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gerrit-public.fairphone.software / platform / external / llvm / 5e6162e75645122b6afdbca8ba55294e073dc369 / . / docs / LangRef.html
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5 <title>LLVM Assembly Language Reference Manual</title>
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7 <meta name="author" content="Chris Lattner">
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]8 <meta name="description"
Reid Spencer3921c742004-08-26 20:44:00 +0000[diff] [blame]9 content="LLVM Assembly Language Reference Manual.">
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]10 <link rel="stylesheet" href="llvm.css" type="text/css">
11</head>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]12
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]13<body>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]14
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]15<h1>LLVM Language Reference Manual</h1>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]16<ol>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]17 <li><a href="#abstract">Abstract</a></li>
18 <li><a href="#introduction">Introduction</a></li>
19 <li><a href="#identifiers">Identifiers</a></li>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]20 <li><a href="#highlevel">High Level Structure</a>
21 <ol>
22 <li><a href="#modulestructure">Module Structure</a></li>
Bill Wendling3d10a5a2009-07-20 01:03:30 +0000[diff] [blame]23 <li><a href="#linkage">Linkage Types</a>
24 <ol>
Bill Wendling987e7eb2009-07-20 02:41:50 +0000[diff] [blame]25 <li><a href="#linkage_private">'<tt>private</tt>' Linkage</a></li>
26 <li><a href="#linkage_linker_private">'<tt>linker_private</tt>' Linkage</a></li>
Bill Wendling5e721d72010-07-01 21:55:59 +0000[diff] [blame]27 <li><a href="#linkage_linker_private_weak">'<tt>linker_private_weak</tt>' Linkage</a></li>
Bill Wendling55ae5152010-08-20 22:05:50 +0000[diff] [blame]28 <li><a href="#linkage_linker_private_weak_def_auto">'<tt>linker_private_weak_def_auto</tt>' Linkage</a></li>
Bill Wendling987e7eb2009-07-20 02:41:50 +0000[diff] [blame]29 <li><a href="#linkage_internal">'<tt>internal</tt>' Linkage</a></li>
30 <li><a href="#linkage_available_externally">'<tt>available_externally</tt>' Linkage</a></li>
31 <li><a href="#linkage_linkonce">'<tt>linkonce</tt>' Linkage</a></li>
32 <li><a href="#linkage_common">'<tt>common</tt>' Linkage</a></li>
33 <li><a href="#linkage_weak">'<tt>weak</tt>' Linkage</a></li>
34 <li><a href="#linkage_appending">'<tt>appending</tt>' Linkage</a></li>
35 <li><a href="#linkage_externweak">'<tt>extern_weak</tt>' Linkage</a></li>
Chris Lattner5a2d8752009-10-10 18:26:06 +0000[diff] [blame]36 <li><a href="#linkage_linkonce_odr">'<tt>linkonce_odr</tt>' Linkage</a></li>
Bill Wendling987e7eb2009-07-20 02:41:50 +0000[diff] [blame]37 <li><a href="#linkage_weak">'<tt>weak_odr</tt>' Linkage</a></li>
Bill Wendlingf7f06102011-10-11 06:41:28 +0000[diff] [blame]38 <li><a href="#linkage_external">'<tt>external</tt>' Linkage</a></li>
Bill Wendling987e7eb2009-07-20 02:41:50 +0000[diff] [blame]39 <li><a href="#linkage_dllimport">'<tt>dllimport</tt>' Linkage</a></li>
40 <li><a href="#linkage_dllexport">'<tt>dllexport</tt>' Linkage</a></li>
Bill Wendling3d10a5a2009-07-20 01:03:30 +0000[diff] [blame]41 </ol>
42 </li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]43 <li><a href="#callingconv">Calling Conventions</a></li>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]44 <li><a href="#namedtypes">Named Types</a></li>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]45 <li><a href="#globalvars">Global Variables</a></li>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]46 <li><a href="#functionstructure">Functions</a></li>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]47 <li><a href="#aliasstructure">Aliases</a></li>
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]48 <li><a href="#namedmetadatastructure">Named Metadata</a></li>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]49 <li><a href="#paramattrs">Parameter Attributes</a></li>
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]50 <li><a href="#fnattrs">Function Attributes</a></li>
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]51 <li><a href="#gc">Garbage Collector Names</a></li>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]52 <li><a href="#moduleasm">Module-Level Inline Assembly</a></li>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]53 <li><a href="#datalayout">Data Layout</a></li>
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]54 <li><a href="#pointeraliasing">Pointer Aliasing Rules</a></li>
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]55 <li><a href="#volatile">Volatile Memory Accesses</a></li>
Eli Friedman5b60e1b2011-07-20 21:35:53 +0000[diff] [blame]56 <li><a href="#memmodel">Memory Model for Concurrent Operations</a></li>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]57 <li><a href="#ordering">Atomic Memory Ordering Constraints</a></li>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]58 </ol>
59 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]60 <li><a href="#typesystem">Type System</a>
61 <ol>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]62 <li><a href="#t_classifications">Type Classifications</a></li>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]63 <li><a href="#t_primitive">Primitive Types</a>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]64 <ol>
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]65 <li><a href="#t_integer">Integer Type</a></li>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]66 <li><a href="#t_floating">Floating Point Types</a></li>
Dale Johannesen21fe99b2010-10-01 00:48:59 +0000[diff] [blame]67 <li><a href="#t_x86mmx">X86mmx Type</a></li>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]68 <li><a href="#t_void">Void Type</a></li>
69 <li><a href="#t_label">Label Type</a></li>
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]70 <li><a href="#t_metadata">Metadata Type</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]71 </ol>
72 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]73 <li><a href="#t_derived">Derived Types</a>
74 <ol>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]75 <li><a href="#t_aggregate">Aggregate Types</a>
76 <ol>
77 <li><a href="#t_array">Array Type</a></li>
78 <li><a href="#t_struct">Structure Type</a></li>
Chris Lattner628ed392011-07-23 19:59:08 +0000[diff] [blame]79 <li><a href="#t_opaque">Opaque Structure Types</a></li>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]80 <li><a href="#t_vector">Vector Type</a></li>
81 </ol>
82 </li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]83 <li><a href="#t_function">Function Type</a></li>
84 <li><a href="#t_pointer">Pointer Type</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]85 </ol>
86 </li>
87 </ol>
88 </li>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]89 <li><a href="#constants">Constants</a>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]90 <ol>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]91 <li><a href="#simpleconstants">Simple Constants</a></li>
Chris Lattner70882792009-02-28 18:32:25 +0000[diff] [blame]92 <li><a href="#complexconstants">Complex Constants</a></li>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]93 <li><a href="#globalconstants">Global Variable and Function Addresses</a></li>
94 <li><a href="#undefvalues">Undefined Values</a></li>
Dan Gohmanbfb056d2011-12-06 03:18:47 +0000[diff] [blame]95 <li><a href="#poisonvalues">Poison Values</a></li>
Chris Lattnerf9d078e2009-10-27 21:19:13 +0000[diff] [blame]96 <li><a href="#blockaddress">Addresses of Basic Blocks</a></li>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]97 <li><a href="#constantexprs">Constant Expressions</a></li>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]98 </ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]99 </li>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]100 <li><a href="#othervalues">Other Values</a>
101 <ol>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]102 <li><a href="#inlineasm">Inline Assembler Expressions</a></li>
Peter Collingbourne249d9532011-10-27 19:19:07 +0000[diff] [blame]103 <li><a href="#metadata">Metadata Nodes and Metadata Strings</a>
104 <ol>
105 <li><a href="#tbaa">'<tt>tbaa</tt>' Metadata</a></li>
Peter Collingbourne999f90b2011-10-27 19:19:14 +0000[diff] [blame]106 <li><a href="#fpaccuracy">'<tt>fpaccuracy</tt>' Metadata</a></li>
Peter Collingbourne249d9532011-10-27 19:19:07 +0000[diff] [blame]107 </ol>
108 </li>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]109 </ol>
110 </li>
Bill Wendlingb9d75a92012-02-11 11:59:36 +0000[diff] [blame]111 <li><a href="#module_flags">Module Flags Metadata</a>
112 <ol>
113 </ol>
114 </li>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]115 <li><a href="#intrinsic_globals">Intrinsic Global Variables</a>
116 <ol>
117 <li><a href="#intg_used">The '<tt>llvm.used</tt>' Global Variable</a></li>
Chris Lattner401e10c2009-07-20 06:14:25 +0000[diff] [blame]118 <li><a href="#intg_compiler_used">The '<tt>llvm.compiler.used</tt>'
119 Global Variable</a></li>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]120 <li><a href="#intg_global_ctors">The '<tt>llvm.global_ctors</tt>'
121 Global Variable</a></li>
122 <li><a href="#intg_global_dtors">The '<tt>llvm.global_dtors</tt>'
123 Global Variable</a></li>
124 </ol>
125 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]126 <li><a href="#instref">Instruction Reference</a>
127 <ol>
128 <li><a href="#terminators">Terminator Instructions</a>
129 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]130 <li><a href="#i_ret">'<tt>ret</tt>' Instruction</a></li>
131 <li><a href="#i_br">'<tt>br</tt>' Instruction</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]132 <li><a href="#i_switch">'<tt>switch</tt>' Instruction</a></li>
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]133 <li><a href="#i_indirectbr">'<tt>indirectbr</tt>' Instruction</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]134 <li><a href="#i_invoke">'<tt>invoke</tt>' Instruction</a></li>
Bill Wendlingdccc03b2011-07-31 06:30:59 +0000[diff] [blame]135 <li><a href="#i_resume">'<tt>resume</tt>' Instruction</a></li>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]136 <li><a href="#i_unreachable">'<tt>unreachable</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]137 </ol>
138 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]139 <li><a href="#binaryops">Binary Operations</a>
140 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]141 <li><a href="#i_add">'<tt>add</tt>' Instruction</a></li>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]142 <li><a href="#i_fadd">'<tt>fadd</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]143 <li><a href="#i_sub">'<tt>sub</tt>' Instruction</a></li>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]144 <li><a href="#i_fsub">'<tt>fsub</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]145 <li><a href="#i_mul">'<tt>mul</tt>' Instruction</a></li>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]146 <li><a href="#i_fmul">'<tt>fmul</tt>' Instruction</a></li>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]147 <li><a href="#i_udiv">'<tt>udiv</tt>' Instruction</a></li>
148 <li><a href="#i_sdiv">'<tt>sdiv</tt>' Instruction</a></li>
149 <li><a href="#i_fdiv">'<tt>fdiv</tt>' Instruction</a></li>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]150 <li><a href="#i_urem">'<tt>urem</tt>' Instruction</a></li>
151 <li><a href="#i_srem">'<tt>srem</tt>' Instruction</a></li>
152 <li><a href="#i_frem">'<tt>frem</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]153 </ol>
154 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]155 <li><a href="#bitwiseops">Bitwise Binary Operations</a>
156 <ol>
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]157 <li><a href="#i_shl">'<tt>shl</tt>' Instruction</a></li>
158 <li><a href="#i_lshr">'<tt>lshr</tt>' Instruction</a></li>
159 <li><a href="#i_ashr">'<tt>ashr</tt>' Instruction</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]160 <li><a href="#i_and">'<tt>and</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]161 <li><a href="#i_or">'<tt>or</tt>' Instruction</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]162 <li><a href="#i_xor">'<tt>xor</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]163 </ol>
164 </li>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]165 <li><a href="#vectorops">Vector Operations</a>
166 <ol>
167 <li><a href="#i_extractelement">'<tt>extractelement</tt>' Instruction</a></li>
168 <li><a href="#i_insertelement">'<tt>insertelement</tt>' Instruction</a></li>
169 <li><a href="#i_shufflevector">'<tt>shufflevector</tt>' Instruction</a></li>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]170 </ol>
171 </li>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]172 <li><a href="#aggregateops">Aggregate Operations</a>
173 <ol>
174 <li><a href="#i_extractvalue">'<tt>extractvalue</tt>' Instruction</a></li>
175 <li><a href="#i_insertvalue">'<tt>insertvalue</tt>' Instruction</a></li>
176 </ol>
177 </li>
Chris Lattner884a9702006-08-15 00:45:58 +0000[diff] [blame]178 <li><a href="#memoryops">Memory Access and Addressing Operations</a>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]179 <ol>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]180 <li><a href="#i_alloca">'<tt>alloca</tt>' Instruction</a></li>
181 <li><a href="#i_load">'<tt>load</tt>' Instruction</a></li>
182 <li><a href="#i_store">'<tt>store</tt>' Instruction</a></li>
183 <li><a href="#i_fence">'<tt>fence</tt>' Instruction</a></li>
184 <li><a href="#i_cmpxchg">'<tt>cmpxchg</tt>' Instruction</a></li>
185 <li><a href="#i_atomicrmw">'<tt>atomicrmw</tt>' Instruction</a></li>
Robert Bocchino7b81c752006-02-17 21:18:08 +0000[diff] [blame]186 <li><a href="#i_getelementptr">'<tt>getelementptr</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]187 </ol>
188 </li>
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]189 <li><a href="#convertops">Conversion Operations</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]190 <ol>
191 <li><a href="#i_trunc">'<tt>trunc .. to</tt>' Instruction</a></li>
192 <li><a href="#i_zext">'<tt>zext .. to</tt>' Instruction</a></li>
193 <li><a href="#i_sext">'<tt>sext .. to</tt>' Instruction</a></li>
194 <li><a href="#i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a></li>
195 <li><a href="#i_fpext">'<tt>fpext .. to</tt>' Instruction</a></li>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]196 <li><a href="#i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a></li>
197 <li><a href="#i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a></li>
198 <li><a href="#i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a></li>
199 <li><a href="#i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a></li>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]200 <li><a href="#i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a></li>
201 <li><a href="#i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a></li>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]202 <li><a href="#i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a></li>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]203 </ol>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]204 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]205 <li><a href="#otherops">Other Operations</a>
206 <ol>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]207 <li><a href="#i_icmp">'<tt>icmp</tt>' Instruction</a></li>
208 <li><a href="#i_fcmp">'<tt>fcmp</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]209 <li><a href="#i_phi">'<tt>phi</tt>' Instruction</a></li>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]210 <li><a href="#i_select">'<tt>select</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]211 <li><a href="#i_call">'<tt>call</tt>' Instruction</a></li>
Chris Lattnerfb6977d2006-01-13 23:26:01 +0000[diff] [blame]212 <li><a href="#i_va_arg">'<tt>va_arg</tt>' Instruction</a></li>
Bill Wendlingf78faf82011-08-02 21:52:38 +0000[diff] [blame]213 <li><a href="#i_landingpad">'<tt>landingpad</tt>' Instruction</a></li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]214 </ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]215 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]216 </ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]217 </li>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]218 <li><a href="#intrinsics">Intrinsic Functions</a>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]219 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]220 <li><a href="#int_varargs">Variable Argument Handling Intrinsics</a>
221 <ol>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]222 <li><a href="#int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a></li>
223 <li><a href="#int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a></li>
224 <li><a href="#int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]225 </ol>
226 </li>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]227 <li><a href="#int_gc">Accurate Garbage Collection Intrinsics</a>
228 <ol>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]229 <li><a href="#int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a></li>
230 <li><a href="#int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a></li>
231 <li><a href="#int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a></li>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]232 </ol>
233 </li>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]234 <li><a href="#int_codegen">Code Generator Intrinsics</a>
235 <ol>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]236 <li><a href="#int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a></li>
237 <li><a href="#int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a></li>
238 <li><a href="#int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a></li>
239 <li><a href="#int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a></li>
240 <li><a href="#int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a></li>
241 <li><a href="#int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a></li>
Dan Gohman31f1af12010-05-26 21:56:15 +0000[diff] [blame]242 <li><a href="#int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a></li>
John Criswell7123e272004-04-09 16:43:20 +0000[diff] [blame]243 </ol>
244 </li>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]245 <li><a href="#int_libc">Standard C Library Intrinsics</a>
246 <ol>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]247 <li><a href="#int_memcpy">'<tt>llvm.memcpy.*</tt>' Intrinsic</a></li>
248 <li><a href="#int_memmove">'<tt>llvm.memmove.*</tt>' Intrinsic</a></li>
249 <li><a href="#int_memset">'<tt>llvm.memset.*</tt>' Intrinsic</a></li>
250 <li><a href="#int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a></li>
251 <li><a href="#int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a></li>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]252 <li><a href="#int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a></li>
253 <li><a href="#int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a></li>
254 <li><a href="#int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a></li>
Dan Gohman08b280b2011-05-27 00:36:31 +0000[diff] [blame]255 <li><a href="#int_exp">'<tt>llvm.exp.*</tt>' Intrinsic</a></li>
256 <li><a href="#int_log">'<tt>llvm.log.*</tt>' Intrinsic</a></li>
Cameron Zwarich33390842011-07-08 21:39:21 +0000[diff] [blame]257 <li><a href="#int_fma">'<tt>llvm.fma.*</tt>' Intrinsic</a></li>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]258 </ol>
259 </li>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]260 <li><a href="#int_manip">Bit Manipulation Intrinsics</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]261 <ol>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]262 <li><a href="#int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a></li>
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]263 <li><a href="#int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic </a></li>
264 <li><a href="#int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic </a></li>
265 <li><a href="#int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic </a></li>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]266 </ol>
267 </li>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]268 <li><a href="#int_overflow">Arithmetic with Overflow Intrinsics</a>
269 <ol>
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]270 <li><a href="#int_sadd_overflow">'<tt>llvm.sadd.with.overflow.*</tt> Intrinsics</a></li>
271 <li><a href="#int_uadd_overflow">'<tt>llvm.uadd.with.overflow.*</tt> Intrinsics</a></li>
272 <li><a href="#int_ssub_overflow">'<tt>llvm.ssub.with.overflow.*</tt> Intrinsics</a></li>
273 <li><a href="#int_usub_overflow">'<tt>llvm.usub.with.overflow.*</tt> Intrinsics</a></li>
274 <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]275 <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]276 </ol>
277 </li>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]278 <li><a href="#int_fp16">Half Precision Floating Point Intrinsics</a>
279 <ol>
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]280 <li><a href="#int_convert_to_fp16">'<tt>llvm.convert.to.fp16</tt>' Intrinsic</a></li>
281 <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]282 </ol>
283 </li>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]284 <li><a href="#int_debugger">Debugger intrinsics</a></li>
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]285 <li><a href="#int_eh">Exception Handling intrinsics</a></li>
Duncan Sands4a544a72011-09-06 13:37:06 +0000[diff] [blame]286 <li><a href="#int_trampoline">Trampoline Intrinsics</a>
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]287 <ol>
288 <li><a href="#int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a></li>
Duncan Sands4a544a72011-09-06 13:37:06 +0000[diff] [blame]289 <li><a href="#int_at">'<tt>llvm.adjust.trampoline</tt>' Intrinsic</a></li>
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]290 </ol>
291 </li>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]292 <li><a href="#int_memorymarkers">Memory Use Markers</a>
293 <ol>
Jakub Staszak8e1b12a2011-12-04 20:44:25 +0000[diff] [blame]294 <li><a href="#int_lifetime_start">'<tt>llvm.lifetime.start</tt>' Intrinsic</a></li>
295 <li><a href="#int_lifetime_end">'<tt>llvm.lifetime.end</tt>' Intrinsic</a></li>
296 <li><a href="#int_invariant_start">'<tt>llvm.invariant.start</tt>' Intrinsic</a></li>
297 <li><a href="#int_invariant_end">'<tt>llvm.invariant.end</tt>' Intrinsic</a></li>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]298 </ol>
299 </li>
Reid Spencer20677642007-07-20 19:59:11 +0000[diff] [blame]300 <li><a href="#int_general">General intrinsics</a>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]301 <ol>
Reid Spencer20677642007-07-20 19:59:11 +0000[diff] [blame]302 <li><a href="#int_var_annotation">
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]303 '<tt>llvm.var.annotation</tt>' Intrinsic</a></li>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]304 <li><a href="#int_annotation">
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]305 '<tt>llvm.annotation.*</tt>' Intrinsic</a></li>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]306 <li><a href="#int_trap">
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]307 '<tt>llvm.trap</tt>' Intrinsic</a></li>
308 <li><a href="#int_stackprotector">
309 '<tt>llvm.stackprotector</tt>' Intrinsic</a></li>
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]310 <li><a href="#int_objectsize">
311 '<tt>llvm.objectsize</tt>' Intrinsic</a></li>
Jakub Staszakb170e2d2011-12-04 18:29:26 +0000[diff] [blame]312 <li><a href="#int_expect">
313 '<tt>llvm.expect</tt>' Intrinsic</a></li>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]314 </ol>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]315 </li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]316 </ol>
317 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]318</ol>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]319
320<div class="doc_author">
321 <p>Written by <a href="mailto:sabre@nondot.org">Chris Lattner</a>
322 and <a href="mailto:vadve@cs.uiuc.edu">Vikram Adve</a></p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]323</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]324
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]325<!-- *********************************************************************** -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]326<h2><a name="abstract">Abstract</a></h2>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]327<!-- *********************************************************************** -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]328
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]329<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]330
331<p>This document is a reference manual for the LLVM assembly language. LLVM is
332 a Static Single Assignment (SSA) based representation that provides type
333 safety, low-level operations, flexibility, and the capability of representing
334 'all' high-level languages cleanly. It is the common code representation
335 used throughout all phases of the LLVM compilation strategy.</p>
336
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]337</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]338
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]339<!-- *********************************************************************** -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]340<h2><a name="introduction">Introduction</a></h2>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]341<!-- *********************************************************************** -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]342
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]343<div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]344
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]345<p>The LLVM code representation is designed to be used in three different forms:
346 as an in-memory compiler IR, as an on-disk bitcode representation (suitable
347 for fast loading by a Just-In-Time compiler), and as a human readable
348 assembly language representation. This allows LLVM to provide a powerful
349 intermediate representation for efficient compiler transformations and
350 analysis, while providing a natural means to debug and visualize the
351 transformations. The three different forms of LLVM are all equivalent. This
352 document describes the human readable representation and notation.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]353
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]354<p>The LLVM representation aims to be light-weight and low-level while being
355 expressive, typed, and extensible at the same time. It aims to be a
356 "universal IR" of sorts, by being at a low enough level that high-level ideas
357 may be cleanly mapped to it (similar to how microprocessors are "universal
358 IR's", allowing many source languages to be mapped to them). By providing
359 type information, LLVM can be used as the target of optimizations: for
360 example, through pointer analysis, it can be proven that a C automatic
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]361 variable is never accessed outside of the current function, allowing it to
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]362 be promoted to a simple SSA value instead of a memory location.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]363
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]364<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]365<h4>
366 <a name="wellformed">Well-Formedness</a>
367</h4>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]368
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]369<div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]370
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]371<p>It is important to note that this document describes 'well formed' LLVM
372 assembly language. There is a difference between what the parser accepts and
373 what is considered 'well formed'. For example, the following instruction is
374 syntactically okay, but not well formed:</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]375
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]376<pre class="doc_code">
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]377%x = <a href="#i_add">add</a> i32 1, %x
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]378</pre>
379
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]380<p>because the definition of <tt>%x</tt> does not dominate all of its uses. The
381 LLVM infrastructure provides a verification pass that may be used to verify
382 that an LLVM module is well formed. This pass is automatically run by the
383 parser after parsing input assembly and by the optimizer before it outputs
384 bitcode. The violations pointed out by the verifier pass indicate bugs in
385 transformation passes or input to the parser.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]386
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]387</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]388
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]389</div>
390
Chris Lattnercc689392007-10-03 17:34:29 +0000[diff] [blame]391<!-- Describe the typesetting conventions here. -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]392
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]393<!-- *********************************************************************** -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]394<h2><a name="identifiers">Identifiers</a></h2>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]395<!-- *********************************************************************** -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]396
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]397<div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]398
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]399<p>LLVM identifiers come in two basic types: global and local. Global
400 identifiers (functions, global variables) begin with the <tt>'@'</tt>
401 character. Local identifiers (register names, types) begin with
402 the <tt>'%'</tt> character. Additionally, there are three different formats
403 for identifiers, for different purposes:</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]404
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]405<ol>
Reid Spencer2c452282007-08-07 14:34:28 +0000[diff] [blame]406 <li>Named values are represented as a string of characters with their prefix.
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]407 For example, <tt>%foo</tt>, <tt>@DivisionByZero</tt>,
408 <tt>%a.really.long.identifier</tt>. The actual regular expression used is
409 '<tt>[%@][a-zA-Z$._][a-zA-Z$._0-9]*</tt>'. Identifiers which require
410 other characters in their names can be surrounded with quotes. Special
411 characters may be escaped using <tt>"\xx"</tt> where <tt>xx</tt> is the
412 ASCII code for the character in hexadecimal. In this way, any character
413 can be used in a name value, even quotes themselves.</li>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]414
Reid Spencer2c452282007-08-07 14:34:28 +0000[diff] [blame]415 <li>Unnamed values are represented as an unsigned numeric value with their
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]416 prefix. For example, <tt>%12</tt>, <tt>@2</tt>, <tt>%44</tt>.</li>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]417
Reid Spencercc16dc32004-12-09 18:02:53 +0000[diff] [blame]418 <li>Constants, which are described in a <a href="#constants">section about
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]419 constants</a>, below.</li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]420</ol>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]421
Reid Spencer2c452282007-08-07 14:34:28 +0000[diff] [blame]422<p>LLVM requires that values start with a prefix for two reasons: Compilers
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]423 don't need to worry about name clashes with reserved words, and the set of
424 reserved words may be expanded in the future without penalty. Additionally,
425 unnamed identifiers allow a compiler to quickly come up with a temporary
426 variable without having to avoid symbol table conflicts.</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]427
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]428<p>Reserved words in LLVM are very similar to reserved words in other
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]429 languages. There are keywords for different opcodes
430 ('<tt><a href="#i_add">add</a></tt>',
431 '<tt><a href="#i_bitcast">bitcast</a></tt>',
432 '<tt><a href="#i_ret">ret</a></tt>', etc...), for primitive type names
433 ('<tt><a href="#t_void">void</a></tt>',
434 '<tt><a href="#t_primitive">i32</a></tt>', etc...), and others. These
435 reserved words cannot conflict with variable names, because none of them
436 start with a prefix character (<tt>'%'</tt> or <tt>'@'</tt>).</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]437
438<p>Here is an example of LLVM code to multiply the integer variable
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]439 '<tt>%X</tt>' by 8:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]440
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]441<p>The easy way:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]442
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]443<pre class="doc_code">
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]444%result = <a href="#i_mul">mul</a> i32 %X, 8
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]445</pre>
446
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]447<p>After strength reduction:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]448
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]449<pre class="doc_code">
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]450%result = <a href="#i_shl">shl</a> i32 %X, i8 3
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]451</pre>
452
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]453<p>And the hard way:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]454
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]455<pre class="doc_code">
Gabor Greifec58f752009-10-28 13:05:07 +0000[diff] [blame]456%0 = <a href="#i_add">add</a> i32 %X, %X <i>; yields {i32}:%0</i>
457%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]458%result = <a href="#i_add">add</a> i32 %1, %1
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]459</pre>
460
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]461<p>This last way of multiplying <tt>%X</tt> by 8 illustrates several important
462 lexical features of LLVM:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]463
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]464<ol>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]465 <li>Comments are delimited with a '<tt>;</tt>' and go until the end of
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]466 line.</li>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]467
468 <li>Unnamed temporaries are created when the result of a computation is not
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]469 assigned to a named value.</li>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]470
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]471 <li>Unnamed temporaries are numbered sequentially</li>
472</ol>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]473
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]474<p>It also shows a convention that we follow in this document. When
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]475 demonstrating instructions, we will follow an instruction with a comment that
476 defines the type and name of value produced. Comments are shown in italic
477 text.</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]478
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]479</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]480
481<!-- *********************************************************************** -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]482<h2><a name="highlevel">High Level Structure</a></h2>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]483<!-- *********************************************************************** -->
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]484<div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]485<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]486<h3>
487 <a name="modulestructure">Module Structure</a>
488</h3>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]489
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]490<div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]491
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]492<p>LLVM programs are composed of "Module"s, each of which is a translation unit
493 of the input programs. Each module consists of functions, global variables,
494 and symbol table entries. Modules may be combined together with the LLVM
495 linker, which merges function (and global variable) definitions, resolves
496 forward declarations, and merges symbol table entries. Here is an example of
497 the "hello world" module:</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]498
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]499<pre class="doc_code">
Chris Lattner63e4ccb2010-08-17 17:13:42 +0000[diff] [blame]500<i>; Declare the string constant as a global constant.</i>&nbsp;
Nick Lewyckydb9cd762011-01-29 01:09:53 +0000[diff] [blame]501<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]502
Chris Lattner63e4ccb2010-08-17 17:13:42 +0000[diff] [blame]503<i>; External declaration of the puts function</i>&nbsp;
504<a href="#functionstructure">declare</a> i32 @puts(i8*) <i>; i32 (i8*)* </i>&nbsp;
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]505
506<i>; Definition of main function</i>
Chris Lattner63e4ccb2010-08-17 17:13:42 +0000[diff] [blame]507define i32 @main() { <i>; i32()* </i>&nbsp;
508 <i>; Convert [13 x i8]* to i8 *...</i>&nbsp;
509 %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]510
Chris Lattner63e4ccb2010-08-17 17:13:42 +0000[diff] [blame]511 <i>; Call puts function to write out the string to stdout.</i>&nbsp;
512 <a href="#i_call">call</a> i32 @puts(i8* %cast210) <i>; i32</i>&nbsp;
513 <a href="#i_ret">ret</a> i32 0&nbsp;
514}
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]515
516<i>; Named metadata</i>
517!1 = metadata !{i32 41}
518!foo = !{!1, null}
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]519</pre>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]520
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]521<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]522 "<tt>.LC0</tt>", an external declaration of the "<tt>puts</tt>" function,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]523 a <a href="#functionstructure">function definition</a> for
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]524 "<tt>main</tt>" and <a href="#namedmetadatastructure">named metadata</a>
525 "<tt>foo"</tt>.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]526
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]527<p>In general, a module is made up of a list of global values, where both
528 functions and global variables are global values. Global values are
529 represented by a pointer to a memory location (in this case, a pointer to an
530 array of char, and a pointer to a function), and have one of the
531 following <a href="#linkage">linkage types</a>.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]532
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]533</div>
534
535<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]536<h3>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]537 <a name="linkage">Linkage Types</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]538</h3>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]539
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]540<div>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]541
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]542<p>All Global Variables and Functions have one of the following types of
543 linkage:</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]544
545<dl>
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]546 <dt><tt><b><a name="linkage_private">private</a></b></tt></dt>
Bill Wendling5e721d72010-07-01 21:55:59 +0000[diff] [blame]547 <dd>Global values with "<tt>private</tt>" linkage are only directly accessible
548 by objects in the current module. In particular, linking code into a
549 module with an private global value may cause the private to be renamed as
550 necessary to avoid collisions. Because the symbol is private to the
551 module, all references can be updated. This doesn't show up in any symbol
552 table in the object file.</dd>
Rafael Espindolabb46f522009-01-15 20:18:42 +0000[diff] [blame]553
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]554 <dt><tt><b><a name="linkage_linker_private">linker_private</a></b></tt></dt>
Bill Wendling5e721d72010-07-01 21:55:59 +0000[diff] [blame]555 <dd>Similar to <tt>private</tt>, but the symbol is passed through the
556 assembler and evaluated by the linker. Unlike normal strong symbols, they
557 are removed by the linker from the final linked image (executable or
558 dynamic library).</dd>
559
560 <dt><tt><b><a name="linkage_linker_private_weak">linker_private_weak</a></b></tt></dt>
561 <dd>Similar to "<tt>linker_private</tt>", but the symbol is weak. Note that
562 <tt>linker_private_weak</tt> symbols are subject to coalescing by the
563 linker. The symbols are removed by the linker from the final linked image
564 (executable or dynamic library).</dd>
Bill Wendling3d10a5a2009-07-20 01:03:30 +0000[diff] [blame]565
Bill Wendling55ae5152010-08-20 22:05:50 +0000[diff] [blame]566 <dt><tt><b><a name="linkage_linker_private_weak_def_auto">linker_private_weak_def_auto</a></b></tt></dt>
567 <dd>Similar to "<tt>linker_private_weak</tt>", but it's known that the address
568 of the object is not taken. For instance, functions that had an inline
569 definition, but the compiler decided not to inline it. Note,
570 unlike <tt>linker_private</tt> and <tt>linker_private_weak</tt>,
571 <tt>linker_private_weak_def_auto</tt> may have only <tt>default</tt>
572 visibility. The symbols are removed by the linker from the final linked
573 image (executable or dynamic library).</dd>
574
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]575 <dt><tt><b><a name="linkage_internal">internal</a></b></tt></dt>
Bill Wendling07d31772010-06-29 22:34:52 +0000[diff] [blame]576 <dd>Similar to private, but the value shows as a local symbol
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]577 (<tt>STB_LOCAL</tt> in the case of ELF) in the object file. This
578 corresponds to the notion of the '<tt>static</tt>' keyword in C.</dd>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]579
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]580 <dt><tt><b><a name="linkage_available_externally">available_externally</a></b></tt></dt>
Chris Lattner266c7bb2009-04-13 05:44:34 +0000[diff] [blame]581 <dd>Globals with "<tt>available_externally</tt>" linkage are never emitted
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]582 into the object file corresponding to the LLVM module. They exist to
583 allow inlining and other optimizations to take place given knowledge of
584 the definition of the global, which is known to be somewhere outside the
585 module. Globals with <tt>available_externally</tt> linkage are allowed to
586 be discarded at will, and are otherwise the same as <tt>linkonce_odr</tt>.
587 This linkage type is only allowed on definitions, not declarations.</dd>
Chris Lattner266c7bb2009-04-13 05:44:34 +0000[diff] [blame]588
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]589 <dt><tt><b><a name="linkage_linkonce">linkonce</a></b></tt></dt>
Chris Lattner4887bd82007-01-14 06:51:48 +0000[diff] [blame]590 <dd>Globals with "<tt>linkonce</tt>" linkage are merged with other globals of
Chris Lattner873187c2010-01-09 19:15:14 +0000[diff] [blame]591 the same name when linkage occurs. This can be used to implement
592 some forms of inline functions, templates, or other code which must be
593 generated in each translation unit that uses it, but where the body may
594 be overridden with a more definitive definition later. Unreferenced
595 <tt>linkonce</tt> globals are allowed to be discarded. Note that
596 <tt>linkonce</tt> linkage does not actually allow the optimizer to
597 inline the body of this function into callers because it doesn't know if
598 this definition of the function is the definitive definition within the
599 program or whether it will be overridden by a stronger definition.
600 To enable inlining and other optimizations, use "<tt>linkonce_odr</tt>"
601 linkage.</dd>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]602
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]603 <dt><tt><b><a name="linkage_weak">weak</a></b></tt></dt>
Chris Lattner26d054d2009-08-05 05:21:07 +0000[diff] [blame]604 <dd>"<tt>weak</tt>" linkage has the same merging semantics as
605 <tt>linkonce</tt> linkage, except that unreferenced globals with
606 <tt>weak</tt> linkage may not be discarded. This is used for globals that
607 are declared "weak" in C source code.</dd>
608
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]609 <dt><tt><b><a name="linkage_common">common</a></b></tt></dt>
Chris Lattner26d054d2009-08-05 05:21:07 +0000[diff] [blame]610 <dd>"<tt>common</tt>" linkage is most similar to "<tt>weak</tt>" linkage, but
611 they are used for tentative definitions in C, such as "<tt>int X;</tt>" at
612 global scope.
613 Symbols with "<tt>common</tt>" linkage are merged in the same way as
614 <tt>weak symbols</tt>, and they may not be deleted if unreferenced.
Chris Lattnercd81f5d2009-08-05 05:41:44 +0000[diff] [blame]615 <tt>common</tt> symbols may not have an explicit section,
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]616 must have a zero initializer, and may not be marked '<a
Chris Lattnercd81f5d2009-08-05 05:41:44 +0000[diff] [blame]617 href="#globalvars"><tt>constant</tt></a>'. Functions and aliases may not
618 have common linkage.</dd>
Chris Lattner26d054d2009-08-05 05:21:07 +0000[diff] [blame]619
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]620
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]621 <dt><tt><b><a name="linkage_appending">appending</a></b></tt></dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]622 <dd>"<tt>appending</tt>" linkage may only be applied to global variables of
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]623 pointer to array type. When two global variables with appending linkage
624 are linked together, the two global arrays are appended together. This is
625 the LLVM, typesafe, equivalent of having the system linker append together
626 "sections" with identical names when .o files are linked.</dd>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]627
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]628 <dt><tt><b><a name="linkage_externweak">extern_weak</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]629 <dd>The semantics of this linkage follow the ELF object file model: the symbol
630 is weak until linked, if not linked, the symbol becomes null instead of
631 being an undefined reference.</dd>
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]632
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]633 <dt><tt><b><a name="linkage_linkonce_odr">linkonce_odr</a></b></tt></dt>
634 <dt><tt><b><a name="linkage_weak_odr">weak_odr</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]635 <dd>Some languages allow differing globals to be merged, such as two functions
636 with different semantics. Other languages, such as <tt>C++</tt>, ensure
Bill Wendling5e721d72010-07-01 21:55:59 +0000[diff] [blame]637 that only equivalent globals are ever merged (the "one definition rule"
638 &mdash; "ODR"). Such languages can use the <tt>linkonce_odr</tt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]639 and <tt>weak_odr</tt> linkage types to indicate that the global will only
640 be merged with equivalent globals. These linkage types are otherwise the
641 same as their non-<tt>odr</tt> versions.</dd>
Duncan Sands667d4b82009-03-07 15:45:40 +0000[diff] [blame]642
Bill Wendling5c3a9f72011-11-04 20:40:41 +0000[diff] [blame]643 <dt><tt><b><a name="linkage_external">external</a></b></tt></dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]644 <dd>If none of the above identifiers are used, the global is externally
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]645 visible, meaning that it participates in linkage and can be used to
646 resolve external symbol references.</dd>
Reid Spencerc8910842007-04-11 23:49:50 +0000[diff] [blame]647</dl>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]648
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]649<p>The next two types of linkage are targeted for Microsoft Windows platform
650 only. They are designed to support importing (exporting) symbols from (to)
651 DLLs (Dynamic Link Libraries).</p>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]652
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]653<dl>
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]654 <dt><tt><b><a name="linkage_dllimport">dllimport</a></b></tt></dt>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]655 <dd>"<tt>dllimport</tt>" linkage causes the compiler to reference a function
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]656 or variable via a global pointer to a pointer that is set up by the DLL
657 exporting the symbol. On Microsoft Windows targets, the pointer name is
658 formed by combining <code>__imp_</code> and the function or variable
659 name.</dd>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]660
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]661 <dt><tt><b><a name="linkage_dllexport">dllexport</a></b></tt></dt>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]662 <dd>"<tt>dllexport</tt>" linkage causes the compiler to provide a global
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]663 pointer to a pointer in a DLL, so that it can be referenced with the
664 <tt>dllimport</tt> attribute. On Microsoft Windows targets, the pointer
665 name is formed by combining <code>__imp_</code> and the function or
666 variable name.</dd>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]667</dl>
668
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]669<p>For example, since the "<tt>.LC0</tt>" variable is defined to be internal, if
670 another module defined a "<tt>.LC0</tt>" variable and was linked with this
671 one, one of the two would be renamed, preventing a collision. Since
672 "<tt>main</tt>" and "<tt>puts</tt>" are external (i.e., lacking any linkage
673 declarations), they are accessible outside of the current module.</p>
674
675<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]676 other than <tt>external</tt>, <tt>dllimport</tt>
677 or <tt>extern_weak</tt>.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]678
Duncan Sands667d4b82009-03-07 15:45:40 +0000[diff] [blame]679<p>Aliases can have only <tt>external</tt>, <tt>internal</tt>, <tt>weak</tt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]680 or <tt>weak_odr</tt> linkages.</p>
681
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]682</div>
683
684<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]685<h3>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]686 <a name="callingconv">Calling Conventions</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]687</h3>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]688
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]689<div>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]690
691<p>LLVM <a href="#functionstructure">functions</a>, <a href="#i_call">calls</a>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]692 and <a href="#i_invoke">invokes</a> can all have an optional calling
693 convention specified for the call. The calling convention of any pair of
694 dynamic caller/callee must match, or the behavior of the program is
695 undefined. The following calling conventions are supported by LLVM, and more
696 may be added in the future:</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]697
698<dl>
699 <dt><b>"<tt>ccc</tt>" - The C calling convention</b>:</dt>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]700 <dd>This calling convention (the default if no other calling convention is
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]701 specified) matches the target C calling conventions. This calling
702 convention supports varargs function calls and tolerates some mismatch in
703 the declared prototype and implemented declaration of the function (as
704 does normal C).</dd>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]705
706 <dt><b>"<tt>fastcc</tt>" - The fast calling convention</b>:</dt>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]707 <dd>This calling convention attempts to make calls as fast as possible
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]708 (e.g. by passing things in registers). This calling convention allows the
709 target to use whatever tricks it wants to produce fast code for the
710 target, without having to conform to an externally specified ABI
Jeffrey Yasskin95fa80a2010-01-09 19:44:16 +0000[diff] [blame]711 (Application Binary Interface).
712 <a href="CodeGenerator.html#tailcallopt">Tail calls can only be optimized
Chris Lattner29689432010-03-11 00:22:57 +0000[diff] [blame]713 when this or the GHC convention is used.</a> This calling convention
714 does not support varargs and requires the prototype of all callees to
715 exactly match the prototype of the function definition.</dd>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]716
717 <dt><b>"<tt>coldcc</tt>" - The cold calling convention</b>:</dt>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]718 <dd>This calling convention attempts to make code in the caller as efficient
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]719 as possible under the assumption that the call is not commonly executed.
720 As such, these calls often preserve all registers so that the call does
721 not break any live ranges in the caller side. This calling convention
722 does not support varargs and requires the prototype of all callees to
723 exactly match the prototype of the function definition.</dd>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]724
Chris Lattner29689432010-03-11 00:22:57 +0000[diff] [blame]725 <dt><b>"<tt>cc <em>10</em></tt>" - GHC convention</b>:</dt>
726 <dd>This calling convention has been implemented specifically for use by the
727 <a href="http://www.haskell.org/ghc">Glasgow Haskell Compiler (GHC)</a>.
728 It passes everything in registers, going to extremes to achieve this by
729 disabling callee save registers. This calling convention should not be
730 used lightly but only for specific situations such as an alternative to
731 the <em>register pinning</em> performance technique often used when
732 implementing functional programming languages.At the moment only X86
733 supports this convention and it has the following limitations:
734 <ul>
735 <li>On <em>X86-32</em> only supports up to 4 bit type parameters. No
736 floating point types are supported.</li>
737 <li>On <em>X86-64</em> only supports up to 10 bit type parameters and
738 6 floating point parameters.</li>
739 </ul>
740 This calling convention supports
741 <a href="CodeGenerator.html#tailcallopt">tail call optimization</a> but
742 requires both the caller and callee are using it.
743 </dd>
744
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame]745 <dt><b>"<tt>cc &lt;<em>n</em>&gt;</tt>" - Numbered convention</b>:</dt>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]746 <dd>Any calling convention may be specified by number, allowing
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]747 target-specific calling conventions to be used. Target specific calling
748 conventions start at 64.</dd>
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame]749</dl>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]750
751<p>More calling conventions can be added/defined on an as-needed basis, to
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]752 support Pascal conventions or any other well-known target-independent
753 convention.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]754
755</div>
756
757<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]758<h3>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]759 <a name="visibility">Visibility Styles</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]760</h3>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]761
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]762<div>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]763
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]764<p>All Global Variables and Functions have one of the following visibility
765 styles:</p>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]766
767<dl>
768 <dt><b>"<tt>default</tt>" - Default style</b>:</dt>
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]769 <dd>On targets that use the ELF object file format, default visibility means
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]770 that the declaration is visible to other modules and, in shared libraries,
771 means that the declared entity may be overridden. On Darwin, default
772 visibility means that the declaration is visible to other modules. Default
773 visibility corresponds to "external linkage" in the language.</dd>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]774
775 <dt><b>"<tt>hidden</tt>" - Hidden style</b>:</dt>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]776 <dd>Two declarations of an object with hidden visibility refer to the same
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]777 object if they are in the same shared object. Usually, hidden visibility
778 indicates that the symbol will not be placed into the dynamic symbol
779 table, so no other module (executable or shared library) can reference it
780 directly.</dd>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]781
Anton Korobeynikov6f9896f2007-04-29 18:35:00 +0000[diff] [blame]782 <dt><b>"<tt>protected</tt>" - Protected style</b>:</dt>
Anton Korobeynikov6f9896f2007-04-29 18:35:00 +0000[diff] [blame]783 <dd>On ELF, protected visibility indicates that the symbol will be placed in
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]784 the dynamic symbol table, but that references within the defining module
785 will bind to the local symbol. That is, the symbol cannot be overridden by
786 another module.</dd>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]787</dl>
788
789</div>
790
791<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]792<h3>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]793 <a name="namedtypes">Named Types</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]794</h3>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]795
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]796<div>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]797
798<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]799 it easier to read the IR and make the IR more condensed (particularly when
800 recursive types are involved). An example of a name specification is:</p>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]801
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]802<pre class="doc_code">
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]803%mytype = type { %mytype*, i32 }
804</pre>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]805
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]806<p>You may give a name to any <a href="#typesystem">type</a> except
Chris Lattnerdc65f222010-08-17 23:26:04 +0000[diff] [blame]807 "<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]808 is expected with the syntax "%mytype".</p>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]809
810<p>Note that type names are aliases for the structural type that they indicate,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]811 and that you can therefore specify multiple names for the same type. This
812 often leads to confusing behavior when dumping out a .ll file. Since LLVM IR
813 uses structural typing, the name is not part of the type. When printing out
814 LLVM IR, the printer will pick <em>one name</em> to render all types of a
815 particular shape. This means that if you have code where two different
816 source types end up having the same LLVM type, that the dumper will sometimes
817 print the "wrong" or unexpected type. This is an important design point and
818 isn't going to change.</p>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]819
820</div>
821
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]822<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]823<h3>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]824 <a name="globalvars">Global Variables</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]825</h3>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]826
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]827<div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]828
Chris Lattner3689a342005-02-12 19:30:21 +0000[diff] [blame]829<p>Global variables define regions of memory allocated at compilation time
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]830 instead of run-time. Global variables may optionally be initialized, may
831 have an explicit section to be placed in, and may have an optional explicit
832 alignment specified. A variable may be defined as "thread_local", which
833 means that it will not be shared by threads (each thread will have a
834 separated copy of the variable). A variable may be defined as a global
835 "constant," which indicates that the contents of the variable
836 will <b>never</b> be modified (enabling better optimization, allowing the
837 global data to be placed in the read-only section of an executable, etc).
838 Note that variables that need runtime initialization cannot be marked
839 "constant" as there is a store to the variable.</p>
Chris Lattner3689a342005-02-12 19:30:21 +0000[diff] [blame]840
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]841<p>LLVM explicitly allows <em>declarations</em> of global variables to be marked
842 constant, even if the final definition of the global is not. This capability
843 can be used to enable slightly better optimization of the program, but
844 requires the language definition to guarantee that optimizations based on the
845 'constantness' are valid for the translation units that do not include the
846 definition.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]847
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]848<p>As SSA values, global variables define pointer values that are in scope
849 (i.e. they dominate) all basic blocks in the program. Global variables
850 always define a pointer to their "content" type because they describe a
851 region of memory, and all memory objects in LLVM are accessed through
852 pointers.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]853
Rafael Espindolabea46262011-01-08 16:42:36 +0000[diff] [blame]854<p>Global variables can be marked with <tt>unnamed_addr</tt> which indicates
855 that the address is not significant, only the content. Constants marked
Rafael Espindolaa5eaa862011-01-15 08:20:57 +0000[diff] [blame]856 like this can be merged with other constants if they have the same
857 initializer. Note that a constant with significant address <em>can</em>
858 be merged with a <tt>unnamed_addr</tt> constant, the result being a
859 constant whose address is significant.</p>
Rafael Espindolabea46262011-01-08 16:42:36 +0000[diff] [blame]860
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]861<p>A global variable may be declared to reside in a target-specific numbered
862 address space. For targets that support them, address spaces may affect how
863 optimizations are performed and/or what target instructions are used to
864 access the variable. The default address space is zero. The address space
865 qualifier must precede any other attributes.</p>
Christopher Lamb284d9922007-12-11 09:31:00 +0000[diff] [blame]866
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]867<p>LLVM allows an explicit section to be specified for globals. If the target
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]868 supports it, it will emit globals to the section specified.</p>
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]869
Chris Lattnerce99fa92010-04-28 00:13:42 +0000[diff] [blame]870<p>An explicit alignment may be specified for a global, which must be a power
871 of 2. If not present, or if the alignment is set to zero, the alignment of
872 the global is set by the target to whatever it feels convenient. If an
873 explicit alignment is specified, the global is forced to have exactly that
Chris Lattner2d4b8ee2010-04-28 00:31:12 +0000[diff] [blame]874 alignment. Targets and optimizers are not allowed to over-align the global
875 if the global has an assigned section. In this case, the extra alignment
876 could be observable: for example, code could assume that the globals are
877 densely packed in their section and try to iterate over them as an array,
878 alignment padding would break this iteration.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]879
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]880<p>For example, the following defines a global in a numbered address space with
881 an initializer, section, and alignment:</p>
Chris Lattner68027ea2007-01-14 00:27:09 +0000[diff] [blame]882
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]883<pre class="doc_code">
Dan Gohman398873c2009-01-11 00:40:00 +0000[diff] [blame]884@G = addrspace(5) constant float 1.0, section "foo", align 4
Chris Lattner68027ea2007-01-14 00:27:09 +0000[diff] [blame]885</pre>
886
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]887</div>
888
889
890<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]891<h3>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]892 <a name="functionstructure">Functions</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]893</h3>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]894
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]895<div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]896
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]897<p>LLVM function definitions consist of the "<tt>define</tt>" keyword, an
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]898 optional <a href="#linkage">linkage type</a>, an optional
899 <a href="#visibility">visibility style</a>, an optional
Rafael Espindolabea46262011-01-08 16:42:36 +0000[diff] [blame]900 <a href="#callingconv">calling convention</a>,
901 an optional <tt>unnamed_addr</tt> attribute, a return type, an optional
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]902 <a href="#paramattrs">parameter attribute</a> for the return type, a function
903 name, a (possibly empty) argument list (each with optional
904 <a href="#paramattrs">parameter attributes</a>), optional
905 <a href="#fnattrs">function attributes</a>, an optional section, an optional
906 alignment, an optional <a href="#gc">garbage collector name</a>, an opening
907 curly brace, a list of basic blocks, and a closing curly brace.</p>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]908
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]909<p>LLVM function declarations consist of the "<tt>declare</tt>" keyword, an
910 optional <a href="#linkage">linkage type</a>, an optional
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]911 <a href="#visibility">visibility style</a>, an optional
Rafael Espindolabea46262011-01-08 16:42:36 +0000[diff] [blame]912 <a href="#callingconv">calling convention</a>,
913 an optional <tt>unnamed_addr</tt> attribute, a return type, an optional
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]914 <a href="#paramattrs">parameter attribute</a> for the return type, a function
915 name, a possibly empty list of arguments, an optional alignment, and an
916 optional <a href="#gc">garbage collector name</a>.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]917
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]918<p>A function definition contains a list of basic blocks, forming the CFG
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]919 (Control Flow Graph) for the function. Each basic block may optionally start
920 with a label (giving the basic block a symbol table entry), contains a list
921 of instructions, and ends with a <a href="#terminators">terminator</a>
922 instruction (such as a branch or function return).</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]923
Chris Lattner4a3c9012007-06-08 16:52:14 +0000[diff] [blame]924<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]925 executed on entrance to the function, and it is not allowed to have
926 predecessor basic blocks (i.e. there can not be any branches to the entry
927 block of a function). Because the block can have no predecessors, it also
928 cannot have any <a href="#i_phi">PHI nodes</a>.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]929
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]930<p>LLVM allows an explicit section to be specified for functions. If the target
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]931 supports it, it will emit functions to the section specified.</p>
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]932
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]933<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]934 the alignment is set to zero, the alignment of the function is set by the
935 target to whatever it feels convenient. If an explicit alignment is
936 specified, the function is forced to have at least that much alignment. All
937 alignments must be a power of 2.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]938
Rafael Espindolabea46262011-01-08 16:42:36 +0000[diff] [blame]939<p>If the <tt>unnamed_addr</tt> attribute is given, the address is know to not
Bill Wendling5c3a9f72011-11-04 20:40:41 +0000[diff] [blame]940 be significant and two identical functions can be merged.</p>
Rafael Espindolabea46262011-01-08 16:42:36 +0000[diff] [blame]941
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]942<h5>Syntax:</h5>
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]943<pre class="doc_code">
Chris Lattner50ad45c2008-10-13 16:55:18 +0000[diff] [blame]944define [<a href="#linkage">linkage</a>] [<a href="#visibility">visibility</a>]
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]945 [<a href="#callingconv">cconv</a>] [<a href="#paramattrs">ret attrs</a>]
946 &lt;ResultType&gt; @&lt;FunctionName&gt; ([argument list])
947 [<a href="#fnattrs">fn Attrs</a>] [section "name"] [align N]
948 [<a href="#gc">gc</a>] { ... }
949</pre>
Devang Patel307e8ab2008-10-07 17:48:33 +0000[diff] [blame]950
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]951</div>
952
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]953<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]954<h3>
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]955 <a name="aliasstructure">Aliases</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]956</h3>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]957
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]958<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]959
960<p>Aliases act as "second name" for the aliasee value (which can be either
961 function, global variable, another alias or bitcast of global value). Aliases
962 may have an optional <a href="#linkage">linkage type</a>, and an
963 optional <a href="#visibility">visibility style</a>.</p>
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]964
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]965<h5>Syntax:</h5>
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]966<pre class="doc_code">
Duncan Sands0b23ac12008-09-12 20:48:21 +0000[diff] [blame]967@&lt;Name&gt; = alias [Linkage] [Visibility] &lt;AliaseeTy&gt; @&lt;Aliasee&gt;
Bill Wendlingaac388b2007-05-29 09:42:13 +0000[diff] [blame]968</pre>
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]969
970</div>
971
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]972<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]973<h3>
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]974 <a name="namedmetadatastructure">Named Metadata</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]975</h3>
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]976
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]977<div>
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]978
Chris Lattnere6a5ddd2010-01-15 21:50:19 +0000[diff] [blame]979<p>Named metadata is a collection of metadata. <a href="#metadata">Metadata
Dan Gohman872814a2010-07-21 18:54:18 +0000[diff] [blame]980 nodes</a> (but not metadata strings) are the only valid operands for
Chris Lattnere6a5ddd2010-01-15 21:50:19 +0000[diff] [blame]981 a named metadata.</p>
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]982
983<h5>Syntax:</h5>
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]984<pre class="doc_code">
Dan Gohman872814a2010-07-21 18:54:18 +0000[diff] [blame]985; Some unnamed metadata nodes, which are referenced by the named metadata.
986!0 = metadata !{metadata !"zero"}
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]987!1 = metadata !{metadata !"one"}
Dan Gohman872814a2010-07-21 18:54:18 +0000[diff] [blame]988!2 = metadata !{metadata !"two"}
Dan Gohman1005bc52010-07-13 19:48:13 +0000[diff] [blame]989; A named metadata.
Dan Gohman872814a2010-07-21 18:54:18 +0000[diff] [blame]990!name = !{!0, !1, !2}
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]991</pre>
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]992
993</div>
994
995<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]996<h3>
997 <a name="paramattrs">Parameter Attributes</a>
998</h3>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]999
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1000<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1001
1002<p>The return type and each parameter of a function type may have a set of
1003 <i>parameter attributes</i> associated with them. Parameter attributes are
1004 used to communicate additional information about the result or parameters of
1005 a function. Parameter attributes are considered to be part of the function,
1006 not of the function type, so functions with different parameter attributes
1007 can have the same function type.</p>
1008
1009<p>Parameter attributes are simple keywords that follow the type specified. If
1010 multiple parameter attributes are needed, they are space separated. For
1011 example:</p>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1012
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]1013<pre class="doc_code">
Nick Lewyckyb6a7d252009-02-15 23:06:14 +0000[diff] [blame]1014declare i32 @printf(i8* noalias nocapture, ...)
Chris Lattner66d922c2008-10-04 18:33:34 +0000[diff] [blame]1015declare i32 @atoi(i8 zeroext)
1016declare signext i8 @returns_signed_char()
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1017</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1018
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1019<p>Note that any attributes for the function result (<tt>nounwind</tt>,
1020 <tt>readonly</tt>) come immediately after the argument list.</p>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1021
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1022<p>Currently, only the following parameter attributes are defined:</p>
Chris Lattner47507de2008-01-11 06:20:47 +0000[diff] [blame]1023
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1024<dl>
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1025 <dt><tt><b>zeroext</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1026 <dd>This indicates to the code generator that the parameter or return value
Cameron Zwarichebe81732011-03-16 22:20:18 +0000[diff] [blame]1027 should be zero-extended to the extent required by the target's ABI (which
1028 is usually 32-bits, but is 8-bits for a i1 on x86-64) by the caller (for a
1029 parameter) or the callee (for a return value).</dd>
Chris Lattner47507de2008-01-11 06:20:47 +0000[diff] [blame]1030
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1031 <dt><tt><b>signext</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1032 <dd>This indicates to the code generator that the parameter or return value
Cameron Zwarich9e69ff92011-03-17 14:21:58 +0000[diff] [blame]1033 should be sign-extended to the extent required by the target's ABI (which
1034 is usually 32-bits) by the caller (for a parameter) or the callee (for a
1035 return value).</dd>
Chris Lattner47507de2008-01-11 06:20:47 +0000[diff] [blame]1036
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1037 <dt><tt><b>inreg</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1038 <dd>This indicates that this parameter or return value should be treated in a
1039 special target-dependent fashion during while emitting code for a function
1040 call or return (usually, by putting it in a register as opposed to memory,
1041 though some targets use it to distinguish between two different kinds of
1042 registers). Use of this attribute is target-specific.</dd>
Chris Lattner47507de2008-01-11 06:20:47 +0000[diff] [blame]1043
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1044 <dt><tt><b><a name="byval">byval</a></b></tt></dt>
Chris Lattnera6fd81d2010-11-20 23:49:06 +0000[diff] [blame]1045 <dd><p>This indicates that the pointer parameter should really be passed by
1046 value to the function. The attribute implies that a hidden copy of the
1047 pointee
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1048 is made between the caller and the callee, so the callee is unable to
1049 modify the value in the callee. This attribute is only valid on LLVM
1050 pointer arguments. It is generally used to pass structs and arrays by
1051 value, but is also valid on pointers to scalars. The copy is considered
1052 to belong to the caller not the callee (for example,
1053 <tt><a href="#readonly">readonly</a></tt> functions should not write to
1054 <tt>byval</tt> parameters). This is not a valid attribute for return
Chris Lattnera6fd81d2010-11-20 23:49:06 +0000[diff] [blame]1055 values.</p>
1056
1057 <p>The byval attribute also supports specifying an alignment with
1058 the align attribute. It indicates the alignment of the stack slot to
1059 form and the known alignment of the pointer specified to the call site. If
1060 the alignment is not specified, then the code generator makes a
1061 target-specific assumption.</p></dd>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1062
Dan Gohmanff235352010-07-02 23:18:08 +0000[diff] [blame]1063 <dt><tt><b><a name="sret">sret</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1064 <dd>This indicates that the pointer parameter specifies the address of a
1065 structure that is the return value of the function in the source program.
1066 This pointer must be guaranteed by the caller to be valid: loads and
1067 stores to the structure may be assumed by the callee to not to trap. This
1068 may only be applied to the first parameter. This is not a valid attribute
1069 for return values. </dd>
1070
Dan Gohmanff235352010-07-02 23:18:08 +0000[diff] [blame]1071 <dt><tt><b><a name="noalias">noalias</a></b></tt></dt>
Dan Gohman1e109622010-07-02 18:41:32 +0000[diff] [blame]1072 <dd>This indicates that pointer values
1073 <a href="#pointeraliasing"><i>based</i></a> on the argument or return
Dan Gohmanefca7f92010-07-02 23:46:54 +0000[diff] [blame]1074 value do not alias pointer values which are not <i>based</i> on it,
1075 ignoring certain "irrelevant" dependencies.
1076 For a call to the parent function, dependencies between memory
1077 references from before or after the call and from those during the call
1078 are "irrelevant" to the <tt>noalias</tt> keyword for the arguments and
1079 return value used in that call.
Dan Gohman1e109622010-07-02 18:41:32 +0000[diff] [blame]1080 The caller shares the responsibility with the callee for ensuring that
1081 these requirements are met.
1082 For further details, please see the discussion of the NoAlias response in
Dan Gohmanff70fe42010-07-06 15:26:33 +0000[diff] [blame]1083 <a href="AliasAnalysis.html#MustMayNo">alias analysis</a>.<br>
1084<br>
John McCall191d4ee2010-07-06 21:07:14 +0000[diff] [blame]1085 Note that this definition of <tt>noalias</tt> is intentionally
1086 similar to the definition of <tt>restrict</tt> in C99 for function
Chris Lattner211244a2010-07-06 20:51:35 +0000[diff] [blame]1087 arguments, though it is slightly weaker.
Dan Gohmanff70fe42010-07-06 15:26:33 +0000[diff] [blame]1088<br>
1089 For function return values, C99's <tt>restrict</tt> is not meaningful,
1090 while LLVM's <tt>noalias</tt> is.
1091 </dd>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1092
Dan Gohmanff235352010-07-02 23:18:08 +0000[diff] [blame]1093 <dt><tt><b><a name="nocapture">nocapture</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1094 <dd>This indicates that the callee does not make any copies of the pointer
1095 that outlive the callee itself. This is not a valid attribute for return
1096 values.</dd>
1097
Dan Gohmanff235352010-07-02 23:18:08 +0000[diff] [blame]1098 <dt><tt><b><a name="nest">nest</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1099 <dd>This indicates that the pointer parameter can be excised using the
1100 <a href="#int_trampoline">trampoline intrinsics</a>. This is not a valid
1101 attribute for return values.</dd>
1102</dl>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1103
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1104</div>
1105
1106<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1107<h3>
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]1108 <a name="gc">Garbage Collector Names</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1109</h3>
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]1110
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1111<div>
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]1112
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1113<p>Each function may specify a garbage collector name, which is simply a
1114 string:</p>
1115
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]1116<pre class="doc_code">
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1117define void @f() gc "name" { ... }
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1118</pre>
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]1119
1120<p>The compiler declares the supported values of <i>name</i>. Specifying a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1121 collector which will cause the compiler to alter its output in order to
1122 support the named garbage collection algorithm.</p>
1123
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]1124</div>
1125
1126<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1127<h3>
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1128 <a name="fnattrs">Function Attributes</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1129</h3>
Devang Patelf8b94812008-09-04 23:05:13 +0000[diff] [blame]1130
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1131<div>
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 set to communicate additional information about a
1134 function. Function attributes are considered to be part of the function, not
1135 of the function type, so functions with different parameter attributes can
1136 have the same function type.</p>
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1137
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1138<p>Function attributes are simple keywords that follow the type specified. If
1139 multiple attributes are needed, they are space separated. For example:</p>
Devang Patelf8b94812008-09-04 23:05:13 +0000[diff] [blame]1140
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]1141<pre class="doc_code">
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1142define void @f() noinline { ... }
1143define void @f() alwaysinline { ... }
1144define void @f() alwaysinline optsize { ... }
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1145define void @f() optsize { ... }
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1146</pre>
Devang Patelf8b94812008-09-04 23:05:13 +0000[diff] [blame]1147
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1148<dl>
Kostya Serebryany164b86b2012-01-20 17:56:17 +0000[diff] [blame]1149 <dt><tt><b>address_safety</b></tt></dt>
1150 <dd>This attribute indicates that the address safety analysis
1151 is enabled for this function. </dd>
1152
Charles Davis1e063d12010-02-12 00:31:15 +0000[diff] [blame]1153 <dt><tt><b>alignstack(&lt;<em>n</em>&gt;)</b></tt></dt>
1154 <dd>This attribute indicates that, when emitting the prologue and epilogue,
1155 the backend should forcibly align the stack pointer. Specify the
1156 desired alignment, which must be a power of two, in parentheses.
1157
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1158 <dt><tt><b>alwaysinline</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1159 <dd>This attribute indicates that the inliner should attempt to inline this
1160 function into callers whenever possible, ignoring any active inlining size
1161 threshold for this caller.</dd>
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1162
Dan Gohman129bd562011-06-16 16:03:13 +0000[diff] [blame]1163 <dt><tt><b>nonlazybind</b></tt></dt>
1164 <dd>This attribute suppresses lazy symbol binding for the function. This
1165 may make calls to the function faster, at the cost of extra program
1166 startup time if the function is not called during program startup.</dd>
1167
Jakob Stoklund Olesen570a4a52010-02-06 01:16:28 +0000[diff] [blame]1168 <dt><tt><b>inlinehint</b></tt></dt>
1169 <dd>This attribute indicates that the source code contained a hint that inlining
1170 this function is desirable (such as the "inline" keyword in C/C++). It
1171 is just a hint; it imposes no requirements on the inliner.</dd>
1172
Nick Lewycky76ec37a2010-07-06 18:24:09 +0000[diff] [blame]1173 <dt><tt><b>naked</b></tt></dt>
1174 <dd>This attribute disables prologue / epilogue emission for the function.
1175 This can have very system-specific consequences.</dd>
1176
1177 <dt><tt><b>noimplicitfloat</b></tt></dt>
1178 <dd>This attributes disables implicit floating point instructions.</dd>
1179
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1180 <dt><tt><b>noinline</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1181 <dd>This attribute indicates that the inliner should never inline this
1182 function in any situation. This attribute may not be used together with
1183 the <tt>alwaysinline</tt> attribute.</dd>
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1184
Nick Lewycky76ec37a2010-07-06 18:24:09 +0000[diff] [blame]1185 <dt><tt><b>noredzone</b></tt></dt>
1186 <dd>This attribute indicates that the code generator should not use a red
1187 zone, even if the target-specific ABI normally permits it.</dd>
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1188
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1189 <dt><tt><b>noreturn</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1190 <dd>This function attribute indicates that the function never returns
1191 normally. This produces undefined behavior at runtime if the function
1192 ever does dynamically return.</dd>
Bill Wendling31359ba2008-11-13 01:02:51 +0000[diff] [blame]1193
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1194 <dt><tt><b>nounwind</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1195 <dd>This function attribute indicates that the function never returns with an
1196 unwind or exceptional control flow. If the function does unwind, its
1197 runtime behavior is undefined.</dd>
Bill Wendlingfbaa7ed2008-11-26 19:07:40 +0000[diff] [blame]1198
Nick Lewycky76ec37a2010-07-06 18:24:09 +0000[diff] [blame]1199 <dt><tt><b>optsize</b></tt></dt>
1200 <dd>This attribute suggests that optimization passes and code generator passes
1201 make choices that keep the code size of this function low, and otherwise
1202 do optimizations specifically to reduce code size.</dd>
1203
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1204 <dt><tt><b>readnone</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1205 <dd>This attribute indicates that the function computes its result (or decides
1206 to unwind an exception) based strictly on its arguments, without
1207 dereferencing any pointer arguments or otherwise accessing any mutable
1208 state (e.g. memory, control registers, etc) visible to caller functions.
1209 It does not write through any pointer arguments
1210 (including <tt><a href="#byval">byval</a></tt> arguments) and never
1211 changes any state visible to callers. This means that it cannot unwind
Bill Wendling7b9e5392012-02-06 21:57:33 +0000[diff] [blame]1212 exceptions by calling the <tt>C++</tt> exception throwing methods.</dd>
Devang Patel5d96fda2009-06-12 19:45:19 +0000[diff] [blame]1213
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1214 <dt><tt><b><a name="readonly">readonly</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1215 <dd>This attribute indicates that the function does not write through any
1216 pointer arguments (including <tt><a href="#byval">byval</a></tt>
1217 arguments) or otherwise modify any state (e.g. memory, control registers,
1218 etc) visible to caller functions. It may dereference pointer arguments
1219 and read state that may be set in the caller. A readonly function always
1220 returns the same value (or unwinds an exception identically) when called
1221 with the same set of arguments and global state. It cannot unwind an
Bill Wendling7b9e5392012-02-06 21:57:33 +0000[diff] [blame]1222 exception by calling the <tt>C++</tt> exception throwing methods.</dd>
Anton Korobeynikovc5ec8a72009-07-17 18:07:26 +0000[diff] [blame]1223
Bill Wendling9bd5d042011-12-05 21:27:54 +0000[diff] [blame]1224 <dt><tt><b><a name="returns_twice">returns_twice</a></b></tt></dt>
1225 <dd>This attribute indicates that this function can return twice. The
1226 C <code>setjmp</code> is an example of such a function. The compiler
1227 disables some optimizations (like tail calls) in the caller of these
1228 functions.</dd>
1229
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1230 <dt><tt><b><a name="ssp">ssp</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1231 <dd>This attribute indicates that the function should emit a stack smashing
1232 protector. It is in the form of a "canary"&mdash;a random value placed on
1233 the stack before the local variables that's checked upon return from the
1234 function to see if it has been overwritten. A heuristic is used to
1235 determine if a function needs stack protectors or not.<br>
1236<br>
1237 If a function that has an <tt>ssp</tt> attribute is inlined into a
1238 function that doesn't have an <tt>ssp</tt> attribute, then the resulting
1239 function will have an <tt>ssp</tt> attribute.</dd>
1240
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1241 <dt><tt><b>sspreq</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1242 <dd>This attribute indicates that the function should <em>always</em> emit a
1243 stack smashing protector. This overrides
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1244 the <tt><a href="#ssp">ssp</a></tt> function attribute.<br>
1245<br>
1246 If a function that has an <tt>sspreq</tt> attribute is inlined into a
1247 function that doesn't have an <tt>sspreq</tt> attribute or which has
1248 an <tt>ssp</tt> attribute, then the resulting function will have
1249 an <tt>sspreq</tt> attribute.</dd>
Rafael Espindolafbff0ec2011-07-25 15:27:59 +0000[diff] [blame]1250
1251 <dt><tt><b><a name="uwtable">uwtable</a></b></tt></dt>
1252 <dd>This attribute indicates that the ABI being targeted requires that
1253 an unwind table entry be produce for this function even if we can
1254 show that no exceptions passes by it. This is normally the case for
1255 the ELF x86-64 abi, but it can be disabled for some compilation
1256 units.</dd>
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1257</dl>
1258
Devang Patelf8b94812008-09-04 23:05:13 +0000[diff] [blame]1259</div>
1260
1261<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1262<h3>
Chris Lattner1eeeb0c2006-04-08 04:40:53 +0000[diff] [blame]1263 <a name="moduleasm">Module-Level Inline Assembly</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1264</h3>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1265
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1266<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1267
1268<p>Modules may contain "module-level inline asm" blocks, which corresponds to
1269 the GCC "file scope inline asm" blocks. These blocks are internally
1270 concatenated by LLVM and treated as a single unit, but may be separated in
1271 the <tt>.ll</tt> file if desired. The syntax is very simple:</p>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1272
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]1273<pre class="doc_code">
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1274module asm "inline asm code goes here"
1275module asm "more can go here"
1276</pre>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1277
1278<p>The strings can contain any character by escaping non-printable characters.
1279 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]1280 for the number.</p>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1281
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1282<p>The inline asm code is simply printed to the machine code .s file when
1283 assembly code is generated.</p>
1284
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1285</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1286
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1287<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1288<h3>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1289 <a name="datalayout">Data Layout</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1290</h3>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1291
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1292<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1293
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1294<p>A module may specify a target specific data layout string that specifies how
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1295 data is to be laid out in memory. The syntax for the data layout is
1296 simply:</p>
1297
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]1298<pre class="doc_code">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1299target datalayout = "<i>layout specification</i>"
1300</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1301
1302<p>The <i>layout specification</i> consists of a list of specifications
1303 separated by the minus sign character ('-'). Each specification starts with
1304 a letter and may include other information after the letter to define some
1305 aspect of the data layout. The specifications accepted are as follows:</p>
1306
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1307<dl>
1308 <dt><tt>E</tt></dt>
1309 <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]1310 bits with the most significance have the lowest address location.</dd>
1311
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1312 <dt><tt>e</tt></dt>
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]1313 <dd>Specifies that the target lays out data in little-endian form. That is,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1314 the bits with the least significance have the lowest address
1315 location.</dd>
1316
Lang Hamesbb5b3f32011-10-10 23:42:08 +0000[diff] [blame]1317 <dt><tt>S<i>size</i></tt></dt>
1318 <dd>Specifies the natural alignment of the stack in bits. Alignment promotion
1319 of stack variables is limited to the natural stack alignment to avoid
1320 dynamic stack realignment. The stack alignment must be a multiple of
Lang Hames5f119a62011-10-11 17:50:14 +0000[diff] [blame]1321 8-bits. If omitted, the natural stack alignment defaults to "unspecified",
1322 which does not prevent any alignment promotions.</dd>
Lang Hamesbb5b3f32011-10-10 23:42:08 +0000[diff] [blame]1323
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1324 <dt><tt>p:<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]1325 <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]1326 <i>preferred</i> alignments. All sizes are in bits. Specifying
1327 the <i>pref</i> alignment is optional. If omitted, the
1328 preceding <tt>:</tt> should be omitted too.</dd>
1329
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1330 <dt><tt>i<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1331 <dd>This specifies the alignment for an integer type of a given bit
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1332 <i>size</i>. The value of <i>size</i> must be in the range [1,2^23).</dd>
1333
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1334 <dt><tt>v<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]1335 <dd>This specifies the alignment for a vector type of a given bit
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1336 <i>size</i>.</dd>
1337
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1338 <dt><tt>f<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]1339 <dd>This specifies the alignment for a floating point type of a given bit
Dale Johannesen9d8d2212010-05-28 18:54:47 +0000[diff] [blame]1340 <i>size</i>. Only values of <i>size</i> that are supported by the target
1341 will work. 32 (float) and 64 (double) are supported on all targets;
1342 80 or 128 (different flavors of long double) are also supported on some
1343 targets.
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1344
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1345 <dt><tt>a<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1346 <dd>This specifies the alignment for an aggregate type of a given bit
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1347 <i>size</i>.</dd>
1348
Daniel Dunbar87bde0b2009-06-08 22:17:53 +0000[diff] [blame]1349 <dt><tt>s<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1350 <dd>This specifies the alignment for a stack object of a given bit
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1351 <i>size</i>.</dd>
Chris Lattnere82bdc42009-11-07 09:35:34 +0000[diff] [blame]1352
1353 <dt><tt>n<i>size1</i>:<i>size2</i>:<i>size3</i>...</tt></dt>
1354 <dd>This specifies a set of native integer widths for the target CPU
1355 in bits. For example, it might contain "n32" for 32-bit PowerPC,
1356 "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]1357 this set are considered to support most general arithmetic
Chris Lattnere82bdc42009-11-07 09:35:34 +0000[diff] [blame]1358 operations efficiently.</dd>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1359</dl>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1360
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1361<p>When constructing the data layout for a given target, LLVM starts with a
Dan Gohman1c70c002010-04-28 00:36:01 +0000[diff] [blame]1362 default set of specifications which are then (possibly) overridden by the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1363 specifications in the <tt>datalayout</tt> keyword. The default specifications
1364 are given in this list:</p>
1365
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1366<ul>
1367 <li><tt>E</tt> - big endian</li>
Dan Gohmanfdf2e8c2010-02-23 02:44:03 +0000[diff] [blame]1368 <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]1369 <li><tt>i1:8:8</tt> - i1 is 8-bit (byte) aligned</li>
1370 <li><tt>i8:8:8</tt> - i8 is 8-bit (byte) aligned</li>
1371 <li><tt>i16:16:16</tt> - i16 is 16-bit aligned</li>
1372 <li><tt>i32:32:32</tt> - i32 is 32-bit aligned</li>
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]1373 <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]1374 alignment of 64-bits</li>
1375 <li><tt>f32:32:32</tt> - float is 32-bit aligned</li>
1376 <li><tt>f64:64:64</tt> - double is 64-bit aligned</li>
1377 <li><tt>v64:64:64</tt> - 64-bit vector is 64-bit aligned</li>
1378 <li><tt>v128:128:128</tt> - 128-bit vector is 128-bit aligned</li>
1379 <li><tt>a0:0:1</tt> - aggregates are 8-bit aligned</li>
Daniel Dunbar87bde0b2009-06-08 22:17:53 +0000[diff] [blame]1380 <li><tt>s0:64:64</tt> - stack objects are 64-bit aligned</li>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1381</ul>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1382
1383<p>When LLVM is determining the alignment for a given type, it uses the
1384 following rules:</p>
1385
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1386<ol>
1387 <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]1388 specification is used.</li>
1389
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1390 <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]1391 smallest integer type that is larger than the bitwidth of the sought type
1392 is used. If none of the specifications are larger than the bitwidth then
1393 the the largest integer type is used. For example, given the default
1394 specifications above, the i7 type will use the alignment of i8 (next
1395 largest) while both i65 and i256 will use the alignment of i64 (largest
1396 specified).</li>
1397
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1398 <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]1399 largest vector type that is smaller than the sought vector type will be
1400 used as a fall back. This happens because &lt;128 x double&gt; can be
1401 implemented in terms of 64 &lt;2 x double&gt;, for example.</li>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1402</ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1403
Chris Lattner6509f502011-10-11 23:01:39 +0000[diff] [blame]1404<p>The function of the data layout string may not be what you expect. Notably,
1405 this is not a specification from the frontend of what alignment the code
1406 generator should use.</p>
1407
1408<p>Instead, if specified, the target data layout is required to match what the
1409 ultimate <em>code generator</em> expects. This string is used by the
1410 mid-level optimizers to
1411 improve code, and this only works if it matches what the ultimate code
1412 generator uses. If you would like to generate IR that does not embed this
1413 target-specific detail into the IR, then you don't have to specify the
1414 string. This will disable some optimizations that require precise layout
1415 information, but this also prevents those optimizations from introducing
1416 target specificity into the IR.</p>
1417
1418
1419
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1420</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1421
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1422<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1423<h3>
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1424 <a name="pointeraliasing">Pointer Aliasing Rules</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1425</h3>
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1426
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1427<div>
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1428
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1429<p>Any memory access must be done through a pointer value associated
Andreas Bolka99a82052009-07-27 20:37:10 +0000[diff] [blame]1430with an address range of the memory access, otherwise the behavior
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1431is undefined. Pointer values are associated with address ranges
1432according to the following rules:</p>
1433
1434<ul>
Dan Gohman1e109622010-07-02 18:41:32 +0000[diff] [blame]1435 <li>A pointer value is associated with the addresses associated with
1436 any value it is <i>based</i> on.
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1437 <li>An address of a global variable is associated with the address
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1438 range of the variable's storage.</li>
1439 <li>The result value of an allocation instruction is associated with
1440 the address range of the allocated storage.</li>
1441 <li>A null pointer in the default address-space is associated with
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1442 no address.</li>
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1443 <li>An integer constant other than zero or a pointer value returned
1444 from a function not defined within LLVM may be associated with address
1445 ranges allocated through mechanisms other than those provided by
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1446 LLVM. Such ranges shall not overlap with any ranges of addresses
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1447 allocated by mechanisms provided by LLVM.</li>
Dan Gohman1e109622010-07-02 18:41:32 +0000[diff] [blame]1448</ul>
1449
1450<p>A pointer value is <i>based</i> on another pointer value according
1451 to the following rules:</p>
1452
1453<ul>
1454 <li>A pointer value formed from a
1455 <tt><a href="#i_getelementptr">getelementptr</a></tt> operation
1456 is <i>based</i> on the first operand of the <tt>getelementptr</tt>.</li>
1457 <li>The result value of a
1458 <tt><a href="#i_bitcast">bitcast</a></tt> is <i>based</i> on the operand
1459 of the <tt>bitcast</tt>.</li>
1460 <li>A pointer value formed by an
1461 <tt><a href="#i_inttoptr">inttoptr</a></tt> is <i>based</i> on all
1462 pointer values that contribute (directly or indirectly) to the
1463 computation of the pointer's value.</li>
1464 <li>The "<i>based</i> on" relationship is transitive.</li>
1465</ul>
1466
1467<p>Note that this definition of <i>"based"</i> is intentionally
1468 similar to the definition of <i>"based"</i> in C99, though it is
1469 slightly weaker.</p>
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1470
1471<p>LLVM IR does not associate types with memory. The result type of a
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1472<tt><a href="#i_load">load</a></tt> merely indicates the size and
1473alignment of the memory from which to load, as well as the
Dan Gohmanc22c0f32010-06-17 19:23:50 +0000[diff] [blame]1474interpretation of the value. The first operand type of a
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1475<tt><a href="#i_store">store</a></tt> similarly only indicates the size
1476and alignment of the store.</p>
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1477
1478<p>Consequently, type-based alias analysis, aka TBAA, aka
1479<tt>-fstrict-aliasing</tt>, is not applicable to general unadorned
1480LLVM IR. <a href="#metadata">Metadata</a> may be used to encode
1481additional information which specialized optimization passes may use
1482to implement type-based alias analysis.</p>
1483
1484</div>
1485
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]1486<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1487<h3>
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]1488 <a name="volatile">Volatile Memory Accesses</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1489</h3>
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]1490
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1491<div>
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]1492
1493<p>Certain memory accesses, such as <a href="#i_load"><tt>load</tt></a>s, <a
1494href="#i_store"><tt>store</tt></a>s, and <a
1495href="#int_memcpy"><tt>llvm.memcpy</tt></a>s may be marked <tt>volatile</tt>.
1496The optimizers must not change the number of volatile operations or change their
1497order of execution relative to other volatile operations. The optimizers
1498<i>may</i> change the order of volatile operations relative to non-volatile
1499operations. This is not Java's "volatile" and has no cross-thread
1500synchronization behavior.</p>
1501
1502</div>
1503
Eli Friedman5b60e1b2011-07-20 21:35:53 +0000[diff] [blame]1504<!-- ======================================================================= -->
1505<h3>
1506 <a name="memmodel">Memory Model for Concurrent Operations</a>
1507</h3>
1508
1509<div>
1510
1511<p>The LLVM IR does not define any way to start parallel threads of execution
1512or to register signal handlers. Nonetheless, there are platform-specific
1513ways to create them, and we define LLVM IR's behavior in their presence. This
1514model is inspired by the C++0x memory model.</p>
1515
Eli Friedman234bccd2011-08-22 21:35:27 +0000[diff] [blame]1516<p>For a more informal introduction to this model, see the
1517<a href="Atomics.html">LLVM Atomic Instructions and Concurrency Guide</a>.
1518
Eli Friedman5b60e1b2011-07-20 21:35:53 +0000[diff] [blame]1519<p>We define a <i>happens-before</i> partial order as the least partial order
1520that</p>
1521<ul>
1522 <li>Is a superset of single-thread program order, and</li>
1523 <li>When a <i>synchronizes-with</i> <tt>b</tt>, includes an edge from
1524 <tt>a</tt> to <tt>b</tt>. <i>Synchronizes-with</i> pairs are introduced
1525 by platform-specific techniques, like pthread locks, thread
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1526 creation, thread joining, etc., and by atomic instructions.
1527 (See also <a href="#ordering">Atomic Memory Ordering Constraints</a>).
1528 </li>
Eli Friedman5b60e1b2011-07-20 21:35:53 +0000[diff] [blame]1529</ul>
1530
1531<p>Note that program order does not introduce <i>happens-before</i> edges
1532between a thread and signals executing inside that thread.</p>
1533
1534<p>Every (defined) read operation (load instructions, memcpy, atomic
1535loads/read-modify-writes, etc.) <var>R</var> reads a series of bytes written by
1536(defined) write operations (store instructions, atomic
Eli Friedman118973a2011-07-22 03:04:45 +0000[diff] [blame]1537stores/read-modify-writes, memcpy, etc.). For the purposes of this section,
1538initialized globals are considered to have a write of the initializer which is
1539atomic and happens before any other read or write of the memory in question.
1540For each byte of a read <var>R</var>, <var>R<sub>byte</sub></var> may see
1541any write to the same byte, except:</p>
Eli Friedman5b60e1b2011-07-20 21:35:53 +0000[diff] [blame]1542
1543<ul>
1544 <li>If <var>write<sub>1</sub></var> happens before
1545 <var>write<sub>2</sub></var>, and <var>write<sub>2</sub></var> happens
1546 before <var>R<sub>byte</sub></var>, then <var>R<sub>byte</sub></var>
Eli Friedman118973a2011-07-22 03:04:45 +0000[diff] [blame]1547 does not see <var>write<sub>1</sub></var>.
Bill Wendling0246bb72011-07-31 06:45:03 +0000[diff] [blame]1548 <li>If <var>R<sub>byte</sub></var> happens before
1549 <var>write<sub>3</sub></var>, then <var>R<sub>byte</sub></var> does not
1550 see <var>write<sub>3</sub></var>.
Eli Friedman5b60e1b2011-07-20 21:35:53 +0000[diff] [blame]1551</ul>
1552
1553<p>Given that definition, <var>R<sub>byte</sub></var> is defined as follows:
1554<ul>
Eli Friedman234bccd2011-08-22 21:35:27 +0000[diff] [blame]1555 <li>If <var>R</var> is volatile, the result is target-dependent. (Volatile
1556 is supposed to give guarantees which can support
1557 <code>sig_atomic_t</code> in C/C++, and may be used for accesses to
1558 addresses which do not behave like normal memory. It does not generally
1559 provide cross-thread synchronization.)
1560 <li>Otherwise, if there is no write to the same byte that happens before
Eli Friedman5b60e1b2011-07-20 21:35:53 +0000[diff] [blame]1561 <var>R<sub>byte</sub></var>, <var>R<sub>byte</sub></var> returns
1562 <tt>undef</tt> for that byte.
Eli Friedman118973a2011-07-22 03:04:45 +0000[diff] [blame]1563 <li>Otherwise, if <var>R<sub>byte</sub></var> may see exactly one write,
Eli Friedman5b60e1b2011-07-20 21:35:53 +0000[diff] [blame]1564 <var>R<sub>byte</sub></var> returns the value written by that
1565 write.</li>
Eli Friedman118973a2011-07-22 03:04:45 +0000[diff] [blame]1566 <li>Otherwise, if <var>R</var> is atomic, and all the writes
1567 <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]1568 values written. See the <a href="#ordering">Atomic Memory Ordering
1569 Constraints</a> section for additional constraints on how the choice
1570 is made.
Eli Friedman5b60e1b2011-07-20 21:35:53 +0000[diff] [blame]1571 <li>Otherwise <var>R<sub>byte</sub></var> returns <tt>undef</tt>.</li>
1572</ul>
1573
1574<p><var>R</var> returns the value composed of the series of bytes it read.
1575This implies that some bytes within the value may be <tt>undef</tt>
1576<b>without</b> the entire value being <tt>undef</tt>. Note that this only
1577defines the semantics of the operation; it doesn't mean that targets will
1578emit more than one instruction to read the series of bytes.</p>
1579
1580<p>Note that in cases where none of the atomic intrinsics are used, this model
1581places only one restriction on IR transformations on top of what is required
1582for single-threaded execution: introducing a store to a byte which might not
Eli Friedman101c81d2011-08-02 01:15:34 +0000[diff] [blame]1583otherwise be stored is not allowed in general. (Specifically, in the case
1584where another thread might write to and read from an address, introducing a
1585store can change a load that may see exactly one write into a load that may
1586see multiple writes.)</p>
Eli Friedman5b60e1b2011-07-20 21:35:53 +0000[diff] [blame]1587
1588<!-- FIXME: This model assumes all targets where concurrency is relevant have
1589a byte-size store which doesn't affect adjacent bytes. As far as I can tell,
1590none of the backends currently in the tree fall into this category; however,
1591there might be targets which care. If there are, we want a paragraph
1592like the following:
1593
1594Targets may specify that stores narrower than a certain width are not
1595available; on such a target, for the purposes of this model, treat any
1596non-atomic write with an alignment or width less than the minimum width
1597as if it writes to the relevant surrounding bytes.
1598-->
1599
1600</div>
1601
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1602<!-- ======================================================================= -->
NAKAMURA Takumib5bb29c2011-08-12 06:17:17 +0000[diff] [blame]1603<h3>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1604 <a name="ordering">Atomic Memory Ordering Constraints</a>
NAKAMURA Takumib5bb29c2011-08-12 06:17:17 +0000[diff] [blame]1605</h3>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1606
NAKAMURA Takumib5bb29c2011-08-12 06:17:17 +0000[diff] [blame]1607<div>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1608
1609<p>Atomic instructions (<a href="#i_cmpxchg"><code>cmpxchg</code></a>,
Eli Friedman21006d42011-08-09 23:02:53 +0000[diff] [blame]1610<a href="#i_atomicrmw"><code>atomicrmw</code></a>,
1611<a href="#i_fence"><code>fence</code></a>,
1612<a href="#i_load"><code>atomic load</code></a>, and
Eli Friedman8fa281a2011-08-09 23:26:12 +0000[diff] [blame]1613<a href="#i_store"><code>atomic store</code></a>) take an ordering parameter
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1614that determines which other atomic instructions on the same address they
1615<i>synchronize with</i>. These semantics are borrowed from Java and C++0x,
1616but are somewhat more colloquial. If these descriptions aren't precise enough,
Eli Friedman234bccd2011-08-22 21:35:27 +0000[diff] [blame]1617check those specs (see spec references in the
Nick Lewycky300a2632012-01-23 08:47:21 +0000[diff] [blame]1618<a href="Atomics.html#introduction">atomics guide</a>).
Eli Friedman234bccd2011-08-22 21:35:27 +0000[diff] [blame]1619<a href="#i_fence"><code>fence</code></a> instructions
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1620treat these orderings somewhat differently since they don't take an address.
1621See that instruction's documentation for details.</p>
1622
Eli Friedman234bccd2011-08-22 21:35:27 +0000[diff] [blame]1623<p>For a simpler introduction to the ordering constraints, see the
1624<a href="Atomics.html">LLVM Atomic Instructions and Concurrency Guide</a>.</p>
1625
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1626<dl>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1627<dt><code>unordered</code></dt>
1628<dd>The set of values that can be read is governed by the happens-before
1629partial order. A value cannot be read unless some operation wrote it.
1630This is intended to provide a guarantee strong enough to model Java's
1631non-volatile shared variables. This ordering cannot be specified for
1632read-modify-write operations; it is not strong enough to make them atomic
1633in any interesting way.</dd>
1634<dt><code>monotonic</code></dt>
1635<dd>In addition to the guarantees of <code>unordered</code>, there is a single
1636total order for modifications by <code>monotonic</code> operations on each
1637address. All modification orders must be compatible with the happens-before
1638order. There is no guarantee that the modification orders can be combined to
1639a global total order for the whole program (and this often will not be
1640possible). The read in an atomic read-modify-write operation
1641(<a href="#i_cmpxchg"><code>cmpxchg</code></a> and
1642<a href="#i_atomicrmw"><code>atomicrmw</code></a>)
1643reads the value in the modification order immediately before the value it
1644writes. If one atomic read happens before another atomic read of the same
1645address, the later read must see the same value or a later value in the
1646address's modification order. This disallows reordering of
1647<code>monotonic</code> (or stronger) operations on the same address. If an
1648address is written <code>monotonic</code>ally by one thread, and other threads
1649<code>monotonic</code>ally read that address repeatedly, the other threads must
Eli Friedman234bccd2011-08-22 21:35:27 +0000[diff] [blame]1650eventually see the write. This corresponds to the C++0x/C1x
1651<code>memory_order_relaxed</code>.</dd>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1652<dt><code>acquire</code></dt>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1653<dd>In addition to the guarantees of <code>monotonic</code>,
Eli Friedmanc264b2f2011-08-24 20:28:39 +0000[diff] [blame]1654a <i>synchronizes-with</i> edge may be formed with a <code>release</code>
1655operation. This is intended to model C++'s <code>memory_order_acquire</code>.</dd>
1656<dt><code>release</code></dt>
1657<dd>In addition to the guarantees of <code>monotonic</code>, if this operation
1658writes a value which is subsequently read by an <code>acquire</code> operation,
1659it <i>synchronizes-with</i> that operation. (This isn't a complete
1660description; see the C++0x definition of a release sequence.) This corresponds
1661to the C++0x/C1x <code>memory_order_release</code>.</dd>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1662<dt><code>acq_rel</code> (acquire+release)</dt><dd>Acts as both an
Eli Friedman234bccd2011-08-22 21:35:27 +0000[diff] [blame]1663<code>acquire</code> and <code>release</code> operation on its address.
1664This corresponds to the C++0x/C1x <code>memory_order_acq_rel</code>.</dd>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1665<dt><code>seq_cst</code> (sequentially consistent)</dt><dd>
1666<dd>In addition to the guarantees of <code>acq_rel</code>
1667(<code>acquire</code> for an operation which only reads, <code>release</code>
1668for an operation which only writes), there is a global total order on all
1669sequentially-consistent operations on all addresses, which is consistent with
1670the <i>happens-before</i> partial order and with the modification orders of
1671all the affected addresses. Each sequentially-consistent read sees the last
Eli Friedman234bccd2011-08-22 21:35:27 +0000[diff] [blame]1672preceding write to the same address in this global order. This corresponds
1673to the C++0x/C1x <code>memory_order_seq_cst</code> and Java volatile.</dd>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1674</dl>
1675
1676<p id="singlethread">If an atomic operation is marked <code>singlethread</code>,
1677it only <i>synchronizes with</i> or participates in modification and seq_cst
1678total orderings with other operations running in the same thread (for example,
1679in signal handlers).</p>
1680
1681</div>
1682
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1683</div>
1684
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1685<!-- *********************************************************************** -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1686<h2><a name="typesystem">Type System</a></h2>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1687<!-- *********************************************************************** -->
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1688
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1689<div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1690
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1691<p>The LLVM type system is one of the most important features of the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1692 intermediate representation. Being typed enables a number of optimizations
1693 to be performed on the intermediate representation directly, without having
1694 to do extra analyses on the side before the transformation. A strong type
1695 system makes it easier to read the generated code and enables novel analyses
1696 and transformations that are not feasible to perform on normal three address
1697 code representations.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1698
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1699<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1700<h3>
1701 <a name="t_classifications">Type Classifications</a>
1702</h3>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1703
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1704<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1705
1706<p>The types fall into a few useful classifications:</p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1707
1708<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1709 <tbody>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1710 <tr><th>Classification</th><th>Types</th></tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1711 <tr>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1712 <td><a href="#t_integer">integer</a></td>
Reid Spencer2b916312007-05-16 18:44:01 +0000[diff] [blame]1713 <td><tt>i1, i2, i3, ... i8, ... i16, ... i32, ... i64, ... </tt></td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1714 </tr>
1715 <tr>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1716 <td><a href="#t_floating">floating point</a></td>
Dan Gohmance163392011-12-17 00:04:22 +0000[diff] [blame]1717 <td><tt>half, float, double, x86_fp80, fp128, ppc_fp128</tt></td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1718 </tr>
1719 <tr>
1720 <td><a name="t_firstclass">first class</a></td>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1721 <td><a href="#t_integer">integer</a>,
1722 <a href="#t_floating">floating point</a>,
1723 <a href="#t_pointer">pointer</a>,
Dan Gohman0066db62008-06-18 18:42:13 +0000[diff] [blame]1724 <a href="#t_vector">vector</a>,
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]1725 <a href="#t_struct">structure</a>,
1726 <a href="#t_array">array</a>,
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1727 <a href="#t_label">label</a>,
1728 <a href="#t_metadata">metadata</a>.
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1729 </td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1730 </tr>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1731 <tr>
1732 <td><a href="#t_primitive">primitive</a></td>
1733 <td><a href="#t_label">label</a>,
1734 <a href="#t_void">void</a>,
Tobias Grosser05387292010-12-28 20:29:31 +0000[diff] [blame]1735 <a href="#t_integer">integer</a>,
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1736 <a href="#t_floating">floating point</a>,
Dale Johannesen21fe99b2010-10-01 00:48:59 +0000[diff] [blame]1737 <a href="#t_x86mmx">x86mmx</a>,
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1738 <a href="#t_metadata">metadata</a>.</td>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1739 </tr>
1740 <tr>
1741 <td><a href="#t_derived">derived</a></td>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]1742 <td><a href="#t_array">array</a>,
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1743 <a href="#t_function">function</a>,
1744 <a href="#t_pointer">pointer</a>,
1745 <a href="#t_struct">structure</a>,
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1746 <a href="#t_vector">vector</a>,
1747 <a href="#t_opaque">opaque</a>.
Dan Gohman01ac1012008-10-14 16:32:04 +0000[diff] [blame]1748 </td>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1749 </tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1750 </tbody>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1751</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1752
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1753<p>The <a href="#t_firstclass">first class</a> types are perhaps the most
1754 important. Values of these types are the only ones which can be produced by
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]1755 instructions.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1756
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1757</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1758
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1759<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1760<h3>
1761 <a name="t_primitive">Primitive Types</a>
1762</h3>
Chris Lattner8f8c7b72008-01-04 04:34:14 +0000[diff] [blame]1763
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1764<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1765
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1766<p>The primitive types are the fundamental building blocks of the LLVM
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1767 system.</p>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1768
1769<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1770<h4>
1771 <a name="t_integer">Integer Type</a>
1772</h4>
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]1773
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1774<div>
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]1775
1776<h5>Overview:</h5>
1777<p>The integer type is a very simple type that simply specifies an arbitrary
1778 bit width for the integer type desired. Any bit width from 1 bit to
1779 2<sup>23</sup>-1 (about 8 million) can be specified.</p>
1780
1781<h5>Syntax:</h5>
1782<pre>
1783 iN
1784</pre>
1785
1786<p>The number of bits the integer will occupy is specified by the <tt>N</tt>
1787 value.</p>
1788
1789<h5>Examples:</h5>
1790<table class="layout">
1791 <tr class="layout">
1792 <td class="left"><tt>i1</tt></td>
1793 <td class="left">a single-bit integer.</td>
1794 </tr>
1795 <tr class="layout">
1796 <td class="left"><tt>i32</tt></td>
1797 <td class="left">a 32-bit integer.</td>
1798 </tr>
1799 <tr class="layout">
1800 <td class="left"><tt>i1942652</tt></td>
1801 <td class="left">a really big integer of over 1 million bits.</td>
1802 </tr>
1803</table>
1804
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]1805</div>
1806
1807<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1808<h4>
1809 <a name="t_floating">Floating Point Types</a>
1810</h4>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1811
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1812<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1813
1814<table>
1815 <tbody>
1816 <tr><th>Type</th><th>Description</th></tr>
Dan Gohmance163392011-12-17 00:04:22 +0000[diff] [blame]1817 <tr><td><tt>half</tt></td><td>16-bit floating point value</td></tr>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1818 <tr><td><tt>float</tt></td><td>32-bit floating point value</td></tr>
1819 <tr><td><tt>double</tt></td><td>64-bit floating point value</td></tr>
1820 <tr><td><tt>fp128</tt></td><td>128-bit floating point value (112-bit mantissa)</td></tr>
1821 <tr><td><tt>x86_fp80</tt></td><td>80-bit floating point value (X87)</td></tr>
1822 <tr><td><tt>ppc_fp128</tt></td><td>128-bit floating point value (two 64-bits)</td></tr>
1823 </tbody>
1824</table>
1825
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1826</div>
1827
1828<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1829<h4>
1830 <a name="t_x86mmx">X86mmx Type</a>
1831</h4>
Dale Johannesen21fe99b2010-10-01 00:48:59 +0000[diff] [blame]1832
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1833<div>
Dale Johannesen21fe99b2010-10-01 00:48:59 +0000[diff] [blame]1834
1835<h5>Overview:</h5>
1836<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>
1837
1838<h5>Syntax:</h5>
1839<pre>
Dale Johannesen473a8c82010-10-01 01:07:02 +0000[diff] [blame]1840 x86mmx
Dale Johannesen21fe99b2010-10-01 00:48:59 +0000[diff] [blame]1841</pre>
1842
1843</div>
1844
1845<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1846<h4>
1847 <a name="t_void">Void Type</a>
1848</h4>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1849
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1850<div>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1851
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1852<h5>Overview:</h5>
1853<p>The void type does not represent any value and has no size.</p>
1854
1855<h5>Syntax:</h5>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1856<pre>
1857 void
1858</pre>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1859
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1860</div>
1861
1862<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1863<h4>
1864 <a name="t_label">Label Type</a>
1865</h4>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1866
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1867<div>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1868
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1869<h5>Overview:</h5>
1870<p>The label type represents code labels.</p>
1871
1872<h5>Syntax:</h5>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1873<pre>
1874 label
1875</pre>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1876
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1877</div>
1878
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1879<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1880<h4>
1881 <a name="t_metadata">Metadata Type</a>
1882</h4>
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1883
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1884<div>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1885
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1886<h5>Overview:</h5>
Nick Lewyckyc261df92009-09-27 23:27:42 +0000[diff] [blame]1887<p>The metadata type represents embedded metadata. No derived types may be
1888 created from metadata except for <a href="#t_function">function</a>
1889 arguments.
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1890
1891<h5>Syntax:</h5>
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1892<pre>
1893 metadata
1894</pre>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1895
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1896</div>
1897
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1898</div>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1899
1900<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1901<h3>
1902 <a name="t_derived">Derived Types</a>
1903</h3>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1904
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1905<div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1906
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1907<p>The real power in LLVM comes from the derived types in the system. This is
1908 what allows a programmer to represent arrays, functions, pointers, and other
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]1909 useful types. Each of these types contain one or more element types which
1910 may be a primitive type, or another derived type. For example, it is
1911 possible to have a two dimensional array, using an array as the element type
1912 of another array.</p>
Dan Gohmand8791e52009-01-24 15:58:40 +0000[diff] [blame]1913
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]1914<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1915<h4>
1916 <a name="t_aggregate">Aggregate Types</a>
1917</h4>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]1918
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1919<div>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]1920
1921<p>Aggregate Types are a subset of derived types that can contain multiple
Duncan Sands20536b52011-12-14 15:44:20 +0000[diff] [blame]1922 member types. <a href="#t_array">Arrays</a> and
1923 <a href="#t_struct">structs</a> are aggregate types.
1924 <a href="#t_vector">Vectors</a> are not considered to be aggregate types.</p>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]1925
1926</div>
1927
Reid Spencer2b916312007-05-16 18:44:01 +0000[diff] [blame]1928<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1929<h4>
1930 <a name="t_array">Array Type</a>
1931</h4>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1932
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1933<div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1934
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1935<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1936<p>The array type is a very simple derived type that arranges elements
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1937 sequentially in memory. The array type requires a size (number of elements)
1938 and an underlying data type.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1939
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1940<h5>Syntax:</h5>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1941<pre>
1942 [&lt;# elements&gt; x &lt;elementtype&gt;]
1943</pre>
1944
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1945<p>The number of elements is a constant integer value; <tt>elementtype</tt> may
1946 be any type with a size.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1947
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1948<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1949<table class="layout">
1950 <tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1951 <td class="left"><tt>[40 x i32]</tt></td>
1952 <td class="left">Array of 40 32-bit integer values.</td>
1953 </tr>
1954 <tr class="layout">
1955 <td class="left"><tt>[41 x i32]</tt></td>
1956 <td class="left">Array of 41 32-bit integer values.</td>
1957 </tr>
1958 <tr class="layout">
1959 <td class="left"><tt>[4 x i8]</tt></td>
1960 <td class="left">Array of 4 8-bit integer values.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1961 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1962</table>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1963<p>Here are some examples of multidimensional arrays:</p>
1964<table class="layout">
1965 <tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1966 <td class="left"><tt>[3 x [4 x i32]]</tt></td>
1967 <td class="left">3x4 array of 32-bit integer values.</td>
1968 </tr>
1969 <tr class="layout">
1970 <td class="left"><tt>[12 x [10 x float]]</tt></td>
1971 <td class="left">12x10 array of single precision floating point values.</td>
1972 </tr>
1973 <tr class="layout">
1974 <td class="left"><tt>[2 x [3 x [4 x i16]]]</tt></td>
1975 <td class="left">2x3x4 array of 16-bit integer values.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1976 </tr>
1977</table>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]1978
Dan Gohman7657f6b2009-11-09 19:01:53 +0000[diff] [blame]1979<p>There is no restriction on indexing beyond the end of the array implied by
1980 a static type (though there are restrictions on indexing beyond the bounds
1981 of an allocated object in some cases). This means that single-dimension
1982 'variable sized array' addressing can be implemented in LLVM with a zero
1983 length array type. An implementation of 'pascal style arrays' in LLVM could
1984 use the type "<tt>{ i32, [0 x float]}</tt>", for example.</p>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]1985
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1986</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1987
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1988<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1989<h4>
1990 <a name="t_function">Function Type</a>
1991</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1992
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1993<div>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]1994
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1995<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1996<p>The function type can be thought of as a function signature. It consists of
1997 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]1998 function type is a first class type or a void type.</p>
Devang Patelc3fc6df2008-03-10 20:49:15 +0000[diff] [blame]1999
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2000<h5>Syntax:</h5>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]2001<pre>
Nick Lewycky51386942009-09-27 07:55:32 +0000[diff] [blame]2002 &lt;returntype&gt; (&lt;parameter list&gt;)
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]2003</pre>
2004
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]2005<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]2006 specifiers. Optionally, the parameter list may include a type <tt>...</tt>,
2007 which indicates that the function takes a variable number of arguments.
2008 Variable argument functions can access their arguments with
2009 the <a href="#int_varargs">variable argument handling intrinsic</a>
Chris Lattner0724fbd2010-03-02 06:36:51 +0000[diff] [blame]2010 functions. '<tt>&lt;returntype&gt;</tt>' is any type except
Nick Lewyckyc261df92009-09-27 23:27:42 +0000[diff] [blame]2011 <a href="#t_label">label</a>.</p>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]2012
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2013<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]2014<table class="layout">
2015 <tr class="layout">
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]2016 <td class="left"><tt>i32 (i32)</tt></td>
2017 <td class="left">function taking an <tt>i32</tt>, returning an <tt>i32</tt>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]2018 </td>
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]2019 </tr><tr class="layout">
Chris Lattner0724fbd2010-03-02 06:36:51 +0000[diff] [blame]2020 <td class="left"><tt>float&nbsp;(i16,&nbsp;i32&nbsp;*)&nbsp;*
Reid Spencerf17a0b72006-12-31 07:20:23 +0000[diff] [blame]2021 </tt></td>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]2022 <td class="left"><a href="#t_pointer">Pointer</a> to a function that takes
Chris Lattner0724fbd2010-03-02 06:36:51 +0000[diff] [blame]2023 an <tt>i16</tt> and a <a href="#t_pointer">pointer</a> to <tt>i32</tt>,
2024 returning <tt>float</tt>.
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]2025 </td>
2026 </tr><tr class="layout">
2027 <td class="left"><tt>i32 (i8*, ...)</tt></td>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]2028 <td class="left">A vararg function that takes at least one
2029 <a href="#t_pointer">pointer</a> to <tt>i8 </tt> (char in C),
2030 which returns an integer. This is the signature for <tt>printf</tt> in
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]2031 LLVM.
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]2032 </td>
Devang Patela582f402008-03-24 05:35:41 +0000[diff] [blame]2033 </tr><tr class="layout">
2034 <td class="left"><tt>{i32, i32} (i32)</tt></td>
Nick Lewycky51386942009-09-27 07:55:32 +0000[diff] [blame]2035 <td class="left">A function taking an <tt>i32</tt>, returning a
2036 <a href="#t_struct">structure</a> containing two <tt>i32</tt> values
Devang Patela582f402008-03-24 05:35:41 +0000[diff] [blame]2037 </td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]2038 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2039</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]2040
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2041</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2042
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2043<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2044<h4>
2045 <a name="t_struct">Structure Type</a>
2046</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2047
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2048<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2049
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2050<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2051<p>The structure type is used to represent a collection of data members together
Chris Lattner1afcace2011-07-09 17:41:24 +0000[diff] [blame]2052 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]2053
Jeffrey Yasskin7a088cf2010-01-11 19:19:26 +0000[diff] [blame]2054<p>Structures in memory are accessed using '<tt><a href="#i_load">load</a></tt>'
2055 and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a field
2056 with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.
2057 Structures in registers are accessed using the
2058 '<tt><a href="#i_extractvalue">extractvalue</a></tt>' and
2059 '<tt><a href="#i_insertvalue">insertvalue</a></tt>' instructions.</p>
Chris Lattner1afcace2011-07-09 17:41:24 +0000[diff] [blame]2060
2061<p>Structures may optionally be "packed" structures, which indicate that the
2062 alignment of the struct is one byte, and that there is no padding between
Chris Lattner2c38d652011-08-12 17:31:02 +0000[diff] [blame]2063 the elements. In non-packed structs, padding between field types is inserted
2064 as defined by the TargetData string in the module, which is required to match
Chris Lattnere4617b02011-10-11 23:02:17 +0000[diff] [blame]2065 what the underlying code generator expects.</p>
Chris Lattner1afcace2011-07-09 17:41:24 +0000[diff] [blame]2066
Chris Lattner2c38d652011-08-12 17:31:02 +0000[diff] [blame]2067<p>Structures can either be "literal" or "identified". A literal structure is
2068 defined inline with other types (e.g. <tt>{i32, i32}*</tt>) whereas identified
2069 types are always defined at the top level with a name. Literal types are
2070 uniqued by their contents and can never be recursive or opaque since there is
Chris Lattneraa175c32011-08-12 18:12:40 +0000[diff] [blame]2071 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]2072 never uniqued.
Chris Lattner1afcace2011-07-09 17:41:24 +0000[diff] [blame]2073</p>
2074
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2075<h5>Syntax:</h5>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]2076<pre>
Chris Lattner2c38d652011-08-12 17:31:02 +0000[diff] [blame]2077 %T1 = type { &lt;type list&gt; } <i>; Identified normal struct type</i>
2078 %T2 = type &lt;{ &lt;type list&gt; }&gt; <i>; Identified packed struct type</i>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]2079</pre>
Chris Lattner1afcace2011-07-09 17:41:24 +0000[diff] [blame]2080
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2081<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]2082<table class="layout">
2083 <tr class="layout">
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]2084 <td class="left"><tt>{ i32, i32, i32 }</tt></td>
2085 <td class="left">A triple of three <tt>i32</tt> values</td>
Chris Lattner1afcace2011-07-09 17:41:24 +0000[diff] [blame]2086 </tr>
2087 <tr class="layout">
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]2088 <td class="left"><tt>{&nbsp;float,&nbsp;i32&nbsp;(i32)&nbsp;*&nbsp;}</tt></td>
2089 <td class="left">A pair, where the first element is a <tt>float</tt> and the
2090 second element is a <a href="#t_pointer">pointer</a> to a
2091 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
2092 an <tt>i32</tt>.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]2093 </tr>
Chris Lattner1afcace2011-07-09 17:41:24 +0000[diff] [blame]2094 <tr class="layout">
2095 <td class="left"><tt>&lt;{ i8, i32 }&gt;</tt></td>
2096 <td class="left">A packed struct known to be 5 bytes in size.</td>
2097 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2098</table>
Dan Gohmand8791e52009-01-24 15:58:40 +0000[diff] [blame]2099
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2100</div>
Chris Lattner1afcace2011-07-09 17:41:24 +0000[diff] [blame]2101
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2102<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2103<h4>
Chris Lattner628ed392011-07-23 19:59:08 +0000[diff] [blame]2104 <a name="t_opaque">Opaque Structure Types</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2105</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2106
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2107<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2108
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]2109<h5>Overview:</h5>
Chris Lattner628ed392011-07-23 19:59:08 +0000[diff] [blame]2110<p>Opaque structure types are used to represent named structure types that do
2111 not have a body specified. This corresponds (for example) to the C notion of
2112 a forward declared structure.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2113
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]2114<h5>Syntax:</h5>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]2115<pre>
Chris Lattner1afcace2011-07-09 17:41:24 +0000[diff] [blame]2116 %X = type opaque
2117 %52 = type opaque
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]2118</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2119
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]2120<h5>Examples:</h5>
2121<table class="layout">
2122 <tr class="layout">
Chris Lattner1afcace2011-07-09 17:41:24 +0000[diff] [blame]2123 <td class="left"><tt>opaque</tt></td>
2124 <td class="left">An opaque type.</td>
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]2125 </tr>
2126</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2127
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]2128</div>
2129
Chris Lattner1afcace2011-07-09 17:41:24 +0000[diff] [blame]2130
2131
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]2132<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2133<h4>
2134 <a name="t_pointer">Pointer Type</a>
2135</h4>
Chris Lattner0fd4a272009-02-08 19:53:29 +0000[diff] [blame]2136
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2137<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2138
2139<h5>Overview:</h5>
Dan Gohmanff3ef322010-02-25 16:50:07 +0000[diff] [blame]2140<p>The pointer type is used to specify memory locations.
2141 Pointers are commonly used to reference objects in memory.</p>
2142
2143<p>Pointer types may have an optional address space attribute defining the
2144 numbered address space where the pointed-to object resides. The default
2145 address space is number zero. The semantics of non-zero address
2146 spaces are target-specific.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2147
2148<p>Note that LLVM does not permit pointers to void (<tt>void*</tt>) nor does it
2149 permit pointers to labels (<tt>label*</tt>). Use <tt>i8*</tt> instead.</p>
Chris Lattner0fd4a272009-02-08 19:53:29 +0000[diff] [blame]2150
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2151<h5>Syntax:</h5>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]2152<pre>
2153 &lt;type&gt; *
2154</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2155
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2156<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]2157<table class="layout">
2158 <tr class="layout">
Dan Gohman2a08c532009-01-04 23:44:43 +0000[diff] [blame]2159 <td class="left"><tt>[4 x 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
2161 href="#t_array">array</a> of four <tt>i32</tt> values.</td>
2162 </tr>
2163 <tr class="layout">
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]2164 <td class="left"><tt>i32 (i32*) *</tt></td>
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]2165 <td class="left"> A <a href="#t_pointer">pointer</a> to a <a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2166 href="#t_function">function</a> that takes an <tt>i32*</tt>, returning an
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]2167 <tt>i32</tt>.</td>
2168 </tr>
2169 <tr class="layout">
2170 <td class="left"><tt>i32 addrspace(5)*</tt></td>
2171 <td class="left">A <a href="#t_pointer">pointer</a> to an <tt>i32</tt> value
2172 that resides in address space #5.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]2173 </tr>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2174</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2175
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2176</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]2177
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]2178<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2179<h4>
2180 <a name="t_vector">Vector Type</a>
2181</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2182
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2183<div>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]2184
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]2185<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2186<p>A vector type is a simple derived type that represents a vector of elements.
2187 Vector types are used when multiple primitive data are operated in parallel
2188 using a single instruction (SIMD). A vector type requires a size (number of
Duncan Sandsd40d14e2009-11-27 13:38:03 +0000[diff] [blame]2189 elements) and an underlying primitive data type. Vector types are considered
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2190 <a href="#t_firstclass">first class</a>.</p>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]2191
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]2192<h5>Syntax:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]2193<pre>
2194 &lt; &lt;# elements&gt; x &lt;elementtype&gt; &gt;
2195</pre>
2196
Chris Lattner7d2e7be2010-10-10 18:20:35 +0000[diff] [blame]2197<p>The number of elements is a constant integer value larger than 0; elementtype
Nadav Rotem16087692011-12-05 06:29:09 +0000[diff] [blame]2198 may be any integer or floating point type, or a pointer to these types.
2199 Vectors of size zero are not allowed. </p>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]2200
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]2201<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]2202<table class="layout">
2203 <tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]2204 <td class="left"><tt>&lt;4 x i32&gt;</tt></td>
2205 <td class="left">Vector of 4 32-bit integer values.</td>
2206 </tr>
2207 <tr class="layout">
2208 <td class="left"><tt>&lt;8 x float&gt;</tt></td>
2209 <td class="left">Vector of 8 32-bit floating-point values.</td>
2210 </tr>
2211 <tr class="layout">
2212 <td class="left"><tt>&lt;2 x i64&gt;</tt></td>
2213 <td class="left">Vector of 2 64-bit integer values.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]2214 </tr>
Nadav Rotem16087692011-12-05 06:29:09 +0000[diff] [blame]2215 <tr class="layout">
2216 <td class="left"><tt>&lt;4 x i64*&gt;</tt></td>
2217 <td class="left">Vector of 4 pointers to 64-bit integer values.</td>
2218 </tr>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]2219</table>
Dan Gohmand8791e52009-01-24 15:58:40 +0000[diff] [blame]2220
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2221</div>
2222
Bill Wendlingaf75f0c2011-07-31 06:47:33 +0000[diff] [blame]2223</div>
2224
NAKAMURA Takumi4b2e07a2011-10-31 13:04:26 +0000[diff] [blame]2225</div>
2226
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2227<!-- *********************************************************************** -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2228<h2><a name="constants">Constants</a></h2>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2229<!-- *********************************************************************** -->
2230
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2231<div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2232
2233<p>LLVM has several different basic types of constants. This section describes
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2234 them all and their syntax.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2235
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2236<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2237<h3>
2238 <a name="simpleconstants">Simple Constants</a>
2239</h3>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2240
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2241<div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2242
2243<dl>
2244 <dt><b>Boolean constants</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2245 <dd>The two strings '<tt>true</tt>' and '<tt>false</tt>' are both valid
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]2246 constants of the <tt><a href="#t_integer">i1</a></tt> type.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2247
2248 <dt><b>Integer constants</b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2249 <dd>Standard integers (such as '4') are constants of
2250 the <a href="#t_integer">integer</a> type. Negative numbers may be used
2251 with integer types.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2252
2253 <dt><b>Floating point constants</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2254 <dd>Floating point constants use standard decimal notation (e.g. 123.421),
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2255 exponential notation (e.g. 1.23421e+2), or a more precise hexadecimal
2256 notation (see below). The assembler requires the exact decimal value of a
2257 floating-point constant. For example, the assembler accepts 1.25 but
2258 rejects 1.3 because 1.3 is a repeating decimal in binary. Floating point
2259 constants must have a <a href="#t_floating">floating point</a> type. </dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2260
2261 <dt><b>Null pointer constants</b></dt>
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]2262 <dd>The identifier '<tt>null</tt>' is recognized as a null pointer constant
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2263 and must be of <a href="#t_pointer">pointer type</a>.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2264</dl>
2265
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2266<p>The one non-intuitive notation for constants is the hexadecimal form of
2267 floating point constants. For example, the form '<tt>double
2268 0x432ff973cafa8000</tt>' is equivalent to (but harder to read than)
2269 '<tt>double 4.5e+15</tt>'. The only time hexadecimal floating point
2270 constants are required (and the only time that they are generated by the
2271 disassembler) is when a floating point constant must be emitted but it cannot
2272 be represented as a decimal floating point number in a reasonable number of
2273 digits. For example, NaN's, infinities, and other special values are
2274 represented in their IEEE hexadecimal format so that assembly and disassembly
2275 do not cause any bits to change in the constants.</p>
2276
Dan Gohmance163392011-12-17 00:04:22 +0000[diff] [blame]2277<p>When using the hexadecimal form, constants of types half, float, and double are
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2278 represented using the 16-digit form shown above (which matches the IEEE754
Dan Gohmance163392011-12-17 00:04:22 +0000[diff] [blame]2279 representation for double); half and float values must, however, be exactly
2280 representable as IEE754 half and single precision, respectively.
2281 Hexadecimal format is always used
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2282 for long double, and there are three forms of long double. The 80-bit format
2283 used by x86 is represented as <tt>0xK</tt> followed by 20 hexadecimal digits.
2284 The 128-bit format used by PowerPC (two adjacent doubles) is represented
2285 by <tt>0xM</tt> followed by 32 hexadecimal digits. The IEEE 128-bit format
2286 is represented by <tt>0xL</tt> followed by 32 hexadecimal digits; no
2287 currently supported target uses this format. Long doubles will only work if
2288 they match the long double format on your target. All hexadecimal formats
2289 are big-endian (sign bit at the left).</p>
2290
Dale Johannesen21fe99b2010-10-01 00:48:59 +0000[diff] [blame]2291<p>There are no constants of type x86mmx.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2292</div>
2293
2294<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2295<h3>
Bill Wendlingd9fe2982009-07-20 02:32:41 +0000[diff] [blame]2296<a name="aggregateconstants"></a> <!-- old anchor -->
2297<a name="complexconstants">Complex Constants</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2298</h3>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2299
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2300<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2301
Chris Lattner70882792009-02-28 18:32:25 +0000[diff] [blame]2302<p>Complex constants are a (potentially recursive) combination of simple
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2303 constants and smaller complex constants.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2304
2305<dl>
2306 <dt><b>Structure constants</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2307 <dd>Structure constants are represented with notation similar to structure
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2308 type definitions (a comma separated list of elements, surrounded by braces
2309 (<tt>{}</tt>)). For example: "<tt>{ i32 4, float 17.0, i32* @G }</tt>",
2310 where "<tt>@G</tt>" is declared as "<tt>@G = external global i32</tt>".
2311 Structure constants must have <a href="#t_struct">structure type</a>, and
2312 the number and types of elements must match those specified by the
2313 type.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2314
2315 <dt><b>Array constants</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2316 <dd>Array constants are represented with notation similar to array type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2317 definitions (a comma separated list of elements, surrounded by square
2318 brackets (<tt>[]</tt>)). For example: "<tt>[ i32 42, i32 11, i32 74
2319 ]</tt>". Array constants must have <a href="#t_array">array type</a>, and
2320 the number and types of elements must match those specified by the
2321 type.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2322
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2323 <dt><b>Vector constants</b></dt>
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2324 <dd>Vector constants are represented with notation similar to vector type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2325 definitions (a comma separated list of elements, surrounded by
2326 less-than/greater-than's (<tt>&lt;&gt;</tt>)). For example: "<tt>&lt; i32
2327 42, i32 11, i32 74, i32 100 &gt;</tt>". Vector constants must
2328 have <a href="#t_vector">vector type</a>, and the number and types of
2329 elements must match those specified by the type.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2330
2331 <dt><b>Zero initialization</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2332 <dd>The string '<tt>zeroinitializer</tt>' can be used to zero initialize a
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]2333 value to zero of <em>any</em> type, including scalar and
2334 <a href="#t_aggregate">aggregate</a> types.
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2335 This is often used to avoid having to print large zero initializers
2336 (e.g. for large arrays) and is always exactly equivalent to using explicit
2337 zero initializers.</dd>
Nick Lewycky21cc4462009-04-04 07:22:01 +0000[diff] [blame]2338
2339 <dt><b>Metadata node</b></dt>
Nick Lewycky1e8c7a62009-05-30 16:08:30 +0000[diff] [blame]2340 <dd>A metadata node is a structure-like constant with
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2341 <a href="#t_metadata">metadata type</a>. For example: "<tt>metadata !{
2342 i32 0, metadata !"test" }</tt>". Unlike other constants that are meant to
2343 be interpreted as part of the instruction stream, metadata is a place to
2344 attach additional information such as debug info.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2345</dl>
2346
2347</div>
2348
2349<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2350<h3>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2351 <a name="globalconstants">Global Variable and Function Addresses</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2352</h3>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2353
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2354<div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2355
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2356<p>The addresses of <a href="#globalvars">global variables</a>
2357 and <a href="#functionstructure">functions</a> are always implicitly valid
2358 (link-time) constants. These constants are explicitly referenced when
2359 the <a href="#identifiers">identifier for the global</a> is used and always
2360 have <a href="#t_pointer">pointer</a> type. For example, the following is a
2361 legal LLVM file:</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2362
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2363<pre class="doc_code">
Chris Lattnera18a4242007-06-06 18:28:13 +0000[diff] [blame]2364@X = global i32 17
2365@Y = global i32 42
2366@Z = global [2 x i32*] [ i32* @X, i32* @Y ]
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2367</pre>
2368
2369</div>
2370
2371<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2372<h3>
2373 <a name="undefvalues">Undefined Values</a>
2374</h3>
2375
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2376<div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2377
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2378<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]2379 indicates that the user of the value may receive an unspecified bit-pattern.
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]2380 Undefined values may be of any type (other than '<tt>label</tt>'
2381 or '<tt>void</tt>') and be used anywhere a constant is permitted.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2382
Chris Lattnerc608cb12009-09-11 01:49:31 +0000[diff] [blame]2383<p>Undefined values are useful because they indicate to the compiler that the
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2384 program is well defined no matter what value is used. This gives the
2385 compiler more freedom to optimize. Here are some examples of (potentially
2386 surprising) transformations that are valid (in pseudo IR):</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2387
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2388
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2389<pre class="doc_code">
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2390 %A = add %X, undef
2391 %B = sub %X, undef
2392 %C = xor %X, undef
2393Safe:
2394 %A = undef
2395 %B = undef
2396 %C = undef
2397</pre>
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2398
2399<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]2400 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]2401
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2402<pre class="doc_code">
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2403 %A = or %X, undef
2404 %B = and %X, undef
2405Safe:
2406 %A = -1
2407 %B = 0
2408Unsafe:
2409 %A = undef
2410 %B = undef
2411</pre>
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2412
2413<p>These logical operations have bits that are not always affected by the input.
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]2414 For example, if <tt>%X</tt> has a zero bit, then the output of the
2415 '<tt>and</tt>' operation will always be a zero for that bit, no matter what
2416 the corresponding bit from the '<tt>undef</tt>' is. As such, it is unsafe to
2417 optimize or assume that the result of the '<tt>and</tt>' is '<tt>undef</tt>'.
2418 However, it is safe to assume that all bits of the '<tt>undef</tt>' could be
2419 0, and optimize the '<tt>and</tt>' to 0. Likewise, it is safe to assume that
2420 all the bits of the '<tt>undef</tt>' operand to the '<tt>or</tt>' could be
2421 set, allowing the '<tt>or</tt>' to be folded to -1.</p>
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2422
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2423<pre class="doc_code">
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2424 %A = select undef, %X, %Y
2425 %B = select undef, 42, %Y
2426 %C = select %X, %Y, undef
2427Safe:
2428 %A = %X (or %Y)
2429 %B = 42 (or %Y)
2430 %C = %Y
2431Unsafe:
2432 %A = undef
2433 %B = undef
2434 %C = undef
2435</pre>
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2436
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]2437<p>This set of examples shows that undefined '<tt>select</tt>' (and conditional
2438 branch) conditions can go <em>either way</em>, but they have to come from one
2439 of the two operands. In the <tt>%A</tt> example, if <tt>%X</tt> and
2440 <tt>%Y</tt> were both known to have a clear low bit, then <tt>%A</tt> would
2441 have to have a cleared low bit. However, in the <tt>%C</tt> example, the
2442 optimizer is allowed to assume that the '<tt>undef</tt>' operand could be the
2443 same as <tt>%Y</tt>, allowing the whole '<tt>select</tt>' to be
2444 eliminated.</p>
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2445
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2446<pre class="doc_code">
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2447 %A = xor undef, undef
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]2448
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2449 %B = undef
2450 %C = xor %B, %B
2451
2452 %D = undef
2453 %E = icmp lt %D, 4
2454 %F = icmp gte %D, 4
2455
2456Safe:
2457 %A = undef
2458 %B = undef
2459 %C = undef
2460 %D = undef
2461 %E = undef
2462 %F = undef
2463</pre>
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2464
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]2465<p>This example points out that two '<tt>undef</tt>' operands are not
2466 necessarily the same. This can be surprising to people (and also matches C
2467 semantics) where they assume that "<tt>X^X</tt>" is always zero, even
2468 if <tt>X</tt> is undefined. This isn't true for a number of reasons, but the
2469 short answer is that an '<tt>undef</tt>' "variable" can arbitrarily change
2470 its value over its "live range". This is true because the variable doesn't
2471 actually <em>have a live range</em>. Instead, the value is logically read
2472 from arbitrary registers that happen to be around when needed, so the value
2473 is not necessarily consistent over time. In fact, <tt>%A</tt> and <tt>%C</tt>
2474 need to have the same semantics or the core LLVM "replace all uses with"
2475 concept would not hold.</p>
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2476
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2477<pre class="doc_code">
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2478 %A = fdiv undef, %X
2479 %B = fdiv %X, undef
2480Safe:
2481 %A = undef
2482b: unreachable
2483</pre>
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2484
2485<p>These examples show the crucial difference between an <em>undefined
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]2486 value</em> and <em>undefined behavior</em>. An undefined value (like
2487 '<tt>undef</tt>') is allowed to have an arbitrary bit-pattern. This means that
2488 the <tt>%A</tt> operation can be constant folded to '<tt>undef</tt>', because
2489 the '<tt>undef</tt>' could be an SNaN, and <tt>fdiv</tt> is not (currently)
2490 defined on SNaN's. However, in the second example, we can make a more
2491 aggressive assumption: because the <tt>undef</tt> is allowed to be an
2492 arbitrary value, we are allowed to assume that it could be zero. Since a
2493 divide by zero has <em>undefined behavior</em>, we are allowed to assume that
2494 the operation does not execute at all. This allows us to delete the divide and
2495 all code after it. Because the undefined operation "can't happen", the
2496 optimizer can assume that it occurs in dead code.</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]2497
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2498<pre class="doc_code">
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2499a: store undef -> %X
2500b: store %X -> undef
2501Safe:
2502a: &lt;deleted&gt;
2503b: unreachable
2504</pre>
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2505
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]2506<p>These examples reiterate the <tt>fdiv</tt> example: a store <em>of</em> an
2507 undefined value can be assumed to not have any effect; we can assume that the
2508 value is overwritten with bits that happen to match what was already there.
2509 However, a store <em>to</em> an undefined location could clobber arbitrary
2510 memory, therefore, it has undefined behavior.</p>
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2511
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2512</div>
2513
2514<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2515<h3>
Dan Gohmanbfb056d2011-12-06 03:18:47 +0000[diff] [blame]2516 <a name="poisonvalues">Poison Values</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2517</h3>
2518
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2519<div>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]2520
Dan Gohmanbfb056d2011-12-06 03:18:47 +0000[diff] [blame]2521<p>Poison values are similar to <a href="#undefvalues">undef values</a>, however
Dan Gohmane1a29842011-12-06 03:35:58 +0000[diff] [blame]2522 they also represent the fact that an instruction or constant expression which
2523 cannot evoke side effects has nevertheless detected a condition which results
2524 in undefined behavior.</p>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]2525
Dan Gohmanbfb056d2011-12-06 03:18:47 +0000[diff] [blame]2526<p>There is currently no way of representing a poison value in the IR; they
Dan Gohman855abed2010-05-03 14:51:43 +0000[diff] [blame]2527 only exist when produced by operations such as
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2528 <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]2529
Dan Gohmanbfb056d2011-12-06 03:18:47 +0000[diff] [blame]2530<p>Poison value behavior is defined in terms of value <i>dependence</i>:</p>
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2531
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2532<ul>
2533<li>Values other than <a href="#i_phi"><tt>phi</tt></a> nodes depend on
2534 their operands.</li>
2535
2536<li><a href="#i_phi"><tt>Phi</tt></a> nodes depend on the operand corresponding
2537 to their dynamic predecessor basic block.</li>
2538
2539<li>Function arguments depend on the corresponding actual argument values in
2540 the dynamic callers of their functions.</li>
2541
2542<li><a href="#i_call"><tt>Call</tt></a> instructions depend on the
2543 <a href="#i_ret"><tt>ret</tt></a> instructions that dynamically transfer
2544 control back to them.</li>
2545
Dan Gohmanb5328162010-05-03 14:55:22 +0000[diff] [blame]2546<li><a href="#i_invoke"><tt>Invoke</tt></a> instructions depend on the
Bill Wendling7b9e5392012-02-06 21:57:33 +0000[diff] [blame]2547 <a href="#i_ret"><tt>ret</tt></a>, <a href="#i_resume"><tt>resume</tt></a>,
Dan Gohmanb5328162010-05-03 14:55:22 +0000[diff] [blame]2548 or exception-throwing call instructions that dynamically transfer control
2549 back to them.</li>
2550
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2551<li>Non-volatile loads and stores depend on the most recent stores to all of the
2552 referenced memory addresses, following the order in the IR
2553 (including loads and stores implied by intrinsics such as
2554 <a href="#int_memcpy"><tt>@llvm.memcpy</tt></a>.)</li>
2555
Dan Gohman7c24ff12010-05-03 14:59:34 +0000[diff] [blame]2556<!-- TODO: In the case of multiple threads, this only applies if the store
2557 "happens-before" the load or store. -->
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2558
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2559<!-- TODO: floating-point exception state -->
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2560
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2561<li>An instruction with externally visible side effects depends on the most
2562 recent preceding instruction with externally visible side effects, following
Dan Gohmanff70fe42010-07-06 15:26:33 +0000[diff] [blame]2563 the order in the IR. (This includes
2564 <a href="#volatile">volatile operations</a>.)</li>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]2565
Dan Gohmanb5328162010-05-03 14:55:22 +0000[diff] [blame]2566<li>An instruction <i>control-depends</i> on a
2567 <a href="#terminators">terminator instruction</a>
2568 if the terminator instruction has multiple successors and the instruction
2569 is always executed when control transfers to one of the successors, and
Chris Lattner7a2bdde2011-04-15 05:18:47 +0000[diff] [blame]2570 may not be executed when control is transferred to another.</li>
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2571
Dan Gohmanca4cac42011-04-12 23:05:59 +0000[diff] [blame]2572<li>Additionally, an instruction also <i>control-depends</i> on a terminator
2573 instruction if the set of instructions it otherwise depends on would be
Chris Lattner7a2bdde2011-04-15 05:18:47 +0000[diff] [blame]2574 different if the terminator had transferred control to a different
Dan Gohmanca4cac42011-04-12 23:05:59 +0000[diff] [blame]2575 successor.</li>
2576
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2577<li>Dependence is transitive.</li>
2578
2579</ul>
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2580
Dan Gohmane1a29842011-12-06 03:35:58 +0000[diff] [blame]2581<p>Poison Values have the same behavior as <a href="#undefvalues">undef values</a>,
2582 with the additional affect that any instruction which has a <i>dependence</i>
2583 on a poison value has undefined behavior.</p>
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2584
2585<p>Here are some examples:</p>
Dan Gohmanc30f6e12010-04-26 20:54:53 +0000[diff] [blame]2586
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2587<pre class="doc_code">
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2588entry:
Dan Gohmanbfb056d2011-12-06 03:18:47 +0000[diff] [blame]2589 %poison = sub nuw i32 0, 1 ; Results in a poison value.
Dan Gohmane1a29842011-12-06 03:35:58 +0000[diff] [blame]2590 %still_poison = and i32 %poison, 0 ; 0, but also poison.
Dan Gohmanbfb056d2011-12-06 03:18:47 +0000[diff] [blame]2591 %poison_yet_again = getelementptr i32* @h, i32 %still_poison
Dan Gohmane1a29842011-12-06 03:35:58 +0000[diff] [blame]2592 store i32 0, i32* %poison_yet_again ; memory at @h[0] is poisoned
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2593
Dan Gohmane1a29842011-12-06 03:35:58 +0000[diff] [blame]2594 store i32 %poison, i32* @g ; Poison value stored to memory.
2595 %poison2 = load i32* @g ; Poison value loaded back from memory.
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2596
Dan Gohmanbfb056d2011-12-06 03:18:47 +0000[diff] [blame]2597 store volatile i32 %poison, i32* @g ; External observation; undefined behavior.
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2598
2599 %narrowaddr = bitcast i32* @g to i16*
2600 %wideaddr = bitcast i32* @g to i64*
Dan Gohmanbfb056d2011-12-06 03:18:47 +0000[diff] [blame]2601 %poison3 = load i16* %narrowaddr ; Returns a poison value.
2602 %poison4 = load i64* %wideaddr ; Returns a poison value.
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2603
Dan Gohman5cdc51e2011-12-06 03:31:14 +0000[diff] [blame]2604 %cmp = icmp slt i32 %poison, 0 ; Returns a poison value.
2605 br i1 %cmp, label %true, label %end ; Branch to either destination.
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2606
2607true:
Dan Gohman5cdc51e2011-12-06 03:31:14 +0000[diff] [blame]2608 store volatile i32 0, i32* @g ; This is control-dependent on %cmp, so
2609 ; it has undefined behavior.
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2610 br label %end
2611
2612end:
2613 %p = phi i32 [ 0, %entry ], [ 1, %true ]
Dan Gohman5cdc51e2011-12-06 03:31:14 +0000[diff] [blame]2614 ; Both edges into this PHI are
2615 ; control-dependent on %cmp, so this
2616 ; always results in a poison value.
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2617
Dan Gohman5cdc51e2011-12-06 03:31:14 +0000[diff] [blame]2618 store volatile i32 0, i32* @g ; This would depend on the store in %true
2619 ; if %cmp is true, or the store in %entry
2620 ; otherwise, so this is undefined behavior.
Dan Gohmanca4cac42011-04-12 23:05:59 +0000[diff] [blame]2621
Nick Lewycky64f9fb12011-05-16 19:29:30 +0000[diff] [blame]2622 br i1 %cmp, label %second_true, label %second_end
Dan Gohman5cdc51e2011-12-06 03:31:14 +0000[diff] [blame]2623 ; The same branch again, but this time the
2624 ; true block doesn't have side effects.
Dan Gohmanca4cac42011-04-12 23:05:59 +0000[diff] [blame]2625
2626second_true:
2627 ; No side effects!
Nick Lewycky64f9fb12011-05-16 19:29:30 +0000[diff] [blame]2628 ret void
Dan Gohmanca4cac42011-04-12 23:05:59 +0000[diff] [blame]2629
2630second_end:
Dan Gohman5cdc51e2011-12-06 03:31:14 +0000[diff] [blame]2631 store volatile i32 0, i32* @g ; This time, the instruction always depends
2632 ; on the store in %end. Also, it is
2633 ; control-equivalent to %end, so this is
Dan Gohmane1a29842011-12-06 03:35:58 +0000[diff] [blame]2634 ; well-defined (ignoring earlier undefined
2635 ; behavior in this example).
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2636</pre>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]2637
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]2638</div>
2639
2640<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2641<h3>
2642 <a name="blockaddress">Addresses of Basic Blocks</a>
2643</h3>
2644
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2645<div>
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]2646
Chris Lattnercdfc9402009-11-01 01:27:45 +0000[diff] [blame]2647<p><b><tt>blockaddress(@function, %block)</tt></b></p>
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]2648
2649<p>The '<tt>blockaddress</tt>' constant computes the address of the specified
Chris Lattner2dfdf2a2009-10-27 21:49:40 +0000[diff] [blame]2650 basic block in the specified function, and always has an i8* type. Taking
Chris Lattnercdfc9402009-11-01 01:27:45 +0000[diff] [blame]2651 the address of the entry block is illegal.</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]2652
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]2653<p>This value only has defined behavior when used as an operand to the
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]2654 '<a href="#i_indirectbr"><tt>indirectbr</tt></a>' instruction, or for
2655 comparisons against null. Pointer equality tests between labels addresses
2656 results in undefined behavior &mdash; though, again, comparison against null
2657 is ok, and no label is equal to the null pointer. This may be passed around
2658 as an opaque pointer sized value as long as the bits are not inspected. This
2659 allows <tt>ptrtoint</tt> and arithmetic to be performed on these values so
2660 long as the original value is reconstituted before the <tt>indirectbr</tt>
2661 instruction.</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]2662
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]2663<p>Finally, some targets may provide defined semantics when using the value as
2664 the operand to an inline assembly, but that is target specific.</p>
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]2665
2666</div>
2667
2668
2669<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2670<h3>
2671 <a name="constantexprs">Constant Expressions</a>
2672</h3>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2673
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2674<div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2675
2676<p>Constant expressions are used to allow expressions involving other constants
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2677 to be used as constants. Constant expressions may be of
2678 any <a href="#t_firstclass">first class</a> type and may involve any LLVM
2679 operation that does not have side effects (e.g. load and call are not
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]2680 supported). The following is the syntax for constant expressions:</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2681
2682<dl>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2683 <dt><b><tt>trunc (CST to TYPE)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2684 <dd>Truncate a constant to another type. The bit size of CST must be larger
2685 than the bit size of TYPE. Both types must be integers.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2686
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2687 <dt><b><tt>zext (CST to TYPE)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2688 <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]2689 smaller than the bit size of TYPE. Both types must be integers.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2690
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2691 <dt><b><tt>sext (CST to TYPE)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2692 <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]2693 smaller than the bit size of TYPE. Both types must be integers.</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>fptrunc (CST to TYPE)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2696 <dd>Truncate a floating point constant to another floating point type. The
2697 size of CST must be larger than the size of TYPE. Both types must be
2698 floating point.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2699
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2700 <dt><b><tt>fpext (CST to TYPE)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2701 <dd>Floating point extend a constant to another type. The size of CST must be
2702 smaller or equal to the size of TYPE. Both types must be floating
2703 point.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2704
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2705 <dt><b><tt>fptoui (CST to TYPE)</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2706 <dd>Convert a floating point constant to the corresponding unsigned integer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2707 constant. TYPE must be a scalar or vector integer type. CST must be of
2708 scalar or vector floating point type. Both CST and TYPE must be scalars,
2709 or vectors of the same number of elements. If the value won't fit in the
2710 integer type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2711
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2712 <dt><b><tt>fptosi (CST to TYPE)</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2713 <dd>Convert a floating point constant to the corresponding signed integer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2714 constant. TYPE must be a scalar or vector integer type. CST must be of
2715 scalar or vector floating point type. Both CST and TYPE must be scalars,
2716 or vectors of the same number of elements. If the value won't fit in the
2717 integer type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2718
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2719 <dt><b><tt>uitofp (CST to TYPE)</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2720 <dd>Convert an unsigned integer constant to the corresponding floating point
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2721 constant. TYPE must be a scalar or vector floating point type. CST must be
2722 of scalar or vector integer type. Both CST and TYPE must be scalars, or
2723 vectors of the same number of elements. If the value won't fit in the
2724 floating point type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2725
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2726 <dt><b><tt>sitofp (CST to TYPE)</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2727 <dd>Convert a signed integer constant to the corresponding floating point
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2728 constant. TYPE must be a scalar or vector floating point type. CST must be
2729 of scalar or vector integer type. Both CST and TYPE must be scalars, or
2730 vectors of the same number of elements. If the value won't fit in the
2731 floating point type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2732
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2733 <dt><b><tt>ptrtoint (CST to TYPE)</tt></b></dt>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]2734 <dd>Convert a pointer typed constant to the corresponding integer constant
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2735 <tt>TYPE</tt> must be an integer type. <tt>CST</tt> must be of pointer
2736 type. The <tt>CST</tt> value is zero extended, truncated, or unchanged to
2737 make it fit in <tt>TYPE</tt>.</dd>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]2738
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2739 <dt><b><tt>inttoptr (CST to TYPE)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2740 <dd>Convert a integer constant to a pointer constant. TYPE must be a pointer
2741 type. CST must be of integer type. The CST value is zero extended,
2742 truncated, or unchanged to make it fit in a pointer size. This one is
2743 <i>really</i> dangerous!</dd>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]2744
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2745 <dt><b><tt>bitcast (CST to TYPE)</tt></b></dt>
Chris Lattner03bbad62009-02-28 18:27:03 +0000[diff] [blame]2746 <dd>Convert a constant, CST, to another TYPE. The constraints of the operands
2747 are the same as those for the <a href="#i_bitcast">bitcast
2748 instruction</a>.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2749
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2750 <dt><b><tt>getelementptr (CSTPTR, IDX0, IDX1, ...)</tt></b></dt>
2751 <dt><b><tt>getelementptr inbounds (CSTPTR, IDX0, IDX1, ...)</tt></b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2752 <dd>Perform the <a href="#i_getelementptr">getelementptr operation</a> on
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2753 constants. As with the <a href="#i_getelementptr">getelementptr</a>
2754 instruction, the index list may have zero or more indexes, which are
2755 required to make sense for the type of "CSTPTR".</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2756
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2757 <dt><b><tt>select (COND, VAL1, VAL2)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2758 <dd>Perform the <a href="#i_select">select operation</a> on constants.</dd>
Reid Spencer01c42592006-12-04 19:23:19 +0000[diff] [blame]2759
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2760 <dt><b><tt>icmp COND (VAL1, VAL2)</tt></b></dt>
Reid Spencer01c42592006-12-04 19:23:19 +0000[diff] [blame]2761 <dd>Performs the <a href="#i_icmp">icmp operation</a> on constants.</dd>
2762
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2763 <dt><b><tt>fcmp COND (VAL1, VAL2)</tt></b></dt>
Reid Spencer01c42592006-12-04 19:23:19 +0000[diff] [blame]2764 <dd>Performs the <a href="#i_fcmp">fcmp operation</a> on constants.</dd>
Robert Bocchino9fbe1452006-01-10 19:31:34 +0000[diff] [blame]2765
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2766 <dt><b><tt>extractelement (VAL, IDX)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2767 <dd>Perform the <a href="#i_extractelement">extractelement operation</a> on
2768 constants.</dd>
Robert Bocchino9fbe1452006-01-10 19:31:34 +0000[diff] [blame]2769
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2770 <dt><b><tt>insertelement (VAL, ELT, IDX)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2771 <dd>Perform the <a href="#i_insertelement">insertelement operation</a> on
2772 constants.</dd>
Chris Lattnerc1989542006-04-08 00:13:41 +0000[diff] [blame]2773
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2774 <dt><b><tt>shufflevector (VEC1, VEC2, IDXMASK)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2775 <dd>Perform the <a href="#i_shufflevector">shufflevector operation</a> on
2776 constants.</dd>
Chris Lattnerc1989542006-04-08 00:13:41 +0000[diff] [blame]2777
Nick Lewycky9e130ce2010-05-29 06:44:15 +0000[diff] [blame]2778 <dt><b><tt>extractvalue (VAL, IDX0, IDX1, ...)</tt></b></dt>
2779 <dd>Perform the <a href="#i_extractvalue">extractvalue operation</a> on
2780 constants. The index list is interpreted in a similar manner as indices in
2781 a '<a href="#i_getelementptr">getelementptr</a>' operation. At least one
2782 index value must be specified.</dd>
2783
2784 <dt><b><tt>insertvalue (VAL, ELT, IDX0, IDX1, ...)</tt></b></dt>
2785 <dd>Perform the <a href="#i_insertvalue">insertvalue operation</a> on
2786 constants. The index list is interpreted in a similar manner as indices in
2787 a '<a href="#i_getelementptr">getelementptr</a>' operation. At least one
2788 index value must be specified.</dd>
2789
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2790 <dt><b><tt>OPCODE (LHS, RHS)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2791 <dd>Perform the specified operation of the LHS and RHS constants. OPCODE may
2792 be any of the <a href="#binaryops">binary</a>
2793 or <a href="#bitwiseops">bitwise binary</a> operations. The constraints
2794 on operands are the same as those for the corresponding instruction
2795 (e.g. no bitwise operations on floating point values are allowed).</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2796</dl>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2797
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2798</div>
Chris Lattner9ee5d222004-03-08 16:49:10 +0000[diff] [blame]2799
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2800</div>
2801
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2802<!-- *********************************************************************** -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2803<h2><a name="othervalues">Other Values</a></h2>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2804<!-- *********************************************************************** -->
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2805<div>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2806<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2807<h3>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2808<a name="inlineasm">Inline Assembler Expressions</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2809</h3>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2810
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2811<div>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2812
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2813<p>LLVM supports inline assembler expressions (as opposed
Bill Wendlingaee0f452011-11-30 21:52:43 +0000[diff] [blame]2814 to <a href="#moduleasm">Module-Level Inline Assembly</a>) through the use of
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2815 a special value. This value represents the inline assembler as a string
2816 (containing the instructions to emit), a list of operand constraints (stored
Dale Johannesen09fed252009-10-13 21:56:55 +0000[diff] [blame]2817 as a string), a flag that indicates whether or not the inline asm
Dale Johannesen8ba2d5b2009-10-21 23:28:00 +0000[diff] [blame]2818 expression has side effects, and a flag indicating whether the function
2819 containing the asm needs to align its stack conservatively. An example
2820 inline assembler expression is:</p>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2821
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2822<pre class="doc_code">
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2823i32 (i32) asm "bswap $0", "=r,r"
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2824</pre>
2825
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2826<p>Inline assembler expressions may <b>only</b> be used as the callee operand of
2827 a <a href="#i_call"><tt>call</tt> instruction</a>. Thus, typically we
2828 have:</p>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2829
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2830<pre class="doc_code">
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2831%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]2832</pre>
2833
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2834<p>Inline asms with side effects not visible in the constraint list must be
2835 marked as having side effects. This is done through the use of the
2836 '<tt>sideeffect</tt>' keyword, like so:</p>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2837
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2838<pre class="doc_code">
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2839call void asm sideeffect "eieio", ""()
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2840</pre>
2841
Dale Johannesen8ba2d5b2009-10-21 23:28:00 +0000[diff] [blame]2842<p>In some cases inline asms will contain code that will not work unless the
2843 stack is aligned in some way, such as calls or SSE instructions on x86,
2844 yet will not contain code that does that alignment within the asm.
2845 The compiler should make conservative assumptions about what the asm might
2846 contain and should generate its usual stack alignment code in the prologue
2847 if the '<tt>alignstack</tt>' keyword is present:</p>
Dale Johannesen09fed252009-10-13 21:56:55 +0000[diff] [blame]2848
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2849<pre class="doc_code">
Dale Johannesen8ba2d5b2009-10-21 23:28:00 +0000[diff] [blame]2850call void asm alignstack "eieio", ""()
Dale Johannesen09fed252009-10-13 21:56:55 +0000[diff] [blame]2851</pre>
Dale Johannesen09fed252009-10-13 21:56:55 +0000[diff] [blame]2852
2853<p>If both keywords appear the '<tt>sideeffect</tt>' keyword must come
2854 first.</p>
2855
Bill Wendlingaee0f452011-11-30 21:52:43 +0000[diff] [blame]2856<!--
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2857<p>TODO: The format of the asm and constraints string still need to be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2858 documented here. Constraints on what can be done (e.g. duplication, moving,
2859 etc need to be documented). This is probably best done by reference to
2860 another document that covers inline asm from a holistic perspective.</p>
Bill Wendlingaee0f452011-11-30 21:52:43 +0000[diff] [blame]2861 -->
Chris Lattnercf9a4152010-04-07 05:38:05 +0000[diff] [blame]2862
Bill Wendlingaee0f452011-11-30 21:52:43 +0000[diff] [blame]2863<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2864<h4>
Bill Wendlingaee0f452011-11-30 21:52:43 +0000[diff] [blame]2865 <a name="inlineasm_md">Inline Asm Metadata</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2866</h4>
Chris Lattnercf9a4152010-04-07 05:38:05 +0000[diff] [blame]2867
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2868<div>
Chris Lattnercf9a4152010-04-07 05:38:05 +0000[diff] [blame]2869
Bill Wendlingaee0f452011-11-30 21:52:43 +0000[diff] [blame]2870<p>The call instructions that wrap inline asm nodes may have a
2871 "<tt>!srcloc</tt>" MDNode attached to it that contains a list of constant
2872 integers. If present, the code generator will use the integer as the
2873 location cookie value when report errors through the <tt>LLVMContext</tt>
2874 error reporting mechanisms. This allows a front-end to correlate backend
2875 errors that occur with inline asm back to the source code that produced it.
2876 For example:</p>
Chris Lattnercf9a4152010-04-07 05:38:05 +0000[diff] [blame]2877
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2878<pre class="doc_code">
Chris Lattnercf9a4152010-04-07 05:38:05 +0000[diff] [blame]2879call void asm sideeffect "something bad", ""()<b>, !srcloc !42</b>
2880...
2881!42 = !{ i32 1234567 }
2882</pre>
Chris Lattnercf9a4152010-04-07 05:38:05 +0000[diff] [blame]2883
2884<p>It is up to the front-end to make sense of the magic numbers it places in the
Bill Wendlingaee0f452011-11-30 21:52:43 +0000[diff] [blame]2885 IR. If the MDNode contains multiple constants, the code generator will use
Chris Lattnerce1b9ad2010-11-17 08:20:42 +0000[diff] [blame]2886 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]2887
2888</div>
2889
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2890</div>
2891
Chris Lattnere6a5ddd2010-01-15 21:50:19 +0000[diff] [blame]2892<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2893<h3>
2894 <a name="metadata">Metadata Nodes and Metadata Strings</a>
2895</h3>
Chris Lattnere6a5ddd2010-01-15 21:50:19 +0000[diff] [blame]2896
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2897<div>
Chris Lattnere6a5ddd2010-01-15 21:50:19 +0000[diff] [blame]2898
2899<p>LLVM IR allows metadata to be attached to instructions in the program that
2900 can convey extra information about the code to the optimizers and code
2901 generator. One example application of metadata is source-level debug
2902 information. There are two metadata primitives: strings and nodes. All
2903 metadata has the <tt>metadata</tt> type and is identified in syntax by a
2904 preceding exclamation point ('<tt>!</tt>').</p>
2905
2906<p>A metadata string is a string surrounded by double quotes. It can contain
Bill Wendlingf6cc4c22011-11-30 21:43:43 +0000[diff] [blame]2907 any character by escaping non-printable characters with "<tt>\xx</tt>" where
2908 "<tt>xx</tt>" is the two digit hex code. For example:
2909 "<tt>!"test\00"</tt>".</p>
Chris Lattnere6a5ddd2010-01-15 21:50:19 +0000[diff] [blame]2910
2911<p>Metadata nodes are represented with notation similar to structure constants
2912 (a comma separated list of elements, surrounded by braces and preceded by an
Bill Wendlingf6cc4c22011-11-30 21:43:43 +0000[diff] [blame]2913 exclamation point). Metadata nodes can have any values as their operand. For
2914 example:</p>
2915
2916<div class="doc_code">
2917<pre>
2918!{ metadata !"test\00", i32 10}
2919</pre>
2920</div>
Chris Lattnere6a5ddd2010-01-15 21:50:19 +0000[diff] [blame]2921
2922<p>A <a href="#namedmetadatastructure">named metadata</a> is a collection of
2923 metadata nodes, which can be looked up in the module symbol table. For
Bill Wendlingf6cc4c22011-11-30 21:43:43 +0000[diff] [blame]2924 example:</p>
2925
2926<div class="doc_code">
2927<pre>
2928!foo = metadata !{!4, !3}
2929</pre>
2930</div>
Chris Lattnere6a5ddd2010-01-15 21:50:19 +0000[diff] [blame]2931
Devang Patele1d50cd2010-03-04 23:44:48 +0000[diff] [blame]2932<p>Metadata can be used as function arguments. Here <tt>llvm.dbg.value</tt>
Bill Wendlingf6cc4c22011-11-30 21:43:43 +0000[diff] [blame]2933 function is using two metadata arguments:</p>
Devang Patele1d50cd2010-03-04 23:44:48 +0000[diff] [blame]2934
Bill Wendling9ff5de92011-03-02 02:17:11 +0000[diff] [blame]2935<div class="doc_code">
2936<pre>
2937call void @llvm.dbg.value(metadata !24, i64 0, metadata !25)
2938</pre>
2939</div>
Devang Patele1d50cd2010-03-04 23:44:48 +0000[diff] [blame]2940
2941<p>Metadata can be attached with an instruction. Here metadata <tt>!21</tt> is
Bill Wendlingf6cc4c22011-11-30 21:43:43 +0000[diff] [blame]2942 attached to the <tt>add</tt> instruction using the <tt>!dbg</tt>
2943 identifier:</p>
Devang Patele1d50cd2010-03-04 23:44:48 +0000[diff] [blame]2944
Bill Wendling9ff5de92011-03-02 02:17:11 +0000[diff] [blame]2945<div class="doc_code">
2946<pre>
2947%indvar.next = add i64 %indvar, 1, !dbg !21
2948</pre>
2949</div>
2950
Peter Collingbourne249d9532011-10-27 19:19:07 +0000[diff] [blame]2951<p>More information about specific metadata nodes recognized by the optimizers
2952 and code generator is found below.</p>
2953
Bill Wendlingf6cc4c22011-11-30 21:43:43 +0000[diff] [blame]2954<!-- _______________________________________________________________________ -->
Peter Collingbourne249d9532011-10-27 19:19:07 +0000[diff] [blame]2955<h4>
2956 <a name="tbaa">'<tt>tbaa</tt>' Metadata</a>
2957</h4>
2958
2959<div>
2960
2961<p>In LLVM IR, memory does not have types, so LLVM's own type system is not
2962 suitable for doing TBAA. Instead, metadata is added to the IR to describe
2963 a type system of a higher level language. This can be used to implement
2964 typical C/C++ TBAA, but it can also be used to implement custom alias
2965 analysis behavior for other languages.</p>
2966
2967<p>The current metadata format is very simple. TBAA metadata nodes have up to
2968 three fields, e.g.:</p>
2969
2970<div class="doc_code">
2971<pre>
2972!0 = metadata !{ metadata !"an example type tree" }
2973!1 = metadata !{ metadata !"int", metadata !0 }
2974!2 = metadata !{ metadata !"float", metadata !0 }
2975!3 = metadata !{ metadata !"const float", metadata !2, i64 1 }
2976</pre>
2977</div>
2978
2979<p>The first field is an identity field. It can be any value, usually
2980 a metadata string, which uniquely identifies the type. The most important
2981 name in the tree is the name of the root node. Two trees with
2982 different root node names are entirely disjoint, even if they
2983 have leaves with common names.</p>
2984
2985<p>The second field identifies the type's parent node in the tree, or
2986 is null or omitted for a root node. A type is considered to alias
2987 all of its descendants and all of its ancestors in the tree. Also,
2988 a type is considered to alias all types in other trees, so that
2989 bitcode produced from multiple front-ends is handled conservatively.</p>
2990
2991<p>If the third field is present, it's an integer which if equal to 1
2992 indicates that the type is "constant" (meaning
2993 <tt>pointsToConstantMemory</tt> should return true; see
2994 <a href="AliasAnalysis.html#OtherItfs">other useful
2995 <tt>AliasAnalysis</tt> methods</a>).</p>
2996
2997</div>
2998
Bill Wendlingf6cc4c22011-11-30 21:43:43 +0000[diff] [blame]2999<!-- _______________________________________________________________________ -->
Peter Collingbourne999f90b2011-10-27 19:19:14 +0000[diff] [blame]3000<h4>
3001 <a name="fpaccuracy">'<tt>fpaccuracy</tt>' Metadata</a>
3002</h4>
3003
3004<div>
3005
3006<p><tt>fpaccuracy</tt> metadata may be attached to any instruction of floating
3007 point type. It expresses the maximum relative error of the result of
3008 that instruction, in ULPs. ULP is defined as follows:</p>
3009
Bill Wendling0656e252011-11-09 19:33:56 +0000[diff] [blame]3010<blockquote>
3011
3012<p>If <tt>x</tt> is a real number that lies between two finite consecutive
3013 floating-point numbers <tt>a</tt> and <tt>b</tt>, without being equal to one
3014 of them, then <tt>ulp(x) = |b - a|</tt>, otherwise <tt>ulp(x)</tt> is the
3015 distance between the two non-equal finite floating-point numbers nearest
3016 <tt>x</tt>. Moreover, <tt>ulp(NaN)</tt> is <tt>NaN</tt>.</p>
3017
3018</blockquote>
Peter Collingbourne999f90b2011-10-27 19:19:14 +0000[diff] [blame]3019
3020<p>The maximum relative error may be any rational number. The metadata node
3021 shall consist of a pair of unsigned integers respectively representing
3022 the numerator and denominator. For example, 2.5 ULP:</p>
3023
3024<div class="doc_code">
3025<pre>
3026!0 = metadata !{ i32 5, i32 2 }
3027</pre>
3028</div>
3029
3030</div>
3031
Chris Lattnere6a5ddd2010-01-15 21:50:19 +0000[diff] [blame]3032</div>
3033
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3034</div>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3035
3036<!-- *********************************************************************** -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3037<h2>
Bill Wendlingb9d75a92012-02-11 11:59:36 +0000[diff] [blame]3038 <a name="module_flags">Module Flags Metadata</a>
3039</h2>
3040<!-- *********************************************************************** -->
3041
3042<div>
3043
3044<p>Information about the module as a whole is difficult to convey to LLVM's
3045 subsystems. The LLVM IR isn't sufficient to transmit this
3046 information. The <tt>llvm.module.flags</tt> named metadata exists in order to
3047 facilitate this. These flags are in the form of key / value pairs &mdash;
3048 much like a dictionary &mdash; making it easy for any subsystem who cares
3049 about a flag to look it up.</p>
3050
3051<p>The <tt>llvm.module.flags</tt> metadata contains a list of metadata
3052 triplets. Each triplet has the following form:</p>
3053
3054<ul>
3055 <li>The first element is a <i>behavior</i> flag, which specifies the behavior
3056 when two (or more) modules are merged together, and it encounters two (or
3057 more) metadata with the same ID. The supported behaviors are described
3058 below.</li>
3059
3060 <li>The second element is a metadata string that is a unique ID for the
3061 metadata. How each ID is interpreted is documented below.</li>
3062
3063 <li>The third element is the value of the flag.</li>
3064</ul>
3065
3066<p>When two (or more) modules are merged together, the resulting
3067 <tt>llvm.module.flags</tt> metadata is the union of the
3068 modules' <tt>llvm.module.flags</tt> metadata. The only exception being a flag
3069 with the <i>Override</i> behavior, which may override another flag's value
3070 (see below).</p>
3071
3072<p>The following behaviors are supported:</p>
3073
3074<table border="1" cellspacing="0" cellpadding="4">
3075 <tbody>
3076 <tr>
3077 <th>Value</th>
3078 <th>Behavior</th>
3079 </tr>
3080 <tr>
3081 <td>1</td>
3082 <td align="left">
3083 <dt><b>Error</b></dt>
3084 <dd>Emits an error if two values disagree. It is an error to have an ID
3085 with both an Error and a Warning behavior.</dd>
3086 </td>
3087 </tr>
3088 <tr>
3089 <td>2</td>
3090 <td align="left">
3091 <dt><b>Warning</b></dt>
3092 <dd>Emits a warning if two values disagree.</dd>
3093 </td>
3094 </tr>
3095 <tr>
3096 <td>3</td>
3097 <td align="left">
3098 <dt><b>Require</b></dt>
3099 <dd>Emits an error when the specified value is not present or doesn't
3100 have the specified value. It is an error for two (or more)
3101 <tt>llvm.module.flags</tt> with the same ID to have the Require
3102 behavior but different values. There may be multiple Require flags
3103 per ID.</dd>
3104 </td>
3105 </tr>
3106 <tr>
3107 <td>4</td>
3108 <td align="left">
3109 <dt><b>Override</b></dt>
3110 <dd>Uses the specified value if the two values disagree. It is an error
3111 for two (or more) <tt>llvm.module.flags</tt> with the same ID to
3112 have the Override behavior but different values.</dd>
3113 </td>
3114 </tr>
3115 </tbody>
3116</table>
3117
3118<p>An example of module flags:</p>
3119
3120<pre class="doc_code">
3121!0 = metadata !{ i32 1, metadata !"foo", i32 1 }
3122!1 = metadata !{ i32 4, metadata !"bar", i32 37 }
3123!2 = metadata !{ i32 2, metadata !"qux", i32 42 }
3124!3 = metadata !{ i32 3, metadata !"qux",
3125 metadata !{
3126 metadata !"foo", i32 1
3127 }
3128}
3129!llvm.module.flags = !{ !0, !1, !2, !3 }
3130</pre>
3131
3132<ul>
3133 <li><p>Metadata <tt>!0</tt> has the ID <tt>!"foo"</tt> and the value '1'. The
3134 behavior if two or more <tt>!"foo"</tt> flags are seen is to emit an
3135 error if their values are not equal.</p></li>
3136
3137 <li><p>Metadata <tt>!1</tt> has the ID <tt>!"bar"</tt> and the value '37'. The
3138 behavior if two or more <tt>!"bar"</tt> flags are seen is to use the
3139 value '37' if their values are not equal.</p></li>
3140
3141 <li><p>Metadata <tt>!2</tt> has the ID <tt>!"qux"</tt> and the value '42'. The
3142 behavior if two or more <tt>!"qux"</tt> flags are seen is to emit a
3143 warning if their values are not equal.</p></li>
3144
3145 <li><p>Metadata <tt>!3</tt> has the ID <tt>!"qux"</tt> and the value:</p>
3146
3147<pre class="doc_code">
3148metadata !{ metadata !"foo", i32 1 }
3149</pre>
3150 <p>The behavior is to emit an error if the <tt>llvm.module.flags</tt> does
3151 not contain a flag with the ID <tt>!"foo"</tt> that has the value
3152 '1'. If two or more <tt>!"qux"</tt> flags exist, then they must have
3153 the same value or an error will be issued.</p></li>
3154</ul>
3155
3156</div>
3157
3158<!-- *********************************************************************** -->
3159<h2>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3160 <a name="intrinsic_globals">Intrinsic Global Variables</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3161</h2>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3162<!-- *********************************************************************** -->
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3163<div>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3164<p>LLVM has a number of "magic" global variables that contain data that affect
3165code generation or other IR semantics. These are documented here. All globals
Chris Lattner401e10c2009-07-20 06:14:25 +0000[diff] [blame]3166of this sort should have a section specified as "<tt>llvm.metadata</tt>". This
3167section and all globals that start with "<tt>llvm.</tt>" are reserved for use
3168by LLVM.</p>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3169
3170<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3171<h3>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3172<a name="intg_used">The '<tt>llvm.used</tt>' Global Variable</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3173</h3>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3174
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3175<div>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3176
3177<p>The <tt>@llvm.used</tt> global is an array with i8* element type which has <a
3178href="#linkage_appending">appending linkage</a>. This array contains a list of
3179pointers to global variables and functions which may optionally have a pointer
3180cast formed of bitcast or getelementptr. For example, a legal use of it is:</p>
3181
Bill Wendling9ae75632011-11-08 00:32:45 +0000[diff] [blame]3182<div class="doc_code">
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3183<pre>
Bill Wendling9ae75632011-11-08 00:32:45 +0000[diff] [blame]3184@X = global i8 4
3185@Y = global i32 123
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3186
Bill Wendling9ae75632011-11-08 00:32:45 +0000[diff] [blame]3187@llvm.used = appending global [2 x i8*] [
3188 i8* @X,
3189 i8* bitcast (i32* @Y to i8*)
3190], section "llvm.metadata"
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3191</pre>
Bill Wendling9ae75632011-11-08 00:32:45 +0000[diff] [blame]3192</div>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3193
3194<p>If a global variable appears in the <tt>@llvm.used</tt> list, then the
Bill Wendling9ae75632011-11-08 00:32:45 +0000[diff] [blame]3195 compiler, assembler, and linker are required to treat the symbol as if there
3196 is a reference to the global that it cannot see. For example, if a variable
3197 has internal linkage and no references other than that from
3198 the <tt>@llvm.used</tt> list, it cannot be deleted. This is commonly used to
3199 represent references from inline asms and other things the compiler cannot
3200 "see", and corresponds to "<tt>attribute((used))</tt>" in GNU C.</p>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3201
3202<p>On some targets, the code generator must emit a directive to the assembler or
Bill Wendling9ae75632011-11-08 00:32:45 +0000[diff] [blame]3203 object file to prevent the assembler and linker from molesting the
3204 symbol.</p>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3205
3206</div>
3207
3208<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3209<h3>
3210 <a name="intg_compiler_used">
3211 The '<tt>llvm.compiler.used</tt>' Global Variable
3212 </a>
3213</h3>
Chris Lattner401e10c2009-07-20 06:14:25 +0000[diff] [blame]3214
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3215<div>
Chris Lattner401e10c2009-07-20 06:14:25 +0000[diff] [blame]3216
3217<p>The <tt>@llvm.compiler.used</tt> directive is the same as the
Bill Wendling9ae75632011-11-08 00:32:45 +0000[diff] [blame]3218 <tt>@llvm.used</tt> directive, except that it only prevents the compiler from
3219 touching the symbol. On targets that support it, this allows an intelligent
3220 linker to optimize references to the symbol without being impeded as it would
3221 be by <tt>@llvm.used</tt>.</p>
Chris Lattner401e10c2009-07-20 06:14:25 +0000[diff] [blame]3222
3223<p>This is a rare construct that should only be used in rare circumstances, and
Bill Wendling9ae75632011-11-08 00:32:45 +0000[diff] [blame]3224 should not be exposed to source languages.</p>
Chris Lattner401e10c2009-07-20 06:14:25 +0000[diff] [blame]3225
3226</div>
3227
3228<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3229<h3>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3230<a name="intg_global_ctors">The '<tt>llvm.global_ctors</tt>' Global Variable</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3231</h3>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3232
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3233<div>
Bill Wendling9ae75632011-11-08 00:32:45 +0000[diff] [blame]3234
3235<div class="doc_code">
David Chisnalle31e9962010-04-30 19:23:49 +0000[diff] [blame]3236<pre>
3237%0 = type { i32, void ()* }
David Chisnall27195a52010-04-30 19:27:35 +0000[diff] [blame]3238@llvm.global_ctors = appending global [1 x %0] [%0 { i32 65535, void ()* @ctor }]
David Chisnalle31e9962010-04-30 19:23:49 +0000[diff] [blame]3239</pre>
Bill Wendling9ae75632011-11-08 00:32:45 +0000[diff] [blame]3240</div>
3241
3242<p>The <tt>@llvm.global_ctors</tt> array contains a list of constructor
3243 functions and associated priorities. The functions referenced by this array
3244 will be called in ascending order of priority (i.e. lowest first) when the
3245 module is loaded. The order of functions with the same priority is not
3246 defined.</p>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3247
3248</div>
3249
3250<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3251<h3>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3252<a name="intg_global_dtors">The '<tt>llvm.global_dtors</tt>' Global Variable</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3253</h3>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3254
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3255<div>
Bill Wendling9ae75632011-11-08 00:32:45 +0000[diff] [blame]3256
3257<div class="doc_code">
David Chisnalle31e9962010-04-30 19:23:49 +0000[diff] [blame]3258<pre>
3259%0 = type { i32, void ()* }
David Chisnall27195a52010-04-30 19:27:35 +0000[diff] [blame]3260@llvm.global_dtors = appending global [1 x %0] [%0 { i32 65535, void ()* @dtor }]
David Chisnalle31e9962010-04-30 19:23:49 +0000[diff] [blame]3261</pre>
Bill Wendling9ae75632011-11-08 00:32:45 +0000[diff] [blame]3262</div>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3263
Bill Wendling9ae75632011-11-08 00:32:45 +0000[diff] [blame]3264<p>The <tt>@llvm.global_dtors</tt> array contains a list of destructor functions
3265 and associated priorities. The functions referenced by this array will be
3266 called in descending order of priority (i.e. highest first) when the module
3267 is loaded. The order of functions with the same priority is not defined.</p>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3268
3269</div>
3270
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3271</div>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3272
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]3273<!-- *********************************************************************** -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3274<h2><a name="instref">Instruction Reference</a></h2>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3275<!-- *********************************************************************** -->
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]3276
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3277<div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]3278
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3279<p>The LLVM instruction set consists of several different classifications of
3280 instructions: <a href="#terminators">terminator
3281 instructions</a>, <a href="#binaryops">binary instructions</a>,
3282 <a href="#bitwiseops">bitwise binary instructions</a>,
3283 <a href="#memoryops">memory instructions</a>, and
3284 <a href="#otherops">other instructions</a>.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]3285
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3286<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3287<h3>
3288 <a name="terminators">Terminator Instructions</a>
3289</h3>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]3290
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3291<div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]3292
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3293<p>As mentioned <a href="#functionstructure">previously</a>, every basic block
3294 in a program ends with a "Terminator" instruction, which indicates which
3295 block should be executed after the current block is finished. These
3296 terminator instructions typically yield a '<tt>void</tt>' value: they produce
3297 control flow, not values (the one exception being the
3298 '<a href="#i_invoke"><tt>invoke</tt></a>' instruction).</p>
3299
Chris Lattner6445ecb2011-08-02 20:29:13 +0000[diff] [blame]3300<p>The terminator instructions are:
3301 '<a href="#i_ret"><tt>ret</tt></a>',
3302 '<a href="#i_br"><tt>br</tt></a>',
3303 '<a href="#i_switch"><tt>switch</tt></a>',
3304 '<a href="#i_indirectbr"><tt>indirectbr</tt></a>',
3305 '<a href="#i_invoke"><tt>invoke</tt></a>',
Chris Lattner6445ecb2011-08-02 20:29:13 +0000[diff] [blame]3306 '<a href="#i_resume"><tt>resume</tt></a>', and
3307 '<a href="#i_unreachable"><tt>unreachable</tt></a>'.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]3308
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3309<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3310<h4>
3311 <a name="i_ret">'<tt>ret</tt>' Instruction</a>
3312</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3313
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3314<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3315
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3316<h5>Syntax:</h5>
Dan Gohmanb1e6b962008-10-04 19:00:07 +0000[diff] [blame]3317<pre>
3318 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]3319 ret void <i>; Return from void function</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3320</pre>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]3321
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3322<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3323<p>The '<tt>ret</tt>' instruction is used to return control flow (and optionally
3324 a value) from a function back to the caller.</p>
3325
3326<p>There are two forms of the '<tt>ret</tt>' instruction: one that returns a
3327 value and then causes control flow, and one that just causes control flow to
3328 occur.</p>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]3329
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3330<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3331<p>The '<tt>ret</tt>' instruction optionally accepts a single argument, the
3332 return value. The type of the return value must be a
3333 '<a href="#t_firstclass">first class</a>' type.</p>
Dan Gohmanb1e6b962008-10-04 19:00:07 +0000[diff] [blame]3334
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3335<p>A function is not <a href="#wellformed">well formed</a> if it it has a
3336 non-void return type and contains a '<tt>ret</tt>' instruction with no return
3337 value or a return value with a type that does not match its type, or if it
3338 has a void return type and contains a '<tt>ret</tt>' instruction with a
3339 return value.</p>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]3340
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3341<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3342<p>When the '<tt>ret</tt>' instruction is executed, control flow returns back to
3343 the calling function's context. If the caller is a
3344 "<a href="#i_call"><tt>call</tt></a>" instruction, execution continues at the
3345 instruction after the call. If the caller was an
3346 "<a href="#i_invoke"><tt>invoke</tt></a>" instruction, execution continues at
3347 the beginning of the "normal" destination block. If the instruction returns
3348 a value, that value shall set the call or invoke instruction's return
3349 value.</p>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]3350
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3351<h5>Example:</h5>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]3352<pre>
3353 ret i32 5 <i>; Return an integer value of 5</i>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]3354 ret void <i>; Return from a void function</i>
Bill Wendling0a4bbbf2009-02-28 22:12:54 +0000[diff] [blame]3355 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]3356</pre>
Dan Gohmanf3e60bd2009-01-12 23:12:39 +0000[diff] [blame]3357
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3358</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3359<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3360<h4>
3361 <a name="i_br">'<tt>br</tt>' Instruction</a>
3362</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3363
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3364<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3365
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3366<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3367<pre>
Bill Wendlingb3aa4712011-07-26 10:41:15 +0000[diff] [blame]3368 br i1 &lt;cond&gt;, label &lt;iftrue&gt;, label &lt;iffalse&gt;
3369 br label &lt;dest&gt; <i>; Unconditional branch</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3370</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3371
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3372<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3373<p>The '<tt>br</tt>' instruction is used to cause control flow to transfer to a
3374 different basic block in the current function. There are two forms of this
3375 instruction, corresponding to a conditional branch and an unconditional
3376 branch.</p>
3377
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3378<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3379<p>The conditional branch form of the '<tt>br</tt>' instruction takes a single
3380 '<tt>i1</tt>' value and two '<tt>label</tt>' values. The unconditional form
3381 of the '<tt>br</tt>' instruction takes a single '<tt>label</tt>' value as a
3382 target.</p>
3383
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3384<h5>Semantics:</h5>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3385<p>Upon execution of a conditional '<tt>br</tt>' instruction, the '<tt>i1</tt>'
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3386 argument is evaluated. If the value is <tt>true</tt>, control flows to the
3387 '<tt>iftrue</tt>' <tt>label</tt> argument. If "cond" is <tt>false</tt>,
3388 control flows to the '<tt>iffalse</tt>' <tt>label</tt> argument.</p>
3389
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3390<h5>Example:</h5>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]3391<pre>
3392Test:
3393 %cond = <a href="#i_icmp">icmp</a> eq i32 %a, %b
3394 br i1 %cond, label %IfEqual, label %IfUnequal
3395IfEqual:
3396 <a href="#i_ret">ret</a> i32 1
3397IfUnequal:
3398 <a href="#i_ret">ret</a> i32 0
3399</pre>
3400
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3401</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3402
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3403<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3404<h4>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3405 <a name="i_switch">'<tt>switch</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3406</h4>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3407
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3408<div>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3409
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3410<h5>Syntax:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3411<pre>
3412 switch &lt;intty&gt; &lt;value&gt;, label &lt;defaultdest&gt; [ &lt;intty&gt; &lt;val&gt;, label &lt;dest&gt; ... ]
3413</pre>
3414
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3415<h5>Overview:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3416<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]3417 several different places. It is a generalization of the '<tt>br</tt>'
3418 instruction, allowing a branch to occur to one of many possible
3419 destinations.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3420
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3421<h5>Arguments:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3422<p>The '<tt>switch</tt>' instruction uses three parameters: an integer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3423 comparison value '<tt>value</tt>', a default '<tt>label</tt>' destination,
3424 and an array of pairs of comparison value constants and '<tt>label</tt>'s.
3425 The table is not allowed to contain duplicate constant entries.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3426
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3427<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3428<p>The <tt>switch</tt> instruction specifies a table of values and
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3429 destinations. When the '<tt>switch</tt>' instruction is executed, this table
3430 is searched for the given value. If the value is found, control flow is
Benjamin Kramer8040cd32009-10-12 14:46:08 +0000[diff] [blame]3431 transferred to the corresponding destination; otherwise, control flow is
3432 transferred to the default destination.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3433
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3434<h5>Implementation:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3435<p>Depending on properties of the target machine and the particular
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3436 <tt>switch</tt> instruction, this instruction may be code generated in
3437 different ways. For example, it could be generated as a series of chained
3438 conditional branches or with a lookup table.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3439
3440<h5>Example:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3441<pre>
3442 <i>; Emulate a conditional br instruction</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3443 %Val = <a href="#i_zext">zext</a> i1 %value to i32
Dan Gohman2a08c532009-01-04 23:44:43 +0000[diff] [blame]3444 switch i32 %Val, label %truedest [ i32 0, label %falsedest ]
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3445
3446 <i>; Emulate an unconditional br instruction</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3447 switch i32 0, label %dest [ ]
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3448
3449 <i>; Implement a jump table:</i>
Dan Gohman2a08c532009-01-04 23:44:43 +0000[diff] [blame]3450 switch i32 %val, label %otherwise [ i32 0, label %onzero
3451 i32 1, label %onone
3452 i32 2, label %ontwo ]
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3453</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3454
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3455</div>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3456
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]3457
3458<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3459<h4>
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]3460 <a name="i_indirectbr">'<tt>indirectbr</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3461</h4>
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]3462
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3463<div>
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]3464
3465<h5>Syntax:</h5>
3466<pre>
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]3467 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]3468</pre>
3469
3470<h5>Overview:</h5>
3471
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]3472<p>The '<tt>indirectbr</tt>' instruction implements an indirect branch to a label
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]3473 within the current function, whose address is specified by
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]3474 "<tt>address</tt>". Address must be derived from a <a
3475 href="#blockaddress">blockaddress</a> constant.</p>
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]3476
3477<h5>Arguments:</h5>
3478
3479<p>The '<tt>address</tt>' argument is the address of the label to jump to. The
3480 rest of the arguments indicate the full set of possible destinations that the
3481 address may point to. Blocks are allowed to occur multiple times in the
3482 destination list, though this isn't particularly useful.</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3483
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]3484<p>This destination list is required so that dataflow analysis has an accurate
3485 understanding of the CFG.</p>
3486
3487<h5>Semantics:</h5>
3488
3489<p>Control transfers to the block specified in the address argument. All
3490 possible destination blocks must be listed in the label list, otherwise this
3491 instruction has undefined behavior. This implies that jumps to labels
3492 defined in other functions have undefined behavior as well.</p>
3493
3494<h5>Implementation:</h5>
3495
3496<p>This is typically implemented with a jump through a register.</p>
3497
3498<h5>Example:</h5>
3499<pre>
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]3500 indirectbr i8* %Addr, [ label %bb1, label %bb2, label %bb3 ]
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]3501</pre>
3502
3503</div>
3504
3505
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3506<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3507<h4>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3508 <a name="i_invoke">'<tt>invoke</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3509</h4>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3510
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3511<div>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3512
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3513<h5>Syntax:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3514<pre>
Devang Patel307e8ab2008-10-07 17:48:33 +0000[diff] [blame]3515 &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]3516 to label &lt;normal label&gt; unwind label &lt;exception label&gt;
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3517</pre>
3518
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]3519<h5>Overview:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3520<p>The '<tt>invoke</tt>' instruction causes control to transfer to a specified
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3521 function, with the possibility of control flow transfer to either the
3522 '<tt>normal</tt>' label or the '<tt>exception</tt>' label. If the callee
3523 function returns with the "<tt><a href="#i_ret">ret</a></tt>" instruction,
3524 control flow will return to the "normal" label. If the callee (or any
Bill Wendling7b9e5392012-02-06 21:57:33 +0000[diff] [blame]3525 indirect callees) returns via the "<a href="#i_resume"><tt>resume</tt></a>"
3526 instruction or other exception handling mechanism, control is interrupted and
3527 continued at the dynamically nearest "exception" label.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3528
Bill Wendlingf78faf82011-08-02 21:52:38 +0000[diff] [blame]3529<p>The '<tt>exception</tt>' label is a
3530 <i><a href="ExceptionHandling.html#overview">landing pad</a></i> for the
3531 exception. As such, '<tt>exception</tt>' label is required to have the
3532 "<a href="#i_landingpad"><tt>landingpad</tt></a>" instruction, which contains
Chad Rosier85f5a1a2011-12-09 02:00:44 +0000[diff] [blame]3533 the information about the behavior of the program after unwinding
Bill Wendlingf78faf82011-08-02 21:52:38 +0000[diff] [blame]3534 happens, as its first non-PHI instruction. The restrictions on the
3535 "<tt>landingpad</tt>" instruction's tightly couples it to the
3536 "<tt>invoke</tt>" instruction, so that the important information contained
3537 within the "<tt>landingpad</tt>" instruction can't be lost through normal
3538 code motion.</p>
3539
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3540<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3541<p>This instruction requires several arguments:</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3542
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3543<ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3544 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
3545 convention</a> the call should use. If none is specified, the call
3546 defaults to using C calling conventions.</li>
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]3547
3548 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3549 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
3550 '<tt>inreg</tt>' attributes are valid here.</li>
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]3551
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3552 <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]3553 function value being invoked. In most cases, this is a direct function
3554 invocation, but indirect <tt>invoke</tt>s are just as possible, branching
3555 off an arbitrary pointer to function value.</li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3556
3557 <li>'<tt>function ptr val</tt>': An LLVM value containing a pointer to a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3558 function to be invoked. </li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3559
3560 <li>'<tt>function args</tt>': argument list whose types match the function
Chris Lattner0724fbd2010-03-02 06:36:51 +0000[diff] [blame]3561 signature argument types and parameter attributes. All arguments must be
3562 of <a href="#t_firstclass">first class</a> type. If the function
3563 signature indicates the function accepts a variable number of arguments,
3564 the extra arguments can be specified.</li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3565
3566 <li>'<tt>normal label</tt>': the label reached when the called function
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3567 executes a '<tt><a href="#i_ret">ret</a></tt>' instruction. </li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3568
Bill Wendling7b9e5392012-02-06 21:57:33 +0000[diff] [blame]3569 <li>'<tt>exception label</tt>': the label reached when a callee returns via
3570 the <a href="#i_resume"><tt>resume</tt></a> instruction or other exception
3571 handling mechanism.</li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3572
Devang Patel307e8ab2008-10-07 17:48:33 +0000[diff] [blame]3573 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3574 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
3575 '<tt>readnone</tt>' attributes are valid here.</li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3576</ol>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3577
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3578<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3579<p>This instruction is designed to operate as a standard
3580 '<tt><a href="#i_call">call</a></tt>' instruction in most regards. The
3581 primary difference is that it establishes an association with a label, which
3582 is used by the runtime library to unwind the stack.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3583
3584<p>This instruction is used in languages with destructors to ensure that proper
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3585 cleanup is performed in the case of either a <tt>longjmp</tt> or a thrown
3586 exception. Additionally, this is important for implementation of
3587 '<tt>catch</tt>' clauses in high-level languages that support them.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3588
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3589<p>For the purposes of the SSA form, the definition of the value returned by the
3590 '<tt>invoke</tt>' instruction is deemed to occur on the edge from the current
3591 block to the "normal" label. If the callee unwinds then no return value is
3592 available.</p>
Dan Gohmanf96a4992009-05-22 21:47:08 +0000[diff] [blame]3593
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3594<h5>Example:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3595<pre>
Nick Lewyckyd703f652008-03-16 07:18:12 +0000[diff] [blame]3596 %retval = invoke i32 @Test(i32 15) to label %Continue
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]3597 unwind label %TestCleanup <i>; {i32}:retval set</i>
Nick Lewyckyd703f652008-03-16 07:18:12 +0000[diff] [blame]3598 %retval = invoke <a href="#callingconv">coldcc</a> i32 %Testfnptr(i32 15) to label %Continue
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]3599 unwind label %TestCleanup <i>; {i32}:retval set</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3600</pre>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3601
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3602</div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3603
Bill Wendlingdccc03b2011-07-31 06:30:59 +0000[diff] [blame]3604 <!-- _______________________________________________________________________ -->
3605
3606<h4>
3607 <a name="i_resume">'<tt>resume</tt>' Instruction</a>
3608</h4>
3609
3610<div>
3611
3612<h5>Syntax:</h5>
3613<pre>
3614 resume &lt;type&gt; &lt;value&gt;
3615</pre>
3616
3617<h5>Overview:</h5>
3618<p>The '<tt>resume</tt>' instruction is a terminator instruction that has no
3619 successors.</p>
3620
3621<h5>Arguments:</h5>
Bill Wendlingf78faf82011-08-02 21:52:38 +0000[diff] [blame]3622<p>The '<tt>resume</tt>' instruction requires one argument, which must have the
Bill Wendlinge4ad50b2011-08-03 18:37:32 +0000[diff] [blame]3623 same type as the result of any '<tt>landingpad</tt>' instruction in the same
3624 function.</p>
Bill Wendlingdccc03b2011-07-31 06:30:59 +0000[diff] [blame]3625
3626<h5>Semantics:</h5>
3627<p>The '<tt>resume</tt>' instruction resumes propagation of an existing
3628 (in-flight) exception whose unwinding was interrupted with
Bill Wendlingf78faf82011-08-02 21:52:38 +0000[diff] [blame]3629 a <a href="#i_landingpad"><tt>landingpad</tt></a> instruction.</p>
Bill Wendlingdccc03b2011-07-31 06:30:59 +0000[diff] [blame]3630
3631<h5>Example:</h5>
3632<pre>
Bill Wendlingf78faf82011-08-02 21:52:38 +0000[diff] [blame]3633 resume { i8*, i32 } %exn
Bill Wendlingdccc03b2011-07-31 06:30:59 +0000[diff] [blame]3634</pre>
3635
3636</div>
3637
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3638<!-- _______________________________________________________________________ -->
3639
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3640<h4>
3641 <a name="i_unreachable">'<tt>unreachable</tt>' Instruction</a>
3642</h4>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3643
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3644<div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3645
3646<h5>Syntax:</h5>
3647<pre>
3648 unreachable
3649</pre>
3650
3651<h5>Overview:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3652<p>The '<tt>unreachable</tt>' instruction has no defined semantics. This
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3653 instruction is used to inform the optimizer that a particular portion of the
3654 code is not reachable. This can be used to indicate that the code after a
3655 no-return function cannot be reached, and other facts.</p>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3656
3657<h5>Semantics:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3658<p>The '<tt>unreachable</tt>' instruction has no defined semantics.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3659
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3660</div>
3661
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3662</div>
3663
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3664<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3665<h3>
3666 <a name="binaryops">Binary Operations</a>
3667</h3>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3668
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3669<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3670
3671<p>Binary operators are used to do most of the computation in a program. They
3672 require two operands of the same type, execute an operation on them, and
3673 produce a single value. The operands might represent multiple data, as is
3674 the case with the <a href="#t_vector">vector</a> data type. The result value
3675 has the same type as its operands.</p>
3676
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3677<p>There are several different binary operators:</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3678
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3679<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3680<h4>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3681 <a name="i_add">'<tt>add</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3682</h4>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3683
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3684<div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3685
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3686<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3687<pre>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3688 &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]3689 &lt;result&gt; = add nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3690 &lt;result&gt; = add nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3691 &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]3692</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3693
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3694<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3695<p>The '<tt>add</tt>' instruction returns the sum of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3696
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3697<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3698<p>The two arguments to the '<tt>add</tt>' instruction must
3699 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3700 integer values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3701
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3702<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3703<p>The value produced is the integer sum of the two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3704
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3705<p>If the sum has unsigned overflow, the result returned is the mathematical
3706 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]3707
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3708<p>Because LLVM integers use a two's complement representation, this instruction
3709 is appropriate for both signed and unsigned integers.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3710
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]3711<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3712 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3713 <tt>nsw</tt> keywords are present, the result value of the <tt>add</tt>
Dan Gohmanbfb056d2011-12-06 03:18:47 +0000[diff] [blame]3714 is a <a href="#poisonvalues">poison value</a> if unsigned and/or signed overflow,
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]3715 respectively, occurs.</p>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3716
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3717<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3718<pre>
3719 &lt;result&gt; = add i32 4, %var <i>; yields {i32}:result = 4 + %var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3720</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3721
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3722</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3723
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3724<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3725<h4>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3726 <a name="i_fadd">'<tt>fadd</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3727</h4>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3728
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3729<div>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3730
3731<h5>Syntax:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3732<pre>
3733 &lt;result&gt; = fadd &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3734</pre>
3735
3736<h5>Overview:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3737<p>The '<tt>fadd</tt>' instruction returns the sum of its two operands.</p>
3738
3739<h5>Arguments:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3740<p>The two arguments to the '<tt>fadd</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3741 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3742 floating point values. Both arguments must have identical types.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3743
3744<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3745<p>The value produced is the floating point sum of the two operands.</p>
3746
3747<h5>Example:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3748<pre>
3749 &lt;result&gt; = fadd float 4.0, %var <i>; yields {float}:result = 4.0 + %var</i>
3750</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3751
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3752</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3753
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3754<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3755<h4>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3756 <a name="i_sub">'<tt>sub</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3757</h4>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3758
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3759<div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3760
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3761<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3762<pre>
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]3763 &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]3764 &lt;result&gt; = sub nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3765 &lt;result&gt; = sub nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3766 &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]3767</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3768
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3769<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3770<p>The '<tt>sub</tt>' instruction returns the difference of its two
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3771 operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3772
3773<p>Note that the '<tt>sub</tt>' instruction is used to represent the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3774 '<tt>neg</tt>' instruction present in most other intermediate
3775 representations.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3776
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3777<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3778<p>The two arguments to the '<tt>sub</tt>' instruction must
3779 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3780 integer values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3781
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3782<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3783<p>The value produced is the integer difference of the two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3784
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3785<p>If the difference has unsigned overflow, the result returned is the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3786 mathematical result modulo 2<sup>n</sup>, where n is the bit width of the
3787 result.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3788
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3789<p>Because LLVM integers use a two's complement representation, this instruction
3790 is appropriate for both signed and unsigned integers.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3791
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]3792<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3793 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3794 <tt>nsw</tt> keywords are present, the result value of the <tt>sub</tt>
Dan Gohmanbfb056d2011-12-06 03:18:47 +0000[diff] [blame]3795 is a <a href="#poisonvalues">poison value</a> if unsigned and/or signed overflow,
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]3796 respectively, occurs.</p>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3797
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3798<h5>Example:</h5>
Bill Wendlingaac388b2007-05-29 09:42:13 +0000[diff] [blame]3799<pre>
3800 &lt;result&gt; = sub i32 4, %var <i>; yields {i32}:result = 4 - %var</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3801 &lt;result&gt; = sub i32 0, %val <i>; yields {i32}:result = -%var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3802</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3803
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3804</div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3805
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3806<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3807<h4>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3808 <a name="i_fsub">'<tt>fsub</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3809</h4>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3810
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3811<div>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3812
3813<h5>Syntax:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3814<pre>
3815 &lt;result&gt; = fsub &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3816</pre>
3817
3818<h5>Overview:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3819<p>The '<tt>fsub</tt>' instruction returns the difference of its two
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3820 operands.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3821
3822<p>Note that the '<tt>fsub</tt>' instruction is used to represent the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3823 '<tt>fneg</tt>' instruction present in most other intermediate
3824 representations.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3825
3826<h5>Arguments:</h5>
Bill Wendlingd9fe2982009-07-20 02:32:41 +0000[diff] [blame]3827<p>The two arguments to the '<tt>fsub</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3828 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3829 floating point values. Both arguments must have identical types.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3830
3831<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3832<p>The value produced is the floating point difference of the two operands.</p>
3833
3834<h5>Example:</h5>
3835<pre>
3836 &lt;result&gt; = fsub float 4.0, %var <i>; yields {float}:result = 4.0 - %var</i>
3837 &lt;result&gt; = fsub float -0.0, %val <i>; yields {float}:result = -%var</i>
3838</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3839
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3840</div>
3841
3842<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3843<h4>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3844 <a name="i_mul">'<tt>mul</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3845</h4>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3846
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3847<div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3848
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3849<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3850<pre>
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]3851 &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]3852 &lt;result&gt; = mul nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3853 &lt;result&gt; = mul nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3854 &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]3855</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3856
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3857<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3858<p>The '<tt>mul</tt>' instruction returns the product of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3859
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3860<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3861<p>The two arguments to the '<tt>mul</tt>' instruction must
3862 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3863 integer values. Both arguments must have identical types.</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3864
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3865<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3866<p>The value produced is the integer product of the two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3867
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3868<p>If the result of the multiplication has unsigned overflow, the result
3869 returned is the mathematical result modulo 2<sup>n</sup>, where n is the bit
3870 width of the result.</p>
3871
3872<p>Because LLVM integers use a two's complement representation, and the result
3873 is the same width as the operands, this instruction returns the correct
3874 result for both signed and unsigned integers. If a full product
3875 (e.g. <tt>i32</tt>x<tt>i32</tt>-><tt>i64</tt>) is needed, the operands should
3876 be sign-extended or zero-extended as appropriate to the width of the full
3877 product.</p>
3878
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]3879<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3880 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3881 <tt>nsw</tt> keywords are present, the result value of the <tt>mul</tt>
Dan Gohmanbfb056d2011-12-06 03:18:47 +0000[diff] [blame]3882 is a <a href="#poisonvalues">poison value</a> if unsigned and/or signed overflow,
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]3883 respectively, occurs.</p>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3884
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3885<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3886<pre>
3887 &lt;result&gt; = mul i32 4, %var <i>; yields {i32}:result = 4 * %var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3888</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3889
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3890</div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3891
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3892<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3893<h4>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3894 <a name="i_fmul">'<tt>fmul</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3895</h4>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3896
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3897<div>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3898
3899<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3900<pre>
3901 &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]3902</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3903
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3904<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3905<p>The '<tt>fmul</tt>' instruction returns the product of its two operands.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3906
3907<h5>Arguments:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3908<p>The two arguments to the '<tt>fmul</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3909 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3910 floating point values. Both arguments must have identical types.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3911
3912<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3913<p>The value produced is the floating point product of the two operands.</p>
3914
3915<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3916<pre>
3917 &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]3918</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3919
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3920</div>
3921
3922<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3923<h4>
3924 <a name="i_udiv">'<tt>udiv</tt>' Instruction</a>
3925</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3926
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3927<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3928
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3929<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3930<pre>
Chris Lattner35bda892011-02-06 21:44:57 +0000[diff] [blame]3931 &lt;result&gt; = udiv &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3932 &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]3933</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3934
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3935<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3936<p>The '<tt>udiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3937
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3938<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3939<p>The two arguments to the '<tt>udiv</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3940 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3941 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3942
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3943<h5>Semantics:</h5>
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3944<p>The value produced is the unsigned integer quotient of the two operands.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3945
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3946<p>Note that unsigned integer division and signed integer division are distinct
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3947 operations; for signed integer division, use '<tt>sdiv</tt>'.</p>
3948
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3949<p>Division by zero leads to undefined behavior.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3950
Chris Lattner35bda892011-02-06 21:44:57 +0000[diff] [blame]3951<p>If the <tt>exact</tt> keyword is present, the result value of the
Dan Gohmanbfb056d2011-12-06 03:18:47 +0000[diff] [blame]3952 <tt>udiv</tt> is a <a href="#poisonvalues">poison value</a> if %op1 is not a
Chris Lattner35bda892011-02-06 21:44:57 +0000[diff] [blame]3953 multiple of %op2 (as such, "((a udiv exact b) mul b) == a").</p>
3954
3955
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3956<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3957<pre>
3958 &lt;result&gt; = udiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3959</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3960
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3961</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3962
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3963<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3964<h4>
3965 <a name="i_sdiv">'<tt>sdiv</tt>' Instruction</a>
3966</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3967
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3968<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3969
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3970<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3971<pre>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3972 &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]3973 &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]3974</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3975
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3976<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3977<p>The '<tt>sdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3978
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3979<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3980<p>The two arguments to the '<tt>sdiv</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3981 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3982 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3983
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3984<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3985<p>The value produced is the signed integer quotient of the two operands rounded
3986 towards zero.</p>
3987
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3988<p>Note that signed integer division and unsigned integer division are distinct
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3989 operations; for unsigned integer division, use '<tt>udiv</tt>'.</p>
3990
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3991<p>Division by zero leads to undefined behavior. Overflow also leads to
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3992 undefined behavior; this is a rare case, but can occur, for example, by doing
3993 a 32-bit division of -2147483648 by -1.</p>
3994
Dan Gohman9c5beed2009-07-22 00:04:19 +0000[diff] [blame]3995<p>If the <tt>exact</tt> keyword is present, the result value of the
Dan Gohmanbfb056d2011-12-06 03:18:47 +0000[diff] [blame]3996 <tt>sdiv</tt> is a <a href="#poisonvalues">poison value</a> if the result would
Dan Gohman38da9272010-07-11 00:08:34 +0000[diff] [blame]3997 be rounded.</p>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3998
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3999<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4000<pre>
4001 &lt;result&gt; = sdiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]4002</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4003
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]4004</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4005
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]4006<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4007<h4>
4008 <a name="i_fdiv">'<tt>fdiv</tt>' Instruction</a>
4009</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4010
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4011<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4012
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4013<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4014<pre>
Gabor Greiffb224a22008-08-07 21:46:00 +0000[diff] [blame]4015 &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]4016</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4017
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4018<h5>Overview:</h5>
4019<p>The '<tt>fdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4020
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4021<h5>Arguments:</h5>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]4022<p>The two arguments to the '<tt>fdiv</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4023 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
4024 floating point values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4025
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4026<h5>Semantics:</h5>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]4027<p>The value produced is the floating point quotient of the two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4028
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4029<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4030<pre>
4031 &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]4032</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4033
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4034</div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4035
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4036<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4037<h4>
4038 <a name="i_urem">'<tt>urem</tt>' Instruction</a>
4039</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4040
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4041<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4042
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]4043<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4044<pre>
4045 &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]4046</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4047
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]4048<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4049<p>The '<tt>urem</tt>' instruction returns the remainder from the unsigned
4050 division of its two arguments.</p>
4051
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]4052<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4053<p>The two arguments to the '<tt>urem</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4054 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
4055 values. Both arguments must have identical types.</p>
4056
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]4057<h5>Semantics:</h5>
4058<p>This instruction returns the unsigned integer <i>remainder</i> of a division.
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4059 This instruction always performs an unsigned division to get the
4060 remainder.</p>
4061
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]4062<p>Note that unsigned integer remainder and signed integer remainder are
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4063 distinct operations; for signed integer remainder, use '<tt>srem</tt>'.</p>
4064
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]4065<p>Taking the remainder of a division by zero leads to undefined behavior.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4066
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]4067<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4068<pre>
4069 &lt;result&gt; = urem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]4070</pre>
4071
4072</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4073
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]4074<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4075<h4>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4076 <a name="i_srem">'<tt>srem</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4077</h4>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4078
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4079<div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4080
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4081<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4082<pre>
Gabor Greiffb224a22008-08-07 21:46:00 +0000[diff] [blame]4083 &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]4084</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4085
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4086<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4087<p>The '<tt>srem</tt>' instruction returns the remainder from the signed
4088 division of its two operands. This instruction can also take
4089 <a href="#t_vector">vector</a> versions of the values in which case the
4090 elements must be integers.</p>
Chris Lattnerc7d3ab32008-01-04 04:33:49 +0000[diff] [blame]4091
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4092<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4093<p>The two arguments to the '<tt>srem</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4094 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
4095 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4096
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4097<h5>Semantics:</h5>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]4098<p>This instruction returns the <i>remainder</i> of a division (where the result
Duncan Sandsdea3a5e2011-03-07 09:12:24 +0000[diff] [blame]4099 is either zero or has the same sign as the dividend, <tt>op1</tt>), not the
4100 <i>modulo</i> operator (where the result is either zero or has the same sign
4101 as the divisor, <tt>op2</tt>) of a value.
4102 For more information about the difference,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4103 see <a href="http://mathforum.org/dr.math/problems/anne.4.28.99.html">The
4104 Math Forum</a>. For a table of how this is implemented in various languages,
4105 please see <a href="http://en.wikipedia.org/wiki/Modulo_operation">
4106 Wikipedia: modulo operation</a>.</p>
4107
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]4108<p>Note that signed integer remainder and unsigned integer remainder are
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4109 distinct operations; for unsigned integer remainder, use '<tt>urem</tt>'.</p>
4110
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]4111<p>Taking the remainder of a division by zero leads to undefined behavior.
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4112 Overflow also leads to undefined behavior; this is a rare case, but can
4113 occur, for example, by taking the remainder of a 32-bit division of
4114 -2147483648 by -1. (The remainder doesn't actually overflow, but this rule
4115 lets srem be implemented using instructions that return both the result of
4116 the division and the remainder.)</p>
4117
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4118<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4119<pre>
4120 &lt;result&gt; = srem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]4121</pre>
4122
4123</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4124
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]4125<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4126<h4>
4127 <a name="i_frem">'<tt>frem</tt>' Instruction</a>
4128</h4>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4129
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4130<div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4131
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]4132<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4133<pre>
4134 &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]4135</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4136
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]4137<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4138<p>The '<tt>frem</tt>' instruction returns the remainder from the division of
4139 its two operands.</p>
4140
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]4141<h5>Arguments:</h5>
4142<p>The two arguments to the '<tt>frem</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4143 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
4144 floating point values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4145
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]4146<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4147<p>This instruction returns the <i>remainder</i> of a division. The remainder
4148 has the same sign as the dividend.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4149
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]4150<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4151<pre>
4152 &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]4153</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4154
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4155</div>
Robert Bocchino7b81c752006-02-17 21:18:08 +0000[diff] [blame]4156
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4157</div>
4158
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]4159<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4160<h3>
4161 <a name="bitwiseops">Bitwise Binary Operations</a>
4162</h3>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4163
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4164<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4165
4166<p>Bitwise binary operators are used to do various forms of bit-twiddling in a
4167 program. They are generally very efficient instructions and can commonly be
4168 strength reduced from other instructions. They require two operands of the
4169 same type, execute an operation on them, and produce a single value. The
4170 resulting value is the same type as its operands.</p>
4171
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4172<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4173<h4>
4174 <a name="i_shl">'<tt>shl</tt>' Instruction</a>
4175</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4176
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4177<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4178
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4179<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4180<pre>
Chris Lattnerf067d582011-02-07 16:40:21 +0000[diff] [blame]4181 &lt;result&gt; = shl &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
4182 &lt;result&gt; = shl nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
4183 &lt;result&gt; = shl nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
4184 &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]4185</pre>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]4186
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4187<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4188<p>The '<tt>shl</tt>' instruction returns the first operand shifted to the left
4189 a specified number of bits.</p>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]4190
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4191<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4192<p>Both arguments to the '<tt>shl</tt>' instruction must be the
4193 same <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
4194 integer type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4195
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4196<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4197<p>The value produced is <tt>op1</tt> * 2<sup><tt>op2</tt></sup> mod
4198 2<sup>n</sup>, where <tt>n</tt> is the width of the result. If <tt>op2</tt>
4199 is (statically or dynamically) negative or equal to or larger than the number
4200 of bits in <tt>op1</tt>, the result is undefined. If the arguments are
4201 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
4202 shift amount in <tt>op2</tt>.</p>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]4203
Chris Lattnerf067d582011-02-07 16:40:21 +0000[diff] [blame]4204<p>If the <tt>nuw</tt> keyword is present, then the shift produces a
Dan Gohmanbfb056d2011-12-06 03:18:47 +0000[diff] [blame]4205 <a href="#poisonvalues">poison value</a> if it shifts out any non-zero bits. If
Chris Lattner66298c12011-02-09 16:44:44 +0000[diff] [blame]4206 the <tt>nsw</tt> keyword is present, then the shift produces a
Dan Gohmanbfb056d2011-12-06 03:18:47 +0000[diff] [blame]4207 <a href="#poisonvalues">poison value</a> if it shifts out any bits that disagree
Chris Lattnerf067d582011-02-07 16:40:21 +0000[diff] [blame]4208 with the resultant sign bit. As such, NUW/NSW have the same semantics as
4209 they would if the shift were expressed as a mul instruction with the same
4210 nsw/nuw bits in (mul %op1, (shl 1, %op2)).</p>
4211
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4212<h5>Example:</h5>
4213<pre>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4214 &lt;result&gt; = shl i32 4, %var <i>; yields {i32}: 4 &lt;&lt; %var</i>
4215 &lt;result&gt; = shl i32 4, 2 <i>; yields {i32}: 16</i>
4216 &lt;result&gt; = shl i32 1, 10 <i>; yields {i32}: 1024</i>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]4217 &lt;result&gt; = shl i32 1, 32 <i>; undefined</i>
Mon P Wange9f10152008-12-09 05:46:39 +0000[diff] [blame]4218 &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]4219</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4220
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4221</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4222
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4223<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4224<h4>
4225 <a name="i_lshr">'<tt>lshr</tt>' Instruction</a>
4226</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4227
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4228<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4229
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4230<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4231<pre>
Chris Lattnerf067d582011-02-07 16:40:21 +0000[diff] [blame]4232 &lt;result&gt; = lshr &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
4233 &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]4234</pre>
4235
4236<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4237<p>The '<tt>lshr</tt>' instruction (logical shift right) returns the first
4238 operand shifted to the right a specified number of bits with zero fill.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4239
4240<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4241<p>Both arguments to the '<tt>lshr</tt>' instruction must be the same
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4242 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
4243 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4244
4245<h5>Semantics:</h5>
4246<p>This instruction always performs a logical shift right operation. The most
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4247 significant bits of the result will be filled with zero bits after the shift.
4248 If <tt>op2</tt> is (statically or dynamically) equal to or larger than the
4249 number of bits in <tt>op1</tt>, the result is undefined. If the arguments are
4250 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
4251 shift amount in <tt>op2</tt>.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4252
Chris Lattnerf067d582011-02-07 16:40:21 +0000[diff] [blame]4253<p>If the <tt>exact</tt> keyword is present, the result value of the
Dan Gohmanbfb056d2011-12-06 03:18:47 +0000[diff] [blame]4254 <tt>lshr</tt> is a <a href="#poisonvalues">poison value</a> if any of the bits
Chris Lattnerf067d582011-02-07 16:40:21 +0000[diff] [blame]4255 shifted out are non-zero.</p>
4256
4257
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4258<h5>Example:</h5>
4259<pre>
4260 &lt;result&gt; = lshr i32 4, 1 <i>; yields {i32}:result = 2</i>
4261 &lt;result&gt; = lshr i32 4, 2 <i>; yields {i32}:result = 1</i>
4262 &lt;result&gt; = lshr i8 4, 3 <i>; yields {i8}:result = 0</i>
4263 &lt;result&gt; = lshr i8 -2, 1 <i>; yields {i8}:result = 0x7FFFFFFF </i>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]4264 &lt;result&gt; = lshr i32 1, 32 <i>; undefined</i>
Mon P Wange9f10152008-12-09 05:46:39 +0000[diff] [blame]4265 &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]4266</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4267
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4268</div>
4269
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]4270<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4271<h4>
4272 <a name="i_ashr">'<tt>ashr</tt>' Instruction</a>
4273</h4>
4274
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4275<div>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4276
4277<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4278<pre>
Chris Lattnerf067d582011-02-07 16:40:21 +0000[diff] [blame]4279 &lt;result&gt; = ashr &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
4280 &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]4281</pre>
4282
4283<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4284<p>The '<tt>ashr</tt>' instruction (arithmetic shift right) returns the first
4285 operand shifted to the right a specified number of bits with sign
4286 extension.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4287
4288<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4289<p>Both arguments to the '<tt>ashr</tt>' instruction must be the same
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4290 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
4291 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4292
4293<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4294<p>This instruction always performs an arithmetic shift right operation, The
4295 most significant bits of the result will be filled with the sign bit
4296 of <tt>op1</tt>. If <tt>op2</tt> is (statically or dynamically) equal to or
4297 larger than the number of bits in <tt>op1</tt>, the result is undefined. If
4298 the arguments are vectors, each vector element of <tt>op1</tt> is shifted by
4299 the corresponding shift amount in <tt>op2</tt>.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4300
Chris Lattnerf067d582011-02-07 16:40:21 +0000[diff] [blame]4301<p>If the <tt>exact</tt> keyword is present, the result value of the
Dan Gohmanbfb056d2011-12-06 03:18:47 +0000[diff] [blame]4302 <tt>ashr</tt> is a <a href="#poisonvalues">poison value</a> if any of the bits
Chris Lattnerf067d582011-02-07 16:40:21 +0000[diff] [blame]4303 shifted out are non-zero.</p>
4304
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4305<h5>Example:</h5>
4306<pre>
4307 &lt;result&gt; = ashr i32 4, 1 <i>; yields {i32}:result = 2</i>
4308 &lt;result&gt; = ashr i32 4, 2 <i>; yields {i32}:result = 1</i>
4309 &lt;result&gt; = ashr i8 4, 3 <i>; yields {i8}:result = 0</i>
4310 &lt;result&gt; = ashr i8 -2, 1 <i>; yields {i8}:result = -1</i>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]4311 &lt;result&gt; = ashr i32 1, 32 <i>; undefined</i>
Mon P Wange9f10152008-12-09 05:46:39 +0000[diff] [blame]4312 &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]4313</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4314
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4315</div>
4316
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4317<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4318<h4>
4319 <a name="i_and">'<tt>and</tt>' Instruction</a>
4320</h4>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4321
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4322<div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4323
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4324<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4325<pre>
Gabor Greiffb224a22008-08-07 21:46:00 +0000[diff] [blame]4326 &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]4327</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4328
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4329<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4330<p>The '<tt>and</tt>' instruction returns the bitwise logical and of its two
4331 operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4332
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4333<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4334<p>The two arguments to the '<tt>and</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4335 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
4336 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4337
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4338<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4339<p>The truth table used for the '<tt>and</tt>' instruction is:</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4340
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4341<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4342 <tbody>
4343 <tr>
Bill Wendling262396b2011-12-09 22:41:40 +0000[diff] [blame]4344 <th>In0</th>
4345 <th>In1</th>
4346 <th>Out</th>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4347 </tr>
4348 <tr>
4349 <td>0</td>
4350 <td>0</td>
4351 <td>0</td>
4352 </tr>
4353 <tr>
4354 <td>0</td>
4355 <td>1</td>
4356 <td>0</td>
4357 </tr>
4358 <tr>
4359 <td>1</td>
4360 <td>0</td>
4361 <td>0</td>
4362 </tr>
4363 <tr>
4364 <td>1</td>
4365 <td>1</td>
4366 <td>1</td>
4367 </tr>
4368 </tbody>
4369</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4370
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4371<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4372<pre>
4373 &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]4374 &lt;result&gt; = and i32 15, 40 <i>; yields {i32}:result = 8</i>
4375 &lt;result&gt; = and i32 4, 8 <i>; yields {i32}:result = 0</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4376</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4377</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4378<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4379<h4>
4380 <a name="i_or">'<tt>or</tt>' Instruction</a>
4381</h4>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4382
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4383<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4384
4385<h5>Syntax:</h5>
4386<pre>
4387 &lt;result&gt; = or &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
4388</pre>
4389
4390<h5>Overview:</h5>
4391<p>The '<tt>or</tt>' instruction returns the bitwise logical inclusive or of its
4392 two operands.</p>
4393
4394<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4395<p>The two arguments to the '<tt>or</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4396 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
4397 values. Both arguments must have identical types.</p>
4398
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4399<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4400<p>The truth table used for the '<tt>or</tt>' instruction is:</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4401
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4402<table border="1" cellspacing="0" cellpadding="4">
4403 <tbody>
4404 <tr>
Bill Wendling262396b2011-12-09 22:41:40 +0000[diff] [blame]4405 <th>In0</th>
4406 <th>In1</th>
4407 <th>Out</th>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4408 </tr>
4409 <tr>
4410 <td>0</td>
4411 <td>0</td>
4412 <td>0</td>
4413 </tr>
4414 <tr>
4415 <td>0</td>
4416 <td>1</td>
4417 <td>1</td>
4418 </tr>
4419 <tr>
4420 <td>1</td>
4421 <td>0</td>
4422 <td>1</td>
4423 </tr>
4424 <tr>
4425 <td>1</td>
4426 <td>1</td>
4427 <td>1</td>
4428 </tr>
4429 </tbody>
4430</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4431
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4432<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4433<pre>
4434 &lt;result&gt; = or i32 4, %var <i>; yields {i32}:result = 4 | %var</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4435 &lt;result&gt; = or i32 15, 40 <i>; yields {i32}:result = 47</i>
4436 &lt;result&gt; = or i32 4, 8 <i>; yields {i32}:result = 12</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4437</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4438
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4439</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4440
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4441<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4442<h4>
4443 <a name="i_xor">'<tt>xor</tt>' Instruction</a>
4444</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4445
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4446<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4447
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4448<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4449<pre>
4450 &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]4451</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4452
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4453<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4454<p>The '<tt>xor</tt>' instruction returns the bitwise logical exclusive or of
4455 its two operands. The <tt>xor</tt> is used to implement the "one's
4456 complement" operation, which is the "~" operator in C.</p>
4457
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4458<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4459<p>The two arguments to the '<tt>xor</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4460 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
4461 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4462
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4463<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4464<p>The truth table used for the '<tt>xor</tt>' instruction is:</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4465
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4466<table border="1" cellspacing="0" cellpadding="4">
4467 <tbody>
4468 <tr>
Bill Wendling262396b2011-12-09 22:41:40 +0000[diff] [blame]4469 <th>In0</th>
4470 <th>In1</th>
4471 <th>Out</th>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4472 </tr>
4473 <tr>
4474 <td>0</td>
4475 <td>0</td>
4476 <td>0</td>
4477 </tr>
4478 <tr>
4479 <td>0</td>
4480 <td>1</td>
4481 <td>1</td>
4482 </tr>
4483 <tr>
4484 <td>1</td>
4485 <td>0</td>
4486 <td>1</td>
4487 </tr>
4488 <tr>
4489 <td>1</td>
4490 <td>1</td>
4491 <td>0</td>
4492 </tr>
4493 </tbody>
4494</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4495
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4496<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4497<pre>
4498 &lt;result&gt; = xor i32 4, %var <i>; yields {i32}:result = 4 ^ %var</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4499 &lt;result&gt; = xor i32 15, 40 <i>; yields {i32}:result = 39</i>
4500 &lt;result&gt; = xor i32 4, 8 <i>; yields {i32}:result = 12</i>
4501 &lt;result&gt; = xor i32 %V, -1 <i>; yields {i32}:result = ~%V</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4502</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4503
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4504</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4505
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4506</div>
4507
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4508<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4509<h3>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4510 <a name="vectorops">Vector Operations</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4511</h3>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4512
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4513<div>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4514
4515<p>LLVM supports several instructions to represent vector operations in a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4516 target-independent manner. These instructions cover the element-access and
4517 vector-specific operations needed to process vectors effectively. While LLVM
4518 does directly support these vector operations, many sophisticated algorithms
4519 will want to use target-specific intrinsics to take full advantage of a
4520 specific target.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4521
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4522<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4523<h4>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4524 <a name="i_extractelement">'<tt>extractelement</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4525</h4>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4526
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4527<div>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4528
4529<h5>Syntax:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4530<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4531 &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]4532</pre>
4533
4534<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4535<p>The '<tt>extractelement</tt>' instruction extracts a single scalar element
4536 from a vector at a specified index.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4537
4538
4539<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4540<p>The first operand of an '<tt>extractelement</tt>' instruction is a value
4541 of <a href="#t_vector">vector</a> type. The second operand is an index
4542 indicating the position from which to extract the element. The index may be
4543 a variable.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4544
4545<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4546<p>The result is a scalar of the same type as the element type of
4547 <tt>val</tt>. Its value is the value at position <tt>idx</tt> of
4548 <tt>val</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
4549 results are undefined.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4550
4551<h5>Example:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4552<pre>
Gabor Greifa5b6f452009-10-28 13:14:50 +0000[diff] [blame]4553 &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]4554</pre>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4555
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4556</div>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4557
4558<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4559<h4>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4560 <a name="i_insertelement">'<tt>insertelement</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4561</h4>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4562
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4563<div>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4564
4565<h5>Syntax:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4566<pre>
Dan Gohmanf3480b92008-05-12 23:38:42 +0000[diff] [blame]4567 &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]4568</pre>
4569
4570<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4571<p>The '<tt>insertelement</tt>' instruction inserts a scalar element into a
4572 vector at a specified index.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4573
4574<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4575<p>The first operand of an '<tt>insertelement</tt>' instruction is a value
4576 of <a href="#t_vector">vector</a> type. The second operand is a scalar value
4577 whose type must equal the element type of the first operand. The third
4578 operand is an index indicating the position at which to insert the value.
4579 The index may be a variable.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4580
4581<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4582<p>The result is a vector of the same type as <tt>val</tt>. Its element values
4583 are those of <tt>val</tt> except at position <tt>idx</tt>, where it gets the
4584 value <tt>elt</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
4585 results are undefined.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4586
4587<h5>Example:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4588<pre>
Gabor Greifa5b6f452009-10-28 13:14:50 +0000[diff] [blame]4589 &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]4590</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4591
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4592</div>
4593
4594<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4595<h4>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4596 <a name="i_shufflevector">'<tt>shufflevector</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4597</h4>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4598
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4599<div>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4600
4601<h5>Syntax:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4602<pre>
Mon P Wangaeb06d22008-11-10 04:46:22 +0000[diff] [blame]4603 &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]4604</pre>
4605
4606<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4607<p>The '<tt>shufflevector</tt>' instruction constructs a permutation of elements
4608 from two input vectors, returning a vector with the same element type as the
4609 input and length that is the same as the shuffle mask.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4610
4611<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4612<p>The first two operands of a '<tt>shufflevector</tt>' instruction are vectors
4613 with types that match each other. The third argument is a shuffle mask whose
4614 element type is always 'i32'. The result of the instruction is a vector
4615 whose length is the same as the shuffle mask and whose element type is the
4616 same as the element type of the first two operands.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4617
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4618<p>The shuffle mask operand is required to be a constant vector with either
4619 constant integer or undef values.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4620
4621<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4622<p>The elements of the two input vectors are numbered from left to right across
4623 both of the vectors. The shuffle mask operand specifies, for each element of
4624 the result vector, which element of the two input vectors the result element
4625 gets. The element selector may be undef (meaning "don't care") and the
4626 second operand may be undef if performing a shuffle from only one vector.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4627
4628<h5>Example:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4629<pre>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4630 &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]4631 &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]4632 &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]4633 &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]4634 &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]4635 &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]4636 &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]4637 &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]4638</pre>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4639
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4640</div>
Tanya Lattner09474292006-04-14 19:24:33 +0000[diff] [blame]4641
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4642</div>
4643
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4644<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4645<h3>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4646 <a name="aggregateops">Aggregate Operations</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4647</h3>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4648
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4649<div>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4650
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4651<p>LLVM supports several instructions for working with
4652 <a href="#t_aggregate">aggregate</a> values.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4653
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4654<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4655<h4>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4656 <a name="i_extractvalue">'<tt>extractvalue</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4657</h4>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4658
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4659<div>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4660
4661<h5>Syntax:</h5>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4662<pre>
4663 &lt;result&gt; = extractvalue &lt;aggregate type&gt; &lt;val&gt;, &lt;idx&gt;{, &lt;idx&gt;}*
4664</pre>
4665
4666<h5>Overview:</h5>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4667<p>The '<tt>extractvalue</tt>' instruction extracts the value of a member field
4668 from an <a href="#t_aggregate">aggregate</a> value.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4669
4670<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4671<p>The first operand of an '<tt>extractvalue</tt>' instruction is a value
Chris Lattner61c70e92010-08-28 04:09:24 +0000[diff] [blame]4672 of <a href="#t_struct">struct</a> or
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4673 <a href="#t_array">array</a> type. The operands are constant indices to
4674 specify which value to extract in a similar manner as indices in a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4675 '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
Frits van Bommel13242892010-12-05 20:54:38 +0000[diff] [blame]4676 <p>The major differences to <tt>getelementptr</tt> indexing are:</p>
4677 <ul>
4678 <li>Since the value being indexed is not a pointer, the first index is
4679 omitted and assumed to be zero.</li>
4680 <li>At least one index must be specified.</li>
4681 <li>Not only struct indices but also array indices must be in
4682 bounds.</li>
4683 </ul>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4684
4685<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4686<p>The result is the value at the position in the aggregate specified by the
4687 index operands.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4688
4689<h5>Example:</h5>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4690<pre>
Gabor Greifa5b6f452009-10-28 13:14:50 +0000[diff] [blame]4691 &lt;result&gt; = extractvalue {i32, float} %agg, 0 <i>; yields i32</i>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4692</pre>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4693
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4694</div>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4695
4696<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4697<h4>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4698 <a name="i_insertvalue">'<tt>insertvalue</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4699</h4>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4700
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4701<div>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4702
4703<h5>Syntax:</h5>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4704<pre>
Bill Wendling194229e2011-07-26 20:42:28 +0000[diff] [blame]4705 &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]4706</pre>
4707
4708<h5>Overview:</h5>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4709<p>The '<tt>insertvalue</tt>' instruction inserts a value into a member field
4710 in an <a href="#t_aggregate">aggregate</a> value.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4711
4712<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4713<p>The first operand of an '<tt>insertvalue</tt>' instruction is a value
Chris Lattner61c70e92010-08-28 04:09:24 +0000[diff] [blame]4714 of <a href="#t_struct">struct</a> or
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4715 <a href="#t_array">array</a> type. The second operand is a first-class
4716 value to insert. The following operands are constant indices indicating
4717 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]4718 '<tt><a href="#i_extractvalue">extractvalue</a></tt>' instruction. The
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4719 value to insert must have the same type as the value identified by the
4720 indices.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4721
4722<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4723<p>The result is an aggregate of the same type as <tt>val</tt>. Its value is
4724 that of <tt>val</tt> except that the value at the position specified by the
4725 indices is that of <tt>elt</tt>.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4726
4727<h5>Example:</h5>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4728<pre>
Chris Lattner8645d1a2011-05-22 07:18:08 +0000[diff] [blame]4729 %agg1 = insertvalue {i32, float} undef, i32 1, 0 <i>; yields {i32 1, float undef}</i>
4730 %agg2 = insertvalue {i32, float} %agg1, float %val, 1 <i>; yields {i32 1, float %val}</i>
4731 %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]4732</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4733
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4734</div>
4735
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4736</div>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4737
4738<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4739<h3>
Chris Lattner884a9702006-08-15 00:45:58 +0000[diff] [blame]4740 <a name="memoryops">Memory Access and Addressing Operations</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4741</h3>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4742
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4743<div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4744
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4745<p>A key design point of an SSA-based representation is how it represents
4746 memory. In LLVM, no memory locations are in SSA form, which makes things
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]4747 very simple. This section describes how to read, write, and allocate
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4748 memory in LLVM.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4749
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4750<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4751<h4>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4752 <a name="i_alloca">'<tt>alloca</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4753</h4>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4754
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4755<div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4756
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4757<h5>Syntax:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4758<pre>
Dan Gohmanf75a7d32010-05-28 01:14:11 +0000[diff] [blame]4759 &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]4760</pre>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4761
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4762<h5>Overview:</h5>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]4763<p>The '<tt>alloca</tt>' instruction allocates memory on the stack frame of the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4764 currently executing function, to be automatically released when this function
4765 returns to its caller. The object is always allocated in the generic address
4766 space (address space zero).</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4767
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4768<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4769<p>The '<tt>alloca</tt>' instruction
4770 allocates <tt>sizeof(&lt;type&gt;)*NumElements</tt> bytes of memory on the
4771 runtime stack, returning a pointer of the appropriate type to the program.
4772 If "NumElements" is specified, it is the number of elements allocated,
4773 otherwise "NumElements" is defaulted to be one. If a constant alignment is
4774 specified, the value result of the allocation is guaranteed to be aligned to
4775 at least that boundary. If not specified, or if zero, the target can choose
4776 to align the allocation on any convenient boundary compatible with the
4777 type.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4778
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4779<p>'<tt>type</tt>' may be any sized type.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4780
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4781<h5>Semantics:</h5>
Bill Wendling871eb0a2009-05-08 20:49:29 +0000[diff] [blame]4782<p>Memory is allocated; a pointer is returned. The operation is undefined if
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4783 there is insufficient stack space for the allocation. '<tt>alloca</tt>'d
4784 memory is automatically released when the function returns. The
4785 '<tt>alloca</tt>' instruction is commonly used to represent automatic
4786 variables that must have an address available. When the function returns
4787 (either with the <tt><a href="#i_ret">ret</a></tt>
Bill Wendling7b9e5392012-02-06 21:57:33 +0000[diff] [blame]4788 or <tt><a href="#i_resume">resume</a></tt> instructions), the memory is
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4789 reclaimed. Allocating zero bytes is legal, but the result is undefined.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4790
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4791<h5>Example:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4792<pre>
Dan Gohman81e21672009-01-04 23:49:44 +0000[diff] [blame]4793 %ptr = alloca i32 <i>; yields {i32*}:ptr</i>
4794 %ptr = alloca i32, i32 4 <i>; yields {i32*}:ptr</i>
4795 %ptr = alloca i32, i32 4, align 1024 <i>; yields {i32*}:ptr</i>
4796 %ptr = alloca i32, align 1024 <i>; yields {i32*}:ptr</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4797</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4798
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4799</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4800
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4801<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4802<h4>
4803 <a name="i_load">'<tt>load</tt>' Instruction</a>
4804</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4805
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4806<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4807
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4808<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4809<pre>
Pete Cooperf95acc62012-02-10 18:13:54 +0000[diff] [blame]4810 &lt;result&gt; = load [volatile] &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;][, !nontemporal !&lt;index&gt;][, !invariant.load !&lt;index&gt;]
Eli Friedmanf03bb262011-08-12 22:50:01 +0000[diff] [blame]4811 &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]4812 !&lt;index&gt; = !{ i32 1 }
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4813</pre>
4814
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4815<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4816<p>The '<tt>load</tt>' instruction is used to read from memory.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4817
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4818<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4819<p>The argument to the '<tt>load</tt>' instruction specifies the memory address
4820 from which to load. The pointer must point to
4821 a <a href="#t_firstclass">first class</a> type. If the <tt>load</tt> is
4822 marked as <tt>volatile</tt>, then the optimizer is not allowed to modify the
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]4823 number or order of execution of this <tt>load</tt> with other <a
4824 href="#volatile">volatile operations</a>.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4825
Eli Friedman21006d42011-08-09 23:02:53 +0000[diff] [blame]4826<p>If the <code>load</code> is marked as <code>atomic</code>, it takes an extra
4827 <a href="#ordering">ordering</a> and optional <code>singlethread</code>
4828 argument. The <code>release</code> and <code>acq_rel</code> orderings are
4829 not valid on <code>load</code> instructions. Atomic loads produce <a
4830 href="#memorymodel">defined</a> results when they may see multiple atomic
4831 stores. The type of the pointee must be an integer type whose bit width
4832 is a power of two greater than or equal to eight and less than or equal
4833 to a target-specific size limit. <code>align</code> must be explicitly
4834 specified on atomic loads, and the load has undefined behavior if the
4835 alignment is not set to a value which is at least the size in bytes of
4836 the pointee. <code>!nontemporal</code> does not have any defined semantics
4837 for atomic loads.</p>
4838
Bill Wendling7c78dbb2010-02-25 21:23:24 +0000[diff] [blame]4839<p>The optional constant <tt>align</tt> argument specifies the alignment of the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4840 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]4841 omitted <tt>align</tt> argument means that the operation has the preferential
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4842 alignment for the target. It is the responsibility of the code emitter to
4843 ensure that the alignment information is correct. Overestimating the
Bill Wendling7c78dbb2010-02-25 21:23:24 +0000[diff] [blame]4844 alignment results in undefined behavior. Underestimating the alignment may
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4845 produce less efficient code. An alignment of 1 is always safe.</p>
4846
Bill Wendling7c78dbb2010-02-25 21:23:24 +0000[diff] [blame]4847<p>The optional <tt>!nontemporal</tt> metadata must reference a single
4848 metatadata name &lt;index&gt; corresponding to a metadata node with
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]4849 one <tt>i32</tt> entry of value 1. The existence of
Bill Wendling7c78dbb2010-02-25 21:23:24 +0000[diff] [blame]4850 the <tt>!nontemporal</tt> metatadata on the instruction tells the optimizer
4851 and code generator that this load is not expected to be reused in the cache.
4852 The code generator may select special instructions to save cache bandwidth,
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]4853 such as the <tt>MOVNT</tt> instruction on x86.</p>
David Greene8939b0d2010-02-16 20:50:18 +0000[diff] [blame]4854
Pete Cooperf95acc62012-02-10 18:13:54 +0000[diff] [blame]4855<p>The optional <tt>!invariant.load</tt> metadata must reference a single
4856 metatadata name &lt;index&gt; corresponding to a metadata node with no
4857 entries. The existence of the <tt>!invariant.load</tt> metatadata on the
4858 instruction tells the optimizer and code generator that this load address
4859 points to memory which does not change value during program execution.
4860 The optimizer may then move this load around, for example, by hoisting it
4861 out of loops using loop invariant code motion.</p>
4862
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4863<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4864<p>The location of memory pointed to is loaded. If the value being loaded is of
4865 scalar type then the number of bytes read does not exceed the minimum number
4866 of bytes needed to hold all bits of the type. For example, loading an
4867 <tt>i24</tt> reads at most three bytes. When loading a value of a type like
4868 <tt>i20</tt> with a size that is not an integral number of bytes, the result
4869 is undefined if the value was not originally written using a store of the
4870 same type.</p>
4871
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4872<h5>Examples:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4873<pre>
4874 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
4875 <a href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4876 %val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4877</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4878
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4879</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4880
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4881<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4882<h4>
4883 <a name="i_store">'<tt>store</tt>' Instruction</a>
4884</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4885
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4886<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4887
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4888<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4889<pre>
Bill Wendling262396b2011-12-09 22:41:40 +0000[diff] [blame]4890 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>
4891 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]4892</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4893
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4894<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4895<p>The '<tt>store</tt>' instruction is used to write to memory.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4896
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4897<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4898<p>There are two arguments to the '<tt>store</tt>' instruction: a value to store
4899 and an address at which to store it. The type of the
4900 '<tt>&lt;pointer&gt;</tt>' operand must be a pointer to
4901 the <a href="#t_firstclass">first class</a> type of the
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]4902 '<tt>&lt;value&gt;</tt>' operand. If the <tt>store</tt> is marked as
4903 <tt>volatile</tt>, then the optimizer is not allowed to modify the number or
4904 order of execution of this <tt>store</tt> with other <a
4905 href="#volatile">volatile operations</a>.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4906
Eli Friedman21006d42011-08-09 23:02:53 +0000[diff] [blame]4907<p>If the <code>store</code> is marked as <code>atomic</code>, it takes an extra
4908 <a href="#ordering">ordering</a> and optional <code>singlethread</code>
4909 argument. The <code>acquire</code> and <code>acq_rel</code> orderings aren't
4910 valid on <code>store</code> instructions. Atomic loads produce <a
4911 href="#memorymodel">defined</a> results when they may see multiple atomic
4912 stores. The type of the pointee must be an integer type whose bit width
4913 is a power of two greater than or equal to eight and less than or equal
4914 to a target-specific size limit. <code>align</code> must be explicitly
4915 specified on atomic stores, and the store has undefined behavior if the
4916 alignment is not set to a value which is at least the size in bytes of
4917 the pointee. <code>!nontemporal</code> does not have any defined semantics
4918 for atomic stores.</p>
4919
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4920<p>The optional constant "align" argument specifies the alignment of the
4921 operation (that is, the alignment of the memory address). A value of 0 or an
4922 omitted "align" argument means that the operation has the preferential
4923 alignment for the target. It is the responsibility of the code emitter to
4924 ensure that the alignment information is correct. Overestimating the
4925 alignment results in an undefined behavior. Underestimating the alignment may
4926 produce less efficient code. An alignment of 1 is always safe.</p>
4927
David Greene8939b0d2010-02-16 20:50:18 +0000[diff] [blame]4928<p>The optional !nontemporal metadata must reference a single metatadata
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]4929 name &lt;index&gt; corresponding to a metadata node with one i32 entry of
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]4930 value 1. The existence of the !nontemporal metatadata on the
David Greene8939b0d2010-02-16 20:50:18 +0000[diff] [blame]4931 instruction tells the optimizer and code generator that this load is
4932 not expected to be reused in the cache. The code generator may
4933 select special instructions to save cache bandwidth, such as the
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]4934 MOVNT instruction on x86.</p>
David Greene8939b0d2010-02-16 20:50:18 +0000[diff] [blame]4935
4936
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4937<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4938<p>The contents of memory are updated to contain '<tt>&lt;value&gt;</tt>' at the
4939 location specified by the '<tt>&lt;pointer&gt;</tt>' operand. If
4940 '<tt>&lt;value&gt;</tt>' is of scalar type then the number of bytes written
4941 does not exceed the minimum number of bytes needed to hold all bits of the
4942 type. For example, storing an <tt>i24</tt> writes at most three bytes. When
4943 writing a value of a type like <tt>i20</tt> with a size that is not an
4944 integral number of bytes, it is unspecified what happens to the extra bits
4945 that do not belong to the type, but they will typically be overwritten.</p>
4946
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4947<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4948<pre>
4949 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Bill Wendling8c6c72d2007-10-22 05:10:05 +0000[diff] [blame]4950 store i32 3, i32* %ptr <i>; yields {void}</i>
4951 %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]4952</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4953
Reid Spencer47ce1792006-11-09 21:15:49 +0000[diff] [blame]4954</div>
4955
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4956<!-- _______________________________________________________________________ -->
NAKAMURA Takumib5bb29c2011-08-12 06:17:17 +0000[diff] [blame]4957<h4>
4958<a name="i_fence">'<tt>fence</tt>' Instruction</a>
4959</h4>
Eli Friedman47f35132011-07-25 23:16:38 +0000[diff] [blame]4960
NAKAMURA Takumib5bb29c2011-08-12 06:17:17 +0000[diff] [blame]4961<div>
Eli Friedman47f35132011-07-25 23:16:38 +0000[diff] [blame]4962
4963<h5>Syntax:</h5>
4964<pre>
4965 fence [singlethread] &lt;ordering&gt; <i>; yields {void}</i>
4966</pre>
4967
4968<h5>Overview:</h5>
4969<p>The '<tt>fence</tt>' instruction is used to introduce happens-before edges
4970between operations.</p>
4971
4972<h5>Arguments:</h5> <p>'<code>fence</code>' instructions take an <a
4973href="#ordering">ordering</a> argument which defines what
4974<i>synchronizes-with</i> edges they add. They can only be given
4975<code>acquire</code>, <code>release</code>, <code>acq_rel</code>, and
4976<code>seq_cst</code> orderings.</p>
4977
4978<h5>Semantics:</h5>
4979<p>A fence <var>A</var> which has (at least) <code>release</code> ordering
4980semantics <i>synchronizes with</i> a fence <var>B</var> with (at least)
4981<code>acquire</code> ordering semantics if and only if there exist atomic
4982operations <var>X</var> and <var>Y</var>, both operating on some atomic object
4983<var>M</var>, such that <var>A</var> is sequenced before <var>X</var>,
4984<var>X</var> modifies <var>M</var> (either directly or through some side effect
4985of a sequence headed by <var>X</var>), <var>Y</var> is sequenced before
4986<var>B</var>, and <var>Y</var> observes <var>M</var>. This provides a
4987<i>happens-before</i> dependency between <var>A</var> and <var>B</var>. Rather
4988than an explicit <code>fence</code>, one (but not both) of the atomic operations
4989<var>X</var> or <var>Y</var> might provide a <code>release</code> or
4990<code>acquire</code> (resp.) ordering constraint and still
4991<i>synchronize-with</i> the explicit <code>fence</code> and establish the
4992<i>happens-before</i> edge.</p>
4993
4994<p>A <code>fence</code> which has <code>seq_cst</code> ordering, in addition to
4995having both <code>acquire</code> and <code>release</code> semantics specified
4996above, participates in the global program order of other <code>seq_cst</code>
4997operations and/or fences.</p>
4998
4999<p>The optional "<a href="#singlethread"><code>singlethread</code></a>" argument
5000specifies that the fence only synchronizes with other fences in the same
5001thread. (This is useful for interacting with signal handlers.)</p>
5002
Eli Friedman47f35132011-07-25 23:16:38 +0000[diff] [blame]5003<h5>Example:</h5>
5004<pre>
5005 fence acquire <i>; yields {void}</i>
5006 fence singlethread seq_cst <i>; yields {void}</i>
5007</pre>
5008
5009</div>
5010
5011<!-- _______________________________________________________________________ -->
NAKAMURA Takumib5bb29c2011-08-12 06:17:17 +0000[diff] [blame]5012<h4>
5013<a name="i_cmpxchg">'<tt>cmpxchg</tt>' Instruction</a>
5014</h4>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]5015
NAKAMURA Takumib5bb29c2011-08-12 06:17:17 +0000[diff] [blame]5016<div>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]5017
5018<h5>Syntax:</h5>
5019<pre>
Bill Wendling262396b2011-12-09 22:41:40 +0000[diff] [blame]5020 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]5021</pre>
5022
5023<h5>Overview:</h5>
5024<p>The '<tt>cmpxchg</tt>' instruction is used to atomically modify memory.
5025It loads a value in memory and compares it to a given value. If they are
5026equal, it stores a new value into the memory.</p>
5027
5028<h5>Arguments:</h5>
5029<p>There are three arguments to the '<code>cmpxchg</code>' instruction: an
5030address to operate on, a value to compare to the value currently be at that
5031address, and a new value to place at that address if the compared values are
5032equal. The type of '<var>&lt;cmp&gt;</var>' must be an integer type whose
5033bit width is a power of two greater than or equal to eight and less than
5034or equal to a target-specific size limit. '<var>&lt;cmp&gt;</var>' and
5035'<var>&lt;new&gt;</var>' must have the same type, and the type of
5036'<var>&lt;pointer&gt;</var>' must be a pointer to that type. If the
5037<code>cmpxchg</code> is marked as <code>volatile</code>, then the
5038optimizer is not allowed to modify the number or order of execution
5039of this <code>cmpxchg</code> with other <a href="#volatile">volatile
5040operations</a>.</p>
5041
5042<!-- FIXME: Extend allowed types. -->
5043
5044<p>The <a href="#ordering"><var>ordering</var></a> argument specifies how this
5045<code>cmpxchg</code> synchronizes with other atomic operations.</p>
5046
5047<p>The optional "<code>singlethread</code>" argument declares that the
5048<code>cmpxchg</code> is only atomic with respect to code (usually signal
5049handlers) running in the same thread as the <code>cmpxchg</code>. Otherwise the
5050cmpxchg is atomic with respect to all other code in the system.</p>
5051
5052<p>The pointer passed into cmpxchg must have alignment greater than or equal to
5053the size in memory of the operand.
5054
5055<h5>Semantics:</h5>
5056<p>The contents of memory at the location specified by the
5057'<tt>&lt;pointer&gt;</tt>' operand is read and compared to
5058'<tt>&lt;cmp&gt;</tt>'; if the read value is the equal,
5059'<tt>&lt;new&gt;</tt>' is written. The original value at the location
5060is returned.
5061
5062<p>A successful <code>cmpxchg</code> is a read-modify-write instruction for the
5063purpose of identifying <a href="#release_sequence">release sequences</a>. A
5064failed <code>cmpxchg</code> is equivalent to an atomic load with an ordering
5065parameter determined by dropping any <code>release</code> part of the
5066<code>cmpxchg</code>'s ordering.</p>
5067
5068<!--
5069FIXME: Is compare_exchange_weak() necessary? (Consider after we've done
5070optimization work on ARM.)
5071
5072FIXME: Is a weaker ordering constraint on failure helpful in practice?
5073-->
5074
5075<h5>Example:</h5>
5076<pre>
5077entry:
Bill Wendling262396b2011-12-09 22:41:40 +0000[diff] [blame]5078 %orig = atomic <a href="#i_load">load</a> i32* %ptr unordered <i>; yields {i32}</i>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]5079 <a href="#i_br">br</a> label %loop
5080
5081loop:
5082 %cmp = <a href="#i_phi">phi</a> i32 [ %orig, %entry ], [%old, %loop]
5083 %squared = <a href="#i_mul">mul</a> i32 %cmp, %cmp
Bill Wendling262396b2011-12-09 22:41:40 +0000[diff] [blame]5084 %old = cmpxchg i32* %ptr, i32 %cmp, i32 %squared <i>; yields {i32}</i>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]5085 %success = <a href="#i_icmp">icmp</a> eq i32 %cmp, %old
5086 <a href="#i_br">br</a> i1 %success, label %done, label %loop
5087
5088done:
5089 ...
5090</pre>
5091
5092</div>
5093
5094<!-- _______________________________________________________________________ -->
NAKAMURA Takumib5bb29c2011-08-12 06:17:17 +0000[diff] [blame]5095<h4>
5096<a name="i_atomicrmw">'<tt>atomicrmw</tt>' Instruction</a>
5097</h4>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]5098
NAKAMURA Takumib5bb29c2011-08-12 06:17:17 +0000[diff] [blame]5099<div>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]5100
5101<h5>Syntax:</h5>
5102<pre>
Eli Friedmanf03bb262011-08-12 22:50:01 +0000[diff] [blame]5103 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]5104</pre>
5105
5106<h5>Overview:</h5>
5107<p>The '<tt>atomicrmw</tt>' instruction is used to atomically modify memory.</p>
5108
5109<h5>Arguments:</h5>
5110<p>There are three arguments to the '<code>atomicrmw</code>' instruction: an
5111operation to apply, an address whose value to modify, an argument to the
5112operation. The operation must be one of the following keywords:</p>
5113<ul>
5114 <li>xchg</li>
5115 <li>add</li>
5116 <li>sub</li>
5117 <li>and</li>
5118 <li>nand</li>
5119 <li>or</li>
5120 <li>xor</li>
5121 <li>max</li>
5122 <li>min</li>
5123 <li>umax</li>
5124 <li>umin</li>
5125</ul>
5126
5127<p>The type of '<var>&lt;value&gt;</var>' must be an integer type whose
5128bit width is a power of two greater than or equal to eight and less than
5129or equal to a target-specific size limit. The type of the
5130'<code>&lt;pointer&gt;</code>' operand must be a pointer to that type.
5131If the <code>atomicrmw</code> is marked as <code>volatile</code>, then the
5132optimizer is not allowed to modify the number or order of execution of this
5133<code>atomicrmw</code> with other <a href="#volatile">volatile
5134 operations</a>.</p>
5135
5136<!-- FIXME: Extend allowed types. -->
5137
5138<h5>Semantics:</h5>
5139<p>The contents of memory at the location specified by the
5140'<tt>&lt;pointer&gt;</tt>' operand are atomically read, modified, and written
5141back. The original value at the location is returned. The modification is
5142specified by the <var>operation</var> argument:</p>
5143
5144<ul>
5145 <li>xchg: <code>*ptr = val</code></li>
5146 <li>add: <code>*ptr = *ptr + val</code></li>
5147 <li>sub: <code>*ptr = *ptr - val</code></li>
5148 <li>and: <code>*ptr = *ptr &amp; val</code></li>
5149 <li>nand: <code>*ptr = ~(*ptr &amp; val)</code></li>
5150 <li>or: <code>*ptr = *ptr | val</code></li>
5151 <li>xor: <code>*ptr = *ptr ^ val</code></li>
5152 <li>max: <code>*ptr = *ptr &gt; val ? *ptr : val</code> (using a signed comparison)</li>
5153 <li>min: <code>*ptr = *ptr &lt; val ? *ptr : val</code> (using a signed comparison)</li>
5154 <li>umax: <code>*ptr = *ptr &gt; val ? *ptr : val</code> (using an unsigned comparison)</li>
5155 <li>umin: <code>*ptr = *ptr &lt; val ? *ptr : val</code> (using an unsigned comparison)</li>
5156</ul>
5157
5158<h5>Example:</h5>
5159<pre>
5160 %old = atomicrmw add i32* %ptr, i32 1 acquire <i>; yields {i32}</i>
5161</pre>
5162
5163</div>
5164
5165<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5166<h4>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5167 <a name="i_getelementptr">'<tt>getelementptr</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5168</h4>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5169
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5170<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5171
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]5172<h5>Syntax:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5173<pre>
Matthijs Kooijmane49d0bc2008-10-13 13:44:15 +0000[diff] [blame]5174 &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]5175 &lt;result&gt; = getelementptr inbounds &lt;pty&gt;* &lt;ptrval&gt;{, &lt;ty&gt; &lt;idx&gt;}*
Nadav Rotem16087692011-12-05 06:29:09 +0000[diff] [blame]5176 &lt;result&gt; = getelementptr &lt;ptr vector&gt; ptrval, &lt;vector index type&gt; idx
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5177</pre>
5178
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]5179<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5180<p>The '<tt>getelementptr</tt>' instruction is used to get the address of a
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]5181 subelement of an <a href="#t_aggregate">aggregate</a> data structure.
5182 It performs address calculation only and does not access memory.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5183
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]5184<h5>Arguments:</h5>
Nadav Rotem16087692011-12-05 06:29:09 +0000[diff] [blame]5185<p>The first argument is always a pointer or a vector of pointers,
5186 and forms the basis of the
Chris Lattnerc8eef442009-07-29 06:44:13 +0000[diff] [blame]5187 calculation. The remaining arguments are indices that indicate which of the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5188 elements of the aggregate object are indexed. The interpretation of each
5189 index is dependent on the type being indexed into. The first index always
5190 indexes the pointer value given as the first argument, the second index
5191 indexes a value of the type pointed to (not necessarily the value directly
5192 pointed to, since the first index can be non-zero), etc. The first type
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]5193 indexed into must be a pointer value, subsequent types can be arrays,
Chris Lattner61c70e92010-08-28 04:09:24 +0000[diff] [blame]5194 vectors, and structs. Note that subsequent types being indexed into
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]5195 can never be pointers, since that would require loading the pointer before
5196 continuing calculation.</p>
Matthijs Kooijmane49d0bc2008-10-13 13:44:15 +0000[diff] [blame]5197
5198<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]5199 When indexing into a (optionally packed) structure, only <tt>i32</tt>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]5200 integer <b>constants</b> are allowed. When indexing into an array, pointer
5201 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]5202 constant. These integers are treated as signed values where relevant.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5203
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5204<p>For example, let's consider a C code fragment and how it gets compiled to
5205 LLVM:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5206
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]5207<pre class="doc_code">
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]5208struct RT {
5209 char A;
Chris Lattnercabc8462007-05-29 15:43:56 +0000[diff] [blame]5210 int B[10][20];
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]5211 char C;
5212};
5213struct ST {
Chris Lattnercabc8462007-05-29 15:43:56 +0000[diff] [blame]5214 int X;
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]5215 double Y;
5216 struct RT Z;
5217};
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5218
Chris Lattnercabc8462007-05-29 15:43:56 +0000[diff] [blame]5219int *foo(struct ST *s) {
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]5220 return &amp;s[1].Z.B[5][13];
5221}
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5222</pre>
5223
Bill Wendlinga3495392011-12-13 01:07:07 +0000[diff] [blame]5224<p>The LLVM code generated by Clang is:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5225
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]5226<pre class="doc_code">
Bill Wendlinga3495392011-12-13 01:07:07 +0000[diff] [blame]5227%struct.RT = <a href="#namedtypes">type</a> { i8, [10 x [20 x i32]], i8 }
5228%struct.ST = <a href="#namedtypes">type</a> { i32, double, %struct.RT }
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5229
Bill Wendlinga3495392011-12-13 01:07:07 +0000[diff] [blame]5230define i32* @foo(%struct.ST* %s) nounwind uwtable readnone optsize ssp {
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]5231entry:
Bill Wendlinga3495392011-12-13 01:07:07 +0000[diff] [blame]5232 %arrayidx = getelementptr inbounds %struct.ST* %s, i64 1, i32 2, i32 1, i64 5, i64 13
5233 ret i32* %arrayidx
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]5234}
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5235</pre>
5236
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]5237<h5>Semantics:</h5>
Bill Wendlinga3495392011-12-13 01:07:07 +0000[diff] [blame]5238<p>In the example above, the first index is indexing into the
5239 '<tt>%struct.ST*</tt>' type, which is a pointer, yielding a
5240 '<tt>%struct.ST</tt>' = '<tt>{ i32, double, %struct.RT }</tt>' type, a
5241 structure. The second index indexes into the third element of the structure,
5242 yielding a '<tt>%struct.RT</tt>' = '<tt>{ i8 , [10 x [20 x i32]], i8 }</tt>'
5243 type, another structure. The third index indexes into the second element of
5244 the structure, yielding a '<tt>[10 x [20 x i32]]</tt>' type, an array. The
5245 two dimensions of the array are subscripted into, yielding an '<tt>i32</tt>'
5246 type. The '<tt>getelementptr</tt>' instruction returns a pointer to this
5247 element, thus computing a value of '<tt>i32*</tt>' type.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5248
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5249<p>Note that it is perfectly legal to index partially through a structure,
5250 returning a pointer to an inner element. Because of this, the LLVM code for
5251 the given testcase is equivalent to:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5252
Bill Wendlinga3495392011-12-13 01:07:07 +0000[diff] [blame]5253<pre class="doc_code">
5254define i32* @foo(%struct.ST* %s) {
5255 %t1 = getelementptr %struct.ST* %s, i32 1 <i>; yields %struct.ST*:%t1</i>
5256 %t2 = getelementptr %struct.ST* %t1, i32 0, i32 2 <i>; yields %struct.RT*:%t2</i>
5257 %t3 = getelementptr %struct.RT* %t2, i32 0, i32 1 <i>; yields [10 x [20 x i32]]*:%t3</i>
5258 %t4 = getelementptr [10 x [20 x i32]]* %t3, i32 0, i32 5 <i>; yields [20 x i32]*:%t4</i>
5259 %t5 = getelementptr [20 x i32]* %t4, i32 0, i32 13 <i>; yields i32*:%t5</i>
5260 ret i32* %t5
5261}
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]5262</pre>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]5263
Dan Gohmandd8004d2009-07-27 21:53:46 +0000[diff] [blame]5264<p>If the <tt>inbounds</tt> keyword is present, the result value of the
Dan Gohmanbfb056d2011-12-06 03:18:47 +0000[diff] [blame]5265 <tt>getelementptr</tt> is a <a href="#poisonvalues">poison value</a> if the
Dan Gohman27ef9972010-04-23 15:23:32 +0000[diff] [blame]5266 base pointer is not an <i>in bounds</i> address of an allocated object,
5267 or if any of the addresses that would be formed by successive addition of
5268 the offsets implied by the indices to the base address with infinitely
Eli Friedman266246c2011-08-12 23:37:55 +0000[diff] [blame]5269 precise signed arithmetic are not an <i>in bounds</i> address of that
5270 allocated object. The <i>in bounds</i> addresses for an allocated object
5271 are all the addresses that point into the object, plus the address one
Nadav Rotem16087692011-12-05 06:29:09 +0000[diff] [blame]5272 byte past the end.
5273 In cases where the base is a vector of pointers the <tt>inbounds</tt> keyword
5274 applies to each of the computations element-wise. </p>
Dan Gohmandd8004d2009-07-27 21:53:46 +0000[diff] [blame]5275
5276<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]5277 the base address with silently-wrapping two's complement arithmetic. If the
5278 offsets have a different width from the pointer, they are sign-extended or
5279 truncated to the width of the pointer. The result value of the
5280 <tt>getelementptr</tt> may be outside the object pointed to by the base
5281 pointer. The result value may not necessarily be used to access memory
5282 though, even if it happens to point into allocated storage. See the
5283 <a href="#pointeraliasing">Pointer Aliasing Rules</a> section for more
5284 information.</p>
Dan Gohmandd8004d2009-07-27 21:53:46 +0000[diff] [blame]5285
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5286<p>The getelementptr instruction is often confusing. For some more insight into
5287 how it works, see <a href="GetElementPtr.html">the getelementptr FAQ</a>.</p>
Chris Lattner884a9702006-08-15 00:45:58 +0000[diff] [blame]5288
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]5289<h5>Example:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5290<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5291 <i>; yields [12 x i8]*:aptr</i>
Matthijs Kooijmane49d0bc2008-10-13 13:44:15 +0000[diff] [blame]5292 %aptr = getelementptr {i32, [12 x i8]}* %saptr, i64 0, i32 1
5293 <i>; yields i8*:vptr</i>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]5294 %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]5295 <i>; yields i8*:eptr</i>
5296 %eptr = getelementptr [12 x i8]* %aptr, i64 0, i32 1
Sanjiv Gupta9f805c22009-04-25 07:27:44 +0000[diff] [blame]5297 <i>; yields i32*:iptr</i>
Sanjiv Gupta16ffa802009-04-24 16:38:13 +0000[diff] [blame]5298 %iptr = getelementptr [10 x i32]* @arr, i16 0, i16 0
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5299</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5300
Nadav Rotem16087692011-12-05 06:29:09 +0000[diff] [blame]5301<p>In cases where the pointer argument is a vector of pointers, only a
5302 single index may be used, and the number of vector elements has to be
5303 the same. For example: </p>
5304<pre class="doc_code">
5305 %A = getelementptr <4 x i8*> %ptrs, <4 x i64> %offsets,
5306</pre>
5307
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5308</div>
Reid Spencer47ce1792006-11-09 21:15:49 +0000[diff] [blame]5309
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5310</div>
5311
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]5312<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5313<h3>
5314 <a name="convertops">Conversion Operations</a>
5315</h3>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5316
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5317<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5318
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5319<p>The instructions in this category are the conversion instructions (casting)
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5320 which all take a single operand and a type. They perform various bit
5321 conversions on the operand.</p>
5322
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]5323<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5324<h4>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5325 <a name="i_trunc">'<tt>trunc .. to</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5326</h4>
5327
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5328<div>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5329
5330<h5>Syntax:</h5>
5331<pre>
5332 &lt;result&gt; = trunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
5333</pre>
5334
5335<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5336<p>The '<tt>trunc</tt>' instruction truncates its operand to the
5337 type <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5338
5339<h5>Arguments:</h5>
Nadav Rotem8c20ec52011-02-24 21:01:34 +0000[diff] [blame]5340<p>The '<tt>trunc</tt>' instruction takes a value to trunc, and a type to trunc it to.
5341 Both types must be of <a href="#t_integer">integer</a> types, or vectors
5342 of the same number of integers.
5343 The bit size of the <tt>value</tt> must be larger than
5344 the bit size of the destination type, <tt>ty2</tt>.
5345 Equal sized types are not allowed.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5346
5347<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5348<p>The '<tt>trunc</tt>' instruction truncates the high order bits
5349 in <tt>value</tt> and converts the remaining bits to <tt>ty2</tt>. Since the
5350 source size must be larger than the destination size, <tt>trunc</tt> cannot
5351 be a <i>no-op cast</i>. It will always truncate bits.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5352
5353<h5>Example:</h5>
5354<pre>
Nadav Rotem8c20ec52011-02-24 21:01:34 +0000[diff] [blame]5355 %X = trunc i32 257 to i8 <i>; yields i8:1</i>
5356 %Y = trunc i32 123 to i1 <i>; yields i1:true</i>
5357 %Z = trunc i32 122 to i1 <i>; yields i1:false</i>
5358 %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]5359</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5360
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5361</div>
5362
5363<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5364<h4>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5365 <a name="i_zext">'<tt>zext .. to</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5366</h4>
5367
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5368<div>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5369
5370<h5>Syntax:</h5>
5371<pre>
5372 &lt;result&gt; = zext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
5373</pre>
5374
5375<h5>Overview:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5376<p>The '<tt>zext</tt>' instruction zero extends its operand to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5377 <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5378
5379
5380<h5>Arguments:</h5>
Nadav Rotemed9b9342011-02-20 12:37:50 +0000[diff] [blame]5381<p>The '<tt>zext</tt>' instruction takes a value to cast, and a type to cast it to.
5382 Both types must be of <a href="#t_integer">integer</a> types, or vectors
5383 of the same number of integers.
5384 The bit size of the <tt>value</tt> must be smaller than
5385 the bit size of the destination type,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5386 <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5387
5388<h5>Semantics:</h5>
5389<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]5390 bits until it reaches the size of the destination type, <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5391
Reid Spencerb5929522007-01-12 15:46:11 +0000[diff] [blame]5392<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]5393
5394<h5>Example:</h5>
5395<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5396 %X = zext i32 257 to i64 <i>; yields i64:257</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]5397 %Y = zext i1 true to i32 <i>; yields i32:1</i>
Nadav Rotemed9b9342011-02-20 12:37:50 +0000[diff] [blame]5398 %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]5399</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5400
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5401</div>
5402
5403<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5404<h4>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5405 <a name="i_sext">'<tt>sext .. to</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5406</h4>
5407
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5408<div>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5409
5410<h5>Syntax:</h5>
5411<pre>
5412 &lt;result&gt; = sext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
5413</pre>
5414
5415<h5>Overview:</h5>
5416<p>The '<tt>sext</tt>' sign extends <tt>value</tt> to the type <tt>ty2</tt>.</p>
5417
5418<h5>Arguments:</h5>
Nadav Rotem8c20ec52011-02-24 21:01:34 +0000[diff] [blame]5419<p>The '<tt>sext</tt>' instruction takes a value to cast, and a type to cast it to.
5420 Both types must be of <a href="#t_integer">integer</a> types, or vectors
5421 of the same number of integers.
5422 The bit size of the <tt>value</tt> must be smaller than
5423 the bit size of the destination type,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5424 <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5425
5426<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5427<p>The '<tt>sext</tt>' instruction performs a sign extension by copying the sign
5428 bit (highest order bit) of the <tt>value</tt> until it reaches the bit size
5429 of the type <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5430
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]5431<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]5432
5433<h5>Example:</h5>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5434<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5435 %X = sext i8 -1 to i16 <i>; yields i16 :65535</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]5436 %Y = sext i1 true to i32 <i>; yields i32:-1</i>
Nadav Rotem8c20ec52011-02-24 21:01:34 +0000[diff] [blame]5437 %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]5438</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5439
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5440</div>
5441
5442<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5443<h4>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]5444 <a name="i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5445</h4>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]5446
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5447<div>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]5448
5449<h5>Syntax:</h5>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]5450<pre>
5451 &lt;result&gt; = fptrunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
5452</pre>
5453
5454<h5>Overview:</h5>
5455<p>The '<tt>fptrunc</tt>' instruction truncates <tt>value</tt> to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5456 <tt>ty2</tt>.</p>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]5457
5458<h5>Arguments:</h5>
5459<p>The '<tt>fptrunc</tt>' instruction takes a <a href="#t_floating">floating
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5460 point</a> value to cast and a <a href="#t_floating">floating point</a> type
5461 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]5462 <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]5463 <i>no-op cast</i>.</p>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]5464
5465<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5466<p>The '<tt>fptrunc</tt>' instruction truncates a <tt>value</tt> from a larger
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5467 <a href="#t_floating">floating point</a> type to a smaller
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5468 <a href="#t_floating">floating point</a> type. If the value cannot fit
5469 within the destination type, <tt>ty2</tt>, then the results are
5470 undefined.</p>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]5471
5472<h5>Example:</h5>
5473<pre>
5474 %X = fptrunc double 123.0 to float <i>; yields float:123.0</i>
5475 %Y = fptrunc double 1.0E+300 to float <i>; yields undefined</i>
5476</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5477
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]5478</div>
5479
5480<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5481<h4>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5482 <a name="i_fpext">'<tt>fpext .. to</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5483</h4>
5484
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5485<div>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5486
5487<h5>Syntax:</h5>
5488<pre>
5489 &lt;result&gt; = fpext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
5490</pre>
5491
5492<h5>Overview:</h5>
5493<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]5494 floating point value.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5495
5496<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5497<p>The '<tt>fpext</tt>' instruction takes a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5498 <a href="#t_floating">floating point</a> <tt>value</tt> to cast, and
5499 a <a href="#t_floating">floating point</a> type to cast it to. The source
5500 type must be smaller than the destination type.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5501
5502<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]5503<p>The '<tt>fpext</tt>' instruction extends the <tt>value</tt> from a smaller
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5504 <a href="#t_floating">floating point</a> type to a larger
5505 <a href="#t_floating">floating point</a> type. The <tt>fpext</tt> cannot be
5506 used to make a <i>no-op cast</i> because it always changes bits. Use
5507 <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]5508
5509<h5>Example:</h5>
5510<pre>
Nick Lewycky5bb3ece2011-03-31 18:20:19 +0000[diff] [blame]5511 %X = fpext float 3.125 to double <i>; yields double:3.125000e+00</i>
5512 %Y = fpext double %X to fp128 <i>; yields fp128:0xL00000000000000004000900000000000</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5513</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5514
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5515</div>
5516
5517<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5518<h4>
Reid Spencer24d6da52007-01-21 00:29:26 +0000[diff] [blame]5519 <a name="i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5520</h4>
5521
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5522<div>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5523
5524<h5>Syntax:</h5>
5525<pre>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]5526 &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]5527</pre>
5528
5529<h5>Overview:</h5>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]5530<p>The '<tt>fptoui</tt>' converts a floating point <tt>value</tt> to its
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5531 unsigned integer equivalent of type <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5532
5533<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5534<p>The '<tt>fptoui</tt>' instruction takes a value to cast, which must be a
5535 scalar or vector <a href="#t_floating">floating point</a> value, and a type
5536 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
5537 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
5538 vector integer type with the same number of elements as <tt>ty</tt></p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5539
5540<h5>Semantics:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5541<p>The '<tt>fptoui</tt>' instruction converts its
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5542 <a href="#t_floating">floating point</a> operand into the nearest (rounding
5543 towards zero) unsigned integer value. If the value cannot fit
5544 in <tt>ty2</tt>, the results are undefined.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5545
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5546<h5>Example:</h5>
5547<pre>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]5548 %X = fptoui double 123.0 to i32 <i>; yields i32:123</i>
Chris Lattner88519042007-09-22 03:17:52 +0000[diff] [blame]5549 %Y = fptoui float 1.0E+300 to i1 <i>; yields undefined:1</i>
Gabor Greif6a292012009-10-28 09:21:30 +0000[diff] [blame]5550 %Z = fptoui float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5551</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5552
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5553</div>
5554
5555<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5556<h4>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]5557 <a name="i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5558</h4>
5559
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5560<div>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5561
5562<h5>Syntax:</h5>
5563<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]5564 &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]5565</pre>
5566
5567<h5>Overview:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5568<p>The '<tt>fptosi</tt>' instruction converts
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5569 <a href="#t_floating">floating point</a> <tt>value</tt> to
5570 type <tt>ty2</tt>.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5571
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]5572<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5573<p>The '<tt>fptosi</tt>' instruction takes a value to cast, which must be a
5574 scalar or vector <a href="#t_floating">floating point</a> value, and a type
5575 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
5576 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
5577 vector integer type with the same number of elements as <tt>ty</tt></p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5578
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]5579<h5>Semantics:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5580<p>The '<tt>fptosi</tt>' instruction converts its
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5581 <a href="#t_floating">floating point</a> operand into the nearest (rounding
5582 towards zero) signed integer value. If the value cannot fit in <tt>ty2</tt>,
5583 the results are undefined.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5584
Chris Lattner33ba0d92001-07-09 00:26:23 +0000[diff] [blame]5585<h5>Example:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5586<pre>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]5587 %X = fptosi double -123.0 to i32 <i>; yields i32:-123</i>
Chris Lattner88519042007-09-22 03:17:52 +0000[diff] [blame]5588 %Y = fptosi float 1.0E-247 to i1 <i>; yields undefined:1</i>
Gabor Greif6a292012009-10-28 09:21:30 +0000[diff] [blame]5589 %Z = fptosi float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5590</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5591
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5592</div>
5593
5594<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5595<h4>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]5596 <a name="i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5597</h4>
5598
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5599<div>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5600
5601<h5>Syntax:</h5>
5602<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]5603 &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]5604</pre>
5605
5606<h5>Overview:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]5607<p>The '<tt>uitofp</tt>' instruction regards <tt>value</tt> as an unsigned
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5608 integer and converts that value to the <tt>ty2</tt> type.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5609
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5610<h5>Arguments:</h5>
Nate Begemanb348d182007-11-17 03:58:34 +0000[diff] [blame]5611<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]5612 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
5613 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
5614 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
5615 floating point type with the same number of elements as <tt>ty</tt></p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5616
5617<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]5618<p>The '<tt>uitofp</tt>' instruction interprets its operand as an unsigned
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5619 integer quantity and converts it to the corresponding floating point
5620 value. If the value cannot fit in the floating point value, the results are
5621 undefined.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5622
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5623<h5>Example:</h5>
5624<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5625 %X = uitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]5626 %Y = uitofp i8 -1 to double <i>; yields double:255.0</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5627</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5628
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5629</div>
5630
5631<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5632<h4>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]5633 <a name="i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5634</h4>
5635
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5636<div>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5637
5638<h5>Syntax:</h5>
5639<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]5640 &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]5641</pre>
5642
5643<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5644<p>The '<tt>sitofp</tt>' instruction regards <tt>value</tt> as a signed integer
5645 and converts that value to the <tt>ty2</tt> type.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5646
5647<h5>Arguments:</h5>
Nate Begemanb348d182007-11-17 03:58:34 +0000[diff] [blame]5648<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]5649 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
5650 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
5651 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
5652 floating point type with the same number of elements as <tt>ty</tt></p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5653
5654<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5655<p>The '<tt>sitofp</tt>' instruction interprets its operand as a signed integer
5656 quantity and converts it to the corresponding floating point value. If the
5657 value cannot fit in the floating point value, the results are undefined.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5658
5659<h5>Example:</h5>
5660<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5661 %X = sitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]5662 %Y = sitofp i8 -1 to double <i>; yields double:-1.0</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5663</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5664
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5665</div>
5666
5667<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5668<h4>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]5669 <a name="i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5670</h4>
5671
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5672<div>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]5673
5674<h5>Syntax:</h5>
5675<pre>
5676 &lt;result&gt; = ptrtoint &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
5677</pre>
5678
5679<h5>Overview:</h5>
Nadav Rotem16087692011-12-05 06:29:09 +0000[diff] [blame]5680<p>The '<tt>ptrtoint</tt>' instruction converts the pointer or a vector of
5681 pointers <tt>value</tt> to
5682 the integer (or vector of integers) type <tt>ty2</tt>.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]5683
5684<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5685<p>The '<tt>ptrtoint</tt>' instruction takes a <tt>value</tt> to cast, which
Nadav Rotem16087692011-12-05 06:29:09 +0000[diff] [blame]5686 must be a a value of type <a href="#t_pointer">pointer</a> or a vector of
5687 pointers, and a type to cast it to
5688 <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a> or a vector
5689 of integers type.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]5690
5691<h5>Semantics:</h5>
5692<p>The '<tt>ptrtoint</tt>' instruction converts <tt>value</tt> to integer type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5693 <tt>ty2</tt> by interpreting the pointer value as an integer and either
5694 truncating or zero extending that value to the size of the integer type. If
5695 <tt>value</tt> is smaller than <tt>ty2</tt> then a zero extension is done. If
5696 <tt>value</tt> is larger than <tt>ty2</tt> then a truncation is done. If they
5697 are the same size, then nothing is done (<i>no-op cast</i>) other than a type
5698 change.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]5699
5700<h5>Example:</h5>
5701<pre>
Nadav Rotem16087692011-12-05 06:29:09 +0000[diff] [blame]5702 %X = ptrtoint i32* %P to i8 <i>; yields truncation on 32-bit architecture</i>
5703 %Y = ptrtoint i32* %P to i64 <i>; yields zero extension on 32-bit architecture</i>
5704 %Z = ptrtoint &lt;4 x i32*&gt; %P to &lt;4 x i64&gt;<i>; yields vector zero extension for a vector of addresses on 32-bit architecture</i>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]5705</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5706
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]5707</div>
5708
5709<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5710<h4>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]5711 <a name="i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5712</h4>
5713
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5714<div>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]5715
5716<h5>Syntax:</h5>
5717<pre>
5718 &lt;result&gt; = inttoptr &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
5719</pre>
5720
5721<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5722<p>The '<tt>inttoptr</tt>' instruction converts an integer <tt>value</tt> to a
5723 pointer type, <tt>ty2</tt>.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]5724
5725<h5>Arguments:</h5>
Duncan Sands8036ca42007-03-30 12:22:09 +0000[diff] [blame]5726<p>The '<tt>inttoptr</tt>' instruction takes an <a href="#t_integer">integer</a>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5727 value to cast, and a type to cast it to, which must be a
5728 <a href="#t_pointer">pointer</a> type.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]5729
5730<h5>Semantics:</h5>
5731<p>The '<tt>inttoptr</tt>' instruction converts <tt>value</tt> to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5732 <tt>ty2</tt> by applying either a zero extension or a truncation depending on
5733 the size of the integer <tt>value</tt>. If <tt>value</tt> is larger than the
5734 size of a pointer then a truncation is done. If <tt>value</tt> is smaller
5735 than the size of a pointer then a zero extension is done. If they are the
5736 same size, nothing is done (<i>no-op cast</i>).</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]5737
5738<h5>Example:</h5>
5739<pre>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5740 %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]5741 %Y = inttoptr i32 255 to i32* <i>; yields no-op on 32-bit architecture</i>
5742 %Z = inttoptr i64 0 to i32* <i>; yields truncation on 32-bit architecture</i>
Nadav Rotem16087692011-12-05 06:29:09 +0000[diff] [blame]5743 %Z = inttoptr &lt;4 x i32&gt; %G to &lt;4 x i8*&gt;<i>; yields truncation of vector G to four pointers</i>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]5744</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5745
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]5746</div>
5747
5748<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5749<h4>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]5750 <a name="i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5751</h4>
5752
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5753<div>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5754
5755<h5>Syntax:</h5>
5756<pre>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]5757 &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]5758</pre>
5759
5760<h5>Overview:</h5>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]5761<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5762 <tt>ty2</tt> without changing any bits.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5763
5764<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5765<p>The '<tt>bitcast</tt>' instruction takes a value to cast, which must be a
5766 non-aggregate first class value, and a type to cast it to, which must also be
5767 a non-aggregate <a href="#t_firstclass">first class</a> type. The bit sizes
5768 of <tt>value</tt> and the destination type, <tt>ty2</tt>, must be
5769 identical. If the source type is a pointer, the destination type must also be
5770 a pointer. This instruction supports bitwise conversion of vectors to
5771 integers and to vectors of other types (as long as they have the same
5772 size).</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5773
5774<h5>Semantics:</h5>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]5775<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5776 <tt>ty2</tt>. It is always a <i>no-op cast</i> because no bits change with
5777 this conversion. The conversion is done as if the <tt>value</tt> had been
Nadav Rotem16087692011-12-05 06:29:09 +0000[diff] [blame]5778 stored to memory and read back as type <tt>ty2</tt>.
5779 Pointer (or vector of pointers) types may only be converted to other pointer
5780 (or vector of pointers) types with this instruction. To convert
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5781 pointers to other types, use the <a href="#i_inttoptr">inttoptr</a> or
5782 <a href="#i_ptrtoint">ptrtoint</a> instructions first.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5783
5784<h5>Example:</h5>
5785<pre>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5786 %X = bitcast i8 255 to i8 <i>; yields i8 :-1</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5787 %Y = bitcast i32* %x to sint* <i>; yields sint*:%x</i>
Nadav Rotem16087692011-12-05 06:29:09 +0000[diff] [blame]5788 %Z = bitcast &lt;2 x int&gt; %V to i64; <i>; yields i64: %V</i>
5789 %Z = bitcast &lt;2 x i32*&gt; %V to &lt;2 x i64*&gt; <i>; yields &lt;2 x i64*&gt;</i>
Chris Lattner33ba0d92001-07-09 00:26:23 +0000[diff] [blame]5790</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5791
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5792</div>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5793
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5794</div>
5795
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5796<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5797<h3>
5798 <a name="otherops">Other Operations</a>
5799</h3>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5800
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5801<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5802
5803<p>The instructions in this category are the "miscellaneous" instructions, which
5804 defy better classification.</p>
5805
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5806<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5807<h4>
5808 <a name="i_icmp">'<tt>icmp</tt>' Instruction</a>
5809</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5810
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5811<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5812
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5813<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5814<pre>
5815 &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]5816</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5817
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5818<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5819<p>The '<tt>icmp</tt>' instruction returns a boolean value or a vector of
Nadav Rotem16087692011-12-05 06:29:09 +0000[diff] [blame]5820 boolean values based on comparison of its two integer, integer vector,
5821 pointer, or pointer vector operands.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5822
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5823<h5>Arguments:</h5>
5824<p>The '<tt>icmp</tt>' instruction takes three operands. The first operand is
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5825 the condition code indicating the kind of comparison to perform. It is not a
5826 value, just a keyword. The possible condition code are:</p>
5827
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5828<ol>
5829 <li><tt>eq</tt>: equal</li>
5830 <li><tt>ne</tt>: not equal </li>
5831 <li><tt>ugt</tt>: unsigned greater than</li>
5832 <li><tt>uge</tt>: unsigned greater or equal</li>
5833 <li><tt>ult</tt>: unsigned less than</li>
5834 <li><tt>ule</tt>: unsigned less or equal</li>
5835 <li><tt>sgt</tt>: signed greater than</li>
5836 <li><tt>sge</tt>: signed greater or equal</li>
5837 <li><tt>slt</tt>: signed less than</li>
5838 <li><tt>sle</tt>: signed less or equal</li>
5839</ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5840
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]5841<p>The remaining two arguments must be <a href="#t_integer">integer</a> or
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5842 <a href="#t_pointer">pointer</a> or integer <a href="#t_vector">vector</a>
5843 typed. They must also be identical types.</p>
5844
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5845<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5846<p>The '<tt>icmp</tt>' compares <tt>op1</tt> and <tt>op2</tt> according to the
5847 condition code given as <tt>cond</tt>. The comparison performed always yields
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]5848 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]5849 result, as follows:</p>
5850
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5851<ol>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5852 <li><tt>eq</tt>: yields <tt>true</tt> if the operands are equal,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5853 <tt>false</tt> otherwise. No sign interpretation is necessary or
5854 performed.</li>
5855
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5856 <li><tt>ne</tt>: yields <tt>true</tt> if the operands are unequal,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5857 <tt>false</tt> otherwise. No sign interpretation is necessary or
5858 performed.</li>
5859
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5860 <li><tt>ugt</tt>: interprets the operands as unsigned values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5861 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
5862
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5863 <li><tt>uge</tt>: interprets the operands as unsigned values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5864 <tt>true</tt> if <tt>op1</tt> is greater than or equal
5865 to <tt>op2</tt>.</li>
5866
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5867 <li><tt>ult</tt>: interprets the operands as unsigned values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5868 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
5869
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5870 <li><tt>ule</tt>: interprets the operands as unsigned values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5871 <tt>true</tt> if <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
5872
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5873 <li><tt>sgt</tt>: interprets the operands as signed values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5874 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
5875
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5876 <li><tt>sge</tt>: interprets the operands as signed values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5877 <tt>true</tt> if <tt>op1</tt> is greater than or equal
5878 to <tt>op2</tt>.</li>
5879
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5880 <li><tt>slt</tt>: interprets the operands as signed values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5881 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
5882
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5883 <li><tt>sle</tt>: interprets the operands as signed values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5884 <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]5885</ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5886
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5887<p>If the operands are <a href="#t_pointer">pointer</a> typed, the pointer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5888 values are compared as if they were integers.</p>
5889
5890<p>If the operands are integer vectors, then they are compared element by
5891 element. The result is an <tt>i1</tt> vector with the same number of elements
5892 as the values being compared. Otherwise, the result is an <tt>i1</tt>.</p>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5893
5894<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5895<pre>
5896 &lt;result&gt; = icmp eq i32 4, 5 <i>; yields: result=false</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5897 &lt;result&gt; = icmp ne float* %X, %X <i>; yields: result=false</i>
5898 &lt;result&gt; = icmp ult i16 4, 5 <i>; yields: result=true</i>
5899 &lt;result&gt; = icmp sgt i16 4, 5 <i>; yields: result=false</i>
5900 &lt;result&gt; = icmp ule i16 -4, 5 <i>; yields: result=false</i>
5901 &lt;result&gt; = icmp sge i16 4, 5 <i>; yields: result=false</i>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5902</pre>
Dan Gohmanc766f722009-01-22 01:39:38 +0000[diff] [blame]5903
5904<p>Note that the code generator does not yet support vector types with
5905 the <tt>icmp</tt> instruction.</p>
5906
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5907</div>
5908
5909<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5910<h4>
5911 <a name="i_fcmp">'<tt>fcmp</tt>' Instruction</a>
5912</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5913
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5914<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5915
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5916<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5917<pre>
5918 &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]5919</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5920
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5921<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5922<p>The '<tt>fcmp</tt>' instruction returns a boolean value or vector of boolean
5923 values based on comparison of its operands.</p>
5924
5925<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]5926(<a href="#t_integer"><tt>i1</tt></a>).</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5927
5928<p>If the operands are floating point vectors, then the result type is a vector
5929 of boolean with the same number of elements as the operands being
5930 compared.</p>
5931
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5932<h5>Arguments:</h5>
5933<p>The '<tt>fcmp</tt>' instruction takes three operands. The first operand is
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5934 the condition code indicating the kind of comparison to perform. It is not a
5935 value, just a keyword. The possible condition code are:</p>
5936
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5937<ol>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]5938 <li><tt>false</tt>: no comparison, always returns false</li>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5939 <li><tt>oeq</tt>: ordered and equal</li>
5940 <li><tt>ogt</tt>: ordered and greater than </li>
5941 <li><tt>oge</tt>: ordered and greater than or equal</li>
5942 <li><tt>olt</tt>: ordered and less than </li>
5943 <li><tt>ole</tt>: ordered and less than or equal</li>
5944 <li><tt>one</tt>: ordered and not equal</li>
5945 <li><tt>ord</tt>: ordered (no nans)</li>
5946 <li><tt>ueq</tt>: unordered or equal</li>
5947 <li><tt>ugt</tt>: unordered or greater than </li>
5948 <li><tt>uge</tt>: unordered or greater than or equal</li>
5949 <li><tt>ult</tt>: unordered or less than </li>
5950 <li><tt>ule</tt>: unordered or less than or equal</li>
5951 <li><tt>une</tt>: unordered or not equal</li>
5952 <li><tt>uno</tt>: unordered (either nans)</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]5953 <li><tt>true</tt>: no comparison, always returns true</li>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5954</ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5955
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5956<p><i>Ordered</i> means that neither operand is a QNAN while
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5957 <i>unordered</i> means that either operand may be a QNAN.</p>
5958
5959<p>Each of <tt>val1</tt> and <tt>val2</tt> arguments must be either
5960 a <a href="#t_floating">floating point</a> type or
5961 a <a href="#t_vector">vector</a> of floating point type. They must have
5962 identical types.</p>
5963
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5964<h5>Semantics:</h5>
Gabor Greiffb224a22008-08-07 21:46:00 +0000[diff] [blame]5965<p>The '<tt>fcmp</tt>' instruction compares <tt>op1</tt> and <tt>op2</tt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5966 according to the condition code given as <tt>cond</tt>. If the operands are
5967 vectors, then the vectors are compared element by element. Each comparison
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]5968 performed always yields an <a href="#t_integer">i1</a> result, as
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5969 follows:</p>
5970
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5971<ol>
5972 <li><tt>false</tt>: always yields <tt>false</tt>, regardless of operands.</li>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5973
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5974 <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]5975 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
5976
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]5977 <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]5978 <tt>op1</tt> is greater than <tt>op2</tt>.</li>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5979
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5980 <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]5981 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
5982
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5983 <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]5984 <tt>op1</tt> is less than <tt>op2</tt>.</li>
5985
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5986 <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]5987 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
5988
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5989 <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]5990 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
5991
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]5992 <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]5993
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5994 <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]5995 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
5996
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5997 <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]5998 <tt>op1</tt> is greater than <tt>op2</tt>.</li>
5999
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]6000 <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]6001 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
6002
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]6003 <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]6004 <tt>op1</tt> is less than <tt>op2</tt>.</li>
6005
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]6006 <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]6007 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
6008
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]6009 <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]6010 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
6011
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]6012 <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]6013
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]6014 <li><tt>true</tt>: always yields <tt>true</tt>, regardless of operands.</li>
6015</ol>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]6016
6017<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6018<pre>
6019 &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]6020 &lt;result&gt; = fcmp one float 4.0, 5.0 <i>; yields: result=true</i>
6021 &lt;result&gt; = fcmp olt float 4.0, 5.0 <i>; yields: result=true</i>
6022 &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]6023</pre>
Dan Gohmanc766f722009-01-22 01:39:38 +0000[diff] [blame]6024
6025<p>Note that the code generator does not yet support vector types with
6026 the <tt>fcmp</tt> instruction.</p>
6027
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]6028</div>
6029
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]6030<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6031<h4>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]6032 <a name="i_phi">'<tt>phi</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6033</h4>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]6034
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6035<div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]6036
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]6037<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6038<pre>
6039 &lt;result&gt; = phi &lt;ty&gt; [ &lt;val0&gt;, &lt;label0&gt;], ...
6040</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]6041
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]6042<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6043<p>The '<tt>phi</tt>' instruction is used to implement the &#966; node in the
6044 SSA graph representing the function.</p>
6045
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]6046<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6047<p>The type of the incoming values is specified with the first type field. After
6048 this, the '<tt>phi</tt>' instruction takes a list of pairs as arguments, with
6049 one pair for each predecessor basic block of the current block. Only values
6050 of <a href="#t_firstclass">first class</a> type may be used as the value
6051 arguments to the PHI node. Only labels may be used as the label
6052 arguments.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]6053
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6054<p>There must be no non-phi instructions between the start of a basic block and
6055 the PHI instructions: i.e. PHI instructions must be first in a basic
6056 block.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]6057
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6058<p>For the purposes of the SSA form, the use of each incoming value is deemed to
6059 occur on the edge from the corresponding predecessor block to the current
6060 block (but after any definition of an '<tt>invoke</tt>' instruction's return
6061 value on the same edge).</p>
Jay Foadd2449092009-06-03 10:20:10 +0000[diff] [blame]6062
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]6063<h5>Semantics:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]6064<p>At runtime, the '<tt>phi</tt>' instruction logically takes on the value
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6065 specified by the pair corresponding to the predecessor basic block that
6066 executed just prior to the current block.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]6067
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]6068<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]6069<pre>
6070Loop: ; Infinite loop that counts from 0 on up...
6071 %indvar = phi i32 [ 0, %LoopHeader ], [ %nextindvar, %Loop ]
6072 %nextindvar = add i32 %indvar, 1
6073 br label %Loop
6074</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6075
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]6076</div>
6077
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]6078<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6079<h4>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]6080 <a name="i_select">'<tt>select</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6081</h4>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]6082
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6083<div>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]6084
6085<h5>Syntax:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]6086<pre>
Dan Gohmanf72fb672008-09-09 01:02:47 +0000[diff] [blame]6087 &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>
6088
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]6089 <i>selty</i> is either i1 or {&lt;N x i1&gt;}
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]6090</pre>
6091
6092<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6093<p>The '<tt>select</tt>' instruction is used to choose one value based on a
6094 condition, without branching.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]6095
6096
6097<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6098<p>The '<tt>select</tt>' instruction requires an 'i1' value or a vector of 'i1'
6099 values indicating the condition, and two values of the
6100 same <a href="#t_firstclass">first class</a> type. If the val1/val2 are
6101 vectors and the condition is a scalar, then entire vectors are selected, not
6102 individual elements.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]6103
6104<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6105<p>If the condition is an i1 and it evaluates to 1, the instruction returns the
6106 first value argument; otherwise, it returns the second value argument.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]6107
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6108<p>If the condition is a vector of i1, then the value arguments must be vectors
6109 of the same size, and the selection is done element by element.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]6110
6111<h5>Example:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]6112<pre>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]6113 %X = select i1 true, i8 17, i8 42 <i>; yields i8:17</i>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]6114</pre>
Dan Gohmanc766f722009-01-22 01:39:38 +0000[diff] [blame]6115
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]6116</div>
6117
Robert Bocchino05ccd702006-01-15 20:48:27 +0000[diff] [blame]6118<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6119<h4>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]6120 <a name="i_call">'<tt>call</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6121</h4>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]6122
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6123<div>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]6124
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]6125<h5>Syntax:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]6126<pre>
Devang Patel307e8ab2008-10-07 17:48:33 +0000[diff] [blame]6127 &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]6128</pre>
6129
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]6130<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]6131<p>The '<tt>call</tt>' instruction represents a simple function call.</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]6132
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]6133<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]6134<p>This instruction requires several arguments:</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]6135
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]6136<ol>
Jeffrey Yasskin95fa80a2010-01-09 19:44:16 +0000[diff] [blame]6137 <li>The optional "tail" marker indicates that the callee function does not
6138 access any allocas or varargs in the caller. Note that calls may be
6139 marked "tail" even if they do not occur before
6140 a <a href="#i_ret"><tt>ret</tt></a> instruction. If the "tail" marker is
6141 present, the function call is eligible for tail call optimization,
6142 but <a href="CodeGenerator.html#tailcallopt">might not in fact be
Evan Chengdc444e92010-03-08 21:05:02 +0000[diff] [blame]6143 optimized into a jump</a>. The code generator may optimize calls marked
6144 "tail" with either 1) automatic <a href="CodeGenerator.html#sibcallopt">
6145 sibling call optimization</a> when the caller and callee have
6146 matching signatures, or 2) forced tail call optimization when the
6147 following extra requirements are met:
Jeffrey Yasskin95fa80a2010-01-09 19:44:16 +0000[diff] [blame]6148 <ul>
6149 <li>Caller and callee both have the calling
6150 convention <tt>fastcc</tt>.</li>
6151 <li>The call is in tail position (ret immediately follows call and ret
6152 uses value of call or is void).</li>
6153 <li>Option <tt>-tailcallopt</tt> is enabled,
Dan Gohmanfbbee8d2010-03-02 01:08:11 +0000[diff] [blame]6154 or <code>llvm::GuaranteedTailCallOpt</code> is <code>true</code>.</li>
Jeffrey Yasskin95fa80a2010-01-09 19:44:16 +0000[diff] [blame]6155 <li><a href="CodeGenerator.html#tailcallopt">Platform specific
6156 constraints are met.</a></li>
6157 </ul>
6158 </li>
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]6159
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6160 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
6161 convention</a> the call should use. If none is specified, the call
Jeffrey Yasskin95fa80a2010-01-09 19:44:16 +0000[diff] [blame]6162 defaults to using C calling conventions. The calling convention of the
6163 call must match the calling convention of the target function, or else the
6164 behavior is undefined.</li>
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]6165
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6166 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
6167 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
6168 '<tt>inreg</tt>' attributes are valid here.</li>
6169
6170 <li>'<tt>ty</tt>': the type of the call instruction itself which is also the
6171 type of the return value. Functions that return no value are marked
6172 <tt><a href="#t_void">void</a></tt>.</li>
6173
6174 <li>'<tt>fnty</tt>': shall be the signature of the pointer to function value
6175 being invoked. The argument types must match the types implied by this
6176 signature. This type can be omitted if the function is not varargs and if
6177 the function type does not return a pointer to a function.</li>
6178
6179 <li>'<tt>fnptrval</tt>': An LLVM value containing a pointer to a function to
6180 be invoked. In most cases, this is a direct function invocation, but
6181 indirect <tt>call</tt>s are just as possible, calling an arbitrary pointer
6182 to function value.</li>
6183
6184 <li>'<tt>function args</tt>': argument list whose types match the function
Chris Lattner0724fbd2010-03-02 06:36:51 +0000[diff] [blame]6185 signature argument types and parameter attributes. All arguments must be
6186 of <a href="#t_firstclass">first class</a> type. If the function
6187 signature indicates the function accepts a variable number of arguments,
6188 the extra arguments can be specified.</li>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6189
6190 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
6191 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
6192 '<tt>readnone</tt>' attributes are valid here.</li>
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]6193</ol>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]6194
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]6195<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6196<p>The '<tt>call</tt>' instruction is used to cause control flow to transfer to
6197 a specified function, with its incoming arguments bound to the specified
6198 values. Upon a '<tt><a href="#i_ret">ret</a></tt>' instruction in the called
6199 function, control flow continues with the instruction after the function
6200 call, and the return value of the function is bound to the result
6201 argument.</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]6202
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]6203<h5>Example:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]6204<pre>
Nick Lewyckydb7e3c92007-09-08 13:57:50 +0000[diff] [blame]6205 %retval = call i32 @test(i32 %argc)
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]6206 call i32 (i8*, ...)* @printf(i8* %msg, i32 12, i8 42) <i>; yields i32</i>
Chris Lattner772fccf2008-03-21 17:24:17 +0000[diff] [blame]6207 %X = tail call i32 @foo() <i>; yields i32</i>
6208 %Y = tail call <a href="#callingconv">fastcc</a> i32 @foo() <i>; yields i32</i>
6209 call void %foo(i8 97 signext)
Devang Patelc3fc6df2008-03-10 20:49:15 +0000[diff] [blame]6210
6211 %struct.A = type { i32, i8 }
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]6212 %r = call %struct.A @foo() <i>; yields { 32, i8 }</i>
Dan Gohmanb1e6b962008-10-04 19:00:07 +0000[diff] [blame]6213 %gr = extractvalue %struct.A %r, 0 <i>; yields i32</i>
6214 %gr1 = extractvalue %struct.A %r, 1 <i>; yields i8</i>
Chris Lattner85a350f2008-10-08 06:26:11 +0000[diff] [blame]6215 %Z = call void @foo() noreturn <i>; indicates that %foo never returns normally</i>
Matthijs Kooijmancb73d192008-10-07 10:03:45 +0000[diff] [blame]6216 %ZZ = call zeroext i32 @bar() <i>; Return value is %zero extended</i>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]6217</pre>
6218
Dale Johannesen07de8d12009-09-24 18:38:21 +0000[diff] [blame]6219<p>llvm treats calls to some functions with names and arguments that match the
Dale Johannesen9f8380b2009-09-25 17:04:42 +0000[diff] [blame]6220standard C99 library as being the C99 library functions, and may perform
6221optimizations or generate code for them under that assumption. This is
6222something we'd like to change in the future to provide better support for
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]6223freestanding environments and non-C-based languages.</p>
Dale Johannesen07de8d12009-09-24 18:38:21 +0000[diff] [blame]6224
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]6225</div>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]6226
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6227<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6228<h4>
Chris Lattnerfb6977d2006-01-13 23:26:01 +0000[diff] [blame]6229 <a name="i_va_arg">'<tt>va_arg</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6230</h4>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]6231
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6232<div>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]6233
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]6234<h5>Syntax:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]6235<pre>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]6236 &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]6237</pre>
6238
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]6239<h5>Overview:</h5>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]6240<p>The '<tt>va_arg</tt>' instruction is used to access arguments passed through
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6241 the "variable argument" area of a function call. It is used to implement the
6242 <tt>va_arg</tt> macro in C.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]6243
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]6244<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6245<p>This instruction takes a <tt>va_list*</tt> value and the type of the
6246 argument. It returns a value of the specified argument type and increments
6247 the <tt>va_list</tt> to point to the next argument. The actual type
6248 of <tt>va_list</tt> is target specific.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]6249
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]6250<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6251<p>The '<tt>va_arg</tt>' instruction loads an argument of the specified type
6252 from the specified <tt>va_list</tt> and causes the <tt>va_list</tt> to point
6253 to the next argument. For more information, see the variable argument
6254 handling <a href="#int_varargs">Intrinsic Functions</a>.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]6255
6256<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]6257 take a variable number of arguments, for example, the <tt>vfprintf</tt>
6258 function.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]6259
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6260<p><tt>va_arg</tt> is an LLVM instruction instead of
6261 an <a href="#intrinsics">intrinsic function</a> because it takes a type as an
6262 argument.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]6263
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]6264<h5>Example:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]6265<p>See the <a href="#int_varargs">variable argument processing</a> section.</p>
6266
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6267<p>Note that the code generator does not yet fully support va_arg on many
6268 targets. Also, it does not currently support va_arg with aggregate types on
6269 any target.</p>
Dan Gohmanf3e60bd2009-01-12 23:12:39 +0000[diff] [blame]6270
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]6271</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6272
Bill Wendlingf78faf82011-08-02 21:52:38 +0000[diff] [blame]6273<!-- _______________________________________________________________________ -->
6274<h4>
6275 <a name="i_landingpad">'<tt>landingpad</tt>' Instruction</a>
6276</h4>
6277
6278<div>
6279
6280<h5>Syntax:</h5>
6281<pre>
Duncan Sands8d6796b2012-01-13 19:59:16 +0000[diff] [blame]6282 &lt;resultval&gt; = landingpad &lt;resultty&gt; personality &lt;type&gt; &lt;pers_fn&gt; &lt;clause&gt;+
6283 &lt;resultval&gt; = landingpad &lt;resultty&gt; personality &lt;type&gt; &lt;pers_fn&gt; cleanup &lt;clause&gt;*
Bill Wendlingbf13ee12011-08-08 08:06:05 +0000[diff] [blame]6284
Bill Wendlingf78faf82011-08-02 21:52:38 +0000[diff] [blame]6285 &lt;clause&gt; := catch &lt;type&gt; &lt;value&gt;
Bill Wendlinge6e88262011-08-12 20:24:12 +0000[diff] [blame]6286 &lt;clause&gt; := filter &lt;array constant type&gt; &lt;array constant&gt;
Bill Wendlingf78faf82011-08-02 21:52:38 +0000[diff] [blame]6287</pre>
6288
6289<h5>Overview:</h5>
6290<p>The '<tt>landingpad</tt>' instruction is used by
6291 <a href="ExceptionHandling.html#overview">LLVM's exception handling
6292 system</a> to specify that a basic block is a landing pad &mdash; one where
6293 the exception lands, and corresponds to the code found in the
6294 <i><tt>catch</tt></i> portion of a <i><tt>try/catch</tt></i> sequence. It
6295 defines values supplied by the personality function (<tt>pers_fn</tt>) upon
6296 re-entry to the function. The <tt>resultval</tt> has the
Duncan Sands8d6796b2012-01-13 19:59:16 +0000[diff] [blame]6297 type <tt>resultty</tt>.</p>
Bill Wendlingf78faf82011-08-02 21:52:38 +0000[diff] [blame]6298
6299<h5>Arguments:</h5>
6300<p>This instruction takes a <tt>pers_fn</tt> value. This is the personality
6301 function associated with the unwinding mechanism. The optional
6302 <tt>cleanup</tt> flag indicates that the landing pad block is a cleanup.</p>
6303
6304<p>A <tt>clause</tt> begins with the clause type &mdash; <tt>catch</tt>
Bill Wendlinge6e88262011-08-12 20:24:12 +0000[diff] [blame]6305 or <tt>filter</tt> &mdash; and contains the global variable representing the
6306 "type" that may be caught or filtered respectively. Unlike the
6307 <tt>catch</tt> clause, the <tt>filter</tt> clause takes an array constant as
6308 its argument. Use "<tt>[0 x i8**] undef</tt>" for a filter which cannot
6309 throw. The '<tt>landingpad</tt>' instruction must contain <em>at least</em>
Bill Wendlingf78faf82011-08-02 21:52:38 +0000[diff] [blame]6310 one <tt>clause</tt> or the <tt>cleanup</tt> flag.</p>
6311
6312<h5>Semantics:</h5>
6313<p>The '<tt>landingpad</tt>' instruction defines the values which are set by the
6314 personality function (<tt>pers_fn</tt>) upon re-entry to the function, and
6315 therefore the "result type" of the <tt>landingpad</tt> instruction. As with
6316 calling conventions, how the personality function results are represented in
6317 LLVM IR is target specific.</p>
6318
Bill Wendlingb7a01352011-08-03 17:17:06 +0000[diff] [blame]6319<p>The clauses are applied in order from top to bottom. If two
6320 <tt>landingpad</tt> instructions are merged together through inlining, the
Duncan Sands8d6796b2012-01-13 19:59:16 +0000[diff] [blame]6321 clauses from the calling function are appended to the list of clauses.
6322 When the call stack is being unwound due to an exception being thrown, the
6323 exception is compared against each <tt>clause</tt> in turn. If it doesn't
6324 match any of the clauses, and the <tt>cleanup</tt> flag is not set, then
6325 unwinding continues further up the call stack.</p>
Bill Wendlingb7a01352011-08-03 17:17:06 +0000[diff] [blame]6326
Bill Wendlingf78faf82011-08-02 21:52:38 +0000[diff] [blame]6327<p>The <tt>landingpad</tt> instruction has several restrictions:</p>
6328
6329<ul>
6330 <li>A landing pad block is a basic block which is the unwind destination of an
6331 '<tt>invoke</tt>' instruction.</li>
6332 <li>A landing pad block must have a '<tt>landingpad</tt>' instruction as its
6333 first non-PHI instruction.</li>
6334 <li>There can be only one '<tt>landingpad</tt>' instruction within the landing
6335 pad block.</li>
6336 <li>A basic block that is not a landing pad block may not include a
6337 '<tt>landingpad</tt>' instruction.</li>
6338 <li>All '<tt>landingpad</tt>' instructions in a function must have the same
6339 personality function.</li>
6340</ul>
6341
6342<h5>Example:</h5>
6343<pre>
6344 ;; A landing pad which can catch an integer.
6345 %res = landingpad { i8*, i32 } personality i32 (...)* @__gxx_personality_v0
6346 catch i8** @_ZTIi
6347 ;; A landing pad that is a cleanup.
6348 %res = landingpad { i8*, i32 } personality i32 (...)* @__gxx_personality_v0
Bill Wendlinge6e88262011-08-12 20:24:12 +0000[diff] [blame]6349 cleanup
Bill Wendlingf78faf82011-08-02 21:52:38 +0000[diff] [blame]6350 ;; A landing pad which can catch an integer and can only throw a double.
6351 %res = landingpad { i8*, i32 } personality i32 (...)* @__gxx_personality_v0
6352 catch i8** @_ZTIi
Bill Wendlinge6e88262011-08-12 20:24:12 +0000[diff] [blame]6353 filter [1 x i8**] [@_ZTId]
Bill Wendlingf78faf82011-08-02 21:52:38 +0000[diff] [blame]6354</pre>
6355
6356</div>
6357
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6358</div>
6359
6360</div>
6361
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6362<!-- *********************************************************************** -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6363<h2><a name="intrinsics">Intrinsic Functions</a></h2>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]6364<!-- *********************************************************************** -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6365
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6366<div>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6367
6368<p>LLVM supports the notion of an "intrinsic function". These functions have
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6369 well known names and semantics and are required to follow certain
6370 restrictions. Overall, these intrinsics represent an extension mechanism for
6371 the LLVM language that does not require changing all of the transformations
6372 in LLVM when adding to the language (or the bitcode reader/writer, the
6373 parser, etc...).</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6374
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]6375<p>Intrinsic function names must all start with an "<tt>llvm.</tt>" prefix. This
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6376 prefix is reserved in LLVM for intrinsic names; thus, function names may not
6377 begin with this prefix. Intrinsic functions must always be external
6378 functions: you cannot define the body of intrinsic functions. Intrinsic
6379 functions may only be used in call or invoke instructions: it is illegal to
6380 take the address of an intrinsic function. Additionally, because intrinsic
6381 functions are part of the LLVM language, it is required if any are added that
6382 they be documented here.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6383
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6384<p>Some intrinsic functions can be overloaded, i.e., the intrinsic represents a
6385 family of functions that perform the same operation but on different data
6386 types. Because LLVM can represent over 8 million different integer types,
6387 overloading is used commonly to allow an intrinsic function to operate on any
6388 integer type. One or more of the argument types or the result type can be
6389 overloaded to accept any integer type. Argument types may also be defined as
6390 exactly matching a previous argument's type or the result type. This allows
6391 an intrinsic function which accepts multiple arguments, but needs all of them
6392 to be of the same type, to only be overloaded with respect to a single
6393 argument or the result.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6394
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6395<p>Overloaded intrinsics will have the names of its overloaded argument types
6396 encoded into its function name, each preceded by a period. Only those types
6397 which are overloaded result in a name suffix. Arguments whose type is matched
6398 against another type do not. For example, the <tt>llvm.ctpop</tt> function
6399 can take an integer of any width and returns an integer of exactly the same
6400 integer width. This leads to a family of functions such as
6401 <tt>i8 @llvm.ctpop.i8(i8 %val)</tt> and <tt>i29 @llvm.ctpop.i29(i29
6402 %val)</tt>. Only one type, the return type, is overloaded, and only one type
6403 suffix is required. Because the argument's type is matched against the return
6404 type, it does not require its own name suffix.</p>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]6405
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]6406<p>To learn how to add an intrinsic function, please see the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6407 <a href="ExtendingLLVM.html">Extending LLVM Guide</a>.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6408
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6409<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6410<h3>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6411 <a name="int_varargs">Variable Argument Handling Intrinsics</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6412</h3>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6413
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6414<div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6415
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6416<p>Variable argument support is defined in LLVM with
6417 the <a href="#i_va_arg"><tt>va_arg</tt></a> instruction and these three
6418 intrinsic functions. These functions are related to the similarly named
6419 macros defined in the <tt>&lt;stdarg.h&gt;</tt> header file.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6420
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6421<p>All of these functions operate on arguments that use a target-specific value
6422 type "<tt>va_list</tt>". The LLVM assembly language reference manual does
6423 not define what this type is, so all transformations should be prepared to
6424 handle these functions regardless of the type used.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6425
Chris Lattner374ab302006-05-15 17:26:46 +0000[diff] [blame]6426<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]6427 instruction and the variable argument handling intrinsic functions are
6428 used.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6429
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]6430<pre class="doc_code">
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]6431define i32 @test(i32 %X, ...) {
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6432 ; Initialize variable argument processing
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]6433 %ap = alloca i8*
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]6434 %ap2 = bitcast i8** %ap to i8*
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]6435 call void @llvm.va_start(i8* %ap2)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6436
6437 ; Read a single integer argument
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]6438 %tmp = va_arg i8** %ap, i32
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6439
6440 ; Demonstrate usage of llvm.va_copy and llvm.va_end
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]6441 %aq = alloca i8*
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]6442 %aq2 = bitcast i8** %aq to i8*
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]6443 call void @llvm.va_copy(i8* %aq2, i8* %ap2)
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]6444 call void @llvm.va_end(i8* %aq2)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6445
6446 ; Stop processing of arguments.
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]6447 call void @llvm.va_end(i8* %ap2)
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]6448 ret i32 %tmp
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6449}
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]6450
6451declare void @llvm.va_start(i8*)
6452declare void @llvm.va_copy(i8*, i8*)
6453declare void @llvm.va_end(i8*)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6454</pre>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6455
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6456<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6457<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6458 <a name="int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6459</h4>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6460
6461
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6462<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6463
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6464<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6465<pre>
6466 declare void %llvm.va_start(i8* &lt;arglist&gt;)
6467</pre>
6468
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6469<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6470<p>The '<tt>llvm.va_start</tt>' intrinsic initializes <tt>*&lt;arglist&gt;</tt>
6471 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]6472
6473<h5>Arguments:</h5>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]6474<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]6475
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6476<h5>Semantics:</h5>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]6477<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]6478 macro available in C. In a target-dependent way, it initializes
6479 the <tt>va_list</tt> element to which the argument points, so that the next
6480 call to <tt>va_arg</tt> will produce the first variable argument passed to
6481 the function. Unlike the C <tt>va_start</tt> macro, this intrinsic does not
6482 need to know the last argument of the function as the compiler can figure
6483 that out.</p>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]6484
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]6485</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6486
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6487<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6488<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6489 <a name="int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6490</h4>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6491
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6492<div>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]6493
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6494<h5>Syntax:</h5>
6495<pre>
6496 declare void @llvm.va_end(i8* &lt;arglist&gt;)
6497</pre>
6498
6499<h5>Overview:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]6500<p>The '<tt>llvm.va_end</tt>' intrinsic destroys <tt>*&lt;arglist&gt;</tt>,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6501 which has been initialized previously
6502 with <tt><a href="#int_va_start">llvm.va_start</a></tt>
6503 or <tt><a href="#i_va_copy">llvm.va_copy</a></tt>.</p>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]6504
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6505<h5>Arguments:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]6506<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]6507
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6508<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]6509<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]6510 macro available in C. In a target-dependent way, it destroys
6511 the <tt>va_list</tt> element to which the argument points. Calls
6512 to <a href="#int_va_start"><tt>llvm.va_start</tt></a>
6513 and <a href="#int_va_copy"> <tt>llvm.va_copy</tt></a> must be matched exactly
6514 with calls to <tt>llvm.va_end</tt>.</p>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]6515
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]6516</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6517
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6518<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6519<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6520 <a name="int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6521</h4>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6522
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6523<div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6524
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6525<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6526<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]6527 declare void @llvm.va_copy(i8* &lt;destarglist&gt;, i8* &lt;srcarglist&gt;)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6528</pre>
6529
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6530<h5>Overview:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]6531<p>The '<tt>llvm.va_copy</tt>' intrinsic copies the current argument position
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6532 from the source argument list to the destination argument list.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6533
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6534<h5>Arguments:</h5>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]6535<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]6536 The second argument is a pointer to a <tt>va_list</tt> element to copy
6537 from.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6538
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6539<h5>Semantics:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]6540<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]6541 macro available in C. In a target-dependent way, it copies the
6542 source <tt>va_list</tt> element into the destination <tt>va_list</tt>
6543 element. This intrinsic is necessary because
6544 the <tt><a href="#int_va_start"> llvm.va_start</a></tt> intrinsic may be
6545 arbitrarily complex and require, for example, memory allocation.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6546
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]6547</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6548
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6549</div>
6550
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6551<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6552<h3>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6553 <a name="int_gc">Accurate Garbage Collection Intrinsics</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6554</h3>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6555
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6556<div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6557
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6558<p>LLVM support for <a href="GarbageCollection.html">Accurate Garbage
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]6559Collection</a> (GC) requires the implementation and generation of these
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6560intrinsics. These intrinsics allow identification of <a href="#int_gcroot">GC
6561roots on the stack</a>, as well as garbage collector implementations that
6562require <a href="#int_gcread">read</a> and <a href="#int_gcwrite">write</a>
6563barriers. Front-ends for type-safe garbage collected languages should generate
6564these intrinsics to make use of the LLVM garbage collectors. For more details,
6565see <a href="GarbageCollection.html">Accurate Garbage Collection with
6566LLVM</a>.</p>
Christopher Lamb303dae92007-12-17 01:00:21 +0000[diff] [blame]6567
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6568<p>The garbage collection intrinsics only operate on objects in the generic
6569 address space (address space zero).</p>
Christopher Lamb303dae92007-12-17 01:00:21 +0000[diff] [blame]6570
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6571<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6572<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6573 <a name="int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6574</h4>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6575
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6576<div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6577
6578<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6579<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]6580 declare void @llvm.gcroot(i8** %ptrloc, i8* %metadata)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6581</pre>
6582
6583<h5>Overview:</h5>
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]6584<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]6585 the code generator, and allows some metadata to be associated with it.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6586
6587<h5>Arguments:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6588<p>The first argument specifies the address of a stack object that contains the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6589 root pointer. The second pointer (which must be either a constant or a
6590 global value address) contains the meta-data to be associated with the
6591 root.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6592
6593<h5>Semantics:</h5>
Chris Lattner05d67092008-04-24 05:59:56 +0000[diff] [blame]6594<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]6595 location. At compile-time, the code generator generates information to allow
6596 the runtime to find the pointer at GC safe points. The '<tt>llvm.gcroot</tt>'
6597 intrinsic may only be used in a function which <a href="#gc">specifies a GC
6598 algorithm</a>.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6599
6600</div>
6601
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6602<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6603<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6604 <a name="int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6605</h4>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6606
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6607<div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6608
6609<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6610<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]6611 declare i8* @llvm.gcread(i8* %ObjPtr, i8** %Ptr)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6612</pre>
6613
6614<h5>Overview:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6615<p>The '<tt>llvm.gcread</tt>' intrinsic identifies reads of references from heap
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6616 locations, allowing garbage collector implementations that require read
6617 barriers.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6618
6619<h5>Arguments:</h5>
Chris Lattner80626e92006-03-14 20:02:51 +0000[diff] [blame]6620<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]6621 allocated from the garbage collector. The first object is a pointer to the
6622 start of the referenced object, if needed by the language runtime (otherwise
6623 null).</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6624
6625<h5>Semantics:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6626<p>The '<tt>llvm.gcread</tt>' intrinsic has the same semantics as a load
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6627 instruction, but may be replaced with substantially more complex code by the
6628 garbage collector runtime, as needed. The '<tt>llvm.gcread</tt>' intrinsic
6629 may only be used in a function which <a href="#gc">specifies a GC
6630 algorithm</a>.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6631
6632</div>
6633
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6634<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6635<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6636 <a name="int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6637</h4>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6638
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6639<div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6640
6641<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6642<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]6643 declare void @llvm.gcwrite(i8* %P1, i8* %Obj, i8** %P2)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6644</pre>
6645
6646<h5>Overview:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6647<p>The '<tt>llvm.gcwrite</tt>' intrinsic identifies writes of references to heap
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6648 locations, allowing garbage collector implementations that require write
6649 barriers (such as generational or reference counting collectors).</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6650
6651<h5>Arguments:</h5>
Chris Lattner80626e92006-03-14 20:02:51 +0000[diff] [blame]6652<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]6653 object to store it to, and the third is the address of the field of Obj to
6654 store to. If the runtime does not require a pointer to the object, Obj may
6655 be null.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6656
6657<h5>Semantics:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6658<p>The '<tt>llvm.gcwrite</tt>' intrinsic has the same semantics as a store
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6659 instruction, but may be replaced with substantially more complex code by the
6660 garbage collector runtime, as needed. The '<tt>llvm.gcwrite</tt>' intrinsic
6661 may only be used in a function which <a href="#gc">specifies a GC
6662 algorithm</a>.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6663
6664</div>
6665
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6666</div>
6667
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6668<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6669<h3>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6670 <a name="int_codegen">Code Generator Intrinsics</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6671</h3>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6672
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6673<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6674
6675<p>These intrinsics are provided by LLVM to expose special features that may
6676 only be implemented with code generator support.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6677
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6678<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6679<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6680 <a name="int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6681</h4>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6682
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6683<div>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6684
6685<h5>Syntax:</h5>
6686<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]6687 declare i8 *@llvm.returnaddress(i32 &lt;level&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6688</pre>
6689
6690<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6691<p>The '<tt>llvm.returnaddress</tt>' intrinsic attempts to compute a
6692 target-specific value indicating the return address of the current function
6693 or one of its callers.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6694
6695<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6696<p>The argument to this intrinsic indicates which function to return the address
6697 for. Zero indicates the calling function, one indicates its caller, etc.
6698 The argument is <b>required</b> to be a constant integer value.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6699
6700<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6701<p>The '<tt>llvm.returnaddress</tt>' intrinsic either returns a pointer
6702 indicating the return address of the specified call frame, or zero if it
6703 cannot be identified. The value returned by this intrinsic is likely to be
6704 incorrect or 0 for arguments other than zero, so it should only be used for
6705 debugging purposes.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6706
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6707<p>Note that calling this intrinsic does not prevent function inlining or other
6708 aggressive transformations, so the value returned may not be that of the
6709 obvious source-language caller.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6710
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6711</div>
6712
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6713<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6714<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6715 <a name="int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6716</h4>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6717
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6718<div>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6719
6720<h5>Syntax:</h5>
6721<pre>
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]6722 declare i8* @llvm.frameaddress(i32 &lt;level&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6723</pre>
6724
6725<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6726<p>The '<tt>llvm.frameaddress</tt>' intrinsic attempts to return the
6727 target-specific frame pointer value for the specified stack frame.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6728
6729<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6730<p>The argument to this intrinsic indicates which function to return the frame
6731 pointer for. Zero indicates the calling function, one indicates its caller,
6732 etc. The argument is <b>required</b> to be a constant integer value.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6733
6734<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6735<p>The '<tt>llvm.frameaddress</tt>' intrinsic either returns a pointer
6736 indicating the frame address of the specified call frame, or zero if it
6737 cannot be identified. The value returned by this intrinsic is likely to be
6738 incorrect or 0 for arguments other than zero, so it should only be used for
6739 debugging purposes.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6740
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6741<p>Note that calling this intrinsic does not prevent function inlining or other
6742 aggressive transformations, so the value returned may not be that of the
6743 obvious source-language caller.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6744
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6745</div>
6746
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]6747<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6748<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6749 <a name="int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6750</h4>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]6751
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6752<div>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]6753
6754<h5>Syntax:</h5>
6755<pre>
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]6756 declare i8* @llvm.stacksave()
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]6757</pre>
6758
6759<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6760<p>The '<tt>llvm.stacksave</tt>' intrinsic is used to remember the current state
6761 of the function stack, for use
6762 with <a href="#int_stackrestore"> <tt>llvm.stackrestore</tt></a>. This is
6763 useful for implementing language features like scoped automatic variable
6764 sized arrays in C99.</p>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]6765
6766<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6767<p>This intrinsic returns a opaque pointer value that can be passed
6768 to <a href="#int_stackrestore"><tt>llvm.stackrestore</tt></a>. When
6769 an <tt>llvm.stackrestore</tt> intrinsic is executed with a value saved
6770 from <tt>llvm.stacksave</tt>, it effectively restores the state of the stack
6771 to the state it was in when the <tt>llvm.stacksave</tt> intrinsic executed.
6772 In practice, this pops any <a href="#i_alloca">alloca</a> blocks from the
6773 stack that were allocated after the <tt>llvm.stacksave</tt> was executed.</p>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]6774
6775</div>
6776
6777<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6778<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6779 <a name="int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6780</h4>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]6781
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6782<div>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]6783
6784<h5>Syntax:</h5>
6785<pre>
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]6786 declare void @llvm.stackrestore(i8* %ptr)
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]6787</pre>
6788
6789<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6790<p>The '<tt>llvm.stackrestore</tt>' intrinsic is used to restore the state of
6791 the function stack to the state it was in when the
6792 corresponding <a href="#int_stacksave"><tt>llvm.stacksave</tt></a> intrinsic
6793 executed. This is useful for implementing language features like scoped
6794 automatic variable sized arrays in C99.</p>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]6795
6796<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6797<p>See the description
6798 for <a href="#int_stacksave"><tt>llvm.stacksave</tt></a>.</p>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]6799
6800</div>
6801
Chris Lattner57e1f392006-01-13 02:03:13 +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_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6805</h4>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]6806
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6807<div>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]6808
6809<h5>Syntax:</h5>
6810<pre>
Bruno Cardoso Lopes9a767332011-06-14 04:58:37 +0000[diff] [blame]6811 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]6812</pre>
6813
6814<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6815<p>The '<tt>llvm.prefetch</tt>' intrinsic is a hint to the code generator to
6816 insert a prefetch instruction if supported; otherwise, it is a noop.
6817 Prefetches have no effect on the behavior of the program but can change its
6818 performance characteristics.</p>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]6819
6820<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6821<p><tt>address</tt> is the address to be prefetched, <tt>rw</tt> is the
6822 specifier determining if the fetch should be for a read (0) or write (1),
6823 and <tt>locality</tt> is a temporal locality specifier ranging from (0) - no
Bruno Cardoso Lopes9a767332011-06-14 04:58:37 +0000[diff] [blame]6824 locality, to (3) - extremely local keep in cache. The <tt>cache type</tt>
6825 specifies whether the prefetch is performed on the data (1) or instruction (0)
6826 cache. The <tt>rw</tt>, <tt>locality</tt> and <tt>cache type</tt> arguments
6827 must be constant integers.</p>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]6828
6829<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6830<p>This intrinsic does not modify the behavior of the program. In particular,
6831 prefetches cannot trap and do not produce a value. On targets that support
6832 this intrinsic, the prefetch can provide hints to the processor cache for
6833 better performance.</p>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]6834
6835</div>
6836
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]6837<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6838<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6839 <a name="int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6840</h4>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]6841
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6842<div>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]6843
6844<h5>Syntax:</h5>
6845<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]6846 declare void @llvm.pcmarker(i32 &lt;id&gt;)
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]6847</pre>
6848
6849<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6850<p>The '<tt>llvm.pcmarker</tt>' intrinsic is a method to export a Program
6851 Counter (PC) in a region of code to simulators and other tools. The method
6852 is target specific, but it is expected that the marker will use exported
6853 symbols to transmit the PC of the marker. The marker makes no guarantees
6854 that it will remain with any specific instruction after optimizations. It is
6855 possible that the presence of a marker will inhibit optimizations. The
6856 intended use is to be inserted after optimizations to allow correlations of
6857 simulation runs.</p>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]6858
6859<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6860<p><tt>id</tt> is a numerical id identifying the marker.</p>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]6861
6862<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6863<p>This intrinsic does not modify the behavior of the program. Backends that do
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]6864 not support this intrinsic may ignore it.</p>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]6865
6866</div>
6867
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]6868<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6869<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6870 <a name="int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6871</h4>
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]6872
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6873<div>
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]6874
6875<h5>Syntax:</h5>
6876<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]6877 declare i64 @llvm.readcyclecounter()
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]6878</pre>
6879
6880<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6881<p>The '<tt>llvm.readcyclecounter</tt>' intrinsic provides access to the cycle
6882 counter register (or similar low latency, high accuracy clocks) on those
6883 targets that support it. On X86, it should map to RDTSC. On Alpha, it
6884 should map to RPCC. As the backing counters overflow quickly (on the order
6885 of 9 seconds on alpha), this should only be used for small timings.</p>
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]6886
6887<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6888<p>When directly supported, reading the cycle counter should not modify any
6889 memory. Implementations are allowed to either return a application specific
6890 value or a system wide value. On backends without support, this is lowered
6891 to a constant 0.</p>
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]6892
6893</div>
6894
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6895</div>
6896
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6897<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6898<h3>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6899 <a name="int_libc">Standard C Library Intrinsics</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6900</h3>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6901
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6902<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6903
6904<p>LLVM provides intrinsics for a few important standard C library functions.
6905 These intrinsics allow source-language front-ends to pass information about
6906 the alignment of the pointer arguments to the code generator, providing
6907 opportunity for more efficient code generation.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6908
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6909<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6910<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6911 <a name="int_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6912</h4>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6913
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6914<div>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6915
6916<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6917<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]6918 integer bit width and for different address spaces. Not all targets support
6919 all bit widths however.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6920
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6921<pre>
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]6922 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]6923 i32 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]6924 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]6925 i64 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Chris Lattner33aec9e2004-02-12 17:01:32 +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.memcpy.*</tt>' intrinsics copy a block of memory from the
6930 source location to the destination location.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6931
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6932<p>Note that, unlike the standard libc function, the <tt>llvm.memcpy.*</tt>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6933 intrinsics do not return a value, takes extra alignment/isvolatile arguments
6934 and the pointers can be in specified address spaces.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6935
6936<h5>Arguments:</h5>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6937
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6938<p>The first argument is a pointer to the destination, the second is a pointer
6939 to the source. The third argument is an integer argument specifying the
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6940 number of bytes to copy, the fourth argument is the alignment of the
6941 source and destination locations, and the fifth is a boolean indicating a
6942 volatile access.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6943
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]6944<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]6945 then the caller guarantees that both the source and destination pointers are
6946 aligned to that boundary.</p>
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]6947
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]6948<p>If the <tt>isvolatile</tt> parameter is <tt>true</tt>, the
6949 <tt>llvm.memcpy</tt> call is a <a href="#volatile">volatile operation</a>.
6950 The detailed access behavior is not very cleanly specified and it is unwise
6951 to depend on it.</p>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6952
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6953<h5>Semantics:</h5>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6954
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6955<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
6956 source location to the destination location, which are not allowed to
6957 overlap. It copies "len" bytes of memory over. If the argument is known to
6958 be aligned to some boundary, this can be specified as the fourth argument,
6959 otherwise it should be set to 0 or 1.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6960
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6961</div>
6962
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6963<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6964<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6965 <a name="int_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6966</h4>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6967
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6968<div>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6969
6970<h5>Syntax:</h5>
Chris Lattner824b9582008-11-21 16:42:48 +0000[diff] [blame]6971<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]6972 width and for different address space. Not all targets support all bit
6973 widths however.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6974
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6975<pre>
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]6976 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]6977 i32 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]6978 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]6979 i64 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6980</pre>
6981
6982<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6983<p>The '<tt>llvm.memmove.*</tt>' intrinsics move a block of memory from the
6984 source location to the destination location. It is similar to the
6985 '<tt>llvm.memcpy</tt>' intrinsic but allows the two memory locations to
6986 overlap.</p>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6987
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6988<p>Note that, unlike the standard libc function, the <tt>llvm.memmove.*</tt>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6989 intrinsics do not return a value, takes extra alignment/isvolatile arguments
6990 and the pointers can be in specified address spaces.</p>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6991
6992<h5>Arguments:</h5>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6993
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6994<p>The first argument is a pointer to the destination, the second is a pointer
6995 to the source. The third argument is an integer argument specifying the
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6996 number of bytes to copy, the fourth argument is the alignment of the
6997 source and destination locations, and the fifth is a boolean indicating a
6998 volatile access.</p>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6999
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]7000<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]7001 then the caller guarantees that the source and destination pointers are
7002 aligned to that boundary.</p>
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]7003
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]7004<p>If the <tt>isvolatile</tt> parameter is <tt>true</tt>, the
7005 <tt>llvm.memmove</tt> call is a <a href="#volatile">volatile operation</a>.
7006 The detailed access behavior is not very cleanly specified and it is unwise
7007 to depend on it.</p>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]7008
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]7009<h5>Semantics:</h5>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]7010
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7011<p>The '<tt>llvm.memmove.*</tt>' intrinsics copy a block of memory from the
7012 source location to the destination location, which may overlap. It copies
7013 "len" bytes of memory over. If the argument is known to be aligned to some
7014 boundary, this can be specified as the fourth argument, otherwise it should
7015 be set to 0 or 1.</p>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]7016
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]7017</div>
7018
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]7019<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7020<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]7021 <a name="int_memset">'<tt>llvm.memset.*</tt>' Intrinsics</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7022</h4>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]7023
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7024<div>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]7025
7026<h5>Syntax:</h5>
Chris Lattner824b9582008-11-21 16:42:48 +0000[diff] [blame]7027<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]7028 width and for different address spaces. However, not all targets support all
7029 bit widths.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7030
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]7031<pre>
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]7032 declare void @llvm.memset.p0i8.i32(i8* &lt;dest&gt;, i8 &lt;val&gt;,
Chris Lattnerff35c3f2010-04-08 00:54:34 +0000[diff] [blame]7033 i32 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]7034 declare void @llvm.memset.p0i8.i64(i8* &lt;dest&gt;, i8 &lt;val&gt;,
Chris Lattnerff35c3f2010-04-08 00:54:34 +0000[diff] [blame]7035 i64 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]7036</pre>
7037
7038<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7039<p>The '<tt>llvm.memset.*</tt>' intrinsics fill a block of memory with a
7040 particular byte value.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]7041
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7042<p>Note that, unlike the standard libc function, the <tt>llvm.memset</tt>
John Criswellcdcbbfc2010-07-30 16:30:28 +0000[diff] [blame]7043 intrinsic does not return a value and takes extra alignment/volatile
7044 arguments. Also, the destination can be in an arbitrary address space.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]7045
7046<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7047<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]7048 byte value with which to fill it, the third argument is an integer argument
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7049 specifying the number of bytes to fill, and the fourth argument is the known
John Criswellcdcbbfc2010-07-30 16:30:28 +0000[diff] [blame]7050 alignment of the destination location.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]7051
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]7052<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]7053 then the caller guarantees that the destination pointer is aligned to that
7054 boundary.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]7055
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]7056<p>If the <tt>isvolatile</tt> parameter is <tt>true</tt>, the
7057 <tt>llvm.memset</tt> call is a <a href="#volatile">volatile operation</a>.
7058 The detailed access behavior is not very cleanly specified and it is unwise
7059 to depend on it.</p>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]7060
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]7061<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7062<p>The '<tt>llvm.memset.*</tt>' intrinsics fill "len" bytes of memory starting
7063 at the destination location. If the argument is known to be aligned to some
7064 boundary, this can be specified as the fourth argument, otherwise it should
7065 be set to 0 or 1.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]7066
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]7067</div>
7068
Chris Lattner32006282004-06-11 02:28:03 +0000[diff] [blame]7069<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7070<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]7071 <a name="int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7072</h4>
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]7073
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7074<div>
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]7075
7076<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7077<p>This is an overloaded intrinsic. You can use <tt>llvm.sqrt</tt> on any
7078 floating point or vector of floating point type. Not all targets support all
7079 types however.</p>
7080
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]7081<pre>
Dale Johannesen408f9c12007-10-02 17:47:38 +0000[diff] [blame]7082 declare float @llvm.sqrt.f32(float %Val)
7083 declare double @llvm.sqrt.f64(double %Val)
7084 declare x86_fp80 @llvm.sqrt.f80(x86_fp80 %Val)
7085 declare fp128 @llvm.sqrt.f128(fp128 %Val)
7086 declare ppc_fp128 @llvm.sqrt.ppcf128(ppc_fp128 %Val)
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]7087</pre>
7088
7089<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7090<p>The '<tt>llvm.sqrt</tt>' intrinsics return the sqrt of the specified operand,
7091 returning the same value as the libm '<tt>sqrt</tt>' functions would.
7092 Unlike <tt>sqrt</tt> in libm, however, <tt>llvm.sqrt</tt> has undefined
7093 behavior for negative numbers other than -0.0 (which allows for better
7094 optimization, because there is no need to worry about errno being
7095 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]7096
7097<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7098<p>The argument and return value are floating point numbers of the same
7099 type.</p>
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]7100
7101<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7102<p>This function returns the sqrt of the specified operand if it is a
7103 nonnegative floating point number.</p>
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]7104
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]7105</div>
7106
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]7107<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7108<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]7109 <a name="int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7110</h4>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]7111
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7112<div>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]7113
7114<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7115<p>This is an overloaded intrinsic. You can use <tt>llvm.powi</tt> on any
7116 floating point or vector of floating point type. Not all targets support all
7117 types however.</p>
7118
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]7119<pre>
Dale Johannesen408f9c12007-10-02 17:47:38 +0000[diff] [blame]7120 declare float @llvm.powi.f32(float %Val, i32 %power)
7121 declare double @llvm.powi.f64(double %Val, i32 %power)
7122 declare x86_fp80 @llvm.powi.f80(x86_fp80 %Val, i32 %power)
7123 declare fp128 @llvm.powi.f128(fp128 %Val, i32 %power)
7124 declare ppc_fp128 @llvm.powi.ppcf128(ppc_fp128 %Val, i32 %power)
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]7125</pre>
7126
7127<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7128<p>The '<tt>llvm.powi.*</tt>' intrinsics return the first operand raised to the
7129 specified (positive or negative) power. The order of evaluation of
7130 multiplications is not defined. When a vector of floating point type is
7131 used, the second argument remains a scalar integer value.</p>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]7132
7133<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7134<p>The second argument is an integer power, and the first is a value to raise to
7135 that power.</p>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]7136
7137<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7138<p>This function returns the first value raised to the second power with an
7139 unspecified sequence of rounding operations.</p>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]7140
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]7141</div>
7142
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7143<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7144<h4>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7145 <a name="int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7146</h4>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7147
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7148<div>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7149
7150<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7151<p>This is an overloaded intrinsic. You can use <tt>llvm.sin</tt> on any
7152 floating point or vector of floating point type. Not all targets support all
7153 types however.</p>
7154
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7155<pre>
7156 declare float @llvm.sin.f32(float %Val)
7157 declare double @llvm.sin.f64(double %Val)
7158 declare x86_fp80 @llvm.sin.f80(x86_fp80 %Val)
7159 declare fp128 @llvm.sin.f128(fp128 %Val)
7160 declare ppc_fp128 @llvm.sin.ppcf128(ppc_fp128 %Val)
7161</pre>
7162
7163<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7164<p>The '<tt>llvm.sin.*</tt>' intrinsics return the sine of the operand.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7165
7166<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7167<p>The argument and return value are floating point numbers of the same
7168 type.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7169
7170<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7171<p>This function returns the sine of the specified operand, returning the same
7172 values as the libm <tt>sin</tt> functions would, and handles error conditions
7173 in the same way.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7174
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7175</div>
7176
7177<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7178<h4>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7179 <a name="int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7180</h4>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7181
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7182<div>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7183
7184<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7185<p>This is an overloaded intrinsic. You can use <tt>llvm.cos</tt> on any
7186 floating point or vector of floating point type. Not all targets support all
7187 types however.</p>
7188
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7189<pre>
7190 declare float @llvm.cos.f32(float %Val)
7191 declare double @llvm.cos.f64(double %Val)
7192 declare x86_fp80 @llvm.cos.f80(x86_fp80 %Val)
7193 declare fp128 @llvm.cos.f128(fp128 %Val)
7194 declare ppc_fp128 @llvm.cos.ppcf128(ppc_fp128 %Val)
7195</pre>
7196
7197<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7198<p>The '<tt>llvm.cos.*</tt>' intrinsics return the cosine of the operand.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7199
7200<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7201<p>The argument and return value are floating point numbers of the same
7202 type.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7203
7204<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7205<p>This function returns the cosine of the specified operand, returning the same
7206 values as the libm <tt>cos</tt> functions would, and handles error conditions
7207 in the same way.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7208
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7209</div>
7210
7211<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7212<h4>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7213 <a name="int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7214</h4>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7215
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7216<div>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7217
7218<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7219<p>This is an overloaded intrinsic. You can use <tt>llvm.pow</tt> on any
7220 floating point or vector of floating point type. Not all targets support all
7221 types however.</p>
7222
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7223<pre>
7224 declare float @llvm.pow.f32(float %Val, float %Power)
7225 declare double @llvm.pow.f64(double %Val, double %Power)
7226 declare x86_fp80 @llvm.pow.f80(x86_fp80 %Val, x86_fp80 %Power)
7227 declare fp128 @llvm.pow.f128(fp128 %Val, fp128 %Power)
7228 declare ppc_fp128 @llvm.pow.ppcf128(ppc_fp128 %Val, ppc_fp128 Power)
7229</pre>
7230
7231<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7232<p>The '<tt>llvm.pow.*</tt>' intrinsics return the first operand raised to the
7233 specified (positive or negative) power.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7234
7235<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7236<p>The second argument is a floating point power, and the first is a value to
7237 raise to that power.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7238
7239<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7240<p>This function returns the first value raised to the second power, returning
7241 the same values as the libm <tt>pow</tt> functions would, and handles error
7242 conditions in the same way.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7243
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7244</div>
7245
Dan Gohman4e9011c2011-05-23 21:13:03 +0000[diff] [blame]7246<!-- _______________________________________________________________________ -->
7247<h4>
7248 <a name="int_exp">'<tt>llvm.exp.*</tt>' Intrinsic</a>
7249</h4>
7250
7251<div>
7252
7253<h5>Syntax:</h5>
7254<p>This is an overloaded intrinsic. You can use <tt>llvm.exp</tt> on any
7255 floating point or vector of floating point type. Not all targets support all
7256 types however.</p>
7257
7258<pre>
7259 declare float @llvm.exp.f32(float %Val)
7260 declare double @llvm.exp.f64(double %Val)
7261 declare x86_fp80 @llvm.exp.f80(x86_fp80 %Val)
7262 declare fp128 @llvm.exp.f128(fp128 %Val)
7263 declare ppc_fp128 @llvm.exp.ppcf128(ppc_fp128 %Val)
7264</pre>
7265
7266<h5>Overview:</h5>
7267<p>The '<tt>llvm.exp.*</tt>' intrinsics perform the exp function.</p>
7268
7269<h5>Arguments:</h5>
7270<p>The argument and return value are floating point numbers of the same
7271 type.</p>
7272
7273<h5>Semantics:</h5>
7274<p>This function returns the same values as the libm <tt>exp</tt> functions
7275 would, and handles error conditions in the same way.</p>
7276
7277</div>
7278
7279<!-- _______________________________________________________________________ -->
7280<h4>
7281 <a name="int_log">'<tt>llvm.log.*</tt>' Intrinsic</a>
7282</h4>
7283
7284<div>
7285
7286<h5>Syntax:</h5>
7287<p>This is an overloaded intrinsic. You can use <tt>llvm.log</tt> on any
7288 floating point or vector of floating point type. Not all targets support all
7289 types however.</p>
7290
7291<pre>
7292 declare float @llvm.log.f32(float %Val)
7293 declare double @llvm.log.f64(double %Val)
7294 declare x86_fp80 @llvm.log.f80(x86_fp80 %Val)
7295 declare fp128 @llvm.log.f128(fp128 %Val)
7296 declare ppc_fp128 @llvm.log.ppcf128(ppc_fp128 %Val)
7297</pre>
7298
7299<h5>Overview:</h5>
7300<p>The '<tt>llvm.log.*</tt>' intrinsics perform the log function.</p>
7301
7302<h5>Arguments:</h5>
7303<p>The argument and return value are floating point numbers of the same
7304 type.</p>
7305
7306<h5>Semantics:</h5>
7307<p>This function returns the same values as the libm <tt>log</tt> functions
7308 would, and handles error conditions in the same way.</p>
7309
Nick Lewycky1c929be2011-10-31 01:32:21 +0000[diff] [blame]7310</div>
7311
7312<!-- _______________________________________________________________________ -->
Cameron Zwarich33390842011-07-08 21:39:21 +0000[diff] [blame]7313<h4>
7314 <a name="int_fma">'<tt>llvm.fma.*</tt>' Intrinsic</a>
7315</h4>
7316
7317<div>
7318
7319<h5>Syntax:</h5>
7320<p>This is an overloaded intrinsic. You can use <tt>llvm.fma</tt> on any
7321 floating point or vector of floating point type. Not all targets support all
7322 types however.</p>
7323
7324<pre>
7325 declare float @llvm.fma.f32(float %a, float %b, float %c)
7326 declare double @llvm.fma.f64(double %a, double %b, double %c)
7327 declare x86_fp80 @llvm.fma.f80(x86_fp80 %a, x86_fp80 %b, x86_fp80 %c)
7328 declare fp128 @llvm.fma.f128(fp128 %a, fp128 %b, fp128 %c)
7329 declare ppc_fp128 @llvm.fma.ppcf128(ppc_fp128 %a, ppc_fp128 %b, ppc_fp128 %c)
7330</pre>
7331
7332<h5>Overview:</h5>
Cameron Zwarichabc43e62011-07-08 22:13:55 +0000[diff] [blame]7333<p>The '<tt>llvm.fma.*</tt>' intrinsics perform the fused multiply-add
Cameron Zwarich33390842011-07-08 21:39:21 +0000[diff] [blame]7334 operation.</p>
7335
7336<h5>Arguments:</h5>
7337<p>The argument and return value are floating point numbers of the same
7338 type.</p>
7339
7340<h5>Semantics:</h5>
7341<p>This function returns the same values as the libm <tt>fma</tt> functions
7342 would.</p>
7343
Dan Gohman4e9011c2011-05-23 21:13:03 +0000[diff] [blame]7344</div>
7345
NAKAMURA Takumi4b2e07a2011-10-31 13:04:26 +0000[diff] [blame]7346</div>
7347
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7348<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7349<h3>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]7350 <a name="int_manip">Bit Manipulation Intrinsics</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7351</h3>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7352
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7353<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7354
7355<p>LLVM provides intrinsics for a few important bit manipulation operations.
7356 These allow efficient code generation for some algorithms.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7357
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7358<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7359<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]7360 <a name="int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7361</h4>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]7362
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7363<div>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]7364
7365<h5>Syntax:</h5>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]7366<p>This is an overloaded intrinsic function. You can use bswap on any integer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7367 type that is an even number of bytes (i.e. BitWidth % 16 == 0).</p>
7368
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]7369<pre>
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]7370 declare i16 @llvm.bswap.i16(i16 &lt;id&gt;)
7371 declare i32 @llvm.bswap.i32(i32 &lt;id&gt;)
7372 declare i64 @llvm.bswap.i64(i64 &lt;id&gt;)
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]7373</pre>
7374
7375<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7376<p>The '<tt>llvm.bswap</tt>' family of intrinsics is used to byte swap integer
7377 values with an even number of bytes (positive multiple of 16 bits). These
7378 are useful for performing operations on data that is not in the target's
7379 native byte order.</p>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]7380
7381<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7382<p>The <tt>llvm.bswap.i16</tt> intrinsic returns an i16 value that has the high
7383 and low byte of the input i16 swapped. Similarly,
7384 the <tt>llvm.bswap.i32</tt> intrinsic returns an i32 value that has the four
7385 bytes of the input i32 swapped, so that if the input bytes are numbered 0, 1,
7386 2, 3 then the returned i32 will have its bytes in 3, 2, 1, 0 order.
7387 The <tt>llvm.bswap.i48</tt>, <tt>llvm.bswap.i64</tt> and other intrinsics
7388 extend this concept to additional even-byte lengths (6 bytes, 8 bytes and
7389 more, respectively).</p>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]7390
7391</div>
7392
7393<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7394<h4>
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]7395 <a name="int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7396</h4>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7397
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7398<div>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7399
7400<h5>Syntax:</h5>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]7401<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]7402 width, or on any vector with integer elements. Not all targets support all
7403 bit widths or vector types, however.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7404
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7405<pre>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7406 declare i8 @llvm.ctpop.i8(i8 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]7407 declare i16 @llvm.ctpop.i16(i16 &lt;src&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]7408 declare i32 @llvm.ctpop.i32(i32 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]7409 declare i64 @llvm.ctpop.i64(i64 &lt;src&gt;)
7410 declare i256 @llvm.ctpop.i256(i256 &lt;src&gt;)
Owen Andersonf1ac4652011-07-01 21:52:38 +0000[diff] [blame]7411 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]7412</pre>
7413
7414<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7415<p>The '<tt>llvm.ctpop</tt>' family of intrinsics counts the number of bits set
7416 in a value.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7417
7418<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7419<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]7420 integer type, or a vector with integer elements.
7421 The return type must match the argument type.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7422
7423<h5>Semantics:</h5>
Owen Andersonf1ac4652011-07-01 21:52:38 +0000[diff] [blame]7424<p>The '<tt>llvm.ctpop</tt>' intrinsic counts the 1's in a variable, or within each
7425 element of a vector.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7426
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7427</div>
7428
7429<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7430<h4>
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]7431 <a name="int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7432</h4>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7433
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7434<div>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7435
7436<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7437<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]7438 integer bit width, or any vector whose elements are integers. Not all
7439 targets support all bit widths or vector types, however.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7440
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7441<pre>
Chandler Carruth48b0bbf2011-12-12 04:36:04 +0000[diff] [blame]7442 declare i8 @llvm.ctlz.i8 (i8 &lt;src&gt;, i1 &lt;is_zero_undef&gt;)
7443 declare i16 @llvm.ctlz.i16 (i16 &lt;src&gt;, i1 &lt;is_zero_undef&gt;)
7444 declare i32 @llvm.ctlz.i32 (i32 &lt;src&gt;, i1 &lt;is_zero_undef&gt;)
7445 declare i64 @llvm.ctlz.i64 (i64 &lt;src&gt;, i1 &lt;is_zero_undef&gt;)
7446 declare i256 @llvm.ctlz.i256(i256 &lt;src&gt;, i1 &lt;is_zero_undef&gt;)
7447 declase &lt;2 x i32&gt; @llvm.ctlz.v2i32(&lt;2 x i32&gt; &lt;src&gt;, i1 &lt;is_zero_undef&gt;)
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7448</pre>
7449
7450<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7451<p>The '<tt>llvm.ctlz</tt>' family of intrinsic functions counts the number of
7452 leading zeros in a variable.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7453
7454<h5>Arguments:</h5>
Chandler Carruth48b0bbf2011-12-12 04:36:04 +0000[diff] [blame]7455<p>The first argument is the value to be counted. This argument may be of any
7456 integer type, or a vectory with integer element type. The return type
7457 must match the first argument type.</p>
7458
7459<p>The second argument must be a constant and is a flag to indicate whether the
7460 intrinsic should ensure that a zero as the first argument produces a defined
7461 result. Historically some architectures did not provide a defined result for
7462 zero values as efficiently, and many algorithms are now predicated on
7463 avoiding zero-value inputs.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7464
7465<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7466<p>The '<tt>llvm.ctlz</tt>' intrinsic counts the leading (most significant)
Chandler Carruth48b0bbf2011-12-12 04:36:04 +0000[diff] [blame]7467 zeros in a variable, or within each element of the vector.
7468 If <tt>src == 0</tt> then the result is the size in bits of the type of
7469 <tt>src</tt> if <tt>is_zero_undef == 0</tt> and <tt>undef</tt> otherwise.
7470 For example, <tt>llvm.ctlz(i32 2) = 30</tt>.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7471
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7472</div>
Chris Lattner32006282004-06-11 02:28:03 +0000[diff] [blame]7473
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]7474<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7475<h4>
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]7476 <a name="int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7477</h4>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]7478
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7479<div>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]7480
7481<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7482<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]7483 integer bit width, or any vector of integer elements. Not all targets
7484 support all bit widths or vector types, however.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7485
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]7486<pre>
Chandler Carruth48b0bbf2011-12-12 04:36:04 +0000[diff] [blame]7487 declare i8 @llvm.cttz.i8 (i8 &lt;src&gt;, i1 &lt;is_zero_undef&gt;)
7488 declare i16 @llvm.cttz.i16 (i16 &lt;src&gt;, i1 &lt;is_zero_undef&gt;)
7489 declare i32 @llvm.cttz.i32 (i32 &lt;src&gt;, i1 &lt;is_zero_undef&gt;)
7490 declare i64 @llvm.cttz.i64 (i64 &lt;src&gt;, i1 &lt;is_zero_undef&gt;)
7491 declare i256 @llvm.cttz.i256(i256 &lt;src&gt;, i1 &lt;is_zero_undef&gt;)
7492 declase &lt;2 x i32&gt; @llvm.cttz.v2i32(&lt;2 x i32&gt; &lt;src&gt;, i1 &lt;is_zero_undef&gt;)
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]7493</pre>
7494
7495<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7496<p>The '<tt>llvm.cttz</tt>' family of intrinsic functions counts the number of
7497 trailing zeros.</p>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]7498
7499<h5>Arguments:</h5>
Chandler Carruth48b0bbf2011-12-12 04:36:04 +0000[diff] [blame]7500<p>The first argument is the value to be counted. This argument may be of any
7501 integer type, or a vectory with integer element type. The return type
7502 must match the first argument type.</p>
7503
7504<p>The second argument must be a constant and is a flag to indicate whether the
7505 intrinsic should ensure that a zero as the first argument produces a defined
7506 result. Historically some architectures did not provide a defined result for
7507 zero values as efficiently, and many algorithms are now predicated on
7508 avoiding zero-value inputs.</p>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]7509
7510<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7511<p>The '<tt>llvm.cttz</tt>' intrinsic counts the trailing (least significant)
Owen Andersonf1ac4652011-07-01 21:52:38 +0000[diff] [blame]7512 zeros in a variable, or within each element of a vector.
Chandler Carruth48b0bbf2011-12-12 04:36:04 +0000[diff] [blame]7513 If <tt>src == 0</tt> then the result is the size in bits of the type of
7514 <tt>src</tt> if <tt>is_zero_undef == 0</tt> and <tt>undef</tt> otherwise.
7515 For example, <tt>llvm.cttz(2) = 1</tt>.</p>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]7516
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]7517</div>
7518
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7519</div>
7520
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]7521<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7522<h3>
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]7523 <a name="int_overflow">Arithmetic with Overflow Intrinsics</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7524</h3>
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]7525
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7526<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7527
7528<p>LLVM provides intrinsics for some arithmetic with overflow operations.</p>
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]7529
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7530<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7531<h4>
7532 <a name="int_sadd_overflow">
7533 '<tt>llvm.sadd.with.overflow.*</tt>' Intrinsics
7534 </a>
7535</h4>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7536
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7537<div>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7538
7539<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7540<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]7541 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7542
7543<pre>
7544 declare {i16, i1} @llvm.sadd.with.overflow.i16(i16 %a, i16 %b)
7545 declare {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
7546 declare {i64, i1} @llvm.sadd.with.overflow.i64(i64 %a, i64 %b)
7547</pre>
7548
7549<h5>Overview:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7550<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7551 a signed addition of the two arguments, and indicate whether an overflow
7552 occurred during the signed summation.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7553
7554<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7555<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]7556 be of integer types of any bit width, but they must have the same bit
7557 width. The second element of the result structure must be of
7558 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
7559 undergo signed addition.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7560
7561<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7562<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7563 a signed addition of the two variables. They return a structure &mdash; the
7564 first element of which is the signed summation, and the second element of
7565 which is a bit specifying if the signed summation resulted in an
7566 overflow.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7567
7568<h5>Examples:</h5>
7569<pre>
7570 %res = call {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
7571 %sum = extractvalue {i32, i1} %res, 0
7572 %obit = extractvalue {i32, i1} %res, 1
7573 br i1 %obit, label %overflow, label %normal
7574</pre>
7575
7576</div>
7577
7578<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7579<h4>
7580 <a name="int_uadd_overflow">
7581 '<tt>llvm.uadd.with.overflow.*</tt>' Intrinsics
7582 </a>
7583</h4>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7584
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7585<div>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7586
7587<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7588<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]7589 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7590
7591<pre>
7592 declare {i16, i1} @llvm.uadd.with.overflow.i16(i16 %a, i16 %b)
7593 declare {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
7594 declare {i64, i1} @llvm.uadd.with.overflow.i64(i64 %a, i64 %b)
7595</pre>
7596
7597<h5>Overview:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7598<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7599 an unsigned addition of the two arguments, and indicate whether a carry
7600 occurred during the unsigned summation.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7601
7602<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7603<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]7604 be of integer types of any bit width, but they must have the same bit
7605 width. The second element of the result structure must be of
7606 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
7607 undergo unsigned addition.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7608
7609<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7610<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7611 an unsigned addition of the two arguments. They return a structure &mdash;
7612 the first element of which is the sum, and the second element of which is a
7613 bit specifying if the unsigned summation resulted in a carry.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7614
7615<h5>Examples:</h5>
7616<pre>
7617 %res = call {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
7618 %sum = extractvalue {i32, i1} %res, 0
7619 %obit = extractvalue {i32, i1} %res, 1
7620 br i1 %obit, label %carry, label %normal
7621</pre>
7622
7623</div>
7624
7625<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7626<h4>
7627 <a name="int_ssub_overflow">
7628 '<tt>llvm.ssub.with.overflow.*</tt>' Intrinsics
7629 </a>
7630</h4>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7631
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7632<div>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7633
7634<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7635<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]7636 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7637
7638<pre>
7639 declare {i16, i1} @llvm.ssub.with.overflow.i16(i16 %a, i16 %b)
7640 declare {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
7641 declare {i64, i1} @llvm.ssub.with.overflow.i64(i64 %a, i64 %b)
7642</pre>
7643
7644<h5>Overview:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7645<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7646 a signed subtraction of the two arguments, and indicate whether an overflow
7647 occurred during the signed subtraction.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7648
7649<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7650<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]7651 be of integer types of any bit width, but they must have the same bit
7652 width. The second element of the result structure must be of
7653 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
7654 undergo signed subtraction.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7655
7656<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7657<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7658 a signed subtraction of the two arguments. They return a structure &mdash;
7659 the first element of which is the subtraction, and the second element of
7660 which is a bit specifying if the signed subtraction resulted in an
7661 overflow.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7662
7663<h5>Examples:</h5>
7664<pre>
7665 %res = call {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
7666 %sum = extractvalue {i32, i1} %res, 0
7667 %obit = extractvalue {i32, i1} %res, 1
7668 br i1 %obit, label %overflow, label %normal
7669</pre>
7670
7671</div>
7672
7673<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7674<h4>
7675 <a name="int_usub_overflow">
7676 '<tt>llvm.usub.with.overflow.*</tt>' Intrinsics
7677 </a>
7678</h4>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7679
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7680<div>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7681
7682<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7683<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]7684 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7685
7686<pre>
7687 declare {i16, i1} @llvm.usub.with.overflow.i16(i16 %a, i16 %b)
7688 declare {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
7689 declare {i64, i1} @llvm.usub.with.overflow.i64(i64 %a, i64 %b)
7690</pre>
7691
7692<h5>Overview:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7693<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7694 an unsigned subtraction of the two arguments, and indicate whether an
7695 overflow occurred during the unsigned subtraction.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7696
7697<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7698<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]7699 be of integer types of any bit width, but they must have the same bit
7700 width. The second element of the result structure must be of
7701 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
7702 undergo unsigned subtraction.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7703
7704<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7705<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7706 an unsigned subtraction of the two arguments. They return a structure &mdash;
7707 the first element of which is the subtraction, and the second element of
7708 which is a bit specifying if the unsigned subtraction resulted in an
7709 overflow.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7710
7711<h5>Examples:</h5>
7712<pre>
7713 %res = call {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
7714 %sum = extractvalue {i32, i1} %res, 0
7715 %obit = extractvalue {i32, i1} %res, 1
7716 br i1 %obit, label %overflow, label %normal
7717</pre>
7718
7719</div>
7720
7721<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7722<h4>
7723 <a name="int_smul_overflow">
7724 '<tt>llvm.smul.with.overflow.*</tt>' Intrinsics
7725 </a>
7726</h4>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7727
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7728<div>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7729
7730<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7731<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]7732 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7733
7734<pre>
7735 declare {i16, i1} @llvm.smul.with.overflow.i16(i16 %a, i16 %b)
7736 declare {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
7737 declare {i64, i1} @llvm.smul.with.overflow.i64(i64 %a, i64 %b)
7738</pre>
7739
7740<h5>Overview:</h5>
7741
7742<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7743 a signed multiplication of the two arguments, and indicate whether an
7744 overflow occurred during the signed multiplication.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7745
7746<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7747<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]7748 be of integer types of any bit width, but they must have the same bit
7749 width. The second element of the result structure must be of
7750 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
7751 undergo signed multiplication.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7752
7753<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7754<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7755 a signed multiplication of the two arguments. They return a structure &mdash;
7756 the first element of which is the multiplication, and the second element of
7757 which is a bit specifying if the signed multiplication resulted in an
7758 overflow.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7759
7760<h5>Examples:</h5>
7761<pre>
7762 %res = call {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
7763 %sum = extractvalue {i32, i1} %res, 0
7764 %obit = extractvalue {i32, i1} %res, 1
7765 br i1 %obit, label %overflow, label %normal
7766</pre>
7767
Reid Spencerf86037f2007-04-11 23:23:49 +0000[diff] [blame]7768</div>
7769
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]7770<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7771<h4>
7772 <a name="int_umul_overflow">
7773 '<tt>llvm.umul.with.overflow.*</tt>' Intrinsics
7774 </a>
7775</h4>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]7776
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7777<div>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]7778
7779<h5>Syntax:</h5>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]7780<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]7781 on any integer bit width.</p>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]7782
7783<pre>
7784 declare {i16, i1} @llvm.umul.with.overflow.i16(i16 %a, i16 %b)
7785 declare {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
7786 declare {i64, i1} @llvm.umul.with.overflow.i64(i64 %a, i64 %b)
7787</pre>
7788
7789<h5>Overview:</h5>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]7790<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7791 a unsigned multiplication of the two arguments, and indicate whether an
7792 overflow occurred during the unsigned multiplication.</p>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]7793
7794<h5>Arguments:</h5>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]7795<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]7796 be of integer types of any bit width, but they must have the same bit
7797 width. The second element of the result structure must be of
7798 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
7799 undergo unsigned multiplication.</p>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]7800
7801<h5>Semantics:</h5>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]7802<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7803 an unsigned multiplication of the two arguments. They return a structure
7804 &mdash; the first element of which is the multiplication, and the second
7805 element of which is a bit specifying if the unsigned multiplication resulted
7806 in an overflow.</p>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]7807
7808<h5>Examples:</h5>
7809<pre>
7810 %res = call {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
7811 %sum = extractvalue {i32, i1} %res, 0
7812 %obit = extractvalue {i32, i1} %res, 1
7813 br i1 %obit, label %overflow, label %normal
7814</pre>
7815
7816</div>
7817
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7818</div>
7819
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]7820<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7821<h3>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]7822 <a name="int_fp16">Half Precision Floating Point Intrinsics</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7823</h3>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]7824
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7825<div>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]7826
Chris Lattner0cec9c82010-03-15 04:12:21 +0000[diff] [blame]7827<p>Half precision floating point is a storage-only format. This means that it is
7828 a dense encoding (in memory) but does not support computation in the
7829 format.</p>
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]7830
Chris Lattner0cec9c82010-03-15 04:12:21 +0000[diff] [blame]7831<p>This means that code must first load the half-precision floating point
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]7832 value as an i16, then convert it to float with <a
7833 href="#int_convert_from_fp16"><tt>llvm.convert.from.fp16</tt></a>.
7834 Computation can then be performed on the float value (including extending to
Chris Lattner0cec9c82010-03-15 04:12:21 +0000[diff] [blame]7835 double etc). To store the value back to memory, it is first converted to
7836 float if needed, then converted to i16 with
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]7837 <a href="#int_convert_to_fp16"><tt>llvm.convert.to.fp16</tt></a>, then
7838 storing as an i16 value.</p>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]7839
7840<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7841<h4>
7842 <a name="int_convert_to_fp16">
7843 '<tt>llvm.convert.to.fp16</tt>' Intrinsic
7844 </a>
7845</h4>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]7846
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7847<div>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]7848
7849<h5>Syntax:</h5>
7850<pre>
7851 declare i16 @llvm.convert.to.fp16(f32 %a)
7852</pre>
7853
7854<h5>Overview:</h5>
7855<p>The '<tt>llvm.convert.to.fp16</tt>' intrinsic function performs
7856 a conversion from single precision floating point format to half precision
7857 floating point format.</p>
7858
7859<h5>Arguments:</h5>
7860<p>The intrinsic function contains single argument - the value to be
7861 converted.</p>
7862
7863<h5>Semantics:</h5>
7864<p>The '<tt>llvm.convert.to.fp16</tt>' intrinsic function performs
7865 a conversion from single precision floating point format to half precision
Chris Lattner0cec9c82010-03-15 04:12:21 +0000[diff] [blame]7866 floating point format. The return value is an <tt>i16</tt> which
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]7867 contains the converted number.</p>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]7868
7869<h5>Examples:</h5>
7870<pre>
7871 %res = call i16 @llvm.convert.to.fp16(f32 %a)
7872 store i16 %res, i16* @x, align 2
7873</pre>
7874
7875</div>
7876
7877<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7878<h4>
7879 <a name="int_convert_from_fp16">
7880 '<tt>llvm.convert.from.fp16</tt>' Intrinsic
7881 </a>
7882</h4>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]7883
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7884<div>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]7885
7886<h5>Syntax:</h5>
7887<pre>
7888 declare f32 @llvm.convert.from.fp16(i16 %a)
7889</pre>
7890
7891<h5>Overview:</h5>
7892<p>The '<tt>llvm.convert.from.fp16</tt>' intrinsic function performs
7893 a conversion from half precision floating point format to single precision
7894 floating point format.</p>
7895
7896<h5>Arguments:</h5>
7897<p>The intrinsic function contains single argument - the value to be
7898 converted.</p>
7899
7900<h5>Semantics:</h5>
7901<p>The '<tt>llvm.convert.from.fp16</tt>' intrinsic function performs a
Chris Lattner0cec9c82010-03-15 04:12:21 +0000[diff] [blame]7902 conversion from half single precision floating point format to single
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]7903 precision floating point format. The input half-float value is represented by
7904 an <tt>i16</tt> value.</p>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]7905
7906<h5>Examples:</h5>
7907<pre>
7908 %a = load i16* @x, align 2
7909 %res = call f32 @llvm.convert.from.fp16(i16 %a)
7910</pre>
7911
7912</div>
7913
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7914</div>
7915
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]7916<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7917<h3>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]7918 <a name="int_debugger">Debugger Intrinsics</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7919</h3>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]7920
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7921<div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]7922
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7923<p>The LLVM debugger intrinsics (which all start with <tt>llvm.dbg.</tt>
7924 prefix), are described in
7925 the <a href="SourceLevelDebugging.html#format_common_intrinsics">LLVM Source
7926 Level Debugging</a> document.</p>
7927
7928</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]7929
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]7930<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7931<h3>
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]7932 <a name="int_eh">Exception Handling Intrinsics</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7933</h3>
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]7934
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7935<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7936
7937<p>The LLVM exception handling intrinsics (which all start with
7938 <tt>llvm.eh.</tt> prefix), are described in
7939 the <a href="ExceptionHandling.html#format_common_intrinsics">LLVM Exception
7940 Handling</a> document.</p>
7941
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]7942</div>
7943
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]7944<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7945<h3>
Duncan Sands4a544a72011-09-06 13:37:06 +0000[diff] [blame]7946 <a name="int_trampoline">Trampoline Intrinsics</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7947</h3>
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]7948
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7949<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7950
Duncan Sands4a544a72011-09-06 13:37:06 +0000[diff] [blame]7951<p>These intrinsics make it possible to excise one parameter, marked with
Dan Gohmanff235352010-07-02 23:18:08 +0000[diff] [blame]7952 the <a href="#nest"><tt>nest</tt></a> attribute, from a function.
7953 The result is a callable
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7954 function pointer lacking the nest parameter - the caller does not need to
7955 provide a value for it. Instead, the value to use is stored in advance in a
7956 "trampoline", a block of memory usually allocated on the stack, which also
7957 contains code to splice the nest value into the argument list. This is used
7958 to implement the GCC nested function address extension.</p>
7959
7960<p>For example, if the function is
7961 <tt>i32 f(i8* nest %c, i32 %x, i32 %y)</tt> then the resulting function
7962 pointer has signature <tt>i32 (i32, i32)*</tt>. It can be created as
7963 follows:</p>
7964
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]7965<pre class="doc_code">
Duncan Sandsf7331b32007-09-11 14:10:23 +0000[diff] [blame]7966 %tramp = alloca [10 x i8], align 4 ; size and alignment only correct for X86
7967 %tramp1 = getelementptr [10 x i8]* %tramp, i32 0, i32 0
Duncan Sands4a544a72011-09-06 13:37:06 +0000[diff] [blame]7968 call i8* @llvm.init.trampoline(i8* %tramp1, i8* bitcast (i32 (i8*, i32, i32)* @f to i8*), i8* %nval)
7969 %p = call i8* @llvm.adjust.trampoline(i8* %tramp1)
Duncan Sandsf7331b32007-09-11 14:10:23 +0000[diff] [blame]7970 %fp = bitcast i8* %p to i32 (i32, i32)*
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]7971</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7972
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7973<p>The call <tt>%val = call i32 %fp(i32 %x, i32 %y)</tt> is then equivalent
7974 to <tt>%val = call i32 %f(i8* %nval, i32 %x, i32 %y)</tt>.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7975
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]7976<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7977<h4>
7978 <a name="int_it">
7979 '<tt>llvm.init.trampoline</tt>' Intrinsic
7980 </a>
7981</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7982
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7983<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7984
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]7985<h5>Syntax:</h5>
7986<pre>
Duncan Sands4a544a72011-09-06 13:37:06 +0000[diff] [blame]7987 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]7988</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7989
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]7990<h5>Overview:</h5>
Duncan Sands4a544a72011-09-06 13:37:06 +0000[diff] [blame]7991<p>This fills the memory pointed to by <tt>tramp</tt> with executable code,
7992 turning it into a trampoline.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7993
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]7994<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7995<p>The <tt>llvm.init.trampoline</tt> intrinsic takes three arguments, all
7996 pointers. The <tt>tramp</tt> argument must point to a sufficiently large and
7997 sufficiently aligned block of memory; this memory is written to by the
7998 intrinsic. Note that the size and the alignment are target-specific - LLVM
7999 currently provides no portable way of determining them, so a front-end that
8000 generates this intrinsic needs to have some target-specific knowledge.
8001 The <tt>func</tt> argument must hold a function bitcast to
8002 an <tt>i8*</tt>.</p>
8003
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]8004<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8005<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]8006 dependent code, turning it into a function. Then <tt>tramp</tt> needs to be
8007 passed to <a href="#int_at">llvm.adjust.trampoline</a> to get a pointer
8008 which can be <a href="#int_trampoline">bitcast (to a new function) and
8009 called</a>. The new function's signature is the same as that of
8010 <tt>func</tt> with any arguments marked with the <tt>nest</tt> attribute
8011 removed. At most one such <tt>nest</tt> argument is allowed, and it must be of
8012 pointer type. Calling the new function is equivalent to calling <tt>func</tt>
8013 with the same argument list, but with <tt>nval</tt> used for the missing
8014 <tt>nest</tt> argument. If, after calling <tt>llvm.init.trampoline</tt>, the
8015 memory pointed to by <tt>tramp</tt> is modified, then the effect of any later call
8016 to the returned function pointer is undefined.</p>
8017</div>
8018
8019<!-- _______________________________________________________________________ -->
8020<h4>
8021 <a name="int_at">
8022 '<tt>llvm.adjust.trampoline</tt>' Intrinsic
8023 </a>
8024</h4>
8025
8026<div>
8027
8028<h5>Syntax:</h5>
8029<pre>
8030 declare i8* @llvm.adjust.trampoline(i8* &lt;tramp&gt;)
8031</pre>
8032
8033<h5>Overview:</h5>
8034<p>This performs any required machine-specific adjustment to the address of a
8035 trampoline (passed as <tt>tramp</tt>).</p>
8036
8037<h5>Arguments:</h5>
8038<p><tt>tramp</tt> must point to a block of memory which already has trampoline code
8039 filled in by a previous call to <a href="#int_it"><tt>llvm.init.trampoline</tt>
8040 </a>.</p>
8041
8042<h5>Semantics:</h5>
8043<p>On some architectures the address of the code to be executed needs to be
8044 different to the address where the trampoline is actually stored. This
8045 intrinsic returns the executable address corresponding to <tt>tramp</tt>
8046 after performing the required machine specific adjustments.
8047 The pointer returned can then be <a href="#int_trampoline"> bitcast and
8048 executed</a>.
8049</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8050
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]8051</div>
8052
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8053</div>
8054
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]8055<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8056<h3>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]8057 <a name="int_memorymarkers">Memory Use Markers</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8058</h3>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]8059
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8060<div>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]8061
8062<p>This class of intrinsics exists to information about the lifetime of memory
8063 objects and ranges where variables are immutable.</p>
8064
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]8065<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8066<h4>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]8067 <a name="int_lifetime_start">'<tt>llvm.lifetime.start</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8068</h4>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]8069
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8070<div>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]8071
8072<h5>Syntax:</h5>
8073<pre>
8074 declare void @llvm.lifetime.start(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
8075</pre>
8076
8077<h5>Overview:</h5>
8078<p>The '<tt>llvm.lifetime.start</tt>' intrinsic specifies the start of a memory
8079 object's lifetime.</p>
8080
8081<h5>Arguments:</h5>
Nick Lewycky321333e2009-10-13 07:57:33 +0000[diff] [blame]8082<p>The first argument is a constant integer representing the size of the
8083 object, or -1 if it is variable sized. The second argument is a pointer to
8084 the object.</p>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]8085
8086<h5>Semantics:</h5>
8087<p>This intrinsic indicates that before this point in the code, the value of the
8088 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]8089 never be used and has an undefined value. A load from the pointer that
8090 precedes this intrinsic can be replaced with
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]8091 <tt>'<a href="#undefvalues">undef</a>'</tt>.</p>
8092
8093</div>
8094
8095<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8096<h4>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]8097 <a name="int_lifetime_end">'<tt>llvm.lifetime.end</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8098</h4>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]8099
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8100<div>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]8101
8102<h5>Syntax:</h5>
8103<pre>
8104 declare void @llvm.lifetime.end(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
8105</pre>
8106
8107<h5>Overview:</h5>
8108<p>The '<tt>llvm.lifetime.end</tt>' intrinsic specifies the end of a memory
8109 object's lifetime.</p>
8110
8111<h5>Arguments:</h5>
Nick Lewycky321333e2009-10-13 07:57:33 +0000[diff] [blame]8112<p>The first argument is a constant integer representing the size of the
8113 object, or -1 if it is variable sized. The second argument is a pointer to
8114 the object.</p>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]8115
8116<h5>Semantics:</h5>
8117<p>This intrinsic indicates that after this point in the code, the value of the
8118 memory pointed to by <tt>ptr</tt> is dead. This means that it is known to
8119 never be used and has an undefined value. Any stores into the memory object
8120 following this intrinsic may be removed as dead.
8121
8122</div>
8123
8124<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8125<h4>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]8126 <a name="int_invariant_start">'<tt>llvm.invariant.start</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8127</h4>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]8128
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8129<div>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]8130
8131<h5>Syntax:</h5>
8132<pre>
Nick Lewycky29b6cb42010-11-30 04:13:41 +0000[diff] [blame]8133 declare {}* @llvm.invariant.start(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]8134</pre>
8135
8136<h5>Overview:</h5>
8137<p>The '<tt>llvm.invariant.start</tt>' intrinsic specifies that the contents of
8138 a memory object will not change.</p>
8139
8140<h5>Arguments:</h5>
Nick Lewycky321333e2009-10-13 07:57:33 +0000[diff] [blame]8141<p>The first argument is a constant integer representing the size of the
8142 object, or -1 if it is variable sized. The second argument is a pointer to
8143 the object.</p>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]8144
8145<h5>Semantics:</h5>
8146<p>This intrinsic indicates that until an <tt>llvm.invariant.end</tt> that uses
8147 the return value, the referenced memory location is constant and
8148 unchanging.</p>
8149
8150</div>
8151
8152<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8153<h4>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]8154 <a name="int_invariant_end">'<tt>llvm.invariant.end</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8155</h4>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]8156
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8157<div>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]8158
8159<h5>Syntax:</h5>
8160<pre>
8161 declare void @llvm.invariant.end({}* &lt;start&gt;, i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
8162</pre>
8163
8164<h5>Overview:</h5>
8165<p>The '<tt>llvm.invariant.end</tt>' intrinsic specifies that the contents of
8166 a memory object are mutable.</p>
8167
8168<h5>Arguments:</h5>
8169<p>The first argument is the matching <tt>llvm.invariant.start</tt> intrinsic.
Nick Lewycky321333e2009-10-13 07:57:33 +0000[diff] [blame]8170 The second argument is a constant integer representing the size of the
8171 object, or -1 if it is variable sized and the third argument is a pointer
8172 to the object.</p>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]8173
8174<h5>Semantics:</h5>
8175<p>This intrinsic indicates that the memory is mutable again.</p>
8176
8177</div>
8178
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8179</div>
8180
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]8181<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8182<h3>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]8183 <a name="int_general">General Intrinsics</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8184</h3>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]8185
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8186<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8187
8188<p>This class of intrinsics is designed to be generic and has no specific
8189 purpose.</p>
8190
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]8191<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8192<h4>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]8193 <a name="int_var_annotation">'<tt>llvm.var.annotation</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8194</h4>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]8195
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8196<div>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]8197
8198<h5>Syntax:</h5>
8199<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]8200 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]8201</pre>
8202
8203<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8204<p>The '<tt>llvm.var.annotation</tt>' intrinsic.</p>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]8205
8206<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8207<p>The first argument is a pointer to a value, the second is a pointer to a
8208 global string, the third is a pointer to a global string which is the source
8209 file name, and the last argument is the line number.</p>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]8210
8211<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8212<p>This intrinsic allows annotation of local variables with arbitrary strings.
8213 This can be useful for special purpose optimizations that want to look for
John Criswelle865c032011-08-19 16:57:55 +0000[diff] [blame]8214 these annotations. These have no other defined use; they are ignored by code
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8215 generation and optimization.</p>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]8216
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]8217</div>
8218
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]8219<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8220<h4>
Tanya Lattnere1a8da02007-09-21 23:57:59 +0000[diff] [blame]8221 <a name="int_annotation">'<tt>llvm.annotation.*</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8222</h4>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]8223
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8224<div>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]8225
8226<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8227<p>This is an overloaded intrinsic. You can use '<tt>llvm.annotation</tt>' on
8228 any integer bit width.</p>
8229
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]8230<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]8231 declare i8 @llvm.annotation.i8(i8 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
8232 declare i16 @llvm.annotation.i16(i16 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
8233 declare i32 @llvm.annotation.i32(i32 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
8234 declare i64 @llvm.annotation.i64(i64 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
8235 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]8236</pre>
8237
8238<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8239<p>The '<tt>llvm.annotation</tt>' intrinsic.</p>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]8240
8241<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8242<p>The first argument is an integer value (result of some expression), the
8243 second is a pointer to a global string, the third is a pointer to a global
8244 string which is the source file name, and the last argument is the line
8245 number. It returns the value of the first argument.</p>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]8246
8247<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8248<p>This intrinsic allows annotations to be put on arbitrary expressions with
8249 arbitrary strings. This can be useful for special purpose optimizations that
John Criswelle865c032011-08-19 16:57:55 +0000[diff] [blame]8250 want to look for these annotations. These have no other defined use; they
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8251 are ignored by code generation and optimization.</p>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]8252
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]8253</div>
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]8254
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]8255<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8256<h4>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]8257 <a name="int_trap">'<tt>llvm.trap</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8258</h4>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]8259
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8260<div>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]8261
8262<h5>Syntax:</h5>
8263<pre>
8264 declare void @llvm.trap()
8265</pre>
8266
8267<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8268<p>The '<tt>llvm.trap</tt>' intrinsic.</p>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]8269
8270<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8271<p>None.</p>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]8272
8273<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8274<p>This intrinsics is lowered to the target dependent trap instruction. If the
8275 target does not have a trap instruction, this intrinsic will be lowered to
8276 the call of the <tt>abort()</tt> function.</p>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]8277
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]8278</div>
8279
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]8280<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8281<h4>
Misha Brukmandccb0252008-11-22 23:55:29 +0000[diff] [blame]8282 <a name="int_stackprotector">'<tt>llvm.stackprotector</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8283</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8284
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8285<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8286
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]8287<h5>Syntax:</h5>
8288<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]8289 declare void @llvm.stackprotector(i8* &lt;guard&gt;, i8** &lt;slot&gt;)
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]8290</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8291
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]8292<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8293<p>The <tt>llvm.stackprotector</tt> intrinsic takes the <tt>guard</tt> and
8294 stores it onto the stack at <tt>slot</tt>. The stack slot is adjusted to
8295 ensure that it is placed on the stack before local variables.</p>
8296
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]8297<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8298<p>The <tt>llvm.stackprotector</tt> intrinsic requires two pointer
8299 arguments. The first argument is the value loaded from the stack
8300 guard <tt>@__stack_chk_guard</tt>. The second variable is an <tt>alloca</tt>
8301 that has enough space to hold the value of the guard.</p>
8302
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]8303<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8304<p>This intrinsic causes the prologue/epilogue inserter to force the position of
8305 the <tt>AllocaInst</tt> stack slot to be before local variables on the
8306 stack. This is to ensure that if a local variable on the stack is
8307 overwritten, it will destroy the value of the guard. When the function exits,
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]8308 the guard on the stack is checked against the original guard. If they are
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8309 different, then the program aborts by calling the <tt>__stack_chk_fail()</tt>
8310 function.</p>
8311
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]8312</div>
8313
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]8314<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8315<h4>
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]8316 <a name="int_objectsize">'<tt>llvm.objectsize</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8317</h4>
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]8318
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8319<div>
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]8320
8321<h5>Syntax:</h5>
8322<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]8323 declare i32 @llvm.objectsize.i32(i8* &lt;object&gt;, i1 &lt;type&gt;)
8324 declare i64 @llvm.objectsize.i64(i8* &lt;object&gt;, i1 &lt;type&gt;)
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]8325</pre>
8326
8327<h5>Overview:</h5>
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]8328<p>The <tt>llvm.objectsize</tt> intrinsic is designed to provide information to
8329 the optimizers to determine at compile time whether a) an operation (like
8330 memcpy) will overflow a buffer that corresponds to an object, or b) that a
8331 runtime check for overflow isn't necessary. An object in this context means
8332 an allocation of a specific class, structure, array, or other object.</p>
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]8333
8334<h5>Arguments:</h5>
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]8335<p>The <tt>llvm.objectsize</tt> intrinsic takes two arguments. The first
Eric Christopher8295a0a2009-12-23 00:29:49 +0000[diff] [blame]8336 argument is a pointer to or into the <tt>object</tt>. The second argument
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]8337 is a boolean 0 or 1. This argument determines whether you want the
8338 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]8339 1, variables are not allowed.</p>
8340
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]8341<h5>Semantics:</h5>
8342<p>The <tt>llvm.objectsize</tt> intrinsic is lowered to either a constant
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]8343 representing the size of the object concerned, or <tt>i32/i64 -1 or 0</tt>,
8344 depending on the <tt>type</tt> argument, if the size cannot be determined at
8345 compile time.</p>
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]8346
8347</div>
Jakub Staszakb170e2d2011-12-04 18:29:26 +0000[diff] [blame]8348<!-- _______________________________________________________________________ -->
8349<h4>
8350 <a name="int_expect">'<tt>llvm.expect</tt>' Intrinsic</a>
8351</h4>
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]8352
Jakub Staszakb170e2d2011-12-04 18:29:26 +0000[diff] [blame]8353<div>
8354
8355<h5>Syntax:</h5>
8356<pre>
8357 declare i32 @llvm.expect.i32(i32 &lt;val&gt;, i32 &lt;expected_val&gt;)
8358 declare i64 @llvm.expect.i64(i64 &lt;val&gt;, i64 &lt;expected_val&gt;)
8359</pre>
8360
8361<h5>Overview:</h5>
8362<p>The <tt>llvm.expect</tt> intrinsic provides information about expected (the
8363 most probable) value of <tt>val</tt>, which can be used by optimizers.</p>
8364
8365<h5>Arguments:</h5>
8366<p>The <tt>llvm.expect</tt> intrinsic takes two arguments. The first
8367 argument is a value. The second argument is an expected value, this needs to
8368 be a constant value, variables are not allowed.</p>
8369
8370<h5>Semantics:</h5>
8371<p>This intrinsic is lowered to the <tt>val</tt>.</p>
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8372</div>
8373
8374</div>
8375
Jakub Staszakb170e2d2011-12-04 18:29:26 +0000[diff] [blame]8376</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]8377<!-- *********************************************************************** -->
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]8378<hr>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]8379<address>
8380 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
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Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]8382 <a href="http://validator.w3.org/check/referer"><img
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Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]8384
8385 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
NAKAMURA Takumib9a33632011-04-09 02:13:37 +0000[diff] [blame]8386 <a href="http://llvm.org/">The LLVM Compiler Infrastructure</a><br>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]8387 Last modified: $Date$
8388</address>
Chris Lattnerc7d3ab32008-01-04 04:33:49 +0000[diff] [blame]8389
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]8390</body>
8391</html>