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gerrit-public.fairphone.software / platform / external / llvm / 249d953ed7b850446fdfc600992ffb221da2f9d3 / . / docs / LangRef.html
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4<head>
5 <title>LLVM Assembly Language Reference Manual</title>
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7 <meta name="author" content="Chris Lattner">
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]8 <meta name="description"
Reid Spencer3921c742004-08-26 20:44:00 +0000[diff] [blame]9 content="LLVM Assembly Language Reference Manual.">
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]10 <link rel="stylesheet" href="llvm.css" type="text/css">
11</head>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]12
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]13<body>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]14
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]15<h1>LLVM Language Reference Manual</h1>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]16<ol>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]17 <li><a href="#abstract">Abstract</a></li>
18 <li><a href="#introduction">Introduction</a></li>
19 <li><a href="#identifiers">Identifiers</a></li>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]20 <li><a href="#highlevel">High Level Structure</a>
21 <ol>
22 <li><a href="#modulestructure">Module Structure</a></li>
Bill Wendling3d10a5a2009-07-20 01:03:30 +0000[diff] [blame]23 <li><a href="#linkage">Linkage Types</a>
24 <ol>
Bill Wendling987e7eb2009-07-20 02:41:50 +0000[diff] [blame]25 <li><a href="#linkage_private">'<tt>private</tt>' Linkage</a></li>
26 <li><a href="#linkage_linker_private">'<tt>linker_private</tt>' Linkage</a></li>
Bill Wendling5e721d72010-07-01 21:55:59 +0000[diff] [blame]27 <li><a href="#linkage_linker_private_weak">'<tt>linker_private_weak</tt>' Linkage</a></li>
Bill Wendling55ae5152010-08-20 22:05:50 +0000[diff] [blame]28 <li><a href="#linkage_linker_private_weak_def_auto">'<tt>linker_private_weak_def_auto</tt>' Linkage</a></li>
Bill Wendling987e7eb2009-07-20 02:41:50 +0000[diff] [blame]29 <li><a href="#linkage_internal">'<tt>internal</tt>' Linkage</a></li>
30 <li><a href="#linkage_available_externally">'<tt>available_externally</tt>' Linkage</a></li>
31 <li><a href="#linkage_linkonce">'<tt>linkonce</tt>' Linkage</a></li>
32 <li><a href="#linkage_common">'<tt>common</tt>' Linkage</a></li>
33 <li><a href="#linkage_weak">'<tt>weak</tt>' Linkage</a></li>
34 <li><a href="#linkage_appending">'<tt>appending</tt>' Linkage</a></li>
35 <li><a href="#linkage_externweak">'<tt>extern_weak</tt>' Linkage</a></li>
Chris Lattner5a2d8752009-10-10 18:26:06 +0000[diff] [blame]36 <li><a href="#linkage_linkonce_odr">'<tt>linkonce_odr</tt>' Linkage</a></li>
Bill Wendling987e7eb2009-07-20 02:41:50 +0000[diff] [blame]37 <li><a href="#linkage_weak">'<tt>weak_odr</tt>' Linkage</a></li>
Bill Wendlingf7f06102011-10-11 06:41:28 +0000[diff] [blame]38 <li><a href="#linkage_external">'<tt>external</tt>' Linkage</a></li>
Bill Wendling987e7eb2009-07-20 02:41:50 +0000[diff] [blame]39 <li><a href="#linkage_dllimport">'<tt>dllimport</tt>' Linkage</a></li>
40 <li><a href="#linkage_dllexport">'<tt>dllexport</tt>' Linkage</a></li>
Bill Wendling3d10a5a2009-07-20 01:03:30 +0000[diff] [blame]41 </ol>
42 </li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]43 <li><a href="#callingconv">Calling Conventions</a></li>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]44 <li><a href="#namedtypes">Named Types</a></li>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]45 <li><a href="#globalvars">Global Variables</a></li>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]46 <li><a href="#functionstructure">Functions</a></li>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]47 <li><a href="#aliasstructure">Aliases</a></li>
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]48 <li><a href="#namedmetadatastructure">Named Metadata</a></li>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]49 <li><a href="#paramattrs">Parameter Attributes</a></li>
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]50 <li><a href="#fnattrs">Function Attributes</a></li>
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]51 <li><a href="#gc">Garbage Collector Names</a></li>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]52 <li><a href="#moduleasm">Module-Level Inline Assembly</a></li>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]53 <li><a href="#datalayout">Data Layout</a></li>
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]54 <li><a href="#pointeraliasing">Pointer Aliasing Rules</a></li>
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]55 <li><a href="#volatile">Volatile Memory Accesses</a></li>
Eli Friedman5b60e1b2011-07-20 21:35:53 +0000[diff] [blame]56 <li><a href="#memmodel">Memory Model for Concurrent Operations</a></li>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]57 <li><a href="#ordering">Atomic Memory Ordering Constraints</a></li>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]58 </ol>
59 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]60 <li><a href="#typesystem">Type System</a>
61 <ol>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]62 <li><a href="#t_classifications">Type Classifications</a></li>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]63 <li><a href="#t_primitive">Primitive Types</a>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]64 <ol>
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]65 <li><a href="#t_integer">Integer Type</a></li>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]66 <li><a href="#t_floating">Floating Point Types</a></li>
Dale Johannesen21fe99b2010-10-01 00:48:59 +0000[diff] [blame]67 <li><a href="#t_x86mmx">X86mmx Type</a></li>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]68 <li><a href="#t_void">Void Type</a></li>
69 <li><a href="#t_label">Label Type</a></li>
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]70 <li><a href="#t_metadata">Metadata Type</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]71 </ol>
72 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]73 <li><a href="#t_derived">Derived Types</a>
74 <ol>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]75 <li><a href="#t_aggregate">Aggregate Types</a>
76 <ol>
77 <li><a href="#t_array">Array Type</a></li>
78 <li><a href="#t_struct">Structure Type</a></li>
Chris Lattner628ed392011-07-23 19:59:08 +0000[diff] [blame]79 <li><a href="#t_opaque">Opaque Structure Types</a></li>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]80 <li><a href="#t_vector">Vector Type</a></li>
81 </ol>
82 </li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]83 <li><a href="#t_function">Function Type</a></li>
84 <li><a href="#t_pointer">Pointer Type</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]85 </ol>
86 </li>
87 </ol>
88 </li>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]89 <li><a href="#constants">Constants</a>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]90 <ol>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]91 <li><a href="#simpleconstants">Simple Constants</a></li>
Chris Lattner70882792009-02-28 18:32:25 +0000[diff] [blame]92 <li><a href="#complexconstants">Complex Constants</a></li>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]93 <li><a href="#globalconstants">Global Variable and Function Addresses</a></li>
94 <li><a href="#undefvalues">Undefined Values</a></li>
Dan 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>
Peter Collingbourne249d9532011-10-27 19:19:07 +0000[diff] [blame^]103 <li><a href="#metadata">Metadata Nodes and Metadata Strings</a>
104 <ol>
105 <li><a href="#tbaa">'<tt>tbaa</tt>' Metadata</a></li>
106 </ol>
107 </li>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]108 </ol>
109 </li>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]110 <li><a href="#intrinsic_globals">Intrinsic Global Variables</a>
111 <ol>
112 <li><a href="#intg_used">The '<tt>llvm.used</tt>' Global Variable</a></li>
Chris Lattner401e10c2009-07-20 06:14:25 +0000[diff] [blame]113 <li><a href="#intg_compiler_used">The '<tt>llvm.compiler.used</tt>'
114 Global Variable</a></li>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]115 <li><a href="#intg_global_ctors">The '<tt>llvm.global_ctors</tt>'
116 Global Variable</a></li>
117 <li><a href="#intg_global_dtors">The '<tt>llvm.global_dtors</tt>'
118 Global Variable</a></li>
119 </ol>
120 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]121 <li><a href="#instref">Instruction Reference</a>
122 <ol>
123 <li><a href="#terminators">Terminator Instructions</a>
124 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]125 <li><a href="#i_ret">'<tt>ret</tt>' Instruction</a></li>
126 <li><a href="#i_br">'<tt>br</tt>' Instruction</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]127 <li><a href="#i_switch">'<tt>switch</tt>' Instruction</a></li>
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]128 <li><a href="#i_indirectbr">'<tt>indirectbr</tt>' Instruction</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]129 <li><a href="#i_invoke">'<tt>invoke</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]130 <li><a href="#i_unwind">'<tt>unwind</tt>' Instruction</a></li>
Bill Wendlingdccc03b2011-07-31 06:30:59 +0000[diff] [blame]131 <li><a href="#i_resume">'<tt>resume</tt>' Instruction</a></li>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]132 <li><a href="#i_unreachable">'<tt>unreachable</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]133 </ol>
134 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]135 <li><a href="#binaryops">Binary Operations</a>
136 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]137 <li><a href="#i_add">'<tt>add</tt>' Instruction</a></li>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]138 <li><a href="#i_fadd">'<tt>fadd</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]139 <li><a href="#i_sub">'<tt>sub</tt>' Instruction</a></li>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]140 <li><a href="#i_fsub">'<tt>fsub</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]141 <li><a href="#i_mul">'<tt>mul</tt>' Instruction</a></li>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]142 <li><a href="#i_fmul">'<tt>fmul</tt>' Instruction</a></li>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]143 <li><a href="#i_udiv">'<tt>udiv</tt>' Instruction</a></li>
144 <li><a href="#i_sdiv">'<tt>sdiv</tt>' Instruction</a></li>
145 <li><a href="#i_fdiv">'<tt>fdiv</tt>' Instruction</a></li>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]146 <li><a href="#i_urem">'<tt>urem</tt>' Instruction</a></li>
147 <li><a href="#i_srem">'<tt>srem</tt>' Instruction</a></li>
148 <li><a href="#i_frem">'<tt>frem</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]149 </ol>
150 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]151 <li><a href="#bitwiseops">Bitwise Binary Operations</a>
152 <ol>
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]153 <li><a href="#i_shl">'<tt>shl</tt>' Instruction</a></li>
154 <li><a href="#i_lshr">'<tt>lshr</tt>' Instruction</a></li>
155 <li><a href="#i_ashr">'<tt>ashr</tt>' Instruction</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]156 <li><a href="#i_and">'<tt>and</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]157 <li><a href="#i_or">'<tt>or</tt>' Instruction</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]158 <li><a href="#i_xor">'<tt>xor</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]159 </ol>
160 </li>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]161 <li><a href="#vectorops">Vector Operations</a>
162 <ol>
163 <li><a href="#i_extractelement">'<tt>extractelement</tt>' Instruction</a></li>
164 <li><a href="#i_insertelement">'<tt>insertelement</tt>' Instruction</a></li>
165 <li><a href="#i_shufflevector">'<tt>shufflevector</tt>' Instruction</a></li>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]166 </ol>
167 </li>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]168 <li><a href="#aggregateops">Aggregate Operations</a>
169 <ol>
170 <li><a href="#i_extractvalue">'<tt>extractvalue</tt>' Instruction</a></li>
171 <li><a href="#i_insertvalue">'<tt>insertvalue</tt>' Instruction</a></li>
172 </ol>
173 </li>
Chris Lattner884a9702006-08-15 00:45:58 +0000[diff] [blame]174 <li><a href="#memoryops">Memory Access and Addressing Operations</a>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]175 <ol>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]176 <li><a href="#i_alloca">'<tt>alloca</tt>' Instruction</a></li>
177 <li><a href="#i_load">'<tt>load</tt>' Instruction</a></li>
178 <li><a href="#i_store">'<tt>store</tt>' Instruction</a></li>
179 <li><a href="#i_fence">'<tt>fence</tt>' Instruction</a></li>
180 <li><a href="#i_cmpxchg">'<tt>cmpxchg</tt>' Instruction</a></li>
181 <li><a href="#i_atomicrmw">'<tt>atomicrmw</tt>' Instruction</a></li>
Robert Bocchino7b81c752006-02-17 21:18:08 +0000[diff] [blame]182 <li><a href="#i_getelementptr">'<tt>getelementptr</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]183 </ol>
184 </li>
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]185 <li><a href="#convertops">Conversion Operations</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]186 <ol>
187 <li><a href="#i_trunc">'<tt>trunc .. to</tt>' Instruction</a></li>
188 <li><a href="#i_zext">'<tt>zext .. to</tt>' Instruction</a></li>
189 <li><a href="#i_sext">'<tt>sext .. to</tt>' Instruction</a></li>
190 <li><a href="#i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a></li>
191 <li><a href="#i_fpext">'<tt>fpext .. to</tt>' Instruction</a></li>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]192 <li><a href="#i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a></li>
193 <li><a href="#i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a></li>
194 <li><a href="#i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a></li>
195 <li><a href="#i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a></li>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]196 <li><a href="#i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a></li>
197 <li><a href="#i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a></li>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]198 <li><a href="#i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a></li>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]199 </ol>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]200 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]201 <li><a href="#otherops">Other Operations</a>
202 <ol>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]203 <li><a href="#i_icmp">'<tt>icmp</tt>' Instruction</a></li>
204 <li><a href="#i_fcmp">'<tt>fcmp</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]205 <li><a href="#i_phi">'<tt>phi</tt>' Instruction</a></li>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]206 <li><a href="#i_select">'<tt>select</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]207 <li><a href="#i_call">'<tt>call</tt>' Instruction</a></li>
Chris Lattnerfb6977d2006-01-13 23:26:01 +0000[diff] [blame]208 <li><a href="#i_va_arg">'<tt>va_arg</tt>' Instruction</a></li>
Bill Wendlingf78faf82011-08-02 21:52:38 +0000[diff] [blame]209 <li><a href="#i_landingpad">'<tt>landingpad</tt>' Instruction</a></li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]210 </ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]211 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]212 </ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]213 </li>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]214 <li><a href="#intrinsics">Intrinsic Functions</a>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]215 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]216 <li><a href="#int_varargs">Variable Argument Handling Intrinsics</a>
217 <ol>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]218 <li><a href="#int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a></li>
219 <li><a href="#int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a></li>
220 <li><a href="#int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]221 </ol>
222 </li>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]223 <li><a href="#int_gc">Accurate Garbage Collection Intrinsics</a>
224 <ol>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]225 <li><a href="#int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a></li>
226 <li><a href="#int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a></li>
227 <li><a href="#int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a></li>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]228 </ol>
229 </li>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]230 <li><a href="#int_codegen">Code Generator Intrinsics</a>
231 <ol>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]232 <li><a href="#int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a></li>
233 <li><a href="#int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a></li>
234 <li><a href="#int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a></li>
235 <li><a href="#int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a></li>
236 <li><a href="#int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a></li>
237 <li><a href="#int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a></li>
Dan Gohman31f1af12010-05-26 21:56:15 +0000[diff] [blame]238 <li><a href="#int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a></li>
John Criswell7123e272004-04-09 16:43:20 +0000[diff] [blame]239 </ol>
240 </li>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]241 <li><a href="#int_libc">Standard C Library Intrinsics</a>
242 <ol>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]243 <li><a href="#int_memcpy">'<tt>llvm.memcpy.*</tt>' Intrinsic</a></li>
244 <li><a href="#int_memmove">'<tt>llvm.memmove.*</tt>' Intrinsic</a></li>
245 <li><a href="#int_memset">'<tt>llvm.memset.*</tt>' Intrinsic</a></li>
246 <li><a href="#int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a></li>
247 <li><a href="#int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a></li>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]248 <li><a href="#int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a></li>
249 <li><a href="#int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a></li>
250 <li><a href="#int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a></li>
Dan Gohman08b280b2011-05-27 00:36:31 +0000[diff] [blame]251 <li><a href="#int_exp">'<tt>llvm.exp.*</tt>' Intrinsic</a></li>
252 <li><a href="#int_log">'<tt>llvm.log.*</tt>' Intrinsic</a></li>
Cameron Zwarich33390842011-07-08 21:39:21 +0000[diff] [blame]253 <li><a href="#int_fma">'<tt>llvm.fma.*</tt>' Intrinsic</a></li>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]254 </ol>
255 </li>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]256 <li><a href="#int_manip">Bit Manipulation Intrinsics</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]257 <ol>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]258 <li><a href="#int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a></li>
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]259 <li><a href="#int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic </a></li>
260 <li><a href="#int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic </a></li>
261 <li><a href="#int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic </a></li>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]262 </ol>
263 </li>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]264 <li><a href="#int_overflow">Arithmetic with Overflow Intrinsics</a>
265 <ol>
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]266 <li><a href="#int_sadd_overflow">'<tt>llvm.sadd.with.overflow.*</tt> Intrinsics</a></li>
267 <li><a href="#int_uadd_overflow">'<tt>llvm.uadd.with.overflow.*</tt> Intrinsics</a></li>
268 <li><a href="#int_ssub_overflow">'<tt>llvm.ssub.with.overflow.*</tt> Intrinsics</a></li>
269 <li><a href="#int_usub_overflow">'<tt>llvm.usub.with.overflow.*</tt> Intrinsics</a></li>
270 <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]271 <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]272 </ol>
273 </li>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]274 <li><a href="#int_fp16">Half Precision Floating Point Intrinsics</a>
275 <ol>
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]276 <li><a href="#int_convert_to_fp16">'<tt>llvm.convert.to.fp16</tt>' Intrinsic</a></li>
277 <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]278 </ol>
279 </li>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]280 <li><a href="#int_debugger">Debugger intrinsics</a></li>
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]281 <li><a href="#int_eh">Exception Handling intrinsics</a></li>
Duncan Sands4a544a72011-09-06 13:37:06 +0000[diff] [blame]282 <li><a href="#int_trampoline">Trampoline Intrinsics</a>
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]283 <ol>
284 <li><a href="#int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a></li>
Duncan Sands4a544a72011-09-06 13:37:06 +0000[diff] [blame]285 <li><a href="#int_at">'<tt>llvm.adjust.trampoline</tt>' Intrinsic</a></li>
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]286 </ol>
287 </li>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]288 <li><a href="#int_memorymarkers">Memory Use Markers</a>
289 <ol>
290 <li><a href="#int_lifetime_start"><tt>llvm.lifetime.start</tt></a></li>
291 <li><a href="#int_lifetime_end"><tt>llvm.lifetime.end</tt></a></li>
292 <li><a href="#int_invariant_start"><tt>llvm.invariant.start</tt></a></li>
293 <li><a href="#int_invariant_end"><tt>llvm.invariant.end</tt></a></li>
294 </ol>
295 </li>
Reid Spencer20677642007-07-20 19:59:11 +0000[diff] [blame]296 <li><a href="#int_general">General intrinsics</a>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]297 <ol>
Reid Spencer20677642007-07-20 19:59:11 +0000[diff] [blame]298 <li><a href="#int_var_annotation">
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]299 '<tt>llvm.var.annotation</tt>' Intrinsic</a></li>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]300 <li><a href="#int_annotation">
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]301 '<tt>llvm.annotation.*</tt>' Intrinsic</a></li>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]302 <li><a href="#int_trap">
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]303 '<tt>llvm.trap</tt>' Intrinsic</a></li>
304 <li><a href="#int_stackprotector">
305 '<tt>llvm.stackprotector</tt>' Intrinsic</a></li>
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]306 <li><a href="#int_objectsize">
307 '<tt>llvm.objectsize</tt>' Intrinsic</a></li>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]308 </ol>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]309 </li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]310 </ol>
311 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]312</ol>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]313
314<div class="doc_author">
315 <p>Written by <a href="mailto:sabre@nondot.org">Chris Lattner</a>
316 and <a href="mailto:vadve@cs.uiuc.edu">Vikram Adve</a></p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]317</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]318
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]319<!-- *********************************************************************** -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]320<h2><a name="abstract">Abstract</a></h2>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]321<!-- *********************************************************************** -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]322
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]323<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]324
325<p>This document is a reference manual for the LLVM assembly language. LLVM is
326 a Static Single Assignment (SSA) based representation that provides type
327 safety, low-level operations, flexibility, and the capability of representing
328 'all' high-level languages cleanly. It is the common code representation
329 used throughout all phases of the LLVM compilation strategy.</p>
330
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]331</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]332
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]333<!-- *********************************************************************** -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]334<h2><a name="introduction">Introduction</a></h2>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]335<!-- *********************************************************************** -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]336
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]337<div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]338
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]339<p>The LLVM code representation is designed to be used in three different forms:
340 as an in-memory compiler IR, as an on-disk bitcode representation (suitable
341 for fast loading by a Just-In-Time compiler), and as a human readable
342 assembly language representation. This allows LLVM to provide a powerful
343 intermediate representation for efficient compiler transformations and
344 analysis, while providing a natural means to debug and visualize the
345 transformations. The three different forms of LLVM are all equivalent. This
346 document describes the human readable representation and notation.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]347
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]348<p>The LLVM representation aims to be light-weight and low-level while being
349 expressive, typed, and extensible at the same time. It aims to be a
350 "universal IR" of sorts, by being at a low enough level that high-level ideas
351 may be cleanly mapped to it (similar to how microprocessors are "universal
352 IR's", allowing many source languages to be mapped to them). By providing
353 type information, LLVM can be used as the target of optimizations: for
354 example, through pointer analysis, it can be proven that a C automatic
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]355 variable is never accessed outside of the current function, allowing it to
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]356 be promoted to a simple SSA value instead of a memory location.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]357
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]358<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]359<h4>
360 <a name="wellformed">Well-Formedness</a>
361</h4>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]362
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]363<div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]364
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]365<p>It is important to note that this document describes 'well formed' LLVM
366 assembly language. There is a difference between what the parser accepts and
367 what is considered 'well formed'. For example, the following instruction is
368 syntactically okay, but not well formed:</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]369
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]370<pre class="doc_code">
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]371%x = <a href="#i_add">add</a> i32 1, %x
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]372</pre>
373
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]374<p>because the definition of <tt>%x</tt> does not dominate all of its uses. The
375 LLVM infrastructure provides a verification pass that may be used to verify
376 that an LLVM module is well formed. This pass is automatically run by the
377 parser after parsing input assembly and by the optimizer before it outputs
378 bitcode. The violations pointed out by the verifier pass indicate bugs in
379 transformation passes or input to the parser.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]380
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]381</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]382
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]383</div>
384
Chris Lattnercc689392007-10-03 17:34:29 +0000[diff] [blame]385<!-- Describe the typesetting conventions here. -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]386
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]387<!-- *********************************************************************** -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]388<h2><a name="identifiers">Identifiers</a></h2>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]389<!-- *********************************************************************** -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]390
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]391<div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]392
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]393<p>LLVM identifiers come in two basic types: global and local. Global
394 identifiers (functions, global variables) begin with the <tt>'@'</tt>
395 character. Local identifiers (register names, types) begin with
396 the <tt>'%'</tt> character. Additionally, there are three different formats
397 for identifiers, for different purposes:</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]398
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]399<ol>
Reid Spencer2c452282007-08-07 14:34:28 +0000[diff] [blame]400 <li>Named values are represented as a string of characters with their prefix.
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]401 For example, <tt>%foo</tt>, <tt>@DivisionByZero</tt>,
402 <tt>%a.really.long.identifier</tt>. The actual regular expression used is
403 '<tt>[%@][a-zA-Z$._][a-zA-Z$._0-9]*</tt>'. Identifiers which require
404 other characters in their names can be surrounded with quotes. Special
405 characters may be escaped using <tt>"\xx"</tt> where <tt>xx</tt> is the
406 ASCII code for the character in hexadecimal. In this way, any character
407 can be used in a name value, even quotes themselves.</li>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]408
Reid Spencer2c452282007-08-07 14:34:28 +0000[diff] [blame]409 <li>Unnamed values are represented as an unsigned numeric value with their
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]410 prefix. For example, <tt>%12</tt>, <tt>@2</tt>, <tt>%44</tt>.</li>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]411
Reid Spencercc16dc32004-12-09 18:02:53 +0000[diff] [blame]412 <li>Constants, which are described in a <a href="#constants">section about
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]413 constants</a>, below.</li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]414</ol>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]415
Reid Spencer2c452282007-08-07 14:34:28 +0000[diff] [blame]416<p>LLVM requires that values start with a prefix for two reasons: Compilers
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]417 don't need to worry about name clashes with reserved words, and the set of
418 reserved words may be expanded in the future without penalty. Additionally,
419 unnamed identifiers allow a compiler to quickly come up with a temporary
420 variable without having to avoid symbol table conflicts.</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]421
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]422<p>Reserved words in LLVM are very similar to reserved words in other
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]423 languages. There are keywords for different opcodes
424 ('<tt><a href="#i_add">add</a></tt>',
425 '<tt><a href="#i_bitcast">bitcast</a></tt>',
426 '<tt><a href="#i_ret">ret</a></tt>', etc...), for primitive type names
427 ('<tt><a href="#t_void">void</a></tt>',
428 '<tt><a href="#t_primitive">i32</a></tt>', etc...), and others. These
429 reserved words cannot conflict with variable names, because none of them
430 start with a prefix character (<tt>'%'</tt> or <tt>'@'</tt>).</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]431
432<p>Here is an example of LLVM code to multiply the integer variable
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]433 '<tt>%X</tt>' by 8:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]434
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]435<p>The easy way:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]436
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]437<pre class="doc_code">
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]438%result = <a href="#i_mul">mul</a> i32 %X, 8
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]439</pre>
440
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]441<p>After strength reduction:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]442
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]443<pre class="doc_code">
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]444%result = <a href="#i_shl">shl</a> i32 %X, i8 3
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]445</pre>
446
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]447<p>And the hard way:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]448
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]449<pre class="doc_code">
Gabor Greifec58f752009-10-28 13:05:07 +0000[diff] [blame]450%0 = <a href="#i_add">add</a> i32 %X, %X <i>; yields {i32}:%0</i>
451%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]452%result = <a href="#i_add">add</a> i32 %1, %1
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]453</pre>
454
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]455<p>This last way of multiplying <tt>%X</tt> by 8 illustrates several important
456 lexical features of LLVM:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]457
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]458<ol>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]459 <li>Comments are delimited with a '<tt>;</tt>' and go until the end of
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]460 line.</li>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]461
462 <li>Unnamed temporaries are created when the result of a computation is not
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]463 assigned to a named value.</li>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]464
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]465 <li>Unnamed temporaries are numbered sequentially</li>
466</ol>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]467
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]468<p>It also shows a convention that we follow in this document. When
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]469 demonstrating instructions, we will follow an instruction with a comment that
470 defines the type and name of value produced. Comments are shown in italic
471 text.</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]472
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]473</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]474
475<!-- *********************************************************************** -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]476<h2><a name="highlevel">High Level Structure</a></h2>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]477<!-- *********************************************************************** -->
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]478<div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]479<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]480<h3>
481 <a name="modulestructure">Module Structure</a>
482</h3>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]483
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]484<div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]485
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]486<p>LLVM programs are composed of "Module"s, each of which is a translation unit
487 of the input programs. Each module consists of functions, global variables,
488 and symbol table entries. Modules may be combined together with the LLVM
489 linker, which merges function (and global variable) definitions, resolves
490 forward declarations, and merges symbol table entries. Here is an example of
491 the "hello world" module:</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]492
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]493<pre class="doc_code">
Chris Lattner63e4ccb2010-08-17 17:13:42 +0000[diff] [blame]494<i>; Declare the string constant as a global constant.</i>&nbsp;
Nick Lewyckydb9cd762011-01-29 01:09:53 +0000[diff] [blame]495<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]496
Chris Lattner63e4ccb2010-08-17 17:13:42 +0000[diff] [blame]497<i>; External declaration of the puts function</i>&nbsp;
498<a href="#functionstructure">declare</a> i32 @puts(i8*) <i>; i32 (i8*)* </i>&nbsp;
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]499
500<i>; Definition of main function</i>
Chris Lattner63e4ccb2010-08-17 17:13:42 +0000[diff] [blame]501define i32 @main() { <i>; i32()* </i>&nbsp;
502 <i>; Convert [13 x i8]* to i8 *...</i>&nbsp;
503 %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]504
Chris Lattner63e4ccb2010-08-17 17:13:42 +0000[diff] [blame]505 <i>; Call puts function to write out the string to stdout.</i>&nbsp;
506 <a href="#i_call">call</a> i32 @puts(i8* %cast210) <i>; i32</i>&nbsp;
507 <a href="#i_ret">ret</a> i32 0&nbsp;
508}
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]509
510<i>; Named metadata</i>
511!1 = metadata !{i32 41}
512!foo = !{!1, null}
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]513</pre>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]514
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]515<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]516 "<tt>.LC0</tt>", an external declaration of the "<tt>puts</tt>" function,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]517 a <a href="#functionstructure">function definition</a> for
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]518 "<tt>main</tt>" and <a href="#namedmetadatastructure">named metadata</a>
519 "<tt>foo"</tt>.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]520
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]521<p>In general, a module is made up of a list of global values, where both
522 functions and global variables are global values. Global values are
523 represented by a pointer to a memory location (in this case, a pointer to an
524 array of char, and a pointer to a function), and have one of the
525 following <a href="#linkage">linkage types</a>.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]526
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]527</div>
528
529<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]530<h3>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]531 <a name="linkage">Linkage Types</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]532</h3>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]533
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]534<div>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]535
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]536<p>All Global Variables and Functions have one of the following types of
537 linkage:</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]538
539<dl>
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]540 <dt><tt><b><a name="linkage_private">private</a></b></tt></dt>
Bill Wendling5e721d72010-07-01 21:55:59 +0000[diff] [blame]541 <dd>Global values with "<tt>private</tt>" linkage are only directly accessible
542 by objects in the current module. In particular, linking code into a
543 module with an private global value may cause the private to be renamed as
544 necessary to avoid collisions. Because the symbol is private to the
545 module, all references can be updated. This doesn't show up in any symbol
546 table in the object file.</dd>
Rafael Espindolabb46f522009-01-15 20:18:42 +0000[diff] [blame]547
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]548 <dt><tt><b><a name="linkage_linker_private">linker_private</a></b></tt></dt>
Bill Wendling5e721d72010-07-01 21:55:59 +0000[diff] [blame]549 <dd>Similar to <tt>private</tt>, but the symbol is passed through the
550 assembler and evaluated by the linker. Unlike normal strong symbols, they
551 are removed by the linker from the final linked image (executable or
552 dynamic library).</dd>
553
554 <dt><tt><b><a name="linkage_linker_private_weak">linker_private_weak</a></b></tt></dt>
555 <dd>Similar to "<tt>linker_private</tt>", but the symbol is weak. Note that
556 <tt>linker_private_weak</tt> symbols are subject to coalescing by the
557 linker. The symbols are removed by the linker from the final linked image
558 (executable or dynamic library).</dd>
Bill Wendling3d10a5a2009-07-20 01:03:30 +0000[diff] [blame]559
Bill Wendling55ae5152010-08-20 22:05:50 +0000[diff] [blame]560 <dt><tt><b><a name="linkage_linker_private_weak_def_auto">linker_private_weak_def_auto</a></b></tt></dt>
561 <dd>Similar to "<tt>linker_private_weak</tt>", but it's known that the address
562 of the object is not taken. For instance, functions that had an inline
563 definition, but the compiler decided not to inline it. Note,
564 unlike <tt>linker_private</tt> and <tt>linker_private_weak</tt>,
565 <tt>linker_private_weak_def_auto</tt> may have only <tt>default</tt>
566 visibility. The symbols are removed by the linker from the final linked
567 image (executable or dynamic library).</dd>
568
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]569 <dt><tt><b><a name="linkage_internal">internal</a></b></tt></dt>
Bill Wendling07d31772010-06-29 22:34:52 +0000[diff] [blame]570 <dd>Similar to private, but the value shows as a local symbol
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]571 (<tt>STB_LOCAL</tt> in the case of ELF) in the object file. This
572 corresponds to the notion of the '<tt>static</tt>' keyword in C.</dd>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]573
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]574 <dt><tt><b><a name="linkage_available_externally">available_externally</a></b></tt></dt>
Chris Lattner266c7bb2009-04-13 05:44:34 +0000[diff] [blame]575 <dd>Globals with "<tt>available_externally</tt>" linkage are never emitted
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]576 into the object file corresponding to the LLVM module. They exist to
577 allow inlining and other optimizations to take place given knowledge of
578 the definition of the global, which is known to be somewhere outside the
579 module. Globals with <tt>available_externally</tt> linkage are allowed to
580 be discarded at will, and are otherwise the same as <tt>linkonce_odr</tt>.
581 This linkage type is only allowed on definitions, not declarations.</dd>
Chris Lattner266c7bb2009-04-13 05:44:34 +0000[diff] [blame]582
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]583 <dt><tt><b><a name="linkage_linkonce">linkonce</a></b></tt></dt>
Chris Lattner4887bd82007-01-14 06:51:48 +0000[diff] [blame]584 <dd>Globals with "<tt>linkonce</tt>" linkage are merged with other globals of
Chris Lattner873187c2010-01-09 19:15:14 +0000[diff] [blame]585 the same name when linkage occurs. This can be used to implement
586 some forms of inline functions, templates, or other code which must be
587 generated in each translation unit that uses it, but where the body may
588 be overridden with a more definitive definition later. Unreferenced
589 <tt>linkonce</tt> globals are allowed to be discarded. Note that
590 <tt>linkonce</tt> linkage does not actually allow the optimizer to
591 inline the body of this function into callers because it doesn't know if
592 this definition of the function is the definitive definition within the
593 program or whether it will be overridden by a stronger definition.
594 To enable inlining and other optimizations, use "<tt>linkonce_odr</tt>"
595 linkage.</dd>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]596
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]597 <dt><tt><b><a name="linkage_weak">weak</a></b></tt></dt>
Chris Lattner26d054d2009-08-05 05:21:07 +0000[diff] [blame]598 <dd>"<tt>weak</tt>" linkage has the same merging semantics as
599 <tt>linkonce</tt> linkage, except that unreferenced globals with
600 <tt>weak</tt> linkage may not be discarded. This is used for globals that
601 are declared "weak" in C source code.</dd>
602
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]603 <dt><tt><b><a name="linkage_common">common</a></b></tt></dt>
Chris Lattner26d054d2009-08-05 05:21:07 +0000[diff] [blame]604 <dd>"<tt>common</tt>" linkage is most similar to "<tt>weak</tt>" linkage, but
605 they are used for tentative definitions in C, such as "<tt>int X;</tt>" at
606 global scope.
607 Symbols with "<tt>common</tt>" linkage are merged in the same way as
608 <tt>weak symbols</tt>, and they may not be deleted if unreferenced.
Chris Lattnercd81f5d2009-08-05 05:41:44 +0000[diff] [blame]609 <tt>common</tt> symbols may not have an explicit section,
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]610 must have a zero initializer, and may not be marked '<a
Chris Lattnercd81f5d2009-08-05 05:41:44 +0000[diff] [blame]611 href="#globalvars"><tt>constant</tt></a>'. Functions and aliases may not
612 have common linkage.</dd>
Chris Lattner26d054d2009-08-05 05:21:07 +0000[diff] [blame]613
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]614
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]615 <dt><tt><b><a name="linkage_appending">appending</a></b></tt></dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]616 <dd>"<tt>appending</tt>" linkage may only be applied to global variables of
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]617 pointer to array type. When two global variables with appending linkage
618 are linked together, the two global arrays are appended together. This is
619 the LLVM, typesafe, equivalent of having the system linker append together
620 "sections" with identical names when .o files are linked.</dd>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]621
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]622 <dt><tt><b><a name="linkage_externweak">extern_weak</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]623 <dd>The semantics of this linkage follow the ELF object file model: the symbol
624 is weak until linked, if not linked, the symbol becomes null instead of
625 being an undefined reference.</dd>
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]626
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]627 <dt><tt><b><a name="linkage_linkonce_odr">linkonce_odr</a></b></tt></dt>
628 <dt><tt><b><a name="linkage_weak_odr">weak_odr</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]629 <dd>Some languages allow differing globals to be merged, such as two functions
630 with different semantics. Other languages, such as <tt>C++</tt>, ensure
Bill Wendling5e721d72010-07-01 21:55:59 +0000[diff] [blame]631 that only equivalent globals are ever merged (the "one definition rule"
632 &mdash; "ODR"). Such languages can use the <tt>linkonce_odr</tt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]633 and <tt>weak_odr</tt> linkage types to indicate that the global will only
634 be merged with equivalent globals. These linkage types are otherwise the
635 same as their non-<tt>odr</tt> versions.</dd>
Duncan Sands667d4b82009-03-07 15:45:40 +0000[diff] [blame]636
Bill Wendlingf7f06102011-10-11 06:41:28 +0000[diff] [blame]637 <dt><tt><b><a name="linkage_external">external</a></b></tt>:</dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]638 <dd>If none of the above identifiers are used, the global is externally
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]639 visible, meaning that it participates in linkage and can be used to
640 resolve external symbol references.</dd>
Reid Spencerc8910842007-04-11 23:49:50 +0000[diff] [blame]641</dl>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]642
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]643<p>The next two types of linkage are targeted for Microsoft Windows platform
644 only. They are designed to support importing (exporting) symbols from (to)
645 DLLs (Dynamic Link Libraries).</p>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]646
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]647<dl>
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]648 <dt><tt><b><a name="linkage_dllimport">dllimport</a></b></tt></dt>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]649 <dd>"<tt>dllimport</tt>" linkage causes the compiler to reference a function
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]650 or variable via a global pointer to a pointer that is set up by the DLL
651 exporting the symbol. On Microsoft Windows targets, the pointer name is
652 formed by combining <code>__imp_</code> and the function or variable
653 name.</dd>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]654
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]655 <dt><tt><b><a name="linkage_dllexport">dllexport</a></b></tt></dt>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]656 <dd>"<tt>dllexport</tt>" linkage causes the compiler to provide a global
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]657 pointer to a pointer in a DLL, so that it can be referenced with the
658 <tt>dllimport</tt> attribute. On Microsoft Windows targets, the pointer
659 name is formed by combining <code>__imp_</code> and the function or
660 variable name.</dd>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]661</dl>
662
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]663<p>For example, since the "<tt>.LC0</tt>" variable is defined to be internal, if
664 another module defined a "<tt>.LC0</tt>" variable and was linked with this
665 one, one of the two would be renamed, preventing a collision. Since
666 "<tt>main</tt>" and "<tt>puts</tt>" are external (i.e., lacking any linkage
667 declarations), they are accessible outside of the current module.</p>
668
669<p>It is illegal for a function <i>declaration</i> to have any linkage type
Bill Wendlingf7f06102011-10-11 06:41:28 +0000[diff] [blame]670 other than <tt>external</tt>, <tt>dllimport</tt>
671 or <tt>extern_weak</tt>.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]672
Duncan Sands667d4b82009-03-07 15:45:40 +0000[diff] [blame]673<p>Aliases can have only <tt>external</tt>, <tt>internal</tt>, <tt>weak</tt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]674 or <tt>weak_odr</tt> linkages.</p>
675
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]676</div>
677
678<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]679<h3>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]680 <a name="callingconv">Calling Conventions</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]681</h3>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]682
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]683<div>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]684
685<p>LLVM <a href="#functionstructure">functions</a>, <a href="#i_call">calls</a>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]686 and <a href="#i_invoke">invokes</a> can all have an optional calling
687 convention specified for the call. The calling convention of any pair of
688 dynamic caller/callee must match, or the behavior of the program is
689 undefined. The following calling conventions are supported by LLVM, and more
690 may be added in the future:</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]691
692<dl>
693 <dt><b>"<tt>ccc</tt>" - The C calling convention</b>:</dt>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]694 <dd>This calling convention (the default if no other calling convention is
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]695 specified) matches the target C calling conventions. This calling
696 convention supports varargs function calls and tolerates some mismatch in
697 the declared prototype and implemented declaration of the function (as
698 does normal C).</dd>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]699
700 <dt><b>"<tt>fastcc</tt>" - The fast calling convention</b>:</dt>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]701 <dd>This calling convention attempts to make calls as fast as possible
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]702 (e.g. by passing things in registers). This calling convention allows the
703 target to use whatever tricks it wants to produce fast code for the
704 target, without having to conform to an externally specified ABI
Jeffrey Yasskin95fa80a2010-01-09 19:44:16 +0000[diff] [blame]705 (Application Binary Interface).
706 <a href="CodeGenerator.html#tailcallopt">Tail calls can only be optimized
Chris Lattner29689432010-03-11 00:22:57 +0000[diff] [blame]707 when this or the GHC convention is used.</a> This calling convention
708 does not support varargs and requires the prototype of all callees to
709 exactly match the prototype of the function definition.</dd>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]710
711 <dt><b>"<tt>coldcc</tt>" - The cold calling convention</b>:</dt>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]712 <dd>This calling convention attempts to make code in the caller as efficient
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]713 as possible under the assumption that the call is not commonly executed.
714 As such, these calls often preserve all registers so that the call does
715 not break any live ranges in the caller side. This calling convention
716 does not support varargs and requires the prototype of all callees to
717 exactly match the prototype of the function definition.</dd>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]718
Chris Lattner29689432010-03-11 00:22:57 +0000[diff] [blame]719 <dt><b>"<tt>cc <em>10</em></tt>" - GHC convention</b>:</dt>
720 <dd>This calling convention has been implemented specifically for use by the
721 <a href="http://www.haskell.org/ghc">Glasgow Haskell Compiler (GHC)</a>.
722 It passes everything in registers, going to extremes to achieve this by
723 disabling callee save registers. This calling convention should not be
724 used lightly but only for specific situations such as an alternative to
725 the <em>register pinning</em> performance technique often used when
726 implementing functional programming languages.At the moment only X86
727 supports this convention and it has the following limitations:
728 <ul>
729 <li>On <em>X86-32</em> only supports up to 4 bit type parameters. No
730 floating point types are supported.</li>
731 <li>On <em>X86-64</em> only supports up to 10 bit type parameters and
732 6 floating point parameters.</li>
733 </ul>
734 This calling convention supports
735 <a href="CodeGenerator.html#tailcallopt">tail call optimization</a> but
736 requires both the caller and callee are using it.
737 </dd>
738
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame]739 <dt><b>"<tt>cc &lt;<em>n</em>&gt;</tt>" - Numbered convention</b>:</dt>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]740 <dd>Any calling convention may be specified by number, allowing
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]741 target-specific calling conventions to be used. Target specific calling
742 conventions start at 64.</dd>
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame]743</dl>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]744
745<p>More calling conventions can be added/defined on an as-needed basis, to
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]746 support Pascal conventions or any other well-known target-independent
747 convention.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]748
749</div>
750
751<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]752<h3>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]753 <a name="visibility">Visibility Styles</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]754</h3>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]755
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]756<div>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]757
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]758<p>All Global Variables and Functions have one of the following visibility
759 styles:</p>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]760
761<dl>
762 <dt><b>"<tt>default</tt>" - Default style</b>:</dt>
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]763 <dd>On targets that use the ELF object file format, default visibility means
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]764 that the declaration is visible to other modules and, in shared libraries,
765 means that the declared entity may be overridden. On Darwin, default
766 visibility means that the declaration is visible to other modules. Default
767 visibility corresponds to "external linkage" in the language.</dd>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]768
769 <dt><b>"<tt>hidden</tt>" - Hidden style</b>:</dt>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]770 <dd>Two declarations of an object with hidden visibility refer to the same
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]771 object if they are in the same shared object. Usually, hidden visibility
772 indicates that the symbol will not be placed into the dynamic symbol
773 table, so no other module (executable or shared library) can reference it
774 directly.</dd>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]775
Anton Korobeynikov6f9896f2007-04-29 18:35:00 +0000[diff] [blame]776 <dt><b>"<tt>protected</tt>" - Protected style</b>:</dt>
Anton Korobeynikov6f9896f2007-04-29 18:35:00 +0000[diff] [blame]777 <dd>On ELF, protected visibility indicates that the symbol will be placed in
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]778 the dynamic symbol table, but that references within the defining module
779 will bind to the local symbol. That is, the symbol cannot be overridden by
780 another module.</dd>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]781</dl>
782
783</div>
784
785<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]786<h3>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]787 <a name="namedtypes">Named Types</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]788</h3>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]789
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]790<div>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]791
792<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]793 it easier to read the IR and make the IR more condensed (particularly when
794 recursive types are involved). An example of a name specification is:</p>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]795
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]796<pre class="doc_code">
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]797%mytype = type { %mytype*, i32 }
798</pre>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]799
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]800<p>You may give a name to any <a href="#typesystem">type</a> except
Chris Lattnerdc65f222010-08-17 23:26:04 +0000[diff] [blame]801 "<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]802 is expected with the syntax "%mytype".</p>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]803
804<p>Note that type names are aliases for the structural type that they indicate,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]805 and that you can therefore specify multiple names for the same type. This
806 often leads to confusing behavior when dumping out a .ll file. Since LLVM IR
807 uses structural typing, the name is not part of the type. When printing out
808 LLVM IR, the printer will pick <em>one name</em> to render all types of a
809 particular shape. This means that if you have code where two different
810 source types end up having the same LLVM type, that the dumper will sometimes
811 print the "wrong" or unexpected type. This is an important design point and
812 isn't going to change.</p>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]813
814</div>
815
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]816<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]817<h3>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]818 <a name="globalvars">Global Variables</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]819</h3>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]820
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]821<div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]822
Chris Lattner3689a342005-02-12 19:30:21 +0000[diff] [blame]823<p>Global variables define regions of memory allocated at compilation time
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]824 instead of run-time. Global variables may optionally be initialized, may
825 have an explicit section to be placed in, and may have an optional explicit
826 alignment specified. A variable may be defined as "thread_local", which
827 means that it will not be shared by threads (each thread will have a
828 separated copy of the variable). A variable may be defined as a global
829 "constant," which indicates that the contents of the variable
830 will <b>never</b> be modified (enabling better optimization, allowing the
831 global data to be placed in the read-only section of an executable, etc).
832 Note that variables that need runtime initialization cannot be marked
833 "constant" as there is a store to the variable.</p>
Chris Lattner3689a342005-02-12 19:30:21 +0000[diff] [blame]834
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]835<p>LLVM explicitly allows <em>declarations</em> of global variables to be marked
836 constant, even if the final definition of the global is not. This capability
837 can be used to enable slightly better optimization of the program, but
838 requires the language definition to guarantee that optimizations based on the
839 'constantness' are valid for the translation units that do not include the
840 definition.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]841
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]842<p>As SSA values, global variables define pointer values that are in scope
843 (i.e. they dominate) all basic blocks in the program. Global variables
844 always define a pointer to their "content" type because they describe a
845 region of memory, and all memory objects in LLVM are accessed through
846 pointers.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]847
Rafael Espindolabea46262011-01-08 16:42:36 +0000[diff] [blame]848<p>Global variables can be marked with <tt>unnamed_addr</tt> which indicates
849 that the address is not significant, only the content. Constants marked
Rafael Espindolaa5eaa862011-01-15 08:20:57 +0000[diff] [blame]850 like this can be merged with other constants if they have the same
851 initializer. Note that a constant with significant address <em>can</em>
852 be merged with a <tt>unnamed_addr</tt> constant, the result being a
853 constant whose address is significant.</p>
Rafael Espindolabea46262011-01-08 16:42:36 +0000[diff] [blame]854
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]855<p>A global variable may be declared to reside in a target-specific numbered
856 address space. For targets that support them, address spaces may affect how
857 optimizations are performed and/or what target instructions are used to
858 access the variable. The default address space is zero. The address space
859 qualifier must precede any other attributes.</p>
Christopher Lamb284d9922007-12-11 09:31:00 +0000[diff] [blame]860
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]861<p>LLVM allows an explicit section to be specified for globals. If the target
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]862 supports it, it will emit globals to the section specified.</p>
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]863
Chris Lattnerce99fa92010-04-28 00:13:42 +0000[diff] [blame]864<p>An explicit alignment may be specified for a global, which must be a power
865 of 2. If not present, or if the alignment is set to zero, the alignment of
866 the global is set by the target to whatever it feels convenient. If an
867 explicit alignment is specified, the global is forced to have exactly that
Chris Lattner2d4b8ee2010-04-28 00:31:12 +0000[diff] [blame]868 alignment. Targets and optimizers are not allowed to over-align the global
869 if the global has an assigned section. In this case, the extra alignment
870 could be observable: for example, code could assume that the globals are
871 densely packed in their section and try to iterate over them as an array,
872 alignment padding would break this iteration.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]873
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]874<p>For example, the following defines a global in a numbered address space with
875 an initializer, section, and alignment:</p>
Chris Lattner68027ea2007-01-14 00:27:09 +0000[diff] [blame]876
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]877<pre class="doc_code">
Dan Gohman398873c2009-01-11 00:40:00 +0000[diff] [blame]878@G = addrspace(5) constant float 1.0, section "foo", align 4
Chris Lattner68027ea2007-01-14 00:27:09 +0000[diff] [blame]879</pre>
880
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]881</div>
882
883
884<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]885<h3>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]886 <a name="functionstructure">Functions</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]887</h3>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]888
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]889<div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]890
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]891<p>LLVM function definitions consist of the "<tt>define</tt>" keyword, an
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]892 optional <a href="#linkage">linkage type</a>, an optional
893 <a href="#visibility">visibility style</a>, an optional
Rafael Espindolabea46262011-01-08 16:42:36 +0000[diff] [blame]894 <a href="#callingconv">calling convention</a>,
895 an optional <tt>unnamed_addr</tt> attribute, a return type, an optional
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]896 <a href="#paramattrs">parameter attribute</a> for the return type, a function
897 name, a (possibly empty) argument list (each with optional
898 <a href="#paramattrs">parameter attributes</a>), optional
899 <a href="#fnattrs">function attributes</a>, an optional section, an optional
900 alignment, an optional <a href="#gc">garbage collector name</a>, an opening
901 curly brace, a list of basic blocks, and a closing curly brace.</p>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]902
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]903<p>LLVM function declarations consist of the "<tt>declare</tt>" keyword, an
904 optional <a href="#linkage">linkage type</a>, an optional
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]905 <a href="#visibility">visibility style</a>, an optional
Rafael Espindolabea46262011-01-08 16:42:36 +0000[diff] [blame]906 <a href="#callingconv">calling convention</a>,
907 an optional <tt>unnamed_addr</tt> attribute, a return type, an optional
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]908 <a href="#paramattrs">parameter attribute</a> for the return type, a function
909 name, a possibly empty list of arguments, an optional alignment, and an
910 optional <a href="#gc">garbage collector name</a>.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]911
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]912<p>A function definition contains a list of basic blocks, forming the CFG
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]913 (Control Flow Graph) for the function. Each basic block may optionally start
914 with a label (giving the basic block a symbol table entry), contains a list
915 of instructions, and ends with a <a href="#terminators">terminator</a>
916 instruction (such as a branch or function return).</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]917
Chris Lattner4a3c9012007-06-08 16:52:14 +0000[diff] [blame]918<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]919 executed on entrance to the function, and it is not allowed to have
920 predecessor basic blocks (i.e. there can not be any branches to the entry
921 block of a function). Because the block can have no predecessors, it also
922 cannot have any <a href="#i_phi">PHI nodes</a>.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]923
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]924<p>LLVM allows an explicit section to be specified for functions. If the target
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]925 supports it, it will emit functions to the section specified.</p>
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]926
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]927<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]928 the alignment is set to zero, the alignment of the function is set by the
929 target to whatever it feels convenient. If an explicit alignment is
930 specified, the function is forced to have at least that much alignment. All
931 alignments must be a power of 2.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]932
Rafael Espindolabea46262011-01-08 16:42:36 +0000[diff] [blame]933<p>If the <tt>unnamed_addr</tt> attribute is given, the address is know to not
934 be significant and two identical functions can be merged</p>.
935
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]936<h5>Syntax:</h5>
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]937<pre class="doc_code">
Chris Lattner50ad45c2008-10-13 16:55:18 +0000[diff] [blame]938define [<a href="#linkage">linkage</a>] [<a href="#visibility">visibility</a>]
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]939 [<a href="#callingconv">cconv</a>] [<a href="#paramattrs">ret attrs</a>]
940 &lt;ResultType&gt; @&lt;FunctionName&gt; ([argument list])
941 [<a href="#fnattrs">fn Attrs</a>] [section "name"] [align N]
942 [<a href="#gc">gc</a>] { ... }
943</pre>
Devang Patel307e8ab2008-10-07 17:48:33 +0000[diff] [blame]944
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]945</div>
946
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]947<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]948<h3>
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]949 <a name="aliasstructure">Aliases</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]950</h3>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]951
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]952<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]953
954<p>Aliases act as "second name" for the aliasee value (which can be either
955 function, global variable, another alias or bitcast of global value). Aliases
956 may have an optional <a href="#linkage">linkage type</a>, and an
957 optional <a href="#visibility">visibility style</a>.</p>
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]958
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]959<h5>Syntax:</h5>
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]960<pre class="doc_code">
Duncan Sands0b23ac12008-09-12 20:48:21 +0000[diff] [blame]961@&lt;Name&gt; = alias [Linkage] [Visibility] &lt;AliaseeTy&gt; @&lt;Aliasee&gt;
Bill Wendlingaac388b2007-05-29 09:42:13 +0000[diff] [blame]962</pre>
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]963
964</div>
965
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]966<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]967<h3>
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]968 <a name="namedmetadatastructure">Named Metadata</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]969</h3>
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]970
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]971<div>
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]972
Chris Lattnere6a5ddd2010-01-15 21:50:19 +0000[diff] [blame]973<p>Named metadata is a collection of metadata. <a href="#metadata">Metadata
Dan Gohman872814a2010-07-21 18:54:18 +0000[diff] [blame]974 nodes</a> (but not metadata strings) are the only valid operands for
Chris Lattnere6a5ddd2010-01-15 21:50:19 +0000[diff] [blame]975 a named metadata.</p>
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]976
977<h5>Syntax:</h5>
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]978<pre class="doc_code">
Dan Gohman872814a2010-07-21 18:54:18 +0000[diff] [blame]979; Some unnamed metadata nodes, which are referenced by the named metadata.
980!0 = metadata !{metadata !"zero"}
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]981!1 = metadata !{metadata !"one"}
Dan Gohman872814a2010-07-21 18:54:18 +0000[diff] [blame]982!2 = metadata !{metadata !"two"}
Dan Gohman1005bc52010-07-13 19:48:13 +0000[diff] [blame]983; A named metadata.
Dan Gohman872814a2010-07-21 18:54:18 +0000[diff] [blame]984!name = !{!0, !1, !2}
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]985</pre>
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]986
987</div>
988
989<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]990<h3>
991 <a name="paramattrs">Parameter Attributes</a>
992</h3>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]993
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]994<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]995
996<p>The return type and each parameter of a function type may have a set of
997 <i>parameter attributes</i> associated with them. Parameter attributes are
998 used to communicate additional information about the result or parameters of
999 a function. Parameter attributes are considered to be part of the function,
1000 not of the function type, so functions with different parameter attributes
1001 can have the same function type.</p>
1002
1003<p>Parameter attributes are simple keywords that follow the type specified. If
1004 multiple parameter attributes are needed, they are space separated. For
1005 example:</p>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1006
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]1007<pre class="doc_code">
Nick Lewyckyb6a7d252009-02-15 23:06:14 +0000[diff] [blame]1008declare i32 @printf(i8* noalias nocapture, ...)
Chris Lattner66d922c2008-10-04 18:33:34 +0000[diff] [blame]1009declare i32 @atoi(i8 zeroext)
1010declare signext i8 @returns_signed_char()
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1011</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1012
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1013<p>Note that any attributes for the function result (<tt>nounwind</tt>,
1014 <tt>readonly</tt>) come immediately after the argument list.</p>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1015
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1016<p>Currently, only the following parameter attributes are defined:</p>
Chris Lattner47507de2008-01-11 06:20:47 +0000[diff] [blame]1017
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1018<dl>
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1019 <dt><tt><b>zeroext</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1020 <dd>This indicates to the code generator that the parameter or return value
Cameron Zwarichebe81732011-03-16 22:20:18 +0000[diff] [blame]1021 should be zero-extended to the extent required by the target's ABI (which
1022 is usually 32-bits, but is 8-bits for a i1 on x86-64) by the caller (for a
1023 parameter) or the callee (for a return value).</dd>
Chris Lattner47507de2008-01-11 06:20:47 +0000[diff] [blame]1024
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1025 <dt><tt><b>signext</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1026 <dd>This indicates to the code generator that the parameter or return value
Cameron Zwarich9e69ff92011-03-17 14:21:58 +0000[diff] [blame]1027 should be sign-extended to the extent required by the target's ABI (which
1028 is usually 32-bits) by the caller (for a parameter) or the callee (for a
1029 return value).</dd>
Chris Lattner47507de2008-01-11 06:20:47 +0000[diff] [blame]1030
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1031 <dt><tt><b>inreg</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1032 <dd>This indicates that this parameter or return value should be treated in a
1033 special target-dependent fashion during while emitting code for a function
1034 call or return (usually, by putting it in a register as opposed to memory,
1035 though some targets use it to distinguish between two different kinds of
1036 registers). Use of this attribute is target-specific.</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><a name="byval">byval</a></b></tt></dt>
Chris Lattnera6fd81d2010-11-20 23:49:06 +0000[diff] [blame]1039 <dd><p>This indicates that the pointer parameter should really be passed by
1040 value to the function. The attribute implies that a hidden copy of the
1041 pointee
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1042 is made between the caller and the callee, so the callee is unable to
1043 modify the value in the callee. This attribute is only valid on LLVM
1044 pointer arguments. It is generally used to pass structs and arrays by
1045 value, but is also valid on pointers to scalars. The copy is considered
1046 to belong to the caller not the callee (for example,
1047 <tt><a href="#readonly">readonly</a></tt> functions should not write to
1048 <tt>byval</tt> parameters). This is not a valid attribute for return
Chris Lattnera6fd81d2010-11-20 23:49:06 +0000[diff] [blame]1049 values.</p>
1050
1051 <p>The byval attribute also supports specifying an alignment with
1052 the align attribute. It indicates the alignment of the stack slot to
1053 form and the known alignment of the pointer specified to the call site. If
1054 the alignment is not specified, then the code generator makes a
1055 target-specific assumption.</p></dd>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1056
Dan Gohmanff235352010-07-02 23:18:08 +0000[diff] [blame]1057 <dt><tt><b><a name="sret">sret</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1058 <dd>This indicates that the pointer parameter specifies the address of a
1059 structure that is the return value of the function in the source program.
1060 This pointer must be guaranteed by the caller to be valid: loads and
1061 stores to the structure may be assumed by the callee to not to trap. This
1062 may only be applied to the first parameter. This is not a valid attribute
1063 for return values. </dd>
1064
Dan Gohmanff235352010-07-02 23:18:08 +0000[diff] [blame]1065 <dt><tt><b><a name="noalias">noalias</a></b></tt></dt>
Dan Gohman1e109622010-07-02 18:41:32 +0000[diff] [blame]1066 <dd>This indicates that pointer values
1067 <a href="#pointeraliasing"><i>based</i></a> on the argument or return
Dan Gohmanefca7f92010-07-02 23:46:54 +0000[diff] [blame]1068 value do not alias pointer values which are not <i>based</i> on it,
1069 ignoring certain "irrelevant" dependencies.
1070 For a call to the parent function, dependencies between memory
1071 references from before or after the call and from those during the call
1072 are "irrelevant" to the <tt>noalias</tt> keyword for the arguments and
1073 return value used in that call.
Dan Gohman1e109622010-07-02 18:41:32 +0000[diff] [blame]1074 The caller shares the responsibility with the callee for ensuring that
1075 these requirements are met.
1076 For further details, please see the discussion of the NoAlias response in
Dan Gohmanff70fe42010-07-06 15:26:33 +0000[diff] [blame]1077 <a href="AliasAnalysis.html#MustMayNo">alias analysis</a>.<br>
1078<br>
John McCall191d4ee2010-07-06 21:07:14 +0000[diff] [blame]1079 Note that this definition of <tt>noalias</tt> is intentionally
1080 similar to the definition of <tt>restrict</tt> in C99 for function
Chris Lattner211244a2010-07-06 20:51:35 +0000[diff] [blame]1081 arguments, though it is slightly weaker.
Dan Gohmanff70fe42010-07-06 15:26:33 +0000[diff] [blame]1082<br>
1083 For function return values, C99's <tt>restrict</tt> is not meaningful,
1084 while LLVM's <tt>noalias</tt> is.
1085 </dd>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1086
Dan Gohmanff235352010-07-02 23:18:08 +0000[diff] [blame]1087 <dt><tt><b><a name="nocapture">nocapture</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1088 <dd>This indicates that the callee does not make any copies of the pointer
1089 that outlive the callee itself. This is not a valid attribute for return
1090 values.</dd>
1091
Dan Gohmanff235352010-07-02 23:18:08 +0000[diff] [blame]1092 <dt><tt><b><a name="nest">nest</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1093 <dd>This indicates that the pointer parameter can be excised using the
1094 <a href="#int_trampoline">trampoline intrinsics</a>. This is not a valid
1095 attribute for return values.</dd>
1096</dl>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1097
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1098</div>
1099
1100<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1101<h3>
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]1102 <a name="gc">Garbage Collector Names</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1103</h3>
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]1104
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1105<div>
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]1106
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1107<p>Each function may specify a garbage collector name, which is simply a
1108 string:</p>
1109
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]1110<pre class="doc_code">
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1111define void @f() gc "name" { ... }
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1112</pre>
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]1113
1114<p>The compiler declares the supported values of <i>name</i>. Specifying a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1115 collector which will cause the compiler to alter its output in order to
1116 support the named garbage collection algorithm.</p>
1117
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]1118</div>
1119
1120<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1121<h3>
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1122 <a name="fnattrs">Function Attributes</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1123</h3>
Devang Patelf8b94812008-09-04 23:05:13 +0000[diff] [blame]1124
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1125<div>
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1126
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1127<p>Function attributes are set to communicate additional information about a
1128 function. Function attributes are considered to be part of the function, not
1129 of the function type, so functions with different parameter attributes can
1130 have the same function type.</p>
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1131
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1132<p>Function attributes are simple keywords that follow the type specified. If
1133 multiple attributes are needed, they are space separated. For example:</p>
Devang Patelf8b94812008-09-04 23:05:13 +0000[diff] [blame]1134
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]1135<pre class="doc_code">
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1136define void @f() noinline { ... }
1137define void @f() alwaysinline { ... }
1138define void @f() alwaysinline optsize { ... }
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1139define void @f() optsize { ... }
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1140</pre>
Devang Patelf8b94812008-09-04 23:05:13 +0000[diff] [blame]1141
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1142<dl>
Charles Davis1e063d12010-02-12 00:31:15 +0000[diff] [blame]1143 <dt><tt><b>alignstack(&lt;<em>n</em>&gt;)</b></tt></dt>
1144 <dd>This attribute indicates that, when emitting the prologue and epilogue,
1145 the backend should forcibly align the stack pointer. Specify the
1146 desired alignment, which must be a power of two, in parentheses.
1147
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1148 <dt><tt><b>alwaysinline</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1149 <dd>This attribute indicates that the inliner should attempt to inline this
1150 function into callers whenever possible, ignoring any active inlining size
1151 threshold for this caller.</dd>
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1152
Dan Gohman129bd562011-06-16 16:03:13 +0000[diff] [blame]1153 <dt><tt><b>nonlazybind</b></tt></dt>
1154 <dd>This attribute suppresses lazy symbol binding for the function. This
1155 may make calls to the function faster, at the cost of extra program
1156 startup time if the function is not called during program startup.</dd>
1157
Jakob Stoklund Olesen570a4a52010-02-06 01:16:28 +0000[diff] [blame]1158 <dt><tt><b>inlinehint</b></tt></dt>
1159 <dd>This attribute indicates that the source code contained a hint that inlining
1160 this function is desirable (such as the "inline" keyword in C/C++). It
1161 is just a hint; it imposes no requirements on the inliner.</dd>
1162
Nick Lewycky76ec37a2010-07-06 18:24:09 +0000[diff] [blame]1163 <dt><tt><b>naked</b></tt></dt>
1164 <dd>This attribute disables prologue / epilogue emission for the function.
1165 This can have very system-specific consequences.</dd>
1166
1167 <dt><tt><b>noimplicitfloat</b></tt></dt>
1168 <dd>This attributes disables implicit floating point instructions.</dd>
1169
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1170 <dt><tt><b>noinline</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1171 <dd>This attribute indicates that the inliner should never inline this
1172 function in any situation. This attribute may not be used together with
1173 the <tt>alwaysinline</tt> attribute.</dd>
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1174
Nick Lewycky76ec37a2010-07-06 18:24:09 +0000[diff] [blame]1175 <dt><tt><b>noredzone</b></tt></dt>
1176 <dd>This attribute indicates that the code generator should not use a red
1177 zone, even if the target-specific ABI normally permits it.</dd>
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1178
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1179 <dt><tt><b>noreturn</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1180 <dd>This function attribute indicates that the function never returns
1181 normally. This produces undefined behavior at runtime if the function
1182 ever does dynamically return.</dd>
Bill Wendling31359ba2008-11-13 01:02:51 +0000[diff] [blame]1183
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1184 <dt><tt><b>nounwind</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1185 <dd>This function attribute indicates that the function never returns with an
1186 unwind or exceptional control flow. If the function does unwind, its
1187 runtime behavior is undefined.</dd>
Bill Wendlingfbaa7ed2008-11-26 19:07:40 +0000[diff] [blame]1188
Nick Lewycky76ec37a2010-07-06 18:24:09 +0000[diff] [blame]1189 <dt><tt><b>optsize</b></tt></dt>
1190 <dd>This attribute suggests that optimization passes and code generator passes
1191 make choices that keep the code size of this function low, and otherwise
1192 do optimizations specifically to reduce code size.</dd>
1193
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1194 <dt><tt><b>readnone</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1195 <dd>This attribute indicates that the function computes its result (or decides
1196 to unwind an exception) based strictly on its arguments, without
1197 dereferencing any pointer arguments or otherwise accessing any mutable
1198 state (e.g. memory, control registers, etc) visible to caller functions.
1199 It does not write through any pointer arguments
1200 (including <tt><a href="#byval">byval</a></tt> arguments) and never
1201 changes any state visible to callers. This means that it cannot unwind
1202 exceptions by calling the <tt>C++</tt> exception throwing methods, but
1203 could use the <tt>unwind</tt> instruction.</dd>
Devang Patel5d96fda2009-06-12 19:45:19 +0000[diff] [blame]1204
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1205 <dt><tt><b><a name="readonly">readonly</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1206 <dd>This attribute indicates that the function does not write through any
1207 pointer arguments (including <tt><a href="#byval">byval</a></tt>
1208 arguments) or otherwise modify any state (e.g. memory, control registers,
1209 etc) visible to caller functions. It may dereference pointer arguments
1210 and read state that may be set in the caller. A readonly function always
1211 returns the same value (or unwinds an exception identically) when called
1212 with the same set of arguments and global state. It cannot unwind an
1213 exception by calling the <tt>C++</tt> exception throwing methods, but may
1214 use the <tt>unwind</tt> instruction.</dd>
Anton Korobeynikovc5ec8a72009-07-17 18:07:26 +0000[diff] [blame]1215
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1216 <dt><tt><b><a name="ssp">ssp</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1217 <dd>This attribute indicates that the function should emit a stack smashing
1218 protector. It is in the form of a "canary"&mdash;a random value placed on
1219 the stack before the local variables that's checked upon return from the
1220 function to see if it has been overwritten. A heuristic is used to
1221 determine if a function needs stack protectors or not.<br>
1222<br>
1223 If a function that has an <tt>ssp</tt> attribute is inlined into a
1224 function that doesn't have an <tt>ssp</tt> attribute, then the resulting
1225 function will have an <tt>ssp</tt> attribute.</dd>
1226
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1227 <dt><tt><b>sspreq</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1228 <dd>This attribute indicates that the function should <em>always</em> emit a
1229 stack smashing protector. This overrides
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1230 the <tt><a href="#ssp">ssp</a></tt> function attribute.<br>
1231<br>
1232 If a function that has an <tt>sspreq</tt> attribute is inlined into a
1233 function that doesn't have an <tt>sspreq</tt> attribute or which has
1234 an <tt>ssp</tt> attribute, then the resulting function will have
1235 an <tt>sspreq</tt> attribute.</dd>
Rafael Espindolafbff0ec2011-07-25 15:27:59 +0000[diff] [blame]1236
1237 <dt><tt><b><a name="uwtable">uwtable</a></b></tt></dt>
1238 <dd>This attribute indicates that the ABI being targeted requires that
1239 an unwind table entry be produce for this function even if we can
1240 show that no exceptions passes by it. This is normally the case for
1241 the ELF x86-64 abi, but it can be disabled for some compilation
1242 units.</dd>
1243
Rafael Espindola25456ef2011-10-03 14:45:37 +0000[diff] [blame]1244 <dt><tt><b><a name="returns_twice">returns_twice</a></b></tt></dt>
1245 <dd>This attribute indicates that this function can return
1246 twice. The C <code>setjmp</code> is an example of such a function.
1247 The compiler disables some optimizations (like tail calls) in the caller of
1248 these functions.</dd>
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1249</dl>
1250
Devang Patelf8b94812008-09-04 23:05:13 +0000[diff] [blame]1251</div>
1252
1253<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1254<h3>
Chris Lattner1eeeb0c2006-04-08 04:40:53 +0000[diff] [blame]1255 <a name="moduleasm">Module-Level Inline Assembly</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1256</h3>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1257
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1258<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1259
1260<p>Modules may contain "module-level inline asm" blocks, which corresponds to
1261 the GCC "file scope inline asm" blocks. These blocks are internally
1262 concatenated by LLVM and treated as a single unit, but may be separated in
1263 the <tt>.ll</tt> file if desired. The syntax is very simple:</p>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1264
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]1265<pre class="doc_code">
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1266module asm "inline asm code goes here"
1267module asm "more can go here"
1268</pre>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1269
1270<p>The strings can contain any character by escaping non-printable characters.
1271 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]1272 for the number.</p>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1273
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1274<p>The inline asm code is simply printed to the machine code .s file when
1275 assembly code is generated.</p>
1276
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1277</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1278
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1279<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1280<h3>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1281 <a name="datalayout">Data Layout</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1282</h3>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1283
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1284<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1285
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1286<p>A module may specify a target specific data layout string that specifies how
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1287 data is to be laid out in memory. The syntax for the data layout is
1288 simply:</p>
1289
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]1290<pre class="doc_code">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1291target datalayout = "<i>layout specification</i>"
1292</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1293
1294<p>The <i>layout specification</i> consists of a list of specifications
1295 separated by the minus sign character ('-'). Each specification starts with
1296 a letter and may include other information after the letter to define some
1297 aspect of the data layout. The specifications accepted are as follows:</p>
1298
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1299<dl>
1300 <dt><tt>E</tt></dt>
1301 <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]1302 bits with the most significance have the lowest address location.</dd>
1303
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1304 <dt><tt>e</tt></dt>
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]1305 <dd>Specifies that the target lays out data in little-endian form. That is,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1306 the bits with the least significance have the lowest address
1307 location.</dd>
1308
Lang Hamesbb5b3f32011-10-10 23:42:08 +0000[diff] [blame]1309 <dt><tt>S<i>size</i></tt></dt>
1310 <dd>Specifies the natural alignment of the stack in bits. Alignment promotion
1311 of stack variables is limited to the natural stack alignment to avoid
1312 dynamic stack realignment. The stack alignment must be a multiple of
Lang Hames5f119a62011-10-11 17:50:14 +0000[diff] [blame]1313 8-bits. If omitted, the natural stack alignment defaults to "unspecified",
1314 which does not prevent any alignment promotions.</dd>
Lang Hamesbb5b3f32011-10-10 23:42:08 +0000[diff] [blame]1315
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1316 <dt><tt>p:<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]1317 <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]1318 <i>preferred</i> alignments. All sizes are in bits. Specifying
1319 the <i>pref</i> alignment is optional. If omitted, the
1320 preceding <tt>:</tt> should be omitted too.</dd>
1321
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1322 <dt><tt>i<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1323 <dd>This specifies the alignment for an integer type of a given bit
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1324 <i>size</i>. The value of <i>size</i> must be in the range [1,2^23).</dd>
1325
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1326 <dt><tt>v<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]1327 <dd>This specifies the alignment for a vector type of a given bit
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1328 <i>size</i>.</dd>
1329
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1330 <dt><tt>f<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]1331 <dd>This specifies the alignment for a floating point type of a given bit
Dale Johannesen9d8d2212010-05-28 18:54:47 +0000[diff] [blame]1332 <i>size</i>. Only values of <i>size</i> that are supported by the target
1333 will work. 32 (float) and 64 (double) are supported on all targets;
1334 80 or 128 (different flavors of long double) are also supported on some
1335 targets.
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1336
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1337 <dt><tt>a<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1338 <dd>This specifies the alignment for an aggregate type of a given bit
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1339 <i>size</i>.</dd>
1340
Daniel Dunbar87bde0b2009-06-08 22:17:53 +0000[diff] [blame]1341 <dt><tt>s<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1342 <dd>This specifies the alignment for a stack object of a given bit
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1343 <i>size</i>.</dd>
Chris Lattnere82bdc42009-11-07 09:35:34 +0000[diff] [blame]1344
1345 <dt><tt>n<i>size1</i>:<i>size2</i>:<i>size3</i>...</tt></dt>
1346 <dd>This specifies a set of native integer widths for the target CPU
1347 in bits. For example, it might contain "n32" for 32-bit PowerPC,
1348 "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]1349 this set are considered to support most general arithmetic
Chris Lattnere82bdc42009-11-07 09:35:34 +0000[diff] [blame]1350 operations efficiently.</dd>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1351</dl>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1352
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1353<p>When constructing the data layout for a given target, LLVM starts with a
Dan Gohman1c70c002010-04-28 00:36:01 +0000[diff] [blame]1354 default set of specifications which are then (possibly) overridden by the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1355 specifications in the <tt>datalayout</tt> keyword. The default specifications
1356 are given in this list:</p>
1357
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1358<ul>
1359 <li><tt>E</tt> - big endian</li>
Dan Gohmanfdf2e8c2010-02-23 02:44:03 +0000[diff] [blame]1360 <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]1361 <li><tt>i1:8:8</tt> - i1 is 8-bit (byte) aligned</li>
1362 <li><tt>i8:8:8</tt> - i8 is 8-bit (byte) aligned</li>
1363 <li><tt>i16:16:16</tt> - i16 is 16-bit aligned</li>
1364 <li><tt>i32:32:32</tt> - i32 is 32-bit aligned</li>
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]1365 <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]1366 alignment of 64-bits</li>
1367 <li><tt>f32:32:32</tt> - float is 32-bit aligned</li>
1368 <li><tt>f64:64:64</tt> - double is 64-bit aligned</li>
1369 <li><tt>v64:64:64</tt> - 64-bit vector is 64-bit aligned</li>
1370 <li><tt>v128:128:128</tt> - 128-bit vector is 128-bit aligned</li>
1371 <li><tt>a0:0:1</tt> - aggregates are 8-bit aligned</li>
Daniel Dunbar87bde0b2009-06-08 22:17:53 +0000[diff] [blame]1372 <li><tt>s0:64:64</tt> - stack objects are 64-bit aligned</li>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1373</ul>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1374
1375<p>When LLVM is determining the alignment for a given type, it uses the
1376 following rules:</p>
1377
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1378<ol>
1379 <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]1380 specification is used.</li>
1381
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1382 <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]1383 smallest integer type that is larger than the bitwidth of the sought type
1384 is used. If none of the specifications are larger than the bitwidth then
1385 the the largest integer type is used. For example, given the default
1386 specifications above, the i7 type will use the alignment of i8 (next
1387 largest) while both i65 and i256 will use the alignment of i64 (largest
1388 specified).</li>
1389
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1390 <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]1391 largest vector type that is smaller than the sought vector type will be
1392 used as a fall back. This happens because &lt;128 x double&gt; can be
1393 implemented in terms of 64 &lt;2 x double&gt;, for example.</li>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1394</ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1395
Chris Lattner6509f502011-10-11 23:01:39 +0000[diff] [blame]1396<p>The function of the data layout string may not be what you expect. Notably,
1397 this is not a specification from the frontend of what alignment the code
1398 generator should use.</p>
1399
1400<p>Instead, if specified, the target data layout is required to match what the
1401 ultimate <em>code generator</em> expects. This string is used by the
1402 mid-level optimizers to
1403 improve code, and this only works if it matches what the ultimate code
1404 generator uses. If you would like to generate IR that does not embed this
1405 target-specific detail into the IR, then you don't have to specify the
1406 string. This will disable some optimizations that require precise layout
1407 information, but this also prevents those optimizations from introducing
1408 target specificity into the IR.</p>
1409
1410
1411
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1412</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1413
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1414<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1415<h3>
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1416 <a name="pointeraliasing">Pointer Aliasing Rules</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1417</h3>
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1418
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1419<div>
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1420
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1421<p>Any memory access must be done through a pointer value associated
Andreas Bolka99a82052009-07-27 20:37:10 +0000[diff] [blame]1422with an address range of the memory access, otherwise the behavior
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1423is undefined. Pointer values are associated with address ranges
1424according to the following rules:</p>
1425
1426<ul>
Dan Gohman1e109622010-07-02 18:41:32 +0000[diff] [blame]1427 <li>A pointer value is associated with the addresses associated with
1428 any value it is <i>based</i> on.
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1429 <li>An address of a global variable is associated with the address
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1430 range of the variable's storage.</li>
1431 <li>The result value of an allocation instruction is associated with
1432 the address range of the allocated storage.</li>
1433 <li>A null pointer in the default address-space is associated with
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1434 no address.</li>
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1435 <li>An integer constant other than zero or a pointer value returned
1436 from a function not defined within LLVM may be associated with address
1437 ranges allocated through mechanisms other than those provided by
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1438 LLVM. Such ranges shall not overlap with any ranges of addresses
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1439 allocated by mechanisms provided by LLVM.</li>
Dan Gohman1e109622010-07-02 18:41:32 +0000[diff] [blame]1440</ul>
1441
1442<p>A pointer value is <i>based</i> on another pointer value according
1443 to the following rules:</p>
1444
1445<ul>
1446 <li>A pointer value formed from a
1447 <tt><a href="#i_getelementptr">getelementptr</a></tt> operation
1448 is <i>based</i> on the first operand of the <tt>getelementptr</tt>.</li>
1449 <li>The result value of a
1450 <tt><a href="#i_bitcast">bitcast</a></tt> is <i>based</i> on the operand
1451 of the <tt>bitcast</tt>.</li>
1452 <li>A pointer value formed by an
1453 <tt><a href="#i_inttoptr">inttoptr</a></tt> is <i>based</i> on all
1454 pointer values that contribute (directly or indirectly) to the
1455 computation of the pointer's value.</li>
1456 <li>The "<i>based</i> on" relationship is transitive.</li>
1457</ul>
1458
1459<p>Note that this definition of <i>"based"</i> is intentionally
1460 similar to the definition of <i>"based"</i> in C99, though it is
1461 slightly weaker.</p>
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1462
1463<p>LLVM IR does not associate types with memory. The result type of a
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1464<tt><a href="#i_load">load</a></tt> merely indicates the size and
1465alignment of the memory from which to load, as well as the
Dan Gohmanc22c0f32010-06-17 19:23:50 +0000[diff] [blame]1466interpretation of the value. The first operand type of a
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1467<tt><a href="#i_store">store</a></tt> similarly only indicates the size
1468and alignment of the store.</p>
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1469
1470<p>Consequently, type-based alias analysis, aka TBAA, aka
1471<tt>-fstrict-aliasing</tt>, is not applicable to general unadorned
1472LLVM IR. <a href="#metadata">Metadata</a> may be used to encode
1473additional information which specialized optimization passes may use
1474to implement type-based alias analysis.</p>
1475
1476</div>
1477
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]1478<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1479<h3>
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]1480 <a name="volatile">Volatile Memory Accesses</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1481</h3>
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]1482
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1483<div>
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]1484
1485<p>Certain memory accesses, such as <a href="#i_load"><tt>load</tt></a>s, <a
1486href="#i_store"><tt>store</tt></a>s, and <a
1487href="#int_memcpy"><tt>llvm.memcpy</tt></a>s may be marked <tt>volatile</tt>.
1488The optimizers must not change the number of volatile operations or change their
1489order of execution relative to other volatile operations. The optimizers
1490<i>may</i> change the order of volatile operations relative to non-volatile
1491operations. This is not Java's "volatile" and has no cross-thread
1492synchronization behavior.</p>
1493
1494</div>
1495
Eli Friedman5b60e1b2011-07-20 21:35:53 +0000[diff] [blame]1496<!-- ======================================================================= -->
1497<h3>
1498 <a name="memmodel">Memory Model for Concurrent Operations</a>
1499</h3>
1500
1501<div>
1502
1503<p>The LLVM IR does not define any way to start parallel threads of execution
1504or to register signal handlers. Nonetheless, there are platform-specific
1505ways to create them, and we define LLVM IR's behavior in their presence. This
1506model is inspired by the C++0x memory model.</p>
1507
Eli Friedman234bccd2011-08-22 21:35:27 +0000[diff] [blame]1508<p>For a more informal introduction to this model, see the
1509<a href="Atomics.html">LLVM Atomic Instructions and Concurrency Guide</a>.
1510
Eli Friedman5b60e1b2011-07-20 21:35:53 +0000[diff] [blame]1511<p>We define a <i>happens-before</i> partial order as the least partial order
1512that</p>
1513<ul>
1514 <li>Is a superset of single-thread program order, and</li>
1515 <li>When a <i>synchronizes-with</i> <tt>b</tt>, includes an edge from
1516 <tt>a</tt> to <tt>b</tt>. <i>Synchronizes-with</i> pairs are introduced
1517 by platform-specific techniques, like pthread locks, thread
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1518 creation, thread joining, etc., and by atomic instructions.
1519 (See also <a href="#ordering">Atomic Memory Ordering Constraints</a>).
1520 </li>
Eli Friedman5b60e1b2011-07-20 21:35:53 +0000[diff] [blame]1521</ul>
1522
1523<p>Note that program order does not introduce <i>happens-before</i> edges
1524between a thread and signals executing inside that thread.</p>
1525
1526<p>Every (defined) read operation (load instructions, memcpy, atomic
1527loads/read-modify-writes, etc.) <var>R</var> reads a series of bytes written by
1528(defined) write operations (store instructions, atomic
Eli Friedman118973a2011-07-22 03:04:45 +0000[diff] [blame]1529stores/read-modify-writes, memcpy, etc.). For the purposes of this section,
1530initialized globals are considered to have a write of the initializer which is
1531atomic and happens before any other read or write of the memory in question.
1532For each byte of a read <var>R</var>, <var>R<sub>byte</sub></var> may see
1533any write to the same byte, except:</p>
Eli Friedman5b60e1b2011-07-20 21:35:53 +0000[diff] [blame]1534
1535<ul>
1536 <li>If <var>write<sub>1</sub></var> happens before
1537 <var>write<sub>2</sub></var>, and <var>write<sub>2</sub></var> happens
1538 before <var>R<sub>byte</sub></var>, then <var>R<sub>byte</sub></var>
Eli Friedman118973a2011-07-22 03:04:45 +0000[diff] [blame]1539 does not see <var>write<sub>1</sub></var>.
Bill Wendling0246bb72011-07-31 06:45:03 +0000[diff] [blame]1540 <li>If <var>R<sub>byte</sub></var> happens before
1541 <var>write<sub>3</sub></var>, then <var>R<sub>byte</sub></var> does not
1542 see <var>write<sub>3</sub></var>.
Eli Friedman5b60e1b2011-07-20 21:35:53 +0000[diff] [blame]1543</ul>
1544
1545<p>Given that definition, <var>R<sub>byte</sub></var> is defined as follows:
1546<ul>
Eli Friedman234bccd2011-08-22 21:35:27 +0000[diff] [blame]1547 <li>If <var>R</var> is volatile, the result is target-dependent. (Volatile
1548 is supposed to give guarantees which can support
1549 <code>sig_atomic_t</code> in C/C++, and may be used for accesses to
1550 addresses which do not behave like normal memory. It does not generally
1551 provide cross-thread synchronization.)
1552 <li>Otherwise, if there is no write to the same byte that happens before
Eli Friedman5b60e1b2011-07-20 21:35:53 +0000[diff] [blame]1553 <var>R<sub>byte</sub></var>, <var>R<sub>byte</sub></var> returns
1554 <tt>undef</tt> for that byte.
Eli Friedman118973a2011-07-22 03:04:45 +0000[diff] [blame]1555 <li>Otherwise, if <var>R<sub>byte</sub></var> may see exactly one write,
Eli Friedman5b60e1b2011-07-20 21:35:53 +0000[diff] [blame]1556 <var>R<sub>byte</sub></var> returns the value written by that
1557 write.</li>
Eli Friedman118973a2011-07-22 03:04:45 +0000[diff] [blame]1558 <li>Otherwise, if <var>R</var> is atomic, and all the writes
1559 <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]1560 values written. See the <a href="#ordering">Atomic Memory Ordering
1561 Constraints</a> section for additional constraints on how the choice
1562 is made.
Eli Friedman5b60e1b2011-07-20 21:35:53 +0000[diff] [blame]1563 <li>Otherwise <var>R<sub>byte</sub></var> returns <tt>undef</tt>.</li>
1564</ul>
1565
1566<p><var>R</var> returns the value composed of the series of bytes it read.
1567This implies that some bytes within the value may be <tt>undef</tt>
1568<b>without</b> the entire value being <tt>undef</tt>. Note that this only
1569defines the semantics of the operation; it doesn't mean that targets will
1570emit more than one instruction to read the series of bytes.</p>
1571
1572<p>Note that in cases where none of the atomic intrinsics are used, this model
1573places only one restriction on IR transformations on top of what is required
1574for single-threaded execution: introducing a store to a byte which might not
Eli Friedman101c81d2011-08-02 01:15:34 +0000[diff] [blame]1575otherwise be stored is not allowed in general. (Specifically, in the case
1576where another thread might write to and read from an address, introducing a
1577store can change a load that may see exactly one write into a load that may
1578see multiple writes.)</p>
Eli Friedman5b60e1b2011-07-20 21:35:53 +0000[diff] [blame]1579
1580<!-- FIXME: This model assumes all targets where concurrency is relevant have
1581a byte-size store which doesn't affect adjacent bytes. As far as I can tell,
1582none of the backends currently in the tree fall into this category; however,
1583there might be targets which care. If there are, we want a paragraph
1584like the following:
1585
1586Targets may specify that stores narrower than a certain width are not
1587available; on such a target, for the purposes of this model, treat any
1588non-atomic write with an alignment or width less than the minimum width
1589as if it writes to the relevant surrounding bytes.
1590-->
1591
1592</div>
1593
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1594<!-- ======================================================================= -->
NAKAMURA Takumib5bb29c2011-08-12 06:17:17 +0000[diff] [blame]1595<h3>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1596 <a name="ordering">Atomic Memory Ordering Constraints</a>
NAKAMURA Takumib5bb29c2011-08-12 06:17:17 +0000[diff] [blame]1597</h3>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1598
NAKAMURA Takumib5bb29c2011-08-12 06:17:17 +0000[diff] [blame]1599<div>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1600
1601<p>Atomic instructions (<a href="#i_cmpxchg"><code>cmpxchg</code></a>,
Eli Friedman21006d42011-08-09 23:02:53 +0000[diff] [blame]1602<a href="#i_atomicrmw"><code>atomicrmw</code></a>,
1603<a href="#i_fence"><code>fence</code></a>,
1604<a href="#i_load"><code>atomic load</code></a>, and
Eli Friedman8fa281a2011-08-09 23:26:12 +0000[diff] [blame]1605<a href="#i_store"><code>atomic store</code></a>) take an ordering parameter
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1606that determines which other atomic instructions on the same address they
1607<i>synchronize with</i>. These semantics are borrowed from Java and C++0x,
1608but are somewhat more colloquial. If these descriptions aren't precise enough,
Eli Friedman234bccd2011-08-22 21:35:27 +0000[diff] [blame]1609check those specs (see spec references in the
1610<a href="Atomic.html#introduction">atomics guide</a>).
1611<a href="#i_fence"><code>fence</code></a> instructions
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1612treat these orderings somewhat differently since they don't take an address.
1613See that instruction's documentation for details.</p>
1614
Eli Friedman234bccd2011-08-22 21:35:27 +0000[diff] [blame]1615<p>For a simpler introduction to the ordering constraints, see the
1616<a href="Atomics.html">LLVM Atomic Instructions and Concurrency Guide</a>.</p>
1617
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1618<dl>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1619<dt><code>unordered</code></dt>
1620<dd>The set of values that can be read is governed by the happens-before
1621partial order. A value cannot be read unless some operation wrote it.
1622This is intended to provide a guarantee strong enough to model Java's
1623non-volatile shared variables. This ordering cannot be specified for
1624read-modify-write operations; it is not strong enough to make them atomic
1625in any interesting way.</dd>
1626<dt><code>monotonic</code></dt>
1627<dd>In addition to the guarantees of <code>unordered</code>, there is a single
1628total order for modifications by <code>monotonic</code> operations on each
1629address. All modification orders must be compatible with the happens-before
1630order. There is no guarantee that the modification orders can be combined to
1631a global total order for the whole program (and this often will not be
1632possible). The read in an atomic read-modify-write operation
1633(<a href="#i_cmpxchg"><code>cmpxchg</code></a> and
1634<a href="#i_atomicrmw"><code>atomicrmw</code></a>)
1635reads the value in the modification order immediately before the value it
1636writes. If one atomic read happens before another atomic read of the same
1637address, the later read must see the same value or a later value in the
1638address's modification order. This disallows reordering of
1639<code>monotonic</code> (or stronger) operations on the same address. If an
1640address is written <code>monotonic</code>ally by one thread, and other threads
1641<code>monotonic</code>ally read that address repeatedly, the other threads must
Eli Friedman234bccd2011-08-22 21:35:27 +0000[diff] [blame]1642eventually see the write. This corresponds to the C++0x/C1x
1643<code>memory_order_relaxed</code>.</dd>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1644<dt><code>acquire</code></dt>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1645<dd>In addition to the guarantees of <code>monotonic</code>,
Eli Friedmanc264b2f2011-08-24 20:28:39 +0000[diff] [blame]1646a <i>synchronizes-with</i> edge may be formed with a <code>release</code>
1647operation. This is intended to model C++'s <code>memory_order_acquire</code>.</dd>
1648<dt><code>release</code></dt>
1649<dd>In addition to the guarantees of <code>monotonic</code>, if this operation
1650writes a value which is subsequently read by an <code>acquire</code> operation,
1651it <i>synchronizes-with</i> that operation. (This isn't a complete
1652description; see the C++0x definition of a release sequence.) This corresponds
1653to the C++0x/C1x <code>memory_order_release</code>.</dd>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1654<dt><code>acq_rel</code> (acquire+release)</dt><dd>Acts as both an
Eli Friedman234bccd2011-08-22 21:35:27 +0000[diff] [blame]1655<code>acquire</code> and <code>release</code> operation on its address.
1656This corresponds to the C++0x/C1x <code>memory_order_acq_rel</code>.</dd>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1657<dt><code>seq_cst</code> (sequentially consistent)</dt><dd>
1658<dd>In addition to the guarantees of <code>acq_rel</code>
1659(<code>acquire</code> for an operation which only reads, <code>release</code>
1660for an operation which only writes), there is a global total order on all
1661sequentially-consistent operations on all addresses, which is consistent with
1662the <i>happens-before</i> partial order and with the modification orders of
1663all the affected addresses. Each sequentially-consistent read sees the last
Eli Friedman234bccd2011-08-22 21:35:27 +0000[diff] [blame]1664preceding write to the same address in this global order. This corresponds
1665to the C++0x/C1x <code>memory_order_seq_cst</code> and Java volatile.</dd>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1666</dl>
1667
1668<p id="singlethread">If an atomic operation is marked <code>singlethread</code>,
1669it only <i>synchronizes with</i> or participates in modification and seq_cst
1670total orderings with other operations running in the same thread (for example,
1671in signal handlers).</p>
1672
1673</div>
1674
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1675</div>
1676
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1677<!-- *********************************************************************** -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1678<h2><a name="typesystem">Type System</a></h2>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1679<!-- *********************************************************************** -->
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1680
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1681<div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1682
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1683<p>The LLVM type system is one of the most important features of the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1684 intermediate representation. Being typed enables a number of optimizations
1685 to be performed on the intermediate representation directly, without having
1686 to do extra analyses on the side before the transformation. A strong type
1687 system makes it easier to read the generated code and enables novel analyses
1688 and transformations that are not feasible to perform on normal three address
1689 code representations.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1690
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1691<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1692<h3>
1693 <a name="t_classifications">Type Classifications</a>
1694</h3>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1695
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1696<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1697
1698<p>The types fall into a few useful classifications:</p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1699
1700<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1701 <tbody>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1702 <tr><th>Classification</th><th>Types</th></tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1703 <tr>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1704 <td><a href="#t_integer">integer</a></td>
Reid Spencer2b916312007-05-16 18:44:01 +0000[diff] [blame]1705 <td><tt>i1, i2, i3, ... i8, ... i16, ... i32, ... i64, ... </tt></td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1706 </tr>
1707 <tr>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1708 <td><a href="#t_floating">floating point</a></td>
1709 <td><tt>float, double, x86_fp80, fp128, ppc_fp128</tt></td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1710 </tr>
1711 <tr>
1712 <td><a name="t_firstclass">first class</a></td>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1713 <td><a href="#t_integer">integer</a>,
1714 <a href="#t_floating">floating point</a>,
1715 <a href="#t_pointer">pointer</a>,
Dan Gohman0066db62008-06-18 18:42:13 +0000[diff] [blame]1716 <a href="#t_vector">vector</a>,
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]1717 <a href="#t_struct">structure</a>,
1718 <a href="#t_array">array</a>,
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1719 <a href="#t_label">label</a>,
1720 <a href="#t_metadata">metadata</a>.
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1721 </td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1722 </tr>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1723 <tr>
1724 <td><a href="#t_primitive">primitive</a></td>
1725 <td><a href="#t_label">label</a>,
1726 <a href="#t_void">void</a>,
Tobias Grosser05387292010-12-28 20:29:31 +0000[diff] [blame]1727 <a href="#t_integer">integer</a>,
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1728 <a href="#t_floating">floating point</a>,
Dale Johannesen21fe99b2010-10-01 00:48:59 +0000[diff] [blame]1729 <a href="#t_x86mmx">x86mmx</a>,
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1730 <a href="#t_metadata">metadata</a>.</td>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1731 </tr>
1732 <tr>
1733 <td><a href="#t_derived">derived</a></td>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]1734 <td><a href="#t_array">array</a>,
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1735 <a href="#t_function">function</a>,
1736 <a href="#t_pointer">pointer</a>,
1737 <a href="#t_struct">structure</a>,
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1738 <a href="#t_vector">vector</a>,
1739 <a href="#t_opaque">opaque</a>.
Dan Gohman01ac1012008-10-14 16:32:04 +0000[diff] [blame]1740 </td>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1741 </tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1742 </tbody>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1743</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1744
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1745<p>The <a href="#t_firstclass">first class</a> types are perhaps the most
1746 important. Values of these types are the only ones which can be produced by
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]1747 instructions.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1748
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1749</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1750
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1751<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1752<h3>
1753 <a name="t_primitive">Primitive Types</a>
1754</h3>
Chris Lattner8f8c7b72008-01-04 04:34:14 +0000[diff] [blame]1755
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1756<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1757
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1758<p>The primitive types are the fundamental building blocks of the LLVM
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1759 system.</p>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1760
1761<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1762<h4>
1763 <a name="t_integer">Integer Type</a>
1764</h4>
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]1765
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1766<div>
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]1767
1768<h5>Overview:</h5>
1769<p>The integer type is a very simple type that simply specifies an arbitrary
1770 bit width for the integer type desired. Any bit width from 1 bit to
1771 2<sup>23</sup>-1 (about 8 million) can be specified.</p>
1772
1773<h5>Syntax:</h5>
1774<pre>
1775 iN
1776</pre>
1777
1778<p>The number of bits the integer will occupy is specified by the <tt>N</tt>
1779 value.</p>
1780
1781<h5>Examples:</h5>
1782<table class="layout">
1783 <tr class="layout">
1784 <td class="left"><tt>i1</tt></td>
1785 <td class="left">a single-bit integer.</td>
1786 </tr>
1787 <tr class="layout">
1788 <td class="left"><tt>i32</tt></td>
1789 <td class="left">a 32-bit integer.</td>
1790 </tr>
1791 <tr class="layout">
1792 <td class="left"><tt>i1942652</tt></td>
1793 <td class="left">a really big integer of over 1 million bits.</td>
1794 </tr>
1795</table>
1796
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]1797</div>
1798
1799<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1800<h4>
1801 <a name="t_floating">Floating Point Types</a>
1802</h4>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1803
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1804<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1805
1806<table>
1807 <tbody>
1808 <tr><th>Type</th><th>Description</th></tr>
1809 <tr><td><tt>float</tt></td><td>32-bit floating point value</td></tr>
1810 <tr><td><tt>double</tt></td><td>64-bit floating point value</td></tr>
1811 <tr><td><tt>fp128</tt></td><td>128-bit floating point value (112-bit mantissa)</td></tr>
1812 <tr><td><tt>x86_fp80</tt></td><td>80-bit floating point value (X87)</td></tr>
1813 <tr><td><tt>ppc_fp128</tt></td><td>128-bit floating point value (two 64-bits)</td></tr>
1814 </tbody>
1815</table>
1816
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1817</div>
1818
1819<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1820<h4>
1821 <a name="t_x86mmx">X86mmx Type</a>
1822</h4>
Dale Johannesen21fe99b2010-10-01 00:48:59 +0000[diff] [blame]1823
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1824<div>
Dale Johannesen21fe99b2010-10-01 00:48:59 +0000[diff] [blame]1825
1826<h5>Overview:</h5>
1827<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>
1828
1829<h5>Syntax:</h5>
1830<pre>
Dale Johannesen473a8c82010-10-01 01:07:02 +0000[diff] [blame]1831 x86mmx
Dale Johannesen21fe99b2010-10-01 00:48:59 +0000[diff] [blame]1832</pre>
1833
1834</div>
1835
1836<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1837<h4>
1838 <a name="t_void">Void Type</a>
1839</h4>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1840
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1841<div>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1842
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1843<h5>Overview:</h5>
1844<p>The void type does not represent any value and has no size.</p>
1845
1846<h5>Syntax:</h5>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1847<pre>
1848 void
1849</pre>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1850
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1851</div>
1852
1853<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1854<h4>
1855 <a name="t_label">Label Type</a>
1856</h4>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1857
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1858<div>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1859
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1860<h5>Overview:</h5>
1861<p>The label type represents code labels.</p>
1862
1863<h5>Syntax:</h5>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1864<pre>
1865 label
1866</pre>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1867
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1868</div>
1869
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1870<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1871<h4>
1872 <a name="t_metadata">Metadata Type</a>
1873</h4>
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1874
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1875<div>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1876
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1877<h5>Overview:</h5>
Nick Lewyckyc261df92009-09-27 23:27:42 +0000[diff] [blame]1878<p>The metadata type represents embedded metadata. No derived types may be
1879 created from metadata except for <a href="#t_function">function</a>
1880 arguments.
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1881
1882<h5>Syntax:</h5>
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1883<pre>
1884 metadata
1885</pre>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1886
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1887</div>
1888
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1889</div>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1890
1891<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1892<h3>
1893 <a name="t_derived">Derived Types</a>
1894</h3>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1895
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1896<div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1897
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1898<p>The real power in LLVM comes from the derived types in the system. This is
1899 what allows a programmer to represent arrays, functions, pointers, and other
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]1900 useful types. Each of these types contain one or more element types which
1901 may be a primitive type, or another derived type. For example, it is
1902 possible to have a two dimensional array, using an array as the element type
1903 of another array.</p>
Dan Gohmand8791e52009-01-24 15:58:40 +0000[diff] [blame]1904
Chris Lattner1afcace2011-07-09 17:41:24 +0000[diff] [blame]1905</div>
1906
1907
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]1908<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1909<h4>
1910 <a name="t_aggregate">Aggregate Types</a>
1911</h4>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]1912
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1913<div>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]1914
1915<p>Aggregate Types are a subset of derived types that can contain multiple
1916 member types. <a href="#t_array">Arrays</a>,
Chris Lattner61c70e92010-08-28 04:09:24 +0000[diff] [blame]1917 <a href="#t_struct">structs</a>, and <a href="#t_vector">vectors</a> are
1918 aggregate types.</p>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]1919
1920</div>
1921
Reid Spencer2b916312007-05-16 18:44:01 +0000[diff] [blame]1922<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1923<h4>
1924 <a name="t_array">Array Type</a>
1925</h4>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1926
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1927<div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1928
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1929<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1930<p>The array type is a very simple derived type that arranges elements
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1931 sequentially in memory. The array type requires a size (number of elements)
1932 and an underlying data type.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1933
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1934<h5>Syntax:</h5>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1935<pre>
1936 [&lt;# elements&gt; x &lt;elementtype&gt;]
1937</pre>
1938
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1939<p>The number of elements is a constant integer value; <tt>elementtype</tt> may
1940 be any type with a size.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1941
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1942<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1943<table class="layout">
1944 <tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1945 <td class="left"><tt>[40 x i32]</tt></td>
1946 <td class="left">Array of 40 32-bit integer values.</td>
1947 </tr>
1948 <tr class="layout">
1949 <td class="left"><tt>[41 x i32]</tt></td>
1950 <td class="left">Array of 41 32-bit integer values.</td>
1951 </tr>
1952 <tr class="layout">
1953 <td class="left"><tt>[4 x i8]</tt></td>
1954 <td class="left">Array of 4 8-bit integer values.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1955 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1956</table>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1957<p>Here are some examples of multidimensional arrays:</p>
1958<table class="layout">
1959 <tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1960 <td class="left"><tt>[3 x [4 x i32]]</tt></td>
1961 <td class="left">3x4 array of 32-bit integer values.</td>
1962 </tr>
1963 <tr class="layout">
1964 <td class="left"><tt>[12 x [10 x float]]</tt></td>
1965 <td class="left">12x10 array of single precision floating point values.</td>
1966 </tr>
1967 <tr class="layout">
1968 <td class="left"><tt>[2 x [3 x [4 x i16]]]</tt></td>
1969 <td class="left">2x3x4 array of 16-bit integer values.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1970 </tr>
1971</table>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]1972
Dan Gohman7657f6b2009-11-09 19:01:53 +0000[diff] [blame]1973<p>There is no restriction on indexing beyond the end of the array implied by
1974 a static type (though there are restrictions on indexing beyond the bounds
1975 of an allocated object in some cases). This means that single-dimension
1976 'variable sized array' addressing can be implemented in LLVM with a zero
1977 length array type. An implementation of 'pascal style arrays' in LLVM could
1978 use the type "<tt>{ i32, [0 x float]}</tt>", for example.</p>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]1979
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1980</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1981
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1982<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1983<h4>
1984 <a name="t_function">Function Type</a>
1985</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1986
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1987<div>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]1988
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1989<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1990<p>The function type can be thought of as a function signature. It consists of
1991 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]1992 function type is a first class type or a void type.</p>
Devang Patelc3fc6df2008-03-10 20:49:15 +0000[diff] [blame]1993
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1994<h5>Syntax:</h5>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]1995<pre>
Nick Lewycky51386942009-09-27 07:55:32 +0000[diff] [blame]1996 &lt;returntype&gt; (&lt;parameter list&gt;)
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]1997</pre>
1998
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]1999<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]2000 specifiers. Optionally, the parameter list may include a type <tt>...</tt>,
2001 which indicates that the function takes a variable number of arguments.
2002 Variable argument functions can access their arguments with
2003 the <a href="#int_varargs">variable argument handling intrinsic</a>
Chris Lattner0724fbd2010-03-02 06:36:51 +0000[diff] [blame]2004 functions. '<tt>&lt;returntype&gt;</tt>' is any type except
Nick Lewyckyc261df92009-09-27 23:27:42 +0000[diff] [blame]2005 <a href="#t_label">label</a>.</p>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]2006
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2007<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]2008<table class="layout">
2009 <tr class="layout">
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]2010 <td class="left"><tt>i32 (i32)</tt></td>
2011 <td class="left">function taking an <tt>i32</tt>, returning an <tt>i32</tt>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]2012 </td>
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]2013 </tr><tr class="layout">
Chris Lattner0724fbd2010-03-02 06:36:51 +0000[diff] [blame]2014 <td class="left"><tt>float&nbsp;(i16,&nbsp;i32&nbsp;*)&nbsp;*
Reid Spencerf17a0b72006-12-31 07:20:23 +0000[diff] [blame]2015 </tt></td>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]2016 <td class="left"><a href="#t_pointer">Pointer</a> to a function that takes
Chris Lattner0724fbd2010-03-02 06:36:51 +0000[diff] [blame]2017 an <tt>i16</tt> and a <a href="#t_pointer">pointer</a> to <tt>i32</tt>,
2018 returning <tt>float</tt>.
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]2019 </td>
2020 </tr><tr class="layout">
2021 <td class="left"><tt>i32 (i8*, ...)</tt></td>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]2022 <td class="left">A vararg function that takes at least one
2023 <a href="#t_pointer">pointer</a> to <tt>i8 </tt> (char in C),
2024 which returns an integer. This is the signature for <tt>printf</tt> in
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]2025 LLVM.
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]2026 </td>
Devang Patela582f402008-03-24 05:35:41 +0000[diff] [blame]2027 </tr><tr class="layout">
2028 <td class="left"><tt>{i32, i32} (i32)</tt></td>
Nick Lewycky51386942009-09-27 07:55:32 +0000[diff] [blame]2029 <td class="left">A function taking an <tt>i32</tt>, returning a
2030 <a href="#t_struct">structure</a> containing two <tt>i32</tt> values
Devang Patela582f402008-03-24 05:35:41 +0000[diff] [blame]2031 </td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]2032 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2033</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]2034
Misha Brukman9d0919f2003-11-08 01:05:38 +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<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2038<h4>
2039 <a name="t_struct">Structure Type</a>
2040</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2041
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2042<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2043
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2044<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2045<p>The structure type is used to represent a collection of data members together
Chris Lattner1afcace2011-07-09 17:41:24 +0000[diff] [blame]2046 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]2047
Jeffrey Yasskin7a088cf2010-01-11 19:19:26 +0000[diff] [blame]2048<p>Structures in memory are accessed using '<tt><a href="#i_load">load</a></tt>'
2049 and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a field
2050 with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.
2051 Structures in registers are accessed using the
2052 '<tt><a href="#i_extractvalue">extractvalue</a></tt>' and
2053 '<tt><a href="#i_insertvalue">insertvalue</a></tt>' instructions.</p>
Chris Lattner1afcace2011-07-09 17:41:24 +0000[diff] [blame]2054
2055<p>Structures may optionally be "packed" structures, which indicate that the
2056 alignment of the struct is one byte, and that there is no padding between
Chris Lattner2c38d652011-08-12 17:31:02 +0000[diff] [blame]2057 the elements. In non-packed structs, padding between field types is inserted
2058 as defined by the TargetData string in the module, which is required to match
Chris Lattnere4617b02011-10-11 23:02:17 +0000[diff] [blame]2059 what the underlying code generator expects.</p>
Chris Lattner1afcace2011-07-09 17:41:24 +0000[diff] [blame]2060
Chris Lattner2c38d652011-08-12 17:31:02 +0000[diff] [blame]2061<p>Structures can either be "literal" or "identified". A literal structure is
2062 defined inline with other types (e.g. <tt>{i32, i32}*</tt>) whereas identified
2063 types are always defined at the top level with a name. Literal types are
2064 uniqued by their contents and can never be recursive or opaque since there is
Chris Lattneraa175c32011-08-12 18:12:40 +0000[diff] [blame]2065 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]2066 never uniqued.
Chris Lattner1afcace2011-07-09 17:41:24 +0000[diff] [blame]2067</p>
2068
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2069<h5>Syntax:</h5>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]2070<pre>
Chris Lattner2c38d652011-08-12 17:31:02 +0000[diff] [blame]2071 %T1 = type { &lt;type list&gt; } <i>; Identified normal struct type</i>
2072 %T2 = type &lt;{ &lt;type list&gt; }&gt; <i>; Identified packed struct type</i>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]2073</pre>
Chris Lattner1afcace2011-07-09 17:41:24 +0000[diff] [blame]2074
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2075<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]2076<table class="layout">
2077 <tr class="layout">
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]2078 <td class="left"><tt>{ i32, i32, i32 }</tt></td>
2079 <td class="left">A triple of three <tt>i32</tt> values</td>
Chris Lattner1afcace2011-07-09 17:41:24 +0000[diff] [blame]2080 </tr>
2081 <tr class="layout">
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]2082 <td class="left"><tt>{&nbsp;float,&nbsp;i32&nbsp;(i32)&nbsp;*&nbsp;}</tt></td>
2083 <td class="left">A pair, where the first element is a <tt>float</tt> and the
2084 second element is a <a href="#t_pointer">pointer</a> to a
2085 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
2086 an <tt>i32</tt>.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]2087 </tr>
Chris Lattner1afcace2011-07-09 17:41:24 +0000[diff] [blame]2088 <tr class="layout">
2089 <td class="left"><tt>&lt;{ i8, i32 }&gt;</tt></td>
2090 <td class="left">A packed struct known to be 5 bytes in size.</td>
2091 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2092</table>
Dan Gohmand8791e52009-01-24 15:58:40 +0000[diff] [blame]2093
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2094</div>
Chris Lattner1afcace2011-07-09 17:41:24 +0000[diff] [blame]2095
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2096<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2097<h4>
Chris Lattner628ed392011-07-23 19:59:08 +0000[diff] [blame]2098 <a name="t_opaque">Opaque Structure Types</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2099</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2100
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2101<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2102
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]2103<h5>Overview:</h5>
Chris Lattner628ed392011-07-23 19:59:08 +0000[diff] [blame]2104<p>Opaque structure types are used to represent named structure types that do
2105 not have a body specified. This corresponds (for example) to the C notion of
2106 a forward declared structure.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2107
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]2108<h5>Syntax:</h5>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]2109<pre>
Chris Lattner1afcace2011-07-09 17:41:24 +0000[diff] [blame]2110 %X = type opaque
2111 %52 = type opaque
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]2112</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2113
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]2114<h5>Examples:</h5>
2115<table class="layout">
2116 <tr class="layout">
Chris Lattner1afcace2011-07-09 17:41:24 +0000[diff] [blame]2117 <td class="left"><tt>opaque</tt></td>
2118 <td class="left">An opaque type.</td>
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]2119 </tr>
2120</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2121
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]2122</div>
2123
Chris Lattner1afcace2011-07-09 17:41:24 +0000[diff] [blame]2124
2125
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]2126<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2127<h4>
2128 <a name="t_pointer">Pointer Type</a>
2129</h4>
Chris Lattner0fd4a272009-02-08 19:53:29 +0000[diff] [blame]2130
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2131<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2132
2133<h5>Overview:</h5>
Dan Gohmanff3ef322010-02-25 16:50:07 +0000[diff] [blame]2134<p>The pointer type is used to specify memory locations.
2135 Pointers are commonly used to reference objects in memory.</p>
2136
2137<p>Pointer types may have an optional address space attribute defining the
2138 numbered address space where the pointed-to object resides. The default
2139 address space is number zero. The semantics of non-zero address
2140 spaces are target-specific.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2141
2142<p>Note that LLVM does not permit pointers to void (<tt>void*</tt>) nor does it
2143 permit pointers to labels (<tt>label*</tt>). Use <tt>i8*</tt> instead.</p>
Chris Lattner0fd4a272009-02-08 19:53:29 +0000[diff] [blame]2144
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2145<h5>Syntax:</h5>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]2146<pre>
2147 &lt;type&gt; *
2148</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2149
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2150<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]2151<table class="layout">
2152 <tr class="layout">
Dan Gohman2a08c532009-01-04 23:44:43 +0000[diff] [blame]2153 <td class="left"><tt>[4 x i32]*</tt></td>
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]2154 <td class="left">A <a href="#t_pointer">pointer</a> to <a
2155 href="#t_array">array</a> of four <tt>i32</tt> values.</td>
2156 </tr>
2157 <tr class="layout">
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]2158 <td class="left"><tt>i32 (i32*) *</tt></td>
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]2159 <td class="left"> A <a href="#t_pointer">pointer</a> to a <a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2160 href="#t_function">function</a> that takes an <tt>i32*</tt>, returning an
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]2161 <tt>i32</tt>.</td>
2162 </tr>
2163 <tr class="layout">
2164 <td class="left"><tt>i32 addrspace(5)*</tt></td>
2165 <td class="left">A <a href="#t_pointer">pointer</a> to an <tt>i32</tt> value
2166 that resides in address space #5.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]2167 </tr>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2168</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2169
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2170</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]2171
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]2172<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2173<h4>
2174 <a name="t_vector">Vector Type</a>
2175</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2176
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2177<div>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]2178
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]2179<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2180<p>A vector type is a simple derived type that represents a vector of elements.
2181 Vector types are used when multiple primitive data are operated in parallel
2182 using a single instruction (SIMD). A vector type requires a size (number of
Duncan Sandsd40d14e2009-11-27 13:38:03 +0000[diff] [blame]2183 elements) and an underlying primitive data type. Vector types are considered
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2184 <a href="#t_firstclass">first class</a>.</p>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]2185
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]2186<h5>Syntax:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]2187<pre>
2188 &lt; &lt;# elements&gt; x &lt;elementtype&gt; &gt;
2189</pre>
2190
Chris Lattner7d2e7be2010-10-10 18:20:35 +0000[diff] [blame]2191<p>The number of elements is a constant integer value larger than 0; elementtype
2192 may be any integer or floating point type. Vectors of size zero are not
2193 allowed, and pointers are not allowed as the element type.</p>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]2194
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]2195<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]2196<table class="layout">
2197 <tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]2198 <td class="left"><tt>&lt;4 x i32&gt;</tt></td>
2199 <td class="left">Vector of 4 32-bit integer values.</td>
2200 </tr>
2201 <tr class="layout">
2202 <td class="left"><tt>&lt;8 x float&gt;</tt></td>
2203 <td class="left">Vector of 8 32-bit floating-point values.</td>
2204 </tr>
2205 <tr class="layout">
2206 <td class="left"><tt>&lt;2 x i64&gt;</tt></td>
2207 <td class="left">Vector of 2 64-bit integer values.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]2208 </tr>
2209</table>
Dan Gohmand8791e52009-01-24 15:58:40 +0000[diff] [blame]2210
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2211</div>
2212
Bill Wendlingaf75f0c2011-07-31 06:47:33 +0000[diff] [blame]2213</div>
2214
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2215<!-- *********************************************************************** -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2216<h2><a name="constants">Constants</a></h2>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2217<!-- *********************************************************************** -->
2218
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2219<div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2220
2221<p>LLVM has several different basic types of constants. This section describes
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2222 them all and their syntax.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2223
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2224<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2225<h3>
2226 <a name="simpleconstants">Simple Constants</a>
2227</h3>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2228
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2229<div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2230
2231<dl>
2232 <dt><b>Boolean constants</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2233 <dd>The two strings '<tt>true</tt>' and '<tt>false</tt>' are both valid
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]2234 constants of the <tt><a href="#t_integer">i1</a></tt> type.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2235
2236 <dt><b>Integer constants</b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2237 <dd>Standard integers (such as '4') are constants of
2238 the <a href="#t_integer">integer</a> type. Negative numbers may be used
2239 with integer types.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2240
2241 <dt><b>Floating point constants</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2242 <dd>Floating point constants use standard decimal notation (e.g. 123.421),
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2243 exponential notation (e.g. 1.23421e+2), or a more precise hexadecimal
2244 notation (see below). The assembler requires the exact decimal value of a
2245 floating-point constant. For example, the assembler accepts 1.25 but
2246 rejects 1.3 because 1.3 is a repeating decimal in binary. Floating point
2247 constants must have a <a href="#t_floating">floating point</a> type. </dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2248
2249 <dt><b>Null pointer constants</b></dt>
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]2250 <dd>The identifier '<tt>null</tt>' is recognized as a null pointer constant
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2251 and must be of <a href="#t_pointer">pointer type</a>.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2252</dl>
2253
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2254<p>The one non-intuitive notation for constants is the hexadecimal form of
2255 floating point constants. For example, the form '<tt>double
2256 0x432ff973cafa8000</tt>' is equivalent to (but harder to read than)
2257 '<tt>double 4.5e+15</tt>'. The only time hexadecimal floating point
2258 constants are required (and the only time that they are generated by the
2259 disassembler) is when a floating point constant must be emitted but it cannot
2260 be represented as a decimal floating point number in a reasonable number of
2261 digits. For example, NaN's, infinities, and other special values are
2262 represented in their IEEE hexadecimal format so that assembly and disassembly
2263 do not cause any bits to change in the constants.</p>
2264
Dale Johannesenbd5e5a82009-02-11 22:14:51 +0000[diff] [blame]2265<p>When using the hexadecimal form, constants of types float and double are
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2266 represented using the 16-digit form shown above (which matches the IEEE754
2267 representation for double); float values must, however, be exactly
2268 representable as IEE754 single precision. Hexadecimal format is always used
2269 for long double, and there are three forms of long double. The 80-bit format
2270 used by x86 is represented as <tt>0xK</tt> followed by 20 hexadecimal digits.
2271 The 128-bit format used by PowerPC (two adjacent doubles) is represented
2272 by <tt>0xM</tt> followed by 32 hexadecimal digits. The IEEE 128-bit format
2273 is represented by <tt>0xL</tt> followed by 32 hexadecimal digits; no
2274 currently supported target uses this format. Long doubles will only work if
2275 they match the long double format on your target. All hexadecimal formats
2276 are big-endian (sign bit at the left).</p>
2277
Dale Johannesen21fe99b2010-10-01 00:48:59 +0000[diff] [blame]2278<p>There are no constants of type x86mmx.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2279</div>
2280
2281<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2282<h3>
Bill Wendlingd9fe2982009-07-20 02:32:41 +0000[diff] [blame]2283<a name="aggregateconstants"></a> <!-- old anchor -->
2284<a name="complexconstants">Complex Constants</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2285</h3>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2286
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2287<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2288
Chris Lattner70882792009-02-28 18:32:25 +0000[diff] [blame]2289<p>Complex constants are a (potentially recursive) combination of simple
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2290 constants and smaller complex constants.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2291
2292<dl>
2293 <dt><b>Structure constants</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2294 <dd>Structure constants are represented with notation similar to structure
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2295 type definitions (a comma separated list of elements, surrounded by braces
2296 (<tt>{}</tt>)). For example: "<tt>{ i32 4, float 17.0, i32* @G }</tt>",
2297 where "<tt>@G</tt>" is declared as "<tt>@G = external global i32</tt>".
2298 Structure constants must have <a href="#t_struct">structure type</a>, and
2299 the number and types of elements must match those specified by the
2300 type.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2301
2302 <dt><b>Array constants</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2303 <dd>Array constants are represented with notation similar to array type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2304 definitions (a comma separated list of elements, surrounded by square
2305 brackets (<tt>[]</tt>)). For example: "<tt>[ i32 42, i32 11, i32 74
2306 ]</tt>". Array constants must have <a href="#t_array">array type</a>, and
2307 the number and types of elements must match those specified by the
2308 type.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2309
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2310 <dt><b>Vector constants</b></dt>
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2311 <dd>Vector constants are represented with notation similar to vector type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2312 definitions (a comma separated list of elements, surrounded by
2313 less-than/greater-than's (<tt>&lt;&gt;</tt>)). For example: "<tt>&lt; i32
2314 42, i32 11, i32 74, i32 100 &gt;</tt>". Vector constants must
2315 have <a href="#t_vector">vector type</a>, and the number and types of
2316 elements must match those specified by the type.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2317
2318 <dt><b>Zero initialization</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2319 <dd>The string '<tt>zeroinitializer</tt>' can be used to zero initialize a
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]2320 value to zero of <em>any</em> type, including scalar and
2321 <a href="#t_aggregate">aggregate</a> types.
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2322 This is often used to avoid having to print large zero initializers
2323 (e.g. for large arrays) and is always exactly equivalent to using explicit
2324 zero initializers.</dd>
Nick Lewycky21cc4462009-04-04 07:22:01 +0000[diff] [blame]2325
2326 <dt><b>Metadata node</b></dt>
Nick Lewycky1e8c7a62009-05-30 16:08:30 +0000[diff] [blame]2327 <dd>A metadata node is a structure-like constant with
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2328 <a href="#t_metadata">metadata type</a>. For example: "<tt>metadata !{
2329 i32 0, metadata !"test" }</tt>". Unlike other constants that are meant to
2330 be interpreted as part of the instruction stream, metadata is a place to
2331 attach additional information such as debug info.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2332</dl>
2333
2334</div>
2335
2336<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2337<h3>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2338 <a name="globalconstants">Global Variable and Function Addresses</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2339</h3>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2340
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2341<div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2342
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2343<p>The addresses of <a href="#globalvars">global variables</a>
2344 and <a href="#functionstructure">functions</a> are always implicitly valid
2345 (link-time) constants. These constants are explicitly referenced when
2346 the <a href="#identifiers">identifier for the global</a> is used and always
2347 have <a href="#t_pointer">pointer</a> type. For example, the following is a
2348 legal LLVM file:</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2349
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2350<pre class="doc_code">
Chris Lattnera18a4242007-06-06 18:28:13 +0000[diff] [blame]2351@X = global i32 17
2352@Y = global i32 42
2353@Z = global [2 x i32*] [ i32* @X, i32* @Y ]
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2354</pre>
2355
2356</div>
2357
2358<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2359<h3>
2360 <a name="undefvalues">Undefined Values</a>
2361</h3>
2362
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2363<div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2364
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2365<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]2366 indicates that the user of the value may receive an unspecified bit-pattern.
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]2367 Undefined values may be of any type (other than '<tt>label</tt>'
2368 or '<tt>void</tt>') and be used anywhere a constant is permitted.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2369
Chris Lattnerc608cb12009-09-11 01:49:31 +0000[diff] [blame]2370<p>Undefined values are useful because they indicate to the compiler that the
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2371 program is well defined no matter what value is used. This gives the
2372 compiler more freedom to optimize. Here are some examples of (potentially
2373 surprising) transformations that are valid (in pseudo IR):</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2374
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2375
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2376<pre class="doc_code">
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2377 %A = add %X, undef
2378 %B = sub %X, undef
2379 %C = xor %X, undef
2380Safe:
2381 %A = undef
2382 %B = undef
2383 %C = undef
2384</pre>
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2385
2386<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]2387 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]2388
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2389<pre class="doc_code">
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2390 %A = or %X, undef
2391 %B = and %X, undef
2392Safe:
2393 %A = -1
2394 %B = 0
2395Unsafe:
2396 %A = undef
2397 %B = undef
2398</pre>
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2399
2400<p>These logical operations have bits that are not always affected by the input.
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]2401 For example, if <tt>%X</tt> has a zero bit, then the output of the
2402 '<tt>and</tt>' operation will always be a zero for that bit, no matter what
2403 the corresponding bit from the '<tt>undef</tt>' is. As such, it is unsafe to
2404 optimize or assume that the result of the '<tt>and</tt>' is '<tt>undef</tt>'.
2405 However, it is safe to assume that all bits of the '<tt>undef</tt>' could be
2406 0, and optimize the '<tt>and</tt>' to 0. Likewise, it is safe to assume that
2407 all the bits of the '<tt>undef</tt>' operand to the '<tt>or</tt>' could be
2408 set, allowing the '<tt>or</tt>' to be folded to -1.</p>
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2409
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2410<pre class="doc_code">
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2411 %A = select undef, %X, %Y
2412 %B = select undef, 42, %Y
2413 %C = select %X, %Y, undef
2414Safe:
2415 %A = %X (or %Y)
2416 %B = 42 (or %Y)
2417 %C = %Y
2418Unsafe:
2419 %A = undef
2420 %B = undef
2421 %C = undef
2422</pre>
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2423
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]2424<p>This set of examples shows that undefined '<tt>select</tt>' (and conditional
2425 branch) conditions can go <em>either way</em>, but they have to come from one
2426 of the two operands. In the <tt>%A</tt> example, if <tt>%X</tt> and
2427 <tt>%Y</tt> were both known to have a clear low bit, then <tt>%A</tt> would
2428 have to have a cleared low bit. However, in the <tt>%C</tt> example, the
2429 optimizer is allowed to assume that the '<tt>undef</tt>' operand could be the
2430 same as <tt>%Y</tt>, allowing the whole '<tt>select</tt>' to be
2431 eliminated.</p>
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2432
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2433<pre class="doc_code">
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2434 %A = xor undef, undef
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]2435
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2436 %B = undef
2437 %C = xor %B, %B
2438
2439 %D = undef
2440 %E = icmp lt %D, 4
2441 %F = icmp gte %D, 4
2442
2443Safe:
2444 %A = undef
2445 %B = undef
2446 %C = undef
2447 %D = undef
2448 %E = undef
2449 %F = undef
2450</pre>
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2451
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]2452<p>This example points out that two '<tt>undef</tt>' operands are not
2453 necessarily the same. This can be surprising to people (and also matches C
2454 semantics) where they assume that "<tt>X^X</tt>" is always zero, even
2455 if <tt>X</tt> is undefined. This isn't true for a number of reasons, but the
2456 short answer is that an '<tt>undef</tt>' "variable" can arbitrarily change
2457 its value over its "live range". This is true because the variable doesn't
2458 actually <em>have a live range</em>. Instead, the value is logically read
2459 from arbitrary registers that happen to be around when needed, so the value
2460 is not necessarily consistent over time. In fact, <tt>%A</tt> and <tt>%C</tt>
2461 need to have the same semantics or the core LLVM "replace all uses with"
2462 concept would not hold.</p>
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2463
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2464<pre class="doc_code">
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2465 %A = fdiv undef, %X
2466 %B = fdiv %X, undef
2467Safe:
2468 %A = undef
2469b: unreachable
2470</pre>
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2471
2472<p>These examples show the crucial difference between an <em>undefined
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]2473 value</em> and <em>undefined behavior</em>. An undefined value (like
2474 '<tt>undef</tt>') is allowed to have an arbitrary bit-pattern. This means that
2475 the <tt>%A</tt> operation can be constant folded to '<tt>undef</tt>', because
2476 the '<tt>undef</tt>' could be an SNaN, and <tt>fdiv</tt> is not (currently)
2477 defined on SNaN's. However, in the second example, we can make a more
2478 aggressive assumption: because the <tt>undef</tt> is allowed to be an
2479 arbitrary value, we are allowed to assume that it could be zero. Since a
2480 divide by zero has <em>undefined behavior</em>, we are allowed to assume that
2481 the operation does not execute at all. This allows us to delete the divide and
2482 all code after it. Because the undefined operation "can't happen", the
2483 optimizer can assume that it occurs in dead code.</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]2484
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2485<pre class="doc_code">
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2486a: store undef -> %X
2487b: store %X -> undef
2488Safe:
2489a: &lt;deleted&gt;
2490b: unreachable
2491</pre>
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2492
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]2493<p>These examples reiterate the <tt>fdiv</tt> example: a store <em>of</em> an
2494 undefined value can be assumed to not have any effect; we can assume that the
2495 value is overwritten with bits that happen to match what was already there.
2496 However, a store <em>to</em> an undefined location could clobber arbitrary
2497 memory, therefore, it has undefined behavior.</p>
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2498
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2499</div>
2500
2501<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2502<h3>
2503 <a name="trapvalues">Trap Values</a>
2504</h3>
2505
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2506<div>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]2507
Dan Gohmanc68ce062010-04-26 20:21:21 +0000[diff] [blame]2508<p>Trap values are similar to <a href="#undefvalues">undef values</a>, however
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]2509 instead of representing an unspecified bit pattern, they represent the
2510 fact that an instruction or constant expression which cannot evoke side
2511 effects has nevertheless detected a condition which results in undefined
Dan Gohmanc68ce062010-04-26 20:21:21 +0000[diff] [blame]2512 behavior.</p>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]2513
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2514<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]2515 only exist when produced by operations such as
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2516 <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]2517
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2518<p>Trap value behavior is defined in terms of value <i>dependence</i>:</p>
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2519
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2520<ul>
2521<li>Values other than <a href="#i_phi"><tt>phi</tt></a> nodes depend on
2522 their operands.</li>
2523
2524<li><a href="#i_phi"><tt>Phi</tt></a> nodes depend on the operand corresponding
2525 to their dynamic predecessor basic block.</li>
2526
2527<li>Function arguments depend on the corresponding actual argument values in
2528 the dynamic callers of their functions.</li>
2529
2530<li><a href="#i_call"><tt>Call</tt></a> instructions depend on the
2531 <a href="#i_ret"><tt>ret</tt></a> instructions that dynamically transfer
2532 control back to them.</li>
2533
Dan Gohmanb5328162010-05-03 14:55:22 +0000[diff] [blame]2534<li><a href="#i_invoke"><tt>Invoke</tt></a> instructions depend on the
2535 <a href="#i_ret"><tt>ret</tt></a>, <a href="#i_unwind"><tt>unwind</tt></a>,
2536 or exception-throwing call instructions that dynamically transfer control
2537 back to them.</li>
2538
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2539<li>Non-volatile loads and stores depend on the most recent stores to all of the
2540 referenced memory addresses, following the order in the IR
2541 (including loads and stores implied by intrinsics such as
2542 <a href="#int_memcpy"><tt>@llvm.memcpy</tt></a>.)</li>
2543
Dan Gohman7c24ff12010-05-03 14:59:34 +0000[diff] [blame]2544<!-- TODO: In the case of multiple threads, this only applies if the store
2545 "happens-before" the load or store. -->
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2546
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2547<!-- TODO: floating-point exception state -->
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2548
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2549<li>An instruction with externally visible side effects depends on the most
2550 recent preceding instruction with externally visible side effects, following
Dan Gohmanff70fe42010-07-06 15:26:33 +0000[diff] [blame]2551 the order in the IR. (This includes
2552 <a href="#volatile">volatile operations</a>.)</li>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]2553
Dan Gohmanb5328162010-05-03 14:55:22 +0000[diff] [blame]2554<li>An instruction <i>control-depends</i> on a
2555 <a href="#terminators">terminator instruction</a>
2556 if the terminator instruction has multiple successors and the instruction
2557 is always executed when control transfers to one of the successors, and
Chris Lattner7a2bdde2011-04-15 05:18:47 +0000[diff] [blame]2558 may not be executed when control is transferred to another.</li>
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2559
Dan Gohmanca4cac42011-04-12 23:05:59 +0000[diff] [blame]2560<li>Additionally, an instruction also <i>control-depends</i> on a terminator
2561 instruction if the set of instructions it otherwise depends on would be
Chris Lattner7a2bdde2011-04-15 05:18:47 +0000[diff] [blame]2562 different if the terminator had transferred control to a different
Dan Gohmanca4cac42011-04-12 23:05:59 +0000[diff] [blame]2563 successor.</li>
2564
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2565<li>Dependence is transitive.</li>
2566
2567</ul>
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2568
2569<p>Whenever a trap value is generated, all values which depend on it evaluate
Lang Hames87d5cb82011-10-13 23:04:49 +0000[diff] [blame]2570 to trap. If they have side effects, they evoke their side effects as if each
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2571 operand with a trap value were undef. If they have externally-visible side
2572 effects, the behavior is undefined.</p>
2573
2574<p>Here are some examples:</p>
Dan Gohmanc30f6e12010-04-26 20:54:53 +0000[diff] [blame]2575
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2576<pre class="doc_code">
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2577entry:
2578 %trap = sub nuw i32 0, 1 ; Results in a trap value.
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2579 %still_trap = and i32 %trap, 0 ; Whereas (and i32 undef, 0) would return 0.
2580 %trap_yet_again = getelementptr i32* @h, i32 %still_trap
2581 store i32 0, i32* %trap_yet_again ; undefined behavior
2582
2583 store i32 %trap, i32* @g ; Trap value conceptually stored to memory.
2584 %trap2 = load i32* @g ; Returns a trap value, not just undef.
2585
2586 volatile store i32 %trap, i32* @g ; External observation; undefined behavior.
2587
2588 %narrowaddr = bitcast i32* @g to i16*
2589 %wideaddr = bitcast i32* @g to i64*
Nick Lewycky64f9fb12011-05-16 19:29:30 +0000[diff] [blame]2590 %trap3 = load i16* %narrowaddr ; Returns a trap value.
2591 %trap4 = load i64* %wideaddr ; Returns a trap value.
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2592
Nick Lewycky64f9fb12011-05-16 19:29:30 +0000[diff] [blame]2593 %cmp = icmp slt i32 %trap, 0 ; Returns a trap value.
2594 br i1 %cmp, label %true, label %end ; Branch to either destination.
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2595
2596true:
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2597 volatile store i32 0, i32* @g ; This is control-dependent on %cmp, so
2598 ; it has undefined behavior.
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2599 br label %end
2600
2601end:
2602 %p = phi i32 [ 0, %entry ], [ 1, %true ]
2603 ; Both edges into this PHI are
2604 ; control-dependent on %cmp, so this
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2605 ; always results in a trap value.
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2606
Dan Gohmanca4cac42011-04-12 23:05:59 +0000[diff] [blame]2607 volatile store i32 0, i32* @g ; This would depend on the store in %true
2608 ; if %cmp is true, or the store in %entry
2609 ; otherwise, so this is undefined behavior.
2610
Nick Lewycky64f9fb12011-05-16 19:29:30 +0000[diff] [blame]2611 br i1 %cmp, label %second_true, label %second_end
Dan Gohmanca4cac42011-04-12 23:05:59 +0000[diff] [blame]2612 ; The same branch again, but this time the
2613 ; true block doesn't have side effects.
2614
2615second_true:
2616 ; No side effects!
Nick Lewycky64f9fb12011-05-16 19:29:30 +0000[diff] [blame]2617 ret void
Dan Gohmanca4cac42011-04-12 23:05:59 +0000[diff] [blame]2618
2619second_end:
2620 volatile store i32 0, i32* @g ; This time, the instruction always depends
2621 ; on the store in %end. Also, it is
2622 ; control-equivalent to %end, so this is
Nick Lewycky64f9fb12011-05-16 19:29:30 +0000[diff] [blame]2623 ; well-defined (again, ignoring earlier
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2624 ; undefined behavior in this example).
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2625</pre>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]2626
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]2627</div>
2628
2629<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2630<h3>
2631 <a name="blockaddress">Addresses of Basic Blocks</a>
2632</h3>
2633
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2634<div>
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]2635
Chris Lattnercdfc9402009-11-01 01:27:45 +0000[diff] [blame]2636<p><b><tt>blockaddress(@function, %block)</tt></b></p>
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]2637
2638<p>The '<tt>blockaddress</tt>' constant computes the address of the specified
Chris Lattner2dfdf2a2009-10-27 21:49:40 +0000[diff] [blame]2639 basic block in the specified function, and always has an i8* type. Taking
Chris Lattnercdfc9402009-11-01 01:27:45 +0000[diff] [blame]2640 the address of the entry block is illegal.</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]2641
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]2642<p>This value only has defined behavior when used as an operand to the
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]2643 '<a href="#i_indirectbr"><tt>indirectbr</tt></a>' instruction, or for
2644 comparisons against null. Pointer equality tests between labels addresses
2645 results in undefined behavior &mdash; though, again, comparison against null
2646 is ok, and no label is equal to the null pointer. This may be passed around
2647 as an opaque pointer sized value as long as the bits are not inspected. This
2648 allows <tt>ptrtoint</tt> and arithmetic to be performed on these values so
2649 long as the original value is reconstituted before the <tt>indirectbr</tt>
2650 instruction.</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]2651
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]2652<p>Finally, some targets may provide defined semantics when using the value as
2653 the operand to an inline assembly, but that is target specific.</p>
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]2654
2655</div>
2656
2657
2658<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2659<h3>
2660 <a name="constantexprs">Constant Expressions</a>
2661</h3>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2662
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2663<div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2664
2665<p>Constant expressions are used to allow expressions involving other constants
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2666 to be used as constants. Constant expressions may be of
2667 any <a href="#t_firstclass">first class</a> type and may involve any LLVM
2668 operation that does not have side effects (e.g. load and call are not
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]2669 supported). The following is the syntax for constant expressions:</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2670
2671<dl>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2672 <dt><b><tt>trunc (CST to TYPE)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2673 <dd>Truncate a constant to another type. The bit size of CST must be larger
2674 than the bit size of TYPE. Both types must be integers.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2675
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2676 <dt><b><tt>zext (CST to TYPE)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2677 <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]2678 smaller than the bit size of TYPE. Both types must be integers.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2679
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2680 <dt><b><tt>sext (CST to TYPE)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2681 <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]2682 smaller than the bit size of TYPE. Both types must be integers.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2683
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2684 <dt><b><tt>fptrunc (CST to TYPE)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2685 <dd>Truncate a floating point constant to another floating point type. The
2686 size of CST must be larger than the size of TYPE. Both types must be
2687 floating point.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2688
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2689 <dt><b><tt>fpext (CST to TYPE)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2690 <dd>Floating point extend a constant to another type. The size of CST must be
2691 smaller or equal to the size of TYPE. Both types must be floating
2692 point.</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>fptoui (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 unsigned 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>fptosi (CST to TYPE)</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2702 <dd>Convert a floating point constant to the corresponding signed integer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2703 constant. TYPE must be a scalar or vector integer type. CST must be of
2704 scalar or vector floating point type. Both CST and TYPE must be scalars,
2705 or vectors of the same number of elements. If the value won't fit in the
2706 integer 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>uitofp (CST to TYPE)</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2709 <dd>Convert an unsigned 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>sitofp (CST to TYPE)</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2716 <dd>Convert a signed integer constant to the corresponding floating point
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2717 constant. TYPE must be a scalar or vector floating point type. CST must be
2718 of scalar or vector integer type. Both CST and TYPE must be scalars, or
2719 vectors of the same number of elements. If the value won't fit in the
2720 floating point type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2721
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2722 <dt><b><tt>ptrtoint (CST to TYPE)</tt></b></dt>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]2723 <dd>Convert a pointer typed constant to the corresponding integer constant
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2724 <tt>TYPE</tt> must be an integer type. <tt>CST</tt> must be of pointer
2725 type. The <tt>CST</tt> value is zero extended, truncated, or unchanged to
2726 make it fit in <tt>TYPE</tt>.</dd>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]2727
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2728 <dt><b><tt>inttoptr (CST to TYPE)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2729 <dd>Convert a integer constant to a pointer constant. TYPE must be a pointer
2730 type. CST must be of integer type. The CST value is zero extended,
2731 truncated, or unchanged to make it fit in a pointer size. This one is
2732 <i>really</i> dangerous!</dd>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]2733
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2734 <dt><b><tt>bitcast (CST to TYPE)</tt></b></dt>
Chris Lattner03bbad62009-02-28 18:27:03 +0000[diff] [blame]2735 <dd>Convert a constant, CST, to another TYPE. The constraints of the operands
2736 are the same as those for the <a href="#i_bitcast">bitcast
2737 instruction</a>.</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>getelementptr (CSTPTR, IDX0, IDX1, ...)</tt></b></dt>
2740 <dt><b><tt>getelementptr inbounds (CSTPTR, IDX0, IDX1, ...)</tt></b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2741 <dd>Perform the <a href="#i_getelementptr">getelementptr operation</a> on
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2742 constants. As with the <a href="#i_getelementptr">getelementptr</a>
2743 instruction, the index list may have zero or more indexes, which are
2744 required to make sense for the type of "CSTPTR".</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2745
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2746 <dt><b><tt>select (COND, VAL1, VAL2)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2747 <dd>Perform the <a href="#i_select">select operation</a> on constants.</dd>
Reid Spencer01c42592006-12-04 19:23:19 +0000[diff] [blame]2748
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2749 <dt><b><tt>icmp COND (VAL1, VAL2)</tt></b></dt>
Reid Spencer01c42592006-12-04 19:23:19 +0000[diff] [blame]2750 <dd>Performs the <a href="#i_icmp">icmp operation</a> on constants.</dd>
2751
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2752 <dt><b><tt>fcmp COND (VAL1, VAL2)</tt></b></dt>
Reid Spencer01c42592006-12-04 19:23:19 +0000[diff] [blame]2753 <dd>Performs the <a href="#i_fcmp">fcmp operation</a> on constants.</dd>
Robert Bocchino9fbe1452006-01-10 19:31:34 +0000[diff] [blame]2754
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2755 <dt><b><tt>extractelement (VAL, IDX)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2756 <dd>Perform the <a href="#i_extractelement">extractelement operation</a> on
2757 constants.</dd>
Robert Bocchino9fbe1452006-01-10 19:31:34 +0000[diff] [blame]2758
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2759 <dt><b><tt>insertelement (VAL, ELT, IDX)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2760 <dd>Perform the <a href="#i_insertelement">insertelement operation</a> on
2761 constants.</dd>
Chris Lattnerc1989542006-04-08 00:13:41 +0000[diff] [blame]2762
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2763 <dt><b><tt>shufflevector (VEC1, VEC2, IDXMASK)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2764 <dd>Perform the <a href="#i_shufflevector">shufflevector operation</a> on
2765 constants.</dd>
Chris Lattnerc1989542006-04-08 00:13:41 +0000[diff] [blame]2766
Nick Lewycky9e130ce2010-05-29 06:44:15 +0000[diff] [blame]2767 <dt><b><tt>extractvalue (VAL, IDX0, IDX1, ...)</tt></b></dt>
2768 <dd>Perform the <a href="#i_extractvalue">extractvalue operation</a> on
2769 constants. The index list is interpreted in a similar manner as indices in
2770 a '<a href="#i_getelementptr">getelementptr</a>' operation. At least one
2771 index value must be specified.</dd>
2772
2773 <dt><b><tt>insertvalue (VAL, ELT, IDX0, IDX1, ...)</tt></b></dt>
2774 <dd>Perform the <a href="#i_insertvalue">insertvalue operation</a> on
2775 constants. The index list is interpreted in a similar manner as indices in
2776 a '<a href="#i_getelementptr">getelementptr</a>' operation. At least one
2777 index value must be specified.</dd>
2778
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2779 <dt><b><tt>OPCODE (LHS, RHS)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2780 <dd>Perform the specified operation of the LHS and RHS constants. OPCODE may
2781 be any of the <a href="#binaryops">binary</a>
2782 or <a href="#bitwiseops">bitwise binary</a> operations. The constraints
2783 on operands are the same as those for the corresponding instruction
2784 (e.g. no bitwise operations on floating point values are allowed).</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2785</dl>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2786
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2787</div>
Chris Lattner9ee5d222004-03-08 16:49:10 +0000[diff] [blame]2788
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2789</div>
2790
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2791<!-- *********************************************************************** -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2792<h2><a name="othervalues">Other Values</a></h2>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2793<!-- *********************************************************************** -->
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2794<div>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2795<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2796<h3>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2797<a name="inlineasm">Inline Assembler Expressions</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2798</h3>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2799
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2800<div>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2801
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2802<p>LLVM supports inline assembler expressions (as opposed
2803 to <a href="#moduleasm"> Module-Level Inline Assembly</a>) through the use of
2804 a special value. This value represents the inline assembler as a string
2805 (containing the instructions to emit), a list of operand constraints (stored
Dale Johannesen09fed252009-10-13 21:56:55 +0000[diff] [blame]2806 as a string), a flag that indicates whether or not the inline asm
Dale Johannesen8ba2d5b2009-10-21 23:28:00 +0000[diff] [blame]2807 expression has side effects, and a flag indicating whether the function
2808 containing the asm needs to align its stack conservatively. An example
2809 inline assembler expression is:</p>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2810
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2811<pre class="doc_code">
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2812i32 (i32) asm "bswap $0", "=r,r"
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2813</pre>
2814
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2815<p>Inline assembler expressions may <b>only</b> be used as the callee operand of
2816 a <a href="#i_call"><tt>call</tt> instruction</a>. Thus, typically we
2817 have:</p>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2818
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2819<pre class="doc_code">
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2820%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]2821</pre>
2822
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2823<p>Inline asms with side effects not visible in the constraint list must be
2824 marked as having side effects. This is done through the use of the
2825 '<tt>sideeffect</tt>' keyword, like so:</p>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2826
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2827<pre class="doc_code">
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2828call void asm sideeffect "eieio", ""()
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2829</pre>
2830
Dale Johannesen8ba2d5b2009-10-21 23:28:00 +0000[diff] [blame]2831<p>In some cases inline asms will contain code that will not work unless the
2832 stack is aligned in some way, such as calls or SSE instructions on x86,
2833 yet will not contain code that does that alignment within the asm.
2834 The compiler should make conservative assumptions about what the asm might
2835 contain and should generate its usual stack alignment code in the prologue
2836 if the '<tt>alignstack</tt>' keyword is present:</p>
Dale Johannesen09fed252009-10-13 21:56:55 +0000[diff] [blame]2837
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2838<pre class="doc_code">
Dale Johannesen8ba2d5b2009-10-21 23:28:00 +0000[diff] [blame]2839call void asm alignstack "eieio", ""()
Dale Johannesen09fed252009-10-13 21:56:55 +0000[diff] [blame]2840</pre>
Dale Johannesen09fed252009-10-13 21:56:55 +0000[diff] [blame]2841
2842<p>If both keywords appear the '<tt>sideeffect</tt>' keyword must come
2843 first.</p>
2844
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2845<p>TODO: The format of the asm and constraints string still need to be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2846 documented here. Constraints on what can be done (e.g. duplication, moving,
2847 etc need to be documented). This is probably best done by reference to
2848 another document that covers inline asm from a holistic perspective.</p>
Chris Lattnercf9a4152010-04-07 05:38:05 +0000[diff] [blame]2849
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2850<h4>
Chris Lattnercf9a4152010-04-07 05:38:05 +0000[diff] [blame]2851<a name="inlineasm_md">Inline Asm Metadata</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2852</h4>
Chris Lattnercf9a4152010-04-07 05:38:05 +0000[diff] [blame]2853
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2854<div>
Chris Lattnercf9a4152010-04-07 05:38:05 +0000[diff] [blame]2855
2856<p>The call instructions that wrap inline asm nodes may have a "!srcloc" MDNode
Chris Lattnerce1b9ad2010-11-17 08:20:42 +0000[diff] [blame]2857 attached to it that contains a list of constant integers. If present, the
2858 code generator will use the integer as the location cookie value when report
Chris Lattnercf9a4152010-04-07 05:38:05 +0000[diff] [blame]2859 errors through the LLVMContext error reporting mechanisms. This allows a
Dan Gohman1c70c002010-04-28 00:36:01 +0000[diff] [blame]2860 front-end to correlate backend errors that occur with inline asm back to the
Chris Lattnercf9a4152010-04-07 05:38:05 +0000[diff] [blame]2861 source code that produced it. For example:</p>
2862
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2863<pre class="doc_code">
Chris Lattnercf9a4152010-04-07 05:38:05 +0000[diff] [blame]2864call void asm sideeffect "something bad", ""()<b>, !srcloc !42</b>
2865...
2866!42 = !{ i32 1234567 }
2867</pre>
Chris Lattnercf9a4152010-04-07 05:38:05 +0000[diff] [blame]2868
2869<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]2870 IR. If the MDNode contains multiple constants, the code generator will use
2871 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]2872
2873</div>
2874
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2875</div>
2876
Chris Lattnere6a5ddd2010-01-15 21:50:19 +0000[diff] [blame]2877<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2878<h3>
2879 <a name="metadata">Metadata Nodes and Metadata Strings</a>
2880</h3>
Chris Lattnere6a5ddd2010-01-15 21:50:19 +0000[diff] [blame]2881
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2882<div>
Chris Lattnere6a5ddd2010-01-15 21:50:19 +0000[diff] [blame]2883
2884<p>LLVM IR allows metadata to be attached to instructions in the program that
2885 can convey extra information about the code to the optimizers and code
2886 generator. One example application of metadata is source-level debug
2887 information. There are two metadata primitives: strings and nodes. All
2888 metadata has the <tt>metadata</tt> type and is identified in syntax by a
2889 preceding exclamation point ('<tt>!</tt>').</p>
2890
2891<p>A metadata string is a string surrounded by double quotes. It can contain
2892 any character by escaping non-printable characters with "\xx" where "xx" is
2893 the two digit hex code. For example: "<tt>!"test\00"</tt>".</p>
2894
2895<p>Metadata nodes are represented with notation similar to structure constants
2896 (a comma separated list of elements, surrounded by braces and preceded by an
2897 exclamation point). For example: "<tt>!{ metadata !"test\00", i32
2898 10}</tt>". Metadata nodes can have any values as their operand.</p>
2899
2900<p>A <a href="#namedmetadatastructure">named metadata</a> is a collection of
2901 metadata nodes, which can be looked up in the module symbol table. For
2902 example: "<tt>!foo = metadata !{!4, !3}</tt>".
2903
Devang Patele1d50cd2010-03-04 23:44:48 +0000[diff] [blame]2904<p>Metadata can be used as function arguments. Here <tt>llvm.dbg.value</tt>
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2905 function is using two metadata arguments.</p>
Devang Patele1d50cd2010-03-04 23:44:48 +0000[diff] [blame]2906
Bill Wendling9ff5de92011-03-02 02:17:11 +0000[diff] [blame]2907<div class="doc_code">
2908<pre>
2909call void @llvm.dbg.value(metadata !24, i64 0, metadata !25)
2910</pre>
2911</div>
Devang Patele1d50cd2010-03-04 23:44:48 +0000[diff] [blame]2912
2913<p>Metadata can be attached with an instruction. Here metadata <tt>!21</tt> is
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2914 attached with <tt>add</tt> instruction using <tt>!dbg</tt> identifier.</p>
Devang Patele1d50cd2010-03-04 23:44:48 +0000[diff] [blame]2915
Bill Wendling9ff5de92011-03-02 02:17:11 +0000[diff] [blame]2916<div class="doc_code">
2917<pre>
2918%indvar.next = add i64 %indvar, 1, !dbg !21
2919</pre>
2920</div>
2921
Peter Collingbourne249d9532011-10-27 19:19:07 +0000[diff] [blame^]2922<p>More information about specific metadata nodes recognized by the optimizers
2923 and code generator is found below.</p>
2924
2925<h4>
2926 <a name="tbaa">'<tt>tbaa</tt>' Metadata</a>
2927</h4>
2928
2929<div>
2930
2931<p>In LLVM IR, memory does not have types, so LLVM's own type system is not
2932 suitable for doing TBAA. Instead, metadata is added to the IR to describe
2933 a type system of a higher level language. This can be used to implement
2934 typical C/C++ TBAA, but it can also be used to implement custom alias
2935 analysis behavior for other languages.</p>
2936
2937<p>The current metadata format is very simple. TBAA metadata nodes have up to
2938 three fields, e.g.:</p>
2939
2940<div class="doc_code">
2941<pre>
2942!0 = metadata !{ metadata !"an example type tree" }
2943!1 = metadata !{ metadata !"int", metadata !0 }
2944!2 = metadata !{ metadata !"float", metadata !0 }
2945!3 = metadata !{ metadata !"const float", metadata !2, i64 1 }
2946</pre>
2947</div>
2948
2949<p>The first field is an identity field. It can be any value, usually
2950 a metadata string, which uniquely identifies the type. The most important
2951 name in the tree is the name of the root node. Two trees with
2952 different root node names are entirely disjoint, even if they
2953 have leaves with common names.</p>
2954
2955<p>The second field identifies the type's parent node in the tree, or
2956 is null or omitted for a root node. A type is considered to alias
2957 all of its descendants and all of its ancestors in the tree. Also,
2958 a type is considered to alias all types in other trees, so that
2959 bitcode produced from multiple front-ends is handled conservatively.</p>
2960
2961<p>If the third field is present, it's an integer which if equal to 1
2962 indicates that the type is "constant" (meaning
2963 <tt>pointsToConstantMemory</tt> should return true; see
2964 <a href="AliasAnalysis.html#OtherItfs">other useful
2965 <tt>AliasAnalysis</tt> methods</a>).</p>
2966
2967</div>
2968
Chris Lattnere6a5ddd2010-01-15 21:50:19 +0000[diff] [blame]2969</div>
2970
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2971</div>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]2972
2973<!-- *********************************************************************** -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2974<h2>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]2975 <a name="intrinsic_globals">Intrinsic Global Variables</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2976</h2>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]2977<!-- *********************************************************************** -->
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2978<div>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]2979<p>LLVM has a number of "magic" global variables that contain data that affect
2980code generation or other IR semantics. These are documented here. All globals
Chris Lattner401e10c2009-07-20 06:14:25 +0000[diff] [blame]2981of this sort should have a section specified as "<tt>llvm.metadata</tt>". This
2982section and all globals that start with "<tt>llvm.</tt>" are reserved for use
2983by LLVM.</p>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]2984
2985<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2986<h3>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]2987<a name="intg_used">The '<tt>llvm.used</tt>' Global Variable</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2988</h3>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]2989
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2990<div>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]2991
2992<p>The <tt>@llvm.used</tt> global is an array with i8* element type which has <a
2993href="#linkage_appending">appending linkage</a>. This array contains a list of
2994pointers to global variables and functions which may optionally have a pointer
2995cast formed of bitcast or getelementptr. For example, a legal use of it is:</p>
2996
2997<pre>
2998 @X = global i8 4
2999 @Y = global i32 123
3000
3001 @llvm.used = appending global [2 x i8*] [
3002 i8* @X,
3003 i8* bitcast (i32* @Y to i8*)
3004 ], section "llvm.metadata"
3005</pre>
3006
3007<p>If a global variable appears in the <tt>@llvm.used</tt> list, then the
3008compiler, assembler, and linker are required to treat the symbol as if there is
3009a reference to the global that it cannot see. For example, if a variable has
3010internal linkage and no references other than that from the <tt>@llvm.used</tt>
3011list, it cannot be deleted. This is commonly used to represent references from
3012inline asms and other things the compiler cannot "see", and corresponds to
3013"attribute((used))" in GNU C.</p>
3014
3015<p>On some targets, the code generator must emit a directive to the assembler or
3016object file to prevent the assembler and linker from molesting the symbol.</p>
3017
3018</div>
3019
3020<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3021<h3>
3022 <a name="intg_compiler_used">
3023 The '<tt>llvm.compiler.used</tt>' Global Variable
3024 </a>
3025</h3>
Chris Lattner401e10c2009-07-20 06:14:25 +0000[diff] [blame]3026
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3027<div>
Chris Lattner401e10c2009-07-20 06:14:25 +0000[diff] [blame]3028
3029<p>The <tt>@llvm.compiler.used</tt> directive is the same as the
3030<tt>@llvm.used</tt> directive, except that it only prevents the compiler from
3031touching the symbol. On targets that support it, this allows an intelligent
3032linker to optimize references to the symbol without being impeded as it would be
3033by <tt>@llvm.used</tt>.</p>
3034
3035<p>This is a rare construct that should only be used in rare circumstances, and
3036should not be exposed to source languages.</p>
3037
3038</div>
3039
3040<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3041<h3>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3042<a name="intg_global_ctors">The '<tt>llvm.global_ctors</tt>' Global Variable</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3043</h3>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3044
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3045<div>
David Chisnalle31e9962010-04-30 19:23:49 +0000[diff] [blame]3046<pre>
3047%0 = type { i32, void ()* }
David Chisnall27195a52010-04-30 19:27:35 +0000[diff] [blame]3048@llvm.global_ctors = appending global [1 x %0] [%0 { i32 65535, void ()* @ctor }]
David Chisnalle31e9962010-04-30 19:23:49 +0000[diff] [blame]3049</pre>
3050<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.
3051</p>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3052
3053</div>
3054
3055<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3056<h3>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3057<a name="intg_global_dtors">The '<tt>llvm.global_dtors</tt>' Global Variable</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3058</h3>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3059
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3060<div>
David Chisnalle31e9962010-04-30 19:23:49 +0000[diff] [blame]3061<pre>
3062%0 = type { i32, void ()* }
David Chisnall27195a52010-04-30 19:27:35 +0000[diff] [blame]3063@llvm.global_dtors = appending global [1 x %0] [%0 { i32 65535, void ()* @dtor }]
David Chisnalle31e9962010-04-30 19:23:49 +0000[diff] [blame]3064</pre>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3065
David Chisnalle31e9962010-04-30 19:23:49 +0000[diff] [blame]3066<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.
3067</p>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3068
3069</div>
3070
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3071</div>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3072
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]3073<!-- *********************************************************************** -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3074<h2><a name="instref">Instruction Reference</a></h2>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3075<!-- *********************************************************************** -->
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]3076
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3077<div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]3078
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3079<p>The LLVM instruction set consists of several different classifications of
3080 instructions: <a href="#terminators">terminator
3081 instructions</a>, <a href="#binaryops">binary instructions</a>,
3082 <a href="#bitwiseops">bitwise binary instructions</a>,
3083 <a href="#memoryops">memory instructions</a>, and
3084 <a href="#otherops">other instructions</a>.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]3085
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3086<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3087<h3>
3088 <a name="terminators">Terminator Instructions</a>
3089</h3>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]3090
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3091<div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]3092
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3093<p>As mentioned <a href="#functionstructure">previously</a>, every basic block
3094 in a program ends with a "Terminator" instruction, which indicates which
3095 block should be executed after the current block is finished. These
3096 terminator instructions typically yield a '<tt>void</tt>' value: they produce
3097 control flow, not values (the one exception being the
3098 '<a href="#i_invoke"><tt>invoke</tt></a>' instruction).</p>
3099
Chris Lattner6445ecb2011-08-02 20:29:13 +0000[diff] [blame]3100<p>The terminator instructions are:
3101 '<a href="#i_ret"><tt>ret</tt></a>',
3102 '<a href="#i_br"><tt>br</tt></a>',
3103 '<a href="#i_switch"><tt>switch</tt></a>',
3104 '<a href="#i_indirectbr"><tt>indirectbr</tt></a>',
3105 '<a href="#i_invoke"><tt>invoke</tt></a>',
3106 '<a href="#i_unwind"><tt>unwind</tt></a>',
3107 '<a href="#i_resume"><tt>resume</tt></a>', and
3108 '<a href="#i_unreachable"><tt>unreachable</tt></a>'.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]3109
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3110<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3111<h4>
3112 <a name="i_ret">'<tt>ret</tt>' Instruction</a>
3113</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3114
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3115<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3116
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3117<h5>Syntax:</h5>
Dan Gohmanb1e6b962008-10-04 19:00:07 +0000[diff] [blame]3118<pre>
3119 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]3120 ret void <i>; Return from void function</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3121</pre>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]3122
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3123<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3124<p>The '<tt>ret</tt>' instruction is used to return control flow (and optionally
3125 a value) from a function back to the caller.</p>
3126
3127<p>There are two forms of the '<tt>ret</tt>' instruction: one that returns a
3128 value and then causes control flow, and one that just causes control flow to
3129 occur.</p>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]3130
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3131<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3132<p>The '<tt>ret</tt>' instruction optionally accepts a single argument, the
3133 return value. The type of the return value must be a
3134 '<a href="#t_firstclass">first class</a>' type.</p>
Dan Gohmanb1e6b962008-10-04 19:00:07 +0000[diff] [blame]3135
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3136<p>A function is not <a href="#wellformed">well formed</a> if it it has a
3137 non-void return type and contains a '<tt>ret</tt>' instruction with no return
3138 value or a return value with a type that does not match its type, or if it
3139 has a void return type and contains a '<tt>ret</tt>' instruction with a
3140 return value.</p>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]3141
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3142<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3143<p>When the '<tt>ret</tt>' instruction is executed, control flow returns back to
3144 the calling function's context. If the caller is a
3145 "<a href="#i_call"><tt>call</tt></a>" instruction, execution continues at the
3146 instruction after the call. If the caller was an
3147 "<a href="#i_invoke"><tt>invoke</tt></a>" instruction, execution continues at
3148 the beginning of the "normal" destination block. If the instruction returns
3149 a value, that value shall set the call or invoke instruction's return
3150 value.</p>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]3151
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3152<h5>Example:</h5>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]3153<pre>
3154 ret i32 5 <i>; Return an integer value of 5</i>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]3155 ret void <i>; Return from a void function</i>
Bill Wendling0a4bbbf2009-02-28 22:12:54 +0000[diff] [blame]3156 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]3157</pre>
Dan Gohmanf3e60bd2009-01-12 23:12:39 +0000[diff] [blame]3158
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3159</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3160<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3161<h4>
3162 <a name="i_br">'<tt>br</tt>' Instruction</a>
3163</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3164
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3165<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3166
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3167<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3168<pre>
Bill Wendlingb3aa4712011-07-26 10:41:15 +0000[diff] [blame]3169 br i1 &lt;cond&gt;, label &lt;iftrue&gt;, label &lt;iffalse&gt;
3170 br label &lt;dest&gt; <i>; Unconditional branch</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3171</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3172
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3173<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3174<p>The '<tt>br</tt>' instruction is used to cause control flow to transfer to a
3175 different basic block in the current function. There are two forms of this
3176 instruction, corresponding to a conditional branch and an unconditional
3177 branch.</p>
3178
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3179<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3180<p>The conditional branch form of the '<tt>br</tt>' instruction takes a single
3181 '<tt>i1</tt>' value and two '<tt>label</tt>' values. The unconditional form
3182 of the '<tt>br</tt>' instruction takes a single '<tt>label</tt>' value as a
3183 target.</p>
3184
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3185<h5>Semantics:</h5>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3186<p>Upon execution of a conditional '<tt>br</tt>' instruction, the '<tt>i1</tt>'
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3187 argument is evaluated. If the value is <tt>true</tt>, control flows to the
3188 '<tt>iftrue</tt>' <tt>label</tt> argument. If "cond" is <tt>false</tt>,
3189 control flows to the '<tt>iffalse</tt>' <tt>label</tt> argument.</p>
3190
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3191<h5>Example:</h5>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]3192<pre>
3193Test:
3194 %cond = <a href="#i_icmp">icmp</a> eq i32 %a, %b
3195 br i1 %cond, label %IfEqual, label %IfUnequal
3196IfEqual:
3197 <a href="#i_ret">ret</a> i32 1
3198IfUnequal:
3199 <a href="#i_ret">ret</a> i32 0
3200</pre>
3201
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3202</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3203
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3204<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3205<h4>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3206 <a name="i_switch">'<tt>switch</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3207</h4>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3208
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3209<div>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3210
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3211<h5>Syntax:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3212<pre>
3213 switch &lt;intty&gt; &lt;value&gt;, label &lt;defaultdest&gt; [ &lt;intty&gt; &lt;val&gt;, label &lt;dest&gt; ... ]
3214</pre>
3215
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3216<h5>Overview:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3217<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]3218 several different places. It is a generalization of the '<tt>br</tt>'
3219 instruction, allowing a branch to occur to one of many possible
3220 destinations.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3221
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3222<h5>Arguments:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3223<p>The '<tt>switch</tt>' instruction uses three parameters: an integer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3224 comparison value '<tt>value</tt>', a default '<tt>label</tt>' destination,
3225 and an array of pairs of comparison value constants and '<tt>label</tt>'s.
3226 The table is not allowed to contain duplicate constant entries.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3227
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3228<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3229<p>The <tt>switch</tt> instruction specifies a table of values and
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3230 destinations. When the '<tt>switch</tt>' instruction is executed, this table
3231 is searched for the given value. If the value is found, control flow is
Benjamin Kramer8040cd32009-10-12 14:46:08 +0000[diff] [blame]3232 transferred to the corresponding destination; otherwise, control flow is
3233 transferred to the default destination.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3234
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3235<h5>Implementation:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3236<p>Depending on properties of the target machine and the particular
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3237 <tt>switch</tt> instruction, this instruction may be code generated in
3238 different ways. For example, it could be generated as a series of chained
3239 conditional branches or with a lookup table.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3240
3241<h5>Example:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3242<pre>
3243 <i>; Emulate a conditional br instruction</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3244 %Val = <a href="#i_zext">zext</a> i1 %value to i32
Dan Gohman2a08c532009-01-04 23:44:43 +0000[diff] [blame]3245 switch i32 %Val, label %truedest [ i32 0, label %falsedest ]
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3246
3247 <i>; Emulate an unconditional br instruction</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3248 switch i32 0, label %dest [ ]
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3249
3250 <i>; Implement a jump table:</i>
Dan Gohman2a08c532009-01-04 23:44:43 +0000[diff] [blame]3251 switch i32 %val, label %otherwise [ i32 0, label %onzero
3252 i32 1, label %onone
3253 i32 2, label %ontwo ]
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3254</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3255
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3256</div>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3257
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]3258
3259<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3260<h4>
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]3261 <a name="i_indirectbr">'<tt>indirectbr</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3262</h4>
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]3263
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3264<div>
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]3265
3266<h5>Syntax:</h5>
3267<pre>
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]3268 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]3269</pre>
3270
3271<h5>Overview:</h5>
3272
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]3273<p>The '<tt>indirectbr</tt>' instruction implements an indirect branch to a label
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]3274 within the current function, whose address is specified by
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]3275 "<tt>address</tt>". Address must be derived from a <a
3276 href="#blockaddress">blockaddress</a> constant.</p>
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]3277
3278<h5>Arguments:</h5>
3279
3280<p>The '<tt>address</tt>' argument is the address of the label to jump to. The
3281 rest of the arguments indicate the full set of possible destinations that the
3282 address may point to. Blocks are allowed to occur multiple times in the
3283 destination list, though this isn't particularly useful.</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3284
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]3285<p>This destination list is required so that dataflow analysis has an accurate
3286 understanding of the CFG.</p>
3287
3288<h5>Semantics:</h5>
3289
3290<p>Control transfers to the block specified in the address argument. All
3291 possible destination blocks must be listed in the label list, otherwise this
3292 instruction has undefined behavior. This implies that jumps to labels
3293 defined in other functions have undefined behavior as well.</p>
3294
3295<h5>Implementation:</h5>
3296
3297<p>This is typically implemented with a jump through a register.</p>
3298
3299<h5>Example:</h5>
3300<pre>
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]3301 indirectbr i8* %Addr, [ label %bb1, label %bb2, label %bb3 ]
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]3302</pre>
3303
3304</div>
3305
3306
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3307<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3308<h4>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3309 <a name="i_invoke">'<tt>invoke</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3310</h4>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3311
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3312<div>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3313
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3314<h5>Syntax:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3315<pre>
Devang Patel307e8ab2008-10-07 17:48:33 +0000[diff] [blame]3316 &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]3317 to label &lt;normal label&gt; unwind label &lt;exception label&gt;
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3318</pre>
3319
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]3320<h5>Overview:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3321<p>The '<tt>invoke</tt>' instruction causes control to transfer to a specified
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3322 function, with the possibility of control flow transfer to either the
3323 '<tt>normal</tt>' label or the '<tt>exception</tt>' label. If the callee
3324 function returns with the "<tt><a href="#i_ret">ret</a></tt>" instruction,
3325 control flow will return to the "normal" label. If the callee (or any
3326 indirect callees) returns with the "<a href="#i_unwind"><tt>unwind</tt></a>"
3327 instruction, control is interrupted and continued at the dynamically nearest
3328 "exception" label.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3329
Bill Wendlingf78faf82011-08-02 21:52:38 +0000[diff] [blame]3330<p>The '<tt>exception</tt>' label is a
3331 <i><a href="ExceptionHandling.html#overview">landing pad</a></i> for the
3332 exception. As such, '<tt>exception</tt>' label is required to have the
3333 "<a href="#i_landingpad"><tt>landingpad</tt></a>" instruction, which contains
3334 the information about about the behavior of the program after unwinding
3335 happens, as its first non-PHI instruction. The restrictions on the
3336 "<tt>landingpad</tt>" instruction's tightly couples it to the
3337 "<tt>invoke</tt>" instruction, so that the important information contained
3338 within the "<tt>landingpad</tt>" instruction can't be lost through normal
3339 code motion.</p>
3340
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3341<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3342<p>This instruction requires several arguments:</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3343
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3344<ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3345 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
3346 convention</a> the call should use. If none is specified, the call
3347 defaults to using C calling conventions.</li>
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]3348
3349 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3350 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
3351 '<tt>inreg</tt>' attributes are valid here.</li>
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]3352
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3353 <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]3354 function value being invoked. In most cases, this is a direct function
3355 invocation, but indirect <tt>invoke</tt>s are just as possible, branching
3356 off an arbitrary pointer to function value.</li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3357
3358 <li>'<tt>function ptr val</tt>': An LLVM value containing a pointer to a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3359 function to be invoked. </li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3360
3361 <li>'<tt>function args</tt>': argument list whose types match the function
Chris Lattner0724fbd2010-03-02 06:36:51 +0000[diff] [blame]3362 signature argument types and parameter attributes. All arguments must be
3363 of <a href="#t_firstclass">first class</a> type. If the function
3364 signature indicates the function accepts a variable number of arguments,
3365 the extra arguments can be specified.</li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3366
3367 <li>'<tt>normal label</tt>': the label reached when the called function
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3368 executes a '<tt><a href="#i_ret">ret</a></tt>' instruction. </li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3369
3370 <li>'<tt>exception label</tt>': the label reached when a callee returns with
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3371 the <a href="#i_unwind"><tt>unwind</tt></a> instruction. </li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3372
Devang Patel307e8ab2008-10-07 17:48:33 +0000[diff] [blame]3373 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3374 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
3375 '<tt>readnone</tt>' attributes are valid here.</li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3376</ol>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3377
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3378<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3379<p>This instruction is designed to operate as a standard
3380 '<tt><a href="#i_call">call</a></tt>' instruction in most regards. The
3381 primary difference is that it establishes an association with a label, which
3382 is used by the runtime library to unwind the stack.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3383
3384<p>This instruction is used in languages with destructors to ensure that proper
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3385 cleanup is performed in the case of either a <tt>longjmp</tt> or a thrown
3386 exception. Additionally, this is important for implementation of
3387 '<tt>catch</tt>' clauses in high-level languages that support them.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3388
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3389<p>For the purposes of the SSA form, the definition of the value returned by the
3390 '<tt>invoke</tt>' instruction is deemed to occur on the edge from the current
3391 block to the "normal" label. If the callee unwinds then no return value is
3392 available.</p>
Dan Gohmanf96a4992009-05-22 21:47:08 +0000[diff] [blame]3393
Chris Lattnerdf7a6802010-01-15 18:08:37 +0000[diff] [blame]3394<p>Note that the code generator does not yet completely support unwind, and
3395that the invoke/unwind semantics are likely to change in future versions.</p>
3396
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3397<h5>Example:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3398<pre>
Nick Lewyckyd703f652008-03-16 07:18:12 +0000[diff] [blame]3399 %retval = invoke i32 @Test(i32 15) to label %Continue
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]3400 unwind label %TestCleanup <i>; {i32}:retval set</i>
Nick Lewyckyd703f652008-03-16 07:18:12 +0000[diff] [blame]3401 %retval = invoke <a href="#callingconv">coldcc</a> i32 %Testfnptr(i32 15) to label %Continue
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]3402 unwind label %TestCleanup <i>; {i32}:retval set</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3403</pre>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3404
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3405</div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3406
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]3407<!-- _______________________________________________________________________ -->
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3408
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3409<h4>
3410 <a name="i_unwind">'<tt>unwind</tt>' Instruction</a>
3411</h4>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3412
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3413<div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3414
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]3415<h5>Syntax:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3416<pre>
3417 unwind
3418</pre>
3419
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]3420<h5>Overview:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3421<p>The '<tt>unwind</tt>' instruction unwinds the stack, continuing control flow
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3422 at the first callee in the dynamic call stack which used
3423 an <a href="#i_invoke"><tt>invoke</tt></a> instruction to perform the call.
3424 This is primarily used to implement exception handling.</p>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3425
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]3426<h5>Semantics:</h5>
Chris Lattner72ed2002008-04-19 21:01:16 +0000[diff] [blame]3427<p>The '<tt>unwind</tt>' instruction causes execution of the current function to
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3428 immediately halt. The dynamic call stack is then searched for the
3429 first <a href="#i_invoke"><tt>invoke</tt></a> instruction on the call stack.
3430 Once found, execution continues at the "exceptional" destination block
3431 specified by the <tt>invoke</tt> instruction. If there is no <tt>invoke</tt>
3432 instruction in the dynamic call chain, undefined behavior results.</p>
3433
Chris Lattnerdf7a6802010-01-15 18:08:37 +0000[diff] [blame]3434<p>Note that the code generator does not yet completely support unwind, and
3435that the invoke/unwind semantics are likely to change in future versions.</p>
3436
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3437</div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3438
Bill Wendlingdccc03b2011-07-31 06:30:59 +0000[diff] [blame]3439 <!-- _______________________________________________________________________ -->
3440
3441<h4>
3442 <a name="i_resume">'<tt>resume</tt>' Instruction</a>
3443</h4>
3444
3445<div>
3446
3447<h5>Syntax:</h5>
3448<pre>
3449 resume &lt;type&gt; &lt;value&gt;
3450</pre>
3451
3452<h5>Overview:</h5>
3453<p>The '<tt>resume</tt>' instruction is a terminator instruction that has no
3454 successors.</p>
3455
3456<h5>Arguments:</h5>
Bill Wendlingf78faf82011-08-02 21:52:38 +0000[diff] [blame]3457<p>The '<tt>resume</tt>' instruction requires one argument, which must have the
Bill Wendlinge4ad50b2011-08-03 18:37:32 +0000[diff] [blame]3458 same type as the result of any '<tt>landingpad</tt>' instruction in the same
3459 function.</p>
Bill Wendlingdccc03b2011-07-31 06:30:59 +0000[diff] [blame]3460
3461<h5>Semantics:</h5>
3462<p>The '<tt>resume</tt>' instruction resumes propagation of an existing
3463 (in-flight) exception whose unwinding was interrupted with
Bill Wendlingf78faf82011-08-02 21:52:38 +0000[diff] [blame]3464 a <a href="#i_landingpad"><tt>landingpad</tt></a> instruction.</p>
Bill Wendlingdccc03b2011-07-31 06:30:59 +0000[diff] [blame]3465
3466<h5>Example:</h5>
3467<pre>
Bill Wendlingf78faf82011-08-02 21:52:38 +0000[diff] [blame]3468 resume { i8*, i32 } %exn
Bill Wendlingdccc03b2011-07-31 06:30:59 +0000[diff] [blame]3469</pre>
3470
3471</div>
3472
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3473<!-- _______________________________________________________________________ -->
3474
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3475<h4>
3476 <a name="i_unreachable">'<tt>unreachable</tt>' Instruction</a>
3477</h4>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3478
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3479<div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3480
3481<h5>Syntax:</h5>
3482<pre>
3483 unreachable
3484</pre>
3485
3486<h5>Overview:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3487<p>The '<tt>unreachable</tt>' instruction has no defined semantics. This
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3488 instruction is used to inform the optimizer that a particular portion of the
3489 code is not reachable. This can be used to indicate that the code after a
3490 no-return function cannot be reached, and other facts.</p>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3491
3492<h5>Semantics:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3493<p>The '<tt>unreachable</tt>' instruction has no defined semantics.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3494
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3495</div>
3496
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3497</div>
3498
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3499<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3500<h3>
3501 <a name="binaryops">Binary Operations</a>
3502</h3>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3503
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3504<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3505
3506<p>Binary operators are used to do most of the computation in a program. They
3507 require two operands of the same type, execute an operation on them, and
3508 produce a single value. The operands might represent multiple data, as is
3509 the case with the <a href="#t_vector">vector</a> data type. The result value
3510 has the same type as its operands.</p>
3511
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3512<p>There are several different binary operators:</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3513
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3514<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3515<h4>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3516 <a name="i_add">'<tt>add</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3517</h4>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3518
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3519<div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3520
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3521<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3522<pre>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3523 &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]3524 &lt;result&gt; = add nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3525 &lt;result&gt; = add nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3526 &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]3527</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3528
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3529<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3530<p>The '<tt>add</tt>' instruction returns the sum of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3531
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3532<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3533<p>The two arguments to the '<tt>add</tt>' instruction must
3534 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3535 integer values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3536
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3537<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3538<p>The value produced is the integer sum of the two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3539
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3540<p>If the sum has unsigned overflow, the result returned is the mathematical
3541 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]3542
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3543<p>Because LLVM integers use a two's complement representation, this instruction
3544 is appropriate for both signed and unsigned integers.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3545
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]3546<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3547 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3548 <tt>nsw</tt> keywords are present, the result value of the <tt>add</tt>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]3549 is a <a href="#trapvalues">trap value</a> if unsigned and/or signed overflow,
3550 respectively, occurs.</p>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3551
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3552<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3553<pre>
3554 &lt;result&gt; = add i32 4, %var <i>; yields {i32}:result = 4 + %var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3555</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3556
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3557</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3558
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3559<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3560<h4>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3561 <a name="i_fadd">'<tt>fadd</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3562</h4>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3563
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3564<div>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3565
3566<h5>Syntax:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3567<pre>
3568 &lt;result&gt; = fadd &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3569</pre>
3570
3571<h5>Overview:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3572<p>The '<tt>fadd</tt>' instruction returns the sum of its two operands.</p>
3573
3574<h5>Arguments:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3575<p>The two arguments to the '<tt>fadd</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3576 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3577 floating point values. Both arguments must have identical types.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3578
3579<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3580<p>The value produced is the floating point sum of the two operands.</p>
3581
3582<h5>Example:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3583<pre>
3584 &lt;result&gt; = fadd float 4.0, %var <i>; yields {float}:result = 4.0 + %var</i>
3585</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3586
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3587</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3588
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3589<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3590<h4>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3591 <a name="i_sub">'<tt>sub</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3592</h4>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3593
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3594<div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3595
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3596<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3597<pre>
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]3598 &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]3599 &lt;result&gt; = sub nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3600 &lt;result&gt; = sub nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3601 &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]3602</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3603
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3604<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3605<p>The '<tt>sub</tt>' instruction returns the difference of its two
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3606 operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3607
3608<p>Note that the '<tt>sub</tt>' instruction is used to represent the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3609 '<tt>neg</tt>' instruction present in most other intermediate
3610 representations.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3611
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3612<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3613<p>The two arguments to the '<tt>sub</tt>' instruction must
3614 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3615 integer values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3616
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3617<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3618<p>The value produced is the integer difference of the two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3619
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3620<p>If the difference has unsigned overflow, the result returned is the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3621 mathematical result modulo 2<sup>n</sup>, where n is the bit width of the
3622 result.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3623
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3624<p>Because LLVM integers use a two's complement representation, this instruction
3625 is appropriate for both signed and unsigned integers.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3626
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]3627<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3628 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3629 <tt>nsw</tt> keywords are present, the result value of the <tt>sub</tt>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]3630 is a <a href="#trapvalues">trap value</a> if unsigned and/or signed overflow,
3631 respectively, occurs.</p>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3632
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3633<h5>Example:</h5>
Bill Wendlingaac388b2007-05-29 09:42:13 +0000[diff] [blame]3634<pre>
3635 &lt;result&gt; = sub i32 4, %var <i>; yields {i32}:result = 4 - %var</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3636 &lt;result&gt; = sub i32 0, %val <i>; yields {i32}:result = -%var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3637</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3638
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3639</div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3640
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3641<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3642<h4>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3643 <a name="i_fsub">'<tt>fsub</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3644</h4>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3645
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3646<div>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3647
3648<h5>Syntax:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3649<pre>
3650 &lt;result&gt; = fsub &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3651</pre>
3652
3653<h5>Overview:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3654<p>The '<tt>fsub</tt>' instruction returns the difference of its two
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3655 operands.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3656
3657<p>Note that the '<tt>fsub</tt>' instruction is used to represent the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3658 '<tt>fneg</tt>' instruction present in most other intermediate
3659 representations.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3660
3661<h5>Arguments:</h5>
Bill Wendlingd9fe2982009-07-20 02:32:41 +0000[diff] [blame]3662<p>The two arguments to the '<tt>fsub</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3663 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3664 floating point values. Both arguments must have identical types.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3665
3666<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3667<p>The value produced is the floating point difference of the two operands.</p>
3668
3669<h5>Example:</h5>
3670<pre>
3671 &lt;result&gt; = fsub float 4.0, %var <i>; yields {float}:result = 4.0 - %var</i>
3672 &lt;result&gt; = fsub float -0.0, %val <i>; yields {float}:result = -%var</i>
3673</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3674
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3675</div>
3676
3677<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3678<h4>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3679 <a name="i_mul">'<tt>mul</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3680</h4>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3681
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3682<div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3683
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3684<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3685<pre>
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]3686 &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]3687 &lt;result&gt; = mul nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3688 &lt;result&gt; = mul nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3689 &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]3690</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3691
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3692<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3693<p>The '<tt>mul</tt>' instruction returns the product of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3694
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3695<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3696<p>The two arguments to the '<tt>mul</tt>' instruction must
3697 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3698 integer values. Both arguments must have identical types.</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3699
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3700<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3701<p>The value produced is the integer product of the two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3702
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3703<p>If the result of the multiplication has unsigned overflow, the result
3704 returned is the mathematical result modulo 2<sup>n</sup>, where n is the bit
3705 width of the result.</p>
3706
3707<p>Because LLVM integers use a two's complement representation, and the result
3708 is the same width as the operands, this instruction returns the correct
3709 result for both signed and unsigned integers. If a full product
3710 (e.g. <tt>i32</tt>x<tt>i32</tt>-><tt>i64</tt>) is needed, the operands should
3711 be sign-extended or zero-extended as appropriate to the width of the full
3712 product.</p>
3713
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]3714<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3715 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3716 <tt>nsw</tt> keywords are present, the result value of the <tt>mul</tt>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]3717 is a <a href="#trapvalues">trap value</a> if unsigned and/or signed overflow,
3718 respectively, occurs.</p>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3719
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3720<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3721<pre>
3722 &lt;result&gt; = mul i32 4, %var <i>; yields {i32}:result = 4 * %var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3723</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3724
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3725</div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3726
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3727<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3728<h4>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3729 <a name="i_fmul">'<tt>fmul</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3730</h4>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3731
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3732<div>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3733
3734<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3735<pre>
3736 &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]3737</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3738
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3739<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3740<p>The '<tt>fmul</tt>' instruction returns the product of its two operands.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3741
3742<h5>Arguments:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3743<p>The two arguments to the '<tt>fmul</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3744 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3745 floating point values. Both arguments must have identical types.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3746
3747<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3748<p>The value produced is the floating point product of the two operands.</p>
3749
3750<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3751<pre>
3752 &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]3753</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3754
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3755</div>
3756
3757<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3758<h4>
3759 <a name="i_udiv">'<tt>udiv</tt>' Instruction</a>
3760</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3761
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3762<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3763
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3764<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3765<pre>
Chris Lattner35bda892011-02-06 21:44:57 +0000[diff] [blame]3766 &lt;result&gt; = udiv &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3767 &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]3768</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3769
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3770<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3771<p>The '<tt>udiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3772
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3773<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3774<p>The two arguments to the '<tt>udiv</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3775 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3776 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3777
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3778<h5>Semantics:</h5>
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3779<p>The value produced is the unsigned integer quotient of the two operands.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3780
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3781<p>Note that unsigned integer division and signed integer division are distinct
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3782 operations; for signed integer division, use '<tt>sdiv</tt>'.</p>
3783
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3784<p>Division by zero leads to undefined behavior.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3785
Chris Lattner35bda892011-02-06 21:44:57 +0000[diff] [blame]3786<p>If the <tt>exact</tt> keyword is present, the result value of the
3787 <tt>udiv</tt> is a <a href="#trapvalues">trap value</a> if %op1 is not a
3788 multiple of %op2 (as such, "((a udiv exact b) mul b) == a").</p>
3789
3790
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3791<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3792<pre>
3793 &lt;result&gt; = udiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3794</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3795
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3796</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3797
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3798<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3799<h4>
3800 <a name="i_sdiv">'<tt>sdiv</tt>' Instruction</a>
3801</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3802
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3803<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3804
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3805<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3806<pre>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3807 &lt;result&gt; = 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]3808 &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]3809</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3810
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3811<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3812<p>The '<tt>sdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3813
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3814<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3815<p>The two arguments to the '<tt>sdiv</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3816 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3817 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3818
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3819<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3820<p>The value produced is the signed integer quotient of the two operands rounded
3821 towards zero.</p>
3822
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3823<p>Note that signed integer division and unsigned integer division are distinct
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3824 operations; for unsigned integer division, use '<tt>udiv</tt>'.</p>
3825
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3826<p>Division by zero leads to undefined behavior. Overflow also leads to
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3827 undefined behavior; this is a rare case, but can occur, for example, by doing
3828 a 32-bit division of -2147483648 by -1.</p>
3829
Dan Gohman9c5beed2009-07-22 00:04:19 +0000[diff] [blame]3830<p>If the <tt>exact</tt> keyword is present, the result value of the
Dan Gohman27ef9972010-04-23 15:23:32 +0000[diff] [blame]3831 <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]3832 be rounded.</p>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3833
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3834<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3835<pre>
3836 &lt;result&gt; = sdiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3837</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3838
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3839</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3840
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3841<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3842<h4>
3843 <a name="i_fdiv">'<tt>fdiv</tt>' Instruction</a>
3844</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3845
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3846<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3847
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3848<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3849<pre>
Gabor Greiffb224a22008-08-07 21:46:00 +0000[diff] [blame]3850 &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]3851</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3852
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3853<h5>Overview:</h5>
3854<p>The '<tt>fdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3855
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3856<h5>Arguments:</h5>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]3857<p>The two arguments to the '<tt>fdiv</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3858 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3859 floating point values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3860
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3861<h5>Semantics:</h5>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3862<p>The value produced is the floating point quotient of the two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3863
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3864<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3865<pre>
3866 &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]3867</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3868
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3869</div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3870
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3871<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3872<h4>
3873 <a name="i_urem">'<tt>urem</tt>' Instruction</a>
3874</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3875
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3876<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3877
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3878<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3879<pre>
3880 &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]3881</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3882
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3883<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3884<p>The '<tt>urem</tt>' instruction returns the remainder from the unsigned
3885 division of its two arguments.</p>
3886
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3887<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3888<p>The two arguments to the '<tt>urem</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3889 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3890 values. Both arguments must have identical types.</p>
3891
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3892<h5>Semantics:</h5>
3893<p>This instruction returns the unsigned integer <i>remainder</i> of a division.
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3894 This instruction always performs an unsigned division to get the
3895 remainder.</p>
3896
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3897<p>Note that unsigned integer remainder and signed integer remainder are
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3898 distinct operations; for signed integer remainder, use '<tt>srem</tt>'.</p>
3899
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3900<p>Taking the remainder of a division by zero leads to undefined behavior.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3901
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3902<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3903<pre>
3904 &lt;result&gt; = urem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3905</pre>
3906
3907</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3908
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3909<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3910<h4>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3911 <a name="i_srem">'<tt>srem</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3912</h4>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3913
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3914<div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3915
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3916<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3917<pre>
Gabor Greiffb224a22008-08-07 21:46:00 +0000[diff] [blame]3918 &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]3919</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3920
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3921<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3922<p>The '<tt>srem</tt>' instruction returns the remainder from the signed
3923 division of its two operands. This instruction can also take
3924 <a href="#t_vector">vector</a> versions of the values in which case the
3925 elements must be integers.</p>
Chris Lattnerc7d3ab32008-01-04 04:33:49 +0000[diff] [blame]3926
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3927<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3928<p>The two arguments to the '<tt>srem</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3929 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3930 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3931
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3932<h5>Semantics:</h5>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3933<p>This instruction returns the <i>remainder</i> of a division (where the result
Duncan Sandsdea3a5e2011-03-07 09:12:24 +0000[diff] [blame]3934 is either zero or has the same sign as the dividend, <tt>op1</tt>), not the
3935 <i>modulo</i> operator (where the result is either zero or has the same sign
3936 as the divisor, <tt>op2</tt>) of a value.
3937 For more information about the difference,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3938 see <a href="http://mathforum.org/dr.math/problems/anne.4.28.99.html">The
3939 Math Forum</a>. For a table of how this is implemented in various languages,
3940 please see <a href="http://en.wikipedia.org/wiki/Modulo_operation">
3941 Wikipedia: modulo operation</a>.</p>
3942
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3943<p>Note that signed integer remainder and unsigned integer remainder are
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3944 distinct operations; for unsigned integer remainder, use '<tt>urem</tt>'.</p>
3945
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3946<p>Taking the remainder of a division by zero leads to undefined behavior.
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3947 Overflow also leads to undefined behavior; this is a rare case, but can
3948 occur, for example, by taking the remainder of a 32-bit division of
3949 -2147483648 by -1. (The remainder doesn't actually overflow, but this rule
3950 lets srem be implemented using instructions that return both the result of
3951 the division and the remainder.)</p>
3952
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3953<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3954<pre>
3955 &lt;result&gt; = srem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3956</pre>
3957
3958</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3959
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3960<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3961<h4>
3962 <a name="i_frem">'<tt>frem</tt>' Instruction</a>
3963</h4>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3964
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3965<div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3966
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3967<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3968<pre>
3969 &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]3970</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3971
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3972<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3973<p>The '<tt>frem</tt>' instruction returns the remainder from the division of
3974 its two operands.</p>
3975
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3976<h5>Arguments:</h5>
3977<p>The two arguments to the '<tt>frem</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3978 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3979 floating point values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3980
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3981<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3982<p>This instruction returns the <i>remainder</i> of a division. The remainder
3983 has the same sign as the dividend.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3984
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3985<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3986<pre>
3987 &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]3988</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3989
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3990</div>
Robert Bocchino7b81c752006-02-17 21:18:08 +0000[diff] [blame]3991
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3992</div>
3993
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]3994<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3995<h3>
3996 <a name="bitwiseops">Bitwise Binary Operations</a>
3997</h3>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3998
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3999<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4000
4001<p>Bitwise binary operators are used to do various forms of bit-twiddling in a
4002 program. They are generally very efficient instructions and can commonly be
4003 strength reduced from other instructions. They require two operands of the
4004 same type, execute an operation on them, and produce a single value. The
4005 resulting value is the same type as its operands.</p>
4006
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4007<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4008<h4>
4009 <a name="i_shl">'<tt>shl</tt>' Instruction</a>
4010</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4011
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4012<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4013
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4014<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4015<pre>
Chris Lattnerf067d582011-02-07 16:40:21 +0000[diff] [blame]4016 &lt;result&gt; = shl &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
4017 &lt;result&gt; = shl nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
4018 &lt;result&gt; = shl nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
4019 &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]4020</pre>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]4021
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4022<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4023<p>The '<tt>shl</tt>' instruction returns the first operand shifted to the left
4024 a specified number of bits.</p>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]4025
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4026<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4027<p>Both arguments to the '<tt>shl</tt>' instruction must be the
4028 same <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
4029 integer type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4030
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4031<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4032<p>The value produced is <tt>op1</tt> * 2<sup><tt>op2</tt></sup> mod
4033 2<sup>n</sup>, where <tt>n</tt> is the width of the result. If <tt>op2</tt>
4034 is (statically or dynamically) negative or equal to or larger than the number
4035 of bits in <tt>op1</tt>, the result is undefined. If the arguments are
4036 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
4037 shift amount in <tt>op2</tt>.</p>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]4038
Chris Lattnerf067d582011-02-07 16:40:21 +0000[diff] [blame]4039<p>If the <tt>nuw</tt> keyword is present, then the shift produces a
4040 <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]4041 the <tt>nsw</tt> keyword is present, then the shift produces a
Chris Lattnerf067d582011-02-07 16:40:21 +0000[diff] [blame]4042 <a href="#trapvalues">trap value</a> if it shifts out any bits that disagree
4043 with the resultant sign bit. As such, NUW/NSW have the same semantics as
4044 they would if the shift were expressed as a mul instruction with the same
4045 nsw/nuw bits in (mul %op1, (shl 1, %op2)).</p>
4046
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4047<h5>Example:</h5>
4048<pre>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4049 &lt;result&gt; = shl i32 4, %var <i>; yields {i32}: 4 &lt;&lt; %var</i>
4050 &lt;result&gt; = shl i32 4, 2 <i>; yields {i32}: 16</i>
4051 &lt;result&gt; = shl i32 1, 10 <i>; yields {i32}: 1024</i>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]4052 &lt;result&gt; = shl i32 1, 32 <i>; undefined</i>
Mon P Wange9f10152008-12-09 05:46:39 +0000[diff] [blame]4053 &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]4054</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4055
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4056</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4057
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4058<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4059<h4>
4060 <a name="i_lshr">'<tt>lshr</tt>' Instruction</a>
4061</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4062
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4063<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4064
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4065<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4066<pre>
Chris Lattnerf067d582011-02-07 16:40:21 +0000[diff] [blame]4067 &lt;result&gt; = lshr &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
4068 &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]4069</pre>
4070
4071<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4072<p>The '<tt>lshr</tt>' instruction (logical shift right) returns the first
4073 operand shifted to the right a specified number of bits with zero fill.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4074
4075<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4076<p>Both arguments to the '<tt>lshr</tt>' instruction must be the same
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4077 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
4078 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4079
4080<h5>Semantics:</h5>
4081<p>This instruction always performs a logical shift right operation. The most
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4082 significant bits of the result will be filled with zero bits after the shift.
4083 If <tt>op2</tt> is (statically or dynamically) equal to or larger than the
4084 number of bits in <tt>op1</tt>, the result is undefined. If the arguments are
4085 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
4086 shift amount in <tt>op2</tt>.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4087
Chris Lattnerf067d582011-02-07 16:40:21 +0000[diff] [blame]4088<p>If the <tt>exact</tt> keyword is present, the result value of the
4089 <tt>lshr</tt> is a <a href="#trapvalues">trap value</a> if any of the bits
4090 shifted out are non-zero.</p>
4091
4092
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4093<h5>Example:</h5>
4094<pre>
4095 &lt;result&gt; = lshr i32 4, 1 <i>; yields {i32}:result = 2</i>
4096 &lt;result&gt; = lshr i32 4, 2 <i>; yields {i32}:result = 1</i>
4097 &lt;result&gt; = lshr i8 4, 3 <i>; yields {i8}:result = 0</i>
4098 &lt;result&gt; = lshr i8 -2, 1 <i>; yields {i8}:result = 0x7FFFFFFF </i>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]4099 &lt;result&gt; = lshr i32 1, 32 <i>; undefined</i>
Mon P Wange9f10152008-12-09 05:46:39 +0000[diff] [blame]4100 &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]4101</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4102
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4103</div>
4104
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]4105<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4106<h4>
4107 <a name="i_ashr">'<tt>ashr</tt>' Instruction</a>
4108</h4>
4109
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4110<div>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4111
4112<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4113<pre>
Chris Lattnerf067d582011-02-07 16:40:21 +0000[diff] [blame]4114 &lt;result&gt; = ashr &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
4115 &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]4116</pre>
4117
4118<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4119<p>The '<tt>ashr</tt>' instruction (arithmetic shift right) returns the first
4120 operand shifted to the right a specified number of bits with sign
4121 extension.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4122
4123<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4124<p>Both arguments to the '<tt>ashr</tt>' instruction must be the same
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4125 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
4126 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4127
4128<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4129<p>This instruction always performs an arithmetic shift right operation, The
4130 most significant bits of the result will be filled with the sign bit
4131 of <tt>op1</tt>. If <tt>op2</tt> is (statically or dynamically) equal to or
4132 larger than the number of bits in <tt>op1</tt>, the result is undefined. If
4133 the arguments are vectors, each vector element of <tt>op1</tt> is shifted by
4134 the corresponding shift amount in <tt>op2</tt>.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4135
Chris Lattnerf067d582011-02-07 16:40:21 +0000[diff] [blame]4136<p>If the <tt>exact</tt> keyword is present, the result value of the
4137 <tt>ashr</tt> is a <a href="#trapvalues">trap value</a> if any of the bits
4138 shifted out are non-zero.</p>
4139
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4140<h5>Example:</h5>
4141<pre>
4142 &lt;result&gt; = ashr i32 4, 1 <i>; yields {i32}:result = 2</i>
4143 &lt;result&gt; = ashr i32 4, 2 <i>; yields {i32}:result = 1</i>
4144 &lt;result&gt; = ashr i8 4, 3 <i>; yields {i8}:result = 0</i>
4145 &lt;result&gt; = ashr i8 -2, 1 <i>; yields {i8}:result = -1</i>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]4146 &lt;result&gt; = ashr i32 1, 32 <i>; undefined</i>
Mon P Wange9f10152008-12-09 05:46:39 +0000[diff] [blame]4147 &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]4148</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4149
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4150</div>
4151
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4152<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4153<h4>
4154 <a name="i_and">'<tt>and</tt>' Instruction</a>
4155</h4>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4156
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4157<div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4158
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4159<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4160<pre>
Gabor Greiffb224a22008-08-07 21:46:00 +0000[diff] [blame]4161 &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]4162</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4163
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4164<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4165<p>The '<tt>and</tt>' instruction returns the bitwise logical and of its two
4166 operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4167
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4168<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4169<p>The two arguments to the '<tt>and</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4170 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
4171 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4172
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4173<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4174<p>The truth table used for the '<tt>and</tt>' instruction is:</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4175
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4176<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4177 <tbody>
4178 <tr>
4179 <td>In0</td>
4180 <td>In1</td>
4181 <td>Out</td>
4182 </tr>
4183 <tr>
4184 <td>0</td>
4185 <td>0</td>
4186 <td>0</td>
4187 </tr>
4188 <tr>
4189 <td>0</td>
4190 <td>1</td>
4191 <td>0</td>
4192 </tr>
4193 <tr>
4194 <td>1</td>
4195 <td>0</td>
4196 <td>0</td>
4197 </tr>
4198 <tr>
4199 <td>1</td>
4200 <td>1</td>
4201 <td>1</td>
4202 </tr>
4203 </tbody>
4204</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4205
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4206<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4207<pre>
4208 &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]4209 &lt;result&gt; = and i32 15, 40 <i>; yields {i32}:result = 8</i>
4210 &lt;result&gt; = and i32 4, 8 <i>; yields {i32}:result = 0</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4211</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4212</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4213<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4214<h4>
4215 <a name="i_or">'<tt>or</tt>' Instruction</a>
4216</h4>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4217
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4218<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4219
4220<h5>Syntax:</h5>
4221<pre>
4222 &lt;result&gt; = or &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
4223</pre>
4224
4225<h5>Overview:</h5>
4226<p>The '<tt>or</tt>' instruction returns the bitwise logical inclusive or of its
4227 two operands.</p>
4228
4229<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4230<p>The two arguments to the '<tt>or</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4231 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
4232 values. Both arguments must have identical types.</p>
4233
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4234<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4235<p>The truth table used for the '<tt>or</tt>' instruction is:</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4236
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4237<table border="1" cellspacing="0" cellpadding="4">
4238 <tbody>
4239 <tr>
4240 <td>In0</td>
4241 <td>In1</td>
4242 <td>Out</td>
4243 </tr>
4244 <tr>
4245 <td>0</td>
4246 <td>0</td>
4247 <td>0</td>
4248 </tr>
4249 <tr>
4250 <td>0</td>
4251 <td>1</td>
4252 <td>1</td>
4253 </tr>
4254 <tr>
4255 <td>1</td>
4256 <td>0</td>
4257 <td>1</td>
4258 </tr>
4259 <tr>
4260 <td>1</td>
4261 <td>1</td>
4262 <td>1</td>
4263 </tr>
4264 </tbody>
4265</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4266
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4267<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4268<pre>
4269 &lt;result&gt; = or i32 4, %var <i>; yields {i32}:result = 4 | %var</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4270 &lt;result&gt; = or i32 15, 40 <i>; yields {i32}:result = 47</i>
4271 &lt;result&gt; = or i32 4, 8 <i>; yields {i32}:result = 12</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4272</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4273
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4274</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4275
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4276<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4277<h4>
4278 <a name="i_xor">'<tt>xor</tt>' Instruction</a>
4279</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4280
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4281<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4282
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4283<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4284<pre>
4285 &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]4286</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4287
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4288<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4289<p>The '<tt>xor</tt>' instruction returns the bitwise logical exclusive or of
4290 its two operands. The <tt>xor</tt> is used to implement the "one's
4291 complement" operation, which is the "~" operator in C.</p>
4292
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4293<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4294<p>The two arguments to the '<tt>xor</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4295 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
4296 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4297
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4298<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4299<p>The truth table used for the '<tt>xor</tt>' instruction is:</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4300
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4301<table border="1" cellspacing="0" cellpadding="4">
4302 <tbody>
4303 <tr>
4304 <td>In0</td>
4305 <td>In1</td>
4306 <td>Out</td>
4307 </tr>
4308 <tr>
4309 <td>0</td>
4310 <td>0</td>
4311 <td>0</td>
4312 </tr>
4313 <tr>
4314 <td>0</td>
4315 <td>1</td>
4316 <td>1</td>
4317 </tr>
4318 <tr>
4319 <td>1</td>
4320 <td>0</td>
4321 <td>1</td>
4322 </tr>
4323 <tr>
4324 <td>1</td>
4325 <td>1</td>
4326 <td>0</td>
4327 </tr>
4328 </tbody>
4329</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4330
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4331<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4332<pre>
4333 &lt;result&gt; = xor i32 4, %var <i>; yields {i32}:result = 4 ^ %var</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4334 &lt;result&gt; = xor i32 15, 40 <i>; yields {i32}:result = 39</i>
4335 &lt;result&gt; = xor i32 4, 8 <i>; yields {i32}:result = 12</i>
4336 &lt;result&gt; = xor i32 %V, -1 <i>; yields {i32}:result = ~%V</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4337</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4338
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4339</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4340
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4341</div>
4342
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4343<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4344<h3>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4345 <a name="vectorops">Vector Operations</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4346</h3>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4347
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4348<div>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4349
4350<p>LLVM supports several instructions to represent vector operations in a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4351 target-independent manner. These instructions cover the element-access and
4352 vector-specific operations needed to process vectors effectively. While LLVM
4353 does directly support these vector operations, many sophisticated algorithms
4354 will want to use target-specific intrinsics to take full advantage of a
4355 specific target.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4356
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4357<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4358<h4>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4359 <a name="i_extractelement">'<tt>extractelement</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4360</h4>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4361
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4362<div>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4363
4364<h5>Syntax:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4365<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4366 &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]4367</pre>
4368
4369<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4370<p>The '<tt>extractelement</tt>' instruction extracts a single scalar element
4371 from a vector at a specified index.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4372
4373
4374<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4375<p>The first operand of an '<tt>extractelement</tt>' instruction is a value
4376 of <a href="#t_vector">vector</a> type. The second operand is an index
4377 indicating the position from which to extract the element. The index may be
4378 a variable.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4379
4380<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4381<p>The result is a scalar of the same type as the element type of
4382 <tt>val</tt>. Its value is the value at position <tt>idx</tt> of
4383 <tt>val</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
4384 results are undefined.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4385
4386<h5>Example:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4387<pre>
Gabor Greifa5b6f452009-10-28 13:14:50 +0000[diff] [blame]4388 &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]4389</pre>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4390
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4391</div>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4392
4393<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4394<h4>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4395 <a name="i_insertelement">'<tt>insertelement</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4396</h4>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4397
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4398<div>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4399
4400<h5>Syntax:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4401<pre>
Dan Gohmanf3480b92008-05-12 23:38:42 +0000[diff] [blame]4402 &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]4403</pre>
4404
4405<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4406<p>The '<tt>insertelement</tt>' instruction inserts a scalar element into a
4407 vector at a specified index.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4408
4409<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4410<p>The first operand of an '<tt>insertelement</tt>' instruction is a value
4411 of <a href="#t_vector">vector</a> type. The second operand is a scalar value
4412 whose type must equal the element type of the first operand. The third
4413 operand is an index indicating the position at which to insert the value.
4414 The index may be a variable.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4415
4416<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4417<p>The result is a vector of the same type as <tt>val</tt>. Its element values
4418 are those of <tt>val</tt> except at position <tt>idx</tt>, where it gets the
4419 value <tt>elt</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
4420 results are undefined.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4421
4422<h5>Example:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4423<pre>
Gabor Greifa5b6f452009-10-28 13:14:50 +0000[diff] [blame]4424 &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]4425</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4426
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4427</div>
4428
4429<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4430<h4>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4431 <a name="i_shufflevector">'<tt>shufflevector</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4432</h4>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4433
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4434<div>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4435
4436<h5>Syntax:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4437<pre>
Mon P Wangaeb06d22008-11-10 04:46:22 +0000[diff] [blame]4438 &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]4439</pre>
4440
4441<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4442<p>The '<tt>shufflevector</tt>' instruction constructs a permutation of elements
4443 from two input vectors, returning a vector with the same element type as the
4444 input and length that is the same as the shuffle mask.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4445
4446<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4447<p>The first two operands of a '<tt>shufflevector</tt>' instruction are vectors
4448 with types that match each other. The third argument is a shuffle mask whose
4449 element type is always 'i32'. The result of the instruction is a vector
4450 whose length is the same as the shuffle mask and whose element type is the
4451 same as the element type of the first two operands.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4452
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4453<p>The shuffle mask operand is required to be a constant vector with either
4454 constant integer or undef values.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4455
4456<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4457<p>The elements of the two input vectors are numbered from left to right across
4458 both of the vectors. The shuffle mask operand specifies, for each element of
4459 the result vector, which element of the two input vectors the result element
4460 gets. The element selector may be undef (meaning "don't care") and the
4461 second operand may be undef if performing a shuffle from only one vector.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4462
4463<h5>Example:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4464<pre>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4465 &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]4466 &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]4467 &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]4468 &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]4469 &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]4470 &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]4471 &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]4472 &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]4473</pre>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4474
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4475</div>
Tanya Lattner09474292006-04-14 19:24:33 +0000[diff] [blame]4476
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4477</div>
4478
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4479<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4480<h3>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4481 <a name="aggregateops">Aggregate Operations</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4482</h3>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4483
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4484<div>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4485
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4486<p>LLVM supports several instructions for working with
4487 <a href="#t_aggregate">aggregate</a> values.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4488
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4489<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4490<h4>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4491 <a name="i_extractvalue">'<tt>extractvalue</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4492</h4>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4493
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4494<div>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4495
4496<h5>Syntax:</h5>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4497<pre>
4498 &lt;result&gt; = extractvalue &lt;aggregate type&gt; &lt;val&gt;, &lt;idx&gt;{, &lt;idx&gt;}*
4499</pre>
4500
4501<h5>Overview:</h5>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4502<p>The '<tt>extractvalue</tt>' instruction extracts the value of a member field
4503 from an <a href="#t_aggregate">aggregate</a> value.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4504
4505<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4506<p>The first operand of an '<tt>extractvalue</tt>' instruction is a value
Chris Lattner61c70e92010-08-28 04:09:24 +0000[diff] [blame]4507 of <a href="#t_struct">struct</a> or
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4508 <a href="#t_array">array</a> type. The operands are constant indices to
4509 specify which value to extract in a similar manner as indices in a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4510 '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
Frits van Bommel13242892010-12-05 20:54:38 +0000[diff] [blame]4511 <p>The major differences to <tt>getelementptr</tt> indexing are:</p>
4512 <ul>
4513 <li>Since the value being indexed is not a pointer, the first index is
4514 omitted and assumed to be zero.</li>
4515 <li>At least one index must be specified.</li>
4516 <li>Not only struct indices but also array indices must be in
4517 bounds.</li>
4518 </ul>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4519
4520<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4521<p>The result is the value at the position in the aggregate specified by the
4522 index operands.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4523
4524<h5>Example:</h5>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4525<pre>
Gabor Greifa5b6f452009-10-28 13:14:50 +0000[diff] [blame]4526 &lt;result&gt; = extractvalue {i32, float} %agg, 0 <i>; yields i32</i>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4527</pre>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4528
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4529</div>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4530
4531<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4532<h4>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4533 <a name="i_insertvalue">'<tt>insertvalue</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4534</h4>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4535
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4536<div>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4537
4538<h5>Syntax:</h5>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4539<pre>
Bill Wendling194229e2011-07-26 20:42:28 +0000[diff] [blame]4540 &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]4541</pre>
4542
4543<h5>Overview:</h5>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4544<p>The '<tt>insertvalue</tt>' instruction inserts a value into a member field
4545 in an <a href="#t_aggregate">aggregate</a> value.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4546
4547<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4548<p>The first operand of an '<tt>insertvalue</tt>' instruction is a value
Chris Lattner61c70e92010-08-28 04:09:24 +0000[diff] [blame]4549 of <a href="#t_struct">struct</a> or
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4550 <a href="#t_array">array</a> type. The second operand is a first-class
4551 value to insert. The following operands are constant indices indicating
4552 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]4553 '<tt><a href="#i_extractvalue">extractvalue</a></tt>' instruction. The
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4554 value to insert must have the same type as the value identified by the
4555 indices.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4556
4557<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4558<p>The result is an aggregate of the same type as <tt>val</tt>. Its value is
4559 that of <tt>val</tt> except that the value at the position specified by the
4560 indices is that of <tt>elt</tt>.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4561
4562<h5>Example:</h5>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4563<pre>
Chris Lattner8645d1a2011-05-22 07:18:08 +0000[diff] [blame]4564 %agg1 = insertvalue {i32, float} undef, i32 1, 0 <i>; yields {i32 1, float undef}</i>
4565 %agg2 = insertvalue {i32, float} %agg1, float %val, 1 <i>; yields {i32 1, float %val}</i>
4566 %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]4567</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4568
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4569</div>
4570
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4571</div>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4572
4573<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4574<h3>
Chris Lattner884a9702006-08-15 00:45:58 +0000[diff] [blame]4575 <a name="memoryops">Memory Access and Addressing Operations</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4576</h3>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4577
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4578<div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4579
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4580<p>A key design point of an SSA-based representation is how it represents
4581 memory. In LLVM, no memory locations are in SSA form, which makes things
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]4582 very simple. This section describes how to read, write, and allocate
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4583 memory in LLVM.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4584
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4585<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4586<h4>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4587 <a name="i_alloca">'<tt>alloca</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4588</h4>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4589
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4590<div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4591
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4592<h5>Syntax:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4593<pre>
Dan Gohmanf75a7d32010-05-28 01:14:11 +0000[diff] [blame]4594 &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]4595</pre>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4596
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4597<h5>Overview:</h5>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]4598<p>The '<tt>alloca</tt>' instruction allocates memory on the stack frame of the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4599 currently executing function, to be automatically released when this function
4600 returns to its caller. The object is always allocated in the generic address
4601 space (address space zero).</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4602
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4603<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4604<p>The '<tt>alloca</tt>' instruction
4605 allocates <tt>sizeof(&lt;type&gt;)*NumElements</tt> bytes of memory on the
4606 runtime stack, returning a pointer of the appropriate type to the program.
4607 If "NumElements" is specified, it is the number of elements allocated,
4608 otherwise "NumElements" is defaulted to be one. If a constant alignment is
4609 specified, the value result of the allocation is guaranteed to be aligned to
4610 at least that boundary. If not specified, or if zero, the target can choose
4611 to align the allocation on any convenient boundary compatible with the
4612 type.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4613
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4614<p>'<tt>type</tt>' may be any sized type.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4615
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4616<h5>Semantics:</h5>
Bill Wendling871eb0a2009-05-08 20:49:29 +0000[diff] [blame]4617<p>Memory is allocated; a pointer is returned. The operation is undefined if
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4618 there is insufficient stack space for the allocation. '<tt>alloca</tt>'d
4619 memory is automatically released when the function returns. The
4620 '<tt>alloca</tt>' instruction is commonly used to represent automatic
4621 variables that must have an address available. When the function returns
4622 (either with the <tt><a href="#i_ret">ret</a></tt>
4623 or <tt><a href="#i_unwind">unwind</a></tt> instructions), the memory is
4624 reclaimed. Allocating zero bytes is legal, but the result is undefined.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4625
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4626<h5>Example:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4627<pre>
Dan Gohman81e21672009-01-04 23:49:44 +0000[diff] [blame]4628 %ptr = alloca i32 <i>; yields {i32*}:ptr</i>
4629 %ptr = alloca i32, i32 4 <i>; yields {i32*}:ptr</i>
4630 %ptr = alloca i32, i32 4, align 1024 <i>; yields {i32*}:ptr</i>
4631 %ptr = alloca i32, align 1024 <i>; yields {i32*}:ptr</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4632</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4633
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4634</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4635
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4636<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4637<h4>
4638 <a name="i_load">'<tt>load</tt>' Instruction</a>
4639</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4640
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4641<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4642
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4643<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4644<pre>
Eli Friedmanf03bb262011-08-12 22:50:01 +0000[diff] [blame]4645 &lt;result&gt; = load [volatile] &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;][, !nontemporal !&lt;index&gt;]
4646 &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]4647 !&lt;index&gt; = !{ i32 1 }
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4648</pre>
4649
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4650<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4651<p>The '<tt>load</tt>' instruction is used to read from memory.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4652
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4653<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4654<p>The argument to the '<tt>load</tt>' instruction specifies the memory address
4655 from which to load. The pointer must point to
4656 a <a href="#t_firstclass">first class</a> type. If the <tt>load</tt> is
4657 marked as <tt>volatile</tt>, then the optimizer is not allowed to modify the
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]4658 number or order of execution of this <tt>load</tt> with other <a
4659 href="#volatile">volatile operations</a>.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4660
Eli Friedman21006d42011-08-09 23:02:53 +0000[diff] [blame]4661<p>If the <code>load</code> is marked as <code>atomic</code>, it takes an extra
4662 <a href="#ordering">ordering</a> and optional <code>singlethread</code>
4663 argument. The <code>release</code> and <code>acq_rel</code> orderings are
4664 not valid on <code>load</code> instructions. Atomic loads produce <a
4665 href="#memorymodel">defined</a> results when they may see multiple atomic
4666 stores. The type of the pointee must be an integer type whose bit width
4667 is a power of two greater than or equal to eight and less than or equal
4668 to a target-specific size limit. <code>align</code> must be explicitly
4669 specified on atomic loads, and the load has undefined behavior if the
4670 alignment is not set to a value which is at least the size in bytes of
4671 the pointee. <code>!nontemporal</code> does not have any defined semantics
4672 for atomic loads.</p>
4673
Bill Wendling7c78dbb2010-02-25 21:23:24 +0000[diff] [blame]4674<p>The optional constant <tt>align</tt> argument specifies the alignment of the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4675 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]4676 omitted <tt>align</tt> argument means that the operation has the preferential
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4677 alignment for the target. It is the responsibility of the code emitter to
4678 ensure that the alignment information is correct. Overestimating the
Bill Wendling7c78dbb2010-02-25 21:23:24 +0000[diff] [blame]4679 alignment results in undefined behavior. Underestimating the alignment may
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4680 produce less efficient code. An alignment of 1 is always safe.</p>
4681
Bill Wendling7c78dbb2010-02-25 21:23:24 +0000[diff] [blame]4682<p>The optional <tt>!nontemporal</tt> metadata must reference a single
4683 metatadata name &lt;index&gt; corresponding to a metadata node with
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]4684 one <tt>i32</tt> entry of value 1. The existence of
Bill Wendling7c78dbb2010-02-25 21:23:24 +0000[diff] [blame]4685 the <tt>!nontemporal</tt> metatadata on the instruction tells the optimizer
4686 and code generator that this load is not expected to be reused in the cache.
4687 The code generator may select special instructions to save cache bandwidth,
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]4688 such as the <tt>MOVNT</tt> instruction on x86.</p>
David Greene8939b0d2010-02-16 20:50:18 +0000[diff] [blame]4689
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4690<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4691<p>The location of memory pointed to is loaded. If the value being loaded is of
4692 scalar type then the number of bytes read does not exceed the minimum number
4693 of bytes needed to hold all bits of the type. For example, loading an
4694 <tt>i24</tt> reads at most three bytes. When loading a value of a type like
4695 <tt>i20</tt> with a size that is not an integral number of bytes, the result
4696 is undefined if the value was not originally written using a store of the
4697 same type.</p>
4698
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4699<h5>Examples:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4700<pre>
4701 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
4702 <a href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4703 %val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4704</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4705
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4706</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4707
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4708<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4709<h4>
4710 <a name="i_store">'<tt>store</tt>' Instruction</a>
4711</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4712
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4713<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4714
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4715<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4716<pre>
Eli Friedmanf03bb262011-08-12 22:50:01 +0000[diff] [blame]4717 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>
4718 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]4719</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4720
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4721<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4722<p>The '<tt>store</tt>' instruction is used to write to memory.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4723
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4724<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4725<p>There are two arguments to the '<tt>store</tt>' instruction: a value to store
4726 and an address at which to store it. The type of the
4727 '<tt>&lt;pointer&gt;</tt>' operand must be a pointer to
4728 the <a href="#t_firstclass">first class</a> type of the
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]4729 '<tt>&lt;value&gt;</tt>' operand. If the <tt>store</tt> is marked as
4730 <tt>volatile</tt>, then the optimizer is not allowed to modify the number or
4731 order of execution of this <tt>store</tt> with other <a
4732 href="#volatile">volatile operations</a>.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4733
Eli Friedman21006d42011-08-09 23:02:53 +0000[diff] [blame]4734<p>If the <code>store</code> is marked as <code>atomic</code>, it takes an extra
4735 <a href="#ordering">ordering</a> and optional <code>singlethread</code>
4736 argument. The <code>acquire</code> and <code>acq_rel</code> orderings aren't
4737 valid on <code>store</code> instructions. Atomic loads produce <a
4738 href="#memorymodel">defined</a> results when they may see multiple atomic
4739 stores. The type of the pointee must be an integer type whose bit width
4740 is a power of two greater than or equal to eight and less than or equal
4741 to a target-specific size limit. <code>align</code> must be explicitly
4742 specified on atomic stores, and the store has undefined behavior if the
4743 alignment is not set to a value which is at least the size in bytes of
4744 the pointee. <code>!nontemporal</code> does not have any defined semantics
4745 for atomic stores.</p>
4746
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4747<p>The optional constant "align" argument specifies the alignment of the
4748 operation (that is, the alignment of the memory address). A value of 0 or an
4749 omitted "align" argument means that the operation has the preferential
4750 alignment for the target. It is the responsibility of the code emitter to
4751 ensure that the alignment information is correct. Overestimating the
4752 alignment results in an undefined behavior. Underestimating the alignment may
4753 produce less efficient code. An alignment of 1 is always safe.</p>
4754
David Greene8939b0d2010-02-16 20:50:18 +0000[diff] [blame]4755<p>The optional !nontemporal metadata must reference a single metatadata
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]4756 name &lt;index&gt; corresponding to a metadata node with one i32 entry of
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]4757 value 1. The existence of the !nontemporal metatadata on the
David Greene8939b0d2010-02-16 20:50:18 +0000[diff] [blame]4758 instruction tells the optimizer and code generator that this load is
4759 not expected to be reused in the cache. The code generator may
4760 select special instructions to save cache bandwidth, such as the
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]4761 MOVNT instruction on x86.</p>
David Greene8939b0d2010-02-16 20:50:18 +0000[diff] [blame]4762
4763
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4764<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4765<p>The contents of memory are updated to contain '<tt>&lt;value&gt;</tt>' at the
4766 location specified by the '<tt>&lt;pointer&gt;</tt>' operand. If
4767 '<tt>&lt;value&gt;</tt>' is of scalar type then the number of bytes written
4768 does not exceed the minimum number of bytes needed to hold all bits of the
4769 type. For example, storing an <tt>i24</tt> writes at most three bytes. When
4770 writing a value of a type like <tt>i20</tt> with a size that is not an
4771 integral number of bytes, it is unspecified what happens to the extra bits
4772 that do not belong to the type, but they will typically be overwritten.</p>
4773
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4774<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4775<pre>
4776 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Bill Wendling8c6c72d2007-10-22 05:10:05 +0000[diff] [blame]4777 store i32 3, i32* %ptr <i>; yields {void}</i>
4778 %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]4779</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4780
Reid Spencer47ce1792006-11-09 21:15:49 +0000[diff] [blame]4781</div>
4782
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4783<!-- _______________________________________________________________________ -->
NAKAMURA Takumib5bb29c2011-08-12 06:17:17 +0000[diff] [blame]4784<h4>
4785<a name="i_fence">'<tt>fence</tt>' Instruction</a>
4786</h4>
Eli Friedman47f35132011-07-25 23:16:38 +0000[diff] [blame]4787
NAKAMURA Takumib5bb29c2011-08-12 06:17:17 +0000[diff] [blame]4788<div>
Eli Friedman47f35132011-07-25 23:16:38 +0000[diff] [blame]4789
4790<h5>Syntax:</h5>
4791<pre>
4792 fence [singlethread] &lt;ordering&gt; <i>; yields {void}</i>
4793</pre>
4794
4795<h5>Overview:</h5>
4796<p>The '<tt>fence</tt>' instruction is used to introduce happens-before edges
4797between operations.</p>
4798
4799<h5>Arguments:</h5> <p>'<code>fence</code>' instructions take an <a
4800href="#ordering">ordering</a> argument which defines what
4801<i>synchronizes-with</i> edges they add. They can only be given
4802<code>acquire</code>, <code>release</code>, <code>acq_rel</code>, and
4803<code>seq_cst</code> orderings.</p>
4804
4805<h5>Semantics:</h5>
4806<p>A fence <var>A</var> which has (at least) <code>release</code> ordering
4807semantics <i>synchronizes with</i> a fence <var>B</var> with (at least)
4808<code>acquire</code> ordering semantics if and only if there exist atomic
4809operations <var>X</var> and <var>Y</var>, both operating on some atomic object
4810<var>M</var>, such that <var>A</var> is sequenced before <var>X</var>,
4811<var>X</var> modifies <var>M</var> (either directly or through some side effect
4812of a sequence headed by <var>X</var>), <var>Y</var> is sequenced before
4813<var>B</var>, and <var>Y</var> observes <var>M</var>. This provides a
4814<i>happens-before</i> dependency between <var>A</var> and <var>B</var>. Rather
4815than an explicit <code>fence</code>, one (but not both) of the atomic operations
4816<var>X</var> or <var>Y</var> might provide a <code>release</code> or
4817<code>acquire</code> (resp.) ordering constraint and still
4818<i>synchronize-with</i> the explicit <code>fence</code> and establish the
4819<i>happens-before</i> edge.</p>
4820
4821<p>A <code>fence</code> which has <code>seq_cst</code> ordering, in addition to
4822having both <code>acquire</code> and <code>release</code> semantics specified
4823above, participates in the global program order of other <code>seq_cst</code>
4824operations and/or fences.</p>
4825
4826<p>The optional "<a href="#singlethread"><code>singlethread</code></a>" argument
4827specifies that the fence only synchronizes with other fences in the same
4828thread. (This is useful for interacting with signal handlers.)</p>
4829
Eli Friedman47f35132011-07-25 23:16:38 +0000[diff] [blame]4830<h5>Example:</h5>
4831<pre>
4832 fence acquire <i>; yields {void}</i>
4833 fence singlethread seq_cst <i>; yields {void}</i>
4834</pre>
4835
4836</div>
4837
4838<!-- _______________________________________________________________________ -->
NAKAMURA Takumib5bb29c2011-08-12 06:17:17 +0000[diff] [blame]4839<h4>
4840<a name="i_cmpxchg">'<tt>cmpxchg</tt>' Instruction</a>
4841</h4>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]4842
NAKAMURA Takumib5bb29c2011-08-12 06:17:17 +0000[diff] [blame]4843<div>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]4844
4845<h5>Syntax:</h5>
4846<pre>
Eli Friedmanf03bb262011-08-12 22:50:01 +0000[diff] [blame]4847 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]4848</pre>
4849
4850<h5>Overview:</h5>
4851<p>The '<tt>cmpxchg</tt>' instruction is used to atomically modify memory.
4852It loads a value in memory and compares it to a given value. If they are
4853equal, it stores a new value into the memory.</p>
4854
4855<h5>Arguments:</h5>
4856<p>There are three arguments to the '<code>cmpxchg</code>' instruction: an
4857address to operate on, a value to compare to the value currently be at that
4858address, and a new value to place at that address if the compared values are
4859equal. The type of '<var>&lt;cmp&gt;</var>' must be an integer type whose
4860bit width is a power of two greater than or equal to eight and less than
4861or equal to a target-specific size limit. '<var>&lt;cmp&gt;</var>' and
4862'<var>&lt;new&gt;</var>' must have the same type, and the type of
4863'<var>&lt;pointer&gt;</var>' must be a pointer to that type. If the
4864<code>cmpxchg</code> is marked as <code>volatile</code>, then the
4865optimizer is not allowed to modify the number or order of execution
4866of this <code>cmpxchg</code> with other <a href="#volatile">volatile
4867operations</a>.</p>
4868
4869<!-- FIXME: Extend allowed types. -->
4870
4871<p>The <a href="#ordering"><var>ordering</var></a> argument specifies how this
4872<code>cmpxchg</code> synchronizes with other atomic operations.</p>
4873
4874<p>The optional "<code>singlethread</code>" argument declares that the
4875<code>cmpxchg</code> is only atomic with respect to code (usually signal
4876handlers) running in the same thread as the <code>cmpxchg</code>. Otherwise the
4877cmpxchg is atomic with respect to all other code in the system.</p>
4878
4879<p>The pointer passed into cmpxchg must have alignment greater than or equal to
4880the size in memory of the operand.
4881
4882<h5>Semantics:</h5>
4883<p>The contents of memory at the location specified by the
4884'<tt>&lt;pointer&gt;</tt>' operand is read and compared to
4885'<tt>&lt;cmp&gt;</tt>'; if the read value is the equal,
4886'<tt>&lt;new&gt;</tt>' is written. The original value at the location
4887is returned.
4888
4889<p>A successful <code>cmpxchg</code> is a read-modify-write instruction for the
4890purpose of identifying <a href="#release_sequence">release sequences</a>. A
4891failed <code>cmpxchg</code> is equivalent to an atomic load with an ordering
4892parameter determined by dropping any <code>release</code> part of the
4893<code>cmpxchg</code>'s ordering.</p>
4894
4895<!--
4896FIXME: Is compare_exchange_weak() necessary? (Consider after we've done
4897optimization work on ARM.)
4898
4899FIXME: Is a weaker ordering constraint on failure helpful in practice?
4900-->
4901
4902<h5>Example:</h5>
4903<pre>
4904entry:
4905 %orig = atomic <a href="#i_load">load</a> i32* %ptr unordered <i>; yields {i32}</i>
4906 <a href="#i_br">br</a> label %loop
4907
4908loop:
4909 %cmp = <a href="#i_phi">phi</a> i32 [ %orig, %entry ], [%old, %loop]
4910 %squared = <a href="#i_mul">mul</a> i32 %cmp, %cmp
4911 %old = cmpxchg i32* %ptr, i32 %cmp, i32 %squared <i>; yields {i32}</i>
4912 %success = <a href="#i_icmp">icmp</a> eq i32 %cmp, %old
4913 <a href="#i_br">br</a> i1 %success, label %done, label %loop
4914
4915done:
4916 ...
4917</pre>
4918
4919</div>
4920
4921<!-- _______________________________________________________________________ -->
NAKAMURA Takumib5bb29c2011-08-12 06:17:17 +0000[diff] [blame]4922<h4>
4923<a name="i_atomicrmw">'<tt>atomicrmw</tt>' Instruction</a>
4924</h4>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]4925
NAKAMURA Takumib5bb29c2011-08-12 06:17:17 +0000[diff] [blame]4926<div>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]4927
4928<h5>Syntax:</h5>
4929<pre>
Eli Friedmanf03bb262011-08-12 22:50:01 +0000[diff] [blame]4930 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]4931</pre>
4932
4933<h5>Overview:</h5>
4934<p>The '<tt>atomicrmw</tt>' instruction is used to atomically modify memory.</p>
4935
4936<h5>Arguments:</h5>
4937<p>There are three arguments to the '<code>atomicrmw</code>' instruction: an
4938operation to apply, an address whose value to modify, an argument to the
4939operation. The operation must be one of the following keywords:</p>
4940<ul>
4941 <li>xchg</li>
4942 <li>add</li>
4943 <li>sub</li>
4944 <li>and</li>
4945 <li>nand</li>
4946 <li>or</li>
4947 <li>xor</li>
4948 <li>max</li>
4949 <li>min</li>
4950 <li>umax</li>
4951 <li>umin</li>
4952</ul>
4953
4954<p>The type of '<var>&lt;value&gt;</var>' must be an integer type whose
4955bit width is a power of two greater than or equal to eight and less than
4956or equal to a target-specific size limit. The type of the
4957'<code>&lt;pointer&gt;</code>' operand must be a pointer to that type.
4958If the <code>atomicrmw</code> is marked as <code>volatile</code>, then the
4959optimizer is not allowed to modify the number or order of execution of this
4960<code>atomicrmw</code> with other <a href="#volatile">volatile
4961 operations</a>.</p>
4962
4963<!-- FIXME: Extend allowed types. -->
4964
4965<h5>Semantics:</h5>
4966<p>The contents of memory at the location specified by the
4967'<tt>&lt;pointer&gt;</tt>' operand are atomically read, modified, and written
4968back. The original value at the location is returned. The modification is
4969specified by the <var>operation</var> argument:</p>
4970
4971<ul>
4972 <li>xchg: <code>*ptr = val</code></li>
4973 <li>add: <code>*ptr = *ptr + val</code></li>
4974 <li>sub: <code>*ptr = *ptr - val</code></li>
4975 <li>and: <code>*ptr = *ptr &amp; val</code></li>
4976 <li>nand: <code>*ptr = ~(*ptr &amp; val)</code></li>
4977 <li>or: <code>*ptr = *ptr | val</code></li>
4978 <li>xor: <code>*ptr = *ptr ^ val</code></li>
4979 <li>max: <code>*ptr = *ptr &gt; val ? *ptr : val</code> (using a signed comparison)</li>
4980 <li>min: <code>*ptr = *ptr &lt; val ? *ptr : val</code> (using a signed comparison)</li>
4981 <li>umax: <code>*ptr = *ptr &gt; val ? *ptr : val</code> (using an unsigned comparison)</li>
4982 <li>umin: <code>*ptr = *ptr &lt; val ? *ptr : val</code> (using an unsigned comparison)</li>
4983</ul>
4984
4985<h5>Example:</h5>
4986<pre>
4987 %old = atomicrmw add i32* %ptr, i32 1 acquire <i>; yields {i32}</i>
4988</pre>
4989
4990</div>
4991
4992<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4993<h4>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4994 <a name="i_getelementptr">'<tt>getelementptr</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4995</h4>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4996
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4997<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4998
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]4999<h5>Syntax:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5000<pre>
Matthijs Kooijmane49d0bc2008-10-13 13:44:15 +0000[diff] [blame]5001 &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]5002 &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]5003</pre>
5004
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]5005<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5006<p>The '<tt>getelementptr</tt>' instruction is used to get the address of a
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]5007 subelement of an <a href="#t_aggregate">aggregate</a> data structure.
5008 It performs address calculation only and does not access memory.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5009
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]5010<h5>Arguments:</h5>
Matthijs Kooijmane49d0bc2008-10-13 13:44:15 +0000[diff] [blame]5011<p>The first argument is always a pointer, and forms the basis of the
Chris Lattnerc8eef442009-07-29 06:44:13 +0000[diff] [blame]5012 calculation. The remaining arguments are indices that indicate which of the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5013 elements of the aggregate object are indexed. The interpretation of each
5014 index is dependent on the type being indexed into. The first index always
5015 indexes the pointer value given as the first argument, the second index
5016 indexes a value of the type pointed to (not necessarily the value directly
5017 pointed to, since the first index can be non-zero), etc. The first type
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]5018 indexed into must be a pointer value, subsequent types can be arrays,
Chris Lattner61c70e92010-08-28 04:09:24 +0000[diff] [blame]5019 vectors, and structs. Note that subsequent types being indexed into
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]5020 can never be pointers, since that would require loading the pointer before
5021 continuing calculation.</p>
Matthijs Kooijmane49d0bc2008-10-13 13:44:15 +0000[diff] [blame]5022
5023<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]5024 When indexing into a (optionally packed) structure, only <tt>i32</tt>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]5025 integer <b>constants</b> are allowed. When indexing into an array, pointer
5026 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]5027 constant. These integers are treated as signed values where relevant.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5028
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5029<p>For example, let's consider a C code fragment and how it gets compiled to
5030 LLVM:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5031
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]5032<pre class="doc_code">
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]5033struct RT {
5034 char A;
Chris Lattnercabc8462007-05-29 15:43:56 +0000[diff] [blame]5035 int B[10][20];
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]5036 char C;
5037};
5038struct ST {
Chris Lattnercabc8462007-05-29 15:43:56 +0000[diff] [blame]5039 int X;
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]5040 double Y;
5041 struct RT Z;
5042};
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5043
Chris Lattnercabc8462007-05-29 15:43:56 +0000[diff] [blame]5044int *foo(struct ST *s) {
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]5045 return &amp;s[1].Z.B[5][13];
5046}
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5047</pre>
5048
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5049<p>The LLVM code generated by the GCC frontend is:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5050
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]5051<pre class="doc_code">
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]5052%RT = <a href="#namedtypes">type</a> { i8 , [10 x [20 x i32]], i8 }
5053%ST = <a href="#namedtypes">type</a> { i32, double, %RT }
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5054
Dan Gohman4df605b2009-07-25 02:23:48 +0000[diff] [blame]5055define i32* @foo(%ST* %s) {
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]5056entry:
5057 %reg = getelementptr %ST* %s, i32 1, i32 2, i32 1, i32 5, i32 13
5058 ret i32* %reg
5059}
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5060</pre>
5061
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]5062<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5063<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]5064 type, which is a pointer, yielding a '<tt>%ST</tt>' = '<tt>{ i32, double, %RT
5065 }</tt>' type, a structure. The second index indexes into the third element
5066 of the structure, yielding a '<tt>%RT</tt>' = '<tt>{ i8 , [10 x [20 x i32]],
5067 i8 }</tt>' type, another structure. The third index indexes into the second
5068 element of the structure, yielding a '<tt>[10 x [20 x i32]]</tt>' type, an
5069 array. The two dimensions of the array are subscripted into, yielding an
5070 '<tt>i32</tt>' type. The '<tt>getelementptr</tt>' instruction returns a
5071 pointer to this element, thus computing a value of '<tt>i32*</tt>' type.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5072
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5073<p>Note that it is perfectly legal to index partially through a structure,
5074 returning a pointer to an inner element. Because of this, the LLVM code for
5075 the given testcase is equivalent to:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5076
5077<pre>
Dan Gohman4df605b2009-07-25 02:23:48 +0000[diff] [blame]5078 define i32* @foo(%ST* %s) {
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5079 %t1 = getelementptr %ST* %s, i32 1 <i>; yields %ST*:%t1</i>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]5080 %t2 = getelementptr %ST* %t1, i32 0, i32 2 <i>; yields %RT*:%t2</i>
5081 %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]5082 %t4 = getelementptr [10 x [20 x i32]]* %t3, i32 0, i32 5 <i>; yields [20 x i32]*:%t4</i>
5083 %t5 = getelementptr [20 x i32]* %t4, i32 0, i32 13 <i>; yields i32*:%t5</i>
5084 ret i32* %t5
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5085 }
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]5086</pre>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]5087
Dan Gohmandd8004d2009-07-27 21:53:46 +0000[diff] [blame]5088<p>If the <tt>inbounds</tt> keyword is present, the result value of the
Dan Gohman27ef9972010-04-23 15:23:32 +0000[diff] [blame]5089 <tt>getelementptr</tt> is a <a href="#trapvalues">trap value</a> if the
5090 base pointer is not an <i>in bounds</i> address of an allocated object,
5091 or if any of the addresses that would be formed by successive addition of
5092 the offsets implied by the indices to the base address with infinitely
Eli Friedman266246c2011-08-12 23:37:55 +0000[diff] [blame]5093 precise signed arithmetic are not an <i>in bounds</i> address of that
5094 allocated object. The <i>in bounds</i> addresses for an allocated object
5095 are all the addresses that point into the object, plus the address one
5096 byte past the end.</p>
Dan Gohmandd8004d2009-07-27 21:53:46 +0000[diff] [blame]5097
5098<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]5099 the base address with silently-wrapping two's complement arithmetic. If the
5100 offsets have a different width from the pointer, they are sign-extended or
5101 truncated to the width of the pointer. The result value of the
5102 <tt>getelementptr</tt> may be outside the object pointed to by the base
5103 pointer. The result value may not necessarily be used to access memory
5104 though, even if it happens to point into allocated storage. See the
5105 <a href="#pointeraliasing">Pointer Aliasing Rules</a> section for more
5106 information.</p>
Dan Gohmandd8004d2009-07-27 21:53:46 +0000[diff] [blame]5107
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5108<p>The getelementptr instruction is often confusing. For some more insight into
5109 how it works, see <a href="GetElementPtr.html">the getelementptr FAQ</a>.</p>
Chris Lattner884a9702006-08-15 00:45:58 +0000[diff] [blame]5110
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]5111<h5>Example:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5112<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5113 <i>; yields [12 x i8]*:aptr</i>
Matthijs Kooijmane49d0bc2008-10-13 13:44:15 +0000[diff] [blame]5114 %aptr = getelementptr {i32, [12 x i8]}* %saptr, i64 0, i32 1
5115 <i>; yields i8*:vptr</i>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]5116 %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]5117 <i>; yields i8*:eptr</i>
5118 %eptr = getelementptr [12 x i8]* %aptr, i64 0, i32 1
Sanjiv Gupta9f805c22009-04-25 07:27:44 +0000[diff] [blame]5119 <i>; yields i32*:iptr</i>
Sanjiv Gupta16ffa802009-04-24 16:38:13 +0000[diff] [blame]5120 %iptr = getelementptr [10 x i32]* @arr, i16 0, i16 0
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5121</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5122
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5123</div>
Reid Spencer47ce1792006-11-09 21:15:49 +0000[diff] [blame]5124
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5125</div>
5126
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]5127<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5128<h3>
5129 <a name="convertops">Conversion Operations</a>
5130</h3>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5131
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5132<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5133
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5134<p>The instructions in this category are the conversion instructions (casting)
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5135 which all take a single operand and a type. They perform various bit
5136 conversions on the operand.</p>
5137
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]5138<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5139<h4>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5140 <a name="i_trunc">'<tt>trunc .. to</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5141</h4>
5142
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5143<div>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5144
5145<h5>Syntax:</h5>
5146<pre>
5147 &lt;result&gt; = trunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
5148</pre>
5149
5150<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5151<p>The '<tt>trunc</tt>' instruction truncates its operand to the
5152 type <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5153
5154<h5>Arguments:</h5>
Nadav Rotem8c20ec52011-02-24 21:01:34 +0000[diff] [blame]5155<p>The '<tt>trunc</tt>' instruction takes a value to trunc, and a type to trunc it to.
5156 Both types must be of <a href="#t_integer">integer</a> types, or vectors
5157 of the same number of integers.
5158 The bit size of the <tt>value</tt> must be larger than
5159 the bit size of the destination type, <tt>ty2</tt>.
5160 Equal sized types are not allowed.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5161
5162<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5163<p>The '<tt>trunc</tt>' instruction truncates the high order bits
5164 in <tt>value</tt> and converts the remaining bits to <tt>ty2</tt>. Since the
5165 source size must be larger than the destination size, <tt>trunc</tt> cannot
5166 be a <i>no-op cast</i>. It will always truncate bits.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5167
5168<h5>Example:</h5>
5169<pre>
Nadav Rotem8c20ec52011-02-24 21:01:34 +0000[diff] [blame]5170 %X = trunc i32 257 to i8 <i>; yields i8:1</i>
5171 %Y = trunc i32 123 to i1 <i>; yields i1:true</i>
5172 %Z = trunc i32 122 to i1 <i>; yields i1:false</i>
5173 %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]5174</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5175
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5176</div>
5177
5178<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5179<h4>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5180 <a name="i_zext">'<tt>zext .. to</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5181</h4>
5182
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5183<div>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5184
5185<h5>Syntax:</h5>
5186<pre>
5187 &lt;result&gt; = zext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
5188</pre>
5189
5190<h5>Overview:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5191<p>The '<tt>zext</tt>' instruction zero extends its operand to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5192 <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5193
5194
5195<h5>Arguments:</h5>
Nadav Rotemed9b9342011-02-20 12:37:50 +0000[diff] [blame]5196<p>The '<tt>zext</tt>' instruction takes a value to cast, and a type to cast it to.
5197 Both types must be of <a href="#t_integer">integer</a> types, or vectors
5198 of the same number of integers.
5199 The bit size of the <tt>value</tt> must be smaller than
5200 the bit size of the destination type,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5201 <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5202
5203<h5>Semantics:</h5>
5204<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]5205 bits until it reaches the size of the destination type, <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5206
Reid Spencerb5929522007-01-12 15:46:11 +0000[diff] [blame]5207<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]5208
5209<h5>Example:</h5>
5210<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5211 %X = zext i32 257 to i64 <i>; yields i64:257</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]5212 %Y = zext i1 true to i32 <i>; yields i32:1</i>
Nadav Rotemed9b9342011-02-20 12:37:50 +0000[diff] [blame]5213 %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]5214</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5215
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5216</div>
5217
5218<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5219<h4>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5220 <a name="i_sext">'<tt>sext .. to</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5221</h4>
5222
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5223<div>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5224
5225<h5>Syntax:</h5>
5226<pre>
5227 &lt;result&gt; = sext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
5228</pre>
5229
5230<h5>Overview:</h5>
5231<p>The '<tt>sext</tt>' sign extends <tt>value</tt> to the type <tt>ty2</tt>.</p>
5232
5233<h5>Arguments:</h5>
Nadav Rotem8c20ec52011-02-24 21:01:34 +0000[diff] [blame]5234<p>The '<tt>sext</tt>' instruction takes a value to cast, and a type to cast it to.
5235 Both types must be of <a href="#t_integer">integer</a> types, or vectors
5236 of the same number of integers.
5237 The bit size of the <tt>value</tt> must be smaller than
5238 the bit size of the destination type,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5239 <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5240
5241<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5242<p>The '<tt>sext</tt>' instruction performs a sign extension by copying the sign
5243 bit (highest order bit) of the <tt>value</tt> until it reaches the bit size
5244 of the type <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5245
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]5246<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]5247
5248<h5>Example:</h5>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5249<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5250 %X = sext i8 -1 to i16 <i>; yields i16 :65535</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]5251 %Y = sext i1 true to i32 <i>; yields i32:-1</i>
Nadav Rotem8c20ec52011-02-24 21:01:34 +0000[diff] [blame]5252 %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]5253</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5254
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5255</div>
5256
5257<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5258<h4>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]5259 <a name="i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5260</h4>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]5261
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5262<div>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]5263
5264<h5>Syntax:</h5>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]5265<pre>
5266 &lt;result&gt; = fptrunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
5267</pre>
5268
5269<h5>Overview:</h5>
5270<p>The '<tt>fptrunc</tt>' instruction truncates <tt>value</tt> to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5271 <tt>ty2</tt>.</p>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]5272
5273<h5>Arguments:</h5>
5274<p>The '<tt>fptrunc</tt>' instruction takes a <a href="#t_floating">floating
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5275 point</a> value to cast and a <a href="#t_floating">floating point</a> type
5276 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]5277 <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]5278 <i>no-op cast</i>.</p>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]5279
5280<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5281<p>The '<tt>fptrunc</tt>' instruction truncates a <tt>value</tt> from a larger
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5282 <a href="#t_floating">floating point</a> type to a smaller
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5283 <a href="#t_floating">floating point</a> type. If the value cannot fit
5284 within the destination type, <tt>ty2</tt>, then the results are
5285 undefined.</p>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]5286
5287<h5>Example:</h5>
5288<pre>
5289 %X = fptrunc double 123.0 to float <i>; yields float:123.0</i>
5290 %Y = fptrunc double 1.0E+300 to float <i>; yields undefined</i>
5291</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5292
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]5293</div>
5294
5295<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5296<h4>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5297 <a name="i_fpext">'<tt>fpext .. to</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5298</h4>
5299
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5300<div>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5301
5302<h5>Syntax:</h5>
5303<pre>
5304 &lt;result&gt; = fpext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
5305</pre>
5306
5307<h5>Overview:</h5>
5308<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]5309 floating point value.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5310
5311<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5312<p>The '<tt>fpext</tt>' instruction takes a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5313 <a href="#t_floating">floating point</a> <tt>value</tt> to cast, and
5314 a <a href="#t_floating">floating point</a> type to cast it to. The source
5315 type must be smaller than the destination type.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5316
5317<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]5318<p>The '<tt>fpext</tt>' instruction extends the <tt>value</tt> from a smaller
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5319 <a href="#t_floating">floating point</a> type to a larger
5320 <a href="#t_floating">floating point</a> type. The <tt>fpext</tt> cannot be
5321 used to make a <i>no-op cast</i> because it always changes bits. Use
5322 <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]5323
5324<h5>Example:</h5>
5325<pre>
Nick Lewycky5bb3ece2011-03-31 18:20:19 +0000[diff] [blame]5326 %X = fpext float 3.125 to double <i>; yields double:3.125000e+00</i>
5327 %Y = fpext double %X to fp128 <i>; yields fp128:0xL00000000000000004000900000000000</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5328</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5329
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5330</div>
5331
5332<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5333<h4>
Reid Spencer24d6da52007-01-21 00:29:26 +0000[diff] [blame]5334 <a name="i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5335</h4>
5336
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5337<div>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5338
5339<h5>Syntax:</h5>
5340<pre>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]5341 &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]5342</pre>
5343
5344<h5>Overview:</h5>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]5345<p>The '<tt>fptoui</tt>' converts a floating point <tt>value</tt> to its
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5346 unsigned integer equivalent of type <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5347
5348<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5349<p>The '<tt>fptoui</tt>' instruction takes a value to cast, which must be a
5350 scalar or vector <a href="#t_floating">floating point</a> value, and a type
5351 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
5352 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
5353 vector integer type with the same number of elements as <tt>ty</tt></p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5354
5355<h5>Semantics:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5356<p>The '<tt>fptoui</tt>' instruction converts its
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5357 <a href="#t_floating">floating point</a> operand into the nearest (rounding
5358 towards zero) unsigned integer value. If the value cannot fit
5359 in <tt>ty2</tt>, the results are undefined.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5360
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5361<h5>Example:</h5>
5362<pre>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]5363 %X = fptoui double 123.0 to i32 <i>; yields i32:123</i>
Chris Lattner88519042007-09-22 03:17:52 +0000[diff] [blame]5364 %Y = fptoui float 1.0E+300 to i1 <i>; yields undefined:1</i>
Gabor Greif6a292012009-10-28 09:21:30 +0000[diff] [blame]5365 %Z = fptoui float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5366</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5367
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5368</div>
5369
5370<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5371<h4>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]5372 <a name="i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5373</h4>
5374
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5375<div>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5376
5377<h5>Syntax:</h5>
5378<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]5379 &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]5380</pre>
5381
5382<h5>Overview:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5383<p>The '<tt>fptosi</tt>' instruction converts
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5384 <a href="#t_floating">floating point</a> <tt>value</tt> to
5385 type <tt>ty2</tt>.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5386
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]5387<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5388<p>The '<tt>fptosi</tt>' instruction takes a value to cast, which must be a
5389 scalar or vector <a href="#t_floating">floating point</a> value, and a type
5390 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
5391 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
5392 vector integer type with the same number of elements as <tt>ty</tt></p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5393
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]5394<h5>Semantics:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5395<p>The '<tt>fptosi</tt>' instruction converts its
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5396 <a href="#t_floating">floating point</a> operand into the nearest (rounding
5397 towards zero) signed integer value. If the value cannot fit in <tt>ty2</tt>,
5398 the results are undefined.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5399
Chris Lattner33ba0d92001-07-09 00:26:23 +0000[diff] [blame]5400<h5>Example:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5401<pre>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]5402 %X = fptosi double -123.0 to i32 <i>; yields i32:-123</i>
Chris Lattner88519042007-09-22 03:17:52 +0000[diff] [blame]5403 %Y = fptosi float 1.0E-247 to i1 <i>; yields undefined:1</i>
Gabor Greif6a292012009-10-28 09:21:30 +0000[diff] [blame]5404 %Z = fptosi float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5405</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5406
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5407</div>
5408
5409<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5410<h4>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]5411 <a name="i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5412</h4>
5413
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5414<div>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5415
5416<h5>Syntax:</h5>
5417<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]5418 &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]5419</pre>
5420
5421<h5>Overview:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]5422<p>The '<tt>uitofp</tt>' instruction regards <tt>value</tt> as an unsigned
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5423 integer and converts that value to the <tt>ty2</tt> type.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5424
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5425<h5>Arguments:</h5>
Nate Begemanb348d182007-11-17 03:58:34 +0000[diff] [blame]5426<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]5427 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
5428 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
5429 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
5430 floating point type with the same number of elements as <tt>ty</tt></p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5431
5432<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]5433<p>The '<tt>uitofp</tt>' instruction interprets its operand as an unsigned
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5434 integer quantity and converts it to the corresponding floating point
5435 value. If the value cannot fit in the floating point value, the results are
5436 undefined.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5437
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5438<h5>Example:</h5>
5439<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5440 %X = uitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]5441 %Y = uitofp i8 -1 to double <i>; yields double:255.0</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5442</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5443
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5444</div>
5445
5446<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5447<h4>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]5448 <a name="i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5449</h4>
5450
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5451<div>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5452
5453<h5>Syntax:</h5>
5454<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]5455 &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]5456</pre>
5457
5458<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5459<p>The '<tt>sitofp</tt>' instruction regards <tt>value</tt> as a signed integer
5460 and converts that value to the <tt>ty2</tt> type.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5461
5462<h5>Arguments:</h5>
Nate Begemanb348d182007-11-17 03:58:34 +0000[diff] [blame]5463<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]5464 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
5465 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
5466 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
5467 floating point type with the same number of elements as <tt>ty</tt></p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5468
5469<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5470<p>The '<tt>sitofp</tt>' instruction interprets its operand as a signed integer
5471 quantity and converts it to the corresponding floating point value. If the
5472 value cannot fit in the floating point value, the results are undefined.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5473
5474<h5>Example:</h5>
5475<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5476 %X = sitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]5477 %Y = sitofp i8 -1 to double <i>; yields double:-1.0</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5478</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5479
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5480</div>
5481
5482<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5483<h4>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]5484 <a name="i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5485</h4>
5486
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5487<div>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]5488
5489<h5>Syntax:</h5>
5490<pre>
5491 &lt;result&gt; = ptrtoint &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
5492</pre>
5493
5494<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5495<p>The '<tt>ptrtoint</tt>' instruction converts the pointer <tt>value</tt> to
5496 the integer type <tt>ty2</tt>.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]5497
5498<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5499<p>The '<tt>ptrtoint</tt>' instruction takes a <tt>value</tt> to cast, which
5500 must be a <a href="#t_pointer">pointer</a> value, and a type to cast it to
5501 <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]5502
5503<h5>Semantics:</h5>
5504<p>The '<tt>ptrtoint</tt>' instruction converts <tt>value</tt> to integer type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5505 <tt>ty2</tt> by interpreting the pointer value as an integer and either
5506 truncating or zero extending that value to the size of the integer type. If
5507 <tt>value</tt> is smaller than <tt>ty2</tt> then a zero extension is done. If
5508 <tt>value</tt> is larger than <tt>ty2</tt> then a truncation is done. If they
5509 are the same size, then nothing is done (<i>no-op cast</i>) other than a type
5510 change.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]5511
5512<h5>Example:</h5>
5513<pre>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5514 %X = ptrtoint i32* %X to i8 <i>; yields truncation on 32-bit architecture</i>
5515 %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]5516</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5517
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]5518</div>
5519
5520<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5521<h4>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]5522 <a name="i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5523</h4>
5524
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5525<div>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]5526
5527<h5>Syntax:</h5>
5528<pre>
5529 &lt;result&gt; = inttoptr &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
5530</pre>
5531
5532<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5533<p>The '<tt>inttoptr</tt>' instruction converts an integer <tt>value</tt> to a
5534 pointer type, <tt>ty2</tt>.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]5535
5536<h5>Arguments:</h5>
Duncan Sands8036ca42007-03-30 12:22:09 +0000[diff] [blame]5537<p>The '<tt>inttoptr</tt>' instruction takes an <a href="#t_integer">integer</a>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5538 value to cast, and a type to cast it to, which must be a
5539 <a href="#t_pointer">pointer</a> type.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]5540
5541<h5>Semantics:</h5>
5542<p>The '<tt>inttoptr</tt>' instruction converts <tt>value</tt> to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5543 <tt>ty2</tt> by applying either a zero extension or a truncation depending on
5544 the size of the integer <tt>value</tt>. If <tt>value</tt> is larger than the
5545 size of a pointer then a truncation is done. If <tt>value</tt> is smaller
5546 than the size of a pointer then a zero extension is done. If they are the
5547 same size, nothing is done (<i>no-op cast</i>).</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]5548
5549<h5>Example:</h5>
5550<pre>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5551 %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]5552 %Y = inttoptr i32 255 to i32* <i>; yields no-op on 32-bit architecture</i>
5553 %Z = inttoptr i64 0 to i32* <i>; yields truncation on 32-bit architecture</i>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]5554</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5555
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]5556</div>
5557
5558<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5559<h4>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]5560 <a name="i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5561</h4>
5562
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5563<div>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5564
5565<h5>Syntax:</h5>
5566<pre>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]5567 &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]5568</pre>
5569
5570<h5>Overview:</h5>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]5571<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5572 <tt>ty2</tt> without changing any bits.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5573
5574<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5575<p>The '<tt>bitcast</tt>' instruction takes a value to cast, which must be a
5576 non-aggregate first class value, and a type to cast it to, which must also be
5577 a non-aggregate <a href="#t_firstclass">first class</a> type. The bit sizes
5578 of <tt>value</tt> and the destination type, <tt>ty2</tt>, must be
5579 identical. If the source type is a pointer, the destination type must also be
5580 a pointer. This instruction supports bitwise conversion of vectors to
5581 integers and to vectors of other types (as long as they have the same
5582 size).</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5583
5584<h5>Semantics:</h5>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]5585<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5586 <tt>ty2</tt>. It is always a <i>no-op cast</i> because no bits change with
5587 this conversion. The conversion is done as if the <tt>value</tt> had been
5588 stored to memory and read back as type <tt>ty2</tt>. Pointer types may only
5589 be converted to other pointer types with this instruction. To convert
5590 pointers to other types, use the <a href="#i_inttoptr">inttoptr</a> or
5591 <a href="#i_ptrtoint">ptrtoint</a> instructions first.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5592
5593<h5>Example:</h5>
5594<pre>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5595 %X = bitcast i8 255 to i8 <i>; yields i8 :-1</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5596 %Y = bitcast i32* %x to sint* <i>; yields sint*:%x</i>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5597 %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]5598</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5599
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5600</div>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5601
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5602</div>
5603
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5604<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5605<h3>
5606 <a name="otherops">Other Operations</a>
5607</h3>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5608
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5609<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5610
5611<p>The instructions in this category are the "miscellaneous" instructions, which
5612 defy better classification.</p>
5613
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5614<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5615<h4>
5616 <a name="i_icmp">'<tt>icmp</tt>' Instruction</a>
5617</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5618
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5619<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5620
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5621<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5622<pre>
5623 &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]5624</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5625
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5626<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5627<p>The '<tt>icmp</tt>' instruction returns a boolean value or a vector of
5628 boolean values based on comparison of its two integer, integer vector, or
5629 pointer operands.</p>
5630
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5631<h5>Arguments:</h5>
5632<p>The '<tt>icmp</tt>' instruction takes three operands. The first operand is
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5633 the condition code indicating the kind of comparison to perform. It is not a
5634 value, just a keyword. The possible condition code are:</p>
5635
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5636<ol>
5637 <li><tt>eq</tt>: equal</li>
5638 <li><tt>ne</tt>: not equal </li>
5639 <li><tt>ugt</tt>: unsigned greater than</li>
5640 <li><tt>uge</tt>: unsigned greater or equal</li>
5641 <li><tt>ult</tt>: unsigned less than</li>
5642 <li><tt>ule</tt>: unsigned less or equal</li>
5643 <li><tt>sgt</tt>: signed greater than</li>
5644 <li><tt>sge</tt>: signed greater or equal</li>
5645 <li><tt>slt</tt>: signed less than</li>
5646 <li><tt>sle</tt>: signed less or equal</li>
5647</ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5648
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]5649<p>The remaining two arguments must be <a href="#t_integer">integer</a> or
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5650 <a href="#t_pointer">pointer</a> or integer <a href="#t_vector">vector</a>
5651 typed. They must also be identical types.</p>
5652
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5653<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5654<p>The '<tt>icmp</tt>' compares <tt>op1</tt> and <tt>op2</tt> according to the
5655 condition code given as <tt>cond</tt>. The comparison performed always yields
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]5656 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]5657 result, as follows:</p>
5658
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5659<ol>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5660 <li><tt>eq</tt>: yields <tt>true</tt> if the operands are equal,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5661 <tt>false</tt> otherwise. No sign interpretation is necessary or
5662 performed.</li>
5663
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5664 <li><tt>ne</tt>: yields <tt>true</tt> if the operands are unequal,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5665 <tt>false</tt> otherwise. No sign interpretation is necessary or
5666 performed.</li>
5667
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5668 <li><tt>ugt</tt>: interprets the operands as unsigned values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5669 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
5670
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5671 <li><tt>uge</tt>: interprets the operands as unsigned values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5672 <tt>true</tt> if <tt>op1</tt> is greater than or equal
5673 to <tt>op2</tt>.</li>
5674
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5675 <li><tt>ult</tt>: interprets the operands as unsigned values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5676 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
5677
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5678 <li><tt>ule</tt>: interprets the operands as unsigned values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5679 <tt>true</tt> if <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
5680
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5681 <li><tt>sgt</tt>: interprets the operands as signed values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5682 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
5683
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5684 <li><tt>sge</tt>: interprets the operands as signed values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5685 <tt>true</tt> if <tt>op1</tt> is greater than or equal
5686 to <tt>op2</tt>.</li>
5687
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5688 <li><tt>slt</tt>: interprets the operands as signed values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5689 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
5690
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5691 <li><tt>sle</tt>: interprets the operands as signed values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5692 <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]5693</ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5694
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5695<p>If the operands are <a href="#t_pointer">pointer</a> typed, the pointer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5696 values are compared as if they were integers.</p>
5697
5698<p>If the operands are integer vectors, then they are compared element by
5699 element. The result is an <tt>i1</tt> vector with the same number of elements
5700 as the values being compared. Otherwise, the result is an <tt>i1</tt>.</p>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5701
5702<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5703<pre>
5704 &lt;result&gt; = icmp eq i32 4, 5 <i>; yields: result=false</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5705 &lt;result&gt; = icmp ne float* %X, %X <i>; yields: result=false</i>
5706 &lt;result&gt; = icmp ult i16 4, 5 <i>; yields: result=true</i>
5707 &lt;result&gt; = icmp sgt i16 4, 5 <i>; yields: result=false</i>
5708 &lt;result&gt; = icmp ule i16 -4, 5 <i>; yields: result=false</i>
5709 &lt;result&gt; = icmp sge i16 4, 5 <i>; yields: result=false</i>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5710</pre>
Dan Gohmanc766f722009-01-22 01:39:38 +0000[diff] [blame]5711
5712<p>Note that the code generator does not yet support vector types with
5713 the <tt>icmp</tt> instruction.</p>
5714
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5715</div>
5716
5717<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5718<h4>
5719 <a name="i_fcmp">'<tt>fcmp</tt>' Instruction</a>
5720</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5721
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5722<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5723
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5724<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5725<pre>
5726 &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]5727</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5728
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5729<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5730<p>The '<tt>fcmp</tt>' instruction returns a boolean value or vector of boolean
5731 values based on comparison of its operands.</p>
5732
5733<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]5734(<a href="#t_integer"><tt>i1</tt></a>).</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5735
5736<p>If the operands are floating point vectors, then the result type is a vector
5737 of boolean with the same number of elements as the operands being
5738 compared.</p>
5739
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5740<h5>Arguments:</h5>
5741<p>The '<tt>fcmp</tt>' instruction takes three operands. The first operand is
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5742 the condition code indicating the kind of comparison to perform. It is not a
5743 value, just a keyword. The possible condition code are:</p>
5744
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5745<ol>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]5746 <li><tt>false</tt>: no comparison, always returns false</li>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5747 <li><tt>oeq</tt>: ordered and equal</li>
5748 <li><tt>ogt</tt>: ordered and greater than </li>
5749 <li><tt>oge</tt>: ordered and greater than or equal</li>
5750 <li><tt>olt</tt>: ordered and less than </li>
5751 <li><tt>ole</tt>: ordered and less than or equal</li>
5752 <li><tt>one</tt>: ordered and not equal</li>
5753 <li><tt>ord</tt>: ordered (no nans)</li>
5754 <li><tt>ueq</tt>: unordered or equal</li>
5755 <li><tt>ugt</tt>: unordered or greater than </li>
5756 <li><tt>uge</tt>: unordered or greater than or equal</li>
5757 <li><tt>ult</tt>: unordered or less than </li>
5758 <li><tt>ule</tt>: unordered or less than or equal</li>
5759 <li><tt>une</tt>: unordered or not equal</li>
5760 <li><tt>uno</tt>: unordered (either nans)</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]5761 <li><tt>true</tt>: no comparison, always returns true</li>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5762</ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5763
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5764<p><i>Ordered</i> means that neither operand is a QNAN while
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5765 <i>unordered</i> means that either operand may be a QNAN.</p>
5766
5767<p>Each of <tt>val1</tt> and <tt>val2</tt> arguments must be either
5768 a <a href="#t_floating">floating point</a> type or
5769 a <a href="#t_vector">vector</a> of floating point type. They must have
5770 identical types.</p>
5771
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5772<h5>Semantics:</h5>
Gabor Greiffb224a22008-08-07 21:46:00 +0000[diff] [blame]5773<p>The '<tt>fcmp</tt>' instruction compares <tt>op1</tt> and <tt>op2</tt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5774 according to the condition code given as <tt>cond</tt>. If the operands are
5775 vectors, then the vectors are compared element by element. Each comparison
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]5776 performed always yields an <a href="#t_integer">i1</a> result, as
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5777 follows:</p>
5778
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5779<ol>
5780 <li><tt>false</tt>: always yields <tt>false</tt>, regardless of operands.</li>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5781
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5782 <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]5783 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
5784
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]5785 <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]5786 <tt>op1</tt> is greater than <tt>op2</tt>.</li>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5787
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5788 <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]5789 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
5790
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5791 <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]5792 <tt>op1</tt> is less than <tt>op2</tt>.</li>
5793
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5794 <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]5795 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
5796
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5797 <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]5798 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
5799
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]5800 <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]5801
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5802 <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]5803 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
5804
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5805 <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]5806 <tt>op1</tt> is greater than <tt>op2</tt>.</li>
5807
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5808 <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]5809 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
5810
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5811 <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]5812 <tt>op1</tt> is less than <tt>op2</tt>.</li>
5813
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5814 <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]5815 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
5816
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5817 <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]5818 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
5819
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]5820 <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]5821
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5822 <li><tt>true</tt>: always yields <tt>true</tt>, regardless of operands.</li>
5823</ol>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5824
5825<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5826<pre>
5827 &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]5828 &lt;result&gt; = fcmp one float 4.0, 5.0 <i>; yields: result=true</i>
5829 &lt;result&gt; = fcmp olt float 4.0, 5.0 <i>; yields: result=true</i>
5830 &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]5831</pre>
Dan Gohmanc766f722009-01-22 01:39:38 +0000[diff] [blame]5832
5833<p>Note that the code generator does not yet support vector types with
5834 the <tt>fcmp</tt> instruction.</p>
5835
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5836</div>
5837
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5838<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5839<h4>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5840 <a name="i_phi">'<tt>phi</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5841</h4>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5842
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5843<div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5844
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5845<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5846<pre>
5847 &lt;result&gt; = phi &lt;ty&gt; [ &lt;val0&gt;, &lt;label0&gt;], ...
5848</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5849
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5850<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5851<p>The '<tt>phi</tt>' instruction is used to implement the &#966; node in the
5852 SSA graph representing the function.</p>
5853
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5854<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5855<p>The type of the incoming values is specified with the first type field. After
5856 this, the '<tt>phi</tt>' instruction takes a list of pairs as arguments, with
5857 one pair for each predecessor basic block of the current block. Only values
5858 of <a href="#t_firstclass">first class</a> type may be used as the value
5859 arguments to the PHI node. Only labels may be used as the label
5860 arguments.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5861
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5862<p>There must be no non-phi instructions between the start of a basic block and
5863 the PHI instructions: i.e. PHI instructions must be first in a basic
5864 block.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5865
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5866<p>For the purposes of the SSA form, the use of each incoming value is deemed to
5867 occur on the edge from the corresponding predecessor block to the current
5868 block (but after any definition of an '<tt>invoke</tt>' instruction's return
5869 value on the same edge).</p>
Jay Foadd2449092009-06-03 10:20:10 +0000[diff] [blame]5870
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5871<h5>Semantics:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5872<p>At runtime, the '<tt>phi</tt>' instruction logically takes on the value
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5873 specified by the pair corresponding to the predecessor basic block that
5874 executed just prior to the current block.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5875
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5876<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5877<pre>
5878Loop: ; Infinite loop that counts from 0 on up...
5879 %indvar = phi i32 [ 0, %LoopHeader ], [ %nextindvar, %Loop ]
5880 %nextindvar = add i32 %indvar, 1
5881 br label %Loop
5882</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5883
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5884</div>
5885
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5886<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5887<h4>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5888 <a name="i_select">'<tt>select</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5889</h4>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5890
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5891<div>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5892
5893<h5>Syntax:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5894<pre>
Dan Gohmanf72fb672008-09-09 01:02:47 +0000[diff] [blame]5895 &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>
5896
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]5897 <i>selty</i> is either i1 or {&lt;N x i1&gt;}
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5898</pre>
5899
5900<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5901<p>The '<tt>select</tt>' instruction is used to choose one value based on a
5902 condition, without branching.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5903
5904
5905<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5906<p>The '<tt>select</tt>' instruction requires an 'i1' value or a vector of 'i1'
5907 values indicating the condition, and two values of the
5908 same <a href="#t_firstclass">first class</a> type. If the val1/val2 are
5909 vectors and the condition is a scalar, then entire vectors are selected, not
5910 individual elements.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5911
5912<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5913<p>If the condition is an i1 and it evaluates to 1, the instruction returns the
5914 first value argument; otherwise, it returns the second value argument.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5915
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5916<p>If the condition is a vector of i1, then the value arguments must be vectors
5917 of the same size, and the selection is done element by element.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5918
5919<h5>Example:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5920<pre>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]5921 %X = select i1 true, i8 17, i8 42 <i>; yields i8:17</i>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5922</pre>
Dan Gohmanc766f722009-01-22 01:39:38 +0000[diff] [blame]5923
5924<p>Note that the code generator does not yet support conditions
5925 with vector type.</p>
5926
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5927</div>
5928
Robert Bocchino05ccd702006-01-15 20:48:27 +0000[diff] [blame]5929<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5930<h4>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5931 <a name="i_call">'<tt>call</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5932</h4>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5933
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5934<div>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5935
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]5936<h5>Syntax:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5937<pre>
Devang Patel307e8ab2008-10-07 17:48:33 +0000[diff] [blame]5938 &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]5939</pre>
5940
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]5941<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5942<p>The '<tt>call</tt>' instruction represents a simple function call.</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5943
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]5944<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5945<p>This instruction requires several arguments:</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5946
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]5947<ol>
Jeffrey Yasskin95fa80a2010-01-09 19:44:16 +0000[diff] [blame]5948 <li>The optional "tail" marker indicates that the callee function does not
5949 access any allocas or varargs in the caller. Note that calls may be
5950 marked "tail" even if they do not occur before
5951 a <a href="#i_ret"><tt>ret</tt></a> instruction. If the "tail" marker is
5952 present, the function call is eligible for tail call optimization,
5953 but <a href="CodeGenerator.html#tailcallopt">might not in fact be
Evan Chengdc444e92010-03-08 21:05:02 +0000[diff] [blame]5954 optimized into a jump</a>. The code generator may optimize calls marked
5955 "tail" with either 1) automatic <a href="CodeGenerator.html#sibcallopt">
5956 sibling call optimization</a> when the caller and callee have
5957 matching signatures, or 2) forced tail call optimization when the
5958 following extra requirements are met:
Jeffrey Yasskin95fa80a2010-01-09 19:44:16 +0000[diff] [blame]5959 <ul>
5960 <li>Caller and callee both have the calling
5961 convention <tt>fastcc</tt>.</li>
5962 <li>The call is in tail position (ret immediately follows call and ret
5963 uses value of call or is void).</li>
5964 <li>Option <tt>-tailcallopt</tt> is enabled,
Dan Gohmanfbbee8d2010-03-02 01:08:11 +0000[diff] [blame]5965 or <code>llvm::GuaranteedTailCallOpt</code> is <code>true</code>.</li>
Jeffrey Yasskin95fa80a2010-01-09 19:44:16 +0000[diff] [blame]5966 <li><a href="CodeGenerator.html#tailcallopt">Platform specific
5967 constraints are met.</a></li>
5968 </ul>
5969 </li>
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]5970
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5971 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
5972 convention</a> the call should use. If none is specified, the call
Jeffrey Yasskin95fa80a2010-01-09 19:44:16 +0000[diff] [blame]5973 defaults to using C calling conventions. The calling convention of the
5974 call must match the calling convention of the target function, or else the
5975 behavior is undefined.</li>
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]5976
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5977 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
5978 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
5979 '<tt>inreg</tt>' attributes are valid here.</li>
5980
5981 <li>'<tt>ty</tt>': the type of the call instruction itself which is also the
5982 type of the return value. Functions that return no value are marked
5983 <tt><a href="#t_void">void</a></tt>.</li>
5984
5985 <li>'<tt>fnty</tt>': shall be the signature of the pointer to function value
5986 being invoked. The argument types must match the types implied by this
5987 signature. This type can be omitted if the function is not varargs and if
5988 the function type does not return a pointer to a function.</li>
5989
5990 <li>'<tt>fnptrval</tt>': An LLVM value containing a pointer to a function to
5991 be invoked. In most cases, this is a direct function invocation, but
5992 indirect <tt>call</tt>s are just as possible, calling an arbitrary pointer
5993 to function value.</li>
5994
5995 <li>'<tt>function args</tt>': argument list whose types match the function
Chris Lattner0724fbd2010-03-02 06:36:51 +0000[diff] [blame]5996 signature argument types and parameter attributes. All arguments must be
5997 of <a href="#t_firstclass">first class</a> type. If the function
5998 signature indicates the function accepts a variable number of arguments,
5999 the extra arguments can be specified.</li>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6000
6001 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
6002 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
6003 '<tt>readnone</tt>' attributes are valid here.</li>
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]6004</ol>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]6005
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]6006<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6007<p>The '<tt>call</tt>' instruction is used to cause control flow to transfer to
6008 a specified function, with its incoming arguments bound to the specified
6009 values. Upon a '<tt><a href="#i_ret">ret</a></tt>' instruction in the called
6010 function, control flow continues with the instruction after the function
6011 call, and the return value of the function is bound to the result
6012 argument.</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]6013
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]6014<h5>Example:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]6015<pre>
Nick Lewyckydb7e3c92007-09-08 13:57:50 +0000[diff] [blame]6016 %retval = call i32 @test(i32 %argc)
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]6017 call i32 (i8*, ...)* @printf(i8* %msg, i32 12, i8 42) <i>; yields i32</i>
Chris Lattner772fccf2008-03-21 17:24:17 +0000[diff] [blame]6018 %X = tail call i32 @foo() <i>; yields i32</i>
6019 %Y = tail call <a href="#callingconv">fastcc</a> i32 @foo() <i>; yields i32</i>
6020 call void %foo(i8 97 signext)
Devang Patelc3fc6df2008-03-10 20:49:15 +0000[diff] [blame]6021
6022 %struct.A = type { i32, i8 }
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]6023 %r = call %struct.A @foo() <i>; yields { 32, i8 }</i>
Dan Gohmanb1e6b962008-10-04 19:00:07 +0000[diff] [blame]6024 %gr = extractvalue %struct.A %r, 0 <i>; yields i32</i>
6025 %gr1 = extractvalue %struct.A %r, 1 <i>; yields i8</i>
Chris Lattner85a350f2008-10-08 06:26:11 +0000[diff] [blame]6026 %Z = call void @foo() noreturn <i>; indicates that %foo never returns normally</i>
Matthijs Kooijmancb73d192008-10-07 10:03:45 +0000[diff] [blame]6027 %ZZ = call zeroext i32 @bar() <i>; Return value is %zero extended</i>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]6028</pre>
6029
Dale Johannesen07de8d12009-09-24 18:38:21 +0000[diff] [blame]6030<p>llvm treats calls to some functions with names and arguments that match the
Dale Johannesen9f8380b2009-09-25 17:04:42 +0000[diff] [blame]6031standard C99 library as being the C99 library functions, and may perform
6032optimizations or generate code for them under that assumption. This is
6033something we'd like to change in the future to provide better support for
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]6034freestanding environments and non-C-based languages.</p>
Dale Johannesen07de8d12009-09-24 18:38:21 +0000[diff] [blame]6035
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]6036</div>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]6037
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6038<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6039<h4>
Chris Lattnerfb6977d2006-01-13 23:26:01 +0000[diff] [blame]6040 <a name="i_va_arg">'<tt>va_arg</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6041</h4>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]6042
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6043<div>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]6044
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]6045<h5>Syntax:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]6046<pre>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]6047 &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]6048</pre>
6049
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]6050<h5>Overview:</h5>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]6051<p>The '<tt>va_arg</tt>' instruction is used to access arguments passed through
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6052 the "variable argument" area of a function call. It is used to implement the
6053 <tt>va_arg</tt> macro in C.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]6054
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]6055<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6056<p>This instruction takes a <tt>va_list*</tt> value and the type of the
6057 argument. It returns a value of the specified argument type and increments
6058 the <tt>va_list</tt> to point to the next argument. The actual type
6059 of <tt>va_list</tt> is target specific.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]6060
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]6061<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6062<p>The '<tt>va_arg</tt>' instruction loads an argument of the specified type
6063 from the specified <tt>va_list</tt> and causes the <tt>va_list</tt> to point
6064 to the next argument. For more information, see the variable argument
6065 handling <a href="#int_varargs">Intrinsic Functions</a>.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]6066
6067<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]6068 take a variable number of arguments, for example, the <tt>vfprintf</tt>
6069 function.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]6070
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6071<p><tt>va_arg</tt> is an LLVM instruction instead of
6072 an <a href="#intrinsics">intrinsic function</a> because it takes a type as an
6073 argument.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]6074
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]6075<h5>Example:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]6076<p>See the <a href="#int_varargs">variable argument processing</a> section.</p>
6077
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6078<p>Note that the code generator does not yet fully support va_arg on many
6079 targets. Also, it does not currently support va_arg with aggregate types on
6080 any target.</p>
Dan Gohmanf3e60bd2009-01-12 23:12:39 +0000[diff] [blame]6081
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]6082</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6083
Bill Wendlingf78faf82011-08-02 21:52:38 +0000[diff] [blame]6084<!-- _______________________________________________________________________ -->
6085<h4>
6086 <a name="i_landingpad">'<tt>landingpad</tt>' Instruction</a>
6087</h4>
6088
6089<div>
6090
6091<h5>Syntax:</h5>
6092<pre>
Bill Wendlingbf13ee12011-08-08 08:06:05 +0000[diff] [blame]6093 &lt;resultval&gt; = landingpad &lt;somety&gt; personality &lt;type&gt; &lt;pers_fn&gt; &lt;clause&gt;+
6094 &lt;resultval&gt; = landingpad &lt;somety&gt; personality &lt;type&gt; &lt;pers_fn&gt; cleanup &lt;clause&gt;*
6095
Bill Wendlingf78faf82011-08-02 21:52:38 +0000[diff] [blame]6096 &lt;clause&gt; := catch &lt;type&gt; &lt;value&gt;
Bill Wendlinge6e88262011-08-12 20:24:12 +0000[diff] [blame]6097 &lt;clause&gt; := filter &lt;array constant type&gt; &lt;array constant&gt;
Bill Wendlingf78faf82011-08-02 21:52:38 +0000[diff] [blame]6098</pre>
6099
6100<h5>Overview:</h5>
6101<p>The '<tt>landingpad</tt>' instruction is used by
6102 <a href="ExceptionHandling.html#overview">LLVM's exception handling
6103 system</a> to specify that a basic block is a landing pad &mdash; one where
6104 the exception lands, and corresponds to the code found in the
6105 <i><tt>catch</tt></i> portion of a <i><tt>try/catch</tt></i> sequence. It
6106 defines values supplied by the personality function (<tt>pers_fn</tt>) upon
6107 re-entry to the function. The <tt>resultval</tt> has the
6108 type <tt>somety</tt>.</p>
6109
6110<h5>Arguments:</h5>
6111<p>This instruction takes a <tt>pers_fn</tt> value. This is the personality
6112 function associated with the unwinding mechanism. The optional
6113 <tt>cleanup</tt> flag indicates that the landing pad block is a cleanup.</p>
6114
6115<p>A <tt>clause</tt> begins with the clause type &mdash; <tt>catch</tt>
Bill Wendlinge6e88262011-08-12 20:24:12 +0000[diff] [blame]6116 or <tt>filter</tt> &mdash; and contains the global variable representing the
6117 "type" that may be caught or filtered respectively. Unlike the
6118 <tt>catch</tt> clause, the <tt>filter</tt> clause takes an array constant as
6119 its argument. Use "<tt>[0 x i8**] undef</tt>" for a filter which cannot
6120 throw. The '<tt>landingpad</tt>' instruction must contain <em>at least</em>
Bill Wendlingf78faf82011-08-02 21:52:38 +0000[diff] [blame]6121 one <tt>clause</tt> or the <tt>cleanup</tt> flag.</p>
6122
6123<h5>Semantics:</h5>
6124<p>The '<tt>landingpad</tt>' instruction defines the values which are set by the
6125 personality function (<tt>pers_fn</tt>) upon re-entry to the function, and
6126 therefore the "result type" of the <tt>landingpad</tt> instruction. As with
6127 calling conventions, how the personality function results are represented in
6128 LLVM IR is target specific.</p>
6129
Bill Wendlingb7a01352011-08-03 17:17:06 +0000[diff] [blame]6130<p>The clauses are applied in order from top to bottom. If two
6131 <tt>landingpad</tt> instructions are merged together through inlining, the
Bill Wendling2905c322011-08-08 07:58:58 +0000[diff] [blame]6132 clauses from the calling function are appended to the list of clauses.</p>
Bill Wendlingb7a01352011-08-03 17:17:06 +0000[diff] [blame]6133
Bill Wendlingf78faf82011-08-02 21:52:38 +0000[diff] [blame]6134<p>The <tt>landingpad</tt> instruction has several restrictions:</p>
6135
6136<ul>
6137 <li>A landing pad block is a basic block which is the unwind destination of an
6138 '<tt>invoke</tt>' instruction.</li>
6139 <li>A landing pad block must have a '<tt>landingpad</tt>' instruction as its
6140 first non-PHI instruction.</li>
6141 <li>There can be only one '<tt>landingpad</tt>' instruction within the landing
6142 pad block.</li>
6143 <li>A basic block that is not a landing pad block may not include a
6144 '<tt>landingpad</tt>' instruction.</li>
6145 <li>All '<tt>landingpad</tt>' instructions in a function must have the same
6146 personality function.</li>
6147</ul>
6148
6149<h5>Example:</h5>
6150<pre>
6151 ;; A landing pad which can catch an integer.
6152 %res = landingpad { i8*, i32 } personality i32 (...)* @__gxx_personality_v0
6153 catch i8** @_ZTIi
6154 ;; A landing pad that is a cleanup.
6155 %res = landingpad { i8*, i32 } personality i32 (...)* @__gxx_personality_v0
Bill Wendlinge6e88262011-08-12 20:24:12 +0000[diff] [blame]6156 cleanup
Bill Wendlingf78faf82011-08-02 21:52:38 +0000[diff] [blame]6157 ;; A landing pad which can catch an integer and can only throw a double.
6158 %res = landingpad { i8*, i32 } personality i32 (...)* @__gxx_personality_v0
6159 catch i8** @_ZTIi
Bill Wendlinge6e88262011-08-12 20:24:12 +0000[diff] [blame]6160 filter [1 x i8**] [@_ZTId]
Bill Wendlingf78faf82011-08-02 21:52:38 +0000[diff] [blame]6161</pre>
6162
6163</div>
6164
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6165</div>
6166
6167</div>
6168
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6169<!-- *********************************************************************** -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6170<h2><a name="intrinsics">Intrinsic Functions</a></h2>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]6171<!-- *********************************************************************** -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6172
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6173<div>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6174
6175<p>LLVM supports the notion of an "intrinsic function". These functions have
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6176 well known names and semantics and are required to follow certain
6177 restrictions. Overall, these intrinsics represent an extension mechanism for
6178 the LLVM language that does not require changing all of the transformations
6179 in LLVM when adding to the language (or the bitcode reader/writer, the
6180 parser, etc...).</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6181
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]6182<p>Intrinsic function names must all start with an "<tt>llvm.</tt>" prefix. This
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6183 prefix is reserved in LLVM for intrinsic names; thus, function names may not
6184 begin with this prefix. Intrinsic functions must always be external
6185 functions: you cannot define the body of intrinsic functions. Intrinsic
6186 functions may only be used in call or invoke instructions: it is illegal to
6187 take the address of an intrinsic function. Additionally, because intrinsic
6188 functions are part of the LLVM language, it is required if any are added that
6189 they be documented here.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6190
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6191<p>Some intrinsic functions can be overloaded, i.e., the intrinsic represents a
6192 family of functions that perform the same operation but on different data
6193 types. Because LLVM can represent over 8 million different integer types,
6194 overloading is used commonly to allow an intrinsic function to operate on any
6195 integer type. One or more of the argument types or the result type can be
6196 overloaded to accept any integer type. Argument types may also be defined as
6197 exactly matching a previous argument's type or the result type. This allows
6198 an intrinsic function which accepts multiple arguments, but needs all of them
6199 to be of the same type, to only be overloaded with respect to a single
6200 argument or the result.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6201
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6202<p>Overloaded intrinsics will have the names of its overloaded argument types
6203 encoded into its function name, each preceded by a period. Only those types
6204 which are overloaded result in a name suffix. Arguments whose type is matched
6205 against another type do not. For example, the <tt>llvm.ctpop</tt> function
6206 can take an integer of any width and returns an integer of exactly the same
6207 integer width. This leads to a family of functions such as
6208 <tt>i8 @llvm.ctpop.i8(i8 %val)</tt> and <tt>i29 @llvm.ctpop.i29(i29
6209 %val)</tt>. Only one type, the return type, is overloaded, and only one type
6210 suffix is required. Because the argument's type is matched against the return
6211 type, it does not require its own name suffix.</p>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]6212
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]6213<p>To learn how to add an intrinsic function, please see the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6214 <a href="ExtendingLLVM.html">Extending LLVM Guide</a>.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6215
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6216<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6217<h3>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6218 <a name="int_varargs">Variable Argument Handling Intrinsics</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6219</h3>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6220
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6221<div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6222
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6223<p>Variable argument support is defined in LLVM with
6224 the <a href="#i_va_arg"><tt>va_arg</tt></a> instruction and these three
6225 intrinsic functions. These functions are related to the similarly named
6226 macros defined in the <tt>&lt;stdarg.h&gt;</tt> header file.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6227
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6228<p>All of these functions operate on arguments that use a target-specific value
6229 type "<tt>va_list</tt>". The LLVM assembly language reference manual does
6230 not define what this type is, so all transformations should be prepared to
6231 handle these functions regardless of the type used.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6232
Chris Lattner374ab302006-05-15 17:26:46 +0000[diff] [blame]6233<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]6234 instruction and the variable argument handling intrinsic functions are
6235 used.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6236
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]6237<pre class="doc_code">
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]6238define i32 @test(i32 %X, ...) {
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6239 ; Initialize variable argument processing
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]6240 %ap = alloca i8*
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]6241 %ap2 = bitcast i8** %ap to i8*
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]6242 call void @llvm.va_start(i8* %ap2)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6243
6244 ; Read a single integer argument
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]6245 %tmp = va_arg i8** %ap, i32
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6246
6247 ; Demonstrate usage of llvm.va_copy and llvm.va_end
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]6248 %aq = alloca i8*
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]6249 %aq2 = bitcast i8** %aq to i8*
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]6250 call void @llvm.va_copy(i8* %aq2, i8* %ap2)
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]6251 call void @llvm.va_end(i8* %aq2)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6252
6253 ; Stop processing of arguments.
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]6254 call void @llvm.va_end(i8* %ap2)
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]6255 ret i32 %tmp
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6256}
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]6257
6258declare void @llvm.va_start(i8*)
6259declare void @llvm.va_copy(i8*, i8*)
6260declare void @llvm.va_end(i8*)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6261</pre>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6262
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6263<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6264<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6265 <a name="int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6266</h4>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6267
6268
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6269<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6270
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6271<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6272<pre>
6273 declare void %llvm.va_start(i8* &lt;arglist&gt;)
6274</pre>
6275
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6276<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6277<p>The '<tt>llvm.va_start</tt>' intrinsic initializes <tt>*&lt;arglist&gt;</tt>
6278 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]6279
6280<h5>Arguments:</h5>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]6281<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]6282
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6283<h5>Semantics:</h5>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]6284<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]6285 macro available in C. In a target-dependent way, it initializes
6286 the <tt>va_list</tt> element to which the argument points, so that the next
6287 call to <tt>va_arg</tt> will produce the first variable argument passed to
6288 the function. Unlike the C <tt>va_start</tt> macro, this intrinsic does not
6289 need to know the last argument of the function as the compiler can figure
6290 that out.</p>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]6291
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]6292</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6293
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6294<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6295<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6296 <a name="int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6297</h4>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6298
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6299<div>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]6300
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6301<h5>Syntax:</h5>
6302<pre>
6303 declare void @llvm.va_end(i8* &lt;arglist&gt;)
6304</pre>
6305
6306<h5>Overview:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]6307<p>The '<tt>llvm.va_end</tt>' intrinsic destroys <tt>*&lt;arglist&gt;</tt>,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6308 which has been initialized previously
6309 with <tt><a href="#int_va_start">llvm.va_start</a></tt>
6310 or <tt><a href="#i_va_copy">llvm.va_copy</a></tt>.</p>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]6311
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6312<h5>Arguments:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]6313<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]6314
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6315<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]6316<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]6317 macro available in C. In a target-dependent way, it destroys
6318 the <tt>va_list</tt> element to which the argument points. Calls
6319 to <a href="#int_va_start"><tt>llvm.va_start</tt></a>
6320 and <a href="#int_va_copy"> <tt>llvm.va_copy</tt></a> must be matched exactly
6321 with calls to <tt>llvm.va_end</tt>.</p>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]6322
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]6323</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6324
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6325<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6326<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6327 <a name="int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6328</h4>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6329
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6330<div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6331
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6332<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6333<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]6334 declare void @llvm.va_copy(i8* &lt;destarglist&gt;, i8* &lt;srcarglist&gt;)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6335</pre>
6336
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6337<h5>Overview:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]6338<p>The '<tt>llvm.va_copy</tt>' intrinsic copies the current argument position
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6339 from the source argument list to the destination argument list.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6340
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6341<h5>Arguments:</h5>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]6342<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]6343 The second argument is a pointer to a <tt>va_list</tt> element to copy
6344 from.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6345
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6346<h5>Semantics:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]6347<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]6348 macro available in C. In a target-dependent way, it copies the
6349 source <tt>va_list</tt> element into the destination <tt>va_list</tt>
6350 element. This intrinsic is necessary because
6351 the <tt><a href="#int_va_start"> llvm.va_start</a></tt> intrinsic may be
6352 arbitrarily complex and require, for example, memory allocation.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6353
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]6354</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6355
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6356</div>
6357
Bill Wendling0246bb72011-07-31 06:45:03 +0000[diff] [blame]6358</div>
6359
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6360<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6361<h3>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6362 <a name="int_gc">Accurate Garbage Collection Intrinsics</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6363</h3>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6364
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6365<div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6366
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6367<p>LLVM support for <a href="GarbageCollection.html">Accurate Garbage
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]6368Collection</a> (GC) requires the implementation and generation of these
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6369intrinsics. These intrinsics allow identification of <a href="#int_gcroot">GC
6370roots on the stack</a>, as well as garbage collector implementations that
6371require <a href="#int_gcread">read</a> and <a href="#int_gcwrite">write</a>
6372barriers. Front-ends for type-safe garbage collected languages should generate
6373these intrinsics to make use of the LLVM garbage collectors. For more details,
6374see <a href="GarbageCollection.html">Accurate Garbage Collection with
6375LLVM</a>.</p>
Christopher Lamb303dae92007-12-17 01:00:21 +0000[diff] [blame]6376
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6377<p>The garbage collection intrinsics only operate on objects in the generic
6378 address space (address space zero).</p>
Christopher Lamb303dae92007-12-17 01:00:21 +0000[diff] [blame]6379
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6380<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6381<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6382 <a name="int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6383</h4>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6384
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6385<div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6386
6387<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6388<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]6389 declare void @llvm.gcroot(i8** %ptrloc, i8* %metadata)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6390</pre>
6391
6392<h5>Overview:</h5>
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]6393<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]6394 the code generator, and allows some metadata to be associated with it.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6395
6396<h5>Arguments:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6397<p>The first argument specifies the address of a stack object that contains the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6398 root pointer. The second pointer (which must be either a constant or a
6399 global value address) contains the meta-data to be associated with the
6400 root.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6401
6402<h5>Semantics:</h5>
Chris Lattner05d67092008-04-24 05:59:56 +0000[diff] [blame]6403<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]6404 location. At compile-time, the code generator generates information to allow
6405 the runtime to find the pointer at GC safe points. The '<tt>llvm.gcroot</tt>'
6406 intrinsic may only be used in a function which <a href="#gc">specifies a GC
6407 algorithm</a>.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6408
6409</div>
6410
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6411<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6412<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6413 <a name="int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6414</h4>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6415
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6416<div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6417
6418<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6419<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]6420 declare i8* @llvm.gcread(i8* %ObjPtr, i8** %Ptr)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6421</pre>
6422
6423<h5>Overview:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6424<p>The '<tt>llvm.gcread</tt>' intrinsic identifies reads of references from heap
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6425 locations, allowing garbage collector implementations that require read
6426 barriers.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6427
6428<h5>Arguments:</h5>
Chris Lattner80626e92006-03-14 20:02:51 +0000[diff] [blame]6429<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]6430 allocated from the garbage collector. The first object is a pointer to the
6431 start of the referenced object, if needed by the language runtime (otherwise
6432 null).</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6433
6434<h5>Semantics:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6435<p>The '<tt>llvm.gcread</tt>' intrinsic has the same semantics as a load
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6436 instruction, but may be replaced with substantially more complex code by the
6437 garbage collector runtime, as needed. The '<tt>llvm.gcread</tt>' intrinsic
6438 may only be used in a function which <a href="#gc">specifies a GC
6439 algorithm</a>.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6440
6441</div>
6442
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6443<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6444<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6445 <a name="int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6446</h4>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6447
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6448<div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6449
6450<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6451<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]6452 declare void @llvm.gcwrite(i8* %P1, i8* %Obj, i8** %P2)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6453</pre>
6454
6455<h5>Overview:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6456<p>The '<tt>llvm.gcwrite</tt>' intrinsic identifies writes of references to heap
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6457 locations, allowing garbage collector implementations that require write
6458 barriers (such as generational or reference counting collectors).</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6459
6460<h5>Arguments:</h5>
Chris Lattner80626e92006-03-14 20:02:51 +0000[diff] [blame]6461<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]6462 object to store it to, and the third is the address of the field of Obj to
6463 store to. If the runtime does not require a pointer to the object, Obj may
6464 be null.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6465
6466<h5>Semantics:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6467<p>The '<tt>llvm.gcwrite</tt>' intrinsic has the same semantics as a store
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6468 instruction, but may be replaced with substantially more complex code by the
6469 garbage collector runtime, as needed. The '<tt>llvm.gcwrite</tt>' intrinsic
6470 may only be used in a function which <a href="#gc">specifies a GC
6471 algorithm</a>.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6472
6473</div>
6474
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6475</div>
6476
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6477<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6478<h3>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6479 <a name="int_codegen">Code Generator Intrinsics</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6480</h3>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6481
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6482<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6483
6484<p>These intrinsics are provided by LLVM to expose special features that may
6485 only be implemented with code generator support.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6486
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6487<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6488<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6489 <a name="int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6490</h4>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6491
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6492<div>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6493
6494<h5>Syntax:</h5>
6495<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]6496 declare i8 *@llvm.returnaddress(i32 &lt;level&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6497</pre>
6498
6499<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6500<p>The '<tt>llvm.returnaddress</tt>' intrinsic attempts to compute a
6501 target-specific value indicating the return address of the current function
6502 or one of its callers.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6503
6504<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6505<p>The argument to this intrinsic indicates which function to return the address
6506 for. Zero indicates the calling function, one indicates its caller, etc.
6507 The argument is <b>required</b> to be a constant integer value.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6508
6509<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6510<p>The '<tt>llvm.returnaddress</tt>' intrinsic either returns a pointer
6511 indicating the return address of the specified call frame, or zero if it
6512 cannot be identified. The value returned by this intrinsic is likely to be
6513 incorrect or 0 for arguments other than zero, so it should only be used for
6514 debugging purposes.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6515
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6516<p>Note that calling this intrinsic does not prevent function inlining or other
6517 aggressive transformations, so the value returned may not be that of the
6518 obvious source-language caller.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6519
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6520</div>
6521
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6522<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6523<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6524 <a name="int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6525</h4>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6526
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6527<div>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6528
6529<h5>Syntax:</h5>
6530<pre>
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]6531 declare i8* @llvm.frameaddress(i32 &lt;level&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6532</pre>
6533
6534<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6535<p>The '<tt>llvm.frameaddress</tt>' intrinsic attempts to return the
6536 target-specific frame pointer value for the specified stack frame.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6537
6538<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6539<p>The argument to this intrinsic indicates which function to return the frame
6540 pointer for. Zero indicates the calling function, one indicates its caller,
6541 etc. The argument is <b>required</b> to be a constant integer value.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6542
6543<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6544<p>The '<tt>llvm.frameaddress</tt>' intrinsic either returns a pointer
6545 indicating the frame address of the specified call frame, or zero if it
6546 cannot be identified. The value returned by this intrinsic is likely to be
6547 incorrect or 0 for arguments other than zero, so it should only be used for
6548 debugging purposes.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6549
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6550<p>Note that calling this intrinsic does not prevent function inlining or other
6551 aggressive transformations, so the value returned may not be that of the
6552 obvious source-language caller.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6553
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6554</div>
6555
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]6556<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6557<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6558 <a name="int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6559</h4>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]6560
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6561<div>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]6562
6563<h5>Syntax:</h5>
6564<pre>
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]6565 declare i8* @llvm.stacksave()
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]6566</pre>
6567
6568<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6569<p>The '<tt>llvm.stacksave</tt>' intrinsic is used to remember the current state
6570 of the function stack, for use
6571 with <a href="#int_stackrestore"> <tt>llvm.stackrestore</tt></a>. This is
6572 useful for implementing language features like scoped automatic variable
6573 sized arrays in C99.</p>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]6574
6575<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6576<p>This intrinsic returns a opaque pointer value that can be passed
6577 to <a href="#int_stackrestore"><tt>llvm.stackrestore</tt></a>. When
6578 an <tt>llvm.stackrestore</tt> intrinsic is executed with a value saved
6579 from <tt>llvm.stacksave</tt>, it effectively restores the state of the stack
6580 to the state it was in when the <tt>llvm.stacksave</tt> intrinsic executed.
6581 In practice, this pops any <a href="#i_alloca">alloca</a> blocks from the
6582 stack that were allocated after the <tt>llvm.stacksave</tt> was executed.</p>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]6583
6584</div>
6585
6586<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6587<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6588 <a name="int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6589</h4>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]6590
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6591<div>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]6592
6593<h5>Syntax:</h5>
6594<pre>
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]6595 declare void @llvm.stackrestore(i8* %ptr)
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]6596</pre>
6597
6598<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6599<p>The '<tt>llvm.stackrestore</tt>' intrinsic is used to restore the state of
6600 the function stack to the state it was in when the
6601 corresponding <a href="#int_stacksave"><tt>llvm.stacksave</tt></a> intrinsic
6602 executed. This is useful for implementing language features like scoped
6603 automatic variable sized arrays in C99.</p>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]6604
6605<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6606<p>See the description
6607 for <a href="#int_stacksave"><tt>llvm.stacksave</tt></a>.</p>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]6608
6609</div>
6610
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]6611<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6612<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6613 <a name="int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6614</h4>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]6615
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6616<div>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]6617
6618<h5>Syntax:</h5>
6619<pre>
Bruno Cardoso Lopes9a767332011-06-14 04:58:37 +0000[diff] [blame]6620 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]6621</pre>
6622
6623<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6624<p>The '<tt>llvm.prefetch</tt>' intrinsic is a hint to the code generator to
6625 insert a prefetch instruction if supported; otherwise, it is a noop.
6626 Prefetches have no effect on the behavior of the program but can change its
6627 performance characteristics.</p>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]6628
6629<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6630<p><tt>address</tt> is the address to be prefetched, <tt>rw</tt> is the
6631 specifier determining if the fetch should be for a read (0) or write (1),
6632 and <tt>locality</tt> is a temporal locality specifier ranging from (0) - no
Bruno Cardoso Lopes9a767332011-06-14 04:58:37 +0000[diff] [blame]6633 locality, to (3) - extremely local keep in cache. The <tt>cache type</tt>
6634 specifies whether the prefetch is performed on the data (1) or instruction (0)
6635 cache. The <tt>rw</tt>, <tt>locality</tt> and <tt>cache type</tt> arguments
6636 must be constant integers.</p>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]6637
6638<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6639<p>This intrinsic does not modify the behavior of the program. In particular,
6640 prefetches cannot trap and do not produce a value. On targets that support
6641 this intrinsic, the prefetch can provide hints to the processor cache for
6642 better performance.</p>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]6643
6644</div>
6645
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]6646<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6647<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6648 <a name="int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6649</h4>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]6650
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6651<div>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]6652
6653<h5>Syntax:</h5>
6654<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]6655 declare void @llvm.pcmarker(i32 &lt;id&gt;)
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]6656</pre>
6657
6658<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6659<p>The '<tt>llvm.pcmarker</tt>' intrinsic is a method to export a Program
6660 Counter (PC) in a region of code to simulators and other tools. The method
6661 is target specific, but it is expected that the marker will use exported
6662 symbols to transmit the PC of the marker. The marker makes no guarantees
6663 that it will remain with any specific instruction after optimizations. It is
6664 possible that the presence of a marker will inhibit optimizations. The
6665 intended use is to be inserted after optimizations to allow correlations of
6666 simulation runs.</p>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]6667
6668<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6669<p><tt>id</tt> is a numerical id identifying the marker.</p>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]6670
6671<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6672<p>This intrinsic does not modify the behavior of the program. Backends that do
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]6673 not support this intrinsic may ignore it.</p>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]6674
6675</div>
6676
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]6677<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6678<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6679 <a name="int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6680</h4>
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]6681
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6682<div>
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]6683
6684<h5>Syntax:</h5>
6685<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]6686 declare i64 @llvm.readcyclecounter()
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]6687</pre>
6688
6689<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6690<p>The '<tt>llvm.readcyclecounter</tt>' intrinsic provides access to the cycle
6691 counter register (or similar low latency, high accuracy clocks) on those
6692 targets that support it. On X86, it should map to RDTSC. On Alpha, it
6693 should map to RPCC. As the backing counters overflow quickly (on the order
6694 of 9 seconds on alpha), this should only be used for small timings.</p>
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]6695
6696<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6697<p>When directly supported, reading the cycle counter should not modify any
6698 memory. Implementations are allowed to either return a application specific
6699 value or a system wide value. On backends without support, this is lowered
6700 to a constant 0.</p>
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]6701
6702</div>
6703
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6704</div>
6705
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6706<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6707<h3>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6708 <a name="int_libc">Standard C Library Intrinsics</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6709</h3>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6710
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6711<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6712
6713<p>LLVM provides intrinsics for a few important standard C library functions.
6714 These intrinsics allow source-language front-ends to pass information about
6715 the alignment of the pointer arguments to the code generator, providing
6716 opportunity for more efficient code generation.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6717
Chris Lattner33aec9e2004-02-12 17:01:32 +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_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6721</h4>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6722
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6723<div>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6724
6725<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6726<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]6727 integer bit width and for different address spaces. Not all targets support
6728 all bit widths however.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6729
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6730<pre>
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]6731 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]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.memcpy.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 Lattner33aec9e2004-02-12 17:01:32 +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.memcpy.*</tt>' intrinsics copy a block of memory from the
6739 source location to the destination location.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6740
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6741<p>Note that, unlike the standard libc function, the <tt>llvm.memcpy.*</tt>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6742 intrinsics do not return a value, takes extra alignment/isvolatile arguments
6743 and the pointers can be in specified address spaces.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6744
6745<h5>Arguments:</h5>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6746
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6747<p>The first argument is a pointer to the destination, the second is a pointer
6748 to the source. The third argument is an integer argument specifying the
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6749 number of bytes to copy, the fourth argument is the alignment of the
6750 source and destination locations, and the fifth is a boolean indicating a
6751 volatile access.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6752
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]6753<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]6754 then the caller guarantees that both the source and destination pointers are
6755 aligned to that boundary.</p>
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]6756
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]6757<p>If the <tt>isvolatile</tt> parameter is <tt>true</tt>, the
6758 <tt>llvm.memcpy</tt> call is a <a href="#volatile">volatile operation</a>.
6759 The detailed access behavior is not very cleanly specified and it is unwise
6760 to depend on it.</p>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6761
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6762<h5>Semantics:</h5>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6763
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6764<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
6765 source location to the destination location, which are not allowed to
6766 overlap. It copies "len" bytes of memory over. If the argument is known to
6767 be aligned to some boundary, this can be specified as the fourth argument,
6768 otherwise it should be set to 0 or 1.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6769
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6770</div>
6771
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6772<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6773<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6774 <a name="int_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6775</h4>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6776
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6777<div>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6778
6779<h5>Syntax:</h5>
Chris Lattner824b9582008-11-21 16:42:48 +0000[diff] [blame]6780<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]6781 width and for different address space. Not all targets support all bit
6782 widths however.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6783
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6784<pre>
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]6785 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]6786 i32 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]6787 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]6788 i64 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6789</pre>
6790
6791<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6792<p>The '<tt>llvm.memmove.*</tt>' intrinsics move a block of memory from the
6793 source location to the destination location. It is similar to the
6794 '<tt>llvm.memcpy</tt>' intrinsic but allows the two memory locations to
6795 overlap.</p>
Chris Lattner0eb51b42004-02-12 18:10:10 +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.memmove.*</tt>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6798 intrinsics do not return a value, takes extra alignment/isvolatile arguments
6799 and the pointers can be in specified address spaces.</p>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6800
6801<h5>Arguments:</h5>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6802
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6803<p>The first argument is a pointer to the destination, the second is a pointer
6804 to the source. The third argument is an integer argument specifying the
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6805 number of bytes to copy, the fourth argument is the alignment of the
6806 source and destination locations, and the fifth is a boolean indicating a
6807 volatile access.</p>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6808
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]6809<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]6810 then the caller guarantees that the source and destination pointers are
6811 aligned to that boundary.</p>
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]6812
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]6813<p>If the <tt>isvolatile</tt> parameter is <tt>true</tt>, the
6814 <tt>llvm.memmove</tt> call is a <a href="#volatile">volatile operation</a>.
6815 The detailed access behavior is not very cleanly specified and it is unwise
6816 to depend on it.</p>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6817
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6818<h5>Semantics:</h5>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6819
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6820<p>The '<tt>llvm.memmove.*</tt>' intrinsics copy a block of memory from the
6821 source location to the destination location, which may overlap. It copies
6822 "len" bytes of memory over. If the argument is known to be aligned to some
6823 boundary, this can be specified as the fourth argument, otherwise it should
6824 be set to 0 or 1.</p>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6825
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6826</div>
6827
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6828<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6829<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6830 <a name="int_memset">'<tt>llvm.memset.*</tt>' Intrinsics</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6831</h4>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6832
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6833<div>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6834
6835<h5>Syntax:</h5>
Chris Lattner824b9582008-11-21 16:42:48 +0000[diff] [blame]6836<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]6837 width and for different address spaces. However, not all targets support all
6838 bit widths.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6839
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6840<pre>
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]6841 declare void @llvm.memset.p0i8.i32(i8* &lt;dest&gt;, i8 &lt;val&gt;,
Chris Lattnerff35c3f2010-04-08 00:54:34 +0000[diff] [blame]6842 i32 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]6843 declare void @llvm.memset.p0i8.i64(i8* &lt;dest&gt;, i8 &lt;val&gt;,
Chris Lattnerff35c3f2010-04-08 00:54:34 +0000[diff] [blame]6844 i64 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6845</pre>
6846
6847<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6848<p>The '<tt>llvm.memset.*</tt>' intrinsics fill a block of memory with a
6849 particular byte value.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6850
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6851<p>Note that, unlike the standard libc function, the <tt>llvm.memset</tt>
John Criswellcdcbbfc2010-07-30 16:30:28 +0000[diff] [blame]6852 intrinsic does not return a value and takes extra alignment/volatile
6853 arguments. Also, the destination can be in an arbitrary address space.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6854
6855<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6856<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]6857 byte value with which to fill it, the third argument is an integer argument
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6858 specifying the number of bytes to fill, and the fourth argument is the known
John Criswellcdcbbfc2010-07-30 16:30:28 +0000[diff] [blame]6859 alignment of the destination location.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6860
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]6861<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]6862 then the caller guarantees that the destination pointer is aligned to that
6863 boundary.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6864
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]6865<p>If the <tt>isvolatile</tt> parameter is <tt>true</tt>, the
6866 <tt>llvm.memset</tt> call is a <a href="#volatile">volatile operation</a>.
6867 The detailed access behavior is not very cleanly specified and it is unwise
6868 to depend on it.</p>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6869
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6870<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6871<p>The '<tt>llvm.memset.*</tt>' intrinsics fill "len" bytes of memory starting
6872 at the destination location. If the argument is known to be aligned to some
6873 boundary, this can be specified as the fourth argument, otherwise it should
6874 be set to 0 or 1.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6875
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6876</div>
6877
Chris Lattner32006282004-06-11 02:28:03 +0000[diff] [blame]6878<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6879<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6880 <a name="int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6881</h4>
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]6882
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6883<div>
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]6884
6885<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6886<p>This is an overloaded intrinsic. You can use <tt>llvm.sqrt</tt> on any
6887 floating point or vector of floating point type. Not all targets support all
6888 types however.</p>
6889
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]6890<pre>
Dale Johannesen408f9c12007-10-02 17:47:38 +0000[diff] [blame]6891 declare float @llvm.sqrt.f32(float %Val)
6892 declare double @llvm.sqrt.f64(double %Val)
6893 declare x86_fp80 @llvm.sqrt.f80(x86_fp80 %Val)
6894 declare fp128 @llvm.sqrt.f128(fp128 %Val)
6895 declare ppc_fp128 @llvm.sqrt.ppcf128(ppc_fp128 %Val)
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]6896</pre>
6897
6898<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6899<p>The '<tt>llvm.sqrt</tt>' intrinsics return the sqrt of the specified operand,
6900 returning the same value as the libm '<tt>sqrt</tt>' functions would.
6901 Unlike <tt>sqrt</tt> in libm, however, <tt>llvm.sqrt</tt> has undefined
6902 behavior for negative numbers other than -0.0 (which allows for better
6903 optimization, because there is no need to worry about errno being
6904 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]6905
6906<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6907<p>The argument and return value are floating point numbers of the same
6908 type.</p>
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]6909
6910<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6911<p>This function returns the sqrt of the specified operand if it is a
6912 nonnegative floating point number.</p>
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]6913
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]6914</div>
6915
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6916<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6917<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6918 <a name="int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6919</h4>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6920
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6921<div>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6922
6923<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6924<p>This is an overloaded intrinsic. You can use <tt>llvm.powi</tt> on any
6925 floating point or vector of floating point type. Not all targets support all
6926 types however.</p>
6927
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6928<pre>
Dale Johannesen408f9c12007-10-02 17:47:38 +0000[diff] [blame]6929 declare float @llvm.powi.f32(float %Val, i32 %power)
6930 declare double @llvm.powi.f64(double %Val, i32 %power)
6931 declare x86_fp80 @llvm.powi.f80(x86_fp80 %Val, i32 %power)
6932 declare fp128 @llvm.powi.f128(fp128 %Val, i32 %power)
6933 declare ppc_fp128 @llvm.powi.ppcf128(ppc_fp128 %Val, i32 %power)
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6934</pre>
6935
6936<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6937<p>The '<tt>llvm.powi.*</tt>' intrinsics return the first operand raised to the
6938 specified (positive or negative) power. The order of evaluation of
6939 multiplications is not defined. When a vector of floating point type is
6940 used, the second argument remains a scalar integer value.</p>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6941
6942<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6943<p>The second argument is an integer power, and the first is a value to raise to
6944 that power.</p>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6945
6946<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6947<p>This function returns the first value raised to the second power with an
6948 unspecified sequence of rounding operations.</p>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6949
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6950</div>
6951
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6952<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6953<h4>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6954 <a name="int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6955</h4>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6956
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6957<div>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6958
6959<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6960<p>This is an overloaded intrinsic. You can use <tt>llvm.sin</tt> on any
6961 floating point or vector of floating point type. Not all targets support all
6962 types however.</p>
6963
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6964<pre>
6965 declare float @llvm.sin.f32(float %Val)
6966 declare double @llvm.sin.f64(double %Val)
6967 declare x86_fp80 @llvm.sin.f80(x86_fp80 %Val)
6968 declare fp128 @llvm.sin.f128(fp128 %Val)
6969 declare ppc_fp128 @llvm.sin.ppcf128(ppc_fp128 %Val)
6970</pre>
6971
6972<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6973<p>The '<tt>llvm.sin.*</tt>' intrinsics return the sine of the operand.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6974
6975<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6976<p>The argument and return value are floating point numbers of the same
6977 type.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6978
6979<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6980<p>This function returns the sine of the specified operand, returning the same
6981 values as the libm <tt>sin</tt> functions would, and handles error conditions
6982 in the same way.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6983
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6984</div>
6985
6986<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6987<h4>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6988 <a name="int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6989</h4>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6990
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6991<div>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6992
6993<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6994<p>This is an overloaded intrinsic. You can use <tt>llvm.cos</tt> on any
6995 floating point or vector of floating point type. Not all targets support all
6996 types however.</p>
6997
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6998<pre>
6999 declare float @llvm.cos.f32(float %Val)
7000 declare double @llvm.cos.f64(double %Val)
7001 declare x86_fp80 @llvm.cos.f80(x86_fp80 %Val)
7002 declare fp128 @llvm.cos.f128(fp128 %Val)
7003 declare ppc_fp128 @llvm.cos.ppcf128(ppc_fp128 %Val)
7004</pre>
7005
7006<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7007<p>The '<tt>llvm.cos.*</tt>' intrinsics return the cosine of the operand.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7008
7009<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7010<p>The argument and return value are floating point numbers of the same
7011 type.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7012
7013<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7014<p>This function returns the cosine of the specified operand, returning the same
7015 values as the libm <tt>cos</tt> functions would, and handles error conditions
7016 in the same way.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7017
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7018</div>
7019
7020<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7021<h4>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7022 <a name="int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7023</h4>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7024
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7025<div>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7026
7027<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7028<p>This is an overloaded intrinsic. You can use <tt>llvm.pow</tt> on any
7029 floating point or vector of floating point type. Not all targets support all
7030 types however.</p>
7031
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7032<pre>
7033 declare float @llvm.pow.f32(float %Val, float %Power)
7034 declare double @llvm.pow.f64(double %Val, double %Power)
7035 declare x86_fp80 @llvm.pow.f80(x86_fp80 %Val, x86_fp80 %Power)
7036 declare fp128 @llvm.pow.f128(fp128 %Val, fp128 %Power)
7037 declare ppc_fp128 @llvm.pow.ppcf128(ppc_fp128 %Val, ppc_fp128 Power)
7038</pre>
7039
7040<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7041<p>The '<tt>llvm.pow.*</tt>' intrinsics return the first operand raised to the
7042 specified (positive or negative) power.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7043
7044<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7045<p>The second argument is a floating point power, and the first is a value to
7046 raise to that power.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7047
7048<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7049<p>This function returns the first value raised to the second power, returning
7050 the same values as the libm <tt>pow</tt> functions would, and handles error
7051 conditions in the same way.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7052
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7053</div>
7054
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7055</div>
7056
Dan Gohman4e9011c2011-05-23 21:13:03 +0000[diff] [blame]7057<!-- _______________________________________________________________________ -->
7058<h4>
7059 <a name="int_exp">'<tt>llvm.exp.*</tt>' Intrinsic</a>
7060</h4>
7061
7062<div>
7063
7064<h5>Syntax:</h5>
7065<p>This is an overloaded intrinsic. You can use <tt>llvm.exp</tt> on any
7066 floating point or vector of floating point type. Not all targets support all
7067 types however.</p>
7068
7069<pre>
7070 declare float @llvm.exp.f32(float %Val)
7071 declare double @llvm.exp.f64(double %Val)
7072 declare x86_fp80 @llvm.exp.f80(x86_fp80 %Val)
7073 declare fp128 @llvm.exp.f128(fp128 %Val)
7074 declare ppc_fp128 @llvm.exp.ppcf128(ppc_fp128 %Val)
7075</pre>
7076
7077<h5>Overview:</h5>
7078<p>The '<tt>llvm.exp.*</tt>' intrinsics perform the exp function.</p>
7079
7080<h5>Arguments:</h5>
7081<p>The argument and return value are floating point numbers of the same
7082 type.</p>
7083
7084<h5>Semantics:</h5>
7085<p>This function returns the same values as the libm <tt>exp</tt> functions
7086 would, and handles error conditions in the same way.</p>
7087
7088</div>
7089
7090<!-- _______________________________________________________________________ -->
7091<h4>
7092 <a name="int_log">'<tt>llvm.log.*</tt>' Intrinsic</a>
7093</h4>
7094
7095<div>
7096
7097<h5>Syntax:</h5>
7098<p>This is an overloaded intrinsic. You can use <tt>llvm.log</tt> on any
7099 floating point or vector of floating point type. Not all targets support all
7100 types however.</p>
7101
7102<pre>
7103 declare float @llvm.log.f32(float %Val)
7104 declare double @llvm.log.f64(double %Val)
7105 declare x86_fp80 @llvm.log.f80(x86_fp80 %Val)
7106 declare fp128 @llvm.log.f128(fp128 %Val)
7107 declare ppc_fp128 @llvm.log.ppcf128(ppc_fp128 %Val)
7108</pre>
7109
7110<h5>Overview:</h5>
7111<p>The '<tt>llvm.log.*</tt>' intrinsics perform the log function.</p>
7112
7113<h5>Arguments:</h5>
7114<p>The argument and return value are floating point numbers of the same
7115 type.</p>
7116
7117<h5>Semantics:</h5>
7118<p>This function returns the same values as the libm <tt>log</tt> functions
7119 would, and handles error conditions in the same way.</p>
7120
Cameron Zwarich33390842011-07-08 21:39:21 +0000[diff] [blame]7121<h4>
7122 <a name="int_fma">'<tt>llvm.fma.*</tt>' Intrinsic</a>
7123</h4>
7124
7125<div>
7126
7127<h5>Syntax:</h5>
7128<p>This is an overloaded intrinsic. You can use <tt>llvm.fma</tt> on any
7129 floating point or vector of floating point type. Not all targets support all
7130 types however.</p>
7131
7132<pre>
7133 declare float @llvm.fma.f32(float %a, float %b, float %c)
7134 declare double @llvm.fma.f64(double %a, double %b, double %c)
7135 declare x86_fp80 @llvm.fma.f80(x86_fp80 %a, x86_fp80 %b, x86_fp80 %c)
7136 declare fp128 @llvm.fma.f128(fp128 %a, fp128 %b, fp128 %c)
7137 declare ppc_fp128 @llvm.fma.ppcf128(ppc_fp128 %a, ppc_fp128 %b, ppc_fp128 %c)
7138</pre>
7139
7140<h5>Overview:</h5>
Cameron Zwarichabc43e62011-07-08 22:13:55 +0000[diff] [blame]7141<p>The '<tt>llvm.fma.*</tt>' intrinsics perform the fused multiply-add
Cameron Zwarich33390842011-07-08 21:39:21 +0000[diff] [blame]7142 operation.</p>
7143
7144<h5>Arguments:</h5>
7145<p>The argument and return value are floating point numbers of the same
7146 type.</p>
7147
7148<h5>Semantics:</h5>
7149<p>This function returns the same values as the libm <tt>fma</tt> functions
7150 would.</p>
7151
Dan Gohman4e9011c2011-05-23 21:13:03 +0000[diff] [blame]7152</div>
7153
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7154<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7155<h3>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]7156 <a name="int_manip">Bit Manipulation Intrinsics</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7157</h3>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7158
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7159<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7160
7161<p>LLVM provides intrinsics for a few important bit manipulation operations.
7162 These allow efficient code generation for some algorithms.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7163
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7164<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7165<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]7166 <a name="int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7167</h4>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]7168
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7169<div>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]7170
7171<h5>Syntax:</h5>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]7172<p>This is an overloaded intrinsic function. You can use bswap on any integer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7173 type that is an even number of bytes (i.e. BitWidth % 16 == 0).</p>
7174
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]7175<pre>
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]7176 declare i16 @llvm.bswap.i16(i16 &lt;id&gt;)
7177 declare i32 @llvm.bswap.i32(i32 &lt;id&gt;)
7178 declare i64 @llvm.bswap.i64(i64 &lt;id&gt;)
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]7179</pre>
7180
7181<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7182<p>The '<tt>llvm.bswap</tt>' family of intrinsics is used to byte swap integer
7183 values with an even number of bytes (positive multiple of 16 bits). These
7184 are useful for performing operations on data that is not in the target's
7185 native byte order.</p>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]7186
7187<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7188<p>The <tt>llvm.bswap.i16</tt> intrinsic returns an i16 value that has the high
7189 and low byte of the input i16 swapped. Similarly,
7190 the <tt>llvm.bswap.i32</tt> intrinsic returns an i32 value that has the four
7191 bytes of the input i32 swapped, so that if the input bytes are numbered 0, 1,
7192 2, 3 then the returned i32 will have its bytes in 3, 2, 1, 0 order.
7193 The <tt>llvm.bswap.i48</tt>, <tt>llvm.bswap.i64</tt> and other intrinsics
7194 extend this concept to additional even-byte lengths (6 bytes, 8 bytes and
7195 more, respectively).</p>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]7196
7197</div>
7198
7199<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7200<h4>
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]7201 <a name="int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7202</h4>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7203
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7204<div>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7205
7206<h5>Syntax:</h5>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]7207<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]7208 width, or on any vector with integer elements. Not all targets support all
7209 bit widths or vector types, however.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7210
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7211<pre>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7212 declare i8 @llvm.ctpop.i8(i8 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]7213 declare i16 @llvm.ctpop.i16(i16 &lt;src&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]7214 declare i32 @llvm.ctpop.i32(i32 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]7215 declare i64 @llvm.ctpop.i64(i64 &lt;src&gt;)
7216 declare i256 @llvm.ctpop.i256(i256 &lt;src&gt;)
Owen Andersonf1ac4652011-07-01 21:52:38 +0000[diff] [blame]7217 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]7218</pre>
7219
7220<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7221<p>The '<tt>llvm.ctpop</tt>' family of intrinsics counts the number of bits set
7222 in a value.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7223
7224<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7225<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]7226 integer type, or a vector with integer elements.
7227 The return type must match the argument type.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7228
7229<h5>Semantics:</h5>
Owen Andersonf1ac4652011-07-01 21:52:38 +0000[diff] [blame]7230<p>The '<tt>llvm.ctpop</tt>' intrinsic counts the 1's in a variable, or within each
7231 element of a vector.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7232
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7233</div>
7234
7235<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7236<h4>
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]7237 <a name="int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7238</h4>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7239
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7240<div>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7241
7242<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7243<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]7244 integer bit width, or any vector whose elements are integers. Not all
7245 targets support all bit widths or vector types, however.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7246
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7247<pre>
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]7248 declare i8 @llvm.ctlz.i8 (i8 &lt;src&gt;)
7249 declare i16 @llvm.ctlz.i16(i16 &lt;src&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]7250 declare i32 @llvm.ctlz.i32(i32 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]7251 declare i64 @llvm.ctlz.i64(i64 &lt;src&gt;)
7252 declare i256 @llvm.ctlz.i256(i256 &lt;src&gt;)
Owen Andersonf1ac4652011-07-01 21:52:38 +0000[diff] [blame]7253 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]7254</pre>
7255
7256<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7257<p>The '<tt>llvm.ctlz</tt>' family of intrinsic functions counts the number of
7258 leading zeros in a variable.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7259
7260<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7261<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]7262 integer type, or any vector type with integer element type.
7263 The return type must match the argument type.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7264
7265<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7266<p>The '<tt>llvm.ctlz</tt>' intrinsic counts the leading (most significant)
Owen Andersonf1ac4652011-07-01 21:52:38 +0000[diff] [blame]7267 zeros in a variable, or within each element of the vector if the operation
7268 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]7269 the type of src. For example, <tt>llvm.ctlz(i32 2) = 30</tt>.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7270
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7271</div>
Chris Lattner32006282004-06-11 02:28:03 +0000[diff] [blame]7272
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]7273<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7274<h4>
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]7275 <a name="int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7276</h4>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]7277
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7278<div>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]7279
7280<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7281<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]7282 integer bit width, or any vector of integer elements. Not all targets
7283 support all bit widths or vector types, however.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7284
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]7285<pre>
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]7286 declare i8 @llvm.cttz.i8 (i8 &lt;src&gt;)
7287 declare i16 @llvm.cttz.i16(i16 &lt;src&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]7288 declare i32 @llvm.cttz.i32(i32 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]7289 declare i64 @llvm.cttz.i64(i64 &lt;src&gt;)
7290 declare i256 @llvm.cttz.i256(i256 &lt;src&gt;)
Owen Andersonf1ac4652011-07-01 21:52:38 +0000[diff] [blame]7291 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]7292</pre>
7293
7294<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7295<p>The '<tt>llvm.cttz</tt>' family of intrinsic functions counts the number of
7296 trailing zeros.</p>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]7297
7298<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7299<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]7300 integer type, or a vectory with integer element type.. The return type
7301 must match the argument type.</p>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]7302
7303<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7304<p>The '<tt>llvm.cttz</tt>' intrinsic counts the trailing (least significant)
Owen Andersonf1ac4652011-07-01 21:52:38 +0000[diff] [blame]7305 zeros in a variable, or within each element of a vector.
7306 If the src == 0 then the result is the size in bits of
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7307 the type of src. For example, <tt>llvm.cttz(2) = 1</tt>.</p>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]7308
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]7309</div>
7310
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7311</div>
7312
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]7313<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7314<h3>
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]7315 <a name="int_overflow">Arithmetic with Overflow Intrinsics</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7316</h3>
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]7317
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7318<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7319
7320<p>LLVM provides intrinsics for some arithmetic with overflow operations.</p>
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]7321
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7322<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7323<h4>
7324 <a name="int_sadd_overflow">
7325 '<tt>llvm.sadd.with.overflow.*</tt>' Intrinsics
7326 </a>
7327</h4>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7328
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7329<div>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7330
7331<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7332<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]7333 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7334
7335<pre>
7336 declare {i16, i1} @llvm.sadd.with.overflow.i16(i16 %a, i16 %b)
7337 declare {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
7338 declare {i64, i1} @llvm.sadd.with.overflow.i64(i64 %a, i64 %b)
7339</pre>
7340
7341<h5>Overview:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7342<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7343 a signed addition of the two arguments, and indicate whether an overflow
7344 occurred during the signed summation.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7345
7346<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7347<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]7348 be of integer types of any bit width, but they must have the same bit
7349 width. The second element of the result structure must be of
7350 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
7351 undergo signed addition.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7352
7353<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7354<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7355 a signed addition of the two variables. They return a structure &mdash; the
7356 first element of which is the signed summation, and the second element of
7357 which is a bit specifying if the signed summation resulted in an
7358 overflow.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7359
7360<h5>Examples:</h5>
7361<pre>
7362 %res = call {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
7363 %sum = extractvalue {i32, i1} %res, 0
7364 %obit = extractvalue {i32, i1} %res, 1
7365 br i1 %obit, label %overflow, label %normal
7366</pre>
7367
7368</div>
7369
7370<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7371<h4>
7372 <a name="int_uadd_overflow">
7373 '<tt>llvm.uadd.with.overflow.*</tt>' Intrinsics
7374 </a>
7375</h4>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7376
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7377<div>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7378
7379<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7380<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]7381 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7382
7383<pre>
7384 declare {i16, i1} @llvm.uadd.with.overflow.i16(i16 %a, i16 %b)
7385 declare {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
7386 declare {i64, i1} @llvm.uadd.with.overflow.i64(i64 %a, i64 %b)
7387</pre>
7388
7389<h5>Overview:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7390<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7391 an unsigned addition of the two arguments, and indicate whether a carry
7392 occurred during the unsigned summation.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7393
7394<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7395<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]7396 be of integer types of any bit width, but they must have the same bit
7397 width. The second element of the result structure must be of
7398 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
7399 undergo unsigned addition.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7400
7401<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7402<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7403 an unsigned addition of the two arguments. They return a structure &mdash;
7404 the first element of which is the sum, and the second element of which is a
7405 bit specifying if the unsigned summation resulted in a carry.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7406
7407<h5>Examples:</h5>
7408<pre>
7409 %res = call {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
7410 %sum = extractvalue {i32, i1} %res, 0
7411 %obit = extractvalue {i32, i1} %res, 1
7412 br i1 %obit, label %carry, label %normal
7413</pre>
7414
7415</div>
7416
7417<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7418<h4>
7419 <a name="int_ssub_overflow">
7420 '<tt>llvm.ssub.with.overflow.*</tt>' Intrinsics
7421 </a>
7422</h4>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7423
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7424<div>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7425
7426<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7427<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]7428 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7429
7430<pre>
7431 declare {i16, i1} @llvm.ssub.with.overflow.i16(i16 %a, i16 %b)
7432 declare {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
7433 declare {i64, i1} @llvm.ssub.with.overflow.i64(i64 %a, i64 %b)
7434</pre>
7435
7436<h5>Overview:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7437<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7438 a signed subtraction of the two arguments, and indicate whether an overflow
7439 occurred during the signed subtraction.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7440
7441<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7442<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]7443 be of integer types of any bit width, but they must have the same bit
7444 width. The second element of the result structure must be of
7445 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
7446 undergo signed subtraction.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7447
7448<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7449<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7450 a signed subtraction of the two arguments. They return a structure &mdash;
7451 the first element of which is the subtraction, and the second element of
7452 which is a bit specifying if the signed subtraction resulted in an
7453 overflow.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7454
7455<h5>Examples:</h5>
7456<pre>
7457 %res = call {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
7458 %sum = extractvalue {i32, i1} %res, 0
7459 %obit = extractvalue {i32, i1} %res, 1
7460 br i1 %obit, label %overflow, label %normal
7461</pre>
7462
7463</div>
7464
7465<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7466<h4>
7467 <a name="int_usub_overflow">
7468 '<tt>llvm.usub.with.overflow.*</tt>' Intrinsics
7469 </a>
7470</h4>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7471
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7472<div>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7473
7474<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7475<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]7476 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7477
7478<pre>
7479 declare {i16, i1} @llvm.usub.with.overflow.i16(i16 %a, i16 %b)
7480 declare {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
7481 declare {i64, i1} @llvm.usub.with.overflow.i64(i64 %a, i64 %b)
7482</pre>
7483
7484<h5>Overview:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7485<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7486 an unsigned subtraction of the two arguments, and indicate whether an
7487 overflow occurred during the unsigned subtraction.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7488
7489<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7490<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]7491 be of integer types of any bit width, but they must have the same bit
7492 width. The second element of the result structure must be of
7493 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
7494 undergo unsigned subtraction.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7495
7496<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7497<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7498 an unsigned subtraction of the two arguments. They return a structure &mdash;
7499 the first element of which is the subtraction, and the second element of
7500 which is a bit specifying if the unsigned subtraction resulted in an
7501 overflow.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7502
7503<h5>Examples:</h5>
7504<pre>
7505 %res = call {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
7506 %sum = extractvalue {i32, i1} %res, 0
7507 %obit = extractvalue {i32, i1} %res, 1
7508 br i1 %obit, label %overflow, label %normal
7509</pre>
7510
7511</div>
7512
7513<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7514<h4>
7515 <a name="int_smul_overflow">
7516 '<tt>llvm.smul.with.overflow.*</tt>' Intrinsics
7517 </a>
7518</h4>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7519
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7520<div>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7521
7522<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7523<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]7524 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7525
7526<pre>
7527 declare {i16, i1} @llvm.smul.with.overflow.i16(i16 %a, i16 %b)
7528 declare {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
7529 declare {i64, i1} @llvm.smul.with.overflow.i64(i64 %a, i64 %b)
7530</pre>
7531
7532<h5>Overview:</h5>
7533
7534<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7535 a signed multiplication of the two arguments, and indicate whether an
7536 overflow occurred during the signed multiplication.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7537
7538<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7539<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]7540 be of integer types of any bit width, but they must have the same bit
7541 width. The second element of the result structure must be of
7542 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
7543 undergo signed multiplication.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7544
7545<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7546<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7547 a signed multiplication of the two arguments. They return a structure &mdash;
7548 the first element of which is the multiplication, and the second element of
7549 which is a bit specifying if the signed multiplication resulted in an
7550 overflow.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7551
7552<h5>Examples:</h5>
7553<pre>
7554 %res = call {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
7555 %sum = extractvalue {i32, i1} %res, 0
7556 %obit = extractvalue {i32, i1} %res, 1
7557 br i1 %obit, label %overflow, label %normal
7558</pre>
7559
Reid Spencerf86037f2007-04-11 23:23:49 +0000[diff] [blame]7560</div>
7561
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]7562<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7563<h4>
7564 <a name="int_umul_overflow">
7565 '<tt>llvm.umul.with.overflow.*</tt>' Intrinsics
7566 </a>
7567</h4>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]7568
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7569<div>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]7570
7571<h5>Syntax:</h5>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]7572<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]7573 on any integer bit width.</p>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]7574
7575<pre>
7576 declare {i16, i1} @llvm.umul.with.overflow.i16(i16 %a, i16 %b)
7577 declare {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
7578 declare {i64, i1} @llvm.umul.with.overflow.i64(i64 %a, i64 %b)
7579</pre>
7580
7581<h5>Overview:</h5>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]7582<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7583 a unsigned multiplication of the two arguments, and indicate whether an
7584 overflow occurred during the unsigned multiplication.</p>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]7585
7586<h5>Arguments:</h5>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]7587<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]7588 be of integer types of any bit width, but they must have the same bit
7589 width. The second element of the result structure must be of
7590 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
7591 undergo unsigned multiplication.</p>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]7592
7593<h5>Semantics:</h5>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]7594<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7595 an unsigned multiplication of the two arguments. They return a structure
7596 &mdash; the first element of which is the multiplication, and the second
7597 element of which is a bit specifying if the unsigned multiplication resulted
7598 in an overflow.</p>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]7599
7600<h5>Examples:</h5>
7601<pre>
7602 %res = call {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
7603 %sum = extractvalue {i32, i1} %res, 0
7604 %obit = extractvalue {i32, i1} %res, 1
7605 br i1 %obit, label %overflow, label %normal
7606</pre>
7607
7608</div>
7609
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7610</div>
7611
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]7612<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7613<h3>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]7614 <a name="int_fp16">Half Precision Floating Point Intrinsics</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7615</h3>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]7616
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7617<div>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]7618
Chris Lattner0cec9c82010-03-15 04:12:21 +0000[diff] [blame]7619<p>Half precision floating point is a storage-only format. This means that it is
7620 a dense encoding (in memory) but does not support computation in the
7621 format.</p>
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]7622
Chris Lattner0cec9c82010-03-15 04:12:21 +0000[diff] [blame]7623<p>This means that code must first load the half-precision floating point
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]7624 value as an i16, then convert it to float with <a
7625 href="#int_convert_from_fp16"><tt>llvm.convert.from.fp16</tt></a>.
7626 Computation can then be performed on the float value (including extending to
Chris Lattner0cec9c82010-03-15 04:12:21 +0000[diff] [blame]7627 double etc). To store the value back to memory, it is first converted to
7628 float if needed, then converted to i16 with
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]7629 <a href="#int_convert_to_fp16"><tt>llvm.convert.to.fp16</tt></a>, then
7630 storing as an i16 value.</p>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]7631
7632<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7633<h4>
7634 <a name="int_convert_to_fp16">
7635 '<tt>llvm.convert.to.fp16</tt>' Intrinsic
7636 </a>
7637</h4>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]7638
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7639<div>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]7640
7641<h5>Syntax:</h5>
7642<pre>
7643 declare i16 @llvm.convert.to.fp16(f32 %a)
7644</pre>
7645
7646<h5>Overview:</h5>
7647<p>The '<tt>llvm.convert.to.fp16</tt>' intrinsic function performs
7648 a conversion from single precision floating point format to half precision
7649 floating point format.</p>
7650
7651<h5>Arguments:</h5>
7652<p>The intrinsic function contains single argument - the value to be
7653 converted.</p>
7654
7655<h5>Semantics:</h5>
7656<p>The '<tt>llvm.convert.to.fp16</tt>' intrinsic function performs
7657 a conversion from single precision floating point format to half precision
Chris Lattner0cec9c82010-03-15 04:12:21 +0000[diff] [blame]7658 floating point format. The return value is an <tt>i16</tt> which
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]7659 contains the converted number.</p>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]7660
7661<h5>Examples:</h5>
7662<pre>
7663 %res = call i16 @llvm.convert.to.fp16(f32 %a)
7664 store i16 %res, i16* @x, align 2
7665</pre>
7666
7667</div>
7668
7669<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7670<h4>
7671 <a name="int_convert_from_fp16">
7672 '<tt>llvm.convert.from.fp16</tt>' Intrinsic
7673 </a>
7674</h4>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]7675
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7676<div>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]7677
7678<h5>Syntax:</h5>
7679<pre>
7680 declare f32 @llvm.convert.from.fp16(i16 %a)
7681</pre>
7682
7683<h5>Overview:</h5>
7684<p>The '<tt>llvm.convert.from.fp16</tt>' intrinsic function performs
7685 a conversion from half precision floating point format to single precision
7686 floating point format.</p>
7687
7688<h5>Arguments:</h5>
7689<p>The intrinsic function contains single argument - the value to be
7690 converted.</p>
7691
7692<h5>Semantics:</h5>
7693<p>The '<tt>llvm.convert.from.fp16</tt>' intrinsic function performs a
Chris Lattner0cec9c82010-03-15 04:12:21 +0000[diff] [blame]7694 conversion from half single precision floating point format to single
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]7695 precision floating point format. The input half-float value is represented by
7696 an <tt>i16</tt> value.</p>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]7697
7698<h5>Examples:</h5>
7699<pre>
7700 %a = load i16* @x, align 2
7701 %res = call f32 @llvm.convert.from.fp16(i16 %a)
7702</pre>
7703
7704</div>
7705
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7706</div>
7707
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]7708<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7709<h3>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]7710 <a name="int_debugger">Debugger Intrinsics</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7711</h3>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]7712
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7713<div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]7714
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7715<p>The LLVM debugger intrinsics (which all start with <tt>llvm.dbg.</tt>
7716 prefix), are described in
7717 the <a href="SourceLevelDebugging.html#format_common_intrinsics">LLVM Source
7718 Level Debugging</a> document.</p>
7719
7720</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]7721
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]7722<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7723<h3>
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]7724 <a name="int_eh">Exception Handling Intrinsics</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7725</h3>
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]7726
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7727<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7728
7729<p>The LLVM exception handling intrinsics (which all start with
7730 <tt>llvm.eh.</tt> prefix), are described in
7731 the <a href="ExceptionHandling.html#format_common_intrinsics">LLVM Exception
7732 Handling</a> document.</p>
7733
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]7734</div>
7735
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]7736<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7737<h3>
Duncan Sands4a544a72011-09-06 13:37:06 +0000[diff] [blame]7738 <a name="int_trampoline">Trampoline Intrinsics</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7739</h3>
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]7740
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7741<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7742
Duncan Sands4a544a72011-09-06 13:37:06 +0000[diff] [blame]7743<p>These intrinsics make it possible to excise one parameter, marked with
Dan Gohmanff235352010-07-02 23:18:08 +0000[diff] [blame]7744 the <a href="#nest"><tt>nest</tt></a> attribute, from a function.
7745 The result is a callable
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7746 function pointer lacking the nest parameter - the caller does not need to
7747 provide a value for it. Instead, the value to use is stored in advance in a
7748 "trampoline", a block of memory usually allocated on the stack, which also
7749 contains code to splice the nest value into the argument list. This is used
7750 to implement the GCC nested function address extension.</p>
7751
7752<p>For example, if the function is
7753 <tt>i32 f(i8* nest %c, i32 %x, i32 %y)</tt> then the resulting function
7754 pointer has signature <tt>i32 (i32, i32)*</tt>. It can be created as
7755 follows:</p>
7756
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]7757<pre class="doc_code">
Duncan Sandsf7331b32007-09-11 14:10:23 +0000[diff] [blame]7758 %tramp = alloca [10 x i8], align 4 ; size and alignment only correct for X86
7759 %tramp1 = getelementptr [10 x i8]* %tramp, i32 0, i32 0
Duncan Sands4a544a72011-09-06 13:37:06 +0000[diff] [blame]7760 call i8* @llvm.init.trampoline(i8* %tramp1, i8* bitcast (i32 (i8*, i32, i32)* @f to i8*), i8* %nval)
7761 %p = call i8* @llvm.adjust.trampoline(i8* %tramp1)
Duncan Sandsf7331b32007-09-11 14:10:23 +0000[diff] [blame]7762 %fp = bitcast i8* %p to i32 (i32, i32)*
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]7763</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7764
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7765<p>The call <tt>%val = call i32 %fp(i32 %x, i32 %y)</tt> is then equivalent
7766 to <tt>%val = call i32 %f(i8* %nval, i32 %x, i32 %y)</tt>.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7767
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]7768<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7769<h4>
7770 <a name="int_it">
7771 '<tt>llvm.init.trampoline</tt>' Intrinsic
7772 </a>
7773</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7774
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7775<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7776
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]7777<h5>Syntax:</h5>
7778<pre>
Duncan Sands4a544a72011-09-06 13:37:06 +0000[diff] [blame]7779 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]7780</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7781
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]7782<h5>Overview:</h5>
Duncan Sands4a544a72011-09-06 13:37:06 +0000[diff] [blame]7783<p>This fills the memory pointed to by <tt>tramp</tt> with executable code,
7784 turning it into a trampoline.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7785
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]7786<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7787<p>The <tt>llvm.init.trampoline</tt> intrinsic takes three arguments, all
7788 pointers. The <tt>tramp</tt> argument must point to a sufficiently large and
7789 sufficiently aligned block of memory; this memory is written to by the
7790 intrinsic. Note that the size and the alignment are target-specific - LLVM
7791 currently provides no portable way of determining them, so a front-end that
7792 generates this intrinsic needs to have some target-specific knowledge.
7793 The <tt>func</tt> argument must hold a function bitcast to
7794 an <tt>i8*</tt>.</p>
7795
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]7796<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7797<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]7798 dependent code, turning it into a function. Then <tt>tramp</tt> needs to be
7799 passed to <a href="#int_at">llvm.adjust.trampoline</a> to get a pointer
7800 which can be <a href="#int_trampoline">bitcast (to a new function) and
7801 called</a>. The new function's signature is the same as that of
7802 <tt>func</tt> with any arguments marked with the <tt>nest</tt> attribute
7803 removed. At most one such <tt>nest</tt> argument is allowed, and it must be of
7804 pointer type. Calling the new function is equivalent to calling <tt>func</tt>
7805 with the same argument list, but with <tt>nval</tt> used for the missing
7806 <tt>nest</tt> argument. If, after calling <tt>llvm.init.trampoline</tt>, the
7807 memory pointed to by <tt>tramp</tt> is modified, then the effect of any later call
7808 to the returned function pointer is undefined.</p>
7809</div>
7810
7811<!-- _______________________________________________________________________ -->
7812<h4>
7813 <a name="int_at">
7814 '<tt>llvm.adjust.trampoline</tt>' Intrinsic
7815 </a>
7816</h4>
7817
7818<div>
7819
7820<h5>Syntax:</h5>
7821<pre>
7822 declare i8* @llvm.adjust.trampoline(i8* &lt;tramp&gt;)
7823</pre>
7824
7825<h5>Overview:</h5>
7826<p>This performs any required machine-specific adjustment to the address of a
7827 trampoline (passed as <tt>tramp</tt>).</p>
7828
7829<h5>Arguments:</h5>
7830<p><tt>tramp</tt> must point to a block of memory which already has trampoline code
7831 filled in by a previous call to <a href="#int_it"><tt>llvm.init.trampoline</tt>
7832 </a>.</p>
7833
7834<h5>Semantics:</h5>
7835<p>On some architectures the address of the code to be executed needs to be
7836 different to the address where the trampoline is actually stored. This
7837 intrinsic returns the executable address corresponding to <tt>tramp</tt>
7838 after performing the required machine specific adjustments.
7839 The pointer returned can then be <a href="#int_trampoline"> bitcast and
7840 executed</a>.
7841</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7842
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]7843</div>
7844
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7845</div>
7846
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]7847<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7848<h3>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7849 <a name="int_memorymarkers">Memory Use Markers</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7850</h3>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7851
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7852<div>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7853
7854<p>This class of intrinsics exists to information about the lifetime of memory
7855 objects and ranges where variables are immutable.</p>
7856
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7857<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7858<h4>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7859 <a name="int_lifetime_start">'<tt>llvm.lifetime.start</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7860</h4>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7861
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7862<div>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7863
7864<h5>Syntax:</h5>
7865<pre>
7866 declare void @llvm.lifetime.start(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7867</pre>
7868
7869<h5>Overview:</h5>
7870<p>The '<tt>llvm.lifetime.start</tt>' intrinsic specifies the start of a memory
7871 object's lifetime.</p>
7872
7873<h5>Arguments:</h5>
Nick Lewycky321333e2009-10-13 07:57:33 +0000[diff] [blame]7874<p>The first argument is a constant integer representing the size of the
7875 object, or -1 if it is variable sized. The second argument is a pointer to
7876 the object.</p>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7877
7878<h5>Semantics:</h5>
7879<p>This intrinsic indicates that before this point in the code, the value of the
7880 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]7881 never be used and has an undefined value. A load from the pointer that
7882 precedes this intrinsic can be replaced with
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7883 <tt>'<a href="#undefvalues">undef</a>'</tt>.</p>
7884
7885</div>
7886
7887<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7888<h4>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7889 <a name="int_lifetime_end">'<tt>llvm.lifetime.end</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7890</h4>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7891
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7892<div>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7893
7894<h5>Syntax:</h5>
7895<pre>
7896 declare void @llvm.lifetime.end(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7897</pre>
7898
7899<h5>Overview:</h5>
7900<p>The '<tt>llvm.lifetime.end</tt>' intrinsic specifies the end of a memory
7901 object's lifetime.</p>
7902
7903<h5>Arguments:</h5>
Nick Lewycky321333e2009-10-13 07:57:33 +0000[diff] [blame]7904<p>The first argument is a constant integer representing the size of the
7905 object, or -1 if it is variable sized. The second argument is a pointer to
7906 the object.</p>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7907
7908<h5>Semantics:</h5>
7909<p>This intrinsic indicates that after this point in the code, the value of the
7910 memory pointed to by <tt>ptr</tt> is dead. This means that it is known to
7911 never be used and has an undefined value. Any stores into the memory object
7912 following this intrinsic may be removed as dead.
7913
7914</div>
7915
7916<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7917<h4>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7918 <a name="int_invariant_start">'<tt>llvm.invariant.start</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7919</h4>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7920
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7921<div>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7922
7923<h5>Syntax:</h5>
7924<pre>
Nick Lewycky29b6cb42010-11-30 04:13:41 +0000[diff] [blame]7925 declare {}* @llvm.invariant.start(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7926</pre>
7927
7928<h5>Overview:</h5>
7929<p>The '<tt>llvm.invariant.start</tt>' intrinsic specifies that the contents of
7930 a memory object will not change.</p>
7931
7932<h5>Arguments:</h5>
Nick Lewycky321333e2009-10-13 07:57:33 +0000[diff] [blame]7933<p>The first argument is a constant integer representing the size of the
7934 object, or -1 if it is variable sized. The second argument is a pointer to
7935 the object.</p>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7936
7937<h5>Semantics:</h5>
7938<p>This intrinsic indicates that until an <tt>llvm.invariant.end</tt> that uses
7939 the return value, the referenced memory location is constant and
7940 unchanging.</p>
7941
7942</div>
7943
7944<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7945<h4>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7946 <a name="int_invariant_end">'<tt>llvm.invariant.end</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7947</h4>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7948
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7949<div>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7950
7951<h5>Syntax:</h5>
7952<pre>
7953 declare void @llvm.invariant.end({}* &lt;start&gt;, i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7954</pre>
7955
7956<h5>Overview:</h5>
7957<p>The '<tt>llvm.invariant.end</tt>' intrinsic specifies that the contents of
7958 a memory object are mutable.</p>
7959
7960<h5>Arguments:</h5>
7961<p>The first argument is the matching <tt>llvm.invariant.start</tt> intrinsic.
Nick Lewycky321333e2009-10-13 07:57:33 +0000[diff] [blame]7962 The second argument is a constant integer representing the size of the
7963 object, or -1 if it is variable sized and the third argument is a pointer
7964 to the object.</p>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7965
7966<h5>Semantics:</h5>
7967<p>This intrinsic indicates that the memory is mutable again.</p>
7968
7969</div>
7970
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7971</div>
7972
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7973<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7974<h3>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]7975 <a name="int_general">General Intrinsics</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7976</h3>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]7977
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7978<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7979
7980<p>This class of intrinsics is designed to be generic and has no specific
7981 purpose.</p>
7982
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]7983<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7984<h4>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]7985 <a name="int_var_annotation">'<tt>llvm.var.annotation</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7986</h4>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]7987
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7988<div>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]7989
7990<h5>Syntax:</h5>
7991<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7992 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]7993</pre>
7994
7995<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7996<p>The '<tt>llvm.var.annotation</tt>' intrinsic.</p>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]7997
7998<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7999<p>The first argument is a pointer to a value, the second is a pointer to a
8000 global string, the third is a pointer to a global string which is the source
8001 file name, and the last argument is the line number.</p>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]8002
8003<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8004<p>This intrinsic allows annotation of local variables with arbitrary strings.
8005 This can be useful for special purpose optimizations that want to look for
John Criswelle865c032011-08-19 16:57:55 +0000[diff] [blame]8006 these annotations. These have no other defined use; they are ignored by code
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8007 generation and optimization.</p>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]8008
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]8009</div>
8010
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]8011<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8012<h4>
Tanya Lattnere1a8da02007-09-21 23:57:59 +0000[diff] [blame]8013 <a name="int_annotation">'<tt>llvm.annotation.*</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8014</h4>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]8015
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8016<div>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]8017
8018<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8019<p>This is an overloaded intrinsic. You can use '<tt>llvm.annotation</tt>' on
8020 any integer bit width.</p>
8021
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]8022<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]8023 declare i8 @llvm.annotation.i8(i8 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
8024 declare i16 @llvm.annotation.i16(i16 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
8025 declare i32 @llvm.annotation.i32(i32 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
8026 declare i64 @llvm.annotation.i64(i64 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
8027 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]8028</pre>
8029
8030<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8031<p>The '<tt>llvm.annotation</tt>' intrinsic.</p>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]8032
8033<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8034<p>The first argument is an integer value (result of some expression), the
8035 second is a pointer to a global string, the third is a pointer to a global
8036 string which is the source file name, and the last argument is the line
8037 number. It returns the value of the first argument.</p>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]8038
8039<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8040<p>This intrinsic allows annotations to be put on arbitrary expressions with
8041 arbitrary strings. This can be useful for special purpose optimizations that
John Criswelle865c032011-08-19 16:57:55 +0000[diff] [blame]8042 want to look for these annotations. These have no other defined use; they
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8043 are ignored by code generation and optimization.</p>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]8044
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]8045</div>
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]8046
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]8047<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8048<h4>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]8049 <a name="int_trap">'<tt>llvm.trap</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8050</h4>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]8051
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8052<div>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]8053
8054<h5>Syntax:</h5>
8055<pre>
8056 declare void @llvm.trap()
8057</pre>
8058
8059<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8060<p>The '<tt>llvm.trap</tt>' intrinsic.</p>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]8061
8062<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8063<p>None.</p>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]8064
8065<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8066<p>This intrinsics is lowered to the target dependent trap instruction. If the
8067 target does not have a trap instruction, this intrinsic will be lowered to
8068 the call of the <tt>abort()</tt> function.</p>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]8069
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]8070</div>
8071
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]8072<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8073<h4>
Misha Brukmandccb0252008-11-22 23:55:29 +0000[diff] [blame]8074 <a name="int_stackprotector">'<tt>llvm.stackprotector</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8075</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8076
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8077<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8078
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]8079<h5>Syntax:</h5>
8080<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]8081 declare void @llvm.stackprotector(i8* &lt;guard&gt;, i8** &lt;slot&gt;)
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]8082</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8083
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]8084<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8085<p>The <tt>llvm.stackprotector</tt> intrinsic takes the <tt>guard</tt> and
8086 stores it onto the stack at <tt>slot</tt>. The stack slot is adjusted to
8087 ensure that it is placed on the stack before local variables.</p>
8088
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]8089<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8090<p>The <tt>llvm.stackprotector</tt> intrinsic requires two pointer
8091 arguments. The first argument is the value loaded from the stack
8092 guard <tt>@__stack_chk_guard</tt>. The second variable is an <tt>alloca</tt>
8093 that has enough space to hold the value of the guard.</p>
8094
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]8095<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8096<p>This intrinsic causes the prologue/epilogue inserter to force the position of
8097 the <tt>AllocaInst</tt> stack slot to be before local variables on the
8098 stack. This is to ensure that if a local variable on the stack is
8099 overwritten, it will destroy the value of the guard. When the function exits,
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]8100 the guard on the stack is checked against the original guard. If they are
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8101 different, then the program aborts by calling the <tt>__stack_chk_fail()</tt>
8102 function.</p>
8103
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]8104</div>
8105
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]8106<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8107<h4>
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]8108 <a name="int_objectsize">'<tt>llvm.objectsize</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8109</h4>
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]8110
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8111<div>
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]8112
8113<h5>Syntax:</h5>
8114<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]8115 declare i32 @llvm.objectsize.i32(i8* &lt;object&gt;, i1 &lt;type&gt;)
8116 declare i64 @llvm.objectsize.i64(i8* &lt;object&gt;, i1 &lt;type&gt;)
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]8117</pre>
8118
8119<h5>Overview:</h5>
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]8120<p>The <tt>llvm.objectsize</tt> intrinsic is designed to provide information to
8121 the optimizers to determine at compile time whether a) an operation (like
8122 memcpy) will overflow a buffer that corresponds to an object, or b) that a
8123 runtime check for overflow isn't necessary. An object in this context means
8124 an allocation of a specific class, structure, array, or other object.</p>
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]8125
8126<h5>Arguments:</h5>
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]8127<p>The <tt>llvm.objectsize</tt> intrinsic takes two arguments. The first
Eric Christopher8295a0a2009-12-23 00:29:49 +0000[diff] [blame]8128 argument is a pointer to or into the <tt>object</tt>. The second argument
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]8129 is a boolean 0 or 1. This argument determines whether you want the
8130 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]8131 1, variables are not allowed.</p>
8132
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]8133<h5>Semantics:</h5>
8134<p>The <tt>llvm.objectsize</tt> intrinsic is lowered to either a constant
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]8135 representing the size of the object concerned, or <tt>i32/i64 -1 or 0</tt>,
8136 depending on the <tt>type</tt> argument, if the size cannot be determined at
8137 compile time.</p>
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]8138
8139</div>
8140
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8141</div>
8142
8143</div>
8144
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]8145<!-- *********************************************************************** -->
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]8146<hr>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]8147<address>
8148 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
Misha Brukman44408702008-12-11 17:34:48 +0000[diff] [blame]8149 src="http://jigsaw.w3.org/css-validator/images/vcss-blue" alt="Valid CSS"></a>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]8150 <a href="http://validator.w3.org/check/referer"><img
Misha Brukman44408702008-12-11 17:34:48 +0000[diff] [blame]8151 src="http://www.w3.org/Icons/valid-html401-blue" alt="Valid HTML 4.01"></a>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]8152
8153 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
NAKAMURA Takumib9a33632011-04-09 02:13:37 +0000[diff] [blame]8154 <a href="http://llvm.org/">The LLVM Compiler Infrastructure</a><br>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]8155 Last modified: $Date$
8156</address>
Chris Lattnerc7d3ab32008-01-04 04:33:49 +0000[diff] [blame]8157
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]8158</body>
8159</html>