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gerrit-public.fairphone.software / toolchain / llvm-project / b6c2220600720b9be93b8f41a155e2763fb8aec1 / . / llvm / 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">
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Reid Spencercb84e432004-08-26 20:44:00 +0000[diff] [blame]9 content="LLVM Assembly Language Reference Manual.">
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11</head>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]12
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]13<body>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]14
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]15<h1>LLVM Language Reference Manual</h1>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]16<ol>
Misha Brukman76307852003-11-08 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 Lattner6af02f32004-12-09 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 Wendlinga3c6f6b2009-07-20 01:03:30 +0000[diff] [blame]23 <li><a href="#linkage">Linkage Types</a>
24 <ol>
Bill Wendling8693ef82009-07-20 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 Wendling03bcd6e2010-07-01 21:55:59 +0000[diff] [blame]27 <li><a href="#linkage_linker_private_weak">'<tt>linker_private_weak</tt>' Linkage</a></li>
Bill Wendling578ee402010-08-20 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 Wendling8693ef82009-07-20 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 Lattner80d73c72009-10-10 18:26:06 +0000[diff] [blame]36 <li><a href="#linkage_linkonce_odr">'<tt>linkonce_odr</tt>' Linkage</a></li>
Bill Wendling8693ef82009-07-20 02:41:50 +0000[diff] [blame]37 <li><a href="#linkage_weak">'<tt>weak_odr</tt>' Linkage</a></li>
Bill Wendlingb4d076e2011-10-11 06:41:28 +0000[diff] [blame]38 <li><a href="#linkage_external">'<tt>external</tt>' Linkage</a></li>
Bill Wendling8693ef82009-07-20 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 Wendlinga3c6f6b2009-07-20 01:03:30 +0000[diff] [blame]41 </ol>
42 </li>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]43 <li><a href="#callingconv">Calling Conventions</a></li>
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]44 <li><a href="#namedtypes">Named Types</a></li>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]45 <li><a href="#globalvars">Global Variables</a></li>
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]46 <li><a href="#functionstructure">Functions</a></li>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]47 <li><a href="#aliasstructure">Aliases</a></li>
Devang Pateld1a89692010-01-11 19:35:55 +0000[diff] [blame]48 <li><a href="#namedmetadatastructure">Named Metadata</a></li>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]49 <li><a href="#paramattrs">Parameter Attributes</a></li>
Devang Patel9eb525d2008-09-26 23:51:19 +0000[diff] [blame]50 <li><a href="#fnattrs">Function Attributes</a></li>
Gordon Henriksen71183b62007-12-10 03:18:06 +0000[diff] [blame]51 <li><a href="#gc">Garbage Collector Names</a></li>
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]52 <li><a href="#moduleasm">Module-Level Inline Assembly</a></li>
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]53 <li><a href="#datalayout">Data Layout</a></li>
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]54 <li><a href="#pointeraliasing">Pointer Aliasing Rules</a></li>
Jeffrey Yasskin5d284ae2010-04-26 21:21:24 +0000[diff] [blame]55 <li><a href="#volatile">Volatile Memory Accesses</a></li>
Eli Friedman35b54aa2011-07-20 21:35:53 +0000[diff] [blame]56 <li><a href="#memmodel">Memory Model for Concurrent Operations</a></li>
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]57 <li><a href="#ordering">Atomic Memory Ordering Constraints</a></li>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]58 </ol>
59 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]60 <li><a href="#typesystem">Type System</a>
61 <ol>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]62 <li><a href="#t_classifications">Type Classifications</a></li>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]63 <li><a href="#t_primitive">Primitive Types</a>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]64 <ol>
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]65 <li><a href="#t_integer">Integer Type</a></li>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]66 <li><a href="#t_floating">Floating Point Types</a></li>
Dale Johannesen33e5c352010-10-01 00:48:59 +0000[diff] [blame]67 <li><a href="#t_x86mmx">X86mmx Type</a></li>
Chris Lattner7824d182008-01-04 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 Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]70 <li><a href="#t_metadata">Metadata Type</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]71 </ol>
72 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]73 <li><a href="#t_derived">Derived Types</a>
74 <ol>
Chris Lattner392be582010-02-12 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 Lattner2a843822011-07-23 19:59:08 +0000[diff] [blame]79 <li><a href="#t_opaque">Opaque Structure Types</a></li>
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]80 <li><a href="#t_vector">Vector Type</a></li>
81 </ol>
82 </li>
Misha Brukman76307852003-11-08 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 Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]85 </ol>
86 </li>
87 </ol>
88 </li>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]89 <li><a href="#constants">Constants</a>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]90 <ol>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]91 <li><a href="#simpleconstants">Simple Constants</a></li>
Chris Lattner361bfcd2009-02-28 18:32:25 +0000[diff] [blame]92 <li><a href="#complexconstants">Complex Constants</a></li>
Dan Gohmanef9462f2008-10-14 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 Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]95 <li><a href="#trapvalues">Trap Values</a></li>
Chris Lattner2bfd3202009-10-27 21:19:13 +0000[diff] [blame]96 <li><a href="#blockaddress">Addresses of Basic Blocks</a></li>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]97 <li><a href="#constantexprs">Constant Expressions</a></li>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]98 </ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]99 </li>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]100 <li><a href="#othervalues">Other Values</a>
101 <ol>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]102 <li><a href="#inlineasm">Inline Assembler Expressions</a></li>
Peter Collingbourneec9ff672011-10-27 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 Collingbournef7d1e7b2011-10-27 19:19:14 +0000[diff] [blame]106 <li><a href="#fpaccuracy">'<tt>fpaccuracy</tt>' Metadata</a></li>
Peter Collingbourneec9ff672011-10-27 19:19:07 +0000[diff] [blame]107 </ol>
108 </li>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]109 </ol>
110 </li>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]111 <li><a href="#intrinsic_globals">Intrinsic Global Variables</a>
112 <ol>
113 <li><a href="#intg_used">The '<tt>llvm.used</tt>' Global Variable</a></li>
Chris Lattner58f9bb22009-07-20 06:14:25 +0000[diff] [blame]114 <li><a href="#intg_compiler_used">The '<tt>llvm.compiler.used</tt>'
115 Global Variable</a></li>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]116 <li><a href="#intg_global_ctors">The '<tt>llvm.global_ctors</tt>'
117 Global Variable</a></li>
118 <li><a href="#intg_global_dtors">The '<tt>llvm.global_dtors</tt>'
119 Global Variable</a></li>
120 </ol>
121 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]122 <li><a href="#instref">Instruction Reference</a>
123 <ol>
124 <li><a href="#terminators">Terminator Instructions</a>
125 <ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]126 <li><a href="#i_ret">'<tt>ret</tt>' Instruction</a></li>
127 <li><a href="#i_br">'<tt>br</tt>' Instruction</a></li>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]128 <li><a href="#i_switch">'<tt>switch</tt>' Instruction</a></li>
Chris Lattnerd04cb6d2009-10-28 00:19:10 +0000[diff] [blame]129 <li><a href="#i_indirectbr">'<tt>indirectbr</tt>' Instruction</a></li>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]130 <li><a href="#i_invoke">'<tt>invoke</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]131 <li><a href="#i_unwind">'<tt>unwind</tt>' Instruction</a></li>
Bill Wendlingf891bf82011-07-31 06:30:59 +0000[diff] [blame]132 <li><a href="#i_resume">'<tt>resume</tt>' Instruction</a></li>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]133 <li><a href="#i_unreachable">'<tt>unreachable</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]134 </ol>
135 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]136 <li><a href="#binaryops">Binary Operations</a>
137 <ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]138 <li><a href="#i_add">'<tt>add</tt>' Instruction</a></li>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]139 <li><a href="#i_fadd">'<tt>fadd</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]140 <li><a href="#i_sub">'<tt>sub</tt>' Instruction</a></li>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]141 <li><a href="#i_fsub">'<tt>fsub</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]142 <li><a href="#i_mul">'<tt>mul</tt>' Instruction</a></li>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]143 <li><a href="#i_fmul">'<tt>fmul</tt>' Instruction</a></li>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]144 <li><a href="#i_udiv">'<tt>udiv</tt>' Instruction</a></li>
145 <li><a href="#i_sdiv">'<tt>sdiv</tt>' Instruction</a></li>
146 <li><a href="#i_fdiv">'<tt>fdiv</tt>' Instruction</a></li>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]147 <li><a href="#i_urem">'<tt>urem</tt>' Instruction</a></li>
148 <li><a href="#i_srem">'<tt>srem</tt>' Instruction</a></li>
149 <li><a href="#i_frem">'<tt>frem</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]150 </ol>
151 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]152 <li><a href="#bitwiseops">Bitwise Binary Operations</a>
153 <ol>
Reid Spencer2ab01932007-02-02 13:57:07 +0000[diff] [blame]154 <li><a href="#i_shl">'<tt>shl</tt>' Instruction</a></li>
155 <li><a href="#i_lshr">'<tt>lshr</tt>' Instruction</a></li>
156 <li><a href="#i_ashr">'<tt>ashr</tt>' Instruction</a></li>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]157 <li><a href="#i_and">'<tt>and</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]158 <li><a href="#i_or">'<tt>or</tt>' Instruction</a></li>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]159 <li><a href="#i_xor">'<tt>xor</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]160 </ol>
161 </li>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]162 <li><a href="#vectorops">Vector Operations</a>
163 <ol>
164 <li><a href="#i_extractelement">'<tt>extractelement</tt>' Instruction</a></li>
165 <li><a href="#i_insertelement">'<tt>insertelement</tt>' Instruction</a></li>
166 <li><a href="#i_shufflevector">'<tt>shufflevector</tt>' Instruction</a></li>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]167 </ol>
168 </li>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]169 <li><a href="#aggregateops">Aggregate Operations</a>
170 <ol>
171 <li><a href="#i_extractvalue">'<tt>extractvalue</tt>' Instruction</a></li>
172 <li><a href="#i_insertvalue">'<tt>insertvalue</tt>' Instruction</a></li>
173 </ol>
174 </li>
Chris Lattner6ab66722006-08-15 00:45:58 +0000[diff] [blame]175 <li><a href="#memoryops">Memory Access and Addressing Operations</a>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]176 <ol>
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]177 <li><a href="#i_alloca">'<tt>alloca</tt>' Instruction</a></li>
178 <li><a href="#i_load">'<tt>load</tt>' Instruction</a></li>
179 <li><a href="#i_store">'<tt>store</tt>' Instruction</a></li>
180 <li><a href="#i_fence">'<tt>fence</tt>' Instruction</a></li>
181 <li><a href="#i_cmpxchg">'<tt>cmpxchg</tt>' Instruction</a></li>
182 <li><a href="#i_atomicrmw">'<tt>atomicrmw</tt>' Instruction</a></li>
Robert Bocchino820bc75b2006-02-17 21:18:08 +0000[diff] [blame]183 <li><a href="#i_getelementptr">'<tt>getelementptr</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]184 </ol>
185 </li>
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]186 <li><a href="#convertops">Conversion Operations</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]187 <ol>
188 <li><a href="#i_trunc">'<tt>trunc .. to</tt>' Instruction</a></li>
189 <li><a href="#i_zext">'<tt>zext .. to</tt>' Instruction</a></li>
190 <li><a href="#i_sext">'<tt>sext .. to</tt>' Instruction</a></li>
191 <li><a href="#i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a></li>
192 <li><a href="#i_fpext">'<tt>fpext .. to</tt>' Instruction</a></li>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]193 <li><a href="#i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a></li>
194 <li><a href="#i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a></li>
195 <li><a href="#i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a></li>
196 <li><a href="#i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a></li>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]197 <li><a href="#i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a></li>
198 <li><a href="#i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a></li>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]199 <li><a href="#i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a></li>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]200 </ol>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]201 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]202 <li><a href="#otherops">Other Operations</a>
203 <ol>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]204 <li><a href="#i_icmp">'<tt>icmp</tt>' Instruction</a></li>
205 <li><a href="#i_fcmp">'<tt>fcmp</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]206 <li><a href="#i_phi">'<tt>phi</tt>' Instruction</a></li>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]207 <li><a href="#i_select">'<tt>select</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]208 <li><a href="#i_call">'<tt>call</tt>' Instruction</a></li>
Chris Lattner33337472006-01-13 23:26:01 +0000[diff] [blame]209 <li><a href="#i_va_arg">'<tt>va_arg</tt>' Instruction</a></li>
Bill Wendlingbbcb7cd2011-08-02 21:52:38 +0000[diff] [blame]210 <li><a href="#i_landingpad">'<tt>landingpad</tt>' Instruction</a></li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]211 </ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]212 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]213 </ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]214 </li>
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]215 <li><a href="#intrinsics">Intrinsic Functions</a>
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]216 <ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]217 <li><a href="#int_varargs">Variable Argument Handling Intrinsics</a>
218 <ol>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]219 <li><a href="#int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a></li>
220 <li><a href="#int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a></li>
221 <li><a href="#int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]222 </ol>
223 </li>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]224 <li><a href="#int_gc">Accurate Garbage Collection Intrinsics</a>
225 <ol>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]226 <li><a href="#int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a></li>
227 <li><a href="#int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a></li>
228 <li><a href="#int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a></li>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]229 </ol>
230 </li>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]231 <li><a href="#int_codegen">Code Generator Intrinsics</a>
232 <ol>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]233 <li><a href="#int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a></li>
234 <li><a href="#int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a></li>
235 <li><a href="#int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a></li>
236 <li><a href="#int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a></li>
237 <li><a href="#int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a></li>
238 <li><a href="#int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a></li>
Dan Gohmane58f7b32010-05-26 21:56:15 +0000[diff] [blame]239 <li><a href="#int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a></li>
John Criswellaa1c3c12004-04-09 16:43:20 +0000[diff] [blame]240 </ol>
241 </li>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]242 <li><a href="#int_libc">Standard C Library Intrinsics</a>
243 <ol>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]244 <li><a href="#int_memcpy">'<tt>llvm.memcpy.*</tt>' Intrinsic</a></li>
245 <li><a href="#int_memmove">'<tt>llvm.memmove.*</tt>' Intrinsic</a></li>
246 <li><a href="#int_memset">'<tt>llvm.memset.*</tt>' Intrinsic</a></li>
247 <li><a href="#int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a></li>
248 <li><a href="#int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a></li>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]249 <li><a href="#int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a></li>
250 <li><a href="#int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a></li>
251 <li><a href="#int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a></li>
Dan Gohmane635c522011-05-27 00:36:31 +0000[diff] [blame]252 <li><a href="#int_exp">'<tt>llvm.exp.*</tt>' Intrinsic</a></li>
253 <li><a href="#int_log">'<tt>llvm.log.*</tt>' Intrinsic</a></li>
Cameron Zwarichf03fa182011-07-08 21:39:21 +0000[diff] [blame]254 <li><a href="#int_fma">'<tt>llvm.fma.*</tt>' Intrinsic</a></li>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]255 </ol>
256 </li>
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]257 <li><a href="#int_manip">Bit Manipulation Intrinsics</a>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]258 <ol>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]259 <li><a href="#int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a></li>
Chris Lattnerb748c672006-01-16 22:34:14 +0000[diff] [blame]260 <li><a href="#int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic </a></li>
261 <li><a href="#int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic </a></li>
262 <li><a href="#int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic </a></li>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]263 </ol>
264 </li>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]265 <li><a href="#int_overflow">Arithmetic with Overflow Intrinsics</a>
266 <ol>
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]267 <li><a href="#int_sadd_overflow">'<tt>llvm.sadd.with.overflow.*</tt> Intrinsics</a></li>
268 <li><a href="#int_uadd_overflow">'<tt>llvm.uadd.with.overflow.*</tt> Intrinsics</a></li>
269 <li><a href="#int_ssub_overflow">'<tt>llvm.ssub.with.overflow.*</tt> Intrinsics</a></li>
270 <li><a href="#int_usub_overflow">'<tt>llvm.usub.with.overflow.*</tt> Intrinsics</a></li>
271 <li><a href="#int_smul_overflow">'<tt>llvm.smul.with.overflow.*</tt> Intrinsics</a></li>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]272 <li><a href="#int_umul_overflow">'<tt>llvm.umul.with.overflow.*</tt> Intrinsics</a></li>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]273 </ol>
274 </li>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]275 <li><a href="#int_fp16">Half Precision Floating Point Intrinsics</a>
276 <ol>
Chris Lattnerbbd8bd32010-03-14 23:03:31 +0000[diff] [blame]277 <li><a href="#int_convert_to_fp16">'<tt>llvm.convert.to.fp16</tt>' Intrinsic</a></li>
278 <li><a href="#int_convert_from_fp16">'<tt>llvm.convert.from.fp16</tt>' Intrinsic</a></li>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]279 </ol>
280 </li>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]281 <li><a href="#int_debugger">Debugger intrinsics</a></li>
Jim Laskey2211f492007-03-14 19:31:19 +0000[diff] [blame]282 <li><a href="#int_eh">Exception Handling intrinsics</a></li>
Duncan Sandsa0984362011-09-06 13:37:06 +0000[diff] [blame]283 <li><a href="#int_trampoline">Trampoline Intrinsics</a>
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]284 <ol>
285 <li><a href="#int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a></li>
Duncan Sandsa0984362011-09-06 13:37:06 +0000[diff] [blame]286 <li><a href="#int_at">'<tt>llvm.adjust.trampoline</tt>' Intrinsic</a></li>
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]287 </ol>
288 </li>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]289 <li><a href="#int_memorymarkers">Memory Use Markers</a>
290 <ol>
291 <li><a href="#int_lifetime_start"><tt>llvm.lifetime.start</tt></a></li>
292 <li><a href="#int_lifetime_end"><tt>llvm.lifetime.end</tt></a></li>
293 <li><a href="#int_invariant_start"><tt>llvm.invariant.start</tt></a></li>
294 <li><a href="#int_invariant_end"><tt>llvm.invariant.end</tt></a></li>
295 </ol>
296 </li>
Reid Spencer5b2cb0f2007-07-20 19:59:11 +0000[diff] [blame]297 <li><a href="#int_general">General intrinsics</a>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]298 <ol>
Reid Spencer5b2cb0f2007-07-20 19:59:11 +0000[diff] [blame]299 <li><a href="#int_var_annotation">
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]300 '<tt>llvm.var.annotation</tt>' Intrinsic</a></li>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]301 <li><a href="#int_annotation">
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]302 '<tt>llvm.annotation.*</tt>' Intrinsic</a></li>
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]303 <li><a href="#int_trap">
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]304 '<tt>llvm.trap</tt>' Intrinsic</a></li>
305 <li><a href="#int_stackprotector">
306 '<tt>llvm.stackprotector</tt>' Intrinsic</a></li>
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]307 <li><a href="#int_objectsize">
308 '<tt>llvm.objectsize</tt>' Intrinsic</a></li>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]309 </ol>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]310 </li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]311 </ol>
312 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]313</ol>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]314
315<div class="doc_author">
316 <p>Written by <a href="mailto:sabre@nondot.org">Chris Lattner</a>
317 and <a href="mailto:vadve@cs.uiuc.edu">Vikram Adve</a></p>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]318</div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]319
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]320<!-- *********************************************************************** -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]321<h2><a name="abstract">Abstract</a></h2>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]322<!-- *********************************************************************** -->
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]323
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]324<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]325
326<p>This document is a reference manual for the LLVM assembly language. LLVM is
327 a Static Single Assignment (SSA) based representation that provides type
328 safety, low-level operations, flexibility, and the capability of representing
329 'all' high-level languages cleanly. It is the common code representation
330 used throughout all phases of the LLVM compilation strategy.</p>
331
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]332</div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]333
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]334<!-- *********************************************************************** -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]335<h2><a name="introduction">Introduction</a></h2>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]336<!-- *********************************************************************** -->
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]337
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]338<div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]339
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]340<p>The LLVM code representation is designed to be used in three different forms:
341 as an in-memory compiler IR, as an on-disk bitcode representation (suitable
342 for fast loading by a Just-In-Time compiler), and as a human readable
343 assembly language representation. This allows LLVM to provide a powerful
344 intermediate representation for efficient compiler transformations and
345 analysis, while providing a natural means to debug and visualize the
346 transformations. The three different forms of LLVM are all equivalent. This
347 document describes the human readable representation and notation.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]348
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]349<p>The LLVM representation aims to be light-weight and low-level while being
350 expressive, typed, and extensible at the same time. It aims to be a
351 "universal IR" of sorts, by being at a low enough level that high-level ideas
352 may be cleanly mapped to it (similar to how microprocessors are "universal
353 IR's", allowing many source languages to be mapped to them). By providing
354 type information, LLVM can be used as the target of optimizations: for
355 example, through pointer analysis, it can be proven that a C automatic
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]356 variable is never accessed outside of the current function, allowing it to
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]357 be promoted to a simple SSA value instead of a memory location.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]358
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]359<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]360<h4>
361 <a name="wellformed">Well-Formedness</a>
362</h4>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]363
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]364<div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]365
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]366<p>It is important to note that this document describes 'well formed' LLVM
367 assembly language. There is a difference between what the parser accepts and
368 what is considered 'well formed'. For example, the following instruction is
369 syntactically okay, but not well formed:</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]370
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]371<pre class="doc_code">
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]372%x = <a href="#i_add">add</a> i32 1, %x
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]373</pre>
374
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]375<p>because the definition of <tt>%x</tt> does not dominate all of its uses. The
376 LLVM infrastructure provides a verification pass that may be used to verify
377 that an LLVM module is well formed. This pass is automatically run by the
378 parser after parsing input assembly and by the optimizer before it outputs
379 bitcode. The violations pointed out by the verifier pass indicate bugs in
380 transformation passes or input to the parser.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]381
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]382</div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]383
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]384</div>
385
Chris Lattner87a3dbe2007-10-03 17:34:29 +0000[diff] [blame]386<!-- Describe the typesetting conventions here. -->
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]387
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]388<!-- *********************************************************************** -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]389<h2><a name="identifiers">Identifiers</a></h2>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]390<!-- *********************************************************************** -->
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]391
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]392<div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]393
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]394<p>LLVM identifiers come in two basic types: global and local. Global
395 identifiers (functions, global variables) begin with the <tt>'@'</tt>
396 character. Local identifiers (register names, types) begin with
397 the <tt>'%'</tt> character. Additionally, there are three different formats
398 for identifiers, for different purposes:</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]399
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]400<ol>
Reid Spencerb23b65f2007-08-07 14:34:28 +0000[diff] [blame]401 <li>Named values are represented as a string of characters with their prefix.
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]402 For example, <tt>%foo</tt>, <tt>@DivisionByZero</tt>,
403 <tt>%a.really.long.identifier</tt>. The actual regular expression used is
404 '<tt>[%@][a-zA-Z$._][a-zA-Z$._0-9]*</tt>'. Identifiers which require
405 other characters in their names can be surrounded with quotes. Special
406 characters may be escaped using <tt>"\xx"</tt> where <tt>xx</tt> is the
407 ASCII code for the character in hexadecimal. In this way, any character
408 can be used in a name value, even quotes themselves.</li>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]409
Reid Spencerb23b65f2007-08-07 14:34:28 +0000[diff] [blame]410 <li>Unnamed values are represented as an unsigned numeric value with their
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]411 prefix. For example, <tt>%12</tt>, <tt>@2</tt>, <tt>%44</tt>.</li>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]412
Reid Spencer8f08d802004-12-09 18:02:53 +0000[diff] [blame]413 <li>Constants, which are described in a <a href="#constants">section about
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]414 constants</a>, below.</li>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]415</ol>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]416
Reid Spencerb23b65f2007-08-07 14:34:28 +0000[diff] [blame]417<p>LLVM requires that values start with a prefix for two reasons: Compilers
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]418 don't need to worry about name clashes with reserved words, and the set of
419 reserved words may be expanded in the future without penalty. Additionally,
420 unnamed identifiers allow a compiler to quickly come up with a temporary
421 variable without having to avoid symbol table conflicts.</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]422
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]423<p>Reserved words in LLVM are very similar to reserved words in other
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]424 languages. There are keywords for different opcodes
425 ('<tt><a href="#i_add">add</a></tt>',
426 '<tt><a href="#i_bitcast">bitcast</a></tt>',
427 '<tt><a href="#i_ret">ret</a></tt>', etc...), for primitive type names
428 ('<tt><a href="#t_void">void</a></tt>',
429 '<tt><a href="#t_primitive">i32</a></tt>', etc...), and others. These
430 reserved words cannot conflict with variable names, because none of them
431 start with a prefix character (<tt>'%'</tt> or <tt>'@'</tt>).</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]432
433<p>Here is an example of LLVM code to multiply the integer variable
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]434 '<tt>%X</tt>' by 8:</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]435
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]436<p>The easy way:</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]437
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]438<pre class="doc_code">
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]439%result = <a href="#i_mul">mul</a> i32 %X, 8
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]440</pre>
441
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]442<p>After strength reduction:</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]443
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]444<pre class="doc_code">
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]445%result = <a href="#i_shl">shl</a> i32 %X, i8 3
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]446</pre>
447
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]448<p>And the hard way:</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]449
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]450<pre class="doc_code">
Gabor Greifbd0328f2009-10-28 13:05:07 +0000[diff] [blame]451%0 = <a href="#i_add">add</a> i32 %X, %X <i>; yields {i32}:%0</i>
452%1 = <a href="#i_add">add</a> i32 %0, %0 <i>; yields {i32}:%1</i>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]453%result = <a href="#i_add">add</a> i32 %1, %1
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]454</pre>
455
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]456<p>This last way of multiplying <tt>%X</tt> by 8 illustrates several important
457 lexical features of LLVM:</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]458
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]459<ol>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]460 <li>Comments are delimited with a '<tt>;</tt>' and go until the end of
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]461 line.</li>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]462
463 <li>Unnamed temporaries are created when the result of a computation is not
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]464 assigned to a named value.</li>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]465
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]466 <li>Unnamed temporaries are numbered sequentially</li>
467</ol>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]468
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]469<p>It also shows a convention that we follow in this document. When
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]470 demonstrating instructions, we will follow an instruction with a comment that
471 defines the type and name of value produced. Comments are shown in italic
472 text.</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]473
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]474</div>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]475
476<!-- *********************************************************************** -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]477<h2><a name="highlevel">High Level Structure</a></h2>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]478<!-- *********************************************************************** -->
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]479<div>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]480<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]481<h3>
482 <a name="modulestructure">Module Structure</a>
483</h3>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]484
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]485<div>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]486
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]487<p>LLVM programs are composed of "Module"s, each of which is a translation unit
488 of the input programs. Each module consists of functions, global variables,
489 and symbol table entries. Modules may be combined together with the LLVM
490 linker, which merges function (and global variable) definitions, resolves
491 forward declarations, and merges symbol table entries. Here is an example of
492 the "hello world" module:</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]493
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]494<pre class="doc_code">
Chris Lattner54a7be72010-08-17 17:13:42 +0000[diff] [blame]495<i>; Declare the string constant as a global constant.</i>&nbsp;
Nick Lewyckyfea7ddc2011-01-29 01:09:53 +0000[diff] [blame]496<a href="#identifiers">@.LC0</a> = <a href="#linkage_internal">internal</a>&nbsp;<a href="#globalvars">constant</a>&nbsp;<a href="#t_array">[13 x i8]</a> c"hello world\0A\00" <i>; [13 x i8]*</i>&nbsp;
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]497
Chris Lattner54a7be72010-08-17 17:13:42 +0000[diff] [blame]498<i>; External declaration of the puts function</i>&nbsp;
499<a href="#functionstructure">declare</a> i32 @puts(i8*) <i>; i32 (i8*)* </i>&nbsp;
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]500
501<i>; Definition of main function</i>
Chris Lattner54a7be72010-08-17 17:13:42 +0000[diff] [blame]502define i32 @main() { <i>; i32()* </i>&nbsp;
503 <i>; Convert [13 x i8]* to i8 *...</i>&nbsp;
504 %cast210 = <a href="#i_getelementptr">getelementptr</a> [13 x i8]* @.LC0, i64 0, i64 0 <i>; i8*</i>&nbsp;
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]505
Chris Lattner54a7be72010-08-17 17:13:42 +0000[diff] [blame]506 <i>; Call puts function to write out the string to stdout.</i>&nbsp;
507 <a href="#i_call">call</a> i32 @puts(i8* %cast210) <i>; i32</i>&nbsp;
508 <a href="#i_ret">ret</a> i32 0&nbsp;
509}
Devang Pateld1a89692010-01-11 19:35:55 +0000[diff] [blame]510
511<i>; Named metadata</i>
512!1 = metadata !{i32 41}
513!foo = !{!1, null}
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]514</pre>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]515
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]516<p>This example is made up of a <a href="#globalvars">global variable</a> named
Devang Pateld1a89692010-01-11 19:35:55 +0000[diff] [blame]517 "<tt>.LC0</tt>", an external declaration of the "<tt>puts</tt>" function,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]518 a <a href="#functionstructure">function definition</a> for
Devang Pateld1a89692010-01-11 19:35:55 +0000[diff] [blame]519 "<tt>main</tt>" and <a href="#namedmetadatastructure">named metadata</a>
520 "<tt>foo"</tt>.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]521
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]522<p>In general, a module is made up of a list of global values, where both
523 functions and global variables are global values. Global values are
524 represented by a pointer to a memory location (in this case, a pointer to an
525 array of char, and a pointer to a function), and have one of the
526 following <a href="#linkage">linkage types</a>.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]527
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]528</div>
529
530<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]531<h3>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]532 <a name="linkage">Linkage Types</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]533</h3>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]534
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]535<div>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]536
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]537<p>All Global Variables and Functions have one of the following types of
538 linkage:</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]539
540<dl>
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]541 <dt><tt><b><a name="linkage_private">private</a></b></tt></dt>
Bill Wendling03bcd6e2010-07-01 21:55:59 +0000[diff] [blame]542 <dd>Global values with "<tt>private</tt>" linkage are only directly accessible
543 by objects in the current module. In particular, linking code into a
544 module with an private global value may cause the private to be renamed as
545 necessary to avoid collisions. Because the symbol is private to the
546 module, all references can be updated. This doesn't show up in any symbol
547 table in the object file.</dd>
Rafael Espindola6de96a12009-01-15 20:18:42 +0000[diff] [blame]548
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]549 <dt><tt><b><a name="linkage_linker_private">linker_private</a></b></tt></dt>
Bill Wendling03bcd6e2010-07-01 21:55:59 +0000[diff] [blame]550 <dd>Similar to <tt>private</tt>, but the symbol is passed through the
551 assembler and evaluated by the linker. Unlike normal strong symbols, they
552 are removed by the linker from the final linked image (executable or
553 dynamic library).</dd>
554
555 <dt><tt><b><a name="linkage_linker_private_weak">linker_private_weak</a></b></tt></dt>
556 <dd>Similar to "<tt>linker_private</tt>", but the symbol is weak. Note that
557 <tt>linker_private_weak</tt> symbols are subject to coalescing by the
558 linker. The symbols are removed by the linker from the final linked image
559 (executable or dynamic library).</dd>
Bill Wendlinga3c6f6b2009-07-20 01:03:30 +0000[diff] [blame]560
Bill Wendling578ee402010-08-20 22:05:50 +0000[diff] [blame]561 <dt><tt><b><a name="linkage_linker_private_weak_def_auto">linker_private_weak_def_auto</a></b></tt></dt>
562 <dd>Similar to "<tt>linker_private_weak</tt>", but it's known that the address
563 of the object is not taken. For instance, functions that had an inline
564 definition, but the compiler decided not to inline it. Note,
565 unlike <tt>linker_private</tt> and <tt>linker_private_weak</tt>,
566 <tt>linker_private_weak_def_auto</tt> may have only <tt>default</tt>
567 visibility. The symbols are removed by the linker from the final linked
568 image (executable or dynamic library).</dd>
569
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]570 <dt><tt><b><a name="linkage_internal">internal</a></b></tt></dt>
Bill Wendling36321712010-06-29 22:34:52 +0000[diff] [blame]571 <dd>Similar to private, but the value shows as a local symbol
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]572 (<tt>STB_LOCAL</tt> in the case of ELF) in the object file. This
573 corresponds to the notion of the '<tt>static</tt>' keyword in C.</dd>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]574
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]575 <dt><tt><b><a name="linkage_available_externally">available_externally</a></b></tt></dt>
Chris Lattner184f1be2009-04-13 05:44:34 +0000[diff] [blame]576 <dd>Globals with "<tt>available_externally</tt>" linkage are never emitted
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]577 into the object file corresponding to the LLVM module. They exist to
578 allow inlining and other optimizations to take place given knowledge of
579 the definition of the global, which is known to be somewhere outside the
580 module. Globals with <tt>available_externally</tt> linkage are allowed to
581 be discarded at will, and are otherwise the same as <tt>linkonce_odr</tt>.
582 This linkage type is only allowed on definitions, not declarations.</dd>
Chris Lattner184f1be2009-04-13 05:44:34 +0000[diff] [blame]583
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]584 <dt><tt><b><a name="linkage_linkonce">linkonce</a></b></tt></dt>
Chris Lattnere20b4702007-01-14 06:51:48 +0000[diff] [blame]585 <dd>Globals with "<tt>linkonce</tt>" linkage are merged with other globals of
Chris Lattner0de4caa2010-01-09 19:15:14 +0000[diff] [blame]586 the same name when linkage occurs. This can be used to implement
587 some forms of inline functions, templates, or other code which must be
588 generated in each translation unit that uses it, but where the body may
589 be overridden with a more definitive definition later. Unreferenced
590 <tt>linkonce</tt> globals are allowed to be discarded. Note that
591 <tt>linkonce</tt> linkage does not actually allow the optimizer to
592 inline the body of this function into callers because it doesn't know if
593 this definition of the function is the definitive definition within the
594 program or whether it will be overridden by a stronger definition.
595 To enable inlining and other optimizations, use "<tt>linkonce_odr</tt>"
596 linkage.</dd>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]597
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]598 <dt><tt><b><a name="linkage_weak">weak</a></b></tt></dt>
Chris Lattnerd0554882009-08-05 05:21:07 +0000[diff] [blame]599 <dd>"<tt>weak</tt>" linkage has the same merging semantics as
600 <tt>linkonce</tt> linkage, except that unreferenced globals with
601 <tt>weak</tt> linkage may not be discarded. This is used for globals that
602 are declared "weak" in C source code.</dd>
603
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]604 <dt><tt><b><a name="linkage_common">common</a></b></tt></dt>
Chris Lattnerd0554882009-08-05 05:21:07 +0000[diff] [blame]605 <dd>"<tt>common</tt>" linkage is most similar to "<tt>weak</tt>" linkage, but
606 they are used for tentative definitions in C, such as "<tt>int X;</tt>" at
607 global scope.
608 Symbols with "<tt>common</tt>" linkage are merged in the same way as
609 <tt>weak symbols</tt>, and they may not be deleted if unreferenced.
Chris Lattner0aff0b22009-08-05 05:41:44 +0000[diff] [blame]610 <tt>common</tt> symbols may not have an explicit section,
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]611 must have a zero initializer, and may not be marked '<a
Chris Lattner0aff0b22009-08-05 05:41:44 +0000[diff] [blame]612 href="#globalvars"><tt>constant</tt></a>'. Functions and aliases may not
613 have common linkage.</dd>
Chris Lattnerd0554882009-08-05 05:21:07 +0000[diff] [blame]614
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]615
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]616 <dt><tt><b><a name="linkage_appending">appending</a></b></tt></dt>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]617 <dd>"<tt>appending</tt>" linkage may only be applied to global variables of
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]618 pointer to array type. When two global variables with appending linkage
619 are linked together, the two global arrays are appended together. This is
620 the LLVM, typesafe, equivalent of having the system linker append together
621 "sections" with identical names when .o files are linked.</dd>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]622
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]623 <dt><tt><b><a name="linkage_externweak">extern_weak</a></b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]624 <dd>The semantics of this linkage follow the ELF object file model: the symbol
625 is weak until linked, if not linked, the symbol becomes null instead of
626 being an undefined reference.</dd>
Anton Korobeynikova0554d92007-01-12 19:20:47 +0000[diff] [blame]627
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]628 <dt><tt><b><a name="linkage_linkonce_odr">linkonce_odr</a></b></tt></dt>
629 <dt><tt><b><a name="linkage_weak_odr">weak_odr</a></b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]630 <dd>Some languages allow differing globals to be merged, such as two functions
631 with different semantics. Other languages, such as <tt>C++</tt>, ensure
Bill Wendling03bcd6e2010-07-01 21:55:59 +0000[diff] [blame]632 that only equivalent globals are ever merged (the "one definition rule"
633 &mdash; "ODR"). Such languages can use the <tt>linkonce_odr</tt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]634 and <tt>weak_odr</tt> linkage types to indicate that the global will only
635 be merged with equivalent globals. These linkage types are otherwise the
636 same as their non-<tt>odr</tt> versions.</dd>
Duncan Sands12da8ce2009-03-07 15:45:40 +0000[diff] [blame]637
Bill Wendlingef3cdea2011-11-04 20:40:41 +0000[diff] [blame]638 <dt><tt><b><a name="linkage_external">external</a></b></tt></dt>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]639 <dd>If none of the above identifiers are used, the global is externally
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]640 visible, meaning that it participates in linkage and can be used to
641 resolve external symbol references.</dd>
Reid Spencer7972c472007-04-11 23:49:50 +0000[diff] [blame]642</dl>
Anton Korobeynikovd61d39e2006-09-14 18:23:27 +0000[diff] [blame]643
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]644<p>The next two types of linkage are targeted for Microsoft Windows platform
645 only. They are designed to support importing (exporting) symbols from (to)
646 DLLs (Dynamic Link Libraries).</p>
Anton Korobeynikovd61d39e2006-09-14 18:23:27 +0000[diff] [blame]647
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]648<dl>
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]649 <dt><tt><b><a name="linkage_dllimport">dllimport</a></b></tt></dt>
Anton Korobeynikovd61d39e2006-09-14 18:23:27 +0000[diff] [blame]650 <dd>"<tt>dllimport</tt>" linkage causes the compiler to reference a function
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]651 or variable via a global pointer to a pointer that is set up by the DLL
652 exporting the symbol. On Microsoft Windows targets, the pointer name is
653 formed by combining <code>__imp_</code> and the function or variable
654 name.</dd>
Anton Korobeynikovd61d39e2006-09-14 18:23:27 +0000[diff] [blame]655
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]656 <dt><tt><b><a name="linkage_dllexport">dllexport</a></b></tt></dt>
Anton Korobeynikovd61d39e2006-09-14 18:23:27 +0000[diff] [blame]657 <dd>"<tt>dllexport</tt>" linkage causes the compiler to provide a global
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]658 pointer to a pointer in a DLL, so that it can be referenced with the
659 <tt>dllimport</tt> attribute. On Microsoft Windows targets, the pointer
660 name is formed by combining <code>__imp_</code> and the function or
661 variable name.</dd>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]662</dl>
663
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]664<p>For example, since the "<tt>.LC0</tt>" variable is defined to be internal, if
665 another module defined a "<tt>.LC0</tt>" variable and was linked with this
666 one, one of the two would be renamed, preventing a collision. Since
667 "<tt>main</tt>" and "<tt>puts</tt>" are external (i.e., lacking any linkage
668 declarations), they are accessible outside of the current module.</p>
669
670<p>It is illegal for a function <i>declaration</i> to have any linkage type
Bill Wendlingb4d076e2011-10-11 06:41:28 +0000[diff] [blame]671 other than <tt>external</tt>, <tt>dllimport</tt>
672 or <tt>extern_weak</tt>.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]673
Duncan Sands12da8ce2009-03-07 15:45:40 +0000[diff] [blame]674<p>Aliases can have only <tt>external</tt>, <tt>internal</tt>, <tt>weak</tt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]675 or <tt>weak_odr</tt> linkages.</p>
676
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]677</div>
678
679<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]680<h3>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]681 <a name="callingconv">Calling Conventions</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]682</h3>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]683
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]684<div>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]685
686<p>LLVM <a href="#functionstructure">functions</a>, <a href="#i_call">calls</a>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]687 and <a href="#i_invoke">invokes</a> can all have an optional calling
688 convention specified for the call. The calling convention of any pair of
689 dynamic caller/callee must match, or the behavior of the program is
690 undefined. The following calling conventions are supported by LLVM, and more
691 may be added in the future:</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]692
693<dl>
694 <dt><b>"<tt>ccc</tt>" - The C calling convention</b>:</dt>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]695 <dd>This calling convention (the default if no other calling convention is
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]696 specified) matches the target C calling conventions. This calling
697 convention supports varargs function calls and tolerates some mismatch in
698 the declared prototype and implemented declaration of the function (as
699 does normal C).</dd>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]700
701 <dt><b>"<tt>fastcc</tt>" - The fast calling convention</b>:</dt>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]702 <dd>This calling convention attempts to make calls as fast as possible
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]703 (e.g. by passing things in registers). This calling convention allows the
704 target to use whatever tricks it wants to produce fast code for the
705 target, without having to conform to an externally specified ABI
Jeffrey Yasskinb8677462010-01-09 19:44:16 +0000[diff] [blame]706 (Application Binary Interface).
707 <a href="CodeGenerator.html#tailcallopt">Tail calls can only be optimized
Chris Lattnera179e4d2010-03-11 00:22:57 +0000[diff] [blame]708 when this or the GHC convention is used.</a> This calling convention
709 does not support varargs and requires the prototype of all callees to
710 exactly match the prototype of the function definition.</dd>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]711
712 <dt><b>"<tt>coldcc</tt>" - The cold calling convention</b>:</dt>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]713 <dd>This calling convention attempts to make code in the caller as efficient
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]714 as possible under the assumption that the call is not commonly executed.
715 As such, these calls often preserve all registers so that the call does
716 not break any live ranges in the caller side. This calling convention
717 does not support varargs and requires the prototype of all callees to
718 exactly match the prototype of the function definition.</dd>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]719
Chris Lattnera179e4d2010-03-11 00:22:57 +0000[diff] [blame]720 <dt><b>"<tt>cc <em>10</em></tt>" - GHC convention</b>:</dt>
721 <dd>This calling convention has been implemented specifically for use by the
722 <a href="http://www.haskell.org/ghc">Glasgow Haskell Compiler (GHC)</a>.
723 It passes everything in registers, going to extremes to achieve this by
724 disabling callee save registers. This calling convention should not be
725 used lightly but only for specific situations such as an alternative to
726 the <em>register pinning</em> performance technique often used when
727 implementing functional programming languages.At the moment only X86
728 supports this convention and it has the following limitations:
729 <ul>
730 <li>On <em>X86-32</em> only supports up to 4 bit type parameters. No
731 floating point types are supported.</li>
732 <li>On <em>X86-64</em> only supports up to 10 bit type parameters and
733 6 floating point parameters.</li>
734 </ul>
735 This calling convention supports
736 <a href="CodeGenerator.html#tailcallopt">tail call optimization</a> but
737 requires both the caller and callee are using it.
738 </dd>
739
Chris Lattner573f64e2005-05-07 01:46:40 +0000[diff] [blame]740 <dt><b>"<tt>cc &lt;<em>n</em>&gt;</tt>" - Numbered convention</b>:</dt>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]741 <dd>Any calling convention may be specified by number, allowing
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]742 target-specific calling conventions to be used. Target specific calling
743 conventions start at 64.</dd>
Chris Lattner573f64e2005-05-07 01:46:40 +0000[diff] [blame]744</dl>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]745
746<p>More calling conventions can be added/defined on an as-needed basis, to
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]747 support Pascal conventions or any other well-known target-independent
748 convention.</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]749
750</div>
751
752<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]753<h3>
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]754 <a name="visibility">Visibility Styles</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]755</h3>
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]756
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]757<div>
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]758
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]759<p>All Global Variables and Functions have one of the following visibility
760 styles:</p>
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]761
762<dl>
763 <dt><b>"<tt>default</tt>" - Default style</b>:</dt>
Chris Lattner67c37d12008-08-05 18:29:16 +0000[diff] [blame]764 <dd>On targets that use the ELF object file format, default visibility means
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]765 that the declaration is visible to other modules and, in shared libraries,
766 means that the declared entity may be overridden. On Darwin, default
767 visibility means that the declaration is visible to other modules. Default
768 visibility corresponds to "external linkage" in the language.</dd>
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]769
770 <dt><b>"<tt>hidden</tt>" - Hidden style</b>:</dt>
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]771 <dd>Two declarations of an object with hidden visibility refer to the same
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]772 object if they are in the same shared object. Usually, hidden visibility
773 indicates that the symbol will not be placed into the dynamic symbol
774 table, so no other module (executable or shared library) can reference it
775 directly.</dd>
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]776
Anton Korobeynikov39f3cff2007-04-29 18:35:00 +0000[diff] [blame]777 <dt><b>"<tt>protected</tt>" - Protected style</b>:</dt>
Anton Korobeynikov39f3cff2007-04-29 18:35:00 +0000[diff] [blame]778 <dd>On ELF, protected visibility indicates that the symbol will be placed in
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]779 the dynamic symbol table, but that references within the defining module
780 will bind to the local symbol. That is, the symbol cannot be overridden by
781 another module.</dd>
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]782</dl>
783
784</div>
785
786<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]787<h3>
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]788 <a name="namedtypes">Named Types</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]789</h3>
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]790
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]791<div>
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]792
793<p>LLVM IR allows you to specify name aliases for certain types. This can make
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]794 it easier to read the IR and make the IR more condensed (particularly when
795 recursive types are involved). An example of a name specification is:</p>
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]796
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]797<pre class="doc_code">
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]798%mytype = type { %mytype*, i32 }
799</pre>
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]800
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]801<p>You may give a name to any <a href="#typesystem">type</a> except
Chris Lattner249b9762010-08-17 23:26:04 +0000[diff] [blame]802 "<a href="#t_void">void</a>". Type name aliases may be used anywhere a type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]803 is expected with the syntax "%mytype".</p>
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]804
805<p>Note that type names are aliases for the structural type that they indicate,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]806 and that you can therefore specify multiple names for the same type. This
807 often leads to confusing behavior when dumping out a .ll file. Since LLVM IR
808 uses structural typing, the name is not part of the type. When printing out
809 LLVM IR, the printer will pick <em>one name</em> to render all types of a
810 particular shape. This means that if you have code where two different
811 source types end up having the same LLVM type, that the dumper will sometimes
812 print the "wrong" or unexpected type. This is an important design point and
813 isn't going to change.</p>
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]814
815</div>
816
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]817<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]818<h3>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]819 <a name="globalvars">Global Variables</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]820</h3>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]821
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]822<div>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]823
Chris Lattner5d5aede2005-02-12 19:30:21 +0000[diff] [blame]824<p>Global variables define regions of memory allocated at compilation time
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]825 instead of run-time. Global variables may optionally be initialized, may
826 have an explicit section to be placed in, and may have an optional explicit
827 alignment specified. A variable may be defined as "thread_local", which
828 means that it will not be shared by threads (each thread will have a
829 separated copy of the variable). A variable may be defined as a global
830 "constant," which indicates that the contents of the variable
831 will <b>never</b> be modified (enabling better optimization, allowing the
832 global data to be placed in the read-only section of an executable, etc).
833 Note that variables that need runtime initialization cannot be marked
834 "constant" as there is a store to the variable.</p>
Chris Lattner5d5aede2005-02-12 19:30:21 +0000[diff] [blame]835
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]836<p>LLVM explicitly allows <em>declarations</em> of global variables to be marked
837 constant, even if the final definition of the global is not. This capability
838 can be used to enable slightly better optimization of the program, but
839 requires the language definition to guarantee that optimizations based on the
840 'constantness' are valid for the translation units that do not include the
841 definition.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]842
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]843<p>As SSA values, global variables define pointer values that are in scope
844 (i.e. they dominate) all basic blocks in the program. Global variables
845 always define a pointer to their "content" type because they describe a
846 region of memory, and all memory objects in LLVM are accessed through
847 pointers.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]848
Rafael Espindola45e6c192011-01-08 16:42:36 +0000[diff] [blame]849<p>Global variables can be marked with <tt>unnamed_addr</tt> which indicates
850 that the address is not significant, only the content. Constants marked
Rafael Espindolaf1ed7812011-01-15 08:20:57 +0000[diff] [blame]851 like this can be merged with other constants if they have the same
852 initializer. Note that a constant with significant address <em>can</em>
853 be merged with a <tt>unnamed_addr</tt> constant, the result being a
854 constant whose address is significant.</p>
Rafael Espindola45e6c192011-01-08 16:42:36 +0000[diff] [blame]855
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]856<p>A global variable may be declared to reside in a target-specific numbered
857 address space. For targets that support them, address spaces may affect how
858 optimizations are performed and/or what target instructions are used to
859 access the variable. The default address space is zero. The address space
860 qualifier must precede any other attributes.</p>
Christopher Lamb308121c2007-12-11 09:31:00 +0000[diff] [blame]861
Chris Lattner662c8722005-11-12 00:45:07 +0000[diff] [blame]862<p>LLVM allows an explicit section to be specified for globals. If the target
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]863 supports it, it will emit globals to the section specified.</p>
Chris Lattner662c8722005-11-12 00:45:07 +0000[diff] [blame]864
Chris Lattner78e00bc2010-04-28 00:13:42 +0000[diff] [blame]865<p>An explicit alignment may be specified for a global, which must be a power
866 of 2. If not present, or if the alignment is set to zero, the alignment of
867 the global is set by the target to whatever it feels convenient. If an
868 explicit alignment is specified, the global is forced to have exactly that
Chris Lattner4bd85e42010-04-28 00:31:12 +0000[diff] [blame]869 alignment. Targets and optimizers are not allowed to over-align the global
870 if the global has an assigned section. In this case, the extra alignment
871 could be observable: for example, code could assume that the globals are
872 densely packed in their section and try to iterate over them as an array,
873 alignment padding would break this iteration.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]874
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]875<p>For example, the following defines a global in a numbered address space with
876 an initializer, section, and alignment:</p>
Chris Lattner5760c502007-01-14 00:27:09 +0000[diff] [blame]877
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]878<pre class="doc_code">
Dan Gohmanaaa679b2009-01-11 00:40:00 +0000[diff] [blame]879@G = addrspace(5) constant float 1.0, section "foo", align 4
Chris Lattner5760c502007-01-14 00:27:09 +0000[diff] [blame]880</pre>
881
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]882</div>
883
884
885<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]886<h3>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]887 <a name="functionstructure">Functions</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]888</h3>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]889
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]890<div>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]891
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]892<p>LLVM function definitions consist of the "<tt>define</tt>" keyword, an
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]893 optional <a href="#linkage">linkage type</a>, an optional
894 <a href="#visibility">visibility style</a>, an optional
Rafael Espindola45e6c192011-01-08 16:42:36 +0000[diff] [blame]895 <a href="#callingconv">calling convention</a>,
896 an optional <tt>unnamed_addr</tt> attribute, a return type, an optional
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]897 <a href="#paramattrs">parameter attribute</a> for the return type, a function
898 name, a (possibly empty) argument list (each with optional
899 <a href="#paramattrs">parameter attributes</a>), optional
900 <a href="#fnattrs">function attributes</a>, an optional section, an optional
901 alignment, an optional <a href="#gc">garbage collector name</a>, an opening
902 curly brace, a list of basic blocks, and a closing curly brace.</p>
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]903
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]904<p>LLVM function declarations consist of the "<tt>declare</tt>" keyword, an
905 optional <a href="#linkage">linkage type</a>, an optional
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]906 <a href="#visibility">visibility style</a>, an optional
Rafael Espindola45e6c192011-01-08 16:42:36 +0000[diff] [blame]907 <a href="#callingconv">calling convention</a>,
908 an optional <tt>unnamed_addr</tt> attribute, a return type, an optional
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]909 <a href="#paramattrs">parameter attribute</a> for the return type, a function
910 name, a possibly empty list of arguments, an optional alignment, and an
911 optional <a href="#gc">garbage collector name</a>.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]912
Chris Lattner67c37d12008-08-05 18:29:16 +0000[diff] [blame]913<p>A function definition contains a list of basic blocks, forming the CFG
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]914 (Control Flow Graph) for the function. Each basic block may optionally start
915 with a label (giving the basic block a symbol table entry), contains a list
916 of instructions, and ends with a <a href="#terminators">terminator</a>
917 instruction (such as a branch or function return).</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]918
Chris Lattnera59fb102007-06-08 16:52:14 +0000[diff] [blame]919<p>The first basic block in a function is special in two ways: it is immediately
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]920 executed on entrance to the function, and it is not allowed to have
921 predecessor basic blocks (i.e. there can not be any branches to the entry
922 block of a function). Because the block can have no predecessors, it also
923 cannot have any <a href="#i_phi">PHI nodes</a>.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]924
Chris Lattner662c8722005-11-12 00:45:07 +0000[diff] [blame]925<p>LLVM allows an explicit section to be specified for functions. If the target
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]926 supports it, it will emit functions to the section specified.</p>
Chris Lattner662c8722005-11-12 00:45:07 +0000[diff] [blame]927
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]928<p>An explicit alignment may be specified for a function. If not present, or if
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]929 the alignment is set to zero, the alignment of the function is set by the
930 target to whatever it feels convenient. If an explicit alignment is
931 specified, the function is forced to have at least that much alignment. All
932 alignments must be a power of 2.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]933
Rafael Espindola45e6c192011-01-08 16:42:36 +0000[diff] [blame]934<p>If the <tt>unnamed_addr</tt> attribute is given, the address is know to not
Bill Wendlingef3cdea2011-11-04 20:40:41 +0000[diff] [blame]935 be significant and two identical functions can be merged.</p>
Rafael Espindola45e6c192011-01-08 16:42:36 +0000[diff] [blame]936
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]937<h5>Syntax:</h5>
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]938<pre class="doc_code">
Chris Lattner0ae02092008-10-13 16:55:18 +0000[diff] [blame]939define [<a href="#linkage">linkage</a>] [<a href="#visibility">visibility</a>]
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]940 [<a href="#callingconv">cconv</a>] [<a href="#paramattrs">ret attrs</a>]
941 &lt;ResultType&gt; @&lt;FunctionName&gt; ([argument list])
942 [<a href="#fnattrs">fn Attrs</a>] [section "name"] [align N]
943 [<a href="#gc">gc</a>] { ... }
944</pre>
Devang Patel02256232008-10-07 17:48:33 +0000[diff] [blame]945
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]946</div>
947
Anton Korobeynikova97b6942007-04-25 14:27:10 +0000[diff] [blame]948<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]949<h3>
Anton Korobeynikova97b6942007-04-25 14:27:10 +0000[diff] [blame]950 <a name="aliasstructure">Aliases</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]951</h3>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]952
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]953<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]954
955<p>Aliases act as "second name" for the aliasee value (which can be either
956 function, global variable, another alias or bitcast of global value). Aliases
957 may have an optional <a href="#linkage">linkage type</a>, and an
958 optional <a href="#visibility">visibility style</a>.</p>
Anton Korobeynikova97b6942007-04-25 14:27:10 +0000[diff] [blame]959
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]960<h5>Syntax:</h5>
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]961<pre class="doc_code">
Duncan Sands7e99a942008-09-12 20:48:21 +0000[diff] [blame]962@&lt;Name&gt; = alias [Linkage] [Visibility] &lt;AliaseeTy&gt; @&lt;Aliasee&gt;
Bill Wendling2d8b9a82007-05-29 09:42:13 +0000[diff] [blame]963</pre>
Anton Korobeynikova97b6942007-04-25 14:27:10 +0000[diff] [blame]964
965</div>
966
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]967<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]968<h3>
Devang Pateld1a89692010-01-11 19:35:55 +0000[diff] [blame]969 <a name="namedmetadatastructure">Named Metadata</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]970</h3>
Devang Pateld1a89692010-01-11 19:35:55 +0000[diff] [blame]971
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]972<div>
Devang Pateld1a89692010-01-11 19:35:55 +0000[diff] [blame]973
Chris Lattnerc2f8f162010-01-15 21:50:19 +0000[diff] [blame]974<p>Named metadata is a collection of metadata. <a href="#metadata">Metadata
Dan Gohman093cb792010-07-21 18:54:18 +0000[diff] [blame]975 nodes</a> (but not metadata strings) are the only valid operands for
Chris Lattnerc2f8f162010-01-15 21:50:19 +0000[diff] [blame]976 a named metadata.</p>
Devang Pateld1a89692010-01-11 19:35:55 +0000[diff] [blame]977
978<h5>Syntax:</h5>
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]979<pre class="doc_code">
Dan Gohman093cb792010-07-21 18:54:18 +0000[diff] [blame]980; Some unnamed metadata nodes, which are referenced by the named metadata.
981!0 = metadata !{metadata !"zero"}
Devang Pateld1a89692010-01-11 19:35:55 +0000[diff] [blame]982!1 = metadata !{metadata !"one"}
Dan Gohman093cb792010-07-21 18:54:18 +0000[diff] [blame]983!2 = metadata !{metadata !"two"}
Dan Gohman58cd65f2010-07-13 19:48:13 +0000[diff] [blame]984; A named metadata.
Dan Gohman093cb792010-07-21 18:54:18 +0000[diff] [blame]985!name = !{!0, !1, !2}
Devang Pateld1a89692010-01-11 19:35:55 +0000[diff] [blame]986</pre>
Devang Pateld1a89692010-01-11 19:35:55 +0000[diff] [blame]987
988</div>
989
990<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]991<h3>
992 <a name="paramattrs">Parameter Attributes</a>
993</h3>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]994
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]995<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]996
997<p>The return type and each parameter of a function type may have a set of
998 <i>parameter attributes</i> associated with them. Parameter attributes are
999 used to communicate additional information about the result or parameters of
1000 a function. Parameter attributes are considered to be part of the function,
1001 not of the function type, so functions with different parameter attributes
1002 can have the same function type.</p>
1003
1004<p>Parameter attributes are simple keywords that follow the type specified. If
1005 multiple parameter attributes are needed, they are space separated. For
1006 example:</p>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]1007
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]1008<pre class="doc_code">
Nick Lewyckydac78d82009-02-15 23:06:14 +0000[diff] [blame]1009declare i32 @printf(i8* noalias nocapture, ...)
Chris Lattnerd2597d72008-10-04 18:33:34 +0000[diff] [blame]1010declare i32 @atoi(i8 zeroext)
1011declare signext i8 @returns_signed_char()
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]1012</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]1013
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1014<p>Note that any attributes for the function result (<tt>nounwind</tt>,
1015 <tt>readonly</tt>) come immediately after the argument list.</p>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1016
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1017<p>Currently, only the following parameter attributes are defined:</p>
Chris Lattner5cee13f2008-01-11 06:20:47 +0000[diff] [blame]1018
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1019<dl>
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1020 <dt><tt><b>zeroext</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1021 <dd>This indicates to the code generator that the parameter or return value
Cameron Zwarichac106272011-03-16 22:20:18 +0000[diff] [blame]1022 should be zero-extended to the extent required by the target's ABI (which
1023 is usually 32-bits, but is 8-bits for a i1 on x86-64) by the caller (for a
1024 parameter) or the callee (for a return value).</dd>
Chris Lattner5cee13f2008-01-11 06:20:47 +0000[diff] [blame]1025
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1026 <dt><tt><b>signext</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1027 <dd>This indicates to the code generator that the parameter or return value
Cameron Zwarich341c36d2011-03-17 14:21:58 +0000[diff] [blame]1028 should be sign-extended to the extent required by the target's ABI (which
1029 is usually 32-bits) by the caller (for a parameter) or the callee (for a
1030 return value).</dd>
Chris Lattner5cee13f2008-01-11 06:20:47 +0000[diff] [blame]1031
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1032 <dt><tt><b>inreg</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1033 <dd>This indicates that this parameter or return value should be treated in a
1034 special target-dependent fashion during while emitting code for a function
1035 call or return (usually, by putting it in a register as opposed to memory,
1036 though some targets use it to distinguish between two different kinds of
1037 registers). Use of this attribute is target-specific.</dd>
Chris Lattner5cee13f2008-01-11 06:20:47 +0000[diff] [blame]1038
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1039 <dt><tt><b><a name="byval">byval</a></b></tt></dt>
Chris Lattnerd78dbee2010-11-20 23:49:06 +0000[diff] [blame]1040 <dd><p>This indicates that the pointer parameter should really be passed by
1041 value to the function. The attribute implies that a hidden copy of the
1042 pointee
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1043 is made between the caller and the callee, so the callee is unable to
1044 modify the value in the callee. This attribute is only valid on LLVM
1045 pointer arguments. It is generally used to pass structs and arrays by
1046 value, but is also valid on pointers to scalars. The copy is considered
1047 to belong to the caller not the callee (for example,
1048 <tt><a href="#readonly">readonly</a></tt> functions should not write to
1049 <tt>byval</tt> parameters). This is not a valid attribute for return
Chris Lattnerd78dbee2010-11-20 23:49:06 +0000[diff] [blame]1050 values.</p>
1051
1052 <p>The byval attribute also supports specifying an alignment with
1053 the align attribute. It indicates the alignment of the stack slot to
1054 form and the known alignment of the pointer specified to the call site. If
1055 the alignment is not specified, then the code generator makes a
1056 target-specific assumption.</p></dd>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1057
Dan Gohman3770af52010-07-02 23:18:08 +0000[diff] [blame]1058 <dt><tt><b><a name="sret">sret</a></b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1059 <dd>This indicates that the pointer parameter specifies the address of a
1060 structure that is the return value of the function in the source program.
1061 This pointer must be guaranteed by the caller to be valid: loads and
1062 stores to the structure may be assumed by the callee to not to trap. This
1063 may only be applied to the first parameter. This is not a valid attribute
1064 for return values. </dd>
1065
Dan Gohman3770af52010-07-02 23:18:08 +0000[diff] [blame]1066 <dt><tt><b><a name="noalias">noalias</a></b></tt></dt>
Dan Gohmandf12d082010-07-02 18:41:32 +0000[diff] [blame]1067 <dd>This indicates that pointer values
1068 <a href="#pointeraliasing"><i>based</i></a> on the argument or return
Dan Gohmande256292010-07-02 23:46:54 +0000[diff] [blame]1069 value do not alias pointer values which are not <i>based</i> on it,
1070 ignoring certain "irrelevant" dependencies.
1071 For a call to the parent function, dependencies between memory
1072 references from before or after the call and from those during the call
1073 are "irrelevant" to the <tt>noalias</tt> keyword for the arguments and
1074 return value used in that call.
Dan Gohmandf12d082010-07-02 18:41:32 +0000[diff] [blame]1075 The caller shares the responsibility with the callee for ensuring that
1076 these requirements are met.
1077 For further details, please see the discussion of the NoAlias response in
Dan Gohman6c858db2010-07-06 15:26:33 +0000[diff] [blame]1078 <a href="AliasAnalysis.html#MustMayNo">alias analysis</a>.<br>
1079<br>
John McCall72ed8902010-07-06 21:07:14 +0000[diff] [blame]1080 Note that this definition of <tt>noalias</tt> is intentionally
1081 similar to the definition of <tt>restrict</tt> in C99 for function
Chris Lattner5eff9ca2010-07-06 20:51:35 +0000[diff] [blame]1082 arguments, though it is slightly weaker.
Dan Gohman6c858db2010-07-06 15:26:33 +0000[diff] [blame]1083<br>
1084 For function return values, C99's <tt>restrict</tt> is not meaningful,
1085 while LLVM's <tt>noalias</tt> is.
1086 </dd>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1087
Dan Gohman3770af52010-07-02 23:18:08 +0000[diff] [blame]1088 <dt><tt><b><a name="nocapture">nocapture</a></b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1089 <dd>This indicates that the callee does not make any copies of the pointer
1090 that outlive the callee itself. This is not a valid attribute for return
1091 values.</dd>
1092
Dan Gohman3770af52010-07-02 23:18:08 +0000[diff] [blame]1093 <dt><tt><b><a name="nest">nest</a></b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1094 <dd>This indicates that the pointer parameter can be excised using the
1095 <a href="#int_trampoline">trampoline intrinsics</a>. This is not a valid
1096 attribute for return values.</dd>
1097</dl>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1098
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1099</div>
1100
1101<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1102<h3>
Gordon Henriksen71183b62007-12-10 03:18:06 +0000[diff] [blame]1103 <a name="gc">Garbage Collector Names</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1104</h3>
Gordon Henriksen71183b62007-12-10 03:18:06 +0000[diff] [blame]1105
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1106<div>
Gordon Henriksen71183b62007-12-10 03:18:06 +0000[diff] [blame]1107
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1108<p>Each function may specify a garbage collector name, which is simply a
1109 string:</p>
1110
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]1111<pre class="doc_code">
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1112define void @f() gc "name" { ... }
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1113</pre>
Gordon Henriksen71183b62007-12-10 03:18:06 +0000[diff] [blame]1114
1115<p>The compiler declares the supported values of <i>name</i>. Specifying a
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1116 collector which will cause the compiler to alter its output in order to
1117 support the named garbage collection algorithm.</p>
1118
Gordon Henriksen71183b62007-12-10 03:18:06 +0000[diff] [blame]1119</div>
1120
1121<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1122<h3>
Devang Patel9eb525d2008-09-26 23:51:19 +0000[diff] [blame]1123 <a name="fnattrs">Function Attributes</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1124</h3>
Devang Patelcaacdba2008-09-04 23:05:13 +0000[diff] [blame]1125
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1126<div>
Devang Patel9eb525d2008-09-26 23:51:19 +0000[diff] [blame]1127
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1128<p>Function attributes are set to communicate additional information about a
1129 function. Function attributes are considered to be part of the function, not
1130 of the function type, so functions with different parameter attributes can
1131 have the same function type.</p>
Devang Patel9eb525d2008-09-26 23:51:19 +0000[diff] [blame]1132
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1133<p>Function attributes are simple keywords that follow the type specified. If
1134 multiple attributes are needed, they are space separated. For example:</p>
Devang Patelcaacdba2008-09-04 23:05:13 +0000[diff] [blame]1135
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]1136<pre class="doc_code">
Devang Patel9eb525d2008-09-26 23:51:19 +0000[diff] [blame]1137define void @f() noinline { ... }
1138define void @f() alwaysinline { ... }
1139define void @f() alwaysinline optsize { ... }
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1140define void @f() optsize { ... }
Bill Wendlingb175fa42008-09-07 10:26:33 +0000[diff] [blame]1141</pre>
Devang Patelcaacdba2008-09-04 23:05:13 +0000[diff] [blame]1142
Bill Wendlingb175fa42008-09-07 10:26:33 +0000[diff] [blame]1143<dl>
Charles Davisbe5557e2010-02-12 00:31:15 +0000[diff] [blame]1144 <dt><tt><b>alignstack(&lt;<em>n</em>&gt;)</b></tt></dt>
1145 <dd>This attribute indicates that, when emitting the prologue and epilogue,
1146 the backend should forcibly align the stack pointer. Specify the
1147 desired alignment, which must be a power of two, in parentheses.
1148
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1149 <dt><tt><b>alwaysinline</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1150 <dd>This attribute indicates that the inliner should attempt to inline this
1151 function into callers whenever possible, ignoring any active inlining size
1152 threshold for this caller.</dd>
Bill Wendlingb175fa42008-09-07 10:26:33 +0000[diff] [blame]1153
Dan Gohman8bd11f12011-06-16 16:03:13 +0000[diff] [blame]1154 <dt><tt><b>nonlazybind</b></tt></dt>
1155 <dd>This attribute suppresses lazy symbol binding for the function. This
1156 may make calls to the function faster, at the cost of extra program
1157 startup time if the function is not called during program startup.</dd>
1158
Jakob Stoklund Olesen74bb06c2010-02-06 01:16:28 +0000[diff] [blame]1159 <dt><tt><b>inlinehint</b></tt></dt>
1160 <dd>This attribute indicates that the source code contained a hint that inlining
1161 this function is desirable (such as the "inline" keyword in C/C++). It
1162 is just a hint; it imposes no requirements on the inliner.</dd>
1163
Nick Lewycky14b58da2010-07-06 18:24:09 +0000[diff] [blame]1164 <dt><tt><b>naked</b></tt></dt>
1165 <dd>This attribute disables prologue / epilogue emission for the function.
1166 This can have very system-specific consequences.</dd>
1167
1168 <dt><tt><b>noimplicitfloat</b></tt></dt>
1169 <dd>This attributes disables implicit floating point instructions.</dd>
1170
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1171 <dt><tt><b>noinline</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1172 <dd>This attribute indicates that the inliner should never inline this
1173 function in any situation. This attribute may not be used together with
1174 the <tt>alwaysinline</tt> attribute.</dd>
Devang Patel9eb525d2008-09-26 23:51:19 +0000[diff] [blame]1175
Nick Lewycky14b58da2010-07-06 18:24:09 +0000[diff] [blame]1176 <dt><tt><b>noredzone</b></tt></dt>
1177 <dd>This attribute indicates that the code generator should not use a red
1178 zone, even if the target-specific ABI normally permits it.</dd>
Devang Patel9eb525d2008-09-26 23:51:19 +0000[diff] [blame]1179
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1180 <dt><tt><b>noreturn</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1181 <dd>This function attribute indicates that the function never returns
1182 normally. This produces undefined behavior at runtime if the function
1183 ever does dynamically return.</dd>
Bill Wendlinga8130172008-11-13 01:02:51 +0000[diff] [blame]1184
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1185 <dt><tt><b>nounwind</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1186 <dd>This function attribute indicates that the function never returns with an
1187 unwind or exceptional control flow. If the function does unwind, its
1188 runtime behavior is undefined.</dd>
Bill Wendling0f5541e2008-11-26 19:07:40 +0000[diff] [blame]1189
Nick Lewycky14b58da2010-07-06 18:24:09 +0000[diff] [blame]1190 <dt><tt><b>optsize</b></tt></dt>
1191 <dd>This attribute suggests that optimization passes and code generator passes
1192 make choices that keep the code size of this function low, and otherwise
1193 do optimizations specifically to reduce code size.</dd>
1194
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1195 <dt><tt><b>readnone</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1196 <dd>This attribute indicates that the function computes its result (or decides
1197 to unwind an exception) based strictly on its arguments, without
1198 dereferencing any pointer arguments or otherwise accessing any mutable
1199 state (e.g. memory, control registers, etc) visible to caller functions.
1200 It does not write through any pointer arguments
1201 (including <tt><a href="#byval">byval</a></tt> arguments) and never
1202 changes any state visible to callers. This means that it cannot unwind
1203 exceptions by calling the <tt>C++</tt> exception throwing methods, but
1204 could use the <tt>unwind</tt> instruction.</dd>
Devang Patel310fd4a2009-06-12 19:45:19 +0000[diff] [blame]1205
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1206 <dt><tt><b><a name="readonly">readonly</a></b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1207 <dd>This attribute indicates that the function does not write through any
1208 pointer arguments (including <tt><a href="#byval">byval</a></tt>
1209 arguments) or otherwise modify any state (e.g. memory, control registers,
1210 etc) visible to caller functions. It may dereference pointer arguments
1211 and read state that may be set in the caller. A readonly function always
1212 returns the same value (or unwinds an exception identically) when called
1213 with the same set of arguments and global state. It cannot unwind an
1214 exception by calling the <tt>C++</tt> exception throwing methods, but may
1215 use the <tt>unwind</tt> instruction.</dd>
Anton Korobeynikovc8ce7b082009-07-17 18:07:26 +0000[diff] [blame]1216
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1217 <dt><tt><b><a name="ssp">ssp</a></b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1218 <dd>This attribute indicates that the function should emit a stack smashing
1219 protector. It is in the form of a "canary"&mdash;a random value placed on
1220 the stack before the local variables that's checked upon return from the
1221 function to see if it has been overwritten. A heuristic is used to
1222 determine if a function needs stack protectors or not.<br>
1223<br>
1224 If a function that has an <tt>ssp</tt> attribute is inlined into a
1225 function that doesn't have an <tt>ssp</tt> attribute, then the resulting
1226 function will have an <tt>ssp</tt> attribute.</dd>
1227
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1228 <dt><tt><b>sspreq</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1229 <dd>This attribute indicates that the function should <em>always</em> emit a
1230 stack smashing protector. This overrides
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1231 the <tt><a href="#ssp">ssp</a></tt> function attribute.<br>
1232<br>
1233 If a function that has an <tt>sspreq</tt> attribute is inlined into a
1234 function that doesn't have an <tt>sspreq</tt> attribute or which has
1235 an <tt>ssp</tt> attribute, then the resulting function will have
1236 an <tt>sspreq</tt> attribute.</dd>
Rafael Espindola163d6752011-07-25 15:27:59 +0000[diff] [blame]1237
1238 <dt><tt><b><a name="uwtable">uwtable</a></b></tt></dt>
1239 <dd>This attribute indicates that the ABI being targeted requires that
1240 an unwind table entry be produce for this function even if we can
1241 show that no exceptions passes by it. This is normally the case for
1242 the ELF x86-64 abi, but it can be disabled for some compilation
1243 units.</dd>
1244
Rafael Espindolacc349c82011-10-03 14:45:37 +0000[diff] [blame]1245 <dt><tt><b><a name="returns_twice">returns_twice</a></b></tt></dt>
1246 <dd>This attribute indicates that this function can return
1247 twice. The C <code>setjmp</code> is an example of such a function.
1248 The compiler disables some optimizations (like tail calls) in the caller of
1249 these functions.</dd>
Bill Wendlingb175fa42008-09-07 10:26:33 +0000[diff] [blame]1250</dl>
1251
Devang Patelcaacdba2008-09-04 23:05:13 +0000[diff] [blame]1252</div>
1253
1254<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1255<h3>
Chris Lattner93564892006-04-08 04:40:53 +0000[diff] [blame]1256 <a name="moduleasm">Module-Level Inline Assembly</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1257</h3>
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]1258
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1259<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1260
1261<p>Modules may contain "module-level inline asm" blocks, which corresponds to
1262 the GCC "file scope inline asm" blocks. These blocks are internally
1263 concatenated by LLVM and treated as a single unit, but may be separated in
1264 the <tt>.ll</tt> file if desired. The syntax is very simple:</p>
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]1265
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]1266<pre class="doc_code">
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]1267module asm "inline asm code goes here"
1268module asm "more can go here"
1269</pre>
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]1270
1271<p>The strings can contain any character by escaping non-printable characters.
1272 The escape sequence used is simply "\xx" where "xx" is the two digit hex code
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1273 for the number.</p>
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]1274
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1275<p>The inline asm code is simply printed to the machine code .s file when
1276 assembly code is generated.</p>
1277
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]1278</div>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]1279
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1280<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1281<h3>
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1282 <a name="datalayout">Data Layout</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1283</h3>
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1284
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1285<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1286
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1287<p>A module may specify a target specific data layout string that specifies how
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1288 data is to be laid out in memory. The syntax for the data layout is
1289 simply:</p>
1290
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]1291<pre class="doc_code">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1292target datalayout = "<i>layout specification</i>"
1293</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1294
1295<p>The <i>layout specification</i> consists of a list of specifications
1296 separated by the minus sign character ('-'). Each specification starts with
1297 a letter and may include other information after the letter to define some
1298 aspect of the data layout. The specifications accepted are as follows:</p>
1299
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1300<dl>
1301 <dt><tt>E</tt></dt>
1302 <dd>Specifies that the target lays out data in big-endian form. That is, the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1303 bits with the most significance have the lowest address location.</dd>
1304
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1305 <dt><tt>e</tt></dt>
Chris Lattner67c37d12008-08-05 18:29:16 +0000[diff] [blame]1306 <dd>Specifies that the target lays out data in little-endian form. That is,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1307 the bits with the least significance have the lowest address
1308 location.</dd>
1309
Lang Hamesde7ab802011-10-10 23:42:08 +0000[diff] [blame]1310 <dt><tt>S<i>size</i></tt></dt>
1311 <dd>Specifies the natural alignment of the stack in bits. Alignment promotion
1312 of stack variables is limited to the natural stack alignment to avoid
1313 dynamic stack realignment. The stack alignment must be a multiple of
Lang Hamesff2c52c2011-10-11 17:50:14 +0000[diff] [blame]1314 8-bits. If omitted, the natural stack alignment defaults to "unspecified",
1315 which does not prevent any alignment promotions.</dd>
Lang Hamesde7ab802011-10-10 23:42:08 +0000[diff] [blame]1316
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1317 <dt><tt>p:<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]1318 <dd>This specifies the <i>size</i> of a pointer and its <i>abi</i> and
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1319 <i>preferred</i> alignments. All sizes are in bits. Specifying
1320 the <i>pref</i> alignment is optional. If omitted, the
1321 preceding <tt>:</tt> should be omitted too.</dd>
1322
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1323 <dt><tt>i<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1324 <dd>This specifies the alignment for an integer type of a given bit
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1325 <i>size</i>. The value of <i>size</i> must be in the range [1,2^23).</dd>
1326
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1327 <dt><tt>v<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]1328 <dd>This specifies the alignment for a vector type of a given bit
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1329 <i>size</i>.</dd>
1330
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1331 <dt><tt>f<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]1332 <dd>This specifies the alignment for a floating point type of a given bit
Dale Johannesence522852010-05-28 18:54:47 +0000[diff] [blame]1333 <i>size</i>. Only values of <i>size</i> that are supported by the target
1334 will work. 32 (float) and 64 (double) are supported on all targets;
1335 80 or 128 (different flavors of long double) are also supported on some
1336 targets.
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1337
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1338 <dt><tt>a<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1339 <dd>This specifies the alignment for an aggregate type of a given bit
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1340 <i>size</i>.</dd>
1341
Daniel Dunbar7921a592009-06-08 22:17:53 +0000[diff] [blame]1342 <dt><tt>s<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1343 <dd>This specifies the alignment for a stack object of a given bit
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1344 <i>size</i>.</dd>
Chris Lattnera381eff2009-11-07 09:35:34 +0000[diff] [blame]1345
1346 <dt><tt>n<i>size1</i>:<i>size2</i>:<i>size3</i>...</tt></dt>
1347 <dd>This specifies a set of native integer widths for the target CPU
1348 in bits. For example, it might contain "n32" for 32-bit PowerPC,
1349 "n32:64" for PowerPC 64, or "n8:16:32:64" for X86-64. Elements of
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]1350 this set are considered to support most general arithmetic
Chris Lattnera381eff2009-11-07 09:35:34 +0000[diff] [blame]1351 operations efficiently.</dd>
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1352</dl>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1353
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1354<p>When constructing the data layout for a given target, LLVM starts with a
Dan Gohman61110ae2010-04-28 00:36:01 +0000[diff] [blame]1355 default set of specifications which are then (possibly) overridden by the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1356 specifications in the <tt>datalayout</tt> keyword. The default specifications
1357 are given in this list:</p>
1358
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1359<ul>
1360 <li><tt>E</tt> - big endian</li>
Dan Gohman8ad777d2010-02-23 02:44:03 +0000[diff] [blame]1361 <li><tt>p:64:64:64</tt> - 64-bit pointers with 64-bit alignment</li>
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1362 <li><tt>i1:8:8</tt> - i1 is 8-bit (byte) aligned</li>
1363 <li><tt>i8:8:8</tt> - i8 is 8-bit (byte) aligned</li>
1364 <li><tt>i16:16:16</tt> - i16 is 16-bit aligned</li>
1365 <li><tt>i32:32:32</tt> - i32 is 32-bit aligned</li>
Chris Lattner67c37d12008-08-05 18:29:16 +0000[diff] [blame]1366 <li><tt>i64:32:64</tt> - i64 has ABI alignment of 32-bits but preferred
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1367 alignment of 64-bits</li>
1368 <li><tt>f32:32:32</tt> - float is 32-bit aligned</li>
1369 <li><tt>f64:64:64</tt> - double is 64-bit aligned</li>
1370 <li><tt>v64:64:64</tt> - 64-bit vector is 64-bit aligned</li>
1371 <li><tt>v128:128:128</tt> - 128-bit vector is 128-bit aligned</li>
1372 <li><tt>a0:0:1</tt> - aggregates are 8-bit aligned</li>
Daniel Dunbar7921a592009-06-08 22:17:53 +0000[diff] [blame]1373 <li><tt>s0:64:64</tt> - stack objects are 64-bit aligned</li>
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1374</ul>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1375
1376<p>When LLVM is determining the alignment for a given type, it uses the
1377 following rules:</p>
1378
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1379<ol>
1380 <li>If the type sought is an exact match for one of the specifications, that
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1381 specification is used.</li>
1382
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1383 <li>If no match is found, and the type sought is an integer type, then the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1384 smallest integer type that is larger than the bitwidth of the sought type
1385 is used. If none of the specifications are larger than the bitwidth then
1386 the the largest integer type is used. For example, given the default
1387 specifications above, the i7 type will use the alignment of i8 (next
1388 largest) while both i65 and i256 will use the alignment of i64 (largest
1389 specified).</li>
1390
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1391 <li>If no match is found, and the type sought is a vector type, then the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1392 largest vector type that is smaller than the sought vector type will be
1393 used as a fall back. This happens because &lt;128 x double&gt; can be
1394 implemented in terms of 64 &lt;2 x double&gt;, for example.</li>
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1395</ol>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1396
Chris Lattner48797402011-10-11 23:01:39 +0000[diff] [blame]1397<p>The function of the data layout string may not be what you expect. Notably,
1398 this is not a specification from the frontend of what alignment the code
1399 generator should use.</p>
1400
1401<p>Instead, if specified, the target data layout is required to match what the
1402 ultimate <em>code generator</em> expects. This string is used by the
1403 mid-level optimizers to
1404 improve code, and this only works if it matches what the ultimate code
1405 generator uses. If you would like to generate IR that does not embed this
1406 target-specific detail into the IR, then you don't have to specify the
1407 string. This will disable some optimizations that require precise layout
1408 information, but this also prevents those optimizations from introducing
1409 target specificity into the IR.</p>
1410
1411
1412
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1413</div>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]1414
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1415<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1416<h3>
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1417 <a name="pointeraliasing">Pointer Aliasing Rules</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1418</h3>
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1419
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1420<div>
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1421
Andreas Bolka8ae4e242009-07-29 00:02:05 +0000[diff] [blame]1422<p>Any memory access must be done through a pointer value associated
Andreas Bolkae39f0332009-07-27 20:37:10 +0000[diff] [blame]1423with an address range of the memory access, otherwise the behavior
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1424is undefined. Pointer values are associated with address ranges
1425according to the following rules:</p>
1426
1427<ul>
Dan Gohmandf12d082010-07-02 18:41:32 +0000[diff] [blame]1428 <li>A pointer value is associated with the addresses associated with
1429 any value it is <i>based</i> on.
Andreas Bolka8ae4e242009-07-29 00:02:05 +0000[diff] [blame]1430 <li>An address of a global variable is associated with the address
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1431 range of the variable's storage.</li>
1432 <li>The result value of an allocation instruction is associated with
1433 the address range of the allocated storage.</li>
1434 <li>A null pointer in the default address-space is associated with
Andreas Bolka8ae4e242009-07-29 00:02:05 +0000[diff] [blame]1435 no address.</li>
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1436 <li>An integer constant other than zero or a pointer value returned
1437 from a function not defined within LLVM may be associated with address
1438 ranges allocated through mechanisms other than those provided by
Andreas Bolka8ae4e242009-07-29 00:02:05 +0000[diff] [blame]1439 LLVM. Such ranges shall not overlap with any ranges of addresses
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1440 allocated by mechanisms provided by LLVM.</li>
Dan Gohmandf12d082010-07-02 18:41:32 +0000[diff] [blame]1441</ul>
1442
1443<p>A pointer value is <i>based</i> on another pointer value according
1444 to the following rules:</p>
1445
1446<ul>
1447 <li>A pointer value formed from a
1448 <tt><a href="#i_getelementptr">getelementptr</a></tt> operation
1449 is <i>based</i> on the first operand of the <tt>getelementptr</tt>.</li>
1450 <li>The result value of a
1451 <tt><a href="#i_bitcast">bitcast</a></tt> is <i>based</i> on the operand
1452 of the <tt>bitcast</tt>.</li>
1453 <li>A pointer value formed by an
1454 <tt><a href="#i_inttoptr">inttoptr</a></tt> is <i>based</i> on all
1455 pointer values that contribute (directly or indirectly) to the
1456 computation of the pointer's value.</li>
1457 <li>The "<i>based</i> on" relationship is transitive.</li>
1458</ul>
1459
1460<p>Note that this definition of <i>"based"</i> is intentionally
1461 similar to the definition of <i>"based"</i> in C99, though it is
1462 slightly weaker.</p>
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1463
1464<p>LLVM IR does not associate types with memory. The result type of a
Andreas Bolka8ae4e242009-07-29 00:02:05 +0000[diff] [blame]1465<tt><a href="#i_load">load</a></tt> merely indicates the size and
1466alignment of the memory from which to load, as well as the
Dan Gohman4eb47192010-06-17 19:23:50 +0000[diff] [blame]1467interpretation of the value. The first operand type of a
Andreas Bolka8ae4e242009-07-29 00:02:05 +0000[diff] [blame]1468<tt><a href="#i_store">store</a></tt> similarly only indicates the size
1469and alignment of the store.</p>
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1470
1471<p>Consequently, type-based alias analysis, aka TBAA, aka
1472<tt>-fstrict-aliasing</tt>, is not applicable to general unadorned
1473LLVM IR. <a href="#metadata">Metadata</a> may be used to encode
1474additional information which specialized optimization passes may use
1475to implement type-based alias analysis.</p>
1476
1477</div>
1478
Jeffrey Yasskin5d284ae2010-04-26 21:21:24 +0000[diff] [blame]1479<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1480<h3>
Jeffrey Yasskin5d284ae2010-04-26 21:21:24 +0000[diff] [blame]1481 <a name="volatile">Volatile Memory Accesses</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1482</h3>
Jeffrey Yasskin5d284ae2010-04-26 21:21:24 +0000[diff] [blame]1483
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1484<div>
Jeffrey Yasskin5d284ae2010-04-26 21:21:24 +0000[diff] [blame]1485
1486<p>Certain memory accesses, such as <a href="#i_load"><tt>load</tt></a>s, <a
1487href="#i_store"><tt>store</tt></a>s, and <a
1488href="#int_memcpy"><tt>llvm.memcpy</tt></a>s may be marked <tt>volatile</tt>.
1489The optimizers must not change the number of volatile operations or change their
1490order of execution relative to other volatile operations. The optimizers
1491<i>may</i> change the order of volatile operations relative to non-volatile
1492operations. This is not Java's "volatile" and has no cross-thread
1493synchronization behavior.</p>
1494
1495</div>
1496
Eli Friedman35b54aa2011-07-20 21:35:53 +0000[diff] [blame]1497<!-- ======================================================================= -->
1498<h3>
1499 <a name="memmodel">Memory Model for Concurrent Operations</a>
1500</h3>
1501
1502<div>
1503
1504<p>The LLVM IR does not define any way to start parallel threads of execution
1505or to register signal handlers. Nonetheless, there are platform-specific
1506ways to create them, and we define LLVM IR's behavior in their presence. This
1507model is inspired by the C++0x memory model.</p>
1508
Eli Friedman95f69a42011-08-22 21:35:27 +0000[diff] [blame]1509<p>For a more informal introduction to this model, see the
1510<a href="Atomics.html">LLVM Atomic Instructions and Concurrency Guide</a>.
1511
Eli Friedman35b54aa2011-07-20 21:35:53 +0000[diff] [blame]1512<p>We define a <i>happens-before</i> partial order as the least partial order
1513that</p>
1514<ul>
1515 <li>Is a superset of single-thread program order, and</li>
1516 <li>When a <i>synchronizes-with</i> <tt>b</tt>, includes an edge from
1517 <tt>a</tt> to <tt>b</tt>. <i>Synchronizes-with</i> pairs are introduced
1518 by platform-specific techniques, like pthread locks, thread
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]1519 creation, thread joining, etc., and by atomic instructions.
1520 (See also <a href="#ordering">Atomic Memory Ordering Constraints</a>).
1521 </li>
Eli Friedman35b54aa2011-07-20 21:35:53 +0000[diff] [blame]1522</ul>
1523
1524<p>Note that program order does not introduce <i>happens-before</i> edges
1525between a thread and signals executing inside that thread.</p>
1526
1527<p>Every (defined) read operation (load instructions, memcpy, atomic
1528loads/read-modify-writes, etc.) <var>R</var> reads a series of bytes written by
1529(defined) write operations (store instructions, atomic
Eli Friedmanf12e4e92011-07-22 03:04:45 +0000[diff] [blame]1530stores/read-modify-writes, memcpy, etc.). For the purposes of this section,
1531initialized globals are considered to have a write of the initializer which is
1532atomic and happens before any other read or write of the memory in question.
1533For each byte of a read <var>R</var>, <var>R<sub>byte</sub></var> may see
1534any write to the same byte, except:</p>
Eli Friedman35b54aa2011-07-20 21:35:53 +0000[diff] [blame]1535
1536<ul>
1537 <li>If <var>write<sub>1</sub></var> happens before
1538 <var>write<sub>2</sub></var>, and <var>write<sub>2</sub></var> happens
1539 before <var>R<sub>byte</sub></var>, then <var>R<sub>byte</sub></var>
Eli Friedmanf12e4e92011-07-22 03:04:45 +0000[diff] [blame]1540 does not see <var>write<sub>1</sub></var>.
Bill Wendling537603b2011-07-31 06:45:03 +0000[diff] [blame]1541 <li>If <var>R<sub>byte</sub></var> happens before
1542 <var>write<sub>3</sub></var>, then <var>R<sub>byte</sub></var> does not
1543 see <var>write<sub>3</sub></var>.
Eli Friedman35b54aa2011-07-20 21:35:53 +0000[diff] [blame]1544</ul>
1545
1546<p>Given that definition, <var>R<sub>byte</sub></var> is defined as follows:
1547<ul>
Eli Friedman95f69a42011-08-22 21:35:27 +0000[diff] [blame]1548 <li>If <var>R</var> is volatile, the result is target-dependent. (Volatile
1549 is supposed to give guarantees which can support
1550 <code>sig_atomic_t</code> in C/C++, and may be used for accesses to
1551 addresses which do not behave like normal memory. It does not generally
1552 provide cross-thread synchronization.)
1553 <li>Otherwise, if there is no write to the same byte that happens before
Eli Friedman35b54aa2011-07-20 21:35:53 +0000[diff] [blame]1554 <var>R<sub>byte</sub></var>, <var>R<sub>byte</sub></var> returns
1555 <tt>undef</tt> for that byte.
Eli Friedmanf12e4e92011-07-22 03:04:45 +0000[diff] [blame]1556 <li>Otherwise, if <var>R<sub>byte</sub></var> may see exactly one write,
Eli Friedman35b54aa2011-07-20 21:35:53 +0000[diff] [blame]1557 <var>R<sub>byte</sub></var> returns the value written by that
1558 write.</li>
Eli Friedmanf12e4e92011-07-22 03:04:45 +0000[diff] [blame]1559 <li>Otherwise, if <var>R</var> is atomic, and all the writes
1560 <var>R<sub>byte</sub></var> may see are atomic, it chooses one of the
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]1561 values written. See the <a href="#ordering">Atomic Memory Ordering
1562 Constraints</a> section for additional constraints on how the choice
1563 is made.
Eli Friedman35b54aa2011-07-20 21:35:53 +0000[diff] [blame]1564 <li>Otherwise <var>R<sub>byte</sub></var> returns <tt>undef</tt>.</li>
1565</ul>
1566
1567<p><var>R</var> returns the value composed of the series of bytes it read.
1568This implies that some bytes within the value may be <tt>undef</tt>
1569<b>without</b> the entire value being <tt>undef</tt>. Note that this only
1570defines the semantics of the operation; it doesn't mean that targets will
1571emit more than one instruction to read the series of bytes.</p>
1572
1573<p>Note that in cases where none of the atomic intrinsics are used, this model
1574places only one restriction on IR transformations on top of what is required
1575for single-threaded execution: introducing a store to a byte which might not
Eli Friedman4bc9f3c2011-08-02 01:15:34 +0000[diff] [blame]1576otherwise be stored is not allowed in general. (Specifically, in the case
1577where another thread might write to and read from an address, introducing a
1578store can change a load that may see exactly one write into a load that may
1579see multiple writes.)</p>
Eli Friedman35b54aa2011-07-20 21:35:53 +0000[diff] [blame]1580
1581<!-- FIXME: This model assumes all targets where concurrency is relevant have
1582a byte-size store which doesn't affect adjacent bytes. As far as I can tell,
1583none of the backends currently in the tree fall into this category; however,
1584there might be targets which care. If there are, we want a paragraph
1585like the following:
1586
1587Targets may specify that stores narrower than a certain width are not
1588available; on such a target, for the purposes of this model, treat any
1589non-atomic write with an alignment or width less than the minimum width
1590as if it writes to the relevant surrounding bytes.
1591-->
1592
1593</div>
1594
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]1595<!-- ======================================================================= -->
NAKAMURA Takumi0300d882011-08-12 06:17:17 +0000[diff] [blame]1596<h3>
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]1597 <a name="ordering">Atomic Memory Ordering Constraints</a>
NAKAMURA Takumi0300d882011-08-12 06:17:17 +0000[diff] [blame]1598</h3>
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]1599
NAKAMURA Takumi0300d882011-08-12 06:17:17 +0000[diff] [blame]1600<div>
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]1601
1602<p>Atomic instructions (<a href="#i_cmpxchg"><code>cmpxchg</code></a>,
Eli Friedman59b66882011-08-09 23:02:53 +0000[diff] [blame]1603<a href="#i_atomicrmw"><code>atomicrmw</code></a>,
1604<a href="#i_fence"><code>fence</code></a>,
1605<a href="#i_load"><code>atomic load</code></a>, and
Eli Friedman75362532011-08-09 23:26:12 +0000[diff] [blame]1606<a href="#i_store"><code>atomic store</code></a>) take an ordering parameter
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]1607that determines which other atomic instructions on the same address they
1608<i>synchronize with</i>. These semantics are borrowed from Java and C++0x,
1609but are somewhat more colloquial. If these descriptions aren't precise enough,
Eli Friedman95f69a42011-08-22 21:35:27 +0000[diff] [blame]1610check those specs (see spec references in the
1611<a href="Atomic.html#introduction">atomics guide</a>).
1612<a href="#i_fence"><code>fence</code></a> instructions
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]1613treat these orderings somewhat differently since they don't take an address.
1614See that instruction's documentation for details.</p>
1615
Eli Friedman95f69a42011-08-22 21:35:27 +0000[diff] [blame]1616<p>For a simpler introduction to the ordering constraints, see the
1617<a href="Atomics.html">LLVM Atomic Instructions and Concurrency Guide</a>.</p>
1618
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]1619<dl>
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]1620<dt><code>unordered</code></dt>
1621<dd>The set of values that can be read is governed by the happens-before
1622partial order. A value cannot be read unless some operation wrote it.
1623This is intended to provide a guarantee strong enough to model Java's
1624non-volatile shared variables. This ordering cannot be specified for
1625read-modify-write operations; it is not strong enough to make them atomic
1626in any interesting way.</dd>
1627<dt><code>monotonic</code></dt>
1628<dd>In addition to the guarantees of <code>unordered</code>, there is a single
1629total order for modifications by <code>monotonic</code> operations on each
1630address. All modification orders must be compatible with the happens-before
1631order. There is no guarantee that the modification orders can be combined to
1632a global total order for the whole program (and this often will not be
1633possible). The read in an atomic read-modify-write operation
1634(<a href="#i_cmpxchg"><code>cmpxchg</code></a> and
1635<a href="#i_atomicrmw"><code>atomicrmw</code></a>)
1636reads the value in the modification order immediately before the value it
1637writes. If one atomic read happens before another atomic read of the same
1638address, the later read must see the same value or a later value in the
1639address's modification order. This disallows reordering of
1640<code>monotonic</code> (or stronger) operations on the same address. If an
1641address is written <code>monotonic</code>ally by one thread, and other threads
1642<code>monotonic</code>ally read that address repeatedly, the other threads must
Eli Friedman95f69a42011-08-22 21:35:27 +0000[diff] [blame]1643eventually see the write. This corresponds to the C++0x/C1x
1644<code>memory_order_relaxed</code>.</dd>
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]1645<dt><code>acquire</code></dt>
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]1646<dd>In addition to the guarantees of <code>monotonic</code>,
Eli Friedman0cb3b562011-08-24 20:28:39 +0000[diff] [blame]1647a <i>synchronizes-with</i> edge may be formed with a <code>release</code>
1648operation. This is intended to model C++'s <code>memory_order_acquire</code>.</dd>
1649<dt><code>release</code></dt>
1650<dd>In addition to the guarantees of <code>monotonic</code>, if this operation
1651writes a value which is subsequently read by an <code>acquire</code> operation,
1652it <i>synchronizes-with</i> that operation. (This isn't a complete
1653description; see the C++0x definition of a release sequence.) This corresponds
1654to the C++0x/C1x <code>memory_order_release</code>.</dd>
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]1655<dt><code>acq_rel</code> (acquire+release)</dt><dd>Acts as both an
Eli Friedman95f69a42011-08-22 21:35:27 +0000[diff] [blame]1656<code>acquire</code> and <code>release</code> operation on its address.
1657This corresponds to the C++0x/C1x <code>memory_order_acq_rel</code>.</dd>
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]1658<dt><code>seq_cst</code> (sequentially consistent)</dt><dd>
1659<dd>In addition to the guarantees of <code>acq_rel</code>
1660(<code>acquire</code> for an operation which only reads, <code>release</code>
1661for an operation which only writes), there is a global total order on all
1662sequentially-consistent operations on all addresses, which is consistent with
1663the <i>happens-before</i> partial order and with the modification orders of
1664all the affected addresses. Each sequentially-consistent read sees the last
Eli Friedman95f69a42011-08-22 21:35:27 +0000[diff] [blame]1665preceding write to the same address in this global order. This corresponds
1666to the C++0x/C1x <code>memory_order_seq_cst</code> and Java volatile.</dd>
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]1667</dl>
1668
1669<p id="singlethread">If an atomic operation is marked <code>singlethread</code>,
1670it only <i>synchronizes with</i> or participates in modification and seq_cst
1671total orderings with other operations running in the same thread (for example,
1672in signal handlers).</p>
1673
1674</div>
1675
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1676</div>
1677
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1678<!-- *********************************************************************** -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1679<h2><a name="typesystem">Type System</a></h2>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1680<!-- *********************************************************************** -->
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]1681
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1682<div>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]1683
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1684<p>The LLVM type system is one of the most important features of the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1685 intermediate representation. Being typed enables a number of optimizations
1686 to be performed on the intermediate representation directly, without having
1687 to do extra analyses on the side before the transformation. A strong type
1688 system makes it easier to read the generated code and enables novel analyses
1689 and transformations that are not feasible to perform on normal three address
1690 code representations.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]1691
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1692<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1693<h3>
1694 <a name="t_classifications">Type Classifications</a>
1695</h3>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1696
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1697<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1698
1699<p>The types fall into a few useful classifications:</p>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]1700
1701<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1702 <tbody>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1703 <tr><th>Classification</th><th>Types</th></tr>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1704 <tr>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1705 <td><a href="#t_integer">integer</a></td>
Reid Spencer138249b2007-05-16 18:44:01 +0000[diff] [blame]1706 <td><tt>i1, i2, i3, ... i8, ... i16, ... i32, ... i64, ... </tt></td>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1707 </tr>
1708 <tr>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1709 <td><a href="#t_floating">floating point</a></td>
1710 <td><tt>float, double, x86_fp80, fp128, ppc_fp128</tt></td>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1711 </tr>
1712 <tr>
1713 <td><a name="t_firstclass">first class</a></td>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1714 <td><a href="#t_integer">integer</a>,
1715 <a href="#t_floating">floating point</a>,
1716 <a href="#t_pointer">pointer</a>,
Dan Gohman08783a882008-06-18 18:42:13 +0000[diff] [blame]1717 <a href="#t_vector">vector</a>,
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]1718 <a href="#t_struct">structure</a>,
1719 <a href="#t_array">array</a>,
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1720 <a href="#t_label">label</a>,
1721 <a href="#t_metadata">metadata</a>.
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1722 </td>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1723 </tr>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1724 <tr>
1725 <td><a href="#t_primitive">primitive</a></td>
1726 <td><a href="#t_label">label</a>,
1727 <a href="#t_void">void</a>,
Tobias Grosser4c8c95b2010-12-28 20:29:31 +0000[diff] [blame]1728 <a href="#t_integer">integer</a>,
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1729 <a href="#t_floating">floating point</a>,
Dale Johannesen33e5c352010-10-01 00:48:59 +0000[diff] [blame]1730 <a href="#t_x86mmx">x86mmx</a>,
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1731 <a href="#t_metadata">metadata</a>.</td>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1732 </tr>
1733 <tr>
1734 <td><a href="#t_derived">derived</a></td>
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]1735 <td><a href="#t_array">array</a>,
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1736 <a href="#t_function">function</a>,
1737 <a href="#t_pointer">pointer</a>,
1738 <a href="#t_struct">structure</a>,
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1739 <a href="#t_vector">vector</a>,
1740 <a href="#t_opaque">opaque</a>.
Dan Gohman93bf60d2008-10-14 16:32:04 +0000[diff] [blame]1741 </td>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1742 </tr>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1743 </tbody>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1744</table>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]1745
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1746<p>The <a href="#t_firstclass">first class</a> types are perhaps the most
1747 important. Values of these types are the only ones which can be produced by
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]1748 instructions.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1749
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1750</div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1751
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1752<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1753<h3>
1754 <a name="t_primitive">Primitive Types</a>
1755</h3>
Chris Lattner43542b32008-01-04 04:34:14 +0000[diff] [blame]1756
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1757<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1758
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1759<p>The primitive types are the fundamental building blocks of the LLVM
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1760 system.</p>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1761
1762<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1763<h4>
1764 <a name="t_integer">Integer Type</a>
1765</h4>
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]1766
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1767<div>
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]1768
1769<h5>Overview:</h5>
1770<p>The integer type is a very simple type that simply specifies an arbitrary
1771 bit width for the integer type desired. Any bit width from 1 bit to
1772 2<sup>23</sup>-1 (about 8 million) can be specified.</p>
1773
1774<h5>Syntax:</h5>
1775<pre>
1776 iN
1777</pre>
1778
1779<p>The number of bits the integer will occupy is specified by the <tt>N</tt>
1780 value.</p>
1781
1782<h5>Examples:</h5>
1783<table class="layout">
1784 <tr class="layout">
1785 <td class="left"><tt>i1</tt></td>
1786 <td class="left">a single-bit integer.</td>
1787 </tr>
1788 <tr class="layout">
1789 <td class="left"><tt>i32</tt></td>
1790 <td class="left">a 32-bit integer.</td>
1791 </tr>
1792 <tr class="layout">
1793 <td class="left"><tt>i1942652</tt></td>
1794 <td class="left">a really big integer of over 1 million bits.</td>
1795 </tr>
1796</table>
1797
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]1798</div>
1799
1800<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1801<h4>
1802 <a name="t_floating">Floating Point Types</a>
1803</h4>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1804
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1805<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1806
1807<table>
1808 <tbody>
1809 <tr><th>Type</th><th>Description</th></tr>
1810 <tr><td><tt>float</tt></td><td>32-bit floating point value</td></tr>
1811 <tr><td><tt>double</tt></td><td>64-bit floating point value</td></tr>
1812 <tr><td><tt>fp128</tt></td><td>128-bit floating point value (112-bit mantissa)</td></tr>
1813 <tr><td><tt>x86_fp80</tt></td><td>80-bit floating point value (X87)</td></tr>
1814 <tr><td><tt>ppc_fp128</tt></td><td>128-bit floating point value (two 64-bits)</td></tr>
1815 </tbody>
1816</table>
1817
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1818</div>
1819
1820<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1821<h4>
1822 <a name="t_x86mmx">X86mmx Type</a>
1823</h4>
Dale Johannesen33e5c352010-10-01 00:48:59 +0000[diff] [blame]1824
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1825<div>
Dale Johannesen33e5c352010-10-01 00:48:59 +0000[diff] [blame]1826
1827<h5>Overview:</h5>
1828<p>The x86mmx type represents a value held in an MMX register on an x86 machine. The operations allowed on it are quite limited: parameters and return values, load and store, and bitcast. User-specified MMX instructions are represented as intrinsic or asm calls with arguments and/or results of this type. There are no arrays, vectors or constants of this type.</p>
1829
1830<h5>Syntax:</h5>
1831<pre>
Dale Johannesenb1f0ff12010-10-01 01:07:02 +0000[diff] [blame]1832 x86mmx
Dale Johannesen33e5c352010-10-01 00:48:59 +0000[diff] [blame]1833</pre>
1834
1835</div>
1836
1837<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1838<h4>
1839 <a name="t_void">Void Type</a>
1840</h4>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1841
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1842<div>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1843
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1844<h5>Overview:</h5>
1845<p>The void type does not represent any value and has no size.</p>
1846
1847<h5>Syntax:</h5>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1848<pre>
1849 void
1850</pre>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1851
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1852</div>
1853
1854<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1855<h4>
1856 <a name="t_label">Label Type</a>
1857</h4>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1858
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1859<div>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1860
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1861<h5>Overview:</h5>
1862<p>The label type represents code labels.</p>
1863
1864<h5>Syntax:</h5>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1865<pre>
1866 label
1867</pre>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1868
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1869</div>
1870
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1871<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1872<h4>
1873 <a name="t_metadata">Metadata Type</a>
1874</h4>
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1875
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1876<div>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1877
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1878<h5>Overview:</h5>
Nick Lewycky93e06a52009-09-27 23:27:42 +0000[diff] [blame]1879<p>The metadata type represents embedded metadata. No derived types may be
1880 created from metadata except for <a href="#t_function">function</a>
1881 arguments.
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1882
1883<h5>Syntax:</h5>
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1884<pre>
1885 metadata
1886</pre>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1887
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1888</div>
1889
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1890</div>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1891
1892<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1893<h3>
1894 <a name="t_derived">Derived Types</a>
1895</h3>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1896
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1897<div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1898
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1899<p>The real power in LLVM comes from the derived types in the system. This is
1900 what allows a programmer to represent arrays, functions, pointers, and other
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]1901 useful types. Each of these types contain one or more element types which
1902 may be a primitive type, or another derived type. For example, it is
1903 possible to have a two dimensional array, using an array as the element type
1904 of another array.</p>
Dan Gohman142ccc02009-01-24 15:58:40 +0000[diff] [blame]1905
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]1906<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1907<h4>
1908 <a name="t_aggregate">Aggregate Types</a>
1909</h4>
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]1910
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1911<div>
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]1912
1913<p>Aggregate Types are a subset of derived types that can contain multiple
1914 member types. <a href="#t_array">Arrays</a>,
Chris Lattner13ee7952010-08-28 04:09:24 +0000[diff] [blame]1915 <a href="#t_struct">structs</a>, and <a href="#t_vector">vectors</a> are
1916 aggregate types.</p>
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]1917
1918</div>
1919
Reid Spencer138249b2007-05-16 18:44:01 +0000[diff] [blame]1920<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1921<h4>
1922 <a name="t_array">Array Type</a>
1923</h4>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1924
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1925<div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1926
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1927<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1928<p>The array type is a very simple derived type that arranges elements
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1929 sequentially in memory. The array type requires a size (number of elements)
1930 and an underlying data type.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1931
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]1932<h5>Syntax:</h5>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1933<pre>
1934 [&lt;# elements&gt; x &lt;elementtype&gt;]
1935</pre>
1936
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1937<p>The number of elements is a constant integer value; <tt>elementtype</tt> may
1938 be any type with a size.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1939
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]1940<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1941<table class="layout">
1942 <tr class="layout">
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]1943 <td class="left"><tt>[40 x i32]</tt></td>
1944 <td class="left">Array of 40 32-bit integer values.</td>
1945 </tr>
1946 <tr class="layout">
1947 <td class="left"><tt>[41 x i32]</tt></td>
1948 <td class="left">Array of 41 32-bit integer values.</td>
1949 </tr>
1950 <tr class="layout">
1951 <td class="left"><tt>[4 x i8]</tt></td>
1952 <td class="left">Array of 4 8-bit integer values.</td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1953 </tr>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1954</table>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1955<p>Here are some examples of multidimensional arrays:</p>
1956<table class="layout">
1957 <tr class="layout">
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]1958 <td class="left"><tt>[3 x [4 x i32]]</tt></td>
1959 <td class="left">3x4 array of 32-bit integer values.</td>
1960 </tr>
1961 <tr class="layout">
1962 <td class="left"><tt>[12 x [10 x float]]</tt></td>
1963 <td class="left">12x10 array of single precision floating point values.</td>
1964 </tr>
1965 <tr class="layout">
1966 <td class="left"><tt>[2 x [3 x [4 x i16]]]</tt></td>
1967 <td class="left">2x3x4 array of 16-bit integer values.</td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1968 </tr>
1969</table>
Chris Lattnerc0ad71e2005-06-24 17:22:57 +0000[diff] [blame]1970
Dan Gohmanc74bc282009-11-09 19:01:53 +0000[diff] [blame]1971<p>There is no restriction on indexing beyond the end of the array implied by
1972 a static type (though there are restrictions on indexing beyond the bounds
1973 of an allocated object in some cases). This means that single-dimension
1974 'variable sized array' addressing can be implemented in LLVM with a zero
1975 length array type. An implementation of 'pascal style arrays' in LLVM could
1976 use the type "<tt>{ i32, [0 x float]}</tt>", for example.</p>
Chris Lattnerc0ad71e2005-06-24 17:22:57 +0000[diff] [blame]1977
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1978</div>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1979
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1980<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1981<h4>
1982 <a name="t_function">Function Type</a>
1983</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1984
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1985<div>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]1986
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1987<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1988<p>The function type can be thought of as a function signature. It consists of
1989 a return type and a list of formal parameter types. The return type of a
Chris Lattner13ee7952010-08-28 04:09:24 +0000[diff] [blame]1990 function type is a first class type or a void type.</p>
Devang Pateld6cff512008-03-10 20:49:15 +0000[diff] [blame]1991
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1992<h5>Syntax:</h5>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]1993<pre>
Nick Lewycky14d1ccc2009-09-27 07:55:32 +0000[diff] [blame]1994 &lt;returntype&gt; (&lt;parameter list&gt;)
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]1995</pre>
1996
John Criswell4c0cf7f2005-10-24 16:17:18 +0000[diff] [blame]1997<p>...where '<tt>&lt;parameter list&gt;</tt>' is a comma-separated list of type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1998 specifiers. Optionally, the parameter list may include a type <tt>...</tt>,
1999 which indicates that the function takes a variable number of arguments.
2000 Variable argument functions can access their arguments with
2001 the <a href="#int_varargs">variable argument handling intrinsic</a>
Chris Lattner47f2a832010-03-02 06:36:51 +0000[diff] [blame]2002 functions. '<tt>&lt;returntype&gt;</tt>' is any type except
Nick Lewycky93e06a52009-09-27 23:27:42 +0000[diff] [blame]2003 <a href="#t_label">label</a>.</p>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]2004
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2005<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]2006<table class="layout">
2007 <tr class="layout">
Reid Spencer58c08712006-12-31 07:18:34 +0000[diff] [blame]2008 <td class="left"><tt>i32 (i32)</tt></td>
2009 <td class="left">function taking an <tt>i32</tt>, returning an <tt>i32</tt>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]2010 </td>
Reid Spencer58c08712006-12-31 07:18:34 +0000[diff] [blame]2011 </tr><tr class="layout">
Chris Lattner47f2a832010-03-02 06:36:51 +0000[diff] [blame]2012 <td class="left"><tt>float&nbsp;(i16,&nbsp;i32&nbsp;*)&nbsp;*
Reid Spencer655dcc62006-12-31 07:20:23 +0000[diff] [blame]2013 </tt></td>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]2014 <td class="left"><a href="#t_pointer">Pointer</a> to a function that takes
Chris Lattner47f2a832010-03-02 06:36:51 +0000[diff] [blame]2015 an <tt>i16</tt> and a <a href="#t_pointer">pointer</a> to <tt>i32</tt>,
2016 returning <tt>float</tt>.
Reid Spencer58c08712006-12-31 07:18:34 +0000[diff] [blame]2017 </td>
2018 </tr><tr class="layout">
2019 <td class="left"><tt>i32 (i8*, ...)</tt></td>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]2020 <td class="left">A vararg function that takes at least one
2021 <a href="#t_pointer">pointer</a> to <tt>i8 </tt> (char in C),
2022 which returns an integer. This is the signature for <tt>printf</tt> in
Reid Spencer58c08712006-12-31 07:18:34 +0000[diff] [blame]2023 LLVM.
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]2024 </td>
Devang Patele3dfc1c2008-03-24 05:35:41 +0000[diff] [blame]2025 </tr><tr class="layout">
2026 <td class="left"><tt>{i32, i32} (i32)</tt></td>
Nick Lewycky14d1ccc2009-09-27 07:55:32 +0000[diff] [blame]2027 <td class="left">A function taking an <tt>i32</tt>, returning a
2028 <a href="#t_struct">structure</a> containing two <tt>i32</tt> values
Devang Patele3dfc1c2008-03-24 05:35:41 +0000[diff] [blame]2029 </td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]2030 </tr>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2031</table>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]2032
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2033</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2034
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2035<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2036<h4>
2037 <a name="t_struct">Structure Type</a>
2038</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2039
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2040<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2041
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2042<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2043<p>The structure type is used to represent a collection of data members together
Chris Lattnerb1ed91f2011-07-09 17:41:24 +0000[diff] [blame]2044 in memory. The elements of a structure may be any type that has a size.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2045
Jeffrey Yasskinf991bbb2010-01-11 19:19:26 +0000[diff] [blame]2046<p>Structures in memory are accessed using '<tt><a href="#i_load">load</a></tt>'
2047 and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a field
2048 with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.
2049 Structures in registers are accessed using the
2050 '<tt><a href="#i_extractvalue">extractvalue</a></tt>' and
2051 '<tt><a href="#i_insertvalue">insertvalue</a></tt>' instructions.</p>
Chris Lattnerb1ed91f2011-07-09 17:41:24 +0000[diff] [blame]2052
2053<p>Structures may optionally be "packed" structures, which indicate that the
2054 alignment of the struct is one byte, and that there is no padding between
Chris Lattner190552d2011-08-12 17:31:02 +0000[diff] [blame]2055 the elements. In non-packed structs, padding between field types is inserted
2056 as defined by the TargetData string in the module, which is required to match
Chris Lattner7bd0ea32011-10-11 23:02:17 +0000[diff] [blame]2057 what the underlying code generator expects.</p>
Chris Lattnerb1ed91f2011-07-09 17:41:24 +0000[diff] [blame]2058
Chris Lattner190552d2011-08-12 17:31:02 +0000[diff] [blame]2059<p>Structures can either be "literal" or "identified". A literal structure is
2060 defined inline with other types (e.g. <tt>{i32, i32}*</tt>) whereas identified
2061 types are always defined at the top level with a name. Literal types are
2062 uniqued by their contents and can never be recursive or opaque since there is
Chris Lattner32531732011-08-12 18:12:40 +0000[diff] [blame]2063 no way to write one. Identified types can be recursive, can be opaqued, and are
Chris Lattner190552d2011-08-12 17:31:02 +0000[diff] [blame]2064 never uniqued.
Chris Lattnerb1ed91f2011-07-09 17:41:24 +0000[diff] [blame]2065</p>
2066
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2067<h5>Syntax:</h5>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]2068<pre>
Chris Lattner190552d2011-08-12 17:31:02 +0000[diff] [blame]2069 %T1 = type { &lt;type list&gt; } <i>; Identified normal struct type</i>
2070 %T2 = type &lt;{ &lt;type list&gt; }&gt; <i>; Identified packed struct type</i>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]2071</pre>
Chris Lattnerb1ed91f2011-07-09 17:41:24 +0000[diff] [blame]2072
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2073<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]2074<table class="layout">
2075 <tr class="layout">
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]2076 <td class="left"><tt>{ i32, i32, i32 }</tt></td>
2077 <td class="left">A triple of three <tt>i32</tt> values</td>
Chris Lattnerb1ed91f2011-07-09 17:41:24 +0000[diff] [blame]2078 </tr>
2079 <tr class="layout">
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]2080 <td class="left"><tt>{&nbsp;float,&nbsp;i32&nbsp;(i32)&nbsp;*&nbsp;}</tt></td>
2081 <td class="left">A pair, where the first element is a <tt>float</tt> and the
2082 second element is a <a href="#t_pointer">pointer</a> to a
2083 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
2084 an <tt>i32</tt>.</td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]2085 </tr>
Chris Lattnerb1ed91f2011-07-09 17:41:24 +0000[diff] [blame]2086 <tr class="layout">
2087 <td class="left"><tt>&lt;{ i8, i32 }&gt;</tt></td>
2088 <td class="left">A packed struct known to be 5 bytes in size.</td>
2089 </tr>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2090</table>
Dan Gohman142ccc02009-01-24 15:58:40 +0000[diff] [blame]2091
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2092</div>
Chris Lattnerb1ed91f2011-07-09 17:41:24 +0000[diff] [blame]2093
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2094<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2095<h4>
Chris Lattner2a843822011-07-23 19:59:08 +0000[diff] [blame]2096 <a name="t_opaque">Opaque Structure Types</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2097</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2098
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2099<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2100
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]2101<h5>Overview:</h5>
Chris Lattner2a843822011-07-23 19:59:08 +0000[diff] [blame]2102<p>Opaque structure types are used to represent named structure types that do
2103 not have a body specified. This corresponds (for example) to the C notion of
2104 a forward declared structure.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2105
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]2106<h5>Syntax:</h5>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]2107<pre>
Chris Lattnerb1ed91f2011-07-09 17:41:24 +0000[diff] [blame]2108 %X = type opaque
2109 %52 = type opaque
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]2110</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2111
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]2112<h5>Examples:</h5>
2113<table class="layout">
2114 <tr class="layout">
Chris Lattnerb1ed91f2011-07-09 17:41:24 +0000[diff] [blame]2115 <td class="left"><tt>opaque</tt></td>
2116 <td class="left">An opaque type.</td>
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]2117 </tr>
2118</table>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2119
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]2120</div>
2121
Chris Lattnerb1ed91f2011-07-09 17:41:24 +0000[diff] [blame]2122
2123
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]2124<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2125<h4>
2126 <a name="t_pointer">Pointer Type</a>
2127</h4>
Chris Lattner4a67c912009-02-08 19:53:29 +0000[diff] [blame]2128
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2129<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2130
2131<h5>Overview:</h5>
Dan Gohman88481112010-02-25 16:50:07 +0000[diff] [blame]2132<p>The pointer type is used to specify memory locations.
2133 Pointers are commonly used to reference objects in memory.</p>
2134
2135<p>Pointer types may have an optional address space attribute defining the
2136 numbered address space where the pointed-to object resides. The default
2137 address space is number zero. The semantics of non-zero address
2138 spaces are target-specific.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2139
2140<p>Note that LLVM does not permit pointers to void (<tt>void*</tt>) nor does it
2141 permit pointers to labels (<tt>label*</tt>). Use <tt>i8*</tt> instead.</p>
Chris Lattner4a67c912009-02-08 19:53:29 +0000[diff] [blame]2142
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]2143<h5>Syntax:</h5>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]2144<pre>
2145 &lt;type&gt; *
2146</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2147
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]2148<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]2149<table class="layout">
2150 <tr class="layout">
Dan Gohman623806e2009-01-04 23:44:43 +0000[diff] [blame]2151 <td class="left"><tt>[4 x i32]*</tt></td>
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]2152 <td class="left">A <a href="#t_pointer">pointer</a> to <a
2153 href="#t_array">array</a> of four <tt>i32</tt> values.</td>
2154 </tr>
2155 <tr class="layout">
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]2156 <td class="left"><tt>i32 (i32*) *</tt></td>
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]2157 <td class="left"> A <a href="#t_pointer">pointer</a> to a <a
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2158 href="#t_function">function</a> that takes an <tt>i32*</tt>, returning an
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]2159 <tt>i32</tt>.</td>
2160 </tr>
2161 <tr class="layout">
2162 <td class="left"><tt>i32 addrspace(5)*</tt></td>
2163 <td class="left">A <a href="#t_pointer">pointer</a> to an <tt>i32</tt> value
2164 that resides in address space #5.</td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]2165 </tr>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2166</table>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2167
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2168</div>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]2169
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]2170<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2171<h4>
2172 <a name="t_vector">Vector Type</a>
2173</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2174
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2175<div>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]2176
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]2177<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2178<p>A vector type is a simple derived type that represents a vector of elements.
2179 Vector types are used when multiple primitive data are operated in parallel
2180 using a single instruction (SIMD). A vector type requires a size (number of
Duncan Sands31c0e0e2009-11-27 13:38:03 +0000[diff] [blame]2181 elements) and an underlying primitive data type. Vector types are considered
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2182 <a href="#t_firstclass">first class</a>.</p>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]2183
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]2184<h5>Syntax:</h5>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]2185<pre>
2186 &lt; &lt;# elements&gt; x &lt;elementtype&gt; &gt;
2187</pre>
2188
Chris Lattnerf11031a2010-10-10 18:20:35 +0000[diff] [blame]2189<p>The number of elements is a constant integer value larger than 0; elementtype
2190 may be any integer or floating point type. Vectors of size zero are not
2191 allowed, and pointers are not allowed as the element type.</p>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]2192
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]2193<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]2194<table class="layout">
2195 <tr class="layout">
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]2196 <td class="left"><tt>&lt;4 x i32&gt;</tt></td>
2197 <td class="left">Vector of 4 32-bit integer values.</td>
2198 </tr>
2199 <tr class="layout">
2200 <td class="left"><tt>&lt;8 x float&gt;</tt></td>
2201 <td class="left">Vector of 8 32-bit floating-point values.</td>
2202 </tr>
2203 <tr class="layout">
2204 <td class="left"><tt>&lt;2 x i64&gt;</tt></td>
2205 <td class="left">Vector of 2 64-bit integer values.</td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]2206 </tr>
2207</table>
Dan Gohman142ccc02009-01-24 15:58:40 +0000[diff] [blame]2208
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2209</div>
2210
Bill Wendlingae8b5ea2011-07-31 06:47:33 +0000[diff] [blame]2211</div>
2212
NAKAMURA Takumia35cdd62011-10-31 13:04:26 +0000[diff] [blame]2213</div>
2214
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2215<!-- *********************************************************************** -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2216<h2><a name="constants">Constants</a></h2>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2217<!-- *********************************************************************** -->
2218
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2219<div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2220
2221<p>LLVM has several different basic types of constants. This section describes
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2222 them all and their syntax.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2223
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2224<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2225<h3>
2226 <a name="simpleconstants">Simple Constants</a>
2227</h3>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2228
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2229<div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2230
2231<dl>
2232 <dt><b>Boolean constants</b></dt>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2233 <dd>The two strings '<tt>true</tt>' and '<tt>false</tt>' are both valid
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]2234 constants of the <tt><a href="#t_integer">i1</a></tt> type.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2235
2236 <dt><b>Integer constants</b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2237 <dd>Standard integers (such as '4') are constants of
2238 the <a href="#t_integer">integer</a> type. Negative numbers may be used
2239 with integer types.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2240
2241 <dt><b>Floating point constants</b></dt>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2242 <dd>Floating point constants use standard decimal notation (e.g. 123.421),
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2243 exponential notation (e.g. 1.23421e+2), or a more precise hexadecimal
2244 notation (see below). The assembler requires the exact decimal value of a
2245 floating-point constant. For example, the assembler accepts 1.25 but
2246 rejects 1.3 because 1.3 is a repeating decimal in binary. Floating point
2247 constants must have a <a href="#t_floating">floating point</a> type. </dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2248
2249 <dt><b>Null pointer constants</b></dt>
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]2250 <dd>The identifier '<tt>null</tt>' is recognized as a null pointer constant
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2251 and must be of <a href="#t_pointer">pointer type</a>.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2252</dl>
2253
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2254<p>The one non-intuitive notation for constants is the hexadecimal form of
2255 floating point constants. For example, the form '<tt>double
2256 0x432ff973cafa8000</tt>' is equivalent to (but harder to read than)
2257 '<tt>double 4.5e+15</tt>'. The only time hexadecimal floating point
2258 constants are required (and the only time that they are generated by the
2259 disassembler) is when a floating point constant must be emitted but it cannot
2260 be represented as a decimal floating point number in a reasonable number of
2261 digits. For example, NaN's, infinities, and other special values are
2262 represented in their IEEE hexadecimal format so that assembly and disassembly
2263 do not cause any bits to change in the constants.</p>
2264
Dale Johannesencd4a3012009-02-11 22:14:51 +0000[diff] [blame]2265<p>When using the hexadecimal form, constants of types float and double are
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2266 represented using the 16-digit form shown above (which matches the IEEE754
2267 representation for double); float values must, however, be exactly
2268 representable as IEE754 single precision. Hexadecimal format is always used
2269 for long double, and there are three forms of long double. The 80-bit format
2270 used by x86 is represented as <tt>0xK</tt> followed by 20 hexadecimal digits.
2271 The 128-bit format used by PowerPC (two adjacent doubles) is represented
2272 by <tt>0xM</tt> followed by 32 hexadecimal digits. The IEEE 128-bit format
2273 is represented by <tt>0xL</tt> followed by 32 hexadecimal digits; no
2274 currently supported target uses this format. Long doubles will only work if
2275 they match the long double format on your target. All hexadecimal formats
2276 are big-endian (sign bit at the left).</p>
2277
Dale Johannesen33e5c352010-10-01 00:48:59 +0000[diff] [blame]2278<p>There are no constants of type x86mmx.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2279</div>
2280
2281<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2282<h3>
Bill Wendling972b7202009-07-20 02:32:41 +0000[diff] [blame]2283<a name="aggregateconstants"></a> <!-- old anchor -->
2284<a name="complexconstants">Complex Constants</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2285</h3>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2286
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2287<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2288
Chris Lattner361bfcd2009-02-28 18:32:25 +0000[diff] [blame]2289<p>Complex constants are a (potentially recursive) combination of simple
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2290 constants and smaller complex constants.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2291
2292<dl>
2293 <dt><b>Structure constants</b></dt>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2294 <dd>Structure constants are represented with notation similar to structure
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2295 type definitions (a comma separated list of elements, surrounded by braces
2296 (<tt>{}</tt>)). For example: "<tt>{ i32 4, float 17.0, i32* @G }</tt>",
2297 where "<tt>@G</tt>" is declared as "<tt>@G = external global i32</tt>".
2298 Structure constants must have <a href="#t_struct">structure type</a>, and
2299 the number and types of elements must match those specified by the
2300 type.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2301
2302 <dt><b>Array constants</b></dt>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2303 <dd>Array constants are represented with notation similar to array type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2304 definitions (a comma separated list of elements, surrounded by square
2305 brackets (<tt>[]</tt>)). For example: "<tt>[ i32 42, i32 11, i32 74
2306 ]</tt>". Array constants must have <a href="#t_array">array type</a>, and
2307 the number and types of elements must match those specified by the
2308 type.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2309
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]2310 <dt><b>Vector constants</b></dt>
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]2311 <dd>Vector constants are represented with notation similar to vector type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2312 definitions (a comma separated list of elements, surrounded by
2313 less-than/greater-than's (<tt>&lt;&gt;</tt>)). For example: "<tt>&lt; i32
2314 42, i32 11, i32 74, i32 100 &gt;</tt>". Vector constants must
2315 have <a href="#t_vector">vector type</a>, and the number and types of
2316 elements must match those specified by the type.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2317
2318 <dt><b>Zero initialization</b></dt>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2319 <dd>The string '<tt>zeroinitializer</tt>' can be used to zero initialize a
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]2320 value to zero of <em>any</em> type, including scalar and
2321 <a href="#t_aggregate">aggregate</a> types.
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2322 This is often used to avoid having to print large zero initializers
2323 (e.g. for large arrays) and is always exactly equivalent to using explicit
2324 zero initializers.</dd>
Nick Lewycky49f89192009-04-04 07:22:01 +0000[diff] [blame]2325
2326 <dt><b>Metadata node</b></dt>
Nick Lewycky8e2c4f42009-05-30 16:08:30 +0000[diff] [blame]2327 <dd>A metadata node is a structure-like constant with
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2328 <a href="#t_metadata">metadata type</a>. For example: "<tt>metadata !{
2329 i32 0, metadata !"test" }</tt>". Unlike other constants that are meant to
2330 be interpreted as part of the instruction stream, metadata is a place to
2331 attach additional information such as debug info.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2332</dl>
2333
2334</div>
2335
2336<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2337<h3>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2338 <a name="globalconstants">Global Variable and Function Addresses</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2339</h3>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2340
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2341<div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2342
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2343<p>The addresses of <a href="#globalvars">global variables</a>
2344 and <a href="#functionstructure">functions</a> are always implicitly valid
2345 (link-time) constants. These constants are explicitly referenced when
2346 the <a href="#identifiers">identifier for the global</a> is used and always
2347 have <a href="#t_pointer">pointer</a> type. For example, the following is a
2348 legal LLVM file:</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2349
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2350<pre class="doc_code">
Chris Lattner00538a12007-06-06 18:28:13 +0000[diff] [blame]2351@X = global i32 17
2352@Y = global i32 42
2353@Z = global [2 x i32*] [ i32* @X, i32* @Y ]
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2354</pre>
2355
2356</div>
2357
2358<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2359<h3>
2360 <a name="undefvalues">Undefined Values</a>
2361</h3>
2362
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2363<div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2364
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2365<p>The string '<tt>undef</tt>' can be used anywhere a constant is expected, and
Benjamin Kramer0f420382009-10-12 14:46:08 +0000[diff] [blame]2366 indicates that the user of the value may receive an unspecified bit-pattern.
Bill Wendling6bbe0912010-10-27 01:07:41 +0000[diff] [blame]2367 Undefined values may be of any type (other than '<tt>label</tt>'
2368 or '<tt>void</tt>') and be used anywhere a constant is permitted.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2369
Chris Lattner92ada5d2009-09-11 01:49:31 +0000[diff] [blame]2370<p>Undefined values are useful because they indicate to the compiler that the
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2371 program is well defined no matter what value is used. This gives the
2372 compiler more freedom to optimize. Here are some examples of (potentially
2373 surprising) transformations that are valid (in pseudo IR):</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2374
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2375
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2376<pre class="doc_code">
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2377 %A = add %X, undef
2378 %B = sub %X, undef
2379 %C = xor %X, undef
2380Safe:
2381 %A = undef
2382 %B = undef
2383 %C = undef
2384</pre>
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2385
2386<p>This is safe because all of the output bits are affected by the undef bits.
Bill Wendling6bbe0912010-10-27 01:07:41 +0000[diff] [blame]2387 Any output bit can have a zero or one depending on the input bits.</p>
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2388
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2389<pre class="doc_code">
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2390 %A = or %X, undef
2391 %B = and %X, undef
2392Safe:
2393 %A = -1
2394 %B = 0
2395Unsafe:
2396 %A = undef
2397 %B = undef
2398</pre>
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2399
2400<p>These logical operations have bits that are not always affected by the input.
Bill Wendling6bbe0912010-10-27 01:07:41 +0000[diff] [blame]2401 For example, if <tt>%X</tt> has a zero bit, then the output of the
2402 '<tt>and</tt>' operation will always be a zero for that bit, no matter what
2403 the corresponding bit from the '<tt>undef</tt>' is. As such, it is unsafe to
2404 optimize or assume that the result of the '<tt>and</tt>' is '<tt>undef</tt>'.
2405 However, it is safe to assume that all bits of the '<tt>undef</tt>' could be
2406 0, and optimize the '<tt>and</tt>' to 0. Likewise, it is safe to assume that
2407 all the bits of the '<tt>undef</tt>' operand to the '<tt>or</tt>' could be
2408 set, allowing the '<tt>or</tt>' to be folded to -1.</p>
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2409
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2410<pre class="doc_code">
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2411 %A = select undef, %X, %Y
2412 %B = select undef, 42, %Y
2413 %C = select %X, %Y, undef
2414Safe:
2415 %A = %X (or %Y)
2416 %B = 42 (or %Y)
2417 %C = %Y
2418Unsafe:
2419 %A = undef
2420 %B = undef
2421 %C = undef
2422</pre>
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2423
Bill Wendling6bbe0912010-10-27 01:07:41 +0000[diff] [blame]2424<p>This set of examples shows that undefined '<tt>select</tt>' (and conditional
2425 branch) conditions can go <em>either way</em>, but they have to come from one
2426 of the two operands. In the <tt>%A</tt> example, if <tt>%X</tt> and
2427 <tt>%Y</tt> were both known to have a clear low bit, then <tt>%A</tt> would
2428 have to have a cleared low bit. However, in the <tt>%C</tt> example, the
2429 optimizer is allowed to assume that the '<tt>undef</tt>' operand could be the
2430 same as <tt>%Y</tt>, allowing the whole '<tt>select</tt>' to be
2431 eliminated.</p>
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2432
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2433<pre class="doc_code">
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2434 %A = xor undef, undef
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]2435
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2436 %B = undef
2437 %C = xor %B, %B
2438
2439 %D = undef
2440 %E = icmp lt %D, 4
2441 %F = icmp gte %D, 4
2442
2443Safe:
2444 %A = undef
2445 %B = undef
2446 %C = undef
2447 %D = undef
2448 %E = undef
2449 %F = undef
2450</pre>
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2451
Bill Wendling6bbe0912010-10-27 01:07:41 +0000[diff] [blame]2452<p>This example points out that two '<tt>undef</tt>' operands are not
2453 necessarily the same. This can be surprising to people (and also matches C
2454 semantics) where they assume that "<tt>X^X</tt>" is always zero, even
2455 if <tt>X</tt> is undefined. This isn't true for a number of reasons, but the
2456 short answer is that an '<tt>undef</tt>' "variable" can arbitrarily change
2457 its value over its "live range". This is true because the variable doesn't
2458 actually <em>have a live range</em>. Instead, the value is logically read
2459 from arbitrary registers that happen to be around when needed, so the value
2460 is not necessarily consistent over time. In fact, <tt>%A</tt> and <tt>%C</tt>
2461 need to have the same semantics or the core LLVM "replace all uses with"
2462 concept would not hold.</p>
Chris Lattnera34a7182009-09-07 23:33:52 +0000[diff] [blame]2463
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2464<pre class="doc_code">
Chris Lattnera34a7182009-09-07 23:33:52 +0000[diff] [blame]2465 %A = fdiv undef, %X
2466 %B = fdiv %X, undef
2467Safe:
2468 %A = undef
2469b: unreachable
2470</pre>
Chris Lattnera34a7182009-09-07 23:33:52 +0000[diff] [blame]2471
2472<p>These examples show the crucial difference between an <em>undefined
Bill Wendling6bbe0912010-10-27 01:07:41 +0000[diff] [blame]2473 value</em> and <em>undefined behavior</em>. An undefined value (like
2474 '<tt>undef</tt>') is allowed to have an arbitrary bit-pattern. This means that
2475 the <tt>%A</tt> operation can be constant folded to '<tt>undef</tt>', because
2476 the '<tt>undef</tt>' could be an SNaN, and <tt>fdiv</tt> is not (currently)
2477 defined on SNaN's. However, in the second example, we can make a more
2478 aggressive assumption: because the <tt>undef</tt> is allowed to be an
2479 arbitrary value, we are allowed to assume that it could be zero. Since a
2480 divide by zero has <em>undefined behavior</em>, we are allowed to assume that
2481 the operation does not execute at all. This allows us to delete the divide and
2482 all code after it. Because the undefined operation "can't happen", the
2483 optimizer can assume that it occurs in dead code.</p>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]2484
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2485<pre class="doc_code">
Chris Lattnera34a7182009-09-07 23:33:52 +0000[diff] [blame]2486a: store undef -> %X
2487b: store %X -> undef
2488Safe:
2489a: &lt;deleted&gt;
2490b: unreachable
2491</pre>
Chris Lattnera34a7182009-09-07 23:33:52 +0000[diff] [blame]2492
Bill Wendling6bbe0912010-10-27 01:07:41 +0000[diff] [blame]2493<p>These examples reiterate the <tt>fdiv</tt> example: a store <em>of</em> an
2494 undefined value can be assumed to not have any effect; we can assume that the
2495 value is overwritten with bits that happen to match what was already there.
2496 However, a store <em>to</em> an undefined location could clobber arbitrary
2497 memory, therefore, it has undefined behavior.</p>
Chris Lattnera34a7182009-09-07 23:33:52 +0000[diff] [blame]2498
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2499</div>
2500
2501<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2502<h3>
2503 <a name="trapvalues">Trap Values</a>
2504</h3>
2505
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2506<div>
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]2507
Dan Gohmanb2a709b2010-04-26 20:21:21 +0000[diff] [blame]2508<p>Trap values are similar to <a href="#undefvalues">undef values</a>, however
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]2509 instead of representing an unspecified bit pattern, they represent the
2510 fact that an instruction or constant expression which cannot evoke side
2511 effects has nevertheless detected a condition which results in undefined
Dan Gohmanb2a709b2010-04-26 20:21:21 +0000[diff] [blame]2512 behavior.</p>
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]2513
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2514<p>There is currently no way of representing a trap value in the IR; they
Dan Gohmanac355aa2010-05-03 14:51:43 +0000[diff] [blame]2515 only exist when produced by operations such as
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2516 <a href="#i_add"><tt>add</tt></a> with the <tt>nsw</tt> flag.</p>
Dan Gohmanb8b85c12010-04-26 23:36:52 +0000[diff] [blame]2517
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2518<p>Trap value behavior is defined in terms of value <i>dependence</i>:</p>
Dan Gohmanb8b85c12010-04-26 23:36:52 +0000[diff] [blame]2519
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2520<ul>
2521<li>Values other than <a href="#i_phi"><tt>phi</tt></a> nodes depend on
2522 their operands.</li>
2523
2524<li><a href="#i_phi"><tt>Phi</tt></a> nodes depend on the operand corresponding
2525 to their dynamic predecessor basic block.</li>
2526
2527<li>Function arguments depend on the corresponding actual argument values in
2528 the dynamic callers of their functions.</li>
2529
2530<li><a href="#i_call"><tt>Call</tt></a> instructions depend on the
2531 <a href="#i_ret"><tt>ret</tt></a> instructions that dynamically transfer
2532 control back to them.</li>
2533
Dan Gohman7292a752010-05-03 14:55:22 +0000[diff] [blame]2534<li><a href="#i_invoke"><tt>Invoke</tt></a> instructions depend on the
2535 <a href="#i_ret"><tt>ret</tt></a>, <a href="#i_unwind"><tt>unwind</tt></a>,
2536 or exception-throwing call instructions that dynamically transfer control
2537 back to them.</li>
2538
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2539<li>Non-volatile loads and stores depend on the most recent stores to all of the
2540 referenced memory addresses, following the order in the IR
2541 (including loads and stores implied by intrinsics such as
2542 <a href="#int_memcpy"><tt>@llvm.memcpy</tt></a>.)</li>
2543
Dan Gohman3513ea52010-05-03 14:59:34 +0000[diff] [blame]2544<!-- TODO: In the case of multiple threads, this only applies if the store
2545 "happens-before" the load or store. -->
Dan Gohmanb8b85c12010-04-26 23:36:52 +0000[diff] [blame]2546
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2547<!-- TODO: floating-point exception state -->
Dan Gohmanb8b85c12010-04-26 23:36:52 +0000[diff] [blame]2548
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2549<li>An instruction with externally visible side effects depends on the most
2550 recent preceding instruction with externally visible side effects, following
Dan Gohman6c858db2010-07-06 15:26:33 +0000[diff] [blame]2551 the order in the IR. (This includes
2552 <a href="#volatile">volatile operations</a>.)</li>
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]2553
Dan Gohman7292a752010-05-03 14:55:22 +0000[diff] [blame]2554<li>An instruction <i>control-depends</i> on a
2555 <a href="#terminators">terminator instruction</a>
2556 if the terminator instruction has multiple successors and the instruction
2557 is always executed when control transfers to one of the successors, and
Chris Lattner0ab5e2c2011-04-15 05:18:47 +0000[diff] [blame]2558 may not be executed when control is transferred to another.</li>
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2559
Dan Gohmanc8454ee2011-04-12 23:05:59 +0000[diff] [blame]2560<li>Additionally, an instruction also <i>control-depends</i> on a terminator
2561 instruction if the set of instructions it otherwise depends on would be
Chris Lattner0ab5e2c2011-04-15 05:18:47 +0000[diff] [blame]2562 different if the terminator had transferred control to a different
Dan Gohmanc8454ee2011-04-12 23:05:59 +0000[diff] [blame]2563 successor.</li>
2564
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2565<li>Dependence is transitive.</li>
2566
2567</ul>
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2568
2569<p>Whenever a trap value is generated, all values which depend on it evaluate
Lang Hames91fc0902011-10-13 23:04:49 +0000[diff] [blame]2570 to trap. If they have side effects, they evoke their side effects as if each
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2571 operand with a trap value were undef. If they have externally-visible side
2572 effects, the behavior is undefined.</p>
2573
2574<p>Here are some examples:</p>
Dan Gohman48a25882010-04-26 20:54:53 +0000[diff] [blame]2575
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2576<pre class="doc_code">
Dan Gohmanb8b85c12010-04-26 23:36:52 +0000[diff] [blame]2577entry:
2578 %trap = sub nuw i32 0, 1 ; Results in a trap value.
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2579 %still_trap = and i32 %trap, 0 ; Whereas (and i32 undef, 0) would return 0.
2580 %trap_yet_again = getelementptr i32* @h, i32 %still_trap
2581 store i32 0, i32* %trap_yet_again ; undefined behavior
2582
2583 store i32 %trap, i32* @g ; Trap value conceptually stored to memory.
2584 %trap2 = load i32* @g ; Returns a trap value, not just undef.
2585
Chris Lattnerbc639292011-11-27 06:56:53 +0000[diff] [blame]2586 store volatile i32 %trap, i32* @g ; External observation; undefined behavior.
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2587
2588 %narrowaddr = bitcast i32* @g to i16*
2589 %wideaddr = bitcast i32* @g to i64*
Nick Lewycky9c876bf2011-05-16 19:29:30 +0000[diff] [blame]2590 %trap3 = load i16* %narrowaddr ; Returns a trap value.
2591 %trap4 = load i64* %wideaddr ; Returns a trap value.
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2592
Nick Lewycky9c876bf2011-05-16 19:29:30 +0000[diff] [blame]2593 %cmp = icmp slt i32 %trap, 0 ; Returns a trap value.
2594 br i1 %cmp, label %true, label %end ; Branch to either destination.
Dan Gohmanb8b85c12010-04-26 23:36:52 +0000[diff] [blame]2595
2596true:
Chris Lattnerbc639292011-11-27 06:56:53 +0000[diff] [blame]2597 store volatile i32 0, i32* @g ; This is control-dependent on %cmp, so
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2598 ; it has undefined behavior.
Dan Gohmanb8b85c12010-04-26 23:36:52 +0000[diff] [blame]2599 br label %end
2600
2601end:
2602 %p = phi i32 [ 0, %entry ], [ 1, %true ]
2603 ; Both edges into this PHI are
2604 ; control-dependent on %cmp, so this
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2605 ; always results in a trap value.
Dan Gohmanb8b85c12010-04-26 23:36:52 +0000[diff] [blame]2606
Chris Lattnerbc639292011-11-27 06:56:53 +0000[diff] [blame]2607 store volatile i32 0, i32* @g ; This would depend on the store in %true
Dan Gohmanc8454ee2011-04-12 23:05:59 +0000[diff] [blame]2608 ; if %cmp is true, or the store in %entry
2609 ; otherwise, so this is undefined behavior.
2610
Nick Lewycky9c876bf2011-05-16 19:29:30 +0000[diff] [blame]2611 br i1 %cmp, label %second_true, label %second_end
Dan Gohmanc8454ee2011-04-12 23:05:59 +0000[diff] [blame]2612 ; The same branch again, but this time the
2613 ; true block doesn't have side effects.
2614
2615second_true:
2616 ; No side effects!
Nick Lewycky9c876bf2011-05-16 19:29:30 +0000[diff] [blame]2617 ret void
Dan Gohmanc8454ee2011-04-12 23:05:59 +0000[diff] [blame]2618
2619second_end:
Chris Lattnerbc639292011-11-27 06:56:53 +0000[diff] [blame]2620 store volatile i32 0, i32* @g ; This time, the instruction always depends
Dan Gohmanc8454ee2011-04-12 23:05:59 +0000[diff] [blame]2621 ; on the store in %end. Also, it is
2622 ; control-equivalent to %end, so this is
Nick Lewycky9c876bf2011-05-16 19:29:30 +0000[diff] [blame]2623 ; well-defined (again, ignoring earlier
Dan Gohmanb8b85c12010-04-26 23:36:52 +0000[diff] [blame]2624 ; undefined behavior in this example).
Dan Gohmanb8b85c12010-04-26 23:36:52 +0000[diff] [blame]2625</pre>
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]2626
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]2627</div>
2628
2629<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2630<h3>
2631 <a name="blockaddress">Addresses of Basic Blocks</a>
2632</h3>
2633
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2634<div>
Chris Lattnere4801f72009-10-27 21:01:34 +0000[diff] [blame]2635
Chris Lattneraa99c942009-11-01 01:27:45 +0000[diff] [blame]2636<p><b><tt>blockaddress(@function, %block)</tt></b></p>
Chris Lattnere4801f72009-10-27 21:01:34 +0000[diff] [blame]2637
2638<p>The '<tt>blockaddress</tt>' constant computes the address of the specified
Chris Lattner5c5f0ac2009-10-27 21:49:40 +0000[diff] [blame]2639 basic block in the specified function, and always has an i8* type. Taking
Chris Lattneraa99c942009-11-01 01:27:45 +0000[diff] [blame]2640 the address of the entry block is illegal.</p>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]2641
Chris Lattnere4801f72009-10-27 21:01:34 +0000[diff] [blame]2642<p>This value only has defined behavior when used as an operand to the
Bill Wendling6bbe0912010-10-27 01:07:41 +0000[diff] [blame]2643 '<a href="#i_indirectbr"><tt>indirectbr</tt></a>' instruction, or for
2644 comparisons against null. Pointer equality tests between labels addresses
2645 results in undefined behavior &mdash; though, again, comparison against null
2646 is ok, and no label is equal to the null pointer. This may be passed around
2647 as an opaque pointer sized value as long as the bits are not inspected. This
2648 allows <tt>ptrtoint</tt> and arithmetic to be performed on these values so
2649 long as the original value is reconstituted before the <tt>indirectbr</tt>
2650 instruction.</p>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]2651
Bill Wendling6bbe0912010-10-27 01:07:41 +0000[diff] [blame]2652<p>Finally, some targets may provide defined semantics when using the value as
2653 the operand to an inline assembly, but that is target specific.</p>
Chris Lattnere4801f72009-10-27 21:01:34 +0000[diff] [blame]2654
2655</div>
2656
2657
2658<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2659<h3>
2660 <a name="constantexprs">Constant Expressions</a>
2661</h3>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2662
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2663<div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2664
2665<p>Constant expressions are used to allow expressions involving other constants
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2666 to be used as constants. Constant expressions may be of
2667 any <a href="#t_firstclass">first class</a> type and may involve any LLVM
2668 operation that does not have side effects (e.g. load and call are not
Bill Wendling6bbe0912010-10-27 01:07:41 +0000[diff] [blame]2669 supported). The following is the syntax for constant expressions:</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2670
2671<dl>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2672 <dt><b><tt>trunc (CST to TYPE)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2673 <dd>Truncate a constant to another type. The bit size of CST must be larger
2674 than the bit size of TYPE. Both types must be integers.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2675
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2676 <dt><b><tt>zext (CST to TYPE)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2677 <dd>Zero extend a constant to another type. The bit size of CST must be
Duncan Sandsa522e562010-07-13 12:06:14 +0000[diff] [blame]2678 smaller than the bit size of TYPE. Both types must be integers.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2679
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2680 <dt><b><tt>sext (CST to TYPE)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2681 <dd>Sign extend a constant to another type. The bit size of CST must be
Duncan Sandsa522e562010-07-13 12:06:14 +0000[diff] [blame]2682 smaller than the bit size of TYPE. Both types must be integers.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2683
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2684 <dt><b><tt>fptrunc (CST to TYPE)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2685 <dd>Truncate a floating point constant to another floating point type. The
2686 size of CST must be larger than the size of TYPE. Both types must be
2687 floating point.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2688
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2689 <dt><b><tt>fpext (CST to TYPE)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2690 <dd>Floating point extend a constant to another type. The size of CST must be
2691 smaller or equal to the size of TYPE. Both types must be floating
2692 point.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2693
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2694 <dt><b><tt>fptoui (CST to TYPE)</tt></b></dt>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2695 <dd>Convert a floating point constant to the corresponding unsigned integer
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2696 constant. TYPE must be a scalar or vector integer type. CST must be of
2697 scalar or vector floating point type. Both CST and TYPE must be scalars,
2698 or vectors of the same number of elements. If the value won't fit in the
2699 integer type, the results are undefined.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2700
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2701 <dt><b><tt>fptosi (CST to TYPE)</tt></b></dt>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2702 <dd>Convert a floating point constant to the corresponding signed integer
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2703 constant. TYPE must be a scalar or vector integer type. CST must be of
2704 scalar or vector floating point type. Both CST and TYPE must be scalars,
2705 or vectors of the same number of elements. If the value won't fit in the
2706 integer type, the results are undefined.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2707
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2708 <dt><b><tt>uitofp (CST to TYPE)</tt></b></dt>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2709 <dd>Convert an unsigned integer constant to the corresponding floating point
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2710 constant. TYPE must be a scalar or vector floating point type. CST must be
2711 of scalar or vector integer type. Both CST and TYPE must be scalars, or
2712 vectors of the same number of elements. If the value won't fit in the
2713 floating point type, the results are undefined.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2714
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2715 <dt><b><tt>sitofp (CST to TYPE)</tt></b></dt>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2716 <dd>Convert a signed integer constant to the corresponding floating point
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2717 constant. TYPE must be a scalar or vector floating point type. CST must be
2718 of scalar or vector integer type. Both CST and TYPE must be scalars, or
2719 vectors of the same number of elements. If the value won't fit in the
2720 floating point type, the results are undefined.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2721
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2722 <dt><b><tt>ptrtoint (CST to TYPE)</tt></b></dt>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]2723 <dd>Convert a pointer typed constant to the corresponding integer constant
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2724 <tt>TYPE</tt> must be an integer type. <tt>CST</tt> must be of pointer
2725 type. The <tt>CST</tt> value is zero extended, truncated, or unchanged to
2726 make it fit in <tt>TYPE</tt>.</dd>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]2727
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2728 <dt><b><tt>inttoptr (CST to TYPE)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2729 <dd>Convert a integer constant to a pointer constant. TYPE must be a pointer
2730 type. CST must be of integer type. The CST value is zero extended,
2731 truncated, or unchanged to make it fit in a pointer size. This one is
2732 <i>really</i> dangerous!</dd>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]2733
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2734 <dt><b><tt>bitcast (CST to TYPE)</tt></b></dt>
Chris Lattner789dee32009-02-28 18:27:03 +0000[diff] [blame]2735 <dd>Convert a constant, CST, to another TYPE. The constraints of the operands
2736 are the same as those for the <a href="#i_bitcast">bitcast
2737 instruction</a>.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2738
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2739 <dt><b><tt>getelementptr (CSTPTR, IDX0, IDX1, ...)</tt></b></dt>
2740 <dt><b><tt>getelementptr inbounds (CSTPTR, IDX0, IDX1, ...)</tt></b></dt>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2741 <dd>Perform the <a href="#i_getelementptr">getelementptr operation</a> on
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2742 constants. As with the <a href="#i_getelementptr">getelementptr</a>
2743 instruction, the index list may have zero or more indexes, which are
2744 required to make sense for the type of "CSTPTR".</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2745
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2746 <dt><b><tt>select (COND, VAL1, VAL2)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2747 <dd>Perform the <a href="#i_select">select operation</a> on constants.</dd>
Reid Spencer9965ee72006-12-04 19:23:19 +0000[diff] [blame]2748
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2749 <dt><b><tt>icmp COND (VAL1, VAL2)</tt></b></dt>
Reid Spencer9965ee72006-12-04 19:23:19 +0000[diff] [blame]2750 <dd>Performs the <a href="#i_icmp">icmp operation</a> on constants.</dd>
2751
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2752 <dt><b><tt>fcmp COND (VAL1, VAL2)</tt></b></dt>
Reid Spencer9965ee72006-12-04 19:23:19 +0000[diff] [blame]2753 <dd>Performs the <a href="#i_fcmp">fcmp operation</a> on constants.</dd>
Robert Bocchino7e97a6d2006-01-10 19:31:34 +0000[diff] [blame]2754
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2755 <dt><b><tt>extractelement (VAL, IDX)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2756 <dd>Perform the <a href="#i_extractelement">extractelement operation</a> on
2757 constants.</dd>
Robert Bocchino7e97a6d2006-01-10 19:31:34 +0000[diff] [blame]2758
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2759 <dt><b><tt>insertelement (VAL, ELT, IDX)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2760 <dd>Perform the <a href="#i_insertelement">insertelement operation</a> on
2761 constants.</dd>
Chris Lattner016a0e52006-04-08 00:13:41 +0000[diff] [blame]2762
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2763 <dt><b><tt>shufflevector (VEC1, VEC2, IDXMASK)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2764 <dd>Perform the <a href="#i_shufflevector">shufflevector operation</a> on
2765 constants.</dd>
Chris Lattner016a0e52006-04-08 00:13:41 +0000[diff] [blame]2766
Nick Lewycky9ab9a7f2010-05-29 06:44:15 +0000[diff] [blame]2767 <dt><b><tt>extractvalue (VAL, IDX0, IDX1, ...)</tt></b></dt>
2768 <dd>Perform the <a href="#i_extractvalue">extractvalue operation</a> on
2769 constants. The index list is interpreted in a similar manner as indices in
2770 a '<a href="#i_getelementptr">getelementptr</a>' operation. At least one
2771 index value must be specified.</dd>
2772
2773 <dt><b><tt>insertvalue (VAL, ELT, IDX0, IDX1, ...)</tt></b></dt>
2774 <dd>Perform the <a href="#i_insertvalue">insertvalue operation</a> on
2775 constants. The index list is interpreted in a similar manner as indices in
2776 a '<a href="#i_getelementptr">getelementptr</a>' operation. At least one
2777 index value must be specified.</dd>
2778
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2779 <dt><b><tt>OPCODE (LHS, RHS)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2780 <dd>Perform the specified operation of the LHS and RHS constants. OPCODE may
2781 be any of the <a href="#binaryops">binary</a>
2782 or <a href="#bitwiseops">bitwise binary</a> operations. The constraints
2783 on operands are the same as those for the corresponding instruction
2784 (e.g. no bitwise operations on floating point values are allowed).</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2785</dl>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2786
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2787</div>
Chris Lattnerb1652612004-03-08 16:49:10 +0000[diff] [blame]2788
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2789</div>
2790
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2791<!-- *********************************************************************** -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2792<h2><a name="othervalues">Other Values</a></h2>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2793<!-- *********************************************************************** -->
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2794<div>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2795<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2796<h3>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2797<a name="inlineasm">Inline Assembler Expressions</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2798</h3>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2799
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2800<div>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2801
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2802<p>LLVM supports inline assembler expressions (as opposed
2803 to <a href="#moduleasm"> Module-Level Inline Assembly</a>) through the use of
2804 a special value. This value represents the inline assembler as a string
2805 (containing the instructions to emit), a list of operand constraints (stored
Dale Johannesen63c94fe2009-10-13 21:56:55 +0000[diff] [blame]2806 as a string), a flag that indicates whether or not the inline asm
Dale Johannesen1cfb9582009-10-21 23:28:00 +0000[diff] [blame]2807 expression has side effects, and a flag indicating whether the function
2808 containing the asm needs to align its stack conservatively. An example
2809 inline assembler expression is:</p>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2810
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2811<pre class="doc_code">
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2812i32 (i32) asm "bswap $0", "=r,r"
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2813</pre>
2814
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2815<p>Inline assembler expressions may <b>only</b> be used as the callee operand of
2816 a <a href="#i_call"><tt>call</tt> instruction</a>. Thus, typically we
2817 have:</p>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2818
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2819<pre class="doc_code">
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2820%X = call i32 asm "<a href="#int_bswap">bswap</a> $0", "=r,r"(i32 %Y)
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2821</pre>
2822
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2823<p>Inline asms with side effects not visible in the constraint list must be
2824 marked as having side effects. This is done through the use of the
2825 '<tt>sideeffect</tt>' keyword, like so:</p>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2826
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2827<pre class="doc_code">
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2828call void asm sideeffect "eieio", ""()
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2829</pre>
2830
Dale Johannesen1cfb9582009-10-21 23:28:00 +0000[diff] [blame]2831<p>In some cases inline asms will contain code that will not work unless the
2832 stack is aligned in some way, such as calls or SSE instructions on x86,
2833 yet will not contain code that does that alignment within the asm.
2834 The compiler should make conservative assumptions about what the asm might
2835 contain and should generate its usual stack alignment code in the prologue
2836 if the '<tt>alignstack</tt>' keyword is present:</p>
Dale Johannesen63c94fe2009-10-13 21:56:55 +0000[diff] [blame]2837
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2838<pre class="doc_code">
Dale Johannesen1cfb9582009-10-21 23:28:00 +0000[diff] [blame]2839call void asm alignstack "eieio", ""()
Dale Johannesen63c94fe2009-10-13 21:56:55 +0000[diff] [blame]2840</pre>
Dale Johannesen63c94fe2009-10-13 21:56:55 +0000[diff] [blame]2841
2842<p>If both keywords appear the '<tt>sideeffect</tt>' keyword must come
2843 first.</p>
2844
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2845<p>TODO: The format of the asm and constraints string still need to be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2846 documented here. Constraints on what can be done (e.g. duplication, moving,
2847 etc need to be documented). This is probably best done by reference to
2848 another document that covers inline asm from a holistic perspective.</p>
Chris Lattner51065562010-04-07 05:38:05 +0000[diff] [blame]2849
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2850<h4>
Chris Lattner51065562010-04-07 05:38:05 +0000[diff] [blame]2851<a name="inlineasm_md">Inline Asm Metadata</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2852</h4>
Chris Lattner51065562010-04-07 05:38:05 +0000[diff] [blame]2853
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2854<div>
Chris Lattner51065562010-04-07 05:38:05 +0000[diff] [blame]2855
2856<p>The call instructions that wrap inline asm nodes may have a "!srcloc" MDNode
Chris Lattner79ffdc72010-11-17 08:20:42 +0000[diff] [blame]2857 attached to it that contains a list of constant integers. If present, the
2858 code generator will use the integer as the location cookie value when report
Chris Lattner51065562010-04-07 05:38:05 +0000[diff] [blame]2859 errors through the LLVMContext error reporting mechanisms. This allows a
Dan Gohman61110ae2010-04-28 00:36:01 +0000[diff] [blame]2860 front-end to correlate backend errors that occur with inline asm back to the
Chris Lattner51065562010-04-07 05:38:05 +0000[diff] [blame]2861 source code that produced it. For example:</p>
2862
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2863<pre class="doc_code">
Chris Lattner51065562010-04-07 05:38:05 +0000[diff] [blame]2864call void asm sideeffect "something bad", ""()<b>, !srcloc !42</b>
2865...
2866!42 = !{ i32 1234567 }
2867</pre>
Chris Lattner51065562010-04-07 05:38:05 +0000[diff] [blame]2868
2869<p>It is up to the front-end to make sense of the magic numbers it places in the
Chris Lattner79ffdc72010-11-17 08:20:42 +0000[diff] [blame]2870 IR. If the MDNode contains multiple constants, the code generator will use
2871 the one that corresponds to the line of the asm that the error occurs on.</p>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2872
2873</div>
2874
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2875</div>
2876
Chris Lattnerc2f8f162010-01-15 21:50:19 +0000[diff] [blame]2877<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2878<h3>
2879 <a name="metadata">Metadata Nodes and Metadata Strings</a>
2880</h3>
Chris Lattnerc2f8f162010-01-15 21:50:19 +0000[diff] [blame]2881
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2882<div>
Chris Lattnerc2f8f162010-01-15 21:50:19 +0000[diff] [blame]2883
2884<p>LLVM IR allows metadata to be attached to instructions in the program that
2885 can convey extra information about the code to the optimizers and code
2886 generator. One example application of metadata is source-level debug
2887 information. There are two metadata primitives: strings and nodes. All
2888 metadata has the <tt>metadata</tt> type and is identified in syntax by a
2889 preceding exclamation point ('<tt>!</tt>').</p>
2890
2891<p>A metadata string is a string surrounded by double quotes. It can contain
Bill Wendlingb6c22202011-11-30 21:43:43 +0000[diff] [blame^]2892 any character by escaping non-printable characters with "<tt>\xx</tt>" where
2893 "<tt>xx</tt>" is the two digit hex code. For example:
2894 "<tt>!"test\00"</tt>".</p>
Chris Lattnerc2f8f162010-01-15 21:50:19 +0000[diff] [blame]2895
2896<p>Metadata nodes are represented with notation similar to structure constants
2897 (a comma separated list of elements, surrounded by braces and preceded by an
Bill Wendlingb6c22202011-11-30 21:43:43 +0000[diff] [blame^]2898 exclamation point). Metadata nodes can have any values as their operand. For
2899 example:</p>
2900
2901<div class="doc_code">
2902<pre>
2903!{ metadata !"test\00", i32 10}
2904</pre>
2905</div>
Chris Lattnerc2f8f162010-01-15 21:50:19 +0000[diff] [blame]2906
2907<p>A <a href="#namedmetadatastructure">named metadata</a> is a collection of
2908 metadata nodes, which can be looked up in the module symbol table. For
Bill Wendlingb6c22202011-11-30 21:43:43 +0000[diff] [blame^]2909 example:</p>
2910
2911<div class="doc_code">
2912<pre>
2913!foo = metadata !{!4, !3}
2914</pre>
2915</div>
Chris Lattnerc2f8f162010-01-15 21:50:19 +0000[diff] [blame]2916
Devang Patel9984bd62010-03-04 23:44:48 +0000[diff] [blame]2917<p>Metadata can be used as function arguments. Here <tt>llvm.dbg.value</tt>
Bill Wendlingb6c22202011-11-30 21:43:43 +0000[diff] [blame^]2918 function is using two metadata arguments:</p>
Devang Patel9984bd62010-03-04 23:44:48 +0000[diff] [blame]2919
Bill Wendlingc0e10672011-03-02 02:17:11 +0000[diff] [blame]2920<div class="doc_code">
2921<pre>
2922call void @llvm.dbg.value(metadata !24, i64 0, metadata !25)
2923</pre>
2924</div>
Devang Patel9984bd62010-03-04 23:44:48 +0000[diff] [blame]2925
2926<p>Metadata can be attached with an instruction. Here metadata <tt>!21</tt> is
Bill Wendlingb6c22202011-11-30 21:43:43 +0000[diff] [blame^]2927 attached to the <tt>add</tt> instruction using the <tt>!dbg</tt>
2928 identifier:</p>
Devang Patel9984bd62010-03-04 23:44:48 +0000[diff] [blame]2929
Bill Wendlingc0e10672011-03-02 02:17:11 +0000[diff] [blame]2930<div class="doc_code">
2931<pre>
2932%indvar.next = add i64 %indvar, 1, !dbg !21
2933</pre>
2934</div>
2935
Peter Collingbourneec9ff672011-10-27 19:19:07 +0000[diff] [blame]2936<p>More information about specific metadata nodes recognized by the optimizers
2937 and code generator is found below.</p>
2938
Bill Wendlingb6c22202011-11-30 21:43:43 +0000[diff] [blame^]2939<!-- _______________________________________________________________________ -->
Peter Collingbourneec9ff672011-10-27 19:19:07 +0000[diff] [blame]2940<h4>
2941 <a name="tbaa">'<tt>tbaa</tt>' Metadata</a>
2942</h4>
2943
2944<div>
2945
2946<p>In LLVM IR, memory does not have types, so LLVM's own type system is not
2947 suitable for doing TBAA. Instead, metadata is added to the IR to describe
2948 a type system of a higher level language. This can be used to implement
2949 typical C/C++ TBAA, but it can also be used to implement custom alias
2950 analysis behavior for other languages.</p>
2951
2952<p>The current metadata format is very simple. TBAA metadata nodes have up to
2953 three fields, e.g.:</p>
2954
2955<div class="doc_code">
2956<pre>
2957!0 = metadata !{ metadata !"an example type tree" }
2958!1 = metadata !{ metadata !"int", metadata !0 }
2959!2 = metadata !{ metadata !"float", metadata !0 }
2960!3 = metadata !{ metadata !"const float", metadata !2, i64 1 }
2961</pre>
2962</div>
2963
2964<p>The first field is an identity field. It can be any value, usually
2965 a metadata string, which uniquely identifies the type. The most important
2966 name in the tree is the name of the root node. Two trees with
2967 different root node names are entirely disjoint, even if they
2968 have leaves with common names.</p>
2969
2970<p>The second field identifies the type's parent node in the tree, or
2971 is null or omitted for a root node. A type is considered to alias
2972 all of its descendants and all of its ancestors in the tree. Also,
2973 a type is considered to alias all types in other trees, so that
2974 bitcode produced from multiple front-ends is handled conservatively.</p>
2975
2976<p>If the third field is present, it's an integer which if equal to 1
2977 indicates that the type is "constant" (meaning
2978 <tt>pointsToConstantMemory</tt> should return true; see
2979 <a href="AliasAnalysis.html#OtherItfs">other useful
2980 <tt>AliasAnalysis</tt> methods</a>).</p>
2981
2982</div>
2983
Bill Wendlingb6c22202011-11-30 21:43:43 +0000[diff] [blame^]2984<!-- _______________________________________________________________________ -->
Peter Collingbournef7d1e7b2011-10-27 19:19:14 +0000[diff] [blame]2985<h4>
2986 <a name="fpaccuracy">'<tt>fpaccuracy</tt>' Metadata</a>
2987</h4>
2988
2989<div>
2990
2991<p><tt>fpaccuracy</tt> metadata may be attached to any instruction of floating
2992 point type. It expresses the maximum relative error of the result of
2993 that instruction, in ULPs. ULP is defined as follows:</p>
2994
Bill Wendling302d7ce2011-11-09 19:33:56 +0000[diff] [blame]2995<blockquote>
2996
2997<p>If <tt>x</tt> is a real number that lies between two finite consecutive
2998 floating-point numbers <tt>a</tt> and <tt>b</tt>, without being equal to one
2999 of them, then <tt>ulp(x) = |b - a|</tt>, otherwise <tt>ulp(x)</tt> is the
3000 distance between the two non-equal finite floating-point numbers nearest
3001 <tt>x</tt>. Moreover, <tt>ulp(NaN)</tt> is <tt>NaN</tt>.</p>
3002
3003</blockquote>
Peter Collingbournef7d1e7b2011-10-27 19:19:14 +0000[diff] [blame]3004
3005<p>The maximum relative error may be any rational number. The metadata node
3006 shall consist of a pair of unsigned integers respectively representing
3007 the numerator and denominator. For example, 2.5 ULP:</p>
3008
3009<div class="doc_code">
3010<pre>
3011!0 = metadata !{ i32 5, i32 2 }
3012</pre>
3013</div>
3014
3015</div>
3016
Chris Lattnerc2f8f162010-01-15 21:50:19 +0000[diff] [blame]3017</div>
3018
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3019</div>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]3020
3021<!-- *********************************************************************** -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3022<h2>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]3023 <a name="intrinsic_globals">Intrinsic Global Variables</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3024</h2>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]3025<!-- *********************************************************************** -->
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3026<div>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]3027<p>LLVM has a number of "magic" global variables that contain data that affect
3028code generation or other IR semantics. These are documented here. All globals
Chris Lattner58f9bb22009-07-20 06:14:25 +0000[diff] [blame]3029of this sort should have a section specified as "<tt>llvm.metadata</tt>". This
3030section and all globals that start with "<tt>llvm.</tt>" are reserved for use
3031by LLVM.</p>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]3032
3033<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3034<h3>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]3035<a name="intg_used">The '<tt>llvm.used</tt>' Global Variable</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3036</h3>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]3037
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3038<div>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]3039
3040<p>The <tt>@llvm.used</tt> global is an array with i8* element type which has <a
3041href="#linkage_appending">appending linkage</a>. This array contains a list of
3042pointers to global variables and functions which may optionally have a pointer
3043cast formed of bitcast or getelementptr. For example, a legal use of it is:</p>
3044
Bill Wendling1654bb22011-11-08 00:32:45 +0000[diff] [blame]3045<div class="doc_code">
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]3046<pre>
Bill Wendling1654bb22011-11-08 00:32:45 +0000[diff] [blame]3047@X = global i8 4
3048@Y = global i32 123
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]3049
Bill Wendling1654bb22011-11-08 00:32:45 +0000[diff] [blame]3050@llvm.used = appending global [2 x i8*] [
3051 i8* @X,
3052 i8* bitcast (i32* @Y to i8*)
3053], section "llvm.metadata"
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]3054</pre>
Bill Wendling1654bb22011-11-08 00:32:45 +0000[diff] [blame]3055</div>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]3056
3057<p>If a global variable appears in the <tt>@llvm.used</tt> list, then the
Bill Wendling1654bb22011-11-08 00:32:45 +0000[diff] [blame]3058 compiler, assembler, and linker are required to treat the symbol as if there
3059 is a reference to the global that it cannot see. For example, if a variable
3060 has internal linkage and no references other than that from
3061 the <tt>@llvm.used</tt> list, it cannot be deleted. This is commonly used to
3062 represent references from inline asms and other things the compiler cannot
3063 "see", and corresponds to "<tt>attribute((used))</tt>" in GNU C.</p>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]3064
3065<p>On some targets, the code generator must emit a directive to the assembler or
Bill Wendling1654bb22011-11-08 00:32:45 +0000[diff] [blame]3066 object file to prevent the assembler and linker from molesting the
3067 symbol.</p>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]3068
3069</div>
3070
3071<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3072<h3>
3073 <a name="intg_compiler_used">
3074 The '<tt>llvm.compiler.used</tt>' Global Variable
3075 </a>
3076</h3>
Chris Lattner58f9bb22009-07-20 06:14:25 +0000[diff] [blame]3077
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3078<div>
Chris Lattner58f9bb22009-07-20 06:14:25 +0000[diff] [blame]3079
3080<p>The <tt>@llvm.compiler.used</tt> directive is the same as the
Bill Wendling1654bb22011-11-08 00:32:45 +0000[diff] [blame]3081 <tt>@llvm.used</tt> directive, except that it only prevents the compiler from
3082 touching the symbol. On targets that support it, this allows an intelligent
3083 linker to optimize references to the symbol without being impeded as it would
3084 be by <tt>@llvm.used</tt>.</p>
Chris Lattner58f9bb22009-07-20 06:14:25 +0000[diff] [blame]3085
3086<p>This is a rare construct that should only be used in rare circumstances, and
Bill Wendling1654bb22011-11-08 00:32:45 +0000[diff] [blame]3087 should not be exposed to source languages.</p>
Chris Lattner58f9bb22009-07-20 06:14:25 +0000[diff] [blame]3088
3089</div>
3090
3091<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3092<h3>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]3093<a name="intg_global_ctors">The '<tt>llvm.global_ctors</tt>' Global Variable</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3094</h3>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]3095
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3096<div>
Bill Wendling1654bb22011-11-08 00:32:45 +0000[diff] [blame]3097
3098<div class="doc_code">
David Chisnalla9d4a6f2010-04-30 19:23:49 +0000[diff] [blame]3099<pre>
3100%0 = type { i32, void ()* }
David Chisnallb492b812010-04-30 19:27:35 +0000[diff] [blame]3101@llvm.global_ctors = appending global [1 x %0] [%0 { i32 65535, void ()* @ctor }]
David Chisnalla9d4a6f2010-04-30 19:23:49 +0000[diff] [blame]3102</pre>
Bill Wendling1654bb22011-11-08 00:32:45 +0000[diff] [blame]3103</div>
3104
3105<p>The <tt>@llvm.global_ctors</tt> array contains a list of constructor
3106 functions and associated priorities. The functions referenced by this array
3107 will be called in ascending order of priority (i.e. lowest first) when the
3108 module is loaded. The order of functions with the same priority is not
3109 defined.</p>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]3110
3111</div>
3112
3113<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3114<h3>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]3115<a name="intg_global_dtors">The '<tt>llvm.global_dtors</tt>' Global Variable</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3116</h3>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]3117
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3118<div>
Bill Wendling1654bb22011-11-08 00:32:45 +0000[diff] [blame]3119
3120<div class="doc_code">
David Chisnalla9d4a6f2010-04-30 19:23:49 +0000[diff] [blame]3121<pre>
3122%0 = type { i32, void ()* }
David Chisnallb492b812010-04-30 19:27:35 +0000[diff] [blame]3123@llvm.global_dtors = appending global [1 x %0] [%0 { i32 65535, void ()* @dtor }]
David Chisnalla9d4a6f2010-04-30 19:23:49 +0000[diff] [blame]3124</pre>
Bill Wendling1654bb22011-11-08 00:32:45 +0000[diff] [blame]3125</div>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]3126
Bill Wendling1654bb22011-11-08 00:32:45 +0000[diff] [blame]3127<p>The <tt>@llvm.global_dtors</tt> array contains a list of destructor functions
3128 and associated priorities. The functions referenced by this array will be
3129 called in descending order of priority (i.e. highest first) when the module
3130 is loaded. The order of functions with the same priority is not defined.</p>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]3131
3132</div>
3133
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3134</div>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]3135
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]3136<!-- *********************************************************************** -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3137<h2><a name="instref">Instruction Reference</a></h2>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3138<!-- *********************************************************************** -->
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]3139
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3140<div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]3141
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3142<p>The LLVM instruction set consists of several different classifications of
3143 instructions: <a href="#terminators">terminator
3144 instructions</a>, <a href="#binaryops">binary instructions</a>,
3145 <a href="#bitwiseops">bitwise binary instructions</a>,
3146 <a href="#memoryops">memory instructions</a>, and
3147 <a href="#otherops">other instructions</a>.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]3148
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3149<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3150<h3>
3151 <a name="terminators">Terminator Instructions</a>
3152</h3>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]3153
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3154<div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]3155
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3156<p>As mentioned <a href="#functionstructure">previously</a>, every basic block
3157 in a program ends with a "Terminator" instruction, which indicates which
3158 block should be executed after the current block is finished. These
3159 terminator instructions typically yield a '<tt>void</tt>' value: they produce
3160 control flow, not values (the one exception being the
3161 '<a href="#i_invoke"><tt>invoke</tt></a>' instruction).</p>
3162
Chris Lattnerd3d65ab2011-08-02 20:29:13 +0000[diff] [blame]3163<p>The terminator instructions are:
3164 '<a href="#i_ret"><tt>ret</tt></a>',
3165 '<a href="#i_br"><tt>br</tt></a>',
3166 '<a href="#i_switch"><tt>switch</tt></a>',
3167 '<a href="#i_indirectbr"><tt>indirectbr</tt></a>',
3168 '<a href="#i_invoke"><tt>invoke</tt></a>',
3169 '<a href="#i_unwind"><tt>unwind</tt></a>',
3170 '<a href="#i_resume"><tt>resume</tt></a>', and
3171 '<a href="#i_unreachable"><tt>unreachable</tt></a>'.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]3172
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3173<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3174<h4>
3175 <a name="i_ret">'<tt>ret</tt>' Instruction</a>
3176</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3177
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3178<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3179
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3180<h5>Syntax:</h5>
Dan Gohmancc3132e2008-10-04 19:00:07 +0000[diff] [blame]3181<pre>
3182 ret &lt;type&gt; &lt;value&gt; <i>; Return a value from a non-void function</i>
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]3183 ret void <i>; Return from void function</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3184</pre>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]3185
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3186<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3187<p>The '<tt>ret</tt>' instruction is used to return control flow (and optionally
3188 a value) from a function back to the caller.</p>
3189
3190<p>There are two forms of the '<tt>ret</tt>' instruction: one that returns a
3191 value and then causes control flow, and one that just causes control flow to
3192 occur.</p>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]3193
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3194<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3195<p>The '<tt>ret</tt>' instruction optionally accepts a single argument, the
3196 return value. The type of the return value must be a
3197 '<a href="#t_firstclass">first class</a>' type.</p>
Dan Gohmancc3132e2008-10-04 19:00:07 +0000[diff] [blame]3198
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3199<p>A function is not <a href="#wellformed">well formed</a> if it it has a
3200 non-void return type and contains a '<tt>ret</tt>' instruction with no return
3201 value or a return value with a type that does not match its type, or if it
3202 has a void return type and contains a '<tt>ret</tt>' instruction with a
3203 return value.</p>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]3204
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3205<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3206<p>When the '<tt>ret</tt>' instruction is executed, control flow returns back to
3207 the calling function's context. If the caller is a
3208 "<a href="#i_call"><tt>call</tt></a>" instruction, execution continues at the
3209 instruction after the call. If the caller was an
3210 "<a href="#i_invoke"><tt>invoke</tt></a>" instruction, execution continues at
3211 the beginning of the "normal" destination block. If the instruction returns
3212 a value, that value shall set the call or invoke instruction's return
3213 value.</p>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]3214
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3215<h5>Example:</h5>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]3216<pre>
3217 ret i32 5 <i>; Return an integer value of 5</i>
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]3218 ret void <i>; Return from a void function</i>
Bill Wendling050ee8f2009-02-28 22:12:54 +0000[diff] [blame]3219 ret { i32, i8 } { i32 4, i8 2 } <i>; Return a struct of values 4 and 2</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3220</pre>
Dan Gohman3065b612009-01-12 23:12:39 +0000[diff] [blame]3221
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3222</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3223<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3224<h4>
3225 <a name="i_br">'<tt>br</tt>' Instruction</a>
3226</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3227
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3228<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3229
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3230<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3231<pre>
Bill Wendling16b86742011-07-26 10:41:15 +0000[diff] [blame]3232 br i1 &lt;cond&gt;, label &lt;iftrue&gt;, label &lt;iffalse&gt;
3233 br label &lt;dest&gt; <i>; Unconditional branch</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3234</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3235
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3236<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3237<p>The '<tt>br</tt>' instruction is used to cause control flow to transfer to a
3238 different basic block in the current function. There are two forms of this
3239 instruction, corresponding to a conditional branch and an unconditional
3240 branch.</p>
3241
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3242<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3243<p>The conditional branch form of the '<tt>br</tt>' instruction takes a single
3244 '<tt>i1</tt>' value and two '<tt>label</tt>' values. The unconditional form
3245 of the '<tt>br</tt>' instruction takes a single '<tt>label</tt>' value as a
3246 target.</p>
3247
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3248<h5>Semantics:</h5>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]3249<p>Upon execution of a conditional '<tt>br</tt>' instruction, the '<tt>i1</tt>'
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3250 argument is evaluated. If the value is <tt>true</tt>, control flows to the
3251 '<tt>iftrue</tt>' <tt>label</tt> argument. If "cond" is <tt>false</tt>,
3252 control flows to the '<tt>iffalse</tt>' <tt>label</tt> argument.</p>
3253
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3254<h5>Example:</h5>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]3255<pre>
3256Test:
3257 %cond = <a href="#i_icmp">icmp</a> eq i32 %a, %b
3258 br i1 %cond, label %IfEqual, label %IfUnequal
3259IfEqual:
3260 <a href="#i_ret">ret</a> i32 1
3261IfUnequal:
3262 <a href="#i_ret">ret</a> i32 0
3263</pre>
3264
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3265</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3266
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3267<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3268<h4>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]3269 <a name="i_switch">'<tt>switch</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3270</h4>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]3271
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3272<div>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]3273
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3274<h5>Syntax:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]3275<pre>
3276 switch &lt;intty&gt; &lt;value&gt;, label &lt;defaultdest&gt; [ &lt;intty&gt; &lt;val&gt;, label &lt;dest&gt; ... ]
3277</pre>
3278
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3279<h5>Overview:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]3280<p>The '<tt>switch</tt>' instruction is used to transfer control flow to one of
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3281 several different places. It is a generalization of the '<tt>br</tt>'
3282 instruction, allowing a branch to occur to one of many possible
3283 destinations.</p>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]3284
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3285<h5>Arguments:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]3286<p>The '<tt>switch</tt>' instruction uses three parameters: an integer
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3287 comparison value '<tt>value</tt>', a default '<tt>label</tt>' destination,
3288 and an array of pairs of comparison value constants and '<tt>label</tt>'s.
3289 The table is not allowed to contain duplicate constant entries.</p>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]3290
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3291<h5>Semantics:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3292<p>The <tt>switch</tt> instruction specifies a table of values and
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3293 destinations. When the '<tt>switch</tt>' instruction is executed, this table
3294 is searched for the given value. If the value is found, control flow is
Benjamin Kramer0f420382009-10-12 14:46:08 +0000[diff] [blame]3295 transferred to the corresponding destination; otherwise, control flow is
3296 transferred to the default destination.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3297
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]3298<h5>Implementation:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]3299<p>Depending on properties of the target machine and the particular
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3300 <tt>switch</tt> instruction, this instruction may be code generated in
3301 different ways. For example, it could be generated as a series of chained
3302 conditional branches or with a lookup table.</p>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]3303
3304<h5>Example:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]3305<pre>
3306 <i>; Emulate a conditional br instruction</i>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]3307 %Val = <a href="#i_zext">zext</a> i1 %value to i32
Dan Gohman623806e2009-01-04 23:44:43 +0000[diff] [blame]3308 switch i32 %Val, label %truedest [ i32 0, label %falsedest ]
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]3309
3310 <i>; Emulate an unconditional br instruction</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3311 switch i32 0, label %dest [ ]
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]3312
3313 <i>; Implement a jump table:</i>
Dan Gohman623806e2009-01-04 23:44:43 +0000[diff] [blame]3314 switch i32 %val, label %otherwise [ i32 0, label %onzero
3315 i32 1, label %onone
3316 i32 2, label %ontwo ]
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3317</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3318
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3319</div>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3320
Chris Lattner3ed871f2009-10-27 19:13:16 +0000[diff] [blame]3321
3322<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3323<h4>
Chris Lattnerd04cb6d2009-10-28 00:19:10 +0000[diff] [blame]3324 <a name="i_indirectbr">'<tt>indirectbr</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3325</h4>
Chris Lattner3ed871f2009-10-27 19:13:16 +0000[diff] [blame]3326
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3327<div>
Chris Lattner3ed871f2009-10-27 19:13:16 +0000[diff] [blame]3328
3329<h5>Syntax:</h5>
3330<pre>
Chris Lattnerd04cb6d2009-10-28 00:19:10 +0000[diff] [blame]3331 indirectbr &lt;somety&gt;* &lt;address&gt;, [ label &lt;dest1&gt;, label &lt;dest2&gt;, ... ]
Chris Lattner3ed871f2009-10-27 19:13:16 +0000[diff] [blame]3332</pre>
3333
3334<h5>Overview:</h5>
3335
Chris Lattnerd04cb6d2009-10-28 00:19:10 +0000[diff] [blame]3336<p>The '<tt>indirectbr</tt>' instruction implements an indirect branch to a label
Chris Lattner3ed871f2009-10-27 19:13:16 +0000[diff] [blame]3337 within the current function, whose address is specified by
Chris Lattnere4801f72009-10-27 21:01:34 +0000[diff] [blame]3338 "<tt>address</tt>". Address must be derived from a <a
3339 href="#blockaddress">blockaddress</a> constant.</p>
Chris Lattner3ed871f2009-10-27 19:13:16 +0000[diff] [blame]3340
3341<h5>Arguments:</h5>
3342
3343<p>The '<tt>address</tt>' argument is the address of the label to jump to. The
3344 rest of the arguments indicate the full set of possible destinations that the
3345 address may point to. Blocks are allowed to occur multiple times in the
3346 destination list, though this isn't particularly useful.</p>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3347
Chris Lattner3ed871f2009-10-27 19:13:16 +0000[diff] [blame]3348<p>This destination list is required so that dataflow analysis has an accurate
3349 understanding of the CFG.</p>
3350
3351<h5>Semantics:</h5>
3352
3353<p>Control transfers to the block specified in the address argument. All
3354 possible destination blocks must be listed in the label list, otherwise this
3355 instruction has undefined behavior. This implies that jumps to labels
3356 defined in other functions have undefined behavior as well.</p>
3357
3358<h5>Implementation:</h5>
3359
3360<p>This is typically implemented with a jump through a register.</p>
3361
3362<h5>Example:</h5>
3363<pre>
Chris Lattnerd04cb6d2009-10-28 00:19:10 +0000[diff] [blame]3364 indirectbr i8* %Addr, [ label %bb1, label %bb2, label %bb3 ]
Chris Lattner3ed871f2009-10-27 19:13:16 +0000[diff] [blame]3365</pre>
3366
3367</div>
3368
3369
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3370<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3371<h4>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3372 <a name="i_invoke">'<tt>invoke</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3373</h4>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3374
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3375<div>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3376
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3377<h5>Syntax:</h5>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3378<pre>
Devang Patel02256232008-10-07 17:48:33 +0000[diff] [blame]3379 &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 Lattner6b7a0082006-05-14 18:23:06 +0000[diff] [blame]3380 to label &lt;normal label&gt; unwind label &lt;exception label&gt;
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3381</pre>
3382
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]3383<h5>Overview:</h5>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3384<p>The '<tt>invoke</tt>' instruction causes control to transfer to a specified
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3385 function, with the possibility of control flow transfer to either the
3386 '<tt>normal</tt>' label or the '<tt>exception</tt>' label. If the callee
3387 function returns with the "<tt><a href="#i_ret">ret</a></tt>" instruction,
3388 control flow will return to the "normal" label. If the callee (or any
3389 indirect callees) returns with the "<a href="#i_unwind"><tt>unwind</tt></a>"
3390 instruction, control is interrupted and continued at the dynamically nearest
3391 "exception" label.</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3392
Bill Wendlingbbcb7cd2011-08-02 21:52:38 +0000[diff] [blame]3393<p>The '<tt>exception</tt>' label is a
3394 <i><a href="ExceptionHandling.html#overview">landing pad</a></i> for the
3395 exception. As such, '<tt>exception</tt>' label is required to have the
3396 "<a href="#i_landingpad"><tt>landingpad</tt></a>" instruction, which contains
3397 the information about about the behavior of the program after unwinding
3398 happens, as its first non-PHI instruction. The restrictions on the
3399 "<tt>landingpad</tt>" instruction's tightly couples it to the
3400 "<tt>invoke</tt>" instruction, so that the important information contained
3401 within the "<tt>landingpad</tt>" instruction can't be lost through normal
3402 code motion.</p>
3403
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3404<h5>Arguments:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3405<p>This instruction requires several arguments:</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3406
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3407<ol>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3408 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
3409 convention</a> the call should use. If none is specified, the call
3410 defaults to using C calling conventions.</li>
Devang Patel7e9b05e2008-10-06 18:50:38 +0000[diff] [blame]3411
3412 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3413 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
3414 '<tt>inreg</tt>' attributes are valid here.</li>
Devang Patel7e9b05e2008-10-06 18:50:38 +0000[diff] [blame]3415
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3416 <li>'<tt>ptr to function ty</tt>': shall be the signature of the pointer to
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3417 function value being invoked. In most cases, this is a direct function
3418 invocation, but indirect <tt>invoke</tt>s are just as possible, branching
3419 off an arbitrary pointer to function value.</li>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3420
3421 <li>'<tt>function ptr val</tt>': An LLVM value containing a pointer to a
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3422 function to be invoked. </li>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3423
3424 <li>'<tt>function args</tt>': argument list whose types match the function
Chris Lattner47f2a832010-03-02 06:36:51 +0000[diff] [blame]3425 signature argument types and parameter attributes. All arguments must be
3426 of <a href="#t_firstclass">first class</a> type. If the function
3427 signature indicates the function accepts a variable number of arguments,
3428 the extra arguments can be specified.</li>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3429
3430 <li>'<tt>normal label</tt>': the label reached when the called function
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3431 executes a '<tt><a href="#i_ret">ret</a></tt>' instruction. </li>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3432
3433 <li>'<tt>exception label</tt>': the label reached when a callee returns with
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3434 the <a href="#i_unwind"><tt>unwind</tt></a> instruction. </li>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3435
Devang Patel02256232008-10-07 17:48:33 +0000[diff] [blame]3436 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3437 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
3438 '<tt>readnone</tt>' attributes are valid here.</li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3439</ol>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3440
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3441<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3442<p>This instruction is designed to operate as a standard
3443 '<tt><a href="#i_call">call</a></tt>' instruction in most regards. The
3444 primary difference is that it establishes an association with a label, which
3445 is used by the runtime library to unwind the stack.</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3446
3447<p>This instruction is used in languages with destructors to ensure that proper
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3448 cleanup is performed in the case of either a <tt>longjmp</tt> or a thrown
3449 exception. Additionally, this is important for implementation of
3450 '<tt>catch</tt>' clauses in high-level languages that support them.</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3451
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3452<p>For the purposes of the SSA form, the definition of the value returned by the
3453 '<tt>invoke</tt>' instruction is deemed to occur on the edge from the current
3454 block to the "normal" label. If the callee unwinds then no return value is
3455 available.</p>
Dan Gohman9069d892009-05-22 21:47:08 +0000[diff] [blame]3456
Chris Lattner97257f82010-01-15 18:08:37 +0000[diff] [blame]3457<p>Note that the code generator does not yet completely support unwind, and
3458that the invoke/unwind semantics are likely to change in future versions.</p>
3459
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3460<h5>Example:</h5>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3461<pre>
Nick Lewycky084ab472008-03-16 07:18:12 +0000[diff] [blame]3462 %retval = invoke i32 @Test(i32 15) to label %Continue
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]3463 unwind label %TestCleanup <i>; {i32}:retval set</i>
Nick Lewycky084ab472008-03-16 07:18:12 +0000[diff] [blame]3464 %retval = invoke <a href="#callingconv">coldcc</a> i32 %Testfnptr(i32 15) to label %Continue
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]3465 unwind label %TestCleanup <i>; {i32}:retval set</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3466</pre>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3467
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3468</div>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3469
Chris Lattner5ed60612003-09-03 00:41:47 +0000[diff] [blame]3470<!-- _______________________________________________________________________ -->
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3471
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3472<h4>
3473 <a name="i_unwind">'<tt>unwind</tt>' Instruction</a>
3474</h4>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3475
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3476<div>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3477
Chris Lattner5ed60612003-09-03 00:41:47 +0000[diff] [blame]3478<h5>Syntax:</h5>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3479<pre>
3480 unwind
3481</pre>
3482
Chris Lattner5ed60612003-09-03 00:41:47 +0000[diff] [blame]3483<h5>Overview:</h5>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3484<p>The '<tt>unwind</tt>' instruction unwinds the stack, continuing control flow
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3485 at the first callee in the dynamic call stack which used
3486 an <a href="#i_invoke"><tt>invoke</tt></a> instruction to perform the call.
3487 This is primarily used to implement exception handling.</p>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3488
Chris Lattner5ed60612003-09-03 00:41:47 +0000[diff] [blame]3489<h5>Semantics:</h5>
Chris Lattnerfe8519c2008-04-19 21:01:16 +0000[diff] [blame]3490<p>The '<tt>unwind</tt>' instruction causes execution of the current function to
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3491 immediately halt. The dynamic call stack is then searched for the
3492 first <a href="#i_invoke"><tt>invoke</tt></a> instruction on the call stack.
3493 Once found, execution continues at the "exceptional" destination block
3494 specified by the <tt>invoke</tt> instruction. If there is no <tt>invoke</tt>
3495 instruction in the dynamic call chain, undefined behavior results.</p>
3496
Chris Lattner97257f82010-01-15 18:08:37 +0000[diff] [blame]3497<p>Note that the code generator does not yet completely support unwind, and
3498that the invoke/unwind semantics are likely to change in future versions.</p>
3499
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3500</div>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3501
Bill Wendlingf891bf82011-07-31 06:30:59 +0000[diff] [blame]3502 <!-- _______________________________________________________________________ -->
3503
3504<h4>
3505 <a name="i_resume">'<tt>resume</tt>' Instruction</a>
3506</h4>
3507
3508<div>
3509
3510<h5>Syntax:</h5>
3511<pre>
3512 resume &lt;type&gt; &lt;value&gt;
3513</pre>
3514
3515<h5>Overview:</h5>
3516<p>The '<tt>resume</tt>' instruction is a terminator instruction that has no
3517 successors.</p>
3518
3519<h5>Arguments:</h5>
Bill Wendlingbbcb7cd2011-08-02 21:52:38 +0000[diff] [blame]3520<p>The '<tt>resume</tt>' instruction requires one argument, which must have the
Bill Wendlingc5a13612011-08-03 18:37:32 +0000[diff] [blame]3521 same type as the result of any '<tt>landingpad</tt>' instruction in the same
3522 function.</p>
Bill Wendlingf891bf82011-07-31 06:30:59 +0000[diff] [blame]3523
3524<h5>Semantics:</h5>
3525<p>The '<tt>resume</tt>' instruction resumes propagation of an existing
3526 (in-flight) exception whose unwinding was interrupted with
Bill Wendlingbbcb7cd2011-08-02 21:52:38 +0000[diff] [blame]3527 a <a href="#i_landingpad"><tt>landingpad</tt></a> instruction.</p>
Bill Wendlingf891bf82011-07-31 06:30:59 +0000[diff] [blame]3528
3529<h5>Example:</h5>
3530<pre>
Bill Wendlingbbcb7cd2011-08-02 21:52:38 +0000[diff] [blame]3531 resume { i8*, i32 } %exn
Bill Wendlingf891bf82011-07-31 06:30:59 +0000[diff] [blame]3532</pre>
3533
3534</div>
3535
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3536<!-- _______________________________________________________________________ -->
3537
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3538<h4>
3539 <a name="i_unreachable">'<tt>unreachable</tt>' Instruction</a>
3540</h4>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3541
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3542<div>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3543
3544<h5>Syntax:</h5>
3545<pre>
3546 unreachable
3547</pre>
3548
3549<h5>Overview:</h5>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3550<p>The '<tt>unreachable</tt>' instruction has no defined semantics. This
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3551 instruction is used to inform the optimizer that a particular portion of the
3552 code is not reachable. This can be used to indicate that the code after a
3553 no-return function cannot be reached, and other facts.</p>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3554
3555<h5>Semantics:</h5>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3556<p>The '<tt>unreachable</tt>' instruction has no defined semantics.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3557
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3558</div>
3559
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3560</div>
3561
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3562<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3563<h3>
3564 <a name="binaryops">Binary Operations</a>
3565</h3>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3566
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3567<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3568
3569<p>Binary operators are used to do most of the computation in a program. They
3570 require two operands of the same type, execute an operation on them, and
3571 produce a single value. The operands might represent multiple data, as is
3572 the case with the <a href="#t_vector">vector</a> data type. The result value
3573 has the same type as its operands.</p>
3574
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3575<p>There are several different binary operators:</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3576
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3577<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3578<h4>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3579 <a name="i_add">'<tt>add</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3580</h4>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3581
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3582<div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3583
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3584<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3585<pre>
Dan Gohmanb07de442009-07-20 22:41:19 +0000[diff] [blame]3586 &lt;result&gt; = add &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Dan Gohman957b1312009-09-02 17:31:42 +0000[diff] [blame]3587 &lt;result&gt; = add nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3588 &lt;result&gt; = add nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3589 &lt;result&gt; = add nuw nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3590</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3591
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3592<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3593<p>The '<tt>add</tt>' instruction returns the sum of its two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3594
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3595<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3596<p>The two arguments to the '<tt>add</tt>' instruction must
3597 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3598 integer values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3599
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3600<h5>Semantics:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3601<p>The value produced is the integer sum of the two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3602
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3603<p>If the sum has unsigned overflow, the result returned is the mathematical
3604 result modulo 2<sup>n</sup>, where n is the bit width of the result.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3605
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3606<p>Because LLVM integers use a two's complement representation, this instruction
3607 is appropriate for both signed and unsigned integers.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3608
Dan Gohman902dfff2009-07-22 22:44:56 +0000[diff] [blame]3609<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3610 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3611 <tt>nsw</tt> keywords are present, the result value of the <tt>add</tt>
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]3612 is a <a href="#trapvalues">trap value</a> if unsigned and/or signed overflow,
3613 respectively, occurs.</p>
Dan Gohmanb07de442009-07-20 22:41:19 +0000[diff] [blame]3614
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3615<h5>Example:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3616<pre>
3617 &lt;result&gt; = add i32 4, %var <i>; yields {i32}:result = 4 + %var</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3618</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3619
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3620</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3621
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3622<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3623<h4>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3624 <a name="i_fadd">'<tt>fadd</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3625</h4>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3626
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3627<div>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3628
3629<h5>Syntax:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3630<pre>
3631 &lt;result&gt; = fadd &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3632</pre>
3633
3634<h5>Overview:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3635<p>The '<tt>fadd</tt>' instruction returns the sum of its two operands.</p>
3636
3637<h5>Arguments:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3638<p>The two arguments to the '<tt>fadd</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3639 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3640 floating point values. Both arguments must have identical types.</p>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3641
3642<h5>Semantics:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3643<p>The value produced is the floating point sum of the two operands.</p>
3644
3645<h5>Example:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3646<pre>
3647 &lt;result&gt; = fadd float 4.0, %var <i>; yields {float}:result = 4.0 + %var</i>
3648</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3649
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3650</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3651
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3652<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3653<h4>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3654 <a name="i_sub">'<tt>sub</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3655</h4>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3656
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3657<div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3658
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3659<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3660<pre>
Dan Gohman902dfff2009-07-22 22:44:56 +0000[diff] [blame]3661 &lt;result&gt; = sub &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Dan Gohman957b1312009-09-02 17:31:42 +0000[diff] [blame]3662 &lt;result&gt; = sub nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3663 &lt;result&gt; = sub nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3664 &lt;result&gt; = sub nuw nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3665</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3666
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3667<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3668<p>The '<tt>sub</tt>' instruction returns the difference of its two
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3669 operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3670
3671<p>Note that the '<tt>sub</tt>' instruction is used to represent the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3672 '<tt>neg</tt>' instruction present in most other intermediate
3673 representations.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3674
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3675<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3676<p>The two arguments to the '<tt>sub</tt>' instruction must
3677 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3678 integer values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3679
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3680<h5>Semantics:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3681<p>The value produced is the integer difference of the two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3682
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3683<p>If the difference has unsigned overflow, the result returned is the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3684 mathematical result modulo 2<sup>n</sup>, where n is the bit width of the
3685 result.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3686
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3687<p>Because LLVM integers use a two's complement representation, this instruction
3688 is appropriate for both signed and unsigned integers.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3689
Dan Gohman902dfff2009-07-22 22:44:56 +0000[diff] [blame]3690<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3691 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3692 <tt>nsw</tt> keywords are present, the result value of the <tt>sub</tt>
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]3693 is a <a href="#trapvalues">trap value</a> if unsigned and/or signed overflow,
3694 respectively, occurs.</p>
Dan Gohmanb07de442009-07-20 22:41:19 +0000[diff] [blame]3695
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3696<h5>Example:</h5>
Bill Wendling2d8b9a82007-05-29 09:42:13 +0000[diff] [blame]3697<pre>
3698 &lt;result&gt; = sub i32 4, %var <i>; yields {i32}:result = 4 - %var</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3699 &lt;result&gt; = sub i32 0, %val <i>; yields {i32}:result = -%var</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3700</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3701
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3702</div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3703
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3704<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3705<h4>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3706 <a name="i_fsub">'<tt>fsub</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3707</h4>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3708
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3709<div>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3710
3711<h5>Syntax:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3712<pre>
3713 &lt;result&gt; = fsub &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3714</pre>
3715
3716<h5>Overview:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3717<p>The '<tt>fsub</tt>' instruction returns the difference of its two
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3718 operands.</p>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3719
3720<p>Note that the '<tt>fsub</tt>' instruction is used to represent the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3721 '<tt>fneg</tt>' instruction present in most other intermediate
3722 representations.</p>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3723
3724<h5>Arguments:</h5>
Bill Wendling972b7202009-07-20 02:32:41 +0000[diff] [blame]3725<p>The two arguments to the '<tt>fsub</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3726 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3727 floating point values. Both arguments must have identical types.</p>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3728
3729<h5>Semantics:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3730<p>The value produced is the floating point difference of the two operands.</p>
3731
3732<h5>Example:</h5>
3733<pre>
3734 &lt;result&gt; = fsub float 4.0, %var <i>; yields {float}:result = 4.0 - %var</i>
3735 &lt;result&gt; = fsub float -0.0, %val <i>; yields {float}:result = -%var</i>
3736</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3737
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3738</div>
3739
3740<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3741<h4>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3742 <a name="i_mul">'<tt>mul</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3743</h4>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3744
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3745<div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3746
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3747<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3748<pre>
Dan Gohman902dfff2009-07-22 22:44:56 +0000[diff] [blame]3749 &lt;result&gt; = mul &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Dan Gohman957b1312009-09-02 17:31:42 +0000[diff] [blame]3750 &lt;result&gt; = mul nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3751 &lt;result&gt; = mul nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3752 &lt;result&gt; = mul nuw nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3753</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3754
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3755<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3756<p>The '<tt>mul</tt>' instruction returns the product of its two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3757
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3758<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3759<p>The two arguments to the '<tt>mul</tt>' instruction must
3760 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3761 integer values. Both arguments must have identical types.</p>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3762
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3763<h5>Semantics:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3764<p>The value produced is the integer product of the two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3765
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3766<p>If the result of the multiplication has unsigned overflow, the result
3767 returned is the mathematical result modulo 2<sup>n</sup>, where n is the bit
3768 width of the result.</p>
3769
3770<p>Because LLVM integers use a two's complement representation, and the result
3771 is the same width as the operands, this instruction returns the correct
3772 result for both signed and unsigned integers. If a full product
3773 (e.g. <tt>i32</tt>x<tt>i32</tt>-><tt>i64</tt>) is needed, the operands should
3774 be sign-extended or zero-extended as appropriate to the width of the full
3775 product.</p>
3776
Dan Gohman902dfff2009-07-22 22:44:56 +0000[diff] [blame]3777<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3778 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3779 <tt>nsw</tt> keywords are present, the result value of the <tt>mul</tt>
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]3780 is a <a href="#trapvalues">trap value</a> if unsigned and/or signed overflow,
3781 respectively, occurs.</p>
Dan Gohmanb07de442009-07-20 22:41:19 +0000[diff] [blame]3782
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3783<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3784<pre>
3785 &lt;result&gt; = mul i32 4, %var <i>; yields {i32}:result = 4 * %var</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3786</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3787
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3788</div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3789
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3790<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3791<h4>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3792 <a name="i_fmul">'<tt>fmul</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3793</h4>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3794
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3795<div>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3796
3797<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3798<pre>
3799 &lt;result&gt; = fmul &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3800</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3801
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3802<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3803<p>The '<tt>fmul</tt>' instruction returns the product of its two operands.</p>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3804
3805<h5>Arguments:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3806<p>The two arguments to the '<tt>fmul</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3807 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3808 floating point values. Both arguments must have identical types.</p>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3809
3810<h5>Semantics:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3811<p>The value produced is the floating point product of the two operands.</p>
3812
3813<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3814<pre>
3815 &lt;result&gt; = fmul float 4.0, %var <i>; yields {float}:result = 4.0 * %var</i>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3816</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3817
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3818</div>
3819
3820<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3821<h4>
3822 <a name="i_udiv">'<tt>udiv</tt>' Instruction</a>
3823</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3824
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3825<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3826
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3827<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3828<pre>
Chris Lattner35315d02011-02-06 21:44:57 +0000[diff] [blame]3829 &lt;result&gt; = udiv &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3830 &lt;result&gt; = udiv exact &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3831</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3832
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3833<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3834<p>The '<tt>udiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3835
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3836<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3837<p>The two arguments to the '<tt>udiv</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3838 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3839 values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3840
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3841<h5>Semantics:</h5>
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3842<p>The value produced is the unsigned integer quotient of the two operands.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3843
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3844<p>Note that unsigned integer division and signed integer division are distinct
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3845 operations; for signed integer division, use '<tt>sdiv</tt>'.</p>
3846
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3847<p>Division by zero leads to undefined behavior.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3848
Chris Lattner35315d02011-02-06 21:44:57 +0000[diff] [blame]3849<p>If the <tt>exact</tt> keyword is present, the result value of the
3850 <tt>udiv</tt> is a <a href="#trapvalues">trap value</a> if %op1 is not a
3851 multiple of %op2 (as such, "((a udiv exact b) mul b) == a").</p>
3852
3853
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3854<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3855<pre>
3856 &lt;result&gt; = udiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3857</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3858
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3859</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3860
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3861<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3862<h4>
3863 <a name="i_sdiv">'<tt>sdiv</tt>' Instruction</a>
3864</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3865
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3866<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3867
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3868<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3869<pre>
Dan Gohmanb07de442009-07-20 22:41:19 +0000[diff] [blame]3870 &lt;result&gt; = sdiv &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Dan Gohman957b1312009-09-02 17:31:42 +0000[diff] [blame]3871 &lt;result&gt; = sdiv exact &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3872</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3873
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3874<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3875<p>The '<tt>sdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3876
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3877<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3878<p>The two arguments to the '<tt>sdiv</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3879 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3880 values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3881
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3882<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3883<p>The value produced is the signed integer quotient of the two operands rounded
3884 towards zero.</p>
3885
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3886<p>Note that signed integer division and unsigned integer division are distinct
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3887 operations; for unsigned integer division, use '<tt>udiv</tt>'.</p>
3888
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3889<p>Division by zero leads to undefined behavior. Overflow also leads to
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3890 undefined behavior; this is a rare case, but can occur, for example, by doing
3891 a 32-bit division of -2147483648 by -1.</p>
3892
Dan Gohman71dfd782009-07-22 00:04:19 +0000[diff] [blame]3893<p>If the <tt>exact</tt> keyword is present, the result value of the
Dan Gohman57255802010-04-23 15:23:32 +0000[diff] [blame]3894 <tt>sdiv</tt> is a <a href="#trapvalues">trap value</a> if the result would
Dan Gohmane501ff72010-07-11 00:08:34 +0000[diff] [blame]3895 be rounded.</p>
Dan Gohmanb07de442009-07-20 22:41:19 +0000[diff] [blame]3896
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3897<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3898<pre>
3899 &lt;result&gt; = sdiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3900</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3901
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3902</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3903
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3904<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3905<h4>
3906 <a name="i_fdiv">'<tt>fdiv</tt>' Instruction</a>
3907</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3908
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3909<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3910
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3911<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3912<pre>
Gabor Greif0f75ad02008-08-07 21:46:00 +0000[diff] [blame]3913 &lt;result&gt; = fdiv &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3914</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3915
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3916<h5>Overview:</h5>
3917<p>The '<tt>fdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3918
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3919<h5>Arguments:</h5>
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]3920<p>The two arguments to the '<tt>fdiv</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3921 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3922 floating point values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3923
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3924<h5>Semantics:</h5>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3925<p>The value produced is the floating point quotient of the two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3926
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3927<h5>Example:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3928<pre>
3929 &lt;result&gt; = fdiv float 4.0, %var <i>; yields {float}:result = 4.0 / %var</i>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3930</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3931
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3932</div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3933
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3934<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3935<h4>
3936 <a name="i_urem">'<tt>urem</tt>' Instruction</a>
3937</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3938
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3939<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3940
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3941<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3942<pre>
3943 &lt;result&gt; = urem &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3944</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3945
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3946<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3947<p>The '<tt>urem</tt>' instruction returns the remainder from the unsigned
3948 division of its two arguments.</p>
3949
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3950<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3951<p>The two arguments to the '<tt>urem</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3952 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3953 values. Both arguments must have identical types.</p>
3954
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3955<h5>Semantics:</h5>
3956<p>This instruction returns the unsigned integer <i>remainder</i> of a division.
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3957 This instruction always performs an unsigned division to get the
3958 remainder.</p>
3959
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3960<p>Note that unsigned integer remainder and signed integer remainder are
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3961 distinct operations; for signed integer remainder, use '<tt>srem</tt>'.</p>
3962
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3963<p>Taking the remainder of a division by zero leads to undefined behavior.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3964
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3965<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3966<pre>
3967 &lt;result&gt; = urem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3968</pre>
3969
3970</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3971
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3972<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3973<h4>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3974 <a name="i_srem">'<tt>srem</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3975</h4>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3976
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3977<div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3978
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3979<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3980<pre>
Gabor Greif0f75ad02008-08-07 21:46:00 +0000[diff] [blame]3981 &lt;result&gt; = srem &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3982</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3983
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3984<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3985<p>The '<tt>srem</tt>' instruction returns the remainder from the signed
3986 division of its two operands. This instruction can also take
3987 <a href="#t_vector">vector</a> versions of the values in which case the
3988 elements must be integers.</p>
Chris Lattnerb8f816e2008-01-04 04:33:49 +0000[diff] [blame]3989
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3990<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3991<p>The two arguments to the '<tt>srem</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3992 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3993 values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3994
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3995<h5>Semantics:</h5>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3996<p>This instruction returns the <i>remainder</i> of a division (where the result
Duncan Sands2769c6e2011-03-07 09:12:24 +0000[diff] [blame]3997 is either zero or has the same sign as the dividend, <tt>op1</tt>), not the
3998 <i>modulo</i> operator (where the result is either zero or has the same sign
3999 as the divisor, <tt>op2</tt>) of a value.
4000 For more information about the difference,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4001 see <a href="http://mathforum.org/dr.math/problems/anne.4.28.99.html">The
4002 Math Forum</a>. For a table of how this is implemented in various languages,
4003 please see <a href="http://en.wikipedia.org/wiki/Modulo_operation">
4004 Wikipedia: modulo operation</a>.</p>
4005
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]4006<p>Note that signed integer remainder and unsigned integer remainder are
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4007 distinct operations; for unsigned integer remainder, use '<tt>urem</tt>'.</p>
4008
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]4009<p>Taking the remainder of a division by zero leads to undefined behavior.
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4010 Overflow also leads to undefined behavior; this is a rare case, but can
4011 occur, for example, by taking the remainder of a 32-bit division of
4012 -2147483648 by -1. (The remainder doesn't actually overflow, but this rule
4013 lets srem be implemented using instructions that return both the result of
4014 the division and the remainder.)</p>
4015
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]4016<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4017<pre>
4018 &lt;result&gt; = srem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]4019</pre>
4020
4021</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4022
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]4023<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4024<h4>
4025 <a name="i_frem">'<tt>frem</tt>' Instruction</a>
4026</h4>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4027
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4028<div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4029
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]4030<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4031<pre>
4032 &lt;result&gt; = frem &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]4033</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4034
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]4035<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4036<p>The '<tt>frem</tt>' instruction returns the remainder from the division of
4037 its two operands.</p>
4038
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]4039<h5>Arguments:</h5>
4040<p>The two arguments to the '<tt>frem</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4041 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
4042 floating point values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4043
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]4044<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4045<p>This instruction returns the <i>remainder</i> of a division. The remainder
4046 has the same sign as the dividend.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4047
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]4048<h5>Example:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4049<pre>
4050 &lt;result&gt; = frem float 4.0, %var <i>; yields {float}:result = 4.0 % %var</i>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]4051</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4052
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4053</div>
Robert Bocchino820bc75b2006-02-17 21:18:08 +0000[diff] [blame]4054
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4055</div>
4056
Reid Spencer2ab01932007-02-02 13:57:07 +0000[diff] [blame]4057<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4058<h3>
4059 <a name="bitwiseops">Bitwise Binary Operations</a>
4060</h3>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4061
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4062<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4063
4064<p>Bitwise binary operators are used to do various forms of bit-twiddling in a
4065 program. They are generally very efficient instructions and can commonly be
4066 strength reduced from other instructions. They require two operands of the
4067 same type, execute an operation on them, and produce a single value. The
4068 resulting value is the same type as its operands.</p>
4069
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4070<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4071<h4>
4072 <a name="i_shl">'<tt>shl</tt>' Instruction</a>
4073</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4074
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4075<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4076
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4077<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4078<pre>
Chris Lattnera676c0f2011-02-07 16:40:21 +0000[diff] [blame]4079 &lt;result&gt; = shl &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
4080 &lt;result&gt; = shl nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
4081 &lt;result&gt; = shl nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
4082 &lt;result&gt; = shl nuw nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4083</pre>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]4084
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4085<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4086<p>The '<tt>shl</tt>' instruction returns the first operand shifted to the left
4087 a specified number of bits.</p>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]4088
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4089<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4090<p>Both arguments to the '<tt>shl</tt>' instruction must be the
4091 same <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
4092 integer type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4093
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4094<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4095<p>The value produced is <tt>op1</tt> * 2<sup><tt>op2</tt></sup> mod
4096 2<sup>n</sup>, where <tt>n</tt> is the width of the result. If <tt>op2</tt>
4097 is (statically or dynamically) negative or equal to or larger than the number
4098 of bits in <tt>op1</tt>, the result is undefined. If the arguments are
4099 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
4100 shift amount in <tt>op2</tt>.</p>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]4101
Chris Lattnera676c0f2011-02-07 16:40:21 +0000[diff] [blame]4102<p>If the <tt>nuw</tt> keyword is present, then the shift produces a
4103 <a href="#trapvalues">trap value</a> if it shifts out any non-zero bits. If
Chris Lattnerf10dfdc2011-02-09 16:44:44 +0000[diff] [blame]4104 the <tt>nsw</tt> keyword is present, then the shift produces a
Chris Lattnera676c0f2011-02-07 16:40:21 +0000[diff] [blame]4105 <a href="#trapvalues">trap value</a> if it shifts out any bits that disagree
4106 with the resultant sign bit. As such, NUW/NSW have the same semantics as
4107 they would if the shift were expressed as a mul instruction with the same
4108 nsw/nuw bits in (mul %op1, (shl 1, %op2)).</p>
4109
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4110<h5>Example:</h5>
4111<pre>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4112 &lt;result&gt; = shl i32 4, %var <i>; yields {i32}: 4 &lt;&lt; %var</i>
4113 &lt;result&gt; = shl i32 4, 2 <i>; yields {i32}: 16</i>
4114 &lt;result&gt; = shl i32 1, 10 <i>; yields {i32}: 1024</i>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]4115 &lt;result&gt; = shl i32 1, 32 <i>; undefined</i>
Mon P Wang4dd832d2008-12-09 05:46:39 +0000[diff] [blame]4116 &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 Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4117</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4118
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4119</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4120
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4121<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4122<h4>
4123 <a name="i_lshr">'<tt>lshr</tt>' Instruction</a>
4124</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4125
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4126<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4127
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4128<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4129<pre>
Chris Lattnera676c0f2011-02-07 16:40:21 +0000[diff] [blame]4130 &lt;result&gt; = lshr &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
4131 &lt;result&gt; = lshr exact &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4132</pre>
4133
4134<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4135<p>The '<tt>lshr</tt>' instruction (logical shift right) returns the first
4136 operand shifted to the right a specified number of bits with zero fill.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4137
4138<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4139<p>Both arguments to the '<tt>lshr</tt>' instruction must be the same
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4140 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
4141 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4142
4143<h5>Semantics:</h5>
4144<p>This instruction always performs a logical shift right operation. The most
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4145 significant bits of the result will be filled with zero bits after the shift.
4146 If <tt>op2</tt> is (statically or dynamically) equal to or larger than the
4147 number of bits in <tt>op1</tt>, the result is undefined. If the arguments are
4148 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
4149 shift amount in <tt>op2</tt>.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4150
Chris Lattnera676c0f2011-02-07 16:40:21 +0000[diff] [blame]4151<p>If the <tt>exact</tt> keyword is present, the result value of the
4152 <tt>lshr</tt> is a <a href="#trapvalues">trap value</a> if any of the bits
4153 shifted out are non-zero.</p>
4154
4155
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4156<h5>Example:</h5>
4157<pre>
4158 &lt;result&gt; = lshr i32 4, 1 <i>; yields {i32}:result = 2</i>
4159 &lt;result&gt; = lshr i32 4, 2 <i>; yields {i32}:result = 1</i>
4160 &lt;result&gt; = lshr i8 4, 3 <i>; yields {i8}:result = 0</i>
4161 &lt;result&gt; = lshr i8 -2, 1 <i>; yields {i8}:result = 0x7FFFFFFF </i>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]4162 &lt;result&gt; = lshr i32 1, 32 <i>; undefined</i>
Mon P Wang4dd832d2008-12-09 05:46:39 +0000[diff] [blame]4163 &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 Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4164</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4165
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4166</div>
4167
Reid Spencer2ab01932007-02-02 13:57:07 +0000[diff] [blame]4168<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4169<h4>
4170 <a name="i_ashr">'<tt>ashr</tt>' Instruction</a>
4171</h4>
4172
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4173<div>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4174
4175<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4176<pre>
Chris Lattnera676c0f2011-02-07 16:40:21 +0000[diff] [blame]4177 &lt;result&gt; = ashr &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
4178 &lt;result&gt; = ashr exact &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4179</pre>
4180
4181<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4182<p>The '<tt>ashr</tt>' instruction (arithmetic shift right) returns the first
4183 operand shifted to the right a specified number of bits with sign
4184 extension.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4185
4186<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4187<p>Both arguments to the '<tt>ashr</tt>' instruction must be the same
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4188 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
4189 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4190
4191<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4192<p>This instruction always performs an arithmetic shift right operation, The
4193 most significant bits of the result will be filled with the sign bit
4194 of <tt>op1</tt>. If <tt>op2</tt> is (statically or dynamically) equal to or
4195 larger than the number of bits in <tt>op1</tt>, the result is undefined. If
4196 the arguments are vectors, each vector element of <tt>op1</tt> is shifted by
4197 the corresponding shift amount in <tt>op2</tt>.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4198
Chris Lattnera676c0f2011-02-07 16:40:21 +0000[diff] [blame]4199<p>If the <tt>exact</tt> keyword is present, the result value of the
4200 <tt>ashr</tt> is a <a href="#trapvalues">trap value</a> if any of the bits
4201 shifted out are non-zero.</p>
4202
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4203<h5>Example:</h5>
4204<pre>
4205 &lt;result&gt; = ashr i32 4, 1 <i>; yields {i32}:result = 2</i>
4206 &lt;result&gt; = ashr i32 4, 2 <i>; yields {i32}:result = 1</i>
4207 &lt;result&gt; = ashr i8 4, 3 <i>; yields {i8}:result = 0</i>
4208 &lt;result&gt; = ashr i8 -2, 1 <i>; yields {i8}:result = -1</i>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]4209 &lt;result&gt; = ashr i32 1, 32 <i>; undefined</i>
Mon P Wang4dd832d2008-12-09 05:46:39 +0000[diff] [blame]4210 &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 Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4211</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4212
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4213</div>
4214
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4215<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4216<h4>
4217 <a name="i_and">'<tt>and</tt>' Instruction</a>
4218</h4>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4219
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4220<div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4221
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4222<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4223<pre>
Gabor Greif0f75ad02008-08-07 21:46:00 +0000[diff] [blame]4224 &lt;result&gt; = and &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4225</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4226
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4227<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4228<p>The '<tt>and</tt>' instruction returns the bitwise logical and of its two
4229 operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4230
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4231<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4232<p>The two arguments to the '<tt>and</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4233 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
4234 values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4235
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4236<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4237<p>The truth table used for the '<tt>and</tt>' instruction is:</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4238
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4239<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]4240 <tbody>
4241 <tr>
4242 <td>In0</td>
4243 <td>In1</td>
4244 <td>Out</td>
4245 </tr>
4246 <tr>
4247 <td>0</td>
4248 <td>0</td>
4249 <td>0</td>
4250 </tr>
4251 <tr>
4252 <td>0</td>
4253 <td>1</td>
4254 <td>0</td>
4255 </tr>
4256 <tr>
4257 <td>1</td>
4258 <td>0</td>
4259 <td>0</td>
4260 </tr>
4261 <tr>
4262 <td>1</td>
4263 <td>1</td>
4264 <td>1</td>
4265 </tr>
4266 </tbody>
4267</table>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4268
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4269<h5>Example:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4270<pre>
4271 &lt;result&gt; = and i32 4, %var <i>; yields {i32}:result = 4 &amp; %var</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4272 &lt;result&gt; = and i32 15, 40 <i>; yields {i32}:result = 8</i>
4273 &lt;result&gt; = and i32 4, 8 <i>; yields {i32}:result = 0</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4274</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4275</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4276<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4277<h4>
4278 <a name="i_or">'<tt>or</tt>' Instruction</a>
4279</h4>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4280
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4281<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4282
4283<h5>Syntax:</h5>
4284<pre>
4285 &lt;result&gt; = or &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
4286</pre>
4287
4288<h5>Overview:</h5>
4289<p>The '<tt>or</tt>' instruction returns the bitwise logical inclusive or of its
4290 two operands.</p>
4291
4292<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4293<p>The two arguments to the '<tt>or</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4294 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
4295 values. Both arguments must have identical types.</p>
4296
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4297<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4298<p>The truth table used for the '<tt>or</tt>' instruction is:</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4299
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]4300<table border="1" cellspacing="0" cellpadding="4">
4301 <tbody>
4302 <tr>
4303 <td>In0</td>
4304 <td>In1</td>
4305 <td>Out</td>
4306 </tr>
4307 <tr>
4308 <td>0</td>
4309 <td>0</td>
4310 <td>0</td>
4311 </tr>
4312 <tr>
4313 <td>0</td>
4314 <td>1</td>
4315 <td>1</td>
4316 </tr>
4317 <tr>
4318 <td>1</td>
4319 <td>0</td>
4320 <td>1</td>
4321 </tr>
4322 <tr>
4323 <td>1</td>
4324 <td>1</td>
4325 <td>1</td>
4326 </tr>
4327 </tbody>
4328</table>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4329
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4330<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4331<pre>
4332 &lt;result&gt; = or i32 4, %var <i>; yields {i32}:result = 4 | %var</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4333 &lt;result&gt; = or i32 15, 40 <i>; yields {i32}:result = 47</i>
4334 &lt;result&gt; = or i32 4, 8 <i>; yields {i32}:result = 12</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4335</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4336
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4337</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4338
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4339<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4340<h4>
4341 <a name="i_xor">'<tt>xor</tt>' Instruction</a>
4342</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4343
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4344<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4345
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4346<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4347<pre>
4348 &lt;result&gt; = xor &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4349</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4350
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4351<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4352<p>The '<tt>xor</tt>' instruction returns the bitwise logical exclusive or of
4353 its two operands. The <tt>xor</tt> is used to implement the "one's
4354 complement" operation, which is the "~" operator in C.</p>
4355
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4356<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4357<p>The two arguments to the '<tt>xor</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4358 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
4359 values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4360
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4361<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4362<p>The truth table used for the '<tt>xor</tt>' instruction is:</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4363
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]4364<table border="1" cellspacing="0" cellpadding="4">
4365 <tbody>
4366 <tr>
4367 <td>In0</td>
4368 <td>In1</td>
4369 <td>Out</td>
4370 </tr>
4371 <tr>
4372 <td>0</td>
4373 <td>0</td>
4374 <td>0</td>
4375 </tr>
4376 <tr>
4377 <td>0</td>
4378 <td>1</td>
4379 <td>1</td>
4380 </tr>
4381 <tr>
4382 <td>1</td>
4383 <td>0</td>
4384 <td>1</td>
4385 </tr>
4386 <tr>
4387 <td>1</td>
4388 <td>1</td>
4389 <td>0</td>
4390 </tr>
4391 </tbody>
4392</table>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4393
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4394<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4395<pre>
4396 &lt;result&gt; = xor i32 4, %var <i>; yields {i32}:result = 4 ^ %var</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4397 &lt;result&gt; = xor i32 15, 40 <i>; yields {i32}:result = 39</i>
4398 &lt;result&gt; = xor i32 4, 8 <i>; yields {i32}:result = 12</i>
4399 &lt;result&gt; = xor i32 %V, -1 <i>; yields {i32}:result = ~%V</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4400</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4401
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4402</div>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4403
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4404</div>
4405
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4406<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4407<h3>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4408 <a name="vectorops">Vector Operations</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4409</h3>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4410
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4411<div>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4412
4413<p>LLVM supports several instructions to represent vector operations in a
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4414 target-independent manner. These instructions cover the element-access and
4415 vector-specific operations needed to process vectors effectively. While LLVM
4416 does directly support these vector operations, many sophisticated algorithms
4417 will want to use target-specific intrinsics to take full advantage of a
4418 specific target.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4419
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4420<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4421<h4>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4422 <a name="i_extractelement">'<tt>extractelement</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4423</h4>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4424
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4425<div>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4426
4427<h5>Syntax:</h5>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4428<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4429 &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 Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4430</pre>
4431
4432<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4433<p>The '<tt>extractelement</tt>' instruction extracts a single scalar element
4434 from a vector at a specified index.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4435
4436
4437<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4438<p>The first operand of an '<tt>extractelement</tt>' instruction is a value
4439 of <a href="#t_vector">vector</a> type. The second operand is an index
4440 indicating the position from which to extract the element. The index may be
4441 a variable.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4442
4443<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4444<p>The result is a scalar of the same type as the element type of
4445 <tt>val</tt>. Its value is the value at position <tt>idx</tt> of
4446 <tt>val</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
4447 results are undefined.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4448
4449<h5>Example:</h5>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4450<pre>
Gabor Greif03ab4dc2009-10-28 13:14:50 +0000[diff] [blame]4451 &lt;result&gt; = extractelement &lt;4 x i32&gt; %vec, i32 0 <i>; yields i32</i>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4452</pre>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4453
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4454</div>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4455
4456<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4457<h4>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4458 <a name="i_insertelement">'<tt>insertelement</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4459</h4>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4460
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4461<div>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4462
4463<h5>Syntax:</h5>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4464<pre>
Dan Gohman43ba0672008-05-12 23:38:42 +0000[diff] [blame]4465 &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 Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4466</pre>
4467
4468<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4469<p>The '<tt>insertelement</tt>' instruction inserts a scalar element into a
4470 vector at a specified index.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4471
4472<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4473<p>The first operand of an '<tt>insertelement</tt>' instruction is a value
4474 of <a href="#t_vector">vector</a> type. The second operand is a scalar value
4475 whose type must equal the element type of the first operand. The third
4476 operand is an index indicating the position at which to insert the value.
4477 The index may be a variable.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4478
4479<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4480<p>The result is a vector of the same type as <tt>val</tt>. Its element values
4481 are those of <tt>val</tt> except at position <tt>idx</tt>, where it gets the
4482 value <tt>elt</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
4483 results are undefined.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4484
4485<h5>Example:</h5>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4486<pre>
Gabor Greif03ab4dc2009-10-28 13:14:50 +0000[diff] [blame]4487 &lt;result&gt; = insertelement &lt;4 x i32&gt; %vec, i32 1, i32 0 <i>; yields &lt;4 x i32&gt;</i>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4488</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4489
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4490</div>
4491
4492<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4493<h4>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4494 <a name="i_shufflevector">'<tt>shufflevector</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4495</h4>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4496
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4497<div>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4498
4499<h5>Syntax:</h5>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4500<pre>
Mon P Wang25f01062008-11-10 04:46:22 +0000[diff] [blame]4501 &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 Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4502</pre>
4503
4504<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4505<p>The '<tt>shufflevector</tt>' instruction constructs a permutation of elements
4506 from two input vectors, returning a vector with the same element type as the
4507 input and length that is the same as the shuffle mask.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4508
4509<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4510<p>The first two operands of a '<tt>shufflevector</tt>' instruction are vectors
4511 with types that match each other. The third argument is a shuffle mask whose
4512 element type is always 'i32'. The result of the instruction is a vector
4513 whose length is the same as the shuffle mask and whose element type is the
4514 same as the element type of the first two operands.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4515
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4516<p>The shuffle mask operand is required to be a constant vector with either
4517 constant integer or undef values.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4518
4519<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4520<p>The elements of the two input vectors are numbered from left to right across
4521 both of the vectors. The shuffle mask operand specifies, for each element of
4522 the result vector, which element of the two input vectors the result element
4523 gets. The element selector may be undef (meaning "don't care") and the
4524 second operand may be undef if performing a shuffle from only one vector.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4525
4526<h5>Example:</h5>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4527<pre>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4528 &lt;result&gt; = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; %v2,
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]4529 &lt;4 x i32&gt; &lt;i32 0, i32 4, i32 1, i32 5&gt; <i>; yields &lt;4 x i32&gt;</i>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4530 &lt;result&gt; = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; undef,
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4531 &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 Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4532 &lt;result&gt; = shufflevector &lt;8 x i32&gt; %v1, &lt;8 x i32&gt; undef,
Mon P Wang25f01062008-11-10 04:46:22 +0000[diff] [blame]4533 &lt;4 x i32&gt; &lt;i32 0, i32 1, i32 2, i32 3&gt; <i>; yields &lt;4 x i32&gt;</i>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4534 &lt;result&gt; = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; %v2,
Mon P Wang25f01062008-11-10 04:46:22 +0000[diff] [blame]4535 &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 Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4536</pre>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4537
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4538</div>
Tanya Lattnerb138bbe2006-04-14 19:24:33 +0000[diff] [blame]4539
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4540</div>
4541
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4542<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4543<h3>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4544 <a name="aggregateops">Aggregate Operations</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4545</h3>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4546
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4547<div>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4548
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]4549<p>LLVM supports several instructions for working with
4550 <a href="#t_aggregate">aggregate</a> values.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4551
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4552<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4553<h4>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4554 <a name="i_extractvalue">'<tt>extractvalue</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4555</h4>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4556
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4557<div>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4558
4559<h5>Syntax:</h5>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4560<pre>
4561 &lt;result&gt; = extractvalue &lt;aggregate type&gt; &lt;val&gt;, &lt;idx&gt;{, &lt;idx&gt;}*
4562</pre>
4563
4564<h5>Overview:</h5>
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]4565<p>The '<tt>extractvalue</tt>' instruction extracts the value of a member field
4566 from an <a href="#t_aggregate">aggregate</a> value.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4567
4568<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4569<p>The first operand of an '<tt>extractvalue</tt>' instruction is a value
Chris Lattner13ee7952010-08-28 04:09:24 +0000[diff] [blame]4570 of <a href="#t_struct">struct</a> or
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]4571 <a href="#t_array">array</a> type. The operands are constant indices to
4572 specify which value to extract in a similar manner as indices in a
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4573 '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
Frits van Bommel7cf63ac2010-12-05 20:54:38 +0000[diff] [blame]4574 <p>The major differences to <tt>getelementptr</tt> indexing are:</p>
4575 <ul>
4576 <li>Since the value being indexed is not a pointer, the first index is
4577 omitted and assumed to be zero.</li>
4578 <li>At least one index must be specified.</li>
4579 <li>Not only struct indices but also array indices must be in
4580 bounds.</li>
4581 </ul>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4582
4583<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4584<p>The result is the value at the position in the aggregate specified by the
4585 index operands.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4586
4587<h5>Example:</h5>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4588<pre>
Gabor Greif03ab4dc2009-10-28 13:14:50 +0000[diff] [blame]4589 &lt;result&gt; = extractvalue {i32, float} %agg, 0 <i>; yields i32</i>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4590</pre>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4591
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4592</div>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4593
4594<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4595<h4>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4596 <a name="i_insertvalue">'<tt>insertvalue</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4597</h4>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4598
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4599<div>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4600
4601<h5>Syntax:</h5>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4602<pre>
Bill Wendlingf6a91cf2011-07-26 20:42:28 +0000[diff] [blame]4603 &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 Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4604</pre>
4605
4606<h5>Overview:</h5>
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]4607<p>The '<tt>insertvalue</tt>' instruction inserts a value into a member field
4608 in an <a href="#t_aggregate">aggregate</a> value.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4609
4610<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4611<p>The first operand of an '<tt>insertvalue</tt>' instruction is a value
Chris Lattner13ee7952010-08-28 04:09:24 +0000[diff] [blame]4612 of <a href="#t_struct">struct</a> or
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]4613 <a href="#t_array">array</a> type. The second operand is a first-class
4614 value to insert. The following operands are constant indices indicating
4615 the position at which to insert the value in a similar manner as indices in a
Frits van Bommel7cf63ac2010-12-05 20:54:38 +0000[diff] [blame]4616 '<tt><a href="#i_extractvalue">extractvalue</a></tt>' instruction. The
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4617 value to insert must have the same type as the value identified by the
4618 indices.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4619
4620<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4621<p>The result is an aggregate of the same type as <tt>val</tt>. Its value is
4622 that of <tt>val</tt> except that the value at the position specified by the
4623 indices is that of <tt>elt</tt>.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4624
4625<h5>Example:</h5>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4626<pre>
Chris Lattnerc2e85402011-05-22 07:18:08 +0000[diff] [blame]4627 %agg1 = insertvalue {i32, float} undef, i32 1, 0 <i>; yields {i32 1, float undef}</i>
4628 %agg2 = insertvalue {i32, float} %agg1, float %val, 1 <i>; yields {i32 1, float %val}</i>
4629 %agg3 = insertvalue {i32, {float}} %agg1, float %val, 1, 0 <i>; yields {i32 1, float %val}</i>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4630</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4631
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4632</div>
4633
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4634</div>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4635
4636<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4637<h3>
Chris Lattner6ab66722006-08-15 00:45:58 +0000[diff] [blame]4638 <a name="memoryops">Memory Access and Addressing Operations</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4639</h3>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4640
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4641<div>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4642
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4643<p>A key design point of an SSA-based representation is how it represents
4644 memory. In LLVM, no memory locations are in SSA form, which makes things
Victor Hernandeza70c6df2009-10-26 23:44:29 +0000[diff] [blame]4645 very simple. This section describes how to read, write, and allocate
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4646 memory in LLVM.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4647
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4648<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4649<h4>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4650 <a name="i_alloca">'<tt>alloca</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4651</h4>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4652
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4653<div>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4654
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4655<h5>Syntax:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4656<pre>
Dan Gohman2140a742010-05-28 01:14:11 +0000[diff] [blame]4657 &lt;result&gt; = alloca &lt;type&gt;[, &lt;ty&gt; &lt;NumElements&gt;][, align &lt;alignment&gt;] <i>; yields {type*}:result</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4658</pre>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4659
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4660<h5>Overview:</h5>
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]4661<p>The '<tt>alloca</tt>' instruction allocates memory on the stack frame of the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4662 currently executing function, to be automatically released when this function
4663 returns to its caller. The object is always allocated in the generic address
4664 space (address space zero).</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4665
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4666<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4667<p>The '<tt>alloca</tt>' instruction
4668 allocates <tt>sizeof(&lt;type&gt;)*NumElements</tt> bytes of memory on the
4669 runtime stack, returning a pointer of the appropriate type to the program.
4670 If "NumElements" is specified, it is the number of elements allocated,
4671 otherwise "NumElements" is defaulted to be one. If a constant alignment is
4672 specified, the value result of the allocation is guaranteed to be aligned to
4673 at least that boundary. If not specified, or if zero, the target can choose
4674 to align the allocation on any convenient boundary compatible with the
4675 type.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4676
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4677<p>'<tt>type</tt>' may be any sized type.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4678
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4679<h5>Semantics:</h5>
Bill Wendling9ee6a312009-05-08 20:49:29 +0000[diff] [blame]4680<p>Memory is allocated; a pointer is returned. The operation is undefined if
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4681 there is insufficient stack space for the allocation. '<tt>alloca</tt>'d
4682 memory is automatically released when the function returns. The
4683 '<tt>alloca</tt>' instruction is commonly used to represent automatic
4684 variables that must have an address available. When the function returns
4685 (either with the <tt><a href="#i_ret">ret</a></tt>
4686 or <tt><a href="#i_unwind">unwind</a></tt> instructions), the memory is
4687 reclaimed. Allocating zero bytes is legal, but the result is undefined.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4688
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4689<h5>Example:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4690<pre>
Dan Gohman7a5acb52009-01-04 23:49:44 +0000[diff] [blame]4691 %ptr = alloca i32 <i>; yields {i32*}:ptr</i>
4692 %ptr = alloca i32, i32 4 <i>; yields {i32*}:ptr</i>
4693 %ptr = alloca i32, i32 4, align 1024 <i>; yields {i32*}:ptr</i>
4694 %ptr = alloca i32, align 1024 <i>; yields {i32*}:ptr</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4695</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4696
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4697</div>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4698
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4699<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4700<h4>
4701 <a name="i_load">'<tt>load</tt>' Instruction</a>
4702</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4703
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4704<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4705
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4706<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4707<pre>
Eli Friedman02e737b2011-08-12 22:50:01 +0000[diff] [blame]4708 &lt;result&gt; = load [volatile] &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;][, !nontemporal !&lt;index&gt;]
4709 &lt;result&gt; = load atomic [volatile] &lt;ty&gt;* &lt;pointer&gt; [singlethread] &lt;ordering&gt;, align &lt;alignment&gt;
Bill Wendlingbc4024f2010-02-25 21:23:24 +0000[diff] [blame]4710 !&lt;index&gt; = !{ i32 1 }
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4711</pre>
4712
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4713<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4714<p>The '<tt>load</tt>' instruction is used to read from memory.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4715
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4716<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4717<p>The argument to the '<tt>load</tt>' instruction specifies the memory address
4718 from which to load. The pointer must point to
4719 a <a href="#t_firstclass">first class</a> type. If the <tt>load</tt> is
4720 marked as <tt>volatile</tt>, then the optimizer is not allowed to modify the
Jeffrey Yasskin5d284ae2010-04-26 21:21:24 +0000[diff] [blame]4721 number or order of execution of this <tt>load</tt> with other <a
4722 href="#volatile">volatile operations</a>.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4723
Eli Friedman59b66882011-08-09 23:02:53 +0000[diff] [blame]4724<p>If the <code>load</code> is marked as <code>atomic</code>, it takes an extra
4725 <a href="#ordering">ordering</a> and optional <code>singlethread</code>
4726 argument. The <code>release</code> and <code>acq_rel</code> orderings are
4727 not valid on <code>load</code> instructions. Atomic loads produce <a
4728 href="#memorymodel">defined</a> results when they may see multiple atomic
4729 stores. The type of the pointee must be an integer type whose bit width
4730 is a power of two greater than or equal to eight and less than or equal
4731 to a target-specific size limit. <code>align</code> must be explicitly
4732 specified on atomic loads, and the load has undefined behavior if the
4733 alignment is not set to a value which is at least the size in bytes of
4734 the pointee. <code>!nontemporal</code> does not have any defined semantics
4735 for atomic loads.</p>
4736
Bill Wendlingbc4024f2010-02-25 21:23:24 +0000[diff] [blame]4737<p>The optional constant <tt>align</tt> argument specifies the alignment of the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4738 operation (that is, the alignment of the memory address). A value of 0 or an
Bill Wendlingbc4024f2010-02-25 21:23:24 +0000[diff] [blame]4739 omitted <tt>align</tt> argument means that the operation has the preferential
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4740 alignment for the target. It is the responsibility of the code emitter to
4741 ensure that the alignment information is correct. Overestimating the
Bill Wendlingbc4024f2010-02-25 21:23:24 +0000[diff] [blame]4742 alignment results in undefined behavior. Underestimating the alignment may
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4743 produce less efficient code. An alignment of 1 is always safe.</p>
4744
Bill Wendlingbc4024f2010-02-25 21:23:24 +0000[diff] [blame]4745<p>The optional <tt>!nontemporal</tt> metadata must reference a single
4746 metatadata name &lt;index&gt; corresponding to a metadata node with
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]4747 one <tt>i32</tt> entry of value 1. The existence of
Bill Wendlingbc4024f2010-02-25 21:23:24 +0000[diff] [blame]4748 the <tt>!nontemporal</tt> metatadata on the instruction tells the optimizer
4749 and code generator that this load is not expected to be reused in the cache.
4750 The code generator may select special instructions to save cache bandwidth,
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]4751 such as the <tt>MOVNT</tt> instruction on x86.</p>
David Greene9641d062010-02-16 20:50:18 +0000[diff] [blame]4752
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4753<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4754<p>The location of memory pointed to is loaded. If the value being loaded is of
4755 scalar type then the number of bytes read does not exceed the minimum number
4756 of bytes needed to hold all bits of the type. For example, loading an
4757 <tt>i24</tt> reads at most three bytes. When loading a value of a type like
4758 <tt>i20</tt> with a size that is not an integral number of bytes, the result
4759 is undefined if the value was not originally written using a store of the
4760 same type.</p>
4761
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4762<h5>Examples:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4763<pre>
4764 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
4765 <a href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4766 %val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4767</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4768
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4769</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4770
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4771<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4772<h4>
4773 <a name="i_store">'<tt>store</tt>' Instruction</a>
4774</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4775
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4776<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4777
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4778<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4779<pre>
Eli Friedman02e737b2011-08-12 22:50:01 +0000[diff] [blame]4780 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>
4781 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 Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4782</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4783
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4784<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4785<p>The '<tt>store</tt>' instruction is used to write to memory.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4786
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4787<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4788<p>There are two arguments to the '<tt>store</tt>' instruction: a value to store
4789 and an address at which to store it. The type of the
4790 '<tt>&lt;pointer&gt;</tt>' operand must be a pointer to
4791 the <a href="#t_firstclass">first class</a> type of the
Jeffrey Yasskin5d284ae2010-04-26 21:21:24 +0000[diff] [blame]4792 '<tt>&lt;value&gt;</tt>' operand. If the <tt>store</tt> is marked as
4793 <tt>volatile</tt>, then the optimizer is not allowed to modify the number or
4794 order of execution of this <tt>store</tt> with other <a
4795 href="#volatile">volatile operations</a>.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4796
Eli Friedman59b66882011-08-09 23:02:53 +0000[diff] [blame]4797<p>If the <code>store</code> is marked as <code>atomic</code>, it takes an extra
4798 <a href="#ordering">ordering</a> and optional <code>singlethread</code>
4799 argument. The <code>acquire</code> and <code>acq_rel</code> orderings aren't
4800 valid on <code>store</code> instructions. Atomic loads produce <a
4801 href="#memorymodel">defined</a> results when they may see multiple atomic
4802 stores. The type of the pointee must be an integer type whose bit width
4803 is a power of two greater than or equal to eight and less than or equal
4804 to a target-specific size limit. <code>align</code> must be explicitly
4805 specified on atomic stores, and the store has undefined behavior if the
4806 alignment is not set to a value which is at least the size in bytes of
4807 the pointee. <code>!nontemporal</code> does not have any defined semantics
4808 for atomic stores.</p>
4809
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4810<p>The optional constant "align" argument specifies the alignment of the
4811 operation (that is, the alignment of the memory address). A value of 0 or an
4812 omitted "align" argument means that the operation has the preferential
4813 alignment for the target. It is the responsibility of the code emitter to
4814 ensure that the alignment information is correct. Overestimating the
4815 alignment results in an undefined behavior. Underestimating the alignment may
4816 produce less efficient code. An alignment of 1 is always safe.</p>
4817
David Greene9641d062010-02-16 20:50:18 +0000[diff] [blame]4818<p>The optional !nontemporal metadata must reference a single metatadata
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]4819 name &lt;index&gt; corresponding to a metadata node with one i32 entry of
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]4820 value 1. The existence of the !nontemporal metatadata on the
David Greene9641d062010-02-16 20:50:18 +0000[diff] [blame]4821 instruction tells the optimizer and code generator that this load is
4822 not expected to be reused in the cache. The code generator may
4823 select special instructions to save cache bandwidth, such as the
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]4824 MOVNT instruction on x86.</p>
David Greene9641d062010-02-16 20:50:18 +0000[diff] [blame]4825
4826
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]4827<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4828<p>The contents of memory are updated to contain '<tt>&lt;value&gt;</tt>' at the
4829 location specified by the '<tt>&lt;pointer&gt;</tt>' operand. If
4830 '<tt>&lt;value&gt;</tt>' is of scalar type then the number of bytes written
4831 does not exceed the minimum number of bytes needed to hold all bits of the
4832 type. For example, storing an <tt>i24</tt> writes at most three bytes. When
4833 writing a value of a type like <tt>i20</tt> with a size that is not an
4834 integral number of bytes, it is unspecified what happens to the extra bits
4835 that do not belong to the type, but they will typically be overwritten.</p>
4836
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4837<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4838<pre>
4839 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Bill Wendling8830ffe2007-10-22 05:10:05 +0000[diff] [blame]4840 store i32 3, i32* %ptr <i>; yields {void}</i>
4841 %val = <a href="#i_load">load</a> i32* %ptr <i>; yields {i32}:val = i32 3</i>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4842</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4843
Reid Spencer443460a2006-11-09 21:15:49 +0000[diff] [blame]4844</div>
4845
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4846<!-- _______________________________________________________________________ -->
NAKAMURA Takumi0300d882011-08-12 06:17:17 +0000[diff] [blame]4847<h4>
4848<a name="i_fence">'<tt>fence</tt>' Instruction</a>
4849</h4>
Eli Friedmanfee02c62011-07-25 23:16:38 +0000[diff] [blame]4850
NAKAMURA Takumi0300d882011-08-12 06:17:17 +0000[diff] [blame]4851<div>
Eli Friedmanfee02c62011-07-25 23:16:38 +0000[diff] [blame]4852
4853<h5>Syntax:</h5>
4854<pre>
4855 fence [singlethread] &lt;ordering&gt; <i>; yields {void}</i>
4856</pre>
4857
4858<h5>Overview:</h5>
4859<p>The '<tt>fence</tt>' instruction is used to introduce happens-before edges
4860between operations.</p>
4861
4862<h5>Arguments:</h5> <p>'<code>fence</code>' instructions take an <a
4863href="#ordering">ordering</a> argument which defines what
4864<i>synchronizes-with</i> edges they add. They can only be given
4865<code>acquire</code>, <code>release</code>, <code>acq_rel</code>, and
4866<code>seq_cst</code> orderings.</p>
4867
4868<h5>Semantics:</h5>
4869<p>A fence <var>A</var> which has (at least) <code>release</code> ordering
4870semantics <i>synchronizes with</i> a fence <var>B</var> with (at least)
4871<code>acquire</code> ordering semantics if and only if there exist atomic
4872operations <var>X</var> and <var>Y</var>, both operating on some atomic object
4873<var>M</var>, such that <var>A</var> is sequenced before <var>X</var>,
4874<var>X</var> modifies <var>M</var> (either directly or through some side effect
4875of a sequence headed by <var>X</var>), <var>Y</var> is sequenced before
4876<var>B</var>, and <var>Y</var> observes <var>M</var>. This provides a
4877<i>happens-before</i> dependency between <var>A</var> and <var>B</var>. Rather
4878than an explicit <code>fence</code>, one (but not both) of the atomic operations
4879<var>X</var> or <var>Y</var> might provide a <code>release</code> or
4880<code>acquire</code> (resp.) ordering constraint and still
4881<i>synchronize-with</i> the explicit <code>fence</code> and establish the
4882<i>happens-before</i> edge.</p>
4883
4884<p>A <code>fence</code> which has <code>seq_cst</code> ordering, in addition to
4885having both <code>acquire</code> and <code>release</code> semantics specified
4886above, participates in the global program order of other <code>seq_cst</code>
4887operations and/or fences.</p>
4888
4889<p>The optional "<a href="#singlethread"><code>singlethread</code></a>" argument
4890specifies that the fence only synchronizes with other fences in the same
4891thread. (This is useful for interacting with signal handlers.)</p>
4892
Eli Friedmanfee02c62011-07-25 23:16:38 +0000[diff] [blame]4893<h5>Example:</h5>
4894<pre>
4895 fence acquire <i>; yields {void}</i>
4896 fence singlethread seq_cst <i>; yields {void}</i>
4897</pre>
4898
4899</div>
4900
4901<!-- _______________________________________________________________________ -->
NAKAMURA Takumi0300d882011-08-12 06:17:17 +0000[diff] [blame]4902<h4>
4903<a name="i_cmpxchg">'<tt>cmpxchg</tt>' Instruction</a>
4904</h4>
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]4905
NAKAMURA Takumi0300d882011-08-12 06:17:17 +0000[diff] [blame]4906<div>
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]4907
4908<h5>Syntax:</h5>
4909<pre>
Eli Friedman02e737b2011-08-12 22:50:01 +0000[diff] [blame]4910 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 Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]4911</pre>
4912
4913<h5>Overview:</h5>
4914<p>The '<tt>cmpxchg</tt>' instruction is used to atomically modify memory.
4915It loads a value in memory and compares it to a given value. If they are
4916equal, it stores a new value into the memory.</p>
4917
4918<h5>Arguments:</h5>
4919<p>There are three arguments to the '<code>cmpxchg</code>' instruction: an
4920address to operate on, a value to compare to the value currently be at that
4921address, and a new value to place at that address if the compared values are
4922equal. The type of '<var>&lt;cmp&gt;</var>' must be an integer type whose
4923bit width is a power of two greater than or equal to eight and less than
4924or equal to a target-specific size limit. '<var>&lt;cmp&gt;</var>' and
4925'<var>&lt;new&gt;</var>' must have the same type, and the type of
4926'<var>&lt;pointer&gt;</var>' must be a pointer to that type. If the
4927<code>cmpxchg</code> is marked as <code>volatile</code>, then the
4928optimizer is not allowed to modify the number or order of execution
4929of this <code>cmpxchg</code> with other <a href="#volatile">volatile
4930operations</a>.</p>
4931
4932<!-- FIXME: Extend allowed types. -->
4933
4934<p>The <a href="#ordering"><var>ordering</var></a> argument specifies how this
4935<code>cmpxchg</code> synchronizes with other atomic operations.</p>
4936
4937<p>The optional "<code>singlethread</code>" argument declares that the
4938<code>cmpxchg</code> is only atomic with respect to code (usually signal
4939handlers) running in the same thread as the <code>cmpxchg</code>. Otherwise the
4940cmpxchg is atomic with respect to all other code in the system.</p>
4941
4942<p>The pointer passed into cmpxchg must have alignment greater than or equal to
4943the size in memory of the operand.
4944
4945<h5>Semantics:</h5>
4946<p>The contents of memory at the location specified by the
4947'<tt>&lt;pointer&gt;</tt>' operand is read and compared to
4948'<tt>&lt;cmp&gt;</tt>'; if the read value is the equal,
4949'<tt>&lt;new&gt;</tt>' is written. The original value at the location
4950is returned.
4951
4952<p>A successful <code>cmpxchg</code> is a read-modify-write instruction for the
4953purpose of identifying <a href="#release_sequence">release sequences</a>. A
4954failed <code>cmpxchg</code> is equivalent to an atomic load with an ordering
4955parameter determined by dropping any <code>release</code> part of the
4956<code>cmpxchg</code>'s ordering.</p>
4957
4958<!--
4959FIXME: Is compare_exchange_weak() necessary? (Consider after we've done
4960optimization work on ARM.)
4961
4962FIXME: Is a weaker ordering constraint on failure helpful in practice?
4963-->
4964
4965<h5>Example:</h5>
4966<pre>
4967entry:
4968 %orig = atomic <a href="#i_load">load</a> i32* %ptr unordered <i>; yields {i32}</i>
4969 <a href="#i_br">br</a> label %loop
4970
4971loop:
4972 %cmp = <a href="#i_phi">phi</a> i32 [ %orig, %entry ], [%old, %loop]
4973 %squared = <a href="#i_mul">mul</a> i32 %cmp, %cmp
4974 %old = cmpxchg i32* %ptr, i32 %cmp, i32 %squared <i>; yields {i32}</i>
4975 %success = <a href="#i_icmp">icmp</a> eq i32 %cmp, %old
4976 <a href="#i_br">br</a> i1 %success, label %done, label %loop
4977
4978done:
4979 ...
4980</pre>
4981
4982</div>
4983
4984<!-- _______________________________________________________________________ -->
NAKAMURA Takumi0300d882011-08-12 06:17:17 +0000[diff] [blame]4985<h4>
4986<a name="i_atomicrmw">'<tt>atomicrmw</tt>' Instruction</a>
4987</h4>
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]4988
NAKAMURA Takumi0300d882011-08-12 06:17:17 +0000[diff] [blame]4989<div>
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]4990
4991<h5>Syntax:</h5>
4992<pre>
Eli Friedman02e737b2011-08-12 22:50:01 +0000[diff] [blame]4993 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 Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]4994</pre>
4995
4996<h5>Overview:</h5>
4997<p>The '<tt>atomicrmw</tt>' instruction is used to atomically modify memory.</p>
4998
4999<h5>Arguments:</h5>
5000<p>There are three arguments to the '<code>atomicrmw</code>' instruction: an
5001operation to apply, an address whose value to modify, an argument to the
5002operation. The operation must be one of the following keywords:</p>
5003<ul>
5004 <li>xchg</li>
5005 <li>add</li>
5006 <li>sub</li>
5007 <li>and</li>
5008 <li>nand</li>
5009 <li>or</li>
5010 <li>xor</li>
5011 <li>max</li>
5012 <li>min</li>
5013 <li>umax</li>
5014 <li>umin</li>
5015</ul>
5016
5017<p>The type of '<var>&lt;value&gt;</var>' must be an integer type whose
5018bit width is a power of two greater than or equal to eight and less than
5019or equal to a target-specific size limit. The type of the
5020'<code>&lt;pointer&gt;</code>' operand must be a pointer to that type.
5021If the <code>atomicrmw</code> is marked as <code>volatile</code>, then the
5022optimizer is not allowed to modify the number or order of execution of this
5023<code>atomicrmw</code> with other <a href="#volatile">volatile
5024 operations</a>.</p>
5025
5026<!-- FIXME: Extend allowed types. -->
5027
5028<h5>Semantics:</h5>
5029<p>The contents of memory at the location specified by the
5030'<tt>&lt;pointer&gt;</tt>' operand are atomically read, modified, and written
5031back. The original value at the location is returned. The modification is
5032specified by the <var>operation</var> argument:</p>
5033
5034<ul>
5035 <li>xchg: <code>*ptr = val</code></li>
5036 <li>add: <code>*ptr = *ptr + val</code></li>
5037 <li>sub: <code>*ptr = *ptr - val</code></li>
5038 <li>and: <code>*ptr = *ptr &amp; val</code></li>
5039 <li>nand: <code>*ptr = ~(*ptr &amp; val)</code></li>
5040 <li>or: <code>*ptr = *ptr | val</code></li>
5041 <li>xor: <code>*ptr = *ptr ^ val</code></li>
5042 <li>max: <code>*ptr = *ptr &gt; val ? *ptr : val</code> (using a signed comparison)</li>
5043 <li>min: <code>*ptr = *ptr &lt; val ? *ptr : val</code> (using a signed comparison)</li>
5044 <li>umax: <code>*ptr = *ptr &gt; val ? *ptr : val</code> (using an unsigned comparison)</li>
5045 <li>umin: <code>*ptr = *ptr &lt; val ? *ptr : val</code> (using an unsigned comparison)</li>
5046</ul>
5047
5048<h5>Example:</h5>
5049<pre>
5050 %old = atomicrmw add i32* %ptr, i32 1 acquire <i>; yields {i32}</i>
5051</pre>
5052
5053</div>
5054
5055<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5056<h4>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]5057 <a name="i_getelementptr">'<tt>getelementptr</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5058</h4>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]5059
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5060<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5061
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]5062<h5>Syntax:</h5>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]5063<pre>
Matthijs Kooijman0e268272008-10-13 13:44:15 +0000[diff] [blame]5064 &lt;result&gt; = getelementptr &lt;pty&gt;* &lt;ptrval&gt;{, &lt;ty&gt; &lt;idx&gt;}*
Dan Gohman1639c392009-07-27 21:53:46 +0000[diff] [blame]5065 &lt;result&gt; = getelementptr inbounds &lt;pty&gt;* &lt;ptrval&gt;{, &lt;ty&gt; &lt;idx&gt;}*
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]5066</pre>
5067
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]5068<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5069<p>The '<tt>getelementptr</tt>' instruction is used to get the address of a
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]5070 subelement of an <a href="#t_aggregate">aggregate</a> data structure.
5071 It performs address calculation only and does not access memory.</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]5072
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]5073<h5>Arguments:</h5>
Matthijs Kooijman0e268272008-10-13 13:44:15 +0000[diff] [blame]5074<p>The first argument is always a pointer, and forms the basis of the
Chris Lattnera40b9122009-07-29 06:44:13 +0000[diff] [blame]5075 calculation. The remaining arguments are indices that indicate which of the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5076 elements of the aggregate object are indexed. The interpretation of each
5077 index is dependent on the type being indexed into. The first index always
5078 indexes the pointer value given as the first argument, the second index
5079 indexes a value of the type pointed to (not necessarily the value directly
5080 pointed to, since the first index can be non-zero), etc. The first type
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]5081 indexed into must be a pointer value, subsequent types can be arrays,
Chris Lattner13ee7952010-08-28 04:09:24 +0000[diff] [blame]5082 vectors, and structs. Note that subsequent types being indexed into
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]5083 can never be pointers, since that would require loading the pointer before
5084 continuing calculation.</p>
Matthijs Kooijman0e268272008-10-13 13:44:15 +0000[diff] [blame]5085
5086<p>The type of each index argument depends on the type it is indexing into.
Chris Lattner13ee7952010-08-28 04:09:24 +0000[diff] [blame]5087 When indexing into a (optionally packed) structure, only <tt>i32</tt>
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]5088 integer <b>constants</b> are allowed. When indexing into an array, pointer
5089 or vector, integers of any width are allowed, and they are not required to be
Eli Friedmand8874dc2011-08-12 23:37:55 +0000[diff] [blame]5090 constant. These integers are treated as signed values where relevant.</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]5091
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5092<p>For example, let's consider a C code fragment and how it gets compiled to
5093 LLVM:</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]5094
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]5095<pre class="doc_code">
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]5096struct RT {
5097 char A;
Chris Lattnera446f1b2007-05-29 15:43:56 +0000[diff] [blame]5098 int B[10][20];
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]5099 char C;
5100};
5101struct ST {
Chris Lattnera446f1b2007-05-29 15:43:56 +0000[diff] [blame]5102 int X;
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]5103 double Y;
5104 struct RT Z;
5105};
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]5106
Chris Lattnera446f1b2007-05-29 15:43:56 +0000[diff] [blame]5107int *foo(struct ST *s) {
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]5108 return &amp;s[1].Z.B[5][13];
5109}
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]5110</pre>
5111
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5112<p>The LLVM code generated by the GCC frontend is:</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]5113
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]5114<pre class="doc_code">
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]5115%RT = <a href="#namedtypes">type</a> { i8 , [10 x [20 x i32]], i8 }
5116%ST = <a href="#namedtypes">type</a> { i32, double, %RT }
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]5117
Dan Gohman6b867702009-07-25 02:23:48 +0000[diff] [blame]5118define i32* @foo(%ST* %s) {
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]5119entry:
5120 %reg = getelementptr %ST* %s, i32 1, i32 2, i32 1, i32 5, i32 13
5121 ret i32* %reg
5122}
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]5123</pre>
5124
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]5125<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5126<p>In the example above, the first index is indexing into the '<tt>%ST*</tt>'
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5127 type, which is a pointer, yielding a '<tt>%ST</tt>' = '<tt>{ i32, double, %RT
5128 }</tt>' type, a structure. The second index indexes into the third element
5129 of the structure, yielding a '<tt>%RT</tt>' = '<tt>{ i8 , [10 x [20 x i32]],
5130 i8 }</tt>' type, another structure. The third index indexes into the second
5131 element of the structure, yielding a '<tt>[10 x [20 x i32]]</tt>' type, an
5132 array. The two dimensions of the array are subscripted into, yielding an
5133 '<tt>i32</tt>' type. The '<tt>getelementptr</tt>' instruction returns a
5134 pointer to this element, thus computing a value of '<tt>i32*</tt>' type.</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]5135
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5136<p>Note that it is perfectly legal to index partially through a structure,
5137 returning a pointer to an inner element. Because of this, the LLVM code for
5138 the given testcase is equivalent to:</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]5139
5140<pre>
Dan Gohman6b867702009-07-25 02:23:48 +0000[diff] [blame]5141 define i32* @foo(%ST* %s) {
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]5142 %t1 = getelementptr %ST* %s, i32 1 <i>; yields %ST*:%t1</i>
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]5143 %t2 = getelementptr %ST* %t1, i32 0, i32 2 <i>; yields %RT*:%t2</i>
5144 %t3 = getelementptr %RT* %t2, i32 0, i32 1 <i>; yields [10 x [20 x i32]]*:%t3</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]5145 %t4 = getelementptr [10 x [20 x i32]]* %t3, i32 0, i32 5 <i>; yields [20 x i32]*:%t4</i>
5146 %t5 = getelementptr [20 x i32]* %t4, i32 0, i32 13 <i>; yields i32*:%t5</i>
5147 ret i32* %t5
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]5148 }
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]5149</pre>
Chris Lattnerc0ad71e2005-06-24 17:22:57 +0000[diff] [blame]5150
Dan Gohman1639c392009-07-27 21:53:46 +0000[diff] [blame]5151<p>If the <tt>inbounds</tt> keyword is present, the result value of the
Dan Gohman57255802010-04-23 15:23:32 +0000[diff] [blame]5152 <tt>getelementptr</tt> is a <a href="#trapvalues">trap value</a> if the
5153 base pointer is not an <i>in bounds</i> address of an allocated object,
5154 or if any of the addresses that would be formed by successive addition of
5155 the offsets implied by the indices to the base address with infinitely
Eli Friedmand8874dc2011-08-12 23:37:55 +0000[diff] [blame]5156 precise signed arithmetic are not an <i>in bounds</i> address of that
5157 allocated object. The <i>in bounds</i> addresses for an allocated object
5158 are all the addresses that point into the object, plus the address one
5159 byte past the end.</p>
Dan Gohman1639c392009-07-27 21:53:46 +0000[diff] [blame]5160
5161<p>If the <tt>inbounds</tt> keyword is not present, the offsets are added to
Eli Friedmand8874dc2011-08-12 23:37:55 +0000[diff] [blame]5162 the base address with silently-wrapping two's complement arithmetic. If the
5163 offsets have a different width from the pointer, they are sign-extended or
5164 truncated to the width of the pointer. The result value of the
5165 <tt>getelementptr</tt> may be outside the object pointed to by the base
5166 pointer. The result value may not necessarily be used to access memory
5167 though, even if it happens to point into allocated storage. See the
5168 <a href="#pointeraliasing">Pointer Aliasing Rules</a> section for more
5169 information.</p>
Dan Gohman1639c392009-07-27 21:53:46 +0000[diff] [blame]5170
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5171<p>The getelementptr instruction is often confusing. For some more insight into
5172 how it works, see <a href="GetElementPtr.html">the getelementptr FAQ</a>.</p>
Chris Lattner6ab66722006-08-15 00:45:58 +0000[diff] [blame]5173
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]5174<h5>Example:</h5>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]5175<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]5176 <i>; yields [12 x i8]*:aptr</i>
Matthijs Kooijman0e268272008-10-13 13:44:15 +0000[diff] [blame]5177 %aptr = getelementptr {i32, [12 x i8]}* %saptr, i64 0, i32 1
5178 <i>; yields i8*:vptr</i>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]5179 %vptr = getelementptr {i32, &lt;2 x i8&gt;}* %svptr, i64 0, i32 1, i32 1
Matthijs Kooijman0e268272008-10-13 13:44:15 +0000[diff] [blame]5180 <i>; yields i8*:eptr</i>
5181 %eptr = getelementptr [12 x i8]* %aptr, i64 0, i32 1
Sanjiv Gupta0c155e62009-04-25 07:27:44 +0000[diff] [blame]5182 <i>; yields i32*:iptr</i>
Sanjiv Gupta77abea02009-04-24 16:38:13 +0000[diff] [blame]5183 %iptr = getelementptr [10 x i32]* @arr, i16 0, i16 0
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]5184</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5185
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]5186</div>
Reid Spencer443460a2006-11-09 21:15:49 +0000[diff] [blame]5187
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5188</div>
5189
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]5190<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5191<h3>
5192 <a name="convertops">Conversion Operations</a>
5193</h3>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5194
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5195<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5196
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5197<p>The instructions in this category are the conversion instructions (casting)
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5198 which all take a single operand and a type. They perform various bit
5199 conversions on the operand.</p>
5200
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]5201<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5202<h4>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5203 <a name="i_trunc">'<tt>trunc .. to</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5204</h4>
5205
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5206<div>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5207
5208<h5>Syntax:</h5>
5209<pre>
5210 &lt;result&gt; = trunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
5211</pre>
5212
5213<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5214<p>The '<tt>trunc</tt>' instruction truncates its operand to the
5215 type <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5216
5217<h5>Arguments:</h5>
Nadav Rotem502f1b92011-02-24 21:01:34 +0000[diff] [blame]5218<p>The '<tt>trunc</tt>' instruction takes a value to trunc, and a type to trunc it to.
5219 Both types must be of <a href="#t_integer">integer</a> types, or vectors
5220 of the same number of integers.
5221 The bit size of the <tt>value</tt> must be larger than
5222 the bit size of the destination type, <tt>ty2</tt>.
5223 Equal sized types are not allowed.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5224
5225<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5226<p>The '<tt>trunc</tt>' instruction truncates the high order bits
5227 in <tt>value</tt> and converts the remaining bits to <tt>ty2</tt>. Since the
5228 source size must be larger than the destination size, <tt>trunc</tt> cannot
5229 be a <i>no-op cast</i>. It will always truncate bits.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5230
5231<h5>Example:</h5>
5232<pre>
Nadav Rotem502f1b92011-02-24 21:01:34 +0000[diff] [blame]5233 %X = trunc i32 257 to i8 <i>; yields i8:1</i>
5234 %Y = trunc i32 123 to i1 <i>; yields i1:true</i>
5235 %Z = trunc i32 122 to i1 <i>; yields i1:false</i>
5236 %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 Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5237</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5238
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5239</div>
5240
5241<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5242<h4>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5243 <a name="i_zext">'<tt>zext .. to</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5244</h4>
5245
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5246<div>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5247
5248<h5>Syntax:</h5>
5249<pre>
5250 &lt;result&gt; = zext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
5251</pre>
5252
5253<h5>Overview:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5254<p>The '<tt>zext</tt>' instruction zero extends its operand to type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5255 <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5256
5257
5258<h5>Arguments:</h5>
Nadav Rotem25f2ac92011-02-20 12:37:50 +0000[diff] [blame]5259<p>The '<tt>zext</tt>' instruction takes a value to cast, and a type to cast it to.
5260 Both types must be of <a href="#t_integer">integer</a> types, or vectors
5261 of the same number of integers.
5262 The bit size of the <tt>value</tt> must be smaller than
5263 the bit size of the destination type,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5264 <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5265
5266<h5>Semantics:</h5>
5267<p>The <tt>zext</tt> fills the high order bits of the <tt>value</tt> with zero
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5268 bits until it reaches the size of the destination type, <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5269
Reid Spencer07c9c682007-01-12 15:46:11 +0000[diff] [blame]5270<p>When zero extending from i1, the result will always be either 0 or 1.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5271
5272<h5>Example:</h5>
5273<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]5274 %X = zext i32 257 to i64 <i>; yields i64:257</i>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]5275 %Y = zext i1 true to i32 <i>; yields i32:1</i>
Nadav Rotem25f2ac92011-02-20 12:37:50 +0000[diff] [blame]5276 %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 Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5277</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5278
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5279</div>
5280
5281<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5282<h4>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5283 <a name="i_sext">'<tt>sext .. to</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5284</h4>
5285
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5286<div>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5287
5288<h5>Syntax:</h5>
5289<pre>
5290 &lt;result&gt; = sext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
5291</pre>
5292
5293<h5>Overview:</h5>
5294<p>The '<tt>sext</tt>' sign extends <tt>value</tt> to the type <tt>ty2</tt>.</p>
5295
5296<h5>Arguments:</h5>
Nadav Rotem502f1b92011-02-24 21:01:34 +0000[diff] [blame]5297<p>The '<tt>sext</tt>' instruction takes a value to cast, and a type to cast it to.
5298 Both types must be of <a href="#t_integer">integer</a> types, or vectors
5299 of the same number of integers.
5300 The bit size of the <tt>value</tt> must be smaller than
5301 the bit size of the destination type,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5302 <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5303
5304<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5305<p>The '<tt>sext</tt>' instruction performs a sign extension by copying the sign
5306 bit (highest order bit) of the <tt>value</tt> until it reaches the bit size
5307 of the type <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5308
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]5309<p>When sign extending from i1, the extension always results in -1 or 0.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5310
5311<h5>Example:</h5>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5312<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]5313 %X = sext i8 -1 to i16 <i>; yields i16 :65535</i>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]5314 %Y = sext i1 true to i32 <i>; yields i32:-1</i>
Nadav Rotem502f1b92011-02-24 21:01:34 +0000[diff] [blame]5315 %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 Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5316</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5317
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5318</div>
5319
5320<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5321<h4>
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]5322 <a name="i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5323</h4>
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]5324
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5325<div>
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]5326
5327<h5>Syntax:</h5>
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]5328<pre>
5329 &lt;result&gt; = fptrunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
5330</pre>
5331
5332<h5>Overview:</h5>
5333<p>The '<tt>fptrunc</tt>' instruction truncates <tt>value</tt> to type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5334 <tt>ty2</tt>.</p>
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]5335
5336<h5>Arguments:</h5>
5337<p>The '<tt>fptrunc</tt>' instruction takes a <a href="#t_floating">floating
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5338 point</a> value to cast and a <a href="#t_floating">floating point</a> type
5339 to cast it to. The size of <tt>value</tt> must be larger than the size of
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5340 <tt>ty2</tt>. This implies that <tt>fptrunc</tt> cannot be used to make a
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5341 <i>no-op cast</i>.</p>
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]5342
5343<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5344<p>The '<tt>fptrunc</tt>' instruction truncates a <tt>value</tt> from a larger
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5345 <a href="#t_floating">floating point</a> type to a smaller
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5346 <a href="#t_floating">floating point</a> type. If the value cannot fit
5347 within the destination type, <tt>ty2</tt>, then the results are
5348 undefined.</p>
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]5349
5350<h5>Example:</h5>
5351<pre>
5352 %X = fptrunc double 123.0 to float <i>; yields float:123.0</i>
5353 %Y = fptrunc double 1.0E+300 to float <i>; yields undefined</i>
5354</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5355
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]5356</div>
5357
5358<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5359<h4>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5360 <a name="i_fpext">'<tt>fpext .. to</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5361</h4>
5362
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5363<div>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5364
5365<h5>Syntax:</h5>
5366<pre>
5367 &lt;result&gt; = fpext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
5368</pre>
5369
5370<h5>Overview:</h5>
5371<p>The '<tt>fpext</tt>' extends a floating point <tt>value</tt> to a larger
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5372 floating point value.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5373
5374<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5375<p>The '<tt>fpext</tt>' instruction takes a
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5376 <a href="#t_floating">floating point</a> <tt>value</tt> to cast, and
5377 a <a href="#t_floating">floating point</a> type to cast it to. The source
5378 type must be smaller than the destination type.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5379
5380<h5>Semantics:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]5381<p>The '<tt>fpext</tt>' instruction extends the <tt>value</tt> from a smaller
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5382 <a href="#t_floating">floating point</a> type to a larger
5383 <a href="#t_floating">floating point</a> type. The <tt>fpext</tt> cannot be
5384 used to make a <i>no-op cast</i> because it always changes bits. Use
5385 <tt>bitcast</tt> to make a <i>no-op cast</i> for a floating point cast.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5386
5387<h5>Example:</h5>
5388<pre>
Nick Lewycky9feca672011-03-31 18:20:19 +0000[diff] [blame]5389 %X = fpext float 3.125 to double <i>; yields double:3.125000e+00</i>
5390 %Y = fpext double %X to fp128 <i>; yields fp128:0xL00000000000000004000900000000000</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5391</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5392
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5393</div>
5394
5395<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5396<h4>
Reid Spencer2eadb532007-01-21 00:29:26 +0000[diff] [blame]5397 <a name="i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5398</h4>
5399
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5400<div>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5401
5402<h5>Syntax:</h5>
5403<pre>
Reid Spencer753163d2007-07-31 14:40:14 +0000[diff] [blame]5404 &lt;result&gt; = fptoui &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5405</pre>
5406
5407<h5>Overview:</h5>
Reid Spencer753163d2007-07-31 14:40:14 +0000[diff] [blame]5408<p>The '<tt>fptoui</tt>' converts a floating point <tt>value</tt> to its
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5409 unsigned integer equivalent of type <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5410
5411<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5412<p>The '<tt>fptoui</tt>' instruction takes a value to cast, which must be a
5413 scalar or vector <a href="#t_floating">floating point</a> value, and a type
5414 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
5415 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
5416 vector integer type with the same number of elements as <tt>ty</tt></p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5417
5418<h5>Semantics:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5419<p>The '<tt>fptoui</tt>' instruction converts its
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5420 <a href="#t_floating">floating point</a> operand into the nearest (rounding
5421 towards zero) unsigned integer value. If the value cannot fit
5422 in <tt>ty2</tt>, the results are undefined.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5423
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5424<h5>Example:</h5>
5425<pre>
Reid Spencer753163d2007-07-31 14:40:14 +0000[diff] [blame]5426 %X = fptoui double 123.0 to i32 <i>; yields i32:123</i>
Chris Lattner5b95a172007-09-22 03:17:52 +0000[diff] [blame]5427 %Y = fptoui float 1.0E+300 to i1 <i>; yields undefined:1</i>
Gabor Greiff50fd572009-10-28 09:21:30 +0000[diff] [blame]5428 %Z = fptoui float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5429</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5430
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5431</div>
5432
5433<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5434<h4>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]5435 <a name="i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5436</h4>
5437
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5438<div>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5439
5440<h5>Syntax:</h5>
5441<pre>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]5442 &lt;result&gt; = fptosi &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5443</pre>
5444
5445<h5>Overview:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5446<p>The '<tt>fptosi</tt>' instruction converts
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5447 <a href="#t_floating">floating point</a> <tt>value</tt> to
5448 type <tt>ty2</tt>.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5449
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]5450<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5451<p>The '<tt>fptosi</tt>' instruction takes a value to cast, which must be a
5452 scalar or vector <a href="#t_floating">floating point</a> value, and a type
5453 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
5454 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
5455 vector integer type with the same number of elements as <tt>ty</tt></p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5456
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]5457<h5>Semantics:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5458<p>The '<tt>fptosi</tt>' instruction converts its
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5459 <a href="#t_floating">floating point</a> operand into the nearest (rounding
5460 towards zero) signed integer value. If the value cannot fit in <tt>ty2</tt>,
5461 the results are undefined.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5462
Chris Lattner70de6632001-07-09 00:26:23 +0000[diff] [blame]5463<h5>Example:</h5>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5464<pre>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]5465 %X = fptosi double -123.0 to i32 <i>; yields i32:-123</i>
Chris Lattner5b95a172007-09-22 03:17:52 +0000[diff] [blame]5466 %Y = fptosi float 1.0E-247 to i1 <i>; yields undefined:1</i>
Gabor Greiff50fd572009-10-28 09:21:30 +0000[diff] [blame]5467 %Z = fptosi float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5468</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5469
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5470</div>
5471
5472<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5473<h4>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]5474 <a name="i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5475</h4>
5476
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5477<div>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5478
5479<h5>Syntax:</h5>
5480<pre>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]5481 &lt;result&gt; = uitofp &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5482</pre>
5483
5484<h5>Overview:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]5485<p>The '<tt>uitofp</tt>' instruction regards <tt>value</tt> as an unsigned
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5486 integer and converts that value to the <tt>ty2</tt> type.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5487
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5488<h5>Arguments:</h5>
Nate Begemand4d45c22007-11-17 03:58:34 +0000[diff] [blame]5489<p>The '<tt>uitofp</tt>' instruction takes a value to cast, which must be a
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5490 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
5491 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
5492 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
5493 floating point type with the same number of elements as <tt>ty</tt></p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5494
5495<h5>Semantics:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]5496<p>The '<tt>uitofp</tt>' instruction interprets its operand as an unsigned
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5497 integer quantity and converts it to the corresponding floating point
5498 value. If the value cannot fit in the floating point value, the results are
5499 undefined.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5500
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5501<h5>Example:</h5>
5502<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]5503 %X = uitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]5504 %Y = uitofp i8 -1 to double <i>; yields double:255.0</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5505</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5506
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5507</div>
5508
5509<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5510<h4>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]5511 <a name="i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5512</h4>
5513
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5514<div>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5515
5516<h5>Syntax:</h5>
5517<pre>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]5518 &lt;result&gt; = sitofp &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5519</pre>
5520
5521<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5522<p>The '<tt>sitofp</tt>' instruction regards <tt>value</tt> as a signed integer
5523 and converts that value to the <tt>ty2</tt> type.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5524
5525<h5>Arguments:</h5>
Nate Begemand4d45c22007-11-17 03:58:34 +0000[diff] [blame]5526<p>The '<tt>sitofp</tt>' instruction takes a value to cast, which must be a
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5527 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
5528 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
5529 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
5530 floating point type with the same number of elements as <tt>ty</tt></p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5531
5532<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5533<p>The '<tt>sitofp</tt>' instruction interprets its operand as a signed integer
5534 quantity and converts it to the corresponding floating point value. If the
5535 value cannot fit in the floating point value, the results are undefined.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5536
5537<h5>Example:</h5>
5538<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]5539 %X = sitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]5540 %Y = sitofp i8 -1 to double <i>; yields double:-1.0</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5541</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5542
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5543</div>
5544
5545<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5546<h4>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]5547 <a name="i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5548</h4>
5549
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5550<div>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]5551
5552<h5>Syntax:</h5>
5553<pre>
5554 &lt;result&gt; = ptrtoint &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
5555</pre>
5556
5557<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5558<p>The '<tt>ptrtoint</tt>' instruction converts the pointer <tt>value</tt> to
5559 the integer type <tt>ty2</tt>.</p>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]5560
5561<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5562<p>The '<tt>ptrtoint</tt>' instruction takes a <tt>value</tt> to cast, which
5563 must be a <a href="#t_pointer">pointer</a> value, and a type to cast it to
5564 <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a> type.</p>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]5565
5566<h5>Semantics:</h5>
5567<p>The '<tt>ptrtoint</tt>' instruction converts <tt>value</tt> to integer type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5568 <tt>ty2</tt> by interpreting the pointer value as an integer and either
5569 truncating or zero extending that value to the size of the integer type. If
5570 <tt>value</tt> is smaller than <tt>ty2</tt> then a zero extension is done. If
5571 <tt>value</tt> is larger than <tt>ty2</tt> then a truncation is done. If they
5572 are the same size, then nothing is done (<i>no-op cast</i>) other than a type
5573 change.</p>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]5574
5575<h5>Example:</h5>
5576<pre>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5577 %X = ptrtoint i32* %X to i8 <i>; yields truncation on 32-bit architecture</i>
5578 %Y = ptrtoint i32* %x to i64 <i>; yields zero extension on 32-bit architecture</i>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]5579</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5580
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]5581</div>
5582
5583<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5584<h4>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]5585 <a name="i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5586</h4>
5587
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5588<div>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]5589
5590<h5>Syntax:</h5>
5591<pre>
5592 &lt;result&gt; = inttoptr &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
5593</pre>
5594
5595<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5596<p>The '<tt>inttoptr</tt>' instruction converts an integer <tt>value</tt> to a
5597 pointer type, <tt>ty2</tt>.</p>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]5598
5599<h5>Arguments:</h5>
Duncan Sands16f122e2007-03-30 12:22:09 +0000[diff] [blame]5600<p>The '<tt>inttoptr</tt>' instruction takes an <a href="#t_integer">integer</a>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5601 value to cast, and a type to cast it to, which must be a
5602 <a href="#t_pointer">pointer</a> type.</p>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]5603
5604<h5>Semantics:</h5>
5605<p>The '<tt>inttoptr</tt>' instruction converts <tt>value</tt> to type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5606 <tt>ty2</tt> by applying either a zero extension or a truncation depending on
5607 the size of the integer <tt>value</tt>. If <tt>value</tt> is larger than the
5608 size of a pointer then a truncation is done. If <tt>value</tt> is smaller
5609 than the size of a pointer then a zero extension is done. If they are the
5610 same size, nothing is done (<i>no-op cast</i>).</p>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]5611
5612<h5>Example:</h5>
5613<pre>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5614 %X = inttoptr i32 255 to i32* <i>; yields zero extension on 64-bit architecture</i>
Gabor Greiff50fd572009-10-28 09:21:30 +0000[diff] [blame]5615 %Y = inttoptr i32 255 to i32* <i>; yields no-op on 32-bit architecture</i>
5616 %Z = inttoptr i64 0 to i32* <i>; yields truncation on 32-bit architecture</i>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]5617</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5618
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]5619</div>
5620
5621<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5622<h4>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]5623 <a name="i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5624</h4>
5625
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5626<div>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5627
5628<h5>Syntax:</h5>
5629<pre>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]5630 &lt;result&gt; = bitcast &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5631</pre>
5632
5633<h5>Overview:</h5>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]5634<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5635 <tt>ty2</tt> without changing any bits.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5636
5637<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5638<p>The '<tt>bitcast</tt>' instruction takes a value to cast, which must be a
5639 non-aggregate first class value, and a type to cast it to, which must also be
5640 a non-aggregate <a href="#t_firstclass">first class</a> type. The bit sizes
5641 of <tt>value</tt> and the destination type, <tt>ty2</tt>, must be
5642 identical. If the source type is a pointer, the destination type must also be
5643 a pointer. This instruction supports bitwise conversion of vectors to
5644 integers and to vectors of other types (as long as they have the same
5645 size).</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5646
5647<h5>Semantics:</h5>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]5648<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5649 <tt>ty2</tt>. It is always a <i>no-op cast</i> because no bits change with
5650 this conversion. The conversion is done as if the <tt>value</tt> had been
5651 stored to memory and read back as type <tt>ty2</tt>. Pointer types may only
5652 be converted to other pointer types with this instruction. To convert
5653 pointers to other types, use the <a href="#i_inttoptr">inttoptr</a> or
5654 <a href="#i_ptrtoint">ptrtoint</a> instructions first.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5655
5656<h5>Example:</h5>
5657<pre>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5658 %X = bitcast i8 255 to i8 <i>; yields i8 :-1</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]5659 %Y = bitcast i32* %x to sint* <i>; yields sint*:%x</i>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5660 %Z = bitcast &lt;2 x int&gt; %V to i64; <i>; yields i64: %V</i>
Chris Lattner70de6632001-07-09 00:26:23 +0000[diff] [blame]5661</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5662
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5663</div>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5664
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5665</div>
5666
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5667<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5668<h3>
5669 <a name="otherops">Other Operations</a>
5670</h3>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5671
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5672<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5673
5674<p>The instructions in this category are the "miscellaneous" instructions, which
5675 defy better classification.</p>
5676
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5677<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5678<h4>
5679 <a name="i_icmp">'<tt>icmp</tt>' Instruction</a>
5680</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5681
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5682<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5683
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5684<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5685<pre>
5686 &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 Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5687</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5688
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5689<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5690<p>The '<tt>icmp</tt>' instruction returns a boolean value or a vector of
5691 boolean values based on comparison of its two integer, integer vector, or
5692 pointer operands.</p>
5693
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5694<h5>Arguments:</h5>
5695<p>The '<tt>icmp</tt>' instruction takes three operands. The first operand is
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5696 the condition code indicating the kind of comparison to perform. It is not a
5697 value, just a keyword. The possible condition code are:</p>
5698
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5699<ol>
5700 <li><tt>eq</tt>: equal</li>
5701 <li><tt>ne</tt>: not equal </li>
5702 <li><tt>ugt</tt>: unsigned greater than</li>
5703 <li><tt>uge</tt>: unsigned greater or equal</li>
5704 <li><tt>ult</tt>: unsigned less than</li>
5705 <li><tt>ule</tt>: unsigned less or equal</li>
5706 <li><tt>sgt</tt>: signed greater than</li>
5707 <li><tt>sge</tt>: signed greater or equal</li>
5708 <li><tt>slt</tt>: signed less than</li>
5709 <li><tt>sle</tt>: signed less or equal</li>
5710</ol>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5711
Chris Lattnerc0f423a2007-01-15 01:54:13 +0000[diff] [blame]5712<p>The remaining two arguments must be <a href="#t_integer">integer</a> or
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5713 <a href="#t_pointer">pointer</a> or integer <a href="#t_vector">vector</a>
5714 typed. They must also be identical types.</p>
5715
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5716<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5717<p>The '<tt>icmp</tt>' compares <tt>op1</tt> and <tt>op2</tt> according to the
5718 condition code given as <tt>cond</tt>. The comparison performed always yields
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]5719 either an <a href="#t_integer"><tt>i1</tt></a> or vector of <tt>i1</tt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5720 result, as follows:</p>
5721
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5722<ol>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5723 <li><tt>eq</tt>: yields <tt>true</tt> if the operands are equal,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5724 <tt>false</tt> otherwise. No sign interpretation is necessary or
5725 performed.</li>
5726
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5727 <li><tt>ne</tt>: yields <tt>true</tt> if the operands are unequal,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5728 <tt>false</tt> otherwise. No sign interpretation is necessary or
5729 performed.</li>
5730
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5731 <li><tt>ugt</tt>: interprets the operands as unsigned values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5732 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
5733
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5734 <li><tt>uge</tt>: interprets the operands as unsigned values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5735 <tt>true</tt> if <tt>op1</tt> is greater than or equal
5736 to <tt>op2</tt>.</li>
5737
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5738 <li><tt>ult</tt>: interprets the operands as unsigned values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5739 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
5740
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5741 <li><tt>ule</tt>: interprets the operands as unsigned values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5742 <tt>true</tt> if <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
5743
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5744 <li><tt>sgt</tt>: interprets the operands as signed values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5745 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
5746
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5747 <li><tt>sge</tt>: interprets the operands as signed values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5748 <tt>true</tt> if <tt>op1</tt> is greater than or equal
5749 to <tt>op2</tt>.</li>
5750
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5751 <li><tt>slt</tt>: interprets the operands as signed values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5752 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
5753
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5754 <li><tt>sle</tt>: interprets the operands as signed values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5755 <tt>true</tt> if <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5756</ol>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5757
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5758<p>If the operands are <a href="#t_pointer">pointer</a> typed, the pointer
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5759 values are compared as if they were integers.</p>
5760
5761<p>If the operands are integer vectors, then they are compared element by
5762 element. The result is an <tt>i1</tt> vector with the same number of elements
5763 as the values being compared. Otherwise, the result is an <tt>i1</tt>.</p>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5764
5765<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5766<pre>
5767 &lt;result&gt; = icmp eq i32 4, 5 <i>; yields: result=false</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]5768 &lt;result&gt; = icmp ne float* %X, %X <i>; yields: result=false</i>
5769 &lt;result&gt; = icmp ult i16 4, 5 <i>; yields: result=true</i>
5770 &lt;result&gt; = icmp sgt i16 4, 5 <i>; yields: result=false</i>
5771 &lt;result&gt; = icmp ule i16 -4, 5 <i>; yields: result=false</i>
5772 &lt;result&gt; = icmp sge i16 4, 5 <i>; yields: result=false</i>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5773</pre>
Dan Gohmana5127ab2009-01-22 01:39:38 +0000[diff] [blame]5774
5775<p>Note that the code generator does not yet support vector types with
5776 the <tt>icmp</tt> instruction.</p>
5777
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5778</div>
5779
5780<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5781<h4>
5782 <a name="i_fcmp">'<tt>fcmp</tt>' Instruction</a>
5783</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5784
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5785<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5786
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5787<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5788<pre>
5789 &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 Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5790</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5791
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5792<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5793<p>The '<tt>fcmp</tt>' instruction returns a boolean value or vector of boolean
5794 values based on comparison of its operands.</p>
5795
5796<p>If the operands are floating point scalars, then the result type is a boolean
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]5797(<a href="#t_integer"><tt>i1</tt></a>).</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5798
5799<p>If the operands are floating point vectors, then the result type is a vector
5800 of boolean with the same number of elements as the operands being
5801 compared.</p>
5802
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5803<h5>Arguments:</h5>
5804<p>The '<tt>fcmp</tt>' instruction takes three operands. The first operand is
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5805 the condition code indicating the kind of comparison to perform. It is not a
5806 value, just a keyword. The possible condition code are:</p>
5807
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5808<ol>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]5809 <li><tt>false</tt>: no comparison, always returns false</li>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5810 <li><tt>oeq</tt>: ordered and equal</li>
5811 <li><tt>ogt</tt>: ordered and greater than </li>
5812 <li><tt>oge</tt>: ordered and greater than or equal</li>
5813 <li><tt>olt</tt>: ordered and less than </li>
5814 <li><tt>ole</tt>: ordered and less than or equal</li>
5815 <li><tt>one</tt>: ordered and not equal</li>
5816 <li><tt>ord</tt>: ordered (no nans)</li>
5817 <li><tt>ueq</tt>: unordered or equal</li>
5818 <li><tt>ugt</tt>: unordered or greater than </li>
5819 <li><tt>uge</tt>: unordered or greater than or equal</li>
5820 <li><tt>ult</tt>: unordered or less than </li>
5821 <li><tt>ule</tt>: unordered or less than or equal</li>
5822 <li><tt>une</tt>: unordered or not equal</li>
5823 <li><tt>uno</tt>: unordered (either nans)</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]5824 <li><tt>true</tt>: no comparison, always returns true</li>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5825</ol>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5826
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5827<p><i>Ordered</i> means that neither operand is a QNAN while
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5828 <i>unordered</i> means that either operand may be a QNAN.</p>
5829
5830<p>Each of <tt>val1</tt> and <tt>val2</tt> arguments must be either
5831 a <a href="#t_floating">floating point</a> type or
5832 a <a href="#t_vector">vector</a> of floating point type. They must have
5833 identical types.</p>
5834
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5835<h5>Semantics:</h5>
Gabor Greif0f75ad02008-08-07 21:46:00 +0000[diff] [blame]5836<p>The '<tt>fcmp</tt>' instruction compares <tt>op1</tt> and <tt>op2</tt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5837 according to the condition code given as <tt>cond</tt>. If the operands are
5838 vectors, then the vectors are compared element by element. Each comparison
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]5839 performed always yields an <a href="#t_integer">i1</a> result, as
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5840 follows:</p>
5841
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5842<ol>
5843 <li><tt>false</tt>: always yields <tt>false</tt>, regardless of operands.</li>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5844
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5845 <li><tt>oeq</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5846 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
5847
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]5848 <li><tt>ogt</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]5849 <tt>op1</tt> is greater than <tt>op2</tt>.</li>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5850
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5851 <li><tt>oge</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5852 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
5853
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5854 <li><tt>olt</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5855 <tt>op1</tt> is less than <tt>op2</tt>.</li>
5856
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5857 <li><tt>ole</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5858 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
5859
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5860 <li><tt>one</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5861 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
5862
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]5863 <li><tt>ord</tt>: yields <tt>true</tt> if both operands are not a QNAN.</li>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5864
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5865 <li><tt>ueq</tt>: yields <tt>true</tt> if either operand is a QNAN or
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5866 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
5867
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5868 <li><tt>ugt</tt>: yields <tt>true</tt> if either operand is a QNAN or
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5869 <tt>op1</tt> is greater than <tt>op2</tt>.</li>
5870
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5871 <li><tt>uge</tt>: yields <tt>true</tt> if either operand is a QNAN or
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5872 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
5873
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5874 <li><tt>ult</tt>: yields <tt>true</tt> if either operand is a QNAN or
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5875 <tt>op1</tt> is less than <tt>op2</tt>.</li>
5876
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5877 <li><tt>ule</tt>: yields <tt>true</tt> if either operand is a QNAN or
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5878 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
5879
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5880 <li><tt>une</tt>: yields <tt>true</tt> if either operand is a QNAN or
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5881 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
5882
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]5883 <li><tt>uno</tt>: yields <tt>true</tt> if either operand is a QNAN.</li>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5884
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5885 <li><tt>true</tt>: always yields <tt>true</tt>, regardless of operands.</li>
5886</ol>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5887
5888<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5889<pre>
5890 &lt;result&gt; = fcmp oeq float 4.0, 5.0 <i>; yields: result=false</i>
Dan Gohmanc579d972008-09-09 01:02:47 +0000[diff] [blame]5891 &lt;result&gt; = fcmp one float 4.0, 5.0 <i>; yields: result=true</i>
5892 &lt;result&gt; = fcmp olt float 4.0, 5.0 <i>; yields: result=true</i>
5893 &lt;result&gt; = fcmp ueq double 1.0, 2.0 <i>; yields: result=false</i>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5894</pre>
Dan Gohmana5127ab2009-01-22 01:39:38 +0000[diff] [blame]5895
5896<p>Note that the code generator does not yet support vector types with
5897 the <tt>fcmp</tt> instruction.</p>
5898
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5899</div>
5900
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5901<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5902<h4>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]5903 <a name="i_phi">'<tt>phi</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5904</h4>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]5905
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5906<div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]5907
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5908<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5909<pre>
5910 &lt;result&gt; = phi &lt;ty&gt; [ &lt;val0&gt;, &lt;label0&gt;], ...
5911</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]5912
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5913<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5914<p>The '<tt>phi</tt>' instruction is used to implement the &#966; node in the
5915 SSA graph representing the function.</p>
5916
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5917<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5918<p>The type of the incoming values is specified with the first type field. After
5919 this, the '<tt>phi</tt>' instruction takes a list of pairs as arguments, with
5920 one pair for each predecessor basic block of the current block. Only values
5921 of <a href="#t_firstclass">first class</a> type may be used as the value
5922 arguments to the PHI node. Only labels may be used as the label
5923 arguments.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]5924
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5925<p>There must be no non-phi instructions between the start of a basic block and
5926 the PHI instructions: i.e. PHI instructions must be first in a basic
5927 block.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]5928
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5929<p>For the purposes of the SSA form, the use of each incoming value is deemed to
5930 occur on the edge from the corresponding predecessor block to the current
5931 block (but after any definition of an '<tt>invoke</tt>' instruction's return
5932 value on the same edge).</p>
Jay Foad1a4eea52009-06-03 10:20:10 +0000[diff] [blame]5933
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5934<h5>Semantics:</h5>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5935<p>At runtime, the '<tt>phi</tt>' instruction logically takes on the value
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5936 specified by the pair corresponding to the predecessor basic block that
5937 executed just prior to the current block.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]5938
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5939<h5>Example:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]5940<pre>
5941Loop: ; Infinite loop that counts from 0 on up...
5942 %indvar = phi i32 [ 0, %LoopHeader ], [ %nextindvar, %Loop ]
5943 %nextindvar = add i32 %indvar, 1
5944 br label %Loop
5945</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5946
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5947</div>
5948
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5949<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5950<h4>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5951 <a name="i_select">'<tt>select</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5952</h4>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5953
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5954<div>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5955
5956<h5>Syntax:</h5>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5957<pre>
Dan Gohmanc579d972008-09-09 01:02:47 +0000[diff] [blame]5958 &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>
5959
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]5960 <i>selty</i> is either i1 or {&lt;N x i1&gt;}
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5961</pre>
5962
5963<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5964<p>The '<tt>select</tt>' instruction is used to choose one value based on a
5965 condition, without branching.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5966
5967
5968<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5969<p>The '<tt>select</tt>' instruction requires an 'i1' value or a vector of 'i1'
5970 values indicating the condition, and two values of the
5971 same <a href="#t_firstclass">first class</a> type. If the val1/val2 are
5972 vectors and the condition is a scalar, then entire vectors are selected, not
5973 individual elements.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5974
5975<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5976<p>If the condition is an i1 and it evaluates to 1, the instruction returns the
5977 first value argument; otherwise, it returns the second value argument.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5978
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5979<p>If the condition is a vector of i1, then the value arguments must be vectors
5980 of the same size, and the selection is done element by element.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5981
5982<h5>Example:</h5>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5983<pre>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]5984 %X = select i1 true, i8 17, i8 42 <i>; yields i8:17</i>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5985</pre>
Dan Gohmana5127ab2009-01-22 01:39:38 +0000[diff] [blame]5986
5987<p>Note that the code generator does not yet support conditions
5988 with vector type.</p>
5989
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5990</div>
5991
Robert Bocchinof72fdfe2006-01-15 20:48:27 +0000[diff] [blame]5992<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5993<h4>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5994 <a name="i_call">'<tt>call</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5995</h4>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5996
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5997<div>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5998
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]5999<h5>Syntax:</h5>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]6000<pre>
Devang Patel02256232008-10-07 17:48:33 +0000[diff] [blame]6001 &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 Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]6002</pre>
6003
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]6004<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]6005<p>The '<tt>call</tt>' instruction represents a simple function call.</p>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]6006
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]6007<h5>Arguments:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]6008<p>This instruction requires several arguments:</p>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]6009
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]6010<ol>
Jeffrey Yasskinb8677462010-01-09 19:44:16 +0000[diff] [blame]6011 <li>The optional "tail" marker indicates that the callee function does not
6012 access any allocas or varargs in the caller. Note that calls may be
6013 marked "tail" even if they do not occur before
6014 a <a href="#i_ret"><tt>ret</tt></a> instruction. If the "tail" marker is
6015 present, the function call is eligible for tail call optimization,
6016 but <a href="CodeGenerator.html#tailcallopt">might not in fact be
Evan Cheng59676492010-03-08 21:05:02 +0000[diff] [blame]6017 optimized into a jump</a>. The code generator may optimize calls marked
6018 "tail" with either 1) automatic <a href="CodeGenerator.html#sibcallopt">
6019 sibling call optimization</a> when the caller and callee have
6020 matching signatures, or 2) forced tail call optimization when the
6021 following extra requirements are met:
Jeffrey Yasskinb8677462010-01-09 19:44:16 +0000[diff] [blame]6022 <ul>
6023 <li>Caller and callee both have the calling
6024 convention <tt>fastcc</tt>.</li>
6025 <li>The call is in tail position (ret immediately follows call and ret
6026 uses value of call or is void).</li>
6027 <li>Option <tt>-tailcallopt</tt> is enabled,
Dan Gohman6232f732010-03-02 01:08:11 +0000[diff] [blame]6028 or <code>llvm::GuaranteedTailCallOpt</code> is <code>true</code>.</li>
Jeffrey Yasskinb8677462010-01-09 19:44:16 +0000[diff] [blame]6029 <li><a href="CodeGenerator.html#tailcallopt">Platform specific
6030 constraints are met.</a></li>
6031 </ul>
6032 </li>
Devang Patel7e9b05e2008-10-06 18:50:38 +0000[diff] [blame]6033
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6034 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
6035 convention</a> the call should use. If none is specified, the call
Jeffrey Yasskinb8677462010-01-09 19:44:16 +0000[diff] [blame]6036 defaults to using C calling conventions. The calling convention of the
6037 call must match the calling convention of the target function, or else the
6038 behavior is undefined.</li>
Devang Patel7e9b05e2008-10-06 18:50:38 +0000[diff] [blame]6039
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6040 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
6041 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
6042 '<tt>inreg</tt>' attributes are valid here.</li>
6043
6044 <li>'<tt>ty</tt>': the type of the call instruction itself which is also the
6045 type of the return value. Functions that return no value are marked
6046 <tt><a href="#t_void">void</a></tt>.</li>
6047
6048 <li>'<tt>fnty</tt>': shall be the signature of the pointer to function value
6049 being invoked. The argument types must match the types implied by this
6050 signature. This type can be omitted if the function is not varargs and if
6051 the function type does not return a pointer to a function.</li>
6052
6053 <li>'<tt>fnptrval</tt>': An LLVM value containing a pointer to a function to
6054 be invoked. In most cases, this is a direct function invocation, but
6055 indirect <tt>call</tt>s are just as possible, calling an arbitrary pointer
6056 to function value.</li>
6057
6058 <li>'<tt>function args</tt>': argument list whose types match the function
Chris Lattner47f2a832010-03-02 06:36:51 +0000[diff] [blame]6059 signature argument types and parameter attributes. All arguments must be
6060 of <a href="#t_firstclass">first class</a> type. If the function
6061 signature indicates the function accepts a variable number of arguments,
6062 the extra arguments can be specified.</li>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6063
6064 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
6065 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
6066 '<tt>readnone</tt>' attributes are valid here.</li>
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]6067</ol>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]6068
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]6069<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6070<p>The '<tt>call</tt>' instruction is used to cause control flow to transfer to
6071 a specified function, with its incoming arguments bound to the specified
6072 values. Upon a '<tt><a href="#i_ret">ret</a></tt>' instruction in the called
6073 function, control flow continues with the instruction after the function
6074 call, and the return value of the function is bound to the result
6075 argument.</p>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]6076
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]6077<h5>Example:</h5>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]6078<pre>
Nick Lewyckya9b13d52007-09-08 13:57:50 +0000[diff] [blame]6079 %retval = call i32 @test(i32 %argc)
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]6080 call i32 (i8*, ...)* @printf(i8* %msg, i32 12, i8 42) <i>; yields i32</i>
Chris Lattnerfb7c88d2008-03-21 17:24:17 +0000[diff] [blame]6081 %X = tail call i32 @foo() <i>; yields i32</i>
6082 %Y = tail call <a href="#callingconv">fastcc</a> i32 @foo() <i>; yields i32</i>
6083 call void %foo(i8 97 signext)
Devang Pateld6cff512008-03-10 20:49:15 +0000[diff] [blame]6084
6085 %struct.A = type { i32, i8 }
Devang Patel7e9b05e2008-10-06 18:50:38 +0000[diff] [blame]6086 %r = call %struct.A @foo() <i>; yields { 32, i8 }</i>
Dan Gohmancc3132e2008-10-04 19:00:07 +0000[diff] [blame]6087 %gr = extractvalue %struct.A %r, 0 <i>; yields i32</i>
6088 %gr1 = extractvalue %struct.A %r, 1 <i>; yields i8</i>
Chris Lattner6cbe8e92008-10-08 06:26:11 +0000[diff] [blame]6089 %Z = call void @foo() noreturn <i>; indicates that %foo never returns normally</i>
Matthijs Kooijmaneefa7df2008-10-07 10:03:45 +0000[diff] [blame]6090 %ZZ = call zeroext i32 @bar() <i>; Return value is %zero extended</i>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]6091</pre>
6092
Dale Johannesen68f971b2009-09-24 18:38:21 +0000[diff] [blame]6093<p>llvm treats calls to some functions with names and arguments that match the
Dale Johannesen722212d2009-09-25 17:04:42 +0000[diff] [blame]6094standard C99 library as being the C99 library functions, and may perform
6095optimizations or generate code for them under that assumption. This is
6096something we'd like to change in the future to provide better support for
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]6097freestanding environments and non-C-based languages.</p>
Dale Johannesen68f971b2009-09-24 18:38:21 +0000[diff] [blame]6098
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]6099</div>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]6100
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]6101<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6102<h4>
Chris Lattner33337472006-01-13 23:26:01 +0000[diff] [blame]6103 <a name="i_va_arg">'<tt>va_arg</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6104</h4>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]6105
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6106<div>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]6107
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]6108<h5>Syntax:</h5>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]6109<pre>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]6110 &lt;resultval&gt; = va_arg &lt;va_list*&gt; &lt;arglist&gt;, &lt;argty&gt;
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]6111</pre>
6112
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]6113<h5>Overview:</h5>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]6114<p>The '<tt>va_arg</tt>' instruction is used to access arguments passed through
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6115 the "variable argument" area of a function call. It is used to implement the
6116 <tt>va_arg</tt> macro in C.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]6117
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]6118<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6119<p>This instruction takes a <tt>va_list*</tt> value and the type of the
6120 argument. It returns a value of the specified argument type and increments
6121 the <tt>va_list</tt> to point to the next argument. The actual type
6122 of <tt>va_list</tt> is target specific.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]6123
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]6124<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6125<p>The '<tt>va_arg</tt>' instruction loads an argument of the specified type
6126 from the specified <tt>va_list</tt> and causes the <tt>va_list</tt> to point
6127 to the next argument. For more information, see the variable argument
6128 handling <a href="#int_varargs">Intrinsic Functions</a>.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]6129
6130<p>It is legal for this instruction to be called in a function which does not
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6131 take a variable number of arguments, for example, the <tt>vfprintf</tt>
6132 function.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]6133
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6134<p><tt>va_arg</tt> is an LLVM instruction instead of
6135 an <a href="#intrinsics">intrinsic function</a> because it takes a type as an
6136 argument.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]6137
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]6138<h5>Example:</h5>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]6139<p>See the <a href="#int_varargs">variable argument processing</a> section.</p>
6140
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6141<p>Note that the code generator does not yet fully support va_arg on many
6142 targets. Also, it does not currently support va_arg with aggregate types on
6143 any target.</p>
Dan Gohman3065b612009-01-12 23:12:39 +0000[diff] [blame]6144
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]6145</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]6146
Bill Wendlingbbcb7cd2011-08-02 21:52:38 +0000[diff] [blame]6147<!-- _______________________________________________________________________ -->
6148<h4>
6149 <a name="i_landingpad">'<tt>landingpad</tt>' Instruction</a>
6150</h4>
6151
6152<div>
6153
6154<h5>Syntax:</h5>
6155<pre>
Bill Wendling49bfb122011-08-08 08:06:05 +0000[diff] [blame]6156 &lt;resultval&gt; = landingpad &lt;somety&gt; personality &lt;type&gt; &lt;pers_fn&gt; &lt;clause&gt;+
6157 &lt;resultval&gt; = landingpad &lt;somety&gt; personality &lt;type&gt; &lt;pers_fn&gt; cleanup &lt;clause&gt;*
6158
Bill Wendlingbbcb7cd2011-08-02 21:52:38 +0000[diff] [blame]6159 &lt;clause&gt; := catch &lt;type&gt; &lt;value&gt;
Bill Wendlingfae14752011-08-12 20:24:12 +0000[diff] [blame]6160 &lt;clause&gt; := filter &lt;array constant type&gt; &lt;array constant&gt;
Bill Wendlingbbcb7cd2011-08-02 21:52:38 +0000[diff] [blame]6161</pre>
6162
6163<h5>Overview:</h5>
6164<p>The '<tt>landingpad</tt>' instruction is used by
6165 <a href="ExceptionHandling.html#overview">LLVM's exception handling
6166 system</a> to specify that a basic block is a landing pad &mdash; one where
6167 the exception lands, and corresponds to the code found in the
6168 <i><tt>catch</tt></i> portion of a <i><tt>try/catch</tt></i> sequence. It
6169 defines values supplied by the personality function (<tt>pers_fn</tt>) upon
6170 re-entry to the function. The <tt>resultval</tt> has the
6171 type <tt>somety</tt>.</p>
6172
6173<h5>Arguments:</h5>
6174<p>This instruction takes a <tt>pers_fn</tt> value. This is the personality
6175 function associated with the unwinding mechanism. The optional
6176 <tt>cleanup</tt> flag indicates that the landing pad block is a cleanup.</p>
6177
6178<p>A <tt>clause</tt> begins with the clause type &mdash; <tt>catch</tt>
Bill Wendlingfae14752011-08-12 20:24:12 +0000[diff] [blame]6179 or <tt>filter</tt> &mdash; and contains the global variable representing the
6180 "type" that may be caught or filtered respectively. Unlike the
6181 <tt>catch</tt> clause, the <tt>filter</tt> clause takes an array constant as
6182 its argument. Use "<tt>[0 x i8**] undef</tt>" for a filter which cannot
6183 throw. The '<tt>landingpad</tt>' instruction must contain <em>at least</em>
Bill Wendlingbbcb7cd2011-08-02 21:52:38 +0000[diff] [blame]6184 one <tt>clause</tt> or the <tt>cleanup</tt> flag.</p>
6185
6186<h5>Semantics:</h5>
6187<p>The '<tt>landingpad</tt>' instruction defines the values which are set by the
6188 personality function (<tt>pers_fn</tt>) upon re-entry to the function, and
6189 therefore the "result type" of the <tt>landingpad</tt> instruction. As with
6190 calling conventions, how the personality function results are represented in
6191 LLVM IR is target specific.</p>
6192
Bill Wendling0524b8d2011-08-03 17:17:06 +0000[diff] [blame]6193<p>The clauses are applied in order from top to bottom. If two
6194 <tt>landingpad</tt> instructions are merged together through inlining, the
Bill Wendlinga503fc02011-08-08 07:58:58 +0000[diff] [blame]6195 clauses from the calling function are appended to the list of clauses.</p>
Bill Wendling0524b8d2011-08-03 17:17:06 +0000[diff] [blame]6196
Bill Wendlingbbcb7cd2011-08-02 21:52:38 +0000[diff] [blame]6197<p>The <tt>landingpad</tt> instruction has several restrictions:</p>
6198
6199<ul>
6200 <li>A landing pad block is a basic block which is the unwind destination of an
6201 '<tt>invoke</tt>' instruction.</li>
6202 <li>A landing pad block must have a '<tt>landingpad</tt>' instruction as its
6203 first non-PHI instruction.</li>
6204 <li>There can be only one '<tt>landingpad</tt>' instruction within the landing
6205 pad block.</li>
6206 <li>A basic block that is not a landing pad block may not include a
6207 '<tt>landingpad</tt>' instruction.</li>
6208 <li>All '<tt>landingpad</tt>' instructions in a function must have the same
6209 personality function.</li>
6210</ul>
6211
6212<h5>Example:</h5>
6213<pre>
6214 ;; A landing pad which can catch an integer.
6215 %res = landingpad { i8*, i32 } personality i32 (...)* @__gxx_personality_v0
6216 catch i8** @_ZTIi
6217 ;; A landing pad that is a cleanup.
6218 %res = landingpad { i8*, i32 } personality i32 (...)* @__gxx_personality_v0
Bill Wendlingfae14752011-08-12 20:24:12 +0000[diff] [blame]6219 cleanup
Bill Wendlingbbcb7cd2011-08-02 21:52:38 +0000[diff] [blame]6220 ;; A landing pad which can catch an integer and can only throw a double.
6221 %res = landingpad { i8*, i32 } personality i32 (...)* @__gxx_personality_v0
6222 catch i8** @_ZTIi
Bill Wendlingfae14752011-08-12 20:24:12 +0000[diff] [blame]6223 filter [1 x i8**] [@_ZTId]
Bill Wendlingbbcb7cd2011-08-02 21:52:38 +0000[diff] [blame]6224</pre>
6225
6226</div>
6227
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6228</div>
6229
6230</div>
6231
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]6232<!-- *********************************************************************** -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6233<h2><a name="intrinsics">Intrinsic Functions</a></h2>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]6234<!-- *********************************************************************** -->
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]6235
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6236<div>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6237
6238<p>LLVM supports the notion of an "intrinsic function". These functions have
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6239 well known names and semantics and are required to follow certain
6240 restrictions. Overall, these intrinsics represent an extension mechanism for
6241 the LLVM language that does not require changing all of the transformations
6242 in LLVM when adding to the language (or the bitcode reader/writer, the
6243 parser, etc...).</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6244
John Criswell88190562005-05-16 16:17:45 +0000[diff] [blame]6245<p>Intrinsic function names must all start with an "<tt>llvm.</tt>" prefix. This
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6246 prefix is reserved in LLVM for intrinsic names; thus, function names may not
6247 begin with this prefix. Intrinsic functions must always be external
6248 functions: you cannot define the body of intrinsic functions. Intrinsic
6249 functions may only be used in call or invoke instructions: it is illegal to
6250 take the address of an intrinsic function. Additionally, because intrinsic
6251 functions are part of the LLVM language, it is required if any are added that
6252 they be documented here.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6253
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6254<p>Some intrinsic functions can be overloaded, i.e., the intrinsic represents a
6255 family of functions that perform the same operation but on different data
6256 types. Because LLVM can represent over 8 million different integer types,
6257 overloading is used commonly to allow an intrinsic function to operate on any
6258 integer type. One or more of the argument types or the result type can be
6259 overloaded to accept any integer type. Argument types may also be defined as
6260 exactly matching a previous argument's type or the result type. This allows
6261 an intrinsic function which accepts multiple arguments, but needs all of them
6262 to be of the same type, to only be overloaded with respect to a single
6263 argument or the result.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6264
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6265<p>Overloaded intrinsics will have the names of its overloaded argument types
6266 encoded into its function name, each preceded by a period. Only those types
6267 which are overloaded result in a name suffix. Arguments whose type is matched
6268 against another type do not. For example, the <tt>llvm.ctpop</tt> function
6269 can take an integer of any width and returns an integer of exactly the same
6270 integer width. This leads to a family of functions such as
6271 <tt>i8 @llvm.ctpop.i8(i8 %val)</tt> and <tt>i29 @llvm.ctpop.i29(i29
6272 %val)</tt>. Only one type, the return type, is overloaded, and only one type
6273 suffix is required. Because the argument's type is matched against the return
6274 type, it does not require its own name suffix.</p>
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]6275
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]6276<p>To learn how to add an intrinsic function, please see the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6277 <a href="ExtendingLLVM.html">Extending LLVM Guide</a>.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6278
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]6279<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6280<h3>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]6281 <a name="int_varargs">Variable Argument Handling Intrinsics</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6282</h3>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]6283
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6284<div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6285
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6286<p>Variable argument support is defined in LLVM with
6287 the <a href="#i_va_arg"><tt>va_arg</tt></a> instruction and these three
6288 intrinsic functions. These functions are related to the similarly named
6289 macros defined in the <tt>&lt;stdarg.h&gt;</tt> header file.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6290
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6291<p>All of these functions operate on arguments that use a target-specific value
6292 type "<tt>va_list</tt>". The LLVM assembly language reference manual does
6293 not define what this type is, so all transformations should be prepared to
6294 handle these functions regardless of the type used.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6295
Chris Lattner30b868d2006-05-15 17:26:46 +0000[diff] [blame]6296<p>This example shows how the <a href="#i_va_arg"><tt>va_arg</tt></a>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6297 instruction and the variable argument handling intrinsic functions are
6298 used.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6299
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]6300<pre class="doc_code">
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]6301define i32 @test(i32 %X, ...) {
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6302 ; Initialize variable argument processing
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]6303 %ap = alloca i8*
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]6304 %ap2 = bitcast i8** %ap to i8*
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]6305 call void @llvm.va_start(i8* %ap2)
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6306
6307 ; Read a single integer argument
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]6308 %tmp = va_arg i8** %ap, i32
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6309
6310 ; Demonstrate usage of llvm.va_copy and llvm.va_end
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]6311 %aq = alloca i8*
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]6312 %aq2 = bitcast i8** %aq to i8*
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]6313 call void @llvm.va_copy(i8* %aq2, i8* %ap2)
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]6314 call void @llvm.va_end(i8* %aq2)
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6315
6316 ; Stop processing of arguments.
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]6317 call void @llvm.va_end(i8* %ap2)
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]6318 ret i32 %tmp
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6319}
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]6320
6321declare void @llvm.va_start(i8*)
6322declare void @llvm.va_copy(i8*, i8*)
6323declare void @llvm.va_end(i8*)
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6324</pre>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]6325
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]6326<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6327<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6328 <a name="int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6329</h4>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]6330
6331
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6332<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6333
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]6334<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6335<pre>
6336 declare void %llvm.va_start(i8* &lt;arglist&gt;)
6337</pre>
6338
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]6339<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6340<p>The '<tt>llvm.va_start</tt>' intrinsic initializes <tt>*&lt;arglist&gt;</tt>
6341 for subsequent use by <tt><a href="#i_va_arg">va_arg</a></tt>.</p>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]6342
6343<h5>Arguments:</h5>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]6344<p>The argument is a pointer to a <tt>va_list</tt> element to initialize.</p>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]6345
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]6346<h5>Semantics:</h5>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]6347<p>The '<tt>llvm.va_start</tt>' intrinsic works just like the <tt>va_start</tt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6348 macro available in C. In a target-dependent way, it initializes
6349 the <tt>va_list</tt> element to which the argument points, so that the next
6350 call to <tt>va_arg</tt> will produce the first variable argument passed to
6351 the function. Unlike the C <tt>va_start</tt> macro, this intrinsic does not
6352 need to know the last argument of the function as the compiler can figure
6353 that out.</p>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]6354
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]6355</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]6356
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]6357<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6358<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6359 <a name="int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6360</h4>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]6361
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6362<div>
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]6363
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6364<h5>Syntax:</h5>
6365<pre>
6366 declare void @llvm.va_end(i8* &lt;arglist&gt;)
6367</pre>
6368
6369<h5>Overview:</h5>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]6370<p>The '<tt>llvm.va_end</tt>' intrinsic destroys <tt>*&lt;arglist&gt;</tt>,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6371 which has been initialized previously
6372 with <tt><a href="#int_va_start">llvm.va_start</a></tt>
6373 or <tt><a href="#i_va_copy">llvm.va_copy</a></tt>.</p>
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]6374
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]6375<h5>Arguments:</h5>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]6376<p>The argument is a pointer to a <tt>va_list</tt> to destroy.</p>
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]6377
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]6378<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]6379<p>The '<tt>llvm.va_end</tt>' intrinsic works just like the <tt>va_end</tt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6380 macro available in C. In a target-dependent way, it destroys
6381 the <tt>va_list</tt> element to which the argument points. Calls
6382 to <a href="#int_va_start"><tt>llvm.va_start</tt></a>
6383 and <a href="#int_va_copy"> <tt>llvm.va_copy</tt></a> must be matched exactly
6384 with calls to <tt>llvm.va_end</tt>.</p>
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]6385
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]6386</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]6387
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]6388<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6389<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6390 <a name="int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6391</h4>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]6392
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6393<div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6394
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]6395<h5>Syntax:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6396<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]6397 declare void @llvm.va_copy(i8* &lt;destarglist&gt;, i8* &lt;srcarglist&gt;)
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6398</pre>
6399
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]6400<h5>Overview:</h5>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]6401<p>The '<tt>llvm.va_copy</tt>' intrinsic copies the current argument position
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6402 from the source argument list to the destination argument list.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6403
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]6404<h5>Arguments:</h5>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]6405<p>The first argument is a pointer to a <tt>va_list</tt> element to initialize.
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6406 The second argument is a pointer to a <tt>va_list</tt> element to copy
6407 from.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6408
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]6409<h5>Semantics:</h5>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]6410<p>The '<tt>llvm.va_copy</tt>' intrinsic works just like the <tt>va_copy</tt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6411 macro available in C. In a target-dependent way, it copies the
6412 source <tt>va_list</tt> element into the destination <tt>va_list</tt>
6413 element. This intrinsic is necessary because
6414 the <tt><a href="#int_va_start"> llvm.va_start</a></tt> intrinsic may be
6415 arbitrarily complex and require, for example, memory allocation.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6416
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]6417</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]6418
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6419</div>
6420
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6421<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6422<h3>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6423 <a name="int_gc">Accurate Garbage Collection Intrinsics</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6424</h3>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6425
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6426<div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6427
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6428<p>LLVM support for <a href="GarbageCollection.html">Accurate Garbage
Chris Lattner67c37d12008-08-05 18:29:16 +0000[diff] [blame]6429Collection</a> (GC) requires the implementation and generation of these
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6430intrinsics. These intrinsics allow identification of <a href="#int_gcroot">GC
6431roots on the stack</a>, as well as garbage collector implementations that
6432require <a href="#int_gcread">read</a> and <a href="#int_gcwrite">write</a>
6433barriers. Front-ends for type-safe garbage collected languages should generate
6434these intrinsics to make use of the LLVM garbage collectors. For more details,
6435see <a href="GarbageCollection.html">Accurate Garbage Collection with
6436LLVM</a>.</p>
Christopher Lamb55c6d4f2007-12-17 01:00:21 +0000[diff] [blame]6437
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6438<p>The garbage collection intrinsics only operate on objects in the generic
6439 address space (address space zero).</p>
Christopher Lamb55c6d4f2007-12-17 01:00:21 +0000[diff] [blame]6440
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6441<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6442<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6443 <a name="int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6444</h4>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6445
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6446<div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6447
6448<h5>Syntax:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6449<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]6450 declare void @llvm.gcroot(i8** %ptrloc, i8* %metadata)
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6451</pre>
6452
6453<h5>Overview:</h5>
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]6454<p>The '<tt>llvm.gcroot</tt>' intrinsic declares the existence of a GC root to
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6455 the code generator, and allows some metadata to be associated with it.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6456
6457<h5>Arguments:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6458<p>The first argument specifies the address of a stack object that contains the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6459 root pointer. The second pointer (which must be either a constant or a
6460 global value address) contains the meta-data to be associated with the
6461 root.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6462
6463<h5>Semantics:</h5>
Chris Lattner851b7712008-04-24 05:59:56 +0000[diff] [blame]6464<p>At runtime, a call to this intrinsic stores a null pointer into the "ptrloc"
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6465 location. At compile-time, the code generator generates information to allow
6466 the runtime to find the pointer at GC safe points. The '<tt>llvm.gcroot</tt>'
6467 intrinsic may only be used in a function which <a href="#gc">specifies a GC
6468 algorithm</a>.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6469
6470</div>
6471
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6472<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6473<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6474 <a name="int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6475</h4>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6476
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6477<div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6478
6479<h5>Syntax:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6480<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]6481 declare i8* @llvm.gcread(i8* %ObjPtr, i8** %Ptr)
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6482</pre>
6483
6484<h5>Overview:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6485<p>The '<tt>llvm.gcread</tt>' intrinsic identifies reads of references from heap
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6486 locations, allowing garbage collector implementations that require read
6487 barriers.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6488
6489<h5>Arguments:</h5>
Chris Lattnerf9228072006-03-14 20:02:51 +0000[diff] [blame]6490<p>The second argument is the address to read from, which should be an address
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6491 allocated from the garbage collector. The first object is a pointer to the
6492 start of the referenced object, if needed by the language runtime (otherwise
6493 null).</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6494
6495<h5>Semantics:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6496<p>The '<tt>llvm.gcread</tt>' intrinsic has the same semantics as a load
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6497 instruction, but may be replaced with substantially more complex code by the
6498 garbage collector runtime, as needed. The '<tt>llvm.gcread</tt>' intrinsic
6499 may only be used in a function which <a href="#gc">specifies a GC
6500 algorithm</a>.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6501
6502</div>
6503
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6504<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6505<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6506 <a name="int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6507</h4>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6508
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6509<div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6510
6511<h5>Syntax:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6512<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]6513 declare void @llvm.gcwrite(i8* %P1, i8* %Obj, i8** %P2)
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6514</pre>
6515
6516<h5>Overview:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6517<p>The '<tt>llvm.gcwrite</tt>' intrinsic identifies writes of references to heap
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6518 locations, allowing garbage collector implementations that require write
6519 barriers (such as generational or reference counting collectors).</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6520
6521<h5>Arguments:</h5>
Chris Lattnerf9228072006-03-14 20:02:51 +0000[diff] [blame]6522<p>The first argument is the reference to store, the second is the start of the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6523 object to store it to, and the third is the address of the field of Obj to
6524 store to. If the runtime does not require a pointer to the object, Obj may
6525 be null.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6526
6527<h5>Semantics:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6528<p>The '<tt>llvm.gcwrite</tt>' intrinsic has the same semantics as a store
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6529 instruction, but may be replaced with substantially more complex code by the
6530 garbage collector runtime, as needed. The '<tt>llvm.gcwrite</tt>' intrinsic
6531 may only be used in a function which <a href="#gc">specifies a GC
6532 algorithm</a>.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6533
6534</div>
6535
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6536</div>
6537
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6538<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6539<h3>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6540 <a name="int_codegen">Code Generator Intrinsics</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6541</h3>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6542
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6543<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6544
6545<p>These intrinsics are provided by LLVM to expose special features that may
6546 only be implemented with code generator support.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6547
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6548<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6549<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6550 <a name="int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6551</h4>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6552
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6553<div>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6554
6555<h5>Syntax:</h5>
6556<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]6557 declare i8 *@llvm.returnaddress(i32 &lt;level&gt;)
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6558</pre>
6559
6560<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6561<p>The '<tt>llvm.returnaddress</tt>' intrinsic attempts to compute a
6562 target-specific value indicating the return address of the current function
6563 or one of its callers.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6564
6565<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6566<p>The argument to this intrinsic indicates which function to return the address
6567 for. Zero indicates the calling function, one indicates its caller, etc.
6568 The argument is <b>required</b> to be a constant integer value.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6569
6570<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6571<p>The '<tt>llvm.returnaddress</tt>' intrinsic either returns a pointer
6572 indicating the return address of the specified call frame, or zero if it
6573 cannot be identified. The value returned by this intrinsic is likely to be
6574 incorrect or 0 for arguments other than zero, so it should only be used for
6575 debugging purposes.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6576
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6577<p>Note that calling this intrinsic does not prevent function inlining or other
6578 aggressive transformations, so the value returned may not be that of the
6579 obvious source-language caller.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6580
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6581</div>
6582
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6583<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6584<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6585 <a name="int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6586</h4>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6587
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6588<div>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6589
6590<h5>Syntax:</h5>
6591<pre>
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]6592 declare i8* @llvm.frameaddress(i32 &lt;level&gt;)
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6593</pre>
6594
6595<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6596<p>The '<tt>llvm.frameaddress</tt>' intrinsic attempts to return the
6597 target-specific frame pointer value for the specified stack frame.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6598
6599<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6600<p>The argument to this intrinsic indicates which function to return the frame
6601 pointer for. Zero indicates the calling function, one indicates its caller,
6602 etc. The argument is <b>required</b> to be a constant integer value.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6603
6604<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6605<p>The '<tt>llvm.frameaddress</tt>' intrinsic either returns a pointer
6606 indicating the frame address of the specified call frame, or zero if it
6607 cannot be identified. The value returned by this intrinsic is likely to be
6608 incorrect or 0 for arguments other than zero, so it should only be used for
6609 debugging purposes.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6610
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6611<p>Note that calling this intrinsic does not prevent function inlining or other
6612 aggressive transformations, so the value returned may not be that of the
6613 obvious source-language caller.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6614
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6615</div>
6616
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]6617<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6618<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6619 <a name="int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6620</h4>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]6621
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6622<div>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]6623
6624<h5>Syntax:</h5>
6625<pre>
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]6626 declare i8* @llvm.stacksave()
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]6627</pre>
6628
6629<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6630<p>The '<tt>llvm.stacksave</tt>' intrinsic is used to remember the current state
6631 of the function stack, for use
6632 with <a href="#int_stackrestore"> <tt>llvm.stackrestore</tt></a>. This is
6633 useful for implementing language features like scoped automatic variable
6634 sized arrays in C99.</p>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]6635
6636<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6637<p>This intrinsic returns a opaque pointer value that can be passed
6638 to <a href="#int_stackrestore"><tt>llvm.stackrestore</tt></a>. When
6639 an <tt>llvm.stackrestore</tt> intrinsic is executed with a value saved
6640 from <tt>llvm.stacksave</tt>, it effectively restores the state of the stack
6641 to the state it was in when the <tt>llvm.stacksave</tt> intrinsic executed.
6642 In practice, this pops any <a href="#i_alloca">alloca</a> blocks from the
6643 stack that were allocated after the <tt>llvm.stacksave</tt> was executed.</p>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]6644
6645</div>
6646
6647<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6648<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6649 <a name="int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6650</h4>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]6651
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6652<div>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]6653
6654<h5>Syntax:</h5>
6655<pre>
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]6656 declare void @llvm.stackrestore(i8* %ptr)
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]6657</pre>
6658
6659<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6660<p>The '<tt>llvm.stackrestore</tt>' intrinsic is used to restore the state of
6661 the function stack to the state it was in when the
6662 corresponding <a href="#int_stacksave"><tt>llvm.stacksave</tt></a> intrinsic
6663 executed. This is useful for implementing language features like scoped
6664 automatic variable sized arrays in C99.</p>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]6665
6666<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6667<p>See the description
6668 for <a href="#int_stacksave"><tt>llvm.stacksave</tt></a>.</p>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]6669
6670</div>
6671
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]6672<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6673<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6674 <a name="int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6675</h4>
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]6676
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6677<div>
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]6678
6679<h5>Syntax:</h5>
6680<pre>
Bruno Cardoso Lopesdc9ff3a2011-06-14 04:58:37 +0000[diff] [blame]6681 declare void @llvm.prefetch(i8* &lt;address&gt;, i32 &lt;rw&gt;, i32 &lt;locality&gt;, i32 &lt;cache type&gt;)
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]6682</pre>
6683
6684<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6685<p>The '<tt>llvm.prefetch</tt>' intrinsic is a hint to the code generator to
6686 insert a prefetch instruction if supported; otherwise, it is a noop.
6687 Prefetches have no effect on the behavior of the program but can change its
6688 performance characteristics.</p>
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]6689
6690<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6691<p><tt>address</tt> is the address to be prefetched, <tt>rw</tt> is the
6692 specifier determining if the fetch should be for a read (0) or write (1),
6693 and <tt>locality</tt> is a temporal locality specifier ranging from (0) - no
Bruno Cardoso Lopesdc9ff3a2011-06-14 04:58:37 +0000[diff] [blame]6694 locality, to (3) - extremely local keep in cache. The <tt>cache type</tt>
6695 specifies whether the prefetch is performed on the data (1) or instruction (0)
6696 cache. The <tt>rw</tt>, <tt>locality</tt> and <tt>cache type</tt> arguments
6697 must be constant integers.</p>
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]6698
6699<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6700<p>This intrinsic does not modify the behavior of the program. In particular,
6701 prefetches cannot trap and do not produce a value. On targets that support
6702 this intrinsic, the prefetch can provide hints to the processor cache for
6703 better performance.</p>
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]6704
6705</div>
6706
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]6707<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6708<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6709 <a name="int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6710</h4>
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]6711
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6712<div>
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]6713
6714<h5>Syntax:</h5>
6715<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]6716 declare void @llvm.pcmarker(i32 &lt;id&gt;)
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]6717</pre>
6718
6719<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6720<p>The '<tt>llvm.pcmarker</tt>' intrinsic is a method to export a Program
6721 Counter (PC) in a region of code to simulators and other tools. The method
6722 is target specific, but it is expected that the marker will use exported
6723 symbols to transmit the PC of the marker. The marker makes no guarantees
6724 that it will remain with any specific instruction after optimizations. It is
6725 possible that the presence of a marker will inhibit optimizations. The
6726 intended use is to be inserted after optimizations to allow correlations of
6727 simulation runs.</p>
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]6728
6729<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6730<p><tt>id</tt> is a numerical id identifying the marker.</p>
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]6731
6732<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6733<p>This intrinsic does not modify the behavior of the program. Backends that do
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]6734 not support this intrinsic may ignore it.</p>
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]6735
6736</div>
6737
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]6738<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6739<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6740 <a name="int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6741</h4>
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]6742
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6743<div>
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]6744
6745<h5>Syntax:</h5>
6746<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]6747 declare i64 @llvm.readcyclecounter()
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]6748</pre>
6749
6750<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6751<p>The '<tt>llvm.readcyclecounter</tt>' intrinsic provides access to the cycle
6752 counter register (or similar low latency, high accuracy clocks) on those
6753 targets that support it. On X86, it should map to RDTSC. On Alpha, it
6754 should map to RPCC. As the backing counters overflow quickly (on the order
6755 of 9 seconds on alpha), this should only be used for small timings.</p>
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]6756
6757<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6758<p>When directly supported, reading the cycle counter should not modify any
6759 memory. Implementations are allowed to either return a application specific
6760 value or a system wide value. On backends without support, this is lowered
6761 to a constant 0.</p>
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]6762
6763</div>
6764
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6765</div>
6766
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6767<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6768<h3>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6769 <a name="int_libc">Standard C Library Intrinsics</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6770</h3>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6771
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6772<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6773
6774<p>LLVM provides intrinsics for a few important standard C library functions.
6775 These intrinsics allow source-language front-ends to pass information about
6776 the alignment of the pointer arguments to the code generator, providing
6777 opportunity for more efficient code generation.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6778
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6779<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6780<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6781 <a name="int_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6782</h4>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6783
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6784<div>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6785
6786<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6787<p>This is an overloaded intrinsic. You can use <tt>llvm.memcpy</tt> on any
Mon P Wang508127b2010-04-07 06:35:53 +0000[diff] [blame]6788 integer bit width and for different address spaces. Not all targets support
6789 all bit widths however.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6790
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6791<pre>
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]6792 declare void @llvm.memcpy.p0i8.p0i8.i32(i8* &lt;dest&gt;, i8* &lt;src&gt;,
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6793 i32 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]6794 declare void @llvm.memcpy.p0i8.p0i8.i64(i8* &lt;dest&gt;, i8* &lt;src&gt;,
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6795 i64 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6796</pre>
6797
6798<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6799<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
6800 source location to the destination location.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6801
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6802<p>Note that, unlike the standard libc function, the <tt>llvm.memcpy.*</tt>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6803 intrinsics do not return a value, takes extra alignment/isvolatile arguments
6804 and the pointers can be in specified address spaces.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6805
6806<h5>Arguments:</h5>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6807
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6808<p>The first argument is a pointer to the destination, the second is a pointer
6809 to the source. The third argument is an integer argument specifying the
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6810 number of bytes to copy, the fourth argument is the alignment of the
6811 source and destination locations, and the fifth is a boolean indicating a
6812 volatile access.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6813
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]6814<p>If the call to this intrinsic has an alignment value that is not 0 or 1,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6815 then the caller guarantees that both the source and destination pointers are
6816 aligned to that boundary.</p>
Chris Lattner4c67c482004-02-12 21:18:15 +0000[diff] [blame]6817
Jeffrey Yasskin5d284ae2010-04-26 21:21:24 +0000[diff] [blame]6818<p>If the <tt>isvolatile</tt> parameter is <tt>true</tt>, the
6819 <tt>llvm.memcpy</tt> call is a <a href="#volatile">volatile operation</a>.
6820 The detailed access behavior is not very cleanly specified and it is unwise
6821 to depend on it.</p>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6822
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6823<h5>Semantics:</h5>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6824
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6825<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
6826 source location to the destination location, which are not allowed to
6827 overlap. It copies "len" bytes of memory over. If the argument is known to
6828 be aligned to some boundary, this can be specified as the fourth argument,
6829 otherwise it should be set to 0 or 1.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6830
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6831</div>
6832
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6833<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6834<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6835 <a name="int_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6836</h4>
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6837
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6838<div>
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6839
6840<h5>Syntax:</h5>
Chris Lattnerdd708342008-11-21 16:42:48 +0000[diff] [blame]6841<p>This is an overloaded intrinsic. You can use llvm.memmove on any integer bit
Mon P Wang508127b2010-04-07 06:35:53 +0000[diff] [blame]6842 width and for different address space. Not all targets support all bit
6843 widths however.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6844
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6845<pre>
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]6846 declare void @llvm.memmove.p0i8.p0i8.i32(i8* &lt;dest&gt;, i8* &lt;src&gt;,
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6847 i32 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]6848 declare void @llvm.memmove.p0i8.p0i8.i64(i8* &lt;dest&gt;, i8* &lt;src&gt;,
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6849 i64 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6850</pre>
6851
6852<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6853<p>The '<tt>llvm.memmove.*</tt>' intrinsics move a block of memory from the
6854 source location to the destination location. It is similar to the
6855 '<tt>llvm.memcpy</tt>' intrinsic but allows the two memory locations to
6856 overlap.</p>
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6857
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6858<p>Note that, unlike the standard libc function, the <tt>llvm.memmove.*</tt>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6859 intrinsics do not return a value, takes extra alignment/isvolatile arguments
6860 and the pointers can be in specified address spaces.</p>
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6861
6862<h5>Arguments:</h5>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6863
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6864<p>The first argument is a pointer to the destination, the second is a pointer
6865 to the source. The third argument is an integer argument specifying the
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6866 number of bytes to copy, the fourth argument is the alignment of the
6867 source and destination locations, and the fifth is a boolean indicating a
6868 volatile access.</p>
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6869
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]6870<p>If the call to this intrinsic has an alignment value that is not 0 or 1,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6871 then the caller guarantees that the source and destination pointers are
6872 aligned to that boundary.</p>
Chris Lattner4c67c482004-02-12 21:18:15 +0000[diff] [blame]6873
Jeffrey Yasskin5d284ae2010-04-26 21:21:24 +0000[diff] [blame]6874<p>If the <tt>isvolatile</tt> parameter is <tt>true</tt>, the
6875 <tt>llvm.memmove</tt> call is a <a href="#volatile">volatile operation</a>.
6876 The detailed access behavior is not very cleanly specified and it is unwise
6877 to depend on it.</p>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6878
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6879<h5>Semantics:</h5>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6880
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6881<p>The '<tt>llvm.memmove.*</tt>' intrinsics copy a block of memory from the
6882 source location to the destination location, which may overlap. It copies
6883 "len" bytes of memory over. If the argument is known to be aligned to some
6884 boundary, this can be specified as the fourth argument, otherwise it should
6885 be set to 0 or 1.</p>
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6886
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6887</div>
6888
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6889<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6890<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6891 <a name="int_memset">'<tt>llvm.memset.*</tt>' Intrinsics</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6892</h4>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6893
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6894<div>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6895
6896<h5>Syntax:</h5>
Chris Lattnerdd708342008-11-21 16:42:48 +0000[diff] [blame]6897<p>This is an overloaded intrinsic. You can use llvm.memset on any integer bit
John Criswellad05ae42010-07-30 16:30:28 +0000[diff] [blame]6898 width and for different address spaces. However, not all targets support all
6899 bit widths.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6900
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6901<pre>
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]6902 declare void @llvm.memset.p0i8.i32(i8* &lt;dest&gt;, i8 &lt;val&gt;,
Chris Lattner685db9d2010-04-08 00:54:34 +0000[diff] [blame]6903 i32 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]6904 declare void @llvm.memset.p0i8.i64(i8* &lt;dest&gt;, i8 &lt;val&gt;,
Chris Lattner685db9d2010-04-08 00:54:34 +0000[diff] [blame]6905 i64 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6906</pre>
6907
6908<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6909<p>The '<tt>llvm.memset.*</tt>' intrinsics fill a block of memory with a
6910 particular byte value.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6911
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6912<p>Note that, unlike the standard libc function, the <tt>llvm.memset</tt>
John Criswellad05ae42010-07-30 16:30:28 +0000[diff] [blame]6913 intrinsic does not return a value and takes extra alignment/volatile
6914 arguments. Also, the destination can be in an arbitrary address space.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6915
6916<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6917<p>The first argument is a pointer to the destination to fill, the second is the
John Criswellad05ae42010-07-30 16:30:28 +0000[diff] [blame]6918 byte value with which to fill it, the third argument is an integer argument
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6919 specifying the number of bytes to fill, and the fourth argument is the known
John Criswellad05ae42010-07-30 16:30:28 +0000[diff] [blame]6920 alignment of the destination location.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6921
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]6922<p>If the call to this intrinsic has an alignment value that is not 0 or 1,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6923 then the caller guarantees that the destination pointer is aligned to that
6924 boundary.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6925
Jeffrey Yasskin5d284ae2010-04-26 21:21:24 +0000[diff] [blame]6926<p>If the <tt>isvolatile</tt> parameter is <tt>true</tt>, the
6927 <tt>llvm.memset</tt> call is a <a href="#volatile">volatile operation</a>.
6928 The detailed access behavior is not very cleanly specified and it is unwise
6929 to depend on it.</p>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6930
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6931<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6932<p>The '<tt>llvm.memset.*</tt>' intrinsics fill "len" bytes of memory starting
6933 at the destination location. If the argument is known to be aligned to some
6934 boundary, this can be specified as the fourth argument, otherwise it should
6935 be set to 0 or 1.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6936
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6937</div>
6938
Chris Lattner3b4f4372004-06-11 02:28:03 +0000[diff] [blame]6939<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6940<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6941 <a name="int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6942</h4>
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]6943
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6944<div>
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]6945
6946<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6947<p>This is an overloaded intrinsic. You can use <tt>llvm.sqrt</tt> on any
6948 floating point or vector of floating point type. Not all targets support all
6949 types however.</p>
6950
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]6951<pre>
Dale Johannesendd89d272007-10-02 17:47:38 +0000[diff] [blame]6952 declare float @llvm.sqrt.f32(float %Val)
6953 declare double @llvm.sqrt.f64(double %Val)
6954 declare x86_fp80 @llvm.sqrt.f80(x86_fp80 %Val)
6955 declare fp128 @llvm.sqrt.f128(fp128 %Val)
6956 declare ppc_fp128 @llvm.sqrt.ppcf128(ppc_fp128 %Val)
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]6957</pre>
6958
6959<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6960<p>The '<tt>llvm.sqrt</tt>' intrinsics return the sqrt of the specified operand,
6961 returning the same value as the libm '<tt>sqrt</tt>' functions would.
6962 Unlike <tt>sqrt</tt> in libm, however, <tt>llvm.sqrt</tt> has undefined
6963 behavior for negative numbers other than -0.0 (which allows for better
6964 optimization, because there is no need to worry about errno being
6965 set). <tt>llvm.sqrt(-0.0)</tt> is defined to return -0.0 like IEEE sqrt.</p>
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]6966
6967<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6968<p>The argument and return value are floating point numbers of the same
6969 type.</p>
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]6970
6971<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6972<p>This function returns the sqrt of the specified operand if it is a
6973 nonnegative floating point number.</p>
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]6974
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]6975</div>
6976
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]6977<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6978<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6979 <a name="int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6980</h4>
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]6981
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6982<div>
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]6983
6984<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6985<p>This is an overloaded intrinsic. You can use <tt>llvm.powi</tt> on any
6986 floating point or vector of floating point type. Not all targets support all
6987 types however.</p>
6988
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]6989<pre>
Dale Johannesendd89d272007-10-02 17:47:38 +0000[diff] [blame]6990 declare float @llvm.powi.f32(float %Val, i32 %power)
6991 declare double @llvm.powi.f64(double %Val, i32 %power)
6992 declare x86_fp80 @llvm.powi.f80(x86_fp80 %Val, i32 %power)
6993 declare fp128 @llvm.powi.f128(fp128 %Val, i32 %power)
6994 declare ppc_fp128 @llvm.powi.ppcf128(ppc_fp128 %Val, i32 %power)
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]6995</pre>
6996
6997<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6998<p>The '<tt>llvm.powi.*</tt>' intrinsics return the first operand raised to the
6999 specified (positive or negative) power. The order of evaluation of
7000 multiplications is not defined. When a vector of floating point type is
7001 used, the second argument remains a scalar integer value.</p>
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]7002
7003<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7004<p>The second argument is an integer power, and the first is a value to raise to
7005 that power.</p>
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]7006
7007<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7008<p>This function returns the first value raised to the second power with an
7009 unspecified sequence of rounding operations.</p>
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]7010
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]7011</div>
7012
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]7013<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7014<h4>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]7015 <a name="int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7016</h4>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]7017
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7018<div>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]7019
7020<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7021<p>This is an overloaded intrinsic. You can use <tt>llvm.sin</tt> on any
7022 floating point or vector of floating point type. Not all targets support all
7023 types however.</p>
7024
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]7025<pre>
7026 declare float @llvm.sin.f32(float %Val)
7027 declare double @llvm.sin.f64(double %Val)
7028 declare x86_fp80 @llvm.sin.f80(x86_fp80 %Val)
7029 declare fp128 @llvm.sin.f128(fp128 %Val)
7030 declare ppc_fp128 @llvm.sin.ppcf128(ppc_fp128 %Val)
7031</pre>
7032
7033<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7034<p>The '<tt>llvm.sin.*</tt>' intrinsics return the sine of the operand.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]7035
7036<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7037<p>The argument and return value are floating point numbers of the same
7038 type.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]7039
7040<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7041<p>This function returns the sine of the specified operand, returning the same
7042 values as the libm <tt>sin</tt> functions would, and handles error conditions
7043 in the same way.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]7044
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]7045</div>
7046
7047<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7048<h4>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]7049 <a name="int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7050</h4>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]7051
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7052<div>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]7053
7054<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7055<p>This is an overloaded intrinsic. You can use <tt>llvm.cos</tt> on any
7056 floating point or vector of floating point type. Not all targets support all
7057 types however.</p>
7058
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]7059<pre>
7060 declare float @llvm.cos.f32(float %Val)
7061 declare double @llvm.cos.f64(double %Val)
7062 declare x86_fp80 @llvm.cos.f80(x86_fp80 %Val)
7063 declare fp128 @llvm.cos.f128(fp128 %Val)
7064 declare ppc_fp128 @llvm.cos.ppcf128(ppc_fp128 %Val)
7065</pre>
7066
7067<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7068<p>The '<tt>llvm.cos.*</tt>' intrinsics return the cosine of the operand.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]7069
7070<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7071<p>The argument and return value are floating point numbers of the same
7072 type.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]7073
7074<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7075<p>This function returns the cosine of the specified operand, returning the same
7076 values as the libm <tt>cos</tt> functions would, and handles error conditions
7077 in the same way.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]7078
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]7079</div>
7080
7081<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7082<h4>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]7083 <a name="int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7084</h4>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]7085
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7086<div>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]7087
7088<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7089<p>This is an overloaded intrinsic. You can use <tt>llvm.pow</tt> on any
7090 floating point or vector of floating point type. Not all targets support all
7091 types however.</p>
7092
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]7093<pre>
7094 declare float @llvm.pow.f32(float %Val, float %Power)
7095 declare double @llvm.pow.f64(double %Val, double %Power)
7096 declare x86_fp80 @llvm.pow.f80(x86_fp80 %Val, x86_fp80 %Power)
7097 declare fp128 @llvm.pow.f128(fp128 %Val, fp128 %Power)
7098 declare ppc_fp128 @llvm.pow.ppcf128(ppc_fp128 %Val, ppc_fp128 Power)
7099</pre>
7100
7101<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7102<p>The '<tt>llvm.pow.*</tt>' intrinsics return the first operand raised to the
7103 specified (positive or negative) power.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]7104
7105<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7106<p>The second argument is a floating point power, and the first is a value to
7107 raise to that power.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]7108
7109<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7110<p>This function returns the first value raised to the second power, returning
7111 the same values as the libm <tt>pow</tt> functions would, and handles error
7112 conditions in the same way.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]7113
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]7114</div>
7115
Dan Gohman911fa902011-05-23 21:13:03 +0000[diff] [blame]7116<!-- _______________________________________________________________________ -->
7117<h4>
7118 <a name="int_exp">'<tt>llvm.exp.*</tt>' Intrinsic</a>
7119</h4>
7120
7121<div>
7122
7123<h5>Syntax:</h5>
7124<p>This is an overloaded intrinsic. You can use <tt>llvm.exp</tt> on any
7125 floating point or vector of floating point type. Not all targets support all
7126 types however.</p>
7127
7128<pre>
7129 declare float @llvm.exp.f32(float %Val)
7130 declare double @llvm.exp.f64(double %Val)
7131 declare x86_fp80 @llvm.exp.f80(x86_fp80 %Val)
7132 declare fp128 @llvm.exp.f128(fp128 %Val)
7133 declare ppc_fp128 @llvm.exp.ppcf128(ppc_fp128 %Val)
7134</pre>
7135
7136<h5>Overview:</h5>
7137<p>The '<tt>llvm.exp.*</tt>' intrinsics perform the exp function.</p>
7138
7139<h5>Arguments:</h5>
7140<p>The argument and return value are floating point numbers of the same
7141 type.</p>
7142
7143<h5>Semantics:</h5>
7144<p>This function returns the same values as the libm <tt>exp</tt> functions
7145 would, and handles error conditions in the same way.</p>
7146
7147</div>
7148
7149<!-- _______________________________________________________________________ -->
7150<h4>
7151 <a name="int_log">'<tt>llvm.log.*</tt>' Intrinsic</a>
7152</h4>
7153
7154<div>
7155
7156<h5>Syntax:</h5>
7157<p>This is an overloaded intrinsic. You can use <tt>llvm.log</tt> on any
7158 floating point or vector of floating point type. Not all targets support all
7159 types however.</p>
7160
7161<pre>
7162 declare float @llvm.log.f32(float %Val)
7163 declare double @llvm.log.f64(double %Val)
7164 declare x86_fp80 @llvm.log.f80(x86_fp80 %Val)
7165 declare fp128 @llvm.log.f128(fp128 %Val)
7166 declare ppc_fp128 @llvm.log.ppcf128(ppc_fp128 %Val)
7167</pre>
7168
7169<h5>Overview:</h5>
7170<p>The '<tt>llvm.log.*</tt>' intrinsics perform the log function.</p>
7171
7172<h5>Arguments:</h5>
7173<p>The argument and return value are floating point numbers of the same
7174 type.</p>
7175
7176<h5>Semantics:</h5>
7177<p>This function returns the same values as the libm <tt>log</tt> functions
7178 would, and handles error conditions in the same way.</p>
7179
Nick Lewyckycd196f62011-10-31 01:32:21 +0000[diff] [blame]7180</div>
7181
7182<!-- _______________________________________________________________________ -->
Cameron Zwarichf03fa182011-07-08 21:39:21 +0000[diff] [blame]7183<h4>
7184 <a name="int_fma">'<tt>llvm.fma.*</tt>' Intrinsic</a>
7185</h4>
7186
7187<div>
7188
7189<h5>Syntax:</h5>
7190<p>This is an overloaded intrinsic. You can use <tt>llvm.fma</tt> on any
7191 floating point or vector of floating point type. Not all targets support all
7192 types however.</p>
7193
7194<pre>
7195 declare float @llvm.fma.f32(float %a, float %b, float %c)
7196 declare double @llvm.fma.f64(double %a, double %b, double %c)
7197 declare x86_fp80 @llvm.fma.f80(x86_fp80 %a, x86_fp80 %b, x86_fp80 %c)
7198 declare fp128 @llvm.fma.f128(fp128 %a, fp128 %b, fp128 %c)
7199 declare ppc_fp128 @llvm.fma.ppcf128(ppc_fp128 %a, ppc_fp128 %b, ppc_fp128 %c)
7200</pre>
7201
7202<h5>Overview:</h5>
Cameron Zwaricha32fd212011-07-08 22:13:55 +0000[diff] [blame]7203<p>The '<tt>llvm.fma.*</tt>' intrinsics perform the fused multiply-add
Cameron Zwarichf03fa182011-07-08 21:39:21 +0000[diff] [blame]7204 operation.</p>
7205
7206<h5>Arguments:</h5>
7207<p>The argument and return value are floating point numbers of the same
7208 type.</p>
7209
7210<h5>Semantics:</h5>
7211<p>This function returns the same values as the libm <tt>fma</tt> functions
7212 would.</p>
7213
Dan Gohman911fa902011-05-23 21:13:03 +0000[diff] [blame]7214</div>
7215
NAKAMURA Takumia35cdd62011-10-31 13:04:26 +0000[diff] [blame]7216</div>
7217
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7218<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7219<h3>
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]7220 <a name="int_manip">Bit Manipulation Intrinsics</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7221</h3>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7222
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7223<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7224
7225<p>LLVM provides intrinsics for a few important bit manipulation operations.
7226 These allow efficient code generation for some algorithms.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7227
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7228<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7229<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]7230 <a name="int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7231</h4>
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]7232
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7233<div>
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]7234
7235<h5>Syntax:</h5>
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]7236<p>This is an overloaded intrinsic function. You can use bswap on any integer
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7237 type that is an even number of bytes (i.e. BitWidth % 16 == 0).</p>
7238
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]7239<pre>
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]7240 declare i16 @llvm.bswap.i16(i16 &lt;id&gt;)
7241 declare i32 @llvm.bswap.i32(i32 &lt;id&gt;)
7242 declare i64 @llvm.bswap.i64(i64 &lt;id&gt;)
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]7243</pre>
7244
7245<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7246<p>The '<tt>llvm.bswap</tt>' family of intrinsics is used to byte swap integer
7247 values with an even number of bytes (positive multiple of 16 bits). These
7248 are useful for performing operations on data that is not in the target's
7249 native byte order.</p>
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]7250
7251<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7252<p>The <tt>llvm.bswap.i16</tt> intrinsic returns an i16 value that has the high
7253 and low byte of the input i16 swapped. Similarly,
7254 the <tt>llvm.bswap.i32</tt> intrinsic returns an i32 value that has the four
7255 bytes of the input i32 swapped, so that if the input bytes are numbered 0, 1,
7256 2, 3 then the returned i32 will have its bytes in 3, 2, 1, 0 order.
7257 The <tt>llvm.bswap.i48</tt>, <tt>llvm.bswap.i64</tt> and other intrinsics
7258 extend this concept to additional even-byte lengths (6 bytes, 8 bytes and
7259 more, respectively).</p>
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]7260
7261</div>
7262
7263<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7264<h4>
Reid Spencerb4f9a6f2006-01-16 21:12:35 +0000[diff] [blame]7265 <a name="int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7266</h4>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7267
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7268<div>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7269
7270<h5>Syntax:</h5>
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]7271<p>This is an overloaded intrinsic. You can use llvm.ctpop on any integer bit
Owen Anderson2f37bdc2011-07-01 21:52:38 +0000[diff] [blame]7272 width, or on any vector with integer elements. Not all targets support all
7273 bit widths or vector types, however.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7274
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7275<pre>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7276 declare i8 @llvm.ctpop.i8(i8 &lt;src&gt;)
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]7277 declare i16 @llvm.ctpop.i16(i16 &lt;src&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]7278 declare i32 @llvm.ctpop.i32(i32 &lt;src&gt;)
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]7279 declare i64 @llvm.ctpop.i64(i64 &lt;src&gt;)
7280 declare i256 @llvm.ctpop.i256(i256 &lt;src&gt;)
Owen Anderson2f37bdc2011-07-01 21:52:38 +0000[diff] [blame]7281 declare &lt;2 x i32&gt; @llvm.ctpop.v2i32(&lt;2 x i32&gt; &lt;src&gt;)
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7282</pre>
7283
7284<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7285<p>The '<tt>llvm.ctpop</tt>' family of intrinsics counts the number of bits set
7286 in a value.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7287
7288<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7289<p>The only argument is the value to be counted. The argument may be of any
Owen Anderson2f37bdc2011-07-01 21:52:38 +0000[diff] [blame]7290 integer type, or a vector with integer elements.
7291 The return type must match the argument type.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7292
7293<h5>Semantics:</h5>
Owen Anderson2f37bdc2011-07-01 21:52:38 +0000[diff] [blame]7294<p>The '<tt>llvm.ctpop</tt>' intrinsic counts the 1's in a variable, or within each
7295 element of a vector.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7296
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7297</div>
7298
7299<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7300<h4>
Chris Lattnerb748c672006-01-16 22:34:14 +0000[diff] [blame]7301 <a name="int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7302</h4>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7303
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7304<div>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7305
7306<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7307<p>This is an overloaded intrinsic. You can use <tt>llvm.ctlz</tt> on any
Owen Anderson2f37bdc2011-07-01 21:52:38 +0000[diff] [blame]7308 integer bit width, or any vector whose elements are integers. Not all
7309 targets support all bit widths or vector types, however.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7310
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7311<pre>
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]7312 declare i8 @llvm.ctlz.i8 (i8 &lt;src&gt;)
7313 declare i16 @llvm.ctlz.i16(i16 &lt;src&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]7314 declare i32 @llvm.ctlz.i32(i32 &lt;src&gt;)
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]7315 declare i64 @llvm.ctlz.i64(i64 &lt;src&gt;)
7316 declare i256 @llvm.ctlz.i256(i256 &lt;src&gt;)
Owen Anderson2f37bdc2011-07-01 21:52:38 +0000[diff] [blame]7317 declare &lt;2 x i32&gt; @llvm.ctlz.v2i32(&lt;2 x i32&gt; &lt;src;gt)
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7318</pre>
7319
7320<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7321<p>The '<tt>llvm.ctlz</tt>' family of intrinsic functions counts the number of
7322 leading zeros in a variable.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7323
7324<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7325<p>The only argument is the value to be counted. The argument may be of any
Owen Anderson2f37bdc2011-07-01 21:52:38 +0000[diff] [blame]7326 integer type, or any vector type with integer element type.
7327 The return type must match the argument type.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7328
7329<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7330<p>The '<tt>llvm.ctlz</tt>' intrinsic counts the leading (most significant)
Owen Anderson2f37bdc2011-07-01 21:52:38 +0000[diff] [blame]7331 zeros in a variable, or within each element of the vector if the operation
7332 is of vector type. If the src == 0 then the result is the size in bits of
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7333 the type of src. For example, <tt>llvm.ctlz(i32 2) = 30</tt>.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7334
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7335</div>
Chris Lattner3b4f4372004-06-11 02:28:03 +0000[diff] [blame]7336
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]7337<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7338<h4>
Chris Lattnerb748c672006-01-16 22:34:14 +0000[diff] [blame]7339 <a name="int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7340</h4>
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]7341
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7342<div>
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]7343
7344<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7345<p>This is an overloaded intrinsic. You can use <tt>llvm.cttz</tt> on any
Owen Anderson2f37bdc2011-07-01 21:52:38 +0000[diff] [blame]7346 integer bit width, or any vector of integer elements. Not all targets
7347 support all bit widths or vector types, however.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7348
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]7349<pre>
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]7350 declare i8 @llvm.cttz.i8 (i8 &lt;src&gt;)
7351 declare i16 @llvm.cttz.i16(i16 &lt;src&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]7352 declare i32 @llvm.cttz.i32(i32 &lt;src&gt;)
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]7353 declare i64 @llvm.cttz.i64(i64 &lt;src&gt;)
7354 declare i256 @llvm.cttz.i256(i256 &lt;src&gt;)
Owen Anderson2f37bdc2011-07-01 21:52:38 +0000[diff] [blame]7355 declase &lt;2 x i32&gt; @llvm.cttz.v2i32(&lt;2 x i32&gt; &lt;src&gt;)
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]7356</pre>
7357
7358<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7359<p>The '<tt>llvm.cttz</tt>' family of intrinsic functions counts the number of
7360 trailing zeros.</p>
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]7361
7362<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7363<p>The only argument is the value to be counted. The argument may be of any
Owen Anderson2f37bdc2011-07-01 21:52:38 +0000[diff] [blame]7364 integer type, or a vectory with integer element type.. The return type
7365 must match the argument type.</p>
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]7366
7367<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7368<p>The '<tt>llvm.cttz</tt>' intrinsic counts the trailing (least significant)
Owen Anderson2f37bdc2011-07-01 21:52:38 +0000[diff] [blame]7369 zeros in a variable, or within each element of a vector.
7370 If the src == 0 then the result is the size in bits of
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7371 the type of src. For example, <tt>llvm.cttz(2) = 1</tt>.</p>
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]7372
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]7373</div>
7374
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7375</div>
7376
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]7377<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7378<h3>
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]7379 <a name="int_overflow">Arithmetic with Overflow Intrinsics</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7380</h3>
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]7381
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7382<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7383
7384<p>LLVM provides intrinsics for some arithmetic with overflow operations.</p>
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]7385
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7386<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7387<h4>
7388 <a name="int_sadd_overflow">
7389 '<tt>llvm.sadd.with.overflow.*</tt>' Intrinsics
7390 </a>
7391</h4>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7392
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7393<div>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7394
7395<h5>Syntax:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7396<p>This is an overloaded intrinsic. You can use <tt>llvm.sadd.with.overflow</tt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7397 on any integer bit width.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7398
7399<pre>
7400 declare {i16, i1} @llvm.sadd.with.overflow.i16(i16 %a, i16 %b)
7401 declare {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
7402 declare {i64, i1} @llvm.sadd.with.overflow.i64(i64 %a, i64 %b)
7403</pre>
7404
7405<h5>Overview:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7406<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7407 a signed addition of the two arguments, and indicate whether an overflow
7408 occurred during the signed summation.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7409
7410<h5>Arguments:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7411<p>The arguments (%a and %b) and the first element of the result structure may
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7412 be of integer types of any bit width, but they must have the same bit
7413 width. The second element of the result structure must be of
7414 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
7415 undergo signed addition.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7416
7417<h5>Semantics:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7418<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7419 a signed addition of the two variables. They return a structure &mdash; the
7420 first element of which is the signed summation, and the second element of
7421 which is a bit specifying if the signed summation resulted in an
7422 overflow.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7423
7424<h5>Examples:</h5>
7425<pre>
7426 %res = call {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
7427 %sum = extractvalue {i32, i1} %res, 0
7428 %obit = extractvalue {i32, i1} %res, 1
7429 br i1 %obit, label %overflow, label %normal
7430</pre>
7431
7432</div>
7433
7434<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7435<h4>
7436 <a name="int_uadd_overflow">
7437 '<tt>llvm.uadd.with.overflow.*</tt>' Intrinsics
7438 </a>
7439</h4>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7440
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7441<div>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7442
7443<h5>Syntax:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7444<p>This is an overloaded intrinsic. You can use <tt>llvm.uadd.with.overflow</tt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7445 on any integer bit width.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7446
7447<pre>
7448 declare {i16, i1} @llvm.uadd.with.overflow.i16(i16 %a, i16 %b)
7449 declare {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
7450 declare {i64, i1} @llvm.uadd.with.overflow.i64(i64 %a, i64 %b)
7451</pre>
7452
7453<h5>Overview:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7454<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7455 an unsigned addition of the two arguments, and indicate whether a carry
7456 occurred during the unsigned summation.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7457
7458<h5>Arguments:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7459<p>The arguments (%a and %b) and the first element of the result structure may
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7460 be of integer types of any bit width, but they must have the same bit
7461 width. The second element of the result structure must be of
7462 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
7463 undergo unsigned addition.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7464
7465<h5>Semantics:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7466<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7467 an unsigned addition of the two arguments. They return a structure &mdash;
7468 the first element of which is the sum, and the second element of which is a
7469 bit specifying if the unsigned summation resulted in a carry.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7470
7471<h5>Examples:</h5>
7472<pre>
7473 %res = call {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
7474 %sum = extractvalue {i32, i1} %res, 0
7475 %obit = extractvalue {i32, i1} %res, 1
7476 br i1 %obit, label %carry, label %normal
7477</pre>
7478
7479</div>
7480
7481<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7482<h4>
7483 <a name="int_ssub_overflow">
7484 '<tt>llvm.ssub.with.overflow.*</tt>' Intrinsics
7485 </a>
7486</h4>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7487
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7488<div>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7489
7490<h5>Syntax:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7491<p>This is an overloaded intrinsic. You can use <tt>llvm.ssub.with.overflow</tt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7492 on any integer bit width.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7493
7494<pre>
7495 declare {i16, i1} @llvm.ssub.with.overflow.i16(i16 %a, i16 %b)
7496 declare {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
7497 declare {i64, i1} @llvm.ssub.with.overflow.i64(i64 %a, i64 %b)
7498</pre>
7499
7500<h5>Overview:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7501<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7502 a signed subtraction of the two arguments, and indicate whether an overflow
7503 occurred during the signed subtraction.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7504
7505<h5>Arguments:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7506<p>The arguments (%a and %b) and the first element of the result structure may
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7507 be of integer types of any bit width, but they must have the same bit
7508 width. The second element of the result structure must be of
7509 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
7510 undergo signed subtraction.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7511
7512<h5>Semantics:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7513<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7514 a signed subtraction of the two arguments. They return a structure &mdash;
7515 the first element of which is the subtraction, and the second element of
7516 which is a bit specifying if the signed subtraction resulted in an
7517 overflow.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7518
7519<h5>Examples:</h5>
7520<pre>
7521 %res = call {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
7522 %sum = extractvalue {i32, i1} %res, 0
7523 %obit = extractvalue {i32, i1} %res, 1
7524 br i1 %obit, label %overflow, label %normal
7525</pre>
7526
7527</div>
7528
7529<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7530<h4>
7531 <a name="int_usub_overflow">
7532 '<tt>llvm.usub.with.overflow.*</tt>' Intrinsics
7533 </a>
7534</h4>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7535
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7536<div>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7537
7538<h5>Syntax:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7539<p>This is an overloaded intrinsic. You can use <tt>llvm.usub.with.overflow</tt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7540 on any integer bit width.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7541
7542<pre>
7543 declare {i16, i1} @llvm.usub.with.overflow.i16(i16 %a, i16 %b)
7544 declare {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
7545 declare {i64, i1} @llvm.usub.with.overflow.i64(i64 %a, i64 %b)
7546</pre>
7547
7548<h5>Overview:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7549<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7550 an unsigned subtraction of the two arguments, and indicate whether an
7551 overflow occurred during the unsigned subtraction.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7552
7553<h5>Arguments:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7554<p>The arguments (%a and %b) and the first element of the result structure may
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7555 be of integer types of any bit width, but they must have the same bit
7556 width. The second element of the result structure must be of
7557 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
7558 undergo unsigned subtraction.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7559
7560<h5>Semantics:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7561<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7562 an unsigned subtraction of the two arguments. They return a structure &mdash;
7563 the first element of which is the subtraction, and the second element of
7564 which is a bit specifying if the unsigned subtraction resulted in an
7565 overflow.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7566
7567<h5>Examples:</h5>
7568<pre>
7569 %res = call {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
7570 %sum = extractvalue {i32, i1} %res, 0
7571 %obit = extractvalue {i32, i1} %res, 1
7572 br i1 %obit, label %overflow, label %normal
7573</pre>
7574
7575</div>
7576
7577<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7578<h4>
7579 <a name="int_smul_overflow">
7580 '<tt>llvm.smul.with.overflow.*</tt>' Intrinsics
7581 </a>
7582</h4>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7583
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7584<div>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7585
7586<h5>Syntax:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7587<p>This is an overloaded intrinsic. You can use <tt>llvm.smul.with.overflow</tt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7588 on any integer bit width.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7589
7590<pre>
7591 declare {i16, i1} @llvm.smul.with.overflow.i16(i16 %a, i16 %b)
7592 declare {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
7593 declare {i64, i1} @llvm.smul.with.overflow.i64(i64 %a, i64 %b)
7594</pre>
7595
7596<h5>Overview:</h5>
7597
7598<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7599 a signed multiplication of the two arguments, and indicate whether an
7600 overflow occurred during the signed multiplication.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7601
7602<h5>Arguments:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7603<p>The arguments (%a and %b) and the first element of the result structure may
Bill Wendlingd9a66f72009-07-20 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 signed multiplication.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7608
7609<h5>Semantics:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7610<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7611 a signed multiplication of the two arguments. They return a structure &mdash;
7612 the first element of which is the multiplication, and the second element of
7613 which is a bit specifying if the signed multiplication resulted in an
7614 overflow.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7615
7616<h5>Examples:</h5>
7617<pre>
7618 %res = call {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
7619 %sum = extractvalue {i32, i1} %res, 0
7620 %obit = extractvalue {i32, i1} %res, 1
7621 br i1 %obit, label %overflow, label %normal
7622</pre>
7623
Reid Spencer5bf54c82007-04-11 23:23:49 +0000[diff] [blame]7624</div>
7625
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]7626<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7627<h4>
7628 <a name="int_umul_overflow">
7629 '<tt>llvm.umul.with.overflow.*</tt>' Intrinsics
7630 </a>
7631</h4>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]7632
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7633<div>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]7634
7635<h5>Syntax:</h5>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]7636<p>This is an overloaded intrinsic. You can use <tt>llvm.umul.with.overflow</tt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7637 on any integer bit width.</p>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]7638
7639<pre>
7640 declare {i16, i1} @llvm.umul.with.overflow.i16(i16 %a, i16 %b)
7641 declare {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
7642 declare {i64, i1} @llvm.umul.with.overflow.i64(i64 %a, i64 %b)
7643</pre>
7644
7645<h5>Overview:</h5>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]7646<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7647 a unsigned multiplication of the two arguments, and indicate whether an
7648 overflow occurred during the unsigned multiplication.</p>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]7649
7650<h5>Arguments:</h5>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]7651<p>The arguments (%a and %b) and the first element of the result structure may
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7652 be of integer types of any bit width, but they must have the same bit
7653 width. The second element of the result structure must be of
7654 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
7655 undergo unsigned multiplication.</p>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]7656
7657<h5>Semantics:</h5>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]7658<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7659 an unsigned multiplication of the two arguments. They return a structure
7660 &mdash; the first element of which is the multiplication, and the second
7661 element of which is a bit specifying if the unsigned multiplication resulted
7662 in an overflow.</p>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]7663
7664<h5>Examples:</h5>
7665<pre>
7666 %res = call {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
7667 %sum = extractvalue {i32, i1} %res, 0
7668 %obit = extractvalue {i32, i1} %res, 1
7669 br i1 %obit, label %overflow, label %normal
7670</pre>
7671
7672</div>
7673
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7674</div>
7675
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]7676<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7677<h3>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]7678 <a name="int_fp16">Half Precision Floating Point Intrinsics</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7679</h3>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]7680
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7681<div>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]7682
Chris Lattner022a9fb2010-03-15 04:12:21 +0000[diff] [blame]7683<p>Half precision floating point is a storage-only format. This means that it is
7684 a dense encoding (in memory) but does not support computation in the
7685 format.</p>
Chris Lattnerbbd8bd32010-03-14 23:03:31 +0000[diff] [blame]7686
Chris Lattner022a9fb2010-03-15 04:12:21 +0000[diff] [blame]7687<p>This means that code must first load the half-precision floating point
Chris Lattnerbbd8bd32010-03-14 23:03:31 +0000[diff] [blame]7688 value as an i16, then convert it to float with <a
7689 href="#int_convert_from_fp16"><tt>llvm.convert.from.fp16</tt></a>.
7690 Computation can then be performed on the float value (including extending to
Chris Lattner022a9fb2010-03-15 04:12:21 +0000[diff] [blame]7691 double etc). To store the value back to memory, it is first converted to
7692 float if needed, then converted to i16 with
Chris Lattnerbbd8bd32010-03-14 23:03:31 +0000[diff] [blame]7693 <a href="#int_convert_to_fp16"><tt>llvm.convert.to.fp16</tt></a>, then
7694 storing as an i16 value.</p>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]7695
7696<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7697<h4>
7698 <a name="int_convert_to_fp16">
7699 '<tt>llvm.convert.to.fp16</tt>' Intrinsic
7700 </a>
7701</h4>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]7702
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7703<div>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]7704
7705<h5>Syntax:</h5>
7706<pre>
7707 declare i16 @llvm.convert.to.fp16(f32 %a)
7708</pre>
7709
7710<h5>Overview:</h5>
7711<p>The '<tt>llvm.convert.to.fp16</tt>' intrinsic function performs
7712 a conversion from single precision floating point format to half precision
7713 floating point format.</p>
7714
7715<h5>Arguments:</h5>
7716<p>The intrinsic function contains single argument - the value to be
7717 converted.</p>
7718
7719<h5>Semantics:</h5>
7720<p>The '<tt>llvm.convert.to.fp16</tt>' intrinsic function performs
7721 a conversion from single precision floating point format to half precision
Chris Lattner022a9fb2010-03-15 04:12:21 +0000[diff] [blame]7722 floating point format. The return value is an <tt>i16</tt> which
Chris Lattnerbbd8bd32010-03-14 23:03:31 +0000[diff] [blame]7723 contains the converted number.</p>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]7724
7725<h5>Examples:</h5>
7726<pre>
7727 %res = call i16 @llvm.convert.to.fp16(f32 %a)
7728 store i16 %res, i16* @x, align 2
7729</pre>
7730
7731</div>
7732
7733<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7734<h4>
7735 <a name="int_convert_from_fp16">
7736 '<tt>llvm.convert.from.fp16</tt>' Intrinsic
7737 </a>
7738</h4>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]7739
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7740<div>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]7741
7742<h5>Syntax:</h5>
7743<pre>
7744 declare f32 @llvm.convert.from.fp16(i16 %a)
7745</pre>
7746
7747<h5>Overview:</h5>
7748<p>The '<tt>llvm.convert.from.fp16</tt>' intrinsic function performs
7749 a conversion from half precision floating point format to single precision
7750 floating point format.</p>
7751
7752<h5>Arguments:</h5>
7753<p>The intrinsic function contains single argument - the value to be
7754 converted.</p>
7755
7756<h5>Semantics:</h5>
7757<p>The '<tt>llvm.convert.from.fp16</tt>' intrinsic function performs a
Chris Lattner022a9fb2010-03-15 04:12:21 +0000[diff] [blame]7758 conversion from half single precision floating point format to single
Chris Lattnerbbd8bd32010-03-14 23:03:31 +0000[diff] [blame]7759 precision floating point format. The input half-float value is represented by
7760 an <tt>i16</tt> value.</p>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]7761
7762<h5>Examples:</h5>
7763<pre>
7764 %a = load i16* @x, align 2
7765 %res = call f32 @llvm.convert.from.fp16(i16 %a)
7766</pre>
7767
7768</div>
7769
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7770</div>
7771
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]7772<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7773<h3>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]7774 <a name="int_debugger">Debugger Intrinsics</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7775</h3>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]7776
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7777<div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]7778
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7779<p>The LLVM debugger intrinsics (which all start with <tt>llvm.dbg.</tt>
7780 prefix), are described in
7781 the <a href="SourceLevelDebugging.html#format_common_intrinsics">LLVM Source
7782 Level Debugging</a> document.</p>
7783
7784</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]7785
Jim Laskey2211f492007-03-14 19:31:19 +0000[diff] [blame]7786<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7787<h3>
Jim Laskey2211f492007-03-14 19:31:19 +0000[diff] [blame]7788 <a name="int_eh">Exception Handling Intrinsics</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7789</h3>
Jim Laskey2211f492007-03-14 19:31:19 +0000[diff] [blame]7790
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7791<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7792
7793<p>The LLVM exception handling intrinsics (which all start with
7794 <tt>llvm.eh.</tt> prefix), are described in
7795 the <a href="ExceptionHandling.html#format_common_intrinsics">LLVM Exception
7796 Handling</a> document.</p>
7797
Jim Laskey2211f492007-03-14 19:31:19 +0000[diff] [blame]7798</div>
7799
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]7800<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7801<h3>
Duncan Sandsa0984362011-09-06 13:37:06 +0000[diff] [blame]7802 <a name="int_trampoline">Trampoline Intrinsics</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7803</h3>
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]7804
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7805<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7806
Duncan Sandsa0984362011-09-06 13:37:06 +0000[diff] [blame]7807<p>These intrinsics make it possible to excise one parameter, marked with
Dan Gohman3770af52010-07-02 23:18:08 +0000[diff] [blame]7808 the <a href="#nest"><tt>nest</tt></a> attribute, from a function.
7809 The result is a callable
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7810 function pointer lacking the nest parameter - the caller does not need to
7811 provide a value for it. Instead, the value to use is stored in advance in a
7812 "trampoline", a block of memory usually allocated on the stack, which also
7813 contains code to splice the nest value into the argument list. This is used
7814 to implement the GCC nested function address extension.</p>
7815
7816<p>For example, if the function is
7817 <tt>i32 f(i8* nest %c, i32 %x, i32 %y)</tt> then the resulting function
7818 pointer has signature <tt>i32 (i32, i32)*</tt>. It can be created as
7819 follows:</p>
7820
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]7821<pre class="doc_code">
Duncan Sands86e01192007-09-11 14:10:23 +0000[diff] [blame]7822 %tramp = alloca [10 x i8], align 4 ; size and alignment only correct for X86
7823 %tramp1 = getelementptr [10 x i8]* %tramp, i32 0, i32 0
Duncan Sandsa0984362011-09-06 13:37:06 +0000[diff] [blame]7824 call i8* @llvm.init.trampoline(i8* %tramp1, i8* bitcast (i32 (i8*, i32, i32)* @f to i8*), i8* %nval)
7825 %p = call i8* @llvm.adjust.trampoline(i8* %tramp1)
Duncan Sands86e01192007-09-11 14:10:23 +0000[diff] [blame]7826 %fp = bitcast i8* %p to i32 (i32, i32)*
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]7827</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7828
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7829<p>The call <tt>%val = call i32 %fp(i32 %x, i32 %y)</tt> is then equivalent
7830 to <tt>%val = call i32 %f(i8* %nval, i32 %x, i32 %y)</tt>.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7831
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]7832<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7833<h4>
7834 <a name="int_it">
7835 '<tt>llvm.init.trampoline</tt>' Intrinsic
7836 </a>
7837</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7838
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7839<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7840
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]7841<h5>Syntax:</h5>
7842<pre>
Duncan Sandsa0984362011-09-06 13:37:06 +0000[diff] [blame]7843 declare void @llvm.init.trampoline(i8* &lt;tramp&gt;, i8* &lt;func&gt;, i8* &lt;nval&gt;)
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]7844</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7845
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]7846<h5>Overview:</h5>
Duncan Sandsa0984362011-09-06 13:37:06 +0000[diff] [blame]7847<p>This fills the memory pointed to by <tt>tramp</tt> with executable code,
7848 turning it into a trampoline.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7849
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]7850<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7851<p>The <tt>llvm.init.trampoline</tt> intrinsic takes three arguments, all
7852 pointers. The <tt>tramp</tt> argument must point to a sufficiently large and
7853 sufficiently aligned block of memory; this memory is written to by the
7854 intrinsic. Note that the size and the alignment are target-specific - LLVM
7855 currently provides no portable way of determining them, so a front-end that
7856 generates this intrinsic needs to have some target-specific knowledge.
7857 The <tt>func</tt> argument must hold a function bitcast to
7858 an <tt>i8*</tt>.</p>
7859
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]7860<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7861<p>The block of memory pointed to by <tt>tramp</tt> is filled with target
Duncan Sandsa0984362011-09-06 13:37:06 +0000[diff] [blame]7862 dependent code, turning it into a function. Then <tt>tramp</tt> needs to be
7863 passed to <a href="#int_at">llvm.adjust.trampoline</a> to get a pointer
7864 which can be <a href="#int_trampoline">bitcast (to a new function) and
7865 called</a>. The new function's signature is the same as that of
7866 <tt>func</tt> with any arguments marked with the <tt>nest</tt> attribute
7867 removed. At most one such <tt>nest</tt> argument is allowed, and it must be of
7868 pointer type. Calling the new function is equivalent to calling <tt>func</tt>
7869 with the same argument list, but with <tt>nval</tt> used for the missing
7870 <tt>nest</tt> argument. If, after calling <tt>llvm.init.trampoline</tt>, the
7871 memory pointed to by <tt>tramp</tt> is modified, then the effect of any later call
7872 to the returned function pointer is undefined.</p>
7873</div>
7874
7875<!-- _______________________________________________________________________ -->
7876<h4>
7877 <a name="int_at">
7878 '<tt>llvm.adjust.trampoline</tt>' Intrinsic
7879 </a>
7880</h4>
7881
7882<div>
7883
7884<h5>Syntax:</h5>
7885<pre>
7886 declare i8* @llvm.adjust.trampoline(i8* &lt;tramp&gt;)
7887</pre>
7888
7889<h5>Overview:</h5>
7890<p>This performs any required machine-specific adjustment to the address of a
7891 trampoline (passed as <tt>tramp</tt>).</p>
7892
7893<h5>Arguments:</h5>
7894<p><tt>tramp</tt> must point to a block of memory which already has trampoline code
7895 filled in by a previous call to <a href="#int_it"><tt>llvm.init.trampoline</tt>
7896 </a>.</p>
7897
7898<h5>Semantics:</h5>
7899<p>On some architectures the address of the code to be executed needs to be
7900 different to the address where the trampoline is actually stored. This
7901 intrinsic returns the executable address corresponding to <tt>tramp</tt>
7902 after performing the required machine specific adjustments.
7903 The pointer returned can then be <a href="#int_trampoline"> bitcast and
7904 executed</a>.
7905</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7906
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]7907</div>
7908
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7909</div>
7910
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]7911<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7912<h3>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]7913 <a name="int_memorymarkers">Memory Use Markers</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7914</h3>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]7915
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7916<div>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]7917
7918<p>This class of intrinsics exists to information about the lifetime of memory
7919 objects and ranges where variables are immutable.</p>
7920
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]7921<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7922<h4>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]7923 <a name="int_lifetime_start">'<tt>llvm.lifetime.start</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7924</h4>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]7925
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7926<div>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]7927
7928<h5>Syntax:</h5>
7929<pre>
7930 declare void @llvm.lifetime.start(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7931</pre>
7932
7933<h5>Overview:</h5>
7934<p>The '<tt>llvm.lifetime.start</tt>' intrinsic specifies the start of a memory
7935 object's lifetime.</p>
7936
7937<h5>Arguments:</h5>
Nick Lewycky9bc89042009-10-13 07:57:33 +0000[diff] [blame]7938<p>The first argument is a constant integer representing the size of the
7939 object, or -1 if it is variable sized. The second argument is a pointer to
7940 the object.</p>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]7941
7942<h5>Semantics:</h5>
7943<p>This intrinsic indicates that before this point in the code, the value of the
7944 memory pointed to by <tt>ptr</tt> is dead. This means that it is known to
Nick Lewyckyd20fd592009-10-27 16:56:58 +0000[diff] [blame]7945 never be used and has an undefined value. A load from the pointer that
7946 precedes this intrinsic can be replaced with
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]7947 <tt>'<a href="#undefvalues">undef</a>'</tt>.</p>
7948
7949</div>
7950
7951<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7952<h4>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]7953 <a name="int_lifetime_end">'<tt>llvm.lifetime.end</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7954</h4>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]7955
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7956<div>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]7957
7958<h5>Syntax:</h5>
7959<pre>
7960 declare void @llvm.lifetime.end(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7961</pre>
7962
7963<h5>Overview:</h5>
7964<p>The '<tt>llvm.lifetime.end</tt>' intrinsic specifies the end of a memory
7965 object's lifetime.</p>
7966
7967<h5>Arguments:</h5>
Nick Lewycky9bc89042009-10-13 07:57:33 +0000[diff] [blame]7968<p>The first argument is a constant integer representing the size of the
7969 object, or -1 if it is variable sized. The second argument is a pointer to
7970 the object.</p>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]7971
7972<h5>Semantics:</h5>
7973<p>This intrinsic indicates that after this point in the code, the value of the
7974 memory pointed to by <tt>ptr</tt> is dead. This means that it is known to
7975 never be used and has an undefined value. Any stores into the memory object
7976 following this intrinsic may be removed as dead.
7977
7978</div>
7979
7980<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7981<h4>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]7982 <a name="int_invariant_start">'<tt>llvm.invariant.start</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7983</h4>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]7984
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7985<div>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]7986
7987<h5>Syntax:</h5>
7988<pre>
Nick Lewycky2965d3e2010-11-30 04:13:41 +0000[diff] [blame]7989 declare {}* @llvm.invariant.start(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]7990</pre>
7991
7992<h5>Overview:</h5>
7993<p>The '<tt>llvm.invariant.start</tt>' intrinsic specifies that the contents of
7994 a memory object will not change.</p>
7995
7996<h5>Arguments:</h5>
Nick Lewycky9bc89042009-10-13 07:57:33 +0000[diff] [blame]7997<p>The first argument is a constant integer representing the size of the
7998 object, or -1 if it is variable sized. The second argument is a pointer to
7999 the object.</p>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]8000
8001<h5>Semantics:</h5>
8002<p>This intrinsic indicates that until an <tt>llvm.invariant.end</tt> that uses
8003 the return value, the referenced memory location is constant and
8004 unchanging.</p>
8005
8006</div>
8007
8008<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8009<h4>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]8010 <a name="int_invariant_end">'<tt>llvm.invariant.end</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8011</h4>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]8012
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]8013<div>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]8014
8015<h5>Syntax:</h5>
8016<pre>
8017 declare void @llvm.invariant.end({}* &lt;start&gt;, i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
8018</pre>
8019
8020<h5>Overview:</h5>
8021<p>The '<tt>llvm.invariant.end</tt>' intrinsic specifies that the contents of
8022 a memory object are mutable.</p>
8023
8024<h5>Arguments:</h5>
8025<p>The first argument is the matching <tt>llvm.invariant.start</tt> intrinsic.
Nick Lewycky9bc89042009-10-13 07:57:33 +0000[diff] [blame]8026 The second argument is a constant integer representing the size of the
8027 object, or -1 if it is variable sized and the third argument is a pointer
8028 to the object.</p>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]8029
8030<h5>Semantics:</h5>
8031<p>This intrinsic indicates that the memory is mutable again.</p>
8032
8033</div>
8034
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]8035</div>
8036
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]8037<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8038<h3>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]8039 <a name="int_general">General Intrinsics</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8040</h3>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]8041
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]8042<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8043
8044<p>This class of intrinsics is designed to be generic and has no specific
8045 purpose.</p>
8046
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]8047<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8048<h4>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]8049 <a name="int_var_annotation">'<tt>llvm.var.annotation</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8050</h4>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]8051
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]8052<div>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]8053
8054<h5>Syntax:</h5>
8055<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]8056 declare void @llvm.var.annotation(i8* &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]8057</pre>
8058
8059<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8060<p>The '<tt>llvm.var.annotation</tt>' intrinsic.</p>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]8061
8062<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8063<p>The first argument is a pointer to a value, the second is a pointer to a
8064 global string, the third is a pointer to a global string which is the source
8065 file name, and the last argument is the line number.</p>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]8066
8067<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8068<p>This intrinsic allows annotation of local variables with arbitrary strings.
8069 This can be useful for special purpose optimizations that want to look for
John Criswellf0d536a2011-08-19 16:57:55 +0000[diff] [blame]8070 these annotations. These have no other defined use; they are ignored by code
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8071 generation and optimization.</p>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]8072
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]8073</div>
8074
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]8075<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8076<h4>
Tanya Lattner0186a652007-09-21 23:57:59 +0000[diff] [blame]8077 <a name="int_annotation">'<tt>llvm.annotation.*</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8078</h4>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]8079
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]8080<div>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]8081
8082<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8083<p>This is an overloaded intrinsic. You can use '<tt>llvm.annotation</tt>' on
8084 any integer bit width.</p>
8085
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]8086<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]8087 declare i8 @llvm.annotation.i8(i8 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
8088 declare i16 @llvm.annotation.i16(i16 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
8089 declare i32 @llvm.annotation.i32(i32 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
8090 declare i64 @llvm.annotation.i64(i64 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
8091 declare i256 @llvm.annotation.i256(i256 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]8092</pre>
8093
8094<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8095<p>The '<tt>llvm.annotation</tt>' intrinsic.</p>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]8096
8097<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8098<p>The first argument is an integer value (result of some expression), the
8099 second is a pointer to a global string, the third is a pointer to a global
8100 string which is the source file name, and the last argument is the line
8101 number. It returns the value of the first argument.</p>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]8102
8103<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8104<p>This intrinsic allows annotations to be put on arbitrary expressions with
8105 arbitrary strings. This can be useful for special purpose optimizations that
John Criswellf0d536a2011-08-19 16:57:55 +0000[diff] [blame]8106 want to look for these annotations. These have no other defined use; they
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8107 are ignored by code generation and optimization.</p>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]8108
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]8109</div>
Jim Laskey2211f492007-03-14 19:31:19 +0000[diff] [blame]8110
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]8111<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8112<h4>
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]8113 <a name="int_trap">'<tt>llvm.trap</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8114</h4>
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]8115
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]8116<div>
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]8117
8118<h5>Syntax:</h5>
8119<pre>
8120 declare void @llvm.trap()
8121</pre>
8122
8123<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8124<p>The '<tt>llvm.trap</tt>' intrinsic.</p>
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]8125
8126<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8127<p>None.</p>
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]8128
8129<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8130<p>This intrinsics is lowered to the target dependent trap instruction. If the
8131 target does not have a trap instruction, this intrinsic will be lowered to
8132 the call of the <tt>abort()</tt> function.</p>
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]8133
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]8134</div>
8135
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]8136<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8137<h4>
Misha Brukman50de2b22008-11-22 23:55:29 +0000[diff] [blame]8138 <a name="int_stackprotector">'<tt>llvm.stackprotector</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8139</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8140
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]8141<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8142
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]8143<h5>Syntax:</h5>
8144<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]8145 declare void @llvm.stackprotector(i8* &lt;guard&gt;, i8** &lt;slot&gt;)
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]8146</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8147
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]8148<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8149<p>The <tt>llvm.stackprotector</tt> intrinsic takes the <tt>guard</tt> and
8150 stores it onto the stack at <tt>slot</tt>. The stack slot is adjusted to
8151 ensure that it is placed on the stack before local variables.</p>
8152
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]8153<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8154<p>The <tt>llvm.stackprotector</tt> intrinsic requires two pointer
8155 arguments. The first argument is the value loaded from the stack
8156 guard <tt>@__stack_chk_guard</tt>. The second variable is an <tt>alloca</tt>
8157 that has enough space to hold the value of the guard.</p>
8158
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]8159<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8160<p>This intrinsic causes the prologue/epilogue inserter to force the position of
8161 the <tt>AllocaInst</tt> stack slot to be before local variables on the
8162 stack. This is to ensure that if a local variable on the stack is
8163 overwritten, it will destroy the value of the guard. When the function exits,
Bill Wendling6bbe0912010-10-27 01:07:41 +0000[diff] [blame]8164 the guard on the stack is checked against the original guard. If they are
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8165 different, then the program aborts by calling the <tt>__stack_chk_fail()</tt>
8166 function.</p>
8167
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]8168</div>
8169
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]8170<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8171<h4>
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]8172 <a name="int_objectsize">'<tt>llvm.objectsize</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8173</h4>
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]8174
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]8175<div>
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]8176
8177<h5>Syntax:</h5>
8178<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]8179 declare i32 @llvm.objectsize.i32(i8* &lt;object&gt;, i1 &lt;type&gt;)
8180 declare i64 @llvm.objectsize.i64(i8* &lt;object&gt;, i1 &lt;type&gt;)
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]8181</pre>
8182
8183<h5>Overview:</h5>
Bill Wendling6bbe0912010-10-27 01:07:41 +0000[diff] [blame]8184<p>The <tt>llvm.objectsize</tt> intrinsic is designed to provide information to
8185 the optimizers to determine at compile time whether a) an operation (like
8186 memcpy) will overflow a buffer that corresponds to an object, or b) that a
8187 runtime check for overflow isn't necessary. An object in this context means
8188 an allocation of a specific class, structure, array, or other object.</p>
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]8189
8190<h5>Arguments:</h5>
Bill Wendling6bbe0912010-10-27 01:07:41 +0000[diff] [blame]8191<p>The <tt>llvm.objectsize</tt> intrinsic takes two arguments. The first
Eric Christopher31e39bd2009-12-23 00:29:49 +0000[diff] [blame]8192 argument is a pointer to or into the <tt>object</tt>. The second argument
Bill Wendling6bbe0912010-10-27 01:07:41 +0000[diff] [blame]8193 is a boolean 0 or 1. This argument determines whether you want the
8194 maximum (0) or minimum (1) bytes remaining. This needs to be a literal 0 or
Eric Christopher31e39bd2009-12-23 00:29:49 +0000[diff] [blame]8195 1, variables are not allowed.</p>
8196
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]8197<h5>Semantics:</h5>
8198<p>The <tt>llvm.objectsize</tt> intrinsic is lowered to either a constant
Bill Wendling6bbe0912010-10-27 01:07:41 +0000[diff] [blame]8199 representing the size of the object concerned, or <tt>i32/i64 -1 or 0</tt>,
8200 depending on the <tt>type</tt> argument, if the size cannot be determined at
8201 compile time.</p>
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]8202
8203</div>
8204
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]8205</div>
8206
8207</div>
8208
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]8209<!-- *********************************************************************** -->
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]8210<hr>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]8211<address>
8212 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
Misha Brukman86242e12008-12-11 17:34:48 +0000[diff] [blame]8213 src="http://jigsaw.w3.org/css-validator/images/vcss-blue" alt="Valid CSS"></a>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]8214 <a href="http://validator.w3.org/check/referer"><img
Misha Brukman86242e12008-12-11 17:34:48 +0000[diff] [blame]8215 src="http://www.w3.org/Icons/valid-html401-blue" alt="Valid HTML 4.01"></a>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]8216
8217 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
NAKAMURA Takumica46f5a2011-04-09 02:13:37 +0000[diff] [blame]8218 <a href="http://llvm.org/">The LLVM Compiler Infrastructure</a><br>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]8219 Last modified: $Date$
8220</address>
Chris Lattnerb8f816e2008-01-04 04:33:49 +0000[diff] [blame]8221
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]8222</body>
8223</html>