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gerrit-public.fairphone.software / platform / external / llvm / 32a43cc0fc3cd42702d7859eaa58dd42f561a54d / . / docs / LangRef.html
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5 <title>LLVM Assembly Language Reference Manual</title>
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7 <meta name="author" content="Chris Lattner">
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]8 <meta name="description"
Reid Spencer3921c742004-08-26 20:44:00 +0000[diff] [blame]9 content="LLVM Assembly Language Reference Manual.">
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]10 <link rel="stylesheet" href="llvm.css" type="text/css">
11</head>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]12
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]13<body>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]14
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]15<h1>LLVM Language Reference Manual</h1>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]16<ol>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]17 <li><a href="#abstract">Abstract</a></li>
18 <li><a href="#introduction">Introduction</a></li>
19 <li><a href="#identifiers">Identifiers</a></li>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]20 <li><a href="#highlevel">High Level Structure</a>
21 <ol>
22 <li><a href="#modulestructure">Module Structure</a></li>
Bill Wendling3d10a5a2009-07-20 01:03:30 +0000[diff] [blame]23 <li><a href="#linkage">Linkage Types</a>
24 <ol>
Bill Wendling987e7eb2009-07-20 02:41:50 +0000[diff] [blame]25 <li><a href="#linkage_private">'<tt>private</tt>' Linkage</a></li>
26 <li><a href="#linkage_linker_private">'<tt>linker_private</tt>' Linkage</a></li>
Bill Wendling5e721d72010-07-01 21:55:59 +0000[diff] [blame]27 <li><a href="#linkage_linker_private_weak">'<tt>linker_private_weak</tt>' Linkage</a></li>
Bill Wendling55ae5152010-08-20 22:05:50 +0000[diff] [blame]28 <li><a href="#linkage_linker_private_weak_def_auto">'<tt>linker_private_weak_def_auto</tt>' Linkage</a></li>
Bill Wendling987e7eb2009-07-20 02:41:50 +0000[diff] [blame]29 <li><a href="#linkage_internal">'<tt>internal</tt>' Linkage</a></li>
30 <li><a href="#linkage_available_externally">'<tt>available_externally</tt>' Linkage</a></li>
31 <li><a href="#linkage_linkonce">'<tt>linkonce</tt>' Linkage</a></li>
32 <li><a href="#linkage_common">'<tt>common</tt>' Linkage</a></li>
33 <li><a href="#linkage_weak">'<tt>weak</tt>' Linkage</a></li>
34 <li><a href="#linkage_appending">'<tt>appending</tt>' Linkage</a></li>
35 <li><a href="#linkage_externweak">'<tt>extern_weak</tt>' Linkage</a></li>
Chris Lattner5a2d8752009-10-10 18:26:06 +0000[diff] [blame]36 <li><a href="#linkage_linkonce_odr">'<tt>linkonce_odr</tt>' Linkage</a></li>
Bill Wendling987e7eb2009-07-20 02:41:50 +0000[diff] [blame]37 <li><a href="#linkage_weak">'<tt>weak_odr</tt>' Linkage</a></li>
Bill Wendlingf7f06102011-10-11 06:41:28 +0000[diff] [blame]38 <li><a href="#linkage_external">'<tt>external</tt>' Linkage</a></li>
Bill Wendling987e7eb2009-07-20 02:41:50 +0000[diff] [blame]39 <li><a href="#linkage_dllimport">'<tt>dllimport</tt>' Linkage</a></li>
40 <li><a href="#linkage_dllexport">'<tt>dllexport</tt>' Linkage</a></li>
Bill Wendling3d10a5a2009-07-20 01:03:30 +0000[diff] [blame]41 </ol>
42 </li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]43 <li><a href="#callingconv">Calling Conventions</a></li>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]44 <li><a href="#namedtypes">Named Types</a></li>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]45 <li><a href="#globalvars">Global Variables</a></li>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]46 <li><a href="#functionstructure">Functions</a></li>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]47 <li><a href="#aliasstructure">Aliases</a></li>
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]48 <li><a href="#namedmetadatastructure">Named Metadata</a></li>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]49 <li><a href="#paramattrs">Parameter Attributes</a></li>
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]50 <li><a href="#fnattrs">Function Attributes</a></li>
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]51 <li><a href="#gc">Garbage Collector Names</a></li>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]52 <li><a href="#moduleasm">Module-Level Inline Assembly</a></li>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]53 <li><a href="#datalayout">Data Layout</a></li>
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]54 <li><a href="#pointeraliasing">Pointer Aliasing Rules</a></li>
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]55 <li><a href="#volatile">Volatile Memory Accesses</a></li>
Eli Friedman5b60e1b2011-07-20 21:35:53 +0000[diff] [blame]56 <li><a href="#memmodel">Memory Model for Concurrent Operations</a></li>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]57 <li><a href="#ordering">Atomic Memory Ordering Constraints</a></li>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]58 </ol>
59 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]60 <li><a href="#typesystem">Type System</a>
61 <ol>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]62 <li><a href="#t_classifications">Type Classifications</a></li>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]63 <li><a href="#t_primitive">Primitive Types</a>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]64 <ol>
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]65 <li><a href="#t_integer">Integer Type</a></li>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]66 <li><a href="#t_floating">Floating Point Types</a></li>
Dale Johannesen21fe99b2010-10-01 00:48:59 +0000[diff] [blame]67 <li><a href="#t_x86mmx">X86mmx Type</a></li>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]68 <li><a href="#t_void">Void Type</a></li>
69 <li><a href="#t_label">Label Type</a></li>
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]70 <li><a href="#t_metadata">Metadata Type</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]71 </ol>
72 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]73 <li><a href="#t_derived">Derived Types</a>
74 <ol>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]75 <li><a href="#t_aggregate">Aggregate Types</a>
76 <ol>
77 <li><a href="#t_array">Array Type</a></li>
78 <li><a href="#t_struct">Structure Type</a></li>
Chris Lattner628ed392011-07-23 19:59:08 +0000[diff] [blame]79 <li><a href="#t_opaque">Opaque Structure Types</a></li>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]80 <li><a href="#t_vector">Vector Type</a></li>
81 </ol>
82 </li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]83 <li><a href="#t_function">Function Type</a></li>
84 <li><a href="#t_pointer">Pointer Type</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]85 </ol>
86 </li>
87 </ol>
88 </li>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]89 <li><a href="#constants">Constants</a>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]90 <ol>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]91 <li><a href="#simpleconstants">Simple Constants</a></li>
Chris Lattner70882792009-02-28 18:32:25 +0000[diff] [blame]92 <li><a href="#complexconstants">Complex Constants</a></li>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]93 <li><a href="#globalconstants">Global Variable and Function Addresses</a></li>
94 <li><a href="#undefvalues">Undefined Values</a></li>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]95 <li><a href="#trapvalues">Trap Values</a></li>
Chris Lattnerf9d078e2009-10-27 21:19:13 +0000[diff] [blame]96 <li><a href="#blockaddress">Addresses of Basic Blocks</a></li>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]97 <li><a href="#constantexprs">Constant Expressions</a></li>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]98 </ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]99 </li>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]100 <li><a href="#othervalues">Other Values</a>
101 <ol>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]102 <li><a href="#inlineasm">Inline Assembler Expressions</a></li>
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]103 <li><a href="#metadata">Metadata Nodes and Metadata Strings</a></li>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]104 </ol>
105 </li>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]106 <li><a href="#intrinsic_globals">Intrinsic Global Variables</a>
107 <ol>
108 <li><a href="#intg_used">The '<tt>llvm.used</tt>' Global Variable</a></li>
Chris Lattner401e10c2009-07-20 06:14:25 +0000[diff] [blame]109 <li><a href="#intg_compiler_used">The '<tt>llvm.compiler.used</tt>'
110 Global Variable</a></li>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]111 <li><a href="#intg_global_ctors">The '<tt>llvm.global_ctors</tt>'
112 Global Variable</a></li>
113 <li><a href="#intg_global_dtors">The '<tt>llvm.global_dtors</tt>'
114 Global Variable</a></li>
115 </ol>
116 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]117 <li><a href="#instref">Instruction Reference</a>
118 <ol>
119 <li><a href="#terminators">Terminator Instructions</a>
120 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]121 <li><a href="#i_ret">'<tt>ret</tt>' Instruction</a></li>
122 <li><a href="#i_br">'<tt>br</tt>' Instruction</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]123 <li><a href="#i_switch">'<tt>switch</tt>' Instruction</a></li>
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]124 <li><a href="#i_indirectbr">'<tt>indirectbr</tt>' Instruction</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]125 <li><a href="#i_invoke">'<tt>invoke</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]126 <li><a href="#i_unwind">'<tt>unwind</tt>' Instruction</a></li>
Bill Wendlingdccc03b2011-07-31 06:30:59 +0000[diff] [blame]127 <li><a href="#i_resume">'<tt>resume</tt>' Instruction</a></li>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]128 <li><a href="#i_unreachable">'<tt>unreachable</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]129 </ol>
130 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]131 <li><a href="#binaryops">Binary Operations</a>
132 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]133 <li><a href="#i_add">'<tt>add</tt>' Instruction</a></li>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]134 <li><a href="#i_fadd">'<tt>fadd</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]135 <li><a href="#i_sub">'<tt>sub</tt>' Instruction</a></li>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]136 <li><a href="#i_fsub">'<tt>fsub</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]137 <li><a href="#i_mul">'<tt>mul</tt>' Instruction</a></li>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]138 <li><a href="#i_fmul">'<tt>fmul</tt>' Instruction</a></li>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]139 <li><a href="#i_udiv">'<tt>udiv</tt>' Instruction</a></li>
140 <li><a href="#i_sdiv">'<tt>sdiv</tt>' Instruction</a></li>
141 <li><a href="#i_fdiv">'<tt>fdiv</tt>' Instruction</a></li>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]142 <li><a href="#i_urem">'<tt>urem</tt>' Instruction</a></li>
143 <li><a href="#i_srem">'<tt>srem</tt>' Instruction</a></li>
144 <li><a href="#i_frem">'<tt>frem</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]145 </ol>
146 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]147 <li><a href="#bitwiseops">Bitwise Binary Operations</a>
148 <ol>
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]149 <li><a href="#i_shl">'<tt>shl</tt>' Instruction</a></li>
150 <li><a href="#i_lshr">'<tt>lshr</tt>' Instruction</a></li>
151 <li><a href="#i_ashr">'<tt>ashr</tt>' Instruction</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]152 <li><a href="#i_and">'<tt>and</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]153 <li><a href="#i_or">'<tt>or</tt>' Instruction</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]154 <li><a href="#i_xor">'<tt>xor</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]155 </ol>
156 </li>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]157 <li><a href="#vectorops">Vector Operations</a>
158 <ol>
159 <li><a href="#i_extractelement">'<tt>extractelement</tt>' Instruction</a></li>
160 <li><a href="#i_insertelement">'<tt>insertelement</tt>' Instruction</a></li>
161 <li><a href="#i_shufflevector">'<tt>shufflevector</tt>' Instruction</a></li>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]162 </ol>
163 </li>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]164 <li><a href="#aggregateops">Aggregate Operations</a>
165 <ol>
166 <li><a href="#i_extractvalue">'<tt>extractvalue</tt>' Instruction</a></li>
167 <li><a href="#i_insertvalue">'<tt>insertvalue</tt>' Instruction</a></li>
168 </ol>
169 </li>
Chris Lattner884a9702006-08-15 00:45:58 +0000[diff] [blame]170 <li><a href="#memoryops">Memory Access and Addressing Operations</a>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]171 <ol>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]172 <li><a href="#i_alloca">'<tt>alloca</tt>' Instruction</a></li>
173 <li><a href="#i_load">'<tt>load</tt>' Instruction</a></li>
174 <li><a href="#i_store">'<tt>store</tt>' Instruction</a></li>
175 <li><a href="#i_fence">'<tt>fence</tt>' Instruction</a></li>
176 <li><a href="#i_cmpxchg">'<tt>cmpxchg</tt>' Instruction</a></li>
177 <li><a href="#i_atomicrmw">'<tt>atomicrmw</tt>' Instruction</a></li>
Robert Bocchino7b81c752006-02-17 21:18:08 +0000[diff] [blame]178 <li><a href="#i_getelementptr">'<tt>getelementptr</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]179 </ol>
180 </li>
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]181 <li><a href="#convertops">Conversion Operations</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]182 <ol>
183 <li><a href="#i_trunc">'<tt>trunc .. to</tt>' Instruction</a></li>
184 <li><a href="#i_zext">'<tt>zext .. to</tt>' Instruction</a></li>
185 <li><a href="#i_sext">'<tt>sext .. to</tt>' Instruction</a></li>
186 <li><a href="#i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a></li>
187 <li><a href="#i_fpext">'<tt>fpext .. to</tt>' Instruction</a></li>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]188 <li><a href="#i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a></li>
189 <li><a href="#i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a></li>
190 <li><a href="#i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a></li>
191 <li><a href="#i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a></li>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]192 <li><a href="#i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a></li>
193 <li><a href="#i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a></li>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]194 <li><a href="#i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a></li>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]195 </ol>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]196 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]197 <li><a href="#otherops">Other Operations</a>
198 <ol>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]199 <li><a href="#i_icmp">'<tt>icmp</tt>' Instruction</a></li>
200 <li><a href="#i_fcmp">'<tt>fcmp</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]201 <li><a href="#i_phi">'<tt>phi</tt>' Instruction</a></li>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]202 <li><a href="#i_select">'<tt>select</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]203 <li><a href="#i_call">'<tt>call</tt>' Instruction</a></li>
Chris Lattnerfb6977d2006-01-13 23:26:01 +0000[diff] [blame]204 <li><a href="#i_va_arg">'<tt>va_arg</tt>' Instruction</a></li>
Bill Wendlingf78faf82011-08-02 21:52:38 +0000[diff] [blame]205 <li><a href="#i_landingpad">'<tt>landingpad</tt>' Instruction</a></li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]206 </ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]207 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]208 </ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]209 </li>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]210 <li><a href="#intrinsics">Intrinsic Functions</a>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]211 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]212 <li><a href="#int_varargs">Variable Argument Handling Intrinsics</a>
213 <ol>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]214 <li><a href="#int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a></li>
215 <li><a href="#int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a></li>
216 <li><a href="#int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]217 </ol>
218 </li>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]219 <li><a href="#int_gc">Accurate Garbage Collection Intrinsics</a>
220 <ol>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]221 <li><a href="#int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a></li>
222 <li><a href="#int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a></li>
223 <li><a href="#int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a></li>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]224 </ol>
225 </li>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]226 <li><a href="#int_codegen">Code Generator Intrinsics</a>
227 <ol>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]228 <li><a href="#int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a></li>
229 <li><a href="#int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a></li>
230 <li><a href="#int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a></li>
231 <li><a href="#int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a></li>
232 <li><a href="#int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a></li>
233 <li><a href="#int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a></li>
Dan Gohman31f1af12010-05-26 21:56:15 +0000[diff] [blame]234 <li><a href="#int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a></li>
John Criswell7123e272004-04-09 16:43:20 +0000[diff] [blame]235 </ol>
236 </li>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]237 <li><a href="#int_libc">Standard C Library Intrinsics</a>
238 <ol>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]239 <li><a href="#int_memcpy">'<tt>llvm.memcpy.*</tt>' Intrinsic</a></li>
240 <li><a href="#int_memmove">'<tt>llvm.memmove.*</tt>' Intrinsic</a></li>
241 <li><a href="#int_memset">'<tt>llvm.memset.*</tt>' Intrinsic</a></li>
242 <li><a href="#int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a></li>
243 <li><a href="#int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a></li>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]244 <li><a href="#int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a></li>
245 <li><a href="#int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a></li>
246 <li><a href="#int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a></li>
Dan Gohman08b280b2011-05-27 00:36:31 +0000[diff] [blame]247 <li><a href="#int_exp">'<tt>llvm.exp.*</tt>' Intrinsic</a></li>
248 <li><a href="#int_log">'<tt>llvm.log.*</tt>' Intrinsic</a></li>
Cameron Zwarich33390842011-07-08 21:39:21 +0000[diff] [blame]249 <li><a href="#int_fma">'<tt>llvm.fma.*</tt>' Intrinsic</a></li>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]250 </ol>
251 </li>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]252 <li><a href="#int_manip">Bit Manipulation Intrinsics</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]253 <ol>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]254 <li><a href="#int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a></li>
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]255 <li><a href="#int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic </a></li>
256 <li><a href="#int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic </a></li>
257 <li><a href="#int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic </a></li>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]258 </ol>
259 </li>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]260 <li><a href="#int_overflow">Arithmetic with Overflow Intrinsics</a>
261 <ol>
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]262 <li><a href="#int_sadd_overflow">'<tt>llvm.sadd.with.overflow.*</tt> Intrinsics</a></li>
263 <li><a href="#int_uadd_overflow">'<tt>llvm.uadd.with.overflow.*</tt> Intrinsics</a></li>
264 <li><a href="#int_ssub_overflow">'<tt>llvm.ssub.with.overflow.*</tt> Intrinsics</a></li>
265 <li><a href="#int_usub_overflow">'<tt>llvm.usub.with.overflow.*</tt> Intrinsics</a></li>
266 <li><a href="#int_smul_overflow">'<tt>llvm.smul.with.overflow.*</tt> Intrinsics</a></li>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]267 <li><a href="#int_umul_overflow">'<tt>llvm.umul.with.overflow.*</tt> Intrinsics</a></li>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]268 </ol>
269 </li>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]270 <li><a href="#int_fp16">Half Precision Floating Point Intrinsics</a>
271 <ol>
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]272 <li><a href="#int_convert_to_fp16">'<tt>llvm.convert.to.fp16</tt>' Intrinsic</a></li>
273 <li><a href="#int_convert_from_fp16">'<tt>llvm.convert.from.fp16</tt>' Intrinsic</a></li>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]274 </ol>
275 </li>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]276 <li><a href="#int_debugger">Debugger intrinsics</a></li>
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]277 <li><a href="#int_eh">Exception Handling intrinsics</a></li>
Duncan Sands4a544a72011-09-06 13:37:06 +0000[diff] [blame]278 <li><a href="#int_trampoline">Trampoline Intrinsics</a>
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]279 <ol>
280 <li><a href="#int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a></li>
Duncan Sands4a544a72011-09-06 13:37:06 +0000[diff] [blame]281 <li><a href="#int_at">'<tt>llvm.adjust.trampoline</tt>' Intrinsic</a></li>
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]282 </ol>
283 </li>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]284 <li><a href="#int_memorymarkers">Memory Use Markers</a>
285 <ol>
286 <li><a href="#int_lifetime_start"><tt>llvm.lifetime.start</tt></a></li>
287 <li><a href="#int_lifetime_end"><tt>llvm.lifetime.end</tt></a></li>
288 <li><a href="#int_invariant_start"><tt>llvm.invariant.start</tt></a></li>
289 <li><a href="#int_invariant_end"><tt>llvm.invariant.end</tt></a></li>
290 </ol>
291 </li>
Reid Spencer20677642007-07-20 19:59:11 +0000[diff] [blame]292 <li><a href="#int_general">General intrinsics</a>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]293 <ol>
Reid Spencer20677642007-07-20 19:59:11 +0000[diff] [blame]294 <li><a href="#int_var_annotation">
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]295 '<tt>llvm.var.annotation</tt>' Intrinsic</a></li>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]296 <li><a href="#int_annotation">
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]297 '<tt>llvm.annotation.*</tt>' Intrinsic</a></li>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]298 <li><a href="#int_trap">
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]299 '<tt>llvm.trap</tt>' Intrinsic</a></li>
300 <li><a href="#int_stackprotector">
301 '<tt>llvm.stackprotector</tt>' Intrinsic</a></li>
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]302 <li><a href="#int_objectsize">
303 '<tt>llvm.objectsize</tt>' Intrinsic</a></li>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]304 </ol>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]305 </li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]306 </ol>
307 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]308</ol>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]309
310<div class="doc_author">
311 <p>Written by <a href="mailto:sabre@nondot.org">Chris Lattner</a>
312 and <a href="mailto:vadve@cs.uiuc.edu">Vikram Adve</a></p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]313</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]314
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]315<!-- *********************************************************************** -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]316<h2><a name="abstract">Abstract</a></h2>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]317<!-- *********************************************************************** -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]318
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]319<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]320
321<p>This document is a reference manual for the LLVM assembly language. LLVM is
322 a Static Single Assignment (SSA) based representation that provides type
323 safety, low-level operations, flexibility, and the capability of representing
324 'all' high-level languages cleanly. It is the common code representation
325 used throughout all phases of the LLVM compilation strategy.</p>
326
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]327</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]328
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]329<!-- *********************************************************************** -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]330<h2><a name="introduction">Introduction</a></h2>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]331<!-- *********************************************************************** -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]332
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]333<div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]334
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]335<p>The LLVM code representation is designed to be used in three different forms:
336 as an in-memory compiler IR, as an on-disk bitcode representation (suitable
337 for fast loading by a Just-In-Time compiler), and as a human readable
338 assembly language representation. This allows LLVM to provide a powerful
339 intermediate representation for efficient compiler transformations and
340 analysis, while providing a natural means to debug and visualize the
341 transformations. The three different forms of LLVM are all equivalent. This
342 document describes the human readable representation and notation.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]343
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]344<p>The LLVM representation aims to be light-weight and low-level while being
345 expressive, typed, and extensible at the same time. It aims to be a
346 "universal IR" of sorts, by being at a low enough level that high-level ideas
347 may be cleanly mapped to it (similar to how microprocessors are "universal
348 IR's", allowing many source languages to be mapped to them). By providing
349 type information, LLVM can be used as the target of optimizations: for
350 example, through pointer analysis, it can be proven that a C automatic
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]351 variable is never accessed outside of the current function, allowing it to
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]352 be promoted to a simple SSA value instead of a memory location.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]353
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]354<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]355<h4>
356 <a name="wellformed">Well-Formedness</a>
357</h4>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]358
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]359<div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]360
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]361<p>It is important to note that this document describes 'well formed' LLVM
362 assembly language. There is a difference between what the parser accepts and
363 what is considered 'well formed'. For example, the following instruction is
364 syntactically okay, but not well formed:</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]365
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]366<pre class="doc_code">
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]367%x = <a href="#i_add">add</a> i32 1, %x
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]368</pre>
369
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]370<p>because the definition of <tt>%x</tt> does not dominate all of its uses. The
371 LLVM infrastructure provides a verification pass that may be used to verify
372 that an LLVM module is well formed. This pass is automatically run by the
373 parser after parsing input assembly and by the optimizer before it outputs
374 bitcode. The violations pointed out by the verifier pass indicate bugs in
375 transformation passes or input to the parser.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]376
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]377</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]378
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]379</div>
380
Chris Lattnercc689392007-10-03 17:34:29 +0000[diff] [blame]381<!-- Describe the typesetting conventions here. -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]382
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]383<!-- *********************************************************************** -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]384<h2><a name="identifiers">Identifiers</a></h2>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]385<!-- *********************************************************************** -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]386
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]387<div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]388
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]389<p>LLVM identifiers come in two basic types: global and local. Global
390 identifiers (functions, global variables) begin with the <tt>'@'</tt>
391 character. Local identifiers (register names, types) begin with
392 the <tt>'%'</tt> character. Additionally, there are three different formats
393 for identifiers, for different purposes:</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]394
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]395<ol>
Reid Spencer2c452282007-08-07 14:34:28 +0000[diff] [blame]396 <li>Named values are represented as a string of characters with their prefix.
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]397 For example, <tt>%foo</tt>, <tt>@DivisionByZero</tt>,
398 <tt>%a.really.long.identifier</tt>. The actual regular expression used is
399 '<tt>[%@][a-zA-Z$._][a-zA-Z$._0-9]*</tt>'. Identifiers which require
400 other characters in their names can be surrounded with quotes. Special
401 characters may be escaped using <tt>"\xx"</tt> where <tt>xx</tt> is the
402 ASCII code for the character in hexadecimal. In this way, any character
403 can be used in a name value, even quotes themselves.</li>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]404
Reid Spencer2c452282007-08-07 14:34:28 +0000[diff] [blame]405 <li>Unnamed values are represented as an unsigned numeric value with their
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]406 prefix. For example, <tt>%12</tt>, <tt>@2</tt>, <tt>%44</tt>.</li>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]407
Reid Spencercc16dc32004-12-09 18:02:53 +0000[diff] [blame]408 <li>Constants, which are described in a <a href="#constants">section about
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]409 constants</a>, below.</li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]410</ol>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]411
Reid Spencer2c452282007-08-07 14:34:28 +0000[diff] [blame]412<p>LLVM requires that values start with a prefix for two reasons: Compilers
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]413 don't need to worry about name clashes with reserved words, and the set of
414 reserved words may be expanded in the future without penalty. Additionally,
415 unnamed identifiers allow a compiler to quickly come up with a temporary
416 variable without having to avoid symbol table conflicts.</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]417
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]418<p>Reserved words in LLVM are very similar to reserved words in other
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]419 languages. There are keywords for different opcodes
420 ('<tt><a href="#i_add">add</a></tt>',
421 '<tt><a href="#i_bitcast">bitcast</a></tt>',
422 '<tt><a href="#i_ret">ret</a></tt>', etc...), for primitive type names
423 ('<tt><a href="#t_void">void</a></tt>',
424 '<tt><a href="#t_primitive">i32</a></tt>', etc...), and others. These
425 reserved words cannot conflict with variable names, because none of them
426 start with a prefix character (<tt>'%'</tt> or <tt>'@'</tt>).</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]427
428<p>Here is an example of LLVM code to multiply the integer variable
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]429 '<tt>%X</tt>' by 8:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]430
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]431<p>The easy way:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]432
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]433<pre class="doc_code">
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]434%result = <a href="#i_mul">mul</a> i32 %X, 8
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]435</pre>
436
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]437<p>After strength reduction:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]438
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]439<pre class="doc_code">
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]440%result = <a href="#i_shl">shl</a> i32 %X, i8 3
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]441</pre>
442
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]443<p>And the hard way:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]444
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]445<pre class="doc_code">
Gabor Greifec58f752009-10-28 13:05:07 +0000[diff] [blame]446%0 = <a href="#i_add">add</a> i32 %X, %X <i>; yields {i32}:%0</i>
447%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]448%result = <a href="#i_add">add</a> i32 %1, %1
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]449</pre>
450
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]451<p>This last way of multiplying <tt>%X</tt> by 8 illustrates several important
452 lexical features of LLVM:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]453
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]454<ol>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]455 <li>Comments are delimited with a '<tt>;</tt>' and go until the end of
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]456 line.</li>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]457
458 <li>Unnamed temporaries are created when the result of a computation is not
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]459 assigned to a named value.</li>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]460
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]461 <li>Unnamed temporaries are numbered sequentially</li>
462</ol>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]463
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]464<p>It also shows a convention that we follow in this document. When
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]465 demonstrating instructions, we will follow an instruction with a comment that
466 defines the type and name of value produced. Comments are shown in italic
467 text.</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]468
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]469</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]470
471<!-- *********************************************************************** -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]472<h2><a name="highlevel">High Level Structure</a></h2>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]473<!-- *********************************************************************** -->
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]474<div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]475<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]476<h3>
477 <a name="modulestructure">Module Structure</a>
478</h3>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]479
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]480<div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]481
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]482<p>LLVM programs are composed of "Module"s, each of which is a translation unit
483 of the input programs. Each module consists of functions, global variables,
484 and symbol table entries. Modules may be combined together with the LLVM
485 linker, which merges function (and global variable) definitions, resolves
486 forward declarations, and merges symbol table entries. Here is an example of
487 the "hello world" module:</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]488
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]489<pre class="doc_code">
Chris Lattner63e4ccb2010-08-17 17:13:42 +0000[diff] [blame]490<i>; Declare the string constant as a global constant.</i>&nbsp;
Nick Lewyckydb9cd762011-01-29 01:09:53 +0000[diff] [blame]491<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]492
Chris Lattner63e4ccb2010-08-17 17:13:42 +0000[diff] [blame]493<i>; External declaration of the puts function</i>&nbsp;
494<a href="#functionstructure">declare</a> i32 @puts(i8*) <i>; i32 (i8*)* </i>&nbsp;
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]495
496<i>; Definition of main function</i>
Chris Lattner63e4ccb2010-08-17 17:13:42 +0000[diff] [blame]497define i32 @main() { <i>; i32()* </i>&nbsp;
498 <i>; Convert [13 x i8]* to i8 *...</i>&nbsp;
499 %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]500
Chris Lattner63e4ccb2010-08-17 17:13:42 +0000[diff] [blame]501 <i>; Call puts function to write out the string to stdout.</i>&nbsp;
502 <a href="#i_call">call</a> i32 @puts(i8* %cast210) <i>; i32</i>&nbsp;
503 <a href="#i_ret">ret</a> i32 0&nbsp;
504}
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]505
506<i>; Named metadata</i>
507!1 = metadata !{i32 41}
508!foo = !{!1, null}
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]509</pre>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]510
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]511<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]512 "<tt>.LC0</tt>", an external declaration of the "<tt>puts</tt>" function,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]513 a <a href="#functionstructure">function definition</a> for
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]514 "<tt>main</tt>" and <a href="#namedmetadatastructure">named metadata</a>
515 "<tt>foo"</tt>.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]516
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]517<p>In general, a module is made up of a list of global values, where both
518 functions and global variables are global values. Global values are
519 represented by a pointer to a memory location (in this case, a pointer to an
520 array of char, and a pointer to a function), and have one of the
521 following <a href="#linkage">linkage types</a>.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]522
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]523</div>
524
525<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]526<h3>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]527 <a name="linkage">Linkage Types</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]528</h3>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]529
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]530<div>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]531
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]532<p>All Global Variables and Functions have one of the following types of
533 linkage:</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]534
535<dl>
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]536 <dt><tt><b><a name="linkage_private">private</a></b></tt></dt>
Bill Wendling5e721d72010-07-01 21:55:59 +0000[diff] [blame]537 <dd>Global values with "<tt>private</tt>" linkage are only directly accessible
538 by objects in the current module. In particular, linking code into a
539 module with an private global value may cause the private to be renamed as
540 necessary to avoid collisions. Because the symbol is private to the
541 module, all references can be updated. This doesn't show up in any symbol
542 table in the object file.</dd>
Rafael Espindolabb46f522009-01-15 20:18:42 +0000[diff] [blame]543
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]544 <dt><tt><b><a name="linkage_linker_private">linker_private</a></b></tt></dt>
Bill Wendling5e721d72010-07-01 21:55:59 +0000[diff] [blame]545 <dd>Similar to <tt>private</tt>, but the symbol is passed through the
546 assembler and evaluated by the linker. Unlike normal strong symbols, they
547 are removed by the linker from the final linked image (executable or
548 dynamic library).</dd>
549
550 <dt><tt><b><a name="linkage_linker_private_weak">linker_private_weak</a></b></tt></dt>
551 <dd>Similar to "<tt>linker_private</tt>", but the symbol is weak. Note that
552 <tt>linker_private_weak</tt> symbols are subject to coalescing by the
553 linker. The symbols are removed by the linker from the final linked image
554 (executable or dynamic library).</dd>
Bill Wendling3d10a5a2009-07-20 01:03:30 +0000[diff] [blame]555
Bill Wendling55ae5152010-08-20 22:05:50 +0000[diff] [blame]556 <dt><tt><b><a name="linkage_linker_private_weak_def_auto">linker_private_weak_def_auto</a></b></tt></dt>
557 <dd>Similar to "<tt>linker_private_weak</tt>", but it's known that the address
558 of the object is not taken. For instance, functions that had an inline
559 definition, but the compiler decided not to inline it. Note,
560 unlike <tt>linker_private</tt> and <tt>linker_private_weak</tt>,
561 <tt>linker_private_weak_def_auto</tt> may have only <tt>default</tt>
562 visibility. The symbols are removed by the linker from the final linked
563 image (executable or dynamic library).</dd>
564
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]565 <dt><tt><b><a name="linkage_internal">internal</a></b></tt></dt>
Bill Wendling07d31772010-06-29 22:34:52 +0000[diff] [blame]566 <dd>Similar to private, but the value shows as a local symbol
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]567 (<tt>STB_LOCAL</tt> in the case of ELF) in the object file. This
568 corresponds to the notion of the '<tt>static</tt>' keyword in C.</dd>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]569
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]570 <dt><tt><b><a name="linkage_available_externally">available_externally</a></b></tt></dt>
Chris Lattner266c7bb2009-04-13 05:44:34 +0000[diff] [blame]571 <dd>Globals with "<tt>available_externally</tt>" linkage are never emitted
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]572 into the object file corresponding to the LLVM module. They exist to
573 allow inlining and other optimizations to take place given knowledge of
574 the definition of the global, which is known to be somewhere outside the
575 module. Globals with <tt>available_externally</tt> linkage are allowed to
576 be discarded at will, and are otherwise the same as <tt>linkonce_odr</tt>.
577 This linkage type is only allowed on definitions, not declarations.</dd>
Chris Lattner266c7bb2009-04-13 05:44:34 +0000[diff] [blame]578
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]579 <dt><tt><b><a name="linkage_linkonce">linkonce</a></b></tt></dt>
Chris Lattner4887bd82007-01-14 06:51:48 +0000[diff] [blame]580 <dd>Globals with "<tt>linkonce</tt>" linkage are merged with other globals of
Chris Lattner873187c2010-01-09 19:15:14 +0000[diff] [blame]581 the same name when linkage occurs. This can be used to implement
582 some forms of inline functions, templates, or other code which must be
583 generated in each translation unit that uses it, but where the body may
584 be overridden with a more definitive definition later. Unreferenced
585 <tt>linkonce</tt> globals are allowed to be discarded. Note that
586 <tt>linkonce</tt> linkage does not actually allow the optimizer to
587 inline the body of this function into callers because it doesn't know if
588 this definition of the function is the definitive definition within the
589 program or whether it will be overridden by a stronger definition.
590 To enable inlining and other optimizations, use "<tt>linkonce_odr</tt>"
591 linkage.</dd>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]592
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]593 <dt><tt><b><a name="linkage_weak">weak</a></b></tt></dt>
Chris Lattner26d054d2009-08-05 05:21:07 +0000[diff] [blame]594 <dd>"<tt>weak</tt>" linkage has the same merging semantics as
595 <tt>linkonce</tt> linkage, except that unreferenced globals with
596 <tt>weak</tt> linkage may not be discarded. This is used for globals that
597 are declared "weak" in C source code.</dd>
598
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]599 <dt><tt><b><a name="linkage_common">common</a></b></tt></dt>
Chris Lattner26d054d2009-08-05 05:21:07 +0000[diff] [blame]600 <dd>"<tt>common</tt>" linkage is most similar to "<tt>weak</tt>" linkage, but
601 they are used for tentative definitions in C, such as "<tt>int X;</tt>" at
602 global scope.
603 Symbols with "<tt>common</tt>" linkage are merged in the same way as
604 <tt>weak symbols</tt>, and they may not be deleted if unreferenced.
Chris Lattnercd81f5d2009-08-05 05:41:44 +0000[diff] [blame]605 <tt>common</tt> symbols may not have an explicit section,
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]606 must have a zero initializer, and may not be marked '<a
Chris Lattnercd81f5d2009-08-05 05:41:44 +0000[diff] [blame]607 href="#globalvars"><tt>constant</tt></a>'. Functions and aliases may not
608 have common linkage.</dd>
Chris Lattner26d054d2009-08-05 05:21:07 +0000[diff] [blame]609
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]610
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]611 <dt><tt><b><a name="linkage_appending">appending</a></b></tt></dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]612 <dd>"<tt>appending</tt>" linkage may only be applied to global variables of
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]613 pointer to array type. When two global variables with appending linkage
614 are linked together, the two global arrays are appended together. This is
615 the LLVM, typesafe, equivalent of having the system linker append together
616 "sections" with identical names when .o files are linked.</dd>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]617
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]618 <dt><tt><b><a name="linkage_externweak">extern_weak</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]619 <dd>The semantics of this linkage follow the ELF object file model: the symbol
620 is weak until linked, if not linked, the symbol becomes null instead of
621 being an undefined reference.</dd>
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]622
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]623 <dt><tt><b><a name="linkage_linkonce_odr">linkonce_odr</a></b></tt></dt>
624 <dt><tt><b><a name="linkage_weak_odr">weak_odr</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]625 <dd>Some languages allow differing globals to be merged, such as two functions
626 with different semantics. Other languages, such as <tt>C++</tt>, ensure
Bill Wendling5e721d72010-07-01 21:55:59 +0000[diff] [blame]627 that only equivalent globals are ever merged (the "one definition rule"
628 &mdash; "ODR"). Such languages can use the <tt>linkonce_odr</tt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]629 and <tt>weak_odr</tt> linkage types to indicate that the global will only
630 be merged with equivalent globals. These linkage types are otherwise the
631 same as their non-<tt>odr</tt> versions.</dd>
Duncan Sands667d4b82009-03-07 15:45:40 +0000[diff] [blame]632
Bill Wendlingf7f06102011-10-11 06:41:28 +0000[diff] [blame]633 <dt><tt><b><a name="linkage_external">external</a></b></tt>:</dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]634 <dd>If none of the above identifiers are used, the global is externally
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]635 visible, meaning that it participates in linkage and can be used to
636 resolve external symbol references.</dd>
Reid Spencerc8910842007-04-11 23:49:50 +0000[diff] [blame]637</dl>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]638
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]639<p>The next two types of linkage are targeted for Microsoft Windows platform
640 only. They are designed to support importing (exporting) symbols from (to)
641 DLLs (Dynamic Link Libraries).</p>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]642
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]643<dl>
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]644 <dt><tt><b><a name="linkage_dllimport">dllimport</a></b></tt></dt>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]645 <dd>"<tt>dllimport</tt>" linkage causes the compiler to reference a function
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]646 or variable via a global pointer to a pointer that is set up by the DLL
647 exporting the symbol. On Microsoft Windows targets, the pointer name is
648 formed by combining <code>__imp_</code> and the function or variable
649 name.</dd>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]650
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]651 <dt><tt><b><a name="linkage_dllexport">dllexport</a></b></tt></dt>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]652 <dd>"<tt>dllexport</tt>" linkage causes the compiler to provide a global
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]653 pointer to a pointer in a DLL, so that it can be referenced with the
654 <tt>dllimport</tt> attribute. On Microsoft Windows targets, the pointer
655 name is formed by combining <code>__imp_</code> and the function or
656 variable name.</dd>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]657</dl>
658
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]659<p>For example, since the "<tt>.LC0</tt>" variable is defined to be internal, if
660 another module defined a "<tt>.LC0</tt>" variable and was linked with this
661 one, one of the two would be renamed, preventing a collision. Since
662 "<tt>main</tt>" and "<tt>puts</tt>" are external (i.e., lacking any linkage
663 declarations), they are accessible outside of the current module.</p>
664
665<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]666 other than <tt>external</tt>, <tt>dllimport</tt>
667 or <tt>extern_weak</tt>.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]668
Duncan Sands667d4b82009-03-07 15:45:40 +0000[diff] [blame]669<p>Aliases can have only <tt>external</tt>, <tt>internal</tt>, <tt>weak</tt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]670 or <tt>weak_odr</tt> linkages.</p>
671
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]672</div>
673
674<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]675<h3>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]676 <a name="callingconv">Calling Conventions</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]677</h3>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]678
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]679<div>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]680
681<p>LLVM <a href="#functionstructure">functions</a>, <a href="#i_call">calls</a>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]682 and <a href="#i_invoke">invokes</a> can all have an optional calling
683 convention specified for the call. The calling convention of any pair of
684 dynamic caller/callee must match, or the behavior of the program is
685 undefined. The following calling conventions are supported by LLVM, and more
686 may be added in the future:</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]687
688<dl>
689 <dt><b>"<tt>ccc</tt>" - The C calling convention</b>:</dt>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]690 <dd>This calling convention (the default if no other calling convention is
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]691 specified) matches the target C calling conventions. This calling
692 convention supports varargs function calls and tolerates some mismatch in
693 the declared prototype and implemented declaration of the function (as
694 does normal C).</dd>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]695
696 <dt><b>"<tt>fastcc</tt>" - The fast calling convention</b>:</dt>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]697 <dd>This calling convention attempts to make calls as fast as possible
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]698 (e.g. by passing things in registers). This calling convention allows the
699 target to use whatever tricks it wants to produce fast code for the
700 target, without having to conform to an externally specified ABI
Jeffrey Yasskin95fa80a2010-01-09 19:44:16 +0000[diff] [blame]701 (Application Binary Interface).
702 <a href="CodeGenerator.html#tailcallopt">Tail calls can only be optimized
Chris Lattner29689432010-03-11 00:22:57 +0000[diff] [blame]703 when this or the GHC convention is used.</a> This calling convention
704 does not support varargs and requires the prototype of all callees to
705 exactly match the prototype of the function definition.</dd>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]706
707 <dt><b>"<tt>coldcc</tt>" - The cold calling convention</b>:</dt>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]708 <dd>This calling convention attempts to make code in the caller as efficient
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]709 as possible under the assumption that the call is not commonly executed.
710 As such, these calls often preserve all registers so that the call does
711 not break any live ranges in the caller side. This calling convention
712 does not support varargs and requires the prototype of all callees to
713 exactly match the prototype of the function definition.</dd>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]714
Chris Lattner29689432010-03-11 00:22:57 +0000[diff] [blame]715 <dt><b>"<tt>cc <em>10</em></tt>" - GHC convention</b>:</dt>
716 <dd>This calling convention has been implemented specifically for use by the
717 <a href="http://www.haskell.org/ghc">Glasgow Haskell Compiler (GHC)</a>.
718 It passes everything in registers, going to extremes to achieve this by
719 disabling callee save registers. This calling convention should not be
720 used lightly but only for specific situations such as an alternative to
721 the <em>register pinning</em> performance technique often used when
722 implementing functional programming languages.At the moment only X86
723 supports this convention and it has the following limitations:
724 <ul>
725 <li>On <em>X86-32</em> only supports up to 4 bit type parameters. No
726 floating point types are supported.</li>
727 <li>On <em>X86-64</em> only supports up to 10 bit type parameters and
728 6 floating point parameters.</li>
729 </ul>
730 This calling convention supports
731 <a href="CodeGenerator.html#tailcallopt">tail call optimization</a> but
732 requires both the caller and callee are using it.
733 </dd>
734
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame]735 <dt><b>"<tt>cc &lt;<em>n</em>&gt;</tt>" - Numbered convention</b>:</dt>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]736 <dd>Any calling convention may be specified by number, allowing
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]737 target-specific calling conventions to be used. Target specific calling
738 conventions start at 64.</dd>
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame]739</dl>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]740
741<p>More calling conventions can be added/defined on an as-needed basis, to
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]742 support Pascal conventions or any other well-known target-independent
743 convention.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]744
745</div>
746
747<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]748<h3>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]749 <a name="visibility">Visibility Styles</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]750</h3>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]751
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]752<div>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]753
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]754<p>All Global Variables and Functions have one of the following visibility
755 styles:</p>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]756
757<dl>
758 <dt><b>"<tt>default</tt>" - Default style</b>:</dt>
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]759 <dd>On targets that use the ELF object file format, default visibility means
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]760 that the declaration is visible to other modules and, in shared libraries,
761 means that the declared entity may be overridden. On Darwin, default
762 visibility means that the declaration is visible to other modules. Default
763 visibility corresponds to "external linkage" in the language.</dd>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]764
765 <dt><b>"<tt>hidden</tt>" - Hidden style</b>:</dt>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]766 <dd>Two declarations of an object with hidden visibility refer to the same
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]767 object if they are in the same shared object. Usually, hidden visibility
768 indicates that the symbol will not be placed into the dynamic symbol
769 table, so no other module (executable or shared library) can reference it
770 directly.</dd>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]771
Anton Korobeynikov6f9896f2007-04-29 18:35:00 +0000[diff] [blame]772 <dt><b>"<tt>protected</tt>" - Protected style</b>:</dt>
Anton Korobeynikov6f9896f2007-04-29 18:35:00 +0000[diff] [blame]773 <dd>On ELF, protected visibility indicates that the symbol will be placed in
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]774 the dynamic symbol table, but that references within the defining module
775 will bind to the local symbol. That is, the symbol cannot be overridden by
776 another module.</dd>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]777</dl>
778
779</div>
780
781<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]782<h3>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]783 <a name="namedtypes">Named Types</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]784</h3>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]785
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]786<div>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]787
788<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]789 it easier to read the IR and make the IR more condensed (particularly when
790 recursive types are involved). An example of a name specification is:</p>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]791
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]792<pre class="doc_code">
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]793%mytype = type { %mytype*, i32 }
794</pre>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]795
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]796<p>You may give a name to any <a href="#typesystem">type</a> except
Chris Lattnerdc65f222010-08-17 23:26:04 +0000[diff] [blame]797 "<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]798 is expected with the syntax "%mytype".</p>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]799
800<p>Note that type names are aliases for the structural type that they indicate,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]801 and that you can therefore specify multiple names for the same type. This
802 often leads to confusing behavior when dumping out a .ll file. Since LLVM IR
803 uses structural typing, the name is not part of the type. When printing out
804 LLVM IR, the printer will pick <em>one name</em> to render all types of a
805 particular shape. This means that if you have code where two different
806 source types end up having the same LLVM type, that the dumper will sometimes
807 print the "wrong" or unexpected type. This is an important design point and
808 isn't going to change.</p>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]809
810</div>
811
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]812<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]813<h3>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]814 <a name="globalvars">Global Variables</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]815</h3>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]816
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]817<div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]818
Chris Lattner3689a342005-02-12 19:30:21 +0000[diff] [blame]819<p>Global variables define regions of memory allocated at compilation time
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]820 instead of run-time. Global variables may optionally be initialized, may
821 have an explicit section to be placed in, and may have an optional explicit
822 alignment specified. A variable may be defined as "thread_local", which
823 means that it will not be shared by threads (each thread will have a
824 separated copy of the variable). A variable may be defined as a global
825 "constant," which indicates that the contents of the variable
826 will <b>never</b> be modified (enabling better optimization, allowing the
827 global data to be placed in the read-only section of an executable, etc).
828 Note that variables that need runtime initialization cannot be marked
829 "constant" as there is a store to the variable.</p>
Chris Lattner3689a342005-02-12 19:30:21 +0000[diff] [blame]830
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]831<p>LLVM explicitly allows <em>declarations</em> of global variables to be marked
832 constant, even if the final definition of the global is not. This capability
833 can be used to enable slightly better optimization of the program, but
834 requires the language definition to guarantee that optimizations based on the
835 'constantness' are valid for the translation units that do not include the
836 definition.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]837
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]838<p>As SSA values, global variables define pointer values that are in scope
839 (i.e. they dominate) all basic blocks in the program. Global variables
840 always define a pointer to their "content" type because they describe a
841 region of memory, and all memory objects in LLVM are accessed through
842 pointers.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]843
Rafael Espindolabea46262011-01-08 16:42:36 +0000[diff] [blame]844<p>Global variables can be marked with <tt>unnamed_addr</tt> which indicates
845 that the address is not significant, only the content. Constants marked
Rafael Espindolaa5eaa862011-01-15 08:20:57 +0000[diff] [blame]846 like this can be merged with other constants if they have the same
847 initializer. Note that a constant with significant address <em>can</em>
848 be merged with a <tt>unnamed_addr</tt> constant, the result being a
849 constant whose address is significant.</p>
Rafael Espindolabea46262011-01-08 16:42:36 +0000[diff] [blame]850
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]851<p>A global variable may be declared to reside in a target-specific numbered
852 address space. For targets that support them, address spaces may affect how
853 optimizations are performed and/or what target instructions are used to
854 access the variable. The default address space is zero. The address space
855 qualifier must precede any other attributes.</p>
Christopher Lamb284d9922007-12-11 09:31:00 +0000[diff] [blame]856
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]857<p>LLVM allows an explicit section to be specified for globals. If the target
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]858 supports it, it will emit globals to the section specified.</p>
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]859
Chris Lattnerce99fa92010-04-28 00:13:42 +0000[diff] [blame]860<p>An explicit alignment may be specified for a global, which must be a power
861 of 2. If not present, or if the alignment is set to zero, the alignment of
862 the global is set by the target to whatever it feels convenient. If an
863 explicit alignment is specified, the global is forced to have exactly that
Chris Lattner2d4b8ee2010-04-28 00:31:12 +0000[diff] [blame]864 alignment. Targets and optimizers are not allowed to over-align the global
865 if the global has an assigned section. In this case, the extra alignment
866 could be observable: for example, code could assume that the globals are
867 densely packed in their section and try to iterate over them as an array,
868 alignment padding would break this iteration.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]869
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]870<p>For example, the following defines a global in a numbered address space with
871 an initializer, section, and alignment:</p>
Chris Lattner68027ea2007-01-14 00:27:09 +0000[diff] [blame]872
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]873<pre class="doc_code">
Dan Gohman398873c2009-01-11 00:40:00 +0000[diff] [blame]874@G = addrspace(5) constant float 1.0, section "foo", align 4
Chris Lattner68027ea2007-01-14 00:27:09 +0000[diff] [blame]875</pre>
876
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]877</div>
878
879
880<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]881<h3>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]882 <a name="functionstructure">Functions</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]883</h3>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]884
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]885<div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]886
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]887<p>LLVM function definitions consist of the "<tt>define</tt>" keyword, an
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]888 optional <a href="#linkage">linkage type</a>, an optional
889 <a href="#visibility">visibility style</a>, an optional
Rafael Espindolabea46262011-01-08 16:42:36 +0000[diff] [blame]890 <a href="#callingconv">calling convention</a>,
891 an optional <tt>unnamed_addr</tt> attribute, a return type, an optional
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]892 <a href="#paramattrs">parameter attribute</a> for the return type, a function
893 name, a (possibly empty) argument list (each with optional
894 <a href="#paramattrs">parameter attributes</a>), optional
895 <a href="#fnattrs">function attributes</a>, an optional section, an optional
896 alignment, an optional <a href="#gc">garbage collector name</a>, an opening
897 curly brace, a list of basic blocks, and a closing curly brace.</p>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]898
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]899<p>LLVM function declarations consist of the "<tt>declare</tt>" keyword, an
900 optional <a href="#linkage">linkage type</a>, an optional
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]901 <a href="#visibility">visibility style</a>, an optional
Rafael Espindolabea46262011-01-08 16:42:36 +0000[diff] [blame]902 <a href="#callingconv">calling convention</a>,
903 an optional <tt>unnamed_addr</tt> attribute, a return type, an optional
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]904 <a href="#paramattrs">parameter attribute</a> for the return type, a function
905 name, a possibly empty list of arguments, an optional alignment, and an
906 optional <a href="#gc">garbage collector name</a>.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]907
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]908<p>A function definition contains a list of basic blocks, forming the CFG
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]909 (Control Flow Graph) for the function. Each basic block may optionally start
910 with a label (giving the basic block a symbol table entry), contains a list
911 of instructions, and ends with a <a href="#terminators">terminator</a>
912 instruction (such as a branch or function return).</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]913
Chris Lattner4a3c9012007-06-08 16:52:14 +0000[diff] [blame]914<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]915 executed on entrance to the function, and it is not allowed to have
916 predecessor basic blocks (i.e. there can not be any branches to the entry
917 block of a function). Because the block can have no predecessors, it also
918 cannot have any <a href="#i_phi">PHI nodes</a>.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]919
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]920<p>LLVM allows an explicit section to be specified for functions. If the target
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]921 supports it, it will emit functions to the section specified.</p>
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]922
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]923<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]924 the alignment is set to zero, the alignment of the function is set by the
925 target to whatever it feels convenient. If an explicit alignment is
926 specified, the function is forced to have at least that much alignment. All
927 alignments must be a power of 2.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]928
Rafael Espindolabea46262011-01-08 16:42:36 +0000[diff] [blame]929<p>If the <tt>unnamed_addr</tt> attribute is given, the address is know to not
930 be significant and two identical functions can be merged</p>.
931
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]932<h5>Syntax:</h5>
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]933<pre class="doc_code">
Chris Lattner50ad45c2008-10-13 16:55:18 +0000[diff] [blame]934define [<a href="#linkage">linkage</a>] [<a href="#visibility">visibility</a>]
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]935 [<a href="#callingconv">cconv</a>] [<a href="#paramattrs">ret attrs</a>]
936 &lt;ResultType&gt; @&lt;FunctionName&gt; ([argument list])
937 [<a href="#fnattrs">fn Attrs</a>] [section "name"] [align N]
938 [<a href="#gc">gc</a>] { ... }
939</pre>
Devang Patel307e8ab2008-10-07 17:48:33 +0000[diff] [blame]940
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]941</div>
942
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]943<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]944<h3>
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]945 <a name="aliasstructure">Aliases</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]946</h3>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]947
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]948<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]949
950<p>Aliases act as "second name" for the aliasee value (which can be either
951 function, global variable, another alias or bitcast of global value). Aliases
952 may have an optional <a href="#linkage">linkage type</a>, and an
953 optional <a href="#visibility">visibility style</a>.</p>
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]954
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]955<h5>Syntax:</h5>
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]956<pre class="doc_code">
Duncan Sands0b23ac12008-09-12 20:48:21 +0000[diff] [blame]957@&lt;Name&gt; = alias [Linkage] [Visibility] &lt;AliaseeTy&gt; @&lt;Aliasee&gt;
Bill Wendlingaac388b2007-05-29 09:42:13 +0000[diff] [blame]958</pre>
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]959
960</div>
961
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]962<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]963<h3>
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]964 <a name="namedmetadatastructure">Named Metadata</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]965</h3>
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]966
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]967<div>
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]968
Chris Lattnere6a5ddd2010-01-15 21:50:19 +0000[diff] [blame]969<p>Named metadata is a collection of metadata. <a href="#metadata">Metadata
Dan Gohman872814a2010-07-21 18:54:18 +0000[diff] [blame]970 nodes</a> (but not metadata strings) are the only valid operands for
Chris Lattnere6a5ddd2010-01-15 21:50:19 +0000[diff] [blame]971 a named metadata.</p>
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]972
973<h5>Syntax:</h5>
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]974<pre class="doc_code">
Dan Gohman872814a2010-07-21 18:54:18 +0000[diff] [blame]975; Some unnamed metadata nodes, which are referenced by the named metadata.
976!0 = metadata !{metadata !"zero"}
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]977!1 = metadata !{metadata !"one"}
Dan Gohman872814a2010-07-21 18:54:18 +0000[diff] [blame]978!2 = metadata !{metadata !"two"}
Dan Gohman1005bc52010-07-13 19:48:13 +0000[diff] [blame]979; A named metadata.
Dan Gohman872814a2010-07-21 18:54:18 +0000[diff] [blame]980!name = !{!0, !1, !2}
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]981</pre>
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]982
983</div>
984
985<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]986<h3>
987 <a name="paramattrs">Parameter Attributes</a>
988</h3>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]989
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]990<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]991
992<p>The return type and each parameter of a function type may have a set of
993 <i>parameter attributes</i> associated with them. Parameter attributes are
994 used to communicate additional information about the result or parameters of
995 a function. Parameter attributes are considered to be part of the function,
996 not of the function type, so functions with different parameter attributes
997 can have the same function type.</p>
998
999<p>Parameter attributes are simple keywords that follow the type specified. If
1000 multiple parameter attributes are needed, they are space separated. For
1001 example:</p>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1002
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]1003<pre class="doc_code">
Nick Lewyckyb6a7d252009-02-15 23:06:14 +0000[diff] [blame]1004declare i32 @printf(i8* noalias nocapture, ...)
Chris Lattner66d922c2008-10-04 18:33:34 +0000[diff] [blame]1005declare i32 @atoi(i8 zeroext)
1006declare signext i8 @returns_signed_char()
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1007</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1008
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1009<p>Note that any attributes for the function result (<tt>nounwind</tt>,
1010 <tt>readonly</tt>) come immediately after the argument list.</p>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1011
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1012<p>Currently, only the following parameter attributes are defined:</p>
Chris Lattner47507de2008-01-11 06:20:47 +0000[diff] [blame]1013
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1014<dl>
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1015 <dt><tt><b>zeroext</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1016 <dd>This indicates to the code generator that the parameter or return value
Cameron Zwarichebe81732011-03-16 22:20:18 +0000[diff] [blame]1017 should be zero-extended to the extent required by the target's ABI (which
1018 is usually 32-bits, but is 8-bits for a i1 on x86-64) by the caller (for a
1019 parameter) or the callee (for a return value).</dd>
Chris Lattner47507de2008-01-11 06:20:47 +0000[diff] [blame]1020
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1021 <dt><tt><b>signext</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1022 <dd>This indicates to the code generator that the parameter or return value
Cameron Zwarich9e69ff92011-03-17 14:21:58 +0000[diff] [blame]1023 should be sign-extended to the extent required by the target's ABI (which
1024 is usually 32-bits) by the caller (for a parameter) or the callee (for a
1025 return value).</dd>
Chris Lattner47507de2008-01-11 06:20:47 +0000[diff] [blame]1026
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1027 <dt><tt><b>inreg</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1028 <dd>This indicates that this parameter or return value should be treated in a
1029 special target-dependent fashion during while emitting code for a function
1030 call or return (usually, by putting it in a register as opposed to memory,
1031 though some targets use it to distinguish between two different kinds of
1032 registers). Use of this attribute is target-specific.</dd>
Chris Lattner47507de2008-01-11 06:20:47 +0000[diff] [blame]1033
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1034 <dt><tt><b><a name="byval">byval</a></b></tt></dt>
Chris Lattnera6fd81d2010-11-20 23:49:06 +0000[diff] [blame]1035 <dd><p>This indicates that the pointer parameter should really be passed by
1036 value to the function. The attribute implies that a hidden copy of the
1037 pointee
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1038 is made between the caller and the callee, so the callee is unable to
1039 modify the value in the callee. This attribute is only valid on LLVM
1040 pointer arguments. It is generally used to pass structs and arrays by
1041 value, but is also valid on pointers to scalars. The copy is considered
1042 to belong to the caller not the callee (for example,
1043 <tt><a href="#readonly">readonly</a></tt> functions should not write to
1044 <tt>byval</tt> parameters). This is not a valid attribute for return
Chris Lattnera6fd81d2010-11-20 23:49:06 +0000[diff] [blame]1045 values.</p>
1046
1047 <p>The byval attribute also supports specifying an alignment with
1048 the align attribute. It indicates the alignment of the stack slot to
1049 form and the known alignment of the pointer specified to the call site. If
1050 the alignment is not specified, then the code generator makes a
1051 target-specific assumption.</p></dd>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1052
Dan Gohmanff235352010-07-02 23:18:08 +0000[diff] [blame]1053 <dt><tt><b><a name="sret">sret</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1054 <dd>This indicates that the pointer parameter specifies the address of a
1055 structure that is the return value of the function in the source program.
1056 This pointer must be guaranteed by the caller to be valid: loads and
1057 stores to the structure may be assumed by the callee to not to trap. This
1058 may only be applied to the first parameter. This is not a valid attribute
1059 for return values. </dd>
1060
Dan Gohmanff235352010-07-02 23:18:08 +0000[diff] [blame]1061 <dt><tt><b><a name="noalias">noalias</a></b></tt></dt>
Dan Gohman1e109622010-07-02 18:41:32 +0000[diff] [blame]1062 <dd>This indicates that pointer values
1063 <a href="#pointeraliasing"><i>based</i></a> on the argument or return
Dan Gohmanefca7f92010-07-02 23:46:54 +0000[diff] [blame]1064 value do not alias pointer values which are not <i>based</i> on it,
1065 ignoring certain "irrelevant" dependencies.
1066 For a call to the parent function, dependencies between memory
1067 references from before or after the call and from those during the call
1068 are "irrelevant" to the <tt>noalias</tt> keyword for the arguments and
1069 return value used in that call.
Dan Gohman1e109622010-07-02 18:41:32 +0000[diff] [blame]1070 The caller shares the responsibility with the callee for ensuring that
1071 these requirements are met.
1072 For further details, please see the discussion of the NoAlias response in
Dan Gohmanff70fe42010-07-06 15:26:33 +0000[diff] [blame]1073 <a href="AliasAnalysis.html#MustMayNo">alias analysis</a>.<br>
1074<br>
John McCall191d4ee2010-07-06 21:07:14 +0000[diff] [blame]1075 Note that this definition of <tt>noalias</tt> is intentionally
1076 similar to the definition of <tt>restrict</tt> in C99 for function
Chris Lattner211244a2010-07-06 20:51:35 +0000[diff] [blame]1077 arguments, though it is slightly weaker.
Dan Gohmanff70fe42010-07-06 15:26:33 +0000[diff] [blame]1078<br>
1079 For function return values, C99's <tt>restrict</tt> is not meaningful,
1080 while LLVM's <tt>noalias</tt> is.
1081 </dd>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1082
Dan Gohmanff235352010-07-02 23:18:08 +0000[diff] [blame]1083 <dt><tt><b><a name="nocapture">nocapture</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1084 <dd>This indicates that the callee does not make any copies of the pointer
1085 that outlive the callee itself. This is not a valid attribute for return
1086 values.</dd>
1087
Dan Gohmanff235352010-07-02 23:18:08 +0000[diff] [blame]1088 <dt><tt><b><a name="nest">nest</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1089 <dd>This indicates that the pointer parameter can be excised using the
1090 <a href="#int_trampoline">trampoline intrinsics</a>. This is not a valid
1091 attribute for return values.</dd>
1092</dl>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1093
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1094</div>
1095
1096<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1097<h3>
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]1098 <a name="gc">Garbage Collector Names</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1099</h3>
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]1100
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1101<div>
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]1102
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1103<p>Each function may specify a garbage collector name, which is simply a
1104 string:</p>
1105
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]1106<pre class="doc_code">
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1107define void @f() gc "name" { ... }
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1108</pre>
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]1109
1110<p>The compiler declares the supported values of <i>name</i>. Specifying a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1111 collector which will cause the compiler to alter its output in order to
1112 support the named garbage collection algorithm.</p>
1113
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]1114</div>
1115
1116<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1117<h3>
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1118 <a name="fnattrs">Function Attributes</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1119</h3>
Devang Patelf8b94812008-09-04 23:05:13 +0000[diff] [blame]1120
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1121<div>
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1122
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1123<p>Function attributes are set to communicate additional information about a
1124 function. Function attributes are considered to be part of the function, not
1125 of the function type, so functions with different parameter attributes can
1126 have the same function type.</p>
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 simple keywords that follow the type specified. If
1129 multiple attributes are needed, they are space separated. For example:</p>
Devang Patelf8b94812008-09-04 23:05:13 +0000[diff] [blame]1130
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]1131<pre class="doc_code">
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1132define void @f() noinline { ... }
1133define void @f() alwaysinline { ... }
1134define void @f() alwaysinline optsize { ... }
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1135define void @f() optsize { ... }
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1136</pre>
Devang Patelf8b94812008-09-04 23:05:13 +0000[diff] [blame]1137
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1138<dl>
Charles Davis1e063d12010-02-12 00:31:15 +0000[diff] [blame]1139 <dt><tt><b>alignstack(&lt;<em>n</em>&gt;)</b></tt></dt>
1140 <dd>This attribute indicates that, when emitting the prologue and epilogue,
1141 the backend should forcibly align the stack pointer. Specify the
1142 desired alignment, which must be a power of two, in parentheses.
1143
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1144 <dt><tt><b>alwaysinline</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1145 <dd>This attribute indicates that the inliner should attempt to inline this
1146 function into callers whenever possible, ignoring any active inlining size
1147 threshold for this caller.</dd>
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1148
Dan Gohman129bd562011-06-16 16:03:13 +0000[diff] [blame]1149 <dt><tt><b>nonlazybind</b></tt></dt>
1150 <dd>This attribute suppresses lazy symbol binding for the function. This
1151 may make calls to the function faster, at the cost of extra program
1152 startup time if the function is not called during program startup.</dd>
1153
Jakob Stoklund Olesen570a4a52010-02-06 01:16:28 +0000[diff] [blame]1154 <dt><tt><b>inlinehint</b></tt></dt>
1155 <dd>This attribute indicates that the source code contained a hint that inlining
1156 this function is desirable (such as the "inline" keyword in C/C++). It
1157 is just a hint; it imposes no requirements on the inliner.</dd>
1158
Nick Lewycky76ec37a2010-07-06 18:24:09 +0000[diff] [blame]1159 <dt><tt><b>naked</b></tt></dt>
1160 <dd>This attribute disables prologue / epilogue emission for the function.
1161 This can have very system-specific consequences.</dd>
1162
1163 <dt><tt><b>noimplicitfloat</b></tt></dt>
1164 <dd>This attributes disables implicit floating point instructions.</dd>
1165
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1166 <dt><tt><b>noinline</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1167 <dd>This attribute indicates that the inliner should never inline this
1168 function in any situation. This attribute may not be used together with
1169 the <tt>alwaysinline</tt> attribute.</dd>
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1170
Nick Lewycky76ec37a2010-07-06 18:24:09 +0000[diff] [blame]1171 <dt><tt><b>noredzone</b></tt></dt>
1172 <dd>This attribute indicates that the code generator should not use a red
1173 zone, even if the target-specific ABI normally permits it.</dd>
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1174
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1175 <dt><tt><b>noreturn</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1176 <dd>This function attribute indicates that the function never returns
1177 normally. This produces undefined behavior at runtime if the function
1178 ever does dynamically return.</dd>
Bill Wendling31359ba2008-11-13 01:02:51 +0000[diff] [blame]1179
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1180 <dt><tt><b>nounwind</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1181 <dd>This function attribute indicates that the function never returns with an
1182 unwind or exceptional control flow. If the function does unwind, its
1183 runtime behavior is undefined.</dd>
Bill Wendlingfbaa7ed2008-11-26 19:07:40 +0000[diff] [blame]1184
Nick Lewycky76ec37a2010-07-06 18:24:09 +0000[diff] [blame]1185 <dt><tt><b>optsize</b></tt></dt>
1186 <dd>This attribute suggests that optimization passes and code generator passes
1187 make choices that keep the code size of this function low, and otherwise
1188 do optimizations specifically to reduce code size.</dd>
1189
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1190 <dt><tt><b>readnone</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1191 <dd>This attribute indicates that the function computes its result (or decides
1192 to unwind an exception) based strictly on its arguments, without
1193 dereferencing any pointer arguments or otherwise accessing any mutable
1194 state (e.g. memory, control registers, etc) visible to caller functions.
1195 It does not write through any pointer arguments
1196 (including <tt><a href="#byval">byval</a></tt> arguments) and never
1197 changes any state visible to callers. This means that it cannot unwind
1198 exceptions by calling the <tt>C++</tt> exception throwing methods, but
1199 could use the <tt>unwind</tt> instruction.</dd>
Devang Patel5d96fda2009-06-12 19:45:19 +0000[diff] [blame]1200
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1201 <dt><tt><b><a name="readonly">readonly</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1202 <dd>This attribute indicates that the function does not write through any
1203 pointer arguments (including <tt><a href="#byval">byval</a></tt>
1204 arguments) or otherwise modify any state (e.g. memory, control registers,
1205 etc) visible to caller functions. It may dereference pointer arguments
1206 and read state that may be set in the caller. A readonly function always
1207 returns the same value (or unwinds an exception identically) when called
1208 with the same set of arguments and global state. It cannot unwind an
1209 exception by calling the <tt>C++</tt> exception throwing methods, but may
1210 use the <tt>unwind</tt> instruction.</dd>
Anton Korobeynikovc5ec8a72009-07-17 18:07:26 +0000[diff] [blame]1211
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1212 <dt><tt><b><a name="ssp">ssp</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1213 <dd>This attribute indicates that the function should emit a stack smashing
1214 protector. It is in the form of a "canary"&mdash;a random value placed on
1215 the stack before the local variables that's checked upon return from the
1216 function to see if it has been overwritten. A heuristic is used to
1217 determine if a function needs stack protectors or not.<br>
1218<br>
1219 If a function that has an <tt>ssp</tt> attribute is inlined into a
1220 function that doesn't have an <tt>ssp</tt> attribute, then the resulting
1221 function will have an <tt>ssp</tt> attribute.</dd>
1222
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1223 <dt><tt><b>sspreq</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1224 <dd>This attribute indicates that the function should <em>always</em> emit a
1225 stack smashing protector. This overrides
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1226 the <tt><a href="#ssp">ssp</a></tt> function attribute.<br>
1227<br>
1228 If a function that has an <tt>sspreq</tt> attribute is inlined into a
1229 function that doesn't have an <tt>sspreq</tt> attribute or which has
1230 an <tt>ssp</tt> attribute, then the resulting function will have
1231 an <tt>sspreq</tt> attribute.</dd>
Rafael Espindolafbff0ec2011-07-25 15:27:59 +0000[diff] [blame]1232
1233 <dt><tt><b><a name="uwtable">uwtable</a></b></tt></dt>
1234 <dd>This attribute indicates that the ABI being targeted requires that
1235 an unwind table entry be produce for this function even if we can
1236 show that no exceptions passes by it. This is normally the case for
1237 the ELF x86-64 abi, but it can be disabled for some compilation
1238 units.</dd>
1239
Rafael Espindola25456ef2011-10-03 14:45:37 +0000[diff] [blame]1240 <dt><tt><b><a name="returns_twice">returns_twice</a></b></tt></dt>
1241 <dd>This attribute indicates that this function can return
1242 twice. The C <code>setjmp</code> is an example of such a function.
1243 The compiler disables some optimizations (like tail calls) in the caller of
1244 these functions.</dd>
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1245</dl>
1246
Devang Patelf8b94812008-09-04 23:05:13 +0000[diff] [blame]1247</div>
1248
1249<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1250<h3>
Chris Lattner1eeeb0c2006-04-08 04:40:53 +0000[diff] [blame]1251 <a name="moduleasm">Module-Level Inline Assembly</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1252</h3>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1253
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1254<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1255
1256<p>Modules may contain "module-level inline asm" blocks, which corresponds to
1257 the GCC "file scope inline asm" blocks. These blocks are internally
1258 concatenated by LLVM and treated as a single unit, but may be separated in
1259 the <tt>.ll</tt> file if desired. The syntax is very simple:</p>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1260
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]1261<pre class="doc_code">
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1262module asm "inline asm code goes here"
1263module asm "more can go here"
1264</pre>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1265
1266<p>The strings can contain any character by escaping non-printable characters.
1267 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]1268 for the number.</p>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1269
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1270<p>The inline asm code is simply printed to the machine code .s file when
1271 assembly code is generated.</p>
1272
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1273</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1274
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1275<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1276<h3>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1277 <a name="datalayout">Data Layout</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1278</h3>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1279
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1280<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1281
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1282<p>A module may specify a target specific data layout string that specifies how
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1283 data is to be laid out in memory. The syntax for the data layout is
1284 simply:</p>
1285
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]1286<pre class="doc_code">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1287target datalayout = "<i>layout specification</i>"
1288</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1289
1290<p>The <i>layout specification</i> consists of a list of specifications
1291 separated by the minus sign character ('-'). Each specification starts with
1292 a letter and may include other information after the letter to define some
1293 aspect of the data layout. The specifications accepted are as follows:</p>
1294
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1295<dl>
1296 <dt><tt>E</tt></dt>
1297 <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]1298 bits with the most significance have the lowest address location.</dd>
1299
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1300 <dt><tt>e</tt></dt>
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]1301 <dd>Specifies that the target lays out data in little-endian form. That is,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1302 the bits with the least significance have the lowest address
1303 location.</dd>
1304
Lang Hamesbb5b3f32011-10-10 23:42:08 +0000[diff] [blame]1305 <dt><tt>S<i>size</i></tt></dt>
1306 <dd>Specifies the natural alignment of the stack in bits. Alignment promotion
1307 of stack variables is limited to the natural stack alignment to avoid
1308 dynamic stack realignment. The stack alignment must be a multiple of
Lang Hames5f119a62011-10-11 17:50:14 +0000[diff] [blame]1309 8-bits. If omitted, the natural stack alignment defaults to "unspecified",
1310 which does not prevent any alignment promotions.</dd>
Lang Hamesbb5b3f32011-10-10 23:42:08 +0000[diff] [blame]1311
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1312 <dt><tt>p:<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]1313 <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]1314 <i>preferred</i> alignments. All sizes are in bits. Specifying
1315 the <i>pref</i> alignment is optional. If omitted, the
1316 preceding <tt>:</tt> should be omitted too.</dd>
1317
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1318 <dt><tt>i<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1319 <dd>This specifies the alignment for an integer type of a given bit
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1320 <i>size</i>. The value of <i>size</i> must be in the range [1,2^23).</dd>
1321
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1322 <dt><tt>v<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]1323 <dd>This specifies the alignment for a vector type of a given bit
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1324 <i>size</i>.</dd>
1325
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1326 <dt><tt>f<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]1327 <dd>This specifies the alignment for a floating point type of a given bit
Dale Johannesen9d8d2212010-05-28 18:54:47 +0000[diff] [blame]1328 <i>size</i>. Only values of <i>size</i> that are supported by the target
1329 will work. 32 (float) and 64 (double) are supported on all targets;
1330 80 or 128 (different flavors of long double) are also supported on some
1331 targets.
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1332
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1333 <dt><tt>a<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1334 <dd>This specifies the alignment for an aggregate type of a given bit
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1335 <i>size</i>.</dd>
1336
Daniel Dunbar87bde0b2009-06-08 22:17:53 +0000[diff] [blame]1337 <dt><tt>s<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1338 <dd>This specifies the alignment for a stack object of a given bit
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1339 <i>size</i>.</dd>
Chris Lattnere82bdc42009-11-07 09:35:34 +0000[diff] [blame]1340
1341 <dt><tt>n<i>size1</i>:<i>size2</i>:<i>size3</i>...</tt></dt>
1342 <dd>This specifies a set of native integer widths for the target CPU
1343 in bits. For example, it might contain "n32" for 32-bit PowerPC,
1344 "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]1345 this set are considered to support most general arithmetic
Chris Lattnere82bdc42009-11-07 09:35:34 +0000[diff] [blame]1346 operations efficiently.</dd>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1347</dl>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1348
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1349<p>When constructing the data layout for a given target, LLVM starts with a
Dan Gohman1c70c002010-04-28 00:36:01 +0000[diff] [blame]1350 default set of specifications which are then (possibly) overridden by the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1351 specifications in the <tt>datalayout</tt> keyword. The default specifications
1352 are given in this list:</p>
1353
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1354<ul>
1355 <li><tt>E</tt> - big endian</li>
Dan Gohmanfdf2e8c2010-02-23 02:44:03 +0000[diff] [blame]1356 <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]1357 <li><tt>i1:8:8</tt> - i1 is 8-bit (byte) aligned</li>
1358 <li><tt>i8:8:8</tt> - i8 is 8-bit (byte) aligned</li>
1359 <li><tt>i16:16:16</tt> - i16 is 16-bit aligned</li>
1360 <li><tt>i32:32:32</tt> - i32 is 32-bit aligned</li>
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]1361 <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]1362 alignment of 64-bits</li>
1363 <li><tt>f32:32:32</tt> - float is 32-bit aligned</li>
1364 <li><tt>f64:64:64</tt> - double is 64-bit aligned</li>
1365 <li><tt>v64:64:64</tt> - 64-bit vector is 64-bit aligned</li>
1366 <li><tt>v128:128:128</tt> - 128-bit vector is 128-bit aligned</li>
1367 <li><tt>a0:0:1</tt> - aggregates are 8-bit aligned</li>
Daniel Dunbar87bde0b2009-06-08 22:17:53 +0000[diff] [blame]1368 <li><tt>s0:64:64</tt> - stack objects are 64-bit aligned</li>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1369</ul>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1370
1371<p>When LLVM is determining the alignment for a given type, it uses the
1372 following rules:</p>
1373
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1374<ol>
1375 <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]1376 specification is used.</li>
1377
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1378 <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]1379 smallest integer type that is larger than the bitwidth of the sought type
1380 is used. If none of the specifications are larger than the bitwidth then
1381 the the largest integer type is used. For example, given the default
1382 specifications above, the i7 type will use the alignment of i8 (next
1383 largest) while both i65 and i256 will use the alignment of i64 (largest
1384 specified).</li>
1385
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1386 <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]1387 largest vector type that is smaller than the sought vector type will be
1388 used as a fall back. This happens because &lt;128 x double&gt; can be
1389 implemented in terms of 64 &lt;2 x double&gt;, for example.</li>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1390</ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1391
Chris Lattner6509f502011-10-11 23:01:39 +0000[diff] [blame]1392<p>The function of the data layout string may not be what you expect. Notably,
1393 this is not a specification from the frontend of what alignment the code
1394 generator should use.</p>
1395
1396<p>Instead, if specified, the target data layout is required to match what the
1397 ultimate <em>code generator</em> expects. This string is used by the
1398 mid-level optimizers to
1399 improve code, and this only works if it matches what the ultimate code
1400 generator uses. If you would like to generate IR that does not embed this
1401 target-specific detail into the IR, then you don't have to specify the
1402 string. This will disable some optimizations that require precise layout
1403 information, but this also prevents those optimizations from introducing
1404 target specificity into the IR.</p>
1405
1406
1407
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1408</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1409
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1410<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1411<h3>
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1412 <a name="pointeraliasing">Pointer Aliasing Rules</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1413</h3>
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1414
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1415<div>
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1416
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1417<p>Any memory access must be done through a pointer value associated
Andreas Bolka99a82052009-07-27 20:37:10 +0000[diff] [blame]1418with an address range of the memory access, otherwise the behavior
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1419is undefined. Pointer values are associated with address ranges
1420according to the following rules:</p>
1421
1422<ul>
Dan Gohman1e109622010-07-02 18:41:32 +0000[diff] [blame]1423 <li>A pointer value is associated with the addresses associated with
1424 any value it is <i>based</i> on.
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1425 <li>An address of a global variable is associated with the address
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1426 range of the variable's storage.</li>
1427 <li>The result value of an allocation instruction is associated with
1428 the address range of the allocated storage.</li>
1429 <li>A null pointer in the default address-space is associated with
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1430 no address.</li>
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1431 <li>An integer constant other than zero or a pointer value returned
1432 from a function not defined within LLVM may be associated with address
1433 ranges allocated through mechanisms other than those provided by
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1434 LLVM. Such ranges shall not overlap with any ranges of addresses
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1435 allocated by mechanisms provided by LLVM.</li>
Dan Gohman1e109622010-07-02 18:41:32 +0000[diff] [blame]1436</ul>
1437
1438<p>A pointer value is <i>based</i> on another pointer value according
1439 to the following rules:</p>
1440
1441<ul>
1442 <li>A pointer value formed from a
1443 <tt><a href="#i_getelementptr">getelementptr</a></tt> operation
1444 is <i>based</i> on the first operand of the <tt>getelementptr</tt>.</li>
1445 <li>The result value of a
1446 <tt><a href="#i_bitcast">bitcast</a></tt> is <i>based</i> on the operand
1447 of the <tt>bitcast</tt>.</li>
1448 <li>A pointer value formed by an
1449 <tt><a href="#i_inttoptr">inttoptr</a></tt> is <i>based</i> on all
1450 pointer values that contribute (directly or indirectly) to the
1451 computation of the pointer's value.</li>
1452 <li>The "<i>based</i> on" relationship is transitive.</li>
1453</ul>
1454
1455<p>Note that this definition of <i>"based"</i> is intentionally
1456 similar to the definition of <i>"based"</i> in C99, though it is
1457 slightly weaker.</p>
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1458
1459<p>LLVM IR does not associate types with memory. The result type of a
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1460<tt><a href="#i_load">load</a></tt> merely indicates the size and
1461alignment of the memory from which to load, as well as the
Dan Gohmanc22c0f32010-06-17 19:23:50 +0000[diff] [blame]1462interpretation of the value. The first operand type of a
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1463<tt><a href="#i_store">store</a></tt> similarly only indicates the size
1464and alignment of the store.</p>
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1465
1466<p>Consequently, type-based alias analysis, aka TBAA, aka
1467<tt>-fstrict-aliasing</tt>, is not applicable to general unadorned
1468LLVM IR. <a href="#metadata">Metadata</a> may be used to encode
1469additional information which specialized optimization passes may use
1470to implement type-based alias analysis.</p>
1471
1472</div>
1473
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]1474<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1475<h3>
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]1476 <a name="volatile">Volatile Memory Accesses</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1477</h3>
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]1478
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1479<div>
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]1480
1481<p>Certain memory accesses, such as <a href="#i_load"><tt>load</tt></a>s, <a
1482href="#i_store"><tt>store</tt></a>s, and <a
1483href="#int_memcpy"><tt>llvm.memcpy</tt></a>s may be marked <tt>volatile</tt>.
1484The optimizers must not change the number of volatile operations or change their
1485order of execution relative to other volatile operations. The optimizers
1486<i>may</i> change the order of volatile operations relative to non-volatile
1487operations. This is not Java's "volatile" and has no cross-thread
1488synchronization behavior.</p>
1489
1490</div>
1491
Eli Friedman5b60e1b2011-07-20 21:35:53 +0000[diff] [blame]1492<!-- ======================================================================= -->
1493<h3>
1494 <a name="memmodel">Memory Model for Concurrent Operations</a>
1495</h3>
1496
1497<div>
1498
1499<p>The LLVM IR does not define any way to start parallel threads of execution
1500or to register signal handlers. Nonetheless, there are platform-specific
1501ways to create them, and we define LLVM IR's behavior in their presence. This
1502model is inspired by the C++0x memory model.</p>
1503
Eli Friedman234bccd2011-08-22 21:35:27 +0000[diff] [blame]1504<p>For a more informal introduction to this model, see the
1505<a href="Atomics.html">LLVM Atomic Instructions and Concurrency Guide</a>.
1506
Eli Friedman5b60e1b2011-07-20 21:35:53 +0000[diff] [blame]1507<p>We define a <i>happens-before</i> partial order as the least partial order
1508that</p>
1509<ul>
1510 <li>Is a superset of single-thread program order, and</li>
1511 <li>When a <i>synchronizes-with</i> <tt>b</tt>, includes an edge from
1512 <tt>a</tt> to <tt>b</tt>. <i>Synchronizes-with</i> pairs are introduced
1513 by platform-specific techniques, like pthread locks, thread
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1514 creation, thread joining, etc., and by atomic instructions.
1515 (See also <a href="#ordering">Atomic Memory Ordering Constraints</a>).
1516 </li>
Eli Friedman5b60e1b2011-07-20 21:35:53 +0000[diff] [blame]1517</ul>
1518
1519<p>Note that program order does not introduce <i>happens-before</i> edges
1520between a thread and signals executing inside that thread.</p>
1521
1522<p>Every (defined) read operation (load instructions, memcpy, atomic
1523loads/read-modify-writes, etc.) <var>R</var> reads a series of bytes written by
1524(defined) write operations (store instructions, atomic
Eli Friedman118973a2011-07-22 03:04:45 +0000[diff] [blame]1525stores/read-modify-writes, memcpy, etc.). For the purposes of this section,
1526initialized globals are considered to have a write of the initializer which is
1527atomic and happens before any other read or write of the memory in question.
1528For each byte of a read <var>R</var>, <var>R<sub>byte</sub></var> may see
1529any write to the same byte, except:</p>
Eli Friedman5b60e1b2011-07-20 21:35:53 +0000[diff] [blame]1530
1531<ul>
1532 <li>If <var>write<sub>1</sub></var> happens before
1533 <var>write<sub>2</sub></var>, and <var>write<sub>2</sub></var> happens
1534 before <var>R<sub>byte</sub></var>, then <var>R<sub>byte</sub></var>
Eli Friedman118973a2011-07-22 03:04:45 +0000[diff] [blame]1535 does not see <var>write<sub>1</sub></var>.
Bill Wendling0246bb72011-07-31 06:45:03 +0000[diff] [blame]1536 <li>If <var>R<sub>byte</sub></var> happens before
1537 <var>write<sub>3</sub></var>, then <var>R<sub>byte</sub></var> does not
1538 see <var>write<sub>3</sub></var>.
Eli Friedman5b60e1b2011-07-20 21:35:53 +0000[diff] [blame]1539</ul>
1540
1541<p>Given that definition, <var>R<sub>byte</sub></var> is defined as follows:
1542<ul>
Eli Friedman234bccd2011-08-22 21:35:27 +0000[diff] [blame]1543 <li>If <var>R</var> is volatile, the result is target-dependent. (Volatile
1544 is supposed to give guarantees which can support
1545 <code>sig_atomic_t</code> in C/C++, and may be used for accesses to
1546 addresses which do not behave like normal memory. It does not generally
1547 provide cross-thread synchronization.)
1548 <li>Otherwise, if there is no write to the same byte that happens before
Eli Friedman5b60e1b2011-07-20 21:35:53 +0000[diff] [blame]1549 <var>R<sub>byte</sub></var>, <var>R<sub>byte</sub></var> returns
1550 <tt>undef</tt> for that byte.
Eli Friedman118973a2011-07-22 03:04:45 +0000[diff] [blame]1551 <li>Otherwise, if <var>R<sub>byte</sub></var> may see exactly one write,
Eli Friedman5b60e1b2011-07-20 21:35:53 +0000[diff] [blame]1552 <var>R<sub>byte</sub></var> returns the value written by that
1553 write.</li>
Eli Friedman118973a2011-07-22 03:04:45 +0000[diff] [blame]1554 <li>Otherwise, if <var>R</var> is atomic, and all the writes
1555 <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]1556 values written. See the <a href="#ordering">Atomic Memory Ordering
1557 Constraints</a> section for additional constraints on how the choice
1558 is made.
Eli Friedman5b60e1b2011-07-20 21:35:53 +0000[diff] [blame]1559 <li>Otherwise <var>R<sub>byte</sub></var> returns <tt>undef</tt>.</li>
1560</ul>
1561
1562<p><var>R</var> returns the value composed of the series of bytes it read.
1563This implies that some bytes within the value may be <tt>undef</tt>
1564<b>without</b> the entire value being <tt>undef</tt>. Note that this only
1565defines the semantics of the operation; it doesn't mean that targets will
1566emit more than one instruction to read the series of bytes.</p>
1567
1568<p>Note that in cases where none of the atomic intrinsics are used, this model
1569places only one restriction on IR transformations on top of what is required
1570for single-threaded execution: introducing a store to a byte which might not
Eli Friedman101c81d2011-08-02 01:15:34 +0000[diff] [blame]1571otherwise be stored is not allowed in general. (Specifically, in the case
1572where another thread might write to and read from an address, introducing a
1573store can change a load that may see exactly one write into a load that may
1574see multiple writes.)</p>
Eli Friedman5b60e1b2011-07-20 21:35:53 +0000[diff] [blame]1575
1576<!-- FIXME: This model assumes all targets where concurrency is relevant have
1577a byte-size store which doesn't affect adjacent bytes. As far as I can tell,
1578none of the backends currently in the tree fall into this category; however,
1579there might be targets which care. If there are, we want a paragraph
1580like the following:
1581
1582Targets may specify that stores narrower than a certain width are not
1583available; on such a target, for the purposes of this model, treat any
1584non-atomic write with an alignment or width less than the minimum width
1585as if it writes to the relevant surrounding bytes.
1586-->
1587
1588</div>
1589
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1590<!-- ======================================================================= -->
NAKAMURA Takumib5bb29c2011-08-12 06:17:17 +0000[diff] [blame]1591<h3>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1592 <a name="ordering">Atomic Memory Ordering Constraints</a>
NAKAMURA Takumib5bb29c2011-08-12 06:17:17 +0000[diff] [blame]1593</h3>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1594
NAKAMURA Takumib5bb29c2011-08-12 06:17:17 +0000[diff] [blame]1595<div>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1596
1597<p>Atomic instructions (<a href="#i_cmpxchg"><code>cmpxchg</code></a>,
Eli Friedman21006d42011-08-09 23:02:53 +0000[diff] [blame]1598<a href="#i_atomicrmw"><code>atomicrmw</code></a>,
1599<a href="#i_fence"><code>fence</code></a>,
1600<a href="#i_load"><code>atomic load</code></a>, and
Eli Friedman8fa281a2011-08-09 23:26:12 +0000[diff] [blame]1601<a href="#i_store"><code>atomic store</code></a>) take an ordering parameter
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1602that determines which other atomic instructions on the same address they
1603<i>synchronize with</i>. These semantics are borrowed from Java and C++0x,
1604but are somewhat more colloquial. If these descriptions aren't precise enough,
Eli Friedman234bccd2011-08-22 21:35:27 +0000[diff] [blame]1605check those specs (see spec references in the
1606<a href="Atomic.html#introduction">atomics guide</a>).
1607<a href="#i_fence"><code>fence</code></a> instructions
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1608treat these orderings somewhat differently since they don't take an address.
1609See that instruction's documentation for details.</p>
1610
Eli Friedman234bccd2011-08-22 21:35:27 +0000[diff] [blame]1611<p>For a simpler introduction to the ordering constraints, see the
1612<a href="Atomics.html">LLVM Atomic Instructions and Concurrency Guide</a>.</p>
1613
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1614<dl>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1615<dt><code>unordered</code></dt>
1616<dd>The set of values that can be read is governed by the happens-before
1617partial order. A value cannot be read unless some operation wrote it.
1618This is intended to provide a guarantee strong enough to model Java's
1619non-volatile shared variables. This ordering cannot be specified for
1620read-modify-write operations; it is not strong enough to make them atomic
1621in any interesting way.</dd>
1622<dt><code>monotonic</code></dt>
1623<dd>In addition to the guarantees of <code>unordered</code>, there is a single
1624total order for modifications by <code>monotonic</code> operations on each
1625address. All modification orders must be compatible with the happens-before
1626order. There is no guarantee that the modification orders can be combined to
1627a global total order for the whole program (and this often will not be
1628possible). The read in an atomic read-modify-write operation
1629(<a href="#i_cmpxchg"><code>cmpxchg</code></a> and
1630<a href="#i_atomicrmw"><code>atomicrmw</code></a>)
1631reads the value in the modification order immediately before the value it
1632writes. If one atomic read happens before another atomic read of the same
1633address, the later read must see the same value or a later value in the
1634address's modification order. This disallows reordering of
1635<code>monotonic</code> (or stronger) operations on the same address. If an
1636address is written <code>monotonic</code>ally by one thread, and other threads
1637<code>monotonic</code>ally read that address repeatedly, the other threads must
Eli Friedman234bccd2011-08-22 21:35:27 +0000[diff] [blame]1638eventually see the write. This corresponds to the C++0x/C1x
1639<code>memory_order_relaxed</code>.</dd>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1640<dt><code>acquire</code></dt>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1641<dd>In addition to the guarantees of <code>monotonic</code>,
Eli Friedmanc264b2f2011-08-24 20:28:39 +0000[diff] [blame]1642a <i>synchronizes-with</i> edge may be formed with a <code>release</code>
1643operation. This is intended to model C++'s <code>memory_order_acquire</code>.</dd>
1644<dt><code>release</code></dt>
1645<dd>In addition to the guarantees of <code>monotonic</code>, if this operation
1646writes a value which is subsequently read by an <code>acquire</code> operation,
1647it <i>synchronizes-with</i> that operation. (This isn't a complete
1648description; see the C++0x definition of a release sequence.) This corresponds
1649to the C++0x/C1x <code>memory_order_release</code>.</dd>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1650<dt><code>acq_rel</code> (acquire+release)</dt><dd>Acts as both an
Eli Friedman234bccd2011-08-22 21:35:27 +0000[diff] [blame]1651<code>acquire</code> and <code>release</code> operation on its address.
1652This corresponds to the C++0x/C1x <code>memory_order_acq_rel</code>.</dd>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1653<dt><code>seq_cst</code> (sequentially consistent)</dt><dd>
1654<dd>In addition to the guarantees of <code>acq_rel</code>
1655(<code>acquire</code> for an operation which only reads, <code>release</code>
1656for an operation which only writes), there is a global total order on all
1657sequentially-consistent operations on all addresses, which is consistent with
1658the <i>happens-before</i> partial order and with the modification orders of
1659all the affected addresses. Each sequentially-consistent read sees the last
Eli Friedman234bccd2011-08-22 21:35:27 +0000[diff] [blame]1660preceding write to the same address in this global order. This corresponds
1661to the C++0x/C1x <code>memory_order_seq_cst</code> and Java volatile.</dd>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1662</dl>
1663
1664<p id="singlethread">If an atomic operation is marked <code>singlethread</code>,
1665it only <i>synchronizes with</i> or participates in modification and seq_cst
1666total orderings with other operations running in the same thread (for example,
1667in signal handlers).</p>
1668
1669</div>
1670
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1671</div>
1672
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1673<!-- *********************************************************************** -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1674<h2><a name="typesystem">Type System</a></h2>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1675<!-- *********************************************************************** -->
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1676
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1677<div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1678
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1679<p>The LLVM type system is one of the most important features of the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1680 intermediate representation. Being typed enables a number of optimizations
1681 to be performed on the intermediate representation directly, without having
1682 to do extra analyses on the side before the transformation. A strong type
1683 system makes it easier to read the generated code and enables novel analyses
1684 and transformations that are not feasible to perform on normal three address
1685 code representations.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1686
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1687<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1688<h3>
1689 <a name="t_classifications">Type Classifications</a>
1690</h3>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1691
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1692<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1693
1694<p>The types fall into a few useful classifications:</p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1695
1696<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1697 <tbody>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1698 <tr><th>Classification</th><th>Types</th></tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1699 <tr>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1700 <td><a href="#t_integer">integer</a></td>
Reid Spencer2b916312007-05-16 18:44:01 +0000[diff] [blame]1701 <td><tt>i1, i2, i3, ... i8, ... i16, ... i32, ... i64, ... </tt></td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1702 </tr>
1703 <tr>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1704 <td><a href="#t_floating">floating point</a></td>
1705 <td><tt>float, double, x86_fp80, fp128, ppc_fp128</tt></td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1706 </tr>
1707 <tr>
1708 <td><a name="t_firstclass">first class</a></td>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1709 <td><a href="#t_integer">integer</a>,
1710 <a href="#t_floating">floating point</a>,
1711 <a href="#t_pointer">pointer</a>,
Dan Gohman0066db62008-06-18 18:42:13 +0000[diff] [blame]1712 <a href="#t_vector">vector</a>,
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]1713 <a href="#t_struct">structure</a>,
1714 <a href="#t_array">array</a>,
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1715 <a href="#t_label">label</a>,
1716 <a href="#t_metadata">metadata</a>.
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1717 </td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1718 </tr>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1719 <tr>
1720 <td><a href="#t_primitive">primitive</a></td>
1721 <td><a href="#t_label">label</a>,
1722 <a href="#t_void">void</a>,
Tobias Grosser05387292010-12-28 20:29:31 +0000[diff] [blame]1723 <a href="#t_integer">integer</a>,
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1724 <a href="#t_floating">floating point</a>,
Dale Johannesen21fe99b2010-10-01 00:48:59 +0000[diff] [blame]1725 <a href="#t_x86mmx">x86mmx</a>,
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1726 <a href="#t_metadata">metadata</a>.</td>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1727 </tr>
1728 <tr>
1729 <td><a href="#t_derived">derived</a></td>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]1730 <td><a href="#t_array">array</a>,
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1731 <a href="#t_function">function</a>,
1732 <a href="#t_pointer">pointer</a>,
1733 <a href="#t_struct">structure</a>,
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1734 <a href="#t_vector">vector</a>,
1735 <a href="#t_opaque">opaque</a>.
Dan Gohman01ac1012008-10-14 16:32:04 +0000[diff] [blame]1736 </td>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1737 </tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1738 </tbody>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1739</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1740
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1741<p>The <a href="#t_firstclass">first class</a> types are perhaps the most
1742 important. Values of these types are the only ones which can be produced by
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]1743 instructions.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1744
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1745</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1746
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1747<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1748<h3>
1749 <a name="t_primitive">Primitive Types</a>
1750</h3>
Chris Lattner8f8c7b72008-01-04 04:34:14 +0000[diff] [blame]1751
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1752<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1753
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1754<p>The primitive types are the fundamental building blocks of the LLVM
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1755 system.</p>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1756
1757<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1758<h4>
1759 <a name="t_integer">Integer Type</a>
1760</h4>
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]1761
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1762<div>
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]1763
1764<h5>Overview:</h5>
1765<p>The integer type is a very simple type that simply specifies an arbitrary
1766 bit width for the integer type desired. Any bit width from 1 bit to
1767 2<sup>23</sup>-1 (about 8 million) can be specified.</p>
1768
1769<h5>Syntax:</h5>
1770<pre>
1771 iN
1772</pre>
1773
1774<p>The number of bits the integer will occupy is specified by the <tt>N</tt>
1775 value.</p>
1776
1777<h5>Examples:</h5>
1778<table class="layout">
1779 <tr class="layout">
1780 <td class="left"><tt>i1</tt></td>
1781 <td class="left">a single-bit integer.</td>
1782 </tr>
1783 <tr class="layout">
1784 <td class="left"><tt>i32</tt></td>
1785 <td class="left">a 32-bit integer.</td>
1786 </tr>
1787 <tr class="layout">
1788 <td class="left"><tt>i1942652</tt></td>
1789 <td class="left">a really big integer of over 1 million bits.</td>
1790 </tr>
1791</table>
1792
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]1793</div>
1794
1795<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1796<h4>
1797 <a name="t_floating">Floating Point Types</a>
1798</h4>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1799
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1800<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1801
1802<table>
1803 <tbody>
1804 <tr><th>Type</th><th>Description</th></tr>
1805 <tr><td><tt>float</tt></td><td>32-bit floating point value</td></tr>
1806 <tr><td><tt>double</tt></td><td>64-bit floating point value</td></tr>
1807 <tr><td><tt>fp128</tt></td><td>128-bit floating point value (112-bit mantissa)</td></tr>
1808 <tr><td><tt>x86_fp80</tt></td><td>80-bit floating point value (X87)</td></tr>
1809 <tr><td><tt>ppc_fp128</tt></td><td>128-bit floating point value (two 64-bits)</td></tr>
1810 </tbody>
1811</table>
1812
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1813</div>
1814
1815<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1816<h4>
1817 <a name="t_x86mmx">X86mmx Type</a>
1818</h4>
Dale Johannesen21fe99b2010-10-01 00:48:59 +0000[diff] [blame]1819
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1820<div>
Dale Johannesen21fe99b2010-10-01 00:48:59 +0000[diff] [blame]1821
1822<h5>Overview:</h5>
1823<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>
1824
1825<h5>Syntax:</h5>
1826<pre>
Dale Johannesen473a8c82010-10-01 01:07:02 +0000[diff] [blame]1827 x86mmx
Dale Johannesen21fe99b2010-10-01 00:48:59 +0000[diff] [blame]1828</pre>
1829
1830</div>
1831
1832<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1833<h4>
1834 <a name="t_void">Void Type</a>
1835</h4>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1836
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1837<div>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1838
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1839<h5>Overview:</h5>
1840<p>The void type does not represent any value and has no size.</p>
1841
1842<h5>Syntax:</h5>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1843<pre>
1844 void
1845</pre>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1846
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1847</div>
1848
1849<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1850<h4>
1851 <a name="t_label">Label Type</a>
1852</h4>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1853
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1854<div>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1855
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1856<h5>Overview:</h5>
1857<p>The label type represents code labels.</p>
1858
1859<h5>Syntax:</h5>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1860<pre>
1861 label
1862</pre>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1863
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1864</div>
1865
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1866<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1867<h4>
1868 <a name="t_metadata">Metadata Type</a>
1869</h4>
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1870
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1871<div>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1872
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1873<h5>Overview:</h5>
Nick Lewyckyc261df92009-09-27 23:27:42 +0000[diff] [blame]1874<p>The metadata type represents embedded metadata. No derived types may be
1875 created from metadata except for <a href="#t_function">function</a>
1876 arguments.
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1877
1878<h5>Syntax:</h5>
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1879<pre>
1880 metadata
1881</pre>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1882
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1883</div>
1884
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1885</div>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1886
1887<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1888<h3>
1889 <a name="t_derived">Derived Types</a>
1890</h3>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1891
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1892<div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1893
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1894<p>The real power in LLVM comes from the derived types in the system. This is
1895 what allows a programmer to represent arrays, functions, pointers, and other
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]1896 useful types. Each of these types contain one or more element types which
1897 may be a primitive type, or another derived type. For example, it is
1898 possible to have a two dimensional array, using an array as the element type
1899 of another array.</p>
Dan Gohmand8791e52009-01-24 15:58:40 +0000[diff] [blame]1900
Chris Lattner1afcace2011-07-09 17:41:24 +0000[diff] [blame]1901</div>
1902
1903
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]1904<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1905<h4>
1906 <a name="t_aggregate">Aggregate Types</a>
1907</h4>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]1908
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1909<div>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]1910
1911<p>Aggregate Types are a subset of derived types that can contain multiple
1912 member types. <a href="#t_array">Arrays</a>,
Chris Lattner61c70e92010-08-28 04:09:24 +0000[diff] [blame]1913 <a href="#t_struct">structs</a>, and <a href="#t_vector">vectors</a> are
1914 aggregate types.</p>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]1915
1916</div>
1917
Reid Spencer2b916312007-05-16 18:44:01 +0000[diff] [blame]1918<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1919<h4>
1920 <a name="t_array">Array Type</a>
1921</h4>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1922
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1923<div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1924
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1925<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1926<p>The array type is a very simple derived type that arranges elements
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1927 sequentially in memory. The array type requires a size (number of elements)
1928 and an underlying data type.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1929
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1930<h5>Syntax:</h5>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1931<pre>
1932 [&lt;# elements&gt; x &lt;elementtype&gt;]
1933</pre>
1934
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1935<p>The number of elements is a constant integer value; <tt>elementtype</tt> may
1936 be any type with a size.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1937
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1938<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1939<table class="layout">
1940 <tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1941 <td class="left"><tt>[40 x i32]</tt></td>
1942 <td class="left">Array of 40 32-bit integer values.</td>
1943 </tr>
1944 <tr class="layout">
1945 <td class="left"><tt>[41 x i32]</tt></td>
1946 <td class="left">Array of 41 32-bit integer values.</td>
1947 </tr>
1948 <tr class="layout">
1949 <td class="left"><tt>[4 x i8]</tt></td>
1950 <td class="left">Array of 4 8-bit integer values.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1951 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1952</table>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1953<p>Here are some examples of multidimensional arrays:</p>
1954<table class="layout">
1955 <tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1956 <td class="left"><tt>[3 x [4 x i32]]</tt></td>
1957 <td class="left">3x4 array of 32-bit integer values.</td>
1958 </tr>
1959 <tr class="layout">
1960 <td class="left"><tt>[12 x [10 x float]]</tt></td>
1961 <td class="left">12x10 array of single precision floating point values.</td>
1962 </tr>
1963 <tr class="layout">
1964 <td class="left"><tt>[2 x [3 x [4 x i16]]]</tt></td>
1965 <td class="left">2x3x4 array of 16-bit integer values.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1966 </tr>
1967</table>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]1968
Dan Gohman7657f6b2009-11-09 19:01:53 +0000[diff] [blame]1969<p>There is no restriction on indexing beyond the end of the array implied by
1970 a static type (though there are restrictions on indexing beyond the bounds
1971 of an allocated object in some cases). This means that single-dimension
1972 'variable sized array' addressing can be implemented in LLVM with a zero
1973 length array type. An implementation of 'pascal style arrays' in LLVM could
1974 use the type "<tt>{ i32, [0 x float]}</tt>", for example.</p>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]1975
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1976</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1977
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1978<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1979<h4>
1980 <a name="t_function">Function Type</a>
1981</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1982
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1983<div>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]1984
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1985<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1986<p>The function type can be thought of as a function signature. It consists of
1987 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]1988 function type is a first class type or a void type.</p>
Devang Patelc3fc6df2008-03-10 20:49:15 +0000[diff] [blame]1989
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1990<h5>Syntax:</h5>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]1991<pre>
Nick Lewycky51386942009-09-27 07:55:32 +0000[diff] [blame]1992 &lt;returntype&gt; (&lt;parameter list&gt;)
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]1993</pre>
1994
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]1995<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]1996 specifiers. Optionally, the parameter list may include a type <tt>...</tt>,
1997 which indicates that the function takes a variable number of arguments.
1998 Variable argument functions can access their arguments with
1999 the <a href="#int_varargs">variable argument handling intrinsic</a>
Chris Lattner0724fbd2010-03-02 06:36:51 +0000[diff] [blame]2000 functions. '<tt>&lt;returntype&gt;</tt>' is any type except
Nick Lewyckyc261df92009-09-27 23:27:42 +0000[diff] [blame]2001 <a href="#t_label">label</a>.</p>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]2002
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2003<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]2004<table class="layout">
2005 <tr class="layout">
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]2006 <td class="left"><tt>i32 (i32)</tt></td>
2007 <td class="left">function taking an <tt>i32</tt>, returning an <tt>i32</tt>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]2008 </td>
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]2009 </tr><tr class="layout">
Chris Lattner0724fbd2010-03-02 06:36:51 +0000[diff] [blame]2010 <td class="left"><tt>float&nbsp;(i16,&nbsp;i32&nbsp;*)&nbsp;*
Reid Spencerf17a0b72006-12-31 07:20:23 +0000[diff] [blame]2011 </tt></td>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]2012 <td class="left"><a href="#t_pointer">Pointer</a> to a function that takes
Chris Lattner0724fbd2010-03-02 06:36:51 +0000[diff] [blame]2013 an <tt>i16</tt> and a <a href="#t_pointer">pointer</a> to <tt>i32</tt>,
2014 returning <tt>float</tt>.
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]2015 </td>
2016 </tr><tr class="layout">
2017 <td class="left"><tt>i32 (i8*, ...)</tt></td>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]2018 <td class="left">A vararg function that takes at least one
2019 <a href="#t_pointer">pointer</a> to <tt>i8 </tt> (char in C),
2020 which returns an integer. This is the signature for <tt>printf</tt> in
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]2021 LLVM.
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]2022 </td>
Devang Patela582f402008-03-24 05:35:41 +0000[diff] [blame]2023 </tr><tr class="layout">
2024 <td class="left"><tt>{i32, i32} (i32)</tt></td>
Nick Lewycky51386942009-09-27 07:55:32 +0000[diff] [blame]2025 <td class="left">A function taking an <tt>i32</tt>, returning a
2026 <a href="#t_struct">structure</a> containing two <tt>i32</tt> values
Devang Patela582f402008-03-24 05:35:41 +0000[diff] [blame]2027 </td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]2028 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2029</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]2030
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2031</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2032
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2033<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2034<h4>
2035 <a name="t_struct">Structure Type</a>
2036</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2037
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2038<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2039
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2040<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2041<p>The structure type is used to represent a collection of data members together
Chris Lattner1afcace2011-07-09 17:41:24 +0000[diff] [blame]2042 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]2043
Jeffrey Yasskin7a088cf2010-01-11 19:19:26 +0000[diff] [blame]2044<p>Structures in memory are accessed using '<tt><a href="#i_load">load</a></tt>'
2045 and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a field
2046 with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.
2047 Structures in registers are accessed using the
2048 '<tt><a href="#i_extractvalue">extractvalue</a></tt>' and
2049 '<tt><a href="#i_insertvalue">insertvalue</a></tt>' instructions.</p>
Chris Lattner1afcace2011-07-09 17:41:24 +0000[diff] [blame]2050
2051<p>Structures may optionally be "packed" structures, which indicate that the
2052 alignment of the struct is one byte, and that there is no padding between
Chris Lattner2c38d652011-08-12 17:31:02 +0000[diff] [blame]2053 the elements. In non-packed structs, padding between field types is inserted
2054 as defined by the TargetData string in the module, which is required to match
Chris Lattnere4617b02011-10-11 23:02:17 +0000[diff] [blame]2055 what the underlying code generator expects.</p>
Chris Lattner1afcace2011-07-09 17:41:24 +0000[diff] [blame]2056
Chris Lattner2c38d652011-08-12 17:31:02 +0000[diff] [blame]2057<p>Structures can either be "literal" or "identified". A literal structure is
2058 defined inline with other types (e.g. <tt>{i32, i32}*</tt>) whereas identified
2059 types are always defined at the top level with a name. Literal types are
2060 uniqued by their contents and can never be recursive or opaque since there is
Chris Lattneraa175c32011-08-12 18:12:40 +0000[diff] [blame]2061 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]2062 never uniqued.
Chris Lattner1afcace2011-07-09 17:41:24 +0000[diff] [blame]2063</p>
2064
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2065<h5>Syntax:</h5>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]2066<pre>
Chris Lattner2c38d652011-08-12 17:31:02 +0000[diff] [blame]2067 %T1 = type { &lt;type list&gt; } <i>; Identified normal struct type</i>
2068 %T2 = type &lt;{ &lt;type list&gt; }&gt; <i>; Identified packed struct type</i>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]2069</pre>
Chris Lattner1afcace2011-07-09 17:41:24 +0000[diff] [blame]2070
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2071<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]2072<table class="layout">
2073 <tr class="layout">
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]2074 <td class="left"><tt>{ i32, i32, i32 }</tt></td>
2075 <td class="left">A triple of three <tt>i32</tt> values</td>
Chris Lattner1afcace2011-07-09 17:41:24 +0000[diff] [blame]2076 </tr>
2077 <tr class="layout">
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]2078 <td class="left"><tt>{&nbsp;float,&nbsp;i32&nbsp;(i32)&nbsp;*&nbsp;}</tt></td>
2079 <td class="left">A pair, where the first element is a <tt>float</tt> and the
2080 second element is a <a href="#t_pointer">pointer</a> to a
2081 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
2082 an <tt>i32</tt>.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]2083 </tr>
Chris Lattner1afcace2011-07-09 17:41:24 +0000[diff] [blame]2084 <tr class="layout">
2085 <td class="left"><tt>&lt;{ i8, i32 }&gt;</tt></td>
2086 <td class="left">A packed struct known to be 5 bytes in size.</td>
2087 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2088</table>
Dan Gohmand8791e52009-01-24 15:58:40 +0000[diff] [blame]2089
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2090</div>
Chris Lattner1afcace2011-07-09 17:41:24 +0000[diff] [blame]2091
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2092<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2093<h4>
Chris Lattner628ed392011-07-23 19:59:08 +0000[diff] [blame]2094 <a name="t_opaque">Opaque Structure Types</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2095</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2096
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2097<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2098
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]2099<h5>Overview:</h5>
Chris Lattner628ed392011-07-23 19:59:08 +0000[diff] [blame]2100<p>Opaque structure types are used to represent named structure types that do
2101 not have a body specified. This corresponds (for example) to the C notion of
2102 a forward declared structure.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2103
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]2104<h5>Syntax:</h5>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]2105<pre>
Chris Lattner1afcace2011-07-09 17:41:24 +0000[diff] [blame]2106 %X = type opaque
2107 %52 = type opaque
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]2108</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2109
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]2110<h5>Examples:</h5>
2111<table class="layout">
2112 <tr class="layout">
Chris Lattner1afcace2011-07-09 17:41:24 +0000[diff] [blame]2113 <td class="left"><tt>opaque</tt></td>
2114 <td class="left">An opaque type.</td>
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]2115 </tr>
2116</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2117
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]2118</div>
2119
Chris Lattner1afcace2011-07-09 17:41:24 +0000[diff] [blame]2120
2121
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]2122<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2123<h4>
2124 <a name="t_pointer">Pointer Type</a>
2125</h4>
Chris Lattner0fd4a272009-02-08 19:53:29 +0000[diff] [blame]2126
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2127<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2128
2129<h5>Overview:</h5>
Dan Gohmanff3ef322010-02-25 16:50:07 +0000[diff] [blame]2130<p>The pointer type is used to specify memory locations.
2131 Pointers are commonly used to reference objects in memory.</p>
2132
2133<p>Pointer types may have an optional address space attribute defining the
2134 numbered address space where the pointed-to object resides. The default
2135 address space is number zero. The semantics of non-zero address
2136 spaces are target-specific.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2137
2138<p>Note that LLVM does not permit pointers to void (<tt>void*</tt>) nor does it
2139 permit pointers to labels (<tt>label*</tt>). Use <tt>i8*</tt> instead.</p>
Chris Lattner0fd4a272009-02-08 19:53:29 +0000[diff] [blame]2140
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2141<h5>Syntax:</h5>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]2142<pre>
2143 &lt;type&gt; *
2144</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2145
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2146<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]2147<table class="layout">
2148 <tr class="layout">
Dan Gohman2a08c532009-01-04 23:44:43 +0000[diff] [blame]2149 <td class="left"><tt>[4 x i32]*</tt></td>
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]2150 <td class="left">A <a href="#t_pointer">pointer</a> to <a
2151 href="#t_array">array</a> of four <tt>i32</tt> values.</td>
2152 </tr>
2153 <tr class="layout">
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]2154 <td class="left"><tt>i32 (i32*) *</tt></td>
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]2155 <td class="left"> A <a href="#t_pointer">pointer</a> to a <a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2156 href="#t_function">function</a> that takes an <tt>i32*</tt>, returning an
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]2157 <tt>i32</tt>.</td>
2158 </tr>
2159 <tr class="layout">
2160 <td class="left"><tt>i32 addrspace(5)*</tt></td>
2161 <td class="left">A <a href="#t_pointer">pointer</a> to an <tt>i32</tt> value
2162 that resides in address space #5.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]2163 </tr>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2164</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2165
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2166</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]2167
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]2168<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2169<h4>
2170 <a name="t_vector">Vector Type</a>
2171</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2172
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2173<div>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]2174
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]2175<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2176<p>A vector type is a simple derived type that represents a vector of elements.
2177 Vector types are used when multiple primitive data are operated in parallel
2178 using a single instruction (SIMD). A vector type requires a size (number of
Duncan Sandsd40d14e2009-11-27 13:38:03 +0000[diff] [blame]2179 elements) and an underlying primitive data type. Vector types are considered
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2180 <a href="#t_firstclass">first class</a>.</p>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]2181
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]2182<h5>Syntax:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]2183<pre>
2184 &lt; &lt;# elements&gt; x &lt;elementtype&gt; &gt;
2185</pre>
2186
Chris Lattner7d2e7be2010-10-10 18:20:35 +0000[diff] [blame]2187<p>The number of elements is a constant integer value larger than 0; elementtype
2188 may be any integer or floating point type. Vectors of size zero are not
2189 allowed, and pointers are not allowed as the element type.</p>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]2190
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]2191<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]2192<table class="layout">
2193 <tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]2194 <td class="left"><tt>&lt;4 x i32&gt;</tt></td>
2195 <td class="left">Vector of 4 32-bit integer values.</td>
2196 </tr>
2197 <tr class="layout">
2198 <td class="left"><tt>&lt;8 x float&gt;</tt></td>
2199 <td class="left">Vector of 8 32-bit floating-point values.</td>
2200 </tr>
2201 <tr class="layout">
2202 <td class="left"><tt>&lt;2 x i64&gt;</tt></td>
2203 <td class="left">Vector of 2 64-bit integer values.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]2204 </tr>
2205</table>
Dan Gohmand8791e52009-01-24 15:58:40 +0000[diff] [blame]2206
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2207</div>
2208
Bill Wendlingaf75f0c2011-07-31 06:47:33 +0000[diff] [blame]2209</div>
2210
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2211<!-- *********************************************************************** -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2212<h2><a name="constants">Constants</a></h2>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2213<!-- *********************************************************************** -->
2214
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2215<div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2216
2217<p>LLVM has several different basic types of constants. This section describes
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2218 them all and their syntax.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2219
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2220<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2221<h3>
2222 <a name="simpleconstants">Simple Constants</a>
2223</h3>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2224
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2225<div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2226
2227<dl>
2228 <dt><b>Boolean constants</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2229 <dd>The two strings '<tt>true</tt>' and '<tt>false</tt>' are both valid
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]2230 constants of the <tt><a href="#t_integer">i1</a></tt> type.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2231
2232 <dt><b>Integer constants</b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2233 <dd>Standard integers (such as '4') are constants of
2234 the <a href="#t_integer">integer</a> type. Negative numbers may be used
2235 with integer types.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2236
2237 <dt><b>Floating point constants</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2238 <dd>Floating point constants use standard decimal notation (e.g. 123.421),
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2239 exponential notation (e.g. 1.23421e+2), or a more precise hexadecimal
2240 notation (see below). The assembler requires the exact decimal value of a
2241 floating-point constant. For example, the assembler accepts 1.25 but
2242 rejects 1.3 because 1.3 is a repeating decimal in binary. Floating point
2243 constants must have a <a href="#t_floating">floating point</a> type. </dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2244
2245 <dt><b>Null pointer constants</b></dt>
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]2246 <dd>The identifier '<tt>null</tt>' is recognized as a null pointer constant
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2247 and must be of <a href="#t_pointer">pointer type</a>.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2248</dl>
2249
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2250<p>The one non-intuitive notation for constants is the hexadecimal form of
2251 floating point constants. For example, the form '<tt>double
2252 0x432ff973cafa8000</tt>' is equivalent to (but harder to read than)
2253 '<tt>double 4.5e+15</tt>'. The only time hexadecimal floating point
2254 constants are required (and the only time that they are generated by the
2255 disassembler) is when a floating point constant must be emitted but it cannot
2256 be represented as a decimal floating point number in a reasonable number of
2257 digits. For example, NaN's, infinities, and other special values are
2258 represented in their IEEE hexadecimal format so that assembly and disassembly
2259 do not cause any bits to change in the constants.</p>
2260
Dale Johannesenbd5e5a82009-02-11 22:14:51 +0000[diff] [blame]2261<p>When using the hexadecimal form, constants of types float and double are
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2262 represented using the 16-digit form shown above (which matches the IEEE754
2263 representation for double); float values must, however, be exactly
2264 representable as IEE754 single precision. Hexadecimal format is always used
2265 for long double, and there are three forms of long double. The 80-bit format
2266 used by x86 is represented as <tt>0xK</tt> followed by 20 hexadecimal digits.
2267 The 128-bit format used by PowerPC (two adjacent doubles) is represented
2268 by <tt>0xM</tt> followed by 32 hexadecimal digits. The IEEE 128-bit format
2269 is represented by <tt>0xL</tt> followed by 32 hexadecimal digits; no
2270 currently supported target uses this format. Long doubles will only work if
2271 they match the long double format on your target. All hexadecimal formats
2272 are big-endian (sign bit at the left).</p>
2273
Dale Johannesen21fe99b2010-10-01 00:48:59 +0000[diff] [blame]2274<p>There are no constants of type x86mmx.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2275</div>
2276
2277<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2278<h3>
Bill Wendlingd9fe2982009-07-20 02:32:41 +0000[diff] [blame]2279<a name="aggregateconstants"></a> <!-- old anchor -->
2280<a name="complexconstants">Complex Constants</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2281</h3>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2282
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2283<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2284
Chris Lattner70882792009-02-28 18:32:25 +0000[diff] [blame]2285<p>Complex constants are a (potentially recursive) combination of simple
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2286 constants and smaller complex constants.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2287
2288<dl>
2289 <dt><b>Structure constants</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2290 <dd>Structure constants are represented with notation similar to structure
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2291 type definitions (a comma separated list of elements, surrounded by braces
2292 (<tt>{}</tt>)). For example: "<tt>{ i32 4, float 17.0, i32* @G }</tt>",
2293 where "<tt>@G</tt>" is declared as "<tt>@G = external global i32</tt>".
2294 Structure constants must have <a href="#t_struct">structure type</a>, and
2295 the number and types of elements must match those specified by the
2296 type.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2297
2298 <dt><b>Array constants</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2299 <dd>Array constants are represented with notation similar to array type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2300 definitions (a comma separated list of elements, surrounded by square
2301 brackets (<tt>[]</tt>)). For example: "<tt>[ i32 42, i32 11, i32 74
2302 ]</tt>". Array constants must have <a href="#t_array">array type</a>, and
2303 the number and types of elements must match those specified by the
2304 type.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2305
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2306 <dt><b>Vector constants</b></dt>
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2307 <dd>Vector constants are represented with notation similar to vector type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2308 definitions (a comma separated list of elements, surrounded by
2309 less-than/greater-than's (<tt>&lt;&gt;</tt>)). For example: "<tt>&lt; i32
2310 42, i32 11, i32 74, i32 100 &gt;</tt>". Vector constants must
2311 have <a href="#t_vector">vector type</a>, and the number and types of
2312 elements must match those specified by the type.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2313
2314 <dt><b>Zero initialization</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2315 <dd>The string '<tt>zeroinitializer</tt>' can be used to zero initialize a
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]2316 value to zero of <em>any</em> type, including scalar and
2317 <a href="#t_aggregate">aggregate</a> types.
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2318 This is often used to avoid having to print large zero initializers
2319 (e.g. for large arrays) and is always exactly equivalent to using explicit
2320 zero initializers.</dd>
Nick Lewycky21cc4462009-04-04 07:22:01 +0000[diff] [blame]2321
2322 <dt><b>Metadata node</b></dt>
Nick Lewycky1e8c7a62009-05-30 16:08:30 +0000[diff] [blame]2323 <dd>A metadata node is a structure-like constant with
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2324 <a href="#t_metadata">metadata type</a>. For example: "<tt>metadata !{
2325 i32 0, metadata !"test" }</tt>". Unlike other constants that are meant to
2326 be interpreted as part of the instruction stream, metadata is a place to
2327 attach additional information such as debug info.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2328</dl>
2329
2330</div>
2331
2332<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2333<h3>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2334 <a name="globalconstants">Global Variable and Function Addresses</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2335</h3>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2336
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2337<div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2338
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2339<p>The addresses of <a href="#globalvars">global variables</a>
2340 and <a href="#functionstructure">functions</a> are always implicitly valid
2341 (link-time) constants. These constants are explicitly referenced when
2342 the <a href="#identifiers">identifier for the global</a> is used and always
2343 have <a href="#t_pointer">pointer</a> type. For example, the following is a
2344 legal LLVM file:</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2345
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2346<pre class="doc_code">
Chris Lattnera18a4242007-06-06 18:28:13 +0000[diff] [blame]2347@X = global i32 17
2348@Y = global i32 42
2349@Z = global [2 x i32*] [ i32* @X, i32* @Y ]
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2350</pre>
2351
2352</div>
2353
2354<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2355<h3>
2356 <a name="undefvalues">Undefined Values</a>
2357</h3>
2358
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2359<div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2360
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2361<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]2362 indicates that the user of the value may receive an unspecified bit-pattern.
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]2363 Undefined values may be of any type (other than '<tt>label</tt>'
2364 or '<tt>void</tt>') and be used anywhere a constant is permitted.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2365
Chris Lattnerc608cb12009-09-11 01:49:31 +0000[diff] [blame]2366<p>Undefined values are useful because they indicate to the compiler that the
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2367 program is well defined no matter what value is used. This gives the
2368 compiler more freedom to optimize. Here are some examples of (potentially
2369 surprising) transformations that are valid (in pseudo IR):</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2370
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2371
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2372<pre class="doc_code">
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2373 %A = add %X, undef
2374 %B = sub %X, undef
2375 %C = xor %X, undef
2376Safe:
2377 %A = undef
2378 %B = undef
2379 %C = undef
2380</pre>
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2381
2382<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]2383 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]2384
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2385<pre class="doc_code">
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2386 %A = or %X, undef
2387 %B = and %X, undef
2388Safe:
2389 %A = -1
2390 %B = 0
2391Unsafe:
2392 %A = undef
2393 %B = undef
2394</pre>
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2395
2396<p>These logical operations have bits that are not always affected by the input.
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]2397 For example, if <tt>%X</tt> has a zero bit, then the output of the
2398 '<tt>and</tt>' operation will always be a zero for that bit, no matter what
2399 the corresponding bit from the '<tt>undef</tt>' is. As such, it is unsafe to
2400 optimize or assume that the result of the '<tt>and</tt>' is '<tt>undef</tt>'.
2401 However, it is safe to assume that all bits of the '<tt>undef</tt>' could be
2402 0, and optimize the '<tt>and</tt>' to 0. Likewise, it is safe to assume that
2403 all the bits of the '<tt>undef</tt>' operand to the '<tt>or</tt>' could be
2404 set, allowing the '<tt>or</tt>' to be folded to -1.</p>
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2405
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2406<pre class="doc_code">
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2407 %A = select undef, %X, %Y
2408 %B = select undef, 42, %Y
2409 %C = select %X, %Y, undef
2410Safe:
2411 %A = %X (or %Y)
2412 %B = 42 (or %Y)
2413 %C = %Y
2414Unsafe:
2415 %A = undef
2416 %B = undef
2417 %C = undef
2418</pre>
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2419
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]2420<p>This set of examples shows that undefined '<tt>select</tt>' (and conditional
2421 branch) conditions can go <em>either way</em>, but they have to come from one
2422 of the two operands. In the <tt>%A</tt> example, if <tt>%X</tt> and
2423 <tt>%Y</tt> were both known to have a clear low bit, then <tt>%A</tt> would
2424 have to have a cleared low bit. However, in the <tt>%C</tt> example, the
2425 optimizer is allowed to assume that the '<tt>undef</tt>' operand could be the
2426 same as <tt>%Y</tt>, allowing the whole '<tt>select</tt>' to be
2427 eliminated.</p>
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2428
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2429<pre class="doc_code">
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2430 %A = xor undef, undef
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]2431
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2432 %B = undef
2433 %C = xor %B, %B
2434
2435 %D = undef
2436 %E = icmp lt %D, 4
2437 %F = icmp gte %D, 4
2438
2439Safe:
2440 %A = undef
2441 %B = undef
2442 %C = undef
2443 %D = undef
2444 %E = undef
2445 %F = undef
2446</pre>
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2447
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]2448<p>This example points out that two '<tt>undef</tt>' operands are not
2449 necessarily the same. This can be surprising to people (and also matches C
2450 semantics) where they assume that "<tt>X^X</tt>" is always zero, even
2451 if <tt>X</tt> is undefined. This isn't true for a number of reasons, but the
2452 short answer is that an '<tt>undef</tt>' "variable" can arbitrarily change
2453 its value over its "live range". This is true because the variable doesn't
2454 actually <em>have a live range</em>. Instead, the value is logically read
2455 from arbitrary registers that happen to be around when needed, so the value
2456 is not necessarily consistent over time. In fact, <tt>%A</tt> and <tt>%C</tt>
2457 need to have the same semantics or the core LLVM "replace all uses with"
2458 concept would not hold.</p>
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2459
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2460<pre class="doc_code">
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2461 %A = fdiv undef, %X
2462 %B = fdiv %X, undef
2463Safe:
2464 %A = undef
2465b: unreachable
2466</pre>
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2467
2468<p>These examples show the crucial difference between an <em>undefined
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]2469 value</em> and <em>undefined behavior</em>. An undefined value (like
2470 '<tt>undef</tt>') is allowed to have an arbitrary bit-pattern. This means that
2471 the <tt>%A</tt> operation can be constant folded to '<tt>undef</tt>', because
2472 the '<tt>undef</tt>' could be an SNaN, and <tt>fdiv</tt> is not (currently)
2473 defined on SNaN's. However, in the second example, we can make a more
2474 aggressive assumption: because the <tt>undef</tt> is allowed to be an
2475 arbitrary value, we are allowed to assume that it could be zero. Since a
2476 divide by zero has <em>undefined behavior</em>, we are allowed to assume that
2477 the operation does not execute at all. This allows us to delete the divide and
2478 all code after it. Because the undefined operation "can't happen", the
2479 optimizer can assume that it occurs in dead code.</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]2480
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2481<pre class="doc_code">
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2482a: store undef -> %X
2483b: store %X -> undef
2484Safe:
2485a: &lt;deleted&gt;
2486b: unreachable
2487</pre>
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2488
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]2489<p>These examples reiterate the <tt>fdiv</tt> example: a store <em>of</em> an
2490 undefined value can be assumed to not have any effect; we can assume that the
2491 value is overwritten with bits that happen to match what was already there.
2492 However, a store <em>to</em> an undefined location could clobber arbitrary
2493 memory, therefore, it has undefined behavior.</p>
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2494
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2495</div>
2496
2497<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2498<h3>
2499 <a name="trapvalues">Trap Values</a>
2500</h3>
2501
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2502<div>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]2503
Dan Gohmanc68ce062010-04-26 20:21:21 +0000[diff] [blame]2504<p>Trap values are similar to <a href="#undefvalues">undef values</a>, however
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]2505 instead of representing an unspecified bit pattern, they represent the
2506 fact that an instruction or constant expression which cannot evoke side
2507 effects has nevertheless detected a condition which results in undefined
Dan Gohmanc68ce062010-04-26 20:21:21 +0000[diff] [blame]2508 behavior.</p>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]2509
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2510<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]2511 only exist when produced by operations such as
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2512 <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]2513
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2514<p>Trap value behavior is defined in terms of value <i>dependence</i>:</p>
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2515
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2516<ul>
2517<li>Values other than <a href="#i_phi"><tt>phi</tt></a> nodes depend on
2518 their operands.</li>
2519
2520<li><a href="#i_phi"><tt>Phi</tt></a> nodes depend on the operand corresponding
2521 to their dynamic predecessor basic block.</li>
2522
2523<li>Function arguments depend on the corresponding actual argument values in
2524 the dynamic callers of their functions.</li>
2525
2526<li><a href="#i_call"><tt>Call</tt></a> instructions depend on the
2527 <a href="#i_ret"><tt>ret</tt></a> instructions that dynamically transfer
2528 control back to them.</li>
2529
Dan Gohmanb5328162010-05-03 14:55:22 +0000[diff] [blame]2530<li><a href="#i_invoke"><tt>Invoke</tt></a> instructions depend on the
2531 <a href="#i_ret"><tt>ret</tt></a>, <a href="#i_unwind"><tt>unwind</tt></a>,
2532 or exception-throwing call instructions that dynamically transfer control
2533 back to them.</li>
2534
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2535<li>Non-volatile loads and stores depend on the most recent stores to all of the
2536 referenced memory addresses, following the order in the IR
2537 (including loads and stores implied by intrinsics such as
2538 <a href="#int_memcpy"><tt>@llvm.memcpy</tt></a>.)</li>
2539
Dan Gohman7c24ff12010-05-03 14:59:34 +0000[diff] [blame]2540<!-- TODO: In the case of multiple threads, this only applies if the store
2541 "happens-before" the load or store. -->
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2542
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2543<!-- TODO: floating-point exception state -->
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2544
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2545<li>An instruction with externally visible side effects depends on the most
2546 recent preceding instruction with externally visible side effects, following
Dan Gohmanff70fe42010-07-06 15:26:33 +0000[diff] [blame]2547 the order in the IR. (This includes
2548 <a href="#volatile">volatile operations</a>.)</li>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]2549
Dan Gohmanb5328162010-05-03 14:55:22 +0000[diff] [blame]2550<li>An instruction <i>control-depends</i> on a
2551 <a href="#terminators">terminator instruction</a>
2552 if the terminator instruction has multiple successors and the instruction
2553 is always executed when control transfers to one of the successors, and
Chris Lattner7a2bdde2011-04-15 05:18:47 +0000[diff] [blame]2554 may not be executed when control is transferred to another.</li>
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2555
Dan Gohmanca4cac42011-04-12 23:05:59 +0000[diff] [blame]2556<li>Additionally, an instruction also <i>control-depends</i> on a terminator
2557 instruction if the set of instructions it otherwise depends on would be
Chris Lattner7a2bdde2011-04-15 05:18:47 +0000[diff] [blame]2558 different if the terminator had transferred control to a different
Dan Gohmanca4cac42011-04-12 23:05:59 +0000[diff] [blame]2559 successor.</li>
2560
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2561<li>Dependence is transitive.</li>
2562
2563</ul>
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2564
2565<p>Whenever a trap value is generated, all values which depend on it evaluate
Lang Hames87d5cb82011-10-13 23:04:49 +0000[diff] [blame]2566 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]2567 operand with a trap value were undef. If they have externally-visible side
2568 effects, the behavior is undefined.</p>
2569
2570<p>Here are some examples:</p>
Dan Gohmanc30f6e12010-04-26 20:54:53 +0000[diff] [blame]2571
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2572<pre class="doc_code">
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2573entry:
2574 %trap = sub nuw i32 0, 1 ; Results in a trap value.
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2575 %still_trap = and i32 %trap, 0 ; Whereas (and i32 undef, 0) would return 0.
2576 %trap_yet_again = getelementptr i32* @h, i32 %still_trap
2577 store i32 0, i32* %trap_yet_again ; undefined behavior
2578
2579 store i32 %trap, i32* @g ; Trap value conceptually stored to memory.
2580 %trap2 = load i32* @g ; Returns a trap value, not just undef.
2581
2582 volatile store i32 %trap, i32* @g ; External observation; undefined behavior.
2583
2584 %narrowaddr = bitcast i32* @g to i16*
2585 %wideaddr = bitcast i32* @g to i64*
Nick Lewycky64f9fb12011-05-16 19:29:30 +0000[diff] [blame]2586 %trap3 = load i16* %narrowaddr ; Returns a trap value.
2587 %trap4 = load i64* %wideaddr ; Returns a trap value.
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2588
Nick Lewycky64f9fb12011-05-16 19:29:30 +0000[diff] [blame]2589 %cmp = icmp slt i32 %trap, 0 ; Returns a trap value.
2590 br i1 %cmp, label %true, label %end ; Branch to either destination.
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2591
2592true:
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2593 volatile store i32 0, i32* @g ; This is control-dependent on %cmp, so
2594 ; it has undefined behavior.
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2595 br label %end
2596
2597end:
2598 %p = phi i32 [ 0, %entry ], [ 1, %true ]
2599 ; Both edges into this PHI are
2600 ; control-dependent on %cmp, so this
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2601 ; always results in a trap value.
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2602
Dan Gohmanca4cac42011-04-12 23:05:59 +0000[diff] [blame]2603 volatile store i32 0, i32* @g ; This would depend on the store in %true
2604 ; if %cmp is true, or the store in %entry
2605 ; otherwise, so this is undefined behavior.
2606
Nick Lewycky64f9fb12011-05-16 19:29:30 +0000[diff] [blame]2607 br i1 %cmp, label %second_true, label %second_end
Dan Gohmanca4cac42011-04-12 23:05:59 +0000[diff] [blame]2608 ; The same branch again, but this time the
2609 ; true block doesn't have side effects.
2610
2611second_true:
2612 ; No side effects!
Nick Lewycky64f9fb12011-05-16 19:29:30 +0000[diff] [blame]2613 ret void
Dan Gohmanca4cac42011-04-12 23:05:59 +0000[diff] [blame]2614
2615second_end:
2616 volatile store i32 0, i32* @g ; This time, the instruction always depends
2617 ; on the store in %end. Also, it is
2618 ; control-equivalent to %end, so this is
Nick Lewycky64f9fb12011-05-16 19:29:30 +0000[diff] [blame]2619 ; well-defined (again, ignoring earlier
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2620 ; undefined behavior in this example).
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2621</pre>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]2622
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]2623</div>
2624
2625<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2626<h3>
2627 <a name="blockaddress">Addresses of Basic Blocks</a>
2628</h3>
2629
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2630<div>
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]2631
Chris Lattnercdfc9402009-11-01 01:27:45 +0000[diff] [blame]2632<p><b><tt>blockaddress(@function, %block)</tt></b></p>
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]2633
2634<p>The '<tt>blockaddress</tt>' constant computes the address of the specified
Chris Lattner2dfdf2a2009-10-27 21:49:40 +0000[diff] [blame]2635 basic block in the specified function, and always has an i8* type. Taking
Chris Lattnercdfc9402009-11-01 01:27:45 +0000[diff] [blame]2636 the address of the entry block is illegal.</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]2637
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]2638<p>This value only has defined behavior when used as an operand to the
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]2639 '<a href="#i_indirectbr"><tt>indirectbr</tt></a>' instruction, or for
2640 comparisons against null. Pointer equality tests between labels addresses
2641 results in undefined behavior &mdash; though, again, comparison against null
2642 is ok, and no label is equal to the null pointer. This may be passed around
2643 as an opaque pointer sized value as long as the bits are not inspected. This
2644 allows <tt>ptrtoint</tt> and arithmetic to be performed on these values so
2645 long as the original value is reconstituted before the <tt>indirectbr</tt>
2646 instruction.</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]2647
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]2648<p>Finally, some targets may provide defined semantics when using the value as
2649 the operand to an inline assembly, but that is target specific.</p>
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]2650
2651</div>
2652
2653
2654<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2655<h3>
2656 <a name="constantexprs">Constant Expressions</a>
2657</h3>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2658
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2659<div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2660
2661<p>Constant expressions are used to allow expressions involving other constants
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2662 to be used as constants. Constant expressions may be of
2663 any <a href="#t_firstclass">first class</a> type and may involve any LLVM
2664 operation that does not have side effects (e.g. load and call are not
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]2665 supported). The following is the syntax for constant expressions:</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2666
2667<dl>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2668 <dt><b><tt>trunc (CST to TYPE)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2669 <dd>Truncate a constant to another type. The bit size of CST must be larger
2670 than the bit size of TYPE. Both types must be integers.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2671
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2672 <dt><b><tt>zext (CST to TYPE)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2673 <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]2674 smaller than the bit size of TYPE. Both types must be integers.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2675
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2676 <dt><b><tt>sext (CST to TYPE)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2677 <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]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>fptrunc (CST to TYPE)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2681 <dd>Truncate a floating point constant to another floating point type. The
2682 size of CST must be larger than the size of TYPE. Both types must be
2683 floating point.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2684
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2685 <dt><b><tt>fpext (CST to TYPE)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2686 <dd>Floating point extend a constant to another type. The size of CST must be
2687 smaller or equal to the size of TYPE. Both types must be floating
2688 point.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2689
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2690 <dt><b><tt>fptoui (CST to TYPE)</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2691 <dd>Convert a floating point constant to the corresponding unsigned integer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2692 constant. TYPE must be a scalar or vector integer type. CST must be of
2693 scalar or vector floating point type. Both CST and TYPE must be scalars,
2694 or vectors of the same number of elements. If the value won't fit in the
2695 integer type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2696
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2697 <dt><b><tt>fptosi (CST to TYPE)</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2698 <dd>Convert a floating point constant to the corresponding signed integer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2699 constant. TYPE must be a scalar or vector integer type. CST must be of
2700 scalar or vector floating point type. Both CST and TYPE must be scalars,
2701 or vectors of the same number of elements. If the value won't fit in the
2702 integer type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2703
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2704 <dt><b><tt>uitofp (CST to TYPE)</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2705 <dd>Convert an unsigned integer constant to the corresponding floating point
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2706 constant. TYPE must be a scalar or vector floating point type. CST must be
2707 of scalar or vector integer type. Both CST and TYPE must be scalars, or
2708 vectors of the same number of elements. If the value won't fit in the
2709 floating point type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2710
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2711 <dt><b><tt>sitofp (CST to TYPE)</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2712 <dd>Convert a signed integer constant to the corresponding floating point
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2713 constant. TYPE must be a scalar or vector floating point type. CST must be
2714 of scalar or vector integer type. Both CST and TYPE must be scalars, or
2715 vectors of the same number of elements. If the value won't fit in the
2716 floating point type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2717
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2718 <dt><b><tt>ptrtoint (CST to TYPE)</tt></b></dt>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]2719 <dd>Convert a pointer typed constant to the corresponding integer constant
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2720 <tt>TYPE</tt> must be an integer type. <tt>CST</tt> must be of pointer
2721 type. The <tt>CST</tt> value is zero extended, truncated, or unchanged to
2722 make it fit in <tt>TYPE</tt>.</dd>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]2723
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2724 <dt><b><tt>inttoptr (CST to TYPE)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2725 <dd>Convert a integer constant to a pointer constant. TYPE must be a pointer
2726 type. CST must be of integer type. The CST value is zero extended,
2727 truncated, or unchanged to make it fit in a pointer size. This one is
2728 <i>really</i> dangerous!</dd>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]2729
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2730 <dt><b><tt>bitcast (CST to TYPE)</tt></b></dt>
Chris Lattner03bbad62009-02-28 18:27:03 +0000[diff] [blame]2731 <dd>Convert a constant, CST, to another TYPE. The constraints of the operands
2732 are the same as those for the <a href="#i_bitcast">bitcast
2733 instruction</a>.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2734
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2735 <dt><b><tt>getelementptr (CSTPTR, IDX0, IDX1, ...)</tt></b></dt>
2736 <dt><b><tt>getelementptr inbounds (CSTPTR, IDX0, IDX1, ...)</tt></b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2737 <dd>Perform the <a href="#i_getelementptr">getelementptr operation</a> on
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2738 constants. As with the <a href="#i_getelementptr">getelementptr</a>
2739 instruction, the index list may have zero or more indexes, which are
2740 required to make sense for the type of "CSTPTR".</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2741
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2742 <dt><b><tt>select (COND, VAL1, VAL2)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2743 <dd>Perform the <a href="#i_select">select operation</a> on constants.</dd>
Reid Spencer01c42592006-12-04 19:23:19 +0000[diff] [blame]2744
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2745 <dt><b><tt>icmp COND (VAL1, VAL2)</tt></b></dt>
Reid Spencer01c42592006-12-04 19:23:19 +0000[diff] [blame]2746 <dd>Performs the <a href="#i_icmp">icmp operation</a> on constants.</dd>
2747
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2748 <dt><b><tt>fcmp COND (VAL1, VAL2)</tt></b></dt>
Reid Spencer01c42592006-12-04 19:23:19 +0000[diff] [blame]2749 <dd>Performs the <a href="#i_fcmp">fcmp operation</a> on constants.</dd>
Robert Bocchino9fbe1452006-01-10 19:31:34 +0000[diff] [blame]2750
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2751 <dt><b><tt>extractelement (VAL, IDX)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2752 <dd>Perform the <a href="#i_extractelement">extractelement operation</a> on
2753 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>insertelement (VAL, ELT, IDX)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2756 <dd>Perform the <a href="#i_insertelement">insertelement operation</a> on
2757 constants.</dd>
Chris Lattnerc1989542006-04-08 00:13:41 +0000[diff] [blame]2758
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2759 <dt><b><tt>shufflevector (VEC1, VEC2, IDXMASK)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2760 <dd>Perform the <a href="#i_shufflevector">shufflevector operation</a> on
2761 constants.</dd>
Chris Lattnerc1989542006-04-08 00:13:41 +0000[diff] [blame]2762
Nick Lewycky9e130ce2010-05-29 06:44:15 +0000[diff] [blame]2763 <dt><b><tt>extractvalue (VAL, IDX0, IDX1, ...)</tt></b></dt>
2764 <dd>Perform the <a href="#i_extractvalue">extractvalue operation</a> on
2765 constants. The index list is interpreted in a similar manner as indices in
2766 a '<a href="#i_getelementptr">getelementptr</a>' operation. At least one
2767 index value must be specified.</dd>
2768
2769 <dt><b><tt>insertvalue (VAL, ELT, IDX0, IDX1, ...)</tt></b></dt>
2770 <dd>Perform the <a href="#i_insertvalue">insertvalue operation</a> on
2771 constants. The index list is interpreted in a similar manner as indices in
2772 a '<a href="#i_getelementptr">getelementptr</a>' operation. At least one
2773 index value must be specified.</dd>
2774
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2775 <dt><b><tt>OPCODE (LHS, RHS)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2776 <dd>Perform the specified operation of the LHS and RHS constants. OPCODE may
2777 be any of the <a href="#binaryops">binary</a>
2778 or <a href="#bitwiseops">bitwise binary</a> operations. The constraints
2779 on operands are the same as those for the corresponding instruction
2780 (e.g. no bitwise operations on floating point values are allowed).</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2781</dl>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2782
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2783</div>
Chris Lattner9ee5d222004-03-08 16:49:10 +0000[diff] [blame]2784
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2785</div>
2786
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2787<!-- *********************************************************************** -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2788<h2><a name="othervalues">Other Values</a></h2>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2789<!-- *********************************************************************** -->
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2790<div>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2791<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2792<h3>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2793<a name="inlineasm">Inline Assembler Expressions</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2794</h3>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2795
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2796<div>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2797
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2798<p>LLVM supports inline assembler expressions (as opposed
2799 to <a href="#moduleasm"> Module-Level Inline Assembly</a>) through the use of
2800 a special value. This value represents the inline assembler as a string
2801 (containing the instructions to emit), a list of operand constraints (stored
Dale Johannesen09fed252009-10-13 21:56:55 +0000[diff] [blame]2802 as a string), a flag that indicates whether or not the inline asm
Dale Johannesen8ba2d5b2009-10-21 23:28:00 +0000[diff] [blame]2803 expression has side effects, and a flag indicating whether the function
2804 containing the asm needs to align its stack conservatively. An example
2805 inline assembler expression is:</p>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2806
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2807<pre class="doc_code">
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2808i32 (i32) asm "bswap $0", "=r,r"
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2809</pre>
2810
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2811<p>Inline assembler expressions may <b>only</b> be used as the callee operand of
2812 a <a href="#i_call"><tt>call</tt> instruction</a>. Thus, typically we
2813 have:</p>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2814
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2815<pre class="doc_code">
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2816%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]2817</pre>
2818
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2819<p>Inline asms with side effects not visible in the constraint list must be
2820 marked as having side effects. This is done through the use of the
2821 '<tt>sideeffect</tt>' keyword, like so:</p>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2822
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2823<pre class="doc_code">
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2824call void asm sideeffect "eieio", ""()
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2825</pre>
2826
Dale Johannesen8ba2d5b2009-10-21 23:28:00 +0000[diff] [blame]2827<p>In some cases inline asms will contain code that will not work unless the
2828 stack is aligned in some way, such as calls or SSE instructions on x86,
2829 yet will not contain code that does that alignment within the asm.
2830 The compiler should make conservative assumptions about what the asm might
2831 contain and should generate its usual stack alignment code in the prologue
2832 if the '<tt>alignstack</tt>' keyword is present:</p>
Dale Johannesen09fed252009-10-13 21:56:55 +0000[diff] [blame]2833
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2834<pre class="doc_code">
Dale Johannesen8ba2d5b2009-10-21 23:28:00 +0000[diff] [blame]2835call void asm alignstack "eieio", ""()
Dale Johannesen09fed252009-10-13 21:56:55 +0000[diff] [blame]2836</pre>
Dale Johannesen09fed252009-10-13 21:56:55 +0000[diff] [blame]2837
2838<p>If both keywords appear the '<tt>sideeffect</tt>' keyword must come
2839 first.</p>
2840
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2841<p>TODO: The format of the asm and constraints string still need to be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2842 documented here. Constraints on what can be done (e.g. duplication, moving,
2843 etc need to be documented). This is probably best done by reference to
2844 another document that covers inline asm from a holistic perspective.</p>
Chris Lattnercf9a4152010-04-07 05:38:05 +0000[diff] [blame]2845
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2846<h4>
Chris Lattnercf9a4152010-04-07 05:38:05 +0000[diff] [blame]2847<a name="inlineasm_md">Inline Asm Metadata</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2848</h4>
Chris Lattnercf9a4152010-04-07 05:38:05 +0000[diff] [blame]2849
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2850<div>
Chris Lattnercf9a4152010-04-07 05:38:05 +0000[diff] [blame]2851
2852<p>The call instructions that wrap inline asm nodes may have a "!srcloc" MDNode
Chris Lattnerce1b9ad2010-11-17 08:20:42 +0000[diff] [blame]2853 attached to it that contains a list of constant integers. If present, the
2854 code generator will use the integer as the location cookie value when report
Chris Lattnercf9a4152010-04-07 05:38:05 +0000[diff] [blame]2855 errors through the LLVMContext error reporting mechanisms. This allows a
Dan Gohman1c70c002010-04-28 00:36:01 +0000[diff] [blame]2856 front-end to correlate backend errors that occur with inline asm back to the
Chris Lattnercf9a4152010-04-07 05:38:05 +0000[diff] [blame]2857 source code that produced it. For example:</p>
2858
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2859<pre class="doc_code">
Chris Lattnercf9a4152010-04-07 05:38:05 +0000[diff] [blame]2860call void asm sideeffect "something bad", ""()<b>, !srcloc !42</b>
2861...
2862!42 = !{ i32 1234567 }
2863</pre>
Chris Lattnercf9a4152010-04-07 05:38:05 +0000[diff] [blame]2864
2865<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]2866 IR. If the MDNode contains multiple constants, the code generator will use
2867 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]2868
2869</div>
2870
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2871</div>
2872
Chris Lattnere6a5ddd2010-01-15 21:50:19 +0000[diff] [blame]2873<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2874<h3>
2875 <a name="metadata">Metadata Nodes and Metadata Strings</a>
2876</h3>
Chris Lattnere6a5ddd2010-01-15 21:50:19 +0000[diff] [blame]2877
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2878<div>
Chris Lattnere6a5ddd2010-01-15 21:50:19 +0000[diff] [blame]2879
2880<p>LLVM IR allows metadata to be attached to instructions in the program that
2881 can convey extra information about the code to the optimizers and code
2882 generator. One example application of metadata is source-level debug
2883 information. There are two metadata primitives: strings and nodes. All
2884 metadata has the <tt>metadata</tt> type and is identified in syntax by a
2885 preceding exclamation point ('<tt>!</tt>').</p>
2886
2887<p>A metadata string is a string surrounded by double quotes. It can contain
2888 any character by escaping non-printable characters with "\xx" where "xx" is
2889 the two digit hex code. For example: "<tt>!"test\00"</tt>".</p>
2890
2891<p>Metadata nodes are represented with notation similar to structure constants
2892 (a comma separated list of elements, surrounded by braces and preceded by an
2893 exclamation point). For example: "<tt>!{ metadata !"test\00", i32
2894 10}</tt>". Metadata nodes can have any values as their operand.</p>
2895
2896<p>A <a href="#namedmetadatastructure">named metadata</a> is a collection of
2897 metadata nodes, which can be looked up in the module symbol table. For
2898 example: "<tt>!foo = metadata !{!4, !3}</tt>".
2899
Devang Patele1d50cd2010-03-04 23:44:48 +0000[diff] [blame]2900<p>Metadata can be used as function arguments. Here <tt>llvm.dbg.value</tt>
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2901 function is using two metadata arguments.</p>
Devang Patele1d50cd2010-03-04 23:44:48 +0000[diff] [blame]2902
Bill Wendling9ff5de92011-03-02 02:17:11 +0000[diff] [blame]2903<div class="doc_code">
2904<pre>
2905call void @llvm.dbg.value(metadata !24, i64 0, metadata !25)
2906</pre>
2907</div>
Devang Patele1d50cd2010-03-04 23:44:48 +0000[diff] [blame]2908
2909<p>Metadata can be attached with an instruction. Here metadata <tt>!21</tt> is
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2910 attached with <tt>add</tt> instruction using <tt>!dbg</tt> identifier.</p>
Devang Patele1d50cd2010-03-04 23:44:48 +0000[diff] [blame]2911
Bill Wendling9ff5de92011-03-02 02:17:11 +0000[diff] [blame]2912<div class="doc_code">
2913<pre>
2914%indvar.next = add i64 %indvar, 1, !dbg !21
2915</pre>
2916</div>
2917
Chris Lattnere6a5ddd2010-01-15 21:50:19 +0000[diff] [blame]2918</div>
2919
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2920</div>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]2921
2922<!-- *********************************************************************** -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2923<h2>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]2924 <a name="intrinsic_globals">Intrinsic Global Variables</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2925</h2>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]2926<!-- *********************************************************************** -->
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2927<div>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]2928<p>LLVM has a number of "magic" global variables that contain data that affect
2929code generation or other IR semantics. These are documented here. All globals
Chris Lattner401e10c2009-07-20 06:14:25 +0000[diff] [blame]2930of this sort should have a section specified as "<tt>llvm.metadata</tt>". This
2931section and all globals that start with "<tt>llvm.</tt>" are reserved for use
2932by LLVM.</p>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]2933
2934<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2935<h3>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]2936<a name="intg_used">The '<tt>llvm.used</tt>' Global Variable</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2937</h3>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]2938
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2939<div>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]2940
2941<p>The <tt>@llvm.used</tt> global is an array with i8* element type which has <a
2942href="#linkage_appending">appending linkage</a>. This array contains a list of
2943pointers to global variables and functions which may optionally have a pointer
2944cast formed of bitcast or getelementptr. For example, a legal use of it is:</p>
2945
2946<pre>
2947 @X = global i8 4
2948 @Y = global i32 123
2949
2950 @llvm.used = appending global [2 x i8*] [
2951 i8* @X,
2952 i8* bitcast (i32* @Y to i8*)
2953 ], section "llvm.metadata"
2954</pre>
2955
2956<p>If a global variable appears in the <tt>@llvm.used</tt> list, then the
2957compiler, assembler, and linker are required to treat the symbol as if there is
2958a reference to the global that it cannot see. For example, if a variable has
2959internal linkage and no references other than that from the <tt>@llvm.used</tt>
2960list, it cannot be deleted. This is commonly used to represent references from
2961inline asms and other things the compiler cannot "see", and corresponds to
2962"attribute((used))" in GNU C.</p>
2963
2964<p>On some targets, the code generator must emit a directive to the assembler or
2965object file to prevent the assembler and linker from molesting the symbol.</p>
2966
2967</div>
2968
2969<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2970<h3>
2971 <a name="intg_compiler_used">
2972 The '<tt>llvm.compiler.used</tt>' Global Variable
2973 </a>
2974</h3>
Chris Lattner401e10c2009-07-20 06:14:25 +0000[diff] [blame]2975
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2976<div>
Chris Lattner401e10c2009-07-20 06:14:25 +0000[diff] [blame]2977
2978<p>The <tt>@llvm.compiler.used</tt> directive is the same as the
2979<tt>@llvm.used</tt> directive, except that it only prevents the compiler from
2980touching the symbol. On targets that support it, this allows an intelligent
2981linker to optimize references to the symbol without being impeded as it would be
2982by <tt>@llvm.used</tt>.</p>
2983
2984<p>This is a rare construct that should only be used in rare circumstances, and
2985should not be exposed to source languages.</p>
2986
2987</div>
2988
2989<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2990<h3>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]2991<a name="intg_global_ctors">The '<tt>llvm.global_ctors</tt>' Global Variable</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2992</h3>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]2993
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2994<div>
David Chisnalle31e9962010-04-30 19:23:49 +0000[diff] [blame]2995<pre>
2996%0 = type { i32, void ()* }
David Chisnall27195a52010-04-30 19:27:35 +0000[diff] [blame]2997@llvm.global_ctors = appending global [1 x %0] [%0 { i32 65535, void ()* @ctor }]
David Chisnalle31e9962010-04-30 19:23:49 +0000[diff] [blame]2998</pre>
2999<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.
3000</p>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3001
3002</div>
3003
3004<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3005<h3>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3006<a name="intg_global_dtors">The '<tt>llvm.global_dtors</tt>' Global Variable</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3007</h3>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3008
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3009<div>
David Chisnalle31e9962010-04-30 19:23:49 +0000[diff] [blame]3010<pre>
3011%0 = type { i32, void ()* }
David Chisnall27195a52010-04-30 19:27:35 +0000[diff] [blame]3012@llvm.global_dtors = appending global [1 x %0] [%0 { i32 65535, void ()* @dtor }]
David Chisnalle31e9962010-04-30 19:23:49 +0000[diff] [blame]3013</pre>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3014
David Chisnalle31e9962010-04-30 19:23:49 +0000[diff] [blame]3015<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.
3016</p>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3017
3018</div>
3019
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3020</div>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3021
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]3022<!-- *********************************************************************** -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3023<h2><a name="instref">Instruction Reference</a></h2>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3024<!-- *********************************************************************** -->
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]3025
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3026<div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]3027
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3028<p>The LLVM instruction set consists of several different classifications of
3029 instructions: <a href="#terminators">terminator
3030 instructions</a>, <a href="#binaryops">binary instructions</a>,
3031 <a href="#bitwiseops">bitwise binary instructions</a>,
3032 <a href="#memoryops">memory instructions</a>, and
3033 <a href="#otherops">other instructions</a>.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]3034
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3035<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3036<h3>
3037 <a name="terminators">Terminator Instructions</a>
3038</h3>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]3039
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3040<div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]3041
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3042<p>As mentioned <a href="#functionstructure">previously</a>, every basic block
3043 in a program ends with a "Terminator" instruction, which indicates which
3044 block should be executed after the current block is finished. These
3045 terminator instructions typically yield a '<tt>void</tt>' value: they produce
3046 control flow, not values (the one exception being the
3047 '<a href="#i_invoke"><tt>invoke</tt></a>' instruction).</p>
3048
Chris Lattner6445ecb2011-08-02 20:29:13 +0000[diff] [blame]3049<p>The terminator instructions are:
3050 '<a href="#i_ret"><tt>ret</tt></a>',
3051 '<a href="#i_br"><tt>br</tt></a>',
3052 '<a href="#i_switch"><tt>switch</tt></a>',
3053 '<a href="#i_indirectbr"><tt>indirectbr</tt></a>',
3054 '<a href="#i_invoke"><tt>invoke</tt></a>',
3055 '<a href="#i_unwind"><tt>unwind</tt></a>',
3056 '<a href="#i_resume"><tt>resume</tt></a>', and
3057 '<a href="#i_unreachable"><tt>unreachable</tt></a>'.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]3058
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3059<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3060<h4>
3061 <a name="i_ret">'<tt>ret</tt>' Instruction</a>
3062</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3063
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3064<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3065
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3066<h5>Syntax:</h5>
Dan Gohmanb1e6b962008-10-04 19:00:07 +0000[diff] [blame]3067<pre>
3068 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]3069 ret void <i>; Return from void function</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3070</pre>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]3071
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3072<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3073<p>The '<tt>ret</tt>' instruction is used to return control flow (and optionally
3074 a value) from a function back to the caller.</p>
3075
3076<p>There are two forms of the '<tt>ret</tt>' instruction: one that returns a
3077 value and then causes control flow, and one that just causes control flow to
3078 occur.</p>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]3079
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3080<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3081<p>The '<tt>ret</tt>' instruction optionally accepts a single argument, the
3082 return value. The type of the return value must be a
3083 '<a href="#t_firstclass">first class</a>' type.</p>
Dan Gohmanb1e6b962008-10-04 19:00:07 +0000[diff] [blame]3084
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3085<p>A function is not <a href="#wellformed">well formed</a> if it it has a
3086 non-void return type and contains a '<tt>ret</tt>' instruction with no return
3087 value or a return value with a type that does not match its type, or if it
3088 has a void return type and contains a '<tt>ret</tt>' instruction with a
3089 return value.</p>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]3090
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3091<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3092<p>When the '<tt>ret</tt>' instruction is executed, control flow returns back to
3093 the calling function's context. If the caller is a
3094 "<a href="#i_call"><tt>call</tt></a>" instruction, execution continues at the
3095 instruction after the call. If the caller was an
3096 "<a href="#i_invoke"><tt>invoke</tt></a>" instruction, execution continues at
3097 the beginning of the "normal" destination block. If the instruction returns
3098 a value, that value shall set the call or invoke instruction's return
3099 value.</p>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]3100
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3101<h5>Example:</h5>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]3102<pre>
3103 ret i32 5 <i>; Return an integer value of 5</i>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]3104 ret void <i>; Return from a void function</i>
Bill Wendling0a4bbbf2009-02-28 22:12:54 +0000[diff] [blame]3105 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]3106</pre>
Dan Gohmanf3e60bd2009-01-12 23:12:39 +0000[diff] [blame]3107
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3108</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3109<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3110<h4>
3111 <a name="i_br">'<tt>br</tt>' Instruction</a>
3112</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3113
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3114<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3115
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3116<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3117<pre>
Bill Wendlingb3aa4712011-07-26 10:41:15 +0000[diff] [blame]3118 br i1 &lt;cond&gt;, label &lt;iftrue&gt;, label &lt;iffalse&gt;
3119 br label &lt;dest&gt; <i>; Unconditional branch</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3120</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3121
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3122<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3123<p>The '<tt>br</tt>' instruction is used to cause control flow to transfer to a
3124 different basic block in the current function. There are two forms of this
3125 instruction, corresponding to a conditional branch and an unconditional
3126 branch.</p>
3127
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3128<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3129<p>The conditional branch form of the '<tt>br</tt>' instruction takes a single
3130 '<tt>i1</tt>' value and two '<tt>label</tt>' values. The unconditional form
3131 of the '<tt>br</tt>' instruction takes a single '<tt>label</tt>' value as a
3132 target.</p>
3133
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3134<h5>Semantics:</h5>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3135<p>Upon execution of a conditional '<tt>br</tt>' instruction, the '<tt>i1</tt>'
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3136 argument is evaluated. If the value is <tt>true</tt>, control flows to the
3137 '<tt>iftrue</tt>' <tt>label</tt> argument. If "cond" is <tt>false</tt>,
3138 control flows to the '<tt>iffalse</tt>' <tt>label</tt> argument.</p>
3139
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3140<h5>Example:</h5>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]3141<pre>
3142Test:
3143 %cond = <a href="#i_icmp">icmp</a> eq i32 %a, %b
3144 br i1 %cond, label %IfEqual, label %IfUnequal
3145IfEqual:
3146 <a href="#i_ret">ret</a> i32 1
3147IfUnequal:
3148 <a href="#i_ret">ret</a> i32 0
3149</pre>
3150
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3151</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3152
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3153<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3154<h4>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3155 <a name="i_switch">'<tt>switch</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3156</h4>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3157
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3158<div>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3159
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3160<h5>Syntax:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3161<pre>
3162 switch &lt;intty&gt; &lt;value&gt;, label &lt;defaultdest&gt; [ &lt;intty&gt; &lt;val&gt;, label &lt;dest&gt; ... ]
3163</pre>
3164
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3165<h5>Overview:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3166<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]3167 several different places. It is a generalization of the '<tt>br</tt>'
3168 instruction, allowing a branch to occur to one of many possible
3169 destinations.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3170
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3171<h5>Arguments:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3172<p>The '<tt>switch</tt>' instruction uses three parameters: an integer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3173 comparison value '<tt>value</tt>', a default '<tt>label</tt>' destination,
3174 and an array of pairs of comparison value constants and '<tt>label</tt>'s.
3175 The table is not allowed to contain duplicate constant entries.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3176
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3177<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3178<p>The <tt>switch</tt> instruction specifies a table of values and
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3179 destinations. When the '<tt>switch</tt>' instruction is executed, this table
3180 is searched for the given value. If the value is found, control flow is
Benjamin Kramer8040cd32009-10-12 14:46:08 +0000[diff] [blame]3181 transferred to the corresponding destination; otherwise, control flow is
3182 transferred to the default destination.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3183
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3184<h5>Implementation:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3185<p>Depending on properties of the target machine and the particular
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3186 <tt>switch</tt> instruction, this instruction may be code generated in
3187 different ways. For example, it could be generated as a series of chained
3188 conditional branches or with a lookup table.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3189
3190<h5>Example:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3191<pre>
3192 <i>; Emulate a conditional br instruction</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3193 %Val = <a href="#i_zext">zext</a> i1 %value to i32
Dan Gohman2a08c532009-01-04 23:44:43 +0000[diff] [blame]3194 switch i32 %Val, label %truedest [ i32 0, label %falsedest ]
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3195
3196 <i>; Emulate an unconditional br instruction</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3197 switch i32 0, label %dest [ ]
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3198
3199 <i>; Implement a jump table:</i>
Dan Gohman2a08c532009-01-04 23:44:43 +0000[diff] [blame]3200 switch i32 %val, label %otherwise [ i32 0, label %onzero
3201 i32 1, label %onone
3202 i32 2, label %ontwo ]
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3203</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3204
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3205</div>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3206
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]3207
3208<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3209<h4>
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]3210 <a name="i_indirectbr">'<tt>indirectbr</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3211</h4>
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]3212
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3213<div>
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]3214
3215<h5>Syntax:</h5>
3216<pre>
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]3217 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]3218</pre>
3219
3220<h5>Overview:</h5>
3221
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]3222<p>The '<tt>indirectbr</tt>' instruction implements an indirect branch to a label
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]3223 within the current function, whose address is specified by
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]3224 "<tt>address</tt>". Address must be derived from a <a
3225 href="#blockaddress">blockaddress</a> constant.</p>
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]3226
3227<h5>Arguments:</h5>
3228
3229<p>The '<tt>address</tt>' argument is the address of the label to jump to. The
3230 rest of the arguments indicate the full set of possible destinations that the
3231 address may point to. Blocks are allowed to occur multiple times in the
3232 destination list, though this isn't particularly useful.</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3233
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]3234<p>This destination list is required so that dataflow analysis has an accurate
3235 understanding of the CFG.</p>
3236
3237<h5>Semantics:</h5>
3238
3239<p>Control transfers to the block specified in the address argument. All
3240 possible destination blocks must be listed in the label list, otherwise this
3241 instruction has undefined behavior. This implies that jumps to labels
3242 defined in other functions have undefined behavior as well.</p>
3243
3244<h5>Implementation:</h5>
3245
3246<p>This is typically implemented with a jump through a register.</p>
3247
3248<h5>Example:</h5>
3249<pre>
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]3250 indirectbr i8* %Addr, [ label %bb1, label %bb2, label %bb3 ]
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]3251</pre>
3252
3253</div>
3254
3255
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3256<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3257<h4>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3258 <a name="i_invoke">'<tt>invoke</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3259</h4>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3260
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3261<div>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3262
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3263<h5>Syntax:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3264<pre>
Devang Patel307e8ab2008-10-07 17:48:33 +0000[diff] [blame]3265 &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]3266 to label &lt;normal label&gt; unwind label &lt;exception label&gt;
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3267</pre>
3268
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]3269<h5>Overview:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3270<p>The '<tt>invoke</tt>' instruction causes control to transfer to a specified
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3271 function, with the possibility of control flow transfer to either the
3272 '<tt>normal</tt>' label or the '<tt>exception</tt>' label. If the callee
3273 function returns with the "<tt><a href="#i_ret">ret</a></tt>" instruction,
3274 control flow will return to the "normal" label. If the callee (or any
3275 indirect callees) returns with the "<a href="#i_unwind"><tt>unwind</tt></a>"
3276 instruction, control is interrupted and continued at the dynamically nearest
3277 "exception" label.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3278
Bill Wendlingf78faf82011-08-02 21:52:38 +0000[diff] [blame]3279<p>The '<tt>exception</tt>' label is a
3280 <i><a href="ExceptionHandling.html#overview">landing pad</a></i> for the
3281 exception. As such, '<tt>exception</tt>' label is required to have the
3282 "<a href="#i_landingpad"><tt>landingpad</tt></a>" instruction, which contains
3283 the information about about the behavior of the program after unwinding
3284 happens, as its first non-PHI instruction. The restrictions on the
3285 "<tt>landingpad</tt>" instruction's tightly couples it to the
3286 "<tt>invoke</tt>" instruction, so that the important information contained
3287 within the "<tt>landingpad</tt>" instruction can't be lost through normal
3288 code motion.</p>
3289
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3290<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3291<p>This instruction requires several arguments:</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3292
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3293<ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3294 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
3295 convention</a> the call should use. If none is specified, the call
3296 defaults to using C calling conventions.</li>
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]3297
3298 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3299 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
3300 '<tt>inreg</tt>' attributes are valid here.</li>
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]3301
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3302 <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]3303 function value being invoked. In most cases, this is a direct function
3304 invocation, but indirect <tt>invoke</tt>s are just as possible, branching
3305 off an arbitrary pointer to function value.</li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3306
3307 <li>'<tt>function ptr val</tt>': An LLVM value containing a pointer to a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3308 function to be invoked. </li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3309
3310 <li>'<tt>function args</tt>': argument list whose types match the function
Chris Lattner0724fbd2010-03-02 06:36:51 +0000[diff] [blame]3311 signature argument types and parameter attributes. All arguments must be
3312 of <a href="#t_firstclass">first class</a> type. If the function
3313 signature indicates the function accepts a variable number of arguments,
3314 the extra arguments can be specified.</li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3315
3316 <li>'<tt>normal label</tt>': the label reached when the called function
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3317 executes a '<tt><a href="#i_ret">ret</a></tt>' instruction. </li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3318
3319 <li>'<tt>exception label</tt>': the label reached when a callee returns with
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3320 the <a href="#i_unwind"><tt>unwind</tt></a> instruction. </li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3321
Devang Patel307e8ab2008-10-07 17:48:33 +0000[diff] [blame]3322 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3323 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
3324 '<tt>readnone</tt>' attributes are valid here.</li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3325</ol>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3326
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3327<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3328<p>This instruction is designed to operate as a standard
3329 '<tt><a href="#i_call">call</a></tt>' instruction in most regards. The
3330 primary difference is that it establishes an association with a label, which
3331 is used by the runtime library to unwind the stack.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3332
3333<p>This instruction is used in languages with destructors to ensure that proper
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3334 cleanup is performed in the case of either a <tt>longjmp</tt> or a thrown
3335 exception. Additionally, this is important for implementation of
3336 '<tt>catch</tt>' clauses in high-level languages that support them.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3337
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3338<p>For the purposes of the SSA form, the definition of the value returned by the
3339 '<tt>invoke</tt>' instruction is deemed to occur on the edge from the current
3340 block to the "normal" label. If the callee unwinds then no return value is
3341 available.</p>
Dan Gohmanf96a4992009-05-22 21:47:08 +0000[diff] [blame]3342
Chris Lattnerdf7a6802010-01-15 18:08:37 +0000[diff] [blame]3343<p>Note that the code generator does not yet completely support unwind, and
3344that the invoke/unwind semantics are likely to change in future versions.</p>
3345
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3346<h5>Example:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3347<pre>
Nick Lewyckyd703f652008-03-16 07:18:12 +0000[diff] [blame]3348 %retval = invoke i32 @Test(i32 15) to label %Continue
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]3349 unwind label %TestCleanup <i>; {i32}:retval set</i>
Nick Lewyckyd703f652008-03-16 07:18:12 +0000[diff] [blame]3350 %retval = invoke <a href="#callingconv">coldcc</a> i32 %Testfnptr(i32 15) to label %Continue
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]3351 unwind label %TestCleanup <i>; {i32}:retval set</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3352</pre>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3353
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3354</div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3355
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]3356<!-- _______________________________________________________________________ -->
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3357
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3358<h4>
3359 <a name="i_unwind">'<tt>unwind</tt>' Instruction</a>
3360</h4>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3361
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3362<div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3363
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]3364<h5>Syntax:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3365<pre>
3366 unwind
3367</pre>
3368
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]3369<h5>Overview:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3370<p>The '<tt>unwind</tt>' instruction unwinds the stack, continuing control flow
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3371 at the first callee in the dynamic call stack which used
3372 an <a href="#i_invoke"><tt>invoke</tt></a> instruction to perform the call.
3373 This is primarily used to implement exception handling.</p>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3374
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]3375<h5>Semantics:</h5>
Chris Lattner72ed2002008-04-19 21:01:16 +0000[diff] [blame]3376<p>The '<tt>unwind</tt>' instruction causes execution of the current function to
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3377 immediately halt. The dynamic call stack is then searched for the
3378 first <a href="#i_invoke"><tt>invoke</tt></a> instruction on the call stack.
3379 Once found, execution continues at the "exceptional" destination block
3380 specified by the <tt>invoke</tt> instruction. If there is no <tt>invoke</tt>
3381 instruction in the dynamic call chain, undefined behavior results.</p>
3382
Chris Lattnerdf7a6802010-01-15 18:08:37 +0000[diff] [blame]3383<p>Note that the code generator does not yet completely support unwind, and
3384that the invoke/unwind semantics are likely to change in future versions.</p>
3385
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3386</div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3387
Bill Wendlingdccc03b2011-07-31 06:30:59 +0000[diff] [blame]3388 <!-- _______________________________________________________________________ -->
3389
3390<h4>
3391 <a name="i_resume">'<tt>resume</tt>' Instruction</a>
3392</h4>
3393
3394<div>
3395
3396<h5>Syntax:</h5>
3397<pre>
3398 resume &lt;type&gt; &lt;value&gt;
3399</pre>
3400
3401<h5>Overview:</h5>
3402<p>The '<tt>resume</tt>' instruction is a terminator instruction that has no
3403 successors.</p>
3404
3405<h5>Arguments:</h5>
Bill Wendlingf78faf82011-08-02 21:52:38 +0000[diff] [blame]3406<p>The '<tt>resume</tt>' instruction requires one argument, which must have the
Bill Wendlinge4ad50b2011-08-03 18:37:32 +0000[diff] [blame]3407 same type as the result of any '<tt>landingpad</tt>' instruction in the same
3408 function.</p>
Bill Wendlingdccc03b2011-07-31 06:30:59 +0000[diff] [blame]3409
3410<h5>Semantics:</h5>
3411<p>The '<tt>resume</tt>' instruction resumes propagation of an existing
3412 (in-flight) exception whose unwinding was interrupted with
Bill Wendlingf78faf82011-08-02 21:52:38 +0000[diff] [blame]3413 a <a href="#i_landingpad"><tt>landingpad</tt></a> instruction.</p>
Bill Wendlingdccc03b2011-07-31 06:30:59 +0000[diff] [blame]3414
3415<h5>Example:</h5>
3416<pre>
Bill Wendlingf78faf82011-08-02 21:52:38 +0000[diff] [blame]3417 resume { i8*, i32 } %exn
Bill Wendlingdccc03b2011-07-31 06:30:59 +0000[diff] [blame]3418</pre>
3419
3420</div>
3421
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3422<!-- _______________________________________________________________________ -->
3423
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3424<h4>
3425 <a name="i_unreachable">'<tt>unreachable</tt>' Instruction</a>
3426</h4>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3427
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3428<div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3429
3430<h5>Syntax:</h5>
3431<pre>
3432 unreachable
3433</pre>
3434
3435<h5>Overview:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3436<p>The '<tt>unreachable</tt>' instruction has no defined semantics. This
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3437 instruction is used to inform the optimizer that a particular portion of the
3438 code is not reachable. This can be used to indicate that the code after a
3439 no-return function cannot be reached, and other facts.</p>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3440
3441<h5>Semantics:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3442<p>The '<tt>unreachable</tt>' instruction has no defined semantics.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3443
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3444</div>
3445
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3446</div>
3447
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3448<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3449<h3>
3450 <a name="binaryops">Binary Operations</a>
3451</h3>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3452
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3453<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3454
3455<p>Binary operators are used to do most of the computation in a program. They
3456 require two operands of the same type, execute an operation on them, and
3457 produce a single value. The operands might represent multiple data, as is
3458 the case with the <a href="#t_vector">vector</a> data type. The result value
3459 has the same type as its operands.</p>
3460
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3461<p>There are several different binary operators:</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3462
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3463<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3464<h4>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3465 <a name="i_add">'<tt>add</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3466</h4>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3467
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3468<div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3469
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3470<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3471<pre>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3472 &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]3473 &lt;result&gt; = add nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3474 &lt;result&gt; = add nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3475 &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]3476</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3477
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3478<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3479<p>The '<tt>add</tt>' instruction returns the sum of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3480
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3481<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3482<p>The two arguments to the '<tt>add</tt>' instruction must
3483 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3484 integer values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3485
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3486<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3487<p>The value produced is the integer sum of the two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3488
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3489<p>If the sum has unsigned overflow, the result returned is the mathematical
3490 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]3491
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3492<p>Because LLVM integers use a two's complement representation, this instruction
3493 is appropriate for both signed and unsigned integers.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3494
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]3495<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3496 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3497 <tt>nsw</tt> keywords are present, the result value of the <tt>add</tt>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]3498 is a <a href="#trapvalues">trap value</a> if unsigned and/or signed overflow,
3499 respectively, occurs.</p>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3500
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3501<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3502<pre>
3503 &lt;result&gt; = add i32 4, %var <i>; yields {i32}:result = 4 + %var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3504</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3505
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3506</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3507
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3508<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3509<h4>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3510 <a name="i_fadd">'<tt>fadd</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3511</h4>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3512
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3513<div>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3514
3515<h5>Syntax:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3516<pre>
3517 &lt;result&gt; = fadd &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3518</pre>
3519
3520<h5>Overview:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3521<p>The '<tt>fadd</tt>' instruction returns the sum of its two operands.</p>
3522
3523<h5>Arguments:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3524<p>The two arguments to the '<tt>fadd</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3525 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3526 floating point values. Both arguments must have identical types.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3527
3528<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3529<p>The value produced is the floating point sum of the two operands.</p>
3530
3531<h5>Example:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3532<pre>
3533 &lt;result&gt; = fadd float 4.0, %var <i>; yields {float}:result = 4.0 + %var</i>
3534</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3535
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3536</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3537
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3538<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3539<h4>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3540 <a name="i_sub">'<tt>sub</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3541</h4>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3542
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3543<div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3544
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3545<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3546<pre>
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]3547 &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]3548 &lt;result&gt; = sub nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3549 &lt;result&gt; = sub nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3550 &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]3551</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3552
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3553<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3554<p>The '<tt>sub</tt>' instruction returns the difference of its two
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3555 operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3556
3557<p>Note that the '<tt>sub</tt>' instruction is used to represent the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3558 '<tt>neg</tt>' instruction present in most other intermediate
3559 representations.</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>sub</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 difference of the two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3568
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3569<p>If the difference has unsigned overflow, the result returned is the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3570 mathematical result modulo 2<sup>n</sup>, where n is the bit width of the
3571 result.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3572
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3573<p>Because LLVM integers use a two's complement representation, this instruction
3574 is appropriate for both signed and unsigned integers.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3575
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]3576<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3577 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3578 <tt>nsw</tt> keywords are present, the result value of the <tt>sub</tt>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]3579 is a <a href="#trapvalues">trap value</a> if unsigned and/or signed overflow,
3580 respectively, occurs.</p>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3581
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3582<h5>Example:</h5>
Bill Wendlingaac388b2007-05-29 09:42:13 +0000[diff] [blame]3583<pre>
3584 &lt;result&gt; = sub i32 4, %var <i>; yields {i32}:result = 4 - %var</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3585 &lt;result&gt; = sub i32 0, %val <i>; yields {i32}:result = -%var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3586</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3587
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3588</div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3589
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3590<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3591<h4>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3592 <a name="i_fsub">'<tt>fsub</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3593</h4>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3594
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3595<div>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3596
3597<h5>Syntax:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3598<pre>
3599 &lt;result&gt; = fsub &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3600</pre>
3601
3602<h5>Overview:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3603<p>The '<tt>fsub</tt>' instruction returns the difference of its two
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3604 operands.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3605
3606<p>Note that the '<tt>fsub</tt>' instruction is used to represent the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3607 '<tt>fneg</tt>' instruction present in most other intermediate
3608 representations.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3609
3610<h5>Arguments:</h5>
Bill Wendlingd9fe2982009-07-20 02:32:41 +0000[diff] [blame]3611<p>The two arguments to the '<tt>fsub</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3612 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3613 floating point values. Both arguments must have identical types.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3614
3615<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3616<p>The value produced is the floating point difference of the two operands.</p>
3617
3618<h5>Example:</h5>
3619<pre>
3620 &lt;result&gt; = fsub float 4.0, %var <i>; yields {float}:result = 4.0 - %var</i>
3621 &lt;result&gt; = fsub float -0.0, %val <i>; yields {float}:result = -%var</i>
3622</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3623
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3624</div>
3625
3626<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3627<h4>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3628 <a name="i_mul">'<tt>mul</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3629</h4>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3630
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3631<div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3632
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3633<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3634<pre>
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]3635 &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]3636 &lt;result&gt; = mul nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3637 &lt;result&gt; = mul nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3638 &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]3639</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3640
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3641<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3642<p>The '<tt>mul</tt>' instruction returns the product of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3643
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3644<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3645<p>The two arguments to the '<tt>mul</tt>' instruction must
3646 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3647 integer values. Both arguments must have identical types.</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3648
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3649<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3650<p>The value produced is the integer product of the two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3651
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3652<p>If the result of the multiplication has unsigned overflow, the result
3653 returned is the mathematical result modulo 2<sup>n</sup>, where n is the bit
3654 width of the result.</p>
3655
3656<p>Because LLVM integers use a two's complement representation, and the result
3657 is the same width as the operands, this instruction returns the correct
3658 result for both signed and unsigned integers. If a full product
3659 (e.g. <tt>i32</tt>x<tt>i32</tt>-><tt>i64</tt>) is needed, the operands should
3660 be sign-extended or zero-extended as appropriate to the width of the full
3661 product.</p>
3662
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]3663<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3664 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3665 <tt>nsw</tt> keywords are present, the result value of the <tt>mul</tt>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]3666 is a <a href="#trapvalues">trap value</a> if unsigned and/or signed overflow,
3667 respectively, occurs.</p>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3668
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3669<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3670<pre>
3671 &lt;result&gt; = mul i32 4, %var <i>; yields {i32}:result = 4 * %var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3672</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3673
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3674</div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3675
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3676<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3677<h4>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3678 <a name="i_fmul">'<tt>fmul</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3679</h4>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3680
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3681<div>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3682
3683<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3684<pre>
3685 &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]3686</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3687
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3688<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3689<p>The '<tt>fmul</tt>' instruction returns the product of its two operands.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3690
3691<h5>Arguments:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3692<p>The two arguments to the '<tt>fmul</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3693 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3694 floating point values. Both arguments must have identical types.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3695
3696<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3697<p>The value produced is the floating point product of the two operands.</p>
3698
3699<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3700<pre>
3701 &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]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>
3708 <a name="i_udiv">'<tt>udiv</tt>' Instruction</a>
3709</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3710
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3711<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3712
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3713<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3714<pre>
Chris Lattner35bda892011-02-06 21:44:57 +0000[diff] [blame]3715 &lt;result&gt; = udiv &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3716 &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]3717</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3718
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3719<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3720<p>The '<tt>udiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3721
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3722<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3723<p>The two arguments to the '<tt>udiv</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3724 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3725 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3726
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3727<h5>Semantics:</h5>
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3728<p>The value produced is the unsigned integer quotient of the two operands.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3729
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3730<p>Note that unsigned integer division and signed integer division are distinct
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3731 operations; for signed integer division, use '<tt>sdiv</tt>'.</p>
3732
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3733<p>Division by zero leads to undefined behavior.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3734
Chris Lattner35bda892011-02-06 21:44:57 +0000[diff] [blame]3735<p>If the <tt>exact</tt> keyword is present, the result value of the
3736 <tt>udiv</tt> is a <a href="#trapvalues">trap value</a> if %op1 is not a
3737 multiple of %op2 (as such, "((a udiv exact b) mul b) == a").</p>
3738
3739
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3740<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3741<pre>
3742 &lt;result&gt; = udiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3743</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3744
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3745</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3746
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3747<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3748<h4>
3749 <a name="i_sdiv">'<tt>sdiv</tt>' Instruction</a>
3750</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3751
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3752<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3753
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3754<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3755<pre>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3756 &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]3757 &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]3758</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3759
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3760<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3761<p>The '<tt>sdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3762
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3763<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3764<p>The two arguments to the '<tt>sdiv</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3765 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3766 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3767
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3768<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3769<p>The value produced is the signed integer quotient of the two operands rounded
3770 towards zero.</p>
3771
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3772<p>Note that signed integer division and unsigned integer division are distinct
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3773 operations; for unsigned integer division, use '<tt>udiv</tt>'.</p>
3774
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3775<p>Division by zero leads to undefined behavior. Overflow also leads to
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3776 undefined behavior; this is a rare case, but can occur, for example, by doing
3777 a 32-bit division of -2147483648 by -1.</p>
3778
Dan Gohman9c5beed2009-07-22 00:04:19 +0000[diff] [blame]3779<p>If the <tt>exact</tt> keyword is present, the result value of the
Dan Gohman27ef9972010-04-23 15:23:32 +0000[diff] [blame]3780 <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]3781 be rounded.</p>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3782
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3783<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3784<pre>
3785 &lt;result&gt; = sdiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3786</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3787
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3788</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3789
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3790<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3791<h4>
3792 <a name="i_fdiv">'<tt>fdiv</tt>' Instruction</a>
3793</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3794
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3795<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3796
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3797<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3798<pre>
Gabor Greiffb224a22008-08-07 21:46:00 +0000[diff] [blame]3799 &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]3800</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3801
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3802<h5>Overview:</h5>
3803<p>The '<tt>fdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3804
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3805<h5>Arguments:</h5>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]3806<p>The two arguments to the '<tt>fdiv</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3807 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3808 floating point values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3809
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3810<h5>Semantics:</h5>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3811<p>The value produced is the floating point quotient of the two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3812
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3813<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3814<pre>
3815 &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]3816</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3817
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3818</div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3819
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3820<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3821<h4>
3822 <a name="i_urem">'<tt>urem</tt>' Instruction</a>
3823</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3824
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3825<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3826
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3827<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3828<pre>
3829 &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]3830</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3831
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3832<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3833<p>The '<tt>urem</tt>' instruction returns the remainder from the unsigned
3834 division of its two arguments.</p>
3835
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3836<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3837<p>The two arguments to the '<tt>urem</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3838 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3839 values. Both arguments must have identical types.</p>
3840
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3841<h5>Semantics:</h5>
3842<p>This instruction returns the unsigned integer <i>remainder</i> of a division.
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3843 This instruction always performs an unsigned division to get the
3844 remainder.</p>
3845
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3846<p>Note that unsigned integer remainder and signed integer remainder are
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3847 distinct operations; for signed integer remainder, use '<tt>srem</tt>'.</p>
3848
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3849<p>Taking the remainder of a division by zero leads to undefined behavior.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3850
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3851<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3852<pre>
3853 &lt;result&gt; = urem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3854</pre>
3855
3856</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3857
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3858<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3859<h4>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3860 <a name="i_srem">'<tt>srem</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3861</h4>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3862
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3863<div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3864
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3865<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3866<pre>
Gabor Greiffb224a22008-08-07 21:46:00 +0000[diff] [blame]3867 &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]3868</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3869
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3870<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3871<p>The '<tt>srem</tt>' instruction returns the remainder from the signed
3872 division of its two operands. This instruction can also take
3873 <a href="#t_vector">vector</a> versions of the values in which case the
3874 elements must be integers.</p>
Chris Lattnerc7d3ab32008-01-04 04:33:49 +0000[diff] [blame]3875
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3876<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3877<p>The two arguments to the '<tt>srem</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3878 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3879 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3880
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3881<h5>Semantics:</h5>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3882<p>This instruction returns the <i>remainder</i> of a division (where the result
Duncan Sandsdea3a5e2011-03-07 09:12:24 +0000[diff] [blame]3883 is either zero or has the same sign as the dividend, <tt>op1</tt>), not the
3884 <i>modulo</i> operator (where the result is either zero or has the same sign
3885 as the divisor, <tt>op2</tt>) of a value.
3886 For more information about the difference,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3887 see <a href="http://mathforum.org/dr.math/problems/anne.4.28.99.html">The
3888 Math Forum</a>. For a table of how this is implemented in various languages,
3889 please see <a href="http://en.wikipedia.org/wiki/Modulo_operation">
3890 Wikipedia: modulo operation</a>.</p>
3891
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3892<p>Note that signed integer remainder and unsigned integer remainder are
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3893 distinct operations; for unsigned integer remainder, use '<tt>urem</tt>'.</p>
3894
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3895<p>Taking the remainder of a division by zero leads to undefined behavior.
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3896 Overflow also leads to undefined behavior; this is a rare case, but can
3897 occur, for example, by taking the remainder of a 32-bit division of
3898 -2147483648 by -1. (The remainder doesn't actually overflow, but this rule
3899 lets srem be implemented using instructions that return both the result of
3900 the division and the remainder.)</p>
3901
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3902<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3903<pre>
3904 &lt;result&gt; = srem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3905</pre>
3906
3907</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3908
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3909<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3910<h4>
3911 <a name="i_frem">'<tt>frem</tt>' Instruction</a>
3912</h4>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3913
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3914<div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3915
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3916<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3917<pre>
3918 &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]3919</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3920
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3921<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3922<p>The '<tt>frem</tt>' instruction returns the remainder from the division of
3923 its two operands.</p>
3924
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3925<h5>Arguments:</h5>
3926<p>The two arguments to the '<tt>frem</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3927 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3928 floating point values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3929
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3930<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3931<p>This instruction returns the <i>remainder</i> of a division. The remainder
3932 has the same sign as the dividend.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3933
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3934<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3935<pre>
3936 &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]3937</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3938
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3939</div>
Robert Bocchino7b81c752006-02-17 21:18:08 +0000[diff] [blame]3940
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3941</div>
3942
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]3943<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3944<h3>
3945 <a name="bitwiseops">Bitwise Binary Operations</a>
3946</h3>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3947
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3948<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3949
3950<p>Bitwise binary operators are used to do various forms of bit-twiddling in a
3951 program. They are generally very efficient instructions and can commonly be
3952 strength reduced from other instructions. They require two operands of the
3953 same type, execute an operation on them, and produce a single value. The
3954 resulting value is the same type as its operands.</p>
3955
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3956<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3957<h4>
3958 <a name="i_shl">'<tt>shl</tt>' Instruction</a>
3959</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3960
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3961<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3962
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3963<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3964<pre>
Chris Lattnerf067d582011-02-07 16:40:21 +0000[diff] [blame]3965 &lt;result&gt; = shl &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3966 &lt;result&gt; = shl nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3967 &lt;result&gt; = shl nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3968 &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]3969</pre>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3970
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3971<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3972<p>The '<tt>shl</tt>' instruction returns the first operand shifted to the left
3973 a specified number of bits.</p>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3974
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3975<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3976<p>Both arguments to the '<tt>shl</tt>' instruction must be the
3977 same <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3978 integer type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3979
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3980<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3981<p>The value produced is <tt>op1</tt> * 2<sup><tt>op2</tt></sup> mod
3982 2<sup>n</sup>, where <tt>n</tt> is the width of the result. If <tt>op2</tt>
3983 is (statically or dynamically) negative or equal to or larger than the number
3984 of bits in <tt>op1</tt>, the result is undefined. If the arguments are
3985 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
3986 shift amount in <tt>op2</tt>.</p>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3987
Chris Lattnerf067d582011-02-07 16:40:21 +0000[diff] [blame]3988<p>If the <tt>nuw</tt> keyword is present, then the shift produces a
3989 <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]3990 the <tt>nsw</tt> keyword is present, then the shift produces a
Chris Lattnerf067d582011-02-07 16:40:21 +0000[diff] [blame]3991 <a href="#trapvalues">trap value</a> if it shifts out any bits that disagree
3992 with the resultant sign bit. As such, NUW/NSW have the same semantics as
3993 they would if the shift were expressed as a mul instruction with the same
3994 nsw/nuw bits in (mul %op1, (shl 1, %op2)).</p>
3995
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3996<h5>Example:</h5>
3997<pre>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3998 &lt;result&gt; = shl i32 4, %var <i>; yields {i32}: 4 &lt;&lt; %var</i>
3999 &lt;result&gt; = shl i32 4, 2 <i>; yields {i32}: 16</i>
4000 &lt;result&gt; = shl i32 1, 10 <i>; yields {i32}: 1024</i>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]4001 &lt;result&gt; = shl i32 1, 32 <i>; undefined</i>
Mon P Wange9f10152008-12-09 05:46:39 +0000[diff] [blame]4002 &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]4003</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4004
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4005</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4006
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4007<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4008<h4>
4009 <a name="i_lshr">'<tt>lshr</tt>' Instruction</a>
4010</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4011
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4012<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4013
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4014<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4015<pre>
Chris Lattnerf067d582011-02-07 16:40:21 +0000[diff] [blame]4016 &lt;result&gt; = lshr &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
4017 &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]4018</pre>
4019
4020<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4021<p>The '<tt>lshr</tt>' instruction (logical shift right) returns the first
4022 operand shifted to the right a specified number of bits with zero fill.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4023
4024<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4025<p>Both arguments to the '<tt>lshr</tt>' instruction must be the same
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4026 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
4027 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4028
4029<h5>Semantics:</h5>
4030<p>This instruction always performs a logical shift right operation. The most
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4031 significant bits of the result will be filled with zero bits after the shift.
4032 If <tt>op2</tt> is (statically or dynamically) equal to or larger than the
4033 number of bits in <tt>op1</tt>, the result is undefined. If the arguments are
4034 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
4035 shift amount in <tt>op2</tt>.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4036
Chris Lattnerf067d582011-02-07 16:40:21 +0000[diff] [blame]4037<p>If the <tt>exact</tt> keyword is present, the result value of the
4038 <tt>lshr</tt> is a <a href="#trapvalues">trap value</a> if any of the bits
4039 shifted out are non-zero.</p>
4040
4041
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4042<h5>Example:</h5>
4043<pre>
4044 &lt;result&gt; = lshr i32 4, 1 <i>; yields {i32}:result = 2</i>
4045 &lt;result&gt; = lshr i32 4, 2 <i>; yields {i32}:result = 1</i>
4046 &lt;result&gt; = lshr i8 4, 3 <i>; yields {i8}:result = 0</i>
4047 &lt;result&gt; = lshr i8 -2, 1 <i>; yields {i8}:result = 0x7FFFFFFF </i>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]4048 &lt;result&gt; = lshr i32 1, 32 <i>; undefined</i>
Mon P Wange9f10152008-12-09 05:46:39 +0000[diff] [blame]4049 &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]4050</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4051
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4052</div>
4053
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]4054<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4055<h4>
4056 <a name="i_ashr">'<tt>ashr</tt>' Instruction</a>
4057</h4>
4058
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4059<div>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4060
4061<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4062<pre>
Chris Lattnerf067d582011-02-07 16:40:21 +0000[diff] [blame]4063 &lt;result&gt; = ashr &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
4064 &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]4065</pre>
4066
4067<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4068<p>The '<tt>ashr</tt>' instruction (arithmetic shift right) returns the first
4069 operand shifted to the right a specified number of bits with sign
4070 extension.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4071
4072<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4073<p>Both arguments to the '<tt>ashr</tt>' instruction must be the same
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4074 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
4075 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4076
4077<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4078<p>This instruction always performs an arithmetic shift right operation, The
4079 most significant bits of the result will be filled with the sign bit
4080 of <tt>op1</tt>. If <tt>op2</tt> is (statically or dynamically) equal to or
4081 larger than the number of bits in <tt>op1</tt>, the result is undefined. If
4082 the arguments are vectors, each vector element of <tt>op1</tt> is shifted by
4083 the corresponding shift amount in <tt>op2</tt>.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4084
Chris Lattnerf067d582011-02-07 16:40:21 +0000[diff] [blame]4085<p>If the <tt>exact</tt> keyword is present, the result value of the
4086 <tt>ashr</tt> is a <a href="#trapvalues">trap value</a> if any of the bits
4087 shifted out are non-zero.</p>
4088
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4089<h5>Example:</h5>
4090<pre>
4091 &lt;result&gt; = ashr i32 4, 1 <i>; yields {i32}:result = 2</i>
4092 &lt;result&gt; = ashr i32 4, 2 <i>; yields {i32}:result = 1</i>
4093 &lt;result&gt; = ashr i8 4, 3 <i>; yields {i8}:result = 0</i>
4094 &lt;result&gt; = ashr i8 -2, 1 <i>; yields {i8}:result = -1</i>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]4095 &lt;result&gt; = ashr i32 1, 32 <i>; undefined</i>
Mon P Wange9f10152008-12-09 05:46:39 +0000[diff] [blame]4096 &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]4097</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4098
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4099</div>
4100
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4101<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4102<h4>
4103 <a name="i_and">'<tt>and</tt>' Instruction</a>
4104</h4>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4105
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4106<div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4107
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4108<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4109<pre>
Gabor Greiffb224a22008-08-07 21:46:00 +0000[diff] [blame]4110 &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]4111</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4112
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4113<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4114<p>The '<tt>and</tt>' instruction returns the bitwise logical and of its two
4115 operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4116
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4117<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4118<p>The two arguments to the '<tt>and</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4119 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
4120 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4121
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4122<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4123<p>The truth table used for the '<tt>and</tt>' instruction is:</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4124
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4125<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4126 <tbody>
4127 <tr>
4128 <td>In0</td>
4129 <td>In1</td>
4130 <td>Out</td>
4131 </tr>
4132 <tr>
4133 <td>0</td>
4134 <td>0</td>
4135 <td>0</td>
4136 </tr>
4137 <tr>
4138 <td>0</td>
4139 <td>1</td>
4140 <td>0</td>
4141 </tr>
4142 <tr>
4143 <td>1</td>
4144 <td>0</td>
4145 <td>0</td>
4146 </tr>
4147 <tr>
4148 <td>1</td>
4149 <td>1</td>
4150 <td>1</td>
4151 </tr>
4152 </tbody>
4153</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4154
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4155<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4156<pre>
4157 &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]4158 &lt;result&gt; = and i32 15, 40 <i>; yields {i32}:result = 8</i>
4159 &lt;result&gt; = and i32 4, 8 <i>; yields {i32}:result = 0</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4160</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4161</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4162<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4163<h4>
4164 <a name="i_or">'<tt>or</tt>' Instruction</a>
4165</h4>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4166
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4167<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4168
4169<h5>Syntax:</h5>
4170<pre>
4171 &lt;result&gt; = or &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
4172</pre>
4173
4174<h5>Overview:</h5>
4175<p>The '<tt>or</tt>' instruction returns the bitwise logical inclusive or of its
4176 two operands.</p>
4177
4178<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4179<p>The two arguments to the '<tt>or</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4180 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
4181 values. Both arguments must have identical types.</p>
4182
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4183<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4184<p>The truth table used for the '<tt>or</tt>' instruction is:</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4185
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4186<table border="1" cellspacing="0" cellpadding="4">
4187 <tbody>
4188 <tr>
4189 <td>In0</td>
4190 <td>In1</td>
4191 <td>Out</td>
4192 </tr>
4193 <tr>
4194 <td>0</td>
4195 <td>0</td>
4196 <td>0</td>
4197 </tr>
4198 <tr>
4199 <td>0</td>
4200 <td>1</td>
4201 <td>1</td>
4202 </tr>
4203 <tr>
4204 <td>1</td>
4205 <td>0</td>
4206 <td>1</td>
4207 </tr>
4208 <tr>
4209 <td>1</td>
4210 <td>1</td>
4211 <td>1</td>
4212 </tr>
4213 </tbody>
4214</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4215
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4216<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4217<pre>
4218 &lt;result&gt; = or i32 4, %var <i>; yields {i32}:result = 4 | %var</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4219 &lt;result&gt; = or i32 15, 40 <i>; yields {i32}:result = 47</i>
4220 &lt;result&gt; = or i32 4, 8 <i>; yields {i32}:result = 12</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4221</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4222
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4223</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4224
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4225<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4226<h4>
4227 <a name="i_xor">'<tt>xor</tt>' Instruction</a>
4228</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4229
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4230<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4231
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4232<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4233<pre>
4234 &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]4235</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4236
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4237<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4238<p>The '<tt>xor</tt>' instruction returns the bitwise logical exclusive or of
4239 its two operands. The <tt>xor</tt> is used to implement the "one's
4240 complement" operation, which is the "~" operator in C.</p>
4241
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4242<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4243<p>The two arguments to the '<tt>xor</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4244 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
4245 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4246
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4247<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4248<p>The truth table used for the '<tt>xor</tt>' instruction is:</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4249
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4250<table border="1" cellspacing="0" cellpadding="4">
4251 <tbody>
4252 <tr>
4253 <td>In0</td>
4254 <td>In1</td>
4255 <td>Out</td>
4256 </tr>
4257 <tr>
4258 <td>0</td>
4259 <td>0</td>
4260 <td>0</td>
4261 </tr>
4262 <tr>
4263 <td>0</td>
4264 <td>1</td>
4265 <td>1</td>
4266 </tr>
4267 <tr>
4268 <td>1</td>
4269 <td>0</td>
4270 <td>1</td>
4271 </tr>
4272 <tr>
4273 <td>1</td>
4274 <td>1</td>
4275 <td>0</td>
4276 </tr>
4277 </tbody>
4278</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4279
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4280<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4281<pre>
4282 &lt;result&gt; = xor i32 4, %var <i>; yields {i32}:result = 4 ^ %var</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4283 &lt;result&gt; = xor i32 15, 40 <i>; yields {i32}:result = 39</i>
4284 &lt;result&gt; = xor i32 4, 8 <i>; yields {i32}:result = 12</i>
4285 &lt;result&gt; = xor i32 %V, -1 <i>; yields {i32}:result = ~%V</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4286</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4287
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4288</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4289
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4290</div>
4291
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4292<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4293<h3>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4294 <a name="vectorops">Vector Operations</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4295</h3>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4296
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4297<div>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4298
4299<p>LLVM supports several instructions to represent vector operations in a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4300 target-independent manner. These instructions cover the element-access and
4301 vector-specific operations needed to process vectors effectively. While LLVM
4302 does directly support these vector operations, many sophisticated algorithms
4303 will want to use target-specific intrinsics to take full advantage of a
4304 specific target.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4305
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4306<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4307<h4>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4308 <a name="i_extractelement">'<tt>extractelement</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4309</h4>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4310
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4311<div>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4312
4313<h5>Syntax:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4314<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4315 &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]4316</pre>
4317
4318<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4319<p>The '<tt>extractelement</tt>' instruction extracts a single scalar element
4320 from a vector at a specified index.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4321
4322
4323<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4324<p>The first operand of an '<tt>extractelement</tt>' instruction is a value
4325 of <a href="#t_vector">vector</a> type. The second operand is an index
4326 indicating the position from which to extract the element. The index may be
4327 a variable.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4328
4329<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4330<p>The result is a scalar of the same type as the element type of
4331 <tt>val</tt>. Its value is the value at position <tt>idx</tt> of
4332 <tt>val</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
4333 results are undefined.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4334
4335<h5>Example:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4336<pre>
Gabor Greifa5b6f452009-10-28 13:14:50 +0000[diff] [blame]4337 &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]4338</pre>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4339
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4340</div>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4341
4342<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4343<h4>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4344 <a name="i_insertelement">'<tt>insertelement</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4345</h4>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4346
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4347<div>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4348
4349<h5>Syntax:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4350<pre>
Dan Gohmanf3480b92008-05-12 23:38:42 +0000[diff] [blame]4351 &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]4352</pre>
4353
4354<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4355<p>The '<tt>insertelement</tt>' instruction inserts a scalar element into a
4356 vector at a specified index.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4357
4358<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4359<p>The first operand of an '<tt>insertelement</tt>' instruction is a value
4360 of <a href="#t_vector">vector</a> type. The second operand is a scalar value
4361 whose type must equal the element type of the first operand. The third
4362 operand is an index indicating the position at which to insert the value.
4363 The index may be a variable.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4364
4365<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4366<p>The result is a vector of the same type as <tt>val</tt>. Its element values
4367 are those of <tt>val</tt> except at position <tt>idx</tt>, where it gets the
4368 value <tt>elt</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
4369 results are undefined.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4370
4371<h5>Example:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4372<pre>
Gabor Greifa5b6f452009-10-28 13:14:50 +0000[diff] [blame]4373 &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]4374</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4375
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4376</div>
4377
4378<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4379<h4>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4380 <a name="i_shufflevector">'<tt>shufflevector</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4381</h4>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4382
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4383<div>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4384
4385<h5>Syntax:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4386<pre>
Mon P Wangaeb06d22008-11-10 04:46:22 +0000[diff] [blame]4387 &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]4388</pre>
4389
4390<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4391<p>The '<tt>shufflevector</tt>' instruction constructs a permutation of elements
4392 from two input vectors, returning a vector with the same element type as the
4393 input and length that is the same as the shuffle mask.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4394
4395<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4396<p>The first two operands of a '<tt>shufflevector</tt>' instruction are vectors
4397 with types that match each other. The third argument is a shuffle mask whose
4398 element type is always 'i32'. The result of the instruction is a vector
4399 whose length is the same as the shuffle mask and whose element type is the
4400 same as the element type of the first two operands.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4401
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4402<p>The shuffle mask operand is required to be a constant vector with either
4403 constant integer or undef values.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4404
4405<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4406<p>The elements of the two input vectors are numbered from left to right across
4407 both of the vectors. The shuffle mask operand specifies, for each element of
4408 the result vector, which element of the two input vectors the result element
4409 gets. The element selector may be undef (meaning "don't care") and the
4410 second operand may be undef if performing a shuffle from only one vector.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4411
4412<h5>Example:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4413<pre>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4414 &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]4415 &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]4416 &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]4417 &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]4418 &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]4419 &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]4420 &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]4421 &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]4422</pre>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4423
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4424</div>
Tanya Lattner09474292006-04-14 19:24:33 +0000[diff] [blame]4425
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4426</div>
4427
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4428<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4429<h3>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4430 <a name="aggregateops">Aggregate Operations</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4431</h3>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4432
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4433<div>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4434
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4435<p>LLVM supports several instructions for working with
4436 <a href="#t_aggregate">aggregate</a> values.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4437
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4438<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4439<h4>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4440 <a name="i_extractvalue">'<tt>extractvalue</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4441</h4>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4442
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4443<div>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4444
4445<h5>Syntax:</h5>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4446<pre>
4447 &lt;result&gt; = extractvalue &lt;aggregate type&gt; &lt;val&gt;, &lt;idx&gt;{, &lt;idx&gt;}*
4448</pre>
4449
4450<h5>Overview:</h5>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4451<p>The '<tt>extractvalue</tt>' instruction extracts the value of a member field
4452 from an <a href="#t_aggregate">aggregate</a> value.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4453
4454<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4455<p>The first operand of an '<tt>extractvalue</tt>' instruction is a value
Chris Lattner61c70e92010-08-28 04:09:24 +0000[diff] [blame]4456 of <a href="#t_struct">struct</a> or
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4457 <a href="#t_array">array</a> type. The operands are constant indices to
4458 specify which value to extract in a similar manner as indices in a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4459 '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
Frits van Bommel13242892010-12-05 20:54:38 +0000[diff] [blame]4460 <p>The major differences to <tt>getelementptr</tt> indexing are:</p>
4461 <ul>
4462 <li>Since the value being indexed is not a pointer, the first index is
4463 omitted and assumed to be zero.</li>
4464 <li>At least one index must be specified.</li>
4465 <li>Not only struct indices but also array indices must be in
4466 bounds.</li>
4467 </ul>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4468
4469<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4470<p>The result is the value at the position in the aggregate specified by the
4471 index operands.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4472
4473<h5>Example:</h5>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4474<pre>
Gabor Greifa5b6f452009-10-28 13:14:50 +0000[diff] [blame]4475 &lt;result&gt; = extractvalue {i32, float} %agg, 0 <i>; yields i32</i>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4476</pre>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4477
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4478</div>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4479
4480<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4481<h4>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4482 <a name="i_insertvalue">'<tt>insertvalue</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4483</h4>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4484
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4485<div>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4486
4487<h5>Syntax:</h5>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4488<pre>
Bill Wendling194229e2011-07-26 20:42:28 +0000[diff] [blame]4489 &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]4490</pre>
4491
4492<h5>Overview:</h5>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4493<p>The '<tt>insertvalue</tt>' instruction inserts a value into a member field
4494 in an <a href="#t_aggregate">aggregate</a> value.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4495
4496<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4497<p>The first operand of an '<tt>insertvalue</tt>' instruction is a value
Chris Lattner61c70e92010-08-28 04:09:24 +0000[diff] [blame]4498 of <a href="#t_struct">struct</a> or
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4499 <a href="#t_array">array</a> type. The second operand is a first-class
4500 value to insert. The following operands are constant indices indicating
4501 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]4502 '<tt><a href="#i_extractvalue">extractvalue</a></tt>' instruction. The
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4503 value to insert must have the same type as the value identified by the
4504 indices.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4505
4506<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4507<p>The result is an aggregate of the same type as <tt>val</tt>. Its value is
4508 that of <tt>val</tt> except that the value at the position specified by the
4509 indices is that of <tt>elt</tt>.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4510
4511<h5>Example:</h5>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4512<pre>
Chris Lattner8645d1a2011-05-22 07:18:08 +0000[diff] [blame]4513 %agg1 = insertvalue {i32, float} undef, i32 1, 0 <i>; yields {i32 1, float undef}</i>
4514 %agg2 = insertvalue {i32, float} %agg1, float %val, 1 <i>; yields {i32 1, float %val}</i>
4515 %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]4516</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4517
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4518</div>
4519
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4520</div>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4521
4522<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4523<h3>
Chris Lattner884a9702006-08-15 00:45:58 +0000[diff] [blame]4524 <a name="memoryops">Memory Access and Addressing Operations</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4525</h3>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4526
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4527<div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4528
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4529<p>A key design point of an SSA-based representation is how it represents
4530 memory. In LLVM, no memory locations are in SSA form, which makes things
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]4531 very simple. This section describes how to read, write, and allocate
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4532 memory in LLVM.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4533
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4534<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4535<h4>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4536 <a name="i_alloca">'<tt>alloca</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4537</h4>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4538
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4539<div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4540
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4541<h5>Syntax:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4542<pre>
Dan Gohmanf75a7d32010-05-28 01:14:11 +0000[diff] [blame]4543 &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]4544</pre>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4545
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4546<h5>Overview:</h5>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]4547<p>The '<tt>alloca</tt>' instruction allocates memory on the stack frame of the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4548 currently executing function, to be automatically released when this function
4549 returns to its caller. The object is always allocated in the generic address
4550 space (address space zero).</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4551
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4552<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4553<p>The '<tt>alloca</tt>' instruction
4554 allocates <tt>sizeof(&lt;type&gt;)*NumElements</tt> bytes of memory on the
4555 runtime stack, returning a pointer of the appropriate type to the program.
4556 If "NumElements" is specified, it is the number of elements allocated,
4557 otherwise "NumElements" is defaulted to be one. If a constant alignment is
4558 specified, the value result of the allocation is guaranteed to be aligned to
4559 at least that boundary. If not specified, or if zero, the target can choose
4560 to align the allocation on any convenient boundary compatible with the
4561 type.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4562
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4563<p>'<tt>type</tt>' may be any sized type.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4564
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4565<h5>Semantics:</h5>
Bill Wendling871eb0a2009-05-08 20:49:29 +0000[diff] [blame]4566<p>Memory is allocated; a pointer is returned. The operation is undefined if
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4567 there is insufficient stack space for the allocation. '<tt>alloca</tt>'d
4568 memory is automatically released when the function returns. The
4569 '<tt>alloca</tt>' instruction is commonly used to represent automatic
4570 variables that must have an address available. When the function returns
4571 (either with the <tt><a href="#i_ret">ret</a></tt>
4572 or <tt><a href="#i_unwind">unwind</a></tt> instructions), the memory is
4573 reclaimed. Allocating zero bytes is legal, but the result is undefined.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4574
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4575<h5>Example:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4576<pre>
Dan Gohman81e21672009-01-04 23:49:44 +0000[diff] [blame]4577 %ptr = alloca i32 <i>; yields {i32*}:ptr</i>
4578 %ptr = alloca i32, i32 4 <i>; yields {i32*}:ptr</i>
4579 %ptr = alloca i32, i32 4, align 1024 <i>; yields {i32*}:ptr</i>
4580 %ptr = alloca i32, align 1024 <i>; yields {i32*}:ptr</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4581</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4582
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4583</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4584
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4585<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4586<h4>
4587 <a name="i_load">'<tt>load</tt>' Instruction</a>
4588</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4589
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4590<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4591
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4592<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4593<pre>
Eli Friedmanf03bb262011-08-12 22:50:01 +0000[diff] [blame]4594 &lt;result&gt; = load [volatile] &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;][, !nontemporal !&lt;index&gt;]
4595 &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]4596 !&lt;index&gt; = !{ i32 1 }
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4597</pre>
4598
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4599<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4600<p>The '<tt>load</tt>' instruction is used to read from memory.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4601
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4602<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4603<p>The argument to the '<tt>load</tt>' instruction specifies the memory address
4604 from which to load. The pointer must point to
4605 a <a href="#t_firstclass">first class</a> type. If the <tt>load</tt> is
4606 marked as <tt>volatile</tt>, then the optimizer is not allowed to modify the
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]4607 number or order of execution of this <tt>load</tt> with other <a
4608 href="#volatile">volatile operations</a>.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4609
Eli Friedman21006d42011-08-09 23:02:53 +0000[diff] [blame]4610<p>If the <code>load</code> is marked as <code>atomic</code>, it takes an extra
4611 <a href="#ordering">ordering</a> and optional <code>singlethread</code>
4612 argument. The <code>release</code> and <code>acq_rel</code> orderings are
4613 not valid on <code>load</code> instructions. Atomic loads produce <a
4614 href="#memorymodel">defined</a> results when they may see multiple atomic
4615 stores. The type of the pointee must be an integer type whose bit width
4616 is a power of two greater than or equal to eight and less than or equal
4617 to a target-specific size limit. <code>align</code> must be explicitly
4618 specified on atomic loads, and the load has undefined behavior if the
4619 alignment is not set to a value which is at least the size in bytes of
4620 the pointee. <code>!nontemporal</code> does not have any defined semantics
4621 for atomic loads.</p>
4622
Bill Wendling7c78dbb2010-02-25 21:23:24 +0000[diff] [blame]4623<p>The optional constant <tt>align</tt> argument specifies the alignment of the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4624 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]4625 omitted <tt>align</tt> argument means that the operation has the preferential
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4626 alignment for the target. It is the responsibility of the code emitter to
4627 ensure that the alignment information is correct. Overestimating the
Bill Wendling7c78dbb2010-02-25 21:23:24 +0000[diff] [blame]4628 alignment results in undefined behavior. Underestimating the alignment may
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4629 produce less efficient code. An alignment of 1 is always safe.</p>
4630
Bill Wendling7c78dbb2010-02-25 21:23:24 +0000[diff] [blame]4631<p>The optional <tt>!nontemporal</tt> metadata must reference a single
4632 metatadata name &lt;index&gt; corresponding to a metadata node with
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]4633 one <tt>i32</tt> entry of value 1. The existence of
Bill Wendling7c78dbb2010-02-25 21:23:24 +0000[diff] [blame]4634 the <tt>!nontemporal</tt> metatadata on the instruction tells the optimizer
4635 and code generator that this load is not expected to be reused in the cache.
4636 The code generator may select special instructions to save cache bandwidth,
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]4637 such as the <tt>MOVNT</tt> instruction on x86.</p>
David Greene8939b0d2010-02-16 20:50:18 +0000[diff] [blame]4638
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4639<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4640<p>The location of memory pointed to is loaded. If the value being loaded is of
4641 scalar type then the number of bytes read does not exceed the minimum number
4642 of bytes needed to hold all bits of the type. For example, loading an
4643 <tt>i24</tt> reads at most three bytes. When loading a value of a type like
4644 <tt>i20</tt> with a size that is not an integral number of bytes, the result
4645 is undefined if the value was not originally written using a store of the
4646 same type.</p>
4647
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4648<h5>Examples:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4649<pre>
4650 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
4651 <a href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4652 %val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4653</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4654
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4655</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4656
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4657<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4658<h4>
4659 <a name="i_store">'<tt>store</tt>' Instruction</a>
4660</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4661
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4662<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4663
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4664<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4665<pre>
Eli Friedmanf03bb262011-08-12 22:50:01 +0000[diff] [blame]4666 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>
4667 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]4668</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4669
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4670<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4671<p>The '<tt>store</tt>' instruction is used to write to memory.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4672
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4673<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4674<p>There are two arguments to the '<tt>store</tt>' instruction: a value to store
4675 and an address at which to store it. The type of the
4676 '<tt>&lt;pointer&gt;</tt>' operand must be a pointer to
4677 the <a href="#t_firstclass">first class</a> type of the
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]4678 '<tt>&lt;value&gt;</tt>' operand. If the <tt>store</tt> is marked as
4679 <tt>volatile</tt>, then the optimizer is not allowed to modify the number or
4680 order of execution of this <tt>store</tt> with other <a
4681 href="#volatile">volatile operations</a>.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4682
Eli Friedman21006d42011-08-09 23:02:53 +0000[diff] [blame]4683<p>If the <code>store</code> is marked as <code>atomic</code>, it takes an extra
4684 <a href="#ordering">ordering</a> and optional <code>singlethread</code>
4685 argument. The <code>acquire</code> and <code>acq_rel</code> orderings aren't
4686 valid on <code>store</code> instructions. Atomic loads produce <a
4687 href="#memorymodel">defined</a> results when they may see multiple atomic
4688 stores. The type of the pointee must be an integer type whose bit width
4689 is a power of two greater than or equal to eight and less than or equal
4690 to a target-specific size limit. <code>align</code> must be explicitly
4691 specified on atomic stores, and the store has undefined behavior if the
4692 alignment is not set to a value which is at least the size in bytes of
4693 the pointee. <code>!nontemporal</code> does not have any defined semantics
4694 for atomic stores.</p>
4695
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4696<p>The optional constant "align" argument specifies the alignment of the
4697 operation (that is, the alignment of the memory address). A value of 0 or an
4698 omitted "align" argument means that the operation has the preferential
4699 alignment for the target. It is the responsibility of the code emitter to
4700 ensure that the alignment information is correct. Overestimating the
4701 alignment results in an undefined behavior. Underestimating the alignment may
4702 produce less efficient code. An alignment of 1 is always safe.</p>
4703
David Greene8939b0d2010-02-16 20:50:18 +0000[diff] [blame]4704<p>The optional !nontemporal metadata must reference a single metatadata
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]4705 name &lt;index&gt; corresponding to a metadata node with one i32 entry of
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]4706 value 1. The existence of the !nontemporal metatadata on the
David Greene8939b0d2010-02-16 20:50:18 +0000[diff] [blame]4707 instruction tells the optimizer and code generator that this load is
4708 not expected to be reused in the cache. The code generator may
4709 select special instructions to save cache bandwidth, such as the
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]4710 MOVNT instruction on x86.</p>
David Greene8939b0d2010-02-16 20:50:18 +0000[diff] [blame]4711
4712
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4713<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4714<p>The contents of memory are updated to contain '<tt>&lt;value&gt;</tt>' at the
4715 location specified by the '<tt>&lt;pointer&gt;</tt>' operand. If
4716 '<tt>&lt;value&gt;</tt>' is of scalar type then the number of bytes written
4717 does not exceed the minimum number of bytes needed to hold all bits of the
4718 type. For example, storing an <tt>i24</tt> writes at most three bytes. When
4719 writing a value of a type like <tt>i20</tt> with a size that is not an
4720 integral number of bytes, it is unspecified what happens to the extra bits
4721 that do not belong to the type, but they will typically be overwritten.</p>
4722
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4723<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4724<pre>
4725 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Bill Wendling8c6c72d2007-10-22 05:10:05 +0000[diff] [blame]4726 store i32 3, i32* %ptr <i>; yields {void}</i>
4727 %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]4728</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4729
Reid Spencer47ce1792006-11-09 21:15:49 +0000[diff] [blame]4730</div>
4731
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4732<!-- _______________________________________________________________________ -->
NAKAMURA Takumib5bb29c2011-08-12 06:17:17 +0000[diff] [blame]4733<h4>
4734<a name="i_fence">'<tt>fence</tt>' Instruction</a>
4735</h4>
Eli Friedman47f35132011-07-25 23:16:38 +0000[diff] [blame]4736
NAKAMURA Takumib5bb29c2011-08-12 06:17:17 +0000[diff] [blame]4737<div>
Eli Friedman47f35132011-07-25 23:16:38 +0000[diff] [blame]4738
4739<h5>Syntax:</h5>
4740<pre>
4741 fence [singlethread] &lt;ordering&gt; <i>; yields {void}</i>
4742</pre>
4743
4744<h5>Overview:</h5>
4745<p>The '<tt>fence</tt>' instruction is used to introduce happens-before edges
4746between operations.</p>
4747
4748<h5>Arguments:</h5> <p>'<code>fence</code>' instructions take an <a
4749href="#ordering">ordering</a> argument which defines what
4750<i>synchronizes-with</i> edges they add. They can only be given
4751<code>acquire</code>, <code>release</code>, <code>acq_rel</code>, and
4752<code>seq_cst</code> orderings.</p>
4753
4754<h5>Semantics:</h5>
4755<p>A fence <var>A</var> which has (at least) <code>release</code> ordering
4756semantics <i>synchronizes with</i> a fence <var>B</var> with (at least)
4757<code>acquire</code> ordering semantics if and only if there exist atomic
4758operations <var>X</var> and <var>Y</var>, both operating on some atomic object
4759<var>M</var>, such that <var>A</var> is sequenced before <var>X</var>,
4760<var>X</var> modifies <var>M</var> (either directly or through some side effect
4761of a sequence headed by <var>X</var>), <var>Y</var> is sequenced before
4762<var>B</var>, and <var>Y</var> observes <var>M</var>. This provides a
4763<i>happens-before</i> dependency between <var>A</var> and <var>B</var>. Rather
4764than an explicit <code>fence</code>, one (but not both) of the atomic operations
4765<var>X</var> or <var>Y</var> might provide a <code>release</code> or
4766<code>acquire</code> (resp.) ordering constraint and still
4767<i>synchronize-with</i> the explicit <code>fence</code> and establish the
4768<i>happens-before</i> edge.</p>
4769
4770<p>A <code>fence</code> which has <code>seq_cst</code> ordering, in addition to
4771having both <code>acquire</code> and <code>release</code> semantics specified
4772above, participates in the global program order of other <code>seq_cst</code>
4773operations and/or fences.</p>
4774
4775<p>The optional "<a href="#singlethread"><code>singlethread</code></a>" argument
4776specifies that the fence only synchronizes with other fences in the same
4777thread. (This is useful for interacting with signal handlers.)</p>
4778
Eli Friedman47f35132011-07-25 23:16:38 +0000[diff] [blame]4779<h5>Example:</h5>
4780<pre>
4781 fence acquire <i>; yields {void}</i>
4782 fence singlethread seq_cst <i>; yields {void}</i>
4783</pre>
4784
4785</div>
4786
4787<!-- _______________________________________________________________________ -->
NAKAMURA Takumib5bb29c2011-08-12 06:17:17 +0000[diff] [blame]4788<h4>
4789<a name="i_cmpxchg">'<tt>cmpxchg</tt>' Instruction</a>
4790</h4>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]4791
NAKAMURA Takumib5bb29c2011-08-12 06:17:17 +0000[diff] [blame]4792<div>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]4793
4794<h5>Syntax:</h5>
4795<pre>
Eli Friedmanf03bb262011-08-12 22:50:01 +0000[diff] [blame]4796 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]4797</pre>
4798
4799<h5>Overview:</h5>
4800<p>The '<tt>cmpxchg</tt>' instruction is used to atomically modify memory.
4801It loads a value in memory and compares it to a given value. If they are
4802equal, it stores a new value into the memory.</p>
4803
4804<h5>Arguments:</h5>
4805<p>There are three arguments to the '<code>cmpxchg</code>' instruction: an
4806address to operate on, a value to compare to the value currently be at that
4807address, and a new value to place at that address if the compared values are
4808equal. The type of '<var>&lt;cmp&gt;</var>' must be an integer type whose
4809bit width is a power of two greater than or equal to eight and less than
4810or equal to a target-specific size limit. '<var>&lt;cmp&gt;</var>' and
4811'<var>&lt;new&gt;</var>' must have the same type, and the type of
4812'<var>&lt;pointer&gt;</var>' must be a pointer to that type. If the
4813<code>cmpxchg</code> is marked as <code>volatile</code>, then the
4814optimizer is not allowed to modify the number or order of execution
4815of this <code>cmpxchg</code> with other <a href="#volatile">volatile
4816operations</a>.</p>
4817
4818<!-- FIXME: Extend allowed types. -->
4819
4820<p>The <a href="#ordering"><var>ordering</var></a> argument specifies how this
4821<code>cmpxchg</code> synchronizes with other atomic operations.</p>
4822
4823<p>The optional "<code>singlethread</code>" argument declares that the
4824<code>cmpxchg</code> is only atomic with respect to code (usually signal
4825handlers) running in the same thread as the <code>cmpxchg</code>. Otherwise the
4826cmpxchg is atomic with respect to all other code in the system.</p>
4827
4828<p>The pointer passed into cmpxchg must have alignment greater than or equal to
4829the size in memory of the operand.
4830
4831<h5>Semantics:</h5>
4832<p>The contents of memory at the location specified by the
4833'<tt>&lt;pointer&gt;</tt>' operand is read and compared to
4834'<tt>&lt;cmp&gt;</tt>'; if the read value is the equal,
4835'<tt>&lt;new&gt;</tt>' is written. The original value at the location
4836is returned.
4837
4838<p>A successful <code>cmpxchg</code> is a read-modify-write instruction for the
4839purpose of identifying <a href="#release_sequence">release sequences</a>. A
4840failed <code>cmpxchg</code> is equivalent to an atomic load with an ordering
4841parameter determined by dropping any <code>release</code> part of the
4842<code>cmpxchg</code>'s ordering.</p>
4843
4844<!--
4845FIXME: Is compare_exchange_weak() necessary? (Consider after we've done
4846optimization work on ARM.)
4847
4848FIXME: Is a weaker ordering constraint on failure helpful in practice?
4849-->
4850
4851<h5>Example:</h5>
4852<pre>
4853entry:
4854 %orig = atomic <a href="#i_load">load</a> i32* %ptr unordered <i>; yields {i32}</i>
4855 <a href="#i_br">br</a> label %loop
4856
4857loop:
4858 %cmp = <a href="#i_phi">phi</a> i32 [ %orig, %entry ], [%old, %loop]
4859 %squared = <a href="#i_mul">mul</a> i32 %cmp, %cmp
4860 %old = cmpxchg i32* %ptr, i32 %cmp, i32 %squared <i>; yields {i32}</i>
4861 %success = <a href="#i_icmp">icmp</a> eq i32 %cmp, %old
4862 <a href="#i_br">br</a> i1 %success, label %done, label %loop
4863
4864done:
4865 ...
4866</pre>
4867
4868</div>
4869
4870<!-- _______________________________________________________________________ -->
NAKAMURA Takumib5bb29c2011-08-12 06:17:17 +0000[diff] [blame]4871<h4>
4872<a name="i_atomicrmw">'<tt>atomicrmw</tt>' Instruction</a>
4873</h4>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]4874
NAKAMURA Takumib5bb29c2011-08-12 06:17:17 +0000[diff] [blame]4875<div>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]4876
4877<h5>Syntax:</h5>
4878<pre>
Eli Friedmanf03bb262011-08-12 22:50:01 +0000[diff] [blame]4879 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]4880</pre>
4881
4882<h5>Overview:</h5>
4883<p>The '<tt>atomicrmw</tt>' instruction is used to atomically modify memory.</p>
4884
4885<h5>Arguments:</h5>
4886<p>There are three arguments to the '<code>atomicrmw</code>' instruction: an
4887operation to apply, an address whose value to modify, an argument to the
4888operation. The operation must be one of the following keywords:</p>
4889<ul>
4890 <li>xchg</li>
4891 <li>add</li>
4892 <li>sub</li>
4893 <li>and</li>
4894 <li>nand</li>
4895 <li>or</li>
4896 <li>xor</li>
4897 <li>max</li>
4898 <li>min</li>
4899 <li>umax</li>
4900 <li>umin</li>
4901</ul>
4902
4903<p>The type of '<var>&lt;value&gt;</var>' must be an integer type whose
4904bit width is a power of two greater than or equal to eight and less than
4905or equal to a target-specific size limit. The type of the
4906'<code>&lt;pointer&gt;</code>' operand must be a pointer to that type.
4907If the <code>atomicrmw</code> is marked as <code>volatile</code>, then the
4908optimizer is not allowed to modify the number or order of execution of this
4909<code>atomicrmw</code> with other <a href="#volatile">volatile
4910 operations</a>.</p>
4911
4912<!-- FIXME: Extend allowed types. -->
4913
4914<h5>Semantics:</h5>
4915<p>The contents of memory at the location specified by the
4916'<tt>&lt;pointer&gt;</tt>' operand are atomically read, modified, and written
4917back. The original value at the location is returned. The modification is
4918specified by the <var>operation</var> argument:</p>
4919
4920<ul>
4921 <li>xchg: <code>*ptr = val</code></li>
4922 <li>add: <code>*ptr = *ptr + val</code></li>
4923 <li>sub: <code>*ptr = *ptr - val</code></li>
4924 <li>and: <code>*ptr = *ptr &amp; val</code></li>
4925 <li>nand: <code>*ptr = ~(*ptr &amp; val)</code></li>
4926 <li>or: <code>*ptr = *ptr | val</code></li>
4927 <li>xor: <code>*ptr = *ptr ^ val</code></li>
4928 <li>max: <code>*ptr = *ptr &gt; val ? *ptr : val</code> (using a signed comparison)</li>
4929 <li>min: <code>*ptr = *ptr &lt; val ? *ptr : val</code> (using a signed comparison)</li>
4930 <li>umax: <code>*ptr = *ptr &gt; val ? *ptr : val</code> (using an unsigned comparison)</li>
4931 <li>umin: <code>*ptr = *ptr &lt; val ? *ptr : val</code> (using an unsigned comparison)</li>
4932</ul>
4933
4934<h5>Example:</h5>
4935<pre>
4936 %old = atomicrmw add i32* %ptr, i32 1 acquire <i>; yields {i32}</i>
4937</pre>
4938
4939</div>
4940
4941<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4942<h4>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4943 <a name="i_getelementptr">'<tt>getelementptr</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4944</h4>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4945
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4946<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4947
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]4948<h5>Syntax:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4949<pre>
Matthijs Kooijmane49d0bc2008-10-13 13:44:15 +0000[diff] [blame]4950 &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]4951 &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]4952</pre>
4953
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]4954<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4955<p>The '<tt>getelementptr</tt>' instruction is used to get the address of a
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4956 subelement of an <a href="#t_aggregate">aggregate</a> data structure.
4957 It performs address calculation only and does not access memory.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4958
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]4959<h5>Arguments:</h5>
Matthijs Kooijmane49d0bc2008-10-13 13:44:15 +0000[diff] [blame]4960<p>The first argument is always a pointer, and forms the basis of the
Chris Lattnerc8eef442009-07-29 06:44:13 +0000[diff] [blame]4961 calculation. The remaining arguments are indices that indicate which of the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4962 elements of the aggregate object are indexed. The interpretation of each
4963 index is dependent on the type being indexed into. The first index always
4964 indexes the pointer value given as the first argument, the second index
4965 indexes a value of the type pointed to (not necessarily the value directly
4966 pointed to, since the first index can be non-zero), etc. The first type
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4967 indexed into must be a pointer value, subsequent types can be arrays,
Chris Lattner61c70e92010-08-28 04:09:24 +0000[diff] [blame]4968 vectors, and structs. Note that subsequent types being indexed into
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4969 can never be pointers, since that would require loading the pointer before
4970 continuing calculation.</p>
Matthijs Kooijmane49d0bc2008-10-13 13:44:15 +0000[diff] [blame]4971
4972<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]4973 When indexing into a (optionally packed) structure, only <tt>i32</tt>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4974 integer <b>constants</b> are allowed. When indexing into an array, pointer
4975 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]4976 constant. These integers are treated as signed values where relevant.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4977
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4978<p>For example, let's consider a C code fragment and how it gets compiled to
4979 LLVM:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4980
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]4981<pre class="doc_code">
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4982struct RT {
4983 char A;
Chris Lattnercabc8462007-05-29 15:43:56 +0000[diff] [blame]4984 int B[10][20];
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4985 char C;
4986};
4987struct ST {
Chris Lattnercabc8462007-05-29 15:43:56 +0000[diff] [blame]4988 int X;
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4989 double Y;
4990 struct RT Z;
4991};
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4992
Chris Lattnercabc8462007-05-29 15:43:56 +0000[diff] [blame]4993int *foo(struct ST *s) {
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4994 return &amp;s[1].Z.B[5][13];
4995}
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4996</pre>
4997
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4998<p>The LLVM code generated by the GCC frontend is:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4999
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]5000<pre class="doc_code">
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]5001%RT = <a href="#namedtypes">type</a> { i8 , [10 x [20 x i32]], i8 }
5002%ST = <a href="#namedtypes">type</a> { i32, double, %RT }
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5003
Dan Gohman4df605b2009-07-25 02:23:48 +0000[diff] [blame]5004define i32* @foo(%ST* %s) {
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]5005entry:
5006 %reg = getelementptr %ST* %s, i32 1, i32 2, i32 1, i32 5, i32 13
5007 ret i32* %reg
5008}
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5009</pre>
5010
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]5011<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5012<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]5013 type, which is a pointer, yielding a '<tt>%ST</tt>' = '<tt>{ i32, double, %RT
5014 }</tt>' type, a structure. The second index indexes into the third element
5015 of the structure, yielding a '<tt>%RT</tt>' = '<tt>{ i8 , [10 x [20 x i32]],
5016 i8 }</tt>' type, another structure. The third index indexes into the second
5017 element of the structure, yielding a '<tt>[10 x [20 x i32]]</tt>' type, an
5018 array. The two dimensions of the array are subscripted into, yielding an
5019 '<tt>i32</tt>' type. The '<tt>getelementptr</tt>' instruction returns a
5020 pointer to this element, thus computing a value of '<tt>i32*</tt>' type.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5021
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5022<p>Note that it is perfectly legal to index partially through a structure,
5023 returning a pointer to an inner element. Because of this, the LLVM code for
5024 the given testcase is equivalent to:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5025
5026<pre>
Dan Gohman4df605b2009-07-25 02:23:48 +0000[diff] [blame]5027 define i32* @foo(%ST* %s) {
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5028 %t1 = getelementptr %ST* %s, i32 1 <i>; yields %ST*:%t1</i>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]5029 %t2 = getelementptr %ST* %t1, i32 0, i32 2 <i>; yields %RT*:%t2</i>
5030 %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]5031 %t4 = getelementptr [10 x [20 x i32]]* %t3, i32 0, i32 5 <i>; yields [20 x i32]*:%t4</i>
5032 %t5 = getelementptr [20 x i32]* %t4, i32 0, i32 13 <i>; yields i32*:%t5</i>
5033 ret i32* %t5
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5034 }
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]5035</pre>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]5036
Dan Gohmandd8004d2009-07-27 21:53:46 +0000[diff] [blame]5037<p>If the <tt>inbounds</tt> keyword is present, the result value of the
Dan Gohman27ef9972010-04-23 15:23:32 +0000[diff] [blame]5038 <tt>getelementptr</tt> is a <a href="#trapvalues">trap value</a> if the
5039 base pointer is not an <i>in bounds</i> address of an allocated object,
5040 or if any of the addresses that would be formed by successive addition of
5041 the offsets implied by the indices to the base address with infinitely
Eli Friedman266246c2011-08-12 23:37:55 +0000[diff] [blame]5042 precise signed arithmetic are not an <i>in bounds</i> address of that
5043 allocated object. The <i>in bounds</i> addresses for an allocated object
5044 are all the addresses that point into the object, plus the address one
5045 byte past the end.</p>
Dan Gohmandd8004d2009-07-27 21:53:46 +0000[diff] [blame]5046
5047<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]5048 the base address with silently-wrapping two's complement arithmetic. If the
5049 offsets have a different width from the pointer, they are sign-extended or
5050 truncated to the width of the pointer. The result value of the
5051 <tt>getelementptr</tt> may be outside the object pointed to by the base
5052 pointer. The result value may not necessarily be used to access memory
5053 though, even if it happens to point into allocated storage. See the
5054 <a href="#pointeraliasing">Pointer Aliasing Rules</a> section for more
5055 information.</p>
Dan Gohmandd8004d2009-07-27 21:53:46 +0000[diff] [blame]5056
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5057<p>The getelementptr instruction is often confusing. For some more insight into
5058 how it works, see <a href="GetElementPtr.html">the getelementptr FAQ</a>.</p>
Chris Lattner884a9702006-08-15 00:45:58 +0000[diff] [blame]5059
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]5060<h5>Example:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5061<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5062 <i>; yields [12 x i8]*:aptr</i>
Matthijs Kooijmane49d0bc2008-10-13 13:44:15 +0000[diff] [blame]5063 %aptr = getelementptr {i32, [12 x i8]}* %saptr, i64 0, i32 1
5064 <i>; yields i8*:vptr</i>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]5065 %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]5066 <i>; yields i8*:eptr</i>
5067 %eptr = getelementptr [12 x i8]* %aptr, i64 0, i32 1
Sanjiv Gupta9f805c22009-04-25 07:27:44 +0000[diff] [blame]5068 <i>; yields i32*:iptr</i>
Sanjiv Gupta16ffa802009-04-24 16:38:13 +0000[diff] [blame]5069 %iptr = getelementptr [10 x i32]* @arr, i16 0, i16 0
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5070</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5071
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5072</div>
Reid Spencer47ce1792006-11-09 21:15:49 +0000[diff] [blame]5073
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5074</div>
5075
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]5076<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5077<h3>
5078 <a name="convertops">Conversion Operations</a>
5079</h3>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5080
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5081<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5082
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5083<p>The instructions in this category are the conversion instructions (casting)
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5084 which all take a single operand and a type. They perform various bit
5085 conversions on the operand.</p>
5086
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]5087<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5088<h4>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5089 <a name="i_trunc">'<tt>trunc .. to</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5090</h4>
5091
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5092<div>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5093
5094<h5>Syntax:</h5>
5095<pre>
5096 &lt;result&gt; = trunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
5097</pre>
5098
5099<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5100<p>The '<tt>trunc</tt>' instruction truncates its operand to the
5101 type <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5102
5103<h5>Arguments:</h5>
Nadav Rotem8c20ec52011-02-24 21:01:34 +0000[diff] [blame]5104<p>The '<tt>trunc</tt>' instruction takes a value to trunc, and a type to trunc it to.
5105 Both types must be of <a href="#t_integer">integer</a> types, or vectors
5106 of the same number of integers.
5107 The bit size of the <tt>value</tt> must be larger than
5108 the bit size of the destination type, <tt>ty2</tt>.
5109 Equal sized types are not allowed.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5110
5111<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5112<p>The '<tt>trunc</tt>' instruction truncates the high order bits
5113 in <tt>value</tt> and converts the remaining bits to <tt>ty2</tt>. Since the
5114 source size must be larger than the destination size, <tt>trunc</tt> cannot
5115 be a <i>no-op cast</i>. It will always truncate bits.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5116
5117<h5>Example:</h5>
5118<pre>
Nadav Rotem8c20ec52011-02-24 21:01:34 +0000[diff] [blame]5119 %X = trunc i32 257 to i8 <i>; yields i8:1</i>
5120 %Y = trunc i32 123 to i1 <i>; yields i1:true</i>
5121 %Z = trunc i32 122 to i1 <i>; yields i1:false</i>
5122 %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]5123</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5124
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5125</div>
5126
5127<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5128<h4>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5129 <a name="i_zext">'<tt>zext .. to</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5130</h4>
5131
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5132<div>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5133
5134<h5>Syntax:</h5>
5135<pre>
5136 &lt;result&gt; = zext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
5137</pre>
5138
5139<h5>Overview:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5140<p>The '<tt>zext</tt>' instruction zero extends its operand to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5141 <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5142
5143
5144<h5>Arguments:</h5>
Nadav Rotemed9b9342011-02-20 12:37:50 +0000[diff] [blame]5145<p>The '<tt>zext</tt>' instruction takes a value to cast, and a type to cast it to.
5146 Both types must be of <a href="#t_integer">integer</a> types, or vectors
5147 of the same number of integers.
5148 The bit size of the <tt>value</tt> must be smaller than
5149 the bit size of the destination type,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5150 <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5151
5152<h5>Semantics:</h5>
5153<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]5154 bits until it reaches the size of the destination type, <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5155
Reid Spencerb5929522007-01-12 15:46:11 +0000[diff] [blame]5156<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]5157
5158<h5>Example:</h5>
5159<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5160 %X = zext i32 257 to i64 <i>; yields i64:257</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]5161 %Y = zext i1 true to i32 <i>; yields i32:1</i>
Nadav Rotemed9b9342011-02-20 12:37:50 +0000[diff] [blame]5162 %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]5163</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5164
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5165</div>
5166
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_sext">'<tt>sext .. 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; = sext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
5177</pre>
5178
5179<h5>Overview:</h5>
5180<p>The '<tt>sext</tt>' sign extends <tt>value</tt> to the type <tt>ty2</tt>.</p>
5181
5182<h5>Arguments:</h5>
Nadav Rotem8c20ec52011-02-24 21:01:34 +0000[diff] [blame]5183<p>The '<tt>sext</tt>' instruction takes a value to cast, and a type to cast it to.
5184 Both types must be of <a href="#t_integer">integer</a> types, or vectors
5185 of the same number of integers.
5186 The bit size of the <tt>value</tt> must be smaller than
5187 the bit size of the destination type,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5188 <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5189
5190<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5191<p>The '<tt>sext</tt>' instruction performs a sign extension by copying the sign
5192 bit (highest order bit) of the <tt>value</tt> until it reaches the bit size
5193 of the type <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5194
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]5195<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]5196
5197<h5>Example:</h5>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5198<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5199 %X = sext i8 -1 to i16 <i>; yields i16 :65535</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]5200 %Y = sext i1 true to i32 <i>; yields i32:-1</i>
Nadav Rotem8c20ec52011-02-24 21:01:34 +0000[diff] [blame]5201 %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]5202</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5203
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5204</div>
5205
5206<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5207<h4>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]5208 <a name="i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5209</h4>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]5210
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5211<div>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]5212
5213<h5>Syntax:</h5>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]5214<pre>
5215 &lt;result&gt; = fptrunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
5216</pre>
5217
5218<h5>Overview:</h5>
5219<p>The '<tt>fptrunc</tt>' instruction truncates <tt>value</tt> to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5220 <tt>ty2</tt>.</p>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]5221
5222<h5>Arguments:</h5>
5223<p>The '<tt>fptrunc</tt>' instruction takes a <a href="#t_floating">floating
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5224 point</a> value to cast and a <a href="#t_floating">floating point</a> type
5225 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]5226 <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]5227 <i>no-op cast</i>.</p>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]5228
5229<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5230<p>The '<tt>fptrunc</tt>' instruction truncates a <tt>value</tt> from a larger
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5231 <a href="#t_floating">floating point</a> type to a smaller
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5232 <a href="#t_floating">floating point</a> type. If the value cannot fit
5233 within the destination type, <tt>ty2</tt>, then the results are
5234 undefined.</p>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]5235
5236<h5>Example:</h5>
5237<pre>
5238 %X = fptrunc double 123.0 to float <i>; yields float:123.0</i>
5239 %Y = fptrunc double 1.0E+300 to float <i>; yields undefined</i>
5240</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5241
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]5242</div>
5243
5244<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5245<h4>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5246 <a name="i_fpext">'<tt>fpext .. to</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5247</h4>
5248
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5249<div>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5250
5251<h5>Syntax:</h5>
5252<pre>
5253 &lt;result&gt; = fpext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
5254</pre>
5255
5256<h5>Overview:</h5>
5257<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]5258 floating point value.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5259
5260<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5261<p>The '<tt>fpext</tt>' instruction takes a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5262 <a href="#t_floating">floating point</a> <tt>value</tt> to cast, and
5263 a <a href="#t_floating">floating point</a> type to cast it to. The source
5264 type must be smaller than the destination type.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5265
5266<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]5267<p>The '<tt>fpext</tt>' instruction extends the <tt>value</tt> from a smaller
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5268 <a href="#t_floating">floating point</a> type to a larger
5269 <a href="#t_floating">floating point</a> type. The <tt>fpext</tt> cannot be
5270 used to make a <i>no-op cast</i> because it always changes bits. Use
5271 <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]5272
5273<h5>Example:</h5>
5274<pre>
Nick Lewycky5bb3ece2011-03-31 18:20:19 +0000[diff] [blame]5275 %X = fpext float 3.125 to double <i>; yields double:3.125000e+00</i>
5276 %Y = fpext double %X to fp128 <i>; yields fp128:0xL00000000000000004000900000000000</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5277</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5278
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5279</div>
5280
5281<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5282<h4>
Reid Spencer24d6da52007-01-21 00:29:26 +0000[diff] [blame]5283 <a name="i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5284</h4>
5285
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5286<div>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5287
5288<h5>Syntax:</h5>
5289<pre>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]5290 &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]5291</pre>
5292
5293<h5>Overview:</h5>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]5294<p>The '<tt>fptoui</tt>' converts a floating point <tt>value</tt> to its
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5295 unsigned integer equivalent of type <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5296
5297<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5298<p>The '<tt>fptoui</tt>' instruction takes a value to cast, which must be a
5299 scalar or vector <a href="#t_floating">floating point</a> value, and a type
5300 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
5301 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
5302 vector integer type with the same number of elements as <tt>ty</tt></p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5303
5304<h5>Semantics:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5305<p>The '<tt>fptoui</tt>' instruction converts its
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5306 <a href="#t_floating">floating point</a> operand into the nearest (rounding
5307 towards zero) unsigned integer value. If the value cannot fit
5308 in <tt>ty2</tt>, the results are undefined.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5309
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5310<h5>Example:</h5>
5311<pre>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]5312 %X = fptoui double 123.0 to i32 <i>; yields i32:123</i>
Chris Lattner88519042007-09-22 03:17:52 +0000[diff] [blame]5313 %Y = fptoui float 1.0E+300 to i1 <i>; yields undefined:1</i>
Gabor Greif6a292012009-10-28 09:21:30 +0000[diff] [blame]5314 %Z = fptoui float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5315</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5316
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5317</div>
5318
5319<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5320<h4>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]5321 <a name="i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5322</h4>
5323
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5324<div>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5325
5326<h5>Syntax:</h5>
5327<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]5328 &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]5329</pre>
5330
5331<h5>Overview:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5332<p>The '<tt>fptosi</tt>' instruction converts
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5333 <a href="#t_floating">floating point</a> <tt>value</tt> to
5334 type <tt>ty2</tt>.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5335
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]5336<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5337<p>The '<tt>fptosi</tt>' instruction takes a value to cast, which must be a
5338 scalar or vector <a href="#t_floating">floating point</a> value, and a type
5339 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
5340 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
5341 vector integer type with the same number of elements as <tt>ty</tt></p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5342
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]5343<h5>Semantics:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5344<p>The '<tt>fptosi</tt>' instruction converts its
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5345 <a href="#t_floating">floating point</a> operand into the nearest (rounding
5346 towards zero) signed integer value. If the value cannot fit in <tt>ty2</tt>,
5347 the results are undefined.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5348
Chris Lattner33ba0d92001-07-09 00:26:23 +0000[diff] [blame]5349<h5>Example:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5350<pre>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]5351 %X = fptosi double -123.0 to i32 <i>; yields i32:-123</i>
Chris Lattner88519042007-09-22 03:17:52 +0000[diff] [blame]5352 %Y = fptosi float 1.0E-247 to i1 <i>; yields undefined:1</i>
Gabor Greif6a292012009-10-28 09:21:30 +0000[diff] [blame]5353 %Z = fptosi float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5354</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5355
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5356</div>
5357
5358<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5359<h4>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]5360 <a name="i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5361</h4>
5362
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5363<div>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5364
5365<h5>Syntax:</h5>
5366<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]5367 &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]5368</pre>
5369
5370<h5>Overview:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]5371<p>The '<tt>uitofp</tt>' instruction regards <tt>value</tt> as an unsigned
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5372 integer and converts that value to the <tt>ty2</tt> type.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5373
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5374<h5>Arguments:</h5>
Nate Begemanb348d182007-11-17 03:58:34 +0000[diff] [blame]5375<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]5376 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
5377 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
5378 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
5379 floating point type with the same number of elements as <tt>ty</tt></p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5380
5381<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]5382<p>The '<tt>uitofp</tt>' instruction interprets its operand as an unsigned
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5383 integer quantity and converts it to the corresponding floating point
5384 value. If the value cannot fit in the floating point value, the results are
5385 undefined.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5386
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5387<h5>Example:</h5>
5388<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5389 %X = uitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]5390 %Y = uitofp i8 -1 to double <i>; yields double:255.0</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5391</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5392
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5393</div>
5394
5395<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5396<h4>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]5397 <a name="i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5398</h4>
5399
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5400<div>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5401
5402<h5>Syntax:</h5>
5403<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]5404 &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]5405</pre>
5406
5407<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5408<p>The '<tt>sitofp</tt>' instruction regards <tt>value</tt> as a signed integer
5409 and converts that value to the <tt>ty2</tt> type.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5410
5411<h5>Arguments:</h5>
Nate Begemanb348d182007-11-17 03:58:34 +0000[diff] [blame]5412<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]5413 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
5414 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
5415 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
5416 floating point type with the same number of elements as <tt>ty</tt></p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5417
5418<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5419<p>The '<tt>sitofp</tt>' instruction interprets its operand as a signed integer
5420 quantity and converts it to the corresponding floating point value. If the
5421 value cannot fit in the floating point value, the results are undefined.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5422
5423<h5>Example:</h5>
5424<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5425 %X = sitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]5426 %Y = sitofp i8 -1 to double <i>; yields double:-1.0</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5427</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5428
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5429</div>
5430
5431<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5432<h4>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]5433 <a name="i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5434</h4>
5435
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5436<div>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]5437
5438<h5>Syntax:</h5>
5439<pre>
5440 &lt;result&gt; = ptrtoint &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
5441</pre>
5442
5443<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5444<p>The '<tt>ptrtoint</tt>' instruction converts the pointer <tt>value</tt> to
5445 the integer type <tt>ty2</tt>.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]5446
5447<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5448<p>The '<tt>ptrtoint</tt>' instruction takes a <tt>value</tt> to cast, which
5449 must be a <a href="#t_pointer">pointer</a> value, and a type to cast it to
5450 <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]5451
5452<h5>Semantics:</h5>
5453<p>The '<tt>ptrtoint</tt>' instruction converts <tt>value</tt> to integer type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5454 <tt>ty2</tt> by interpreting the pointer value as an integer and either
5455 truncating or zero extending that value to the size of the integer type. If
5456 <tt>value</tt> is smaller than <tt>ty2</tt> then a zero extension is done. If
5457 <tt>value</tt> is larger than <tt>ty2</tt> then a truncation is done. If they
5458 are the same size, then nothing is done (<i>no-op cast</i>) other than a type
5459 change.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]5460
5461<h5>Example:</h5>
5462<pre>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5463 %X = ptrtoint i32* %X to i8 <i>; yields truncation on 32-bit architecture</i>
5464 %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]5465</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5466
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]5467</div>
5468
5469<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5470<h4>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]5471 <a name="i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5472</h4>
5473
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5474<div>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]5475
5476<h5>Syntax:</h5>
5477<pre>
5478 &lt;result&gt; = inttoptr &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
5479</pre>
5480
5481<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5482<p>The '<tt>inttoptr</tt>' instruction converts an integer <tt>value</tt> to a
5483 pointer type, <tt>ty2</tt>.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]5484
5485<h5>Arguments:</h5>
Duncan Sands8036ca42007-03-30 12:22:09 +0000[diff] [blame]5486<p>The '<tt>inttoptr</tt>' instruction takes an <a href="#t_integer">integer</a>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5487 value to cast, and a type to cast it to, which must be a
5488 <a href="#t_pointer">pointer</a> type.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]5489
5490<h5>Semantics:</h5>
5491<p>The '<tt>inttoptr</tt>' instruction converts <tt>value</tt> to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5492 <tt>ty2</tt> by applying either a zero extension or a truncation depending on
5493 the size of the integer <tt>value</tt>. If <tt>value</tt> is larger than the
5494 size of a pointer then a truncation is done. If <tt>value</tt> is smaller
5495 than the size of a pointer then a zero extension is done. If they are the
5496 same size, nothing is done (<i>no-op cast</i>).</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]5497
5498<h5>Example:</h5>
5499<pre>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5500 %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]5501 %Y = inttoptr i32 255 to i32* <i>; yields no-op on 32-bit architecture</i>
5502 %Z = inttoptr i64 0 to i32* <i>; yields truncation on 32-bit architecture</i>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]5503</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5504
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]5505</div>
5506
5507<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5508<h4>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]5509 <a name="i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5510</h4>
5511
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5512<div>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5513
5514<h5>Syntax:</h5>
5515<pre>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]5516 &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]5517</pre>
5518
5519<h5>Overview:</h5>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]5520<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5521 <tt>ty2</tt> without changing any bits.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5522
5523<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5524<p>The '<tt>bitcast</tt>' instruction takes a value to cast, which must be a
5525 non-aggregate first class value, and a type to cast it to, which must also be
5526 a non-aggregate <a href="#t_firstclass">first class</a> type. The bit sizes
5527 of <tt>value</tt> and the destination type, <tt>ty2</tt>, must be
5528 identical. If the source type is a pointer, the destination type must also be
5529 a pointer. This instruction supports bitwise conversion of vectors to
5530 integers and to vectors of other types (as long as they have the same
5531 size).</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5532
5533<h5>Semantics:</h5>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]5534<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5535 <tt>ty2</tt>. It is always a <i>no-op cast</i> because no bits change with
5536 this conversion. The conversion is done as if the <tt>value</tt> had been
5537 stored to memory and read back as type <tt>ty2</tt>. Pointer types may only
5538 be converted to other pointer types with this instruction. To convert
5539 pointers to other types, use the <a href="#i_inttoptr">inttoptr</a> or
5540 <a href="#i_ptrtoint">ptrtoint</a> instructions first.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5541
5542<h5>Example:</h5>
5543<pre>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5544 %X = bitcast i8 255 to i8 <i>; yields i8 :-1</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5545 %Y = bitcast i32* %x to sint* <i>; yields sint*:%x</i>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5546 %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]5547</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5548
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5549</div>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5550
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5551</div>
5552
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5553<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5554<h3>
5555 <a name="otherops">Other Operations</a>
5556</h3>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5557
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5558<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5559
5560<p>The instructions in this category are the "miscellaneous" instructions, which
5561 defy better classification.</p>
5562
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5563<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5564<h4>
5565 <a name="i_icmp">'<tt>icmp</tt>' Instruction</a>
5566</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5567
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5568<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5569
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5570<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5571<pre>
5572 &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]5573</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5574
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5575<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5576<p>The '<tt>icmp</tt>' instruction returns a boolean value or a vector of
5577 boolean values based on comparison of its two integer, integer vector, or
5578 pointer operands.</p>
5579
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5580<h5>Arguments:</h5>
5581<p>The '<tt>icmp</tt>' instruction takes three operands. The first operand is
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5582 the condition code indicating the kind of comparison to perform. It is not a
5583 value, just a keyword. The possible condition code are:</p>
5584
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5585<ol>
5586 <li><tt>eq</tt>: equal</li>
5587 <li><tt>ne</tt>: not equal </li>
5588 <li><tt>ugt</tt>: unsigned greater than</li>
5589 <li><tt>uge</tt>: unsigned greater or equal</li>
5590 <li><tt>ult</tt>: unsigned less than</li>
5591 <li><tt>ule</tt>: unsigned less or equal</li>
5592 <li><tt>sgt</tt>: signed greater than</li>
5593 <li><tt>sge</tt>: signed greater or equal</li>
5594 <li><tt>slt</tt>: signed less than</li>
5595 <li><tt>sle</tt>: signed less or equal</li>
5596</ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5597
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]5598<p>The remaining two arguments must be <a href="#t_integer">integer</a> or
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5599 <a href="#t_pointer">pointer</a> or integer <a href="#t_vector">vector</a>
5600 typed. They must also be identical types.</p>
5601
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5602<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5603<p>The '<tt>icmp</tt>' compares <tt>op1</tt> and <tt>op2</tt> according to the
5604 condition code given as <tt>cond</tt>. The comparison performed always yields
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]5605 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]5606 result, as follows:</p>
5607
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5608<ol>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5609 <li><tt>eq</tt>: yields <tt>true</tt> if the operands are equal,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5610 <tt>false</tt> otherwise. No sign interpretation is necessary or
5611 performed.</li>
5612
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5613 <li><tt>ne</tt>: yields <tt>true</tt> if the operands are unequal,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5614 <tt>false</tt> otherwise. No sign interpretation is necessary or
5615 performed.</li>
5616
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5617 <li><tt>ugt</tt>: interprets the operands as unsigned values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5618 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
5619
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5620 <li><tt>uge</tt>: interprets the operands as unsigned values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5621 <tt>true</tt> if <tt>op1</tt> is greater than or equal
5622 to <tt>op2</tt>.</li>
5623
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5624 <li><tt>ult</tt>: interprets the operands as unsigned values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5625 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
5626
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5627 <li><tt>ule</tt>: interprets the operands as unsigned values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5628 <tt>true</tt> if <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
5629
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5630 <li><tt>sgt</tt>: interprets the operands as signed values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5631 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
5632
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5633 <li><tt>sge</tt>: interprets the operands as signed values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5634 <tt>true</tt> if <tt>op1</tt> is greater than or equal
5635 to <tt>op2</tt>.</li>
5636
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5637 <li><tt>slt</tt>: interprets the operands as signed values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5638 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
5639
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5640 <li><tt>sle</tt>: interprets the operands as signed values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5641 <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]5642</ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5643
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5644<p>If the operands are <a href="#t_pointer">pointer</a> typed, the pointer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5645 values are compared as if they were integers.</p>
5646
5647<p>If the operands are integer vectors, then they are compared element by
5648 element. The result is an <tt>i1</tt> vector with the same number of elements
5649 as the values being compared. Otherwise, the result is an <tt>i1</tt>.</p>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5650
5651<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5652<pre>
5653 &lt;result&gt; = icmp eq i32 4, 5 <i>; yields: result=false</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5654 &lt;result&gt; = icmp ne float* %X, %X <i>; yields: result=false</i>
5655 &lt;result&gt; = icmp ult i16 4, 5 <i>; yields: result=true</i>
5656 &lt;result&gt; = icmp sgt i16 4, 5 <i>; yields: result=false</i>
5657 &lt;result&gt; = icmp ule i16 -4, 5 <i>; yields: result=false</i>
5658 &lt;result&gt; = icmp sge i16 4, 5 <i>; yields: result=false</i>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5659</pre>
Dan Gohmanc766f722009-01-22 01:39:38 +0000[diff] [blame]5660
5661<p>Note that the code generator does not yet support vector types with
5662 the <tt>icmp</tt> instruction.</p>
5663
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5664</div>
5665
5666<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5667<h4>
5668 <a name="i_fcmp">'<tt>fcmp</tt>' Instruction</a>
5669</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5670
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5671<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5672
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5673<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5674<pre>
5675 &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]5676</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5677
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5678<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5679<p>The '<tt>fcmp</tt>' instruction returns a boolean value or vector of boolean
5680 values based on comparison of its operands.</p>
5681
5682<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]5683(<a href="#t_integer"><tt>i1</tt></a>).</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5684
5685<p>If the operands are floating point vectors, then the result type is a vector
5686 of boolean with the same number of elements as the operands being
5687 compared.</p>
5688
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5689<h5>Arguments:</h5>
5690<p>The '<tt>fcmp</tt>' instruction takes three operands. The first operand is
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5691 the condition code indicating the kind of comparison to perform. It is not a
5692 value, just a keyword. The possible condition code are:</p>
5693
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5694<ol>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]5695 <li><tt>false</tt>: no comparison, always returns false</li>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5696 <li><tt>oeq</tt>: ordered and equal</li>
5697 <li><tt>ogt</tt>: ordered and greater than </li>
5698 <li><tt>oge</tt>: ordered and greater than or equal</li>
5699 <li><tt>olt</tt>: ordered and less than </li>
5700 <li><tt>ole</tt>: ordered and less than or equal</li>
5701 <li><tt>one</tt>: ordered and not equal</li>
5702 <li><tt>ord</tt>: ordered (no nans)</li>
5703 <li><tt>ueq</tt>: unordered or equal</li>
5704 <li><tt>ugt</tt>: unordered or greater than </li>
5705 <li><tt>uge</tt>: unordered or greater than or equal</li>
5706 <li><tt>ult</tt>: unordered or less than </li>
5707 <li><tt>ule</tt>: unordered or less than or equal</li>
5708 <li><tt>une</tt>: unordered or not equal</li>
5709 <li><tt>uno</tt>: unordered (either nans)</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]5710 <li><tt>true</tt>: no comparison, always returns true</li>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5711</ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5712
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5713<p><i>Ordered</i> means that neither operand is a QNAN while
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5714 <i>unordered</i> means that either operand may be a QNAN.</p>
5715
5716<p>Each of <tt>val1</tt> and <tt>val2</tt> arguments must be either
5717 a <a href="#t_floating">floating point</a> type or
5718 a <a href="#t_vector">vector</a> of floating point type. They must have
5719 identical types.</p>
5720
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5721<h5>Semantics:</h5>
Gabor Greiffb224a22008-08-07 21:46:00 +0000[diff] [blame]5722<p>The '<tt>fcmp</tt>' instruction compares <tt>op1</tt> and <tt>op2</tt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5723 according to the condition code given as <tt>cond</tt>. If the operands are
5724 vectors, then the vectors are compared element by element. Each comparison
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]5725 performed always yields an <a href="#t_integer">i1</a> result, as
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5726 follows:</p>
5727
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5728<ol>
5729 <li><tt>false</tt>: always yields <tt>false</tt>, regardless of operands.</li>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5730
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5731 <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]5732 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
5733
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]5734 <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]5735 <tt>op1</tt> is greater than <tt>op2</tt>.</li>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5736
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5737 <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]5738 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
5739
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5740 <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]5741 <tt>op1</tt> is less than <tt>op2</tt>.</li>
5742
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5743 <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]5744 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
5745
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5746 <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]5747 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
5748
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]5749 <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]5750
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5751 <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]5752 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
5753
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5754 <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]5755 <tt>op1</tt> is greater than <tt>op2</tt>.</li>
5756
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5757 <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]5758 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
5759
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5760 <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]5761 <tt>op1</tt> is less than <tt>op2</tt>.</li>
5762
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5763 <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]5764 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
5765
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5766 <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]5767 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
5768
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]5769 <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]5770
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5771 <li><tt>true</tt>: always yields <tt>true</tt>, regardless of operands.</li>
5772</ol>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5773
5774<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5775<pre>
5776 &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]5777 &lt;result&gt; = fcmp one float 4.0, 5.0 <i>; yields: result=true</i>
5778 &lt;result&gt; = fcmp olt float 4.0, 5.0 <i>; yields: result=true</i>
5779 &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]5780</pre>
Dan Gohmanc766f722009-01-22 01:39:38 +0000[diff] [blame]5781
5782<p>Note that the code generator does not yet support vector types with
5783 the <tt>fcmp</tt> instruction.</p>
5784
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5785</div>
5786
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5787<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5788<h4>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5789 <a name="i_phi">'<tt>phi</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5790</h4>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5791
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5792<div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5793
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5794<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5795<pre>
5796 &lt;result&gt; = phi &lt;ty&gt; [ &lt;val0&gt;, &lt;label0&gt;], ...
5797</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5798
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5799<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5800<p>The '<tt>phi</tt>' instruction is used to implement the &#966; node in the
5801 SSA graph representing the function.</p>
5802
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5803<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5804<p>The type of the incoming values is specified with the first type field. After
5805 this, the '<tt>phi</tt>' instruction takes a list of pairs as arguments, with
5806 one pair for each predecessor basic block of the current block. Only values
5807 of <a href="#t_firstclass">first class</a> type may be used as the value
5808 arguments to the PHI node. Only labels may be used as the label
5809 arguments.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5810
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5811<p>There must be no non-phi instructions between the start of a basic block and
5812 the PHI instructions: i.e. PHI instructions must be first in a basic
5813 block.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5814
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5815<p>For the purposes of the SSA form, the use of each incoming value is deemed to
5816 occur on the edge from the corresponding predecessor block to the current
5817 block (but after any definition of an '<tt>invoke</tt>' instruction's return
5818 value on the same edge).</p>
Jay Foadd2449092009-06-03 10:20:10 +0000[diff] [blame]5819
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5820<h5>Semantics:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5821<p>At runtime, the '<tt>phi</tt>' instruction logically takes on the value
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5822 specified by the pair corresponding to the predecessor basic block that
5823 executed just prior to the current block.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5824
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5825<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5826<pre>
5827Loop: ; Infinite loop that counts from 0 on up...
5828 %indvar = phi i32 [ 0, %LoopHeader ], [ %nextindvar, %Loop ]
5829 %nextindvar = add i32 %indvar, 1
5830 br label %Loop
5831</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5832
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5833</div>
5834
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5835<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5836<h4>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5837 <a name="i_select">'<tt>select</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5838</h4>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5839
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5840<div>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5841
5842<h5>Syntax:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5843<pre>
Dan Gohmanf72fb672008-09-09 01:02:47 +0000[diff] [blame]5844 &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>
5845
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]5846 <i>selty</i> is either i1 or {&lt;N x i1&gt;}
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5847</pre>
5848
5849<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5850<p>The '<tt>select</tt>' instruction is used to choose one value based on a
5851 condition, without branching.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5852
5853
5854<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5855<p>The '<tt>select</tt>' instruction requires an 'i1' value or a vector of 'i1'
5856 values indicating the condition, and two values of the
5857 same <a href="#t_firstclass">first class</a> type. If the val1/val2 are
5858 vectors and the condition is a scalar, then entire vectors are selected, not
5859 individual elements.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5860
5861<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5862<p>If the condition is an i1 and it evaluates to 1, the instruction returns the
5863 first value argument; otherwise, it returns the second value argument.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5864
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5865<p>If the condition is a vector of i1, then the value arguments must be vectors
5866 of the same size, and the selection is done element by element.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5867
5868<h5>Example:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5869<pre>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]5870 %X = select i1 true, i8 17, i8 42 <i>; yields i8:17</i>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5871</pre>
Dan Gohmanc766f722009-01-22 01:39:38 +0000[diff] [blame]5872
5873<p>Note that the code generator does not yet support conditions
5874 with vector type.</p>
5875
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5876</div>
5877
Robert Bocchino05ccd702006-01-15 20:48:27 +0000[diff] [blame]5878<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5879<h4>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5880 <a name="i_call">'<tt>call</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5881</h4>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5882
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5883<div>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5884
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]5885<h5>Syntax:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5886<pre>
Devang Patel307e8ab2008-10-07 17:48:33 +0000[diff] [blame]5887 &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]5888</pre>
5889
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]5890<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5891<p>The '<tt>call</tt>' instruction represents a simple function call.</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5892
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]5893<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5894<p>This instruction requires several arguments:</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5895
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]5896<ol>
Jeffrey Yasskin95fa80a2010-01-09 19:44:16 +0000[diff] [blame]5897 <li>The optional "tail" marker indicates that the callee function does not
5898 access any allocas or varargs in the caller. Note that calls may be
5899 marked "tail" even if they do not occur before
5900 a <a href="#i_ret"><tt>ret</tt></a> instruction. If the "tail" marker is
5901 present, the function call is eligible for tail call optimization,
5902 but <a href="CodeGenerator.html#tailcallopt">might not in fact be
Evan Chengdc444e92010-03-08 21:05:02 +0000[diff] [blame]5903 optimized into a jump</a>. The code generator may optimize calls marked
5904 "tail" with either 1) automatic <a href="CodeGenerator.html#sibcallopt">
5905 sibling call optimization</a> when the caller and callee have
5906 matching signatures, or 2) forced tail call optimization when the
5907 following extra requirements are met:
Jeffrey Yasskin95fa80a2010-01-09 19:44:16 +0000[diff] [blame]5908 <ul>
5909 <li>Caller and callee both have the calling
5910 convention <tt>fastcc</tt>.</li>
5911 <li>The call is in tail position (ret immediately follows call and ret
5912 uses value of call or is void).</li>
5913 <li>Option <tt>-tailcallopt</tt> is enabled,
Dan Gohmanfbbee8d2010-03-02 01:08:11 +0000[diff] [blame]5914 or <code>llvm::GuaranteedTailCallOpt</code> is <code>true</code>.</li>
Jeffrey Yasskin95fa80a2010-01-09 19:44:16 +0000[diff] [blame]5915 <li><a href="CodeGenerator.html#tailcallopt">Platform specific
5916 constraints are met.</a></li>
5917 </ul>
5918 </li>
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]5919
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5920 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
5921 convention</a> the call should use. If none is specified, the call
Jeffrey Yasskin95fa80a2010-01-09 19:44:16 +0000[diff] [blame]5922 defaults to using C calling conventions. The calling convention of the
5923 call must match the calling convention of the target function, or else the
5924 behavior is undefined.</li>
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]5925
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5926 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
5927 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
5928 '<tt>inreg</tt>' attributes are valid here.</li>
5929
5930 <li>'<tt>ty</tt>': the type of the call instruction itself which is also the
5931 type of the return value. Functions that return no value are marked
5932 <tt><a href="#t_void">void</a></tt>.</li>
5933
5934 <li>'<tt>fnty</tt>': shall be the signature of the pointer to function value
5935 being invoked. The argument types must match the types implied by this
5936 signature. This type can be omitted if the function is not varargs and if
5937 the function type does not return a pointer to a function.</li>
5938
5939 <li>'<tt>fnptrval</tt>': An LLVM value containing a pointer to a function to
5940 be invoked. In most cases, this is a direct function invocation, but
5941 indirect <tt>call</tt>s are just as possible, calling an arbitrary pointer
5942 to function value.</li>
5943
5944 <li>'<tt>function args</tt>': argument list whose types match the function
Chris Lattner0724fbd2010-03-02 06:36:51 +0000[diff] [blame]5945 signature argument types and parameter attributes. All arguments must be
5946 of <a href="#t_firstclass">first class</a> type. If the function
5947 signature indicates the function accepts a variable number of arguments,
5948 the extra arguments can be specified.</li>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5949
5950 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
5951 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
5952 '<tt>readnone</tt>' attributes are valid here.</li>
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]5953</ol>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5954
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]5955<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5956<p>The '<tt>call</tt>' instruction is used to cause control flow to transfer to
5957 a specified function, with its incoming arguments bound to the specified
5958 values. Upon a '<tt><a href="#i_ret">ret</a></tt>' instruction in the called
5959 function, control flow continues with the instruction after the function
5960 call, and the return value of the function is bound to the result
5961 argument.</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5962
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]5963<h5>Example:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5964<pre>
Nick Lewyckydb7e3c92007-09-08 13:57:50 +0000[diff] [blame]5965 %retval = call i32 @test(i32 %argc)
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]5966 call i32 (i8*, ...)* @printf(i8* %msg, i32 12, i8 42) <i>; yields i32</i>
Chris Lattner772fccf2008-03-21 17:24:17 +0000[diff] [blame]5967 %X = tail call i32 @foo() <i>; yields i32</i>
5968 %Y = tail call <a href="#callingconv">fastcc</a> i32 @foo() <i>; yields i32</i>
5969 call void %foo(i8 97 signext)
Devang Patelc3fc6df2008-03-10 20:49:15 +0000[diff] [blame]5970
5971 %struct.A = type { i32, i8 }
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]5972 %r = call %struct.A @foo() <i>; yields { 32, i8 }</i>
Dan Gohmanb1e6b962008-10-04 19:00:07 +0000[diff] [blame]5973 %gr = extractvalue %struct.A %r, 0 <i>; yields i32</i>
5974 %gr1 = extractvalue %struct.A %r, 1 <i>; yields i8</i>
Chris Lattner85a350f2008-10-08 06:26:11 +0000[diff] [blame]5975 %Z = call void @foo() noreturn <i>; indicates that %foo never returns normally</i>
Matthijs Kooijmancb73d192008-10-07 10:03:45 +0000[diff] [blame]5976 %ZZ = call zeroext i32 @bar() <i>; Return value is %zero extended</i>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5977</pre>
5978
Dale Johannesen07de8d12009-09-24 18:38:21 +0000[diff] [blame]5979<p>llvm treats calls to some functions with names and arguments that match the
Dale Johannesen9f8380b2009-09-25 17:04:42 +0000[diff] [blame]5980standard C99 library as being the C99 library functions, and may perform
5981optimizations or generate code for them under that assumption. This is
5982something we'd like to change in the future to provide better support for
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]5983freestanding environments and non-C-based languages.</p>
Dale Johannesen07de8d12009-09-24 18:38:21 +0000[diff] [blame]5984
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5985</div>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5986
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5987<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5988<h4>
Chris Lattnerfb6977d2006-01-13 23:26:01 +0000[diff] [blame]5989 <a name="i_va_arg">'<tt>va_arg</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5990</h4>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5991
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5992<div>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5993
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]5994<h5>Syntax:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5995<pre>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]5996 &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]5997</pre>
5998
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]5999<h5>Overview:</h5>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]6000<p>The '<tt>va_arg</tt>' instruction is used to access arguments passed through
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6001 the "variable argument" area of a function call. It is used to implement the
6002 <tt>va_arg</tt> macro in C.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]6003
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]6004<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6005<p>This instruction takes a <tt>va_list*</tt> value and the type of the
6006 argument. It returns a value of the specified argument type and increments
6007 the <tt>va_list</tt> to point to the next argument. The actual type
6008 of <tt>va_list</tt> is target specific.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]6009
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]6010<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6011<p>The '<tt>va_arg</tt>' instruction loads an argument of the specified type
6012 from the specified <tt>va_list</tt> and causes the <tt>va_list</tt> to point
6013 to the next argument. For more information, see the variable argument
6014 handling <a href="#int_varargs">Intrinsic Functions</a>.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]6015
6016<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]6017 take a variable number of arguments, for example, the <tt>vfprintf</tt>
6018 function.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]6019
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6020<p><tt>va_arg</tt> is an LLVM instruction instead of
6021 an <a href="#intrinsics">intrinsic function</a> because it takes a type as an
6022 argument.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]6023
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]6024<h5>Example:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]6025<p>See the <a href="#int_varargs">variable argument processing</a> section.</p>
6026
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6027<p>Note that the code generator does not yet fully support va_arg on many
6028 targets. Also, it does not currently support va_arg with aggregate types on
6029 any target.</p>
Dan Gohmanf3e60bd2009-01-12 23:12:39 +0000[diff] [blame]6030
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]6031</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6032
Bill Wendlingf78faf82011-08-02 21:52:38 +0000[diff] [blame]6033<!-- _______________________________________________________________________ -->
6034<h4>
6035 <a name="i_landingpad">'<tt>landingpad</tt>' Instruction</a>
6036</h4>
6037
6038<div>
6039
6040<h5>Syntax:</h5>
6041<pre>
Bill Wendlingbf13ee12011-08-08 08:06:05 +0000[diff] [blame]6042 &lt;resultval&gt; = landingpad &lt;somety&gt; personality &lt;type&gt; &lt;pers_fn&gt; &lt;clause&gt;+
6043 &lt;resultval&gt; = landingpad &lt;somety&gt; personality &lt;type&gt; &lt;pers_fn&gt; cleanup &lt;clause&gt;*
6044
Bill Wendlingf78faf82011-08-02 21:52:38 +0000[diff] [blame]6045 &lt;clause&gt; := catch &lt;type&gt; &lt;value&gt;
Bill Wendlinge6e88262011-08-12 20:24:12 +0000[diff] [blame]6046 &lt;clause&gt; := filter &lt;array constant type&gt; &lt;array constant&gt;
Bill Wendlingf78faf82011-08-02 21:52:38 +0000[diff] [blame]6047</pre>
6048
6049<h5>Overview:</h5>
6050<p>The '<tt>landingpad</tt>' instruction is used by
6051 <a href="ExceptionHandling.html#overview">LLVM's exception handling
6052 system</a> to specify that a basic block is a landing pad &mdash; one where
6053 the exception lands, and corresponds to the code found in the
6054 <i><tt>catch</tt></i> portion of a <i><tt>try/catch</tt></i> sequence. It
6055 defines values supplied by the personality function (<tt>pers_fn</tt>) upon
6056 re-entry to the function. The <tt>resultval</tt> has the
6057 type <tt>somety</tt>.</p>
6058
6059<h5>Arguments:</h5>
6060<p>This instruction takes a <tt>pers_fn</tt> value. This is the personality
6061 function associated with the unwinding mechanism. The optional
6062 <tt>cleanup</tt> flag indicates that the landing pad block is a cleanup.</p>
6063
6064<p>A <tt>clause</tt> begins with the clause type &mdash; <tt>catch</tt>
Bill Wendlinge6e88262011-08-12 20:24:12 +0000[diff] [blame]6065 or <tt>filter</tt> &mdash; and contains the global variable representing the
6066 "type" that may be caught or filtered respectively. Unlike the
6067 <tt>catch</tt> clause, the <tt>filter</tt> clause takes an array constant as
6068 its argument. Use "<tt>[0 x i8**] undef</tt>" for a filter which cannot
6069 throw. The '<tt>landingpad</tt>' instruction must contain <em>at least</em>
Bill Wendlingf78faf82011-08-02 21:52:38 +0000[diff] [blame]6070 one <tt>clause</tt> or the <tt>cleanup</tt> flag.</p>
6071
6072<h5>Semantics:</h5>
6073<p>The '<tt>landingpad</tt>' instruction defines the values which are set by the
6074 personality function (<tt>pers_fn</tt>) upon re-entry to the function, and
6075 therefore the "result type" of the <tt>landingpad</tt> instruction. As with
6076 calling conventions, how the personality function results are represented in
6077 LLVM IR is target specific.</p>
6078
Bill Wendlingb7a01352011-08-03 17:17:06 +0000[diff] [blame]6079<p>The clauses are applied in order from top to bottom. If two
6080 <tt>landingpad</tt> instructions are merged together through inlining, the
Bill Wendling2905c322011-08-08 07:58:58 +0000[diff] [blame]6081 clauses from the calling function are appended to the list of clauses.</p>
Bill Wendlingb7a01352011-08-03 17:17:06 +0000[diff] [blame]6082
Bill Wendlingf78faf82011-08-02 21:52:38 +0000[diff] [blame]6083<p>The <tt>landingpad</tt> instruction has several restrictions:</p>
6084
6085<ul>
6086 <li>A landing pad block is a basic block which is the unwind destination of an
6087 '<tt>invoke</tt>' instruction.</li>
6088 <li>A landing pad block must have a '<tt>landingpad</tt>' instruction as its
6089 first non-PHI instruction.</li>
6090 <li>There can be only one '<tt>landingpad</tt>' instruction within the landing
6091 pad block.</li>
6092 <li>A basic block that is not a landing pad block may not include a
6093 '<tt>landingpad</tt>' instruction.</li>
6094 <li>All '<tt>landingpad</tt>' instructions in a function must have the same
6095 personality function.</li>
6096</ul>
6097
6098<h5>Example:</h5>
6099<pre>
6100 ;; A landing pad which can catch an integer.
6101 %res = landingpad { i8*, i32 } personality i32 (...)* @__gxx_personality_v0
6102 catch i8** @_ZTIi
6103 ;; A landing pad that is a cleanup.
6104 %res = landingpad { i8*, i32 } personality i32 (...)* @__gxx_personality_v0
Bill Wendlinge6e88262011-08-12 20:24:12 +0000[diff] [blame]6105 cleanup
Bill Wendlingf78faf82011-08-02 21:52:38 +0000[diff] [blame]6106 ;; A landing pad which can catch an integer and can only throw a double.
6107 %res = landingpad { i8*, i32 } personality i32 (...)* @__gxx_personality_v0
6108 catch i8** @_ZTIi
Bill Wendlinge6e88262011-08-12 20:24:12 +0000[diff] [blame]6109 filter [1 x i8**] [@_ZTId]
Bill Wendlingf78faf82011-08-02 21:52:38 +0000[diff] [blame]6110</pre>
6111
6112</div>
6113
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6114</div>
6115
6116</div>
6117
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6118<!-- *********************************************************************** -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6119<h2><a name="intrinsics">Intrinsic Functions</a></h2>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]6120<!-- *********************************************************************** -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6121
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6122<div>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6123
6124<p>LLVM supports the notion of an "intrinsic function". These functions have
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6125 well known names and semantics and are required to follow certain
6126 restrictions. Overall, these intrinsics represent an extension mechanism for
6127 the LLVM language that does not require changing all of the transformations
6128 in LLVM when adding to the language (or the bitcode reader/writer, the
6129 parser, etc...).</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6130
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]6131<p>Intrinsic function names must all start with an "<tt>llvm.</tt>" prefix. This
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6132 prefix is reserved in LLVM for intrinsic names; thus, function names may not
6133 begin with this prefix. Intrinsic functions must always be external
6134 functions: you cannot define the body of intrinsic functions. Intrinsic
6135 functions may only be used in call or invoke instructions: it is illegal to
6136 take the address of an intrinsic function. Additionally, because intrinsic
6137 functions are part of the LLVM language, it is required if any are added that
6138 they be documented here.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6139
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6140<p>Some intrinsic functions can be overloaded, i.e., the intrinsic represents a
6141 family of functions that perform the same operation but on different data
6142 types. Because LLVM can represent over 8 million different integer types,
6143 overloading is used commonly to allow an intrinsic function to operate on any
6144 integer type. One or more of the argument types or the result type can be
6145 overloaded to accept any integer type. Argument types may also be defined as
6146 exactly matching a previous argument's type or the result type. This allows
6147 an intrinsic function which accepts multiple arguments, but needs all of them
6148 to be of the same type, to only be overloaded with respect to a single
6149 argument or the result.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6150
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6151<p>Overloaded intrinsics will have the names of its overloaded argument types
6152 encoded into its function name, each preceded by a period. Only those types
6153 which are overloaded result in a name suffix. Arguments whose type is matched
6154 against another type do not. For example, the <tt>llvm.ctpop</tt> function
6155 can take an integer of any width and returns an integer of exactly the same
6156 integer width. This leads to a family of functions such as
6157 <tt>i8 @llvm.ctpop.i8(i8 %val)</tt> and <tt>i29 @llvm.ctpop.i29(i29
6158 %val)</tt>. Only one type, the return type, is overloaded, and only one type
6159 suffix is required. Because the argument's type is matched against the return
6160 type, it does not require its own name suffix.</p>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]6161
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]6162<p>To learn how to add an intrinsic function, please see the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6163 <a href="ExtendingLLVM.html">Extending LLVM Guide</a>.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6164
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6165<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6166<h3>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6167 <a name="int_varargs">Variable Argument Handling Intrinsics</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6168</h3>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6169
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6170<div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6171
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6172<p>Variable argument support is defined in LLVM with
6173 the <a href="#i_va_arg"><tt>va_arg</tt></a> instruction and these three
6174 intrinsic functions. These functions are related to the similarly named
6175 macros defined in the <tt>&lt;stdarg.h&gt;</tt> header file.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6176
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6177<p>All of these functions operate on arguments that use a target-specific value
6178 type "<tt>va_list</tt>". The LLVM assembly language reference manual does
6179 not define what this type is, so all transformations should be prepared to
6180 handle these functions regardless of the type used.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6181
Chris Lattner374ab302006-05-15 17:26:46 +0000[diff] [blame]6182<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]6183 instruction and the variable argument handling intrinsic functions are
6184 used.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6185
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]6186<pre class="doc_code">
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]6187define i32 @test(i32 %X, ...) {
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6188 ; Initialize variable argument processing
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]6189 %ap = alloca i8*
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]6190 %ap2 = bitcast i8** %ap to i8*
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]6191 call void @llvm.va_start(i8* %ap2)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6192
6193 ; Read a single integer argument
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]6194 %tmp = va_arg i8** %ap, i32
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6195
6196 ; Demonstrate usage of llvm.va_copy and llvm.va_end
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]6197 %aq = alloca i8*
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]6198 %aq2 = bitcast i8** %aq to i8*
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]6199 call void @llvm.va_copy(i8* %aq2, i8* %ap2)
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]6200 call void @llvm.va_end(i8* %aq2)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6201
6202 ; Stop processing of arguments.
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]6203 call void @llvm.va_end(i8* %ap2)
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]6204 ret i32 %tmp
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6205}
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]6206
6207declare void @llvm.va_start(i8*)
6208declare void @llvm.va_copy(i8*, i8*)
6209declare void @llvm.va_end(i8*)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6210</pre>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6211
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6212<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6213<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6214 <a name="int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6215</h4>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6216
6217
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6218<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6219
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6220<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6221<pre>
6222 declare void %llvm.va_start(i8* &lt;arglist&gt;)
6223</pre>
6224
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6225<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6226<p>The '<tt>llvm.va_start</tt>' intrinsic initializes <tt>*&lt;arglist&gt;</tt>
6227 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]6228
6229<h5>Arguments:</h5>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]6230<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]6231
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6232<h5>Semantics:</h5>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]6233<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]6234 macro available in C. In a target-dependent way, it initializes
6235 the <tt>va_list</tt> element to which the argument points, so that the next
6236 call to <tt>va_arg</tt> will produce the first variable argument passed to
6237 the function. Unlike the C <tt>va_start</tt> macro, this intrinsic does not
6238 need to know the last argument of the function as the compiler can figure
6239 that out.</p>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]6240
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]6241</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6242
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6243<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6244<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6245 <a name="int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6246</h4>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6247
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6248<div>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]6249
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6250<h5>Syntax:</h5>
6251<pre>
6252 declare void @llvm.va_end(i8* &lt;arglist&gt;)
6253</pre>
6254
6255<h5>Overview:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]6256<p>The '<tt>llvm.va_end</tt>' intrinsic destroys <tt>*&lt;arglist&gt;</tt>,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6257 which has been initialized previously
6258 with <tt><a href="#int_va_start">llvm.va_start</a></tt>
6259 or <tt><a href="#i_va_copy">llvm.va_copy</a></tt>.</p>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]6260
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6261<h5>Arguments:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]6262<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]6263
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6264<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]6265<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]6266 macro available in C. In a target-dependent way, it destroys
6267 the <tt>va_list</tt> element to which the argument points. Calls
6268 to <a href="#int_va_start"><tt>llvm.va_start</tt></a>
6269 and <a href="#int_va_copy"> <tt>llvm.va_copy</tt></a> must be matched exactly
6270 with calls to <tt>llvm.va_end</tt>.</p>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]6271
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]6272</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6273
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6274<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6275<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6276 <a name="int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6277</h4>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6278
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6279<div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6280
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6281<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6282<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]6283 declare void @llvm.va_copy(i8* &lt;destarglist&gt;, i8* &lt;srcarglist&gt;)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6284</pre>
6285
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6286<h5>Overview:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]6287<p>The '<tt>llvm.va_copy</tt>' intrinsic copies the current argument position
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6288 from the source argument list to the destination argument list.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6289
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6290<h5>Arguments:</h5>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]6291<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]6292 The second argument is a pointer to a <tt>va_list</tt> element to copy
6293 from.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6294
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6295<h5>Semantics:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]6296<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]6297 macro available in C. In a target-dependent way, it copies the
6298 source <tt>va_list</tt> element into the destination <tt>va_list</tt>
6299 element. This intrinsic is necessary because
6300 the <tt><a href="#int_va_start"> llvm.va_start</a></tt> intrinsic may be
6301 arbitrarily complex and require, for example, memory allocation.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6302
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]6303</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6304
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6305</div>
6306
Bill Wendling0246bb72011-07-31 06:45:03 +0000[diff] [blame]6307</div>
6308
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6309<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6310<h3>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6311 <a name="int_gc">Accurate Garbage Collection Intrinsics</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6312</h3>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6313
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6314<div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6315
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6316<p>LLVM support for <a href="GarbageCollection.html">Accurate Garbage
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]6317Collection</a> (GC) requires the implementation and generation of these
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6318intrinsics. These intrinsics allow identification of <a href="#int_gcroot">GC
6319roots on the stack</a>, as well as garbage collector implementations that
6320require <a href="#int_gcread">read</a> and <a href="#int_gcwrite">write</a>
6321barriers. Front-ends for type-safe garbage collected languages should generate
6322these intrinsics to make use of the LLVM garbage collectors. For more details,
6323see <a href="GarbageCollection.html">Accurate Garbage Collection with
6324LLVM</a>.</p>
Christopher Lamb303dae92007-12-17 01:00:21 +0000[diff] [blame]6325
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6326<p>The garbage collection intrinsics only operate on objects in the generic
6327 address space (address space zero).</p>
Christopher Lamb303dae92007-12-17 01:00:21 +0000[diff] [blame]6328
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6329<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6330<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6331 <a name="int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6332</h4>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6333
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6334<div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6335
6336<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6337<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]6338 declare void @llvm.gcroot(i8** %ptrloc, i8* %metadata)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6339</pre>
6340
6341<h5>Overview:</h5>
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]6342<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]6343 the code generator, and allows some metadata to be associated with it.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6344
6345<h5>Arguments:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6346<p>The first argument specifies the address of a stack object that contains the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6347 root pointer. The second pointer (which must be either a constant or a
6348 global value address) contains the meta-data to be associated with the
6349 root.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6350
6351<h5>Semantics:</h5>
Chris Lattner05d67092008-04-24 05:59:56 +0000[diff] [blame]6352<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]6353 location. At compile-time, the code generator generates information to allow
6354 the runtime to find the pointer at GC safe points. The '<tt>llvm.gcroot</tt>'
6355 intrinsic may only be used in a function which <a href="#gc">specifies a GC
6356 algorithm</a>.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6357
6358</div>
6359
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6360<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6361<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6362 <a name="int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6363</h4>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6364
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6365<div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6366
6367<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6368<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]6369 declare i8* @llvm.gcread(i8* %ObjPtr, i8** %Ptr)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6370</pre>
6371
6372<h5>Overview:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6373<p>The '<tt>llvm.gcread</tt>' intrinsic identifies reads of references from heap
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6374 locations, allowing garbage collector implementations that require read
6375 barriers.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6376
6377<h5>Arguments:</h5>
Chris Lattner80626e92006-03-14 20:02:51 +0000[diff] [blame]6378<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]6379 allocated from the garbage collector. The first object is a pointer to the
6380 start of the referenced object, if needed by the language runtime (otherwise
6381 null).</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6382
6383<h5>Semantics:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6384<p>The '<tt>llvm.gcread</tt>' intrinsic has the same semantics as a load
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6385 instruction, but may be replaced with substantially more complex code by the
6386 garbage collector runtime, as needed. The '<tt>llvm.gcread</tt>' intrinsic
6387 may only be used in a function which <a href="#gc">specifies a GC
6388 algorithm</a>.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6389
6390</div>
6391
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6392<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6393<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6394 <a name="int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6395</h4>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6396
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6397<div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6398
6399<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6400<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]6401 declare void @llvm.gcwrite(i8* %P1, i8* %Obj, i8** %P2)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6402</pre>
6403
6404<h5>Overview:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6405<p>The '<tt>llvm.gcwrite</tt>' intrinsic identifies writes of references to heap
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6406 locations, allowing garbage collector implementations that require write
6407 barriers (such as generational or reference counting collectors).</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6408
6409<h5>Arguments:</h5>
Chris Lattner80626e92006-03-14 20:02:51 +0000[diff] [blame]6410<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]6411 object to store it to, and the third is the address of the field of Obj to
6412 store to. If the runtime does not require a pointer to the object, Obj may
6413 be null.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6414
6415<h5>Semantics:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6416<p>The '<tt>llvm.gcwrite</tt>' intrinsic has the same semantics as a store
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6417 instruction, but may be replaced with substantially more complex code by the
6418 garbage collector runtime, as needed. The '<tt>llvm.gcwrite</tt>' intrinsic
6419 may only be used in a function which <a href="#gc">specifies a GC
6420 algorithm</a>.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6421
6422</div>
6423
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6424</div>
6425
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6426<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6427<h3>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6428 <a name="int_codegen">Code Generator Intrinsics</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6429</h3>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6430
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6431<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6432
6433<p>These intrinsics are provided by LLVM to expose special features that may
6434 only be implemented with code generator support.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6435
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6436<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6437<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6438 <a name="int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6439</h4>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6440
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6441<div>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6442
6443<h5>Syntax:</h5>
6444<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]6445 declare i8 *@llvm.returnaddress(i32 &lt;level&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6446</pre>
6447
6448<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6449<p>The '<tt>llvm.returnaddress</tt>' intrinsic attempts to compute a
6450 target-specific value indicating the return address of the current function
6451 or one of its callers.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6452
6453<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6454<p>The argument to this intrinsic indicates which function to return the address
6455 for. Zero indicates the calling function, one indicates its caller, etc.
6456 The argument is <b>required</b> to be a constant integer value.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6457
6458<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6459<p>The '<tt>llvm.returnaddress</tt>' intrinsic either returns a pointer
6460 indicating the return address of the specified call frame, or zero if it
6461 cannot be identified. The value returned by this intrinsic is likely to be
6462 incorrect or 0 for arguments other than zero, so it should only be used for
6463 debugging purposes.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6464
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6465<p>Note that calling this intrinsic does not prevent function inlining or other
6466 aggressive transformations, so the value returned may not be that of the
6467 obvious source-language caller.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6468
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6469</div>
6470
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6471<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6472<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6473 <a name="int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6474</h4>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6475
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6476<div>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6477
6478<h5>Syntax:</h5>
6479<pre>
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]6480 declare i8* @llvm.frameaddress(i32 &lt;level&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6481</pre>
6482
6483<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6484<p>The '<tt>llvm.frameaddress</tt>' intrinsic attempts to return the
6485 target-specific frame pointer value for the specified stack frame.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6486
6487<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6488<p>The argument to this intrinsic indicates which function to return the frame
6489 pointer for. Zero indicates the calling function, one indicates its caller,
6490 etc. The argument is <b>required</b> to be a constant integer value.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6491
6492<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6493<p>The '<tt>llvm.frameaddress</tt>' intrinsic either returns a pointer
6494 indicating the frame address of the specified call frame, or zero if it
6495 cannot be identified. The value returned by this intrinsic is likely to be
6496 incorrect or 0 for arguments other than zero, so it should only be used for
6497 debugging purposes.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6498
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6499<p>Note that calling this intrinsic does not prevent function inlining or other
6500 aggressive transformations, so the value returned may not be that of the
6501 obvious source-language caller.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6502
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6503</div>
6504
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]6505<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6506<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6507 <a name="int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6508</h4>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]6509
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6510<div>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]6511
6512<h5>Syntax:</h5>
6513<pre>
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]6514 declare i8* @llvm.stacksave()
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]6515</pre>
6516
6517<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6518<p>The '<tt>llvm.stacksave</tt>' intrinsic is used to remember the current state
6519 of the function stack, for use
6520 with <a href="#int_stackrestore"> <tt>llvm.stackrestore</tt></a>. This is
6521 useful for implementing language features like scoped automatic variable
6522 sized arrays in C99.</p>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]6523
6524<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6525<p>This intrinsic returns a opaque pointer value that can be passed
6526 to <a href="#int_stackrestore"><tt>llvm.stackrestore</tt></a>. When
6527 an <tt>llvm.stackrestore</tt> intrinsic is executed with a value saved
6528 from <tt>llvm.stacksave</tt>, it effectively restores the state of the stack
6529 to the state it was in when the <tt>llvm.stacksave</tt> intrinsic executed.
6530 In practice, this pops any <a href="#i_alloca">alloca</a> blocks from the
6531 stack that were allocated after the <tt>llvm.stacksave</tt> was executed.</p>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]6532
6533</div>
6534
6535<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6536<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6537 <a name="int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6538</h4>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]6539
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6540<div>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]6541
6542<h5>Syntax:</h5>
6543<pre>
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]6544 declare void @llvm.stackrestore(i8* %ptr)
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]6545</pre>
6546
6547<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6548<p>The '<tt>llvm.stackrestore</tt>' intrinsic is used to restore the state of
6549 the function stack to the state it was in when the
6550 corresponding <a href="#int_stacksave"><tt>llvm.stacksave</tt></a> intrinsic
6551 executed. This is useful for implementing language features like scoped
6552 automatic variable sized arrays in C99.</p>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]6553
6554<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6555<p>See the description
6556 for <a href="#int_stacksave"><tt>llvm.stacksave</tt></a>.</p>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]6557
6558</div>
6559
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]6560<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6561<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6562 <a name="int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6563</h4>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]6564
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6565<div>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]6566
6567<h5>Syntax:</h5>
6568<pre>
Bruno Cardoso Lopes9a767332011-06-14 04:58:37 +0000[diff] [blame]6569 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]6570</pre>
6571
6572<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6573<p>The '<tt>llvm.prefetch</tt>' intrinsic is a hint to the code generator to
6574 insert a prefetch instruction if supported; otherwise, it is a noop.
6575 Prefetches have no effect on the behavior of the program but can change its
6576 performance characteristics.</p>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]6577
6578<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6579<p><tt>address</tt> is the address to be prefetched, <tt>rw</tt> is the
6580 specifier determining if the fetch should be for a read (0) or write (1),
6581 and <tt>locality</tt> is a temporal locality specifier ranging from (0) - no
Bruno Cardoso Lopes9a767332011-06-14 04:58:37 +0000[diff] [blame]6582 locality, to (3) - extremely local keep in cache. The <tt>cache type</tt>
6583 specifies whether the prefetch is performed on the data (1) or instruction (0)
6584 cache. The <tt>rw</tt>, <tt>locality</tt> and <tt>cache type</tt> arguments
6585 must be constant integers.</p>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]6586
6587<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6588<p>This intrinsic does not modify the behavior of the program. In particular,
6589 prefetches cannot trap and do not produce a value. On targets that support
6590 this intrinsic, the prefetch can provide hints to the processor cache for
6591 better performance.</p>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]6592
6593</div>
6594
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]6595<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6596<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6597 <a name="int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6598</h4>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]6599
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6600<div>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]6601
6602<h5>Syntax:</h5>
6603<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]6604 declare void @llvm.pcmarker(i32 &lt;id&gt;)
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]6605</pre>
6606
6607<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6608<p>The '<tt>llvm.pcmarker</tt>' intrinsic is a method to export a Program
6609 Counter (PC) in a region of code to simulators and other tools. The method
6610 is target specific, but it is expected that the marker will use exported
6611 symbols to transmit the PC of the marker. The marker makes no guarantees
6612 that it will remain with any specific instruction after optimizations. It is
6613 possible that the presence of a marker will inhibit optimizations. The
6614 intended use is to be inserted after optimizations to allow correlations of
6615 simulation runs.</p>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]6616
6617<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6618<p><tt>id</tt> is a numerical id identifying the marker.</p>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]6619
6620<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6621<p>This intrinsic does not modify the behavior of the program. Backends that do
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]6622 not support this intrinsic may ignore it.</p>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]6623
6624</div>
6625
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]6626<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6627<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6628 <a name="int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6629</h4>
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]6630
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6631<div>
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]6632
6633<h5>Syntax:</h5>
6634<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]6635 declare i64 @llvm.readcyclecounter()
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]6636</pre>
6637
6638<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6639<p>The '<tt>llvm.readcyclecounter</tt>' intrinsic provides access to the cycle
6640 counter register (or similar low latency, high accuracy clocks) on those
6641 targets that support it. On X86, it should map to RDTSC. On Alpha, it
6642 should map to RPCC. As the backing counters overflow quickly (on the order
6643 of 9 seconds on alpha), this should only be used for small timings.</p>
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]6644
6645<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6646<p>When directly supported, reading the cycle counter should not modify any
6647 memory. Implementations are allowed to either return a application specific
6648 value or a system wide value. On backends without support, this is lowered
6649 to a constant 0.</p>
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]6650
6651</div>
6652
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6653</div>
6654
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6655<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6656<h3>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6657 <a name="int_libc">Standard C Library Intrinsics</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6658</h3>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6659
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6660<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6661
6662<p>LLVM provides intrinsics for a few important standard C library functions.
6663 These intrinsics allow source-language front-ends to pass information about
6664 the alignment of the pointer arguments to the code generator, providing
6665 opportunity for more efficient code generation.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6666
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6667<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6668<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6669 <a name="int_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6670</h4>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6671
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6672<div>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6673
6674<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6675<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]6676 integer bit width and for different address spaces. Not all targets support
6677 all bit widths however.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6678
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6679<pre>
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]6680 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]6681 i32 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]6682 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]6683 i64 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6684</pre>
6685
6686<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6687<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
6688 source location to the destination location.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6689
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6690<p>Note that, unlike the standard libc function, the <tt>llvm.memcpy.*</tt>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6691 intrinsics do not return a value, takes extra alignment/isvolatile arguments
6692 and the pointers can be in specified address spaces.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6693
6694<h5>Arguments:</h5>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6695
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6696<p>The first argument is a pointer to the destination, the second is a pointer
6697 to the source. The third argument is an integer argument specifying the
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6698 number of bytes to copy, the fourth argument is the alignment of the
6699 source and destination locations, and the fifth is a boolean indicating a
6700 volatile access.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6701
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]6702<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]6703 then the caller guarantees that both the source and destination pointers are
6704 aligned to that boundary.</p>
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]6705
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]6706<p>If the <tt>isvolatile</tt> parameter is <tt>true</tt>, the
6707 <tt>llvm.memcpy</tt> call is a <a href="#volatile">volatile operation</a>.
6708 The detailed access behavior is not very cleanly specified and it is unwise
6709 to depend on it.</p>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6710
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6711<h5>Semantics:</h5>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6712
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6713<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
6714 source location to the destination location, which are not allowed to
6715 overlap. It copies "len" bytes of memory over. If the argument is known to
6716 be aligned to some boundary, this can be specified as the fourth argument,
6717 otherwise it should be set to 0 or 1.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6718
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6719</div>
6720
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6721<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6722<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6723 <a name="int_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6724</h4>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6725
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6726<div>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6727
6728<h5>Syntax:</h5>
Chris Lattner824b9582008-11-21 16:42:48 +0000[diff] [blame]6729<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]6730 width and for different address space. Not all targets support all bit
6731 widths however.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6732
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6733<pre>
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]6734 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]6735 i32 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]6736 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]6737 i64 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6738</pre>
6739
6740<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6741<p>The '<tt>llvm.memmove.*</tt>' intrinsics move a block of memory from the
6742 source location to the destination location. It is similar to the
6743 '<tt>llvm.memcpy</tt>' intrinsic but allows the two memory locations to
6744 overlap.</p>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6745
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6746<p>Note that, unlike the standard libc function, the <tt>llvm.memmove.*</tt>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6747 intrinsics do not return a value, takes extra alignment/isvolatile arguments
6748 and the pointers can be in specified address spaces.</p>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6749
6750<h5>Arguments:</h5>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6751
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6752<p>The first argument is a pointer to the destination, the second is a pointer
6753 to the source. The third argument is an integer argument specifying the
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6754 number of bytes to copy, the fourth argument is the alignment of the
6755 source and destination locations, and the fifth is a boolean indicating a
6756 volatile access.</p>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6757
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]6758<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]6759 then the caller guarantees that the source and destination pointers are
6760 aligned to that boundary.</p>
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]6761
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]6762<p>If the <tt>isvolatile</tt> parameter is <tt>true</tt>, the
6763 <tt>llvm.memmove</tt> call is a <a href="#volatile">volatile operation</a>.
6764 The detailed access behavior is not very cleanly specified and it is unwise
6765 to depend on it.</p>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6766
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6767<h5>Semantics:</h5>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6768
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6769<p>The '<tt>llvm.memmove.*</tt>' intrinsics copy a block of memory from the
6770 source location to the destination location, which may overlap. It copies
6771 "len" bytes of memory over. If the argument is known to be aligned to some
6772 boundary, this can be specified as the fourth argument, otherwise it should
6773 be set to 0 or 1.</p>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6774
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6775</div>
6776
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6777<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6778<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6779 <a name="int_memset">'<tt>llvm.memset.*</tt>' Intrinsics</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6780</h4>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6781
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6782<div>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6783
6784<h5>Syntax:</h5>
Chris Lattner824b9582008-11-21 16:42:48 +0000[diff] [blame]6785<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]6786 width and for different address spaces. However, not all targets support all
6787 bit widths.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6788
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6789<pre>
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]6790 declare void @llvm.memset.p0i8.i32(i8* &lt;dest&gt;, i8 &lt;val&gt;,
Chris Lattnerff35c3f2010-04-08 00:54:34 +0000[diff] [blame]6791 i32 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]6792 declare void @llvm.memset.p0i8.i64(i8* &lt;dest&gt;, i8 &lt;val&gt;,
Chris Lattnerff35c3f2010-04-08 00:54:34 +0000[diff] [blame]6793 i64 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6794</pre>
6795
6796<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6797<p>The '<tt>llvm.memset.*</tt>' intrinsics fill a block of memory with a
6798 particular byte value.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6799
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6800<p>Note that, unlike the standard libc function, the <tt>llvm.memset</tt>
John Criswellcdcbbfc2010-07-30 16:30:28 +0000[diff] [blame]6801 intrinsic does not return a value and takes extra alignment/volatile
6802 arguments. Also, the destination can be in an arbitrary address space.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6803
6804<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6805<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]6806 byte value with which to fill it, the third argument is an integer argument
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6807 specifying the number of bytes to fill, and the fourth argument is the known
John Criswellcdcbbfc2010-07-30 16:30:28 +0000[diff] [blame]6808 alignment of the destination location.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6809
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]6810<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]6811 then the caller guarantees that the destination pointer is aligned to that
6812 boundary.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6813
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]6814<p>If the <tt>isvolatile</tt> parameter is <tt>true</tt>, the
6815 <tt>llvm.memset</tt> call is a <a href="#volatile">volatile operation</a>.
6816 The detailed access behavior is not very cleanly specified and it is unwise
6817 to depend on it.</p>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6818
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6819<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6820<p>The '<tt>llvm.memset.*</tt>' intrinsics fill "len" bytes of memory starting
6821 at the destination location. If the argument is known to be aligned to some
6822 boundary, this can be specified as the fourth argument, otherwise it should
6823 be set to 0 or 1.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6824
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6825</div>
6826
Chris Lattner32006282004-06-11 02:28:03 +0000[diff] [blame]6827<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6828<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6829 <a name="int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6830</h4>
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]6831
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6832<div>
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]6833
6834<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6835<p>This is an overloaded intrinsic. You can use <tt>llvm.sqrt</tt> on any
6836 floating point or vector of floating point type. Not all targets support all
6837 types however.</p>
6838
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]6839<pre>
Dale Johannesen408f9c12007-10-02 17:47:38 +0000[diff] [blame]6840 declare float @llvm.sqrt.f32(float %Val)
6841 declare double @llvm.sqrt.f64(double %Val)
6842 declare x86_fp80 @llvm.sqrt.f80(x86_fp80 %Val)
6843 declare fp128 @llvm.sqrt.f128(fp128 %Val)
6844 declare ppc_fp128 @llvm.sqrt.ppcf128(ppc_fp128 %Val)
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]6845</pre>
6846
6847<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6848<p>The '<tt>llvm.sqrt</tt>' intrinsics return the sqrt of the specified operand,
6849 returning the same value as the libm '<tt>sqrt</tt>' functions would.
6850 Unlike <tt>sqrt</tt> in libm, however, <tt>llvm.sqrt</tt> has undefined
6851 behavior for negative numbers other than -0.0 (which allows for better
6852 optimization, because there is no need to worry about errno being
6853 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]6854
6855<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6856<p>The argument and return value are floating point numbers of the same
6857 type.</p>
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]6858
6859<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6860<p>This function returns the sqrt of the specified operand if it is a
6861 nonnegative floating point number.</p>
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]6862
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]6863</div>
6864
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6865<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6866<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6867 <a name="int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6868</h4>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6869
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6870<div>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6871
6872<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6873<p>This is an overloaded intrinsic. You can use <tt>llvm.powi</tt> on any
6874 floating point or vector of floating point type. Not all targets support all
6875 types however.</p>
6876
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6877<pre>
Dale Johannesen408f9c12007-10-02 17:47:38 +0000[diff] [blame]6878 declare float @llvm.powi.f32(float %Val, i32 %power)
6879 declare double @llvm.powi.f64(double %Val, i32 %power)
6880 declare x86_fp80 @llvm.powi.f80(x86_fp80 %Val, i32 %power)
6881 declare fp128 @llvm.powi.f128(fp128 %Val, i32 %power)
6882 declare ppc_fp128 @llvm.powi.ppcf128(ppc_fp128 %Val, i32 %power)
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6883</pre>
6884
6885<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6886<p>The '<tt>llvm.powi.*</tt>' intrinsics return the first operand raised to the
6887 specified (positive or negative) power. The order of evaluation of
6888 multiplications is not defined. When a vector of floating point type is
6889 used, the second argument remains a scalar integer value.</p>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6890
6891<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6892<p>The second argument is an integer power, and the first is a value to raise to
6893 that power.</p>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6894
6895<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6896<p>This function returns the first value raised to the second power with an
6897 unspecified sequence of rounding operations.</p>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6898
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6899</div>
6900
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6901<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6902<h4>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6903 <a name="int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6904</h4>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6905
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6906<div>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6907
6908<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6909<p>This is an overloaded intrinsic. You can use <tt>llvm.sin</tt> on any
6910 floating point or vector of floating point type. Not all targets support all
6911 types however.</p>
6912
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6913<pre>
6914 declare float @llvm.sin.f32(float %Val)
6915 declare double @llvm.sin.f64(double %Val)
6916 declare x86_fp80 @llvm.sin.f80(x86_fp80 %Val)
6917 declare fp128 @llvm.sin.f128(fp128 %Val)
6918 declare ppc_fp128 @llvm.sin.ppcf128(ppc_fp128 %Val)
6919</pre>
6920
6921<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6922<p>The '<tt>llvm.sin.*</tt>' intrinsics return the sine of the operand.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6923
6924<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6925<p>The argument and return value are floating point numbers of the same
6926 type.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6927
6928<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6929<p>This function returns the sine of the specified operand, returning the same
6930 values as the libm <tt>sin</tt> functions would, and handles error conditions
6931 in the same way.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6932
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6933</div>
6934
6935<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6936<h4>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6937 <a name="int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6938</h4>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6939
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6940<div>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6941
6942<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6943<p>This is an overloaded intrinsic. You can use <tt>llvm.cos</tt> on any
6944 floating point or vector of floating point type. Not all targets support all
6945 types however.</p>
6946
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6947<pre>
6948 declare float @llvm.cos.f32(float %Val)
6949 declare double @llvm.cos.f64(double %Val)
6950 declare x86_fp80 @llvm.cos.f80(x86_fp80 %Val)
6951 declare fp128 @llvm.cos.f128(fp128 %Val)
6952 declare ppc_fp128 @llvm.cos.ppcf128(ppc_fp128 %Val)
6953</pre>
6954
6955<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6956<p>The '<tt>llvm.cos.*</tt>' intrinsics return the cosine of the operand.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6957
6958<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6959<p>The argument and return value are floating point numbers of the same
6960 type.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6961
6962<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6963<p>This function returns the cosine of the specified operand, returning the same
6964 values as the libm <tt>cos</tt> functions would, and handles error conditions
6965 in the same way.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6966
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6967</div>
6968
6969<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6970<h4>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6971 <a name="int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6972</h4>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6973
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6974<div>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6975
6976<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6977<p>This is an overloaded intrinsic. You can use <tt>llvm.pow</tt> on any
6978 floating point or vector of floating point type. Not all targets support all
6979 types however.</p>
6980
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6981<pre>
6982 declare float @llvm.pow.f32(float %Val, float %Power)
6983 declare double @llvm.pow.f64(double %Val, double %Power)
6984 declare x86_fp80 @llvm.pow.f80(x86_fp80 %Val, x86_fp80 %Power)
6985 declare fp128 @llvm.pow.f128(fp128 %Val, fp128 %Power)
6986 declare ppc_fp128 @llvm.pow.ppcf128(ppc_fp128 %Val, ppc_fp128 Power)
6987</pre>
6988
6989<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6990<p>The '<tt>llvm.pow.*</tt>' intrinsics return the first operand raised to the
6991 specified (positive or negative) power.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6992
6993<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6994<p>The second argument is a floating point power, and the first is a value to
6995 raise to that power.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6996
6997<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6998<p>This function returns the first value raised to the second power, returning
6999 the same values as the libm <tt>pow</tt> functions would, and handles error
7000 conditions in the same way.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7001
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7002</div>
7003
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7004</div>
7005
Dan Gohman4e9011c2011-05-23 21:13:03 +0000[diff] [blame]7006<!-- _______________________________________________________________________ -->
7007<h4>
7008 <a name="int_exp">'<tt>llvm.exp.*</tt>' Intrinsic</a>
7009</h4>
7010
7011<div>
7012
7013<h5>Syntax:</h5>
7014<p>This is an overloaded intrinsic. You can use <tt>llvm.exp</tt> on any
7015 floating point or vector of floating point type. Not all targets support all
7016 types however.</p>
7017
7018<pre>
7019 declare float @llvm.exp.f32(float %Val)
7020 declare double @llvm.exp.f64(double %Val)
7021 declare x86_fp80 @llvm.exp.f80(x86_fp80 %Val)
7022 declare fp128 @llvm.exp.f128(fp128 %Val)
7023 declare ppc_fp128 @llvm.exp.ppcf128(ppc_fp128 %Val)
7024</pre>
7025
7026<h5>Overview:</h5>
7027<p>The '<tt>llvm.exp.*</tt>' intrinsics perform the exp function.</p>
7028
7029<h5>Arguments:</h5>
7030<p>The argument and return value are floating point numbers of the same
7031 type.</p>
7032
7033<h5>Semantics:</h5>
7034<p>This function returns the same values as the libm <tt>exp</tt> functions
7035 would, and handles error conditions in the same way.</p>
7036
7037</div>
7038
7039<!-- _______________________________________________________________________ -->
7040<h4>
7041 <a name="int_log">'<tt>llvm.log.*</tt>' Intrinsic</a>
7042</h4>
7043
7044<div>
7045
7046<h5>Syntax:</h5>
7047<p>This is an overloaded intrinsic. You can use <tt>llvm.log</tt> on any
7048 floating point or vector of floating point type. Not all targets support all
7049 types however.</p>
7050
7051<pre>
7052 declare float @llvm.log.f32(float %Val)
7053 declare double @llvm.log.f64(double %Val)
7054 declare x86_fp80 @llvm.log.f80(x86_fp80 %Val)
7055 declare fp128 @llvm.log.f128(fp128 %Val)
7056 declare ppc_fp128 @llvm.log.ppcf128(ppc_fp128 %Val)
7057</pre>
7058
7059<h5>Overview:</h5>
7060<p>The '<tt>llvm.log.*</tt>' intrinsics perform the log function.</p>
7061
7062<h5>Arguments:</h5>
7063<p>The argument and return value are floating point numbers of the same
7064 type.</p>
7065
7066<h5>Semantics:</h5>
7067<p>This function returns the same values as the libm <tt>log</tt> functions
7068 would, and handles error conditions in the same way.</p>
7069
Cameron Zwarich33390842011-07-08 21:39:21 +0000[diff] [blame]7070<h4>
7071 <a name="int_fma">'<tt>llvm.fma.*</tt>' Intrinsic</a>
7072</h4>
7073
7074<div>
7075
7076<h5>Syntax:</h5>
7077<p>This is an overloaded intrinsic. You can use <tt>llvm.fma</tt> on any
7078 floating point or vector of floating point type. Not all targets support all
7079 types however.</p>
7080
7081<pre>
7082 declare float @llvm.fma.f32(float %a, float %b, float %c)
7083 declare double @llvm.fma.f64(double %a, double %b, double %c)
7084 declare x86_fp80 @llvm.fma.f80(x86_fp80 %a, x86_fp80 %b, x86_fp80 %c)
7085 declare fp128 @llvm.fma.f128(fp128 %a, fp128 %b, fp128 %c)
7086 declare ppc_fp128 @llvm.fma.ppcf128(ppc_fp128 %a, ppc_fp128 %b, ppc_fp128 %c)
7087</pre>
7088
7089<h5>Overview:</h5>
Cameron Zwarichabc43e62011-07-08 22:13:55 +0000[diff] [blame]7090<p>The '<tt>llvm.fma.*</tt>' intrinsics perform the fused multiply-add
Cameron Zwarich33390842011-07-08 21:39:21 +0000[diff] [blame]7091 operation.</p>
7092
7093<h5>Arguments:</h5>
7094<p>The argument and return value are floating point numbers of the same
7095 type.</p>
7096
7097<h5>Semantics:</h5>
7098<p>This function returns the same values as the libm <tt>fma</tt> functions
7099 would.</p>
7100
Dan Gohman4e9011c2011-05-23 21:13:03 +0000[diff] [blame]7101</div>
7102
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7103<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7104<h3>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]7105 <a name="int_manip">Bit Manipulation Intrinsics</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7106</h3>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7107
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7108<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7109
7110<p>LLVM provides intrinsics for a few important bit manipulation operations.
7111 These allow efficient code generation for some algorithms.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7112
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7113<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7114<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]7115 <a name="int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7116</h4>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]7117
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7118<div>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]7119
7120<h5>Syntax:</h5>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]7121<p>This is an overloaded intrinsic function. You can use bswap on any integer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7122 type that is an even number of bytes (i.e. BitWidth % 16 == 0).</p>
7123
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]7124<pre>
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]7125 declare i16 @llvm.bswap.i16(i16 &lt;id&gt;)
7126 declare i32 @llvm.bswap.i32(i32 &lt;id&gt;)
7127 declare i64 @llvm.bswap.i64(i64 &lt;id&gt;)
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]7128</pre>
7129
7130<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7131<p>The '<tt>llvm.bswap</tt>' family of intrinsics is used to byte swap integer
7132 values with an even number of bytes (positive multiple of 16 bits). These
7133 are useful for performing operations on data that is not in the target's
7134 native byte order.</p>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]7135
7136<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7137<p>The <tt>llvm.bswap.i16</tt> intrinsic returns an i16 value that has the high
7138 and low byte of the input i16 swapped. Similarly,
7139 the <tt>llvm.bswap.i32</tt> intrinsic returns an i32 value that has the four
7140 bytes of the input i32 swapped, so that if the input bytes are numbered 0, 1,
7141 2, 3 then the returned i32 will have its bytes in 3, 2, 1, 0 order.
7142 The <tt>llvm.bswap.i48</tt>, <tt>llvm.bswap.i64</tt> and other intrinsics
7143 extend this concept to additional even-byte lengths (6 bytes, 8 bytes and
7144 more, respectively).</p>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]7145
7146</div>
7147
7148<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7149<h4>
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]7150 <a name="int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7151</h4>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7152
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7153<div>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7154
7155<h5>Syntax:</h5>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]7156<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]7157 width, or on any vector with integer elements. Not all targets support all
7158 bit widths or vector types, however.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7159
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7160<pre>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7161 declare i8 @llvm.ctpop.i8(i8 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]7162 declare i16 @llvm.ctpop.i16(i16 &lt;src&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]7163 declare i32 @llvm.ctpop.i32(i32 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]7164 declare i64 @llvm.ctpop.i64(i64 &lt;src&gt;)
7165 declare i256 @llvm.ctpop.i256(i256 &lt;src&gt;)
Owen Andersonf1ac4652011-07-01 21:52:38 +0000[diff] [blame]7166 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]7167</pre>
7168
7169<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7170<p>The '<tt>llvm.ctpop</tt>' family of intrinsics counts the number of bits set
7171 in a value.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7172
7173<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7174<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]7175 integer type, or a vector with integer elements.
7176 The return type must match the argument type.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7177
7178<h5>Semantics:</h5>
Owen Andersonf1ac4652011-07-01 21:52:38 +0000[diff] [blame]7179<p>The '<tt>llvm.ctpop</tt>' intrinsic counts the 1's in a variable, or within each
7180 element of a vector.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7181
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7182</div>
7183
7184<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7185<h4>
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]7186 <a name="int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7187</h4>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7188
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7189<div>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7190
7191<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7192<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]7193 integer bit width, or any vector whose elements are integers. Not all
7194 targets support all bit widths or vector types, however.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7195
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7196<pre>
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]7197 declare i8 @llvm.ctlz.i8 (i8 &lt;src&gt;)
7198 declare i16 @llvm.ctlz.i16(i16 &lt;src&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]7199 declare i32 @llvm.ctlz.i32(i32 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]7200 declare i64 @llvm.ctlz.i64(i64 &lt;src&gt;)
7201 declare i256 @llvm.ctlz.i256(i256 &lt;src&gt;)
Owen Andersonf1ac4652011-07-01 21:52:38 +0000[diff] [blame]7202 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]7203</pre>
7204
7205<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7206<p>The '<tt>llvm.ctlz</tt>' family of intrinsic functions counts the number of
7207 leading zeros in a variable.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7208
7209<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7210<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]7211 integer type, or any vector type with integer element type.
7212 The return type must match the argument type.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7213
7214<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7215<p>The '<tt>llvm.ctlz</tt>' intrinsic counts the leading (most significant)
Owen Andersonf1ac4652011-07-01 21:52:38 +0000[diff] [blame]7216 zeros in a variable, or within each element of the vector if the operation
7217 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]7218 the type of src. For example, <tt>llvm.ctlz(i32 2) = 30</tt>.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7219
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7220</div>
Chris Lattner32006282004-06-11 02:28:03 +0000[diff] [blame]7221
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]7222<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7223<h4>
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]7224 <a name="int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7225</h4>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]7226
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7227<div>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]7228
7229<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7230<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]7231 integer bit width, or any vector of integer elements. Not all targets
7232 support all bit widths or vector types, however.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7233
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]7234<pre>
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]7235 declare i8 @llvm.cttz.i8 (i8 &lt;src&gt;)
7236 declare i16 @llvm.cttz.i16(i16 &lt;src&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]7237 declare i32 @llvm.cttz.i32(i32 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]7238 declare i64 @llvm.cttz.i64(i64 &lt;src&gt;)
7239 declare i256 @llvm.cttz.i256(i256 &lt;src&gt;)
Owen Andersonf1ac4652011-07-01 21:52:38 +0000[diff] [blame]7240 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]7241</pre>
7242
7243<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7244<p>The '<tt>llvm.cttz</tt>' family of intrinsic functions counts the number of
7245 trailing zeros.</p>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]7246
7247<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7248<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]7249 integer type, or a vectory with integer element type.. The return type
7250 must match the argument type.</p>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]7251
7252<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7253<p>The '<tt>llvm.cttz</tt>' intrinsic counts the trailing (least significant)
Owen Andersonf1ac4652011-07-01 21:52:38 +0000[diff] [blame]7254 zeros in a variable, or within each element of a vector.
7255 If the src == 0 then the result is the size in bits of
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7256 the type of src. For example, <tt>llvm.cttz(2) = 1</tt>.</p>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]7257
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]7258</div>
7259
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7260</div>
7261
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]7262<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7263<h3>
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]7264 <a name="int_overflow">Arithmetic with Overflow Intrinsics</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7265</h3>
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]7266
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7267<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7268
7269<p>LLVM provides intrinsics for some arithmetic with overflow operations.</p>
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]7270
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7271<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7272<h4>
7273 <a name="int_sadd_overflow">
7274 '<tt>llvm.sadd.with.overflow.*</tt>' Intrinsics
7275 </a>
7276</h4>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7277
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7278<div>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7279
7280<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7281<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]7282 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7283
7284<pre>
7285 declare {i16, i1} @llvm.sadd.with.overflow.i16(i16 %a, i16 %b)
7286 declare {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
7287 declare {i64, i1} @llvm.sadd.with.overflow.i64(i64 %a, i64 %b)
7288</pre>
7289
7290<h5>Overview:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7291<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7292 a signed addition of the two arguments, and indicate whether an overflow
7293 occurred during the signed summation.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7294
7295<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7296<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]7297 be of integer types of any bit width, but they must have the same bit
7298 width. The second element of the result structure must be of
7299 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
7300 undergo signed addition.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7301
7302<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7303<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7304 a signed addition of the two variables. They return a structure &mdash; the
7305 first element of which is the signed summation, and the second element of
7306 which is a bit specifying if the signed summation resulted in an
7307 overflow.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7308
7309<h5>Examples:</h5>
7310<pre>
7311 %res = call {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
7312 %sum = extractvalue {i32, i1} %res, 0
7313 %obit = extractvalue {i32, i1} %res, 1
7314 br i1 %obit, label %overflow, label %normal
7315</pre>
7316
7317</div>
7318
7319<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7320<h4>
7321 <a name="int_uadd_overflow">
7322 '<tt>llvm.uadd.with.overflow.*</tt>' Intrinsics
7323 </a>
7324</h4>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7325
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7326<div>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7327
7328<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7329<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]7330 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7331
7332<pre>
7333 declare {i16, i1} @llvm.uadd.with.overflow.i16(i16 %a, i16 %b)
7334 declare {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
7335 declare {i64, i1} @llvm.uadd.with.overflow.i64(i64 %a, i64 %b)
7336</pre>
7337
7338<h5>Overview:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7339<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7340 an unsigned addition of the two arguments, and indicate whether a carry
7341 occurred during the unsigned summation.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7342
7343<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7344<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]7345 be of integer types of any bit width, but they must have the same bit
7346 width. The second element of the result structure must be of
7347 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
7348 undergo unsigned addition.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7349
7350<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7351<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7352 an unsigned addition of the two arguments. They return a structure &mdash;
7353 the first element of which is the sum, and the second element of which is a
7354 bit specifying if the unsigned summation resulted in a carry.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7355
7356<h5>Examples:</h5>
7357<pre>
7358 %res = call {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
7359 %sum = extractvalue {i32, i1} %res, 0
7360 %obit = extractvalue {i32, i1} %res, 1
7361 br i1 %obit, label %carry, label %normal
7362</pre>
7363
7364</div>
7365
7366<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7367<h4>
7368 <a name="int_ssub_overflow">
7369 '<tt>llvm.ssub.with.overflow.*</tt>' Intrinsics
7370 </a>
7371</h4>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7372
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7373<div>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7374
7375<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7376<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]7377 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7378
7379<pre>
7380 declare {i16, i1} @llvm.ssub.with.overflow.i16(i16 %a, i16 %b)
7381 declare {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
7382 declare {i64, i1} @llvm.ssub.with.overflow.i64(i64 %a, i64 %b)
7383</pre>
7384
7385<h5>Overview:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7386<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7387 a signed subtraction of the two arguments, and indicate whether an overflow
7388 occurred during the signed subtraction.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7389
7390<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7391<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]7392 be of integer types of any bit width, but they must have the same bit
7393 width. The second element of the result structure must be of
7394 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
7395 undergo signed subtraction.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7396
7397<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7398<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7399 a signed subtraction of the two arguments. They return a structure &mdash;
7400 the first element of which is the subtraction, and the second element of
7401 which is a bit specifying if the signed subtraction resulted in an
7402 overflow.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7403
7404<h5>Examples:</h5>
7405<pre>
7406 %res = call {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
7407 %sum = extractvalue {i32, i1} %res, 0
7408 %obit = extractvalue {i32, i1} %res, 1
7409 br i1 %obit, label %overflow, label %normal
7410</pre>
7411
7412</div>
7413
7414<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7415<h4>
7416 <a name="int_usub_overflow">
7417 '<tt>llvm.usub.with.overflow.*</tt>' Intrinsics
7418 </a>
7419</h4>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7420
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7421<div>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7422
7423<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7424<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]7425 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7426
7427<pre>
7428 declare {i16, i1} @llvm.usub.with.overflow.i16(i16 %a, i16 %b)
7429 declare {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
7430 declare {i64, i1} @llvm.usub.with.overflow.i64(i64 %a, i64 %b)
7431</pre>
7432
7433<h5>Overview:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7434<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7435 an unsigned subtraction of the two arguments, and indicate whether an
7436 overflow occurred during the unsigned subtraction.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7437
7438<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7439<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]7440 be of integer types of any bit width, but they must have the same bit
7441 width. The second element of the result structure must be of
7442 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
7443 undergo unsigned subtraction.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7444
7445<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7446<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7447 an unsigned subtraction of the two arguments. They return a structure &mdash;
7448 the first element of which is the subtraction, and the second element of
7449 which is a bit specifying if the unsigned subtraction resulted in an
7450 overflow.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7451
7452<h5>Examples:</h5>
7453<pre>
7454 %res = call {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
7455 %sum = extractvalue {i32, i1} %res, 0
7456 %obit = extractvalue {i32, i1} %res, 1
7457 br i1 %obit, label %overflow, label %normal
7458</pre>
7459
7460</div>
7461
7462<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7463<h4>
7464 <a name="int_smul_overflow">
7465 '<tt>llvm.smul.with.overflow.*</tt>' Intrinsics
7466 </a>
7467</h4>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7468
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7469<div>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7470
7471<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7472<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]7473 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7474
7475<pre>
7476 declare {i16, i1} @llvm.smul.with.overflow.i16(i16 %a, i16 %b)
7477 declare {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
7478 declare {i64, i1} @llvm.smul.with.overflow.i64(i64 %a, i64 %b)
7479</pre>
7480
7481<h5>Overview:</h5>
7482
7483<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7484 a signed multiplication of the two arguments, and indicate whether an
7485 overflow occurred during the signed multiplication.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7486
7487<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7488<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]7489 be of integer types of any bit width, but they must have the same bit
7490 width. The second element of the result structure must be of
7491 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
7492 undergo signed multiplication.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7493
7494<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7495<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7496 a signed multiplication of the two arguments. They return a structure &mdash;
7497 the first element of which is the multiplication, and the second element of
7498 which is a bit specifying if the signed multiplication resulted in an
7499 overflow.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7500
7501<h5>Examples:</h5>
7502<pre>
7503 %res = call {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
7504 %sum = extractvalue {i32, i1} %res, 0
7505 %obit = extractvalue {i32, i1} %res, 1
7506 br i1 %obit, label %overflow, label %normal
7507</pre>
7508
Reid Spencerf86037f2007-04-11 23:23:49 +0000[diff] [blame]7509</div>
7510
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]7511<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7512<h4>
7513 <a name="int_umul_overflow">
7514 '<tt>llvm.umul.with.overflow.*</tt>' Intrinsics
7515 </a>
7516</h4>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]7517
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7518<div>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]7519
7520<h5>Syntax:</h5>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]7521<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]7522 on any integer bit width.</p>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]7523
7524<pre>
7525 declare {i16, i1} @llvm.umul.with.overflow.i16(i16 %a, i16 %b)
7526 declare {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
7527 declare {i64, i1} @llvm.umul.with.overflow.i64(i64 %a, i64 %b)
7528</pre>
7529
7530<h5>Overview:</h5>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]7531<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7532 a unsigned multiplication of the two arguments, and indicate whether an
7533 overflow occurred during the unsigned multiplication.</p>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]7534
7535<h5>Arguments:</h5>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]7536<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]7537 be of integer types of any bit width, but they must have the same bit
7538 width. The second element of the result structure must be of
7539 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
7540 undergo unsigned multiplication.</p>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]7541
7542<h5>Semantics:</h5>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]7543<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7544 an unsigned multiplication of the two arguments. They return a structure
7545 &mdash; the first element of which is the multiplication, and the second
7546 element of which is a bit specifying if the unsigned multiplication resulted
7547 in an overflow.</p>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]7548
7549<h5>Examples:</h5>
7550<pre>
7551 %res = call {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
7552 %sum = extractvalue {i32, i1} %res, 0
7553 %obit = extractvalue {i32, i1} %res, 1
7554 br i1 %obit, label %overflow, label %normal
7555</pre>
7556
7557</div>
7558
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7559</div>
7560
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]7561<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7562<h3>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]7563 <a name="int_fp16">Half Precision Floating Point Intrinsics</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7564</h3>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]7565
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7566<div>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]7567
Chris Lattner0cec9c82010-03-15 04:12:21 +0000[diff] [blame]7568<p>Half precision floating point is a storage-only format. This means that it is
7569 a dense encoding (in memory) but does not support computation in the
7570 format.</p>
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]7571
Chris Lattner0cec9c82010-03-15 04:12:21 +0000[diff] [blame]7572<p>This means that code must first load the half-precision floating point
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]7573 value as an i16, then convert it to float with <a
7574 href="#int_convert_from_fp16"><tt>llvm.convert.from.fp16</tt></a>.
7575 Computation can then be performed on the float value (including extending to
Chris Lattner0cec9c82010-03-15 04:12:21 +0000[diff] [blame]7576 double etc). To store the value back to memory, it is first converted to
7577 float if needed, then converted to i16 with
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]7578 <a href="#int_convert_to_fp16"><tt>llvm.convert.to.fp16</tt></a>, then
7579 storing as an i16 value.</p>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]7580
7581<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7582<h4>
7583 <a name="int_convert_to_fp16">
7584 '<tt>llvm.convert.to.fp16</tt>' Intrinsic
7585 </a>
7586</h4>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]7587
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7588<div>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]7589
7590<h5>Syntax:</h5>
7591<pre>
7592 declare i16 @llvm.convert.to.fp16(f32 %a)
7593</pre>
7594
7595<h5>Overview:</h5>
7596<p>The '<tt>llvm.convert.to.fp16</tt>' intrinsic function performs
7597 a conversion from single precision floating point format to half precision
7598 floating point format.</p>
7599
7600<h5>Arguments:</h5>
7601<p>The intrinsic function contains single argument - the value to be
7602 converted.</p>
7603
7604<h5>Semantics:</h5>
7605<p>The '<tt>llvm.convert.to.fp16</tt>' intrinsic function performs
7606 a conversion from single precision floating point format to half precision
Chris Lattner0cec9c82010-03-15 04:12:21 +0000[diff] [blame]7607 floating point format. The return value is an <tt>i16</tt> which
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]7608 contains the converted number.</p>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]7609
7610<h5>Examples:</h5>
7611<pre>
7612 %res = call i16 @llvm.convert.to.fp16(f32 %a)
7613 store i16 %res, i16* @x, align 2
7614</pre>
7615
7616</div>
7617
7618<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7619<h4>
7620 <a name="int_convert_from_fp16">
7621 '<tt>llvm.convert.from.fp16</tt>' Intrinsic
7622 </a>
7623</h4>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]7624
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7625<div>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]7626
7627<h5>Syntax:</h5>
7628<pre>
7629 declare f32 @llvm.convert.from.fp16(i16 %a)
7630</pre>
7631
7632<h5>Overview:</h5>
7633<p>The '<tt>llvm.convert.from.fp16</tt>' intrinsic function performs
7634 a conversion from half precision floating point format to single precision
7635 floating point format.</p>
7636
7637<h5>Arguments:</h5>
7638<p>The intrinsic function contains single argument - the value to be
7639 converted.</p>
7640
7641<h5>Semantics:</h5>
7642<p>The '<tt>llvm.convert.from.fp16</tt>' intrinsic function performs a
Chris Lattner0cec9c82010-03-15 04:12:21 +0000[diff] [blame]7643 conversion from half single precision floating point format to single
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]7644 precision floating point format. The input half-float value is represented by
7645 an <tt>i16</tt> value.</p>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]7646
7647<h5>Examples:</h5>
7648<pre>
7649 %a = load i16* @x, align 2
7650 %res = call f32 @llvm.convert.from.fp16(i16 %a)
7651</pre>
7652
7653</div>
7654
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7655</div>
7656
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]7657<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7658<h3>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]7659 <a name="int_debugger">Debugger Intrinsics</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7660</h3>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]7661
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7662<div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]7663
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7664<p>The LLVM debugger intrinsics (which all start with <tt>llvm.dbg.</tt>
7665 prefix), are described in
7666 the <a href="SourceLevelDebugging.html#format_common_intrinsics">LLVM Source
7667 Level Debugging</a> document.</p>
7668
7669</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]7670
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]7671<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7672<h3>
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]7673 <a name="int_eh">Exception Handling Intrinsics</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7674</h3>
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]7675
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7676<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7677
7678<p>The LLVM exception handling intrinsics (which all start with
7679 <tt>llvm.eh.</tt> prefix), are described in
7680 the <a href="ExceptionHandling.html#format_common_intrinsics">LLVM Exception
7681 Handling</a> document.</p>
7682
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]7683</div>
7684
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]7685<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7686<h3>
Duncan Sands4a544a72011-09-06 13:37:06 +0000[diff] [blame]7687 <a name="int_trampoline">Trampoline Intrinsics</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7688</h3>
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]7689
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7690<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7691
Duncan Sands4a544a72011-09-06 13:37:06 +0000[diff] [blame]7692<p>These intrinsics make it possible to excise one parameter, marked with
Dan Gohmanff235352010-07-02 23:18:08 +0000[diff] [blame]7693 the <a href="#nest"><tt>nest</tt></a> attribute, from a function.
7694 The result is a callable
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7695 function pointer lacking the nest parameter - the caller does not need to
7696 provide a value for it. Instead, the value to use is stored in advance in a
7697 "trampoline", a block of memory usually allocated on the stack, which also
7698 contains code to splice the nest value into the argument list. This is used
7699 to implement the GCC nested function address extension.</p>
7700
7701<p>For example, if the function is
7702 <tt>i32 f(i8* nest %c, i32 %x, i32 %y)</tt> then the resulting function
7703 pointer has signature <tt>i32 (i32, i32)*</tt>. It can be created as
7704 follows:</p>
7705
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]7706<pre class="doc_code">
Duncan Sandsf7331b32007-09-11 14:10:23 +0000[diff] [blame]7707 %tramp = alloca [10 x i8], align 4 ; size and alignment only correct for X86
7708 %tramp1 = getelementptr [10 x i8]* %tramp, i32 0, i32 0
Duncan Sands4a544a72011-09-06 13:37:06 +0000[diff] [blame]7709 call i8* @llvm.init.trampoline(i8* %tramp1, i8* bitcast (i32 (i8*, i32, i32)* @f to i8*), i8* %nval)
7710 %p = call i8* @llvm.adjust.trampoline(i8* %tramp1)
Duncan Sandsf7331b32007-09-11 14:10:23 +0000[diff] [blame]7711 %fp = bitcast i8* %p to i32 (i32, i32)*
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]7712</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7713
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7714<p>The call <tt>%val = call i32 %fp(i32 %x, i32 %y)</tt> is then equivalent
7715 to <tt>%val = call i32 %f(i8* %nval, i32 %x, i32 %y)</tt>.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7716
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]7717<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7718<h4>
7719 <a name="int_it">
7720 '<tt>llvm.init.trampoline</tt>' Intrinsic
7721 </a>
7722</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7723
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7724<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7725
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]7726<h5>Syntax:</h5>
7727<pre>
Duncan Sands4a544a72011-09-06 13:37:06 +0000[diff] [blame]7728 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]7729</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7730
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]7731<h5>Overview:</h5>
Duncan Sands4a544a72011-09-06 13:37:06 +0000[diff] [blame]7732<p>This fills the memory pointed to by <tt>tramp</tt> with executable code,
7733 turning it into a trampoline.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7734
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]7735<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7736<p>The <tt>llvm.init.trampoline</tt> intrinsic takes three arguments, all
7737 pointers. The <tt>tramp</tt> argument must point to a sufficiently large and
7738 sufficiently aligned block of memory; this memory is written to by the
7739 intrinsic. Note that the size and the alignment are target-specific - LLVM
7740 currently provides no portable way of determining them, so a front-end that
7741 generates this intrinsic needs to have some target-specific knowledge.
7742 The <tt>func</tt> argument must hold a function bitcast to
7743 an <tt>i8*</tt>.</p>
7744
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]7745<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7746<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]7747 dependent code, turning it into a function. Then <tt>tramp</tt> needs to be
7748 passed to <a href="#int_at">llvm.adjust.trampoline</a> to get a pointer
7749 which can be <a href="#int_trampoline">bitcast (to a new function) and
7750 called</a>. The new function's signature is the same as that of
7751 <tt>func</tt> with any arguments marked with the <tt>nest</tt> attribute
7752 removed. At most one such <tt>nest</tt> argument is allowed, and it must be of
7753 pointer type. Calling the new function is equivalent to calling <tt>func</tt>
7754 with the same argument list, but with <tt>nval</tt> used for the missing
7755 <tt>nest</tt> argument. If, after calling <tt>llvm.init.trampoline</tt>, the
7756 memory pointed to by <tt>tramp</tt> is modified, then the effect of any later call
7757 to the returned function pointer is undefined.</p>
7758</div>
7759
7760<!-- _______________________________________________________________________ -->
7761<h4>
7762 <a name="int_at">
7763 '<tt>llvm.adjust.trampoline</tt>' Intrinsic
7764 </a>
7765</h4>
7766
7767<div>
7768
7769<h5>Syntax:</h5>
7770<pre>
7771 declare i8* @llvm.adjust.trampoline(i8* &lt;tramp&gt;)
7772</pre>
7773
7774<h5>Overview:</h5>
7775<p>This performs any required machine-specific adjustment to the address of a
7776 trampoline (passed as <tt>tramp</tt>).</p>
7777
7778<h5>Arguments:</h5>
7779<p><tt>tramp</tt> must point to a block of memory which already has trampoline code
7780 filled in by a previous call to <a href="#int_it"><tt>llvm.init.trampoline</tt>
7781 </a>.</p>
7782
7783<h5>Semantics:</h5>
7784<p>On some architectures the address of the code to be executed needs to be
7785 different to the address where the trampoline is actually stored. This
7786 intrinsic returns the executable address corresponding to <tt>tramp</tt>
7787 after performing the required machine specific adjustments.
7788 The pointer returned can then be <a href="#int_trampoline"> bitcast and
7789 executed</a>.
7790</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7791
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]7792</div>
7793
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7794</div>
7795
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]7796<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7797<h3>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7798 <a name="int_memorymarkers">Memory Use Markers</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7799</h3>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7800
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7801<div>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7802
7803<p>This class of intrinsics exists to information about the lifetime of memory
7804 objects and ranges where variables are immutable.</p>
7805
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7806<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7807<h4>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7808 <a name="int_lifetime_start">'<tt>llvm.lifetime.start</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7809</h4>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7810
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7811<div>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7812
7813<h5>Syntax:</h5>
7814<pre>
7815 declare void @llvm.lifetime.start(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7816</pre>
7817
7818<h5>Overview:</h5>
7819<p>The '<tt>llvm.lifetime.start</tt>' intrinsic specifies the start of a memory
7820 object's lifetime.</p>
7821
7822<h5>Arguments:</h5>
Nick Lewycky321333e2009-10-13 07:57:33 +0000[diff] [blame]7823<p>The first argument is a constant integer representing the size of the
7824 object, or -1 if it is variable sized. The second argument is a pointer to
7825 the object.</p>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7826
7827<h5>Semantics:</h5>
7828<p>This intrinsic indicates that before this point in the code, the value of the
7829 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]7830 never be used and has an undefined value. A load from the pointer that
7831 precedes this intrinsic can be replaced with
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7832 <tt>'<a href="#undefvalues">undef</a>'</tt>.</p>
7833
7834</div>
7835
7836<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7837<h4>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7838 <a name="int_lifetime_end">'<tt>llvm.lifetime.end</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7839</h4>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7840
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7841<div>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7842
7843<h5>Syntax:</h5>
7844<pre>
7845 declare void @llvm.lifetime.end(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7846</pre>
7847
7848<h5>Overview:</h5>
7849<p>The '<tt>llvm.lifetime.end</tt>' intrinsic specifies the end of a memory
7850 object's lifetime.</p>
7851
7852<h5>Arguments:</h5>
Nick Lewycky321333e2009-10-13 07:57:33 +0000[diff] [blame]7853<p>The first argument is a constant integer representing the size of the
7854 object, or -1 if it is variable sized. The second argument is a pointer to
7855 the object.</p>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7856
7857<h5>Semantics:</h5>
7858<p>This intrinsic indicates that after this point in the code, the value of the
7859 memory pointed to by <tt>ptr</tt> is dead. This means that it is known to
7860 never be used and has an undefined value. Any stores into the memory object
7861 following this intrinsic may be removed as dead.
7862
7863</div>
7864
7865<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7866<h4>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7867 <a name="int_invariant_start">'<tt>llvm.invariant.start</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7868</h4>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7869
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7870<div>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7871
7872<h5>Syntax:</h5>
7873<pre>
Nick Lewycky29b6cb42010-11-30 04:13:41 +0000[diff] [blame]7874 declare {}* @llvm.invariant.start(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7875</pre>
7876
7877<h5>Overview:</h5>
7878<p>The '<tt>llvm.invariant.start</tt>' intrinsic specifies that the contents of
7879 a memory object will not change.</p>
7880
7881<h5>Arguments:</h5>
Nick Lewycky321333e2009-10-13 07:57:33 +0000[diff] [blame]7882<p>The first argument is a constant integer representing the size of the
7883 object, or -1 if it is variable sized. The second argument is a pointer to
7884 the object.</p>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7885
7886<h5>Semantics:</h5>
7887<p>This intrinsic indicates that until an <tt>llvm.invariant.end</tt> that uses
7888 the return value, the referenced memory location is constant and
7889 unchanging.</p>
7890
7891</div>
7892
7893<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7894<h4>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7895 <a name="int_invariant_end">'<tt>llvm.invariant.end</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7896</h4>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7897
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7898<div>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7899
7900<h5>Syntax:</h5>
7901<pre>
7902 declare void @llvm.invariant.end({}* &lt;start&gt;, i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7903</pre>
7904
7905<h5>Overview:</h5>
7906<p>The '<tt>llvm.invariant.end</tt>' intrinsic specifies that the contents of
7907 a memory object are mutable.</p>
7908
7909<h5>Arguments:</h5>
7910<p>The first argument is the matching <tt>llvm.invariant.start</tt> intrinsic.
Nick Lewycky321333e2009-10-13 07:57:33 +0000[diff] [blame]7911 The second argument is a constant integer representing the size of the
7912 object, or -1 if it is variable sized and the third argument is a pointer
7913 to the object.</p>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7914
7915<h5>Semantics:</h5>
7916<p>This intrinsic indicates that the memory is mutable again.</p>
7917
7918</div>
7919
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7920</div>
7921
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7922<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7923<h3>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]7924 <a name="int_general">General Intrinsics</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7925</h3>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]7926
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7927<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7928
7929<p>This class of intrinsics is designed to be generic and has no specific
7930 purpose.</p>
7931
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]7932<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7933<h4>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]7934 <a name="int_var_annotation">'<tt>llvm.var.annotation</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7935</h4>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]7936
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7937<div>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]7938
7939<h5>Syntax:</h5>
7940<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7941 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]7942</pre>
7943
7944<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7945<p>The '<tt>llvm.var.annotation</tt>' intrinsic.</p>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]7946
7947<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7948<p>The first argument is a pointer to a value, the second is a pointer to a
7949 global string, the third is a pointer to a global string which is the source
7950 file name, and the last argument is the line number.</p>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]7951
7952<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7953<p>This intrinsic allows annotation of local variables with arbitrary strings.
7954 This can be useful for special purpose optimizations that want to look for
John Criswelle865c032011-08-19 16:57:55 +0000[diff] [blame]7955 these annotations. These have no other defined use; they are ignored by code
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7956 generation and optimization.</p>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]7957
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]7958</div>
7959
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7960<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7961<h4>
Tanya Lattnere1a8da02007-09-21 23:57:59 +0000[diff] [blame]7962 <a name="int_annotation">'<tt>llvm.annotation.*</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7963</h4>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7964
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7965<div>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7966
7967<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7968<p>This is an overloaded intrinsic. You can use '<tt>llvm.annotation</tt>' on
7969 any integer bit width.</p>
7970
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7971<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7972 declare i8 @llvm.annotation.i8(i8 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
7973 declare i16 @llvm.annotation.i16(i16 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
7974 declare i32 @llvm.annotation.i32(i32 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
7975 declare i64 @llvm.annotation.i64(i64 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
7976 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]7977</pre>
7978
7979<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7980<p>The '<tt>llvm.annotation</tt>' intrinsic.</p>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7981
7982<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7983<p>The first argument is an integer value (result of some expression), the
7984 second is a pointer to a global string, the third is a pointer to a global
7985 string which is the source file name, and the last argument is the line
7986 number. It returns the value of the first argument.</p>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7987
7988<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7989<p>This intrinsic allows annotations to be put on arbitrary expressions with
7990 arbitrary strings. This can be useful for special purpose optimizations that
John Criswelle865c032011-08-19 16:57:55 +0000[diff] [blame]7991 want to look for these annotations. These have no other defined use; they
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7992 are ignored by code generation and optimization.</p>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7993
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7994</div>
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]7995
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]7996<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7997<h4>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]7998 <a name="int_trap">'<tt>llvm.trap</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7999</h4>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]8000
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8001<div>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]8002
8003<h5>Syntax:</h5>
8004<pre>
8005 declare void @llvm.trap()
8006</pre>
8007
8008<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8009<p>The '<tt>llvm.trap</tt>' intrinsic.</p>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]8010
8011<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8012<p>None.</p>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]8013
8014<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8015<p>This intrinsics is lowered to the target dependent trap instruction. If the
8016 target does not have a trap instruction, this intrinsic will be lowered to
8017 the call of the <tt>abort()</tt> function.</p>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]8018
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]8019</div>
8020
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]8021<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8022<h4>
Misha Brukmandccb0252008-11-22 23:55:29 +0000[diff] [blame]8023 <a name="int_stackprotector">'<tt>llvm.stackprotector</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8024</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8025
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8026<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8027
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]8028<h5>Syntax:</h5>
8029<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]8030 declare void @llvm.stackprotector(i8* &lt;guard&gt;, i8** &lt;slot&gt;)
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]8031</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8032
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]8033<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8034<p>The <tt>llvm.stackprotector</tt> intrinsic takes the <tt>guard</tt> and
8035 stores it onto the stack at <tt>slot</tt>. The stack slot is adjusted to
8036 ensure that it is placed on the stack before local variables.</p>
8037
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]8038<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8039<p>The <tt>llvm.stackprotector</tt> intrinsic requires two pointer
8040 arguments. The first argument is the value loaded from the stack
8041 guard <tt>@__stack_chk_guard</tt>. The second variable is an <tt>alloca</tt>
8042 that has enough space to hold the value of the guard.</p>
8043
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]8044<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8045<p>This intrinsic causes the prologue/epilogue inserter to force the position of
8046 the <tt>AllocaInst</tt> stack slot to be before local variables on the
8047 stack. This is to ensure that if a local variable on the stack is
8048 overwritten, it will destroy the value of the guard. When the function exits,
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]8049 the guard on the stack is checked against the original guard. If they are
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8050 different, then the program aborts by calling the <tt>__stack_chk_fail()</tt>
8051 function.</p>
8052
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]8053</div>
8054
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]8055<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8056<h4>
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]8057 <a name="int_objectsize">'<tt>llvm.objectsize</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8058</h4>
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]8059
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8060<div>
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]8061
8062<h5>Syntax:</h5>
8063<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]8064 declare i32 @llvm.objectsize.i32(i8* &lt;object&gt;, i1 &lt;type&gt;)
8065 declare i64 @llvm.objectsize.i64(i8* &lt;object&gt;, i1 &lt;type&gt;)
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]8066</pre>
8067
8068<h5>Overview:</h5>
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]8069<p>The <tt>llvm.objectsize</tt> intrinsic is designed to provide information to
8070 the optimizers to determine at compile time whether a) an operation (like
8071 memcpy) will overflow a buffer that corresponds to an object, or b) that a
8072 runtime check for overflow isn't necessary. An object in this context means
8073 an allocation of a specific class, structure, array, or other object.</p>
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]8074
8075<h5>Arguments:</h5>
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]8076<p>The <tt>llvm.objectsize</tt> intrinsic takes two arguments. The first
Eric Christopher8295a0a2009-12-23 00:29:49 +0000[diff] [blame]8077 argument is a pointer to or into the <tt>object</tt>. The second argument
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]8078 is a boolean 0 or 1. This argument determines whether you want the
8079 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]8080 1, variables are not allowed.</p>
8081
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]8082<h5>Semantics:</h5>
8083<p>The <tt>llvm.objectsize</tt> intrinsic is lowered to either a constant
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]8084 representing the size of the object concerned, or <tt>i32/i64 -1 or 0</tt>,
8085 depending on the <tt>type</tt> argument, if the size cannot be determined at
8086 compile time.</p>
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]8087
8088</div>
8089
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8090</div>
8091
8092</div>
8093
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]8094<!-- *********************************************************************** -->
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]8095<hr>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]8096<address>
8097 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
Misha Brukman44408702008-12-11 17:34:48 +0000[diff] [blame]8098 src="http://jigsaw.w3.org/css-validator/images/vcss-blue" alt="Valid CSS"></a>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]8099 <a href="http://validator.w3.org/check/referer"><img
Misha Brukman44408702008-12-11 17:34:48 +0000[diff] [blame]8100 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]8101
8102 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
NAKAMURA Takumib9a33632011-04-09 02:13:37 +0000[diff] [blame]8103 <a href="http://llvm.org/">The LLVM Compiler Infrastructure</a><br>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]8104 Last modified: $Date$
8105</address>
Chris Lattnerc7d3ab32008-01-04 04:33:49 +0000[diff] [blame]8106
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]8107</body>
8108</html>