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gerrit-public.fairphone.software / platform / external / llvm / 5c6e4df71323e3c3b6eb23bfd4b1d908ab5b149a / . / docs / LangRef.html
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4<head>
5 <title>LLVM Assembly Language Reference Manual</title>
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7 <meta name="author" content="Chris Lattner">
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]8 <meta name="description"
Reid Spencer3921c742004-08-26 20:44:00 +0000[diff] [blame]9 content="LLVM Assembly Language Reference Manual.">
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]10 <link rel="stylesheet" href="llvm.css" type="text/css">
11</head>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]12
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]13<body>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]14
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]15<h1>LLVM Language Reference Manual</h1>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]16<ol>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]17 <li><a href="#abstract">Abstract</a></li>
18 <li><a href="#introduction">Introduction</a></li>
19 <li><a href="#identifiers">Identifiers</a></li>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]20 <li><a href="#highlevel">High Level Structure</a>
21 <ol>
22 <li><a href="#modulestructure">Module Structure</a></li>
Bill Wendling3d10a5a2009-07-20 01:03:30 +0000[diff] [blame]23 <li><a href="#linkage">Linkage Types</a>
24 <ol>
Bill Wendling987e7eb2009-07-20 02:41:50 +0000[diff] [blame]25 <li><a href="#linkage_private">'<tt>private</tt>' Linkage</a></li>
26 <li><a href="#linkage_linker_private">'<tt>linker_private</tt>' Linkage</a></li>
Bill Wendling5e721d72010-07-01 21:55:59 +0000[diff] [blame]27 <li><a href="#linkage_linker_private_weak">'<tt>linker_private_weak</tt>' Linkage</a></li>
Bill Wendling55ae5152010-08-20 22:05:50 +0000[diff] [blame]28 <li><a href="#linkage_linker_private_weak_def_auto">'<tt>linker_private_weak_def_auto</tt>' Linkage</a></li>
Bill Wendling987e7eb2009-07-20 02:41:50 +0000[diff] [blame]29 <li><a href="#linkage_internal">'<tt>internal</tt>' Linkage</a></li>
30 <li><a href="#linkage_available_externally">'<tt>available_externally</tt>' Linkage</a></li>
31 <li><a href="#linkage_linkonce">'<tt>linkonce</tt>' Linkage</a></li>
32 <li><a href="#linkage_common">'<tt>common</tt>' Linkage</a></li>
33 <li><a href="#linkage_weak">'<tt>weak</tt>' Linkage</a></li>
34 <li><a href="#linkage_appending">'<tt>appending</tt>' Linkage</a></li>
35 <li><a href="#linkage_externweak">'<tt>extern_weak</tt>' Linkage</a></li>
Chris Lattner5a2d8752009-10-10 18:26:06 +0000[diff] [blame]36 <li><a href="#linkage_linkonce_odr">'<tt>linkonce_odr</tt>' Linkage</a></li>
Bill Wendling987e7eb2009-07-20 02:41:50 +0000[diff] [blame]37 <li><a href="#linkage_weak">'<tt>weak_odr</tt>' Linkage</a></li>
Bill Wendlingf7f06102011-10-11 06:41:28 +0000[diff] [blame]38 <li><a href="#linkage_external">'<tt>external</tt>' Linkage</a></li>
Bill Wendling987e7eb2009-07-20 02:41:50 +0000[diff] [blame]39 <li><a href="#linkage_dllimport">'<tt>dllimport</tt>' Linkage</a></li>
40 <li><a href="#linkage_dllexport">'<tt>dllexport</tt>' Linkage</a></li>
Bill Wendling3d10a5a2009-07-20 01:03:30 +0000[diff] [blame]41 </ol>
42 </li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]43 <li><a href="#callingconv">Calling Conventions</a></li>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]44 <li><a href="#namedtypes">Named Types</a></li>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]45 <li><a href="#globalvars">Global Variables</a></li>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]46 <li><a href="#functionstructure">Functions</a></li>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]47 <li><a href="#aliasstructure">Aliases</a></li>
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]48 <li><a href="#namedmetadatastructure">Named Metadata</a></li>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]49 <li><a href="#paramattrs">Parameter Attributes</a></li>
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]50 <li><a href="#fnattrs">Function Attributes</a></li>
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]51 <li><a href="#gc">Garbage Collector Names</a></li>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]52 <li><a href="#moduleasm">Module-Level Inline Assembly</a></li>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]53 <li><a href="#datalayout">Data Layout</a></li>
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]54 <li><a href="#pointeraliasing">Pointer Aliasing Rules</a></li>
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]55 <li><a href="#volatile">Volatile Memory Accesses</a></li>
Eli Friedman5b60e1b2011-07-20 21:35:53 +0000[diff] [blame]56 <li><a href="#memmodel">Memory Model for Concurrent Operations</a></li>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]57 <li><a href="#ordering">Atomic Memory Ordering Constraints</a></li>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]58 </ol>
59 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]60 <li><a href="#typesystem">Type System</a>
61 <ol>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]62 <li><a href="#t_classifications">Type Classifications</a></li>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]63 <li><a href="#t_primitive">Primitive Types</a>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]64 <ol>
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]65 <li><a href="#t_integer">Integer Type</a></li>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]66 <li><a href="#t_floating">Floating Point Types</a></li>
Dale Johannesen21fe99b2010-10-01 00:48:59 +0000[diff] [blame]67 <li><a href="#t_x86mmx">X86mmx Type</a></li>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]68 <li><a href="#t_void">Void Type</a></li>
69 <li><a href="#t_label">Label Type</a></li>
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]70 <li><a href="#t_metadata">Metadata Type</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]71 </ol>
72 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]73 <li><a href="#t_derived">Derived Types</a>
74 <ol>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]75 <li><a href="#t_aggregate">Aggregate Types</a>
76 <ol>
77 <li><a href="#t_array">Array Type</a></li>
78 <li><a href="#t_struct">Structure Type</a></li>
Chris Lattner628ed392011-07-23 19:59:08 +0000[diff] [blame]79 <li><a href="#t_opaque">Opaque Structure Types</a></li>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]80 <li><a href="#t_vector">Vector Type</a></li>
81 </ol>
82 </li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]83 <li><a href="#t_function">Function Type</a></li>
84 <li><a href="#t_pointer">Pointer Type</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]85 </ol>
86 </li>
87 </ol>
88 </li>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]89 <li><a href="#constants">Constants</a>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]90 <ol>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]91 <li><a href="#simpleconstants">Simple Constants</a></li>
Chris Lattner70882792009-02-28 18:32:25 +0000[diff] [blame]92 <li><a href="#complexconstants">Complex Constants</a></li>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]93 <li><a href="#globalconstants">Global Variable and Function Addresses</a></li>
94 <li><a href="#undefvalues">Undefined Values</a></li>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]95 <li><a href="#trapvalues">Trap Values</a></li>
Chris Lattnerf9d078e2009-10-27 21:19:13 +0000[diff] [blame]96 <li><a href="#blockaddress">Addresses of Basic Blocks</a></li>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]97 <li><a href="#constantexprs">Constant Expressions</a></li>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]98 </ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]99 </li>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]100 <li><a href="#othervalues">Other Values</a>
101 <ol>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]102 <li><a href="#inlineasm">Inline Assembler Expressions</a></li>
Peter Collingbourne249d9532011-10-27 19:19:07 +0000[diff] [blame]103 <li><a href="#metadata">Metadata Nodes and Metadata Strings</a>
104 <ol>
105 <li><a href="#tbaa">'<tt>tbaa</tt>' Metadata</a></li>
Peter Collingbourne999f90b2011-10-27 19:19:14 +0000[diff] [blame]106 <li><a href="#fpaccuracy">'<tt>fpaccuracy</tt>' Metadata</a></li>
Peter Collingbourne249d9532011-10-27 19:19:07 +0000[diff] [blame]107 </ol>
108 </li>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]109 </ol>
110 </li>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]111 <li><a href="#intrinsic_globals">Intrinsic Global Variables</a>
112 <ol>
113 <li><a href="#intg_used">The '<tt>llvm.used</tt>' Global Variable</a></li>
Chris Lattner401e10c2009-07-20 06:14:25 +0000[diff] [blame]114 <li><a href="#intg_compiler_used">The '<tt>llvm.compiler.used</tt>'
115 Global Variable</a></li>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]116 <li><a href="#intg_global_ctors">The '<tt>llvm.global_ctors</tt>'
117 Global Variable</a></li>
118 <li><a href="#intg_global_dtors">The '<tt>llvm.global_dtors</tt>'
119 Global Variable</a></li>
120 </ol>
121 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]122 <li><a href="#instref">Instruction Reference</a>
123 <ol>
124 <li><a href="#terminators">Terminator Instructions</a>
125 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]126 <li><a href="#i_ret">'<tt>ret</tt>' Instruction</a></li>
127 <li><a href="#i_br">'<tt>br</tt>' Instruction</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]128 <li><a href="#i_switch">'<tt>switch</tt>' Instruction</a></li>
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]129 <li><a href="#i_indirectbr">'<tt>indirectbr</tt>' Instruction</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]130 <li><a href="#i_invoke">'<tt>invoke</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]131 <li><a href="#i_unwind">'<tt>unwind</tt>' Instruction</a></li>
Bill Wendlingdccc03b2011-07-31 06:30:59 +0000[diff] [blame]132 <li><a href="#i_resume">'<tt>resume</tt>' Instruction</a></li>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]133 <li><a href="#i_unreachable">'<tt>unreachable</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]134 </ol>
135 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]136 <li><a href="#binaryops">Binary Operations</a>
137 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]138 <li><a href="#i_add">'<tt>add</tt>' Instruction</a></li>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]139 <li><a href="#i_fadd">'<tt>fadd</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]140 <li><a href="#i_sub">'<tt>sub</tt>' Instruction</a></li>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]141 <li><a href="#i_fsub">'<tt>fsub</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]142 <li><a href="#i_mul">'<tt>mul</tt>' Instruction</a></li>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]143 <li><a href="#i_fmul">'<tt>fmul</tt>' Instruction</a></li>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]144 <li><a href="#i_udiv">'<tt>udiv</tt>' Instruction</a></li>
145 <li><a href="#i_sdiv">'<tt>sdiv</tt>' Instruction</a></li>
146 <li><a href="#i_fdiv">'<tt>fdiv</tt>' Instruction</a></li>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]147 <li><a href="#i_urem">'<tt>urem</tt>' Instruction</a></li>
148 <li><a href="#i_srem">'<tt>srem</tt>' Instruction</a></li>
149 <li><a href="#i_frem">'<tt>frem</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]150 </ol>
151 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]152 <li><a href="#bitwiseops">Bitwise Binary Operations</a>
153 <ol>
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]154 <li><a href="#i_shl">'<tt>shl</tt>' Instruction</a></li>
155 <li><a href="#i_lshr">'<tt>lshr</tt>' Instruction</a></li>
156 <li><a href="#i_ashr">'<tt>ashr</tt>' Instruction</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]157 <li><a href="#i_and">'<tt>and</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]158 <li><a href="#i_or">'<tt>or</tt>' Instruction</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]159 <li><a href="#i_xor">'<tt>xor</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]160 </ol>
161 </li>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]162 <li><a href="#vectorops">Vector Operations</a>
163 <ol>
164 <li><a href="#i_extractelement">'<tt>extractelement</tt>' Instruction</a></li>
165 <li><a href="#i_insertelement">'<tt>insertelement</tt>' Instruction</a></li>
166 <li><a href="#i_shufflevector">'<tt>shufflevector</tt>' Instruction</a></li>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]167 </ol>
168 </li>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]169 <li><a href="#aggregateops">Aggregate Operations</a>
170 <ol>
171 <li><a href="#i_extractvalue">'<tt>extractvalue</tt>' Instruction</a></li>
172 <li><a href="#i_insertvalue">'<tt>insertvalue</tt>' Instruction</a></li>
173 </ol>
174 </li>
Chris Lattner884a9702006-08-15 00:45:58 +0000[diff] [blame]175 <li><a href="#memoryops">Memory Access and Addressing Operations</a>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]176 <ol>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]177 <li><a href="#i_alloca">'<tt>alloca</tt>' Instruction</a></li>
178 <li><a href="#i_load">'<tt>load</tt>' Instruction</a></li>
179 <li><a href="#i_store">'<tt>store</tt>' Instruction</a></li>
180 <li><a href="#i_fence">'<tt>fence</tt>' Instruction</a></li>
181 <li><a href="#i_cmpxchg">'<tt>cmpxchg</tt>' Instruction</a></li>
182 <li><a href="#i_atomicrmw">'<tt>atomicrmw</tt>' Instruction</a></li>
Robert Bocchino7b81c752006-02-17 21:18:08 +0000[diff] [blame]183 <li><a href="#i_getelementptr">'<tt>getelementptr</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]184 </ol>
185 </li>
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]186 <li><a href="#convertops">Conversion Operations</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]187 <ol>
188 <li><a href="#i_trunc">'<tt>trunc .. to</tt>' Instruction</a></li>
189 <li><a href="#i_zext">'<tt>zext .. to</tt>' Instruction</a></li>
190 <li><a href="#i_sext">'<tt>sext .. to</tt>' Instruction</a></li>
191 <li><a href="#i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a></li>
192 <li><a href="#i_fpext">'<tt>fpext .. to</tt>' Instruction</a></li>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]193 <li><a href="#i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a></li>
194 <li><a href="#i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a></li>
195 <li><a href="#i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a></li>
196 <li><a href="#i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a></li>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]197 <li><a href="#i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a></li>
198 <li><a href="#i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a></li>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]199 <li><a href="#i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a></li>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]200 </ol>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]201 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]202 <li><a href="#otherops">Other Operations</a>
203 <ol>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]204 <li><a href="#i_icmp">'<tt>icmp</tt>' Instruction</a></li>
205 <li><a href="#i_fcmp">'<tt>fcmp</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]206 <li><a href="#i_phi">'<tt>phi</tt>' Instruction</a></li>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]207 <li><a href="#i_select">'<tt>select</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]208 <li><a href="#i_call">'<tt>call</tt>' Instruction</a></li>
Chris Lattnerfb6977d2006-01-13 23:26:01 +0000[diff] [blame]209 <li><a href="#i_va_arg">'<tt>va_arg</tt>' Instruction</a></li>
Bill Wendlingf78faf82011-08-02 21:52:38 +0000[diff] [blame]210 <li><a href="#i_landingpad">'<tt>landingpad</tt>' Instruction</a></li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]211 </ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]212 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]213 </ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]214 </li>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]215 <li><a href="#intrinsics">Intrinsic Functions</a>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]216 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]217 <li><a href="#int_varargs">Variable Argument Handling Intrinsics</a>
218 <ol>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]219 <li><a href="#int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a></li>
220 <li><a href="#int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a></li>
221 <li><a href="#int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]222 </ol>
223 </li>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]224 <li><a href="#int_gc">Accurate Garbage Collection Intrinsics</a>
225 <ol>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]226 <li><a href="#int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a></li>
227 <li><a href="#int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a></li>
228 <li><a href="#int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a></li>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]229 </ol>
230 </li>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]231 <li><a href="#int_codegen">Code Generator Intrinsics</a>
232 <ol>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]233 <li><a href="#int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a></li>
234 <li><a href="#int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a></li>
235 <li><a href="#int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a></li>
236 <li><a href="#int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a></li>
237 <li><a href="#int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a></li>
238 <li><a href="#int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a></li>
Dan Gohman31f1af12010-05-26 21:56:15 +0000[diff] [blame]239 <li><a href="#int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a></li>
John Criswell7123e272004-04-09 16:43:20 +0000[diff] [blame]240 </ol>
241 </li>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]242 <li><a href="#int_libc">Standard C Library Intrinsics</a>
243 <ol>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]244 <li><a href="#int_memcpy">'<tt>llvm.memcpy.*</tt>' Intrinsic</a></li>
245 <li><a href="#int_memmove">'<tt>llvm.memmove.*</tt>' Intrinsic</a></li>
246 <li><a href="#int_memset">'<tt>llvm.memset.*</tt>' Intrinsic</a></li>
247 <li><a href="#int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a></li>
248 <li><a href="#int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a></li>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]249 <li><a href="#int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a></li>
250 <li><a href="#int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a></li>
251 <li><a href="#int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a></li>
Dan Gohman08b280b2011-05-27 00:36:31 +0000[diff] [blame]252 <li><a href="#int_exp">'<tt>llvm.exp.*</tt>' Intrinsic</a></li>
253 <li><a href="#int_log">'<tt>llvm.log.*</tt>' Intrinsic</a></li>
Cameron Zwarich33390842011-07-08 21:39:21 +0000[diff] [blame]254 <li><a href="#int_fma">'<tt>llvm.fma.*</tt>' Intrinsic</a></li>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]255 </ol>
256 </li>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]257 <li><a href="#int_manip">Bit Manipulation Intrinsics</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]258 <ol>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]259 <li><a href="#int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a></li>
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]260 <li><a href="#int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic </a></li>
261 <li><a href="#int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic </a></li>
262 <li><a href="#int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic </a></li>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]263 </ol>
264 </li>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]265 <li><a href="#int_overflow">Arithmetic with Overflow Intrinsics</a>
266 <ol>
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]267 <li><a href="#int_sadd_overflow">'<tt>llvm.sadd.with.overflow.*</tt> Intrinsics</a></li>
268 <li><a href="#int_uadd_overflow">'<tt>llvm.uadd.with.overflow.*</tt> Intrinsics</a></li>
269 <li><a href="#int_ssub_overflow">'<tt>llvm.ssub.with.overflow.*</tt> Intrinsics</a></li>
270 <li><a href="#int_usub_overflow">'<tt>llvm.usub.with.overflow.*</tt> Intrinsics</a></li>
271 <li><a href="#int_smul_overflow">'<tt>llvm.smul.with.overflow.*</tt> Intrinsics</a></li>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]272 <li><a href="#int_umul_overflow">'<tt>llvm.umul.with.overflow.*</tt> Intrinsics</a></li>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]273 </ol>
274 </li>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]275 <li><a href="#int_fp16">Half Precision Floating Point Intrinsics</a>
276 <ol>
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]277 <li><a href="#int_convert_to_fp16">'<tt>llvm.convert.to.fp16</tt>' Intrinsic</a></li>
278 <li><a href="#int_convert_from_fp16">'<tt>llvm.convert.from.fp16</tt>' Intrinsic</a></li>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]279 </ol>
280 </li>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]281 <li><a href="#int_debugger">Debugger intrinsics</a></li>
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]282 <li><a href="#int_eh">Exception Handling intrinsics</a></li>
Duncan Sands4a544a72011-09-06 13:37:06 +0000[diff] [blame]283 <li><a href="#int_trampoline">Trampoline Intrinsics</a>
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]284 <ol>
285 <li><a href="#int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a></li>
Duncan Sands4a544a72011-09-06 13:37:06 +0000[diff] [blame]286 <li><a href="#int_at">'<tt>llvm.adjust.trampoline</tt>' Intrinsic</a></li>
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]287 </ol>
288 </li>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]289 <li><a href="#int_memorymarkers">Memory Use Markers</a>
290 <ol>
291 <li><a href="#int_lifetime_start"><tt>llvm.lifetime.start</tt></a></li>
292 <li><a href="#int_lifetime_end"><tt>llvm.lifetime.end</tt></a></li>
293 <li><a href="#int_invariant_start"><tt>llvm.invariant.start</tt></a></li>
294 <li><a href="#int_invariant_end"><tt>llvm.invariant.end</tt></a></li>
295 </ol>
296 </li>
Reid Spencer20677642007-07-20 19:59:11 +0000[diff] [blame]297 <li><a href="#int_general">General intrinsics</a>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]298 <ol>
Reid Spencer20677642007-07-20 19:59:11 +0000[diff] [blame]299 <li><a href="#int_var_annotation">
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]300 '<tt>llvm.var.annotation</tt>' Intrinsic</a></li>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]301 <li><a href="#int_annotation">
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]302 '<tt>llvm.annotation.*</tt>' Intrinsic</a></li>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]303 <li><a href="#int_trap">
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]304 '<tt>llvm.trap</tt>' Intrinsic</a></li>
305 <li><a href="#int_stackprotector">
306 '<tt>llvm.stackprotector</tt>' Intrinsic</a></li>
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]307 <li><a href="#int_objectsize">
308 '<tt>llvm.objectsize</tt>' Intrinsic</a></li>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]309 </ol>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]310 </li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]311 </ol>
312 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]313</ol>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]314
315<div class="doc_author">
316 <p>Written by <a href="mailto:sabre@nondot.org">Chris Lattner</a>
317 and <a href="mailto:vadve@cs.uiuc.edu">Vikram Adve</a></p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]318</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]319
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]320<!-- *********************************************************************** -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]321<h2><a name="abstract">Abstract</a></h2>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]322<!-- *********************************************************************** -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]323
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]324<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]325
326<p>This document is a reference manual for the LLVM assembly language. LLVM is
327 a Static Single Assignment (SSA) based representation that provides type
328 safety, low-level operations, flexibility, and the capability of representing
329 'all' high-level languages cleanly. It is the common code representation
330 used throughout all phases of the LLVM compilation strategy.</p>
331
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]332</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]333
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]334<!-- *********************************************************************** -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]335<h2><a name="introduction">Introduction</a></h2>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]336<!-- *********************************************************************** -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]337
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]338<div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]339
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]340<p>The LLVM code representation is designed to be used in three different forms:
341 as an in-memory compiler IR, as an on-disk bitcode representation (suitable
342 for fast loading by a Just-In-Time compiler), and as a human readable
343 assembly language representation. This allows LLVM to provide a powerful
344 intermediate representation for efficient compiler transformations and
345 analysis, while providing a natural means to debug and visualize the
346 transformations. The three different forms of LLVM are all equivalent. This
347 document describes the human readable representation and notation.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]348
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]349<p>The LLVM representation aims to be light-weight and low-level while being
350 expressive, typed, and extensible at the same time. It aims to be a
351 "universal IR" of sorts, by being at a low enough level that high-level ideas
352 may be cleanly mapped to it (similar to how microprocessors are "universal
353 IR's", allowing many source languages to be mapped to them). By providing
354 type information, LLVM can be used as the target of optimizations: for
355 example, through pointer analysis, it can be proven that a C automatic
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]356 variable is never accessed outside of the current function, allowing it to
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]357 be promoted to a simple SSA value instead of a memory location.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]358
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]359<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]360<h4>
361 <a name="wellformed">Well-Formedness</a>
362</h4>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]363
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]364<div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]365
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]366<p>It is important to note that this document describes 'well formed' LLVM
367 assembly language. There is a difference between what the parser accepts and
368 what is considered 'well formed'. For example, the following instruction is
369 syntactically okay, but not well formed:</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]370
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]371<pre class="doc_code">
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]372%x = <a href="#i_add">add</a> i32 1, %x
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]373</pre>
374
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]375<p>because the definition of <tt>%x</tt> does not dominate all of its uses. The
376 LLVM infrastructure provides a verification pass that may be used to verify
377 that an LLVM module is well formed. This pass is automatically run by the
378 parser after parsing input assembly and by the optimizer before it outputs
379 bitcode. The violations pointed out by the verifier pass indicate bugs in
380 transformation passes or input to the parser.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]381
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]382</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]383
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]384</div>
385
Chris Lattnercc689392007-10-03 17:34:29 +0000[diff] [blame]386<!-- Describe the typesetting conventions here. -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]387
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]388<!-- *********************************************************************** -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]389<h2><a name="identifiers">Identifiers</a></h2>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]390<!-- *********************************************************************** -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]391
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]392<div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]393
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]394<p>LLVM identifiers come in two basic types: global and local. Global
395 identifiers (functions, global variables) begin with the <tt>'@'</tt>
396 character. Local identifiers (register names, types) begin with
397 the <tt>'%'</tt> character. Additionally, there are three different formats
398 for identifiers, for different purposes:</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]399
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]400<ol>
Reid Spencer2c452282007-08-07 14:34:28 +0000[diff] [blame]401 <li>Named values are represented as a string of characters with their prefix.
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]402 For example, <tt>%foo</tt>, <tt>@DivisionByZero</tt>,
403 <tt>%a.really.long.identifier</tt>. The actual regular expression used is
404 '<tt>[%@][a-zA-Z$._][a-zA-Z$._0-9]*</tt>'. Identifiers which require
405 other characters in their names can be surrounded with quotes. Special
406 characters may be escaped using <tt>"\xx"</tt> where <tt>xx</tt> is the
407 ASCII code for the character in hexadecimal. In this way, any character
408 can be used in a name value, even quotes themselves.</li>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]409
Reid Spencer2c452282007-08-07 14:34:28 +0000[diff] [blame]410 <li>Unnamed values are represented as an unsigned numeric value with their
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]411 prefix. For example, <tt>%12</tt>, <tt>@2</tt>, <tt>%44</tt>.</li>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]412
Reid Spencercc16dc32004-12-09 18:02:53 +0000[diff] [blame]413 <li>Constants, which are described in a <a href="#constants">section about
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]414 constants</a>, below.</li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]415</ol>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]416
Reid Spencer2c452282007-08-07 14:34:28 +0000[diff] [blame]417<p>LLVM requires that values start with a prefix for two reasons: Compilers
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]418 don't need to worry about name clashes with reserved words, and the set of
419 reserved words may be expanded in the future without penalty. Additionally,
420 unnamed identifiers allow a compiler to quickly come up with a temporary
421 variable without having to avoid symbol table conflicts.</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]422
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]423<p>Reserved words in LLVM are very similar to reserved words in other
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]424 languages. There are keywords for different opcodes
425 ('<tt><a href="#i_add">add</a></tt>',
426 '<tt><a href="#i_bitcast">bitcast</a></tt>',
427 '<tt><a href="#i_ret">ret</a></tt>', etc...), for primitive type names
428 ('<tt><a href="#t_void">void</a></tt>',
429 '<tt><a href="#t_primitive">i32</a></tt>', etc...), and others. These
430 reserved words cannot conflict with variable names, because none of them
431 start with a prefix character (<tt>'%'</tt> or <tt>'@'</tt>).</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]432
433<p>Here is an example of LLVM code to multiply the integer variable
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]434 '<tt>%X</tt>' by 8:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]435
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]436<p>The easy way:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]437
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]438<pre class="doc_code">
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]439%result = <a href="#i_mul">mul</a> i32 %X, 8
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]440</pre>
441
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]442<p>After strength reduction:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]443
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]444<pre class="doc_code">
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]445%result = <a href="#i_shl">shl</a> i32 %X, i8 3
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]446</pre>
447
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]448<p>And the hard way:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]449
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]450<pre class="doc_code">
Gabor Greifec58f752009-10-28 13:05:07 +0000[diff] [blame]451%0 = <a href="#i_add">add</a> i32 %X, %X <i>; yields {i32}:%0</i>
452%1 = <a href="#i_add">add</a> i32 %0, %0 <i>; yields {i32}:%1</i>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]453%result = <a href="#i_add">add</a> i32 %1, %1
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]454</pre>
455
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]456<p>This last way of multiplying <tt>%X</tt> by 8 illustrates several important
457 lexical features of LLVM:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]458
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]459<ol>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]460 <li>Comments are delimited with a '<tt>;</tt>' and go until the end of
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]461 line.</li>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]462
463 <li>Unnamed temporaries are created when the result of a computation is not
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]464 assigned to a named value.</li>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]465
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]466 <li>Unnamed temporaries are numbered sequentially</li>
467</ol>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]468
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]469<p>It also shows a convention that we follow in this document. When
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]470 demonstrating instructions, we will follow an instruction with a comment that
471 defines the type and name of value produced. Comments are shown in italic
472 text.</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]473
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]474</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]475
476<!-- *********************************************************************** -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]477<h2><a name="highlevel">High Level Structure</a></h2>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]478<!-- *********************************************************************** -->
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]479<div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]480<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]481<h3>
482 <a name="modulestructure">Module Structure</a>
483</h3>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]484
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]485<div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]486
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]487<p>LLVM programs are composed of "Module"s, each of which is a translation unit
488 of the input programs. Each module consists of functions, global variables,
489 and symbol table entries. Modules may be combined together with the LLVM
490 linker, which merges function (and global variable) definitions, resolves
491 forward declarations, and merges symbol table entries. Here is an example of
492 the "hello world" module:</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]493
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]494<pre class="doc_code">
Chris Lattner63e4ccb2010-08-17 17:13:42 +0000[diff] [blame]495<i>; Declare the string constant as a global constant.</i>&nbsp;
Nick Lewyckydb9cd762011-01-29 01:09:53 +0000[diff] [blame]496<a href="#identifiers">@.LC0</a> = <a href="#linkage_internal">internal</a>&nbsp;<a href="#globalvars">constant</a>&nbsp;<a href="#t_array">[13 x i8]</a> c"hello world\0A\00" <i>; [13 x i8]*</i>&nbsp;
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]497
Chris Lattner63e4ccb2010-08-17 17:13:42 +0000[diff] [blame]498<i>; External declaration of the puts function</i>&nbsp;
499<a href="#functionstructure">declare</a> i32 @puts(i8*) <i>; i32 (i8*)* </i>&nbsp;
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]500
501<i>; Definition of main function</i>
Chris Lattner63e4ccb2010-08-17 17:13:42 +0000[diff] [blame]502define i32 @main() { <i>; i32()* </i>&nbsp;
503 <i>; Convert [13 x i8]* to i8 *...</i>&nbsp;
504 %cast210 = <a href="#i_getelementptr">getelementptr</a> [13 x i8]* @.LC0, i64 0, i64 0 <i>; i8*</i>&nbsp;
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]505
Chris Lattner63e4ccb2010-08-17 17:13:42 +0000[diff] [blame]506 <i>; Call puts function to write out the string to stdout.</i>&nbsp;
507 <a href="#i_call">call</a> i32 @puts(i8* %cast210) <i>; i32</i>&nbsp;
508 <a href="#i_ret">ret</a> i32 0&nbsp;
509}
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]510
511<i>; Named metadata</i>
512!1 = metadata !{i32 41}
513!foo = !{!1, null}
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]514</pre>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]515
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]516<p>This example is made up of a <a href="#globalvars">global variable</a> named
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]517 "<tt>.LC0</tt>", an external declaration of the "<tt>puts</tt>" function,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]518 a <a href="#functionstructure">function definition</a> for
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]519 "<tt>main</tt>" and <a href="#namedmetadatastructure">named metadata</a>
520 "<tt>foo"</tt>.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]521
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]522<p>In general, a module is made up of a list of global values, where both
523 functions and global variables are global values. Global values are
524 represented by a pointer to a memory location (in this case, a pointer to an
525 array of char, and a pointer to a function), and have one of the
526 following <a href="#linkage">linkage types</a>.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]527
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]528</div>
529
530<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]531<h3>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]532 <a name="linkage">Linkage Types</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]533</h3>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]534
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]535<div>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]536
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]537<p>All Global Variables and Functions have one of the following types of
538 linkage:</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]539
540<dl>
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]541 <dt><tt><b><a name="linkage_private">private</a></b></tt></dt>
Bill Wendling5e721d72010-07-01 21:55:59 +0000[diff] [blame]542 <dd>Global values with "<tt>private</tt>" linkage are only directly accessible
543 by objects in the current module. In particular, linking code into a
544 module with an private global value may cause the private to be renamed as
545 necessary to avoid collisions. Because the symbol is private to the
546 module, all references can be updated. This doesn't show up in any symbol
547 table in the object file.</dd>
Rafael Espindolabb46f522009-01-15 20:18:42 +0000[diff] [blame]548
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]549 <dt><tt><b><a name="linkage_linker_private">linker_private</a></b></tt></dt>
Bill Wendling5e721d72010-07-01 21:55:59 +0000[diff] [blame]550 <dd>Similar to <tt>private</tt>, but the symbol is passed through the
551 assembler and evaluated by the linker. Unlike normal strong symbols, they
552 are removed by the linker from the final linked image (executable or
553 dynamic library).</dd>
554
555 <dt><tt><b><a name="linkage_linker_private_weak">linker_private_weak</a></b></tt></dt>
556 <dd>Similar to "<tt>linker_private</tt>", but the symbol is weak. Note that
557 <tt>linker_private_weak</tt> symbols are subject to coalescing by the
558 linker. The symbols are removed by the linker from the final linked image
559 (executable or dynamic library).</dd>
Bill Wendling3d10a5a2009-07-20 01:03:30 +0000[diff] [blame]560
Bill Wendling55ae5152010-08-20 22:05:50 +0000[diff] [blame]561 <dt><tt><b><a name="linkage_linker_private_weak_def_auto">linker_private_weak_def_auto</a></b></tt></dt>
562 <dd>Similar to "<tt>linker_private_weak</tt>", but it's known that the address
563 of the object is not taken. For instance, functions that had an inline
564 definition, but the compiler decided not to inline it. Note,
565 unlike <tt>linker_private</tt> and <tt>linker_private_weak</tt>,
566 <tt>linker_private_weak_def_auto</tt> may have only <tt>default</tt>
567 visibility. The symbols are removed by the linker from the final linked
568 image (executable or dynamic library).</dd>
569
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]570 <dt><tt><b><a name="linkage_internal">internal</a></b></tt></dt>
Bill Wendling07d31772010-06-29 22:34:52 +0000[diff] [blame]571 <dd>Similar to private, but the value shows as a local symbol
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]572 (<tt>STB_LOCAL</tt> in the case of ELF) in the object file. This
573 corresponds to the notion of the '<tt>static</tt>' keyword in C.</dd>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]574
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]575 <dt><tt><b><a name="linkage_available_externally">available_externally</a></b></tt></dt>
Chris Lattner266c7bb2009-04-13 05:44:34 +0000[diff] [blame]576 <dd>Globals with "<tt>available_externally</tt>" linkage are never emitted
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]577 into the object file corresponding to the LLVM module. They exist to
578 allow inlining and other optimizations to take place given knowledge of
579 the definition of the global, which is known to be somewhere outside the
580 module. Globals with <tt>available_externally</tt> linkage are allowed to
581 be discarded at will, and are otherwise the same as <tt>linkonce_odr</tt>.
582 This linkage type is only allowed on definitions, not declarations.</dd>
Chris Lattner266c7bb2009-04-13 05:44:34 +0000[diff] [blame]583
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]584 <dt><tt><b><a name="linkage_linkonce">linkonce</a></b></tt></dt>
Chris Lattner4887bd82007-01-14 06:51:48 +0000[diff] [blame]585 <dd>Globals with "<tt>linkonce</tt>" linkage are merged with other globals of
Chris Lattner873187c2010-01-09 19:15:14 +0000[diff] [blame]586 the same name when linkage occurs. This can be used to implement
587 some forms of inline functions, templates, or other code which must be
588 generated in each translation unit that uses it, but where the body may
589 be overridden with a more definitive definition later. Unreferenced
590 <tt>linkonce</tt> globals are allowed to be discarded. Note that
591 <tt>linkonce</tt> linkage does not actually allow the optimizer to
592 inline the body of this function into callers because it doesn't know if
593 this definition of the function is the definitive definition within the
594 program or whether it will be overridden by a stronger definition.
595 To enable inlining and other optimizations, use "<tt>linkonce_odr</tt>"
596 linkage.</dd>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]597
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]598 <dt><tt><b><a name="linkage_weak">weak</a></b></tt></dt>
Chris Lattner26d054d2009-08-05 05:21:07 +0000[diff] [blame]599 <dd>"<tt>weak</tt>" linkage has the same merging semantics as
600 <tt>linkonce</tt> linkage, except that unreferenced globals with
601 <tt>weak</tt> linkage may not be discarded. This is used for globals that
602 are declared "weak" in C source code.</dd>
603
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]604 <dt><tt><b><a name="linkage_common">common</a></b></tt></dt>
Chris Lattner26d054d2009-08-05 05:21:07 +0000[diff] [blame]605 <dd>"<tt>common</tt>" linkage is most similar to "<tt>weak</tt>" linkage, but
606 they are used for tentative definitions in C, such as "<tt>int X;</tt>" at
607 global scope.
608 Symbols with "<tt>common</tt>" linkage are merged in the same way as
609 <tt>weak symbols</tt>, and they may not be deleted if unreferenced.
Chris Lattnercd81f5d2009-08-05 05:41:44 +0000[diff] [blame]610 <tt>common</tt> symbols may not have an explicit section,
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]611 must have a zero initializer, and may not be marked '<a
Chris Lattnercd81f5d2009-08-05 05:41:44 +0000[diff] [blame]612 href="#globalvars"><tt>constant</tt></a>'. Functions and aliases may not
613 have common linkage.</dd>
Chris Lattner26d054d2009-08-05 05:21:07 +0000[diff] [blame]614
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]615
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]616 <dt><tt><b><a name="linkage_appending">appending</a></b></tt></dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]617 <dd>"<tt>appending</tt>" linkage may only be applied to global variables of
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]618 pointer to array type. When two global variables with appending linkage
619 are linked together, the two global arrays are appended together. This is
620 the LLVM, typesafe, equivalent of having the system linker append together
621 "sections" with identical names when .o files are linked.</dd>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]622
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]623 <dt><tt><b><a name="linkage_externweak">extern_weak</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]624 <dd>The semantics of this linkage follow the ELF object file model: the symbol
625 is weak until linked, if not linked, the symbol becomes null instead of
626 being an undefined reference.</dd>
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]627
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]628 <dt><tt><b><a name="linkage_linkonce_odr">linkonce_odr</a></b></tt></dt>
629 <dt><tt><b><a name="linkage_weak_odr">weak_odr</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]630 <dd>Some languages allow differing globals to be merged, such as two functions
631 with different semantics. Other languages, such as <tt>C++</tt>, ensure
Bill Wendling5e721d72010-07-01 21:55:59 +0000[diff] [blame]632 that only equivalent globals are ever merged (the "one definition rule"
633 &mdash; "ODR"). Such languages can use the <tt>linkonce_odr</tt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]634 and <tt>weak_odr</tt> linkage types to indicate that the global will only
635 be merged with equivalent globals. These linkage types are otherwise the
636 same as their non-<tt>odr</tt> versions.</dd>
Duncan Sands667d4b82009-03-07 15:45:40 +0000[diff] [blame]637
Bill Wendlingf7f06102011-10-11 06:41:28 +0000[diff] [blame]638 <dt><tt><b><a name="linkage_external">external</a></b></tt>:</dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]639 <dd>If none of the above identifiers are used, the global is externally
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]640 visible, meaning that it participates in linkage and can be used to
641 resolve external symbol references.</dd>
Reid Spencerc8910842007-04-11 23:49:50 +0000[diff] [blame]642</dl>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]643
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]644<p>The next two types of linkage are targeted for Microsoft Windows platform
645 only. They are designed to support importing (exporting) symbols from (to)
646 DLLs (Dynamic Link Libraries).</p>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]647
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]648<dl>
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]649 <dt><tt><b><a name="linkage_dllimport">dllimport</a></b></tt></dt>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]650 <dd>"<tt>dllimport</tt>" linkage causes the compiler to reference a function
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]651 or variable via a global pointer to a pointer that is set up by the DLL
652 exporting the symbol. On Microsoft Windows targets, the pointer name is
653 formed by combining <code>__imp_</code> and the function or variable
654 name.</dd>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]655
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]656 <dt><tt><b><a name="linkage_dllexport">dllexport</a></b></tt></dt>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]657 <dd>"<tt>dllexport</tt>" linkage causes the compiler to provide a global
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]658 pointer to a pointer in a DLL, so that it can be referenced with the
659 <tt>dllimport</tt> attribute. On Microsoft Windows targets, the pointer
660 name is formed by combining <code>__imp_</code> and the function or
661 variable name.</dd>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]662</dl>
663
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]664<p>For example, since the "<tt>.LC0</tt>" variable is defined to be internal, if
665 another module defined a "<tt>.LC0</tt>" variable and was linked with this
666 one, one of the two would be renamed, preventing a collision. Since
667 "<tt>main</tt>" and "<tt>puts</tt>" are external (i.e., lacking any linkage
668 declarations), they are accessible outside of the current module.</p>
669
670<p>It is illegal for a function <i>declaration</i> to have any linkage type
Bill Wendlingf7f06102011-10-11 06:41:28 +0000[diff] [blame]671 other than <tt>external</tt>, <tt>dllimport</tt>
672 or <tt>extern_weak</tt>.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]673
Duncan Sands667d4b82009-03-07 15:45:40 +0000[diff] [blame]674<p>Aliases can have only <tt>external</tt>, <tt>internal</tt>, <tt>weak</tt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]675 or <tt>weak_odr</tt> linkages.</p>
676
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]677</div>
678
679<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]680<h3>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]681 <a name="callingconv">Calling Conventions</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]682</h3>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]683
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]684<div>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]685
686<p>LLVM <a href="#functionstructure">functions</a>, <a href="#i_call">calls</a>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]687 and <a href="#i_invoke">invokes</a> can all have an optional calling
688 convention specified for the call. The calling convention of any pair of
689 dynamic caller/callee must match, or the behavior of the program is
690 undefined. The following calling conventions are supported by LLVM, and more
691 may be added in the future:</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]692
693<dl>
694 <dt><b>"<tt>ccc</tt>" - The C calling convention</b>:</dt>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]695 <dd>This calling convention (the default if no other calling convention is
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]696 specified) matches the target C calling conventions. This calling
697 convention supports varargs function calls and tolerates some mismatch in
698 the declared prototype and implemented declaration of the function (as
699 does normal C).</dd>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]700
701 <dt><b>"<tt>fastcc</tt>" - The fast calling convention</b>:</dt>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]702 <dd>This calling convention attempts to make calls as fast as possible
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]703 (e.g. by passing things in registers). This calling convention allows the
704 target to use whatever tricks it wants to produce fast code for the
705 target, without having to conform to an externally specified ABI
Jeffrey Yasskin95fa80a2010-01-09 19:44:16 +0000[diff] [blame]706 (Application Binary Interface).
707 <a href="CodeGenerator.html#tailcallopt">Tail calls can only be optimized
Chris Lattner29689432010-03-11 00:22:57 +0000[diff] [blame]708 when this or the GHC convention is used.</a> This calling convention
709 does not support varargs and requires the prototype of all callees to
710 exactly match the prototype of the function definition.</dd>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]711
712 <dt><b>"<tt>coldcc</tt>" - The cold calling convention</b>:</dt>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]713 <dd>This calling convention attempts to make code in the caller as efficient
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]714 as possible under the assumption that the call is not commonly executed.
715 As such, these calls often preserve all registers so that the call does
716 not break any live ranges in the caller side. This calling convention
717 does not support varargs and requires the prototype of all callees to
718 exactly match the prototype of the function definition.</dd>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]719
Chris Lattner29689432010-03-11 00:22:57 +0000[diff] [blame]720 <dt><b>"<tt>cc <em>10</em></tt>" - GHC convention</b>:</dt>
721 <dd>This calling convention has been implemented specifically for use by the
722 <a href="http://www.haskell.org/ghc">Glasgow Haskell Compiler (GHC)</a>.
723 It passes everything in registers, going to extremes to achieve this by
724 disabling callee save registers. This calling convention should not be
725 used lightly but only for specific situations such as an alternative to
726 the <em>register pinning</em> performance technique often used when
727 implementing functional programming languages.At the moment only X86
728 supports this convention and it has the following limitations:
729 <ul>
730 <li>On <em>X86-32</em> only supports up to 4 bit type parameters. No
731 floating point types are supported.</li>
732 <li>On <em>X86-64</em> only supports up to 10 bit type parameters and
733 6 floating point parameters.</li>
734 </ul>
735 This calling convention supports
736 <a href="CodeGenerator.html#tailcallopt">tail call optimization</a> but
737 requires both the caller and callee are using it.
738 </dd>
739
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame]740 <dt><b>"<tt>cc &lt;<em>n</em>&gt;</tt>" - Numbered convention</b>:</dt>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]741 <dd>Any calling convention may be specified by number, allowing
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]742 target-specific calling conventions to be used. Target specific calling
743 conventions start at 64.</dd>
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame]744</dl>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]745
746<p>More calling conventions can be added/defined on an as-needed basis, to
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]747 support Pascal conventions or any other well-known target-independent
748 convention.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]749
750</div>
751
752<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]753<h3>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]754 <a name="visibility">Visibility Styles</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]755</h3>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]756
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]757<div>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]758
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]759<p>All Global Variables and Functions have one of the following visibility
760 styles:</p>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]761
762<dl>
763 <dt><b>"<tt>default</tt>" - Default style</b>:</dt>
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]764 <dd>On targets that use the ELF object file format, default visibility means
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]765 that the declaration is visible to other modules and, in shared libraries,
766 means that the declared entity may be overridden. On Darwin, default
767 visibility means that the declaration is visible to other modules. Default
768 visibility corresponds to "external linkage" in the language.</dd>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]769
770 <dt><b>"<tt>hidden</tt>" - Hidden style</b>:</dt>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]771 <dd>Two declarations of an object with hidden visibility refer to the same
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]772 object if they are in the same shared object. Usually, hidden visibility
773 indicates that the symbol will not be placed into the dynamic symbol
774 table, so no other module (executable or shared library) can reference it
775 directly.</dd>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]776
Anton Korobeynikov6f9896f2007-04-29 18:35:00 +0000[diff] [blame]777 <dt><b>"<tt>protected</tt>" - Protected style</b>:</dt>
Anton Korobeynikov6f9896f2007-04-29 18:35:00 +0000[diff] [blame]778 <dd>On ELF, protected visibility indicates that the symbol will be placed in
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]779 the dynamic symbol table, but that references within the defining module
780 will bind to the local symbol. That is, the symbol cannot be overridden by
781 another module.</dd>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]782</dl>
783
784</div>
785
786<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]787<h3>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]788 <a name="namedtypes">Named Types</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]789</h3>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]790
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]791<div>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]792
793<p>LLVM IR allows you to specify name aliases for certain types. This can make
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]794 it easier to read the IR and make the IR more condensed (particularly when
795 recursive types are involved). An example of a name specification is:</p>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]796
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]797<pre class="doc_code">
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]798%mytype = type { %mytype*, i32 }
799</pre>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]800
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]801<p>You may give a name to any <a href="#typesystem">type</a> except
Chris Lattnerdc65f222010-08-17 23:26:04 +0000[diff] [blame]802 "<a href="#t_void">void</a>". Type name aliases may be used anywhere a type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]803 is expected with the syntax "%mytype".</p>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]804
805<p>Note that type names are aliases for the structural type that they indicate,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]806 and that you can therefore specify multiple names for the same type. This
807 often leads to confusing behavior when dumping out a .ll file. Since LLVM IR
808 uses structural typing, the name is not part of the type. When printing out
809 LLVM IR, the printer will pick <em>one name</em> to render all types of a
810 particular shape. This means that if you have code where two different
811 source types end up having the same LLVM type, that the dumper will sometimes
812 print the "wrong" or unexpected type. This is an important design point and
813 isn't going to change.</p>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]814
815</div>
816
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]817<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]818<h3>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]819 <a name="globalvars">Global Variables</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]820</h3>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]821
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]822<div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]823
Chris Lattner3689a342005-02-12 19:30:21 +0000[diff] [blame]824<p>Global variables define regions of memory allocated at compilation time
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]825 instead of run-time. Global variables may optionally be initialized, may
826 have an explicit section to be placed in, and may have an optional explicit
827 alignment specified. A variable may be defined as "thread_local", which
828 means that it will not be shared by threads (each thread will have a
829 separated copy of the variable). A variable may be defined as a global
830 "constant," which indicates that the contents of the variable
831 will <b>never</b> be modified (enabling better optimization, allowing the
832 global data to be placed in the read-only section of an executable, etc).
833 Note that variables that need runtime initialization cannot be marked
834 "constant" as there is a store to the variable.</p>
Chris Lattner3689a342005-02-12 19:30:21 +0000[diff] [blame]835
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]836<p>LLVM explicitly allows <em>declarations</em> of global variables to be marked
837 constant, even if the final definition of the global is not. This capability
838 can be used to enable slightly better optimization of the program, but
839 requires the language definition to guarantee that optimizations based on the
840 'constantness' are valid for the translation units that do not include the
841 definition.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]842
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]843<p>As SSA values, global variables define pointer values that are in scope
844 (i.e. they dominate) all basic blocks in the program. Global variables
845 always define a pointer to their "content" type because they describe a
846 region of memory, and all memory objects in LLVM are accessed through
847 pointers.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]848
Rafael Espindolabea46262011-01-08 16:42:36 +0000[diff] [blame]849<p>Global variables can be marked with <tt>unnamed_addr</tt> which indicates
850 that the address is not significant, only the content. Constants marked
Rafael Espindolaa5eaa862011-01-15 08:20:57 +0000[diff] [blame]851 like this can be merged with other constants if they have the same
852 initializer. Note that a constant with significant address <em>can</em>
853 be merged with a <tt>unnamed_addr</tt> constant, the result being a
854 constant whose address is significant.</p>
Rafael Espindolabea46262011-01-08 16:42:36 +0000[diff] [blame]855
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]856<p>A global variable may be declared to reside in a target-specific numbered
857 address space. For targets that support them, address spaces may affect how
858 optimizations are performed and/or what target instructions are used to
859 access the variable. The default address space is zero. The address space
860 qualifier must precede any other attributes.</p>
Christopher Lamb284d9922007-12-11 09:31:00 +0000[diff] [blame]861
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]862<p>LLVM allows an explicit section to be specified for globals. If the target
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]863 supports it, it will emit globals to the section specified.</p>
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]864
Chris Lattnerce99fa92010-04-28 00:13:42 +0000[diff] [blame]865<p>An explicit alignment may be specified for a global, which must be a power
866 of 2. If not present, or if the alignment is set to zero, the alignment of
867 the global is set by the target to whatever it feels convenient. If an
868 explicit alignment is specified, the global is forced to have exactly that
Chris Lattner2d4b8ee2010-04-28 00:31:12 +0000[diff] [blame]869 alignment. Targets and optimizers are not allowed to over-align the global
870 if the global has an assigned section. In this case, the extra alignment
871 could be observable: for example, code could assume that the globals are
872 densely packed in their section and try to iterate over them as an array,
873 alignment padding would break this iteration.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]874
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]875<p>For example, the following defines a global in a numbered address space with
876 an initializer, section, and alignment:</p>
Chris Lattner68027ea2007-01-14 00:27:09 +0000[diff] [blame]877
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]878<pre class="doc_code">
Dan Gohman398873c2009-01-11 00:40:00 +0000[diff] [blame]879@G = addrspace(5) constant float 1.0, section "foo", align 4
Chris Lattner68027ea2007-01-14 00:27:09 +0000[diff] [blame]880</pre>
881
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]882</div>
883
884
885<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]886<h3>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]887 <a name="functionstructure">Functions</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]888</h3>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]889
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]890<div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]891
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]892<p>LLVM function definitions consist of the "<tt>define</tt>" keyword, an
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]893 optional <a href="#linkage">linkage type</a>, an optional
894 <a href="#visibility">visibility style</a>, an optional
Rafael Espindolabea46262011-01-08 16:42:36 +0000[diff] [blame]895 <a href="#callingconv">calling convention</a>,
896 an optional <tt>unnamed_addr</tt> attribute, a return type, an optional
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]897 <a href="#paramattrs">parameter attribute</a> for the return type, a function
898 name, a (possibly empty) argument list (each with optional
899 <a href="#paramattrs">parameter attributes</a>), optional
900 <a href="#fnattrs">function attributes</a>, an optional section, an optional
901 alignment, an optional <a href="#gc">garbage collector name</a>, an opening
902 curly brace, a list of basic blocks, and a closing curly brace.</p>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]903
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]904<p>LLVM function declarations consist of the "<tt>declare</tt>" keyword, an
905 optional <a href="#linkage">linkage type</a>, an optional
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]906 <a href="#visibility">visibility style</a>, an optional
Rafael Espindolabea46262011-01-08 16:42:36 +0000[diff] [blame]907 <a href="#callingconv">calling convention</a>,
908 an optional <tt>unnamed_addr</tt> attribute, a return type, an optional
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]909 <a href="#paramattrs">parameter attribute</a> for the return type, a function
910 name, a possibly empty list of arguments, an optional alignment, and an
911 optional <a href="#gc">garbage collector name</a>.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]912
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]913<p>A function definition contains a list of basic blocks, forming the CFG
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]914 (Control Flow Graph) for the function. Each basic block may optionally start
915 with a label (giving the basic block a symbol table entry), contains a list
916 of instructions, and ends with a <a href="#terminators">terminator</a>
917 instruction (such as a branch or function return).</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]918
Chris Lattner4a3c9012007-06-08 16:52:14 +0000[diff] [blame]919<p>The first basic block in a function is special in two ways: it is immediately
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]920 executed on entrance to the function, and it is not allowed to have
921 predecessor basic blocks (i.e. there can not be any branches to the entry
922 block of a function). Because the block can have no predecessors, it also
923 cannot have any <a href="#i_phi">PHI nodes</a>.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]924
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]925<p>LLVM allows an explicit section to be specified for functions. If the target
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]926 supports it, it will emit functions to the section specified.</p>
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]927
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]928<p>An explicit alignment may be specified for a function. If not present, or if
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]929 the alignment is set to zero, the alignment of the function is set by the
930 target to whatever it feels convenient. If an explicit alignment is
931 specified, the function is forced to have at least that much alignment. All
932 alignments must be a power of 2.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]933
Rafael Espindolabea46262011-01-08 16:42:36 +0000[diff] [blame]934<p>If the <tt>unnamed_addr</tt> attribute is given, the address is know to not
935 be significant and two identical functions can be merged</p>.
936
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]937<h5>Syntax:</h5>
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]938<pre class="doc_code">
Chris Lattner50ad45c2008-10-13 16:55:18 +0000[diff] [blame]939define [<a href="#linkage">linkage</a>] [<a href="#visibility">visibility</a>]
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]940 [<a href="#callingconv">cconv</a>] [<a href="#paramattrs">ret attrs</a>]
941 &lt;ResultType&gt; @&lt;FunctionName&gt; ([argument list])
942 [<a href="#fnattrs">fn Attrs</a>] [section "name"] [align N]
943 [<a href="#gc">gc</a>] { ... }
944</pre>
Devang Patel307e8ab2008-10-07 17:48:33 +0000[diff] [blame]945
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]946</div>
947
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]948<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]949<h3>
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]950 <a name="aliasstructure">Aliases</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]951</h3>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]952
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]953<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]954
955<p>Aliases act as "second name" for the aliasee value (which can be either
956 function, global variable, another alias or bitcast of global value). Aliases
957 may have an optional <a href="#linkage">linkage type</a>, and an
958 optional <a href="#visibility">visibility style</a>.</p>
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]959
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]960<h5>Syntax:</h5>
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]961<pre class="doc_code">
Duncan Sands0b23ac12008-09-12 20:48:21 +0000[diff] [blame]962@&lt;Name&gt; = alias [Linkage] [Visibility] &lt;AliaseeTy&gt; @&lt;Aliasee&gt;
Bill Wendlingaac388b2007-05-29 09:42:13 +0000[diff] [blame]963</pre>
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]964
965</div>
966
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]967<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]968<h3>
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]969 <a name="namedmetadatastructure">Named Metadata</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]970</h3>
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]971
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]972<div>
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]973
Chris Lattnere6a5ddd2010-01-15 21:50:19 +0000[diff] [blame]974<p>Named metadata is a collection of metadata. <a href="#metadata">Metadata
Dan Gohman872814a2010-07-21 18:54:18 +0000[diff] [blame]975 nodes</a> (but not metadata strings) are the only valid operands for
Chris Lattnere6a5ddd2010-01-15 21:50:19 +0000[diff] [blame]976 a named metadata.</p>
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]977
978<h5>Syntax:</h5>
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]979<pre class="doc_code">
Dan Gohman872814a2010-07-21 18:54:18 +0000[diff] [blame]980; Some unnamed metadata nodes, which are referenced by the named metadata.
981!0 = metadata !{metadata !"zero"}
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]982!1 = metadata !{metadata !"one"}
Dan Gohman872814a2010-07-21 18:54:18 +0000[diff] [blame]983!2 = metadata !{metadata !"two"}
Dan Gohman1005bc52010-07-13 19:48:13 +0000[diff] [blame]984; A named metadata.
Dan Gohman872814a2010-07-21 18:54:18 +0000[diff] [blame]985!name = !{!0, !1, !2}
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]986</pre>
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]987
988</div>
989
990<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]991<h3>
992 <a name="paramattrs">Parameter Attributes</a>
993</h3>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]994
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]995<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]996
997<p>The return type and each parameter of a function type may have a set of
998 <i>parameter attributes</i> associated with them. Parameter attributes are
999 used to communicate additional information about the result or parameters of
1000 a function. Parameter attributes are considered to be part of the function,
1001 not of the function type, so functions with different parameter attributes
1002 can have the same function type.</p>
1003
1004<p>Parameter attributes are simple keywords that follow the type specified. If
1005 multiple parameter attributes are needed, they are space separated. For
1006 example:</p>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1007
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]1008<pre class="doc_code">
Nick Lewyckyb6a7d252009-02-15 23:06:14 +0000[diff] [blame]1009declare i32 @printf(i8* noalias nocapture, ...)
Chris Lattner66d922c2008-10-04 18:33:34 +0000[diff] [blame]1010declare i32 @atoi(i8 zeroext)
1011declare signext i8 @returns_signed_char()
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1012</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1013
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1014<p>Note that any attributes for the function result (<tt>nounwind</tt>,
1015 <tt>readonly</tt>) come immediately after the argument list.</p>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1016
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1017<p>Currently, only the following parameter attributes are defined:</p>
Chris Lattner47507de2008-01-11 06:20:47 +0000[diff] [blame]1018
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1019<dl>
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1020 <dt><tt><b>zeroext</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1021 <dd>This indicates to the code generator that the parameter or return value
Cameron Zwarichebe81732011-03-16 22:20:18 +0000[diff] [blame]1022 should be zero-extended to the extent required by the target's ABI (which
1023 is usually 32-bits, but is 8-bits for a i1 on x86-64) by the caller (for a
1024 parameter) or the callee (for a return value).</dd>
Chris Lattner47507de2008-01-11 06:20:47 +0000[diff] [blame]1025
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1026 <dt><tt><b>signext</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1027 <dd>This indicates to the code generator that the parameter or return value
Cameron Zwarich9e69ff92011-03-17 14:21:58 +0000[diff] [blame]1028 should be sign-extended to the extent required by the target's ABI (which
1029 is usually 32-bits) by the caller (for a parameter) or the callee (for a
1030 return value).</dd>
Chris Lattner47507de2008-01-11 06:20:47 +0000[diff] [blame]1031
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1032 <dt><tt><b>inreg</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1033 <dd>This indicates that this parameter or return value should be treated in a
1034 special target-dependent fashion during while emitting code for a function
1035 call or return (usually, by putting it in a register as opposed to memory,
1036 though some targets use it to distinguish between two different kinds of
1037 registers). Use of this attribute is target-specific.</dd>
Chris Lattner47507de2008-01-11 06:20:47 +0000[diff] [blame]1038
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1039 <dt><tt><b><a name="byval">byval</a></b></tt></dt>
Chris Lattnera6fd81d2010-11-20 23:49:06 +0000[diff] [blame]1040 <dd><p>This indicates that the pointer parameter should really be passed by
1041 value to the function. The attribute implies that a hidden copy of the
1042 pointee
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1043 is made between the caller and the callee, so the callee is unable to
1044 modify the value in the callee. This attribute is only valid on LLVM
1045 pointer arguments. It is generally used to pass structs and arrays by
1046 value, but is also valid on pointers to scalars. The copy is considered
1047 to belong to the caller not the callee (for example,
1048 <tt><a href="#readonly">readonly</a></tt> functions should not write to
1049 <tt>byval</tt> parameters). This is not a valid attribute for return
Chris Lattnera6fd81d2010-11-20 23:49:06 +0000[diff] [blame]1050 values.</p>
1051
1052 <p>The byval attribute also supports specifying an alignment with
1053 the align attribute. It indicates the alignment of the stack slot to
1054 form and the known alignment of the pointer specified to the call site. If
1055 the alignment is not specified, then the code generator makes a
1056 target-specific assumption.</p></dd>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1057
Dan Gohmanff235352010-07-02 23:18:08 +0000[diff] [blame]1058 <dt><tt><b><a name="sret">sret</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1059 <dd>This indicates that the pointer parameter specifies the address of a
1060 structure that is the return value of the function in the source program.
1061 This pointer must be guaranteed by the caller to be valid: loads and
1062 stores to the structure may be assumed by the callee to not to trap. This
1063 may only be applied to the first parameter. This is not a valid attribute
1064 for return values. </dd>
1065
Dan Gohmanff235352010-07-02 23:18:08 +0000[diff] [blame]1066 <dt><tt><b><a name="noalias">noalias</a></b></tt></dt>
Dan Gohman1e109622010-07-02 18:41:32 +0000[diff] [blame]1067 <dd>This indicates that pointer values
1068 <a href="#pointeraliasing"><i>based</i></a> on the argument or return
Dan Gohmanefca7f92010-07-02 23:46:54 +0000[diff] [blame]1069 value do not alias pointer values which are not <i>based</i> on it,
1070 ignoring certain "irrelevant" dependencies.
1071 For a call to the parent function, dependencies between memory
1072 references from before or after the call and from those during the call
1073 are "irrelevant" to the <tt>noalias</tt> keyword for the arguments and
1074 return value used in that call.
Dan Gohman1e109622010-07-02 18:41:32 +0000[diff] [blame]1075 The caller shares the responsibility with the callee for ensuring that
1076 these requirements are met.
1077 For further details, please see the discussion of the NoAlias response in
Dan Gohmanff70fe42010-07-06 15:26:33 +0000[diff] [blame]1078 <a href="AliasAnalysis.html#MustMayNo">alias analysis</a>.<br>
1079<br>
John McCall191d4ee2010-07-06 21:07:14 +0000[diff] [blame]1080 Note that this definition of <tt>noalias</tt> is intentionally
1081 similar to the definition of <tt>restrict</tt> in C99 for function
Chris Lattner211244a2010-07-06 20:51:35 +0000[diff] [blame]1082 arguments, though it is slightly weaker.
Dan Gohmanff70fe42010-07-06 15:26:33 +0000[diff] [blame]1083<br>
1084 For function return values, C99's <tt>restrict</tt> is not meaningful,
1085 while LLVM's <tt>noalias</tt> is.
1086 </dd>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1087
Dan Gohmanff235352010-07-02 23:18:08 +0000[diff] [blame]1088 <dt><tt><b><a name="nocapture">nocapture</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1089 <dd>This indicates that the callee does not make any copies of the pointer
1090 that outlive the callee itself. This is not a valid attribute for return
1091 values.</dd>
1092
Dan Gohmanff235352010-07-02 23:18:08 +0000[diff] [blame]1093 <dt><tt><b><a name="nest">nest</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1094 <dd>This indicates that the pointer parameter can be excised using the
1095 <a href="#int_trampoline">trampoline intrinsics</a>. This is not a valid
1096 attribute for return values.</dd>
1097</dl>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1098
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1099</div>
1100
1101<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1102<h3>
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]1103 <a name="gc">Garbage Collector Names</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1104</h3>
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]1105
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1106<div>
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]1107
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1108<p>Each function may specify a garbage collector name, which is simply a
1109 string:</p>
1110
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]1111<pre class="doc_code">
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1112define void @f() gc "name" { ... }
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1113</pre>
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]1114
1115<p>The compiler declares the supported values of <i>name</i>. Specifying a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1116 collector which will cause the compiler to alter its output in order to
1117 support the named garbage collection algorithm.</p>
1118
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]1119</div>
1120
1121<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1122<h3>
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1123 <a name="fnattrs">Function Attributes</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1124</h3>
Devang Patelf8b94812008-09-04 23:05:13 +0000[diff] [blame]1125
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1126<div>
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1127
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1128<p>Function attributes are set to communicate additional information about a
1129 function. Function attributes are considered to be part of the function, not
1130 of the function type, so functions with different parameter attributes can
1131 have the same function type.</p>
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1132
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1133<p>Function attributes are simple keywords that follow the type specified. If
1134 multiple attributes are needed, they are space separated. For example:</p>
Devang Patelf8b94812008-09-04 23:05:13 +0000[diff] [blame]1135
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]1136<pre class="doc_code">
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1137define void @f() noinline { ... }
1138define void @f() alwaysinline { ... }
1139define void @f() alwaysinline optsize { ... }
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1140define void @f() optsize { ... }
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1141</pre>
Devang Patelf8b94812008-09-04 23:05:13 +0000[diff] [blame]1142
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1143<dl>
Charles Davis1e063d12010-02-12 00:31:15 +0000[diff] [blame]1144 <dt><tt><b>alignstack(&lt;<em>n</em>&gt;)</b></tt></dt>
1145 <dd>This attribute indicates that, when emitting the prologue and epilogue,
1146 the backend should forcibly align the stack pointer. Specify the
1147 desired alignment, which must be a power of two, in parentheses.
1148
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1149 <dt><tt><b>alwaysinline</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1150 <dd>This attribute indicates that the inliner should attempt to inline this
1151 function into callers whenever possible, ignoring any active inlining size
1152 threshold for this caller.</dd>
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1153
Dan Gohman129bd562011-06-16 16:03:13 +0000[diff] [blame]1154 <dt><tt><b>nonlazybind</b></tt></dt>
1155 <dd>This attribute suppresses lazy symbol binding for the function. This
1156 may make calls to the function faster, at the cost of extra program
1157 startup time if the function is not called during program startup.</dd>
1158
Jakob Stoklund Olesen570a4a52010-02-06 01:16:28 +0000[diff] [blame]1159 <dt><tt><b>inlinehint</b></tt></dt>
1160 <dd>This attribute indicates that the source code contained a hint that inlining
1161 this function is desirable (such as the "inline" keyword in C/C++). It
1162 is just a hint; it imposes no requirements on the inliner.</dd>
1163
Nick Lewycky76ec37a2010-07-06 18:24:09 +0000[diff] [blame]1164 <dt><tt><b>naked</b></tt></dt>
1165 <dd>This attribute disables prologue / epilogue emission for the function.
1166 This can have very system-specific consequences.</dd>
1167
1168 <dt><tt><b>noimplicitfloat</b></tt></dt>
1169 <dd>This attributes disables implicit floating point instructions.</dd>
1170
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1171 <dt><tt><b>noinline</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1172 <dd>This attribute indicates that the inliner should never inline this
1173 function in any situation. This attribute may not be used together with
1174 the <tt>alwaysinline</tt> attribute.</dd>
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1175
Nick Lewycky76ec37a2010-07-06 18:24:09 +0000[diff] [blame]1176 <dt><tt><b>noredzone</b></tt></dt>
1177 <dd>This attribute indicates that the code generator should not use a red
1178 zone, even if the target-specific ABI normally permits it.</dd>
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1179
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1180 <dt><tt><b>noreturn</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1181 <dd>This function attribute indicates that the function never returns
1182 normally. This produces undefined behavior at runtime if the function
1183 ever does dynamically return.</dd>
Bill Wendling31359ba2008-11-13 01:02:51 +0000[diff] [blame]1184
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1185 <dt><tt><b>nounwind</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1186 <dd>This function attribute indicates that the function never returns with an
1187 unwind or exceptional control flow. If the function does unwind, its
1188 runtime behavior is undefined.</dd>
Bill Wendlingfbaa7ed2008-11-26 19:07:40 +0000[diff] [blame]1189
Nick Lewycky76ec37a2010-07-06 18:24:09 +0000[diff] [blame]1190 <dt><tt><b>optsize</b></tt></dt>
1191 <dd>This attribute suggests that optimization passes and code generator passes
1192 make choices that keep the code size of this function low, and otherwise
1193 do optimizations specifically to reduce code size.</dd>
1194
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1195 <dt><tt><b>readnone</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1196 <dd>This attribute indicates that the function computes its result (or decides
1197 to unwind an exception) based strictly on its arguments, without
1198 dereferencing any pointer arguments or otherwise accessing any mutable
1199 state (e.g. memory, control registers, etc) visible to caller functions.
1200 It does not write through any pointer arguments
1201 (including <tt><a href="#byval">byval</a></tt> arguments) and never
1202 changes any state visible to callers. This means that it cannot unwind
1203 exceptions by calling the <tt>C++</tt> exception throwing methods, but
1204 could use the <tt>unwind</tt> instruction.</dd>
Devang Patel5d96fda2009-06-12 19:45:19 +0000[diff] [blame]1205
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1206 <dt><tt><b><a name="readonly">readonly</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1207 <dd>This attribute indicates that the function does not write through any
1208 pointer arguments (including <tt><a href="#byval">byval</a></tt>
1209 arguments) or otherwise modify any state (e.g. memory, control registers,
1210 etc) visible to caller functions. It may dereference pointer arguments
1211 and read state that may be set in the caller. A readonly function always
1212 returns the same value (or unwinds an exception identically) when called
1213 with the same set of arguments and global state. It cannot unwind an
1214 exception by calling the <tt>C++</tt> exception throwing methods, but may
1215 use the <tt>unwind</tt> instruction.</dd>
Anton Korobeynikovc5ec8a72009-07-17 18:07:26 +0000[diff] [blame]1216
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1217 <dt><tt><b><a name="ssp">ssp</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1218 <dd>This attribute indicates that the function should emit a stack smashing
1219 protector. It is in the form of a "canary"&mdash;a random value placed on
1220 the stack before the local variables that's checked upon return from the
1221 function to see if it has been overwritten. A heuristic is used to
1222 determine if a function needs stack protectors or not.<br>
1223<br>
1224 If a function that has an <tt>ssp</tt> attribute is inlined into a
1225 function that doesn't have an <tt>ssp</tt> attribute, then the resulting
1226 function will have an <tt>ssp</tt> attribute.</dd>
1227
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1228 <dt><tt><b>sspreq</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1229 <dd>This attribute indicates that the function should <em>always</em> emit a
1230 stack smashing protector. This overrides
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1231 the <tt><a href="#ssp">ssp</a></tt> function attribute.<br>
1232<br>
1233 If a function that has an <tt>sspreq</tt> attribute is inlined into a
1234 function that doesn't have an <tt>sspreq</tt> attribute or which has
1235 an <tt>ssp</tt> attribute, then the resulting function will have
1236 an <tt>sspreq</tt> attribute.</dd>
Rafael Espindolafbff0ec2011-07-25 15:27:59 +0000[diff] [blame]1237
1238 <dt><tt><b><a name="uwtable">uwtable</a></b></tt></dt>
1239 <dd>This attribute indicates that the ABI being targeted requires that
1240 an unwind table entry be produce for this function even if we can
1241 show that no exceptions passes by it. This is normally the case for
1242 the ELF x86-64 abi, but it can be disabled for some compilation
1243 units.</dd>
1244
Rafael Espindola25456ef2011-10-03 14:45:37 +0000[diff] [blame]1245 <dt><tt><b><a name="returns_twice">returns_twice</a></b></tt></dt>
1246 <dd>This attribute indicates that this function can return
1247 twice. The C <code>setjmp</code> is an example of such a function.
1248 The compiler disables some optimizations (like tail calls) in the caller of
1249 these functions.</dd>
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1250</dl>
1251
Devang Patelf8b94812008-09-04 23:05:13 +0000[diff] [blame]1252</div>
1253
1254<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1255<h3>
Chris Lattner1eeeb0c2006-04-08 04:40:53 +0000[diff] [blame]1256 <a name="moduleasm">Module-Level Inline Assembly</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1257</h3>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1258
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1259<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1260
1261<p>Modules may contain "module-level inline asm" blocks, which corresponds to
1262 the GCC "file scope inline asm" blocks. These blocks are internally
1263 concatenated by LLVM and treated as a single unit, but may be separated in
1264 the <tt>.ll</tt> file if desired. The syntax is very simple:</p>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1265
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]1266<pre class="doc_code">
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1267module asm "inline asm code goes here"
1268module asm "more can go here"
1269</pre>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1270
1271<p>The strings can contain any character by escaping non-printable characters.
1272 The escape sequence used is simply "\xx" where "xx" is the two digit hex code
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1273 for the number.</p>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1274
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1275<p>The inline asm code is simply printed to the machine code .s file when
1276 assembly code is generated.</p>
1277
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1278</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1279
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1280<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1281<h3>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1282 <a name="datalayout">Data Layout</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1283</h3>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1284
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1285<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1286
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1287<p>A module may specify a target specific data layout string that specifies how
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1288 data is to be laid out in memory. The syntax for the data layout is
1289 simply:</p>
1290
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]1291<pre class="doc_code">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1292target datalayout = "<i>layout specification</i>"
1293</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1294
1295<p>The <i>layout specification</i> consists of a list of specifications
1296 separated by the minus sign character ('-'). Each specification starts with
1297 a letter and may include other information after the letter to define some
1298 aspect of the data layout. The specifications accepted are as follows:</p>
1299
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1300<dl>
1301 <dt><tt>E</tt></dt>
1302 <dd>Specifies that the target lays out data in big-endian form. That is, the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1303 bits with the most significance have the lowest address location.</dd>
1304
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1305 <dt><tt>e</tt></dt>
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]1306 <dd>Specifies that the target lays out data in little-endian form. That is,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1307 the bits with the least significance have the lowest address
1308 location.</dd>
1309
Lang Hamesbb5b3f32011-10-10 23:42:08 +0000[diff] [blame]1310 <dt><tt>S<i>size</i></tt></dt>
1311 <dd>Specifies the natural alignment of the stack in bits. Alignment promotion
1312 of stack variables is limited to the natural stack alignment to avoid
1313 dynamic stack realignment. The stack alignment must be a multiple of
Lang Hames5f119a62011-10-11 17:50:14 +0000[diff] [blame]1314 8-bits. If omitted, the natural stack alignment defaults to "unspecified",
1315 which does not prevent any alignment promotions.</dd>
Lang Hamesbb5b3f32011-10-10 23:42:08 +0000[diff] [blame]1316
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1317 <dt><tt>p:<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]1318 <dd>This specifies the <i>size</i> of a pointer and its <i>abi</i> and
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1319 <i>preferred</i> alignments. All sizes are in bits. Specifying
1320 the <i>pref</i> alignment is optional. If omitted, the
1321 preceding <tt>:</tt> should be omitted too.</dd>
1322
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1323 <dt><tt>i<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1324 <dd>This specifies the alignment for an integer type of a given bit
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1325 <i>size</i>. The value of <i>size</i> must be in the range [1,2^23).</dd>
1326
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1327 <dt><tt>v<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]1328 <dd>This specifies the alignment for a vector type of a given bit
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1329 <i>size</i>.</dd>
1330
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1331 <dt><tt>f<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]1332 <dd>This specifies the alignment for a floating point type of a given bit
Dale Johannesen9d8d2212010-05-28 18:54:47 +0000[diff] [blame]1333 <i>size</i>. Only values of <i>size</i> that are supported by the target
1334 will work. 32 (float) and 64 (double) are supported on all targets;
1335 80 or 128 (different flavors of long double) are also supported on some
1336 targets.
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1337
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1338 <dt><tt>a<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1339 <dd>This specifies the alignment for an aggregate type of a given bit
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1340 <i>size</i>.</dd>
1341
Daniel Dunbar87bde0b2009-06-08 22:17:53 +0000[diff] [blame]1342 <dt><tt>s<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1343 <dd>This specifies the alignment for a stack object of a given bit
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1344 <i>size</i>.</dd>
Chris Lattnere82bdc42009-11-07 09:35:34 +0000[diff] [blame]1345
1346 <dt><tt>n<i>size1</i>:<i>size2</i>:<i>size3</i>...</tt></dt>
1347 <dd>This specifies a set of native integer widths for the target CPU
1348 in bits. For example, it might contain "n32" for 32-bit PowerPC,
1349 "n32:64" for PowerPC 64, or "n8:16:32:64" for X86-64. Elements of
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]1350 this set are considered to support most general arithmetic
Chris Lattnere82bdc42009-11-07 09:35:34 +0000[diff] [blame]1351 operations efficiently.</dd>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1352</dl>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1353
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1354<p>When constructing the data layout for a given target, LLVM starts with a
Dan Gohman1c70c002010-04-28 00:36:01 +0000[diff] [blame]1355 default set of specifications which are then (possibly) overridden by the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1356 specifications in the <tt>datalayout</tt> keyword. The default specifications
1357 are given in this list:</p>
1358
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1359<ul>
1360 <li><tt>E</tt> - big endian</li>
Dan Gohmanfdf2e8c2010-02-23 02:44:03 +0000[diff] [blame]1361 <li><tt>p:64:64:64</tt> - 64-bit pointers with 64-bit alignment</li>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1362 <li><tt>i1:8:8</tt> - i1 is 8-bit (byte) aligned</li>
1363 <li><tt>i8:8:8</tt> - i8 is 8-bit (byte) aligned</li>
1364 <li><tt>i16:16:16</tt> - i16 is 16-bit aligned</li>
1365 <li><tt>i32:32:32</tt> - i32 is 32-bit aligned</li>
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]1366 <li><tt>i64:32:64</tt> - i64 has ABI alignment of 32-bits but preferred
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1367 alignment of 64-bits</li>
1368 <li><tt>f32:32:32</tt> - float is 32-bit aligned</li>
1369 <li><tt>f64:64:64</tt> - double is 64-bit aligned</li>
1370 <li><tt>v64:64:64</tt> - 64-bit vector is 64-bit aligned</li>
1371 <li><tt>v128:128:128</tt> - 128-bit vector is 128-bit aligned</li>
1372 <li><tt>a0:0:1</tt> - aggregates are 8-bit aligned</li>
Daniel Dunbar87bde0b2009-06-08 22:17:53 +0000[diff] [blame]1373 <li><tt>s0:64:64</tt> - stack objects are 64-bit aligned</li>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1374</ul>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1375
1376<p>When LLVM is determining the alignment for a given type, it uses the
1377 following rules:</p>
1378
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1379<ol>
1380 <li>If the type sought is an exact match for one of the specifications, that
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1381 specification is used.</li>
1382
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1383 <li>If no match is found, and the type sought is an integer type, then the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1384 smallest integer type that is larger than the bitwidth of the sought type
1385 is used. If none of the specifications are larger than the bitwidth then
1386 the the largest integer type is used. For example, given the default
1387 specifications above, the i7 type will use the alignment of i8 (next
1388 largest) while both i65 and i256 will use the alignment of i64 (largest
1389 specified).</li>
1390
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1391 <li>If no match is found, and the type sought is a vector type, then the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1392 largest vector type that is smaller than the sought vector type will be
1393 used as a fall back. This happens because &lt;128 x double&gt; can be
1394 implemented in terms of 64 &lt;2 x double&gt;, for example.</li>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1395</ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1396
Chris Lattner6509f502011-10-11 23:01:39 +0000[diff] [blame]1397<p>The function of the data layout string may not be what you expect. Notably,
1398 this is not a specification from the frontend of what alignment the code
1399 generator should use.</p>
1400
1401<p>Instead, if specified, the target data layout is required to match what the
1402 ultimate <em>code generator</em> expects. This string is used by the
1403 mid-level optimizers to
1404 improve code, and this only works if it matches what the ultimate code
1405 generator uses. If you would like to generate IR that does not embed this
1406 target-specific detail into the IR, then you don't have to specify the
1407 string. This will disable some optimizations that require precise layout
1408 information, but this also prevents those optimizations from introducing
1409 target specificity into the IR.</p>
1410
1411
1412
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1413</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1414
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1415<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1416<h3>
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1417 <a name="pointeraliasing">Pointer Aliasing Rules</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1418</h3>
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1419
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1420<div>
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1421
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1422<p>Any memory access must be done through a pointer value associated
Andreas Bolka99a82052009-07-27 20:37:10 +0000[diff] [blame]1423with an address range of the memory access, otherwise the behavior
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1424is undefined. Pointer values are associated with address ranges
1425according to the following rules:</p>
1426
1427<ul>
Dan Gohman1e109622010-07-02 18:41:32 +0000[diff] [blame]1428 <li>A pointer value is associated with the addresses associated with
1429 any value it is <i>based</i> on.
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1430 <li>An address of a global variable is associated with the address
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1431 range of the variable's storage.</li>
1432 <li>The result value of an allocation instruction is associated with
1433 the address range of the allocated storage.</li>
1434 <li>A null pointer in the default address-space is associated with
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1435 no address.</li>
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1436 <li>An integer constant other than zero or a pointer value returned
1437 from a function not defined within LLVM may be associated with address
1438 ranges allocated through mechanisms other than those provided by
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1439 LLVM. Such ranges shall not overlap with any ranges of addresses
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1440 allocated by mechanisms provided by LLVM.</li>
Dan Gohman1e109622010-07-02 18:41:32 +0000[diff] [blame]1441</ul>
1442
1443<p>A pointer value is <i>based</i> on another pointer value according
1444 to the following rules:</p>
1445
1446<ul>
1447 <li>A pointer value formed from a
1448 <tt><a href="#i_getelementptr">getelementptr</a></tt> operation
1449 is <i>based</i> on the first operand of the <tt>getelementptr</tt>.</li>
1450 <li>The result value of a
1451 <tt><a href="#i_bitcast">bitcast</a></tt> is <i>based</i> on the operand
1452 of the <tt>bitcast</tt>.</li>
1453 <li>A pointer value formed by an
1454 <tt><a href="#i_inttoptr">inttoptr</a></tt> is <i>based</i> on all
1455 pointer values that contribute (directly or indirectly) to the
1456 computation of the pointer's value.</li>
1457 <li>The "<i>based</i> on" relationship is transitive.</li>
1458</ul>
1459
1460<p>Note that this definition of <i>"based"</i> is intentionally
1461 similar to the definition of <i>"based"</i> in C99, though it is
1462 slightly weaker.</p>
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1463
1464<p>LLVM IR does not associate types with memory. The result type of a
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1465<tt><a href="#i_load">load</a></tt> merely indicates the size and
1466alignment of the memory from which to load, as well as the
Dan Gohmanc22c0f32010-06-17 19:23:50 +0000[diff] [blame]1467interpretation of the value. The first operand type of a
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1468<tt><a href="#i_store">store</a></tt> similarly only indicates the size
1469and alignment of the store.</p>
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1470
1471<p>Consequently, type-based alias analysis, aka TBAA, aka
1472<tt>-fstrict-aliasing</tt>, is not applicable to general unadorned
1473LLVM IR. <a href="#metadata">Metadata</a> may be used to encode
1474additional information which specialized optimization passes may use
1475to implement type-based alias analysis.</p>
1476
1477</div>
1478
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]1479<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1480<h3>
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]1481 <a name="volatile">Volatile Memory Accesses</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1482</h3>
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]1483
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1484<div>
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]1485
1486<p>Certain memory accesses, such as <a href="#i_load"><tt>load</tt></a>s, <a
1487href="#i_store"><tt>store</tt></a>s, and <a
1488href="#int_memcpy"><tt>llvm.memcpy</tt></a>s may be marked <tt>volatile</tt>.
1489The optimizers must not change the number of volatile operations or change their
1490order of execution relative to other volatile operations. The optimizers
1491<i>may</i> change the order of volatile operations relative to non-volatile
1492operations. This is not Java's "volatile" and has no cross-thread
1493synchronization behavior.</p>
1494
1495</div>
1496
Eli Friedman5b60e1b2011-07-20 21:35:53 +0000[diff] [blame]1497<!-- ======================================================================= -->
1498<h3>
1499 <a name="memmodel">Memory Model for Concurrent Operations</a>
1500</h3>
1501
1502<div>
1503
1504<p>The LLVM IR does not define any way to start parallel threads of execution
1505or to register signal handlers. Nonetheless, there are platform-specific
1506ways to create them, and we define LLVM IR's behavior in their presence. This
1507model is inspired by the C++0x memory model.</p>
1508
Eli Friedman234bccd2011-08-22 21:35:27 +0000[diff] [blame]1509<p>For a more informal introduction to this model, see the
1510<a href="Atomics.html">LLVM Atomic Instructions and Concurrency Guide</a>.
1511
Eli Friedman5b60e1b2011-07-20 21:35:53 +0000[diff] [blame]1512<p>We define a <i>happens-before</i> partial order as the least partial order
1513that</p>
1514<ul>
1515 <li>Is a superset of single-thread program order, and</li>
1516 <li>When a <i>synchronizes-with</i> <tt>b</tt>, includes an edge from
1517 <tt>a</tt> to <tt>b</tt>. <i>Synchronizes-with</i> pairs are introduced
1518 by platform-specific techniques, like pthread locks, thread
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1519 creation, thread joining, etc., and by atomic instructions.
1520 (See also <a href="#ordering">Atomic Memory Ordering Constraints</a>).
1521 </li>
Eli Friedman5b60e1b2011-07-20 21:35:53 +0000[diff] [blame]1522</ul>
1523
1524<p>Note that program order does not introduce <i>happens-before</i> edges
1525between a thread and signals executing inside that thread.</p>
1526
1527<p>Every (defined) read operation (load instructions, memcpy, atomic
1528loads/read-modify-writes, etc.) <var>R</var> reads a series of bytes written by
1529(defined) write operations (store instructions, atomic
Eli Friedman118973a2011-07-22 03:04:45 +0000[diff] [blame]1530stores/read-modify-writes, memcpy, etc.). For the purposes of this section,
1531initialized globals are considered to have a write of the initializer which is
1532atomic and happens before any other read or write of the memory in question.
1533For each byte of a read <var>R</var>, <var>R<sub>byte</sub></var> may see
1534any write to the same byte, except:</p>
Eli Friedman5b60e1b2011-07-20 21:35:53 +0000[diff] [blame]1535
1536<ul>
1537 <li>If <var>write<sub>1</sub></var> happens before
1538 <var>write<sub>2</sub></var>, and <var>write<sub>2</sub></var> happens
1539 before <var>R<sub>byte</sub></var>, then <var>R<sub>byte</sub></var>
Eli Friedman118973a2011-07-22 03:04:45 +0000[diff] [blame]1540 does not see <var>write<sub>1</sub></var>.
Bill Wendling0246bb72011-07-31 06:45:03 +0000[diff] [blame]1541 <li>If <var>R<sub>byte</sub></var> happens before
1542 <var>write<sub>3</sub></var>, then <var>R<sub>byte</sub></var> does not
1543 see <var>write<sub>3</sub></var>.
Eli Friedman5b60e1b2011-07-20 21:35:53 +0000[diff] [blame]1544</ul>
1545
1546<p>Given that definition, <var>R<sub>byte</sub></var> is defined as follows:
1547<ul>
Eli Friedman234bccd2011-08-22 21:35:27 +0000[diff] [blame]1548 <li>If <var>R</var> is volatile, the result is target-dependent. (Volatile
1549 is supposed to give guarantees which can support
1550 <code>sig_atomic_t</code> in C/C++, and may be used for accesses to
1551 addresses which do not behave like normal memory. It does not generally
1552 provide cross-thread synchronization.)
1553 <li>Otherwise, if there is no write to the same byte that happens before
Eli Friedman5b60e1b2011-07-20 21:35:53 +0000[diff] [blame]1554 <var>R<sub>byte</sub></var>, <var>R<sub>byte</sub></var> returns
1555 <tt>undef</tt> for that byte.
Eli Friedman118973a2011-07-22 03:04:45 +0000[diff] [blame]1556 <li>Otherwise, if <var>R<sub>byte</sub></var> may see exactly one write,
Eli Friedman5b60e1b2011-07-20 21:35:53 +0000[diff] [blame]1557 <var>R<sub>byte</sub></var> returns the value written by that
1558 write.</li>
Eli Friedman118973a2011-07-22 03:04:45 +0000[diff] [blame]1559 <li>Otherwise, if <var>R</var> is atomic, and all the writes
1560 <var>R<sub>byte</sub></var> may see are atomic, it chooses one of the
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1561 values written. See the <a href="#ordering">Atomic Memory Ordering
1562 Constraints</a> section for additional constraints on how the choice
1563 is made.
Eli Friedman5b60e1b2011-07-20 21:35:53 +0000[diff] [blame]1564 <li>Otherwise <var>R<sub>byte</sub></var> returns <tt>undef</tt>.</li>
1565</ul>
1566
1567<p><var>R</var> returns the value composed of the series of bytes it read.
1568This implies that some bytes within the value may be <tt>undef</tt>
1569<b>without</b> the entire value being <tt>undef</tt>. Note that this only
1570defines the semantics of the operation; it doesn't mean that targets will
1571emit more than one instruction to read the series of bytes.</p>
1572
1573<p>Note that in cases where none of the atomic intrinsics are used, this model
1574places only one restriction on IR transformations on top of what is required
1575for single-threaded execution: introducing a store to a byte which might not
Eli Friedman101c81d2011-08-02 01:15:34 +0000[diff] [blame]1576otherwise be stored is not allowed in general. (Specifically, in the case
1577where another thread might write to and read from an address, introducing a
1578store can change a load that may see exactly one write into a load that may
1579see multiple writes.)</p>
Eli Friedman5b60e1b2011-07-20 21:35:53 +0000[diff] [blame]1580
1581<!-- FIXME: This model assumes all targets where concurrency is relevant have
1582a byte-size store which doesn't affect adjacent bytes. As far as I can tell,
1583none of the backends currently in the tree fall into this category; however,
1584there might be targets which care. If there are, we want a paragraph
1585like the following:
1586
1587Targets may specify that stores narrower than a certain width are not
1588available; on such a target, for the purposes of this model, treat any
1589non-atomic write with an alignment or width less than the minimum width
1590as if it writes to the relevant surrounding bytes.
1591-->
1592
1593</div>
1594
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1595<!-- ======================================================================= -->
NAKAMURA Takumib5bb29c2011-08-12 06:17:17 +0000[diff] [blame]1596<h3>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1597 <a name="ordering">Atomic Memory Ordering Constraints</a>
NAKAMURA Takumib5bb29c2011-08-12 06:17:17 +0000[diff] [blame]1598</h3>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1599
NAKAMURA Takumib5bb29c2011-08-12 06:17:17 +0000[diff] [blame]1600<div>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1601
1602<p>Atomic instructions (<a href="#i_cmpxchg"><code>cmpxchg</code></a>,
Eli Friedman21006d42011-08-09 23:02:53 +0000[diff] [blame]1603<a href="#i_atomicrmw"><code>atomicrmw</code></a>,
1604<a href="#i_fence"><code>fence</code></a>,
1605<a href="#i_load"><code>atomic load</code></a>, and
Eli Friedman8fa281a2011-08-09 23:26:12 +0000[diff] [blame]1606<a href="#i_store"><code>atomic store</code></a>) take an ordering parameter
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1607that determines which other atomic instructions on the same address they
1608<i>synchronize with</i>. These semantics are borrowed from Java and C++0x,
1609but are somewhat more colloquial. If these descriptions aren't precise enough,
Eli Friedman234bccd2011-08-22 21:35:27 +0000[diff] [blame]1610check those specs (see spec references in the
1611<a href="Atomic.html#introduction">atomics guide</a>).
1612<a href="#i_fence"><code>fence</code></a> instructions
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1613treat these orderings somewhat differently since they don't take an address.
1614See that instruction's documentation for details.</p>
1615
Eli Friedman234bccd2011-08-22 21:35:27 +0000[diff] [blame]1616<p>For a simpler introduction to the ordering constraints, see the
1617<a href="Atomics.html">LLVM Atomic Instructions and Concurrency Guide</a>.</p>
1618
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1619<dl>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1620<dt><code>unordered</code></dt>
1621<dd>The set of values that can be read is governed by the happens-before
1622partial order. A value cannot be read unless some operation wrote it.
1623This is intended to provide a guarantee strong enough to model Java's
1624non-volatile shared variables. This ordering cannot be specified for
1625read-modify-write operations; it is not strong enough to make them atomic
1626in any interesting way.</dd>
1627<dt><code>monotonic</code></dt>
1628<dd>In addition to the guarantees of <code>unordered</code>, there is a single
1629total order for modifications by <code>monotonic</code> operations on each
1630address. All modification orders must be compatible with the happens-before
1631order. There is no guarantee that the modification orders can be combined to
1632a global total order for the whole program (and this often will not be
1633possible). The read in an atomic read-modify-write operation
1634(<a href="#i_cmpxchg"><code>cmpxchg</code></a> and
1635<a href="#i_atomicrmw"><code>atomicrmw</code></a>)
1636reads the value in the modification order immediately before the value it
1637writes. If one atomic read happens before another atomic read of the same
1638address, the later read must see the same value or a later value in the
1639address's modification order. This disallows reordering of
1640<code>monotonic</code> (or stronger) operations on the same address. If an
1641address is written <code>monotonic</code>ally by one thread, and other threads
1642<code>monotonic</code>ally read that address repeatedly, the other threads must
Eli Friedman234bccd2011-08-22 21:35:27 +0000[diff] [blame]1643eventually see the write. This corresponds to the C++0x/C1x
1644<code>memory_order_relaxed</code>.</dd>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1645<dt><code>acquire</code></dt>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1646<dd>In addition to the guarantees of <code>monotonic</code>,
Eli Friedmanc264b2f2011-08-24 20:28:39 +0000[diff] [blame]1647a <i>synchronizes-with</i> edge may be formed with a <code>release</code>
1648operation. This is intended to model C++'s <code>memory_order_acquire</code>.</dd>
1649<dt><code>release</code></dt>
1650<dd>In addition to the guarantees of <code>monotonic</code>, if this operation
1651writes a value which is subsequently read by an <code>acquire</code> operation,
1652it <i>synchronizes-with</i> that operation. (This isn't a complete
1653description; see the C++0x definition of a release sequence.) This corresponds
1654to the C++0x/C1x <code>memory_order_release</code>.</dd>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1655<dt><code>acq_rel</code> (acquire+release)</dt><dd>Acts as both an
Eli Friedman234bccd2011-08-22 21:35:27 +0000[diff] [blame]1656<code>acquire</code> and <code>release</code> operation on its address.
1657This corresponds to the C++0x/C1x <code>memory_order_acq_rel</code>.</dd>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1658<dt><code>seq_cst</code> (sequentially consistent)</dt><dd>
1659<dd>In addition to the guarantees of <code>acq_rel</code>
1660(<code>acquire</code> for an operation which only reads, <code>release</code>
1661for an operation which only writes), there is a global total order on all
1662sequentially-consistent operations on all addresses, which is consistent with
1663the <i>happens-before</i> partial order and with the modification orders of
1664all the affected addresses. Each sequentially-consistent read sees the last
Eli Friedman234bccd2011-08-22 21:35:27 +0000[diff] [blame]1665preceding write to the same address in this global order. This corresponds
1666to the C++0x/C1x <code>memory_order_seq_cst</code> and Java volatile.</dd>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1667</dl>
1668
1669<p id="singlethread">If an atomic operation is marked <code>singlethread</code>,
1670it only <i>synchronizes with</i> or participates in modification and seq_cst
1671total orderings with other operations running in the same thread (for example,
1672in signal handlers).</p>
1673
1674</div>
1675
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1676</div>
1677
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1678<!-- *********************************************************************** -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1679<h2><a name="typesystem">Type System</a></h2>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1680<!-- *********************************************************************** -->
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1681
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1682<div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1683
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1684<p>The LLVM type system is one of the most important features of the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1685 intermediate representation. Being typed enables a number of optimizations
1686 to be performed on the intermediate representation directly, without having
1687 to do extra analyses on the side before the transformation. A strong type
1688 system makes it easier to read the generated code and enables novel analyses
1689 and transformations that are not feasible to perform on normal three address
1690 code representations.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1691
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1692<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1693<h3>
1694 <a name="t_classifications">Type Classifications</a>
1695</h3>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1696
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1697<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1698
1699<p>The types fall into a few useful classifications:</p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1700
1701<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1702 <tbody>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1703 <tr><th>Classification</th><th>Types</th></tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1704 <tr>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1705 <td><a href="#t_integer">integer</a></td>
Reid Spencer2b916312007-05-16 18:44:01 +0000[diff] [blame]1706 <td><tt>i1, i2, i3, ... i8, ... i16, ... i32, ... i64, ... </tt></td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1707 </tr>
1708 <tr>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1709 <td><a href="#t_floating">floating point</a></td>
1710 <td><tt>float, double, x86_fp80, fp128, ppc_fp128</tt></td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1711 </tr>
1712 <tr>
1713 <td><a name="t_firstclass">first class</a></td>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1714 <td><a href="#t_integer">integer</a>,
1715 <a href="#t_floating">floating point</a>,
1716 <a href="#t_pointer">pointer</a>,
Dan Gohman0066db62008-06-18 18:42:13 +0000[diff] [blame]1717 <a href="#t_vector">vector</a>,
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]1718 <a href="#t_struct">structure</a>,
1719 <a href="#t_array">array</a>,
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1720 <a href="#t_label">label</a>,
1721 <a href="#t_metadata">metadata</a>.
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1722 </td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1723 </tr>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1724 <tr>
1725 <td><a href="#t_primitive">primitive</a></td>
1726 <td><a href="#t_label">label</a>,
1727 <a href="#t_void">void</a>,
Tobias Grosser05387292010-12-28 20:29:31 +0000[diff] [blame]1728 <a href="#t_integer">integer</a>,
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1729 <a href="#t_floating">floating point</a>,
Dale Johannesen21fe99b2010-10-01 00:48:59 +0000[diff] [blame]1730 <a href="#t_x86mmx">x86mmx</a>,
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1731 <a href="#t_metadata">metadata</a>.</td>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1732 </tr>
1733 <tr>
1734 <td><a href="#t_derived">derived</a></td>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]1735 <td><a href="#t_array">array</a>,
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1736 <a href="#t_function">function</a>,
1737 <a href="#t_pointer">pointer</a>,
1738 <a href="#t_struct">structure</a>,
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1739 <a href="#t_vector">vector</a>,
1740 <a href="#t_opaque">opaque</a>.
Dan Gohman01ac1012008-10-14 16:32:04 +0000[diff] [blame]1741 </td>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1742 </tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1743 </tbody>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1744</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1745
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1746<p>The <a href="#t_firstclass">first class</a> types are perhaps the most
1747 important. Values of these types are the only ones which can be produced by
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]1748 instructions.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1749
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1750</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1751
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1752<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1753<h3>
1754 <a name="t_primitive">Primitive Types</a>
1755</h3>
Chris Lattner8f8c7b72008-01-04 04:34:14 +0000[diff] [blame]1756
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1757<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1758
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1759<p>The primitive types are the fundamental building blocks of the LLVM
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1760 system.</p>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1761
1762<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1763<h4>
1764 <a name="t_integer">Integer Type</a>
1765</h4>
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]1766
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1767<div>
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]1768
1769<h5>Overview:</h5>
1770<p>The integer type is a very simple type that simply specifies an arbitrary
1771 bit width for the integer type desired. Any bit width from 1 bit to
1772 2<sup>23</sup>-1 (about 8 million) can be specified.</p>
1773
1774<h5>Syntax:</h5>
1775<pre>
1776 iN
1777</pre>
1778
1779<p>The number of bits the integer will occupy is specified by the <tt>N</tt>
1780 value.</p>
1781
1782<h5>Examples:</h5>
1783<table class="layout">
1784 <tr class="layout">
1785 <td class="left"><tt>i1</tt></td>
1786 <td class="left">a single-bit integer.</td>
1787 </tr>
1788 <tr class="layout">
1789 <td class="left"><tt>i32</tt></td>
1790 <td class="left">a 32-bit integer.</td>
1791 </tr>
1792 <tr class="layout">
1793 <td class="left"><tt>i1942652</tt></td>
1794 <td class="left">a really big integer of over 1 million bits.</td>
1795 </tr>
1796</table>
1797
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]1798</div>
1799
1800<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1801<h4>
1802 <a name="t_floating">Floating Point Types</a>
1803</h4>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1804
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1805<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1806
1807<table>
1808 <tbody>
1809 <tr><th>Type</th><th>Description</th></tr>
1810 <tr><td><tt>float</tt></td><td>32-bit floating point value</td></tr>
1811 <tr><td><tt>double</tt></td><td>64-bit floating point value</td></tr>
1812 <tr><td><tt>fp128</tt></td><td>128-bit floating point value (112-bit mantissa)</td></tr>
1813 <tr><td><tt>x86_fp80</tt></td><td>80-bit floating point value (X87)</td></tr>
1814 <tr><td><tt>ppc_fp128</tt></td><td>128-bit floating point value (two 64-bits)</td></tr>
1815 </tbody>
1816</table>
1817
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1818</div>
1819
1820<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1821<h4>
1822 <a name="t_x86mmx">X86mmx Type</a>
1823</h4>
Dale Johannesen21fe99b2010-10-01 00:48:59 +0000[diff] [blame]1824
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1825<div>
Dale Johannesen21fe99b2010-10-01 00:48:59 +0000[diff] [blame]1826
1827<h5>Overview:</h5>
1828<p>The x86mmx type represents a value held in an MMX register on an x86 machine. The operations allowed on it are quite limited: parameters and return values, load and store, and bitcast. User-specified MMX instructions are represented as intrinsic or asm calls with arguments and/or results of this type. There are no arrays, vectors or constants of this type.</p>
1829
1830<h5>Syntax:</h5>
1831<pre>
Dale Johannesen473a8c82010-10-01 01:07:02 +0000[diff] [blame]1832 x86mmx
Dale Johannesen21fe99b2010-10-01 00:48:59 +0000[diff] [blame]1833</pre>
1834
1835</div>
1836
1837<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1838<h4>
1839 <a name="t_void">Void Type</a>
1840</h4>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1841
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1842<div>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1843
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1844<h5>Overview:</h5>
1845<p>The void type does not represent any value and has no size.</p>
1846
1847<h5>Syntax:</h5>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1848<pre>
1849 void
1850</pre>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1851
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1852</div>
1853
1854<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1855<h4>
1856 <a name="t_label">Label Type</a>
1857</h4>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1858
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1859<div>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1860
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1861<h5>Overview:</h5>
1862<p>The label type represents code labels.</p>
1863
1864<h5>Syntax:</h5>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1865<pre>
1866 label
1867</pre>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1868
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1869</div>
1870
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1871<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1872<h4>
1873 <a name="t_metadata">Metadata Type</a>
1874</h4>
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1875
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1876<div>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1877
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1878<h5>Overview:</h5>
Nick Lewyckyc261df92009-09-27 23:27:42 +0000[diff] [blame]1879<p>The metadata type represents embedded metadata. No derived types may be
1880 created from metadata except for <a href="#t_function">function</a>
1881 arguments.
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1882
1883<h5>Syntax:</h5>
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1884<pre>
1885 metadata
1886</pre>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1887
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1888</div>
1889
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1890</div>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1891
1892<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1893<h3>
1894 <a name="t_derived">Derived Types</a>
1895</h3>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1896
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1897<div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1898
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1899<p>The real power in LLVM comes from the derived types in the system. This is
1900 what allows a programmer to represent arrays, functions, pointers, and other
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]1901 useful types. Each of these types contain one or more element types which
1902 may be a primitive type, or another derived type. For example, it is
1903 possible to have a two dimensional array, using an array as the element type
1904 of another array.</p>
Dan Gohmand8791e52009-01-24 15:58:40 +0000[diff] [blame]1905
Chris Lattner1afcace2011-07-09 17:41:24 +0000[diff] [blame]1906</div>
1907
1908
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]1909<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1910<h4>
1911 <a name="t_aggregate">Aggregate Types</a>
1912</h4>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]1913
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1914<div>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]1915
1916<p>Aggregate Types are a subset of derived types that can contain multiple
1917 member types. <a href="#t_array">Arrays</a>,
Chris Lattner61c70e92010-08-28 04:09:24 +0000[diff] [blame]1918 <a href="#t_struct">structs</a>, and <a href="#t_vector">vectors</a> are
1919 aggregate types.</p>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]1920
1921</div>
1922
Reid Spencer2b916312007-05-16 18:44:01 +0000[diff] [blame]1923<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1924<h4>
1925 <a name="t_array">Array Type</a>
1926</h4>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1927
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1928<div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1929
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1930<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1931<p>The array type is a very simple derived type that arranges elements
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1932 sequentially in memory. The array type requires a size (number of elements)
1933 and an underlying data type.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1934
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1935<h5>Syntax:</h5>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1936<pre>
1937 [&lt;# elements&gt; x &lt;elementtype&gt;]
1938</pre>
1939
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1940<p>The number of elements is a constant integer value; <tt>elementtype</tt> may
1941 be any type with a size.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1942
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1943<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1944<table class="layout">
1945 <tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1946 <td class="left"><tt>[40 x i32]</tt></td>
1947 <td class="left">Array of 40 32-bit integer values.</td>
1948 </tr>
1949 <tr class="layout">
1950 <td class="left"><tt>[41 x i32]</tt></td>
1951 <td class="left">Array of 41 32-bit integer values.</td>
1952 </tr>
1953 <tr class="layout">
1954 <td class="left"><tt>[4 x i8]</tt></td>
1955 <td class="left">Array of 4 8-bit integer values.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1956 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1957</table>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1958<p>Here are some examples of multidimensional arrays:</p>
1959<table class="layout">
1960 <tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1961 <td class="left"><tt>[3 x [4 x i32]]</tt></td>
1962 <td class="left">3x4 array of 32-bit integer values.</td>
1963 </tr>
1964 <tr class="layout">
1965 <td class="left"><tt>[12 x [10 x float]]</tt></td>
1966 <td class="left">12x10 array of single precision floating point values.</td>
1967 </tr>
1968 <tr class="layout">
1969 <td class="left"><tt>[2 x [3 x [4 x i16]]]</tt></td>
1970 <td class="left">2x3x4 array of 16-bit integer values.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1971 </tr>
1972</table>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]1973
Dan Gohman7657f6b2009-11-09 19:01:53 +0000[diff] [blame]1974<p>There is no restriction on indexing beyond the end of the array implied by
1975 a static type (though there are restrictions on indexing beyond the bounds
1976 of an allocated object in some cases). This means that single-dimension
1977 'variable sized array' addressing can be implemented in LLVM with a zero
1978 length array type. An implementation of 'pascal style arrays' in LLVM could
1979 use the type "<tt>{ i32, [0 x float]}</tt>", for example.</p>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]1980
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1981</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1982
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1983<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1984<h4>
1985 <a name="t_function">Function Type</a>
1986</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1987
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1988<div>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]1989
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1990<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1991<p>The function type can be thought of as a function signature. It consists of
1992 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]1993 function type is a first class type or a void type.</p>
Devang Patelc3fc6df2008-03-10 20:49:15 +0000[diff] [blame]1994
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1995<h5>Syntax:</h5>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]1996<pre>
Nick Lewycky51386942009-09-27 07:55:32 +0000[diff] [blame]1997 &lt;returntype&gt; (&lt;parameter list&gt;)
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]1998</pre>
1999
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]2000<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]2001 specifiers. Optionally, the parameter list may include a type <tt>...</tt>,
2002 which indicates that the function takes a variable number of arguments.
2003 Variable argument functions can access their arguments with
2004 the <a href="#int_varargs">variable argument handling intrinsic</a>
Chris Lattner0724fbd2010-03-02 06:36:51 +0000[diff] [blame]2005 functions. '<tt>&lt;returntype&gt;</tt>' is any type except
Nick Lewyckyc261df92009-09-27 23:27:42 +0000[diff] [blame]2006 <a href="#t_label">label</a>.</p>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]2007
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2008<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]2009<table class="layout">
2010 <tr class="layout">
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]2011 <td class="left"><tt>i32 (i32)</tt></td>
2012 <td class="left">function taking an <tt>i32</tt>, returning an <tt>i32</tt>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]2013 </td>
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]2014 </tr><tr class="layout">
Chris Lattner0724fbd2010-03-02 06:36:51 +0000[diff] [blame]2015 <td class="left"><tt>float&nbsp;(i16,&nbsp;i32&nbsp;*)&nbsp;*
Reid Spencerf17a0b72006-12-31 07:20:23 +0000[diff] [blame]2016 </tt></td>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]2017 <td class="left"><a href="#t_pointer">Pointer</a> to a function that takes
Chris Lattner0724fbd2010-03-02 06:36:51 +0000[diff] [blame]2018 an <tt>i16</tt> and a <a href="#t_pointer">pointer</a> to <tt>i32</tt>,
2019 returning <tt>float</tt>.
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]2020 </td>
2021 </tr><tr class="layout">
2022 <td class="left"><tt>i32 (i8*, ...)</tt></td>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]2023 <td class="left">A vararg function that takes at least one
2024 <a href="#t_pointer">pointer</a> to <tt>i8 </tt> (char in C),
2025 which returns an integer. This is the signature for <tt>printf</tt> in
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]2026 LLVM.
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]2027 </td>
Devang Patela582f402008-03-24 05:35:41 +0000[diff] [blame]2028 </tr><tr class="layout">
2029 <td class="left"><tt>{i32, i32} (i32)</tt></td>
Nick Lewycky51386942009-09-27 07:55:32 +0000[diff] [blame]2030 <td class="left">A function taking an <tt>i32</tt>, returning a
2031 <a href="#t_struct">structure</a> containing two <tt>i32</tt> values
Devang Patela582f402008-03-24 05:35:41 +0000[diff] [blame]2032 </td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]2033 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2034</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]2035
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2036</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2037
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2038<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2039<h4>
2040 <a name="t_struct">Structure Type</a>
2041</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2042
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2043<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2044
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2045<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2046<p>The structure type is used to represent a collection of data members together
Chris Lattner1afcace2011-07-09 17:41:24 +0000[diff] [blame]2047 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]2048
Jeffrey Yasskin7a088cf2010-01-11 19:19:26 +0000[diff] [blame]2049<p>Structures in memory are accessed using '<tt><a href="#i_load">load</a></tt>'
2050 and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a field
2051 with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.
2052 Structures in registers are accessed using the
2053 '<tt><a href="#i_extractvalue">extractvalue</a></tt>' and
2054 '<tt><a href="#i_insertvalue">insertvalue</a></tt>' instructions.</p>
Chris Lattner1afcace2011-07-09 17:41:24 +0000[diff] [blame]2055
2056<p>Structures may optionally be "packed" structures, which indicate that the
2057 alignment of the struct is one byte, and that there is no padding between
Chris Lattner2c38d652011-08-12 17:31:02 +0000[diff] [blame]2058 the elements. In non-packed structs, padding between field types is inserted
2059 as defined by the TargetData string in the module, which is required to match
Chris Lattnere4617b02011-10-11 23:02:17 +0000[diff] [blame]2060 what the underlying code generator expects.</p>
Chris Lattner1afcace2011-07-09 17:41:24 +0000[diff] [blame]2061
Chris Lattner2c38d652011-08-12 17:31:02 +0000[diff] [blame]2062<p>Structures can either be "literal" or "identified". A literal structure is
2063 defined inline with other types (e.g. <tt>{i32, i32}*</tt>) whereas identified
2064 types are always defined at the top level with a name. Literal types are
2065 uniqued by their contents and can never be recursive or opaque since there is
Chris Lattneraa175c32011-08-12 18:12:40 +0000[diff] [blame]2066 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]2067 never uniqued.
Chris Lattner1afcace2011-07-09 17:41:24 +0000[diff] [blame]2068</p>
2069
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2070<h5>Syntax:</h5>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]2071<pre>
Chris Lattner2c38d652011-08-12 17:31:02 +0000[diff] [blame]2072 %T1 = type { &lt;type list&gt; } <i>; Identified normal struct type</i>
2073 %T2 = type &lt;{ &lt;type list&gt; }&gt; <i>; Identified packed struct type</i>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]2074</pre>
Chris Lattner1afcace2011-07-09 17:41:24 +0000[diff] [blame]2075
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2076<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]2077<table class="layout">
2078 <tr class="layout">
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]2079 <td class="left"><tt>{ i32, i32, i32 }</tt></td>
2080 <td class="left">A triple of three <tt>i32</tt> values</td>
Chris Lattner1afcace2011-07-09 17:41:24 +0000[diff] [blame]2081 </tr>
2082 <tr class="layout">
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]2083 <td class="left"><tt>{&nbsp;float,&nbsp;i32&nbsp;(i32)&nbsp;*&nbsp;}</tt></td>
2084 <td class="left">A pair, where the first element is a <tt>float</tt> and the
2085 second element is a <a href="#t_pointer">pointer</a> to a
2086 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
2087 an <tt>i32</tt>.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]2088 </tr>
Chris Lattner1afcace2011-07-09 17:41:24 +0000[diff] [blame]2089 <tr class="layout">
2090 <td class="left"><tt>&lt;{ i8, i32 }&gt;</tt></td>
2091 <td class="left">A packed struct known to be 5 bytes in size.</td>
2092 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2093</table>
Dan Gohmand8791e52009-01-24 15:58:40 +0000[diff] [blame]2094
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2095</div>
Chris Lattner1afcace2011-07-09 17:41:24 +0000[diff] [blame]2096
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2097<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2098<h4>
Chris Lattner628ed392011-07-23 19:59:08 +0000[diff] [blame]2099 <a name="t_opaque">Opaque Structure Types</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2100</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2101
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2102<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2103
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]2104<h5>Overview:</h5>
Chris Lattner628ed392011-07-23 19:59:08 +0000[diff] [blame]2105<p>Opaque structure types are used to represent named structure types that do
2106 not have a body specified. This corresponds (for example) to the C notion of
2107 a forward declared structure.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2108
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]2109<h5>Syntax:</h5>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]2110<pre>
Chris Lattner1afcace2011-07-09 17:41:24 +0000[diff] [blame]2111 %X = type opaque
2112 %52 = type opaque
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]2113</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2114
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]2115<h5>Examples:</h5>
2116<table class="layout">
2117 <tr class="layout">
Chris Lattner1afcace2011-07-09 17:41:24 +0000[diff] [blame]2118 <td class="left"><tt>opaque</tt></td>
2119 <td class="left">An opaque type.</td>
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]2120 </tr>
2121</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2122
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]2123</div>
2124
Chris Lattner1afcace2011-07-09 17:41:24 +0000[diff] [blame]2125
2126
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]2127<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2128<h4>
2129 <a name="t_pointer">Pointer Type</a>
2130</h4>
Chris Lattner0fd4a272009-02-08 19:53:29 +0000[diff] [blame]2131
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2132<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2133
2134<h5>Overview:</h5>
Dan Gohmanff3ef322010-02-25 16:50:07 +0000[diff] [blame]2135<p>The pointer type is used to specify memory locations.
2136 Pointers are commonly used to reference objects in memory.</p>
2137
2138<p>Pointer types may have an optional address space attribute defining the
2139 numbered address space where the pointed-to object resides. The default
2140 address space is number zero. The semantics of non-zero address
2141 spaces are target-specific.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2142
2143<p>Note that LLVM does not permit pointers to void (<tt>void*</tt>) nor does it
2144 permit pointers to labels (<tt>label*</tt>). Use <tt>i8*</tt> instead.</p>
Chris Lattner0fd4a272009-02-08 19:53:29 +0000[diff] [blame]2145
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2146<h5>Syntax:</h5>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]2147<pre>
2148 &lt;type&gt; *
2149</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2150
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2151<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]2152<table class="layout">
2153 <tr class="layout">
Dan Gohman2a08c532009-01-04 23:44:43 +0000[diff] [blame]2154 <td class="left"><tt>[4 x i32]*</tt></td>
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]2155 <td class="left">A <a href="#t_pointer">pointer</a> to <a
2156 href="#t_array">array</a> of four <tt>i32</tt> values.</td>
2157 </tr>
2158 <tr class="layout">
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]2159 <td class="left"><tt>i32 (i32*) *</tt></td>
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]2160 <td class="left"> A <a href="#t_pointer">pointer</a> to a <a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2161 href="#t_function">function</a> that takes an <tt>i32*</tt>, returning an
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]2162 <tt>i32</tt>.</td>
2163 </tr>
2164 <tr class="layout">
2165 <td class="left"><tt>i32 addrspace(5)*</tt></td>
2166 <td class="left">A <a href="#t_pointer">pointer</a> to an <tt>i32</tt> value
2167 that resides in address space #5.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]2168 </tr>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2169</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2170
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2171</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]2172
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]2173<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2174<h4>
2175 <a name="t_vector">Vector Type</a>
2176</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2177
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2178<div>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]2179
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]2180<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2181<p>A vector type is a simple derived type that represents a vector of elements.
2182 Vector types are used when multiple primitive data are operated in parallel
2183 using a single instruction (SIMD). A vector type requires a size (number of
Duncan Sandsd40d14e2009-11-27 13:38:03 +0000[diff] [blame]2184 elements) and an underlying primitive data type. Vector types are considered
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2185 <a href="#t_firstclass">first class</a>.</p>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]2186
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]2187<h5>Syntax:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]2188<pre>
2189 &lt; &lt;# elements&gt; x &lt;elementtype&gt; &gt;
2190</pre>
2191
Chris Lattner7d2e7be2010-10-10 18:20:35 +0000[diff] [blame]2192<p>The number of elements is a constant integer value larger than 0; elementtype
2193 may be any integer or floating point type. Vectors of size zero are not
2194 allowed, and pointers are not allowed as the element type.</p>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]2195
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]2196<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]2197<table class="layout">
2198 <tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]2199 <td class="left"><tt>&lt;4 x i32&gt;</tt></td>
2200 <td class="left">Vector of 4 32-bit integer values.</td>
2201 </tr>
2202 <tr class="layout">
2203 <td class="left"><tt>&lt;8 x float&gt;</tt></td>
2204 <td class="left">Vector of 8 32-bit floating-point values.</td>
2205 </tr>
2206 <tr class="layout">
2207 <td class="left"><tt>&lt;2 x i64&gt;</tt></td>
2208 <td class="left">Vector of 2 64-bit integer values.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]2209 </tr>
2210</table>
Dan Gohmand8791e52009-01-24 15:58:40 +0000[diff] [blame]2211
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2212</div>
2213
Bill Wendlingaf75f0c2011-07-31 06:47:33 +0000[diff] [blame]2214</div>
2215
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2216<!-- *********************************************************************** -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2217<h2><a name="constants">Constants</a></h2>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2218<!-- *********************************************************************** -->
2219
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2220<div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2221
2222<p>LLVM has several different basic types of constants. This section describes
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2223 them all and their syntax.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2224
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2225<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2226<h3>
2227 <a name="simpleconstants">Simple Constants</a>
2228</h3>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2229
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2230<div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2231
2232<dl>
2233 <dt><b>Boolean constants</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2234 <dd>The two strings '<tt>true</tt>' and '<tt>false</tt>' are both valid
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]2235 constants of the <tt><a href="#t_integer">i1</a></tt> type.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2236
2237 <dt><b>Integer constants</b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2238 <dd>Standard integers (such as '4') are constants of
2239 the <a href="#t_integer">integer</a> type. Negative numbers may be used
2240 with integer types.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2241
2242 <dt><b>Floating point constants</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2243 <dd>Floating point constants use standard decimal notation (e.g. 123.421),
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2244 exponential notation (e.g. 1.23421e+2), or a more precise hexadecimal
2245 notation (see below). The assembler requires the exact decimal value of a
2246 floating-point constant. For example, the assembler accepts 1.25 but
2247 rejects 1.3 because 1.3 is a repeating decimal in binary. Floating point
2248 constants must have a <a href="#t_floating">floating point</a> type. </dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2249
2250 <dt><b>Null pointer constants</b></dt>
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]2251 <dd>The identifier '<tt>null</tt>' is recognized as a null pointer constant
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2252 and must be of <a href="#t_pointer">pointer type</a>.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2253</dl>
2254
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2255<p>The one non-intuitive notation for constants is the hexadecimal form of
2256 floating point constants. For example, the form '<tt>double
2257 0x432ff973cafa8000</tt>' is equivalent to (but harder to read than)
2258 '<tt>double 4.5e+15</tt>'. The only time hexadecimal floating point
2259 constants are required (and the only time that they are generated by the
2260 disassembler) is when a floating point constant must be emitted but it cannot
2261 be represented as a decimal floating point number in a reasonable number of
2262 digits. For example, NaN's, infinities, and other special values are
2263 represented in their IEEE hexadecimal format so that assembly and disassembly
2264 do not cause any bits to change in the constants.</p>
2265
Dale Johannesenbd5e5a82009-02-11 22:14:51 +0000[diff] [blame]2266<p>When using the hexadecimal form, constants of types float and double are
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2267 represented using the 16-digit form shown above (which matches the IEEE754
2268 representation for double); float values must, however, be exactly
2269 representable as IEE754 single precision. Hexadecimal format is always used
2270 for long double, and there are three forms of long double. The 80-bit format
2271 used by x86 is represented as <tt>0xK</tt> followed by 20 hexadecimal digits.
2272 The 128-bit format used by PowerPC (two adjacent doubles) is represented
2273 by <tt>0xM</tt> followed by 32 hexadecimal digits. The IEEE 128-bit format
2274 is represented by <tt>0xL</tt> followed by 32 hexadecimal digits; no
2275 currently supported target uses this format. Long doubles will only work if
2276 they match the long double format on your target. All hexadecimal formats
2277 are big-endian (sign bit at the left).</p>
2278
Dale Johannesen21fe99b2010-10-01 00:48:59 +0000[diff] [blame]2279<p>There are no constants of type x86mmx.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2280</div>
2281
2282<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2283<h3>
Bill Wendlingd9fe2982009-07-20 02:32:41 +0000[diff] [blame]2284<a name="aggregateconstants"></a> <!-- old anchor -->
2285<a name="complexconstants">Complex Constants</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2286</h3>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2287
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2288<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2289
Chris Lattner70882792009-02-28 18:32:25 +0000[diff] [blame]2290<p>Complex constants are a (potentially recursive) combination of simple
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2291 constants and smaller complex constants.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2292
2293<dl>
2294 <dt><b>Structure constants</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2295 <dd>Structure constants are represented with notation similar to structure
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2296 type definitions (a comma separated list of elements, surrounded by braces
2297 (<tt>{}</tt>)). For example: "<tt>{ i32 4, float 17.0, i32* @G }</tt>",
2298 where "<tt>@G</tt>" is declared as "<tt>@G = external global i32</tt>".
2299 Structure constants must have <a href="#t_struct">structure type</a>, and
2300 the number and types of elements must match those specified by the
2301 type.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2302
2303 <dt><b>Array constants</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2304 <dd>Array constants are represented with notation similar to array type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2305 definitions (a comma separated list of elements, surrounded by square
2306 brackets (<tt>[]</tt>)). For example: "<tt>[ i32 42, i32 11, i32 74
2307 ]</tt>". Array constants must have <a href="#t_array">array type</a>, and
2308 the number and types of elements must match those specified by the
2309 type.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2310
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2311 <dt><b>Vector constants</b></dt>
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2312 <dd>Vector constants are represented with notation similar to vector type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2313 definitions (a comma separated list of elements, surrounded by
2314 less-than/greater-than's (<tt>&lt;&gt;</tt>)). For example: "<tt>&lt; i32
2315 42, i32 11, i32 74, i32 100 &gt;</tt>". Vector constants must
2316 have <a href="#t_vector">vector type</a>, and the number and types of
2317 elements must match those specified by the type.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2318
2319 <dt><b>Zero initialization</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2320 <dd>The string '<tt>zeroinitializer</tt>' can be used to zero initialize a
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]2321 value to zero of <em>any</em> type, including scalar and
2322 <a href="#t_aggregate">aggregate</a> types.
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2323 This is often used to avoid having to print large zero initializers
2324 (e.g. for large arrays) and is always exactly equivalent to using explicit
2325 zero initializers.</dd>
Nick Lewycky21cc4462009-04-04 07:22:01 +0000[diff] [blame]2326
2327 <dt><b>Metadata node</b></dt>
Nick Lewycky1e8c7a62009-05-30 16:08:30 +0000[diff] [blame]2328 <dd>A metadata node is a structure-like constant with
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2329 <a href="#t_metadata">metadata type</a>. For example: "<tt>metadata !{
2330 i32 0, metadata !"test" }</tt>". Unlike other constants that are meant to
2331 be interpreted as part of the instruction stream, metadata is a place to
2332 attach additional information such as debug info.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2333</dl>
2334
2335</div>
2336
2337<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2338<h3>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2339 <a name="globalconstants">Global Variable and Function Addresses</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2340</h3>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2341
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2342<div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2343
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2344<p>The addresses of <a href="#globalvars">global variables</a>
2345 and <a href="#functionstructure">functions</a> are always implicitly valid
2346 (link-time) constants. These constants are explicitly referenced when
2347 the <a href="#identifiers">identifier for the global</a> is used and always
2348 have <a href="#t_pointer">pointer</a> type. For example, the following is a
2349 legal LLVM file:</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2350
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2351<pre class="doc_code">
Chris Lattnera18a4242007-06-06 18:28:13 +0000[diff] [blame]2352@X = global i32 17
2353@Y = global i32 42
2354@Z = global [2 x i32*] [ i32* @X, i32* @Y ]
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2355</pre>
2356
2357</div>
2358
2359<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2360<h3>
2361 <a name="undefvalues">Undefined Values</a>
2362</h3>
2363
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2364<div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2365
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2366<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]2367 indicates that the user of the value may receive an unspecified bit-pattern.
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]2368 Undefined values may be of any type (other than '<tt>label</tt>'
2369 or '<tt>void</tt>') and be used anywhere a constant is permitted.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2370
Chris Lattnerc608cb12009-09-11 01:49:31 +0000[diff] [blame]2371<p>Undefined values are useful because they indicate to the compiler that the
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2372 program is well defined no matter what value is used. This gives the
2373 compiler more freedom to optimize. Here are some examples of (potentially
2374 surprising) transformations that are valid (in pseudo IR):</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2375
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2376
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2377<pre class="doc_code">
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2378 %A = add %X, undef
2379 %B = sub %X, undef
2380 %C = xor %X, undef
2381Safe:
2382 %A = undef
2383 %B = undef
2384 %C = undef
2385</pre>
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2386
2387<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]2388 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]2389
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2390<pre class="doc_code">
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2391 %A = or %X, undef
2392 %B = and %X, undef
2393Safe:
2394 %A = -1
2395 %B = 0
2396Unsafe:
2397 %A = undef
2398 %B = undef
2399</pre>
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2400
2401<p>These logical operations have bits that are not always affected by the input.
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]2402 For example, if <tt>%X</tt> has a zero bit, then the output of the
2403 '<tt>and</tt>' operation will always be a zero for that bit, no matter what
2404 the corresponding bit from the '<tt>undef</tt>' is. As such, it is unsafe to
2405 optimize or assume that the result of the '<tt>and</tt>' is '<tt>undef</tt>'.
2406 However, it is safe to assume that all bits of the '<tt>undef</tt>' could be
2407 0, and optimize the '<tt>and</tt>' to 0. Likewise, it is safe to assume that
2408 all the bits of the '<tt>undef</tt>' operand to the '<tt>or</tt>' could be
2409 set, allowing the '<tt>or</tt>' to be folded to -1.</p>
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2410
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2411<pre class="doc_code">
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2412 %A = select undef, %X, %Y
2413 %B = select undef, 42, %Y
2414 %C = select %X, %Y, undef
2415Safe:
2416 %A = %X (or %Y)
2417 %B = 42 (or %Y)
2418 %C = %Y
2419Unsafe:
2420 %A = undef
2421 %B = undef
2422 %C = undef
2423</pre>
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2424
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]2425<p>This set of examples shows that undefined '<tt>select</tt>' (and conditional
2426 branch) conditions can go <em>either way</em>, but they have to come from one
2427 of the two operands. In the <tt>%A</tt> example, if <tt>%X</tt> and
2428 <tt>%Y</tt> were both known to have a clear low bit, then <tt>%A</tt> would
2429 have to have a cleared low bit. However, in the <tt>%C</tt> example, the
2430 optimizer is allowed to assume that the '<tt>undef</tt>' operand could be the
2431 same as <tt>%Y</tt>, allowing the whole '<tt>select</tt>' to be
2432 eliminated.</p>
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2433
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2434<pre class="doc_code">
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2435 %A = xor undef, undef
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]2436
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2437 %B = undef
2438 %C = xor %B, %B
2439
2440 %D = undef
2441 %E = icmp lt %D, 4
2442 %F = icmp gte %D, 4
2443
2444Safe:
2445 %A = undef
2446 %B = undef
2447 %C = undef
2448 %D = undef
2449 %E = undef
2450 %F = undef
2451</pre>
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2452
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]2453<p>This example points out that two '<tt>undef</tt>' operands are not
2454 necessarily the same. This can be surprising to people (and also matches C
2455 semantics) where they assume that "<tt>X^X</tt>" is always zero, even
2456 if <tt>X</tt> is undefined. This isn't true for a number of reasons, but the
2457 short answer is that an '<tt>undef</tt>' "variable" can arbitrarily change
2458 its value over its "live range". This is true because the variable doesn't
2459 actually <em>have a live range</em>. Instead, the value is logically read
2460 from arbitrary registers that happen to be around when needed, so the value
2461 is not necessarily consistent over time. In fact, <tt>%A</tt> and <tt>%C</tt>
2462 need to have the same semantics or the core LLVM "replace all uses with"
2463 concept would not hold.</p>
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2464
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2465<pre class="doc_code">
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2466 %A = fdiv undef, %X
2467 %B = fdiv %X, undef
2468Safe:
2469 %A = undef
2470b: unreachable
2471</pre>
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2472
2473<p>These examples show the crucial difference between an <em>undefined
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]2474 value</em> and <em>undefined behavior</em>. An undefined value (like
2475 '<tt>undef</tt>') is allowed to have an arbitrary bit-pattern. This means that
2476 the <tt>%A</tt> operation can be constant folded to '<tt>undef</tt>', because
2477 the '<tt>undef</tt>' could be an SNaN, and <tt>fdiv</tt> is not (currently)
2478 defined on SNaN's. However, in the second example, we can make a more
2479 aggressive assumption: because the <tt>undef</tt> is allowed to be an
2480 arbitrary value, we are allowed to assume that it could be zero. Since a
2481 divide by zero has <em>undefined behavior</em>, we are allowed to assume that
2482 the operation does not execute at all. This allows us to delete the divide and
2483 all code after it. Because the undefined operation "can't happen", the
2484 optimizer can assume that it occurs in dead code.</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]2485
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2486<pre class="doc_code">
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2487a: store undef -> %X
2488b: store %X -> undef
2489Safe:
2490a: &lt;deleted&gt;
2491b: unreachable
2492</pre>
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2493
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]2494<p>These examples reiterate the <tt>fdiv</tt> example: a store <em>of</em> an
2495 undefined value can be assumed to not have any effect; we can assume that the
2496 value is overwritten with bits that happen to match what was already there.
2497 However, a store <em>to</em> an undefined location could clobber arbitrary
2498 memory, therefore, it has undefined behavior.</p>
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2499
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2500</div>
2501
2502<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2503<h3>
2504 <a name="trapvalues">Trap Values</a>
2505</h3>
2506
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2507<div>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]2508
Dan Gohmanc68ce062010-04-26 20:21:21 +0000[diff] [blame]2509<p>Trap values are similar to <a href="#undefvalues">undef values</a>, however
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]2510 instead of representing an unspecified bit pattern, they represent the
2511 fact that an instruction or constant expression which cannot evoke side
2512 effects has nevertheless detected a condition which results in undefined
Dan Gohmanc68ce062010-04-26 20:21:21 +0000[diff] [blame]2513 behavior.</p>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]2514
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2515<p>There is currently no way of representing a trap value in the IR; they
Dan Gohman855abed2010-05-03 14:51:43 +0000[diff] [blame]2516 only exist when produced by operations such as
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2517 <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]2518
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2519<p>Trap value behavior is defined in terms of value <i>dependence</i>:</p>
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2520
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2521<ul>
2522<li>Values other than <a href="#i_phi"><tt>phi</tt></a> nodes depend on
2523 their operands.</li>
2524
2525<li><a href="#i_phi"><tt>Phi</tt></a> nodes depend on the operand corresponding
2526 to their dynamic predecessor basic block.</li>
2527
2528<li>Function arguments depend on the corresponding actual argument values in
2529 the dynamic callers of their functions.</li>
2530
2531<li><a href="#i_call"><tt>Call</tt></a> instructions depend on the
2532 <a href="#i_ret"><tt>ret</tt></a> instructions that dynamically transfer
2533 control back to them.</li>
2534
Dan Gohmanb5328162010-05-03 14:55:22 +0000[diff] [blame]2535<li><a href="#i_invoke"><tt>Invoke</tt></a> instructions depend on the
2536 <a href="#i_ret"><tt>ret</tt></a>, <a href="#i_unwind"><tt>unwind</tt></a>,
2537 or exception-throwing call instructions that dynamically transfer control
2538 back to them.</li>
2539
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2540<li>Non-volatile loads and stores depend on the most recent stores to all of the
2541 referenced memory addresses, following the order in the IR
2542 (including loads and stores implied by intrinsics such as
2543 <a href="#int_memcpy"><tt>@llvm.memcpy</tt></a>.)</li>
2544
Dan Gohman7c24ff12010-05-03 14:59:34 +0000[diff] [blame]2545<!-- TODO: In the case of multiple threads, this only applies if the store
2546 "happens-before" the load or store. -->
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2547
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2548<!-- TODO: floating-point exception state -->
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2549
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2550<li>An instruction with externally visible side effects depends on the most
2551 recent preceding instruction with externally visible side effects, following
Dan Gohmanff70fe42010-07-06 15:26:33 +0000[diff] [blame]2552 the order in the IR. (This includes
2553 <a href="#volatile">volatile operations</a>.)</li>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]2554
Dan Gohmanb5328162010-05-03 14:55:22 +0000[diff] [blame]2555<li>An instruction <i>control-depends</i> on a
2556 <a href="#terminators">terminator instruction</a>
2557 if the terminator instruction has multiple successors and the instruction
2558 is always executed when control transfers to one of the successors, and
Chris Lattner7a2bdde2011-04-15 05:18:47 +0000[diff] [blame]2559 may not be executed when control is transferred to another.</li>
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2560
Dan Gohmanca4cac42011-04-12 23:05:59 +0000[diff] [blame]2561<li>Additionally, an instruction also <i>control-depends</i> on a terminator
2562 instruction if the set of instructions it otherwise depends on would be
Chris Lattner7a2bdde2011-04-15 05:18:47 +0000[diff] [blame]2563 different if the terminator had transferred control to a different
Dan Gohmanca4cac42011-04-12 23:05:59 +0000[diff] [blame]2564 successor.</li>
2565
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2566<li>Dependence is transitive.</li>
2567
2568</ul>
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2569
2570<p>Whenever a trap value is generated, all values which depend on it evaluate
Lang Hames87d5cb82011-10-13 23:04:49 +0000[diff] [blame]2571 to trap. If they have side effects, they evoke their side effects as if each
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2572 operand with a trap value were undef. If they have externally-visible side
2573 effects, the behavior is undefined.</p>
2574
2575<p>Here are some examples:</p>
Dan Gohmanc30f6e12010-04-26 20:54:53 +0000[diff] [blame]2576
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2577<pre class="doc_code">
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2578entry:
2579 %trap = sub nuw i32 0, 1 ; Results in a trap value.
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2580 %still_trap = and i32 %trap, 0 ; Whereas (and i32 undef, 0) would return 0.
2581 %trap_yet_again = getelementptr i32* @h, i32 %still_trap
2582 store i32 0, i32* %trap_yet_again ; undefined behavior
2583
2584 store i32 %trap, i32* @g ; Trap value conceptually stored to memory.
2585 %trap2 = load i32* @g ; Returns a trap value, not just undef.
2586
2587 volatile store i32 %trap, i32* @g ; External observation; undefined behavior.
2588
2589 %narrowaddr = bitcast i32* @g to i16*
2590 %wideaddr = bitcast i32* @g to i64*
Nick Lewycky64f9fb12011-05-16 19:29:30 +0000[diff] [blame]2591 %trap3 = load i16* %narrowaddr ; Returns a trap value.
2592 %trap4 = load i64* %wideaddr ; Returns a trap value.
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2593
Nick Lewycky64f9fb12011-05-16 19:29:30 +0000[diff] [blame]2594 %cmp = icmp slt i32 %trap, 0 ; Returns a trap value.
2595 br i1 %cmp, label %true, label %end ; Branch to either destination.
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2596
2597true:
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2598 volatile store i32 0, i32* @g ; This is control-dependent on %cmp, so
2599 ; it has undefined behavior.
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2600 br label %end
2601
2602end:
2603 %p = phi i32 [ 0, %entry ], [ 1, %true ]
2604 ; Both edges into this PHI are
2605 ; control-dependent on %cmp, so this
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2606 ; always results in a trap value.
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2607
Dan Gohmanca4cac42011-04-12 23:05:59 +0000[diff] [blame]2608 volatile store i32 0, i32* @g ; This would depend on the store in %true
2609 ; if %cmp is true, or the store in %entry
2610 ; otherwise, so this is undefined behavior.
2611
Nick Lewycky64f9fb12011-05-16 19:29:30 +0000[diff] [blame]2612 br i1 %cmp, label %second_true, label %second_end
Dan Gohmanca4cac42011-04-12 23:05:59 +0000[diff] [blame]2613 ; The same branch again, but this time the
2614 ; true block doesn't have side effects.
2615
2616second_true:
2617 ; No side effects!
Nick Lewycky64f9fb12011-05-16 19:29:30 +0000[diff] [blame]2618 ret void
Dan Gohmanca4cac42011-04-12 23:05:59 +0000[diff] [blame]2619
2620second_end:
2621 volatile store i32 0, i32* @g ; This time, the instruction always depends
2622 ; on the store in %end. Also, it is
2623 ; control-equivalent to %end, so this is
Nick Lewycky64f9fb12011-05-16 19:29:30 +0000[diff] [blame]2624 ; well-defined (again, ignoring earlier
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2625 ; undefined behavior in this example).
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2626</pre>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]2627
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]2628</div>
2629
2630<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2631<h3>
2632 <a name="blockaddress">Addresses of Basic Blocks</a>
2633</h3>
2634
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2635<div>
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]2636
Chris Lattnercdfc9402009-11-01 01:27:45 +0000[diff] [blame]2637<p><b><tt>blockaddress(@function, %block)</tt></b></p>
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]2638
2639<p>The '<tt>blockaddress</tt>' constant computes the address of the specified
Chris Lattner2dfdf2a2009-10-27 21:49:40 +0000[diff] [blame]2640 basic block in the specified function, and always has an i8* type. Taking
Chris Lattnercdfc9402009-11-01 01:27:45 +0000[diff] [blame]2641 the address of the entry block is illegal.</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]2642
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]2643<p>This value only has defined behavior when used as an operand to the
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]2644 '<a href="#i_indirectbr"><tt>indirectbr</tt></a>' instruction, or for
2645 comparisons against null. Pointer equality tests between labels addresses
2646 results in undefined behavior &mdash; though, again, comparison against null
2647 is ok, and no label is equal to the null pointer. This may be passed around
2648 as an opaque pointer sized value as long as the bits are not inspected. This
2649 allows <tt>ptrtoint</tt> and arithmetic to be performed on these values so
2650 long as the original value is reconstituted before the <tt>indirectbr</tt>
2651 instruction.</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]2652
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]2653<p>Finally, some targets may provide defined semantics when using the value as
2654 the operand to an inline assembly, but that is target specific.</p>
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]2655
2656</div>
2657
2658
2659<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2660<h3>
2661 <a name="constantexprs">Constant Expressions</a>
2662</h3>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2663
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2664<div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2665
2666<p>Constant expressions are used to allow expressions involving other constants
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2667 to be used as constants. Constant expressions may be of
2668 any <a href="#t_firstclass">first class</a> type and may involve any LLVM
2669 operation that does not have side effects (e.g. load and call are not
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]2670 supported). The following is the syntax for constant expressions:</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2671
2672<dl>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2673 <dt><b><tt>trunc (CST to TYPE)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2674 <dd>Truncate a constant to another type. The bit size of CST must be larger
2675 than the bit size of TYPE. Both types must be integers.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2676
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2677 <dt><b><tt>zext (CST to TYPE)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2678 <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]2679 smaller than the bit size of TYPE. Both types must be integers.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2680
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2681 <dt><b><tt>sext (CST to TYPE)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2682 <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]2683 smaller than the bit size of TYPE. Both types must be integers.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2684
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2685 <dt><b><tt>fptrunc (CST to TYPE)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2686 <dd>Truncate a floating point constant to another floating point type. The
2687 size of CST must be larger than the size of TYPE. Both types must be
2688 floating point.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2689
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2690 <dt><b><tt>fpext (CST to TYPE)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2691 <dd>Floating point extend a constant to another type. The size of CST must be
2692 smaller or equal to the size of TYPE. Both types must be floating
2693 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>fptoui (CST to TYPE)</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2696 <dd>Convert a floating point constant to the corresponding unsigned integer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2697 constant. TYPE must be a scalar or vector integer type. CST must be of
2698 scalar or vector floating point type. Both CST and TYPE must be scalars,
2699 or vectors of the same number of elements. If the value won't fit in the
2700 integer type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2701
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2702 <dt><b><tt>fptosi (CST to TYPE)</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2703 <dd>Convert a floating point constant to the corresponding signed integer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2704 constant. TYPE must be a scalar or vector integer type. CST must be of
2705 scalar or vector floating point type. Both CST and TYPE must be scalars,
2706 or vectors of the same number of elements. If the value won't fit in the
2707 integer type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2708
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2709 <dt><b><tt>uitofp (CST to TYPE)</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2710 <dd>Convert an unsigned integer constant to the corresponding floating point
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2711 constant. TYPE must be a scalar or vector floating point type. CST must be
2712 of scalar or vector integer type. Both CST and TYPE must be scalars, or
2713 vectors of the same number of elements. If the value won't fit in the
2714 floating point type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2715
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2716 <dt><b><tt>sitofp (CST to TYPE)</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2717 <dd>Convert a signed integer constant to the corresponding floating point
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2718 constant. TYPE must be a scalar or vector floating point type. CST must be
2719 of scalar or vector integer type. Both CST and TYPE must be scalars, or
2720 vectors of the same number of elements. If the value won't fit in the
2721 floating point type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2722
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2723 <dt><b><tt>ptrtoint (CST to TYPE)</tt></b></dt>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]2724 <dd>Convert a pointer typed constant to the corresponding integer constant
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2725 <tt>TYPE</tt> must be an integer type. <tt>CST</tt> must be of pointer
2726 type. The <tt>CST</tt> value is zero extended, truncated, or unchanged to
2727 make it fit in <tt>TYPE</tt>.</dd>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]2728
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2729 <dt><b><tt>inttoptr (CST to TYPE)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2730 <dd>Convert a integer constant to a pointer constant. TYPE must be a pointer
2731 type. CST must be of integer type. The CST value is zero extended,
2732 truncated, or unchanged to make it fit in a pointer size. This one is
2733 <i>really</i> dangerous!</dd>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]2734
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2735 <dt><b><tt>bitcast (CST to TYPE)</tt></b></dt>
Chris Lattner03bbad62009-02-28 18:27:03 +0000[diff] [blame]2736 <dd>Convert a constant, CST, to another TYPE. The constraints of the operands
2737 are the same as those for the <a href="#i_bitcast">bitcast
2738 instruction</a>.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2739
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2740 <dt><b><tt>getelementptr (CSTPTR, IDX0, IDX1, ...)</tt></b></dt>
2741 <dt><b><tt>getelementptr inbounds (CSTPTR, IDX0, IDX1, ...)</tt></b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2742 <dd>Perform the <a href="#i_getelementptr">getelementptr operation</a> on
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2743 constants. As with the <a href="#i_getelementptr">getelementptr</a>
2744 instruction, the index list may have zero or more indexes, which are
2745 required to make sense for the type of "CSTPTR".</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2746
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2747 <dt><b><tt>select (COND, VAL1, VAL2)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2748 <dd>Perform the <a href="#i_select">select operation</a> on constants.</dd>
Reid Spencer01c42592006-12-04 19:23:19 +0000[diff] [blame]2749
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2750 <dt><b><tt>icmp COND (VAL1, VAL2)</tt></b></dt>
Reid Spencer01c42592006-12-04 19:23:19 +0000[diff] [blame]2751 <dd>Performs the <a href="#i_icmp">icmp operation</a> on constants.</dd>
2752
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2753 <dt><b><tt>fcmp COND (VAL1, VAL2)</tt></b></dt>
Reid Spencer01c42592006-12-04 19:23:19 +0000[diff] [blame]2754 <dd>Performs the <a href="#i_fcmp">fcmp operation</a> on constants.</dd>
Robert Bocchino9fbe1452006-01-10 19:31:34 +0000[diff] [blame]2755
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2756 <dt><b><tt>extractelement (VAL, IDX)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2757 <dd>Perform the <a href="#i_extractelement">extractelement operation</a> on
2758 constants.</dd>
Robert Bocchino9fbe1452006-01-10 19:31:34 +0000[diff] [blame]2759
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2760 <dt><b><tt>insertelement (VAL, ELT, IDX)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2761 <dd>Perform the <a href="#i_insertelement">insertelement operation</a> on
2762 constants.</dd>
Chris Lattnerc1989542006-04-08 00:13:41 +0000[diff] [blame]2763
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2764 <dt><b><tt>shufflevector (VEC1, VEC2, IDXMASK)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2765 <dd>Perform the <a href="#i_shufflevector">shufflevector operation</a> on
2766 constants.</dd>
Chris Lattnerc1989542006-04-08 00:13:41 +0000[diff] [blame]2767
Nick Lewycky9e130ce2010-05-29 06:44:15 +0000[diff] [blame]2768 <dt><b><tt>extractvalue (VAL, IDX0, IDX1, ...)</tt></b></dt>
2769 <dd>Perform the <a href="#i_extractvalue">extractvalue operation</a> on
2770 constants. The index list is interpreted in a similar manner as indices in
2771 a '<a href="#i_getelementptr">getelementptr</a>' operation. At least one
2772 index value must be specified.</dd>
2773
2774 <dt><b><tt>insertvalue (VAL, ELT, IDX0, IDX1, ...)</tt></b></dt>
2775 <dd>Perform the <a href="#i_insertvalue">insertvalue operation</a> on
2776 constants. The index list is interpreted in a similar manner as indices in
2777 a '<a href="#i_getelementptr">getelementptr</a>' operation. At least one
2778 index value must be specified.</dd>
2779
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2780 <dt><b><tt>OPCODE (LHS, RHS)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2781 <dd>Perform the specified operation of the LHS and RHS constants. OPCODE may
2782 be any of the <a href="#binaryops">binary</a>
2783 or <a href="#bitwiseops">bitwise binary</a> operations. The constraints
2784 on operands are the same as those for the corresponding instruction
2785 (e.g. no bitwise operations on floating point values are allowed).</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2786</dl>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2787
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2788</div>
Chris Lattner9ee5d222004-03-08 16:49:10 +0000[diff] [blame]2789
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2790</div>
2791
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2792<!-- *********************************************************************** -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2793<h2><a name="othervalues">Other Values</a></h2>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2794<!-- *********************************************************************** -->
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2795<div>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2796<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2797<h3>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2798<a name="inlineasm">Inline Assembler Expressions</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2799</h3>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2800
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2801<div>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2802
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2803<p>LLVM supports inline assembler expressions (as opposed
2804 to <a href="#moduleasm"> Module-Level Inline Assembly</a>) through the use of
2805 a special value. This value represents the inline assembler as a string
2806 (containing the instructions to emit), a list of operand constraints (stored
Dale Johannesen09fed252009-10-13 21:56:55 +0000[diff] [blame]2807 as a string), a flag that indicates whether or not the inline asm
Dale Johannesen8ba2d5b2009-10-21 23:28:00 +0000[diff] [blame]2808 expression has side effects, and a flag indicating whether the function
2809 containing the asm needs to align its stack conservatively. An example
2810 inline assembler expression is:</p>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2811
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2812<pre class="doc_code">
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2813i32 (i32) asm "bswap $0", "=r,r"
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2814</pre>
2815
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2816<p>Inline assembler expressions may <b>only</b> be used as the callee operand of
2817 a <a href="#i_call"><tt>call</tt> instruction</a>. Thus, typically we
2818 have:</p>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2819
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2820<pre class="doc_code">
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2821%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]2822</pre>
2823
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2824<p>Inline asms with side effects not visible in the constraint list must be
2825 marked as having side effects. This is done through the use of the
2826 '<tt>sideeffect</tt>' keyword, like so:</p>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2827
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2828<pre class="doc_code">
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2829call void asm sideeffect "eieio", ""()
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2830</pre>
2831
Dale Johannesen8ba2d5b2009-10-21 23:28:00 +0000[diff] [blame]2832<p>In some cases inline asms will contain code that will not work unless the
2833 stack is aligned in some way, such as calls or SSE instructions on x86,
2834 yet will not contain code that does that alignment within the asm.
2835 The compiler should make conservative assumptions about what the asm might
2836 contain and should generate its usual stack alignment code in the prologue
2837 if the '<tt>alignstack</tt>' keyword is present:</p>
Dale Johannesen09fed252009-10-13 21:56:55 +0000[diff] [blame]2838
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2839<pre class="doc_code">
Dale Johannesen8ba2d5b2009-10-21 23:28:00 +0000[diff] [blame]2840call void asm alignstack "eieio", ""()
Dale Johannesen09fed252009-10-13 21:56:55 +0000[diff] [blame]2841</pre>
Dale Johannesen09fed252009-10-13 21:56:55 +0000[diff] [blame]2842
2843<p>If both keywords appear the '<tt>sideeffect</tt>' keyword must come
2844 first.</p>
2845
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2846<p>TODO: The format of the asm and constraints string still need to be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2847 documented here. Constraints on what can be done (e.g. duplication, moving,
2848 etc need to be documented). This is probably best done by reference to
2849 another document that covers inline asm from a holistic perspective.</p>
Chris Lattnercf9a4152010-04-07 05:38:05 +0000[diff] [blame]2850
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2851<h4>
Chris Lattnercf9a4152010-04-07 05:38:05 +0000[diff] [blame]2852<a name="inlineasm_md">Inline Asm Metadata</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2853</h4>
Chris Lattnercf9a4152010-04-07 05:38:05 +0000[diff] [blame]2854
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2855<div>
Chris Lattnercf9a4152010-04-07 05:38:05 +0000[diff] [blame]2856
2857<p>The call instructions that wrap inline asm nodes may have a "!srcloc" MDNode
Chris Lattnerce1b9ad2010-11-17 08:20:42 +0000[diff] [blame]2858 attached to it that contains a list of constant integers. If present, the
2859 code generator will use the integer as the location cookie value when report
Chris Lattnercf9a4152010-04-07 05:38:05 +0000[diff] [blame]2860 errors through the LLVMContext error reporting mechanisms. This allows a
Dan Gohman1c70c002010-04-28 00:36:01 +0000[diff] [blame]2861 front-end to correlate backend errors that occur with inline asm back to the
Chris Lattnercf9a4152010-04-07 05:38:05 +0000[diff] [blame]2862 source code that produced it. For example:</p>
2863
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2864<pre class="doc_code">
Chris Lattnercf9a4152010-04-07 05:38:05 +0000[diff] [blame]2865call void asm sideeffect "something bad", ""()<b>, !srcloc !42</b>
2866...
2867!42 = !{ i32 1234567 }
2868</pre>
Chris Lattnercf9a4152010-04-07 05:38:05 +0000[diff] [blame]2869
2870<p>It is up to the front-end to make sense of the magic numbers it places in the
Chris Lattnerce1b9ad2010-11-17 08:20:42 +0000[diff] [blame]2871 IR. If the MDNode contains multiple constants, the code generator will use
2872 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]2873
2874</div>
2875
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2876</div>
2877
Chris Lattnere6a5ddd2010-01-15 21:50:19 +0000[diff] [blame]2878<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2879<h3>
2880 <a name="metadata">Metadata Nodes and Metadata Strings</a>
2881</h3>
Chris Lattnere6a5ddd2010-01-15 21:50:19 +0000[diff] [blame]2882
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2883<div>
Chris Lattnere6a5ddd2010-01-15 21:50:19 +0000[diff] [blame]2884
2885<p>LLVM IR allows metadata to be attached to instructions in the program that
2886 can convey extra information about the code to the optimizers and code
2887 generator. One example application of metadata is source-level debug
2888 information. There are two metadata primitives: strings and nodes. All
2889 metadata has the <tt>metadata</tt> type and is identified in syntax by a
2890 preceding exclamation point ('<tt>!</tt>').</p>
2891
2892<p>A metadata string is a string surrounded by double quotes. It can contain
2893 any character by escaping non-printable characters with "\xx" where "xx" is
2894 the two digit hex code. For example: "<tt>!"test\00"</tt>".</p>
2895
2896<p>Metadata nodes are represented with notation similar to structure constants
2897 (a comma separated list of elements, surrounded by braces and preceded by an
2898 exclamation point). For example: "<tt>!{ metadata !"test\00", i32
2899 10}</tt>". Metadata nodes can have any values as their operand.</p>
2900
2901<p>A <a href="#namedmetadatastructure">named metadata</a> is a collection of
2902 metadata nodes, which can be looked up in the module symbol table. For
2903 example: "<tt>!foo = metadata !{!4, !3}</tt>".
2904
Devang Patele1d50cd2010-03-04 23:44:48 +0000[diff] [blame]2905<p>Metadata can be used as function arguments. Here <tt>llvm.dbg.value</tt>
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2906 function is using two metadata arguments.</p>
Devang Patele1d50cd2010-03-04 23:44:48 +0000[diff] [blame]2907
Bill Wendling9ff5de92011-03-02 02:17:11 +0000[diff] [blame]2908<div class="doc_code">
2909<pre>
2910call void @llvm.dbg.value(metadata !24, i64 0, metadata !25)
2911</pre>
2912</div>
Devang Patele1d50cd2010-03-04 23:44:48 +0000[diff] [blame]2913
2914<p>Metadata can be attached with an instruction. Here metadata <tt>!21</tt> is
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2915 attached with <tt>add</tt> instruction using <tt>!dbg</tt> identifier.</p>
Devang Patele1d50cd2010-03-04 23:44:48 +0000[diff] [blame]2916
Bill Wendling9ff5de92011-03-02 02:17:11 +0000[diff] [blame]2917<div class="doc_code">
2918<pre>
2919%indvar.next = add i64 %indvar, 1, !dbg !21
2920</pre>
2921</div>
2922
Peter Collingbourne249d9532011-10-27 19:19:07 +0000[diff] [blame]2923<p>More information about specific metadata nodes recognized by the optimizers
2924 and code generator is found below.</p>
2925
2926<h4>
2927 <a name="tbaa">'<tt>tbaa</tt>' Metadata</a>
2928</h4>
2929
2930<div>
2931
2932<p>In LLVM IR, memory does not have types, so LLVM's own type system is not
2933 suitable for doing TBAA. Instead, metadata is added to the IR to describe
2934 a type system of a higher level language. This can be used to implement
2935 typical C/C++ TBAA, but it can also be used to implement custom alias
2936 analysis behavior for other languages.</p>
2937
2938<p>The current metadata format is very simple. TBAA metadata nodes have up to
2939 three fields, e.g.:</p>
2940
2941<div class="doc_code">
2942<pre>
2943!0 = metadata !{ metadata !"an example type tree" }
2944!1 = metadata !{ metadata !"int", metadata !0 }
2945!2 = metadata !{ metadata !"float", metadata !0 }
2946!3 = metadata !{ metadata !"const float", metadata !2, i64 1 }
2947</pre>
2948</div>
2949
2950<p>The first field is an identity field. It can be any value, usually
2951 a metadata string, which uniquely identifies the type. The most important
2952 name in the tree is the name of the root node. Two trees with
2953 different root node names are entirely disjoint, even if they
2954 have leaves with common names.</p>
2955
2956<p>The second field identifies the type's parent node in the tree, or
2957 is null or omitted for a root node. A type is considered to alias
2958 all of its descendants and all of its ancestors in the tree. Also,
2959 a type is considered to alias all types in other trees, so that
2960 bitcode produced from multiple front-ends is handled conservatively.</p>
2961
2962<p>If the third field is present, it's an integer which if equal to 1
2963 indicates that the type is "constant" (meaning
2964 <tt>pointsToConstantMemory</tt> should return true; see
2965 <a href="AliasAnalysis.html#OtherItfs">other useful
2966 <tt>AliasAnalysis</tt> methods</a>).</p>
2967
2968</div>
2969
Peter Collingbourne999f90b2011-10-27 19:19:14 +0000[diff] [blame]2970<h4>
2971 <a name="fpaccuracy">'<tt>fpaccuracy</tt>' Metadata</a>
2972</h4>
2973
2974<div>
2975
2976<p><tt>fpaccuracy</tt> metadata may be attached to any instruction of floating
2977 point type. It expresses the maximum relative error of the result of
2978 that instruction, in ULPs. ULP is defined as follows:</p>
2979
2980<blockquote><p>
2981If x is a real number that lies between two finite consecutive floating-point
2982numbers a and b, without being equal to one of them, then ulp(x) = |b - a|,
2983otherwise ulp(x) is the distance between the two non-equal finite
2984floating-point numbers nearest x. Moreover, ulp(NaN) is NaN.
2985</p></blockquote>
2986
2987<p>The maximum relative error may be any rational number. The metadata node
2988 shall consist of a pair of unsigned integers respectively representing
2989 the numerator and denominator. For example, 2.5 ULP:</p>
2990
2991<div class="doc_code">
2992<pre>
2993!0 = metadata !{ i32 5, i32 2 }
2994</pre>
2995</div>
2996
2997</div>
2998
Chris Lattnere6a5ddd2010-01-15 21:50:19 +0000[diff] [blame]2999</div>
3000
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3001</div>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3002
3003<!-- *********************************************************************** -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3004<h2>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3005 <a name="intrinsic_globals">Intrinsic Global Variables</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3006</h2>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3007<!-- *********************************************************************** -->
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3008<div>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3009<p>LLVM has a number of "magic" global variables that contain data that affect
3010code generation or other IR semantics. These are documented here. All globals
Chris Lattner401e10c2009-07-20 06:14:25 +0000[diff] [blame]3011of this sort should have a section specified as "<tt>llvm.metadata</tt>". This
3012section and all globals that start with "<tt>llvm.</tt>" are reserved for use
3013by LLVM.</p>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3014
3015<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3016<h3>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3017<a name="intg_used">The '<tt>llvm.used</tt>' Global Variable</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3018</h3>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3019
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3020<div>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3021
3022<p>The <tt>@llvm.used</tt> global is an array with i8* element type which has <a
3023href="#linkage_appending">appending linkage</a>. This array contains a list of
3024pointers to global variables and functions which may optionally have a pointer
3025cast formed of bitcast or getelementptr. For example, a legal use of it is:</p>
3026
3027<pre>
3028 @X = global i8 4
3029 @Y = global i32 123
3030
3031 @llvm.used = appending global [2 x i8*] [
3032 i8* @X,
3033 i8* bitcast (i32* @Y to i8*)
3034 ], section "llvm.metadata"
3035</pre>
3036
3037<p>If a global variable appears in the <tt>@llvm.used</tt> list, then the
3038compiler, assembler, and linker are required to treat the symbol as if there is
3039a reference to the global that it cannot see. For example, if a variable has
3040internal linkage and no references other than that from the <tt>@llvm.used</tt>
3041list, it cannot be deleted. This is commonly used to represent references from
3042inline asms and other things the compiler cannot "see", and corresponds to
3043"attribute((used))" in GNU C.</p>
3044
3045<p>On some targets, the code generator must emit a directive to the assembler or
3046object file to prevent the assembler and linker from molesting the symbol.</p>
3047
3048</div>
3049
3050<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3051<h3>
3052 <a name="intg_compiler_used">
3053 The '<tt>llvm.compiler.used</tt>' Global Variable
3054 </a>
3055</h3>
Chris Lattner401e10c2009-07-20 06:14:25 +0000[diff] [blame]3056
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3057<div>
Chris Lattner401e10c2009-07-20 06:14:25 +0000[diff] [blame]3058
3059<p>The <tt>@llvm.compiler.used</tt> directive is the same as the
3060<tt>@llvm.used</tt> directive, except that it only prevents the compiler from
3061touching the symbol. On targets that support it, this allows an intelligent
3062linker to optimize references to the symbol without being impeded as it would be
3063by <tt>@llvm.used</tt>.</p>
3064
3065<p>This is a rare construct that should only be used in rare circumstances, and
3066should not be exposed to source languages.</p>
3067
3068</div>
3069
3070<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3071<h3>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3072<a name="intg_global_ctors">The '<tt>llvm.global_ctors</tt>' Global Variable</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3073</h3>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3074
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3075<div>
David Chisnalle31e9962010-04-30 19:23:49 +0000[diff] [blame]3076<pre>
3077%0 = type { i32, void ()* }
David Chisnall27195a52010-04-30 19:27:35 +0000[diff] [blame]3078@llvm.global_ctors = appending global [1 x %0] [%0 { i32 65535, void ()* @ctor }]
David Chisnalle31e9962010-04-30 19:23:49 +0000[diff] [blame]3079</pre>
3080<p>The <tt>@llvm.global_ctors</tt> array contains a list of constructor functions and associated priorities. The functions referenced by this array will be called in ascending order of priority (i.e. lowest first) when the module is loaded. The order of functions with the same priority is not defined.
3081</p>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3082
3083</div>
3084
3085<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3086<h3>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3087<a name="intg_global_dtors">The '<tt>llvm.global_dtors</tt>' Global Variable</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3088</h3>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3089
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3090<div>
David Chisnalle31e9962010-04-30 19:23:49 +0000[diff] [blame]3091<pre>
3092%0 = type { i32, void ()* }
David Chisnall27195a52010-04-30 19:27:35 +0000[diff] [blame]3093@llvm.global_dtors = appending global [1 x %0] [%0 { i32 65535, void ()* @dtor }]
David Chisnalle31e9962010-04-30 19:23:49 +0000[diff] [blame]3094</pre>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3095
David Chisnalle31e9962010-04-30 19:23:49 +0000[diff] [blame]3096<p>The <tt>@llvm.global_dtors</tt> array contains a list of destructor functions and associated priorities. The functions referenced by this array will be called in descending order of priority (i.e. highest first) when the module is loaded. The order of functions with the same priority is not defined.
3097</p>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3098
3099</div>
3100
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3101</div>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3102
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]3103<!-- *********************************************************************** -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3104<h2><a name="instref">Instruction Reference</a></h2>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3105<!-- *********************************************************************** -->
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]3106
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3107<div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]3108
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3109<p>The LLVM instruction set consists of several different classifications of
3110 instructions: <a href="#terminators">terminator
3111 instructions</a>, <a href="#binaryops">binary instructions</a>,
3112 <a href="#bitwiseops">bitwise binary instructions</a>,
3113 <a href="#memoryops">memory instructions</a>, and
3114 <a href="#otherops">other instructions</a>.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]3115
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3116<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3117<h3>
3118 <a name="terminators">Terminator Instructions</a>
3119</h3>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]3120
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3121<div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]3122
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3123<p>As mentioned <a href="#functionstructure">previously</a>, every basic block
3124 in a program ends with a "Terminator" instruction, which indicates which
3125 block should be executed after the current block is finished. These
3126 terminator instructions typically yield a '<tt>void</tt>' value: they produce
3127 control flow, not values (the one exception being the
3128 '<a href="#i_invoke"><tt>invoke</tt></a>' instruction).</p>
3129
Chris Lattner6445ecb2011-08-02 20:29:13 +0000[diff] [blame]3130<p>The terminator instructions are:
3131 '<a href="#i_ret"><tt>ret</tt></a>',
3132 '<a href="#i_br"><tt>br</tt></a>',
3133 '<a href="#i_switch"><tt>switch</tt></a>',
3134 '<a href="#i_indirectbr"><tt>indirectbr</tt></a>',
3135 '<a href="#i_invoke"><tt>invoke</tt></a>',
3136 '<a href="#i_unwind"><tt>unwind</tt></a>',
3137 '<a href="#i_resume"><tt>resume</tt></a>', and
3138 '<a href="#i_unreachable"><tt>unreachable</tt></a>'.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]3139
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3140<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3141<h4>
3142 <a name="i_ret">'<tt>ret</tt>' Instruction</a>
3143</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3144
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3145<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3146
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3147<h5>Syntax:</h5>
Dan Gohmanb1e6b962008-10-04 19:00:07 +0000[diff] [blame]3148<pre>
3149 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]3150 ret void <i>; Return from void function</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3151</pre>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]3152
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3153<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3154<p>The '<tt>ret</tt>' instruction is used to return control flow (and optionally
3155 a value) from a function back to the caller.</p>
3156
3157<p>There are two forms of the '<tt>ret</tt>' instruction: one that returns a
3158 value and then causes control flow, and one that just causes control flow to
3159 occur.</p>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]3160
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3161<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3162<p>The '<tt>ret</tt>' instruction optionally accepts a single argument, the
3163 return value. The type of the return value must be a
3164 '<a href="#t_firstclass">first class</a>' type.</p>
Dan Gohmanb1e6b962008-10-04 19:00:07 +0000[diff] [blame]3165
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3166<p>A function is not <a href="#wellformed">well formed</a> if it it has a
3167 non-void return type and contains a '<tt>ret</tt>' instruction with no return
3168 value or a return value with a type that does not match its type, or if it
3169 has a void return type and contains a '<tt>ret</tt>' instruction with a
3170 return value.</p>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]3171
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3172<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3173<p>When the '<tt>ret</tt>' instruction is executed, control flow returns back to
3174 the calling function's context. If the caller is a
3175 "<a href="#i_call"><tt>call</tt></a>" instruction, execution continues at the
3176 instruction after the call. If the caller was an
3177 "<a href="#i_invoke"><tt>invoke</tt></a>" instruction, execution continues at
3178 the beginning of the "normal" destination block. If the instruction returns
3179 a value, that value shall set the call or invoke instruction's return
3180 value.</p>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]3181
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3182<h5>Example:</h5>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]3183<pre>
3184 ret i32 5 <i>; Return an integer value of 5</i>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]3185 ret void <i>; Return from a void function</i>
Bill Wendling0a4bbbf2009-02-28 22:12:54 +0000[diff] [blame]3186 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]3187</pre>
Dan Gohmanf3e60bd2009-01-12 23:12:39 +0000[diff] [blame]3188
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3189</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3190<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3191<h4>
3192 <a name="i_br">'<tt>br</tt>' Instruction</a>
3193</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3194
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3195<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3196
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3197<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3198<pre>
Bill Wendlingb3aa4712011-07-26 10:41:15 +0000[diff] [blame]3199 br i1 &lt;cond&gt;, label &lt;iftrue&gt;, label &lt;iffalse&gt;
3200 br label &lt;dest&gt; <i>; Unconditional branch</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3201</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3202
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3203<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3204<p>The '<tt>br</tt>' instruction is used to cause control flow to transfer to a
3205 different basic block in the current function. There are two forms of this
3206 instruction, corresponding to a conditional branch and an unconditional
3207 branch.</p>
3208
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3209<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3210<p>The conditional branch form of the '<tt>br</tt>' instruction takes a single
3211 '<tt>i1</tt>' value and two '<tt>label</tt>' values. The unconditional form
3212 of the '<tt>br</tt>' instruction takes a single '<tt>label</tt>' value as a
3213 target.</p>
3214
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3215<h5>Semantics:</h5>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3216<p>Upon execution of a conditional '<tt>br</tt>' instruction, the '<tt>i1</tt>'
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3217 argument is evaluated. If the value is <tt>true</tt>, control flows to the
3218 '<tt>iftrue</tt>' <tt>label</tt> argument. If "cond" is <tt>false</tt>,
3219 control flows to the '<tt>iffalse</tt>' <tt>label</tt> argument.</p>
3220
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3221<h5>Example:</h5>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]3222<pre>
3223Test:
3224 %cond = <a href="#i_icmp">icmp</a> eq i32 %a, %b
3225 br i1 %cond, label %IfEqual, label %IfUnequal
3226IfEqual:
3227 <a href="#i_ret">ret</a> i32 1
3228IfUnequal:
3229 <a href="#i_ret">ret</a> i32 0
3230</pre>
3231
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3232</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3233
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3234<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3235<h4>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3236 <a name="i_switch">'<tt>switch</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3237</h4>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3238
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3239<div>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3240
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3241<h5>Syntax:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3242<pre>
3243 switch &lt;intty&gt; &lt;value&gt;, label &lt;defaultdest&gt; [ &lt;intty&gt; &lt;val&gt;, label &lt;dest&gt; ... ]
3244</pre>
3245
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3246<h5>Overview:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3247<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]3248 several different places. It is a generalization of the '<tt>br</tt>'
3249 instruction, allowing a branch to occur to one of many possible
3250 destinations.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3251
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3252<h5>Arguments:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3253<p>The '<tt>switch</tt>' instruction uses three parameters: an integer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3254 comparison value '<tt>value</tt>', a default '<tt>label</tt>' destination,
3255 and an array of pairs of comparison value constants and '<tt>label</tt>'s.
3256 The table is not allowed to contain duplicate constant entries.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3257
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3258<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3259<p>The <tt>switch</tt> instruction specifies a table of values and
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3260 destinations. When the '<tt>switch</tt>' instruction is executed, this table
3261 is searched for the given value. If the value is found, control flow is
Benjamin Kramer8040cd32009-10-12 14:46:08 +0000[diff] [blame]3262 transferred to the corresponding destination; otherwise, control flow is
3263 transferred to the default destination.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3264
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3265<h5>Implementation:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3266<p>Depending on properties of the target machine and the particular
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3267 <tt>switch</tt> instruction, this instruction may be code generated in
3268 different ways. For example, it could be generated as a series of chained
3269 conditional branches or with a lookup table.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3270
3271<h5>Example:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3272<pre>
3273 <i>; Emulate a conditional br instruction</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3274 %Val = <a href="#i_zext">zext</a> i1 %value to i32
Dan Gohman2a08c532009-01-04 23:44:43 +0000[diff] [blame]3275 switch i32 %Val, label %truedest [ i32 0, label %falsedest ]
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3276
3277 <i>; Emulate an unconditional br instruction</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3278 switch i32 0, label %dest [ ]
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3279
3280 <i>; Implement a jump table:</i>
Dan Gohman2a08c532009-01-04 23:44:43 +0000[diff] [blame]3281 switch i32 %val, label %otherwise [ i32 0, label %onzero
3282 i32 1, label %onone
3283 i32 2, label %ontwo ]
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3284</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3285
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3286</div>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3287
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]3288
3289<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3290<h4>
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]3291 <a name="i_indirectbr">'<tt>indirectbr</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3292</h4>
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]3293
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3294<div>
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]3295
3296<h5>Syntax:</h5>
3297<pre>
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]3298 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]3299</pre>
3300
3301<h5>Overview:</h5>
3302
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]3303<p>The '<tt>indirectbr</tt>' instruction implements an indirect branch to a label
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]3304 within the current function, whose address is specified by
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]3305 "<tt>address</tt>". Address must be derived from a <a
3306 href="#blockaddress">blockaddress</a> constant.</p>
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]3307
3308<h5>Arguments:</h5>
3309
3310<p>The '<tt>address</tt>' argument is the address of the label to jump to. The
3311 rest of the arguments indicate the full set of possible destinations that the
3312 address may point to. Blocks are allowed to occur multiple times in the
3313 destination list, though this isn't particularly useful.</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3314
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]3315<p>This destination list is required so that dataflow analysis has an accurate
3316 understanding of the CFG.</p>
3317
3318<h5>Semantics:</h5>
3319
3320<p>Control transfers to the block specified in the address argument. All
3321 possible destination blocks must be listed in the label list, otherwise this
3322 instruction has undefined behavior. This implies that jumps to labels
3323 defined in other functions have undefined behavior as well.</p>
3324
3325<h5>Implementation:</h5>
3326
3327<p>This is typically implemented with a jump through a register.</p>
3328
3329<h5>Example:</h5>
3330<pre>
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]3331 indirectbr i8* %Addr, [ label %bb1, label %bb2, label %bb3 ]
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]3332</pre>
3333
3334</div>
3335
3336
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3337<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3338<h4>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3339 <a name="i_invoke">'<tt>invoke</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3340</h4>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3341
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3342<div>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3343
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3344<h5>Syntax:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3345<pre>
Devang Patel307e8ab2008-10-07 17:48:33 +0000[diff] [blame]3346 &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]3347 to label &lt;normal label&gt; unwind label &lt;exception label&gt;
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3348</pre>
3349
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]3350<h5>Overview:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3351<p>The '<tt>invoke</tt>' instruction causes control to transfer to a specified
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3352 function, with the possibility of control flow transfer to either the
3353 '<tt>normal</tt>' label or the '<tt>exception</tt>' label. If the callee
3354 function returns with the "<tt><a href="#i_ret">ret</a></tt>" instruction,
3355 control flow will return to the "normal" label. If the callee (or any
3356 indirect callees) returns with the "<a href="#i_unwind"><tt>unwind</tt></a>"
3357 instruction, control is interrupted and continued at the dynamically nearest
3358 "exception" label.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3359
Bill Wendlingf78faf82011-08-02 21:52:38 +0000[diff] [blame]3360<p>The '<tt>exception</tt>' label is a
3361 <i><a href="ExceptionHandling.html#overview">landing pad</a></i> for the
3362 exception. As such, '<tt>exception</tt>' label is required to have the
3363 "<a href="#i_landingpad"><tt>landingpad</tt></a>" instruction, which contains
3364 the information about about the behavior of the program after unwinding
3365 happens, as its first non-PHI instruction. The restrictions on the
3366 "<tt>landingpad</tt>" instruction's tightly couples it to the
3367 "<tt>invoke</tt>" instruction, so that the important information contained
3368 within the "<tt>landingpad</tt>" instruction can't be lost through normal
3369 code motion.</p>
3370
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3371<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3372<p>This instruction requires several arguments:</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3373
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3374<ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3375 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
3376 convention</a> the call should use. If none is specified, the call
3377 defaults to using C calling conventions.</li>
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]3378
3379 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3380 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
3381 '<tt>inreg</tt>' attributes are valid here.</li>
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]3382
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3383 <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]3384 function value being invoked. In most cases, this is a direct function
3385 invocation, but indirect <tt>invoke</tt>s are just as possible, branching
3386 off an arbitrary pointer to function value.</li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3387
3388 <li>'<tt>function ptr val</tt>': An LLVM value containing a pointer to a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3389 function to be invoked. </li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3390
3391 <li>'<tt>function args</tt>': argument list whose types match the function
Chris Lattner0724fbd2010-03-02 06:36:51 +0000[diff] [blame]3392 signature argument types and parameter attributes. All arguments must be
3393 of <a href="#t_firstclass">first class</a> type. If the function
3394 signature indicates the function accepts a variable number of arguments,
3395 the extra arguments can be specified.</li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3396
3397 <li>'<tt>normal label</tt>': the label reached when the called function
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3398 executes a '<tt><a href="#i_ret">ret</a></tt>' instruction. </li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3399
3400 <li>'<tt>exception label</tt>': the label reached when a callee returns with
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3401 the <a href="#i_unwind"><tt>unwind</tt></a> instruction. </li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3402
Devang Patel307e8ab2008-10-07 17:48:33 +0000[diff] [blame]3403 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3404 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
3405 '<tt>readnone</tt>' attributes are valid here.</li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3406</ol>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3407
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3408<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3409<p>This instruction is designed to operate as a standard
3410 '<tt><a href="#i_call">call</a></tt>' instruction in most regards. The
3411 primary difference is that it establishes an association with a label, which
3412 is used by the runtime library to unwind the stack.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3413
3414<p>This instruction is used in languages with destructors to ensure that proper
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3415 cleanup is performed in the case of either a <tt>longjmp</tt> or a thrown
3416 exception. Additionally, this is important for implementation of
3417 '<tt>catch</tt>' clauses in high-level languages that support them.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3418
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3419<p>For the purposes of the SSA form, the definition of the value returned by the
3420 '<tt>invoke</tt>' instruction is deemed to occur on the edge from the current
3421 block to the "normal" label. If the callee unwinds then no return value is
3422 available.</p>
Dan Gohmanf96a4992009-05-22 21:47:08 +0000[diff] [blame]3423
Chris Lattnerdf7a6802010-01-15 18:08:37 +0000[diff] [blame]3424<p>Note that the code generator does not yet completely support unwind, and
3425that the invoke/unwind semantics are likely to change in future versions.</p>
3426
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3427<h5>Example:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3428<pre>
Nick Lewyckyd703f652008-03-16 07:18:12 +0000[diff] [blame]3429 %retval = invoke i32 @Test(i32 15) to label %Continue
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]3430 unwind label %TestCleanup <i>; {i32}:retval set</i>
Nick Lewyckyd703f652008-03-16 07:18:12 +0000[diff] [blame]3431 %retval = invoke <a href="#callingconv">coldcc</a> i32 %Testfnptr(i32 15) to label %Continue
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]3432 unwind label %TestCleanup <i>; {i32}:retval set</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3433</pre>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3434
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3435</div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3436
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]3437<!-- _______________________________________________________________________ -->
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3438
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3439<h4>
3440 <a name="i_unwind">'<tt>unwind</tt>' Instruction</a>
3441</h4>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3442
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3443<div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3444
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]3445<h5>Syntax:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3446<pre>
3447 unwind
3448</pre>
3449
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]3450<h5>Overview:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3451<p>The '<tt>unwind</tt>' instruction unwinds the stack, continuing control flow
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3452 at the first callee in the dynamic call stack which used
3453 an <a href="#i_invoke"><tt>invoke</tt></a> instruction to perform the call.
3454 This is primarily used to implement exception handling.</p>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3455
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]3456<h5>Semantics:</h5>
Chris Lattner72ed2002008-04-19 21:01:16 +0000[diff] [blame]3457<p>The '<tt>unwind</tt>' instruction causes execution of the current function to
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3458 immediately halt. The dynamic call stack is then searched for the
3459 first <a href="#i_invoke"><tt>invoke</tt></a> instruction on the call stack.
3460 Once found, execution continues at the "exceptional" destination block
3461 specified by the <tt>invoke</tt> instruction. If there is no <tt>invoke</tt>
3462 instruction in the dynamic call chain, undefined behavior results.</p>
3463
Chris Lattnerdf7a6802010-01-15 18:08:37 +0000[diff] [blame]3464<p>Note that the code generator does not yet completely support unwind, and
3465that the invoke/unwind semantics are likely to change in future versions.</p>
3466
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3467</div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3468
Bill Wendlingdccc03b2011-07-31 06:30:59 +0000[diff] [blame]3469 <!-- _______________________________________________________________________ -->
3470
3471<h4>
3472 <a name="i_resume">'<tt>resume</tt>' Instruction</a>
3473</h4>
3474
3475<div>
3476
3477<h5>Syntax:</h5>
3478<pre>
3479 resume &lt;type&gt; &lt;value&gt;
3480</pre>
3481
3482<h5>Overview:</h5>
3483<p>The '<tt>resume</tt>' instruction is a terminator instruction that has no
3484 successors.</p>
3485
3486<h5>Arguments:</h5>
Bill Wendlingf78faf82011-08-02 21:52:38 +0000[diff] [blame]3487<p>The '<tt>resume</tt>' instruction requires one argument, which must have the
Bill Wendlinge4ad50b2011-08-03 18:37:32 +0000[diff] [blame]3488 same type as the result of any '<tt>landingpad</tt>' instruction in the same
3489 function.</p>
Bill Wendlingdccc03b2011-07-31 06:30:59 +0000[diff] [blame]3490
3491<h5>Semantics:</h5>
3492<p>The '<tt>resume</tt>' instruction resumes propagation of an existing
3493 (in-flight) exception whose unwinding was interrupted with
Bill Wendlingf78faf82011-08-02 21:52:38 +0000[diff] [blame]3494 a <a href="#i_landingpad"><tt>landingpad</tt></a> instruction.</p>
Bill Wendlingdccc03b2011-07-31 06:30:59 +0000[diff] [blame]3495
3496<h5>Example:</h5>
3497<pre>
Bill Wendlingf78faf82011-08-02 21:52:38 +0000[diff] [blame]3498 resume { i8*, i32 } %exn
Bill Wendlingdccc03b2011-07-31 06:30:59 +0000[diff] [blame]3499</pre>
3500
3501</div>
3502
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3503<!-- _______________________________________________________________________ -->
3504
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3505<h4>
3506 <a name="i_unreachable">'<tt>unreachable</tt>' Instruction</a>
3507</h4>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3508
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3509<div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3510
3511<h5>Syntax:</h5>
3512<pre>
3513 unreachable
3514</pre>
3515
3516<h5>Overview:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3517<p>The '<tt>unreachable</tt>' instruction has no defined semantics. This
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3518 instruction is used to inform the optimizer that a particular portion of the
3519 code is not reachable. This can be used to indicate that the code after a
3520 no-return function cannot be reached, and other facts.</p>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3521
3522<h5>Semantics:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3523<p>The '<tt>unreachable</tt>' instruction has no defined semantics.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3524
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3525</div>
3526
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3527</div>
3528
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3529<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3530<h3>
3531 <a name="binaryops">Binary Operations</a>
3532</h3>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3533
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3534<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3535
3536<p>Binary operators are used to do most of the computation in a program. They
3537 require two operands of the same type, execute an operation on them, and
3538 produce a single value. The operands might represent multiple data, as is
3539 the case with the <a href="#t_vector">vector</a> data type. The result value
3540 has the same type as its operands.</p>
3541
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3542<p>There are several different binary operators:</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3543
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3544<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3545<h4>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3546 <a name="i_add">'<tt>add</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3547</h4>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3548
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3549<div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3550
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3551<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3552<pre>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3553 &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]3554 &lt;result&gt; = add nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3555 &lt;result&gt; = add nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3556 &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]3557</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3558
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3559<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3560<p>The '<tt>add</tt>' instruction returns the sum of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3561
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3562<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3563<p>The two arguments to the '<tt>add</tt>' instruction must
3564 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3565 integer values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3566
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3567<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3568<p>The value produced is the integer sum of the two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3569
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3570<p>If the sum has unsigned overflow, the result returned is the mathematical
3571 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]3572
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3573<p>Because LLVM integers use a two's complement representation, this instruction
3574 is appropriate for both signed and unsigned integers.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3575
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]3576<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3577 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3578 <tt>nsw</tt> keywords are present, the result value of the <tt>add</tt>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]3579 is a <a href="#trapvalues">trap value</a> if unsigned and/or signed overflow,
3580 respectively, occurs.</p>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3581
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3582<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3583<pre>
3584 &lt;result&gt; = add i32 4, %var <i>; yields {i32}:result = 4 + %var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3585</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3586
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3587</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3588
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3589<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3590<h4>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3591 <a name="i_fadd">'<tt>fadd</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3592</h4>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3593
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3594<div>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3595
3596<h5>Syntax:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3597<pre>
3598 &lt;result&gt; = fadd &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3599</pre>
3600
3601<h5>Overview:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3602<p>The '<tt>fadd</tt>' instruction returns the sum of its two operands.</p>
3603
3604<h5>Arguments:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3605<p>The two arguments to the '<tt>fadd</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3606 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3607 floating point values. Both arguments must have identical types.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3608
3609<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3610<p>The value produced is the floating point sum of the two operands.</p>
3611
3612<h5>Example:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3613<pre>
3614 &lt;result&gt; = fadd float 4.0, %var <i>; yields {float}:result = 4.0 + %var</i>
3615</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3616
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3617</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3618
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3619<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3620<h4>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3621 <a name="i_sub">'<tt>sub</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3622</h4>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3623
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3624<div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3625
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3626<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3627<pre>
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]3628 &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]3629 &lt;result&gt; = sub nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3630 &lt;result&gt; = sub nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3631 &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]3632</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3633
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3634<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3635<p>The '<tt>sub</tt>' instruction returns the difference of its two
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3636 operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3637
3638<p>Note that the '<tt>sub</tt>' instruction is used to represent the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3639 '<tt>neg</tt>' instruction present in most other intermediate
3640 representations.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3641
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3642<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3643<p>The two arguments to the '<tt>sub</tt>' instruction must
3644 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3645 integer values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3646
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3647<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3648<p>The value produced is the integer difference of the two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3649
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3650<p>If the difference has unsigned overflow, the result returned is the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3651 mathematical result modulo 2<sup>n</sup>, where n is the bit width of the
3652 result.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3653
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3654<p>Because LLVM integers use a two's complement representation, this instruction
3655 is appropriate for both signed and unsigned integers.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3656
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]3657<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3658 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3659 <tt>nsw</tt> keywords are present, the result value of the <tt>sub</tt>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]3660 is a <a href="#trapvalues">trap value</a> if unsigned and/or signed overflow,
3661 respectively, occurs.</p>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3662
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3663<h5>Example:</h5>
Bill Wendlingaac388b2007-05-29 09:42:13 +0000[diff] [blame]3664<pre>
3665 &lt;result&gt; = sub i32 4, %var <i>; yields {i32}:result = 4 - %var</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3666 &lt;result&gt; = sub i32 0, %val <i>; yields {i32}:result = -%var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3667</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3668
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3669</div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3670
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3671<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3672<h4>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3673 <a name="i_fsub">'<tt>fsub</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3674</h4>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3675
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3676<div>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3677
3678<h5>Syntax:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3679<pre>
3680 &lt;result&gt; = fsub &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3681</pre>
3682
3683<h5>Overview:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3684<p>The '<tt>fsub</tt>' instruction returns the difference of its two
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3685 operands.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3686
3687<p>Note that the '<tt>fsub</tt>' instruction is used to represent the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3688 '<tt>fneg</tt>' instruction present in most other intermediate
3689 representations.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3690
3691<h5>Arguments:</h5>
Bill Wendlingd9fe2982009-07-20 02:32:41 +0000[diff] [blame]3692<p>The two arguments to the '<tt>fsub</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3693 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3694 floating point values. Both arguments must have identical types.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3695
3696<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3697<p>The value produced is the floating point difference of the two operands.</p>
3698
3699<h5>Example:</h5>
3700<pre>
3701 &lt;result&gt; = fsub float 4.0, %var <i>; yields {float}:result = 4.0 - %var</i>
3702 &lt;result&gt; = fsub float -0.0, %val <i>; yields {float}:result = -%var</i>
3703</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3704
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3705</div>
3706
3707<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3708<h4>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3709 <a name="i_mul">'<tt>mul</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3710</h4>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3711
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +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<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3715<pre>
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]3716 &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]3717 &lt;result&gt; = mul nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3718 &lt;result&gt; = mul nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3719 &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]3720</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3721
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3722<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3723<p>The '<tt>mul</tt>' instruction returns the product of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3724
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3725<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3726<p>The two arguments to the '<tt>mul</tt>' instruction must
3727 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3728 integer values. Both arguments must have identical types.</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3729
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3730<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3731<p>The value produced is the integer product of the two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3732
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3733<p>If the result of the multiplication has unsigned overflow, the result
3734 returned is the mathematical result modulo 2<sup>n</sup>, where n is the bit
3735 width of the result.</p>
3736
3737<p>Because LLVM integers use a two's complement representation, and the result
3738 is the same width as the operands, this instruction returns the correct
3739 result for both signed and unsigned integers. If a full product
3740 (e.g. <tt>i32</tt>x<tt>i32</tt>-><tt>i64</tt>) is needed, the operands should
3741 be sign-extended or zero-extended as appropriate to the width of the full
3742 product.</p>
3743
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]3744<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3745 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3746 <tt>nsw</tt> keywords are present, the result value of the <tt>mul</tt>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]3747 is a <a href="#trapvalues">trap value</a> if unsigned and/or signed overflow,
3748 respectively, occurs.</p>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3749
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3750<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3751<pre>
3752 &lt;result&gt; = mul i32 4, %var <i>; yields {i32}:result = 4 * %var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3753</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3754
Misha Brukman9d0919f2003-11-08 01:05:38 +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<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3758<h4>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3759 <a name="i_fmul">'<tt>fmul</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3760</h4>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3761
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3762<div>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3763
3764<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3765<pre>
3766 &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]3767</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3768
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3769<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3770<p>The '<tt>fmul</tt>' instruction returns the product of its two operands.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3771
3772<h5>Arguments:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3773<p>The two arguments to the '<tt>fmul</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3774 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3775 floating point values. Both arguments must have identical types.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3776
3777<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3778<p>The value produced is the floating point product of the two operands.</p>
3779
3780<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3781<pre>
3782 &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]3783</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3784
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3785</div>
3786
3787<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3788<h4>
3789 <a name="i_udiv">'<tt>udiv</tt>' Instruction</a>
3790</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3791
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3792<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3793
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3794<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3795<pre>
Chris Lattner35bda892011-02-06 21:44:57 +0000[diff] [blame]3796 &lt;result&gt; = udiv &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3797 &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]3798</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3799
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3800<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3801<p>The '<tt>udiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3802
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3803<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3804<p>The two arguments to the '<tt>udiv</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3805 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3806 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3807
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3808<h5>Semantics:</h5>
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3809<p>The value produced is the unsigned integer quotient of the two operands.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3810
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3811<p>Note that unsigned integer division and signed integer division are distinct
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3812 operations; for signed integer division, use '<tt>sdiv</tt>'.</p>
3813
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3814<p>Division by zero leads to undefined behavior.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3815
Chris Lattner35bda892011-02-06 21:44:57 +0000[diff] [blame]3816<p>If the <tt>exact</tt> keyword is present, the result value of the
3817 <tt>udiv</tt> is a <a href="#trapvalues">trap value</a> if %op1 is not a
3818 multiple of %op2 (as such, "((a udiv exact b) mul b) == a").</p>
3819
3820
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3821<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3822<pre>
3823 &lt;result&gt; = udiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3824</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3825
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3826</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3827
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3828<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3829<h4>
3830 <a name="i_sdiv">'<tt>sdiv</tt>' Instruction</a>
3831</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3832
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3833<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3834
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3835<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3836<pre>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3837 &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]3838 &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]3839</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3840
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3841<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3842<p>The '<tt>sdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3843
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3844<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3845<p>The two arguments to the '<tt>sdiv</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3846 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3847 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3848
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3849<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3850<p>The value produced is the signed integer quotient of the two operands rounded
3851 towards zero.</p>
3852
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3853<p>Note that signed integer division and unsigned integer division are distinct
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3854 operations; for unsigned integer division, use '<tt>udiv</tt>'.</p>
3855
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3856<p>Division by zero leads to undefined behavior. Overflow also leads to
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3857 undefined behavior; this is a rare case, but can occur, for example, by doing
3858 a 32-bit division of -2147483648 by -1.</p>
3859
Dan Gohman9c5beed2009-07-22 00:04:19 +0000[diff] [blame]3860<p>If the <tt>exact</tt> keyword is present, the result value of the
Dan Gohman27ef9972010-04-23 15:23:32 +0000[diff] [blame]3861 <tt>sdiv</tt> is a <a href="#trapvalues">trap value</a> if the result would
Dan Gohman38da9272010-07-11 00:08:34 +0000[diff] [blame]3862 be rounded.</p>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]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; = sdiv 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_fdiv">'<tt>fdiv</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
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3878<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3879<pre>
Gabor Greiffb224a22008-08-07 21:46:00 +0000[diff] [blame]3880 &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]3881</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3882
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3883<h5>Overview:</h5>
3884<p>The '<tt>fdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3885
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3886<h5>Arguments:</h5>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]3887<p>The two arguments to the '<tt>fdiv</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3888 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3889 floating point values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3890
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3891<h5>Semantics:</h5>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3892<p>The value produced is the floating point quotient of the two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3893
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3894<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3895<pre>
3896 &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]3897</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3898
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3899</div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3900
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3901<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3902<h4>
3903 <a name="i_urem">'<tt>urem</tt>' Instruction</a>
3904</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3905
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3906<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3907
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3908<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3909<pre>
3910 &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]3911</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3912
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3913<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3914<p>The '<tt>urem</tt>' instruction returns the remainder from the unsigned
3915 division of its two arguments.</p>
3916
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3917<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3918<p>The two arguments to the '<tt>urem</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3919 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3920 values. Both arguments must have identical types.</p>
3921
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3922<h5>Semantics:</h5>
3923<p>This instruction returns the unsigned integer <i>remainder</i> of a division.
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3924 This instruction always performs an unsigned division to get the
3925 remainder.</p>
3926
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3927<p>Note that unsigned integer remainder and signed integer remainder are
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3928 distinct operations; for signed integer remainder, use '<tt>srem</tt>'.</p>
3929
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3930<p>Taking the remainder of a division by zero leads to undefined behavior.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3931
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3932<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3933<pre>
3934 &lt;result&gt; = urem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3935</pre>
3936
3937</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3938
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3939<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3940<h4>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3941 <a name="i_srem">'<tt>srem</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3942</h4>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3943
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3944<div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3945
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3946<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3947<pre>
Gabor Greiffb224a22008-08-07 21:46:00 +0000[diff] [blame]3948 &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]3949</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3950
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3951<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3952<p>The '<tt>srem</tt>' instruction returns the remainder from the signed
3953 division of its two operands. This instruction can also take
3954 <a href="#t_vector">vector</a> versions of the values in which case the
3955 elements must be integers.</p>
Chris Lattnerc7d3ab32008-01-04 04:33:49 +0000[diff] [blame]3956
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3957<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3958<p>The two arguments to the '<tt>srem</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3959 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3960 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3961
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3962<h5>Semantics:</h5>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3963<p>This instruction returns the <i>remainder</i> of a division (where the result
Duncan Sandsdea3a5e2011-03-07 09:12:24 +0000[diff] [blame]3964 is either zero or has the same sign as the dividend, <tt>op1</tt>), not the
3965 <i>modulo</i> operator (where the result is either zero or has the same sign
3966 as the divisor, <tt>op2</tt>) of a value.
3967 For more information about the difference,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3968 see <a href="http://mathforum.org/dr.math/problems/anne.4.28.99.html">The
3969 Math Forum</a>. For a table of how this is implemented in various languages,
3970 please see <a href="http://en.wikipedia.org/wiki/Modulo_operation">
3971 Wikipedia: modulo operation</a>.</p>
3972
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3973<p>Note that signed integer remainder and unsigned integer remainder are
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3974 distinct operations; for unsigned integer remainder, use '<tt>urem</tt>'.</p>
3975
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3976<p>Taking the remainder of a division by zero leads to undefined behavior.
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3977 Overflow also leads to undefined behavior; this is a rare case, but can
3978 occur, for example, by taking the remainder of a 32-bit division of
3979 -2147483648 by -1. (The remainder doesn't actually overflow, but this rule
3980 lets srem be implemented using instructions that return both the result of
3981 the division and the remainder.)</p>
3982
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3983<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3984<pre>
3985 &lt;result&gt; = srem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3986</pre>
3987
3988</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3989
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3990<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3991<h4>
3992 <a name="i_frem">'<tt>frem</tt>' Instruction</a>
3993</h4>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3994
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3995<div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3996
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3997<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3998<pre>
3999 &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]4000</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4001
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]4002<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4003<p>The '<tt>frem</tt>' instruction returns the remainder from the division of
4004 its two operands.</p>
4005
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]4006<h5>Arguments:</h5>
4007<p>The two arguments to the '<tt>frem</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4008 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
4009 floating point values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4010
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]4011<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4012<p>This instruction returns the <i>remainder</i> of a division. The remainder
4013 has the same sign as the dividend.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4014
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]4015<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4016<pre>
4017 &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]4018</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4019
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4020</div>
Robert Bocchino7b81c752006-02-17 21:18:08 +0000[diff] [blame]4021
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4022</div>
4023
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]4024<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4025<h3>
4026 <a name="bitwiseops">Bitwise Binary Operations</a>
4027</h3>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4028
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4029<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4030
4031<p>Bitwise binary operators are used to do various forms of bit-twiddling in a
4032 program. They are generally very efficient instructions and can commonly be
4033 strength reduced from other instructions. They require two operands of the
4034 same type, execute an operation on them, and produce a single value. The
4035 resulting value is the same type as its operands.</p>
4036
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4037<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4038<h4>
4039 <a name="i_shl">'<tt>shl</tt>' Instruction</a>
4040</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4041
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4042<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4043
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4044<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4045<pre>
Chris Lattnerf067d582011-02-07 16:40:21 +0000[diff] [blame]4046 &lt;result&gt; = shl &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
4047 &lt;result&gt; = shl nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
4048 &lt;result&gt; = shl nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
4049 &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]4050</pre>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]4051
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4052<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4053<p>The '<tt>shl</tt>' instruction returns the first operand shifted to the left
4054 a specified number of bits.</p>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]4055
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4056<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4057<p>Both arguments to the '<tt>shl</tt>' instruction must be the
4058 same <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
4059 integer type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4060
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4061<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4062<p>The value produced is <tt>op1</tt> * 2<sup><tt>op2</tt></sup> mod
4063 2<sup>n</sup>, where <tt>n</tt> is the width of the result. If <tt>op2</tt>
4064 is (statically or dynamically) negative or equal to or larger than the number
4065 of bits in <tt>op1</tt>, the result is undefined. If the arguments are
4066 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
4067 shift amount in <tt>op2</tt>.</p>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]4068
Chris Lattnerf067d582011-02-07 16:40:21 +0000[diff] [blame]4069<p>If the <tt>nuw</tt> keyword is present, then the shift produces a
4070 <a href="#trapvalues">trap value</a> if it shifts out any non-zero bits. If
Chris Lattner66298c12011-02-09 16:44:44 +0000[diff] [blame]4071 the <tt>nsw</tt> keyword is present, then the shift produces a
Chris Lattnerf067d582011-02-07 16:40:21 +0000[diff] [blame]4072 <a href="#trapvalues">trap value</a> if it shifts out any bits that disagree
4073 with the resultant sign bit. As such, NUW/NSW have the same semantics as
4074 they would if the shift were expressed as a mul instruction with the same
4075 nsw/nuw bits in (mul %op1, (shl 1, %op2)).</p>
4076
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4077<h5>Example:</h5>
4078<pre>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4079 &lt;result&gt; = shl i32 4, %var <i>; yields {i32}: 4 &lt;&lt; %var</i>
4080 &lt;result&gt; = shl i32 4, 2 <i>; yields {i32}: 16</i>
4081 &lt;result&gt; = shl i32 1, 10 <i>; yields {i32}: 1024</i>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]4082 &lt;result&gt; = shl i32 1, 32 <i>; undefined</i>
Mon P Wange9f10152008-12-09 05:46:39 +0000[diff] [blame]4083 &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]4084</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4085
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4086</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4087
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4088<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4089<h4>
4090 <a name="i_lshr">'<tt>lshr</tt>' Instruction</a>
4091</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4092
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4093<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4094
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4095<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4096<pre>
Chris Lattnerf067d582011-02-07 16:40:21 +0000[diff] [blame]4097 &lt;result&gt; = lshr &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
4098 &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]4099</pre>
4100
4101<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4102<p>The '<tt>lshr</tt>' instruction (logical shift right) returns the first
4103 operand shifted to the right a specified number of bits with zero fill.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4104
4105<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4106<p>Both arguments to the '<tt>lshr</tt>' instruction must be the same
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4107 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
4108 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4109
4110<h5>Semantics:</h5>
4111<p>This instruction always performs a logical shift right operation. The most
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4112 significant bits of the result will be filled with zero bits after the shift.
4113 If <tt>op2</tt> is (statically or dynamically) equal to or larger than the
4114 number of bits in <tt>op1</tt>, the result is undefined. If the arguments are
4115 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
4116 shift amount in <tt>op2</tt>.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4117
Chris Lattnerf067d582011-02-07 16:40:21 +0000[diff] [blame]4118<p>If the <tt>exact</tt> keyword is present, the result value of the
4119 <tt>lshr</tt> is a <a href="#trapvalues">trap value</a> if any of the bits
4120 shifted out are non-zero.</p>
4121
4122
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4123<h5>Example:</h5>
4124<pre>
4125 &lt;result&gt; = lshr i32 4, 1 <i>; yields {i32}:result = 2</i>
4126 &lt;result&gt; = lshr i32 4, 2 <i>; yields {i32}:result = 1</i>
4127 &lt;result&gt; = lshr i8 4, 3 <i>; yields {i8}:result = 0</i>
4128 &lt;result&gt; = lshr i8 -2, 1 <i>; yields {i8}:result = 0x7FFFFFFF </i>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]4129 &lt;result&gt; = lshr i32 1, 32 <i>; undefined</i>
Mon P Wange9f10152008-12-09 05:46:39 +0000[diff] [blame]4130 &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]4131</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4132
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4133</div>
4134
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]4135<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4136<h4>
4137 <a name="i_ashr">'<tt>ashr</tt>' Instruction</a>
4138</h4>
4139
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4140<div>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4141
4142<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4143<pre>
Chris Lattnerf067d582011-02-07 16:40:21 +0000[diff] [blame]4144 &lt;result&gt; = ashr &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
4145 &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]4146</pre>
4147
4148<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4149<p>The '<tt>ashr</tt>' instruction (arithmetic shift right) returns the first
4150 operand shifted to the right a specified number of bits with sign
4151 extension.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4152
4153<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4154<p>Both arguments to the '<tt>ashr</tt>' instruction must be the same
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4155 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
4156 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4157
4158<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4159<p>This instruction always performs an arithmetic shift right operation, The
4160 most significant bits of the result will be filled with the sign bit
4161 of <tt>op1</tt>. If <tt>op2</tt> is (statically or dynamically) equal to or
4162 larger than the number of bits in <tt>op1</tt>, the result is undefined. If
4163 the arguments are vectors, each vector element of <tt>op1</tt> is shifted by
4164 the corresponding shift amount in <tt>op2</tt>.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4165
Chris Lattnerf067d582011-02-07 16:40:21 +0000[diff] [blame]4166<p>If the <tt>exact</tt> keyword is present, the result value of the
4167 <tt>ashr</tt> is a <a href="#trapvalues">trap value</a> if any of the bits
4168 shifted out are non-zero.</p>
4169
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4170<h5>Example:</h5>
4171<pre>
4172 &lt;result&gt; = ashr i32 4, 1 <i>; yields {i32}:result = 2</i>
4173 &lt;result&gt; = ashr i32 4, 2 <i>; yields {i32}:result = 1</i>
4174 &lt;result&gt; = ashr i8 4, 3 <i>; yields {i8}:result = 0</i>
4175 &lt;result&gt; = ashr i8 -2, 1 <i>; yields {i8}:result = -1</i>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]4176 &lt;result&gt; = ashr i32 1, 32 <i>; undefined</i>
Mon P Wange9f10152008-12-09 05:46:39 +0000[diff] [blame]4177 &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]4178</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4179
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4180</div>
4181
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4182<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4183<h4>
4184 <a name="i_and">'<tt>and</tt>' Instruction</a>
4185</h4>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4186
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4187<div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4188
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4189<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4190<pre>
Gabor Greiffb224a22008-08-07 21:46:00 +0000[diff] [blame]4191 &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]4192</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4193
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4194<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4195<p>The '<tt>and</tt>' instruction returns the bitwise logical and of its two
4196 operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4197
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4198<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4199<p>The two arguments to the '<tt>and</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4200 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
4201 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4202
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4203<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4204<p>The truth table used for the '<tt>and</tt>' instruction is:</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4205
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4206<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4207 <tbody>
4208 <tr>
4209 <td>In0</td>
4210 <td>In1</td>
4211 <td>Out</td>
4212 </tr>
4213 <tr>
4214 <td>0</td>
4215 <td>0</td>
4216 <td>0</td>
4217 </tr>
4218 <tr>
4219 <td>0</td>
4220 <td>1</td>
4221 <td>0</td>
4222 </tr>
4223 <tr>
4224 <td>1</td>
4225 <td>0</td>
4226 <td>0</td>
4227 </tr>
4228 <tr>
4229 <td>1</td>
4230 <td>1</td>
4231 <td>1</td>
4232 </tr>
4233 </tbody>
4234</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4235
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4236<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4237<pre>
4238 &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]4239 &lt;result&gt; = and i32 15, 40 <i>; yields {i32}:result = 8</i>
4240 &lt;result&gt; = and i32 4, 8 <i>; yields {i32}:result = 0</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4241</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4242</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4243<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4244<h4>
4245 <a name="i_or">'<tt>or</tt>' Instruction</a>
4246</h4>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4247
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4248<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4249
4250<h5>Syntax:</h5>
4251<pre>
4252 &lt;result&gt; = or &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
4253</pre>
4254
4255<h5>Overview:</h5>
4256<p>The '<tt>or</tt>' instruction returns the bitwise logical inclusive or of its
4257 two operands.</p>
4258
4259<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4260<p>The two arguments to the '<tt>or</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4261 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
4262 values. Both arguments must have identical types.</p>
4263
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4264<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4265<p>The truth table used for the '<tt>or</tt>' instruction is:</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4266
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4267<table border="1" cellspacing="0" cellpadding="4">
4268 <tbody>
4269 <tr>
4270 <td>In0</td>
4271 <td>In1</td>
4272 <td>Out</td>
4273 </tr>
4274 <tr>
4275 <td>0</td>
4276 <td>0</td>
4277 <td>0</td>
4278 </tr>
4279 <tr>
4280 <td>0</td>
4281 <td>1</td>
4282 <td>1</td>
4283 </tr>
4284 <tr>
4285 <td>1</td>
4286 <td>0</td>
4287 <td>1</td>
4288 </tr>
4289 <tr>
4290 <td>1</td>
4291 <td>1</td>
4292 <td>1</td>
4293 </tr>
4294 </tbody>
4295</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4296
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4297<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4298<pre>
4299 &lt;result&gt; = or i32 4, %var <i>; yields {i32}:result = 4 | %var</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4300 &lt;result&gt; = or i32 15, 40 <i>; yields {i32}:result = 47</i>
4301 &lt;result&gt; = or i32 4, 8 <i>; yields {i32}:result = 12</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4302</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4303
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4304</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4305
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4306<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4307<h4>
4308 <a name="i_xor">'<tt>xor</tt>' Instruction</a>
4309</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4310
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4311<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4312
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4313<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4314<pre>
4315 &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]4316</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4317
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4318<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4319<p>The '<tt>xor</tt>' instruction returns the bitwise logical exclusive or of
4320 its two operands. The <tt>xor</tt> is used to implement the "one's
4321 complement" operation, which is the "~" operator in C.</p>
4322
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4323<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4324<p>The two arguments to the '<tt>xor</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4325 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
4326 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4327
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4328<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4329<p>The truth table used for the '<tt>xor</tt>' instruction is:</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4330
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4331<table border="1" cellspacing="0" cellpadding="4">
4332 <tbody>
4333 <tr>
4334 <td>In0</td>
4335 <td>In1</td>
4336 <td>Out</td>
4337 </tr>
4338 <tr>
4339 <td>0</td>
4340 <td>0</td>
4341 <td>0</td>
4342 </tr>
4343 <tr>
4344 <td>0</td>
4345 <td>1</td>
4346 <td>1</td>
4347 </tr>
4348 <tr>
4349 <td>1</td>
4350 <td>0</td>
4351 <td>1</td>
4352 </tr>
4353 <tr>
4354 <td>1</td>
4355 <td>1</td>
4356 <td>0</td>
4357 </tr>
4358 </tbody>
4359</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4360
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4361<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4362<pre>
4363 &lt;result&gt; = xor i32 4, %var <i>; yields {i32}:result = 4 ^ %var</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4364 &lt;result&gt; = xor i32 15, 40 <i>; yields {i32}:result = 39</i>
4365 &lt;result&gt; = xor i32 4, 8 <i>; yields {i32}:result = 12</i>
4366 &lt;result&gt; = xor i32 %V, -1 <i>; yields {i32}:result = ~%V</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4367</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4368
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4369</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4370
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4371</div>
4372
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4373<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4374<h3>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4375 <a name="vectorops">Vector Operations</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4376</h3>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4377
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4378<div>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4379
4380<p>LLVM supports several instructions to represent vector operations in a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4381 target-independent manner. These instructions cover the element-access and
4382 vector-specific operations needed to process vectors effectively. While LLVM
4383 does directly support these vector operations, many sophisticated algorithms
4384 will want to use target-specific intrinsics to take full advantage of a
4385 specific target.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4386
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4387<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4388<h4>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4389 <a name="i_extractelement">'<tt>extractelement</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4390</h4>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4391
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4392<div>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4393
4394<h5>Syntax:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4395<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4396 &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]4397</pre>
4398
4399<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4400<p>The '<tt>extractelement</tt>' instruction extracts a single scalar element
4401 from a vector at a specified index.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4402
4403
4404<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4405<p>The first operand of an '<tt>extractelement</tt>' instruction is a value
4406 of <a href="#t_vector">vector</a> type. The second operand is an index
4407 indicating the position from which to extract the element. The index may be
4408 a variable.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4409
4410<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4411<p>The result is a scalar of the same type as the element type of
4412 <tt>val</tt>. Its value is the value at position <tt>idx</tt> of
4413 <tt>val</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
4414 results are undefined.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4415
4416<h5>Example:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4417<pre>
Gabor Greifa5b6f452009-10-28 13:14:50 +0000[diff] [blame]4418 &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]4419</pre>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4420
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4421</div>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4422
4423<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4424<h4>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4425 <a name="i_insertelement">'<tt>insertelement</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4426</h4>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4427
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4428<div>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4429
4430<h5>Syntax:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4431<pre>
Dan Gohmanf3480b92008-05-12 23:38:42 +0000[diff] [blame]4432 &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]4433</pre>
4434
4435<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4436<p>The '<tt>insertelement</tt>' instruction inserts a scalar element into a
4437 vector at a specified index.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4438
4439<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4440<p>The first operand of an '<tt>insertelement</tt>' instruction is a value
4441 of <a href="#t_vector">vector</a> type. The second operand is a scalar value
4442 whose type must equal the element type of the first operand. The third
4443 operand is an index indicating the position at which to insert the value.
4444 The index may be a variable.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4445
4446<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4447<p>The result is a vector of the same type as <tt>val</tt>. Its element values
4448 are those of <tt>val</tt> except at position <tt>idx</tt>, where it gets the
4449 value <tt>elt</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
4450 results are undefined.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4451
4452<h5>Example:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4453<pre>
Gabor Greifa5b6f452009-10-28 13:14:50 +0000[diff] [blame]4454 &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]4455</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4456
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4457</div>
4458
4459<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4460<h4>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4461 <a name="i_shufflevector">'<tt>shufflevector</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4462</h4>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4463
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4464<div>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4465
4466<h5>Syntax:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4467<pre>
Mon P Wangaeb06d22008-11-10 04:46:22 +0000[diff] [blame]4468 &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]4469</pre>
4470
4471<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4472<p>The '<tt>shufflevector</tt>' instruction constructs a permutation of elements
4473 from two input vectors, returning a vector with the same element type as the
4474 input and length that is the same as the shuffle mask.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4475
4476<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4477<p>The first two operands of a '<tt>shufflevector</tt>' instruction are vectors
4478 with types that match each other. The third argument is a shuffle mask whose
4479 element type is always 'i32'. The result of the instruction is a vector
4480 whose length is the same as the shuffle mask and whose element type is the
4481 same as the element type of the first two operands.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4482
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4483<p>The shuffle mask operand is required to be a constant vector with either
4484 constant integer or undef values.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4485
4486<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4487<p>The elements of the two input vectors are numbered from left to right across
4488 both of the vectors. The shuffle mask operand specifies, for each element of
4489 the result vector, which element of the two input vectors the result element
4490 gets. The element selector may be undef (meaning "don't care") and the
4491 second operand may be undef if performing a shuffle from only one vector.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4492
4493<h5>Example:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4494<pre>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4495 &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]4496 &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]4497 &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]4498 &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]4499 &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]4500 &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]4501 &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]4502 &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]4503</pre>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4504
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4505</div>
Tanya Lattner09474292006-04-14 19:24:33 +0000[diff] [blame]4506
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4507</div>
4508
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4509<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4510<h3>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4511 <a name="aggregateops">Aggregate Operations</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4512</h3>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4513
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4514<div>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4515
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4516<p>LLVM supports several instructions for working with
4517 <a href="#t_aggregate">aggregate</a> values.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4518
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4519<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4520<h4>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4521 <a name="i_extractvalue">'<tt>extractvalue</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4522</h4>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4523
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4524<div>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4525
4526<h5>Syntax:</h5>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4527<pre>
4528 &lt;result&gt; = extractvalue &lt;aggregate type&gt; &lt;val&gt;, &lt;idx&gt;{, &lt;idx&gt;}*
4529</pre>
4530
4531<h5>Overview:</h5>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4532<p>The '<tt>extractvalue</tt>' instruction extracts the value of a member field
4533 from an <a href="#t_aggregate">aggregate</a> value.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4534
4535<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4536<p>The first operand of an '<tt>extractvalue</tt>' instruction is a value
Chris Lattner61c70e92010-08-28 04:09:24 +0000[diff] [blame]4537 of <a href="#t_struct">struct</a> or
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4538 <a href="#t_array">array</a> type. The operands are constant indices to
4539 specify which value to extract in a similar manner as indices in a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4540 '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
Frits van Bommel13242892010-12-05 20:54:38 +0000[diff] [blame]4541 <p>The major differences to <tt>getelementptr</tt> indexing are:</p>
4542 <ul>
4543 <li>Since the value being indexed is not a pointer, the first index is
4544 omitted and assumed to be zero.</li>
4545 <li>At least one index must be specified.</li>
4546 <li>Not only struct indices but also array indices must be in
4547 bounds.</li>
4548 </ul>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4549
4550<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4551<p>The result is the value at the position in the aggregate specified by the
4552 index operands.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4553
4554<h5>Example:</h5>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4555<pre>
Gabor Greifa5b6f452009-10-28 13:14:50 +0000[diff] [blame]4556 &lt;result&gt; = extractvalue {i32, float} %agg, 0 <i>; yields i32</i>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4557</pre>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4558
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4559</div>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4560
4561<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4562<h4>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4563 <a name="i_insertvalue">'<tt>insertvalue</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4564</h4>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4565
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4566<div>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4567
4568<h5>Syntax:</h5>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4569<pre>
Bill Wendling194229e2011-07-26 20:42:28 +0000[diff] [blame]4570 &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]4571</pre>
4572
4573<h5>Overview:</h5>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4574<p>The '<tt>insertvalue</tt>' instruction inserts a value into a member field
4575 in an <a href="#t_aggregate">aggregate</a> value.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4576
4577<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4578<p>The first operand of an '<tt>insertvalue</tt>' instruction is a value
Chris Lattner61c70e92010-08-28 04:09:24 +0000[diff] [blame]4579 of <a href="#t_struct">struct</a> or
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4580 <a href="#t_array">array</a> type. The second operand is a first-class
4581 value to insert. The following operands are constant indices indicating
4582 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]4583 '<tt><a href="#i_extractvalue">extractvalue</a></tt>' instruction. The
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4584 value to insert must have the same type as the value identified by the
4585 indices.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4586
4587<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4588<p>The result is an aggregate of the same type as <tt>val</tt>. Its value is
4589 that of <tt>val</tt> except that the value at the position specified by the
4590 indices is that of <tt>elt</tt>.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4591
4592<h5>Example:</h5>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4593<pre>
Chris Lattner8645d1a2011-05-22 07:18:08 +0000[diff] [blame]4594 %agg1 = insertvalue {i32, float} undef, i32 1, 0 <i>; yields {i32 1, float undef}</i>
4595 %agg2 = insertvalue {i32, float} %agg1, float %val, 1 <i>; yields {i32 1, float %val}</i>
4596 %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]4597</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4598
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4599</div>
4600
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4601</div>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4602
4603<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4604<h3>
Chris Lattner884a9702006-08-15 00:45:58 +0000[diff] [blame]4605 <a name="memoryops">Memory Access and Addressing Operations</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4606</h3>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4607
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4608<div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4609
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4610<p>A key design point of an SSA-based representation is how it represents
4611 memory. In LLVM, no memory locations are in SSA form, which makes things
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]4612 very simple. This section describes how to read, write, and allocate
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4613 memory in LLVM.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4614
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4615<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4616<h4>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4617 <a name="i_alloca">'<tt>alloca</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4618</h4>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4619
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4620<div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4621
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4622<h5>Syntax:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4623<pre>
Dan Gohmanf75a7d32010-05-28 01:14:11 +0000[diff] [blame]4624 &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]4625</pre>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4626
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4627<h5>Overview:</h5>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]4628<p>The '<tt>alloca</tt>' instruction allocates memory on the stack frame of the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4629 currently executing function, to be automatically released when this function
4630 returns to its caller. The object is always allocated in the generic address
4631 space (address space zero).</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4632
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4633<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4634<p>The '<tt>alloca</tt>' instruction
4635 allocates <tt>sizeof(&lt;type&gt;)*NumElements</tt> bytes of memory on the
4636 runtime stack, returning a pointer of the appropriate type to the program.
4637 If "NumElements" is specified, it is the number of elements allocated,
4638 otherwise "NumElements" is defaulted to be one. If a constant alignment is
4639 specified, the value result of the allocation is guaranteed to be aligned to
4640 at least that boundary. If not specified, or if zero, the target can choose
4641 to align the allocation on any convenient boundary compatible with the
4642 type.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4643
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4644<p>'<tt>type</tt>' may be any sized type.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4645
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4646<h5>Semantics:</h5>
Bill Wendling871eb0a2009-05-08 20:49:29 +0000[diff] [blame]4647<p>Memory is allocated; a pointer is returned. The operation is undefined if
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4648 there is insufficient stack space for the allocation. '<tt>alloca</tt>'d
4649 memory is automatically released when the function returns. The
4650 '<tt>alloca</tt>' instruction is commonly used to represent automatic
4651 variables that must have an address available. When the function returns
4652 (either with the <tt><a href="#i_ret">ret</a></tt>
4653 or <tt><a href="#i_unwind">unwind</a></tt> instructions), the memory is
4654 reclaimed. Allocating zero bytes is legal, but the result is undefined.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4655
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4656<h5>Example:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4657<pre>
Dan Gohman81e21672009-01-04 23:49:44 +0000[diff] [blame]4658 %ptr = alloca i32 <i>; yields {i32*}:ptr</i>
4659 %ptr = alloca i32, i32 4 <i>; yields {i32*}:ptr</i>
4660 %ptr = alloca i32, i32 4, align 1024 <i>; yields {i32*}:ptr</i>
4661 %ptr = alloca i32, align 1024 <i>; yields {i32*}:ptr</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4662</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4663
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4664</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4665
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4666<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4667<h4>
4668 <a name="i_load">'<tt>load</tt>' Instruction</a>
4669</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4670
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4671<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4672
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4673<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4674<pre>
Eli Friedmanf03bb262011-08-12 22:50:01 +0000[diff] [blame]4675 &lt;result&gt; = load [volatile] &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;][, !nontemporal !&lt;index&gt;]
4676 &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]4677 !&lt;index&gt; = !{ i32 1 }
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4678</pre>
4679
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4680<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4681<p>The '<tt>load</tt>' instruction is used to read from memory.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4682
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4683<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4684<p>The argument to the '<tt>load</tt>' instruction specifies the memory address
4685 from which to load. The pointer must point to
4686 a <a href="#t_firstclass">first class</a> type. If the <tt>load</tt> is
4687 marked as <tt>volatile</tt>, then the optimizer is not allowed to modify the
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]4688 number or order of execution of this <tt>load</tt> with other <a
4689 href="#volatile">volatile operations</a>.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4690
Eli Friedman21006d42011-08-09 23:02:53 +0000[diff] [blame]4691<p>If the <code>load</code> is marked as <code>atomic</code>, it takes an extra
4692 <a href="#ordering">ordering</a> and optional <code>singlethread</code>
4693 argument. The <code>release</code> and <code>acq_rel</code> orderings are
4694 not valid on <code>load</code> instructions. Atomic loads produce <a
4695 href="#memorymodel">defined</a> results when they may see multiple atomic
4696 stores. The type of the pointee must be an integer type whose bit width
4697 is a power of two greater than or equal to eight and less than or equal
4698 to a target-specific size limit. <code>align</code> must be explicitly
4699 specified on atomic loads, and the load has undefined behavior if the
4700 alignment is not set to a value which is at least the size in bytes of
4701 the pointee. <code>!nontemporal</code> does not have any defined semantics
4702 for atomic loads.</p>
4703
Bill Wendling7c78dbb2010-02-25 21:23:24 +0000[diff] [blame]4704<p>The optional constant <tt>align</tt> argument specifies the alignment of the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4705 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]4706 omitted <tt>align</tt> argument means that the operation has the preferential
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4707 alignment for the target. It is the responsibility of the code emitter to
4708 ensure that the alignment information is correct. Overestimating the
Bill Wendling7c78dbb2010-02-25 21:23:24 +0000[diff] [blame]4709 alignment results in undefined behavior. Underestimating the alignment may
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4710 produce less efficient code. An alignment of 1 is always safe.</p>
4711
Bill Wendling7c78dbb2010-02-25 21:23:24 +0000[diff] [blame]4712<p>The optional <tt>!nontemporal</tt> metadata must reference a single
4713 metatadata name &lt;index&gt; corresponding to a metadata node with
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]4714 one <tt>i32</tt> entry of value 1. The existence of
Bill Wendling7c78dbb2010-02-25 21:23:24 +0000[diff] [blame]4715 the <tt>!nontemporal</tt> metatadata on the instruction tells the optimizer
4716 and code generator that this load is not expected to be reused in the cache.
4717 The code generator may select special instructions to save cache bandwidth,
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]4718 such as the <tt>MOVNT</tt> instruction on x86.</p>
David Greene8939b0d2010-02-16 20:50:18 +0000[diff] [blame]4719
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4720<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4721<p>The location of memory pointed to is loaded. If the value being loaded is of
4722 scalar type then the number of bytes read does not exceed the minimum number
4723 of bytes needed to hold all bits of the type. For example, loading an
4724 <tt>i24</tt> reads at most three bytes. When loading a value of a type like
4725 <tt>i20</tt> with a size that is not an integral number of bytes, the result
4726 is undefined if the value was not originally written using a store of the
4727 same type.</p>
4728
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4729<h5>Examples:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4730<pre>
4731 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
4732 <a href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4733 %val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4734</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4735
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4736</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4737
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4738<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4739<h4>
4740 <a name="i_store">'<tt>store</tt>' Instruction</a>
4741</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4742
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4743<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4744
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4745<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4746<pre>
Eli Friedmanf03bb262011-08-12 22:50:01 +0000[diff] [blame]4747 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>
4748 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]4749</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4750
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4751<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4752<p>The '<tt>store</tt>' instruction is used to write to memory.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4753
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4754<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4755<p>There are two arguments to the '<tt>store</tt>' instruction: a value to store
4756 and an address at which to store it. The type of the
4757 '<tt>&lt;pointer&gt;</tt>' operand must be a pointer to
4758 the <a href="#t_firstclass">first class</a> type of the
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]4759 '<tt>&lt;value&gt;</tt>' operand. If the <tt>store</tt> is marked as
4760 <tt>volatile</tt>, then the optimizer is not allowed to modify the number or
4761 order of execution of this <tt>store</tt> with other <a
4762 href="#volatile">volatile operations</a>.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4763
Eli Friedman21006d42011-08-09 23:02:53 +0000[diff] [blame]4764<p>If the <code>store</code> is marked as <code>atomic</code>, it takes an extra
4765 <a href="#ordering">ordering</a> and optional <code>singlethread</code>
4766 argument. The <code>acquire</code> and <code>acq_rel</code> orderings aren't
4767 valid on <code>store</code> instructions. Atomic loads produce <a
4768 href="#memorymodel">defined</a> results when they may see multiple atomic
4769 stores. The type of the pointee must be an integer type whose bit width
4770 is a power of two greater than or equal to eight and less than or equal
4771 to a target-specific size limit. <code>align</code> must be explicitly
4772 specified on atomic stores, and the store has undefined behavior if the
4773 alignment is not set to a value which is at least the size in bytes of
4774 the pointee. <code>!nontemporal</code> does not have any defined semantics
4775 for atomic stores.</p>
4776
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4777<p>The optional constant "align" argument specifies the alignment of the
4778 operation (that is, the alignment of the memory address). A value of 0 or an
4779 omitted "align" argument means that the operation has the preferential
4780 alignment for the target. It is the responsibility of the code emitter to
4781 ensure that the alignment information is correct. Overestimating the
4782 alignment results in an undefined behavior. Underestimating the alignment may
4783 produce less efficient code. An alignment of 1 is always safe.</p>
4784
David Greene8939b0d2010-02-16 20:50:18 +0000[diff] [blame]4785<p>The optional !nontemporal metadata must reference a single metatadata
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]4786 name &lt;index&gt; corresponding to a metadata node with one i32 entry of
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]4787 value 1. The existence of the !nontemporal metatadata on the
David Greene8939b0d2010-02-16 20:50:18 +0000[diff] [blame]4788 instruction tells the optimizer and code generator that this load is
4789 not expected to be reused in the cache. The code generator may
4790 select special instructions to save cache bandwidth, such as the
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]4791 MOVNT instruction on x86.</p>
David Greene8939b0d2010-02-16 20:50:18 +0000[diff] [blame]4792
4793
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4794<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4795<p>The contents of memory are updated to contain '<tt>&lt;value&gt;</tt>' at the
4796 location specified by the '<tt>&lt;pointer&gt;</tt>' operand. If
4797 '<tt>&lt;value&gt;</tt>' is of scalar type then the number of bytes written
4798 does not exceed the minimum number of bytes needed to hold all bits of the
4799 type. For example, storing an <tt>i24</tt> writes at most three bytes. When
4800 writing a value of a type like <tt>i20</tt> with a size that is not an
4801 integral number of bytes, it is unspecified what happens to the extra bits
4802 that do not belong to the type, but they will typically be overwritten.</p>
4803
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4804<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4805<pre>
4806 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Bill Wendling8c6c72d2007-10-22 05:10:05 +0000[diff] [blame]4807 store i32 3, i32* %ptr <i>; yields {void}</i>
4808 %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]4809</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4810
Reid Spencer47ce1792006-11-09 21:15:49 +0000[diff] [blame]4811</div>
4812
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4813<!-- _______________________________________________________________________ -->
NAKAMURA Takumib5bb29c2011-08-12 06:17:17 +0000[diff] [blame]4814<h4>
4815<a name="i_fence">'<tt>fence</tt>' Instruction</a>
4816</h4>
Eli Friedman47f35132011-07-25 23:16:38 +0000[diff] [blame]4817
NAKAMURA Takumib5bb29c2011-08-12 06:17:17 +0000[diff] [blame]4818<div>
Eli Friedman47f35132011-07-25 23:16:38 +0000[diff] [blame]4819
4820<h5>Syntax:</h5>
4821<pre>
4822 fence [singlethread] &lt;ordering&gt; <i>; yields {void}</i>
4823</pre>
4824
4825<h5>Overview:</h5>
4826<p>The '<tt>fence</tt>' instruction is used to introduce happens-before edges
4827between operations.</p>
4828
4829<h5>Arguments:</h5> <p>'<code>fence</code>' instructions take an <a
4830href="#ordering">ordering</a> argument which defines what
4831<i>synchronizes-with</i> edges they add. They can only be given
4832<code>acquire</code>, <code>release</code>, <code>acq_rel</code>, and
4833<code>seq_cst</code> orderings.</p>
4834
4835<h5>Semantics:</h5>
4836<p>A fence <var>A</var> which has (at least) <code>release</code> ordering
4837semantics <i>synchronizes with</i> a fence <var>B</var> with (at least)
4838<code>acquire</code> ordering semantics if and only if there exist atomic
4839operations <var>X</var> and <var>Y</var>, both operating on some atomic object
4840<var>M</var>, such that <var>A</var> is sequenced before <var>X</var>,
4841<var>X</var> modifies <var>M</var> (either directly or through some side effect
4842of a sequence headed by <var>X</var>), <var>Y</var> is sequenced before
4843<var>B</var>, and <var>Y</var> observes <var>M</var>. This provides a
4844<i>happens-before</i> dependency between <var>A</var> and <var>B</var>. Rather
4845than an explicit <code>fence</code>, one (but not both) of the atomic operations
4846<var>X</var> or <var>Y</var> might provide a <code>release</code> or
4847<code>acquire</code> (resp.) ordering constraint and still
4848<i>synchronize-with</i> the explicit <code>fence</code> and establish the
4849<i>happens-before</i> edge.</p>
4850
4851<p>A <code>fence</code> which has <code>seq_cst</code> ordering, in addition to
4852having both <code>acquire</code> and <code>release</code> semantics specified
4853above, participates in the global program order of other <code>seq_cst</code>
4854operations and/or fences.</p>
4855
4856<p>The optional "<a href="#singlethread"><code>singlethread</code></a>" argument
4857specifies that the fence only synchronizes with other fences in the same
4858thread. (This is useful for interacting with signal handlers.)</p>
4859
Eli Friedman47f35132011-07-25 23:16:38 +0000[diff] [blame]4860<h5>Example:</h5>
4861<pre>
4862 fence acquire <i>; yields {void}</i>
4863 fence singlethread seq_cst <i>; yields {void}</i>
4864</pre>
4865
4866</div>
4867
4868<!-- _______________________________________________________________________ -->
NAKAMURA Takumib5bb29c2011-08-12 06:17:17 +0000[diff] [blame]4869<h4>
4870<a name="i_cmpxchg">'<tt>cmpxchg</tt>' Instruction</a>
4871</h4>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]4872
NAKAMURA Takumib5bb29c2011-08-12 06:17:17 +0000[diff] [blame]4873<div>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]4874
4875<h5>Syntax:</h5>
4876<pre>
Eli Friedmanf03bb262011-08-12 22:50:01 +0000[diff] [blame]4877 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]4878</pre>
4879
4880<h5>Overview:</h5>
4881<p>The '<tt>cmpxchg</tt>' instruction is used to atomically modify memory.
4882It loads a value in memory and compares it to a given value. If they are
4883equal, it stores a new value into the memory.</p>
4884
4885<h5>Arguments:</h5>
4886<p>There are three arguments to the '<code>cmpxchg</code>' instruction: an
4887address to operate on, a value to compare to the value currently be at that
4888address, and a new value to place at that address if the compared values are
4889equal. The type of '<var>&lt;cmp&gt;</var>' must be an integer type whose
4890bit width is a power of two greater than or equal to eight and less than
4891or equal to a target-specific size limit. '<var>&lt;cmp&gt;</var>' and
4892'<var>&lt;new&gt;</var>' must have the same type, and the type of
4893'<var>&lt;pointer&gt;</var>' must be a pointer to that type. If the
4894<code>cmpxchg</code> is marked as <code>volatile</code>, then the
4895optimizer is not allowed to modify the number or order of execution
4896of this <code>cmpxchg</code> with other <a href="#volatile">volatile
4897operations</a>.</p>
4898
4899<!-- FIXME: Extend allowed types. -->
4900
4901<p>The <a href="#ordering"><var>ordering</var></a> argument specifies how this
4902<code>cmpxchg</code> synchronizes with other atomic operations.</p>
4903
4904<p>The optional "<code>singlethread</code>" argument declares that the
4905<code>cmpxchg</code> is only atomic with respect to code (usually signal
4906handlers) running in the same thread as the <code>cmpxchg</code>. Otherwise the
4907cmpxchg is atomic with respect to all other code in the system.</p>
4908
4909<p>The pointer passed into cmpxchg must have alignment greater than or equal to
4910the size in memory of the operand.
4911
4912<h5>Semantics:</h5>
4913<p>The contents of memory at the location specified by the
4914'<tt>&lt;pointer&gt;</tt>' operand is read and compared to
4915'<tt>&lt;cmp&gt;</tt>'; if the read value is the equal,
4916'<tt>&lt;new&gt;</tt>' is written. The original value at the location
4917is returned.
4918
4919<p>A successful <code>cmpxchg</code> is a read-modify-write instruction for the
4920purpose of identifying <a href="#release_sequence">release sequences</a>. A
4921failed <code>cmpxchg</code> is equivalent to an atomic load with an ordering
4922parameter determined by dropping any <code>release</code> part of the
4923<code>cmpxchg</code>'s ordering.</p>
4924
4925<!--
4926FIXME: Is compare_exchange_weak() necessary? (Consider after we've done
4927optimization work on ARM.)
4928
4929FIXME: Is a weaker ordering constraint on failure helpful in practice?
4930-->
4931
4932<h5>Example:</h5>
4933<pre>
4934entry:
4935 %orig = atomic <a href="#i_load">load</a> i32* %ptr unordered <i>; yields {i32}</i>
4936 <a href="#i_br">br</a> label %loop
4937
4938loop:
4939 %cmp = <a href="#i_phi">phi</a> i32 [ %orig, %entry ], [%old, %loop]
4940 %squared = <a href="#i_mul">mul</a> i32 %cmp, %cmp
4941 %old = cmpxchg i32* %ptr, i32 %cmp, i32 %squared <i>; yields {i32}</i>
4942 %success = <a href="#i_icmp">icmp</a> eq i32 %cmp, %old
4943 <a href="#i_br">br</a> i1 %success, label %done, label %loop
4944
4945done:
4946 ...
4947</pre>
4948
4949</div>
4950
4951<!-- _______________________________________________________________________ -->
NAKAMURA Takumib5bb29c2011-08-12 06:17:17 +0000[diff] [blame]4952<h4>
4953<a name="i_atomicrmw">'<tt>atomicrmw</tt>' Instruction</a>
4954</h4>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]4955
NAKAMURA Takumib5bb29c2011-08-12 06:17:17 +0000[diff] [blame]4956<div>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]4957
4958<h5>Syntax:</h5>
4959<pre>
Eli Friedmanf03bb262011-08-12 22:50:01 +0000[diff] [blame]4960 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]4961</pre>
4962
4963<h5>Overview:</h5>
4964<p>The '<tt>atomicrmw</tt>' instruction is used to atomically modify memory.</p>
4965
4966<h5>Arguments:</h5>
4967<p>There are three arguments to the '<code>atomicrmw</code>' instruction: an
4968operation to apply, an address whose value to modify, an argument to the
4969operation. The operation must be one of the following keywords:</p>
4970<ul>
4971 <li>xchg</li>
4972 <li>add</li>
4973 <li>sub</li>
4974 <li>and</li>
4975 <li>nand</li>
4976 <li>or</li>
4977 <li>xor</li>
4978 <li>max</li>
4979 <li>min</li>
4980 <li>umax</li>
4981 <li>umin</li>
4982</ul>
4983
4984<p>The type of '<var>&lt;value&gt;</var>' must be an integer type whose
4985bit width is a power of two greater than or equal to eight and less than
4986or equal to a target-specific size limit. The type of the
4987'<code>&lt;pointer&gt;</code>' operand must be a pointer to that type.
4988If the <code>atomicrmw</code> is marked as <code>volatile</code>, then the
4989optimizer is not allowed to modify the number or order of execution of this
4990<code>atomicrmw</code> with other <a href="#volatile">volatile
4991 operations</a>.</p>
4992
4993<!-- FIXME: Extend allowed types. -->
4994
4995<h5>Semantics:</h5>
4996<p>The contents of memory at the location specified by the
4997'<tt>&lt;pointer&gt;</tt>' operand are atomically read, modified, and written
4998back. The original value at the location is returned. The modification is
4999specified by the <var>operation</var> argument:</p>
5000
5001<ul>
5002 <li>xchg: <code>*ptr = val</code></li>
5003 <li>add: <code>*ptr = *ptr + val</code></li>
5004 <li>sub: <code>*ptr = *ptr - val</code></li>
5005 <li>and: <code>*ptr = *ptr &amp; val</code></li>
5006 <li>nand: <code>*ptr = ~(*ptr &amp; val)</code></li>
5007 <li>or: <code>*ptr = *ptr | val</code></li>
5008 <li>xor: <code>*ptr = *ptr ^ val</code></li>
5009 <li>max: <code>*ptr = *ptr &gt; val ? *ptr : val</code> (using a signed comparison)</li>
5010 <li>min: <code>*ptr = *ptr &lt; val ? *ptr : val</code> (using a signed comparison)</li>
5011 <li>umax: <code>*ptr = *ptr &gt; val ? *ptr : val</code> (using an unsigned comparison)</li>
5012 <li>umin: <code>*ptr = *ptr &lt; val ? *ptr : val</code> (using an unsigned comparison)</li>
5013</ul>
5014
5015<h5>Example:</h5>
5016<pre>
5017 %old = atomicrmw add i32* %ptr, i32 1 acquire <i>; yields {i32}</i>
5018</pre>
5019
5020</div>
5021
5022<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5023<h4>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5024 <a name="i_getelementptr">'<tt>getelementptr</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5025</h4>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5026
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5027<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5028
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]5029<h5>Syntax:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5030<pre>
Matthijs Kooijmane49d0bc2008-10-13 13:44:15 +0000[diff] [blame]5031 &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]5032 &lt;result&gt; = getelementptr inbounds &lt;pty&gt;* &lt;ptrval&gt;{, &lt;ty&gt; &lt;idx&gt;}*
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5033</pre>
5034
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]5035<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5036<p>The '<tt>getelementptr</tt>' instruction is used to get the address of a
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]5037 subelement of an <a href="#t_aggregate">aggregate</a> data structure.
5038 It performs address calculation only and does not access memory.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5039
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]5040<h5>Arguments:</h5>
Matthijs Kooijmane49d0bc2008-10-13 13:44:15 +0000[diff] [blame]5041<p>The first argument is always a pointer, and forms the basis of the
Chris Lattnerc8eef442009-07-29 06:44:13 +0000[diff] [blame]5042 calculation. The remaining arguments are indices that indicate which of the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5043 elements of the aggregate object are indexed. The interpretation of each
5044 index is dependent on the type being indexed into. The first index always
5045 indexes the pointer value given as the first argument, the second index
5046 indexes a value of the type pointed to (not necessarily the value directly
5047 pointed to, since the first index can be non-zero), etc. The first type
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]5048 indexed into must be a pointer value, subsequent types can be arrays,
Chris Lattner61c70e92010-08-28 04:09:24 +0000[diff] [blame]5049 vectors, and structs. Note that subsequent types being indexed into
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]5050 can never be pointers, since that would require loading the pointer before
5051 continuing calculation.</p>
Matthijs Kooijmane49d0bc2008-10-13 13:44:15 +0000[diff] [blame]5052
5053<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]5054 When indexing into a (optionally packed) structure, only <tt>i32</tt>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]5055 integer <b>constants</b> are allowed. When indexing into an array, pointer
5056 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]5057 constant. These integers are treated as signed values where relevant.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5058
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5059<p>For example, let's consider a C code fragment and how it gets compiled to
5060 LLVM:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5061
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]5062<pre class="doc_code">
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]5063struct RT {
5064 char A;
Chris Lattnercabc8462007-05-29 15:43:56 +0000[diff] [blame]5065 int B[10][20];
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]5066 char C;
5067};
5068struct ST {
Chris Lattnercabc8462007-05-29 15:43:56 +0000[diff] [blame]5069 int X;
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]5070 double Y;
5071 struct RT Z;
5072};
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5073
Chris Lattnercabc8462007-05-29 15:43:56 +0000[diff] [blame]5074int *foo(struct ST *s) {
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]5075 return &amp;s[1].Z.B[5][13];
5076}
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5077</pre>
5078
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5079<p>The LLVM code generated by the GCC frontend is:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5080
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]5081<pre class="doc_code">
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]5082%RT = <a href="#namedtypes">type</a> { i8 , [10 x [20 x i32]], i8 }
5083%ST = <a href="#namedtypes">type</a> { i32, double, %RT }
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5084
Dan Gohman4df605b2009-07-25 02:23:48 +0000[diff] [blame]5085define i32* @foo(%ST* %s) {
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]5086entry:
5087 %reg = getelementptr %ST* %s, i32 1, i32 2, i32 1, i32 5, i32 13
5088 ret i32* %reg
5089}
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5090</pre>
5091
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]5092<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5093<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]5094 type, which is a pointer, yielding a '<tt>%ST</tt>' = '<tt>{ i32, double, %RT
5095 }</tt>' type, a structure. The second index indexes into the third element
5096 of the structure, yielding a '<tt>%RT</tt>' = '<tt>{ i8 , [10 x [20 x i32]],
5097 i8 }</tt>' type, another structure. The third index indexes into the second
5098 element of the structure, yielding a '<tt>[10 x [20 x i32]]</tt>' type, an
5099 array. The two dimensions of the array are subscripted into, yielding an
5100 '<tt>i32</tt>' type. The '<tt>getelementptr</tt>' instruction returns a
5101 pointer to this element, thus computing a value of '<tt>i32*</tt>' type.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5102
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5103<p>Note that it is perfectly legal to index partially through a structure,
5104 returning a pointer to an inner element. Because of this, the LLVM code for
5105 the given testcase is equivalent to:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5106
5107<pre>
Dan Gohman4df605b2009-07-25 02:23:48 +0000[diff] [blame]5108 define i32* @foo(%ST* %s) {
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5109 %t1 = getelementptr %ST* %s, i32 1 <i>; yields %ST*:%t1</i>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]5110 %t2 = getelementptr %ST* %t1, i32 0, i32 2 <i>; yields %RT*:%t2</i>
5111 %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]5112 %t4 = getelementptr [10 x [20 x i32]]* %t3, i32 0, i32 5 <i>; yields [20 x i32]*:%t4</i>
5113 %t5 = getelementptr [20 x i32]* %t4, i32 0, i32 13 <i>; yields i32*:%t5</i>
5114 ret i32* %t5
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5115 }
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]5116</pre>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]5117
Dan Gohmandd8004d2009-07-27 21:53:46 +0000[diff] [blame]5118<p>If the <tt>inbounds</tt> keyword is present, the result value of the
Dan Gohman27ef9972010-04-23 15:23:32 +0000[diff] [blame]5119 <tt>getelementptr</tt> is a <a href="#trapvalues">trap value</a> if the
5120 base pointer is not an <i>in bounds</i> address of an allocated object,
5121 or if any of the addresses that would be formed by successive addition of
5122 the offsets implied by the indices to the base address with infinitely
Eli Friedman266246c2011-08-12 23:37:55 +0000[diff] [blame]5123 precise signed arithmetic are not an <i>in bounds</i> address of that
5124 allocated object. The <i>in bounds</i> addresses for an allocated object
5125 are all the addresses that point into the object, plus the address one
5126 byte past the end.</p>
Dan Gohmandd8004d2009-07-27 21:53:46 +0000[diff] [blame]5127
5128<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]5129 the base address with silently-wrapping two's complement arithmetic. If the
5130 offsets have a different width from the pointer, they are sign-extended or
5131 truncated to the width of the pointer. The result value of the
5132 <tt>getelementptr</tt> may be outside the object pointed to by the base
5133 pointer. The result value may not necessarily be used to access memory
5134 though, even if it happens to point into allocated storage. See the
5135 <a href="#pointeraliasing">Pointer Aliasing Rules</a> section for more
5136 information.</p>
Dan Gohmandd8004d2009-07-27 21:53:46 +0000[diff] [blame]5137
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5138<p>The getelementptr instruction is often confusing. For some more insight into
5139 how it works, see <a href="GetElementPtr.html">the getelementptr FAQ</a>.</p>
Chris Lattner884a9702006-08-15 00:45:58 +0000[diff] [blame]5140
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]5141<h5>Example:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5142<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5143 <i>; yields [12 x i8]*:aptr</i>
Matthijs Kooijmane49d0bc2008-10-13 13:44:15 +0000[diff] [blame]5144 %aptr = getelementptr {i32, [12 x i8]}* %saptr, i64 0, i32 1
5145 <i>; yields i8*:vptr</i>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]5146 %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]5147 <i>; yields i8*:eptr</i>
5148 %eptr = getelementptr [12 x i8]* %aptr, i64 0, i32 1
Sanjiv Gupta9f805c22009-04-25 07:27:44 +0000[diff] [blame]5149 <i>; yields i32*:iptr</i>
Sanjiv Gupta16ffa802009-04-24 16:38:13 +0000[diff] [blame]5150 %iptr = getelementptr [10 x i32]* @arr, i16 0, i16 0
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5151</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5152
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5153</div>
Reid Spencer47ce1792006-11-09 21:15:49 +0000[diff] [blame]5154
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5155</div>
5156
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]5157<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5158<h3>
5159 <a name="convertops">Conversion Operations</a>
5160</h3>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5161
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5162<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5163
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5164<p>The instructions in this category are the conversion instructions (casting)
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5165 which all take a single operand and a type. They perform various bit
5166 conversions on the operand.</p>
5167
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]5168<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5169<h4>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5170 <a name="i_trunc">'<tt>trunc .. to</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5171</h4>
5172
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5173<div>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5174
5175<h5>Syntax:</h5>
5176<pre>
5177 &lt;result&gt; = trunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
5178</pre>
5179
5180<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5181<p>The '<tt>trunc</tt>' instruction truncates its operand to the
5182 type <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5183
5184<h5>Arguments:</h5>
Nadav Rotem8c20ec52011-02-24 21:01:34 +0000[diff] [blame]5185<p>The '<tt>trunc</tt>' instruction takes a value to trunc, and a type to trunc it to.
5186 Both types must be of <a href="#t_integer">integer</a> types, or vectors
5187 of the same number of integers.
5188 The bit size of the <tt>value</tt> must be larger than
5189 the bit size of the destination type, <tt>ty2</tt>.
5190 Equal sized types are not allowed.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5191
5192<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5193<p>The '<tt>trunc</tt>' instruction truncates the high order bits
5194 in <tt>value</tt> and converts the remaining bits to <tt>ty2</tt>. Since the
5195 source size must be larger than the destination size, <tt>trunc</tt> cannot
5196 be a <i>no-op cast</i>. It will always truncate bits.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5197
5198<h5>Example:</h5>
5199<pre>
Nadav Rotem8c20ec52011-02-24 21:01:34 +0000[diff] [blame]5200 %X = trunc i32 257 to i8 <i>; yields i8:1</i>
5201 %Y = trunc i32 123 to i1 <i>; yields i1:true</i>
5202 %Z = trunc i32 122 to i1 <i>; yields i1:false</i>
5203 %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]5204</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5205
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5206</div>
5207
5208<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5209<h4>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5210 <a name="i_zext">'<tt>zext .. to</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5211</h4>
5212
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5213<div>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5214
5215<h5>Syntax:</h5>
5216<pre>
5217 &lt;result&gt; = zext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
5218</pre>
5219
5220<h5>Overview:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5221<p>The '<tt>zext</tt>' instruction zero extends its operand to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5222 <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5223
5224
5225<h5>Arguments:</h5>
Nadav Rotemed9b9342011-02-20 12:37:50 +0000[diff] [blame]5226<p>The '<tt>zext</tt>' instruction takes a value to cast, and a type to cast it to.
5227 Both types must be of <a href="#t_integer">integer</a> types, or vectors
5228 of the same number of integers.
5229 The bit size of the <tt>value</tt> must be smaller than
5230 the bit size of the destination type,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5231 <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5232
5233<h5>Semantics:</h5>
5234<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]5235 bits until it reaches the size of the destination type, <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5236
Reid Spencerb5929522007-01-12 15:46:11 +0000[diff] [blame]5237<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]5238
5239<h5>Example:</h5>
5240<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5241 %X = zext i32 257 to i64 <i>; yields i64:257</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]5242 %Y = zext i1 true to i32 <i>; yields i32:1</i>
Nadav Rotemed9b9342011-02-20 12:37:50 +0000[diff] [blame]5243 %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]5244</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5245
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5246</div>
5247
5248<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5249<h4>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5250 <a name="i_sext">'<tt>sext .. to</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5251</h4>
5252
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5253<div>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5254
5255<h5>Syntax:</h5>
5256<pre>
5257 &lt;result&gt; = sext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
5258</pre>
5259
5260<h5>Overview:</h5>
5261<p>The '<tt>sext</tt>' sign extends <tt>value</tt> to the type <tt>ty2</tt>.</p>
5262
5263<h5>Arguments:</h5>
Nadav Rotem8c20ec52011-02-24 21:01:34 +0000[diff] [blame]5264<p>The '<tt>sext</tt>' instruction takes a value to cast, and a type to cast it to.
5265 Both types must be of <a href="#t_integer">integer</a> types, or vectors
5266 of the same number of integers.
5267 The bit size of the <tt>value</tt> must be smaller than
5268 the bit size of the destination type,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5269 <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5270
5271<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5272<p>The '<tt>sext</tt>' instruction performs a sign extension by copying the sign
5273 bit (highest order bit) of the <tt>value</tt> until it reaches the bit size
5274 of the type <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5275
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]5276<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]5277
5278<h5>Example:</h5>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5279<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5280 %X = sext i8 -1 to i16 <i>; yields i16 :65535</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]5281 %Y = sext i1 true to i32 <i>; yields i32:-1</i>
Nadav Rotem8c20ec52011-02-24 21:01:34 +0000[diff] [blame]5282 %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]5283</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5284
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5285</div>
5286
5287<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5288<h4>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]5289 <a name="i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5290</h4>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]5291
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5292<div>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]5293
5294<h5>Syntax:</h5>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]5295<pre>
5296 &lt;result&gt; = fptrunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
5297</pre>
5298
5299<h5>Overview:</h5>
5300<p>The '<tt>fptrunc</tt>' instruction truncates <tt>value</tt> to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5301 <tt>ty2</tt>.</p>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]5302
5303<h5>Arguments:</h5>
5304<p>The '<tt>fptrunc</tt>' instruction takes a <a href="#t_floating">floating
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5305 point</a> value to cast and a <a href="#t_floating">floating point</a> type
5306 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]5307 <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]5308 <i>no-op cast</i>.</p>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]5309
5310<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5311<p>The '<tt>fptrunc</tt>' instruction truncates a <tt>value</tt> from a larger
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5312 <a href="#t_floating">floating point</a> type to a smaller
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5313 <a href="#t_floating">floating point</a> type. If the value cannot fit
5314 within the destination type, <tt>ty2</tt>, then the results are
5315 undefined.</p>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]5316
5317<h5>Example:</h5>
5318<pre>
5319 %X = fptrunc double 123.0 to float <i>; yields float:123.0</i>
5320 %Y = fptrunc double 1.0E+300 to float <i>; yields undefined</i>
5321</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5322
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]5323</div>
5324
5325<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5326<h4>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5327 <a name="i_fpext">'<tt>fpext .. to</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5328</h4>
5329
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5330<div>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5331
5332<h5>Syntax:</h5>
5333<pre>
5334 &lt;result&gt; = fpext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
5335</pre>
5336
5337<h5>Overview:</h5>
5338<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]5339 floating point value.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5340
5341<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5342<p>The '<tt>fpext</tt>' instruction takes a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5343 <a href="#t_floating">floating point</a> <tt>value</tt> to cast, and
5344 a <a href="#t_floating">floating point</a> type to cast it to. The source
5345 type must be smaller than the destination type.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5346
5347<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]5348<p>The '<tt>fpext</tt>' instruction extends the <tt>value</tt> from a smaller
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5349 <a href="#t_floating">floating point</a> type to a larger
5350 <a href="#t_floating">floating point</a> type. The <tt>fpext</tt> cannot be
5351 used to make a <i>no-op cast</i> because it always changes bits. Use
5352 <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]5353
5354<h5>Example:</h5>
5355<pre>
Nick Lewycky5bb3ece2011-03-31 18:20:19 +0000[diff] [blame]5356 %X = fpext float 3.125 to double <i>; yields double:3.125000e+00</i>
5357 %Y = fpext double %X to fp128 <i>; yields fp128:0xL00000000000000004000900000000000</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5358</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5359
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5360</div>
5361
5362<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5363<h4>
Reid Spencer24d6da52007-01-21 00:29:26 +0000[diff] [blame]5364 <a name="i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5365</h4>
5366
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5367<div>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5368
5369<h5>Syntax:</h5>
5370<pre>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]5371 &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]5372</pre>
5373
5374<h5>Overview:</h5>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]5375<p>The '<tt>fptoui</tt>' converts a floating point <tt>value</tt> to its
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5376 unsigned integer equivalent of type <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5377
5378<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5379<p>The '<tt>fptoui</tt>' instruction takes a value to cast, which must be a
5380 scalar or vector <a href="#t_floating">floating point</a> value, and a type
5381 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
5382 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
5383 vector integer type with the same number of elements as <tt>ty</tt></p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5384
5385<h5>Semantics:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5386<p>The '<tt>fptoui</tt>' instruction converts its
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5387 <a href="#t_floating">floating point</a> operand into the nearest (rounding
5388 towards zero) unsigned integer value. If the value cannot fit
5389 in <tt>ty2</tt>, the results are undefined.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5390
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5391<h5>Example:</h5>
5392<pre>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]5393 %X = fptoui double 123.0 to i32 <i>; yields i32:123</i>
Chris Lattner88519042007-09-22 03:17:52 +0000[diff] [blame]5394 %Y = fptoui float 1.0E+300 to i1 <i>; yields undefined:1</i>
Gabor Greif6a292012009-10-28 09:21:30 +0000[diff] [blame]5395 %Z = fptoui float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5396</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5397
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5398</div>
5399
5400<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5401<h4>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]5402 <a name="i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5403</h4>
5404
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5405<div>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5406
5407<h5>Syntax:</h5>
5408<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]5409 &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]5410</pre>
5411
5412<h5>Overview:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5413<p>The '<tt>fptosi</tt>' instruction converts
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5414 <a href="#t_floating">floating point</a> <tt>value</tt> to
5415 type <tt>ty2</tt>.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5416
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]5417<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5418<p>The '<tt>fptosi</tt>' instruction takes a value to cast, which must be a
5419 scalar or vector <a href="#t_floating">floating point</a> value, and a type
5420 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
5421 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
5422 vector integer type with the same number of elements as <tt>ty</tt></p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5423
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]5424<h5>Semantics:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5425<p>The '<tt>fptosi</tt>' instruction converts its
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5426 <a href="#t_floating">floating point</a> operand into the nearest (rounding
5427 towards zero) signed integer value. If the value cannot fit in <tt>ty2</tt>,
5428 the results are undefined.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5429
Chris Lattner33ba0d92001-07-09 00:26:23 +0000[diff] [blame]5430<h5>Example:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5431<pre>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]5432 %X = fptosi double -123.0 to i32 <i>; yields i32:-123</i>
Chris Lattner88519042007-09-22 03:17:52 +0000[diff] [blame]5433 %Y = fptosi float 1.0E-247 to i1 <i>; yields undefined:1</i>
Gabor Greif6a292012009-10-28 09:21:30 +0000[diff] [blame]5434 %Z = fptosi float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5435</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5436
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5437</div>
5438
5439<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5440<h4>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]5441 <a name="i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5442</h4>
5443
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5444<div>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5445
5446<h5>Syntax:</h5>
5447<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]5448 &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]5449</pre>
5450
5451<h5>Overview:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]5452<p>The '<tt>uitofp</tt>' instruction regards <tt>value</tt> as an unsigned
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5453 integer and converts that value to the <tt>ty2</tt> type.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5454
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5455<h5>Arguments:</h5>
Nate Begemanb348d182007-11-17 03:58:34 +0000[diff] [blame]5456<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]5457 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
5458 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
5459 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
5460 floating point type with the same number of elements as <tt>ty</tt></p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5461
5462<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]5463<p>The '<tt>uitofp</tt>' instruction interprets its operand as an unsigned
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5464 integer quantity and converts it to the corresponding floating point
5465 value. If the value cannot fit in the floating point value, the results are
5466 undefined.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5467
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5468<h5>Example:</h5>
5469<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5470 %X = uitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]5471 %Y = uitofp i8 -1 to double <i>; yields double:255.0</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5472</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5473
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5474</div>
5475
5476<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5477<h4>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]5478 <a name="i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5479</h4>
5480
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5481<div>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5482
5483<h5>Syntax:</h5>
5484<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]5485 &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]5486</pre>
5487
5488<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5489<p>The '<tt>sitofp</tt>' instruction regards <tt>value</tt> as a signed integer
5490 and converts that value to the <tt>ty2</tt> type.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5491
5492<h5>Arguments:</h5>
Nate Begemanb348d182007-11-17 03:58:34 +0000[diff] [blame]5493<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]5494 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
5495 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
5496 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
5497 floating point type with the same number of elements as <tt>ty</tt></p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5498
5499<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5500<p>The '<tt>sitofp</tt>' instruction interprets its operand as a signed integer
5501 quantity and converts it to the corresponding floating point value. If the
5502 value cannot fit in the floating point value, the results are undefined.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5503
5504<h5>Example:</h5>
5505<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5506 %X = sitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]5507 %Y = sitofp i8 -1 to double <i>; yields double:-1.0</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5508</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5509
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5510</div>
5511
5512<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5513<h4>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]5514 <a name="i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5515</h4>
5516
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5517<div>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]5518
5519<h5>Syntax:</h5>
5520<pre>
5521 &lt;result&gt; = ptrtoint &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
5522</pre>
5523
5524<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5525<p>The '<tt>ptrtoint</tt>' instruction converts the pointer <tt>value</tt> to
5526 the integer type <tt>ty2</tt>.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]5527
5528<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5529<p>The '<tt>ptrtoint</tt>' instruction takes a <tt>value</tt> to cast, which
5530 must be a <a href="#t_pointer">pointer</a> value, and a type to cast it to
5531 <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a> type.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]5532
5533<h5>Semantics:</h5>
5534<p>The '<tt>ptrtoint</tt>' instruction converts <tt>value</tt> to integer type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5535 <tt>ty2</tt> by interpreting the pointer value as an integer and either
5536 truncating or zero extending that value to the size of the integer type. If
5537 <tt>value</tt> is smaller than <tt>ty2</tt> then a zero extension is done. If
5538 <tt>value</tt> is larger than <tt>ty2</tt> then a truncation is done. If they
5539 are the same size, then nothing is done (<i>no-op cast</i>) other than a type
5540 change.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]5541
5542<h5>Example:</h5>
5543<pre>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5544 %X = ptrtoint i32* %X to i8 <i>; yields truncation on 32-bit architecture</i>
5545 %Y = ptrtoint i32* %x to i64 <i>; yields zero extension on 32-bit architecture</i>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]5546</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5547
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]5548</div>
5549
5550<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5551<h4>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]5552 <a name="i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5553</h4>
5554
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5555<div>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]5556
5557<h5>Syntax:</h5>
5558<pre>
5559 &lt;result&gt; = inttoptr &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
5560</pre>
5561
5562<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5563<p>The '<tt>inttoptr</tt>' instruction converts an integer <tt>value</tt> to a
5564 pointer type, <tt>ty2</tt>.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]5565
5566<h5>Arguments:</h5>
Duncan Sands8036ca42007-03-30 12:22:09 +0000[diff] [blame]5567<p>The '<tt>inttoptr</tt>' instruction takes an <a href="#t_integer">integer</a>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5568 value to cast, and a type to cast it to, which must be a
5569 <a href="#t_pointer">pointer</a> type.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]5570
5571<h5>Semantics:</h5>
5572<p>The '<tt>inttoptr</tt>' instruction converts <tt>value</tt> to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5573 <tt>ty2</tt> by applying either a zero extension or a truncation depending on
5574 the size of the integer <tt>value</tt>. If <tt>value</tt> is larger than the
5575 size of a pointer then a truncation is done. If <tt>value</tt> is smaller
5576 than the size of a pointer then a zero extension is done. If they are the
5577 same size, nothing is done (<i>no-op cast</i>).</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]5578
5579<h5>Example:</h5>
5580<pre>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5581 %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]5582 %Y = inttoptr i32 255 to i32* <i>; yields no-op on 32-bit architecture</i>
5583 %Z = inttoptr i64 0 to i32* <i>; yields truncation on 32-bit architecture</i>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]5584</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5585
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]5586</div>
5587
5588<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5589<h4>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]5590 <a name="i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5591</h4>
5592
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5593<div>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5594
5595<h5>Syntax:</h5>
5596<pre>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]5597 &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]5598</pre>
5599
5600<h5>Overview:</h5>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]5601<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5602 <tt>ty2</tt> without changing any bits.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5603
5604<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5605<p>The '<tt>bitcast</tt>' instruction takes a value to cast, which must be a
5606 non-aggregate first class value, and a type to cast it to, which must also be
5607 a non-aggregate <a href="#t_firstclass">first class</a> type. The bit sizes
5608 of <tt>value</tt> and the destination type, <tt>ty2</tt>, must be
5609 identical. If the source type is a pointer, the destination type must also be
5610 a pointer. This instruction supports bitwise conversion of vectors to
5611 integers and to vectors of other types (as long as they have the same
5612 size).</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5613
5614<h5>Semantics:</h5>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]5615<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5616 <tt>ty2</tt>. It is always a <i>no-op cast</i> because no bits change with
5617 this conversion. The conversion is done as if the <tt>value</tt> had been
5618 stored to memory and read back as type <tt>ty2</tt>. Pointer types may only
5619 be converted to other pointer types with this instruction. To convert
5620 pointers to other types, use the <a href="#i_inttoptr">inttoptr</a> or
5621 <a href="#i_ptrtoint">ptrtoint</a> instructions first.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5622
5623<h5>Example:</h5>
5624<pre>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5625 %X = bitcast i8 255 to i8 <i>; yields i8 :-1</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5626 %Y = bitcast i32* %x to sint* <i>; yields sint*:%x</i>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5627 %Z = bitcast &lt;2 x int&gt; %V to i64; <i>; yields i64: %V</i>
Chris Lattner33ba0d92001-07-09 00:26:23 +0000[diff] [blame]5628</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5629
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5630</div>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5631
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5632</div>
5633
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5634<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5635<h3>
5636 <a name="otherops">Other Operations</a>
5637</h3>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5638
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5639<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5640
5641<p>The instructions in this category are the "miscellaneous" instructions, which
5642 defy better classification.</p>
5643
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5644<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5645<h4>
5646 <a name="i_icmp">'<tt>icmp</tt>' Instruction</a>
5647</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5648
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5649<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5650
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5651<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5652<pre>
5653 &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]5654</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5655
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5656<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5657<p>The '<tt>icmp</tt>' instruction returns a boolean value or a vector of
5658 boolean values based on comparison of its two integer, integer vector, or
5659 pointer operands.</p>
5660
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5661<h5>Arguments:</h5>
5662<p>The '<tt>icmp</tt>' instruction takes three operands. The first operand is
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5663 the condition code indicating the kind of comparison to perform. It is not a
5664 value, just a keyword. The possible condition code are:</p>
5665
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5666<ol>
5667 <li><tt>eq</tt>: equal</li>
5668 <li><tt>ne</tt>: not equal </li>
5669 <li><tt>ugt</tt>: unsigned greater than</li>
5670 <li><tt>uge</tt>: unsigned greater or equal</li>
5671 <li><tt>ult</tt>: unsigned less than</li>
5672 <li><tt>ule</tt>: unsigned less or equal</li>
5673 <li><tt>sgt</tt>: signed greater than</li>
5674 <li><tt>sge</tt>: signed greater or equal</li>
5675 <li><tt>slt</tt>: signed less than</li>
5676 <li><tt>sle</tt>: signed less or equal</li>
5677</ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5678
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]5679<p>The remaining two arguments must be <a href="#t_integer">integer</a> or
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5680 <a href="#t_pointer">pointer</a> or integer <a href="#t_vector">vector</a>
5681 typed. They must also be identical types.</p>
5682
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5683<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5684<p>The '<tt>icmp</tt>' compares <tt>op1</tt> and <tt>op2</tt> according to the
5685 condition code given as <tt>cond</tt>. The comparison performed always yields
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]5686 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]5687 result, as follows:</p>
5688
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5689<ol>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5690 <li><tt>eq</tt>: yields <tt>true</tt> if the operands are equal,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5691 <tt>false</tt> otherwise. No sign interpretation is necessary or
5692 performed.</li>
5693
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5694 <li><tt>ne</tt>: yields <tt>true</tt> if the operands are unequal,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5695 <tt>false</tt> otherwise. No sign interpretation is necessary or
5696 performed.</li>
5697
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5698 <li><tt>ugt</tt>: interprets the operands as unsigned values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5699 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
5700
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5701 <li><tt>uge</tt>: interprets the operands as unsigned values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5702 <tt>true</tt> if <tt>op1</tt> is greater than or equal
5703 to <tt>op2</tt>.</li>
5704
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5705 <li><tt>ult</tt>: interprets the operands as unsigned values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5706 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
5707
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5708 <li><tt>ule</tt>: interprets the operands as unsigned values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5709 <tt>true</tt> if <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
5710
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5711 <li><tt>sgt</tt>: interprets the operands as signed values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5712 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
5713
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5714 <li><tt>sge</tt>: interprets the operands as signed values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5715 <tt>true</tt> if <tt>op1</tt> is greater than or equal
5716 to <tt>op2</tt>.</li>
5717
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5718 <li><tt>slt</tt>: interprets the operands as signed values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5719 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
5720
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5721 <li><tt>sle</tt>: interprets the operands as signed values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5722 <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]5723</ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5724
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5725<p>If the operands are <a href="#t_pointer">pointer</a> typed, the pointer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5726 values are compared as if they were integers.</p>
5727
5728<p>If the operands are integer vectors, then they are compared element by
5729 element. The result is an <tt>i1</tt> vector with the same number of elements
5730 as the values being compared. Otherwise, the result is an <tt>i1</tt>.</p>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5731
5732<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5733<pre>
5734 &lt;result&gt; = icmp eq i32 4, 5 <i>; yields: result=false</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5735 &lt;result&gt; = icmp ne float* %X, %X <i>; yields: result=false</i>
5736 &lt;result&gt; = icmp ult i16 4, 5 <i>; yields: result=true</i>
5737 &lt;result&gt; = icmp sgt i16 4, 5 <i>; yields: result=false</i>
5738 &lt;result&gt; = icmp ule i16 -4, 5 <i>; yields: result=false</i>
5739 &lt;result&gt; = icmp sge i16 4, 5 <i>; yields: result=false</i>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5740</pre>
Dan Gohmanc766f722009-01-22 01:39:38 +0000[diff] [blame]5741
5742<p>Note that the code generator does not yet support vector types with
5743 the <tt>icmp</tt> instruction.</p>
5744
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5745</div>
5746
5747<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5748<h4>
5749 <a name="i_fcmp">'<tt>fcmp</tt>' Instruction</a>
5750</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5751
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5752<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5753
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5754<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5755<pre>
5756 &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]5757</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5758
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5759<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5760<p>The '<tt>fcmp</tt>' instruction returns a boolean value or vector of boolean
5761 values based on comparison of its operands.</p>
5762
5763<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]5764(<a href="#t_integer"><tt>i1</tt></a>).</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5765
5766<p>If the operands are floating point vectors, then the result type is a vector
5767 of boolean with the same number of elements as the operands being
5768 compared.</p>
5769
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5770<h5>Arguments:</h5>
5771<p>The '<tt>fcmp</tt>' instruction takes three operands. The first operand is
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5772 the condition code indicating the kind of comparison to perform. It is not a
5773 value, just a keyword. The possible condition code are:</p>
5774
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5775<ol>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]5776 <li><tt>false</tt>: no comparison, always returns false</li>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5777 <li><tt>oeq</tt>: ordered and equal</li>
5778 <li><tt>ogt</tt>: ordered and greater than </li>
5779 <li><tt>oge</tt>: ordered and greater than or equal</li>
5780 <li><tt>olt</tt>: ordered and less than </li>
5781 <li><tt>ole</tt>: ordered and less than or equal</li>
5782 <li><tt>one</tt>: ordered and not equal</li>
5783 <li><tt>ord</tt>: ordered (no nans)</li>
5784 <li><tt>ueq</tt>: unordered or equal</li>
5785 <li><tt>ugt</tt>: unordered or greater than </li>
5786 <li><tt>uge</tt>: unordered or greater than or equal</li>
5787 <li><tt>ult</tt>: unordered or less than </li>
5788 <li><tt>ule</tt>: unordered or less than or equal</li>
5789 <li><tt>une</tt>: unordered or not equal</li>
5790 <li><tt>uno</tt>: unordered (either nans)</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]5791 <li><tt>true</tt>: no comparison, always returns true</li>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5792</ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5793
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5794<p><i>Ordered</i> means that neither operand is a QNAN while
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5795 <i>unordered</i> means that either operand may be a QNAN.</p>
5796
5797<p>Each of <tt>val1</tt> and <tt>val2</tt> arguments must be either
5798 a <a href="#t_floating">floating point</a> type or
5799 a <a href="#t_vector">vector</a> of floating point type. They must have
5800 identical types.</p>
5801
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5802<h5>Semantics:</h5>
Gabor Greiffb224a22008-08-07 21:46:00 +0000[diff] [blame]5803<p>The '<tt>fcmp</tt>' instruction compares <tt>op1</tt> and <tt>op2</tt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5804 according to the condition code given as <tt>cond</tt>. If the operands are
5805 vectors, then the vectors are compared element by element. Each comparison
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]5806 performed always yields an <a href="#t_integer">i1</a> result, as
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5807 follows:</p>
5808
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5809<ol>
5810 <li><tt>false</tt>: always yields <tt>false</tt>, regardless of operands.</li>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5811
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5812 <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]5813 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
5814
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]5815 <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]5816 <tt>op1</tt> is greater than <tt>op2</tt>.</li>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5817
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5818 <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]5819 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
5820
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5821 <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]5822 <tt>op1</tt> is less than <tt>op2</tt>.</li>
5823
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5824 <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]5825 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
5826
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5827 <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]5828 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
5829
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]5830 <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]5831
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5832 <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]5833 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
5834
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5835 <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]5836 <tt>op1</tt> is greater than <tt>op2</tt>.</li>
5837
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5838 <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]5839 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
5840
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5841 <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]5842 <tt>op1</tt> is less than <tt>op2</tt>.</li>
5843
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5844 <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]5845 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
5846
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5847 <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]5848 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
5849
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]5850 <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]5851
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5852 <li><tt>true</tt>: always yields <tt>true</tt>, regardless of operands.</li>
5853</ol>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5854
5855<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5856<pre>
5857 &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]5858 &lt;result&gt; = fcmp one float 4.0, 5.0 <i>; yields: result=true</i>
5859 &lt;result&gt; = fcmp olt float 4.0, 5.0 <i>; yields: result=true</i>
5860 &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]5861</pre>
Dan Gohmanc766f722009-01-22 01:39:38 +0000[diff] [blame]5862
5863<p>Note that the code generator does not yet support vector types with
5864 the <tt>fcmp</tt> instruction.</p>
5865
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5866</div>
5867
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5868<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5869<h4>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5870 <a name="i_phi">'<tt>phi</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5871</h4>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5872
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5873<div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5874
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5875<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5876<pre>
5877 &lt;result&gt; = phi &lt;ty&gt; [ &lt;val0&gt;, &lt;label0&gt;], ...
5878</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5879
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5880<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5881<p>The '<tt>phi</tt>' instruction is used to implement the &#966; node in the
5882 SSA graph representing the function.</p>
5883
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5884<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5885<p>The type of the incoming values is specified with the first type field. After
5886 this, the '<tt>phi</tt>' instruction takes a list of pairs as arguments, with
5887 one pair for each predecessor basic block of the current block. Only values
5888 of <a href="#t_firstclass">first class</a> type may be used as the value
5889 arguments to the PHI node. Only labels may be used as the label
5890 arguments.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5891
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5892<p>There must be no non-phi instructions between the start of a basic block and
5893 the PHI instructions: i.e. PHI instructions must be first in a basic
5894 block.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5895
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5896<p>For the purposes of the SSA form, the use of each incoming value is deemed to
5897 occur on the edge from the corresponding predecessor block to the current
5898 block (but after any definition of an '<tt>invoke</tt>' instruction's return
5899 value on the same edge).</p>
Jay Foadd2449092009-06-03 10:20:10 +0000[diff] [blame]5900
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5901<h5>Semantics:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5902<p>At runtime, the '<tt>phi</tt>' instruction logically takes on the value
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5903 specified by the pair corresponding to the predecessor basic block that
5904 executed just prior to the current block.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5905
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5906<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5907<pre>
5908Loop: ; Infinite loop that counts from 0 on up...
5909 %indvar = phi i32 [ 0, %LoopHeader ], [ %nextindvar, %Loop ]
5910 %nextindvar = add i32 %indvar, 1
5911 br label %Loop
5912</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5913
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5914</div>
5915
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5916<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5917<h4>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5918 <a name="i_select">'<tt>select</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5919</h4>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5920
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5921<div>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5922
5923<h5>Syntax:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5924<pre>
Dan Gohmanf72fb672008-09-09 01:02:47 +0000[diff] [blame]5925 &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>
5926
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]5927 <i>selty</i> is either i1 or {&lt;N x i1&gt;}
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5928</pre>
5929
5930<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5931<p>The '<tt>select</tt>' instruction is used to choose one value based on a
5932 condition, without branching.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5933
5934
5935<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5936<p>The '<tt>select</tt>' instruction requires an 'i1' value or a vector of 'i1'
5937 values indicating the condition, and two values of the
5938 same <a href="#t_firstclass">first class</a> type. If the val1/val2 are
5939 vectors and the condition is a scalar, then entire vectors are selected, not
5940 individual elements.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5941
5942<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5943<p>If the condition is an i1 and it evaluates to 1, the instruction returns the
5944 first value argument; otherwise, it returns the second value argument.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5945
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5946<p>If the condition is a vector of i1, then the value arguments must be vectors
5947 of the same size, and the selection is done element by element.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5948
5949<h5>Example:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5950<pre>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]5951 %X = select i1 true, i8 17, i8 42 <i>; yields i8:17</i>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5952</pre>
Dan Gohmanc766f722009-01-22 01:39:38 +0000[diff] [blame]5953
5954<p>Note that the code generator does not yet support conditions
5955 with vector type.</p>
5956
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5957</div>
5958
Robert Bocchino05ccd702006-01-15 20:48:27 +0000[diff] [blame]5959<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5960<h4>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5961 <a name="i_call">'<tt>call</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5962</h4>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5963
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5964<div>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5965
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]5966<h5>Syntax:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5967<pre>
Devang Patel307e8ab2008-10-07 17:48:33 +0000[diff] [blame]5968 &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]5969</pre>
5970
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]5971<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5972<p>The '<tt>call</tt>' instruction represents a simple function call.</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5973
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]5974<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5975<p>This instruction requires several arguments:</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5976
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]5977<ol>
Jeffrey Yasskin95fa80a2010-01-09 19:44:16 +0000[diff] [blame]5978 <li>The optional "tail" marker indicates that the callee function does not
5979 access any allocas or varargs in the caller. Note that calls may be
5980 marked "tail" even if they do not occur before
5981 a <a href="#i_ret"><tt>ret</tt></a> instruction. If the "tail" marker is
5982 present, the function call is eligible for tail call optimization,
5983 but <a href="CodeGenerator.html#tailcallopt">might not in fact be
Evan Chengdc444e92010-03-08 21:05:02 +0000[diff] [blame]5984 optimized into a jump</a>. The code generator may optimize calls marked
5985 "tail" with either 1) automatic <a href="CodeGenerator.html#sibcallopt">
5986 sibling call optimization</a> when the caller and callee have
5987 matching signatures, or 2) forced tail call optimization when the
5988 following extra requirements are met:
Jeffrey Yasskin95fa80a2010-01-09 19:44:16 +0000[diff] [blame]5989 <ul>
5990 <li>Caller and callee both have the calling
5991 convention <tt>fastcc</tt>.</li>
5992 <li>The call is in tail position (ret immediately follows call and ret
5993 uses value of call or is void).</li>
5994 <li>Option <tt>-tailcallopt</tt> is enabled,
Dan Gohmanfbbee8d2010-03-02 01:08:11 +0000[diff] [blame]5995 or <code>llvm::GuaranteedTailCallOpt</code> is <code>true</code>.</li>
Jeffrey Yasskin95fa80a2010-01-09 19:44:16 +0000[diff] [blame]5996 <li><a href="CodeGenerator.html#tailcallopt">Platform specific
5997 constraints are met.</a></li>
5998 </ul>
5999 </li>
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]6000
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6001 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
6002 convention</a> the call should use. If none is specified, the call
Jeffrey Yasskin95fa80a2010-01-09 19:44:16 +0000[diff] [blame]6003 defaults to using C calling conventions. The calling convention of the
6004 call must match the calling convention of the target function, or else the
6005 behavior is undefined.</li>
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]6006
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6007 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
6008 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
6009 '<tt>inreg</tt>' attributes are valid here.</li>
6010
6011 <li>'<tt>ty</tt>': the type of the call instruction itself which is also the
6012 type of the return value. Functions that return no value are marked
6013 <tt><a href="#t_void">void</a></tt>.</li>
6014
6015 <li>'<tt>fnty</tt>': shall be the signature of the pointer to function value
6016 being invoked. The argument types must match the types implied by this
6017 signature. This type can be omitted if the function is not varargs and if
6018 the function type does not return a pointer to a function.</li>
6019
6020 <li>'<tt>fnptrval</tt>': An LLVM value containing a pointer to a function to
6021 be invoked. In most cases, this is a direct function invocation, but
6022 indirect <tt>call</tt>s are just as possible, calling an arbitrary pointer
6023 to function value.</li>
6024
6025 <li>'<tt>function args</tt>': argument list whose types match the function
Chris Lattner0724fbd2010-03-02 06:36:51 +0000[diff] [blame]6026 signature argument types and parameter attributes. All arguments must be
6027 of <a href="#t_firstclass">first class</a> type. If the function
6028 signature indicates the function accepts a variable number of arguments,
6029 the extra arguments can be specified.</li>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6030
6031 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
6032 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
6033 '<tt>readnone</tt>' attributes are valid here.</li>
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]6034</ol>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]6035
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]6036<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6037<p>The '<tt>call</tt>' instruction is used to cause control flow to transfer to
6038 a specified function, with its incoming arguments bound to the specified
6039 values. Upon a '<tt><a href="#i_ret">ret</a></tt>' instruction in the called
6040 function, control flow continues with the instruction after the function
6041 call, and the return value of the function is bound to the result
6042 argument.</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]6043
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]6044<h5>Example:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]6045<pre>
Nick Lewyckydb7e3c92007-09-08 13:57:50 +0000[diff] [blame]6046 %retval = call i32 @test(i32 %argc)
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]6047 call i32 (i8*, ...)* @printf(i8* %msg, i32 12, i8 42) <i>; yields i32</i>
Chris Lattner772fccf2008-03-21 17:24:17 +0000[diff] [blame]6048 %X = tail call i32 @foo() <i>; yields i32</i>
6049 %Y = tail call <a href="#callingconv">fastcc</a> i32 @foo() <i>; yields i32</i>
6050 call void %foo(i8 97 signext)
Devang Patelc3fc6df2008-03-10 20:49:15 +0000[diff] [blame]6051
6052 %struct.A = type { i32, i8 }
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]6053 %r = call %struct.A @foo() <i>; yields { 32, i8 }</i>
Dan Gohmanb1e6b962008-10-04 19:00:07 +0000[diff] [blame]6054 %gr = extractvalue %struct.A %r, 0 <i>; yields i32</i>
6055 %gr1 = extractvalue %struct.A %r, 1 <i>; yields i8</i>
Chris Lattner85a350f2008-10-08 06:26:11 +0000[diff] [blame]6056 %Z = call void @foo() noreturn <i>; indicates that %foo never returns normally</i>
Matthijs Kooijmancb73d192008-10-07 10:03:45 +0000[diff] [blame]6057 %ZZ = call zeroext i32 @bar() <i>; Return value is %zero extended</i>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]6058</pre>
6059
Dale Johannesen07de8d12009-09-24 18:38:21 +0000[diff] [blame]6060<p>llvm treats calls to some functions with names and arguments that match the
Dale Johannesen9f8380b2009-09-25 17:04:42 +0000[diff] [blame]6061standard C99 library as being the C99 library functions, and may perform
6062optimizations or generate code for them under that assumption. This is
6063something we'd like to change in the future to provide better support for
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]6064freestanding environments and non-C-based languages.</p>
Dale Johannesen07de8d12009-09-24 18:38:21 +0000[diff] [blame]6065
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]6066</div>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]6067
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6068<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6069<h4>
Chris Lattnerfb6977d2006-01-13 23:26:01 +0000[diff] [blame]6070 <a name="i_va_arg">'<tt>va_arg</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6071</h4>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]6072
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6073<div>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]6074
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]6075<h5>Syntax:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]6076<pre>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]6077 &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]6078</pre>
6079
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]6080<h5>Overview:</h5>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]6081<p>The '<tt>va_arg</tt>' instruction is used to access arguments passed through
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6082 the "variable argument" area of a function call. It is used to implement the
6083 <tt>va_arg</tt> macro in C.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]6084
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]6085<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6086<p>This instruction takes a <tt>va_list*</tt> value and the type of the
6087 argument. It returns a value of the specified argument type and increments
6088 the <tt>va_list</tt> to point to the next argument. The actual type
6089 of <tt>va_list</tt> is target specific.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]6090
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]6091<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6092<p>The '<tt>va_arg</tt>' instruction loads an argument of the specified type
6093 from the specified <tt>va_list</tt> and causes the <tt>va_list</tt> to point
6094 to the next argument. For more information, see the variable argument
6095 handling <a href="#int_varargs">Intrinsic Functions</a>.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]6096
6097<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]6098 take a variable number of arguments, for example, the <tt>vfprintf</tt>
6099 function.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]6100
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6101<p><tt>va_arg</tt> is an LLVM instruction instead of
6102 an <a href="#intrinsics">intrinsic function</a> because it takes a type as an
6103 argument.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]6104
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]6105<h5>Example:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]6106<p>See the <a href="#int_varargs">variable argument processing</a> section.</p>
6107
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6108<p>Note that the code generator does not yet fully support va_arg on many
6109 targets. Also, it does not currently support va_arg with aggregate types on
6110 any target.</p>
Dan Gohmanf3e60bd2009-01-12 23:12:39 +0000[diff] [blame]6111
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]6112</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6113
Bill Wendlingf78faf82011-08-02 21:52:38 +0000[diff] [blame]6114<!-- _______________________________________________________________________ -->
6115<h4>
6116 <a name="i_landingpad">'<tt>landingpad</tt>' Instruction</a>
6117</h4>
6118
6119<div>
6120
6121<h5>Syntax:</h5>
6122<pre>
Bill Wendlingbf13ee12011-08-08 08:06:05 +0000[diff] [blame]6123 &lt;resultval&gt; = landingpad &lt;somety&gt; personality &lt;type&gt; &lt;pers_fn&gt; &lt;clause&gt;+
6124 &lt;resultval&gt; = landingpad &lt;somety&gt; personality &lt;type&gt; &lt;pers_fn&gt; cleanup &lt;clause&gt;*
6125
Bill Wendlingf78faf82011-08-02 21:52:38 +0000[diff] [blame]6126 &lt;clause&gt; := catch &lt;type&gt; &lt;value&gt;
Bill Wendlinge6e88262011-08-12 20:24:12 +0000[diff] [blame]6127 &lt;clause&gt; := filter &lt;array constant type&gt; &lt;array constant&gt;
Bill Wendlingf78faf82011-08-02 21:52:38 +0000[diff] [blame]6128</pre>
6129
6130<h5>Overview:</h5>
6131<p>The '<tt>landingpad</tt>' instruction is used by
6132 <a href="ExceptionHandling.html#overview">LLVM's exception handling
6133 system</a> to specify that a basic block is a landing pad &mdash; one where
6134 the exception lands, and corresponds to the code found in the
6135 <i><tt>catch</tt></i> portion of a <i><tt>try/catch</tt></i> sequence. It
6136 defines values supplied by the personality function (<tt>pers_fn</tt>) upon
6137 re-entry to the function. The <tt>resultval</tt> has the
6138 type <tt>somety</tt>.</p>
6139
6140<h5>Arguments:</h5>
6141<p>This instruction takes a <tt>pers_fn</tt> value. This is the personality
6142 function associated with the unwinding mechanism. The optional
6143 <tt>cleanup</tt> flag indicates that the landing pad block is a cleanup.</p>
6144
6145<p>A <tt>clause</tt> begins with the clause type &mdash; <tt>catch</tt>
Bill Wendlinge6e88262011-08-12 20:24:12 +0000[diff] [blame]6146 or <tt>filter</tt> &mdash; and contains the global variable representing the
6147 "type" that may be caught or filtered respectively. Unlike the
6148 <tt>catch</tt> clause, the <tt>filter</tt> clause takes an array constant as
6149 its argument. Use "<tt>[0 x i8**] undef</tt>" for a filter which cannot
6150 throw. The '<tt>landingpad</tt>' instruction must contain <em>at least</em>
Bill Wendlingf78faf82011-08-02 21:52:38 +0000[diff] [blame]6151 one <tt>clause</tt> or the <tt>cleanup</tt> flag.</p>
6152
6153<h5>Semantics:</h5>
6154<p>The '<tt>landingpad</tt>' instruction defines the values which are set by the
6155 personality function (<tt>pers_fn</tt>) upon re-entry to the function, and
6156 therefore the "result type" of the <tt>landingpad</tt> instruction. As with
6157 calling conventions, how the personality function results are represented in
6158 LLVM IR is target specific.</p>
6159
Bill Wendlingb7a01352011-08-03 17:17:06 +0000[diff] [blame]6160<p>The clauses are applied in order from top to bottom. If two
6161 <tt>landingpad</tt> instructions are merged together through inlining, the
Bill Wendling2905c322011-08-08 07:58:58 +0000[diff] [blame]6162 clauses from the calling function are appended to the list of clauses.</p>
Bill Wendlingb7a01352011-08-03 17:17:06 +0000[diff] [blame]6163
Bill Wendlingf78faf82011-08-02 21:52:38 +0000[diff] [blame]6164<p>The <tt>landingpad</tt> instruction has several restrictions:</p>
6165
6166<ul>
6167 <li>A landing pad block is a basic block which is the unwind destination of an
6168 '<tt>invoke</tt>' instruction.</li>
6169 <li>A landing pad block must have a '<tt>landingpad</tt>' instruction as its
6170 first non-PHI instruction.</li>
6171 <li>There can be only one '<tt>landingpad</tt>' instruction within the landing
6172 pad block.</li>
6173 <li>A basic block that is not a landing pad block may not include a
6174 '<tt>landingpad</tt>' instruction.</li>
6175 <li>All '<tt>landingpad</tt>' instructions in a function must have the same
6176 personality function.</li>
6177</ul>
6178
6179<h5>Example:</h5>
6180<pre>
6181 ;; A landing pad which can catch an integer.
6182 %res = landingpad { i8*, i32 } personality i32 (...)* @__gxx_personality_v0
6183 catch i8** @_ZTIi
6184 ;; A landing pad that is a cleanup.
6185 %res = landingpad { i8*, i32 } personality i32 (...)* @__gxx_personality_v0
Bill Wendlinge6e88262011-08-12 20:24:12 +0000[diff] [blame]6186 cleanup
Bill Wendlingf78faf82011-08-02 21:52:38 +0000[diff] [blame]6187 ;; A landing pad which can catch an integer and can only throw a double.
6188 %res = landingpad { i8*, i32 } personality i32 (...)* @__gxx_personality_v0
6189 catch i8** @_ZTIi
Bill Wendlinge6e88262011-08-12 20:24:12 +0000[diff] [blame]6190 filter [1 x i8**] [@_ZTId]
Bill Wendlingf78faf82011-08-02 21:52:38 +0000[diff] [blame]6191</pre>
6192
6193</div>
6194
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6195</div>
6196
6197</div>
6198
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6199<!-- *********************************************************************** -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6200<h2><a name="intrinsics">Intrinsic Functions</a></h2>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]6201<!-- *********************************************************************** -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6202
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6203<div>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6204
6205<p>LLVM supports the notion of an "intrinsic function". These functions have
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6206 well known names and semantics and are required to follow certain
6207 restrictions. Overall, these intrinsics represent an extension mechanism for
6208 the LLVM language that does not require changing all of the transformations
6209 in LLVM when adding to the language (or the bitcode reader/writer, the
6210 parser, etc...).</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6211
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]6212<p>Intrinsic function names must all start with an "<tt>llvm.</tt>" prefix. This
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6213 prefix is reserved in LLVM for intrinsic names; thus, function names may not
6214 begin with this prefix. Intrinsic functions must always be external
6215 functions: you cannot define the body of intrinsic functions. Intrinsic
6216 functions may only be used in call or invoke instructions: it is illegal to
6217 take the address of an intrinsic function. Additionally, because intrinsic
6218 functions are part of the LLVM language, it is required if any are added that
6219 they be documented here.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6220
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6221<p>Some intrinsic functions can be overloaded, i.e., the intrinsic represents a
6222 family of functions that perform the same operation but on different data
6223 types. Because LLVM can represent over 8 million different integer types,
6224 overloading is used commonly to allow an intrinsic function to operate on any
6225 integer type. One or more of the argument types or the result type can be
6226 overloaded to accept any integer type. Argument types may also be defined as
6227 exactly matching a previous argument's type or the result type. This allows
6228 an intrinsic function which accepts multiple arguments, but needs all of them
6229 to be of the same type, to only be overloaded with respect to a single
6230 argument or the result.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6231
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6232<p>Overloaded intrinsics will have the names of its overloaded argument types
6233 encoded into its function name, each preceded by a period. Only those types
6234 which are overloaded result in a name suffix. Arguments whose type is matched
6235 against another type do not. For example, the <tt>llvm.ctpop</tt> function
6236 can take an integer of any width and returns an integer of exactly the same
6237 integer width. This leads to a family of functions such as
6238 <tt>i8 @llvm.ctpop.i8(i8 %val)</tt> and <tt>i29 @llvm.ctpop.i29(i29
6239 %val)</tt>. Only one type, the return type, is overloaded, and only one type
6240 suffix is required. Because the argument's type is matched against the return
6241 type, it does not require its own name suffix.</p>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]6242
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]6243<p>To learn how to add an intrinsic function, please see the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6244 <a href="ExtendingLLVM.html">Extending LLVM Guide</a>.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6245
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6246<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6247<h3>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6248 <a name="int_varargs">Variable Argument Handling Intrinsics</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6249</h3>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6250
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6251<div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6252
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6253<p>Variable argument support is defined in LLVM with
6254 the <a href="#i_va_arg"><tt>va_arg</tt></a> instruction and these three
6255 intrinsic functions. These functions are related to the similarly named
6256 macros defined in the <tt>&lt;stdarg.h&gt;</tt> header file.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6257
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6258<p>All of these functions operate on arguments that use a target-specific value
6259 type "<tt>va_list</tt>". The LLVM assembly language reference manual does
6260 not define what this type is, so all transformations should be prepared to
6261 handle these functions regardless of the type used.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6262
Chris Lattner374ab302006-05-15 17:26:46 +0000[diff] [blame]6263<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]6264 instruction and the variable argument handling intrinsic functions are
6265 used.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6266
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]6267<pre class="doc_code">
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]6268define i32 @test(i32 %X, ...) {
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6269 ; Initialize variable argument processing
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]6270 %ap = alloca i8*
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]6271 %ap2 = bitcast i8** %ap to i8*
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]6272 call void @llvm.va_start(i8* %ap2)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6273
6274 ; Read a single integer argument
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]6275 %tmp = va_arg i8** %ap, i32
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6276
6277 ; Demonstrate usage of llvm.va_copy and llvm.va_end
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]6278 %aq = alloca i8*
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]6279 %aq2 = bitcast i8** %aq to i8*
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]6280 call void @llvm.va_copy(i8* %aq2, i8* %ap2)
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]6281 call void @llvm.va_end(i8* %aq2)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6282
6283 ; Stop processing of arguments.
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]6284 call void @llvm.va_end(i8* %ap2)
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]6285 ret i32 %tmp
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6286}
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]6287
6288declare void @llvm.va_start(i8*)
6289declare void @llvm.va_copy(i8*, i8*)
6290declare void @llvm.va_end(i8*)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6291</pre>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6292
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6293<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6294<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6295 <a name="int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6296</h4>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6297
6298
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6299<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6300
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6301<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6302<pre>
6303 declare void %llvm.va_start(i8* &lt;arglist&gt;)
6304</pre>
6305
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6306<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6307<p>The '<tt>llvm.va_start</tt>' intrinsic initializes <tt>*&lt;arglist&gt;</tt>
6308 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]6309
6310<h5>Arguments:</h5>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]6311<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]6312
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6313<h5>Semantics:</h5>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]6314<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]6315 macro available in C. In a target-dependent way, it initializes
6316 the <tt>va_list</tt> element to which the argument points, so that the next
6317 call to <tt>va_arg</tt> will produce the first variable argument passed to
6318 the function. Unlike the C <tt>va_start</tt> macro, this intrinsic does not
6319 need to know the last argument of the function as the compiler can figure
6320 that out.</p>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]6321
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]6322</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6323
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6324<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6325<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6326 <a name="int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6327</h4>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6328
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6329<div>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]6330
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6331<h5>Syntax:</h5>
6332<pre>
6333 declare void @llvm.va_end(i8* &lt;arglist&gt;)
6334</pre>
6335
6336<h5>Overview:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]6337<p>The '<tt>llvm.va_end</tt>' intrinsic destroys <tt>*&lt;arglist&gt;</tt>,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6338 which has been initialized previously
6339 with <tt><a href="#int_va_start">llvm.va_start</a></tt>
6340 or <tt><a href="#i_va_copy">llvm.va_copy</a></tt>.</p>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]6341
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6342<h5>Arguments:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]6343<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]6344
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6345<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]6346<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]6347 macro available in C. In a target-dependent way, it destroys
6348 the <tt>va_list</tt> element to which the argument points. Calls
6349 to <a href="#int_va_start"><tt>llvm.va_start</tt></a>
6350 and <a href="#int_va_copy"> <tt>llvm.va_copy</tt></a> must be matched exactly
6351 with calls to <tt>llvm.va_end</tt>.</p>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]6352
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]6353</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6354
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6355<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6356<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6357 <a name="int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6358</h4>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6359
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6360<div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6361
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6362<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6363<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]6364 declare void @llvm.va_copy(i8* &lt;destarglist&gt;, i8* &lt;srcarglist&gt;)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6365</pre>
6366
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6367<h5>Overview:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]6368<p>The '<tt>llvm.va_copy</tt>' intrinsic copies the current argument position
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6369 from the source argument list to the destination argument list.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6370
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6371<h5>Arguments:</h5>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]6372<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]6373 The second argument is a pointer to a <tt>va_list</tt> element to copy
6374 from.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6375
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6376<h5>Semantics:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]6377<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]6378 macro available in C. In a target-dependent way, it copies the
6379 source <tt>va_list</tt> element into the destination <tt>va_list</tt>
6380 element. This intrinsic is necessary because
6381 the <tt><a href="#int_va_start"> llvm.va_start</a></tt> intrinsic may be
6382 arbitrarily complex and require, for example, memory allocation.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6383
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]6384</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6385
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6386</div>
6387
Bill Wendling0246bb72011-07-31 06:45:03 +0000[diff] [blame]6388</div>
6389
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6390<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6391<h3>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6392 <a name="int_gc">Accurate Garbage Collection Intrinsics</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6393</h3>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6394
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6395<div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6396
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6397<p>LLVM support for <a href="GarbageCollection.html">Accurate Garbage
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]6398Collection</a> (GC) requires the implementation and generation of these
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6399intrinsics. These intrinsics allow identification of <a href="#int_gcroot">GC
6400roots on the stack</a>, as well as garbage collector implementations that
6401require <a href="#int_gcread">read</a> and <a href="#int_gcwrite">write</a>
6402barriers. Front-ends for type-safe garbage collected languages should generate
6403these intrinsics to make use of the LLVM garbage collectors. For more details,
6404see <a href="GarbageCollection.html">Accurate Garbage Collection with
6405LLVM</a>.</p>
Christopher Lamb303dae92007-12-17 01:00:21 +0000[diff] [blame]6406
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6407<p>The garbage collection intrinsics only operate on objects in the generic
6408 address space (address space zero).</p>
Christopher Lamb303dae92007-12-17 01:00:21 +0000[diff] [blame]6409
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6410<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6411<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6412 <a name="int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6413</h4>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6414
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6415<div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6416
6417<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6418<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]6419 declare void @llvm.gcroot(i8** %ptrloc, i8* %metadata)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6420</pre>
6421
6422<h5>Overview:</h5>
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]6423<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]6424 the code generator, and allows some metadata to be associated with it.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6425
6426<h5>Arguments:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6427<p>The first argument specifies the address of a stack object that contains the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6428 root pointer. The second pointer (which must be either a constant or a
6429 global value address) contains the meta-data to be associated with the
6430 root.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6431
6432<h5>Semantics:</h5>
Chris Lattner05d67092008-04-24 05:59:56 +0000[diff] [blame]6433<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]6434 location. At compile-time, the code generator generates information to allow
6435 the runtime to find the pointer at GC safe points. The '<tt>llvm.gcroot</tt>'
6436 intrinsic may only be used in a function which <a href="#gc">specifies a GC
6437 algorithm</a>.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6438
6439</div>
6440
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6441<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6442<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6443 <a name="int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6444</h4>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6445
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6446<div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6447
6448<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6449<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]6450 declare i8* @llvm.gcread(i8* %ObjPtr, i8** %Ptr)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6451</pre>
6452
6453<h5>Overview:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6454<p>The '<tt>llvm.gcread</tt>' intrinsic identifies reads of references from heap
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6455 locations, allowing garbage collector implementations that require read
6456 barriers.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6457
6458<h5>Arguments:</h5>
Chris Lattner80626e92006-03-14 20:02:51 +0000[diff] [blame]6459<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]6460 allocated from the garbage collector. The first object is a pointer to the
6461 start of the referenced object, if needed by the language runtime (otherwise
6462 null).</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6463
6464<h5>Semantics:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6465<p>The '<tt>llvm.gcread</tt>' intrinsic has the same semantics as a load
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6466 instruction, but may be replaced with substantially more complex code by the
6467 garbage collector runtime, as needed. The '<tt>llvm.gcread</tt>' intrinsic
6468 may only be used in a function which <a href="#gc">specifies a GC
6469 algorithm</a>.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6470
6471</div>
6472
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6473<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6474<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6475 <a name="int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6476</h4>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6477
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6478<div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6479
6480<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6481<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]6482 declare void @llvm.gcwrite(i8* %P1, i8* %Obj, i8** %P2)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6483</pre>
6484
6485<h5>Overview:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6486<p>The '<tt>llvm.gcwrite</tt>' intrinsic identifies writes of references to heap
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6487 locations, allowing garbage collector implementations that require write
6488 barriers (such as generational or reference counting collectors).</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6489
6490<h5>Arguments:</h5>
Chris Lattner80626e92006-03-14 20:02:51 +0000[diff] [blame]6491<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]6492 object to store it to, and the third is the address of the field of Obj to
6493 store to. If the runtime does not require a pointer to the object, Obj may
6494 be null.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6495
6496<h5>Semantics:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6497<p>The '<tt>llvm.gcwrite</tt>' intrinsic has the same semantics as a store
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6498 instruction, but may be replaced with substantially more complex code by the
6499 garbage collector runtime, as needed. The '<tt>llvm.gcwrite</tt>' intrinsic
6500 may only be used in a function which <a href="#gc">specifies a GC
6501 algorithm</a>.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6502
6503</div>
6504
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6505</div>
6506
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6507<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6508<h3>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6509 <a name="int_codegen">Code Generator Intrinsics</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6510</h3>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6511
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6512<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6513
6514<p>These intrinsics are provided by LLVM to expose special features that may
6515 only be implemented with code generator support.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6516
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6517<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6518<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6519 <a name="int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6520</h4>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6521
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6522<div>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6523
6524<h5>Syntax:</h5>
6525<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]6526 declare i8 *@llvm.returnaddress(i32 &lt;level&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6527</pre>
6528
6529<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6530<p>The '<tt>llvm.returnaddress</tt>' intrinsic attempts to compute a
6531 target-specific value indicating the return address of the current function
6532 or one of its callers.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6533
6534<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6535<p>The argument to this intrinsic indicates which function to return the address
6536 for. Zero indicates the calling function, one indicates its caller, etc.
6537 The argument is <b>required</b> to be a constant integer value.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6538
6539<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6540<p>The '<tt>llvm.returnaddress</tt>' intrinsic either returns a pointer
6541 indicating the return address of the specified call frame, or zero if it
6542 cannot be identified. The value returned by this intrinsic is likely to be
6543 incorrect or 0 for arguments other than zero, so it should only be used for
6544 debugging purposes.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6545
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6546<p>Note that calling this intrinsic does not prevent function inlining or other
6547 aggressive transformations, so the value returned may not be that of the
6548 obvious source-language caller.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6549
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6550</div>
6551
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6552<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6553<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6554 <a name="int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6555</h4>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6556
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6557<div>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6558
6559<h5>Syntax:</h5>
6560<pre>
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]6561 declare i8* @llvm.frameaddress(i32 &lt;level&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6562</pre>
6563
6564<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6565<p>The '<tt>llvm.frameaddress</tt>' intrinsic attempts to return the
6566 target-specific frame pointer value for the specified stack frame.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6567
6568<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6569<p>The argument to this intrinsic indicates which function to return the frame
6570 pointer for. Zero indicates the calling function, one indicates its caller,
6571 etc. The argument is <b>required</b> to be a constant integer value.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6572
6573<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6574<p>The '<tt>llvm.frameaddress</tt>' intrinsic either returns a pointer
6575 indicating the frame address of the specified call frame, or zero if it
6576 cannot be identified. The value returned by this intrinsic is likely to be
6577 incorrect or 0 for arguments other than zero, so it should only be used for
6578 debugging purposes.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6579
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6580<p>Note that calling this intrinsic does not prevent function inlining or other
6581 aggressive transformations, so the value returned may not be that of the
6582 obvious source-language caller.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6583
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6584</div>
6585
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]6586<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6587<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6588 <a name="int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6589</h4>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]6590
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6591<div>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]6592
6593<h5>Syntax:</h5>
6594<pre>
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]6595 declare i8* @llvm.stacksave()
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]6596</pre>
6597
6598<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6599<p>The '<tt>llvm.stacksave</tt>' intrinsic is used to remember the current state
6600 of the function stack, for use
6601 with <a href="#int_stackrestore"> <tt>llvm.stackrestore</tt></a>. This is
6602 useful for implementing language features like scoped automatic variable
6603 sized arrays in C99.</p>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]6604
6605<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6606<p>This intrinsic returns a opaque pointer value that can be passed
6607 to <a href="#int_stackrestore"><tt>llvm.stackrestore</tt></a>. When
6608 an <tt>llvm.stackrestore</tt> intrinsic is executed with a value saved
6609 from <tt>llvm.stacksave</tt>, it effectively restores the state of the stack
6610 to the state it was in when the <tt>llvm.stacksave</tt> intrinsic executed.
6611 In practice, this pops any <a href="#i_alloca">alloca</a> blocks from the
6612 stack that were allocated after the <tt>llvm.stacksave</tt> was executed.</p>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]6613
6614</div>
6615
6616<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6617<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6618 <a name="int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6619</h4>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]6620
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6621<div>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]6622
6623<h5>Syntax:</h5>
6624<pre>
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]6625 declare void @llvm.stackrestore(i8* %ptr)
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]6626</pre>
6627
6628<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6629<p>The '<tt>llvm.stackrestore</tt>' intrinsic is used to restore the state of
6630 the function stack to the state it was in when the
6631 corresponding <a href="#int_stacksave"><tt>llvm.stacksave</tt></a> intrinsic
6632 executed. This is useful for implementing language features like scoped
6633 automatic variable sized arrays in C99.</p>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]6634
6635<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6636<p>See the description
6637 for <a href="#int_stacksave"><tt>llvm.stacksave</tt></a>.</p>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]6638
6639</div>
6640
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]6641<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6642<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6643 <a name="int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6644</h4>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]6645
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6646<div>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]6647
6648<h5>Syntax:</h5>
6649<pre>
Bruno Cardoso Lopes9a767332011-06-14 04:58:37 +0000[diff] [blame]6650 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]6651</pre>
6652
6653<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6654<p>The '<tt>llvm.prefetch</tt>' intrinsic is a hint to the code generator to
6655 insert a prefetch instruction if supported; otherwise, it is a noop.
6656 Prefetches have no effect on the behavior of the program but can change its
6657 performance characteristics.</p>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]6658
6659<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6660<p><tt>address</tt> is the address to be prefetched, <tt>rw</tt> is the
6661 specifier determining if the fetch should be for a read (0) or write (1),
6662 and <tt>locality</tt> is a temporal locality specifier ranging from (0) - no
Bruno Cardoso Lopes9a767332011-06-14 04:58:37 +0000[diff] [blame]6663 locality, to (3) - extremely local keep in cache. The <tt>cache type</tt>
6664 specifies whether the prefetch is performed on the data (1) or instruction (0)
6665 cache. The <tt>rw</tt>, <tt>locality</tt> and <tt>cache type</tt> arguments
6666 must be constant integers.</p>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]6667
6668<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6669<p>This intrinsic does not modify the behavior of the program. In particular,
6670 prefetches cannot trap and do not produce a value. On targets that support
6671 this intrinsic, the prefetch can provide hints to the processor cache for
6672 better performance.</p>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]6673
6674</div>
6675
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]6676<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6677<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6678 <a name="int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6679</h4>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]6680
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6681<div>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]6682
6683<h5>Syntax:</h5>
6684<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]6685 declare void @llvm.pcmarker(i32 &lt;id&gt;)
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]6686</pre>
6687
6688<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6689<p>The '<tt>llvm.pcmarker</tt>' intrinsic is a method to export a Program
6690 Counter (PC) in a region of code to simulators and other tools. The method
6691 is target specific, but it is expected that the marker will use exported
6692 symbols to transmit the PC of the marker. The marker makes no guarantees
6693 that it will remain with any specific instruction after optimizations. It is
6694 possible that the presence of a marker will inhibit optimizations. The
6695 intended use is to be inserted after optimizations to allow correlations of
6696 simulation runs.</p>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]6697
6698<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6699<p><tt>id</tt> is a numerical id identifying the marker.</p>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]6700
6701<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6702<p>This intrinsic does not modify the behavior of the program. Backends that do
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]6703 not support this intrinsic may ignore it.</p>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]6704
6705</div>
6706
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]6707<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6708<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6709 <a name="int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6710</h4>
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]6711
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6712<div>
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]6713
6714<h5>Syntax:</h5>
6715<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]6716 declare i64 @llvm.readcyclecounter()
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]6717</pre>
6718
6719<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6720<p>The '<tt>llvm.readcyclecounter</tt>' intrinsic provides access to the cycle
6721 counter register (or similar low latency, high accuracy clocks) on those
6722 targets that support it. On X86, it should map to RDTSC. On Alpha, it
6723 should map to RPCC. As the backing counters overflow quickly (on the order
6724 of 9 seconds on alpha), this should only be used for small timings.</p>
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]6725
6726<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6727<p>When directly supported, reading the cycle counter should not modify any
6728 memory. Implementations are allowed to either return a application specific
6729 value or a system wide value. On backends without support, this is lowered
6730 to a constant 0.</p>
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]6731
6732</div>
6733
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6734</div>
6735
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6736<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6737<h3>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6738 <a name="int_libc">Standard C Library Intrinsics</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6739</h3>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6740
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6741<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6742
6743<p>LLVM provides intrinsics for a few important standard C library functions.
6744 These intrinsics allow source-language front-ends to pass information about
6745 the alignment of the pointer arguments to the code generator, providing
6746 opportunity for more efficient code generation.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6747
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6748<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6749<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6750 <a name="int_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6751</h4>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6752
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6753<div>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6754
6755<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6756<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]6757 integer bit width and for different address spaces. Not all targets support
6758 all bit widths however.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6759
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6760<pre>
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]6761 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]6762 i32 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]6763 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]6764 i64 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6765</pre>
6766
6767<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6768<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
6769 source location to the destination location.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6770
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6771<p>Note that, unlike the standard libc function, the <tt>llvm.memcpy.*</tt>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6772 intrinsics do not return a value, takes extra alignment/isvolatile arguments
6773 and the pointers can be in specified address spaces.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6774
6775<h5>Arguments:</h5>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6776
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6777<p>The first argument is a pointer to the destination, the second is a pointer
6778 to the source. The third argument is an integer argument specifying the
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6779 number of bytes to copy, the fourth argument is the alignment of the
6780 source and destination locations, and the fifth is a boolean indicating a
6781 volatile access.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6782
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]6783<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]6784 then the caller guarantees that both the source and destination pointers are
6785 aligned to that boundary.</p>
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]6786
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]6787<p>If the <tt>isvolatile</tt> parameter is <tt>true</tt>, the
6788 <tt>llvm.memcpy</tt> call is a <a href="#volatile">volatile operation</a>.
6789 The detailed access behavior is not very cleanly specified and it is unwise
6790 to depend on it.</p>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6791
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6792<h5>Semantics:</h5>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6793
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6794<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
6795 source location to the destination location, which are not allowed to
6796 overlap. It copies "len" bytes of memory over. If the argument is known to
6797 be aligned to some boundary, this can be specified as the fourth argument,
6798 otherwise it should be set to 0 or 1.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6799
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6800</div>
6801
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6802<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6803<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6804 <a name="int_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6805</h4>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6806
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6807<div>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6808
6809<h5>Syntax:</h5>
Chris Lattner824b9582008-11-21 16:42:48 +0000[diff] [blame]6810<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]6811 width and for different address space. Not all targets support all bit
6812 widths however.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6813
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6814<pre>
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]6815 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]6816 i32 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]6817 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]6818 i64 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6819</pre>
6820
6821<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6822<p>The '<tt>llvm.memmove.*</tt>' intrinsics move a block of memory from the
6823 source location to the destination location. It is similar to the
6824 '<tt>llvm.memcpy</tt>' intrinsic but allows the two memory locations to
6825 overlap.</p>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6826
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6827<p>Note that, unlike the standard libc function, the <tt>llvm.memmove.*</tt>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6828 intrinsics do not return a value, takes extra alignment/isvolatile arguments
6829 and the pointers can be in specified address spaces.</p>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6830
6831<h5>Arguments:</h5>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6832
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6833<p>The first argument is a pointer to the destination, the second is a pointer
6834 to the source. The third argument is an integer argument specifying the
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6835 number of bytes to copy, the fourth argument is the alignment of the
6836 source and destination locations, and the fifth is a boolean indicating a
6837 volatile access.</p>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6838
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]6839<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]6840 then the caller guarantees that the source and destination pointers are
6841 aligned to that boundary.</p>
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]6842
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]6843<p>If the <tt>isvolatile</tt> parameter is <tt>true</tt>, the
6844 <tt>llvm.memmove</tt> call is a <a href="#volatile">volatile operation</a>.
6845 The detailed access behavior is not very cleanly specified and it is unwise
6846 to depend on it.</p>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6847
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6848<h5>Semantics:</h5>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6849
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6850<p>The '<tt>llvm.memmove.*</tt>' intrinsics copy a block of memory from the
6851 source location to the destination location, which may overlap. It copies
6852 "len" bytes of memory over. If the argument is known to be aligned to some
6853 boundary, this can be specified as the fourth argument, otherwise it should
6854 be set to 0 or 1.</p>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6855
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6856</div>
6857
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6858<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6859<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6860 <a name="int_memset">'<tt>llvm.memset.*</tt>' Intrinsics</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6861</h4>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6862
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6863<div>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6864
6865<h5>Syntax:</h5>
Chris Lattner824b9582008-11-21 16:42:48 +0000[diff] [blame]6866<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]6867 width and for different address spaces. However, not all targets support all
6868 bit widths.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6869
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6870<pre>
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]6871 declare void @llvm.memset.p0i8.i32(i8* &lt;dest&gt;, i8 &lt;val&gt;,
Chris Lattnerff35c3f2010-04-08 00:54:34 +0000[diff] [blame]6872 i32 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]6873 declare void @llvm.memset.p0i8.i64(i8* &lt;dest&gt;, i8 &lt;val&gt;,
Chris Lattnerff35c3f2010-04-08 00:54:34 +0000[diff] [blame]6874 i64 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6875</pre>
6876
6877<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6878<p>The '<tt>llvm.memset.*</tt>' intrinsics fill a block of memory with a
6879 particular byte value.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6880
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6881<p>Note that, unlike the standard libc function, the <tt>llvm.memset</tt>
John Criswellcdcbbfc2010-07-30 16:30:28 +0000[diff] [blame]6882 intrinsic does not return a value and takes extra alignment/volatile
6883 arguments. Also, the destination can be in an arbitrary address space.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6884
6885<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6886<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]6887 byte value with which to fill it, the third argument is an integer argument
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6888 specifying the number of bytes to fill, and the fourth argument is the known
John Criswellcdcbbfc2010-07-30 16:30:28 +0000[diff] [blame]6889 alignment of the destination location.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6890
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]6891<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]6892 then the caller guarantees that the destination pointer is aligned to that
6893 boundary.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6894
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]6895<p>If the <tt>isvolatile</tt> parameter is <tt>true</tt>, the
6896 <tt>llvm.memset</tt> call is a <a href="#volatile">volatile operation</a>.
6897 The detailed access behavior is not very cleanly specified and it is unwise
6898 to depend on it.</p>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6899
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6900<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6901<p>The '<tt>llvm.memset.*</tt>' intrinsics fill "len" bytes of memory starting
6902 at the destination location. If the argument is known to be aligned to some
6903 boundary, this can be specified as the fourth argument, otherwise it should
6904 be set to 0 or 1.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6905
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6906</div>
6907
Chris Lattner32006282004-06-11 02:28:03 +0000[diff] [blame]6908<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6909<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6910 <a name="int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6911</h4>
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]6912
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6913<div>
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]6914
6915<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6916<p>This is an overloaded intrinsic. You can use <tt>llvm.sqrt</tt> on any
6917 floating point or vector of floating point type. Not all targets support all
6918 types however.</p>
6919
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]6920<pre>
Dale Johannesen408f9c12007-10-02 17:47:38 +0000[diff] [blame]6921 declare float @llvm.sqrt.f32(float %Val)
6922 declare double @llvm.sqrt.f64(double %Val)
6923 declare x86_fp80 @llvm.sqrt.f80(x86_fp80 %Val)
6924 declare fp128 @llvm.sqrt.f128(fp128 %Val)
6925 declare ppc_fp128 @llvm.sqrt.ppcf128(ppc_fp128 %Val)
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]6926</pre>
6927
6928<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6929<p>The '<tt>llvm.sqrt</tt>' intrinsics return the sqrt of the specified operand,
6930 returning the same value as the libm '<tt>sqrt</tt>' functions would.
6931 Unlike <tt>sqrt</tt> in libm, however, <tt>llvm.sqrt</tt> has undefined
6932 behavior for negative numbers other than -0.0 (which allows for better
6933 optimization, because there is no need to worry about errno being
6934 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]6935
6936<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6937<p>The argument and return value are floating point numbers of the same
6938 type.</p>
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]6939
6940<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6941<p>This function returns the sqrt of the specified operand if it is a
6942 nonnegative floating point number.</p>
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]6943
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]6944</div>
6945
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6946<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6947<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6948 <a name="int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6949</h4>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6950
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6951<div>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6952
6953<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6954<p>This is an overloaded intrinsic. You can use <tt>llvm.powi</tt> on any
6955 floating point or vector of floating point type. Not all targets support all
6956 types however.</p>
6957
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6958<pre>
Dale Johannesen408f9c12007-10-02 17:47:38 +0000[diff] [blame]6959 declare float @llvm.powi.f32(float %Val, i32 %power)
6960 declare double @llvm.powi.f64(double %Val, i32 %power)
6961 declare x86_fp80 @llvm.powi.f80(x86_fp80 %Val, i32 %power)
6962 declare fp128 @llvm.powi.f128(fp128 %Val, i32 %power)
6963 declare ppc_fp128 @llvm.powi.ppcf128(ppc_fp128 %Val, i32 %power)
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6964</pre>
6965
6966<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6967<p>The '<tt>llvm.powi.*</tt>' intrinsics return the first operand raised to the
6968 specified (positive or negative) power. The order of evaluation of
6969 multiplications is not defined. When a vector of floating point type is
6970 used, the second argument remains a scalar integer value.</p>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6971
6972<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6973<p>The second argument is an integer power, and the first is a value to raise to
6974 that power.</p>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6975
6976<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6977<p>This function returns the first value raised to the second power with an
6978 unspecified sequence of rounding operations.</p>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6979
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6980</div>
6981
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6982<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6983<h4>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6984 <a name="int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6985</h4>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6986
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6987<div>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6988
6989<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6990<p>This is an overloaded intrinsic. You can use <tt>llvm.sin</tt> on any
6991 floating point or vector of floating point type. Not all targets support all
6992 types however.</p>
6993
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6994<pre>
6995 declare float @llvm.sin.f32(float %Val)
6996 declare double @llvm.sin.f64(double %Val)
6997 declare x86_fp80 @llvm.sin.f80(x86_fp80 %Val)
6998 declare fp128 @llvm.sin.f128(fp128 %Val)
6999 declare ppc_fp128 @llvm.sin.ppcf128(ppc_fp128 %Val)
7000</pre>
7001
7002<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7003<p>The '<tt>llvm.sin.*</tt>' intrinsics return the sine of the operand.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7004
7005<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7006<p>The argument and return value are floating point numbers of the same
7007 type.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7008
7009<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7010<p>This function returns the sine of the specified operand, returning the same
7011 values as the libm <tt>sin</tt> functions would, and handles error conditions
7012 in the same way.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7013
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7014</div>
7015
7016<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7017<h4>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7018 <a name="int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7019</h4>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7020
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7021<div>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7022
7023<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7024<p>This is an overloaded intrinsic. You can use <tt>llvm.cos</tt> on any
7025 floating point or vector of floating point type. Not all targets support all
7026 types however.</p>
7027
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7028<pre>
7029 declare float @llvm.cos.f32(float %Val)
7030 declare double @llvm.cos.f64(double %Val)
7031 declare x86_fp80 @llvm.cos.f80(x86_fp80 %Val)
7032 declare fp128 @llvm.cos.f128(fp128 %Val)
7033 declare ppc_fp128 @llvm.cos.ppcf128(ppc_fp128 %Val)
7034</pre>
7035
7036<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7037<p>The '<tt>llvm.cos.*</tt>' intrinsics return the cosine of the operand.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7038
7039<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7040<p>The argument and return value are floating point numbers of the same
7041 type.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7042
7043<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7044<p>This function returns the cosine of the specified operand, returning the same
7045 values as the libm <tt>cos</tt> functions would, and handles error conditions
7046 in the same way.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7047
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7048</div>
7049
7050<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7051<h4>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7052 <a name="int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7053</h4>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7054
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7055<div>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7056
7057<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7058<p>This is an overloaded intrinsic. You can use <tt>llvm.pow</tt> on any
7059 floating point or vector of floating point type. Not all targets support all
7060 types however.</p>
7061
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7062<pre>
7063 declare float @llvm.pow.f32(float %Val, float %Power)
7064 declare double @llvm.pow.f64(double %Val, double %Power)
7065 declare x86_fp80 @llvm.pow.f80(x86_fp80 %Val, x86_fp80 %Power)
7066 declare fp128 @llvm.pow.f128(fp128 %Val, fp128 %Power)
7067 declare ppc_fp128 @llvm.pow.ppcf128(ppc_fp128 %Val, ppc_fp128 Power)
7068</pre>
7069
7070<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7071<p>The '<tt>llvm.pow.*</tt>' intrinsics return the first operand raised to the
7072 specified (positive or negative) power.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7073
7074<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7075<p>The second argument is a floating point power, and the first is a value to
7076 raise to that power.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7077
7078<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7079<p>This function returns the first value raised to the second power, returning
7080 the same values as the libm <tt>pow</tt> functions would, and handles error
7081 conditions in the same way.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7082
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7083</div>
7084
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7085</div>
7086
Dan Gohman4e9011c2011-05-23 21:13:03 +0000[diff] [blame]7087<!-- _______________________________________________________________________ -->
7088<h4>
7089 <a name="int_exp">'<tt>llvm.exp.*</tt>' Intrinsic</a>
7090</h4>
7091
7092<div>
7093
7094<h5>Syntax:</h5>
7095<p>This is an overloaded intrinsic. You can use <tt>llvm.exp</tt> on any
7096 floating point or vector of floating point type. Not all targets support all
7097 types however.</p>
7098
7099<pre>
7100 declare float @llvm.exp.f32(float %Val)
7101 declare double @llvm.exp.f64(double %Val)
7102 declare x86_fp80 @llvm.exp.f80(x86_fp80 %Val)
7103 declare fp128 @llvm.exp.f128(fp128 %Val)
7104 declare ppc_fp128 @llvm.exp.ppcf128(ppc_fp128 %Val)
7105</pre>
7106
7107<h5>Overview:</h5>
7108<p>The '<tt>llvm.exp.*</tt>' intrinsics perform the exp function.</p>
7109
7110<h5>Arguments:</h5>
7111<p>The argument and return value are floating point numbers of the same
7112 type.</p>
7113
7114<h5>Semantics:</h5>
7115<p>This function returns the same values as the libm <tt>exp</tt> functions
7116 would, and handles error conditions in the same way.</p>
7117
7118</div>
7119
7120<!-- _______________________________________________________________________ -->
7121<h4>
7122 <a name="int_log">'<tt>llvm.log.*</tt>' Intrinsic</a>
7123</h4>
7124
7125<div>
7126
7127<h5>Syntax:</h5>
7128<p>This is an overloaded intrinsic. You can use <tt>llvm.log</tt> on any
7129 floating point or vector of floating point type. Not all targets support all
7130 types however.</p>
7131
7132<pre>
7133 declare float @llvm.log.f32(float %Val)
7134 declare double @llvm.log.f64(double %Val)
7135 declare x86_fp80 @llvm.log.f80(x86_fp80 %Val)
7136 declare fp128 @llvm.log.f128(fp128 %Val)
7137 declare ppc_fp128 @llvm.log.ppcf128(ppc_fp128 %Val)
7138</pre>
7139
7140<h5>Overview:</h5>
7141<p>The '<tt>llvm.log.*</tt>' intrinsics perform the log function.</p>
7142
7143<h5>Arguments:</h5>
7144<p>The argument and return value are floating point numbers of the same
7145 type.</p>
7146
7147<h5>Semantics:</h5>
7148<p>This function returns the same values as the libm <tt>log</tt> functions
7149 would, and handles error conditions in the same way.</p>
7150
Nick Lewycky1c929be2011-10-31 01:32:21 +0000[diff] [blame]7151</div>
7152
7153<!-- _______________________________________________________________________ -->
Cameron Zwarich33390842011-07-08 21:39:21 +0000[diff] [blame]7154<h4>
7155 <a name="int_fma">'<tt>llvm.fma.*</tt>' Intrinsic</a>
7156</h4>
7157
7158<div>
7159
7160<h5>Syntax:</h5>
7161<p>This is an overloaded intrinsic. You can use <tt>llvm.fma</tt> on any
7162 floating point or vector of floating point type. Not all targets support all
7163 types however.</p>
7164
7165<pre>
7166 declare float @llvm.fma.f32(float %a, float %b, float %c)
7167 declare double @llvm.fma.f64(double %a, double %b, double %c)
7168 declare x86_fp80 @llvm.fma.f80(x86_fp80 %a, x86_fp80 %b, x86_fp80 %c)
7169 declare fp128 @llvm.fma.f128(fp128 %a, fp128 %b, fp128 %c)
7170 declare ppc_fp128 @llvm.fma.ppcf128(ppc_fp128 %a, ppc_fp128 %b, ppc_fp128 %c)
7171</pre>
7172
7173<h5>Overview:</h5>
Cameron Zwarichabc43e62011-07-08 22:13:55 +0000[diff] [blame]7174<p>The '<tt>llvm.fma.*</tt>' intrinsics perform the fused multiply-add
Cameron Zwarich33390842011-07-08 21:39:21 +0000[diff] [blame]7175 operation.</p>
7176
7177<h5>Arguments:</h5>
7178<p>The argument and return value are floating point numbers of the same
7179 type.</p>
7180
7181<h5>Semantics:</h5>
7182<p>This function returns the same values as the libm <tt>fma</tt> functions
7183 would.</p>
7184
Dan Gohman4e9011c2011-05-23 21:13:03 +0000[diff] [blame]7185</div>
7186
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7187<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7188<h3>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]7189 <a name="int_manip">Bit Manipulation Intrinsics</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7190</h3>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7191
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7192<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7193
7194<p>LLVM provides intrinsics for a few important bit manipulation operations.
7195 These allow efficient code generation for some algorithms.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7196
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7197<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7198<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]7199 <a name="int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7200</h4>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]7201
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7202<div>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]7203
7204<h5>Syntax:</h5>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]7205<p>This is an overloaded intrinsic function. You can use bswap on any integer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7206 type that is an even number of bytes (i.e. BitWidth % 16 == 0).</p>
7207
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]7208<pre>
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]7209 declare i16 @llvm.bswap.i16(i16 &lt;id&gt;)
7210 declare i32 @llvm.bswap.i32(i32 &lt;id&gt;)
7211 declare i64 @llvm.bswap.i64(i64 &lt;id&gt;)
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]7212</pre>
7213
7214<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7215<p>The '<tt>llvm.bswap</tt>' family of intrinsics is used to byte swap integer
7216 values with an even number of bytes (positive multiple of 16 bits). These
7217 are useful for performing operations on data that is not in the target's
7218 native byte order.</p>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]7219
7220<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7221<p>The <tt>llvm.bswap.i16</tt> intrinsic returns an i16 value that has the high
7222 and low byte of the input i16 swapped. Similarly,
7223 the <tt>llvm.bswap.i32</tt> intrinsic returns an i32 value that has the four
7224 bytes of the input i32 swapped, so that if the input bytes are numbered 0, 1,
7225 2, 3 then the returned i32 will have its bytes in 3, 2, 1, 0 order.
7226 The <tt>llvm.bswap.i48</tt>, <tt>llvm.bswap.i64</tt> and other intrinsics
7227 extend this concept to additional even-byte lengths (6 bytes, 8 bytes and
7228 more, respectively).</p>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]7229
7230</div>
7231
7232<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7233<h4>
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]7234 <a name="int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7235</h4>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7236
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7237<div>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7238
7239<h5>Syntax:</h5>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]7240<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]7241 width, or on any vector with integer elements. Not all targets support all
7242 bit widths or vector types, however.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7243
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7244<pre>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7245 declare i8 @llvm.ctpop.i8(i8 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]7246 declare i16 @llvm.ctpop.i16(i16 &lt;src&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]7247 declare i32 @llvm.ctpop.i32(i32 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]7248 declare i64 @llvm.ctpop.i64(i64 &lt;src&gt;)
7249 declare i256 @llvm.ctpop.i256(i256 &lt;src&gt;)
Owen Andersonf1ac4652011-07-01 21:52:38 +0000[diff] [blame]7250 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]7251</pre>
7252
7253<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7254<p>The '<tt>llvm.ctpop</tt>' family of intrinsics counts the number of bits set
7255 in a value.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7256
7257<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7258<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]7259 integer type, or a vector with integer elements.
7260 The return type must match the argument type.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7261
7262<h5>Semantics:</h5>
Owen Andersonf1ac4652011-07-01 21:52:38 +0000[diff] [blame]7263<p>The '<tt>llvm.ctpop</tt>' intrinsic counts the 1's in a variable, or within each
7264 element of a vector.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7265
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7266</div>
7267
7268<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7269<h4>
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]7270 <a name="int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7271</h4>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7272
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7273<div>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7274
7275<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7276<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]7277 integer bit width, or any vector whose elements are integers. Not all
7278 targets support all bit widths or vector types, however.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7279
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7280<pre>
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]7281 declare i8 @llvm.ctlz.i8 (i8 &lt;src&gt;)
7282 declare i16 @llvm.ctlz.i16(i16 &lt;src&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]7283 declare i32 @llvm.ctlz.i32(i32 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]7284 declare i64 @llvm.ctlz.i64(i64 &lt;src&gt;)
7285 declare i256 @llvm.ctlz.i256(i256 &lt;src&gt;)
Owen Andersonf1ac4652011-07-01 21:52:38 +0000[diff] [blame]7286 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]7287</pre>
7288
7289<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7290<p>The '<tt>llvm.ctlz</tt>' family of intrinsic functions counts the number of
7291 leading zeros in a variable.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7292
7293<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7294<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]7295 integer type, or any vector type with integer element type.
7296 The return type must match the argument type.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7297
7298<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7299<p>The '<tt>llvm.ctlz</tt>' intrinsic counts the leading (most significant)
Owen Andersonf1ac4652011-07-01 21:52:38 +0000[diff] [blame]7300 zeros in a variable, or within each element of the vector if the operation
7301 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]7302 the type of src. For example, <tt>llvm.ctlz(i32 2) = 30</tt>.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7303
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7304</div>
Chris Lattner32006282004-06-11 02:28:03 +0000[diff] [blame]7305
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]7306<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7307<h4>
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]7308 <a name="int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7309</h4>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]7310
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7311<div>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]7312
7313<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7314<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]7315 integer bit width, or any vector of integer elements. Not all targets
7316 support all bit widths or vector types, however.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7317
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]7318<pre>
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]7319 declare i8 @llvm.cttz.i8 (i8 &lt;src&gt;)
7320 declare i16 @llvm.cttz.i16(i16 &lt;src&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]7321 declare i32 @llvm.cttz.i32(i32 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]7322 declare i64 @llvm.cttz.i64(i64 &lt;src&gt;)
7323 declare i256 @llvm.cttz.i256(i256 &lt;src&gt;)
Owen Andersonf1ac4652011-07-01 21:52:38 +0000[diff] [blame]7324 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]7325</pre>
7326
7327<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7328<p>The '<tt>llvm.cttz</tt>' family of intrinsic functions counts the number of
7329 trailing zeros.</p>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]7330
7331<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7332<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]7333 integer type, or a vectory with integer element type.. The return type
7334 must match the argument type.</p>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]7335
7336<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7337<p>The '<tt>llvm.cttz</tt>' intrinsic counts the trailing (least significant)
Owen Andersonf1ac4652011-07-01 21:52:38 +0000[diff] [blame]7338 zeros in a variable, or within each element of a vector.
7339 If the src == 0 then the result is the size in bits of
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7340 the type of src. For example, <tt>llvm.cttz(2) = 1</tt>.</p>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]7341
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]7342</div>
7343
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7344</div>
7345
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]7346<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7347<h3>
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]7348 <a name="int_overflow">Arithmetic with Overflow Intrinsics</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7349</h3>
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]7350
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7351<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7352
7353<p>LLVM provides intrinsics for some arithmetic with overflow operations.</p>
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]7354
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7355<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7356<h4>
7357 <a name="int_sadd_overflow">
7358 '<tt>llvm.sadd.with.overflow.*</tt>' Intrinsics
7359 </a>
7360</h4>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7361
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7362<div>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7363
7364<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7365<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]7366 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7367
7368<pre>
7369 declare {i16, i1} @llvm.sadd.with.overflow.i16(i16 %a, i16 %b)
7370 declare {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
7371 declare {i64, i1} @llvm.sadd.with.overflow.i64(i64 %a, i64 %b)
7372</pre>
7373
7374<h5>Overview:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7375<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7376 a signed addition of the two arguments, and indicate whether an overflow
7377 occurred during the signed summation.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7378
7379<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7380<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]7381 be of integer types of any bit width, but they must have the same bit
7382 width. The second element of the result structure must be of
7383 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
7384 undergo signed addition.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7385
7386<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7387<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7388 a signed addition of the two variables. They return a structure &mdash; the
7389 first element of which is the signed summation, and the second element of
7390 which is a bit specifying if the signed summation resulted in an
7391 overflow.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7392
7393<h5>Examples:</h5>
7394<pre>
7395 %res = call {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
7396 %sum = extractvalue {i32, i1} %res, 0
7397 %obit = extractvalue {i32, i1} %res, 1
7398 br i1 %obit, label %overflow, label %normal
7399</pre>
7400
7401</div>
7402
7403<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7404<h4>
7405 <a name="int_uadd_overflow">
7406 '<tt>llvm.uadd.with.overflow.*</tt>' Intrinsics
7407 </a>
7408</h4>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7409
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7410<div>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7411
7412<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7413<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]7414 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7415
7416<pre>
7417 declare {i16, i1} @llvm.uadd.with.overflow.i16(i16 %a, i16 %b)
7418 declare {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
7419 declare {i64, i1} @llvm.uadd.with.overflow.i64(i64 %a, i64 %b)
7420</pre>
7421
7422<h5>Overview:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7423<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7424 an unsigned addition of the two arguments, and indicate whether a carry
7425 occurred during the unsigned summation.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7426
7427<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7428<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]7429 be of integer types of any bit width, but they must have the same bit
7430 width. The second element of the result structure must be of
7431 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
7432 undergo unsigned addition.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7433
7434<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7435<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7436 an unsigned addition of the two arguments. They return a structure &mdash;
7437 the first element of which is the sum, and the second element of which is a
7438 bit specifying if the unsigned summation resulted in a carry.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7439
7440<h5>Examples:</h5>
7441<pre>
7442 %res = call {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
7443 %sum = extractvalue {i32, i1} %res, 0
7444 %obit = extractvalue {i32, i1} %res, 1
7445 br i1 %obit, label %carry, label %normal
7446</pre>
7447
7448</div>
7449
7450<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7451<h4>
7452 <a name="int_ssub_overflow">
7453 '<tt>llvm.ssub.with.overflow.*</tt>' Intrinsics
7454 </a>
7455</h4>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7456
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7457<div>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7458
7459<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7460<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]7461 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7462
7463<pre>
7464 declare {i16, i1} @llvm.ssub.with.overflow.i16(i16 %a, i16 %b)
7465 declare {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
7466 declare {i64, i1} @llvm.ssub.with.overflow.i64(i64 %a, i64 %b)
7467</pre>
7468
7469<h5>Overview:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7470<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7471 a signed subtraction of the two arguments, and indicate whether an overflow
7472 occurred during the signed subtraction.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7473
7474<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7475<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]7476 be of integer types of any bit width, but they must have the same bit
7477 width. The second element of the result structure must be of
7478 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
7479 undergo signed subtraction.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7480
7481<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7482<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7483 a signed subtraction of the two arguments. They return a structure &mdash;
7484 the first element of which is the subtraction, and the second element of
7485 which is a bit specifying if the signed subtraction resulted in an
7486 overflow.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7487
7488<h5>Examples:</h5>
7489<pre>
7490 %res = call {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
7491 %sum = extractvalue {i32, i1} %res, 0
7492 %obit = extractvalue {i32, i1} %res, 1
7493 br i1 %obit, label %overflow, label %normal
7494</pre>
7495
7496</div>
7497
7498<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7499<h4>
7500 <a name="int_usub_overflow">
7501 '<tt>llvm.usub.with.overflow.*</tt>' Intrinsics
7502 </a>
7503</h4>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7504
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7505<div>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7506
7507<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7508<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]7509 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7510
7511<pre>
7512 declare {i16, i1} @llvm.usub.with.overflow.i16(i16 %a, i16 %b)
7513 declare {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
7514 declare {i64, i1} @llvm.usub.with.overflow.i64(i64 %a, i64 %b)
7515</pre>
7516
7517<h5>Overview:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7518<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7519 an unsigned subtraction of the two arguments, and indicate whether an
7520 overflow occurred during the unsigned subtraction.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7521
7522<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7523<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]7524 be of integer types of any bit width, but they must have the same bit
7525 width. The second element of the result structure must be of
7526 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
7527 undergo unsigned subtraction.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7528
7529<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7530<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7531 an unsigned subtraction of the two arguments. They return a structure &mdash;
7532 the first element of which is the subtraction, and the second element of
7533 which is a bit specifying if the unsigned subtraction resulted in an
7534 overflow.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7535
7536<h5>Examples:</h5>
7537<pre>
7538 %res = call {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
7539 %sum = extractvalue {i32, i1} %res, 0
7540 %obit = extractvalue {i32, i1} %res, 1
7541 br i1 %obit, label %overflow, label %normal
7542</pre>
7543
7544</div>
7545
7546<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7547<h4>
7548 <a name="int_smul_overflow">
7549 '<tt>llvm.smul.with.overflow.*</tt>' Intrinsics
7550 </a>
7551</h4>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7552
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7553<div>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7554
7555<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7556<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]7557 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7558
7559<pre>
7560 declare {i16, i1} @llvm.smul.with.overflow.i16(i16 %a, i16 %b)
7561 declare {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
7562 declare {i64, i1} @llvm.smul.with.overflow.i64(i64 %a, i64 %b)
7563</pre>
7564
7565<h5>Overview:</h5>
7566
7567<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7568 a signed multiplication of the two arguments, and indicate whether an
7569 overflow occurred during the signed multiplication.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7570
7571<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7572<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]7573 be of integer types of any bit width, but they must have the same bit
7574 width. The second element of the result structure must be of
7575 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
7576 undergo signed multiplication.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7577
7578<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7579<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7580 a signed multiplication of the two arguments. They return a structure &mdash;
7581 the first element of which is the multiplication, and the second element of
7582 which is a bit specifying if the signed multiplication resulted in an
7583 overflow.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7584
7585<h5>Examples:</h5>
7586<pre>
7587 %res = call {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
7588 %sum = extractvalue {i32, i1} %res, 0
7589 %obit = extractvalue {i32, i1} %res, 1
7590 br i1 %obit, label %overflow, label %normal
7591</pre>
7592
Reid Spencerf86037f2007-04-11 23:23:49 +0000[diff] [blame]7593</div>
7594
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]7595<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7596<h4>
7597 <a name="int_umul_overflow">
7598 '<tt>llvm.umul.with.overflow.*</tt>' Intrinsics
7599 </a>
7600</h4>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]7601
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7602<div>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]7603
7604<h5>Syntax:</h5>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]7605<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]7606 on any integer bit width.</p>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]7607
7608<pre>
7609 declare {i16, i1} @llvm.umul.with.overflow.i16(i16 %a, i16 %b)
7610 declare {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
7611 declare {i64, i1} @llvm.umul.with.overflow.i64(i64 %a, i64 %b)
7612</pre>
7613
7614<h5>Overview:</h5>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]7615<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7616 a unsigned multiplication of the two arguments, and indicate whether an
7617 overflow occurred during the unsigned multiplication.</p>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]7618
7619<h5>Arguments:</h5>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]7620<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]7621 be of integer types of any bit width, but they must have the same bit
7622 width. The second element of the result structure must be of
7623 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
7624 undergo unsigned multiplication.</p>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]7625
7626<h5>Semantics:</h5>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]7627<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7628 an unsigned multiplication of the two arguments. They return a structure
7629 &mdash; the first element of which is the multiplication, and the second
7630 element of which is a bit specifying if the unsigned multiplication resulted
7631 in an overflow.</p>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]7632
7633<h5>Examples:</h5>
7634<pre>
7635 %res = call {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
7636 %sum = extractvalue {i32, i1} %res, 0
7637 %obit = extractvalue {i32, i1} %res, 1
7638 br i1 %obit, label %overflow, label %normal
7639</pre>
7640
7641</div>
7642
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7643</div>
7644
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]7645<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7646<h3>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]7647 <a name="int_fp16">Half Precision Floating Point Intrinsics</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7648</h3>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]7649
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7650<div>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]7651
Chris Lattner0cec9c82010-03-15 04:12:21 +0000[diff] [blame]7652<p>Half precision floating point is a storage-only format. This means that it is
7653 a dense encoding (in memory) but does not support computation in the
7654 format.</p>
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]7655
Chris Lattner0cec9c82010-03-15 04:12:21 +0000[diff] [blame]7656<p>This means that code must first load the half-precision floating point
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]7657 value as an i16, then convert it to float with <a
7658 href="#int_convert_from_fp16"><tt>llvm.convert.from.fp16</tt></a>.
7659 Computation can then be performed on the float value (including extending to
Chris Lattner0cec9c82010-03-15 04:12:21 +0000[diff] [blame]7660 double etc). To store the value back to memory, it is first converted to
7661 float if needed, then converted to i16 with
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]7662 <a href="#int_convert_to_fp16"><tt>llvm.convert.to.fp16</tt></a>, then
7663 storing as an i16 value.</p>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]7664
7665<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7666<h4>
7667 <a name="int_convert_to_fp16">
7668 '<tt>llvm.convert.to.fp16</tt>' Intrinsic
7669 </a>
7670</h4>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]7671
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7672<div>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]7673
7674<h5>Syntax:</h5>
7675<pre>
7676 declare i16 @llvm.convert.to.fp16(f32 %a)
7677</pre>
7678
7679<h5>Overview:</h5>
7680<p>The '<tt>llvm.convert.to.fp16</tt>' intrinsic function performs
7681 a conversion from single precision floating point format to half precision
7682 floating point format.</p>
7683
7684<h5>Arguments:</h5>
7685<p>The intrinsic function contains single argument - the value to be
7686 converted.</p>
7687
7688<h5>Semantics:</h5>
7689<p>The '<tt>llvm.convert.to.fp16</tt>' intrinsic function performs
7690 a conversion from single precision floating point format to half precision
Chris Lattner0cec9c82010-03-15 04:12:21 +0000[diff] [blame]7691 floating point format. The return value is an <tt>i16</tt> which
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]7692 contains the converted number.</p>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]7693
7694<h5>Examples:</h5>
7695<pre>
7696 %res = call i16 @llvm.convert.to.fp16(f32 %a)
7697 store i16 %res, i16* @x, align 2
7698</pre>
7699
7700</div>
7701
7702<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7703<h4>
7704 <a name="int_convert_from_fp16">
7705 '<tt>llvm.convert.from.fp16</tt>' Intrinsic
7706 </a>
7707</h4>
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
7711<h5>Syntax:</h5>
7712<pre>
7713 declare f32 @llvm.convert.from.fp16(i16 %a)
7714</pre>
7715
7716<h5>Overview:</h5>
7717<p>The '<tt>llvm.convert.from.fp16</tt>' intrinsic function performs
7718 a conversion from half precision floating point format to single precision
7719 floating point format.</p>
7720
7721<h5>Arguments:</h5>
7722<p>The intrinsic function contains single argument - the value to be
7723 converted.</p>
7724
7725<h5>Semantics:</h5>
7726<p>The '<tt>llvm.convert.from.fp16</tt>' intrinsic function performs a
Chris Lattner0cec9c82010-03-15 04:12:21 +0000[diff] [blame]7727 conversion from half single precision floating point format to single
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]7728 precision floating point format. The input half-float value is represented by
7729 an <tt>i16</tt> value.</p>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]7730
7731<h5>Examples:</h5>
7732<pre>
7733 %a = load i16* @x, align 2
7734 %res = call f32 @llvm.convert.from.fp16(i16 %a)
7735</pre>
7736
7737</div>
7738
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7739</div>
7740
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]7741<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7742<h3>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]7743 <a name="int_debugger">Debugger Intrinsics</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7744</h3>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]7745
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7746<div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]7747
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7748<p>The LLVM debugger intrinsics (which all start with <tt>llvm.dbg.</tt>
7749 prefix), are described in
7750 the <a href="SourceLevelDebugging.html#format_common_intrinsics">LLVM Source
7751 Level Debugging</a> document.</p>
7752
7753</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]7754
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]7755<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7756<h3>
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]7757 <a name="int_eh">Exception Handling Intrinsics</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7758</h3>
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]7759
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7760<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7761
7762<p>The LLVM exception handling intrinsics (which all start with
7763 <tt>llvm.eh.</tt> prefix), are described in
7764 the <a href="ExceptionHandling.html#format_common_intrinsics">LLVM Exception
7765 Handling</a> document.</p>
7766
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]7767</div>
7768
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]7769<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7770<h3>
Duncan Sands4a544a72011-09-06 13:37:06 +0000[diff] [blame]7771 <a name="int_trampoline">Trampoline Intrinsics</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7772</h3>
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]7773
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7774<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7775
Duncan Sands4a544a72011-09-06 13:37:06 +0000[diff] [blame]7776<p>These intrinsics make it possible to excise one parameter, marked with
Dan Gohmanff235352010-07-02 23:18:08 +0000[diff] [blame]7777 the <a href="#nest"><tt>nest</tt></a> attribute, from a function.
7778 The result is a callable
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7779 function pointer lacking the nest parameter - the caller does not need to
7780 provide a value for it. Instead, the value to use is stored in advance in a
7781 "trampoline", a block of memory usually allocated on the stack, which also
7782 contains code to splice the nest value into the argument list. This is used
7783 to implement the GCC nested function address extension.</p>
7784
7785<p>For example, if the function is
7786 <tt>i32 f(i8* nest %c, i32 %x, i32 %y)</tt> then the resulting function
7787 pointer has signature <tt>i32 (i32, i32)*</tt>. It can be created as
7788 follows:</p>
7789
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]7790<pre class="doc_code">
Duncan Sandsf7331b32007-09-11 14:10:23 +0000[diff] [blame]7791 %tramp = alloca [10 x i8], align 4 ; size and alignment only correct for X86
7792 %tramp1 = getelementptr [10 x i8]* %tramp, i32 0, i32 0
Duncan Sands4a544a72011-09-06 13:37:06 +0000[diff] [blame]7793 call i8* @llvm.init.trampoline(i8* %tramp1, i8* bitcast (i32 (i8*, i32, i32)* @f to i8*), i8* %nval)
7794 %p = call i8* @llvm.adjust.trampoline(i8* %tramp1)
Duncan Sandsf7331b32007-09-11 14:10:23 +0000[diff] [blame]7795 %fp = bitcast i8* %p to i32 (i32, i32)*
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]7796</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7797
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7798<p>The call <tt>%val = call i32 %fp(i32 %x, i32 %y)</tt> is then equivalent
7799 to <tt>%val = call i32 %f(i8* %nval, i32 %x, i32 %y)</tt>.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7800
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]7801<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7802<h4>
7803 <a name="int_it">
7804 '<tt>llvm.init.trampoline</tt>' Intrinsic
7805 </a>
7806</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7807
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7808<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7809
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]7810<h5>Syntax:</h5>
7811<pre>
Duncan Sands4a544a72011-09-06 13:37:06 +0000[diff] [blame]7812 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]7813</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7814
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]7815<h5>Overview:</h5>
Duncan Sands4a544a72011-09-06 13:37:06 +0000[diff] [blame]7816<p>This fills the memory pointed to by <tt>tramp</tt> with executable code,
7817 turning it into a trampoline.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7818
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]7819<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7820<p>The <tt>llvm.init.trampoline</tt> intrinsic takes three arguments, all
7821 pointers. The <tt>tramp</tt> argument must point to a sufficiently large and
7822 sufficiently aligned block of memory; this memory is written to by the
7823 intrinsic. Note that the size and the alignment are target-specific - LLVM
7824 currently provides no portable way of determining them, so a front-end that
7825 generates this intrinsic needs to have some target-specific knowledge.
7826 The <tt>func</tt> argument must hold a function bitcast to
7827 an <tt>i8*</tt>.</p>
7828
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]7829<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7830<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]7831 dependent code, turning it into a function. Then <tt>tramp</tt> needs to be
7832 passed to <a href="#int_at">llvm.adjust.trampoline</a> to get a pointer
7833 which can be <a href="#int_trampoline">bitcast (to a new function) and
7834 called</a>. The new function's signature is the same as that of
7835 <tt>func</tt> with any arguments marked with the <tt>nest</tt> attribute
7836 removed. At most one such <tt>nest</tt> argument is allowed, and it must be of
7837 pointer type. Calling the new function is equivalent to calling <tt>func</tt>
7838 with the same argument list, but with <tt>nval</tt> used for the missing
7839 <tt>nest</tt> argument. If, after calling <tt>llvm.init.trampoline</tt>, the
7840 memory pointed to by <tt>tramp</tt> is modified, then the effect of any later call
7841 to the returned function pointer is undefined.</p>
7842</div>
7843
7844<!-- _______________________________________________________________________ -->
7845<h4>
7846 <a name="int_at">
7847 '<tt>llvm.adjust.trampoline</tt>' Intrinsic
7848 </a>
7849</h4>
7850
7851<div>
7852
7853<h5>Syntax:</h5>
7854<pre>
7855 declare i8* @llvm.adjust.trampoline(i8* &lt;tramp&gt;)
7856</pre>
7857
7858<h5>Overview:</h5>
7859<p>This performs any required machine-specific adjustment to the address of a
7860 trampoline (passed as <tt>tramp</tt>).</p>
7861
7862<h5>Arguments:</h5>
7863<p><tt>tramp</tt> must point to a block of memory which already has trampoline code
7864 filled in by a previous call to <a href="#int_it"><tt>llvm.init.trampoline</tt>
7865 </a>.</p>
7866
7867<h5>Semantics:</h5>
7868<p>On some architectures the address of the code to be executed needs to be
7869 different to the address where the trampoline is actually stored. This
7870 intrinsic returns the executable address corresponding to <tt>tramp</tt>
7871 after performing the required machine specific adjustments.
7872 The pointer returned can then be <a href="#int_trampoline"> bitcast and
7873 executed</a>.
7874</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7875
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]7876</div>
7877
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7878</div>
7879
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]7880<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7881<h3>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7882 <a name="int_memorymarkers">Memory Use Markers</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7883</h3>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7884
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7885<div>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7886
7887<p>This class of intrinsics exists to information about the lifetime of memory
7888 objects and ranges where variables are immutable.</p>
7889
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7890<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7891<h4>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7892 <a name="int_lifetime_start">'<tt>llvm.lifetime.start</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7893</h4>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7894
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7895<div>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7896
7897<h5>Syntax:</h5>
7898<pre>
7899 declare void @llvm.lifetime.start(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7900</pre>
7901
7902<h5>Overview:</h5>
7903<p>The '<tt>llvm.lifetime.start</tt>' intrinsic specifies the start of a memory
7904 object's lifetime.</p>
7905
7906<h5>Arguments:</h5>
Nick Lewycky321333e2009-10-13 07:57:33 +0000[diff] [blame]7907<p>The first argument is a constant integer representing the size of the
7908 object, or -1 if it is variable sized. The second argument is a pointer to
7909 the object.</p>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7910
7911<h5>Semantics:</h5>
7912<p>This intrinsic indicates that before this point in the code, the value of the
7913 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]7914 never be used and has an undefined value. A load from the pointer that
7915 precedes this intrinsic can be replaced with
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7916 <tt>'<a href="#undefvalues">undef</a>'</tt>.</p>
7917
7918</div>
7919
7920<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7921<h4>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7922 <a name="int_lifetime_end">'<tt>llvm.lifetime.end</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7923</h4>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7924
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7925<div>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7926
7927<h5>Syntax:</h5>
7928<pre>
7929 declare void @llvm.lifetime.end(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7930</pre>
7931
7932<h5>Overview:</h5>
7933<p>The '<tt>llvm.lifetime.end</tt>' intrinsic specifies the end of a memory
7934 object's lifetime.</p>
7935
7936<h5>Arguments:</h5>
Nick Lewycky321333e2009-10-13 07:57:33 +0000[diff] [blame]7937<p>The first argument is a constant integer representing the size of the
7938 object, or -1 if it is variable sized. The second argument is a pointer to
7939 the object.</p>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7940
7941<h5>Semantics:</h5>
7942<p>This intrinsic indicates that after this point in the code, the value of the
7943 memory pointed to by <tt>ptr</tt> is dead. This means that it is known to
7944 never be used and has an undefined value. Any stores into the memory object
7945 following this intrinsic may be removed as dead.
7946
7947</div>
7948
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_invariant_start">'<tt>llvm.invariant.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>
Nick Lewycky29b6cb42010-11-30 04:13:41 +0000[diff] [blame]7958 declare {}* @llvm.invariant.start(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7959</pre>
7960
7961<h5>Overview:</h5>
7962<p>The '<tt>llvm.invariant.start</tt>' intrinsic specifies that the contents of
7963 a memory object will not change.</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 until an <tt>llvm.invariant.end</tt> that uses
7972 the return value, the referenced memory location is constant and
7973 unchanging.</p>
7974
7975</div>
7976
7977<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7978<h4>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7979 <a name="int_invariant_end">'<tt>llvm.invariant.end</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7980</h4>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7981
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7982<div>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7983
7984<h5>Syntax:</h5>
7985<pre>
7986 declare void @llvm.invariant.end({}* &lt;start&gt;, i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7987</pre>
7988
7989<h5>Overview:</h5>
7990<p>The '<tt>llvm.invariant.end</tt>' intrinsic specifies that the contents of
7991 a memory object are mutable.</p>
7992
7993<h5>Arguments:</h5>
7994<p>The first argument is the matching <tt>llvm.invariant.start</tt> intrinsic.
Nick Lewycky321333e2009-10-13 07:57:33 +0000[diff] [blame]7995 The second argument is a constant integer representing the size of the
7996 object, or -1 if it is variable sized and the third argument is a pointer
7997 to the object.</p>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7998
7999<h5>Semantics:</h5>
8000<p>This intrinsic indicates that the memory is mutable again.</p>
8001
8002</div>
8003
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8004</div>
8005
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]8006<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8007<h3>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]8008 <a name="int_general">General Intrinsics</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8009</h3>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]8010
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8011<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8012
8013<p>This class of intrinsics is designed to be generic and has no specific
8014 purpose.</p>
8015
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]8016<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8017<h4>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]8018 <a name="int_var_annotation">'<tt>llvm.var.annotation</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8019</h4>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]8020
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8021<div>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]8022
8023<h5>Syntax:</h5>
8024<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]8025 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]8026</pre>
8027
8028<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8029<p>The '<tt>llvm.var.annotation</tt>' intrinsic.</p>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]8030
8031<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8032<p>The first argument is a pointer to a value, the second is a pointer to a
8033 global string, the third is a pointer to a global string which is the source
8034 file name, and the last argument is the line number.</p>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]8035
8036<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8037<p>This intrinsic allows annotation of local variables with arbitrary strings.
8038 This can be useful for special purpose optimizations that want to look for
John Criswelle865c032011-08-19 16:57:55 +0000[diff] [blame]8039 these annotations. These have no other defined use; they are ignored by code
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8040 generation and optimization.</p>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]8041
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]8042</div>
8043
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]8044<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8045<h4>
Tanya Lattnere1a8da02007-09-21 23:57:59 +0000[diff] [blame]8046 <a name="int_annotation">'<tt>llvm.annotation.*</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8047</h4>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]8048
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8049<div>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]8050
8051<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8052<p>This is an overloaded intrinsic. You can use '<tt>llvm.annotation</tt>' on
8053 any integer bit width.</p>
8054
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]8055<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]8056 declare i8 @llvm.annotation.i8(i8 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
8057 declare i16 @llvm.annotation.i16(i16 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
8058 declare i32 @llvm.annotation.i32(i32 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
8059 declare i64 @llvm.annotation.i64(i64 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
8060 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]8061</pre>
8062
8063<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8064<p>The '<tt>llvm.annotation</tt>' intrinsic.</p>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]8065
8066<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8067<p>The first argument is an integer value (result of some expression), the
8068 second is a pointer to a global string, the third is a pointer to a global
8069 string which is the source file name, and the last argument is the line
8070 number. It returns the value of the first argument.</p>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]8071
8072<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8073<p>This intrinsic allows annotations to be put on arbitrary expressions with
8074 arbitrary strings. This can be useful for special purpose optimizations that
John Criswelle865c032011-08-19 16:57:55 +0000[diff] [blame]8075 want to look for these annotations. These have no other defined use; they
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8076 are ignored by code generation and optimization.</p>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]8077
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]8078</div>
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]8079
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]8080<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8081<h4>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]8082 <a name="int_trap">'<tt>llvm.trap</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8083</h4>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]8084
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8085<div>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]8086
8087<h5>Syntax:</h5>
8088<pre>
8089 declare void @llvm.trap()
8090</pre>
8091
8092<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8093<p>The '<tt>llvm.trap</tt>' intrinsic.</p>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]8094
8095<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8096<p>None.</p>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]8097
8098<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8099<p>This intrinsics is lowered to the target dependent trap instruction. If the
8100 target does not have a trap instruction, this intrinsic will be lowered to
8101 the call of the <tt>abort()</tt> function.</p>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]8102
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]8103</div>
8104
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]8105<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8106<h4>
Misha Brukmandccb0252008-11-22 23:55:29 +0000[diff] [blame]8107 <a name="int_stackprotector">'<tt>llvm.stackprotector</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8108</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8109
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8110<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8111
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]8112<h5>Syntax:</h5>
8113<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]8114 declare void @llvm.stackprotector(i8* &lt;guard&gt;, i8** &lt;slot&gt;)
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]8115</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8116
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]8117<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8118<p>The <tt>llvm.stackprotector</tt> intrinsic takes the <tt>guard</tt> and
8119 stores it onto the stack at <tt>slot</tt>. The stack slot is adjusted to
8120 ensure that it is placed on the stack before local variables.</p>
8121
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]8122<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8123<p>The <tt>llvm.stackprotector</tt> intrinsic requires two pointer
8124 arguments. The first argument is the value loaded from the stack
8125 guard <tt>@__stack_chk_guard</tt>. The second variable is an <tt>alloca</tt>
8126 that has enough space to hold the value of the guard.</p>
8127
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]8128<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8129<p>This intrinsic causes the prologue/epilogue inserter to force the position of
8130 the <tt>AllocaInst</tt> stack slot to be before local variables on the
8131 stack. This is to ensure that if a local variable on the stack is
8132 overwritten, it will destroy the value of the guard. When the function exits,
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]8133 the guard on the stack is checked against the original guard. If they are
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8134 different, then the program aborts by calling the <tt>__stack_chk_fail()</tt>
8135 function.</p>
8136
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]8137</div>
8138
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]8139<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8140<h4>
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]8141 <a name="int_objectsize">'<tt>llvm.objectsize</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8142</h4>
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]8143
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8144<div>
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]8145
8146<h5>Syntax:</h5>
8147<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]8148 declare i32 @llvm.objectsize.i32(i8* &lt;object&gt;, i1 &lt;type&gt;)
8149 declare i64 @llvm.objectsize.i64(i8* &lt;object&gt;, i1 &lt;type&gt;)
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]8150</pre>
8151
8152<h5>Overview:</h5>
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]8153<p>The <tt>llvm.objectsize</tt> intrinsic is designed to provide information to
8154 the optimizers to determine at compile time whether a) an operation (like
8155 memcpy) will overflow a buffer that corresponds to an object, or b) that a
8156 runtime check for overflow isn't necessary. An object in this context means
8157 an allocation of a specific class, structure, array, or other object.</p>
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]8158
8159<h5>Arguments:</h5>
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]8160<p>The <tt>llvm.objectsize</tt> intrinsic takes two arguments. The first
Eric Christopher8295a0a2009-12-23 00:29:49 +0000[diff] [blame]8161 argument is a pointer to or into the <tt>object</tt>. The second argument
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]8162 is a boolean 0 or 1. This argument determines whether you want the
8163 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]8164 1, variables are not allowed.</p>
8165
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]8166<h5>Semantics:</h5>
8167<p>The <tt>llvm.objectsize</tt> intrinsic is lowered to either a constant
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]8168 representing the size of the object concerned, or <tt>i32/i64 -1 or 0</tt>,
8169 depending on the <tt>type</tt> argument, if the size cannot be determined at
8170 compile time.</p>
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]8171
8172</div>
8173
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8174</div>
8175
8176</div>
8177
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]8178<!-- *********************************************************************** -->
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]8179<hr>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]8180<address>
8181 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
Misha Brukman44408702008-12-11 17:34:48 +0000[diff] [blame]8182 src="http://jigsaw.w3.org/css-validator/images/vcss-blue" alt="Valid CSS"></a>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]8183 <a href="http://validator.w3.org/check/referer"><img
Misha Brukman44408702008-12-11 17:34:48 +0000[diff] [blame]8184 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]8185
8186 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
NAKAMURA Takumib9a33632011-04-09 02:13:37 +0000[diff] [blame]8187 <a href="http://llvm.org/">The LLVM Compiler Infrastructure</a><br>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]8188 Last modified: $Date$
8189</address>
Chris Lattnerc7d3ab32008-01-04 04:33:49 +0000[diff] [blame]8190
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]8191</body>
8192</html>