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gerrit-public.fairphone.software / toolchain / llvm-project / 7bd0ea34875e44b36e9f11ae4e517149db5e287d / . / 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">
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]8 <meta name="description"
Reid Spencercb84e432004-08-26 20:44:00 +0000[diff] [blame]9 content="LLVM Assembly Language Reference Manual.">
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]10 <link rel="stylesheet" href="llvm.css" type="text/css">
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>
Devang Pateld1a89692010-01-11 19:35:55 +0000[diff] [blame]103 <li><a href="#metadata">Metadata Nodes and Metadata Strings</a></li>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]104 </ol>
105 </li>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]106 <li><a href="#intrinsic_globals">Intrinsic Global Variables</a>
107 <ol>
108 <li><a href="#intg_used">The '<tt>llvm.used</tt>' Global Variable</a></li>
Chris Lattner58f9bb22009-07-20 06:14:25 +0000[diff] [blame]109 <li><a href="#intg_compiler_used">The '<tt>llvm.compiler.used</tt>'
110 Global Variable</a></li>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]111 <li><a href="#intg_global_ctors">The '<tt>llvm.global_ctors</tt>'
112 Global Variable</a></li>
113 <li><a href="#intg_global_dtors">The '<tt>llvm.global_dtors</tt>'
114 Global Variable</a></li>
115 </ol>
116 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]117 <li><a href="#instref">Instruction Reference</a>
118 <ol>
119 <li><a href="#terminators">Terminator Instructions</a>
120 <ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]121 <li><a href="#i_ret">'<tt>ret</tt>' Instruction</a></li>
122 <li><a href="#i_br">'<tt>br</tt>' Instruction</a></li>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]123 <li><a href="#i_switch">'<tt>switch</tt>' Instruction</a></li>
Chris Lattnerd04cb6d2009-10-28 00:19:10 +0000[diff] [blame]124 <li><a href="#i_indirectbr">'<tt>indirectbr</tt>' Instruction</a></li>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]125 <li><a href="#i_invoke">'<tt>invoke</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]126 <li><a href="#i_unwind">'<tt>unwind</tt>' Instruction</a></li>
Bill Wendlingf891bf82011-07-31 06:30:59 +0000[diff] [blame]127 <li><a href="#i_resume">'<tt>resume</tt>' Instruction</a></li>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]128 <li><a href="#i_unreachable">'<tt>unreachable</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]129 </ol>
130 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]131 <li><a href="#binaryops">Binary Operations</a>
132 <ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]133 <li><a href="#i_add">'<tt>add</tt>' Instruction</a></li>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]134 <li><a href="#i_fadd">'<tt>fadd</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]135 <li><a href="#i_sub">'<tt>sub</tt>' Instruction</a></li>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]136 <li><a href="#i_fsub">'<tt>fsub</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]137 <li><a href="#i_mul">'<tt>mul</tt>' Instruction</a></li>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]138 <li><a href="#i_fmul">'<tt>fmul</tt>' Instruction</a></li>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]139 <li><a href="#i_udiv">'<tt>udiv</tt>' Instruction</a></li>
140 <li><a href="#i_sdiv">'<tt>sdiv</tt>' Instruction</a></li>
141 <li><a href="#i_fdiv">'<tt>fdiv</tt>' Instruction</a></li>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]142 <li><a href="#i_urem">'<tt>urem</tt>' Instruction</a></li>
143 <li><a href="#i_srem">'<tt>srem</tt>' Instruction</a></li>
144 <li><a href="#i_frem">'<tt>frem</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]145 </ol>
146 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]147 <li><a href="#bitwiseops">Bitwise Binary Operations</a>
148 <ol>
Reid Spencer2ab01932007-02-02 13:57:07 +0000[diff] [blame]149 <li><a href="#i_shl">'<tt>shl</tt>' Instruction</a></li>
150 <li><a href="#i_lshr">'<tt>lshr</tt>' Instruction</a></li>
151 <li><a href="#i_ashr">'<tt>ashr</tt>' Instruction</a></li>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]152 <li><a href="#i_and">'<tt>and</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]153 <li><a href="#i_or">'<tt>or</tt>' Instruction</a></li>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]154 <li><a href="#i_xor">'<tt>xor</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]155 </ol>
156 </li>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]157 <li><a href="#vectorops">Vector Operations</a>
158 <ol>
159 <li><a href="#i_extractelement">'<tt>extractelement</tt>' Instruction</a></li>
160 <li><a href="#i_insertelement">'<tt>insertelement</tt>' Instruction</a></li>
161 <li><a href="#i_shufflevector">'<tt>shufflevector</tt>' Instruction</a></li>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]162 </ol>
163 </li>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]164 <li><a href="#aggregateops">Aggregate Operations</a>
165 <ol>
166 <li><a href="#i_extractvalue">'<tt>extractvalue</tt>' Instruction</a></li>
167 <li><a href="#i_insertvalue">'<tt>insertvalue</tt>' Instruction</a></li>
168 </ol>
169 </li>
Chris Lattner6ab66722006-08-15 00:45:58 +0000[diff] [blame]170 <li><a href="#memoryops">Memory Access and Addressing Operations</a>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]171 <ol>
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]172 <li><a href="#i_alloca">'<tt>alloca</tt>' Instruction</a></li>
173 <li><a href="#i_load">'<tt>load</tt>' Instruction</a></li>
174 <li><a href="#i_store">'<tt>store</tt>' Instruction</a></li>
175 <li><a href="#i_fence">'<tt>fence</tt>' Instruction</a></li>
176 <li><a href="#i_cmpxchg">'<tt>cmpxchg</tt>' Instruction</a></li>
177 <li><a href="#i_atomicrmw">'<tt>atomicrmw</tt>' Instruction</a></li>
Robert Bocchino820bc75b2006-02-17 21:18:08 +0000[diff] [blame]178 <li><a href="#i_getelementptr">'<tt>getelementptr</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]179 </ol>
180 </li>
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]181 <li><a href="#convertops">Conversion Operations</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]182 <ol>
183 <li><a href="#i_trunc">'<tt>trunc .. to</tt>' Instruction</a></li>
184 <li><a href="#i_zext">'<tt>zext .. to</tt>' Instruction</a></li>
185 <li><a href="#i_sext">'<tt>sext .. to</tt>' Instruction</a></li>
186 <li><a href="#i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a></li>
187 <li><a href="#i_fpext">'<tt>fpext .. to</tt>' Instruction</a></li>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]188 <li><a href="#i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a></li>
189 <li><a href="#i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a></li>
190 <li><a href="#i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a></li>
191 <li><a href="#i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a></li>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]192 <li><a href="#i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a></li>
193 <li><a href="#i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a></li>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]194 <li><a href="#i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a></li>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]195 </ol>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]196 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]197 <li><a href="#otherops">Other Operations</a>
198 <ol>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]199 <li><a href="#i_icmp">'<tt>icmp</tt>' Instruction</a></li>
200 <li><a href="#i_fcmp">'<tt>fcmp</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]201 <li><a href="#i_phi">'<tt>phi</tt>' Instruction</a></li>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]202 <li><a href="#i_select">'<tt>select</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]203 <li><a href="#i_call">'<tt>call</tt>' Instruction</a></li>
Chris Lattner33337472006-01-13 23:26:01 +0000[diff] [blame]204 <li><a href="#i_va_arg">'<tt>va_arg</tt>' Instruction</a></li>
Bill Wendlingbbcb7cd2011-08-02 21:52:38 +0000[diff] [blame]205 <li><a href="#i_landingpad">'<tt>landingpad</tt>' Instruction</a></li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]206 </ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]207 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]208 </ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]209 </li>
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]210 <li><a href="#intrinsics">Intrinsic Functions</a>
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]211 <ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]212 <li><a href="#int_varargs">Variable Argument Handling Intrinsics</a>
213 <ol>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]214 <li><a href="#int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a></li>
215 <li><a href="#int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a></li>
216 <li><a href="#int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]217 </ol>
218 </li>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]219 <li><a href="#int_gc">Accurate Garbage Collection Intrinsics</a>
220 <ol>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]221 <li><a href="#int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a></li>
222 <li><a href="#int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a></li>
223 <li><a href="#int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a></li>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]224 </ol>
225 </li>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]226 <li><a href="#int_codegen">Code Generator Intrinsics</a>
227 <ol>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]228 <li><a href="#int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a></li>
229 <li><a href="#int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a></li>
230 <li><a href="#int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a></li>
231 <li><a href="#int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a></li>
232 <li><a href="#int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a></li>
233 <li><a href="#int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a></li>
Dan Gohmane58f7b32010-05-26 21:56:15 +0000[diff] [blame]234 <li><a href="#int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a></li>
John Criswellaa1c3c12004-04-09 16:43:20 +0000[diff] [blame]235 </ol>
236 </li>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]237 <li><a href="#int_libc">Standard C Library Intrinsics</a>
238 <ol>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]239 <li><a href="#int_memcpy">'<tt>llvm.memcpy.*</tt>' Intrinsic</a></li>
240 <li><a href="#int_memmove">'<tt>llvm.memmove.*</tt>' Intrinsic</a></li>
241 <li><a href="#int_memset">'<tt>llvm.memset.*</tt>' Intrinsic</a></li>
242 <li><a href="#int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a></li>
243 <li><a href="#int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a></li>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]244 <li><a href="#int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a></li>
245 <li><a href="#int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a></li>
246 <li><a href="#int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a></li>
Dan Gohmane635c522011-05-27 00:36:31 +0000[diff] [blame]247 <li><a href="#int_exp">'<tt>llvm.exp.*</tt>' Intrinsic</a></li>
248 <li><a href="#int_log">'<tt>llvm.log.*</tt>' Intrinsic</a></li>
Cameron Zwarichf03fa182011-07-08 21:39:21 +0000[diff] [blame]249 <li><a href="#int_fma">'<tt>llvm.fma.*</tt>' Intrinsic</a></li>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]250 </ol>
251 </li>
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]252 <li><a href="#int_manip">Bit Manipulation Intrinsics</a>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]253 <ol>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]254 <li><a href="#int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a></li>
Chris Lattnerb748c672006-01-16 22:34:14 +0000[diff] [blame]255 <li><a href="#int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic </a></li>
256 <li><a href="#int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic </a></li>
257 <li><a href="#int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic </a></li>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]258 </ol>
259 </li>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]260 <li><a href="#int_overflow">Arithmetic with Overflow Intrinsics</a>
261 <ol>
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]262 <li><a href="#int_sadd_overflow">'<tt>llvm.sadd.with.overflow.*</tt> Intrinsics</a></li>
263 <li><a href="#int_uadd_overflow">'<tt>llvm.uadd.with.overflow.*</tt> Intrinsics</a></li>
264 <li><a href="#int_ssub_overflow">'<tt>llvm.ssub.with.overflow.*</tt> Intrinsics</a></li>
265 <li><a href="#int_usub_overflow">'<tt>llvm.usub.with.overflow.*</tt> Intrinsics</a></li>
266 <li><a href="#int_smul_overflow">'<tt>llvm.smul.with.overflow.*</tt> Intrinsics</a></li>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]267 <li><a href="#int_umul_overflow">'<tt>llvm.umul.with.overflow.*</tt> Intrinsics</a></li>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]268 </ol>
269 </li>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]270 <li><a href="#int_fp16">Half Precision Floating Point Intrinsics</a>
271 <ol>
Chris Lattnerbbd8bd32010-03-14 23:03:31 +0000[diff] [blame]272 <li><a href="#int_convert_to_fp16">'<tt>llvm.convert.to.fp16</tt>' Intrinsic</a></li>
273 <li><a href="#int_convert_from_fp16">'<tt>llvm.convert.from.fp16</tt>' Intrinsic</a></li>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]274 </ol>
275 </li>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]276 <li><a href="#int_debugger">Debugger intrinsics</a></li>
Jim Laskey2211f492007-03-14 19:31:19 +0000[diff] [blame]277 <li><a href="#int_eh">Exception Handling intrinsics</a></li>
Duncan Sandsa0984362011-09-06 13:37:06 +0000[diff] [blame]278 <li><a href="#int_trampoline">Trampoline Intrinsics</a>
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]279 <ol>
280 <li><a href="#int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a></li>
Duncan Sandsa0984362011-09-06 13:37:06 +0000[diff] [blame]281 <li><a href="#int_at">'<tt>llvm.adjust.trampoline</tt>' Intrinsic</a></li>
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]282 </ol>
283 </li>
Bill Wendlingf85850f2008-11-18 22:10:53 +0000[diff] [blame]284 <li><a href="#int_atomics">Atomic intrinsics</a>
285 <ol>
286 <li><a href="#int_memory_barrier"><tt>llvm.memory_barrier</tt></a></li>
287 <li><a href="#int_atomic_cmp_swap"><tt>llvm.atomic.cmp.swap</tt></a></li>
288 <li><a href="#int_atomic_swap"><tt>llvm.atomic.swap</tt></a></li>
289 <li><a href="#int_atomic_load_add"><tt>llvm.atomic.load.add</tt></a></li>
290 <li><a href="#int_atomic_load_sub"><tt>llvm.atomic.load.sub</tt></a></li>
291 <li><a href="#int_atomic_load_and"><tt>llvm.atomic.load.and</tt></a></li>
292 <li><a href="#int_atomic_load_nand"><tt>llvm.atomic.load.nand</tt></a></li>
293 <li><a href="#int_atomic_load_or"><tt>llvm.atomic.load.or</tt></a></li>
294 <li><a href="#int_atomic_load_xor"><tt>llvm.atomic.load.xor</tt></a></li>
295 <li><a href="#int_atomic_load_max"><tt>llvm.atomic.load.max</tt></a></li>
296 <li><a href="#int_atomic_load_min"><tt>llvm.atomic.load.min</tt></a></li>
297 <li><a href="#int_atomic_load_umax"><tt>llvm.atomic.load.umax</tt></a></li>
298 <li><a href="#int_atomic_load_umin"><tt>llvm.atomic.load.umin</tt></a></li>
299 </ol>
300 </li>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]301 <li><a href="#int_memorymarkers">Memory Use Markers</a>
302 <ol>
303 <li><a href="#int_lifetime_start"><tt>llvm.lifetime.start</tt></a></li>
304 <li><a href="#int_lifetime_end"><tt>llvm.lifetime.end</tt></a></li>
305 <li><a href="#int_invariant_start"><tt>llvm.invariant.start</tt></a></li>
306 <li><a href="#int_invariant_end"><tt>llvm.invariant.end</tt></a></li>
307 </ol>
308 </li>
Reid Spencer5b2cb0f2007-07-20 19:59:11 +0000[diff] [blame]309 <li><a href="#int_general">General intrinsics</a>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]310 <ol>
Reid Spencer5b2cb0f2007-07-20 19:59:11 +0000[diff] [blame]311 <li><a href="#int_var_annotation">
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]312 '<tt>llvm.var.annotation</tt>' Intrinsic</a></li>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]313 <li><a href="#int_annotation">
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]314 '<tt>llvm.annotation.*</tt>' Intrinsic</a></li>
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]315 <li><a href="#int_trap">
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]316 '<tt>llvm.trap</tt>' Intrinsic</a></li>
317 <li><a href="#int_stackprotector">
318 '<tt>llvm.stackprotector</tt>' Intrinsic</a></li>
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]319 <li><a href="#int_objectsize">
320 '<tt>llvm.objectsize</tt>' Intrinsic</a></li>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]321 </ol>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]322 </li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]323 </ol>
324 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]325</ol>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]326
327<div class="doc_author">
328 <p>Written by <a href="mailto:sabre@nondot.org">Chris Lattner</a>
329 and <a href="mailto:vadve@cs.uiuc.edu">Vikram Adve</a></p>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]330</div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]331
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]332<!-- *********************************************************************** -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]333<h2><a name="abstract">Abstract</a></h2>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]334<!-- *********************************************************************** -->
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]335
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]336<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]337
338<p>This document is a reference manual for the LLVM assembly language. LLVM is
339 a Static Single Assignment (SSA) based representation that provides type
340 safety, low-level operations, flexibility, and the capability of representing
341 'all' high-level languages cleanly. It is the common code representation
342 used throughout all phases of the LLVM compilation strategy.</p>
343
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]344</div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]345
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]346<!-- *********************************************************************** -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]347<h2><a name="introduction">Introduction</a></h2>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]348<!-- *********************************************************************** -->
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]349
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]350<div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]351
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]352<p>The LLVM code representation is designed to be used in three different forms:
353 as an in-memory compiler IR, as an on-disk bitcode representation (suitable
354 for fast loading by a Just-In-Time compiler), and as a human readable
355 assembly language representation. This allows LLVM to provide a powerful
356 intermediate representation for efficient compiler transformations and
357 analysis, while providing a natural means to debug and visualize the
358 transformations. The three different forms of LLVM are all equivalent. This
359 document describes the human readable representation and notation.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]360
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]361<p>The LLVM representation aims to be light-weight and low-level while being
362 expressive, typed, and extensible at the same time. It aims to be a
363 "universal IR" of sorts, by being at a low enough level that high-level ideas
364 may be cleanly mapped to it (similar to how microprocessors are "universal
365 IR's", allowing many source languages to be mapped to them). By providing
366 type information, LLVM can be used as the target of optimizations: for
367 example, through pointer analysis, it can be proven that a C automatic
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]368 variable is never accessed outside of the current function, allowing it to
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]369 be promoted to a simple SSA value instead of a memory location.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]370
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]371<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]372<h4>
373 <a name="wellformed">Well-Formedness</a>
374</h4>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]375
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]376<div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]377
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]378<p>It is important to note that this document describes 'well formed' LLVM
379 assembly language. There is a difference between what the parser accepts and
380 what is considered 'well formed'. For example, the following instruction is
381 syntactically okay, but not well formed:</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]382
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]383<pre class="doc_code">
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]384%x = <a href="#i_add">add</a> i32 1, %x
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]385</pre>
386
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]387<p>because the definition of <tt>%x</tt> does not dominate all of its uses. The
388 LLVM infrastructure provides a verification pass that may be used to verify
389 that an LLVM module is well formed. This pass is automatically run by the
390 parser after parsing input assembly and by the optimizer before it outputs
391 bitcode. The violations pointed out by the verifier pass indicate bugs in
392 transformation passes or input to the parser.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]393
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]394</div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]395
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]396</div>
397
Chris Lattner87a3dbe2007-10-03 17:34:29 +0000[diff] [blame]398<!-- Describe the typesetting conventions here. -->
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]399
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]400<!-- *********************************************************************** -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]401<h2><a name="identifiers">Identifiers</a></h2>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]402<!-- *********************************************************************** -->
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]403
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]404<div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]405
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]406<p>LLVM identifiers come in two basic types: global and local. Global
407 identifiers (functions, global variables) begin with the <tt>'@'</tt>
408 character. Local identifiers (register names, types) begin with
409 the <tt>'%'</tt> character. Additionally, there are three different formats
410 for identifiers, for different purposes:</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]411
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]412<ol>
Reid Spencerb23b65f2007-08-07 14:34:28 +0000[diff] [blame]413 <li>Named values are represented as a string of characters with their prefix.
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]414 For example, <tt>%foo</tt>, <tt>@DivisionByZero</tt>,
415 <tt>%a.really.long.identifier</tt>. The actual regular expression used is
416 '<tt>[%@][a-zA-Z$._][a-zA-Z$._0-9]*</tt>'. Identifiers which require
417 other characters in their names can be surrounded with quotes. Special
418 characters may be escaped using <tt>"\xx"</tt> where <tt>xx</tt> is the
419 ASCII code for the character in hexadecimal. In this way, any character
420 can be used in a name value, even quotes themselves.</li>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]421
Reid Spencerb23b65f2007-08-07 14:34:28 +0000[diff] [blame]422 <li>Unnamed values are represented as an unsigned numeric value with their
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]423 prefix. For example, <tt>%12</tt>, <tt>@2</tt>, <tt>%44</tt>.</li>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]424
Reid Spencer8f08d802004-12-09 18:02:53 +0000[diff] [blame]425 <li>Constants, which are described in a <a href="#constants">section about
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]426 constants</a>, below.</li>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]427</ol>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]428
Reid Spencerb23b65f2007-08-07 14:34:28 +0000[diff] [blame]429<p>LLVM requires that values start with a prefix for two reasons: Compilers
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]430 don't need to worry about name clashes with reserved words, and the set of
431 reserved words may be expanded in the future without penalty. Additionally,
432 unnamed identifiers allow a compiler to quickly come up with a temporary
433 variable without having to avoid symbol table conflicts.</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]434
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]435<p>Reserved words in LLVM are very similar to reserved words in other
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]436 languages. There are keywords for different opcodes
437 ('<tt><a href="#i_add">add</a></tt>',
438 '<tt><a href="#i_bitcast">bitcast</a></tt>',
439 '<tt><a href="#i_ret">ret</a></tt>', etc...), for primitive type names
440 ('<tt><a href="#t_void">void</a></tt>',
441 '<tt><a href="#t_primitive">i32</a></tt>', etc...), and others. These
442 reserved words cannot conflict with variable names, because none of them
443 start with a prefix character (<tt>'%'</tt> or <tt>'@'</tt>).</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]444
445<p>Here is an example of LLVM code to multiply the integer variable
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]446 '<tt>%X</tt>' by 8:</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]447
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]448<p>The easy 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">
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]451%result = <a href="#i_mul">mul</a> i32 %X, 8
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]452</pre>
453
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]454<p>After strength reduction:</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]455
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]456<pre class="doc_code">
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]457%result = <a href="#i_shl">shl</a> i32 %X, i8 3
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]458</pre>
459
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]460<p>And the hard way:</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]461
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]462<pre class="doc_code">
Gabor Greifbd0328f2009-10-28 13:05:07 +0000[diff] [blame]463%0 = <a href="#i_add">add</a> i32 %X, %X <i>; yields {i32}:%0</i>
464%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]465%result = <a href="#i_add">add</a> i32 %1, %1
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]466</pre>
467
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]468<p>This last way of multiplying <tt>%X</tt> by 8 illustrates several important
469 lexical features of LLVM:</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]470
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]471<ol>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]472 <li>Comments are delimited with a '<tt>;</tt>' and go until the end of
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]473 line.</li>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]474
475 <li>Unnamed temporaries are created when the result of a computation is not
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]476 assigned to a named value.</li>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]477
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]478 <li>Unnamed temporaries are numbered sequentially</li>
479</ol>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]480
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]481<p>It also shows a convention that we follow in this document. When
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]482 demonstrating instructions, we will follow an instruction with a comment that
483 defines the type and name of value produced. Comments are shown in italic
484 text.</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]485
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]486</div>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]487
488<!-- *********************************************************************** -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]489<h2><a name="highlevel">High Level Structure</a></h2>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]490<!-- *********************************************************************** -->
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]491<div>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]492<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]493<h3>
494 <a name="modulestructure">Module Structure</a>
495</h3>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]496
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]497<div>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]498
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]499<p>LLVM programs are composed of "Module"s, each of which is a translation unit
500 of the input programs. Each module consists of functions, global variables,
501 and symbol table entries. Modules may be combined together with the LLVM
502 linker, which merges function (and global variable) definitions, resolves
503 forward declarations, and merges symbol table entries. Here is an example of
504 the "hello world" module:</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]505
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]506<pre class="doc_code">
Chris Lattner54a7be72010-08-17 17:13:42 +0000[diff] [blame]507<i>; Declare the string constant as a global constant.</i>&nbsp;
Nick Lewyckyfea7ddc2011-01-29 01:09:53 +0000[diff] [blame]508<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]509
Chris Lattner54a7be72010-08-17 17:13:42 +0000[diff] [blame]510<i>; External declaration of the puts function</i>&nbsp;
511<a href="#functionstructure">declare</a> i32 @puts(i8*) <i>; i32 (i8*)* </i>&nbsp;
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]512
513<i>; Definition of main function</i>
Chris Lattner54a7be72010-08-17 17:13:42 +0000[diff] [blame]514define i32 @main() { <i>; i32()* </i>&nbsp;
515 <i>; Convert [13 x i8]* to i8 *...</i>&nbsp;
516 %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]517
Chris Lattner54a7be72010-08-17 17:13:42 +0000[diff] [blame]518 <i>; Call puts function to write out the string to stdout.</i>&nbsp;
519 <a href="#i_call">call</a> i32 @puts(i8* %cast210) <i>; i32</i>&nbsp;
520 <a href="#i_ret">ret</a> i32 0&nbsp;
521}
Devang Pateld1a89692010-01-11 19:35:55 +0000[diff] [blame]522
523<i>; Named metadata</i>
524!1 = metadata !{i32 41}
525!foo = !{!1, null}
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]526</pre>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]527
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]528<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]529 "<tt>.LC0</tt>", an external declaration of the "<tt>puts</tt>" function,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]530 a <a href="#functionstructure">function definition</a> for
Devang Pateld1a89692010-01-11 19:35:55 +0000[diff] [blame]531 "<tt>main</tt>" and <a href="#namedmetadatastructure">named metadata</a>
532 "<tt>foo"</tt>.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]533
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]534<p>In general, a module is made up of a list of global values, where both
535 functions and global variables are global values. Global values are
536 represented by a pointer to a memory location (in this case, a pointer to an
537 array of char, and a pointer to a function), and have one of the
538 following <a href="#linkage">linkage types</a>.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]539
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]540</div>
541
542<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]543<h3>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]544 <a name="linkage">Linkage Types</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]545</h3>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]546
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]547<div>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]548
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]549<p>All Global Variables and Functions have one of the following types of
550 linkage:</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]551
552<dl>
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]553 <dt><tt><b><a name="linkage_private">private</a></b></tt></dt>
Bill Wendling03bcd6e2010-07-01 21:55:59 +0000[diff] [blame]554 <dd>Global values with "<tt>private</tt>" linkage are only directly accessible
555 by objects in the current module. In particular, linking code into a
556 module with an private global value may cause the private to be renamed as
557 necessary to avoid collisions. Because the symbol is private to the
558 module, all references can be updated. This doesn't show up in any symbol
559 table in the object file.</dd>
Rafael Espindola6de96a12009-01-15 20:18:42 +0000[diff] [blame]560
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]561 <dt><tt><b><a name="linkage_linker_private">linker_private</a></b></tt></dt>
Bill Wendling03bcd6e2010-07-01 21:55:59 +0000[diff] [blame]562 <dd>Similar to <tt>private</tt>, but the symbol is passed through the
563 assembler and evaluated by the linker. Unlike normal strong symbols, they
564 are removed by the linker from the final linked image (executable or
565 dynamic library).</dd>
566
567 <dt><tt><b><a name="linkage_linker_private_weak">linker_private_weak</a></b></tt></dt>
568 <dd>Similar to "<tt>linker_private</tt>", but the symbol is weak. Note that
569 <tt>linker_private_weak</tt> symbols are subject to coalescing by the
570 linker. The symbols are removed by the linker from the final linked image
571 (executable or dynamic library).</dd>
Bill Wendlinga3c6f6b2009-07-20 01:03:30 +0000[diff] [blame]572
Bill Wendling578ee402010-08-20 22:05:50 +0000[diff] [blame]573 <dt><tt><b><a name="linkage_linker_private_weak_def_auto">linker_private_weak_def_auto</a></b></tt></dt>
574 <dd>Similar to "<tt>linker_private_weak</tt>", but it's known that the address
575 of the object is not taken. For instance, functions that had an inline
576 definition, but the compiler decided not to inline it. Note,
577 unlike <tt>linker_private</tt> and <tt>linker_private_weak</tt>,
578 <tt>linker_private_weak_def_auto</tt> may have only <tt>default</tt>
579 visibility. The symbols are removed by the linker from the final linked
580 image (executable or dynamic library).</dd>
581
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]582 <dt><tt><b><a name="linkage_internal">internal</a></b></tt></dt>
Bill Wendling36321712010-06-29 22:34:52 +0000[diff] [blame]583 <dd>Similar to private, but the value shows as a local symbol
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]584 (<tt>STB_LOCAL</tt> in the case of ELF) in the object file. This
585 corresponds to the notion of the '<tt>static</tt>' keyword in C.</dd>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]586
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]587 <dt><tt><b><a name="linkage_available_externally">available_externally</a></b></tt></dt>
Chris Lattner184f1be2009-04-13 05:44:34 +0000[diff] [blame]588 <dd>Globals with "<tt>available_externally</tt>" linkage are never emitted
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]589 into the object file corresponding to the LLVM module. They exist to
590 allow inlining and other optimizations to take place given knowledge of
591 the definition of the global, which is known to be somewhere outside the
592 module. Globals with <tt>available_externally</tt> linkage are allowed to
593 be discarded at will, and are otherwise the same as <tt>linkonce_odr</tt>.
594 This linkage type is only allowed on definitions, not declarations.</dd>
Chris Lattner184f1be2009-04-13 05:44:34 +0000[diff] [blame]595
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]596 <dt><tt><b><a name="linkage_linkonce">linkonce</a></b></tt></dt>
Chris Lattnere20b4702007-01-14 06:51:48 +0000[diff] [blame]597 <dd>Globals with "<tt>linkonce</tt>" linkage are merged with other globals of
Chris Lattner0de4caa2010-01-09 19:15:14 +0000[diff] [blame]598 the same name when linkage occurs. This can be used to implement
599 some forms of inline functions, templates, or other code which must be
600 generated in each translation unit that uses it, but where the body may
601 be overridden with a more definitive definition later. Unreferenced
602 <tt>linkonce</tt> globals are allowed to be discarded. Note that
603 <tt>linkonce</tt> linkage does not actually allow the optimizer to
604 inline the body of this function into callers because it doesn't know if
605 this definition of the function is the definitive definition within the
606 program or whether it will be overridden by a stronger definition.
607 To enable inlining and other optimizations, use "<tt>linkonce_odr</tt>"
608 linkage.</dd>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]609
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]610 <dt><tt><b><a name="linkage_weak">weak</a></b></tt></dt>
Chris Lattnerd0554882009-08-05 05:21:07 +0000[diff] [blame]611 <dd>"<tt>weak</tt>" linkage has the same merging semantics as
612 <tt>linkonce</tt> linkage, except that unreferenced globals with
613 <tt>weak</tt> linkage may not be discarded. This is used for globals that
614 are declared "weak" in C source code.</dd>
615
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]616 <dt><tt><b><a name="linkage_common">common</a></b></tt></dt>
Chris Lattnerd0554882009-08-05 05:21:07 +0000[diff] [blame]617 <dd>"<tt>common</tt>" linkage is most similar to "<tt>weak</tt>" linkage, but
618 they are used for tentative definitions in C, such as "<tt>int X;</tt>" at
619 global scope.
620 Symbols with "<tt>common</tt>" linkage are merged in the same way as
621 <tt>weak symbols</tt>, and they may not be deleted if unreferenced.
Chris Lattner0aff0b22009-08-05 05:41:44 +0000[diff] [blame]622 <tt>common</tt> symbols may not have an explicit section,
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]623 must have a zero initializer, and may not be marked '<a
Chris Lattner0aff0b22009-08-05 05:41:44 +0000[diff] [blame]624 href="#globalvars"><tt>constant</tt></a>'. Functions and aliases may not
625 have common linkage.</dd>
Chris Lattnerd0554882009-08-05 05:21:07 +0000[diff] [blame]626
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]627
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]628 <dt><tt><b><a name="linkage_appending">appending</a></b></tt></dt>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]629 <dd>"<tt>appending</tt>" linkage may only be applied to global variables of
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]630 pointer to array type. When two global variables with appending linkage
631 are linked together, the two global arrays are appended together. This is
632 the LLVM, typesafe, equivalent of having the system linker append together
633 "sections" with identical names when .o files are linked.</dd>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]634
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]635 <dt><tt><b><a name="linkage_externweak">extern_weak</a></b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]636 <dd>The semantics of this linkage follow the ELF object file model: the symbol
637 is weak until linked, if not linked, the symbol becomes null instead of
638 being an undefined reference.</dd>
Anton Korobeynikova0554d92007-01-12 19:20:47 +0000[diff] [blame]639
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]640 <dt><tt><b><a name="linkage_linkonce_odr">linkonce_odr</a></b></tt></dt>
641 <dt><tt><b><a name="linkage_weak_odr">weak_odr</a></b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]642 <dd>Some languages allow differing globals to be merged, such as two functions
643 with different semantics. Other languages, such as <tt>C++</tt>, ensure
Bill Wendling03bcd6e2010-07-01 21:55:59 +0000[diff] [blame]644 that only equivalent globals are ever merged (the "one definition rule"
645 &mdash; "ODR"). Such languages can use the <tt>linkonce_odr</tt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]646 and <tt>weak_odr</tt> linkage types to indicate that the global will only
647 be merged with equivalent globals. These linkage types are otherwise the
648 same as their non-<tt>odr</tt> versions.</dd>
Duncan Sands12da8ce2009-03-07 15:45:40 +0000[diff] [blame]649
Bill Wendlingb4d076e2011-10-11 06:41:28 +0000[diff] [blame]650 <dt><tt><b><a name="linkage_external">external</a></b></tt>:</dt>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]651 <dd>If none of the above identifiers are used, the global is externally
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]652 visible, meaning that it participates in linkage and can be used to
653 resolve external symbol references.</dd>
Reid Spencer7972c472007-04-11 23:49:50 +0000[diff] [blame]654</dl>
Anton Korobeynikovd61d39e2006-09-14 18:23:27 +0000[diff] [blame]655
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]656<p>The next two types of linkage are targeted for Microsoft Windows platform
657 only. They are designed to support importing (exporting) symbols from (to)
658 DLLs (Dynamic Link Libraries).</p>
Anton Korobeynikovd61d39e2006-09-14 18:23:27 +0000[diff] [blame]659
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]660<dl>
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]661 <dt><tt><b><a name="linkage_dllimport">dllimport</a></b></tt></dt>
Anton Korobeynikovd61d39e2006-09-14 18:23:27 +0000[diff] [blame]662 <dd>"<tt>dllimport</tt>" linkage causes the compiler to reference a function
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]663 or variable via a global pointer to a pointer that is set up by the DLL
664 exporting the symbol. On Microsoft Windows targets, the pointer name is
665 formed by combining <code>__imp_</code> and the function or variable
666 name.</dd>
Anton Korobeynikovd61d39e2006-09-14 18:23:27 +0000[diff] [blame]667
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]668 <dt><tt><b><a name="linkage_dllexport">dllexport</a></b></tt></dt>
Anton Korobeynikovd61d39e2006-09-14 18:23:27 +0000[diff] [blame]669 <dd>"<tt>dllexport</tt>" linkage causes the compiler to provide a global
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]670 pointer to a pointer in a DLL, so that it can be referenced with the
671 <tt>dllimport</tt> attribute. On Microsoft Windows targets, the pointer
672 name is formed by combining <code>__imp_</code> and the function or
673 variable name.</dd>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]674</dl>
675
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]676<p>For example, since the "<tt>.LC0</tt>" variable is defined to be internal, if
677 another module defined a "<tt>.LC0</tt>" variable and was linked with this
678 one, one of the two would be renamed, preventing a collision. Since
679 "<tt>main</tt>" and "<tt>puts</tt>" are external (i.e., lacking any linkage
680 declarations), they are accessible outside of the current module.</p>
681
682<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]683 other than <tt>external</tt>, <tt>dllimport</tt>
684 or <tt>extern_weak</tt>.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]685
Duncan Sands12da8ce2009-03-07 15:45:40 +0000[diff] [blame]686<p>Aliases can have only <tt>external</tt>, <tt>internal</tt>, <tt>weak</tt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]687 or <tt>weak_odr</tt> linkages.</p>
688
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]689</div>
690
691<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]692<h3>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]693 <a name="callingconv">Calling Conventions</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]694</h3>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]695
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]696<div>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]697
698<p>LLVM <a href="#functionstructure">functions</a>, <a href="#i_call">calls</a>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]699 and <a href="#i_invoke">invokes</a> can all have an optional calling
700 convention specified for the call. The calling convention of any pair of
701 dynamic caller/callee must match, or the behavior of the program is
702 undefined. The following calling conventions are supported by LLVM, and more
703 may be added in the future:</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]704
705<dl>
706 <dt><b>"<tt>ccc</tt>" - The C calling convention</b>:</dt>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]707 <dd>This calling convention (the default if no other calling convention is
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]708 specified) matches the target C calling conventions. This calling
709 convention supports varargs function calls and tolerates some mismatch in
710 the declared prototype and implemented declaration of the function (as
711 does normal C).</dd>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]712
713 <dt><b>"<tt>fastcc</tt>" - The fast calling convention</b>:</dt>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]714 <dd>This calling convention attempts to make calls as fast as possible
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]715 (e.g. by passing things in registers). This calling convention allows the
716 target to use whatever tricks it wants to produce fast code for the
717 target, without having to conform to an externally specified ABI
Jeffrey Yasskinb8677462010-01-09 19:44:16 +0000[diff] [blame]718 (Application Binary Interface).
719 <a href="CodeGenerator.html#tailcallopt">Tail calls can only be optimized
Chris Lattnera179e4d2010-03-11 00:22:57 +0000[diff] [blame]720 when this or the GHC convention is used.</a> This calling convention
721 does not support varargs and requires the prototype of all callees to
722 exactly match the prototype of the function definition.</dd>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]723
724 <dt><b>"<tt>coldcc</tt>" - The cold calling convention</b>:</dt>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]725 <dd>This calling convention attempts to make code in the caller as efficient
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]726 as possible under the assumption that the call is not commonly executed.
727 As such, these calls often preserve all registers so that the call does
728 not break any live ranges in the caller side. This calling convention
729 does not support varargs and requires the prototype of all callees to
730 exactly match the prototype of the function definition.</dd>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]731
Chris Lattnera179e4d2010-03-11 00:22:57 +0000[diff] [blame]732 <dt><b>"<tt>cc <em>10</em></tt>" - GHC convention</b>:</dt>
733 <dd>This calling convention has been implemented specifically for use by the
734 <a href="http://www.haskell.org/ghc">Glasgow Haskell Compiler (GHC)</a>.
735 It passes everything in registers, going to extremes to achieve this by
736 disabling callee save registers. This calling convention should not be
737 used lightly but only for specific situations such as an alternative to
738 the <em>register pinning</em> performance technique often used when
739 implementing functional programming languages.At the moment only X86
740 supports this convention and it has the following limitations:
741 <ul>
742 <li>On <em>X86-32</em> only supports up to 4 bit type parameters. No
743 floating point types are supported.</li>
744 <li>On <em>X86-64</em> only supports up to 10 bit type parameters and
745 6 floating point parameters.</li>
746 </ul>
747 This calling convention supports
748 <a href="CodeGenerator.html#tailcallopt">tail call optimization</a> but
749 requires both the caller and callee are using it.
750 </dd>
751
Chris Lattner573f64e2005-05-07 01:46:40 +0000[diff] [blame]752 <dt><b>"<tt>cc &lt;<em>n</em>&gt;</tt>" - Numbered convention</b>:</dt>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]753 <dd>Any calling convention may be specified by number, allowing
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]754 target-specific calling conventions to be used. Target specific calling
755 conventions start at 64.</dd>
Chris Lattner573f64e2005-05-07 01:46:40 +0000[diff] [blame]756</dl>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]757
758<p>More calling conventions can be added/defined on an as-needed basis, to
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]759 support Pascal conventions or any other well-known target-independent
760 convention.</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]761
762</div>
763
764<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]765<h3>
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]766 <a name="visibility">Visibility Styles</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]767</h3>
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]768
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]769<div>
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]770
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]771<p>All Global Variables and Functions have one of the following visibility
772 styles:</p>
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]773
774<dl>
775 <dt><b>"<tt>default</tt>" - Default style</b>:</dt>
Chris Lattner67c37d12008-08-05 18:29:16 +0000[diff] [blame]776 <dd>On targets that use the ELF object file format, default visibility means
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]777 that the declaration is visible to other modules and, in shared libraries,
778 means that the declared entity may be overridden. On Darwin, default
779 visibility means that the declaration is visible to other modules. Default
780 visibility corresponds to "external linkage" in the language.</dd>
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]781
782 <dt><b>"<tt>hidden</tt>" - Hidden style</b>:</dt>
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]783 <dd>Two declarations of an object with hidden visibility refer to the same
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]784 object if they are in the same shared object. Usually, hidden visibility
785 indicates that the symbol will not be placed into the dynamic symbol
786 table, so no other module (executable or shared library) can reference it
787 directly.</dd>
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]788
Anton Korobeynikov39f3cff2007-04-29 18:35:00 +0000[diff] [blame]789 <dt><b>"<tt>protected</tt>" - Protected style</b>:</dt>
Anton Korobeynikov39f3cff2007-04-29 18:35:00 +0000[diff] [blame]790 <dd>On ELF, protected visibility indicates that the symbol will be placed in
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]791 the dynamic symbol table, but that references within the defining module
792 will bind to the local symbol. That is, the symbol cannot be overridden by
793 another module.</dd>
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]794</dl>
795
796</div>
797
798<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]799<h3>
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]800 <a name="namedtypes">Named Types</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]801</h3>
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]802
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]803<div>
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]804
805<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]806 it easier to read the IR and make the IR more condensed (particularly when
807 recursive types are involved). An example of a name specification is:</p>
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]808
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]809<pre class="doc_code">
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]810%mytype = type { %mytype*, i32 }
811</pre>
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]812
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]813<p>You may give a name to any <a href="#typesystem">type</a> except
Chris Lattner249b9762010-08-17 23:26:04 +0000[diff] [blame]814 "<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]815 is expected with the syntax "%mytype".</p>
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]816
817<p>Note that type names are aliases for the structural type that they indicate,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]818 and that you can therefore specify multiple names for the same type. This
819 often leads to confusing behavior when dumping out a .ll file. Since LLVM IR
820 uses structural typing, the name is not part of the type. When printing out
821 LLVM IR, the printer will pick <em>one name</em> to render all types of a
822 particular shape. This means that if you have code where two different
823 source types end up having the same LLVM type, that the dumper will sometimes
824 print the "wrong" or unexpected type. This is an important design point and
825 isn't going to change.</p>
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]826
827</div>
828
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]829<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]830<h3>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]831 <a name="globalvars">Global Variables</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]832</h3>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]833
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]834<div>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]835
Chris Lattner5d5aede2005-02-12 19:30:21 +0000[diff] [blame]836<p>Global variables define regions of memory allocated at compilation time
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]837 instead of run-time. Global variables may optionally be initialized, may
838 have an explicit section to be placed in, and may have an optional explicit
839 alignment specified. A variable may be defined as "thread_local", which
840 means that it will not be shared by threads (each thread will have a
841 separated copy of the variable). A variable may be defined as a global
842 "constant," which indicates that the contents of the variable
843 will <b>never</b> be modified (enabling better optimization, allowing the
844 global data to be placed in the read-only section of an executable, etc).
845 Note that variables that need runtime initialization cannot be marked
846 "constant" as there is a store to the variable.</p>
Chris Lattner5d5aede2005-02-12 19:30:21 +0000[diff] [blame]847
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]848<p>LLVM explicitly allows <em>declarations</em> of global variables to be marked
849 constant, even if the final definition of the global is not. This capability
850 can be used to enable slightly better optimization of the program, but
851 requires the language definition to guarantee that optimizations based on the
852 'constantness' are valid for the translation units that do not include the
853 definition.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]854
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]855<p>As SSA values, global variables define pointer values that are in scope
856 (i.e. they dominate) all basic blocks in the program. Global variables
857 always define a pointer to their "content" type because they describe a
858 region of memory, and all memory objects in LLVM are accessed through
859 pointers.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]860
Rafael Espindola45e6c192011-01-08 16:42:36 +0000[diff] [blame]861<p>Global variables can be marked with <tt>unnamed_addr</tt> which indicates
862 that the address is not significant, only the content. Constants marked
Rafael Espindolaf1ed7812011-01-15 08:20:57 +0000[diff] [blame]863 like this can be merged with other constants if they have the same
864 initializer. Note that a constant with significant address <em>can</em>
865 be merged with a <tt>unnamed_addr</tt> constant, the result being a
866 constant whose address is significant.</p>
Rafael Espindola45e6c192011-01-08 16:42:36 +0000[diff] [blame]867
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]868<p>A global variable may be declared to reside in a target-specific numbered
869 address space. For targets that support them, address spaces may affect how
870 optimizations are performed and/or what target instructions are used to
871 access the variable. The default address space is zero. The address space
872 qualifier must precede any other attributes.</p>
Christopher Lamb308121c2007-12-11 09:31:00 +0000[diff] [blame]873
Chris Lattner662c8722005-11-12 00:45:07 +0000[diff] [blame]874<p>LLVM allows an explicit section to be specified for globals. If the target
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]875 supports it, it will emit globals to the section specified.</p>
Chris Lattner662c8722005-11-12 00:45:07 +0000[diff] [blame]876
Chris Lattner78e00bc2010-04-28 00:13:42 +0000[diff] [blame]877<p>An explicit alignment may be specified for a global, which must be a power
878 of 2. If not present, or if the alignment is set to zero, the alignment of
879 the global is set by the target to whatever it feels convenient. If an
880 explicit alignment is specified, the global is forced to have exactly that
Chris Lattner4bd85e42010-04-28 00:31:12 +0000[diff] [blame]881 alignment. Targets and optimizers are not allowed to over-align the global
882 if the global has an assigned section. In this case, the extra alignment
883 could be observable: for example, code could assume that the globals are
884 densely packed in their section and try to iterate over them as an array,
885 alignment padding would break this iteration.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]886
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]887<p>For example, the following defines a global in a numbered address space with
888 an initializer, section, and alignment:</p>
Chris Lattner5760c502007-01-14 00:27:09 +0000[diff] [blame]889
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]890<pre class="doc_code">
Dan Gohmanaaa679b2009-01-11 00:40:00 +0000[diff] [blame]891@G = addrspace(5) constant float 1.0, section "foo", align 4
Chris Lattner5760c502007-01-14 00:27:09 +0000[diff] [blame]892</pre>
893
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]894</div>
895
896
897<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]898<h3>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]899 <a name="functionstructure">Functions</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]900</h3>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]901
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]902<div>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]903
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]904<p>LLVM function definitions consist of the "<tt>define</tt>" keyword, an
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]905 optional <a href="#linkage">linkage type</a>, an optional
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) argument list (each with optional
911 <a href="#paramattrs">parameter attributes</a>), optional
912 <a href="#fnattrs">function attributes</a>, an optional section, an optional
913 alignment, an optional <a href="#gc">garbage collector name</a>, an opening
914 curly brace, a list of basic blocks, and a closing curly brace.</p>
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]915
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]916<p>LLVM function declarations consist of the "<tt>declare</tt>" keyword, an
917 optional <a href="#linkage">linkage type</a>, an optional
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]918 <a href="#visibility">visibility style</a>, an optional
Rafael Espindola45e6c192011-01-08 16:42:36 +0000[diff] [blame]919 <a href="#callingconv">calling convention</a>,
920 an optional <tt>unnamed_addr</tt> attribute, a return type, an optional
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]921 <a href="#paramattrs">parameter attribute</a> for the return type, a function
922 name, a possibly empty list of arguments, an optional alignment, and an
923 optional <a href="#gc">garbage collector name</a>.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]924
Chris Lattner67c37d12008-08-05 18:29:16 +0000[diff] [blame]925<p>A function definition contains a list of basic blocks, forming the CFG
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]926 (Control Flow Graph) for the function. Each basic block may optionally start
927 with a label (giving the basic block a symbol table entry), contains a list
928 of instructions, and ends with a <a href="#terminators">terminator</a>
929 instruction (such as a branch or function return).</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]930
Chris Lattnera59fb102007-06-08 16:52:14 +0000[diff] [blame]931<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]932 executed on entrance to the function, and it is not allowed to have
933 predecessor basic blocks (i.e. there can not be any branches to the entry
934 block of a function). Because the block can have no predecessors, it also
935 cannot have any <a href="#i_phi">PHI nodes</a>.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]936
Chris Lattner662c8722005-11-12 00:45:07 +0000[diff] [blame]937<p>LLVM allows an explicit section to be specified for functions. If the target
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]938 supports it, it will emit functions to the section specified.</p>
Chris Lattner662c8722005-11-12 00:45:07 +0000[diff] [blame]939
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]940<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]941 the alignment is set to zero, the alignment of the function is set by the
942 target to whatever it feels convenient. If an explicit alignment is
943 specified, the function is forced to have at least that much alignment. All
944 alignments must be a power of 2.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]945
Rafael Espindola45e6c192011-01-08 16:42:36 +0000[diff] [blame]946<p>If the <tt>unnamed_addr</tt> attribute is given, the address is know to not
947 be significant and two identical functions can be merged</p>.
948
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]949<h5>Syntax:</h5>
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]950<pre class="doc_code">
Chris Lattner0ae02092008-10-13 16:55:18 +0000[diff] [blame]951define [<a href="#linkage">linkage</a>] [<a href="#visibility">visibility</a>]
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]952 [<a href="#callingconv">cconv</a>] [<a href="#paramattrs">ret attrs</a>]
953 &lt;ResultType&gt; @&lt;FunctionName&gt; ([argument list])
954 [<a href="#fnattrs">fn Attrs</a>] [section "name"] [align N]
955 [<a href="#gc">gc</a>] { ... }
956</pre>
Devang Patel02256232008-10-07 17:48:33 +0000[diff] [blame]957
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]958</div>
959
Anton Korobeynikova97b6942007-04-25 14:27:10 +0000[diff] [blame]960<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]961<h3>
Anton Korobeynikova97b6942007-04-25 14:27:10 +0000[diff] [blame]962 <a name="aliasstructure">Aliases</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]963</h3>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]964
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]965<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]966
967<p>Aliases act as "second name" for the aliasee value (which can be either
968 function, global variable, another alias or bitcast of global value). Aliases
969 may have an optional <a href="#linkage">linkage type</a>, and an
970 optional <a href="#visibility">visibility style</a>.</p>
Anton Korobeynikova97b6942007-04-25 14:27:10 +0000[diff] [blame]971
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]972<h5>Syntax:</h5>
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]973<pre class="doc_code">
Duncan Sands7e99a942008-09-12 20:48:21 +0000[diff] [blame]974@&lt;Name&gt; = alias [Linkage] [Visibility] &lt;AliaseeTy&gt; @&lt;Aliasee&gt;
Bill Wendling2d8b9a82007-05-29 09:42:13 +0000[diff] [blame]975</pre>
Anton Korobeynikova97b6942007-04-25 14:27:10 +0000[diff] [blame]976
977</div>
978
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]979<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]980<h3>
Devang Pateld1a89692010-01-11 19:35:55 +0000[diff] [blame]981 <a name="namedmetadatastructure">Named Metadata</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]982</h3>
Devang Pateld1a89692010-01-11 19:35:55 +0000[diff] [blame]983
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]984<div>
Devang Pateld1a89692010-01-11 19:35:55 +0000[diff] [blame]985
Chris Lattnerc2f8f162010-01-15 21:50:19 +0000[diff] [blame]986<p>Named metadata is a collection of metadata. <a href="#metadata">Metadata
Dan Gohman093cb792010-07-21 18:54:18 +0000[diff] [blame]987 nodes</a> (but not metadata strings) are the only valid operands for
Chris Lattnerc2f8f162010-01-15 21:50:19 +0000[diff] [blame]988 a named metadata.</p>
Devang Pateld1a89692010-01-11 19:35:55 +0000[diff] [blame]989
990<h5>Syntax:</h5>
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]991<pre class="doc_code">
Dan Gohman093cb792010-07-21 18:54:18 +0000[diff] [blame]992; Some unnamed metadata nodes, which are referenced by the named metadata.
993!0 = metadata !{metadata !"zero"}
Devang Pateld1a89692010-01-11 19:35:55 +0000[diff] [blame]994!1 = metadata !{metadata !"one"}
Dan Gohman093cb792010-07-21 18:54:18 +0000[diff] [blame]995!2 = metadata !{metadata !"two"}
Dan Gohman58cd65f2010-07-13 19:48:13 +0000[diff] [blame]996; A named metadata.
Dan Gohman093cb792010-07-21 18:54:18 +0000[diff] [blame]997!name = !{!0, !1, !2}
Devang Pateld1a89692010-01-11 19:35:55 +0000[diff] [blame]998</pre>
Devang Pateld1a89692010-01-11 19:35:55 +0000[diff] [blame]999
1000</div>
1001
1002<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1003<h3>
1004 <a name="paramattrs">Parameter Attributes</a>
1005</h3>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1006
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1007<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1008
1009<p>The return type and each parameter of a function type may have a set of
1010 <i>parameter attributes</i> associated with them. Parameter attributes are
1011 used to communicate additional information about the result or parameters of
1012 a function. Parameter attributes are considered to be part of the function,
1013 not of the function type, so functions with different parameter attributes
1014 can have the same function type.</p>
1015
1016<p>Parameter attributes are simple keywords that follow the type specified. If
1017 multiple parameter attributes are needed, they are space separated. For
1018 example:</p>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]1019
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]1020<pre class="doc_code">
Nick Lewyckydac78d82009-02-15 23:06:14 +0000[diff] [blame]1021declare i32 @printf(i8* noalias nocapture, ...)
Chris Lattnerd2597d72008-10-04 18:33:34 +0000[diff] [blame]1022declare i32 @atoi(i8 zeroext)
1023declare signext i8 @returns_signed_char()
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]1024</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]1025
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1026<p>Note that any attributes for the function result (<tt>nounwind</tt>,
1027 <tt>readonly</tt>) come immediately after the argument list.</p>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1028
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1029<p>Currently, only the following parameter attributes are defined:</p>
Chris Lattner5cee13f2008-01-11 06:20:47 +0000[diff] [blame]1030
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1031<dl>
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1032 <dt><tt><b>zeroext</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1033 <dd>This indicates to the code generator that the parameter or return value
Cameron Zwarichac106272011-03-16 22:20:18 +0000[diff] [blame]1034 should be zero-extended to the extent required by the target's ABI (which
1035 is usually 32-bits, but is 8-bits for a i1 on x86-64) by the caller (for a
1036 parameter) or the callee (for a return value).</dd>
Chris Lattner5cee13f2008-01-11 06:20:47 +0000[diff] [blame]1037
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1038 <dt><tt><b>signext</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1039 <dd>This indicates to the code generator that the parameter or return value
Cameron Zwarich341c36d2011-03-17 14:21:58 +0000[diff] [blame]1040 should be sign-extended to the extent required by the target's ABI (which
1041 is usually 32-bits) by the caller (for a parameter) or the callee (for a
1042 return value).</dd>
Chris Lattner5cee13f2008-01-11 06:20:47 +0000[diff] [blame]1043
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1044 <dt><tt><b>inreg</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1045 <dd>This indicates that this parameter or return value should be treated in a
1046 special target-dependent fashion during while emitting code for a function
1047 call or return (usually, by putting it in a register as opposed to memory,
1048 though some targets use it to distinguish between two different kinds of
1049 registers). Use of this attribute is target-specific.</dd>
Chris Lattner5cee13f2008-01-11 06:20:47 +0000[diff] [blame]1050
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1051 <dt><tt><b><a name="byval">byval</a></b></tt></dt>
Chris Lattnerd78dbee2010-11-20 23:49:06 +0000[diff] [blame]1052 <dd><p>This indicates that the pointer parameter should really be passed by
1053 value to the function. The attribute implies that a hidden copy of the
1054 pointee
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1055 is made between the caller and the callee, so the callee is unable to
1056 modify the value in the callee. This attribute is only valid on LLVM
1057 pointer arguments. It is generally used to pass structs and arrays by
1058 value, but is also valid on pointers to scalars. The copy is considered
1059 to belong to the caller not the callee (for example,
1060 <tt><a href="#readonly">readonly</a></tt> functions should not write to
1061 <tt>byval</tt> parameters). This is not a valid attribute for return
Chris Lattnerd78dbee2010-11-20 23:49:06 +0000[diff] [blame]1062 values.</p>
1063
1064 <p>The byval attribute also supports specifying an alignment with
1065 the align attribute. It indicates the alignment of the stack slot to
1066 form and the known alignment of the pointer specified to the call site. If
1067 the alignment is not specified, then the code generator makes a
1068 target-specific assumption.</p></dd>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1069
Dan Gohman3770af52010-07-02 23:18:08 +0000[diff] [blame]1070 <dt><tt><b><a name="sret">sret</a></b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1071 <dd>This indicates that the pointer parameter specifies the address of a
1072 structure that is the return value of the function in the source program.
1073 This pointer must be guaranteed by the caller to be valid: loads and
1074 stores to the structure may be assumed by the callee to not to trap. This
1075 may only be applied to the first parameter. This is not a valid attribute
1076 for return values. </dd>
1077
Dan Gohman3770af52010-07-02 23:18:08 +0000[diff] [blame]1078 <dt><tt><b><a name="noalias">noalias</a></b></tt></dt>
Dan Gohmandf12d082010-07-02 18:41:32 +0000[diff] [blame]1079 <dd>This indicates that pointer values
1080 <a href="#pointeraliasing"><i>based</i></a> on the argument or return
Dan Gohmande256292010-07-02 23:46:54 +0000[diff] [blame]1081 value do not alias pointer values which are not <i>based</i> on it,
1082 ignoring certain "irrelevant" dependencies.
1083 For a call to the parent function, dependencies between memory
1084 references from before or after the call and from those during the call
1085 are "irrelevant" to the <tt>noalias</tt> keyword for the arguments and
1086 return value used in that call.
Dan Gohmandf12d082010-07-02 18:41:32 +0000[diff] [blame]1087 The caller shares the responsibility with the callee for ensuring that
1088 these requirements are met.
1089 For further details, please see the discussion of the NoAlias response in
Dan Gohman6c858db2010-07-06 15:26:33 +0000[diff] [blame]1090 <a href="AliasAnalysis.html#MustMayNo">alias analysis</a>.<br>
1091<br>
John McCall72ed8902010-07-06 21:07:14 +0000[diff] [blame]1092 Note that this definition of <tt>noalias</tt> is intentionally
1093 similar to the definition of <tt>restrict</tt> in C99 for function
Chris Lattner5eff9ca2010-07-06 20:51:35 +0000[diff] [blame]1094 arguments, though it is slightly weaker.
Dan Gohman6c858db2010-07-06 15:26:33 +0000[diff] [blame]1095<br>
1096 For function return values, C99's <tt>restrict</tt> is not meaningful,
1097 while LLVM's <tt>noalias</tt> is.
1098 </dd>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1099
Dan Gohman3770af52010-07-02 23:18:08 +0000[diff] [blame]1100 <dt><tt><b><a name="nocapture">nocapture</a></b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1101 <dd>This indicates that the callee does not make any copies of the pointer
1102 that outlive the callee itself. This is not a valid attribute for return
1103 values.</dd>
1104
Dan Gohman3770af52010-07-02 23:18:08 +0000[diff] [blame]1105 <dt><tt><b><a name="nest">nest</a></b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1106 <dd>This indicates that the pointer parameter can be excised using the
1107 <a href="#int_trampoline">trampoline intrinsics</a>. This is not a valid
1108 attribute for return values.</dd>
1109</dl>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1110
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1111</div>
1112
1113<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1114<h3>
Gordon Henriksen71183b62007-12-10 03:18:06 +0000[diff] [blame]1115 <a name="gc">Garbage Collector Names</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1116</h3>
Gordon Henriksen71183b62007-12-10 03:18:06 +0000[diff] [blame]1117
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1118<div>
Gordon Henriksen71183b62007-12-10 03:18:06 +0000[diff] [blame]1119
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1120<p>Each function may specify a garbage collector name, which is simply a
1121 string:</p>
1122
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]1123<pre class="doc_code">
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1124define void @f() gc "name" { ... }
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1125</pre>
Gordon Henriksen71183b62007-12-10 03:18:06 +0000[diff] [blame]1126
1127<p>The compiler declares the supported values of <i>name</i>. Specifying a
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1128 collector which will cause the compiler to alter its output in order to
1129 support the named garbage collection algorithm.</p>
1130
Gordon Henriksen71183b62007-12-10 03:18:06 +0000[diff] [blame]1131</div>
1132
1133<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1134<h3>
Devang Patel9eb525d2008-09-26 23:51:19 +0000[diff] [blame]1135 <a name="fnattrs">Function Attributes</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1136</h3>
Devang Patelcaacdba2008-09-04 23:05:13 +0000[diff] [blame]1137
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1138<div>
Devang Patel9eb525d2008-09-26 23:51:19 +0000[diff] [blame]1139
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1140<p>Function attributes are set to communicate additional information about a
1141 function. Function attributes are considered to be part of the function, not
1142 of the function type, so functions with different parameter attributes can
1143 have the same function type.</p>
Devang Patel9eb525d2008-09-26 23:51:19 +0000[diff] [blame]1144
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1145<p>Function attributes are simple keywords that follow the type specified. If
1146 multiple attributes are needed, they are space separated. For example:</p>
Devang Patelcaacdba2008-09-04 23:05:13 +0000[diff] [blame]1147
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]1148<pre class="doc_code">
Devang Patel9eb525d2008-09-26 23:51:19 +0000[diff] [blame]1149define void @f() noinline { ... }
1150define void @f() alwaysinline { ... }
1151define void @f() alwaysinline optsize { ... }
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1152define void @f() optsize { ... }
Bill Wendlingb175fa42008-09-07 10:26:33 +0000[diff] [blame]1153</pre>
Devang Patelcaacdba2008-09-04 23:05:13 +0000[diff] [blame]1154
Bill Wendlingb175fa42008-09-07 10:26:33 +0000[diff] [blame]1155<dl>
Charles Davisbe5557e2010-02-12 00:31:15 +0000[diff] [blame]1156 <dt><tt><b>alignstack(&lt;<em>n</em>&gt;)</b></tt></dt>
1157 <dd>This attribute indicates that, when emitting the prologue and epilogue,
1158 the backend should forcibly align the stack pointer. Specify the
1159 desired alignment, which must be a power of two, in parentheses.
1160
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1161 <dt><tt><b>alwaysinline</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1162 <dd>This attribute indicates that the inliner should attempt to inline this
1163 function into callers whenever possible, ignoring any active inlining size
1164 threshold for this caller.</dd>
Bill Wendlingb175fa42008-09-07 10:26:33 +0000[diff] [blame]1165
Dan Gohman8bd11f12011-06-16 16:03:13 +0000[diff] [blame]1166 <dt><tt><b>nonlazybind</b></tt></dt>
1167 <dd>This attribute suppresses lazy symbol binding for the function. This
1168 may make calls to the function faster, at the cost of extra program
1169 startup time if the function is not called during program startup.</dd>
1170
Jakob Stoklund Olesen74bb06c2010-02-06 01:16:28 +0000[diff] [blame]1171 <dt><tt><b>inlinehint</b></tt></dt>
1172 <dd>This attribute indicates that the source code contained a hint that inlining
1173 this function is desirable (such as the "inline" keyword in C/C++). It
1174 is just a hint; it imposes no requirements on the inliner.</dd>
1175
Nick Lewycky14b58da2010-07-06 18:24:09 +0000[diff] [blame]1176 <dt><tt><b>naked</b></tt></dt>
1177 <dd>This attribute disables prologue / epilogue emission for the function.
1178 This can have very system-specific consequences.</dd>
1179
1180 <dt><tt><b>noimplicitfloat</b></tt></dt>
1181 <dd>This attributes disables implicit floating point instructions.</dd>
1182
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1183 <dt><tt><b>noinline</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1184 <dd>This attribute indicates that the inliner should never inline this
1185 function in any situation. This attribute may not be used together with
1186 the <tt>alwaysinline</tt> attribute.</dd>
Devang Patel9eb525d2008-09-26 23:51:19 +0000[diff] [blame]1187
Nick Lewycky14b58da2010-07-06 18:24:09 +0000[diff] [blame]1188 <dt><tt><b>noredzone</b></tt></dt>
1189 <dd>This attribute indicates that the code generator should not use a red
1190 zone, even if the target-specific ABI normally permits it.</dd>
Devang Patel9eb525d2008-09-26 23:51:19 +0000[diff] [blame]1191
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1192 <dt><tt><b>noreturn</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1193 <dd>This function attribute indicates that the function never returns
1194 normally. This produces undefined behavior at runtime if the function
1195 ever does dynamically return.</dd>
Bill Wendlinga8130172008-11-13 01:02:51 +0000[diff] [blame]1196
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1197 <dt><tt><b>nounwind</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1198 <dd>This function attribute indicates that the function never returns with an
1199 unwind or exceptional control flow. If the function does unwind, its
1200 runtime behavior is undefined.</dd>
Bill Wendling0f5541e2008-11-26 19:07:40 +0000[diff] [blame]1201
Nick Lewycky14b58da2010-07-06 18:24:09 +0000[diff] [blame]1202 <dt><tt><b>optsize</b></tt></dt>
1203 <dd>This attribute suggests that optimization passes and code generator passes
1204 make choices that keep the code size of this function low, and otherwise
1205 do optimizations specifically to reduce code size.</dd>
1206
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1207 <dt><tt><b>readnone</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1208 <dd>This attribute indicates that the function computes its result (or decides
1209 to unwind an exception) based strictly on its arguments, without
1210 dereferencing any pointer arguments or otherwise accessing any mutable
1211 state (e.g. memory, control registers, etc) visible to caller functions.
1212 It does not write through any pointer arguments
1213 (including <tt><a href="#byval">byval</a></tt> arguments) and never
1214 changes any state visible to callers. This means that it cannot unwind
1215 exceptions by calling the <tt>C++</tt> exception throwing methods, but
1216 could use the <tt>unwind</tt> instruction.</dd>
Devang Patel310fd4a2009-06-12 19:45:19 +0000[diff] [blame]1217
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1218 <dt><tt><b><a name="readonly">readonly</a></b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1219 <dd>This attribute indicates that the function does not write through any
1220 pointer arguments (including <tt><a href="#byval">byval</a></tt>
1221 arguments) or otherwise modify any state (e.g. memory, control registers,
1222 etc) visible to caller functions. It may dereference pointer arguments
1223 and read state that may be set in the caller. A readonly function always
1224 returns the same value (or unwinds an exception identically) when called
1225 with the same set of arguments and global state. It cannot unwind an
1226 exception by calling the <tt>C++</tt> exception throwing methods, but may
1227 use the <tt>unwind</tt> instruction.</dd>
Anton Korobeynikovc8ce7b082009-07-17 18:07:26 +0000[diff] [blame]1228
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1229 <dt><tt><b><a name="ssp">ssp</a></b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1230 <dd>This attribute indicates that the function should emit a stack smashing
1231 protector. It is in the form of a "canary"&mdash;a random value placed on
1232 the stack before the local variables that's checked upon return from the
1233 function to see if it has been overwritten. A heuristic is used to
1234 determine if a function needs stack protectors or not.<br>
1235<br>
1236 If a function that has an <tt>ssp</tt> attribute is inlined into a
1237 function that doesn't have an <tt>ssp</tt> attribute, then the resulting
1238 function will have an <tt>ssp</tt> attribute.</dd>
1239
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1240 <dt><tt><b>sspreq</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1241 <dd>This attribute indicates that the function should <em>always</em> emit a
1242 stack smashing protector. This overrides
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1243 the <tt><a href="#ssp">ssp</a></tt> function attribute.<br>
1244<br>
1245 If a function that has an <tt>sspreq</tt> attribute is inlined into a
1246 function that doesn't have an <tt>sspreq</tt> attribute or which has
1247 an <tt>ssp</tt> attribute, then the resulting function will have
1248 an <tt>sspreq</tt> attribute.</dd>
Rafael Espindola163d6752011-07-25 15:27:59 +0000[diff] [blame]1249
1250 <dt><tt><b><a name="uwtable">uwtable</a></b></tt></dt>
1251 <dd>This attribute indicates that the ABI being targeted requires that
1252 an unwind table entry be produce for this function even if we can
1253 show that no exceptions passes by it. This is normally the case for
1254 the ELF x86-64 abi, but it can be disabled for some compilation
1255 units.</dd>
1256
Rafael Espindolacc349c82011-10-03 14:45:37 +0000[diff] [blame]1257 <dt><tt><b><a name="returns_twice">returns_twice</a></b></tt></dt>
1258 <dd>This attribute indicates that this function can return
1259 twice. The C <code>setjmp</code> is an example of such a function.
1260 The compiler disables some optimizations (like tail calls) in the caller of
1261 these functions.</dd>
Bill Wendlingb175fa42008-09-07 10:26:33 +0000[diff] [blame]1262</dl>
1263
Devang Patelcaacdba2008-09-04 23:05:13 +0000[diff] [blame]1264</div>
1265
1266<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1267<h3>
Chris Lattner93564892006-04-08 04:40:53 +0000[diff] [blame]1268 <a name="moduleasm">Module-Level Inline Assembly</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1269</h3>
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]1270
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1271<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1272
1273<p>Modules may contain "module-level inline asm" blocks, which corresponds to
1274 the GCC "file scope inline asm" blocks. These blocks are internally
1275 concatenated by LLVM and treated as a single unit, but may be separated in
1276 the <tt>.ll</tt> file if desired. The syntax is very simple:</p>
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]1277
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]1278<pre class="doc_code">
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]1279module asm "inline asm code goes here"
1280module asm "more can go here"
1281</pre>
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]1282
1283<p>The strings can contain any character by escaping non-printable characters.
1284 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]1285 for the number.</p>
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]1286
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1287<p>The inline asm code is simply printed to the machine code .s file when
1288 assembly code is generated.</p>
1289
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]1290</div>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]1291
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1292<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1293<h3>
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1294 <a name="datalayout">Data Layout</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1295</h3>
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1296
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1297<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1298
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1299<p>A module may specify a target specific data layout string that specifies how
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1300 data is to be laid out in memory. The syntax for the data layout is
1301 simply:</p>
1302
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]1303<pre class="doc_code">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1304target datalayout = "<i>layout specification</i>"
1305</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1306
1307<p>The <i>layout specification</i> consists of a list of specifications
1308 separated by the minus sign character ('-'). Each specification starts with
1309 a letter and may include other information after the letter to define some
1310 aspect of the data layout. The specifications accepted are as follows:</p>
1311
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1312<dl>
1313 <dt><tt>E</tt></dt>
1314 <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]1315 bits with the most significance have the lowest address location.</dd>
1316
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1317 <dt><tt>e</tt></dt>
Chris Lattner67c37d12008-08-05 18:29:16 +0000[diff] [blame]1318 <dd>Specifies that the target lays out data in little-endian form. That is,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1319 the bits with the least significance have the lowest address
1320 location.</dd>
1321
Lang Hamesde7ab802011-10-10 23:42:08 +0000[diff] [blame]1322 <dt><tt>S<i>size</i></tt></dt>
1323 <dd>Specifies the natural alignment of the stack in bits. Alignment promotion
1324 of stack variables is limited to the natural stack alignment to avoid
1325 dynamic stack realignment. The stack alignment must be a multiple of
Lang Hamesff2c52c2011-10-11 17:50:14 +0000[diff] [blame]1326 8-bits. If omitted, the natural stack alignment defaults to "unspecified",
1327 which does not prevent any alignment promotions.</dd>
Lang Hamesde7ab802011-10-10 23:42:08 +0000[diff] [blame]1328
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1329 <dt><tt>p:<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]1330 <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]1331 <i>preferred</i> alignments. All sizes are in bits. Specifying
1332 the <i>pref</i> alignment is optional. If omitted, the
1333 preceding <tt>:</tt> should be omitted too.</dd>
1334
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1335 <dt><tt>i<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1336 <dd>This specifies the alignment for an integer type of a given bit
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1337 <i>size</i>. The value of <i>size</i> must be in the range [1,2^23).</dd>
1338
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1339 <dt><tt>v<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]1340 <dd>This specifies the alignment for a vector type of a given bit
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1341 <i>size</i>.</dd>
1342
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1343 <dt><tt>f<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]1344 <dd>This specifies the alignment for a floating point type of a given bit
Dale Johannesence522852010-05-28 18:54:47 +0000[diff] [blame]1345 <i>size</i>. Only values of <i>size</i> that are supported by the target
1346 will work. 32 (float) and 64 (double) are supported on all targets;
1347 80 or 128 (different flavors of long double) are also supported on some
1348 targets.
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1349
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1350 <dt><tt>a<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1351 <dd>This specifies the alignment for an aggregate type of a given bit
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1352 <i>size</i>.</dd>
1353
Daniel Dunbar7921a592009-06-08 22:17:53 +0000[diff] [blame]1354 <dt><tt>s<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1355 <dd>This specifies the alignment for a stack object of a given bit
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1356 <i>size</i>.</dd>
Chris Lattnera381eff2009-11-07 09:35:34 +0000[diff] [blame]1357
1358 <dt><tt>n<i>size1</i>:<i>size2</i>:<i>size3</i>...</tt></dt>
1359 <dd>This specifies a set of native integer widths for the target CPU
1360 in bits. For example, it might contain "n32" for 32-bit PowerPC,
1361 "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]1362 this set are considered to support most general arithmetic
Chris Lattnera381eff2009-11-07 09:35:34 +0000[diff] [blame]1363 operations efficiently.</dd>
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1364</dl>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1365
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1366<p>When constructing the data layout for a given target, LLVM starts with a
Dan Gohman61110ae2010-04-28 00:36:01 +0000[diff] [blame]1367 default set of specifications which are then (possibly) overridden by the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1368 specifications in the <tt>datalayout</tt> keyword. The default specifications
1369 are given in this list:</p>
1370
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1371<ul>
1372 <li><tt>E</tt> - big endian</li>
Dan Gohman8ad777d2010-02-23 02:44:03 +0000[diff] [blame]1373 <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]1374 <li><tt>i1:8:8</tt> - i1 is 8-bit (byte) aligned</li>
1375 <li><tt>i8:8:8</tt> - i8 is 8-bit (byte) aligned</li>
1376 <li><tt>i16:16:16</tt> - i16 is 16-bit aligned</li>
1377 <li><tt>i32:32:32</tt> - i32 is 32-bit aligned</li>
Chris Lattner67c37d12008-08-05 18:29:16 +0000[diff] [blame]1378 <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]1379 alignment of 64-bits</li>
1380 <li><tt>f32:32:32</tt> - float is 32-bit aligned</li>
1381 <li><tt>f64:64:64</tt> - double is 64-bit aligned</li>
1382 <li><tt>v64:64:64</tt> - 64-bit vector is 64-bit aligned</li>
1383 <li><tt>v128:128:128</tt> - 128-bit vector is 128-bit aligned</li>
1384 <li><tt>a0:0:1</tt> - aggregates are 8-bit aligned</li>
Daniel Dunbar7921a592009-06-08 22:17:53 +0000[diff] [blame]1385 <li><tt>s0:64:64</tt> - stack objects are 64-bit aligned</li>
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1386</ul>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1387
1388<p>When LLVM is determining the alignment for a given type, it uses the
1389 following rules:</p>
1390
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1391<ol>
1392 <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]1393 specification is used.</li>
1394
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1395 <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]1396 smallest integer type that is larger than the bitwidth of the sought type
1397 is used. If none of the specifications are larger than the bitwidth then
1398 the the largest integer type is used. For example, given the default
1399 specifications above, the i7 type will use the alignment of i8 (next
1400 largest) while both i65 and i256 will use the alignment of i64 (largest
1401 specified).</li>
1402
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1403 <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]1404 largest vector type that is smaller than the sought vector type will be
1405 used as a fall back. This happens because &lt;128 x double&gt; can be
1406 implemented in terms of 64 &lt;2 x double&gt;, for example.</li>
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1407</ol>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1408
Chris Lattner48797402011-10-11 23:01:39 +0000[diff] [blame]1409<p>The function of the data layout string may not be what you expect. Notably,
1410 this is not a specification from the frontend of what alignment the code
1411 generator should use.</p>
1412
1413<p>Instead, if specified, the target data layout is required to match what the
1414 ultimate <em>code generator</em> expects. This string is used by the
1415 mid-level optimizers to
1416 improve code, and this only works if it matches what the ultimate code
1417 generator uses. If you would like to generate IR that does not embed this
1418 target-specific detail into the IR, then you don't have to specify the
1419 string. This will disable some optimizations that require precise layout
1420 information, but this also prevents those optimizations from introducing
1421 target specificity into the IR.</p>
1422
1423
1424
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1425</div>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]1426
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1427<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1428<h3>
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1429 <a name="pointeraliasing">Pointer Aliasing Rules</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1430</h3>
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1431
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1432<div>
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1433
Andreas Bolka8ae4e242009-07-29 00:02:05 +0000[diff] [blame]1434<p>Any memory access must be done through a pointer value associated
Andreas Bolkae39f0332009-07-27 20:37:10 +0000[diff] [blame]1435with an address range of the memory access, otherwise the behavior
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1436is undefined. Pointer values are associated with address ranges
1437according to the following rules:</p>
1438
1439<ul>
Dan Gohmandf12d082010-07-02 18:41:32 +0000[diff] [blame]1440 <li>A pointer value is associated with the addresses associated with
1441 any value it is <i>based</i> on.
Andreas Bolka8ae4e242009-07-29 00:02:05 +0000[diff] [blame]1442 <li>An address of a global variable is associated with the address
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1443 range of the variable's storage.</li>
1444 <li>The result value of an allocation instruction is associated with
1445 the address range of the allocated storage.</li>
1446 <li>A null pointer in the default address-space is associated with
Andreas Bolka8ae4e242009-07-29 00:02:05 +0000[diff] [blame]1447 no address.</li>
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1448 <li>An integer constant other than zero or a pointer value returned
1449 from a function not defined within LLVM may be associated with address
1450 ranges allocated through mechanisms other than those provided by
Andreas Bolka8ae4e242009-07-29 00:02:05 +0000[diff] [blame]1451 LLVM. Such ranges shall not overlap with any ranges of addresses
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1452 allocated by mechanisms provided by LLVM.</li>
Dan Gohmandf12d082010-07-02 18:41:32 +0000[diff] [blame]1453</ul>
1454
1455<p>A pointer value is <i>based</i> on another pointer value according
1456 to the following rules:</p>
1457
1458<ul>
1459 <li>A pointer value formed from a
1460 <tt><a href="#i_getelementptr">getelementptr</a></tt> operation
1461 is <i>based</i> on the first operand of the <tt>getelementptr</tt>.</li>
1462 <li>The result value of a
1463 <tt><a href="#i_bitcast">bitcast</a></tt> is <i>based</i> on the operand
1464 of the <tt>bitcast</tt>.</li>
1465 <li>A pointer value formed by an
1466 <tt><a href="#i_inttoptr">inttoptr</a></tt> is <i>based</i> on all
1467 pointer values that contribute (directly or indirectly) to the
1468 computation of the pointer's value.</li>
1469 <li>The "<i>based</i> on" relationship is transitive.</li>
1470</ul>
1471
1472<p>Note that this definition of <i>"based"</i> is intentionally
1473 similar to the definition of <i>"based"</i> in C99, though it is
1474 slightly weaker.</p>
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1475
1476<p>LLVM IR does not associate types with memory. The result type of a
Andreas Bolka8ae4e242009-07-29 00:02:05 +0000[diff] [blame]1477<tt><a href="#i_load">load</a></tt> merely indicates the size and
1478alignment of the memory from which to load, as well as the
Dan Gohman4eb47192010-06-17 19:23:50 +0000[diff] [blame]1479interpretation of the value. The first operand type of a
Andreas Bolka8ae4e242009-07-29 00:02:05 +0000[diff] [blame]1480<tt><a href="#i_store">store</a></tt> similarly only indicates the size
1481and alignment of the store.</p>
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1482
1483<p>Consequently, type-based alias analysis, aka TBAA, aka
1484<tt>-fstrict-aliasing</tt>, is not applicable to general unadorned
1485LLVM IR. <a href="#metadata">Metadata</a> may be used to encode
1486additional information which specialized optimization passes may use
1487to implement type-based alias analysis.</p>
1488
1489</div>
1490
Jeffrey Yasskin5d284ae2010-04-26 21:21:24 +0000[diff] [blame]1491<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1492<h3>
Jeffrey Yasskin5d284ae2010-04-26 21:21:24 +0000[diff] [blame]1493 <a name="volatile">Volatile Memory Accesses</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1494</h3>
Jeffrey Yasskin5d284ae2010-04-26 21:21:24 +0000[diff] [blame]1495
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1496<div>
Jeffrey Yasskin5d284ae2010-04-26 21:21:24 +0000[diff] [blame]1497
1498<p>Certain memory accesses, such as <a href="#i_load"><tt>load</tt></a>s, <a
1499href="#i_store"><tt>store</tt></a>s, and <a
1500href="#int_memcpy"><tt>llvm.memcpy</tt></a>s may be marked <tt>volatile</tt>.
1501The optimizers must not change the number of volatile operations or change their
1502order of execution relative to other volatile operations. The optimizers
1503<i>may</i> change the order of volatile operations relative to non-volatile
1504operations. This is not Java's "volatile" and has no cross-thread
1505synchronization behavior.</p>
1506
1507</div>
1508
Eli Friedman35b54aa2011-07-20 21:35:53 +0000[diff] [blame]1509<!-- ======================================================================= -->
1510<h3>
1511 <a name="memmodel">Memory Model for Concurrent Operations</a>
1512</h3>
1513
1514<div>
1515
1516<p>The LLVM IR does not define any way to start parallel threads of execution
1517or to register signal handlers. Nonetheless, there are platform-specific
1518ways to create them, and we define LLVM IR's behavior in their presence. This
1519model is inspired by the C++0x memory model.</p>
1520
Eli Friedman95f69a42011-08-22 21:35:27 +0000[diff] [blame]1521<p>For a more informal introduction to this model, see the
1522<a href="Atomics.html">LLVM Atomic Instructions and Concurrency Guide</a>.
1523
Eli Friedman35b54aa2011-07-20 21:35:53 +0000[diff] [blame]1524<p>We define a <i>happens-before</i> partial order as the least partial order
1525that</p>
1526<ul>
1527 <li>Is a superset of single-thread program order, and</li>
1528 <li>When a <i>synchronizes-with</i> <tt>b</tt>, includes an edge from
1529 <tt>a</tt> to <tt>b</tt>. <i>Synchronizes-with</i> pairs are introduced
1530 by platform-specific techniques, like pthread locks, thread
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]1531 creation, thread joining, etc., and by atomic instructions.
1532 (See also <a href="#ordering">Atomic Memory Ordering Constraints</a>).
1533 </li>
Eli Friedman35b54aa2011-07-20 21:35:53 +0000[diff] [blame]1534</ul>
1535
1536<p>Note that program order does not introduce <i>happens-before</i> edges
1537between a thread and signals executing inside that thread.</p>
1538
1539<p>Every (defined) read operation (load instructions, memcpy, atomic
1540loads/read-modify-writes, etc.) <var>R</var> reads a series of bytes written by
1541(defined) write operations (store instructions, atomic
Eli Friedmanf12e4e92011-07-22 03:04:45 +0000[diff] [blame]1542stores/read-modify-writes, memcpy, etc.). For the purposes of this section,
1543initialized globals are considered to have a write of the initializer which is
1544atomic and happens before any other read or write of the memory in question.
1545For each byte of a read <var>R</var>, <var>R<sub>byte</sub></var> may see
1546any write to the same byte, except:</p>
Eli Friedman35b54aa2011-07-20 21:35:53 +0000[diff] [blame]1547
1548<ul>
1549 <li>If <var>write<sub>1</sub></var> happens before
1550 <var>write<sub>2</sub></var>, and <var>write<sub>2</sub></var> happens
1551 before <var>R<sub>byte</sub></var>, then <var>R<sub>byte</sub></var>
Eli Friedmanf12e4e92011-07-22 03:04:45 +0000[diff] [blame]1552 does not see <var>write<sub>1</sub></var>.
Bill Wendling537603b2011-07-31 06:45:03 +0000[diff] [blame]1553 <li>If <var>R<sub>byte</sub></var> happens before
1554 <var>write<sub>3</sub></var>, then <var>R<sub>byte</sub></var> does not
1555 see <var>write<sub>3</sub></var>.
Eli Friedman35b54aa2011-07-20 21:35:53 +0000[diff] [blame]1556</ul>
1557
1558<p>Given that definition, <var>R<sub>byte</sub></var> is defined as follows:
1559<ul>
Eli Friedman95f69a42011-08-22 21:35:27 +0000[diff] [blame]1560 <li>If <var>R</var> is volatile, the result is target-dependent. (Volatile
1561 is supposed to give guarantees which can support
1562 <code>sig_atomic_t</code> in C/C++, and may be used for accesses to
1563 addresses which do not behave like normal memory. It does not generally
1564 provide cross-thread synchronization.)
1565 <li>Otherwise, if there is no write to the same byte that happens before
Eli Friedman35b54aa2011-07-20 21:35:53 +0000[diff] [blame]1566 <var>R<sub>byte</sub></var>, <var>R<sub>byte</sub></var> returns
1567 <tt>undef</tt> for that byte.
Eli Friedmanf12e4e92011-07-22 03:04:45 +0000[diff] [blame]1568 <li>Otherwise, if <var>R<sub>byte</sub></var> may see exactly one write,
Eli Friedman35b54aa2011-07-20 21:35:53 +0000[diff] [blame]1569 <var>R<sub>byte</sub></var> returns the value written by that
1570 write.</li>
Eli Friedmanf12e4e92011-07-22 03:04:45 +0000[diff] [blame]1571 <li>Otherwise, if <var>R</var> is atomic, and all the writes
1572 <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]1573 values written. See the <a href="#ordering">Atomic Memory Ordering
1574 Constraints</a> section for additional constraints on how the choice
1575 is made.
Eli Friedman35b54aa2011-07-20 21:35:53 +0000[diff] [blame]1576 <li>Otherwise <var>R<sub>byte</sub></var> returns <tt>undef</tt>.</li>
1577</ul>
1578
1579<p><var>R</var> returns the value composed of the series of bytes it read.
1580This implies that some bytes within the value may be <tt>undef</tt>
1581<b>without</b> the entire value being <tt>undef</tt>. Note that this only
1582defines the semantics of the operation; it doesn't mean that targets will
1583emit more than one instruction to read the series of bytes.</p>
1584
1585<p>Note that in cases where none of the atomic intrinsics are used, this model
1586places only one restriction on IR transformations on top of what is required
1587for single-threaded execution: introducing a store to a byte which might not
Eli Friedman4bc9f3c2011-08-02 01:15:34 +0000[diff] [blame]1588otherwise be stored is not allowed in general. (Specifically, in the case
1589where another thread might write to and read from an address, introducing a
1590store can change a load that may see exactly one write into a load that may
1591see multiple writes.)</p>
Eli Friedman35b54aa2011-07-20 21:35:53 +0000[diff] [blame]1592
1593<!-- FIXME: This model assumes all targets where concurrency is relevant have
1594a byte-size store which doesn't affect adjacent bytes. As far as I can tell,
1595none of the backends currently in the tree fall into this category; however,
1596there might be targets which care. If there are, we want a paragraph
1597like the following:
1598
1599Targets may specify that stores narrower than a certain width are not
1600available; on such a target, for the purposes of this model, treat any
1601non-atomic write with an alignment or width less than the minimum width
1602as if it writes to the relevant surrounding bytes.
1603-->
1604
1605</div>
1606
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]1607<!-- ======================================================================= -->
NAKAMURA Takumi0300d882011-08-12 06:17:17 +0000[diff] [blame]1608<h3>
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]1609 <a name="ordering">Atomic Memory Ordering Constraints</a>
NAKAMURA Takumi0300d882011-08-12 06:17:17 +0000[diff] [blame]1610</h3>
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]1611
NAKAMURA Takumi0300d882011-08-12 06:17:17 +0000[diff] [blame]1612<div>
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]1613
1614<p>Atomic instructions (<a href="#i_cmpxchg"><code>cmpxchg</code></a>,
Eli Friedman59b66882011-08-09 23:02:53 +0000[diff] [blame]1615<a href="#i_atomicrmw"><code>atomicrmw</code></a>,
1616<a href="#i_fence"><code>fence</code></a>,
1617<a href="#i_load"><code>atomic load</code></a>, and
Eli Friedman75362532011-08-09 23:26:12 +0000[diff] [blame]1618<a href="#i_store"><code>atomic store</code></a>) take an ordering parameter
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]1619that determines which other atomic instructions on the same address they
1620<i>synchronize with</i>. These semantics are borrowed from Java and C++0x,
1621but are somewhat more colloquial. If these descriptions aren't precise enough,
Eli Friedman95f69a42011-08-22 21:35:27 +0000[diff] [blame]1622check those specs (see spec references in the
1623<a href="Atomic.html#introduction">atomics guide</a>).
1624<a href="#i_fence"><code>fence</code></a> instructions
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]1625treat these orderings somewhat differently since they don't take an address.
1626See that instruction's documentation for details.</p>
1627
Eli Friedman95f69a42011-08-22 21:35:27 +0000[diff] [blame]1628<p>For a simpler introduction to the ordering constraints, see the
1629<a href="Atomics.html">LLVM Atomic Instructions and Concurrency Guide</a>.</p>
1630
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]1631<dl>
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]1632<dt><code>unordered</code></dt>
1633<dd>The set of values that can be read is governed by the happens-before
1634partial order. A value cannot be read unless some operation wrote it.
1635This is intended to provide a guarantee strong enough to model Java's
1636non-volatile shared variables. This ordering cannot be specified for
1637read-modify-write operations; it is not strong enough to make them atomic
1638in any interesting way.</dd>
1639<dt><code>monotonic</code></dt>
1640<dd>In addition to the guarantees of <code>unordered</code>, there is a single
1641total order for modifications by <code>monotonic</code> operations on each
1642address. All modification orders must be compatible with the happens-before
1643order. There is no guarantee that the modification orders can be combined to
1644a global total order for the whole program (and this often will not be
1645possible). The read in an atomic read-modify-write operation
1646(<a href="#i_cmpxchg"><code>cmpxchg</code></a> and
1647<a href="#i_atomicrmw"><code>atomicrmw</code></a>)
1648reads the value in the modification order immediately before the value it
1649writes. If one atomic read happens before another atomic read of the same
1650address, the later read must see the same value or a later value in the
1651address's modification order. This disallows reordering of
1652<code>monotonic</code> (or stronger) operations on the same address. If an
1653address is written <code>monotonic</code>ally by one thread, and other threads
1654<code>monotonic</code>ally read that address repeatedly, the other threads must
Eli Friedman95f69a42011-08-22 21:35:27 +0000[diff] [blame]1655eventually see the write. This corresponds to the C++0x/C1x
1656<code>memory_order_relaxed</code>.</dd>
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]1657<dt><code>acquire</code></dt>
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]1658<dd>In addition to the guarantees of <code>monotonic</code>,
Eli Friedman0cb3b562011-08-24 20:28:39 +0000[diff] [blame]1659a <i>synchronizes-with</i> edge may be formed with a <code>release</code>
1660operation. This is intended to model C++'s <code>memory_order_acquire</code>.</dd>
1661<dt><code>release</code></dt>
1662<dd>In addition to the guarantees of <code>monotonic</code>, if this operation
1663writes a value which is subsequently read by an <code>acquire</code> operation,
1664it <i>synchronizes-with</i> that operation. (This isn't a complete
1665description; see the C++0x definition of a release sequence.) This corresponds
1666to the C++0x/C1x <code>memory_order_release</code>.</dd>
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]1667<dt><code>acq_rel</code> (acquire+release)</dt><dd>Acts as both an
Eli Friedman95f69a42011-08-22 21:35:27 +0000[diff] [blame]1668<code>acquire</code> and <code>release</code> operation on its address.
1669This corresponds to the C++0x/C1x <code>memory_order_acq_rel</code>.</dd>
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]1670<dt><code>seq_cst</code> (sequentially consistent)</dt><dd>
1671<dd>In addition to the guarantees of <code>acq_rel</code>
1672(<code>acquire</code> for an operation which only reads, <code>release</code>
1673for an operation which only writes), there is a global total order on all
1674sequentially-consistent operations on all addresses, which is consistent with
1675the <i>happens-before</i> partial order and with the modification orders of
1676all the affected addresses. Each sequentially-consistent read sees the last
Eli Friedman95f69a42011-08-22 21:35:27 +0000[diff] [blame]1677preceding write to the same address in this global order. This corresponds
1678to the C++0x/C1x <code>memory_order_seq_cst</code> and Java volatile.</dd>
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]1679</dl>
1680
1681<p id="singlethread">If an atomic operation is marked <code>singlethread</code>,
1682it only <i>synchronizes with</i> or participates in modification and seq_cst
1683total orderings with other operations running in the same thread (for example,
1684in signal handlers).</p>
1685
1686</div>
1687
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1688</div>
1689
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1690<!-- *********************************************************************** -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1691<h2><a name="typesystem">Type System</a></h2>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1692<!-- *********************************************************************** -->
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]1693
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1694<div>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]1695
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1696<p>The LLVM type system is one of the most important features of the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1697 intermediate representation. Being typed enables a number of optimizations
1698 to be performed on the intermediate representation directly, without having
1699 to do extra analyses on the side before the transformation. A strong type
1700 system makes it easier to read the generated code and enables novel analyses
1701 and transformations that are not feasible to perform on normal three address
1702 code representations.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]1703
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1704<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1705<h3>
1706 <a name="t_classifications">Type Classifications</a>
1707</h3>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1708
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1709<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1710
1711<p>The types fall into a few useful classifications:</p>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]1712
1713<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1714 <tbody>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1715 <tr><th>Classification</th><th>Types</th></tr>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1716 <tr>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1717 <td><a href="#t_integer">integer</a></td>
Reid Spencer138249b2007-05-16 18:44:01 +0000[diff] [blame]1718 <td><tt>i1, i2, i3, ... i8, ... i16, ... i32, ... i64, ... </tt></td>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1719 </tr>
1720 <tr>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1721 <td><a href="#t_floating">floating point</a></td>
1722 <td><tt>float, double, x86_fp80, fp128, ppc_fp128</tt></td>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1723 </tr>
1724 <tr>
1725 <td><a name="t_firstclass">first class</a></td>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1726 <td><a href="#t_integer">integer</a>,
1727 <a href="#t_floating">floating point</a>,
1728 <a href="#t_pointer">pointer</a>,
Dan Gohman08783a882008-06-18 18:42:13 +0000[diff] [blame]1729 <a href="#t_vector">vector</a>,
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]1730 <a href="#t_struct">structure</a>,
1731 <a href="#t_array">array</a>,
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1732 <a href="#t_label">label</a>,
1733 <a href="#t_metadata">metadata</a>.
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1734 </td>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1735 </tr>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1736 <tr>
1737 <td><a href="#t_primitive">primitive</a></td>
1738 <td><a href="#t_label">label</a>,
1739 <a href="#t_void">void</a>,
Tobias Grosser4c8c95b2010-12-28 20:29:31 +0000[diff] [blame]1740 <a href="#t_integer">integer</a>,
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1741 <a href="#t_floating">floating point</a>,
Dale Johannesen33e5c352010-10-01 00:48:59 +0000[diff] [blame]1742 <a href="#t_x86mmx">x86mmx</a>,
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1743 <a href="#t_metadata">metadata</a>.</td>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1744 </tr>
1745 <tr>
1746 <td><a href="#t_derived">derived</a></td>
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]1747 <td><a href="#t_array">array</a>,
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1748 <a href="#t_function">function</a>,
1749 <a href="#t_pointer">pointer</a>,
1750 <a href="#t_struct">structure</a>,
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1751 <a href="#t_vector">vector</a>,
1752 <a href="#t_opaque">opaque</a>.
Dan Gohman93bf60d2008-10-14 16:32:04 +0000[diff] [blame]1753 </td>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1754 </tr>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1755 </tbody>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1756</table>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]1757
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1758<p>The <a href="#t_firstclass">first class</a> types are perhaps the most
1759 important. Values of these types are the only ones which can be produced by
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]1760 instructions.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1761
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1762</div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1763
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1764<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1765<h3>
1766 <a name="t_primitive">Primitive Types</a>
1767</h3>
Chris Lattner43542b32008-01-04 04:34:14 +0000[diff] [blame]1768
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1769<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1770
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1771<p>The primitive types are the fundamental building blocks of the LLVM
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1772 system.</p>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1773
1774<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1775<h4>
1776 <a name="t_integer">Integer Type</a>
1777</h4>
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]1778
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1779<div>
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]1780
1781<h5>Overview:</h5>
1782<p>The integer type is a very simple type that simply specifies an arbitrary
1783 bit width for the integer type desired. Any bit width from 1 bit to
1784 2<sup>23</sup>-1 (about 8 million) can be specified.</p>
1785
1786<h5>Syntax:</h5>
1787<pre>
1788 iN
1789</pre>
1790
1791<p>The number of bits the integer will occupy is specified by the <tt>N</tt>
1792 value.</p>
1793
1794<h5>Examples:</h5>
1795<table class="layout">
1796 <tr class="layout">
1797 <td class="left"><tt>i1</tt></td>
1798 <td class="left">a single-bit integer.</td>
1799 </tr>
1800 <tr class="layout">
1801 <td class="left"><tt>i32</tt></td>
1802 <td class="left">a 32-bit integer.</td>
1803 </tr>
1804 <tr class="layout">
1805 <td class="left"><tt>i1942652</tt></td>
1806 <td class="left">a really big integer of over 1 million bits.</td>
1807 </tr>
1808</table>
1809
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]1810</div>
1811
1812<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1813<h4>
1814 <a name="t_floating">Floating Point Types</a>
1815</h4>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1816
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1817<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1818
1819<table>
1820 <tbody>
1821 <tr><th>Type</th><th>Description</th></tr>
1822 <tr><td><tt>float</tt></td><td>32-bit floating point value</td></tr>
1823 <tr><td><tt>double</tt></td><td>64-bit floating point value</td></tr>
1824 <tr><td><tt>fp128</tt></td><td>128-bit floating point value (112-bit mantissa)</td></tr>
1825 <tr><td><tt>x86_fp80</tt></td><td>80-bit floating point value (X87)</td></tr>
1826 <tr><td><tt>ppc_fp128</tt></td><td>128-bit floating point value (two 64-bits)</td></tr>
1827 </tbody>
1828</table>
1829
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1830</div>
1831
1832<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1833<h4>
1834 <a name="t_x86mmx">X86mmx Type</a>
1835</h4>
Dale Johannesen33e5c352010-10-01 00:48:59 +0000[diff] [blame]1836
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1837<div>
Dale Johannesen33e5c352010-10-01 00:48:59 +0000[diff] [blame]1838
1839<h5>Overview:</h5>
1840<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>
1841
1842<h5>Syntax:</h5>
1843<pre>
Dale Johannesenb1f0ff12010-10-01 01:07:02 +0000[diff] [blame]1844 x86mmx
Dale Johannesen33e5c352010-10-01 00:48:59 +0000[diff] [blame]1845</pre>
1846
1847</div>
1848
1849<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1850<h4>
1851 <a name="t_void">Void Type</a>
1852</h4>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1853
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1854<div>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1855
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1856<h5>Overview:</h5>
1857<p>The void type does not represent any value and has no size.</p>
1858
1859<h5>Syntax:</h5>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1860<pre>
1861 void
1862</pre>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1863
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1864</div>
1865
1866<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1867<h4>
1868 <a name="t_label">Label Type</a>
1869</h4>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1870
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1871<div>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1872
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1873<h5>Overview:</h5>
1874<p>The label type represents code labels.</p>
1875
1876<h5>Syntax:</h5>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1877<pre>
1878 label
1879</pre>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1880
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1881</div>
1882
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1883<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1884<h4>
1885 <a name="t_metadata">Metadata Type</a>
1886</h4>
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1887
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1888<div>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1889
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1890<h5>Overview:</h5>
Nick Lewycky93e06a52009-09-27 23:27:42 +0000[diff] [blame]1891<p>The metadata type represents embedded metadata. No derived types may be
1892 created from metadata except for <a href="#t_function">function</a>
1893 arguments.
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1894
1895<h5>Syntax:</h5>
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1896<pre>
1897 metadata
1898</pre>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1899
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1900</div>
1901
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1902</div>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1903
1904<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1905<h3>
1906 <a name="t_derived">Derived Types</a>
1907</h3>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1908
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1909<div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1910
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1911<p>The real power in LLVM comes from the derived types in the system. This is
1912 what allows a programmer to represent arrays, functions, pointers, and other
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]1913 useful types. Each of these types contain one or more element types which
1914 may be a primitive type, or another derived type. For example, it is
1915 possible to have a two dimensional array, using an array as the element type
1916 of another array.</p>
Dan Gohman142ccc02009-01-24 15:58:40 +0000[diff] [blame]1917
Chris Lattnerb1ed91f2011-07-09 17:41:24 +0000[diff] [blame]1918</div>
1919
1920
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]1921<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1922<h4>
1923 <a name="t_aggregate">Aggregate Types</a>
1924</h4>
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]1925
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1926<div>
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]1927
1928<p>Aggregate Types are a subset of derived types that can contain multiple
1929 member types. <a href="#t_array">Arrays</a>,
Chris Lattner13ee7952010-08-28 04:09:24 +0000[diff] [blame]1930 <a href="#t_struct">structs</a>, and <a href="#t_vector">vectors</a> are
1931 aggregate types.</p>
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]1932
1933</div>
1934
Reid Spencer138249b2007-05-16 18:44:01 +0000[diff] [blame]1935<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1936<h4>
1937 <a name="t_array">Array Type</a>
1938</h4>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1939
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1940<div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1941
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1942<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1943<p>The array type is a very simple derived type that arranges elements
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1944 sequentially in memory. The array type requires a size (number of elements)
1945 and an underlying data type.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1946
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]1947<h5>Syntax:</h5>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1948<pre>
1949 [&lt;# elements&gt; x &lt;elementtype&gt;]
1950</pre>
1951
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1952<p>The number of elements is a constant integer value; <tt>elementtype</tt> may
1953 be any type with a size.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1954
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]1955<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1956<table class="layout">
1957 <tr class="layout">
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]1958 <td class="left"><tt>[40 x i32]</tt></td>
1959 <td class="left">Array of 40 32-bit integer values.</td>
1960 </tr>
1961 <tr class="layout">
1962 <td class="left"><tt>[41 x i32]</tt></td>
1963 <td class="left">Array of 41 32-bit integer values.</td>
1964 </tr>
1965 <tr class="layout">
1966 <td class="left"><tt>[4 x i8]</tt></td>
1967 <td class="left">Array of 4 8-bit integer values.</td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1968 </tr>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1969</table>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1970<p>Here are some examples of multidimensional arrays:</p>
1971<table class="layout">
1972 <tr class="layout">
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]1973 <td class="left"><tt>[3 x [4 x i32]]</tt></td>
1974 <td class="left">3x4 array of 32-bit integer values.</td>
1975 </tr>
1976 <tr class="layout">
1977 <td class="left"><tt>[12 x [10 x float]]</tt></td>
1978 <td class="left">12x10 array of single precision floating point values.</td>
1979 </tr>
1980 <tr class="layout">
1981 <td class="left"><tt>[2 x [3 x [4 x i16]]]</tt></td>
1982 <td class="left">2x3x4 array of 16-bit integer values.</td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1983 </tr>
1984</table>
Chris Lattnerc0ad71e2005-06-24 17:22:57 +0000[diff] [blame]1985
Dan Gohmanc74bc282009-11-09 19:01:53 +0000[diff] [blame]1986<p>There is no restriction on indexing beyond the end of the array implied by
1987 a static type (though there are restrictions on indexing beyond the bounds
1988 of an allocated object in some cases). This means that single-dimension
1989 'variable sized array' addressing can be implemented in LLVM with a zero
1990 length array type. An implementation of 'pascal style arrays' in LLVM could
1991 use the type "<tt>{ i32, [0 x float]}</tt>", for example.</p>
Chris Lattnerc0ad71e2005-06-24 17:22:57 +0000[diff] [blame]1992
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1993</div>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1994
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1995<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1996<h4>
1997 <a name="t_function">Function Type</a>
1998</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1999
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2000<div>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]2001
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2002<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2003<p>The function type can be thought of as a function signature. It consists of
2004 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]2005 function type is a first class type or a void type.</p>
Devang Pateld6cff512008-03-10 20:49:15 +0000[diff] [blame]2006
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2007<h5>Syntax:</h5>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]2008<pre>
Nick Lewycky14d1ccc2009-09-27 07:55:32 +0000[diff] [blame]2009 &lt;returntype&gt; (&lt;parameter list&gt;)
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]2010</pre>
2011
John Criswell4c0cf7f2005-10-24 16:17:18 +0000[diff] [blame]2012<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]2013 specifiers. Optionally, the parameter list may include a type <tt>...</tt>,
2014 which indicates that the function takes a variable number of arguments.
2015 Variable argument functions can access their arguments with
2016 the <a href="#int_varargs">variable argument handling intrinsic</a>
Chris Lattner47f2a832010-03-02 06:36:51 +0000[diff] [blame]2017 functions. '<tt>&lt;returntype&gt;</tt>' is any type except
Nick Lewycky93e06a52009-09-27 23:27:42 +0000[diff] [blame]2018 <a href="#t_label">label</a>.</p>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]2019
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2020<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]2021<table class="layout">
2022 <tr class="layout">
Reid Spencer58c08712006-12-31 07:18:34 +0000[diff] [blame]2023 <td class="left"><tt>i32 (i32)</tt></td>
2024 <td class="left">function taking an <tt>i32</tt>, returning an <tt>i32</tt>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]2025 </td>
Reid Spencer58c08712006-12-31 07:18:34 +0000[diff] [blame]2026 </tr><tr class="layout">
Chris Lattner47f2a832010-03-02 06:36:51 +0000[diff] [blame]2027 <td class="left"><tt>float&nbsp;(i16,&nbsp;i32&nbsp;*)&nbsp;*
Reid Spencer655dcc62006-12-31 07:20:23 +0000[diff] [blame]2028 </tt></td>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]2029 <td class="left"><a href="#t_pointer">Pointer</a> to a function that takes
Chris Lattner47f2a832010-03-02 06:36:51 +0000[diff] [blame]2030 an <tt>i16</tt> and a <a href="#t_pointer">pointer</a> to <tt>i32</tt>,
2031 returning <tt>float</tt>.
Reid Spencer58c08712006-12-31 07:18:34 +0000[diff] [blame]2032 </td>
2033 </tr><tr class="layout">
2034 <td class="left"><tt>i32 (i8*, ...)</tt></td>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]2035 <td class="left">A vararg function that takes at least one
2036 <a href="#t_pointer">pointer</a> to <tt>i8 </tt> (char in C),
2037 which returns an integer. This is the signature for <tt>printf</tt> in
Reid Spencer58c08712006-12-31 07:18:34 +0000[diff] [blame]2038 LLVM.
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]2039 </td>
Devang Patele3dfc1c2008-03-24 05:35:41 +0000[diff] [blame]2040 </tr><tr class="layout">
2041 <td class="left"><tt>{i32, i32} (i32)</tt></td>
Nick Lewycky14d1ccc2009-09-27 07:55:32 +0000[diff] [blame]2042 <td class="left">A function taking an <tt>i32</tt>, returning a
2043 <a href="#t_struct">structure</a> containing two <tt>i32</tt> values
Devang Patele3dfc1c2008-03-24 05:35:41 +0000[diff] [blame]2044 </td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]2045 </tr>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2046</table>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]2047
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2048</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2049
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2050<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2051<h4>
2052 <a name="t_struct">Structure Type</a>
2053</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2054
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2055<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2056
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2057<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2058<p>The structure type is used to represent a collection of data members together
Chris Lattnerb1ed91f2011-07-09 17:41:24 +0000[diff] [blame]2059 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]2060
Jeffrey Yasskinf991bbb2010-01-11 19:19:26 +0000[diff] [blame]2061<p>Structures in memory are accessed using '<tt><a href="#i_load">load</a></tt>'
2062 and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a field
2063 with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.
2064 Structures in registers are accessed using the
2065 '<tt><a href="#i_extractvalue">extractvalue</a></tt>' and
2066 '<tt><a href="#i_insertvalue">insertvalue</a></tt>' instructions.</p>
Chris Lattnerb1ed91f2011-07-09 17:41:24 +0000[diff] [blame]2067
2068<p>Structures may optionally be "packed" structures, which indicate that the
2069 alignment of the struct is one byte, and that there is no padding between
Chris Lattner190552d2011-08-12 17:31:02 +0000[diff] [blame]2070 the elements. In non-packed structs, padding between field types is inserted
2071 as defined by the TargetData string in the module, which is required to match
Chris Lattner7bd0ea32011-10-11 23:02:17 +0000[diff] [blame^]2072 what the underlying code generator expects.</p>
Chris Lattnerb1ed91f2011-07-09 17:41:24 +0000[diff] [blame]2073
Chris Lattner190552d2011-08-12 17:31:02 +0000[diff] [blame]2074<p>Structures can either be "literal" or "identified". A literal structure is
2075 defined inline with other types (e.g. <tt>{i32, i32}*</tt>) whereas identified
2076 types are always defined at the top level with a name. Literal types are
2077 uniqued by their contents and can never be recursive or opaque since there is
Chris Lattner32531732011-08-12 18:12:40 +0000[diff] [blame]2078 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]2079 never uniqued.
Chris Lattnerb1ed91f2011-07-09 17:41:24 +0000[diff] [blame]2080</p>
2081
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2082<h5>Syntax:</h5>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]2083<pre>
Chris Lattner190552d2011-08-12 17:31:02 +0000[diff] [blame]2084 %T1 = type { &lt;type list&gt; } <i>; Identified normal struct type</i>
2085 %T2 = type &lt;{ &lt;type list&gt; }&gt; <i>; Identified packed struct type</i>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]2086</pre>
Chris Lattnerb1ed91f2011-07-09 17:41:24 +0000[diff] [blame]2087
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2088<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]2089<table class="layout">
2090 <tr class="layout">
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]2091 <td class="left"><tt>{ i32, i32, i32 }</tt></td>
2092 <td class="left">A triple of three <tt>i32</tt> values</td>
Chris Lattnerb1ed91f2011-07-09 17:41:24 +0000[diff] [blame]2093 </tr>
2094 <tr class="layout">
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]2095 <td class="left"><tt>{&nbsp;float,&nbsp;i32&nbsp;(i32)&nbsp;*&nbsp;}</tt></td>
2096 <td class="left">A pair, where the first element is a <tt>float</tt> and the
2097 second element is a <a href="#t_pointer">pointer</a> to a
2098 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
2099 an <tt>i32</tt>.</td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]2100 </tr>
Chris Lattnerb1ed91f2011-07-09 17:41:24 +0000[diff] [blame]2101 <tr class="layout">
2102 <td class="left"><tt>&lt;{ i8, i32 }&gt;</tt></td>
2103 <td class="left">A packed struct known to be 5 bytes in size.</td>
2104 </tr>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2105</table>
Dan Gohman142ccc02009-01-24 15:58:40 +0000[diff] [blame]2106
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2107</div>
Chris Lattnerb1ed91f2011-07-09 17:41:24 +0000[diff] [blame]2108
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2109<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2110<h4>
Chris Lattner2a843822011-07-23 19:59:08 +0000[diff] [blame]2111 <a name="t_opaque">Opaque Structure Types</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2112</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2113
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2114<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2115
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]2116<h5>Overview:</h5>
Chris Lattner2a843822011-07-23 19:59:08 +0000[diff] [blame]2117<p>Opaque structure types are used to represent named structure types that do
2118 not have a body specified. This corresponds (for example) to the C notion of
2119 a forward declared structure.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2120
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]2121<h5>Syntax:</h5>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]2122<pre>
Chris Lattnerb1ed91f2011-07-09 17:41:24 +0000[diff] [blame]2123 %X = type opaque
2124 %52 = type opaque
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]2125</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2126
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]2127<h5>Examples:</h5>
2128<table class="layout">
2129 <tr class="layout">
Chris Lattnerb1ed91f2011-07-09 17:41:24 +0000[diff] [blame]2130 <td class="left"><tt>opaque</tt></td>
2131 <td class="left">An opaque type.</td>
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]2132 </tr>
2133</table>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2134
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]2135</div>
2136
Chris Lattnerb1ed91f2011-07-09 17:41:24 +0000[diff] [blame]2137
2138
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]2139<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2140<h4>
2141 <a name="t_pointer">Pointer Type</a>
2142</h4>
Chris Lattner4a67c912009-02-08 19:53:29 +0000[diff] [blame]2143
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2144<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2145
2146<h5>Overview:</h5>
Dan Gohman88481112010-02-25 16:50:07 +0000[diff] [blame]2147<p>The pointer type is used to specify memory locations.
2148 Pointers are commonly used to reference objects in memory.</p>
2149
2150<p>Pointer types may have an optional address space attribute defining the
2151 numbered address space where the pointed-to object resides. The default
2152 address space is number zero. The semantics of non-zero address
2153 spaces are target-specific.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2154
2155<p>Note that LLVM does not permit pointers to void (<tt>void*</tt>) nor does it
2156 permit pointers to labels (<tt>label*</tt>). Use <tt>i8*</tt> instead.</p>
Chris Lattner4a67c912009-02-08 19:53:29 +0000[diff] [blame]2157
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]2158<h5>Syntax:</h5>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]2159<pre>
2160 &lt;type&gt; *
2161</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2162
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]2163<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]2164<table class="layout">
2165 <tr class="layout">
Dan Gohman623806e2009-01-04 23:44:43 +0000[diff] [blame]2166 <td class="left"><tt>[4 x i32]*</tt></td>
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]2167 <td class="left">A <a href="#t_pointer">pointer</a> to <a
2168 href="#t_array">array</a> of four <tt>i32</tt> values.</td>
2169 </tr>
2170 <tr class="layout">
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]2171 <td class="left"><tt>i32 (i32*) *</tt></td>
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]2172 <td class="left"> A <a href="#t_pointer">pointer</a> to a <a
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2173 href="#t_function">function</a> that takes an <tt>i32*</tt>, returning an
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]2174 <tt>i32</tt>.</td>
2175 </tr>
2176 <tr class="layout">
2177 <td class="left"><tt>i32 addrspace(5)*</tt></td>
2178 <td class="left">A <a href="#t_pointer">pointer</a> to an <tt>i32</tt> value
2179 that resides in address space #5.</td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]2180 </tr>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2181</table>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2182
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2183</div>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]2184
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]2185<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2186<h4>
2187 <a name="t_vector">Vector Type</a>
2188</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2189
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2190<div>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]2191
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]2192<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2193<p>A vector type is a simple derived type that represents a vector of elements.
2194 Vector types are used when multiple primitive data are operated in parallel
2195 using a single instruction (SIMD). A vector type requires a size (number of
Duncan Sands31c0e0e2009-11-27 13:38:03 +0000[diff] [blame]2196 elements) and an underlying primitive data type. Vector types are considered
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2197 <a href="#t_firstclass">first class</a>.</p>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]2198
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]2199<h5>Syntax:</h5>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]2200<pre>
2201 &lt; &lt;# elements&gt; x &lt;elementtype&gt; &gt;
2202</pre>
2203
Chris Lattnerf11031a2010-10-10 18:20:35 +0000[diff] [blame]2204<p>The number of elements is a constant integer value larger than 0; elementtype
2205 may be any integer or floating point type. Vectors of size zero are not
2206 allowed, and pointers are not allowed as the element type.</p>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]2207
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]2208<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]2209<table class="layout">
2210 <tr class="layout">
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]2211 <td class="left"><tt>&lt;4 x i32&gt;</tt></td>
2212 <td class="left">Vector of 4 32-bit integer values.</td>
2213 </tr>
2214 <tr class="layout">
2215 <td class="left"><tt>&lt;8 x float&gt;</tt></td>
2216 <td class="left">Vector of 8 32-bit floating-point values.</td>
2217 </tr>
2218 <tr class="layout">
2219 <td class="left"><tt>&lt;2 x i64&gt;</tt></td>
2220 <td class="left">Vector of 2 64-bit integer values.</td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]2221 </tr>
2222</table>
Dan Gohman142ccc02009-01-24 15:58:40 +0000[diff] [blame]2223
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2224</div>
2225
Bill Wendlingae8b5ea2011-07-31 06:47:33 +0000[diff] [blame]2226</div>
2227
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2228<!-- *********************************************************************** -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2229<h2><a name="constants">Constants</a></h2>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2230<!-- *********************************************************************** -->
2231
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2232<div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2233
2234<p>LLVM has several different basic types of constants. This section describes
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2235 them all and their syntax.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2236
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2237<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2238<h3>
2239 <a name="simpleconstants">Simple Constants</a>
2240</h3>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2241
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2242<div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2243
2244<dl>
2245 <dt><b>Boolean constants</b></dt>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2246 <dd>The two strings '<tt>true</tt>' and '<tt>false</tt>' are both valid
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]2247 constants of the <tt><a href="#t_integer">i1</a></tt> type.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2248
2249 <dt><b>Integer constants</b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2250 <dd>Standard integers (such as '4') are constants of
2251 the <a href="#t_integer">integer</a> type. Negative numbers may be used
2252 with integer types.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2253
2254 <dt><b>Floating point constants</b></dt>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2255 <dd>Floating point constants use standard decimal notation (e.g. 123.421),
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2256 exponential notation (e.g. 1.23421e+2), or a more precise hexadecimal
2257 notation (see below). The assembler requires the exact decimal value of a
2258 floating-point constant. For example, the assembler accepts 1.25 but
2259 rejects 1.3 because 1.3 is a repeating decimal in binary. Floating point
2260 constants must have a <a href="#t_floating">floating point</a> type. </dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2261
2262 <dt><b>Null pointer constants</b></dt>
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]2263 <dd>The identifier '<tt>null</tt>' is recognized as a null pointer constant
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2264 and must be of <a href="#t_pointer">pointer type</a>.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2265</dl>
2266
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2267<p>The one non-intuitive notation for constants is the hexadecimal form of
2268 floating point constants. For example, the form '<tt>double
2269 0x432ff973cafa8000</tt>' is equivalent to (but harder to read than)
2270 '<tt>double 4.5e+15</tt>'. The only time hexadecimal floating point
2271 constants are required (and the only time that they are generated by the
2272 disassembler) is when a floating point constant must be emitted but it cannot
2273 be represented as a decimal floating point number in a reasonable number of
2274 digits. For example, NaN's, infinities, and other special values are
2275 represented in their IEEE hexadecimal format so that assembly and disassembly
2276 do not cause any bits to change in the constants.</p>
2277
Dale Johannesencd4a3012009-02-11 22:14:51 +0000[diff] [blame]2278<p>When using the hexadecimal form, constants of types float and double are
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2279 represented using the 16-digit form shown above (which matches the IEEE754
2280 representation for double); float values must, however, be exactly
2281 representable as IEE754 single precision. Hexadecimal format is always used
2282 for long double, and there are three forms of long double. The 80-bit format
2283 used by x86 is represented as <tt>0xK</tt> followed by 20 hexadecimal digits.
2284 The 128-bit format used by PowerPC (two adjacent doubles) is represented
2285 by <tt>0xM</tt> followed by 32 hexadecimal digits. The IEEE 128-bit format
2286 is represented by <tt>0xL</tt> followed by 32 hexadecimal digits; no
2287 currently supported target uses this format. Long doubles will only work if
2288 they match the long double format on your target. All hexadecimal formats
2289 are big-endian (sign bit at the left).</p>
2290
Dale Johannesen33e5c352010-10-01 00:48:59 +0000[diff] [blame]2291<p>There are no constants of type x86mmx.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2292</div>
2293
2294<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2295<h3>
Bill Wendling972b7202009-07-20 02:32:41 +0000[diff] [blame]2296<a name="aggregateconstants"></a> <!-- old anchor -->
2297<a name="complexconstants">Complex Constants</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2298</h3>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2299
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2300<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2301
Chris Lattner361bfcd2009-02-28 18:32:25 +0000[diff] [blame]2302<p>Complex constants are a (potentially recursive) combination of simple
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2303 constants and smaller complex constants.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2304
2305<dl>
2306 <dt><b>Structure constants</b></dt>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2307 <dd>Structure constants are represented with notation similar to structure
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2308 type definitions (a comma separated list of elements, surrounded by braces
2309 (<tt>{}</tt>)). For example: "<tt>{ i32 4, float 17.0, i32* @G }</tt>",
2310 where "<tt>@G</tt>" is declared as "<tt>@G = external global i32</tt>".
2311 Structure constants must have <a href="#t_struct">structure type</a>, and
2312 the number and types of elements must match those specified by the
2313 type.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2314
2315 <dt><b>Array constants</b></dt>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2316 <dd>Array constants are represented with notation similar to array type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2317 definitions (a comma separated list of elements, surrounded by square
2318 brackets (<tt>[]</tt>)). For example: "<tt>[ i32 42, i32 11, i32 74
2319 ]</tt>". Array constants must have <a href="#t_array">array type</a>, and
2320 the number and types of elements must match those specified by the
2321 type.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2322
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]2323 <dt><b>Vector constants</b></dt>
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]2324 <dd>Vector constants are represented with notation similar to vector type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2325 definitions (a comma separated list of elements, surrounded by
2326 less-than/greater-than's (<tt>&lt;&gt;</tt>)). For example: "<tt>&lt; i32
2327 42, i32 11, i32 74, i32 100 &gt;</tt>". Vector constants must
2328 have <a href="#t_vector">vector type</a>, and the number and types of
2329 elements must match those specified by the type.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2330
2331 <dt><b>Zero initialization</b></dt>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2332 <dd>The string '<tt>zeroinitializer</tt>' can be used to zero initialize a
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]2333 value to zero of <em>any</em> type, including scalar and
2334 <a href="#t_aggregate">aggregate</a> types.
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2335 This is often used to avoid having to print large zero initializers
2336 (e.g. for large arrays) and is always exactly equivalent to using explicit
2337 zero initializers.</dd>
Nick Lewycky49f89192009-04-04 07:22:01 +0000[diff] [blame]2338
2339 <dt><b>Metadata node</b></dt>
Nick Lewycky8e2c4f42009-05-30 16:08:30 +0000[diff] [blame]2340 <dd>A metadata node is a structure-like constant with
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2341 <a href="#t_metadata">metadata type</a>. For example: "<tt>metadata !{
2342 i32 0, metadata !"test" }</tt>". Unlike other constants that are meant to
2343 be interpreted as part of the instruction stream, metadata is a place to
2344 attach additional information such as debug info.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2345</dl>
2346
2347</div>
2348
2349<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2350<h3>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2351 <a name="globalconstants">Global Variable and Function Addresses</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2352</h3>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2353
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2354<div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2355
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2356<p>The addresses of <a href="#globalvars">global variables</a>
2357 and <a href="#functionstructure">functions</a> are always implicitly valid
2358 (link-time) constants. These constants are explicitly referenced when
2359 the <a href="#identifiers">identifier for the global</a> is used and always
2360 have <a href="#t_pointer">pointer</a> type. For example, the following is a
2361 legal LLVM file:</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2362
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2363<pre class="doc_code">
Chris Lattner00538a12007-06-06 18:28:13 +0000[diff] [blame]2364@X = global i32 17
2365@Y = global i32 42
2366@Z = global [2 x i32*] [ i32* @X, i32* @Y ]
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2367</pre>
2368
2369</div>
2370
2371<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2372<h3>
2373 <a name="undefvalues">Undefined Values</a>
2374</h3>
2375
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2376<div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2377
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2378<p>The string '<tt>undef</tt>' can be used anywhere a constant is expected, and
Benjamin Kramer0f420382009-10-12 14:46:08 +0000[diff] [blame]2379 indicates that the user of the value may receive an unspecified bit-pattern.
Bill Wendling6bbe0912010-10-27 01:07:41 +0000[diff] [blame]2380 Undefined values may be of any type (other than '<tt>label</tt>'
2381 or '<tt>void</tt>') and be used anywhere a constant is permitted.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2382
Chris Lattner92ada5d2009-09-11 01:49:31 +0000[diff] [blame]2383<p>Undefined values are useful because they indicate to the compiler that the
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2384 program is well defined no matter what value is used. This gives the
2385 compiler more freedom to optimize. Here are some examples of (potentially
2386 surprising) transformations that are valid (in pseudo IR):</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2387
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 = add %X, undef
2391 %B = sub %X, undef
2392 %C = xor %X, undef
2393Safe:
2394 %A = undef
2395 %B = undef
2396 %C = undef
2397</pre>
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2398
2399<p>This is safe because all of the output bits are affected by the undef bits.
Bill Wendling6bbe0912010-10-27 01:07:41 +0000[diff] [blame]2400 Any output bit can have a zero or one depending on the input bits.</p>
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2401
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2402<pre class="doc_code">
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2403 %A = or %X, undef
2404 %B = and %X, undef
2405Safe:
2406 %A = -1
2407 %B = 0
2408Unsafe:
2409 %A = undef
2410 %B = undef
2411</pre>
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2412
2413<p>These logical operations have bits that are not always affected by the input.
Bill Wendling6bbe0912010-10-27 01:07:41 +0000[diff] [blame]2414 For example, if <tt>%X</tt> has a zero bit, then the output of the
2415 '<tt>and</tt>' operation will always be a zero for that bit, no matter what
2416 the corresponding bit from the '<tt>undef</tt>' is. As such, it is unsafe to
2417 optimize or assume that the result of the '<tt>and</tt>' is '<tt>undef</tt>'.
2418 However, it is safe to assume that all bits of the '<tt>undef</tt>' could be
2419 0, and optimize the '<tt>and</tt>' to 0. Likewise, it is safe to assume that
2420 all the bits of the '<tt>undef</tt>' operand to the '<tt>or</tt>' could be
2421 set, allowing the '<tt>or</tt>' to be folded to -1.</p>
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2422
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2423<pre class="doc_code">
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2424 %A = select undef, %X, %Y
2425 %B = select undef, 42, %Y
2426 %C = select %X, %Y, undef
2427Safe:
2428 %A = %X (or %Y)
2429 %B = 42 (or %Y)
2430 %C = %Y
2431Unsafe:
2432 %A = undef
2433 %B = undef
2434 %C = undef
2435</pre>
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2436
Bill Wendling6bbe0912010-10-27 01:07:41 +0000[diff] [blame]2437<p>This set of examples shows that undefined '<tt>select</tt>' (and conditional
2438 branch) conditions can go <em>either way</em>, but they have to come from one
2439 of the two operands. In the <tt>%A</tt> example, if <tt>%X</tt> and
2440 <tt>%Y</tt> were both known to have a clear low bit, then <tt>%A</tt> would
2441 have to have a cleared low bit. However, in the <tt>%C</tt> example, the
2442 optimizer is allowed to assume that the '<tt>undef</tt>' operand could be the
2443 same as <tt>%Y</tt>, allowing the whole '<tt>select</tt>' to be
2444 eliminated.</p>
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2445
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2446<pre class="doc_code">
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2447 %A = xor undef, undef
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]2448
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2449 %B = undef
2450 %C = xor %B, %B
2451
2452 %D = undef
2453 %E = icmp lt %D, 4
2454 %F = icmp gte %D, 4
2455
2456Safe:
2457 %A = undef
2458 %B = undef
2459 %C = undef
2460 %D = undef
2461 %E = undef
2462 %F = undef
2463</pre>
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2464
Bill Wendling6bbe0912010-10-27 01:07:41 +0000[diff] [blame]2465<p>This example points out that two '<tt>undef</tt>' operands are not
2466 necessarily the same. This can be surprising to people (and also matches C
2467 semantics) where they assume that "<tt>X^X</tt>" is always zero, even
2468 if <tt>X</tt> is undefined. This isn't true for a number of reasons, but the
2469 short answer is that an '<tt>undef</tt>' "variable" can arbitrarily change
2470 its value over its "live range". This is true because the variable doesn't
2471 actually <em>have a live range</em>. Instead, the value is logically read
2472 from arbitrary registers that happen to be around when needed, so the value
2473 is not necessarily consistent over time. In fact, <tt>%A</tt> and <tt>%C</tt>
2474 need to have the same semantics or the core LLVM "replace all uses with"
2475 concept would not hold.</p>
Chris Lattnera34a7182009-09-07 23:33:52 +0000[diff] [blame]2476
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2477<pre class="doc_code">
Chris Lattnera34a7182009-09-07 23:33:52 +0000[diff] [blame]2478 %A = fdiv undef, %X
2479 %B = fdiv %X, undef
2480Safe:
2481 %A = undef
2482b: unreachable
2483</pre>
Chris Lattnera34a7182009-09-07 23:33:52 +0000[diff] [blame]2484
2485<p>These examples show the crucial difference between an <em>undefined
Bill Wendling6bbe0912010-10-27 01:07:41 +0000[diff] [blame]2486 value</em> and <em>undefined behavior</em>. An undefined value (like
2487 '<tt>undef</tt>') is allowed to have an arbitrary bit-pattern. This means that
2488 the <tt>%A</tt> operation can be constant folded to '<tt>undef</tt>', because
2489 the '<tt>undef</tt>' could be an SNaN, and <tt>fdiv</tt> is not (currently)
2490 defined on SNaN's. However, in the second example, we can make a more
2491 aggressive assumption: because the <tt>undef</tt> is allowed to be an
2492 arbitrary value, we are allowed to assume that it could be zero. Since a
2493 divide by zero has <em>undefined behavior</em>, we are allowed to assume that
2494 the operation does not execute at all. This allows us to delete the divide and
2495 all code after it. Because the undefined operation "can't happen", the
2496 optimizer can assume that it occurs in dead code.</p>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]2497
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2498<pre class="doc_code">
Chris Lattnera34a7182009-09-07 23:33:52 +0000[diff] [blame]2499a: store undef -> %X
2500b: store %X -> undef
2501Safe:
2502a: &lt;deleted&gt;
2503b: unreachable
2504</pre>
Chris Lattnera34a7182009-09-07 23:33:52 +0000[diff] [blame]2505
Bill Wendling6bbe0912010-10-27 01:07:41 +0000[diff] [blame]2506<p>These examples reiterate the <tt>fdiv</tt> example: a store <em>of</em> an
2507 undefined value can be assumed to not have any effect; we can assume that the
2508 value is overwritten with bits that happen to match what was already there.
2509 However, a store <em>to</em> an undefined location could clobber arbitrary
2510 memory, therefore, it has undefined behavior.</p>
Chris Lattnera34a7182009-09-07 23:33:52 +0000[diff] [blame]2511
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2512</div>
2513
2514<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2515<h3>
2516 <a name="trapvalues">Trap Values</a>
2517</h3>
2518
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2519<div>
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]2520
Dan Gohmanb2a709b2010-04-26 20:21:21 +0000[diff] [blame]2521<p>Trap values are similar to <a href="#undefvalues">undef values</a>, however
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]2522 instead of representing an unspecified bit pattern, they represent the
2523 fact that an instruction or constant expression which cannot evoke side
2524 effects has nevertheless detected a condition which results in undefined
Dan Gohmanb2a709b2010-04-26 20:21:21 +0000[diff] [blame]2525 behavior.</p>
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]2526
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2527<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]2528 only exist when produced by operations such as
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2529 <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]2530
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2531<p>Trap value behavior is defined in terms of value <i>dependence</i>:</p>
Dan Gohmanb8b85c12010-04-26 23:36:52 +0000[diff] [blame]2532
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2533<ul>
2534<li>Values other than <a href="#i_phi"><tt>phi</tt></a> nodes depend on
2535 their operands.</li>
2536
2537<li><a href="#i_phi"><tt>Phi</tt></a> nodes depend on the operand corresponding
2538 to their dynamic predecessor basic block.</li>
2539
2540<li>Function arguments depend on the corresponding actual argument values in
2541 the dynamic callers of their functions.</li>
2542
2543<li><a href="#i_call"><tt>Call</tt></a> instructions depend on the
2544 <a href="#i_ret"><tt>ret</tt></a> instructions that dynamically transfer
2545 control back to them.</li>
2546
Dan Gohman7292a752010-05-03 14:55:22 +0000[diff] [blame]2547<li><a href="#i_invoke"><tt>Invoke</tt></a> instructions depend on the
2548 <a href="#i_ret"><tt>ret</tt></a>, <a href="#i_unwind"><tt>unwind</tt></a>,
2549 or exception-throwing call instructions that dynamically transfer control
2550 back to them.</li>
2551
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2552<li>Non-volatile loads and stores depend on the most recent stores to all of the
2553 referenced memory addresses, following the order in the IR
2554 (including loads and stores implied by intrinsics such as
2555 <a href="#int_memcpy"><tt>@llvm.memcpy</tt></a>.)</li>
2556
Dan Gohman3513ea52010-05-03 14:59:34 +0000[diff] [blame]2557<!-- TODO: In the case of multiple threads, this only applies if the store
2558 "happens-before" the load or store. -->
Dan Gohmanb8b85c12010-04-26 23:36:52 +0000[diff] [blame]2559
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2560<!-- TODO: floating-point exception state -->
Dan Gohmanb8b85c12010-04-26 23:36:52 +0000[diff] [blame]2561
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2562<li>An instruction with externally visible side effects depends on the most
2563 recent preceding instruction with externally visible side effects, following
Dan Gohman6c858db2010-07-06 15:26:33 +0000[diff] [blame]2564 the order in the IR. (This includes
2565 <a href="#volatile">volatile operations</a>.)</li>
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]2566
Dan Gohman7292a752010-05-03 14:55:22 +0000[diff] [blame]2567<li>An instruction <i>control-depends</i> on a
2568 <a href="#terminators">terminator instruction</a>
2569 if the terminator instruction has multiple successors and the instruction
2570 is always executed when control transfers to one of the successors, and
Chris Lattner0ab5e2c2011-04-15 05:18:47 +0000[diff] [blame]2571 may not be executed when control is transferred to another.</li>
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2572
Dan Gohmanc8454ee2011-04-12 23:05:59 +0000[diff] [blame]2573<li>Additionally, an instruction also <i>control-depends</i> on a terminator
2574 instruction if the set of instructions it otherwise depends on would be
Chris Lattner0ab5e2c2011-04-15 05:18:47 +0000[diff] [blame]2575 different if the terminator had transferred control to a different
Dan Gohmanc8454ee2011-04-12 23:05:59 +0000[diff] [blame]2576 successor.</li>
2577
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2578<li>Dependence is transitive.</li>
2579
2580</ul>
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2581
2582<p>Whenever a trap value is generated, all values which depend on it evaluate
2583 to trap. If they have side effects, the evoke their side effects as if each
2584 operand with a trap value were undef. If they have externally-visible side
2585 effects, the behavior is undefined.</p>
2586
2587<p>Here are some examples:</p>
Dan Gohman48a25882010-04-26 20:54:53 +0000[diff] [blame]2588
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2589<pre class="doc_code">
Dan Gohmanb8b85c12010-04-26 23:36:52 +0000[diff] [blame]2590entry:
2591 %trap = sub nuw i32 0, 1 ; Results in a trap value.
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2592 %still_trap = and i32 %trap, 0 ; Whereas (and i32 undef, 0) would return 0.
2593 %trap_yet_again = getelementptr i32* @h, i32 %still_trap
2594 store i32 0, i32* %trap_yet_again ; undefined behavior
2595
2596 store i32 %trap, i32* @g ; Trap value conceptually stored to memory.
2597 %trap2 = load i32* @g ; Returns a trap value, not just undef.
2598
2599 volatile store i32 %trap, i32* @g ; External observation; undefined behavior.
2600
2601 %narrowaddr = bitcast i32* @g to i16*
2602 %wideaddr = bitcast i32* @g to i64*
Nick Lewycky9c876bf2011-05-16 19:29:30 +0000[diff] [blame]2603 %trap3 = load i16* %narrowaddr ; Returns a trap value.
2604 %trap4 = load i64* %wideaddr ; Returns a trap value.
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2605
Nick Lewycky9c876bf2011-05-16 19:29:30 +0000[diff] [blame]2606 %cmp = icmp slt i32 %trap, 0 ; Returns a trap value.
2607 br i1 %cmp, label %true, label %end ; Branch to either destination.
Dan Gohmanb8b85c12010-04-26 23:36:52 +0000[diff] [blame]2608
2609true:
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2610 volatile store i32 0, i32* @g ; This is control-dependent on %cmp, so
2611 ; it has undefined behavior.
Dan Gohmanb8b85c12010-04-26 23:36:52 +0000[diff] [blame]2612 br label %end
2613
2614end:
2615 %p = phi i32 [ 0, %entry ], [ 1, %true ]
2616 ; Both edges into this PHI are
2617 ; control-dependent on %cmp, so this
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2618 ; always results in a trap value.
Dan Gohmanb8b85c12010-04-26 23:36:52 +0000[diff] [blame]2619
Dan Gohmanc8454ee2011-04-12 23:05:59 +0000[diff] [blame]2620 volatile store i32 0, i32* @g ; This would depend on the store in %true
2621 ; if %cmp is true, or the store in %entry
2622 ; otherwise, so this is undefined behavior.
2623
Nick Lewycky9c876bf2011-05-16 19:29:30 +0000[diff] [blame]2624 br i1 %cmp, label %second_true, label %second_end
Dan Gohmanc8454ee2011-04-12 23:05:59 +0000[diff] [blame]2625 ; The same branch again, but this time the
2626 ; true block doesn't have side effects.
2627
2628second_true:
2629 ; No side effects!
Nick Lewycky9c876bf2011-05-16 19:29:30 +0000[diff] [blame]2630 ret void
Dan Gohmanc8454ee2011-04-12 23:05:59 +0000[diff] [blame]2631
2632second_end:
2633 volatile store i32 0, i32* @g ; This time, the instruction always depends
2634 ; on the store in %end. Also, it is
2635 ; control-equivalent to %end, so this is
Nick Lewycky9c876bf2011-05-16 19:29:30 +0000[diff] [blame]2636 ; well-defined (again, ignoring earlier
Dan Gohmanb8b85c12010-04-26 23:36:52 +0000[diff] [blame]2637 ; undefined behavior in this example).
Dan Gohmanb8b85c12010-04-26 23:36:52 +0000[diff] [blame]2638</pre>
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]2639
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]2640</div>
2641
2642<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2643<h3>
2644 <a name="blockaddress">Addresses of Basic Blocks</a>
2645</h3>
2646
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2647<div>
Chris Lattnere4801f72009-10-27 21:01:34 +0000[diff] [blame]2648
Chris Lattneraa99c942009-11-01 01:27:45 +0000[diff] [blame]2649<p><b><tt>blockaddress(@function, %block)</tt></b></p>
Chris Lattnere4801f72009-10-27 21:01:34 +0000[diff] [blame]2650
2651<p>The '<tt>blockaddress</tt>' constant computes the address of the specified
Chris Lattner5c5f0ac2009-10-27 21:49:40 +0000[diff] [blame]2652 basic block in the specified function, and always has an i8* type. Taking
Chris Lattneraa99c942009-11-01 01:27:45 +0000[diff] [blame]2653 the address of the entry block is illegal.</p>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]2654
Chris Lattnere4801f72009-10-27 21:01:34 +0000[diff] [blame]2655<p>This value only has defined behavior when used as an operand to the
Bill Wendling6bbe0912010-10-27 01:07:41 +0000[diff] [blame]2656 '<a href="#i_indirectbr"><tt>indirectbr</tt></a>' instruction, or for
2657 comparisons against null. Pointer equality tests between labels addresses
2658 results in undefined behavior &mdash; though, again, comparison against null
2659 is ok, and no label is equal to the null pointer. This may be passed around
2660 as an opaque pointer sized value as long as the bits are not inspected. This
2661 allows <tt>ptrtoint</tt> and arithmetic to be performed on these values so
2662 long as the original value is reconstituted before the <tt>indirectbr</tt>
2663 instruction.</p>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]2664
Bill Wendling6bbe0912010-10-27 01:07:41 +0000[diff] [blame]2665<p>Finally, some targets may provide defined semantics when using the value as
2666 the operand to an inline assembly, but that is target specific.</p>
Chris Lattnere4801f72009-10-27 21:01:34 +0000[diff] [blame]2667
2668</div>
2669
2670
2671<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2672<h3>
2673 <a name="constantexprs">Constant Expressions</a>
2674</h3>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2675
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2676<div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2677
2678<p>Constant expressions are used to allow expressions involving other constants
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2679 to be used as constants. Constant expressions may be of
2680 any <a href="#t_firstclass">first class</a> type and may involve any LLVM
2681 operation that does not have side effects (e.g. load and call are not
Bill Wendling6bbe0912010-10-27 01:07:41 +0000[diff] [blame]2682 supported). The following is the syntax for constant expressions:</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2683
2684<dl>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2685 <dt><b><tt>trunc (CST to TYPE)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2686 <dd>Truncate a constant to another type. The bit size of CST must be larger
2687 than the bit size of TYPE. Both types must be integers.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2688
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2689 <dt><b><tt>zext (CST to TYPE)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2690 <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]2691 smaller than the bit size of TYPE. Both types must be integers.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2692
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2693 <dt><b><tt>sext (CST to TYPE)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2694 <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]2695 smaller than the bit size of TYPE. Both types must be integers.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2696
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2697 <dt><b><tt>fptrunc (CST to TYPE)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2698 <dd>Truncate a floating point constant to another floating point type. The
2699 size of CST must be larger than the size of TYPE. Both types must be
2700 floating point.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2701
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2702 <dt><b><tt>fpext (CST to TYPE)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2703 <dd>Floating point extend a constant to another type. The size of CST must be
2704 smaller or equal to the size of TYPE. Both types must be floating
2705 point.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2706
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2707 <dt><b><tt>fptoui (CST to TYPE)</tt></b></dt>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2708 <dd>Convert a floating point constant to the corresponding unsigned integer
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2709 constant. TYPE must be a scalar or vector integer type. CST must be of
2710 scalar or vector floating point type. Both CST and TYPE must be scalars,
2711 or vectors of the same number of elements. If the value won't fit in the
2712 integer type, the results are undefined.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2713
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2714 <dt><b><tt>fptosi (CST to TYPE)</tt></b></dt>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2715 <dd>Convert a floating point constant to the corresponding signed integer
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2716 constant. TYPE must be a scalar or vector integer type. CST must be of
2717 scalar or vector floating point type. Both CST and TYPE must be scalars,
2718 or vectors of the same number of elements. If the value won't fit in the
2719 integer type, the results are undefined.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2720
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2721 <dt><b><tt>uitofp (CST to TYPE)</tt></b></dt>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2722 <dd>Convert an unsigned integer constant to the corresponding floating point
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2723 constant. TYPE must be a scalar or vector floating point type. CST must be
2724 of scalar or vector integer type. Both CST and TYPE must be scalars, or
2725 vectors of the same number of elements. If the value won't fit in the
2726 floating point type, the results are undefined.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2727
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2728 <dt><b><tt>sitofp (CST to TYPE)</tt></b></dt>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2729 <dd>Convert a signed integer constant to the corresponding floating point
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2730 constant. TYPE must be a scalar or vector floating point type. CST must be
2731 of scalar or vector integer type. Both CST and TYPE must be scalars, or
2732 vectors of the same number of elements. If the value won't fit in the
2733 floating point type, the results are undefined.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2734
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2735 <dt><b><tt>ptrtoint (CST to TYPE)</tt></b></dt>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]2736 <dd>Convert a pointer typed constant to the corresponding integer constant
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2737 <tt>TYPE</tt> must be an integer type. <tt>CST</tt> must be of pointer
2738 type. The <tt>CST</tt> value is zero extended, truncated, or unchanged to
2739 make it fit in <tt>TYPE</tt>.</dd>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]2740
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2741 <dt><b><tt>inttoptr (CST to TYPE)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2742 <dd>Convert a integer constant to a pointer constant. TYPE must be a pointer
2743 type. CST must be of integer type. The CST value is zero extended,
2744 truncated, or unchanged to make it fit in a pointer size. This one is
2745 <i>really</i> dangerous!</dd>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]2746
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2747 <dt><b><tt>bitcast (CST to TYPE)</tt></b></dt>
Chris Lattner789dee32009-02-28 18:27:03 +0000[diff] [blame]2748 <dd>Convert a constant, CST, to another TYPE. The constraints of the operands
2749 are the same as those for the <a href="#i_bitcast">bitcast
2750 instruction</a>.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2751
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2752 <dt><b><tt>getelementptr (CSTPTR, IDX0, IDX1, ...)</tt></b></dt>
2753 <dt><b><tt>getelementptr inbounds (CSTPTR, IDX0, IDX1, ...)</tt></b></dt>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2754 <dd>Perform the <a href="#i_getelementptr">getelementptr operation</a> on
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2755 constants. As with the <a href="#i_getelementptr">getelementptr</a>
2756 instruction, the index list may have zero or more indexes, which are
2757 required to make sense for the type of "CSTPTR".</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2758
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2759 <dt><b><tt>select (COND, VAL1, VAL2)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2760 <dd>Perform the <a href="#i_select">select operation</a> on constants.</dd>
Reid Spencer9965ee72006-12-04 19:23:19 +0000[diff] [blame]2761
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2762 <dt><b><tt>icmp COND (VAL1, VAL2)</tt></b></dt>
Reid Spencer9965ee72006-12-04 19:23:19 +0000[diff] [blame]2763 <dd>Performs the <a href="#i_icmp">icmp operation</a> on constants.</dd>
2764
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2765 <dt><b><tt>fcmp COND (VAL1, VAL2)</tt></b></dt>
Reid Spencer9965ee72006-12-04 19:23:19 +0000[diff] [blame]2766 <dd>Performs the <a href="#i_fcmp">fcmp operation</a> on constants.</dd>
Robert Bocchino7e97a6d2006-01-10 19:31:34 +0000[diff] [blame]2767
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2768 <dt><b><tt>extractelement (VAL, IDX)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2769 <dd>Perform the <a href="#i_extractelement">extractelement operation</a> on
2770 constants.</dd>
Robert Bocchino7e97a6d2006-01-10 19:31:34 +0000[diff] [blame]2771
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2772 <dt><b><tt>insertelement (VAL, ELT, IDX)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2773 <dd>Perform the <a href="#i_insertelement">insertelement operation</a> on
2774 constants.</dd>
Chris Lattner016a0e52006-04-08 00:13:41 +0000[diff] [blame]2775
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2776 <dt><b><tt>shufflevector (VEC1, VEC2, IDXMASK)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2777 <dd>Perform the <a href="#i_shufflevector">shufflevector operation</a> on
2778 constants.</dd>
Chris Lattner016a0e52006-04-08 00:13:41 +0000[diff] [blame]2779
Nick Lewycky9ab9a7f2010-05-29 06:44:15 +0000[diff] [blame]2780 <dt><b><tt>extractvalue (VAL, IDX0, IDX1, ...)</tt></b></dt>
2781 <dd>Perform the <a href="#i_extractvalue">extractvalue operation</a> on
2782 constants. The index list is interpreted in a similar manner as indices in
2783 a '<a href="#i_getelementptr">getelementptr</a>' operation. At least one
2784 index value must be specified.</dd>
2785
2786 <dt><b><tt>insertvalue (VAL, ELT, IDX0, IDX1, ...)</tt></b></dt>
2787 <dd>Perform the <a href="#i_insertvalue">insertvalue operation</a> on
2788 constants. The index list is interpreted in a similar manner as indices in
2789 a '<a href="#i_getelementptr">getelementptr</a>' operation. At least one
2790 index value must be specified.</dd>
2791
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2792 <dt><b><tt>OPCODE (LHS, RHS)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2793 <dd>Perform the specified operation of the LHS and RHS constants. OPCODE may
2794 be any of the <a href="#binaryops">binary</a>
2795 or <a href="#bitwiseops">bitwise binary</a> operations. The constraints
2796 on operands are the same as those for the corresponding instruction
2797 (e.g. no bitwise operations on floating point values are allowed).</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2798</dl>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2799
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2800</div>
Chris Lattnerb1652612004-03-08 16:49:10 +0000[diff] [blame]2801
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2802</div>
2803
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2804<!-- *********************************************************************** -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2805<h2><a name="othervalues">Other Values</a></h2>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2806<!-- *********************************************************************** -->
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2807<div>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2808<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2809<h3>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2810<a name="inlineasm">Inline Assembler Expressions</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2811</h3>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2812
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2813<div>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2814
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2815<p>LLVM supports inline assembler expressions (as opposed
2816 to <a href="#moduleasm"> Module-Level Inline Assembly</a>) through the use of
2817 a special value. This value represents the inline assembler as a string
2818 (containing the instructions to emit), a list of operand constraints (stored
Dale Johannesen63c94fe2009-10-13 21:56:55 +0000[diff] [blame]2819 as a string), a flag that indicates whether or not the inline asm
Dale Johannesen1cfb9582009-10-21 23:28:00 +0000[diff] [blame]2820 expression has side effects, and a flag indicating whether the function
2821 containing the asm needs to align its stack conservatively. An example
2822 inline assembler expression is:</p>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2823
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2824<pre class="doc_code">
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2825i32 (i32) asm "bswap $0", "=r,r"
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2826</pre>
2827
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2828<p>Inline assembler expressions may <b>only</b> be used as the callee operand of
2829 a <a href="#i_call"><tt>call</tt> instruction</a>. Thus, typically we
2830 have:</p>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2831
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2832<pre class="doc_code">
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2833%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]2834</pre>
2835
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2836<p>Inline asms with side effects not visible in the constraint list must be
2837 marked as having side effects. This is done through the use of the
2838 '<tt>sideeffect</tt>' keyword, like so:</p>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2839
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2840<pre class="doc_code">
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2841call void asm sideeffect "eieio", ""()
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2842</pre>
2843
Dale Johannesen1cfb9582009-10-21 23:28:00 +0000[diff] [blame]2844<p>In some cases inline asms will contain code that will not work unless the
2845 stack is aligned in some way, such as calls or SSE instructions on x86,
2846 yet will not contain code that does that alignment within the asm.
2847 The compiler should make conservative assumptions about what the asm might
2848 contain and should generate its usual stack alignment code in the prologue
2849 if the '<tt>alignstack</tt>' keyword is present:</p>
Dale Johannesen63c94fe2009-10-13 21:56:55 +0000[diff] [blame]2850
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2851<pre class="doc_code">
Dale Johannesen1cfb9582009-10-21 23:28:00 +0000[diff] [blame]2852call void asm alignstack "eieio", ""()
Dale Johannesen63c94fe2009-10-13 21:56:55 +0000[diff] [blame]2853</pre>
Dale Johannesen63c94fe2009-10-13 21:56:55 +0000[diff] [blame]2854
2855<p>If both keywords appear the '<tt>sideeffect</tt>' keyword must come
2856 first.</p>
2857
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2858<p>TODO: The format of the asm and constraints string still need to be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2859 documented here. Constraints on what can be done (e.g. duplication, moving,
2860 etc need to be documented). This is probably best done by reference to
2861 another document that covers inline asm from a holistic perspective.</p>
Chris Lattner51065562010-04-07 05:38:05 +0000[diff] [blame]2862
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2863<h4>
Chris Lattner51065562010-04-07 05:38:05 +0000[diff] [blame]2864<a name="inlineasm_md">Inline Asm Metadata</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2865</h4>
Chris Lattner51065562010-04-07 05:38:05 +0000[diff] [blame]2866
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2867<div>
Chris Lattner51065562010-04-07 05:38:05 +0000[diff] [blame]2868
2869<p>The call instructions that wrap inline asm nodes may have a "!srcloc" MDNode
Chris Lattner79ffdc72010-11-17 08:20:42 +0000[diff] [blame]2870 attached to it that contains a list of constant integers. If present, the
2871 code generator will use the integer as the location cookie value when report
Chris Lattner51065562010-04-07 05:38:05 +0000[diff] [blame]2872 errors through the LLVMContext error reporting mechanisms. This allows a
Dan Gohman61110ae2010-04-28 00:36:01 +0000[diff] [blame]2873 front-end to correlate backend errors that occur with inline asm back to the
Chris Lattner51065562010-04-07 05:38:05 +0000[diff] [blame]2874 source code that produced it. For example:</p>
2875
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2876<pre class="doc_code">
Chris Lattner51065562010-04-07 05:38:05 +0000[diff] [blame]2877call void asm sideeffect "something bad", ""()<b>, !srcloc !42</b>
2878...
2879!42 = !{ i32 1234567 }
2880</pre>
Chris Lattner51065562010-04-07 05:38:05 +0000[diff] [blame]2881
2882<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]2883 IR. If the MDNode contains multiple constants, the code generator will use
2884 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]2885
2886</div>
2887
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2888</div>
2889
Chris Lattnerc2f8f162010-01-15 21:50:19 +0000[diff] [blame]2890<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2891<h3>
2892 <a name="metadata">Metadata Nodes and Metadata Strings</a>
2893</h3>
Chris Lattnerc2f8f162010-01-15 21:50:19 +0000[diff] [blame]2894
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2895<div>
Chris Lattnerc2f8f162010-01-15 21:50:19 +0000[diff] [blame]2896
2897<p>LLVM IR allows metadata to be attached to instructions in the program that
2898 can convey extra information about the code to the optimizers and code
2899 generator. One example application of metadata is source-level debug
2900 information. There are two metadata primitives: strings and nodes. All
2901 metadata has the <tt>metadata</tt> type and is identified in syntax by a
2902 preceding exclamation point ('<tt>!</tt>').</p>
2903
2904<p>A metadata string is a string surrounded by double quotes. It can contain
2905 any character by escaping non-printable characters with "\xx" where "xx" is
2906 the two digit hex code. For example: "<tt>!"test\00"</tt>".</p>
2907
2908<p>Metadata nodes are represented with notation similar to structure constants
2909 (a comma separated list of elements, surrounded by braces and preceded by an
2910 exclamation point). For example: "<tt>!{ metadata !"test\00", i32
2911 10}</tt>". Metadata nodes can have any values as their operand.</p>
2912
2913<p>A <a href="#namedmetadatastructure">named metadata</a> is a collection of
2914 metadata nodes, which can be looked up in the module symbol table. For
2915 example: "<tt>!foo = metadata !{!4, !3}</tt>".
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>
Benjamin Kramer79698be2010-07-13 12:26:09 +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
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2927 attached with <tt>add</tt> instruction using <tt>!dbg</tt> identifier.</p>
Devang Patel9984bd62010-03-04 23:44:48 +0000[diff] [blame]2928
Bill Wendlingc0e10672011-03-02 02:17:11 +0000[diff] [blame]2929<div class="doc_code">
2930<pre>
2931%indvar.next = add i64 %indvar, 1, !dbg !21
2932</pre>
2933</div>
2934
Chris Lattnerc2f8f162010-01-15 21:50:19 +0000[diff] [blame]2935</div>
2936
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2937</div>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]2938
2939<!-- *********************************************************************** -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2940<h2>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]2941 <a name="intrinsic_globals">Intrinsic Global Variables</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2942</h2>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]2943<!-- *********************************************************************** -->
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2944<div>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]2945<p>LLVM has a number of "magic" global variables that contain data that affect
2946code generation or other IR semantics. These are documented here. All globals
Chris Lattner58f9bb22009-07-20 06:14:25 +0000[diff] [blame]2947of this sort should have a section specified as "<tt>llvm.metadata</tt>". This
2948section and all globals that start with "<tt>llvm.</tt>" are reserved for use
2949by LLVM.</p>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]2950
2951<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2952<h3>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]2953<a name="intg_used">The '<tt>llvm.used</tt>' Global Variable</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2954</h3>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]2955
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2956<div>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]2957
2958<p>The <tt>@llvm.used</tt> global is an array with i8* element type which has <a
2959href="#linkage_appending">appending linkage</a>. This array contains a list of
2960pointers to global variables and functions which may optionally have a pointer
2961cast formed of bitcast or getelementptr. For example, a legal use of it is:</p>
2962
2963<pre>
2964 @X = global i8 4
2965 @Y = global i32 123
2966
2967 @llvm.used = appending global [2 x i8*] [
2968 i8* @X,
2969 i8* bitcast (i32* @Y to i8*)
2970 ], section "llvm.metadata"
2971</pre>
2972
2973<p>If a global variable appears in the <tt>@llvm.used</tt> list, then the
2974compiler, assembler, and linker are required to treat the symbol as if there is
2975a reference to the global that it cannot see. For example, if a variable has
2976internal linkage and no references other than that from the <tt>@llvm.used</tt>
2977list, it cannot be deleted. This is commonly used to represent references from
2978inline asms and other things the compiler cannot "see", and corresponds to
2979"attribute((used))" in GNU C.</p>
2980
2981<p>On some targets, the code generator must emit a directive to the assembler or
2982object file to prevent the assembler and linker from molesting the symbol.</p>
2983
2984</div>
2985
2986<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2987<h3>
2988 <a name="intg_compiler_used">
2989 The '<tt>llvm.compiler.used</tt>' Global Variable
2990 </a>
2991</h3>
Chris Lattner58f9bb22009-07-20 06:14:25 +0000[diff] [blame]2992
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2993<div>
Chris Lattner58f9bb22009-07-20 06:14:25 +0000[diff] [blame]2994
2995<p>The <tt>@llvm.compiler.used</tt> directive is the same as the
2996<tt>@llvm.used</tt> directive, except that it only prevents the compiler from
2997touching the symbol. On targets that support it, this allows an intelligent
2998linker to optimize references to the symbol without being impeded as it would be
2999by <tt>@llvm.used</tt>.</p>
3000
3001<p>This is a rare construct that should only be used in rare circumstances, and
3002should not be exposed to source languages.</p>
3003
3004</div>
3005
3006<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3007<h3>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]3008<a name="intg_global_ctors">The '<tt>llvm.global_ctors</tt>' Global Variable</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3009</h3>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]3010
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3011<div>
David Chisnalla9d4a6f2010-04-30 19:23:49 +0000[diff] [blame]3012<pre>
3013%0 = type { i32, void ()* }
David Chisnallb492b812010-04-30 19:27:35 +0000[diff] [blame]3014@llvm.global_ctors = appending global [1 x %0] [%0 { i32 65535, void ()* @ctor }]
David Chisnalla9d4a6f2010-04-30 19:23:49 +0000[diff] [blame]3015</pre>
3016<p>The <tt>@llvm.global_ctors</tt> array contains a list of constructor functions and associated priorities. The functions referenced by this array will be called in ascending order of priority (i.e. lowest first) when the module is loaded. The order of functions with the same priority is not defined.
3017</p>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]3018
3019</div>
3020
3021<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3022<h3>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]3023<a name="intg_global_dtors">The '<tt>llvm.global_dtors</tt>' Global Variable</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3024</h3>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]3025
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3026<div>
David Chisnalla9d4a6f2010-04-30 19:23:49 +0000[diff] [blame]3027<pre>
3028%0 = type { i32, void ()* }
David Chisnallb492b812010-04-30 19:27:35 +0000[diff] [blame]3029@llvm.global_dtors = appending global [1 x %0] [%0 { i32 65535, void ()* @dtor }]
David Chisnalla9d4a6f2010-04-30 19:23:49 +0000[diff] [blame]3030</pre>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]3031
David Chisnalla9d4a6f2010-04-30 19:23:49 +0000[diff] [blame]3032<p>The <tt>@llvm.global_dtors</tt> array contains a list of destructor functions and associated priorities. The functions referenced by this array will be called in descending order of priority (i.e. highest first) when the module is loaded. The order of functions with the same priority is not defined.
3033</p>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]3034
3035</div>
3036
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3037</div>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]3038
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]3039<!-- *********************************************************************** -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3040<h2><a name="instref">Instruction Reference</a></h2>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3041<!-- *********************************************************************** -->
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]3042
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3043<div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]3044
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3045<p>The LLVM instruction set consists of several different classifications of
3046 instructions: <a href="#terminators">terminator
3047 instructions</a>, <a href="#binaryops">binary instructions</a>,
3048 <a href="#bitwiseops">bitwise binary instructions</a>,
3049 <a href="#memoryops">memory instructions</a>, and
3050 <a href="#otherops">other instructions</a>.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]3051
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3052<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3053<h3>
3054 <a name="terminators">Terminator Instructions</a>
3055</h3>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]3056
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3057<div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]3058
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3059<p>As mentioned <a href="#functionstructure">previously</a>, every basic block
3060 in a program ends with a "Terminator" instruction, which indicates which
3061 block should be executed after the current block is finished. These
3062 terminator instructions typically yield a '<tt>void</tt>' value: they produce
3063 control flow, not values (the one exception being the
3064 '<a href="#i_invoke"><tt>invoke</tt></a>' instruction).</p>
3065
Chris Lattnerd3d65ab2011-08-02 20:29:13 +0000[diff] [blame]3066<p>The terminator instructions are:
3067 '<a href="#i_ret"><tt>ret</tt></a>',
3068 '<a href="#i_br"><tt>br</tt></a>',
3069 '<a href="#i_switch"><tt>switch</tt></a>',
3070 '<a href="#i_indirectbr"><tt>indirectbr</tt></a>',
3071 '<a href="#i_invoke"><tt>invoke</tt></a>',
3072 '<a href="#i_unwind"><tt>unwind</tt></a>',
3073 '<a href="#i_resume"><tt>resume</tt></a>', and
3074 '<a href="#i_unreachable"><tt>unreachable</tt></a>'.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]3075
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3076<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3077<h4>
3078 <a name="i_ret">'<tt>ret</tt>' Instruction</a>
3079</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3080
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3081<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3082
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3083<h5>Syntax:</h5>
Dan Gohmancc3132e2008-10-04 19:00:07 +0000[diff] [blame]3084<pre>
3085 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]3086 ret void <i>; Return from void function</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3087</pre>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]3088
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3089<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3090<p>The '<tt>ret</tt>' instruction is used to return control flow (and optionally
3091 a value) from a function back to the caller.</p>
3092
3093<p>There are two forms of the '<tt>ret</tt>' instruction: one that returns a
3094 value and then causes control flow, and one that just causes control flow to
3095 occur.</p>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]3096
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3097<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3098<p>The '<tt>ret</tt>' instruction optionally accepts a single argument, the
3099 return value. The type of the return value must be a
3100 '<a href="#t_firstclass">first class</a>' type.</p>
Dan Gohmancc3132e2008-10-04 19:00:07 +0000[diff] [blame]3101
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3102<p>A function is not <a href="#wellformed">well formed</a> if it it has a
3103 non-void return type and contains a '<tt>ret</tt>' instruction with no return
3104 value or a return value with a type that does not match its type, or if it
3105 has a void return type and contains a '<tt>ret</tt>' instruction with a
3106 return value.</p>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]3107
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3108<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3109<p>When the '<tt>ret</tt>' instruction is executed, control flow returns back to
3110 the calling function's context. If the caller is a
3111 "<a href="#i_call"><tt>call</tt></a>" instruction, execution continues at the
3112 instruction after the call. If the caller was an
3113 "<a href="#i_invoke"><tt>invoke</tt></a>" instruction, execution continues at
3114 the beginning of the "normal" destination block. If the instruction returns
3115 a value, that value shall set the call or invoke instruction's return
3116 value.</p>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]3117
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3118<h5>Example:</h5>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]3119<pre>
3120 ret i32 5 <i>; Return an integer value of 5</i>
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]3121 ret void <i>; Return from a void function</i>
Bill Wendling050ee8f2009-02-28 22:12:54 +0000[diff] [blame]3122 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]3123</pre>
Dan Gohman3065b612009-01-12 23:12:39 +0000[diff] [blame]3124
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3125</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3126<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3127<h4>
3128 <a name="i_br">'<tt>br</tt>' Instruction</a>
3129</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3130
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3131<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3132
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3133<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3134<pre>
Bill Wendling16b86742011-07-26 10:41:15 +0000[diff] [blame]3135 br i1 &lt;cond&gt;, label &lt;iftrue&gt;, label &lt;iffalse&gt;
3136 br label &lt;dest&gt; <i>; Unconditional branch</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3137</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3138
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3139<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3140<p>The '<tt>br</tt>' instruction is used to cause control flow to transfer to a
3141 different basic block in the current function. There are two forms of this
3142 instruction, corresponding to a conditional branch and an unconditional
3143 branch.</p>
3144
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3145<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3146<p>The conditional branch form of the '<tt>br</tt>' instruction takes a single
3147 '<tt>i1</tt>' value and two '<tt>label</tt>' values. The unconditional form
3148 of the '<tt>br</tt>' instruction takes a single '<tt>label</tt>' value as a
3149 target.</p>
3150
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3151<h5>Semantics:</h5>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]3152<p>Upon execution of a conditional '<tt>br</tt>' instruction, the '<tt>i1</tt>'
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3153 argument is evaluated. If the value is <tt>true</tt>, control flows to the
3154 '<tt>iftrue</tt>' <tt>label</tt> argument. If "cond" is <tt>false</tt>,
3155 control flows to the '<tt>iffalse</tt>' <tt>label</tt> argument.</p>
3156
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3157<h5>Example:</h5>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]3158<pre>
3159Test:
3160 %cond = <a href="#i_icmp">icmp</a> eq i32 %a, %b
3161 br i1 %cond, label %IfEqual, label %IfUnequal
3162IfEqual:
3163 <a href="#i_ret">ret</a> i32 1
3164IfUnequal:
3165 <a href="#i_ret">ret</a> i32 0
3166</pre>
3167
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3168</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3169
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3170<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3171<h4>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]3172 <a name="i_switch">'<tt>switch</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3173</h4>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]3174
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3175<div>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]3176
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3177<h5>Syntax:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]3178<pre>
3179 switch &lt;intty&gt; &lt;value&gt;, label &lt;defaultdest&gt; [ &lt;intty&gt; &lt;val&gt;, label &lt;dest&gt; ... ]
3180</pre>
3181
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3182<h5>Overview:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]3183<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]3184 several different places. It is a generalization of the '<tt>br</tt>'
3185 instruction, allowing a branch to occur to one of many possible
3186 destinations.</p>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]3187
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3188<h5>Arguments:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]3189<p>The '<tt>switch</tt>' instruction uses three parameters: an integer
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3190 comparison value '<tt>value</tt>', a default '<tt>label</tt>' destination,
3191 and an array of pairs of comparison value constants and '<tt>label</tt>'s.
3192 The table is not allowed to contain duplicate constant entries.</p>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]3193
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3194<h5>Semantics:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3195<p>The <tt>switch</tt> instruction specifies a table of values and
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3196 destinations. When the '<tt>switch</tt>' instruction is executed, this table
3197 is searched for the given value. If the value is found, control flow is
Benjamin Kramer0f420382009-10-12 14:46:08 +0000[diff] [blame]3198 transferred to the corresponding destination; otherwise, control flow is
3199 transferred to the default destination.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3200
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]3201<h5>Implementation:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]3202<p>Depending on properties of the target machine and the particular
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3203 <tt>switch</tt> instruction, this instruction may be code generated in
3204 different ways. For example, it could be generated as a series of chained
3205 conditional branches or with a lookup table.</p>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]3206
3207<h5>Example:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]3208<pre>
3209 <i>; Emulate a conditional br instruction</i>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]3210 %Val = <a href="#i_zext">zext</a> i1 %value to i32
Dan Gohman623806e2009-01-04 23:44:43 +0000[diff] [blame]3211 switch i32 %Val, label %truedest [ i32 0, label %falsedest ]
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]3212
3213 <i>; Emulate an unconditional br instruction</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3214 switch i32 0, label %dest [ ]
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]3215
3216 <i>; Implement a jump table:</i>
Dan Gohman623806e2009-01-04 23:44:43 +0000[diff] [blame]3217 switch i32 %val, label %otherwise [ i32 0, label %onzero
3218 i32 1, label %onone
3219 i32 2, label %ontwo ]
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3220</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3221
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3222</div>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3223
Chris Lattner3ed871f2009-10-27 19:13:16 +0000[diff] [blame]3224
3225<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3226<h4>
Chris Lattnerd04cb6d2009-10-28 00:19:10 +0000[diff] [blame]3227 <a name="i_indirectbr">'<tt>indirectbr</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3228</h4>
Chris Lattner3ed871f2009-10-27 19:13:16 +0000[diff] [blame]3229
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3230<div>
Chris Lattner3ed871f2009-10-27 19:13:16 +0000[diff] [blame]3231
3232<h5>Syntax:</h5>
3233<pre>
Chris Lattnerd04cb6d2009-10-28 00:19:10 +0000[diff] [blame]3234 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]3235</pre>
3236
3237<h5>Overview:</h5>
3238
Chris Lattnerd04cb6d2009-10-28 00:19:10 +0000[diff] [blame]3239<p>The '<tt>indirectbr</tt>' instruction implements an indirect branch to a label
Chris Lattner3ed871f2009-10-27 19:13:16 +0000[diff] [blame]3240 within the current function, whose address is specified by
Chris Lattnere4801f72009-10-27 21:01:34 +0000[diff] [blame]3241 "<tt>address</tt>". Address must be derived from a <a
3242 href="#blockaddress">blockaddress</a> constant.</p>
Chris Lattner3ed871f2009-10-27 19:13:16 +0000[diff] [blame]3243
3244<h5>Arguments:</h5>
3245
3246<p>The '<tt>address</tt>' argument is the address of the label to jump to. The
3247 rest of the arguments indicate the full set of possible destinations that the
3248 address may point to. Blocks are allowed to occur multiple times in the
3249 destination list, though this isn't particularly useful.</p>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3250
Chris Lattner3ed871f2009-10-27 19:13:16 +0000[diff] [blame]3251<p>This destination list is required so that dataflow analysis has an accurate
3252 understanding of the CFG.</p>
3253
3254<h5>Semantics:</h5>
3255
3256<p>Control transfers to the block specified in the address argument. All
3257 possible destination blocks must be listed in the label list, otherwise this
3258 instruction has undefined behavior. This implies that jumps to labels
3259 defined in other functions have undefined behavior as well.</p>
3260
3261<h5>Implementation:</h5>
3262
3263<p>This is typically implemented with a jump through a register.</p>
3264
3265<h5>Example:</h5>
3266<pre>
Chris Lattnerd04cb6d2009-10-28 00:19:10 +0000[diff] [blame]3267 indirectbr i8* %Addr, [ label %bb1, label %bb2, label %bb3 ]
Chris Lattner3ed871f2009-10-27 19:13:16 +0000[diff] [blame]3268</pre>
3269
3270</div>
3271
3272
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3273<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3274<h4>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3275 <a name="i_invoke">'<tt>invoke</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3276</h4>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3277
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3278<div>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3279
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3280<h5>Syntax:</h5>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3281<pre>
Devang Patel02256232008-10-07 17:48:33 +0000[diff] [blame]3282 &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]3283 to label &lt;normal label&gt; unwind label &lt;exception label&gt;
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3284</pre>
3285
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]3286<h5>Overview:</h5>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3287<p>The '<tt>invoke</tt>' instruction causes control to transfer to a specified
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3288 function, with the possibility of control flow transfer to either the
3289 '<tt>normal</tt>' label or the '<tt>exception</tt>' label. If the callee
3290 function returns with the "<tt><a href="#i_ret">ret</a></tt>" instruction,
3291 control flow will return to the "normal" label. If the callee (or any
3292 indirect callees) returns with the "<a href="#i_unwind"><tt>unwind</tt></a>"
3293 instruction, control is interrupted and continued at the dynamically nearest
3294 "exception" label.</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3295
Bill Wendlingbbcb7cd2011-08-02 21:52:38 +0000[diff] [blame]3296<p>The '<tt>exception</tt>' label is a
3297 <i><a href="ExceptionHandling.html#overview">landing pad</a></i> for the
3298 exception. As such, '<tt>exception</tt>' label is required to have the
3299 "<a href="#i_landingpad"><tt>landingpad</tt></a>" instruction, which contains
3300 the information about about the behavior of the program after unwinding
3301 happens, as its first non-PHI instruction. The restrictions on the
3302 "<tt>landingpad</tt>" instruction's tightly couples it to the
3303 "<tt>invoke</tt>" instruction, so that the important information contained
3304 within the "<tt>landingpad</tt>" instruction can't be lost through normal
3305 code motion.</p>
3306
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3307<h5>Arguments:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3308<p>This instruction requires several arguments:</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3309
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3310<ol>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3311 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
3312 convention</a> the call should use. If none is specified, the call
3313 defaults to using C calling conventions.</li>
Devang Patel7e9b05e2008-10-06 18:50:38 +0000[diff] [blame]3314
3315 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3316 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
3317 '<tt>inreg</tt>' attributes are valid here.</li>
Devang Patel7e9b05e2008-10-06 18:50:38 +0000[diff] [blame]3318
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3319 <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]3320 function value being invoked. In most cases, this is a direct function
3321 invocation, but indirect <tt>invoke</tt>s are just as possible, branching
3322 off an arbitrary pointer to function value.</li>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3323
3324 <li>'<tt>function ptr val</tt>': An LLVM value containing a pointer to a
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3325 function to be invoked. </li>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3326
3327 <li>'<tt>function args</tt>': argument list whose types match the function
Chris Lattner47f2a832010-03-02 06:36:51 +0000[diff] [blame]3328 signature argument types and parameter attributes. All arguments must be
3329 of <a href="#t_firstclass">first class</a> type. If the function
3330 signature indicates the function accepts a variable number of arguments,
3331 the extra arguments can be specified.</li>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3332
3333 <li>'<tt>normal label</tt>': the label reached when the called function
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3334 executes a '<tt><a href="#i_ret">ret</a></tt>' instruction. </li>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3335
3336 <li>'<tt>exception label</tt>': the label reached when a callee returns with
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3337 the <a href="#i_unwind"><tt>unwind</tt></a> instruction. </li>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3338
Devang Patel02256232008-10-07 17:48:33 +0000[diff] [blame]3339 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3340 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
3341 '<tt>readnone</tt>' attributes are valid here.</li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3342</ol>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3343
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3344<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3345<p>This instruction is designed to operate as a standard
3346 '<tt><a href="#i_call">call</a></tt>' instruction in most regards. The
3347 primary difference is that it establishes an association with a label, which
3348 is used by the runtime library to unwind the stack.</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3349
3350<p>This instruction is used in languages with destructors to ensure that proper
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3351 cleanup is performed in the case of either a <tt>longjmp</tt> or a thrown
3352 exception. Additionally, this is important for implementation of
3353 '<tt>catch</tt>' clauses in high-level languages that support them.</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3354
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3355<p>For the purposes of the SSA form, the definition of the value returned by the
3356 '<tt>invoke</tt>' instruction is deemed to occur on the edge from the current
3357 block to the "normal" label. If the callee unwinds then no return value is
3358 available.</p>
Dan Gohman9069d892009-05-22 21:47:08 +0000[diff] [blame]3359
Chris Lattner97257f82010-01-15 18:08:37 +0000[diff] [blame]3360<p>Note that the code generator does not yet completely support unwind, and
3361that the invoke/unwind semantics are likely to change in future versions.</p>
3362
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3363<h5>Example:</h5>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3364<pre>
Nick Lewycky084ab472008-03-16 07:18:12 +0000[diff] [blame]3365 %retval = invoke i32 @Test(i32 15) to label %Continue
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]3366 unwind label %TestCleanup <i>; {i32}:retval set</i>
Nick Lewycky084ab472008-03-16 07:18:12 +0000[diff] [blame]3367 %retval = invoke <a href="#callingconv">coldcc</a> i32 %Testfnptr(i32 15) to label %Continue
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]3368 unwind label %TestCleanup <i>; {i32}:retval set</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3369</pre>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3370
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3371</div>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3372
Chris Lattner5ed60612003-09-03 00:41:47 +0000[diff] [blame]3373<!-- _______________________________________________________________________ -->
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3374
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3375<h4>
3376 <a name="i_unwind">'<tt>unwind</tt>' Instruction</a>
3377</h4>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3378
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3379<div>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3380
Chris Lattner5ed60612003-09-03 00:41:47 +0000[diff] [blame]3381<h5>Syntax:</h5>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3382<pre>
3383 unwind
3384</pre>
3385
Chris Lattner5ed60612003-09-03 00:41:47 +0000[diff] [blame]3386<h5>Overview:</h5>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3387<p>The '<tt>unwind</tt>' instruction unwinds the stack, continuing control flow
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3388 at the first callee in the dynamic call stack which used
3389 an <a href="#i_invoke"><tt>invoke</tt></a> instruction to perform the call.
3390 This is primarily used to implement exception handling.</p>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3391
Chris Lattner5ed60612003-09-03 00:41:47 +0000[diff] [blame]3392<h5>Semantics:</h5>
Chris Lattnerfe8519c2008-04-19 21:01:16 +0000[diff] [blame]3393<p>The '<tt>unwind</tt>' instruction causes execution of the current function to
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3394 immediately halt. The dynamic call stack is then searched for the
3395 first <a href="#i_invoke"><tt>invoke</tt></a> instruction on the call stack.
3396 Once found, execution continues at the "exceptional" destination block
3397 specified by the <tt>invoke</tt> instruction. If there is no <tt>invoke</tt>
3398 instruction in the dynamic call chain, undefined behavior results.</p>
3399
Chris Lattner97257f82010-01-15 18:08:37 +0000[diff] [blame]3400<p>Note that the code generator does not yet completely support unwind, and
3401that the invoke/unwind semantics are likely to change in future versions.</p>
3402
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3403</div>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3404
Bill Wendlingf891bf82011-07-31 06:30:59 +0000[diff] [blame]3405 <!-- _______________________________________________________________________ -->
3406
3407<h4>
3408 <a name="i_resume">'<tt>resume</tt>' Instruction</a>
3409</h4>
3410
3411<div>
3412
3413<h5>Syntax:</h5>
3414<pre>
3415 resume &lt;type&gt; &lt;value&gt;
3416</pre>
3417
3418<h5>Overview:</h5>
3419<p>The '<tt>resume</tt>' instruction is a terminator instruction that has no
3420 successors.</p>
3421
3422<h5>Arguments:</h5>
Bill Wendlingbbcb7cd2011-08-02 21:52:38 +0000[diff] [blame]3423<p>The '<tt>resume</tt>' instruction requires one argument, which must have the
Bill Wendlingc5a13612011-08-03 18:37:32 +0000[diff] [blame]3424 same type as the result of any '<tt>landingpad</tt>' instruction in the same
3425 function.</p>
Bill Wendlingf891bf82011-07-31 06:30:59 +0000[diff] [blame]3426
3427<h5>Semantics:</h5>
3428<p>The '<tt>resume</tt>' instruction resumes propagation of an existing
3429 (in-flight) exception whose unwinding was interrupted with
Bill Wendlingbbcb7cd2011-08-02 21:52:38 +0000[diff] [blame]3430 a <a href="#i_landingpad"><tt>landingpad</tt></a> instruction.</p>
Bill Wendlingf891bf82011-07-31 06:30:59 +0000[diff] [blame]3431
3432<h5>Example:</h5>
3433<pre>
Bill Wendlingbbcb7cd2011-08-02 21:52:38 +0000[diff] [blame]3434 resume { i8*, i32 } %exn
Bill Wendlingf891bf82011-07-31 06:30:59 +0000[diff] [blame]3435</pre>
3436
3437</div>
3438
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3439<!-- _______________________________________________________________________ -->
3440
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3441<h4>
3442 <a name="i_unreachable">'<tt>unreachable</tt>' Instruction</a>
3443</h4>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3444
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3445<div>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3446
3447<h5>Syntax:</h5>
3448<pre>
3449 unreachable
3450</pre>
3451
3452<h5>Overview:</h5>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3453<p>The '<tt>unreachable</tt>' instruction has no defined semantics. This
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3454 instruction is used to inform the optimizer that a particular portion of the
3455 code is not reachable. This can be used to indicate that the code after a
3456 no-return function cannot be reached, and other facts.</p>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3457
3458<h5>Semantics:</h5>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3459<p>The '<tt>unreachable</tt>' instruction has no defined semantics.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3460
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3461</div>
3462
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3463</div>
3464
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3465<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3466<h3>
3467 <a name="binaryops">Binary Operations</a>
3468</h3>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3469
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3470<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3471
3472<p>Binary operators are used to do most of the computation in a program. They
3473 require two operands of the same type, execute an operation on them, and
3474 produce a single value. The operands might represent multiple data, as is
3475 the case with the <a href="#t_vector">vector</a> data type. The result value
3476 has the same type as its operands.</p>
3477
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3478<p>There are several different binary operators:</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3479
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3480<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3481<h4>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3482 <a name="i_add">'<tt>add</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3483</h4>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3484
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3485<div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3486
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3487<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3488<pre>
Dan Gohmanb07de442009-07-20 22:41:19 +0000[diff] [blame]3489 &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]3490 &lt;result&gt; = add nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3491 &lt;result&gt; = add nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3492 &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]3493</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3494
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3495<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3496<p>The '<tt>add</tt>' instruction returns the sum of its two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3497
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3498<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3499<p>The two arguments to the '<tt>add</tt>' instruction must
3500 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3501 integer values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3502
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3503<h5>Semantics:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3504<p>The value produced is the integer sum of the two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3505
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3506<p>If the sum has unsigned overflow, the result returned is the mathematical
3507 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]3508
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3509<p>Because LLVM integers use a two's complement representation, this instruction
3510 is appropriate for both signed and unsigned integers.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3511
Dan Gohman902dfff2009-07-22 22:44:56 +0000[diff] [blame]3512<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3513 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3514 <tt>nsw</tt> keywords are present, the result value of the <tt>add</tt>
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]3515 is a <a href="#trapvalues">trap value</a> if unsigned and/or signed overflow,
3516 respectively, occurs.</p>
Dan Gohmanb07de442009-07-20 22:41:19 +0000[diff] [blame]3517
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3518<h5>Example:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3519<pre>
3520 &lt;result&gt; = add i32 4, %var <i>; yields {i32}:result = 4 + %var</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3521</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3522
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3523</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3524
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3525<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3526<h4>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3527 <a name="i_fadd">'<tt>fadd</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3528</h4>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3529
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3530<div>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3531
3532<h5>Syntax:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3533<pre>
3534 &lt;result&gt; = fadd &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3535</pre>
3536
3537<h5>Overview:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3538<p>The '<tt>fadd</tt>' instruction returns the sum of its two operands.</p>
3539
3540<h5>Arguments:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3541<p>The two arguments to the '<tt>fadd</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3542 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3543 floating point values. Both arguments must have identical types.</p>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3544
3545<h5>Semantics:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3546<p>The value produced is the floating point sum of the two operands.</p>
3547
3548<h5>Example:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3549<pre>
3550 &lt;result&gt; = fadd float 4.0, %var <i>; yields {float}:result = 4.0 + %var</i>
3551</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3552
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3553</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3554
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3555<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3556<h4>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3557 <a name="i_sub">'<tt>sub</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3558</h4>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3559
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3560<div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3561
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3562<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3563<pre>
Dan Gohman902dfff2009-07-22 22:44:56 +0000[diff] [blame]3564 &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]3565 &lt;result&gt; = sub nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3566 &lt;result&gt; = sub nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3567 &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]3568</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3569
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3570<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3571<p>The '<tt>sub</tt>' instruction returns the difference of its two
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3572 operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3573
3574<p>Note that the '<tt>sub</tt>' instruction is used to represent the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3575 '<tt>neg</tt>' instruction present in most other intermediate
3576 representations.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3577
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3578<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3579<p>The two arguments to the '<tt>sub</tt>' instruction must
3580 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3581 integer values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3582
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3583<h5>Semantics:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3584<p>The value produced is the integer difference of the two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3585
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3586<p>If the difference has unsigned overflow, the result returned is the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3587 mathematical result modulo 2<sup>n</sup>, where n is the bit width of the
3588 result.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3589
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3590<p>Because LLVM integers use a two's complement representation, this instruction
3591 is appropriate for both signed and unsigned integers.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3592
Dan Gohman902dfff2009-07-22 22:44:56 +0000[diff] [blame]3593<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3594 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3595 <tt>nsw</tt> keywords are present, the result value of the <tt>sub</tt>
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]3596 is a <a href="#trapvalues">trap value</a> if unsigned and/or signed overflow,
3597 respectively, occurs.</p>
Dan Gohmanb07de442009-07-20 22:41:19 +0000[diff] [blame]3598
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3599<h5>Example:</h5>
Bill Wendling2d8b9a82007-05-29 09:42:13 +0000[diff] [blame]3600<pre>
3601 &lt;result&gt; = sub i32 4, %var <i>; yields {i32}:result = 4 - %var</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3602 &lt;result&gt; = sub i32 0, %val <i>; yields {i32}:result = -%var</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3603</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3604
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3605</div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3606
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3607<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3608<h4>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3609 <a name="i_fsub">'<tt>fsub</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3610</h4>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3611
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3612<div>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3613
3614<h5>Syntax:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3615<pre>
3616 &lt;result&gt; = fsub &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3617</pre>
3618
3619<h5>Overview:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3620<p>The '<tt>fsub</tt>' instruction returns the difference of its two
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3621 operands.</p>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3622
3623<p>Note that the '<tt>fsub</tt>' instruction is used to represent the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3624 '<tt>fneg</tt>' instruction present in most other intermediate
3625 representations.</p>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3626
3627<h5>Arguments:</h5>
Bill Wendling972b7202009-07-20 02:32:41 +0000[diff] [blame]3628<p>The two arguments to the '<tt>fsub</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3629 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3630 floating point values. Both arguments must have identical types.</p>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3631
3632<h5>Semantics:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3633<p>The value produced is the floating point difference of the two operands.</p>
3634
3635<h5>Example:</h5>
3636<pre>
3637 &lt;result&gt; = fsub float 4.0, %var <i>; yields {float}:result = 4.0 - %var</i>
3638 &lt;result&gt; = fsub float -0.0, %val <i>; yields {float}:result = -%var</i>
3639</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3640
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3641</div>
3642
3643<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3644<h4>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3645 <a name="i_mul">'<tt>mul</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3646</h4>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3647
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3648<div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3649
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3650<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3651<pre>
Dan Gohman902dfff2009-07-22 22:44:56 +0000[diff] [blame]3652 &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]3653 &lt;result&gt; = mul nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3654 &lt;result&gt; = mul nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3655 &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]3656</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3657
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3658<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3659<p>The '<tt>mul</tt>' instruction returns the product of its two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3660
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3661<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3662<p>The two arguments to the '<tt>mul</tt>' instruction must
3663 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3664 integer values. Both arguments must have identical types.</p>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3665
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3666<h5>Semantics:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3667<p>The value produced is the integer product of the two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3668
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3669<p>If the result of the multiplication has unsigned overflow, the result
3670 returned is the mathematical result modulo 2<sup>n</sup>, where n is the bit
3671 width of the result.</p>
3672
3673<p>Because LLVM integers use a two's complement representation, and the result
3674 is the same width as the operands, this instruction returns the correct
3675 result for both signed and unsigned integers. If a full product
3676 (e.g. <tt>i32</tt>x<tt>i32</tt>-><tt>i64</tt>) is needed, the operands should
3677 be sign-extended or zero-extended as appropriate to the width of the full
3678 product.</p>
3679
Dan Gohman902dfff2009-07-22 22:44:56 +0000[diff] [blame]3680<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3681 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3682 <tt>nsw</tt> keywords are present, the result value of the <tt>mul</tt>
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]3683 is a <a href="#trapvalues">trap value</a> if unsigned and/or signed overflow,
3684 respectively, occurs.</p>
Dan Gohmanb07de442009-07-20 22:41:19 +0000[diff] [blame]3685
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3686<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3687<pre>
3688 &lt;result&gt; = mul i32 4, %var <i>; yields {i32}:result = 4 * %var</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3689</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3690
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3691</div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3692
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3693<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3694<h4>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3695 <a name="i_fmul">'<tt>fmul</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3696</h4>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3697
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3698<div>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3699
3700<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3701<pre>
3702 &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]3703</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3704
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3705<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3706<p>The '<tt>fmul</tt>' instruction returns the product of its two operands.</p>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3707
3708<h5>Arguments:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3709<p>The two arguments to the '<tt>fmul</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3710 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3711 floating point values. Both arguments must have identical types.</p>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3712
3713<h5>Semantics:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3714<p>The value produced is the floating point product of the two operands.</p>
3715
3716<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3717<pre>
3718 &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]3719</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3720
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3721</div>
3722
3723<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3724<h4>
3725 <a name="i_udiv">'<tt>udiv</tt>' Instruction</a>
3726</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3727
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3728<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3729
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3730<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3731<pre>
Chris Lattner35315d02011-02-06 21:44:57 +0000[diff] [blame]3732 &lt;result&gt; = udiv &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3733 &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]3734</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3735
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3736<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3737<p>The '<tt>udiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3738
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3739<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3740<p>The two arguments to the '<tt>udiv</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3741 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3742 values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3743
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3744<h5>Semantics:</h5>
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3745<p>The value produced is the unsigned integer quotient of the two operands.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3746
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3747<p>Note that unsigned integer division and signed integer division are distinct
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3748 operations; for signed integer division, use '<tt>sdiv</tt>'.</p>
3749
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3750<p>Division by zero leads to undefined behavior.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3751
Chris Lattner35315d02011-02-06 21:44:57 +0000[diff] [blame]3752<p>If the <tt>exact</tt> keyword is present, the result value of the
3753 <tt>udiv</tt> is a <a href="#trapvalues">trap value</a> if %op1 is not a
3754 multiple of %op2 (as such, "((a udiv exact b) mul b) == a").</p>
3755
3756
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3757<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3758<pre>
3759 &lt;result&gt; = udiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3760</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3761
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3762</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3763
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3764<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3765<h4>
3766 <a name="i_sdiv">'<tt>sdiv</tt>' Instruction</a>
3767</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3768
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3769<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3770
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3771<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3772<pre>
Dan Gohmanb07de442009-07-20 22:41:19 +0000[diff] [blame]3773 &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]3774 &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]3775</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3776
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3777<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3778<p>The '<tt>sdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3779
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3780<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3781<p>The two arguments to the '<tt>sdiv</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3782 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3783 values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3784
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3785<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3786<p>The value produced is the signed integer quotient of the two operands rounded
3787 towards zero.</p>
3788
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3789<p>Note that signed integer division and unsigned integer division are distinct
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3790 operations; for unsigned integer division, use '<tt>udiv</tt>'.</p>
3791
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3792<p>Division by zero leads to undefined behavior. Overflow also leads to
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3793 undefined behavior; this is a rare case, but can occur, for example, by doing
3794 a 32-bit division of -2147483648 by -1.</p>
3795
Dan Gohman71dfd782009-07-22 00:04:19 +0000[diff] [blame]3796<p>If the <tt>exact</tt> keyword is present, the result value of the
Dan Gohman57255802010-04-23 15:23:32 +0000[diff] [blame]3797 <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]3798 be rounded.</p>
Dan Gohmanb07de442009-07-20 22:41:19 +0000[diff] [blame]3799
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3800<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3801<pre>
3802 &lt;result&gt; = sdiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3803</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3804
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3805</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3806
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3807<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3808<h4>
3809 <a name="i_fdiv">'<tt>fdiv</tt>' Instruction</a>
3810</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3811
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3812<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3813
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3814<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3815<pre>
Gabor Greif0f75ad02008-08-07 21:46:00 +0000[diff] [blame]3816 &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]3817</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3818
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3819<h5>Overview:</h5>
3820<p>The '<tt>fdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3821
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3822<h5>Arguments:</h5>
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]3823<p>The two arguments to the '<tt>fdiv</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3824 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3825 floating point values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3826
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3827<h5>Semantics:</h5>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3828<p>The value produced is the floating point quotient of the two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3829
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3830<h5>Example:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3831<pre>
3832 &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]3833</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3834
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3835</div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3836
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3837<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3838<h4>
3839 <a name="i_urem">'<tt>urem</tt>' Instruction</a>
3840</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3841
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3842<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3843
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3844<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3845<pre>
3846 &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]3847</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3848
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3849<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3850<p>The '<tt>urem</tt>' instruction returns the remainder from the unsigned
3851 division of its two arguments.</p>
3852
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3853<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3854<p>The two arguments to the '<tt>urem</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3855 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3856 values. Both arguments must have identical types.</p>
3857
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3858<h5>Semantics:</h5>
3859<p>This instruction returns the unsigned integer <i>remainder</i> of a division.
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3860 This instruction always performs an unsigned division to get the
3861 remainder.</p>
3862
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3863<p>Note that unsigned integer remainder and signed integer remainder are
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3864 distinct operations; for signed integer remainder, use '<tt>srem</tt>'.</p>
3865
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3866<p>Taking the remainder of a division by zero leads to undefined behavior.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3867
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3868<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3869<pre>
3870 &lt;result&gt; = urem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3871</pre>
3872
3873</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3874
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3875<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3876<h4>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3877 <a name="i_srem">'<tt>srem</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3878</h4>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3879
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3880<div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3881
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3882<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3883<pre>
Gabor Greif0f75ad02008-08-07 21:46:00 +0000[diff] [blame]3884 &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]3885</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3886
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3887<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3888<p>The '<tt>srem</tt>' instruction returns the remainder from the signed
3889 division of its two operands. This instruction can also take
3890 <a href="#t_vector">vector</a> versions of the values in which case the
3891 elements must be integers.</p>
Chris Lattnerb8f816e2008-01-04 04:33:49 +0000[diff] [blame]3892
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3893<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3894<p>The two arguments to the '<tt>srem</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3895 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3896 values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3897
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3898<h5>Semantics:</h5>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3899<p>This instruction returns the <i>remainder</i> of a division (where the result
Duncan Sands2769c6e2011-03-07 09:12:24 +0000[diff] [blame]3900 is either zero or has the same sign as the dividend, <tt>op1</tt>), not the
3901 <i>modulo</i> operator (where the result is either zero or has the same sign
3902 as the divisor, <tt>op2</tt>) of a value.
3903 For more information about the difference,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3904 see <a href="http://mathforum.org/dr.math/problems/anne.4.28.99.html">The
3905 Math Forum</a>. For a table of how this is implemented in various languages,
3906 please see <a href="http://en.wikipedia.org/wiki/Modulo_operation">
3907 Wikipedia: modulo operation</a>.</p>
3908
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3909<p>Note that signed integer remainder and unsigned integer remainder are
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3910 distinct operations; for unsigned integer remainder, use '<tt>urem</tt>'.</p>
3911
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3912<p>Taking the remainder of a division by zero leads to undefined behavior.
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3913 Overflow also leads to undefined behavior; this is a rare case, but can
3914 occur, for example, by taking the remainder of a 32-bit division of
3915 -2147483648 by -1. (The remainder doesn't actually overflow, but this rule
3916 lets srem be implemented using instructions that return both the result of
3917 the division and the remainder.)</p>
3918
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3919<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3920<pre>
3921 &lt;result&gt; = srem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3922</pre>
3923
3924</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3925
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3926<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3927<h4>
3928 <a name="i_frem">'<tt>frem</tt>' Instruction</a>
3929</h4>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3930
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3931<div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3932
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3933<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3934<pre>
3935 &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]3936</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3937
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3938<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3939<p>The '<tt>frem</tt>' instruction returns the remainder from the division of
3940 its two operands.</p>
3941
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3942<h5>Arguments:</h5>
3943<p>The two arguments to the '<tt>frem</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3944 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3945 floating point values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3946
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3947<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3948<p>This instruction returns the <i>remainder</i> of a division. The remainder
3949 has the same sign as the dividend.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3950
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3951<h5>Example:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3952<pre>
3953 &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]3954</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3955
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3956</div>
Robert Bocchino820bc75b2006-02-17 21:18:08 +0000[diff] [blame]3957
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3958</div>
3959
Reid Spencer2ab01932007-02-02 13:57:07 +0000[diff] [blame]3960<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3961<h3>
3962 <a name="bitwiseops">Bitwise Binary Operations</a>
3963</h3>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3964
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3965<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3966
3967<p>Bitwise binary operators are used to do various forms of bit-twiddling in a
3968 program. They are generally very efficient instructions and can commonly be
3969 strength reduced from other instructions. They require two operands of the
3970 same type, execute an operation on them, and produce a single value. The
3971 resulting value is the same type as its operands.</p>
3972
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3973<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3974<h4>
3975 <a name="i_shl">'<tt>shl</tt>' Instruction</a>
3976</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3977
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3978<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3979
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3980<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3981<pre>
Chris Lattnera676c0f2011-02-07 16:40:21 +0000[diff] [blame]3982 &lt;result&gt; = shl &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3983 &lt;result&gt; = shl nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3984 &lt;result&gt; = shl nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3985 &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]3986</pre>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]3987
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3988<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3989<p>The '<tt>shl</tt>' instruction returns the first operand shifted to the left
3990 a specified number of bits.</p>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]3991
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3992<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3993<p>Both arguments to the '<tt>shl</tt>' instruction must be the
3994 same <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3995 integer type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3996
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3997<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3998<p>The value produced is <tt>op1</tt> * 2<sup><tt>op2</tt></sup> mod
3999 2<sup>n</sup>, where <tt>n</tt> is the width of the result. If <tt>op2</tt>
4000 is (statically or dynamically) negative or equal to or larger than the number
4001 of bits in <tt>op1</tt>, the result is undefined. If the arguments are
4002 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
4003 shift amount in <tt>op2</tt>.</p>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]4004
Chris Lattnera676c0f2011-02-07 16:40:21 +0000[diff] [blame]4005<p>If the <tt>nuw</tt> keyword is present, then the shift produces a
4006 <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]4007 the <tt>nsw</tt> keyword is present, then the shift produces a
Chris Lattnera676c0f2011-02-07 16:40:21 +0000[diff] [blame]4008 <a href="#trapvalues">trap value</a> if it shifts out any bits that disagree
4009 with the resultant sign bit. As such, NUW/NSW have the same semantics as
4010 they would if the shift were expressed as a mul instruction with the same
4011 nsw/nuw bits in (mul %op1, (shl 1, %op2)).</p>
4012
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4013<h5>Example:</h5>
4014<pre>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4015 &lt;result&gt; = shl i32 4, %var <i>; yields {i32}: 4 &lt;&lt; %var</i>
4016 &lt;result&gt; = shl i32 4, 2 <i>; yields {i32}: 16</i>
4017 &lt;result&gt; = shl i32 1, 10 <i>; yields {i32}: 1024</i>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]4018 &lt;result&gt; = shl i32 1, 32 <i>; undefined</i>
Mon P Wang4dd832d2008-12-09 05:46:39 +0000[diff] [blame]4019 &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]4020</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4021
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4022</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4023
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4024<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4025<h4>
4026 <a name="i_lshr">'<tt>lshr</tt>' Instruction</a>
4027</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4028
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4029<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4030
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4031<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4032<pre>
Chris Lattnera676c0f2011-02-07 16:40:21 +0000[diff] [blame]4033 &lt;result&gt; = lshr &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
4034 &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]4035</pre>
4036
4037<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4038<p>The '<tt>lshr</tt>' instruction (logical shift right) returns the first
4039 operand shifted to the right a specified number of bits with zero fill.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4040
4041<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4042<p>Both arguments to the '<tt>lshr</tt>' instruction must be the same
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4043 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
4044 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4045
4046<h5>Semantics:</h5>
4047<p>This instruction always performs a logical shift right operation. The most
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4048 significant bits of the result will be filled with zero bits after the shift.
4049 If <tt>op2</tt> is (statically or dynamically) equal to or larger than the
4050 number of bits in <tt>op1</tt>, the result is undefined. If the arguments are
4051 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
4052 shift amount in <tt>op2</tt>.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4053
Chris Lattnera676c0f2011-02-07 16:40:21 +0000[diff] [blame]4054<p>If the <tt>exact</tt> keyword is present, the result value of the
4055 <tt>lshr</tt> is a <a href="#trapvalues">trap value</a> if any of the bits
4056 shifted out are non-zero.</p>
4057
4058
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4059<h5>Example:</h5>
4060<pre>
4061 &lt;result&gt; = lshr i32 4, 1 <i>; yields {i32}:result = 2</i>
4062 &lt;result&gt; = lshr i32 4, 2 <i>; yields {i32}:result = 1</i>
4063 &lt;result&gt; = lshr i8 4, 3 <i>; yields {i8}:result = 0</i>
4064 &lt;result&gt; = lshr i8 -2, 1 <i>; yields {i8}:result = 0x7FFFFFFF </i>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]4065 &lt;result&gt; = lshr i32 1, 32 <i>; undefined</i>
Mon P Wang4dd832d2008-12-09 05:46:39 +0000[diff] [blame]4066 &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]4067</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4068
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4069</div>
4070
Reid Spencer2ab01932007-02-02 13:57:07 +0000[diff] [blame]4071<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4072<h4>
4073 <a name="i_ashr">'<tt>ashr</tt>' Instruction</a>
4074</h4>
4075
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4076<div>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4077
4078<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4079<pre>
Chris Lattnera676c0f2011-02-07 16:40:21 +0000[diff] [blame]4080 &lt;result&gt; = ashr &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
4081 &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]4082</pre>
4083
4084<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4085<p>The '<tt>ashr</tt>' instruction (arithmetic shift right) returns the first
4086 operand shifted to the right a specified number of bits with sign
4087 extension.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4088
4089<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4090<p>Both arguments to the '<tt>ashr</tt>' instruction must be the same
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4091 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
4092 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4093
4094<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4095<p>This instruction always performs an arithmetic shift right operation, The
4096 most significant bits of the result will be filled with the sign bit
4097 of <tt>op1</tt>. If <tt>op2</tt> is (statically or dynamically) equal to or
4098 larger than the number of bits in <tt>op1</tt>, the result is undefined. If
4099 the arguments are vectors, each vector element of <tt>op1</tt> is shifted by
4100 the corresponding shift amount in <tt>op2</tt>.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4101
Chris Lattnera676c0f2011-02-07 16:40:21 +0000[diff] [blame]4102<p>If the <tt>exact</tt> keyword is present, the result value of the
4103 <tt>ashr</tt> is a <a href="#trapvalues">trap value</a> if any of the bits
4104 shifted out are non-zero.</p>
4105
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4106<h5>Example:</h5>
4107<pre>
4108 &lt;result&gt; = ashr i32 4, 1 <i>; yields {i32}:result = 2</i>
4109 &lt;result&gt; = ashr i32 4, 2 <i>; yields {i32}:result = 1</i>
4110 &lt;result&gt; = ashr i8 4, 3 <i>; yields {i8}:result = 0</i>
4111 &lt;result&gt; = ashr i8 -2, 1 <i>; yields {i8}:result = -1</i>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]4112 &lt;result&gt; = ashr i32 1, 32 <i>; undefined</i>
Mon P Wang4dd832d2008-12-09 05:46:39 +0000[diff] [blame]4113 &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]4114</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4115
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4116</div>
4117
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4118<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4119<h4>
4120 <a name="i_and">'<tt>and</tt>' Instruction</a>
4121</h4>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4122
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4123<div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4124
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4125<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4126<pre>
Gabor Greif0f75ad02008-08-07 21:46:00 +0000[diff] [blame]4127 &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]4128</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4129
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4130<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4131<p>The '<tt>and</tt>' instruction returns the bitwise logical and of its two
4132 operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4133
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4134<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4135<p>The two arguments to the '<tt>and</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4136 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
4137 values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4138
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4139<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4140<p>The truth table used for the '<tt>and</tt>' instruction is:</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4141
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4142<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]4143 <tbody>
4144 <tr>
4145 <td>In0</td>
4146 <td>In1</td>
4147 <td>Out</td>
4148 </tr>
4149 <tr>
4150 <td>0</td>
4151 <td>0</td>
4152 <td>0</td>
4153 </tr>
4154 <tr>
4155 <td>0</td>
4156 <td>1</td>
4157 <td>0</td>
4158 </tr>
4159 <tr>
4160 <td>1</td>
4161 <td>0</td>
4162 <td>0</td>
4163 </tr>
4164 <tr>
4165 <td>1</td>
4166 <td>1</td>
4167 <td>1</td>
4168 </tr>
4169 </tbody>
4170</table>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4171
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4172<h5>Example:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4173<pre>
4174 &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]4175 &lt;result&gt; = and i32 15, 40 <i>; yields {i32}:result = 8</i>
4176 &lt;result&gt; = and i32 4, 8 <i>; yields {i32}:result = 0</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4177</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4178</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4179<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4180<h4>
4181 <a name="i_or">'<tt>or</tt>' Instruction</a>
4182</h4>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4183
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4184<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4185
4186<h5>Syntax:</h5>
4187<pre>
4188 &lt;result&gt; = or &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
4189</pre>
4190
4191<h5>Overview:</h5>
4192<p>The '<tt>or</tt>' instruction returns the bitwise logical inclusive or of its
4193 two operands.</p>
4194
4195<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4196<p>The two arguments to the '<tt>or</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4197 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
4198 values. Both arguments must have identical types.</p>
4199
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4200<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4201<p>The truth table used for the '<tt>or</tt>' instruction is:</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4202
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]4203<table border="1" cellspacing="0" cellpadding="4">
4204 <tbody>
4205 <tr>
4206 <td>In0</td>
4207 <td>In1</td>
4208 <td>Out</td>
4209 </tr>
4210 <tr>
4211 <td>0</td>
4212 <td>0</td>
4213 <td>0</td>
4214 </tr>
4215 <tr>
4216 <td>0</td>
4217 <td>1</td>
4218 <td>1</td>
4219 </tr>
4220 <tr>
4221 <td>1</td>
4222 <td>0</td>
4223 <td>1</td>
4224 </tr>
4225 <tr>
4226 <td>1</td>
4227 <td>1</td>
4228 <td>1</td>
4229 </tr>
4230 </tbody>
4231</table>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4232
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4233<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4234<pre>
4235 &lt;result&gt; = or i32 4, %var <i>; yields {i32}:result = 4 | %var</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4236 &lt;result&gt; = or i32 15, 40 <i>; yields {i32}:result = 47</i>
4237 &lt;result&gt; = or i32 4, 8 <i>; yields {i32}:result = 12</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4238</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4239
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4240</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4241
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4242<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4243<h4>
4244 <a name="i_xor">'<tt>xor</tt>' Instruction</a>
4245</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4246
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4247<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4248
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4249<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4250<pre>
4251 &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]4252</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4253
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4254<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4255<p>The '<tt>xor</tt>' instruction returns the bitwise logical exclusive or of
4256 its two operands. The <tt>xor</tt> is used to implement the "one's
4257 complement" operation, which is the "~" operator in C.</p>
4258
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4259<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4260<p>The two arguments to the '<tt>xor</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4261 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
4262 values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4263
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4264<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4265<p>The truth table used for the '<tt>xor</tt>' instruction is:</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4266
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]4267<table border="1" cellspacing="0" cellpadding="4">
4268 <tbody>
4269 <tr>
4270 <td>In0</td>
4271 <td>In1</td>
4272 <td>Out</td>
4273 </tr>
4274 <tr>
4275 <td>0</td>
4276 <td>0</td>
4277 <td>0</td>
4278 </tr>
4279 <tr>
4280 <td>0</td>
4281 <td>1</td>
4282 <td>1</td>
4283 </tr>
4284 <tr>
4285 <td>1</td>
4286 <td>0</td>
4287 <td>1</td>
4288 </tr>
4289 <tr>
4290 <td>1</td>
4291 <td>1</td>
4292 <td>0</td>
4293 </tr>
4294 </tbody>
4295</table>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4296
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4297<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4298<pre>
4299 &lt;result&gt; = xor i32 4, %var <i>; yields {i32}:result = 4 ^ %var</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4300 &lt;result&gt; = xor i32 15, 40 <i>; yields {i32}:result = 39</i>
4301 &lt;result&gt; = xor i32 4, 8 <i>; yields {i32}:result = 12</i>
4302 &lt;result&gt; = xor i32 %V, -1 <i>; yields {i32}:result = ~%V</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4303</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4304
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4305</div>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4306
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4307</div>
4308
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4309<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4310<h3>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4311 <a name="vectorops">Vector Operations</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4312</h3>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4313
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4314<div>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4315
4316<p>LLVM supports several instructions to represent vector operations in a
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4317 target-independent manner. These instructions cover the element-access and
4318 vector-specific operations needed to process vectors effectively. While LLVM
4319 does directly support these vector operations, many sophisticated algorithms
4320 will want to use target-specific intrinsics to take full advantage of a
4321 specific target.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4322
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4323<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4324<h4>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4325 <a name="i_extractelement">'<tt>extractelement</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4326</h4>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4327
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4328<div>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4329
4330<h5>Syntax:</h5>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4331<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4332 &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]4333</pre>
4334
4335<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4336<p>The '<tt>extractelement</tt>' instruction extracts a single scalar element
4337 from a vector at a specified index.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4338
4339
4340<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4341<p>The first operand of an '<tt>extractelement</tt>' instruction is a value
4342 of <a href="#t_vector">vector</a> type. The second operand is an index
4343 indicating the position from which to extract the element. The index may be
4344 a variable.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4345
4346<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4347<p>The result is a scalar of the same type as the element type of
4348 <tt>val</tt>. Its value is the value at position <tt>idx</tt> of
4349 <tt>val</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
4350 results are undefined.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4351
4352<h5>Example:</h5>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4353<pre>
Gabor Greif03ab4dc2009-10-28 13:14:50 +0000[diff] [blame]4354 &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]4355</pre>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4356
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4357</div>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4358
4359<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4360<h4>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4361 <a name="i_insertelement">'<tt>insertelement</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4362</h4>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4363
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4364<div>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4365
4366<h5>Syntax:</h5>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4367<pre>
Dan Gohman43ba0672008-05-12 23:38:42 +0000[diff] [blame]4368 &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]4369</pre>
4370
4371<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4372<p>The '<tt>insertelement</tt>' instruction inserts a scalar element into a
4373 vector at a specified index.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4374
4375<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4376<p>The first operand of an '<tt>insertelement</tt>' instruction is a value
4377 of <a href="#t_vector">vector</a> type. The second operand is a scalar value
4378 whose type must equal the element type of the first operand. The third
4379 operand is an index indicating the position at which to insert the value.
4380 The index may be a variable.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4381
4382<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4383<p>The result is a vector of the same type as <tt>val</tt>. Its element values
4384 are those of <tt>val</tt> except at position <tt>idx</tt>, where it gets the
4385 value <tt>elt</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
4386 results are undefined.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4387
4388<h5>Example:</h5>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4389<pre>
Gabor Greif03ab4dc2009-10-28 13:14:50 +0000[diff] [blame]4390 &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]4391</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4392
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4393</div>
4394
4395<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4396<h4>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4397 <a name="i_shufflevector">'<tt>shufflevector</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4398</h4>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4399
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4400<div>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4401
4402<h5>Syntax:</h5>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4403<pre>
Mon P Wang25f01062008-11-10 04:46:22 +0000[diff] [blame]4404 &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]4405</pre>
4406
4407<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4408<p>The '<tt>shufflevector</tt>' instruction constructs a permutation of elements
4409 from two input vectors, returning a vector with the same element type as the
4410 input and length that is the same as the shuffle mask.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4411
4412<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4413<p>The first two operands of a '<tt>shufflevector</tt>' instruction are vectors
4414 with types that match each other. The third argument is a shuffle mask whose
4415 element type is always 'i32'. The result of the instruction is a vector
4416 whose length is the same as the shuffle mask and whose element type is the
4417 same as the element type of the first two operands.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4418
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4419<p>The shuffle mask operand is required to be a constant vector with either
4420 constant integer or undef values.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4421
4422<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4423<p>The elements of the two input vectors are numbered from left to right across
4424 both of the vectors. The shuffle mask operand specifies, for each element of
4425 the result vector, which element of the two input vectors the result element
4426 gets. The element selector may be undef (meaning "don't care") and the
4427 second operand may be undef if performing a shuffle from only one vector.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4428
4429<h5>Example:</h5>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4430<pre>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4431 &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]4432 &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]4433 &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]4434 &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]4435 &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]4436 &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]4437 &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]4438 &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]4439</pre>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4440
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4441</div>
Tanya Lattnerb138bbe2006-04-14 19:24:33 +0000[diff] [blame]4442
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4443</div>
4444
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4445<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4446<h3>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4447 <a name="aggregateops">Aggregate Operations</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4448</h3>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4449
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4450<div>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4451
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]4452<p>LLVM supports several instructions for working with
4453 <a href="#t_aggregate">aggregate</a> values.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4454
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4455<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4456<h4>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4457 <a name="i_extractvalue">'<tt>extractvalue</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4458</h4>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4459
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4460<div>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4461
4462<h5>Syntax:</h5>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4463<pre>
4464 &lt;result&gt; = extractvalue &lt;aggregate type&gt; &lt;val&gt;, &lt;idx&gt;{, &lt;idx&gt;}*
4465</pre>
4466
4467<h5>Overview:</h5>
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]4468<p>The '<tt>extractvalue</tt>' instruction extracts the value of a member field
4469 from an <a href="#t_aggregate">aggregate</a> value.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4470
4471<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4472<p>The first operand of an '<tt>extractvalue</tt>' instruction is a value
Chris Lattner13ee7952010-08-28 04:09:24 +0000[diff] [blame]4473 of <a href="#t_struct">struct</a> or
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]4474 <a href="#t_array">array</a> type. The operands are constant indices to
4475 specify which value to extract in a similar manner as indices in a
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4476 '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
Frits van Bommel7cf63ac2010-12-05 20:54:38 +0000[diff] [blame]4477 <p>The major differences to <tt>getelementptr</tt> indexing are:</p>
4478 <ul>
4479 <li>Since the value being indexed is not a pointer, the first index is
4480 omitted and assumed to be zero.</li>
4481 <li>At least one index must be specified.</li>
4482 <li>Not only struct indices but also array indices must be in
4483 bounds.</li>
4484 </ul>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4485
4486<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4487<p>The result is the value at the position in the aggregate specified by the
4488 index operands.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4489
4490<h5>Example:</h5>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4491<pre>
Gabor Greif03ab4dc2009-10-28 13:14:50 +0000[diff] [blame]4492 &lt;result&gt; = extractvalue {i32, float} %agg, 0 <i>; yields i32</i>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4493</pre>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4494
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4495</div>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4496
4497<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4498<h4>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4499 <a name="i_insertvalue">'<tt>insertvalue</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4500</h4>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4501
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4502<div>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4503
4504<h5>Syntax:</h5>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4505<pre>
Bill Wendlingf6a91cf2011-07-26 20:42:28 +0000[diff] [blame]4506 &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]4507</pre>
4508
4509<h5>Overview:</h5>
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]4510<p>The '<tt>insertvalue</tt>' instruction inserts a value into a member field
4511 in an <a href="#t_aggregate">aggregate</a> value.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4512
4513<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4514<p>The first operand of an '<tt>insertvalue</tt>' instruction is a value
Chris Lattner13ee7952010-08-28 04:09:24 +0000[diff] [blame]4515 of <a href="#t_struct">struct</a> or
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]4516 <a href="#t_array">array</a> type. The second operand is a first-class
4517 value to insert. The following operands are constant indices indicating
4518 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]4519 '<tt><a href="#i_extractvalue">extractvalue</a></tt>' instruction. The
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4520 value to insert must have the same type as the value identified by the
4521 indices.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4522
4523<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4524<p>The result is an aggregate of the same type as <tt>val</tt>. Its value is
4525 that of <tt>val</tt> except that the value at the position specified by the
4526 indices is that of <tt>elt</tt>.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4527
4528<h5>Example:</h5>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4529<pre>
Chris Lattnerc2e85402011-05-22 07:18:08 +0000[diff] [blame]4530 %agg1 = insertvalue {i32, float} undef, i32 1, 0 <i>; yields {i32 1, float undef}</i>
4531 %agg2 = insertvalue {i32, float} %agg1, float %val, 1 <i>; yields {i32 1, float %val}</i>
4532 %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]4533</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4534
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4535</div>
4536
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4537</div>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4538
4539<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4540<h3>
Chris Lattner6ab66722006-08-15 00:45:58 +0000[diff] [blame]4541 <a name="memoryops">Memory Access and Addressing Operations</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4542</h3>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4543
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4544<div>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4545
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4546<p>A key design point of an SSA-based representation is how it represents
4547 memory. In LLVM, no memory locations are in SSA form, which makes things
Victor Hernandeza70c6df2009-10-26 23:44:29 +0000[diff] [blame]4548 very simple. This section describes how to read, write, and allocate
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4549 memory in LLVM.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4550
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4551<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4552<h4>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4553 <a name="i_alloca">'<tt>alloca</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4554</h4>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4555
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4556<div>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4557
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4558<h5>Syntax:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4559<pre>
Dan Gohman2140a742010-05-28 01:14:11 +0000[diff] [blame]4560 &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]4561</pre>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4562
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4563<h5>Overview:</h5>
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]4564<p>The '<tt>alloca</tt>' instruction allocates memory on the stack frame of the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4565 currently executing function, to be automatically released when this function
4566 returns to its caller. The object is always allocated in the generic address
4567 space (address space zero).</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4568
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4569<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4570<p>The '<tt>alloca</tt>' instruction
4571 allocates <tt>sizeof(&lt;type&gt;)*NumElements</tt> bytes of memory on the
4572 runtime stack, returning a pointer of the appropriate type to the program.
4573 If "NumElements" is specified, it is the number of elements allocated,
4574 otherwise "NumElements" is defaulted to be one. If a constant alignment is
4575 specified, the value result of the allocation is guaranteed to be aligned to
4576 at least that boundary. If not specified, or if zero, the target can choose
4577 to align the allocation on any convenient boundary compatible with the
4578 type.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4579
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4580<p>'<tt>type</tt>' may be any sized type.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4581
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4582<h5>Semantics:</h5>
Bill Wendling9ee6a312009-05-08 20:49:29 +0000[diff] [blame]4583<p>Memory is allocated; a pointer is returned. The operation is undefined if
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4584 there is insufficient stack space for the allocation. '<tt>alloca</tt>'d
4585 memory is automatically released when the function returns. The
4586 '<tt>alloca</tt>' instruction is commonly used to represent automatic
4587 variables that must have an address available. When the function returns
4588 (either with the <tt><a href="#i_ret">ret</a></tt>
4589 or <tt><a href="#i_unwind">unwind</a></tt> instructions), the memory is
4590 reclaimed. Allocating zero bytes is legal, but the result is undefined.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4591
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4592<h5>Example:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4593<pre>
Dan Gohman7a5acb52009-01-04 23:49:44 +0000[diff] [blame]4594 %ptr = alloca i32 <i>; yields {i32*}:ptr</i>
4595 %ptr = alloca i32, i32 4 <i>; yields {i32*}:ptr</i>
4596 %ptr = alloca i32, i32 4, align 1024 <i>; yields {i32*}:ptr</i>
4597 %ptr = alloca i32, align 1024 <i>; yields {i32*}:ptr</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4598</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4599
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4600</div>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4601
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4602<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4603<h4>
4604 <a name="i_load">'<tt>load</tt>' Instruction</a>
4605</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4606
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4607<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4608
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4609<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4610<pre>
Eli Friedman02e737b2011-08-12 22:50:01 +0000[diff] [blame]4611 &lt;result&gt; = load [volatile] &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;][, !nontemporal !&lt;index&gt;]
4612 &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]4613 !&lt;index&gt; = !{ i32 1 }
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4614</pre>
4615
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4616<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4617<p>The '<tt>load</tt>' instruction is used to read from memory.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4618
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4619<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4620<p>The argument to the '<tt>load</tt>' instruction specifies the memory address
4621 from which to load. The pointer must point to
4622 a <a href="#t_firstclass">first class</a> type. If the <tt>load</tt> is
4623 marked as <tt>volatile</tt>, then the optimizer is not allowed to modify the
Jeffrey Yasskin5d284ae2010-04-26 21:21:24 +0000[diff] [blame]4624 number or order of execution of this <tt>load</tt> with other <a
4625 href="#volatile">volatile operations</a>.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4626
Eli Friedman59b66882011-08-09 23:02:53 +0000[diff] [blame]4627<p>If the <code>load</code> is marked as <code>atomic</code>, it takes an extra
4628 <a href="#ordering">ordering</a> and optional <code>singlethread</code>
4629 argument. The <code>release</code> and <code>acq_rel</code> orderings are
4630 not valid on <code>load</code> instructions. Atomic loads produce <a
4631 href="#memorymodel">defined</a> results when they may see multiple atomic
4632 stores. The type of the pointee must be an integer type whose bit width
4633 is a power of two greater than or equal to eight and less than or equal
4634 to a target-specific size limit. <code>align</code> must be explicitly
4635 specified on atomic loads, and the load has undefined behavior if the
4636 alignment is not set to a value which is at least the size in bytes of
4637 the pointee. <code>!nontemporal</code> does not have any defined semantics
4638 for atomic loads.</p>
4639
Bill Wendlingbc4024f2010-02-25 21:23:24 +0000[diff] [blame]4640<p>The optional constant <tt>align</tt> argument specifies the alignment of the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4641 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]4642 omitted <tt>align</tt> argument means that the operation has the preferential
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4643 alignment for the target. It is the responsibility of the code emitter to
4644 ensure that the alignment information is correct. Overestimating the
Bill Wendlingbc4024f2010-02-25 21:23:24 +0000[diff] [blame]4645 alignment results in undefined behavior. Underestimating the alignment may
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4646 produce less efficient code. An alignment of 1 is always safe.</p>
4647
Bill Wendlingbc4024f2010-02-25 21:23:24 +0000[diff] [blame]4648<p>The optional <tt>!nontemporal</tt> metadata must reference a single
4649 metatadata name &lt;index&gt; corresponding to a metadata node with
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]4650 one <tt>i32</tt> entry of value 1. The existence of
Bill Wendlingbc4024f2010-02-25 21:23:24 +0000[diff] [blame]4651 the <tt>!nontemporal</tt> metatadata on the instruction tells the optimizer
4652 and code generator that this load is not expected to be reused in the cache.
4653 The code generator may select special instructions to save cache bandwidth,
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]4654 such as the <tt>MOVNT</tt> instruction on x86.</p>
David Greene9641d062010-02-16 20:50:18 +0000[diff] [blame]4655
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4656<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4657<p>The location of memory pointed to is loaded. If the value being loaded is of
4658 scalar type then the number of bytes read does not exceed the minimum number
4659 of bytes needed to hold all bits of the type. For example, loading an
4660 <tt>i24</tt> reads at most three bytes. When loading a value of a type like
4661 <tt>i20</tt> with a size that is not an integral number of bytes, the result
4662 is undefined if the value was not originally written using a store of the
4663 same type.</p>
4664
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4665<h5>Examples:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4666<pre>
4667 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
4668 <a href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4669 %val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4670</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4671
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4672</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4673
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4674<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4675<h4>
4676 <a name="i_store">'<tt>store</tt>' Instruction</a>
4677</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4678
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4679<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4680
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4681<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4682<pre>
Eli Friedman02e737b2011-08-12 22:50:01 +0000[diff] [blame]4683 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>
4684 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]4685</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4686
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4687<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4688<p>The '<tt>store</tt>' instruction is used to write to memory.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4689
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4690<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4691<p>There are two arguments to the '<tt>store</tt>' instruction: a value to store
4692 and an address at which to store it. The type of the
4693 '<tt>&lt;pointer&gt;</tt>' operand must be a pointer to
4694 the <a href="#t_firstclass">first class</a> type of the
Jeffrey Yasskin5d284ae2010-04-26 21:21:24 +0000[diff] [blame]4695 '<tt>&lt;value&gt;</tt>' operand. If the <tt>store</tt> is marked as
4696 <tt>volatile</tt>, then the optimizer is not allowed to modify the number or
4697 order of execution of this <tt>store</tt> with other <a
4698 href="#volatile">volatile operations</a>.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4699
Eli Friedman59b66882011-08-09 23:02:53 +0000[diff] [blame]4700<p>If the <code>store</code> is marked as <code>atomic</code>, it takes an extra
4701 <a href="#ordering">ordering</a> and optional <code>singlethread</code>
4702 argument. The <code>acquire</code> and <code>acq_rel</code> orderings aren't
4703 valid on <code>store</code> instructions. Atomic loads produce <a
4704 href="#memorymodel">defined</a> results when they may see multiple atomic
4705 stores. The type of the pointee must be an integer type whose bit width
4706 is a power of two greater than or equal to eight and less than or equal
4707 to a target-specific size limit. <code>align</code> must be explicitly
4708 specified on atomic stores, and the store has undefined behavior if the
4709 alignment is not set to a value which is at least the size in bytes of
4710 the pointee. <code>!nontemporal</code> does not have any defined semantics
4711 for atomic stores.</p>
4712
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4713<p>The optional constant "align" argument specifies the alignment of the
4714 operation (that is, the alignment of the memory address). A value of 0 or an
4715 omitted "align" argument means that the operation has the preferential
4716 alignment for the target. It is the responsibility of the code emitter to
4717 ensure that the alignment information is correct. Overestimating the
4718 alignment results in an undefined behavior. Underestimating the alignment may
4719 produce less efficient code. An alignment of 1 is always safe.</p>
4720
David Greene9641d062010-02-16 20:50:18 +0000[diff] [blame]4721<p>The optional !nontemporal metadata must reference a single metatadata
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]4722 name &lt;index&gt; corresponding to a metadata node with one i32 entry of
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]4723 value 1. The existence of the !nontemporal metatadata on the
David Greene9641d062010-02-16 20:50:18 +0000[diff] [blame]4724 instruction tells the optimizer and code generator that this load is
4725 not expected to be reused in the cache. The code generator may
4726 select special instructions to save cache bandwidth, such as the
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]4727 MOVNT instruction on x86.</p>
David Greene9641d062010-02-16 20:50:18 +0000[diff] [blame]4728
4729
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]4730<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4731<p>The contents of memory are updated to contain '<tt>&lt;value&gt;</tt>' at the
4732 location specified by the '<tt>&lt;pointer&gt;</tt>' operand. If
4733 '<tt>&lt;value&gt;</tt>' is of scalar type then the number of bytes written
4734 does not exceed the minimum number of bytes needed to hold all bits of the
4735 type. For example, storing an <tt>i24</tt> writes at most three bytes. When
4736 writing a value of a type like <tt>i20</tt> with a size that is not an
4737 integral number of bytes, it is unspecified what happens to the extra bits
4738 that do not belong to the type, but they will typically be overwritten.</p>
4739
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4740<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4741<pre>
4742 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Bill Wendling8830ffe2007-10-22 05:10:05 +0000[diff] [blame]4743 store i32 3, i32* %ptr <i>; yields {void}</i>
4744 %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]4745</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4746
Reid Spencer443460a2006-11-09 21:15:49 +0000[diff] [blame]4747</div>
4748
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4749<!-- _______________________________________________________________________ -->
NAKAMURA Takumi0300d882011-08-12 06:17:17 +0000[diff] [blame]4750<h4>
4751<a name="i_fence">'<tt>fence</tt>' Instruction</a>
4752</h4>
Eli Friedmanfee02c62011-07-25 23:16:38 +0000[diff] [blame]4753
NAKAMURA Takumi0300d882011-08-12 06:17:17 +0000[diff] [blame]4754<div>
Eli Friedmanfee02c62011-07-25 23:16:38 +0000[diff] [blame]4755
4756<h5>Syntax:</h5>
4757<pre>
4758 fence [singlethread] &lt;ordering&gt; <i>; yields {void}</i>
4759</pre>
4760
4761<h5>Overview:</h5>
4762<p>The '<tt>fence</tt>' instruction is used to introduce happens-before edges
4763between operations.</p>
4764
4765<h5>Arguments:</h5> <p>'<code>fence</code>' instructions take an <a
4766href="#ordering">ordering</a> argument which defines what
4767<i>synchronizes-with</i> edges they add. They can only be given
4768<code>acquire</code>, <code>release</code>, <code>acq_rel</code>, and
4769<code>seq_cst</code> orderings.</p>
4770
4771<h5>Semantics:</h5>
4772<p>A fence <var>A</var> which has (at least) <code>release</code> ordering
4773semantics <i>synchronizes with</i> a fence <var>B</var> with (at least)
4774<code>acquire</code> ordering semantics if and only if there exist atomic
4775operations <var>X</var> and <var>Y</var>, both operating on some atomic object
4776<var>M</var>, such that <var>A</var> is sequenced before <var>X</var>,
4777<var>X</var> modifies <var>M</var> (either directly or through some side effect
4778of a sequence headed by <var>X</var>), <var>Y</var> is sequenced before
4779<var>B</var>, and <var>Y</var> observes <var>M</var>. This provides a
4780<i>happens-before</i> dependency between <var>A</var> and <var>B</var>. Rather
4781than an explicit <code>fence</code>, one (but not both) of the atomic operations
4782<var>X</var> or <var>Y</var> might provide a <code>release</code> or
4783<code>acquire</code> (resp.) ordering constraint and still
4784<i>synchronize-with</i> the explicit <code>fence</code> and establish the
4785<i>happens-before</i> edge.</p>
4786
4787<p>A <code>fence</code> which has <code>seq_cst</code> ordering, in addition to
4788having both <code>acquire</code> and <code>release</code> semantics specified
4789above, participates in the global program order of other <code>seq_cst</code>
4790operations and/or fences.</p>
4791
4792<p>The optional "<a href="#singlethread"><code>singlethread</code></a>" argument
4793specifies that the fence only synchronizes with other fences in the same
4794thread. (This is useful for interacting with signal handlers.)</p>
4795
Eli Friedmanfee02c62011-07-25 23:16:38 +0000[diff] [blame]4796<h5>Example:</h5>
4797<pre>
4798 fence acquire <i>; yields {void}</i>
4799 fence singlethread seq_cst <i>; yields {void}</i>
4800</pre>
4801
4802</div>
4803
4804<!-- _______________________________________________________________________ -->
NAKAMURA Takumi0300d882011-08-12 06:17:17 +0000[diff] [blame]4805<h4>
4806<a name="i_cmpxchg">'<tt>cmpxchg</tt>' Instruction</a>
4807</h4>
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]4808
NAKAMURA Takumi0300d882011-08-12 06:17:17 +0000[diff] [blame]4809<div>
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]4810
4811<h5>Syntax:</h5>
4812<pre>
Eli Friedman02e737b2011-08-12 22:50:01 +0000[diff] [blame]4813 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]4814</pre>
4815
4816<h5>Overview:</h5>
4817<p>The '<tt>cmpxchg</tt>' instruction is used to atomically modify memory.
4818It loads a value in memory and compares it to a given value. If they are
4819equal, it stores a new value into the memory.</p>
4820
4821<h5>Arguments:</h5>
4822<p>There are three arguments to the '<code>cmpxchg</code>' instruction: an
4823address to operate on, a value to compare to the value currently be at that
4824address, and a new value to place at that address if the compared values are
4825equal. The type of '<var>&lt;cmp&gt;</var>' must be an integer type whose
4826bit width is a power of two greater than or equal to eight and less than
4827or equal to a target-specific size limit. '<var>&lt;cmp&gt;</var>' and
4828'<var>&lt;new&gt;</var>' must have the same type, and the type of
4829'<var>&lt;pointer&gt;</var>' must be a pointer to that type. If the
4830<code>cmpxchg</code> is marked as <code>volatile</code>, then the
4831optimizer is not allowed to modify the number or order of execution
4832of this <code>cmpxchg</code> with other <a href="#volatile">volatile
4833operations</a>.</p>
4834
4835<!-- FIXME: Extend allowed types. -->
4836
4837<p>The <a href="#ordering"><var>ordering</var></a> argument specifies how this
4838<code>cmpxchg</code> synchronizes with other atomic operations.</p>
4839
4840<p>The optional "<code>singlethread</code>" argument declares that the
4841<code>cmpxchg</code> is only atomic with respect to code (usually signal
4842handlers) running in the same thread as the <code>cmpxchg</code>. Otherwise the
4843cmpxchg is atomic with respect to all other code in the system.</p>
4844
4845<p>The pointer passed into cmpxchg must have alignment greater than or equal to
4846the size in memory of the operand.
4847
4848<h5>Semantics:</h5>
4849<p>The contents of memory at the location specified by the
4850'<tt>&lt;pointer&gt;</tt>' operand is read and compared to
4851'<tt>&lt;cmp&gt;</tt>'; if the read value is the equal,
4852'<tt>&lt;new&gt;</tt>' is written. The original value at the location
4853is returned.
4854
4855<p>A successful <code>cmpxchg</code> is a read-modify-write instruction for the
4856purpose of identifying <a href="#release_sequence">release sequences</a>. A
4857failed <code>cmpxchg</code> is equivalent to an atomic load with an ordering
4858parameter determined by dropping any <code>release</code> part of the
4859<code>cmpxchg</code>'s ordering.</p>
4860
4861<!--
4862FIXME: Is compare_exchange_weak() necessary? (Consider after we've done
4863optimization work on ARM.)
4864
4865FIXME: Is a weaker ordering constraint on failure helpful in practice?
4866-->
4867
4868<h5>Example:</h5>
4869<pre>
4870entry:
4871 %orig = atomic <a href="#i_load">load</a> i32* %ptr unordered <i>; yields {i32}</i>
4872 <a href="#i_br">br</a> label %loop
4873
4874loop:
4875 %cmp = <a href="#i_phi">phi</a> i32 [ %orig, %entry ], [%old, %loop]
4876 %squared = <a href="#i_mul">mul</a> i32 %cmp, %cmp
4877 %old = cmpxchg i32* %ptr, i32 %cmp, i32 %squared <i>; yields {i32}</i>
4878 %success = <a href="#i_icmp">icmp</a> eq i32 %cmp, %old
4879 <a href="#i_br">br</a> i1 %success, label %done, label %loop
4880
4881done:
4882 ...
4883</pre>
4884
4885</div>
4886
4887<!-- _______________________________________________________________________ -->
NAKAMURA Takumi0300d882011-08-12 06:17:17 +0000[diff] [blame]4888<h4>
4889<a name="i_atomicrmw">'<tt>atomicrmw</tt>' Instruction</a>
4890</h4>
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]4891
NAKAMURA Takumi0300d882011-08-12 06:17:17 +0000[diff] [blame]4892<div>
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]4893
4894<h5>Syntax:</h5>
4895<pre>
Eli Friedman02e737b2011-08-12 22:50:01 +0000[diff] [blame]4896 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]4897</pre>
4898
4899<h5>Overview:</h5>
4900<p>The '<tt>atomicrmw</tt>' instruction is used to atomically modify memory.</p>
4901
4902<h5>Arguments:</h5>
4903<p>There are three arguments to the '<code>atomicrmw</code>' instruction: an
4904operation to apply, an address whose value to modify, an argument to the
4905operation. The operation must be one of the following keywords:</p>
4906<ul>
4907 <li>xchg</li>
4908 <li>add</li>
4909 <li>sub</li>
4910 <li>and</li>
4911 <li>nand</li>
4912 <li>or</li>
4913 <li>xor</li>
4914 <li>max</li>
4915 <li>min</li>
4916 <li>umax</li>
4917 <li>umin</li>
4918</ul>
4919
4920<p>The type of '<var>&lt;value&gt;</var>' must be an integer type whose
4921bit width is a power of two greater than or equal to eight and less than
4922or equal to a target-specific size limit. The type of the
4923'<code>&lt;pointer&gt;</code>' operand must be a pointer to that type.
4924If the <code>atomicrmw</code> is marked as <code>volatile</code>, then the
4925optimizer is not allowed to modify the number or order of execution of this
4926<code>atomicrmw</code> with other <a href="#volatile">volatile
4927 operations</a>.</p>
4928
4929<!-- FIXME: Extend allowed types. -->
4930
4931<h5>Semantics:</h5>
4932<p>The contents of memory at the location specified by the
4933'<tt>&lt;pointer&gt;</tt>' operand are atomically read, modified, and written
4934back. The original value at the location is returned. The modification is
4935specified by the <var>operation</var> argument:</p>
4936
4937<ul>
4938 <li>xchg: <code>*ptr = val</code></li>
4939 <li>add: <code>*ptr = *ptr + val</code></li>
4940 <li>sub: <code>*ptr = *ptr - val</code></li>
4941 <li>and: <code>*ptr = *ptr &amp; val</code></li>
4942 <li>nand: <code>*ptr = ~(*ptr &amp; val)</code></li>
4943 <li>or: <code>*ptr = *ptr | val</code></li>
4944 <li>xor: <code>*ptr = *ptr ^ val</code></li>
4945 <li>max: <code>*ptr = *ptr &gt; val ? *ptr : val</code> (using a signed comparison)</li>
4946 <li>min: <code>*ptr = *ptr &lt; val ? *ptr : val</code> (using a signed comparison)</li>
4947 <li>umax: <code>*ptr = *ptr &gt; val ? *ptr : val</code> (using an unsigned comparison)</li>
4948 <li>umin: <code>*ptr = *ptr &lt; val ? *ptr : val</code> (using an unsigned comparison)</li>
4949</ul>
4950
4951<h5>Example:</h5>
4952<pre>
4953 %old = atomicrmw add i32* %ptr, i32 1 acquire <i>; yields {i32}</i>
4954</pre>
4955
4956</div>
4957
4958<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4959<h4>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4960 <a name="i_getelementptr">'<tt>getelementptr</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4961</h4>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4962
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4963<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4964
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]4965<h5>Syntax:</h5>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4966<pre>
Matthijs Kooijman0e268272008-10-13 13:44:15 +0000[diff] [blame]4967 &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]4968 &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]4969</pre>
4970
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]4971<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4972<p>The '<tt>getelementptr</tt>' instruction is used to get the address of a
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]4973 subelement of an <a href="#t_aggregate">aggregate</a> data structure.
4974 It performs address calculation only and does not access memory.</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4975
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]4976<h5>Arguments:</h5>
Matthijs Kooijman0e268272008-10-13 13:44:15 +0000[diff] [blame]4977<p>The first argument is always a pointer, and forms the basis of the
Chris Lattnera40b9122009-07-29 06:44:13 +0000[diff] [blame]4978 calculation. The remaining arguments are indices that indicate which of the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4979 elements of the aggregate object are indexed. The interpretation of each
4980 index is dependent on the type being indexed into. The first index always
4981 indexes the pointer value given as the first argument, the second index
4982 indexes a value of the type pointed to (not necessarily the value directly
4983 pointed to, since the first index can be non-zero), etc. The first type
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]4984 indexed into must be a pointer value, subsequent types can be arrays,
Chris Lattner13ee7952010-08-28 04:09:24 +0000[diff] [blame]4985 vectors, and structs. Note that subsequent types being indexed into
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]4986 can never be pointers, since that would require loading the pointer before
4987 continuing calculation.</p>
Matthijs Kooijman0e268272008-10-13 13:44:15 +0000[diff] [blame]4988
4989<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]4990 When indexing into a (optionally packed) structure, only <tt>i32</tt>
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]4991 integer <b>constants</b> are allowed. When indexing into an array, pointer
4992 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]4993 constant. These integers are treated as signed values where relevant.</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4994
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4995<p>For example, let's consider a C code fragment and how it gets compiled to
4996 LLVM:</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4997
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]4998<pre class="doc_code">
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]4999struct RT {
5000 char A;
Chris Lattnera446f1b2007-05-29 15:43:56 +0000[diff] [blame]5001 int B[10][20];
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]5002 char C;
5003};
5004struct ST {
Chris Lattnera446f1b2007-05-29 15:43:56 +0000[diff] [blame]5005 int X;
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]5006 double Y;
5007 struct RT Z;
5008};
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]5009
Chris Lattnera446f1b2007-05-29 15:43:56 +0000[diff] [blame]5010int *foo(struct ST *s) {
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]5011 return &amp;s[1].Z.B[5][13];
5012}
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]5013</pre>
5014
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5015<p>The LLVM code generated by the GCC frontend is:</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]5016
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]5017<pre class="doc_code">
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]5018%RT = <a href="#namedtypes">type</a> { i8 , [10 x [20 x i32]], i8 }
5019%ST = <a href="#namedtypes">type</a> { i32, double, %RT }
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]5020
Dan Gohman6b867702009-07-25 02:23:48 +0000[diff] [blame]5021define i32* @foo(%ST* %s) {
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]5022entry:
5023 %reg = getelementptr %ST* %s, i32 1, i32 2, i32 1, i32 5, i32 13
5024 ret i32* %reg
5025}
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]5026</pre>
5027
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]5028<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5029<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]5030 type, which is a pointer, yielding a '<tt>%ST</tt>' = '<tt>{ i32, double, %RT
5031 }</tt>' type, a structure. The second index indexes into the third element
5032 of the structure, yielding a '<tt>%RT</tt>' = '<tt>{ i8 , [10 x [20 x i32]],
5033 i8 }</tt>' type, another structure. The third index indexes into the second
5034 element of the structure, yielding a '<tt>[10 x [20 x i32]]</tt>' type, an
5035 array. The two dimensions of the array are subscripted into, yielding an
5036 '<tt>i32</tt>' type. The '<tt>getelementptr</tt>' instruction returns a
5037 pointer to this element, thus computing a value of '<tt>i32*</tt>' type.</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]5038
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5039<p>Note that it is perfectly legal to index partially through a structure,
5040 returning a pointer to an inner element. Because of this, the LLVM code for
5041 the given testcase is equivalent to:</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]5042
5043<pre>
Dan Gohman6b867702009-07-25 02:23:48 +0000[diff] [blame]5044 define i32* @foo(%ST* %s) {
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]5045 %t1 = getelementptr %ST* %s, i32 1 <i>; yields %ST*:%t1</i>
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]5046 %t2 = getelementptr %ST* %t1, i32 0, i32 2 <i>; yields %RT*:%t2</i>
5047 %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]5048 %t4 = getelementptr [10 x [20 x i32]]* %t3, i32 0, i32 5 <i>; yields [20 x i32]*:%t4</i>
5049 %t5 = getelementptr [20 x i32]* %t4, i32 0, i32 13 <i>; yields i32*:%t5</i>
5050 ret i32* %t5
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]5051 }
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]5052</pre>
Chris Lattnerc0ad71e2005-06-24 17:22:57 +0000[diff] [blame]5053
Dan Gohman1639c392009-07-27 21:53:46 +0000[diff] [blame]5054<p>If the <tt>inbounds</tt> keyword is present, the result value of the
Dan Gohman57255802010-04-23 15:23:32 +0000[diff] [blame]5055 <tt>getelementptr</tt> is a <a href="#trapvalues">trap value</a> if the
5056 base pointer is not an <i>in bounds</i> address of an allocated object,
5057 or if any of the addresses that would be formed by successive addition of
5058 the offsets implied by the indices to the base address with infinitely
Eli Friedmand8874dc2011-08-12 23:37:55 +0000[diff] [blame]5059 precise signed arithmetic are not an <i>in bounds</i> address of that
5060 allocated object. The <i>in bounds</i> addresses for an allocated object
5061 are all the addresses that point into the object, plus the address one
5062 byte past the end.</p>
Dan Gohman1639c392009-07-27 21:53:46 +0000[diff] [blame]5063
5064<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]5065 the base address with silently-wrapping two's complement arithmetic. If the
5066 offsets have a different width from the pointer, they are sign-extended or
5067 truncated to the width of the pointer. The result value of the
5068 <tt>getelementptr</tt> may be outside the object pointed to by the base
5069 pointer. The result value may not necessarily be used to access memory
5070 though, even if it happens to point into allocated storage. See the
5071 <a href="#pointeraliasing">Pointer Aliasing Rules</a> section for more
5072 information.</p>
Dan Gohman1639c392009-07-27 21:53:46 +0000[diff] [blame]5073
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5074<p>The getelementptr instruction is often confusing. For some more insight into
5075 how it works, see <a href="GetElementPtr.html">the getelementptr FAQ</a>.</p>
Chris Lattner6ab66722006-08-15 00:45:58 +0000[diff] [blame]5076
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]5077<h5>Example:</h5>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]5078<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]5079 <i>; yields [12 x i8]*:aptr</i>
Matthijs Kooijman0e268272008-10-13 13:44:15 +0000[diff] [blame]5080 %aptr = getelementptr {i32, [12 x i8]}* %saptr, i64 0, i32 1
5081 <i>; yields i8*:vptr</i>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]5082 %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]5083 <i>; yields i8*:eptr</i>
5084 %eptr = getelementptr [12 x i8]* %aptr, i64 0, i32 1
Sanjiv Gupta0c155e62009-04-25 07:27:44 +0000[diff] [blame]5085 <i>; yields i32*:iptr</i>
Sanjiv Gupta77abea02009-04-24 16:38:13 +0000[diff] [blame]5086 %iptr = getelementptr [10 x i32]* @arr, i16 0, i16 0
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]5087</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5088
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]5089</div>
Reid Spencer443460a2006-11-09 21:15:49 +0000[diff] [blame]5090
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5091</div>
5092
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]5093<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5094<h3>
5095 <a name="convertops">Conversion Operations</a>
5096</h3>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5097
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5098<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5099
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5100<p>The instructions in this category are the conversion instructions (casting)
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5101 which all take a single operand and a type. They perform various bit
5102 conversions on the operand.</p>
5103
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]5104<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5105<h4>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5106 <a name="i_trunc">'<tt>trunc .. to</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5107</h4>
5108
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5109<div>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5110
5111<h5>Syntax:</h5>
5112<pre>
5113 &lt;result&gt; = trunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
5114</pre>
5115
5116<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5117<p>The '<tt>trunc</tt>' instruction truncates its operand to the
5118 type <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5119
5120<h5>Arguments:</h5>
Nadav Rotem502f1b92011-02-24 21:01:34 +0000[diff] [blame]5121<p>The '<tt>trunc</tt>' instruction takes a value to trunc, and a type to trunc it to.
5122 Both types must be of <a href="#t_integer">integer</a> types, or vectors
5123 of the same number of integers.
5124 The bit size of the <tt>value</tt> must be larger than
5125 the bit size of the destination type, <tt>ty2</tt>.
5126 Equal sized types are not allowed.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5127
5128<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5129<p>The '<tt>trunc</tt>' instruction truncates the high order bits
5130 in <tt>value</tt> and converts the remaining bits to <tt>ty2</tt>. Since the
5131 source size must be larger than the destination size, <tt>trunc</tt> cannot
5132 be a <i>no-op cast</i>. It will always truncate bits.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5133
5134<h5>Example:</h5>
5135<pre>
Nadav Rotem502f1b92011-02-24 21:01:34 +0000[diff] [blame]5136 %X = trunc i32 257 to i8 <i>; yields i8:1</i>
5137 %Y = trunc i32 123 to i1 <i>; yields i1:true</i>
5138 %Z = trunc i32 122 to i1 <i>; yields i1:false</i>
5139 %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]5140</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5141
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5142</div>
5143
5144<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5145<h4>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5146 <a name="i_zext">'<tt>zext .. to</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5147</h4>
5148
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5149<div>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5150
5151<h5>Syntax:</h5>
5152<pre>
5153 &lt;result&gt; = zext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
5154</pre>
5155
5156<h5>Overview:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5157<p>The '<tt>zext</tt>' instruction zero extends its operand to type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5158 <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5159
5160
5161<h5>Arguments:</h5>
Nadav Rotem25f2ac92011-02-20 12:37:50 +0000[diff] [blame]5162<p>The '<tt>zext</tt>' instruction takes a value to cast, and a type to cast it to.
5163 Both types must be of <a href="#t_integer">integer</a> types, or vectors
5164 of the same number of integers.
5165 The bit size of the <tt>value</tt> must be smaller than
5166 the bit size of the destination type,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5167 <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5168
5169<h5>Semantics:</h5>
5170<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]5171 bits until it reaches the size of the destination type, <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5172
Reid Spencer07c9c682007-01-12 15:46:11 +0000[diff] [blame]5173<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]5174
5175<h5>Example:</h5>
5176<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]5177 %X = zext i32 257 to i64 <i>; yields i64:257</i>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]5178 %Y = zext i1 true to i32 <i>; yields i32:1</i>
Nadav Rotem25f2ac92011-02-20 12:37:50 +0000[diff] [blame]5179 %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]5180</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5181
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5182</div>
5183
5184<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5185<h4>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5186 <a name="i_sext">'<tt>sext .. to</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5187</h4>
5188
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5189<div>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5190
5191<h5>Syntax:</h5>
5192<pre>
5193 &lt;result&gt; = sext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
5194</pre>
5195
5196<h5>Overview:</h5>
5197<p>The '<tt>sext</tt>' sign extends <tt>value</tt> to the type <tt>ty2</tt>.</p>
5198
5199<h5>Arguments:</h5>
Nadav Rotem502f1b92011-02-24 21:01:34 +0000[diff] [blame]5200<p>The '<tt>sext</tt>' instruction takes a value to cast, and a type to cast it to.
5201 Both types must be of <a href="#t_integer">integer</a> types, or vectors
5202 of the same number of integers.
5203 The bit size of the <tt>value</tt> must be smaller than
5204 the bit size of the destination type,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5205 <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5206
5207<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5208<p>The '<tt>sext</tt>' instruction performs a sign extension by copying the sign
5209 bit (highest order bit) of the <tt>value</tt> until it reaches the bit size
5210 of the type <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5211
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]5212<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]5213
5214<h5>Example:</h5>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5215<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]5216 %X = sext i8 -1 to i16 <i>; yields i16 :65535</i>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]5217 %Y = sext i1 true to i32 <i>; yields i32:-1</i>
Nadav Rotem502f1b92011-02-24 21:01:34 +0000[diff] [blame]5218 %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]5219</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5220
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5221</div>
5222
5223<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5224<h4>
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]5225 <a name="i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5226</h4>
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]5227
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5228<div>
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]5229
5230<h5>Syntax:</h5>
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]5231<pre>
5232 &lt;result&gt; = fptrunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
5233</pre>
5234
5235<h5>Overview:</h5>
5236<p>The '<tt>fptrunc</tt>' instruction truncates <tt>value</tt> to type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5237 <tt>ty2</tt>.</p>
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]5238
5239<h5>Arguments:</h5>
5240<p>The '<tt>fptrunc</tt>' instruction takes a <a href="#t_floating">floating
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5241 point</a> value to cast and a <a href="#t_floating">floating point</a> type
5242 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]5243 <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]5244 <i>no-op cast</i>.</p>
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]5245
5246<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5247<p>The '<tt>fptrunc</tt>' instruction truncates a <tt>value</tt> from a larger
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5248 <a href="#t_floating">floating point</a> type to a smaller
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5249 <a href="#t_floating">floating point</a> type. If the value cannot fit
5250 within the destination type, <tt>ty2</tt>, then the results are
5251 undefined.</p>
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]5252
5253<h5>Example:</h5>
5254<pre>
5255 %X = fptrunc double 123.0 to float <i>; yields float:123.0</i>
5256 %Y = fptrunc double 1.0E+300 to float <i>; yields undefined</i>
5257</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5258
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]5259</div>
5260
5261<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5262<h4>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5263 <a name="i_fpext">'<tt>fpext .. to</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5264</h4>
5265
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5266<div>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5267
5268<h5>Syntax:</h5>
5269<pre>
5270 &lt;result&gt; = fpext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
5271</pre>
5272
5273<h5>Overview:</h5>
5274<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]5275 floating point value.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5276
5277<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5278<p>The '<tt>fpext</tt>' instruction takes a
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5279 <a href="#t_floating">floating point</a> <tt>value</tt> to cast, and
5280 a <a href="#t_floating">floating point</a> type to cast it to. The source
5281 type must be smaller than the destination type.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5282
5283<h5>Semantics:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]5284<p>The '<tt>fpext</tt>' instruction extends the <tt>value</tt> from a smaller
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5285 <a href="#t_floating">floating point</a> type to a larger
5286 <a href="#t_floating">floating point</a> type. The <tt>fpext</tt> cannot be
5287 used to make a <i>no-op cast</i> because it always changes bits. Use
5288 <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]5289
5290<h5>Example:</h5>
5291<pre>
Nick Lewycky9feca672011-03-31 18:20:19 +0000[diff] [blame]5292 %X = fpext float 3.125 to double <i>; yields double:3.125000e+00</i>
5293 %Y = fpext double %X to fp128 <i>; yields fp128:0xL00000000000000004000900000000000</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5294</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5295
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5296</div>
5297
5298<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5299<h4>
Reid Spencer2eadb532007-01-21 00:29:26 +0000[diff] [blame]5300 <a name="i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5301</h4>
5302
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5303<div>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5304
5305<h5>Syntax:</h5>
5306<pre>
Reid Spencer753163d2007-07-31 14:40:14 +0000[diff] [blame]5307 &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]5308</pre>
5309
5310<h5>Overview:</h5>
Reid Spencer753163d2007-07-31 14:40:14 +0000[diff] [blame]5311<p>The '<tt>fptoui</tt>' converts a floating point <tt>value</tt> to its
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5312 unsigned integer equivalent of type <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5313
5314<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5315<p>The '<tt>fptoui</tt>' instruction takes a value to cast, which must be a
5316 scalar or vector <a href="#t_floating">floating point</a> value, and a type
5317 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
5318 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
5319 vector integer type with the same number of elements as <tt>ty</tt></p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5320
5321<h5>Semantics:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5322<p>The '<tt>fptoui</tt>' instruction converts its
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5323 <a href="#t_floating">floating point</a> operand into the nearest (rounding
5324 towards zero) unsigned integer value. If the value cannot fit
5325 in <tt>ty2</tt>, the results are undefined.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5326
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5327<h5>Example:</h5>
5328<pre>
Reid Spencer753163d2007-07-31 14:40:14 +0000[diff] [blame]5329 %X = fptoui double 123.0 to i32 <i>; yields i32:123</i>
Chris Lattner5b95a172007-09-22 03:17:52 +0000[diff] [blame]5330 %Y = fptoui float 1.0E+300 to i1 <i>; yields undefined:1</i>
Gabor Greiff50fd572009-10-28 09:21:30 +0000[diff] [blame]5331 %Z = fptoui float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5332</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5333
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5334</div>
5335
5336<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5337<h4>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]5338 <a name="i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5339</h4>
5340
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5341<div>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5342
5343<h5>Syntax:</h5>
5344<pre>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]5345 &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]5346</pre>
5347
5348<h5>Overview:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5349<p>The '<tt>fptosi</tt>' instruction converts
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5350 <a href="#t_floating">floating point</a> <tt>value</tt> to
5351 type <tt>ty2</tt>.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5352
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]5353<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5354<p>The '<tt>fptosi</tt>' instruction takes a value to cast, which must be a
5355 scalar or vector <a href="#t_floating">floating point</a> value, and a type
5356 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
5357 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
5358 vector integer type with the same number of elements as <tt>ty</tt></p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5359
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]5360<h5>Semantics:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5361<p>The '<tt>fptosi</tt>' instruction converts its
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5362 <a href="#t_floating">floating point</a> operand into the nearest (rounding
5363 towards zero) signed integer value. If the value cannot fit in <tt>ty2</tt>,
5364 the results are undefined.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5365
Chris Lattner70de6632001-07-09 00:26:23 +0000[diff] [blame]5366<h5>Example:</h5>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5367<pre>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]5368 %X = fptosi double -123.0 to i32 <i>; yields i32:-123</i>
Chris Lattner5b95a172007-09-22 03:17:52 +0000[diff] [blame]5369 %Y = fptosi float 1.0E-247 to i1 <i>; yields undefined:1</i>
Gabor Greiff50fd572009-10-28 09:21:30 +0000[diff] [blame]5370 %Z = fptosi float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5371</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5372
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5373</div>
5374
5375<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5376<h4>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]5377 <a name="i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5378</h4>
5379
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5380<div>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5381
5382<h5>Syntax:</h5>
5383<pre>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]5384 &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]5385</pre>
5386
5387<h5>Overview:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]5388<p>The '<tt>uitofp</tt>' instruction regards <tt>value</tt> as an unsigned
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5389 integer and converts that value to the <tt>ty2</tt> type.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5390
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5391<h5>Arguments:</h5>
Nate Begemand4d45c22007-11-17 03:58:34 +0000[diff] [blame]5392<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]5393 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
5394 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
5395 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
5396 floating point type with the same number of elements as <tt>ty</tt></p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5397
5398<h5>Semantics:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]5399<p>The '<tt>uitofp</tt>' instruction interprets its operand as an unsigned
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5400 integer quantity and converts it to the corresponding floating point
5401 value. If the value cannot fit in the floating point value, the results are
5402 undefined.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5403
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5404<h5>Example:</h5>
5405<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]5406 %X = uitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]5407 %Y = uitofp i8 -1 to double <i>; yields double:255.0</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5408</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5409
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5410</div>
5411
5412<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5413<h4>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]5414 <a name="i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5415</h4>
5416
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5417<div>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5418
5419<h5>Syntax:</h5>
5420<pre>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]5421 &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]5422</pre>
5423
5424<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5425<p>The '<tt>sitofp</tt>' instruction regards <tt>value</tt> as a signed integer
5426 and converts that value to the <tt>ty2</tt> type.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5427
5428<h5>Arguments:</h5>
Nate Begemand4d45c22007-11-17 03:58:34 +0000[diff] [blame]5429<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]5430 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
5431 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
5432 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
5433 floating point type with the same number of elements as <tt>ty</tt></p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5434
5435<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5436<p>The '<tt>sitofp</tt>' instruction interprets its operand as a signed integer
5437 quantity and converts it to the corresponding floating point value. If the
5438 value cannot fit in the floating point value, the results are undefined.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5439
5440<h5>Example:</h5>
5441<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]5442 %X = sitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]5443 %Y = sitofp i8 -1 to double <i>; yields double:-1.0</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5444</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5445
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5446</div>
5447
5448<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5449<h4>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]5450 <a name="i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5451</h4>
5452
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5453<div>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]5454
5455<h5>Syntax:</h5>
5456<pre>
5457 &lt;result&gt; = ptrtoint &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
5458</pre>
5459
5460<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5461<p>The '<tt>ptrtoint</tt>' instruction converts the pointer <tt>value</tt> to
5462 the integer type <tt>ty2</tt>.</p>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]5463
5464<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5465<p>The '<tt>ptrtoint</tt>' instruction takes a <tt>value</tt> to cast, which
5466 must be a <a href="#t_pointer">pointer</a> value, and a type to cast it to
5467 <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]5468
5469<h5>Semantics:</h5>
5470<p>The '<tt>ptrtoint</tt>' instruction converts <tt>value</tt> to integer type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5471 <tt>ty2</tt> by interpreting the pointer value as an integer and either
5472 truncating or zero extending that value to the size of the integer type. If
5473 <tt>value</tt> is smaller than <tt>ty2</tt> then a zero extension is done. If
5474 <tt>value</tt> is larger than <tt>ty2</tt> then a truncation is done. If they
5475 are the same size, then nothing is done (<i>no-op cast</i>) other than a type
5476 change.</p>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]5477
5478<h5>Example:</h5>
5479<pre>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5480 %X = ptrtoint i32* %X to i8 <i>; yields truncation on 32-bit architecture</i>
5481 %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]5482</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5483
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]5484</div>
5485
5486<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5487<h4>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]5488 <a name="i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5489</h4>
5490
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5491<div>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]5492
5493<h5>Syntax:</h5>
5494<pre>
5495 &lt;result&gt; = inttoptr &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
5496</pre>
5497
5498<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5499<p>The '<tt>inttoptr</tt>' instruction converts an integer <tt>value</tt> to a
5500 pointer type, <tt>ty2</tt>.</p>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]5501
5502<h5>Arguments:</h5>
Duncan Sands16f122e2007-03-30 12:22:09 +0000[diff] [blame]5503<p>The '<tt>inttoptr</tt>' instruction takes an <a href="#t_integer">integer</a>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5504 value to cast, and a type to cast it to, which must be a
5505 <a href="#t_pointer">pointer</a> type.</p>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]5506
5507<h5>Semantics:</h5>
5508<p>The '<tt>inttoptr</tt>' instruction converts <tt>value</tt> to type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5509 <tt>ty2</tt> by applying either a zero extension or a truncation depending on
5510 the size of the integer <tt>value</tt>. If <tt>value</tt> is larger than the
5511 size of a pointer then a truncation is done. If <tt>value</tt> is smaller
5512 than the size of a pointer then a zero extension is done. If they are the
5513 same size, nothing is done (<i>no-op cast</i>).</p>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]5514
5515<h5>Example:</h5>
5516<pre>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5517 %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]5518 %Y = inttoptr i32 255 to i32* <i>; yields no-op on 32-bit architecture</i>
5519 %Z = inttoptr i64 0 to i32* <i>; yields truncation on 32-bit architecture</i>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]5520</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5521
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]5522</div>
5523
5524<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5525<h4>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]5526 <a name="i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5527</h4>
5528
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5529<div>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5530
5531<h5>Syntax:</h5>
5532<pre>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]5533 &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]5534</pre>
5535
5536<h5>Overview:</h5>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]5537<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5538 <tt>ty2</tt> without changing any bits.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5539
5540<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5541<p>The '<tt>bitcast</tt>' instruction takes a value to cast, which must be a
5542 non-aggregate first class value, and a type to cast it to, which must also be
5543 a non-aggregate <a href="#t_firstclass">first class</a> type. The bit sizes
5544 of <tt>value</tt> and the destination type, <tt>ty2</tt>, must be
5545 identical. If the source type is a pointer, the destination type must also be
5546 a pointer. This instruction supports bitwise conversion of vectors to
5547 integers and to vectors of other types (as long as they have the same
5548 size).</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5549
5550<h5>Semantics:</h5>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]5551<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5552 <tt>ty2</tt>. It is always a <i>no-op cast</i> because no bits change with
5553 this conversion. The conversion is done as if the <tt>value</tt> had been
5554 stored to memory and read back as type <tt>ty2</tt>. Pointer types may only
5555 be converted to other pointer types with this instruction. To convert
5556 pointers to other types, use the <a href="#i_inttoptr">inttoptr</a> or
5557 <a href="#i_ptrtoint">ptrtoint</a> instructions first.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5558
5559<h5>Example:</h5>
5560<pre>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5561 %X = bitcast i8 255 to i8 <i>; yields i8 :-1</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]5562 %Y = bitcast i32* %x to sint* <i>; yields sint*:%x</i>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5563 %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]5564</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5565
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5566</div>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5567
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5568</div>
5569
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5570<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5571<h3>
5572 <a name="otherops">Other Operations</a>
5573</h3>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5574
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5575<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5576
5577<p>The instructions in this category are the "miscellaneous" instructions, which
5578 defy better classification.</p>
5579
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5580<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5581<h4>
5582 <a name="i_icmp">'<tt>icmp</tt>' Instruction</a>
5583</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5584
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5585<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5586
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5587<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5588<pre>
5589 &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]5590</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5591
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5592<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5593<p>The '<tt>icmp</tt>' instruction returns a boolean value or a vector of
5594 boolean values based on comparison of its two integer, integer vector, or
5595 pointer operands.</p>
5596
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5597<h5>Arguments:</h5>
5598<p>The '<tt>icmp</tt>' instruction takes three operands. The first operand is
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5599 the condition code indicating the kind of comparison to perform. It is not a
5600 value, just a keyword. The possible condition code are:</p>
5601
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5602<ol>
5603 <li><tt>eq</tt>: equal</li>
5604 <li><tt>ne</tt>: not equal </li>
5605 <li><tt>ugt</tt>: unsigned greater than</li>
5606 <li><tt>uge</tt>: unsigned greater or equal</li>
5607 <li><tt>ult</tt>: unsigned less than</li>
5608 <li><tt>ule</tt>: unsigned less or equal</li>
5609 <li><tt>sgt</tt>: signed greater than</li>
5610 <li><tt>sge</tt>: signed greater or equal</li>
5611 <li><tt>slt</tt>: signed less than</li>
5612 <li><tt>sle</tt>: signed less or equal</li>
5613</ol>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5614
Chris Lattnerc0f423a2007-01-15 01:54:13 +0000[diff] [blame]5615<p>The remaining two arguments must be <a href="#t_integer">integer</a> or
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5616 <a href="#t_pointer">pointer</a> or integer <a href="#t_vector">vector</a>
5617 typed. They must also be identical types.</p>
5618
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5619<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5620<p>The '<tt>icmp</tt>' compares <tt>op1</tt> and <tt>op2</tt> according to the
5621 condition code given as <tt>cond</tt>. The comparison performed always yields
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]5622 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]5623 result, as follows:</p>
5624
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5625<ol>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5626 <li><tt>eq</tt>: yields <tt>true</tt> if the operands are equal,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5627 <tt>false</tt> otherwise. No sign interpretation is necessary or
5628 performed.</li>
5629
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5630 <li><tt>ne</tt>: yields <tt>true</tt> if the operands are unequal,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5631 <tt>false</tt> otherwise. No sign interpretation is necessary or
5632 performed.</li>
5633
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5634 <li><tt>ugt</tt>: interprets the operands as unsigned values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5635 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
5636
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5637 <li><tt>uge</tt>: interprets the operands as unsigned values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5638 <tt>true</tt> if <tt>op1</tt> is greater than or equal
5639 to <tt>op2</tt>.</li>
5640
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5641 <li><tt>ult</tt>: interprets the operands as unsigned values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5642 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
5643
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5644 <li><tt>ule</tt>: interprets the operands as unsigned values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5645 <tt>true</tt> if <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
5646
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5647 <li><tt>sgt</tt>: interprets the operands as signed values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5648 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
5649
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5650 <li><tt>sge</tt>: interprets the operands as signed values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5651 <tt>true</tt> if <tt>op1</tt> is greater than or equal
5652 to <tt>op2</tt>.</li>
5653
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5654 <li><tt>slt</tt>: interprets the operands as signed values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5655 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
5656
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5657 <li><tt>sle</tt>: interprets the operands as signed values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5658 <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]5659</ol>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5660
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5661<p>If the operands are <a href="#t_pointer">pointer</a> typed, the pointer
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5662 values are compared as if they were integers.</p>
5663
5664<p>If the operands are integer vectors, then they are compared element by
5665 element. The result is an <tt>i1</tt> vector with the same number of elements
5666 as the values being compared. Otherwise, the result is an <tt>i1</tt>.</p>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5667
5668<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5669<pre>
5670 &lt;result&gt; = icmp eq i32 4, 5 <i>; yields: result=false</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]5671 &lt;result&gt; = icmp ne float* %X, %X <i>; yields: result=false</i>
5672 &lt;result&gt; = icmp ult i16 4, 5 <i>; yields: result=true</i>
5673 &lt;result&gt; = icmp sgt i16 4, 5 <i>; yields: result=false</i>
5674 &lt;result&gt; = icmp ule i16 -4, 5 <i>; yields: result=false</i>
5675 &lt;result&gt; = icmp sge i16 4, 5 <i>; yields: result=false</i>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5676</pre>
Dan Gohmana5127ab2009-01-22 01:39:38 +0000[diff] [blame]5677
5678<p>Note that the code generator does not yet support vector types with
5679 the <tt>icmp</tt> instruction.</p>
5680
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5681</div>
5682
5683<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5684<h4>
5685 <a name="i_fcmp">'<tt>fcmp</tt>' Instruction</a>
5686</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5687
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5688<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5689
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5690<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5691<pre>
5692 &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]5693</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5694
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5695<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5696<p>The '<tt>fcmp</tt>' instruction returns a boolean value or vector of boolean
5697 values based on comparison of its operands.</p>
5698
5699<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]5700(<a href="#t_integer"><tt>i1</tt></a>).</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5701
5702<p>If the operands are floating point vectors, then the result type is a vector
5703 of boolean with the same number of elements as the operands being
5704 compared.</p>
5705
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5706<h5>Arguments:</h5>
5707<p>The '<tt>fcmp</tt>' instruction takes three operands. The first operand is
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5708 the condition code indicating the kind of comparison to perform. It is not a
5709 value, just a keyword. The possible condition code are:</p>
5710
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5711<ol>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]5712 <li><tt>false</tt>: no comparison, always returns false</li>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5713 <li><tt>oeq</tt>: ordered and equal</li>
5714 <li><tt>ogt</tt>: ordered and greater than </li>
5715 <li><tt>oge</tt>: ordered and greater than or equal</li>
5716 <li><tt>olt</tt>: ordered and less than </li>
5717 <li><tt>ole</tt>: ordered and less than or equal</li>
5718 <li><tt>one</tt>: ordered and not equal</li>
5719 <li><tt>ord</tt>: ordered (no nans)</li>
5720 <li><tt>ueq</tt>: unordered or equal</li>
5721 <li><tt>ugt</tt>: unordered or greater than </li>
5722 <li><tt>uge</tt>: unordered or greater than or equal</li>
5723 <li><tt>ult</tt>: unordered or less than </li>
5724 <li><tt>ule</tt>: unordered or less than or equal</li>
5725 <li><tt>une</tt>: unordered or not equal</li>
5726 <li><tt>uno</tt>: unordered (either nans)</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]5727 <li><tt>true</tt>: no comparison, always returns true</li>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5728</ol>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5729
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5730<p><i>Ordered</i> means that neither operand is a QNAN while
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5731 <i>unordered</i> means that either operand may be a QNAN.</p>
5732
5733<p>Each of <tt>val1</tt> and <tt>val2</tt> arguments must be either
5734 a <a href="#t_floating">floating point</a> type or
5735 a <a href="#t_vector">vector</a> of floating point type. They must have
5736 identical types.</p>
5737
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5738<h5>Semantics:</h5>
Gabor Greif0f75ad02008-08-07 21:46:00 +0000[diff] [blame]5739<p>The '<tt>fcmp</tt>' instruction compares <tt>op1</tt> and <tt>op2</tt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5740 according to the condition code given as <tt>cond</tt>. If the operands are
5741 vectors, then the vectors are compared element by element. Each comparison
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]5742 performed always yields an <a href="#t_integer">i1</a> result, as
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5743 follows:</p>
5744
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5745<ol>
5746 <li><tt>false</tt>: always yields <tt>false</tt>, regardless of operands.</li>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5747
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5748 <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]5749 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
5750
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]5751 <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]5752 <tt>op1</tt> is greater than <tt>op2</tt>.</li>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5753
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5754 <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]5755 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
5756
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5757 <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]5758 <tt>op1</tt> is less than <tt>op2</tt>.</li>
5759
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5760 <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]5761 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
5762
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5763 <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]5764 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
5765
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]5766 <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]5767
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5768 <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]5769 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
5770
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5771 <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]5772 <tt>op1</tt> is greater than <tt>op2</tt>.</li>
5773
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5774 <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]5775 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
5776
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5777 <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]5778 <tt>op1</tt> is less than <tt>op2</tt>.</li>
5779
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5780 <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]5781 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
5782
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5783 <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]5784 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
5785
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]5786 <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]5787
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5788 <li><tt>true</tt>: always yields <tt>true</tt>, regardless of operands.</li>
5789</ol>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5790
5791<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5792<pre>
5793 &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]5794 &lt;result&gt; = fcmp one float 4.0, 5.0 <i>; yields: result=true</i>
5795 &lt;result&gt; = fcmp olt float 4.0, 5.0 <i>; yields: result=true</i>
5796 &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]5797</pre>
Dan Gohmana5127ab2009-01-22 01:39:38 +0000[diff] [blame]5798
5799<p>Note that the code generator does not yet support vector types with
5800 the <tt>fcmp</tt> instruction.</p>
5801
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5802</div>
5803
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5804<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5805<h4>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]5806 <a name="i_phi">'<tt>phi</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5807</h4>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]5808
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5809<div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]5810
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5811<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5812<pre>
5813 &lt;result&gt; = phi &lt;ty&gt; [ &lt;val0&gt;, &lt;label0&gt;], ...
5814</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]5815
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5816<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5817<p>The '<tt>phi</tt>' instruction is used to implement the &#966; node in the
5818 SSA graph representing the function.</p>
5819
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5820<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5821<p>The type of the incoming values is specified with the first type field. After
5822 this, the '<tt>phi</tt>' instruction takes a list of pairs as arguments, with
5823 one pair for each predecessor basic block of the current block. Only values
5824 of <a href="#t_firstclass">first class</a> type may be used as the value
5825 arguments to the PHI node. Only labels may be used as the label
5826 arguments.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]5827
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5828<p>There must be no non-phi instructions between the start of a basic block and
5829 the PHI instructions: i.e. PHI instructions must be first in a basic
5830 block.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]5831
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5832<p>For the purposes of the SSA form, the use of each incoming value is deemed to
5833 occur on the edge from the corresponding predecessor block to the current
5834 block (but after any definition of an '<tt>invoke</tt>' instruction's return
5835 value on the same edge).</p>
Jay Foad1a4eea52009-06-03 10:20:10 +0000[diff] [blame]5836
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5837<h5>Semantics:</h5>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5838<p>At runtime, the '<tt>phi</tt>' instruction logically takes on the value
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5839 specified by the pair corresponding to the predecessor basic block that
5840 executed just prior to the current block.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]5841
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5842<h5>Example:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]5843<pre>
5844Loop: ; Infinite loop that counts from 0 on up...
5845 %indvar = phi i32 [ 0, %LoopHeader ], [ %nextindvar, %Loop ]
5846 %nextindvar = add i32 %indvar, 1
5847 br label %Loop
5848</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5849
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5850</div>
5851
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5852<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5853<h4>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5854 <a name="i_select">'<tt>select</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5855</h4>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5856
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5857<div>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5858
5859<h5>Syntax:</h5>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5860<pre>
Dan Gohmanc579d972008-09-09 01:02:47 +0000[diff] [blame]5861 &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>
5862
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]5863 <i>selty</i> is either i1 or {&lt;N x i1&gt;}
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5864</pre>
5865
5866<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5867<p>The '<tt>select</tt>' instruction is used to choose one value based on a
5868 condition, without branching.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5869
5870
5871<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5872<p>The '<tt>select</tt>' instruction requires an 'i1' value or a vector of 'i1'
5873 values indicating the condition, and two values of the
5874 same <a href="#t_firstclass">first class</a> type. If the val1/val2 are
5875 vectors and the condition is a scalar, then entire vectors are selected, not
5876 individual elements.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5877
5878<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5879<p>If the condition is an i1 and it evaluates to 1, the instruction returns the
5880 first value argument; otherwise, it returns the second value argument.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5881
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5882<p>If the condition is a vector of i1, then the value arguments must be vectors
5883 of the same size, and the selection is done element by element.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5884
5885<h5>Example:</h5>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5886<pre>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]5887 %X = select i1 true, i8 17, i8 42 <i>; yields i8:17</i>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5888</pre>
Dan Gohmana5127ab2009-01-22 01:39:38 +0000[diff] [blame]5889
5890<p>Note that the code generator does not yet support conditions
5891 with vector type.</p>
5892
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5893</div>
5894
Robert Bocchinof72fdfe2006-01-15 20:48:27 +0000[diff] [blame]5895<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5896<h4>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5897 <a name="i_call">'<tt>call</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5898</h4>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5899
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5900<div>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5901
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]5902<h5>Syntax:</h5>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5903<pre>
Devang Patel02256232008-10-07 17:48:33 +0000[diff] [blame]5904 &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]5905</pre>
5906
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]5907<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5908<p>The '<tt>call</tt>' instruction represents a simple function call.</p>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5909
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]5910<h5>Arguments:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5911<p>This instruction requires several arguments:</p>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5912
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]5913<ol>
Jeffrey Yasskinb8677462010-01-09 19:44:16 +0000[diff] [blame]5914 <li>The optional "tail" marker indicates that the callee function does not
5915 access any allocas or varargs in the caller. Note that calls may be
5916 marked "tail" even if they do not occur before
5917 a <a href="#i_ret"><tt>ret</tt></a> instruction. If the "tail" marker is
5918 present, the function call is eligible for tail call optimization,
5919 but <a href="CodeGenerator.html#tailcallopt">might not in fact be
Evan Cheng59676492010-03-08 21:05:02 +0000[diff] [blame]5920 optimized into a jump</a>. The code generator may optimize calls marked
5921 "tail" with either 1) automatic <a href="CodeGenerator.html#sibcallopt">
5922 sibling call optimization</a> when the caller and callee have
5923 matching signatures, or 2) forced tail call optimization when the
5924 following extra requirements are met:
Jeffrey Yasskinb8677462010-01-09 19:44:16 +0000[diff] [blame]5925 <ul>
5926 <li>Caller and callee both have the calling
5927 convention <tt>fastcc</tt>.</li>
5928 <li>The call is in tail position (ret immediately follows call and ret
5929 uses value of call or is void).</li>
5930 <li>Option <tt>-tailcallopt</tt> is enabled,
Dan Gohman6232f732010-03-02 01:08:11 +0000[diff] [blame]5931 or <code>llvm::GuaranteedTailCallOpt</code> is <code>true</code>.</li>
Jeffrey Yasskinb8677462010-01-09 19:44:16 +0000[diff] [blame]5932 <li><a href="CodeGenerator.html#tailcallopt">Platform specific
5933 constraints are met.</a></li>
5934 </ul>
5935 </li>
Devang Patel7e9b05e2008-10-06 18:50:38 +0000[diff] [blame]5936
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5937 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
5938 convention</a> the call should use. If none is specified, the call
Jeffrey Yasskinb8677462010-01-09 19:44:16 +0000[diff] [blame]5939 defaults to using C calling conventions. The calling convention of the
5940 call must match the calling convention of the target function, or else the
5941 behavior is undefined.</li>
Devang Patel7e9b05e2008-10-06 18:50:38 +0000[diff] [blame]5942
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5943 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
5944 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
5945 '<tt>inreg</tt>' attributes are valid here.</li>
5946
5947 <li>'<tt>ty</tt>': the type of the call instruction itself which is also the
5948 type of the return value. Functions that return no value are marked
5949 <tt><a href="#t_void">void</a></tt>.</li>
5950
5951 <li>'<tt>fnty</tt>': shall be the signature of the pointer to function value
5952 being invoked. The argument types must match the types implied by this
5953 signature. This type can be omitted if the function is not varargs and if
5954 the function type does not return a pointer to a function.</li>
5955
5956 <li>'<tt>fnptrval</tt>': An LLVM value containing a pointer to a function to
5957 be invoked. In most cases, this is a direct function invocation, but
5958 indirect <tt>call</tt>s are just as possible, calling an arbitrary pointer
5959 to function value.</li>
5960
5961 <li>'<tt>function args</tt>': argument list whose types match the function
Chris Lattner47f2a832010-03-02 06:36:51 +0000[diff] [blame]5962 signature argument types and parameter attributes. All arguments must be
5963 of <a href="#t_firstclass">first class</a> type. If the function
5964 signature indicates the function accepts a variable number of arguments,
5965 the extra arguments can be specified.</li>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5966
5967 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
5968 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
5969 '<tt>readnone</tt>' attributes are valid here.</li>
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]5970</ol>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5971
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]5972<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5973<p>The '<tt>call</tt>' instruction is used to cause control flow to transfer to
5974 a specified function, with its incoming arguments bound to the specified
5975 values. Upon a '<tt><a href="#i_ret">ret</a></tt>' instruction in the called
5976 function, control flow continues with the instruction after the function
5977 call, and the return value of the function is bound to the result
5978 argument.</p>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5979
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]5980<h5>Example:</h5>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5981<pre>
Nick Lewyckya9b13d52007-09-08 13:57:50 +0000[diff] [blame]5982 %retval = call i32 @test(i32 %argc)
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]5983 call i32 (i8*, ...)* @printf(i8* %msg, i32 12, i8 42) <i>; yields i32</i>
Chris Lattnerfb7c88d2008-03-21 17:24:17 +0000[diff] [blame]5984 %X = tail call i32 @foo() <i>; yields i32</i>
5985 %Y = tail call <a href="#callingconv">fastcc</a> i32 @foo() <i>; yields i32</i>
5986 call void %foo(i8 97 signext)
Devang Pateld6cff512008-03-10 20:49:15 +0000[diff] [blame]5987
5988 %struct.A = type { i32, i8 }
Devang Patel7e9b05e2008-10-06 18:50:38 +0000[diff] [blame]5989 %r = call %struct.A @foo() <i>; yields { 32, i8 }</i>
Dan Gohmancc3132e2008-10-04 19:00:07 +0000[diff] [blame]5990 %gr = extractvalue %struct.A %r, 0 <i>; yields i32</i>
5991 %gr1 = extractvalue %struct.A %r, 1 <i>; yields i8</i>
Chris Lattner6cbe8e92008-10-08 06:26:11 +0000[diff] [blame]5992 %Z = call void @foo() noreturn <i>; indicates that %foo never returns normally</i>
Matthijs Kooijmaneefa7df2008-10-07 10:03:45 +0000[diff] [blame]5993 %ZZ = call zeroext i32 @bar() <i>; Return value is %zero extended</i>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5994</pre>
5995
Dale Johannesen68f971b2009-09-24 18:38:21 +0000[diff] [blame]5996<p>llvm treats calls to some functions with names and arguments that match the
Dale Johannesen722212d2009-09-25 17:04:42 +0000[diff] [blame]5997standard C99 library as being the C99 library functions, and may perform
5998optimizations or generate code for them under that assumption. This is
5999something we'd like to change in the future to provide better support for
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]6000freestanding environments and non-C-based languages.</p>
Dale Johannesen68f971b2009-09-24 18:38:21 +0000[diff] [blame]6001
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]6002</div>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]6003
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]6004<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6005<h4>
Chris Lattner33337472006-01-13 23:26:01 +0000[diff] [blame]6006 <a name="i_va_arg">'<tt>va_arg</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6007</h4>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]6008
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6009<div>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]6010
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]6011<h5>Syntax:</h5>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]6012<pre>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]6013 &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]6014</pre>
6015
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]6016<h5>Overview:</h5>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]6017<p>The '<tt>va_arg</tt>' instruction is used to access arguments passed through
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6018 the "variable argument" area of a function call. It is used to implement the
6019 <tt>va_arg</tt> macro in C.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]6020
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]6021<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6022<p>This instruction takes a <tt>va_list*</tt> value and the type of the
6023 argument. It returns a value of the specified argument type and increments
6024 the <tt>va_list</tt> to point to the next argument. The actual type
6025 of <tt>va_list</tt> is target specific.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]6026
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]6027<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6028<p>The '<tt>va_arg</tt>' instruction loads an argument of the specified type
6029 from the specified <tt>va_list</tt> and causes the <tt>va_list</tt> to point
6030 to the next argument. For more information, see the variable argument
6031 handling <a href="#int_varargs">Intrinsic Functions</a>.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]6032
6033<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]6034 take a variable number of arguments, for example, the <tt>vfprintf</tt>
6035 function.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]6036
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6037<p><tt>va_arg</tt> is an LLVM instruction instead of
6038 an <a href="#intrinsics">intrinsic function</a> because it takes a type as an
6039 argument.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]6040
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]6041<h5>Example:</h5>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]6042<p>See the <a href="#int_varargs">variable argument processing</a> section.</p>
6043
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6044<p>Note that the code generator does not yet fully support va_arg on many
6045 targets. Also, it does not currently support va_arg with aggregate types on
6046 any target.</p>
Dan Gohman3065b612009-01-12 23:12:39 +0000[diff] [blame]6047
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]6048</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]6049
Bill Wendlingbbcb7cd2011-08-02 21:52:38 +0000[diff] [blame]6050<!-- _______________________________________________________________________ -->
6051<h4>
6052 <a name="i_landingpad">'<tt>landingpad</tt>' Instruction</a>
6053</h4>
6054
6055<div>
6056
6057<h5>Syntax:</h5>
6058<pre>
Bill Wendling49bfb122011-08-08 08:06:05 +0000[diff] [blame]6059 &lt;resultval&gt; = landingpad &lt;somety&gt; personality &lt;type&gt; &lt;pers_fn&gt; &lt;clause&gt;+
6060 &lt;resultval&gt; = landingpad &lt;somety&gt; personality &lt;type&gt; &lt;pers_fn&gt; cleanup &lt;clause&gt;*
6061
Bill Wendlingbbcb7cd2011-08-02 21:52:38 +0000[diff] [blame]6062 &lt;clause&gt; := catch &lt;type&gt; &lt;value&gt;
Bill Wendlingfae14752011-08-12 20:24:12 +0000[diff] [blame]6063 &lt;clause&gt; := filter &lt;array constant type&gt; &lt;array constant&gt;
Bill Wendlingbbcb7cd2011-08-02 21:52:38 +0000[diff] [blame]6064</pre>
6065
6066<h5>Overview:</h5>
6067<p>The '<tt>landingpad</tt>' instruction is used by
6068 <a href="ExceptionHandling.html#overview">LLVM's exception handling
6069 system</a> to specify that a basic block is a landing pad &mdash; one where
6070 the exception lands, and corresponds to the code found in the
6071 <i><tt>catch</tt></i> portion of a <i><tt>try/catch</tt></i> sequence. It
6072 defines values supplied by the personality function (<tt>pers_fn</tt>) upon
6073 re-entry to the function. The <tt>resultval</tt> has the
6074 type <tt>somety</tt>.</p>
6075
6076<h5>Arguments:</h5>
6077<p>This instruction takes a <tt>pers_fn</tt> value. This is the personality
6078 function associated with the unwinding mechanism. The optional
6079 <tt>cleanup</tt> flag indicates that the landing pad block is a cleanup.</p>
6080
6081<p>A <tt>clause</tt> begins with the clause type &mdash; <tt>catch</tt>
Bill Wendlingfae14752011-08-12 20:24:12 +0000[diff] [blame]6082 or <tt>filter</tt> &mdash; and contains the global variable representing the
6083 "type" that may be caught or filtered respectively. Unlike the
6084 <tt>catch</tt> clause, the <tt>filter</tt> clause takes an array constant as
6085 its argument. Use "<tt>[0 x i8**] undef</tt>" for a filter which cannot
6086 throw. The '<tt>landingpad</tt>' instruction must contain <em>at least</em>
Bill Wendlingbbcb7cd2011-08-02 21:52:38 +0000[diff] [blame]6087 one <tt>clause</tt> or the <tt>cleanup</tt> flag.</p>
6088
6089<h5>Semantics:</h5>
6090<p>The '<tt>landingpad</tt>' instruction defines the values which are set by the
6091 personality function (<tt>pers_fn</tt>) upon re-entry to the function, and
6092 therefore the "result type" of the <tt>landingpad</tt> instruction. As with
6093 calling conventions, how the personality function results are represented in
6094 LLVM IR is target specific.</p>
6095
Bill Wendling0524b8d2011-08-03 17:17:06 +0000[diff] [blame]6096<p>The clauses are applied in order from top to bottom. If two
6097 <tt>landingpad</tt> instructions are merged together through inlining, the
Bill Wendlinga503fc02011-08-08 07:58:58 +0000[diff] [blame]6098 clauses from the calling function are appended to the list of clauses.</p>
Bill Wendling0524b8d2011-08-03 17:17:06 +0000[diff] [blame]6099
Bill Wendlingbbcb7cd2011-08-02 21:52:38 +0000[diff] [blame]6100<p>The <tt>landingpad</tt> instruction has several restrictions:</p>
6101
6102<ul>
6103 <li>A landing pad block is a basic block which is the unwind destination of an
6104 '<tt>invoke</tt>' instruction.</li>
6105 <li>A landing pad block must have a '<tt>landingpad</tt>' instruction as its
6106 first non-PHI instruction.</li>
6107 <li>There can be only one '<tt>landingpad</tt>' instruction within the landing
6108 pad block.</li>
6109 <li>A basic block that is not a landing pad block may not include a
6110 '<tt>landingpad</tt>' instruction.</li>
6111 <li>All '<tt>landingpad</tt>' instructions in a function must have the same
6112 personality function.</li>
6113</ul>
6114
6115<h5>Example:</h5>
6116<pre>
6117 ;; A landing pad which can catch an integer.
6118 %res = landingpad { i8*, i32 } personality i32 (...)* @__gxx_personality_v0
6119 catch i8** @_ZTIi
6120 ;; A landing pad that is a cleanup.
6121 %res = landingpad { i8*, i32 } personality i32 (...)* @__gxx_personality_v0
Bill Wendlingfae14752011-08-12 20:24:12 +0000[diff] [blame]6122 cleanup
Bill Wendlingbbcb7cd2011-08-02 21:52:38 +0000[diff] [blame]6123 ;; A landing pad which can catch an integer and can only throw a double.
6124 %res = landingpad { i8*, i32 } personality i32 (...)* @__gxx_personality_v0
6125 catch i8** @_ZTIi
Bill Wendlingfae14752011-08-12 20:24:12 +0000[diff] [blame]6126 filter [1 x i8**] [@_ZTId]
Bill Wendlingbbcb7cd2011-08-02 21:52:38 +0000[diff] [blame]6127</pre>
6128
6129</div>
6130
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6131</div>
6132
6133</div>
6134
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]6135<!-- *********************************************************************** -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6136<h2><a name="intrinsics">Intrinsic Functions</a></h2>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]6137<!-- *********************************************************************** -->
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]6138
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6139<div>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6140
6141<p>LLVM supports the notion of an "intrinsic function". These functions have
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6142 well known names and semantics and are required to follow certain
6143 restrictions. Overall, these intrinsics represent an extension mechanism for
6144 the LLVM language that does not require changing all of the transformations
6145 in LLVM when adding to the language (or the bitcode reader/writer, the
6146 parser, etc...).</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6147
John Criswell88190562005-05-16 16:17:45 +0000[diff] [blame]6148<p>Intrinsic function names must all start with an "<tt>llvm.</tt>" prefix. This
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6149 prefix is reserved in LLVM for intrinsic names; thus, function names may not
6150 begin with this prefix. Intrinsic functions must always be external
6151 functions: you cannot define the body of intrinsic functions. Intrinsic
6152 functions may only be used in call or invoke instructions: it is illegal to
6153 take the address of an intrinsic function. Additionally, because intrinsic
6154 functions are part of the LLVM language, it is required if any are added that
6155 they be documented here.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6156
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6157<p>Some intrinsic functions can be overloaded, i.e., the intrinsic represents a
6158 family of functions that perform the same operation but on different data
6159 types. Because LLVM can represent over 8 million different integer types,
6160 overloading is used commonly to allow an intrinsic function to operate on any
6161 integer type. One or more of the argument types or the result type can be
6162 overloaded to accept any integer type. Argument types may also be defined as
6163 exactly matching a previous argument's type or the result type. This allows
6164 an intrinsic function which accepts multiple arguments, but needs all of them
6165 to be of the same type, to only be overloaded with respect to a single
6166 argument or the result.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6167
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6168<p>Overloaded intrinsics will have the names of its overloaded argument types
6169 encoded into its function name, each preceded by a period. Only those types
6170 which are overloaded result in a name suffix. Arguments whose type is matched
6171 against another type do not. For example, the <tt>llvm.ctpop</tt> function
6172 can take an integer of any width and returns an integer of exactly the same
6173 integer width. This leads to a family of functions such as
6174 <tt>i8 @llvm.ctpop.i8(i8 %val)</tt> and <tt>i29 @llvm.ctpop.i29(i29
6175 %val)</tt>. Only one type, the return type, is overloaded, and only one type
6176 suffix is required. Because the argument's type is matched against the return
6177 type, it does not require its own name suffix.</p>
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]6178
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]6179<p>To learn how to add an intrinsic function, please see the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6180 <a href="ExtendingLLVM.html">Extending LLVM Guide</a>.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6181
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]6182<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6183<h3>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]6184 <a name="int_varargs">Variable Argument Handling Intrinsics</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6185</h3>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]6186
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6187<div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6188
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6189<p>Variable argument support is defined in LLVM with
6190 the <a href="#i_va_arg"><tt>va_arg</tt></a> instruction and these three
6191 intrinsic functions. These functions are related to the similarly named
6192 macros defined in the <tt>&lt;stdarg.h&gt;</tt> header file.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6193
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6194<p>All of these functions operate on arguments that use a target-specific value
6195 type "<tt>va_list</tt>". The LLVM assembly language reference manual does
6196 not define what this type is, so all transformations should be prepared to
6197 handle these functions regardless of the type used.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6198
Chris Lattner30b868d2006-05-15 17:26:46 +0000[diff] [blame]6199<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]6200 instruction and the variable argument handling intrinsic functions are
6201 used.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6202
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]6203<pre class="doc_code">
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]6204define i32 @test(i32 %X, ...) {
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6205 ; Initialize variable argument processing
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]6206 %ap = alloca i8*
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]6207 %ap2 = bitcast i8** %ap to i8*
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]6208 call void @llvm.va_start(i8* %ap2)
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6209
6210 ; Read a single integer argument
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]6211 %tmp = va_arg i8** %ap, i32
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6212
6213 ; Demonstrate usage of llvm.va_copy and llvm.va_end
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]6214 %aq = alloca i8*
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]6215 %aq2 = bitcast i8** %aq to i8*
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]6216 call void @llvm.va_copy(i8* %aq2, i8* %ap2)
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]6217 call void @llvm.va_end(i8* %aq2)
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6218
6219 ; Stop processing of arguments.
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]6220 call void @llvm.va_end(i8* %ap2)
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]6221 ret i32 %tmp
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6222}
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]6223
6224declare void @llvm.va_start(i8*)
6225declare void @llvm.va_copy(i8*, i8*)
6226declare void @llvm.va_end(i8*)
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6227</pre>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]6228
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]6229<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6230<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6231 <a name="int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6232</h4>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]6233
6234
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6235<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6236
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]6237<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6238<pre>
6239 declare void %llvm.va_start(i8* &lt;arglist&gt;)
6240</pre>
6241
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]6242<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6243<p>The '<tt>llvm.va_start</tt>' intrinsic initializes <tt>*&lt;arglist&gt;</tt>
6244 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]6245
6246<h5>Arguments:</h5>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]6247<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]6248
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]6249<h5>Semantics:</h5>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]6250<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]6251 macro available in C. In a target-dependent way, it initializes
6252 the <tt>va_list</tt> element to which the argument points, so that the next
6253 call to <tt>va_arg</tt> will produce the first variable argument passed to
6254 the function. Unlike the C <tt>va_start</tt> macro, this intrinsic does not
6255 need to know the last argument of the function as the compiler can figure
6256 that out.</p>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]6257
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]6258</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]6259
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]6260<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6261<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6262 <a name="int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6263</h4>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]6264
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6265<div>
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]6266
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6267<h5>Syntax:</h5>
6268<pre>
6269 declare void @llvm.va_end(i8* &lt;arglist&gt;)
6270</pre>
6271
6272<h5>Overview:</h5>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]6273<p>The '<tt>llvm.va_end</tt>' intrinsic destroys <tt>*&lt;arglist&gt;</tt>,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6274 which has been initialized previously
6275 with <tt><a href="#int_va_start">llvm.va_start</a></tt>
6276 or <tt><a href="#i_va_copy">llvm.va_copy</a></tt>.</p>
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]6277
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]6278<h5>Arguments:</h5>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]6279<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]6280
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]6281<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]6282<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]6283 macro available in C. In a target-dependent way, it destroys
6284 the <tt>va_list</tt> element to which the argument points. Calls
6285 to <a href="#int_va_start"><tt>llvm.va_start</tt></a>
6286 and <a href="#int_va_copy"> <tt>llvm.va_copy</tt></a> must be matched exactly
6287 with calls to <tt>llvm.va_end</tt>.</p>
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]6288
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]6289</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]6290
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]6291<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6292<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6293 <a name="int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6294</h4>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]6295
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6296<div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6297
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]6298<h5>Syntax:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6299<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]6300 declare void @llvm.va_copy(i8* &lt;destarglist&gt;, i8* &lt;srcarglist&gt;)
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6301</pre>
6302
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]6303<h5>Overview:</h5>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]6304<p>The '<tt>llvm.va_copy</tt>' intrinsic copies the current argument position
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6305 from the source argument list to the destination argument list.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6306
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]6307<h5>Arguments:</h5>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]6308<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]6309 The second argument is a pointer to a <tt>va_list</tt> element to copy
6310 from.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6311
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]6312<h5>Semantics:</h5>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]6313<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]6314 macro available in C. In a target-dependent way, it copies the
6315 source <tt>va_list</tt> element into the destination <tt>va_list</tt>
6316 element. This intrinsic is necessary because
6317 the <tt><a href="#int_va_start"> llvm.va_start</a></tt> intrinsic may be
6318 arbitrarily complex and require, for example, memory allocation.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6319
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]6320</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]6321
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6322</div>
6323
Bill Wendling537603b2011-07-31 06:45:03 +0000[diff] [blame]6324</div>
6325
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6326<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6327<h3>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6328 <a name="int_gc">Accurate Garbage Collection Intrinsics</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6329</h3>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6330
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6331<div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6332
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6333<p>LLVM support for <a href="GarbageCollection.html">Accurate Garbage
Chris Lattner67c37d12008-08-05 18:29:16 +0000[diff] [blame]6334Collection</a> (GC) requires the implementation and generation of these
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6335intrinsics. These intrinsics allow identification of <a href="#int_gcroot">GC
6336roots on the stack</a>, as well as garbage collector implementations that
6337require <a href="#int_gcread">read</a> and <a href="#int_gcwrite">write</a>
6338barriers. Front-ends for type-safe garbage collected languages should generate
6339these intrinsics to make use of the LLVM garbage collectors. For more details,
6340see <a href="GarbageCollection.html">Accurate Garbage Collection with
6341LLVM</a>.</p>
Christopher Lamb55c6d4f2007-12-17 01:00:21 +0000[diff] [blame]6342
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6343<p>The garbage collection intrinsics only operate on objects in the generic
6344 address space (address space zero).</p>
Christopher Lamb55c6d4f2007-12-17 01:00:21 +0000[diff] [blame]6345
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6346<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6347<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6348 <a name="int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6349</h4>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6350
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6351<div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6352
6353<h5>Syntax:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6354<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]6355 declare void @llvm.gcroot(i8** %ptrloc, i8* %metadata)
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6356</pre>
6357
6358<h5>Overview:</h5>
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]6359<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]6360 the code generator, and allows some metadata to be associated with it.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6361
6362<h5>Arguments:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6363<p>The first argument specifies the address of a stack object that contains the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6364 root pointer. The second pointer (which must be either a constant or a
6365 global value address) contains the meta-data to be associated with the
6366 root.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6367
6368<h5>Semantics:</h5>
Chris Lattner851b7712008-04-24 05:59:56 +0000[diff] [blame]6369<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]6370 location. At compile-time, the code generator generates information to allow
6371 the runtime to find the pointer at GC safe points. The '<tt>llvm.gcroot</tt>'
6372 intrinsic may only be used in a function which <a href="#gc">specifies a GC
6373 algorithm</a>.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6374
6375</div>
6376
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6377<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6378<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6379 <a name="int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6380</h4>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6381
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6382<div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6383
6384<h5>Syntax:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6385<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]6386 declare i8* @llvm.gcread(i8* %ObjPtr, i8** %Ptr)
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6387</pre>
6388
6389<h5>Overview:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6390<p>The '<tt>llvm.gcread</tt>' intrinsic identifies reads of references from heap
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6391 locations, allowing garbage collector implementations that require read
6392 barriers.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6393
6394<h5>Arguments:</h5>
Chris Lattnerf9228072006-03-14 20:02:51 +0000[diff] [blame]6395<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]6396 allocated from the garbage collector. The first object is a pointer to the
6397 start of the referenced object, if needed by the language runtime (otherwise
6398 null).</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6399
6400<h5>Semantics:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6401<p>The '<tt>llvm.gcread</tt>' intrinsic has the same semantics as a load
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6402 instruction, but may be replaced with substantially more complex code by the
6403 garbage collector runtime, as needed. The '<tt>llvm.gcread</tt>' intrinsic
6404 may only be used in a function which <a href="#gc">specifies a GC
6405 algorithm</a>.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6406
6407</div>
6408
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6409<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6410<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6411 <a name="int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6412</h4>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6413
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6414<div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6415
6416<h5>Syntax:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6417<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]6418 declare void @llvm.gcwrite(i8* %P1, i8* %Obj, i8** %P2)
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6419</pre>
6420
6421<h5>Overview:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6422<p>The '<tt>llvm.gcwrite</tt>' intrinsic identifies writes of references to heap
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6423 locations, allowing garbage collector implementations that require write
6424 barriers (such as generational or reference counting collectors).</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6425
6426<h5>Arguments:</h5>
Chris Lattnerf9228072006-03-14 20:02:51 +0000[diff] [blame]6427<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]6428 object to store it to, and the third is the address of the field of Obj to
6429 store to. If the runtime does not require a pointer to the object, Obj may
6430 be null.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6431
6432<h5>Semantics:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6433<p>The '<tt>llvm.gcwrite</tt>' intrinsic has the same semantics as a store
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6434 instruction, but may be replaced with substantially more complex code by the
6435 garbage collector runtime, as needed. The '<tt>llvm.gcwrite</tt>' intrinsic
6436 may only be used in a function which <a href="#gc">specifies a GC
6437 algorithm</a>.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6438
6439</div>
6440
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6441</div>
6442
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6443<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6444<h3>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6445 <a name="int_codegen">Code Generator Intrinsics</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6446</h3>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6447
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6448<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6449
6450<p>These intrinsics are provided by LLVM to expose special features that may
6451 only be implemented with code generator support.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6452
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6453<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6454<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6455 <a name="int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6456</h4>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6457
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6458<div>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6459
6460<h5>Syntax:</h5>
6461<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]6462 declare i8 *@llvm.returnaddress(i32 &lt;level&gt;)
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6463</pre>
6464
6465<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6466<p>The '<tt>llvm.returnaddress</tt>' intrinsic attempts to compute a
6467 target-specific value indicating the return address of the current function
6468 or one of its callers.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6469
6470<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6471<p>The argument to this intrinsic indicates which function to return the address
6472 for. Zero indicates the calling function, one indicates its caller, etc.
6473 The argument is <b>required</b> to be a constant integer value.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6474
6475<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6476<p>The '<tt>llvm.returnaddress</tt>' intrinsic either returns a pointer
6477 indicating the return address of the specified call frame, or zero if it
6478 cannot be identified. The value returned by this intrinsic is likely to be
6479 incorrect or 0 for arguments other than zero, so it should only be used for
6480 debugging purposes.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6481
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6482<p>Note that calling this intrinsic does not prevent function inlining or other
6483 aggressive transformations, so the value returned may not be that of the
6484 obvious source-language caller.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6485
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6486</div>
6487
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6488<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6489<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6490 <a name="int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6491</h4>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6492
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6493<div>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6494
6495<h5>Syntax:</h5>
6496<pre>
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]6497 declare i8* @llvm.frameaddress(i32 &lt;level&gt;)
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6498</pre>
6499
6500<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6501<p>The '<tt>llvm.frameaddress</tt>' intrinsic attempts to return the
6502 target-specific frame pointer value for the specified stack frame.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6503
6504<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6505<p>The argument to this intrinsic indicates which function to return the frame
6506 pointer for. Zero indicates the calling function, one indicates its caller,
6507 etc. The argument is <b>required</b> to be a constant integer value.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6508
6509<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6510<p>The '<tt>llvm.frameaddress</tt>' intrinsic either returns a pointer
6511 indicating the frame address of the specified call frame, or zero if it
6512 cannot be identified. The value returned by this intrinsic is likely to be
6513 incorrect or 0 for arguments other than zero, so it should only be used for
6514 debugging purposes.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6515
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6516<p>Note that calling this intrinsic does not prevent function inlining or other
6517 aggressive transformations, so the value returned may not be that of the
6518 obvious source-language caller.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6519
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6520</div>
6521
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]6522<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6523<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6524 <a name="int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6525</h4>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]6526
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6527<div>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]6528
6529<h5>Syntax:</h5>
6530<pre>
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]6531 declare i8* @llvm.stacksave()
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]6532</pre>
6533
6534<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6535<p>The '<tt>llvm.stacksave</tt>' intrinsic is used to remember the current state
6536 of the function stack, for use
6537 with <a href="#int_stackrestore"> <tt>llvm.stackrestore</tt></a>. This is
6538 useful for implementing language features like scoped automatic variable
6539 sized arrays in C99.</p>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]6540
6541<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6542<p>This intrinsic returns a opaque pointer value that can be passed
6543 to <a href="#int_stackrestore"><tt>llvm.stackrestore</tt></a>. When
6544 an <tt>llvm.stackrestore</tt> intrinsic is executed with a value saved
6545 from <tt>llvm.stacksave</tt>, it effectively restores the state of the stack
6546 to the state it was in when the <tt>llvm.stacksave</tt> intrinsic executed.
6547 In practice, this pops any <a href="#i_alloca">alloca</a> blocks from the
6548 stack that were allocated after the <tt>llvm.stacksave</tt> was executed.</p>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]6549
6550</div>
6551
6552<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6553<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6554 <a name="int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6555</h4>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]6556
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6557<div>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]6558
6559<h5>Syntax:</h5>
6560<pre>
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]6561 declare void @llvm.stackrestore(i8* %ptr)
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]6562</pre>
6563
6564<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6565<p>The '<tt>llvm.stackrestore</tt>' intrinsic is used to restore the state of
6566 the function stack to the state it was in when the
6567 corresponding <a href="#int_stacksave"><tt>llvm.stacksave</tt></a> intrinsic
6568 executed. This is useful for implementing language features like scoped
6569 automatic variable sized arrays in C99.</p>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]6570
6571<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6572<p>See the description
6573 for <a href="#int_stacksave"><tt>llvm.stacksave</tt></a>.</p>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]6574
6575</div>
6576
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]6577<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6578<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6579 <a name="int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6580</h4>
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]6581
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6582<div>
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]6583
6584<h5>Syntax:</h5>
6585<pre>
Bruno Cardoso Lopesdc9ff3a2011-06-14 04:58:37 +0000[diff] [blame]6586 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]6587</pre>
6588
6589<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6590<p>The '<tt>llvm.prefetch</tt>' intrinsic is a hint to the code generator to
6591 insert a prefetch instruction if supported; otherwise, it is a noop.
6592 Prefetches have no effect on the behavior of the program but can change its
6593 performance characteristics.</p>
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]6594
6595<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6596<p><tt>address</tt> is the address to be prefetched, <tt>rw</tt> is the
6597 specifier determining if the fetch should be for a read (0) or write (1),
6598 and <tt>locality</tt> is a temporal locality specifier ranging from (0) - no
Bruno Cardoso Lopesdc9ff3a2011-06-14 04:58:37 +0000[diff] [blame]6599 locality, to (3) - extremely local keep in cache. The <tt>cache type</tt>
6600 specifies whether the prefetch is performed on the data (1) or instruction (0)
6601 cache. The <tt>rw</tt>, <tt>locality</tt> and <tt>cache type</tt> arguments
6602 must be constant integers.</p>
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]6603
6604<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6605<p>This intrinsic does not modify the behavior of the program. In particular,
6606 prefetches cannot trap and do not produce a value. On targets that support
6607 this intrinsic, the prefetch can provide hints to the processor cache for
6608 better performance.</p>
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]6609
6610</div>
6611
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]6612<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6613<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6614 <a name="int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6615</h4>
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]6616
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6617<div>
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]6618
6619<h5>Syntax:</h5>
6620<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]6621 declare void @llvm.pcmarker(i32 &lt;id&gt;)
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]6622</pre>
6623
6624<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6625<p>The '<tt>llvm.pcmarker</tt>' intrinsic is a method to export a Program
6626 Counter (PC) in a region of code to simulators and other tools. The method
6627 is target specific, but it is expected that the marker will use exported
6628 symbols to transmit the PC of the marker. The marker makes no guarantees
6629 that it will remain with any specific instruction after optimizations. It is
6630 possible that the presence of a marker will inhibit optimizations. The
6631 intended use is to be inserted after optimizations to allow correlations of
6632 simulation runs.</p>
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]6633
6634<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6635<p><tt>id</tt> is a numerical id identifying the marker.</p>
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]6636
6637<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6638<p>This intrinsic does not modify the behavior of the program. Backends that do
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]6639 not support this intrinsic may ignore it.</p>
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]6640
6641</div>
6642
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]6643<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6644<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6645 <a name="int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6646</h4>
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]6647
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6648<div>
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]6649
6650<h5>Syntax:</h5>
6651<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]6652 declare i64 @llvm.readcyclecounter()
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]6653</pre>
6654
6655<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6656<p>The '<tt>llvm.readcyclecounter</tt>' intrinsic provides access to the cycle
6657 counter register (or similar low latency, high accuracy clocks) on those
6658 targets that support it. On X86, it should map to RDTSC. On Alpha, it
6659 should map to RPCC. As the backing counters overflow quickly (on the order
6660 of 9 seconds on alpha), this should only be used for small timings.</p>
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]6661
6662<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6663<p>When directly supported, reading the cycle counter should not modify any
6664 memory. Implementations are allowed to either return a application specific
6665 value or a system wide value. On backends without support, this is lowered
6666 to a constant 0.</p>
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]6667
6668</div>
6669
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6670</div>
6671
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6672<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6673<h3>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6674 <a name="int_libc">Standard C Library Intrinsics</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6675</h3>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6676
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6677<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6678
6679<p>LLVM provides intrinsics for a few important standard C library functions.
6680 These intrinsics allow source-language front-ends to pass information about
6681 the alignment of the pointer arguments to the code generator, providing
6682 opportunity for more efficient code generation.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6683
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6684<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6685<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6686 <a name="int_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6687</h4>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6688
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6689<div>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6690
6691<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6692<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]6693 integer bit width and for different address spaces. Not all targets support
6694 all bit widths however.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6695
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6696<pre>
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]6697 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]6698 i32 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]6699 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]6700 i64 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6701</pre>
6702
6703<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6704<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
6705 source location to the destination location.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6706
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6707<p>Note that, unlike the standard libc function, the <tt>llvm.memcpy.*</tt>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6708 intrinsics do not return a value, takes extra alignment/isvolatile arguments
6709 and the pointers can be in specified address spaces.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6710
6711<h5>Arguments:</h5>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6712
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6713<p>The first argument is a pointer to the destination, the second is a pointer
6714 to the source. The third argument is an integer argument specifying the
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6715 number of bytes to copy, the fourth argument is the alignment of the
6716 source and destination locations, and the fifth is a boolean indicating a
6717 volatile access.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6718
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]6719<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]6720 then the caller guarantees that both the source and destination pointers are
6721 aligned to that boundary.</p>
Chris Lattner4c67c482004-02-12 21:18:15 +0000[diff] [blame]6722
Jeffrey Yasskin5d284ae2010-04-26 21:21:24 +0000[diff] [blame]6723<p>If the <tt>isvolatile</tt> parameter is <tt>true</tt>, the
6724 <tt>llvm.memcpy</tt> call is a <a href="#volatile">volatile operation</a>.
6725 The detailed access behavior is not very cleanly specified and it is unwise
6726 to depend on it.</p>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6727
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6728<h5>Semantics:</h5>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6729
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6730<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
6731 source location to the destination location, which are not allowed to
6732 overlap. It copies "len" bytes of memory over. If the argument is known to
6733 be aligned to some boundary, this can be specified as the fourth argument,
6734 otherwise it should be set to 0 or 1.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6735
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6736</div>
6737
Chris Lattnerf30152e2004-02-12 18:10:10 +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_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6741</h4>
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6742
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6743<div>
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6744
6745<h5>Syntax:</h5>
Chris Lattnerdd708342008-11-21 16:42:48 +0000[diff] [blame]6746<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]6747 width and for different address space. Not all targets support all bit
6748 widths however.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6749
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6750<pre>
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]6751 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]6752 i32 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]6753 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]6754 i64 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6755</pre>
6756
6757<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6758<p>The '<tt>llvm.memmove.*</tt>' intrinsics move a block of memory from the
6759 source location to the destination location. It is similar to the
6760 '<tt>llvm.memcpy</tt>' intrinsic but allows the two memory locations to
6761 overlap.</p>
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6762
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6763<p>Note that, unlike the standard libc function, the <tt>llvm.memmove.*</tt>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6764 intrinsics do not return a value, takes extra alignment/isvolatile arguments
6765 and the pointers can be in specified address spaces.</p>
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6766
6767<h5>Arguments:</h5>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6768
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6769<p>The first argument is a pointer to the destination, the second is a pointer
6770 to the source. The third argument is an integer argument specifying the
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6771 number of bytes to copy, the fourth argument is the alignment of the
6772 source and destination locations, and the fifth is a boolean indicating a
6773 volatile access.</p>
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6774
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]6775<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]6776 then the caller guarantees that the source and destination pointers are
6777 aligned to that boundary.</p>
Chris Lattner4c67c482004-02-12 21:18:15 +0000[diff] [blame]6778
Jeffrey Yasskin5d284ae2010-04-26 21:21:24 +0000[diff] [blame]6779<p>If the <tt>isvolatile</tt> parameter is <tt>true</tt>, the
6780 <tt>llvm.memmove</tt> call is a <a href="#volatile">volatile operation</a>.
6781 The detailed access behavior is not very cleanly specified and it is unwise
6782 to depend on it.</p>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6783
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6784<h5>Semantics:</h5>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6785
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6786<p>The '<tt>llvm.memmove.*</tt>' intrinsics copy a block of memory from the
6787 source location to the destination location, which may overlap. It copies
6788 "len" bytes of memory over. If the argument is known to be aligned to some
6789 boundary, this can be specified as the fourth argument, otherwise it should
6790 be set to 0 or 1.</p>
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6791
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6792</div>
6793
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6794<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6795<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6796 <a name="int_memset">'<tt>llvm.memset.*</tt>' Intrinsics</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6797</h4>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6798
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6799<div>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6800
6801<h5>Syntax:</h5>
Chris Lattnerdd708342008-11-21 16:42:48 +0000[diff] [blame]6802<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]6803 width and for different address spaces. However, not all targets support all
6804 bit widths.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6805
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6806<pre>
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]6807 declare void @llvm.memset.p0i8.i32(i8* &lt;dest&gt;, i8 &lt;val&gt;,
Chris Lattner685db9d2010-04-08 00:54:34 +0000[diff] [blame]6808 i32 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]6809 declare void @llvm.memset.p0i8.i64(i8* &lt;dest&gt;, i8 &lt;val&gt;,
Chris Lattner685db9d2010-04-08 00:54:34 +0000[diff] [blame]6810 i64 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6811</pre>
6812
6813<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6814<p>The '<tt>llvm.memset.*</tt>' intrinsics fill a block of memory with a
6815 particular byte value.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6816
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6817<p>Note that, unlike the standard libc function, the <tt>llvm.memset</tt>
John Criswellad05ae42010-07-30 16:30:28 +0000[diff] [blame]6818 intrinsic does not return a value and takes extra alignment/volatile
6819 arguments. Also, the destination can be in an arbitrary address space.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6820
6821<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6822<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]6823 byte value with which to fill it, the third argument is an integer argument
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6824 specifying the number of bytes to fill, and the fourth argument is the known
John Criswellad05ae42010-07-30 16:30:28 +0000[diff] [blame]6825 alignment of the destination location.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6826
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]6827<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]6828 then the caller guarantees that the destination pointer is aligned to that
6829 boundary.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6830
Jeffrey Yasskin5d284ae2010-04-26 21:21:24 +0000[diff] [blame]6831<p>If the <tt>isvolatile</tt> parameter is <tt>true</tt>, the
6832 <tt>llvm.memset</tt> call is a <a href="#volatile">volatile operation</a>.
6833 The detailed access behavior is not very cleanly specified and it is unwise
6834 to depend on it.</p>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6835
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6836<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6837<p>The '<tt>llvm.memset.*</tt>' intrinsics fill "len" bytes of memory starting
6838 at the destination location. If the argument is known to be aligned to some
6839 boundary, this can be specified as the fourth argument, otherwise it should
6840 be set to 0 or 1.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6841
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6842</div>
6843
Chris Lattner3b4f4372004-06-11 02:28:03 +0000[diff] [blame]6844<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6845<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6846 <a name="int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6847</h4>
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]6848
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6849<div>
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]6850
6851<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6852<p>This is an overloaded intrinsic. You can use <tt>llvm.sqrt</tt> on any
6853 floating point or vector of floating point type. Not all targets support all
6854 types however.</p>
6855
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]6856<pre>
Dale Johannesendd89d272007-10-02 17:47:38 +0000[diff] [blame]6857 declare float @llvm.sqrt.f32(float %Val)
6858 declare double @llvm.sqrt.f64(double %Val)
6859 declare x86_fp80 @llvm.sqrt.f80(x86_fp80 %Val)
6860 declare fp128 @llvm.sqrt.f128(fp128 %Val)
6861 declare ppc_fp128 @llvm.sqrt.ppcf128(ppc_fp128 %Val)
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]6862</pre>
6863
6864<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6865<p>The '<tt>llvm.sqrt</tt>' intrinsics return the sqrt of the specified operand,
6866 returning the same value as the libm '<tt>sqrt</tt>' functions would.
6867 Unlike <tt>sqrt</tt> in libm, however, <tt>llvm.sqrt</tt> has undefined
6868 behavior for negative numbers other than -0.0 (which allows for better
6869 optimization, because there is no need to worry about errno being
6870 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]6871
6872<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6873<p>The argument and return value are floating point numbers of the same
6874 type.</p>
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]6875
6876<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6877<p>This function returns the sqrt of the specified operand if it is a
6878 nonnegative floating point number.</p>
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]6879
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]6880</div>
6881
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]6882<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6883<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6884 <a name="int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6885</h4>
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]6886
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6887<div>
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]6888
6889<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6890<p>This is an overloaded intrinsic. You can use <tt>llvm.powi</tt> on any
6891 floating point or vector of floating point type. Not all targets support all
6892 types however.</p>
6893
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]6894<pre>
Dale Johannesendd89d272007-10-02 17:47:38 +0000[diff] [blame]6895 declare float @llvm.powi.f32(float %Val, i32 %power)
6896 declare double @llvm.powi.f64(double %Val, i32 %power)
6897 declare x86_fp80 @llvm.powi.f80(x86_fp80 %Val, i32 %power)
6898 declare fp128 @llvm.powi.f128(fp128 %Val, i32 %power)
6899 declare ppc_fp128 @llvm.powi.ppcf128(ppc_fp128 %Val, i32 %power)
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]6900</pre>
6901
6902<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6903<p>The '<tt>llvm.powi.*</tt>' intrinsics return the first operand raised to the
6904 specified (positive or negative) power. The order of evaluation of
6905 multiplications is not defined. When a vector of floating point type is
6906 used, the second argument remains a scalar integer value.</p>
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]6907
6908<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6909<p>The second argument is an integer power, and the first is a value to raise to
6910 that power.</p>
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]6911
6912<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6913<p>This function returns the first value raised to the second power with an
6914 unspecified sequence of rounding operations.</p>
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]6915
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]6916</div>
6917
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6918<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6919<h4>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6920 <a name="int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6921</h4>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6922
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6923<div>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6924
6925<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6926<p>This is an overloaded intrinsic. You can use <tt>llvm.sin</tt> on any
6927 floating point or vector of floating point type. Not all targets support all
6928 types however.</p>
6929
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6930<pre>
6931 declare float @llvm.sin.f32(float %Val)
6932 declare double @llvm.sin.f64(double %Val)
6933 declare x86_fp80 @llvm.sin.f80(x86_fp80 %Val)
6934 declare fp128 @llvm.sin.f128(fp128 %Val)
6935 declare ppc_fp128 @llvm.sin.ppcf128(ppc_fp128 %Val)
6936</pre>
6937
6938<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6939<p>The '<tt>llvm.sin.*</tt>' intrinsics return the sine of the operand.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6940
6941<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6942<p>The argument and return value are floating point numbers of the same
6943 type.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6944
6945<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6946<p>This function returns the sine of the specified operand, returning the same
6947 values as the libm <tt>sin</tt> functions would, and handles error conditions
6948 in the same way.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6949
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6950</div>
6951
6952<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6953<h4>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6954 <a name="int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6955</h4>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6956
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6957<div>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6958
6959<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6960<p>This is an overloaded intrinsic. You can use <tt>llvm.cos</tt> on any
6961 floating point or vector of floating point type. Not all targets support all
6962 types however.</p>
6963
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6964<pre>
6965 declare float @llvm.cos.f32(float %Val)
6966 declare double @llvm.cos.f64(double %Val)
6967 declare x86_fp80 @llvm.cos.f80(x86_fp80 %Val)
6968 declare fp128 @llvm.cos.f128(fp128 %Val)
6969 declare ppc_fp128 @llvm.cos.ppcf128(ppc_fp128 %Val)
6970</pre>
6971
6972<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6973<p>The '<tt>llvm.cos.*</tt>' intrinsics return the cosine of the operand.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6974
6975<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6976<p>The argument and return value are floating point numbers of the same
6977 type.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6978
6979<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6980<p>This function returns the cosine of the specified operand, returning the same
6981 values as the libm <tt>cos</tt> functions would, and handles error conditions
6982 in the same way.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6983
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6984</div>
6985
6986<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6987<h4>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6988 <a name="int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6989</h4>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6990
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6991<div>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6992
6993<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6994<p>This is an overloaded intrinsic. You can use <tt>llvm.pow</tt> on any
6995 floating point or vector of floating point type. Not all targets support all
6996 types however.</p>
6997
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6998<pre>
6999 declare float @llvm.pow.f32(float %Val, float %Power)
7000 declare double @llvm.pow.f64(double %Val, double %Power)
7001 declare x86_fp80 @llvm.pow.f80(x86_fp80 %Val, x86_fp80 %Power)
7002 declare fp128 @llvm.pow.f128(fp128 %Val, fp128 %Power)
7003 declare ppc_fp128 @llvm.pow.ppcf128(ppc_fp128 %Val, ppc_fp128 Power)
7004</pre>
7005
7006<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7007<p>The '<tt>llvm.pow.*</tt>' intrinsics return the first operand raised to the
7008 specified (positive or negative) power.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]7009
7010<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7011<p>The second argument is a floating point power, and the first is a value to
7012 raise to that power.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]7013
7014<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7015<p>This function returns the first value raised to the second power, returning
7016 the same values as the libm <tt>pow</tt> functions would, and handles error
7017 conditions in the same way.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]7018
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]7019</div>
7020
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7021</div>
7022
Dan Gohman911fa902011-05-23 21:13:03 +0000[diff] [blame]7023<!-- _______________________________________________________________________ -->
7024<h4>
7025 <a name="int_exp">'<tt>llvm.exp.*</tt>' Intrinsic</a>
7026</h4>
7027
7028<div>
7029
7030<h5>Syntax:</h5>
7031<p>This is an overloaded intrinsic. You can use <tt>llvm.exp</tt> on any
7032 floating point or vector of floating point type. Not all targets support all
7033 types however.</p>
7034
7035<pre>
7036 declare float @llvm.exp.f32(float %Val)
7037 declare double @llvm.exp.f64(double %Val)
7038 declare x86_fp80 @llvm.exp.f80(x86_fp80 %Val)
7039 declare fp128 @llvm.exp.f128(fp128 %Val)
7040 declare ppc_fp128 @llvm.exp.ppcf128(ppc_fp128 %Val)
7041</pre>
7042
7043<h5>Overview:</h5>
7044<p>The '<tt>llvm.exp.*</tt>' intrinsics perform the exp function.</p>
7045
7046<h5>Arguments:</h5>
7047<p>The argument and return value are floating point numbers of the same
7048 type.</p>
7049
7050<h5>Semantics:</h5>
7051<p>This function returns the same values as the libm <tt>exp</tt> functions
7052 would, and handles error conditions in the same way.</p>
7053
7054</div>
7055
7056<!-- _______________________________________________________________________ -->
7057<h4>
7058 <a name="int_log">'<tt>llvm.log.*</tt>' Intrinsic</a>
7059</h4>
7060
7061<div>
7062
7063<h5>Syntax:</h5>
7064<p>This is an overloaded intrinsic. You can use <tt>llvm.log</tt> on any
7065 floating point or vector of floating point type. Not all targets support all
7066 types however.</p>
7067
7068<pre>
7069 declare float @llvm.log.f32(float %Val)
7070 declare double @llvm.log.f64(double %Val)
7071 declare x86_fp80 @llvm.log.f80(x86_fp80 %Val)
7072 declare fp128 @llvm.log.f128(fp128 %Val)
7073 declare ppc_fp128 @llvm.log.ppcf128(ppc_fp128 %Val)
7074</pre>
7075
7076<h5>Overview:</h5>
7077<p>The '<tt>llvm.log.*</tt>' intrinsics perform the log function.</p>
7078
7079<h5>Arguments:</h5>
7080<p>The argument and return value are floating point numbers of the same
7081 type.</p>
7082
7083<h5>Semantics:</h5>
7084<p>This function returns the same values as the libm <tt>log</tt> functions
7085 would, and handles error conditions in the same way.</p>
7086
Cameron Zwarichf03fa182011-07-08 21:39:21 +0000[diff] [blame]7087<h4>
7088 <a name="int_fma">'<tt>llvm.fma.*</tt>' Intrinsic</a>
7089</h4>
7090
7091<div>
7092
7093<h5>Syntax:</h5>
7094<p>This is an overloaded intrinsic. You can use <tt>llvm.fma</tt> on any
7095 floating point or vector of floating point type. Not all targets support all
7096 types however.</p>
7097
7098<pre>
7099 declare float @llvm.fma.f32(float %a, float %b, float %c)
7100 declare double @llvm.fma.f64(double %a, double %b, double %c)
7101 declare x86_fp80 @llvm.fma.f80(x86_fp80 %a, x86_fp80 %b, x86_fp80 %c)
7102 declare fp128 @llvm.fma.f128(fp128 %a, fp128 %b, fp128 %c)
7103 declare ppc_fp128 @llvm.fma.ppcf128(ppc_fp128 %a, ppc_fp128 %b, ppc_fp128 %c)
7104</pre>
7105
7106<h5>Overview:</h5>
Cameron Zwaricha32fd212011-07-08 22:13:55 +0000[diff] [blame]7107<p>The '<tt>llvm.fma.*</tt>' intrinsics perform the fused multiply-add
Cameron Zwarichf03fa182011-07-08 21:39:21 +0000[diff] [blame]7108 operation.</p>
7109
7110<h5>Arguments:</h5>
7111<p>The argument and return value are floating point numbers of the same
7112 type.</p>
7113
7114<h5>Semantics:</h5>
7115<p>This function returns the same values as the libm <tt>fma</tt> functions
7116 would.</p>
7117
Dan Gohman911fa902011-05-23 21:13:03 +0000[diff] [blame]7118</div>
7119
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7120<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7121<h3>
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]7122 <a name="int_manip">Bit Manipulation Intrinsics</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7123</h3>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7124
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7125<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7126
7127<p>LLVM provides intrinsics for a few important bit manipulation operations.
7128 These allow efficient code generation for some algorithms.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7129
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7130<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7131<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]7132 <a name="int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7133</h4>
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]7134
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7135<div>
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]7136
7137<h5>Syntax:</h5>
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]7138<p>This is an overloaded intrinsic function. You can use bswap on any integer
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7139 type that is an even number of bytes (i.e. BitWidth % 16 == 0).</p>
7140
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]7141<pre>
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]7142 declare i16 @llvm.bswap.i16(i16 &lt;id&gt;)
7143 declare i32 @llvm.bswap.i32(i32 &lt;id&gt;)
7144 declare i64 @llvm.bswap.i64(i64 &lt;id&gt;)
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]7145</pre>
7146
7147<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7148<p>The '<tt>llvm.bswap</tt>' family of intrinsics is used to byte swap integer
7149 values with an even number of bytes (positive multiple of 16 bits). These
7150 are useful for performing operations on data that is not in the target's
7151 native byte order.</p>
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]7152
7153<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7154<p>The <tt>llvm.bswap.i16</tt> intrinsic returns an i16 value that has the high
7155 and low byte of the input i16 swapped. Similarly,
7156 the <tt>llvm.bswap.i32</tt> intrinsic returns an i32 value that has the four
7157 bytes of the input i32 swapped, so that if the input bytes are numbered 0, 1,
7158 2, 3 then the returned i32 will have its bytes in 3, 2, 1, 0 order.
7159 The <tt>llvm.bswap.i48</tt>, <tt>llvm.bswap.i64</tt> and other intrinsics
7160 extend this concept to additional even-byte lengths (6 bytes, 8 bytes and
7161 more, respectively).</p>
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]7162
7163</div>
7164
7165<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7166<h4>
Reid Spencerb4f9a6f2006-01-16 21:12:35 +0000[diff] [blame]7167 <a name="int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7168</h4>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7169
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7170<div>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7171
7172<h5>Syntax:</h5>
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]7173<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]7174 width, or on any vector with integer elements. Not all targets support all
7175 bit widths or vector types, however.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7176
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7177<pre>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7178 declare i8 @llvm.ctpop.i8(i8 &lt;src&gt;)
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]7179 declare i16 @llvm.ctpop.i16(i16 &lt;src&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]7180 declare i32 @llvm.ctpop.i32(i32 &lt;src&gt;)
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]7181 declare i64 @llvm.ctpop.i64(i64 &lt;src&gt;)
7182 declare i256 @llvm.ctpop.i256(i256 &lt;src&gt;)
Owen Anderson2f37bdc2011-07-01 21:52:38 +0000[diff] [blame]7183 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]7184</pre>
7185
7186<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7187<p>The '<tt>llvm.ctpop</tt>' family of intrinsics counts the number of bits set
7188 in a value.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7189
7190<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7191<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]7192 integer type, or a vector with integer elements.
7193 The return type must match the argument type.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7194
7195<h5>Semantics:</h5>
Owen Anderson2f37bdc2011-07-01 21:52:38 +0000[diff] [blame]7196<p>The '<tt>llvm.ctpop</tt>' intrinsic counts the 1's in a variable, or within each
7197 element of a vector.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7198
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7199</div>
7200
7201<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7202<h4>
Chris Lattnerb748c672006-01-16 22:34:14 +0000[diff] [blame]7203 <a name="int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7204</h4>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7205
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7206<div>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7207
7208<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7209<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]7210 integer bit width, or any vector whose elements are integers. Not all
7211 targets support all bit widths or vector types, however.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7212
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7213<pre>
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]7214 declare i8 @llvm.ctlz.i8 (i8 &lt;src&gt;)
7215 declare i16 @llvm.ctlz.i16(i16 &lt;src&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]7216 declare i32 @llvm.ctlz.i32(i32 &lt;src&gt;)
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]7217 declare i64 @llvm.ctlz.i64(i64 &lt;src&gt;)
7218 declare i256 @llvm.ctlz.i256(i256 &lt;src&gt;)
Owen Anderson2f37bdc2011-07-01 21:52:38 +0000[diff] [blame]7219 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]7220</pre>
7221
7222<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7223<p>The '<tt>llvm.ctlz</tt>' family of intrinsic functions counts the number of
7224 leading zeros in a variable.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7225
7226<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7227<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]7228 integer type, or any vector type with integer element type.
7229 The return type must match the argument type.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7230
7231<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7232<p>The '<tt>llvm.ctlz</tt>' intrinsic counts the leading (most significant)
Owen Anderson2f37bdc2011-07-01 21:52:38 +0000[diff] [blame]7233 zeros in a variable, or within each element of the vector if the operation
7234 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]7235 the type of src. For example, <tt>llvm.ctlz(i32 2) = 30</tt>.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7236
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7237</div>
Chris Lattner3b4f4372004-06-11 02:28:03 +0000[diff] [blame]7238
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]7239<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7240<h4>
Chris Lattnerb748c672006-01-16 22:34:14 +0000[diff] [blame]7241 <a name="int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7242</h4>
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]7243
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7244<div>
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]7245
7246<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7247<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]7248 integer bit width, or any vector of integer elements. Not all targets
7249 support all bit widths or vector types, however.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7250
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]7251<pre>
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]7252 declare i8 @llvm.cttz.i8 (i8 &lt;src&gt;)
7253 declare i16 @llvm.cttz.i16(i16 &lt;src&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]7254 declare i32 @llvm.cttz.i32(i32 &lt;src&gt;)
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]7255 declare i64 @llvm.cttz.i64(i64 &lt;src&gt;)
7256 declare i256 @llvm.cttz.i256(i256 &lt;src&gt;)
Owen Anderson2f37bdc2011-07-01 21:52:38 +0000[diff] [blame]7257 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]7258</pre>
7259
7260<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7261<p>The '<tt>llvm.cttz</tt>' family of intrinsic functions counts the number of
7262 trailing zeros.</p>
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]7263
7264<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7265<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]7266 integer type, or a vectory with integer element type.. The return type
7267 must match the argument type.</p>
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]7268
7269<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7270<p>The '<tt>llvm.cttz</tt>' intrinsic counts the trailing (least significant)
Owen Anderson2f37bdc2011-07-01 21:52:38 +0000[diff] [blame]7271 zeros in a variable, or within each element of a vector.
7272 If the src == 0 then the result is the size in bits of
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7273 the type of src. For example, <tt>llvm.cttz(2) = 1</tt>.</p>
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]7274
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]7275</div>
7276
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7277</div>
7278
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]7279<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7280<h3>
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]7281 <a name="int_overflow">Arithmetic with Overflow Intrinsics</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7282</h3>
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]7283
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7284<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7285
7286<p>LLVM provides intrinsics for some arithmetic with overflow operations.</p>
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]7287
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7288<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7289<h4>
7290 <a name="int_sadd_overflow">
7291 '<tt>llvm.sadd.with.overflow.*</tt>' Intrinsics
7292 </a>
7293</h4>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7294
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7295<div>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7296
7297<h5>Syntax:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7298<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]7299 on any integer bit width.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7300
7301<pre>
7302 declare {i16, i1} @llvm.sadd.with.overflow.i16(i16 %a, i16 %b)
7303 declare {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
7304 declare {i64, i1} @llvm.sadd.with.overflow.i64(i64 %a, i64 %b)
7305</pre>
7306
7307<h5>Overview:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7308<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7309 a signed addition of the two arguments, and indicate whether an overflow
7310 occurred during the signed summation.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7311
7312<h5>Arguments:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7313<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]7314 be of integer types of any bit width, but they must have the same bit
7315 width. The second element of the result structure must be of
7316 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
7317 undergo signed addition.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7318
7319<h5>Semantics:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7320<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7321 a signed addition of the two variables. They return a structure &mdash; the
7322 first element of which is the signed summation, and the second element of
7323 which is a bit specifying if the signed summation resulted in an
7324 overflow.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7325
7326<h5>Examples:</h5>
7327<pre>
7328 %res = call {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
7329 %sum = extractvalue {i32, i1} %res, 0
7330 %obit = extractvalue {i32, i1} %res, 1
7331 br i1 %obit, label %overflow, label %normal
7332</pre>
7333
7334</div>
7335
7336<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7337<h4>
7338 <a name="int_uadd_overflow">
7339 '<tt>llvm.uadd.with.overflow.*</tt>' Intrinsics
7340 </a>
7341</h4>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7342
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7343<div>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7344
7345<h5>Syntax:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7346<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]7347 on any integer bit width.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7348
7349<pre>
7350 declare {i16, i1} @llvm.uadd.with.overflow.i16(i16 %a, i16 %b)
7351 declare {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
7352 declare {i64, i1} @llvm.uadd.with.overflow.i64(i64 %a, i64 %b)
7353</pre>
7354
7355<h5>Overview:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7356<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7357 an unsigned addition of the two arguments, and indicate whether a carry
7358 occurred during the unsigned summation.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7359
7360<h5>Arguments:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7361<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]7362 be of integer types of any bit width, but they must have the same bit
7363 width. The second element of the result structure must be of
7364 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
7365 undergo unsigned addition.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7366
7367<h5>Semantics:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7368<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7369 an unsigned addition of the two arguments. They return a structure &mdash;
7370 the first element of which is the sum, and the second element of which is a
7371 bit specifying if the unsigned summation resulted in a carry.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7372
7373<h5>Examples:</h5>
7374<pre>
7375 %res = call {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
7376 %sum = extractvalue {i32, i1} %res, 0
7377 %obit = extractvalue {i32, i1} %res, 1
7378 br i1 %obit, label %carry, label %normal
7379</pre>
7380
7381</div>
7382
7383<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7384<h4>
7385 <a name="int_ssub_overflow">
7386 '<tt>llvm.ssub.with.overflow.*</tt>' Intrinsics
7387 </a>
7388</h4>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7389
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7390<div>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7391
7392<h5>Syntax:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7393<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]7394 on any integer bit width.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7395
7396<pre>
7397 declare {i16, i1} @llvm.ssub.with.overflow.i16(i16 %a, i16 %b)
7398 declare {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
7399 declare {i64, i1} @llvm.ssub.with.overflow.i64(i64 %a, i64 %b)
7400</pre>
7401
7402<h5>Overview:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7403<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7404 a signed subtraction of the two arguments, and indicate whether an overflow
7405 occurred during the signed subtraction.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7406
7407<h5>Arguments:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7408<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]7409 be of integer types of any bit width, but they must have the same bit
7410 width. The second element of the result structure must be of
7411 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
7412 undergo signed subtraction.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7413
7414<h5>Semantics:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7415<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7416 a signed subtraction of the two arguments. They return a structure &mdash;
7417 the first element of which is the subtraction, and the second element of
7418 which is a bit specifying if the signed subtraction resulted in an
7419 overflow.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7420
7421<h5>Examples:</h5>
7422<pre>
7423 %res = call {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
7424 %sum = extractvalue {i32, i1} %res, 0
7425 %obit = extractvalue {i32, i1} %res, 1
7426 br i1 %obit, label %overflow, label %normal
7427</pre>
7428
7429</div>
7430
7431<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7432<h4>
7433 <a name="int_usub_overflow">
7434 '<tt>llvm.usub.with.overflow.*</tt>' Intrinsics
7435 </a>
7436</h4>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7437
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7438<div>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7439
7440<h5>Syntax:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7441<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]7442 on any integer bit width.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7443
7444<pre>
7445 declare {i16, i1} @llvm.usub.with.overflow.i16(i16 %a, i16 %b)
7446 declare {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
7447 declare {i64, i1} @llvm.usub.with.overflow.i64(i64 %a, i64 %b)
7448</pre>
7449
7450<h5>Overview:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7451<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7452 an unsigned subtraction of the two arguments, and indicate whether an
7453 overflow occurred during the unsigned subtraction.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7454
7455<h5>Arguments:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7456<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]7457 be of integer types of any bit width, but they must have the same bit
7458 width. The second element of the result structure must be of
7459 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
7460 undergo unsigned subtraction.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7461
7462<h5>Semantics:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7463<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7464 an unsigned subtraction of the two arguments. They return a structure &mdash;
7465 the first element of which is the subtraction, and the second element of
7466 which is a bit specifying if the unsigned subtraction resulted in an
7467 overflow.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7468
7469<h5>Examples:</h5>
7470<pre>
7471 %res = call {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
7472 %sum = extractvalue {i32, i1} %res, 0
7473 %obit = extractvalue {i32, i1} %res, 1
7474 br i1 %obit, label %overflow, label %normal
7475</pre>
7476
7477</div>
7478
7479<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7480<h4>
7481 <a name="int_smul_overflow">
7482 '<tt>llvm.smul.with.overflow.*</tt>' Intrinsics
7483 </a>
7484</h4>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7485
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7486<div>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7487
7488<h5>Syntax:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7489<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]7490 on any integer bit width.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7491
7492<pre>
7493 declare {i16, i1} @llvm.smul.with.overflow.i16(i16 %a, i16 %b)
7494 declare {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
7495 declare {i64, i1} @llvm.smul.with.overflow.i64(i64 %a, i64 %b)
7496</pre>
7497
7498<h5>Overview:</h5>
7499
7500<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7501 a signed multiplication of the two arguments, and indicate whether an
7502 overflow occurred during the signed multiplication.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7503
7504<h5>Arguments:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7505<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]7506 be of integer types of any bit width, but they must have the same bit
7507 width. The second element of the result structure must be of
7508 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
7509 undergo signed multiplication.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7510
7511<h5>Semantics:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7512<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7513 a signed multiplication of the two arguments. They return a structure &mdash;
7514 the first element of which is the multiplication, and the second element of
7515 which is a bit specifying if the signed multiplication resulted in an
7516 overflow.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7517
7518<h5>Examples:</h5>
7519<pre>
7520 %res = call {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
7521 %sum = extractvalue {i32, i1} %res, 0
7522 %obit = extractvalue {i32, i1} %res, 1
7523 br i1 %obit, label %overflow, label %normal
7524</pre>
7525
Reid Spencer5bf54c82007-04-11 23:23:49 +0000[diff] [blame]7526</div>
7527
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]7528<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7529<h4>
7530 <a name="int_umul_overflow">
7531 '<tt>llvm.umul.with.overflow.*</tt>' Intrinsics
7532 </a>
7533</h4>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]7534
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7535<div>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]7536
7537<h5>Syntax:</h5>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]7538<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]7539 on any integer bit width.</p>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]7540
7541<pre>
7542 declare {i16, i1} @llvm.umul.with.overflow.i16(i16 %a, i16 %b)
7543 declare {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
7544 declare {i64, i1} @llvm.umul.with.overflow.i64(i64 %a, i64 %b)
7545</pre>
7546
7547<h5>Overview:</h5>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]7548<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7549 a unsigned multiplication of the two arguments, and indicate whether an
7550 overflow occurred during the unsigned multiplication.</p>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]7551
7552<h5>Arguments:</h5>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]7553<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]7554 be of integer types of any bit width, but they must have the same bit
7555 width. The second element of the result structure must be of
7556 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
7557 undergo unsigned multiplication.</p>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]7558
7559<h5>Semantics:</h5>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]7560<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7561 an unsigned multiplication of the two arguments. They return a structure
7562 &mdash; the first element of which is the multiplication, and the second
7563 element of which is a bit specifying if the unsigned multiplication resulted
7564 in an overflow.</p>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]7565
7566<h5>Examples:</h5>
7567<pre>
7568 %res = call {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
7569 %sum = extractvalue {i32, i1} %res, 0
7570 %obit = extractvalue {i32, i1} %res, 1
7571 br i1 %obit, label %overflow, label %normal
7572</pre>
7573
7574</div>
7575
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7576</div>
7577
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]7578<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7579<h3>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]7580 <a name="int_fp16">Half Precision Floating Point Intrinsics</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7581</h3>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]7582
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7583<div>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]7584
Chris Lattner022a9fb2010-03-15 04:12:21 +0000[diff] [blame]7585<p>Half precision floating point is a storage-only format. This means that it is
7586 a dense encoding (in memory) but does not support computation in the
7587 format.</p>
Chris Lattnerbbd8bd32010-03-14 23:03:31 +0000[diff] [blame]7588
Chris Lattner022a9fb2010-03-15 04:12:21 +0000[diff] [blame]7589<p>This means that code must first load the half-precision floating point
Chris Lattnerbbd8bd32010-03-14 23:03:31 +0000[diff] [blame]7590 value as an i16, then convert it to float with <a
7591 href="#int_convert_from_fp16"><tt>llvm.convert.from.fp16</tt></a>.
7592 Computation can then be performed on the float value (including extending to
Chris Lattner022a9fb2010-03-15 04:12:21 +0000[diff] [blame]7593 double etc). To store the value back to memory, it is first converted to
7594 float if needed, then converted to i16 with
Chris Lattnerbbd8bd32010-03-14 23:03:31 +0000[diff] [blame]7595 <a href="#int_convert_to_fp16"><tt>llvm.convert.to.fp16</tt></a>, then
7596 storing as an i16 value.</p>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]7597
7598<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7599<h4>
7600 <a name="int_convert_to_fp16">
7601 '<tt>llvm.convert.to.fp16</tt>' Intrinsic
7602 </a>
7603</h4>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]7604
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7605<div>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]7606
7607<h5>Syntax:</h5>
7608<pre>
7609 declare i16 @llvm.convert.to.fp16(f32 %a)
7610</pre>
7611
7612<h5>Overview:</h5>
7613<p>The '<tt>llvm.convert.to.fp16</tt>' intrinsic function performs
7614 a conversion from single precision floating point format to half precision
7615 floating point format.</p>
7616
7617<h5>Arguments:</h5>
7618<p>The intrinsic function contains single argument - the value to be
7619 converted.</p>
7620
7621<h5>Semantics:</h5>
7622<p>The '<tt>llvm.convert.to.fp16</tt>' intrinsic function performs
7623 a conversion from single precision floating point format to half precision
Chris Lattner022a9fb2010-03-15 04:12:21 +0000[diff] [blame]7624 floating point format. The return value is an <tt>i16</tt> which
Chris Lattnerbbd8bd32010-03-14 23:03:31 +0000[diff] [blame]7625 contains the converted number.</p>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]7626
7627<h5>Examples:</h5>
7628<pre>
7629 %res = call i16 @llvm.convert.to.fp16(f32 %a)
7630 store i16 %res, i16* @x, align 2
7631</pre>
7632
7633</div>
7634
7635<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7636<h4>
7637 <a name="int_convert_from_fp16">
7638 '<tt>llvm.convert.from.fp16</tt>' Intrinsic
7639 </a>
7640</h4>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]7641
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7642<div>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]7643
7644<h5>Syntax:</h5>
7645<pre>
7646 declare f32 @llvm.convert.from.fp16(i16 %a)
7647</pre>
7648
7649<h5>Overview:</h5>
7650<p>The '<tt>llvm.convert.from.fp16</tt>' intrinsic function performs
7651 a conversion from half precision floating point format to single precision
7652 floating point format.</p>
7653
7654<h5>Arguments:</h5>
7655<p>The intrinsic function contains single argument - the value to be
7656 converted.</p>
7657
7658<h5>Semantics:</h5>
7659<p>The '<tt>llvm.convert.from.fp16</tt>' intrinsic function performs a
Chris Lattner022a9fb2010-03-15 04:12:21 +0000[diff] [blame]7660 conversion from half single precision floating point format to single
Chris Lattnerbbd8bd32010-03-14 23:03:31 +0000[diff] [blame]7661 precision floating point format. The input half-float value is represented by
7662 an <tt>i16</tt> value.</p>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]7663
7664<h5>Examples:</h5>
7665<pre>
7666 %a = load i16* @x, align 2
7667 %res = call f32 @llvm.convert.from.fp16(i16 %a)
7668</pre>
7669
7670</div>
7671
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7672</div>
7673
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]7674<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7675<h3>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]7676 <a name="int_debugger">Debugger Intrinsics</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7677</h3>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]7678
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7679<div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]7680
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7681<p>The LLVM debugger intrinsics (which all start with <tt>llvm.dbg.</tt>
7682 prefix), are described in
7683 the <a href="SourceLevelDebugging.html#format_common_intrinsics">LLVM Source
7684 Level Debugging</a> document.</p>
7685
7686</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]7687
Jim Laskey2211f492007-03-14 19:31:19 +0000[diff] [blame]7688<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7689<h3>
Jim Laskey2211f492007-03-14 19:31:19 +0000[diff] [blame]7690 <a name="int_eh">Exception Handling Intrinsics</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7691</h3>
Jim Laskey2211f492007-03-14 19:31:19 +0000[diff] [blame]7692
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7693<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7694
7695<p>The LLVM exception handling intrinsics (which all start with
7696 <tt>llvm.eh.</tt> prefix), are described in
7697 the <a href="ExceptionHandling.html#format_common_intrinsics">LLVM Exception
7698 Handling</a> document.</p>
7699
Jim Laskey2211f492007-03-14 19:31:19 +0000[diff] [blame]7700</div>
7701
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]7702<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7703<h3>
Duncan Sandsa0984362011-09-06 13:37:06 +0000[diff] [blame]7704 <a name="int_trampoline">Trampoline Intrinsics</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7705</h3>
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]7706
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7707<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7708
Duncan Sandsa0984362011-09-06 13:37:06 +0000[diff] [blame]7709<p>These intrinsics make it possible to excise one parameter, marked with
Dan Gohman3770af52010-07-02 23:18:08 +0000[diff] [blame]7710 the <a href="#nest"><tt>nest</tt></a> attribute, from a function.
7711 The result is a callable
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7712 function pointer lacking the nest parameter - the caller does not need to
7713 provide a value for it. Instead, the value to use is stored in advance in a
7714 "trampoline", a block of memory usually allocated on the stack, which also
7715 contains code to splice the nest value into the argument list. This is used
7716 to implement the GCC nested function address extension.</p>
7717
7718<p>For example, if the function is
7719 <tt>i32 f(i8* nest %c, i32 %x, i32 %y)</tt> then the resulting function
7720 pointer has signature <tt>i32 (i32, i32)*</tt>. It can be created as
7721 follows:</p>
7722
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]7723<pre class="doc_code">
Duncan Sands86e01192007-09-11 14:10:23 +0000[diff] [blame]7724 %tramp = alloca [10 x i8], align 4 ; size and alignment only correct for X86
7725 %tramp1 = getelementptr [10 x i8]* %tramp, i32 0, i32 0
Duncan Sandsa0984362011-09-06 13:37:06 +0000[diff] [blame]7726 call i8* @llvm.init.trampoline(i8* %tramp1, i8* bitcast (i32 (i8*, i32, i32)* @f to i8*), i8* %nval)
7727 %p = call i8* @llvm.adjust.trampoline(i8* %tramp1)
Duncan Sands86e01192007-09-11 14:10:23 +0000[diff] [blame]7728 %fp = bitcast i8* %p to i32 (i32, i32)*
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]7729</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7730
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7731<p>The call <tt>%val = call i32 %fp(i32 %x, i32 %y)</tt> is then equivalent
7732 to <tt>%val = call i32 %f(i8* %nval, i32 %x, i32 %y)</tt>.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7733
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]7734<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7735<h4>
7736 <a name="int_it">
7737 '<tt>llvm.init.trampoline</tt>' Intrinsic
7738 </a>
7739</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7740
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7741<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7742
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]7743<h5>Syntax:</h5>
7744<pre>
Duncan Sandsa0984362011-09-06 13:37:06 +0000[diff] [blame]7745 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]7746</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7747
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]7748<h5>Overview:</h5>
Duncan Sandsa0984362011-09-06 13:37:06 +0000[diff] [blame]7749<p>This fills the memory pointed to by <tt>tramp</tt> with executable code,
7750 turning it into a trampoline.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7751
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]7752<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7753<p>The <tt>llvm.init.trampoline</tt> intrinsic takes three arguments, all
7754 pointers. The <tt>tramp</tt> argument must point to a sufficiently large and
7755 sufficiently aligned block of memory; this memory is written to by the
7756 intrinsic. Note that the size and the alignment are target-specific - LLVM
7757 currently provides no portable way of determining them, so a front-end that
7758 generates this intrinsic needs to have some target-specific knowledge.
7759 The <tt>func</tt> argument must hold a function bitcast to
7760 an <tt>i8*</tt>.</p>
7761
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]7762<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7763<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]7764 dependent code, turning it into a function. Then <tt>tramp</tt> needs to be
7765 passed to <a href="#int_at">llvm.adjust.trampoline</a> to get a pointer
7766 which can be <a href="#int_trampoline">bitcast (to a new function) and
7767 called</a>. The new function's signature is the same as that of
7768 <tt>func</tt> with any arguments marked with the <tt>nest</tt> attribute
7769 removed. At most one such <tt>nest</tt> argument is allowed, and it must be of
7770 pointer type. Calling the new function is equivalent to calling <tt>func</tt>
7771 with the same argument list, but with <tt>nval</tt> used for the missing
7772 <tt>nest</tt> argument. If, after calling <tt>llvm.init.trampoline</tt>, the
7773 memory pointed to by <tt>tramp</tt> is modified, then the effect of any later call
7774 to the returned function pointer is undefined.</p>
7775</div>
7776
7777<!-- _______________________________________________________________________ -->
7778<h4>
7779 <a name="int_at">
7780 '<tt>llvm.adjust.trampoline</tt>' Intrinsic
7781 </a>
7782</h4>
7783
7784<div>
7785
7786<h5>Syntax:</h5>
7787<pre>
7788 declare i8* @llvm.adjust.trampoline(i8* &lt;tramp&gt;)
7789</pre>
7790
7791<h5>Overview:</h5>
7792<p>This performs any required machine-specific adjustment to the address of a
7793 trampoline (passed as <tt>tramp</tt>).</p>
7794
7795<h5>Arguments:</h5>
7796<p><tt>tramp</tt> must point to a block of memory which already has trampoline code
7797 filled in by a previous call to <a href="#int_it"><tt>llvm.init.trampoline</tt>
7798 </a>.</p>
7799
7800<h5>Semantics:</h5>
7801<p>On some architectures the address of the code to be executed needs to be
7802 different to the address where the trampoline is actually stored. This
7803 intrinsic returns the executable address corresponding to <tt>tramp</tt>
7804 after performing the required machine specific adjustments.
7805 The pointer returned can then be <a href="#int_trampoline"> bitcast and
7806 executed</a>.
7807</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7808
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]7809</div>
7810
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7811</div>
7812
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]7813<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7814<h3>
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7815 <a name="int_atomics">Atomic Operations and Synchronization Intrinsics</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7816</h3>
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7817
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7818<div>
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7819
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7820<p>These intrinsic functions expand the "universal IR" of LLVM to represent
7821 hardware constructs for atomic operations and memory synchronization. This
7822 provides an interface to the hardware, not an interface to the programmer. It
7823 is aimed at a low enough level to allow any programming models or APIs
7824 (Application Programming Interfaces) which need atomic behaviors to map
7825 cleanly onto it. It is also modeled primarily on hardware behavior. Just as
7826 hardware provides a "universal IR" for source languages, it also provides a
7827 starting point for developing a "universal" atomic operation and
7828 synchronization IR.</p>
7829
7830<p>These do <em>not</em> form an API such as high-level threading libraries,
7831 software transaction memory systems, atomic primitives, and intrinsic
7832 functions as found in BSD, GNU libc, atomic_ops, APR, and other system and
7833 application libraries. The hardware interface provided by LLVM should allow
7834 a clean implementation of all of these APIs and parallel programming models.
7835 No one model or paradigm should be selected above others unless the hardware
7836 itself ubiquitously does so.</p>
7837
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7838<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7839<h4>
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7840 <a name="int_memory_barrier">'<tt>llvm.memory.barrier</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7841</h4>
7842
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7843<div>
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7844<h5>Syntax:</h5>
7845<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7846 declare void @llvm.memory.barrier(i1 &lt;ll&gt;, i1 &lt;ls&gt;, i1 &lt;sl&gt;, i1 &lt;ss&gt;, i1 &lt;device&gt;)
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7847</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7848
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7849<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7850<p>The <tt>llvm.memory.barrier</tt> intrinsic guarantees ordering between
7851 specific pairs of memory access types.</p>
7852
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7853<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7854<p>The <tt>llvm.memory.barrier</tt> intrinsic requires five boolean arguments.
7855 The first four arguments enables a specific barrier as listed below. The
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]7856 fifth argument specifies that the barrier applies to io or device or uncached
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7857 memory.</p>
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7858
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7859<ul>
7860 <li><tt>ll</tt>: load-load barrier</li>
7861 <li><tt>ls</tt>: load-store barrier</li>
7862 <li><tt>sl</tt>: store-load barrier</li>
7863 <li><tt>ss</tt>: store-store barrier</li>
7864 <li><tt>device</tt>: barrier applies to device and uncached memory also.</li>
7865</ul>
7866
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7867<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7868<p>This intrinsic causes the system to enforce some ordering constraints upon
7869 the loads and stores of the program. This barrier does not
7870 indicate <em>when</em> any events will occur, it only enforces
7871 an <em>order</em> in which they occur. For any of the specified pairs of load
7872 and store operations (f.ex. load-load, or store-load), all of the first
7873 operations preceding the barrier will complete before any of the second
7874 operations succeeding the barrier begin. Specifically the semantics for each
7875 pairing is as follows:</p>
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7876
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7877<ul>
7878 <li><tt>ll</tt>: All loads before the barrier must complete before any load
7879 after the barrier begins.</li>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]7880 <li><tt>ls</tt>: All loads before the barrier must complete before any
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7881 store after the barrier begins.</li>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]7882 <li><tt>ss</tt>: All stores before the barrier must complete before any
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7883 store after the barrier begins.</li>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]7884 <li><tt>sl</tt>: All stores before the barrier must complete before any
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7885 load after the barrier begins.</li>
7886</ul>
7887
7888<p>These semantics are applied with a logical "and" behavior when more than one
7889 is enabled in a single memory barrier intrinsic.</p>
7890
7891<p>Backends may implement stronger barriers than those requested when they do
7892 not support as fine grained a barrier as requested. Some architectures do
7893 not need all types of barriers and on such architectures, these become
7894 noops.</p>
7895
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7896<h5>Example:</h5>
7897<pre>
Victor Hernandeza70c6df2009-10-26 23:44:29 +0000[diff] [blame]7898%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7899%ptr = bitcast i8* %mallocP to i32*
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7900 store i32 4, %ptr
7901
7902%result1 = load i32* %ptr <i>; yields {i32}:result1 = 4</i>
Evan Cheng0ac49c62011-06-29 17:14:00 +0000[diff] [blame]7903 call void @llvm.memory.barrier(i1 false, i1 true, i1 false, i1 false, i1 true)
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7904 <i>; guarantee the above finishes</i>
7905 store i32 8, %ptr <i>; before this begins</i>
7906</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7907
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7908</div>
7909
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7910<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7911<h4>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7912 <a name="int_atomic_cmp_swap">'<tt>llvm.atomic.cmp.swap.*</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7913</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7914
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7915<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7916
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7917<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7918<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.cmp.swap</tt> on
7919 any integer bit width and for different address spaces. Not all targets
7920 support all bit widths however.</p>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7921
7922<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7923 declare i8 @llvm.atomic.cmp.swap.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;cmp&gt;, i8 &lt;val&gt;)
7924 declare i16 @llvm.atomic.cmp.swap.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;cmp&gt;, i16 &lt;val&gt;)
7925 declare i32 @llvm.atomic.cmp.swap.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;cmp&gt;, i32 &lt;val&gt;)
7926 declare i64 @llvm.atomic.cmp.swap.i64.p0i64(i64* &lt;ptr&gt;, i64 &lt;cmp&gt;, i64 &lt;val&gt;)
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7927</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7928
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7929<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7930<p>This loads a value in memory and compares it to a given value. If they are
7931 equal, it stores a new value into the memory.</p>
7932
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7933<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7934<p>The <tt>llvm.atomic.cmp.swap</tt> intrinsic takes three arguments. The result
7935 as well as both <tt>cmp</tt> and <tt>val</tt> must be integer values with the
7936 same bit width. The <tt>ptr</tt> argument must be a pointer to a value of
7937 this integer type. While any bit width integer may be used, targets may only
7938 lower representations they support in hardware.</p>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7939
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7940<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7941<p>This entire intrinsic must be executed atomically. It first loads the value
7942 in memory pointed to by <tt>ptr</tt> and compares it with the
7943 value <tt>cmp</tt>. If they are equal, <tt>val</tt> is stored into the
7944 memory. The loaded value is yielded in all cases. This provides the
7945 equivalent of an atomic compare-and-swap operation within the SSA
7946 framework.</p>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7947
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7948<h5>Examples:</h5>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7949<pre>
Victor Hernandeza70c6df2009-10-26 23:44:29 +0000[diff] [blame]7950%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7951%ptr = bitcast i8* %mallocP to i32*
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7952 store i32 4, %ptr
7953
7954%val1 = add i32 4, 4
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7955%result1 = call i32 @llvm.atomic.cmp.swap.i32.p0i32(i32* %ptr, i32 4, %val1)
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7956 <i>; yields {i32}:result1 = 4</i>
7957%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
7958%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
7959
7960%val2 = add i32 1, 1
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7961%result2 = call i32 @llvm.atomic.cmp.swap.i32.p0i32(i32* %ptr, i32 5, %val2)
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7962 <i>; yields {i32}:result2 = 8</i>
7963%stored2 = icmp eq i32 %result2, 5 <i>; yields {i1}:stored2 = false</i>
7964
7965%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 8</i>
7966</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7967
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7968</div>
7969
7970<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7971<h4>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7972 <a name="int_atomic_swap">'<tt>llvm.atomic.swap.*</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7973</h4>
7974
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7975<div>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7976<h5>Syntax:</h5>
7977
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7978<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.swap</tt> on any
7979 integer bit width. Not all targets support all bit widths however.</p>
7980
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7981<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7982 declare i8 @llvm.atomic.swap.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;val&gt;)
7983 declare i16 @llvm.atomic.swap.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;val&gt;)
7984 declare i32 @llvm.atomic.swap.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;val&gt;)
7985 declare i64 @llvm.atomic.swap.i64.p0i64(i64* &lt;ptr&gt;, i64 &lt;val&gt;)
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7986</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7987
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7988<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7989<p>This intrinsic loads the value stored in memory at <tt>ptr</tt> and yields
7990 the value from memory. It then stores the value in <tt>val</tt> in the memory
7991 at <tt>ptr</tt>.</p>
7992
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7993<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7994<p>The <tt>llvm.atomic.swap</tt> intrinsic takes two arguments. Both
7995 the <tt>val</tt> argument and the result must be integers of the same bit
7996 width. The first argument, <tt>ptr</tt>, must be a pointer to a value of this
7997 integer type. The targets may only lower integer representations they
7998 support.</p>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7999
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]8000<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8001<p>This intrinsic loads the value pointed to by <tt>ptr</tt>, yields it, and
8002 stores <tt>val</tt> back into <tt>ptr</tt> atomically. This provides the
8003 equivalent of an atomic swap operation within the SSA framework.</p>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]8004
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]8005<h5>Examples:</h5>
8006<pre>
Victor Hernandeza70c6df2009-10-26 23:44:29 +0000[diff] [blame]8007%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
8008%ptr = bitcast i8* %mallocP to i32*
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]8009 store i32 4, %ptr
8010
8011%val1 = add i32 4, 4
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]8012%result1 = call i32 @llvm.atomic.swap.i32.p0i32(i32* %ptr, i32 %val1)
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]8013 <i>; yields {i32}:result1 = 4</i>
8014%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
8015%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
8016
8017%val2 = add i32 1, 1
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]8018%result2 = call i32 @llvm.atomic.swap.i32.p0i32(i32* %ptr, i32 %val2)
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]8019 <i>; yields {i32}:result2 = 8</i>
8020
8021%stored2 = icmp eq i32 %result2, 8 <i>; yields {i1}:stored2 = true</i>
8022%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 2</i>
8023</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8024
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]8025</div>
8026
8027<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8028<h4>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]8029 <a name="int_atomic_load_add">'<tt>llvm.atomic.load.add.*</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8030</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8031
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]8032<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8033
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]8034<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8035<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.load.add</tt> on
8036 any integer bit width. Not all targets support all bit widths however.</p>
8037
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]8038<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]8039 declare i8 @llvm.atomic.load.add.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
8040 declare i16 @llvm.atomic.load.add.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
8041 declare i32 @llvm.atomic.load.add.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
8042 declare i64 @llvm.atomic.load.add.i64.p0i64(i64* &lt;ptr&gt;, i64 &lt;delta&gt;)
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]8043</pre>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]8044
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8045<h5>Overview:</h5>
8046<p>This intrinsic adds <tt>delta</tt> to the value stored in memory
8047 at <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.</p>
8048
8049<h5>Arguments:</h5>
8050<p>The intrinsic takes two arguments, the first a pointer to an integer value
8051 and the second an integer value. The result is also an integer value. These
8052 integer types can have any bit width, but they must all have the same bit
8053 width. The targets may only lower integer representations they support.</p>
8054
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]8055<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8056<p>This intrinsic does a series of operations atomically. It first loads the
8057 value stored at <tt>ptr</tt>. It then adds <tt>delta</tt>, stores the result
8058 to <tt>ptr</tt>. It yields the original value stored at <tt>ptr</tt>.</p>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]8059
8060<h5>Examples:</h5>
8061<pre>
Victor Hernandeza70c6df2009-10-26 23:44:29 +0000[diff] [blame]8062%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
8063%ptr = bitcast i8* %mallocP to i32*
8064 store i32 4, %ptr
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]8065%result1 = call i32 @llvm.atomic.load.add.i32.p0i32(i32* %ptr, i32 4)
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]8066 <i>; yields {i32}:result1 = 4</i>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]8067%result2 = call i32 @llvm.atomic.load.add.i32.p0i32(i32* %ptr, i32 2)
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]8068 <i>; yields {i32}:result2 = 8</i>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]8069%result3 = call i32 @llvm.atomic.load.add.i32.p0i32(i32* %ptr, i32 5)
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]8070 <i>; yields {i32}:result3 = 10</i>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]8071%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 15</i>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]8072</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8073
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]8074</div>
8075
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]8076<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8077<h4>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]8078 <a name="int_atomic_load_sub">'<tt>llvm.atomic.load.sub.*</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8079</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8080
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]8081<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8082
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]8083<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8084<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.load.sub</tt> on
8085 any integer bit width and for different address spaces. Not all targets
8086 support all bit widths however.</p>
8087
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]8088<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]8089 declare i8 @llvm.atomic.load.sub.i8.p0i32(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
8090 declare i16 @llvm.atomic.load.sub.i16.p0i32(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
8091 declare i32 @llvm.atomic.load.sub.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
8092 declare i64 @llvm.atomic.load.sub.i64.p0i32(i64* &lt;ptr&gt;, i64 &lt;delta&gt;)
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]8093</pre>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]8094
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8095<h5>Overview:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]8096<p>This intrinsic subtracts <tt>delta</tt> to the value stored in memory at
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8097 <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.</p>
8098
8099<h5>Arguments:</h5>
8100<p>The intrinsic takes two arguments, the first a pointer to an integer value
8101 and the second an integer value. The result is also an integer value. These
8102 integer types can have any bit width, but they must all have the same bit
8103 width. The targets may only lower integer representations they support.</p>
8104
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]8105<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8106<p>This intrinsic does a series of operations atomically. It first loads the
8107 value stored at <tt>ptr</tt>. It then subtracts <tt>delta</tt>, stores the
8108 result to <tt>ptr</tt>. It yields the original value stored
8109 at <tt>ptr</tt>.</p>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]8110
8111<h5>Examples:</h5>
8112<pre>
Victor Hernandeza70c6df2009-10-26 23:44:29 +0000[diff] [blame]8113%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
8114%ptr = bitcast i8* %mallocP to i32*
8115 store i32 8, %ptr
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]8116%result1 = call i32 @llvm.atomic.load.sub.i32.p0i32(i32* %ptr, i32 4)
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]8117 <i>; yields {i32}:result1 = 8</i>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]8118%result2 = call i32 @llvm.atomic.load.sub.i32.p0i32(i32* %ptr, i32 2)
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]8119 <i>; yields {i32}:result2 = 4</i>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]8120%result3 = call i32 @llvm.atomic.load.sub.i32.p0i32(i32* %ptr, i32 5)
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]8121 <i>; yields {i32}:result3 = 2</i>
8122%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = -3</i>
8123</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8124
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]8125</div>
8126
8127<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8128<h4>
8129 <a name="int_atomic_load_and">
8130 '<tt>llvm.atomic.load.and.*</tt>' Intrinsic
8131 </a>
8132 <br>
8133 <a name="int_atomic_load_nand">
8134 '<tt>llvm.atomic.load.nand.*</tt>' Intrinsic
8135 </a>
8136 <br>
8137 <a name="int_atomic_load_or">
8138 '<tt>llvm.atomic.load.or.*</tt>' Intrinsic
8139 </a>
8140 <br>
8141 <a name="int_atomic_load_xor">
8142 '<tt>llvm.atomic.load.xor.*</tt>' Intrinsic
8143 </a>
8144</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8145
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]8146<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8147
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]8148<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8149<p>These are overloaded intrinsics. You can
8150 use <tt>llvm.atomic.load_and</tt>, <tt>llvm.atomic.load_nand</tt>,
8151 <tt>llvm.atomic.load_or</tt>, and <tt>llvm.atomic.load_xor</tt> on any integer
8152 bit width and for different address spaces. Not all targets support all bit
8153 widths however.</p>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]8154
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8155<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]8156 declare i8 @llvm.atomic.load.and.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
8157 declare i16 @llvm.atomic.load.and.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
8158 declare i32 @llvm.atomic.load.and.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
8159 declare i64 @llvm.atomic.load.and.i64.p0i64(i64* &lt;ptr&gt;, i64 &lt;delta&gt;)
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]8160</pre>
8161
8162<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]8163 declare i8 @llvm.atomic.load.or.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
8164 declare i16 @llvm.atomic.load.or.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
8165 declare i32 @llvm.atomic.load.or.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
8166 declare i64 @llvm.atomic.load.or.i64.p0i64(i64* &lt;ptr&gt;, i64 &lt;delta&gt;)
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]8167</pre>
8168
8169<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]8170 declare i8 @llvm.atomic.load.nand.i8.p0i32(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
8171 declare i16 @llvm.atomic.load.nand.i16.p0i32(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
8172 declare i32 @llvm.atomic.load.nand.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
8173 declare i64 @llvm.atomic.load.nand.i64.p0i32(i64* &lt;ptr&gt;, i64 &lt;delta&gt;)
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]8174</pre>
8175
8176<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]8177 declare i8 @llvm.atomic.load.xor.i8.p0i32(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
8178 declare i16 @llvm.atomic.load.xor.i16.p0i32(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
8179 declare i32 @llvm.atomic.load.xor.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
8180 declare i64 @llvm.atomic.load.xor.i64.p0i32(i64* &lt;ptr&gt;, i64 &lt;delta&gt;)
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]8181</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8182
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]8183<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8184<p>These intrinsics bitwise the operation (and, nand, or, xor) <tt>delta</tt> to
8185 the value stored in memory at <tt>ptr</tt>. It yields the original value
8186 at <tt>ptr</tt>.</p>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]8187
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8188<h5>Arguments:</h5>
8189<p>These intrinsics take two arguments, the first a pointer to an integer value
8190 and the second an integer value. The result is also an integer value. These
8191 integer types can have any bit width, but they must all have the same bit
8192 width. The targets may only lower integer representations they support.</p>
8193
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]8194<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8195<p>These intrinsics does a series of operations atomically. They first load the
8196 value stored at <tt>ptr</tt>. They then do the bitwise
8197 operation <tt>delta</tt>, store the result to <tt>ptr</tt>. They yield the
8198 original value stored at <tt>ptr</tt>.</p>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]8199
8200<h5>Examples:</h5>
8201<pre>
Victor Hernandeza70c6df2009-10-26 23:44:29 +0000[diff] [blame]8202%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
8203%ptr = bitcast i8* %mallocP to i32*
8204 store i32 0x0F0F, %ptr
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]8205%result0 = call i32 @llvm.atomic.load.nand.i32.p0i32(i32* %ptr, i32 0xFF)
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]8206 <i>; yields {i32}:result0 = 0x0F0F</i>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]8207%result1 = call i32 @llvm.atomic.load.and.i32.p0i32(i32* %ptr, i32 0xFF)
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]8208 <i>; yields {i32}:result1 = 0xFFFFFFF0</i>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]8209%result2 = call i32 @llvm.atomic.load.or.i32.p0i32(i32* %ptr, i32 0F)
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]8210 <i>; yields {i32}:result2 = 0xF0</i>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]8211%result3 = call i32 @llvm.atomic.load.xor.i32.p0i32(i32* %ptr, i32 0F)
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]8212 <i>; yields {i32}:result3 = FF</i>
8213%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = F0</i>
8214</pre>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]8215
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8216</div>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]8217
8218<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8219<h4>
8220 <a name="int_atomic_load_max">
8221 '<tt>llvm.atomic.load.max.*</tt>' Intrinsic
8222 </a>
8223 <br>
8224 <a name="int_atomic_load_min">
8225 '<tt>llvm.atomic.load.min.*</tt>' Intrinsic
8226 </a>
8227 <br>
8228 <a name="int_atomic_load_umax">
8229 '<tt>llvm.atomic.load.umax.*</tt>' Intrinsic
8230 </a>
8231 <br>
8232 <a name="int_atomic_load_umin">
8233 '<tt>llvm.atomic.load.umin.*</tt>' Intrinsic
8234 </a>
8235</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8236
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]8237<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8238
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]8239<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8240<p>These are overloaded intrinsics. You can use <tt>llvm.atomic.load_max</tt>,
8241 <tt>llvm.atomic.load_min</tt>, <tt>llvm.atomic.load_umax</tt>, and
8242 <tt>llvm.atomic.load_umin</tt> on any integer bit width and for different
8243 address spaces. Not all targets support all bit widths however.</p>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]8244
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8245<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]8246 declare i8 @llvm.atomic.load.max.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
8247 declare i16 @llvm.atomic.load.max.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
8248 declare i32 @llvm.atomic.load.max.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
8249 declare i64 @llvm.atomic.load.max.i64.p0i64(i64* &lt;ptr&gt;, i64 &lt;delta&gt;)
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]8250</pre>
8251
8252<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]8253 declare i8 @llvm.atomic.load.min.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
8254 declare i16 @llvm.atomic.load.min.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
8255 declare i32 @llvm.atomic.load.min.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
8256 declare i64 @llvm.atomic.load.min.i64.p0i64(i64* &lt;ptr&gt;, i64 &lt;delta&gt;)
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]8257</pre>
8258
8259<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]8260 declare i8 @llvm.atomic.load.umax.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
8261 declare i16 @llvm.atomic.load.umax.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
8262 declare i32 @llvm.atomic.load.umax.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
8263 declare i64 @llvm.atomic.load.umax.i64.p0i64(i64* &lt;ptr&gt;, i64 &lt;delta&gt;)
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]8264</pre>
8265
8266<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]8267 declare i8 @llvm.atomic.load.umin.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
8268 declare i16 @llvm.atomic.load.umin.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
8269 declare i32 @llvm.atomic.load.umin.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
8270 declare i64 @llvm.atomic.load.umin.i64.p0i64(i64* &lt;ptr&gt;, i64 &lt;delta&gt;)
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]8271</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8272
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]8273<h5>Overview:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]8274<p>These intrinsics takes the signed or unsigned minimum or maximum of
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8275 <tt>delta</tt> and the value stored in memory at <tt>ptr</tt>. It yields the
8276 original value at <tt>ptr</tt>.</p>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]8277
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8278<h5>Arguments:</h5>
8279<p>These intrinsics take two arguments, the first a pointer to an integer value
8280 and the second an integer value. The result is also an integer value. These
8281 integer types can have any bit width, but they must all have the same bit
8282 width. The targets may only lower integer representations they support.</p>
8283
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]8284<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8285<p>These intrinsics does a series of operations atomically. They first load the
8286 value stored at <tt>ptr</tt>. They then do the signed or unsigned min or
8287 max <tt>delta</tt> and the value, store the result to <tt>ptr</tt>. They
8288 yield the original value stored at <tt>ptr</tt>.</p>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]8289
8290<h5>Examples:</h5>
8291<pre>
Victor Hernandeza70c6df2009-10-26 23:44:29 +0000[diff] [blame]8292%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
8293%ptr = bitcast i8* %mallocP to i32*
8294 store i32 7, %ptr
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]8295%result0 = call i32 @llvm.atomic.load.min.i32.p0i32(i32* %ptr, i32 -2)
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]8296 <i>; yields {i32}:result0 = 7</i>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]8297%result1 = call i32 @llvm.atomic.load.max.i32.p0i32(i32* %ptr, i32 8)
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]8298 <i>; yields {i32}:result1 = -2</i>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]8299%result2 = call i32 @llvm.atomic.load.umin.i32.p0i32(i32* %ptr, i32 10)
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]8300 <i>; yields {i32}:result2 = 8</i>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]8301%result3 = call i32 @llvm.atomic.load.umax.i32.p0i32(i32* %ptr, i32 30)
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]8302 <i>; yields {i32}:result3 = 8</i>
8303%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 30</i>
8304</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8305
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]8306</div>
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]8307
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]8308</div>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]8309
8310<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8311<h3>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]8312 <a name="int_memorymarkers">Memory Use Markers</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8313</h3>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]8314
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]8315<div>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]8316
8317<p>This class of intrinsics exists to information about the lifetime of memory
8318 objects and ranges where variables are immutable.</p>
8319
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]8320<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8321<h4>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]8322 <a name="int_lifetime_start">'<tt>llvm.lifetime.start</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8323</h4>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]8324
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]8325<div>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]8326
8327<h5>Syntax:</h5>
8328<pre>
8329 declare void @llvm.lifetime.start(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
8330</pre>
8331
8332<h5>Overview:</h5>
8333<p>The '<tt>llvm.lifetime.start</tt>' intrinsic specifies the start of a memory
8334 object's lifetime.</p>
8335
8336<h5>Arguments:</h5>
Nick Lewycky9bc89042009-10-13 07:57:33 +0000[diff] [blame]8337<p>The first argument is a constant integer representing the size of the
8338 object, or -1 if it is variable sized. The second argument is a pointer to
8339 the object.</p>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]8340
8341<h5>Semantics:</h5>
8342<p>This intrinsic indicates that before this point in the code, the value of the
8343 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]8344 never be used and has an undefined value. A load from the pointer that
8345 precedes this intrinsic can be replaced with
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]8346 <tt>'<a href="#undefvalues">undef</a>'</tt>.</p>
8347
8348</div>
8349
8350<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8351<h4>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]8352 <a name="int_lifetime_end">'<tt>llvm.lifetime.end</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8353</h4>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]8354
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]8355<div>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]8356
8357<h5>Syntax:</h5>
8358<pre>
8359 declare void @llvm.lifetime.end(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
8360</pre>
8361
8362<h5>Overview:</h5>
8363<p>The '<tt>llvm.lifetime.end</tt>' intrinsic specifies the end of a memory
8364 object's lifetime.</p>
8365
8366<h5>Arguments:</h5>
Nick Lewycky9bc89042009-10-13 07:57:33 +0000[diff] [blame]8367<p>The first argument is a constant integer representing the size of the
8368 object, or -1 if it is variable sized. The second argument is a pointer to
8369 the object.</p>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]8370
8371<h5>Semantics:</h5>
8372<p>This intrinsic indicates that after this point in the code, the value of the
8373 memory pointed to by <tt>ptr</tt> is dead. This means that it is known to
8374 never be used and has an undefined value. Any stores into the memory object
8375 following this intrinsic may be removed as dead.
8376
8377</div>
8378
8379<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8380<h4>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]8381 <a name="int_invariant_start">'<tt>llvm.invariant.start</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8382</h4>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]8383
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]8384<div>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]8385
8386<h5>Syntax:</h5>
8387<pre>
Nick Lewycky2965d3e2010-11-30 04:13:41 +0000[diff] [blame]8388 declare {}* @llvm.invariant.start(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]8389</pre>
8390
8391<h5>Overview:</h5>
8392<p>The '<tt>llvm.invariant.start</tt>' intrinsic specifies that the contents of
8393 a memory object will not change.</p>
8394
8395<h5>Arguments:</h5>
Nick Lewycky9bc89042009-10-13 07:57:33 +0000[diff] [blame]8396<p>The first argument is a constant integer representing the size of the
8397 object, or -1 if it is variable sized. The second argument is a pointer to
8398 the object.</p>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]8399
8400<h5>Semantics:</h5>
8401<p>This intrinsic indicates that until an <tt>llvm.invariant.end</tt> that uses
8402 the return value, the referenced memory location is constant and
8403 unchanging.</p>
8404
8405</div>
8406
8407<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8408<h4>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]8409 <a name="int_invariant_end">'<tt>llvm.invariant.end</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8410</h4>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]8411
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]8412<div>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]8413
8414<h5>Syntax:</h5>
8415<pre>
8416 declare void @llvm.invariant.end({}* &lt;start&gt;, i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
8417</pre>
8418
8419<h5>Overview:</h5>
8420<p>The '<tt>llvm.invariant.end</tt>' intrinsic specifies that the contents of
8421 a memory object are mutable.</p>
8422
8423<h5>Arguments:</h5>
8424<p>The first argument is the matching <tt>llvm.invariant.start</tt> intrinsic.
Nick Lewycky9bc89042009-10-13 07:57:33 +0000[diff] [blame]8425 The second argument is a constant integer representing the size of the
8426 object, or -1 if it is variable sized and the third argument is a pointer
8427 to the object.</p>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]8428
8429<h5>Semantics:</h5>
8430<p>This intrinsic indicates that the memory is mutable again.</p>
8431
8432</div>
8433
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]8434</div>
8435
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]8436<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8437<h3>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]8438 <a name="int_general">General Intrinsics</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8439</h3>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]8440
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]8441<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8442
8443<p>This class of intrinsics is designed to be generic and has no specific
8444 purpose.</p>
8445
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]8446<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8447<h4>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]8448 <a name="int_var_annotation">'<tt>llvm.var.annotation</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8449</h4>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]8450
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]8451<div>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]8452
8453<h5>Syntax:</h5>
8454<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]8455 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]8456</pre>
8457
8458<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8459<p>The '<tt>llvm.var.annotation</tt>' intrinsic.</p>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]8460
8461<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8462<p>The first argument is a pointer to a value, the second is a pointer to a
8463 global string, the third is a pointer to a global string which is the source
8464 file name, and the last argument is the line number.</p>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]8465
8466<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8467<p>This intrinsic allows annotation of local variables with arbitrary strings.
8468 This can be useful for special purpose optimizations that want to look for
John Criswellf0d536a2011-08-19 16:57:55 +0000[diff] [blame]8469 these annotations. These have no other defined use; they are ignored by code
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8470 generation and optimization.</p>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]8471
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]8472</div>
8473
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]8474<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8475<h4>
Tanya Lattner0186a652007-09-21 23:57:59 +0000[diff] [blame]8476 <a name="int_annotation">'<tt>llvm.annotation.*</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8477</h4>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]8478
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]8479<div>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]8480
8481<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8482<p>This is an overloaded intrinsic. You can use '<tt>llvm.annotation</tt>' on
8483 any integer bit width.</p>
8484
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]8485<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]8486 declare i8 @llvm.annotation.i8(i8 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
8487 declare i16 @llvm.annotation.i16(i16 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
8488 declare i32 @llvm.annotation.i32(i32 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
8489 declare i64 @llvm.annotation.i64(i64 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
8490 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]8491</pre>
8492
8493<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8494<p>The '<tt>llvm.annotation</tt>' intrinsic.</p>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]8495
8496<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8497<p>The first argument is an integer value (result of some expression), the
8498 second is a pointer to a global string, the third is a pointer to a global
8499 string which is the source file name, and the last argument is the line
8500 number. It returns the value of the first argument.</p>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]8501
8502<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8503<p>This intrinsic allows annotations to be put on arbitrary expressions with
8504 arbitrary strings. This can be useful for special purpose optimizations that
John Criswellf0d536a2011-08-19 16:57:55 +0000[diff] [blame]8505 want to look for these annotations. These have no other defined use; they
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8506 are ignored by code generation and optimization.</p>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]8507
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]8508</div>
Jim Laskey2211f492007-03-14 19:31:19 +0000[diff] [blame]8509
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]8510<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8511<h4>
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]8512 <a name="int_trap">'<tt>llvm.trap</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8513</h4>
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]8514
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]8515<div>
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]8516
8517<h5>Syntax:</h5>
8518<pre>
8519 declare void @llvm.trap()
8520</pre>
8521
8522<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8523<p>The '<tt>llvm.trap</tt>' intrinsic.</p>
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]8524
8525<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8526<p>None.</p>
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]8527
8528<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8529<p>This intrinsics is lowered to the target dependent trap instruction. If the
8530 target does not have a trap instruction, this intrinsic will be lowered to
8531 the call of the <tt>abort()</tt> function.</p>
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]8532
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]8533</div>
8534
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]8535<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8536<h4>
Misha Brukman50de2b22008-11-22 23:55:29 +0000[diff] [blame]8537 <a name="int_stackprotector">'<tt>llvm.stackprotector</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8538</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8539
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]8540<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8541
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]8542<h5>Syntax:</h5>
8543<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]8544 declare void @llvm.stackprotector(i8* &lt;guard&gt;, i8** &lt;slot&gt;)
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]8545</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8546
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]8547<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8548<p>The <tt>llvm.stackprotector</tt> intrinsic takes the <tt>guard</tt> and
8549 stores it onto the stack at <tt>slot</tt>. The stack slot is adjusted to
8550 ensure that it is placed on the stack before local variables.</p>
8551
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]8552<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8553<p>The <tt>llvm.stackprotector</tt> intrinsic requires two pointer
8554 arguments. The first argument is the value loaded from the stack
8555 guard <tt>@__stack_chk_guard</tt>. The second variable is an <tt>alloca</tt>
8556 that has enough space to hold the value of the guard.</p>
8557
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]8558<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8559<p>This intrinsic causes the prologue/epilogue inserter to force the position of
8560 the <tt>AllocaInst</tt> stack slot to be before local variables on the
8561 stack. This is to ensure that if a local variable on the stack is
8562 overwritten, it will destroy the value of the guard. When the function exits,
Bill Wendling6bbe0912010-10-27 01:07:41 +0000[diff] [blame]8563 the guard on the stack is checked against the original guard. If they are
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8564 different, then the program aborts by calling the <tt>__stack_chk_fail()</tt>
8565 function.</p>
8566
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]8567</div>
8568
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]8569<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8570<h4>
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]8571 <a name="int_objectsize">'<tt>llvm.objectsize</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8572</h4>
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]8573
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]8574<div>
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]8575
8576<h5>Syntax:</h5>
8577<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]8578 declare i32 @llvm.objectsize.i32(i8* &lt;object&gt;, i1 &lt;type&gt;)
8579 declare i64 @llvm.objectsize.i64(i8* &lt;object&gt;, i1 &lt;type&gt;)
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]8580</pre>
8581
8582<h5>Overview:</h5>
Bill Wendling6bbe0912010-10-27 01:07:41 +0000[diff] [blame]8583<p>The <tt>llvm.objectsize</tt> intrinsic is designed to provide information to
8584 the optimizers to determine at compile time whether a) an operation (like
8585 memcpy) will overflow a buffer that corresponds to an object, or b) that a
8586 runtime check for overflow isn't necessary. An object in this context means
8587 an allocation of a specific class, structure, array, or other object.</p>
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]8588
8589<h5>Arguments:</h5>
Bill Wendling6bbe0912010-10-27 01:07:41 +0000[diff] [blame]8590<p>The <tt>llvm.objectsize</tt> intrinsic takes two arguments. The first
Eric Christopher31e39bd2009-12-23 00:29:49 +0000[diff] [blame]8591 argument is a pointer to or into the <tt>object</tt>. The second argument
Bill Wendling6bbe0912010-10-27 01:07:41 +0000[diff] [blame]8592 is a boolean 0 or 1. This argument determines whether you want the
8593 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]8594 1, variables are not allowed.</p>
8595
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]8596<h5>Semantics:</h5>
8597<p>The <tt>llvm.objectsize</tt> intrinsic is lowered to either a constant
Bill Wendling6bbe0912010-10-27 01:07:41 +0000[diff] [blame]8598 representing the size of the object concerned, or <tt>i32/i64 -1 or 0</tt>,
8599 depending on the <tt>type</tt> argument, if the size cannot be determined at
8600 compile time.</p>
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]8601
8602</div>
8603
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]8604</div>
8605
8606</div>
8607
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]8608<!-- *********************************************************************** -->
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]8609<hr>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]8610<address>
8611 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
Misha Brukman86242e12008-12-11 17:34:48 +0000[diff] [blame]8612 src="http://jigsaw.w3.org/css-validator/images/vcss-blue" alt="Valid CSS"></a>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]8613 <a href="http://validator.w3.org/check/referer"><img
Misha Brukman86242e12008-12-11 17:34:48 +0000[diff] [blame]8614 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]8615
8616 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
NAKAMURA Takumica46f5a2011-04-09 02:13:37 +0000[diff] [blame]8617 <a href="http://llvm.org/">The LLVM Compiler Infrastructure</a><br>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]8618 Last modified: $Date$
8619</address>
Chris Lattnerb8f816e2008-01-04 04:33:49 +0000[diff] [blame]8620
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]8621</body>
8622</html>