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gerrit-public.fairphone.software / platform / external / llvm / 5cdc51ea7bd13ce5ba0df90b681e8bf327f11b58 / . / docs / LangRef.html
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4<head>
5 <title>LLVM Assembly Language Reference Manual</title>
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7 <meta name="author" content="Chris Lattner">
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]8 <meta name="description"
Reid Spencer3921c742004-08-26 20:44:00 +0000[diff] [blame]9 content="LLVM Assembly Language Reference Manual.">
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]10 <link rel="stylesheet" href="llvm.css" type="text/css">
11</head>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]12
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]13<body>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]14
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]15<h1>LLVM Language Reference Manual</h1>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]16<ol>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]17 <li><a href="#abstract">Abstract</a></li>
18 <li><a href="#introduction">Introduction</a></li>
19 <li><a href="#identifiers">Identifiers</a></li>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]20 <li><a href="#highlevel">High Level Structure</a>
21 <ol>
22 <li><a href="#modulestructure">Module Structure</a></li>
Bill Wendling3d10a5a2009-07-20 01:03:30 +0000[diff] [blame]23 <li><a href="#linkage">Linkage Types</a>
24 <ol>
Bill Wendling987e7eb2009-07-20 02:41:50 +0000[diff] [blame]25 <li><a href="#linkage_private">'<tt>private</tt>' Linkage</a></li>
26 <li><a href="#linkage_linker_private">'<tt>linker_private</tt>' Linkage</a></li>
Bill Wendling5e721d72010-07-01 21:55:59 +0000[diff] [blame]27 <li><a href="#linkage_linker_private_weak">'<tt>linker_private_weak</tt>' Linkage</a></li>
Bill Wendling55ae5152010-08-20 22:05:50 +0000[diff] [blame]28 <li><a href="#linkage_linker_private_weak_def_auto">'<tt>linker_private_weak_def_auto</tt>' Linkage</a></li>
Bill Wendling987e7eb2009-07-20 02:41:50 +0000[diff] [blame]29 <li><a href="#linkage_internal">'<tt>internal</tt>' Linkage</a></li>
30 <li><a href="#linkage_available_externally">'<tt>available_externally</tt>' Linkage</a></li>
31 <li><a href="#linkage_linkonce">'<tt>linkonce</tt>' Linkage</a></li>
32 <li><a href="#linkage_common">'<tt>common</tt>' Linkage</a></li>
33 <li><a href="#linkage_weak">'<tt>weak</tt>' Linkage</a></li>
34 <li><a href="#linkage_appending">'<tt>appending</tt>' Linkage</a></li>
35 <li><a href="#linkage_externweak">'<tt>extern_weak</tt>' Linkage</a></li>
Chris Lattner5a2d8752009-10-10 18:26:06 +0000[diff] [blame]36 <li><a href="#linkage_linkonce_odr">'<tt>linkonce_odr</tt>' Linkage</a></li>
Bill Wendling987e7eb2009-07-20 02:41:50 +0000[diff] [blame]37 <li><a href="#linkage_weak">'<tt>weak_odr</tt>' Linkage</a></li>
Bill Wendlingf7f06102011-10-11 06:41:28 +0000[diff] [blame]38 <li><a href="#linkage_external">'<tt>external</tt>' Linkage</a></li>
Bill Wendling987e7eb2009-07-20 02:41:50 +0000[diff] [blame]39 <li><a href="#linkage_dllimport">'<tt>dllimport</tt>' Linkage</a></li>
40 <li><a href="#linkage_dllexport">'<tt>dllexport</tt>' Linkage</a></li>
Bill Wendling3d10a5a2009-07-20 01:03:30 +0000[diff] [blame]41 </ol>
42 </li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]43 <li><a href="#callingconv">Calling Conventions</a></li>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]44 <li><a href="#namedtypes">Named Types</a></li>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]45 <li><a href="#globalvars">Global Variables</a></li>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]46 <li><a href="#functionstructure">Functions</a></li>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]47 <li><a href="#aliasstructure">Aliases</a></li>
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]48 <li><a href="#namedmetadatastructure">Named Metadata</a></li>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]49 <li><a href="#paramattrs">Parameter Attributes</a></li>
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]50 <li><a href="#fnattrs">Function Attributes</a></li>
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]51 <li><a href="#gc">Garbage Collector Names</a></li>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]52 <li><a href="#moduleasm">Module-Level Inline Assembly</a></li>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]53 <li><a href="#datalayout">Data Layout</a></li>
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]54 <li><a href="#pointeraliasing">Pointer Aliasing Rules</a></li>
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]55 <li><a href="#volatile">Volatile Memory Accesses</a></li>
Eli Friedman5b60e1b2011-07-20 21:35:53 +0000[diff] [blame]56 <li><a href="#memmodel">Memory Model for Concurrent Operations</a></li>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]57 <li><a href="#ordering">Atomic Memory Ordering Constraints</a></li>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]58 </ol>
59 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]60 <li><a href="#typesystem">Type System</a>
61 <ol>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]62 <li><a href="#t_classifications">Type Classifications</a></li>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]63 <li><a href="#t_primitive">Primitive Types</a>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]64 <ol>
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]65 <li><a href="#t_integer">Integer Type</a></li>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]66 <li><a href="#t_floating">Floating Point Types</a></li>
Dale Johannesen21fe99b2010-10-01 00:48:59 +0000[diff] [blame]67 <li><a href="#t_x86mmx">X86mmx Type</a></li>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]68 <li><a href="#t_void">Void Type</a></li>
69 <li><a href="#t_label">Label Type</a></li>
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]70 <li><a href="#t_metadata">Metadata Type</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]71 </ol>
72 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]73 <li><a href="#t_derived">Derived Types</a>
74 <ol>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]75 <li><a href="#t_aggregate">Aggregate Types</a>
76 <ol>
77 <li><a href="#t_array">Array Type</a></li>
78 <li><a href="#t_struct">Structure Type</a></li>
Chris Lattner628ed392011-07-23 19:59:08 +0000[diff] [blame]79 <li><a href="#t_opaque">Opaque Structure Types</a></li>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]80 <li><a href="#t_vector">Vector Type</a></li>
81 </ol>
82 </li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]83 <li><a href="#t_function">Function Type</a></li>
84 <li><a href="#t_pointer">Pointer Type</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]85 </ol>
86 </li>
87 </ol>
88 </li>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]89 <li><a href="#constants">Constants</a>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]90 <ol>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]91 <li><a href="#simpleconstants">Simple Constants</a></li>
Chris Lattner70882792009-02-28 18:32:25 +0000[diff] [blame]92 <li><a href="#complexconstants">Complex Constants</a></li>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]93 <li><a href="#globalconstants">Global Variable and Function Addresses</a></li>
94 <li><a href="#undefvalues">Undefined Values</a></li>
Dan Gohmanbfb056d2011-12-06 03:18:47 +0000[diff] [blame]95 <li><a href="#poisonvalues">Poison Values</a></li>
Chris Lattnerf9d078e2009-10-27 21:19:13 +0000[diff] [blame]96 <li><a href="#blockaddress">Addresses of Basic Blocks</a></li>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]97 <li><a href="#constantexprs">Constant Expressions</a></li>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]98 </ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]99 </li>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]100 <li><a href="#othervalues">Other Values</a>
101 <ol>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]102 <li><a href="#inlineasm">Inline Assembler Expressions</a></li>
Peter Collingbourne249d9532011-10-27 19:19:07 +0000[diff] [blame]103 <li><a href="#metadata">Metadata Nodes and Metadata Strings</a>
104 <ol>
105 <li><a href="#tbaa">'<tt>tbaa</tt>' Metadata</a></li>
Peter Collingbourne999f90b2011-10-27 19:19:14 +0000[diff] [blame]106 <li><a href="#fpaccuracy">'<tt>fpaccuracy</tt>' Metadata</a></li>
Peter Collingbourne249d9532011-10-27 19:19:07 +0000[diff] [blame]107 </ol>
108 </li>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]109 </ol>
110 </li>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]111 <li><a href="#intrinsic_globals">Intrinsic Global Variables</a>
112 <ol>
113 <li><a href="#intg_used">The '<tt>llvm.used</tt>' Global Variable</a></li>
Chris Lattner401e10c2009-07-20 06:14:25 +0000[diff] [blame]114 <li><a href="#intg_compiler_used">The '<tt>llvm.compiler.used</tt>'
115 Global Variable</a></li>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]116 <li><a href="#intg_global_ctors">The '<tt>llvm.global_ctors</tt>'
117 Global Variable</a></li>
118 <li><a href="#intg_global_dtors">The '<tt>llvm.global_dtors</tt>'
119 Global Variable</a></li>
120 </ol>
121 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]122 <li><a href="#instref">Instruction Reference</a>
123 <ol>
124 <li><a href="#terminators">Terminator Instructions</a>
125 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]126 <li><a href="#i_ret">'<tt>ret</tt>' Instruction</a></li>
127 <li><a href="#i_br">'<tt>br</tt>' Instruction</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]128 <li><a href="#i_switch">'<tt>switch</tt>' Instruction</a></li>
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]129 <li><a href="#i_indirectbr">'<tt>indirectbr</tt>' Instruction</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]130 <li><a href="#i_invoke">'<tt>invoke</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]131 <li><a href="#i_unwind">'<tt>unwind</tt>' Instruction</a></li>
Bill Wendlingdccc03b2011-07-31 06:30:59 +0000[diff] [blame]132 <li><a href="#i_resume">'<tt>resume</tt>' Instruction</a></li>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]133 <li><a href="#i_unreachable">'<tt>unreachable</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]134 </ol>
135 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]136 <li><a href="#binaryops">Binary Operations</a>
137 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]138 <li><a href="#i_add">'<tt>add</tt>' Instruction</a></li>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]139 <li><a href="#i_fadd">'<tt>fadd</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]140 <li><a href="#i_sub">'<tt>sub</tt>' Instruction</a></li>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]141 <li><a href="#i_fsub">'<tt>fsub</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]142 <li><a href="#i_mul">'<tt>mul</tt>' Instruction</a></li>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]143 <li><a href="#i_fmul">'<tt>fmul</tt>' Instruction</a></li>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]144 <li><a href="#i_udiv">'<tt>udiv</tt>' Instruction</a></li>
145 <li><a href="#i_sdiv">'<tt>sdiv</tt>' Instruction</a></li>
146 <li><a href="#i_fdiv">'<tt>fdiv</tt>' Instruction</a></li>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]147 <li><a href="#i_urem">'<tt>urem</tt>' Instruction</a></li>
148 <li><a href="#i_srem">'<tt>srem</tt>' Instruction</a></li>
149 <li><a href="#i_frem">'<tt>frem</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]150 </ol>
151 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]152 <li><a href="#bitwiseops">Bitwise Binary Operations</a>
153 <ol>
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]154 <li><a href="#i_shl">'<tt>shl</tt>' Instruction</a></li>
155 <li><a href="#i_lshr">'<tt>lshr</tt>' Instruction</a></li>
156 <li><a href="#i_ashr">'<tt>ashr</tt>' Instruction</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]157 <li><a href="#i_and">'<tt>and</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]158 <li><a href="#i_or">'<tt>or</tt>' Instruction</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]159 <li><a href="#i_xor">'<tt>xor</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]160 </ol>
161 </li>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]162 <li><a href="#vectorops">Vector Operations</a>
163 <ol>
164 <li><a href="#i_extractelement">'<tt>extractelement</tt>' Instruction</a></li>
165 <li><a href="#i_insertelement">'<tt>insertelement</tt>' Instruction</a></li>
166 <li><a href="#i_shufflevector">'<tt>shufflevector</tt>' Instruction</a></li>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]167 </ol>
168 </li>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]169 <li><a href="#aggregateops">Aggregate Operations</a>
170 <ol>
171 <li><a href="#i_extractvalue">'<tt>extractvalue</tt>' Instruction</a></li>
172 <li><a href="#i_insertvalue">'<tt>insertvalue</tt>' Instruction</a></li>
173 </ol>
174 </li>
Chris Lattner884a9702006-08-15 00:45:58 +0000[diff] [blame]175 <li><a href="#memoryops">Memory Access and Addressing Operations</a>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]176 <ol>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]177 <li><a href="#i_alloca">'<tt>alloca</tt>' Instruction</a></li>
178 <li><a href="#i_load">'<tt>load</tt>' Instruction</a></li>
179 <li><a href="#i_store">'<tt>store</tt>' Instruction</a></li>
180 <li><a href="#i_fence">'<tt>fence</tt>' Instruction</a></li>
181 <li><a href="#i_cmpxchg">'<tt>cmpxchg</tt>' Instruction</a></li>
182 <li><a href="#i_atomicrmw">'<tt>atomicrmw</tt>' Instruction</a></li>
Robert Bocchino7b81c752006-02-17 21:18:08 +0000[diff] [blame]183 <li><a href="#i_getelementptr">'<tt>getelementptr</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]184 </ol>
185 </li>
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]186 <li><a href="#convertops">Conversion Operations</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]187 <ol>
188 <li><a href="#i_trunc">'<tt>trunc .. to</tt>' Instruction</a></li>
189 <li><a href="#i_zext">'<tt>zext .. to</tt>' Instruction</a></li>
190 <li><a href="#i_sext">'<tt>sext .. to</tt>' Instruction</a></li>
191 <li><a href="#i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a></li>
192 <li><a href="#i_fpext">'<tt>fpext .. to</tt>' Instruction</a></li>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]193 <li><a href="#i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a></li>
194 <li><a href="#i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a></li>
195 <li><a href="#i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a></li>
196 <li><a href="#i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a></li>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]197 <li><a href="#i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a></li>
198 <li><a href="#i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a></li>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]199 <li><a href="#i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a></li>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]200 </ol>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]201 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]202 <li><a href="#otherops">Other Operations</a>
203 <ol>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]204 <li><a href="#i_icmp">'<tt>icmp</tt>' Instruction</a></li>
205 <li><a href="#i_fcmp">'<tt>fcmp</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]206 <li><a href="#i_phi">'<tt>phi</tt>' Instruction</a></li>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]207 <li><a href="#i_select">'<tt>select</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]208 <li><a href="#i_call">'<tt>call</tt>' Instruction</a></li>
Chris Lattnerfb6977d2006-01-13 23:26:01 +0000[diff] [blame]209 <li><a href="#i_va_arg">'<tt>va_arg</tt>' Instruction</a></li>
Bill Wendlingf78faf82011-08-02 21:52:38 +0000[diff] [blame]210 <li><a href="#i_landingpad">'<tt>landingpad</tt>' Instruction</a></li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]211 </ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]212 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]213 </ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]214 </li>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]215 <li><a href="#intrinsics">Intrinsic Functions</a>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]216 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]217 <li><a href="#int_varargs">Variable Argument Handling Intrinsics</a>
218 <ol>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]219 <li><a href="#int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a></li>
220 <li><a href="#int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a></li>
221 <li><a href="#int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]222 </ol>
223 </li>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]224 <li><a href="#int_gc">Accurate Garbage Collection Intrinsics</a>
225 <ol>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]226 <li><a href="#int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a></li>
227 <li><a href="#int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a></li>
228 <li><a href="#int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a></li>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]229 </ol>
230 </li>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]231 <li><a href="#int_codegen">Code Generator Intrinsics</a>
232 <ol>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]233 <li><a href="#int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a></li>
234 <li><a href="#int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a></li>
235 <li><a href="#int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a></li>
236 <li><a href="#int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a></li>
237 <li><a href="#int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a></li>
238 <li><a href="#int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a></li>
Dan Gohman31f1af12010-05-26 21:56:15 +0000[diff] [blame]239 <li><a href="#int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a></li>
John Criswell7123e272004-04-09 16:43:20 +0000[diff] [blame]240 </ol>
241 </li>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]242 <li><a href="#int_libc">Standard C Library Intrinsics</a>
243 <ol>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]244 <li><a href="#int_memcpy">'<tt>llvm.memcpy.*</tt>' Intrinsic</a></li>
245 <li><a href="#int_memmove">'<tt>llvm.memmove.*</tt>' Intrinsic</a></li>
246 <li><a href="#int_memset">'<tt>llvm.memset.*</tt>' Intrinsic</a></li>
247 <li><a href="#int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a></li>
248 <li><a href="#int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a></li>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]249 <li><a href="#int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a></li>
250 <li><a href="#int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a></li>
251 <li><a href="#int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a></li>
Dan Gohman08b280b2011-05-27 00:36:31 +0000[diff] [blame]252 <li><a href="#int_exp">'<tt>llvm.exp.*</tt>' Intrinsic</a></li>
253 <li><a href="#int_log">'<tt>llvm.log.*</tt>' Intrinsic</a></li>
Cameron Zwarich33390842011-07-08 21:39:21 +0000[diff] [blame]254 <li><a href="#int_fma">'<tt>llvm.fma.*</tt>' Intrinsic</a></li>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]255 </ol>
256 </li>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]257 <li><a href="#int_manip">Bit Manipulation Intrinsics</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]258 <ol>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]259 <li><a href="#int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a></li>
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]260 <li><a href="#int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic </a></li>
261 <li><a href="#int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic </a></li>
262 <li><a href="#int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic </a></li>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]263 </ol>
264 </li>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]265 <li><a href="#int_overflow">Arithmetic with Overflow Intrinsics</a>
266 <ol>
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]267 <li><a href="#int_sadd_overflow">'<tt>llvm.sadd.with.overflow.*</tt> Intrinsics</a></li>
268 <li><a href="#int_uadd_overflow">'<tt>llvm.uadd.with.overflow.*</tt> Intrinsics</a></li>
269 <li><a href="#int_ssub_overflow">'<tt>llvm.ssub.with.overflow.*</tt> Intrinsics</a></li>
270 <li><a href="#int_usub_overflow">'<tt>llvm.usub.with.overflow.*</tt> Intrinsics</a></li>
271 <li><a href="#int_smul_overflow">'<tt>llvm.smul.with.overflow.*</tt> Intrinsics</a></li>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]272 <li><a href="#int_umul_overflow">'<tt>llvm.umul.with.overflow.*</tt> Intrinsics</a></li>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]273 </ol>
274 </li>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]275 <li><a href="#int_fp16">Half Precision Floating Point Intrinsics</a>
276 <ol>
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]277 <li><a href="#int_convert_to_fp16">'<tt>llvm.convert.to.fp16</tt>' Intrinsic</a></li>
278 <li><a href="#int_convert_from_fp16">'<tt>llvm.convert.from.fp16</tt>' Intrinsic</a></li>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]279 </ol>
280 </li>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]281 <li><a href="#int_debugger">Debugger intrinsics</a></li>
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]282 <li><a href="#int_eh">Exception Handling intrinsics</a></li>
Duncan Sands4a544a72011-09-06 13:37:06 +0000[diff] [blame]283 <li><a href="#int_trampoline">Trampoline Intrinsics</a>
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]284 <ol>
285 <li><a href="#int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a></li>
Duncan Sands4a544a72011-09-06 13:37:06 +0000[diff] [blame]286 <li><a href="#int_at">'<tt>llvm.adjust.trampoline</tt>' Intrinsic</a></li>
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]287 </ol>
288 </li>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]289 <li><a href="#int_memorymarkers">Memory Use Markers</a>
290 <ol>
Jakub Staszak8e1b12a2011-12-04 20:44:25 +0000[diff] [blame]291 <li><a href="#int_lifetime_start">'<tt>llvm.lifetime.start</tt>' Intrinsic</a></li>
292 <li><a href="#int_lifetime_end">'<tt>llvm.lifetime.end</tt>' Intrinsic</a></li>
293 <li><a href="#int_invariant_start">'<tt>llvm.invariant.start</tt>' Intrinsic</a></li>
294 <li><a href="#int_invariant_end">'<tt>llvm.invariant.end</tt>' Intrinsic</a></li>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]295 </ol>
296 </li>
Reid Spencer20677642007-07-20 19:59:11 +0000[diff] [blame]297 <li><a href="#int_general">General intrinsics</a>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]298 <ol>
Reid Spencer20677642007-07-20 19:59:11 +0000[diff] [blame]299 <li><a href="#int_var_annotation">
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]300 '<tt>llvm.var.annotation</tt>' Intrinsic</a></li>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]301 <li><a href="#int_annotation">
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]302 '<tt>llvm.annotation.*</tt>' Intrinsic</a></li>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]303 <li><a href="#int_trap">
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]304 '<tt>llvm.trap</tt>' Intrinsic</a></li>
305 <li><a href="#int_stackprotector">
306 '<tt>llvm.stackprotector</tt>' Intrinsic</a></li>
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]307 <li><a href="#int_objectsize">
308 '<tt>llvm.objectsize</tt>' Intrinsic</a></li>
Jakub Staszakb170e2d2011-12-04 18:29:26 +0000[diff] [blame]309 <li><a href="#int_expect">
310 '<tt>llvm.expect</tt>' Intrinsic</a></li>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]311 </ol>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]312 </li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]313 </ol>
314 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]315</ol>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]316
317<div class="doc_author">
318 <p>Written by <a href="mailto:sabre@nondot.org">Chris Lattner</a>
319 and <a href="mailto:vadve@cs.uiuc.edu">Vikram Adve</a></p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]320</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]321
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]322<!-- *********************************************************************** -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]323<h2><a name="abstract">Abstract</a></h2>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]324<!-- *********************************************************************** -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]325
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]326<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]327
328<p>This document is a reference manual for the LLVM assembly language. LLVM is
329 a Static Single Assignment (SSA) based representation that provides type
330 safety, low-level operations, flexibility, and the capability of representing
331 'all' high-level languages cleanly. It is the common code representation
332 used throughout all phases of the LLVM compilation strategy.</p>
333
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]334</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]335
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]336<!-- *********************************************************************** -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]337<h2><a name="introduction">Introduction</a></h2>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]338<!-- *********************************************************************** -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]339
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]340<div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]341
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]342<p>The LLVM code representation is designed to be used in three different forms:
343 as an in-memory compiler IR, as an on-disk bitcode representation (suitable
344 for fast loading by a Just-In-Time compiler), and as a human readable
345 assembly language representation. This allows LLVM to provide a powerful
346 intermediate representation for efficient compiler transformations and
347 analysis, while providing a natural means to debug and visualize the
348 transformations. The three different forms of LLVM are all equivalent. This
349 document describes the human readable representation and notation.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]350
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]351<p>The LLVM representation aims to be light-weight and low-level while being
352 expressive, typed, and extensible at the same time. It aims to be a
353 "universal IR" of sorts, by being at a low enough level that high-level ideas
354 may be cleanly mapped to it (similar to how microprocessors are "universal
355 IR's", allowing many source languages to be mapped to them). By providing
356 type information, LLVM can be used as the target of optimizations: for
357 example, through pointer analysis, it can be proven that a C automatic
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]358 variable is never accessed outside of the current function, allowing it to
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]359 be promoted to a simple SSA value instead of a memory location.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]360
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]361<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]362<h4>
363 <a name="wellformed">Well-Formedness</a>
364</h4>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]365
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]366<div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]367
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]368<p>It is important to note that this document describes 'well formed' LLVM
369 assembly language. There is a difference between what the parser accepts and
370 what is considered 'well formed'. For example, the following instruction is
371 syntactically okay, but not well formed:</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]372
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]373<pre class="doc_code">
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]374%x = <a href="#i_add">add</a> i32 1, %x
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]375</pre>
376
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]377<p>because the definition of <tt>%x</tt> does not dominate all of its uses. The
378 LLVM infrastructure provides a verification pass that may be used to verify
379 that an LLVM module is well formed. This pass is automatically run by the
380 parser after parsing input assembly and by the optimizer before it outputs
381 bitcode. The violations pointed out by the verifier pass indicate bugs in
382 transformation passes or input to the parser.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]383
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]384</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]385
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]386</div>
387
Chris Lattnercc689392007-10-03 17:34:29 +0000[diff] [blame]388<!-- Describe the typesetting conventions here. -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]389
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]390<!-- *********************************************************************** -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]391<h2><a name="identifiers">Identifiers</a></h2>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]392<!-- *********************************************************************** -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]393
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]394<div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]395
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]396<p>LLVM identifiers come in two basic types: global and local. Global
397 identifiers (functions, global variables) begin with the <tt>'@'</tt>
398 character. Local identifiers (register names, types) begin with
399 the <tt>'%'</tt> character. Additionally, there are three different formats
400 for identifiers, for different purposes:</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]401
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]402<ol>
Reid Spencer2c452282007-08-07 14:34:28 +0000[diff] [blame]403 <li>Named values are represented as a string of characters with their prefix.
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]404 For example, <tt>%foo</tt>, <tt>@DivisionByZero</tt>,
405 <tt>%a.really.long.identifier</tt>. The actual regular expression used is
406 '<tt>[%@][a-zA-Z$._][a-zA-Z$._0-9]*</tt>'. Identifiers which require
407 other characters in their names can be surrounded with quotes. Special
408 characters may be escaped using <tt>"\xx"</tt> where <tt>xx</tt> is the
409 ASCII code for the character in hexadecimal. In this way, any character
410 can be used in a name value, even quotes themselves.</li>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]411
Reid Spencer2c452282007-08-07 14:34:28 +0000[diff] [blame]412 <li>Unnamed values are represented as an unsigned numeric value with their
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]413 prefix. For example, <tt>%12</tt>, <tt>@2</tt>, <tt>%44</tt>.</li>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]414
Reid Spencercc16dc32004-12-09 18:02:53 +0000[diff] [blame]415 <li>Constants, which are described in a <a href="#constants">section about
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]416 constants</a>, below.</li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]417</ol>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]418
Reid Spencer2c452282007-08-07 14:34:28 +0000[diff] [blame]419<p>LLVM requires that values start with a prefix for two reasons: Compilers
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]420 don't need to worry about name clashes with reserved words, and the set of
421 reserved words may be expanded in the future without penalty. Additionally,
422 unnamed identifiers allow a compiler to quickly come up with a temporary
423 variable without having to avoid symbol table conflicts.</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]424
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]425<p>Reserved words in LLVM are very similar to reserved words in other
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]426 languages. There are keywords for different opcodes
427 ('<tt><a href="#i_add">add</a></tt>',
428 '<tt><a href="#i_bitcast">bitcast</a></tt>',
429 '<tt><a href="#i_ret">ret</a></tt>', etc...), for primitive type names
430 ('<tt><a href="#t_void">void</a></tt>',
431 '<tt><a href="#t_primitive">i32</a></tt>', etc...), and others. These
432 reserved words cannot conflict with variable names, because none of them
433 start with a prefix character (<tt>'%'</tt> or <tt>'@'</tt>).</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]434
435<p>Here is an example of LLVM code to multiply the integer variable
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]436 '<tt>%X</tt>' by 8:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]437
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]438<p>The easy way:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]439
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]440<pre class="doc_code">
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]441%result = <a href="#i_mul">mul</a> i32 %X, 8
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]442</pre>
443
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]444<p>After strength reduction:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]445
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]446<pre class="doc_code">
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]447%result = <a href="#i_shl">shl</a> i32 %X, i8 3
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]448</pre>
449
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]450<p>And the hard way:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]451
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]452<pre class="doc_code">
Gabor Greifec58f752009-10-28 13:05:07 +0000[diff] [blame]453%0 = <a href="#i_add">add</a> i32 %X, %X <i>; yields {i32}:%0</i>
454%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]455%result = <a href="#i_add">add</a> i32 %1, %1
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]456</pre>
457
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]458<p>This last way of multiplying <tt>%X</tt> by 8 illustrates several important
459 lexical features of LLVM:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]460
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]461<ol>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]462 <li>Comments are delimited with a '<tt>;</tt>' and go until the end of
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]463 line.</li>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]464
465 <li>Unnamed temporaries are created when the result of a computation is not
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]466 assigned to a named value.</li>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]467
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]468 <li>Unnamed temporaries are numbered sequentially</li>
469</ol>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]470
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]471<p>It also shows a convention that we follow in this document. When
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]472 demonstrating instructions, we will follow an instruction with a comment that
473 defines the type and name of value produced. Comments are shown in italic
474 text.</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]475
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]476</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]477
478<!-- *********************************************************************** -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]479<h2><a name="highlevel">High Level Structure</a></h2>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]480<!-- *********************************************************************** -->
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]481<div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]482<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]483<h3>
484 <a name="modulestructure">Module Structure</a>
485</h3>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]486
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]487<div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]488
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]489<p>LLVM programs are composed of "Module"s, each of which is a translation unit
490 of the input programs. Each module consists of functions, global variables,
491 and symbol table entries. Modules may be combined together with the LLVM
492 linker, which merges function (and global variable) definitions, resolves
493 forward declarations, and merges symbol table entries. Here is an example of
494 the "hello world" module:</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]495
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]496<pre class="doc_code">
Chris Lattner63e4ccb2010-08-17 17:13:42 +0000[diff] [blame]497<i>; Declare the string constant as a global constant.</i>&nbsp;
Nick Lewyckydb9cd762011-01-29 01:09:53 +0000[diff] [blame]498<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]499
Chris Lattner63e4ccb2010-08-17 17:13:42 +0000[diff] [blame]500<i>; External declaration of the puts function</i>&nbsp;
501<a href="#functionstructure">declare</a> i32 @puts(i8*) <i>; i32 (i8*)* </i>&nbsp;
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]502
503<i>; Definition of main function</i>
Chris Lattner63e4ccb2010-08-17 17:13:42 +0000[diff] [blame]504define i32 @main() { <i>; i32()* </i>&nbsp;
505 <i>; Convert [13 x i8]* to i8 *...</i>&nbsp;
506 %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]507
Chris Lattner63e4ccb2010-08-17 17:13:42 +0000[diff] [blame]508 <i>; Call puts function to write out the string to stdout.</i>&nbsp;
509 <a href="#i_call">call</a> i32 @puts(i8* %cast210) <i>; i32</i>&nbsp;
510 <a href="#i_ret">ret</a> i32 0&nbsp;
511}
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]512
513<i>; Named metadata</i>
514!1 = metadata !{i32 41}
515!foo = !{!1, null}
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]516</pre>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]517
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]518<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]519 "<tt>.LC0</tt>", an external declaration of the "<tt>puts</tt>" function,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]520 a <a href="#functionstructure">function definition</a> for
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]521 "<tt>main</tt>" and <a href="#namedmetadatastructure">named metadata</a>
522 "<tt>foo"</tt>.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]523
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]524<p>In general, a module is made up of a list of global values, where both
525 functions and global variables are global values. Global values are
526 represented by a pointer to a memory location (in this case, a pointer to an
527 array of char, and a pointer to a function), and have one of the
528 following <a href="#linkage">linkage types</a>.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]529
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]530</div>
531
532<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]533<h3>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]534 <a name="linkage">Linkage Types</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]535</h3>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]536
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]537<div>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]538
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]539<p>All Global Variables and Functions have one of the following types of
540 linkage:</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]541
542<dl>
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]543 <dt><tt><b><a name="linkage_private">private</a></b></tt></dt>
Bill Wendling5e721d72010-07-01 21:55:59 +0000[diff] [blame]544 <dd>Global values with "<tt>private</tt>" linkage are only directly accessible
545 by objects in the current module. In particular, linking code into a
546 module with an private global value may cause the private to be renamed as
547 necessary to avoid collisions. Because the symbol is private to the
548 module, all references can be updated. This doesn't show up in any symbol
549 table in the object file.</dd>
Rafael Espindolabb46f522009-01-15 20:18:42 +0000[diff] [blame]550
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]551 <dt><tt><b><a name="linkage_linker_private">linker_private</a></b></tt></dt>
Bill Wendling5e721d72010-07-01 21:55:59 +0000[diff] [blame]552 <dd>Similar to <tt>private</tt>, but the symbol is passed through the
553 assembler and evaluated by the linker. Unlike normal strong symbols, they
554 are removed by the linker from the final linked image (executable or
555 dynamic library).</dd>
556
557 <dt><tt><b><a name="linkage_linker_private_weak">linker_private_weak</a></b></tt></dt>
558 <dd>Similar to "<tt>linker_private</tt>", but the symbol is weak. Note that
559 <tt>linker_private_weak</tt> symbols are subject to coalescing by the
560 linker. The symbols are removed by the linker from the final linked image
561 (executable or dynamic library).</dd>
Bill Wendling3d10a5a2009-07-20 01:03:30 +0000[diff] [blame]562
Bill Wendling55ae5152010-08-20 22:05:50 +0000[diff] [blame]563 <dt><tt><b><a name="linkage_linker_private_weak_def_auto">linker_private_weak_def_auto</a></b></tt></dt>
564 <dd>Similar to "<tt>linker_private_weak</tt>", but it's known that the address
565 of the object is not taken. For instance, functions that had an inline
566 definition, but the compiler decided not to inline it. Note,
567 unlike <tt>linker_private</tt> and <tt>linker_private_weak</tt>,
568 <tt>linker_private_weak_def_auto</tt> may have only <tt>default</tt>
569 visibility. The symbols are removed by the linker from the final linked
570 image (executable or dynamic library).</dd>
571
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]572 <dt><tt><b><a name="linkage_internal">internal</a></b></tt></dt>
Bill Wendling07d31772010-06-29 22:34:52 +0000[diff] [blame]573 <dd>Similar to private, but the value shows as a local symbol
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]574 (<tt>STB_LOCAL</tt> in the case of ELF) in the object file. This
575 corresponds to the notion of the '<tt>static</tt>' keyword in C.</dd>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]576
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]577 <dt><tt><b><a name="linkage_available_externally">available_externally</a></b></tt></dt>
Chris Lattner266c7bb2009-04-13 05:44:34 +0000[diff] [blame]578 <dd>Globals with "<tt>available_externally</tt>" linkage are never emitted
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]579 into the object file corresponding to the LLVM module. They exist to
580 allow inlining and other optimizations to take place given knowledge of
581 the definition of the global, which is known to be somewhere outside the
582 module. Globals with <tt>available_externally</tt> linkage are allowed to
583 be discarded at will, and are otherwise the same as <tt>linkonce_odr</tt>.
584 This linkage type is only allowed on definitions, not declarations.</dd>
Chris Lattner266c7bb2009-04-13 05:44:34 +0000[diff] [blame]585
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]586 <dt><tt><b><a name="linkage_linkonce">linkonce</a></b></tt></dt>
Chris Lattner4887bd82007-01-14 06:51:48 +0000[diff] [blame]587 <dd>Globals with "<tt>linkonce</tt>" linkage are merged with other globals of
Chris Lattner873187c2010-01-09 19:15:14 +0000[diff] [blame]588 the same name when linkage occurs. This can be used to implement
589 some forms of inline functions, templates, or other code which must be
590 generated in each translation unit that uses it, but where the body may
591 be overridden with a more definitive definition later. Unreferenced
592 <tt>linkonce</tt> globals are allowed to be discarded. Note that
593 <tt>linkonce</tt> linkage does not actually allow the optimizer to
594 inline the body of this function into callers because it doesn't know if
595 this definition of the function is the definitive definition within the
596 program or whether it will be overridden by a stronger definition.
597 To enable inlining and other optimizations, use "<tt>linkonce_odr</tt>"
598 linkage.</dd>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]599
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]600 <dt><tt><b><a name="linkage_weak">weak</a></b></tt></dt>
Chris Lattner26d054d2009-08-05 05:21:07 +0000[diff] [blame]601 <dd>"<tt>weak</tt>" linkage has the same merging semantics as
602 <tt>linkonce</tt> linkage, except that unreferenced globals with
603 <tt>weak</tt> linkage may not be discarded. This is used for globals that
604 are declared "weak" in C source code.</dd>
605
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]606 <dt><tt><b><a name="linkage_common">common</a></b></tt></dt>
Chris Lattner26d054d2009-08-05 05:21:07 +0000[diff] [blame]607 <dd>"<tt>common</tt>" linkage is most similar to "<tt>weak</tt>" linkage, but
608 they are used for tentative definitions in C, such as "<tt>int X;</tt>" at
609 global scope.
610 Symbols with "<tt>common</tt>" linkage are merged in the same way as
611 <tt>weak symbols</tt>, and they may not be deleted if unreferenced.
Chris Lattnercd81f5d2009-08-05 05:41:44 +0000[diff] [blame]612 <tt>common</tt> symbols may not have an explicit section,
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]613 must have a zero initializer, and may not be marked '<a
Chris Lattnercd81f5d2009-08-05 05:41:44 +0000[diff] [blame]614 href="#globalvars"><tt>constant</tt></a>'. Functions and aliases may not
615 have common linkage.</dd>
Chris Lattner26d054d2009-08-05 05:21:07 +0000[diff] [blame]616
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_appending">appending</a></b></tt></dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]619 <dd>"<tt>appending</tt>" linkage may only be applied to global variables of
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]620 pointer to array type. When two global variables with appending linkage
621 are linked together, the two global arrays are appended together. This is
622 the LLVM, typesafe, equivalent of having the system linker append together
623 "sections" with identical names when .o files are linked.</dd>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]624
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]625 <dt><tt><b><a name="linkage_externweak">extern_weak</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]626 <dd>The semantics of this linkage follow the ELF object file model: the symbol
627 is weak until linked, if not linked, the symbol becomes null instead of
628 being an undefined reference.</dd>
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]629
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]630 <dt><tt><b><a name="linkage_linkonce_odr">linkonce_odr</a></b></tt></dt>
631 <dt><tt><b><a name="linkage_weak_odr">weak_odr</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]632 <dd>Some languages allow differing globals to be merged, such as two functions
633 with different semantics. Other languages, such as <tt>C++</tt>, ensure
Bill Wendling5e721d72010-07-01 21:55:59 +0000[diff] [blame]634 that only equivalent globals are ever merged (the "one definition rule"
635 &mdash; "ODR"). Such languages can use the <tt>linkonce_odr</tt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]636 and <tt>weak_odr</tt> linkage types to indicate that the global will only
637 be merged with equivalent globals. These linkage types are otherwise the
638 same as their non-<tt>odr</tt> versions.</dd>
Duncan Sands667d4b82009-03-07 15:45:40 +0000[diff] [blame]639
Bill Wendling5c3a9f72011-11-04 20:40:41 +0000[diff] [blame]640 <dt><tt><b><a name="linkage_external">external</a></b></tt></dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]641 <dd>If none of the above identifiers are used, the global is externally
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]642 visible, meaning that it participates in linkage and can be used to
643 resolve external symbol references.</dd>
Reid Spencerc8910842007-04-11 23:49:50 +0000[diff] [blame]644</dl>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]645
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]646<p>The next two types of linkage are targeted for Microsoft Windows platform
647 only. They are designed to support importing (exporting) symbols from (to)
648 DLLs (Dynamic Link Libraries).</p>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]649
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]650<dl>
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]651 <dt><tt><b><a name="linkage_dllimport">dllimport</a></b></tt></dt>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]652 <dd>"<tt>dllimport</tt>" linkage causes the compiler to reference a function
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]653 or variable via a global pointer to a pointer that is set up by the DLL
654 exporting the symbol. On Microsoft Windows targets, the pointer name is
655 formed by combining <code>__imp_</code> and the function or variable
656 name.</dd>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]657
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]658 <dt><tt><b><a name="linkage_dllexport">dllexport</a></b></tt></dt>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]659 <dd>"<tt>dllexport</tt>" linkage causes the compiler to provide a global
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]660 pointer to a pointer in a DLL, so that it can be referenced with the
661 <tt>dllimport</tt> attribute. On Microsoft Windows targets, the pointer
662 name is formed by combining <code>__imp_</code> and the function or
663 variable name.</dd>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]664</dl>
665
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]666<p>For example, since the "<tt>.LC0</tt>" variable is defined to be internal, if
667 another module defined a "<tt>.LC0</tt>" variable and was linked with this
668 one, one of the two would be renamed, preventing a collision. Since
669 "<tt>main</tt>" and "<tt>puts</tt>" are external (i.e., lacking any linkage
670 declarations), they are accessible outside of the current module.</p>
671
672<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]673 other than <tt>external</tt>, <tt>dllimport</tt>
674 or <tt>extern_weak</tt>.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]675
Duncan Sands667d4b82009-03-07 15:45:40 +0000[diff] [blame]676<p>Aliases can have only <tt>external</tt>, <tt>internal</tt>, <tt>weak</tt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]677 or <tt>weak_odr</tt> linkages.</p>
678
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]679</div>
680
681<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]682<h3>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]683 <a name="callingconv">Calling Conventions</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]684</h3>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]685
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]686<div>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]687
688<p>LLVM <a href="#functionstructure">functions</a>, <a href="#i_call">calls</a>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]689 and <a href="#i_invoke">invokes</a> can all have an optional calling
690 convention specified for the call. The calling convention of any pair of
691 dynamic caller/callee must match, or the behavior of the program is
692 undefined. The following calling conventions are supported by LLVM, and more
693 may be added in the future:</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]694
695<dl>
696 <dt><b>"<tt>ccc</tt>" - The C calling convention</b>:</dt>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]697 <dd>This calling convention (the default if no other calling convention is
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]698 specified) matches the target C calling conventions. This calling
699 convention supports varargs function calls and tolerates some mismatch in
700 the declared prototype and implemented declaration of the function (as
701 does normal C).</dd>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]702
703 <dt><b>"<tt>fastcc</tt>" - The fast calling convention</b>:</dt>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]704 <dd>This calling convention attempts to make calls as fast as possible
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]705 (e.g. by passing things in registers). This calling convention allows the
706 target to use whatever tricks it wants to produce fast code for the
707 target, without having to conform to an externally specified ABI
Jeffrey Yasskin95fa80a2010-01-09 19:44:16 +0000[diff] [blame]708 (Application Binary Interface).
709 <a href="CodeGenerator.html#tailcallopt">Tail calls can only be optimized
Chris Lattner29689432010-03-11 00:22:57 +0000[diff] [blame]710 when this or the GHC convention is used.</a> This calling convention
711 does not support varargs and requires the prototype of all callees to
712 exactly match the prototype of the function definition.</dd>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]713
714 <dt><b>"<tt>coldcc</tt>" - The cold calling convention</b>:</dt>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]715 <dd>This calling convention attempts to make code in the caller as efficient
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]716 as possible under the assumption that the call is not commonly executed.
717 As such, these calls often preserve all registers so that the call does
718 not break any live ranges in the caller side. This calling convention
719 does not support varargs and requires the prototype of all callees to
720 exactly match the prototype of the function definition.</dd>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]721
Chris Lattner29689432010-03-11 00:22:57 +0000[diff] [blame]722 <dt><b>"<tt>cc <em>10</em></tt>" - GHC convention</b>:</dt>
723 <dd>This calling convention has been implemented specifically for use by the
724 <a href="http://www.haskell.org/ghc">Glasgow Haskell Compiler (GHC)</a>.
725 It passes everything in registers, going to extremes to achieve this by
726 disabling callee save registers. This calling convention should not be
727 used lightly but only for specific situations such as an alternative to
728 the <em>register pinning</em> performance technique often used when
729 implementing functional programming languages.At the moment only X86
730 supports this convention and it has the following limitations:
731 <ul>
732 <li>On <em>X86-32</em> only supports up to 4 bit type parameters. No
733 floating point types are supported.</li>
734 <li>On <em>X86-64</em> only supports up to 10 bit type parameters and
735 6 floating point parameters.</li>
736 </ul>
737 This calling convention supports
738 <a href="CodeGenerator.html#tailcallopt">tail call optimization</a> but
739 requires both the caller and callee are using it.
740 </dd>
741
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame]742 <dt><b>"<tt>cc &lt;<em>n</em>&gt;</tt>" - Numbered convention</b>:</dt>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]743 <dd>Any calling convention may be specified by number, allowing
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]744 target-specific calling conventions to be used. Target specific calling
745 conventions start at 64.</dd>
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame]746</dl>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]747
748<p>More calling conventions can be added/defined on an as-needed basis, to
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]749 support Pascal conventions or any other well-known target-independent
750 convention.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]751
752</div>
753
754<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]755<h3>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]756 <a name="visibility">Visibility Styles</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]757</h3>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]758
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]759<div>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]760
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]761<p>All Global Variables and Functions have one of the following visibility
762 styles:</p>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]763
764<dl>
765 <dt><b>"<tt>default</tt>" - Default style</b>:</dt>
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]766 <dd>On targets that use the ELF object file format, default visibility means
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]767 that the declaration is visible to other modules and, in shared libraries,
768 means that the declared entity may be overridden. On Darwin, default
769 visibility means that the declaration is visible to other modules. Default
770 visibility corresponds to "external linkage" in the language.</dd>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]771
772 <dt><b>"<tt>hidden</tt>" - Hidden style</b>:</dt>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]773 <dd>Two declarations of an object with hidden visibility refer to the same
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]774 object if they are in the same shared object. Usually, hidden visibility
775 indicates that the symbol will not be placed into the dynamic symbol
776 table, so no other module (executable or shared library) can reference it
777 directly.</dd>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]778
Anton Korobeynikov6f9896f2007-04-29 18:35:00 +0000[diff] [blame]779 <dt><b>"<tt>protected</tt>" - Protected style</b>:</dt>
Anton Korobeynikov6f9896f2007-04-29 18:35:00 +0000[diff] [blame]780 <dd>On ELF, protected visibility indicates that the symbol will be placed in
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]781 the dynamic symbol table, but that references within the defining module
782 will bind to the local symbol. That is, the symbol cannot be overridden by
783 another module.</dd>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]784</dl>
785
786</div>
787
788<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]789<h3>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]790 <a name="namedtypes">Named Types</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]791</h3>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]792
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]793<div>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]794
795<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]796 it easier to read the IR and make the IR more condensed (particularly when
797 recursive types are involved). An example of a name specification is:</p>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]798
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]799<pre class="doc_code">
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]800%mytype = type { %mytype*, i32 }
801</pre>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]802
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]803<p>You may give a name to any <a href="#typesystem">type</a> except
Chris Lattnerdc65f222010-08-17 23:26:04 +0000[diff] [blame]804 "<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]805 is expected with the syntax "%mytype".</p>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]806
807<p>Note that type names are aliases for the structural type that they indicate,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]808 and that you can therefore specify multiple names for the same type. This
809 often leads to confusing behavior when dumping out a .ll file. Since LLVM IR
810 uses structural typing, the name is not part of the type. When printing out
811 LLVM IR, the printer will pick <em>one name</em> to render all types of a
812 particular shape. This means that if you have code where two different
813 source types end up having the same LLVM type, that the dumper will sometimes
814 print the "wrong" or unexpected type. This is an important design point and
815 isn't going to change.</p>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]816
817</div>
818
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]819<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]820<h3>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]821 <a name="globalvars">Global Variables</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]822</h3>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]823
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]824<div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]825
Chris Lattner3689a342005-02-12 19:30:21 +0000[diff] [blame]826<p>Global variables define regions of memory allocated at compilation time
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]827 instead of run-time. Global variables may optionally be initialized, may
828 have an explicit section to be placed in, and may have an optional explicit
829 alignment specified. A variable may be defined as "thread_local", which
830 means that it will not be shared by threads (each thread will have a
831 separated copy of the variable). A variable may be defined as a global
832 "constant," which indicates that the contents of the variable
833 will <b>never</b> be modified (enabling better optimization, allowing the
834 global data to be placed in the read-only section of an executable, etc).
835 Note that variables that need runtime initialization cannot be marked
836 "constant" as there is a store to the variable.</p>
Chris Lattner3689a342005-02-12 19:30:21 +0000[diff] [blame]837
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]838<p>LLVM explicitly allows <em>declarations</em> of global variables to be marked
839 constant, even if the final definition of the global is not. This capability
840 can be used to enable slightly better optimization of the program, but
841 requires the language definition to guarantee that optimizations based on the
842 'constantness' are valid for the translation units that do not include the
843 definition.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]844
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]845<p>As SSA values, global variables define pointer values that are in scope
846 (i.e. they dominate) all basic blocks in the program. Global variables
847 always define a pointer to their "content" type because they describe a
848 region of memory, and all memory objects in LLVM are accessed through
849 pointers.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]850
Rafael Espindolabea46262011-01-08 16:42:36 +0000[diff] [blame]851<p>Global variables can be marked with <tt>unnamed_addr</tt> which indicates
852 that the address is not significant, only the content. Constants marked
Rafael Espindolaa5eaa862011-01-15 08:20:57 +0000[diff] [blame]853 like this can be merged with other constants if they have the same
854 initializer. Note that a constant with significant address <em>can</em>
855 be merged with a <tt>unnamed_addr</tt> constant, the result being a
856 constant whose address is significant.</p>
Rafael Espindolabea46262011-01-08 16:42:36 +0000[diff] [blame]857
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]858<p>A global variable may be declared to reside in a target-specific numbered
859 address space. For targets that support them, address spaces may affect how
860 optimizations are performed and/or what target instructions are used to
861 access the variable. The default address space is zero. The address space
862 qualifier must precede any other attributes.</p>
Christopher Lamb284d9922007-12-11 09:31:00 +0000[diff] [blame]863
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]864<p>LLVM allows an explicit section to be specified for globals. If the target
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]865 supports it, it will emit globals to the section specified.</p>
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]866
Chris Lattnerce99fa92010-04-28 00:13:42 +0000[diff] [blame]867<p>An explicit alignment may be specified for a global, which must be a power
868 of 2. If not present, or if the alignment is set to zero, the alignment of
869 the global is set by the target to whatever it feels convenient. If an
870 explicit alignment is specified, the global is forced to have exactly that
Chris Lattner2d4b8ee2010-04-28 00:31:12 +0000[diff] [blame]871 alignment. Targets and optimizers are not allowed to over-align the global
872 if the global has an assigned section. In this case, the extra alignment
873 could be observable: for example, code could assume that the globals are
874 densely packed in their section and try to iterate over them as an array,
875 alignment padding would break this iteration.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]876
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]877<p>For example, the following defines a global in a numbered address space with
878 an initializer, section, and alignment:</p>
Chris Lattner68027ea2007-01-14 00:27:09 +0000[diff] [blame]879
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]880<pre class="doc_code">
Dan Gohman398873c2009-01-11 00:40:00 +0000[diff] [blame]881@G = addrspace(5) constant float 1.0, section "foo", align 4
Chris Lattner68027ea2007-01-14 00:27:09 +0000[diff] [blame]882</pre>
883
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]884</div>
885
886
887<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]888<h3>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]889 <a name="functionstructure">Functions</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]890</h3>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]891
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]892<div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]893
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]894<p>LLVM function definitions consist of the "<tt>define</tt>" keyword, an
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]895 optional <a href="#linkage">linkage type</a>, an optional
896 <a href="#visibility">visibility style</a>, an optional
Rafael Espindolabea46262011-01-08 16:42:36 +0000[diff] [blame]897 <a href="#callingconv">calling convention</a>,
898 an optional <tt>unnamed_addr</tt> attribute, a return type, an optional
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]899 <a href="#paramattrs">parameter attribute</a> for the return type, a function
900 name, a (possibly empty) argument list (each with optional
901 <a href="#paramattrs">parameter attributes</a>), optional
902 <a href="#fnattrs">function attributes</a>, an optional section, an optional
903 alignment, an optional <a href="#gc">garbage collector name</a>, an opening
904 curly brace, a list of basic blocks, and a closing curly brace.</p>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]905
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]906<p>LLVM function declarations consist of the "<tt>declare</tt>" keyword, an
907 optional <a href="#linkage">linkage type</a>, an optional
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]908 <a href="#visibility">visibility style</a>, an optional
Rafael Espindolabea46262011-01-08 16:42:36 +0000[diff] [blame]909 <a href="#callingconv">calling convention</a>,
910 an optional <tt>unnamed_addr</tt> attribute, a return type, an optional
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]911 <a href="#paramattrs">parameter attribute</a> for the return type, a function
912 name, a possibly empty list of arguments, an optional alignment, and an
913 optional <a href="#gc">garbage collector name</a>.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]914
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]915<p>A function definition contains a list of basic blocks, forming the CFG
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]916 (Control Flow Graph) for the function. Each basic block may optionally start
917 with a label (giving the basic block a symbol table entry), contains a list
918 of instructions, and ends with a <a href="#terminators">terminator</a>
919 instruction (such as a branch or function return).</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]920
Chris Lattner4a3c9012007-06-08 16:52:14 +0000[diff] [blame]921<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]922 executed on entrance to the function, and it is not allowed to have
923 predecessor basic blocks (i.e. there can not be any branches to the entry
924 block of a function). Because the block can have no predecessors, it also
925 cannot have any <a href="#i_phi">PHI nodes</a>.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]926
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]927<p>LLVM allows an explicit section to be specified for functions. If the target
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]928 supports it, it will emit functions to the section specified.</p>
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]929
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]930<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]931 the alignment is set to zero, the alignment of the function is set by the
932 target to whatever it feels convenient. If an explicit alignment is
933 specified, the function is forced to have at least that much alignment. All
934 alignments must be a power of 2.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]935
Rafael Espindolabea46262011-01-08 16:42:36 +0000[diff] [blame]936<p>If the <tt>unnamed_addr</tt> attribute is given, the address is know to not
Bill Wendling5c3a9f72011-11-04 20:40:41 +0000[diff] [blame]937 be significant and two identical functions can be merged.</p>
Rafael Espindolabea46262011-01-08 16:42:36 +0000[diff] [blame]938
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]939<h5>Syntax:</h5>
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]940<pre class="doc_code">
Chris Lattner50ad45c2008-10-13 16:55:18 +0000[diff] [blame]941define [<a href="#linkage">linkage</a>] [<a href="#visibility">visibility</a>]
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]942 [<a href="#callingconv">cconv</a>] [<a href="#paramattrs">ret attrs</a>]
943 &lt;ResultType&gt; @&lt;FunctionName&gt; ([argument list])
944 [<a href="#fnattrs">fn Attrs</a>] [section "name"] [align N]
945 [<a href="#gc">gc</a>] { ... }
946</pre>
Devang Patel307e8ab2008-10-07 17:48:33 +0000[diff] [blame]947
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]948</div>
949
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]950<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]951<h3>
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]952 <a name="aliasstructure">Aliases</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]953</h3>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]954
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]955<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]956
957<p>Aliases act as "second name" for the aliasee value (which can be either
958 function, global variable, another alias or bitcast of global value). Aliases
959 may have an optional <a href="#linkage">linkage type</a>, and an
960 optional <a href="#visibility">visibility style</a>.</p>
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]961
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]962<h5>Syntax:</h5>
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]963<pre class="doc_code">
Duncan Sands0b23ac12008-09-12 20:48:21 +0000[diff] [blame]964@&lt;Name&gt; = alias [Linkage] [Visibility] &lt;AliaseeTy&gt; @&lt;Aliasee&gt;
Bill Wendlingaac388b2007-05-29 09:42:13 +0000[diff] [blame]965</pre>
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]966
967</div>
968
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]969<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]970<h3>
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]971 <a name="namedmetadatastructure">Named Metadata</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]972</h3>
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]973
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]974<div>
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]975
Chris Lattnere6a5ddd2010-01-15 21:50:19 +0000[diff] [blame]976<p>Named metadata is a collection of metadata. <a href="#metadata">Metadata
Dan Gohman872814a2010-07-21 18:54:18 +0000[diff] [blame]977 nodes</a> (but not metadata strings) are the only valid operands for
Chris Lattnere6a5ddd2010-01-15 21:50:19 +0000[diff] [blame]978 a named metadata.</p>
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]979
980<h5>Syntax:</h5>
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]981<pre class="doc_code">
Dan Gohman872814a2010-07-21 18:54:18 +0000[diff] [blame]982; Some unnamed metadata nodes, which are referenced by the named metadata.
983!0 = metadata !{metadata !"zero"}
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]984!1 = metadata !{metadata !"one"}
Dan Gohman872814a2010-07-21 18:54:18 +0000[diff] [blame]985!2 = metadata !{metadata !"two"}
Dan Gohman1005bc52010-07-13 19:48:13 +0000[diff] [blame]986; A named metadata.
Dan Gohman872814a2010-07-21 18:54:18 +0000[diff] [blame]987!name = !{!0, !1, !2}
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]988</pre>
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]989
990</div>
991
992<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]993<h3>
994 <a name="paramattrs">Parameter Attributes</a>
995</h3>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]996
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]997<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]998
999<p>The return type and each parameter of a function type may have a set of
1000 <i>parameter attributes</i> associated with them. Parameter attributes are
1001 used to communicate additional information about the result or parameters of
1002 a function. Parameter attributes are considered to be part of the function,
1003 not of the function type, so functions with different parameter attributes
1004 can have the same function type.</p>
1005
1006<p>Parameter attributes are simple keywords that follow the type specified. If
1007 multiple parameter attributes are needed, they are space separated. For
1008 example:</p>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1009
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]1010<pre class="doc_code">
Nick Lewyckyb6a7d252009-02-15 23:06:14 +0000[diff] [blame]1011declare i32 @printf(i8* noalias nocapture, ...)
Chris Lattner66d922c2008-10-04 18:33:34 +0000[diff] [blame]1012declare i32 @atoi(i8 zeroext)
1013declare signext i8 @returns_signed_char()
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1014</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1015
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1016<p>Note that any attributes for the function result (<tt>nounwind</tt>,
1017 <tt>readonly</tt>) come immediately after the argument list.</p>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1018
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1019<p>Currently, only the following parameter attributes are defined:</p>
Chris Lattner47507de2008-01-11 06:20:47 +0000[diff] [blame]1020
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1021<dl>
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1022 <dt><tt><b>zeroext</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1023 <dd>This indicates to the code generator that the parameter or return value
Cameron Zwarichebe81732011-03-16 22:20:18 +0000[diff] [blame]1024 should be zero-extended to the extent required by the target's ABI (which
1025 is usually 32-bits, but is 8-bits for a i1 on x86-64) by the caller (for a
1026 parameter) or the callee (for a return value).</dd>
Chris Lattner47507de2008-01-11 06:20:47 +0000[diff] [blame]1027
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1028 <dt><tt><b>signext</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1029 <dd>This indicates to the code generator that the parameter or return value
Cameron Zwarich9e69ff92011-03-17 14:21:58 +0000[diff] [blame]1030 should be sign-extended to the extent required by the target's ABI (which
1031 is usually 32-bits) by the caller (for a parameter) or the callee (for a
1032 return value).</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>inreg</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1035 <dd>This indicates that this parameter or return value should be treated in a
1036 special target-dependent fashion during while emitting code for a function
1037 call or return (usually, by putting it in a register as opposed to memory,
1038 though some targets use it to distinguish between two different kinds of
1039 registers). Use of this attribute is target-specific.</dd>
Chris Lattner47507de2008-01-11 06:20:47 +0000[diff] [blame]1040
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1041 <dt><tt><b><a name="byval">byval</a></b></tt></dt>
Chris Lattnera6fd81d2010-11-20 23:49:06 +0000[diff] [blame]1042 <dd><p>This indicates that the pointer parameter should really be passed by
1043 value to the function. The attribute implies that a hidden copy of the
1044 pointee
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1045 is made between the caller and the callee, so the callee is unable to
1046 modify the value in the callee. This attribute is only valid on LLVM
1047 pointer arguments. It is generally used to pass structs and arrays by
1048 value, but is also valid on pointers to scalars. The copy is considered
1049 to belong to the caller not the callee (for example,
1050 <tt><a href="#readonly">readonly</a></tt> functions should not write to
1051 <tt>byval</tt> parameters). This is not a valid attribute for return
Chris Lattnera6fd81d2010-11-20 23:49:06 +0000[diff] [blame]1052 values.</p>
1053
1054 <p>The byval attribute also supports specifying an alignment with
1055 the align attribute. It indicates the alignment of the stack slot to
1056 form and the known alignment of the pointer specified to the call site. If
1057 the alignment is not specified, then the code generator makes a
1058 target-specific assumption.</p></dd>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1059
Dan Gohmanff235352010-07-02 23:18:08 +0000[diff] [blame]1060 <dt><tt><b><a name="sret">sret</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1061 <dd>This indicates that the pointer parameter specifies the address of a
1062 structure that is the return value of the function in the source program.
1063 This pointer must be guaranteed by the caller to be valid: loads and
1064 stores to the structure may be assumed by the callee to not to trap. This
1065 may only be applied to the first parameter. This is not a valid attribute
1066 for return values. </dd>
1067
Dan Gohmanff235352010-07-02 23:18:08 +0000[diff] [blame]1068 <dt><tt><b><a name="noalias">noalias</a></b></tt></dt>
Dan Gohman1e109622010-07-02 18:41:32 +0000[diff] [blame]1069 <dd>This indicates that pointer values
1070 <a href="#pointeraliasing"><i>based</i></a> on the argument or return
Dan Gohmanefca7f92010-07-02 23:46:54 +0000[diff] [blame]1071 value do not alias pointer values which are not <i>based</i> on it,
1072 ignoring certain "irrelevant" dependencies.
1073 For a call to the parent function, dependencies between memory
1074 references from before or after the call and from those during the call
1075 are "irrelevant" to the <tt>noalias</tt> keyword for the arguments and
1076 return value used in that call.
Dan Gohman1e109622010-07-02 18:41:32 +0000[diff] [blame]1077 The caller shares the responsibility with the callee for ensuring that
1078 these requirements are met.
1079 For further details, please see the discussion of the NoAlias response in
Dan Gohmanff70fe42010-07-06 15:26:33 +0000[diff] [blame]1080 <a href="AliasAnalysis.html#MustMayNo">alias analysis</a>.<br>
1081<br>
John McCall191d4ee2010-07-06 21:07:14 +0000[diff] [blame]1082 Note that this definition of <tt>noalias</tt> is intentionally
1083 similar to the definition of <tt>restrict</tt> in C99 for function
Chris Lattner211244a2010-07-06 20:51:35 +0000[diff] [blame]1084 arguments, though it is slightly weaker.
Dan Gohmanff70fe42010-07-06 15:26:33 +0000[diff] [blame]1085<br>
1086 For function return values, C99's <tt>restrict</tt> is not meaningful,
1087 while LLVM's <tt>noalias</tt> is.
1088 </dd>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1089
Dan Gohmanff235352010-07-02 23:18:08 +0000[diff] [blame]1090 <dt><tt><b><a name="nocapture">nocapture</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1091 <dd>This indicates that the callee does not make any copies of the pointer
1092 that outlive the callee itself. This is not a valid attribute for return
1093 values.</dd>
1094
Dan Gohmanff235352010-07-02 23:18:08 +0000[diff] [blame]1095 <dt><tt><b><a name="nest">nest</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1096 <dd>This indicates that the pointer parameter can be excised using the
1097 <a href="#int_trampoline">trampoline intrinsics</a>. This is not a valid
1098 attribute for return values.</dd>
1099</dl>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1100
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1101</div>
1102
1103<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1104<h3>
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]1105 <a name="gc">Garbage Collector Names</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1106</h3>
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]1107
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1108<div>
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]1109
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1110<p>Each function may specify a garbage collector name, which is simply a
1111 string:</p>
1112
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]1113<pre class="doc_code">
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1114define void @f() gc "name" { ... }
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1115</pre>
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]1116
1117<p>The compiler declares the supported values of <i>name</i>. Specifying a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1118 collector which will cause the compiler to alter its output in order to
1119 support the named garbage collection algorithm.</p>
1120
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]1121</div>
1122
1123<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1124<h3>
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1125 <a name="fnattrs">Function Attributes</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1126</h3>
Devang Patelf8b94812008-09-04 23:05:13 +0000[diff] [blame]1127
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1128<div>
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1129
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1130<p>Function attributes are set to communicate additional information about a
1131 function. Function attributes are considered to be part of the function, not
1132 of the function type, so functions with different parameter attributes can
1133 have the same function type.</p>
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1134
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1135<p>Function attributes are simple keywords that follow the type specified. If
1136 multiple attributes are needed, they are space separated. For example:</p>
Devang Patelf8b94812008-09-04 23:05:13 +0000[diff] [blame]1137
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]1138<pre class="doc_code">
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1139define void @f() noinline { ... }
1140define void @f() alwaysinline { ... }
1141define void @f() alwaysinline optsize { ... }
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1142define void @f() optsize { ... }
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1143</pre>
Devang Patelf8b94812008-09-04 23:05:13 +0000[diff] [blame]1144
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1145<dl>
Charles Davis1e063d12010-02-12 00:31:15 +0000[diff] [blame]1146 <dt><tt><b>alignstack(&lt;<em>n</em>&gt;)</b></tt></dt>
1147 <dd>This attribute indicates that, when emitting the prologue and epilogue,
1148 the backend should forcibly align the stack pointer. Specify the
1149 desired alignment, which must be a power of two, in parentheses.
1150
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1151 <dt><tt><b>alwaysinline</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1152 <dd>This attribute indicates that the inliner should attempt to inline this
1153 function into callers whenever possible, ignoring any active inlining size
1154 threshold for this caller.</dd>
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1155
Dan Gohman129bd562011-06-16 16:03:13 +0000[diff] [blame]1156 <dt><tt><b>nonlazybind</b></tt></dt>
1157 <dd>This attribute suppresses lazy symbol binding for the function. This
1158 may make calls to the function faster, at the cost of extra program
1159 startup time if the function is not called during program startup.</dd>
1160
Jakob Stoklund Olesen570a4a52010-02-06 01:16:28 +0000[diff] [blame]1161 <dt><tt><b>inlinehint</b></tt></dt>
1162 <dd>This attribute indicates that the source code contained a hint that inlining
1163 this function is desirable (such as the "inline" keyword in C/C++). It
1164 is just a hint; it imposes no requirements on the inliner.</dd>
1165
Nick Lewycky76ec37a2010-07-06 18:24:09 +0000[diff] [blame]1166 <dt><tt><b>naked</b></tt></dt>
1167 <dd>This attribute disables prologue / epilogue emission for the function.
1168 This can have very system-specific consequences.</dd>
1169
1170 <dt><tt><b>noimplicitfloat</b></tt></dt>
1171 <dd>This attributes disables implicit floating point instructions.</dd>
1172
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1173 <dt><tt><b>noinline</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1174 <dd>This attribute indicates that the inliner should never inline this
1175 function in any situation. This attribute may not be used together with
1176 the <tt>alwaysinline</tt> attribute.</dd>
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1177
Nick Lewycky76ec37a2010-07-06 18:24:09 +0000[diff] [blame]1178 <dt><tt><b>noredzone</b></tt></dt>
1179 <dd>This attribute indicates that the code generator should not use a red
1180 zone, even if the target-specific ABI normally permits it.</dd>
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1181
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1182 <dt><tt><b>noreturn</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1183 <dd>This function attribute indicates that the function never returns
1184 normally. This produces undefined behavior at runtime if the function
1185 ever does dynamically return.</dd>
Bill Wendling31359ba2008-11-13 01:02:51 +0000[diff] [blame]1186
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1187 <dt><tt><b>nounwind</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1188 <dd>This function attribute indicates that the function never returns with an
1189 unwind or exceptional control flow. If the function does unwind, its
1190 runtime behavior is undefined.</dd>
Bill Wendlingfbaa7ed2008-11-26 19:07:40 +0000[diff] [blame]1191
Nick Lewycky76ec37a2010-07-06 18:24:09 +0000[diff] [blame]1192 <dt><tt><b>optsize</b></tt></dt>
1193 <dd>This attribute suggests that optimization passes and code generator passes
1194 make choices that keep the code size of this function low, and otherwise
1195 do optimizations specifically to reduce code size.</dd>
1196
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1197 <dt><tt><b>readnone</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1198 <dd>This attribute indicates that the function computes its result (or decides
1199 to unwind an exception) based strictly on its arguments, without
1200 dereferencing any pointer arguments or otherwise accessing any mutable
1201 state (e.g. memory, control registers, etc) visible to caller functions.
1202 It does not write through any pointer arguments
1203 (including <tt><a href="#byval">byval</a></tt> arguments) and never
1204 changes any state visible to callers. This means that it cannot unwind
1205 exceptions by calling the <tt>C++</tt> exception throwing methods, but
1206 could use the <tt>unwind</tt> instruction.</dd>
Devang Patel5d96fda2009-06-12 19:45:19 +0000[diff] [blame]1207
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1208 <dt><tt><b><a name="readonly">readonly</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1209 <dd>This attribute indicates that the function does not write through any
1210 pointer arguments (including <tt><a href="#byval">byval</a></tt>
1211 arguments) or otherwise modify any state (e.g. memory, control registers,
1212 etc) visible to caller functions. It may dereference pointer arguments
1213 and read state that may be set in the caller. A readonly function always
1214 returns the same value (or unwinds an exception identically) when called
1215 with the same set of arguments and global state. It cannot unwind an
1216 exception by calling the <tt>C++</tt> exception throwing methods, but may
1217 use the <tt>unwind</tt> instruction.</dd>
Anton Korobeynikovc5ec8a72009-07-17 18:07:26 +0000[diff] [blame]1218
Bill Wendling9bd5d042011-12-05 21:27:54 +0000[diff] [blame]1219 <dt><tt><b><a name="returns_twice">returns_twice</a></b></tt></dt>
1220 <dd>This attribute indicates that this function can return twice. The
1221 C <code>setjmp</code> is an example of such a function. The compiler
1222 disables some optimizations (like tail calls) in the caller of these
1223 functions.</dd>
1224
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1225 <dt><tt><b><a name="ssp">ssp</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1226 <dd>This attribute indicates that the function should emit a stack smashing
1227 protector. It is in the form of a "canary"&mdash;a random value placed on
1228 the stack before the local variables that's checked upon return from the
1229 function to see if it has been overwritten. A heuristic is used to
1230 determine if a function needs stack protectors or not.<br>
1231<br>
1232 If a function that has an <tt>ssp</tt> attribute is inlined into a
1233 function that doesn't have an <tt>ssp</tt> attribute, then the resulting
1234 function will have an <tt>ssp</tt> attribute.</dd>
1235
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1236 <dt><tt><b>sspreq</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1237 <dd>This attribute indicates that the function should <em>always</em> emit a
1238 stack smashing protector. This overrides
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1239 the <tt><a href="#ssp">ssp</a></tt> function attribute.<br>
1240<br>
1241 If a function that has an <tt>sspreq</tt> attribute is inlined into a
1242 function that doesn't have an <tt>sspreq</tt> attribute or which has
1243 an <tt>ssp</tt> attribute, then the resulting function will have
1244 an <tt>sspreq</tt> attribute.</dd>
Rafael Espindolafbff0ec2011-07-25 15:27:59 +0000[diff] [blame]1245
1246 <dt><tt><b><a name="uwtable">uwtable</a></b></tt></dt>
1247 <dd>This attribute indicates that the ABI being targeted requires that
1248 an unwind table entry be produce for this function even if we can
1249 show that no exceptions passes by it. This is normally the case for
1250 the ELF x86-64 abi, but it can be disabled for some compilation
1251 units.</dd>
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1252</dl>
1253
Devang Patelf8b94812008-09-04 23:05:13 +0000[diff] [blame]1254</div>
1255
1256<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1257<h3>
Chris Lattner1eeeb0c2006-04-08 04:40:53 +0000[diff] [blame]1258 <a name="moduleasm">Module-Level Inline Assembly</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1259</h3>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1260
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1261<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1262
1263<p>Modules may contain "module-level inline asm" blocks, which corresponds to
1264 the GCC "file scope inline asm" blocks. These blocks are internally
1265 concatenated by LLVM and treated as a single unit, but may be separated in
1266 the <tt>.ll</tt> file if desired. The syntax is very simple:</p>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1267
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]1268<pre class="doc_code">
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1269module asm "inline asm code goes here"
1270module asm "more can go here"
1271</pre>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1272
1273<p>The strings can contain any character by escaping non-printable characters.
1274 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]1275 for the number.</p>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1276
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1277<p>The inline asm code is simply printed to the machine code .s file when
1278 assembly code is generated.</p>
1279
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1280</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1281
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1282<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1283<h3>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1284 <a name="datalayout">Data Layout</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1285</h3>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1286
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1287<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1288
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1289<p>A module may specify a target specific data layout string that specifies how
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1290 data is to be laid out in memory. The syntax for the data layout is
1291 simply:</p>
1292
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]1293<pre class="doc_code">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1294target datalayout = "<i>layout specification</i>"
1295</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1296
1297<p>The <i>layout specification</i> consists of a list of specifications
1298 separated by the minus sign character ('-'). Each specification starts with
1299 a letter and may include other information after the letter to define some
1300 aspect of the data layout. The specifications accepted are as follows:</p>
1301
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1302<dl>
1303 <dt><tt>E</tt></dt>
1304 <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]1305 bits with the most significance have the lowest address location.</dd>
1306
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1307 <dt><tt>e</tt></dt>
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]1308 <dd>Specifies that the target lays out data in little-endian form. That is,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1309 the bits with the least significance have the lowest address
1310 location.</dd>
1311
Lang Hamesbb5b3f32011-10-10 23:42:08 +0000[diff] [blame]1312 <dt><tt>S<i>size</i></tt></dt>
1313 <dd>Specifies the natural alignment of the stack in bits. Alignment promotion
1314 of stack variables is limited to the natural stack alignment to avoid
1315 dynamic stack realignment. The stack alignment must be a multiple of
Lang Hames5f119a62011-10-11 17:50:14 +0000[diff] [blame]1316 8-bits. If omitted, the natural stack alignment defaults to "unspecified",
1317 which does not prevent any alignment promotions.</dd>
Lang Hamesbb5b3f32011-10-10 23:42:08 +0000[diff] [blame]1318
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1319 <dt><tt>p:<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]1320 <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]1321 <i>preferred</i> alignments. All sizes are in bits. Specifying
1322 the <i>pref</i> alignment is optional. If omitted, the
1323 preceding <tt>:</tt> should be omitted too.</dd>
1324
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1325 <dt><tt>i<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1326 <dd>This specifies the alignment for an integer type of a given bit
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1327 <i>size</i>. The value of <i>size</i> must be in the range [1,2^23).</dd>
1328
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1329 <dt><tt>v<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]1330 <dd>This specifies the alignment for a vector type of a given bit
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1331 <i>size</i>.</dd>
1332
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1333 <dt><tt>f<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]1334 <dd>This specifies the alignment for a floating point type of a given bit
Dale Johannesen9d8d2212010-05-28 18:54:47 +0000[diff] [blame]1335 <i>size</i>. Only values of <i>size</i> that are supported by the target
1336 will work. 32 (float) and 64 (double) are supported on all targets;
1337 80 or 128 (different flavors of long double) are also supported on some
1338 targets.
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1339
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1340 <dt><tt>a<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1341 <dd>This specifies the alignment for an aggregate type of a given bit
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1342 <i>size</i>.</dd>
1343
Daniel Dunbar87bde0b2009-06-08 22:17:53 +0000[diff] [blame]1344 <dt><tt>s<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1345 <dd>This specifies the alignment for a stack object of a given bit
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1346 <i>size</i>.</dd>
Chris Lattnere82bdc42009-11-07 09:35:34 +0000[diff] [blame]1347
1348 <dt><tt>n<i>size1</i>:<i>size2</i>:<i>size3</i>...</tt></dt>
1349 <dd>This specifies a set of native integer widths for the target CPU
1350 in bits. For example, it might contain "n32" for 32-bit PowerPC,
1351 "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]1352 this set are considered to support most general arithmetic
Chris Lattnere82bdc42009-11-07 09:35:34 +0000[diff] [blame]1353 operations efficiently.</dd>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1354</dl>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1355
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1356<p>When constructing the data layout for a given target, LLVM starts with a
Dan Gohman1c70c002010-04-28 00:36:01 +0000[diff] [blame]1357 default set of specifications which are then (possibly) overridden by the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1358 specifications in the <tt>datalayout</tt> keyword. The default specifications
1359 are given in this list:</p>
1360
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1361<ul>
1362 <li><tt>E</tt> - big endian</li>
Dan Gohmanfdf2e8c2010-02-23 02:44:03 +0000[diff] [blame]1363 <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]1364 <li><tt>i1:8:8</tt> - i1 is 8-bit (byte) aligned</li>
1365 <li><tt>i8:8:8</tt> - i8 is 8-bit (byte) aligned</li>
1366 <li><tt>i16:16:16</tt> - i16 is 16-bit aligned</li>
1367 <li><tt>i32:32:32</tt> - i32 is 32-bit aligned</li>
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]1368 <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]1369 alignment of 64-bits</li>
1370 <li><tt>f32:32:32</tt> - float is 32-bit aligned</li>
1371 <li><tt>f64:64:64</tt> - double is 64-bit aligned</li>
1372 <li><tt>v64:64:64</tt> - 64-bit vector is 64-bit aligned</li>
1373 <li><tt>v128:128:128</tt> - 128-bit vector is 128-bit aligned</li>
1374 <li><tt>a0:0:1</tt> - aggregates are 8-bit aligned</li>
Daniel Dunbar87bde0b2009-06-08 22:17:53 +0000[diff] [blame]1375 <li><tt>s0:64:64</tt> - stack objects are 64-bit aligned</li>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1376</ul>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1377
1378<p>When LLVM is determining the alignment for a given type, it uses the
1379 following rules:</p>
1380
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1381<ol>
1382 <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]1383 specification is used.</li>
1384
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1385 <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]1386 smallest integer type that is larger than the bitwidth of the sought type
1387 is used. If none of the specifications are larger than the bitwidth then
1388 the the largest integer type is used. For example, given the default
1389 specifications above, the i7 type will use the alignment of i8 (next
1390 largest) while both i65 and i256 will use the alignment of i64 (largest
1391 specified).</li>
1392
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1393 <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]1394 largest vector type that is smaller than the sought vector type will be
1395 used as a fall back. This happens because &lt;128 x double&gt; can be
1396 implemented in terms of 64 &lt;2 x double&gt;, for example.</li>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1397</ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1398
Chris Lattner6509f502011-10-11 23:01:39 +0000[diff] [blame]1399<p>The function of the data layout string may not be what you expect. Notably,
1400 this is not a specification from the frontend of what alignment the code
1401 generator should use.</p>
1402
1403<p>Instead, if specified, the target data layout is required to match what the
1404 ultimate <em>code generator</em> expects. This string is used by the
1405 mid-level optimizers to
1406 improve code, and this only works if it matches what the ultimate code
1407 generator uses. If you would like to generate IR that does not embed this
1408 target-specific detail into the IR, then you don't have to specify the
1409 string. This will disable some optimizations that require precise layout
1410 information, but this also prevents those optimizations from introducing
1411 target specificity into the IR.</p>
1412
1413
1414
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1415</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1416
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1417<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1418<h3>
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1419 <a name="pointeraliasing">Pointer Aliasing Rules</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1420</h3>
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1421
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1422<div>
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1423
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1424<p>Any memory access must be done through a pointer value associated
Andreas Bolka99a82052009-07-27 20:37:10 +0000[diff] [blame]1425with an address range of the memory access, otherwise the behavior
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1426is undefined. Pointer values are associated with address ranges
1427according to the following rules:</p>
1428
1429<ul>
Dan Gohman1e109622010-07-02 18:41:32 +0000[diff] [blame]1430 <li>A pointer value is associated with the addresses associated with
1431 any value it is <i>based</i> on.
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1432 <li>An address of a global variable is associated with the address
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1433 range of the variable's storage.</li>
1434 <li>The result value of an allocation instruction is associated with
1435 the address range of the allocated storage.</li>
1436 <li>A null pointer in the default address-space is associated with
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1437 no address.</li>
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1438 <li>An integer constant other than zero or a pointer value returned
1439 from a function not defined within LLVM may be associated with address
1440 ranges allocated through mechanisms other than those provided by
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1441 LLVM. Such ranges shall not overlap with any ranges of addresses
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1442 allocated by mechanisms provided by LLVM.</li>
Dan Gohman1e109622010-07-02 18:41:32 +0000[diff] [blame]1443</ul>
1444
1445<p>A pointer value is <i>based</i> on another pointer value according
1446 to the following rules:</p>
1447
1448<ul>
1449 <li>A pointer value formed from a
1450 <tt><a href="#i_getelementptr">getelementptr</a></tt> operation
1451 is <i>based</i> on the first operand of the <tt>getelementptr</tt>.</li>
1452 <li>The result value of a
1453 <tt><a href="#i_bitcast">bitcast</a></tt> is <i>based</i> on the operand
1454 of the <tt>bitcast</tt>.</li>
1455 <li>A pointer value formed by an
1456 <tt><a href="#i_inttoptr">inttoptr</a></tt> is <i>based</i> on all
1457 pointer values that contribute (directly or indirectly) to the
1458 computation of the pointer's value.</li>
1459 <li>The "<i>based</i> on" relationship is transitive.</li>
1460</ul>
1461
1462<p>Note that this definition of <i>"based"</i> is intentionally
1463 similar to the definition of <i>"based"</i> in C99, though it is
1464 slightly weaker.</p>
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1465
1466<p>LLVM IR does not associate types with memory. The result type of a
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1467<tt><a href="#i_load">load</a></tt> merely indicates the size and
1468alignment of the memory from which to load, as well as the
Dan Gohmanc22c0f32010-06-17 19:23:50 +0000[diff] [blame]1469interpretation of the value. The first operand type of a
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1470<tt><a href="#i_store">store</a></tt> similarly only indicates the size
1471and alignment of the store.</p>
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1472
1473<p>Consequently, type-based alias analysis, aka TBAA, aka
1474<tt>-fstrict-aliasing</tt>, is not applicable to general unadorned
1475LLVM IR. <a href="#metadata">Metadata</a> may be used to encode
1476additional information which specialized optimization passes may use
1477to implement type-based alias analysis.</p>
1478
1479</div>
1480
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]1481<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1482<h3>
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]1483 <a name="volatile">Volatile Memory Accesses</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1484</h3>
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]1485
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1486<div>
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]1487
1488<p>Certain memory accesses, such as <a href="#i_load"><tt>load</tt></a>s, <a
1489href="#i_store"><tt>store</tt></a>s, and <a
1490href="#int_memcpy"><tt>llvm.memcpy</tt></a>s may be marked <tt>volatile</tt>.
1491The optimizers must not change the number of volatile operations or change their
1492order of execution relative to other volatile operations. The optimizers
1493<i>may</i> change the order of volatile operations relative to non-volatile
1494operations. This is not Java's "volatile" and has no cross-thread
1495synchronization behavior.</p>
1496
1497</div>
1498
Eli Friedman5b60e1b2011-07-20 21:35:53 +0000[diff] [blame]1499<!-- ======================================================================= -->
1500<h3>
1501 <a name="memmodel">Memory Model for Concurrent Operations</a>
1502</h3>
1503
1504<div>
1505
1506<p>The LLVM IR does not define any way to start parallel threads of execution
1507or to register signal handlers. Nonetheless, there are platform-specific
1508ways to create them, and we define LLVM IR's behavior in their presence. This
1509model is inspired by the C++0x memory model.</p>
1510
Eli Friedman234bccd2011-08-22 21:35:27 +0000[diff] [blame]1511<p>For a more informal introduction to this model, see the
1512<a href="Atomics.html">LLVM Atomic Instructions and Concurrency Guide</a>.
1513
Eli Friedman5b60e1b2011-07-20 21:35:53 +0000[diff] [blame]1514<p>We define a <i>happens-before</i> partial order as the least partial order
1515that</p>
1516<ul>
1517 <li>Is a superset of single-thread program order, and</li>
1518 <li>When a <i>synchronizes-with</i> <tt>b</tt>, includes an edge from
1519 <tt>a</tt> to <tt>b</tt>. <i>Synchronizes-with</i> pairs are introduced
1520 by platform-specific techniques, like pthread locks, thread
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1521 creation, thread joining, etc., and by atomic instructions.
1522 (See also <a href="#ordering">Atomic Memory Ordering Constraints</a>).
1523 </li>
Eli Friedman5b60e1b2011-07-20 21:35:53 +0000[diff] [blame]1524</ul>
1525
1526<p>Note that program order does not introduce <i>happens-before</i> edges
1527between a thread and signals executing inside that thread.</p>
1528
1529<p>Every (defined) read operation (load instructions, memcpy, atomic
1530loads/read-modify-writes, etc.) <var>R</var> reads a series of bytes written by
1531(defined) write operations (store instructions, atomic
Eli Friedman118973a2011-07-22 03:04:45 +0000[diff] [blame]1532stores/read-modify-writes, memcpy, etc.). For the purposes of this section,
1533initialized globals are considered to have a write of the initializer which is
1534atomic and happens before any other read or write of the memory in question.
1535For each byte of a read <var>R</var>, <var>R<sub>byte</sub></var> may see
1536any write to the same byte, except:</p>
Eli Friedman5b60e1b2011-07-20 21:35:53 +0000[diff] [blame]1537
1538<ul>
1539 <li>If <var>write<sub>1</sub></var> happens before
1540 <var>write<sub>2</sub></var>, and <var>write<sub>2</sub></var> happens
1541 before <var>R<sub>byte</sub></var>, then <var>R<sub>byte</sub></var>
Eli Friedman118973a2011-07-22 03:04:45 +0000[diff] [blame]1542 does not see <var>write<sub>1</sub></var>.
Bill Wendling0246bb72011-07-31 06:45:03 +0000[diff] [blame]1543 <li>If <var>R<sub>byte</sub></var> happens before
1544 <var>write<sub>3</sub></var>, then <var>R<sub>byte</sub></var> does not
1545 see <var>write<sub>3</sub></var>.
Eli Friedman5b60e1b2011-07-20 21:35:53 +0000[diff] [blame]1546</ul>
1547
1548<p>Given that definition, <var>R<sub>byte</sub></var> is defined as follows:
1549<ul>
Eli Friedman234bccd2011-08-22 21:35:27 +0000[diff] [blame]1550 <li>If <var>R</var> is volatile, the result is target-dependent. (Volatile
1551 is supposed to give guarantees which can support
1552 <code>sig_atomic_t</code> in C/C++, and may be used for accesses to
1553 addresses which do not behave like normal memory. It does not generally
1554 provide cross-thread synchronization.)
1555 <li>Otherwise, if there is no write to the same byte that happens before
Eli Friedman5b60e1b2011-07-20 21:35:53 +0000[diff] [blame]1556 <var>R<sub>byte</sub></var>, <var>R<sub>byte</sub></var> returns
1557 <tt>undef</tt> for that byte.
Eli Friedman118973a2011-07-22 03:04:45 +0000[diff] [blame]1558 <li>Otherwise, if <var>R<sub>byte</sub></var> may see exactly one write,
Eli Friedman5b60e1b2011-07-20 21:35:53 +0000[diff] [blame]1559 <var>R<sub>byte</sub></var> returns the value written by that
1560 write.</li>
Eli Friedman118973a2011-07-22 03:04:45 +0000[diff] [blame]1561 <li>Otherwise, if <var>R</var> is atomic, and all the writes
1562 <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]1563 values written. See the <a href="#ordering">Atomic Memory Ordering
1564 Constraints</a> section for additional constraints on how the choice
1565 is made.
Eli Friedman5b60e1b2011-07-20 21:35:53 +0000[diff] [blame]1566 <li>Otherwise <var>R<sub>byte</sub></var> returns <tt>undef</tt>.</li>
1567</ul>
1568
1569<p><var>R</var> returns the value composed of the series of bytes it read.
1570This implies that some bytes within the value may be <tt>undef</tt>
1571<b>without</b> the entire value being <tt>undef</tt>. Note that this only
1572defines the semantics of the operation; it doesn't mean that targets will
1573emit more than one instruction to read the series of bytes.</p>
1574
1575<p>Note that in cases where none of the atomic intrinsics are used, this model
1576places only one restriction on IR transformations on top of what is required
1577for single-threaded execution: introducing a store to a byte which might not
Eli Friedman101c81d2011-08-02 01:15:34 +0000[diff] [blame]1578otherwise be stored is not allowed in general. (Specifically, in the case
1579where another thread might write to and read from an address, introducing a
1580store can change a load that may see exactly one write into a load that may
1581see multiple writes.)</p>
Eli Friedman5b60e1b2011-07-20 21:35:53 +0000[diff] [blame]1582
1583<!-- FIXME: This model assumes all targets where concurrency is relevant have
1584a byte-size store which doesn't affect adjacent bytes. As far as I can tell,
1585none of the backends currently in the tree fall into this category; however,
1586there might be targets which care. If there are, we want a paragraph
1587like the following:
1588
1589Targets may specify that stores narrower than a certain width are not
1590available; on such a target, for the purposes of this model, treat any
1591non-atomic write with an alignment or width less than the minimum width
1592as if it writes to the relevant surrounding bytes.
1593-->
1594
1595</div>
1596
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1597<!-- ======================================================================= -->
NAKAMURA Takumib5bb29c2011-08-12 06:17:17 +0000[diff] [blame]1598<h3>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1599 <a name="ordering">Atomic Memory Ordering Constraints</a>
NAKAMURA Takumib5bb29c2011-08-12 06:17:17 +0000[diff] [blame]1600</h3>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1601
NAKAMURA Takumib5bb29c2011-08-12 06:17:17 +0000[diff] [blame]1602<div>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1603
1604<p>Atomic instructions (<a href="#i_cmpxchg"><code>cmpxchg</code></a>,
Eli Friedman21006d42011-08-09 23:02:53 +0000[diff] [blame]1605<a href="#i_atomicrmw"><code>atomicrmw</code></a>,
1606<a href="#i_fence"><code>fence</code></a>,
1607<a href="#i_load"><code>atomic load</code></a>, and
Eli Friedman8fa281a2011-08-09 23:26:12 +0000[diff] [blame]1608<a href="#i_store"><code>atomic store</code></a>) take an ordering parameter
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1609that determines which other atomic instructions on the same address they
1610<i>synchronize with</i>. These semantics are borrowed from Java and C++0x,
1611but are somewhat more colloquial. If these descriptions aren't precise enough,
Eli Friedman234bccd2011-08-22 21:35:27 +0000[diff] [blame]1612check those specs (see spec references in the
1613<a href="Atomic.html#introduction">atomics guide</a>).
1614<a href="#i_fence"><code>fence</code></a> instructions
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1615treat these orderings somewhat differently since they don't take an address.
1616See that instruction's documentation for details.</p>
1617
Eli Friedman234bccd2011-08-22 21:35:27 +0000[diff] [blame]1618<p>For a simpler introduction to the ordering constraints, see the
1619<a href="Atomics.html">LLVM Atomic Instructions and Concurrency Guide</a>.</p>
1620
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1621<dl>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1622<dt><code>unordered</code></dt>
1623<dd>The set of values that can be read is governed by the happens-before
1624partial order. A value cannot be read unless some operation wrote it.
1625This is intended to provide a guarantee strong enough to model Java's
1626non-volatile shared variables. This ordering cannot be specified for
1627read-modify-write operations; it is not strong enough to make them atomic
1628in any interesting way.</dd>
1629<dt><code>monotonic</code></dt>
1630<dd>In addition to the guarantees of <code>unordered</code>, there is a single
1631total order for modifications by <code>monotonic</code> operations on each
1632address. All modification orders must be compatible with the happens-before
1633order. There is no guarantee that the modification orders can be combined to
1634a global total order for the whole program (and this often will not be
1635possible). The read in an atomic read-modify-write operation
1636(<a href="#i_cmpxchg"><code>cmpxchg</code></a> and
1637<a href="#i_atomicrmw"><code>atomicrmw</code></a>)
1638reads the value in the modification order immediately before the value it
1639writes. If one atomic read happens before another atomic read of the same
1640address, the later read must see the same value or a later value in the
1641address's modification order. This disallows reordering of
1642<code>monotonic</code> (or stronger) operations on the same address. If an
1643address is written <code>monotonic</code>ally by one thread, and other threads
1644<code>monotonic</code>ally read that address repeatedly, the other threads must
Eli Friedman234bccd2011-08-22 21:35:27 +0000[diff] [blame]1645eventually see the write. This corresponds to the C++0x/C1x
1646<code>memory_order_relaxed</code>.</dd>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1647<dt><code>acquire</code></dt>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1648<dd>In addition to the guarantees of <code>monotonic</code>,
Eli Friedmanc264b2f2011-08-24 20:28:39 +0000[diff] [blame]1649a <i>synchronizes-with</i> edge may be formed with a <code>release</code>
1650operation. This is intended to model C++'s <code>memory_order_acquire</code>.</dd>
1651<dt><code>release</code></dt>
1652<dd>In addition to the guarantees of <code>monotonic</code>, if this operation
1653writes a value which is subsequently read by an <code>acquire</code> operation,
1654it <i>synchronizes-with</i> that operation. (This isn't a complete
1655description; see the C++0x definition of a release sequence.) This corresponds
1656to the C++0x/C1x <code>memory_order_release</code>.</dd>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1657<dt><code>acq_rel</code> (acquire+release)</dt><dd>Acts as both an
Eli Friedman234bccd2011-08-22 21:35:27 +0000[diff] [blame]1658<code>acquire</code> and <code>release</code> operation on its address.
1659This corresponds to the C++0x/C1x <code>memory_order_acq_rel</code>.</dd>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1660<dt><code>seq_cst</code> (sequentially consistent)</dt><dd>
1661<dd>In addition to the guarantees of <code>acq_rel</code>
1662(<code>acquire</code> for an operation which only reads, <code>release</code>
1663for an operation which only writes), there is a global total order on all
1664sequentially-consistent operations on all addresses, which is consistent with
1665the <i>happens-before</i> partial order and with the modification orders of
1666all the affected addresses. Each sequentially-consistent read sees the last
Eli Friedman234bccd2011-08-22 21:35:27 +0000[diff] [blame]1667preceding write to the same address in this global order. This corresponds
1668to the C++0x/C1x <code>memory_order_seq_cst</code> and Java volatile.</dd>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1669</dl>
1670
1671<p id="singlethread">If an atomic operation is marked <code>singlethread</code>,
1672it only <i>synchronizes with</i> or participates in modification and seq_cst
1673total orderings with other operations running in the same thread (for example,
1674in signal handlers).</p>
1675
1676</div>
1677
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1678</div>
1679
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1680<!-- *********************************************************************** -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1681<h2><a name="typesystem">Type System</a></h2>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1682<!-- *********************************************************************** -->
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1683
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1684<div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1685
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1686<p>The LLVM type system is one of the most important features of the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1687 intermediate representation. Being typed enables a number of optimizations
1688 to be performed on the intermediate representation directly, without having
1689 to do extra analyses on the side before the transformation. A strong type
1690 system makes it easier to read the generated code and enables novel analyses
1691 and transformations that are not feasible to perform on normal three address
1692 code representations.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1693
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1694<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1695<h3>
1696 <a name="t_classifications">Type Classifications</a>
1697</h3>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1698
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1699<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1700
1701<p>The types fall into a few useful classifications:</p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1702
1703<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1704 <tbody>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1705 <tr><th>Classification</th><th>Types</th></tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1706 <tr>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1707 <td><a href="#t_integer">integer</a></td>
Reid Spencer2b916312007-05-16 18:44:01 +0000[diff] [blame]1708 <td><tt>i1, i2, i3, ... i8, ... i16, ... i32, ... i64, ... </tt></td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1709 </tr>
1710 <tr>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1711 <td><a href="#t_floating">floating point</a></td>
1712 <td><tt>float, double, x86_fp80, fp128, ppc_fp128</tt></td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1713 </tr>
1714 <tr>
1715 <td><a name="t_firstclass">first class</a></td>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1716 <td><a href="#t_integer">integer</a>,
1717 <a href="#t_floating">floating point</a>,
1718 <a href="#t_pointer">pointer</a>,
Dan Gohman0066db62008-06-18 18:42:13 +0000[diff] [blame]1719 <a href="#t_vector">vector</a>,
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]1720 <a href="#t_struct">structure</a>,
1721 <a href="#t_array">array</a>,
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1722 <a href="#t_label">label</a>,
1723 <a href="#t_metadata">metadata</a>.
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1724 </td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1725 </tr>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1726 <tr>
1727 <td><a href="#t_primitive">primitive</a></td>
1728 <td><a href="#t_label">label</a>,
1729 <a href="#t_void">void</a>,
Tobias Grosser05387292010-12-28 20:29:31 +0000[diff] [blame]1730 <a href="#t_integer">integer</a>,
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1731 <a href="#t_floating">floating point</a>,
Dale Johannesen21fe99b2010-10-01 00:48:59 +0000[diff] [blame]1732 <a href="#t_x86mmx">x86mmx</a>,
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1733 <a href="#t_metadata">metadata</a>.</td>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1734 </tr>
1735 <tr>
1736 <td><a href="#t_derived">derived</a></td>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]1737 <td><a href="#t_array">array</a>,
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1738 <a href="#t_function">function</a>,
1739 <a href="#t_pointer">pointer</a>,
1740 <a href="#t_struct">structure</a>,
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1741 <a href="#t_vector">vector</a>,
1742 <a href="#t_opaque">opaque</a>.
Dan Gohman01ac1012008-10-14 16:32:04 +0000[diff] [blame]1743 </td>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1744 </tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1745 </tbody>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1746</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1747
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1748<p>The <a href="#t_firstclass">first class</a> types are perhaps the most
1749 important. Values of these types are the only ones which can be produced by
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]1750 instructions.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1751
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1752</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1753
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1754<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1755<h3>
1756 <a name="t_primitive">Primitive Types</a>
1757</h3>
Chris Lattner8f8c7b72008-01-04 04:34:14 +0000[diff] [blame]1758
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1759<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1760
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1761<p>The primitive types are the fundamental building blocks of the LLVM
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1762 system.</p>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1763
1764<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1765<h4>
1766 <a name="t_integer">Integer Type</a>
1767</h4>
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]1768
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1769<div>
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]1770
1771<h5>Overview:</h5>
1772<p>The integer type is a very simple type that simply specifies an arbitrary
1773 bit width for the integer type desired. Any bit width from 1 bit to
1774 2<sup>23</sup>-1 (about 8 million) can be specified.</p>
1775
1776<h5>Syntax:</h5>
1777<pre>
1778 iN
1779</pre>
1780
1781<p>The number of bits the integer will occupy is specified by the <tt>N</tt>
1782 value.</p>
1783
1784<h5>Examples:</h5>
1785<table class="layout">
1786 <tr class="layout">
1787 <td class="left"><tt>i1</tt></td>
1788 <td class="left">a single-bit integer.</td>
1789 </tr>
1790 <tr class="layout">
1791 <td class="left"><tt>i32</tt></td>
1792 <td class="left">a 32-bit integer.</td>
1793 </tr>
1794 <tr class="layout">
1795 <td class="left"><tt>i1942652</tt></td>
1796 <td class="left">a really big integer of over 1 million bits.</td>
1797 </tr>
1798</table>
1799
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]1800</div>
1801
1802<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1803<h4>
1804 <a name="t_floating">Floating Point Types</a>
1805</h4>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1806
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1807<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1808
1809<table>
1810 <tbody>
1811 <tr><th>Type</th><th>Description</th></tr>
1812 <tr><td><tt>float</tt></td><td>32-bit floating point value</td></tr>
1813 <tr><td><tt>double</tt></td><td>64-bit floating point value</td></tr>
1814 <tr><td><tt>fp128</tt></td><td>128-bit floating point value (112-bit mantissa)</td></tr>
1815 <tr><td><tt>x86_fp80</tt></td><td>80-bit floating point value (X87)</td></tr>
1816 <tr><td><tt>ppc_fp128</tt></td><td>128-bit floating point value (two 64-bits)</td></tr>
1817 </tbody>
1818</table>
1819
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1820</div>
1821
1822<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1823<h4>
1824 <a name="t_x86mmx">X86mmx Type</a>
1825</h4>
Dale Johannesen21fe99b2010-10-01 00:48:59 +0000[diff] [blame]1826
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1827<div>
Dale Johannesen21fe99b2010-10-01 00:48:59 +0000[diff] [blame]1828
1829<h5>Overview:</h5>
1830<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>
1831
1832<h5>Syntax:</h5>
1833<pre>
Dale Johannesen473a8c82010-10-01 01:07:02 +0000[diff] [blame]1834 x86mmx
Dale Johannesen21fe99b2010-10-01 00:48:59 +0000[diff] [blame]1835</pre>
1836
1837</div>
1838
1839<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1840<h4>
1841 <a name="t_void">Void Type</a>
1842</h4>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1843
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1844<div>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1845
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1846<h5>Overview:</h5>
1847<p>The void type does not represent any value and has no size.</p>
1848
1849<h5>Syntax:</h5>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1850<pre>
1851 void
1852</pre>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1853
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1854</div>
1855
1856<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1857<h4>
1858 <a name="t_label">Label Type</a>
1859</h4>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1860
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1861<div>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1862
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1863<h5>Overview:</h5>
1864<p>The label type represents code labels.</p>
1865
1866<h5>Syntax:</h5>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1867<pre>
1868 label
1869</pre>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1870
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1871</div>
1872
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1873<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1874<h4>
1875 <a name="t_metadata">Metadata Type</a>
1876</h4>
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1877
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1878<div>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1879
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1880<h5>Overview:</h5>
Nick Lewyckyc261df92009-09-27 23:27:42 +0000[diff] [blame]1881<p>The metadata type represents embedded metadata. No derived types may be
1882 created from metadata except for <a href="#t_function">function</a>
1883 arguments.
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1884
1885<h5>Syntax:</h5>
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1886<pre>
1887 metadata
1888</pre>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1889
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1890</div>
1891
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1892</div>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1893
1894<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1895<h3>
1896 <a name="t_derived">Derived Types</a>
1897</h3>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1898
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1899<div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1900
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1901<p>The real power in LLVM comes from the derived types in the system. This is
1902 what allows a programmer to represent arrays, functions, pointers, and other
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]1903 useful types. Each of these types contain one or more element types which
1904 may be a primitive type, or another derived type. For example, it is
1905 possible to have a two dimensional array, using an array as the element type
1906 of another array.</p>
Dan Gohmand8791e52009-01-24 15:58:40 +0000[diff] [blame]1907
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]1908<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1909<h4>
1910 <a name="t_aggregate">Aggregate Types</a>
1911</h4>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]1912
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1913<div>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]1914
1915<p>Aggregate Types are a subset of derived types that can contain multiple
1916 member types. <a href="#t_array">Arrays</a>,
Chris Lattner61c70e92010-08-28 04:09:24 +0000[diff] [blame]1917 <a href="#t_struct">structs</a>, and <a href="#t_vector">vectors</a> are
1918 aggregate types.</p>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]1919
1920</div>
1921
Reid Spencer2b916312007-05-16 18:44:01 +0000[diff] [blame]1922<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1923<h4>
1924 <a name="t_array">Array Type</a>
1925</h4>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1926
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1927<div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1928
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1929<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1930<p>The array type is a very simple derived type that arranges elements
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1931 sequentially in memory. The array type requires a size (number of elements)
1932 and an underlying data type.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1933
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1934<h5>Syntax:</h5>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1935<pre>
1936 [&lt;# elements&gt; x &lt;elementtype&gt;]
1937</pre>
1938
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1939<p>The number of elements is a constant integer value; <tt>elementtype</tt> may
1940 be any type with a size.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1941
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1942<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1943<table class="layout">
1944 <tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1945 <td class="left"><tt>[40 x i32]</tt></td>
1946 <td class="left">Array of 40 32-bit integer values.</td>
1947 </tr>
1948 <tr class="layout">
1949 <td class="left"><tt>[41 x i32]</tt></td>
1950 <td class="left">Array of 41 32-bit integer values.</td>
1951 </tr>
1952 <tr class="layout">
1953 <td class="left"><tt>[4 x i8]</tt></td>
1954 <td class="left">Array of 4 8-bit integer values.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1955 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1956</table>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1957<p>Here are some examples of multidimensional arrays:</p>
1958<table class="layout">
1959 <tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1960 <td class="left"><tt>[3 x [4 x i32]]</tt></td>
1961 <td class="left">3x4 array of 32-bit integer values.</td>
1962 </tr>
1963 <tr class="layout">
1964 <td class="left"><tt>[12 x [10 x float]]</tt></td>
1965 <td class="left">12x10 array of single precision floating point values.</td>
1966 </tr>
1967 <tr class="layout">
1968 <td class="left"><tt>[2 x [3 x [4 x i16]]]</tt></td>
1969 <td class="left">2x3x4 array of 16-bit integer values.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1970 </tr>
1971</table>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]1972
Dan Gohman7657f6b2009-11-09 19:01:53 +0000[diff] [blame]1973<p>There is no restriction on indexing beyond the end of the array implied by
1974 a static type (though there are restrictions on indexing beyond the bounds
1975 of an allocated object in some cases). This means that single-dimension
1976 'variable sized array' addressing can be implemented in LLVM with a zero
1977 length array type. An implementation of 'pascal style arrays' in LLVM could
1978 use the type "<tt>{ i32, [0 x float]}</tt>", for example.</p>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]1979
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1980</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1981
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1982<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1983<h4>
1984 <a name="t_function">Function Type</a>
1985</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1986
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1987<div>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]1988
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1989<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1990<p>The function type can be thought of as a function signature. It consists of
1991 a return type and a list of formal parameter types. The return type of a
Chris Lattner61c70e92010-08-28 04:09:24 +0000[diff] [blame]1992 function type is a first class type or a void type.</p>
Devang Patelc3fc6df2008-03-10 20:49:15 +0000[diff] [blame]1993
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1994<h5>Syntax:</h5>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]1995<pre>
Nick Lewycky51386942009-09-27 07:55:32 +0000[diff] [blame]1996 &lt;returntype&gt; (&lt;parameter list&gt;)
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]1997</pre>
1998
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]1999<p>...where '<tt>&lt;parameter list&gt;</tt>' is a comma-separated list of type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2000 specifiers. Optionally, the parameter list may include a type <tt>...</tt>,
2001 which indicates that the function takes a variable number of arguments.
2002 Variable argument functions can access their arguments with
2003 the <a href="#int_varargs">variable argument handling intrinsic</a>
Chris Lattner0724fbd2010-03-02 06:36:51 +0000[diff] [blame]2004 functions. '<tt>&lt;returntype&gt;</tt>' is any type except
Nick Lewyckyc261df92009-09-27 23:27:42 +0000[diff] [blame]2005 <a href="#t_label">label</a>.</p>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]2006
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2007<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]2008<table class="layout">
2009 <tr class="layout">
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]2010 <td class="left"><tt>i32 (i32)</tt></td>
2011 <td class="left">function taking an <tt>i32</tt>, returning an <tt>i32</tt>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]2012 </td>
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]2013 </tr><tr class="layout">
Chris Lattner0724fbd2010-03-02 06:36:51 +0000[diff] [blame]2014 <td class="left"><tt>float&nbsp;(i16,&nbsp;i32&nbsp;*)&nbsp;*
Reid Spencerf17a0b72006-12-31 07:20:23 +0000[diff] [blame]2015 </tt></td>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]2016 <td class="left"><a href="#t_pointer">Pointer</a> to a function that takes
Chris Lattner0724fbd2010-03-02 06:36:51 +0000[diff] [blame]2017 an <tt>i16</tt> and a <a href="#t_pointer">pointer</a> to <tt>i32</tt>,
2018 returning <tt>float</tt>.
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]2019 </td>
2020 </tr><tr class="layout">
2021 <td class="left"><tt>i32 (i8*, ...)</tt></td>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]2022 <td class="left">A vararg function that takes at least one
2023 <a href="#t_pointer">pointer</a> to <tt>i8 </tt> (char in C),
2024 which returns an integer. This is the signature for <tt>printf</tt> in
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]2025 LLVM.
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]2026 </td>
Devang Patela582f402008-03-24 05:35:41 +0000[diff] [blame]2027 </tr><tr class="layout">
2028 <td class="left"><tt>{i32, i32} (i32)</tt></td>
Nick Lewycky51386942009-09-27 07:55:32 +0000[diff] [blame]2029 <td class="left">A function taking an <tt>i32</tt>, returning a
2030 <a href="#t_struct">structure</a> containing two <tt>i32</tt> values
Devang Patela582f402008-03-24 05:35:41 +0000[diff] [blame]2031 </td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]2032 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2033</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]2034
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2035</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2036
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2037<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2038<h4>
2039 <a name="t_struct">Structure Type</a>
2040</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2041
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2042<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2043
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2044<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2045<p>The structure type is used to represent a collection of data members together
Chris Lattner1afcace2011-07-09 17:41:24 +0000[diff] [blame]2046 in memory. The elements of a structure may be any type that has a size.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2047
Jeffrey Yasskin7a088cf2010-01-11 19:19:26 +0000[diff] [blame]2048<p>Structures in memory are accessed using '<tt><a href="#i_load">load</a></tt>'
2049 and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a field
2050 with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.
2051 Structures in registers are accessed using the
2052 '<tt><a href="#i_extractvalue">extractvalue</a></tt>' and
2053 '<tt><a href="#i_insertvalue">insertvalue</a></tt>' instructions.</p>
Chris Lattner1afcace2011-07-09 17:41:24 +0000[diff] [blame]2054
2055<p>Structures may optionally be "packed" structures, which indicate that the
2056 alignment of the struct is one byte, and that there is no padding between
Chris Lattner2c38d652011-08-12 17:31:02 +0000[diff] [blame]2057 the elements. In non-packed structs, padding between field types is inserted
2058 as defined by the TargetData string in the module, which is required to match
Chris Lattnere4617b02011-10-11 23:02:17 +0000[diff] [blame]2059 what the underlying code generator expects.</p>
Chris Lattner1afcace2011-07-09 17:41:24 +0000[diff] [blame]2060
Chris Lattner2c38d652011-08-12 17:31:02 +0000[diff] [blame]2061<p>Structures can either be "literal" or "identified". A literal structure is
2062 defined inline with other types (e.g. <tt>{i32, i32}*</tt>) whereas identified
2063 types are always defined at the top level with a name. Literal types are
2064 uniqued by their contents and can never be recursive or opaque since there is
Chris Lattneraa175c32011-08-12 18:12:40 +0000[diff] [blame]2065 no way to write one. Identified types can be recursive, can be opaqued, and are
Chris Lattner2c38d652011-08-12 17:31:02 +0000[diff] [blame]2066 never uniqued.
Chris Lattner1afcace2011-07-09 17:41:24 +0000[diff] [blame]2067</p>
2068
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2069<h5>Syntax:</h5>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]2070<pre>
Chris Lattner2c38d652011-08-12 17:31:02 +0000[diff] [blame]2071 %T1 = type { &lt;type list&gt; } <i>; Identified normal struct type</i>
2072 %T2 = type &lt;{ &lt;type list&gt; }&gt; <i>; Identified packed struct type</i>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]2073</pre>
Chris Lattner1afcace2011-07-09 17:41:24 +0000[diff] [blame]2074
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2075<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]2076<table class="layout">
2077 <tr class="layout">
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]2078 <td class="left"><tt>{ i32, i32, i32 }</tt></td>
2079 <td class="left">A triple of three <tt>i32</tt> values</td>
Chris Lattner1afcace2011-07-09 17:41:24 +0000[diff] [blame]2080 </tr>
2081 <tr class="layout">
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]2082 <td class="left"><tt>{&nbsp;float,&nbsp;i32&nbsp;(i32)&nbsp;*&nbsp;}</tt></td>
2083 <td class="left">A pair, where the first element is a <tt>float</tt> and the
2084 second element is a <a href="#t_pointer">pointer</a> to a
2085 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
2086 an <tt>i32</tt>.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]2087 </tr>
Chris Lattner1afcace2011-07-09 17:41:24 +0000[diff] [blame]2088 <tr class="layout">
2089 <td class="left"><tt>&lt;{ i8, i32 }&gt;</tt></td>
2090 <td class="left">A packed struct known to be 5 bytes in size.</td>
2091 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2092</table>
Dan Gohmand8791e52009-01-24 15:58:40 +0000[diff] [blame]2093
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2094</div>
Chris Lattner1afcace2011-07-09 17:41:24 +0000[diff] [blame]2095
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2096<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2097<h4>
Chris Lattner628ed392011-07-23 19:59:08 +0000[diff] [blame]2098 <a name="t_opaque">Opaque Structure Types</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2099</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2100
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2101<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2102
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]2103<h5>Overview:</h5>
Chris Lattner628ed392011-07-23 19:59:08 +0000[diff] [blame]2104<p>Opaque structure types are used to represent named structure types that do
2105 not have a body specified. This corresponds (for example) to the C notion of
2106 a forward declared structure.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2107
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]2108<h5>Syntax:</h5>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]2109<pre>
Chris Lattner1afcace2011-07-09 17:41:24 +0000[diff] [blame]2110 %X = type opaque
2111 %52 = type opaque
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]2112</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2113
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]2114<h5>Examples:</h5>
2115<table class="layout">
2116 <tr class="layout">
Chris Lattner1afcace2011-07-09 17:41:24 +0000[diff] [blame]2117 <td class="left"><tt>opaque</tt></td>
2118 <td class="left">An opaque type.</td>
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]2119 </tr>
2120</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2121
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]2122</div>
2123
Chris Lattner1afcace2011-07-09 17:41:24 +0000[diff] [blame]2124
2125
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]2126<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2127<h4>
2128 <a name="t_pointer">Pointer Type</a>
2129</h4>
Chris Lattner0fd4a272009-02-08 19:53:29 +0000[diff] [blame]2130
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2131<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2132
2133<h5>Overview:</h5>
Dan Gohmanff3ef322010-02-25 16:50:07 +0000[diff] [blame]2134<p>The pointer type is used to specify memory locations.
2135 Pointers are commonly used to reference objects in memory.</p>
2136
2137<p>Pointer types may have an optional address space attribute defining the
2138 numbered address space where the pointed-to object resides. The default
2139 address space is number zero. The semantics of non-zero address
2140 spaces are target-specific.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2141
2142<p>Note that LLVM does not permit pointers to void (<tt>void*</tt>) nor does it
2143 permit pointers to labels (<tt>label*</tt>). Use <tt>i8*</tt> instead.</p>
Chris Lattner0fd4a272009-02-08 19:53:29 +0000[diff] [blame]2144
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2145<h5>Syntax:</h5>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]2146<pre>
2147 &lt;type&gt; *
2148</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2149
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2150<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]2151<table class="layout">
2152 <tr class="layout">
Dan Gohman2a08c532009-01-04 23:44:43 +0000[diff] [blame]2153 <td class="left"><tt>[4 x i32]*</tt></td>
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]2154 <td class="left">A <a href="#t_pointer">pointer</a> to <a
2155 href="#t_array">array</a> of four <tt>i32</tt> values.</td>
2156 </tr>
2157 <tr class="layout">
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]2158 <td class="left"><tt>i32 (i32*) *</tt></td>
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]2159 <td class="left"> A <a href="#t_pointer">pointer</a> to a <a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2160 href="#t_function">function</a> that takes an <tt>i32*</tt>, returning an
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]2161 <tt>i32</tt>.</td>
2162 </tr>
2163 <tr class="layout">
2164 <td class="left"><tt>i32 addrspace(5)*</tt></td>
2165 <td class="left">A <a href="#t_pointer">pointer</a> to an <tt>i32</tt> value
2166 that resides in address space #5.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]2167 </tr>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2168</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2169
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2170</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]2171
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]2172<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2173<h4>
2174 <a name="t_vector">Vector Type</a>
2175</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2176
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2177<div>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]2178
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]2179<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2180<p>A vector type is a simple derived type that represents a vector of elements.
2181 Vector types are used when multiple primitive data are operated in parallel
2182 using a single instruction (SIMD). A vector type requires a size (number of
Duncan Sandsd40d14e2009-11-27 13:38:03 +0000[diff] [blame]2183 elements) and an underlying primitive data type. Vector types are considered
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2184 <a href="#t_firstclass">first class</a>.</p>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]2185
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]2186<h5>Syntax:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]2187<pre>
2188 &lt; &lt;# elements&gt; x &lt;elementtype&gt; &gt;
2189</pre>
2190
Chris Lattner7d2e7be2010-10-10 18:20:35 +0000[diff] [blame]2191<p>The number of elements is a constant integer value larger than 0; elementtype
Nadav Rotem16087692011-12-05 06:29:09 +0000[diff] [blame]2192 may be any integer or floating point type, or a pointer to these types.
2193 Vectors of size zero are not allowed. </p>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]2194
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]2195<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]2196<table class="layout">
2197 <tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]2198 <td class="left"><tt>&lt;4 x i32&gt;</tt></td>
2199 <td class="left">Vector of 4 32-bit integer values.</td>
2200 </tr>
2201 <tr class="layout">
2202 <td class="left"><tt>&lt;8 x float&gt;</tt></td>
2203 <td class="left">Vector of 8 32-bit floating-point values.</td>
2204 </tr>
2205 <tr class="layout">
2206 <td class="left"><tt>&lt;2 x i64&gt;</tt></td>
2207 <td class="left">Vector of 2 64-bit integer values.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]2208 </tr>
Nadav Rotem16087692011-12-05 06:29:09 +0000[diff] [blame]2209 <tr class="layout">
2210 <td class="left"><tt>&lt;4 x i64*&gt;</tt></td>
2211 <td class="left">Vector of 4 pointers to 64-bit integer values.</td>
2212 </tr>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]2213</table>
Dan Gohmand8791e52009-01-24 15:58:40 +0000[diff] [blame]2214
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2215</div>
2216
Bill Wendlingaf75f0c2011-07-31 06:47:33 +0000[diff] [blame]2217</div>
2218
NAKAMURA Takumi4b2e07a2011-10-31 13:04:26 +0000[diff] [blame]2219</div>
2220
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2221<!-- *********************************************************************** -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2222<h2><a name="constants">Constants</a></h2>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2223<!-- *********************************************************************** -->
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<p>LLVM has several different basic types of constants. This section describes
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2228 them all and their syntax.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2229
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2230<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2231<h3>
2232 <a name="simpleconstants">Simple Constants</a>
2233</h3>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2234
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2235<div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2236
2237<dl>
2238 <dt><b>Boolean constants</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2239 <dd>The two strings '<tt>true</tt>' and '<tt>false</tt>' are both valid
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]2240 constants of the <tt><a href="#t_integer">i1</a></tt> type.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2241
2242 <dt><b>Integer constants</b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2243 <dd>Standard integers (such as '4') are constants of
2244 the <a href="#t_integer">integer</a> type. Negative numbers may be used
2245 with integer types.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2246
2247 <dt><b>Floating point constants</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2248 <dd>Floating point constants use standard decimal notation (e.g. 123.421),
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2249 exponential notation (e.g. 1.23421e+2), or a more precise hexadecimal
2250 notation (see below). The assembler requires the exact decimal value of a
2251 floating-point constant. For example, the assembler accepts 1.25 but
2252 rejects 1.3 because 1.3 is a repeating decimal in binary. Floating point
2253 constants must have a <a href="#t_floating">floating point</a> type. </dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2254
2255 <dt><b>Null pointer constants</b></dt>
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]2256 <dd>The identifier '<tt>null</tt>' is recognized as a null pointer constant
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2257 and must be of <a href="#t_pointer">pointer type</a>.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2258</dl>
2259
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2260<p>The one non-intuitive notation for constants is the hexadecimal form of
2261 floating point constants. For example, the form '<tt>double
2262 0x432ff973cafa8000</tt>' is equivalent to (but harder to read than)
2263 '<tt>double 4.5e+15</tt>'. The only time hexadecimal floating point
2264 constants are required (and the only time that they are generated by the
2265 disassembler) is when a floating point constant must be emitted but it cannot
2266 be represented as a decimal floating point number in a reasonable number of
2267 digits. For example, NaN's, infinities, and other special values are
2268 represented in their IEEE hexadecimal format so that assembly and disassembly
2269 do not cause any bits to change in the constants.</p>
2270
Dale Johannesenbd5e5a82009-02-11 22:14:51 +0000[diff] [blame]2271<p>When using the hexadecimal form, constants of types float and double are
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2272 represented using the 16-digit form shown above (which matches the IEEE754
2273 representation for double); float values must, however, be exactly
2274 representable as IEE754 single precision. Hexadecimal format is always used
2275 for long double, and there are three forms of long double. The 80-bit format
2276 used by x86 is represented as <tt>0xK</tt> followed by 20 hexadecimal digits.
2277 The 128-bit format used by PowerPC (two adjacent doubles) is represented
2278 by <tt>0xM</tt> followed by 32 hexadecimal digits. The IEEE 128-bit format
2279 is represented by <tt>0xL</tt> followed by 32 hexadecimal digits; no
2280 currently supported target uses this format. Long doubles will only work if
2281 they match the long double format on your target. All hexadecimal formats
2282 are big-endian (sign bit at the left).</p>
2283
Dale Johannesen21fe99b2010-10-01 00:48:59 +0000[diff] [blame]2284<p>There are no constants of type x86mmx.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2285</div>
2286
2287<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2288<h3>
Bill Wendlingd9fe2982009-07-20 02:32:41 +0000[diff] [blame]2289<a name="aggregateconstants"></a> <!-- old anchor -->
2290<a name="complexconstants">Complex Constants</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2291</h3>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2292
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2293<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2294
Chris Lattner70882792009-02-28 18:32:25 +0000[diff] [blame]2295<p>Complex constants are a (potentially recursive) combination of simple
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2296 constants and smaller complex constants.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2297
2298<dl>
2299 <dt><b>Structure constants</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2300 <dd>Structure constants are represented with notation similar to structure
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2301 type definitions (a comma separated list of elements, surrounded by braces
2302 (<tt>{}</tt>)). For example: "<tt>{ i32 4, float 17.0, i32* @G }</tt>",
2303 where "<tt>@G</tt>" is declared as "<tt>@G = external global i32</tt>".
2304 Structure constants must have <a href="#t_struct">structure type</a>, and
2305 the number and types of elements must match those specified by the
2306 type.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2307
2308 <dt><b>Array constants</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2309 <dd>Array constants are represented with notation similar to array type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2310 definitions (a comma separated list of elements, surrounded by square
2311 brackets (<tt>[]</tt>)). For example: "<tt>[ i32 42, i32 11, i32 74
2312 ]</tt>". Array constants must have <a href="#t_array">array type</a>, and
2313 the number and types of elements must match those specified by the
2314 type.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2315
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2316 <dt><b>Vector constants</b></dt>
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2317 <dd>Vector constants are represented with notation similar to vector type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2318 definitions (a comma separated list of elements, surrounded by
2319 less-than/greater-than's (<tt>&lt;&gt;</tt>)). For example: "<tt>&lt; i32
2320 42, i32 11, i32 74, i32 100 &gt;</tt>". Vector constants must
2321 have <a href="#t_vector">vector type</a>, and the number and types of
2322 elements must match those specified by the type.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2323
2324 <dt><b>Zero initialization</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2325 <dd>The string '<tt>zeroinitializer</tt>' can be used to zero initialize a
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]2326 value to zero of <em>any</em> type, including scalar and
2327 <a href="#t_aggregate">aggregate</a> types.
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2328 This is often used to avoid having to print large zero initializers
2329 (e.g. for large arrays) and is always exactly equivalent to using explicit
2330 zero initializers.</dd>
Nick Lewycky21cc4462009-04-04 07:22:01 +0000[diff] [blame]2331
2332 <dt><b>Metadata node</b></dt>
Nick Lewycky1e8c7a62009-05-30 16:08:30 +0000[diff] [blame]2333 <dd>A metadata node is a structure-like constant with
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2334 <a href="#t_metadata">metadata type</a>. For example: "<tt>metadata !{
2335 i32 0, metadata !"test" }</tt>". Unlike other constants that are meant to
2336 be interpreted as part of the instruction stream, metadata is a place to
2337 attach additional information such as debug info.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2338</dl>
2339
2340</div>
2341
2342<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2343<h3>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2344 <a name="globalconstants">Global Variable and Function Addresses</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2345</h3>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2346
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2347<div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2348
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2349<p>The addresses of <a href="#globalvars">global variables</a>
2350 and <a href="#functionstructure">functions</a> are always implicitly valid
2351 (link-time) constants. These constants are explicitly referenced when
2352 the <a href="#identifiers">identifier for the global</a> is used and always
2353 have <a href="#t_pointer">pointer</a> type. For example, the following is a
2354 legal LLVM file:</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2355
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2356<pre class="doc_code">
Chris Lattnera18a4242007-06-06 18:28:13 +0000[diff] [blame]2357@X = global i32 17
2358@Y = global i32 42
2359@Z = global [2 x i32*] [ i32* @X, i32* @Y ]
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2360</pre>
2361
2362</div>
2363
2364<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2365<h3>
2366 <a name="undefvalues">Undefined Values</a>
2367</h3>
2368
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2369<div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2370
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2371<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]2372 indicates that the user of the value may receive an unspecified bit-pattern.
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]2373 Undefined values may be of any type (other than '<tt>label</tt>'
2374 or '<tt>void</tt>') and be used anywhere a constant is permitted.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2375
Chris Lattnerc608cb12009-09-11 01:49:31 +0000[diff] [blame]2376<p>Undefined values are useful because they indicate to the compiler that the
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2377 program is well defined no matter what value is used. This gives the
2378 compiler more freedom to optimize. Here are some examples of (potentially
2379 surprising) transformations that are valid (in pseudo IR):</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2380
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2381
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2382<pre class="doc_code">
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2383 %A = add %X, undef
2384 %B = sub %X, undef
2385 %C = xor %X, undef
2386Safe:
2387 %A = undef
2388 %B = undef
2389 %C = undef
2390</pre>
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2391
2392<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]2393 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]2394
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2395<pre class="doc_code">
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2396 %A = or %X, undef
2397 %B = and %X, undef
2398Safe:
2399 %A = -1
2400 %B = 0
2401Unsafe:
2402 %A = undef
2403 %B = undef
2404</pre>
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2405
2406<p>These logical operations have bits that are not always affected by the input.
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]2407 For example, if <tt>%X</tt> has a zero bit, then the output of the
2408 '<tt>and</tt>' operation will always be a zero for that bit, no matter what
2409 the corresponding bit from the '<tt>undef</tt>' is. As such, it is unsafe to
2410 optimize or assume that the result of the '<tt>and</tt>' is '<tt>undef</tt>'.
2411 However, it is safe to assume that all bits of the '<tt>undef</tt>' could be
2412 0, and optimize the '<tt>and</tt>' to 0. Likewise, it is safe to assume that
2413 all the bits of the '<tt>undef</tt>' operand to the '<tt>or</tt>' could be
2414 set, allowing the '<tt>or</tt>' to be folded to -1.</p>
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2415
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2416<pre class="doc_code">
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2417 %A = select undef, %X, %Y
2418 %B = select undef, 42, %Y
2419 %C = select %X, %Y, undef
2420Safe:
2421 %A = %X (or %Y)
2422 %B = 42 (or %Y)
2423 %C = %Y
2424Unsafe:
2425 %A = undef
2426 %B = undef
2427 %C = undef
2428</pre>
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2429
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]2430<p>This set of examples shows that undefined '<tt>select</tt>' (and conditional
2431 branch) conditions can go <em>either way</em>, but they have to come from one
2432 of the two operands. In the <tt>%A</tt> example, if <tt>%X</tt> and
2433 <tt>%Y</tt> were both known to have a clear low bit, then <tt>%A</tt> would
2434 have to have a cleared low bit. However, in the <tt>%C</tt> example, the
2435 optimizer is allowed to assume that the '<tt>undef</tt>' operand could be the
2436 same as <tt>%Y</tt>, allowing the whole '<tt>select</tt>' to be
2437 eliminated.</p>
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2438
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2439<pre class="doc_code">
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2440 %A = xor undef, undef
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]2441
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2442 %B = undef
2443 %C = xor %B, %B
2444
2445 %D = undef
2446 %E = icmp lt %D, 4
2447 %F = icmp gte %D, 4
2448
2449Safe:
2450 %A = undef
2451 %B = undef
2452 %C = undef
2453 %D = undef
2454 %E = undef
2455 %F = undef
2456</pre>
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2457
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]2458<p>This example points out that two '<tt>undef</tt>' operands are not
2459 necessarily the same. This can be surprising to people (and also matches C
2460 semantics) where they assume that "<tt>X^X</tt>" is always zero, even
2461 if <tt>X</tt> is undefined. This isn't true for a number of reasons, but the
2462 short answer is that an '<tt>undef</tt>' "variable" can arbitrarily change
2463 its value over its "live range". This is true because the variable doesn't
2464 actually <em>have a live range</em>. Instead, the value is logically read
2465 from arbitrary registers that happen to be around when needed, so the value
2466 is not necessarily consistent over time. In fact, <tt>%A</tt> and <tt>%C</tt>
2467 need to have the same semantics or the core LLVM "replace all uses with"
2468 concept would not hold.</p>
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2469
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2470<pre class="doc_code">
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2471 %A = fdiv undef, %X
2472 %B = fdiv %X, undef
2473Safe:
2474 %A = undef
2475b: unreachable
2476</pre>
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2477
2478<p>These examples show the crucial difference between an <em>undefined
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]2479 value</em> and <em>undefined behavior</em>. An undefined value (like
2480 '<tt>undef</tt>') is allowed to have an arbitrary bit-pattern. This means that
2481 the <tt>%A</tt> operation can be constant folded to '<tt>undef</tt>', because
2482 the '<tt>undef</tt>' could be an SNaN, and <tt>fdiv</tt> is not (currently)
2483 defined on SNaN's. However, in the second example, we can make a more
2484 aggressive assumption: because the <tt>undef</tt> is allowed to be an
2485 arbitrary value, we are allowed to assume that it could be zero. Since a
2486 divide by zero has <em>undefined behavior</em>, we are allowed to assume that
2487 the operation does not execute at all. This allows us to delete the divide and
2488 all code after it. Because the undefined operation "can't happen", the
2489 optimizer can assume that it occurs in dead code.</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]2490
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2491<pre class="doc_code">
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2492a: store undef -> %X
2493b: store %X -> undef
2494Safe:
2495a: &lt;deleted&gt;
2496b: unreachable
2497</pre>
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2498
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]2499<p>These examples reiterate the <tt>fdiv</tt> example: a store <em>of</em> an
2500 undefined value can be assumed to not have any effect; we can assume that the
2501 value is overwritten with bits that happen to match what was already there.
2502 However, a store <em>to</em> an undefined location could clobber arbitrary
2503 memory, therefore, it has undefined behavior.</p>
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2504
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2505</div>
2506
2507<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2508<h3>
Dan Gohmanbfb056d2011-12-06 03:18:47 +0000[diff] [blame]2509 <a name="poisonvalues">Poison Values</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2510</h3>
2511
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2512<div>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]2513
Dan Gohmanbfb056d2011-12-06 03:18:47 +0000[diff] [blame]2514<p>Poison values are similar to <a href="#undefvalues">undef values</a>, however
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]2515 instead of representing an unspecified bit pattern, they represent the
2516 fact that an instruction or constant expression which cannot evoke side
2517 effects has nevertheless detected a condition which results in undefined
Dan Gohmanc68ce062010-04-26 20:21:21 +0000[diff] [blame]2518 behavior.</p>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]2519
Dan Gohmanbfb056d2011-12-06 03:18:47 +0000[diff] [blame]2520<p>There is currently no way of representing a poison value in the IR; they
Dan Gohman855abed2010-05-03 14:51:43 +0000[diff] [blame]2521 only exist when produced by operations such as
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2522 <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]2523
Dan Gohmanbfb056d2011-12-06 03:18:47 +0000[diff] [blame]2524<p>Poison value behavior is defined in terms of value <i>dependence</i>:</p>
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2525
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2526<ul>
2527<li>Values other than <a href="#i_phi"><tt>phi</tt></a> nodes depend on
2528 their operands.</li>
2529
2530<li><a href="#i_phi"><tt>Phi</tt></a> nodes depend on the operand corresponding
2531 to their dynamic predecessor basic block.</li>
2532
2533<li>Function arguments depend on the corresponding actual argument values in
2534 the dynamic callers of their functions.</li>
2535
2536<li><a href="#i_call"><tt>Call</tt></a> instructions depend on the
2537 <a href="#i_ret"><tt>ret</tt></a> instructions that dynamically transfer
2538 control back to them.</li>
2539
Dan Gohmanb5328162010-05-03 14:55:22 +0000[diff] [blame]2540<li><a href="#i_invoke"><tt>Invoke</tt></a> instructions depend on the
2541 <a href="#i_ret"><tt>ret</tt></a>, <a href="#i_unwind"><tt>unwind</tt></a>,
2542 or exception-throwing call instructions that dynamically transfer control
2543 back to them.</li>
2544
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2545<li>Non-volatile loads and stores depend on the most recent stores to all of the
2546 referenced memory addresses, following the order in the IR
2547 (including loads and stores implied by intrinsics such as
2548 <a href="#int_memcpy"><tt>@llvm.memcpy</tt></a>.)</li>
2549
Dan Gohman7c24ff12010-05-03 14:59:34 +0000[diff] [blame]2550<!-- TODO: In the case of multiple threads, this only applies if the store
2551 "happens-before" the load or store. -->
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2552
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2553<!-- TODO: floating-point exception state -->
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2554
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2555<li>An instruction with externally visible side effects depends on the most
2556 recent preceding instruction with externally visible side effects, following
Dan Gohmanff70fe42010-07-06 15:26:33 +0000[diff] [blame]2557 the order in the IR. (This includes
2558 <a href="#volatile">volatile operations</a>.)</li>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]2559
Dan Gohmanb5328162010-05-03 14:55:22 +0000[diff] [blame]2560<li>An instruction <i>control-depends</i> on a
2561 <a href="#terminators">terminator instruction</a>
2562 if the terminator instruction has multiple successors and the instruction
2563 is always executed when control transfers to one of the successors, and
Chris Lattner7a2bdde2011-04-15 05:18:47 +0000[diff] [blame]2564 may not be executed when control is transferred to another.</li>
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2565
Dan Gohmanca4cac42011-04-12 23:05:59 +0000[diff] [blame]2566<li>Additionally, an instruction also <i>control-depends</i> on a terminator
2567 instruction if the set of instructions it otherwise depends on would be
Chris Lattner7a2bdde2011-04-15 05:18:47 +0000[diff] [blame]2568 different if the terminator had transferred control to a different
Dan Gohmanca4cac42011-04-12 23:05:59 +0000[diff] [blame]2569 successor.</li>
2570
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2571<li>Dependence is transitive.</li>
2572
2573</ul>
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2574
Dan Gohmanbfb056d2011-12-06 03:18:47 +0000[diff] [blame]2575<p>Whenever a poison value is generated, all values which depend on it evaluate
2576 to poison. If they have side effects, they evoke their side effects as if each
2577 operand with a poison value were undef. If they have externally-visible side
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2578 effects, the behavior is undefined.</p>
2579
2580<p>Here are some examples:</p>
Dan Gohmanc30f6e12010-04-26 20:54:53 +0000[diff] [blame]2581
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2582<pre class="doc_code">
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2583entry:
Dan Gohmanbfb056d2011-12-06 03:18:47 +0000[diff] [blame]2584 %poison = sub nuw i32 0, 1 ; Results in a poison value.
Dan Gohman5cdc51e2011-12-06 03:31:14 +0000[diff] [blame^]2585 %still_poison = and i32 %poison, 0 ; Whereas (and i32 undef, 0) would return 0.
Dan Gohmanbfb056d2011-12-06 03:18:47 +0000[diff] [blame]2586 %poison_yet_again = getelementptr i32* @h, i32 %still_poison
2587 store i32 0, i32* %poison_yet_again ; undefined behavior
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2588
Dan Gohman5cdc51e2011-12-06 03:31:14 +0000[diff] [blame^]2589 store i32 %poison, i32* @g ; Poison value conceptually stored to memory.
Dan Gohmanbfb056d2011-12-06 03:18:47 +0000[diff] [blame]2590 %poison2 = load i32* @g ; Returns a poison value, not just undef.
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2591
Dan Gohmanbfb056d2011-12-06 03:18:47 +0000[diff] [blame]2592 store volatile i32 %poison, i32* @g ; External observation; undefined behavior.
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2593
2594 %narrowaddr = bitcast i32* @g to i16*
2595 %wideaddr = bitcast i32* @g to i64*
Dan Gohmanbfb056d2011-12-06 03:18:47 +0000[diff] [blame]2596 %poison3 = load i16* %narrowaddr ; Returns a poison value.
2597 %poison4 = load i64* %wideaddr ; Returns a poison value.
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2598
Dan Gohman5cdc51e2011-12-06 03:31:14 +0000[diff] [blame^]2599 %cmp = icmp slt i32 %poison, 0 ; Returns a poison value.
2600 br i1 %cmp, label %true, label %end ; Branch to either destination.
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2601
2602true:
Dan Gohman5cdc51e2011-12-06 03:31:14 +0000[diff] [blame^]2603 store volatile i32 0, i32* @g ; This is control-dependent on %cmp, so
2604 ; it has undefined behavior.
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2605 br label %end
2606
2607end:
2608 %p = phi i32 [ 0, %entry ], [ 1, %true ]
Dan Gohman5cdc51e2011-12-06 03:31:14 +0000[diff] [blame^]2609 ; Both edges into this PHI are
2610 ; control-dependent on %cmp, so this
2611 ; always results in a poison value.
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2612
Dan Gohman5cdc51e2011-12-06 03:31:14 +0000[diff] [blame^]2613 store volatile i32 0, i32* @g ; This would depend on the store in %true
2614 ; if %cmp is true, or the store in %entry
2615 ; otherwise, so this is undefined behavior.
Dan Gohmanca4cac42011-04-12 23:05:59 +0000[diff] [blame]2616
Nick Lewycky64f9fb12011-05-16 19:29:30 +0000[diff] [blame]2617 br i1 %cmp, label %second_true, label %second_end
Dan Gohman5cdc51e2011-12-06 03:31:14 +0000[diff] [blame^]2618 ; The same branch again, but this time the
2619 ; true block doesn't have side effects.
Dan Gohmanca4cac42011-04-12 23:05:59 +0000[diff] [blame]2620
2621second_true:
2622 ; No side effects!
Nick Lewycky64f9fb12011-05-16 19:29:30 +0000[diff] [blame]2623 ret void
Dan Gohmanca4cac42011-04-12 23:05:59 +0000[diff] [blame]2624
2625second_end:
Dan Gohman5cdc51e2011-12-06 03:31:14 +0000[diff] [blame^]2626 store volatile i32 0, i32* @g ; This time, the instruction always depends
2627 ; on the store in %end. Also, it is
2628 ; control-equivalent to %end, so this is
2629 ; well-defined (again, ignoring earlier
2630 ; undefined behavior in this example).
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2631</pre>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]2632
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]2633</div>
2634
2635<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2636<h3>
2637 <a name="blockaddress">Addresses of Basic Blocks</a>
2638</h3>
2639
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2640<div>
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]2641
Chris Lattnercdfc9402009-11-01 01:27:45 +0000[diff] [blame]2642<p><b><tt>blockaddress(@function, %block)</tt></b></p>
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]2643
2644<p>The '<tt>blockaddress</tt>' constant computes the address of the specified
Chris Lattner2dfdf2a2009-10-27 21:49:40 +0000[diff] [blame]2645 basic block in the specified function, and always has an i8* type. Taking
Chris Lattnercdfc9402009-11-01 01:27:45 +0000[diff] [blame]2646 the address of the entry block is illegal.</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]2647
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]2648<p>This value only has defined behavior when used as an operand to the
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]2649 '<a href="#i_indirectbr"><tt>indirectbr</tt></a>' instruction, or for
2650 comparisons against null. Pointer equality tests between labels addresses
2651 results in undefined behavior &mdash; though, again, comparison against null
2652 is ok, and no label is equal to the null pointer. This may be passed around
2653 as an opaque pointer sized value as long as the bits are not inspected. This
2654 allows <tt>ptrtoint</tt> and arithmetic to be performed on these values so
2655 long as the original value is reconstituted before the <tt>indirectbr</tt>
2656 instruction.</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]2657
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]2658<p>Finally, some targets may provide defined semantics when using the value as
2659 the operand to an inline assembly, but that is target specific.</p>
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]2660
2661</div>
2662
2663
2664<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2665<h3>
2666 <a name="constantexprs">Constant Expressions</a>
2667</h3>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2668
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2669<div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2670
2671<p>Constant expressions are used to allow expressions involving other constants
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2672 to be used as constants. Constant expressions may be of
2673 any <a href="#t_firstclass">first class</a> type and may involve any LLVM
2674 operation that does not have side effects (e.g. load and call are not
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]2675 supported). The following is the syntax for constant expressions:</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2676
2677<dl>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2678 <dt><b><tt>trunc (CST to TYPE)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2679 <dd>Truncate a constant to another type. The bit size of CST must be larger
2680 than the bit size of TYPE. Both types must be integers.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2681
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2682 <dt><b><tt>zext (CST to TYPE)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2683 <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]2684 smaller than the bit size of TYPE. Both types must be integers.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2685
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2686 <dt><b><tt>sext (CST to TYPE)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2687 <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]2688 smaller than the bit size of TYPE. Both types must be integers.</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>fptrunc (CST to TYPE)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2691 <dd>Truncate a floating point constant to another floating point type. The
2692 size of CST must be larger than the size of TYPE. Both types must be
2693 floating point.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2694
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2695 <dt><b><tt>fpext (CST to TYPE)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2696 <dd>Floating point extend a constant to another type. The size of CST must be
2697 smaller or equal to the size of TYPE. Both types must be floating
2698 point.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2699
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2700 <dt><b><tt>fptoui (CST to TYPE)</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2701 <dd>Convert a floating point constant to the corresponding unsigned integer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2702 constant. TYPE must be a scalar or vector integer type. CST must be of
2703 scalar or vector floating point type. Both CST and TYPE must be scalars,
2704 or vectors of the same number of elements. If the value won't fit in the
2705 integer type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2706
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2707 <dt><b><tt>fptosi (CST to TYPE)</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2708 <dd>Convert a floating point constant to the corresponding signed integer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2709 constant. TYPE must be a scalar or vector integer type. CST must be of
2710 scalar or vector floating point type. Both CST and TYPE must be scalars,
2711 or vectors of the same number of elements. If the value won't fit in the
2712 integer type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2713
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2714 <dt><b><tt>uitofp (CST to TYPE)</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2715 <dd>Convert an unsigned integer constant to the corresponding floating point
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2716 constant. TYPE must be a scalar or vector floating point type. CST must be
2717 of scalar or vector integer type. Both CST and TYPE must be scalars, or
2718 vectors of the same number of elements. If the value won't fit in the
2719 floating point type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2720
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2721 <dt><b><tt>sitofp (CST to TYPE)</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2722 <dd>Convert a signed integer constant to the corresponding floating point
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2723 constant. TYPE must be a scalar or vector floating point type. CST must be
2724 of scalar or vector integer type. Both CST and TYPE must be scalars, or
2725 vectors of the same number of elements. If the value won't fit in the
2726 floating point type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2727
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2728 <dt><b><tt>ptrtoint (CST to TYPE)</tt></b></dt>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]2729 <dd>Convert a pointer typed constant to the corresponding integer constant
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2730 <tt>TYPE</tt> must be an integer type. <tt>CST</tt> must be of pointer
2731 type. The <tt>CST</tt> value is zero extended, truncated, or unchanged to
2732 make it fit in <tt>TYPE</tt>.</dd>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]2733
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2734 <dt><b><tt>inttoptr (CST to TYPE)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2735 <dd>Convert a integer constant to a pointer constant. TYPE must be a pointer
2736 type. CST must be of integer type. The CST value is zero extended,
2737 truncated, or unchanged to make it fit in a pointer size. This one is
2738 <i>really</i> dangerous!</dd>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]2739
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2740 <dt><b><tt>bitcast (CST to TYPE)</tt></b></dt>
Chris Lattner03bbad62009-02-28 18:27:03 +0000[diff] [blame]2741 <dd>Convert a constant, CST, to another TYPE. The constraints of the operands
2742 are the same as those for the <a href="#i_bitcast">bitcast
2743 instruction</a>.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2744
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2745 <dt><b><tt>getelementptr (CSTPTR, IDX0, IDX1, ...)</tt></b></dt>
2746 <dt><b><tt>getelementptr inbounds (CSTPTR, IDX0, IDX1, ...)</tt></b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2747 <dd>Perform the <a href="#i_getelementptr">getelementptr operation</a> on
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2748 constants. As with the <a href="#i_getelementptr">getelementptr</a>
2749 instruction, the index list may have zero or more indexes, which are
2750 required to make sense for the type of "CSTPTR".</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2751
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2752 <dt><b><tt>select (COND, VAL1, VAL2)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2753 <dd>Perform the <a href="#i_select">select operation</a> on constants.</dd>
Reid Spencer01c42592006-12-04 19:23:19 +0000[diff] [blame]2754
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2755 <dt><b><tt>icmp COND (VAL1, VAL2)</tt></b></dt>
Reid Spencer01c42592006-12-04 19:23:19 +0000[diff] [blame]2756 <dd>Performs the <a href="#i_icmp">icmp operation</a> on constants.</dd>
2757
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2758 <dt><b><tt>fcmp COND (VAL1, VAL2)</tt></b></dt>
Reid Spencer01c42592006-12-04 19:23:19 +0000[diff] [blame]2759 <dd>Performs the <a href="#i_fcmp">fcmp operation</a> on constants.</dd>
Robert Bocchino9fbe1452006-01-10 19:31:34 +0000[diff] [blame]2760
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2761 <dt><b><tt>extractelement (VAL, IDX)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2762 <dd>Perform the <a href="#i_extractelement">extractelement operation</a> on
2763 constants.</dd>
Robert Bocchino9fbe1452006-01-10 19:31:34 +0000[diff] [blame]2764
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2765 <dt><b><tt>insertelement (VAL, ELT, IDX)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2766 <dd>Perform the <a href="#i_insertelement">insertelement operation</a> on
2767 constants.</dd>
Chris Lattnerc1989542006-04-08 00:13:41 +0000[diff] [blame]2768
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2769 <dt><b><tt>shufflevector (VEC1, VEC2, IDXMASK)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2770 <dd>Perform the <a href="#i_shufflevector">shufflevector operation</a> on
2771 constants.</dd>
Chris Lattnerc1989542006-04-08 00:13:41 +0000[diff] [blame]2772
Nick Lewycky9e130ce2010-05-29 06:44:15 +0000[diff] [blame]2773 <dt><b><tt>extractvalue (VAL, IDX0, IDX1, ...)</tt></b></dt>
2774 <dd>Perform the <a href="#i_extractvalue">extractvalue operation</a> on
2775 constants. The index list is interpreted in a similar manner as indices in
2776 a '<a href="#i_getelementptr">getelementptr</a>' operation. At least one
2777 index value must be specified.</dd>
2778
2779 <dt><b><tt>insertvalue (VAL, ELT, IDX0, IDX1, ...)</tt></b></dt>
2780 <dd>Perform the <a href="#i_insertvalue">insertvalue operation</a> on
2781 constants. The index list is interpreted in a similar manner as indices in
2782 a '<a href="#i_getelementptr">getelementptr</a>' operation. At least one
2783 index value must be specified.</dd>
2784
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2785 <dt><b><tt>OPCODE (LHS, RHS)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2786 <dd>Perform the specified operation of the LHS and RHS constants. OPCODE may
2787 be any of the <a href="#binaryops">binary</a>
2788 or <a href="#bitwiseops">bitwise binary</a> operations. The constraints
2789 on operands are the same as those for the corresponding instruction
2790 (e.g. no bitwise operations on floating point values are allowed).</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2791</dl>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2792
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2793</div>
Chris Lattner9ee5d222004-03-08 16:49:10 +0000[diff] [blame]2794
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2795</div>
2796
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2797<!-- *********************************************************************** -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2798<h2><a name="othervalues">Other Values</a></h2>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2799<!-- *********************************************************************** -->
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2800<div>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2801<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2802<h3>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2803<a name="inlineasm">Inline Assembler Expressions</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2804</h3>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2805
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2806<div>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2807
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2808<p>LLVM supports inline assembler expressions (as opposed
Bill Wendlingaee0f452011-11-30 21:52:43 +0000[diff] [blame]2809 to <a href="#moduleasm">Module-Level Inline Assembly</a>) through the use of
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2810 a special value. This value represents the inline assembler as a string
2811 (containing the instructions to emit), a list of operand constraints (stored
Dale Johannesen09fed252009-10-13 21:56:55 +0000[diff] [blame]2812 as a string), a flag that indicates whether or not the inline asm
Dale Johannesen8ba2d5b2009-10-21 23:28:00 +0000[diff] [blame]2813 expression has side effects, and a flag indicating whether the function
2814 containing the asm needs to align its stack conservatively. An example
2815 inline assembler expression is:</p>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2816
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2817<pre class="doc_code">
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2818i32 (i32) asm "bswap $0", "=r,r"
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2819</pre>
2820
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2821<p>Inline assembler expressions may <b>only</b> be used as the callee operand of
2822 a <a href="#i_call"><tt>call</tt> instruction</a>. Thus, typically we
2823 have:</p>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2824
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2825<pre class="doc_code">
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2826%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]2827</pre>
2828
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2829<p>Inline asms with side effects not visible in the constraint list must be
2830 marked as having side effects. This is done through the use of the
2831 '<tt>sideeffect</tt>' keyword, like so:</p>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2832
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2833<pre class="doc_code">
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2834call void asm sideeffect "eieio", ""()
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2835</pre>
2836
Dale Johannesen8ba2d5b2009-10-21 23:28:00 +0000[diff] [blame]2837<p>In some cases inline asms will contain code that will not work unless the
2838 stack is aligned in some way, such as calls or SSE instructions on x86,
2839 yet will not contain code that does that alignment within the asm.
2840 The compiler should make conservative assumptions about what the asm might
2841 contain and should generate its usual stack alignment code in the prologue
2842 if the '<tt>alignstack</tt>' keyword is present:</p>
Dale Johannesen09fed252009-10-13 21:56:55 +0000[diff] [blame]2843
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2844<pre class="doc_code">
Dale Johannesen8ba2d5b2009-10-21 23:28:00 +0000[diff] [blame]2845call void asm alignstack "eieio", ""()
Dale Johannesen09fed252009-10-13 21:56:55 +0000[diff] [blame]2846</pre>
Dale Johannesen09fed252009-10-13 21:56:55 +0000[diff] [blame]2847
2848<p>If both keywords appear the '<tt>sideeffect</tt>' keyword must come
2849 first.</p>
2850
Bill Wendlingaee0f452011-11-30 21:52:43 +0000[diff] [blame]2851<!--
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2852<p>TODO: The format of the asm and constraints string still need to be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2853 documented here. Constraints on what can be done (e.g. duplication, moving,
2854 etc need to be documented). This is probably best done by reference to
2855 another document that covers inline asm from a holistic perspective.</p>
Bill Wendlingaee0f452011-11-30 21:52:43 +0000[diff] [blame]2856 -->
Chris Lattnercf9a4152010-04-07 05:38:05 +0000[diff] [blame]2857
Bill Wendlingaee0f452011-11-30 21:52:43 +0000[diff] [blame]2858<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2859<h4>
Bill Wendlingaee0f452011-11-30 21:52:43 +0000[diff] [blame]2860 <a name="inlineasm_md">Inline Asm Metadata</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2861</h4>
Chris Lattnercf9a4152010-04-07 05:38:05 +0000[diff] [blame]2862
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2863<div>
Chris Lattnercf9a4152010-04-07 05:38:05 +0000[diff] [blame]2864
Bill Wendlingaee0f452011-11-30 21:52:43 +0000[diff] [blame]2865<p>The call instructions that wrap inline asm nodes may have a
2866 "<tt>!srcloc</tt>" MDNode attached to it that contains a list of constant
2867 integers. If present, the code generator will use the integer as the
2868 location cookie value when report errors through the <tt>LLVMContext</tt>
2869 error reporting mechanisms. This allows a front-end to correlate backend
2870 errors that occur with inline asm back to the source code that produced it.
2871 For example:</p>
Chris Lattnercf9a4152010-04-07 05:38:05 +0000[diff] [blame]2872
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2873<pre class="doc_code">
Chris Lattnercf9a4152010-04-07 05:38:05 +0000[diff] [blame]2874call void asm sideeffect "something bad", ""()<b>, !srcloc !42</b>
2875...
2876!42 = !{ i32 1234567 }
2877</pre>
Chris Lattnercf9a4152010-04-07 05:38:05 +0000[diff] [blame]2878
2879<p>It is up to the front-end to make sense of the magic numbers it places in the
Bill Wendlingaee0f452011-11-30 21:52:43 +0000[diff] [blame]2880 IR. If the MDNode contains multiple constants, the code generator will use
Chris Lattnerce1b9ad2010-11-17 08:20:42 +0000[diff] [blame]2881 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]2882
2883</div>
2884
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2885</div>
2886
Chris Lattnere6a5ddd2010-01-15 21:50:19 +0000[diff] [blame]2887<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2888<h3>
2889 <a name="metadata">Metadata Nodes and Metadata Strings</a>
2890</h3>
Chris Lattnere6a5ddd2010-01-15 21:50:19 +0000[diff] [blame]2891
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2892<div>
Chris Lattnere6a5ddd2010-01-15 21:50:19 +0000[diff] [blame]2893
2894<p>LLVM IR allows metadata to be attached to instructions in the program that
2895 can convey extra information about the code to the optimizers and code
2896 generator. One example application of metadata is source-level debug
2897 information. There are two metadata primitives: strings and nodes. All
2898 metadata has the <tt>metadata</tt> type and is identified in syntax by a
2899 preceding exclamation point ('<tt>!</tt>').</p>
2900
2901<p>A metadata string is a string surrounded by double quotes. It can contain
Bill Wendlingf6cc4c22011-11-30 21:43:43 +0000[diff] [blame]2902 any character by escaping non-printable characters with "<tt>\xx</tt>" where
2903 "<tt>xx</tt>" is the two digit hex code. For example:
2904 "<tt>!"test\00"</tt>".</p>
Chris Lattnere6a5ddd2010-01-15 21:50:19 +0000[diff] [blame]2905
2906<p>Metadata nodes are represented with notation similar to structure constants
2907 (a comma separated list of elements, surrounded by braces and preceded by an
Bill Wendlingf6cc4c22011-11-30 21:43:43 +0000[diff] [blame]2908 exclamation point). Metadata nodes can have any values as their operand. For
2909 example:</p>
2910
2911<div class="doc_code">
2912<pre>
2913!{ metadata !"test\00", i32 10}
2914</pre>
2915</div>
Chris Lattnere6a5ddd2010-01-15 21:50:19 +0000[diff] [blame]2916
2917<p>A <a href="#namedmetadatastructure">named metadata</a> is a collection of
2918 metadata nodes, which can be looked up in the module symbol table. For
Bill Wendlingf6cc4c22011-11-30 21:43:43 +0000[diff] [blame]2919 example:</p>
2920
2921<div class="doc_code">
2922<pre>
2923!foo = metadata !{!4, !3}
2924</pre>
2925</div>
Chris Lattnere6a5ddd2010-01-15 21:50:19 +0000[diff] [blame]2926
Devang Patele1d50cd2010-03-04 23:44:48 +0000[diff] [blame]2927<p>Metadata can be used as function arguments. Here <tt>llvm.dbg.value</tt>
Bill Wendlingf6cc4c22011-11-30 21:43:43 +0000[diff] [blame]2928 function is using two metadata arguments:</p>
Devang Patele1d50cd2010-03-04 23:44:48 +0000[diff] [blame]2929
Bill Wendling9ff5de92011-03-02 02:17:11 +0000[diff] [blame]2930<div class="doc_code">
2931<pre>
2932call void @llvm.dbg.value(metadata !24, i64 0, metadata !25)
2933</pre>
2934</div>
Devang Patele1d50cd2010-03-04 23:44:48 +0000[diff] [blame]2935
2936<p>Metadata can be attached with an instruction. Here metadata <tt>!21</tt> is
Bill Wendlingf6cc4c22011-11-30 21:43:43 +0000[diff] [blame]2937 attached to the <tt>add</tt> instruction using the <tt>!dbg</tt>
2938 identifier:</p>
Devang Patele1d50cd2010-03-04 23:44:48 +0000[diff] [blame]2939
Bill Wendling9ff5de92011-03-02 02:17:11 +0000[diff] [blame]2940<div class="doc_code">
2941<pre>
2942%indvar.next = add i64 %indvar, 1, !dbg !21
2943</pre>
2944</div>
2945
Peter Collingbourne249d9532011-10-27 19:19:07 +0000[diff] [blame]2946<p>More information about specific metadata nodes recognized by the optimizers
2947 and code generator is found below.</p>
2948
Bill Wendlingf6cc4c22011-11-30 21:43:43 +0000[diff] [blame]2949<!-- _______________________________________________________________________ -->
Peter Collingbourne249d9532011-10-27 19:19:07 +0000[diff] [blame]2950<h4>
2951 <a name="tbaa">'<tt>tbaa</tt>' Metadata</a>
2952</h4>
2953
2954<div>
2955
2956<p>In LLVM IR, memory does not have types, so LLVM's own type system is not
2957 suitable for doing TBAA. Instead, metadata is added to the IR to describe
2958 a type system of a higher level language. This can be used to implement
2959 typical C/C++ TBAA, but it can also be used to implement custom alias
2960 analysis behavior for other languages.</p>
2961
2962<p>The current metadata format is very simple. TBAA metadata nodes have up to
2963 three fields, e.g.:</p>
2964
2965<div class="doc_code">
2966<pre>
2967!0 = metadata !{ metadata !"an example type tree" }
2968!1 = metadata !{ metadata !"int", metadata !0 }
2969!2 = metadata !{ metadata !"float", metadata !0 }
2970!3 = metadata !{ metadata !"const float", metadata !2, i64 1 }
2971</pre>
2972</div>
2973
2974<p>The first field is an identity field. It can be any value, usually
2975 a metadata string, which uniquely identifies the type. The most important
2976 name in the tree is the name of the root node. Two trees with
2977 different root node names are entirely disjoint, even if they
2978 have leaves with common names.</p>
2979
2980<p>The second field identifies the type's parent node in the tree, or
2981 is null or omitted for a root node. A type is considered to alias
2982 all of its descendants and all of its ancestors in the tree. Also,
2983 a type is considered to alias all types in other trees, so that
2984 bitcode produced from multiple front-ends is handled conservatively.</p>
2985
2986<p>If the third field is present, it's an integer which if equal to 1
2987 indicates that the type is "constant" (meaning
2988 <tt>pointsToConstantMemory</tt> should return true; see
2989 <a href="AliasAnalysis.html#OtherItfs">other useful
2990 <tt>AliasAnalysis</tt> methods</a>).</p>
2991
2992</div>
2993
Bill Wendlingf6cc4c22011-11-30 21:43:43 +0000[diff] [blame]2994<!-- _______________________________________________________________________ -->
Peter Collingbourne999f90b2011-10-27 19:19:14 +0000[diff] [blame]2995<h4>
2996 <a name="fpaccuracy">'<tt>fpaccuracy</tt>' Metadata</a>
2997</h4>
2998
2999<div>
3000
3001<p><tt>fpaccuracy</tt> metadata may be attached to any instruction of floating
3002 point type. It expresses the maximum relative error of the result of
3003 that instruction, in ULPs. ULP is defined as follows:</p>
3004
Bill Wendling0656e252011-11-09 19:33:56 +0000[diff] [blame]3005<blockquote>
3006
3007<p>If <tt>x</tt> is a real number that lies between two finite consecutive
3008 floating-point numbers <tt>a</tt> and <tt>b</tt>, without being equal to one
3009 of them, then <tt>ulp(x) = |b - a|</tt>, otherwise <tt>ulp(x)</tt> is the
3010 distance between the two non-equal finite floating-point numbers nearest
3011 <tt>x</tt>. Moreover, <tt>ulp(NaN)</tt> is <tt>NaN</tt>.</p>
3012
3013</blockquote>
Peter Collingbourne999f90b2011-10-27 19:19:14 +0000[diff] [blame]3014
3015<p>The maximum relative error may be any rational number. The metadata node
3016 shall consist of a pair of unsigned integers respectively representing
3017 the numerator and denominator. For example, 2.5 ULP:</p>
3018
3019<div class="doc_code">
3020<pre>
3021!0 = metadata !{ i32 5, i32 2 }
3022</pre>
3023</div>
3024
3025</div>
3026
Chris Lattnere6a5ddd2010-01-15 21:50:19 +0000[diff] [blame]3027</div>
3028
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3029</div>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3030
3031<!-- *********************************************************************** -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3032<h2>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3033 <a name="intrinsic_globals">Intrinsic Global Variables</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3034</h2>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3035<!-- *********************************************************************** -->
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3036<div>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3037<p>LLVM has a number of "magic" global variables that contain data that affect
3038code generation or other IR semantics. These are documented here. All globals
Chris Lattner401e10c2009-07-20 06:14:25 +0000[diff] [blame]3039of this sort should have a section specified as "<tt>llvm.metadata</tt>". This
3040section and all globals that start with "<tt>llvm.</tt>" are reserved for use
3041by LLVM.</p>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3042
3043<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3044<h3>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3045<a name="intg_used">The '<tt>llvm.used</tt>' Global Variable</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3046</h3>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3047
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3048<div>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3049
3050<p>The <tt>@llvm.used</tt> global is an array with i8* element type which has <a
3051href="#linkage_appending">appending linkage</a>. This array contains a list of
3052pointers to global variables and functions which may optionally have a pointer
3053cast formed of bitcast or getelementptr. For example, a legal use of it is:</p>
3054
Bill Wendling9ae75632011-11-08 00:32:45 +0000[diff] [blame]3055<div class="doc_code">
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3056<pre>
Bill Wendling9ae75632011-11-08 00:32:45 +0000[diff] [blame]3057@X = global i8 4
3058@Y = global i32 123
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3059
Bill Wendling9ae75632011-11-08 00:32:45 +0000[diff] [blame]3060@llvm.used = appending global [2 x i8*] [
3061 i8* @X,
3062 i8* bitcast (i32* @Y to i8*)
3063], section "llvm.metadata"
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3064</pre>
Bill Wendling9ae75632011-11-08 00:32:45 +0000[diff] [blame]3065</div>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3066
3067<p>If a global variable appears in the <tt>@llvm.used</tt> list, then the
Bill Wendling9ae75632011-11-08 00:32:45 +0000[diff] [blame]3068 compiler, assembler, and linker are required to treat the symbol as if there
3069 is a reference to the global that it cannot see. For example, if a variable
3070 has internal linkage and no references other than that from
3071 the <tt>@llvm.used</tt> list, it cannot be deleted. This is commonly used to
3072 represent references from inline asms and other things the compiler cannot
3073 "see", and corresponds to "<tt>attribute((used))</tt>" in GNU C.</p>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3074
3075<p>On some targets, the code generator must emit a directive to the assembler or
Bill Wendling9ae75632011-11-08 00:32:45 +0000[diff] [blame]3076 object file to prevent the assembler and linker from molesting the
3077 symbol.</p>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3078
3079</div>
3080
3081<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3082<h3>
3083 <a name="intg_compiler_used">
3084 The '<tt>llvm.compiler.used</tt>' Global Variable
3085 </a>
3086</h3>
Chris Lattner401e10c2009-07-20 06:14:25 +0000[diff] [blame]3087
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3088<div>
Chris Lattner401e10c2009-07-20 06:14:25 +0000[diff] [blame]3089
3090<p>The <tt>@llvm.compiler.used</tt> directive is the same as the
Bill Wendling9ae75632011-11-08 00:32:45 +0000[diff] [blame]3091 <tt>@llvm.used</tt> directive, except that it only prevents the compiler from
3092 touching the symbol. On targets that support it, this allows an intelligent
3093 linker to optimize references to the symbol without being impeded as it would
3094 be by <tt>@llvm.used</tt>.</p>
Chris Lattner401e10c2009-07-20 06:14:25 +0000[diff] [blame]3095
3096<p>This is a rare construct that should only be used in rare circumstances, and
Bill Wendling9ae75632011-11-08 00:32:45 +0000[diff] [blame]3097 should not be exposed to source languages.</p>
Chris Lattner401e10c2009-07-20 06:14:25 +0000[diff] [blame]3098
3099</div>
3100
3101<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3102<h3>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3103<a name="intg_global_ctors">The '<tt>llvm.global_ctors</tt>' Global Variable</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3104</h3>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3105
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3106<div>
Bill Wendling9ae75632011-11-08 00:32:45 +0000[diff] [blame]3107
3108<div class="doc_code">
David Chisnalle31e9962010-04-30 19:23:49 +0000[diff] [blame]3109<pre>
3110%0 = type { i32, void ()* }
David Chisnall27195a52010-04-30 19:27:35 +0000[diff] [blame]3111@llvm.global_ctors = appending global [1 x %0] [%0 { i32 65535, void ()* @ctor }]
David Chisnalle31e9962010-04-30 19:23:49 +0000[diff] [blame]3112</pre>
Bill Wendling9ae75632011-11-08 00:32:45 +0000[diff] [blame]3113</div>
3114
3115<p>The <tt>@llvm.global_ctors</tt> array contains a list of constructor
3116 functions and associated priorities. The functions referenced by this array
3117 will be called in ascending order of priority (i.e. lowest first) when the
3118 module is loaded. The order of functions with the same priority is not
3119 defined.</p>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3120
3121</div>
3122
3123<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3124<h3>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3125<a name="intg_global_dtors">The '<tt>llvm.global_dtors</tt>' Global Variable</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3126</h3>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3127
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3128<div>
Bill Wendling9ae75632011-11-08 00:32:45 +0000[diff] [blame]3129
3130<div class="doc_code">
David Chisnalle31e9962010-04-30 19:23:49 +0000[diff] [blame]3131<pre>
3132%0 = type { i32, void ()* }
David Chisnall27195a52010-04-30 19:27:35 +0000[diff] [blame]3133@llvm.global_dtors = appending global [1 x %0] [%0 { i32 65535, void ()* @dtor }]
David Chisnalle31e9962010-04-30 19:23:49 +0000[diff] [blame]3134</pre>
Bill Wendling9ae75632011-11-08 00:32:45 +0000[diff] [blame]3135</div>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3136
Bill Wendling9ae75632011-11-08 00:32:45 +0000[diff] [blame]3137<p>The <tt>@llvm.global_dtors</tt> array contains a list of destructor functions
3138 and associated priorities. The functions referenced by this array will be
3139 called in descending order of priority (i.e. highest first) when the module
3140 is loaded. The order of functions with the same priority is not defined.</p>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3141
3142</div>
3143
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3144</div>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3145
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]3146<!-- *********************************************************************** -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3147<h2><a name="instref">Instruction Reference</a></h2>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3148<!-- *********************************************************************** -->
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]3149
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3150<div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]3151
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3152<p>The LLVM instruction set consists of several different classifications of
3153 instructions: <a href="#terminators">terminator
3154 instructions</a>, <a href="#binaryops">binary instructions</a>,
3155 <a href="#bitwiseops">bitwise binary instructions</a>,
3156 <a href="#memoryops">memory instructions</a>, and
3157 <a href="#otherops">other instructions</a>.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]3158
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3159<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3160<h3>
3161 <a name="terminators">Terminator Instructions</a>
3162</h3>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]3163
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3164<div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]3165
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3166<p>As mentioned <a href="#functionstructure">previously</a>, every basic block
3167 in a program ends with a "Terminator" instruction, which indicates which
3168 block should be executed after the current block is finished. These
3169 terminator instructions typically yield a '<tt>void</tt>' value: they produce
3170 control flow, not values (the one exception being the
3171 '<a href="#i_invoke"><tt>invoke</tt></a>' instruction).</p>
3172
Chris Lattner6445ecb2011-08-02 20:29:13 +0000[diff] [blame]3173<p>The terminator instructions are:
3174 '<a href="#i_ret"><tt>ret</tt></a>',
3175 '<a href="#i_br"><tt>br</tt></a>',
3176 '<a href="#i_switch"><tt>switch</tt></a>',
3177 '<a href="#i_indirectbr"><tt>indirectbr</tt></a>',
3178 '<a href="#i_invoke"><tt>invoke</tt></a>',
3179 '<a href="#i_unwind"><tt>unwind</tt></a>',
3180 '<a href="#i_resume"><tt>resume</tt></a>', and
3181 '<a href="#i_unreachable"><tt>unreachable</tt></a>'.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]3182
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3183<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3184<h4>
3185 <a name="i_ret">'<tt>ret</tt>' Instruction</a>
3186</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3187
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3188<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3189
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3190<h5>Syntax:</h5>
Dan Gohmanb1e6b962008-10-04 19:00:07 +0000[diff] [blame]3191<pre>
3192 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]3193 ret void <i>; Return from void function</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3194</pre>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]3195
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3196<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3197<p>The '<tt>ret</tt>' instruction is used to return control flow (and optionally
3198 a value) from a function back to the caller.</p>
3199
3200<p>There are two forms of the '<tt>ret</tt>' instruction: one that returns a
3201 value and then causes control flow, and one that just causes control flow to
3202 occur.</p>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]3203
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3204<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3205<p>The '<tt>ret</tt>' instruction optionally accepts a single argument, the
3206 return value. The type of the return value must be a
3207 '<a href="#t_firstclass">first class</a>' type.</p>
Dan Gohmanb1e6b962008-10-04 19:00:07 +0000[diff] [blame]3208
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3209<p>A function is not <a href="#wellformed">well formed</a> if it it has a
3210 non-void return type and contains a '<tt>ret</tt>' instruction with no return
3211 value or a return value with a type that does not match its type, or if it
3212 has a void return type and contains a '<tt>ret</tt>' instruction with a
3213 return value.</p>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]3214
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3215<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3216<p>When the '<tt>ret</tt>' instruction is executed, control flow returns back to
3217 the calling function's context. If the caller is a
3218 "<a href="#i_call"><tt>call</tt></a>" instruction, execution continues at the
3219 instruction after the call. If the caller was an
3220 "<a href="#i_invoke"><tt>invoke</tt></a>" instruction, execution continues at
3221 the beginning of the "normal" destination block. If the instruction returns
3222 a value, that value shall set the call or invoke instruction's return
3223 value.</p>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]3224
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3225<h5>Example:</h5>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]3226<pre>
3227 ret i32 5 <i>; Return an integer value of 5</i>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]3228 ret void <i>; Return from a void function</i>
Bill Wendling0a4bbbf2009-02-28 22:12:54 +0000[diff] [blame]3229 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]3230</pre>
Dan Gohmanf3e60bd2009-01-12 23:12:39 +0000[diff] [blame]3231
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3232</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3233<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3234<h4>
3235 <a name="i_br">'<tt>br</tt>' Instruction</a>
3236</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3237
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3238<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3239
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3240<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3241<pre>
Bill Wendlingb3aa4712011-07-26 10:41:15 +0000[diff] [blame]3242 br i1 &lt;cond&gt;, label &lt;iftrue&gt;, label &lt;iffalse&gt;
3243 br label &lt;dest&gt; <i>; Unconditional branch</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3244</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3245
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3246<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3247<p>The '<tt>br</tt>' instruction is used to cause control flow to transfer to a
3248 different basic block in the current function. There are two forms of this
3249 instruction, corresponding to a conditional branch and an unconditional
3250 branch.</p>
3251
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3252<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3253<p>The conditional branch form of the '<tt>br</tt>' instruction takes a single
3254 '<tt>i1</tt>' value and two '<tt>label</tt>' values. The unconditional form
3255 of the '<tt>br</tt>' instruction takes a single '<tt>label</tt>' value as a
3256 target.</p>
3257
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3258<h5>Semantics:</h5>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3259<p>Upon execution of a conditional '<tt>br</tt>' instruction, the '<tt>i1</tt>'
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3260 argument is evaluated. If the value is <tt>true</tt>, control flows to the
3261 '<tt>iftrue</tt>' <tt>label</tt> argument. If "cond" is <tt>false</tt>,
3262 control flows to the '<tt>iffalse</tt>' <tt>label</tt> argument.</p>
3263
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3264<h5>Example:</h5>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]3265<pre>
3266Test:
3267 %cond = <a href="#i_icmp">icmp</a> eq i32 %a, %b
3268 br i1 %cond, label %IfEqual, label %IfUnequal
3269IfEqual:
3270 <a href="#i_ret">ret</a> i32 1
3271IfUnequal:
3272 <a href="#i_ret">ret</a> i32 0
3273</pre>
3274
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3275</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3276
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3277<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3278<h4>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3279 <a name="i_switch">'<tt>switch</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3280</h4>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3281
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3282<div>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3283
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3284<h5>Syntax:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3285<pre>
3286 switch &lt;intty&gt; &lt;value&gt;, label &lt;defaultdest&gt; [ &lt;intty&gt; &lt;val&gt;, label &lt;dest&gt; ... ]
3287</pre>
3288
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3289<h5>Overview:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3290<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]3291 several different places. It is a generalization of the '<tt>br</tt>'
3292 instruction, allowing a branch to occur to one of many possible
3293 destinations.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3294
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3295<h5>Arguments:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3296<p>The '<tt>switch</tt>' instruction uses three parameters: an integer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3297 comparison value '<tt>value</tt>', a default '<tt>label</tt>' destination,
3298 and an array of pairs of comparison value constants and '<tt>label</tt>'s.
3299 The table is not allowed to contain duplicate constant entries.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3300
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3301<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3302<p>The <tt>switch</tt> instruction specifies a table of values and
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3303 destinations. When the '<tt>switch</tt>' instruction is executed, this table
3304 is searched for the given value. If the value is found, control flow is
Benjamin Kramer8040cd32009-10-12 14:46:08 +0000[diff] [blame]3305 transferred to the corresponding destination; otherwise, control flow is
3306 transferred to the default destination.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3307
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3308<h5>Implementation:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3309<p>Depending on properties of the target machine and the particular
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3310 <tt>switch</tt> instruction, this instruction may be code generated in
3311 different ways. For example, it could be generated as a series of chained
3312 conditional branches or with a lookup table.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3313
3314<h5>Example:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3315<pre>
3316 <i>; Emulate a conditional br instruction</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3317 %Val = <a href="#i_zext">zext</a> i1 %value to i32
Dan Gohman2a08c532009-01-04 23:44:43 +0000[diff] [blame]3318 switch i32 %Val, label %truedest [ i32 0, label %falsedest ]
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3319
3320 <i>; Emulate an unconditional br instruction</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3321 switch i32 0, label %dest [ ]
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3322
3323 <i>; Implement a jump table:</i>
Dan Gohman2a08c532009-01-04 23:44:43 +0000[diff] [blame]3324 switch i32 %val, label %otherwise [ i32 0, label %onzero
3325 i32 1, label %onone
3326 i32 2, label %ontwo ]
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3327</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3328
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3329</div>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3330
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]3331
3332<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3333<h4>
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]3334 <a name="i_indirectbr">'<tt>indirectbr</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3335</h4>
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]3336
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3337<div>
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]3338
3339<h5>Syntax:</h5>
3340<pre>
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]3341 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]3342</pre>
3343
3344<h5>Overview:</h5>
3345
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]3346<p>The '<tt>indirectbr</tt>' instruction implements an indirect branch to a label
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]3347 within the current function, whose address is specified by
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]3348 "<tt>address</tt>". Address must be derived from a <a
3349 href="#blockaddress">blockaddress</a> constant.</p>
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]3350
3351<h5>Arguments:</h5>
3352
3353<p>The '<tt>address</tt>' argument is the address of the label to jump to. The
3354 rest of the arguments indicate the full set of possible destinations that the
3355 address may point to. Blocks are allowed to occur multiple times in the
3356 destination list, though this isn't particularly useful.</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3357
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]3358<p>This destination list is required so that dataflow analysis has an accurate
3359 understanding of the CFG.</p>
3360
3361<h5>Semantics:</h5>
3362
3363<p>Control transfers to the block specified in the address argument. All
3364 possible destination blocks must be listed in the label list, otherwise this
3365 instruction has undefined behavior. This implies that jumps to labels
3366 defined in other functions have undefined behavior as well.</p>
3367
3368<h5>Implementation:</h5>
3369
3370<p>This is typically implemented with a jump through a register.</p>
3371
3372<h5>Example:</h5>
3373<pre>
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]3374 indirectbr i8* %Addr, [ label %bb1, label %bb2, label %bb3 ]
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]3375</pre>
3376
3377</div>
3378
3379
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3380<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3381<h4>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3382 <a name="i_invoke">'<tt>invoke</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3383</h4>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3384
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3385<div>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3386
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3387<h5>Syntax:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3388<pre>
Devang Patel307e8ab2008-10-07 17:48:33 +0000[diff] [blame]3389 &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]3390 to label &lt;normal label&gt; unwind label &lt;exception label&gt;
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3391</pre>
3392
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]3393<h5>Overview:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3394<p>The '<tt>invoke</tt>' instruction causes control to transfer to a specified
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3395 function, with the possibility of control flow transfer to either the
3396 '<tt>normal</tt>' label or the '<tt>exception</tt>' label. If the callee
3397 function returns with the "<tt><a href="#i_ret">ret</a></tt>" instruction,
3398 control flow will return to the "normal" label. If the callee (or any
3399 indirect callees) returns with the "<a href="#i_unwind"><tt>unwind</tt></a>"
3400 instruction, control is interrupted and continued at the dynamically nearest
3401 "exception" label.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3402
Bill Wendlingf78faf82011-08-02 21:52:38 +0000[diff] [blame]3403<p>The '<tt>exception</tt>' label is a
3404 <i><a href="ExceptionHandling.html#overview">landing pad</a></i> for the
3405 exception. As such, '<tt>exception</tt>' label is required to have the
3406 "<a href="#i_landingpad"><tt>landingpad</tt></a>" instruction, which contains
3407 the information about about the behavior of the program after unwinding
3408 happens, as its first non-PHI instruction. The restrictions on the
3409 "<tt>landingpad</tt>" instruction's tightly couples it to the
3410 "<tt>invoke</tt>" instruction, so that the important information contained
3411 within the "<tt>landingpad</tt>" instruction can't be lost through normal
3412 code motion.</p>
3413
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3414<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3415<p>This instruction requires several arguments:</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3416
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3417<ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3418 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
3419 convention</a> the call should use. If none is specified, the call
3420 defaults to using C calling conventions.</li>
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]3421
3422 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3423 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
3424 '<tt>inreg</tt>' attributes are valid here.</li>
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]3425
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3426 <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]3427 function value being invoked. In most cases, this is a direct function
3428 invocation, but indirect <tt>invoke</tt>s are just as possible, branching
3429 off an arbitrary pointer to function value.</li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3430
3431 <li>'<tt>function ptr val</tt>': An LLVM value containing a pointer to a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3432 function to be invoked. </li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3433
3434 <li>'<tt>function args</tt>': argument list whose types match the function
Chris Lattner0724fbd2010-03-02 06:36:51 +0000[diff] [blame]3435 signature argument types and parameter attributes. All arguments must be
3436 of <a href="#t_firstclass">first class</a> type. If the function
3437 signature indicates the function accepts a variable number of arguments,
3438 the extra arguments can be specified.</li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3439
3440 <li>'<tt>normal label</tt>': the label reached when the called function
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3441 executes a '<tt><a href="#i_ret">ret</a></tt>' instruction. </li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3442
3443 <li>'<tt>exception label</tt>': the label reached when a callee returns with
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3444 the <a href="#i_unwind"><tt>unwind</tt></a> instruction. </li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3445
Devang Patel307e8ab2008-10-07 17:48:33 +0000[diff] [blame]3446 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3447 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
3448 '<tt>readnone</tt>' attributes are valid here.</li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3449</ol>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3450
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3451<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3452<p>This instruction is designed to operate as a standard
3453 '<tt><a href="#i_call">call</a></tt>' instruction in most regards. The
3454 primary difference is that it establishes an association with a label, which
3455 is used by the runtime library to unwind the stack.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3456
3457<p>This instruction is used in languages with destructors to ensure that proper
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3458 cleanup is performed in the case of either a <tt>longjmp</tt> or a thrown
3459 exception. Additionally, this is important for implementation of
3460 '<tt>catch</tt>' clauses in high-level languages that support them.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3461
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3462<p>For the purposes of the SSA form, the definition of the value returned by the
3463 '<tt>invoke</tt>' instruction is deemed to occur on the edge from the current
3464 block to the "normal" label. If the callee unwinds then no return value is
3465 available.</p>
Dan Gohmanf96a4992009-05-22 21:47:08 +0000[diff] [blame]3466
Chris Lattnerdf7a6802010-01-15 18:08:37 +0000[diff] [blame]3467<p>Note that the code generator does not yet completely support unwind, and
3468that the invoke/unwind semantics are likely to change in future versions.</p>
3469
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3470<h5>Example:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3471<pre>
Nick Lewyckyd703f652008-03-16 07:18:12 +0000[diff] [blame]3472 %retval = invoke i32 @Test(i32 15) to label %Continue
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]3473 unwind label %TestCleanup <i>; {i32}:retval set</i>
Nick Lewyckyd703f652008-03-16 07:18:12 +0000[diff] [blame]3474 %retval = invoke <a href="#callingconv">coldcc</a> i32 %Testfnptr(i32 15) to label %Continue
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]3475 unwind label %TestCleanup <i>; {i32}:retval set</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3476</pre>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3477
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3478</div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3479
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]3480<!-- _______________________________________________________________________ -->
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3481
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3482<h4>
3483 <a name="i_unwind">'<tt>unwind</tt>' Instruction</a>
3484</h4>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3485
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3486<div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3487
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]3488<h5>Syntax:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3489<pre>
3490 unwind
3491</pre>
3492
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]3493<h5>Overview:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3494<p>The '<tt>unwind</tt>' instruction unwinds the stack, continuing control flow
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3495 at the first callee in the dynamic call stack which used
3496 an <a href="#i_invoke"><tt>invoke</tt></a> instruction to perform the call.
3497 This is primarily used to implement exception handling.</p>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3498
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]3499<h5>Semantics:</h5>
Chris Lattner72ed2002008-04-19 21:01:16 +0000[diff] [blame]3500<p>The '<tt>unwind</tt>' instruction causes execution of the current function to
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3501 immediately halt. The dynamic call stack is then searched for the
3502 first <a href="#i_invoke"><tt>invoke</tt></a> instruction on the call stack.
3503 Once found, execution continues at the "exceptional" destination block
3504 specified by the <tt>invoke</tt> instruction. If there is no <tt>invoke</tt>
3505 instruction in the dynamic call chain, undefined behavior results.</p>
3506
Chris Lattnerdf7a6802010-01-15 18:08:37 +0000[diff] [blame]3507<p>Note that the code generator does not yet completely support unwind, and
3508that the invoke/unwind semantics are likely to change in future versions.</p>
3509
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3510</div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3511
Bill Wendlingdccc03b2011-07-31 06:30:59 +0000[diff] [blame]3512 <!-- _______________________________________________________________________ -->
3513
3514<h4>
3515 <a name="i_resume">'<tt>resume</tt>' Instruction</a>
3516</h4>
3517
3518<div>
3519
3520<h5>Syntax:</h5>
3521<pre>
3522 resume &lt;type&gt; &lt;value&gt;
3523</pre>
3524
3525<h5>Overview:</h5>
3526<p>The '<tt>resume</tt>' instruction is a terminator instruction that has no
3527 successors.</p>
3528
3529<h5>Arguments:</h5>
Bill Wendlingf78faf82011-08-02 21:52:38 +0000[diff] [blame]3530<p>The '<tt>resume</tt>' instruction requires one argument, which must have the
Bill Wendlinge4ad50b2011-08-03 18:37:32 +0000[diff] [blame]3531 same type as the result of any '<tt>landingpad</tt>' instruction in the same
3532 function.</p>
Bill Wendlingdccc03b2011-07-31 06:30:59 +0000[diff] [blame]3533
3534<h5>Semantics:</h5>
3535<p>The '<tt>resume</tt>' instruction resumes propagation of an existing
3536 (in-flight) exception whose unwinding was interrupted with
Bill Wendlingf78faf82011-08-02 21:52:38 +0000[diff] [blame]3537 a <a href="#i_landingpad"><tt>landingpad</tt></a> instruction.</p>
Bill Wendlingdccc03b2011-07-31 06:30:59 +0000[diff] [blame]3538
3539<h5>Example:</h5>
3540<pre>
Bill Wendlingf78faf82011-08-02 21:52:38 +0000[diff] [blame]3541 resume { i8*, i32 } %exn
Bill Wendlingdccc03b2011-07-31 06:30:59 +0000[diff] [blame]3542</pre>
3543
3544</div>
3545
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3546<!-- _______________________________________________________________________ -->
3547
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3548<h4>
3549 <a name="i_unreachable">'<tt>unreachable</tt>' Instruction</a>
3550</h4>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3551
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3552<div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3553
3554<h5>Syntax:</h5>
3555<pre>
3556 unreachable
3557</pre>
3558
3559<h5>Overview:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3560<p>The '<tt>unreachable</tt>' instruction has no defined semantics. This
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3561 instruction is used to inform the optimizer that a particular portion of the
3562 code is not reachable. This can be used to indicate that the code after a
3563 no-return function cannot be reached, and other facts.</p>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3564
3565<h5>Semantics:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3566<p>The '<tt>unreachable</tt>' instruction has no defined semantics.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3567
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3568</div>
3569
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3570</div>
3571
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3572<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3573<h3>
3574 <a name="binaryops">Binary Operations</a>
3575</h3>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3576
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3577<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3578
3579<p>Binary operators are used to do most of the computation in a program. They
3580 require two operands of the same type, execute an operation on them, and
3581 produce a single value. The operands might represent multiple data, as is
3582 the case with the <a href="#t_vector">vector</a> data type. The result value
3583 has the same type as its operands.</p>
3584
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3585<p>There are several different binary operators:</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3586
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3587<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3588<h4>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3589 <a name="i_add">'<tt>add</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3590</h4>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3591
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3592<div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3593
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3594<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3595<pre>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3596 &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]3597 &lt;result&gt; = add nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3598 &lt;result&gt; = add nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3599 &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]3600</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3601
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3602<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3603<p>The '<tt>add</tt>' instruction returns the sum of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3604
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3605<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3606<p>The two arguments to the '<tt>add</tt>' instruction must
3607 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3608 integer values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3609
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3610<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3611<p>The value produced is the integer sum of the two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3612
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3613<p>If the sum has unsigned overflow, the result returned is the mathematical
3614 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]3615
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3616<p>Because LLVM integers use a two's complement representation, this instruction
3617 is appropriate for both signed and unsigned integers.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3618
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]3619<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3620 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3621 <tt>nsw</tt> keywords are present, the result value of the <tt>add</tt>
Dan Gohmanbfb056d2011-12-06 03:18:47 +0000[diff] [blame]3622 is a <a href="#poisonvalues">poison value</a> if unsigned and/or signed overflow,
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]3623 respectively, occurs.</p>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3624
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3625<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3626<pre>
3627 &lt;result&gt; = add i32 4, %var <i>; yields {i32}:result = 4 + %var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3628</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3629
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3630</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3631
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3632<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3633<h4>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3634 <a name="i_fadd">'<tt>fadd</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3635</h4>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3636
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3637<div>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3638
3639<h5>Syntax:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3640<pre>
3641 &lt;result&gt; = fadd &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3642</pre>
3643
3644<h5>Overview:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3645<p>The '<tt>fadd</tt>' instruction returns the sum of its two operands.</p>
3646
3647<h5>Arguments:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3648<p>The two arguments to the '<tt>fadd</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3649 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3650 floating point values. Both arguments must have identical types.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3651
3652<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3653<p>The value produced is the floating point sum of the two operands.</p>
3654
3655<h5>Example:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3656<pre>
3657 &lt;result&gt; = fadd float 4.0, %var <i>; yields {float}:result = 4.0 + %var</i>
3658</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3659
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3660</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3661
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3662<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3663<h4>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3664 <a name="i_sub">'<tt>sub</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3665</h4>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3666
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3667<div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3668
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3669<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3670<pre>
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]3671 &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]3672 &lt;result&gt; = sub nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3673 &lt;result&gt; = sub nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3674 &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]3675</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3676
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3677<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3678<p>The '<tt>sub</tt>' instruction returns the difference of its two
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3679 operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3680
3681<p>Note that the '<tt>sub</tt>' instruction is used to represent the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3682 '<tt>neg</tt>' instruction present in most other intermediate
3683 representations.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3684
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3685<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3686<p>The two arguments to the '<tt>sub</tt>' instruction must
3687 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3688 integer values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3689
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3690<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3691<p>The value produced is the integer difference of the two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3692
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3693<p>If the difference has unsigned overflow, the result returned is the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3694 mathematical result modulo 2<sup>n</sup>, where n is the bit width of the
3695 result.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3696
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3697<p>Because LLVM integers use a two's complement representation, this instruction
3698 is appropriate for both signed and unsigned integers.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3699
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]3700<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3701 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3702 <tt>nsw</tt> keywords are present, the result value of the <tt>sub</tt>
Dan Gohmanbfb056d2011-12-06 03:18:47 +0000[diff] [blame]3703 is a <a href="#poisonvalues">poison value</a> if unsigned and/or signed overflow,
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]3704 respectively, occurs.</p>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3705
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3706<h5>Example:</h5>
Bill Wendlingaac388b2007-05-29 09:42:13 +0000[diff] [blame]3707<pre>
3708 &lt;result&gt; = sub i32 4, %var <i>; yields {i32}:result = 4 - %var</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3709 &lt;result&gt; = sub i32 0, %val <i>; yields {i32}:result = -%var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3710</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3711
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3712</div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3713
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3714<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3715<h4>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3716 <a name="i_fsub">'<tt>fsub</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3717</h4>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3718
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3719<div>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3720
3721<h5>Syntax:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3722<pre>
3723 &lt;result&gt; = fsub &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3724</pre>
3725
3726<h5>Overview:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3727<p>The '<tt>fsub</tt>' instruction returns the difference of its two
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3728 operands.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3729
3730<p>Note that the '<tt>fsub</tt>' instruction is used to represent the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3731 '<tt>fneg</tt>' instruction present in most other intermediate
3732 representations.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3733
3734<h5>Arguments:</h5>
Bill Wendlingd9fe2982009-07-20 02:32:41 +0000[diff] [blame]3735<p>The two arguments to the '<tt>fsub</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3736 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3737 floating point values. Both arguments must have identical types.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3738
3739<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3740<p>The value produced is the floating point difference of the two operands.</p>
3741
3742<h5>Example:</h5>
3743<pre>
3744 &lt;result&gt; = fsub float 4.0, %var <i>; yields {float}:result = 4.0 - %var</i>
3745 &lt;result&gt; = fsub float -0.0, %val <i>; yields {float}:result = -%var</i>
3746</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3747
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3748</div>
3749
3750<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3751<h4>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3752 <a name="i_mul">'<tt>mul</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3753</h4>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3754
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3755<div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3756
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3757<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3758<pre>
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]3759 &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]3760 &lt;result&gt; = mul nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3761 &lt;result&gt; = mul nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3762 &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]3763</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3764
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3765<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3766<p>The '<tt>mul</tt>' instruction returns the product of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3767
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3768<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3769<p>The two arguments to the '<tt>mul</tt>' instruction must
3770 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3771 integer values. Both arguments must have identical types.</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3772
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3773<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3774<p>The value produced is the integer product of the two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3775
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3776<p>If the result of the multiplication has unsigned overflow, the result
3777 returned is the mathematical result modulo 2<sup>n</sup>, where n is the bit
3778 width of the result.</p>
3779
3780<p>Because LLVM integers use a two's complement representation, and the result
3781 is the same width as the operands, this instruction returns the correct
3782 result for both signed and unsigned integers. If a full product
3783 (e.g. <tt>i32</tt>x<tt>i32</tt>-><tt>i64</tt>) is needed, the operands should
3784 be sign-extended or zero-extended as appropriate to the width of the full
3785 product.</p>
3786
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]3787<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3788 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3789 <tt>nsw</tt> keywords are present, the result value of the <tt>mul</tt>
Dan Gohmanbfb056d2011-12-06 03:18:47 +0000[diff] [blame]3790 is a <a href="#poisonvalues">poison value</a> if unsigned and/or signed overflow,
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]3791 respectively, occurs.</p>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3792
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3793<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3794<pre>
3795 &lt;result&gt; = mul i32 4, %var <i>; yields {i32}:result = 4 * %var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3796</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3797
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3798</div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3799
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3800<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3801<h4>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3802 <a name="i_fmul">'<tt>fmul</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3803</h4>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3804
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3805<div>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3806
3807<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3808<pre>
3809 &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]3810</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3811
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3812<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3813<p>The '<tt>fmul</tt>' instruction returns the product of its two operands.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3814
3815<h5>Arguments:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3816<p>The two arguments to the '<tt>fmul</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3817 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3818 floating point values. Both arguments must have identical types.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3819
3820<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3821<p>The value produced is the floating point product of the two operands.</p>
3822
3823<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3824<pre>
3825 &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]3826</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3827
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3828</div>
3829
3830<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3831<h4>
3832 <a name="i_udiv">'<tt>udiv</tt>' Instruction</a>
3833</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3834
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3835<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3836
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3837<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3838<pre>
Chris Lattner35bda892011-02-06 21:44:57 +0000[diff] [blame]3839 &lt;result&gt; = udiv &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3840 &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]3841</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3842
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3843<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3844<p>The '<tt>udiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3845
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3846<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3847<p>The two arguments to the '<tt>udiv</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3848 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3849 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3850
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3851<h5>Semantics:</h5>
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3852<p>The value produced is the unsigned integer quotient of the two operands.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3853
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3854<p>Note that unsigned integer division and signed integer division are distinct
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3855 operations; for signed integer division, use '<tt>sdiv</tt>'.</p>
3856
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3857<p>Division by zero leads to undefined behavior.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3858
Chris Lattner35bda892011-02-06 21:44:57 +0000[diff] [blame]3859<p>If the <tt>exact</tt> keyword is present, the result value of the
Dan Gohmanbfb056d2011-12-06 03:18:47 +0000[diff] [blame]3860 <tt>udiv</tt> is a <a href="#poisonvalues">poison value</a> if %op1 is not a
Chris Lattner35bda892011-02-06 21:44:57 +0000[diff] [blame]3861 multiple of %op2 (as such, "((a udiv exact b) mul b) == a").</p>
3862
3863
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3864<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3865<pre>
3866 &lt;result&gt; = udiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3867</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3868
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3869</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3870
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3871<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3872<h4>
3873 <a name="i_sdiv">'<tt>sdiv</tt>' Instruction</a>
3874</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3875
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3876<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3877
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3878<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3879<pre>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3880 &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]3881 &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]3882</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3883
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3884<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3885<p>The '<tt>sdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3886
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3887<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3888<p>The two arguments to the '<tt>sdiv</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3889 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3890 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3891
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3892<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3893<p>The value produced is the signed integer quotient of the two operands rounded
3894 towards zero.</p>
3895
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3896<p>Note that signed integer division and unsigned integer division are distinct
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3897 operations; for unsigned integer division, use '<tt>udiv</tt>'.</p>
3898
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3899<p>Division by zero leads to undefined behavior. Overflow also leads to
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3900 undefined behavior; this is a rare case, but can occur, for example, by doing
3901 a 32-bit division of -2147483648 by -1.</p>
3902
Dan Gohman9c5beed2009-07-22 00:04:19 +0000[diff] [blame]3903<p>If the <tt>exact</tt> keyword is present, the result value of the
Dan Gohmanbfb056d2011-12-06 03:18:47 +0000[diff] [blame]3904 <tt>sdiv</tt> is a <a href="#poisonvalues">poison value</a> if the result would
Dan Gohman38da9272010-07-11 00:08:34 +0000[diff] [blame]3905 be rounded.</p>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3906
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3907<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3908<pre>
3909 &lt;result&gt; = sdiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3910</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3911
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3912</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3913
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3914<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3915<h4>
3916 <a name="i_fdiv">'<tt>fdiv</tt>' Instruction</a>
3917</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3918
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3919<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3920
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3921<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3922<pre>
Gabor Greiffb224a22008-08-07 21:46:00 +0000[diff] [blame]3923 &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]3924</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3925
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3926<h5>Overview:</h5>
3927<p>The '<tt>fdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3928
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3929<h5>Arguments:</h5>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]3930<p>The two arguments to the '<tt>fdiv</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3931 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3932 floating point values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3933
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3934<h5>Semantics:</h5>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3935<p>The value produced is the floating point quotient of the two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3936
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3937<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3938<pre>
3939 &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]3940</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3941
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3942</div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3943
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3944<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3945<h4>
3946 <a name="i_urem">'<tt>urem</tt>' Instruction</a>
3947</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3948
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3949<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3950
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3951<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3952<pre>
3953 &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]3954</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3955
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3956<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3957<p>The '<tt>urem</tt>' instruction returns the remainder from the unsigned
3958 division of its two arguments.</p>
3959
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3960<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3961<p>The two arguments to the '<tt>urem</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3962 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3963 values. Both arguments must have identical types.</p>
3964
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3965<h5>Semantics:</h5>
3966<p>This instruction returns the unsigned integer <i>remainder</i> of a division.
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3967 This instruction always performs an unsigned division to get the
3968 remainder.</p>
3969
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3970<p>Note that unsigned integer remainder and signed integer remainder are
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3971 distinct operations; for signed integer remainder, use '<tt>srem</tt>'.</p>
3972
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3973<p>Taking the remainder of a division by zero leads to undefined behavior.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3974
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3975<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3976<pre>
3977 &lt;result&gt; = urem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3978</pre>
3979
3980</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3981
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3982<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3983<h4>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3984 <a name="i_srem">'<tt>srem</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3985</h4>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3986
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3987<div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3988
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3989<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3990<pre>
Gabor Greiffb224a22008-08-07 21:46:00 +0000[diff] [blame]3991 &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]3992</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3993
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3994<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3995<p>The '<tt>srem</tt>' instruction returns the remainder from the signed
3996 division of its two operands. This instruction can also take
3997 <a href="#t_vector">vector</a> versions of the values in which case the
3998 elements must be integers.</p>
Chris Lattnerc7d3ab32008-01-04 04:33:49 +0000[diff] [blame]3999
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4000<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4001<p>The two arguments to the '<tt>srem</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4002 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
4003 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4004
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4005<h5>Semantics:</h5>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]4006<p>This instruction returns the <i>remainder</i> of a division (where the result
Duncan Sandsdea3a5e2011-03-07 09:12:24 +0000[diff] [blame]4007 is either zero or has the same sign as the dividend, <tt>op1</tt>), not the
4008 <i>modulo</i> operator (where the result is either zero or has the same sign
4009 as the divisor, <tt>op2</tt>) of a value.
4010 For more information about the difference,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4011 see <a href="http://mathforum.org/dr.math/problems/anne.4.28.99.html">The
4012 Math Forum</a>. For a table of how this is implemented in various languages,
4013 please see <a href="http://en.wikipedia.org/wiki/Modulo_operation">
4014 Wikipedia: modulo operation</a>.</p>
4015
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]4016<p>Note that signed integer remainder and unsigned integer remainder are
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4017 distinct operations; for unsigned integer remainder, use '<tt>urem</tt>'.</p>
4018
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]4019<p>Taking the remainder of a division by zero leads to undefined behavior.
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4020 Overflow also leads to undefined behavior; this is a rare case, but can
4021 occur, for example, by taking the remainder of a 32-bit division of
4022 -2147483648 by -1. (The remainder doesn't actually overflow, but this rule
4023 lets srem be implemented using instructions that return both the result of
4024 the division and the remainder.)</p>
4025
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4026<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4027<pre>
4028 &lt;result&gt; = srem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]4029</pre>
4030
4031</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4032
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]4033<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4034<h4>
4035 <a name="i_frem">'<tt>frem</tt>' Instruction</a>
4036</h4>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4037
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4038<div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4039
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]4040<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4041<pre>
4042 &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]4043</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4044
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]4045<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4046<p>The '<tt>frem</tt>' instruction returns the remainder from the division of
4047 its two operands.</p>
4048
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]4049<h5>Arguments:</h5>
4050<p>The two arguments to the '<tt>frem</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4051 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
4052 floating point values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4053
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]4054<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4055<p>This instruction returns the <i>remainder</i> of a division. The remainder
4056 has the same sign as the dividend.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4057
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]4058<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4059<pre>
4060 &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]4061</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4062
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4063</div>
Robert Bocchino7b81c752006-02-17 21:18:08 +0000[diff] [blame]4064
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4065</div>
4066
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]4067<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4068<h3>
4069 <a name="bitwiseops">Bitwise Binary Operations</a>
4070</h3>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4071
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4072<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4073
4074<p>Bitwise binary operators are used to do various forms of bit-twiddling in a
4075 program. They are generally very efficient instructions and can commonly be
4076 strength reduced from other instructions. They require two operands of the
4077 same type, execute an operation on them, and produce a single value. The
4078 resulting value is the same type as its operands.</p>
4079
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4080<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4081<h4>
4082 <a name="i_shl">'<tt>shl</tt>' Instruction</a>
4083</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4084
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4085<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4086
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4087<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4088<pre>
Chris Lattnerf067d582011-02-07 16:40:21 +0000[diff] [blame]4089 &lt;result&gt; = shl &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
4090 &lt;result&gt; = shl nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
4091 &lt;result&gt; = shl nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
4092 &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]4093</pre>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]4094
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4095<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4096<p>The '<tt>shl</tt>' instruction returns the first operand shifted to the left
4097 a specified number of bits.</p>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]4098
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4099<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4100<p>Both arguments to the '<tt>shl</tt>' instruction must be the
4101 same <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
4102 integer type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4103
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4104<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4105<p>The value produced is <tt>op1</tt> * 2<sup><tt>op2</tt></sup> mod
4106 2<sup>n</sup>, where <tt>n</tt> is the width of the result. If <tt>op2</tt>
4107 is (statically or dynamically) negative or equal to or larger than the number
4108 of bits in <tt>op1</tt>, the result is undefined. If the arguments are
4109 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
4110 shift amount in <tt>op2</tt>.</p>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]4111
Chris Lattnerf067d582011-02-07 16:40:21 +0000[diff] [blame]4112<p>If the <tt>nuw</tt> keyword is present, then the shift produces a
Dan Gohmanbfb056d2011-12-06 03:18:47 +0000[diff] [blame]4113 <a href="#poisonvalues">poison value</a> if it shifts out any non-zero bits. If
Chris Lattner66298c12011-02-09 16:44:44 +0000[diff] [blame]4114 the <tt>nsw</tt> keyword is present, then the shift produces a
Dan Gohmanbfb056d2011-12-06 03:18:47 +0000[diff] [blame]4115 <a href="#poisonvalues">poison value</a> if it shifts out any bits that disagree
Chris Lattnerf067d582011-02-07 16:40:21 +0000[diff] [blame]4116 with the resultant sign bit. As such, NUW/NSW have the same semantics as
4117 they would if the shift were expressed as a mul instruction with the same
4118 nsw/nuw bits in (mul %op1, (shl 1, %op2)).</p>
4119
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4120<h5>Example:</h5>
4121<pre>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4122 &lt;result&gt; = shl i32 4, %var <i>; yields {i32}: 4 &lt;&lt; %var</i>
4123 &lt;result&gt; = shl i32 4, 2 <i>; yields {i32}: 16</i>
4124 &lt;result&gt; = shl i32 1, 10 <i>; yields {i32}: 1024</i>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]4125 &lt;result&gt; = shl i32 1, 32 <i>; undefined</i>
Mon P Wange9f10152008-12-09 05:46:39 +0000[diff] [blame]4126 &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]4127</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4128
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4129</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4130
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4131<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4132<h4>
4133 <a name="i_lshr">'<tt>lshr</tt>' Instruction</a>
4134</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4135
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4136<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4137
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4138<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4139<pre>
Chris Lattnerf067d582011-02-07 16:40:21 +0000[diff] [blame]4140 &lt;result&gt; = lshr &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
4141 &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]4142</pre>
4143
4144<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4145<p>The '<tt>lshr</tt>' instruction (logical shift right) returns the first
4146 operand shifted to the right a specified number of bits with zero fill.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4147
4148<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4149<p>Both arguments to the '<tt>lshr</tt>' instruction must be the same
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4150 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
4151 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4152
4153<h5>Semantics:</h5>
4154<p>This instruction always performs a logical shift right operation. The most
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4155 significant bits of the result will be filled with zero bits after the shift.
4156 If <tt>op2</tt> is (statically or dynamically) equal to or larger than the
4157 number of bits in <tt>op1</tt>, the result is undefined. If the arguments are
4158 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
4159 shift amount in <tt>op2</tt>.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4160
Chris Lattnerf067d582011-02-07 16:40:21 +0000[diff] [blame]4161<p>If the <tt>exact</tt> keyword is present, the result value of the
Dan Gohmanbfb056d2011-12-06 03:18:47 +0000[diff] [blame]4162 <tt>lshr</tt> is a <a href="#poisonvalues">poison value</a> if any of the bits
Chris Lattnerf067d582011-02-07 16:40:21 +0000[diff] [blame]4163 shifted out are non-zero.</p>
4164
4165
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4166<h5>Example:</h5>
4167<pre>
4168 &lt;result&gt; = lshr i32 4, 1 <i>; yields {i32}:result = 2</i>
4169 &lt;result&gt; = lshr i32 4, 2 <i>; yields {i32}:result = 1</i>
4170 &lt;result&gt; = lshr i8 4, 3 <i>; yields {i8}:result = 0</i>
4171 &lt;result&gt; = lshr i8 -2, 1 <i>; yields {i8}:result = 0x7FFFFFFF </i>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]4172 &lt;result&gt; = lshr i32 1, 32 <i>; undefined</i>
Mon P Wange9f10152008-12-09 05:46:39 +0000[diff] [blame]4173 &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]4174</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4175
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4176</div>
4177
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]4178<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4179<h4>
4180 <a name="i_ashr">'<tt>ashr</tt>' Instruction</a>
4181</h4>
4182
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4183<div>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4184
4185<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4186<pre>
Chris Lattnerf067d582011-02-07 16:40:21 +0000[diff] [blame]4187 &lt;result&gt; = ashr &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
4188 &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]4189</pre>
4190
4191<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4192<p>The '<tt>ashr</tt>' instruction (arithmetic shift right) returns the first
4193 operand shifted to the right a specified number of bits with sign
4194 extension.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4195
4196<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4197<p>Both arguments to the '<tt>ashr</tt>' instruction must be the same
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4198 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
4199 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4200
4201<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4202<p>This instruction always performs an arithmetic shift right operation, The
4203 most significant bits of the result will be filled with the sign bit
4204 of <tt>op1</tt>. If <tt>op2</tt> is (statically or dynamically) equal to or
4205 larger than the number of bits in <tt>op1</tt>, the result is undefined. If
4206 the arguments are vectors, each vector element of <tt>op1</tt> is shifted by
4207 the corresponding shift amount in <tt>op2</tt>.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4208
Chris Lattnerf067d582011-02-07 16:40:21 +0000[diff] [blame]4209<p>If the <tt>exact</tt> keyword is present, the result value of the
Dan Gohmanbfb056d2011-12-06 03:18:47 +0000[diff] [blame]4210 <tt>ashr</tt> is a <a href="#poisonvalues">poison value</a> if any of the bits
Chris Lattnerf067d582011-02-07 16:40:21 +0000[diff] [blame]4211 shifted out are non-zero.</p>
4212
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4213<h5>Example:</h5>
4214<pre>
4215 &lt;result&gt; = ashr i32 4, 1 <i>; yields {i32}:result = 2</i>
4216 &lt;result&gt; = ashr i32 4, 2 <i>; yields {i32}:result = 1</i>
4217 &lt;result&gt; = ashr i8 4, 3 <i>; yields {i8}:result = 0</i>
4218 &lt;result&gt; = ashr i8 -2, 1 <i>; yields {i8}:result = -1</i>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]4219 &lt;result&gt; = ashr i32 1, 32 <i>; undefined</i>
Mon P Wange9f10152008-12-09 05:46:39 +0000[diff] [blame]4220 &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]4221</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4222
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4223</div>
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_and">'<tt>and</tt>' Instruction</a>
4228</h4>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4229
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4230<div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4231
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4232<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4233<pre>
Gabor Greiffb224a22008-08-07 21:46:00 +0000[diff] [blame]4234 &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]4235</pre>
Chris Lattner5568e942008-05-20 20:48:21 +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>and</tt>' instruction returns the bitwise logical and of its two
4239 operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4240
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4241<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4242<p>The two arguments to the '<tt>and</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4243 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
4244 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4245
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4246<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4247<p>The truth table used for the '<tt>and</tt>' instruction is:</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4248
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4249<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4250 <tbody>
4251 <tr>
4252 <td>In0</td>
4253 <td>In1</td>
4254 <td>Out</td>
4255 </tr>
4256 <tr>
4257 <td>0</td>
4258 <td>0</td>
4259 <td>0</td>
4260 </tr>
4261 <tr>
4262 <td>0</td>
4263 <td>1</td>
4264 <td>0</td>
4265 </tr>
4266 <tr>
4267 <td>1</td>
4268 <td>0</td>
4269 <td>0</td>
4270 </tr>
4271 <tr>
4272 <td>1</td>
4273 <td>1</td>
4274 <td>1</td>
4275 </tr>
4276 </tbody>
4277</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4278
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4279<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4280<pre>
4281 &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]4282 &lt;result&gt; = and i32 15, 40 <i>; yields {i32}:result = 8</i>
4283 &lt;result&gt; = and i32 4, 8 <i>; yields {i32}:result = 0</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4284</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4285</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4286<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4287<h4>
4288 <a name="i_or">'<tt>or</tt>' Instruction</a>
4289</h4>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4290
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4291<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4292
4293<h5>Syntax:</h5>
4294<pre>
4295 &lt;result&gt; = or &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
4296</pre>
4297
4298<h5>Overview:</h5>
4299<p>The '<tt>or</tt>' instruction returns the bitwise logical inclusive or of its
4300 two operands.</p>
4301
4302<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4303<p>The two arguments to the '<tt>or</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4304 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
4305 values. Both arguments must have identical types.</p>
4306
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4307<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4308<p>The truth table used for the '<tt>or</tt>' instruction is:</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4309
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4310<table border="1" cellspacing="0" cellpadding="4">
4311 <tbody>
4312 <tr>
4313 <td>In0</td>
4314 <td>In1</td>
4315 <td>Out</td>
4316 </tr>
4317 <tr>
4318 <td>0</td>
4319 <td>0</td>
4320 <td>0</td>
4321 </tr>
4322 <tr>
4323 <td>0</td>
4324 <td>1</td>
4325 <td>1</td>
4326 </tr>
4327 <tr>
4328 <td>1</td>
4329 <td>0</td>
4330 <td>1</td>
4331 </tr>
4332 <tr>
4333 <td>1</td>
4334 <td>1</td>
4335 <td>1</td>
4336 </tr>
4337 </tbody>
4338</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4339
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4340<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4341<pre>
4342 &lt;result&gt; = or i32 4, %var <i>; yields {i32}:result = 4 | %var</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4343 &lt;result&gt; = or i32 15, 40 <i>; yields {i32}:result = 47</i>
4344 &lt;result&gt; = or i32 4, 8 <i>; yields {i32}:result = 12</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4345</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4346
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4347</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4348
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4349<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4350<h4>
4351 <a name="i_xor">'<tt>xor</tt>' Instruction</a>
4352</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4353
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4354<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4355
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4356<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4357<pre>
4358 &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]4359</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4360
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4361<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4362<p>The '<tt>xor</tt>' instruction returns the bitwise logical exclusive or of
4363 its two operands. The <tt>xor</tt> is used to implement the "one's
4364 complement" operation, which is the "~" operator in C.</p>
4365
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4366<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4367<p>The two arguments to the '<tt>xor</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4368 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
4369 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4370
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4371<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4372<p>The truth table used for the '<tt>xor</tt>' instruction is:</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4373
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4374<table border="1" cellspacing="0" cellpadding="4">
4375 <tbody>
4376 <tr>
4377 <td>In0</td>
4378 <td>In1</td>
4379 <td>Out</td>
4380 </tr>
4381 <tr>
4382 <td>0</td>
4383 <td>0</td>
4384 <td>0</td>
4385 </tr>
4386 <tr>
4387 <td>0</td>
4388 <td>1</td>
4389 <td>1</td>
4390 </tr>
4391 <tr>
4392 <td>1</td>
4393 <td>0</td>
4394 <td>1</td>
4395 </tr>
4396 <tr>
4397 <td>1</td>
4398 <td>1</td>
4399 <td>0</td>
4400 </tr>
4401 </tbody>
4402</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4403
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4404<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4405<pre>
4406 &lt;result&gt; = xor i32 4, %var <i>; yields {i32}:result = 4 ^ %var</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4407 &lt;result&gt; = xor i32 15, 40 <i>; yields {i32}:result = 39</i>
4408 &lt;result&gt; = xor i32 4, 8 <i>; yields {i32}:result = 12</i>
4409 &lt;result&gt; = xor i32 %V, -1 <i>; yields {i32}:result = ~%V</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4410</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4411
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4412</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4413
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4414</div>
4415
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4416<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4417<h3>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4418 <a name="vectorops">Vector Operations</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4419</h3>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4420
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4421<div>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4422
4423<p>LLVM supports several instructions to represent vector operations in a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4424 target-independent manner. These instructions cover the element-access and
4425 vector-specific operations needed to process vectors effectively. While LLVM
4426 does directly support these vector operations, many sophisticated algorithms
4427 will want to use target-specific intrinsics to take full advantage of a
4428 specific target.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4429
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4430<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4431<h4>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4432 <a name="i_extractelement">'<tt>extractelement</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4433</h4>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4434
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4435<div>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4436
4437<h5>Syntax:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4438<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4439 &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]4440</pre>
4441
4442<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4443<p>The '<tt>extractelement</tt>' instruction extracts a single scalar element
4444 from a vector at a specified index.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4445
4446
4447<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4448<p>The first operand of an '<tt>extractelement</tt>' instruction is a value
4449 of <a href="#t_vector">vector</a> type. The second operand is an index
4450 indicating the position from which to extract the element. The index may be
4451 a variable.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4452
4453<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4454<p>The result is a scalar of the same type as the element type of
4455 <tt>val</tt>. Its value is the value at position <tt>idx</tt> of
4456 <tt>val</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
4457 results are undefined.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4458
4459<h5>Example:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4460<pre>
Gabor Greifa5b6f452009-10-28 13:14:50 +0000[diff] [blame]4461 &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]4462</pre>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4463
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4464</div>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4465
4466<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4467<h4>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4468 <a name="i_insertelement">'<tt>insertelement</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4469</h4>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4470
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4471<div>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4472
4473<h5>Syntax:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4474<pre>
Dan Gohmanf3480b92008-05-12 23:38:42 +0000[diff] [blame]4475 &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]4476</pre>
4477
4478<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4479<p>The '<tt>insertelement</tt>' instruction inserts a scalar element into a
4480 vector at a specified index.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4481
4482<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4483<p>The first operand of an '<tt>insertelement</tt>' instruction is a value
4484 of <a href="#t_vector">vector</a> type. The second operand is a scalar value
4485 whose type must equal the element type of the first operand. The third
4486 operand is an index indicating the position at which to insert the value.
4487 The index may be a variable.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4488
4489<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4490<p>The result is a vector of the same type as <tt>val</tt>. Its element values
4491 are those of <tt>val</tt> except at position <tt>idx</tt>, where it gets the
4492 value <tt>elt</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
4493 results are undefined.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4494
4495<h5>Example:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4496<pre>
Gabor Greifa5b6f452009-10-28 13:14:50 +0000[diff] [blame]4497 &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]4498</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4499
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4500</div>
4501
4502<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4503<h4>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4504 <a name="i_shufflevector">'<tt>shufflevector</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4505</h4>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4506
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4507<div>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4508
4509<h5>Syntax:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4510<pre>
Mon P Wangaeb06d22008-11-10 04:46:22 +0000[diff] [blame]4511 &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]4512</pre>
4513
4514<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4515<p>The '<tt>shufflevector</tt>' instruction constructs a permutation of elements
4516 from two input vectors, returning a vector with the same element type as the
4517 input and length that is the same as the shuffle mask.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4518
4519<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4520<p>The first two operands of a '<tt>shufflevector</tt>' instruction are vectors
4521 with types that match each other. The third argument is a shuffle mask whose
4522 element type is always 'i32'. The result of the instruction is a vector
4523 whose length is the same as the shuffle mask and whose element type is the
4524 same as the element type of the first two operands.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4525
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4526<p>The shuffle mask operand is required to be a constant vector with either
4527 constant integer or undef values.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4528
4529<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4530<p>The elements of the two input vectors are numbered from left to right across
4531 both of the vectors. The shuffle mask operand specifies, for each element of
4532 the result vector, which element of the two input vectors the result element
4533 gets. The element selector may be undef (meaning "don't care") and the
4534 second operand may be undef if performing a shuffle from only one vector.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4535
4536<h5>Example:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4537<pre>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4538 &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]4539 &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]4540 &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]4541 &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]4542 &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]4543 &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]4544 &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]4545 &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]4546</pre>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4547
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4548</div>
Tanya Lattner09474292006-04-14 19:24:33 +0000[diff] [blame]4549
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4550</div>
4551
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4552<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4553<h3>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4554 <a name="aggregateops">Aggregate Operations</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4555</h3>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4556
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4557<div>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4558
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4559<p>LLVM supports several instructions for working with
4560 <a href="#t_aggregate">aggregate</a> values.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4561
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4562<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4563<h4>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4564 <a name="i_extractvalue">'<tt>extractvalue</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4565</h4>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4566
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4567<div>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4568
4569<h5>Syntax:</h5>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4570<pre>
4571 &lt;result&gt; = extractvalue &lt;aggregate type&gt; &lt;val&gt;, &lt;idx&gt;{, &lt;idx&gt;}*
4572</pre>
4573
4574<h5>Overview:</h5>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4575<p>The '<tt>extractvalue</tt>' instruction extracts the value of a member field
4576 from an <a href="#t_aggregate">aggregate</a> value.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4577
4578<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4579<p>The first operand of an '<tt>extractvalue</tt>' instruction is a value
Chris Lattner61c70e92010-08-28 04:09:24 +0000[diff] [blame]4580 of <a href="#t_struct">struct</a> or
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4581 <a href="#t_array">array</a> type. The operands are constant indices to
4582 specify which value to extract in a similar manner as indices in a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4583 '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
Frits van Bommel13242892010-12-05 20:54:38 +0000[diff] [blame]4584 <p>The major differences to <tt>getelementptr</tt> indexing are:</p>
4585 <ul>
4586 <li>Since the value being indexed is not a pointer, the first index is
4587 omitted and assumed to be zero.</li>
4588 <li>At least one index must be specified.</li>
4589 <li>Not only struct indices but also array indices must be in
4590 bounds.</li>
4591 </ul>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4592
4593<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4594<p>The result is the value at the position in the aggregate specified by the
4595 index operands.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4596
4597<h5>Example:</h5>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4598<pre>
Gabor Greifa5b6f452009-10-28 13:14:50 +0000[diff] [blame]4599 &lt;result&gt; = extractvalue {i32, float} %agg, 0 <i>; yields i32</i>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4600</pre>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4601
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4602</div>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4603
4604<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4605<h4>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4606 <a name="i_insertvalue">'<tt>insertvalue</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4607</h4>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4608
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4609<div>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4610
4611<h5>Syntax:</h5>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4612<pre>
Bill Wendling194229e2011-07-26 20:42:28 +0000[diff] [blame]4613 &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]4614</pre>
4615
4616<h5>Overview:</h5>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4617<p>The '<tt>insertvalue</tt>' instruction inserts a value into a member field
4618 in an <a href="#t_aggregate">aggregate</a> value.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4619
4620<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4621<p>The first operand of an '<tt>insertvalue</tt>' instruction is a value
Chris Lattner61c70e92010-08-28 04:09:24 +0000[diff] [blame]4622 of <a href="#t_struct">struct</a> or
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4623 <a href="#t_array">array</a> type. The second operand is a first-class
4624 value to insert. The following operands are constant indices indicating
4625 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]4626 '<tt><a href="#i_extractvalue">extractvalue</a></tt>' instruction. The
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4627 value to insert must have the same type as the value identified by the
4628 indices.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4629
4630<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4631<p>The result is an aggregate of the same type as <tt>val</tt>. Its value is
4632 that of <tt>val</tt> except that the value at the position specified by the
4633 indices is that of <tt>elt</tt>.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4634
4635<h5>Example:</h5>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4636<pre>
Chris Lattner8645d1a2011-05-22 07:18:08 +0000[diff] [blame]4637 %agg1 = insertvalue {i32, float} undef, i32 1, 0 <i>; yields {i32 1, float undef}</i>
4638 %agg2 = insertvalue {i32, float} %agg1, float %val, 1 <i>; yields {i32 1, float %val}</i>
4639 %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]4640</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4641
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4642</div>
4643
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4644</div>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4645
4646<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4647<h3>
Chris Lattner884a9702006-08-15 00:45:58 +0000[diff] [blame]4648 <a name="memoryops">Memory Access and Addressing Operations</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4649</h3>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4650
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4651<div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4652
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4653<p>A key design point of an SSA-based representation is how it represents
4654 memory. In LLVM, no memory locations are in SSA form, which makes things
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]4655 very simple. This section describes how to read, write, and allocate
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4656 memory in LLVM.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4657
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4658<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4659<h4>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4660 <a name="i_alloca">'<tt>alloca</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4661</h4>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4662
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4663<div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4664
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4665<h5>Syntax:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4666<pre>
Dan Gohmanf75a7d32010-05-28 01:14:11 +0000[diff] [blame]4667 &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]4668</pre>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4669
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4670<h5>Overview:</h5>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]4671<p>The '<tt>alloca</tt>' instruction allocates memory on the stack frame of the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4672 currently executing function, to be automatically released when this function
4673 returns to its caller. The object is always allocated in the generic address
4674 space (address space zero).</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4675
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4676<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4677<p>The '<tt>alloca</tt>' instruction
4678 allocates <tt>sizeof(&lt;type&gt;)*NumElements</tt> bytes of memory on the
4679 runtime stack, returning a pointer of the appropriate type to the program.
4680 If "NumElements" is specified, it is the number of elements allocated,
4681 otherwise "NumElements" is defaulted to be one. If a constant alignment is
4682 specified, the value result of the allocation is guaranteed to be aligned to
4683 at least that boundary. If not specified, or if zero, the target can choose
4684 to align the allocation on any convenient boundary compatible with the
4685 type.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4686
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4687<p>'<tt>type</tt>' may be any sized type.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4688
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4689<h5>Semantics:</h5>
Bill Wendling871eb0a2009-05-08 20:49:29 +0000[diff] [blame]4690<p>Memory is allocated; a pointer is returned. The operation is undefined if
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4691 there is insufficient stack space for the allocation. '<tt>alloca</tt>'d
4692 memory is automatically released when the function returns. The
4693 '<tt>alloca</tt>' instruction is commonly used to represent automatic
4694 variables that must have an address available. When the function returns
4695 (either with the <tt><a href="#i_ret">ret</a></tt>
4696 or <tt><a href="#i_unwind">unwind</a></tt> instructions), the memory is
4697 reclaimed. Allocating zero bytes is legal, but the result is undefined.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4698
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4699<h5>Example:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4700<pre>
Dan Gohman81e21672009-01-04 23:49:44 +0000[diff] [blame]4701 %ptr = alloca i32 <i>; yields {i32*}:ptr</i>
4702 %ptr = alloca i32, i32 4 <i>; yields {i32*}:ptr</i>
4703 %ptr = alloca i32, i32 4, align 1024 <i>; yields {i32*}:ptr</i>
4704 %ptr = alloca i32, align 1024 <i>; yields {i32*}:ptr</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4705</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4706
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4707</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4708
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4709<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4710<h4>
4711 <a name="i_load">'<tt>load</tt>' Instruction</a>
4712</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4713
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4714<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4715
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4716<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4717<pre>
Eli Friedmanf03bb262011-08-12 22:50:01 +0000[diff] [blame]4718 &lt;result&gt; = load [volatile] &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;][, !nontemporal !&lt;index&gt;]
4719 &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]4720 !&lt;index&gt; = !{ i32 1 }
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4721</pre>
4722
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4723<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4724<p>The '<tt>load</tt>' instruction is used to read from memory.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4725
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4726<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4727<p>The argument to the '<tt>load</tt>' instruction specifies the memory address
4728 from which to load. The pointer must point to
4729 a <a href="#t_firstclass">first class</a> type. If the <tt>load</tt> is
4730 marked as <tt>volatile</tt>, then the optimizer is not allowed to modify the
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]4731 number or order of execution of this <tt>load</tt> with other <a
4732 href="#volatile">volatile operations</a>.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4733
Eli Friedman21006d42011-08-09 23:02:53 +0000[diff] [blame]4734<p>If the <code>load</code> is marked as <code>atomic</code>, it takes an extra
4735 <a href="#ordering">ordering</a> and optional <code>singlethread</code>
4736 argument. The <code>release</code> and <code>acq_rel</code> orderings are
4737 not valid on <code>load</code> instructions. Atomic loads produce <a
4738 href="#memorymodel">defined</a> results when they may see multiple atomic
4739 stores. The type of the pointee must be an integer type whose bit width
4740 is a power of two greater than or equal to eight and less than or equal
4741 to a target-specific size limit. <code>align</code> must be explicitly
4742 specified on atomic loads, and the load has undefined behavior if the
4743 alignment is not set to a value which is at least the size in bytes of
4744 the pointee. <code>!nontemporal</code> does not have any defined semantics
4745 for atomic loads.</p>
4746
Bill Wendling7c78dbb2010-02-25 21:23:24 +0000[diff] [blame]4747<p>The optional constant <tt>align</tt> argument specifies the alignment of the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4748 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]4749 omitted <tt>align</tt> argument means that the operation has the preferential
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4750 alignment for the target. It is the responsibility of the code emitter to
4751 ensure that the alignment information is correct. Overestimating the
Bill Wendling7c78dbb2010-02-25 21:23:24 +0000[diff] [blame]4752 alignment results in undefined behavior. Underestimating the alignment may
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4753 produce less efficient code. An alignment of 1 is always safe.</p>
4754
Bill Wendling7c78dbb2010-02-25 21:23:24 +0000[diff] [blame]4755<p>The optional <tt>!nontemporal</tt> metadata must reference a single
4756 metatadata name &lt;index&gt; corresponding to a metadata node with
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]4757 one <tt>i32</tt> entry of value 1. The existence of
Bill Wendling7c78dbb2010-02-25 21:23:24 +0000[diff] [blame]4758 the <tt>!nontemporal</tt> metatadata on the instruction tells the optimizer
4759 and code generator that this load is not expected to be reused in the cache.
4760 The code generator may select special instructions to save cache bandwidth,
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]4761 such as the <tt>MOVNT</tt> instruction on x86.</p>
David Greene8939b0d2010-02-16 20:50:18 +0000[diff] [blame]4762
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4763<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4764<p>The location of memory pointed to is loaded. If the value being loaded is of
4765 scalar type then the number of bytes read does not exceed the minimum number
4766 of bytes needed to hold all bits of the type. For example, loading an
4767 <tt>i24</tt> reads at most three bytes. When loading a value of a type like
4768 <tt>i20</tt> with a size that is not an integral number of bytes, the result
4769 is undefined if the value was not originally written using a store of the
4770 same type.</p>
4771
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4772<h5>Examples:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4773<pre>
4774 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
4775 <a href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4776 %val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4777</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4778
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4779</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4780
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4781<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4782<h4>
4783 <a name="i_store">'<tt>store</tt>' Instruction</a>
4784</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4785
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4786<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4787
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4788<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4789<pre>
Eli Friedmanf03bb262011-08-12 22:50:01 +0000[diff] [blame]4790 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>
4791 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]4792</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4793
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4794<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4795<p>The '<tt>store</tt>' instruction is used to write to memory.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4796
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4797<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4798<p>There are two arguments to the '<tt>store</tt>' instruction: a value to store
4799 and an address at which to store it. The type of the
4800 '<tt>&lt;pointer&gt;</tt>' operand must be a pointer to
4801 the <a href="#t_firstclass">first class</a> type of the
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]4802 '<tt>&lt;value&gt;</tt>' operand. If the <tt>store</tt> is marked as
4803 <tt>volatile</tt>, then the optimizer is not allowed to modify the number or
4804 order of execution of this <tt>store</tt> with other <a
4805 href="#volatile">volatile operations</a>.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4806
Eli Friedman21006d42011-08-09 23:02:53 +0000[diff] [blame]4807<p>If the <code>store</code> is marked as <code>atomic</code>, it takes an extra
4808 <a href="#ordering">ordering</a> and optional <code>singlethread</code>
4809 argument. The <code>acquire</code> and <code>acq_rel</code> orderings aren't
4810 valid on <code>store</code> instructions. Atomic loads produce <a
4811 href="#memorymodel">defined</a> results when they may see multiple atomic
4812 stores. The type of the pointee must be an integer type whose bit width
4813 is a power of two greater than or equal to eight and less than or equal
4814 to a target-specific size limit. <code>align</code> must be explicitly
4815 specified on atomic stores, and the store has undefined behavior if the
4816 alignment is not set to a value which is at least the size in bytes of
4817 the pointee. <code>!nontemporal</code> does not have any defined semantics
4818 for atomic stores.</p>
4819
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4820<p>The optional constant "align" argument specifies the alignment of the
4821 operation (that is, the alignment of the memory address). A value of 0 or an
4822 omitted "align" argument means that the operation has the preferential
4823 alignment for the target. It is the responsibility of the code emitter to
4824 ensure that the alignment information is correct. Overestimating the
4825 alignment results in an undefined behavior. Underestimating the alignment may
4826 produce less efficient code. An alignment of 1 is always safe.</p>
4827
David Greene8939b0d2010-02-16 20:50:18 +0000[diff] [blame]4828<p>The optional !nontemporal metadata must reference a single metatadata
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]4829 name &lt;index&gt; corresponding to a metadata node with one i32 entry of
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]4830 value 1. The existence of the !nontemporal metatadata on the
David Greene8939b0d2010-02-16 20:50:18 +0000[diff] [blame]4831 instruction tells the optimizer and code generator that this load is
4832 not expected to be reused in the cache. The code generator may
4833 select special instructions to save cache bandwidth, such as the
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]4834 MOVNT instruction on x86.</p>
David Greene8939b0d2010-02-16 20:50:18 +0000[diff] [blame]4835
4836
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4837<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4838<p>The contents of memory are updated to contain '<tt>&lt;value&gt;</tt>' at the
4839 location specified by the '<tt>&lt;pointer&gt;</tt>' operand. If
4840 '<tt>&lt;value&gt;</tt>' is of scalar type then the number of bytes written
4841 does not exceed the minimum number of bytes needed to hold all bits of the
4842 type. For example, storing an <tt>i24</tt> writes at most three bytes. When
4843 writing a value of a type like <tt>i20</tt> with a size that is not an
4844 integral number of bytes, it is unspecified what happens to the extra bits
4845 that do not belong to the type, but they will typically be overwritten.</p>
4846
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4847<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4848<pre>
4849 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Bill Wendling8c6c72d2007-10-22 05:10:05 +0000[diff] [blame]4850 store i32 3, i32* %ptr <i>; yields {void}</i>
4851 %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]4852</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4853
Reid Spencer47ce1792006-11-09 21:15:49 +0000[diff] [blame]4854</div>
4855
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4856<!-- _______________________________________________________________________ -->
NAKAMURA Takumib5bb29c2011-08-12 06:17:17 +0000[diff] [blame]4857<h4>
4858<a name="i_fence">'<tt>fence</tt>' Instruction</a>
4859</h4>
Eli Friedman47f35132011-07-25 23:16:38 +0000[diff] [blame]4860
NAKAMURA Takumib5bb29c2011-08-12 06:17:17 +0000[diff] [blame]4861<div>
Eli Friedman47f35132011-07-25 23:16:38 +0000[diff] [blame]4862
4863<h5>Syntax:</h5>
4864<pre>
4865 fence [singlethread] &lt;ordering&gt; <i>; yields {void}</i>
4866</pre>
4867
4868<h5>Overview:</h5>
4869<p>The '<tt>fence</tt>' instruction is used to introduce happens-before edges
4870between operations.</p>
4871
4872<h5>Arguments:</h5> <p>'<code>fence</code>' instructions take an <a
4873href="#ordering">ordering</a> argument which defines what
4874<i>synchronizes-with</i> edges they add. They can only be given
4875<code>acquire</code>, <code>release</code>, <code>acq_rel</code>, and
4876<code>seq_cst</code> orderings.</p>
4877
4878<h5>Semantics:</h5>
4879<p>A fence <var>A</var> which has (at least) <code>release</code> ordering
4880semantics <i>synchronizes with</i> a fence <var>B</var> with (at least)
4881<code>acquire</code> ordering semantics if and only if there exist atomic
4882operations <var>X</var> and <var>Y</var>, both operating on some atomic object
4883<var>M</var>, such that <var>A</var> is sequenced before <var>X</var>,
4884<var>X</var> modifies <var>M</var> (either directly or through some side effect
4885of a sequence headed by <var>X</var>), <var>Y</var> is sequenced before
4886<var>B</var>, and <var>Y</var> observes <var>M</var>. This provides a
4887<i>happens-before</i> dependency between <var>A</var> and <var>B</var>. Rather
4888than an explicit <code>fence</code>, one (but not both) of the atomic operations
4889<var>X</var> or <var>Y</var> might provide a <code>release</code> or
4890<code>acquire</code> (resp.) ordering constraint and still
4891<i>synchronize-with</i> the explicit <code>fence</code> and establish the
4892<i>happens-before</i> edge.</p>
4893
4894<p>A <code>fence</code> which has <code>seq_cst</code> ordering, in addition to
4895having both <code>acquire</code> and <code>release</code> semantics specified
4896above, participates in the global program order of other <code>seq_cst</code>
4897operations and/or fences.</p>
4898
4899<p>The optional "<a href="#singlethread"><code>singlethread</code></a>" argument
4900specifies that the fence only synchronizes with other fences in the same
4901thread. (This is useful for interacting with signal handlers.)</p>
4902
Eli Friedman47f35132011-07-25 23:16:38 +0000[diff] [blame]4903<h5>Example:</h5>
4904<pre>
4905 fence acquire <i>; yields {void}</i>
4906 fence singlethread seq_cst <i>; yields {void}</i>
4907</pre>
4908
4909</div>
4910
4911<!-- _______________________________________________________________________ -->
NAKAMURA Takumib5bb29c2011-08-12 06:17:17 +0000[diff] [blame]4912<h4>
4913<a name="i_cmpxchg">'<tt>cmpxchg</tt>' Instruction</a>
4914</h4>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]4915
NAKAMURA Takumib5bb29c2011-08-12 06:17:17 +0000[diff] [blame]4916<div>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]4917
4918<h5>Syntax:</h5>
4919<pre>
Eli Friedmanf03bb262011-08-12 22:50:01 +0000[diff] [blame]4920 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]4921</pre>
4922
4923<h5>Overview:</h5>
4924<p>The '<tt>cmpxchg</tt>' instruction is used to atomically modify memory.
4925It loads a value in memory and compares it to a given value. If they are
4926equal, it stores a new value into the memory.</p>
4927
4928<h5>Arguments:</h5>
4929<p>There are three arguments to the '<code>cmpxchg</code>' instruction: an
4930address to operate on, a value to compare to the value currently be at that
4931address, and a new value to place at that address if the compared values are
4932equal. The type of '<var>&lt;cmp&gt;</var>' must be an integer type whose
4933bit width is a power of two greater than or equal to eight and less than
4934or equal to a target-specific size limit. '<var>&lt;cmp&gt;</var>' and
4935'<var>&lt;new&gt;</var>' must have the same type, and the type of
4936'<var>&lt;pointer&gt;</var>' must be a pointer to that type. If the
4937<code>cmpxchg</code> is marked as <code>volatile</code>, then the
4938optimizer is not allowed to modify the number or order of execution
4939of this <code>cmpxchg</code> with other <a href="#volatile">volatile
4940operations</a>.</p>
4941
4942<!-- FIXME: Extend allowed types. -->
4943
4944<p>The <a href="#ordering"><var>ordering</var></a> argument specifies how this
4945<code>cmpxchg</code> synchronizes with other atomic operations.</p>
4946
4947<p>The optional "<code>singlethread</code>" argument declares that the
4948<code>cmpxchg</code> is only atomic with respect to code (usually signal
4949handlers) running in the same thread as the <code>cmpxchg</code>. Otherwise the
4950cmpxchg is atomic with respect to all other code in the system.</p>
4951
4952<p>The pointer passed into cmpxchg must have alignment greater than or equal to
4953the size in memory of the operand.
4954
4955<h5>Semantics:</h5>
4956<p>The contents of memory at the location specified by the
4957'<tt>&lt;pointer&gt;</tt>' operand is read and compared to
4958'<tt>&lt;cmp&gt;</tt>'; if the read value is the equal,
4959'<tt>&lt;new&gt;</tt>' is written. The original value at the location
4960is returned.
4961
4962<p>A successful <code>cmpxchg</code> is a read-modify-write instruction for the
4963purpose of identifying <a href="#release_sequence">release sequences</a>. A
4964failed <code>cmpxchg</code> is equivalent to an atomic load with an ordering
4965parameter determined by dropping any <code>release</code> part of the
4966<code>cmpxchg</code>'s ordering.</p>
4967
4968<!--
4969FIXME: Is compare_exchange_weak() necessary? (Consider after we've done
4970optimization work on ARM.)
4971
4972FIXME: Is a weaker ordering constraint on failure helpful in practice?
4973-->
4974
4975<h5>Example:</h5>
4976<pre>
4977entry:
4978 %orig = atomic <a href="#i_load">load</a> i32* %ptr unordered <i>; yields {i32}</i>
4979 <a href="#i_br">br</a> label %loop
4980
4981loop:
4982 %cmp = <a href="#i_phi">phi</a> i32 [ %orig, %entry ], [%old, %loop]
4983 %squared = <a href="#i_mul">mul</a> i32 %cmp, %cmp
4984 %old = cmpxchg i32* %ptr, i32 %cmp, i32 %squared <i>; yields {i32}</i>
4985 %success = <a href="#i_icmp">icmp</a> eq i32 %cmp, %old
4986 <a href="#i_br">br</a> i1 %success, label %done, label %loop
4987
4988done:
4989 ...
4990</pre>
4991
4992</div>
4993
4994<!-- _______________________________________________________________________ -->
NAKAMURA Takumib5bb29c2011-08-12 06:17:17 +0000[diff] [blame]4995<h4>
4996<a name="i_atomicrmw">'<tt>atomicrmw</tt>' Instruction</a>
4997</h4>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]4998
NAKAMURA Takumib5bb29c2011-08-12 06:17:17 +0000[diff] [blame]4999<div>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]5000
5001<h5>Syntax:</h5>
5002<pre>
Eli Friedmanf03bb262011-08-12 22:50:01 +0000[diff] [blame]5003 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]5004</pre>
5005
5006<h5>Overview:</h5>
5007<p>The '<tt>atomicrmw</tt>' instruction is used to atomically modify memory.</p>
5008
5009<h5>Arguments:</h5>
5010<p>There are three arguments to the '<code>atomicrmw</code>' instruction: an
5011operation to apply, an address whose value to modify, an argument to the
5012operation. The operation must be one of the following keywords:</p>
5013<ul>
5014 <li>xchg</li>
5015 <li>add</li>
5016 <li>sub</li>
5017 <li>and</li>
5018 <li>nand</li>
5019 <li>or</li>
5020 <li>xor</li>
5021 <li>max</li>
5022 <li>min</li>
5023 <li>umax</li>
5024 <li>umin</li>
5025</ul>
5026
5027<p>The type of '<var>&lt;value&gt;</var>' must be an integer type whose
5028bit width is a power of two greater than or equal to eight and less than
5029or equal to a target-specific size limit. The type of the
5030'<code>&lt;pointer&gt;</code>' operand must be a pointer to that type.
5031If the <code>atomicrmw</code> is marked as <code>volatile</code>, then the
5032optimizer is not allowed to modify the number or order of execution of this
5033<code>atomicrmw</code> with other <a href="#volatile">volatile
5034 operations</a>.</p>
5035
5036<!-- FIXME: Extend allowed types. -->
5037
5038<h5>Semantics:</h5>
5039<p>The contents of memory at the location specified by the
5040'<tt>&lt;pointer&gt;</tt>' operand are atomically read, modified, and written
5041back. The original value at the location is returned. The modification is
5042specified by the <var>operation</var> argument:</p>
5043
5044<ul>
5045 <li>xchg: <code>*ptr = val</code></li>
5046 <li>add: <code>*ptr = *ptr + val</code></li>
5047 <li>sub: <code>*ptr = *ptr - val</code></li>
5048 <li>and: <code>*ptr = *ptr &amp; val</code></li>
5049 <li>nand: <code>*ptr = ~(*ptr &amp; val)</code></li>
5050 <li>or: <code>*ptr = *ptr | val</code></li>
5051 <li>xor: <code>*ptr = *ptr ^ val</code></li>
5052 <li>max: <code>*ptr = *ptr &gt; val ? *ptr : val</code> (using a signed comparison)</li>
5053 <li>min: <code>*ptr = *ptr &lt; val ? *ptr : val</code> (using a signed comparison)</li>
5054 <li>umax: <code>*ptr = *ptr &gt; val ? *ptr : val</code> (using an unsigned comparison)</li>
5055 <li>umin: <code>*ptr = *ptr &lt; val ? *ptr : val</code> (using an unsigned comparison)</li>
5056</ul>
5057
5058<h5>Example:</h5>
5059<pre>
5060 %old = atomicrmw add i32* %ptr, i32 1 acquire <i>; yields {i32}</i>
5061</pre>
5062
5063</div>
5064
5065<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5066<h4>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5067 <a name="i_getelementptr">'<tt>getelementptr</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5068</h4>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5069
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5070<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5071
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]5072<h5>Syntax:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5073<pre>
Matthijs Kooijmane49d0bc2008-10-13 13:44:15 +0000[diff] [blame]5074 &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]5075 &lt;result&gt; = getelementptr inbounds &lt;pty&gt;* &lt;ptrval&gt;{, &lt;ty&gt; &lt;idx&gt;}*
Nadav Rotem16087692011-12-05 06:29:09 +0000[diff] [blame]5076 &lt;result&gt; = getelementptr &lt;ptr vector&gt; ptrval, &lt;vector index type&gt; idx
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5077</pre>
5078
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]5079<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5080<p>The '<tt>getelementptr</tt>' instruction is used to get the address of a
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]5081 subelement of an <a href="#t_aggregate">aggregate</a> data structure.
5082 It performs address calculation only and does not access memory.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5083
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]5084<h5>Arguments:</h5>
Nadav Rotem16087692011-12-05 06:29:09 +0000[diff] [blame]5085<p>The first argument is always a pointer or a vector of pointers,
5086 and forms the basis of the
Chris Lattnerc8eef442009-07-29 06:44:13 +0000[diff] [blame]5087 calculation. The remaining arguments are indices that indicate which of the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5088 elements of the aggregate object are indexed. The interpretation of each
5089 index is dependent on the type being indexed into. The first index always
5090 indexes the pointer value given as the first argument, the second index
5091 indexes a value of the type pointed to (not necessarily the value directly
5092 pointed to, since the first index can be non-zero), etc. The first type
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]5093 indexed into must be a pointer value, subsequent types can be arrays,
Chris Lattner61c70e92010-08-28 04:09:24 +0000[diff] [blame]5094 vectors, and structs. Note that subsequent types being indexed into
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]5095 can never be pointers, since that would require loading the pointer before
5096 continuing calculation.</p>
Matthijs Kooijmane49d0bc2008-10-13 13:44:15 +0000[diff] [blame]5097
5098<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]5099 When indexing into a (optionally packed) structure, only <tt>i32</tt>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]5100 integer <b>constants</b> are allowed. When indexing into an array, pointer
5101 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]5102 constant. These integers are treated as signed values where relevant.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5103
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5104<p>For example, let's consider a C code fragment and how it gets compiled to
5105 LLVM:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5106
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]5107<pre class="doc_code">
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]5108struct RT {
5109 char A;
Chris Lattnercabc8462007-05-29 15:43:56 +0000[diff] [blame]5110 int B[10][20];
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]5111 char C;
5112};
5113struct ST {
Chris Lattnercabc8462007-05-29 15:43:56 +0000[diff] [blame]5114 int X;
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]5115 double Y;
5116 struct RT Z;
5117};
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5118
Chris Lattnercabc8462007-05-29 15:43:56 +0000[diff] [blame]5119int *foo(struct ST *s) {
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]5120 return &amp;s[1].Z.B[5][13];
5121}
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5122</pre>
5123
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5124<p>The LLVM code generated by the GCC frontend is:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5125
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]5126<pre class="doc_code">
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]5127%RT = <a href="#namedtypes">type</a> { i8 , [10 x [20 x i32]], i8 }
5128%ST = <a href="#namedtypes">type</a> { i32, double, %RT }
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5129
Dan Gohman4df605b2009-07-25 02:23:48 +0000[diff] [blame]5130define i32* @foo(%ST* %s) {
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]5131entry:
5132 %reg = getelementptr %ST* %s, i32 1, i32 2, i32 1, i32 5, i32 13
5133 ret i32* %reg
5134}
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5135</pre>
5136
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]5137<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5138<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]5139 type, which is a pointer, yielding a '<tt>%ST</tt>' = '<tt>{ i32, double, %RT
5140 }</tt>' type, a structure. The second index indexes into the third element
5141 of the structure, yielding a '<tt>%RT</tt>' = '<tt>{ i8 , [10 x [20 x i32]],
5142 i8 }</tt>' type, another structure. The third index indexes into the second
5143 element of the structure, yielding a '<tt>[10 x [20 x i32]]</tt>' type, an
5144 array. The two dimensions of the array are subscripted into, yielding an
5145 '<tt>i32</tt>' type. The '<tt>getelementptr</tt>' instruction returns a
5146 pointer to this element, thus computing a value of '<tt>i32*</tt>' type.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5147
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5148<p>Note that it is perfectly legal to index partially through a structure,
5149 returning a pointer to an inner element. Because of this, the LLVM code for
5150 the given testcase is equivalent to:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5151
5152<pre>
Dan Gohman4df605b2009-07-25 02:23:48 +0000[diff] [blame]5153 define i32* @foo(%ST* %s) {
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5154 %t1 = getelementptr %ST* %s, i32 1 <i>; yields %ST*:%t1</i>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]5155 %t2 = getelementptr %ST* %t1, i32 0, i32 2 <i>; yields %RT*:%t2</i>
5156 %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]5157 %t4 = getelementptr [10 x [20 x i32]]* %t3, i32 0, i32 5 <i>; yields [20 x i32]*:%t4</i>
5158 %t5 = getelementptr [20 x i32]* %t4, i32 0, i32 13 <i>; yields i32*:%t5</i>
5159 ret i32* %t5
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5160 }
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]5161</pre>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]5162
Dan Gohmandd8004d2009-07-27 21:53:46 +0000[diff] [blame]5163<p>If the <tt>inbounds</tt> keyword is present, the result value of the
Dan Gohmanbfb056d2011-12-06 03:18:47 +0000[diff] [blame]5164 <tt>getelementptr</tt> is a <a href="#poisonvalues">poison value</a> if the
Dan Gohman27ef9972010-04-23 15:23:32 +0000[diff] [blame]5165 base pointer is not an <i>in bounds</i> address of an allocated object,
5166 or if any of the addresses that would be formed by successive addition of
5167 the offsets implied by the indices to the base address with infinitely
Eli Friedman266246c2011-08-12 23:37:55 +0000[diff] [blame]5168 precise signed arithmetic are not an <i>in bounds</i> address of that
5169 allocated object. The <i>in bounds</i> addresses for an allocated object
5170 are all the addresses that point into the object, plus the address one
Nadav Rotem16087692011-12-05 06:29:09 +0000[diff] [blame]5171 byte past the end.
5172 In cases where the base is a vector of pointers the <tt>inbounds</tt> keyword
5173 applies to each of the computations element-wise. </p>
Dan Gohmandd8004d2009-07-27 21:53:46 +0000[diff] [blame]5174
5175<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]5176 the base address with silently-wrapping two's complement arithmetic. If the
5177 offsets have a different width from the pointer, they are sign-extended or
5178 truncated to the width of the pointer. The result value of the
5179 <tt>getelementptr</tt> may be outside the object pointed to by the base
5180 pointer. The result value may not necessarily be used to access memory
5181 though, even if it happens to point into allocated storage. See the
5182 <a href="#pointeraliasing">Pointer Aliasing Rules</a> section for more
5183 information.</p>
Dan Gohmandd8004d2009-07-27 21:53:46 +0000[diff] [blame]5184
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5185<p>The getelementptr instruction is often confusing. For some more insight into
5186 how it works, see <a href="GetElementPtr.html">the getelementptr FAQ</a>.</p>
Chris Lattner884a9702006-08-15 00:45:58 +0000[diff] [blame]5187
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]5188<h5>Example:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5189<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5190 <i>; yields [12 x i8]*:aptr</i>
Matthijs Kooijmane49d0bc2008-10-13 13:44:15 +0000[diff] [blame]5191 %aptr = getelementptr {i32, [12 x i8]}* %saptr, i64 0, i32 1
5192 <i>; yields i8*:vptr</i>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]5193 %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]5194 <i>; yields i8*:eptr</i>
5195 %eptr = getelementptr [12 x i8]* %aptr, i64 0, i32 1
Sanjiv Gupta9f805c22009-04-25 07:27:44 +0000[diff] [blame]5196 <i>; yields i32*:iptr</i>
Sanjiv Gupta16ffa802009-04-24 16:38:13 +0000[diff] [blame]5197 %iptr = getelementptr [10 x i32]* @arr, i16 0, i16 0
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5198</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5199
Nadav Rotem16087692011-12-05 06:29:09 +0000[diff] [blame]5200<p>In cases where the pointer argument is a vector of pointers, only a
5201 single index may be used, and the number of vector elements has to be
5202 the same. For example: </p>
5203<pre class="doc_code">
5204 %A = getelementptr <4 x i8*> %ptrs, <4 x i64> %offsets,
5205</pre>
5206
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5207</div>
Reid Spencer47ce1792006-11-09 21:15:49 +0000[diff] [blame]5208
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5209</div>
5210
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]5211<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5212<h3>
5213 <a name="convertops">Conversion Operations</a>
5214</h3>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5215
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5216<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5217
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5218<p>The instructions in this category are the conversion instructions (casting)
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5219 which all take a single operand and a type. They perform various bit
5220 conversions on the operand.</p>
5221
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]5222<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5223<h4>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5224 <a name="i_trunc">'<tt>trunc .. to</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5225</h4>
5226
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5227<div>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5228
5229<h5>Syntax:</h5>
5230<pre>
5231 &lt;result&gt; = trunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
5232</pre>
5233
5234<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5235<p>The '<tt>trunc</tt>' instruction truncates its operand to the
5236 type <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5237
5238<h5>Arguments:</h5>
Nadav Rotem8c20ec52011-02-24 21:01:34 +0000[diff] [blame]5239<p>The '<tt>trunc</tt>' instruction takes a value to trunc, and a type to trunc it to.
5240 Both types must be of <a href="#t_integer">integer</a> types, or vectors
5241 of the same number of integers.
5242 The bit size of the <tt>value</tt> must be larger than
5243 the bit size of the destination type, <tt>ty2</tt>.
5244 Equal sized types are not allowed.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5245
5246<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5247<p>The '<tt>trunc</tt>' instruction truncates the high order bits
5248 in <tt>value</tt> and converts the remaining bits to <tt>ty2</tt>. Since the
5249 source size must be larger than the destination size, <tt>trunc</tt> cannot
5250 be a <i>no-op cast</i>. It will always truncate bits.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5251
5252<h5>Example:</h5>
5253<pre>
Nadav Rotem8c20ec52011-02-24 21:01:34 +0000[diff] [blame]5254 %X = trunc i32 257 to i8 <i>; yields i8:1</i>
5255 %Y = trunc i32 123 to i1 <i>; yields i1:true</i>
5256 %Z = trunc i32 122 to i1 <i>; yields i1:false</i>
5257 %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]5258</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5259
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5260</div>
5261
5262<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5263<h4>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5264 <a name="i_zext">'<tt>zext .. to</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5265</h4>
5266
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5267<div>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5268
5269<h5>Syntax:</h5>
5270<pre>
5271 &lt;result&gt; = zext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
5272</pre>
5273
5274<h5>Overview:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5275<p>The '<tt>zext</tt>' instruction zero extends its operand to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5276 <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5277
5278
5279<h5>Arguments:</h5>
Nadav Rotemed9b9342011-02-20 12:37:50 +0000[diff] [blame]5280<p>The '<tt>zext</tt>' instruction takes a value to cast, and a type to cast it to.
5281 Both types must be of <a href="#t_integer">integer</a> types, or vectors
5282 of the same number of integers.
5283 The bit size of the <tt>value</tt> must be smaller than
5284 the bit size of the destination type,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5285 <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5286
5287<h5>Semantics:</h5>
5288<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]5289 bits until it reaches the size of the destination type, <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5290
Reid Spencerb5929522007-01-12 15:46:11 +0000[diff] [blame]5291<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]5292
5293<h5>Example:</h5>
5294<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5295 %X = zext i32 257 to i64 <i>; yields i64:257</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]5296 %Y = zext i1 true to i32 <i>; yields i32:1</i>
Nadav Rotemed9b9342011-02-20 12:37:50 +0000[diff] [blame]5297 %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]5298</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5299
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5300</div>
5301
5302<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5303<h4>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5304 <a name="i_sext">'<tt>sext .. to</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5305</h4>
5306
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5307<div>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5308
5309<h5>Syntax:</h5>
5310<pre>
5311 &lt;result&gt; = sext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
5312</pre>
5313
5314<h5>Overview:</h5>
5315<p>The '<tt>sext</tt>' sign extends <tt>value</tt> to the type <tt>ty2</tt>.</p>
5316
5317<h5>Arguments:</h5>
Nadav Rotem8c20ec52011-02-24 21:01:34 +0000[diff] [blame]5318<p>The '<tt>sext</tt>' instruction takes a value to cast, and a type to cast it to.
5319 Both types must be of <a href="#t_integer">integer</a> types, or vectors
5320 of the same number of integers.
5321 The bit size of the <tt>value</tt> must be smaller than
5322 the bit size of the destination type,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5323 <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5324
5325<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5326<p>The '<tt>sext</tt>' instruction performs a sign extension by copying the sign
5327 bit (highest order bit) of the <tt>value</tt> until it reaches the bit size
5328 of the type <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5329
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]5330<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]5331
5332<h5>Example:</h5>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5333<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5334 %X = sext i8 -1 to i16 <i>; yields i16 :65535</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]5335 %Y = sext i1 true to i32 <i>; yields i32:-1</i>
Nadav Rotem8c20ec52011-02-24 21:01:34 +0000[diff] [blame]5336 %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]5337</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5338
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5339</div>
5340
5341<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5342<h4>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]5343 <a name="i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5344</h4>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]5345
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5346<div>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]5347
5348<h5>Syntax:</h5>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]5349<pre>
5350 &lt;result&gt; = fptrunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
5351</pre>
5352
5353<h5>Overview:</h5>
5354<p>The '<tt>fptrunc</tt>' instruction truncates <tt>value</tt> to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5355 <tt>ty2</tt>.</p>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]5356
5357<h5>Arguments:</h5>
5358<p>The '<tt>fptrunc</tt>' instruction takes a <a href="#t_floating">floating
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5359 point</a> value to cast and a <a href="#t_floating">floating point</a> type
5360 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]5361 <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]5362 <i>no-op cast</i>.</p>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]5363
5364<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5365<p>The '<tt>fptrunc</tt>' instruction truncates a <tt>value</tt> from a larger
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5366 <a href="#t_floating">floating point</a> type to a smaller
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5367 <a href="#t_floating">floating point</a> type. If the value cannot fit
5368 within the destination type, <tt>ty2</tt>, then the results are
5369 undefined.</p>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]5370
5371<h5>Example:</h5>
5372<pre>
5373 %X = fptrunc double 123.0 to float <i>; yields float:123.0</i>
5374 %Y = fptrunc double 1.0E+300 to float <i>; yields undefined</i>
5375</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5376
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]5377</div>
5378
5379<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5380<h4>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5381 <a name="i_fpext">'<tt>fpext .. to</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5382</h4>
5383
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5384<div>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5385
5386<h5>Syntax:</h5>
5387<pre>
5388 &lt;result&gt; = fpext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
5389</pre>
5390
5391<h5>Overview:</h5>
5392<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]5393 floating point value.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5394
5395<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5396<p>The '<tt>fpext</tt>' instruction takes a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5397 <a href="#t_floating">floating point</a> <tt>value</tt> to cast, and
5398 a <a href="#t_floating">floating point</a> type to cast it to. The source
5399 type must be smaller than the destination type.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5400
5401<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]5402<p>The '<tt>fpext</tt>' instruction extends the <tt>value</tt> from a smaller
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5403 <a href="#t_floating">floating point</a> type to a larger
5404 <a href="#t_floating">floating point</a> type. The <tt>fpext</tt> cannot be
5405 used to make a <i>no-op cast</i> because it always changes bits. Use
5406 <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]5407
5408<h5>Example:</h5>
5409<pre>
Nick Lewycky5bb3ece2011-03-31 18:20:19 +0000[diff] [blame]5410 %X = fpext float 3.125 to double <i>; yields double:3.125000e+00</i>
5411 %Y = fpext double %X to fp128 <i>; yields fp128:0xL00000000000000004000900000000000</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5412</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5413
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5414</div>
5415
5416<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5417<h4>
Reid Spencer24d6da52007-01-21 00:29:26 +0000[diff] [blame]5418 <a name="i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5419</h4>
5420
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5421<div>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5422
5423<h5>Syntax:</h5>
5424<pre>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]5425 &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]5426</pre>
5427
5428<h5>Overview:</h5>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]5429<p>The '<tt>fptoui</tt>' converts a floating point <tt>value</tt> to its
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5430 unsigned integer equivalent of type <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5431
5432<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5433<p>The '<tt>fptoui</tt>' instruction takes a value to cast, which must be a
5434 scalar or vector <a href="#t_floating">floating point</a> value, and a type
5435 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
5436 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
5437 vector integer type with the same number of elements as <tt>ty</tt></p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5438
5439<h5>Semantics:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5440<p>The '<tt>fptoui</tt>' instruction converts its
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5441 <a href="#t_floating">floating point</a> operand into the nearest (rounding
5442 towards zero) unsigned integer value. If the value cannot fit
5443 in <tt>ty2</tt>, the results are undefined.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5444
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5445<h5>Example:</h5>
5446<pre>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]5447 %X = fptoui double 123.0 to i32 <i>; yields i32:123</i>
Chris Lattner88519042007-09-22 03:17:52 +0000[diff] [blame]5448 %Y = fptoui float 1.0E+300 to i1 <i>; yields undefined:1</i>
Gabor Greif6a292012009-10-28 09:21:30 +0000[diff] [blame]5449 %Z = fptoui float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5450</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5451
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5452</div>
5453
5454<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5455<h4>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]5456 <a name="i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5457</h4>
5458
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5459<div>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5460
5461<h5>Syntax:</h5>
5462<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]5463 &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]5464</pre>
5465
5466<h5>Overview:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5467<p>The '<tt>fptosi</tt>' instruction converts
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5468 <a href="#t_floating">floating point</a> <tt>value</tt> to
5469 type <tt>ty2</tt>.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5470
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]5471<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5472<p>The '<tt>fptosi</tt>' instruction takes a value to cast, which must be a
5473 scalar or vector <a href="#t_floating">floating point</a> value, and a type
5474 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
5475 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
5476 vector integer type with the same number of elements as <tt>ty</tt></p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5477
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]5478<h5>Semantics:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5479<p>The '<tt>fptosi</tt>' instruction converts its
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5480 <a href="#t_floating">floating point</a> operand into the nearest (rounding
5481 towards zero) signed integer value. If the value cannot fit in <tt>ty2</tt>,
5482 the results are undefined.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5483
Chris Lattner33ba0d92001-07-09 00:26:23 +0000[diff] [blame]5484<h5>Example:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5485<pre>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]5486 %X = fptosi double -123.0 to i32 <i>; yields i32:-123</i>
Chris Lattner88519042007-09-22 03:17:52 +0000[diff] [blame]5487 %Y = fptosi float 1.0E-247 to i1 <i>; yields undefined:1</i>
Gabor Greif6a292012009-10-28 09:21:30 +0000[diff] [blame]5488 %Z = fptosi float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5489</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5490
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5491</div>
5492
5493<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5494<h4>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]5495 <a name="i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5496</h4>
5497
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5498<div>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5499
5500<h5>Syntax:</h5>
5501<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]5502 &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]5503</pre>
5504
5505<h5>Overview:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]5506<p>The '<tt>uitofp</tt>' instruction regards <tt>value</tt> as an unsigned
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5507 integer and converts that value to the <tt>ty2</tt> type.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5508
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5509<h5>Arguments:</h5>
Nate Begemanb348d182007-11-17 03:58:34 +0000[diff] [blame]5510<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]5511 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
5512 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
5513 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
5514 floating point type with the same number of elements as <tt>ty</tt></p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5515
5516<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]5517<p>The '<tt>uitofp</tt>' instruction interprets its operand as an unsigned
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5518 integer quantity and converts it to the corresponding floating point
5519 value. If the value cannot fit in the floating point value, the results are
5520 undefined.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5521
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5522<h5>Example:</h5>
5523<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5524 %X = uitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]5525 %Y = uitofp i8 -1 to double <i>; yields double:255.0</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5526</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5527
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5528</div>
5529
5530<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5531<h4>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]5532 <a name="i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5533</h4>
5534
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5535<div>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5536
5537<h5>Syntax:</h5>
5538<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]5539 &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]5540</pre>
5541
5542<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5543<p>The '<tt>sitofp</tt>' instruction regards <tt>value</tt> as a signed integer
5544 and converts that value to the <tt>ty2</tt> type.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5545
5546<h5>Arguments:</h5>
Nate Begemanb348d182007-11-17 03:58:34 +0000[diff] [blame]5547<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]5548 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
5549 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
5550 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
5551 floating point type with the same number of elements as <tt>ty</tt></p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5552
5553<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5554<p>The '<tt>sitofp</tt>' instruction interprets its operand as a signed integer
5555 quantity and converts it to the corresponding floating point value. If the
5556 value cannot fit in the floating point value, the results are undefined.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5557
5558<h5>Example:</h5>
5559<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5560 %X = sitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]5561 %Y = sitofp i8 -1 to double <i>; yields double:-1.0</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5562</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5563
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5564</div>
5565
5566<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5567<h4>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]5568 <a name="i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5569</h4>
5570
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5571<div>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]5572
5573<h5>Syntax:</h5>
5574<pre>
5575 &lt;result&gt; = ptrtoint &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
5576</pre>
5577
5578<h5>Overview:</h5>
Nadav Rotem16087692011-12-05 06:29:09 +0000[diff] [blame]5579<p>The '<tt>ptrtoint</tt>' instruction converts the pointer or a vector of
5580 pointers <tt>value</tt> to
5581 the integer (or vector of integers) type <tt>ty2</tt>.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]5582
5583<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5584<p>The '<tt>ptrtoint</tt>' instruction takes a <tt>value</tt> to cast, which
Nadav Rotem16087692011-12-05 06:29:09 +0000[diff] [blame]5585 must be a a value of type <a href="#t_pointer">pointer</a> or a vector of
5586 pointers, and a type to cast it to
5587 <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a> or a vector
5588 of integers type.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]5589
5590<h5>Semantics:</h5>
5591<p>The '<tt>ptrtoint</tt>' instruction converts <tt>value</tt> to integer type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5592 <tt>ty2</tt> by interpreting the pointer value as an integer and either
5593 truncating or zero extending that value to the size of the integer type. If
5594 <tt>value</tt> is smaller than <tt>ty2</tt> then a zero extension is done. If
5595 <tt>value</tt> is larger than <tt>ty2</tt> then a truncation is done. If they
5596 are the same size, then nothing is done (<i>no-op cast</i>) other than a type
5597 change.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]5598
5599<h5>Example:</h5>
5600<pre>
Nadav Rotem16087692011-12-05 06:29:09 +0000[diff] [blame]5601 %X = ptrtoint i32* %P to i8 <i>; yields truncation on 32-bit architecture</i>
5602 %Y = ptrtoint i32* %P to i64 <i>; yields zero extension on 32-bit architecture</i>
5603 %Z = ptrtoint &lt;4 x i32*&gt; %P to &lt;4 x i64&gt;<i>; yields vector zero extension for a vector of addresses on 32-bit architecture</i>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]5604</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5605
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]5606</div>
5607
5608<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5609<h4>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]5610 <a name="i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5611</h4>
5612
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5613<div>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]5614
5615<h5>Syntax:</h5>
5616<pre>
5617 &lt;result&gt; = inttoptr &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
5618</pre>
5619
5620<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5621<p>The '<tt>inttoptr</tt>' instruction converts an integer <tt>value</tt> to a
5622 pointer type, <tt>ty2</tt>.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]5623
5624<h5>Arguments:</h5>
Duncan Sands8036ca42007-03-30 12:22:09 +0000[diff] [blame]5625<p>The '<tt>inttoptr</tt>' instruction takes an <a href="#t_integer">integer</a>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5626 value to cast, and a type to cast it to, which must be a
5627 <a href="#t_pointer">pointer</a> type.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]5628
5629<h5>Semantics:</h5>
5630<p>The '<tt>inttoptr</tt>' instruction converts <tt>value</tt> to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5631 <tt>ty2</tt> by applying either a zero extension or a truncation depending on
5632 the size of the integer <tt>value</tt>. If <tt>value</tt> is larger than the
5633 size of a pointer then a truncation is done. If <tt>value</tt> is smaller
5634 than the size of a pointer then a zero extension is done. If they are the
5635 same size, nothing is done (<i>no-op cast</i>).</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]5636
5637<h5>Example:</h5>
5638<pre>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5639 %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]5640 %Y = inttoptr i32 255 to i32* <i>; yields no-op on 32-bit architecture</i>
5641 %Z = inttoptr i64 0 to i32* <i>; yields truncation on 32-bit architecture</i>
Nadav Rotem16087692011-12-05 06:29:09 +0000[diff] [blame]5642 %Z = inttoptr &lt;4 x i32&gt; %G to &lt;4 x i8*&gt;<i>; yields truncation of vector G to four pointers</i>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]5643</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5644
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]5645</div>
5646
5647<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5648<h4>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]5649 <a name="i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5650</h4>
5651
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5652<div>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5653
5654<h5>Syntax:</h5>
5655<pre>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]5656 &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]5657</pre>
5658
5659<h5>Overview:</h5>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]5660<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5661 <tt>ty2</tt> without changing any bits.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5662
5663<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5664<p>The '<tt>bitcast</tt>' instruction takes a value to cast, which must be a
5665 non-aggregate first class value, and a type to cast it to, which must also be
5666 a non-aggregate <a href="#t_firstclass">first class</a> type. The bit sizes
5667 of <tt>value</tt> and the destination type, <tt>ty2</tt>, must be
5668 identical. If the source type is a pointer, the destination type must also be
5669 a pointer. This instruction supports bitwise conversion of vectors to
5670 integers and to vectors of other types (as long as they have the same
5671 size).</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5672
5673<h5>Semantics:</h5>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]5674<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5675 <tt>ty2</tt>. It is always a <i>no-op cast</i> because no bits change with
5676 this conversion. The conversion is done as if the <tt>value</tt> had been
Nadav Rotem16087692011-12-05 06:29:09 +0000[diff] [blame]5677 stored to memory and read back as type <tt>ty2</tt>.
5678 Pointer (or vector of pointers) types may only be converted to other pointer
5679 (or vector of pointers) types with this instruction. To convert
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5680 pointers to other types, use the <a href="#i_inttoptr">inttoptr</a> or
5681 <a href="#i_ptrtoint">ptrtoint</a> instructions first.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5682
5683<h5>Example:</h5>
5684<pre>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5685 %X = bitcast i8 255 to i8 <i>; yields i8 :-1</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5686 %Y = bitcast i32* %x to sint* <i>; yields sint*:%x</i>
Nadav Rotem16087692011-12-05 06:29:09 +0000[diff] [blame]5687 %Z = bitcast &lt;2 x int&gt; %V to i64; <i>; yields i64: %V</i>
5688 %Z = bitcast &lt;2 x i32*&gt; %V to &lt;2 x i64*&gt; <i>; yields &lt;2 x i64*&gt;</i>
Chris Lattner33ba0d92001-07-09 00:26:23 +0000[diff] [blame]5689</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5690
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5691</div>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5692
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5693</div>
5694
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5695<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5696<h3>
5697 <a name="otherops">Other Operations</a>
5698</h3>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5699
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5700<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5701
5702<p>The instructions in this category are the "miscellaneous" instructions, which
5703 defy better classification.</p>
5704
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5705<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5706<h4>
5707 <a name="i_icmp">'<tt>icmp</tt>' Instruction</a>
5708</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5709
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5710<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5711
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5712<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5713<pre>
5714 &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]5715</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5716
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5717<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5718<p>The '<tt>icmp</tt>' instruction returns a boolean value or a vector of
Nadav Rotem16087692011-12-05 06:29:09 +0000[diff] [blame]5719 boolean values based on comparison of its two integer, integer vector,
5720 pointer, or pointer vector operands.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5721
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5722<h5>Arguments:</h5>
5723<p>The '<tt>icmp</tt>' instruction takes three operands. The first operand is
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5724 the condition code indicating the kind of comparison to perform. It is not a
5725 value, just a keyword. The possible condition code are:</p>
5726
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5727<ol>
5728 <li><tt>eq</tt>: equal</li>
5729 <li><tt>ne</tt>: not equal </li>
5730 <li><tt>ugt</tt>: unsigned greater than</li>
5731 <li><tt>uge</tt>: unsigned greater or equal</li>
5732 <li><tt>ult</tt>: unsigned less than</li>
5733 <li><tt>ule</tt>: unsigned less or equal</li>
5734 <li><tt>sgt</tt>: signed greater than</li>
5735 <li><tt>sge</tt>: signed greater or equal</li>
5736 <li><tt>slt</tt>: signed less than</li>
5737 <li><tt>sle</tt>: signed less or equal</li>
5738</ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5739
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]5740<p>The remaining two arguments must be <a href="#t_integer">integer</a> or
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5741 <a href="#t_pointer">pointer</a> or integer <a href="#t_vector">vector</a>
5742 typed. They must also be identical types.</p>
5743
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5744<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5745<p>The '<tt>icmp</tt>' compares <tt>op1</tt> and <tt>op2</tt> according to the
5746 condition code given as <tt>cond</tt>. The comparison performed always yields
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]5747 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]5748 result, as follows:</p>
5749
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5750<ol>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5751 <li><tt>eq</tt>: yields <tt>true</tt> if the operands are equal,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5752 <tt>false</tt> otherwise. No sign interpretation is necessary or
5753 performed.</li>
5754
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5755 <li><tt>ne</tt>: yields <tt>true</tt> if the operands are unequal,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5756 <tt>false</tt> otherwise. No sign interpretation is necessary or
5757 performed.</li>
5758
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5759 <li><tt>ugt</tt>: interprets the operands as unsigned values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5760 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
5761
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5762 <li><tt>uge</tt>: interprets the operands as unsigned values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5763 <tt>true</tt> if <tt>op1</tt> is greater than or equal
5764 to <tt>op2</tt>.</li>
5765
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5766 <li><tt>ult</tt>: interprets the operands as unsigned values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5767 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
5768
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5769 <li><tt>ule</tt>: interprets the operands as unsigned values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5770 <tt>true</tt> if <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
5771
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5772 <li><tt>sgt</tt>: interprets the operands as signed values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5773 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
5774
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5775 <li><tt>sge</tt>: interprets the operands as signed values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5776 <tt>true</tt> if <tt>op1</tt> is greater than or equal
5777 to <tt>op2</tt>.</li>
5778
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5779 <li><tt>slt</tt>: interprets the operands as signed values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5780 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
5781
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5782 <li><tt>sle</tt>: interprets the operands as signed values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5783 <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]5784</ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5785
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5786<p>If the operands are <a href="#t_pointer">pointer</a> typed, the pointer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5787 values are compared as if they were integers.</p>
5788
5789<p>If the operands are integer vectors, then they are compared element by
5790 element. The result is an <tt>i1</tt> vector with the same number of elements
5791 as the values being compared. Otherwise, the result is an <tt>i1</tt>.</p>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5792
5793<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5794<pre>
5795 &lt;result&gt; = icmp eq i32 4, 5 <i>; yields: result=false</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5796 &lt;result&gt; = icmp ne float* %X, %X <i>; yields: result=false</i>
5797 &lt;result&gt; = icmp ult i16 4, 5 <i>; yields: result=true</i>
5798 &lt;result&gt; = icmp sgt i16 4, 5 <i>; yields: result=false</i>
5799 &lt;result&gt; = icmp ule i16 -4, 5 <i>; yields: result=false</i>
5800 &lt;result&gt; = icmp sge i16 4, 5 <i>; yields: result=false</i>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5801</pre>
Dan Gohmanc766f722009-01-22 01:39:38 +0000[diff] [blame]5802
5803<p>Note that the code generator does not yet support vector types with
5804 the <tt>icmp</tt> instruction.</p>
5805
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5806</div>
5807
5808<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5809<h4>
5810 <a name="i_fcmp">'<tt>fcmp</tt>' Instruction</a>
5811</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5812
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5813<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5814
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5815<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5816<pre>
5817 &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]5818</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5819
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5820<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5821<p>The '<tt>fcmp</tt>' instruction returns a boolean value or vector of boolean
5822 values based on comparison of its operands.</p>
5823
5824<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]5825(<a href="#t_integer"><tt>i1</tt></a>).</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5826
5827<p>If the operands are floating point vectors, then the result type is a vector
5828 of boolean with the same number of elements as the operands being
5829 compared.</p>
5830
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5831<h5>Arguments:</h5>
5832<p>The '<tt>fcmp</tt>' instruction takes three operands. The first operand is
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5833 the condition code indicating the kind of comparison to perform. It is not a
5834 value, just a keyword. The possible condition code are:</p>
5835
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5836<ol>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]5837 <li><tt>false</tt>: no comparison, always returns false</li>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5838 <li><tt>oeq</tt>: ordered and equal</li>
5839 <li><tt>ogt</tt>: ordered and greater than </li>
5840 <li><tt>oge</tt>: ordered and greater than or equal</li>
5841 <li><tt>olt</tt>: ordered and less than </li>
5842 <li><tt>ole</tt>: ordered and less than or equal</li>
5843 <li><tt>one</tt>: ordered and not equal</li>
5844 <li><tt>ord</tt>: ordered (no nans)</li>
5845 <li><tt>ueq</tt>: unordered or equal</li>
5846 <li><tt>ugt</tt>: unordered or greater than </li>
5847 <li><tt>uge</tt>: unordered or greater than or equal</li>
5848 <li><tt>ult</tt>: unordered or less than </li>
5849 <li><tt>ule</tt>: unordered or less than or equal</li>
5850 <li><tt>une</tt>: unordered or not equal</li>
5851 <li><tt>uno</tt>: unordered (either nans)</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]5852 <li><tt>true</tt>: no comparison, always returns true</li>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5853</ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5854
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5855<p><i>Ordered</i> means that neither operand is a QNAN while
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5856 <i>unordered</i> means that either operand may be a QNAN.</p>
5857
5858<p>Each of <tt>val1</tt> and <tt>val2</tt> arguments must be either
5859 a <a href="#t_floating">floating point</a> type or
5860 a <a href="#t_vector">vector</a> of floating point type. They must have
5861 identical types.</p>
5862
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5863<h5>Semantics:</h5>
Gabor Greiffb224a22008-08-07 21:46:00 +0000[diff] [blame]5864<p>The '<tt>fcmp</tt>' instruction compares <tt>op1</tt> and <tt>op2</tt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5865 according to the condition code given as <tt>cond</tt>. If the operands are
5866 vectors, then the vectors are compared element by element. Each comparison
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]5867 performed always yields an <a href="#t_integer">i1</a> result, as
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5868 follows:</p>
5869
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5870<ol>
5871 <li><tt>false</tt>: always yields <tt>false</tt>, regardless of operands.</li>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5872
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5873 <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]5874 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
5875
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]5876 <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]5877 <tt>op1</tt> is greater than <tt>op2</tt>.</li>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5878
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5879 <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]5880 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
5881
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5882 <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]5883 <tt>op1</tt> is less than <tt>op2</tt>.</li>
5884
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5885 <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]5886 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
5887
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5888 <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]5889 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
5890
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]5891 <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]5892
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5893 <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]5894 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
5895
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5896 <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]5897 <tt>op1</tt> is greater than <tt>op2</tt>.</li>
5898
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5899 <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]5900 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
5901
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5902 <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]5903 <tt>op1</tt> is less than <tt>op2</tt>.</li>
5904
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5905 <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]5906 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
5907
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5908 <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]5909 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
5910
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]5911 <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]5912
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5913 <li><tt>true</tt>: always yields <tt>true</tt>, regardless of operands.</li>
5914</ol>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5915
5916<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5917<pre>
5918 &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]5919 &lt;result&gt; = fcmp one float 4.0, 5.0 <i>; yields: result=true</i>
5920 &lt;result&gt; = fcmp olt float 4.0, 5.0 <i>; yields: result=true</i>
5921 &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]5922</pre>
Dan Gohmanc766f722009-01-22 01:39:38 +0000[diff] [blame]5923
5924<p>Note that the code generator does not yet support vector types with
5925 the <tt>fcmp</tt> instruction.</p>
5926
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5927</div>
5928
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5929<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5930<h4>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5931 <a name="i_phi">'<tt>phi</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5932</h4>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5933
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5934<div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5935
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5936<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5937<pre>
5938 &lt;result&gt; = phi &lt;ty&gt; [ &lt;val0&gt;, &lt;label0&gt;], ...
5939</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5940
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5941<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5942<p>The '<tt>phi</tt>' instruction is used to implement the &#966; node in the
5943 SSA graph representing the function.</p>
5944
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5945<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5946<p>The type of the incoming values is specified with the first type field. After
5947 this, the '<tt>phi</tt>' instruction takes a list of pairs as arguments, with
5948 one pair for each predecessor basic block of the current block. Only values
5949 of <a href="#t_firstclass">first class</a> type may be used as the value
5950 arguments to the PHI node. Only labels may be used as the label
5951 arguments.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5952
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5953<p>There must be no non-phi instructions between the start of a basic block and
5954 the PHI instructions: i.e. PHI instructions must be first in a basic
5955 block.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5956
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5957<p>For the purposes of the SSA form, the use of each incoming value is deemed to
5958 occur on the edge from the corresponding predecessor block to the current
5959 block (but after any definition of an '<tt>invoke</tt>' instruction's return
5960 value on the same edge).</p>
Jay Foadd2449092009-06-03 10:20:10 +0000[diff] [blame]5961
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5962<h5>Semantics:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5963<p>At runtime, the '<tt>phi</tt>' instruction logically takes on the value
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5964 specified by the pair corresponding to the predecessor basic block that
5965 executed just prior to the current block.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5966
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5967<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5968<pre>
5969Loop: ; Infinite loop that counts from 0 on up...
5970 %indvar = phi i32 [ 0, %LoopHeader ], [ %nextindvar, %Loop ]
5971 %nextindvar = add i32 %indvar, 1
5972 br label %Loop
5973</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5974
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5975</div>
5976
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5977<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5978<h4>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5979 <a name="i_select">'<tt>select</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5980</h4>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5981
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5982<div>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5983
5984<h5>Syntax:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5985<pre>
Dan Gohmanf72fb672008-09-09 01:02:47 +0000[diff] [blame]5986 &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>
5987
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]5988 <i>selty</i> is either i1 or {&lt;N x i1&gt;}
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5989</pre>
5990
5991<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5992<p>The '<tt>select</tt>' instruction is used to choose one value based on a
5993 condition, without branching.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5994
5995
5996<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5997<p>The '<tt>select</tt>' instruction requires an 'i1' value or a vector of 'i1'
5998 values indicating the condition, and two values of the
5999 same <a href="#t_firstclass">first class</a> type. If the val1/val2 are
6000 vectors and the condition is a scalar, then entire vectors are selected, not
6001 individual elements.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]6002
6003<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6004<p>If the condition is an i1 and it evaluates to 1, the instruction returns the
6005 first value argument; otherwise, it returns the second value argument.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]6006
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6007<p>If the condition is a vector of i1, then the value arguments must be vectors
6008 of the same size, and the selection is done element by element.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]6009
6010<h5>Example:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]6011<pre>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]6012 %X = select i1 true, i8 17, i8 42 <i>; yields i8:17</i>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]6013</pre>
Dan Gohmanc766f722009-01-22 01:39:38 +0000[diff] [blame]6014
6015<p>Note that the code generator does not yet support conditions
6016 with vector type.</p>
6017
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]6018</div>
6019
Robert Bocchino05ccd702006-01-15 20:48:27 +0000[diff] [blame]6020<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6021<h4>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]6022 <a name="i_call">'<tt>call</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6023</h4>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]6024
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6025<div>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]6026
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]6027<h5>Syntax:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]6028<pre>
Devang Patel307e8ab2008-10-07 17:48:33 +0000[diff] [blame]6029 &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]6030</pre>
6031
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]6032<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]6033<p>The '<tt>call</tt>' instruction represents a simple function call.</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]6034
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]6035<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]6036<p>This instruction requires several arguments:</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]6037
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]6038<ol>
Jeffrey Yasskin95fa80a2010-01-09 19:44:16 +0000[diff] [blame]6039 <li>The optional "tail" marker indicates that the callee function does not
6040 access any allocas or varargs in the caller. Note that calls may be
6041 marked "tail" even if they do not occur before
6042 a <a href="#i_ret"><tt>ret</tt></a> instruction. If the "tail" marker is
6043 present, the function call is eligible for tail call optimization,
6044 but <a href="CodeGenerator.html#tailcallopt">might not in fact be
Evan Chengdc444e92010-03-08 21:05:02 +0000[diff] [blame]6045 optimized into a jump</a>. The code generator may optimize calls marked
6046 "tail" with either 1) automatic <a href="CodeGenerator.html#sibcallopt">
6047 sibling call optimization</a> when the caller and callee have
6048 matching signatures, or 2) forced tail call optimization when the
6049 following extra requirements are met:
Jeffrey Yasskin95fa80a2010-01-09 19:44:16 +0000[diff] [blame]6050 <ul>
6051 <li>Caller and callee both have the calling
6052 convention <tt>fastcc</tt>.</li>
6053 <li>The call is in tail position (ret immediately follows call and ret
6054 uses value of call or is void).</li>
6055 <li>Option <tt>-tailcallopt</tt> is enabled,
Dan Gohmanfbbee8d2010-03-02 01:08:11 +0000[diff] [blame]6056 or <code>llvm::GuaranteedTailCallOpt</code> is <code>true</code>.</li>
Jeffrey Yasskin95fa80a2010-01-09 19:44:16 +0000[diff] [blame]6057 <li><a href="CodeGenerator.html#tailcallopt">Platform specific
6058 constraints are met.</a></li>
6059 </ul>
6060 </li>
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]6061
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6062 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
6063 convention</a> the call should use. If none is specified, the call
Jeffrey Yasskin95fa80a2010-01-09 19:44:16 +0000[diff] [blame]6064 defaults to using C calling conventions. The calling convention of the
6065 call must match the calling convention of the target function, or else the
6066 behavior is undefined.</li>
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]6067
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6068 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
6069 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
6070 '<tt>inreg</tt>' attributes are valid here.</li>
6071
6072 <li>'<tt>ty</tt>': the type of the call instruction itself which is also the
6073 type of the return value. Functions that return no value are marked
6074 <tt><a href="#t_void">void</a></tt>.</li>
6075
6076 <li>'<tt>fnty</tt>': shall be the signature of the pointer to function value
6077 being invoked. The argument types must match the types implied by this
6078 signature. This type can be omitted if the function is not varargs and if
6079 the function type does not return a pointer to a function.</li>
6080
6081 <li>'<tt>fnptrval</tt>': An LLVM value containing a pointer to a function to
6082 be invoked. In most cases, this is a direct function invocation, but
6083 indirect <tt>call</tt>s are just as possible, calling an arbitrary pointer
6084 to function value.</li>
6085
6086 <li>'<tt>function args</tt>': argument list whose types match the function
Chris Lattner0724fbd2010-03-02 06:36:51 +0000[diff] [blame]6087 signature argument types and parameter attributes. All arguments must be
6088 of <a href="#t_firstclass">first class</a> type. If the function
6089 signature indicates the function accepts a variable number of arguments,
6090 the extra arguments can be specified.</li>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6091
6092 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
6093 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
6094 '<tt>readnone</tt>' attributes are valid here.</li>
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]6095</ol>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]6096
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]6097<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6098<p>The '<tt>call</tt>' instruction is used to cause control flow to transfer to
6099 a specified function, with its incoming arguments bound to the specified
6100 values. Upon a '<tt><a href="#i_ret">ret</a></tt>' instruction in the called
6101 function, control flow continues with the instruction after the function
6102 call, and the return value of the function is bound to the result
6103 argument.</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]6104
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]6105<h5>Example:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]6106<pre>
Nick Lewyckydb7e3c92007-09-08 13:57:50 +0000[diff] [blame]6107 %retval = call i32 @test(i32 %argc)
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]6108 call i32 (i8*, ...)* @printf(i8* %msg, i32 12, i8 42) <i>; yields i32</i>
Chris Lattner772fccf2008-03-21 17:24:17 +0000[diff] [blame]6109 %X = tail call i32 @foo() <i>; yields i32</i>
6110 %Y = tail call <a href="#callingconv">fastcc</a> i32 @foo() <i>; yields i32</i>
6111 call void %foo(i8 97 signext)
Devang Patelc3fc6df2008-03-10 20:49:15 +0000[diff] [blame]6112
6113 %struct.A = type { i32, i8 }
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]6114 %r = call %struct.A @foo() <i>; yields { 32, i8 }</i>
Dan Gohmanb1e6b962008-10-04 19:00:07 +0000[diff] [blame]6115 %gr = extractvalue %struct.A %r, 0 <i>; yields i32</i>
6116 %gr1 = extractvalue %struct.A %r, 1 <i>; yields i8</i>
Chris Lattner85a350f2008-10-08 06:26:11 +0000[diff] [blame]6117 %Z = call void @foo() noreturn <i>; indicates that %foo never returns normally</i>
Matthijs Kooijmancb73d192008-10-07 10:03:45 +0000[diff] [blame]6118 %ZZ = call zeroext i32 @bar() <i>; Return value is %zero extended</i>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]6119</pre>
6120
Dale Johannesen07de8d12009-09-24 18:38:21 +0000[diff] [blame]6121<p>llvm treats calls to some functions with names and arguments that match the
Dale Johannesen9f8380b2009-09-25 17:04:42 +0000[diff] [blame]6122standard C99 library as being the C99 library functions, and may perform
6123optimizations or generate code for them under that assumption. This is
6124something we'd like to change in the future to provide better support for
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]6125freestanding environments and non-C-based languages.</p>
Dale Johannesen07de8d12009-09-24 18:38:21 +0000[diff] [blame]6126
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]6127</div>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]6128
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6129<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6130<h4>
Chris Lattnerfb6977d2006-01-13 23:26:01 +0000[diff] [blame]6131 <a name="i_va_arg">'<tt>va_arg</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6132</h4>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]6133
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6134<div>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]6135
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]6136<h5>Syntax:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]6137<pre>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]6138 &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]6139</pre>
6140
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]6141<h5>Overview:</h5>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]6142<p>The '<tt>va_arg</tt>' instruction is used to access arguments passed through
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6143 the "variable argument" area of a function call. It is used to implement the
6144 <tt>va_arg</tt> macro in C.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]6145
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]6146<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6147<p>This instruction takes a <tt>va_list*</tt> value and the type of the
6148 argument. It returns a value of the specified argument type and increments
6149 the <tt>va_list</tt> to point to the next argument. The actual type
6150 of <tt>va_list</tt> is target specific.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]6151
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]6152<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6153<p>The '<tt>va_arg</tt>' instruction loads an argument of the specified type
6154 from the specified <tt>va_list</tt> and causes the <tt>va_list</tt> to point
6155 to the next argument. For more information, see the variable argument
6156 handling <a href="#int_varargs">Intrinsic Functions</a>.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]6157
6158<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]6159 take a variable number of arguments, for example, the <tt>vfprintf</tt>
6160 function.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]6161
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6162<p><tt>va_arg</tt> is an LLVM instruction instead of
6163 an <a href="#intrinsics">intrinsic function</a> because it takes a type as an
6164 argument.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]6165
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]6166<h5>Example:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]6167<p>See the <a href="#int_varargs">variable argument processing</a> section.</p>
6168
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6169<p>Note that the code generator does not yet fully support va_arg on many
6170 targets. Also, it does not currently support va_arg with aggregate types on
6171 any target.</p>
Dan Gohmanf3e60bd2009-01-12 23:12:39 +0000[diff] [blame]6172
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]6173</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6174
Bill Wendlingf78faf82011-08-02 21:52:38 +0000[diff] [blame]6175<!-- _______________________________________________________________________ -->
6176<h4>
6177 <a name="i_landingpad">'<tt>landingpad</tt>' Instruction</a>
6178</h4>
6179
6180<div>
6181
6182<h5>Syntax:</h5>
6183<pre>
Bill Wendlingbf13ee12011-08-08 08:06:05 +0000[diff] [blame]6184 &lt;resultval&gt; = landingpad &lt;somety&gt; personality &lt;type&gt; &lt;pers_fn&gt; &lt;clause&gt;+
6185 &lt;resultval&gt; = landingpad &lt;somety&gt; personality &lt;type&gt; &lt;pers_fn&gt; cleanup &lt;clause&gt;*
6186
Bill Wendlingf78faf82011-08-02 21:52:38 +0000[diff] [blame]6187 &lt;clause&gt; := catch &lt;type&gt; &lt;value&gt;
Bill Wendlinge6e88262011-08-12 20:24:12 +0000[diff] [blame]6188 &lt;clause&gt; := filter &lt;array constant type&gt; &lt;array constant&gt;
Bill Wendlingf78faf82011-08-02 21:52:38 +0000[diff] [blame]6189</pre>
6190
6191<h5>Overview:</h5>
6192<p>The '<tt>landingpad</tt>' instruction is used by
6193 <a href="ExceptionHandling.html#overview">LLVM's exception handling
6194 system</a> to specify that a basic block is a landing pad &mdash; one where
6195 the exception lands, and corresponds to the code found in the
6196 <i><tt>catch</tt></i> portion of a <i><tt>try/catch</tt></i> sequence. It
6197 defines values supplied by the personality function (<tt>pers_fn</tt>) upon
6198 re-entry to the function. The <tt>resultval</tt> has the
6199 type <tt>somety</tt>.</p>
6200
6201<h5>Arguments:</h5>
6202<p>This instruction takes a <tt>pers_fn</tt> value. This is the personality
6203 function associated with the unwinding mechanism. The optional
6204 <tt>cleanup</tt> flag indicates that the landing pad block is a cleanup.</p>
6205
6206<p>A <tt>clause</tt> begins with the clause type &mdash; <tt>catch</tt>
Bill Wendlinge6e88262011-08-12 20:24:12 +0000[diff] [blame]6207 or <tt>filter</tt> &mdash; and contains the global variable representing the
6208 "type" that may be caught or filtered respectively. Unlike the
6209 <tt>catch</tt> clause, the <tt>filter</tt> clause takes an array constant as
6210 its argument. Use "<tt>[0 x i8**] undef</tt>" for a filter which cannot
6211 throw. The '<tt>landingpad</tt>' instruction must contain <em>at least</em>
Bill Wendlingf78faf82011-08-02 21:52:38 +0000[diff] [blame]6212 one <tt>clause</tt> or the <tt>cleanup</tt> flag.</p>
6213
6214<h5>Semantics:</h5>
6215<p>The '<tt>landingpad</tt>' instruction defines the values which are set by the
6216 personality function (<tt>pers_fn</tt>) upon re-entry to the function, and
6217 therefore the "result type" of the <tt>landingpad</tt> instruction. As with
6218 calling conventions, how the personality function results are represented in
6219 LLVM IR is target specific.</p>
6220
Bill Wendlingb7a01352011-08-03 17:17:06 +0000[diff] [blame]6221<p>The clauses are applied in order from top to bottom. If two
6222 <tt>landingpad</tt> instructions are merged together through inlining, the
Bill Wendling2905c322011-08-08 07:58:58 +0000[diff] [blame]6223 clauses from the calling function are appended to the list of clauses.</p>
Bill Wendlingb7a01352011-08-03 17:17:06 +0000[diff] [blame]6224
Bill Wendlingf78faf82011-08-02 21:52:38 +0000[diff] [blame]6225<p>The <tt>landingpad</tt> instruction has several restrictions:</p>
6226
6227<ul>
6228 <li>A landing pad block is a basic block which is the unwind destination of an
6229 '<tt>invoke</tt>' instruction.</li>
6230 <li>A landing pad block must have a '<tt>landingpad</tt>' instruction as its
6231 first non-PHI instruction.</li>
6232 <li>There can be only one '<tt>landingpad</tt>' instruction within the landing
6233 pad block.</li>
6234 <li>A basic block that is not a landing pad block may not include a
6235 '<tt>landingpad</tt>' instruction.</li>
6236 <li>All '<tt>landingpad</tt>' instructions in a function must have the same
6237 personality function.</li>
6238</ul>
6239
6240<h5>Example:</h5>
6241<pre>
6242 ;; A landing pad which can catch an integer.
6243 %res = landingpad { i8*, i32 } personality i32 (...)* @__gxx_personality_v0
6244 catch i8** @_ZTIi
6245 ;; A landing pad that is a cleanup.
6246 %res = landingpad { i8*, i32 } personality i32 (...)* @__gxx_personality_v0
Bill Wendlinge6e88262011-08-12 20:24:12 +0000[diff] [blame]6247 cleanup
Bill Wendlingf78faf82011-08-02 21:52:38 +0000[diff] [blame]6248 ;; A landing pad which can catch an integer and can only throw a double.
6249 %res = landingpad { i8*, i32 } personality i32 (...)* @__gxx_personality_v0
6250 catch i8** @_ZTIi
Bill Wendlinge6e88262011-08-12 20:24:12 +0000[diff] [blame]6251 filter [1 x i8**] [@_ZTId]
Bill Wendlingf78faf82011-08-02 21:52:38 +0000[diff] [blame]6252</pre>
6253
6254</div>
6255
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6256</div>
6257
6258</div>
6259
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6260<!-- *********************************************************************** -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6261<h2><a name="intrinsics">Intrinsic Functions</a></h2>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]6262<!-- *********************************************************************** -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6263
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6264<div>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6265
6266<p>LLVM supports the notion of an "intrinsic function". These functions have
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6267 well known names and semantics and are required to follow certain
6268 restrictions. Overall, these intrinsics represent an extension mechanism for
6269 the LLVM language that does not require changing all of the transformations
6270 in LLVM when adding to the language (or the bitcode reader/writer, the
6271 parser, etc...).</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6272
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]6273<p>Intrinsic function names must all start with an "<tt>llvm.</tt>" prefix. This
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6274 prefix is reserved in LLVM for intrinsic names; thus, function names may not
6275 begin with this prefix. Intrinsic functions must always be external
6276 functions: you cannot define the body of intrinsic functions. Intrinsic
6277 functions may only be used in call or invoke instructions: it is illegal to
6278 take the address of an intrinsic function. Additionally, because intrinsic
6279 functions are part of the LLVM language, it is required if any are added that
6280 they be documented here.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6281
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6282<p>Some intrinsic functions can be overloaded, i.e., the intrinsic represents a
6283 family of functions that perform the same operation but on different data
6284 types. Because LLVM can represent over 8 million different integer types,
6285 overloading is used commonly to allow an intrinsic function to operate on any
6286 integer type. One or more of the argument types or the result type can be
6287 overloaded to accept any integer type. Argument types may also be defined as
6288 exactly matching a previous argument's type or the result type. This allows
6289 an intrinsic function which accepts multiple arguments, but needs all of them
6290 to be of the same type, to only be overloaded with respect to a single
6291 argument or the result.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6292
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6293<p>Overloaded intrinsics will have the names of its overloaded argument types
6294 encoded into its function name, each preceded by a period. Only those types
6295 which are overloaded result in a name suffix. Arguments whose type is matched
6296 against another type do not. For example, the <tt>llvm.ctpop</tt> function
6297 can take an integer of any width and returns an integer of exactly the same
6298 integer width. This leads to a family of functions such as
6299 <tt>i8 @llvm.ctpop.i8(i8 %val)</tt> and <tt>i29 @llvm.ctpop.i29(i29
6300 %val)</tt>. Only one type, the return type, is overloaded, and only one type
6301 suffix is required. Because the argument's type is matched against the return
6302 type, it does not require its own name suffix.</p>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]6303
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]6304<p>To learn how to add an intrinsic function, please see the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6305 <a href="ExtendingLLVM.html">Extending LLVM Guide</a>.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6306
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6307<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6308<h3>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6309 <a name="int_varargs">Variable Argument Handling Intrinsics</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6310</h3>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6311
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6312<div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6313
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6314<p>Variable argument support is defined in LLVM with
6315 the <a href="#i_va_arg"><tt>va_arg</tt></a> instruction and these three
6316 intrinsic functions. These functions are related to the similarly named
6317 macros defined in the <tt>&lt;stdarg.h&gt;</tt> header file.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6318
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6319<p>All of these functions operate on arguments that use a target-specific value
6320 type "<tt>va_list</tt>". The LLVM assembly language reference manual does
6321 not define what this type is, so all transformations should be prepared to
6322 handle these functions regardless of the type used.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6323
Chris Lattner374ab302006-05-15 17:26:46 +0000[diff] [blame]6324<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]6325 instruction and the variable argument handling intrinsic functions are
6326 used.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6327
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]6328<pre class="doc_code">
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]6329define i32 @test(i32 %X, ...) {
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6330 ; Initialize variable argument processing
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]6331 %ap = alloca i8*
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]6332 %ap2 = bitcast i8** %ap to i8*
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]6333 call void @llvm.va_start(i8* %ap2)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6334
6335 ; Read a single integer argument
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]6336 %tmp = va_arg i8** %ap, i32
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6337
6338 ; Demonstrate usage of llvm.va_copy and llvm.va_end
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]6339 %aq = alloca i8*
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]6340 %aq2 = bitcast i8** %aq to i8*
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]6341 call void @llvm.va_copy(i8* %aq2, i8* %ap2)
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]6342 call void @llvm.va_end(i8* %aq2)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6343
6344 ; Stop processing of arguments.
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]6345 call void @llvm.va_end(i8* %ap2)
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]6346 ret i32 %tmp
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6347}
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]6348
6349declare void @llvm.va_start(i8*)
6350declare void @llvm.va_copy(i8*, i8*)
6351declare void @llvm.va_end(i8*)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6352</pre>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6353
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6354<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6355<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6356 <a name="int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6357</h4>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6358
6359
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6360<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6361
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6362<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6363<pre>
6364 declare void %llvm.va_start(i8* &lt;arglist&gt;)
6365</pre>
6366
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6367<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6368<p>The '<tt>llvm.va_start</tt>' intrinsic initializes <tt>*&lt;arglist&gt;</tt>
6369 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]6370
6371<h5>Arguments:</h5>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]6372<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]6373
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6374<h5>Semantics:</h5>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]6375<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]6376 macro available in C. In a target-dependent way, it initializes
6377 the <tt>va_list</tt> element to which the argument points, so that the next
6378 call to <tt>va_arg</tt> will produce the first variable argument passed to
6379 the function. Unlike the C <tt>va_start</tt> macro, this intrinsic does not
6380 need to know the last argument of the function as the compiler can figure
6381 that out.</p>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]6382
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]6383</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6384
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6385<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6386<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6387 <a name="int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6388</h4>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6389
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6390<div>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]6391
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6392<h5>Syntax:</h5>
6393<pre>
6394 declare void @llvm.va_end(i8* &lt;arglist&gt;)
6395</pre>
6396
6397<h5>Overview:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]6398<p>The '<tt>llvm.va_end</tt>' intrinsic destroys <tt>*&lt;arglist&gt;</tt>,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6399 which has been initialized previously
6400 with <tt><a href="#int_va_start">llvm.va_start</a></tt>
6401 or <tt><a href="#i_va_copy">llvm.va_copy</a></tt>.</p>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]6402
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6403<h5>Arguments:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]6404<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]6405
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6406<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]6407<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]6408 macro available in C. In a target-dependent way, it destroys
6409 the <tt>va_list</tt> element to which the argument points. Calls
6410 to <a href="#int_va_start"><tt>llvm.va_start</tt></a>
6411 and <a href="#int_va_copy"> <tt>llvm.va_copy</tt></a> must be matched exactly
6412 with calls to <tt>llvm.va_end</tt>.</p>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]6413
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]6414</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6415
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6416<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6417<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6418 <a name="int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6419</h4>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6420
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6421<div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6422
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6423<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6424<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]6425 declare void @llvm.va_copy(i8* &lt;destarglist&gt;, i8* &lt;srcarglist&gt;)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6426</pre>
6427
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6428<h5>Overview:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]6429<p>The '<tt>llvm.va_copy</tt>' intrinsic copies the current argument position
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6430 from the source argument list to the destination argument list.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6431
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6432<h5>Arguments:</h5>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]6433<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]6434 The second argument is a pointer to a <tt>va_list</tt> element to copy
6435 from.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6436
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6437<h5>Semantics:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]6438<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]6439 macro available in C. In a target-dependent way, it copies the
6440 source <tt>va_list</tt> element into the destination <tt>va_list</tt>
6441 element. This intrinsic is necessary because
6442 the <tt><a href="#int_va_start"> llvm.va_start</a></tt> intrinsic may be
6443 arbitrarily complex and require, for example, memory allocation.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6444
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]6445</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6446
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6447</div>
6448
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6449<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6450<h3>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6451 <a name="int_gc">Accurate Garbage Collection Intrinsics</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6452</h3>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6453
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6454<div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6455
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6456<p>LLVM support for <a href="GarbageCollection.html">Accurate Garbage
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]6457Collection</a> (GC) requires the implementation and generation of these
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6458intrinsics. These intrinsics allow identification of <a href="#int_gcroot">GC
6459roots on the stack</a>, as well as garbage collector implementations that
6460require <a href="#int_gcread">read</a> and <a href="#int_gcwrite">write</a>
6461barriers. Front-ends for type-safe garbage collected languages should generate
6462these intrinsics to make use of the LLVM garbage collectors. For more details,
6463see <a href="GarbageCollection.html">Accurate Garbage Collection with
6464LLVM</a>.</p>
Christopher Lamb303dae92007-12-17 01:00:21 +0000[diff] [blame]6465
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6466<p>The garbage collection intrinsics only operate on objects in the generic
6467 address space (address space zero).</p>
Christopher Lamb303dae92007-12-17 01:00:21 +0000[diff] [blame]6468
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6469<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6470<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6471 <a name="int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6472</h4>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6473
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6474<div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6475
6476<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6477<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]6478 declare void @llvm.gcroot(i8** %ptrloc, i8* %metadata)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6479</pre>
6480
6481<h5>Overview:</h5>
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]6482<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]6483 the code generator, and allows some metadata to be associated with it.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6484
6485<h5>Arguments:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6486<p>The first argument specifies the address of a stack object that contains the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6487 root pointer. The second pointer (which must be either a constant or a
6488 global value address) contains the meta-data to be associated with the
6489 root.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6490
6491<h5>Semantics:</h5>
Chris Lattner05d67092008-04-24 05:59:56 +0000[diff] [blame]6492<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]6493 location. At compile-time, the code generator generates information to allow
6494 the runtime to find the pointer at GC safe points. The '<tt>llvm.gcroot</tt>'
6495 intrinsic may only be used in a function which <a href="#gc">specifies a GC
6496 algorithm</a>.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6497
6498</div>
6499
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6500<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6501<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6502 <a name="int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6503</h4>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6504
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6505<div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6506
6507<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6508<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]6509 declare i8* @llvm.gcread(i8* %ObjPtr, i8** %Ptr)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6510</pre>
6511
6512<h5>Overview:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6513<p>The '<tt>llvm.gcread</tt>' intrinsic identifies reads of references from heap
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6514 locations, allowing garbage collector implementations that require read
6515 barriers.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6516
6517<h5>Arguments:</h5>
Chris Lattner80626e92006-03-14 20:02:51 +0000[diff] [blame]6518<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]6519 allocated from the garbage collector. The first object is a pointer to the
6520 start of the referenced object, if needed by the language runtime (otherwise
6521 null).</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6522
6523<h5>Semantics:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6524<p>The '<tt>llvm.gcread</tt>' intrinsic has the same semantics as a load
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6525 instruction, but may be replaced with substantially more complex code by the
6526 garbage collector runtime, as needed. The '<tt>llvm.gcread</tt>' intrinsic
6527 may only be used in a function which <a href="#gc">specifies a GC
6528 algorithm</a>.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6529
6530</div>
6531
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6532<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6533<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6534 <a name="int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6535</h4>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6536
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6537<div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6538
6539<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6540<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]6541 declare void @llvm.gcwrite(i8* %P1, i8* %Obj, i8** %P2)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6542</pre>
6543
6544<h5>Overview:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6545<p>The '<tt>llvm.gcwrite</tt>' intrinsic identifies writes of references to heap
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6546 locations, allowing garbage collector implementations that require write
6547 barriers (such as generational or reference counting collectors).</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6548
6549<h5>Arguments:</h5>
Chris Lattner80626e92006-03-14 20:02:51 +0000[diff] [blame]6550<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]6551 object to store it to, and the third is the address of the field of Obj to
6552 store to. If the runtime does not require a pointer to the object, Obj may
6553 be null.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6554
6555<h5>Semantics:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6556<p>The '<tt>llvm.gcwrite</tt>' intrinsic has the same semantics as a store
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6557 instruction, but may be replaced with substantially more complex code by the
6558 garbage collector runtime, as needed. The '<tt>llvm.gcwrite</tt>' intrinsic
6559 may only be used in a function which <a href="#gc">specifies a GC
6560 algorithm</a>.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6561
6562</div>
6563
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6564</div>
6565
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6566<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6567<h3>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6568 <a name="int_codegen">Code Generator Intrinsics</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6569</h3>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6570
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6571<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6572
6573<p>These intrinsics are provided by LLVM to expose special features that may
6574 only be implemented with code generator support.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6575
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6576<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6577<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6578 <a name="int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6579</h4>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6580
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6581<div>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6582
6583<h5>Syntax:</h5>
6584<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]6585 declare i8 *@llvm.returnaddress(i32 &lt;level&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6586</pre>
6587
6588<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6589<p>The '<tt>llvm.returnaddress</tt>' intrinsic attempts to compute a
6590 target-specific value indicating the return address of the current function
6591 or one of its callers.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6592
6593<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6594<p>The argument to this intrinsic indicates which function to return the address
6595 for. Zero indicates the calling function, one indicates its caller, etc.
6596 The argument is <b>required</b> to be a constant integer value.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6597
6598<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6599<p>The '<tt>llvm.returnaddress</tt>' intrinsic either returns a pointer
6600 indicating the return address of the specified call frame, or zero if it
6601 cannot be identified. The value returned by this intrinsic is likely to be
6602 incorrect or 0 for arguments other than zero, so it should only be used for
6603 debugging purposes.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6604
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6605<p>Note that calling this intrinsic does not prevent function inlining or other
6606 aggressive transformations, so the value returned may not be that of the
6607 obvious source-language caller.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6608
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6609</div>
6610
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6611<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6612<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6613 <a name="int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6614</h4>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6615
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6616<div>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6617
6618<h5>Syntax:</h5>
6619<pre>
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]6620 declare i8* @llvm.frameaddress(i32 &lt;level&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6621</pre>
6622
6623<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6624<p>The '<tt>llvm.frameaddress</tt>' intrinsic attempts to return the
6625 target-specific frame pointer value for the specified stack frame.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6626
6627<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6628<p>The argument to this intrinsic indicates which function to return the frame
6629 pointer for. Zero indicates the calling function, one indicates its caller,
6630 etc. The argument is <b>required</b> to be a constant integer value.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6631
6632<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6633<p>The '<tt>llvm.frameaddress</tt>' intrinsic either returns a pointer
6634 indicating the frame address of the specified call frame, or zero if it
6635 cannot be identified. The value returned by this intrinsic is likely to be
6636 incorrect or 0 for arguments other than zero, so it should only be used for
6637 debugging purposes.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6638
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6639<p>Note that calling this intrinsic does not prevent function inlining or other
6640 aggressive transformations, so the value returned may not be that of the
6641 obvious source-language caller.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6642
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6643</div>
6644
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]6645<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6646<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6647 <a name="int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6648</h4>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]6649
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6650<div>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]6651
6652<h5>Syntax:</h5>
6653<pre>
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]6654 declare i8* @llvm.stacksave()
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]6655</pre>
6656
6657<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6658<p>The '<tt>llvm.stacksave</tt>' intrinsic is used to remember the current state
6659 of the function stack, for use
6660 with <a href="#int_stackrestore"> <tt>llvm.stackrestore</tt></a>. This is
6661 useful for implementing language features like scoped automatic variable
6662 sized arrays in C99.</p>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]6663
6664<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6665<p>This intrinsic returns a opaque pointer value that can be passed
6666 to <a href="#int_stackrestore"><tt>llvm.stackrestore</tt></a>. When
6667 an <tt>llvm.stackrestore</tt> intrinsic is executed with a value saved
6668 from <tt>llvm.stacksave</tt>, it effectively restores the state of the stack
6669 to the state it was in when the <tt>llvm.stacksave</tt> intrinsic executed.
6670 In practice, this pops any <a href="#i_alloca">alloca</a> blocks from the
6671 stack that were allocated after the <tt>llvm.stacksave</tt> was executed.</p>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]6672
6673</div>
6674
6675<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6676<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6677 <a name="int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6678</h4>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]6679
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6680<div>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]6681
6682<h5>Syntax:</h5>
6683<pre>
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]6684 declare void @llvm.stackrestore(i8* %ptr)
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]6685</pre>
6686
6687<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6688<p>The '<tt>llvm.stackrestore</tt>' intrinsic is used to restore the state of
6689 the function stack to the state it was in when the
6690 corresponding <a href="#int_stacksave"><tt>llvm.stacksave</tt></a> intrinsic
6691 executed. This is useful for implementing language features like scoped
6692 automatic variable sized arrays in C99.</p>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]6693
6694<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6695<p>See the description
6696 for <a href="#int_stacksave"><tt>llvm.stacksave</tt></a>.</p>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]6697
6698</div>
6699
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]6700<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6701<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6702 <a name="int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6703</h4>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]6704
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6705<div>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]6706
6707<h5>Syntax:</h5>
6708<pre>
Bruno Cardoso Lopes9a767332011-06-14 04:58:37 +0000[diff] [blame]6709 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]6710</pre>
6711
6712<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6713<p>The '<tt>llvm.prefetch</tt>' intrinsic is a hint to the code generator to
6714 insert a prefetch instruction if supported; otherwise, it is a noop.
6715 Prefetches have no effect on the behavior of the program but can change its
6716 performance characteristics.</p>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]6717
6718<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6719<p><tt>address</tt> is the address to be prefetched, <tt>rw</tt> is the
6720 specifier determining if the fetch should be for a read (0) or write (1),
6721 and <tt>locality</tt> is a temporal locality specifier ranging from (0) - no
Bruno Cardoso Lopes9a767332011-06-14 04:58:37 +0000[diff] [blame]6722 locality, to (3) - extremely local keep in cache. The <tt>cache type</tt>
6723 specifies whether the prefetch is performed on the data (1) or instruction (0)
6724 cache. The <tt>rw</tt>, <tt>locality</tt> and <tt>cache type</tt> arguments
6725 must be constant integers.</p>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]6726
6727<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6728<p>This intrinsic does not modify the behavior of the program. In particular,
6729 prefetches cannot trap and do not produce a value. On targets that support
6730 this intrinsic, the prefetch can provide hints to the processor cache for
6731 better performance.</p>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]6732
6733</div>
6734
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]6735<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6736<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6737 <a name="int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6738</h4>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]6739
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6740<div>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]6741
6742<h5>Syntax:</h5>
6743<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]6744 declare void @llvm.pcmarker(i32 &lt;id&gt;)
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]6745</pre>
6746
6747<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6748<p>The '<tt>llvm.pcmarker</tt>' intrinsic is a method to export a Program
6749 Counter (PC) in a region of code to simulators and other tools. The method
6750 is target specific, but it is expected that the marker will use exported
6751 symbols to transmit the PC of the marker. The marker makes no guarantees
6752 that it will remain with any specific instruction after optimizations. It is
6753 possible that the presence of a marker will inhibit optimizations. The
6754 intended use is to be inserted after optimizations to allow correlations of
6755 simulation runs.</p>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]6756
6757<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6758<p><tt>id</tt> is a numerical id identifying the marker.</p>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]6759
6760<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6761<p>This intrinsic does not modify the behavior of the program. Backends that do
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]6762 not support this intrinsic may ignore it.</p>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]6763
6764</div>
6765
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]6766<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6767<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6768 <a name="int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6769</h4>
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]6770
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6771<div>
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]6772
6773<h5>Syntax:</h5>
6774<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]6775 declare i64 @llvm.readcyclecounter()
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]6776</pre>
6777
6778<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6779<p>The '<tt>llvm.readcyclecounter</tt>' intrinsic provides access to the cycle
6780 counter register (or similar low latency, high accuracy clocks) on those
6781 targets that support it. On X86, it should map to RDTSC. On Alpha, it
6782 should map to RPCC. As the backing counters overflow quickly (on the order
6783 of 9 seconds on alpha), this should only be used for small timings.</p>
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]6784
6785<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6786<p>When directly supported, reading the cycle counter should not modify any
6787 memory. Implementations are allowed to either return a application specific
6788 value or a system wide value. On backends without support, this is lowered
6789 to a constant 0.</p>
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]6790
6791</div>
6792
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6793</div>
6794
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6795<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6796<h3>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6797 <a name="int_libc">Standard C Library Intrinsics</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6798</h3>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6799
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6800<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6801
6802<p>LLVM provides intrinsics for a few important standard C library functions.
6803 These intrinsics allow source-language front-ends to pass information about
6804 the alignment of the pointer arguments to the code generator, providing
6805 opportunity for more efficient code generation.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6806
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6807<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6808<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6809 <a name="int_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6810</h4>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6811
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6812<div>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6813
6814<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6815<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]6816 integer bit width and for different address spaces. Not all targets support
6817 all bit widths however.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6818
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6819<pre>
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]6820 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]6821 i32 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]6822 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]6823 i64 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6824</pre>
6825
6826<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6827<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
6828 source location to the destination location.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6829
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6830<p>Note that, unlike the standard libc function, the <tt>llvm.memcpy.*</tt>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6831 intrinsics do not return a value, takes extra alignment/isvolatile arguments
6832 and the pointers can be in specified address spaces.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6833
6834<h5>Arguments:</h5>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6835
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6836<p>The first argument is a pointer to the destination, the second is a pointer
6837 to the source. The third argument is an integer argument specifying the
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6838 number of bytes to copy, the fourth argument is the alignment of the
6839 source and destination locations, and the fifth is a boolean indicating a
6840 volatile access.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6841
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]6842<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]6843 then the caller guarantees that both the source and destination pointers are
6844 aligned to that boundary.</p>
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]6845
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]6846<p>If the <tt>isvolatile</tt> parameter is <tt>true</tt>, the
6847 <tt>llvm.memcpy</tt> call is a <a href="#volatile">volatile operation</a>.
6848 The detailed access behavior is not very cleanly specified and it is unwise
6849 to depend on it.</p>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6850
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6851<h5>Semantics:</h5>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6852
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6853<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
6854 source location to the destination location, which are not allowed to
6855 overlap. It copies "len" bytes of memory over. If the argument is known to
6856 be aligned to some boundary, this can be specified as the fourth argument,
6857 otherwise it should be set to 0 or 1.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6858
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6859</div>
6860
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6861<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6862<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6863 <a name="int_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6864</h4>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6865
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6866<div>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6867
6868<h5>Syntax:</h5>
Chris Lattner824b9582008-11-21 16:42:48 +0000[diff] [blame]6869<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]6870 width and for different address space. Not all targets support all bit
6871 widths however.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6872
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6873<pre>
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]6874 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]6875 i32 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]6876 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]6877 i64 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6878</pre>
6879
6880<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6881<p>The '<tt>llvm.memmove.*</tt>' intrinsics move a block of memory from the
6882 source location to the destination location. It is similar to the
6883 '<tt>llvm.memcpy</tt>' intrinsic but allows the two memory locations to
6884 overlap.</p>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6885
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6886<p>Note that, unlike the standard libc function, the <tt>llvm.memmove.*</tt>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6887 intrinsics do not return a value, takes extra alignment/isvolatile arguments
6888 and the pointers can be in specified address spaces.</p>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6889
6890<h5>Arguments:</h5>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6891
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6892<p>The first argument is a pointer to the destination, the second is a pointer
6893 to the source. The third argument is an integer argument specifying the
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6894 number of bytes to copy, the fourth argument is the alignment of the
6895 source and destination locations, and the fifth is a boolean indicating a
6896 volatile access.</p>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6897
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]6898<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]6899 then the caller guarantees that the source and destination pointers are
6900 aligned to that boundary.</p>
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]6901
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]6902<p>If the <tt>isvolatile</tt> parameter is <tt>true</tt>, the
6903 <tt>llvm.memmove</tt> call is a <a href="#volatile">volatile operation</a>.
6904 The detailed access behavior is not very cleanly specified and it is unwise
6905 to depend on it.</p>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6906
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6907<h5>Semantics:</h5>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6908
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6909<p>The '<tt>llvm.memmove.*</tt>' intrinsics copy a block of memory from the
6910 source location to the destination location, which may overlap. It copies
6911 "len" bytes of memory over. If the argument is known to be aligned to some
6912 boundary, this can be specified as the fourth argument, otherwise it should
6913 be set to 0 or 1.</p>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6914
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6915</div>
6916
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6917<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6918<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6919 <a name="int_memset">'<tt>llvm.memset.*</tt>' Intrinsics</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6920</h4>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6921
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6922<div>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6923
6924<h5>Syntax:</h5>
Chris Lattner824b9582008-11-21 16:42:48 +0000[diff] [blame]6925<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]6926 width and for different address spaces. However, not all targets support all
6927 bit widths.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6928
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6929<pre>
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]6930 declare void @llvm.memset.p0i8.i32(i8* &lt;dest&gt;, i8 &lt;val&gt;,
Chris Lattnerff35c3f2010-04-08 00:54:34 +0000[diff] [blame]6931 i32 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]6932 declare void @llvm.memset.p0i8.i64(i8* &lt;dest&gt;, i8 &lt;val&gt;,
Chris Lattnerff35c3f2010-04-08 00:54:34 +0000[diff] [blame]6933 i64 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6934</pre>
6935
6936<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6937<p>The '<tt>llvm.memset.*</tt>' intrinsics fill a block of memory with a
6938 particular byte value.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6939
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6940<p>Note that, unlike the standard libc function, the <tt>llvm.memset</tt>
John Criswellcdcbbfc2010-07-30 16:30:28 +0000[diff] [blame]6941 intrinsic does not return a value and takes extra alignment/volatile
6942 arguments. Also, the destination can be in an arbitrary address space.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6943
6944<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6945<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]6946 byte value with which to fill it, the third argument is an integer argument
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6947 specifying the number of bytes to fill, and the fourth argument is the known
John Criswellcdcbbfc2010-07-30 16:30:28 +0000[diff] [blame]6948 alignment of the destination location.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6949
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]6950<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]6951 then the caller guarantees that the destination pointer is aligned to that
6952 boundary.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6953
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]6954<p>If the <tt>isvolatile</tt> parameter is <tt>true</tt>, the
6955 <tt>llvm.memset</tt> call is a <a href="#volatile">volatile operation</a>.
6956 The detailed access behavior is not very cleanly specified and it is unwise
6957 to depend on it.</p>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6958
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6959<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6960<p>The '<tt>llvm.memset.*</tt>' intrinsics fill "len" bytes of memory starting
6961 at the destination location. If the argument is known to be aligned to some
6962 boundary, this can be specified as the fourth argument, otherwise it should
6963 be set to 0 or 1.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6964
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6965</div>
6966
Chris Lattner32006282004-06-11 02:28:03 +0000[diff] [blame]6967<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6968<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6969 <a name="int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6970</h4>
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]6971
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6972<div>
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]6973
6974<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6975<p>This is an overloaded intrinsic. You can use <tt>llvm.sqrt</tt> on any
6976 floating point or vector of floating point type. Not all targets support all
6977 types however.</p>
6978
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]6979<pre>
Dale Johannesen408f9c12007-10-02 17:47:38 +0000[diff] [blame]6980 declare float @llvm.sqrt.f32(float %Val)
6981 declare double @llvm.sqrt.f64(double %Val)
6982 declare x86_fp80 @llvm.sqrt.f80(x86_fp80 %Val)
6983 declare fp128 @llvm.sqrt.f128(fp128 %Val)
6984 declare ppc_fp128 @llvm.sqrt.ppcf128(ppc_fp128 %Val)
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]6985</pre>
6986
6987<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6988<p>The '<tt>llvm.sqrt</tt>' intrinsics return the sqrt of the specified operand,
6989 returning the same value as the libm '<tt>sqrt</tt>' functions would.
6990 Unlike <tt>sqrt</tt> in libm, however, <tt>llvm.sqrt</tt> has undefined
6991 behavior for negative numbers other than -0.0 (which allows for better
6992 optimization, because there is no need to worry about errno being
6993 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]6994
6995<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6996<p>The argument and return value are floating point numbers of the same
6997 type.</p>
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]6998
6999<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7000<p>This function returns the sqrt of the specified operand if it is a
7001 nonnegative floating point number.</p>
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]7002
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]7003</div>
7004
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]7005<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7006<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]7007 <a name="int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7008</h4>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]7009
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7010<div>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]7011
7012<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7013<p>This is an overloaded intrinsic. You can use <tt>llvm.powi</tt> on any
7014 floating point or vector of floating point type. Not all targets support all
7015 types however.</p>
7016
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]7017<pre>
Dale Johannesen408f9c12007-10-02 17:47:38 +0000[diff] [blame]7018 declare float @llvm.powi.f32(float %Val, i32 %power)
7019 declare double @llvm.powi.f64(double %Val, i32 %power)
7020 declare x86_fp80 @llvm.powi.f80(x86_fp80 %Val, i32 %power)
7021 declare fp128 @llvm.powi.f128(fp128 %Val, i32 %power)
7022 declare ppc_fp128 @llvm.powi.ppcf128(ppc_fp128 %Val, i32 %power)
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]7023</pre>
7024
7025<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7026<p>The '<tt>llvm.powi.*</tt>' intrinsics return the first operand raised to the
7027 specified (positive or negative) power. The order of evaluation of
7028 multiplications is not defined. When a vector of floating point type is
7029 used, the second argument remains a scalar integer value.</p>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]7030
7031<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7032<p>The second argument is an integer power, and the first is a value to raise to
7033 that power.</p>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]7034
7035<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7036<p>This function returns the first value raised to the second power with an
7037 unspecified sequence of rounding operations.</p>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]7038
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]7039</div>
7040
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7041<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7042<h4>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7043 <a name="int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7044</h4>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7045
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7046<div>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7047
7048<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7049<p>This is an overloaded intrinsic. You can use <tt>llvm.sin</tt> on any
7050 floating point or vector of floating point type. Not all targets support all
7051 types however.</p>
7052
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7053<pre>
7054 declare float @llvm.sin.f32(float %Val)
7055 declare double @llvm.sin.f64(double %Val)
7056 declare x86_fp80 @llvm.sin.f80(x86_fp80 %Val)
7057 declare fp128 @llvm.sin.f128(fp128 %Val)
7058 declare ppc_fp128 @llvm.sin.ppcf128(ppc_fp128 %Val)
7059</pre>
7060
7061<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7062<p>The '<tt>llvm.sin.*</tt>' intrinsics return the sine of the operand.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7063
7064<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7065<p>The argument and return value are floating point numbers of the same
7066 type.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7067
7068<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7069<p>This function returns the sine of the specified operand, returning the same
7070 values as the libm <tt>sin</tt> functions would, and handles error conditions
7071 in the same way.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7072
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7073</div>
7074
7075<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7076<h4>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7077 <a name="int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7078</h4>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7079
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7080<div>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7081
7082<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7083<p>This is an overloaded intrinsic. You can use <tt>llvm.cos</tt> on any
7084 floating point or vector of floating point type. Not all targets support all
7085 types however.</p>
7086
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7087<pre>
7088 declare float @llvm.cos.f32(float %Val)
7089 declare double @llvm.cos.f64(double %Val)
7090 declare x86_fp80 @llvm.cos.f80(x86_fp80 %Val)
7091 declare fp128 @llvm.cos.f128(fp128 %Val)
7092 declare ppc_fp128 @llvm.cos.ppcf128(ppc_fp128 %Val)
7093</pre>
7094
7095<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7096<p>The '<tt>llvm.cos.*</tt>' intrinsics return the cosine of the operand.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7097
7098<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7099<p>The argument and return value are floating point numbers of the same
7100 type.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7101
7102<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7103<p>This function returns the cosine of the specified operand, returning the same
7104 values as the libm <tt>cos</tt> functions would, and handles error conditions
7105 in the same way.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7106
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7107</div>
7108
7109<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7110<h4>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7111 <a name="int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7112</h4>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7113
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7114<div>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7115
7116<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7117<p>This is an overloaded intrinsic. You can use <tt>llvm.pow</tt> on any
7118 floating point or vector of floating point type. Not all targets support all
7119 types however.</p>
7120
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7121<pre>
7122 declare float @llvm.pow.f32(float %Val, float %Power)
7123 declare double @llvm.pow.f64(double %Val, double %Power)
7124 declare x86_fp80 @llvm.pow.f80(x86_fp80 %Val, x86_fp80 %Power)
7125 declare fp128 @llvm.pow.f128(fp128 %Val, fp128 %Power)
7126 declare ppc_fp128 @llvm.pow.ppcf128(ppc_fp128 %Val, ppc_fp128 Power)
7127</pre>
7128
7129<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7130<p>The '<tt>llvm.pow.*</tt>' intrinsics return the first operand raised to the
7131 specified (positive or negative) power.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7132
7133<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7134<p>The second argument is a floating point power, and the first is a value to
7135 raise to that power.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7136
7137<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7138<p>This function returns the first value raised to the second power, returning
7139 the same values as the libm <tt>pow</tt> functions would, and handles error
7140 conditions in the same way.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7141
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7142</div>
7143
Dan Gohman4e9011c2011-05-23 21:13:03 +0000[diff] [blame]7144<!-- _______________________________________________________________________ -->
7145<h4>
7146 <a name="int_exp">'<tt>llvm.exp.*</tt>' Intrinsic</a>
7147</h4>
7148
7149<div>
7150
7151<h5>Syntax:</h5>
7152<p>This is an overloaded intrinsic. You can use <tt>llvm.exp</tt> on any
7153 floating point or vector of floating point type. Not all targets support all
7154 types however.</p>
7155
7156<pre>
7157 declare float @llvm.exp.f32(float %Val)
7158 declare double @llvm.exp.f64(double %Val)
7159 declare x86_fp80 @llvm.exp.f80(x86_fp80 %Val)
7160 declare fp128 @llvm.exp.f128(fp128 %Val)
7161 declare ppc_fp128 @llvm.exp.ppcf128(ppc_fp128 %Val)
7162</pre>
7163
7164<h5>Overview:</h5>
7165<p>The '<tt>llvm.exp.*</tt>' intrinsics perform the exp function.</p>
7166
7167<h5>Arguments:</h5>
7168<p>The argument and return value are floating point numbers of the same
7169 type.</p>
7170
7171<h5>Semantics:</h5>
7172<p>This function returns the same values as the libm <tt>exp</tt> functions
7173 would, and handles error conditions in the same way.</p>
7174
7175</div>
7176
7177<!-- _______________________________________________________________________ -->
7178<h4>
7179 <a name="int_log">'<tt>llvm.log.*</tt>' Intrinsic</a>
7180</h4>
7181
7182<div>
7183
7184<h5>Syntax:</h5>
7185<p>This is an overloaded intrinsic. You can use <tt>llvm.log</tt> on any
7186 floating point or vector of floating point type. Not all targets support all
7187 types however.</p>
7188
7189<pre>
7190 declare float @llvm.log.f32(float %Val)
7191 declare double @llvm.log.f64(double %Val)
7192 declare x86_fp80 @llvm.log.f80(x86_fp80 %Val)
7193 declare fp128 @llvm.log.f128(fp128 %Val)
7194 declare ppc_fp128 @llvm.log.ppcf128(ppc_fp128 %Val)
7195</pre>
7196
7197<h5>Overview:</h5>
7198<p>The '<tt>llvm.log.*</tt>' intrinsics perform the log function.</p>
7199
7200<h5>Arguments:</h5>
7201<p>The argument and return value are floating point numbers of the same
7202 type.</p>
7203
7204<h5>Semantics:</h5>
7205<p>This function returns the same values as the libm <tt>log</tt> functions
7206 would, and handles error conditions in the same way.</p>
7207
Nick Lewycky1c929be2011-10-31 01:32:21 +0000[diff] [blame]7208</div>
7209
7210<!-- _______________________________________________________________________ -->
Cameron Zwarich33390842011-07-08 21:39:21 +0000[diff] [blame]7211<h4>
7212 <a name="int_fma">'<tt>llvm.fma.*</tt>' Intrinsic</a>
7213</h4>
7214
7215<div>
7216
7217<h5>Syntax:</h5>
7218<p>This is an overloaded intrinsic. You can use <tt>llvm.fma</tt> on any
7219 floating point or vector of floating point type. Not all targets support all
7220 types however.</p>
7221
7222<pre>
7223 declare float @llvm.fma.f32(float %a, float %b, float %c)
7224 declare double @llvm.fma.f64(double %a, double %b, double %c)
7225 declare x86_fp80 @llvm.fma.f80(x86_fp80 %a, x86_fp80 %b, x86_fp80 %c)
7226 declare fp128 @llvm.fma.f128(fp128 %a, fp128 %b, fp128 %c)
7227 declare ppc_fp128 @llvm.fma.ppcf128(ppc_fp128 %a, ppc_fp128 %b, ppc_fp128 %c)
7228</pre>
7229
7230<h5>Overview:</h5>
Cameron Zwarichabc43e62011-07-08 22:13:55 +0000[diff] [blame]7231<p>The '<tt>llvm.fma.*</tt>' intrinsics perform the fused multiply-add
Cameron Zwarich33390842011-07-08 21:39:21 +0000[diff] [blame]7232 operation.</p>
7233
7234<h5>Arguments:</h5>
7235<p>The argument and return value are floating point numbers of the same
7236 type.</p>
7237
7238<h5>Semantics:</h5>
7239<p>This function returns the same values as the libm <tt>fma</tt> functions
7240 would.</p>
7241
Dan Gohman4e9011c2011-05-23 21:13:03 +0000[diff] [blame]7242</div>
7243
NAKAMURA Takumi4b2e07a2011-10-31 13:04:26 +0000[diff] [blame]7244</div>
7245
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7246<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7247<h3>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]7248 <a name="int_manip">Bit Manipulation Intrinsics</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7249</h3>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7250
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7251<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7252
7253<p>LLVM provides intrinsics for a few important bit manipulation operations.
7254 These allow efficient code generation for some algorithms.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7255
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7256<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7257<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]7258 <a name="int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7259</h4>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]7260
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7261<div>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]7262
7263<h5>Syntax:</h5>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]7264<p>This is an overloaded intrinsic function. You can use bswap on any integer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7265 type that is an even number of bytes (i.e. BitWidth % 16 == 0).</p>
7266
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]7267<pre>
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]7268 declare i16 @llvm.bswap.i16(i16 &lt;id&gt;)
7269 declare i32 @llvm.bswap.i32(i32 &lt;id&gt;)
7270 declare i64 @llvm.bswap.i64(i64 &lt;id&gt;)
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]7271</pre>
7272
7273<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7274<p>The '<tt>llvm.bswap</tt>' family of intrinsics is used to byte swap integer
7275 values with an even number of bytes (positive multiple of 16 bits). These
7276 are useful for performing operations on data that is not in the target's
7277 native byte order.</p>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]7278
7279<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7280<p>The <tt>llvm.bswap.i16</tt> intrinsic returns an i16 value that has the high
7281 and low byte of the input i16 swapped. Similarly,
7282 the <tt>llvm.bswap.i32</tt> intrinsic returns an i32 value that has the four
7283 bytes of the input i32 swapped, so that if the input bytes are numbered 0, 1,
7284 2, 3 then the returned i32 will have its bytes in 3, 2, 1, 0 order.
7285 The <tt>llvm.bswap.i48</tt>, <tt>llvm.bswap.i64</tt> and other intrinsics
7286 extend this concept to additional even-byte lengths (6 bytes, 8 bytes and
7287 more, respectively).</p>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]7288
7289</div>
7290
7291<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7292<h4>
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]7293 <a name="int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7294</h4>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7295
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7296<div>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7297
7298<h5>Syntax:</h5>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]7299<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]7300 width, or on any vector with integer elements. Not all targets support all
7301 bit widths or vector types, however.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7302
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7303<pre>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7304 declare i8 @llvm.ctpop.i8(i8 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]7305 declare i16 @llvm.ctpop.i16(i16 &lt;src&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]7306 declare i32 @llvm.ctpop.i32(i32 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]7307 declare i64 @llvm.ctpop.i64(i64 &lt;src&gt;)
7308 declare i256 @llvm.ctpop.i256(i256 &lt;src&gt;)
Owen Andersonf1ac4652011-07-01 21:52:38 +0000[diff] [blame]7309 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]7310</pre>
7311
7312<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7313<p>The '<tt>llvm.ctpop</tt>' family of intrinsics counts the number of bits set
7314 in a value.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7315
7316<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7317<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]7318 integer type, or a vector with integer elements.
7319 The return type must match the argument type.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7320
7321<h5>Semantics:</h5>
Owen Andersonf1ac4652011-07-01 21:52:38 +0000[diff] [blame]7322<p>The '<tt>llvm.ctpop</tt>' intrinsic counts the 1's in a variable, or within each
7323 element of a vector.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7324
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7325</div>
7326
7327<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7328<h4>
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]7329 <a name="int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7330</h4>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7331
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7332<div>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7333
7334<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7335<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]7336 integer bit width, or any vector whose elements are integers. Not all
7337 targets support all bit widths or vector types, however.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7338
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7339<pre>
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]7340 declare i8 @llvm.ctlz.i8 (i8 &lt;src&gt;)
7341 declare i16 @llvm.ctlz.i16(i16 &lt;src&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]7342 declare i32 @llvm.ctlz.i32(i32 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]7343 declare i64 @llvm.ctlz.i64(i64 &lt;src&gt;)
7344 declare i256 @llvm.ctlz.i256(i256 &lt;src&gt;)
Owen Andersonf1ac4652011-07-01 21:52:38 +0000[diff] [blame]7345 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]7346</pre>
7347
7348<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7349<p>The '<tt>llvm.ctlz</tt>' family of intrinsic functions counts the number of
7350 leading zeros in a variable.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7351
7352<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7353<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]7354 integer type, or any vector type with integer element type.
7355 The return type must match the argument type.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7356
7357<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7358<p>The '<tt>llvm.ctlz</tt>' intrinsic counts the leading (most significant)
Owen Andersonf1ac4652011-07-01 21:52:38 +0000[diff] [blame]7359 zeros in a variable, or within each element of the vector if the operation
7360 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]7361 the type of src. For example, <tt>llvm.ctlz(i32 2) = 30</tt>.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7362
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7363</div>
Chris Lattner32006282004-06-11 02:28:03 +0000[diff] [blame]7364
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]7365<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7366<h4>
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]7367 <a name="int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7368</h4>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]7369
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7370<div>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]7371
7372<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7373<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]7374 integer bit width, or any vector of integer elements. Not all targets
7375 support all bit widths or vector types, however.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7376
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]7377<pre>
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]7378 declare i8 @llvm.cttz.i8 (i8 &lt;src&gt;)
7379 declare i16 @llvm.cttz.i16(i16 &lt;src&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]7380 declare i32 @llvm.cttz.i32(i32 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]7381 declare i64 @llvm.cttz.i64(i64 &lt;src&gt;)
7382 declare i256 @llvm.cttz.i256(i256 &lt;src&gt;)
Owen Andersonf1ac4652011-07-01 21:52:38 +0000[diff] [blame]7383 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]7384</pre>
7385
7386<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7387<p>The '<tt>llvm.cttz</tt>' family of intrinsic functions counts the number of
7388 trailing zeros.</p>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]7389
7390<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7391<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]7392 integer type, or a vectory with integer element type.. The return type
7393 must match the argument type.</p>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]7394
7395<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7396<p>The '<tt>llvm.cttz</tt>' intrinsic counts the trailing (least significant)
Owen Andersonf1ac4652011-07-01 21:52:38 +0000[diff] [blame]7397 zeros in a variable, or within each element of a vector.
7398 If the src == 0 then the result is the size in bits of
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7399 the type of src. For example, <tt>llvm.cttz(2) = 1</tt>.</p>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]7400
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]7401</div>
7402
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7403</div>
7404
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]7405<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7406<h3>
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]7407 <a name="int_overflow">Arithmetic with Overflow Intrinsics</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7408</h3>
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]7409
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7410<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7411
7412<p>LLVM provides intrinsics for some arithmetic with overflow operations.</p>
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]7413
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7414<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7415<h4>
7416 <a name="int_sadd_overflow">
7417 '<tt>llvm.sadd.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.sadd.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.sadd.with.overflow.i16(i16 %a, i16 %b)
7429 declare {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
7430 declare {i64, i1} @llvm.sadd.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.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7435 a signed addition of the two arguments, and indicate whether an overflow
7436 occurred during the signed summation.</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 signed addition.</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.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7447 a signed addition of the two variables. They return a structure &mdash; the
7448 first element of which is the signed summation, and the second element of
7449 which is a bit specifying if the signed summation 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.sadd.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_uadd_overflow">
7465 '<tt>llvm.uadd.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.uadd.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.uadd.with.overflow.i16(i16 %a, i16 %b)
7477 declare {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
7478 declare {i64, i1} @llvm.uadd.with.overflow.i64(i64 %a, i64 %b)
7479</pre>
7480
7481<h5>Overview:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7482<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7483 an unsigned addition of the two arguments, and indicate whether a carry
7484 occurred during the unsigned summation.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7485
7486<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7487<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]7488 be of integer types of any bit width, but they must have the same bit
7489 width. The second element of the result structure must be of
7490 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
7491 undergo unsigned addition.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7492
7493<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7494<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7495 an unsigned addition of the two arguments. They return a structure &mdash;
7496 the first element of which is the sum, and the second element of which is a
7497 bit specifying if the unsigned summation resulted in a carry.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7498
7499<h5>Examples:</h5>
7500<pre>
7501 %res = call {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
7502 %sum = extractvalue {i32, i1} %res, 0
7503 %obit = extractvalue {i32, i1} %res, 1
7504 br i1 %obit, label %carry, label %normal
7505</pre>
7506
7507</div>
7508
7509<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7510<h4>
7511 <a name="int_ssub_overflow">
7512 '<tt>llvm.ssub.with.overflow.*</tt>' Intrinsics
7513 </a>
7514</h4>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7515
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7516<div>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7517
7518<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7519<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]7520 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7521
7522<pre>
7523 declare {i16, i1} @llvm.ssub.with.overflow.i16(i16 %a, i16 %b)
7524 declare {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
7525 declare {i64, i1} @llvm.ssub.with.overflow.i64(i64 %a, i64 %b)
7526</pre>
7527
7528<h5>Overview:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7529<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7530 a signed subtraction of the two arguments, and indicate whether an overflow
7531 occurred during the signed subtraction.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7532
7533<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7534<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]7535 be of integer types of any bit width, but they must have the same bit
7536 width. The second element of the result structure must be of
7537 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
7538 undergo signed subtraction.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7539
7540<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7541<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7542 a signed subtraction of the two arguments. They return a structure &mdash;
7543 the first element of which is the subtraction, and the second element of
7544 which is a bit specifying if the signed subtraction resulted in an
7545 overflow.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7546
7547<h5>Examples:</h5>
7548<pre>
7549 %res = call {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
7550 %sum = extractvalue {i32, i1} %res, 0
7551 %obit = extractvalue {i32, i1} %res, 1
7552 br i1 %obit, label %overflow, label %normal
7553</pre>
7554
7555</div>
7556
7557<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7558<h4>
7559 <a name="int_usub_overflow">
7560 '<tt>llvm.usub.with.overflow.*</tt>' Intrinsics
7561 </a>
7562</h4>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7563
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7564<div>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7565
7566<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7567<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]7568 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7569
7570<pre>
7571 declare {i16, i1} @llvm.usub.with.overflow.i16(i16 %a, i16 %b)
7572 declare {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
7573 declare {i64, i1} @llvm.usub.with.overflow.i64(i64 %a, i64 %b)
7574</pre>
7575
7576<h5>Overview:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7577<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7578 an unsigned subtraction of the two arguments, and indicate whether an
7579 overflow occurred during the unsigned subtraction.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7580
7581<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7582<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]7583 be of integer types of any bit width, but they must have the same bit
7584 width. The second element of the result structure must be of
7585 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
7586 undergo unsigned subtraction.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7587
7588<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7589<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7590 an unsigned subtraction of the two arguments. They return a structure &mdash;
7591 the first element of which is the subtraction, and the second element of
7592 which is a bit specifying if the unsigned subtraction resulted in an
7593 overflow.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7594
7595<h5>Examples:</h5>
7596<pre>
7597 %res = call {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
7598 %sum = extractvalue {i32, i1} %res, 0
7599 %obit = extractvalue {i32, i1} %res, 1
7600 br i1 %obit, label %overflow, label %normal
7601</pre>
7602
7603</div>
7604
7605<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7606<h4>
7607 <a name="int_smul_overflow">
7608 '<tt>llvm.smul.with.overflow.*</tt>' Intrinsics
7609 </a>
7610</h4>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7611
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7612<div>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7613
7614<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7615<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]7616 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7617
7618<pre>
7619 declare {i16, i1} @llvm.smul.with.overflow.i16(i16 %a, i16 %b)
7620 declare {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
7621 declare {i64, i1} @llvm.smul.with.overflow.i64(i64 %a, i64 %b)
7622</pre>
7623
7624<h5>Overview:</h5>
7625
7626<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7627 a signed multiplication of the two arguments, and indicate whether an
7628 overflow occurred during the signed multiplication.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7629
7630<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7631<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]7632 be of integer types of any bit width, but they must have the same bit
7633 width. The second element of the result structure must be of
7634 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
7635 undergo signed multiplication.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7636
7637<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7638<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7639 a signed multiplication of the two arguments. They return a structure &mdash;
7640 the first element of which is the multiplication, and the second element of
7641 which is a bit specifying if the signed multiplication resulted in an
7642 overflow.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7643
7644<h5>Examples:</h5>
7645<pre>
7646 %res = call {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
7647 %sum = extractvalue {i32, i1} %res, 0
7648 %obit = extractvalue {i32, i1} %res, 1
7649 br i1 %obit, label %overflow, label %normal
7650</pre>
7651
Reid Spencerf86037f2007-04-11 23:23:49 +0000[diff] [blame]7652</div>
7653
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]7654<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7655<h4>
7656 <a name="int_umul_overflow">
7657 '<tt>llvm.umul.with.overflow.*</tt>' Intrinsics
7658 </a>
7659</h4>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]7660
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7661<div>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]7662
7663<h5>Syntax:</h5>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]7664<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]7665 on any integer bit width.</p>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]7666
7667<pre>
7668 declare {i16, i1} @llvm.umul.with.overflow.i16(i16 %a, i16 %b)
7669 declare {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
7670 declare {i64, i1} @llvm.umul.with.overflow.i64(i64 %a, i64 %b)
7671</pre>
7672
7673<h5>Overview:</h5>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]7674<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7675 a unsigned multiplication of the two arguments, and indicate whether an
7676 overflow occurred during the unsigned multiplication.</p>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]7677
7678<h5>Arguments:</h5>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]7679<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]7680 be of integer types of any bit width, but they must have the same bit
7681 width. The second element of the result structure must be of
7682 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
7683 undergo unsigned multiplication.</p>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]7684
7685<h5>Semantics:</h5>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]7686<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7687 an unsigned multiplication of the two arguments. They return a structure
7688 &mdash; the first element of which is the multiplication, and the second
7689 element of which is a bit specifying if the unsigned multiplication resulted
7690 in an overflow.</p>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]7691
7692<h5>Examples:</h5>
7693<pre>
7694 %res = call {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
7695 %sum = extractvalue {i32, i1} %res, 0
7696 %obit = extractvalue {i32, i1} %res, 1
7697 br i1 %obit, label %overflow, label %normal
7698</pre>
7699
7700</div>
7701
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7702</div>
7703
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]7704<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7705<h3>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]7706 <a name="int_fp16">Half Precision Floating Point Intrinsics</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7707</h3>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]7708
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7709<div>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]7710
Chris Lattner0cec9c82010-03-15 04:12:21 +0000[diff] [blame]7711<p>Half precision floating point is a storage-only format. This means that it is
7712 a dense encoding (in memory) but does not support computation in the
7713 format.</p>
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]7714
Chris Lattner0cec9c82010-03-15 04:12:21 +0000[diff] [blame]7715<p>This means that code must first load the half-precision floating point
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]7716 value as an i16, then convert it to float with <a
7717 href="#int_convert_from_fp16"><tt>llvm.convert.from.fp16</tt></a>.
7718 Computation can then be performed on the float value (including extending to
Chris Lattner0cec9c82010-03-15 04:12:21 +0000[diff] [blame]7719 double etc). To store the value back to memory, it is first converted to
7720 float if needed, then converted to i16 with
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]7721 <a href="#int_convert_to_fp16"><tt>llvm.convert.to.fp16</tt></a>, then
7722 storing as an i16 value.</p>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]7723
7724<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7725<h4>
7726 <a name="int_convert_to_fp16">
7727 '<tt>llvm.convert.to.fp16</tt>' Intrinsic
7728 </a>
7729</h4>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]7730
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7731<div>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]7732
7733<h5>Syntax:</h5>
7734<pre>
7735 declare i16 @llvm.convert.to.fp16(f32 %a)
7736</pre>
7737
7738<h5>Overview:</h5>
7739<p>The '<tt>llvm.convert.to.fp16</tt>' intrinsic function performs
7740 a conversion from single precision floating point format to half precision
7741 floating point format.</p>
7742
7743<h5>Arguments:</h5>
7744<p>The intrinsic function contains single argument - the value to be
7745 converted.</p>
7746
7747<h5>Semantics:</h5>
7748<p>The '<tt>llvm.convert.to.fp16</tt>' intrinsic function performs
7749 a conversion from single precision floating point format to half precision
Chris Lattner0cec9c82010-03-15 04:12:21 +0000[diff] [blame]7750 floating point format. The return value is an <tt>i16</tt> which
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]7751 contains the converted number.</p>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]7752
7753<h5>Examples:</h5>
7754<pre>
7755 %res = call i16 @llvm.convert.to.fp16(f32 %a)
7756 store i16 %res, i16* @x, align 2
7757</pre>
7758
7759</div>
7760
7761<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7762<h4>
7763 <a name="int_convert_from_fp16">
7764 '<tt>llvm.convert.from.fp16</tt>' Intrinsic
7765 </a>
7766</h4>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]7767
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7768<div>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]7769
7770<h5>Syntax:</h5>
7771<pre>
7772 declare f32 @llvm.convert.from.fp16(i16 %a)
7773</pre>
7774
7775<h5>Overview:</h5>
7776<p>The '<tt>llvm.convert.from.fp16</tt>' intrinsic function performs
7777 a conversion from half precision floating point format to single precision
7778 floating point format.</p>
7779
7780<h5>Arguments:</h5>
7781<p>The intrinsic function contains single argument - the value to be
7782 converted.</p>
7783
7784<h5>Semantics:</h5>
7785<p>The '<tt>llvm.convert.from.fp16</tt>' intrinsic function performs a
Chris Lattner0cec9c82010-03-15 04:12:21 +0000[diff] [blame]7786 conversion from half single precision floating point format to single
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]7787 precision floating point format. The input half-float value is represented by
7788 an <tt>i16</tt> value.</p>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]7789
7790<h5>Examples:</h5>
7791<pre>
7792 %a = load i16* @x, align 2
7793 %res = call f32 @llvm.convert.from.fp16(i16 %a)
7794</pre>
7795
7796</div>
7797
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7798</div>
7799
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]7800<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7801<h3>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]7802 <a name="int_debugger">Debugger Intrinsics</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7803</h3>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]7804
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7805<div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]7806
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7807<p>The LLVM debugger intrinsics (which all start with <tt>llvm.dbg.</tt>
7808 prefix), are described in
7809 the <a href="SourceLevelDebugging.html#format_common_intrinsics">LLVM Source
7810 Level Debugging</a> document.</p>
7811
7812</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]7813
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]7814<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7815<h3>
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]7816 <a name="int_eh">Exception Handling Intrinsics</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7817</h3>
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]7818
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7819<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7820
7821<p>The LLVM exception handling intrinsics (which all start with
7822 <tt>llvm.eh.</tt> prefix), are described in
7823 the <a href="ExceptionHandling.html#format_common_intrinsics">LLVM Exception
7824 Handling</a> document.</p>
7825
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]7826</div>
7827
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]7828<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7829<h3>
Duncan Sands4a544a72011-09-06 13:37:06 +0000[diff] [blame]7830 <a name="int_trampoline">Trampoline Intrinsics</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7831</h3>
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]7832
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7833<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7834
Duncan Sands4a544a72011-09-06 13:37:06 +0000[diff] [blame]7835<p>These intrinsics make it possible to excise one parameter, marked with
Dan Gohmanff235352010-07-02 23:18:08 +0000[diff] [blame]7836 the <a href="#nest"><tt>nest</tt></a> attribute, from a function.
7837 The result is a callable
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7838 function pointer lacking the nest parameter - the caller does not need to
7839 provide a value for it. Instead, the value to use is stored in advance in a
7840 "trampoline", a block of memory usually allocated on the stack, which also
7841 contains code to splice the nest value into the argument list. This is used
7842 to implement the GCC nested function address extension.</p>
7843
7844<p>For example, if the function is
7845 <tt>i32 f(i8* nest %c, i32 %x, i32 %y)</tt> then the resulting function
7846 pointer has signature <tt>i32 (i32, i32)*</tt>. It can be created as
7847 follows:</p>
7848
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]7849<pre class="doc_code">
Duncan Sandsf7331b32007-09-11 14:10:23 +0000[diff] [blame]7850 %tramp = alloca [10 x i8], align 4 ; size and alignment only correct for X86
7851 %tramp1 = getelementptr [10 x i8]* %tramp, i32 0, i32 0
Duncan Sands4a544a72011-09-06 13:37:06 +0000[diff] [blame]7852 call i8* @llvm.init.trampoline(i8* %tramp1, i8* bitcast (i32 (i8*, i32, i32)* @f to i8*), i8* %nval)
7853 %p = call i8* @llvm.adjust.trampoline(i8* %tramp1)
Duncan Sandsf7331b32007-09-11 14:10:23 +0000[diff] [blame]7854 %fp = bitcast i8* %p to i32 (i32, i32)*
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]7855</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7856
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7857<p>The call <tt>%val = call i32 %fp(i32 %x, i32 %y)</tt> is then equivalent
7858 to <tt>%val = call i32 %f(i8* %nval, i32 %x, i32 %y)</tt>.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7859
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]7860<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7861<h4>
7862 <a name="int_it">
7863 '<tt>llvm.init.trampoline</tt>' Intrinsic
7864 </a>
7865</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7866
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7867<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7868
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]7869<h5>Syntax:</h5>
7870<pre>
Duncan Sands4a544a72011-09-06 13:37:06 +0000[diff] [blame]7871 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]7872</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7873
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]7874<h5>Overview:</h5>
Duncan Sands4a544a72011-09-06 13:37:06 +0000[diff] [blame]7875<p>This fills the memory pointed to by <tt>tramp</tt> with executable code,
7876 turning it into a trampoline.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7877
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]7878<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7879<p>The <tt>llvm.init.trampoline</tt> intrinsic takes three arguments, all
7880 pointers. The <tt>tramp</tt> argument must point to a sufficiently large and
7881 sufficiently aligned block of memory; this memory is written to by the
7882 intrinsic. Note that the size and the alignment are target-specific - LLVM
7883 currently provides no portable way of determining them, so a front-end that
7884 generates this intrinsic needs to have some target-specific knowledge.
7885 The <tt>func</tt> argument must hold a function bitcast to
7886 an <tt>i8*</tt>.</p>
7887
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]7888<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7889<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]7890 dependent code, turning it into a function. Then <tt>tramp</tt> needs to be
7891 passed to <a href="#int_at">llvm.adjust.trampoline</a> to get a pointer
7892 which can be <a href="#int_trampoline">bitcast (to a new function) and
7893 called</a>. The new function's signature is the same as that of
7894 <tt>func</tt> with any arguments marked with the <tt>nest</tt> attribute
7895 removed. At most one such <tt>nest</tt> argument is allowed, and it must be of
7896 pointer type. Calling the new function is equivalent to calling <tt>func</tt>
7897 with the same argument list, but with <tt>nval</tt> used for the missing
7898 <tt>nest</tt> argument. If, after calling <tt>llvm.init.trampoline</tt>, the
7899 memory pointed to by <tt>tramp</tt> is modified, then the effect of any later call
7900 to the returned function pointer is undefined.</p>
7901</div>
7902
7903<!-- _______________________________________________________________________ -->
7904<h4>
7905 <a name="int_at">
7906 '<tt>llvm.adjust.trampoline</tt>' Intrinsic
7907 </a>
7908</h4>
7909
7910<div>
7911
7912<h5>Syntax:</h5>
7913<pre>
7914 declare i8* @llvm.adjust.trampoline(i8* &lt;tramp&gt;)
7915</pre>
7916
7917<h5>Overview:</h5>
7918<p>This performs any required machine-specific adjustment to the address of a
7919 trampoline (passed as <tt>tramp</tt>).</p>
7920
7921<h5>Arguments:</h5>
7922<p><tt>tramp</tt> must point to a block of memory which already has trampoline code
7923 filled in by a previous call to <a href="#int_it"><tt>llvm.init.trampoline</tt>
7924 </a>.</p>
7925
7926<h5>Semantics:</h5>
7927<p>On some architectures the address of the code to be executed needs to be
7928 different to the address where the trampoline is actually stored. This
7929 intrinsic returns the executable address corresponding to <tt>tramp</tt>
7930 after performing the required machine specific adjustments.
7931 The pointer returned can then be <a href="#int_trampoline"> bitcast and
7932 executed</a>.
7933</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7934
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]7935</div>
7936
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7937</div>
7938
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]7939<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7940<h3>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7941 <a name="int_memorymarkers">Memory Use Markers</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7942</h3>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7943
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7944<div>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7945
7946<p>This class of intrinsics exists to information about the lifetime of memory
7947 objects and ranges where variables are immutable.</p>
7948
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7949<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7950<h4>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7951 <a name="int_lifetime_start">'<tt>llvm.lifetime.start</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7952</h4>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7953
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7954<div>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7955
7956<h5>Syntax:</h5>
7957<pre>
7958 declare void @llvm.lifetime.start(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7959</pre>
7960
7961<h5>Overview:</h5>
7962<p>The '<tt>llvm.lifetime.start</tt>' intrinsic specifies the start of a memory
7963 object's lifetime.</p>
7964
7965<h5>Arguments:</h5>
Nick Lewycky321333e2009-10-13 07:57:33 +0000[diff] [blame]7966<p>The first argument is a constant integer representing the size of the
7967 object, or -1 if it is variable sized. The second argument is a pointer to
7968 the object.</p>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7969
7970<h5>Semantics:</h5>
7971<p>This intrinsic indicates that before this point in the code, the value of the
7972 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]7973 never be used and has an undefined value. A load from the pointer that
7974 precedes this intrinsic can be replaced with
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7975 <tt>'<a href="#undefvalues">undef</a>'</tt>.</p>
7976
7977</div>
7978
7979<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7980<h4>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7981 <a name="int_lifetime_end">'<tt>llvm.lifetime.end</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7982</h4>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7983
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7984<div>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7985
7986<h5>Syntax:</h5>
7987<pre>
7988 declare void @llvm.lifetime.end(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7989</pre>
7990
7991<h5>Overview:</h5>
7992<p>The '<tt>llvm.lifetime.end</tt>' intrinsic specifies the end of a memory
7993 object's lifetime.</p>
7994
7995<h5>Arguments:</h5>
Nick Lewycky321333e2009-10-13 07:57:33 +0000[diff] [blame]7996<p>The first argument is a constant integer representing the size of the
7997 object, or -1 if it is variable sized. The second argument is a pointer to
7998 the object.</p>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7999
8000<h5>Semantics:</h5>
8001<p>This intrinsic indicates that after this point in the code, the value of the
8002 memory pointed to by <tt>ptr</tt> is dead. This means that it is known to
8003 never be used and has an undefined value. Any stores into the memory object
8004 following this intrinsic may be removed as dead.
8005
8006</div>
8007
8008<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8009<h4>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]8010 <a name="int_invariant_start">'<tt>llvm.invariant.start</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8011</h4>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]8012
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8013<div>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]8014
8015<h5>Syntax:</h5>
8016<pre>
Nick Lewycky29b6cb42010-11-30 04:13:41 +0000[diff] [blame]8017 declare {}* @llvm.invariant.start(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]8018</pre>
8019
8020<h5>Overview:</h5>
8021<p>The '<tt>llvm.invariant.start</tt>' intrinsic specifies that the contents of
8022 a memory object will not change.</p>
8023
8024<h5>Arguments:</h5>
Nick Lewycky321333e2009-10-13 07:57:33 +0000[diff] [blame]8025<p>The first argument is a constant integer representing the size of the
8026 object, or -1 if it is variable sized. The second argument is a pointer to
8027 the object.</p>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]8028
8029<h5>Semantics:</h5>
8030<p>This intrinsic indicates that until an <tt>llvm.invariant.end</tt> that uses
8031 the return value, the referenced memory location is constant and
8032 unchanging.</p>
8033
8034</div>
8035
8036<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8037<h4>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]8038 <a name="int_invariant_end">'<tt>llvm.invariant.end</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8039</h4>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]8040
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8041<div>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]8042
8043<h5>Syntax:</h5>
8044<pre>
8045 declare void @llvm.invariant.end({}* &lt;start&gt;, i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
8046</pre>
8047
8048<h5>Overview:</h5>
8049<p>The '<tt>llvm.invariant.end</tt>' intrinsic specifies that the contents of
8050 a memory object are mutable.</p>
8051
8052<h5>Arguments:</h5>
8053<p>The first argument is the matching <tt>llvm.invariant.start</tt> intrinsic.
Nick Lewycky321333e2009-10-13 07:57:33 +0000[diff] [blame]8054 The second argument is a constant integer representing the size of the
8055 object, or -1 if it is variable sized and the third argument is a pointer
8056 to the object.</p>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]8057
8058<h5>Semantics:</h5>
8059<p>This intrinsic indicates that the memory is mutable again.</p>
8060
8061</div>
8062
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8063</div>
8064
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]8065<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8066<h3>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]8067 <a name="int_general">General Intrinsics</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8068</h3>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]8069
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8070<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8071
8072<p>This class of intrinsics is designed to be generic and has no specific
8073 purpose.</p>
8074
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]8075<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8076<h4>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]8077 <a name="int_var_annotation">'<tt>llvm.var.annotation</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8078</h4>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]8079
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8080<div>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]8081
8082<h5>Syntax:</h5>
8083<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]8084 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]8085</pre>
8086
8087<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8088<p>The '<tt>llvm.var.annotation</tt>' intrinsic.</p>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]8089
8090<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8091<p>The first argument is a pointer to a value, the second is a pointer to a
8092 global string, the third is a pointer to a global string which is the source
8093 file name, and the last argument is the line number.</p>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]8094
8095<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8096<p>This intrinsic allows annotation of local variables with arbitrary strings.
8097 This can be useful for special purpose optimizations that want to look for
John Criswelle865c032011-08-19 16:57:55 +0000[diff] [blame]8098 these annotations. These have no other defined use; they are ignored by code
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8099 generation and optimization.</p>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]8100
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]8101</div>
8102
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]8103<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8104<h4>
Tanya Lattnere1a8da02007-09-21 23:57:59 +0000[diff] [blame]8105 <a name="int_annotation">'<tt>llvm.annotation.*</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8106</h4>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]8107
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8108<div>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]8109
8110<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8111<p>This is an overloaded intrinsic. You can use '<tt>llvm.annotation</tt>' on
8112 any integer bit width.</p>
8113
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]8114<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]8115 declare i8 @llvm.annotation.i8(i8 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
8116 declare i16 @llvm.annotation.i16(i16 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
8117 declare i32 @llvm.annotation.i32(i32 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
8118 declare i64 @llvm.annotation.i64(i64 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
8119 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]8120</pre>
8121
8122<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8123<p>The '<tt>llvm.annotation</tt>' intrinsic.</p>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]8124
8125<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8126<p>The first argument is an integer value (result of some expression), the
8127 second is a pointer to a global string, the third is a pointer to a global
8128 string which is the source file name, and the last argument is the line
8129 number. It returns the value of the first argument.</p>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]8130
8131<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8132<p>This intrinsic allows annotations to be put on arbitrary expressions with
8133 arbitrary strings. This can be useful for special purpose optimizations that
John Criswelle865c032011-08-19 16:57:55 +0000[diff] [blame]8134 want to look for these annotations. These have no other defined use; they
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8135 are ignored by code generation and optimization.</p>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]8136
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]8137</div>
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]8138
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]8139<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8140<h4>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]8141 <a name="int_trap">'<tt>llvm.trap</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8142</h4>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]8143
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8144<div>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]8145
8146<h5>Syntax:</h5>
8147<pre>
8148 declare void @llvm.trap()
8149</pre>
8150
8151<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8152<p>The '<tt>llvm.trap</tt>' intrinsic.</p>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]8153
8154<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8155<p>None.</p>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]8156
8157<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8158<p>This intrinsics is lowered to the target dependent trap instruction. If the
8159 target does not have a trap instruction, this intrinsic will be lowered to
8160 the call of the <tt>abort()</tt> function.</p>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]8161
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]8162</div>
8163
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]8164<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8165<h4>
Misha Brukmandccb0252008-11-22 23:55:29 +0000[diff] [blame]8166 <a name="int_stackprotector">'<tt>llvm.stackprotector</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8167</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8168
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8169<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8170
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]8171<h5>Syntax:</h5>
8172<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]8173 declare void @llvm.stackprotector(i8* &lt;guard&gt;, i8** &lt;slot&gt;)
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]8174</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8175
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]8176<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8177<p>The <tt>llvm.stackprotector</tt> intrinsic takes the <tt>guard</tt> and
8178 stores it onto the stack at <tt>slot</tt>. The stack slot is adjusted to
8179 ensure that it is placed on the stack before local variables.</p>
8180
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]8181<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8182<p>The <tt>llvm.stackprotector</tt> intrinsic requires two pointer
8183 arguments. The first argument is the value loaded from the stack
8184 guard <tt>@__stack_chk_guard</tt>. The second variable is an <tt>alloca</tt>
8185 that has enough space to hold the value of the guard.</p>
8186
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]8187<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8188<p>This intrinsic causes the prologue/epilogue inserter to force the position of
8189 the <tt>AllocaInst</tt> stack slot to be before local variables on the
8190 stack. This is to ensure that if a local variable on the stack is
8191 overwritten, it will destroy the value of the guard. When the function exits,
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]8192 the guard on the stack is checked against the original guard. If they are
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8193 different, then the program aborts by calling the <tt>__stack_chk_fail()</tt>
8194 function.</p>
8195
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]8196</div>
8197
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]8198<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8199<h4>
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]8200 <a name="int_objectsize">'<tt>llvm.objectsize</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8201</h4>
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]8202
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8203<div>
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]8204
8205<h5>Syntax:</h5>
8206<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]8207 declare i32 @llvm.objectsize.i32(i8* &lt;object&gt;, i1 &lt;type&gt;)
8208 declare i64 @llvm.objectsize.i64(i8* &lt;object&gt;, i1 &lt;type&gt;)
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]8209</pre>
8210
8211<h5>Overview:</h5>
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]8212<p>The <tt>llvm.objectsize</tt> intrinsic is designed to provide information to
8213 the optimizers to determine at compile time whether a) an operation (like
8214 memcpy) will overflow a buffer that corresponds to an object, or b) that a
8215 runtime check for overflow isn't necessary. An object in this context means
8216 an allocation of a specific class, structure, array, or other object.</p>
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]8217
8218<h5>Arguments:</h5>
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]8219<p>The <tt>llvm.objectsize</tt> intrinsic takes two arguments. The first
Eric Christopher8295a0a2009-12-23 00:29:49 +0000[diff] [blame]8220 argument is a pointer to or into the <tt>object</tt>. The second argument
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]8221 is a boolean 0 or 1. This argument determines whether you want the
8222 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]8223 1, variables are not allowed.</p>
8224
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]8225<h5>Semantics:</h5>
8226<p>The <tt>llvm.objectsize</tt> intrinsic is lowered to either a constant
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]8227 representing the size of the object concerned, or <tt>i32/i64 -1 or 0</tt>,
8228 depending on the <tt>type</tt> argument, if the size cannot be determined at
8229 compile time.</p>
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]8230
8231</div>
Jakub Staszakb170e2d2011-12-04 18:29:26 +0000[diff] [blame]8232<!-- _______________________________________________________________________ -->
8233<h4>
8234 <a name="int_expect">'<tt>llvm.expect</tt>' Intrinsic</a>
8235</h4>
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]8236
Jakub Staszakb170e2d2011-12-04 18:29:26 +0000[diff] [blame]8237<div>
8238
8239<h5>Syntax:</h5>
8240<pre>
8241 declare i32 @llvm.expect.i32(i32 &lt;val&gt;, i32 &lt;expected_val&gt;)
8242 declare i64 @llvm.expect.i64(i64 &lt;val&gt;, i64 &lt;expected_val&gt;)
8243</pre>
8244
8245<h5>Overview:</h5>
8246<p>The <tt>llvm.expect</tt> intrinsic provides information about expected (the
8247 most probable) value of <tt>val</tt>, which can be used by optimizers.</p>
8248
8249<h5>Arguments:</h5>
8250<p>The <tt>llvm.expect</tt> intrinsic takes two arguments. The first
8251 argument is a value. The second argument is an expected value, this needs to
8252 be a constant value, variables are not allowed.</p>
8253
8254<h5>Semantics:</h5>
8255<p>This intrinsic is lowered to the <tt>val</tt>.</p>
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8256</div>
8257
8258</div>
8259
Jakub Staszakb170e2d2011-12-04 18:29:26 +0000[diff] [blame]8260</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]8261<!-- *********************************************************************** -->
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]8262<hr>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]8263<address>
8264 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
Misha Brukman44408702008-12-11 17:34:48 +0000[diff] [blame]8265 src="http://jigsaw.w3.org/css-validator/images/vcss-blue" alt="Valid CSS"></a>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]8266 <a href="http://validator.w3.org/check/referer"><img
Misha Brukman44408702008-12-11 17:34:48 +0000[diff] [blame]8267 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]8268
8269 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
NAKAMURA Takumib9a33632011-04-09 02:13:37 +0000[diff] [blame]8270 <a href="http://llvm.org/">The LLVM Compiler Infrastructure</a><br>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]8271 Last modified: $Date$
8272</address>
Chris Lattnerc7d3ab32008-01-04 04:33:49 +0000[diff] [blame]8273
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]8274</body>
8275</html>