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gerrit-public.fairphone.software / toolchain / llvm-project / ddfcec92d911ad00f099232d6b45fc848e8374d8 / . / 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.">
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11</head>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]12
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]13<body>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]14
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]15<h1>LLVM Language Reference Manual</h1>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]16<ol>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]17 <li><a href="#abstract">Abstract</a></li>
18 <li><a href="#introduction">Introduction</a></li>
19 <li><a href="#identifiers">Identifiers</a></li>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]20 <li><a href="#highlevel">High Level Structure</a>
21 <ol>
22 <li><a href="#modulestructure">Module Structure</a></li>
Bill Wendlinga3c6f6b2009-07-20 01:03:30 +0000[diff] [blame]23 <li><a href="#linkage">Linkage Types</a>
24 <ol>
Bill Wendling8693ef82009-07-20 02:41:50 +0000[diff] [blame]25 <li><a href="#linkage_private">'<tt>private</tt>' Linkage</a></li>
26 <li><a href="#linkage_linker_private">'<tt>linker_private</tt>' Linkage</a></li>
Bill Wendling03bcd6e2010-07-01 21:55:59 +0000[diff] [blame]27 <li><a href="#linkage_linker_private_weak">'<tt>linker_private_weak</tt>' Linkage</a></li>
Bill Wendling578ee402010-08-20 22:05:50 +0000[diff] [blame]28 <li><a href="#linkage_linker_private_weak_def_auto">'<tt>linker_private_weak_def_auto</tt>' Linkage</a></li>
Bill Wendling8693ef82009-07-20 02:41:50 +0000[diff] [blame]29 <li><a href="#linkage_internal">'<tt>internal</tt>' Linkage</a></li>
30 <li><a href="#linkage_available_externally">'<tt>available_externally</tt>' Linkage</a></li>
31 <li><a href="#linkage_linkonce">'<tt>linkonce</tt>' Linkage</a></li>
32 <li><a href="#linkage_common">'<tt>common</tt>' Linkage</a></li>
33 <li><a href="#linkage_weak">'<tt>weak</tt>' Linkage</a></li>
34 <li><a href="#linkage_appending">'<tt>appending</tt>' Linkage</a></li>
35 <li><a href="#linkage_externweak">'<tt>extern_weak</tt>' Linkage</a></li>
Chris Lattner80d73c72009-10-10 18:26:06 +0000[diff] [blame]36 <li><a href="#linkage_linkonce_odr">'<tt>linkonce_odr</tt>' Linkage</a></li>
Bill Wendling8693ef82009-07-20 02:41:50 +0000[diff] [blame]37 <li><a href="#linkage_weak">'<tt>weak_odr</tt>' Linkage</a></li>
38 <li><a href="#linkage_external">'<tt>externally visible</tt>' Linkage</a></li>
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
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]650 <dt><tt><b><a name="linkage_external">externally visible</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
683 other than "externally visible", <tt>dllimport</tt>
684 or <tt>extern_weak</tt>.</p>
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
Charles Davis22fe1862010-10-25 15:37:09 +0000[diff] [blame]1166 <dt><tt><b>hotpatch</b></tt></dt>
Charles Davis1b2d3722010-10-25 16:29:03 +0000[diff] [blame]1167 <dd>This attribute indicates that the function should be 'hotpatchable',
Charles Davis74205252010-10-25 19:07:39 +0000[diff] [blame]1168 meaning the function can be patched and/or hooked even while it is
1169 loaded into memory. On x86, the function prologue will be preceded
1170 by six bytes of padding and will begin with a two-byte instruction.
1171 Most of the functions in the Windows system DLLs in Windows XP SP2 or
1172 higher were compiled in this fashion.</dd>
Charles Davis22fe1862010-10-25 15:37:09 +0000[diff] [blame]1173
Dan Gohman8bd11f12011-06-16 16:03:13 +0000[diff] [blame]1174 <dt><tt><b>nonlazybind</b></tt></dt>
1175 <dd>This attribute suppresses lazy symbol binding for the function. This
1176 may make calls to the function faster, at the cost of extra program
1177 startup time if the function is not called during program startup.</dd>
1178
Jakob Stoklund Olesen74bb06c2010-02-06 01:16:28 +0000[diff] [blame]1179 <dt><tt><b>inlinehint</b></tt></dt>
1180 <dd>This attribute indicates that the source code contained a hint that inlining
1181 this function is desirable (such as the "inline" keyword in C/C++). It
1182 is just a hint; it imposes no requirements on the inliner.</dd>
1183
Nick Lewycky14b58da2010-07-06 18:24:09 +0000[diff] [blame]1184 <dt><tt><b>naked</b></tt></dt>
1185 <dd>This attribute disables prologue / epilogue emission for the function.
1186 This can have very system-specific consequences.</dd>
1187
1188 <dt><tt><b>noimplicitfloat</b></tt></dt>
1189 <dd>This attributes disables implicit floating point instructions.</dd>
1190
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1191 <dt><tt><b>noinline</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1192 <dd>This attribute indicates that the inliner should never inline this
1193 function in any situation. This attribute may not be used together with
1194 the <tt>alwaysinline</tt> attribute.</dd>
Devang Patel9eb525d2008-09-26 23:51:19 +0000[diff] [blame]1195
Nick Lewycky14b58da2010-07-06 18:24:09 +0000[diff] [blame]1196 <dt><tt><b>noredzone</b></tt></dt>
1197 <dd>This attribute indicates that the code generator should not use a red
1198 zone, even if the target-specific ABI normally permits it.</dd>
Devang Patel9eb525d2008-09-26 23:51:19 +0000[diff] [blame]1199
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1200 <dt><tt><b>noreturn</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1201 <dd>This function attribute indicates that the function never returns
1202 normally. This produces undefined behavior at runtime if the function
1203 ever does dynamically return.</dd>
Bill Wendlinga8130172008-11-13 01:02:51 +0000[diff] [blame]1204
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1205 <dt><tt><b>nounwind</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1206 <dd>This function attribute indicates that the function never returns with an
1207 unwind or exceptional control flow. If the function does unwind, its
1208 runtime behavior is undefined.</dd>
Bill Wendling0f5541e2008-11-26 19:07:40 +0000[diff] [blame]1209
Nick Lewycky14b58da2010-07-06 18:24:09 +0000[diff] [blame]1210 <dt><tt><b>optsize</b></tt></dt>
1211 <dd>This attribute suggests that optimization passes and code generator passes
1212 make choices that keep the code size of this function low, and otherwise
1213 do optimizations specifically to reduce code size.</dd>
1214
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1215 <dt><tt><b>readnone</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1216 <dd>This attribute indicates that the function computes its result (or decides
1217 to unwind an exception) based strictly on its arguments, without
1218 dereferencing any pointer arguments or otherwise accessing any mutable
1219 state (e.g. memory, control registers, etc) visible to caller functions.
1220 It does not write through any pointer arguments
1221 (including <tt><a href="#byval">byval</a></tt> arguments) and never
1222 changes any state visible to callers. This means that it cannot unwind
1223 exceptions by calling the <tt>C++</tt> exception throwing methods, but
1224 could use the <tt>unwind</tt> instruction.</dd>
Devang Patel310fd4a2009-06-12 19:45:19 +0000[diff] [blame]1225
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1226 <dt><tt><b><a name="readonly">readonly</a></b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1227 <dd>This attribute indicates that the function does not write through any
1228 pointer arguments (including <tt><a href="#byval">byval</a></tt>
1229 arguments) or otherwise modify any state (e.g. memory, control registers,
1230 etc) visible to caller functions. It may dereference pointer arguments
1231 and read state that may be set in the caller. A readonly function always
1232 returns the same value (or unwinds an exception identically) when called
1233 with the same set of arguments and global state. It cannot unwind an
1234 exception by calling the <tt>C++</tt> exception throwing methods, but may
1235 use the <tt>unwind</tt> instruction.</dd>
Anton Korobeynikovc8ce7b082009-07-17 18:07:26 +0000[diff] [blame]1236
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1237 <dt><tt><b><a name="ssp">ssp</a></b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1238 <dd>This attribute indicates that the function should emit a stack smashing
1239 protector. It is in the form of a "canary"&mdash;a random value placed on
1240 the stack before the local variables that's checked upon return from the
1241 function to see if it has been overwritten. A heuristic is used to
1242 determine if a function needs stack protectors or not.<br>
1243<br>
1244 If a function that has an <tt>ssp</tt> attribute is inlined into a
1245 function that doesn't have an <tt>ssp</tt> attribute, then the resulting
1246 function will have an <tt>ssp</tt> attribute.</dd>
1247
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1248 <dt><tt><b>sspreq</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1249 <dd>This attribute indicates that the function should <em>always</em> emit a
1250 stack smashing protector. This overrides
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1251 the <tt><a href="#ssp">ssp</a></tt> function attribute.<br>
1252<br>
1253 If a function that has an <tt>sspreq</tt> attribute is inlined into a
1254 function that doesn't have an <tt>sspreq</tt> attribute or which has
1255 an <tt>ssp</tt> attribute, then the resulting function will have
1256 an <tt>sspreq</tt> attribute.</dd>
Rafael Espindola163d6752011-07-25 15:27:59 +0000[diff] [blame]1257
1258 <dt><tt><b><a name="uwtable">uwtable</a></b></tt></dt>
1259 <dd>This attribute indicates that the ABI being targeted requires that
1260 an unwind table entry be produce for this function even if we can
1261 show that no exceptions passes by it. This is normally the case for
1262 the ELF x86-64 abi, but it can be disabled for some compilation
1263 units.</dd>
1264
Bill Wendlingb175fa42008-09-07 10:26:33 +0000[diff] [blame]1265</dl>
1266
Devang Patelcaacdba2008-09-04 23:05:13 +0000[diff] [blame]1267</div>
1268
1269<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1270<h3>
Chris Lattner93564892006-04-08 04:40:53 +0000[diff] [blame]1271 <a name="moduleasm">Module-Level Inline Assembly</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1272</h3>
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]1273
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1274<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1275
1276<p>Modules may contain "module-level inline asm" blocks, which corresponds to
1277 the GCC "file scope inline asm" blocks. These blocks are internally
1278 concatenated by LLVM and treated as a single unit, but may be separated in
1279 the <tt>.ll</tt> file if desired. The syntax is very simple:</p>
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]1280
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]1281<pre class="doc_code">
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]1282module asm "inline asm code goes here"
1283module asm "more can go here"
1284</pre>
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]1285
1286<p>The strings can contain any character by escaping non-printable characters.
1287 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]1288 for the number.</p>
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]1289
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1290<p>The inline asm code is simply printed to the machine code .s file when
1291 assembly code is generated.</p>
1292
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]1293</div>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]1294
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1295<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1296<h3>
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1297 <a name="datalayout">Data Layout</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1298</h3>
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1299
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1300<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1301
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1302<p>A module may specify a target specific data layout string that specifies how
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1303 data is to be laid out in memory. The syntax for the data layout is
1304 simply:</p>
1305
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]1306<pre class="doc_code">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1307target datalayout = "<i>layout specification</i>"
1308</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1309
1310<p>The <i>layout specification</i> consists of a list of specifications
1311 separated by the minus sign character ('-'). Each specification starts with
1312 a letter and may include other information after the letter to define some
1313 aspect of the data layout. The specifications accepted are as follows:</p>
1314
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1315<dl>
1316 <dt><tt>E</tt></dt>
1317 <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]1318 bits with the most significance have the lowest address location.</dd>
1319
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1320 <dt><tt>e</tt></dt>
Chris Lattner67c37d12008-08-05 18:29:16 +0000[diff] [blame]1321 <dd>Specifies that the target lays out data in little-endian form. That is,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1322 the bits with the least significance have the lowest address
1323 location.</dd>
1324
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1325 <dt><tt>p:<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]1326 <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]1327 <i>preferred</i> alignments. All sizes are in bits. Specifying
1328 the <i>pref</i> alignment is optional. If omitted, the
1329 preceding <tt>:</tt> should be omitted too.</dd>
1330
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1331 <dt><tt>i<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1332 <dd>This specifies the alignment for an integer type of a given bit
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1333 <i>size</i>. The value of <i>size</i> must be in the range [1,2^23).</dd>
1334
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1335 <dt><tt>v<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]1336 <dd>This specifies the alignment for a vector type of a given bit
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1337 <i>size</i>.</dd>
1338
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1339 <dt><tt>f<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 floating point type of a given bit
Dale Johannesence522852010-05-28 18:54:47 +0000[diff] [blame]1341 <i>size</i>. Only values of <i>size</i> that are supported by the target
1342 will work. 32 (float) and 64 (double) are supported on all targets;
1343 80 or 128 (different flavors of long double) are also supported on some
1344 targets.
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1345
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1346 <dt><tt>a<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1347 <dd>This specifies the alignment for an aggregate type of a given bit
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1348 <i>size</i>.</dd>
1349
Daniel Dunbar7921a592009-06-08 22:17:53 +0000[diff] [blame]1350 <dt><tt>s<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1351 <dd>This specifies the alignment for a stack object of a given bit
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1352 <i>size</i>.</dd>
Chris Lattnera381eff2009-11-07 09:35:34 +0000[diff] [blame]1353
1354 <dt><tt>n<i>size1</i>:<i>size2</i>:<i>size3</i>...</tt></dt>
1355 <dd>This specifies a set of native integer widths for the target CPU
1356 in bits. For example, it might contain "n32" for 32-bit PowerPC,
1357 "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]1358 this set are considered to support most general arithmetic
Chris Lattnera381eff2009-11-07 09:35:34 +0000[diff] [blame]1359 operations efficiently.</dd>
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1360</dl>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1361
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1362<p>When constructing the data layout for a given target, LLVM starts with a
Dan Gohman61110ae2010-04-28 00:36:01 +0000[diff] [blame]1363 default set of specifications which are then (possibly) overridden by the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1364 specifications in the <tt>datalayout</tt> keyword. The default specifications
1365 are given in this list:</p>
1366
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1367<ul>
1368 <li><tt>E</tt> - big endian</li>
Dan Gohman8ad777d2010-02-23 02:44:03 +0000[diff] [blame]1369 <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]1370 <li><tt>i1:8:8</tt> - i1 is 8-bit (byte) aligned</li>
1371 <li><tt>i8:8:8</tt> - i8 is 8-bit (byte) aligned</li>
1372 <li><tt>i16:16:16</tt> - i16 is 16-bit aligned</li>
1373 <li><tt>i32:32:32</tt> - i32 is 32-bit aligned</li>
Chris Lattner67c37d12008-08-05 18:29:16 +0000[diff] [blame]1374 <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]1375 alignment of 64-bits</li>
1376 <li><tt>f32:32:32</tt> - float is 32-bit aligned</li>
1377 <li><tt>f64:64:64</tt> - double is 64-bit aligned</li>
1378 <li><tt>v64:64:64</tt> - 64-bit vector is 64-bit aligned</li>
1379 <li><tt>v128:128:128</tt> - 128-bit vector is 128-bit aligned</li>
1380 <li><tt>a0:0:1</tt> - aggregates are 8-bit aligned</li>
Daniel Dunbar7921a592009-06-08 22:17:53 +0000[diff] [blame]1381 <li><tt>s0:64:64</tt> - stack objects are 64-bit aligned</li>
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1382</ul>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1383
1384<p>When LLVM is determining the alignment for a given type, it uses the
1385 following rules:</p>
1386
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1387<ol>
1388 <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]1389 specification is used.</li>
1390
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1391 <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]1392 smallest integer type that is larger than the bitwidth of the sought type
1393 is used. If none of the specifications are larger than the bitwidth then
1394 the the largest integer type is used. For example, given the default
1395 specifications above, the i7 type will use the alignment of i8 (next
1396 largest) while both i65 and i256 will use the alignment of i64 (largest
1397 specified).</li>
1398
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1399 <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]1400 largest vector type that is smaller than the sought vector type will be
1401 used as a fall back. This happens because &lt;128 x double&gt; can be
1402 implemented in terms of 64 &lt;2 x double&gt;, for example.</li>
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1403</ol>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1404
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1405</div>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]1406
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1407<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1408<h3>
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1409 <a name="pointeraliasing">Pointer Aliasing Rules</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1410</h3>
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1411
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1412<div>
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1413
Andreas Bolka8ae4e242009-07-29 00:02:05 +0000[diff] [blame]1414<p>Any memory access must be done through a pointer value associated
Andreas Bolkae39f0332009-07-27 20:37:10 +0000[diff] [blame]1415with an address range of the memory access, otherwise the behavior
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1416is undefined. Pointer values are associated with address ranges
1417according to the following rules:</p>
1418
1419<ul>
Dan Gohmandf12d082010-07-02 18:41:32 +0000[diff] [blame]1420 <li>A pointer value is associated with the addresses associated with
1421 any value it is <i>based</i> on.
Andreas Bolka8ae4e242009-07-29 00:02:05 +0000[diff] [blame]1422 <li>An address of a global variable is associated with the address
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1423 range of the variable's storage.</li>
1424 <li>The result value of an allocation instruction is associated with
1425 the address range of the allocated storage.</li>
1426 <li>A null pointer in the default address-space is associated with
Andreas Bolka8ae4e242009-07-29 00:02:05 +0000[diff] [blame]1427 no address.</li>
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1428 <li>An integer constant other than zero or a pointer value returned
1429 from a function not defined within LLVM may be associated with address
1430 ranges allocated through mechanisms other than those provided by
Andreas Bolka8ae4e242009-07-29 00:02:05 +0000[diff] [blame]1431 LLVM. Such ranges shall not overlap with any ranges of addresses
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1432 allocated by mechanisms provided by LLVM.</li>
Dan Gohmandf12d082010-07-02 18:41:32 +0000[diff] [blame]1433</ul>
1434
1435<p>A pointer value is <i>based</i> on another pointer value according
1436 to the following rules:</p>
1437
1438<ul>
1439 <li>A pointer value formed from a
1440 <tt><a href="#i_getelementptr">getelementptr</a></tt> operation
1441 is <i>based</i> on the first operand of the <tt>getelementptr</tt>.</li>
1442 <li>The result value of a
1443 <tt><a href="#i_bitcast">bitcast</a></tt> is <i>based</i> on the operand
1444 of the <tt>bitcast</tt>.</li>
1445 <li>A pointer value formed by an
1446 <tt><a href="#i_inttoptr">inttoptr</a></tt> is <i>based</i> on all
1447 pointer values that contribute (directly or indirectly) to the
1448 computation of the pointer's value.</li>
1449 <li>The "<i>based</i> on" relationship is transitive.</li>
1450</ul>
1451
1452<p>Note that this definition of <i>"based"</i> is intentionally
1453 similar to the definition of <i>"based"</i> in C99, though it is
1454 slightly weaker.</p>
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1455
1456<p>LLVM IR does not associate types with memory. The result type of a
Andreas Bolka8ae4e242009-07-29 00:02:05 +0000[diff] [blame]1457<tt><a href="#i_load">load</a></tt> merely indicates the size and
1458alignment of the memory from which to load, as well as the
Dan Gohman4eb47192010-06-17 19:23:50 +0000[diff] [blame]1459interpretation of the value. The first operand type of a
Andreas Bolka8ae4e242009-07-29 00:02:05 +0000[diff] [blame]1460<tt><a href="#i_store">store</a></tt> similarly only indicates the size
1461and alignment of the store.</p>
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1462
1463<p>Consequently, type-based alias analysis, aka TBAA, aka
1464<tt>-fstrict-aliasing</tt>, is not applicable to general unadorned
1465LLVM IR. <a href="#metadata">Metadata</a> may be used to encode
1466additional information which specialized optimization passes may use
1467to implement type-based alias analysis.</p>
1468
1469</div>
1470
Jeffrey Yasskin5d284ae2010-04-26 21:21:24 +0000[diff] [blame]1471<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1472<h3>
Jeffrey Yasskin5d284ae2010-04-26 21:21:24 +0000[diff] [blame]1473 <a name="volatile">Volatile Memory Accesses</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1474</h3>
Jeffrey Yasskin5d284ae2010-04-26 21:21:24 +0000[diff] [blame]1475
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1476<div>
Jeffrey Yasskin5d284ae2010-04-26 21:21:24 +0000[diff] [blame]1477
1478<p>Certain memory accesses, such as <a href="#i_load"><tt>load</tt></a>s, <a
1479href="#i_store"><tt>store</tt></a>s, and <a
1480href="#int_memcpy"><tt>llvm.memcpy</tt></a>s may be marked <tt>volatile</tt>.
1481The optimizers must not change the number of volatile operations or change their
1482order of execution relative to other volatile operations. The optimizers
1483<i>may</i> change the order of volatile operations relative to non-volatile
1484operations. This is not Java's "volatile" and has no cross-thread
1485synchronization behavior.</p>
1486
1487</div>
1488
Eli Friedman35b54aa2011-07-20 21:35:53 +0000[diff] [blame]1489<!-- ======================================================================= -->
1490<h3>
1491 <a name="memmodel">Memory Model for Concurrent Operations</a>
1492</h3>
1493
1494<div>
1495
1496<p>The LLVM IR does not define any way to start parallel threads of execution
1497or to register signal handlers. Nonetheless, there are platform-specific
1498ways to create them, and we define LLVM IR's behavior in their presence. This
1499model is inspired by the C++0x memory model.</p>
1500
Eli Friedman95f69a42011-08-22 21:35:27 +0000[diff] [blame]1501<p>For a more informal introduction to this model, see the
1502<a href="Atomics.html">LLVM Atomic Instructions and Concurrency Guide</a>.
1503
Eli Friedman35b54aa2011-07-20 21:35:53 +0000[diff] [blame]1504<p>We define a <i>happens-before</i> partial order as the least partial order
1505that</p>
1506<ul>
1507 <li>Is a superset of single-thread program order, and</li>
1508 <li>When a <i>synchronizes-with</i> <tt>b</tt>, includes an edge from
1509 <tt>a</tt> to <tt>b</tt>. <i>Synchronizes-with</i> pairs are introduced
1510 by platform-specific techniques, like pthread locks, thread
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]1511 creation, thread joining, etc., and by atomic instructions.
1512 (See also <a href="#ordering">Atomic Memory Ordering Constraints</a>).
1513 </li>
Eli Friedman35b54aa2011-07-20 21:35:53 +0000[diff] [blame]1514</ul>
1515
1516<p>Note that program order does not introduce <i>happens-before</i> edges
1517between a thread and signals executing inside that thread.</p>
1518
1519<p>Every (defined) read operation (load instructions, memcpy, atomic
1520loads/read-modify-writes, etc.) <var>R</var> reads a series of bytes written by
1521(defined) write operations (store instructions, atomic
Eli Friedmanf12e4e92011-07-22 03:04:45 +0000[diff] [blame]1522stores/read-modify-writes, memcpy, etc.). For the purposes of this section,
1523initialized globals are considered to have a write of the initializer which is
1524atomic and happens before any other read or write of the memory in question.
1525For each byte of a read <var>R</var>, <var>R<sub>byte</sub></var> may see
1526any write to the same byte, except:</p>
Eli Friedman35b54aa2011-07-20 21:35:53 +0000[diff] [blame]1527
1528<ul>
1529 <li>If <var>write<sub>1</sub></var> happens before
1530 <var>write<sub>2</sub></var>, and <var>write<sub>2</sub></var> happens
1531 before <var>R<sub>byte</sub></var>, then <var>R<sub>byte</sub></var>
Eli Friedmanf12e4e92011-07-22 03:04:45 +0000[diff] [blame]1532 does not see <var>write<sub>1</sub></var>.
Bill Wendling537603b2011-07-31 06:45:03 +0000[diff] [blame]1533 <li>If <var>R<sub>byte</sub></var> happens before
1534 <var>write<sub>3</sub></var>, then <var>R<sub>byte</sub></var> does not
1535 see <var>write<sub>3</sub></var>.
Eli Friedman35b54aa2011-07-20 21:35:53 +0000[diff] [blame]1536</ul>
1537
1538<p>Given that definition, <var>R<sub>byte</sub></var> is defined as follows:
1539<ul>
Eli Friedman95f69a42011-08-22 21:35:27 +0000[diff] [blame]1540 <li>If <var>R</var> is volatile, the result is target-dependent. (Volatile
1541 is supposed to give guarantees which can support
1542 <code>sig_atomic_t</code> in C/C++, and may be used for accesses to
1543 addresses which do not behave like normal memory. It does not generally
1544 provide cross-thread synchronization.)
1545 <li>Otherwise, if there is no write to the same byte that happens before
Eli Friedman35b54aa2011-07-20 21:35:53 +0000[diff] [blame]1546 <var>R<sub>byte</sub></var>, <var>R<sub>byte</sub></var> returns
1547 <tt>undef</tt> for that byte.
Eli Friedmanf12e4e92011-07-22 03:04:45 +0000[diff] [blame]1548 <li>Otherwise, if <var>R<sub>byte</sub></var> may see exactly one write,
Eli Friedman35b54aa2011-07-20 21:35:53 +0000[diff] [blame]1549 <var>R<sub>byte</sub></var> returns the value written by that
1550 write.</li>
Eli Friedmanf12e4e92011-07-22 03:04:45 +0000[diff] [blame]1551 <li>Otherwise, if <var>R</var> is atomic, and all the writes
1552 <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]1553 values written. See the <a href="#ordering">Atomic Memory Ordering
1554 Constraints</a> section for additional constraints on how the choice
1555 is made.
Eli Friedman35b54aa2011-07-20 21:35:53 +0000[diff] [blame]1556 <li>Otherwise <var>R<sub>byte</sub></var> returns <tt>undef</tt>.</li>
1557</ul>
1558
1559<p><var>R</var> returns the value composed of the series of bytes it read.
1560This implies that some bytes within the value may be <tt>undef</tt>
1561<b>without</b> the entire value being <tt>undef</tt>. Note that this only
1562defines the semantics of the operation; it doesn't mean that targets will
1563emit more than one instruction to read the series of bytes.</p>
1564
1565<p>Note that in cases where none of the atomic intrinsics are used, this model
1566places only one restriction on IR transformations on top of what is required
1567for single-threaded execution: introducing a store to a byte which might not
Eli Friedman4bc9f3c2011-08-02 01:15:34 +0000[diff] [blame]1568otherwise be stored is not allowed in general. (Specifically, in the case
1569where another thread might write to and read from an address, introducing a
1570store can change a load that may see exactly one write into a load that may
1571see multiple writes.)</p>
Eli Friedman35b54aa2011-07-20 21:35:53 +0000[diff] [blame]1572
1573<!-- FIXME: This model assumes all targets where concurrency is relevant have
1574a byte-size store which doesn't affect adjacent bytes. As far as I can tell,
1575none of the backends currently in the tree fall into this category; however,
1576there might be targets which care. If there are, we want a paragraph
1577like the following:
1578
1579Targets may specify that stores narrower than a certain width are not
1580available; on such a target, for the purposes of this model, treat any
1581non-atomic write with an alignment or width less than the minimum width
1582as if it writes to the relevant surrounding bytes.
1583-->
1584
1585</div>
1586
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]1587<!-- ======================================================================= -->
NAKAMURA Takumi0300d882011-08-12 06:17:17 +0000[diff] [blame]1588<h3>
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]1589 <a name="ordering">Atomic Memory Ordering Constraints</a>
NAKAMURA Takumi0300d882011-08-12 06:17:17 +0000[diff] [blame]1590</h3>
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]1591
NAKAMURA Takumi0300d882011-08-12 06:17:17 +0000[diff] [blame]1592<div>
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]1593
1594<p>Atomic instructions (<a href="#i_cmpxchg"><code>cmpxchg</code></a>,
Eli Friedman59b66882011-08-09 23:02:53 +0000[diff] [blame]1595<a href="#i_atomicrmw"><code>atomicrmw</code></a>,
1596<a href="#i_fence"><code>fence</code></a>,
1597<a href="#i_load"><code>atomic load</code></a>, and
Eli Friedman75362532011-08-09 23:26:12 +0000[diff] [blame]1598<a href="#i_store"><code>atomic store</code></a>) take an ordering parameter
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]1599that determines which other atomic instructions on the same address they
1600<i>synchronize with</i>. These semantics are borrowed from Java and C++0x,
1601but are somewhat more colloquial. If these descriptions aren't precise enough,
Eli Friedman95f69a42011-08-22 21:35:27 +0000[diff] [blame]1602check those specs (see spec references in the
1603<a href="Atomic.html#introduction">atomics guide</a>).
1604<a href="#i_fence"><code>fence</code></a> instructions
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]1605treat these orderings somewhat differently since they don't take an address.
1606See that instruction's documentation for details.</p>
1607
Eli Friedman95f69a42011-08-22 21:35:27 +0000[diff] [blame]1608<p>For a simpler introduction to the ordering constraints, see the
1609<a href="Atomics.html">LLVM Atomic Instructions and Concurrency Guide</a>.</p>
1610
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]1611<dl>
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]1612<dt><code>unordered</code></dt>
1613<dd>The set of values that can be read is governed by the happens-before
1614partial order. A value cannot be read unless some operation wrote it.
1615This is intended to provide a guarantee strong enough to model Java's
1616non-volatile shared variables. This ordering cannot be specified for
1617read-modify-write operations; it is not strong enough to make them atomic
1618in any interesting way.</dd>
1619<dt><code>monotonic</code></dt>
1620<dd>In addition to the guarantees of <code>unordered</code>, there is a single
1621total order for modifications by <code>monotonic</code> operations on each
1622address. All modification orders must be compatible with the happens-before
1623order. There is no guarantee that the modification orders can be combined to
1624a global total order for the whole program (and this often will not be
1625possible). The read in an atomic read-modify-write operation
1626(<a href="#i_cmpxchg"><code>cmpxchg</code></a> and
1627<a href="#i_atomicrmw"><code>atomicrmw</code></a>)
1628reads the value in the modification order immediately before the value it
1629writes. If one atomic read happens before another atomic read of the same
1630address, the later read must see the same value or a later value in the
1631address's modification order. This disallows reordering of
1632<code>monotonic</code> (or stronger) operations on the same address. If an
1633address is written <code>monotonic</code>ally by one thread, and other threads
1634<code>monotonic</code>ally read that address repeatedly, the other threads must
Eli Friedman95f69a42011-08-22 21:35:27 +0000[diff] [blame]1635eventually see the write. This corresponds to the C++0x/C1x
1636<code>memory_order_relaxed</code>.</dd>
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]1637<dt><code>acquire</code></dt>
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]1638<dd>In addition to the guarantees of <code>monotonic</code>,
Eli Friedman0cb3b562011-08-24 20:28:39 +0000[diff] [blame]1639a <i>synchronizes-with</i> edge may be formed with a <code>release</code>
1640operation. This is intended to model C++'s <code>memory_order_acquire</code>.</dd>
1641<dt><code>release</code></dt>
1642<dd>In addition to the guarantees of <code>monotonic</code>, if this operation
1643writes a value which is subsequently read by an <code>acquire</code> operation,
1644it <i>synchronizes-with</i> that operation. (This isn't a complete
1645description; see the C++0x definition of a release sequence.) This corresponds
1646to the C++0x/C1x <code>memory_order_release</code>.</dd>
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]1647<dt><code>acq_rel</code> (acquire+release)</dt><dd>Acts as both an
Eli Friedman95f69a42011-08-22 21:35:27 +0000[diff] [blame]1648<code>acquire</code> and <code>release</code> operation on its address.
1649This corresponds to the C++0x/C1x <code>memory_order_acq_rel</code>.</dd>
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]1650<dt><code>seq_cst</code> (sequentially consistent)</dt><dd>
1651<dd>In addition to the guarantees of <code>acq_rel</code>
1652(<code>acquire</code> for an operation which only reads, <code>release</code>
1653for an operation which only writes), there is a global total order on all
1654sequentially-consistent operations on all addresses, which is consistent with
1655the <i>happens-before</i> partial order and with the modification orders of
1656all the affected addresses. Each sequentially-consistent read sees the last
Eli Friedman95f69a42011-08-22 21:35:27 +0000[diff] [blame]1657preceding write to the same address in this global order. This corresponds
1658to the C++0x/C1x <code>memory_order_seq_cst</code> and Java volatile.</dd>
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]1659</dl>
1660
1661<p id="singlethread">If an atomic operation is marked <code>singlethread</code>,
1662it only <i>synchronizes with</i> or participates in modification and seq_cst
1663total orderings with other operations running in the same thread (for example,
1664in signal handlers).</p>
1665
1666</div>
1667
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1668</div>
1669
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1670<!-- *********************************************************************** -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1671<h2><a name="typesystem">Type System</a></h2>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1672<!-- *********************************************************************** -->
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]1673
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1674<div>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]1675
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1676<p>The LLVM type system is one of the most important features of the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1677 intermediate representation. Being typed enables a number of optimizations
1678 to be performed on the intermediate representation directly, without having
1679 to do extra analyses on the side before the transformation. A strong type
1680 system makes it easier to read the generated code and enables novel analyses
1681 and transformations that are not feasible to perform on normal three address
1682 code representations.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]1683
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1684<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1685<h3>
1686 <a name="t_classifications">Type Classifications</a>
1687</h3>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1688
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1689<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1690
1691<p>The types fall into a few useful classifications:</p>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]1692
1693<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1694 <tbody>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1695 <tr><th>Classification</th><th>Types</th></tr>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1696 <tr>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1697 <td><a href="#t_integer">integer</a></td>
Reid Spencer138249b2007-05-16 18:44:01 +0000[diff] [blame]1698 <td><tt>i1, i2, i3, ... i8, ... i16, ... i32, ... i64, ... </tt></td>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1699 </tr>
1700 <tr>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1701 <td><a href="#t_floating">floating point</a></td>
1702 <td><tt>float, double, x86_fp80, fp128, ppc_fp128</tt></td>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1703 </tr>
1704 <tr>
1705 <td><a name="t_firstclass">first class</a></td>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1706 <td><a href="#t_integer">integer</a>,
1707 <a href="#t_floating">floating point</a>,
1708 <a href="#t_pointer">pointer</a>,
Dan Gohman08783a882008-06-18 18:42:13 +0000[diff] [blame]1709 <a href="#t_vector">vector</a>,
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]1710 <a href="#t_struct">structure</a>,
1711 <a href="#t_array">array</a>,
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1712 <a href="#t_label">label</a>,
1713 <a href="#t_metadata">metadata</a>.
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1714 </td>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1715 </tr>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1716 <tr>
1717 <td><a href="#t_primitive">primitive</a></td>
1718 <td><a href="#t_label">label</a>,
1719 <a href="#t_void">void</a>,
Tobias Grosser4c8c95b2010-12-28 20:29:31 +0000[diff] [blame]1720 <a href="#t_integer">integer</a>,
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1721 <a href="#t_floating">floating point</a>,
Dale Johannesen33e5c352010-10-01 00:48:59 +0000[diff] [blame]1722 <a href="#t_x86mmx">x86mmx</a>,
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1723 <a href="#t_metadata">metadata</a>.</td>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1724 </tr>
1725 <tr>
1726 <td><a href="#t_derived">derived</a></td>
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]1727 <td><a href="#t_array">array</a>,
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1728 <a href="#t_function">function</a>,
1729 <a href="#t_pointer">pointer</a>,
1730 <a href="#t_struct">structure</a>,
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1731 <a href="#t_vector">vector</a>,
1732 <a href="#t_opaque">opaque</a>.
Dan Gohman93bf60d2008-10-14 16:32:04 +0000[diff] [blame]1733 </td>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1734 </tr>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1735 </tbody>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1736</table>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]1737
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1738<p>The <a href="#t_firstclass">first class</a> types are perhaps the most
1739 important. Values of these types are the only ones which can be produced by
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]1740 instructions.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1741
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1742</div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1743
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1744<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1745<h3>
1746 <a name="t_primitive">Primitive Types</a>
1747</h3>
Chris Lattner43542b32008-01-04 04:34:14 +0000[diff] [blame]1748
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1749<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1750
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1751<p>The primitive types are the fundamental building blocks of the LLVM
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1752 system.</p>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1753
1754<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1755<h4>
1756 <a name="t_integer">Integer Type</a>
1757</h4>
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]1758
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1759<div>
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]1760
1761<h5>Overview:</h5>
1762<p>The integer type is a very simple type that simply specifies an arbitrary
1763 bit width for the integer type desired. Any bit width from 1 bit to
1764 2<sup>23</sup>-1 (about 8 million) can be specified.</p>
1765
1766<h5>Syntax:</h5>
1767<pre>
1768 iN
1769</pre>
1770
1771<p>The number of bits the integer will occupy is specified by the <tt>N</tt>
1772 value.</p>
1773
1774<h5>Examples:</h5>
1775<table class="layout">
1776 <tr class="layout">
1777 <td class="left"><tt>i1</tt></td>
1778 <td class="left">a single-bit integer.</td>
1779 </tr>
1780 <tr class="layout">
1781 <td class="left"><tt>i32</tt></td>
1782 <td class="left">a 32-bit integer.</td>
1783 </tr>
1784 <tr class="layout">
1785 <td class="left"><tt>i1942652</tt></td>
1786 <td class="left">a really big integer of over 1 million bits.</td>
1787 </tr>
1788</table>
1789
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]1790</div>
1791
1792<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1793<h4>
1794 <a name="t_floating">Floating Point Types</a>
1795</h4>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1796
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1797<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1798
1799<table>
1800 <tbody>
1801 <tr><th>Type</th><th>Description</th></tr>
1802 <tr><td><tt>float</tt></td><td>32-bit floating point value</td></tr>
1803 <tr><td><tt>double</tt></td><td>64-bit floating point value</td></tr>
1804 <tr><td><tt>fp128</tt></td><td>128-bit floating point value (112-bit mantissa)</td></tr>
1805 <tr><td><tt>x86_fp80</tt></td><td>80-bit floating point value (X87)</td></tr>
1806 <tr><td><tt>ppc_fp128</tt></td><td>128-bit floating point value (two 64-bits)</td></tr>
1807 </tbody>
1808</table>
1809
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1810</div>
1811
1812<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1813<h4>
1814 <a name="t_x86mmx">X86mmx Type</a>
1815</h4>
Dale Johannesen33e5c352010-10-01 00:48:59 +0000[diff] [blame]1816
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1817<div>
Dale Johannesen33e5c352010-10-01 00:48:59 +0000[diff] [blame]1818
1819<h5>Overview:</h5>
1820<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>
1821
1822<h5>Syntax:</h5>
1823<pre>
Dale Johannesenb1f0ff12010-10-01 01:07:02 +0000[diff] [blame]1824 x86mmx
Dale Johannesen33e5c352010-10-01 00:48:59 +0000[diff] [blame]1825</pre>
1826
1827</div>
1828
1829<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1830<h4>
1831 <a name="t_void">Void Type</a>
1832</h4>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1833
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1834<div>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1835
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1836<h5>Overview:</h5>
1837<p>The void type does not represent any value and has no size.</p>
1838
1839<h5>Syntax:</h5>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1840<pre>
1841 void
1842</pre>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1843
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1844</div>
1845
1846<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1847<h4>
1848 <a name="t_label">Label Type</a>
1849</h4>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1850
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1851<div>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1852
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1853<h5>Overview:</h5>
1854<p>The label type represents code labels.</p>
1855
1856<h5>Syntax:</h5>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1857<pre>
1858 label
1859</pre>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1860
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1861</div>
1862
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1863<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1864<h4>
1865 <a name="t_metadata">Metadata Type</a>
1866</h4>
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1867
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1868<div>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1869
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1870<h5>Overview:</h5>
Nick Lewycky93e06a52009-09-27 23:27:42 +0000[diff] [blame]1871<p>The metadata type represents embedded metadata. No derived types may be
1872 created from metadata except for <a href="#t_function">function</a>
1873 arguments.
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1874
1875<h5>Syntax:</h5>
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1876<pre>
1877 metadata
1878</pre>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1879
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1880</div>
1881
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1882</div>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1883
1884<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1885<h3>
1886 <a name="t_derived">Derived Types</a>
1887</h3>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1888
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1889<div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1890
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1891<p>The real power in LLVM comes from the derived types in the system. This is
1892 what allows a programmer to represent arrays, functions, pointers, and other
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]1893 useful types. Each of these types contain one or more element types which
1894 may be a primitive type, or another derived type. For example, it is
1895 possible to have a two dimensional array, using an array as the element type
1896 of another array.</p>
Dan Gohman142ccc02009-01-24 15:58:40 +0000[diff] [blame]1897
Chris Lattnerb1ed91f2011-07-09 17:41:24 +0000[diff] [blame]1898</div>
1899
1900
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]1901<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1902<h4>
1903 <a name="t_aggregate">Aggregate Types</a>
1904</h4>
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]1905
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1906<div>
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]1907
1908<p>Aggregate Types are a subset of derived types that can contain multiple
1909 member types. <a href="#t_array">Arrays</a>,
Chris Lattner13ee7952010-08-28 04:09:24 +0000[diff] [blame]1910 <a href="#t_struct">structs</a>, and <a href="#t_vector">vectors</a> are
1911 aggregate types.</p>
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]1912
1913</div>
1914
Reid Spencer138249b2007-05-16 18:44:01 +0000[diff] [blame]1915<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1916<h4>
1917 <a name="t_array">Array Type</a>
1918</h4>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1919
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1920<div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1921
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1922<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1923<p>The array type is a very simple derived type that arranges elements
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1924 sequentially in memory. The array type requires a size (number of elements)
1925 and an underlying data type.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1926
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]1927<h5>Syntax:</h5>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1928<pre>
1929 [&lt;# elements&gt; x &lt;elementtype&gt;]
1930</pre>
1931
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1932<p>The number of elements is a constant integer value; <tt>elementtype</tt> may
1933 be any type with a size.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1934
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]1935<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1936<table class="layout">
1937 <tr class="layout">
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]1938 <td class="left"><tt>[40 x i32]</tt></td>
1939 <td class="left">Array of 40 32-bit integer values.</td>
1940 </tr>
1941 <tr class="layout">
1942 <td class="left"><tt>[41 x i32]</tt></td>
1943 <td class="left">Array of 41 32-bit integer values.</td>
1944 </tr>
1945 <tr class="layout">
1946 <td class="left"><tt>[4 x i8]</tt></td>
1947 <td class="left">Array of 4 8-bit integer values.</td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1948 </tr>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1949</table>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1950<p>Here are some examples of multidimensional arrays:</p>
1951<table class="layout">
1952 <tr class="layout">
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]1953 <td class="left"><tt>[3 x [4 x i32]]</tt></td>
1954 <td class="left">3x4 array of 32-bit integer values.</td>
1955 </tr>
1956 <tr class="layout">
1957 <td class="left"><tt>[12 x [10 x float]]</tt></td>
1958 <td class="left">12x10 array of single precision floating point values.</td>
1959 </tr>
1960 <tr class="layout">
1961 <td class="left"><tt>[2 x [3 x [4 x i16]]]</tt></td>
1962 <td class="left">2x3x4 array of 16-bit integer values.</td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1963 </tr>
1964</table>
Chris Lattnerc0ad71e2005-06-24 17:22:57 +0000[diff] [blame]1965
Dan Gohmanc74bc282009-11-09 19:01:53 +0000[diff] [blame]1966<p>There is no restriction on indexing beyond the end of the array implied by
1967 a static type (though there are restrictions on indexing beyond the bounds
1968 of an allocated object in some cases). This means that single-dimension
1969 'variable sized array' addressing can be implemented in LLVM with a zero
1970 length array type. An implementation of 'pascal style arrays' in LLVM could
1971 use the type "<tt>{ i32, [0 x float]}</tt>", for example.</p>
Chris Lattnerc0ad71e2005-06-24 17:22:57 +0000[diff] [blame]1972
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1973</div>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1974
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1975<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1976<h4>
1977 <a name="t_function">Function Type</a>
1978</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1979
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1980<div>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]1981
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1982<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1983<p>The function type can be thought of as a function signature. It consists of
1984 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]1985 function type is a first class type or a void type.</p>
Devang Pateld6cff512008-03-10 20:49:15 +0000[diff] [blame]1986
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1987<h5>Syntax:</h5>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]1988<pre>
Nick Lewycky14d1ccc2009-09-27 07:55:32 +0000[diff] [blame]1989 &lt;returntype&gt; (&lt;parameter list&gt;)
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]1990</pre>
1991
John Criswell4c0cf7f2005-10-24 16:17:18 +0000[diff] [blame]1992<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]1993 specifiers. Optionally, the parameter list may include a type <tt>...</tt>,
1994 which indicates that the function takes a variable number of arguments.
1995 Variable argument functions can access their arguments with
1996 the <a href="#int_varargs">variable argument handling intrinsic</a>
Chris Lattner47f2a832010-03-02 06:36:51 +0000[diff] [blame]1997 functions. '<tt>&lt;returntype&gt;</tt>' is any type except
Nick Lewycky93e06a52009-09-27 23:27:42 +0000[diff] [blame]1998 <a href="#t_label">label</a>.</p>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]1999
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2000<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]2001<table class="layout">
2002 <tr class="layout">
Reid Spencer58c08712006-12-31 07:18:34 +0000[diff] [blame]2003 <td class="left"><tt>i32 (i32)</tt></td>
2004 <td class="left">function taking an <tt>i32</tt>, returning an <tt>i32</tt>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]2005 </td>
Reid Spencer58c08712006-12-31 07:18:34 +0000[diff] [blame]2006 </tr><tr class="layout">
Chris Lattner47f2a832010-03-02 06:36:51 +0000[diff] [blame]2007 <td class="left"><tt>float&nbsp;(i16,&nbsp;i32&nbsp;*)&nbsp;*
Reid Spencer655dcc62006-12-31 07:20:23 +0000[diff] [blame]2008 </tt></td>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]2009 <td class="left"><a href="#t_pointer">Pointer</a> to a function that takes
Chris Lattner47f2a832010-03-02 06:36:51 +0000[diff] [blame]2010 an <tt>i16</tt> and a <a href="#t_pointer">pointer</a> to <tt>i32</tt>,
2011 returning <tt>float</tt>.
Reid Spencer58c08712006-12-31 07:18:34 +0000[diff] [blame]2012 </td>
2013 </tr><tr class="layout">
2014 <td class="left"><tt>i32 (i8*, ...)</tt></td>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]2015 <td class="left">A vararg function that takes at least one
2016 <a href="#t_pointer">pointer</a> to <tt>i8 </tt> (char in C),
2017 which returns an integer. This is the signature for <tt>printf</tt> in
Reid Spencer58c08712006-12-31 07:18:34 +0000[diff] [blame]2018 LLVM.
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]2019 </td>
Devang Patele3dfc1c2008-03-24 05:35:41 +0000[diff] [blame]2020 </tr><tr class="layout">
2021 <td class="left"><tt>{i32, i32} (i32)</tt></td>
Nick Lewycky14d1ccc2009-09-27 07:55:32 +0000[diff] [blame]2022 <td class="left">A function taking an <tt>i32</tt>, returning a
2023 <a href="#t_struct">structure</a> containing two <tt>i32</tt> values
Devang Patele3dfc1c2008-03-24 05:35:41 +0000[diff] [blame]2024 </td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]2025 </tr>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2026</table>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]2027
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2028</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2029
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2030<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2031<h4>
2032 <a name="t_struct">Structure Type</a>
2033</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2034
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2035<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2036
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2037<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2038<p>The structure type is used to represent a collection of data members together
Chris Lattnerb1ed91f2011-07-09 17:41:24 +0000[diff] [blame]2039 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]2040
Jeffrey Yasskinf991bbb2010-01-11 19:19:26 +0000[diff] [blame]2041<p>Structures in memory are accessed using '<tt><a href="#i_load">load</a></tt>'
2042 and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a field
2043 with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.
2044 Structures in registers are accessed using the
2045 '<tt><a href="#i_extractvalue">extractvalue</a></tt>' and
2046 '<tt><a href="#i_insertvalue">insertvalue</a></tt>' instructions.</p>
Chris Lattnerb1ed91f2011-07-09 17:41:24 +0000[diff] [blame]2047
2048<p>Structures may optionally be "packed" structures, which indicate that the
2049 alignment of the struct is one byte, and that there is no padding between
Chris Lattner190552d2011-08-12 17:31:02 +0000[diff] [blame]2050 the elements. In non-packed structs, padding between field types is inserted
2051 as defined by the TargetData string in the module, which is required to match
2052 what the underlying processor expects.</p>
Chris Lattnerb1ed91f2011-07-09 17:41:24 +0000[diff] [blame]2053
Chris Lattner190552d2011-08-12 17:31:02 +0000[diff] [blame]2054<p>Structures can either be "literal" or "identified". A literal structure is
2055 defined inline with other types (e.g. <tt>{i32, i32}*</tt>) whereas identified
2056 types are always defined at the top level with a name. Literal types are
2057 uniqued by their contents and can never be recursive or opaque since there is
Chris Lattner32531732011-08-12 18:12:40 +0000[diff] [blame]2058 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]2059 never uniqued.
Chris Lattnerb1ed91f2011-07-09 17:41:24 +0000[diff] [blame]2060</p>
2061
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2062<h5>Syntax:</h5>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]2063<pre>
Chris Lattner190552d2011-08-12 17:31:02 +0000[diff] [blame]2064 %T1 = type { &lt;type list&gt; } <i>; Identified normal struct type</i>
2065 %T2 = type &lt;{ &lt;type list&gt; }&gt; <i>; Identified packed struct type</i>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]2066</pre>
Chris Lattnerb1ed91f2011-07-09 17:41:24 +0000[diff] [blame]2067
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2068<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]2069<table class="layout">
2070 <tr class="layout">
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]2071 <td class="left"><tt>{ i32, i32, i32 }</tt></td>
2072 <td class="left">A triple of three <tt>i32</tt> values</td>
Chris Lattnerb1ed91f2011-07-09 17:41:24 +0000[diff] [blame]2073 </tr>
2074 <tr class="layout">
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]2075 <td class="left"><tt>{&nbsp;float,&nbsp;i32&nbsp;(i32)&nbsp;*&nbsp;}</tt></td>
2076 <td class="left">A pair, where the first element is a <tt>float</tt> and the
2077 second element is a <a href="#t_pointer">pointer</a> to a
2078 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
2079 an <tt>i32</tt>.</td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]2080 </tr>
Chris Lattnerb1ed91f2011-07-09 17:41:24 +0000[diff] [blame]2081 <tr class="layout">
2082 <td class="left"><tt>&lt;{ i8, i32 }&gt;</tt></td>
2083 <td class="left">A packed struct known to be 5 bytes in size.</td>
2084 </tr>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2085</table>
Dan Gohman142ccc02009-01-24 15:58:40 +0000[diff] [blame]2086
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2087</div>
Chris Lattnerb1ed91f2011-07-09 17:41:24 +0000[diff] [blame]2088
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2089<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2090<h4>
Chris Lattner2a843822011-07-23 19:59:08 +0000[diff] [blame]2091 <a name="t_opaque">Opaque Structure Types</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2092</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2093
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2094<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2095
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]2096<h5>Overview:</h5>
Chris Lattner2a843822011-07-23 19:59:08 +0000[diff] [blame]2097<p>Opaque structure types are used to represent named structure types that do
2098 not have a body specified. This corresponds (for example) to the C notion of
2099 a forward declared structure.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2100
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]2101<h5>Syntax:</h5>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]2102<pre>
Chris Lattnerb1ed91f2011-07-09 17:41:24 +0000[diff] [blame]2103 %X = type opaque
2104 %52 = type opaque
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]2105</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2106
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]2107<h5>Examples:</h5>
2108<table class="layout">
2109 <tr class="layout">
Chris Lattnerb1ed91f2011-07-09 17:41:24 +0000[diff] [blame]2110 <td class="left"><tt>opaque</tt></td>
2111 <td class="left">An opaque type.</td>
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]2112 </tr>
2113</table>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2114
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]2115</div>
2116
Chris Lattnerb1ed91f2011-07-09 17:41:24 +0000[diff] [blame]2117
2118
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]2119<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2120<h4>
2121 <a name="t_pointer">Pointer Type</a>
2122</h4>
Chris Lattner4a67c912009-02-08 19:53:29 +0000[diff] [blame]2123
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2124<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2125
2126<h5>Overview:</h5>
Dan Gohman88481112010-02-25 16:50:07 +0000[diff] [blame]2127<p>The pointer type is used to specify memory locations.
2128 Pointers are commonly used to reference objects in memory.</p>
2129
2130<p>Pointer types may have an optional address space attribute defining the
2131 numbered address space where the pointed-to object resides. The default
2132 address space is number zero. The semantics of non-zero address
2133 spaces are target-specific.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2134
2135<p>Note that LLVM does not permit pointers to void (<tt>void*</tt>) nor does it
2136 permit pointers to labels (<tt>label*</tt>). Use <tt>i8*</tt> instead.</p>
Chris Lattner4a67c912009-02-08 19:53:29 +0000[diff] [blame]2137
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]2138<h5>Syntax:</h5>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]2139<pre>
2140 &lt;type&gt; *
2141</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2142
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]2143<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]2144<table class="layout">
2145 <tr class="layout">
Dan Gohman623806e2009-01-04 23:44:43 +0000[diff] [blame]2146 <td class="left"><tt>[4 x i32]*</tt></td>
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]2147 <td class="left">A <a href="#t_pointer">pointer</a> to <a
2148 href="#t_array">array</a> of four <tt>i32</tt> values.</td>
2149 </tr>
2150 <tr class="layout">
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]2151 <td class="left"><tt>i32 (i32*) *</tt></td>
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]2152 <td class="left"> A <a href="#t_pointer">pointer</a> to a <a
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2153 href="#t_function">function</a> that takes an <tt>i32*</tt>, returning an
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]2154 <tt>i32</tt>.</td>
2155 </tr>
2156 <tr class="layout">
2157 <td class="left"><tt>i32 addrspace(5)*</tt></td>
2158 <td class="left">A <a href="#t_pointer">pointer</a> to an <tt>i32</tt> value
2159 that resides in address space #5.</td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]2160 </tr>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2161</table>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2162
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2163</div>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]2164
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]2165<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2166<h4>
2167 <a name="t_vector">Vector Type</a>
2168</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2169
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2170<div>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]2171
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]2172<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2173<p>A vector type is a simple derived type that represents a vector of elements.
2174 Vector types are used when multiple primitive data are operated in parallel
2175 using a single instruction (SIMD). A vector type requires a size (number of
Duncan Sands31c0e0e2009-11-27 13:38:03 +0000[diff] [blame]2176 elements) and an underlying primitive data type. Vector types are considered
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2177 <a href="#t_firstclass">first class</a>.</p>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]2178
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]2179<h5>Syntax:</h5>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]2180<pre>
2181 &lt; &lt;# elements&gt; x &lt;elementtype&gt; &gt;
2182</pre>
2183
Chris Lattnerf11031a2010-10-10 18:20:35 +0000[diff] [blame]2184<p>The number of elements is a constant integer value larger than 0; elementtype
2185 may be any integer or floating point type. Vectors of size zero are not
2186 allowed, and pointers are not allowed as the element type.</p>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]2187
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]2188<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]2189<table class="layout">
2190 <tr class="layout">
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]2191 <td class="left"><tt>&lt;4 x i32&gt;</tt></td>
2192 <td class="left">Vector of 4 32-bit integer values.</td>
2193 </tr>
2194 <tr class="layout">
2195 <td class="left"><tt>&lt;8 x float&gt;</tt></td>
2196 <td class="left">Vector of 8 32-bit floating-point values.</td>
2197 </tr>
2198 <tr class="layout">
2199 <td class="left"><tt>&lt;2 x i64&gt;</tt></td>
2200 <td class="left">Vector of 2 64-bit integer values.</td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]2201 </tr>
2202</table>
Dan Gohman142ccc02009-01-24 15:58:40 +0000[diff] [blame]2203
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2204</div>
2205
Bill Wendlingae8b5ea2011-07-31 06:47:33 +0000[diff] [blame]2206</div>
2207
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2208<!-- *********************************************************************** -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2209<h2><a name="constants">Constants</a></h2>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2210<!-- *********************************************************************** -->
2211
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2212<div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2213
2214<p>LLVM has several different basic types of constants. This section describes
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2215 them all and their syntax.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2216
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2217<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2218<h3>
2219 <a name="simpleconstants">Simple Constants</a>
2220</h3>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2221
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2222<div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2223
2224<dl>
2225 <dt><b>Boolean constants</b></dt>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2226 <dd>The two strings '<tt>true</tt>' and '<tt>false</tt>' are both valid
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]2227 constants of the <tt><a href="#t_integer">i1</a></tt> type.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2228
2229 <dt><b>Integer constants</b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2230 <dd>Standard integers (such as '4') are constants of
2231 the <a href="#t_integer">integer</a> type. Negative numbers may be used
2232 with integer types.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2233
2234 <dt><b>Floating point constants</b></dt>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2235 <dd>Floating point constants use standard decimal notation (e.g. 123.421),
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2236 exponential notation (e.g. 1.23421e+2), or a more precise hexadecimal
2237 notation (see below). The assembler requires the exact decimal value of a
2238 floating-point constant. For example, the assembler accepts 1.25 but
2239 rejects 1.3 because 1.3 is a repeating decimal in binary. Floating point
2240 constants must have a <a href="#t_floating">floating point</a> type. </dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2241
2242 <dt><b>Null pointer constants</b></dt>
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]2243 <dd>The identifier '<tt>null</tt>' is recognized as a null pointer constant
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2244 and must be of <a href="#t_pointer">pointer type</a>.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2245</dl>
2246
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2247<p>The one non-intuitive notation for constants is the hexadecimal form of
2248 floating point constants. For example, the form '<tt>double
2249 0x432ff973cafa8000</tt>' is equivalent to (but harder to read than)
2250 '<tt>double 4.5e+15</tt>'. The only time hexadecimal floating point
2251 constants are required (and the only time that they are generated by the
2252 disassembler) is when a floating point constant must be emitted but it cannot
2253 be represented as a decimal floating point number in a reasonable number of
2254 digits. For example, NaN's, infinities, and other special values are
2255 represented in their IEEE hexadecimal format so that assembly and disassembly
2256 do not cause any bits to change in the constants.</p>
2257
Dale Johannesencd4a3012009-02-11 22:14:51 +0000[diff] [blame]2258<p>When using the hexadecimal form, constants of types float and double are
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2259 represented using the 16-digit form shown above (which matches the IEEE754
2260 representation for double); float values must, however, be exactly
2261 representable as IEE754 single precision. Hexadecimal format is always used
2262 for long double, and there are three forms of long double. The 80-bit format
2263 used by x86 is represented as <tt>0xK</tt> followed by 20 hexadecimal digits.
2264 The 128-bit format used by PowerPC (two adjacent doubles) is represented
2265 by <tt>0xM</tt> followed by 32 hexadecimal digits. The IEEE 128-bit format
2266 is represented by <tt>0xL</tt> followed by 32 hexadecimal digits; no
2267 currently supported target uses this format. Long doubles will only work if
2268 they match the long double format on your target. All hexadecimal formats
2269 are big-endian (sign bit at the left).</p>
2270
Dale Johannesen33e5c352010-10-01 00:48:59 +0000[diff] [blame]2271<p>There are no constants of type x86mmx.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2272</div>
2273
2274<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2275<h3>
Bill Wendling972b7202009-07-20 02:32:41 +0000[diff] [blame]2276<a name="aggregateconstants"></a> <!-- old anchor -->
2277<a name="complexconstants">Complex Constants</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2278</h3>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2279
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2280<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2281
Chris Lattner361bfcd2009-02-28 18:32:25 +0000[diff] [blame]2282<p>Complex constants are a (potentially recursive) combination of simple
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2283 constants and smaller complex constants.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2284
2285<dl>
2286 <dt><b>Structure constants</b></dt>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2287 <dd>Structure constants are represented with notation similar to structure
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2288 type definitions (a comma separated list of elements, surrounded by braces
2289 (<tt>{}</tt>)). For example: "<tt>{ i32 4, float 17.0, i32* @G }</tt>",
2290 where "<tt>@G</tt>" is declared as "<tt>@G = external global i32</tt>".
2291 Structure constants must have <a href="#t_struct">structure type</a>, and
2292 the number and types of elements must match those specified by the
2293 type.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2294
2295 <dt><b>Array constants</b></dt>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2296 <dd>Array constants are represented with notation similar to array type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2297 definitions (a comma separated list of elements, surrounded by square
2298 brackets (<tt>[]</tt>)). For example: "<tt>[ i32 42, i32 11, i32 74
2299 ]</tt>". Array constants must have <a href="#t_array">array type</a>, and
2300 the number and types of elements must match those specified by the
2301 type.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2302
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]2303 <dt><b>Vector constants</b></dt>
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]2304 <dd>Vector constants are represented with notation similar to vector type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2305 definitions (a comma separated list of elements, surrounded by
2306 less-than/greater-than's (<tt>&lt;&gt;</tt>)). For example: "<tt>&lt; i32
2307 42, i32 11, i32 74, i32 100 &gt;</tt>". Vector constants must
2308 have <a href="#t_vector">vector type</a>, and the number and types of
2309 elements must match those specified by the type.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2310
2311 <dt><b>Zero initialization</b></dt>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2312 <dd>The string '<tt>zeroinitializer</tt>' can be used to zero initialize a
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]2313 value to zero of <em>any</em> type, including scalar and
2314 <a href="#t_aggregate">aggregate</a> types.
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2315 This is often used to avoid having to print large zero initializers
2316 (e.g. for large arrays) and is always exactly equivalent to using explicit
2317 zero initializers.</dd>
Nick Lewycky49f89192009-04-04 07:22:01 +0000[diff] [blame]2318
2319 <dt><b>Metadata node</b></dt>
Nick Lewycky8e2c4f42009-05-30 16:08:30 +0000[diff] [blame]2320 <dd>A metadata node is a structure-like constant with
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2321 <a href="#t_metadata">metadata type</a>. For example: "<tt>metadata !{
2322 i32 0, metadata !"test" }</tt>". Unlike other constants that are meant to
2323 be interpreted as part of the instruction stream, metadata is a place to
2324 attach additional information such as debug info.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2325</dl>
2326
2327</div>
2328
2329<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2330<h3>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2331 <a name="globalconstants">Global Variable and Function Addresses</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2332</h3>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2333
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2334<div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2335
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2336<p>The addresses of <a href="#globalvars">global variables</a>
2337 and <a href="#functionstructure">functions</a> are always implicitly valid
2338 (link-time) constants. These constants are explicitly referenced when
2339 the <a href="#identifiers">identifier for the global</a> is used and always
2340 have <a href="#t_pointer">pointer</a> type. For example, the following is a
2341 legal LLVM file:</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2342
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2343<pre class="doc_code">
Chris Lattner00538a12007-06-06 18:28:13 +0000[diff] [blame]2344@X = global i32 17
2345@Y = global i32 42
2346@Z = global [2 x i32*] [ i32* @X, i32* @Y ]
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2347</pre>
2348
2349</div>
2350
2351<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2352<h3>
2353 <a name="undefvalues">Undefined Values</a>
2354</h3>
2355
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2356<div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2357
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2358<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]2359 indicates that the user of the value may receive an unspecified bit-pattern.
Bill Wendling6bbe0912010-10-27 01:07:41 +0000[diff] [blame]2360 Undefined values may be of any type (other than '<tt>label</tt>'
2361 or '<tt>void</tt>') and be used anywhere a constant is permitted.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2362
Chris Lattner92ada5d2009-09-11 01:49:31 +0000[diff] [blame]2363<p>Undefined values are useful because they indicate to the compiler that the
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2364 program is well defined no matter what value is used. This gives the
2365 compiler more freedom to optimize. Here are some examples of (potentially
2366 surprising) transformations that are valid (in pseudo IR):</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2367
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2368
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2369<pre class="doc_code">
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2370 %A = add %X, undef
2371 %B = sub %X, undef
2372 %C = xor %X, undef
2373Safe:
2374 %A = undef
2375 %B = undef
2376 %C = undef
2377</pre>
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2378
2379<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]2380 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]2381
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2382<pre class="doc_code">
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2383 %A = or %X, undef
2384 %B = and %X, undef
2385Safe:
2386 %A = -1
2387 %B = 0
2388Unsafe:
2389 %A = undef
2390 %B = undef
2391</pre>
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2392
2393<p>These logical operations have bits that are not always affected by the input.
Bill Wendling6bbe0912010-10-27 01:07:41 +0000[diff] [blame]2394 For example, if <tt>%X</tt> has a zero bit, then the output of the
2395 '<tt>and</tt>' operation will always be a zero for that bit, no matter what
2396 the corresponding bit from the '<tt>undef</tt>' is. As such, it is unsafe to
2397 optimize or assume that the result of the '<tt>and</tt>' is '<tt>undef</tt>'.
2398 However, it is safe to assume that all bits of the '<tt>undef</tt>' could be
2399 0, and optimize the '<tt>and</tt>' to 0. Likewise, it is safe to assume that
2400 all the bits of the '<tt>undef</tt>' operand to the '<tt>or</tt>' could be
2401 set, allowing the '<tt>or</tt>' to be folded to -1.</p>
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2402
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2403<pre class="doc_code">
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2404 %A = select undef, %X, %Y
2405 %B = select undef, 42, %Y
2406 %C = select %X, %Y, undef
2407Safe:
2408 %A = %X (or %Y)
2409 %B = 42 (or %Y)
2410 %C = %Y
2411Unsafe:
2412 %A = undef
2413 %B = undef
2414 %C = undef
2415</pre>
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2416
Bill Wendling6bbe0912010-10-27 01:07:41 +0000[diff] [blame]2417<p>This set of examples shows that undefined '<tt>select</tt>' (and conditional
2418 branch) conditions can go <em>either way</em>, but they have to come from one
2419 of the two operands. In the <tt>%A</tt> example, if <tt>%X</tt> and
2420 <tt>%Y</tt> were both known to have a clear low bit, then <tt>%A</tt> would
2421 have to have a cleared low bit. However, in the <tt>%C</tt> example, the
2422 optimizer is allowed to assume that the '<tt>undef</tt>' operand could be the
2423 same as <tt>%Y</tt>, allowing the whole '<tt>select</tt>' to be
2424 eliminated.</p>
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2425
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2426<pre class="doc_code">
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2427 %A = xor undef, undef
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]2428
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2429 %B = undef
2430 %C = xor %B, %B
2431
2432 %D = undef
2433 %E = icmp lt %D, 4
2434 %F = icmp gte %D, 4
2435
2436Safe:
2437 %A = undef
2438 %B = undef
2439 %C = undef
2440 %D = undef
2441 %E = undef
2442 %F = undef
2443</pre>
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2444
Bill Wendling6bbe0912010-10-27 01:07:41 +0000[diff] [blame]2445<p>This example points out that two '<tt>undef</tt>' operands are not
2446 necessarily the same. This can be surprising to people (and also matches C
2447 semantics) where they assume that "<tt>X^X</tt>" is always zero, even
2448 if <tt>X</tt> is undefined. This isn't true for a number of reasons, but the
2449 short answer is that an '<tt>undef</tt>' "variable" can arbitrarily change
2450 its value over its "live range". This is true because the variable doesn't
2451 actually <em>have a live range</em>. Instead, the value is logically read
2452 from arbitrary registers that happen to be around when needed, so the value
2453 is not necessarily consistent over time. In fact, <tt>%A</tt> and <tt>%C</tt>
2454 need to have the same semantics or the core LLVM "replace all uses with"
2455 concept would not hold.</p>
Chris Lattnera34a7182009-09-07 23:33:52 +0000[diff] [blame]2456
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2457<pre class="doc_code">
Chris Lattnera34a7182009-09-07 23:33:52 +0000[diff] [blame]2458 %A = fdiv undef, %X
2459 %B = fdiv %X, undef
2460Safe:
2461 %A = undef
2462b: unreachable
2463</pre>
Chris Lattnera34a7182009-09-07 23:33:52 +0000[diff] [blame]2464
2465<p>These examples show the crucial difference between an <em>undefined
Bill Wendling6bbe0912010-10-27 01:07:41 +0000[diff] [blame]2466 value</em> and <em>undefined behavior</em>. An undefined value (like
2467 '<tt>undef</tt>') is allowed to have an arbitrary bit-pattern. This means that
2468 the <tt>%A</tt> operation can be constant folded to '<tt>undef</tt>', because
2469 the '<tt>undef</tt>' could be an SNaN, and <tt>fdiv</tt> is not (currently)
2470 defined on SNaN's. However, in the second example, we can make a more
2471 aggressive assumption: because the <tt>undef</tt> is allowed to be an
2472 arbitrary value, we are allowed to assume that it could be zero. Since a
2473 divide by zero has <em>undefined behavior</em>, we are allowed to assume that
2474 the operation does not execute at all. This allows us to delete the divide and
2475 all code after it. Because the undefined operation "can't happen", the
2476 optimizer can assume that it occurs in dead code.</p>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]2477
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2478<pre class="doc_code">
Chris Lattnera34a7182009-09-07 23:33:52 +0000[diff] [blame]2479a: store undef -> %X
2480b: store %X -> undef
2481Safe:
2482a: &lt;deleted&gt;
2483b: unreachable
2484</pre>
Chris Lattnera34a7182009-09-07 23:33:52 +0000[diff] [blame]2485
Bill Wendling6bbe0912010-10-27 01:07:41 +0000[diff] [blame]2486<p>These examples reiterate the <tt>fdiv</tt> example: a store <em>of</em> an
2487 undefined value can be assumed to not have any effect; we can assume that the
2488 value is overwritten with bits that happen to match what was already there.
2489 However, a store <em>to</em> an undefined location could clobber arbitrary
2490 memory, therefore, it has undefined behavior.</p>
Chris Lattnera34a7182009-09-07 23:33:52 +0000[diff] [blame]2491
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2492</div>
2493
2494<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2495<h3>
2496 <a name="trapvalues">Trap Values</a>
2497</h3>
2498
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2499<div>
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]2500
Dan Gohmanb2a709b2010-04-26 20:21:21 +0000[diff] [blame]2501<p>Trap values are similar to <a href="#undefvalues">undef values</a>, however
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]2502 instead of representing an unspecified bit pattern, they represent the
2503 fact that an instruction or constant expression which cannot evoke side
2504 effects has nevertheless detected a condition which results in undefined
Dan Gohmanb2a709b2010-04-26 20:21:21 +0000[diff] [blame]2505 behavior.</p>
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]2506
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2507<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]2508 only exist when produced by operations such as
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2509 <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]2510
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2511<p>Trap value behavior is defined in terms of value <i>dependence</i>:</p>
Dan Gohmanb8b85c12010-04-26 23:36:52 +0000[diff] [blame]2512
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2513<ul>
2514<li>Values other than <a href="#i_phi"><tt>phi</tt></a> nodes depend on
2515 their operands.</li>
2516
2517<li><a href="#i_phi"><tt>Phi</tt></a> nodes depend on the operand corresponding
2518 to their dynamic predecessor basic block.</li>
2519
2520<li>Function arguments depend on the corresponding actual argument values in
2521 the dynamic callers of their functions.</li>
2522
2523<li><a href="#i_call"><tt>Call</tt></a> instructions depend on the
2524 <a href="#i_ret"><tt>ret</tt></a> instructions that dynamically transfer
2525 control back to them.</li>
2526
Dan Gohman7292a752010-05-03 14:55:22 +0000[diff] [blame]2527<li><a href="#i_invoke"><tt>Invoke</tt></a> instructions depend on the
2528 <a href="#i_ret"><tt>ret</tt></a>, <a href="#i_unwind"><tt>unwind</tt></a>,
2529 or exception-throwing call instructions that dynamically transfer control
2530 back to them.</li>
2531
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2532<li>Non-volatile loads and stores depend on the most recent stores to all of the
2533 referenced memory addresses, following the order in the IR
2534 (including loads and stores implied by intrinsics such as
2535 <a href="#int_memcpy"><tt>@llvm.memcpy</tt></a>.)</li>
2536
Dan Gohman3513ea52010-05-03 14:59:34 +0000[diff] [blame]2537<!-- TODO: In the case of multiple threads, this only applies if the store
2538 "happens-before" the load or store. -->
Dan Gohmanb8b85c12010-04-26 23:36:52 +0000[diff] [blame]2539
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2540<!-- TODO: floating-point exception state -->
Dan Gohmanb8b85c12010-04-26 23:36:52 +0000[diff] [blame]2541
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2542<li>An instruction with externally visible side effects depends on the most
2543 recent preceding instruction with externally visible side effects, following
Dan Gohman6c858db2010-07-06 15:26:33 +0000[diff] [blame]2544 the order in the IR. (This includes
2545 <a href="#volatile">volatile operations</a>.)</li>
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]2546
Dan Gohman7292a752010-05-03 14:55:22 +0000[diff] [blame]2547<li>An instruction <i>control-depends</i> on a
2548 <a href="#terminators">terminator instruction</a>
2549 if the terminator instruction has multiple successors and the instruction
2550 is always executed when control transfers to one of the successors, and
Chris Lattner0ab5e2c2011-04-15 05:18:47 +0000[diff] [blame]2551 may not be executed when control is transferred to another.</li>
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2552
Dan Gohmanc8454ee2011-04-12 23:05:59 +0000[diff] [blame]2553<li>Additionally, an instruction also <i>control-depends</i> on a terminator
2554 instruction if the set of instructions it otherwise depends on would be
Chris Lattner0ab5e2c2011-04-15 05:18:47 +0000[diff] [blame]2555 different if the terminator had transferred control to a different
Dan Gohmanc8454ee2011-04-12 23:05:59 +0000[diff] [blame]2556 successor.</li>
2557
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2558<li>Dependence is transitive.</li>
2559
2560</ul>
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2561
2562<p>Whenever a trap value is generated, all values which depend on it evaluate
2563 to trap. If they have side effects, the evoke their side effects as if each
2564 operand with a trap value were undef. If they have externally-visible side
2565 effects, the behavior is undefined.</p>
2566
2567<p>Here are some examples:</p>
Dan Gohman48a25882010-04-26 20:54:53 +0000[diff] [blame]2568
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2569<pre class="doc_code">
Dan Gohmanb8b85c12010-04-26 23:36:52 +0000[diff] [blame]2570entry:
2571 %trap = sub nuw i32 0, 1 ; Results in a trap value.
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2572 %still_trap = and i32 %trap, 0 ; Whereas (and i32 undef, 0) would return 0.
2573 %trap_yet_again = getelementptr i32* @h, i32 %still_trap
2574 store i32 0, i32* %trap_yet_again ; undefined behavior
2575
2576 store i32 %trap, i32* @g ; Trap value conceptually stored to memory.
2577 %trap2 = load i32* @g ; Returns a trap value, not just undef.
2578
2579 volatile store i32 %trap, i32* @g ; External observation; undefined behavior.
2580
2581 %narrowaddr = bitcast i32* @g to i16*
2582 %wideaddr = bitcast i32* @g to i64*
Nick Lewycky9c876bf2011-05-16 19:29:30 +0000[diff] [blame]2583 %trap3 = load i16* %narrowaddr ; Returns a trap value.
2584 %trap4 = load i64* %wideaddr ; Returns a trap value.
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2585
Nick Lewycky9c876bf2011-05-16 19:29:30 +0000[diff] [blame]2586 %cmp = icmp slt i32 %trap, 0 ; Returns a trap value.
2587 br i1 %cmp, label %true, label %end ; Branch to either destination.
Dan Gohmanb8b85c12010-04-26 23:36:52 +0000[diff] [blame]2588
2589true:
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2590 volatile store i32 0, i32* @g ; This is control-dependent on %cmp, so
2591 ; it has undefined behavior.
Dan Gohmanb8b85c12010-04-26 23:36:52 +0000[diff] [blame]2592 br label %end
2593
2594end:
2595 %p = phi i32 [ 0, %entry ], [ 1, %true ]
2596 ; Both edges into this PHI are
2597 ; control-dependent on %cmp, so this
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2598 ; always results in a trap value.
Dan Gohmanb8b85c12010-04-26 23:36:52 +0000[diff] [blame]2599
Dan Gohmanc8454ee2011-04-12 23:05:59 +0000[diff] [blame]2600 volatile store i32 0, i32* @g ; This would depend on the store in %true
2601 ; if %cmp is true, or the store in %entry
2602 ; otherwise, so this is undefined behavior.
2603
Nick Lewycky9c876bf2011-05-16 19:29:30 +0000[diff] [blame]2604 br i1 %cmp, label %second_true, label %second_end
Dan Gohmanc8454ee2011-04-12 23:05:59 +0000[diff] [blame]2605 ; The same branch again, but this time the
2606 ; true block doesn't have side effects.
2607
2608second_true:
2609 ; No side effects!
Nick Lewycky9c876bf2011-05-16 19:29:30 +0000[diff] [blame]2610 ret void
Dan Gohmanc8454ee2011-04-12 23:05:59 +0000[diff] [blame]2611
2612second_end:
2613 volatile store i32 0, i32* @g ; This time, the instruction always depends
2614 ; on the store in %end. Also, it is
2615 ; control-equivalent to %end, so this is
Nick Lewycky9c876bf2011-05-16 19:29:30 +0000[diff] [blame]2616 ; well-defined (again, ignoring earlier
Dan Gohmanb8b85c12010-04-26 23:36:52 +0000[diff] [blame]2617 ; undefined behavior in this example).
Dan Gohmanb8b85c12010-04-26 23:36:52 +0000[diff] [blame]2618</pre>
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]2619
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]2620</div>
2621
2622<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2623<h3>
2624 <a name="blockaddress">Addresses of Basic Blocks</a>
2625</h3>
2626
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2627<div>
Chris Lattnere4801f72009-10-27 21:01:34 +0000[diff] [blame]2628
Chris Lattneraa99c942009-11-01 01:27:45 +0000[diff] [blame]2629<p><b><tt>blockaddress(@function, %block)</tt></b></p>
Chris Lattnere4801f72009-10-27 21:01:34 +0000[diff] [blame]2630
2631<p>The '<tt>blockaddress</tt>' constant computes the address of the specified
Chris Lattner5c5f0ac2009-10-27 21:49:40 +0000[diff] [blame]2632 basic block in the specified function, and always has an i8* type. Taking
Chris Lattneraa99c942009-11-01 01:27:45 +0000[diff] [blame]2633 the address of the entry block is illegal.</p>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]2634
Chris Lattnere4801f72009-10-27 21:01:34 +0000[diff] [blame]2635<p>This value only has defined behavior when used as an operand to the
Bill Wendling6bbe0912010-10-27 01:07:41 +0000[diff] [blame]2636 '<a href="#i_indirectbr"><tt>indirectbr</tt></a>' instruction, or for
2637 comparisons against null. Pointer equality tests between labels addresses
2638 results in undefined behavior &mdash; though, again, comparison against null
2639 is ok, and no label is equal to the null pointer. This may be passed around
2640 as an opaque pointer sized value as long as the bits are not inspected. This
2641 allows <tt>ptrtoint</tt> and arithmetic to be performed on these values so
2642 long as the original value is reconstituted before the <tt>indirectbr</tt>
2643 instruction.</p>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]2644
Bill Wendling6bbe0912010-10-27 01:07:41 +0000[diff] [blame]2645<p>Finally, some targets may provide defined semantics when using the value as
2646 the operand to an inline assembly, but that is target specific.</p>
Chris Lattnere4801f72009-10-27 21:01:34 +0000[diff] [blame]2647
2648</div>
2649
2650
2651<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2652<h3>
2653 <a name="constantexprs">Constant Expressions</a>
2654</h3>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2655
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2656<div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2657
2658<p>Constant expressions are used to allow expressions involving other constants
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2659 to be used as constants. Constant expressions may be of
2660 any <a href="#t_firstclass">first class</a> type and may involve any LLVM
2661 operation that does not have side effects (e.g. load and call are not
Bill Wendling6bbe0912010-10-27 01:07:41 +0000[diff] [blame]2662 supported). The following is the syntax for constant expressions:</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2663
2664<dl>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2665 <dt><b><tt>trunc (CST to TYPE)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2666 <dd>Truncate a constant to another type. The bit size of CST must be larger
2667 than the bit size of TYPE. Both types must be integers.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2668
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2669 <dt><b><tt>zext (CST to TYPE)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2670 <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]2671 smaller than the bit size of TYPE. Both types must be integers.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2672
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2673 <dt><b><tt>sext (CST to TYPE)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2674 <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]2675 smaller than the bit size of TYPE. Both types must be integers.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2676
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2677 <dt><b><tt>fptrunc (CST to TYPE)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2678 <dd>Truncate a floating point constant to another floating point type. The
2679 size of CST must be larger than the size of TYPE. Both types must be
2680 floating point.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2681
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2682 <dt><b><tt>fpext (CST to TYPE)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2683 <dd>Floating point extend a constant to another type. The size of CST must be
2684 smaller or equal to the size of TYPE. Both types must be floating
2685 point.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2686
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2687 <dt><b><tt>fptoui (CST to TYPE)</tt></b></dt>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2688 <dd>Convert a floating point constant to the corresponding unsigned integer
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2689 constant. TYPE must be a scalar or vector integer type. CST must be of
2690 scalar or vector floating point type. Both CST and TYPE must be scalars,
2691 or vectors of the same number of elements. If the value won't fit in the
2692 integer type, the results are undefined.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2693
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2694 <dt><b><tt>fptosi (CST to TYPE)</tt></b></dt>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2695 <dd>Convert a floating point constant to the corresponding signed integer
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2696 constant. TYPE must be a scalar or vector integer type. CST must be of
2697 scalar or vector floating point type. Both CST and TYPE must be scalars,
2698 or vectors of the same number of elements. If the value won't fit in the
2699 integer type, the results are undefined.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2700
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2701 <dt><b><tt>uitofp (CST to TYPE)</tt></b></dt>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2702 <dd>Convert an unsigned integer constant to the corresponding floating point
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2703 constant. TYPE must be a scalar or vector floating point type. CST must be
2704 of scalar or vector integer type. Both CST and TYPE must be scalars, or
2705 vectors of the same number of elements. If the value won't fit in the
2706 floating point type, the results are undefined.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2707
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2708 <dt><b><tt>sitofp (CST to TYPE)</tt></b></dt>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2709 <dd>Convert a signed integer constant to the corresponding floating point
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2710 constant. TYPE must be a scalar or vector floating point type. CST must be
2711 of scalar or vector integer type. Both CST and TYPE must be scalars, or
2712 vectors of the same number of elements. If the value won't fit in the
2713 floating point type, the results are undefined.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2714
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2715 <dt><b><tt>ptrtoint (CST to TYPE)</tt></b></dt>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]2716 <dd>Convert a pointer typed constant to the corresponding integer constant
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2717 <tt>TYPE</tt> must be an integer type. <tt>CST</tt> must be of pointer
2718 type. The <tt>CST</tt> value is zero extended, truncated, or unchanged to
2719 make it fit in <tt>TYPE</tt>.</dd>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]2720
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2721 <dt><b><tt>inttoptr (CST to TYPE)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2722 <dd>Convert a integer constant to a pointer constant. TYPE must be a pointer
2723 type. CST must be of integer type. The CST value is zero extended,
2724 truncated, or unchanged to make it fit in a pointer size. This one is
2725 <i>really</i> dangerous!</dd>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]2726
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2727 <dt><b><tt>bitcast (CST to TYPE)</tt></b></dt>
Chris Lattner789dee32009-02-28 18:27:03 +0000[diff] [blame]2728 <dd>Convert a constant, CST, to another TYPE. The constraints of the operands
2729 are the same as those for the <a href="#i_bitcast">bitcast
2730 instruction</a>.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2731
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2732 <dt><b><tt>getelementptr (CSTPTR, IDX0, IDX1, ...)</tt></b></dt>
2733 <dt><b><tt>getelementptr inbounds (CSTPTR, IDX0, IDX1, ...)</tt></b></dt>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2734 <dd>Perform the <a href="#i_getelementptr">getelementptr operation</a> on
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2735 constants. As with the <a href="#i_getelementptr">getelementptr</a>
2736 instruction, the index list may have zero or more indexes, which are
2737 required to make sense for the type of "CSTPTR".</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2738
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2739 <dt><b><tt>select (COND, VAL1, VAL2)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2740 <dd>Perform the <a href="#i_select">select operation</a> on constants.</dd>
Reid Spencer9965ee72006-12-04 19:23:19 +0000[diff] [blame]2741
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2742 <dt><b><tt>icmp COND (VAL1, VAL2)</tt></b></dt>
Reid Spencer9965ee72006-12-04 19:23:19 +0000[diff] [blame]2743 <dd>Performs the <a href="#i_icmp">icmp operation</a> on constants.</dd>
2744
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2745 <dt><b><tt>fcmp COND (VAL1, VAL2)</tt></b></dt>
Reid Spencer9965ee72006-12-04 19:23:19 +0000[diff] [blame]2746 <dd>Performs the <a href="#i_fcmp">fcmp operation</a> on constants.</dd>
Robert Bocchino7e97a6d2006-01-10 19:31:34 +0000[diff] [blame]2747
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2748 <dt><b><tt>extractelement (VAL, IDX)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2749 <dd>Perform the <a href="#i_extractelement">extractelement operation</a> on
2750 constants.</dd>
Robert Bocchino7e97a6d2006-01-10 19:31:34 +0000[diff] [blame]2751
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2752 <dt><b><tt>insertelement (VAL, ELT, IDX)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2753 <dd>Perform the <a href="#i_insertelement">insertelement operation</a> on
2754 constants.</dd>
Chris Lattner016a0e52006-04-08 00:13:41 +0000[diff] [blame]2755
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2756 <dt><b><tt>shufflevector (VEC1, VEC2, IDXMASK)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2757 <dd>Perform the <a href="#i_shufflevector">shufflevector operation</a> on
2758 constants.</dd>
Chris Lattner016a0e52006-04-08 00:13:41 +0000[diff] [blame]2759
Nick Lewycky9ab9a7f2010-05-29 06:44:15 +0000[diff] [blame]2760 <dt><b><tt>extractvalue (VAL, IDX0, IDX1, ...)</tt></b></dt>
2761 <dd>Perform the <a href="#i_extractvalue">extractvalue operation</a> on
2762 constants. The index list is interpreted in a similar manner as indices in
2763 a '<a href="#i_getelementptr">getelementptr</a>' operation. At least one
2764 index value must be specified.</dd>
2765
2766 <dt><b><tt>insertvalue (VAL, ELT, IDX0, IDX1, ...)</tt></b></dt>
2767 <dd>Perform the <a href="#i_insertvalue">insertvalue operation</a> on
2768 constants. The index list is interpreted in a similar manner as indices in
2769 a '<a href="#i_getelementptr">getelementptr</a>' operation. At least one
2770 index value must be specified.</dd>
2771
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2772 <dt><b><tt>OPCODE (LHS, RHS)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2773 <dd>Perform the specified operation of the LHS and RHS constants. OPCODE may
2774 be any of the <a href="#binaryops">binary</a>
2775 or <a href="#bitwiseops">bitwise binary</a> operations. The constraints
2776 on operands are the same as those for the corresponding instruction
2777 (e.g. no bitwise operations on floating point values are allowed).</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2778</dl>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2779
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2780</div>
Chris Lattnerb1652612004-03-08 16:49:10 +0000[diff] [blame]2781
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2782</div>
2783
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2784<!-- *********************************************************************** -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2785<h2><a name="othervalues">Other Values</a></h2>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2786<!-- *********************************************************************** -->
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2787<div>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2788<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2789<h3>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2790<a name="inlineasm">Inline Assembler Expressions</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2791</h3>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2792
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2793<div>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2794
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2795<p>LLVM supports inline assembler expressions (as opposed
2796 to <a href="#moduleasm"> Module-Level Inline Assembly</a>) through the use of
2797 a special value. This value represents the inline assembler as a string
2798 (containing the instructions to emit), a list of operand constraints (stored
Dale Johannesen63c94fe2009-10-13 21:56:55 +0000[diff] [blame]2799 as a string), a flag that indicates whether or not the inline asm
Dale Johannesen1cfb9582009-10-21 23:28:00 +0000[diff] [blame]2800 expression has side effects, and a flag indicating whether the function
2801 containing the asm needs to align its stack conservatively. An example
2802 inline assembler expression is:</p>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2803
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2804<pre class="doc_code">
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2805i32 (i32) asm "bswap $0", "=r,r"
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2806</pre>
2807
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2808<p>Inline assembler expressions may <b>only</b> be used as the callee operand of
2809 a <a href="#i_call"><tt>call</tt> instruction</a>. Thus, typically we
2810 have:</p>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2811
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2812<pre class="doc_code">
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2813%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]2814</pre>
2815
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2816<p>Inline asms with side effects not visible in the constraint list must be
2817 marked as having side effects. This is done through the use of the
2818 '<tt>sideeffect</tt>' keyword, like so:</p>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2819
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2820<pre class="doc_code">
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2821call void asm sideeffect "eieio", ""()
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2822</pre>
2823
Dale Johannesen1cfb9582009-10-21 23:28:00 +0000[diff] [blame]2824<p>In some cases inline asms will contain code that will not work unless the
2825 stack is aligned in some way, such as calls or SSE instructions on x86,
2826 yet will not contain code that does that alignment within the asm.
2827 The compiler should make conservative assumptions about what the asm might
2828 contain and should generate its usual stack alignment code in the prologue
2829 if the '<tt>alignstack</tt>' keyword is present:</p>
Dale Johannesen63c94fe2009-10-13 21:56:55 +0000[diff] [blame]2830
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2831<pre class="doc_code">
Dale Johannesen1cfb9582009-10-21 23:28:00 +0000[diff] [blame]2832call void asm alignstack "eieio", ""()
Dale Johannesen63c94fe2009-10-13 21:56:55 +0000[diff] [blame]2833</pre>
Dale Johannesen63c94fe2009-10-13 21:56:55 +0000[diff] [blame]2834
2835<p>If both keywords appear the '<tt>sideeffect</tt>' keyword must come
2836 first.</p>
2837
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2838<p>TODO: The format of the asm and constraints string still need to be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2839 documented here. Constraints on what can be done (e.g. duplication, moving,
2840 etc need to be documented). This is probably best done by reference to
2841 another document that covers inline asm from a holistic perspective.</p>
Chris Lattner51065562010-04-07 05:38:05 +0000[diff] [blame]2842
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2843<h4>
Chris Lattner51065562010-04-07 05:38:05 +0000[diff] [blame]2844<a name="inlineasm_md">Inline Asm Metadata</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2845</h4>
Chris Lattner51065562010-04-07 05:38:05 +0000[diff] [blame]2846
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2847<div>
Chris Lattner51065562010-04-07 05:38:05 +0000[diff] [blame]2848
2849<p>The call instructions that wrap inline asm nodes may have a "!srcloc" MDNode
Chris Lattner79ffdc72010-11-17 08:20:42 +0000[diff] [blame]2850 attached to it that contains a list of constant integers. If present, the
2851 code generator will use the integer as the location cookie value when report
Chris Lattner51065562010-04-07 05:38:05 +0000[diff] [blame]2852 errors through the LLVMContext error reporting mechanisms. This allows a
Dan Gohman61110ae2010-04-28 00:36:01 +0000[diff] [blame]2853 front-end to correlate backend errors that occur with inline asm back to the
Chris Lattner51065562010-04-07 05:38:05 +0000[diff] [blame]2854 source code that produced it. For example:</p>
2855
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2856<pre class="doc_code">
Chris Lattner51065562010-04-07 05:38:05 +0000[diff] [blame]2857call void asm sideeffect "something bad", ""()<b>, !srcloc !42</b>
2858...
2859!42 = !{ i32 1234567 }
2860</pre>
Chris Lattner51065562010-04-07 05:38:05 +0000[diff] [blame]2861
2862<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]2863 IR. If the MDNode contains multiple constants, the code generator will use
2864 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]2865
2866</div>
2867
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2868</div>
2869
Chris Lattnerc2f8f162010-01-15 21:50:19 +0000[diff] [blame]2870<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2871<h3>
2872 <a name="metadata">Metadata Nodes and Metadata Strings</a>
2873</h3>
Chris Lattnerc2f8f162010-01-15 21:50:19 +0000[diff] [blame]2874
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2875<div>
Chris Lattnerc2f8f162010-01-15 21:50:19 +0000[diff] [blame]2876
2877<p>LLVM IR allows metadata to be attached to instructions in the program that
2878 can convey extra information about the code to the optimizers and code
2879 generator. One example application of metadata is source-level debug
2880 information. There are two metadata primitives: strings and nodes. All
2881 metadata has the <tt>metadata</tt> type and is identified in syntax by a
2882 preceding exclamation point ('<tt>!</tt>').</p>
2883
2884<p>A metadata string is a string surrounded by double quotes. It can contain
2885 any character by escaping non-printable characters with "\xx" where "xx" is
2886 the two digit hex code. For example: "<tt>!"test\00"</tt>".</p>
2887
2888<p>Metadata nodes are represented with notation similar to structure constants
2889 (a comma separated list of elements, surrounded by braces and preceded by an
2890 exclamation point). For example: "<tt>!{ metadata !"test\00", i32
2891 10}</tt>". Metadata nodes can have any values as their operand.</p>
2892
2893<p>A <a href="#namedmetadatastructure">named metadata</a> is a collection of
2894 metadata nodes, which can be looked up in the module symbol table. For
2895 example: "<tt>!foo = metadata !{!4, !3}</tt>".
2896
Devang Patel9984bd62010-03-04 23:44:48 +0000[diff] [blame]2897<p>Metadata can be used as function arguments. Here <tt>llvm.dbg.value</tt>
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2898 function is using two metadata arguments.</p>
Devang Patel9984bd62010-03-04 23:44:48 +0000[diff] [blame]2899
Bill Wendlingc0e10672011-03-02 02:17:11 +0000[diff] [blame]2900<div class="doc_code">
2901<pre>
2902call void @llvm.dbg.value(metadata !24, i64 0, metadata !25)
2903</pre>
2904</div>
Devang Patel9984bd62010-03-04 23:44:48 +0000[diff] [blame]2905
2906<p>Metadata can be attached with an instruction. Here metadata <tt>!21</tt> is
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2907 attached with <tt>add</tt> instruction using <tt>!dbg</tt> identifier.</p>
Devang Patel9984bd62010-03-04 23:44:48 +0000[diff] [blame]2908
Bill Wendlingc0e10672011-03-02 02:17:11 +0000[diff] [blame]2909<div class="doc_code">
2910<pre>
2911%indvar.next = add i64 %indvar, 1, !dbg !21
2912</pre>
2913</div>
2914
Chris Lattnerc2f8f162010-01-15 21:50:19 +0000[diff] [blame]2915</div>
2916
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2917</div>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]2918
2919<!-- *********************************************************************** -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2920<h2>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]2921 <a name="intrinsic_globals">Intrinsic Global Variables</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2922</h2>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]2923<!-- *********************************************************************** -->
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2924<div>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]2925<p>LLVM has a number of "magic" global variables that contain data that affect
2926code generation or other IR semantics. These are documented here. All globals
Chris Lattner58f9bb22009-07-20 06:14:25 +0000[diff] [blame]2927of this sort should have a section specified as "<tt>llvm.metadata</tt>". This
2928section and all globals that start with "<tt>llvm.</tt>" are reserved for use
2929by LLVM.</p>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]2930
2931<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2932<h3>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]2933<a name="intg_used">The '<tt>llvm.used</tt>' Global Variable</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2934</h3>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]2935
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2936<div>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]2937
2938<p>The <tt>@llvm.used</tt> global is an array with i8* element type which has <a
2939href="#linkage_appending">appending linkage</a>. This array contains a list of
2940pointers to global variables and functions which may optionally have a pointer
2941cast formed of bitcast or getelementptr. For example, a legal use of it is:</p>
2942
2943<pre>
2944 @X = global i8 4
2945 @Y = global i32 123
2946
2947 @llvm.used = appending global [2 x i8*] [
2948 i8* @X,
2949 i8* bitcast (i32* @Y to i8*)
2950 ], section "llvm.metadata"
2951</pre>
2952
2953<p>If a global variable appears in the <tt>@llvm.used</tt> list, then the
2954compiler, assembler, and linker are required to treat the symbol as if there is
2955a reference to the global that it cannot see. For example, if a variable has
2956internal linkage and no references other than that from the <tt>@llvm.used</tt>
2957list, it cannot be deleted. This is commonly used to represent references from
2958inline asms and other things the compiler cannot "see", and corresponds to
2959"attribute((used))" in GNU C.</p>
2960
2961<p>On some targets, the code generator must emit a directive to the assembler or
2962object file to prevent the assembler and linker from molesting the symbol.</p>
2963
2964</div>
2965
2966<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2967<h3>
2968 <a name="intg_compiler_used">
2969 The '<tt>llvm.compiler.used</tt>' Global Variable
2970 </a>
2971</h3>
Chris Lattner58f9bb22009-07-20 06:14:25 +0000[diff] [blame]2972
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2973<div>
Chris Lattner58f9bb22009-07-20 06:14:25 +0000[diff] [blame]2974
2975<p>The <tt>@llvm.compiler.used</tt> directive is the same as the
2976<tt>@llvm.used</tt> directive, except that it only prevents the compiler from
2977touching the symbol. On targets that support it, this allows an intelligent
2978linker to optimize references to the symbol without being impeded as it would be
2979by <tt>@llvm.used</tt>.</p>
2980
2981<p>This is a rare construct that should only be used in rare circumstances, and
2982should not be exposed to source languages.</p>
2983
2984</div>
2985
2986<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2987<h3>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]2988<a name="intg_global_ctors">The '<tt>llvm.global_ctors</tt>' Global Variable</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2989</h3>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]2990
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2991<div>
David Chisnalla9d4a6f2010-04-30 19:23:49 +0000[diff] [blame]2992<pre>
2993%0 = type { i32, void ()* }
David Chisnallb492b812010-04-30 19:27:35 +0000[diff] [blame]2994@llvm.global_ctors = appending global [1 x %0] [%0 { i32 65535, void ()* @ctor }]
David Chisnalla9d4a6f2010-04-30 19:23:49 +0000[diff] [blame]2995</pre>
2996<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.
2997</p>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]2998
2999</div>
3000
3001<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3002<h3>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]3003<a name="intg_global_dtors">The '<tt>llvm.global_dtors</tt>' Global Variable</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3004</h3>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]3005
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3006<div>
David Chisnalla9d4a6f2010-04-30 19:23:49 +0000[diff] [blame]3007<pre>
3008%0 = type { i32, void ()* }
David Chisnallb492b812010-04-30 19:27:35 +0000[diff] [blame]3009@llvm.global_dtors = appending global [1 x %0] [%0 { i32 65535, void ()* @dtor }]
David Chisnalla9d4a6f2010-04-30 19:23:49 +0000[diff] [blame]3010</pre>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]3011
David Chisnalla9d4a6f2010-04-30 19:23:49 +0000[diff] [blame]3012<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.
3013</p>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]3014
3015</div>
3016
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3017</div>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]3018
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]3019<!-- *********************************************************************** -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3020<h2><a name="instref">Instruction Reference</a></h2>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3021<!-- *********************************************************************** -->
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]3022
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3023<div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]3024
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3025<p>The LLVM instruction set consists of several different classifications of
3026 instructions: <a href="#terminators">terminator
3027 instructions</a>, <a href="#binaryops">binary instructions</a>,
3028 <a href="#bitwiseops">bitwise binary instructions</a>,
3029 <a href="#memoryops">memory instructions</a>, and
3030 <a href="#otherops">other instructions</a>.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]3031
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3032<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3033<h3>
3034 <a name="terminators">Terminator Instructions</a>
3035</h3>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]3036
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3037<div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]3038
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3039<p>As mentioned <a href="#functionstructure">previously</a>, every basic block
3040 in a program ends with a "Terminator" instruction, which indicates which
3041 block should be executed after the current block is finished. These
3042 terminator instructions typically yield a '<tt>void</tt>' value: they produce
3043 control flow, not values (the one exception being the
3044 '<a href="#i_invoke"><tt>invoke</tt></a>' instruction).</p>
3045
Chris Lattnerd3d65ab2011-08-02 20:29:13 +0000[diff] [blame]3046<p>The terminator instructions are:
3047 '<a href="#i_ret"><tt>ret</tt></a>',
3048 '<a href="#i_br"><tt>br</tt></a>',
3049 '<a href="#i_switch"><tt>switch</tt></a>',
3050 '<a href="#i_indirectbr"><tt>indirectbr</tt></a>',
3051 '<a href="#i_invoke"><tt>invoke</tt></a>',
3052 '<a href="#i_unwind"><tt>unwind</tt></a>',
3053 '<a href="#i_resume"><tt>resume</tt></a>', and
3054 '<a href="#i_unreachable"><tt>unreachable</tt></a>'.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]3055
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3056<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3057<h4>
3058 <a name="i_ret">'<tt>ret</tt>' Instruction</a>
3059</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3060
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3061<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3062
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3063<h5>Syntax:</h5>
Dan Gohmancc3132e2008-10-04 19:00:07 +0000[diff] [blame]3064<pre>
3065 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]3066 ret void <i>; Return from void function</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3067</pre>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]3068
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3069<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3070<p>The '<tt>ret</tt>' instruction is used to return control flow (and optionally
3071 a value) from a function back to the caller.</p>
3072
3073<p>There are two forms of the '<tt>ret</tt>' instruction: one that returns a
3074 value and then causes control flow, and one that just causes control flow to
3075 occur.</p>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]3076
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3077<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3078<p>The '<tt>ret</tt>' instruction optionally accepts a single argument, the
3079 return value. The type of the return value must be a
3080 '<a href="#t_firstclass">first class</a>' type.</p>
Dan Gohmancc3132e2008-10-04 19:00:07 +0000[diff] [blame]3081
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3082<p>A function is not <a href="#wellformed">well formed</a> if it it has a
3083 non-void return type and contains a '<tt>ret</tt>' instruction with no return
3084 value or a return value with a type that does not match its type, or if it
3085 has a void return type and contains a '<tt>ret</tt>' instruction with a
3086 return value.</p>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]3087
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3088<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3089<p>When the '<tt>ret</tt>' instruction is executed, control flow returns back to
3090 the calling function's context. If the caller is a
3091 "<a href="#i_call"><tt>call</tt></a>" instruction, execution continues at the
3092 instruction after the call. If the caller was an
3093 "<a href="#i_invoke"><tt>invoke</tt></a>" instruction, execution continues at
3094 the beginning of the "normal" destination block. If the instruction returns
3095 a value, that value shall set the call or invoke instruction's return
3096 value.</p>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]3097
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3098<h5>Example:</h5>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]3099<pre>
3100 ret i32 5 <i>; Return an integer value of 5</i>
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]3101 ret void <i>; Return from a void function</i>
Bill Wendling050ee8f2009-02-28 22:12:54 +0000[diff] [blame]3102 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]3103</pre>
Dan Gohman3065b612009-01-12 23:12:39 +0000[diff] [blame]3104
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3105</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3106<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3107<h4>
3108 <a name="i_br">'<tt>br</tt>' Instruction</a>
3109</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3110
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3111<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3112
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3113<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3114<pre>
Bill Wendling16b86742011-07-26 10:41:15 +0000[diff] [blame]3115 br i1 &lt;cond&gt;, label &lt;iftrue&gt;, label &lt;iffalse&gt;
3116 br label &lt;dest&gt; <i>; Unconditional branch</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3117</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3118
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3119<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3120<p>The '<tt>br</tt>' instruction is used to cause control flow to transfer to a
3121 different basic block in the current function. There are two forms of this
3122 instruction, corresponding to a conditional branch and an unconditional
3123 branch.</p>
3124
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3125<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3126<p>The conditional branch form of the '<tt>br</tt>' instruction takes a single
3127 '<tt>i1</tt>' value and two '<tt>label</tt>' values. The unconditional form
3128 of the '<tt>br</tt>' instruction takes a single '<tt>label</tt>' value as a
3129 target.</p>
3130
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3131<h5>Semantics:</h5>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]3132<p>Upon execution of a conditional '<tt>br</tt>' instruction, the '<tt>i1</tt>'
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3133 argument is evaluated. If the value is <tt>true</tt>, control flows to the
3134 '<tt>iftrue</tt>' <tt>label</tt> argument. If "cond" is <tt>false</tt>,
3135 control flows to the '<tt>iffalse</tt>' <tt>label</tt> argument.</p>
3136
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3137<h5>Example:</h5>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]3138<pre>
3139Test:
3140 %cond = <a href="#i_icmp">icmp</a> eq i32 %a, %b
3141 br i1 %cond, label %IfEqual, label %IfUnequal
3142IfEqual:
3143 <a href="#i_ret">ret</a> i32 1
3144IfUnequal:
3145 <a href="#i_ret">ret</a> i32 0
3146</pre>
3147
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3148</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3149
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3150<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3151<h4>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]3152 <a name="i_switch">'<tt>switch</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3153</h4>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]3154
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3155<div>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]3156
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3157<h5>Syntax:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]3158<pre>
3159 switch &lt;intty&gt; &lt;value&gt;, label &lt;defaultdest&gt; [ &lt;intty&gt; &lt;val&gt;, label &lt;dest&gt; ... ]
3160</pre>
3161
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3162<h5>Overview:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]3163<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]3164 several different places. It is a generalization of the '<tt>br</tt>'
3165 instruction, allowing a branch to occur to one of many possible
3166 destinations.</p>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]3167
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3168<h5>Arguments:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]3169<p>The '<tt>switch</tt>' instruction uses three parameters: an integer
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3170 comparison value '<tt>value</tt>', a default '<tt>label</tt>' destination,
3171 and an array of pairs of comparison value constants and '<tt>label</tt>'s.
3172 The table is not allowed to contain duplicate constant entries.</p>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]3173
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3174<h5>Semantics:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3175<p>The <tt>switch</tt> instruction specifies a table of values and
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3176 destinations. When the '<tt>switch</tt>' instruction is executed, this table
3177 is searched for the given value. If the value is found, control flow is
Benjamin Kramer0f420382009-10-12 14:46:08 +0000[diff] [blame]3178 transferred to the corresponding destination; otherwise, control flow is
3179 transferred to the default destination.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3180
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]3181<h5>Implementation:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]3182<p>Depending on properties of the target machine and the particular
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3183 <tt>switch</tt> instruction, this instruction may be code generated in
3184 different ways. For example, it could be generated as a series of chained
3185 conditional branches or with a lookup table.</p>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]3186
3187<h5>Example:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]3188<pre>
3189 <i>; Emulate a conditional br instruction</i>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]3190 %Val = <a href="#i_zext">zext</a> i1 %value to i32
Dan Gohman623806e2009-01-04 23:44:43 +0000[diff] [blame]3191 switch i32 %Val, label %truedest [ i32 0, label %falsedest ]
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]3192
3193 <i>; Emulate an unconditional br instruction</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3194 switch i32 0, label %dest [ ]
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]3195
3196 <i>; Implement a jump table:</i>
Dan Gohman623806e2009-01-04 23:44:43 +0000[diff] [blame]3197 switch i32 %val, label %otherwise [ i32 0, label %onzero
3198 i32 1, label %onone
3199 i32 2, label %ontwo ]
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3200</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3201
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3202</div>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3203
Chris Lattner3ed871f2009-10-27 19:13:16 +0000[diff] [blame]3204
3205<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3206<h4>
Chris Lattnerd04cb6d2009-10-28 00:19:10 +0000[diff] [blame]3207 <a name="i_indirectbr">'<tt>indirectbr</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3208</h4>
Chris Lattner3ed871f2009-10-27 19:13:16 +0000[diff] [blame]3209
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3210<div>
Chris Lattner3ed871f2009-10-27 19:13:16 +0000[diff] [blame]3211
3212<h5>Syntax:</h5>
3213<pre>
Chris Lattnerd04cb6d2009-10-28 00:19:10 +0000[diff] [blame]3214 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]3215</pre>
3216
3217<h5>Overview:</h5>
3218
Chris Lattnerd04cb6d2009-10-28 00:19:10 +0000[diff] [blame]3219<p>The '<tt>indirectbr</tt>' instruction implements an indirect branch to a label
Chris Lattner3ed871f2009-10-27 19:13:16 +0000[diff] [blame]3220 within the current function, whose address is specified by
Chris Lattnere4801f72009-10-27 21:01:34 +0000[diff] [blame]3221 "<tt>address</tt>". Address must be derived from a <a
3222 href="#blockaddress">blockaddress</a> constant.</p>
Chris Lattner3ed871f2009-10-27 19:13:16 +0000[diff] [blame]3223
3224<h5>Arguments:</h5>
3225
3226<p>The '<tt>address</tt>' argument is the address of the label to jump to. The
3227 rest of the arguments indicate the full set of possible destinations that the
3228 address may point to. Blocks are allowed to occur multiple times in the
3229 destination list, though this isn't particularly useful.</p>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3230
Chris Lattner3ed871f2009-10-27 19:13:16 +0000[diff] [blame]3231<p>This destination list is required so that dataflow analysis has an accurate
3232 understanding of the CFG.</p>
3233
3234<h5>Semantics:</h5>
3235
3236<p>Control transfers to the block specified in the address argument. All
3237 possible destination blocks must be listed in the label list, otherwise this
3238 instruction has undefined behavior. This implies that jumps to labels
3239 defined in other functions have undefined behavior as well.</p>
3240
3241<h5>Implementation:</h5>
3242
3243<p>This is typically implemented with a jump through a register.</p>
3244
3245<h5>Example:</h5>
3246<pre>
Chris Lattnerd04cb6d2009-10-28 00:19:10 +0000[diff] [blame]3247 indirectbr i8* %Addr, [ label %bb1, label %bb2, label %bb3 ]
Chris Lattner3ed871f2009-10-27 19:13:16 +0000[diff] [blame]3248</pre>
3249
3250</div>
3251
3252
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3253<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3254<h4>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3255 <a name="i_invoke">'<tt>invoke</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3256</h4>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3257
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3258<div>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3259
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3260<h5>Syntax:</h5>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3261<pre>
Devang Patel02256232008-10-07 17:48:33 +0000[diff] [blame]3262 &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]3263 to label &lt;normal label&gt; unwind label &lt;exception label&gt;
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3264</pre>
3265
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]3266<h5>Overview:</h5>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3267<p>The '<tt>invoke</tt>' instruction causes control to transfer to a specified
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3268 function, with the possibility of control flow transfer to either the
3269 '<tt>normal</tt>' label or the '<tt>exception</tt>' label. If the callee
3270 function returns with the "<tt><a href="#i_ret">ret</a></tt>" instruction,
3271 control flow will return to the "normal" label. If the callee (or any
3272 indirect callees) returns with the "<a href="#i_unwind"><tt>unwind</tt></a>"
3273 instruction, control is interrupted and continued at the dynamically nearest
3274 "exception" label.</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3275
Bill Wendlingbbcb7cd2011-08-02 21:52:38 +0000[diff] [blame]3276<p>The '<tt>exception</tt>' label is a
3277 <i><a href="ExceptionHandling.html#overview">landing pad</a></i> for the
3278 exception. As such, '<tt>exception</tt>' label is required to have the
3279 "<a href="#i_landingpad"><tt>landingpad</tt></a>" instruction, which contains
3280 the information about about the behavior of the program after unwinding
3281 happens, as its first non-PHI instruction. The restrictions on the
3282 "<tt>landingpad</tt>" instruction's tightly couples it to the
3283 "<tt>invoke</tt>" instruction, so that the important information contained
3284 within the "<tt>landingpad</tt>" instruction can't be lost through normal
3285 code motion.</p>
3286
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3287<h5>Arguments:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3288<p>This instruction requires several arguments:</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3289
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3290<ol>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3291 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
3292 convention</a> the call should use. If none is specified, the call
3293 defaults to using C calling conventions.</li>
Devang Patel7e9b05e2008-10-06 18:50:38 +0000[diff] [blame]3294
3295 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3296 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
3297 '<tt>inreg</tt>' attributes are valid here.</li>
Devang Patel7e9b05e2008-10-06 18:50:38 +0000[diff] [blame]3298
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3299 <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]3300 function value being invoked. In most cases, this is a direct function
3301 invocation, but indirect <tt>invoke</tt>s are just as possible, branching
3302 off an arbitrary pointer to function value.</li>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3303
3304 <li>'<tt>function ptr val</tt>': An LLVM value containing a pointer to a
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3305 function to be invoked. </li>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3306
3307 <li>'<tt>function args</tt>': argument list whose types match the function
Chris Lattner47f2a832010-03-02 06:36:51 +0000[diff] [blame]3308 signature argument types and parameter attributes. All arguments must be
3309 of <a href="#t_firstclass">first class</a> type. If the function
3310 signature indicates the function accepts a variable number of arguments,
3311 the extra arguments can be specified.</li>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3312
3313 <li>'<tt>normal label</tt>': the label reached when the called function
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3314 executes a '<tt><a href="#i_ret">ret</a></tt>' instruction. </li>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3315
3316 <li>'<tt>exception label</tt>': the label reached when a callee returns with
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3317 the <a href="#i_unwind"><tt>unwind</tt></a> instruction. </li>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3318
Devang Patel02256232008-10-07 17:48:33 +0000[diff] [blame]3319 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3320 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
3321 '<tt>readnone</tt>' attributes are valid here.</li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3322</ol>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3323
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3324<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3325<p>This instruction is designed to operate as a standard
3326 '<tt><a href="#i_call">call</a></tt>' instruction in most regards. The
3327 primary difference is that it establishes an association with a label, which
3328 is used by the runtime library to unwind the stack.</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3329
3330<p>This instruction is used in languages with destructors to ensure that proper
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3331 cleanup is performed in the case of either a <tt>longjmp</tt> or a thrown
3332 exception. Additionally, this is important for implementation of
3333 '<tt>catch</tt>' clauses in high-level languages that support them.</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3334
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3335<p>For the purposes of the SSA form, the definition of the value returned by the
3336 '<tt>invoke</tt>' instruction is deemed to occur on the edge from the current
3337 block to the "normal" label. If the callee unwinds then no return value is
3338 available.</p>
Dan Gohman9069d892009-05-22 21:47:08 +0000[diff] [blame]3339
Chris Lattner97257f82010-01-15 18:08:37 +0000[diff] [blame]3340<p>Note that the code generator does not yet completely support unwind, and
3341that the invoke/unwind semantics are likely to change in future versions.</p>
3342
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3343<h5>Example:</h5>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3344<pre>
Nick Lewycky084ab472008-03-16 07:18:12 +0000[diff] [blame]3345 %retval = invoke i32 @Test(i32 15) to label %Continue
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]3346 unwind label %TestCleanup <i>; {i32}:retval set</i>
Nick Lewycky084ab472008-03-16 07:18:12 +0000[diff] [blame]3347 %retval = invoke <a href="#callingconv">coldcc</a> i32 %Testfnptr(i32 15) to label %Continue
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]3348 unwind label %TestCleanup <i>; {i32}:retval set</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3349</pre>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3350
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3351</div>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3352
Chris Lattner5ed60612003-09-03 00:41:47 +0000[diff] [blame]3353<!-- _______________________________________________________________________ -->
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3354
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3355<h4>
3356 <a name="i_unwind">'<tt>unwind</tt>' Instruction</a>
3357</h4>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3358
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3359<div>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3360
Chris Lattner5ed60612003-09-03 00:41:47 +0000[diff] [blame]3361<h5>Syntax:</h5>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3362<pre>
3363 unwind
3364</pre>
3365
Chris Lattner5ed60612003-09-03 00:41:47 +0000[diff] [blame]3366<h5>Overview:</h5>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3367<p>The '<tt>unwind</tt>' instruction unwinds the stack, continuing control flow
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3368 at the first callee in the dynamic call stack which used
3369 an <a href="#i_invoke"><tt>invoke</tt></a> instruction to perform the call.
3370 This is primarily used to implement exception handling.</p>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3371
Chris Lattner5ed60612003-09-03 00:41:47 +0000[diff] [blame]3372<h5>Semantics:</h5>
Chris Lattnerfe8519c2008-04-19 21:01:16 +0000[diff] [blame]3373<p>The '<tt>unwind</tt>' instruction causes execution of the current function to
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3374 immediately halt. The dynamic call stack is then searched for the
3375 first <a href="#i_invoke"><tt>invoke</tt></a> instruction on the call stack.
3376 Once found, execution continues at the "exceptional" destination block
3377 specified by the <tt>invoke</tt> instruction. If there is no <tt>invoke</tt>
3378 instruction in the dynamic call chain, undefined behavior results.</p>
3379
Chris Lattner97257f82010-01-15 18:08:37 +0000[diff] [blame]3380<p>Note that the code generator does not yet completely support unwind, and
3381that the invoke/unwind semantics are likely to change in future versions.</p>
3382
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3383</div>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3384
Bill Wendlingf891bf82011-07-31 06:30:59 +0000[diff] [blame]3385 <!-- _______________________________________________________________________ -->
3386
3387<h4>
3388 <a name="i_resume">'<tt>resume</tt>' Instruction</a>
3389</h4>
3390
3391<div>
3392
3393<h5>Syntax:</h5>
3394<pre>
3395 resume &lt;type&gt; &lt;value&gt;
3396</pre>
3397
3398<h5>Overview:</h5>
3399<p>The '<tt>resume</tt>' instruction is a terminator instruction that has no
3400 successors.</p>
3401
3402<h5>Arguments:</h5>
Bill Wendlingbbcb7cd2011-08-02 21:52:38 +0000[diff] [blame]3403<p>The '<tt>resume</tt>' instruction requires one argument, which must have the
Bill Wendlingc5a13612011-08-03 18:37:32 +0000[diff] [blame]3404 same type as the result of any '<tt>landingpad</tt>' instruction in the same
3405 function.</p>
Bill Wendlingf891bf82011-07-31 06:30:59 +0000[diff] [blame]3406
3407<h5>Semantics:</h5>
3408<p>The '<tt>resume</tt>' instruction resumes propagation of an existing
3409 (in-flight) exception whose unwinding was interrupted with
Bill Wendlingbbcb7cd2011-08-02 21:52:38 +0000[diff] [blame]3410 a <a href="#i_landingpad"><tt>landingpad</tt></a> instruction.</p>
Bill Wendlingf891bf82011-07-31 06:30:59 +0000[diff] [blame]3411
3412<h5>Example:</h5>
3413<pre>
Bill Wendlingbbcb7cd2011-08-02 21:52:38 +0000[diff] [blame]3414 resume { i8*, i32 } %exn
Bill Wendlingf891bf82011-07-31 06:30:59 +0000[diff] [blame]3415</pre>
3416
3417</div>
3418
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3419<!-- _______________________________________________________________________ -->
3420
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3421<h4>
3422 <a name="i_unreachable">'<tt>unreachable</tt>' Instruction</a>
3423</h4>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3424
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3425<div>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3426
3427<h5>Syntax:</h5>
3428<pre>
3429 unreachable
3430</pre>
3431
3432<h5>Overview:</h5>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3433<p>The '<tt>unreachable</tt>' instruction has no defined semantics. This
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3434 instruction is used to inform the optimizer that a particular portion of the
3435 code is not reachable. This can be used to indicate that the code after a
3436 no-return function cannot be reached, and other facts.</p>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3437
3438<h5>Semantics:</h5>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3439<p>The '<tt>unreachable</tt>' instruction has no defined semantics.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3440
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3441</div>
3442
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3443</div>
3444
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3445<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3446<h3>
3447 <a name="binaryops">Binary Operations</a>
3448</h3>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3449
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3450<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3451
3452<p>Binary operators are used to do most of the computation in a program. They
3453 require two operands of the same type, execute an operation on them, and
3454 produce a single value. The operands might represent multiple data, as is
3455 the case with the <a href="#t_vector">vector</a> data type. The result value
3456 has the same type as its operands.</p>
3457
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3458<p>There are several different binary operators:</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3459
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3460<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3461<h4>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3462 <a name="i_add">'<tt>add</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3463</h4>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3464
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3465<div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3466
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3467<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3468<pre>
Dan Gohmanb07de442009-07-20 22:41:19 +0000[diff] [blame]3469 &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]3470 &lt;result&gt; = add nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3471 &lt;result&gt; = add nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3472 &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]3473</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3474
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3475<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3476<p>The '<tt>add</tt>' instruction returns the sum of its two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3477
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3478<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3479<p>The two arguments to the '<tt>add</tt>' instruction must
3480 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3481 integer values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3482
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3483<h5>Semantics:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3484<p>The value produced is the integer sum of the two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3485
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3486<p>If the sum has unsigned overflow, the result returned is the mathematical
3487 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]3488
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3489<p>Because LLVM integers use a two's complement representation, this instruction
3490 is appropriate for both signed and unsigned integers.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3491
Dan Gohman902dfff2009-07-22 22:44:56 +0000[diff] [blame]3492<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3493 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3494 <tt>nsw</tt> keywords are present, the result value of the <tt>add</tt>
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]3495 is a <a href="#trapvalues">trap value</a> if unsigned and/or signed overflow,
3496 respectively, occurs.</p>
Dan Gohmanb07de442009-07-20 22:41:19 +0000[diff] [blame]3497
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3498<h5>Example:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3499<pre>
3500 &lt;result&gt; = add i32 4, %var <i>; yields {i32}:result = 4 + %var</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3501</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3502
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3503</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3504
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3505<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3506<h4>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3507 <a name="i_fadd">'<tt>fadd</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3508</h4>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3509
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3510<div>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3511
3512<h5>Syntax:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3513<pre>
3514 &lt;result&gt; = fadd &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3515</pre>
3516
3517<h5>Overview:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3518<p>The '<tt>fadd</tt>' instruction returns the sum of its two operands.</p>
3519
3520<h5>Arguments:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3521<p>The two arguments to the '<tt>fadd</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3522 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3523 floating point values. Both arguments must have identical types.</p>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3524
3525<h5>Semantics:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3526<p>The value produced is the floating point sum of the two operands.</p>
3527
3528<h5>Example:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3529<pre>
3530 &lt;result&gt; = fadd float 4.0, %var <i>; yields {float}:result = 4.0 + %var</i>
3531</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3532
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3533</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3534
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3535<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3536<h4>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3537 <a name="i_sub">'<tt>sub</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3538</h4>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3539
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3540<div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3541
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3542<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3543<pre>
Dan Gohman902dfff2009-07-22 22:44:56 +0000[diff] [blame]3544 &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]3545 &lt;result&gt; = sub nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3546 &lt;result&gt; = sub nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3547 &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]3548</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3549
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3550<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3551<p>The '<tt>sub</tt>' instruction returns the difference of its two
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3552 operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3553
3554<p>Note that the '<tt>sub</tt>' instruction is used to represent the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3555 '<tt>neg</tt>' instruction present in most other intermediate
3556 representations.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3557
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3558<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3559<p>The two arguments to the '<tt>sub</tt>' instruction must
3560 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3561 integer values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3562
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3563<h5>Semantics:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3564<p>The value produced is the integer difference of the two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3565
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3566<p>If the difference has unsigned overflow, the result returned is the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3567 mathematical result modulo 2<sup>n</sup>, where n is the bit width of the
3568 result.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3569
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3570<p>Because LLVM integers use a two's complement representation, this instruction
3571 is appropriate for both signed and unsigned integers.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3572
Dan Gohman902dfff2009-07-22 22:44:56 +0000[diff] [blame]3573<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3574 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3575 <tt>nsw</tt> keywords are present, the result value of the <tt>sub</tt>
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]3576 is a <a href="#trapvalues">trap value</a> if unsigned and/or signed overflow,
3577 respectively, occurs.</p>
Dan Gohmanb07de442009-07-20 22:41:19 +0000[diff] [blame]3578
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3579<h5>Example:</h5>
Bill Wendling2d8b9a82007-05-29 09:42:13 +0000[diff] [blame]3580<pre>
3581 &lt;result&gt; = sub i32 4, %var <i>; yields {i32}:result = 4 - %var</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3582 &lt;result&gt; = sub i32 0, %val <i>; yields {i32}:result = -%var</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3583</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3584
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3585</div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3586
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3587<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3588<h4>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3589 <a name="i_fsub">'<tt>fsub</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3590</h4>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3591
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3592<div>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3593
3594<h5>Syntax:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3595<pre>
3596 &lt;result&gt; = fsub &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3597</pre>
3598
3599<h5>Overview:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3600<p>The '<tt>fsub</tt>' instruction returns the difference of its two
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3601 operands.</p>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3602
3603<p>Note that the '<tt>fsub</tt>' instruction is used to represent the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3604 '<tt>fneg</tt>' instruction present in most other intermediate
3605 representations.</p>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3606
3607<h5>Arguments:</h5>
Bill Wendling972b7202009-07-20 02:32:41 +0000[diff] [blame]3608<p>The two arguments to the '<tt>fsub</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3609 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3610 floating point values. Both arguments must have identical types.</p>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3611
3612<h5>Semantics:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3613<p>The value produced is the floating point difference of the two operands.</p>
3614
3615<h5>Example:</h5>
3616<pre>
3617 &lt;result&gt; = fsub float 4.0, %var <i>; yields {float}:result = 4.0 - %var</i>
3618 &lt;result&gt; = fsub float -0.0, %val <i>; yields {float}:result = -%var</i>
3619</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3620
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3621</div>
3622
3623<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3624<h4>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3625 <a name="i_mul">'<tt>mul</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3626</h4>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3627
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3628<div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3629
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3630<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3631<pre>
Dan Gohman902dfff2009-07-22 22:44:56 +0000[diff] [blame]3632 &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]3633 &lt;result&gt; = mul nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3634 &lt;result&gt; = mul nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3635 &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]3636</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3637
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3638<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3639<p>The '<tt>mul</tt>' instruction returns the product of its two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3640
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3641<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3642<p>The two arguments to the '<tt>mul</tt>' instruction must
3643 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3644 integer values. Both arguments must have identical types.</p>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3645
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3646<h5>Semantics:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3647<p>The value produced is the integer product of the two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3648
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3649<p>If the result of the multiplication has unsigned overflow, the result
3650 returned is the mathematical result modulo 2<sup>n</sup>, where n is the bit
3651 width of the result.</p>
3652
3653<p>Because LLVM integers use a two's complement representation, and the result
3654 is the same width as the operands, this instruction returns the correct
3655 result for both signed and unsigned integers. If a full product
3656 (e.g. <tt>i32</tt>x<tt>i32</tt>-><tt>i64</tt>) is needed, the operands should
3657 be sign-extended or zero-extended as appropriate to the width of the full
3658 product.</p>
3659
Dan Gohman902dfff2009-07-22 22:44:56 +0000[diff] [blame]3660<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3661 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3662 <tt>nsw</tt> keywords are present, the result value of the <tt>mul</tt>
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]3663 is a <a href="#trapvalues">trap value</a> if unsigned and/or signed overflow,
3664 respectively, occurs.</p>
Dan Gohmanb07de442009-07-20 22:41:19 +0000[diff] [blame]3665
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3666<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3667<pre>
3668 &lt;result&gt; = mul i32 4, %var <i>; yields {i32}:result = 4 * %var</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3669</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3670
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3671</div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3672
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3673<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3674<h4>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3675 <a name="i_fmul">'<tt>fmul</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3676</h4>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3677
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3678<div>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3679
3680<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3681<pre>
3682 &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]3683</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3684
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3685<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3686<p>The '<tt>fmul</tt>' instruction returns the product of its two operands.</p>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3687
3688<h5>Arguments:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3689<p>The two arguments to the '<tt>fmul</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3690 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3691 floating point values. Both arguments must have identical types.</p>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3692
3693<h5>Semantics:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3694<p>The value produced is the floating point product of the two operands.</p>
3695
3696<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3697<pre>
3698 &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]3699</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3700
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3701</div>
3702
3703<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3704<h4>
3705 <a name="i_udiv">'<tt>udiv</tt>' Instruction</a>
3706</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3707
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3708<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3709
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3710<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3711<pre>
Chris Lattner35315d02011-02-06 21:44:57 +0000[diff] [blame]3712 &lt;result&gt; = udiv &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3713 &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]3714</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3715
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3716<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3717<p>The '<tt>udiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3718
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3719<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3720<p>The two arguments to the '<tt>udiv</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3721 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3722 values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3723
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3724<h5>Semantics:</h5>
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3725<p>The value produced is the unsigned integer quotient of the two operands.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3726
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3727<p>Note that unsigned integer division and signed integer division are distinct
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3728 operations; for signed integer division, use '<tt>sdiv</tt>'.</p>
3729
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3730<p>Division by zero leads to undefined behavior.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3731
Chris Lattner35315d02011-02-06 21:44:57 +0000[diff] [blame]3732<p>If the <tt>exact</tt> keyword is present, the result value of the
3733 <tt>udiv</tt> is a <a href="#trapvalues">trap value</a> if %op1 is not a
3734 multiple of %op2 (as such, "((a udiv exact b) mul b) == a").</p>
3735
3736
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3737<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3738<pre>
3739 &lt;result&gt; = udiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3740</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3741
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3742</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3743
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3744<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3745<h4>
3746 <a name="i_sdiv">'<tt>sdiv</tt>' Instruction</a>
3747</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3748
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3749<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3750
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3751<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3752<pre>
Dan Gohmanb07de442009-07-20 22:41:19 +0000[diff] [blame]3753 &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]3754 &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]3755</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3756
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3757<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3758<p>The '<tt>sdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3759
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3760<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3761<p>The two arguments to the '<tt>sdiv</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3762 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3763 values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3764
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3765<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3766<p>The value produced is the signed integer quotient of the two operands rounded
3767 towards zero.</p>
3768
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3769<p>Note that signed integer division and unsigned integer division are distinct
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3770 operations; for unsigned integer division, use '<tt>udiv</tt>'.</p>
3771
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3772<p>Division by zero leads to undefined behavior. Overflow also leads to
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3773 undefined behavior; this is a rare case, but can occur, for example, by doing
3774 a 32-bit division of -2147483648 by -1.</p>
3775
Dan Gohman71dfd782009-07-22 00:04:19 +0000[diff] [blame]3776<p>If the <tt>exact</tt> keyword is present, the result value of the
Dan Gohman57255802010-04-23 15:23:32 +0000[diff] [blame]3777 <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]3778 be rounded.</p>
Dan Gohmanb07de442009-07-20 22:41:19 +0000[diff] [blame]3779
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3780<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3781<pre>
3782 &lt;result&gt; = sdiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3783</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3784
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3785</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3786
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3787<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3788<h4>
3789 <a name="i_fdiv">'<tt>fdiv</tt>' Instruction</a>
3790</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3791
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3792<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3793
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3794<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3795<pre>
Gabor Greif0f75ad02008-08-07 21:46:00 +0000[diff] [blame]3796 &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]3797</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3798
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3799<h5>Overview:</h5>
3800<p>The '<tt>fdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3801
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3802<h5>Arguments:</h5>
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]3803<p>The two arguments to the '<tt>fdiv</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3804 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3805 floating point values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3806
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3807<h5>Semantics:</h5>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3808<p>The value produced is the floating point quotient of the two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3809
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3810<h5>Example:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3811<pre>
3812 &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]3813</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3814
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3815</div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3816
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3817<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3818<h4>
3819 <a name="i_urem">'<tt>urem</tt>' Instruction</a>
3820</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3821
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3822<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3823
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3824<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3825<pre>
3826 &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]3827</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3828
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3829<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3830<p>The '<tt>urem</tt>' instruction returns the remainder from the unsigned
3831 division of its two arguments.</p>
3832
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3833<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3834<p>The two arguments to the '<tt>urem</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3835 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3836 values. Both arguments must have identical types.</p>
3837
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3838<h5>Semantics:</h5>
3839<p>This instruction returns the unsigned integer <i>remainder</i> of a division.
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3840 This instruction always performs an unsigned division to get the
3841 remainder.</p>
3842
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3843<p>Note that unsigned integer remainder and signed integer remainder are
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3844 distinct operations; for signed integer remainder, use '<tt>srem</tt>'.</p>
3845
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3846<p>Taking the remainder of a division by zero leads to undefined behavior.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3847
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3848<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3849<pre>
3850 &lt;result&gt; = urem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3851</pre>
3852
3853</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3854
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3855<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3856<h4>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3857 <a name="i_srem">'<tt>srem</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3858</h4>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3859
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3860<div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3861
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3862<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3863<pre>
Gabor Greif0f75ad02008-08-07 21:46:00 +0000[diff] [blame]3864 &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]3865</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3866
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3867<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3868<p>The '<tt>srem</tt>' instruction returns the remainder from the signed
3869 division of its two operands. This instruction can also take
3870 <a href="#t_vector">vector</a> versions of the values in which case the
3871 elements must be integers.</p>
Chris Lattnerb8f816e2008-01-04 04:33:49 +0000[diff] [blame]3872
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3873<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3874<p>The two arguments to the '<tt>srem</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3875 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3876 values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3877
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3878<h5>Semantics:</h5>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3879<p>This instruction returns the <i>remainder</i> of a division (where the result
Duncan Sands2769c6e2011-03-07 09:12:24 +0000[diff] [blame]3880 is either zero or has the same sign as the dividend, <tt>op1</tt>), not the
3881 <i>modulo</i> operator (where the result is either zero or has the same sign
3882 as the divisor, <tt>op2</tt>) of a value.
3883 For more information about the difference,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3884 see <a href="http://mathforum.org/dr.math/problems/anne.4.28.99.html">The
3885 Math Forum</a>. For a table of how this is implemented in various languages,
3886 please see <a href="http://en.wikipedia.org/wiki/Modulo_operation">
3887 Wikipedia: modulo operation</a>.</p>
3888
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3889<p>Note that signed integer remainder and unsigned integer remainder are
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3890 distinct operations; for unsigned integer remainder, use '<tt>urem</tt>'.</p>
3891
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3892<p>Taking the remainder of a division by zero leads to undefined behavior.
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3893 Overflow also leads to undefined behavior; this is a rare case, but can
3894 occur, for example, by taking the remainder of a 32-bit division of
3895 -2147483648 by -1. (The remainder doesn't actually overflow, but this rule
3896 lets srem be implemented using instructions that return both the result of
3897 the division and the remainder.)</p>
3898
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3899<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3900<pre>
3901 &lt;result&gt; = srem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3902</pre>
3903
3904</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3905
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3906<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3907<h4>
3908 <a name="i_frem">'<tt>frem</tt>' Instruction</a>
3909</h4>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3910
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3911<div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3912
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3913<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3914<pre>
3915 &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]3916</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3917
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3918<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3919<p>The '<tt>frem</tt>' instruction returns the remainder from the division of
3920 its two operands.</p>
3921
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3922<h5>Arguments:</h5>
3923<p>The two arguments to the '<tt>frem</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3924 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3925 floating point values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3926
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3927<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3928<p>This instruction returns the <i>remainder</i> of a division. The remainder
3929 has the same sign as the dividend.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3930
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3931<h5>Example:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3932<pre>
3933 &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]3934</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3935
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3936</div>
Robert Bocchino820bc75b2006-02-17 21:18:08 +0000[diff] [blame]3937
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3938</div>
3939
Reid Spencer2ab01932007-02-02 13:57:07 +0000[diff] [blame]3940<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3941<h3>
3942 <a name="bitwiseops">Bitwise Binary Operations</a>
3943</h3>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3944
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3945<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3946
3947<p>Bitwise binary operators are used to do various forms of bit-twiddling in a
3948 program. They are generally very efficient instructions and can commonly be
3949 strength reduced from other instructions. They require two operands of the
3950 same type, execute an operation on them, and produce a single value. The
3951 resulting value is the same type as its operands.</p>
3952
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3953<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3954<h4>
3955 <a name="i_shl">'<tt>shl</tt>' Instruction</a>
3956</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3957
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3958<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3959
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3960<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3961<pre>
Chris Lattnera676c0f2011-02-07 16:40:21 +0000[diff] [blame]3962 &lt;result&gt; = shl &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3963 &lt;result&gt; = shl nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3964 &lt;result&gt; = shl nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3965 &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]3966</pre>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]3967
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3968<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3969<p>The '<tt>shl</tt>' instruction returns the first operand shifted to the left
3970 a specified number of bits.</p>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]3971
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3972<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3973<p>Both arguments to the '<tt>shl</tt>' instruction must be the
3974 same <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3975 integer type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3976
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3977<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3978<p>The value produced is <tt>op1</tt> * 2<sup><tt>op2</tt></sup> mod
3979 2<sup>n</sup>, where <tt>n</tt> is the width of the result. If <tt>op2</tt>
3980 is (statically or dynamically) negative or equal to or larger than the number
3981 of bits in <tt>op1</tt>, the result is undefined. If the arguments are
3982 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
3983 shift amount in <tt>op2</tt>.</p>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]3984
Chris Lattnera676c0f2011-02-07 16:40:21 +0000[diff] [blame]3985<p>If the <tt>nuw</tt> keyword is present, then the shift produces a
3986 <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]3987 the <tt>nsw</tt> keyword is present, then the shift produces a
Chris Lattnera676c0f2011-02-07 16:40:21 +0000[diff] [blame]3988 <a href="#trapvalues">trap value</a> if it shifts out any bits that disagree
3989 with the resultant sign bit. As such, NUW/NSW have the same semantics as
3990 they would if the shift were expressed as a mul instruction with the same
3991 nsw/nuw bits in (mul %op1, (shl 1, %op2)).</p>
3992
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3993<h5>Example:</h5>
3994<pre>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3995 &lt;result&gt; = shl i32 4, %var <i>; yields {i32}: 4 &lt;&lt; %var</i>
3996 &lt;result&gt; = shl i32 4, 2 <i>; yields {i32}: 16</i>
3997 &lt;result&gt; = shl i32 1, 10 <i>; yields {i32}: 1024</i>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]3998 &lt;result&gt; = shl i32 1, 32 <i>; undefined</i>
Mon P Wang4dd832d2008-12-09 05:46:39 +0000[diff] [blame]3999 &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]4000</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4001
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4002</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4003
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4004<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4005<h4>
4006 <a name="i_lshr">'<tt>lshr</tt>' Instruction</a>
4007</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4008
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4009<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4010
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4011<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4012<pre>
Chris Lattnera676c0f2011-02-07 16:40:21 +0000[diff] [blame]4013 &lt;result&gt; = lshr &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
4014 &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]4015</pre>
4016
4017<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4018<p>The '<tt>lshr</tt>' instruction (logical shift right) returns the first
4019 operand shifted to the right a specified number of bits with zero fill.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4020
4021<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4022<p>Both arguments to the '<tt>lshr</tt>' instruction must be the same
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4023 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
4024 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4025
4026<h5>Semantics:</h5>
4027<p>This instruction always performs a logical shift right operation. The most
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4028 significant bits of the result will be filled with zero bits after the shift.
4029 If <tt>op2</tt> is (statically or dynamically) equal to or larger than the
4030 number of bits in <tt>op1</tt>, the result is undefined. If the arguments are
4031 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
4032 shift amount in <tt>op2</tt>.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4033
Chris Lattnera676c0f2011-02-07 16:40:21 +0000[diff] [blame]4034<p>If the <tt>exact</tt> keyword is present, the result value of the
4035 <tt>lshr</tt> is a <a href="#trapvalues">trap value</a> if any of the bits
4036 shifted out are non-zero.</p>
4037
4038
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4039<h5>Example:</h5>
4040<pre>
4041 &lt;result&gt; = lshr i32 4, 1 <i>; yields {i32}:result = 2</i>
4042 &lt;result&gt; = lshr i32 4, 2 <i>; yields {i32}:result = 1</i>
4043 &lt;result&gt; = lshr i8 4, 3 <i>; yields {i8}:result = 0</i>
4044 &lt;result&gt; = lshr i8 -2, 1 <i>; yields {i8}:result = 0x7FFFFFFF </i>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]4045 &lt;result&gt; = lshr i32 1, 32 <i>; undefined</i>
Mon P Wang4dd832d2008-12-09 05:46:39 +0000[diff] [blame]4046 &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]4047</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4048
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4049</div>
4050
Reid Spencer2ab01932007-02-02 13:57:07 +0000[diff] [blame]4051<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4052<h4>
4053 <a name="i_ashr">'<tt>ashr</tt>' Instruction</a>
4054</h4>
4055
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4056<div>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4057
4058<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4059<pre>
Chris Lattnera676c0f2011-02-07 16:40:21 +0000[diff] [blame]4060 &lt;result&gt; = ashr &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
4061 &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]4062</pre>
4063
4064<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4065<p>The '<tt>ashr</tt>' instruction (arithmetic shift right) returns the first
4066 operand shifted to the right a specified number of bits with sign
4067 extension.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4068
4069<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4070<p>Both arguments to the '<tt>ashr</tt>' instruction must be the same
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4071 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
4072 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4073
4074<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4075<p>This instruction always performs an arithmetic shift right operation, The
4076 most significant bits of the result will be filled with the sign bit
4077 of <tt>op1</tt>. If <tt>op2</tt> is (statically or dynamically) equal to or
4078 larger than the number of bits in <tt>op1</tt>, the result is undefined. If
4079 the arguments are vectors, each vector element of <tt>op1</tt> is shifted by
4080 the corresponding shift amount in <tt>op2</tt>.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4081
Chris Lattnera676c0f2011-02-07 16:40:21 +0000[diff] [blame]4082<p>If the <tt>exact</tt> keyword is present, the result value of the
4083 <tt>ashr</tt> is a <a href="#trapvalues">trap value</a> if any of the bits
4084 shifted out are non-zero.</p>
4085
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4086<h5>Example:</h5>
4087<pre>
4088 &lt;result&gt; = ashr i32 4, 1 <i>; yields {i32}:result = 2</i>
4089 &lt;result&gt; = ashr i32 4, 2 <i>; yields {i32}:result = 1</i>
4090 &lt;result&gt; = ashr i8 4, 3 <i>; yields {i8}:result = 0</i>
4091 &lt;result&gt; = ashr i8 -2, 1 <i>; yields {i8}:result = -1</i>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]4092 &lt;result&gt; = ashr i32 1, 32 <i>; undefined</i>
Mon P Wang4dd832d2008-12-09 05:46:39 +0000[diff] [blame]4093 &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]4094</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4095
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4096</div>
4097
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4098<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4099<h4>
4100 <a name="i_and">'<tt>and</tt>' Instruction</a>
4101</h4>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4102
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4103<div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4104
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4105<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4106<pre>
Gabor Greif0f75ad02008-08-07 21:46:00 +0000[diff] [blame]4107 &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]4108</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4109
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4110<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4111<p>The '<tt>and</tt>' instruction returns the bitwise logical and of its two
4112 operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4113
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4114<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4115<p>The two arguments to the '<tt>and</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4116 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
4117 values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4118
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4119<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4120<p>The truth table used for the '<tt>and</tt>' instruction is:</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4121
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4122<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]4123 <tbody>
4124 <tr>
4125 <td>In0</td>
4126 <td>In1</td>
4127 <td>Out</td>
4128 </tr>
4129 <tr>
4130 <td>0</td>
4131 <td>0</td>
4132 <td>0</td>
4133 </tr>
4134 <tr>
4135 <td>0</td>
4136 <td>1</td>
4137 <td>0</td>
4138 </tr>
4139 <tr>
4140 <td>1</td>
4141 <td>0</td>
4142 <td>0</td>
4143 </tr>
4144 <tr>
4145 <td>1</td>
4146 <td>1</td>
4147 <td>1</td>
4148 </tr>
4149 </tbody>
4150</table>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4151
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4152<h5>Example:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4153<pre>
4154 &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]4155 &lt;result&gt; = and i32 15, 40 <i>; yields {i32}:result = 8</i>
4156 &lt;result&gt; = and i32 4, 8 <i>; yields {i32}:result = 0</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4157</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4158</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4159<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4160<h4>
4161 <a name="i_or">'<tt>or</tt>' Instruction</a>
4162</h4>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4163
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4164<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4165
4166<h5>Syntax:</h5>
4167<pre>
4168 &lt;result&gt; = or &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
4169</pre>
4170
4171<h5>Overview:</h5>
4172<p>The '<tt>or</tt>' instruction returns the bitwise logical inclusive or of its
4173 two operands.</p>
4174
4175<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4176<p>The two arguments to the '<tt>or</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4177 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
4178 values. Both arguments must have identical types.</p>
4179
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4180<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4181<p>The truth table used for the '<tt>or</tt>' instruction is:</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4182
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]4183<table border="1" cellspacing="0" cellpadding="4">
4184 <tbody>
4185 <tr>
4186 <td>In0</td>
4187 <td>In1</td>
4188 <td>Out</td>
4189 </tr>
4190 <tr>
4191 <td>0</td>
4192 <td>0</td>
4193 <td>0</td>
4194 </tr>
4195 <tr>
4196 <td>0</td>
4197 <td>1</td>
4198 <td>1</td>
4199 </tr>
4200 <tr>
4201 <td>1</td>
4202 <td>0</td>
4203 <td>1</td>
4204 </tr>
4205 <tr>
4206 <td>1</td>
4207 <td>1</td>
4208 <td>1</td>
4209 </tr>
4210 </tbody>
4211</table>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4212
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4213<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4214<pre>
4215 &lt;result&gt; = or i32 4, %var <i>; yields {i32}:result = 4 | %var</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4216 &lt;result&gt; = or i32 15, 40 <i>; yields {i32}:result = 47</i>
4217 &lt;result&gt; = or i32 4, 8 <i>; yields {i32}:result = 12</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4218</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4219
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4220</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4221
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4222<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4223<h4>
4224 <a name="i_xor">'<tt>xor</tt>' Instruction</a>
4225</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4226
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4227<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4228
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4229<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4230<pre>
4231 &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]4232</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4233
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4234<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4235<p>The '<tt>xor</tt>' instruction returns the bitwise logical exclusive or of
4236 its two operands. The <tt>xor</tt> is used to implement the "one's
4237 complement" operation, which is the "~" operator in C.</p>
4238
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4239<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4240<p>The two arguments to the '<tt>xor</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4241 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
4242 values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4243
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4244<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4245<p>The truth table used for the '<tt>xor</tt>' instruction is:</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4246
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]4247<table border="1" cellspacing="0" cellpadding="4">
4248 <tbody>
4249 <tr>
4250 <td>In0</td>
4251 <td>In1</td>
4252 <td>Out</td>
4253 </tr>
4254 <tr>
4255 <td>0</td>
4256 <td>0</td>
4257 <td>0</td>
4258 </tr>
4259 <tr>
4260 <td>0</td>
4261 <td>1</td>
4262 <td>1</td>
4263 </tr>
4264 <tr>
4265 <td>1</td>
4266 <td>0</td>
4267 <td>1</td>
4268 </tr>
4269 <tr>
4270 <td>1</td>
4271 <td>1</td>
4272 <td>0</td>
4273 </tr>
4274 </tbody>
4275</table>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4276
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4277<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4278<pre>
4279 &lt;result&gt; = xor i32 4, %var <i>; yields {i32}:result = 4 ^ %var</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4280 &lt;result&gt; = xor i32 15, 40 <i>; yields {i32}:result = 39</i>
4281 &lt;result&gt; = xor i32 4, 8 <i>; yields {i32}:result = 12</i>
4282 &lt;result&gt; = xor i32 %V, -1 <i>; yields {i32}:result = ~%V</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4283</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4284
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4285</div>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4286
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4287</div>
4288
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4289<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4290<h3>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4291 <a name="vectorops">Vector Operations</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4292</h3>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4293
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4294<div>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4295
4296<p>LLVM supports several instructions to represent vector operations in a
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4297 target-independent manner. These instructions cover the element-access and
4298 vector-specific operations needed to process vectors effectively. While LLVM
4299 does directly support these vector operations, many sophisticated algorithms
4300 will want to use target-specific intrinsics to take full advantage of a
4301 specific target.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4302
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4303<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4304<h4>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4305 <a name="i_extractelement">'<tt>extractelement</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4306</h4>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4307
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4308<div>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4309
4310<h5>Syntax:</h5>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4311<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4312 &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]4313</pre>
4314
4315<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4316<p>The '<tt>extractelement</tt>' instruction extracts a single scalar element
4317 from a vector at a specified index.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4318
4319
4320<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4321<p>The first operand of an '<tt>extractelement</tt>' instruction is a value
4322 of <a href="#t_vector">vector</a> type. The second operand is an index
4323 indicating the position from which to extract the element. The index may be
4324 a variable.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4325
4326<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4327<p>The result is a scalar of the same type as the element type of
4328 <tt>val</tt>. Its value is the value at position <tt>idx</tt> of
4329 <tt>val</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
4330 results are undefined.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4331
4332<h5>Example:</h5>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4333<pre>
Gabor Greif03ab4dc2009-10-28 13:14:50 +0000[diff] [blame]4334 &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]4335</pre>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4336
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4337</div>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4338
4339<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4340<h4>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4341 <a name="i_insertelement">'<tt>insertelement</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4342</h4>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4343
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4344<div>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4345
4346<h5>Syntax:</h5>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4347<pre>
Dan Gohman43ba0672008-05-12 23:38:42 +0000[diff] [blame]4348 &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]4349</pre>
4350
4351<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4352<p>The '<tt>insertelement</tt>' instruction inserts a scalar element into a
4353 vector at a specified index.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4354
4355<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4356<p>The first operand of an '<tt>insertelement</tt>' instruction is a value
4357 of <a href="#t_vector">vector</a> type. The second operand is a scalar value
4358 whose type must equal the element type of the first operand. The third
4359 operand is an index indicating the position at which to insert the value.
4360 The index may be a variable.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4361
4362<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4363<p>The result is a vector of the same type as <tt>val</tt>. Its element values
4364 are those of <tt>val</tt> except at position <tt>idx</tt>, where it gets the
4365 value <tt>elt</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
4366 results are undefined.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4367
4368<h5>Example:</h5>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4369<pre>
Gabor Greif03ab4dc2009-10-28 13:14:50 +0000[diff] [blame]4370 &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]4371</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4372
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4373</div>
4374
4375<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4376<h4>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4377 <a name="i_shufflevector">'<tt>shufflevector</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4378</h4>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4379
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4380<div>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4381
4382<h5>Syntax:</h5>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4383<pre>
Mon P Wang25f01062008-11-10 04:46:22 +0000[diff] [blame]4384 &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]4385</pre>
4386
4387<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4388<p>The '<tt>shufflevector</tt>' instruction constructs a permutation of elements
4389 from two input vectors, returning a vector with the same element type as the
4390 input and length that is the same as the shuffle mask.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4391
4392<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4393<p>The first two operands of a '<tt>shufflevector</tt>' instruction are vectors
4394 with types that match each other. The third argument is a shuffle mask whose
4395 element type is always 'i32'. The result of the instruction is a vector
4396 whose length is the same as the shuffle mask and whose element type is the
4397 same as the element type of the first two operands.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4398
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4399<p>The shuffle mask operand is required to be a constant vector with either
4400 constant integer or undef values.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4401
4402<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4403<p>The elements of the two input vectors are numbered from left to right across
4404 both of the vectors. The shuffle mask operand specifies, for each element of
4405 the result vector, which element of the two input vectors the result element
4406 gets. The element selector may be undef (meaning "don't care") and the
4407 second operand may be undef if performing a shuffle from only one vector.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4408
4409<h5>Example:</h5>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4410<pre>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4411 &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]4412 &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]4413 &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]4414 &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]4415 &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]4416 &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]4417 &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]4418 &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]4419</pre>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4420
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4421</div>
Tanya Lattnerb138bbe2006-04-14 19:24:33 +0000[diff] [blame]4422
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4423</div>
4424
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4425<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4426<h3>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4427 <a name="aggregateops">Aggregate Operations</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4428</h3>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4429
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4430<div>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4431
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]4432<p>LLVM supports several instructions for working with
4433 <a href="#t_aggregate">aggregate</a> values.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4434
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4435<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4436<h4>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4437 <a name="i_extractvalue">'<tt>extractvalue</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4438</h4>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4439
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4440<div>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4441
4442<h5>Syntax:</h5>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4443<pre>
4444 &lt;result&gt; = extractvalue &lt;aggregate type&gt; &lt;val&gt;, &lt;idx&gt;{, &lt;idx&gt;}*
4445</pre>
4446
4447<h5>Overview:</h5>
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]4448<p>The '<tt>extractvalue</tt>' instruction extracts the value of a member field
4449 from an <a href="#t_aggregate">aggregate</a> value.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4450
4451<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4452<p>The first operand of an '<tt>extractvalue</tt>' instruction is a value
Chris Lattner13ee7952010-08-28 04:09:24 +0000[diff] [blame]4453 of <a href="#t_struct">struct</a> or
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]4454 <a href="#t_array">array</a> type. The operands are constant indices to
4455 specify which value to extract in a similar manner as indices in a
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4456 '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
Frits van Bommel7cf63ac2010-12-05 20:54:38 +0000[diff] [blame]4457 <p>The major differences to <tt>getelementptr</tt> indexing are:</p>
4458 <ul>
4459 <li>Since the value being indexed is not a pointer, the first index is
4460 omitted and assumed to be zero.</li>
4461 <li>At least one index must be specified.</li>
4462 <li>Not only struct indices but also array indices must be in
4463 bounds.</li>
4464 </ul>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4465
4466<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4467<p>The result is the value at the position in the aggregate specified by the
4468 index operands.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4469
4470<h5>Example:</h5>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4471<pre>
Gabor Greif03ab4dc2009-10-28 13:14:50 +0000[diff] [blame]4472 &lt;result&gt; = extractvalue {i32, float} %agg, 0 <i>; yields i32</i>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4473</pre>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4474
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4475</div>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4476
4477<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4478<h4>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4479 <a name="i_insertvalue">'<tt>insertvalue</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4480</h4>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4481
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4482<div>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4483
4484<h5>Syntax:</h5>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4485<pre>
Bill Wendlingf6a91cf2011-07-26 20:42:28 +0000[diff] [blame]4486 &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]4487</pre>
4488
4489<h5>Overview:</h5>
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]4490<p>The '<tt>insertvalue</tt>' instruction inserts a value into a member field
4491 in an <a href="#t_aggregate">aggregate</a> value.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4492
4493<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4494<p>The first operand of an '<tt>insertvalue</tt>' instruction is a value
Chris Lattner13ee7952010-08-28 04:09:24 +0000[diff] [blame]4495 of <a href="#t_struct">struct</a> or
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]4496 <a href="#t_array">array</a> type. The second operand is a first-class
4497 value to insert. The following operands are constant indices indicating
4498 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]4499 '<tt><a href="#i_extractvalue">extractvalue</a></tt>' instruction. The
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4500 value to insert must have the same type as the value identified by the
4501 indices.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4502
4503<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4504<p>The result is an aggregate of the same type as <tt>val</tt>. Its value is
4505 that of <tt>val</tt> except that the value at the position specified by the
4506 indices is that of <tt>elt</tt>.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4507
4508<h5>Example:</h5>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4509<pre>
Chris Lattnerc2e85402011-05-22 07:18:08 +0000[diff] [blame]4510 %agg1 = insertvalue {i32, float} undef, i32 1, 0 <i>; yields {i32 1, float undef}</i>
4511 %agg2 = insertvalue {i32, float} %agg1, float %val, 1 <i>; yields {i32 1, float %val}</i>
4512 %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]4513</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4514
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4515</div>
4516
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4517</div>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4518
4519<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4520<h3>
Chris Lattner6ab66722006-08-15 00:45:58 +0000[diff] [blame]4521 <a name="memoryops">Memory Access and Addressing Operations</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4522</h3>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4523
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4524<div>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4525
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4526<p>A key design point of an SSA-based representation is how it represents
4527 memory. In LLVM, no memory locations are in SSA form, which makes things
Victor Hernandeza70c6df2009-10-26 23:44:29 +0000[diff] [blame]4528 very simple. This section describes how to read, write, and allocate
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4529 memory in LLVM.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4530
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4531<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4532<h4>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4533 <a name="i_alloca">'<tt>alloca</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4534</h4>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4535
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4536<div>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4537
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4538<h5>Syntax:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4539<pre>
Dan Gohman2140a742010-05-28 01:14:11 +0000[diff] [blame]4540 &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]4541</pre>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4542
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4543<h5>Overview:</h5>
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]4544<p>The '<tt>alloca</tt>' instruction allocates memory on the stack frame of the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4545 currently executing function, to be automatically released when this function
4546 returns to its caller. The object is always allocated in the generic address
4547 space (address space zero).</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4548
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4549<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4550<p>The '<tt>alloca</tt>' instruction
4551 allocates <tt>sizeof(&lt;type&gt;)*NumElements</tt> bytes of memory on the
4552 runtime stack, returning a pointer of the appropriate type to the program.
4553 If "NumElements" is specified, it is the number of elements allocated,
4554 otherwise "NumElements" is defaulted to be one. If a constant alignment is
4555 specified, the value result of the allocation is guaranteed to be aligned to
4556 at least that boundary. If not specified, or if zero, the target can choose
4557 to align the allocation on any convenient boundary compatible with the
4558 type.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4559
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4560<p>'<tt>type</tt>' may be any sized type.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4561
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4562<h5>Semantics:</h5>
Bill Wendling9ee6a312009-05-08 20:49:29 +0000[diff] [blame]4563<p>Memory is allocated; a pointer is returned. The operation is undefined if
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4564 there is insufficient stack space for the allocation. '<tt>alloca</tt>'d
4565 memory is automatically released when the function returns. The
4566 '<tt>alloca</tt>' instruction is commonly used to represent automatic
4567 variables that must have an address available. When the function returns
4568 (either with the <tt><a href="#i_ret">ret</a></tt>
4569 or <tt><a href="#i_unwind">unwind</a></tt> instructions), the memory is
4570 reclaimed. Allocating zero bytes is legal, but the result is undefined.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4571
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4572<h5>Example:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4573<pre>
Dan Gohman7a5acb52009-01-04 23:49:44 +0000[diff] [blame]4574 %ptr = alloca i32 <i>; yields {i32*}:ptr</i>
4575 %ptr = alloca i32, i32 4 <i>; yields {i32*}:ptr</i>
4576 %ptr = alloca i32, i32 4, align 1024 <i>; yields {i32*}:ptr</i>
4577 %ptr = alloca i32, align 1024 <i>; yields {i32*}:ptr</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4578</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4579
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4580</div>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4581
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4582<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4583<h4>
4584 <a name="i_load">'<tt>load</tt>' Instruction</a>
4585</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4586
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4587<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4588
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4589<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4590<pre>
Eli Friedman02e737b2011-08-12 22:50:01 +0000[diff] [blame]4591 &lt;result&gt; = load [volatile] &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;][, !nontemporal !&lt;index&gt;]
4592 &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]4593 !&lt;index&gt; = !{ i32 1 }
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4594</pre>
4595
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4596<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4597<p>The '<tt>load</tt>' instruction is used to read from memory.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4598
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4599<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4600<p>The argument to the '<tt>load</tt>' instruction specifies the memory address
4601 from which to load. The pointer must point to
4602 a <a href="#t_firstclass">first class</a> type. If the <tt>load</tt> is
4603 marked as <tt>volatile</tt>, then the optimizer is not allowed to modify the
Jeffrey Yasskin5d284ae2010-04-26 21:21:24 +0000[diff] [blame]4604 number or order of execution of this <tt>load</tt> with other <a
4605 href="#volatile">volatile operations</a>.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4606
Eli Friedman59b66882011-08-09 23:02:53 +0000[diff] [blame]4607<p>If the <code>load</code> is marked as <code>atomic</code>, it takes an extra
4608 <a href="#ordering">ordering</a> and optional <code>singlethread</code>
4609 argument. The <code>release</code> and <code>acq_rel</code> orderings are
4610 not valid on <code>load</code> instructions. Atomic loads produce <a
4611 href="#memorymodel">defined</a> results when they may see multiple atomic
4612 stores. The type of the pointee must be an integer type whose bit width
4613 is a power of two greater than or equal to eight and less than or equal
4614 to a target-specific size limit. <code>align</code> must be explicitly
4615 specified on atomic loads, and the load has undefined behavior if the
4616 alignment is not set to a value which is at least the size in bytes of
4617 the pointee. <code>!nontemporal</code> does not have any defined semantics
4618 for atomic loads.</p>
4619
Bill Wendlingbc4024f2010-02-25 21:23:24 +0000[diff] [blame]4620<p>The optional constant <tt>align</tt> argument specifies the alignment of the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4621 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]4622 omitted <tt>align</tt> argument means that the operation has the preferential
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4623 alignment for the target. It is the responsibility of the code emitter to
4624 ensure that the alignment information is correct. Overestimating the
Bill Wendlingbc4024f2010-02-25 21:23:24 +0000[diff] [blame]4625 alignment results in undefined behavior. Underestimating the alignment may
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4626 produce less efficient code. An alignment of 1 is always safe.</p>
4627
Bill Wendlingbc4024f2010-02-25 21:23:24 +0000[diff] [blame]4628<p>The optional <tt>!nontemporal</tt> metadata must reference a single
4629 metatadata name &lt;index&gt; corresponding to a metadata node with
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]4630 one <tt>i32</tt> entry of value 1. The existence of
Bill Wendlingbc4024f2010-02-25 21:23:24 +0000[diff] [blame]4631 the <tt>!nontemporal</tt> metatadata on the instruction tells the optimizer
4632 and code generator that this load is not expected to be reused in the cache.
4633 The code generator may select special instructions to save cache bandwidth,
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]4634 such as the <tt>MOVNT</tt> instruction on x86.</p>
David Greene9641d062010-02-16 20:50:18 +0000[diff] [blame]4635
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4636<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4637<p>The location of memory pointed to is loaded. If the value being loaded is of
4638 scalar type then the number of bytes read does not exceed the minimum number
4639 of bytes needed to hold all bits of the type. For example, loading an
4640 <tt>i24</tt> reads at most three bytes. When loading a value of a type like
4641 <tt>i20</tt> with a size that is not an integral number of bytes, the result
4642 is undefined if the value was not originally written using a store of the
4643 same type.</p>
4644
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4645<h5>Examples:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4646<pre>
4647 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
4648 <a href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4649 %val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4650</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4651
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4652</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4653
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4654<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4655<h4>
4656 <a name="i_store">'<tt>store</tt>' Instruction</a>
4657</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4658
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4659<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4660
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4661<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4662<pre>
Eli Friedman02e737b2011-08-12 22:50:01 +0000[diff] [blame]4663 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>
4664 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]4665</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4666
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4667<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4668<p>The '<tt>store</tt>' instruction is used to write to memory.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4669
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4670<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4671<p>There are two arguments to the '<tt>store</tt>' instruction: a value to store
4672 and an address at which to store it. The type of the
4673 '<tt>&lt;pointer&gt;</tt>' operand must be a pointer to
4674 the <a href="#t_firstclass">first class</a> type of the
Jeffrey Yasskin5d284ae2010-04-26 21:21:24 +0000[diff] [blame]4675 '<tt>&lt;value&gt;</tt>' operand. If the <tt>store</tt> is marked as
4676 <tt>volatile</tt>, then the optimizer is not allowed to modify the number or
4677 order of execution of this <tt>store</tt> with other <a
4678 href="#volatile">volatile operations</a>.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4679
Eli Friedman59b66882011-08-09 23:02:53 +0000[diff] [blame]4680<p>If the <code>store</code> is marked as <code>atomic</code>, it takes an extra
4681 <a href="#ordering">ordering</a> and optional <code>singlethread</code>
4682 argument. The <code>acquire</code> and <code>acq_rel</code> orderings aren't
4683 valid on <code>store</code> instructions. Atomic loads produce <a
4684 href="#memorymodel">defined</a> results when they may see multiple atomic
4685 stores. The type of the pointee must be an integer type whose bit width
4686 is a power of two greater than or equal to eight and less than or equal
4687 to a target-specific size limit. <code>align</code> must be explicitly
4688 specified on atomic stores, and the store has undefined behavior if the
4689 alignment is not set to a value which is at least the size in bytes of
4690 the pointee. <code>!nontemporal</code> does not have any defined semantics
4691 for atomic stores.</p>
4692
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4693<p>The optional constant "align" argument specifies the alignment of the
4694 operation (that is, the alignment of the memory address). A value of 0 or an
4695 omitted "align" argument means that the operation has the preferential
4696 alignment for the target. It is the responsibility of the code emitter to
4697 ensure that the alignment information is correct. Overestimating the
4698 alignment results in an undefined behavior. Underestimating the alignment may
4699 produce less efficient code. An alignment of 1 is always safe.</p>
4700
David Greene9641d062010-02-16 20:50:18 +0000[diff] [blame]4701<p>The optional !nontemporal metadata must reference a single metatadata
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]4702 name &lt;index&gt; corresponding to a metadata node with one i32 entry of
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]4703 value 1. The existence of the !nontemporal metatadata on the
David Greene9641d062010-02-16 20:50:18 +0000[diff] [blame]4704 instruction tells the optimizer and code generator that this load is
4705 not expected to be reused in the cache. The code generator may
4706 select special instructions to save cache bandwidth, such as the
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]4707 MOVNT instruction on x86.</p>
David Greene9641d062010-02-16 20:50:18 +0000[diff] [blame]4708
4709
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]4710<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4711<p>The contents of memory are updated to contain '<tt>&lt;value&gt;</tt>' at the
4712 location specified by the '<tt>&lt;pointer&gt;</tt>' operand. If
4713 '<tt>&lt;value&gt;</tt>' is of scalar type then the number of bytes written
4714 does not exceed the minimum number of bytes needed to hold all bits of the
4715 type. For example, storing an <tt>i24</tt> writes at most three bytes. When
4716 writing a value of a type like <tt>i20</tt> with a size that is not an
4717 integral number of bytes, it is unspecified what happens to the extra bits
4718 that do not belong to the type, but they will typically be overwritten.</p>
4719
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4720<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4721<pre>
4722 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Bill Wendling8830ffe2007-10-22 05:10:05 +0000[diff] [blame]4723 store i32 3, i32* %ptr <i>; yields {void}</i>
4724 %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]4725</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4726
Reid Spencer443460a2006-11-09 21:15:49 +0000[diff] [blame]4727</div>
4728
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4729<!-- _______________________________________________________________________ -->
NAKAMURA Takumi0300d882011-08-12 06:17:17 +0000[diff] [blame]4730<h4>
4731<a name="i_fence">'<tt>fence</tt>' Instruction</a>
4732</h4>
Eli Friedmanfee02c62011-07-25 23:16:38 +0000[diff] [blame]4733
NAKAMURA Takumi0300d882011-08-12 06:17:17 +0000[diff] [blame]4734<div>
Eli Friedmanfee02c62011-07-25 23:16:38 +0000[diff] [blame]4735
4736<h5>Syntax:</h5>
4737<pre>
4738 fence [singlethread] &lt;ordering&gt; <i>; yields {void}</i>
4739</pre>
4740
4741<h5>Overview:</h5>
4742<p>The '<tt>fence</tt>' instruction is used to introduce happens-before edges
4743between operations.</p>
4744
4745<h5>Arguments:</h5> <p>'<code>fence</code>' instructions take an <a
4746href="#ordering">ordering</a> argument which defines what
4747<i>synchronizes-with</i> edges they add. They can only be given
4748<code>acquire</code>, <code>release</code>, <code>acq_rel</code>, and
4749<code>seq_cst</code> orderings.</p>
4750
4751<h5>Semantics:</h5>
4752<p>A fence <var>A</var> which has (at least) <code>release</code> ordering
4753semantics <i>synchronizes with</i> a fence <var>B</var> with (at least)
4754<code>acquire</code> ordering semantics if and only if there exist atomic
4755operations <var>X</var> and <var>Y</var>, both operating on some atomic object
4756<var>M</var>, such that <var>A</var> is sequenced before <var>X</var>,
4757<var>X</var> modifies <var>M</var> (either directly or through some side effect
4758of a sequence headed by <var>X</var>), <var>Y</var> is sequenced before
4759<var>B</var>, and <var>Y</var> observes <var>M</var>. This provides a
4760<i>happens-before</i> dependency between <var>A</var> and <var>B</var>. Rather
4761than an explicit <code>fence</code>, one (but not both) of the atomic operations
4762<var>X</var> or <var>Y</var> might provide a <code>release</code> or
4763<code>acquire</code> (resp.) ordering constraint and still
4764<i>synchronize-with</i> the explicit <code>fence</code> and establish the
4765<i>happens-before</i> edge.</p>
4766
4767<p>A <code>fence</code> which has <code>seq_cst</code> ordering, in addition to
4768having both <code>acquire</code> and <code>release</code> semantics specified
4769above, participates in the global program order of other <code>seq_cst</code>
4770operations and/or fences.</p>
4771
4772<p>The optional "<a href="#singlethread"><code>singlethread</code></a>" argument
4773specifies that the fence only synchronizes with other fences in the same
4774thread. (This is useful for interacting with signal handlers.)</p>
4775
Eli Friedmanfee02c62011-07-25 23:16:38 +0000[diff] [blame]4776<h5>Example:</h5>
4777<pre>
4778 fence acquire <i>; yields {void}</i>
4779 fence singlethread seq_cst <i>; yields {void}</i>
4780</pre>
4781
4782</div>
4783
4784<!-- _______________________________________________________________________ -->
NAKAMURA Takumi0300d882011-08-12 06:17:17 +0000[diff] [blame]4785<h4>
4786<a name="i_cmpxchg">'<tt>cmpxchg</tt>' Instruction</a>
4787</h4>
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]4788
NAKAMURA Takumi0300d882011-08-12 06:17:17 +0000[diff] [blame]4789<div>
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]4790
4791<h5>Syntax:</h5>
4792<pre>
Eli Friedman02e737b2011-08-12 22:50:01 +0000[diff] [blame]4793 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]4794</pre>
4795
4796<h5>Overview:</h5>
4797<p>The '<tt>cmpxchg</tt>' instruction is used to atomically modify memory.
4798It loads a value in memory and compares it to a given value. If they are
4799equal, it stores a new value into the memory.</p>
4800
4801<h5>Arguments:</h5>
4802<p>There are three arguments to the '<code>cmpxchg</code>' instruction: an
4803address to operate on, a value to compare to the value currently be at that
4804address, and a new value to place at that address if the compared values are
4805equal. The type of '<var>&lt;cmp&gt;</var>' must be an integer type whose
4806bit width is a power of two greater than or equal to eight and less than
4807or equal to a target-specific size limit. '<var>&lt;cmp&gt;</var>' and
4808'<var>&lt;new&gt;</var>' must have the same type, and the type of
4809'<var>&lt;pointer&gt;</var>' must be a pointer to that type. If the
4810<code>cmpxchg</code> is marked as <code>volatile</code>, then the
4811optimizer is not allowed to modify the number or order of execution
4812of this <code>cmpxchg</code> with other <a href="#volatile">volatile
4813operations</a>.</p>
4814
4815<!-- FIXME: Extend allowed types. -->
4816
4817<p>The <a href="#ordering"><var>ordering</var></a> argument specifies how this
4818<code>cmpxchg</code> synchronizes with other atomic operations.</p>
4819
4820<p>The optional "<code>singlethread</code>" argument declares that the
4821<code>cmpxchg</code> is only atomic with respect to code (usually signal
4822handlers) running in the same thread as the <code>cmpxchg</code>. Otherwise the
4823cmpxchg is atomic with respect to all other code in the system.</p>
4824
4825<p>The pointer passed into cmpxchg must have alignment greater than or equal to
4826the size in memory of the operand.
4827
4828<h5>Semantics:</h5>
4829<p>The contents of memory at the location specified by the
4830'<tt>&lt;pointer&gt;</tt>' operand is read and compared to
4831'<tt>&lt;cmp&gt;</tt>'; if the read value is the equal,
4832'<tt>&lt;new&gt;</tt>' is written. The original value at the location
4833is returned.
4834
4835<p>A successful <code>cmpxchg</code> is a read-modify-write instruction for the
4836purpose of identifying <a href="#release_sequence">release sequences</a>. A
4837failed <code>cmpxchg</code> is equivalent to an atomic load with an ordering
4838parameter determined by dropping any <code>release</code> part of the
4839<code>cmpxchg</code>'s ordering.</p>
4840
4841<!--
4842FIXME: Is compare_exchange_weak() necessary? (Consider after we've done
4843optimization work on ARM.)
4844
4845FIXME: Is a weaker ordering constraint on failure helpful in practice?
4846-->
4847
4848<h5>Example:</h5>
4849<pre>
4850entry:
4851 %orig = atomic <a href="#i_load">load</a> i32* %ptr unordered <i>; yields {i32}</i>
4852 <a href="#i_br">br</a> label %loop
4853
4854loop:
4855 %cmp = <a href="#i_phi">phi</a> i32 [ %orig, %entry ], [%old, %loop]
4856 %squared = <a href="#i_mul">mul</a> i32 %cmp, %cmp
4857 %old = cmpxchg i32* %ptr, i32 %cmp, i32 %squared <i>; yields {i32}</i>
4858 %success = <a href="#i_icmp">icmp</a> eq i32 %cmp, %old
4859 <a href="#i_br">br</a> i1 %success, label %done, label %loop
4860
4861done:
4862 ...
4863</pre>
4864
4865</div>
4866
4867<!-- _______________________________________________________________________ -->
NAKAMURA Takumi0300d882011-08-12 06:17:17 +0000[diff] [blame]4868<h4>
4869<a name="i_atomicrmw">'<tt>atomicrmw</tt>' Instruction</a>
4870</h4>
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]4871
NAKAMURA Takumi0300d882011-08-12 06:17:17 +0000[diff] [blame]4872<div>
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]4873
4874<h5>Syntax:</h5>
4875<pre>
Eli Friedman02e737b2011-08-12 22:50:01 +0000[diff] [blame]4876 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]4877</pre>
4878
4879<h5>Overview:</h5>
4880<p>The '<tt>atomicrmw</tt>' instruction is used to atomically modify memory.</p>
4881
4882<h5>Arguments:</h5>
4883<p>There are three arguments to the '<code>atomicrmw</code>' instruction: an
4884operation to apply, an address whose value to modify, an argument to the
4885operation. The operation must be one of the following keywords:</p>
4886<ul>
4887 <li>xchg</li>
4888 <li>add</li>
4889 <li>sub</li>
4890 <li>and</li>
4891 <li>nand</li>
4892 <li>or</li>
4893 <li>xor</li>
4894 <li>max</li>
4895 <li>min</li>
4896 <li>umax</li>
4897 <li>umin</li>
4898</ul>
4899
4900<p>The type of '<var>&lt;value&gt;</var>' must be an integer type whose
4901bit width is a power of two greater than or equal to eight and less than
4902or equal to a target-specific size limit. The type of the
4903'<code>&lt;pointer&gt;</code>' operand must be a pointer to that type.
4904If the <code>atomicrmw</code> is marked as <code>volatile</code>, then the
4905optimizer is not allowed to modify the number or order of execution of this
4906<code>atomicrmw</code> with other <a href="#volatile">volatile
4907 operations</a>.</p>
4908
4909<!-- FIXME: Extend allowed types. -->
4910
4911<h5>Semantics:</h5>
4912<p>The contents of memory at the location specified by the
4913'<tt>&lt;pointer&gt;</tt>' operand are atomically read, modified, and written
4914back. The original value at the location is returned. The modification is
4915specified by the <var>operation</var> argument:</p>
4916
4917<ul>
4918 <li>xchg: <code>*ptr = val</code></li>
4919 <li>add: <code>*ptr = *ptr + val</code></li>
4920 <li>sub: <code>*ptr = *ptr - val</code></li>
4921 <li>and: <code>*ptr = *ptr &amp; val</code></li>
4922 <li>nand: <code>*ptr = ~(*ptr &amp; val)</code></li>
4923 <li>or: <code>*ptr = *ptr | val</code></li>
4924 <li>xor: <code>*ptr = *ptr ^ val</code></li>
4925 <li>max: <code>*ptr = *ptr &gt; val ? *ptr : val</code> (using a signed comparison)</li>
4926 <li>min: <code>*ptr = *ptr &lt; val ? *ptr : val</code> (using a signed comparison)</li>
4927 <li>umax: <code>*ptr = *ptr &gt; val ? *ptr : val</code> (using an unsigned comparison)</li>
4928 <li>umin: <code>*ptr = *ptr &lt; val ? *ptr : val</code> (using an unsigned comparison)</li>
4929</ul>
4930
4931<h5>Example:</h5>
4932<pre>
4933 %old = atomicrmw add i32* %ptr, i32 1 acquire <i>; yields {i32}</i>
4934</pre>
4935
4936</div>
4937
4938<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4939<h4>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4940 <a name="i_getelementptr">'<tt>getelementptr</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4941</h4>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4942
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4943<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4944
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]4945<h5>Syntax:</h5>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4946<pre>
Matthijs Kooijman0e268272008-10-13 13:44:15 +0000[diff] [blame]4947 &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]4948 &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]4949</pre>
4950
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]4951<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4952<p>The '<tt>getelementptr</tt>' instruction is used to get the address of a
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]4953 subelement of an <a href="#t_aggregate">aggregate</a> data structure.
4954 It performs address calculation only and does not access memory.</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4955
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]4956<h5>Arguments:</h5>
Matthijs Kooijman0e268272008-10-13 13:44:15 +0000[diff] [blame]4957<p>The first argument is always a pointer, and forms the basis of the
Chris Lattnera40b9122009-07-29 06:44:13 +0000[diff] [blame]4958 calculation. The remaining arguments are indices that indicate which of the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4959 elements of the aggregate object are indexed. The interpretation of each
4960 index is dependent on the type being indexed into. The first index always
4961 indexes the pointer value given as the first argument, the second index
4962 indexes a value of the type pointed to (not necessarily the value directly
4963 pointed to, since the first index can be non-zero), etc. The first type
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]4964 indexed into must be a pointer value, subsequent types can be arrays,
Chris Lattner13ee7952010-08-28 04:09:24 +0000[diff] [blame]4965 vectors, and structs. Note that subsequent types being indexed into
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]4966 can never be pointers, since that would require loading the pointer before
4967 continuing calculation.</p>
Matthijs Kooijman0e268272008-10-13 13:44:15 +0000[diff] [blame]4968
4969<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]4970 When indexing into a (optionally packed) structure, only <tt>i32</tt>
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]4971 integer <b>constants</b> are allowed. When indexing into an array, pointer
4972 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]4973 constant. These integers are treated as signed values where relevant.</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4974
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4975<p>For example, let's consider a C code fragment and how it gets compiled to
4976 LLVM:</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4977
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]4978<pre class="doc_code">
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]4979struct RT {
4980 char A;
Chris Lattnera446f1b2007-05-29 15:43:56 +0000[diff] [blame]4981 int B[10][20];
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]4982 char C;
4983};
4984struct ST {
Chris Lattnera446f1b2007-05-29 15:43:56 +0000[diff] [blame]4985 int X;
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]4986 double Y;
4987 struct RT Z;
4988};
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4989
Chris Lattnera446f1b2007-05-29 15:43:56 +0000[diff] [blame]4990int *foo(struct ST *s) {
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]4991 return &amp;s[1].Z.B[5][13];
4992}
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4993</pre>
4994
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4995<p>The LLVM code generated by the GCC frontend is:</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4996
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]4997<pre class="doc_code">
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]4998%RT = <a href="#namedtypes">type</a> { i8 , [10 x [20 x i32]], i8 }
4999%ST = <a href="#namedtypes">type</a> { i32, double, %RT }
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]5000
Dan Gohman6b867702009-07-25 02:23:48 +0000[diff] [blame]5001define i32* @foo(%ST* %s) {
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]5002entry:
5003 %reg = getelementptr %ST* %s, i32 1, i32 2, i32 1, i32 5, i32 13
5004 ret i32* %reg
5005}
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]5006</pre>
5007
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]5008<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5009<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]5010 type, which is a pointer, yielding a '<tt>%ST</tt>' = '<tt>{ i32, double, %RT
5011 }</tt>' type, a structure. The second index indexes into the third element
5012 of the structure, yielding a '<tt>%RT</tt>' = '<tt>{ i8 , [10 x [20 x i32]],
5013 i8 }</tt>' type, another structure. The third index indexes into the second
5014 element of the structure, yielding a '<tt>[10 x [20 x i32]]</tt>' type, an
5015 array. The two dimensions of the array are subscripted into, yielding an
5016 '<tt>i32</tt>' type. The '<tt>getelementptr</tt>' instruction returns a
5017 pointer to this element, thus computing a value of '<tt>i32*</tt>' type.</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]5018
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5019<p>Note that it is perfectly legal to index partially through a structure,
5020 returning a pointer to an inner element. Because of this, the LLVM code for
5021 the given testcase is equivalent to:</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]5022
5023<pre>
Dan Gohman6b867702009-07-25 02:23:48 +0000[diff] [blame]5024 define i32* @foo(%ST* %s) {
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]5025 %t1 = getelementptr %ST* %s, i32 1 <i>; yields %ST*:%t1</i>
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]5026 %t2 = getelementptr %ST* %t1, i32 0, i32 2 <i>; yields %RT*:%t2</i>
5027 %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]5028 %t4 = getelementptr [10 x [20 x i32]]* %t3, i32 0, i32 5 <i>; yields [20 x i32]*:%t4</i>
5029 %t5 = getelementptr [20 x i32]* %t4, i32 0, i32 13 <i>; yields i32*:%t5</i>
5030 ret i32* %t5
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]5031 }
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]5032</pre>
Chris Lattnerc0ad71e2005-06-24 17:22:57 +0000[diff] [blame]5033
Dan Gohman1639c392009-07-27 21:53:46 +0000[diff] [blame]5034<p>If the <tt>inbounds</tt> keyword is present, the result value of the
Dan Gohman57255802010-04-23 15:23:32 +0000[diff] [blame]5035 <tt>getelementptr</tt> is a <a href="#trapvalues">trap value</a> if the
5036 base pointer is not an <i>in bounds</i> address of an allocated object,
5037 or if any of the addresses that would be formed by successive addition of
5038 the offsets implied by the indices to the base address with infinitely
Eli Friedmand8874dc2011-08-12 23:37:55 +0000[diff] [blame]5039 precise signed arithmetic are not an <i>in bounds</i> address of that
5040 allocated object. The <i>in bounds</i> addresses for an allocated object
5041 are all the addresses that point into the object, plus the address one
5042 byte past the end.</p>
Dan Gohman1639c392009-07-27 21:53:46 +0000[diff] [blame]5043
5044<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]5045 the base address with silently-wrapping two's complement arithmetic. If the
5046 offsets have a different width from the pointer, they are sign-extended or
5047 truncated to the width of the pointer. The result value of the
5048 <tt>getelementptr</tt> may be outside the object pointed to by the base
5049 pointer. The result value may not necessarily be used to access memory
5050 though, even if it happens to point into allocated storage. See the
5051 <a href="#pointeraliasing">Pointer Aliasing Rules</a> section for more
5052 information.</p>
Dan Gohman1639c392009-07-27 21:53:46 +0000[diff] [blame]5053
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5054<p>The getelementptr instruction is often confusing. For some more insight into
5055 how it works, see <a href="GetElementPtr.html">the getelementptr FAQ</a>.</p>
Chris Lattner6ab66722006-08-15 00:45:58 +0000[diff] [blame]5056
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]5057<h5>Example:</h5>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]5058<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]5059 <i>; yields [12 x i8]*:aptr</i>
Matthijs Kooijman0e268272008-10-13 13:44:15 +0000[diff] [blame]5060 %aptr = getelementptr {i32, [12 x i8]}* %saptr, i64 0, i32 1
5061 <i>; yields i8*:vptr</i>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]5062 %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]5063 <i>; yields i8*:eptr</i>
5064 %eptr = getelementptr [12 x i8]* %aptr, i64 0, i32 1
Sanjiv Gupta0c155e62009-04-25 07:27:44 +0000[diff] [blame]5065 <i>; yields i32*:iptr</i>
Sanjiv Gupta77abea02009-04-24 16:38:13 +0000[diff] [blame]5066 %iptr = getelementptr [10 x i32]* @arr, i16 0, i16 0
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]5067</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5068
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]5069</div>
Reid Spencer443460a2006-11-09 21:15:49 +0000[diff] [blame]5070
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5071</div>
5072
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]5073<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5074<h3>
5075 <a name="convertops">Conversion Operations</a>
5076</h3>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5077
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5078<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5079
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5080<p>The instructions in this category are the conversion instructions (casting)
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5081 which all take a single operand and a type. They perform various bit
5082 conversions on the operand.</p>
5083
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]5084<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5085<h4>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5086 <a name="i_trunc">'<tt>trunc .. to</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5087</h4>
5088
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5089<div>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5090
5091<h5>Syntax:</h5>
5092<pre>
5093 &lt;result&gt; = trunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
5094</pre>
5095
5096<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5097<p>The '<tt>trunc</tt>' instruction truncates its operand to the
5098 type <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5099
5100<h5>Arguments:</h5>
Nadav Rotem502f1b92011-02-24 21:01:34 +0000[diff] [blame]5101<p>The '<tt>trunc</tt>' instruction takes a value to trunc, and a type to trunc it to.
5102 Both types must be of <a href="#t_integer">integer</a> types, or vectors
5103 of the same number of integers.
5104 The bit size of the <tt>value</tt> must be larger than
5105 the bit size of the destination type, <tt>ty2</tt>.
5106 Equal sized types are not allowed.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5107
5108<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5109<p>The '<tt>trunc</tt>' instruction truncates the high order bits
5110 in <tt>value</tt> and converts the remaining bits to <tt>ty2</tt>. Since the
5111 source size must be larger than the destination size, <tt>trunc</tt> cannot
5112 be a <i>no-op cast</i>. It will always truncate bits.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5113
5114<h5>Example:</h5>
5115<pre>
Nadav Rotem502f1b92011-02-24 21:01:34 +0000[diff] [blame]5116 %X = trunc i32 257 to i8 <i>; yields i8:1</i>
5117 %Y = trunc i32 123 to i1 <i>; yields i1:true</i>
5118 %Z = trunc i32 122 to i1 <i>; yields i1:false</i>
5119 %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]5120</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5121
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5122</div>
5123
5124<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5125<h4>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5126 <a name="i_zext">'<tt>zext .. to</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5127</h4>
5128
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5129<div>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5130
5131<h5>Syntax:</h5>
5132<pre>
5133 &lt;result&gt; = zext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
5134</pre>
5135
5136<h5>Overview:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5137<p>The '<tt>zext</tt>' instruction zero extends its operand to type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5138 <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5139
5140
5141<h5>Arguments:</h5>
Nadav Rotem25f2ac92011-02-20 12:37:50 +0000[diff] [blame]5142<p>The '<tt>zext</tt>' instruction takes a value to cast, and a type to cast it to.
5143 Both types must be of <a href="#t_integer">integer</a> types, or vectors
5144 of the same number of integers.
5145 The bit size of the <tt>value</tt> must be smaller than
5146 the bit size of the destination type,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5147 <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5148
5149<h5>Semantics:</h5>
5150<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]5151 bits until it reaches the size of the destination type, <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5152
Reid Spencer07c9c682007-01-12 15:46:11 +0000[diff] [blame]5153<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]5154
5155<h5>Example:</h5>
5156<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]5157 %X = zext i32 257 to i64 <i>; yields i64:257</i>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]5158 %Y = zext i1 true to i32 <i>; yields i32:1</i>
Nadav Rotem25f2ac92011-02-20 12:37:50 +0000[diff] [blame]5159 %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]5160</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5161
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5162</div>
5163
5164<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5165<h4>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5166 <a name="i_sext">'<tt>sext .. to</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5167</h4>
5168
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5169<div>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5170
5171<h5>Syntax:</h5>
5172<pre>
5173 &lt;result&gt; = sext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
5174</pre>
5175
5176<h5>Overview:</h5>
5177<p>The '<tt>sext</tt>' sign extends <tt>value</tt> to the type <tt>ty2</tt>.</p>
5178
5179<h5>Arguments:</h5>
Nadav Rotem502f1b92011-02-24 21:01:34 +0000[diff] [blame]5180<p>The '<tt>sext</tt>' instruction takes a value to cast, and a type to cast it to.
5181 Both types must be of <a href="#t_integer">integer</a> types, or vectors
5182 of the same number of integers.
5183 The bit size of the <tt>value</tt> must be smaller than
5184 the bit size of the destination type,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5185 <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5186
5187<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5188<p>The '<tt>sext</tt>' instruction performs a sign extension by copying the sign
5189 bit (highest order bit) of the <tt>value</tt> until it reaches the bit size
5190 of the type <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5191
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]5192<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]5193
5194<h5>Example:</h5>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5195<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]5196 %X = sext i8 -1 to i16 <i>; yields i16 :65535</i>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]5197 %Y = sext i1 true to i32 <i>; yields i32:-1</i>
Nadav Rotem502f1b92011-02-24 21:01:34 +0000[diff] [blame]5198 %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]5199</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5200
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5201</div>
5202
5203<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5204<h4>
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]5205 <a name="i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5206</h4>
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]5207
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5208<div>
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]5209
5210<h5>Syntax:</h5>
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]5211<pre>
5212 &lt;result&gt; = fptrunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
5213</pre>
5214
5215<h5>Overview:</h5>
5216<p>The '<tt>fptrunc</tt>' instruction truncates <tt>value</tt> to type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5217 <tt>ty2</tt>.</p>
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]5218
5219<h5>Arguments:</h5>
5220<p>The '<tt>fptrunc</tt>' instruction takes a <a href="#t_floating">floating
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5221 point</a> value to cast and a <a href="#t_floating">floating point</a> type
5222 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]5223 <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]5224 <i>no-op cast</i>.</p>
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]5225
5226<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5227<p>The '<tt>fptrunc</tt>' instruction truncates a <tt>value</tt> from a larger
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5228 <a href="#t_floating">floating point</a> type to a smaller
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5229 <a href="#t_floating">floating point</a> type. If the value cannot fit
5230 within the destination type, <tt>ty2</tt>, then the results are
5231 undefined.</p>
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]5232
5233<h5>Example:</h5>
5234<pre>
5235 %X = fptrunc double 123.0 to float <i>; yields float:123.0</i>
5236 %Y = fptrunc double 1.0E+300 to float <i>; yields undefined</i>
5237</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5238
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]5239</div>
5240
5241<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5242<h4>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5243 <a name="i_fpext">'<tt>fpext .. to</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5244</h4>
5245
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5246<div>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5247
5248<h5>Syntax:</h5>
5249<pre>
5250 &lt;result&gt; = fpext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
5251</pre>
5252
5253<h5>Overview:</h5>
5254<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]5255 floating point value.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5256
5257<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5258<p>The '<tt>fpext</tt>' instruction takes a
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5259 <a href="#t_floating">floating point</a> <tt>value</tt> to cast, and
5260 a <a href="#t_floating">floating point</a> type to cast it to. The source
5261 type must be smaller than the destination type.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5262
5263<h5>Semantics:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]5264<p>The '<tt>fpext</tt>' instruction extends the <tt>value</tt> from a smaller
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5265 <a href="#t_floating">floating point</a> type to a larger
5266 <a href="#t_floating">floating point</a> type. The <tt>fpext</tt> cannot be
5267 used to make a <i>no-op cast</i> because it always changes bits. Use
5268 <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]5269
5270<h5>Example:</h5>
5271<pre>
Nick Lewycky9feca672011-03-31 18:20:19 +0000[diff] [blame]5272 %X = fpext float 3.125 to double <i>; yields double:3.125000e+00</i>
5273 %Y = fpext double %X to fp128 <i>; yields fp128:0xL00000000000000004000900000000000</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5274</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5275
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5276</div>
5277
5278<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5279<h4>
Reid Spencer2eadb532007-01-21 00:29:26 +0000[diff] [blame]5280 <a name="i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5281</h4>
5282
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5283<div>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5284
5285<h5>Syntax:</h5>
5286<pre>
Reid Spencer753163d2007-07-31 14:40:14 +0000[diff] [blame]5287 &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]5288</pre>
5289
5290<h5>Overview:</h5>
Reid Spencer753163d2007-07-31 14:40:14 +0000[diff] [blame]5291<p>The '<tt>fptoui</tt>' converts a floating point <tt>value</tt> to its
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5292 unsigned integer equivalent of type <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5293
5294<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5295<p>The '<tt>fptoui</tt>' instruction takes a value to cast, which must be a
5296 scalar or vector <a href="#t_floating">floating point</a> value, and a type
5297 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
5298 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
5299 vector integer type with the same number of elements as <tt>ty</tt></p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5300
5301<h5>Semantics:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5302<p>The '<tt>fptoui</tt>' instruction converts its
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5303 <a href="#t_floating">floating point</a> operand into the nearest (rounding
5304 towards zero) unsigned integer value. If the value cannot fit
5305 in <tt>ty2</tt>, the results are undefined.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5306
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5307<h5>Example:</h5>
5308<pre>
Reid Spencer753163d2007-07-31 14:40:14 +0000[diff] [blame]5309 %X = fptoui double 123.0 to i32 <i>; yields i32:123</i>
Chris Lattner5b95a172007-09-22 03:17:52 +0000[diff] [blame]5310 %Y = fptoui float 1.0E+300 to i1 <i>; yields undefined:1</i>
Gabor Greiff50fd572009-10-28 09:21:30 +0000[diff] [blame]5311 %Z = fptoui float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5312</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5313
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5314</div>
5315
5316<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5317<h4>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]5318 <a name="i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5319</h4>
5320
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5321<div>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5322
5323<h5>Syntax:</h5>
5324<pre>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]5325 &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]5326</pre>
5327
5328<h5>Overview:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5329<p>The '<tt>fptosi</tt>' instruction converts
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5330 <a href="#t_floating">floating point</a> <tt>value</tt> to
5331 type <tt>ty2</tt>.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5332
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]5333<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5334<p>The '<tt>fptosi</tt>' instruction takes a value to cast, which must be a
5335 scalar or vector <a href="#t_floating">floating point</a> value, and a type
5336 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
5337 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
5338 vector integer type with the same number of elements as <tt>ty</tt></p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5339
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]5340<h5>Semantics:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5341<p>The '<tt>fptosi</tt>' instruction converts its
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5342 <a href="#t_floating">floating point</a> operand into the nearest (rounding
5343 towards zero) signed integer value. If the value cannot fit in <tt>ty2</tt>,
5344 the results are undefined.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5345
Chris Lattner70de6632001-07-09 00:26:23 +0000[diff] [blame]5346<h5>Example:</h5>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5347<pre>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]5348 %X = fptosi double -123.0 to i32 <i>; yields i32:-123</i>
Chris Lattner5b95a172007-09-22 03:17:52 +0000[diff] [blame]5349 %Y = fptosi float 1.0E-247 to i1 <i>; yields undefined:1</i>
Gabor Greiff50fd572009-10-28 09:21:30 +0000[diff] [blame]5350 %Z = fptosi float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5351</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5352
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5353</div>
5354
5355<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5356<h4>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]5357 <a name="i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5358</h4>
5359
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5360<div>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5361
5362<h5>Syntax:</h5>
5363<pre>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]5364 &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]5365</pre>
5366
5367<h5>Overview:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]5368<p>The '<tt>uitofp</tt>' instruction regards <tt>value</tt> as an unsigned
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5369 integer and converts that value to the <tt>ty2</tt> type.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5370
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5371<h5>Arguments:</h5>
Nate Begemand4d45c22007-11-17 03:58:34 +0000[diff] [blame]5372<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]5373 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
5374 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
5375 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
5376 floating point type with the same number of elements as <tt>ty</tt></p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5377
5378<h5>Semantics:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]5379<p>The '<tt>uitofp</tt>' instruction interprets its operand as an unsigned
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5380 integer quantity and converts it to the corresponding floating point
5381 value. If the value cannot fit in the floating point value, the results are
5382 undefined.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5383
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5384<h5>Example:</h5>
5385<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]5386 %X = uitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]5387 %Y = uitofp i8 -1 to double <i>; yields double:255.0</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5388</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5389
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5390</div>
5391
5392<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5393<h4>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]5394 <a name="i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5395</h4>
5396
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5397<div>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5398
5399<h5>Syntax:</h5>
5400<pre>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]5401 &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]5402</pre>
5403
5404<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5405<p>The '<tt>sitofp</tt>' instruction regards <tt>value</tt> as a signed integer
5406 and converts that value to the <tt>ty2</tt> type.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5407
5408<h5>Arguments:</h5>
Nate Begemand4d45c22007-11-17 03:58:34 +0000[diff] [blame]5409<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]5410 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
5411 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
5412 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
5413 floating point type with the same number of elements as <tt>ty</tt></p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5414
5415<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5416<p>The '<tt>sitofp</tt>' instruction interprets its operand as a signed integer
5417 quantity and converts it to the corresponding floating point value. If the
5418 value cannot fit in the floating point value, the results are undefined.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5419
5420<h5>Example:</h5>
5421<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]5422 %X = sitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]5423 %Y = sitofp i8 -1 to double <i>; yields double:-1.0</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5424</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5425
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5426</div>
5427
5428<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5429<h4>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]5430 <a name="i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5431</h4>
5432
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5433<div>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]5434
5435<h5>Syntax:</h5>
5436<pre>
5437 &lt;result&gt; = ptrtoint &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
5438</pre>
5439
5440<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5441<p>The '<tt>ptrtoint</tt>' instruction converts the pointer <tt>value</tt> to
5442 the integer type <tt>ty2</tt>.</p>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]5443
5444<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5445<p>The '<tt>ptrtoint</tt>' instruction takes a <tt>value</tt> to cast, which
5446 must be a <a href="#t_pointer">pointer</a> value, and a type to cast it to
5447 <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]5448
5449<h5>Semantics:</h5>
5450<p>The '<tt>ptrtoint</tt>' instruction converts <tt>value</tt> to integer type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5451 <tt>ty2</tt> by interpreting the pointer value as an integer and either
5452 truncating or zero extending that value to the size of the integer type. If
5453 <tt>value</tt> is smaller than <tt>ty2</tt> then a zero extension is done. If
5454 <tt>value</tt> is larger than <tt>ty2</tt> then a truncation is done. If they
5455 are the same size, then nothing is done (<i>no-op cast</i>) other than a type
5456 change.</p>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]5457
5458<h5>Example:</h5>
5459<pre>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5460 %X = ptrtoint i32* %X to i8 <i>; yields truncation on 32-bit architecture</i>
5461 %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]5462</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5463
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]5464</div>
5465
5466<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5467<h4>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]5468 <a name="i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5469</h4>
5470
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5471<div>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]5472
5473<h5>Syntax:</h5>
5474<pre>
5475 &lt;result&gt; = inttoptr &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
5476</pre>
5477
5478<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5479<p>The '<tt>inttoptr</tt>' instruction converts an integer <tt>value</tt> to a
5480 pointer type, <tt>ty2</tt>.</p>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]5481
5482<h5>Arguments:</h5>
Duncan Sands16f122e2007-03-30 12:22:09 +0000[diff] [blame]5483<p>The '<tt>inttoptr</tt>' instruction takes an <a href="#t_integer">integer</a>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5484 value to cast, and a type to cast it to, which must be a
5485 <a href="#t_pointer">pointer</a> type.</p>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]5486
5487<h5>Semantics:</h5>
5488<p>The '<tt>inttoptr</tt>' instruction converts <tt>value</tt> to type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5489 <tt>ty2</tt> by applying either a zero extension or a truncation depending on
5490 the size of the integer <tt>value</tt>. If <tt>value</tt> is larger than the
5491 size of a pointer then a truncation is done. If <tt>value</tt> is smaller
5492 than the size of a pointer then a zero extension is done. If they are the
5493 same size, nothing is done (<i>no-op cast</i>).</p>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]5494
5495<h5>Example:</h5>
5496<pre>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5497 %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]5498 %Y = inttoptr i32 255 to i32* <i>; yields no-op on 32-bit architecture</i>
5499 %Z = inttoptr i64 0 to i32* <i>; yields truncation on 32-bit architecture</i>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]5500</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5501
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]5502</div>
5503
5504<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5505<h4>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]5506 <a name="i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5507</h4>
5508
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5509<div>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5510
5511<h5>Syntax:</h5>
5512<pre>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]5513 &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]5514</pre>
5515
5516<h5>Overview:</h5>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]5517<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5518 <tt>ty2</tt> without changing any bits.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5519
5520<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5521<p>The '<tt>bitcast</tt>' instruction takes a value to cast, which must be a
5522 non-aggregate first class value, and a type to cast it to, which must also be
5523 a non-aggregate <a href="#t_firstclass">first class</a> type. The bit sizes
5524 of <tt>value</tt> and the destination type, <tt>ty2</tt>, must be
5525 identical. If the source type is a pointer, the destination type must also be
5526 a pointer. This instruction supports bitwise conversion of vectors to
5527 integers and to vectors of other types (as long as they have the same
5528 size).</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5529
5530<h5>Semantics:</h5>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]5531<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5532 <tt>ty2</tt>. It is always a <i>no-op cast</i> because no bits change with
5533 this conversion. The conversion is done as if the <tt>value</tt> had been
5534 stored to memory and read back as type <tt>ty2</tt>. Pointer types may only
5535 be converted to other pointer types with this instruction. To convert
5536 pointers to other types, use the <a href="#i_inttoptr">inttoptr</a> or
5537 <a href="#i_ptrtoint">ptrtoint</a> instructions first.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5538
5539<h5>Example:</h5>
5540<pre>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5541 %X = bitcast i8 255 to i8 <i>; yields i8 :-1</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]5542 %Y = bitcast i32* %x to sint* <i>; yields sint*:%x</i>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5543 %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]5544</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5545
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5546</div>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5547
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5548</div>
5549
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5550<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5551<h3>
5552 <a name="otherops">Other Operations</a>
5553</h3>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5554
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5555<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5556
5557<p>The instructions in this category are the "miscellaneous" instructions, which
5558 defy better classification.</p>
5559
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5560<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5561<h4>
5562 <a name="i_icmp">'<tt>icmp</tt>' Instruction</a>
5563</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5564
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5565<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5566
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5567<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5568<pre>
5569 &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]5570</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5571
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5572<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5573<p>The '<tt>icmp</tt>' instruction returns a boolean value or a vector of
5574 boolean values based on comparison of its two integer, integer vector, or
5575 pointer operands.</p>
5576
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5577<h5>Arguments:</h5>
5578<p>The '<tt>icmp</tt>' instruction takes three operands. The first operand is
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5579 the condition code indicating the kind of comparison to perform. It is not a
5580 value, just a keyword. The possible condition code are:</p>
5581
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5582<ol>
5583 <li><tt>eq</tt>: equal</li>
5584 <li><tt>ne</tt>: not equal </li>
5585 <li><tt>ugt</tt>: unsigned greater than</li>
5586 <li><tt>uge</tt>: unsigned greater or equal</li>
5587 <li><tt>ult</tt>: unsigned less than</li>
5588 <li><tt>ule</tt>: unsigned less or equal</li>
5589 <li><tt>sgt</tt>: signed greater than</li>
5590 <li><tt>sge</tt>: signed greater or equal</li>
5591 <li><tt>slt</tt>: signed less than</li>
5592 <li><tt>sle</tt>: signed less or equal</li>
5593</ol>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5594
Chris Lattnerc0f423a2007-01-15 01:54:13 +0000[diff] [blame]5595<p>The remaining two arguments must be <a href="#t_integer">integer</a> or
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5596 <a href="#t_pointer">pointer</a> or integer <a href="#t_vector">vector</a>
5597 typed. They must also be identical types.</p>
5598
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5599<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5600<p>The '<tt>icmp</tt>' compares <tt>op1</tt> and <tt>op2</tt> according to the
5601 condition code given as <tt>cond</tt>. The comparison performed always yields
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]5602 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]5603 result, as follows:</p>
5604
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5605<ol>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5606 <li><tt>eq</tt>: yields <tt>true</tt> if the operands are equal,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5607 <tt>false</tt> otherwise. No sign interpretation is necessary or
5608 performed.</li>
5609
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5610 <li><tt>ne</tt>: yields <tt>true</tt> if the operands are unequal,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5611 <tt>false</tt> otherwise. No sign interpretation is necessary or
5612 performed.</li>
5613
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5614 <li><tt>ugt</tt>: interprets the operands as unsigned values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5615 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
5616
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5617 <li><tt>uge</tt>: interprets the operands as unsigned values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5618 <tt>true</tt> if <tt>op1</tt> is greater than or equal
5619 to <tt>op2</tt>.</li>
5620
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5621 <li><tt>ult</tt>: interprets the operands as unsigned values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5622 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
5623
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5624 <li><tt>ule</tt>: interprets the operands as unsigned values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5625 <tt>true</tt> if <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
5626
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5627 <li><tt>sgt</tt>: interprets the operands as signed values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5628 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
5629
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5630 <li><tt>sge</tt>: interprets the operands as signed values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5631 <tt>true</tt> if <tt>op1</tt> is greater than or equal
5632 to <tt>op2</tt>.</li>
5633
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5634 <li><tt>slt</tt>: interprets the operands as signed values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5635 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
5636
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5637 <li><tt>sle</tt>: interprets the operands as signed values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5638 <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]5639</ol>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5640
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5641<p>If the operands are <a href="#t_pointer">pointer</a> typed, the pointer
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5642 values are compared as if they were integers.</p>
5643
5644<p>If the operands are integer vectors, then they are compared element by
5645 element. The result is an <tt>i1</tt> vector with the same number of elements
5646 as the values being compared. Otherwise, the result is an <tt>i1</tt>.</p>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5647
5648<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5649<pre>
5650 &lt;result&gt; = icmp eq i32 4, 5 <i>; yields: result=false</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]5651 &lt;result&gt; = icmp ne float* %X, %X <i>; yields: result=false</i>
5652 &lt;result&gt; = icmp ult i16 4, 5 <i>; yields: result=true</i>
5653 &lt;result&gt; = icmp sgt i16 4, 5 <i>; yields: result=false</i>
5654 &lt;result&gt; = icmp ule i16 -4, 5 <i>; yields: result=false</i>
5655 &lt;result&gt; = icmp sge i16 4, 5 <i>; yields: result=false</i>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5656</pre>
Dan Gohmana5127ab2009-01-22 01:39:38 +0000[diff] [blame]5657
5658<p>Note that the code generator does not yet support vector types with
5659 the <tt>icmp</tt> instruction.</p>
5660
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5661</div>
5662
5663<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5664<h4>
5665 <a name="i_fcmp">'<tt>fcmp</tt>' Instruction</a>
5666</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5667
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5668<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5669
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5670<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5671<pre>
5672 &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]5673</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5674
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5675<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5676<p>The '<tt>fcmp</tt>' instruction returns a boolean value or vector of boolean
5677 values based on comparison of its operands.</p>
5678
5679<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]5680(<a href="#t_integer"><tt>i1</tt></a>).</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5681
5682<p>If the operands are floating point vectors, then the result type is a vector
5683 of boolean with the same number of elements as the operands being
5684 compared.</p>
5685
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5686<h5>Arguments:</h5>
5687<p>The '<tt>fcmp</tt>' instruction takes three operands. The first operand is
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5688 the condition code indicating the kind of comparison to perform. It is not a
5689 value, just a keyword. The possible condition code are:</p>
5690
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5691<ol>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]5692 <li><tt>false</tt>: no comparison, always returns false</li>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5693 <li><tt>oeq</tt>: ordered and equal</li>
5694 <li><tt>ogt</tt>: ordered and greater than </li>
5695 <li><tt>oge</tt>: ordered and greater than or equal</li>
5696 <li><tt>olt</tt>: ordered and less than </li>
5697 <li><tt>ole</tt>: ordered and less than or equal</li>
5698 <li><tt>one</tt>: ordered and not equal</li>
5699 <li><tt>ord</tt>: ordered (no nans)</li>
5700 <li><tt>ueq</tt>: unordered or equal</li>
5701 <li><tt>ugt</tt>: unordered or greater than </li>
5702 <li><tt>uge</tt>: unordered or greater than or equal</li>
5703 <li><tt>ult</tt>: unordered or less than </li>
5704 <li><tt>ule</tt>: unordered or less than or equal</li>
5705 <li><tt>une</tt>: unordered or not equal</li>
5706 <li><tt>uno</tt>: unordered (either nans)</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]5707 <li><tt>true</tt>: no comparison, always returns true</li>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5708</ol>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5709
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5710<p><i>Ordered</i> means that neither operand is a QNAN while
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5711 <i>unordered</i> means that either operand may be a QNAN.</p>
5712
5713<p>Each of <tt>val1</tt> and <tt>val2</tt> arguments must be either
5714 a <a href="#t_floating">floating point</a> type or
5715 a <a href="#t_vector">vector</a> of floating point type. They must have
5716 identical types.</p>
5717
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5718<h5>Semantics:</h5>
Gabor Greif0f75ad02008-08-07 21:46:00 +0000[diff] [blame]5719<p>The '<tt>fcmp</tt>' instruction compares <tt>op1</tt> and <tt>op2</tt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5720 according to the condition code given as <tt>cond</tt>. If the operands are
5721 vectors, then the vectors are compared element by element. Each comparison
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]5722 performed always yields an <a href="#t_integer">i1</a> result, as
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5723 follows:</p>
5724
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5725<ol>
5726 <li><tt>false</tt>: always yields <tt>false</tt>, regardless of operands.</li>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5727
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5728 <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]5729 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
5730
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]5731 <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]5732 <tt>op1</tt> is greater than <tt>op2</tt>.</li>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5733
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5734 <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]5735 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
5736
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5737 <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]5738 <tt>op1</tt> is less than <tt>op2</tt>.</li>
5739
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5740 <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]5741 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
5742
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5743 <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]5744 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
5745
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]5746 <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]5747
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5748 <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]5749 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
5750
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5751 <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]5752 <tt>op1</tt> is greater than <tt>op2</tt>.</li>
5753
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5754 <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]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>ult</tt>: yields <tt>true</tt> if either operand is a QNAN or
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>ule</tt>: yields <tt>true</tt> if either operand is a QNAN or
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>une</tt>: yields <tt>true</tt> if either operand is a QNAN or
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>uno</tt>: yields <tt>true</tt> if either operand is a QNAN.</li>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5767
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5768 <li><tt>true</tt>: always yields <tt>true</tt>, regardless of operands.</li>
5769</ol>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5770
5771<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5772<pre>
5773 &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]5774 &lt;result&gt; = fcmp one float 4.0, 5.0 <i>; yields: result=true</i>
5775 &lt;result&gt; = fcmp olt float 4.0, 5.0 <i>; yields: result=true</i>
5776 &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]5777</pre>
Dan Gohmana5127ab2009-01-22 01:39:38 +0000[diff] [blame]5778
5779<p>Note that the code generator does not yet support vector types with
5780 the <tt>fcmp</tt> instruction.</p>
5781
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5782</div>
5783
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5784<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5785<h4>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]5786 <a name="i_phi">'<tt>phi</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5787</h4>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]5788
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5789<div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]5790
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5791<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5792<pre>
5793 &lt;result&gt; = phi &lt;ty&gt; [ &lt;val0&gt;, &lt;label0&gt;], ...
5794</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]5795
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5796<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5797<p>The '<tt>phi</tt>' instruction is used to implement the &#966; node in the
5798 SSA graph representing the function.</p>
5799
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5800<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5801<p>The type of the incoming values is specified with the first type field. After
5802 this, the '<tt>phi</tt>' instruction takes a list of pairs as arguments, with
5803 one pair for each predecessor basic block of the current block. Only values
5804 of <a href="#t_firstclass">first class</a> type may be used as the value
5805 arguments to the PHI node. Only labels may be used as the label
5806 arguments.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]5807
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5808<p>There must be no non-phi instructions between the start of a basic block and
5809 the PHI instructions: i.e. PHI instructions must be first in a basic
5810 block.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]5811
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5812<p>For the purposes of the SSA form, the use of each incoming value is deemed to
5813 occur on the edge from the corresponding predecessor block to the current
5814 block (but after any definition of an '<tt>invoke</tt>' instruction's return
5815 value on the same edge).</p>
Jay Foad1a4eea52009-06-03 10:20:10 +0000[diff] [blame]5816
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5817<h5>Semantics:</h5>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5818<p>At runtime, the '<tt>phi</tt>' instruction logically takes on the value
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5819 specified by the pair corresponding to the predecessor basic block that
5820 executed just prior to the current block.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]5821
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5822<h5>Example:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]5823<pre>
5824Loop: ; Infinite loop that counts from 0 on up...
5825 %indvar = phi i32 [ 0, %LoopHeader ], [ %nextindvar, %Loop ]
5826 %nextindvar = add i32 %indvar, 1
5827 br label %Loop
5828</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5829
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5830</div>
5831
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5832<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5833<h4>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5834 <a name="i_select">'<tt>select</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5835</h4>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5836
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5837<div>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5838
5839<h5>Syntax:</h5>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5840<pre>
Dan Gohmanc579d972008-09-09 01:02:47 +0000[diff] [blame]5841 &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>
5842
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]5843 <i>selty</i> is either i1 or {&lt;N x i1&gt;}
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5844</pre>
5845
5846<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5847<p>The '<tt>select</tt>' instruction is used to choose one value based on a
5848 condition, without branching.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5849
5850
5851<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5852<p>The '<tt>select</tt>' instruction requires an 'i1' value or a vector of 'i1'
5853 values indicating the condition, and two values of the
5854 same <a href="#t_firstclass">first class</a> type. If the val1/val2 are
5855 vectors and the condition is a scalar, then entire vectors are selected, not
5856 individual elements.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5857
5858<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5859<p>If the condition is an i1 and it evaluates to 1, the instruction returns the
5860 first value argument; otherwise, it returns the second value argument.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5861
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5862<p>If the condition is a vector of i1, then the value arguments must be vectors
5863 of the same size, and the selection is done element by element.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5864
5865<h5>Example:</h5>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5866<pre>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]5867 %X = select i1 true, i8 17, i8 42 <i>; yields i8:17</i>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5868</pre>
Dan Gohmana5127ab2009-01-22 01:39:38 +0000[diff] [blame]5869
5870<p>Note that the code generator does not yet support conditions
5871 with vector type.</p>
5872
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5873</div>
5874
Robert Bocchinof72fdfe2006-01-15 20:48:27 +0000[diff] [blame]5875<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5876<h4>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5877 <a name="i_call">'<tt>call</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5878</h4>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5879
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5880<div>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5881
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]5882<h5>Syntax:</h5>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5883<pre>
Devang Patel02256232008-10-07 17:48:33 +0000[diff] [blame]5884 &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]5885</pre>
5886
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]5887<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5888<p>The '<tt>call</tt>' instruction represents a simple function call.</p>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5889
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]5890<h5>Arguments:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5891<p>This instruction requires several arguments:</p>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5892
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]5893<ol>
Jeffrey Yasskinb8677462010-01-09 19:44:16 +0000[diff] [blame]5894 <li>The optional "tail" marker indicates that the callee function does not
5895 access any allocas or varargs in the caller. Note that calls may be
5896 marked "tail" even if they do not occur before
5897 a <a href="#i_ret"><tt>ret</tt></a> instruction. If the "tail" marker is
5898 present, the function call is eligible for tail call optimization,
5899 but <a href="CodeGenerator.html#tailcallopt">might not in fact be
Evan Cheng59676492010-03-08 21:05:02 +0000[diff] [blame]5900 optimized into a jump</a>. The code generator may optimize calls marked
5901 "tail" with either 1) automatic <a href="CodeGenerator.html#sibcallopt">
5902 sibling call optimization</a> when the caller and callee have
5903 matching signatures, or 2) forced tail call optimization when the
5904 following extra requirements are met:
Jeffrey Yasskinb8677462010-01-09 19:44:16 +0000[diff] [blame]5905 <ul>
5906 <li>Caller and callee both have the calling
5907 convention <tt>fastcc</tt>.</li>
5908 <li>The call is in tail position (ret immediately follows call and ret
5909 uses value of call or is void).</li>
5910 <li>Option <tt>-tailcallopt</tt> is enabled,
Dan Gohman6232f732010-03-02 01:08:11 +0000[diff] [blame]5911 or <code>llvm::GuaranteedTailCallOpt</code> is <code>true</code>.</li>
Jeffrey Yasskinb8677462010-01-09 19:44:16 +0000[diff] [blame]5912 <li><a href="CodeGenerator.html#tailcallopt">Platform specific
5913 constraints are met.</a></li>
5914 </ul>
5915 </li>
Devang Patel7e9b05e2008-10-06 18:50:38 +0000[diff] [blame]5916
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5917 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
5918 convention</a> the call should use. If none is specified, the call
Jeffrey Yasskinb8677462010-01-09 19:44:16 +0000[diff] [blame]5919 defaults to using C calling conventions. The calling convention of the
5920 call must match the calling convention of the target function, or else the
5921 behavior is undefined.</li>
Devang Patel7e9b05e2008-10-06 18:50:38 +0000[diff] [blame]5922
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5923 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
5924 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
5925 '<tt>inreg</tt>' attributes are valid here.</li>
5926
5927 <li>'<tt>ty</tt>': the type of the call instruction itself which is also the
5928 type of the return value. Functions that return no value are marked
5929 <tt><a href="#t_void">void</a></tt>.</li>
5930
5931 <li>'<tt>fnty</tt>': shall be the signature of the pointer to function value
5932 being invoked. The argument types must match the types implied by this
5933 signature. This type can be omitted if the function is not varargs and if
5934 the function type does not return a pointer to a function.</li>
5935
5936 <li>'<tt>fnptrval</tt>': An LLVM value containing a pointer to a function to
5937 be invoked. In most cases, this is a direct function invocation, but
5938 indirect <tt>call</tt>s are just as possible, calling an arbitrary pointer
5939 to function value.</li>
5940
5941 <li>'<tt>function args</tt>': argument list whose types match the function
Chris Lattner47f2a832010-03-02 06:36:51 +0000[diff] [blame]5942 signature argument types and parameter attributes. All arguments must be
5943 of <a href="#t_firstclass">first class</a> type. If the function
5944 signature indicates the function accepts a variable number of arguments,
5945 the extra arguments can be specified.</li>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5946
5947 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
5948 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
5949 '<tt>readnone</tt>' attributes are valid here.</li>
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]5950</ol>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5951
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]5952<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5953<p>The '<tt>call</tt>' instruction is used to cause control flow to transfer to
5954 a specified function, with its incoming arguments bound to the specified
5955 values. Upon a '<tt><a href="#i_ret">ret</a></tt>' instruction in the called
5956 function, control flow continues with the instruction after the function
5957 call, and the return value of the function is bound to the result
5958 argument.</p>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5959
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]5960<h5>Example:</h5>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5961<pre>
Nick Lewyckya9b13d52007-09-08 13:57:50 +0000[diff] [blame]5962 %retval = call i32 @test(i32 %argc)
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]5963 call i32 (i8*, ...)* @printf(i8* %msg, i32 12, i8 42) <i>; yields i32</i>
Chris Lattnerfb7c88d2008-03-21 17:24:17 +0000[diff] [blame]5964 %X = tail call i32 @foo() <i>; yields i32</i>
5965 %Y = tail call <a href="#callingconv">fastcc</a> i32 @foo() <i>; yields i32</i>
5966 call void %foo(i8 97 signext)
Devang Pateld6cff512008-03-10 20:49:15 +0000[diff] [blame]5967
5968 %struct.A = type { i32, i8 }
Devang Patel7e9b05e2008-10-06 18:50:38 +0000[diff] [blame]5969 %r = call %struct.A @foo() <i>; yields { 32, i8 }</i>
Dan Gohmancc3132e2008-10-04 19:00:07 +0000[diff] [blame]5970 %gr = extractvalue %struct.A %r, 0 <i>; yields i32</i>
5971 %gr1 = extractvalue %struct.A %r, 1 <i>; yields i8</i>
Chris Lattner6cbe8e92008-10-08 06:26:11 +0000[diff] [blame]5972 %Z = call void @foo() noreturn <i>; indicates that %foo never returns normally</i>
Matthijs Kooijmaneefa7df2008-10-07 10:03:45 +0000[diff] [blame]5973 %ZZ = call zeroext i32 @bar() <i>; Return value is %zero extended</i>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5974</pre>
5975
Dale Johannesen68f971b2009-09-24 18:38:21 +0000[diff] [blame]5976<p>llvm treats calls to some functions with names and arguments that match the
Dale Johannesen722212d2009-09-25 17:04:42 +0000[diff] [blame]5977standard C99 library as being the C99 library functions, and may perform
5978optimizations or generate code for them under that assumption. This is
5979something we'd like to change in the future to provide better support for
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]5980freestanding environments and non-C-based languages.</p>
Dale Johannesen68f971b2009-09-24 18:38:21 +0000[diff] [blame]5981
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5982</div>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5983
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5984<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5985<h4>
Chris Lattner33337472006-01-13 23:26:01 +0000[diff] [blame]5986 <a name="i_va_arg">'<tt>va_arg</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5987</h4>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5988
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5989<div>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5990
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]5991<h5>Syntax:</h5>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5992<pre>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]5993 &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]5994</pre>
5995
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]5996<h5>Overview:</h5>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]5997<p>The '<tt>va_arg</tt>' instruction is used to access arguments passed through
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5998 the "variable argument" area of a function call. It is used to implement the
5999 <tt>va_arg</tt> macro in C.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]6000
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]6001<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6002<p>This instruction takes a <tt>va_list*</tt> value and the type of the
6003 argument. It returns a value of the specified argument type and increments
6004 the <tt>va_list</tt> to point to the next argument. The actual type
6005 of <tt>va_list</tt> is target specific.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]6006
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]6007<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6008<p>The '<tt>va_arg</tt>' instruction loads an argument of the specified type
6009 from the specified <tt>va_list</tt> and causes the <tt>va_list</tt> to point
6010 to the next argument. For more information, see the variable argument
6011 handling <a href="#int_varargs">Intrinsic Functions</a>.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]6012
6013<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]6014 take a variable number of arguments, for example, the <tt>vfprintf</tt>
6015 function.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]6016
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6017<p><tt>va_arg</tt> is an LLVM instruction instead of
6018 an <a href="#intrinsics">intrinsic function</a> because it takes a type as an
6019 argument.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]6020
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]6021<h5>Example:</h5>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]6022<p>See the <a href="#int_varargs">variable argument processing</a> section.</p>
6023
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6024<p>Note that the code generator does not yet fully support va_arg on many
6025 targets. Also, it does not currently support va_arg with aggregate types on
6026 any target.</p>
Dan Gohman3065b612009-01-12 23:12:39 +0000[diff] [blame]6027
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]6028</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]6029
Bill Wendlingbbcb7cd2011-08-02 21:52:38 +0000[diff] [blame]6030<!-- _______________________________________________________________________ -->
6031<h4>
6032 <a name="i_landingpad">'<tt>landingpad</tt>' Instruction</a>
6033</h4>
6034
6035<div>
6036
6037<h5>Syntax:</h5>
6038<pre>
Bill Wendling49bfb122011-08-08 08:06:05 +0000[diff] [blame]6039 &lt;resultval&gt; = landingpad &lt;somety&gt; personality &lt;type&gt; &lt;pers_fn&gt; &lt;clause&gt;+
6040 &lt;resultval&gt; = landingpad &lt;somety&gt; personality &lt;type&gt; &lt;pers_fn&gt; cleanup &lt;clause&gt;*
6041
Bill Wendlingbbcb7cd2011-08-02 21:52:38 +0000[diff] [blame]6042 &lt;clause&gt; := catch &lt;type&gt; &lt;value&gt;
Bill Wendlingfae14752011-08-12 20:24:12 +0000[diff] [blame]6043 &lt;clause&gt; := filter &lt;array constant type&gt; &lt;array constant&gt;
Bill Wendlingbbcb7cd2011-08-02 21:52:38 +0000[diff] [blame]6044</pre>
6045
6046<h5>Overview:</h5>
6047<p>The '<tt>landingpad</tt>' instruction is used by
6048 <a href="ExceptionHandling.html#overview">LLVM's exception handling
6049 system</a> to specify that a basic block is a landing pad &mdash; one where
6050 the exception lands, and corresponds to the code found in the
6051 <i><tt>catch</tt></i> portion of a <i><tt>try/catch</tt></i> sequence. It
6052 defines values supplied by the personality function (<tt>pers_fn</tt>) upon
6053 re-entry to the function. The <tt>resultval</tt> has the
6054 type <tt>somety</tt>.</p>
6055
6056<h5>Arguments:</h5>
6057<p>This instruction takes a <tt>pers_fn</tt> value. This is the personality
6058 function associated with the unwinding mechanism. The optional
6059 <tt>cleanup</tt> flag indicates that the landing pad block is a cleanup.</p>
6060
6061<p>A <tt>clause</tt> begins with the clause type &mdash; <tt>catch</tt>
Bill Wendlingfae14752011-08-12 20:24:12 +0000[diff] [blame]6062 or <tt>filter</tt> &mdash; and contains the global variable representing the
6063 "type" that may be caught or filtered respectively. Unlike the
6064 <tt>catch</tt> clause, the <tt>filter</tt> clause takes an array constant as
6065 its argument. Use "<tt>[0 x i8**] undef</tt>" for a filter which cannot
6066 throw. The '<tt>landingpad</tt>' instruction must contain <em>at least</em>
Bill Wendlingbbcb7cd2011-08-02 21:52:38 +0000[diff] [blame]6067 one <tt>clause</tt> or the <tt>cleanup</tt> flag.</p>
6068
6069<h5>Semantics:</h5>
6070<p>The '<tt>landingpad</tt>' instruction defines the values which are set by the
6071 personality function (<tt>pers_fn</tt>) upon re-entry to the function, and
6072 therefore the "result type" of the <tt>landingpad</tt> instruction. As with
6073 calling conventions, how the personality function results are represented in
6074 LLVM IR is target specific.</p>
6075
Bill Wendling0524b8d2011-08-03 17:17:06 +0000[diff] [blame]6076<p>The clauses are applied in order from top to bottom. If two
6077 <tt>landingpad</tt> instructions are merged together through inlining, the
Bill Wendlinga503fc02011-08-08 07:58:58 +0000[diff] [blame]6078 clauses from the calling function are appended to the list of clauses.</p>
Bill Wendling0524b8d2011-08-03 17:17:06 +0000[diff] [blame]6079
Bill Wendlingbbcb7cd2011-08-02 21:52:38 +0000[diff] [blame]6080<p>The <tt>landingpad</tt> instruction has several restrictions:</p>
6081
6082<ul>
6083 <li>A landing pad block is a basic block which is the unwind destination of an
6084 '<tt>invoke</tt>' instruction.</li>
6085 <li>A landing pad block must have a '<tt>landingpad</tt>' instruction as its
6086 first non-PHI instruction.</li>
6087 <li>There can be only one '<tt>landingpad</tt>' instruction within the landing
6088 pad block.</li>
6089 <li>A basic block that is not a landing pad block may not include a
6090 '<tt>landingpad</tt>' instruction.</li>
6091 <li>All '<tt>landingpad</tt>' instructions in a function must have the same
6092 personality function.</li>
6093</ul>
6094
6095<h5>Example:</h5>
6096<pre>
6097 ;; A landing pad which can catch an integer.
6098 %res = landingpad { i8*, i32 } personality i32 (...)* @__gxx_personality_v0
6099 catch i8** @_ZTIi
6100 ;; A landing pad that is a cleanup.
6101 %res = landingpad { i8*, i32 } personality i32 (...)* @__gxx_personality_v0
Bill Wendlingfae14752011-08-12 20:24:12 +0000[diff] [blame]6102 cleanup
Bill Wendlingbbcb7cd2011-08-02 21:52:38 +0000[diff] [blame]6103 ;; A landing pad which can catch an integer and can only throw a double.
6104 %res = landingpad { i8*, i32 } personality i32 (...)* @__gxx_personality_v0
6105 catch i8** @_ZTIi
Bill Wendlingfae14752011-08-12 20:24:12 +0000[diff] [blame]6106 filter [1 x i8**] [@_ZTId]
Bill Wendlingbbcb7cd2011-08-02 21:52:38 +0000[diff] [blame]6107</pre>
6108
6109</div>
6110
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6111</div>
6112
6113</div>
6114
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]6115<!-- *********************************************************************** -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6116<h2><a name="intrinsics">Intrinsic Functions</a></h2>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]6117<!-- *********************************************************************** -->
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]6118
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6119<div>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6120
6121<p>LLVM supports the notion of an "intrinsic function". These functions have
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6122 well known names and semantics and are required to follow certain
6123 restrictions. Overall, these intrinsics represent an extension mechanism for
6124 the LLVM language that does not require changing all of the transformations
6125 in LLVM when adding to the language (or the bitcode reader/writer, the
6126 parser, etc...).</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6127
John Criswell88190562005-05-16 16:17:45 +0000[diff] [blame]6128<p>Intrinsic function names must all start with an "<tt>llvm.</tt>" prefix. This
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6129 prefix is reserved in LLVM for intrinsic names; thus, function names may not
6130 begin with this prefix. Intrinsic functions must always be external
6131 functions: you cannot define the body of intrinsic functions. Intrinsic
6132 functions may only be used in call or invoke instructions: it is illegal to
6133 take the address of an intrinsic function. Additionally, because intrinsic
6134 functions are part of the LLVM language, it is required if any are added that
6135 they be documented here.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6136
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6137<p>Some intrinsic functions can be overloaded, i.e., the intrinsic represents a
6138 family of functions that perform the same operation but on different data
6139 types. Because LLVM can represent over 8 million different integer types,
6140 overloading is used commonly to allow an intrinsic function to operate on any
6141 integer type. One or more of the argument types or the result type can be
6142 overloaded to accept any integer type. Argument types may also be defined as
6143 exactly matching a previous argument's type or the result type. This allows
6144 an intrinsic function which accepts multiple arguments, but needs all of them
6145 to be of the same type, to only be overloaded with respect to a single
6146 argument or the result.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6147
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6148<p>Overloaded intrinsics will have the names of its overloaded argument types
6149 encoded into its function name, each preceded by a period. Only those types
6150 which are overloaded result in a name suffix. Arguments whose type is matched
6151 against another type do not. For example, the <tt>llvm.ctpop</tt> function
6152 can take an integer of any width and returns an integer of exactly the same
6153 integer width. This leads to a family of functions such as
6154 <tt>i8 @llvm.ctpop.i8(i8 %val)</tt> and <tt>i29 @llvm.ctpop.i29(i29
6155 %val)</tt>. Only one type, the return type, is overloaded, and only one type
6156 suffix is required. Because the argument's type is matched against the return
6157 type, it does not require its own name suffix.</p>
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]6158
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]6159<p>To learn how to add an intrinsic function, please see the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6160 <a href="ExtendingLLVM.html">Extending LLVM Guide</a>.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6161
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]6162<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6163<h3>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]6164 <a name="int_varargs">Variable Argument Handling Intrinsics</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6165</h3>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]6166
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6167<div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6168
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6169<p>Variable argument support is defined in LLVM with
6170 the <a href="#i_va_arg"><tt>va_arg</tt></a> instruction and these three
6171 intrinsic functions. These functions are related to the similarly named
6172 macros defined in the <tt>&lt;stdarg.h&gt;</tt> header file.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6173
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6174<p>All of these functions operate on arguments that use a target-specific value
6175 type "<tt>va_list</tt>". The LLVM assembly language reference manual does
6176 not define what this type is, so all transformations should be prepared to
6177 handle these functions regardless of the type used.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6178
Chris Lattner30b868d2006-05-15 17:26:46 +0000[diff] [blame]6179<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]6180 instruction and the variable argument handling intrinsic functions are
6181 used.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6182
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]6183<pre class="doc_code">
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]6184define i32 @test(i32 %X, ...) {
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6185 ; Initialize variable argument processing
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]6186 %ap = alloca i8*
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]6187 %ap2 = bitcast i8** %ap to i8*
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]6188 call void @llvm.va_start(i8* %ap2)
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6189
6190 ; Read a single integer argument
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]6191 %tmp = va_arg i8** %ap, i32
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6192
6193 ; Demonstrate usage of llvm.va_copy and llvm.va_end
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]6194 %aq = alloca i8*
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]6195 %aq2 = bitcast i8** %aq to i8*
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]6196 call void @llvm.va_copy(i8* %aq2, i8* %ap2)
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]6197 call void @llvm.va_end(i8* %aq2)
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6198
6199 ; Stop processing of arguments.
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]6200 call void @llvm.va_end(i8* %ap2)
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]6201 ret i32 %tmp
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6202}
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]6203
6204declare void @llvm.va_start(i8*)
6205declare void @llvm.va_copy(i8*, i8*)
6206declare void @llvm.va_end(i8*)
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6207</pre>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]6208
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]6209<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6210<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6211 <a name="int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6212</h4>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]6213
6214
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6215<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6216
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]6217<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6218<pre>
6219 declare void %llvm.va_start(i8* &lt;arglist&gt;)
6220</pre>
6221
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]6222<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6223<p>The '<tt>llvm.va_start</tt>' intrinsic initializes <tt>*&lt;arglist&gt;</tt>
6224 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]6225
6226<h5>Arguments:</h5>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]6227<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]6228
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]6229<h5>Semantics:</h5>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]6230<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]6231 macro available in C. In a target-dependent way, it initializes
6232 the <tt>va_list</tt> element to which the argument points, so that the next
6233 call to <tt>va_arg</tt> will produce the first variable argument passed to
6234 the function. Unlike the C <tt>va_start</tt> macro, this intrinsic does not
6235 need to know the last argument of the function as the compiler can figure
6236 that out.</p>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]6237
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]6238</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]6239
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]6240<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6241<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6242 <a name="int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6243</h4>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]6244
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6245<div>
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]6246
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6247<h5>Syntax:</h5>
6248<pre>
6249 declare void @llvm.va_end(i8* &lt;arglist&gt;)
6250</pre>
6251
6252<h5>Overview:</h5>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]6253<p>The '<tt>llvm.va_end</tt>' intrinsic destroys <tt>*&lt;arglist&gt;</tt>,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6254 which has been initialized previously
6255 with <tt><a href="#int_va_start">llvm.va_start</a></tt>
6256 or <tt><a href="#i_va_copy">llvm.va_copy</a></tt>.</p>
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]6257
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]6258<h5>Arguments:</h5>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]6259<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]6260
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]6261<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]6262<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]6263 macro available in C. In a target-dependent way, it destroys
6264 the <tt>va_list</tt> element to which the argument points. Calls
6265 to <a href="#int_va_start"><tt>llvm.va_start</tt></a>
6266 and <a href="#int_va_copy"> <tt>llvm.va_copy</tt></a> must be matched exactly
6267 with calls to <tt>llvm.va_end</tt>.</p>
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]6268
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]6269</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]6270
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]6271<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6272<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6273 <a name="int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6274</h4>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]6275
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6276<div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6277
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]6278<h5>Syntax:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6279<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]6280 declare void @llvm.va_copy(i8* &lt;destarglist&gt;, i8* &lt;srcarglist&gt;)
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6281</pre>
6282
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]6283<h5>Overview:</h5>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]6284<p>The '<tt>llvm.va_copy</tt>' intrinsic copies the current argument position
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6285 from the source argument list to the destination argument list.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6286
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]6287<h5>Arguments:</h5>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]6288<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]6289 The second argument is a pointer to a <tt>va_list</tt> element to copy
6290 from.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6291
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]6292<h5>Semantics:</h5>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]6293<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]6294 macro available in C. In a target-dependent way, it copies the
6295 source <tt>va_list</tt> element into the destination <tt>va_list</tt>
6296 element. This intrinsic is necessary because
6297 the <tt><a href="#int_va_start"> llvm.va_start</a></tt> intrinsic may be
6298 arbitrarily complex and require, for example, memory allocation.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6299
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]6300</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]6301
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6302</div>
6303
Bill Wendling537603b2011-07-31 06:45:03 +0000[diff] [blame]6304</div>
6305
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6306<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6307<h3>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6308 <a name="int_gc">Accurate Garbage Collection Intrinsics</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6309</h3>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6310
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6311<div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6312
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6313<p>LLVM support for <a href="GarbageCollection.html">Accurate Garbage
Chris Lattner67c37d12008-08-05 18:29:16 +0000[diff] [blame]6314Collection</a> (GC) requires the implementation and generation of these
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6315intrinsics. These intrinsics allow identification of <a href="#int_gcroot">GC
6316roots on the stack</a>, as well as garbage collector implementations that
6317require <a href="#int_gcread">read</a> and <a href="#int_gcwrite">write</a>
6318barriers. Front-ends for type-safe garbage collected languages should generate
6319these intrinsics to make use of the LLVM garbage collectors. For more details,
6320see <a href="GarbageCollection.html">Accurate Garbage Collection with
6321LLVM</a>.</p>
Christopher Lamb55c6d4f2007-12-17 01:00:21 +0000[diff] [blame]6322
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6323<p>The garbage collection intrinsics only operate on objects in the generic
6324 address space (address space zero).</p>
Christopher Lamb55c6d4f2007-12-17 01:00:21 +0000[diff] [blame]6325
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6326<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6327<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6328 <a name="int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6329</h4>
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
6333<h5>Syntax:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6334<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]6335 declare void @llvm.gcroot(i8** %ptrloc, i8* %metadata)
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6336</pre>
6337
6338<h5>Overview:</h5>
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]6339<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]6340 the code generator, and allows some metadata to be associated with it.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6341
6342<h5>Arguments:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6343<p>The first argument specifies the address of a stack object that contains the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6344 root pointer. The second pointer (which must be either a constant or a
6345 global value address) contains the meta-data to be associated with the
6346 root.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6347
6348<h5>Semantics:</h5>
Chris Lattner851b7712008-04-24 05:59:56 +0000[diff] [blame]6349<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]6350 location. At compile-time, the code generator generates information to allow
6351 the runtime to find the pointer at GC safe points. The '<tt>llvm.gcroot</tt>'
6352 intrinsic may only be used in a function which <a href="#gc">specifies a GC
6353 algorithm</a>.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6354
6355</div>
6356
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6357<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6358<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6359 <a name="int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6360</h4>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6361
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6362<div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6363
6364<h5>Syntax:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6365<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]6366 declare i8* @llvm.gcread(i8* %ObjPtr, i8** %Ptr)
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6367</pre>
6368
6369<h5>Overview:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6370<p>The '<tt>llvm.gcread</tt>' intrinsic identifies reads of references from heap
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6371 locations, allowing garbage collector implementations that require read
6372 barriers.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6373
6374<h5>Arguments:</h5>
Chris Lattnerf9228072006-03-14 20:02:51 +0000[diff] [blame]6375<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]6376 allocated from the garbage collector. The first object is a pointer to the
6377 start of the referenced object, if needed by the language runtime (otherwise
6378 null).</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6379
6380<h5>Semantics:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6381<p>The '<tt>llvm.gcread</tt>' intrinsic has the same semantics as a load
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6382 instruction, but may be replaced with substantially more complex code by the
6383 garbage collector runtime, as needed. The '<tt>llvm.gcread</tt>' intrinsic
6384 may only be used in a function which <a href="#gc">specifies a GC
6385 algorithm</a>.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6386
6387</div>
6388
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6389<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6390<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6391 <a name="int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6392</h4>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6393
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6394<div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6395
6396<h5>Syntax:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6397<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]6398 declare void @llvm.gcwrite(i8* %P1, i8* %Obj, i8** %P2)
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6399</pre>
6400
6401<h5>Overview:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6402<p>The '<tt>llvm.gcwrite</tt>' intrinsic identifies writes of references to heap
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6403 locations, allowing garbage collector implementations that require write
6404 barriers (such as generational or reference counting collectors).</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6405
6406<h5>Arguments:</h5>
Chris Lattnerf9228072006-03-14 20:02:51 +0000[diff] [blame]6407<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]6408 object to store it to, and the third is the address of the field of Obj to
6409 store to. If the runtime does not require a pointer to the object, Obj may
6410 be null.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6411
6412<h5>Semantics:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6413<p>The '<tt>llvm.gcwrite</tt>' intrinsic has the same semantics as a store
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6414 instruction, but may be replaced with substantially more complex code by the
6415 garbage collector runtime, as needed. The '<tt>llvm.gcwrite</tt>' intrinsic
6416 may only be used in a function which <a href="#gc">specifies a GC
6417 algorithm</a>.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6418
6419</div>
6420
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6421</div>
6422
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6423<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6424<h3>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6425 <a name="int_codegen">Code Generator Intrinsics</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6426</h3>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6427
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6428<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6429
6430<p>These intrinsics are provided by LLVM to expose special features that may
6431 only be implemented with code generator support.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6432
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6433<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6434<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6435 <a name="int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6436</h4>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6437
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6438<div>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6439
6440<h5>Syntax:</h5>
6441<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]6442 declare i8 *@llvm.returnaddress(i32 &lt;level&gt;)
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6443</pre>
6444
6445<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6446<p>The '<tt>llvm.returnaddress</tt>' intrinsic attempts to compute a
6447 target-specific value indicating the return address of the current function
6448 or one of its callers.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6449
6450<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6451<p>The argument to this intrinsic indicates which function to return the address
6452 for. Zero indicates the calling function, one indicates its caller, etc.
6453 The argument is <b>required</b> to be a constant integer value.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6454
6455<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6456<p>The '<tt>llvm.returnaddress</tt>' intrinsic either returns a pointer
6457 indicating the return address of the specified call frame, or zero if it
6458 cannot be identified. The value returned by this intrinsic is likely to be
6459 incorrect or 0 for arguments other than zero, so it should only be used for
6460 debugging purposes.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6461
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6462<p>Note that calling this intrinsic does not prevent function inlining or other
6463 aggressive transformations, so the value returned may not be that of the
6464 obvious source-language caller.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6465
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6466</div>
6467
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6468<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6469<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6470 <a name="int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6471</h4>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6472
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6473<div>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6474
6475<h5>Syntax:</h5>
6476<pre>
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]6477 declare i8* @llvm.frameaddress(i32 &lt;level&gt;)
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6478</pre>
6479
6480<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6481<p>The '<tt>llvm.frameaddress</tt>' intrinsic attempts to return the
6482 target-specific frame pointer value for the specified stack frame.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6483
6484<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6485<p>The argument to this intrinsic indicates which function to return the frame
6486 pointer for. Zero indicates the calling function, one indicates its caller,
6487 etc. The argument is <b>required</b> to be a constant integer value.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6488
6489<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6490<p>The '<tt>llvm.frameaddress</tt>' intrinsic either returns a pointer
6491 indicating the frame address of the specified call frame, or zero if it
6492 cannot be identified. The value returned by this intrinsic is likely to be
6493 incorrect or 0 for arguments other than zero, so it should only be used for
6494 debugging purposes.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6495
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6496<p>Note that calling this intrinsic does not prevent function inlining or other
6497 aggressive transformations, so the value returned may not be that of the
6498 obvious source-language caller.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6499
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6500</div>
6501
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]6502<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6503<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6504 <a name="int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6505</h4>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]6506
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6507<div>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]6508
6509<h5>Syntax:</h5>
6510<pre>
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]6511 declare i8* @llvm.stacksave()
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]6512</pre>
6513
6514<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6515<p>The '<tt>llvm.stacksave</tt>' intrinsic is used to remember the current state
6516 of the function stack, for use
6517 with <a href="#int_stackrestore"> <tt>llvm.stackrestore</tt></a>. This is
6518 useful for implementing language features like scoped automatic variable
6519 sized arrays in C99.</p>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]6520
6521<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6522<p>This intrinsic returns a opaque pointer value that can be passed
6523 to <a href="#int_stackrestore"><tt>llvm.stackrestore</tt></a>. When
6524 an <tt>llvm.stackrestore</tt> intrinsic is executed with a value saved
6525 from <tt>llvm.stacksave</tt>, it effectively restores the state of the stack
6526 to the state it was in when the <tt>llvm.stacksave</tt> intrinsic executed.
6527 In practice, this pops any <a href="#i_alloca">alloca</a> blocks from the
6528 stack that were allocated after the <tt>llvm.stacksave</tt> was executed.</p>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]6529
6530</div>
6531
6532<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6533<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6534 <a name="int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6535</h4>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]6536
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6537<div>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]6538
6539<h5>Syntax:</h5>
6540<pre>
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]6541 declare void @llvm.stackrestore(i8* %ptr)
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]6542</pre>
6543
6544<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6545<p>The '<tt>llvm.stackrestore</tt>' intrinsic is used to restore the state of
6546 the function stack to the state it was in when the
6547 corresponding <a href="#int_stacksave"><tt>llvm.stacksave</tt></a> intrinsic
6548 executed. This is useful for implementing language features like scoped
6549 automatic variable sized arrays in C99.</p>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]6550
6551<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6552<p>See the description
6553 for <a href="#int_stacksave"><tt>llvm.stacksave</tt></a>.</p>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]6554
6555</div>
6556
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]6557<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6558<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6559 <a name="int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6560</h4>
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]6561
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6562<div>
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]6563
6564<h5>Syntax:</h5>
6565<pre>
Bruno Cardoso Lopesdc9ff3a2011-06-14 04:58:37 +0000[diff] [blame]6566 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]6567</pre>
6568
6569<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6570<p>The '<tt>llvm.prefetch</tt>' intrinsic is a hint to the code generator to
6571 insert a prefetch instruction if supported; otherwise, it is a noop.
6572 Prefetches have no effect on the behavior of the program but can change its
6573 performance characteristics.</p>
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]6574
6575<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6576<p><tt>address</tt> is the address to be prefetched, <tt>rw</tt> is the
6577 specifier determining if the fetch should be for a read (0) or write (1),
6578 and <tt>locality</tt> is a temporal locality specifier ranging from (0) - no
Bruno Cardoso Lopesdc9ff3a2011-06-14 04:58:37 +0000[diff] [blame]6579 locality, to (3) - extremely local keep in cache. The <tt>cache type</tt>
6580 specifies whether the prefetch is performed on the data (1) or instruction (0)
6581 cache. The <tt>rw</tt>, <tt>locality</tt> and <tt>cache type</tt> arguments
6582 must be constant integers.</p>
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]6583
6584<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6585<p>This intrinsic does not modify the behavior of the program. In particular,
6586 prefetches cannot trap and do not produce a value. On targets that support
6587 this intrinsic, the prefetch can provide hints to the processor cache for
6588 better performance.</p>
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]6589
6590</div>
6591
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]6592<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6593<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6594 <a name="int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6595</h4>
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]6596
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6597<div>
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]6598
6599<h5>Syntax:</h5>
6600<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]6601 declare void @llvm.pcmarker(i32 &lt;id&gt;)
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]6602</pre>
6603
6604<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6605<p>The '<tt>llvm.pcmarker</tt>' intrinsic is a method to export a Program
6606 Counter (PC) in a region of code to simulators and other tools. The method
6607 is target specific, but it is expected that the marker will use exported
6608 symbols to transmit the PC of the marker. The marker makes no guarantees
6609 that it will remain with any specific instruction after optimizations. It is
6610 possible that the presence of a marker will inhibit optimizations. The
6611 intended use is to be inserted after optimizations to allow correlations of
6612 simulation runs.</p>
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]6613
6614<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6615<p><tt>id</tt> is a numerical id identifying the marker.</p>
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]6616
6617<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6618<p>This intrinsic does not modify the behavior of the program. Backends that do
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]6619 not support this intrinsic may ignore it.</p>
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]6620
6621</div>
6622
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]6623<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6624<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6625 <a name="int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6626</h4>
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]6627
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6628<div>
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]6629
6630<h5>Syntax:</h5>
6631<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]6632 declare i64 @llvm.readcyclecounter()
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]6633</pre>
6634
6635<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6636<p>The '<tt>llvm.readcyclecounter</tt>' intrinsic provides access to the cycle
6637 counter register (or similar low latency, high accuracy clocks) on those
6638 targets that support it. On X86, it should map to RDTSC. On Alpha, it
6639 should map to RPCC. As the backing counters overflow quickly (on the order
6640 of 9 seconds on alpha), this should only be used for small timings.</p>
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]6641
6642<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6643<p>When directly supported, reading the cycle counter should not modify any
6644 memory. Implementations are allowed to either return a application specific
6645 value or a system wide value. On backends without support, this is lowered
6646 to a constant 0.</p>
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]6647
6648</div>
6649
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6650</div>
6651
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6652<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6653<h3>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6654 <a name="int_libc">Standard C Library Intrinsics</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6655</h3>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6656
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6657<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6658
6659<p>LLVM provides intrinsics for a few important standard C library functions.
6660 These intrinsics allow source-language front-ends to pass information about
6661 the alignment of the pointer arguments to the code generator, providing
6662 opportunity for more efficient code generation.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6663
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6664<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6665<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6666 <a name="int_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6667</h4>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6668
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6669<div>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6670
6671<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6672<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]6673 integer bit width and for different address spaces. Not all targets support
6674 all bit widths however.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6675
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6676<pre>
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]6677 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]6678 i32 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]6679 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]6680 i64 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6681</pre>
6682
6683<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6684<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
6685 source location to the destination location.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6686
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6687<p>Note that, unlike the standard libc function, the <tt>llvm.memcpy.*</tt>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6688 intrinsics do not return a value, takes extra alignment/isvolatile arguments
6689 and the pointers can be in specified address spaces.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6690
6691<h5>Arguments:</h5>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6692
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6693<p>The first argument is a pointer to the destination, the second is a pointer
6694 to the source. The third argument is an integer argument specifying the
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6695 number of bytes to copy, the fourth argument is the alignment of the
6696 source and destination locations, and the fifth is a boolean indicating a
6697 volatile access.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6698
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]6699<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]6700 then the caller guarantees that both the source and destination pointers are
6701 aligned to that boundary.</p>
Chris Lattner4c67c482004-02-12 21:18:15 +0000[diff] [blame]6702
Jeffrey Yasskin5d284ae2010-04-26 21:21:24 +0000[diff] [blame]6703<p>If the <tt>isvolatile</tt> parameter is <tt>true</tt>, the
6704 <tt>llvm.memcpy</tt> call is a <a href="#volatile">volatile operation</a>.
6705 The detailed access behavior is not very cleanly specified and it is unwise
6706 to depend on it.</p>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6707
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6708<h5>Semantics:</h5>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6709
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6710<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
6711 source location to the destination location, which are not allowed to
6712 overlap. It copies "len" bytes of memory over. If the argument is known to
6713 be aligned to some boundary, this can be specified as the fourth argument,
6714 otherwise it should be set to 0 or 1.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6715
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6716</div>
6717
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6718<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6719<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6720 <a name="int_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6721</h4>
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6722
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6723<div>
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6724
6725<h5>Syntax:</h5>
Chris Lattnerdd708342008-11-21 16:42:48 +0000[diff] [blame]6726<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]6727 width and for different address space. Not all targets support all bit
6728 widths however.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6729
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6730<pre>
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]6731 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]6732 i32 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]6733 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]6734 i64 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6735</pre>
6736
6737<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6738<p>The '<tt>llvm.memmove.*</tt>' intrinsics move a block of memory from the
6739 source location to the destination location. It is similar to the
6740 '<tt>llvm.memcpy</tt>' intrinsic but allows the two memory locations to
6741 overlap.</p>
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6742
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6743<p>Note that, unlike the standard libc function, the <tt>llvm.memmove.*</tt>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6744 intrinsics do not return a value, takes extra alignment/isvolatile arguments
6745 and the pointers can be in specified address spaces.</p>
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6746
6747<h5>Arguments:</h5>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6748
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6749<p>The first argument is a pointer to the destination, the second is a pointer
6750 to the source. The third argument is an integer argument specifying the
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6751 number of bytes to copy, the fourth argument is the alignment of the
6752 source and destination locations, and the fifth is a boolean indicating a
6753 volatile access.</p>
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6754
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]6755<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]6756 then the caller guarantees that the source and destination pointers are
6757 aligned to that boundary.</p>
Chris Lattner4c67c482004-02-12 21:18:15 +0000[diff] [blame]6758
Jeffrey Yasskin5d284ae2010-04-26 21:21:24 +0000[diff] [blame]6759<p>If the <tt>isvolatile</tt> parameter is <tt>true</tt>, the
6760 <tt>llvm.memmove</tt> call is a <a href="#volatile">volatile operation</a>.
6761 The detailed access behavior is not very cleanly specified and it is unwise
6762 to depend on it.</p>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6763
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6764<h5>Semantics:</h5>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6765
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6766<p>The '<tt>llvm.memmove.*</tt>' intrinsics copy a block of memory from the
6767 source location to the destination location, which may overlap. It copies
6768 "len" bytes of memory over. If the argument is known to be aligned to some
6769 boundary, this can be specified as the fourth argument, otherwise it should
6770 be set to 0 or 1.</p>
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6771
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6772</div>
6773
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6774<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6775<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6776 <a name="int_memset">'<tt>llvm.memset.*</tt>' Intrinsics</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6777</h4>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6778
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6779<div>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6780
6781<h5>Syntax:</h5>
Chris Lattnerdd708342008-11-21 16:42:48 +0000[diff] [blame]6782<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]6783 width and for different address spaces. However, not all targets support all
6784 bit widths.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6785
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6786<pre>
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]6787 declare void @llvm.memset.p0i8.i32(i8* &lt;dest&gt;, i8 &lt;val&gt;,
Chris Lattner685db9d2010-04-08 00:54:34 +0000[diff] [blame]6788 i32 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]6789 declare void @llvm.memset.p0i8.i64(i8* &lt;dest&gt;, i8 &lt;val&gt;,
Chris Lattner685db9d2010-04-08 00:54:34 +0000[diff] [blame]6790 i64 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6791</pre>
6792
6793<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6794<p>The '<tt>llvm.memset.*</tt>' intrinsics fill a block of memory with a
6795 particular byte value.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6796
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6797<p>Note that, unlike the standard libc function, the <tt>llvm.memset</tt>
John Criswellad05ae42010-07-30 16:30:28 +0000[diff] [blame]6798 intrinsic does not return a value and takes extra alignment/volatile
6799 arguments. Also, the destination can be in an arbitrary address space.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6800
6801<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6802<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]6803 byte value with which to fill it, the third argument is an integer argument
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6804 specifying the number of bytes to fill, and the fourth argument is the known
John Criswellad05ae42010-07-30 16:30:28 +0000[diff] [blame]6805 alignment of the destination location.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6806
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]6807<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]6808 then the caller guarantees that the destination pointer is aligned to that
6809 boundary.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6810
Jeffrey Yasskin5d284ae2010-04-26 21:21:24 +0000[diff] [blame]6811<p>If the <tt>isvolatile</tt> parameter is <tt>true</tt>, the
6812 <tt>llvm.memset</tt> call is a <a href="#volatile">volatile operation</a>.
6813 The detailed access behavior is not very cleanly specified and it is unwise
6814 to depend on it.</p>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6815
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6816<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6817<p>The '<tt>llvm.memset.*</tt>' intrinsics fill "len" bytes of memory starting
6818 at the destination location. If the argument is known to be aligned to some
6819 boundary, this can be specified as the fourth argument, otherwise it should
6820 be set to 0 or 1.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6821
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6822</div>
6823
Chris Lattner3b4f4372004-06-11 02:28:03 +0000[diff] [blame]6824<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6825<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6826 <a name="int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6827</h4>
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]6828
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6829<div>
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]6830
6831<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6832<p>This is an overloaded intrinsic. You can use <tt>llvm.sqrt</tt> on any
6833 floating point or vector of floating point type. Not all targets support all
6834 types however.</p>
6835
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]6836<pre>
Dale Johannesendd89d272007-10-02 17:47:38 +0000[diff] [blame]6837 declare float @llvm.sqrt.f32(float %Val)
6838 declare double @llvm.sqrt.f64(double %Val)
6839 declare x86_fp80 @llvm.sqrt.f80(x86_fp80 %Val)
6840 declare fp128 @llvm.sqrt.f128(fp128 %Val)
6841 declare ppc_fp128 @llvm.sqrt.ppcf128(ppc_fp128 %Val)
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]6842</pre>
6843
6844<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6845<p>The '<tt>llvm.sqrt</tt>' intrinsics return the sqrt of the specified operand,
6846 returning the same value as the libm '<tt>sqrt</tt>' functions would.
6847 Unlike <tt>sqrt</tt> in libm, however, <tt>llvm.sqrt</tt> has undefined
6848 behavior for negative numbers other than -0.0 (which allows for better
6849 optimization, because there is no need to worry about errno being
6850 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]6851
6852<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6853<p>The argument and return value are floating point numbers of the same
6854 type.</p>
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]6855
6856<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6857<p>This function returns the sqrt of the specified operand if it is a
6858 nonnegative floating point number.</p>
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]6859
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]6860</div>
6861
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]6862<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6863<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6864 <a name="int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6865</h4>
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]6866
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6867<div>
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]6868
6869<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6870<p>This is an overloaded intrinsic. You can use <tt>llvm.powi</tt> on any
6871 floating point or vector of floating point type. Not all targets support all
6872 types however.</p>
6873
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]6874<pre>
Dale Johannesendd89d272007-10-02 17:47:38 +0000[diff] [blame]6875 declare float @llvm.powi.f32(float %Val, i32 %power)
6876 declare double @llvm.powi.f64(double %Val, i32 %power)
6877 declare x86_fp80 @llvm.powi.f80(x86_fp80 %Val, i32 %power)
6878 declare fp128 @llvm.powi.f128(fp128 %Val, i32 %power)
6879 declare ppc_fp128 @llvm.powi.ppcf128(ppc_fp128 %Val, i32 %power)
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]6880</pre>
6881
6882<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6883<p>The '<tt>llvm.powi.*</tt>' intrinsics return the first operand raised to the
6884 specified (positive or negative) power. The order of evaluation of
6885 multiplications is not defined. When a vector of floating point type is
6886 used, the second argument remains a scalar integer value.</p>
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]6887
6888<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6889<p>The second argument is an integer power, and the first is a value to raise to
6890 that power.</p>
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]6891
6892<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6893<p>This function returns the first value raised to the second power with an
6894 unspecified sequence of rounding operations.</p>
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]6895
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]6896</div>
6897
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6898<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6899<h4>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6900 <a name="int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6901</h4>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6902
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6903<div>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6904
6905<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6906<p>This is an overloaded intrinsic. You can use <tt>llvm.sin</tt> on any
6907 floating point or vector of floating point type. Not all targets support all
6908 types however.</p>
6909
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6910<pre>
6911 declare float @llvm.sin.f32(float %Val)
6912 declare double @llvm.sin.f64(double %Val)
6913 declare x86_fp80 @llvm.sin.f80(x86_fp80 %Val)
6914 declare fp128 @llvm.sin.f128(fp128 %Val)
6915 declare ppc_fp128 @llvm.sin.ppcf128(ppc_fp128 %Val)
6916</pre>
6917
6918<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6919<p>The '<tt>llvm.sin.*</tt>' intrinsics return the sine of the operand.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6920
6921<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6922<p>The argument and return value are floating point numbers of the same
6923 type.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6924
6925<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6926<p>This function returns the sine of the specified operand, returning the same
6927 values as the libm <tt>sin</tt> functions would, and handles error conditions
6928 in the same way.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6929
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6930</div>
6931
6932<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6933<h4>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6934 <a name="int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6935</h4>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6936
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6937<div>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6938
6939<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6940<p>This is an overloaded intrinsic. You can use <tt>llvm.cos</tt> on any
6941 floating point or vector of floating point type. Not all targets support all
6942 types however.</p>
6943
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6944<pre>
6945 declare float @llvm.cos.f32(float %Val)
6946 declare double @llvm.cos.f64(double %Val)
6947 declare x86_fp80 @llvm.cos.f80(x86_fp80 %Val)
6948 declare fp128 @llvm.cos.f128(fp128 %Val)
6949 declare ppc_fp128 @llvm.cos.ppcf128(ppc_fp128 %Val)
6950</pre>
6951
6952<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6953<p>The '<tt>llvm.cos.*</tt>' intrinsics return the cosine of the operand.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6954
6955<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6956<p>The argument and return value are floating point numbers of the same
6957 type.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6958
6959<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6960<p>This function returns the cosine of the specified operand, returning the same
6961 values as the libm <tt>cos</tt> functions would, and handles error conditions
6962 in the same way.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6963
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6964</div>
6965
6966<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6967<h4>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6968 <a name="int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6969</h4>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6970
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6971<div>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6972
6973<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6974<p>This is an overloaded intrinsic. You can use <tt>llvm.pow</tt> on any
6975 floating point or vector of floating point type. Not all targets support all
6976 types however.</p>
6977
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6978<pre>
6979 declare float @llvm.pow.f32(float %Val, float %Power)
6980 declare double @llvm.pow.f64(double %Val, double %Power)
6981 declare x86_fp80 @llvm.pow.f80(x86_fp80 %Val, x86_fp80 %Power)
6982 declare fp128 @llvm.pow.f128(fp128 %Val, fp128 %Power)
6983 declare ppc_fp128 @llvm.pow.ppcf128(ppc_fp128 %Val, ppc_fp128 Power)
6984</pre>
6985
6986<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6987<p>The '<tt>llvm.pow.*</tt>' intrinsics return the first operand raised to the
6988 specified (positive or negative) power.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6989
6990<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6991<p>The second argument is a floating point power, and the first is a value to
6992 raise to that power.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6993
6994<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6995<p>This function returns the first value raised to the second power, returning
6996 the same values as the libm <tt>pow</tt> functions would, and handles error
6997 conditions in the same way.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6998
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6999</div>
7000
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7001</div>
7002
Dan Gohman911fa902011-05-23 21:13:03 +0000[diff] [blame]7003<!-- _______________________________________________________________________ -->
7004<h4>
7005 <a name="int_exp">'<tt>llvm.exp.*</tt>' Intrinsic</a>
7006</h4>
7007
7008<div>
7009
7010<h5>Syntax:</h5>
7011<p>This is an overloaded intrinsic. You can use <tt>llvm.exp</tt> on any
7012 floating point or vector of floating point type. Not all targets support all
7013 types however.</p>
7014
7015<pre>
7016 declare float @llvm.exp.f32(float %Val)
7017 declare double @llvm.exp.f64(double %Val)
7018 declare x86_fp80 @llvm.exp.f80(x86_fp80 %Val)
7019 declare fp128 @llvm.exp.f128(fp128 %Val)
7020 declare ppc_fp128 @llvm.exp.ppcf128(ppc_fp128 %Val)
7021</pre>
7022
7023<h5>Overview:</h5>
7024<p>The '<tt>llvm.exp.*</tt>' intrinsics perform the exp function.</p>
7025
7026<h5>Arguments:</h5>
7027<p>The argument and return value are floating point numbers of the same
7028 type.</p>
7029
7030<h5>Semantics:</h5>
7031<p>This function returns the same values as the libm <tt>exp</tt> functions
7032 would, and handles error conditions in the same way.</p>
7033
7034</div>
7035
7036<!-- _______________________________________________________________________ -->
7037<h4>
7038 <a name="int_log">'<tt>llvm.log.*</tt>' Intrinsic</a>
7039</h4>
7040
7041<div>
7042
7043<h5>Syntax:</h5>
7044<p>This is an overloaded intrinsic. You can use <tt>llvm.log</tt> on any
7045 floating point or vector of floating point type. Not all targets support all
7046 types however.</p>
7047
7048<pre>
7049 declare float @llvm.log.f32(float %Val)
7050 declare double @llvm.log.f64(double %Val)
7051 declare x86_fp80 @llvm.log.f80(x86_fp80 %Val)
7052 declare fp128 @llvm.log.f128(fp128 %Val)
7053 declare ppc_fp128 @llvm.log.ppcf128(ppc_fp128 %Val)
7054</pre>
7055
7056<h5>Overview:</h5>
7057<p>The '<tt>llvm.log.*</tt>' intrinsics perform the log function.</p>
7058
7059<h5>Arguments:</h5>
7060<p>The argument and return value are floating point numbers of the same
7061 type.</p>
7062
7063<h5>Semantics:</h5>
7064<p>This function returns the same values as the libm <tt>log</tt> functions
7065 would, and handles error conditions in the same way.</p>
7066
Cameron Zwarichf03fa182011-07-08 21:39:21 +0000[diff] [blame]7067<h4>
7068 <a name="int_fma">'<tt>llvm.fma.*</tt>' Intrinsic</a>
7069</h4>
7070
7071<div>
7072
7073<h5>Syntax:</h5>
7074<p>This is an overloaded intrinsic. You can use <tt>llvm.fma</tt> on any
7075 floating point or vector of floating point type. Not all targets support all
7076 types however.</p>
7077
7078<pre>
7079 declare float @llvm.fma.f32(float %a, float %b, float %c)
7080 declare double @llvm.fma.f64(double %a, double %b, double %c)
7081 declare x86_fp80 @llvm.fma.f80(x86_fp80 %a, x86_fp80 %b, x86_fp80 %c)
7082 declare fp128 @llvm.fma.f128(fp128 %a, fp128 %b, fp128 %c)
7083 declare ppc_fp128 @llvm.fma.ppcf128(ppc_fp128 %a, ppc_fp128 %b, ppc_fp128 %c)
7084</pre>
7085
7086<h5>Overview:</h5>
Cameron Zwaricha32fd212011-07-08 22:13:55 +0000[diff] [blame]7087<p>The '<tt>llvm.fma.*</tt>' intrinsics perform the fused multiply-add
Cameron Zwarichf03fa182011-07-08 21:39:21 +0000[diff] [blame]7088 operation.</p>
7089
7090<h5>Arguments:</h5>
7091<p>The argument and return value are floating point numbers of the same
7092 type.</p>
7093
7094<h5>Semantics:</h5>
7095<p>This function returns the same values as the libm <tt>fma</tt> functions
7096 would.</p>
7097
Dan Gohman911fa902011-05-23 21:13:03 +0000[diff] [blame]7098</div>
7099
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7100<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7101<h3>
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]7102 <a name="int_manip">Bit Manipulation Intrinsics</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7103</h3>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7104
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7105<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7106
7107<p>LLVM provides intrinsics for a few important bit manipulation operations.
7108 These allow efficient code generation for some algorithms.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7109
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7110<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7111<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]7112 <a name="int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7113</h4>
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]7114
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7115<div>
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]7116
7117<h5>Syntax:</h5>
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]7118<p>This is an overloaded intrinsic function. You can use bswap on any integer
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7119 type that is an even number of bytes (i.e. BitWidth % 16 == 0).</p>
7120
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]7121<pre>
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]7122 declare i16 @llvm.bswap.i16(i16 &lt;id&gt;)
7123 declare i32 @llvm.bswap.i32(i32 &lt;id&gt;)
7124 declare i64 @llvm.bswap.i64(i64 &lt;id&gt;)
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]7125</pre>
7126
7127<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7128<p>The '<tt>llvm.bswap</tt>' family of intrinsics is used to byte swap integer
7129 values with an even number of bytes (positive multiple of 16 bits). These
7130 are useful for performing operations on data that is not in the target's
7131 native byte order.</p>
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]7132
7133<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7134<p>The <tt>llvm.bswap.i16</tt> intrinsic returns an i16 value that has the high
7135 and low byte of the input i16 swapped. Similarly,
7136 the <tt>llvm.bswap.i32</tt> intrinsic returns an i32 value that has the four
7137 bytes of the input i32 swapped, so that if the input bytes are numbered 0, 1,
7138 2, 3 then the returned i32 will have its bytes in 3, 2, 1, 0 order.
7139 The <tt>llvm.bswap.i48</tt>, <tt>llvm.bswap.i64</tt> and other intrinsics
7140 extend this concept to additional even-byte lengths (6 bytes, 8 bytes and
7141 more, respectively).</p>
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]7142
7143</div>
7144
7145<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7146<h4>
Reid Spencerb4f9a6f2006-01-16 21:12:35 +0000[diff] [blame]7147 <a name="int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7148</h4>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7149
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7150<div>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7151
7152<h5>Syntax:</h5>
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]7153<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]7154 width, or on any vector with integer elements. Not all targets support all
7155 bit widths or vector types, however.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7156
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7157<pre>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7158 declare i8 @llvm.ctpop.i8(i8 &lt;src&gt;)
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]7159 declare i16 @llvm.ctpop.i16(i16 &lt;src&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]7160 declare i32 @llvm.ctpop.i32(i32 &lt;src&gt;)
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]7161 declare i64 @llvm.ctpop.i64(i64 &lt;src&gt;)
7162 declare i256 @llvm.ctpop.i256(i256 &lt;src&gt;)
Owen Anderson2f37bdc2011-07-01 21:52:38 +0000[diff] [blame]7163 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]7164</pre>
7165
7166<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7167<p>The '<tt>llvm.ctpop</tt>' family of intrinsics counts the number of bits set
7168 in a value.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7169
7170<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7171<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]7172 integer type, or a vector with integer elements.
7173 The return type must match the argument type.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7174
7175<h5>Semantics:</h5>
Owen Anderson2f37bdc2011-07-01 21:52:38 +0000[diff] [blame]7176<p>The '<tt>llvm.ctpop</tt>' intrinsic counts the 1's in a variable, or within each
7177 element of a vector.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7178
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7179</div>
7180
7181<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7182<h4>
Chris Lattnerb748c672006-01-16 22:34:14 +0000[diff] [blame]7183 <a name="int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7184</h4>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7185
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7186<div>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7187
7188<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7189<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]7190 integer bit width, or any vector whose elements are integers. Not all
7191 targets support all bit widths or vector types, however.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7192
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7193<pre>
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]7194 declare i8 @llvm.ctlz.i8 (i8 &lt;src&gt;)
7195 declare i16 @llvm.ctlz.i16(i16 &lt;src&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]7196 declare i32 @llvm.ctlz.i32(i32 &lt;src&gt;)
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]7197 declare i64 @llvm.ctlz.i64(i64 &lt;src&gt;)
7198 declare i256 @llvm.ctlz.i256(i256 &lt;src&gt;)
Owen Anderson2f37bdc2011-07-01 21:52:38 +0000[diff] [blame]7199 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]7200</pre>
7201
7202<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7203<p>The '<tt>llvm.ctlz</tt>' family of intrinsic functions counts the number of
7204 leading zeros in a variable.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7205
7206<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7207<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]7208 integer type, or any vector type with integer element type.
7209 The return type must match the argument type.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7210
7211<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7212<p>The '<tt>llvm.ctlz</tt>' intrinsic counts the leading (most significant)
Owen Anderson2f37bdc2011-07-01 21:52:38 +0000[diff] [blame]7213 zeros in a variable, or within each element of the vector if the operation
7214 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]7215 the type of src. For example, <tt>llvm.ctlz(i32 2) = 30</tt>.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7216
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7217</div>
Chris Lattner3b4f4372004-06-11 02:28:03 +0000[diff] [blame]7218
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]7219<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7220<h4>
Chris Lattnerb748c672006-01-16 22:34:14 +0000[diff] [blame]7221 <a name="int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7222</h4>
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]7223
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7224<div>
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]7225
7226<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7227<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]7228 integer bit width, or any vector of integer elements. Not all targets
7229 support all bit widths or vector types, however.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7230
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]7231<pre>
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]7232 declare i8 @llvm.cttz.i8 (i8 &lt;src&gt;)
7233 declare i16 @llvm.cttz.i16(i16 &lt;src&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]7234 declare i32 @llvm.cttz.i32(i32 &lt;src&gt;)
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]7235 declare i64 @llvm.cttz.i64(i64 &lt;src&gt;)
7236 declare i256 @llvm.cttz.i256(i256 &lt;src&gt;)
Owen Anderson2f37bdc2011-07-01 21:52:38 +0000[diff] [blame]7237 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]7238</pre>
7239
7240<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7241<p>The '<tt>llvm.cttz</tt>' family of intrinsic functions counts the number of
7242 trailing zeros.</p>
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]7243
7244<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7245<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]7246 integer type, or a vectory with integer element type.. The return type
7247 must match the argument type.</p>
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]7248
7249<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7250<p>The '<tt>llvm.cttz</tt>' intrinsic counts the trailing (least significant)
Owen Anderson2f37bdc2011-07-01 21:52:38 +0000[diff] [blame]7251 zeros in a variable, or within each element of a vector.
7252 If the src == 0 then the result is the size in bits of
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7253 the type of src. For example, <tt>llvm.cttz(2) = 1</tt>.</p>
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]7254
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]7255</div>
7256
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7257</div>
7258
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]7259<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7260<h3>
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]7261 <a name="int_overflow">Arithmetic with Overflow Intrinsics</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7262</h3>
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]7263
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7264<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7265
7266<p>LLVM provides intrinsics for some arithmetic with overflow operations.</p>
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]7267
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7268<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7269<h4>
7270 <a name="int_sadd_overflow">
7271 '<tt>llvm.sadd.with.overflow.*</tt>' Intrinsics
7272 </a>
7273</h4>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7274
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7275<div>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7276
7277<h5>Syntax:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7278<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]7279 on any integer bit width.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7280
7281<pre>
7282 declare {i16, i1} @llvm.sadd.with.overflow.i16(i16 %a, i16 %b)
7283 declare {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
7284 declare {i64, i1} @llvm.sadd.with.overflow.i64(i64 %a, i64 %b)
7285</pre>
7286
7287<h5>Overview:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7288<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7289 a signed addition of the two arguments, and indicate whether an overflow
7290 occurred during the signed summation.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7291
7292<h5>Arguments:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7293<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]7294 be of integer types of any bit width, but they must have the same bit
7295 width. The second element of the result structure must be of
7296 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
7297 undergo signed addition.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7298
7299<h5>Semantics:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7300<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7301 a signed addition of the two variables. They return a structure &mdash; the
7302 first element of which is the signed summation, and the second element of
7303 which is a bit specifying if the signed summation resulted in an
7304 overflow.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7305
7306<h5>Examples:</h5>
7307<pre>
7308 %res = call {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
7309 %sum = extractvalue {i32, i1} %res, 0
7310 %obit = extractvalue {i32, i1} %res, 1
7311 br i1 %obit, label %overflow, label %normal
7312</pre>
7313
7314</div>
7315
7316<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7317<h4>
7318 <a name="int_uadd_overflow">
7319 '<tt>llvm.uadd.with.overflow.*</tt>' Intrinsics
7320 </a>
7321</h4>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7322
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7323<div>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7324
7325<h5>Syntax:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7326<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]7327 on any integer bit width.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7328
7329<pre>
7330 declare {i16, i1} @llvm.uadd.with.overflow.i16(i16 %a, i16 %b)
7331 declare {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
7332 declare {i64, i1} @llvm.uadd.with.overflow.i64(i64 %a, i64 %b)
7333</pre>
7334
7335<h5>Overview:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7336<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7337 an unsigned addition of the two arguments, and indicate whether a carry
7338 occurred during the unsigned summation.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7339
7340<h5>Arguments:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7341<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]7342 be of integer types of any bit width, but they must have the same bit
7343 width. The second element of the result structure must be of
7344 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
7345 undergo unsigned addition.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7346
7347<h5>Semantics:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7348<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7349 an unsigned addition of the two arguments. They return a structure &mdash;
7350 the first element of which is the sum, and the second element of which is a
7351 bit specifying if the unsigned summation resulted in a carry.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7352
7353<h5>Examples:</h5>
7354<pre>
7355 %res = call {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
7356 %sum = extractvalue {i32, i1} %res, 0
7357 %obit = extractvalue {i32, i1} %res, 1
7358 br i1 %obit, label %carry, label %normal
7359</pre>
7360
7361</div>
7362
7363<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7364<h4>
7365 <a name="int_ssub_overflow">
7366 '<tt>llvm.ssub.with.overflow.*</tt>' Intrinsics
7367 </a>
7368</h4>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7369
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7370<div>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7371
7372<h5>Syntax:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7373<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]7374 on any integer bit width.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7375
7376<pre>
7377 declare {i16, i1} @llvm.ssub.with.overflow.i16(i16 %a, i16 %b)
7378 declare {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
7379 declare {i64, i1} @llvm.ssub.with.overflow.i64(i64 %a, i64 %b)
7380</pre>
7381
7382<h5>Overview:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7383<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7384 a signed subtraction of the two arguments, and indicate whether an overflow
7385 occurred during the signed subtraction.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7386
7387<h5>Arguments:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7388<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]7389 be of integer types of any bit width, but they must have the same bit
7390 width. The second element of the result structure must be of
7391 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
7392 undergo signed subtraction.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7393
7394<h5>Semantics:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7395<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7396 a signed subtraction of the two arguments. They return a structure &mdash;
7397 the first element of which is the subtraction, and the second element of
7398 which is a bit specifying if the signed subtraction resulted in an
7399 overflow.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7400
7401<h5>Examples:</h5>
7402<pre>
7403 %res = call {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
7404 %sum = extractvalue {i32, i1} %res, 0
7405 %obit = extractvalue {i32, i1} %res, 1
7406 br i1 %obit, label %overflow, label %normal
7407</pre>
7408
7409</div>
7410
7411<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7412<h4>
7413 <a name="int_usub_overflow">
7414 '<tt>llvm.usub.with.overflow.*</tt>' Intrinsics
7415 </a>
7416</h4>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7417
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7418<div>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7419
7420<h5>Syntax:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7421<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]7422 on any integer bit width.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7423
7424<pre>
7425 declare {i16, i1} @llvm.usub.with.overflow.i16(i16 %a, i16 %b)
7426 declare {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
7427 declare {i64, i1} @llvm.usub.with.overflow.i64(i64 %a, i64 %b)
7428</pre>
7429
7430<h5>Overview:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7431<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7432 an unsigned subtraction of the two arguments, and indicate whether an
7433 overflow occurred during the unsigned subtraction.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7434
7435<h5>Arguments:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7436<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]7437 be of integer types of any bit width, but they must have the same bit
7438 width. The second element of the result structure must be of
7439 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
7440 undergo unsigned subtraction.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7441
7442<h5>Semantics:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7443<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7444 an unsigned subtraction of the two arguments. They return a structure &mdash;
7445 the first element of which is the subtraction, and the second element of
7446 which is a bit specifying if the unsigned subtraction resulted in an
7447 overflow.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7448
7449<h5>Examples:</h5>
7450<pre>
7451 %res = call {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
7452 %sum = extractvalue {i32, i1} %res, 0
7453 %obit = extractvalue {i32, i1} %res, 1
7454 br i1 %obit, label %overflow, label %normal
7455</pre>
7456
7457</div>
7458
7459<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7460<h4>
7461 <a name="int_smul_overflow">
7462 '<tt>llvm.smul.with.overflow.*</tt>' Intrinsics
7463 </a>
7464</h4>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7465
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7466<div>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7467
7468<h5>Syntax:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7469<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]7470 on any integer bit width.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7471
7472<pre>
7473 declare {i16, i1} @llvm.smul.with.overflow.i16(i16 %a, i16 %b)
7474 declare {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
7475 declare {i64, i1} @llvm.smul.with.overflow.i64(i64 %a, i64 %b)
7476</pre>
7477
7478<h5>Overview:</h5>
7479
7480<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7481 a signed multiplication of the two arguments, and indicate whether an
7482 overflow occurred during the signed multiplication.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7483
7484<h5>Arguments:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7485<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]7486 be of integer types of any bit width, but they must have the same bit
7487 width. The second element of the result structure must be of
7488 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
7489 undergo signed multiplication.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7490
7491<h5>Semantics:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7492<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7493 a signed multiplication of the two arguments. They return a structure &mdash;
7494 the first element of which is the multiplication, and the second element of
7495 which is a bit specifying if the signed multiplication resulted in an
7496 overflow.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7497
7498<h5>Examples:</h5>
7499<pre>
7500 %res = call {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
7501 %sum = extractvalue {i32, i1} %res, 0
7502 %obit = extractvalue {i32, i1} %res, 1
7503 br i1 %obit, label %overflow, label %normal
7504</pre>
7505
Reid Spencer5bf54c82007-04-11 23:23:49 +0000[diff] [blame]7506</div>
7507
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]7508<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7509<h4>
7510 <a name="int_umul_overflow">
7511 '<tt>llvm.umul.with.overflow.*</tt>' Intrinsics
7512 </a>
7513</h4>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]7514
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7515<div>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]7516
7517<h5>Syntax:</h5>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]7518<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]7519 on any integer bit width.</p>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]7520
7521<pre>
7522 declare {i16, i1} @llvm.umul.with.overflow.i16(i16 %a, i16 %b)
7523 declare {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
7524 declare {i64, i1} @llvm.umul.with.overflow.i64(i64 %a, i64 %b)
7525</pre>
7526
7527<h5>Overview:</h5>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]7528<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7529 a unsigned multiplication of the two arguments, and indicate whether an
7530 overflow occurred during the unsigned multiplication.</p>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]7531
7532<h5>Arguments:</h5>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]7533<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]7534 be of integer types of any bit width, but they must have the same bit
7535 width. The second element of the result structure must be of
7536 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
7537 undergo unsigned multiplication.</p>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]7538
7539<h5>Semantics:</h5>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]7540<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7541 an unsigned multiplication of the two arguments. They return a structure
7542 &mdash; the first element of which is the multiplication, and the second
7543 element of which is a bit specifying if the unsigned multiplication resulted
7544 in an overflow.</p>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]7545
7546<h5>Examples:</h5>
7547<pre>
7548 %res = call {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
7549 %sum = extractvalue {i32, i1} %res, 0
7550 %obit = extractvalue {i32, i1} %res, 1
7551 br i1 %obit, label %overflow, label %normal
7552</pre>
7553
7554</div>
7555
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7556</div>
7557
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]7558<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7559<h3>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]7560 <a name="int_fp16">Half Precision Floating Point Intrinsics</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7561</h3>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]7562
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7563<div>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]7564
Chris Lattner022a9fb2010-03-15 04:12:21 +0000[diff] [blame]7565<p>Half precision floating point is a storage-only format. This means that it is
7566 a dense encoding (in memory) but does not support computation in the
7567 format.</p>
Chris Lattnerbbd8bd32010-03-14 23:03:31 +0000[diff] [blame]7568
Chris Lattner022a9fb2010-03-15 04:12:21 +0000[diff] [blame]7569<p>This means that code must first load the half-precision floating point
Chris Lattnerbbd8bd32010-03-14 23:03:31 +0000[diff] [blame]7570 value as an i16, then convert it to float with <a
7571 href="#int_convert_from_fp16"><tt>llvm.convert.from.fp16</tt></a>.
7572 Computation can then be performed on the float value (including extending to
Chris Lattner022a9fb2010-03-15 04:12:21 +0000[diff] [blame]7573 double etc). To store the value back to memory, it is first converted to
7574 float if needed, then converted to i16 with
Chris Lattnerbbd8bd32010-03-14 23:03:31 +0000[diff] [blame]7575 <a href="#int_convert_to_fp16"><tt>llvm.convert.to.fp16</tt></a>, then
7576 storing as an i16 value.</p>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]7577
7578<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7579<h4>
7580 <a name="int_convert_to_fp16">
7581 '<tt>llvm.convert.to.fp16</tt>' Intrinsic
7582 </a>
7583</h4>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]7584
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7585<div>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]7586
7587<h5>Syntax:</h5>
7588<pre>
7589 declare i16 @llvm.convert.to.fp16(f32 %a)
7590</pre>
7591
7592<h5>Overview:</h5>
7593<p>The '<tt>llvm.convert.to.fp16</tt>' intrinsic function performs
7594 a conversion from single precision floating point format to half precision
7595 floating point format.</p>
7596
7597<h5>Arguments:</h5>
7598<p>The intrinsic function contains single argument - the value to be
7599 converted.</p>
7600
7601<h5>Semantics:</h5>
7602<p>The '<tt>llvm.convert.to.fp16</tt>' intrinsic function performs
7603 a conversion from single precision floating point format to half precision
Chris Lattner022a9fb2010-03-15 04:12:21 +0000[diff] [blame]7604 floating point format. The return value is an <tt>i16</tt> which
Chris Lattnerbbd8bd32010-03-14 23:03:31 +0000[diff] [blame]7605 contains the converted number.</p>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]7606
7607<h5>Examples:</h5>
7608<pre>
7609 %res = call i16 @llvm.convert.to.fp16(f32 %a)
7610 store i16 %res, i16* @x, align 2
7611</pre>
7612
7613</div>
7614
7615<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7616<h4>
7617 <a name="int_convert_from_fp16">
7618 '<tt>llvm.convert.from.fp16</tt>' Intrinsic
7619 </a>
7620</h4>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]7621
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7622<div>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]7623
7624<h5>Syntax:</h5>
7625<pre>
7626 declare f32 @llvm.convert.from.fp16(i16 %a)
7627</pre>
7628
7629<h5>Overview:</h5>
7630<p>The '<tt>llvm.convert.from.fp16</tt>' intrinsic function performs
7631 a conversion from half precision floating point format to single precision
7632 floating point format.</p>
7633
7634<h5>Arguments:</h5>
7635<p>The intrinsic function contains single argument - the value to be
7636 converted.</p>
7637
7638<h5>Semantics:</h5>
7639<p>The '<tt>llvm.convert.from.fp16</tt>' intrinsic function performs a
Chris Lattner022a9fb2010-03-15 04:12:21 +0000[diff] [blame]7640 conversion from half single precision floating point format to single
Chris Lattnerbbd8bd32010-03-14 23:03:31 +0000[diff] [blame]7641 precision floating point format. The input half-float value is represented by
7642 an <tt>i16</tt> value.</p>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]7643
7644<h5>Examples:</h5>
7645<pre>
7646 %a = load i16* @x, align 2
7647 %res = call f32 @llvm.convert.from.fp16(i16 %a)
7648</pre>
7649
7650</div>
7651
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7652</div>
7653
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]7654<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7655<h3>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]7656 <a name="int_debugger">Debugger Intrinsics</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7657</h3>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]7658
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7659<div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]7660
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7661<p>The LLVM debugger intrinsics (which all start with <tt>llvm.dbg.</tt>
7662 prefix), are described in
7663 the <a href="SourceLevelDebugging.html#format_common_intrinsics">LLVM Source
7664 Level Debugging</a> document.</p>
7665
7666</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]7667
Jim Laskey2211f492007-03-14 19:31:19 +0000[diff] [blame]7668<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7669<h3>
Jim Laskey2211f492007-03-14 19:31:19 +0000[diff] [blame]7670 <a name="int_eh">Exception Handling Intrinsics</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7671</h3>
Jim Laskey2211f492007-03-14 19:31:19 +0000[diff] [blame]7672
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7673<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7674
7675<p>The LLVM exception handling intrinsics (which all start with
7676 <tt>llvm.eh.</tt> prefix), are described in
7677 the <a href="ExceptionHandling.html#format_common_intrinsics">LLVM Exception
7678 Handling</a> document.</p>
7679
Jim Laskey2211f492007-03-14 19:31:19 +0000[diff] [blame]7680</div>
7681
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]7682<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7683<h3>
Duncan Sandsa0984362011-09-06 13:37:06 +0000[diff] [blame]7684 <a name="int_trampoline">Trampoline Intrinsics</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7685</h3>
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]7686
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7687<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7688
Duncan Sandsa0984362011-09-06 13:37:06 +0000[diff] [blame]7689<p>These intrinsics make it possible to excise one parameter, marked with
Dan Gohman3770af52010-07-02 23:18:08 +0000[diff] [blame]7690 the <a href="#nest"><tt>nest</tt></a> attribute, from a function.
7691 The result is a callable
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7692 function pointer lacking the nest parameter - the caller does not need to
7693 provide a value for it. Instead, the value to use is stored in advance in a
7694 "trampoline", a block of memory usually allocated on the stack, which also
7695 contains code to splice the nest value into the argument list. This is used
7696 to implement the GCC nested function address extension.</p>
7697
7698<p>For example, if the function is
7699 <tt>i32 f(i8* nest %c, i32 %x, i32 %y)</tt> then the resulting function
7700 pointer has signature <tt>i32 (i32, i32)*</tt>. It can be created as
7701 follows:</p>
7702
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]7703<pre class="doc_code">
Duncan Sands86e01192007-09-11 14:10:23 +0000[diff] [blame]7704 %tramp = alloca [10 x i8], align 4 ; size and alignment only correct for X86
7705 %tramp1 = getelementptr [10 x i8]* %tramp, i32 0, i32 0
Duncan Sandsa0984362011-09-06 13:37:06 +0000[diff] [blame]7706 call i8* @llvm.init.trampoline(i8* %tramp1, i8* bitcast (i32 (i8*, i32, i32)* @f to i8*), i8* %nval)
7707 %p = call i8* @llvm.adjust.trampoline(i8* %tramp1)
Duncan Sands86e01192007-09-11 14:10:23 +0000[diff] [blame]7708 %fp = bitcast i8* %p to i32 (i32, i32)*
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]7709</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7710
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7711<p>The call <tt>%val = call i32 %fp(i32 %x, i32 %y)</tt> is then equivalent
7712 to <tt>%val = call i32 %f(i8* %nval, i32 %x, i32 %y)</tt>.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7713
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]7714<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7715<h4>
7716 <a name="int_it">
7717 '<tt>llvm.init.trampoline</tt>' Intrinsic
7718 </a>
7719</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7720
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7721<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7722
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]7723<h5>Syntax:</h5>
7724<pre>
Duncan Sandsa0984362011-09-06 13:37:06 +0000[diff] [blame]7725 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]7726</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7727
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]7728<h5>Overview:</h5>
Duncan Sandsa0984362011-09-06 13:37:06 +0000[diff] [blame]7729<p>This fills the memory pointed to by <tt>tramp</tt> with executable code,
7730 turning it into a trampoline.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7731
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]7732<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7733<p>The <tt>llvm.init.trampoline</tt> intrinsic takes three arguments, all
7734 pointers. The <tt>tramp</tt> argument must point to a sufficiently large and
7735 sufficiently aligned block of memory; this memory is written to by the
7736 intrinsic. Note that the size and the alignment are target-specific - LLVM
7737 currently provides no portable way of determining them, so a front-end that
7738 generates this intrinsic needs to have some target-specific knowledge.
7739 The <tt>func</tt> argument must hold a function bitcast to
7740 an <tt>i8*</tt>.</p>
7741
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]7742<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7743<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]7744 dependent code, turning it into a function. Then <tt>tramp</tt> needs to be
7745 passed to <a href="#int_at">llvm.adjust.trampoline</a> to get a pointer
7746 which can be <a href="#int_trampoline">bitcast (to a new function) and
7747 called</a>. The new function's signature is the same as that of
7748 <tt>func</tt> with any arguments marked with the <tt>nest</tt> attribute
7749 removed. At most one such <tt>nest</tt> argument is allowed, and it must be of
7750 pointer type. Calling the new function is equivalent to calling <tt>func</tt>
7751 with the same argument list, but with <tt>nval</tt> used for the missing
7752 <tt>nest</tt> argument. If, after calling <tt>llvm.init.trampoline</tt>, the
7753 memory pointed to by <tt>tramp</tt> is modified, then the effect of any later call
7754 to the returned function pointer is undefined.</p>
7755</div>
7756
7757<!-- _______________________________________________________________________ -->
7758<h4>
7759 <a name="int_at">
7760 '<tt>llvm.adjust.trampoline</tt>' Intrinsic
7761 </a>
7762</h4>
7763
7764<div>
7765
7766<h5>Syntax:</h5>
7767<pre>
7768 declare i8* @llvm.adjust.trampoline(i8* &lt;tramp&gt;)
7769</pre>
7770
7771<h5>Overview:</h5>
7772<p>This performs any required machine-specific adjustment to the address of a
7773 trampoline (passed as <tt>tramp</tt>).</p>
7774
7775<h5>Arguments:</h5>
7776<p><tt>tramp</tt> must point to a block of memory which already has trampoline code
7777 filled in by a previous call to <a href="#int_it"><tt>llvm.init.trampoline</tt>
7778 </a>.</p>
7779
7780<h5>Semantics:</h5>
7781<p>On some architectures the address of the code to be executed needs to be
7782 different to the address where the trampoline is actually stored. This
7783 intrinsic returns the executable address corresponding to <tt>tramp</tt>
7784 after performing the required machine specific adjustments.
7785 The pointer returned can then be <a href="#int_trampoline"> bitcast and
7786 executed</a>.
7787</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7788
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]7789</div>
7790
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7791</div>
7792
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]7793<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7794<h3>
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7795 <a name="int_atomics">Atomic Operations and Synchronization Intrinsics</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7796</h3>
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7797
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7798<div>
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7799
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7800<p>These intrinsic functions expand the "universal IR" of LLVM to represent
7801 hardware constructs for atomic operations and memory synchronization. This
7802 provides an interface to the hardware, not an interface to the programmer. It
7803 is aimed at a low enough level to allow any programming models or APIs
7804 (Application Programming Interfaces) which need atomic behaviors to map
7805 cleanly onto it. It is also modeled primarily on hardware behavior. Just as
7806 hardware provides a "universal IR" for source languages, it also provides a
7807 starting point for developing a "universal" atomic operation and
7808 synchronization IR.</p>
7809
7810<p>These do <em>not</em> form an API such as high-level threading libraries,
7811 software transaction memory systems, atomic primitives, and intrinsic
7812 functions as found in BSD, GNU libc, atomic_ops, APR, and other system and
7813 application libraries. The hardware interface provided by LLVM should allow
7814 a clean implementation of all of these APIs and parallel programming models.
7815 No one model or paradigm should be selected above others unless the hardware
7816 itself ubiquitously does so.</p>
7817
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7818<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7819<h4>
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7820 <a name="int_memory_barrier">'<tt>llvm.memory.barrier</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7821</h4>
7822
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7823<div>
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7824<h5>Syntax:</h5>
7825<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7826 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]7827</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7828
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7829<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7830<p>The <tt>llvm.memory.barrier</tt> intrinsic guarantees ordering between
7831 specific pairs of memory access types.</p>
7832
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7833<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7834<p>The <tt>llvm.memory.barrier</tt> intrinsic requires five boolean arguments.
7835 The first four arguments enables a specific barrier as listed below. The
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]7836 fifth argument specifies that the barrier applies to io or device or uncached
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7837 memory.</p>
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7838
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7839<ul>
7840 <li><tt>ll</tt>: load-load barrier</li>
7841 <li><tt>ls</tt>: load-store barrier</li>
7842 <li><tt>sl</tt>: store-load barrier</li>
7843 <li><tt>ss</tt>: store-store barrier</li>
7844 <li><tt>device</tt>: barrier applies to device and uncached memory also.</li>
7845</ul>
7846
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7847<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7848<p>This intrinsic causes the system to enforce some ordering constraints upon
7849 the loads and stores of the program. This barrier does not
7850 indicate <em>when</em> any events will occur, it only enforces
7851 an <em>order</em> in which they occur. For any of the specified pairs of load
7852 and store operations (f.ex. load-load, or store-load), all of the first
7853 operations preceding the barrier will complete before any of the second
7854 operations succeeding the barrier begin. Specifically the semantics for each
7855 pairing is as follows:</p>
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7856
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7857<ul>
7858 <li><tt>ll</tt>: All loads before the barrier must complete before any load
7859 after the barrier begins.</li>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]7860 <li><tt>ls</tt>: All loads before the barrier must complete before any
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7861 store after the barrier begins.</li>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]7862 <li><tt>ss</tt>: All stores before the barrier must complete before any
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7863 store after the barrier begins.</li>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]7864 <li><tt>sl</tt>: All stores before the barrier must complete before any
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7865 load after the barrier begins.</li>
7866</ul>
7867
7868<p>These semantics are applied with a logical "and" behavior when more than one
7869 is enabled in a single memory barrier intrinsic.</p>
7870
7871<p>Backends may implement stronger barriers than those requested when they do
7872 not support as fine grained a barrier as requested. Some architectures do
7873 not need all types of barriers and on such architectures, these become
7874 noops.</p>
7875
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7876<h5>Example:</h5>
7877<pre>
Victor Hernandeza70c6df2009-10-26 23:44:29 +0000[diff] [blame]7878%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7879%ptr = bitcast i8* %mallocP to i32*
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7880 store i32 4, %ptr
7881
7882%result1 = load i32* %ptr <i>; yields {i32}:result1 = 4</i>
Evan Cheng0ac49c62011-06-29 17:14:00 +0000[diff] [blame]7883 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]7884 <i>; guarantee the above finishes</i>
7885 store i32 8, %ptr <i>; before this begins</i>
7886</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7887
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7888</div>
7889
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7890<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7891<h4>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7892 <a name="int_atomic_cmp_swap">'<tt>llvm.atomic.cmp.swap.*</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7893</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7894
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7895<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7896
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7897<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7898<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.cmp.swap</tt> on
7899 any integer bit width and for different address spaces. Not all targets
7900 support all bit widths however.</p>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7901
7902<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7903 declare i8 @llvm.atomic.cmp.swap.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;cmp&gt;, i8 &lt;val&gt;)
7904 declare i16 @llvm.atomic.cmp.swap.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;cmp&gt;, i16 &lt;val&gt;)
7905 declare i32 @llvm.atomic.cmp.swap.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;cmp&gt;, i32 &lt;val&gt;)
7906 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]7907</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7908
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7909<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7910<p>This loads a value in memory and compares it to a given value. If they are
7911 equal, it stores a new value into the memory.</p>
7912
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7913<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7914<p>The <tt>llvm.atomic.cmp.swap</tt> intrinsic takes three arguments. The result
7915 as well as both <tt>cmp</tt> and <tt>val</tt> must be integer values with the
7916 same bit width. The <tt>ptr</tt> argument must be a pointer to a value of
7917 this integer type. While any bit width integer may be used, targets may only
7918 lower representations they support in hardware.</p>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7919
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7920<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7921<p>This entire intrinsic must be executed atomically. It first loads the value
7922 in memory pointed to by <tt>ptr</tt> and compares it with the
7923 value <tt>cmp</tt>. If they are equal, <tt>val</tt> is stored into the
7924 memory. The loaded value is yielded in all cases. This provides the
7925 equivalent of an atomic compare-and-swap operation within the SSA
7926 framework.</p>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7927
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7928<h5>Examples:</h5>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7929<pre>
Victor Hernandeza70c6df2009-10-26 23:44:29 +0000[diff] [blame]7930%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7931%ptr = bitcast i8* %mallocP to i32*
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7932 store i32 4, %ptr
7933
7934%val1 = add i32 4, 4
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7935%result1 = call i32 @llvm.atomic.cmp.swap.i32.p0i32(i32* %ptr, i32 4, %val1)
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7936 <i>; yields {i32}:result1 = 4</i>
7937%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
7938%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
7939
7940%val2 = add i32 1, 1
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7941%result2 = call i32 @llvm.atomic.cmp.swap.i32.p0i32(i32* %ptr, i32 5, %val2)
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7942 <i>; yields {i32}:result2 = 8</i>
7943%stored2 = icmp eq i32 %result2, 5 <i>; yields {i1}:stored2 = false</i>
7944
7945%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 8</i>
7946</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7947
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7948</div>
7949
7950<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7951<h4>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7952 <a name="int_atomic_swap">'<tt>llvm.atomic.swap.*</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7953</h4>
7954
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7955<div>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7956<h5>Syntax:</h5>
7957
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7958<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.swap</tt> on any
7959 integer bit width. Not all targets support all bit widths however.</p>
7960
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7961<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7962 declare i8 @llvm.atomic.swap.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;val&gt;)
7963 declare i16 @llvm.atomic.swap.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;val&gt;)
7964 declare i32 @llvm.atomic.swap.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;val&gt;)
7965 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]7966</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7967
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7968<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7969<p>This intrinsic loads the value stored in memory at <tt>ptr</tt> and yields
7970 the value from memory. It then stores the value in <tt>val</tt> in the memory
7971 at <tt>ptr</tt>.</p>
7972
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7973<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7974<p>The <tt>llvm.atomic.swap</tt> intrinsic takes two arguments. Both
7975 the <tt>val</tt> argument and the result must be integers of the same bit
7976 width. The first argument, <tt>ptr</tt>, must be a pointer to a value of this
7977 integer type. The targets may only lower integer representations they
7978 support.</p>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7979
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7980<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7981<p>This intrinsic loads the value pointed to by <tt>ptr</tt>, yields it, and
7982 stores <tt>val</tt> back into <tt>ptr</tt> atomically. This provides the
7983 equivalent of an atomic swap operation within the SSA framework.</p>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7984
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7985<h5>Examples:</h5>
7986<pre>
Victor Hernandeza70c6df2009-10-26 23:44:29 +0000[diff] [blame]7987%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7988%ptr = bitcast i8* %mallocP to i32*
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7989 store i32 4, %ptr
7990
7991%val1 = add i32 4, 4
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7992%result1 = call i32 @llvm.atomic.swap.i32.p0i32(i32* %ptr, i32 %val1)
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7993 <i>; yields {i32}:result1 = 4</i>
7994%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
7995%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
7996
7997%val2 = add i32 1, 1
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7998%result2 = call i32 @llvm.atomic.swap.i32.p0i32(i32* %ptr, i32 %val2)
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7999 <i>; yields {i32}:result2 = 8</i>
8000
8001%stored2 = icmp eq i32 %result2, 8 <i>; yields {i1}:stored2 = true</i>
8002%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 2</i>
8003</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8004
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]8005</div>
8006
8007<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8008<h4>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]8009 <a name="int_atomic_load_add">'<tt>llvm.atomic.load.add.*</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8010</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8011
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]8012<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8013
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]8014<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8015<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.load.add</tt> on
8016 any integer bit width. Not all targets support all bit widths however.</p>
8017
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]8018<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]8019 declare i8 @llvm.atomic.load.add.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
8020 declare i16 @llvm.atomic.load.add.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
8021 declare i32 @llvm.atomic.load.add.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
8022 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]8023</pre>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]8024
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8025<h5>Overview:</h5>
8026<p>This intrinsic adds <tt>delta</tt> to the value stored in memory
8027 at <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.</p>
8028
8029<h5>Arguments:</h5>
8030<p>The intrinsic takes two arguments, the first a pointer to an integer value
8031 and the second an integer value. The result is also an integer value. These
8032 integer types can have any bit width, but they must all have the same bit
8033 width. The targets may only lower integer representations they support.</p>
8034
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]8035<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8036<p>This intrinsic does a series of operations atomically. It first loads the
8037 value stored at <tt>ptr</tt>. It then adds <tt>delta</tt>, stores the result
8038 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]8039
8040<h5>Examples:</h5>
8041<pre>
Victor Hernandeza70c6df2009-10-26 23:44:29 +0000[diff] [blame]8042%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
8043%ptr = bitcast i8* %mallocP to i32*
8044 store i32 4, %ptr
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]8045%result1 = call i32 @llvm.atomic.load.add.i32.p0i32(i32* %ptr, i32 4)
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]8046 <i>; yields {i32}:result1 = 4</i>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]8047%result2 = call i32 @llvm.atomic.load.add.i32.p0i32(i32* %ptr, i32 2)
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]8048 <i>; yields {i32}:result2 = 8</i>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]8049%result3 = call i32 @llvm.atomic.load.add.i32.p0i32(i32* %ptr, i32 5)
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]8050 <i>; yields {i32}:result3 = 10</i>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]8051%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 15</i>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]8052</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8053
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]8054</div>
8055
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]8056<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8057<h4>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]8058 <a name="int_atomic_load_sub">'<tt>llvm.atomic.load.sub.*</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8059</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8060
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]8061<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8062
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]8063<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8064<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.load.sub</tt> on
8065 any integer bit width and for different address spaces. Not all targets
8066 support all bit widths however.</p>
8067
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]8068<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]8069 declare i8 @llvm.atomic.load.sub.i8.p0i32(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
8070 declare i16 @llvm.atomic.load.sub.i16.p0i32(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
8071 declare i32 @llvm.atomic.load.sub.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
8072 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]8073</pre>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]8074
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8075<h5>Overview:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]8076<p>This intrinsic subtracts <tt>delta</tt> to the value stored in memory at
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8077 <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.</p>
8078
8079<h5>Arguments:</h5>
8080<p>The intrinsic takes two arguments, the first a pointer to an integer value
8081 and the second an integer value. The result is also an integer value. These
8082 integer types can have any bit width, but they must all have the same bit
8083 width. The targets may only lower integer representations they support.</p>
8084
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]8085<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8086<p>This intrinsic does a series of operations atomically. It first loads the
8087 value stored at <tt>ptr</tt>. It then subtracts <tt>delta</tt>, stores the
8088 result to <tt>ptr</tt>. It yields the original value stored
8089 at <tt>ptr</tt>.</p>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]8090
8091<h5>Examples:</h5>
8092<pre>
Victor Hernandeza70c6df2009-10-26 23:44:29 +0000[diff] [blame]8093%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
8094%ptr = bitcast i8* %mallocP to i32*
8095 store i32 8, %ptr
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]8096%result1 = call i32 @llvm.atomic.load.sub.i32.p0i32(i32* %ptr, i32 4)
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]8097 <i>; yields {i32}:result1 = 8</i>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]8098%result2 = call i32 @llvm.atomic.load.sub.i32.p0i32(i32* %ptr, i32 2)
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]8099 <i>; yields {i32}:result2 = 4</i>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]8100%result3 = call i32 @llvm.atomic.load.sub.i32.p0i32(i32* %ptr, i32 5)
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]8101 <i>; yields {i32}:result3 = 2</i>
8102%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = -3</i>
8103</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8104
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]8105</div>
8106
8107<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8108<h4>
8109 <a name="int_atomic_load_and">
8110 '<tt>llvm.atomic.load.and.*</tt>' Intrinsic
8111 </a>
8112 <br>
8113 <a name="int_atomic_load_nand">
8114 '<tt>llvm.atomic.load.nand.*</tt>' Intrinsic
8115 </a>
8116 <br>
8117 <a name="int_atomic_load_or">
8118 '<tt>llvm.atomic.load.or.*</tt>' Intrinsic
8119 </a>
8120 <br>
8121 <a name="int_atomic_load_xor">
8122 '<tt>llvm.atomic.load.xor.*</tt>' Intrinsic
8123 </a>
8124</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8125
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]8126<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8127
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]8128<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8129<p>These are overloaded intrinsics. You can
8130 use <tt>llvm.atomic.load_and</tt>, <tt>llvm.atomic.load_nand</tt>,
8131 <tt>llvm.atomic.load_or</tt>, and <tt>llvm.atomic.load_xor</tt> on any integer
8132 bit width and for different address spaces. Not all targets support all bit
8133 widths however.</p>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]8134
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8135<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]8136 declare i8 @llvm.atomic.load.and.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
8137 declare i16 @llvm.atomic.load.and.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
8138 declare i32 @llvm.atomic.load.and.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
8139 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]8140</pre>
8141
8142<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]8143 declare i8 @llvm.atomic.load.or.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
8144 declare i16 @llvm.atomic.load.or.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
8145 declare i32 @llvm.atomic.load.or.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
8146 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]8147</pre>
8148
8149<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]8150 declare i8 @llvm.atomic.load.nand.i8.p0i32(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
8151 declare i16 @llvm.atomic.load.nand.i16.p0i32(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
8152 declare i32 @llvm.atomic.load.nand.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
8153 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]8154</pre>
8155
8156<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]8157 declare i8 @llvm.atomic.load.xor.i8.p0i32(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
8158 declare i16 @llvm.atomic.load.xor.i16.p0i32(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
8159 declare i32 @llvm.atomic.load.xor.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
8160 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]8161</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8162
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]8163<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8164<p>These intrinsics bitwise the operation (and, nand, or, xor) <tt>delta</tt> to
8165 the value stored in memory at <tt>ptr</tt>. It yields the original value
8166 at <tt>ptr</tt>.</p>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]8167
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8168<h5>Arguments:</h5>
8169<p>These intrinsics take two arguments, the first a pointer to an integer value
8170 and the second an integer value. The result is also an integer value. These
8171 integer types can have any bit width, but they must all have the same bit
8172 width. The targets may only lower integer representations they support.</p>
8173
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]8174<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8175<p>These intrinsics does a series of operations atomically. They first load the
8176 value stored at <tt>ptr</tt>. They then do the bitwise
8177 operation <tt>delta</tt>, store the result to <tt>ptr</tt>. They yield the
8178 original value stored at <tt>ptr</tt>.</p>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]8179
8180<h5>Examples:</h5>
8181<pre>
Victor Hernandeza70c6df2009-10-26 23:44:29 +0000[diff] [blame]8182%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
8183%ptr = bitcast i8* %mallocP to i32*
8184 store i32 0x0F0F, %ptr
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]8185%result0 = call i32 @llvm.atomic.load.nand.i32.p0i32(i32* %ptr, i32 0xFF)
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]8186 <i>; yields {i32}:result0 = 0x0F0F</i>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]8187%result1 = call i32 @llvm.atomic.load.and.i32.p0i32(i32* %ptr, i32 0xFF)
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]8188 <i>; yields {i32}:result1 = 0xFFFFFFF0</i>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]8189%result2 = call i32 @llvm.atomic.load.or.i32.p0i32(i32* %ptr, i32 0F)
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]8190 <i>; yields {i32}:result2 = 0xF0</i>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]8191%result3 = call i32 @llvm.atomic.load.xor.i32.p0i32(i32* %ptr, i32 0F)
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]8192 <i>; yields {i32}:result3 = FF</i>
8193%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = F0</i>
8194</pre>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]8195
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8196</div>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]8197
8198<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8199<h4>
8200 <a name="int_atomic_load_max">
8201 '<tt>llvm.atomic.load.max.*</tt>' Intrinsic
8202 </a>
8203 <br>
8204 <a name="int_atomic_load_min">
8205 '<tt>llvm.atomic.load.min.*</tt>' Intrinsic
8206 </a>
8207 <br>
8208 <a name="int_atomic_load_umax">
8209 '<tt>llvm.atomic.load.umax.*</tt>' Intrinsic
8210 </a>
8211 <br>
8212 <a name="int_atomic_load_umin">
8213 '<tt>llvm.atomic.load.umin.*</tt>' Intrinsic
8214 </a>
8215</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8216
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]8217<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8218
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]8219<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8220<p>These are overloaded intrinsics. You can use <tt>llvm.atomic.load_max</tt>,
8221 <tt>llvm.atomic.load_min</tt>, <tt>llvm.atomic.load_umax</tt>, and
8222 <tt>llvm.atomic.load_umin</tt> on any integer bit width and for different
8223 address spaces. Not all targets support all bit widths however.</p>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]8224
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8225<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]8226 declare i8 @llvm.atomic.load.max.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
8227 declare i16 @llvm.atomic.load.max.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
8228 declare i32 @llvm.atomic.load.max.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
8229 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]8230</pre>
8231
8232<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]8233 declare i8 @llvm.atomic.load.min.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
8234 declare i16 @llvm.atomic.load.min.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
8235 declare i32 @llvm.atomic.load.min.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
8236 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]8237</pre>
8238
8239<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]8240 declare i8 @llvm.atomic.load.umax.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
8241 declare i16 @llvm.atomic.load.umax.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
8242 declare i32 @llvm.atomic.load.umax.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
8243 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]8244</pre>
8245
8246<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]8247 declare i8 @llvm.atomic.load.umin.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
8248 declare i16 @llvm.atomic.load.umin.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
8249 declare i32 @llvm.atomic.load.umin.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
8250 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]8251</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8252
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]8253<h5>Overview:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]8254<p>These intrinsics takes the signed or unsigned minimum or maximum of
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8255 <tt>delta</tt> and the value stored in memory at <tt>ptr</tt>. It yields the
8256 original value at <tt>ptr</tt>.</p>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]8257
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8258<h5>Arguments:</h5>
8259<p>These intrinsics take two arguments, the first a pointer to an integer value
8260 and the second an integer value. The result is also an integer value. These
8261 integer types can have any bit width, but they must all have the same bit
8262 width. The targets may only lower integer representations they support.</p>
8263
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]8264<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8265<p>These intrinsics does a series of operations atomically. They first load the
8266 value stored at <tt>ptr</tt>. They then do the signed or unsigned min or
8267 max <tt>delta</tt> and the value, store the result to <tt>ptr</tt>. They
8268 yield the original value stored at <tt>ptr</tt>.</p>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]8269
8270<h5>Examples:</h5>
8271<pre>
Victor Hernandeza70c6df2009-10-26 23:44:29 +0000[diff] [blame]8272%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
8273%ptr = bitcast i8* %mallocP to i32*
8274 store i32 7, %ptr
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]8275%result0 = call i32 @llvm.atomic.load.min.i32.p0i32(i32* %ptr, i32 -2)
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]8276 <i>; yields {i32}:result0 = 7</i>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]8277%result1 = call i32 @llvm.atomic.load.max.i32.p0i32(i32* %ptr, i32 8)
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]8278 <i>; yields {i32}:result1 = -2</i>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]8279%result2 = call i32 @llvm.atomic.load.umin.i32.p0i32(i32* %ptr, i32 10)
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]8280 <i>; yields {i32}:result2 = 8</i>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]8281%result3 = call i32 @llvm.atomic.load.umax.i32.p0i32(i32* %ptr, i32 30)
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]8282 <i>; yields {i32}:result3 = 8</i>
8283%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 30</i>
8284</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8285
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]8286</div>
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]8287
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]8288</div>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]8289
8290<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8291<h3>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]8292 <a name="int_memorymarkers">Memory Use Markers</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8293</h3>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]8294
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]8295<div>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]8296
8297<p>This class of intrinsics exists to information about the lifetime of memory
8298 objects and ranges where variables are immutable.</p>
8299
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]8300<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8301<h4>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]8302 <a name="int_lifetime_start">'<tt>llvm.lifetime.start</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8303</h4>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]8304
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]8305<div>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]8306
8307<h5>Syntax:</h5>
8308<pre>
8309 declare void @llvm.lifetime.start(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
8310</pre>
8311
8312<h5>Overview:</h5>
8313<p>The '<tt>llvm.lifetime.start</tt>' intrinsic specifies the start of a memory
8314 object's lifetime.</p>
8315
8316<h5>Arguments:</h5>
Nick Lewycky9bc89042009-10-13 07:57:33 +0000[diff] [blame]8317<p>The first argument is a constant integer representing the size of the
8318 object, or -1 if it is variable sized. The second argument is a pointer to
8319 the object.</p>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]8320
8321<h5>Semantics:</h5>
8322<p>This intrinsic indicates that before this point in the code, the value of the
8323 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]8324 never be used and has an undefined value. A load from the pointer that
8325 precedes this intrinsic can be replaced with
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]8326 <tt>'<a href="#undefvalues">undef</a>'</tt>.</p>
8327
8328</div>
8329
8330<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8331<h4>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]8332 <a name="int_lifetime_end">'<tt>llvm.lifetime.end</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8333</h4>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]8334
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]8335<div>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]8336
8337<h5>Syntax:</h5>
8338<pre>
8339 declare void @llvm.lifetime.end(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
8340</pre>
8341
8342<h5>Overview:</h5>
8343<p>The '<tt>llvm.lifetime.end</tt>' intrinsic specifies the end of a memory
8344 object's lifetime.</p>
8345
8346<h5>Arguments:</h5>
Nick Lewycky9bc89042009-10-13 07:57:33 +0000[diff] [blame]8347<p>The first argument is a constant integer representing the size of the
8348 object, or -1 if it is variable sized. The second argument is a pointer to
8349 the object.</p>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]8350
8351<h5>Semantics:</h5>
8352<p>This intrinsic indicates that after this point in the code, the value of the
8353 memory pointed to by <tt>ptr</tt> is dead. This means that it is known to
8354 never be used and has an undefined value. Any stores into the memory object
8355 following this intrinsic may be removed as dead.
8356
8357</div>
8358
8359<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8360<h4>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]8361 <a name="int_invariant_start">'<tt>llvm.invariant.start</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8362</h4>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]8363
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]8364<div>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]8365
8366<h5>Syntax:</h5>
8367<pre>
Nick Lewycky2965d3e2010-11-30 04:13:41 +0000[diff] [blame]8368 declare {}* @llvm.invariant.start(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]8369</pre>
8370
8371<h5>Overview:</h5>
8372<p>The '<tt>llvm.invariant.start</tt>' intrinsic specifies that the contents of
8373 a memory object will not change.</p>
8374
8375<h5>Arguments:</h5>
Nick Lewycky9bc89042009-10-13 07:57:33 +0000[diff] [blame]8376<p>The first argument is a constant integer representing the size of the
8377 object, or -1 if it is variable sized. The second argument is a pointer to
8378 the object.</p>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]8379
8380<h5>Semantics:</h5>
8381<p>This intrinsic indicates that until an <tt>llvm.invariant.end</tt> that uses
8382 the return value, the referenced memory location is constant and
8383 unchanging.</p>
8384
8385</div>
8386
8387<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8388<h4>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]8389 <a name="int_invariant_end">'<tt>llvm.invariant.end</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8390</h4>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]8391
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]8392<div>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]8393
8394<h5>Syntax:</h5>
8395<pre>
8396 declare void @llvm.invariant.end({}* &lt;start&gt;, i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
8397</pre>
8398
8399<h5>Overview:</h5>
8400<p>The '<tt>llvm.invariant.end</tt>' intrinsic specifies that the contents of
8401 a memory object are mutable.</p>
8402
8403<h5>Arguments:</h5>
8404<p>The first argument is the matching <tt>llvm.invariant.start</tt> intrinsic.
Nick Lewycky9bc89042009-10-13 07:57:33 +0000[diff] [blame]8405 The second argument is a constant integer representing the size of the
8406 object, or -1 if it is variable sized and the third argument is a pointer
8407 to the object.</p>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]8408
8409<h5>Semantics:</h5>
8410<p>This intrinsic indicates that the memory is mutable again.</p>
8411
8412</div>
8413
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]8414</div>
8415
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]8416<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8417<h3>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]8418 <a name="int_general">General Intrinsics</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8419</h3>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]8420
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]8421<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8422
8423<p>This class of intrinsics is designed to be generic and has no specific
8424 purpose.</p>
8425
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]8426<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8427<h4>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]8428 <a name="int_var_annotation">'<tt>llvm.var.annotation</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8429</h4>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]8430
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]8431<div>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]8432
8433<h5>Syntax:</h5>
8434<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]8435 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]8436</pre>
8437
8438<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8439<p>The '<tt>llvm.var.annotation</tt>' intrinsic.</p>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]8440
8441<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8442<p>The first argument is a pointer to a value, the second is a pointer to a
8443 global string, the third is a pointer to a global string which is the source
8444 file name, and the last argument is the line number.</p>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]8445
8446<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8447<p>This intrinsic allows annotation of local variables with arbitrary strings.
8448 This can be useful for special purpose optimizations that want to look for
John Criswellf0d536a2011-08-19 16:57:55 +0000[diff] [blame]8449 these annotations. These have no other defined use; they are ignored by code
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8450 generation and optimization.</p>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]8451
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]8452</div>
8453
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]8454<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8455<h4>
Tanya Lattner0186a652007-09-21 23:57:59 +0000[diff] [blame]8456 <a name="int_annotation">'<tt>llvm.annotation.*</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8457</h4>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]8458
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]8459<div>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]8460
8461<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8462<p>This is an overloaded intrinsic. You can use '<tt>llvm.annotation</tt>' on
8463 any integer bit width.</p>
8464
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]8465<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]8466 declare i8 @llvm.annotation.i8(i8 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
8467 declare i16 @llvm.annotation.i16(i16 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
8468 declare i32 @llvm.annotation.i32(i32 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
8469 declare i64 @llvm.annotation.i64(i64 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
8470 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]8471</pre>
8472
8473<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8474<p>The '<tt>llvm.annotation</tt>' intrinsic.</p>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]8475
8476<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8477<p>The first argument is an integer value (result of some expression), the
8478 second is a pointer to a global string, the third is a pointer to a global
8479 string which is the source file name, and the last argument is the line
8480 number. It returns the value of the first argument.</p>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]8481
8482<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8483<p>This intrinsic allows annotations to be put on arbitrary expressions with
8484 arbitrary strings. This can be useful for special purpose optimizations that
John Criswellf0d536a2011-08-19 16:57:55 +0000[diff] [blame]8485 want to look for these annotations. These have no other defined use; they
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8486 are ignored by code generation and optimization.</p>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]8487
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]8488</div>
Jim Laskey2211f492007-03-14 19:31:19 +0000[diff] [blame]8489
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]8490<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8491<h4>
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]8492 <a name="int_trap">'<tt>llvm.trap</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8493</h4>
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]8494
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]8495<div>
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]8496
8497<h5>Syntax:</h5>
8498<pre>
8499 declare void @llvm.trap()
8500</pre>
8501
8502<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8503<p>The '<tt>llvm.trap</tt>' intrinsic.</p>
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]8504
8505<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8506<p>None.</p>
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]8507
8508<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8509<p>This intrinsics is lowered to the target dependent trap instruction. If the
8510 target does not have a trap instruction, this intrinsic will be lowered to
8511 the call of the <tt>abort()</tt> function.</p>
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]8512
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]8513</div>
8514
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]8515<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8516<h4>
Misha Brukman50de2b22008-11-22 23:55:29 +0000[diff] [blame]8517 <a name="int_stackprotector">'<tt>llvm.stackprotector</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8518</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8519
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]8520<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8521
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]8522<h5>Syntax:</h5>
8523<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]8524 declare void @llvm.stackprotector(i8* &lt;guard&gt;, i8** &lt;slot&gt;)
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]8525</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8526
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]8527<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8528<p>The <tt>llvm.stackprotector</tt> intrinsic takes the <tt>guard</tt> and
8529 stores it onto the stack at <tt>slot</tt>. The stack slot is adjusted to
8530 ensure that it is placed on the stack before local variables.</p>
8531
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]8532<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8533<p>The <tt>llvm.stackprotector</tt> intrinsic requires two pointer
8534 arguments. The first argument is the value loaded from the stack
8535 guard <tt>@__stack_chk_guard</tt>. The second variable is an <tt>alloca</tt>
8536 that has enough space to hold the value of the guard.</p>
8537
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]8538<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8539<p>This intrinsic causes the prologue/epilogue inserter to force the position of
8540 the <tt>AllocaInst</tt> stack slot to be before local variables on the
8541 stack. This is to ensure that if a local variable on the stack is
8542 overwritten, it will destroy the value of the guard. When the function exits,
Bill Wendling6bbe0912010-10-27 01:07:41 +0000[diff] [blame]8543 the guard on the stack is checked against the original guard. If they are
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8544 different, then the program aborts by calling the <tt>__stack_chk_fail()</tt>
8545 function.</p>
8546
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]8547</div>
8548
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]8549<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8550<h4>
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]8551 <a name="int_objectsize">'<tt>llvm.objectsize</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8552</h4>
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]8553
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]8554<div>
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]8555
8556<h5>Syntax:</h5>
8557<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]8558 declare i32 @llvm.objectsize.i32(i8* &lt;object&gt;, i1 &lt;type&gt;)
8559 declare i64 @llvm.objectsize.i64(i8* &lt;object&gt;, i1 &lt;type&gt;)
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]8560</pre>
8561
8562<h5>Overview:</h5>
Bill Wendling6bbe0912010-10-27 01:07:41 +0000[diff] [blame]8563<p>The <tt>llvm.objectsize</tt> intrinsic is designed to provide information to
8564 the optimizers to determine at compile time whether a) an operation (like
8565 memcpy) will overflow a buffer that corresponds to an object, or b) that a
8566 runtime check for overflow isn't necessary. An object in this context means
8567 an allocation of a specific class, structure, array, or other object.</p>
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]8568
8569<h5>Arguments:</h5>
Bill Wendling6bbe0912010-10-27 01:07:41 +0000[diff] [blame]8570<p>The <tt>llvm.objectsize</tt> intrinsic takes two arguments. The first
Eric Christopher31e39bd2009-12-23 00:29:49 +0000[diff] [blame]8571 argument is a pointer to or into the <tt>object</tt>. The second argument
Bill Wendling6bbe0912010-10-27 01:07:41 +0000[diff] [blame]8572 is a boolean 0 or 1. This argument determines whether you want the
8573 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]8574 1, variables are not allowed.</p>
8575
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]8576<h5>Semantics:</h5>
8577<p>The <tt>llvm.objectsize</tt> intrinsic is lowered to either a constant
Bill Wendling6bbe0912010-10-27 01:07:41 +0000[diff] [blame]8578 representing the size of the object concerned, or <tt>i32/i64 -1 or 0</tt>,
8579 depending on the <tt>type</tt> argument, if the size cannot be determined at
8580 compile time.</p>
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]8581
8582</div>
8583
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]8584</div>
8585
8586</div>
8587
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]8588<!-- *********************************************************************** -->
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]8589<hr>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]8590<address>
8591 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
Misha Brukman86242e12008-12-11 17:34:48 +0000[diff] [blame]8592 src="http://jigsaw.w3.org/css-validator/images/vcss-blue" alt="Valid CSS"></a>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]8593 <a href="http://validator.w3.org/check/referer"><img
Misha Brukman86242e12008-12-11 17:34:48 +0000[diff] [blame]8594 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]8595
8596 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
NAKAMURA Takumica46f5a2011-04-09 02:13:37 +0000[diff] [blame]8597 <a href="http://llvm.org/">The LLVM Compiler Infrastructure</a><br>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]8598 Last modified: $Date$
8599</address>
Chris Lattnerb8f816e2008-01-04 04:33:49 +0000[diff] [blame]8600
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]8601</body>
8602</html>