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gerrit-public.fairphone.software / platform / external / llvm / 7bc389b6b00e26e07fa5ac64e43d9b06b73828c1 / . / 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>
Peter Collingbourne999f90b2011-10-27 19:19:14 +0000[diff] [blame]106 <li><a href="#fpaccuracy">'<tt>fpaccuracy</tt>' Metadata</a></li>
Peter Collingbourne249d9532011-10-27 19:19:07 +0000[diff] [blame]107 </ol>
108 </li>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]109 </ol>
110 </li>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]111 <li><a href="#intrinsic_globals">Intrinsic Global Variables</a>
112 <ol>
113 <li><a href="#intg_used">The '<tt>llvm.used</tt>' Global Variable</a></li>
Chris Lattner401e10c2009-07-20 06:14:25 +0000[diff] [blame]114 <li><a href="#intg_compiler_used">The '<tt>llvm.compiler.used</tt>'
115 Global Variable</a></li>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]116 <li><a href="#intg_global_ctors">The '<tt>llvm.global_ctors</tt>'
117 Global Variable</a></li>
118 <li><a href="#intg_global_dtors">The '<tt>llvm.global_dtors</tt>'
119 Global Variable</a></li>
120 </ol>
121 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]122 <li><a href="#instref">Instruction Reference</a>
123 <ol>
124 <li><a href="#terminators">Terminator Instructions</a>
125 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]126 <li><a href="#i_ret">'<tt>ret</tt>' Instruction</a></li>
127 <li><a href="#i_br">'<tt>br</tt>' Instruction</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]128 <li><a href="#i_switch">'<tt>switch</tt>' Instruction</a></li>
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]129 <li><a href="#i_indirectbr">'<tt>indirectbr</tt>' Instruction</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]130 <li><a href="#i_invoke">'<tt>invoke</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]131 <li><a href="#i_unwind">'<tt>unwind</tt>' Instruction</a></li>
Bill Wendlingdccc03b2011-07-31 06:30:59 +0000[diff] [blame]132 <li><a href="#i_resume">'<tt>resume</tt>' Instruction</a></li>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]133 <li><a href="#i_unreachable">'<tt>unreachable</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]134 </ol>
135 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]136 <li><a href="#binaryops">Binary Operations</a>
137 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]138 <li><a href="#i_add">'<tt>add</tt>' Instruction</a></li>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]139 <li><a href="#i_fadd">'<tt>fadd</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]140 <li><a href="#i_sub">'<tt>sub</tt>' Instruction</a></li>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]141 <li><a href="#i_fsub">'<tt>fsub</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]142 <li><a href="#i_mul">'<tt>mul</tt>' Instruction</a></li>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]143 <li><a href="#i_fmul">'<tt>fmul</tt>' Instruction</a></li>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]144 <li><a href="#i_udiv">'<tt>udiv</tt>' Instruction</a></li>
145 <li><a href="#i_sdiv">'<tt>sdiv</tt>' Instruction</a></li>
146 <li><a href="#i_fdiv">'<tt>fdiv</tt>' Instruction</a></li>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]147 <li><a href="#i_urem">'<tt>urem</tt>' Instruction</a></li>
148 <li><a href="#i_srem">'<tt>srem</tt>' Instruction</a></li>
149 <li><a href="#i_frem">'<tt>frem</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]150 </ol>
151 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]152 <li><a href="#bitwiseops">Bitwise Binary Operations</a>
153 <ol>
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]154 <li><a href="#i_shl">'<tt>shl</tt>' Instruction</a></li>
155 <li><a href="#i_lshr">'<tt>lshr</tt>' Instruction</a></li>
156 <li><a href="#i_ashr">'<tt>ashr</tt>' Instruction</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]157 <li><a href="#i_and">'<tt>and</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]158 <li><a href="#i_or">'<tt>or</tt>' Instruction</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]159 <li><a href="#i_xor">'<tt>xor</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]160 </ol>
161 </li>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]162 <li><a href="#vectorops">Vector Operations</a>
163 <ol>
164 <li><a href="#i_extractelement">'<tt>extractelement</tt>' Instruction</a></li>
165 <li><a href="#i_insertelement">'<tt>insertelement</tt>' Instruction</a></li>
166 <li><a href="#i_shufflevector">'<tt>shufflevector</tt>' Instruction</a></li>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]167 </ol>
168 </li>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]169 <li><a href="#aggregateops">Aggregate Operations</a>
170 <ol>
171 <li><a href="#i_extractvalue">'<tt>extractvalue</tt>' Instruction</a></li>
172 <li><a href="#i_insertvalue">'<tt>insertvalue</tt>' Instruction</a></li>
173 </ol>
174 </li>
Chris Lattner884a9702006-08-15 00:45:58 +0000[diff] [blame]175 <li><a href="#memoryops">Memory Access and Addressing Operations</a>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]176 <ol>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]177 <li><a href="#i_alloca">'<tt>alloca</tt>' Instruction</a></li>
178 <li><a href="#i_load">'<tt>load</tt>' Instruction</a></li>
179 <li><a href="#i_store">'<tt>store</tt>' Instruction</a></li>
180 <li><a href="#i_fence">'<tt>fence</tt>' Instruction</a></li>
181 <li><a href="#i_cmpxchg">'<tt>cmpxchg</tt>' Instruction</a></li>
182 <li><a href="#i_atomicrmw">'<tt>atomicrmw</tt>' Instruction</a></li>
Robert Bocchino7b81c752006-02-17 21:18:08 +0000[diff] [blame]183 <li><a href="#i_getelementptr">'<tt>getelementptr</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]184 </ol>
185 </li>
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]186 <li><a href="#convertops">Conversion Operations</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]187 <ol>
188 <li><a href="#i_trunc">'<tt>trunc .. to</tt>' Instruction</a></li>
189 <li><a href="#i_zext">'<tt>zext .. to</tt>' Instruction</a></li>
190 <li><a href="#i_sext">'<tt>sext .. to</tt>' Instruction</a></li>
191 <li><a href="#i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a></li>
192 <li><a href="#i_fpext">'<tt>fpext .. to</tt>' Instruction</a></li>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]193 <li><a href="#i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a></li>
194 <li><a href="#i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a></li>
195 <li><a href="#i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a></li>
196 <li><a href="#i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a></li>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]197 <li><a href="#i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a></li>
198 <li><a href="#i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a></li>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]199 <li><a href="#i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a></li>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]200 </ol>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]201 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]202 <li><a href="#otherops">Other Operations</a>
203 <ol>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]204 <li><a href="#i_icmp">'<tt>icmp</tt>' Instruction</a></li>
205 <li><a href="#i_fcmp">'<tt>fcmp</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]206 <li><a href="#i_phi">'<tt>phi</tt>' Instruction</a></li>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]207 <li><a href="#i_select">'<tt>select</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]208 <li><a href="#i_call">'<tt>call</tt>' Instruction</a></li>
Chris Lattnerfb6977d2006-01-13 23:26:01 +0000[diff] [blame]209 <li><a href="#i_va_arg">'<tt>va_arg</tt>' Instruction</a></li>
Bill Wendlingf78faf82011-08-02 21:52:38 +0000[diff] [blame]210 <li><a href="#i_landingpad">'<tt>landingpad</tt>' Instruction</a></li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]211 </ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]212 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]213 </ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]214 </li>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]215 <li><a href="#intrinsics">Intrinsic Functions</a>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]216 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]217 <li><a href="#int_varargs">Variable Argument Handling Intrinsics</a>
218 <ol>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]219 <li><a href="#int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a></li>
220 <li><a href="#int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a></li>
221 <li><a href="#int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]222 </ol>
223 </li>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]224 <li><a href="#int_gc">Accurate Garbage Collection Intrinsics</a>
225 <ol>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]226 <li><a href="#int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a></li>
227 <li><a href="#int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a></li>
228 <li><a href="#int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a></li>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]229 </ol>
230 </li>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]231 <li><a href="#int_codegen">Code Generator Intrinsics</a>
232 <ol>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]233 <li><a href="#int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a></li>
234 <li><a href="#int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a></li>
235 <li><a href="#int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a></li>
236 <li><a href="#int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a></li>
237 <li><a href="#int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a></li>
238 <li><a href="#int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a></li>
Dan Gohman31f1af12010-05-26 21:56:15 +0000[diff] [blame]239 <li><a href="#int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a></li>
John Criswell7123e272004-04-09 16:43:20 +0000[diff] [blame]240 </ol>
241 </li>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]242 <li><a href="#int_libc">Standard C Library Intrinsics</a>
243 <ol>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]244 <li><a href="#int_memcpy">'<tt>llvm.memcpy.*</tt>' Intrinsic</a></li>
245 <li><a href="#int_memmove">'<tt>llvm.memmove.*</tt>' Intrinsic</a></li>
246 <li><a href="#int_memset">'<tt>llvm.memset.*</tt>' Intrinsic</a></li>
247 <li><a href="#int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a></li>
248 <li><a href="#int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a></li>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]249 <li><a href="#int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a></li>
250 <li><a href="#int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a></li>
251 <li><a href="#int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a></li>
Dan Gohman08b280b2011-05-27 00:36:31 +0000[diff] [blame]252 <li><a href="#int_exp">'<tt>llvm.exp.*</tt>' Intrinsic</a></li>
253 <li><a href="#int_log">'<tt>llvm.log.*</tt>' Intrinsic</a></li>
Cameron Zwarich33390842011-07-08 21:39:21 +0000[diff] [blame]254 <li><a href="#int_fma">'<tt>llvm.fma.*</tt>' Intrinsic</a></li>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]255 </ol>
256 </li>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]257 <li><a href="#int_manip">Bit Manipulation Intrinsics</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]258 <ol>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]259 <li><a href="#int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a></li>
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]260 <li><a href="#int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic </a></li>
261 <li><a href="#int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic </a></li>
262 <li><a href="#int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic </a></li>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]263 </ol>
264 </li>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]265 <li><a href="#int_overflow">Arithmetic with Overflow Intrinsics</a>
266 <ol>
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]267 <li><a href="#int_sadd_overflow">'<tt>llvm.sadd.with.overflow.*</tt> Intrinsics</a></li>
268 <li><a href="#int_uadd_overflow">'<tt>llvm.uadd.with.overflow.*</tt> Intrinsics</a></li>
269 <li><a href="#int_ssub_overflow">'<tt>llvm.ssub.with.overflow.*</tt> Intrinsics</a></li>
270 <li><a href="#int_usub_overflow">'<tt>llvm.usub.with.overflow.*</tt> Intrinsics</a></li>
271 <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]272 <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]273 </ol>
274 </li>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]275 <li><a href="#int_fp16">Half Precision Floating Point Intrinsics</a>
276 <ol>
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]277 <li><a href="#int_convert_to_fp16">'<tt>llvm.convert.to.fp16</tt>' Intrinsic</a></li>
278 <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]279 </ol>
280 </li>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]281 <li><a href="#int_debugger">Debugger intrinsics</a></li>
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]282 <li><a href="#int_eh">Exception Handling intrinsics</a></li>
Duncan Sands4a544a72011-09-06 13:37:06 +0000[diff] [blame]283 <li><a href="#int_trampoline">Trampoline Intrinsics</a>
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]284 <ol>
285 <li><a href="#int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a></li>
Duncan Sands4a544a72011-09-06 13:37:06 +0000[diff] [blame]286 <li><a href="#int_at">'<tt>llvm.adjust.trampoline</tt>' Intrinsic</a></li>
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]287 </ol>
288 </li>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]289 <li><a href="#int_memorymarkers">Memory Use Markers</a>
290 <ol>
291 <li><a href="#int_lifetime_start"><tt>llvm.lifetime.start</tt></a></li>
292 <li><a href="#int_lifetime_end"><tt>llvm.lifetime.end</tt></a></li>
293 <li><a href="#int_invariant_start"><tt>llvm.invariant.start</tt></a></li>
294 <li><a href="#int_invariant_end"><tt>llvm.invariant.end</tt></a></li>
295 </ol>
296 </li>
Reid Spencer20677642007-07-20 19:59:11 +0000[diff] [blame]297 <li><a href="#int_general">General intrinsics</a>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]298 <ol>
Reid Spencer20677642007-07-20 19:59:11 +0000[diff] [blame]299 <li><a href="#int_var_annotation">
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]300 '<tt>llvm.var.annotation</tt>' Intrinsic</a></li>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]301 <li><a href="#int_annotation">
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]302 '<tt>llvm.annotation.*</tt>' Intrinsic</a></li>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]303 <li><a href="#int_trap">
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]304 '<tt>llvm.trap</tt>' Intrinsic</a></li>
305 <li><a href="#int_stackprotector">
306 '<tt>llvm.stackprotector</tt>' Intrinsic</a></li>
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]307 <li><a href="#int_objectsize">
308 '<tt>llvm.objectsize</tt>' Intrinsic</a></li>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]309 </ol>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]310 </li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]311 </ol>
312 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]313</ol>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]314
315<div class="doc_author">
316 <p>Written by <a href="mailto:sabre@nondot.org">Chris Lattner</a>
317 and <a href="mailto:vadve@cs.uiuc.edu">Vikram Adve</a></p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]318</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]319
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]320<!-- *********************************************************************** -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]321<h2><a name="abstract">Abstract</a></h2>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]322<!-- *********************************************************************** -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]323
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]324<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]325
326<p>This document is a reference manual for the LLVM assembly language. LLVM is
327 a Static Single Assignment (SSA) based representation that provides type
328 safety, low-level operations, flexibility, and the capability of representing
329 'all' high-level languages cleanly. It is the common code representation
330 used throughout all phases of the LLVM compilation strategy.</p>
331
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]332</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]333
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]334<!-- *********************************************************************** -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]335<h2><a name="introduction">Introduction</a></h2>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]336<!-- *********************************************************************** -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]337
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]338<div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]339
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]340<p>The LLVM code representation is designed to be used in three different forms:
341 as an in-memory compiler IR, as an on-disk bitcode representation (suitable
342 for fast loading by a Just-In-Time compiler), and as a human readable
343 assembly language representation. This allows LLVM to provide a powerful
344 intermediate representation for efficient compiler transformations and
345 analysis, while providing a natural means to debug and visualize the
346 transformations. The three different forms of LLVM are all equivalent. This
347 document describes the human readable representation and notation.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]348
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]349<p>The LLVM representation aims to be light-weight and low-level while being
350 expressive, typed, and extensible at the same time. It aims to be a
351 "universal IR" of sorts, by being at a low enough level that high-level ideas
352 may be cleanly mapped to it (similar to how microprocessors are "universal
353 IR's", allowing many source languages to be mapped to them). By providing
354 type information, LLVM can be used as the target of optimizations: for
355 example, through pointer analysis, it can be proven that a C automatic
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]356 variable is never accessed outside of the current function, allowing it to
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]357 be promoted to a simple SSA value instead of a memory location.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]358
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]359<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]360<h4>
361 <a name="wellformed">Well-Formedness</a>
362</h4>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]363
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]364<div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]365
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]366<p>It is important to note that this document describes 'well formed' LLVM
367 assembly language. There is a difference between what the parser accepts and
368 what is considered 'well formed'. For example, the following instruction is
369 syntactically okay, but not well formed:</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]370
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]371<pre class="doc_code">
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]372%x = <a href="#i_add">add</a> i32 1, %x
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]373</pre>
374
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]375<p>because the definition of <tt>%x</tt> does not dominate all of its uses. The
376 LLVM infrastructure provides a verification pass that may be used to verify
377 that an LLVM module is well formed. This pass is automatically run by the
378 parser after parsing input assembly and by the optimizer before it outputs
379 bitcode. The violations pointed out by the verifier pass indicate bugs in
380 transformation passes or input to the parser.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]381
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]382</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]383
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]384</div>
385
Chris Lattnercc689392007-10-03 17:34:29 +0000[diff] [blame]386<!-- Describe the typesetting conventions here. -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]387
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]388<!-- *********************************************************************** -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]389<h2><a name="identifiers">Identifiers</a></h2>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]390<!-- *********************************************************************** -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]391
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]392<div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]393
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]394<p>LLVM identifiers come in two basic types: global and local. Global
395 identifiers (functions, global variables) begin with the <tt>'@'</tt>
396 character. Local identifiers (register names, types) begin with
397 the <tt>'%'</tt> character. Additionally, there are three different formats
398 for identifiers, for different purposes:</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]399
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]400<ol>
Reid Spencer2c452282007-08-07 14:34:28 +0000[diff] [blame]401 <li>Named values are represented as a string of characters with their prefix.
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]402 For example, <tt>%foo</tt>, <tt>@DivisionByZero</tt>,
403 <tt>%a.really.long.identifier</tt>. The actual regular expression used is
404 '<tt>[%@][a-zA-Z$._][a-zA-Z$._0-9]*</tt>'. Identifiers which require
405 other characters in their names can be surrounded with quotes. Special
406 characters may be escaped using <tt>"\xx"</tt> where <tt>xx</tt> is the
407 ASCII code for the character in hexadecimal. In this way, any character
408 can be used in a name value, even quotes themselves.</li>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]409
Reid Spencer2c452282007-08-07 14:34:28 +0000[diff] [blame]410 <li>Unnamed values are represented as an unsigned numeric value with their
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]411 prefix. For example, <tt>%12</tt>, <tt>@2</tt>, <tt>%44</tt>.</li>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]412
Reid Spencercc16dc32004-12-09 18:02:53 +0000[diff] [blame]413 <li>Constants, which are described in a <a href="#constants">section about
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]414 constants</a>, below.</li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]415</ol>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]416
Reid Spencer2c452282007-08-07 14:34:28 +0000[diff] [blame]417<p>LLVM requires that values start with a prefix for two reasons: Compilers
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]418 don't need to worry about name clashes with reserved words, and the set of
419 reserved words may be expanded in the future without penalty. Additionally,
420 unnamed identifiers allow a compiler to quickly come up with a temporary
421 variable without having to avoid symbol table conflicts.</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]422
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]423<p>Reserved words in LLVM are very similar to reserved words in other
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]424 languages. There are keywords for different opcodes
425 ('<tt><a href="#i_add">add</a></tt>',
426 '<tt><a href="#i_bitcast">bitcast</a></tt>',
427 '<tt><a href="#i_ret">ret</a></tt>', etc...), for primitive type names
428 ('<tt><a href="#t_void">void</a></tt>',
429 '<tt><a href="#t_primitive">i32</a></tt>', etc...), and others. These
430 reserved words cannot conflict with variable names, because none of them
431 start with a prefix character (<tt>'%'</tt> or <tt>'@'</tt>).</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]432
433<p>Here is an example of LLVM code to multiply the integer variable
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]434 '<tt>%X</tt>' by 8:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]435
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]436<p>The easy way:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]437
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]438<pre class="doc_code">
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]439%result = <a href="#i_mul">mul</a> i32 %X, 8
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]440</pre>
441
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]442<p>After strength reduction:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]443
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]444<pre class="doc_code">
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]445%result = <a href="#i_shl">shl</a> i32 %X, i8 3
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]446</pre>
447
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]448<p>And the hard way:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]449
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]450<pre class="doc_code">
Gabor Greifec58f752009-10-28 13:05:07 +0000[diff] [blame]451%0 = <a href="#i_add">add</a> i32 %X, %X <i>; yields {i32}:%0</i>
452%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]453%result = <a href="#i_add">add</a> i32 %1, %1
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]454</pre>
455
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]456<p>This last way of multiplying <tt>%X</tt> by 8 illustrates several important
457 lexical features of LLVM:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]458
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]459<ol>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]460 <li>Comments are delimited with a '<tt>;</tt>' and go until the end of
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]461 line.</li>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]462
463 <li>Unnamed temporaries are created when the result of a computation is not
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]464 assigned to a named value.</li>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]465
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]466 <li>Unnamed temporaries are numbered sequentially</li>
467</ol>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]468
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]469<p>It also shows a convention that we follow in this document. When
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]470 demonstrating instructions, we will follow an instruction with a comment that
471 defines the type and name of value produced. Comments are shown in italic
472 text.</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]473
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]474</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]475
476<!-- *********************************************************************** -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]477<h2><a name="highlevel">High Level Structure</a></h2>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]478<!-- *********************************************************************** -->
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]479<div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]480<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]481<h3>
482 <a name="modulestructure">Module Structure</a>
483</h3>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]484
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]485<div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]486
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]487<p>LLVM programs are composed of "Module"s, each of which is a translation unit
488 of the input programs. Each module consists of functions, global variables,
489 and symbol table entries. Modules may be combined together with the LLVM
490 linker, which merges function (and global variable) definitions, resolves
491 forward declarations, and merges symbol table entries. Here is an example of
492 the "hello world" module:</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]493
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]494<pre class="doc_code">
Chris Lattner63e4ccb2010-08-17 17:13:42 +0000[diff] [blame]495<i>; Declare the string constant as a global constant.</i>&nbsp;
Nick Lewyckydb9cd762011-01-29 01:09:53 +0000[diff] [blame]496<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]497
Chris Lattner63e4ccb2010-08-17 17:13:42 +0000[diff] [blame]498<i>; External declaration of the puts function</i>&nbsp;
499<a href="#functionstructure">declare</a> i32 @puts(i8*) <i>; i32 (i8*)* </i>&nbsp;
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]500
501<i>; Definition of main function</i>
Chris Lattner63e4ccb2010-08-17 17:13:42 +0000[diff] [blame]502define i32 @main() { <i>; i32()* </i>&nbsp;
503 <i>; Convert [13 x i8]* to i8 *...</i>&nbsp;
504 %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]505
Chris Lattner63e4ccb2010-08-17 17:13:42 +0000[diff] [blame]506 <i>; Call puts function to write out the string to stdout.</i>&nbsp;
507 <a href="#i_call">call</a> i32 @puts(i8* %cast210) <i>; i32</i>&nbsp;
508 <a href="#i_ret">ret</a> i32 0&nbsp;
509}
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]510
511<i>; Named metadata</i>
512!1 = metadata !{i32 41}
513!foo = !{!1, null}
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]514</pre>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]515
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]516<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]517 "<tt>.LC0</tt>", an external declaration of the "<tt>puts</tt>" function,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]518 a <a href="#functionstructure">function definition</a> for
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]519 "<tt>main</tt>" and <a href="#namedmetadatastructure">named metadata</a>
520 "<tt>foo"</tt>.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]521
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]522<p>In general, a module is made up of a list of global values, where both
523 functions and global variables are global values. Global values are
524 represented by a pointer to a memory location (in this case, a pointer to an
525 array of char, and a pointer to a function), and have one of the
526 following <a href="#linkage">linkage types</a>.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]527
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]528</div>
529
530<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]531<h3>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]532 <a name="linkage">Linkage Types</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]533</h3>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]534
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]535<div>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]536
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]537<p>All Global Variables and Functions have one of the following types of
538 linkage:</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]539
540<dl>
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]541 <dt><tt><b><a name="linkage_private">private</a></b></tt></dt>
Bill Wendling5e721d72010-07-01 21:55:59 +0000[diff] [blame]542 <dd>Global values with "<tt>private</tt>" linkage are only directly accessible
543 by objects in the current module. In particular, linking code into a
544 module with an private global value may cause the private to be renamed as
545 necessary to avoid collisions. Because the symbol is private to the
546 module, all references can be updated. This doesn't show up in any symbol
547 table in the object file.</dd>
Rafael Espindolabb46f522009-01-15 20:18:42 +0000[diff] [blame]548
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]549 <dt><tt><b><a name="linkage_linker_private">linker_private</a></b></tt></dt>
Bill Wendling5e721d72010-07-01 21:55:59 +0000[diff] [blame]550 <dd>Similar to <tt>private</tt>, but the symbol is passed through the
551 assembler and evaluated by the linker. Unlike normal strong symbols, they
552 are removed by the linker from the final linked image (executable or
553 dynamic library).</dd>
554
555 <dt><tt><b><a name="linkage_linker_private_weak">linker_private_weak</a></b></tt></dt>
556 <dd>Similar to "<tt>linker_private</tt>", but the symbol is weak. Note that
557 <tt>linker_private_weak</tt> symbols are subject to coalescing by the
558 linker. The symbols are removed by the linker from the final linked image
559 (executable or dynamic library).</dd>
Bill Wendling3d10a5a2009-07-20 01:03:30 +0000[diff] [blame]560
Bill Wendling55ae5152010-08-20 22:05:50 +0000[diff] [blame]561 <dt><tt><b><a name="linkage_linker_private_weak_def_auto">linker_private_weak_def_auto</a></b></tt></dt>
562 <dd>Similar to "<tt>linker_private_weak</tt>", but it's known that the address
563 of the object is not taken. For instance, functions that had an inline
564 definition, but the compiler decided not to inline it. Note,
565 unlike <tt>linker_private</tt> and <tt>linker_private_weak</tt>,
566 <tt>linker_private_weak_def_auto</tt> may have only <tt>default</tt>
567 visibility. The symbols are removed by the linker from the final linked
568 image (executable or dynamic library).</dd>
569
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]570 <dt><tt><b><a name="linkage_internal">internal</a></b></tt></dt>
Bill Wendling07d31772010-06-29 22:34:52 +0000[diff] [blame]571 <dd>Similar to private, but the value shows as a local symbol
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]572 (<tt>STB_LOCAL</tt> in the case of ELF) in the object file. This
573 corresponds to the notion of the '<tt>static</tt>' keyword in C.</dd>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]574
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]575 <dt><tt><b><a name="linkage_available_externally">available_externally</a></b></tt></dt>
Chris Lattner266c7bb2009-04-13 05:44:34 +0000[diff] [blame]576 <dd>Globals with "<tt>available_externally</tt>" linkage are never emitted
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]577 into the object file corresponding to the LLVM module. They exist to
578 allow inlining and other optimizations to take place given knowledge of
579 the definition of the global, which is known to be somewhere outside the
580 module. Globals with <tt>available_externally</tt> linkage are allowed to
581 be discarded at will, and are otherwise the same as <tt>linkonce_odr</tt>.
582 This linkage type is only allowed on definitions, not declarations.</dd>
Chris Lattner266c7bb2009-04-13 05:44:34 +0000[diff] [blame]583
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]584 <dt><tt><b><a name="linkage_linkonce">linkonce</a></b></tt></dt>
Chris Lattner4887bd82007-01-14 06:51:48 +0000[diff] [blame]585 <dd>Globals with "<tt>linkonce</tt>" linkage are merged with other globals of
Chris Lattner873187c2010-01-09 19:15:14 +0000[diff] [blame]586 the same name when linkage occurs. This can be used to implement
587 some forms of inline functions, templates, or other code which must be
588 generated in each translation unit that uses it, but where the body may
589 be overridden with a more definitive definition later. Unreferenced
590 <tt>linkonce</tt> globals are allowed to be discarded. Note that
591 <tt>linkonce</tt> linkage does not actually allow the optimizer to
592 inline the body of this function into callers because it doesn't know if
593 this definition of the function is the definitive definition within the
594 program or whether it will be overridden by a stronger definition.
595 To enable inlining and other optimizations, use "<tt>linkonce_odr</tt>"
596 linkage.</dd>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]597
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]598 <dt><tt><b><a name="linkage_weak">weak</a></b></tt></dt>
Chris Lattner26d054d2009-08-05 05:21:07 +0000[diff] [blame]599 <dd>"<tt>weak</tt>" linkage has the same merging semantics as
600 <tt>linkonce</tt> linkage, except that unreferenced globals with
601 <tt>weak</tt> linkage may not be discarded. This is used for globals that
602 are declared "weak" in C source code.</dd>
603
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]604 <dt><tt><b><a name="linkage_common">common</a></b></tt></dt>
Chris Lattner26d054d2009-08-05 05:21:07 +0000[diff] [blame]605 <dd>"<tt>common</tt>" linkage is most similar to "<tt>weak</tt>" linkage, but
606 they are used for tentative definitions in C, such as "<tt>int X;</tt>" at
607 global scope.
608 Symbols with "<tt>common</tt>" linkage are merged in the same way as
609 <tt>weak symbols</tt>, and they may not be deleted if unreferenced.
Chris Lattnercd81f5d2009-08-05 05:41:44 +0000[diff] [blame]610 <tt>common</tt> symbols may not have an explicit section,
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]611 must have a zero initializer, and may not be marked '<a
Chris Lattnercd81f5d2009-08-05 05:41:44 +0000[diff] [blame]612 href="#globalvars"><tt>constant</tt></a>'. Functions and aliases may not
613 have common linkage.</dd>
Chris Lattner26d054d2009-08-05 05:21:07 +0000[diff] [blame]614
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]615
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]616 <dt><tt><b><a name="linkage_appending">appending</a></b></tt></dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]617 <dd>"<tt>appending</tt>" linkage may only be applied to global variables of
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]618 pointer to array type. When two global variables with appending linkage
619 are linked together, the two global arrays are appended together. This is
620 the LLVM, typesafe, equivalent of having the system linker append together
621 "sections" with identical names when .o files are linked.</dd>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]622
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]623 <dt><tt><b><a name="linkage_externweak">extern_weak</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]624 <dd>The semantics of this linkage follow the ELF object file model: the symbol
625 is weak until linked, if not linked, the symbol becomes null instead of
626 being an undefined reference.</dd>
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]627
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]628 <dt><tt><b><a name="linkage_linkonce_odr">linkonce_odr</a></b></tt></dt>
629 <dt><tt><b><a name="linkage_weak_odr">weak_odr</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]630 <dd>Some languages allow differing globals to be merged, such as two functions
631 with different semantics. Other languages, such as <tt>C++</tt>, ensure
Bill Wendling5e721d72010-07-01 21:55:59 +0000[diff] [blame]632 that only equivalent globals are ever merged (the "one definition rule"
633 &mdash; "ODR"). Such languages can use the <tt>linkonce_odr</tt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]634 and <tt>weak_odr</tt> linkage types to indicate that the global will only
635 be merged with equivalent globals. These linkage types are otherwise the
636 same as their non-<tt>odr</tt> versions.</dd>
Duncan Sands667d4b82009-03-07 15:45:40 +0000[diff] [blame]637
Bill Wendling5c3a9f72011-11-04 20:40:41 +0000[diff] [blame]638 <dt><tt><b><a name="linkage_external">external</a></b></tt></dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]639 <dd>If none of the above identifiers are used, the global is externally
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]640 visible, meaning that it participates in linkage and can be used to
641 resolve external symbol references.</dd>
Reid Spencerc8910842007-04-11 23:49:50 +0000[diff] [blame]642</dl>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]643
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]644<p>The next two types of linkage are targeted for Microsoft Windows platform
645 only. They are designed to support importing (exporting) symbols from (to)
646 DLLs (Dynamic Link Libraries).</p>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]647
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]648<dl>
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]649 <dt><tt><b><a name="linkage_dllimport">dllimport</a></b></tt></dt>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]650 <dd>"<tt>dllimport</tt>" linkage causes the compiler to reference a function
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]651 or variable via a global pointer to a pointer that is set up by the DLL
652 exporting the symbol. On Microsoft Windows targets, the pointer name is
653 formed by combining <code>__imp_</code> and the function or variable
654 name.</dd>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]655
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]656 <dt><tt><b><a name="linkage_dllexport">dllexport</a></b></tt></dt>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]657 <dd>"<tt>dllexport</tt>" linkage causes the compiler to provide a global
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]658 pointer to a pointer in a DLL, so that it can be referenced with the
659 <tt>dllimport</tt> attribute. On Microsoft Windows targets, the pointer
660 name is formed by combining <code>__imp_</code> and the function or
661 variable name.</dd>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]662</dl>
663
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]664<p>For example, since the "<tt>.LC0</tt>" variable is defined to be internal, if
665 another module defined a "<tt>.LC0</tt>" variable and was linked with this
666 one, one of the two would be renamed, preventing a collision. Since
667 "<tt>main</tt>" and "<tt>puts</tt>" are external (i.e., lacking any linkage
668 declarations), they are accessible outside of the current module.</p>
669
670<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]671 other than <tt>external</tt>, <tt>dllimport</tt>
672 or <tt>extern_weak</tt>.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]673
Duncan Sands667d4b82009-03-07 15:45:40 +0000[diff] [blame]674<p>Aliases can have only <tt>external</tt>, <tt>internal</tt>, <tt>weak</tt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]675 or <tt>weak_odr</tt> linkages.</p>
676
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]677</div>
678
679<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]680<h3>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]681 <a name="callingconv">Calling Conventions</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]682</h3>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]683
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]684<div>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]685
686<p>LLVM <a href="#functionstructure">functions</a>, <a href="#i_call">calls</a>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]687 and <a href="#i_invoke">invokes</a> can all have an optional calling
688 convention specified for the call. The calling convention of any pair of
689 dynamic caller/callee must match, or the behavior of the program is
690 undefined. The following calling conventions are supported by LLVM, and more
691 may be added in the future:</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]692
693<dl>
694 <dt><b>"<tt>ccc</tt>" - The C calling convention</b>:</dt>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]695 <dd>This calling convention (the default if no other calling convention is
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]696 specified) matches the target C calling conventions. This calling
697 convention supports varargs function calls and tolerates some mismatch in
698 the declared prototype and implemented declaration of the function (as
699 does normal C).</dd>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]700
701 <dt><b>"<tt>fastcc</tt>" - The fast calling convention</b>:</dt>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]702 <dd>This calling convention attempts to make calls as fast as possible
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]703 (e.g. by passing things in registers). This calling convention allows the
704 target to use whatever tricks it wants to produce fast code for the
705 target, without having to conform to an externally specified ABI
Jeffrey Yasskin95fa80a2010-01-09 19:44:16 +0000[diff] [blame]706 (Application Binary Interface).
707 <a href="CodeGenerator.html#tailcallopt">Tail calls can only be optimized
Chris Lattner29689432010-03-11 00:22:57 +0000[diff] [blame]708 when this or the GHC convention is used.</a> This calling convention
709 does not support varargs and requires the prototype of all callees to
710 exactly match the prototype of the function definition.</dd>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]711
712 <dt><b>"<tt>coldcc</tt>" - The cold calling convention</b>:</dt>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]713 <dd>This calling convention attempts to make code in the caller as efficient
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]714 as possible under the assumption that the call is not commonly executed.
715 As such, these calls often preserve all registers so that the call does
716 not break any live ranges in the caller side. This calling convention
717 does not support varargs and requires the prototype of all callees to
718 exactly match the prototype of the function definition.</dd>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]719
Chris Lattner29689432010-03-11 00:22:57 +0000[diff] [blame]720 <dt><b>"<tt>cc <em>10</em></tt>" - GHC convention</b>:</dt>
721 <dd>This calling convention has been implemented specifically for use by the
722 <a href="http://www.haskell.org/ghc">Glasgow Haskell Compiler (GHC)</a>.
723 It passes everything in registers, going to extremes to achieve this by
724 disabling callee save registers. This calling convention should not be
725 used lightly but only for specific situations such as an alternative to
726 the <em>register pinning</em> performance technique often used when
727 implementing functional programming languages.At the moment only X86
728 supports this convention and it has the following limitations:
729 <ul>
730 <li>On <em>X86-32</em> only supports up to 4 bit type parameters. No
731 floating point types are supported.</li>
732 <li>On <em>X86-64</em> only supports up to 10 bit type parameters and
733 6 floating point parameters.</li>
734 </ul>
735 This calling convention supports
736 <a href="CodeGenerator.html#tailcallopt">tail call optimization</a> but
737 requires both the caller and callee are using it.
738 </dd>
739
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame]740 <dt><b>"<tt>cc &lt;<em>n</em>&gt;</tt>" - Numbered convention</b>:</dt>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]741 <dd>Any calling convention may be specified by number, allowing
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]742 target-specific calling conventions to be used. Target specific calling
743 conventions start at 64.</dd>
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame]744</dl>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]745
746<p>More calling conventions can be added/defined on an as-needed basis, to
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]747 support Pascal conventions or any other well-known target-independent
748 convention.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]749
750</div>
751
752<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]753<h3>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]754 <a name="visibility">Visibility Styles</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]755</h3>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]756
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]757<div>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]758
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]759<p>All Global Variables and Functions have one of the following visibility
760 styles:</p>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]761
762<dl>
763 <dt><b>"<tt>default</tt>" - Default style</b>:</dt>
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]764 <dd>On targets that use the ELF object file format, default visibility means
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]765 that the declaration is visible to other modules and, in shared libraries,
766 means that the declared entity may be overridden. On Darwin, default
767 visibility means that the declaration is visible to other modules. Default
768 visibility corresponds to "external linkage" in the language.</dd>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]769
770 <dt><b>"<tt>hidden</tt>" - Hidden style</b>:</dt>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]771 <dd>Two declarations of an object with hidden visibility refer to the same
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]772 object if they are in the same shared object. Usually, hidden visibility
773 indicates that the symbol will not be placed into the dynamic symbol
774 table, so no other module (executable or shared library) can reference it
775 directly.</dd>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]776
Anton Korobeynikov6f9896f2007-04-29 18:35:00 +0000[diff] [blame]777 <dt><b>"<tt>protected</tt>" - Protected style</b>:</dt>
Anton Korobeynikov6f9896f2007-04-29 18:35:00 +0000[diff] [blame]778 <dd>On ELF, protected visibility indicates that the symbol will be placed in
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]779 the dynamic symbol table, but that references within the defining module
780 will bind to the local symbol. That is, the symbol cannot be overridden by
781 another module.</dd>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]782</dl>
783
784</div>
785
786<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]787<h3>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]788 <a name="namedtypes">Named Types</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]789</h3>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]790
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]791<div>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]792
793<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]794 it easier to read the IR and make the IR more condensed (particularly when
795 recursive types are involved). An example of a name specification is:</p>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]796
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]797<pre class="doc_code">
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]798%mytype = type { %mytype*, i32 }
799</pre>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]800
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]801<p>You may give a name to any <a href="#typesystem">type</a> except
Chris Lattnerdc65f222010-08-17 23:26:04 +0000[diff] [blame]802 "<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]803 is expected with the syntax "%mytype".</p>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]804
805<p>Note that type names are aliases for the structural type that they indicate,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]806 and that you can therefore specify multiple names for the same type. This
807 often leads to confusing behavior when dumping out a .ll file. Since LLVM IR
808 uses structural typing, the name is not part of the type. When printing out
809 LLVM IR, the printer will pick <em>one name</em> to render all types of a
810 particular shape. This means that if you have code where two different
811 source types end up having the same LLVM type, that the dumper will sometimes
812 print the "wrong" or unexpected type. This is an important design point and
813 isn't going to change.</p>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]814
815</div>
816
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]817<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]818<h3>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]819 <a name="globalvars">Global Variables</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]820</h3>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]821
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]822<div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]823
Chris Lattner3689a342005-02-12 19:30:21 +0000[diff] [blame]824<p>Global variables define regions of memory allocated at compilation time
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]825 instead of run-time. Global variables may optionally be initialized, may
826 have an explicit section to be placed in, and may have an optional explicit
827 alignment specified. A variable may be defined as "thread_local", which
828 means that it will not be shared by threads (each thread will have a
829 separated copy of the variable). A variable may be defined as a global
830 "constant," which indicates that the contents of the variable
831 will <b>never</b> be modified (enabling better optimization, allowing the
832 global data to be placed in the read-only section of an executable, etc).
833 Note that variables that need runtime initialization cannot be marked
834 "constant" as there is a store to the variable.</p>
Chris Lattner3689a342005-02-12 19:30:21 +0000[diff] [blame]835
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]836<p>LLVM explicitly allows <em>declarations</em> of global variables to be marked
837 constant, even if the final definition of the global is not. This capability
838 can be used to enable slightly better optimization of the program, but
839 requires the language definition to guarantee that optimizations based on the
840 'constantness' are valid for the translation units that do not include the
841 definition.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]842
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]843<p>As SSA values, global variables define pointer values that are in scope
844 (i.e. they dominate) all basic blocks in the program. Global variables
845 always define a pointer to their "content" type because they describe a
846 region of memory, and all memory objects in LLVM are accessed through
847 pointers.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]848
Rafael Espindolabea46262011-01-08 16:42:36 +0000[diff] [blame]849<p>Global variables can be marked with <tt>unnamed_addr</tt> which indicates
850 that the address is not significant, only the content. Constants marked
Rafael Espindolaa5eaa862011-01-15 08:20:57 +0000[diff] [blame]851 like this can be merged with other constants if they have the same
852 initializer. Note that a constant with significant address <em>can</em>
853 be merged with a <tt>unnamed_addr</tt> constant, the result being a
854 constant whose address is significant.</p>
Rafael Espindolabea46262011-01-08 16:42:36 +0000[diff] [blame]855
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]856<p>A global variable may be declared to reside in a target-specific numbered
857 address space. For targets that support them, address spaces may affect how
858 optimizations are performed and/or what target instructions are used to
859 access the variable. The default address space is zero. The address space
860 qualifier must precede any other attributes.</p>
Christopher Lamb284d9922007-12-11 09:31:00 +0000[diff] [blame]861
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]862<p>LLVM allows an explicit section to be specified for globals. If the target
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]863 supports it, it will emit globals to the section specified.</p>
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]864
Chris Lattnerce99fa92010-04-28 00:13:42 +0000[diff] [blame]865<p>An explicit alignment may be specified for a global, which must be a power
866 of 2. If not present, or if the alignment is set to zero, the alignment of
867 the global is set by the target to whatever it feels convenient. If an
868 explicit alignment is specified, the global is forced to have exactly that
Chris Lattner2d4b8ee2010-04-28 00:31:12 +0000[diff] [blame]869 alignment. Targets and optimizers are not allowed to over-align the global
870 if the global has an assigned section. In this case, the extra alignment
871 could be observable: for example, code could assume that the globals are
872 densely packed in their section and try to iterate over them as an array,
873 alignment padding would break this iteration.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]874
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]875<p>For example, the following defines a global in a numbered address space with
876 an initializer, section, and alignment:</p>
Chris Lattner68027ea2007-01-14 00:27:09 +0000[diff] [blame]877
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]878<pre class="doc_code">
Dan Gohman398873c2009-01-11 00:40:00 +0000[diff] [blame]879@G = addrspace(5) constant float 1.0, section "foo", align 4
Chris Lattner68027ea2007-01-14 00:27:09 +0000[diff] [blame]880</pre>
881
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]882</div>
883
884
885<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]886<h3>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]887 <a name="functionstructure">Functions</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]888</h3>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]889
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]890<div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]891
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]892<p>LLVM function definitions consist of the "<tt>define</tt>" keyword, an
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]893 optional <a href="#linkage">linkage type</a>, an optional
894 <a href="#visibility">visibility style</a>, an optional
Rafael Espindolabea46262011-01-08 16:42:36 +0000[diff] [blame]895 <a href="#callingconv">calling convention</a>,
896 an optional <tt>unnamed_addr</tt> attribute, a return type, an optional
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]897 <a href="#paramattrs">parameter attribute</a> for the return type, a function
898 name, a (possibly empty) argument list (each with optional
899 <a href="#paramattrs">parameter attributes</a>), optional
900 <a href="#fnattrs">function attributes</a>, an optional section, an optional
901 alignment, an optional <a href="#gc">garbage collector name</a>, an opening
902 curly brace, a list of basic blocks, and a closing curly brace.</p>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]903
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]904<p>LLVM function declarations consist of the "<tt>declare</tt>" keyword, an
905 optional <a href="#linkage">linkage type</a>, an optional
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]906 <a href="#visibility">visibility style</a>, an optional
Rafael Espindolabea46262011-01-08 16:42:36 +0000[diff] [blame]907 <a href="#callingconv">calling convention</a>,
908 an optional <tt>unnamed_addr</tt> attribute, a return type, an optional
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]909 <a href="#paramattrs">parameter attribute</a> for the return type, a function
910 name, a possibly empty list of arguments, an optional alignment, and an
911 optional <a href="#gc">garbage collector name</a>.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]912
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]913<p>A function definition contains a list of basic blocks, forming the CFG
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]914 (Control Flow Graph) for the function. Each basic block may optionally start
915 with a label (giving the basic block a symbol table entry), contains a list
916 of instructions, and ends with a <a href="#terminators">terminator</a>
917 instruction (such as a branch or function return).</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]918
Chris Lattner4a3c9012007-06-08 16:52:14 +0000[diff] [blame]919<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]920 executed on entrance to the function, and it is not allowed to have
921 predecessor basic blocks (i.e. there can not be any branches to the entry
922 block of a function). Because the block can have no predecessors, it also
923 cannot have any <a href="#i_phi">PHI nodes</a>.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]924
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]925<p>LLVM allows an explicit section to be specified for functions. If the target
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]926 supports it, it will emit functions to the section specified.</p>
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]927
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]928<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]929 the alignment is set to zero, the alignment of the function is set by the
930 target to whatever it feels convenient. If an explicit alignment is
931 specified, the function is forced to have at least that much alignment. All
932 alignments must be a power of 2.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]933
Rafael Espindolabea46262011-01-08 16:42:36 +0000[diff] [blame]934<p>If the <tt>unnamed_addr</tt> attribute is given, the address is know to not
Bill Wendling5c3a9f72011-11-04 20:40:41 +0000[diff] [blame]935 be significant and two identical functions can be merged.</p>
Rafael Espindolabea46262011-01-08 16:42:36 +0000[diff] [blame]936
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]937<h5>Syntax:</h5>
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]938<pre class="doc_code">
Chris Lattner50ad45c2008-10-13 16:55:18 +0000[diff] [blame]939define [<a href="#linkage">linkage</a>] [<a href="#visibility">visibility</a>]
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]940 [<a href="#callingconv">cconv</a>] [<a href="#paramattrs">ret attrs</a>]
941 &lt;ResultType&gt; @&lt;FunctionName&gt; ([argument list])
942 [<a href="#fnattrs">fn Attrs</a>] [section "name"] [align N]
943 [<a href="#gc">gc</a>] { ... }
944</pre>
Devang Patel307e8ab2008-10-07 17:48:33 +0000[diff] [blame]945
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]946</div>
947
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]948<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]949<h3>
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]950 <a name="aliasstructure">Aliases</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]951</h3>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]952
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]953<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]954
955<p>Aliases act as "second name" for the aliasee value (which can be either
956 function, global variable, another alias or bitcast of global value). Aliases
957 may have an optional <a href="#linkage">linkage type</a>, and an
958 optional <a href="#visibility">visibility style</a>.</p>
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]959
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]960<h5>Syntax:</h5>
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]961<pre class="doc_code">
Duncan Sands0b23ac12008-09-12 20:48:21 +0000[diff] [blame]962@&lt;Name&gt; = alias [Linkage] [Visibility] &lt;AliaseeTy&gt; @&lt;Aliasee&gt;
Bill Wendlingaac388b2007-05-29 09:42:13 +0000[diff] [blame]963</pre>
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]964
965</div>
966
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]967<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]968<h3>
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]969 <a name="namedmetadatastructure">Named Metadata</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]970</h3>
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]971
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]972<div>
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]973
Chris Lattnere6a5ddd2010-01-15 21:50:19 +0000[diff] [blame]974<p>Named metadata is a collection of metadata. <a href="#metadata">Metadata
Dan Gohman872814a2010-07-21 18:54:18 +0000[diff] [blame]975 nodes</a> (but not metadata strings) are the only valid operands for
Chris Lattnere6a5ddd2010-01-15 21:50:19 +0000[diff] [blame]976 a named metadata.</p>
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]977
978<h5>Syntax:</h5>
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]979<pre class="doc_code">
Dan Gohman872814a2010-07-21 18:54:18 +0000[diff] [blame]980; Some unnamed metadata nodes, which are referenced by the named metadata.
981!0 = metadata !{metadata !"zero"}
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]982!1 = metadata !{metadata !"one"}
Dan Gohman872814a2010-07-21 18:54:18 +0000[diff] [blame]983!2 = metadata !{metadata !"two"}
Dan Gohman1005bc52010-07-13 19:48:13 +0000[diff] [blame]984; A named metadata.
Dan Gohman872814a2010-07-21 18:54:18 +0000[diff] [blame]985!name = !{!0, !1, !2}
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]986</pre>
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]987
988</div>
989
990<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]991<h3>
992 <a name="paramattrs">Parameter Attributes</a>
993</h3>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]994
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]995<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]996
997<p>The return type and each parameter of a function type may have a set of
998 <i>parameter attributes</i> associated with them. Parameter attributes are
999 used to communicate additional information about the result or parameters of
1000 a function. Parameter attributes are considered to be part of the function,
1001 not of the function type, so functions with different parameter attributes
1002 can have the same function type.</p>
1003
1004<p>Parameter attributes are simple keywords that follow the type specified. If
1005 multiple parameter attributes are needed, they are space separated. For
1006 example:</p>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1007
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]1008<pre class="doc_code">
Nick Lewyckyb6a7d252009-02-15 23:06:14 +0000[diff] [blame]1009declare i32 @printf(i8* noalias nocapture, ...)
Chris Lattner66d922c2008-10-04 18:33:34 +0000[diff] [blame]1010declare i32 @atoi(i8 zeroext)
1011declare signext i8 @returns_signed_char()
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1012</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1013
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1014<p>Note that any attributes for the function result (<tt>nounwind</tt>,
1015 <tt>readonly</tt>) come immediately after the argument list.</p>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1016
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1017<p>Currently, only the following parameter attributes are defined:</p>
Chris Lattner47507de2008-01-11 06:20:47 +0000[diff] [blame]1018
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1019<dl>
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1020 <dt><tt><b>zeroext</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1021 <dd>This indicates to the code generator that the parameter or return value
Cameron Zwarichebe81732011-03-16 22:20:18 +0000[diff] [blame]1022 should be zero-extended to the extent required by the target's ABI (which
1023 is usually 32-bits, but is 8-bits for a i1 on x86-64) by the caller (for a
1024 parameter) or the callee (for a return value).</dd>
Chris Lattner47507de2008-01-11 06:20:47 +0000[diff] [blame]1025
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1026 <dt><tt><b>signext</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1027 <dd>This indicates to the code generator that the parameter or return value
Cameron Zwarich9e69ff92011-03-17 14:21:58 +0000[diff] [blame]1028 should be sign-extended to the extent required by the target's ABI (which
1029 is usually 32-bits) by the caller (for a parameter) or the callee (for a
1030 return value).</dd>
Chris Lattner47507de2008-01-11 06:20:47 +0000[diff] [blame]1031
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1032 <dt><tt><b>inreg</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1033 <dd>This indicates that this parameter or return value should be treated in a
1034 special target-dependent fashion during while emitting code for a function
1035 call or return (usually, by putting it in a register as opposed to memory,
1036 though some targets use it to distinguish between two different kinds of
1037 registers). Use of this attribute is target-specific.</dd>
Chris Lattner47507de2008-01-11 06:20:47 +0000[diff] [blame]1038
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1039 <dt><tt><b><a name="byval">byval</a></b></tt></dt>
Chris Lattnera6fd81d2010-11-20 23:49:06 +0000[diff] [blame]1040 <dd><p>This indicates that the pointer parameter should really be passed by
1041 value to the function. The attribute implies that a hidden copy of the
1042 pointee
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1043 is made between the caller and the callee, so the callee is unable to
1044 modify the value in the callee. This attribute is only valid on LLVM
1045 pointer arguments. It is generally used to pass structs and arrays by
1046 value, but is also valid on pointers to scalars. The copy is considered
1047 to belong to the caller not the callee (for example,
1048 <tt><a href="#readonly">readonly</a></tt> functions should not write to
1049 <tt>byval</tt> parameters). This is not a valid attribute for return
Chris Lattnera6fd81d2010-11-20 23:49:06 +0000[diff] [blame]1050 values.</p>
1051
1052 <p>The byval attribute also supports specifying an alignment with
1053 the align attribute. It indicates the alignment of the stack slot to
1054 form and the known alignment of the pointer specified to the call site. If
1055 the alignment is not specified, then the code generator makes a
1056 target-specific assumption.</p></dd>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1057
Dan Gohmanff235352010-07-02 23:18:08 +0000[diff] [blame]1058 <dt><tt><b><a name="sret">sret</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1059 <dd>This indicates that the pointer parameter specifies the address of a
1060 structure that is the return value of the function in the source program.
1061 This pointer must be guaranteed by the caller to be valid: loads and
1062 stores to the structure may be assumed by the callee to not to trap. This
1063 may only be applied to the first parameter. This is not a valid attribute
1064 for return values. </dd>
1065
Dan Gohmanff235352010-07-02 23:18:08 +0000[diff] [blame]1066 <dt><tt><b><a name="noalias">noalias</a></b></tt></dt>
Dan Gohman1e109622010-07-02 18:41:32 +0000[diff] [blame]1067 <dd>This indicates that pointer values
1068 <a href="#pointeraliasing"><i>based</i></a> on the argument or return
Dan Gohmanefca7f92010-07-02 23:46:54 +0000[diff] [blame]1069 value do not alias pointer values which are not <i>based</i> on it,
1070 ignoring certain "irrelevant" dependencies.
1071 For a call to the parent function, dependencies between memory
1072 references from before or after the call and from those during the call
1073 are "irrelevant" to the <tt>noalias</tt> keyword for the arguments and
1074 return value used in that call.
Dan Gohman1e109622010-07-02 18:41:32 +0000[diff] [blame]1075 The caller shares the responsibility with the callee for ensuring that
1076 these requirements are met.
1077 For further details, please see the discussion of the NoAlias response in
Dan Gohmanff70fe42010-07-06 15:26:33 +0000[diff] [blame]1078 <a href="AliasAnalysis.html#MustMayNo">alias analysis</a>.<br>
1079<br>
John McCall191d4ee2010-07-06 21:07:14 +0000[diff] [blame]1080 Note that this definition of <tt>noalias</tt> is intentionally
1081 similar to the definition of <tt>restrict</tt> in C99 for function
Chris Lattner211244a2010-07-06 20:51:35 +0000[diff] [blame]1082 arguments, though it is slightly weaker.
Dan Gohmanff70fe42010-07-06 15:26:33 +0000[diff] [blame]1083<br>
1084 For function return values, C99's <tt>restrict</tt> is not meaningful,
1085 while LLVM's <tt>noalias</tt> is.
1086 </dd>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1087
Dan Gohmanff235352010-07-02 23:18:08 +0000[diff] [blame]1088 <dt><tt><b><a name="nocapture">nocapture</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1089 <dd>This indicates that the callee does not make any copies of the pointer
1090 that outlive the callee itself. This is not a valid attribute for return
1091 values.</dd>
1092
Dan Gohmanff235352010-07-02 23:18:08 +0000[diff] [blame]1093 <dt><tt><b><a name="nest">nest</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1094 <dd>This indicates that the pointer parameter can be excised using the
1095 <a href="#int_trampoline">trampoline intrinsics</a>. This is not a valid
1096 attribute for return values.</dd>
1097</dl>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1098
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1099</div>
1100
1101<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1102<h3>
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]1103 <a name="gc">Garbage Collector Names</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1104</h3>
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]1105
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1106<div>
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]1107
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1108<p>Each function may specify a garbage collector name, which is simply a
1109 string:</p>
1110
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]1111<pre class="doc_code">
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1112define void @f() gc "name" { ... }
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1113</pre>
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]1114
1115<p>The compiler declares the supported values of <i>name</i>. Specifying a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1116 collector which will cause the compiler to alter its output in order to
1117 support the named garbage collection algorithm.</p>
1118
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]1119</div>
1120
1121<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1122<h3>
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1123 <a name="fnattrs">Function Attributes</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1124</h3>
Devang Patelf8b94812008-09-04 23:05:13 +0000[diff] [blame]1125
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1126<div>
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1127
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1128<p>Function attributes are set to communicate additional information about a
1129 function. Function attributes are considered to be part of the function, not
1130 of the function type, so functions with different parameter attributes can
1131 have the same function type.</p>
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1132
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1133<p>Function attributes are simple keywords that follow the type specified. If
1134 multiple attributes are needed, they are space separated. For example:</p>
Devang Patelf8b94812008-09-04 23:05:13 +0000[diff] [blame]1135
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]1136<pre class="doc_code">
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1137define void @f() noinline { ... }
1138define void @f() alwaysinline { ... }
1139define void @f() alwaysinline optsize { ... }
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1140define void @f() optsize { ... }
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1141</pre>
Devang Patelf8b94812008-09-04 23:05:13 +0000[diff] [blame]1142
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1143<dl>
Charles Davis1e063d12010-02-12 00:31:15 +0000[diff] [blame]1144 <dt><tt><b>alignstack(&lt;<em>n</em>&gt;)</b></tt></dt>
1145 <dd>This attribute indicates that, when emitting the prologue and epilogue,
1146 the backend should forcibly align the stack pointer. Specify the
1147 desired alignment, which must be a power of two, in parentheses.
1148
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1149 <dt><tt><b>alwaysinline</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1150 <dd>This attribute indicates that the inliner should attempt to inline this
1151 function into callers whenever possible, ignoring any active inlining size
1152 threshold for this caller.</dd>
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1153
Dan Gohman129bd562011-06-16 16:03:13 +0000[diff] [blame]1154 <dt><tt><b>nonlazybind</b></tt></dt>
1155 <dd>This attribute suppresses lazy symbol binding for the function. This
1156 may make calls to the function faster, at the cost of extra program
1157 startup time if the function is not called during program startup.</dd>
1158
Jakob Stoklund Olesen570a4a52010-02-06 01:16:28 +0000[diff] [blame]1159 <dt><tt><b>inlinehint</b></tt></dt>
1160 <dd>This attribute indicates that the source code contained a hint that inlining
1161 this function is desirable (such as the "inline" keyword in C/C++). It
1162 is just a hint; it imposes no requirements on the inliner.</dd>
1163
Nick Lewycky76ec37a2010-07-06 18:24:09 +0000[diff] [blame]1164 <dt><tt><b>naked</b></tt></dt>
1165 <dd>This attribute disables prologue / epilogue emission for the function.
1166 This can have very system-specific consequences.</dd>
1167
1168 <dt><tt><b>noimplicitfloat</b></tt></dt>
1169 <dd>This attributes disables implicit floating point instructions.</dd>
1170
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1171 <dt><tt><b>noinline</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1172 <dd>This attribute indicates that the inliner should never inline this
1173 function in any situation. This attribute may not be used together with
1174 the <tt>alwaysinline</tt> attribute.</dd>
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1175
Nick Lewycky76ec37a2010-07-06 18:24:09 +0000[diff] [blame]1176 <dt><tt><b>noredzone</b></tt></dt>
1177 <dd>This attribute indicates that the code generator should not use a red
1178 zone, even if the target-specific ABI normally permits it.</dd>
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1179
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1180 <dt><tt><b>noreturn</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1181 <dd>This function attribute indicates that the function never returns
1182 normally. This produces undefined behavior at runtime if the function
1183 ever does dynamically return.</dd>
Bill Wendling31359ba2008-11-13 01:02:51 +0000[diff] [blame]1184
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1185 <dt><tt><b>nounwind</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1186 <dd>This function attribute indicates that the function never returns with an
1187 unwind or exceptional control flow. If the function does unwind, its
1188 runtime behavior is undefined.</dd>
Bill Wendlingfbaa7ed2008-11-26 19:07:40 +0000[diff] [blame]1189
Nick Lewycky76ec37a2010-07-06 18:24:09 +0000[diff] [blame]1190 <dt><tt><b>optsize</b></tt></dt>
1191 <dd>This attribute suggests that optimization passes and code generator passes
1192 make choices that keep the code size of this function low, and otherwise
1193 do optimizations specifically to reduce code size.</dd>
1194
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1195 <dt><tt><b>readnone</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1196 <dd>This attribute indicates that the function computes its result (or decides
1197 to unwind an exception) based strictly on its arguments, without
1198 dereferencing any pointer arguments or otherwise accessing any mutable
1199 state (e.g. memory, control registers, etc) visible to caller functions.
1200 It does not write through any pointer arguments
1201 (including <tt><a href="#byval">byval</a></tt> arguments) and never
1202 changes any state visible to callers. This means that it cannot unwind
1203 exceptions by calling the <tt>C++</tt> exception throwing methods, but
1204 could use the <tt>unwind</tt> instruction.</dd>
Devang Patel5d96fda2009-06-12 19:45:19 +0000[diff] [blame]1205
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1206 <dt><tt><b><a name="readonly">readonly</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1207 <dd>This attribute indicates that the function does not write through any
1208 pointer arguments (including <tt><a href="#byval">byval</a></tt>
1209 arguments) or otherwise modify any state (e.g. memory, control registers,
1210 etc) visible to caller functions. It may dereference pointer arguments
1211 and read state that may be set in the caller. A readonly function always
1212 returns the same value (or unwinds an exception identically) when called
1213 with the same set of arguments and global state. It cannot unwind an
1214 exception by calling the <tt>C++</tt> exception throwing methods, but may
1215 use the <tt>unwind</tt> instruction.</dd>
Anton Korobeynikovc5ec8a72009-07-17 18:07:26 +0000[diff] [blame]1216
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1217 <dt><tt><b><a name="ssp">ssp</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1218 <dd>This attribute indicates that the function should emit a stack smashing
1219 protector. It is in the form of a "canary"&mdash;a random value placed on
1220 the stack before the local variables that's checked upon return from the
1221 function to see if it has been overwritten. A heuristic is used to
1222 determine if a function needs stack protectors or not.<br>
1223<br>
1224 If a function that has an <tt>ssp</tt> attribute is inlined into a
1225 function that doesn't have an <tt>ssp</tt> attribute, then the resulting
1226 function will have an <tt>ssp</tt> attribute.</dd>
1227
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1228 <dt><tt><b>sspreq</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1229 <dd>This attribute indicates that the function should <em>always</em> emit a
1230 stack smashing protector. This overrides
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1231 the <tt><a href="#ssp">ssp</a></tt> function attribute.<br>
1232<br>
1233 If a function that has an <tt>sspreq</tt> attribute is inlined into a
1234 function that doesn't have an <tt>sspreq</tt> attribute or which has
1235 an <tt>ssp</tt> attribute, then the resulting function will have
1236 an <tt>sspreq</tt> attribute.</dd>
Rafael Espindolafbff0ec2011-07-25 15:27:59 +0000[diff] [blame]1237
1238 <dt><tt><b><a name="uwtable">uwtable</a></b></tt></dt>
1239 <dd>This attribute indicates that the ABI being targeted requires that
1240 an unwind table entry be produce for this function even if we can
1241 show that no exceptions passes by it. This is normally the case for
1242 the ELF x86-64 abi, but it can be disabled for some compilation
1243 units.</dd>
1244
Rafael Espindola25456ef2011-10-03 14:45:37 +0000[diff] [blame]1245 <dt><tt><b><a name="returns_twice">returns_twice</a></b></tt></dt>
1246 <dd>This attribute indicates that this function can return
1247 twice. The C <code>setjmp</code> is an example of such a function.
1248 The compiler disables some optimizations (like tail calls) in the caller of
1249 these functions.</dd>
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1250</dl>
1251
Devang Patelf8b94812008-09-04 23:05:13 +0000[diff] [blame]1252</div>
1253
1254<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1255<h3>
Chris Lattner1eeeb0c2006-04-08 04:40:53 +0000[diff] [blame]1256 <a name="moduleasm">Module-Level Inline Assembly</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1257</h3>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1258
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1259<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1260
1261<p>Modules may contain "module-level inline asm" blocks, which corresponds to
1262 the GCC "file scope inline asm" blocks. These blocks are internally
1263 concatenated by LLVM and treated as a single unit, but may be separated in
1264 the <tt>.ll</tt> file if desired. The syntax is very simple:</p>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1265
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]1266<pre class="doc_code">
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1267module asm "inline asm code goes here"
1268module asm "more can go here"
1269</pre>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1270
1271<p>The strings can contain any character by escaping non-printable characters.
1272 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]1273 for the number.</p>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1274
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1275<p>The inline asm code is simply printed to the machine code .s file when
1276 assembly code is generated.</p>
1277
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1278</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1279
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1280<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1281<h3>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1282 <a name="datalayout">Data Layout</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1283</h3>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1284
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1285<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1286
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1287<p>A module may specify a target specific data layout string that specifies how
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1288 data is to be laid out in memory. The syntax for the data layout is
1289 simply:</p>
1290
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]1291<pre class="doc_code">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1292target datalayout = "<i>layout specification</i>"
1293</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1294
1295<p>The <i>layout specification</i> consists of a list of specifications
1296 separated by the minus sign character ('-'). Each specification starts with
1297 a letter and may include other information after the letter to define some
1298 aspect of the data layout. The specifications accepted are as follows:</p>
1299
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1300<dl>
1301 <dt><tt>E</tt></dt>
1302 <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]1303 bits with the most significance have the lowest address location.</dd>
1304
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1305 <dt><tt>e</tt></dt>
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]1306 <dd>Specifies that the target lays out data in little-endian form. That is,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1307 the bits with the least significance have the lowest address
1308 location.</dd>
1309
Lang Hamesbb5b3f32011-10-10 23:42:08 +0000[diff] [blame]1310 <dt><tt>S<i>size</i></tt></dt>
1311 <dd>Specifies the natural alignment of the stack in bits. Alignment promotion
1312 of stack variables is limited to the natural stack alignment to avoid
1313 dynamic stack realignment. The stack alignment must be a multiple of
Lang Hames5f119a62011-10-11 17:50:14 +0000[diff] [blame]1314 8-bits. If omitted, the natural stack alignment defaults to "unspecified",
1315 which does not prevent any alignment promotions.</dd>
Lang Hamesbb5b3f32011-10-10 23:42:08 +0000[diff] [blame]1316
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1317 <dt><tt>p:<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]1318 <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]1319 <i>preferred</i> alignments. All sizes are in bits. Specifying
1320 the <i>pref</i> alignment is optional. If omitted, the
1321 preceding <tt>:</tt> should be omitted too.</dd>
1322
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1323 <dt><tt>i<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1324 <dd>This specifies the alignment for an integer type of a given bit
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1325 <i>size</i>. The value of <i>size</i> must be in the range [1,2^23).</dd>
1326
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1327 <dt><tt>v<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]1328 <dd>This specifies the alignment for a vector type of a given bit
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1329 <i>size</i>.</dd>
1330
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1331 <dt><tt>f<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]1332 <dd>This specifies the alignment for a floating point type of a given bit
Dale Johannesen9d8d2212010-05-28 18:54:47 +0000[diff] [blame]1333 <i>size</i>. Only values of <i>size</i> that are supported by the target
1334 will work. 32 (float) and 64 (double) are supported on all targets;
1335 80 or 128 (different flavors of long double) are also supported on some
1336 targets.
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1337
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1338 <dt><tt>a<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1339 <dd>This specifies the alignment for an aggregate type of a given bit
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1340 <i>size</i>.</dd>
1341
Daniel Dunbar87bde0b2009-06-08 22:17:53 +0000[diff] [blame]1342 <dt><tt>s<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1343 <dd>This specifies the alignment for a stack object of a given bit
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1344 <i>size</i>.</dd>
Chris Lattnere82bdc42009-11-07 09:35:34 +0000[diff] [blame]1345
1346 <dt><tt>n<i>size1</i>:<i>size2</i>:<i>size3</i>...</tt></dt>
1347 <dd>This specifies a set of native integer widths for the target CPU
1348 in bits. For example, it might contain "n32" for 32-bit PowerPC,
1349 "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]1350 this set are considered to support most general arithmetic
Chris Lattnere82bdc42009-11-07 09:35:34 +0000[diff] [blame]1351 operations efficiently.</dd>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1352</dl>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1353
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1354<p>When constructing the data layout for a given target, LLVM starts with a
Dan Gohman1c70c002010-04-28 00:36:01 +0000[diff] [blame]1355 default set of specifications which are then (possibly) overridden by the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1356 specifications in the <tt>datalayout</tt> keyword. The default specifications
1357 are given in this list:</p>
1358
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1359<ul>
1360 <li><tt>E</tt> - big endian</li>
Dan Gohmanfdf2e8c2010-02-23 02:44:03 +0000[diff] [blame]1361 <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]1362 <li><tt>i1:8:8</tt> - i1 is 8-bit (byte) aligned</li>
1363 <li><tt>i8:8:8</tt> - i8 is 8-bit (byte) aligned</li>
1364 <li><tt>i16:16:16</tt> - i16 is 16-bit aligned</li>
1365 <li><tt>i32:32:32</tt> - i32 is 32-bit aligned</li>
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]1366 <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]1367 alignment of 64-bits</li>
1368 <li><tt>f32:32:32</tt> - float is 32-bit aligned</li>
1369 <li><tt>f64:64:64</tt> - double is 64-bit aligned</li>
1370 <li><tt>v64:64:64</tt> - 64-bit vector is 64-bit aligned</li>
1371 <li><tt>v128:128:128</tt> - 128-bit vector is 128-bit aligned</li>
1372 <li><tt>a0:0:1</tt> - aggregates are 8-bit aligned</li>
Daniel Dunbar87bde0b2009-06-08 22:17:53 +0000[diff] [blame]1373 <li><tt>s0:64:64</tt> - stack objects are 64-bit aligned</li>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1374</ul>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1375
1376<p>When LLVM is determining the alignment for a given type, it uses the
1377 following rules:</p>
1378
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1379<ol>
1380 <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]1381 specification is used.</li>
1382
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1383 <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]1384 smallest integer type that is larger than the bitwidth of the sought type
1385 is used. If none of the specifications are larger than the bitwidth then
1386 the the largest integer type is used. For example, given the default
1387 specifications above, the i7 type will use the alignment of i8 (next
1388 largest) while both i65 and i256 will use the alignment of i64 (largest
1389 specified).</li>
1390
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1391 <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]1392 largest vector type that is smaller than the sought vector type will be
1393 used as a fall back. This happens because &lt;128 x double&gt; can be
1394 implemented in terms of 64 &lt;2 x double&gt;, for example.</li>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1395</ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1396
Chris Lattner6509f502011-10-11 23:01:39 +0000[diff] [blame]1397<p>The function of the data layout string may not be what you expect. Notably,
1398 this is not a specification from the frontend of what alignment the code
1399 generator should use.</p>
1400
1401<p>Instead, if specified, the target data layout is required to match what the
1402 ultimate <em>code generator</em> expects. This string is used by the
1403 mid-level optimizers to
1404 improve code, and this only works if it matches what the ultimate code
1405 generator uses. If you would like to generate IR that does not embed this
1406 target-specific detail into the IR, then you don't have to specify the
1407 string. This will disable some optimizations that require precise layout
1408 information, but this also prevents those optimizations from introducing
1409 target specificity into the IR.</p>
1410
1411
1412
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1413</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1414
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1415<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1416<h3>
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1417 <a name="pointeraliasing">Pointer Aliasing Rules</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1418</h3>
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1419
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1420<div>
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1421
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1422<p>Any memory access must be done through a pointer value associated
Andreas Bolka99a82052009-07-27 20:37:10 +0000[diff] [blame]1423with an address range of the memory access, otherwise the behavior
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1424is undefined. Pointer values are associated with address ranges
1425according to the following rules:</p>
1426
1427<ul>
Dan Gohman1e109622010-07-02 18:41:32 +0000[diff] [blame]1428 <li>A pointer value is associated with the addresses associated with
1429 any value it is <i>based</i> on.
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1430 <li>An address of a global variable is associated with the address
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1431 range of the variable's storage.</li>
1432 <li>The result value of an allocation instruction is associated with
1433 the address range of the allocated storage.</li>
1434 <li>A null pointer in the default address-space is associated with
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1435 no address.</li>
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1436 <li>An integer constant other than zero or a pointer value returned
1437 from a function not defined within LLVM may be associated with address
1438 ranges allocated through mechanisms other than those provided by
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1439 LLVM. Such ranges shall not overlap with any ranges of addresses
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1440 allocated by mechanisms provided by LLVM.</li>
Dan Gohman1e109622010-07-02 18:41:32 +0000[diff] [blame]1441</ul>
1442
1443<p>A pointer value is <i>based</i> on another pointer value according
1444 to the following rules:</p>
1445
1446<ul>
1447 <li>A pointer value formed from a
1448 <tt><a href="#i_getelementptr">getelementptr</a></tt> operation
1449 is <i>based</i> on the first operand of the <tt>getelementptr</tt>.</li>
1450 <li>The result value of a
1451 <tt><a href="#i_bitcast">bitcast</a></tt> is <i>based</i> on the operand
1452 of the <tt>bitcast</tt>.</li>
1453 <li>A pointer value formed by an
1454 <tt><a href="#i_inttoptr">inttoptr</a></tt> is <i>based</i> on all
1455 pointer values that contribute (directly or indirectly) to the
1456 computation of the pointer's value.</li>
1457 <li>The "<i>based</i> on" relationship is transitive.</li>
1458</ul>
1459
1460<p>Note that this definition of <i>"based"</i> is intentionally
1461 similar to the definition of <i>"based"</i> in C99, though it is
1462 slightly weaker.</p>
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1463
1464<p>LLVM IR does not associate types with memory. The result type of a
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1465<tt><a href="#i_load">load</a></tt> merely indicates the size and
1466alignment of the memory from which to load, as well as the
Dan Gohmanc22c0f32010-06-17 19:23:50 +0000[diff] [blame]1467interpretation of the value. The first operand type of a
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1468<tt><a href="#i_store">store</a></tt> similarly only indicates the size
1469and alignment of the store.</p>
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1470
1471<p>Consequently, type-based alias analysis, aka TBAA, aka
1472<tt>-fstrict-aliasing</tt>, is not applicable to general unadorned
1473LLVM IR. <a href="#metadata">Metadata</a> may be used to encode
1474additional information which specialized optimization passes may use
1475to implement type-based alias analysis.</p>
1476
1477</div>
1478
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]1479<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1480<h3>
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]1481 <a name="volatile">Volatile Memory Accesses</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1482</h3>
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]1483
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1484<div>
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]1485
1486<p>Certain memory accesses, such as <a href="#i_load"><tt>load</tt></a>s, <a
1487href="#i_store"><tt>store</tt></a>s, and <a
1488href="#int_memcpy"><tt>llvm.memcpy</tt></a>s may be marked <tt>volatile</tt>.
1489The optimizers must not change the number of volatile operations or change their
1490order of execution relative to other volatile operations. The optimizers
1491<i>may</i> change the order of volatile operations relative to non-volatile
1492operations. This is not Java's "volatile" and has no cross-thread
1493synchronization behavior.</p>
1494
1495</div>
1496
Eli Friedman5b60e1b2011-07-20 21:35:53 +0000[diff] [blame]1497<!-- ======================================================================= -->
1498<h3>
1499 <a name="memmodel">Memory Model for Concurrent Operations</a>
1500</h3>
1501
1502<div>
1503
1504<p>The LLVM IR does not define any way to start parallel threads of execution
1505or to register signal handlers. Nonetheless, there are platform-specific
1506ways to create them, and we define LLVM IR's behavior in their presence. This
1507model is inspired by the C++0x memory model.</p>
1508
Eli Friedman234bccd2011-08-22 21:35:27 +0000[diff] [blame]1509<p>For a more informal introduction to this model, see the
1510<a href="Atomics.html">LLVM Atomic Instructions and Concurrency Guide</a>.
1511
Eli Friedman5b60e1b2011-07-20 21:35:53 +0000[diff] [blame]1512<p>We define a <i>happens-before</i> partial order as the least partial order
1513that</p>
1514<ul>
1515 <li>Is a superset of single-thread program order, and</li>
1516 <li>When a <i>synchronizes-with</i> <tt>b</tt>, includes an edge from
1517 <tt>a</tt> to <tt>b</tt>. <i>Synchronizes-with</i> pairs are introduced
1518 by platform-specific techniques, like pthread locks, thread
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1519 creation, thread joining, etc., and by atomic instructions.
1520 (See also <a href="#ordering">Atomic Memory Ordering Constraints</a>).
1521 </li>
Eli Friedman5b60e1b2011-07-20 21:35:53 +0000[diff] [blame]1522</ul>
1523
1524<p>Note that program order does not introduce <i>happens-before</i> edges
1525between a thread and signals executing inside that thread.</p>
1526
1527<p>Every (defined) read operation (load instructions, memcpy, atomic
1528loads/read-modify-writes, etc.) <var>R</var> reads a series of bytes written by
1529(defined) write operations (store instructions, atomic
Eli Friedman118973a2011-07-22 03:04:45 +0000[diff] [blame]1530stores/read-modify-writes, memcpy, etc.). For the purposes of this section,
1531initialized globals are considered to have a write of the initializer which is
1532atomic and happens before any other read or write of the memory in question.
1533For each byte of a read <var>R</var>, <var>R<sub>byte</sub></var> may see
1534any write to the same byte, except:</p>
Eli Friedman5b60e1b2011-07-20 21:35:53 +0000[diff] [blame]1535
1536<ul>
1537 <li>If <var>write<sub>1</sub></var> happens before
1538 <var>write<sub>2</sub></var>, and <var>write<sub>2</sub></var> happens
1539 before <var>R<sub>byte</sub></var>, then <var>R<sub>byte</sub></var>
Eli Friedman118973a2011-07-22 03:04:45 +0000[diff] [blame]1540 does not see <var>write<sub>1</sub></var>.
Bill Wendling0246bb72011-07-31 06:45:03 +0000[diff] [blame]1541 <li>If <var>R<sub>byte</sub></var> happens before
1542 <var>write<sub>3</sub></var>, then <var>R<sub>byte</sub></var> does not
1543 see <var>write<sub>3</sub></var>.
Eli Friedman5b60e1b2011-07-20 21:35:53 +0000[diff] [blame]1544</ul>
1545
1546<p>Given that definition, <var>R<sub>byte</sub></var> is defined as follows:
1547<ul>
Eli Friedman234bccd2011-08-22 21:35:27 +0000[diff] [blame]1548 <li>If <var>R</var> is volatile, the result is target-dependent. (Volatile
1549 is supposed to give guarantees which can support
1550 <code>sig_atomic_t</code> in C/C++, and may be used for accesses to
1551 addresses which do not behave like normal memory. It does not generally
1552 provide cross-thread synchronization.)
1553 <li>Otherwise, if there is no write to the same byte that happens before
Eli Friedman5b60e1b2011-07-20 21:35:53 +0000[diff] [blame]1554 <var>R<sub>byte</sub></var>, <var>R<sub>byte</sub></var> returns
1555 <tt>undef</tt> for that byte.
Eli Friedman118973a2011-07-22 03:04:45 +0000[diff] [blame]1556 <li>Otherwise, if <var>R<sub>byte</sub></var> may see exactly one write,
Eli Friedman5b60e1b2011-07-20 21:35:53 +0000[diff] [blame]1557 <var>R<sub>byte</sub></var> returns the value written by that
1558 write.</li>
Eli Friedman118973a2011-07-22 03:04:45 +0000[diff] [blame]1559 <li>Otherwise, if <var>R</var> is atomic, and all the writes
1560 <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]1561 values written. See the <a href="#ordering">Atomic Memory Ordering
1562 Constraints</a> section for additional constraints on how the choice
1563 is made.
Eli Friedman5b60e1b2011-07-20 21:35:53 +0000[diff] [blame]1564 <li>Otherwise <var>R<sub>byte</sub></var> returns <tt>undef</tt>.</li>
1565</ul>
1566
1567<p><var>R</var> returns the value composed of the series of bytes it read.
1568This implies that some bytes within the value may be <tt>undef</tt>
1569<b>without</b> the entire value being <tt>undef</tt>. Note that this only
1570defines the semantics of the operation; it doesn't mean that targets will
1571emit more than one instruction to read the series of bytes.</p>
1572
1573<p>Note that in cases where none of the atomic intrinsics are used, this model
1574places only one restriction on IR transformations on top of what is required
1575for single-threaded execution: introducing a store to a byte which might not
Eli Friedman101c81d2011-08-02 01:15:34 +0000[diff] [blame]1576otherwise be stored is not allowed in general. (Specifically, in the case
1577where another thread might write to and read from an address, introducing a
1578store can change a load that may see exactly one write into a load that may
1579see multiple writes.)</p>
Eli Friedman5b60e1b2011-07-20 21:35:53 +0000[diff] [blame]1580
1581<!-- FIXME: This model assumes all targets where concurrency is relevant have
1582a byte-size store which doesn't affect adjacent bytes. As far as I can tell,
1583none of the backends currently in the tree fall into this category; however,
1584there might be targets which care. If there are, we want a paragraph
1585like the following:
1586
1587Targets may specify that stores narrower than a certain width are not
1588available; on such a target, for the purposes of this model, treat any
1589non-atomic write with an alignment or width less than the minimum width
1590as if it writes to the relevant surrounding bytes.
1591-->
1592
1593</div>
1594
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1595<!-- ======================================================================= -->
NAKAMURA Takumib5bb29c2011-08-12 06:17:17 +0000[diff] [blame]1596<h3>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1597 <a name="ordering">Atomic Memory Ordering Constraints</a>
NAKAMURA Takumib5bb29c2011-08-12 06:17:17 +0000[diff] [blame]1598</h3>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1599
NAKAMURA Takumib5bb29c2011-08-12 06:17:17 +0000[diff] [blame]1600<div>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1601
1602<p>Atomic instructions (<a href="#i_cmpxchg"><code>cmpxchg</code></a>,
Eli Friedman21006d42011-08-09 23:02:53 +0000[diff] [blame]1603<a href="#i_atomicrmw"><code>atomicrmw</code></a>,
1604<a href="#i_fence"><code>fence</code></a>,
1605<a href="#i_load"><code>atomic load</code></a>, and
Eli Friedman8fa281a2011-08-09 23:26:12 +0000[diff] [blame]1606<a href="#i_store"><code>atomic store</code></a>) take an ordering parameter
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1607that determines which other atomic instructions on the same address they
1608<i>synchronize with</i>. These semantics are borrowed from Java and C++0x,
1609but are somewhat more colloquial. If these descriptions aren't precise enough,
Eli Friedman234bccd2011-08-22 21:35:27 +0000[diff] [blame]1610check those specs (see spec references in the
1611<a href="Atomic.html#introduction">atomics guide</a>).
1612<a href="#i_fence"><code>fence</code></a> instructions
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1613treat these orderings somewhat differently since they don't take an address.
1614See that instruction's documentation for details.</p>
1615
Eli Friedman234bccd2011-08-22 21:35:27 +0000[diff] [blame]1616<p>For a simpler introduction to the ordering constraints, see the
1617<a href="Atomics.html">LLVM Atomic Instructions and Concurrency Guide</a>.</p>
1618
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1619<dl>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1620<dt><code>unordered</code></dt>
1621<dd>The set of values that can be read is governed by the happens-before
1622partial order. A value cannot be read unless some operation wrote it.
1623This is intended to provide a guarantee strong enough to model Java's
1624non-volatile shared variables. This ordering cannot be specified for
1625read-modify-write operations; it is not strong enough to make them atomic
1626in any interesting way.</dd>
1627<dt><code>monotonic</code></dt>
1628<dd>In addition to the guarantees of <code>unordered</code>, there is a single
1629total order for modifications by <code>monotonic</code> operations on each
1630address. All modification orders must be compatible with the happens-before
1631order. There is no guarantee that the modification orders can be combined to
1632a global total order for the whole program (and this often will not be
1633possible). The read in an atomic read-modify-write operation
1634(<a href="#i_cmpxchg"><code>cmpxchg</code></a> and
1635<a href="#i_atomicrmw"><code>atomicrmw</code></a>)
1636reads the value in the modification order immediately before the value it
1637writes. If one atomic read happens before another atomic read of the same
1638address, the later read must see the same value or a later value in the
1639address's modification order. This disallows reordering of
1640<code>monotonic</code> (or stronger) operations on the same address. If an
1641address is written <code>monotonic</code>ally by one thread, and other threads
1642<code>monotonic</code>ally read that address repeatedly, the other threads must
Eli Friedman234bccd2011-08-22 21:35:27 +0000[diff] [blame]1643eventually see the write. This corresponds to the C++0x/C1x
1644<code>memory_order_relaxed</code>.</dd>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1645<dt><code>acquire</code></dt>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1646<dd>In addition to the guarantees of <code>monotonic</code>,
Eli Friedmanc264b2f2011-08-24 20:28:39 +0000[diff] [blame]1647a <i>synchronizes-with</i> edge may be formed with a <code>release</code>
1648operation. This is intended to model C++'s <code>memory_order_acquire</code>.</dd>
1649<dt><code>release</code></dt>
1650<dd>In addition to the guarantees of <code>monotonic</code>, if this operation
1651writes a value which is subsequently read by an <code>acquire</code> operation,
1652it <i>synchronizes-with</i> that operation. (This isn't a complete
1653description; see the C++0x definition of a release sequence.) This corresponds
1654to the C++0x/C1x <code>memory_order_release</code>.</dd>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1655<dt><code>acq_rel</code> (acquire+release)</dt><dd>Acts as both an
Eli Friedman234bccd2011-08-22 21:35:27 +0000[diff] [blame]1656<code>acquire</code> and <code>release</code> operation on its address.
1657This corresponds to the C++0x/C1x <code>memory_order_acq_rel</code>.</dd>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1658<dt><code>seq_cst</code> (sequentially consistent)</dt><dd>
1659<dd>In addition to the guarantees of <code>acq_rel</code>
1660(<code>acquire</code> for an operation which only reads, <code>release</code>
1661for an operation which only writes), there is a global total order on all
1662sequentially-consistent operations on all addresses, which is consistent with
1663the <i>happens-before</i> partial order and with the modification orders of
1664all the affected addresses. Each sequentially-consistent read sees the last
Eli Friedman234bccd2011-08-22 21:35:27 +0000[diff] [blame]1665preceding write to the same address in this global order. This corresponds
1666to the C++0x/C1x <code>memory_order_seq_cst</code> and Java volatile.</dd>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1667</dl>
1668
1669<p id="singlethread">If an atomic operation is marked <code>singlethread</code>,
1670it only <i>synchronizes with</i> or participates in modification and seq_cst
1671total orderings with other operations running in the same thread (for example,
1672in signal handlers).</p>
1673
1674</div>
1675
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1676</div>
1677
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1678<!-- *********************************************************************** -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1679<h2><a name="typesystem">Type System</a></h2>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1680<!-- *********************************************************************** -->
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1681
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1682<div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1683
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1684<p>The LLVM type system is one of the most important features of the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1685 intermediate representation. Being typed enables a number of optimizations
1686 to be performed on the intermediate representation directly, without having
1687 to do extra analyses on the side before the transformation. A strong type
1688 system makes it easier to read the generated code and enables novel analyses
1689 and transformations that are not feasible to perform on normal three address
1690 code representations.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1691
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1692<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1693<h3>
1694 <a name="t_classifications">Type Classifications</a>
1695</h3>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1696
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1697<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1698
1699<p>The types fall into a few useful classifications:</p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1700
1701<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1702 <tbody>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1703 <tr><th>Classification</th><th>Types</th></tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1704 <tr>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1705 <td><a href="#t_integer">integer</a></td>
Reid Spencer2b916312007-05-16 18:44:01 +0000[diff] [blame]1706 <td><tt>i1, i2, i3, ... i8, ... i16, ... i32, ... i64, ... </tt></td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1707 </tr>
1708 <tr>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1709 <td><a href="#t_floating">floating point</a></td>
1710 <td><tt>float, double, x86_fp80, fp128, ppc_fp128</tt></td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1711 </tr>
1712 <tr>
1713 <td><a name="t_firstclass">first class</a></td>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1714 <td><a href="#t_integer">integer</a>,
1715 <a href="#t_floating">floating point</a>,
1716 <a href="#t_pointer">pointer</a>,
Dan Gohman0066db62008-06-18 18:42:13 +0000[diff] [blame]1717 <a href="#t_vector">vector</a>,
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]1718 <a href="#t_struct">structure</a>,
1719 <a href="#t_array">array</a>,
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1720 <a href="#t_label">label</a>,
1721 <a href="#t_metadata">metadata</a>.
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1722 </td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1723 </tr>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1724 <tr>
1725 <td><a href="#t_primitive">primitive</a></td>
1726 <td><a href="#t_label">label</a>,
1727 <a href="#t_void">void</a>,
Tobias Grosser05387292010-12-28 20:29:31 +0000[diff] [blame]1728 <a href="#t_integer">integer</a>,
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1729 <a href="#t_floating">floating point</a>,
Dale Johannesen21fe99b2010-10-01 00:48:59 +0000[diff] [blame]1730 <a href="#t_x86mmx">x86mmx</a>,
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1731 <a href="#t_metadata">metadata</a>.</td>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1732 </tr>
1733 <tr>
1734 <td><a href="#t_derived">derived</a></td>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]1735 <td><a href="#t_array">array</a>,
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1736 <a href="#t_function">function</a>,
1737 <a href="#t_pointer">pointer</a>,
1738 <a href="#t_struct">structure</a>,
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1739 <a href="#t_vector">vector</a>,
1740 <a href="#t_opaque">opaque</a>.
Dan Gohman01ac1012008-10-14 16:32:04 +0000[diff] [blame]1741 </td>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1742 </tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1743 </tbody>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1744</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1745
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1746<p>The <a href="#t_firstclass">first class</a> types are perhaps the most
1747 important. Values of these types are the only ones which can be produced by
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]1748 instructions.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1749
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1750</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1751
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1752<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1753<h3>
1754 <a name="t_primitive">Primitive Types</a>
1755</h3>
Chris Lattner8f8c7b72008-01-04 04:34:14 +0000[diff] [blame]1756
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1757<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1758
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1759<p>The primitive types are the fundamental building blocks of the LLVM
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1760 system.</p>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1761
1762<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1763<h4>
1764 <a name="t_integer">Integer Type</a>
1765</h4>
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]1766
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1767<div>
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]1768
1769<h5>Overview:</h5>
1770<p>The integer type is a very simple type that simply specifies an arbitrary
1771 bit width for the integer type desired. Any bit width from 1 bit to
1772 2<sup>23</sup>-1 (about 8 million) can be specified.</p>
1773
1774<h5>Syntax:</h5>
1775<pre>
1776 iN
1777</pre>
1778
1779<p>The number of bits the integer will occupy is specified by the <tt>N</tt>
1780 value.</p>
1781
1782<h5>Examples:</h5>
1783<table class="layout">
1784 <tr class="layout">
1785 <td class="left"><tt>i1</tt></td>
1786 <td class="left">a single-bit integer.</td>
1787 </tr>
1788 <tr class="layout">
1789 <td class="left"><tt>i32</tt></td>
1790 <td class="left">a 32-bit integer.</td>
1791 </tr>
1792 <tr class="layout">
1793 <td class="left"><tt>i1942652</tt></td>
1794 <td class="left">a really big integer of over 1 million bits.</td>
1795 </tr>
1796</table>
1797
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]1798</div>
1799
1800<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1801<h4>
1802 <a name="t_floating">Floating Point Types</a>
1803</h4>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1804
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1805<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1806
1807<table>
1808 <tbody>
1809 <tr><th>Type</th><th>Description</th></tr>
1810 <tr><td><tt>float</tt></td><td>32-bit floating point value</td></tr>
1811 <tr><td><tt>double</tt></td><td>64-bit floating point value</td></tr>
1812 <tr><td><tt>fp128</tt></td><td>128-bit floating point value (112-bit mantissa)</td></tr>
1813 <tr><td><tt>x86_fp80</tt></td><td>80-bit floating point value (X87)</td></tr>
1814 <tr><td><tt>ppc_fp128</tt></td><td>128-bit floating point value (two 64-bits)</td></tr>
1815 </tbody>
1816</table>
1817
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1818</div>
1819
1820<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1821<h4>
1822 <a name="t_x86mmx">X86mmx Type</a>
1823</h4>
Dale Johannesen21fe99b2010-10-01 00:48:59 +0000[diff] [blame]1824
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1825<div>
Dale Johannesen21fe99b2010-10-01 00:48:59 +0000[diff] [blame]1826
1827<h5>Overview:</h5>
1828<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>
1829
1830<h5>Syntax:</h5>
1831<pre>
Dale Johannesen473a8c82010-10-01 01:07:02 +0000[diff] [blame]1832 x86mmx
Dale Johannesen21fe99b2010-10-01 00:48:59 +0000[diff] [blame]1833</pre>
1834
1835</div>
1836
1837<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1838<h4>
1839 <a name="t_void">Void Type</a>
1840</h4>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1841
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1842<div>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1843
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1844<h5>Overview:</h5>
1845<p>The void type does not represent any value and has no size.</p>
1846
1847<h5>Syntax:</h5>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1848<pre>
1849 void
1850</pre>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1851
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1852</div>
1853
1854<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1855<h4>
1856 <a name="t_label">Label Type</a>
1857</h4>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1858
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1859<div>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1860
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1861<h5>Overview:</h5>
1862<p>The label type represents code labels.</p>
1863
1864<h5>Syntax:</h5>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1865<pre>
1866 label
1867</pre>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1868
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1869</div>
1870
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1871<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1872<h4>
1873 <a name="t_metadata">Metadata Type</a>
1874</h4>
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1875
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1876<div>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1877
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1878<h5>Overview:</h5>
Nick Lewyckyc261df92009-09-27 23:27:42 +0000[diff] [blame]1879<p>The metadata type represents embedded metadata. No derived types may be
1880 created from metadata except for <a href="#t_function">function</a>
1881 arguments.
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1882
1883<h5>Syntax:</h5>
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1884<pre>
1885 metadata
1886</pre>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1887
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1888</div>
1889
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1890</div>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1891
1892<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1893<h3>
1894 <a name="t_derived">Derived Types</a>
1895</h3>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1896
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1897<div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1898
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1899<p>The real power in LLVM comes from the derived types in the system. This is
1900 what allows a programmer to represent arrays, functions, pointers, and other
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]1901 useful types. Each of these types contain one or more element types which
1902 may be a primitive type, or another derived type. For example, it is
1903 possible to have a two dimensional array, using an array as the element type
1904 of another array.</p>
Dan Gohmand8791e52009-01-24 15:58:40 +0000[diff] [blame]1905
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]1906<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1907<h4>
1908 <a name="t_aggregate">Aggregate Types</a>
1909</h4>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]1910
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1911<div>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]1912
1913<p>Aggregate Types are a subset of derived types that can contain multiple
1914 member types. <a href="#t_array">Arrays</a>,
Chris Lattner61c70e92010-08-28 04:09:24 +0000[diff] [blame]1915 <a href="#t_struct">structs</a>, and <a href="#t_vector">vectors</a> are
1916 aggregate types.</p>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]1917
1918</div>
1919
Reid Spencer2b916312007-05-16 18:44:01 +0000[diff] [blame]1920<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1921<h4>
1922 <a name="t_array">Array Type</a>
1923</h4>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1924
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1925<div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1926
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1927<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1928<p>The array type is a very simple derived type that arranges elements
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1929 sequentially in memory. The array type requires a size (number of elements)
1930 and an underlying data type.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1931
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1932<h5>Syntax:</h5>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1933<pre>
1934 [&lt;# elements&gt; x &lt;elementtype&gt;]
1935</pre>
1936
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1937<p>The number of elements is a constant integer value; <tt>elementtype</tt> may
1938 be any type with a size.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1939
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1940<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1941<table class="layout">
1942 <tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1943 <td class="left"><tt>[40 x i32]</tt></td>
1944 <td class="left">Array of 40 32-bit integer values.</td>
1945 </tr>
1946 <tr class="layout">
1947 <td class="left"><tt>[41 x i32]</tt></td>
1948 <td class="left">Array of 41 32-bit integer values.</td>
1949 </tr>
1950 <tr class="layout">
1951 <td class="left"><tt>[4 x i8]</tt></td>
1952 <td class="left">Array of 4 8-bit integer values.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1953 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1954</table>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1955<p>Here are some examples of multidimensional arrays:</p>
1956<table class="layout">
1957 <tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1958 <td class="left"><tt>[3 x [4 x i32]]</tt></td>
1959 <td class="left">3x4 array of 32-bit integer values.</td>
1960 </tr>
1961 <tr class="layout">
1962 <td class="left"><tt>[12 x [10 x float]]</tt></td>
1963 <td class="left">12x10 array of single precision floating point values.</td>
1964 </tr>
1965 <tr class="layout">
1966 <td class="left"><tt>[2 x [3 x [4 x i16]]]</tt></td>
1967 <td class="left">2x3x4 array of 16-bit integer values.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1968 </tr>
1969</table>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]1970
Dan Gohman7657f6b2009-11-09 19:01:53 +0000[diff] [blame]1971<p>There is no restriction on indexing beyond the end of the array implied by
1972 a static type (though there are restrictions on indexing beyond the bounds
1973 of an allocated object in some cases). This means that single-dimension
1974 'variable sized array' addressing can be implemented in LLVM with a zero
1975 length array type. An implementation of 'pascal style arrays' in LLVM could
1976 use the type "<tt>{ i32, [0 x float]}</tt>", for example.</p>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]1977
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1978</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1979
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1980<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1981<h4>
1982 <a name="t_function">Function Type</a>
1983</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1984
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1985<div>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]1986
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1987<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1988<p>The function type can be thought of as a function signature. It consists of
1989 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]1990 function type is a first class type or a void type.</p>
Devang Patelc3fc6df2008-03-10 20:49:15 +0000[diff] [blame]1991
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1992<h5>Syntax:</h5>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]1993<pre>
Nick Lewycky51386942009-09-27 07:55:32 +0000[diff] [blame]1994 &lt;returntype&gt; (&lt;parameter list&gt;)
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]1995</pre>
1996
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]1997<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]1998 specifiers. Optionally, the parameter list may include a type <tt>...</tt>,
1999 which indicates that the function takes a variable number of arguments.
2000 Variable argument functions can access their arguments with
2001 the <a href="#int_varargs">variable argument handling intrinsic</a>
Chris Lattner0724fbd2010-03-02 06:36:51 +0000[diff] [blame]2002 functions. '<tt>&lt;returntype&gt;</tt>' is any type except
Nick Lewyckyc261df92009-09-27 23:27:42 +0000[diff] [blame]2003 <a href="#t_label">label</a>.</p>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]2004
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2005<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]2006<table class="layout">
2007 <tr class="layout">
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]2008 <td class="left"><tt>i32 (i32)</tt></td>
2009 <td class="left">function taking an <tt>i32</tt>, returning an <tt>i32</tt>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]2010 </td>
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]2011 </tr><tr class="layout">
Chris Lattner0724fbd2010-03-02 06:36:51 +0000[diff] [blame]2012 <td class="left"><tt>float&nbsp;(i16,&nbsp;i32&nbsp;*)&nbsp;*
Reid Spencerf17a0b72006-12-31 07:20:23 +0000[diff] [blame]2013 </tt></td>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]2014 <td class="left"><a href="#t_pointer">Pointer</a> to a function that takes
Chris Lattner0724fbd2010-03-02 06:36:51 +0000[diff] [blame]2015 an <tt>i16</tt> and a <a href="#t_pointer">pointer</a> to <tt>i32</tt>,
2016 returning <tt>float</tt>.
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]2017 </td>
2018 </tr><tr class="layout">
2019 <td class="left"><tt>i32 (i8*, ...)</tt></td>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]2020 <td class="left">A vararg function that takes at least one
2021 <a href="#t_pointer">pointer</a> to <tt>i8 </tt> (char in C),
2022 which returns an integer. This is the signature for <tt>printf</tt> in
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]2023 LLVM.
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]2024 </td>
Devang Patela582f402008-03-24 05:35:41 +0000[diff] [blame]2025 </tr><tr class="layout">
2026 <td class="left"><tt>{i32, i32} (i32)</tt></td>
Nick Lewycky51386942009-09-27 07:55:32 +0000[diff] [blame]2027 <td class="left">A function taking an <tt>i32</tt>, returning a
2028 <a href="#t_struct">structure</a> containing two <tt>i32</tt> values
Devang Patela582f402008-03-24 05:35:41 +0000[diff] [blame]2029 </td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]2030 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2031</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]2032
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2033</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2034
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2035<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2036<h4>
2037 <a name="t_struct">Structure Type</a>
2038</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2039
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2040<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2041
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2042<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2043<p>The structure type is used to represent a collection of data members together
Chris Lattner1afcace2011-07-09 17:41:24 +0000[diff] [blame]2044 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]2045
Jeffrey Yasskin7a088cf2010-01-11 19:19:26 +0000[diff] [blame]2046<p>Structures in memory are accessed using '<tt><a href="#i_load">load</a></tt>'
2047 and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a field
2048 with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.
2049 Structures in registers are accessed using the
2050 '<tt><a href="#i_extractvalue">extractvalue</a></tt>' and
2051 '<tt><a href="#i_insertvalue">insertvalue</a></tt>' instructions.</p>
Chris Lattner1afcace2011-07-09 17:41:24 +0000[diff] [blame]2052
2053<p>Structures may optionally be "packed" structures, which indicate that the
2054 alignment of the struct is one byte, and that there is no padding between
Chris Lattner2c38d652011-08-12 17:31:02 +0000[diff] [blame]2055 the elements. In non-packed structs, padding between field types is inserted
2056 as defined by the TargetData string in the module, which is required to match
Chris Lattnere4617b02011-10-11 23:02:17 +0000[diff] [blame]2057 what the underlying code generator expects.</p>
Chris Lattner1afcace2011-07-09 17:41:24 +0000[diff] [blame]2058
Chris Lattner2c38d652011-08-12 17:31:02 +0000[diff] [blame]2059<p>Structures can either be "literal" or "identified". A literal structure is
2060 defined inline with other types (e.g. <tt>{i32, i32}*</tt>) whereas identified
2061 types are always defined at the top level with a name. Literal types are
2062 uniqued by their contents and can never be recursive or opaque since there is
Chris Lattneraa175c32011-08-12 18:12:40 +0000[diff] [blame]2063 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]2064 never uniqued.
Chris Lattner1afcace2011-07-09 17:41:24 +0000[diff] [blame]2065</p>
2066
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2067<h5>Syntax:</h5>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]2068<pre>
Chris Lattner2c38d652011-08-12 17:31:02 +0000[diff] [blame]2069 %T1 = type { &lt;type list&gt; } <i>; Identified normal struct type</i>
2070 %T2 = type &lt;{ &lt;type list&gt; }&gt; <i>; Identified packed struct type</i>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]2071</pre>
Chris Lattner1afcace2011-07-09 17:41:24 +0000[diff] [blame]2072
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2073<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]2074<table class="layout">
2075 <tr class="layout">
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]2076 <td class="left"><tt>{ i32, i32, i32 }</tt></td>
2077 <td class="left">A triple of three <tt>i32</tt> values</td>
Chris Lattner1afcace2011-07-09 17:41:24 +0000[diff] [blame]2078 </tr>
2079 <tr class="layout">
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]2080 <td class="left"><tt>{&nbsp;float,&nbsp;i32&nbsp;(i32)&nbsp;*&nbsp;}</tt></td>
2081 <td class="left">A pair, where the first element is a <tt>float</tt> and the
2082 second element is a <a href="#t_pointer">pointer</a> to a
2083 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
2084 an <tt>i32</tt>.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]2085 </tr>
Chris Lattner1afcace2011-07-09 17:41:24 +0000[diff] [blame]2086 <tr class="layout">
2087 <td class="left"><tt>&lt;{ i8, i32 }&gt;</tt></td>
2088 <td class="left">A packed struct known to be 5 bytes in size.</td>
2089 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2090</table>
Dan Gohmand8791e52009-01-24 15:58:40 +0000[diff] [blame]2091
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2092</div>
Chris Lattner1afcace2011-07-09 17:41:24 +0000[diff] [blame]2093
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2094<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2095<h4>
Chris Lattner628ed392011-07-23 19:59:08 +0000[diff] [blame]2096 <a name="t_opaque">Opaque Structure Types</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2097</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2098
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2099<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2100
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]2101<h5>Overview:</h5>
Chris Lattner628ed392011-07-23 19:59:08 +0000[diff] [blame]2102<p>Opaque structure types are used to represent named structure types that do
2103 not have a body specified. This corresponds (for example) to the C notion of
2104 a forward declared structure.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2105
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]2106<h5>Syntax:</h5>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]2107<pre>
Chris Lattner1afcace2011-07-09 17:41:24 +0000[diff] [blame]2108 %X = type opaque
2109 %52 = type opaque
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]2110</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2111
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]2112<h5>Examples:</h5>
2113<table class="layout">
2114 <tr class="layout">
Chris Lattner1afcace2011-07-09 17:41:24 +0000[diff] [blame]2115 <td class="left"><tt>opaque</tt></td>
2116 <td class="left">An opaque type.</td>
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]2117 </tr>
2118</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2119
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]2120</div>
2121
Chris Lattner1afcace2011-07-09 17:41:24 +0000[diff] [blame]2122
2123
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]2124<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2125<h4>
2126 <a name="t_pointer">Pointer Type</a>
2127</h4>
Chris Lattner0fd4a272009-02-08 19:53:29 +0000[diff] [blame]2128
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2129<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2130
2131<h5>Overview:</h5>
Dan Gohmanff3ef322010-02-25 16:50:07 +0000[diff] [blame]2132<p>The pointer type is used to specify memory locations.
2133 Pointers are commonly used to reference objects in memory.</p>
2134
2135<p>Pointer types may have an optional address space attribute defining the
2136 numbered address space where the pointed-to object resides. The default
2137 address space is number zero. The semantics of non-zero address
2138 spaces are target-specific.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2139
2140<p>Note that LLVM does not permit pointers to void (<tt>void*</tt>) nor does it
2141 permit pointers to labels (<tt>label*</tt>). Use <tt>i8*</tt> instead.</p>
Chris Lattner0fd4a272009-02-08 19:53:29 +0000[diff] [blame]2142
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2143<h5>Syntax:</h5>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]2144<pre>
2145 &lt;type&gt; *
2146</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2147
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2148<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]2149<table class="layout">
2150 <tr class="layout">
Dan Gohman2a08c532009-01-04 23:44:43 +0000[diff] [blame]2151 <td class="left"><tt>[4 x i32]*</tt></td>
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]2152 <td class="left">A <a href="#t_pointer">pointer</a> to <a
2153 href="#t_array">array</a> of four <tt>i32</tt> values.</td>
2154 </tr>
2155 <tr class="layout">
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]2156 <td class="left"><tt>i32 (i32*) *</tt></td>
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]2157 <td class="left"> A <a href="#t_pointer">pointer</a> to a <a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2158 href="#t_function">function</a> that takes an <tt>i32*</tt>, returning an
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]2159 <tt>i32</tt>.</td>
2160 </tr>
2161 <tr class="layout">
2162 <td class="left"><tt>i32 addrspace(5)*</tt></td>
2163 <td class="left">A <a href="#t_pointer">pointer</a> to an <tt>i32</tt> value
2164 that resides in address space #5.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]2165 </tr>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2166</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2167
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2168</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]2169
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]2170<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2171<h4>
2172 <a name="t_vector">Vector Type</a>
2173</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2174
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2175<div>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]2176
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]2177<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2178<p>A vector type is a simple derived type that represents a vector of elements.
2179 Vector types are used when multiple primitive data are operated in parallel
2180 using a single instruction (SIMD). A vector type requires a size (number of
Duncan Sandsd40d14e2009-11-27 13:38:03 +0000[diff] [blame]2181 elements) and an underlying primitive data type. Vector types are considered
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2182 <a href="#t_firstclass">first class</a>.</p>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]2183
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]2184<h5>Syntax:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]2185<pre>
2186 &lt; &lt;# elements&gt; x &lt;elementtype&gt; &gt;
2187</pre>
2188
Chris Lattner7d2e7be2010-10-10 18:20:35 +0000[diff] [blame]2189<p>The number of elements is a constant integer value larger than 0; elementtype
2190 may be any integer or floating point type. Vectors of size zero are not
2191 allowed, and pointers are not allowed as the element type.</p>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]2192
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]2193<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]2194<table class="layout">
2195 <tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]2196 <td class="left"><tt>&lt;4 x i32&gt;</tt></td>
2197 <td class="left">Vector of 4 32-bit integer values.</td>
2198 </tr>
2199 <tr class="layout">
2200 <td class="left"><tt>&lt;8 x float&gt;</tt></td>
2201 <td class="left">Vector of 8 32-bit floating-point values.</td>
2202 </tr>
2203 <tr class="layout">
2204 <td class="left"><tt>&lt;2 x i64&gt;</tt></td>
2205 <td class="left">Vector of 2 64-bit integer values.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]2206 </tr>
2207</table>
Dan Gohmand8791e52009-01-24 15:58:40 +0000[diff] [blame]2208
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2209</div>
2210
Bill Wendlingaf75f0c2011-07-31 06:47:33 +0000[diff] [blame]2211</div>
2212
NAKAMURA Takumi4b2e07a2011-10-31 13:04:26 +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
Peter Collingbourne999f90b2011-10-27 19:19:14 +0000[diff] [blame]2969<h4>
2970 <a name="fpaccuracy">'<tt>fpaccuracy</tt>' Metadata</a>
2971</h4>
2972
2973<div>
2974
2975<p><tt>fpaccuracy</tt> metadata may be attached to any instruction of floating
2976 point type. It expresses the maximum relative error of the result of
2977 that instruction, in ULPs. ULP is defined as follows:</p>
2978
2979<blockquote><p>
2980If x is a real number that lies between two finite consecutive floating-point
2981numbers a and b, without being equal to one of them, then ulp(x) = |b - a|,
2982otherwise ulp(x) is the distance between the two non-equal finite
2983floating-point numbers nearest x. Moreover, ulp(NaN) is NaN.
2984</p></blockquote>
2985
2986<p>The maximum relative error may be any rational number. The metadata node
2987 shall consist of a pair of unsigned integers respectively representing
2988 the numerator and denominator. For example, 2.5 ULP:</p>
2989
2990<div class="doc_code">
2991<pre>
2992!0 = metadata !{ i32 5, i32 2 }
2993</pre>
2994</div>
2995
2996</div>
2997
Chris Lattnere6a5ddd2010-01-15 21:50:19 +0000[diff] [blame]2998</div>
2999
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3000</div>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3001
3002<!-- *********************************************************************** -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3003<h2>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3004 <a name="intrinsic_globals">Intrinsic Global Variables</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3005</h2>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3006<!-- *********************************************************************** -->
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3007<div>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3008<p>LLVM has a number of "magic" global variables that contain data that affect
3009code generation or other IR semantics. These are documented here. All globals
Chris Lattner401e10c2009-07-20 06:14:25 +0000[diff] [blame]3010of this sort should have a section specified as "<tt>llvm.metadata</tt>". This
3011section and all globals that start with "<tt>llvm.</tt>" are reserved for use
3012by LLVM.</p>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3013
3014<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3015<h3>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3016<a name="intg_used">The '<tt>llvm.used</tt>' Global Variable</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3017</h3>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3018
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3019<div>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3020
3021<p>The <tt>@llvm.used</tt> global is an array with i8* element type which has <a
3022href="#linkage_appending">appending linkage</a>. This array contains a list of
3023pointers to global variables and functions which may optionally have a pointer
3024cast formed of bitcast or getelementptr. For example, a legal use of it is:</p>
3025
3026<pre>
3027 @X = global i8 4
3028 @Y = global i32 123
3029
3030 @llvm.used = appending global [2 x i8*] [
3031 i8* @X,
3032 i8* bitcast (i32* @Y to i8*)
3033 ], section "llvm.metadata"
3034</pre>
3035
3036<p>If a global variable appears in the <tt>@llvm.used</tt> list, then the
3037compiler, assembler, and linker are required to treat the symbol as if there is
3038a reference to the global that it cannot see. For example, if a variable has
3039internal linkage and no references other than that from the <tt>@llvm.used</tt>
3040list, it cannot be deleted. This is commonly used to represent references from
3041inline asms and other things the compiler cannot "see", and corresponds to
3042"attribute((used))" in GNU C.</p>
3043
3044<p>On some targets, the code generator must emit a directive to the assembler or
3045object file to prevent the assembler and linker from molesting the symbol.</p>
3046
3047</div>
3048
3049<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3050<h3>
3051 <a name="intg_compiler_used">
3052 The '<tt>llvm.compiler.used</tt>' Global Variable
3053 </a>
3054</h3>
Chris Lattner401e10c2009-07-20 06:14:25 +0000[diff] [blame]3055
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3056<div>
Chris Lattner401e10c2009-07-20 06:14:25 +0000[diff] [blame]3057
3058<p>The <tt>@llvm.compiler.used</tt> directive is the same as the
3059<tt>@llvm.used</tt> directive, except that it only prevents the compiler from
3060touching the symbol. On targets that support it, this allows an intelligent
3061linker to optimize references to the symbol without being impeded as it would be
3062by <tt>@llvm.used</tt>.</p>
3063
3064<p>This is a rare construct that should only be used in rare circumstances, and
3065should not be exposed to source languages.</p>
3066
3067</div>
3068
3069<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3070<h3>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3071<a name="intg_global_ctors">The '<tt>llvm.global_ctors</tt>' Global Variable</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3072</h3>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3073
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3074<div>
David Chisnalle31e9962010-04-30 19:23:49 +0000[diff] [blame]3075<pre>
3076%0 = type { i32, void ()* }
David Chisnall27195a52010-04-30 19:27:35 +0000[diff] [blame]3077@llvm.global_ctors = appending global [1 x %0] [%0 { i32 65535, void ()* @ctor }]
David Chisnalle31e9962010-04-30 19:23:49 +0000[diff] [blame]3078</pre>
3079<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.
3080</p>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3081
3082</div>
3083
3084<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3085<h3>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3086<a name="intg_global_dtors">The '<tt>llvm.global_dtors</tt>' Global Variable</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3087</h3>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3088
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3089<div>
David Chisnalle31e9962010-04-30 19:23:49 +0000[diff] [blame]3090<pre>
3091%0 = type { i32, void ()* }
David Chisnall27195a52010-04-30 19:27:35 +0000[diff] [blame]3092@llvm.global_dtors = appending global [1 x %0] [%0 { i32 65535, void ()* @dtor }]
David Chisnalle31e9962010-04-30 19:23:49 +0000[diff] [blame]3093</pre>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3094
David Chisnalle31e9962010-04-30 19:23:49 +0000[diff] [blame]3095<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.
3096</p>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3097
3098</div>
3099
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3100</div>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3101
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]3102<!-- *********************************************************************** -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3103<h2><a name="instref">Instruction Reference</a></h2>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3104<!-- *********************************************************************** -->
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]3105
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3106<div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]3107
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3108<p>The LLVM instruction set consists of several different classifications of
3109 instructions: <a href="#terminators">terminator
3110 instructions</a>, <a href="#binaryops">binary instructions</a>,
3111 <a href="#bitwiseops">bitwise binary instructions</a>,
3112 <a href="#memoryops">memory instructions</a>, and
3113 <a href="#otherops">other instructions</a>.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]3114
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3115<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3116<h3>
3117 <a name="terminators">Terminator Instructions</a>
3118</h3>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]3119
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3120<div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]3121
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3122<p>As mentioned <a href="#functionstructure">previously</a>, every basic block
3123 in a program ends with a "Terminator" instruction, which indicates which
3124 block should be executed after the current block is finished. These
3125 terminator instructions typically yield a '<tt>void</tt>' value: they produce
3126 control flow, not values (the one exception being the
3127 '<a href="#i_invoke"><tt>invoke</tt></a>' instruction).</p>
3128
Chris Lattner6445ecb2011-08-02 20:29:13 +0000[diff] [blame]3129<p>The terminator instructions are:
3130 '<a href="#i_ret"><tt>ret</tt></a>',
3131 '<a href="#i_br"><tt>br</tt></a>',
3132 '<a href="#i_switch"><tt>switch</tt></a>',
3133 '<a href="#i_indirectbr"><tt>indirectbr</tt></a>',
3134 '<a href="#i_invoke"><tt>invoke</tt></a>',
3135 '<a href="#i_unwind"><tt>unwind</tt></a>',
3136 '<a href="#i_resume"><tt>resume</tt></a>', and
3137 '<a href="#i_unreachable"><tt>unreachable</tt></a>'.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]3138
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3139<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3140<h4>
3141 <a name="i_ret">'<tt>ret</tt>' Instruction</a>
3142</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3143
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3144<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3145
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3146<h5>Syntax:</h5>
Dan Gohmanb1e6b962008-10-04 19:00:07 +0000[diff] [blame]3147<pre>
3148 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]3149 ret void <i>; Return from void function</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3150</pre>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]3151
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3152<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3153<p>The '<tt>ret</tt>' instruction is used to return control flow (and optionally
3154 a value) from a function back to the caller.</p>
3155
3156<p>There are two forms of the '<tt>ret</tt>' instruction: one that returns a
3157 value and then causes control flow, and one that just causes control flow to
3158 occur.</p>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]3159
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3160<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3161<p>The '<tt>ret</tt>' instruction optionally accepts a single argument, the
3162 return value. The type of the return value must be a
3163 '<a href="#t_firstclass">first class</a>' type.</p>
Dan Gohmanb1e6b962008-10-04 19:00:07 +0000[diff] [blame]3164
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3165<p>A function is not <a href="#wellformed">well formed</a> if it it has a
3166 non-void return type and contains a '<tt>ret</tt>' instruction with no return
3167 value or a return value with a type that does not match its type, or if it
3168 has a void return type and contains a '<tt>ret</tt>' instruction with a
3169 return value.</p>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]3170
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3171<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3172<p>When the '<tt>ret</tt>' instruction is executed, control flow returns back to
3173 the calling function's context. If the caller is a
3174 "<a href="#i_call"><tt>call</tt></a>" instruction, execution continues at the
3175 instruction after the call. If the caller was an
3176 "<a href="#i_invoke"><tt>invoke</tt></a>" instruction, execution continues at
3177 the beginning of the "normal" destination block. If the instruction returns
3178 a value, that value shall set the call or invoke instruction's return
3179 value.</p>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]3180
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3181<h5>Example:</h5>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]3182<pre>
3183 ret i32 5 <i>; Return an integer value of 5</i>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]3184 ret void <i>; Return from a void function</i>
Bill Wendling0a4bbbf2009-02-28 22:12:54 +0000[diff] [blame]3185 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]3186</pre>
Dan Gohmanf3e60bd2009-01-12 23:12:39 +0000[diff] [blame]3187
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3188</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3189<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3190<h4>
3191 <a name="i_br">'<tt>br</tt>' Instruction</a>
3192</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3193
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3194<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3195
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3196<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3197<pre>
Bill Wendlingb3aa4712011-07-26 10:41:15 +0000[diff] [blame]3198 br i1 &lt;cond&gt;, label &lt;iftrue&gt;, label &lt;iffalse&gt;
3199 br label &lt;dest&gt; <i>; Unconditional branch</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3200</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3201
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3202<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3203<p>The '<tt>br</tt>' instruction is used to cause control flow to transfer to a
3204 different basic block in the current function. There are two forms of this
3205 instruction, corresponding to a conditional branch and an unconditional
3206 branch.</p>
3207
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3208<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3209<p>The conditional branch form of the '<tt>br</tt>' instruction takes a single
3210 '<tt>i1</tt>' value and two '<tt>label</tt>' values. The unconditional form
3211 of the '<tt>br</tt>' instruction takes a single '<tt>label</tt>' value as a
3212 target.</p>
3213
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3214<h5>Semantics:</h5>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3215<p>Upon execution of a conditional '<tt>br</tt>' instruction, the '<tt>i1</tt>'
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3216 argument is evaluated. If the value is <tt>true</tt>, control flows to the
3217 '<tt>iftrue</tt>' <tt>label</tt> argument. If "cond" is <tt>false</tt>,
3218 control flows to the '<tt>iffalse</tt>' <tt>label</tt> argument.</p>
3219
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3220<h5>Example:</h5>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]3221<pre>
3222Test:
3223 %cond = <a href="#i_icmp">icmp</a> eq i32 %a, %b
3224 br i1 %cond, label %IfEqual, label %IfUnequal
3225IfEqual:
3226 <a href="#i_ret">ret</a> i32 1
3227IfUnequal:
3228 <a href="#i_ret">ret</a> i32 0
3229</pre>
3230
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3231</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3232
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3233<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3234<h4>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3235 <a name="i_switch">'<tt>switch</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3236</h4>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3237
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3238<div>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3239
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3240<h5>Syntax:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3241<pre>
3242 switch &lt;intty&gt; &lt;value&gt;, label &lt;defaultdest&gt; [ &lt;intty&gt; &lt;val&gt;, label &lt;dest&gt; ... ]
3243</pre>
3244
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3245<h5>Overview:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3246<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]3247 several different places. It is a generalization of the '<tt>br</tt>'
3248 instruction, allowing a branch to occur to one of many possible
3249 destinations.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3250
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3251<h5>Arguments:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3252<p>The '<tt>switch</tt>' instruction uses three parameters: an integer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3253 comparison value '<tt>value</tt>', a default '<tt>label</tt>' destination,
3254 and an array of pairs of comparison value constants and '<tt>label</tt>'s.
3255 The table is not allowed to contain duplicate constant entries.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3256
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3257<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3258<p>The <tt>switch</tt> instruction specifies a table of values and
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3259 destinations. When the '<tt>switch</tt>' instruction is executed, this table
3260 is searched for the given value. If the value is found, control flow is
Benjamin Kramer8040cd32009-10-12 14:46:08 +0000[diff] [blame]3261 transferred to the corresponding destination; otherwise, control flow is
3262 transferred to the default destination.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3263
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3264<h5>Implementation:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3265<p>Depending on properties of the target machine and the particular
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3266 <tt>switch</tt> instruction, this instruction may be code generated in
3267 different ways. For example, it could be generated as a series of chained
3268 conditional branches or with a lookup table.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3269
3270<h5>Example:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3271<pre>
3272 <i>; Emulate a conditional br instruction</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3273 %Val = <a href="#i_zext">zext</a> i1 %value to i32
Dan Gohman2a08c532009-01-04 23:44:43 +0000[diff] [blame]3274 switch i32 %Val, label %truedest [ i32 0, label %falsedest ]
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3275
3276 <i>; Emulate an unconditional br instruction</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3277 switch i32 0, label %dest [ ]
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3278
3279 <i>; Implement a jump table:</i>
Dan Gohman2a08c532009-01-04 23:44:43 +0000[diff] [blame]3280 switch i32 %val, label %otherwise [ i32 0, label %onzero
3281 i32 1, label %onone
3282 i32 2, label %ontwo ]
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3283</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3284
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3285</div>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3286
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]3287
3288<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3289<h4>
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]3290 <a name="i_indirectbr">'<tt>indirectbr</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3291</h4>
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]3292
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3293<div>
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]3294
3295<h5>Syntax:</h5>
3296<pre>
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]3297 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]3298</pre>
3299
3300<h5>Overview:</h5>
3301
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]3302<p>The '<tt>indirectbr</tt>' instruction implements an indirect branch to a label
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]3303 within the current function, whose address is specified by
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]3304 "<tt>address</tt>". Address must be derived from a <a
3305 href="#blockaddress">blockaddress</a> constant.</p>
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]3306
3307<h5>Arguments:</h5>
3308
3309<p>The '<tt>address</tt>' argument is the address of the label to jump to. The
3310 rest of the arguments indicate the full set of possible destinations that the
3311 address may point to. Blocks are allowed to occur multiple times in the
3312 destination list, though this isn't particularly useful.</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3313
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]3314<p>This destination list is required so that dataflow analysis has an accurate
3315 understanding of the CFG.</p>
3316
3317<h5>Semantics:</h5>
3318
3319<p>Control transfers to the block specified in the address argument. All
3320 possible destination blocks must be listed in the label list, otherwise this
3321 instruction has undefined behavior. This implies that jumps to labels
3322 defined in other functions have undefined behavior as well.</p>
3323
3324<h5>Implementation:</h5>
3325
3326<p>This is typically implemented with a jump through a register.</p>
3327
3328<h5>Example:</h5>
3329<pre>
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]3330 indirectbr i8* %Addr, [ label %bb1, label %bb2, label %bb3 ]
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]3331</pre>
3332
3333</div>
3334
3335
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3336<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3337<h4>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3338 <a name="i_invoke">'<tt>invoke</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3339</h4>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3340
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3341<div>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3342
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3343<h5>Syntax:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3344<pre>
Devang Patel307e8ab2008-10-07 17:48:33 +0000[diff] [blame]3345 &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]3346 to label &lt;normal label&gt; unwind label &lt;exception label&gt;
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3347</pre>
3348
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]3349<h5>Overview:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3350<p>The '<tt>invoke</tt>' instruction causes control to transfer to a specified
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3351 function, with the possibility of control flow transfer to either the
3352 '<tt>normal</tt>' label or the '<tt>exception</tt>' label. If the callee
3353 function returns with the "<tt><a href="#i_ret">ret</a></tt>" instruction,
3354 control flow will return to the "normal" label. If the callee (or any
3355 indirect callees) returns with the "<a href="#i_unwind"><tt>unwind</tt></a>"
3356 instruction, control is interrupted and continued at the dynamically nearest
3357 "exception" label.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3358
Bill Wendlingf78faf82011-08-02 21:52:38 +0000[diff] [blame]3359<p>The '<tt>exception</tt>' label is a
3360 <i><a href="ExceptionHandling.html#overview">landing pad</a></i> for the
3361 exception. As such, '<tt>exception</tt>' label is required to have the
3362 "<a href="#i_landingpad"><tt>landingpad</tt></a>" instruction, which contains
3363 the information about about the behavior of the program after unwinding
3364 happens, as its first non-PHI instruction. The restrictions on the
3365 "<tt>landingpad</tt>" instruction's tightly couples it to the
3366 "<tt>invoke</tt>" instruction, so that the important information contained
3367 within the "<tt>landingpad</tt>" instruction can't be lost through normal
3368 code motion.</p>
3369
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3370<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3371<p>This instruction requires several arguments:</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3372
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3373<ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3374 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
3375 convention</a> the call should use. If none is specified, the call
3376 defaults to using C calling conventions.</li>
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]3377
3378 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3379 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
3380 '<tt>inreg</tt>' attributes are valid here.</li>
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]3381
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3382 <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]3383 function value being invoked. In most cases, this is a direct function
3384 invocation, but indirect <tt>invoke</tt>s are just as possible, branching
3385 off an arbitrary pointer to function value.</li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3386
3387 <li>'<tt>function ptr val</tt>': An LLVM value containing a pointer to a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3388 function to be invoked. </li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3389
3390 <li>'<tt>function args</tt>': argument list whose types match the function
Chris Lattner0724fbd2010-03-02 06:36:51 +0000[diff] [blame]3391 signature argument types and parameter attributes. All arguments must be
3392 of <a href="#t_firstclass">first class</a> type. If the function
3393 signature indicates the function accepts a variable number of arguments,
3394 the extra arguments can be specified.</li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3395
3396 <li>'<tt>normal label</tt>': the label reached when the called function
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3397 executes a '<tt><a href="#i_ret">ret</a></tt>' instruction. </li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3398
3399 <li>'<tt>exception label</tt>': the label reached when a callee returns with
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3400 the <a href="#i_unwind"><tt>unwind</tt></a> instruction. </li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3401
Devang Patel307e8ab2008-10-07 17:48:33 +0000[diff] [blame]3402 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3403 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
3404 '<tt>readnone</tt>' attributes are valid here.</li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3405</ol>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3406
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3407<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3408<p>This instruction is designed to operate as a standard
3409 '<tt><a href="#i_call">call</a></tt>' instruction in most regards. The
3410 primary difference is that it establishes an association with a label, which
3411 is used by the runtime library to unwind the stack.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3412
3413<p>This instruction is used in languages with destructors to ensure that proper
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3414 cleanup is performed in the case of either a <tt>longjmp</tt> or a thrown
3415 exception. Additionally, this is important for implementation of
3416 '<tt>catch</tt>' clauses in high-level languages that support them.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3417
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3418<p>For the purposes of the SSA form, the definition of the value returned by the
3419 '<tt>invoke</tt>' instruction is deemed to occur on the edge from the current
3420 block to the "normal" label. If the callee unwinds then no return value is
3421 available.</p>
Dan Gohmanf96a4992009-05-22 21:47:08 +0000[diff] [blame]3422
Chris Lattnerdf7a6802010-01-15 18:08:37 +0000[diff] [blame]3423<p>Note that the code generator does not yet completely support unwind, and
3424that the invoke/unwind semantics are likely to change in future versions.</p>
3425
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3426<h5>Example:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3427<pre>
Nick Lewyckyd703f652008-03-16 07:18:12 +0000[diff] [blame]3428 %retval = invoke i32 @Test(i32 15) to label %Continue
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]3429 unwind label %TestCleanup <i>; {i32}:retval set</i>
Nick Lewyckyd703f652008-03-16 07:18:12 +0000[diff] [blame]3430 %retval = invoke <a href="#callingconv">coldcc</a> i32 %Testfnptr(i32 15) to label %Continue
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]3431 unwind label %TestCleanup <i>; {i32}:retval set</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3432</pre>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3433
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3434</div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3435
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]3436<!-- _______________________________________________________________________ -->
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3437
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3438<h4>
3439 <a name="i_unwind">'<tt>unwind</tt>' Instruction</a>
3440</h4>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3441
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3442<div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3443
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]3444<h5>Syntax:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3445<pre>
3446 unwind
3447</pre>
3448
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]3449<h5>Overview:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3450<p>The '<tt>unwind</tt>' instruction unwinds the stack, continuing control flow
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3451 at the first callee in the dynamic call stack which used
3452 an <a href="#i_invoke"><tt>invoke</tt></a> instruction to perform the call.
3453 This is primarily used to implement exception handling.</p>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3454
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]3455<h5>Semantics:</h5>
Chris Lattner72ed2002008-04-19 21:01:16 +0000[diff] [blame]3456<p>The '<tt>unwind</tt>' instruction causes execution of the current function to
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3457 immediately halt. The dynamic call stack is then searched for the
3458 first <a href="#i_invoke"><tt>invoke</tt></a> instruction on the call stack.
3459 Once found, execution continues at the "exceptional" destination block
3460 specified by the <tt>invoke</tt> instruction. If there is no <tt>invoke</tt>
3461 instruction in the dynamic call chain, undefined behavior results.</p>
3462
Chris Lattnerdf7a6802010-01-15 18:08:37 +0000[diff] [blame]3463<p>Note that the code generator does not yet completely support unwind, and
3464that the invoke/unwind semantics are likely to change in future versions.</p>
3465
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3466</div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3467
Bill Wendlingdccc03b2011-07-31 06:30:59 +0000[diff] [blame]3468 <!-- _______________________________________________________________________ -->
3469
3470<h4>
3471 <a name="i_resume">'<tt>resume</tt>' Instruction</a>
3472</h4>
3473
3474<div>
3475
3476<h5>Syntax:</h5>
3477<pre>
3478 resume &lt;type&gt; &lt;value&gt;
3479</pre>
3480
3481<h5>Overview:</h5>
3482<p>The '<tt>resume</tt>' instruction is a terminator instruction that has no
3483 successors.</p>
3484
3485<h5>Arguments:</h5>
Bill Wendlingf78faf82011-08-02 21:52:38 +0000[diff] [blame]3486<p>The '<tt>resume</tt>' instruction requires one argument, which must have the
Bill Wendlinge4ad50b2011-08-03 18:37:32 +0000[diff] [blame]3487 same type as the result of any '<tt>landingpad</tt>' instruction in the same
3488 function.</p>
Bill Wendlingdccc03b2011-07-31 06:30:59 +0000[diff] [blame]3489
3490<h5>Semantics:</h5>
3491<p>The '<tt>resume</tt>' instruction resumes propagation of an existing
3492 (in-flight) exception whose unwinding was interrupted with
Bill Wendlingf78faf82011-08-02 21:52:38 +0000[diff] [blame]3493 a <a href="#i_landingpad"><tt>landingpad</tt></a> instruction.</p>
Bill Wendlingdccc03b2011-07-31 06:30:59 +0000[diff] [blame]3494
3495<h5>Example:</h5>
3496<pre>
Bill Wendlingf78faf82011-08-02 21:52:38 +0000[diff] [blame]3497 resume { i8*, i32 } %exn
Bill Wendlingdccc03b2011-07-31 06:30:59 +0000[diff] [blame]3498</pre>
3499
3500</div>
3501
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3502<!-- _______________________________________________________________________ -->
3503
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3504<h4>
3505 <a name="i_unreachable">'<tt>unreachable</tt>' Instruction</a>
3506</h4>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3507
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3508<div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3509
3510<h5>Syntax:</h5>
3511<pre>
3512 unreachable
3513</pre>
3514
3515<h5>Overview:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3516<p>The '<tt>unreachable</tt>' instruction has no defined semantics. This
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3517 instruction is used to inform the optimizer that a particular portion of the
3518 code is not reachable. This can be used to indicate that the code after a
3519 no-return function cannot be reached, and other facts.</p>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3520
3521<h5>Semantics:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3522<p>The '<tt>unreachable</tt>' instruction has no defined semantics.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3523
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3524</div>
3525
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3526</div>
3527
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3528<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3529<h3>
3530 <a name="binaryops">Binary Operations</a>
3531</h3>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3532
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3533<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3534
3535<p>Binary operators are used to do most of the computation in a program. They
3536 require two operands of the same type, execute an operation on them, and
3537 produce a single value. The operands might represent multiple data, as is
3538 the case with the <a href="#t_vector">vector</a> data type. The result value
3539 has the same type as its operands.</p>
3540
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3541<p>There are several different binary operators:</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3542
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3543<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3544<h4>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3545 <a name="i_add">'<tt>add</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3546</h4>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3547
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3548<div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3549
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3550<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3551<pre>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3552 &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]3553 &lt;result&gt; = add nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3554 &lt;result&gt; = add nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3555 &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]3556</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3557
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3558<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3559<p>The '<tt>add</tt>' instruction returns the sum of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3560
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3561<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3562<p>The two arguments to the '<tt>add</tt>' instruction must
3563 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3564 integer values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3565
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3566<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3567<p>The value produced is the integer sum of the two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3568
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3569<p>If the sum has unsigned overflow, the result returned is the mathematical
3570 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]3571
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3572<p>Because LLVM integers use a two's complement representation, this instruction
3573 is appropriate for both signed and unsigned integers.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3574
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]3575<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3576 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3577 <tt>nsw</tt> keywords are present, the result value of the <tt>add</tt>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]3578 is a <a href="#trapvalues">trap value</a> if unsigned and/or signed overflow,
3579 respectively, occurs.</p>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3580
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3581<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3582<pre>
3583 &lt;result&gt; = add i32 4, %var <i>; yields {i32}:result = 4 + %var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3584</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3585
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3586</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3587
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3588<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3589<h4>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3590 <a name="i_fadd">'<tt>fadd</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3591</h4>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3592
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3593<div>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3594
3595<h5>Syntax:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3596<pre>
3597 &lt;result&gt; = fadd &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3598</pre>
3599
3600<h5>Overview:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3601<p>The '<tt>fadd</tt>' instruction returns the sum of its two operands.</p>
3602
3603<h5>Arguments:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3604<p>The two arguments to the '<tt>fadd</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3605 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3606 floating point values. Both arguments must have identical types.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3607
3608<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3609<p>The value produced is the floating point sum of the two operands.</p>
3610
3611<h5>Example:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3612<pre>
3613 &lt;result&gt; = fadd float 4.0, %var <i>; yields {float}:result = 4.0 + %var</i>
3614</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3615
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3616</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3617
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3618<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3619<h4>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3620 <a name="i_sub">'<tt>sub</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3621</h4>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3622
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3623<div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3624
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3625<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3626<pre>
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]3627 &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]3628 &lt;result&gt; = sub nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3629 &lt;result&gt; = sub nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3630 &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]3631</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3632
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3633<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3634<p>The '<tt>sub</tt>' instruction returns the difference of its two
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3635 operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3636
3637<p>Note that the '<tt>sub</tt>' instruction is used to represent the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3638 '<tt>neg</tt>' instruction present in most other intermediate
3639 representations.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3640
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3641<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3642<p>The two arguments to the '<tt>sub</tt>' instruction must
3643 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3644 integer values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3645
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3646<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3647<p>The value produced is the integer difference of the two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3648
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3649<p>If the difference has unsigned overflow, the result returned is the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3650 mathematical result modulo 2<sup>n</sup>, where n is the bit width of the
3651 result.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3652
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3653<p>Because LLVM integers use a two's complement representation, this instruction
3654 is appropriate for both signed and unsigned integers.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3655
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]3656<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3657 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3658 <tt>nsw</tt> keywords are present, the result value of the <tt>sub</tt>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]3659 is a <a href="#trapvalues">trap value</a> if unsigned and/or signed overflow,
3660 respectively, occurs.</p>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3661
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3662<h5>Example:</h5>
Bill Wendlingaac388b2007-05-29 09:42:13 +0000[diff] [blame]3663<pre>
3664 &lt;result&gt; = sub i32 4, %var <i>; yields {i32}:result = 4 - %var</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3665 &lt;result&gt; = sub i32 0, %val <i>; yields {i32}:result = -%var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3666</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3667
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3668</div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3669
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3670<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3671<h4>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3672 <a name="i_fsub">'<tt>fsub</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3673</h4>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3674
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3675<div>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3676
3677<h5>Syntax:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3678<pre>
3679 &lt;result&gt; = fsub &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3680</pre>
3681
3682<h5>Overview:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3683<p>The '<tt>fsub</tt>' instruction returns the difference of its two
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3684 operands.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3685
3686<p>Note that the '<tt>fsub</tt>' instruction is used to represent the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3687 '<tt>fneg</tt>' instruction present in most other intermediate
3688 representations.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3689
3690<h5>Arguments:</h5>
Bill Wendlingd9fe2982009-07-20 02:32:41 +0000[diff] [blame]3691<p>The two arguments to the '<tt>fsub</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3692 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3693 floating point values. Both arguments must have identical types.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3694
3695<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3696<p>The value produced is the floating point difference of the two operands.</p>
3697
3698<h5>Example:</h5>
3699<pre>
3700 &lt;result&gt; = fsub float 4.0, %var <i>; yields {float}:result = 4.0 - %var</i>
3701 &lt;result&gt; = fsub float -0.0, %val <i>; yields {float}:result = -%var</i>
3702</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3703
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3704</div>
3705
3706<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3707<h4>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3708 <a name="i_mul">'<tt>mul</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3709</h4>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3710
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3711<div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3712
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3713<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3714<pre>
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]3715 &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]3716 &lt;result&gt; = mul nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3717 &lt;result&gt; = mul nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3718 &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]3719</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3720
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3721<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3722<p>The '<tt>mul</tt>' instruction returns the product of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3723
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3724<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3725<p>The two arguments to the '<tt>mul</tt>' instruction must
3726 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3727 integer values. Both arguments must have identical types.</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3728
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3729<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3730<p>The value produced is the integer product of the two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3731
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3732<p>If the result of the multiplication has unsigned overflow, the result
3733 returned is the mathematical result modulo 2<sup>n</sup>, where n is the bit
3734 width of the result.</p>
3735
3736<p>Because LLVM integers use a two's complement representation, and the result
3737 is the same width as the operands, this instruction returns the correct
3738 result for both signed and unsigned integers. If a full product
3739 (e.g. <tt>i32</tt>x<tt>i32</tt>-><tt>i64</tt>) is needed, the operands should
3740 be sign-extended or zero-extended as appropriate to the width of the full
3741 product.</p>
3742
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]3743<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3744 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3745 <tt>nsw</tt> keywords are present, the result value of the <tt>mul</tt>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]3746 is a <a href="#trapvalues">trap value</a> if unsigned and/or signed overflow,
3747 respectively, occurs.</p>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3748
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3749<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3750<pre>
3751 &lt;result&gt; = mul i32 4, %var <i>; yields {i32}:result = 4 * %var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3752</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3753
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3754</div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3755
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3756<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3757<h4>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3758 <a name="i_fmul">'<tt>fmul</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3759</h4>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3760
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3761<div>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3762
3763<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3764<pre>
3765 &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]3766</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3767
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3768<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3769<p>The '<tt>fmul</tt>' instruction returns the product of its two operands.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3770
3771<h5>Arguments:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3772<p>The two arguments to the '<tt>fmul</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3773 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3774 floating point values. Both arguments must have identical types.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3775
3776<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3777<p>The value produced is the floating point product of the two operands.</p>
3778
3779<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3780<pre>
3781 &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]3782</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3783
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3784</div>
3785
3786<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3787<h4>
3788 <a name="i_udiv">'<tt>udiv</tt>' Instruction</a>
3789</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3790
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3791<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3792
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3793<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3794<pre>
Chris Lattner35bda892011-02-06 21:44:57 +0000[diff] [blame]3795 &lt;result&gt; = udiv &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3796 &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]3797</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3798
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3799<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3800<p>The '<tt>udiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3801
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3802<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3803<p>The two arguments to the '<tt>udiv</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3804 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3805 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3806
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3807<h5>Semantics:</h5>
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3808<p>The value produced is the unsigned integer quotient of the two operands.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3809
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3810<p>Note that unsigned integer division and signed integer division are distinct
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3811 operations; for signed integer division, use '<tt>sdiv</tt>'.</p>
3812
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3813<p>Division by zero leads to undefined behavior.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3814
Chris Lattner35bda892011-02-06 21:44:57 +0000[diff] [blame]3815<p>If the <tt>exact</tt> keyword is present, the result value of the
3816 <tt>udiv</tt> is a <a href="#trapvalues">trap value</a> if %op1 is not a
3817 multiple of %op2 (as such, "((a udiv exact b) mul b) == a").</p>
3818
3819
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3820<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3821<pre>
3822 &lt;result&gt; = udiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3823</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3824
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3825</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3826
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3827<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3828<h4>
3829 <a name="i_sdiv">'<tt>sdiv</tt>' Instruction</a>
3830</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3831
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3832<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3833
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3834<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3835<pre>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3836 &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]3837 &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]3838</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3839
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3840<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3841<p>The '<tt>sdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3842
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3843<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3844<p>The two arguments to the '<tt>sdiv</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3845 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3846 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3847
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3848<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3849<p>The value produced is the signed integer quotient of the two operands rounded
3850 towards zero.</p>
3851
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3852<p>Note that signed integer division and unsigned integer division are distinct
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3853 operations; for unsigned integer division, use '<tt>udiv</tt>'.</p>
3854
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3855<p>Division by zero leads to undefined behavior. Overflow also leads to
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3856 undefined behavior; this is a rare case, but can occur, for example, by doing
3857 a 32-bit division of -2147483648 by -1.</p>
3858
Dan Gohman9c5beed2009-07-22 00:04:19 +0000[diff] [blame]3859<p>If the <tt>exact</tt> keyword is present, the result value of the
Dan Gohman27ef9972010-04-23 15:23:32 +0000[diff] [blame]3860 <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]3861 be rounded.</p>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3862
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3863<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3864<pre>
3865 &lt;result&gt; = sdiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3866</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3867
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3868</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3869
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3870<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3871<h4>
3872 <a name="i_fdiv">'<tt>fdiv</tt>' Instruction</a>
3873</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3874
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3875<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3876
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3877<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3878<pre>
Gabor Greiffb224a22008-08-07 21:46:00 +0000[diff] [blame]3879 &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]3880</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3881
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3882<h5>Overview:</h5>
3883<p>The '<tt>fdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3884
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3885<h5>Arguments:</h5>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]3886<p>The two arguments to the '<tt>fdiv</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3887 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3888 floating point values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3889
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3890<h5>Semantics:</h5>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3891<p>The value produced is the floating point quotient of the two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3892
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3893<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3894<pre>
3895 &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]3896</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3897
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3898</div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3899
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3900<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3901<h4>
3902 <a name="i_urem">'<tt>urem</tt>' Instruction</a>
3903</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3904
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3905<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3906
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3907<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3908<pre>
3909 &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]3910</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3911
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3912<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3913<p>The '<tt>urem</tt>' instruction returns the remainder from the unsigned
3914 division of its two arguments.</p>
3915
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3916<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3917<p>The two arguments to the '<tt>urem</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3918 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3919 values. Both arguments must have identical types.</p>
3920
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3921<h5>Semantics:</h5>
3922<p>This instruction returns the unsigned integer <i>remainder</i> of a division.
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3923 This instruction always performs an unsigned division to get the
3924 remainder.</p>
3925
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3926<p>Note that unsigned integer remainder and signed integer remainder are
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3927 distinct operations; for signed integer remainder, use '<tt>srem</tt>'.</p>
3928
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3929<p>Taking the remainder of a division by zero leads to undefined behavior.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3930
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3931<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3932<pre>
3933 &lt;result&gt; = urem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3934</pre>
3935
3936</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3937
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3938<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3939<h4>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3940 <a name="i_srem">'<tt>srem</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3941</h4>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3942
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3943<div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3944
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3945<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3946<pre>
Gabor Greiffb224a22008-08-07 21:46:00 +0000[diff] [blame]3947 &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]3948</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3949
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3950<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3951<p>The '<tt>srem</tt>' instruction returns the remainder from the signed
3952 division of its two operands. This instruction can also take
3953 <a href="#t_vector">vector</a> versions of the values in which case the
3954 elements must be integers.</p>
Chris Lattnerc7d3ab32008-01-04 04:33:49 +0000[diff] [blame]3955
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3956<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3957<p>The two arguments to the '<tt>srem</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3958 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3959 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3960
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3961<h5>Semantics:</h5>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3962<p>This instruction returns the <i>remainder</i> of a division (where the result
Duncan Sandsdea3a5e2011-03-07 09:12:24 +0000[diff] [blame]3963 is either zero or has the same sign as the dividend, <tt>op1</tt>), not the
3964 <i>modulo</i> operator (where the result is either zero or has the same sign
3965 as the divisor, <tt>op2</tt>) of a value.
3966 For more information about the difference,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3967 see <a href="http://mathforum.org/dr.math/problems/anne.4.28.99.html">The
3968 Math Forum</a>. For a table of how this is implemented in various languages,
3969 please see <a href="http://en.wikipedia.org/wiki/Modulo_operation">
3970 Wikipedia: modulo operation</a>.</p>
3971
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3972<p>Note that signed integer remainder and unsigned integer remainder are
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3973 distinct operations; for unsigned integer remainder, use '<tt>urem</tt>'.</p>
3974
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3975<p>Taking the remainder of a division by zero leads to undefined behavior.
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3976 Overflow also leads to undefined behavior; this is a rare case, but can
3977 occur, for example, by taking the remainder of a 32-bit division of
3978 -2147483648 by -1. (The remainder doesn't actually overflow, but this rule
3979 lets srem be implemented using instructions that return both the result of
3980 the division and the remainder.)</p>
3981
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3982<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3983<pre>
3984 &lt;result&gt; = srem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3985</pre>
3986
3987</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3988
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3989<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3990<h4>
3991 <a name="i_frem">'<tt>frem</tt>' Instruction</a>
3992</h4>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3993
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3994<div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3995
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3996<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3997<pre>
3998 &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]3999</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4000
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]4001<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4002<p>The '<tt>frem</tt>' instruction returns the remainder from the division of
4003 its two operands.</p>
4004
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]4005<h5>Arguments:</h5>
4006<p>The two arguments to the '<tt>frem</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4007 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
4008 floating point values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4009
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]4010<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4011<p>This instruction returns the <i>remainder</i> of a division. The remainder
4012 has the same sign as the dividend.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4013
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]4014<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4015<pre>
4016 &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]4017</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4018
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4019</div>
Robert Bocchino7b81c752006-02-17 21:18:08 +0000[diff] [blame]4020
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4021</div>
4022
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]4023<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4024<h3>
4025 <a name="bitwiseops">Bitwise Binary Operations</a>
4026</h3>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4027
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4028<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4029
4030<p>Bitwise binary operators are used to do various forms of bit-twiddling in a
4031 program. They are generally very efficient instructions and can commonly be
4032 strength reduced from other instructions. They require two operands of the
4033 same type, execute an operation on them, and produce a single value. The
4034 resulting value is the same type as its operands.</p>
4035
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4036<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4037<h4>
4038 <a name="i_shl">'<tt>shl</tt>' Instruction</a>
4039</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4040
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4041<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4042
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4043<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4044<pre>
Chris Lattnerf067d582011-02-07 16:40:21 +0000[diff] [blame]4045 &lt;result&gt; = shl &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
4046 &lt;result&gt; = shl nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
4047 &lt;result&gt; = shl nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
4048 &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]4049</pre>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]4050
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4051<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4052<p>The '<tt>shl</tt>' instruction returns the first operand shifted to the left
4053 a specified number of bits.</p>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]4054
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4055<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4056<p>Both arguments to the '<tt>shl</tt>' instruction must be the
4057 same <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
4058 integer type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4059
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4060<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4061<p>The value produced is <tt>op1</tt> * 2<sup><tt>op2</tt></sup> mod
4062 2<sup>n</sup>, where <tt>n</tt> is the width of the result. If <tt>op2</tt>
4063 is (statically or dynamically) negative or equal to or larger than the number
4064 of bits in <tt>op1</tt>, the result is undefined. If the arguments are
4065 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
4066 shift amount in <tt>op2</tt>.</p>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]4067
Chris Lattnerf067d582011-02-07 16:40:21 +0000[diff] [blame]4068<p>If the <tt>nuw</tt> keyword is present, then the shift produces a
4069 <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]4070 the <tt>nsw</tt> keyword is present, then the shift produces a
Chris Lattnerf067d582011-02-07 16:40:21 +0000[diff] [blame]4071 <a href="#trapvalues">trap value</a> if it shifts out any bits that disagree
4072 with the resultant sign bit. As such, NUW/NSW have the same semantics as
4073 they would if the shift were expressed as a mul instruction with the same
4074 nsw/nuw bits in (mul %op1, (shl 1, %op2)).</p>
4075
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4076<h5>Example:</h5>
4077<pre>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4078 &lt;result&gt; = shl i32 4, %var <i>; yields {i32}: 4 &lt;&lt; %var</i>
4079 &lt;result&gt; = shl i32 4, 2 <i>; yields {i32}: 16</i>
4080 &lt;result&gt; = shl i32 1, 10 <i>; yields {i32}: 1024</i>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]4081 &lt;result&gt; = shl i32 1, 32 <i>; undefined</i>
Mon P Wange9f10152008-12-09 05:46:39 +0000[diff] [blame]4082 &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]4083</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4084
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4085</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4086
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4087<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4088<h4>
4089 <a name="i_lshr">'<tt>lshr</tt>' Instruction</a>
4090</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4091
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4092<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4093
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4094<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4095<pre>
Chris Lattnerf067d582011-02-07 16:40:21 +0000[diff] [blame]4096 &lt;result&gt; = lshr &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
4097 &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]4098</pre>
4099
4100<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4101<p>The '<tt>lshr</tt>' instruction (logical shift right) returns the first
4102 operand shifted to the right a specified number of bits with zero fill.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4103
4104<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4105<p>Both arguments to the '<tt>lshr</tt>' instruction must be the same
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4106 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
4107 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4108
4109<h5>Semantics:</h5>
4110<p>This instruction always performs a logical shift right operation. The most
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4111 significant bits of the result will be filled with zero bits after the shift.
4112 If <tt>op2</tt> is (statically or dynamically) equal to or larger than the
4113 number of bits in <tt>op1</tt>, the result is undefined. If the arguments are
4114 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
4115 shift amount in <tt>op2</tt>.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4116
Chris Lattnerf067d582011-02-07 16:40:21 +0000[diff] [blame]4117<p>If the <tt>exact</tt> keyword is present, the result value of the
4118 <tt>lshr</tt> is a <a href="#trapvalues">trap value</a> if any of the bits
4119 shifted out are non-zero.</p>
4120
4121
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4122<h5>Example:</h5>
4123<pre>
4124 &lt;result&gt; = lshr i32 4, 1 <i>; yields {i32}:result = 2</i>
4125 &lt;result&gt; = lshr i32 4, 2 <i>; yields {i32}:result = 1</i>
4126 &lt;result&gt; = lshr i8 4, 3 <i>; yields {i8}:result = 0</i>
4127 &lt;result&gt; = lshr i8 -2, 1 <i>; yields {i8}:result = 0x7FFFFFFF </i>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]4128 &lt;result&gt; = lshr i32 1, 32 <i>; undefined</i>
Mon P Wange9f10152008-12-09 05:46:39 +0000[diff] [blame]4129 &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]4130</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4131
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4132</div>
4133
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]4134<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4135<h4>
4136 <a name="i_ashr">'<tt>ashr</tt>' Instruction</a>
4137</h4>
4138
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4139<div>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4140
4141<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4142<pre>
Chris Lattnerf067d582011-02-07 16:40:21 +0000[diff] [blame]4143 &lt;result&gt; = ashr &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
4144 &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]4145</pre>
4146
4147<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4148<p>The '<tt>ashr</tt>' instruction (arithmetic shift right) returns the first
4149 operand shifted to the right a specified number of bits with sign
4150 extension.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4151
4152<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4153<p>Both arguments to the '<tt>ashr</tt>' instruction must be the same
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4154 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
4155 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4156
4157<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4158<p>This instruction always performs an arithmetic shift right operation, The
4159 most significant bits of the result will be filled with the sign bit
4160 of <tt>op1</tt>. If <tt>op2</tt> is (statically or dynamically) equal to or
4161 larger than the number of bits in <tt>op1</tt>, the result is undefined. If
4162 the arguments are vectors, each vector element of <tt>op1</tt> is shifted by
4163 the corresponding shift amount in <tt>op2</tt>.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4164
Chris Lattnerf067d582011-02-07 16:40:21 +0000[diff] [blame]4165<p>If the <tt>exact</tt> keyword is present, the result value of the
4166 <tt>ashr</tt> is a <a href="#trapvalues">trap value</a> if any of the bits
4167 shifted out are non-zero.</p>
4168
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4169<h5>Example:</h5>
4170<pre>
4171 &lt;result&gt; = ashr i32 4, 1 <i>; yields {i32}:result = 2</i>
4172 &lt;result&gt; = ashr i32 4, 2 <i>; yields {i32}:result = 1</i>
4173 &lt;result&gt; = ashr i8 4, 3 <i>; yields {i8}:result = 0</i>
4174 &lt;result&gt; = ashr i8 -2, 1 <i>; yields {i8}:result = -1</i>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]4175 &lt;result&gt; = ashr i32 1, 32 <i>; undefined</i>
Mon P Wange9f10152008-12-09 05:46:39 +0000[diff] [blame]4176 &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]4177</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4178
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4179</div>
4180
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4181<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4182<h4>
4183 <a name="i_and">'<tt>and</tt>' Instruction</a>
4184</h4>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4185
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4186<div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4187
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4188<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4189<pre>
Gabor Greiffb224a22008-08-07 21:46:00 +0000[diff] [blame]4190 &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]4191</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4192
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4193<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4194<p>The '<tt>and</tt>' instruction returns the bitwise logical and of its two
4195 operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4196
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4197<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4198<p>The two arguments to the '<tt>and</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4199 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
4200 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4201
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4202<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4203<p>The truth table used for the '<tt>and</tt>' instruction is:</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4204
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4205<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4206 <tbody>
4207 <tr>
4208 <td>In0</td>
4209 <td>In1</td>
4210 <td>Out</td>
4211 </tr>
4212 <tr>
4213 <td>0</td>
4214 <td>0</td>
4215 <td>0</td>
4216 </tr>
4217 <tr>
4218 <td>0</td>
4219 <td>1</td>
4220 <td>0</td>
4221 </tr>
4222 <tr>
4223 <td>1</td>
4224 <td>0</td>
4225 <td>0</td>
4226 </tr>
4227 <tr>
4228 <td>1</td>
4229 <td>1</td>
4230 <td>1</td>
4231 </tr>
4232 </tbody>
4233</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4234
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4235<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4236<pre>
4237 &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]4238 &lt;result&gt; = and i32 15, 40 <i>; yields {i32}:result = 8</i>
4239 &lt;result&gt; = and i32 4, 8 <i>; yields {i32}:result = 0</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4240</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4241</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4242<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4243<h4>
4244 <a name="i_or">'<tt>or</tt>' Instruction</a>
4245</h4>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4246
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4247<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4248
4249<h5>Syntax:</h5>
4250<pre>
4251 &lt;result&gt; = or &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
4252</pre>
4253
4254<h5>Overview:</h5>
4255<p>The '<tt>or</tt>' instruction returns the bitwise logical inclusive or of its
4256 two operands.</p>
4257
4258<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4259<p>The two arguments to the '<tt>or</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4260 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
4261 values. Both arguments must have identical types.</p>
4262
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4263<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4264<p>The truth table used for the '<tt>or</tt>' instruction is:</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4265
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4266<table border="1" cellspacing="0" cellpadding="4">
4267 <tbody>
4268 <tr>
4269 <td>In0</td>
4270 <td>In1</td>
4271 <td>Out</td>
4272 </tr>
4273 <tr>
4274 <td>0</td>
4275 <td>0</td>
4276 <td>0</td>
4277 </tr>
4278 <tr>
4279 <td>0</td>
4280 <td>1</td>
4281 <td>1</td>
4282 </tr>
4283 <tr>
4284 <td>1</td>
4285 <td>0</td>
4286 <td>1</td>
4287 </tr>
4288 <tr>
4289 <td>1</td>
4290 <td>1</td>
4291 <td>1</td>
4292 </tr>
4293 </tbody>
4294</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4295
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4296<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4297<pre>
4298 &lt;result&gt; = or i32 4, %var <i>; yields {i32}:result = 4 | %var</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4299 &lt;result&gt; = or i32 15, 40 <i>; yields {i32}:result = 47</i>
4300 &lt;result&gt; = or i32 4, 8 <i>; yields {i32}:result = 12</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4301</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4302
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4303</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4304
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4305<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4306<h4>
4307 <a name="i_xor">'<tt>xor</tt>' Instruction</a>
4308</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4309
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4310<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4311
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4312<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4313<pre>
4314 &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]4315</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4316
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4317<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4318<p>The '<tt>xor</tt>' instruction returns the bitwise logical exclusive or of
4319 its two operands. The <tt>xor</tt> is used to implement the "one's
4320 complement" operation, which is the "~" operator in C.</p>
4321
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4322<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4323<p>The two arguments to the '<tt>xor</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4324 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
4325 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4326
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4327<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4328<p>The truth table used for the '<tt>xor</tt>' instruction is:</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4329
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4330<table border="1" cellspacing="0" cellpadding="4">
4331 <tbody>
4332 <tr>
4333 <td>In0</td>
4334 <td>In1</td>
4335 <td>Out</td>
4336 </tr>
4337 <tr>
4338 <td>0</td>
4339 <td>0</td>
4340 <td>0</td>
4341 </tr>
4342 <tr>
4343 <td>0</td>
4344 <td>1</td>
4345 <td>1</td>
4346 </tr>
4347 <tr>
4348 <td>1</td>
4349 <td>0</td>
4350 <td>1</td>
4351 </tr>
4352 <tr>
4353 <td>1</td>
4354 <td>1</td>
4355 <td>0</td>
4356 </tr>
4357 </tbody>
4358</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4359
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4360<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4361<pre>
4362 &lt;result&gt; = xor i32 4, %var <i>; yields {i32}:result = 4 ^ %var</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4363 &lt;result&gt; = xor i32 15, 40 <i>; yields {i32}:result = 39</i>
4364 &lt;result&gt; = xor i32 4, 8 <i>; yields {i32}:result = 12</i>
4365 &lt;result&gt; = xor i32 %V, -1 <i>; yields {i32}:result = ~%V</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4366</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4367
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4368</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4369
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4370</div>
4371
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4372<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4373<h3>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4374 <a name="vectorops">Vector Operations</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4375</h3>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4376
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4377<div>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4378
4379<p>LLVM supports several instructions to represent vector operations in a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4380 target-independent manner. These instructions cover the element-access and
4381 vector-specific operations needed to process vectors effectively. While LLVM
4382 does directly support these vector operations, many sophisticated algorithms
4383 will want to use target-specific intrinsics to take full advantage of a
4384 specific target.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4385
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4386<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4387<h4>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4388 <a name="i_extractelement">'<tt>extractelement</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4389</h4>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4390
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4391<div>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4392
4393<h5>Syntax:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4394<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4395 &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]4396</pre>
4397
4398<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4399<p>The '<tt>extractelement</tt>' instruction extracts a single scalar element
4400 from a vector at a specified index.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4401
4402
4403<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4404<p>The first operand of an '<tt>extractelement</tt>' instruction is a value
4405 of <a href="#t_vector">vector</a> type. The second operand is an index
4406 indicating the position from which to extract the element. The index may be
4407 a variable.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4408
4409<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4410<p>The result is a scalar of the same type as the element type of
4411 <tt>val</tt>. Its value is the value at position <tt>idx</tt> of
4412 <tt>val</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
4413 results are undefined.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4414
4415<h5>Example:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4416<pre>
Gabor Greifa5b6f452009-10-28 13:14:50 +0000[diff] [blame]4417 &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]4418</pre>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4419
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4420</div>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4421
4422<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4423<h4>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4424 <a name="i_insertelement">'<tt>insertelement</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4425</h4>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4426
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4427<div>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4428
4429<h5>Syntax:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4430<pre>
Dan Gohmanf3480b92008-05-12 23:38:42 +0000[diff] [blame]4431 &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]4432</pre>
4433
4434<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4435<p>The '<tt>insertelement</tt>' instruction inserts a scalar element into a
4436 vector at a specified index.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4437
4438<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4439<p>The first operand of an '<tt>insertelement</tt>' instruction is a value
4440 of <a href="#t_vector">vector</a> type. The second operand is a scalar value
4441 whose type must equal the element type of the first operand. The third
4442 operand is an index indicating the position at which to insert the value.
4443 The index may be a variable.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4444
4445<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4446<p>The result is a vector of the same type as <tt>val</tt>. Its element values
4447 are those of <tt>val</tt> except at position <tt>idx</tt>, where it gets the
4448 value <tt>elt</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
4449 results are undefined.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4450
4451<h5>Example:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4452<pre>
Gabor Greifa5b6f452009-10-28 13:14:50 +0000[diff] [blame]4453 &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]4454</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4455
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4456</div>
4457
4458<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4459<h4>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4460 <a name="i_shufflevector">'<tt>shufflevector</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4461</h4>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4462
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4463<div>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4464
4465<h5>Syntax:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4466<pre>
Mon P Wangaeb06d22008-11-10 04:46:22 +0000[diff] [blame]4467 &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]4468</pre>
4469
4470<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4471<p>The '<tt>shufflevector</tt>' instruction constructs a permutation of elements
4472 from two input vectors, returning a vector with the same element type as the
4473 input and length that is the same as the shuffle mask.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4474
4475<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4476<p>The first two operands of a '<tt>shufflevector</tt>' instruction are vectors
4477 with types that match each other. The third argument is a shuffle mask whose
4478 element type is always 'i32'. The result of the instruction is a vector
4479 whose length is the same as the shuffle mask and whose element type is the
4480 same as the element type of the first two operands.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4481
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4482<p>The shuffle mask operand is required to be a constant vector with either
4483 constant integer or undef values.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4484
4485<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4486<p>The elements of the two input vectors are numbered from left to right across
4487 both of the vectors. The shuffle mask operand specifies, for each element of
4488 the result vector, which element of the two input vectors the result element
4489 gets. The element selector may be undef (meaning "don't care") and the
4490 second operand may be undef if performing a shuffle from only one vector.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4491
4492<h5>Example:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4493<pre>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4494 &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]4495 &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]4496 &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]4497 &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]4498 &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]4499 &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]4500 &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]4501 &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]4502</pre>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4503
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4504</div>
Tanya Lattner09474292006-04-14 19:24:33 +0000[diff] [blame]4505
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4506</div>
4507
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4508<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4509<h3>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4510 <a name="aggregateops">Aggregate Operations</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4511</h3>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4512
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4513<div>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4514
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4515<p>LLVM supports several instructions for working with
4516 <a href="#t_aggregate">aggregate</a> values.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4517
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4518<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4519<h4>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4520 <a name="i_extractvalue">'<tt>extractvalue</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4521</h4>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4522
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4523<div>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4524
4525<h5>Syntax:</h5>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4526<pre>
4527 &lt;result&gt; = extractvalue &lt;aggregate type&gt; &lt;val&gt;, &lt;idx&gt;{, &lt;idx&gt;}*
4528</pre>
4529
4530<h5>Overview:</h5>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4531<p>The '<tt>extractvalue</tt>' instruction extracts the value of a member field
4532 from an <a href="#t_aggregate">aggregate</a> value.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4533
4534<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4535<p>The first operand of an '<tt>extractvalue</tt>' instruction is a value
Chris Lattner61c70e92010-08-28 04:09:24 +0000[diff] [blame]4536 of <a href="#t_struct">struct</a> or
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4537 <a href="#t_array">array</a> type. The operands are constant indices to
4538 specify which value to extract in a similar manner as indices in a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4539 '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
Frits van Bommel13242892010-12-05 20:54:38 +0000[diff] [blame]4540 <p>The major differences to <tt>getelementptr</tt> indexing are:</p>
4541 <ul>
4542 <li>Since the value being indexed is not a pointer, the first index is
4543 omitted and assumed to be zero.</li>
4544 <li>At least one index must be specified.</li>
4545 <li>Not only struct indices but also array indices must be in
4546 bounds.</li>
4547 </ul>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4548
4549<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4550<p>The result is the value at the position in the aggregate specified by the
4551 index operands.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4552
4553<h5>Example:</h5>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4554<pre>
Gabor Greifa5b6f452009-10-28 13:14:50 +0000[diff] [blame]4555 &lt;result&gt; = extractvalue {i32, float} %agg, 0 <i>; yields i32</i>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4556</pre>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4557
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4558</div>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4559
4560<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4561<h4>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4562 <a name="i_insertvalue">'<tt>insertvalue</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4563</h4>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4564
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4565<div>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4566
4567<h5>Syntax:</h5>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4568<pre>
Bill Wendling194229e2011-07-26 20:42:28 +0000[diff] [blame]4569 &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]4570</pre>
4571
4572<h5>Overview:</h5>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4573<p>The '<tt>insertvalue</tt>' instruction inserts a value into a member field
4574 in an <a href="#t_aggregate">aggregate</a> value.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4575
4576<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4577<p>The first operand of an '<tt>insertvalue</tt>' instruction is a value
Chris Lattner61c70e92010-08-28 04:09:24 +0000[diff] [blame]4578 of <a href="#t_struct">struct</a> or
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4579 <a href="#t_array">array</a> type. The second operand is a first-class
4580 value to insert. The following operands are constant indices indicating
4581 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]4582 '<tt><a href="#i_extractvalue">extractvalue</a></tt>' instruction. The
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4583 value to insert must have the same type as the value identified by the
4584 indices.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4585
4586<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4587<p>The result is an aggregate of the same type as <tt>val</tt>. Its value is
4588 that of <tt>val</tt> except that the value at the position specified by the
4589 indices is that of <tt>elt</tt>.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4590
4591<h5>Example:</h5>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4592<pre>
Chris Lattner8645d1a2011-05-22 07:18:08 +0000[diff] [blame]4593 %agg1 = insertvalue {i32, float} undef, i32 1, 0 <i>; yields {i32 1, float undef}</i>
4594 %agg2 = insertvalue {i32, float} %agg1, float %val, 1 <i>; yields {i32 1, float %val}</i>
4595 %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]4596</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4597
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4598</div>
4599
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4600</div>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4601
4602<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4603<h3>
Chris Lattner884a9702006-08-15 00:45:58 +0000[diff] [blame]4604 <a name="memoryops">Memory Access and Addressing Operations</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4605</h3>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4606
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4607<div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4608
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4609<p>A key design point of an SSA-based representation is how it represents
4610 memory. In LLVM, no memory locations are in SSA form, which makes things
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]4611 very simple. This section describes how to read, write, and allocate
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4612 memory in LLVM.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4613
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4614<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4615<h4>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4616 <a name="i_alloca">'<tt>alloca</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4617</h4>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4618
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4619<div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4620
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4621<h5>Syntax:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4622<pre>
Dan Gohmanf75a7d32010-05-28 01:14:11 +0000[diff] [blame]4623 &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]4624</pre>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4625
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4626<h5>Overview:</h5>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]4627<p>The '<tt>alloca</tt>' instruction allocates memory on the stack frame of the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4628 currently executing function, to be automatically released when this function
4629 returns to its caller. The object is always allocated in the generic address
4630 space (address space zero).</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4631
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4632<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4633<p>The '<tt>alloca</tt>' instruction
4634 allocates <tt>sizeof(&lt;type&gt;)*NumElements</tt> bytes of memory on the
4635 runtime stack, returning a pointer of the appropriate type to the program.
4636 If "NumElements" is specified, it is the number of elements allocated,
4637 otherwise "NumElements" is defaulted to be one. If a constant alignment is
4638 specified, the value result of the allocation is guaranteed to be aligned to
4639 at least that boundary. If not specified, or if zero, the target can choose
4640 to align the allocation on any convenient boundary compatible with the
4641 type.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4642
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4643<p>'<tt>type</tt>' may be any sized type.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4644
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4645<h5>Semantics:</h5>
Bill Wendling871eb0a2009-05-08 20:49:29 +0000[diff] [blame]4646<p>Memory is allocated; a pointer is returned. The operation is undefined if
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4647 there is insufficient stack space for the allocation. '<tt>alloca</tt>'d
4648 memory is automatically released when the function returns. The
4649 '<tt>alloca</tt>' instruction is commonly used to represent automatic
4650 variables that must have an address available. When the function returns
4651 (either with the <tt><a href="#i_ret">ret</a></tt>
4652 or <tt><a href="#i_unwind">unwind</a></tt> instructions), the memory is
4653 reclaimed. Allocating zero bytes is legal, but the result is undefined.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4654
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4655<h5>Example:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4656<pre>
Dan Gohman81e21672009-01-04 23:49:44 +0000[diff] [blame]4657 %ptr = alloca i32 <i>; yields {i32*}:ptr</i>
4658 %ptr = alloca i32, i32 4 <i>; yields {i32*}:ptr</i>
4659 %ptr = alloca i32, i32 4, align 1024 <i>; yields {i32*}:ptr</i>
4660 %ptr = alloca i32, align 1024 <i>; yields {i32*}:ptr</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4661</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4662
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4663</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4664
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4665<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4666<h4>
4667 <a name="i_load">'<tt>load</tt>' Instruction</a>
4668</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4669
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4670<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4671
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4672<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4673<pre>
Eli Friedmanf03bb262011-08-12 22:50:01 +0000[diff] [blame]4674 &lt;result&gt; = load [volatile] &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;][, !nontemporal !&lt;index&gt;]
4675 &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]4676 !&lt;index&gt; = !{ i32 1 }
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4677</pre>
4678
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4679<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4680<p>The '<tt>load</tt>' instruction is used to read from memory.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4681
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4682<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4683<p>The argument to the '<tt>load</tt>' instruction specifies the memory address
4684 from which to load. The pointer must point to
4685 a <a href="#t_firstclass">first class</a> type. If the <tt>load</tt> is
4686 marked as <tt>volatile</tt>, then the optimizer is not allowed to modify the
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]4687 number or order of execution of this <tt>load</tt> with other <a
4688 href="#volatile">volatile operations</a>.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4689
Eli Friedman21006d42011-08-09 23:02:53 +0000[diff] [blame]4690<p>If the <code>load</code> is marked as <code>atomic</code>, it takes an extra
4691 <a href="#ordering">ordering</a> and optional <code>singlethread</code>
4692 argument. The <code>release</code> and <code>acq_rel</code> orderings are
4693 not valid on <code>load</code> instructions. Atomic loads produce <a
4694 href="#memorymodel">defined</a> results when they may see multiple atomic
4695 stores. The type of the pointee must be an integer type whose bit width
4696 is a power of two greater than or equal to eight and less than or equal
4697 to a target-specific size limit. <code>align</code> must be explicitly
4698 specified on atomic loads, and the load has undefined behavior if the
4699 alignment is not set to a value which is at least the size in bytes of
4700 the pointee. <code>!nontemporal</code> does not have any defined semantics
4701 for atomic loads.</p>
4702
Bill Wendling7c78dbb2010-02-25 21:23:24 +0000[diff] [blame]4703<p>The optional constant <tt>align</tt> argument specifies the alignment of the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4704 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]4705 omitted <tt>align</tt> argument means that the operation has the preferential
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4706 alignment for the target. It is the responsibility of the code emitter to
4707 ensure that the alignment information is correct. Overestimating the
Bill Wendling7c78dbb2010-02-25 21:23:24 +0000[diff] [blame]4708 alignment results in undefined behavior. Underestimating the alignment may
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4709 produce less efficient code. An alignment of 1 is always safe.</p>
4710
Bill Wendling7c78dbb2010-02-25 21:23:24 +0000[diff] [blame]4711<p>The optional <tt>!nontemporal</tt> metadata must reference a single
4712 metatadata name &lt;index&gt; corresponding to a metadata node with
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]4713 one <tt>i32</tt> entry of value 1. The existence of
Bill Wendling7c78dbb2010-02-25 21:23:24 +0000[diff] [blame]4714 the <tt>!nontemporal</tt> metatadata on the instruction tells the optimizer
4715 and code generator that this load is not expected to be reused in the cache.
4716 The code generator may select special instructions to save cache bandwidth,
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]4717 such as the <tt>MOVNT</tt> instruction on x86.</p>
David Greene8939b0d2010-02-16 20:50:18 +0000[diff] [blame]4718
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4719<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4720<p>The location of memory pointed to is loaded. If the value being loaded is of
4721 scalar type then the number of bytes read does not exceed the minimum number
4722 of bytes needed to hold all bits of the type. For example, loading an
4723 <tt>i24</tt> reads at most three bytes. When loading a value of a type like
4724 <tt>i20</tt> with a size that is not an integral number of bytes, the result
4725 is undefined if the value was not originally written using a store of the
4726 same type.</p>
4727
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4728<h5>Examples:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4729<pre>
4730 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
4731 <a href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4732 %val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4733</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4734
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4735</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4736
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4737<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4738<h4>
4739 <a name="i_store">'<tt>store</tt>' Instruction</a>
4740</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4741
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4742<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4743
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4744<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4745<pre>
Eli Friedmanf03bb262011-08-12 22:50:01 +0000[diff] [blame]4746 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>
4747 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]4748</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4749
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4750<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4751<p>The '<tt>store</tt>' instruction is used to write to memory.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4752
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4753<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4754<p>There are two arguments to the '<tt>store</tt>' instruction: a value to store
4755 and an address at which to store it. The type of the
4756 '<tt>&lt;pointer&gt;</tt>' operand must be a pointer to
4757 the <a href="#t_firstclass">first class</a> type of the
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]4758 '<tt>&lt;value&gt;</tt>' operand. If the <tt>store</tt> is marked as
4759 <tt>volatile</tt>, then the optimizer is not allowed to modify the number or
4760 order of execution of this <tt>store</tt> with other <a
4761 href="#volatile">volatile operations</a>.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4762
Eli Friedman21006d42011-08-09 23:02:53 +0000[diff] [blame]4763<p>If the <code>store</code> is marked as <code>atomic</code>, it takes an extra
4764 <a href="#ordering">ordering</a> and optional <code>singlethread</code>
4765 argument. The <code>acquire</code> and <code>acq_rel</code> orderings aren't
4766 valid on <code>store</code> instructions. Atomic loads produce <a
4767 href="#memorymodel">defined</a> results when they may see multiple atomic
4768 stores. The type of the pointee must be an integer type whose bit width
4769 is a power of two greater than or equal to eight and less than or equal
4770 to a target-specific size limit. <code>align</code> must be explicitly
4771 specified on atomic stores, and the store has undefined behavior if the
4772 alignment is not set to a value which is at least the size in bytes of
4773 the pointee. <code>!nontemporal</code> does not have any defined semantics
4774 for atomic stores.</p>
4775
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4776<p>The optional constant "align" argument specifies the alignment of the
4777 operation (that is, the alignment of the memory address). A value of 0 or an
4778 omitted "align" argument means that the operation has the preferential
4779 alignment for the target. It is the responsibility of the code emitter to
4780 ensure that the alignment information is correct. Overestimating the
4781 alignment results in an undefined behavior. Underestimating the alignment may
4782 produce less efficient code. An alignment of 1 is always safe.</p>
4783
David Greene8939b0d2010-02-16 20:50:18 +0000[diff] [blame]4784<p>The optional !nontemporal metadata must reference a single metatadata
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]4785 name &lt;index&gt; corresponding to a metadata node with one i32 entry of
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]4786 value 1. The existence of the !nontemporal metatadata on the
David Greene8939b0d2010-02-16 20:50:18 +0000[diff] [blame]4787 instruction tells the optimizer and code generator that this load is
4788 not expected to be reused in the cache. The code generator may
4789 select special instructions to save cache bandwidth, such as the
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]4790 MOVNT instruction on x86.</p>
David Greene8939b0d2010-02-16 20:50:18 +0000[diff] [blame]4791
4792
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4793<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4794<p>The contents of memory are updated to contain '<tt>&lt;value&gt;</tt>' at the
4795 location specified by the '<tt>&lt;pointer&gt;</tt>' operand. If
4796 '<tt>&lt;value&gt;</tt>' is of scalar type then the number of bytes written
4797 does not exceed the minimum number of bytes needed to hold all bits of the
4798 type. For example, storing an <tt>i24</tt> writes at most three bytes. When
4799 writing a value of a type like <tt>i20</tt> with a size that is not an
4800 integral number of bytes, it is unspecified what happens to the extra bits
4801 that do not belong to the type, but they will typically be overwritten.</p>
4802
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4803<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4804<pre>
4805 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Bill Wendling8c6c72d2007-10-22 05:10:05 +0000[diff] [blame]4806 store i32 3, i32* %ptr <i>; yields {void}</i>
4807 %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]4808</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4809
Reid Spencer47ce1792006-11-09 21:15:49 +0000[diff] [blame]4810</div>
4811
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4812<!-- _______________________________________________________________________ -->
NAKAMURA Takumib5bb29c2011-08-12 06:17:17 +0000[diff] [blame]4813<h4>
4814<a name="i_fence">'<tt>fence</tt>' Instruction</a>
4815</h4>
Eli Friedman47f35132011-07-25 23:16:38 +0000[diff] [blame]4816
NAKAMURA Takumib5bb29c2011-08-12 06:17:17 +0000[diff] [blame]4817<div>
Eli Friedman47f35132011-07-25 23:16:38 +0000[diff] [blame]4818
4819<h5>Syntax:</h5>
4820<pre>
4821 fence [singlethread] &lt;ordering&gt; <i>; yields {void}</i>
4822</pre>
4823
4824<h5>Overview:</h5>
4825<p>The '<tt>fence</tt>' instruction is used to introduce happens-before edges
4826between operations.</p>
4827
4828<h5>Arguments:</h5> <p>'<code>fence</code>' instructions take an <a
4829href="#ordering">ordering</a> argument which defines what
4830<i>synchronizes-with</i> edges they add. They can only be given
4831<code>acquire</code>, <code>release</code>, <code>acq_rel</code>, and
4832<code>seq_cst</code> orderings.</p>
4833
4834<h5>Semantics:</h5>
4835<p>A fence <var>A</var> which has (at least) <code>release</code> ordering
4836semantics <i>synchronizes with</i> a fence <var>B</var> with (at least)
4837<code>acquire</code> ordering semantics if and only if there exist atomic
4838operations <var>X</var> and <var>Y</var>, both operating on some atomic object
4839<var>M</var>, such that <var>A</var> is sequenced before <var>X</var>,
4840<var>X</var> modifies <var>M</var> (either directly or through some side effect
4841of a sequence headed by <var>X</var>), <var>Y</var> is sequenced before
4842<var>B</var>, and <var>Y</var> observes <var>M</var>. This provides a
4843<i>happens-before</i> dependency between <var>A</var> and <var>B</var>. Rather
4844than an explicit <code>fence</code>, one (but not both) of the atomic operations
4845<var>X</var> or <var>Y</var> might provide a <code>release</code> or
4846<code>acquire</code> (resp.) ordering constraint and still
4847<i>synchronize-with</i> the explicit <code>fence</code> and establish the
4848<i>happens-before</i> edge.</p>
4849
4850<p>A <code>fence</code> which has <code>seq_cst</code> ordering, in addition to
4851having both <code>acquire</code> and <code>release</code> semantics specified
4852above, participates in the global program order of other <code>seq_cst</code>
4853operations and/or fences.</p>
4854
4855<p>The optional "<a href="#singlethread"><code>singlethread</code></a>" argument
4856specifies that the fence only synchronizes with other fences in the same
4857thread. (This is useful for interacting with signal handlers.)</p>
4858
Eli Friedman47f35132011-07-25 23:16:38 +0000[diff] [blame]4859<h5>Example:</h5>
4860<pre>
4861 fence acquire <i>; yields {void}</i>
4862 fence singlethread seq_cst <i>; yields {void}</i>
4863</pre>
4864
4865</div>
4866
4867<!-- _______________________________________________________________________ -->
NAKAMURA Takumib5bb29c2011-08-12 06:17:17 +0000[diff] [blame]4868<h4>
4869<a name="i_cmpxchg">'<tt>cmpxchg</tt>' Instruction</a>
4870</h4>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]4871
NAKAMURA Takumib5bb29c2011-08-12 06:17:17 +0000[diff] [blame]4872<div>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]4873
4874<h5>Syntax:</h5>
4875<pre>
Eli Friedmanf03bb262011-08-12 22:50:01 +0000[diff] [blame]4876 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]4877</pre>
4878
4879<h5>Overview:</h5>
4880<p>The '<tt>cmpxchg</tt>' instruction is used to atomically modify memory.
4881It loads a value in memory and compares it to a given value. If they are
4882equal, it stores a new value into the memory.</p>
4883
4884<h5>Arguments:</h5>
4885<p>There are three arguments to the '<code>cmpxchg</code>' instruction: an
4886address to operate on, a value to compare to the value currently be at that
4887address, and a new value to place at that address if the compared values are
4888equal. The type of '<var>&lt;cmp&gt;</var>' must be an integer type whose
4889bit width is a power of two greater than or equal to eight and less than
4890or equal to a target-specific size limit. '<var>&lt;cmp&gt;</var>' and
4891'<var>&lt;new&gt;</var>' must have the same type, and the type of
4892'<var>&lt;pointer&gt;</var>' must be a pointer to that type. If the
4893<code>cmpxchg</code> is marked as <code>volatile</code>, then the
4894optimizer is not allowed to modify the number or order of execution
4895of this <code>cmpxchg</code> with other <a href="#volatile">volatile
4896operations</a>.</p>
4897
4898<!-- FIXME: Extend allowed types. -->
4899
4900<p>The <a href="#ordering"><var>ordering</var></a> argument specifies how this
4901<code>cmpxchg</code> synchronizes with other atomic operations.</p>
4902
4903<p>The optional "<code>singlethread</code>" argument declares that the
4904<code>cmpxchg</code> is only atomic with respect to code (usually signal
4905handlers) running in the same thread as the <code>cmpxchg</code>. Otherwise the
4906cmpxchg is atomic with respect to all other code in the system.</p>
4907
4908<p>The pointer passed into cmpxchg must have alignment greater than or equal to
4909the size in memory of the operand.
4910
4911<h5>Semantics:</h5>
4912<p>The contents of memory at the location specified by the
4913'<tt>&lt;pointer&gt;</tt>' operand is read and compared to
4914'<tt>&lt;cmp&gt;</tt>'; if the read value is the equal,
4915'<tt>&lt;new&gt;</tt>' is written. The original value at the location
4916is returned.
4917
4918<p>A successful <code>cmpxchg</code> is a read-modify-write instruction for the
4919purpose of identifying <a href="#release_sequence">release sequences</a>. A
4920failed <code>cmpxchg</code> is equivalent to an atomic load with an ordering
4921parameter determined by dropping any <code>release</code> part of the
4922<code>cmpxchg</code>'s ordering.</p>
4923
4924<!--
4925FIXME: Is compare_exchange_weak() necessary? (Consider after we've done
4926optimization work on ARM.)
4927
4928FIXME: Is a weaker ordering constraint on failure helpful in practice?
4929-->
4930
4931<h5>Example:</h5>
4932<pre>
4933entry:
4934 %orig = atomic <a href="#i_load">load</a> i32* %ptr unordered <i>; yields {i32}</i>
4935 <a href="#i_br">br</a> label %loop
4936
4937loop:
4938 %cmp = <a href="#i_phi">phi</a> i32 [ %orig, %entry ], [%old, %loop]
4939 %squared = <a href="#i_mul">mul</a> i32 %cmp, %cmp
4940 %old = cmpxchg i32* %ptr, i32 %cmp, i32 %squared <i>; yields {i32}</i>
4941 %success = <a href="#i_icmp">icmp</a> eq i32 %cmp, %old
4942 <a href="#i_br">br</a> i1 %success, label %done, label %loop
4943
4944done:
4945 ...
4946</pre>
4947
4948</div>
4949
4950<!-- _______________________________________________________________________ -->
NAKAMURA Takumib5bb29c2011-08-12 06:17:17 +0000[diff] [blame]4951<h4>
4952<a name="i_atomicrmw">'<tt>atomicrmw</tt>' Instruction</a>
4953</h4>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]4954
NAKAMURA Takumib5bb29c2011-08-12 06:17:17 +0000[diff] [blame]4955<div>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]4956
4957<h5>Syntax:</h5>
4958<pre>
Eli Friedmanf03bb262011-08-12 22:50:01 +0000[diff] [blame]4959 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]4960</pre>
4961
4962<h5>Overview:</h5>
4963<p>The '<tt>atomicrmw</tt>' instruction is used to atomically modify memory.</p>
4964
4965<h5>Arguments:</h5>
4966<p>There are three arguments to the '<code>atomicrmw</code>' instruction: an
4967operation to apply, an address whose value to modify, an argument to the
4968operation. The operation must be one of the following keywords:</p>
4969<ul>
4970 <li>xchg</li>
4971 <li>add</li>
4972 <li>sub</li>
4973 <li>and</li>
4974 <li>nand</li>
4975 <li>or</li>
4976 <li>xor</li>
4977 <li>max</li>
4978 <li>min</li>
4979 <li>umax</li>
4980 <li>umin</li>
4981</ul>
4982
4983<p>The type of '<var>&lt;value&gt;</var>' must be an integer type whose
4984bit width is a power of two greater than or equal to eight and less than
4985or equal to a target-specific size limit. The type of the
4986'<code>&lt;pointer&gt;</code>' operand must be a pointer to that type.
4987If the <code>atomicrmw</code> is marked as <code>volatile</code>, then the
4988optimizer is not allowed to modify the number or order of execution of this
4989<code>atomicrmw</code> with other <a href="#volatile">volatile
4990 operations</a>.</p>
4991
4992<!-- FIXME: Extend allowed types. -->
4993
4994<h5>Semantics:</h5>
4995<p>The contents of memory at the location specified by the
4996'<tt>&lt;pointer&gt;</tt>' operand are atomically read, modified, and written
4997back. The original value at the location is returned. The modification is
4998specified by the <var>operation</var> argument:</p>
4999
5000<ul>
5001 <li>xchg: <code>*ptr = val</code></li>
5002 <li>add: <code>*ptr = *ptr + val</code></li>
5003 <li>sub: <code>*ptr = *ptr - val</code></li>
5004 <li>and: <code>*ptr = *ptr &amp; val</code></li>
5005 <li>nand: <code>*ptr = ~(*ptr &amp; val)</code></li>
5006 <li>or: <code>*ptr = *ptr | val</code></li>
5007 <li>xor: <code>*ptr = *ptr ^ val</code></li>
5008 <li>max: <code>*ptr = *ptr &gt; val ? *ptr : val</code> (using a signed comparison)</li>
5009 <li>min: <code>*ptr = *ptr &lt; val ? *ptr : val</code> (using a signed comparison)</li>
5010 <li>umax: <code>*ptr = *ptr &gt; val ? *ptr : val</code> (using an unsigned comparison)</li>
5011 <li>umin: <code>*ptr = *ptr &lt; val ? *ptr : val</code> (using an unsigned comparison)</li>
5012</ul>
5013
5014<h5>Example:</h5>
5015<pre>
5016 %old = atomicrmw add i32* %ptr, i32 1 acquire <i>; yields {i32}</i>
5017</pre>
5018
5019</div>
5020
5021<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5022<h4>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5023 <a name="i_getelementptr">'<tt>getelementptr</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5024</h4>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5025
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5026<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5027
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]5028<h5>Syntax:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5029<pre>
Matthijs Kooijmane49d0bc2008-10-13 13:44:15 +0000[diff] [blame]5030 &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]5031 &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]5032</pre>
5033
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]5034<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5035<p>The '<tt>getelementptr</tt>' instruction is used to get the address of a
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]5036 subelement of an <a href="#t_aggregate">aggregate</a> data structure.
5037 It performs address calculation only and does not access memory.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5038
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]5039<h5>Arguments:</h5>
Matthijs Kooijmane49d0bc2008-10-13 13:44:15 +0000[diff] [blame]5040<p>The first argument is always a pointer, and forms the basis of the
Chris Lattnerc8eef442009-07-29 06:44:13 +0000[diff] [blame]5041 calculation. The remaining arguments are indices that indicate which of the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5042 elements of the aggregate object are indexed. The interpretation of each
5043 index is dependent on the type being indexed into. The first index always
5044 indexes the pointer value given as the first argument, the second index
5045 indexes a value of the type pointed to (not necessarily the value directly
5046 pointed to, since the first index can be non-zero), etc. The first type
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]5047 indexed into must be a pointer value, subsequent types can be arrays,
Chris Lattner61c70e92010-08-28 04:09:24 +0000[diff] [blame]5048 vectors, and structs. Note that subsequent types being indexed into
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]5049 can never be pointers, since that would require loading the pointer before
5050 continuing calculation.</p>
Matthijs Kooijmane49d0bc2008-10-13 13:44:15 +0000[diff] [blame]5051
5052<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]5053 When indexing into a (optionally packed) structure, only <tt>i32</tt>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]5054 integer <b>constants</b> are allowed. When indexing into an array, pointer
5055 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]5056 constant. These integers are treated as signed values where relevant.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5057
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5058<p>For example, let's consider a C code fragment and how it gets compiled to
5059 LLVM:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5060
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]5061<pre class="doc_code">
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]5062struct RT {
5063 char A;
Chris Lattnercabc8462007-05-29 15:43:56 +0000[diff] [blame]5064 int B[10][20];
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]5065 char C;
5066};
5067struct ST {
Chris Lattnercabc8462007-05-29 15:43:56 +0000[diff] [blame]5068 int X;
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]5069 double Y;
5070 struct RT Z;
5071};
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5072
Chris Lattnercabc8462007-05-29 15:43:56 +0000[diff] [blame]5073int *foo(struct ST *s) {
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]5074 return &amp;s[1].Z.B[5][13];
5075}
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5076</pre>
5077
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5078<p>The LLVM code generated by the GCC frontend is:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5079
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]5080<pre class="doc_code">
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]5081%RT = <a href="#namedtypes">type</a> { i8 , [10 x [20 x i32]], i8 }
5082%ST = <a href="#namedtypes">type</a> { i32, double, %RT }
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5083
Dan Gohman4df605b2009-07-25 02:23:48 +0000[diff] [blame]5084define i32* @foo(%ST* %s) {
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]5085entry:
5086 %reg = getelementptr %ST* %s, i32 1, i32 2, i32 1, i32 5, i32 13
5087 ret i32* %reg
5088}
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5089</pre>
5090
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]5091<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5092<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]5093 type, which is a pointer, yielding a '<tt>%ST</tt>' = '<tt>{ i32, double, %RT
5094 }</tt>' type, a structure. The second index indexes into the third element
5095 of the structure, yielding a '<tt>%RT</tt>' = '<tt>{ i8 , [10 x [20 x i32]],
5096 i8 }</tt>' type, another structure. The third index indexes into the second
5097 element of the structure, yielding a '<tt>[10 x [20 x i32]]</tt>' type, an
5098 array. The two dimensions of the array are subscripted into, yielding an
5099 '<tt>i32</tt>' type. The '<tt>getelementptr</tt>' instruction returns a
5100 pointer to this element, thus computing a value of '<tt>i32*</tt>' type.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5101
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5102<p>Note that it is perfectly legal to index partially through a structure,
5103 returning a pointer to an inner element. Because of this, the LLVM code for
5104 the given testcase is equivalent to:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5105
5106<pre>
Dan Gohman4df605b2009-07-25 02:23:48 +0000[diff] [blame]5107 define i32* @foo(%ST* %s) {
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5108 %t1 = getelementptr %ST* %s, i32 1 <i>; yields %ST*:%t1</i>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]5109 %t2 = getelementptr %ST* %t1, i32 0, i32 2 <i>; yields %RT*:%t2</i>
5110 %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]5111 %t4 = getelementptr [10 x [20 x i32]]* %t3, i32 0, i32 5 <i>; yields [20 x i32]*:%t4</i>
5112 %t5 = getelementptr [20 x i32]* %t4, i32 0, i32 13 <i>; yields i32*:%t5</i>
5113 ret i32* %t5
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5114 }
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]5115</pre>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]5116
Dan Gohmandd8004d2009-07-27 21:53:46 +0000[diff] [blame]5117<p>If the <tt>inbounds</tt> keyword is present, the result value of the
Dan Gohman27ef9972010-04-23 15:23:32 +0000[diff] [blame]5118 <tt>getelementptr</tt> is a <a href="#trapvalues">trap value</a> if the
5119 base pointer is not an <i>in bounds</i> address of an allocated object,
5120 or if any of the addresses that would be formed by successive addition of
5121 the offsets implied by the indices to the base address with infinitely
Eli Friedman266246c2011-08-12 23:37:55 +0000[diff] [blame]5122 precise signed arithmetic are not an <i>in bounds</i> address of that
5123 allocated object. The <i>in bounds</i> addresses for an allocated object
5124 are all the addresses that point into the object, plus the address one
5125 byte past the end.</p>
Dan Gohmandd8004d2009-07-27 21:53:46 +0000[diff] [blame]5126
5127<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]5128 the base address with silently-wrapping two's complement arithmetic. If the
5129 offsets have a different width from the pointer, they are sign-extended or
5130 truncated to the width of the pointer. The result value of the
5131 <tt>getelementptr</tt> may be outside the object pointed to by the base
5132 pointer. The result value may not necessarily be used to access memory
5133 though, even if it happens to point into allocated storage. See the
5134 <a href="#pointeraliasing">Pointer Aliasing Rules</a> section for more
5135 information.</p>
Dan Gohmandd8004d2009-07-27 21:53:46 +0000[diff] [blame]5136
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5137<p>The getelementptr instruction is often confusing. For some more insight into
5138 how it works, see <a href="GetElementPtr.html">the getelementptr FAQ</a>.</p>
Chris Lattner884a9702006-08-15 00:45:58 +0000[diff] [blame]5139
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]5140<h5>Example:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5141<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5142 <i>; yields [12 x i8]*:aptr</i>
Matthijs Kooijmane49d0bc2008-10-13 13:44:15 +0000[diff] [blame]5143 %aptr = getelementptr {i32, [12 x i8]}* %saptr, i64 0, i32 1
5144 <i>; yields i8*:vptr</i>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]5145 %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]5146 <i>; yields i8*:eptr</i>
5147 %eptr = getelementptr [12 x i8]* %aptr, i64 0, i32 1
Sanjiv Gupta9f805c22009-04-25 07:27:44 +0000[diff] [blame]5148 <i>; yields i32*:iptr</i>
Sanjiv Gupta16ffa802009-04-24 16:38:13 +0000[diff] [blame]5149 %iptr = getelementptr [10 x i32]* @arr, i16 0, i16 0
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5150</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5151
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5152</div>
Reid Spencer47ce1792006-11-09 21:15:49 +0000[diff] [blame]5153
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5154</div>
5155
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]5156<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5157<h3>
5158 <a name="convertops">Conversion Operations</a>
5159</h3>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5160
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5161<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5162
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5163<p>The instructions in this category are the conversion instructions (casting)
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5164 which all take a single operand and a type. They perform various bit
5165 conversions on the operand.</p>
5166
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]5167<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5168<h4>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5169 <a name="i_trunc">'<tt>trunc .. to</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5170</h4>
5171
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5172<div>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5173
5174<h5>Syntax:</h5>
5175<pre>
5176 &lt;result&gt; = trunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
5177</pre>
5178
5179<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5180<p>The '<tt>trunc</tt>' instruction truncates its operand to the
5181 type <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5182
5183<h5>Arguments:</h5>
Nadav Rotem8c20ec52011-02-24 21:01:34 +0000[diff] [blame]5184<p>The '<tt>trunc</tt>' instruction takes a value to trunc, and a type to trunc it to.
5185 Both types must be of <a href="#t_integer">integer</a> types, or vectors
5186 of the same number of integers.
5187 The bit size of the <tt>value</tt> must be larger than
5188 the bit size of the destination type, <tt>ty2</tt>.
5189 Equal sized types are not allowed.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5190
5191<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5192<p>The '<tt>trunc</tt>' instruction truncates the high order bits
5193 in <tt>value</tt> and converts the remaining bits to <tt>ty2</tt>. Since the
5194 source size must be larger than the destination size, <tt>trunc</tt> cannot
5195 be a <i>no-op cast</i>. It will always truncate bits.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5196
5197<h5>Example:</h5>
5198<pre>
Nadav Rotem8c20ec52011-02-24 21:01:34 +0000[diff] [blame]5199 %X = trunc i32 257 to i8 <i>; yields i8:1</i>
5200 %Y = trunc i32 123 to i1 <i>; yields i1:true</i>
5201 %Z = trunc i32 122 to i1 <i>; yields i1:false</i>
5202 %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]5203</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5204
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5205</div>
5206
5207<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5208<h4>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5209 <a name="i_zext">'<tt>zext .. to</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5210</h4>
5211
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5212<div>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5213
5214<h5>Syntax:</h5>
5215<pre>
5216 &lt;result&gt; = zext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
5217</pre>
5218
5219<h5>Overview:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5220<p>The '<tt>zext</tt>' instruction zero extends its operand to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5221 <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5222
5223
5224<h5>Arguments:</h5>
Nadav Rotemed9b9342011-02-20 12:37:50 +0000[diff] [blame]5225<p>The '<tt>zext</tt>' instruction takes a value to cast, and a type to cast it to.
5226 Both types must be of <a href="#t_integer">integer</a> types, or vectors
5227 of the same number of integers.
5228 The bit size of the <tt>value</tt> must be smaller than
5229 the bit size of the destination type,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5230 <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5231
5232<h5>Semantics:</h5>
5233<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]5234 bits until it reaches the size of the destination type, <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5235
Reid Spencerb5929522007-01-12 15:46:11 +0000[diff] [blame]5236<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]5237
5238<h5>Example:</h5>
5239<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5240 %X = zext i32 257 to i64 <i>; yields i64:257</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]5241 %Y = zext i1 true to i32 <i>; yields i32:1</i>
Nadav Rotemed9b9342011-02-20 12:37:50 +0000[diff] [blame]5242 %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]5243</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5244
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5245</div>
5246
5247<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5248<h4>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5249 <a name="i_sext">'<tt>sext .. to</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5250</h4>
5251
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5252<div>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5253
5254<h5>Syntax:</h5>
5255<pre>
5256 &lt;result&gt; = sext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
5257</pre>
5258
5259<h5>Overview:</h5>
5260<p>The '<tt>sext</tt>' sign extends <tt>value</tt> to the type <tt>ty2</tt>.</p>
5261
5262<h5>Arguments:</h5>
Nadav Rotem8c20ec52011-02-24 21:01:34 +0000[diff] [blame]5263<p>The '<tt>sext</tt>' instruction takes a value to cast, and a type to cast it to.
5264 Both types must be of <a href="#t_integer">integer</a> types, or vectors
5265 of the same number of integers.
5266 The bit size of the <tt>value</tt> must be smaller than
5267 the bit size of the destination type,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5268 <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5269
5270<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5271<p>The '<tt>sext</tt>' instruction performs a sign extension by copying the sign
5272 bit (highest order bit) of the <tt>value</tt> until it reaches the bit size
5273 of the type <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5274
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]5275<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]5276
5277<h5>Example:</h5>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5278<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5279 %X = sext i8 -1 to i16 <i>; yields i16 :65535</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]5280 %Y = sext i1 true to i32 <i>; yields i32:-1</i>
Nadav Rotem8c20ec52011-02-24 21:01:34 +0000[diff] [blame]5281 %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]5282</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5283
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5284</div>
5285
5286<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5287<h4>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]5288 <a name="i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5289</h4>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]5290
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5291<div>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]5292
5293<h5>Syntax:</h5>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]5294<pre>
5295 &lt;result&gt; = fptrunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
5296</pre>
5297
5298<h5>Overview:</h5>
5299<p>The '<tt>fptrunc</tt>' instruction truncates <tt>value</tt> to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5300 <tt>ty2</tt>.</p>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]5301
5302<h5>Arguments:</h5>
5303<p>The '<tt>fptrunc</tt>' instruction takes a <a href="#t_floating">floating
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5304 point</a> value to cast and a <a href="#t_floating">floating point</a> type
5305 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]5306 <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]5307 <i>no-op cast</i>.</p>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]5308
5309<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5310<p>The '<tt>fptrunc</tt>' instruction truncates a <tt>value</tt> from a larger
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5311 <a href="#t_floating">floating point</a> type to a smaller
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5312 <a href="#t_floating">floating point</a> type. If the value cannot fit
5313 within the destination type, <tt>ty2</tt>, then the results are
5314 undefined.</p>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]5315
5316<h5>Example:</h5>
5317<pre>
5318 %X = fptrunc double 123.0 to float <i>; yields float:123.0</i>
5319 %Y = fptrunc double 1.0E+300 to float <i>; yields undefined</i>
5320</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5321
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]5322</div>
5323
5324<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5325<h4>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5326 <a name="i_fpext">'<tt>fpext .. to</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5327</h4>
5328
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5329<div>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5330
5331<h5>Syntax:</h5>
5332<pre>
5333 &lt;result&gt; = fpext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
5334</pre>
5335
5336<h5>Overview:</h5>
5337<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]5338 floating point value.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5339
5340<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5341<p>The '<tt>fpext</tt>' instruction takes a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5342 <a href="#t_floating">floating point</a> <tt>value</tt> to cast, and
5343 a <a href="#t_floating">floating point</a> type to cast it to. The source
5344 type must be smaller than the destination type.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5345
5346<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]5347<p>The '<tt>fpext</tt>' instruction extends the <tt>value</tt> from a smaller
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5348 <a href="#t_floating">floating point</a> type to a larger
5349 <a href="#t_floating">floating point</a> type. The <tt>fpext</tt> cannot be
5350 used to make a <i>no-op cast</i> because it always changes bits. Use
5351 <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]5352
5353<h5>Example:</h5>
5354<pre>
Nick Lewycky5bb3ece2011-03-31 18:20:19 +0000[diff] [blame]5355 %X = fpext float 3.125 to double <i>; yields double:3.125000e+00</i>
5356 %Y = fpext double %X to fp128 <i>; yields fp128:0xL00000000000000004000900000000000</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5357</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5358
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5359</div>
5360
5361<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5362<h4>
Reid Spencer24d6da52007-01-21 00:29:26 +0000[diff] [blame]5363 <a name="i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5364</h4>
5365
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5366<div>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5367
5368<h5>Syntax:</h5>
5369<pre>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]5370 &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]5371</pre>
5372
5373<h5>Overview:</h5>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]5374<p>The '<tt>fptoui</tt>' converts a floating point <tt>value</tt> to its
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5375 unsigned integer equivalent of type <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5376
5377<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5378<p>The '<tt>fptoui</tt>' instruction takes a value to cast, which must be a
5379 scalar or vector <a href="#t_floating">floating point</a> value, and a type
5380 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
5381 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
5382 vector integer type with the same number of elements as <tt>ty</tt></p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5383
5384<h5>Semantics:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5385<p>The '<tt>fptoui</tt>' instruction converts its
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5386 <a href="#t_floating">floating point</a> operand into the nearest (rounding
5387 towards zero) unsigned integer value. If the value cannot fit
5388 in <tt>ty2</tt>, the results are undefined.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5389
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5390<h5>Example:</h5>
5391<pre>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]5392 %X = fptoui double 123.0 to i32 <i>; yields i32:123</i>
Chris Lattner88519042007-09-22 03:17:52 +0000[diff] [blame]5393 %Y = fptoui float 1.0E+300 to i1 <i>; yields undefined:1</i>
Gabor Greif6a292012009-10-28 09:21:30 +0000[diff] [blame]5394 %Z = fptoui float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5395</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5396
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5397</div>
5398
5399<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5400<h4>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]5401 <a name="i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5402</h4>
5403
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5404<div>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5405
5406<h5>Syntax:</h5>
5407<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]5408 &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]5409</pre>
5410
5411<h5>Overview:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5412<p>The '<tt>fptosi</tt>' instruction converts
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5413 <a href="#t_floating">floating point</a> <tt>value</tt> to
5414 type <tt>ty2</tt>.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5415
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]5416<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5417<p>The '<tt>fptosi</tt>' instruction takes a value to cast, which must be a
5418 scalar or vector <a href="#t_floating">floating point</a> value, and a type
5419 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
5420 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
5421 vector integer type with the same number of elements as <tt>ty</tt></p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5422
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]5423<h5>Semantics:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5424<p>The '<tt>fptosi</tt>' instruction converts its
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5425 <a href="#t_floating">floating point</a> operand into the nearest (rounding
5426 towards zero) signed integer value. If the value cannot fit in <tt>ty2</tt>,
5427 the results are undefined.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5428
Chris Lattner33ba0d92001-07-09 00:26:23 +0000[diff] [blame]5429<h5>Example:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5430<pre>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]5431 %X = fptosi double -123.0 to i32 <i>; yields i32:-123</i>
Chris Lattner88519042007-09-22 03:17:52 +0000[diff] [blame]5432 %Y = fptosi float 1.0E-247 to i1 <i>; yields undefined:1</i>
Gabor Greif6a292012009-10-28 09:21:30 +0000[diff] [blame]5433 %Z = fptosi float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5434</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5435
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5436</div>
5437
5438<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5439<h4>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]5440 <a name="i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5441</h4>
5442
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5443<div>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5444
5445<h5>Syntax:</h5>
5446<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]5447 &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]5448</pre>
5449
5450<h5>Overview:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]5451<p>The '<tt>uitofp</tt>' instruction regards <tt>value</tt> as an unsigned
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5452 integer and converts that value to the <tt>ty2</tt> type.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5453
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5454<h5>Arguments:</h5>
Nate Begemanb348d182007-11-17 03:58:34 +0000[diff] [blame]5455<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]5456 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
5457 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
5458 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
5459 floating point type with the same number of elements as <tt>ty</tt></p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5460
5461<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]5462<p>The '<tt>uitofp</tt>' instruction interprets its operand as an unsigned
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5463 integer quantity and converts it to the corresponding floating point
5464 value. If the value cannot fit in the floating point value, the results are
5465 undefined.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5466
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5467<h5>Example:</h5>
5468<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5469 %X = uitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]5470 %Y = uitofp i8 -1 to double <i>; yields double:255.0</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5471</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5472
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5473</div>
5474
5475<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5476<h4>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]5477 <a name="i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5478</h4>
5479
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5480<div>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5481
5482<h5>Syntax:</h5>
5483<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]5484 &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]5485</pre>
5486
5487<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5488<p>The '<tt>sitofp</tt>' instruction regards <tt>value</tt> as a signed integer
5489 and converts that value to the <tt>ty2</tt> type.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5490
5491<h5>Arguments:</h5>
Nate Begemanb348d182007-11-17 03:58:34 +0000[diff] [blame]5492<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]5493 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
5494 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
5495 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
5496 floating point type with the same number of elements as <tt>ty</tt></p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5497
5498<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5499<p>The '<tt>sitofp</tt>' instruction interprets its operand as a signed integer
5500 quantity and converts it to the corresponding floating point value. If the
5501 value cannot fit in the floating point value, the results are undefined.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5502
5503<h5>Example:</h5>
5504<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5505 %X = sitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]5506 %Y = sitofp i8 -1 to double <i>; yields double:-1.0</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5507</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5508
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5509</div>
5510
5511<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5512<h4>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]5513 <a name="i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5514</h4>
5515
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5516<div>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]5517
5518<h5>Syntax:</h5>
5519<pre>
5520 &lt;result&gt; = ptrtoint &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
5521</pre>
5522
5523<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5524<p>The '<tt>ptrtoint</tt>' instruction converts the pointer <tt>value</tt> to
5525 the integer type <tt>ty2</tt>.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]5526
5527<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5528<p>The '<tt>ptrtoint</tt>' instruction takes a <tt>value</tt> to cast, which
5529 must be a <a href="#t_pointer">pointer</a> value, and a type to cast it to
5530 <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]5531
5532<h5>Semantics:</h5>
5533<p>The '<tt>ptrtoint</tt>' instruction converts <tt>value</tt> to integer type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5534 <tt>ty2</tt> by interpreting the pointer value as an integer and either
5535 truncating or zero extending that value to the size of the integer type. If
5536 <tt>value</tt> is smaller than <tt>ty2</tt> then a zero extension is done. If
5537 <tt>value</tt> is larger than <tt>ty2</tt> then a truncation is done. If they
5538 are the same size, then nothing is done (<i>no-op cast</i>) other than a type
5539 change.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]5540
5541<h5>Example:</h5>
5542<pre>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5543 %X = ptrtoint i32* %X to i8 <i>; yields truncation on 32-bit architecture</i>
5544 %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]5545</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5546
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]5547</div>
5548
5549<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5550<h4>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]5551 <a name="i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5552</h4>
5553
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5554<div>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]5555
5556<h5>Syntax:</h5>
5557<pre>
5558 &lt;result&gt; = inttoptr &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
5559</pre>
5560
5561<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5562<p>The '<tt>inttoptr</tt>' instruction converts an integer <tt>value</tt> to a
5563 pointer type, <tt>ty2</tt>.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]5564
5565<h5>Arguments:</h5>
Duncan Sands8036ca42007-03-30 12:22:09 +0000[diff] [blame]5566<p>The '<tt>inttoptr</tt>' instruction takes an <a href="#t_integer">integer</a>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5567 value to cast, and a type to cast it to, which must be a
5568 <a href="#t_pointer">pointer</a> type.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]5569
5570<h5>Semantics:</h5>
5571<p>The '<tt>inttoptr</tt>' instruction converts <tt>value</tt> to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5572 <tt>ty2</tt> by applying either a zero extension or a truncation depending on
5573 the size of the integer <tt>value</tt>. If <tt>value</tt> is larger than the
5574 size of a pointer then a truncation is done. If <tt>value</tt> is smaller
5575 than the size of a pointer then a zero extension is done. If they are the
5576 same size, nothing is done (<i>no-op cast</i>).</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]5577
5578<h5>Example:</h5>
5579<pre>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5580 %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]5581 %Y = inttoptr i32 255 to i32* <i>; yields no-op on 32-bit architecture</i>
5582 %Z = inttoptr i64 0 to i32* <i>; yields truncation on 32-bit architecture</i>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]5583</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5584
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]5585</div>
5586
5587<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5588<h4>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]5589 <a name="i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5590</h4>
5591
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5592<div>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5593
5594<h5>Syntax:</h5>
5595<pre>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]5596 &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]5597</pre>
5598
5599<h5>Overview:</h5>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]5600<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5601 <tt>ty2</tt> without changing any bits.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5602
5603<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5604<p>The '<tt>bitcast</tt>' instruction takes a value to cast, which must be a
5605 non-aggregate first class value, and a type to cast it to, which must also be
5606 a non-aggregate <a href="#t_firstclass">first class</a> type. The bit sizes
5607 of <tt>value</tt> and the destination type, <tt>ty2</tt>, must be
5608 identical. If the source type is a pointer, the destination type must also be
5609 a pointer. This instruction supports bitwise conversion of vectors to
5610 integers and to vectors of other types (as long as they have the same
5611 size).</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5612
5613<h5>Semantics:</h5>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]5614<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5615 <tt>ty2</tt>. It is always a <i>no-op cast</i> because no bits change with
5616 this conversion. The conversion is done as if the <tt>value</tt> had been
5617 stored to memory and read back as type <tt>ty2</tt>. Pointer types may only
5618 be converted to other pointer types with this instruction. To convert
5619 pointers to other types, use the <a href="#i_inttoptr">inttoptr</a> or
5620 <a href="#i_ptrtoint">ptrtoint</a> instructions first.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5621
5622<h5>Example:</h5>
5623<pre>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5624 %X = bitcast i8 255 to i8 <i>; yields i8 :-1</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5625 %Y = bitcast i32* %x to sint* <i>; yields sint*:%x</i>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5626 %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]5627</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5628
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5629</div>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5630
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5631</div>
5632
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5633<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5634<h3>
5635 <a name="otherops">Other Operations</a>
5636</h3>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5637
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5638<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5639
5640<p>The instructions in this category are the "miscellaneous" instructions, which
5641 defy better classification.</p>
5642
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5643<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5644<h4>
5645 <a name="i_icmp">'<tt>icmp</tt>' Instruction</a>
5646</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5647
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5648<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5649
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5650<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5651<pre>
5652 &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]5653</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5654
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5655<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5656<p>The '<tt>icmp</tt>' instruction returns a boolean value or a vector of
5657 boolean values based on comparison of its two integer, integer vector, or
5658 pointer operands.</p>
5659
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5660<h5>Arguments:</h5>
5661<p>The '<tt>icmp</tt>' instruction takes three operands. The first operand is
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5662 the condition code indicating the kind of comparison to perform. It is not a
5663 value, just a keyword. The possible condition code are:</p>
5664
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5665<ol>
5666 <li><tt>eq</tt>: equal</li>
5667 <li><tt>ne</tt>: not equal </li>
5668 <li><tt>ugt</tt>: unsigned greater than</li>
5669 <li><tt>uge</tt>: unsigned greater or equal</li>
5670 <li><tt>ult</tt>: unsigned less than</li>
5671 <li><tt>ule</tt>: unsigned less or equal</li>
5672 <li><tt>sgt</tt>: signed greater than</li>
5673 <li><tt>sge</tt>: signed greater or equal</li>
5674 <li><tt>slt</tt>: signed less than</li>
5675 <li><tt>sle</tt>: signed less or equal</li>
5676</ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5677
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]5678<p>The remaining two arguments must be <a href="#t_integer">integer</a> or
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5679 <a href="#t_pointer">pointer</a> or integer <a href="#t_vector">vector</a>
5680 typed. They must also be identical types.</p>
5681
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5682<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5683<p>The '<tt>icmp</tt>' compares <tt>op1</tt> and <tt>op2</tt> according to the
5684 condition code given as <tt>cond</tt>. The comparison performed always yields
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]5685 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]5686 result, as follows:</p>
5687
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5688<ol>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5689 <li><tt>eq</tt>: yields <tt>true</tt> if the operands are equal,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5690 <tt>false</tt> otherwise. No sign interpretation is necessary or
5691 performed.</li>
5692
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5693 <li><tt>ne</tt>: yields <tt>true</tt> if the operands are unequal,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5694 <tt>false</tt> otherwise. No sign interpretation is necessary or
5695 performed.</li>
5696
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5697 <li><tt>ugt</tt>: interprets the operands as unsigned values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5698 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
5699
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5700 <li><tt>uge</tt>: interprets the operands as unsigned values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5701 <tt>true</tt> if <tt>op1</tt> is greater than or equal
5702 to <tt>op2</tt>.</li>
5703
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5704 <li><tt>ult</tt>: interprets the operands as unsigned values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5705 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
5706
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5707 <li><tt>ule</tt>: interprets the operands as unsigned values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5708 <tt>true</tt> if <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
5709
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5710 <li><tt>sgt</tt>: interprets the operands as signed values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5711 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
5712
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5713 <li><tt>sge</tt>: interprets the operands as signed values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5714 <tt>true</tt> if <tt>op1</tt> is greater than or equal
5715 to <tt>op2</tt>.</li>
5716
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5717 <li><tt>slt</tt>: interprets the operands as signed values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5718 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
5719
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5720 <li><tt>sle</tt>: interprets the operands as signed values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5721 <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]5722</ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5723
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5724<p>If the operands are <a href="#t_pointer">pointer</a> typed, the pointer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5725 values are compared as if they were integers.</p>
5726
5727<p>If the operands are integer vectors, then they are compared element by
5728 element. The result is an <tt>i1</tt> vector with the same number of elements
5729 as the values being compared. Otherwise, the result is an <tt>i1</tt>.</p>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5730
5731<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5732<pre>
5733 &lt;result&gt; = icmp eq i32 4, 5 <i>; yields: result=false</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5734 &lt;result&gt; = icmp ne float* %X, %X <i>; yields: result=false</i>
5735 &lt;result&gt; = icmp ult i16 4, 5 <i>; yields: result=true</i>
5736 &lt;result&gt; = icmp sgt i16 4, 5 <i>; yields: result=false</i>
5737 &lt;result&gt; = icmp ule i16 -4, 5 <i>; yields: result=false</i>
5738 &lt;result&gt; = icmp sge i16 4, 5 <i>; yields: result=false</i>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5739</pre>
Dan Gohmanc766f722009-01-22 01:39:38 +0000[diff] [blame]5740
5741<p>Note that the code generator does not yet support vector types with
5742 the <tt>icmp</tt> instruction.</p>
5743
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5744</div>
5745
5746<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5747<h4>
5748 <a name="i_fcmp">'<tt>fcmp</tt>' Instruction</a>
5749</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5750
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5751<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5752
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5753<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5754<pre>
5755 &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]5756</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5757
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5758<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5759<p>The '<tt>fcmp</tt>' instruction returns a boolean value or vector of boolean
5760 values based on comparison of its operands.</p>
5761
5762<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]5763(<a href="#t_integer"><tt>i1</tt></a>).</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5764
5765<p>If the operands are floating point vectors, then the result type is a vector
5766 of boolean with the same number of elements as the operands being
5767 compared.</p>
5768
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5769<h5>Arguments:</h5>
5770<p>The '<tt>fcmp</tt>' instruction takes three operands. The first operand is
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5771 the condition code indicating the kind of comparison to perform. It is not a
5772 value, just a keyword. The possible condition code are:</p>
5773
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5774<ol>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]5775 <li><tt>false</tt>: no comparison, always returns false</li>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5776 <li><tt>oeq</tt>: ordered and equal</li>
5777 <li><tt>ogt</tt>: ordered and greater than </li>
5778 <li><tt>oge</tt>: ordered and greater than or equal</li>
5779 <li><tt>olt</tt>: ordered and less than </li>
5780 <li><tt>ole</tt>: ordered and less than or equal</li>
5781 <li><tt>one</tt>: ordered and not equal</li>
5782 <li><tt>ord</tt>: ordered (no nans)</li>
5783 <li><tt>ueq</tt>: unordered or equal</li>
5784 <li><tt>ugt</tt>: unordered or greater than </li>
5785 <li><tt>uge</tt>: unordered or greater than or equal</li>
5786 <li><tt>ult</tt>: unordered or less than </li>
5787 <li><tt>ule</tt>: unordered or less than or equal</li>
5788 <li><tt>une</tt>: unordered or not equal</li>
5789 <li><tt>uno</tt>: unordered (either nans)</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]5790 <li><tt>true</tt>: no comparison, always returns true</li>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5791</ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5792
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5793<p><i>Ordered</i> means that neither operand is a QNAN while
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5794 <i>unordered</i> means that either operand may be a QNAN.</p>
5795
5796<p>Each of <tt>val1</tt> and <tt>val2</tt> arguments must be either
5797 a <a href="#t_floating">floating point</a> type or
5798 a <a href="#t_vector">vector</a> of floating point type. They must have
5799 identical types.</p>
5800
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5801<h5>Semantics:</h5>
Gabor Greiffb224a22008-08-07 21:46:00 +0000[diff] [blame]5802<p>The '<tt>fcmp</tt>' instruction compares <tt>op1</tt> and <tt>op2</tt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5803 according to the condition code given as <tt>cond</tt>. If the operands are
5804 vectors, then the vectors are compared element by element. Each comparison
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]5805 performed always yields an <a href="#t_integer">i1</a> result, as
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5806 follows:</p>
5807
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5808<ol>
5809 <li><tt>false</tt>: always yields <tt>false</tt>, regardless of operands.</li>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5810
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5811 <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]5812 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
5813
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]5814 <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]5815 <tt>op1</tt> is greater than <tt>op2</tt>.</li>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5816
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5817 <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]5818 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
5819
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5820 <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]5821 <tt>op1</tt> is less than <tt>op2</tt>.</li>
5822
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5823 <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]5824 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
5825
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5826 <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]5827 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
5828
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]5829 <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]5830
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5831 <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]5832 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
5833
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5834 <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]5835 <tt>op1</tt> is greater than <tt>op2</tt>.</li>
5836
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5837 <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]5838 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
5839
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5840 <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]5841 <tt>op1</tt> is less than <tt>op2</tt>.</li>
5842
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5843 <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]5844 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
5845
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5846 <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]5847 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
5848
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]5849 <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]5850
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5851 <li><tt>true</tt>: always yields <tt>true</tt>, regardless of operands.</li>
5852</ol>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5853
5854<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5855<pre>
5856 &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]5857 &lt;result&gt; = fcmp one float 4.0, 5.0 <i>; yields: result=true</i>
5858 &lt;result&gt; = fcmp olt float 4.0, 5.0 <i>; yields: result=true</i>
5859 &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]5860</pre>
Dan Gohmanc766f722009-01-22 01:39:38 +0000[diff] [blame]5861
5862<p>Note that the code generator does not yet support vector types with
5863 the <tt>fcmp</tt> instruction.</p>
5864
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5865</div>
5866
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5867<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5868<h4>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5869 <a name="i_phi">'<tt>phi</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5870</h4>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5871
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5872<div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5873
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5874<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5875<pre>
5876 &lt;result&gt; = phi &lt;ty&gt; [ &lt;val0&gt;, &lt;label0&gt;], ...
5877</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5878
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5879<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5880<p>The '<tt>phi</tt>' instruction is used to implement the &#966; node in the
5881 SSA graph representing the function.</p>
5882
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5883<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5884<p>The type of the incoming values is specified with the first type field. After
5885 this, the '<tt>phi</tt>' instruction takes a list of pairs as arguments, with
5886 one pair for each predecessor basic block of the current block. Only values
5887 of <a href="#t_firstclass">first class</a> type may be used as the value
5888 arguments to the PHI node. Only labels may be used as the label
5889 arguments.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5890
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5891<p>There must be no non-phi instructions between the start of a basic block and
5892 the PHI instructions: i.e. PHI instructions must be first in a basic
5893 block.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5894
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5895<p>For the purposes of the SSA form, the use of each incoming value is deemed to
5896 occur on the edge from the corresponding predecessor block to the current
5897 block (but after any definition of an '<tt>invoke</tt>' instruction's return
5898 value on the same edge).</p>
Jay Foadd2449092009-06-03 10:20:10 +0000[diff] [blame]5899
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5900<h5>Semantics:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5901<p>At runtime, the '<tt>phi</tt>' instruction logically takes on the value
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5902 specified by the pair corresponding to the predecessor basic block that
5903 executed just prior to the current block.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5904
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5905<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5906<pre>
5907Loop: ; Infinite loop that counts from 0 on up...
5908 %indvar = phi i32 [ 0, %LoopHeader ], [ %nextindvar, %Loop ]
5909 %nextindvar = add i32 %indvar, 1
5910 br label %Loop
5911</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5912
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5913</div>
5914
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5915<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5916<h4>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5917 <a name="i_select">'<tt>select</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5918</h4>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5919
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5920<div>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5921
5922<h5>Syntax:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5923<pre>
Dan Gohmanf72fb672008-09-09 01:02:47 +0000[diff] [blame]5924 &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>
5925
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]5926 <i>selty</i> is either i1 or {&lt;N x i1&gt;}
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5927</pre>
5928
5929<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5930<p>The '<tt>select</tt>' instruction is used to choose one value based on a
5931 condition, without branching.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5932
5933
5934<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5935<p>The '<tt>select</tt>' instruction requires an 'i1' value or a vector of 'i1'
5936 values indicating the condition, and two values of the
5937 same <a href="#t_firstclass">first class</a> type. If the val1/val2 are
5938 vectors and the condition is a scalar, then entire vectors are selected, not
5939 individual elements.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5940
5941<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5942<p>If the condition is an i1 and it evaluates to 1, the instruction returns the
5943 first value argument; otherwise, it returns the second value argument.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5944
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5945<p>If the condition is a vector of i1, then the value arguments must be vectors
5946 of the same size, and the selection is done element by element.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5947
5948<h5>Example:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5949<pre>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]5950 %X = select i1 true, i8 17, i8 42 <i>; yields i8:17</i>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5951</pre>
Dan Gohmanc766f722009-01-22 01:39:38 +0000[diff] [blame]5952
5953<p>Note that the code generator does not yet support conditions
5954 with vector type.</p>
5955
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5956</div>
5957
Robert Bocchino05ccd702006-01-15 20:48:27 +0000[diff] [blame]5958<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5959<h4>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5960 <a name="i_call">'<tt>call</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5961</h4>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5962
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5963<div>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5964
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]5965<h5>Syntax:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5966<pre>
Devang Patel307e8ab2008-10-07 17:48:33 +0000[diff] [blame]5967 &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]5968</pre>
5969
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]5970<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5971<p>The '<tt>call</tt>' instruction represents a simple function call.</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5972
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]5973<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5974<p>This instruction requires several arguments:</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5975
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]5976<ol>
Jeffrey Yasskin95fa80a2010-01-09 19:44:16 +0000[diff] [blame]5977 <li>The optional "tail" marker indicates that the callee function does not
5978 access any allocas or varargs in the caller. Note that calls may be
5979 marked "tail" even if they do not occur before
5980 a <a href="#i_ret"><tt>ret</tt></a> instruction. If the "tail" marker is
5981 present, the function call is eligible for tail call optimization,
5982 but <a href="CodeGenerator.html#tailcallopt">might not in fact be
Evan Chengdc444e92010-03-08 21:05:02 +0000[diff] [blame]5983 optimized into a jump</a>. The code generator may optimize calls marked
5984 "tail" with either 1) automatic <a href="CodeGenerator.html#sibcallopt">
5985 sibling call optimization</a> when the caller and callee have
5986 matching signatures, or 2) forced tail call optimization when the
5987 following extra requirements are met:
Jeffrey Yasskin95fa80a2010-01-09 19:44:16 +0000[diff] [blame]5988 <ul>
5989 <li>Caller and callee both have the calling
5990 convention <tt>fastcc</tt>.</li>
5991 <li>The call is in tail position (ret immediately follows call and ret
5992 uses value of call or is void).</li>
5993 <li>Option <tt>-tailcallopt</tt> is enabled,
Dan Gohmanfbbee8d2010-03-02 01:08:11 +0000[diff] [blame]5994 or <code>llvm::GuaranteedTailCallOpt</code> is <code>true</code>.</li>
Jeffrey Yasskin95fa80a2010-01-09 19:44:16 +0000[diff] [blame]5995 <li><a href="CodeGenerator.html#tailcallopt">Platform specific
5996 constraints are met.</a></li>
5997 </ul>
5998 </li>
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]5999
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6000 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
6001 convention</a> the call should use. If none is specified, the call
Jeffrey Yasskin95fa80a2010-01-09 19:44:16 +0000[diff] [blame]6002 defaults to using C calling conventions. The calling convention of the
6003 call must match the calling convention of the target function, or else the
6004 behavior is undefined.</li>
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]6005
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6006 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
6007 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
6008 '<tt>inreg</tt>' attributes are valid here.</li>
6009
6010 <li>'<tt>ty</tt>': the type of the call instruction itself which is also the
6011 type of the return value. Functions that return no value are marked
6012 <tt><a href="#t_void">void</a></tt>.</li>
6013
6014 <li>'<tt>fnty</tt>': shall be the signature of the pointer to function value
6015 being invoked. The argument types must match the types implied by this
6016 signature. This type can be omitted if the function is not varargs and if
6017 the function type does not return a pointer to a function.</li>
6018
6019 <li>'<tt>fnptrval</tt>': An LLVM value containing a pointer to a function to
6020 be invoked. In most cases, this is a direct function invocation, but
6021 indirect <tt>call</tt>s are just as possible, calling an arbitrary pointer
6022 to function value.</li>
6023
6024 <li>'<tt>function args</tt>': argument list whose types match the function
Chris Lattner0724fbd2010-03-02 06:36:51 +0000[diff] [blame]6025 signature argument types and parameter attributes. All arguments must be
6026 of <a href="#t_firstclass">first class</a> type. If the function
6027 signature indicates the function accepts a variable number of arguments,
6028 the extra arguments can be specified.</li>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6029
6030 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
6031 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
6032 '<tt>readnone</tt>' attributes are valid here.</li>
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]6033</ol>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]6034
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]6035<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6036<p>The '<tt>call</tt>' instruction is used to cause control flow to transfer to
6037 a specified function, with its incoming arguments bound to the specified
6038 values. Upon a '<tt><a href="#i_ret">ret</a></tt>' instruction in the called
6039 function, control flow continues with the instruction after the function
6040 call, and the return value of the function is bound to the result
6041 argument.</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]6042
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]6043<h5>Example:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]6044<pre>
Nick Lewyckydb7e3c92007-09-08 13:57:50 +0000[diff] [blame]6045 %retval = call i32 @test(i32 %argc)
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]6046 call i32 (i8*, ...)* @printf(i8* %msg, i32 12, i8 42) <i>; yields i32</i>
Chris Lattner772fccf2008-03-21 17:24:17 +0000[diff] [blame]6047 %X = tail call i32 @foo() <i>; yields i32</i>
6048 %Y = tail call <a href="#callingconv">fastcc</a> i32 @foo() <i>; yields i32</i>
6049 call void %foo(i8 97 signext)
Devang Patelc3fc6df2008-03-10 20:49:15 +0000[diff] [blame]6050
6051 %struct.A = type { i32, i8 }
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]6052 %r = call %struct.A @foo() <i>; yields { 32, i8 }</i>
Dan Gohmanb1e6b962008-10-04 19:00:07 +0000[diff] [blame]6053 %gr = extractvalue %struct.A %r, 0 <i>; yields i32</i>
6054 %gr1 = extractvalue %struct.A %r, 1 <i>; yields i8</i>
Chris Lattner85a350f2008-10-08 06:26:11 +0000[diff] [blame]6055 %Z = call void @foo() noreturn <i>; indicates that %foo never returns normally</i>
Matthijs Kooijmancb73d192008-10-07 10:03:45 +0000[diff] [blame]6056 %ZZ = call zeroext i32 @bar() <i>; Return value is %zero extended</i>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]6057</pre>
6058
Dale Johannesen07de8d12009-09-24 18:38:21 +0000[diff] [blame]6059<p>llvm treats calls to some functions with names and arguments that match the
Dale Johannesen9f8380b2009-09-25 17:04:42 +0000[diff] [blame]6060standard C99 library as being the C99 library functions, and may perform
6061optimizations or generate code for them under that assumption. This is
6062something we'd like to change in the future to provide better support for
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]6063freestanding environments and non-C-based languages.</p>
Dale Johannesen07de8d12009-09-24 18:38:21 +0000[diff] [blame]6064
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]6065</div>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]6066
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6067<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6068<h4>
Chris Lattnerfb6977d2006-01-13 23:26:01 +0000[diff] [blame]6069 <a name="i_va_arg">'<tt>va_arg</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6070</h4>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]6071
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6072<div>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]6073
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]6074<h5>Syntax:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]6075<pre>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]6076 &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]6077</pre>
6078
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]6079<h5>Overview:</h5>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]6080<p>The '<tt>va_arg</tt>' instruction is used to access arguments passed through
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6081 the "variable argument" area of a function call. It is used to implement the
6082 <tt>va_arg</tt> macro in C.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]6083
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]6084<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6085<p>This instruction takes a <tt>va_list*</tt> value and the type of the
6086 argument. It returns a value of the specified argument type and increments
6087 the <tt>va_list</tt> to point to the next argument. The actual type
6088 of <tt>va_list</tt> is target specific.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]6089
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]6090<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6091<p>The '<tt>va_arg</tt>' instruction loads an argument of the specified type
6092 from the specified <tt>va_list</tt> and causes the <tt>va_list</tt> to point
6093 to the next argument. For more information, see the variable argument
6094 handling <a href="#int_varargs">Intrinsic Functions</a>.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]6095
6096<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]6097 take a variable number of arguments, for example, the <tt>vfprintf</tt>
6098 function.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]6099
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6100<p><tt>va_arg</tt> is an LLVM instruction instead of
6101 an <a href="#intrinsics">intrinsic function</a> because it takes a type as an
6102 argument.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]6103
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]6104<h5>Example:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]6105<p>See the <a href="#int_varargs">variable argument processing</a> section.</p>
6106
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6107<p>Note that the code generator does not yet fully support va_arg on many
6108 targets. Also, it does not currently support va_arg with aggregate types on
6109 any target.</p>
Dan Gohmanf3e60bd2009-01-12 23:12:39 +0000[diff] [blame]6110
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]6111</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6112
Bill Wendlingf78faf82011-08-02 21:52:38 +0000[diff] [blame]6113<!-- _______________________________________________________________________ -->
6114<h4>
6115 <a name="i_landingpad">'<tt>landingpad</tt>' Instruction</a>
6116</h4>
6117
6118<div>
6119
6120<h5>Syntax:</h5>
6121<pre>
Bill Wendlingbf13ee12011-08-08 08:06:05 +0000[diff] [blame]6122 &lt;resultval&gt; = landingpad &lt;somety&gt; personality &lt;type&gt; &lt;pers_fn&gt; &lt;clause&gt;+
6123 &lt;resultval&gt; = landingpad &lt;somety&gt; personality &lt;type&gt; &lt;pers_fn&gt; cleanup &lt;clause&gt;*
6124
Bill Wendlingf78faf82011-08-02 21:52:38 +0000[diff] [blame]6125 &lt;clause&gt; := catch &lt;type&gt; &lt;value&gt;
Bill Wendlinge6e88262011-08-12 20:24:12 +0000[diff] [blame]6126 &lt;clause&gt; := filter &lt;array constant type&gt; &lt;array constant&gt;
Bill Wendlingf78faf82011-08-02 21:52:38 +0000[diff] [blame]6127</pre>
6128
6129<h5>Overview:</h5>
6130<p>The '<tt>landingpad</tt>' instruction is used by
6131 <a href="ExceptionHandling.html#overview">LLVM's exception handling
6132 system</a> to specify that a basic block is a landing pad &mdash; one where
6133 the exception lands, and corresponds to the code found in the
6134 <i><tt>catch</tt></i> portion of a <i><tt>try/catch</tt></i> sequence. It
6135 defines values supplied by the personality function (<tt>pers_fn</tt>) upon
6136 re-entry to the function. The <tt>resultval</tt> has the
6137 type <tt>somety</tt>.</p>
6138
6139<h5>Arguments:</h5>
6140<p>This instruction takes a <tt>pers_fn</tt> value. This is the personality
6141 function associated with the unwinding mechanism. The optional
6142 <tt>cleanup</tt> flag indicates that the landing pad block is a cleanup.</p>
6143
6144<p>A <tt>clause</tt> begins with the clause type &mdash; <tt>catch</tt>
Bill Wendlinge6e88262011-08-12 20:24:12 +0000[diff] [blame]6145 or <tt>filter</tt> &mdash; and contains the global variable representing the
6146 "type" that may be caught or filtered respectively. Unlike the
6147 <tt>catch</tt> clause, the <tt>filter</tt> clause takes an array constant as
6148 its argument. Use "<tt>[0 x i8**] undef</tt>" for a filter which cannot
6149 throw. The '<tt>landingpad</tt>' instruction must contain <em>at least</em>
Bill Wendlingf78faf82011-08-02 21:52:38 +0000[diff] [blame]6150 one <tt>clause</tt> or the <tt>cleanup</tt> flag.</p>
6151
6152<h5>Semantics:</h5>
6153<p>The '<tt>landingpad</tt>' instruction defines the values which are set by the
6154 personality function (<tt>pers_fn</tt>) upon re-entry to the function, and
6155 therefore the "result type" of the <tt>landingpad</tt> instruction. As with
6156 calling conventions, how the personality function results are represented in
6157 LLVM IR is target specific.</p>
6158
Bill Wendlingb7a01352011-08-03 17:17:06 +0000[diff] [blame]6159<p>The clauses are applied in order from top to bottom. If two
6160 <tt>landingpad</tt> instructions are merged together through inlining, the
Bill Wendling2905c322011-08-08 07:58:58 +0000[diff] [blame]6161 clauses from the calling function are appended to the list of clauses.</p>
Bill Wendlingb7a01352011-08-03 17:17:06 +0000[diff] [blame]6162
Bill Wendlingf78faf82011-08-02 21:52:38 +0000[diff] [blame]6163<p>The <tt>landingpad</tt> instruction has several restrictions:</p>
6164
6165<ul>
6166 <li>A landing pad block is a basic block which is the unwind destination of an
6167 '<tt>invoke</tt>' instruction.</li>
6168 <li>A landing pad block must have a '<tt>landingpad</tt>' instruction as its
6169 first non-PHI instruction.</li>
6170 <li>There can be only one '<tt>landingpad</tt>' instruction within the landing
6171 pad block.</li>
6172 <li>A basic block that is not a landing pad block may not include a
6173 '<tt>landingpad</tt>' instruction.</li>
6174 <li>All '<tt>landingpad</tt>' instructions in a function must have the same
6175 personality function.</li>
6176</ul>
6177
6178<h5>Example:</h5>
6179<pre>
6180 ;; A landing pad which can catch an integer.
6181 %res = landingpad { i8*, i32 } personality i32 (...)* @__gxx_personality_v0
6182 catch i8** @_ZTIi
6183 ;; A landing pad that is a cleanup.
6184 %res = landingpad { i8*, i32 } personality i32 (...)* @__gxx_personality_v0
Bill Wendlinge6e88262011-08-12 20:24:12 +0000[diff] [blame]6185 cleanup
Bill Wendlingf78faf82011-08-02 21:52:38 +0000[diff] [blame]6186 ;; A landing pad which can catch an integer and can only throw a double.
6187 %res = landingpad { i8*, i32 } personality i32 (...)* @__gxx_personality_v0
6188 catch i8** @_ZTIi
Bill Wendlinge6e88262011-08-12 20:24:12 +0000[diff] [blame]6189 filter [1 x i8**] [@_ZTId]
Bill Wendlingf78faf82011-08-02 21:52:38 +0000[diff] [blame]6190</pre>
6191
6192</div>
6193
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6194</div>
6195
6196</div>
6197
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6198<!-- *********************************************************************** -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6199<h2><a name="intrinsics">Intrinsic Functions</a></h2>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]6200<!-- *********************************************************************** -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6201
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6202<div>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6203
6204<p>LLVM supports the notion of an "intrinsic function". These functions have
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6205 well known names and semantics and are required to follow certain
6206 restrictions. Overall, these intrinsics represent an extension mechanism for
6207 the LLVM language that does not require changing all of the transformations
6208 in LLVM when adding to the language (or the bitcode reader/writer, the
6209 parser, etc...).</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6210
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]6211<p>Intrinsic function names must all start with an "<tt>llvm.</tt>" prefix. This
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6212 prefix is reserved in LLVM for intrinsic names; thus, function names may not
6213 begin with this prefix. Intrinsic functions must always be external
6214 functions: you cannot define the body of intrinsic functions. Intrinsic
6215 functions may only be used in call or invoke instructions: it is illegal to
6216 take the address of an intrinsic function. Additionally, because intrinsic
6217 functions are part of the LLVM language, it is required if any are added that
6218 they be documented here.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6219
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6220<p>Some intrinsic functions can be overloaded, i.e., the intrinsic represents a
6221 family of functions that perform the same operation but on different data
6222 types. Because LLVM can represent over 8 million different integer types,
6223 overloading is used commonly to allow an intrinsic function to operate on any
6224 integer type. One or more of the argument types or the result type can be
6225 overloaded to accept any integer type. Argument types may also be defined as
6226 exactly matching a previous argument's type or the result type. This allows
6227 an intrinsic function which accepts multiple arguments, but needs all of them
6228 to be of the same type, to only be overloaded with respect to a single
6229 argument or the result.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6230
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6231<p>Overloaded intrinsics will have the names of its overloaded argument types
6232 encoded into its function name, each preceded by a period. Only those types
6233 which are overloaded result in a name suffix. Arguments whose type is matched
6234 against another type do not. For example, the <tt>llvm.ctpop</tt> function
6235 can take an integer of any width and returns an integer of exactly the same
6236 integer width. This leads to a family of functions such as
6237 <tt>i8 @llvm.ctpop.i8(i8 %val)</tt> and <tt>i29 @llvm.ctpop.i29(i29
6238 %val)</tt>. Only one type, the return type, is overloaded, and only one type
6239 suffix is required. Because the argument's type is matched against the return
6240 type, it does not require its own name suffix.</p>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]6241
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]6242<p>To learn how to add an intrinsic function, please see the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6243 <a href="ExtendingLLVM.html">Extending LLVM Guide</a>.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6244
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6245<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6246<h3>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6247 <a name="int_varargs">Variable Argument Handling Intrinsics</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6248</h3>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6249
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6250<div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6251
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6252<p>Variable argument support is defined in LLVM with
6253 the <a href="#i_va_arg"><tt>va_arg</tt></a> instruction and these three
6254 intrinsic functions. These functions are related to the similarly named
6255 macros defined in the <tt>&lt;stdarg.h&gt;</tt> header file.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6256
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6257<p>All of these functions operate on arguments that use a target-specific value
6258 type "<tt>va_list</tt>". The LLVM assembly language reference manual does
6259 not define what this type is, so all transformations should be prepared to
6260 handle these functions regardless of the type used.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6261
Chris Lattner374ab302006-05-15 17:26:46 +0000[diff] [blame]6262<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]6263 instruction and the variable argument handling intrinsic functions are
6264 used.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6265
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]6266<pre class="doc_code">
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]6267define i32 @test(i32 %X, ...) {
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6268 ; Initialize variable argument processing
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]6269 %ap = alloca i8*
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]6270 %ap2 = bitcast i8** %ap to i8*
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]6271 call void @llvm.va_start(i8* %ap2)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6272
6273 ; Read a single integer argument
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]6274 %tmp = va_arg i8** %ap, i32
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6275
6276 ; Demonstrate usage of llvm.va_copy and llvm.va_end
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]6277 %aq = alloca i8*
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]6278 %aq2 = bitcast i8** %aq to i8*
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]6279 call void @llvm.va_copy(i8* %aq2, i8* %ap2)
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]6280 call void @llvm.va_end(i8* %aq2)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6281
6282 ; Stop processing of arguments.
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]6283 call void @llvm.va_end(i8* %ap2)
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]6284 ret i32 %tmp
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6285}
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]6286
6287declare void @llvm.va_start(i8*)
6288declare void @llvm.va_copy(i8*, i8*)
6289declare void @llvm.va_end(i8*)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6290</pre>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6291
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6292<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6293<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6294 <a name="int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6295</h4>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6296
6297
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6298<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6299
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6300<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6301<pre>
6302 declare void %llvm.va_start(i8* &lt;arglist&gt;)
6303</pre>
6304
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6305<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6306<p>The '<tt>llvm.va_start</tt>' intrinsic initializes <tt>*&lt;arglist&gt;</tt>
6307 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]6308
6309<h5>Arguments:</h5>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]6310<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]6311
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6312<h5>Semantics:</h5>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]6313<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]6314 macro available in C. In a target-dependent way, it initializes
6315 the <tt>va_list</tt> element to which the argument points, so that the next
6316 call to <tt>va_arg</tt> will produce the first variable argument passed to
6317 the function. Unlike the C <tt>va_start</tt> macro, this intrinsic does not
6318 need to know the last argument of the function as the compiler can figure
6319 that out.</p>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]6320
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]6321</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6322
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6323<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6324<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6325 <a name="int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6326</h4>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6327
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6328<div>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]6329
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6330<h5>Syntax:</h5>
6331<pre>
6332 declare void @llvm.va_end(i8* &lt;arglist&gt;)
6333</pre>
6334
6335<h5>Overview:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]6336<p>The '<tt>llvm.va_end</tt>' intrinsic destroys <tt>*&lt;arglist&gt;</tt>,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6337 which has been initialized previously
6338 with <tt><a href="#int_va_start">llvm.va_start</a></tt>
6339 or <tt><a href="#i_va_copy">llvm.va_copy</a></tt>.</p>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]6340
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6341<h5>Arguments:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]6342<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]6343
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6344<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]6345<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]6346 macro available in C. In a target-dependent way, it destroys
6347 the <tt>va_list</tt> element to which the argument points. Calls
6348 to <a href="#int_va_start"><tt>llvm.va_start</tt></a>
6349 and <a href="#int_va_copy"> <tt>llvm.va_copy</tt></a> must be matched exactly
6350 with calls to <tt>llvm.va_end</tt>.</p>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]6351
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]6352</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6353
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6354<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6355<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6356 <a name="int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6357</h4>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6358
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6359<div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6360
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6361<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6362<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]6363 declare void @llvm.va_copy(i8* &lt;destarglist&gt;, i8* &lt;srcarglist&gt;)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6364</pre>
6365
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6366<h5>Overview:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]6367<p>The '<tt>llvm.va_copy</tt>' intrinsic copies the current argument position
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6368 from the source argument list to the destination argument list.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6369
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6370<h5>Arguments:</h5>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]6371<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]6372 The second argument is a pointer to a <tt>va_list</tt> element to copy
6373 from.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6374
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6375<h5>Semantics:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]6376<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]6377 macro available in C. In a target-dependent way, it copies the
6378 source <tt>va_list</tt> element into the destination <tt>va_list</tt>
6379 element. This intrinsic is necessary because
6380 the <tt><a href="#int_va_start"> llvm.va_start</a></tt> intrinsic may be
6381 arbitrarily complex and require, for example, memory allocation.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6382
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]6383</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6384
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6385</div>
6386
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6387<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6388<h3>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6389 <a name="int_gc">Accurate Garbage Collection Intrinsics</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6390</h3>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6391
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6392<div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6393
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6394<p>LLVM support for <a href="GarbageCollection.html">Accurate Garbage
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]6395Collection</a> (GC) requires the implementation and generation of these
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6396intrinsics. These intrinsics allow identification of <a href="#int_gcroot">GC
6397roots on the stack</a>, as well as garbage collector implementations that
6398require <a href="#int_gcread">read</a> and <a href="#int_gcwrite">write</a>
6399barriers. Front-ends for type-safe garbage collected languages should generate
6400these intrinsics to make use of the LLVM garbage collectors. For more details,
6401see <a href="GarbageCollection.html">Accurate Garbage Collection with
6402LLVM</a>.</p>
Christopher Lamb303dae92007-12-17 01:00:21 +0000[diff] [blame]6403
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6404<p>The garbage collection intrinsics only operate on objects in the generic
6405 address space (address space zero).</p>
Christopher Lamb303dae92007-12-17 01:00:21 +0000[diff] [blame]6406
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6407<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6408<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6409 <a name="int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6410</h4>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6411
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6412<div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6413
6414<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6415<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]6416 declare void @llvm.gcroot(i8** %ptrloc, i8* %metadata)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6417</pre>
6418
6419<h5>Overview:</h5>
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]6420<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]6421 the code generator, and allows some metadata to be associated with it.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6422
6423<h5>Arguments:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6424<p>The first argument specifies the address of a stack object that contains the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6425 root pointer. The second pointer (which must be either a constant or a
6426 global value address) contains the meta-data to be associated with the
6427 root.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6428
6429<h5>Semantics:</h5>
Chris Lattner05d67092008-04-24 05:59:56 +0000[diff] [blame]6430<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]6431 location. At compile-time, the code generator generates information to allow
6432 the runtime to find the pointer at GC safe points. The '<tt>llvm.gcroot</tt>'
6433 intrinsic may only be used in a function which <a href="#gc">specifies a GC
6434 algorithm</a>.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6435
6436</div>
6437
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6438<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6439<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6440 <a name="int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6441</h4>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6442
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6443<div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6444
6445<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6446<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]6447 declare i8* @llvm.gcread(i8* %ObjPtr, i8** %Ptr)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6448</pre>
6449
6450<h5>Overview:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6451<p>The '<tt>llvm.gcread</tt>' intrinsic identifies reads of references from heap
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6452 locations, allowing garbage collector implementations that require read
6453 barriers.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6454
6455<h5>Arguments:</h5>
Chris Lattner80626e92006-03-14 20:02:51 +0000[diff] [blame]6456<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]6457 allocated from the garbage collector. The first object is a pointer to the
6458 start of the referenced object, if needed by the language runtime (otherwise
6459 null).</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6460
6461<h5>Semantics:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6462<p>The '<tt>llvm.gcread</tt>' intrinsic has the same semantics as a load
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6463 instruction, but may be replaced with substantially more complex code by the
6464 garbage collector runtime, as needed. The '<tt>llvm.gcread</tt>' intrinsic
6465 may only be used in a function which <a href="#gc">specifies a GC
6466 algorithm</a>.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6467
6468</div>
6469
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6470<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6471<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6472 <a name="int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6473</h4>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6474
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6475<div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6476
6477<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6478<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]6479 declare void @llvm.gcwrite(i8* %P1, i8* %Obj, i8** %P2)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6480</pre>
6481
6482<h5>Overview:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6483<p>The '<tt>llvm.gcwrite</tt>' intrinsic identifies writes of references to heap
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6484 locations, allowing garbage collector implementations that require write
6485 barriers (such as generational or reference counting collectors).</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6486
6487<h5>Arguments:</h5>
Chris Lattner80626e92006-03-14 20:02:51 +0000[diff] [blame]6488<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]6489 object to store it to, and the third is the address of the field of Obj to
6490 store to. If the runtime does not require a pointer to the object, Obj may
6491 be null.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6492
6493<h5>Semantics:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6494<p>The '<tt>llvm.gcwrite</tt>' intrinsic has the same semantics as a store
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6495 instruction, but may be replaced with substantially more complex code by the
6496 garbage collector runtime, as needed. The '<tt>llvm.gcwrite</tt>' intrinsic
6497 may only be used in a function which <a href="#gc">specifies a GC
6498 algorithm</a>.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6499
6500</div>
6501
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6502</div>
6503
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6504<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6505<h3>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6506 <a name="int_codegen">Code Generator Intrinsics</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6507</h3>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6508
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6509<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6510
6511<p>These intrinsics are provided by LLVM to expose special features that may
6512 only be implemented with code generator support.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6513
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6514<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6515<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6516 <a name="int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6517</h4>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6518
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6519<div>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6520
6521<h5>Syntax:</h5>
6522<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]6523 declare i8 *@llvm.returnaddress(i32 &lt;level&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6524</pre>
6525
6526<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6527<p>The '<tt>llvm.returnaddress</tt>' intrinsic attempts to compute a
6528 target-specific value indicating the return address of the current function
6529 or one of its callers.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6530
6531<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6532<p>The argument to this intrinsic indicates which function to return the address
6533 for. Zero indicates the calling function, one indicates its caller, etc.
6534 The argument is <b>required</b> to be a constant integer value.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6535
6536<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6537<p>The '<tt>llvm.returnaddress</tt>' intrinsic either returns a pointer
6538 indicating the return address of the specified call frame, or zero if it
6539 cannot be identified. The value returned by this intrinsic is likely to be
6540 incorrect or 0 for arguments other than zero, so it should only be used for
6541 debugging purposes.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6542
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6543<p>Note that calling this intrinsic does not prevent function inlining or other
6544 aggressive transformations, so the value returned may not be that of the
6545 obvious source-language caller.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6546
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6547</div>
6548
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6549<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6550<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6551 <a name="int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6552</h4>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6553
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6554<div>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6555
6556<h5>Syntax:</h5>
6557<pre>
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]6558 declare i8* @llvm.frameaddress(i32 &lt;level&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6559</pre>
6560
6561<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6562<p>The '<tt>llvm.frameaddress</tt>' intrinsic attempts to return the
6563 target-specific frame pointer value for the specified stack frame.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6564
6565<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6566<p>The argument to this intrinsic indicates which function to return the frame
6567 pointer for. Zero indicates the calling function, one indicates its caller,
6568 etc. The argument is <b>required</b> to be a constant integer value.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6569
6570<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6571<p>The '<tt>llvm.frameaddress</tt>' intrinsic either returns a pointer
6572 indicating the frame address of the specified call frame, or zero if it
6573 cannot be identified. The value returned by this intrinsic is likely to be
6574 incorrect or 0 for arguments other than zero, so it should only be used for
6575 debugging purposes.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6576
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6577<p>Note that calling this intrinsic does not prevent function inlining or other
6578 aggressive transformations, so the value returned may not be that of the
6579 obvious source-language caller.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6580
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6581</div>
6582
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]6583<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6584<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6585 <a name="int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6586</h4>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]6587
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6588<div>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]6589
6590<h5>Syntax:</h5>
6591<pre>
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]6592 declare i8* @llvm.stacksave()
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]6593</pre>
6594
6595<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6596<p>The '<tt>llvm.stacksave</tt>' intrinsic is used to remember the current state
6597 of the function stack, for use
6598 with <a href="#int_stackrestore"> <tt>llvm.stackrestore</tt></a>. This is
6599 useful for implementing language features like scoped automatic variable
6600 sized arrays in C99.</p>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]6601
6602<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6603<p>This intrinsic returns a opaque pointer value that can be passed
6604 to <a href="#int_stackrestore"><tt>llvm.stackrestore</tt></a>. When
6605 an <tt>llvm.stackrestore</tt> intrinsic is executed with a value saved
6606 from <tt>llvm.stacksave</tt>, it effectively restores the state of the stack
6607 to the state it was in when the <tt>llvm.stacksave</tt> intrinsic executed.
6608 In practice, this pops any <a href="#i_alloca">alloca</a> blocks from the
6609 stack that were allocated after the <tt>llvm.stacksave</tt> was executed.</p>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]6610
6611</div>
6612
6613<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6614<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6615 <a name="int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6616</h4>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]6617
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6618<div>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]6619
6620<h5>Syntax:</h5>
6621<pre>
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]6622 declare void @llvm.stackrestore(i8* %ptr)
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]6623</pre>
6624
6625<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6626<p>The '<tt>llvm.stackrestore</tt>' intrinsic is used to restore the state of
6627 the function stack to the state it was in when the
6628 corresponding <a href="#int_stacksave"><tt>llvm.stacksave</tt></a> intrinsic
6629 executed. This is useful for implementing language features like scoped
6630 automatic variable sized arrays in C99.</p>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]6631
6632<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6633<p>See the description
6634 for <a href="#int_stacksave"><tt>llvm.stacksave</tt></a>.</p>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]6635
6636</div>
6637
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]6638<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6639<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6640 <a name="int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6641</h4>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]6642
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6643<div>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]6644
6645<h5>Syntax:</h5>
6646<pre>
Bruno Cardoso Lopes9a767332011-06-14 04:58:37 +0000[diff] [blame]6647 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]6648</pre>
6649
6650<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6651<p>The '<tt>llvm.prefetch</tt>' intrinsic is a hint to the code generator to
6652 insert a prefetch instruction if supported; otherwise, it is a noop.
6653 Prefetches have no effect on the behavior of the program but can change its
6654 performance characteristics.</p>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]6655
6656<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6657<p><tt>address</tt> is the address to be prefetched, <tt>rw</tt> is the
6658 specifier determining if the fetch should be for a read (0) or write (1),
6659 and <tt>locality</tt> is a temporal locality specifier ranging from (0) - no
Bruno Cardoso Lopes9a767332011-06-14 04:58:37 +0000[diff] [blame]6660 locality, to (3) - extremely local keep in cache. The <tt>cache type</tt>
6661 specifies whether the prefetch is performed on the data (1) or instruction (0)
6662 cache. The <tt>rw</tt>, <tt>locality</tt> and <tt>cache type</tt> arguments
6663 must be constant integers.</p>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]6664
6665<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6666<p>This intrinsic does not modify the behavior of the program. In particular,
6667 prefetches cannot trap and do not produce a value. On targets that support
6668 this intrinsic, the prefetch can provide hints to the processor cache for
6669 better performance.</p>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]6670
6671</div>
6672
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]6673<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6674<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6675 <a name="int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6676</h4>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]6677
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6678<div>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]6679
6680<h5>Syntax:</h5>
6681<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]6682 declare void @llvm.pcmarker(i32 &lt;id&gt;)
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]6683</pre>
6684
6685<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6686<p>The '<tt>llvm.pcmarker</tt>' intrinsic is a method to export a Program
6687 Counter (PC) in a region of code to simulators and other tools. The method
6688 is target specific, but it is expected that the marker will use exported
6689 symbols to transmit the PC of the marker. The marker makes no guarantees
6690 that it will remain with any specific instruction after optimizations. It is
6691 possible that the presence of a marker will inhibit optimizations. The
6692 intended use is to be inserted after optimizations to allow correlations of
6693 simulation runs.</p>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]6694
6695<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6696<p><tt>id</tt> is a numerical id identifying the marker.</p>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]6697
6698<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6699<p>This intrinsic does not modify the behavior of the program. Backends that do
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]6700 not support this intrinsic may ignore it.</p>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]6701
6702</div>
6703
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]6704<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6705<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6706 <a name="int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6707</h4>
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]6708
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6709<div>
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]6710
6711<h5>Syntax:</h5>
6712<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]6713 declare i64 @llvm.readcyclecounter()
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]6714</pre>
6715
6716<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6717<p>The '<tt>llvm.readcyclecounter</tt>' intrinsic provides access to the cycle
6718 counter register (or similar low latency, high accuracy clocks) on those
6719 targets that support it. On X86, it should map to RDTSC. On Alpha, it
6720 should map to RPCC. As the backing counters overflow quickly (on the order
6721 of 9 seconds on alpha), this should only be used for small timings.</p>
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]6722
6723<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6724<p>When directly supported, reading the cycle counter should not modify any
6725 memory. Implementations are allowed to either return a application specific
6726 value or a system wide value. On backends without support, this is lowered
6727 to a constant 0.</p>
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]6728
6729</div>
6730
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6731</div>
6732
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6733<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6734<h3>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6735 <a name="int_libc">Standard C Library Intrinsics</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6736</h3>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6737
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6738<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6739
6740<p>LLVM provides intrinsics for a few important standard C library functions.
6741 These intrinsics allow source-language front-ends to pass information about
6742 the alignment of the pointer arguments to the code generator, providing
6743 opportunity for more efficient code generation.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6744
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6745<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6746<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6747 <a name="int_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6748</h4>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6749
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6750<div>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6751
6752<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6753<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]6754 integer bit width and for different address spaces. Not all targets support
6755 all bit widths however.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6756
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6757<pre>
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]6758 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]6759 i32 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]6760 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]6761 i64 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6762</pre>
6763
6764<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6765<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
6766 source location to the destination location.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6767
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6768<p>Note that, unlike the standard libc function, the <tt>llvm.memcpy.*</tt>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6769 intrinsics do not return a value, takes extra alignment/isvolatile arguments
6770 and the pointers can be in specified address spaces.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6771
6772<h5>Arguments:</h5>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6773
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6774<p>The first argument is a pointer to the destination, the second is a pointer
6775 to the source. The third argument is an integer argument specifying the
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6776 number of bytes to copy, the fourth argument is the alignment of the
6777 source and destination locations, and the fifth is a boolean indicating a
6778 volatile access.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6779
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]6780<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]6781 then the caller guarantees that both the source and destination pointers are
6782 aligned to that boundary.</p>
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]6783
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]6784<p>If the <tt>isvolatile</tt> parameter is <tt>true</tt>, the
6785 <tt>llvm.memcpy</tt> call is a <a href="#volatile">volatile operation</a>.
6786 The detailed access behavior is not very cleanly specified and it is unwise
6787 to depend on it.</p>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6788
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6789<h5>Semantics:</h5>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6790
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6791<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
6792 source location to the destination location, which are not allowed to
6793 overlap. It copies "len" bytes of memory over. If the argument is known to
6794 be aligned to some boundary, this can be specified as the fourth argument,
6795 otherwise it should be set to 0 or 1.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6796
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6797</div>
6798
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6799<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6800<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6801 <a name="int_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6802</h4>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6803
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6804<div>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6805
6806<h5>Syntax:</h5>
Chris Lattner824b9582008-11-21 16:42:48 +0000[diff] [blame]6807<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]6808 width and for different address space. Not all targets support all bit
6809 widths however.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6810
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6811<pre>
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]6812 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]6813 i32 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]6814 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]6815 i64 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6816</pre>
6817
6818<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6819<p>The '<tt>llvm.memmove.*</tt>' intrinsics move a block of memory from the
6820 source location to the destination location. It is similar to the
6821 '<tt>llvm.memcpy</tt>' intrinsic but allows the two memory locations to
6822 overlap.</p>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6823
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6824<p>Note that, unlike the standard libc function, the <tt>llvm.memmove.*</tt>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6825 intrinsics do not return a value, takes extra alignment/isvolatile arguments
6826 and the pointers can be in specified address spaces.</p>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6827
6828<h5>Arguments:</h5>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6829
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6830<p>The first argument is a pointer to the destination, the second is a pointer
6831 to the source. The third argument is an integer argument specifying the
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6832 number of bytes to copy, the fourth argument is the alignment of the
6833 source and destination locations, and the fifth is a boolean indicating a
6834 volatile access.</p>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6835
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]6836<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]6837 then the caller guarantees that the source and destination pointers are
6838 aligned to that boundary.</p>
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]6839
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]6840<p>If the <tt>isvolatile</tt> parameter is <tt>true</tt>, the
6841 <tt>llvm.memmove</tt> call is a <a href="#volatile">volatile operation</a>.
6842 The detailed access behavior is not very cleanly specified and it is unwise
6843 to depend on it.</p>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6844
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6845<h5>Semantics:</h5>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6846
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6847<p>The '<tt>llvm.memmove.*</tt>' intrinsics copy a block of memory from the
6848 source location to the destination location, which may overlap. It copies
6849 "len" bytes of memory over. If the argument is known to be aligned to some
6850 boundary, this can be specified as the fourth argument, otherwise it should
6851 be set to 0 or 1.</p>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6852
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6853</div>
6854
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6855<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6856<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6857 <a name="int_memset">'<tt>llvm.memset.*</tt>' Intrinsics</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6858</h4>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6859
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6860<div>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6861
6862<h5>Syntax:</h5>
Chris Lattner824b9582008-11-21 16:42:48 +0000[diff] [blame]6863<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]6864 width and for different address spaces. However, not all targets support all
6865 bit widths.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6866
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6867<pre>
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]6868 declare void @llvm.memset.p0i8.i32(i8* &lt;dest&gt;, i8 &lt;val&gt;,
Chris Lattnerff35c3f2010-04-08 00:54:34 +0000[diff] [blame]6869 i32 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]6870 declare void @llvm.memset.p0i8.i64(i8* &lt;dest&gt;, i8 &lt;val&gt;,
Chris Lattnerff35c3f2010-04-08 00:54:34 +0000[diff] [blame]6871 i64 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6872</pre>
6873
6874<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6875<p>The '<tt>llvm.memset.*</tt>' intrinsics fill a block of memory with a
6876 particular byte value.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6877
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6878<p>Note that, unlike the standard libc function, the <tt>llvm.memset</tt>
John Criswellcdcbbfc2010-07-30 16:30:28 +0000[diff] [blame]6879 intrinsic does not return a value and takes extra alignment/volatile
6880 arguments. Also, the destination can be in an arbitrary address space.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6881
6882<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6883<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]6884 byte value with which to fill it, the third argument is an integer argument
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6885 specifying the number of bytes to fill, and the fourth argument is the known
John Criswellcdcbbfc2010-07-30 16:30:28 +0000[diff] [blame]6886 alignment of the destination location.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6887
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]6888<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]6889 then the caller guarantees that the destination pointer is aligned to that
6890 boundary.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6891
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]6892<p>If the <tt>isvolatile</tt> parameter is <tt>true</tt>, the
6893 <tt>llvm.memset</tt> call is a <a href="#volatile">volatile operation</a>.
6894 The detailed access behavior is not very cleanly specified and it is unwise
6895 to depend on it.</p>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6896
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6897<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6898<p>The '<tt>llvm.memset.*</tt>' intrinsics fill "len" bytes of memory starting
6899 at the destination location. If the argument is known to be aligned to some
6900 boundary, this can be specified as the fourth argument, otherwise it should
6901 be set to 0 or 1.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6902
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6903</div>
6904
Chris Lattner32006282004-06-11 02:28:03 +0000[diff] [blame]6905<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6906<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6907 <a name="int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6908</h4>
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]6909
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6910<div>
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]6911
6912<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6913<p>This is an overloaded intrinsic. You can use <tt>llvm.sqrt</tt> on any
6914 floating point or vector of floating point type. Not all targets support all
6915 types however.</p>
6916
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]6917<pre>
Dale Johannesen408f9c12007-10-02 17:47:38 +0000[diff] [blame]6918 declare float @llvm.sqrt.f32(float %Val)
6919 declare double @llvm.sqrt.f64(double %Val)
6920 declare x86_fp80 @llvm.sqrt.f80(x86_fp80 %Val)
6921 declare fp128 @llvm.sqrt.f128(fp128 %Val)
6922 declare ppc_fp128 @llvm.sqrt.ppcf128(ppc_fp128 %Val)
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]6923</pre>
6924
6925<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6926<p>The '<tt>llvm.sqrt</tt>' intrinsics return the sqrt of the specified operand,
6927 returning the same value as the libm '<tt>sqrt</tt>' functions would.
6928 Unlike <tt>sqrt</tt> in libm, however, <tt>llvm.sqrt</tt> has undefined
6929 behavior for negative numbers other than -0.0 (which allows for better
6930 optimization, because there is no need to worry about errno being
6931 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]6932
6933<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6934<p>The argument and return value are floating point numbers of the same
6935 type.</p>
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]6936
6937<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6938<p>This function returns the sqrt of the specified operand if it is a
6939 nonnegative floating point number.</p>
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]6940
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]6941</div>
6942
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6943<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6944<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6945 <a name="int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6946</h4>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6947
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6948<div>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6949
6950<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6951<p>This is an overloaded intrinsic. You can use <tt>llvm.powi</tt> on any
6952 floating point or vector of floating point type. Not all targets support all
6953 types however.</p>
6954
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6955<pre>
Dale Johannesen408f9c12007-10-02 17:47:38 +0000[diff] [blame]6956 declare float @llvm.powi.f32(float %Val, i32 %power)
6957 declare double @llvm.powi.f64(double %Val, i32 %power)
6958 declare x86_fp80 @llvm.powi.f80(x86_fp80 %Val, i32 %power)
6959 declare fp128 @llvm.powi.f128(fp128 %Val, i32 %power)
6960 declare ppc_fp128 @llvm.powi.ppcf128(ppc_fp128 %Val, i32 %power)
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6961</pre>
6962
6963<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6964<p>The '<tt>llvm.powi.*</tt>' intrinsics return the first operand raised to the
6965 specified (positive or negative) power. The order of evaluation of
6966 multiplications is not defined. When a vector of floating point type is
6967 used, the second argument remains a scalar integer value.</p>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6968
6969<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6970<p>The second argument is an integer power, and the first is a value to raise to
6971 that power.</p>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6972
6973<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6974<p>This function returns the first value raised to the second power with an
6975 unspecified sequence of rounding operations.</p>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6976
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6977</div>
6978
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6979<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6980<h4>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6981 <a name="int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6982</h4>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6983
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6984<div>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6985
6986<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6987<p>This is an overloaded intrinsic. You can use <tt>llvm.sin</tt> on any
6988 floating point or vector of floating point type. Not all targets support all
6989 types however.</p>
6990
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6991<pre>
6992 declare float @llvm.sin.f32(float %Val)
6993 declare double @llvm.sin.f64(double %Val)
6994 declare x86_fp80 @llvm.sin.f80(x86_fp80 %Val)
6995 declare fp128 @llvm.sin.f128(fp128 %Val)
6996 declare ppc_fp128 @llvm.sin.ppcf128(ppc_fp128 %Val)
6997</pre>
6998
6999<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7000<p>The '<tt>llvm.sin.*</tt>' intrinsics return the sine of the operand.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7001
7002<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7003<p>The argument and return value are floating point numbers of the same
7004 type.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7005
7006<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7007<p>This function returns the sine of the specified operand, returning the same
7008 values as the libm <tt>sin</tt> functions would, and handles error conditions
7009 in the same way.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7010
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7011</div>
7012
7013<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7014<h4>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7015 <a name="int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7016</h4>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7017
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7018<div>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7019
7020<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7021<p>This is an overloaded intrinsic. You can use <tt>llvm.cos</tt> on any
7022 floating point or vector of floating point type. Not all targets support all
7023 types however.</p>
7024
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7025<pre>
7026 declare float @llvm.cos.f32(float %Val)
7027 declare double @llvm.cos.f64(double %Val)
7028 declare x86_fp80 @llvm.cos.f80(x86_fp80 %Val)
7029 declare fp128 @llvm.cos.f128(fp128 %Val)
7030 declare ppc_fp128 @llvm.cos.ppcf128(ppc_fp128 %Val)
7031</pre>
7032
7033<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7034<p>The '<tt>llvm.cos.*</tt>' intrinsics return the cosine of the operand.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7035
7036<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7037<p>The argument and return value are floating point numbers of the same
7038 type.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7039
7040<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7041<p>This function returns the cosine of the specified operand, returning the same
7042 values as the libm <tt>cos</tt> functions would, and handles error conditions
7043 in the same way.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7044
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7045</div>
7046
7047<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7048<h4>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7049 <a name="int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7050</h4>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7051
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7052<div>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7053
7054<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7055<p>This is an overloaded intrinsic. You can use <tt>llvm.pow</tt> on any
7056 floating point or vector of floating point type. Not all targets support all
7057 types however.</p>
7058
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7059<pre>
7060 declare float @llvm.pow.f32(float %Val, float %Power)
7061 declare double @llvm.pow.f64(double %Val, double %Power)
7062 declare x86_fp80 @llvm.pow.f80(x86_fp80 %Val, x86_fp80 %Power)
7063 declare fp128 @llvm.pow.f128(fp128 %Val, fp128 %Power)
7064 declare ppc_fp128 @llvm.pow.ppcf128(ppc_fp128 %Val, ppc_fp128 Power)
7065</pre>
7066
7067<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7068<p>The '<tt>llvm.pow.*</tt>' intrinsics return the first operand raised to the
7069 specified (positive or negative) power.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7070
7071<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7072<p>The second argument is a floating point power, and the first is a value to
7073 raise to that power.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7074
7075<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7076<p>This function returns the first value raised to the second power, returning
7077 the same values as the libm <tt>pow</tt> functions would, and handles error
7078 conditions in the same way.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7079
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7080</div>
7081
Dan Gohman4e9011c2011-05-23 21:13:03 +0000[diff] [blame]7082<!-- _______________________________________________________________________ -->
7083<h4>
7084 <a name="int_exp">'<tt>llvm.exp.*</tt>' Intrinsic</a>
7085</h4>
7086
7087<div>
7088
7089<h5>Syntax:</h5>
7090<p>This is an overloaded intrinsic. You can use <tt>llvm.exp</tt> on any
7091 floating point or vector of floating point type. Not all targets support all
7092 types however.</p>
7093
7094<pre>
7095 declare float @llvm.exp.f32(float %Val)
7096 declare double @llvm.exp.f64(double %Val)
7097 declare x86_fp80 @llvm.exp.f80(x86_fp80 %Val)
7098 declare fp128 @llvm.exp.f128(fp128 %Val)
7099 declare ppc_fp128 @llvm.exp.ppcf128(ppc_fp128 %Val)
7100</pre>
7101
7102<h5>Overview:</h5>
7103<p>The '<tt>llvm.exp.*</tt>' intrinsics perform the exp function.</p>
7104
7105<h5>Arguments:</h5>
7106<p>The argument and return value are floating point numbers of the same
7107 type.</p>
7108
7109<h5>Semantics:</h5>
7110<p>This function returns the same values as the libm <tt>exp</tt> functions
7111 would, and handles error conditions in the same way.</p>
7112
7113</div>
7114
7115<!-- _______________________________________________________________________ -->
7116<h4>
7117 <a name="int_log">'<tt>llvm.log.*</tt>' Intrinsic</a>
7118</h4>
7119
7120<div>
7121
7122<h5>Syntax:</h5>
7123<p>This is an overloaded intrinsic. You can use <tt>llvm.log</tt> on any
7124 floating point or vector of floating point type. Not all targets support all
7125 types however.</p>
7126
7127<pre>
7128 declare float @llvm.log.f32(float %Val)
7129 declare double @llvm.log.f64(double %Val)
7130 declare x86_fp80 @llvm.log.f80(x86_fp80 %Val)
7131 declare fp128 @llvm.log.f128(fp128 %Val)
7132 declare ppc_fp128 @llvm.log.ppcf128(ppc_fp128 %Val)
7133</pre>
7134
7135<h5>Overview:</h5>
7136<p>The '<tt>llvm.log.*</tt>' intrinsics perform the log function.</p>
7137
7138<h5>Arguments:</h5>
7139<p>The argument and return value are floating point numbers of the same
7140 type.</p>
7141
7142<h5>Semantics:</h5>
7143<p>This function returns the same values as the libm <tt>log</tt> functions
7144 would, and handles error conditions in the same way.</p>
7145
Nick Lewycky1c929be2011-10-31 01:32:21 +0000[diff] [blame]7146</div>
7147
7148<!-- _______________________________________________________________________ -->
Cameron Zwarich33390842011-07-08 21:39:21 +0000[diff] [blame]7149<h4>
7150 <a name="int_fma">'<tt>llvm.fma.*</tt>' Intrinsic</a>
7151</h4>
7152
7153<div>
7154
7155<h5>Syntax:</h5>
7156<p>This is an overloaded intrinsic. You can use <tt>llvm.fma</tt> on any
7157 floating point or vector of floating point type. Not all targets support all
7158 types however.</p>
7159
7160<pre>
7161 declare float @llvm.fma.f32(float %a, float %b, float %c)
7162 declare double @llvm.fma.f64(double %a, double %b, double %c)
7163 declare x86_fp80 @llvm.fma.f80(x86_fp80 %a, x86_fp80 %b, x86_fp80 %c)
7164 declare fp128 @llvm.fma.f128(fp128 %a, fp128 %b, fp128 %c)
7165 declare ppc_fp128 @llvm.fma.ppcf128(ppc_fp128 %a, ppc_fp128 %b, ppc_fp128 %c)
7166</pre>
7167
7168<h5>Overview:</h5>
Cameron Zwarichabc43e62011-07-08 22:13:55 +0000[diff] [blame]7169<p>The '<tt>llvm.fma.*</tt>' intrinsics perform the fused multiply-add
Cameron Zwarich33390842011-07-08 21:39:21 +0000[diff] [blame]7170 operation.</p>
7171
7172<h5>Arguments:</h5>
7173<p>The argument and return value are floating point numbers of the same
7174 type.</p>
7175
7176<h5>Semantics:</h5>
7177<p>This function returns the same values as the libm <tt>fma</tt> functions
7178 would.</p>
7179
Dan Gohman4e9011c2011-05-23 21:13:03 +0000[diff] [blame]7180</div>
7181
NAKAMURA Takumi4b2e07a2011-10-31 13:04:26 +0000[diff] [blame]7182</div>
7183
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7184<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7185<h3>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]7186 <a name="int_manip">Bit Manipulation Intrinsics</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7187</h3>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7188
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7189<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7190
7191<p>LLVM provides intrinsics for a few important bit manipulation operations.
7192 These allow efficient code generation for some algorithms.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7193
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7194<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7195<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]7196 <a name="int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7197</h4>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]7198
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7199<div>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]7200
7201<h5>Syntax:</h5>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]7202<p>This is an overloaded intrinsic function. You can use bswap on any integer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7203 type that is an even number of bytes (i.e. BitWidth % 16 == 0).</p>
7204
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]7205<pre>
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]7206 declare i16 @llvm.bswap.i16(i16 &lt;id&gt;)
7207 declare i32 @llvm.bswap.i32(i32 &lt;id&gt;)
7208 declare i64 @llvm.bswap.i64(i64 &lt;id&gt;)
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]7209</pre>
7210
7211<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7212<p>The '<tt>llvm.bswap</tt>' family of intrinsics is used to byte swap integer
7213 values with an even number of bytes (positive multiple of 16 bits). These
7214 are useful for performing operations on data that is not in the target's
7215 native byte order.</p>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]7216
7217<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7218<p>The <tt>llvm.bswap.i16</tt> intrinsic returns an i16 value that has the high
7219 and low byte of the input i16 swapped. Similarly,
7220 the <tt>llvm.bswap.i32</tt> intrinsic returns an i32 value that has the four
7221 bytes of the input i32 swapped, so that if the input bytes are numbered 0, 1,
7222 2, 3 then the returned i32 will have its bytes in 3, 2, 1, 0 order.
7223 The <tt>llvm.bswap.i48</tt>, <tt>llvm.bswap.i64</tt> and other intrinsics
7224 extend this concept to additional even-byte lengths (6 bytes, 8 bytes and
7225 more, respectively).</p>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]7226
7227</div>
7228
7229<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7230<h4>
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]7231 <a name="int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7232</h4>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7233
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7234<div>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7235
7236<h5>Syntax:</h5>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]7237<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]7238 width, or on any vector with integer elements. Not all targets support all
7239 bit widths or vector types, however.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7240
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7241<pre>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7242 declare i8 @llvm.ctpop.i8(i8 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]7243 declare i16 @llvm.ctpop.i16(i16 &lt;src&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]7244 declare i32 @llvm.ctpop.i32(i32 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]7245 declare i64 @llvm.ctpop.i64(i64 &lt;src&gt;)
7246 declare i256 @llvm.ctpop.i256(i256 &lt;src&gt;)
Owen Andersonf1ac4652011-07-01 21:52:38 +0000[diff] [blame]7247 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]7248</pre>
7249
7250<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7251<p>The '<tt>llvm.ctpop</tt>' family of intrinsics counts the number of bits set
7252 in a value.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7253
7254<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7255<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]7256 integer type, or a vector with integer elements.
7257 The return type must match the argument type.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7258
7259<h5>Semantics:</h5>
Owen Andersonf1ac4652011-07-01 21:52:38 +0000[diff] [blame]7260<p>The '<tt>llvm.ctpop</tt>' intrinsic counts the 1's in a variable, or within each
7261 element of a vector.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7262
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7263</div>
7264
7265<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7266<h4>
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]7267 <a name="int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7268</h4>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7269
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7270<div>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7271
7272<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7273<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]7274 integer bit width, or any vector whose elements are integers. Not all
7275 targets support all bit widths or vector types, however.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7276
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7277<pre>
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]7278 declare i8 @llvm.ctlz.i8 (i8 &lt;src&gt;)
7279 declare i16 @llvm.ctlz.i16(i16 &lt;src&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]7280 declare i32 @llvm.ctlz.i32(i32 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]7281 declare i64 @llvm.ctlz.i64(i64 &lt;src&gt;)
7282 declare i256 @llvm.ctlz.i256(i256 &lt;src&gt;)
Owen Andersonf1ac4652011-07-01 21:52:38 +0000[diff] [blame]7283 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]7284</pre>
7285
7286<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7287<p>The '<tt>llvm.ctlz</tt>' family of intrinsic functions counts the number of
7288 leading zeros in a variable.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7289
7290<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7291<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]7292 integer type, or any vector type with integer element type.
7293 The return type must match the argument type.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7294
7295<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7296<p>The '<tt>llvm.ctlz</tt>' intrinsic counts the leading (most significant)
Owen Andersonf1ac4652011-07-01 21:52:38 +0000[diff] [blame]7297 zeros in a variable, or within each element of the vector if the operation
7298 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]7299 the type of src. For example, <tt>llvm.ctlz(i32 2) = 30</tt>.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7300
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7301</div>
Chris Lattner32006282004-06-11 02:28:03 +0000[diff] [blame]7302
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]7303<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7304<h4>
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]7305 <a name="int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7306</h4>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]7307
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7308<div>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]7309
7310<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7311<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]7312 integer bit width, or any vector of integer elements. Not all targets
7313 support all bit widths or vector types, however.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7314
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]7315<pre>
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]7316 declare i8 @llvm.cttz.i8 (i8 &lt;src&gt;)
7317 declare i16 @llvm.cttz.i16(i16 &lt;src&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]7318 declare i32 @llvm.cttz.i32(i32 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]7319 declare i64 @llvm.cttz.i64(i64 &lt;src&gt;)
7320 declare i256 @llvm.cttz.i256(i256 &lt;src&gt;)
Owen Andersonf1ac4652011-07-01 21:52:38 +0000[diff] [blame]7321 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]7322</pre>
7323
7324<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7325<p>The '<tt>llvm.cttz</tt>' family of intrinsic functions counts the number of
7326 trailing zeros.</p>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]7327
7328<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7329<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]7330 integer type, or a vectory with integer element type.. The return type
7331 must match the argument type.</p>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]7332
7333<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7334<p>The '<tt>llvm.cttz</tt>' intrinsic counts the trailing (least significant)
Owen Andersonf1ac4652011-07-01 21:52:38 +0000[diff] [blame]7335 zeros in a variable, or within each element of a vector.
7336 If the src == 0 then the result is the size in bits of
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7337 the type of src. For example, <tt>llvm.cttz(2) = 1</tt>.</p>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]7338
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]7339</div>
7340
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7341</div>
7342
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]7343<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7344<h3>
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]7345 <a name="int_overflow">Arithmetic with Overflow Intrinsics</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7346</h3>
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]7347
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7348<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7349
7350<p>LLVM provides intrinsics for some arithmetic with overflow operations.</p>
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]7351
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7352<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7353<h4>
7354 <a name="int_sadd_overflow">
7355 '<tt>llvm.sadd.with.overflow.*</tt>' Intrinsics
7356 </a>
7357</h4>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7358
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7359<div>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7360
7361<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7362<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]7363 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7364
7365<pre>
7366 declare {i16, i1} @llvm.sadd.with.overflow.i16(i16 %a, i16 %b)
7367 declare {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
7368 declare {i64, i1} @llvm.sadd.with.overflow.i64(i64 %a, i64 %b)
7369</pre>
7370
7371<h5>Overview:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7372<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7373 a signed addition of the two arguments, and indicate whether an overflow
7374 occurred during the signed summation.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7375
7376<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7377<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]7378 be of integer types of any bit width, but they must have the same bit
7379 width. The second element of the result structure must be of
7380 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
7381 undergo signed addition.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7382
7383<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7384<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7385 a signed addition of the two variables. They return a structure &mdash; the
7386 first element of which is the signed summation, and the second element of
7387 which is a bit specifying if the signed summation resulted in an
7388 overflow.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7389
7390<h5>Examples:</h5>
7391<pre>
7392 %res = call {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
7393 %sum = extractvalue {i32, i1} %res, 0
7394 %obit = extractvalue {i32, i1} %res, 1
7395 br i1 %obit, label %overflow, label %normal
7396</pre>
7397
7398</div>
7399
7400<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7401<h4>
7402 <a name="int_uadd_overflow">
7403 '<tt>llvm.uadd.with.overflow.*</tt>' Intrinsics
7404 </a>
7405</h4>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7406
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7407<div>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7408
7409<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7410<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]7411 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7412
7413<pre>
7414 declare {i16, i1} @llvm.uadd.with.overflow.i16(i16 %a, i16 %b)
7415 declare {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
7416 declare {i64, i1} @llvm.uadd.with.overflow.i64(i64 %a, i64 %b)
7417</pre>
7418
7419<h5>Overview:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7420<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7421 an unsigned addition of the two arguments, and indicate whether a carry
7422 occurred during the unsigned summation.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7423
7424<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7425<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]7426 be of integer types of any bit width, but they must have the same bit
7427 width. The second element of the result structure must be of
7428 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
7429 undergo unsigned addition.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7430
7431<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7432<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7433 an unsigned addition of the two arguments. They return a structure &mdash;
7434 the first element of which is the sum, and the second element of which is a
7435 bit specifying if the unsigned summation resulted in a carry.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7436
7437<h5>Examples:</h5>
7438<pre>
7439 %res = call {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
7440 %sum = extractvalue {i32, i1} %res, 0
7441 %obit = extractvalue {i32, i1} %res, 1
7442 br i1 %obit, label %carry, label %normal
7443</pre>
7444
7445</div>
7446
7447<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7448<h4>
7449 <a name="int_ssub_overflow">
7450 '<tt>llvm.ssub.with.overflow.*</tt>' Intrinsics
7451 </a>
7452</h4>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7453
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7454<div>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7455
7456<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7457<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]7458 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7459
7460<pre>
7461 declare {i16, i1} @llvm.ssub.with.overflow.i16(i16 %a, i16 %b)
7462 declare {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
7463 declare {i64, i1} @llvm.ssub.with.overflow.i64(i64 %a, i64 %b)
7464</pre>
7465
7466<h5>Overview:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7467<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7468 a signed subtraction of the two arguments, and indicate whether an overflow
7469 occurred during the signed subtraction.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7470
7471<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7472<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]7473 be of integer types of any bit width, but they must have the same bit
7474 width. The second element of the result structure must be of
7475 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
7476 undergo signed subtraction.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7477
7478<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7479<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7480 a signed subtraction of the two arguments. They return a structure &mdash;
7481 the first element of which is the subtraction, and the second element of
7482 which is a bit specifying if the signed subtraction resulted in an
7483 overflow.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7484
7485<h5>Examples:</h5>
7486<pre>
7487 %res = call {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
7488 %sum = extractvalue {i32, i1} %res, 0
7489 %obit = extractvalue {i32, i1} %res, 1
7490 br i1 %obit, label %overflow, label %normal
7491</pre>
7492
7493</div>
7494
7495<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7496<h4>
7497 <a name="int_usub_overflow">
7498 '<tt>llvm.usub.with.overflow.*</tt>' Intrinsics
7499 </a>
7500</h4>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7501
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7502<div>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7503
7504<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7505<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]7506 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7507
7508<pre>
7509 declare {i16, i1} @llvm.usub.with.overflow.i16(i16 %a, i16 %b)
7510 declare {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
7511 declare {i64, i1} @llvm.usub.with.overflow.i64(i64 %a, i64 %b)
7512</pre>
7513
7514<h5>Overview:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7515<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7516 an unsigned subtraction of the two arguments, and indicate whether an
7517 overflow occurred during the unsigned subtraction.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7518
7519<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7520<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]7521 be of integer types of any bit width, but they must have the same bit
7522 width. The second element of the result structure must be of
7523 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
7524 undergo unsigned subtraction.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7525
7526<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7527<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7528 an unsigned subtraction of the two arguments. They return a structure &mdash;
7529 the first element of which is the subtraction, and the second element of
7530 which is a bit specifying if the unsigned subtraction resulted in an
7531 overflow.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7532
7533<h5>Examples:</h5>
7534<pre>
7535 %res = call {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
7536 %sum = extractvalue {i32, i1} %res, 0
7537 %obit = extractvalue {i32, i1} %res, 1
7538 br i1 %obit, label %overflow, label %normal
7539</pre>
7540
7541</div>
7542
7543<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7544<h4>
7545 <a name="int_smul_overflow">
7546 '<tt>llvm.smul.with.overflow.*</tt>' Intrinsics
7547 </a>
7548</h4>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7549
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7550<div>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7551
7552<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7553<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]7554 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7555
7556<pre>
7557 declare {i16, i1} @llvm.smul.with.overflow.i16(i16 %a, i16 %b)
7558 declare {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
7559 declare {i64, i1} @llvm.smul.with.overflow.i64(i64 %a, i64 %b)
7560</pre>
7561
7562<h5>Overview:</h5>
7563
7564<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7565 a signed multiplication of the two arguments, and indicate whether an
7566 overflow occurred during the signed multiplication.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7567
7568<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7569<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]7570 be of integer types of any bit width, but they must have the same bit
7571 width. The second element of the result structure must be of
7572 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
7573 undergo signed multiplication.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7574
7575<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7576<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7577 a signed multiplication of the two arguments. They return a structure &mdash;
7578 the first element of which is the multiplication, and the second element of
7579 which is a bit specifying if the signed multiplication resulted in an
7580 overflow.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7581
7582<h5>Examples:</h5>
7583<pre>
7584 %res = call {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
7585 %sum = extractvalue {i32, i1} %res, 0
7586 %obit = extractvalue {i32, i1} %res, 1
7587 br i1 %obit, label %overflow, label %normal
7588</pre>
7589
Reid Spencerf86037f2007-04-11 23:23:49 +0000[diff] [blame]7590</div>
7591
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]7592<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7593<h4>
7594 <a name="int_umul_overflow">
7595 '<tt>llvm.umul.with.overflow.*</tt>' Intrinsics
7596 </a>
7597</h4>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]7598
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7599<div>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]7600
7601<h5>Syntax:</h5>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]7602<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]7603 on any integer bit width.</p>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]7604
7605<pre>
7606 declare {i16, i1} @llvm.umul.with.overflow.i16(i16 %a, i16 %b)
7607 declare {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
7608 declare {i64, i1} @llvm.umul.with.overflow.i64(i64 %a, i64 %b)
7609</pre>
7610
7611<h5>Overview:</h5>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]7612<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7613 a unsigned multiplication of the two arguments, and indicate whether an
7614 overflow occurred during the unsigned multiplication.</p>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]7615
7616<h5>Arguments:</h5>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]7617<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]7618 be of integer types of any bit width, but they must have the same bit
7619 width. The second element of the result structure must be of
7620 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
7621 undergo unsigned multiplication.</p>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]7622
7623<h5>Semantics:</h5>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]7624<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7625 an unsigned multiplication of the two arguments. They return a structure
7626 &mdash; the first element of which is the multiplication, and the second
7627 element of which is a bit specifying if the unsigned multiplication resulted
7628 in an overflow.</p>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]7629
7630<h5>Examples:</h5>
7631<pre>
7632 %res = call {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
7633 %sum = extractvalue {i32, i1} %res, 0
7634 %obit = extractvalue {i32, i1} %res, 1
7635 br i1 %obit, label %overflow, label %normal
7636</pre>
7637
7638</div>
7639
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7640</div>
7641
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]7642<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7643<h3>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]7644 <a name="int_fp16">Half Precision Floating Point Intrinsics</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7645</h3>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]7646
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7647<div>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]7648
Chris Lattner0cec9c82010-03-15 04:12:21 +0000[diff] [blame]7649<p>Half precision floating point is a storage-only format. This means that it is
7650 a dense encoding (in memory) but does not support computation in the
7651 format.</p>
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]7652
Chris Lattner0cec9c82010-03-15 04:12:21 +0000[diff] [blame]7653<p>This means that code must first load the half-precision floating point
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]7654 value as an i16, then convert it to float with <a
7655 href="#int_convert_from_fp16"><tt>llvm.convert.from.fp16</tt></a>.
7656 Computation can then be performed on the float value (including extending to
Chris Lattner0cec9c82010-03-15 04:12:21 +0000[diff] [blame]7657 double etc). To store the value back to memory, it is first converted to
7658 float if needed, then converted to i16 with
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]7659 <a href="#int_convert_to_fp16"><tt>llvm.convert.to.fp16</tt></a>, then
7660 storing as an i16 value.</p>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]7661
7662<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7663<h4>
7664 <a name="int_convert_to_fp16">
7665 '<tt>llvm.convert.to.fp16</tt>' Intrinsic
7666 </a>
7667</h4>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]7668
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7669<div>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]7670
7671<h5>Syntax:</h5>
7672<pre>
7673 declare i16 @llvm.convert.to.fp16(f32 %a)
7674</pre>
7675
7676<h5>Overview:</h5>
7677<p>The '<tt>llvm.convert.to.fp16</tt>' intrinsic function performs
7678 a conversion from single precision floating point format to half precision
7679 floating point format.</p>
7680
7681<h5>Arguments:</h5>
7682<p>The intrinsic function contains single argument - the value to be
7683 converted.</p>
7684
7685<h5>Semantics:</h5>
7686<p>The '<tt>llvm.convert.to.fp16</tt>' intrinsic function performs
7687 a conversion from single precision floating point format to half precision
Chris Lattner0cec9c82010-03-15 04:12:21 +0000[diff] [blame]7688 floating point format. The return value is an <tt>i16</tt> which
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]7689 contains the converted number.</p>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]7690
7691<h5>Examples:</h5>
7692<pre>
7693 %res = call i16 @llvm.convert.to.fp16(f32 %a)
7694 store i16 %res, i16* @x, align 2
7695</pre>
7696
7697</div>
7698
7699<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7700<h4>
7701 <a name="int_convert_from_fp16">
7702 '<tt>llvm.convert.from.fp16</tt>' Intrinsic
7703 </a>
7704</h4>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]7705
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7706<div>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]7707
7708<h5>Syntax:</h5>
7709<pre>
7710 declare f32 @llvm.convert.from.fp16(i16 %a)
7711</pre>
7712
7713<h5>Overview:</h5>
7714<p>The '<tt>llvm.convert.from.fp16</tt>' intrinsic function performs
7715 a conversion from half precision floating point format to single precision
7716 floating point format.</p>
7717
7718<h5>Arguments:</h5>
7719<p>The intrinsic function contains single argument - the value to be
7720 converted.</p>
7721
7722<h5>Semantics:</h5>
7723<p>The '<tt>llvm.convert.from.fp16</tt>' intrinsic function performs a
Chris Lattner0cec9c82010-03-15 04:12:21 +0000[diff] [blame]7724 conversion from half single precision floating point format to single
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]7725 precision floating point format. The input half-float value is represented by
7726 an <tt>i16</tt> value.</p>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]7727
7728<h5>Examples:</h5>
7729<pre>
7730 %a = load i16* @x, align 2
7731 %res = call f32 @llvm.convert.from.fp16(i16 %a)
7732</pre>
7733
7734</div>
7735
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7736</div>
7737
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]7738<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7739<h3>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]7740 <a name="int_debugger">Debugger Intrinsics</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7741</h3>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]7742
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7743<div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]7744
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7745<p>The LLVM debugger intrinsics (which all start with <tt>llvm.dbg.</tt>
7746 prefix), are described in
7747 the <a href="SourceLevelDebugging.html#format_common_intrinsics">LLVM Source
7748 Level Debugging</a> document.</p>
7749
7750</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]7751
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]7752<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7753<h3>
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]7754 <a name="int_eh">Exception Handling Intrinsics</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7755</h3>
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]7756
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7757<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7758
7759<p>The LLVM exception handling intrinsics (which all start with
7760 <tt>llvm.eh.</tt> prefix), are described in
7761 the <a href="ExceptionHandling.html#format_common_intrinsics">LLVM Exception
7762 Handling</a> document.</p>
7763
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]7764</div>
7765
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]7766<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7767<h3>
Duncan Sands4a544a72011-09-06 13:37:06 +0000[diff] [blame]7768 <a name="int_trampoline">Trampoline Intrinsics</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7769</h3>
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]7770
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7771<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7772
Duncan Sands4a544a72011-09-06 13:37:06 +0000[diff] [blame]7773<p>These intrinsics make it possible to excise one parameter, marked with
Dan Gohmanff235352010-07-02 23:18:08 +0000[diff] [blame]7774 the <a href="#nest"><tt>nest</tt></a> attribute, from a function.
7775 The result is a callable
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7776 function pointer lacking the nest parameter - the caller does not need to
7777 provide a value for it. Instead, the value to use is stored in advance in a
7778 "trampoline", a block of memory usually allocated on the stack, which also
7779 contains code to splice the nest value into the argument list. This is used
7780 to implement the GCC nested function address extension.</p>
7781
7782<p>For example, if the function is
7783 <tt>i32 f(i8* nest %c, i32 %x, i32 %y)</tt> then the resulting function
7784 pointer has signature <tt>i32 (i32, i32)*</tt>. It can be created as
7785 follows:</p>
7786
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]7787<pre class="doc_code">
Duncan Sandsf7331b32007-09-11 14:10:23 +0000[diff] [blame]7788 %tramp = alloca [10 x i8], align 4 ; size and alignment only correct for X86
7789 %tramp1 = getelementptr [10 x i8]* %tramp, i32 0, i32 0
Duncan Sands4a544a72011-09-06 13:37:06 +0000[diff] [blame]7790 call i8* @llvm.init.trampoline(i8* %tramp1, i8* bitcast (i32 (i8*, i32, i32)* @f to i8*), i8* %nval)
7791 %p = call i8* @llvm.adjust.trampoline(i8* %tramp1)
Duncan Sandsf7331b32007-09-11 14:10:23 +0000[diff] [blame]7792 %fp = bitcast i8* %p to i32 (i32, i32)*
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]7793</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7794
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7795<p>The call <tt>%val = call i32 %fp(i32 %x, i32 %y)</tt> is then equivalent
7796 to <tt>%val = call i32 %f(i8* %nval, i32 %x, i32 %y)</tt>.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7797
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]7798<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7799<h4>
7800 <a name="int_it">
7801 '<tt>llvm.init.trampoline</tt>' Intrinsic
7802 </a>
7803</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7804
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7805<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7806
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]7807<h5>Syntax:</h5>
7808<pre>
Duncan Sands4a544a72011-09-06 13:37:06 +0000[diff] [blame]7809 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]7810</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7811
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]7812<h5>Overview:</h5>
Duncan Sands4a544a72011-09-06 13:37:06 +0000[diff] [blame]7813<p>This fills the memory pointed to by <tt>tramp</tt> with executable code,
7814 turning it into a trampoline.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7815
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]7816<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7817<p>The <tt>llvm.init.trampoline</tt> intrinsic takes three arguments, all
7818 pointers. The <tt>tramp</tt> argument must point to a sufficiently large and
7819 sufficiently aligned block of memory; this memory is written to by the
7820 intrinsic. Note that the size and the alignment are target-specific - LLVM
7821 currently provides no portable way of determining them, so a front-end that
7822 generates this intrinsic needs to have some target-specific knowledge.
7823 The <tt>func</tt> argument must hold a function bitcast to
7824 an <tt>i8*</tt>.</p>
7825
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]7826<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7827<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]7828 dependent code, turning it into a function. Then <tt>tramp</tt> needs to be
7829 passed to <a href="#int_at">llvm.adjust.trampoline</a> to get a pointer
7830 which can be <a href="#int_trampoline">bitcast (to a new function) and
7831 called</a>. The new function's signature is the same as that of
7832 <tt>func</tt> with any arguments marked with the <tt>nest</tt> attribute
7833 removed. At most one such <tt>nest</tt> argument is allowed, and it must be of
7834 pointer type. Calling the new function is equivalent to calling <tt>func</tt>
7835 with the same argument list, but with <tt>nval</tt> used for the missing
7836 <tt>nest</tt> argument. If, after calling <tt>llvm.init.trampoline</tt>, the
7837 memory pointed to by <tt>tramp</tt> is modified, then the effect of any later call
7838 to the returned function pointer is undefined.</p>
7839</div>
7840
7841<!-- _______________________________________________________________________ -->
7842<h4>
7843 <a name="int_at">
7844 '<tt>llvm.adjust.trampoline</tt>' Intrinsic
7845 </a>
7846</h4>
7847
7848<div>
7849
7850<h5>Syntax:</h5>
7851<pre>
7852 declare i8* @llvm.adjust.trampoline(i8* &lt;tramp&gt;)
7853</pre>
7854
7855<h5>Overview:</h5>
7856<p>This performs any required machine-specific adjustment to the address of a
7857 trampoline (passed as <tt>tramp</tt>).</p>
7858
7859<h5>Arguments:</h5>
7860<p><tt>tramp</tt> must point to a block of memory which already has trampoline code
7861 filled in by a previous call to <a href="#int_it"><tt>llvm.init.trampoline</tt>
7862 </a>.</p>
7863
7864<h5>Semantics:</h5>
7865<p>On some architectures the address of the code to be executed needs to be
7866 different to the address where the trampoline is actually stored. This
7867 intrinsic returns the executable address corresponding to <tt>tramp</tt>
7868 after performing the required machine specific adjustments.
7869 The pointer returned can then be <a href="#int_trampoline"> bitcast and
7870 executed</a>.
7871</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7872
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]7873</div>
7874
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7875</div>
7876
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]7877<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7878<h3>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7879 <a name="int_memorymarkers">Memory Use Markers</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7880</h3>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7881
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7882<div>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7883
7884<p>This class of intrinsics exists to information about the lifetime of memory
7885 objects and ranges where variables are immutable.</p>
7886
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]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_start">'<tt>llvm.lifetime.start</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.start(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7897</pre>
7898
7899<h5>Overview:</h5>
7900<p>The '<tt>llvm.lifetime.start</tt>' intrinsic specifies the start 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 before 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
Nick Lewycky8d336592009-10-27 16:56:58 +0000[diff] [blame]7911 never be used and has an undefined value. A load from the pointer that
7912 precedes this intrinsic can be replaced with
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7913 <tt>'<a href="#undefvalues">undef</a>'</tt>.</p>
7914
7915</div>
7916
7917<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7918<h4>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7919 <a name="int_lifetime_end">'<tt>llvm.lifetime.end</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7920</h4>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7921
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7922<div>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7923
7924<h5>Syntax:</h5>
7925<pre>
7926 declare void @llvm.lifetime.end(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7927</pre>
7928
7929<h5>Overview:</h5>
7930<p>The '<tt>llvm.lifetime.end</tt>' intrinsic specifies the end of a memory
7931 object's lifetime.</p>
7932
7933<h5>Arguments:</h5>
Nick Lewycky321333e2009-10-13 07:57:33 +0000[diff] [blame]7934<p>The first argument is a constant integer representing the size of the
7935 object, or -1 if it is variable sized. The second argument is a pointer to
7936 the object.</p>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7937
7938<h5>Semantics:</h5>
7939<p>This intrinsic indicates that after this point in the code, the value of the
7940 memory pointed to by <tt>ptr</tt> is dead. This means that it is known to
7941 never be used and has an undefined value. Any stores into the memory object
7942 following this intrinsic may be removed as dead.
7943
7944</div>
7945
7946<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7947<h4>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7948 <a name="int_invariant_start">'<tt>llvm.invariant.start</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7949</h4>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7950
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7951<div>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7952
7953<h5>Syntax:</h5>
7954<pre>
Nick Lewycky29b6cb42010-11-30 04:13:41 +0000[diff] [blame]7955 declare {}* @llvm.invariant.start(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7956</pre>
7957
7958<h5>Overview:</h5>
7959<p>The '<tt>llvm.invariant.start</tt>' intrinsic specifies that the contents of
7960 a memory object will not change.</p>
7961
7962<h5>Arguments:</h5>
Nick Lewycky321333e2009-10-13 07:57:33 +0000[diff] [blame]7963<p>The first argument is a constant integer representing the size of the
7964 object, or -1 if it is variable sized. The second argument is a pointer to
7965 the object.</p>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7966
7967<h5>Semantics:</h5>
7968<p>This intrinsic indicates that until an <tt>llvm.invariant.end</tt> that uses
7969 the return value, the referenced memory location is constant and
7970 unchanging.</p>
7971
7972</div>
7973
7974<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7975<h4>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7976 <a name="int_invariant_end">'<tt>llvm.invariant.end</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7977</h4>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7978
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7979<div>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7980
7981<h5>Syntax:</h5>
7982<pre>
7983 declare void @llvm.invariant.end({}* &lt;start&gt;, i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7984</pre>
7985
7986<h5>Overview:</h5>
7987<p>The '<tt>llvm.invariant.end</tt>' intrinsic specifies that the contents of
7988 a memory object are mutable.</p>
7989
7990<h5>Arguments:</h5>
7991<p>The first argument is the matching <tt>llvm.invariant.start</tt> intrinsic.
Nick Lewycky321333e2009-10-13 07:57:33 +0000[diff] [blame]7992 The second argument is a constant integer representing the size of the
7993 object, or -1 if it is variable sized and the third argument is a pointer
7994 to the object.</p>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7995
7996<h5>Semantics:</h5>
7997<p>This intrinsic indicates that the memory is mutable again.</p>
7998
7999</div>
8000
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8001</div>
8002
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]8003<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8004<h3>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]8005 <a name="int_general">General Intrinsics</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8006</h3>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]8007
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8008<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8009
8010<p>This class of intrinsics is designed to be generic and has no specific
8011 purpose.</p>
8012
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]8013<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8014<h4>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]8015 <a name="int_var_annotation">'<tt>llvm.var.annotation</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8016</h4>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]8017
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8018<div>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]8019
8020<h5>Syntax:</h5>
8021<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]8022 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]8023</pre>
8024
8025<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8026<p>The '<tt>llvm.var.annotation</tt>' intrinsic.</p>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]8027
8028<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8029<p>The first argument is a pointer to a value, the second is a pointer to a
8030 global string, the third is a pointer to a global string which is the source
8031 file name, and the last argument is the line number.</p>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]8032
8033<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8034<p>This intrinsic allows annotation of local variables with arbitrary strings.
8035 This can be useful for special purpose optimizations that want to look for
John Criswelle865c032011-08-19 16:57:55 +0000[diff] [blame]8036 these annotations. These have no other defined use; they are ignored by code
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8037 generation and optimization.</p>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]8038
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]8039</div>
8040
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]8041<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8042<h4>
Tanya Lattnere1a8da02007-09-21 23:57:59 +0000[diff] [blame]8043 <a name="int_annotation">'<tt>llvm.annotation.*</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8044</h4>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]8045
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8046<div>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]8047
8048<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8049<p>This is an overloaded intrinsic. You can use '<tt>llvm.annotation</tt>' on
8050 any integer bit width.</p>
8051
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]8052<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]8053 declare i8 @llvm.annotation.i8(i8 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
8054 declare i16 @llvm.annotation.i16(i16 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
8055 declare i32 @llvm.annotation.i32(i32 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
8056 declare i64 @llvm.annotation.i64(i64 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
8057 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]8058</pre>
8059
8060<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8061<p>The '<tt>llvm.annotation</tt>' intrinsic.</p>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]8062
8063<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8064<p>The first argument is an integer value (result of some expression), the
8065 second is a pointer to a global string, the third is a pointer to a global
8066 string which is the source file name, and the last argument is the line
8067 number. It returns the value of the first argument.</p>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]8068
8069<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8070<p>This intrinsic allows annotations to be put on arbitrary expressions with
8071 arbitrary strings. This can be useful for special purpose optimizations that
John Criswelle865c032011-08-19 16:57:55 +0000[diff] [blame]8072 want to look for these annotations. These have no other defined use; they
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8073 are ignored by code generation and optimization.</p>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]8074
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]8075</div>
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]8076
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]8077<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8078<h4>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]8079 <a name="int_trap">'<tt>llvm.trap</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8080</h4>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]8081
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8082<div>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]8083
8084<h5>Syntax:</h5>
8085<pre>
8086 declare void @llvm.trap()
8087</pre>
8088
8089<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8090<p>The '<tt>llvm.trap</tt>' intrinsic.</p>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]8091
8092<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8093<p>None.</p>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]8094
8095<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8096<p>This intrinsics is lowered to the target dependent trap instruction. If the
8097 target does not have a trap instruction, this intrinsic will be lowered to
8098 the call of the <tt>abort()</tt> function.</p>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]8099
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]8100</div>
8101
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]8102<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8103<h4>
Misha Brukmandccb0252008-11-22 23:55:29 +0000[diff] [blame]8104 <a name="int_stackprotector">'<tt>llvm.stackprotector</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8105</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8106
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8107<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8108
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]8109<h5>Syntax:</h5>
8110<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]8111 declare void @llvm.stackprotector(i8* &lt;guard&gt;, i8** &lt;slot&gt;)
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]8112</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8113
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]8114<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8115<p>The <tt>llvm.stackprotector</tt> intrinsic takes the <tt>guard</tt> and
8116 stores it onto the stack at <tt>slot</tt>. The stack slot is adjusted to
8117 ensure that it is placed on the stack before local variables.</p>
8118
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]8119<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8120<p>The <tt>llvm.stackprotector</tt> intrinsic requires two pointer
8121 arguments. The first argument is the value loaded from the stack
8122 guard <tt>@__stack_chk_guard</tt>. The second variable is an <tt>alloca</tt>
8123 that has enough space to hold the value of the guard.</p>
8124
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]8125<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8126<p>This intrinsic causes the prologue/epilogue inserter to force the position of
8127 the <tt>AllocaInst</tt> stack slot to be before local variables on the
8128 stack. This is to ensure that if a local variable on the stack is
8129 overwritten, it will destroy the value of the guard. When the function exits,
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]8130 the guard on the stack is checked against the original guard. If they are
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8131 different, then the program aborts by calling the <tt>__stack_chk_fail()</tt>
8132 function.</p>
8133
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]8134</div>
8135
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]8136<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8137<h4>
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]8138 <a name="int_objectsize">'<tt>llvm.objectsize</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8139</h4>
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]8140
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8141<div>
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]8142
8143<h5>Syntax:</h5>
8144<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]8145 declare i32 @llvm.objectsize.i32(i8* &lt;object&gt;, i1 &lt;type&gt;)
8146 declare i64 @llvm.objectsize.i64(i8* &lt;object&gt;, i1 &lt;type&gt;)
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]8147</pre>
8148
8149<h5>Overview:</h5>
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]8150<p>The <tt>llvm.objectsize</tt> intrinsic is designed to provide information to
8151 the optimizers to determine at compile time whether a) an operation (like
8152 memcpy) will overflow a buffer that corresponds to an object, or b) that a
8153 runtime check for overflow isn't necessary. An object in this context means
8154 an allocation of a specific class, structure, array, or other object.</p>
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]8155
8156<h5>Arguments:</h5>
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]8157<p>The <tt>llvm.objectsize</tt> intrinsic takes two arguments. The first
Eric Christopher8295a0a2009-12-23 00:29:49 +0000[diff] [blame]8158 argument is a pointer to or into the <tt>object</tt>. The second argument
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]8159 is a boolean 0 or 1. This argument determines whether you want the
8160 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]8161 1, variables are not allowed.</p>
8162
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]8163<h5>Semantics:</h5>
8164<p>The <tt>llvm.objectsize</tt> intrinsic is lowered to either a constant
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]8165 representing the size of the object concerned, or <tt>i32/i64 -1 or 0</tt>,
8166 depending on the <tt>type</tt> argument, if the size cannot be determined at
8167 compile time.</p>
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]8168
8169</div>
8170
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8171</div>
8172
8173</div>
8174
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]8175<!-- *********************************************************************** -->
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]8176<hr>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]8177<address>
8178 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
Misha Brukman44408702008-12-11 17:34:48 +0000[diff] [blame]8179 src="http://jigsaw.w3.org/css-validator/images/vcss-blue" alt="Valid CSS"></a>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]8180 <a href="http://validator.w3.org/check/referer"><img
Misha Brukman44408702008-12-11 17:34:48 +0000[diff] [blame]8181 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]8182
8183 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
NAKAMURA Takumib9a33632011-04-09 02:13:37 +0000[diff] [blame]8184 <a href="http://llvm.org/">The LLVM Compiler Infrastructure</a><br>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]8185 Last modified: $Date$
8186</address>
Chris Lattnerc7d3ab32008-01-04 04:33:49 +0000[diff] [blame]8187
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]8188</body>
8189</html>