4117 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4118
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4119<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4120<p>The truth table used for the '<tt>and</tt>' instruction is:</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4121
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4122<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4123 <tbody>
4124 <tr>
4125 <td>In0</td>
4126 <td>In1</td>
4127 <td>Out</td>
4128 </tr>
4129 <tr>
4130 <td>0</td>
4131 <td>0</td>
4132 <td>0</td>
4133 </tr>
4134 <tr>
4135 <td>0</td>
4136 <td>1</td>
4137 <td>0</td>
4138 </tr>
4139 <tr>
4140 <td>1</td>
4141 <td>0</td>
4142 <td>0</td>
4143 </tr>
4144 <tr>
4145 <td>1</td>
4146 <td>1</td>
4147 <td>1</td>
4148 </tr>
4149 </tbody>
4150</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4151
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4152<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4153<pre>
4154 &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]4155 &lt;result&gt; = and i32 15, 40 <i>; yields {i32}:result = 8</i>
4156 &lt;result&gt; = and i32 4, 8 <i>; yields {i32}:result = 0</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4157</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4158</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4159<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4160<h4>
4161 <a name="i_or">'<tt>or</tt>' Instruction</a>
4162</h4>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4163
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4164<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4165
4166<h5>Syntax:</h5>
4167<pre>
4168 &lt;result&gt; = or &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
4169</pre>
4170
4171<h5>Overview:</h5>
4172<p>The '<tt>or</tt>' instruction returns the bitwise logical inclusive or of its
4173 two operands.</p>
4174
4175<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4176<p>The two arguments to the '<tt>or</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4177 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
4178 values. Both arguments must have identical types.</p>
4179
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4180<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4181<p>The truth table used for the '<tt>or</tt>' instruction is:</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4182
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4183<table border="1" cellspacing="0" cellpadding="4">
4184 <tbody>
4185 <tr>
4186 <td>In0</td>
4187 <td>In1</td>
4188 <td>Out</td>
4189 </tr>
4190 <tr>
4191 <td>0</td>
4192 <td>0</td>
4193 <td>0</td>
4194 </tr>
4195 <tr>
4196 <td>0</td>
4197 <td>1</td>
4198 <td>1</td>
4199 </tr>
4200 <tr>
4201 <td>1</td>
4202 <td>0</td>
4203 <td>1</td>
4204 </tr>
4205 <tr>
4206 <td>1</td>
4207 <td>1</td>
4208 <td>1</td>
4209 </tr>
4210 </tbody>
4211</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4212
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4213<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4214<pre>
4215 &lt;result&gt; = or i32 4, %var <i>; yields {i32}:result = 4 | %var</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4216 &lt;result&gt; = or i32 15, 40 <i>; yields {i32}:result = 47</i>
4217 &lt;result&gt; = or i32 4, 8 <i>; yields {i32}:result = 12</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4218</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4219
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4220</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4221
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4222<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4223<h4>
4224 <a name="i_xor">'<tt>xor</tt>' Instruction</a>
4225</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4226
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4227<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4228
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4229<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4230<pre>
4231 &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]4232</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4233
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4234<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4235<p>The '<tt>xor</tt>' instruction returns the bitwise logical exclusive or of
4236 its two operands. The <tt>xor</tt> is used to implement the "one's
4237 complement" operation, which is the "~" operator in C.</p>
4238
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4239<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4240<p>The two arguments to the '<tt>xor</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4241 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
4242 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4243
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4244<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4245<p>The truth table used for the '<tt>xor</tt>' instruction is:</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4246
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4247<table border="1" cellspacing="0" cellpadding="4">
4248 <tbody>
4249 <tr>
4250 <td>In0</td>
4251 <td>In1</td>
4252 <td>Out</td>
4253 </tr>
4254 <tr>
4255 <td>0</td>
4256 <td>0</td>
4257 <td>0</td>
4258 </tr>
4259 <tr>
4260 <td>0</td>
4261 <td>1</td>
4262 <td>1</td>
4263 </tr>
4264 <tr>
4265 <td>1</td>
4266 <td>0</td>
4267 <td>1</td>
4268 </tr>
4269 <tr>
4270 <td>1</td>
4271 <td>1</td>
4272 <td>0</td>
4273 </tr>
4274 </tbody>
4275</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4276
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4277<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4278<pre>
4279 &lt;result&gt; = xor i32 4, %var <i>; yields {i32}:result = 4 ^ %var</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4280 &lt;result&gt; = xor i32 15, 40 <i>; yields {i32}:result = 39</i>
4281 &lt;result&gt; = xor i32 4, 8 <i>; yields {i32}:result = 12</i>
4282 &lt;result&gt; = xor i32 %V, -1 <i>; yields {i32}:result = ~%V</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4283</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4284
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4285</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4286
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4287</div>
4288
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4289<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4290<h3>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4291 <a name="vectorops">Vector Operations</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4292</h3>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4293
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4294<div>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4295
4296<p>LLVM supports several instructions to represent vector operations in a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4297 target-independent manner. These instructions cover the element-access and
4298 vector-specific operations needed to process vectors effectively. While LLVM
4299 does directly support these vector operations, many sophisticated algorithms
4300 will want to use target-specific intrinsics to take full advantage of a
4301 specific target.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4302
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4303<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4304<h4>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4305 <a name="i_extractelement">'<tt>extractelement</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4306</h4>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4307
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4308<div>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4309
4310<h5>Syntax:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4311<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4312 &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]4313</pre>
4314
4315<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4316<p>The '<tt>extractelement</tt>' instruction extracts a single scalar element
4317 from a vector at a specified index.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4318
4319
4320<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4321<p>The first operand of an '<tt>extractelement</tt>' instruction is a value
4322 of <a href="#t_vector">vector</a> type. The second operand is an index
4323 indicating the position from which to extract the element. The index may be
4324 a variable.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4325
4326<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4327<p>The result is a scalar of the same type as the element type of
4328 <tt>val</tt>. Its value is the value at position <tt>idx</tt> of
4329 <tt>val</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
4330 results are undefined.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4331
4332<h5>Example:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4333<pre>
Gabor Greifa5b6f452009-10-28 13:14:50 +0000[diff] [blame]4334 &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]4335</pre>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4336
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4337</div>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4338
4339<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4340<h4>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4341 <a name="i_insertelement">'<tt>insertelement</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4342</h4>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4343
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4344<div>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4345
4346<h5>Syntax:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4347<pre>
Dan Gohmanf3480b92008-05-12 23:38:42 +0000[diff] [blame]4348 &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]4349</pre>
4350
4351<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4352<p>The '<tt>insertelement</tt>' instruction inserts a scalar element into a
4353 vector at a specified index.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4354
4355<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4356<p>The first operand of an '<tt>insertelement</tt>' instruction is a value
4357 of <a href="#t_vector">vector</a> type. The second operand is a scalar value
4358 whose type must equal the element type of the first operand. The third
4359 operand is an index indicating the position at which to insert the value.
4360 The index may be a variable.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4361
4362<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4363<p>The result is a vector of the same type as <tt>val</tt>. Its element values
4364 are those of <tt>val</tt> except at position <tt>idx</tt>, where it gets the
4365 value <tt>elt</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
4366 results are undefined.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4367
4368<h5>Example:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4369<pre>
Gabor Greifa5b6f452009-10-28 13:14:50 +0000[diff] [blame]4370 &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]4371</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4372
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4373</div>
4374
4375<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4376<h4>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4377 <a name="i_shufflevector">'<tt>shufflevector</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4378</h4>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4379
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4380<div>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4381
4382<h5>Syntax:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4383<pre>
Mon P Wangaeb06d22008-11-10 04:46:22 +0000[diff] [blame]4384 &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]4385</pre>
4386
4387<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4388<p>The '<tt>shufflevector</tt>' instruction constructs a permutation of elements
4389 from two input vectors, returning a vector with the same element type as the
4390 input and length that is the same as the shuffle mask.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4391
4392<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4393<p>The first two operands of a '<tt>shufflevector</tt>' instruction are vectors
4394 with types that match each other. The third argument is a shuffle mask whose
4395 element type is always 'i32'. The result of the instruction is a vector
4396 whose length is the same as the shuffle mask and whose element type is the
4397 same as the element type of the first two operands.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4398
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4399<p>The shuffle mask operand is required to be a constant vector with either
4400 constant integer or undef values.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4401
4402<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4403<p>The elements of the two input vectors are numbered from left to right across
4404 both of the vectors. The shuffle mask operand specifies, for each element of
4405 the result vector, which element of the two input vectors the result element
4406 gets. The element selector may be undef (meaning "don't care") and the
4407 second operand may be undef if performing a shuffle from only one vector.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4408
4409<h5>Example:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4410<pre>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4411 &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]4412 &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]4413 &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]4414 &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]4415 &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]4416 &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]4417 &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]4418 &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]4419</pre>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4420
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4421</div>
Tanya Lattner09474292006-04-14 19:24:33 +0000[diff] [blame]4422
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4423</div>
4424
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4425<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4426<h3>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4427 <a name="aggregateops">Aggregate Operations</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4428</h3>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4429
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4430<div>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4431
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4432<p>LLVM supports several instructions for working with
4433 <a href="#t_aggregate">aggregate</a> values.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4434
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4435<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4436<h4>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4437 <a name="i_extractvalue">'<tt>extractvalue</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4438</h4>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4439
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4440<div>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4441
4442<h5>Syntax:</h5>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4443<pre>
4444 &lt;result&gt; = extractvalue &lt;aggregate type&gt; &lt;val&gt;, &lt;idx&gt;{, &lt;idx&gt;}*
4445</pre>
4446
4447<h5>Overview:</h5>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4448<p>The '<tt>extractvalue</tt>' instruction extracts the value of a member field
4449 from an <a href="#t_aggregate">aggregate</a> value.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4450
4451<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4452<p>The first operand of an '<tt>extractvalue</tt>' instruction is a value
Chris Lattner61c70e92010-08-28 04:09:24 +0000[diff] [blame]4453 of <a href="#t_struct">struct</a> or
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4454 <a href="#t_array">array</a> type. The operands are constant indices to
4455 specify which value to extract in a similar manner as indices in a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4456 '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
Frits van Bommel13242892010-12-05 20:54:38 +0000[diff] [blame]4457 <p>The major differences to <tt>getelementptr</tt> indexing are:</p>
4458 <ul>
4459 <li>Since the value being indexed is not a pointer, the first index is
4460 omitted and assumed to be zero.</li>
4461 <li>At least one index must be specified.</li>
4462 <li>Not only struct indices but also array indices must be in
4463 bounds.</li>
4464 </ul>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4465
4466<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4467<p>The result is the value at the position in the aggregate specified by the
4468 index operands.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4469
4470<h5>Example:</h5>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4471<pre>
Gabor Greifa5b6f452009-10-28 13:14:50 +0000[diff] [blame]4472 &lt;result&gt; = extractvalue {i32, float} %agg, 0 <i>; yields i32</i>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4473</pre>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4474
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4475</div>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4476
4477<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4478<h4>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4479 <a name="i_insertvalue">'<tt>insertvalue</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4480</h4>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4481
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4482<div>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4483
4484<h5>Syntax:</h5>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4485<pre>
Bill Wendling194229e2011-07-26 20:42:28 +0000[diff] [blame]4486 &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]4487</pre>
4488
4489<h5>Overview:</h5>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4490<p>The '<tt>insertvalue</tt>' instruction inserts a value into a member field
4491 in an <a href="#t_aggregate">aggregate</a> value.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4492
4493<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4494<p>The first operand of an '<tt>insertvalue</tt>' instruction is a value
Chris Lattner61c70e92010-08-28 04:09:24 +0000[diff] [blame]4495 of <a href="#t_struct">struct</a> or
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4496 <a href="#t_array">array</a> type. The second operand is a first-class
4497 value to insert. The following operands are constant indices indicating
4498 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]4499 '<tt><a href="#i_extractvalue">extractvalue</a></tt>' instruction. The
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4500 value to insert must have the same type as the value identified by the
4501 indices.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4502
4503<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4504<p>The result is an aggregate of the same type as <tt>val</tt>. Its value is
4505 that of <tt>val</tt> except that the value at the position specified by the
4506 indices is that of <tt>elt</tt>.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4507
4508<h5>Example:</h5>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4509<pre>
Chris Lattner8645d1a2011-05-22 07:18:08 +0000[diff] [blame]4510 %agg1 = insertvalue {i32, float} undef, i32 1, 0 <i>; yields {i32 1, float undef}</i>
4511 %agg2 = insertvalue {i32, float} %agg1, float %val, 1 <i>; yields {i32 1, float %val}</i>
4512 %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]4513</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4514
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4515</div>
4516
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4517</div>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4518
4519<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4520<h3>
Chris Lattner884a9702006-08-15 00:45:58 +0000[diff] [blame]4521 <a name="memoryops">Memory Access and Addressing Operations</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4522</h3>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4523
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4524<div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4525
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4526<p>A key design point of an SSA-based representation is how it represents
4527 memory. In LLVM, no memory locations are in SSA form, which makes things
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]4528 very simple. This section describes how to read, write, and allocate
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4529 memory in LLVM.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4530
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4531<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4532<h4>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4533 <a name="i_alloca">'<tt>alloca</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4534</h4>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4535
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4536<div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4537
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4538<h5>Syntax:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4539<pre>
Dan Gohmanf75a7d32010-05-28 01:14:11 +0000[diff] [blame]4540 &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]4541</pre>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4542
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4543<h5>Overview:</h5>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]4544<p>The '<tt>alloca</tt>' instruction allocates memory on the stack frame of the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4545 currently executing function, to be automatically released when this function
4546 returns to its caller. The object is always allocated in the generic address
4547 space (address space zero).</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4548
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4549<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4550<p>The '<tt>alloca</tt>' instruction
4551 allocates <tt>sizeof(&lt;type&gt;)*NumElements</tt> bytes of memory on the
4552 runtime stack, returning a pointer of the appropriate type to the program.
4553 If "NumElements" is specified, it is the number of elements allocated,
4554 otherwise "NumElements" is defaulted to be one. If a constant alignment is
4555 specified, the value result of the allocation is guaranteed to be aligned to
4556 at least that boundary. If not specified, or if zero, the target can choose
4557 to align the allocation on any convenient boundary compatible with the
4558 type.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4559
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4560<p>'<tt>type</tt>' may be any sized type.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4561
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4562<h5>Semantics:</h5>
Bill Wendling871eb0a2009-05-08 20:49:29 +0000[diff] [blame]4563<p>Memory is allocated; a pointer is returned. The operation is undefined if
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4564 there is insufficient stack space for the allocation. '<tt>alloca</tt>'d
4565 memory is automatically released when the function returns. The
4566 '<tt>alloca</tt>' instruction is commonly used to represent automatic
4567 variables that must have an address available. When the function returns
4568 (either with the <tt><a href="#i_ret">ret</a></tt>
4569 or <tt><a href="#i_unwind">unwind</a></tt> instructions), the memory is
4570 reclaimed. Allocating zero bytes is legal, but the result is undefined.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4571
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4572<h5>Example:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4573<pre>
Dan Gohman81e21672009-01-04 23:49:44 +0000[diff] [blame]4574 %ptr = alloca i32 <i>; yields {i32*}:ptr</i>
4575 %ptr = alloca i32, i32 4 <i>; yields {i32*}:ptr</i>
4576 %ptr = alloca i32, i32 4, align 1024 <i>; yields {i32*}:ptr</i>
4577 %ptr = alloca i32, align 1024 <i>; yields {i32*}:ptr</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4578</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4579
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4580</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4581
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4582<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4583<h4>
4584 <a name="i_load">'<tt>load</tt>' Instruction</a>
4585</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4586
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4587<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4588
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4589<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4590<pre>
Eli Friedmanf03bb262011-08-12 22:50:01 +0000[diff] [blame]4591 &lt;result&gt; = load [volatile] &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;][, !nontemporal !&lt;index&gt;]
4592 &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]4593 !&lt;index&gt; = !{ i32 1 }
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4594</pre>
4595
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4596<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4597<p>The '<tt>load</tt>' instruction is used to read from memory.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4598
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4599<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4600<p>The argument to the '<tt>load</tt>' instruction specifies the memory address
4601 from which to load. The pointer must point to
4602 a <a href="#t_firstclass">first class</a> type. If the <tt>load</tt> is
4603 marked as <tt>volatile</tt>, then the optimizer is not allowed to modify the
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]4604 number or order of execution of this <tt>load</tt> with other <a
4605 href="#volatile">volatile operations</a>.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4606
Eli Friedman21006d42011-08-09 23:02:53 +0000[diff] [blame]4607<p>If the <code>load</code> is marked as <code>atomic</code>, it takes an extra
4608 <a href="#ordering">ordering</a> and optional <code>singlethread</code>
4609 argument. The <code>release</code> and <code>acq_rel</code> orderings are
4610 not valid on <code>load</code> instructions. Atomic loads produce <a
4611 href="#memorymodel">defined</a> results when they may see multiple atomic
4612 stores. The type of the pointee must be an integer type whose bit width
4613 is a power of two greater than or equal to eight and less than or equal
4614 to a target-specific size limit. <code>align</code> must be explicitly
4615 specified on atomic loads, and the load has undefined behavior if the
4616 alignment is not set to a value which is at least the size in bytes of
4617 the pointee. <code>!nontemporal</code> does not have any defined semantics
4618 for atomic loads.</p>
4619
Bill Wendling7c78dbb2010-02-25 21:23:24 +0000[diff] [blame]4620<p>The optional constant <tt>align</tt> argument specifies the alignment of the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4621 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]4622 omitted <tt>align</tt> argument means that the operation has the preferential
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4623 alignment for the target. It is the responsibility of the code emitter to
4624 ensure that the alignment information is correct. Overestimating the
Bill Wendling7c78dbb2010-02-25 21:23:24 +0000[diff] [blame]4625 alignment results in undefined behavior. Underestimating the alignment may
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4626 produce less efficient code. An alignment of 1 is always safe.</p>
4627
Bill Wendling7c78dbb2010-02-25 21:23:24 +0000[diff] [blame]4628<p>The optional <tt>!nontemporal</tt> metadata must reference a single
4629 metatadata name &lt;index&gt; corresponding to a metadata node with
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]4630 one <tt>i32</tt> entry of value 1. The existence of
Bill Wendling7c78dbb2010-02-25 21:23:24 +0000[diff] [blame]4631 the <tt>!nontemporal</tt> metatadata on the instruction tells the optimizer
4632 and code generator that this load is not expected to be reused in the cache.
4633 The code generator may select special instructions to save cache bandwidth,
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]4634 such as the <tt>MOVNT</tt> instruction on x86.</p>
David Greene8939b0d2010-02-16 20:50:18 +0000[diff] [blame]4635
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4636<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4637<p>The location of memory pointed to is loaded. If the value being loaded is of
4638 scalar type then the number of bytes read does not exceed the minimum number
4639 of bytes needed to hold all bits of the type. For example, loading an
4640 <tt>i24</tt> reads at most three bytes. When loading a value of a type like
4641 <tt>i20</tt> with a size that is not an integral number of bytes, the result
4642 is undefined if the value was not originally written using a store of the
4643 same type.</p>
4644
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4645<h5>Examples:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4646<pre>
4647 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
4648 <a href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4649 %val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4650</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4651
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4652</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4653
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4654<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4655<h4>
4656 <a name="i_store">'<tt>store</tt>' Instruction</a>
4657</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4658
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4659<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4660
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4661<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4662<pre>
Eli Friedmanf03bb262011-08-12 22:50:01 +0000[diff] [blame]4663 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>
4664 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]4665</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4666
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4667<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4668<p>The '<tt>store</tt>' instruction is used to write to memory.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4669
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4670<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4671<p>There are two arguments to the '<tt>store</tt>' instruction: a value to store
4672 and an address at which to store it. The type of the
4673 '<tt>&lt;pointer&gt;</tt>' operand must be a pointer to
4674 the <a href="#t_firstclass">first class</a> type of the
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]4675 '<tt>&lt;value&gt;</tt>' operand. If the <tt>store</tt> is marked as
4676 <tt>volatile</tt>, then the optimizer is not allowed to modify the number or
4677 order of execution of this <tt>store</tt> with other <a
4678 href="#volatile">volatile operations</a>.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4679
Eli Friedman21006d42011-08-09 23:02:53 +0000[diff] [blame]4680<p>If the <code>store</code> is marked as <code>atomic</code>, it takes an extra
4681 <a href="#ordering">ordering</a> and optional <code>singlethread</code>
4682 argument. The <code>acquire</code> and <code>acq_rel</code> orderings aren't
4683 valid on <code>store</code> instructions. Atomic loads produce <a
4684 href="#memorymodel">defined</a> results when they may see multiple atomic
4685 stores. The type of the pointee must be an integer type whose bit width
4686 is a power of two greater than or equal to eight and less than or equal
4687 to a target-specific size limit. <code>align</code> must be explicitly
4688 specified on atomic stores, and the store has undefined behavior if the
4689 alignment is not set to a value which is at least the size in bytes of
4690 the pointee. <code>!nontemporal</code> does not have any defined semantics
4691 for atomic stores.</p>
4692
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4693<p>The optional constant "align" argument specifies the alignment of the
4694 operation (that is, the alignment of the memory address). A value of 0 or an
4695 omitted "align" argument means that the operation has the preferential
4696 alignment for the target. It is the responsibility of the code emitter to
4697 ensure that the alignment information is correct. Overestimating the
4698 alignment results in an undefined behavior. Underestimating the alignment may
4699 produce less efficient code. An alignment of 1 is always safe.</p>
4700
David Greene8939b0d2010-02-16 20:50:18 +0000[diff] [blame]4701<p>The optional !nontemporal metadata must reference a single metatadata
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]4702 name &lt;index&gt; corresponding to a metadata node with one i32 entry of
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]4703 value 1. The existence of the !nontemporal metatadata on the
David Greene8939b0d2010-02-16 20:50:18 +0000[diff] [blame]4704 instruction tells the optimizer and code generator that this load is
4705 not expected to be reused in the cache. The code generator may
4706 select special instructions to save cache bandwidth, such as the
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]4707 MOVNT instruction on x86.</p>
David Greene8939b0d2010-02-16 20:50:18 +0000[diff] [blame]4708
4709
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4710<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4711<p>The contents of memory are updated to contain '<tt>&lt;value&gt;</tt>' at the
4712 location specified by the '<tt>&lt;pointer&gt;</tt>' operand. If
4713 '<tt>&lt;value&gt;</tt>' is of scalar type then the number of bytes written
4714 does not exceed the minimum number of bytes needed to hold all bits of the
4715 type. For example, storing an <tt>i24</tt> writes at most three bytes. When
4716 writing a value of a type like <tt>i20</tt> with a size that is not an
4717 integral number of bytes, it is unspecified what happens to the extra bits
4718 that do not belong to the type, but they will typically be overwritten.</p>
4719
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4720<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4721<pre>
4722 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Bill Wendling8c6c72d2007-10-22 05:10:05 +0000[diff] [blame]4723 store i32 3, i32* %ptr <i>; yields {void}</i>
4724 %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]4725</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4726
Reid Spencer47ce1792006-11-09 21:15:49 +0000[diff] [blame]4727</div>
4728
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4729<!-- _______________________________________________________________________ -->
NAKAMURA Takumib5bb29c2011-08-12 06:17:17 +0000[diff] [blame]4730<h4>
4731<a name="i_fence">'<tt>fence</tt>' Instruction</a>
4732</h4>
Eli Friedman47f35132011-07-25 23:16:38 +0000[diff] [blame]4733
NAKAMURA Takumib5bb29c2011-08-12 06:17:17 +0000[diff] [blame]4734<div>
Eli Friedman47f35132011-07-25 23:16:38 +0000[diff] [blame]4735
4736<h5>Syntax:</h5>
4737<pre>
4738 fence [singlethread] &lt;ordering&gt; <i>; yields {void}</i>
4739</pre>
4740
4741<h5>Overview:</h5>
4742<p>The '<tt>fence</tt>' instruction is used to introduce happens-before edges
4743between operations.</p>
4744
4745<h5>Arguments:</h5> <p>'<code>fence</code>' instructions take an <a
4746href="#ordering">ordering</a> argument which defines what
4747<i>synchronizes-with</i> edges they add. They can only be given
4748<code>acquire</code>, <code>release</code>, <code>acq_rel</code>, and
4749<code>seq_cst</code> orderings.</p>
4750
4751<h5>Semantics:</h5>
4752<p>A fence <var>A</var> which has (at least) <code>release</code> ordering
4753semantics <i>synchronizes with</i> a fence <var>B</var> with (at least)
4754<code>acquire</code> ordering semantics if and only if there exist atomic
4755operations <var>X</var> and <var>Y</var>, both operating on some atomic object
4756<var>M</var>, such that <var>A</var> is sequenced before <var>X</var>,
4757<var>X</var> modifies <var>M</var> (either directly or through some side effect
4758of a sequence headed by <var>X</var>), <var>Y</var> is sequenced before
4759<var>B</var>, and <var>Y</var> observes <var>M</var>. This provides a
4760<i>happens-before</i> dependency between <var>A</var> and <var>B</var>. Rather
4761than an explicit <code>fence</code>, one (but not both) of the atomic operations
4762<var>X</var> or <var>Y</var> might provide a <code>release</code> or
4763<code>acquire</code> (resp.) ordering constraint and still
4764<i>synchronize-with</i> the explicit <code>fence</code> and establish the
4765<i>happens-before</i> edge.</p>
4766
4767<p>A <code>fence</code> which has <code>seq_cst</code> ordering, in addition to
4768having both <code>acquire</code> and <code>release</code> semantics specified
4769above, participates in the global program order of other <code>seq_cst</code>
4770operations and/or fences.</p>
4771
4772<p>The optional "<a href="#singlethread"><code>singlethread</code></a>" argument
4773specifies that the fence only synchronizes with other fences in the same
4774thread. (This is useful for interacting with signal handlers.)</p>
4775
Eli Friedman47f35132011-07-25 23:16:38 +0000[diff] [blame]4776<h5>Example:</h5>
4777<pre>
4778 fence acquire <i>; yields {void}</i>
4779 fence singlethread seq_cst <i>; yields {void}</i>
4780</pre>
4781
4782</div>
4783
4784<!-- _______________________________________________________________________ -->
NAKAMURA Takumib5bb29c2011-08-12 06:17:17 +0000[diff] [blame]4785<h4>
4786<a name="i_cmpxchg">'<tt>cmpxchg</tt>' Instruction</a>
4787</h4>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]4788
NAKAMURA Takumib5bb29c2011-08-12 06:17:17 +0000[diff] [blame]4789<div>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]4790
4791<h5>Syntax:</h5>
4792<pre>
Eli Friedmanf03bb262011-08-12 22:50:01 +0000[diff] [blame]4793 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]4794</pre>
4795
4796<h5>Overview:</h5>
4797<p>The '<tt>cmpxchg</tt>' instruction is used to atomically modify memory.
4798It loads a value in memory and compares it to a given value. If they are
4799equal, it stores a new value into the memory.</p>
4800
4801<h5>Arguments:</h5>
4802<p>There are three arguments to the '<code>cmpxchg</code>' instruction: an
4803address to operate on, a value to compare to the value currently be at that
4804address, and a new value to place at that address if the compared values are
4805equal. The type of '<var>&lt;cmp&gt;</var>' must be an integer type whose
4806bit width is a power of two greater than or equal to eight and less than
4807or equal to a target-specific size limit. '<var>&lt;cmp&gt;</var>' and
4808'<var>&lt;new&gt;</var>' must have the same type, and the type of
4809'<var>&lt;pointer&gt;</var>' must be a pointer to that type. If the
4810<code>cmpxchg</code> is marked as <code>volatile</code>, then the
4811optimizer is not allowed to modify the number or order of execution
4812of this <code>cmpxchg</code> with other <a href="#volatile">volatile
4813operations</a>.</p>
4814
4815<!-- FIXME: Extend allowed types. -->
4816
4817<p>The <a href="#ordering"><var>ordering</var></a> argument specifies how this
4818<code>cmpxchg</code> synchronizes with other atomic operations.</p>
4819
4820<p>The optional "<code>singlethread</code>" argument declares that the
4821<code>cmpxchg</code> is only atomic with respect to code (usually signal
4822handlers) running in the same thread as the <code>cmpxchg</code>. Otherwise the
4823cmpxchg is atomic with respect to all other code in the system.</p>
4824
4825<p>The pointer passed into cmpxchg must have alignment greater than or equal to
4826the size in memory of the operand.
4827
4828<h5>Semantics:</h5>
4829<p>The contents of memory at the location specified by the
4830'<tt>&lt;pointer&gt;</tt>' operand is read and compared to
4831'<tt>&lt;cmp&gt;</tt>'; if the read value is the equal,
4832'<tt>&lt;new&gt;</tt>' is written. The original value at the location
4833is returned.
4834
4835<p>A successful <code>cmpxchg</code> is a read-modify-write instruction for the
4836purpose of identifying <a href="#release_sequence">release sequences</a>. A
4837failed <code>cmpxchg</code> is equivalent to an atomic load with an ordering
4838parameter determined by dropping any <code>release</code> part of the
4839<code>cmpxchg</code>'s ordering.</p>
4840
4841<!--
4842FIXME: Is compare_exchange_weak() necessary? (Consider after we've done
4843optimization work on ARM.)
4844
4845FIXME: Is a weaker ordering constraint on failure helpful in practice?
4846-->
4847
4848<h5>Example:</h5>
4849<pre>
4850entry:
4851 %orig = atomic <a href="#i_load">load</a> i32* %ptr unordered <i>; yields {i32}</i>
4852 <a href="#i_br">br</a> label %loop
4853
4854loop:
4855 %cmp = <a href="#i_phi">phi</a> i32 [ %orig, %entry ], [%old, %loop]
4856 %squared = <a href="#i_mul">mul</a> i32 %cmp, %cmp
4857 %old = cmpxchg i32* %ptr, i32 %cmp, i32 %squared <i>; yields {i32}</i>
4858 %success = <a href="#i_icmp">icmp</a> eq i32 %cmp, %old
4859 <a href="#i_br">br</a> i1 %success, label %done, label %loop
4860
4861done:
4862 ...
4863</pre>
4864
4865</div>
4866
4867<!-- _______________________________________________________________________ -->
NAKAMURA Takumib5bb29c2011-08-12 06:17:17 +0000[diff] [blame]4868<h4>
4869<a name="i_atomicrmw">'<tt>atomicrmw</tt>' Instruction</a>
4870</h4>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]4871
NAKAMURA Takumib5bb29c2011-08-12 06:17:17 +0000[diff] [blame]4872<div>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]4873
4874<h5>Syntax:</h5>
4875<pre>
Eli Friedmanf03bb262011-08-12 22:50:01 +0000[diff] [blame]4876 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]4877</pre>
4878
4879<h5>Overview:</h5>
4880<p>The '<tt>atomicrmw</tt>' instruction is used to atomically modify memory.</p>
4881
4882<h5>Arguments:</h5>
4883<p>There are three arguments to the '<code>atomicrmw</code>' instruction: an
4884operation to apply, an address whose value to modify, an argument to the
4885operation. The operation must be one of the following keywords:</p>
4886<ul>
4887 <li>xchg</li>
4888 <li>add</li>
4889 <li>sub</li>
4890 <li>and</li>
4891 <li>nand</li>
4892 <li>or</li>
4893 <li>xor</li>
4894 <li>max</li>
4895 <li>min</li>
4896 <li>umax</li>
4897 <li>umin</li>
4898</ul>
4899
4900<p>The type of '<var>&lt;value&gt;</var>' must be an integer type whose
4901bit width is a power of two greater than or equal to eight and less than
4902or equal to a target-specific size limit. The type of the
4903'<code>&lt;pointer&gt;</code>' operand must be a pointer to that type.
4904If the <code>atomicrmw</code> is marked as <code>volatile</code>, then the
4905optimizer is not allowed to modify the number or order of execution of this
4906<code>atomicrmw</code> with other <a href="#volatile">volatile
4907 operations</a>.</p>
4908
4909<!-- FIXME: Extend allowed types. -->
4910
4911<h5>Semantics:</h5>
4912<p>The contents of memory at the location specified by the
4913'<tt>&lt;pointer&gt;</tt>' operand are atomically read, modified, and written
4914back. The original value at the location is returned. The modification is
4915specified by the <var>operation</var> argument:</p>
4916
4917<ul>
4918 <li>xchg: <code>*ptr = val</code></li>
4919 <li>add: <code>*ptr = *ptr + val</code></li>
4920 <li>sub: <code>*ptr = *ptr - val</code></li>
4921 <li>and: <code>*ptr = *ptr &amp; val</code></li>
4922 <li>nand: <code>*ptr = ~(*ptr &amp; val)</code></li>
4923 <li>or: <code>*ptr = *ptr | val</code></li>
4924 <li>xor: <code>*ptr = *ptr ^ val</code></li>
4925 <li>max: <code>*ptr = *ptr &gt; val ? *ptr : val</code> (using a signed comparison)</li>
4926 <li>min: <code>*ptr = *ptr &lt; val ? *ptr : val</code> (using a signed comparison)</li>
4927 <li>umax: <code>*ptr = *ptr &gt; val ? *ptr : val</code> (using an unsigned comparison)</li>
4928 <li>umin: <code>*ptr = *ptr &lt; val ? *ptr : val</code> (using an unsigned comparison)</li>
4929</ul>
4930
4931<h5>Example:</h5>
4932<pre>
4933 %old = atomicrmw add i32* %ptr, i32 1 acquire <i>; yields {i32}</i>
4934</pre>
4935
4936</div>
4937
4938<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4939<h4>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4940 <a name="i_getelementptr">'<tt>getelementptr</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4941</h4>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4942
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4943<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4944
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]4945<h5>Syntax:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4946<pre>
Matthijs Kooijmane49d0bc2008-10-13 13:44:15 +0000[diff] [blame]4947 &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]4948 &lt;result&gt; = getelementptr inbounds &lt;pty&gt;* &lt;ptrval&gt;{, &lt;ty&gt; &lt;idx&gt;}*
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4949</pre>
4950
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]4951<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4952<p>The '<tt>getelementptr</tt>' instruction is used to get the address of a
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4953 subelement of an <a href="#t_aggregate">aggregate</a> data structure.
4954 It performs address calculation only and does not access memory.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4955
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]4956<h5>Arguments:</h5>
Matthijs Kooijmane49d0bc2008-10-13 13:44:15 +0000[diff] [blame]4957<p>The first argument is always a pointer, and forms the basis of the
Chris Lattnerc8eef442009-07-29 06:44:13 +0000[diff] [blame]4958 calculation. The remaining arguments are indices that indicate which of the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4959 elements of the aggregate object are indexed. The interpretation of each
4960 index is dependent on the type being indexed into. The first index always
4961 indexes the pointer value given as the first argument, the second index
4962 indexes a value of the type pointed to (not necessarily the value directly
4963 pointed to, since the first index can be non-zero), etc. The first type
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4964 indexed into must be a pointer value, subsequent types can be arrays,
Chris Lattner61c70e92010-08-28 04:09:24 +0000[diff] [blame]4965 vectors, and structs. Note that subsequent types being indexed into
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4966 can never be pointers, since that would require loading the pointer before
4967 continuing calculation.</p>
Matthijs Kooijmane49d0bc2008-10-13 13:44:15 +0000[diff] [blame]4968
4969<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]4970 When indexing into a (optionally packed) structure, only <tt>i32</tt>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4971 integer <b>constants</b> are allowed. When indexing into an array, pointer
4972 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]4973 constant. These integers are treated as signed values where relevant.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4974
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4975<p>For example, let's consider a C code fragment and how it gets compiled to
4976 LLVM:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4977
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]4978<pre class="doc_code">
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4979struct RT {
4980 char A;
Chris Lattnercabc8462007-05-29 15:43:56 +0000[diff] [blame]4981 int B[10][20];
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4982 char C;
4983};
4984struct ST {
Chris Lattnercabc8462007-05-29 15:43:56 +0000[diff] [blame]4985 int X;
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4986 double Y;
4987 struct RT Z;
4988};
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4989
Chris Lattnercabc8462007-05-29 15:43:56 +0000[diff] [blame]4990int *foo(struct ST *s) {
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4991 return &amp;s[1].Z.B[5][13];
4992}
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4993</pre>
4994
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4995<p>The LLVM code generated by the GCC frontend is:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4996
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]4997<pre class="doc_code">
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]4998%RT = <a href="#namedtypes">type</a> { i8 , [10 x [20 x i32]], i8 }
4999%ST = <a href="#namedtypes">type</a> { i32, double, %RT }
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5000
Dan Gohman4df605b2009-07-25 02:23:48 +0000[diff] [blame]5001define i32* @foo(%ST* %s) {
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]5002entry:
5003 %reg = getelementptr %ST* %s, i32 1, i32 2, i32 1, i32 5, i32 13
5004 ret i32* %reg
5005}
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5006</pre>
5007
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]5008<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5009<p>In the example above, the first index is indexing into the '<tt>%ST*</tt>'
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5010 type, which is a pointer, yielding a '<tt>%ST</tt>' = '<tt>{ i32, double, %RT
5011 }</tt>' type, a structure. The second index indexes into the third element
5012 of the structure, yielding a '<tt>%RT</tt>' = '<tt>{ i8 , [10 x [20 x i32]],
5013 i8 }</tt>' type, another structure. The third index indexes into the second
5014 element of the structure, yielding a '<tt>[10 x [20 x i32]]</tt>' type, an
5015 array. The two dimensions of the array are subscripted into, yielding an
5016 '<tt>i32</tt>' type. The '<tt>getelementptr</tt>' instruction returns a
5017 pointer to this element, thus computing a value of '<tt>i32*</tt>' type.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5018
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5019<p>Note that it is perfectly legal to index partially through a structure,
5020 returning a pointer to an inner element. Because of this, the LLVM code for
5021 the given testcase is equivalent to:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5022
5023<pre>
Dan Gohman4df605b2009-07-25 02:23:48 +0000[diff] [blame]5024 define i32* @foo(%ST* %s) {
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5025 %t1 = getelementptr %ST* %s, i32 1 <i>; yields %ST*:%t1</i>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]5026 %t2 = getelementptr %ST* %t1, i32 0, i32 2 <i>; yields %RT*:%t2</i>
5027 %t3 = getelementptr %RT* %t2, i32 0, i32 1 <i>; yields [10 x [20 x i32]]*:%t3</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5028 %t4 = getelementptr [10 x [20 x i32]]* %t3, i32 0, i32 5 <i>; yields [20 x i32]*:%t4</i>
5029 %t5 = getelementptr [20 x i32]* %t4, i32 0, i32 13 <i>; yields i32*:%t5</i>
5030 ret i32* %t5
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5031 }
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]5032</pre>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]5033
Dan Gohmandd8004d2009-07-27 21:53:46 +0000[diff] [blame]5034<p>If the <tt>inbounds</tt> keyword is present, the result value of the
Dan Gohman27ef9972010-04-23 15:23:32 +0000[diff] [blame]5035 <tt>getelementptr</tt> is a <a href="#trapvalues">trap value</a> if the
5036 base pointer is not an <i>in bounds</i> address of an allocated object,
5037 or if any of the addresses that would be formed by successive addition of
5038 the offsets implied by the indices to the base address with infinitely
Eli Friedman266246c2011-08-12 23:37:55 +0000[diff] [blame]5039 precise signed arithmetic are not an <i>in bounds</i> address of that
5040 allocated object. The <i>in bounds</i> addresses for an allocated object
5041 are all the addresses that point into the object, plus the address one
5042 byte past the end.</p>
Dan Gohmandd8004d2009-07-27 21:53:46 +0000[diff] [blame]5043
5044<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]5045 the base address with silently-wrapping two's complement arithmetic. If the
5046 offsets have a different width from the pointer, they are sign-extended or
5047 truncated to the width of the pointer. The result value of the
5048 <tt>getelementptr</tt> may be outside the object pointed to by the base
5049 pointer. The result value may not necessarily be used to access memory
5050 though, even if it happens to point into allocated storage. See the
5051 <a href="#pointeraliasing">Pointer Aliasing Rules</a> section for more
5052 information.</p>
Dan Gohmandd8004d2009-07-27 21:53:46 +0000[diff] [blame]5053
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5054<p>The getelementptr instruction is often confusing. For some more insight into
5055 how it works, see <a href="GetElementPtr.html">the getelementptr FAQ</a>.</p>
Chris Lattner884a9702006-08-15 00:45:58 +0000[diff] [blame]5056
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]5057<h5>Example:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5058<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5059 <i>; yields [12 x i8]*:aptr</i>
Matthijs Kooijmane49d0bc2008-10-13 13:44:15 +0000[diff] [blame]5060 %aptr = getelementptr {i32, [12 x i8]}* %saptr, i64 0, i32 1
5061 <i>; yields i8*:vptr</i>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]5062 %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]5063 <i>; yields i8*:eptr</i>
5064 %eptr = getelementptr [12 x i8]* %aptr, i64 0, i32 1
Sanjiv Gupta9f805c22009-04-25 07:27:44 +0000[diff] [blame]5065 <i>; yields i32*:iptr</i>
Sanjiv Gupta16ffa802009-04-24 16:38:13 +0000[diff] [blame]5066 %iptr = getelementptr [10 x i32]* @arr, i16 0, i16 0
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5067</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5068
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5069</div>
Reid Spencer47ce1792006-11-09 21:15:49 +0000[diff] [blame]5070
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5071</div>
5072
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]5073<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5074<h3>
5075 <a name="convertops">Conversion Operations</a>
5076</h3>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5077
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5078<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5079
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5080<p>The instructions in this category are the conversion instructions (casting)
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5081 which all take a single operand and a type. They perform various bit
5082 conversions on the operand.</p>
5083
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]5084<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5085<h4>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5086 <a name="i_trunc">'<tt>trunc .. to</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5087</h4>
5088
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5089<div>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5090
5091<h5>Syntax:</h5>
5092<pre>
5093 &lt;result&gt; = trunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
5094</pre>
5095
5096<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5097<p>The '<tt>trunc</tt>' instruction truncates its operand to the
5098 type <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5099
5100<h5>Arguments:</h5>
Nadav Rotem8c20ec52011-02-24 21:01:34 +0000[diff] [blame]5101<p>The '<tt>trunc</tt>' instruction takes a value to trunc, and a type to trunc it to.
5102 Both types must be of <a href="#t_integer">integer</a> types, or vectors
5103 of the same number of integers.
5104 The bit size of the <tt>value</tt> must be larger than
5105 the bit size of the destination type, <tt>ty2</tt>.
5106 Equal sized types are not allowed.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5107
5108<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5109<p>The '<tt>trunc</tt>' instruction truncates the high order bits
5110 in <tt>value</tt> and converts the remaining bits to <tt>ty2</tt>. Since the
5111 source size must be larger than the destination size, <tt>trunc</tt> cannot
5112 be a <i>no-op cast</i>. It will always truncate bits.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5113
5114<h5>Example:</h5>
5115<pre>
Nadav Rotem8c20ec52011-02-24 21:01:34 +0000[diff] [blame]5116 %X = trunc i32 257 to i8 <i>; yields i8:1</i>
5117 %Y = trunc i32 123 to i1 <i>; yields i1:true</i>
5118 %Z = trunc i32 122 to i1 <i>; yields i1:false</i>
5119 %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]5120</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5121
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5122</div>
5123
5124<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5125<h4>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5126 <a name="i_zext">'<tt>zext .. to</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5127</h4>
5128
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5129<div>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5130
5131<h5>Syntax:</h5>
5132<pre>
5133 &lt;result&gt; = zext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
5134</pre>
5135
5136<h5>Overview:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5137<p>The '<tt>zext</tt>' instruction zero extends its operand to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5138 <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5139
5140
5141<h5>Arguments:</h5>
Nadav Rotemed9b9342011-02-20 12:37:50 +0000[diff] [blame]5142<p>The '<tt>zext</tt>' instruction takes a value to cast, and a type to cast it to.
5143 Both types must be of <a href="#t_integer">integer</a> types, or vectors
5144 of the same number of integers.
5145 The bit size of the <tt>value</tt> must be smaller than
5146 the bit size of the destination type,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5147 <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5148
5149<h5>Semantics:</h5>
5150<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]5151 bits until it reaches the size of the destination type, <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5152
Reid Spencerb5929522007-01-12 15:46:11 +0000[diff] [blame]5153<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]5154
5155<h5>Example:</h5>
5156<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5157 %X = zext i32 257 to i64 <i>; yields i64:257</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]5158 %Y = zext i1 true to i32 <i>; yields i32:1</i>
Nadav Rotemed9b9342011-02-20 12:37:50 +0000[diff] [blame]5159 %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]5160</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5161
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5162</div>
5163
5164<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5165<h4>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5166 <a name="i_sext">'<tt>sext .. to</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5167</h4>
5168
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5169<div>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5170
5171<h5>Syntax:</h5>
5172<pre>
5173 &lt;result&gt; = sext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
5174</pre>
5175
5176<h5>Overview:</h5>
5177<p>The '<tt>sext</tt>' sign extends <tt>value</tt> to the type <tt>ty2</tt>.</p>
5178
5179<h5>Arguments:</h5>
Nadav Rotem8c20ec52011-02-24 21:01:34 +0000[diff] [blame]5180<p>The '<tt>sext</tt>' instruction takes a value to cast, and a type to cast it to.
5181 Both types must be of <a href="#t_integer">integer</a> types, or vectors
5182 of the same number of integers.
5183 The bit size of the <tt>value</tt> must be smaller than
5184 the bit size of the destination type,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5185 <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5186
5187<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5188<p>The '<tt>sext</tt>' instruction performs a sign extension by copying the sign
5189 bit (highest order bit) of the <tt>value</tt> until it reaches the bit size
5190 of the type <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5191
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]5192<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]5193
5194<h5>Example:</h5>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5195<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5196 %X = sext i8 -1 to i16 <i>; yields i16 :65535</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]5197 %Y = sext i1 true to i32 <i>; yields i32:-1</i>
Nadav Rotem8c20ec52011-02-24 21:01:34 +0000[diff] [blame]5198 %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]5199</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5200
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5201</div>
5202
5203<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5204<h4>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]5205 <a name="i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5206</h4>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]5207
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5208<div>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]5209
5210<h5>Syntax:</h5>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]5211<pre>
5212 &lt;result&gt; = fptrunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
5213</pre>
5214
5215<h5>Overview:</h5>
5216<p>The '<tt>fptrunc</tt>' instruction truncates <tt>value</tt> to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5217 <tt>ty2</tt>.</p>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]5218
5219<h5>Arguments:</h5>
5220<p>The '<tt>fptrunc</tt>' instruction takes a <a href="#t_floating">floating
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5221 point</a> value to cast and a <a href="#t_floating">floating point</a> type
5222 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]5223 <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]5224 <i>no-op cast</i>.</p>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]5225
5226<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5227<p>The '<tt>fptrunc</tt>' instruction truncates a <tt>value</tt> from a larger
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5228 <a href="#t_floating">floating point</a> type to a smaller
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5229 <a href="#t_floating">floating point</a> type. If the value cannot fit
5230 within the destination type, <tt>ty2</tt>, then the results are
5231 undefined.</p>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]5232
5233<h5>Example:</h5>
5234<pre>
5235 %X = fptrunc double 123.0 to float <i>; yields float:123.0</i>
5236 %Y = fptrunc double 1.0E+300 to float <i>; yields undefined</i>
5237</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5238
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]5239</div>
5240
5241<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5242<h4>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5243 <a name="i_fpext">'<tt>fpext .. to</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5244</h4>
5245
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5246<div>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5247
5248<h5>Syntax:</h5>
5249<pre>
5250 &lt;result&gt; = fpext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
5251</pre>
5252
5253<h5>Overview:</h5>
5254<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]5255 floating point value.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5256
5257<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5258<p>The '<tt>fpext</tt>' instruction takes a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5259 <a href="#t_floating">floating point</a> <tt>value</tt> to cast, and
5260 a <a href="#t_floating">floating point</a> type to cast it to. The source
5261 type must be smaller than the destination type.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5262
5263<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]5264<p>The '<tt>fpext</tt>' instruction extends the <tt>value</tt> from a smaller
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5265 <a href="#t_floating">floating point</a> type to a larger
5266 <a href="#t_floating">floating point</a> type. The <tt>fpext</tt> cannot be
5267 used to make a <i>no-op cast</i> because it always changes bits. Use
5268 <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]5269
5270<h5>Example:</h5>
5271<pre>
Nick Lewycky5bb3ece2011-03-31 18:20:19 +0000[diff] [blame]5272 %X = fpext float 3.125 to double <i>; yields double:3.125000e+00</i>
5273 %Y = fpext double %X to fp128 <i>; yields fp128:0xL00000000000000004000900000000000</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5274</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5275
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5276</div>
5277
5278<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5279<h4>
Reid Spencer24d6da52007-01-21 00:29:26 +0000[diff] [blame]5280 <a name="i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5281</h4>
5282
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5283<div>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5284
5285<h5>Syntax:</h5>
5286<pre>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]5287 &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]5288</pre>
5289
5290<h5>Overview:</h5>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]5291<p>The '<tt>fptoui</tt>' converts a floating point <tt>value</tt> to its
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5292 unsigned integer equivalent of type <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5293
5294<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5295<p>The '<tt>fptoui</tt>' instruction takes a value to cast, which must be a
5296 scalar or vector <a href="#t_floating">floating point</a> value, and a type
5297 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
5298 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
5299 vector integer type with the same number of elements as <tt>ty</tt></p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5300
5301<h5>Semantics:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5302<p>The '<tt>fptoui</tt>' instruction converts its
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5303 <a href="#t_floating">floating point</a> operand into the nearest (rounding
5304 towards zero) unsigned integer value. If the value cannot fit
5305 in <tt>ty2</tt>, the results are undefined.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5306
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5307<h5>Example:</h5>
5308<pre>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]5309 %X = fptoui double 123.0 to i32 <i>; yields i32:123</i>
Chris Lattner88519042007-09-22 03:17:52 +0000[diff] [blame]5310 %Y = fptoui float 1.0E+300 to i1 <i>; yields undefined:1</i>
Gabor Greif6a292012009-10-28 09:21:30 +0000[diff] [blame]5311 %Z = fptoui float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5312</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5313
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5314</div>
5315
5316<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5317<h4>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]5318 <a name="i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5319</h4>
5320
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5321<div>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5322
5323<h5>Syntax:</h5>
5324<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]5325 &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]5326</pre>
5327
5328<h5>Overview:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5329<p>The '<tt>fptosi</tt>' instruction converts
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5330 <a href="#t_floating">floating point</a> <tt>value</tt> to
5331 type <tt>ty2</tt>.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5332
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]5333<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5334<p>The '<tt>fptosi</tt>' instruction takes a value to cast, which must be a
5335 scalar or vector <a href="#t_floating">floating point</a> value, and a type
5336 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
5337 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
5338 vector integer type with the same number of elements as <tt>ty</tt></p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5339
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]5340<h5>Semantics:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5341<p>The '<tt>fptosi</tt>' instruction converts its
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5342 <a href="#t_floating">floating point</a> operand into the nearest (rounding
5343 towards zero) signed integer value. If the value cannot fit in <tt>ty2</tt>,
5344 the results are undefined.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5345
Chris Lattner33ba0d92001-07-09 00:26:23 +0000[diff] [blame]5346<h5>Example:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5347<pre>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]5348 %X = fptosi double -123.0 to i32 <i>; yields i32:-123</i>
Chris Lattner88519042007-09-22 03:17:52 +0000[diff] [blame]5349 %Y = fptosi float 1.0E-247 to i1 <i>; yields undefined:1</i>
Gabor Greif6a292012009-10-28 09:21:30 +0000[diff] [blame]5350 %Z = fptosi float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5351</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5352
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5353</div>
5354
5355<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5356<h4>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]5357 <a name="i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5358</h4>
5359
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5360<div>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5361
5362<h5>Syntax:</h5>
5363<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]5364 &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]5365</pre>
5366
5367<h5>Overview:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]5368<p>The '<tt>uitofp</tt>' instruction regards <tt>value</tt> as an unsigned
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5369 integer and converts that value to the <tt>ty2</tt> type.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5370
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5371<h5>Arguments:</h5>
Nate Begemanb348d182007-11-17 03:58:34 +0000[diff] [blame]5372<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]5373 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
5374 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
5375 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
5376 floating point type with the same number of elements as <tt>ty</tt></p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5377
5378<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]5379<p>The '<tt>uitofp</tt>' instruction interprets its operand as an unsigned
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5380 integer quantity and converts it to the corresponding floating point
5381 value. If the value cannot fit in the floating point value, the results are
5382 undefined.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5383
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5384<h5>Example:</h5>
5385<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5386 %X = uitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]5387 %Y = uitofp i8 -1 to double <i>; yields double:255.0</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5388</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5389
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5390</div>
5391
5392<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5393<h4>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]5394 <a name="i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5395</h4>
5396
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5397<div>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5398
5399<h5>Syntax:</h5>
5400<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]5401 &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]5402</pre>
5403
5404<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5405<p>The '<tt>sitofp</tt>' instruction regards <tt>value</tt> as a signed integer
5406 and converts that value to the <tt>ty2</tt> type.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5407
5408<h5>Arguments:</h5>
Nate Begemanb348d182007-11-17 03:58:34 +0000[diff] [blame]5409<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]5410 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
5411 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
5412 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
5413 floating point type with the same number of elements as <tt>ty</tt></p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5414
5415<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5416<p>The '<tt>sitofp</tt>' instruction interprets its operand as a signed integer
5417 quantity and converts it to the corresponding floating point value. If the
5418 value cannot fit in the floating point value, the results are undefined.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5419
5420<h5>Example:</h5>
5421<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5422 %X = sitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]5423 %Y = sitofp i8 -1 to double <i>; yields double:-1.0</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5424</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5425
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5426</div>
5427
5428<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5429<h4>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]5430 <a name="i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5431</h4>
5432
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5433<div>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]5434
5435<h5>Syntax:</h5>
5436<pre>
5437 &lt;result&gt; = ptrtoint &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
5438</pre>
5439
5440<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5441<p>The '<tt>ptrtoint</tt>' instruction converts the pointer <tt>value</tt> to
5442 the integer type <tt>ty2</tt>.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]5443
5444<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5445<p>The '<tt>ptrtoint</tt>' instruction takes a <tt>value</tt> to cast, which
5446 must be a <a href="#t_pointer">pointer</a> value, and a type to cast it to
5447 <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a> type.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]5448
5449<h5>Semantics:</h5>
5450<p>The '<tt>ptrtoint</tt>' instruction converts <tt>value</tt> to integer type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5451 <tt>ty2</tt> by interpreting the pointer value as an integer and either
5452 truncating or zero extending that value to the size of the integer type. If
5453 <tt>value</tt> is smaller than <tt>ty2</tt> then a zero extension is done. If
5454 <tt>value</tt> is larger than <tt>ty2</tt> then a truncation is done. If they
5455 are the same size, then nothing is done (<i>no-op cast</i>) other than a type
5456 change.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]5457
5458<h5>Example:</h5>
5459<pre>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5460 %X = ptrtoint i32* %X to i8 <i>; yields truncation on 32-bit architecture</i>
5461 %Y = ptrtoint i32* %x to i64 <i>; yields zero extension on 32-bit architecture</i>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]5462</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5463
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]5464</div>
5465
5466<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5467<h4>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]5468 <a name="i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5469</h4>
5470
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5471<div>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]5472
5473<h5>Syntax:</h5>
5474<pre>
5475 &lt;result&gt; = inttoptr &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
5476</pre>
5477
5478<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5479<p>The '<tt>inttoptr</tt>' instruction converts an integer <tt>value</tt> to a
5480 pointer type, <tt>ty2</tt>.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]5481
5482<h5>Arguments:</h5>
Duncan Sands8036ca42007-03-30 12:22:09 +0000[diff] [blame]5483<p>The '<tt>inttoptr</tt>' instruction takes an <a href="#t_integer">integer</a>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5484 value to cast, and a type to cast it to, which must be a
5485 <a href="#t_pointer">pointer</a> type.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]5486
5487<h5>Semantics:</h5>
5488<p>The '<tt>inttoptr</tt>' instruction converts <tt>value</tt> to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5489 <tt>ty2</tt> by applying either a zero extension or a truncation depending on
5490 the size of the integer <tt>value</tt>. If <tt>value</tt> is larger than the
5491 size of a pointer then a truncation is done. If <tt>value</tt> is smaller
5492 than the size of a pointer then a zero extension is done. If they are the
5493 same size, nothing is done (<i>no-op cast</i>).</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]5494
5495<h5>Example:</h5>
5496<pre>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5497 %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]5498 %Y = inttoptr i32 255 to i32* <i>; yields no-op on 32-bit architecture</i>
5499 %Z = inttoptr i64 0 to i32* <i>; yields truncation on 32-bit architecture</i>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]5500</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5501
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]5502</div>
5503
5504<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5505<h4>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]5506 <a name="i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5507</h4>
5508
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5509<div>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5510
5511<h5>Syntax:</h5>
5512<pre>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]5513 &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]5514</pre>
5515
5516<h5>Overview:</h5>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]5517<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5518 <tt>ty2</tt> without changing any bits.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5519
5520<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5521<p>The '<tt>bitcast</tt>' instruction takes a value to cast, which must be a
5522 non-aggregate first class value, and a type to cast it to, which must also be
5523 a non-aggregate <a href="#t_firstclass">first class</a> type. The bit sizes
5524 of <tt>value</tt> and the destination type, <tt>ty2</tt>, must be
5525 identical. If the source type is a pointer, the destination type must also be
5526 a pointer. This instruction supports bitwise conversion of vectors to
5527 integers and to vectors of other types (as long as they have the same
5528 size).</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5529
5530<h5>Semantics:</h5>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]5531<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5532 <tt>ty2</tt>. It is always a <i>no-op cast</i> because no bits change with
5533 this conversion. The conversion is done as if the <tt>value</tt> had been
5534 stored to memory and read back as type <tt>ty2</tt>. Pointer types may only
5535 be converted to other pointer types with this instruction. To convert
5536 pointers to other types, use the <a href="#i_inttoptr">inttoptr</a> or
5537 <a href="#i_ptrtoint">ptrtoint</a> instructions first.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5538
5539<h5>Example:</h5>
5540<pre>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5541 %X = bitcast i8 255 to i8 <i>; yields i8 :-1</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5542 %Y = bitcast i32* %x to sint* <i>; yields sint*:%x</i>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5543 %Z = bitcast &lt;2 x int&gt; %V to i64; <i>; yields i64: %V</i>
Chris Lattner33ba0d92001-07-09 00:26:23 +0000[diff] [blame]5544</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5545
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5546</div>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5547
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5548</div>
5549
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5550<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5551<h3>
5552 <a name="otherops">Other Operations</a>
5553</h3>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5554
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5555<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5556
5557<p>The instructions in this category are the "miscellaneous" instructions, which
5558 defy better classification.</p>
5559
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5560<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5561<h4>
5562 <a name="i_icmp">'<tt>icmp</tt>' Instruction</a>
5563</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5564
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5565<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5566
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5567<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5568<pre>
5569 &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]5570</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5571
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5572<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5573<p>The '<tt>icmp</tt>' instruction returns a boolean value or a vector of
5574 boolean values based on comparison of its two integer, integer vector, or
5575 pointer operands.</p>
5576
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5577<h5>Arguments:</h5>
5578<p>The '<tt>icmp</tt>' instruction takes three operands. The first operand is
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5579 the condition code indicating the kind of comparison to perform. It is not a
5580 value, just a keyword. The possible condition code are:</p>
5581
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5582<ol>
5583 <li><tt>eq</tt>: equal</li>
5584 <li><tt>ne</tt>: not equal </li>
5585 <li><tt>ugt</tt>: unsigned greater than</li>
5586 <li><tt>uge</tt>: unsigned greater or equal</li>
5587 <li><tt>ult</tt>: unsigned less than</li>
5588 <li><tt>ule</tt>: unsigned less or equal</li>
5589 <li><tt>sgt</tt>: signed greater than</li>
5590 <li><tt>sge</tt>: signed greater or equal</li>
5591 <li><tt>slt</tt>: signed less than</li>
5592 <li><tt>sle</tt>: signed less or equal</li>
5593</ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5594
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]5595<p>The remaining two arguments must be <a href="#t_integer">integer</a> or
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5596 <a href="#t_pointer">pointer</a> or integer <a href="#t_vector">vector</a>
5597 typed. They must also be identical types.</p>
5598
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5599<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5600<p>The '<tt>icmp</tt>' compares <tt>op1</tt> and <tt>op2</tt> according to the
5601 condition code given as <tt>cond</tt>. The comparison performed always yields
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]5602 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]5603 result, as follows:</p>
5604
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5605<ol>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5606 <li><tt>eq</tt>: yields <tt>true</tt> if the operands are equal,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5607 <tt>false</tt> otherwise. No sign interpretation is necessary or
5608 performed.</li>
5609
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5610 <li><tt>ne</tt>: yields <tt>true</tt> if the operands are unequal,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5611 <tt>false</tt> otherwise. No sign interpretation is necessary or
5612 performed.</li>
5613
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5614 <li><tt>ugt</tt>: interprets the operands as unsigned values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5615 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
5616
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5617 <li><tt>uge</tt>: interprets the operands as unsigned values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5618 <tt>true</tt> if <tt>op1</tt> is greater than or equal
5619 to <tt>op2</tt>.</li>
5620
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5621 <li><tt>ult</tt>: interprets the operands as unsigned values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5622 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
5623
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5624 <li><tt>ule</tt>: interprets the operands as unsigned values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5625 <tt>true</tt> if <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
5626
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5627 <li><tt>sgt</tt>: interprets the operands as signed values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5628 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
5629
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5630 <li><tt>sge</tt>: interprets the operands as signed values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5631 <tt>true</tt> if <tt>op1</tt> is greater than or equal
5632 to <tt>op2</tt>.</li>
5633
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5634 <li><tt>slt</tt>: interprets the operands as signed values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5635 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
5636
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5637 <li><tt>sle</tt>: interprets the operands as signed values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5638 <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]5639</ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5640
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5641<p>If the operands are <a href="#t_pointer">pointer</a> typed, the pointer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5642 values are compared as if they were integers.</p>
5643
5644<p>If the operands are integer vectors, then they are compared element by
5645 element. The result is an <tt>i1</tt> vector with the same number of elements
5646 as the values being compared. Otherwise, the result is an <tt>i1</tt>.</p>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5647
5648<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5649<pre>
5650 &lt;result&gt; = icmp eq i32 4, 5 <i>; yields: result=false</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5651 &lt;result&gt; = icmp ne float* %X, %X <i>; yields: result=false</i>
5652 &lt;result&gt; = icmp ult i16 4, 5 <i>; yields: result=true</i>
5653 &lt;result&gt; = icmp sgt i16 4, 5 <i>; yields: result=false</i>
5654 &lt;result&gt; = icmp ule i16 -4, 5 <i>; yields: result=false</i>
5655 &lt;result&gt; = icmp sge i16 4, 5 <i>; yields: result=false</i>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5656</pre>
Dan Gohmanc766f722009-01-22 01:39:38 +0000[diff] [blame]5657
5658<p>Note that the code generator does not yet support vector types with
5659 the <tt>icmp</tt> instruction.</p>
5660
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5661</div>
5662
5663<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5664<h4>
5665 <a name="i_fcmp">'<tt>fcmp</tt>' Instruction</a>
5666</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5667
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5668<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5669
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5670<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5671<pre>
5672 &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]5673</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5674
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5675<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5676<p>The '<tt>fcmp</tt>' instruction returns a boolean value or vector of boolean
5677 values based on comparison of its operands.</p>
5678
5679<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]5680(<a href="#t_integer"><tt>i1</tt></a>).</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5681
5682<p>If the operands are floating point vectors, then the result type is a vector
5683 of boolean with the same number of elements as the operands being
5684 compared.</p>
5685
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5686<h5>Arguments:</h5>
5687<p>The '<tt>fcmp</tt>' instruction takes three operands. The first operand is
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5688 the condition code indicating the kind of comparison to perform. It is not a
5689 value, just a keyword. The possible condition code are:</p>
5690
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5691<ol>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]5692 <li><tt>false</tt>: no comparison, always returns false</li>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5693 <li><tt>oeq</tt>: ordered and equal</li>
5694 <li><tt>ogt</tt>: ordered and greater than </li>
5695 <li><tt>oge</tt>: ordered and greater than or equal</li>
5696 <li><tt>olt</tt>: ordered and less than </li>
5697 <li><tt>ole</tt>: ordered and less than or equal</li>
5698 <li><tt>one</tt>: ordered and not equal</li>
5699 <li><tt>ord</tt>: ordered (no nans)</li>
5700 <li><tt>ueq</tt>: unordered or equal</li>
5701 <li><tt>ugt</tt>: unordered or greater than </li>
5702 <li><tt>uge</tt>: unordered or greater than or equal</li>
5703 <li><tt>ult</tt>: unordered or less than </li>
5704 <li><tt>ule</tt>: unordered or less than or equal</li>
5705 <li><tt>une</tt>: unordered or not equal</li>
5706 <li><tt>uno</tt>: unordered (either nans)</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]5707 <li><tt>true</tt>: no comparison, always returns true</li>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5708</ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5709
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5710<p><i>Ordered</i> means that neither operand is a QNAN while
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5711 <i>unordered</i> means that either operand may be a QNAN.</p>
5712
5713<p>Each of <tt>val1</tt> and <tt>val2</tt> arguments must be either
5714 a <a href="#t_floating">floating point</a> type or
5715 a <a href="#t_vector">vector</a> of floating point type. They must have
5716 identical types.</p>
5717
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5718<h5>Semantics:</h5>
Gabor Greiffb224a22008-08-07 21:46:00 +0000[diff] [blame]5719<p>The '<tt>fcmp</tt>' instruction compares <tt>op1</tt> and <tt>op2</tt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5720 according to the condition code given as <tt>cond</tt>. If the operands are
5721 vectors, then the vectors are compared element by element. Each comparison
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]5722 performed always yields an <a href="#t_integer">i1</a> result, as
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5723 follows:</p>
5724
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5725<ol>
5726 <li><tt>false</tt>: always yields <tt>false</tt>, regardless of operands.</li>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5727
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5728 <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]5729 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
5730
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]5731 <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]5732 <tt>op1</tt> is greater than <tt>op2</tt>.</li>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5733
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5734 <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]5735 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
5736
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5737 <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]5738 <tt>op1</tt> is less than <tt>op2</tt>.</li>
5739
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5740 <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]5741 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
5742
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5743 <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]5744 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
5745
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]5746 <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]5747
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5748 <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]5749 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
5750
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5751 <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]5752 <tt>op1</tt> is greater than <tt>op2</tt>.</li>
5753
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5754 <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]5755 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
5756
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5757 <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]5758 <tt>op1</tt> is less than <tt>op2</tt>.</li>
5759
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5760 <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]5761 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
5762
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5763 <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]5764 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
5765
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]5766 <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]5767
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5768 <li><tt>true</tt>: always yields <tt>true</tt>, regardless of operands.</li>
5769</ol>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5770
5771<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5772<pre>
5773 &lt;result&gt; = fcmp oeq float 4.0, 5.0 <i>; yields: result=false</i>
Dan Gohmanf72fb672008-09-09 01:02:47 +0000[diff] [blame]5774 &lt;result&gt; = fcmp one float 4.0, 5.0 <i>; yields: result=true</i>
5775 &lt;result&gt; = fcmp olt float 4.0, 5.0 <i>; yields: result=true</i>
5776 &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]5777</pre>
Dan Gohmanc766f722009-01-22 01:39:38 +0000[diff] [blame]5778
5779<p>Note that the code generator does not yet support vector types with
5780 the <tt>fcmp</tt> instruction.</p>
5781
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5782</div>
5783
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5784<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5785<h4>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5786 <a name="i_phi">'<tt>phi</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5787</h4>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5788
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5789<div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5790
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5791<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5792<pre>
5793 &lt;result&gt; = phi &lt;ty&gt; [ &lt;val0&gt;, &lt;label0&gt;], ...
5794</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5795
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5796<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5797<p>The '<tt>phi</tt>' instruction is used to implement the &#966; node in the
5798 SSA graph representing the function.</p>
5799
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5800<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5801<p>The type of the incoming values is specified with the first type field. After
5802 this, the '<tt>phi</tt>' instruction takes a list of pairs as arguments, with
5803 one pair for each predecessor basic block of the current block. Only values
5804 of <a href="#t_firstclass">first class</a> type may be used as the value
5805 arguments to the PHI node. Only labels may be used as the label
5806 arguments.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5807
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5808<p>There must be no non-phi instructions between the start of a basic block and
5809 the PHI instructions: i.e. PHI instructions must be first in a basic
5810 block.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5811
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5812<p>For the purposes of the SSA form, the use of each incoming value is deemed to
5813 occur on the edge from the corresponding predecessor block to the current
5814 block (but after any definition of an '<tt>invoke</tt>' instruction's return
5815 value on the same edge).</p>
Jay Foadd2449092009-06-03 10:20:10 +0000[diff] [blame]5816
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5817<h5>Semantics:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5818<p>At runtime, the '<tt>phi</tt>' instruction logically takes on the value
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5819 specified by the pair corresponding to the predecessor basic block that
5820 executed just prior to the current block.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5821
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5822<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5823<pre>
5824Loop: ; Infinite loop that counts from 0 on up...
5825 %indvar = phi i32 [ 0, %LoopHeader ], [ %nextindvar, %Loop ]
5826 %nextindvar = add i32 %indvar, 1
5827 br label %Loop
5828</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5829
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5830</div>
5831
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5832<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5833<h4>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5834 <a name="i_select">'<tt>select</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5835</h4>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5836
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5837<div>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5838
5839<h5>Syntax:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5840<pre>
Dan Gohmanf72fb672008-09-09 01:02:47 +0000[diff] [blame]5841 &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>
5842
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]5843 <i>selty</i> is either i1 or {&lt;N x i1&gt;}
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5844</pre>
5845
5846<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5847<p>The '<tt>select</tt>' instruction is used to choose one value based on a
5848 condition, without branching.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5849
5850
5851<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5852<p>The '<tt>select</tt>' instruction requires an 'i1' value or a vector of 'i1'
5853 values indicating the condition, and two values of the
5854 same <a href="#t_firstclass">first class</a> type. If the val1/val2 are
5855 vectors and the condition is a scalar, then entire vectors are selected, not
5856 individual elements.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5857
5858<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5859<p>If the condition is an i1 and it evaluates to 1, the instruction returns the
5860 first value argument; otherwise, it returns the second value argument.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5861
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5862<p>If the condition is a vector of i1, then the value arguments must be vectors
5863 of the same size, and the selection is done element by element.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5864
5865<h5>Example:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5866<pre>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]5867 %X = select i1 true, i8 17, i8 42 <i>; yields i8:17</i>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5868</pre>
Dan Gohmanc766f722009-01-22 01:39:38 +0000[diff] [blame]5869
5870<p>Note that the code generator does not yet support conditions
5871 with vector type.</p>
5872
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5873</div>
5874
Robert Bocchino05ccd702006-01-15 20:48:27 +0000[diff] [blame]5875<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5876<h4>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5877 <a name="i_call">'<tt>call</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5878</h4>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5879
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5880<div>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5881
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]5882<h5>Syntax:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5883<pre>
Devang Patel307e8ab2008-10-07 17:48:33 +0000[diff] [blame]5884 &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]5885</pre>
5886
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]5887<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5888<p>The '<tt>call</tt>' instruction represents a simple function call.</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5889
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]5890<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5891<p>This instruction requires several arguments:</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5892
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]5893<ol>
Jeffrey Yasskin95fa80a2010-01-09 19:44:16 +0000[diff] [blame]5894 <li>The optional "tail" marker indicates that the callee function does not
5895 access any allocas or varargs in the caller. Note that calls may be
5896 marked "tail" even if they do not occur before
5897 a <a href="#i_ret"><tt>ret</tt></a> instruction. If the "tail" marker is
5898 present, the function call is eligible for tail call optimization,
5899 but <a href="CodeGenerator.html#tailcallopt">might not in fact be
Evan Chengdc444e92010-03-08 21:05:02 +0000[diff] [blame]5900 optimized into a jump</a>. The code generator may optimize calls marked
5901 "tail" with either 1) automatic <a href="CodeGenerator.html#sibcallopt">
5902 sibling call optimization</a> when the caller and callee have
5903 matching signatures, or 2) forced tail call optimization when the
5904 following extra requirements are met:
Jeffrey Yasskin95fa80a2010-01-09 19:44:16 +0000[diff] [blame]5905 <ul>
5906 <li>Caller and callee both have the calling
5907 convention <tt>fastcc</tt>.</li>
5908 <li>The call is in tail position (ret immediately follows call and ret
5909 uses value of call or is void).</li>
5910 <li>Option <tt>-tailcallopt</tt> is enabled,
Dan Gohmanfbbee8d2010-03-02 01:08:11 +0000[diff] [blame]5911 or <code>llvm::GuaranteedTailCallOpt</code> is <code>true</code>.</li>
Jeffrey Yasskin95fa80a2010-01-09 19:44:16 +0000[diff] [blame]5912 <li><a href="CodeGenerator.html#tailcallopt">Platform specific
5913 constraints are met.</a></li>
5914 </ul>
5915 </li>
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]5916
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5917 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
5918 convention</a> the call should use. If none is specified, the call
Jeffrey Yasskin95fa80a2010-01-09 19:44:16 +0000[diff] [blame]5919 defaults to using C calling conventions. The calling convention of the
5920 call must match the calling convention of the target function, or else the
5921 behavior is undefined.</li>
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]5922
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5923 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
5924 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
5925 '<tt>inreg</tt>' attributes are valid here.</li>
5926
5927 <li>'<tt>ty</tt>': the type of the call instruction itself which is also the
5928 type of the return value. Functions that return no value are marked
5929 <tt><a href="#t_void">void</a></tt>.</li>
5930
5931 <li>'<tt>fnty</tt>': shall be the signature of the pointer to function value
5932 being invoked. The argument types must match the types implied by this
5933 signature. This type can be omitted if the function is not varargs and if
5934 the function type does not return a pointer to a function.</li>
5935
5936 <li>'<tt>fnptrval</tt>': An LLVM value containing a pointer to a function to
5937 be invoked. In most cases, this is a direct function invocation, but
5938 indirect <tt>call</tt>s are just as possible, calling an arbitrary pointer
5939 to function value.</li>
5940
5941 <li>'<tt>function args</tt>': argument list whose types match the function
Chris Lattner0724fbd2010-03-02 06:36:51 +0000[diff] [blame]5942 signature argument types and parameter attributes. All arguments must be
5943 of <a href="#t_firstclass">first class</a> type. If the function
5944 signature indicates the function accepts a variable number of arguments,
5945 the extra arguments can be specified.</li>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5946
5947 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
5948 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
5949 '<tt>readnone</tt>' attributes are valid here.</li>
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]5950</ol>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5951
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]5952<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5953<p>The '<tt>call</tt>' instruction is used to cause control flow to transfer to
5954 a specified function, with its incoming arguments bound to the specified
5955 values. Upon a '<tt><a href="#i_ret">ret</a></tt>' instruction in the called
5956 function, control flow continues with the instruction after the function
5957 call, and the return value of the function is bound to the result
5958 argument.</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5959
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]5960<h5>Example:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5961<pre>
Nick Lewyckydb7e3c92007-09-08 13:57:50 +0000[diff] [blame]5962 %retval = call i32 @test(i32 %argc)
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]5963 call i32 (i8*, ...)* @printf(i8* %msg, i32 12, i8 42) <i>; yields i32</i>
Chris Lattner772fccf2008-03-21 17:24:17 +0000[diff] [blame]5964 %X = tail call i32 @foo() <i>; yields i32</i>
5965 %Y = tail call <a href="#callingconv">fastcc</a> i32 @foo() <i>; yields i32</i>
5966 call void %foo(i8 97 signext)
Devang Patelc3fc6df2008-03-10 20:49:15 +0000[diff] [blame]5967
5968 %struct.A = type { i32, i8 }
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]5969 %r = call %struct.A @foo() <i>; yields { 32, i8 }</i>
Dan Gohmanb1e6b962008-10-04 19:00:07 +0000[diff] [blame]5970 %gr = extractvalue %struct.A %r, 0 <i>; yields i32</i>
5971 %gr1 = extractvalue %struct.A %r, 1 <i>; yields i8</i>
Chris Lattner85a350f2008-10-08 06:26:11 +0000[diff] [blame]5972 %Z = call void @foo() noreturn <i>; indicates that %foo never returns normally</i>
Matthijs Kooijmancb73d192008-10-07 10:03:45 +0000[diff] [blame]5973 %ZZ = call zeroext i32 @bar() <i>; Return value is %zero extended</i>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5974</pre>
5975
Dale Johannesen07de8d12009-09-24 18:38:21 +0000[diff] [blame]5976<p>llvm treats calls to some functions with names and arguments that match the
Dale Johannesen9f8380b2009-09-25 17:04:42 +0000[diff] [blame]5977standard C99 library as being the C99 library functions, and may perform
5978optimizations or generate code for them under that assumption. This is
5979something we'd like to change in the future to provide better support for
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]5980freestanding environments and non-C-based languages.</p>
Dale Johannesen07de8d12009-09-24 18:38:21 +0000[diff] [blame]5981
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5982</div>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5983
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5984<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5985<h4>
Chris Lattnerfb6977d2006-01-13 23:26:01 +0000[diff] [blame]5986 <a name="i_va_arg">'<tt>va_arg</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5987</h4>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5988
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5989<div>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5990
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]5991<h5>Syntax:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5992<pre>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]5993 &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]5994</pre>
5995
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]5996<h5>Overview:</h5>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]5997<p>The '<tt>va_arg</tt>' instruction is used to access arguments passed through
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5998 the "variable argument" area of a function call. It is used to implement the
5999 <tt>va_arg</tt> macro in C.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]6000
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]6001<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6002<p>This instruction takes a <tt>va_list*</tt> value and the type of the
6003 argument. It returns a value of the specified argument type and increments
6004 the <tt>va_list</tt> to point to the next argument. The actual type
6005 of <tt>va_list</tt> is target specific.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]6006
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]6007<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6008<p>The '<tt>va_arg</tt>' instruction loads an argument of the specified type
6009 from the specified <tt>va_list</tt> and causes the <tt>va_list</tt> to point
6010 to the next argument. For more information, see the variable argument
6011 handling <a href="#int_varargs">Intrinsic Functions</a>.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]6012
6013<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]6014 take a variable number of arguments, for example, the <tt>vfprintf</tt>
6015 function.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]6016
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6017<p><tt>va_arg</tt> is an LLVM instruction instead of
6018 an <a href="#intrinsics">intrinsic function</a> because it takes a type as an
6019 argument.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]6020
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]6021<h5>Example:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]6022<p>See the <a href="#int_varargs">variable argument processing</a> section.</p>
6023
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6024<p>Note that the code generator does not yet fully support va_arg on many
6025 targets. Also, it does not currently support va_arg with aggregate types on
6026 any target.</p>
Dan Gohmanf3e60bd2009-01-12 23:12:39 +0000[diff] [blame]6027
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]6028</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6029
Bill Wendlingf78faf82011-08-02 21:52:38 +0000[diff] [blame]6030<!-- _______________________________________________________________________ -->
6031<h4>
6032 <a name="i_landingpad">'<tt>landingpad</tt>' Instruction</a>
6033</h4>
6034
6035<div>
6036
6037<h5>Syntax:</h5>
6038<pre>
Bill Wendlingbf13ee12011-08-08 08:06:05 +0000[diff] [blame]6039 &lt;resultval&gt; = landingpad &lt;somety&gt; personality &lt;type&gt; &lt;pers_fn&gt; &lt;clause&gt;+
6040 &lt;resultval&gt; = landingpad &lt;somety&gt; personality &lt;type&gt; &lt;pers_fn&gt; cleanup &lt;clause&gt;*
6041
Bill Wendlingf78faf82011-08-02 21:52:38 +0000[diff] [blame]6042 &lt;clause&gt; := catch &lt;type&gt; &lt;value&gt;
Bill Wendlinge6e88262011-08-12 20:24:12 +0000[diff] [blame]6043 &lt;clause&gt; := filter &lt;array constant type&gt; &lt;array constant&gt;
Bill Wendlingf78faf82011-08-02 21:52:38 +0000[diff] [blame]6044</pre>
6045
6046<h5>Overview:</h5>
6047<p>The '<tt>landingpad</tt>' instruction is used by
6048 <a href="ExceptionHandling.html#overview">LLVM's exception handling
6049 system</a> to specify that a basic block is a landing pad &mdash; one where
6050 the exception lands, and corresponds to the code found in the
6051 <i><tt>catch</tt></i> portion of a <i><tt>try/catch</tt></i> sequence. It
6052 defines values supplied by the personality function (<tt>pers_fn</tt>) upon
6053 re-entry to the function. The <tt>resultval</tt> has the
6054 type <tt>somety</tt>.</p>
6055
6056<h5>Arguments:</h5>
6057<p>This instruction takes a <tt>pers_fn</tt> value. This is the personality
6058 function associated with the unwinding mechanism. The optional
6059 <tt>cleanup</tt> flag indicates that the landing pad block is a cleanup.</p>
6060
6061<p>A <tt>clause</tt> begins with the clause type &mdash; <tt>catch</tt>
Bill Wendlinge6e88262011-08-12 20:24:12 +0000[diff] [blame]6062 or <tt>filter</tt> &mdash; and contains the global variable representing the
6063 "type" that may be caught or filtered respectively. Unlike the
6064 <tt>catch</tt> clause, the <tt>filter</tt> clause takes an array constant as
6065 its argument. Use "<tt>[0 x i8**] undef</tt>" for a filter which cannot
6066 throw. The '<tt>landingpad</tt>' instruction must contain <em>at least</em>
Bill Wendlingf78faf82011-08-02 21:52:38 +0000[diff] [blame]6067 one <tt>clause</tt> or the <tt>cleanup</tt> flag.</p>
6068
6069<h5>Semantics:</h5>
6070<p>The '<tt>landingpad</tt>' instruction defines the values which are set by the
6071 personality function (<tt>pers_fn</tt>) upon re-entry to the function, and
6072 therefore the "result type" of the <tt>landingpad</tt> instruction. As with
6073 calling conventions, how the personality function results are represented in
6074 LLVM IR is target specific.</p>
6075
Bill Wendlingb7a01352011-08-03 17:17:06 +0000[diff] [blame]6076<p>The clauses are applied in order from top to bottom. If two
6077 <tt>landingpad</tt> instructions are merged together through inlining, the
Bill Wendling2905c322011-08-08 07:58:58 +0000[diff] [blame]6078 clauses from the calling function are appended to the list of clauses.</p>
Bill Wendlingb7a01352011-08-03 17:17:06 +0000[diff] [blame]6079
Bill Wendlingf78faf82011-08-02 21:52:38 +0000[diff] [blame]6080<p>The <tt>landingpad</tt> instruction has several restrictions:</p>
6081
6082<ul>
6083 <li>A landing pad block is a basic block which is the unwind destination of an
6084 '<tt>invoke</tt>' instruction.</li>
6085 <li>A landing pad block must have a '<tt>landingpad</tt>' instruction as its
6086 first non-PHI instruction.</li>
6087 <li>There can be only one '<tt>landingpad</tt>' instruction within the landing
6088 pad block.</li>
6089 <li>A basic block that is not a landing pad block may not include a
6090 '<tt>landingpad</tt>' instruction.</li>
6091 <li>All '<tt>landingpad</tt>' instructions in a function must have the same
6092 personality function.</li>
6093</ul>
6094
6095<h5>Example:</h5>
6096<pre>
6097 ;; A landing pad which can catch an integer.
6098 %res = landingpad { i8*, i32 } personality i32 (...)* @__gxx_personality_v0
6099 catch i8** @_ZTIi
6100 ;; A landing pad that is a cleanup.
6101 %res = landingpad { i8*, i32 } personality i32 (...)* @__gxx_personality_v0
Bill Wendlinge6e88262011-08-12 20:24:12 +0000[diff] [blame]6102 cleanup
Bill Wendlingf78faf82011-08-02 21:52:38 +0000[diff] [blame]6103 ;; A landing pad which can catch an integer and can only throw a double.
6104 %res = landingpad { i8*, i32 } personality i32 (...)* @__gxx_personality_v0
6105 catch i8** @_ZTIi
Bill Wendlinge6e88262011-08-12 20:24:12 +0000[diff] [blame]6106 filter [1 x i8**] [@_ZTId]
Bill Wendlingf78faf82011-08-02 21:52:38 +0000[diff] [blame]6107</pre>
6108
6109</div>
6110
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6111</div>
6112
6113</div>
6114
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6115<!-- *********************************************************************** -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6116<h2><a name="intrinsics">Intrinsic Functions</a></h2>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]6117<!-- *********************************************************************** -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6118
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6119<div>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6120
6121<p>LLVM supports the notion of an "intrinsic function". These functions have
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6122 well known names and semantics and are required to follow certain
6123 restrictions. Overall, these intrinsics represent an extension mechanism for
6124 the LLVM language that does not require changing all of the transformations
6125 in LLVM when adding to the language (or the bitcode reader/writer, the
6126 parser, etc...).</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6127
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]6128<p>Intrinsic function names must all start with an "<tt>llvm.</tt>" prefix. This
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6129 prefix is reserved in LLVM for intrinsic names; thus, function names may not
6130 begin with this prefix. Intrinsic functions must always be external
6131 functions: you cannot define the body of intrinsic functions. Intrinsic
6132 functions may only be used in call or invoke instructions: it is illegal to
6133 take the address of an intrinsic function. Additionally, because intrinsic
6134 functions are part of the LLVM language, it is required if any are added that
6135 they be documented here.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6136
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6137<p>Some intrinsic functions can be overloaded, i.e., the intrinsic represents a
6138 family of functions that perform the same operation but on different data
6139 types. Because LLVM can represent over 8 million different integer types,
6140 overloading is used commonly to allow an intrinsic function to operate on any
6141 integer type. One or more of the argument types or the result type can be
6142 overloaded to accept any integer type. Argument types may also be defined as
6143 exactly matching a previous argument's type or the result type. This allows
6144 an intrinsic function which accepts multiple arguments, but needs all of them
6145 to be of the same type, to only be overloaded with respect to a single
6146 argument or the result.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6147
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6148<p>Overloaded intrinsics will have the names of its overloaded argument types
6149 encoded into its function name, each preceded by a period. Only those types
6150 which are overloaded result in a name suffix. Arguments whose type is matched
6151 against another type do not. For example, the <tt>llvm.ctpop</tt> function
6152 can take an integer of any width and returns an integer of exactly the same
6153 integer width. This leads to a family of functions such as
6154 <tt>i8 @llvm.ctpop.i8(i8 %val)</tt> and <tt>i29 @llvm.ctpop.i29(i29
6155 %val)</tt>. Only one type, the return type, is overloaded, and only one type
6156 suffix is required. Because the argument's type is matched against the return
6157 type, it does not require its own name suffix.</p>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]6158
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]6159<p>To learn how to add an intrinsic function, please see the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6160 <a href="ExtendingLLVM.html">Extending LLVM Guide</a>.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6161
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6162<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6163<h3>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6164 <a name="int_varargs">Variable Argument Handling Intrinsics</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6165</h3>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6166
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6167<div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6168
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6169<p>Variable argument support is defined in LLVM with
6170 the <a href="#i_va_arg"><tt>va_arg</tt></a> instruction and these three
6171 intrinsic functions. These functions are related to the similarly named
6172 macros defined in the <tt>&lt;stdarg.h&gt;</tt> header file.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6173
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6174<p>All of these functions operate on arguments that use a target-specific value
6175 type "<tt>va_list</tt>". The LLVM assembly language reference manual does
6176 not define what this type is, so all transformations should be prepared to
6177 handle these functions regardless of the type used.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6178
Chris Lattner374ab302006-05-15 17:26:46 +0000[diff] [blame]6179<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]6180 instruction and the variable argument handling intrinsic functions are
6181 used.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6182
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]6183<pre class="doc_code">
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]6184define i32 @test(i32 %X, ...) {
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6185 ; Initialize variable argument processing
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]6186 %ap = alloca i8*
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]6187 %ap2 = bitcast i8** %ap to i8*
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]6188 call void @llvm.va_start(i8* %ap2)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6189
6190 ; Read a single integer argument
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]6191 %tmp = va_arg i8** %ap, i32
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6192
6193 ; Demonstrate usage of llvm.va_copy and llvm.va_end
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]6194 %aq = alloca i8*
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]6195 %aq2 = bitcast i8** %aq to i8*
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]6196 call void @llvm.va_copy(i8* %aq2, i8* %ap2)
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]6197 call void @llvm.va_end(i8* %aq2)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6198
6199 ; Stop processing of arguments.
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]6200 call void @llvm.va_end(i8* %ap2)
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]6201 ret i32 %tmp
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6202}
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]6203
6204declare void @llvm.va_start(i8*)
6205declare void @llvm.va_copy(i8*, i8*)
6206declare void @llvm.va_end(i8*)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6207</pre>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6208
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6209<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6210<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6211 <a name="int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6212</h4>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6213
6214
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6215<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6216
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6217<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6218<pre>
6219 declare void %llvm.va_start(i8* &lt;arglist&gt;)
6220</pre>
6221
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6222<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6223<p>The '<tt>llvm.va_start</tt>' intrinsic initializes <tt>*&lt;arglist&gt;</tt>
6224 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]6225
6226<h5>Arguments:</h5>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]6227<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]6228
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6229<h5>Semantics:</h5>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]6230<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]6231 macro available in C. In a target-dependent way, it initializes
6232 the <tt>va_list</tt> element to which the argument points, so that the next
6233 call to <tt>va_arg</tt> will produce the first variable argument passed to
6234 the function. Unlike the C <tt>va_start</tt> macro, this intrinsic does not
6235 need to know the last argument of the function as the compiler can figure
6236 that out.</p>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]6237
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]6238</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6239
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6240<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6241<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6242 <a name="int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6243</h4>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6244
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6245<div>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]6246
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6247<h5>Syntax:</h5>
6248<pre>
6249 declare void @llvm.va_end(i8* &lt;arglist&gt;)
6250</pre>
6251
6252<h5>Overview:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]6253<p>The '<tt>llvm.va_end</tt>' intrinsic destroys <tt>*&lt;arglist&gt;</tt>,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6254 which has been initialized previously
6255 with <tt><a href="#int_va_start">llvm.va_start</a></tt>
6256 or <tt><a href="#i_va_copy">llvm.va_copy</a></tt>.</p>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]6257
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6258<h5>Arguments:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]6259<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]6260
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6261<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]6262<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]6263 macro available in C. In a target-dependent way, it destroys
6264 the <tt>va_list</tt> element to which the argument points. Calls
6265 to <a href="#int_va_start"><tt>llvm.va_start</tt></a>
6266 and <a href="#int_va_copy"> <tt>llvm.va_copy</tt></a> must be matched exactly
6267 with calls to <tt>llvm.va_end</tt>.</p>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]6268
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]6269</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6270
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6271<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6272<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6273 <a name="int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6274</h4>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6275
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6276<div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6277
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6278<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6279<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]6280 declare void @llvm.va_copy(i8* &lt;destarglist&gt;, i8* &lt;srcarglist&gt;)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6281</pre>
6282
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6283<h5>Overview:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]6284<p>The '<tt>llvm.va_copy</tt>' intrinsic copies the current argument position
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6285 from the source argument list to the destination argument list.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6286
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6287<h5>Arguments:</h5>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]6288<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]6289 The second argument is a pointer to a <tt>va_list</tt> element to copy
6290 from.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6291
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6292<h5>Semantics:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]6293<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]6294 macro available in C. In a target-dependent way, it copies the
6295 source <tt>va_list</tt> element into the destination <tt>va_list</tt>
6296 element. This intrinsic is necessary because
6297 the <tt><a href="#int_va_start"> llvm.va_start</a></tt> intrinsic may be
6298 arbitrarily complex and require, for example, memory allocation.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6299
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]6300</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6301
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6302</div>
6303
Bill Wendling0246bb72011-07-31 06:45:03 +0000[diff] [blame]6304</div>
6305
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6306<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6307<h3>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6308 <a name="int_gc">Accurate Garbage Collection Intrinsics</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6309</h3>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6310
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6311<div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6312
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6313<p>LLVM support for <a href="GarbageCollection.html">Accurate Garbage
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]6314Collection</a> (GC) requires the implementation and generation of these
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6315intrinsics. These intrinsics allow identification of <a href="#int_gcroot">GC
6316roots on the stack</a>, as well as garbage collector implementations that
6317require <a href="#int_gcread">read</a> and <a href="#int_gcwrite">write</a>
6318barriers. Front-ends for type-safe garbage collected languages should generate
6319these intrinsics to make use of the LLVM garbage collectors. For more details,
6320see <a href="GarbageCollection.html">Accurate Garbage Collection with
6321LLVM</a>.</p>
Christopher Lamb303dae92007-12-17 01:00:21 +0000[diff] [blame]6322
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6323<p>The garbage collection intrinsics only operate on objects in the generic
6324 address space (address space zero).</p>
Christopher Lamb303dae92007-12-17 01:00:21 +0000[diff] [blame]6325
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6326<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6327<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6328 <a name="int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6329</h4>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6330
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6331<div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6332
6333<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6334<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]6335 declare void @llvm.gcroot(i8** %ptrloc, i8* %metadata)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6336</pre>
6337
6338<h5>Overview:</h5>
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]6339<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]6340 the code generator, and allows some metadata to be associated with it.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6341
6342<h5>Arguments:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6343<p>The first argument specifies the address of a stack object that contains the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6344 root pointer. The second pointer (which must be either a constant or a
6345 global value address) contains the meta-data to be associated with the
6346 root.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6347
6348<h5>Semantics:</h5>
Chris Lattner05d67092008-04-24 05:59:56 +0000[diff] [blame]6349<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]6350 location. At compile-time, the code generator generates information to allow
6351 the runtime to find the pointer at GC safe points. The '<tt>llvm.gcroot</tt>'
6352 intrinsic may only be used in a function which <a href="#gc">specifies a GC
6353 algorithm</a>.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6354
6355</div>
6356
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6357<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6358<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6359 <a name="int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6360</h4>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6361
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6362<div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6363
6364<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6365<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]6366 declare i8* @llvm.gcread(i8* %ObjPtr, i8** %Ptr)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6367</pre>
6368
6369<h5>Overview:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6370<p>The '<tt>llvm.gcread</tt>' intrinsic identifies reads of references from heap
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6371 locations, allowing garbage collector implementations that require read
6372 barriers.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6373
6374<h5>Arguments:</h5>
Chris Lattner80626e92006-03-14 20:02:51 +0000[diff] [blame]6375<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]6376 allocated from the garbage collector. The first object is a pointer to the
6377 start of the referenced object, if needed by the language runtime (otherwise
6378 null).</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6379
6380<h5>Semantics:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6381<p>The '<tt>llvm.gcread</tt>' intrinsic has the same semantics as a load
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6382 instruction, but may be replaced with substantially more complex code by the
6383 garbage collector runtime, as needed. The '<tt>llvm.gcread</tt>' intrinsic
6384 may only be used in a function which <a href="#gc">specifies a GC
6385 algorithm</a>.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6386
6387</div>
6388
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6389<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6390<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6391 <a name="int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6392</h4>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6393
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6394<div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6395
6396<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6397<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]6398 declare void @llvm.gcwrite(i8* %P1, i8* %Obj, i8** %P2)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6399</pre>
6400
6401<h5>Overview:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6402<p>The '<tt>llvm.gcwrite</tt>' intrinsic identifies writes of references to heap
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6403 locations, allowing garbage collector implementations that require write
6404 barriers (such as generational or reference counting collectors).</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6405
6406<h5>Arguments:</h5>
Chris Lattner80626e92006-03-14 20:02:51 +0000[diff] [blame]6407<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]6408 object to store it to, and the third is the address of the field of Obj to
6409 store to. If the runtime does not require a pointer to the object, Obj may
6410 be null.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6411
6412<h5>Semantics:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6413<p>The '<tt>llvm.gcwrite</tt>' intrinsic has the same semantics as a store
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6414 instruction, but may be replaced with substantially more complex code by the
6415 garbage collector runtime, as needed. The '<tt>llvm.gcwrite</tt>' intrinsic
6416 may only be used in a function which <a href="#gc">specifies a GC
6417 algorithm</a>.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6418
6419</div>
6420
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6421</div>
6422
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6423<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6424<h3>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6425 <a name="int_codegen">Code Generator Intrinsics</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6426</h3>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6427
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6428<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6429
6430<p>These intrinsics are provided by LLVM to expose special features that may
6431 only be implemented with code generator support.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6432
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6433<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6434<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6435 <a name="int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6436</h4>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6437
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6438<div>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6439
6440<h5>Syntax:</h5>
6441<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]6442 declare i8 *@llvm.returnaddress(i32 &lt;level&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6443</pre>
6444
6445<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6446<p>The '<tt>llvm.returnaddress</tt>' intrinsic attempts to compute a
6447 target-specific value indicating the return address of the current function
6448 or one of its callers.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6449
6450<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6451<p>The argument to this intrinsic indicates which function to return the address
6452 for. Zero indicates the calling function, one indicates its caller, etc.
6453 The argument is <b>required</b> to be a constant integer value.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6454
6455<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6456<p>The '<tt>llvm.returnaddress</tt>' intrinsic either returns a pointer
6457 indicating the return address of the specified call frame, or zero if it
6458 cannot be identified. The value returned by this intrinsic is likely to be
6459 incorrect or 0 for arguments other than zero, so it should only be used for
6460 debugging purposes.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6461
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6462<p>Note that calling this intrinsic does not prevent function inlining or other
6463 aggressive transformations, so the value returned may not be that of the
6464 obvious source-language caller.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6465
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6466</div>
6467
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6468<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6469<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6470 <a name="int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6471</h4>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6472
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6473<div>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6474
6475<h5>Syntax:</h5>
6476<pre>
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]6477 declare i8* @llvm.frameaddress(i32 &lt;level&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6478</pre>
6479
6480<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6481<p>The '<tt>llvm.frameaddress</tt>' intrinsic attempts to return the
6482 target-specific frame pointer value for the specified stack frame.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6483
6484<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6485<p>The argument to this intrinsic indicates which function to return the frame
6486 pointer for. Zero indicates the calling function, one indicates its caller,
6487 etc. The argument is <b>required</b> to be a constant integer value.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6488
6489<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6490<p>The '<tt>llvm.frameaddress</tt>' intrinsic either returns a pointer
6491 indicating the frame address of the specified call frame, or zero if it
6492 cannot be identified. The value returned by this intrinsic is likely to be
6493 incorrect or 0 for arguments other than zero, so it should only be used for
6494 debugging purposes.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6495
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6496<p>Note that calling this intrinsic does not prevent function inlining or other
6497 aggressive transformations, so the value returned may not be that of the
6498 obvious source-language caller.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6499
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6500</div>
6501
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]6502<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6503<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6504 <a name="int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6505</h4>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]6506
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6507<div>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]6508
6509<h5>Syntax:</h5>
6510<pre>
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]6511 declare i8* @llvm.stacksave()
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]6512</pre>
6513
6514<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6515<p>The '<tt>llvm.stacksave</tt>' intrinsic is used to remember the current state
6516 of the function stack, for use
6517 with <a href="#int_stackrestore"> <tt>llvm.stackrestore</tt></a>. This is
6518 useful for implementing language features like scoped automatic variable
6519 sized arrays in C99.</p>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]6520
6521<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6522<p>This intrinsic returns a opaque pointer value that can be passed
6523 to <a href="#int_stackrestore"><tt>llvm.stackrestore</tt></a>. When
6524 an <tt>llvm.stackrestore</tt> intrinsic is executed with a value saved
6525 from <tt>llvm.stacksave</tt>, it effectively restores the state of the stack
6526 to the state it was in when the <tt>llvm.stacksave</tt> intrinsic executed.
6527 In practice, this pops any <a href="#i_alloca">alloca</a> blocks from the
6528 stack that were allocated after the <tt>llvm.stacksave</tt> was executed.</p>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]6529
6530</div>
6531
6532<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6533<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6534 <a name="int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6535</h4>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]6536
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6537<div>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]6538
6539<h5>Syntax:</h5>
6540<pre>
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]6541 declare void @llvm.stackrestore(i8* %ptr)
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]6542</pre>
6543
6544<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6545<p>The '<tt>llvm.stackrestore</tt>' intrinsic is used to restore the state of
6546 the function stack to the state it was in when the
6547 corresponding <a href="#int_stacksave"><tt>llvm.stacksave</tt></a> intrinsic
6548 executed. This is useful for implementing language features like scoped
6549 automatic variable sized arrays in C99.</p>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]6550
6551<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6552<p>See the description
6553 for <a href="#int_stacksave"><tt>llvm.stacksave</tt></a>.</p>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]6554
6555</div>
6556
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]6557<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6558<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6559 <a name="int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6560</h4>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]6561
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6562<div>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]6563
6564<h5>Syntax:</h5>
6565<pre>
Bruno Cardoso Lopes9a767332011-06-14 04:58:37 +0000[diff] [blame]6566 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]6567</pre>
6568
6569<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6570<p>The '<tt>llvm.prefetch</tt>' intrinsic is a hint to the code generator to
6571 insert a prefetch instruction if supported; otherwise, it is a noop.
6572 Prefetches have no effect on the behavior of the program but can change its
6573 performance characteristics.</p>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]6574
6575<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6576<p><tt>address</tt> is the address to be prefetched, <tt>rw</tt> is the
6577 specifier determining if the fetch should be for a read (0) or write (1),
6578 and <tt>locality</tt> is a temporal locality specifier ranging from (0) - no
Bruno Cardoso Lopes9a767332011-06-14 04:58:37 +0000[diff] [blame]6579 locality, to (3) - extremely local keep in cache. The <tt>cache type</tt>
6580 specifies whether the prefetch is performed on the data (1) or instruction (0)
6581 cache. The <tt>rw</tt>, <tt>locality</tt> and <tt>cache type</tt> arguments
6582 must be constant integers.</p>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]6583
6584<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6585<p>This intrinsic does not modify the behavior of the program. In particular,
6586 prefetches cannot trap and do not produce a value. On targets that support
6587 this intrinsic, the prefetch can provide hints to the processor cache for
6588 better performance.</p>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]6589
6590</div>
6591
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]6592<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6593<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6594 <a name="int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6595</h4>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]6596
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6597<div>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]6598
6599<h5>Syntax:</h5>
6600<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]6601 declare void @llvm.pcmarker(i32 &lt;id&gt;)
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]6602</pre>
6603
6604<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6605<p>The '<tt>llvm.pcmarker</tt>' intrinsic is a method to export a Program
6606 Counter (PC) in a region of code to simulators and other tools. The method
6607 is target specific, but it is expected that the marker will use exported
6608 symbols to transmit the PC of the marker. The marker makes no guarantees
6609 that it will remain with any specific instruction after optimizations. It is
6610 possible that the presence of a marker will inhibit optimizations. The
6611 intended use is to be inserted after optimizations to allow correlations of
6612 simulation runs.</p>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]6613
6614<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6615<p><tt>id</tt> is a numerical id identifying the marker.</p>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]6616
6617<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6618<p>This intrinsic does not modify the behavior of the program. Backends that do
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]6619 not support this intrinsic may ignore it.</p>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]6620
6621</div>
6622
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]6623<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6624<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6625 <a name="int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6626</h4>
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]6627
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6628<div>
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]6629
6630<h5>Syntax:</h5>
6631<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]6632 declare i64 @llvm.readcyclecounter()
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]6633</pre>
6634
6635<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6636<p>The '<tt>llvm.readcyclecounter</tt>' intrinsic provides access to the cycle
6637 counter register (or similar low latency, high accuracy clocks) on those
6638 targets that support it. On X86, it should map to RDTSC. On Alpha, it
6639 should map to RPCC. As the backing counters overflow quickly (on the order
6640 of 9 seconds on alpha), this should only be used for small timings.</p>
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]6641
6642<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6643<p>When directly supported, reading the cycle counter should not modify any
6644 memory. Implementations are allowed to either return a application specific
6645 value or a system wide value. On backends without support, this is lowered
6646 to a constant 0.</p>
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]6647
6648</div>
6649
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6650</div>
6651
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6652<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6653<h3>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6654 <a name="int_libc">Standard C Library Intrinsics</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6655</h3>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6656
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6657<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6658
6659<p>LLVM provides intrinsics for a few important standard C library functions.
6660 These intrinsics allow source-language front-ends to pass information about
6661 the alignment of the pointer arguments to the code generator, providing
6662 opportunity for more efficient code generation.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6663
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6664<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6665<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6666 <a name="int_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6667</h4>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6668
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6669<div>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6670
6671<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6672<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]6673 integer bit width and for different address spaces. Not all targets support
6674 all bit widths however.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6675
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6676<pre>
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]6677 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]6678 i32 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]6679 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]6680 i64 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6681</pre>
6682
6683<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6684<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
6685 source location to the destination location.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6686
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6687<p>Note that, unlike the standard libc function, the <tt>llvm.memcpy.*</tt>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6688 intrinsics do not return a value, takes extra alignment/isvolatile arguments
6689 and the pointers can be in specified address spaces.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6690
6691<h5>Arguments:</h5>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6692
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6693<p>The first argument is a pointer to the destination, the second is a pointer
6694 to the source. The third argument is an integer argument specifying the
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6695 number of bytes to copy, the fourth argument is the alignment of the
6696 source and destination locations, and the fifth is a boolean indicating a
6697 volatile access.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6698
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]6699<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]6700 then the caller guarantees that both the source and destination pointers are
6701 aligned to that boundary.</p>
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]6702
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]6703<p>If the <tt>isvolatile</tt> parameter is <tt>true</tt>, the
6704 <tt>llvm.memcpy</tt> call is a <a href="#volatile">volatile operation</a>.
6705 The detailed access behavior is not very cleanly specified and it is unwise
6706 to depend on it.</p>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6707
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6708<h5>Semantics:</h5>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6709
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6710<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
6711 source location to the destination location, which are not allowed to
6712 overlap. It copies "len" bytes of memory over. If the argument is known to
6713 be aligned to some boundary, this can be specified as the fourth argument,
6714 otherwise it should be set to 0 or 1.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6715
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6716</div>
6717
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6718<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6719<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6720 <a name="int_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6721</h4>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6722
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6723<div>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6724
6725<h5>Syntax:</h5>
Chris Lattner824b9582008-11-21 16:42:48 +0000[diff] [blame]6726<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]6727 width and for different address space. Not all targets support all bit
6728 widths however.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6729
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6730<pre>
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]6731 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]6732 i32 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]6733 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]6734 i64 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6735</pre>
6736
6737<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6738<p>The '<tt>llvm.memmove.*</tt>' intrinsics move a block of memory from the
6739 source location to the destination location. It is similar to the
6740 '<tt>llvm.memcpy</tt>' intrinsic but allows the two memory locations to
6741 overlap.</p>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6742
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6743<p>Note that, unlike the standard libc function, the <tt>llvm.memmove.*</tt>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6744 intrinsics do not return a value, takes extra alignment/isvolatile arguments
6745 and the pointers can be in specified address spaces.</p>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6746
6747<h5>Arguments:</h5>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6748
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6749<p>The first argument is a pointer to the destination, the second is a pointer
6750 to the source. The third argument is an integer argument specifying the
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6751 number of bytes to copy, the fourth argument is the alignment of the
6752 source and destination locations, and the fifth is a boolean indicating a
6753 volatile access.</p>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6754
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]6755<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]6756 then the caller guarantees that the source and destination pointers are
6757 aligned to that boundary.</p>
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]6758
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]6759<p>If the <tt>isvolatile</tt> parameter is <tt>true</tt>, the
6760 <tt>llvm.memmove</tt> call is a <a href="#volatile">volatile operation</a>.
6761 The detailed access behavior is not very cleanly specified and it is unwise
6762 to depend on it.</p>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6763
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6764<h5>Semantics:</h5>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6765
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6766<p>The '<tt>llvm.memmove.*</tt>' intrinsics copy a block of memory from the
6767 source location to the destination location, which may overlap. It copies
6768 "len" bytes of memory over. If the argument is known to be aligned to some
6769 boundary, this can be specified as the fourth argument, otherwise it should
6770 be set to 0 or 1.</p>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6771
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6772</div>
6773
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6774<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6775<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6776 <a name="int_memset">'<tt>llvm.memset.*</tt>' Intrinsics</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6777</h4>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6778
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6779<div>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6780
6781<h5>Syntax:</h5>
Chris Lattner824b9582008-11-21 16:42:48 +0000[diff] [blame]6782<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]6783 width and for different address spaces. However, not all targets support all
6784 bit widths.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6785
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6786<pre>
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]6787 declare void @llvm.memset.p0i8.i32(i8* &lt;dest&gt;, i8 &lt;val&gt;,
Chris Lattnerff35c3f2010-04-08 00:54:34 +0000[diff] [blame]6788 i32 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]6789 declare void @llvm.memset.p0i8.i64(i8* &lt;dest&gt;, i8 &lt;val&gt;,
Chris Lattnerff35c3f2010-04-08 00:54:34 +0000[diff] [blame]6790 i64 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6791</pre>
6792
6793<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6794<p>The '<tt>llvm.memset.*</tt>' intrinsics fill a block of memory with a
6795 particular byte value.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6796
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6797<p>Note that, unlike the standard libc function, the <tt>llvm.memset</tt>
John Criswellcdcbbfc2010-07-30 16:30:28 +0000[diff] [blame]6798 intrinsic does not return a value and takes extra alignment/volatile
6799 arguments. Also, the destination can be in an arbitrary address space.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6800
6801<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6802<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]6803 byte value with which to fill it, the third argument is an integer argument
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6804 specifying the number of bytes to fill, and the fourth argument is the known
John Criswellcdcbbfc2010-07-30 16:30:28 +0000[diff] [blame]6805 alignment of the destination location.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6806
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]6807<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]6808 then the caller guarantees that the destination pointer is aligned to that
6809 boundary.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6810
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]6811<p>If the <tt>isvolatile</tt> parameter is <tt>true</tt>, the
6812 <tt>llvm.memset</tt> call is a <a href="#volatile">volatile operation</a>.
6813 The detailed access behavior is not very cleanly specified and it is unwise
6814 to depend on it.</p>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6815
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6816<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6817<p>The '<tt>llvm.memset.*</tt>' intrinsics fill "len" bytes of memory starting
6818 at the destination location. If the argument is known to be aligned to some
6819 boundary, this can be specified as the fourth argument, otherwise it should
6820 be set to 0 or 1.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6821
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6822</div>
6823
Chris Lattner32006282004-06-11 02:28:03 +0000[diff] [blame]6824<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6825<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6826 <a name="int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6827</h4>
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]6828
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6829<div>
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]6830
6831<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6832<p>This is an overloaded intrinsic. You can use <tt>llvm.sqrt</tt> on any
6833 floating point or vector of floating point type. Not all targets support all
6834 types however.</p>
6835
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]6836<pre>
Dale Johannesen408f9c12007-10-02 17:47:38 +0000[diff] [blame]6837 declare float @llvm.sqrt.f32(float %Val)
6838 declare double @llvm.sqrt.f64(double %Val)
6839 declare x86_fp80 @llvm.sqrt.f80(x86_fp80 %Val)
6840 declare fp128 @llvm.sqrt.f128(fp128 %Val)
6841 declare ppc_fp128 @llvm.sqrt.ppcf128(ppc_fp128 %Val)
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]6842</pre>
6843
6844<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6845<p>The '<tt>llvm.sqrt</tt>' intrinsics return the sqrt of the specified operand,
6846 returning the same value as the libm '<tt>sqrt</tt>' functions would.
6847 Unlike <tt>sqrt</tt> in libm, however, <tt>llvm.sqrt</tt> has undefined
6848 behavior for negative numbers other than -0.0 (which allows for better
6849 optimization, because there is no need to worry about errno being
6850 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]6851
6852<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6853<p>The argument and return value are floating point numbers of the same
6854 type.</p>
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]6855
6856<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6857<p>This function returns the sqrt of the specified operand if it is a
6858 nonnegative floating point number.</p>
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]6859
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]6860</div>
6861
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6862<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6863<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6864 <a name="int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6865</h4>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6866
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6867<div>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6868
6869<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6870<p>This is an overloaded intrinsic. You can use <tt>llvm.powi</tt> on any
6871 floating point or vector of floating point type. Not all targets support all
6872 types however.</p>
6873
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6874<pre>
Dale Johannesen408f9c12007-10-02 17:47:38 +0000[diff] [blame]6875 declare float @llvm.powi.f32(float %Val, i32 %power)
6876 declare double @llvm.powi.f64(double %Val, i32 %power)
6877 declare x86_fp80 @llvm.powi.f80(x86_fp80 %Val, i32 %power)
6878 declare fp128 @llvm.powi.f128(fp128 %Val, i32 %power)
6879 declare ppc_fp128 @llvm.powi.ppcf128(ppc_fp128 %Val, i32 %power)
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6880</pre>
6881
6882<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6883<p>The '<tt>llvm.powi.*</tt>' intrinsics return the first operand raised to the
6884 specified (positive or negative) power. The order of evaluation of
6885 multiplications is not defined. When a vector of floating point type is
6886 used, the second argument remains a scalar integer value.</p>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6887
6888<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6889<p>The second argument is an integer power, and the first is a value to raise to
6890 that power.</p>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6891
6892<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6893<p>This function returns the first value raised to the second power with an
6894 unspecified sequence of rounding operations.</p>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6895
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6896</div>
6897
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6898<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6899<h4>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6900 <a name="int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6901</h4>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6902
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6903<div>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6904
6905<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6906<p>This is an overloaded intrinsic. You can use <tt>llvm.sin</tt> on any
6907 floating point or vector of floating point type. Not all targets support all
6908 types however.</p>
6909
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6910<pre>
6911 declare float @llvm.sin.f32(float %Val)
6912 declare double @llvm.sin.f64(double %Val)
6913 declare x86_fp80 @llvm.sin.f80(x86_fp80 %Val)
6914 declare fp128 @llvm.sin.f128(fp128 %Val)
6915 declare ppc_fp128 @llvm.sin.ppcf128(ppc_fp128 %Val)
6916</pre>
6917
6918<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6919<p>The '<tt>llvm.sin.*</tt>' intrinsics return the sine of the operand.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6920
6921<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6922<p>The argument and return value are floating point numbers of the same
6923 type.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6924
6925<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6926<p>This function returns the sine of the specified operand, returning the same
6927 values as the libm <tt>sin</tt> functions would, and handles error conditions
6928 in the same way.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6929
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6930</div>
6931
6932<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6933<h4>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6934 <a name="int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6935</h4>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6936
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6937<div>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6938
6939<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6940<p>This is an overloaded intrinsic. You can use <tt>llvm.cos</tt> on any
6941 floating point or vector of floating point type. Not all targets support all
6942 types however.</p>
6943
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6944<pre>
6945 declare float @llvm.cos.f32(float %Val)
6946 declare double @llvm.cos.f64(double %Val)
6947 declare x86_fp80 @llvm.cos.f80(x86_fp80 %Val)
6948 declare fp128 @llvm.cos.f128(fp128 %Val)
6949 declare ppc_fp128 @llvm.cos.ppcf128(ppc_fp128 %Val)
6950</pre>
6951
6952<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6953<p>The '<tt>llvm.cos.*</tt>' intrinsics return the cosine of the operand.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6954
6955<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6956<p>The argument and return value are floating point numbers of the same
6957 type.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6958
6959<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6960<p>This function returns the cosine of the specified operand, returning the same
6961 values as the libm <tt>cos</tt> functions would, and handles error conditions
6962 in the same way.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6963
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6964</div>
6965
6966<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6967<h4>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6968 <a name="int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6969</h4>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6970
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6971<div>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6972
6973<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6974<p>This is an overloaded intrinsic. You can use <tt>llvm.pow</tt> on any
6975 floating point or vector of floating point type. Not all targets support all
6976 types however.</p>
6977
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6978<pre>
6979 declare float @llvm.pow.f32(float %Val, float %Power)
6980 declare double @llvm.pow.f64(double %Val, double %Power)
6981 declare x86_fp80 @llvm.pow.f80(x86_fp80 %Val, x86_fp80 %Power)
6982 declare fp128 @llvm.pow.f128(fp128 %Val, fp128 %Power)
6983 declare ppc_fp128 @llvm.pow.ppcf128(ppc_fp128 %Val, ppc_fp128 Power)
6984</pre>
6985
6986<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6987<p>The '<tt>llvm.pow.*</tt>' intrinsics return the first operand raised to the
6988 specified (positive or negative) power.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6989
6990<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6991<p>The second argument is a floating point power, and the first is a value to
6992 raise to that power.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6993
6994<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6995<p>This function returns the first value raised to the second power, returning
6996 the same values as the libm <tt>pow</tt> functions would, and handles error
6997 conditions in the same way.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6998
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6999</div>
7000
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7001</div>
7002
Dan Gohman4e9011c2011-05-23 21:13:03 +0000[diff] [blame]7003<!-- _______________________________________________________________________ -->
7004<h4>
7005 <a name="int_exp">'<tt>llvm.exp.*</tt>' Intrinsic</a>
7006</h4>
7007
7008<div>
7009
7010<h5>Syntax:</h5>
7011<p>This is an overloaded intrinsic. You can use <tt>llvm.exp</tt> on any
7012 floating point or vector of floating point type. Not all targets support all
7013 types however.</p>
7014
7015<pre>
7016 declare float @llvm.exp.f32(float %Val)
7017 declare double @llvm.exp.f64(double %Val)
7018 declare x86_fp80 @llvm.exp.f80(x86_fp80 %Val)
7019 declare fp128 @llvm.exp.f128(fp128 %Val)
7020 declare ppc_fp128 @llvm.exp.ppcf128(ppc_fp128 %Val)
7021</pre>
7022
7023<h5>Overview:</h5>
7024<p>The '<tt>llvm.exp.*</tt>' intrinsics perform the exp function.</p>
7025
7026<h5>Arguments:</h5>
7027<p>The argument and return value are floating point numbers of the same
7028 type.</p>
7029
7030<h5>Semantics:</h5>
7031<p>This function returns the same values as the libm <tt>exp</tt> functions
7032 would, and handles error conditions in the same way.</p>
7033
7034</div>
7035
7036<!-- _______________________________________________________________________ -->
7037<h4>
7038 <a name="int_log">'<tt>llvm.log.*</tt>' Intrinsic</a>
7039</h4>
7040
7041<div>
7042
7043<h5>Syntax:</h5>
7044<p>This is an overloaded intrinsic. You can use <tt>llvm.log</tt> on any
7045 floating point or vector of floating point type. Not all targets support all
7046 types however.</p>
7047
7048<pre>
7049 declare float @llvm.log.f32(float %Val)
7050 declare double @llvm.log.f64(double %Val)
7051 declare x86_fp80 @llvm.log.f80(x86_fp80 %Val)
7052 declare fp128 @llvm.log.f128(fp128 %Val)
7053 declare ppc_fp128 @llvm.log.ppcf128(ppc_fp128 %Val)
7054</pre>
7055
7056<h5>Overview:</h5>
7057<p>The '<tt>llvm.log.*</tt>' intrinsics perform the log function.</p>
7058
7059<h5>Arguments:</h5>
7060<p>The argument and return value are floating point numbers of the same
7061 type.</p>
7062
7063<h5>Semantics:</h5>
7064<p>This function returns the same values as the libm <tt>log</tt> functions
7065 would, and handles error conditions in the same way.</p>
7066
Cameron Zwarich33390842011-07-08 21:39:21 +0000[diff] [blame]7067<h4>
7068 <a name="int_fma">'<tt>llvm.fma.*</tt>' Intrinsic</a>
7069</h4>
7070
7071<div>
7072
7073<h5>Syntax:</h5>
7074<p>This is an overloaded intrinsic. You can use <tt>llvm.fma</tt> on any
7075 floating point or vector of floating point type. Not all targets support all
7076 types however.</p>
7077
7078<pre>
7079 declare float @llvm.fma.f32(float %a, float %b, float %c)
7080 declare double @llvm.fma.f64(double %a, double %b, double %c)
7081 declare x86_fp80 @llvm.fma.f80(x86_fp80 %a, x86_fp80 %b, x86_fp80 %c)
7082 declare fp128 @llvm.fma.f128(fp128 %a, fp128 %b, fp128 %c)
7083 declare ppc_fp128 @llvm.fma.ppcf128(ppc_fp128 %a, ppc_fp128 %b, ppc_fp128 %c)
7084</pre>
7085
7086<h5>Overview:</h5>
Cameron Zwarichabc43e62011-07-08 22:13:55 +0000[diff] [blame]7087<p>The '<tt>llvm.fma.*</tt>' intrinsics perform the fused multiply-add
Cameron Zwarich33390842011-07-08 21:39:21 +0000[diff] [blame]7088 operation.</p>
7089
7090<h5>Arguments:</h5>
7091<p>The argument and return value are floating point numbers of the same
7092 type.</p>
7093
7094<h5>Semantics:</h5>
7095<p>This function returns the same values as the libm <tt>fma</tt> functions
7096 would.</p>
7097
Dan Gohman4e9011c2011-05-23 21:13:03 +0000[diff] [blame]7098</div>
7099
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7100<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7101<h3>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]7102 <a name="int_manip">Bit Manipulation Intrinsics</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7103</h3>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7104
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7105<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7106
7107<p>LLVM provides intrinsics for a few important bit manipulation operations.
7108 These allow efficient code generation for some algorithms.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7109
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7110<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7111<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]7112 <a name="int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7113</h4>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]7114
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7115<div>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]7116
7117<h5>Syntax:</h5>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]7118<p>This is an overloaded intrinsic function. You can use bswap on any integer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7119 type that is an even number of bytes (i.e. BitWidth % 16 == 0).</p>
7120
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]7121<pre>
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]7122 declare i16 @llvm.bswap.i16(i16 &lt;id&gt;)
7123 declare i32 @llvm.bswap.i32(i32 &lt;id&gt;)
7124 declare i64 @llvm.bswap.i64(i64 &lt;id&gt;)
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]7125</pre>
7126
7127<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7128<p>The '<tt>llvm.bswap</tt>' family of intrinsics is used to byte swap integer
7129 values with an even number of bytes (positive multiple of 16 bits). These
7130 are useful for performing operations on data that is not in the target's
7131 native byte order.</p>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]7132
7133<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7134<p>The <tt>llvm.bswap.i16</tt> intrinsic returns an i16 value that has the high
7135 and low byte of the input i16 swapped. Similarly,
7136 the <tt>llvm.bswap.i32</tt> intrinsic returns an i32 value that has the four
7137 bytes of the input i32 swapped, so that if the input bytes are numbered 0, 1,
7138 2, 3 then the returned i32 will have its bytes in 3, 2, 1, 0 order.
7139 The <tt>llvm.bswap.i48</tt>, <tt>llvm.bswap.i64</tt> and other intrinsics
7140 extend this concept to additional even-byte lengths (6 bytes, 8 bytes and
7141 more, respectively).</p>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]7142
7143</div>
7144
7145<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7146<h4>
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]7147 <a name="int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7148</h4>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7149
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7150<div>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7151
7152<h5>Syntax:</h5>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]7153<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]7154 width, or on any vector with integer elements. Not all targets support all
7155 bit widths or vector types, however.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7156
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7157<pre>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7158 declare i8 @llvm.ctpop.i8(i8 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]7159 declare i16 @llvm.ctpop.i16(i16 &lt;src&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]7160 declare i32 @llvm.ctpop.i32(i32 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]7161 declare i64 @llvm.ctpop.i64(i64 &lt;src&gt;)
7162 declare i256 @llvm.ctpop.i256(i256 &lt;src&gt;)
Owen Andersonf1ac4652011-07-01 21:52:38 +0000[diff] [blame]7163 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]7164</pre>
7165
7166<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7167<p>The '<tt>llvm.ctpop</tt>' family of intrinsics counts the number of bits set
7168 in a value.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7169
7170<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7171<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]7172 integer type, or a vector with integer elements.
7173 The return type must match the argument type.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7174
7175<h5>Semantics:</h5>
Owen Andersonf1ac4652011-07-01 21:52:38 +0000[diff] [blame]7176<p>The '<tt>llvm.ctpop</tt>' intrinsic counts the 1's in a variable, or within each
7177 element of a vector.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7178
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7179</div>
7180
7181<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7182<h4>
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]7183 <a name="int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7184</h4>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7185
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7186<div>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7187
7188<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7189<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]7190 integer bit width, or any vector whose elements are integers. Not all
7191 targets support all bit widths or vector types, however.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7192
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7193<pre>
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]7194 declare i8 @llvm.ctlz.i8 (i8 &lt;src&gt;)
7195 declare i16 @llvm.ctlz.i16(i16 &lt;src&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]7196 declare i32 @llvm.ctlz.i32(i32 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]7197 declare i64 @llvm.ctlz.i64(i64 &lt;src&gt;)
7198 declare i256 @llvm.ctlz.i256(i256 &lt;src&gt;)
Owen Andersonf1ac4652011-07-01 21:52:38 +0000[diff] [blame]7199 declare &lt;2 x i32&gt; @llvm.ctlz.v2i32(&lt;2 x i32&gt; &lt;src;gt)
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7200</pre>
7201
7202<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7203<p>The '<tt>llvm.ctlz</tt>' family of intrinsic functions counts the number of
7204 leading zeros in a variable.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7205
7206<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7207<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]7208 integer type, or any vector type with integer element type.
7209 The return type must match the argument type.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7210
7211<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7212<p>The '<tt>llvm.ctlz</tt>' intrinsic counts the leading (most significant)
Owen Andersonf1ac4652011-07-01 21:52:38 +0000[diff] [blame]7213 zeros in a variable, or within each element of the vector if the operation
7214 is of vector type. If the src == 0 then the result is the size in bits of
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7215 the type of src. For example, <tt>llvm.ctlz(i32 2) = 30</tt>.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7216
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7217</div>
Chris Lattner32006282004-06-11 02:28:03 +0000[diff] [blame]7218
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]7219<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7220<h4>
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]7221 <a name="int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7222</h4>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]7223
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7224<div>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]7225
7226<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7227<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]7228 integer bit width, or any vector of integer elements. Not all targets
7229 support all bit widths or vector types, however.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7230
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]7231<pre>
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]7232 declare i8 @llvm.cttz.i8 (i8 &lt;src&gt;)
7233 declare i16 @llvm.cttz.i16(i16 &lt;src&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]7234 declare i32 @llvm.cttz.i32(i32 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]7235 declare i64 @llvm.cttz.i64(i64 &lt;src&gt;)
7236 declare i256 @llvm.cttz.i256(i256 &lt;src&gt;)
Owen Andersonf1ac4652011-07-01 21:52:38 +0000[diff] [blame]7237 declase &lt;2 x i32&gt; @llvm.cttz.v2i32(&lt;2 x i32&gt; &lt;src&gt;)
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]7238</pre>
7239
7240<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7241<p>The '<tt>llvm.cttz</tt>' family of intrinsic functions counts the number of
7242 trailing zeros.</p>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]7243
7244<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7245<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]7246 integer type, or a vectory with integer element type.. The return type
7247 must match the argument type.</p>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]7248
7249<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7250<p>The '<tt>llvm.cttz</tt>' intrinsic counts the trailing (least significant)
Owen Andersonf1ac4652011-07-01 21:52:38 +0000[diff] [blame]7251 zeros in a variable, or within each element of a vector.
7252 If the src == 0 then the result is the size in bits of
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7253 the type of src. For example, <tt>llvm.cttz(2) = 1</tt>.</p>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]7254
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]7255</div>
7256
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7257</div>
7258
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]7259<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7260<h3>
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]7261 <a name="int_overflow">Arithmetic with Overflow Intrinsics</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7262</h3>
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]7263
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7264<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7265
7266<p>LLVM provides intrinsics for some arithmetic with overflow operations.</p>
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]7267
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7268<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7269<h4>
7270 <a name="int_sadd_overflow">
7271 '<tt>llvm.sadd.with.overflow.*</tt>' Intrinsics
7272 </a>
7273</h4>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7274
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7275<div>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7276
7277<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7278<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]7279 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7280
7281<pre>
7282 declare {i16, i1} @llvm.sadd.with.overflow.i16(i16 %a, i16 %b)
7283 declare {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
7284 declare {i64, i1} @llvm.sadd.with.overflow.i64(i64 %a, i64 %b)
7285</pre>
7286
7287<h5>Overview:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7288<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7289 a signed addition of the two arguments, and indicate whether an overflow
7290 occurred during the signed summation.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7291
7292<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7293<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]7294 be of integer types of any bit width, but they must have the same bit
7295 width. The second element of the result structure must be of
7296 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
7297 undergo signed addition.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7298
7299<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7300<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7301 a signed addition of the two variables. They return a structure &mdash; the
7302 first element of which is the signed summation, and the second element of
7303 which is a bit specifying if the signed summation resulted in an
7304 overflow.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7305
7306<h5>Examples:</h5>
7307<pre>
7308 %res = call {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
7309 %sum = extractvalue {i32, i1} %res, 0
7310 %obit = extractvalue {i32, i1} %res, 1
7311 br i1 %obit, label %overflow, label %normal
7312</pre>
7313
7314</div>
7315
7316<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7317<h4>
7318 <a name="int_uadd_overflow">
7319 '<tt>llvm.uadd.with.overflow.*</tt>' Intrinsics
7320 </a>
7321</h4>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7322
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7323<div>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7324
7325<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7326<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]7327 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7328
7329<pre>
7330 declare {i16, i1} @llvm.uadd.with.overflow.i16(i16 %a, i16 %b)
7331 declare {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
7332 declare {i64, i1} @llvm.uadd.with.overflow.i64(i64 %a, i64 %b)
7333</pre>
7334
7335<h5>Overview:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7336<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7337 an unsigned addition of the two arguments, and indicate whether a carry
7338 occurred during the unsigned summation.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7339
7340<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7341<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]7342 be of integer types of any bit width, but they must have the same bit
7343 width. The second element of the result structure must be of
7344 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
7345 undergo unsigned addition.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7346
7347<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7348<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7349 an unsigned addition of the two arguments. They return a structure &mdash;
7350 the first element of which is the sum, and the second element of which is a
7351 bit specifying if the unsigned summation resulted in a carry.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7352
7353<h5>Examples:</h5>
7354<pre>
7355 %res = call {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
7356 %sum = extractvalue {i32, i1} %res, 0
7357 %obit = extractvalue {i32, i1} %res, 1
7358 br i1 %obit, label %carry, label %normal
7359</pre>
7360
7361</div>
7362
7363<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7364<h4>
7365 <a name="int_ssub_overflow">
7366 '<tt>llvm.ssub.with.overflow.*</tt>' Intrinsics
7367 </a>
7368</h4>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7369
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7370<div>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7371
7372<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7373<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]7374 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7375
7376<pre>
7377 declare {i16, i1} @llvm.ssub.with.overflow.i16(i16 %a, i16 %b)
7378 declare {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
7379 declare {i64, i1} @llvm.ssub.with.overflow.i64(i64 %a, i64 %b)
7380</pre>
7381
7382<h5>Overview:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7383<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7384 a signed subtraction of the two arguments, and indicate whether an overflow
7385 occurred during the signed subtraction.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7386
7387<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7388<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]7389 be of integer types of any bit width, but they must have the same bit
7390 width. The second element of the result structure must be of
7391 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
7392 undergo signed subtraction.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7393
7394<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7395<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7396 a signed subtraction of the two arguments. They return a structure &mdash;
7397 the first element of which is the subtraction, and the second element of
7398 which is a bit specifying if the signed subtraction resulted in an
7399 overflow.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7400
7401<h5>Examples:</h5>
7402<pre>
7403 %res = call {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
7404 %sum = extractvalue {i32, i1} %res, 0
7405 %obit = extractvalue {i32, i1} %res, 1
7406 br i1 %obit, label %overflow, label %normal
7407</pre>
7408
7409</div>
7410
7411<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7412<h4>
7413 <a name="int_usub_overflow">
7414 '<tt>llvm.usub.with.overflow.*</tt>' Intrinsics
7415 </a>
7416</h4>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7417
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7418<div>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7419
7420<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7421<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]7422 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7423
7424<pre>
7425 declare {i16, i1} @llvm.usub.with.overflow.i16(i16 %a, i16 %b)
7426 declare {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
7427 declare {i64, i1} @llvm.usub.with.overflow.i64(i64 %a, i64 %b)
7428</pre>
7429
7430<h5>Overview:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7431<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7432 an unsigned subtraction of the two arguments, and indicate whether an
7433 overflow occurred during the unsigned subtraction.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7434
7435<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7436<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]7437 be of integer types of any bit width, but they must have the same bit
7438 width. The second element of the result structure must be of
7439 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
7440 undergo unsigned subtraction.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7441
7442<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7443<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7444 an unsigned subtraction of the two arguments. They return a structure &mdash;
7445 the first element of which is the subtraction, and the second element of
7446 which is a bit specifying if the unsigned subtraction resulted in an
7447 overflow.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7448
7449<h5>Examples:</h5>
7450<pre>
7451 %res = call {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
7452 %sum = extractvalue {i32, i1} %res, 0
7453 %obit = extractvalue {i32, i1} %res, 1
7454 br i1 %obit, label %overflow, label %normal
7455</pre>
7456
7457</div>
7458
7459<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7460<h4>
7461 <a name="int_smul_overflow">
7462 '<tt>llvm.smul.with.overflow.*</tt>' Intrinsics
7463 </a>
7464</h4>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7465
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7466<div>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7467
7468<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7469<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]7470 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7471
7472<pre>
7473 declare {i16, i1} @llvm.smul.with.overflow.i16(i16 %a, i16 %b)
7474 declare {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
7475 declare {i64, i1} @llvm.smul.with.overflow.i64(i64 %a, i64 %b)
7476</pre>
7477
7478<h5>Overview:</h5>
7479
7480<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7481 a signed multiplication of the two arguments, and indicate whether an
7482 overflow occurred during the signed multiplication.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7483
7484<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7485<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]7486 be of integer types of any bit width, but they must have the same bit
7487 width. The second element of the result structure must be of
7488 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
7489 undergo signed multiplication.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7490
7491<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7492<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7493 a signed multiplication of the two arguments. They return a structure &mdash;
7494 the first element of which is the multiplication, and the second element of
7495 which is a bit specifying if the signed multiplication resulted in an
7496 overflow.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7497
7498<h5>Examples:</h5>
7499<pre>
7500 %res = call {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
7501 %sum = extractvalue {i32, i1} %res, 0
7502 %obit = extractvalue {i32, i1} %res, 1
7503 br i1 %obit, label %overflow, label %normal
7504</pre>
7505
Reid Spencerf86037f2007-04-11 23:23:49 +0000[diff] [blame]7506</div>
7507
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]7508<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7509<h4>
7510 <a name="int_umul_overflow">
7511 '<tt>llvm.umul.with.overflow.*</tt>' Intrinsics
7512 </a>
7513</h4>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]7514
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7515<div>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]7516
7517<h5>Syntax:</h5>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]7518<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]7519 on any integer bit width.</p>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]7520
7521<pre>
7522 declare {i16, i1} @llvm.umul.with.overflow.i16(i16 %a, i16 %b)
7523 declare {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
7524 declare {i64, i1} @llvm.umul.with.overflow.i64(i64 %a, i64 %b)
7525</pre>
7526
7527<h5>Overview:</h5>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]7528<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7529 a unsigned multiplication of the two arguments, and indicate whether an
7530 overflow occurred during the unsigned multiplication.</p>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]7531
7532<h5>Arguments:</h5>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]7533<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]7534 be of integer types of any bit width, but they must have the same bit
7535 width. The second element of the result structure must be of
7536 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
7537 undergo unsigned multiplication.</p>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]7538
7539<h5>Semantics:</h5>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]7540<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7541 an unsigned multiplication of the two arguments. They return a structure
7542 &mdash; the first element of which is the multiplication, and the second
7543 element of which is a bit specifying if the unsigned multiplication resulted
7544 in an overflow.</p>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]7545
7546<h5>Examples:</h5>
7547<pre>
7548 %res = call {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
7549 %sum = extractvalue {i32, i1} %res, 0
7550 %obit = extractvalue {i32, i1} %res, 1
7551 br i1 %obit, label %overflow, label %normal
7552</pre>
7553
7554</div>
7555
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7556</div>
7557
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]7558<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7559<h3>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]7560 <a name="int_fp16">Half Precision Floating Point Intrinsics</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7561</h3>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]7562
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7563<div>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]7564
Chris Lattner0cec9c82010-03-15 04:12:21 +0000[diff] [blame]7565<p>Half precision floating point is a storage-only format. This means that it is
7566 a dense encoding (in memory) but does not support computation in the
7567 format.</p>
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]7568
Chris Lattner0cec9c82010-03-15 04:12:21 +0000[diff] [blame]7569<p>This means that code must first load the half-precision floating point
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]7570 value as an i16, then convert it to float with <a
7571 href="#int_convert_from_fp16"><tt>llvm.convert.from.fp16</tt></a>.
7572 Computation can then be performed on the float value (including extending to
Chris Lattner0cec9c82010-03-15 04:12:21 +0000[diff] [blame]7573 double etc). To store the value back to memory, it is first converted to
7574 float if needed, then converted to i16 with
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]7575 <a href="#int_convert_to_fp16"><tt>llvm.convert.to.fp16</tt></a>, then
7576 storing as an i16 value.</p>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]7577
7578<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7579<h4>
7580 <a name="int_convert_to_fp16">
7581 '<tt>llvm.convert.to.fp16</tt>' Intrinsic
7582 </a>
7583</h4>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]7584
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7585<div>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]7586
7587<h5>Syntax:</h5>
7588<pre>
7589 declare i16 @llvm.convert.to.fp16(f32 %a)
7590</pre>
7591
7592<h5>Overview:</h5>
7593<p>The '<tt>llvm.convert.to.fp16</tt>' intrinsic function performs
7594 a conversion from single precision floating point format to half precision
7595 floating point format.</p>
7596
7597<h5>Arguments:</h5>
7598<p>The intrinsic function contains single argument - the value to be
7599 converted.</p>
7600
7601<h5>Semantics:</h5>
7602<p>The '<tt>llvm.convert.to.fp16</tt>' intrinsic function performs
7603 a conversion from single precision floating point format to half precision
Chris Lattner0cec9c82010-03-15 04:12:21 +0000[diff] [blame]7604 floating point format. The return value is an <tt>i16</tt> which
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]7605 contains the converted number.</p>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]7606
7607<h5>Examples:</h5>
7608<pre>
7609 %res = call i16 @llvm.convert.to.fp16(f32 %a)
7610 store i16 %res, i16* @x, align 2
7611</pre>
7612
7613</div>
7614
7615<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7616<h4>
7617 <a name="int_convert_from_fp16">
7618 '<tt>llvm.convert.from.fp16</tt>' Intrinsic
7619 </a>
7620</h4>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]7621
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7622<div>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]7623
7624<h5>Syntax:</h5>
7625<pre>
7626 declare f32 @llvm.convert.from.fp16(i16 %a)
7627</pre>
7628
7629<h5>Overview:</h5>
7630<p>The '<tt>llvm.convert.from.fp16</tt>' intrinsic function performs
7631 a conversion from half precision floating point format to single precision
7632 floating point format.</p>
7633
7634<h5>Arguments:</h5>
7635<p>The intrinsic function contains single argument - the value to be
7636 converted.</p>
7637
7638<h5>Semantics:</h5>
7639<p>The '<tt>llvm.convert.from.fp16</tt>' intrinsic function performs a
Chris Lattner0cec9c82010-03-15 04:12:21 +0000[diff] [blame]7640 conversion from half single precision floating point format to single
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]7641 precision floating point format. The input half-float value is represented by
7642 an <tt>i16</tt> value.</p>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]7643
7644<h5>Examples:</h5>
7645<pre>
7646 %a = load i16* @x, align 2
7647 %res = call f32 @llvm.convert.from.fp16(i16 %a)
7648</pre>
7649
7650</div>
7651
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7652</div>
7653
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]7654<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7655<h3>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]7656 <a name="int_debugger">Debugger Intrinsics</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7657</h3>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]7658
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7659<div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]7660
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7661<p>The LLVM debugger intrinsics (which all start with <tt>llvm.dbg.</tt>
7662 prefix), are described in
7663 the <a href="SourceLevelDebugging.html#format_common_intrinsics">LLVM Source
7664 Level Debugging</a> document.</p>
7665
7666</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]7667
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]7668<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7669<h3>
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]7670 <a name="int_eh">Exception Handling Intrinsics</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7671</h3>
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]7672
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7673<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7674
7675<p>The LLVM exception handling intrinsics (which all start with
7676 <tt>llvm.eh.</tt> prefix), are described in
7677 the <a href="ExceptionHandling.html#format_common_intrinsics">LLVM Exception
7678 Handling</a> document.</p>
7679
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]7680</div>
7681
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]7682<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7683<h3>
Duncan Sands4a544a72011-09-06 13:37:06 +0000[diff] [blame]7684 <a name="int_trampoline">Trampoline Intrinsics</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7685</h3>
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]7686
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7687<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7688
Duncan Sands4a544a72011-09-06 13:37:06 +0000[diff] [blame]7689<p>These intrinsics make it possible to excise one parameter, marked with
Dan Gohmanff235352010-07-02 23:18:08 +0000[diff] [blame]7690 the <a href="#nest"><tt>nest</tt></a> attribute, from a function.
7691 The result is a callable
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7692 function pointer lacking the nest parameter - the caller does not need to
7693 provide a value for it. Instead, the value to use is stored in advance in a
7694 "trampoline", a block of memory usually allocated on the stack, which also
7695 contains code to splice the nest value into the argument list. This is used
7696 to implement the GCC nested function address extension.</p>
7697
7698<p>For example, if the function is
7699 <tt>i32 f(i8* nest %c, i32 %x, i32 %y)</tt> then the resulting function
7700 pointer has signature <tt>i32 (i32, i32)*</tt>. It can be created as
7701 follows:</p>
7702
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]7703<pre class="doc_code">
Duncan Sandsf7331b32007-09-11 14:10:23 +0000[diff] [blame]7704 %tramp = alloca [10 x i8], align 4 ; size and alignment only correct for X86
7705 %tramp1 = getelementptr [10 x i8]* %tramp, i32 0, i32 0
Duncan Sands4a544a72011-09-06 13:37:06 +0000[diff] [blame]7706 call i8* @llvm.init.trampoline(i8* %tramp1, i8* bitcast (i32 (i8*, i32, i32)* @f to i8*), i8* %nval)
7707 %p = call i8* @llvm.adjust.trampoline(i8* %tramp1)
Duncan Sandsf7331b32007-09-11 14:10:23 +0000[diff] [blame]7708 %fp = bitcast i8* %p to i32 (i32, i32)*
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]7709</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7710
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7711<p>The call <tt>%val = call i32 %fp(i32 %x, i32 %y)</tt> is then equivalent
7712 to <tt>%val = call i32 %f(i8* %nval, i32 %x, i32 %y)</tt>.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7713
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]7714<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7715<h4>
7716 <a name="int_it">
7717 '<tt>llvm.init.trampoline</tt>' Intrinsic
7718 </a>
7719</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7720
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7721<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7722
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]7723<h5>Syntax:</h5>
7724<pre>
Duncan Sands4a544a72011-09-06 13:37:06 +0000[diff] [blame]7725 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]7726</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7727
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]7728<h5>Overview:</h5>
Duncan Sands4a544a72011-09-06 13:37:06 +0000[diff] [blame]7729<p>This fills the memory pointed to by <tt>tramp</tt> with executable code,
7730 turning it into a trampoline.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7731
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]7732<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7733<p>The <tt>llvm.init.trampoline</tt> intrinsic takes three arguments, all
7734 pointers. The <tt>tramp</tt> argument must point to a sufficiently large and
7735 sufficiently aligned block of memory; this memory is written to by the
7736 intrinsic. Note that the size and the alignment are target-specific - LLVM
7737 currently provides no portable way of determining them, so a front-end that
7738 generates this intrinsic needs to have some target-specific knowledge.
7739 The <tt>func</tt> argument must hold a function bitcast to
7740 an <tt>i8*</tt>.</p>
7741
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]7742<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7743<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]7744 dependent code, turning it into a function. Then <tt>tramp</tt> needs to be
7745 passed to <a href="#int_at">llvm.adjust.trampoline</a> to get a pointer
7746 which can be <a href="#int_trampoline">bitcast (to a new function) and
7747 called</a>. The new function's signature is the same as that of
7748 <tt>func</tt> with any arguments marked with the <tt>nest</tt> attribute
7749 removed. At most one such <tt>nest</tt> argument is allowed, and it must be of
7750 pointer type. Calling the new function is equivalent to calling <tt>func</tt>
7751 with the same argument list, but with <tt>nval</tt> used for the missing
7752 <tt>nest</tt> argument. If, after calling <tt>llvm.init.trampoline</tt>, the
7753 memory pointed to by <tt>tramp</tt> is modified, then the effect of any later call
7754 to the returned function pointer is undefined.</p>
7755</div>
7756
7757<!-- _______________________________________________________________________ -->
7758<h4>
7759 <a name="int_at">
7760 '<tt>llvm.adjust.trampoline</tt>' Intrinsic
7761 </a>
7762</h4>
7763
7764<div>
7765
7766<h5>Syntax:</h5>
7767<pre>
7768 declare i8* @llvm.adjust.trampoline(i8* &lt;tramp&gt;)
7769</pre>
7770
7771<h5>Overview:</h5>
7772<p>This performs any required machine-specific adjustment to the address of a
7773 trampoline (passed as <tt>tramp</tt>).</p>
7774
7775<h5>Arguments:</h5>
7776<p><tt>tramp</tt> must point to a block of memory which already has trampoline code
7777 filled in by a previous call to <a href="#int_it"><tt>llvm.init.trampoline</tt>
7778 </a>.</p>
7779
7780<h5>Semantics:</h5>
7781<p>On some architectures the address of the code to be executed needs to be
7782 different to the address where the trampoline is actually stored. This
7783 intrinsic returns the executable address corresponding to <tt>tramp</tt>
7784 after performing the required machine specific adjustments.
7785 The pointer returned can then be <a href="#int_trampoline"> bitcast and
7786 executed</a>.
7787</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7788
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]7789</div>
7790
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7791</div>
7792
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]7793<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7794<h3>
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7795 <a name="int_atomics">Atomic Operations and Synchronization Intrinsics</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7796</h3>
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7797
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7798<div>
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7799
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7800<p>These intrinsic functions expand the "universal IR" of LLVM to represent
7801 hardware constructs for atomic operations and memory synchronization. This
7802 provides an interface to the hardware, not an interface to the programmer. It
7803 is aimed at a low enough level to allow any programming models or APIs
7804 (Application Programming Interfaces) which need atomic behaviors to map
7805 cleanly onto it. It is also modeled primarily on hardware behavior. Just as
7806 hardware provides a "universal IR" for source languages, it also provides a
7807 starting point for developing a "universal" atomic operation and
7808 synchronization IR.</p>
7809
7810<p>These do <em>not</em> form an API such as high-level threading libraries,
7811 software transaction memory systems, atomic primitives, and intrinsic
7812 functions as found in BSD, GNU libc, atomic_ops, APR, and other system and
7813 application libraries. The hardware interface provided by LLVM should allow
7814 a clean implementation of all of these APIs and parallel programming models.
7815 No one model or paradigm should be selected above others unless the hardware
7816 itself ubiquitously does so.</p>
7817
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7818<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7819<h4>
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7820 <a name="int_memory_barrier">'<tt>llvm.memory.barrier</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7821</h4>
7822
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7823<div>
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7824<h5>Syntax:</h5>
7825<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7826 declare void @llvm.memory.barrier(i1 &lt;ll&gt;, i1 &lt;ls&gt;, i1 &lt;sl&gt;, i1 &lt;ss&gt;, i1 &lt;device&gt;)
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7827</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7828
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7829<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7830<p>The <tt>llvm.memory.barrier</tt> intrinsic guarantees ordering between
7831 specific pairs of memory access types.</p>
7832
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7833<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7834<p>The <tt>llvm.memory.barrier</tt> intrinsic requires five boolean arguments.
7835 The first four arguments enables a specific barrier as listed below. The
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]7836 fifth argument specifies that the barrier applies to io or device or uncached
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7837 memory.</p>
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7838
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7839<ul>
7840 <li><tt>ll</tt>: load-load barrier</li>
7841 <li><tt>ls</tt>: load-store barrier</li>
7842 <li><tt>sl</tt>: store-load barrier</li>
7843 <li><tt>ss</tt>: store-store barrier</li>
7844 <li><tt>device</tt>: barrier applies to device and uncached memory also.</li>
7845</ul>
7846
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7847<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7848<p>This intrinsic causes the system to enforce some ordering constraints upon
7849 the loads and stores of the program. This barrier does not
7850 indicate <em>when</em> any events will occur, it only enforces
7851 an <em>order</em> in which they occur. For any of the specified pairs of load
7852 and store operations (f.ex. load-load, or store-load), all of the first
7853 operations preceding the barrier will complete before any of the second
7854 operations succeeding the barrier begin. Specifically the semantics for each
7855 pairing is as follows:</p>
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7856
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7857<ul>
7858 <li><tt>ll</tt>: All loads before the barrier must complete before any load
7859 after the barrier begins.</li>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]7860 <li><tt>ls</tt>: All loads before the barrier must complete before any
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7861 store after the barrier begins.</li>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]7862 <li><tt>ss</tt>: All stores before the barrier must complete before any
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7863 store after the barrier begins.</li>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]7864 <li><tt>sl</tt>: All stores before the barrier must complete before any
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7865 load after the barrier begins.</li>
7866</ul>
7867
7868<p>These semantics are applied with a logical "and" behavior when more than one
7869 is enabled in a single memory barrier intrinsic.</p>
7870
7871<p>Backends may implement stronger barriers than those requested when they do
7872 not support as fine grained a barrier as requested. Some architectures do
7873 not need all types of barriers and on such architectures, these become
7874 noops.</p>
7875
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7876<h5>Example:</h5>
7877<pre>
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]7878%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7879%ptr = bitcast i8* %mallocP to i32*
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7880 store i32 4, %ptr
7881
7882%result1 = load i32* %ptr <i>; yields {i32}:result1 = 4</i>
Evan Cheng0b0669a2011-06-29 17:14:00 +0000[diff] [blame]7883 call void @llvm.memory.barrier(i1 false, i1 true, i1 false, i1 false, i1 true)
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7884 <i>; guarantee the above finishes</i>
7885 store i32 8, %ptr <i>; before this begins</i>
7886</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7887
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7888</div>
7889
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7890<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7891<h4>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7892 <a name="int_atomic_cmp_swap">'<tt>llvm.atomic.cmp.swap.*</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7893</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7894
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7895<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7896
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7897<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7898<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.cmp.swap</tt> on
7899 any integer bit width and for different address spaces. Not all targets
7900 support all bit widths however.</p>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7901
7902<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7903 declare i8 @llvm.atomic.cmp.swap.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;cmp&gt;, i8 &lt;val&gt;)
7904 declare i16 @llvm.atomic.cmp.swap.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;cmp&gt;, i16 &lt;val&gt;)
7905 declare i32 @llvm.atomic.cmp.swap.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;cmp&gt;, i32 &lt;val&gt;)
7906 declare i64 @llvm.atomic.cmp.swap.i64.p0i64(i64* &lt;ptr&gt;, i64 &lt;cmp&gt;, i64 &lt;val&gt;)
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7907</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7908
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7909<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7910<p>This loads a value in memory and compares it to a given value. If they are
7911 equal, it stores a new value into the memory.</p>
7912
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7913<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7914<p>The <tt>llvm.atomic.cmp.swap</tt> intrinsic takes three arguments. The result
7915 as well as both <tt>cmp</tt> and <tt>val</tt> must be integer values with the
7916 same bit width. The <tt>ptr</tt> argument must be a pointer to a value of
7917 this integer type. While any bit width integer may be used, targets may only
7918 lower representations they support in hardware.</p>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7919
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7920<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7921<p>This entire intrinsic must be executed atomically. It first loads the value
7922 in memory pointed to by <tt>ptr</tt> and compares it with the
7923 value <tt>cmp</tt>. If they are equal, <tt>val</tt> is stored into the
7924 memory. The loaded value is yielded in all cases. This provides the
7925 equivalent of an atomic compare-and-swap operation within the SSA
7926 framework.</p>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7927
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7928<h5>Examples:</h5>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7929<pre>
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]7930%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7931%ptr = bitcast i8* %mallocP to i32*
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7932 store i32 4, %ptr
7933
7934%val1 = add i32 4, 4
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7935%result1 = call i32 @llvm.atomic.cmp.swap.i32.p0i32(i32* %ptr, i32 4, %val1)
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7936 <i>; yields {i32}:result1 = 4</i>
7937%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
7938%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
7939
7940%val2 = add i32 1, 1
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7941%result2 = call i32 @llvm.atomic.cmp.swap.i32.p0i32(i32* %ptr, i32 5, %val2)
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7942 <i>; yields {i32}:result2 = 8</i>
7943%stored2 = icmp eq i32 %result2, 5 <i>; yields {i1}:stored2 = false</i>
7944
7945%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 8</i>
7946</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7947
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7948</div>
7949
7950<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7951<h4>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7952 <a name="int_atomic_swap">'<tt>llvm.atomic.swap.*</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7953</h4>
7954
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7955<div>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7956<h5>Syntax:</h5>
7957
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7958<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.swap</tt> on any
7959 integer bit width. Not all targets support all bit widths however.</p>
7960
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7961<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7962 declare i8 @llvm.atomic.swap.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;val&gt;)
7963 declare i16 @llvm.atomic.swap.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;val&gt;)
7964 declare i32 @llvm.atomic.swap.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;val&gt;)
7965 declare i64 @llvm.atomic.swap.i64.p0i64(i64* &lt;ptr&gt;, i64 &lt;val&gt;)
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7966</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7967
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7968<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7969<p>This intrinsic loads the value stored in memory at <tt>ptr</tt> and yields
7970 the value from memory. It then stores the value in <tt>val</tt> in the memory
7971 at <tt>ptr</tt>.</p>
7972
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7973<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7974<p>The <tt>llvm.atomic.swap</tt> intrinsic takes two arguments. Both
7975 the <tt>val</tt> argument and the result must be integers of the same bit
7976 width. The first argument, <tt>ptr</tt>, must be a pointer to a value of this
7977 integer type. The targets may only lower integer representations they
7978 support.</p>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7979
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7980<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7981<p>This intrinsic loads the value pointed to by <tt>ptr</tt>, yields it, and
7982 stores <tt>val</tt> back into <tt>ptr</tt> atomically. This provides the
7983 equivalent of an atomic swap operation within the SSA framework.</p>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7984
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7985<h5>Examples:</h5>
7986<pre>
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]7987%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7988%ptr = bitcast i8* %mallocP to i32*
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7989 store i32 4, %ptr
7990
7991%val1 = add i32 4, 4
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7992%result1 = call i32 @llvm.atomic.swap.i32.p0i32(i32* %ptr, i32 %val1)
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7993 <i>; yields {i32}:result1 = 4</i>
7994%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
7995%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
7996
7997%val2 = add i32 1, 1
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7998%result2 = call i32 @llvm.atomic.swap.i32.p0i32(i32* %ptr, i32 %val2)
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7999 <i>; yields {i32}:result2 = 8</i>
8000
8001%stored2 = icmp eq i32 %result2, 8 <i>; yields {i1}:stored2 = true</i>
8002%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 2</i>
8003</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8004
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]8005</div>
8006
8007<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8008<h4>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]8009 <a name="int_atomic_load_add">'<tt>llvm.atomic.load.add.*</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8010</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8011
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8012<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8013
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]8014<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8015<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.load.add</tt> on
8016 any integer bit width. Not all targets support all bit widths however.</p>
8017
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]8018<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]8019 declare i8 @llvm.atomic.load.add.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
8020 declare i16 @llvm.atomic.load.add.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
8021 declare i32 @llvm.atomic.load.add.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
8022 declare i64 @llvm.atomic.load.add.i64.p0i64(i64* &lt;ptr&gt;, i64 &lt;delta&gt;)
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]8023</pre>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]8024
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8025<h5>Overview:</h5>
8026<p>This intrinsic adds <tt>delta</tt> to the value stored in memory
8027 at <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.</p>
8028
8029<h5>Arguments:</h5>
8030<p>The intrinsic takes two arguments, the first a pointer to an integer value
8031 and the second an integer value. The result is also an integer value. These
8032 integer types can have any bit width, but they must all have the same bit
8033 width. The targets may only lower integer representations they support.</p>
8034
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]8035<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8036<p>This intrinsic does a series of operations atomically. It first loads the
8037 value stored at <tt>ptr</tt>. It then adds <tt>delta</tt>, stores the result
8038 to <tt>ptr</tt>. It yields the original value stored at <tt>ptr</tt>.</p>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]8039
8040<h5>Examples:</h5>
8041<pre>
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]8042%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
8043%ptr = bitcast i8* %mallocP to i32*
8044 store i32 4, %ptr
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]8045%result1 = call i32 @llvm.atomic.load.add.i32.p0i32(i32* %ptr, i32 4)
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]8046 <i>; yields {i32}:result1 = 4</i>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]8047%result2 = call i32 @llvm.atomic.load.add.i32.p0i32(i32* %ptr, i32 2)
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]8048 <i>; yields {i32}:result2 = 8</i>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]8049%result3 = call i32 @llvm.atomic.load.add.i32.p0i32(i32* %ptr, i32 5)
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]8050 <i>; yields {i32}:result3 = 10</i>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]8051%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 15</i>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]8052</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8053
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]8054</div>
8055
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]8056<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8057<h4>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]8058 <a name="int_atomic_load_sub">'<tt>llvm.atomic.load.sub.*</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8059</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8060
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8061<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8062
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]8063<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8064<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.load.sub</tt> on
8065 any integer bit width and for different address spaces. Not all targets
8066 support all bit widths however.</p>
8067
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]8068<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]8069 declare i8 @llvm.atomic.load.sub.i8.p0i32(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
8070 declare i16 @llvm.atomic.load.sub.i16.p0i32(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
8071 declare i32 @llvm.atomic.load.sub.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
8072 declare i64 @llvm.atomic.load.sub.i64.p0i32(i64* &lt;ptr&gt;, i64 &lt;delta&gt;)
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]8073</pre>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]8074
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8075<h5>Overview:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]8076<p>This intrinsic subtracts <tt>delta</tt> to the value stored in memory at
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8077 <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.</p>
8078
8079<h5>Arguments:</h5>
8080<p>The intrinsic takes two arguments, the first a pointer to an integer value
8081 and the second an integer value. The result is also an integer value. These
8082 integer types can have any bit width, but they must all have the same bit
8083 width. The targets may only lower integer representations they support.</p>
8084
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]8085<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8086<p>This intrinsic does a series of operations atomically. It first loads the
8087 value stored at <tt>ptr</tt>. It then subtracts <tt>delta</tt>, stores the
8088 result to <tt>ptr</tt>. It yields the original value stored
8089 at <tt>ptr</tt>.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]8090
8091<h5>Examples:</h5>
8092<pre>
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]8093%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
8094%ptr = bitcast i8* %mallocP to i32*
8095 store i32 8, %ptr
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]8096%result1 = call i32 @llvm.atomic.load.sub.i32.p0i32(i32* %ptr, i32 4)
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]8097 <i>; yields {i32}:result1 = 8</i>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]8098%result2 = call i32 @llvm.atomic.load.sub.i32.p0i32(i32* %ptr, i32 2)
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]8099 <i>; yields {i32}:result2 = 4</i>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]8100%result3 = call i32 @llvm.atomic.load.sub.i32.p0i32(i32* %ptr, i32 5)
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]8101 <i>; yields {i32}:result3 = 2</i>
8102%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = -3</i>
8103</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8104
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]8105</div>
8106
8107<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8108<h4>
8109 <a name="int_atomic_load_and">
8110 '<tt>llvm.atomic.load.and.*</tt>' Intrinsic
8111 </a>
8112 <br>
8113 <a name="int_atomic_load_nand">
8114 '<tt>llvm.atomic.load.nand.*</tt>' Intrinsic
8115 </a>
8116 <br>
8117 <a name="int_atomic_load_or">
8118 '<tt>llvm.atomic.load.or.*</tt>' Intrinsic
8119 </a>
8120 <br>
8121 <a name="int_atomic_load_xor">
8122 '<tt>llvm.atomic.load.xor.*</tt>' Intrinsic
8123 </a>
8124</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8125
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8126<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8127
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]8128<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8129<p>These are overloaded intrinsics. You can
8130 use <tt>llvm.atomic.load_and</tt>, <tt>llvm.atomic.load_nand</tt>,
8131 <tt>llvm.atomic.load_or</tt>, and <tt>llvm.atomic.load_xor</tt> on any integer
8132 bit width and for different address spaces. Not all targets support all bit
8133 widths however.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]8134
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8135<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]8136 declare i8 @llvm.atomic.load.and.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
8137 declare i16 @llvm.atomic.load.and.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
8138 declare i32 @llvm.atomic.load.and.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
8139 declare i64 @llvm.atomic.load.and.i64.p0i64(i64* &lt;ptr&gt;, i64 &lt;delta&gt;)
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]8140</pre>
8141
8142<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]8143 declare i8 @llvm.atomic.load.or.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
8144 declare i16 @llvm.atomic.load.or.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
8145 declare i32 @llvm.atomic.load.or.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
8146 declare i64 @llvm.atomic.load.or.i64.p0i64(i64* &lt;ptr&gt;, i64 &lt;delta&gt;)
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]8147</pre>
8148
8149<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]8150 declare i8 @llvm.atomic.load.nand.i8.p0i32(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
8151 declare i16 @llvm.atomic.load.nand.i16.p0i32(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
8152 declare i32 @llvm.atomic.load.nand.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
8153 declare i64 @llvm.atomic.load.nand.i64.p0i32(i64* &lt;ptr&gt;, i64 &lt;delta&gt;)
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]8154</pre>
8155
8156<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]8157 declare i8 @llvm.atomic.load.xor.i8.p0i32(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
8158 declare i16 @llvm.atomic.load.xor.i16.p0i32(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
8159 declare i32 @llvm.atomic.load.xor.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
8160 declare i64 @llvm.atomic.load.xor.i64.p0i32(i64* &lt;ptr&gt;, i64 &lt;delta&gt;)
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]8161</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8162
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]8163<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8164<p>These intrinsics bitwise the operation (and, nand, or, xor) <tt>delta</tt> to
8165 the value stored in memory at <tt>ptr</tt>. It yields the original value
8166 at <tt>ptr</tt>.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]8167
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8168<h5>Arguments:</h5>
8169<p>These intrinsics take two arguments, the first a pointer to an integer value
8170 and the second an integer value. The result is also an integer value. These
8171 integer types can have any bit width, but they must all have the same bit
8172 width. The targets may only lower integer representations they support.</p>
8173
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]8174<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8175<p>These intrinsics does a series of operations atomically. They first load the
8176 value stored at <tt>ptr</tt>. They then do the bitwise
8177 operation <tt>delta</tt>, store the result to <tt>ptr</tt>. They yield the
8178 original value stored at <tt>ptr</tt>.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]8179
8180<h5>Examples:</h5>
8181<pre>
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]8182%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
8183%ptr = bitcast i8* %mallocP to i32*
8184 store i32 0x0F0F, %ptr
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]8185%result0 = call i32 @llvm.atomic.load.nand.i32.p0i32(i32* %ptr, i32 0xFF)
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]8186 <i>; yields {i32}:result0 = 0x0F0F</i>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]8187%result1 = call i32 @llvm.atomic.load.and.i32.p0i32(i32* %ptr, i32 0xFF)
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]8188 <i>; yields {i32}:result1 = 0xFFFFFFF0</i>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]8189%result2 = call i32 @llvm.atomic.load.or.i32.p0i32(i32* %ptr, i32 0F)
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]8190 <i>; yields {i32}:result2 = 0xF0</i>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]8191%result3 = call i32 @llvm.atomic.load.xor.i32.p0i32(i32* %ptr, i32 0F)
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]8192 <i>; yields {i32}:result3 = FF</i>
8193%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = F0</i>
8194</pre>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]8195
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8196</div>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]8197
8198<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8199<h4>
8200 <a name="int_atomic_load_max">
8201 '<tt>llvm.atomic.load.max.*</tt>' Intrinsic
8202 </a>
8203 <br>
8204 <a name="int_atomic_load_min">
8205 '<tt>llvm.atomic.load.min.*</tt>' Intrinsic
8206 </a>
8207 <br>
8208 <a name="int_atomic_load_umax">
8209 '<tt>llvm.atomic.load.umax.*</tt>' Intrinsic
8210 </a>
8211 <br>
8212 <a name="int_atomic_load_umin">
8213 '<tt>llvm.atomic.load.umin.*</tt>' Intrinsic
8214 </a>
8215</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8216
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8217<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8218
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]8219<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8220<p>These are overloaded intrinsics. You can use <tt>llvm.atomic.load_max</tt>,
8221 <tt>llvm.atomic.load_min</tt>, <tt>llvm.atomic.load_umax</tt>, and
8222 <tt>llvm.atomic.load_umin</tt> on any integer bit width and for different
8223 address spaces. Not all targets support all bit widths however.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]8224
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8225<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]8226 declare i8 @llvm.atomic.load.max.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
8227 declare i16 @llvm.atomic.load.max.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
8228 declare i32 @llvm.atomic.load.max.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
8229 declare i64 @llvm.atomic.load.max.i64.p0i64(i64* &lt;ptr&gt;, i64 &lt;delta&gt;)
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]8230</pre>
8231
8232<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]8233 declare i8 @llvm.atomic.load.min.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
8234 declare i16 @llvm.atomic.load.min.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
8235 declare i32 @llvm.atomic.load.min.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
8236 declare i64 @llvm.atomic.load.min.i64.p0i64(i64* &lt;ptr&gt;, i64 &lt;delta&gt;)
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]8237</pre>
8238
8239<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]8240 declare i8 @llvm.atomic.load.umax.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
8241 declare i16 @llvm.atomic.load.umax.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
8242 declare i32 @llvm.atomic.load.umax.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
8243 declare i64 @llvm.atomic.load.umax.i64.p0i64(i64* &lt;ptr&gt;, i64 &lt;delta&gt;)
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]8244</pre>
8245
8246<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]8247 declare i8 @llvm.atomic.load.umin.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
8248 declare i16 @llvm.atomic.load.umin.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
8249 declare i32 @llvm.atomic.load.umin.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
8250 declare i64 @llvm.atomic.load.umin.i64.p0i64(i64* &lt;ptr&gt;, i64 &lt;delta&gt;)
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]8251</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8252
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]8253<h5>Overview:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]8254<p>These intrinsics takes the signed or unsigned minimum or maximum of
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8255 <tt>delta</tt> and the value stored in memory at <tt>ptr</tt>. It yields the
8256 original value at <tt>ptr</tt>.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]8257
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8258<h5>Arguments:</h5>
8259<p>These intrinsics take two arguments, the first a pointer to an integer value
8260 and the second an integer value. The result is also an integer value. These
8261 integer types can have any bit width, but they must all have the same bit
8262 width. The targets may only lower integer representations they support.</p>
8263
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]8264<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8265<p>These intrinsics does a series of operations atomically. They first load the
8266 value stored at <tt>ptr</tt>. They then do the signed or unsigned min or
8267 max <tt>delta</tt> and the value, store the result to <tt>ptr</tt>. They
8268 yield the original value stored at <tt>ptr</tt>.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]8269
8270<h5>Examples:</h5>
8271<pre>
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]8272%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
8273%ptr = bitcast i8* %mallocP to i32*
8274 store i32 7, %ptr
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]8275%result0 = call i32 @llvm.atomic.load.min.i32.p0i32(i32* %ptr, i32 -2)
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]8276 <i>; yields {i32}:result0 = 7</i>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]8277%result1 = call i32 @llvm.atomic.load.max.i32.p0i32(i32* %ptr, i32 8)
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]8278 <i>; yields {i32}:result1 = -2</i>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]8279%result2 = call i32 @llvm.atomic.load.umin.i32.p0i32(i32* %ptr, i32 10)
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]8280 <i>; yields {i32}:result2 = 8</i>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]8281%result3 = call i32 @llvm.atomic.load.umax.i32.p0i32(i32* %ptr, i32 30)
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]8282 <i>; yields {i32}:result3 = 8</i>
8283%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 30</i>
8284</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8285
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]8286</div>
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]8287
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8288</div>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]8289
8290<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8291<h3>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]8292 <a name="int_memorymarkers">Memory Use Markers</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8293</h3>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]8294
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8295<div>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]8296
8297<p>This class of intrinsics exists to information about the lifetime of memory
8298 objects and ranges where variables are immutable.</p>
8299
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]8300<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8301<h4>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]8302 <a name="int_lifetime_start">'<tt>llvm.lifetime.start</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8303</h4>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]8304
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8305<div>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]8306
8307<h5>Syntax:</h5>
8308<pre>
8309 declare void @llvm.lifetime.start(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
8310</pre>
8311
8312<h5>Overview:</h5>
8313<p>The '<tt>llvm.lifetime.start</tt>' intrinsic specifies the start of a memory
8314 object's lifetime.</p>
8315
8316<h5>Arguments:</h5>
Nick Lewycky321333e2009-10-13 07:57:33 +0000[diff] [blame]8317<p>The first argument is a constant integer representing the size of the
8318 object, or -1 if it is variable sized. The second argument is a pointer to
8319 the object.</p>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]8320
8321<h5>Semantics:</h5>
8322<p>This intrinsic indicates that before this point in the code, the value of the
8323 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]8324 never be used and has an undefined value. A load from the pointer that
8325 precedes this intrinsic can be replaced with
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]8326 <tt>'<a href="#undefvalues">undef</a>'</tt>.</p>
8327
8328</div>
8329
8330<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8331<h4>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]8332 <a name="int_lifetime_end">'<tt>llvm.lifetime.end</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8333</h4>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]8334
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8335<div>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]8336
8337<h5>Syntax:</h5>
8338<pre>
8339 declare void @llvm.lifetime.end(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
8340</pre>
8341
8342<h5>Overview:</h5>
8343<p>The '<tt>llvm.lifetime.end</tt>' intrinsic specifies the end of a memory
8344 object's lifetime.</p>
8345
8346<h5>Arguments:</h5>
Nick Lewycky321333e2009-10-13 07:57:33 +0000[diff] [blame]8347<p>The first argument is a constant integer representing the size of the
8348 object, or -1 if it is variable sized. The second argument is a pointer to
8349 the object.</p>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]8350
8351<h5>Semantics:</h5>
8352<p>This intrinsic indicates that after this point in the code, the value of the
8353 memory pointed to by <tt>ptr</tt> is dead. This means that it is known to
8354 never be used and has an undefined value. Any stores into the memory object
8355 following this intrinsic may be removed as dead.
8356
8357</div>
8358
8359<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8360<h4>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]8361 <a name="int_invariant_start">'<tt>llvm.invariant.start</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8362</h4>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]8363
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8364<div>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]8365
8366<h5>Syntax:</h5>
8367<pre>
Nick Lewycky29b6cb42010-11-30 04:13:41 +0000[diff] [blame]8368 declare {}* @llvm.invariant.start(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]8369</pre>
8370
8371<h5>Overview:</h5>
8372<p>The '<tt>llvm.invariant.start</tt>' intrinsic specifies that the contents of
8373 a memory object will not change.</p>
8374
8375<h5>Arguments:</h5>
Nick Lewycky321333e2009-10-13 07:57:33 +0000[diff] [blame]8376<p>The first argument is a constant integer representing the size of the
8377 object, or -1 if it is variable sized. The second argument is a pointer to
8378 the object.</p>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]8379
8380<h5>Semantics:</h5>
8381<p>This intrinsic indicates that until an <tt>llvm.invariant.end</tt> that uses
8382 the return value, the referenced memory location is constant and
8383 unchanging.</p>
8384
8385</div>
8386
8387<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8388<h4>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]8389 <a name="int_invariant_end">'<tt>llvm.invariant.end</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8390</h4>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]8391
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8392<div>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]8393
8394<h5>Syntax:</h5>
8395<pre>
8396 declare void @llvm.invariant.end({}* &lt;start&gt;, i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
8397</pre>
8398
8399<h5>Overview:</h5>
8400<p>The '<tt>llvm.invariant.end</tt>' intrinsic specifies that the contents of
8401 a memory object are mutable.</p>
8402
8403<h5>Arguments:</h5>
8404<p>The first argument is the matching <tt>llvm.invariant.start</tt> intrinsic.
Nick Lewycky321333e2009-10-13 07:57:33 +0000[diff] [blame]8405 The second argument is a constant integer representing the size of the
8406 object, or -1 if it is variable sized and the third argument is a pointer
8407 to the object.</p>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]8408
8409<h5>Semantics:</h5>
8410<p>This intrinsic indicates that the memory is mutable again.</p>
8411
8412</div>
8413
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8414</div>
8415
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]8416<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8417<h3>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]8418 <a name="int_general">General Intrinsics</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8419</h3>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]8420
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8421<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8422
8423<p>This class of intrinsics is designed to be generic and has no specific
8424 purpose.</p>
8425
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]8426<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8427<h4>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]8428 <a name="int_var_annotation">'<tt>llvm.var.annotation</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8429</h4>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]8430
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8431<div>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]8432
8433<h5>Syntax:</h5>
8434<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]8435 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]8436</pre>
8437
8438<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8439<p>The '<tt>llvm.var.annotation</tt>' intrinsic.</p>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]8440
8441<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8442<p>The first argument is a pointer to a value, the second is a pointer to a
8443 global string, the third is a pointer to a global string which is the source
8444 file name, and the last argument is the line number.</p>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]8445
8446<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8447<p>This intrinsic allows annotation of local variables with arbitrary strings.
8448 This can be useful for special purpose optimizations that want to look for
John Criswelle865c032011-08-19 16:57:55 +0000[diff] [blame]8449 these annotations. These have no other defined use; they are ignored by code
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8450 generation and optimization.</p>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]8451
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]8452</div>
8453
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]8454<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8455<h4>
Tanya Lattnere1a8da02007-09-21 23:57:59 +0000[diff] [blame]8456 <a name="int_annotation">'<tt>llvm.annotation.*</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8457</h4>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]8458
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8459<div>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]8460
8461<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8462<p>This is an overloaded intrinsic. You can use '<tt>llvm.annotation</tt>' on
8463 any integer bit width.</p>
8464
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]8465<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]8466 declare i8 @llvm.annotation.i8(i8 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
8467 declare i16 @llvm.annotation.i16(i16 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
8468 declare i32 @llvm.annotation.i32(i32 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
8469 declare i64 @llvm.annotation.i64(i64 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
8470 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]8471</pre>
8472
8473<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8474<p>The '<tt>llvm.annotation</tt>' intrinsic.</p>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]8475
8476<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8477<p>The first argument is an integer value (result of some expression), the
8478 second is a pointer to a global string, the third is a pointer to a global
8479 string which is the source file name, and the last argument is the line
8480 number. It returns the value of the first argument.</p>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]8481
8482<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8483<p>This intrinsic allows annotations to be put on arbitrary expressions with
8484 arbitrary strings. This can be useful for special purpose optimizations that
John Criswelle865c032011-08-19 16:57:55 +0000[diff] [blame]8485 want to look for these annotations. These have no other defined use; they
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8486 are ignored by code generation and optimization.</p>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]8487
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]8488</div>
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]8489
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]8490<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8491<h4>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]8492 <a name="int_trap">'<tt>llvm.trap</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8493</h4>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]8494
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8495<div>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]8496
8497<h5>Syntax:</h5>
8498<pre>
8499 declare void @llvm.trap()
8500</pre>
8501
8502<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8503<p>The '<tt>llvm.trap</tt>' intrinsic.</p>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]8504
8505<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8506<p>None.</p>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]8507
8508<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8509<p>This intrinsics is lowered to the target dependent trap instruction. If the
8510 target does not have a trap instruction, this intrinsic will be lowered to
8511 the call of the <tt>abort()</tt> function.</p>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]8512
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]8513</div>
8514
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]8515<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8516<h4>
Misha Brukmandccb0252008-11-22 23:55:29 +0000[diff] [blame]8517 <a name="int_stackprotector">'<tt>llvm.stackprotector</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8518</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8519
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8520<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8521
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]8522<h5>Syntax:</h5>
8523<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]8524 declare void @llvm.stackprotector(i8* &lt;guard&gt;, i8** &lt;slot&gt;)
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]8525</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8526
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]8527<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8528<p>The <tt>llvm.stackprotector</tt> intrinsic takes the <tt>guard</tt> and
8529 stores it onto the stack at <tt>slot</tt>. The stack slot is adjusted to
8530 ensure that it is placed on the stack before local variables.</p>
8531
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]8532<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8533<p>The <tt>llvm.stackprotector</tt> intrinsic requires two pointer
8534 arguments. The first argument is the value loaded from the stack
8535 guard <tt>@__stack_chk_guard</tt>. The second variable is an <tt>alloca</tt>
8536 that has enough space to hold the value of the guard.</p>
8537
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]8538<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8539<p>This intrinsic causes the prologue/epilogue inserter to force the position of
8540 the <tt>AllocaInst</tt> stack slot to be before local variables on the
8541 stack. This is to ensure that if a local variable on the stack is
8542 overwritten, it will destroy the value of the guard. When the function exits,
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]8543 the guard on the stack is checked against the original guard. If they are
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8544 different, then the program aborts by calling the <tt>__stack_chk_fail()</tt>
8545 function.</p>
8546
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]8547</div>
8548
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]8549<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8550<h4>
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]8551 <a name="int_objectsize">'<tt>llvm.objectsize</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8552</h4>
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]8553
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8554<div>
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]8555
8556<h5>Syntax:</h5>
8557<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]8558 declare i32 @llvm.objectsize.i32(i8* &lt;object&gt;, i1 &lt;type&gt;)
8559 declare i64 @llvm.objectsize.i64(i8* &lt;object&gt;, i1 &lt;type&gt;)
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]8560</pre>
8561
8562<h5>Overview:</h5>
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]8563<p>The <tt>llvm.objectsize</tt> intrinsic is designed to provide information to
8564 the optimizers to determine at compile time whether a) an operation (like
8565 memcpy) will overflow a buffer that corresponds to an object, or b) that a
8566 runtime check for overflow isn't necessary. An object in this context means
8567 an allocation of a specific class, structure, array, or other object.</p>
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]8568
8569<h5>Arguments:</h5>
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]8570<p>The <tt>llvm.objectsize</tt> intrinsic takes two arguments. The first
Eric Christopher8295a0a2009-12-23 00:29:49 +0000[diff] [blame]8571 argument is a pointer to or into the <tt>object</tt>. The second argument
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]8572 is a boolean 0 or 1. This argument determines whether you want the
8573 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]8574 1, variables are not allowed.</p>
8575
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]8576<h5>Semantics:</h5>
8577<p>The <tt>llvm.objectsize</tt> intrinsic is lowered to either a constant
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]8578 representing the size of the object concerned, or <tt>i32/i64 -1 or 0</tt>,
8579 depending on the <tt>type</tt> argument, if the size cannot be determined at
8580 compile time.</p>
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]8581
8582</div>
8583
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8584</div>
8585
8586</div>
8587
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]8588<!-- *********************************************************************** -->
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]8589<hr>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]8590<address>
8591 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
Misha Brukman44408702008-12-11 17:34:48 +0000[diff] [blame]8592 src="http://jigsaw.w3.org/css-validator/images/vcss-blue" alt="Valid CSS"></a>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]8593 <a href="http://validator.w3.org/check/referer"><img
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Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]8595
8596 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
NAKAMURA Takumib9a33632011-04-09 02:13:37 +0000[diff] [blame]8597 <a href="http://llvm.org/">The LLVM Compiler Infrastructure</a><br>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]8598 Last modified: $Date$
8599</address>
Chris Lattnerc7d3ab32008-01-04 04:33:49 +0000[diff] [blame]8600
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]8601</body>
8602</html>