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gerrit-public.fairphone.software / toolchain / llvm-project / ca46f5a3b5d75995b2a2807bc885f308e7009372 / . / llvm / docs / LangRef.html
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4<head>
5 <title>LLVM Assembly Language Reference Manual</title>
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7 <meta name="author" content="Chris Lattner">
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]8 <meta name="description"
Reid Spencercb84e432004-08-26 20:44:00 +0000[diff] [blame]9 content="LLVM Assembly Language Reference Manual.">
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]10 <link rel="stylesheet" href="llvm.css" type="text/css">
11</head>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]12
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]13<body>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]14
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]15<div class="doc_title"> LLVM Language Reference Manual </div>
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>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]56 </ol>
57 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]58 <li><a href="#typesystem">Type System</a>
59 <ol>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]60 <li><a href="#t_classifications">Type Classifications</a></li>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]61 <li><a href="#t_primitive">Primitive Types</a>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]62 <ol>
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]63 <li><a href="#t_integer">Integer Type</a></li>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]64 <li><a href="#t_floating">Floating Point Types</a></li>
Dale Johannesen33e5c352010-10-01 00:48:59 +0000[diff] [blame]65 <li><a href="#t_x86mmx">X86mmx Type</a></li>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]66 <li><a href="#t_void">Void Type</a></li>
67 <li><a href="#t_label">Label Type</a></li>
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]68 <li><a href="#t_metadata">Metadata Type</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]69 </ol>
70 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]71 <li><a href="#t_derived">Derived Types</a>
72 <ol>
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]73 <li><a href="#t_aggregate">Aggregate Types</a>
74 <ol>
75 <li><a href="#t_array">Array Type</a></li>
76 <li><a href="#t_struct">Structure Type</a></li>
77 <li><a href="#t_pstruct">Packed Structure Type</a></li>
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]78 <li><a href="#t_vector">Vector Type</a></li>
79 </ol>
80 </li>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]81 <li><a href="#t_function">Function Type</a></li>
82 <li><a href="#t_pointer">Pointer Type</a></li>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]83 <li><a href="#t_opaque">Opaque Type</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]84 </ol>
85 </li>
Chris Lattnercf7a5842009-02-02 07:32:36 +0000[diff] [blame]86 <li><a href="#t_uprefs">Type Up-references</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]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>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]127 <li><a href="#i_unreachable">'<tt>unreachable</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]128 </ol>
129 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]130 <li><a href="#binaryops">Binary Operations</a>
131 <ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]132 <li><a href="#i_add">'<tt>add</tt>' Instruction</a></li>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]133 <li><a href="#i_fadd">'<tt>fadd</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]134 <li><a href="#i_sub">'<tt>sub</tt>' Instruction</a></li>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]135 <li><a href="#i_fsub">'<tt>fsub</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]136 <li><a href="#i_mul">'<tt>mul</tt>' Instruction</a></li>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]137 <li><a href="#i_fmul">'<tt>fmul</tt>' Instruction</a></li>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]138 <li><a href="#i_udiv">'<tt>udiv</tt>' Instruction</a></li>
139 <li><a href="#i_sdiv">'<tt>sdiv</tt>' Instruction</a></li>
140 <li><a href="#i_fdiv">'<tt>fdiv</tt>' Instruction</a></li>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]141 <li><a href="#i_urem">'<tt>urem</tt>' Instruction</a></li>
142 <li><a href="#i_srem">'<tt>srem</tt>' Instruction</a></li>
143 <li><a href="#i_frem">'<tt>frem</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]144 </ol>
145 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]146 <li><a href="#bitwiseops">Bitwise Binary Operations</a>
147 <ol>
Reid Spencer2ab01932007-02-02 13:57:07 +0000[diff] [blame]148 <li><a href="#i_shl">'<tt>shl</tt>' Instruction</a></li>
149 <li><a href="#i_lshr">'<tt>lshr</tt>' Instruction</a></li>
150 <li><a href="#i_ashr">'<tt>ashr</tt>' Instruction</a></li>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]151 <li><a href="#i_and">'<tt>and</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]152 <li><a href="#i_or">'<tt>or</tt>' Instruction</a></li>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]153 <li><a href="#i_xor">'<tt>xor</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]154 </ol>
155 </li>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]156 <li><a href="#vectorops">Vector Operations</a>
157 <ol>
158 <li><a href="#i_extractelement">'<tt>extractelement</tt>' Instruction</a></li>
159 <li><a href="#i_insertelement">'<tt>insertelement</tt>' Instruction</a></li>
160 <li><a href="#i_shufflevector">'<tt>shufflevector</tt>' Instruction</a></li>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]161 </ol>
162 </li>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]163 <li><a href="#aggregateops">Aggregate Operations</a>
164 <ol>
165 <li><a href="#i_extractvalue">'<tt>extractvalue</tt>' Instruction</a></li>
166 <li><a href="#i_insertvalue">'<tt>insertvalue</tt>' Instruction</a></li>
167 </ol>
168 </li>
Chris Lattner6ab66722006-08-15 00:45:58 +0000[diff] [blame]169 <li><a href="#memoryops">Memory Access and Addressing Operations</a>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]170 <ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]171 <li><a href="#i_alloca">'<tt>alloca</tt>' Instruction</a></li>
Robert Bocchino820bc75b2006-02-17 21:18:08 +0000[diff] [blame]172 <li><a href="#i_load">'<tt>load</tt>' Instruction</a></li>
173 <li><a href="#i_store">'<tt>store</tt>' Instruction</a></li>
174 <li><a href="#i_getelementptr">'<tt>getelementptr</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]175 </ol>
176 </li>
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]177 <li><a href="#convertops">Conversion Operations</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]178 <ol>
179 <li><a href="#i_trunc">'<tt>trunc .. to</tt>' Instruction</a></li>
180 <li><a href="#i_zext">'<tt>zext .. to</tt>' Instruction</a></li>
181 <li><a href="#i_sext">'<tt>sext .. to</tt>' Instruction</a></li>
182 <li><a href="#i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a></li>
183 <li><a href="#i_fpext">'<tt>fpext .. to</tt>' Instruction</a></li>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]184 <li><a href="#i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a></li>
185 <li><a href="#i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a></li>
186 <li><a href="#i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a></li>
187 <li><a href="#i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a></li>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]188 <li><a href="#i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a></li>
189 <li><a href="#i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a></li>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]190 <li><a href="#i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a></li>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]191 </ol>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]192 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]193 <li><a href="#otherops">Other Operations</a>
194 <ol>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]195 <li><a href="#i_icmp">'<tt>icmp</tt>' Instruction</a></li>
196 <li><a href="#i_fcmp">'<tt>fcmp</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]197 <li><a href="#i_phi">'<tt>phi</tt>' Instruction</a></li>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]198 <li><a href="#i_select">'<tt>select</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]199 <li><a href="#i_call">'<tt>call</tt>' Instruction</a></li>
Chris Lattner33337472006-01-13 23:26:01 +0000[diff] [blame]200 <li><a href="#i_va_arg">'<tt>va_arg</tt>' Instruction</a></li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]201 </ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]202 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]203 </ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]204 </li>
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]205 <li><a href="#intrinsics">Intrinsic Functions</a>
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]206 <ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]207 <li><a href="#int_varargs">Variable Argument Handling Intrinsics</a>
208 <ol>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]209 <li><a href="#int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a></li>
210 <li><a href="#int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a></li>
211 <li><a href="#int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]212 </ol>
213 </li>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]214 <li><a href="#int_gc">Accurate Garbage Collection Intrinsics</a>
215 <ol>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]216 <li><a href="#int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a></li>
217 <li><a href="#int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a></li>
218 <li><a href="#int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a></li>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]219 </ol>
220 </li>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]221 <li><a href="#int_codegen">Code Generator Intrinsics</a>
222 <ol>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]223 <li><a href="#int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a></li>
224 <li><a href="#int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a></li>
225 <li><a href="#int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a></li>
226 <li><a href="#int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a></li>
227 <li><a href="#int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a></li>
228 <li><a href="#int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a></li>
Dan Gohmane58f7b32010-05-26 21:56:15 +0000[diff] [blame]229 <li><a href="#int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a></li>
John Criswellaa1c3c12004-04-09 16:43:20 +0000[diff] [blame]230 </ol>
231 </li>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]232 <li><a href="#int_libc">Standard C Library Intrinsics</a>
233 <ol>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]234 <li><a href="#int_memcpy">'<tt>llvm.memcpy.*</tt>' Intrinsic</a></li>
235 <li><a href="#int_memmove">'<tt>llvm.memmove.*</tt>' Intrinsic</a></li>
236 <li><a href="#int_memset">'<tt>llvm.memset.*</tt>' Intrinsic</a></li>
237 <li><a href="#int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a></li>
238 <li><a href="#int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a></li>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]239 <li><a href="#int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a></li>
240 <li><a href="#int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a></li>
241 <li><a href="#int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a></li>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]242 </ol>
243 </li>
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]244 <li><a href="#int_manip">Bit Manipulation Intrinsics</a>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]245 <ol>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]246 <li><a href="#int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a></li>
Chris Lattnerb748c672006-01-16 22:34:14 +0000[diff] [blame]247 <li><a href="#int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic </a></li>
248 <li><a href="#int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic </a></li>
249 <li><a href="#int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic </a></li>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]250 </ol>
251 </li>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]252 <li><a href="#int_overflow">Arithmetic with Overflow Intrinsics</a>
253 <ol>
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]254 <li><a href="#int_sadd_overflow">'<tt>llvm.sadd.with.overflow.*</tt> Intrinsics</a></li>
255 <li><a href="#int_uadd_overflow">'<tt>llvm.uadd.with.overflow.*</tt> Intrinsics</a></li>
256 <li><a href="#int_ssub_overflow">'<tt>llvm.ssub.with.overflow.*</tt> Intrinsics</a></li>
257 <li><a href="#int_usub_overflow">'<tt>llvm.usub.with.overflow.*</tt> Intrinsics</a></li>
258 <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]259 <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]260 </ol>
261 </li>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]262 <li><a href="#int_fp16">Half Precision Floating Point Intrinsics</a>
263 <ol>
Chris Lattnerbbd8bd32010-03-14 23:03:31 +0000[diff] [blame]264 <li><a href="#int_convert_to_fp16">'<tt>llvm.convert.to.fp16</tt>' Intrinsic</a></li>
265 <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]266 </ol>
267 </li>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]268 <li><a href="#int_debugger">Debugger intrinsics</a></li>
Jim Laskey2211f492007-03-14 19:31:19 +0000[diff] [blame]269 <li><a href="#int_eh">Exception Handling intrinsics</a></li>
Duncan Sands86e01192007-09-11 14:10:23 +0000[diff] [blame]270 <li><a href="#int_trampoline">Trampoline Intrinsic</a>
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]271 <ol>
272 <li><a href="#int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a></li>
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]273 </ol>
274 </li>
Bill Wendlingf85850f2008-11-18 22:10:53 +0000[diff] [blame]275 <li><a href="#int_atomics">Atomic intrinsics</a>
276 <ol>
277 <li><a href="#int_memory_barrier"><tt>llvm.memory_barrier</tt></a></li>
278 <li><a href="#int_atomic_cmp_swap"><tt>llvm.atomic.cmp.swap</tt></a></li>
279 <li><a href="#int_atomic_swap"><tt>llvm.atomic.swap</tt></a></li>
280 <li><a href="#int_atomic_load_add"><tt>llvm.atomic.load.add</tt></a></li>
281 <li><a href="#int_atomic_load_sub"><tt>llvm.atomic.load.sub</tt></a></li>
282 <li><a href="#int_atomic_load_and"><tt>llvm.atomic.load.and</tt></a></li>
283 <li><a href="#int_atomic_load_nand"><tt>llvm.atomic.load.nand</tt></a></li>
284 <li><a href="#int_atomic_load_or"><tt>llvm.atomic.load.or</tt></a></li>
285 <li><a href="#int_atomic_load_xor"><tt>llvm.atomic.load.xor</tt></a></li>
286 <li><a href="#int_atomic_load_max"><tt>llvm.atomic.load.max</tt></a></li>
287 <li><a href="#int_atomic_load_min"><tt>llvm.atomic.load.min</tt></a></li>
288 <li><a href="#int_atomic_load_umax"><tt>llvm.atomic.load.umax</tt></a></li>
289 <li><a href="#int_atomic_load_umin"><tt>llvm.atomic.load.umin</tt></a></li>
290 </ol>
291 </li>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]292 <li><a href="#int_memorymarkers">Memory Use Markers</a>
293 <ol>
294 <li><a href="#int_lifetime_start"><tt>llvm.lifetime.start</tt></a></li>
295 <li><a href="#int_lifetime_end"><tt>llvm.lifetime.end</tt></a></li>
296 <li><a href="#int_invariant_start"><tt>llvm.invariant.start</tt></a></li>
297 <li><a href="#int_invariant_end"><tt>llvm.invariant.end</tt></a></li>
298 </ol>
299 </li>
Reid Spencer5b2cb0f2007-07-20 19:59:11 +0000[diff] [blame]300 <li><a href="#int_general">General intrinsics</a>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]301 <ol>
Reid Spencer5b2cb0f2007-07-20 19:59:11 +0000[diff] [blame]302 <li><a href="#int_var_annotation">
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]303 '<tt>llvm.var.annotation</tt>' Intrinsic</a></li>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]304 <li><a href="#int_annotation">
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]305 '<tt>llvm.annotation.*</tt>' Intrinsic</a></li>
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]306 <li><a href="#int_trap">
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]307 '<tt>llvm.trap</tt>' Intrinsic</a></li>
308 <li><a href="#int_stackprotector">
309 '<tt>llvm.stackprotector</tt>' Intrinsic</a></li>
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]310 <li><a href="#int_objectsize">
311 '<tt>llvm.objectsize</tt>' Intrinsic</a></li>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]312 </ol>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]313 </li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]314 </ol>
315 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]316</ol>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]317
318<div class="doc_author">
319 <p>Written by <a href="mailto:sabre@nondot.org">Chris Lattner</a>
320 and <a href="mailto:vadve@cs.uiuc.edu">Vikram Adve</a></p>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]321</div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]322
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]323<!-- *********************************************************************** -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]324<div class="doc_section"> <a name="abstract">Abstract </a></div>
325<!-- *********************************************************************** -->
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]326
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]327<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]328
329<p>This document is a reference manual for the LLVM assembly language. LLVM is
330 a Static Single Assignment (SSA) based representation that provides type
331 safety, low-level operations, flexibility, and the capability of representing
332 'all' high-level languages cleanly. It is the common code representation
333 used throughout all phases of the LLVM compilation strategy.</p>
334
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]335</div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]336
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]337<!-- *********************************************************************** -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]338<div class="doc_section"> <a name="introduction">Introduction</a> </div>
339<!-- *********************************************************************** -->
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]340
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]341<div class="doc_text">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]342
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]343<p>The LLVM code representation is designed to be used in three different forms:
344 as an in-memory compiler IR, as an on-disk bitcode representation (suitable
345 for fast loading by a Just-In-Time compiler), and as a human readable
346 assembly language representation. This allows LLVM to provide a powerful
347 intermediate representation for efficient compiler transformations and
348 analysis, while providing a natural means to debug and visualize the
349 transformations. The three different forms of LLVM are all equivalent. This
350 document describes the human readable representation and notation.</p>
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 representation aims to be light-weight and low-level while being
353 expressive, typed, and extensible at the same time. It aims to be a
354 "universal IR" of sorts, by being at a low enough level that high-level ideas
355 may be cleanly mapped to it (similar to how microprocessors are "universal
356 IR's", allowing many source languages to be mapped to them). By providing
357 type information, LLVM can be used as the target of optimizations: for
358 example, through pointer analysis, it can be proven that a C automatic
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]359 variable is never accessed outside of the current function, allowing it to
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]360 be promoted to a simple SSA value instead of a memory location.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]361
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]362</div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]363
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]364<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]365<div class="doc_subsubsection"> <a name="wellformed">Well-Formedness</a> </div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]366
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]367<div class="doc_text">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]368
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]369<p>It is important to note that this document describes 'well formed' LLVM
370 assembly language. There is a difference between what the parser accepts and
371 what is considered 'well formed'. For example, the following instruction is
372 syntactically okay, but not well formed:</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]373
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]374<pre class="doc_code">
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]375%x = <a href="#i_add">add</a> i32 1, %x
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]376</pre>
377
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]378<p>because the definition of <tt>%x</tt> does not dominate all of its uses. The
379 LLVM infrastructure provides a verification pass that may be used to verify
380 that an LLVM module is well formed. This pass is automatically run by the
381 parser after parsing input assembly and by the optimizer before it outputs
382 bitcode. The violations pointed out by the verifier pass indicate bugs in
383 transformation passes or input to the parser.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]384
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]385</div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]386
Chris Lattner87a3dbe2007-10-03 17:34:29 +0000[diff] [blame]387<!-- Describe the typesetting conventions here. -->
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]388
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]389<!-- *********************************************************************** -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]390<div class="doc_section"> <a name="identifiers">Identifiers</a> </div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]391<!-- *********************************************************************** -->
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]392
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]393<div class="doc_text">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]394
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]395<p>LLVM identifiers come in two basic types: global and local. Global
396 identifiers (functions, global variables) begin with the <tt>'@'</tt>
397 character. Local identifiers (register names, types) begin with
398 the <tt>'%'</tt> character. Additionally, there are three different formats
399 for identifiers, for different purposes:</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]400
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]401<ol>
Reid Spencerb23b65f2007-08-07 14:34:28 +0000[diff] [blame]402 <li>Named values are represented as a string of characters with their prefix.
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]403 For example, <tt>%foo</tt>, <tt>@DivisionByZero</tt>,
404 <tt>%a.really.long.identifier</tt>. The actual regular expression used is
405 '<tt>[%@][a-zA-Z$._][a-zA-Z$._0-9]*</tt>'. Identifiers which require
406 other characters in their names can be surrounded with quotes. Special
407 characters may be escaped using <tt>"\xx"</tt> where <tt>xx</tt> is the
408 ASCII code for the character in hexadecimal. In this way, any character
409 can be used in a name value, even quotes themselves.</li>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]410
Reid Spencerb23b65f2007-08-07 14:34:28 +0000[diff] [blame]411 <li>Unnamed values are represented as an unsigned numeric value with their
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]412 prefix. For example, <tt>%12</tt>, <tt>@2</tt>, <tt>%44</tt>.</li>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]413
Reid Spencer8f08d802004-12-09 18:02:53 +0000[diff] [blame]414 <li>Constants, which are described in a <a href="#constants">section about
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]415 constants</a>, below.</li>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]416</ol>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]417
Reid Spencerb23b65f2007-08-07 14:34:28 +0000[diff] [blame]418<p>LLVM requires that values start with a prefix for two reasons: Compilers
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]419 don't need to worry about name clashes with reserved words, and the set of
420 reserved words may be expanded in the future without penalty. Additionally,
421 unnamed identifiers allow a compiler to quickly come up with a temporary
422 variable without having to avoid symbol table conflicts.</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]423
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]424<p>Reserved words in LLVM are very similar to reserved words in other
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]425 languages. There are keywords for different opcodes
426 ('<tt><a href="#i_add">add</a></tt>',
427 '<tt><a href="#i_bitcast">bitcast</a></tt>',
428 '<tt><a href="#i_ret">ret</a></tt>', etc...), for primitive type names
429 ('<tt><a href="#t_void">void</a></tt>',
430 '<tt><a href="#t_primitive">i32</a></tt>', etc...), and others. These
431 reserved words cannot conflict with variable names, because none of them
432 start with a prefix character (<tt>'%'</tt> or <tt>'@'</tt>).</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]433
434<p>Here is an example of LLVM code to multiply the integer variable
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]435 '<tt>%X</tt>' by 8:</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]436
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]437<p>The easy way:</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]438
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]439<pre class="doc_code">
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]440%result = <a href="#i_mul">mul</a> i32 %X, 8
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]441</pre>
442
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]443<p>After strength reduction:</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]444
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]445<pre class="doc_code">
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]446%result = <a href="#i_shl">shl</a> i32 %X, i8 3
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]447</pre>
448
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]449<p>And the hard way:</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]450
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]451<pre class="doc_code">
Gabor Greifbd0328f2009-10-28 13:05:07 +0000[diff] [blame]452%0 = <a href="#i_add">add</a> i32 %X, %X <i>; yields {i32}:%0</i>
453%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]454%result = <a href="#i_add">add</a> i32 %1, %1
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]455</pre>
456
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]457<p>This last way of multiplying <tt>%X</tt> by 8 illustrates several important
458 lexical features of LLVM:</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]459
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]460<ol>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]461 <li>Comments are delimited with a '<tt>;</tt>' and go until the end of
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]462 line.</li>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]463
464 <li>Unnamed temporaries are created when the result of a computation is not
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]465 assigned to a named value.</li>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]466
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]467 <li>Unnamed temporaries are numbered sequentially</li>
468</ol>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]469
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]470<p>It also shows a convention that we follow in this document. When
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]471 demonstrating instructions, we will follow an instruction with a comment that
472 defines the type and name of value produced. Comments are shown in italic
473 text.</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]474
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]475</div>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]476
477<!-- *********************************************************************** -->
478<div class="doc_section"> <a name="highlevel">High Level Structure</a> </div>
479<!-- *********************************************************************** -->
480
481<!-- ======================================================================= -->
482<div class="doc_subsection"> <a name="modulestructure">Module Structure</a>
483</div>
484
485<div class="doc_text">
486
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]487<p>LLVM programs are composed of "Module"s, each of which is a translation unit
488 of the input programs. Each module consists of functions, global variables,
489 and symbol table entries. Modules may be combined together with the LLVM
490 linker, which merges function (and global variable) definitions, resolves
491 forward declarations, and merges symbol table entries. Here is an example of
492 the "hello world" module:</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]493
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]494<pre class="doc_code">
Chris Lattner54a7be72010-08-17 17:13:42 +0000[diff] [blame]495<i>; Declare the string constant as a global constant.</i>&nbsp;
Nick Lewyckyfea7ddc2011-01-29 01:09:53 +0000[diff] [blame]496<a href="#identifiers">@.LC0</a> = <a href="#linkage_internal">internal</a>&nbsp;<a href="#globalvars">constant</a>&nbsp;<a href="#t_array">[13 x i8]</a> c"hello world\0A\00" <i>; [13 x i8]*</i>&nbsp;
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]497
Chris Lattner54a7be72010-08-17 17:13:42 +0000[diff] [blame]498<i>; External declaration of the puts function</i>&nbsp;
499<a href="#functionstructure">declare</a> i32 @puts(i8*) <i>; i32 (i8*)* </i>&nbsp;
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]500
501<i>; Definition of main function</i>
Chris Lattner54a7be72010-08-17 17:13:42 +0000[diff] [blame]502define i32 @main() { <i>; i32()* </i>&nbsp;
503 <i>; Convert [13 x i8]* to i8 *...</i>&nbsp;
504 %cast210 = <a href="#i_getelementptr">getelementptr</a> [13 x i8]* @.LC0, i64 0, i64 0 <i>; i8*</i>&nbsp;
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]505
Chris Lattner54a7be72010-08-17 17:13:42 +0000[diff] [blame]506 <i>; Call puts function to write out the string to stdout.</i>&nbsp;
507 <a href="#i_call">call</a> i32 @puts(i8* %cast210) <i>; i32</i>&nbsp;
508 <a href="#i_ret">ret</a> i32 0&nbsp;
509}
Devang Pateld1a89692010-01-11 19:35:55 +0000[diff] [blame]510
511<i>; Named metadata</i>
512!1 = metadata !{i32 41}
513!foo = !{!1, null}
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]514</pre>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]515
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]516<p>This example is made up of a <a href="#globalvars">global variable</a> named
Devang Pateld1a89692010-01-11 19:35:55 +0000[diff] [blame]517 "<tt>.LC0</tt>", an external declaration of the "<tt>puts</tt>" function,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]518 a <a href="#functionstructure">function definition</a> for
Devang Pateld1a89692010-01-11 19:35:55 +0000[diff] [blame]519 "<tt>main</tt>" and <a href="#namedmetadatastructure">named metadata</a>
520 "<tt>foo"</tt>.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]521
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]522<p>In general, a module is made up of a list of global values, where both
523 functions and global variables are global values. Global values are
524 represented by a pointer to a memory location (in this case, a pointer to an
525 array of char, and a pointer to a function), and have one of the
526 following <a href="#linkage">linkage types</a>.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]527
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]528</div>
529
530<!-- ======================================================================= -->
531<div class="doc_subsection">
532 <a name="linkage">Linkage Types</a>
533</div>
534
535<div class="doc_text">
536
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]537<p>All Global Variables and Functions have one of the following types of
538 linkage:</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]539
540<dl>
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]541 <dt><tt><b><a name="linkage_private">private</a></b></tt></dt>
Bill Wendling03bcd6e2010-07-01 21:55:59 +0000[diff] [blame]542 <dd>Global values with "<tt>private</tt>" linkage are only directly accessible
543 by objects in the current module. In particular, linking code into a
544 module with an private global value may cause the private to be renamed as
545 necessary to avoid collisions. Because the symbol is private to the
546 module, all references can be updated. This doesn't show up in any symbol
547 table in the object file.</dd>
Rafael Espindola6de96a12009-01-15 20:18:42 +0000[diff] [blame]548
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]549 <dt><tt><b><a name="linkage_linker_private">linker_private</a></b></tt></dt>
Bill Wendling03bcd6e2010-07-01 21:55:59 +0000[diff] [blame]550 <dd>Similar to <tt>private</tt>, but the symbol is passed through the
551 assembler and evaluated by the linker. Unlike normal strong symbols, they
552 are removed by the linker from the final linked image (executable or
553 dynamic library).</dd>
554
555 <dt><tt><b><a name="linkage_linker_private_weak">linker_private_weak</a></b></tt></dt>
556 <dd>Similar to "<tt>linker_private</tt>", but the symbol is weak. Note that
557 <tt>linker_private_weak</tt> symbols are subject to coalescing by the
558 linker. The symbols are removed by the linker from the final linked image
559 (executable or dynamic library).</dd>
Bill Wendlinga3c6f6b2009-07-20 01:03:30 +0000[diff] [blame]560
Bill Wendling578ee402010-08-20 22:05:50 +0000[diff] [blame]561 <dt><tt><b><a name="linkage_linker_private_weak_def_auto">linker_private_weak_def_auto</a></b></tt></dt>
562 <dd>Similar to "<tt>linker_private_weak</tt>", but it's known that the address
563 of the object is not taken. For instance, functions that had an inline
564 definition, but the compiler decided not to inline it. Note,
565 unlike <tt>linker_private</tt> and <tt>linker_private_weak</tt>,
566 <tt>linker_private_weak_def_auto</tt> may have only <tt>default</tt>
567 visibility. The symbols are removed by the linker from the final linked
568 image (executable or dynamic library).</dd>
569
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]570 <dt><tt><b><a name="linkage_internal">internal</a></b></tt></dt>
Bill Wendling36321712010-06-29 22:34:52 +0000[diff] [blame]571 <dd>Similar to private, but the value shows as a local symbol
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]572 (<tt>STB_LOCAL</tt> in the case of ELF) in the object file. This
573 corresponds to the notion of the '<tt>static</tt>' keyword in C.</dd>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]574
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]575 <dt><tt><b><a name="linkage_available_externally">available_externally</a></b></tt></dt>
Chris Lattner184f1be2009-04-13 05:44:34 +0000[diff] [blame]576 <dd>Globals with "<tt>available_externally</tt>" linkage are never emitted
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]577 into the object file corresponding to the LLVM module. They exist to
578 allow inlining and other optimizations to take place given knowledge of
579 the definition of the global, which is known to be somewhere outside the
580 module. Globals with <tt>available_externally</tt> linkage are allowed to
581 be discarded at will, and are otherwise the same as <tt>linkonce_odr</tt>.
582 This linkage type is only allowed on definitions, not declarations.</dd>
Chris Lattner184f1be2009-04-13 05:44:34 +0000[diff] [blame]583
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]584 <dt><tt><b><a name="linkage_linkonce">linkonce</a></b></tt></dt>
Chris Lattnere20b4702007-01-14 06:51:48 +0000[diff] [blame]585 <dd>Globals with "<tt>linkonce</tt>" linkage are merged with other globals of
Chris Lattner0de4caa2010-01-09 19:15:14 +0000[diff] [blame]586 the same name when linkage occurs. This can be used to implement
587 some forms of inline functions, templates, or other code which must be
588 generated in each translation unit that uses it, but where the body may
589 be overridden with a more definitive definition later. Unreferenced
590 <tt>linkonce</tt> globals are allowed to be discarded. Note that
591 <tt>linkonce</tt> linkage does not actually allow the optimizer to
592 inline the body of this function into callers because it doesn't know if
593 this definition of the function is the definitive definition within the
594 program or whether it will be overridden by a stronger definition.
595 To enable inlining and other optimizations, use "<tt>linkonce_odr</tt>"
596 linkage.</dd>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]597
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]598 <dt><tt><b><a name="linkage_weak">weak</a></b></tt></dt>
Chris Lattnerd0554882009-08-05 05:21:07 +0000[diff] [blame]599 <dd>"<tt>weak</tt>" linkage has the same merging semantics as
600 <tt>linkonce</tt> linkage, except that unreferenced globals with
601 <tt>weak</tt> linkage may not be discarded. This is used for globals that
602 are declared "weak" in C source code.</dd>
603
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]604 <dt><tt><b><a name="linkage_common">common</a></b></tt></dt>
Chris Lattnerd0554882009-08-05 05:21:07 +0000[diff] [blame]605 <dd>"<tt>common</tt>" linkage is most similar to "<tt>weak</tt>" linkage, but
606 they are used for tentative definitions in C, such as "<tt>int X;</tt>" at
607 global scope.
608 Symbols with "<tt>common</tt>" linkage are merged in the same way as
609 <tt>weak symbols</tt>, and they may not be deleted if unreferenced.
Chris Lattner0aff0b22009-08-05 05:41:44 +0000[diff] [blame]610 <tt>common</tt> symbols may not have an explicit section,
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]611 must have a zero initializer, and may not be marked '<a
Chris Lattner0aff0b22009-08-05 05:41:44 +0000[diff] [blame]612 href="#globalvars"><tt>constant</tt></a>'. Functions and aliases may not
613 have common linkage.</dd>
Chris Lattnerd0554882009-08-05 05:21:07 +0000[diff] [blame]614
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]615
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]616 <dt><tt><b><a name="linkage_appending">appending</a></b></tt></dt>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]617 <dd>"<tt>appending</tt>" linkage may only be applied to global variables of
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]618 pointer to array type. When two global variables with appending linkage
619 are linked together, the two global arrays are appended together. This is
620 the LLVM, typesafe, equivalent of having the system linker append together
621 "sections" with identical names when .o files are linked.</dd>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]622
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]623 <dt><tt><b><a name="linkage_externweak">extern_weak</a></b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]624 <dd>The semantics of this linkage follow the ELF object file model: the symbol
625 is weak until linked, if not linked, the symbol becomes null instead of
626 being an undefined reference.</dd>
Anton Korobeynikova0554d92007-01-12 19:20:47 +0000[diff] [blame]627
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]628 <dt><tt><b><a name="linkage_linkonce_odr">linkonce_odr</a></b></tt></dt>
629 <dt><tt><b><a name="linkage_weak_odr">weak_odr</a></b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]630 <dd>Some languages allow differing globals to be merged, such as two functions
631 with different semantics. Other languages, such as <tt>C++</tt>, ensure
Bill Wendling03bcd6e2010-07-01 21:55:59 +0000[diff] [blame]632 that only equivalent globals are ever merged (the "one definition rule"
633 &mdash; "ODR"). Such languages can use the <tt>linkonce_odr</tt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]634 and <tt>weak_odr</tt> linkage types to indicate that the global will only
635 be merged with equivalent globals. These linkage types are otherwise the
636 same as their non-<tt>odr</tt> versions.</dd>
Duncan Sands12da8ce2009-03-07 15:45:40 +0000[diff] [blame]637
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]638 <dt><tt><b><a name="linkage_external">externally visible</a></b></tt>:</dt>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]639 <dd>If none of the above identifiers are used, the global is externally
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]640 visible, meaning that it participates in linkage and can be used to
641 resolve external symbol references.</dd>
Reid Spencer7972c472007-04-11 23:49:50 +0000[diff] [blame]642</dl>
Anton Korobeynikovd61d39e2006-09-14 18:23:27 +0000[diff] [blame]643
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]644<p>The next two types of linkage are targeted for Microsoft Windows platform
645 only. They are designed to support importing (exporting) symbols from (to)
646 DLLs (Dynamic Link Libraries).</p>
Anton Korobeynikovd61d39e2006-09-14 18:23:27 +0000[diff] [blame]647
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]648<dl>
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]649 <dt><tt><b><a name="linkage_dllimport">dllimport</a></b></tt></dt>
Anton Korobeynikovd61d39e2006-09-14 18:23:27 +0000[diff] [blame]650 <dd>"<tt>dllimport</tt>" linkage causes the compiler to reference a function
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]651 or variable via a global pointer to a pointer that is set up by the DLL
652 exporting the symbol. On Microsoft Windows targets, the pointer name is
653 formed by combining <code>__imp_</code> and the function or variable
654 name.</dd>
Anton Korobeynikovd61d39e2006-09-14 18:23:27 +0000[diff] [blame]655
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]656 <dt><tt><b><a name="linkage_dllexport">dllexport</a></b></tt></dt>
Anton Korobeynikovd61d39e2006-09-14 18:23:27 +0000[diff] [blame]657 <dd>"<tt>dllexport</tt>" linkage causes the compiler to provide a global
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]658 pointer to a pointer in a DLL, so that it can be referenced with the
659 <tt>dllimport</tt> attribute. On Microsoft Windows targets, the pointer
660 name is formed by combining <code>__imp_</code> and the function or
661 variable name.</dd>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]662</dl>
663
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]664<p>For example, since the "<tt>.LC0</tt>" variable is defined to be internal, if
665 another module defined a "<tt>.LC0</tt>" variable and was linked with this
666 one, one of the two would be renamed, preventing a collision. Since
667 "<tt>main</tt>" and "<tt>puts</tt>" are external (i.e., lacking any linkage
668 declarations), they are accessible outside of the current module.</p>
669
670<p>It is illegal for a function <i>declaration</i> to have any linkage type
671 other than "externally visible", <tt>dllimport</tt>
672 or <tt>extern_weak</tt>.</p>
673
Duncan Sands12da8ce2009-03-07 15:45:40 +0000[diff] [blame]674<p>Aliases can have only <tt>external</tt>, <tt>internal</tt>, <tt>weak</tt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]675 or <tt>weak_odr</tt> linkages.</p>
676
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]677</div>
678
679<!-- ======================================================================= -->
680<div class="doc_subsection">
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]681 <a name="callingconv">Calling Conventions</a>
682</div>
683
684<div class="doc_text">
685
686<p>LLVM <a href="#functionstructure">functions</a>, <a href="#i_call">calls</a>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]687 and <a href="#i_invoke">invokes</a> can all have an optional calling
688 convention specified for the call. The calling convention of any pair of
689 dynamic caller/callee must match, or the behavior of the program is
690 undefined. The following calling conventions are supported by LLVM, and more
691 may be added in the future:</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]692
693<dl>
694 <dt><b>"<tt>ccc</tt>" - The C calling convention</b>:</dt>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]695 <dd>This calling convention (the default if no other calling convention is
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]696 specified) matches the target C calling conventions. This calling
697 convention supports varargs function calls and tolerates some mismatch in
698 the declared prototype and implemented declaration of the function (as
699 does normal C).</dd>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]700
701 <dt><b>"<tt>fastcc</tt>" - The fast calling convention</b>:</dt>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]702 <dd>This calling convention attempts to make calls as fast as possible
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]703 (e.g. by passing things in registers). This calling convention allows the
704 target to use whatever tricks it wants to produce fast code for the
705 target, without having to conform to an externally specified ABI
Jeffrey Yasskinb8677462010-01-09 19:44:16 +0000[diff] [blame]706 (Application Binary Interface).
707 <a href="CodeGenerator.html#tailcallopt">Tail calls can only be optimized
Chris Lattnera179e4d2010-03-11 00:22:57 +0000[diff] [blame]708 when this or the GHC convention is used.</a> This calling convention
709 does not support varargs and requires the prototype of all callees to
710 exactly match the prototype of the function definition.</dd>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]711
712 <dt><b>"<tt>coldcc</tt>" - The cold calling convention</b>:</dt>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]713 <dd>This calling convention attempts to make code in the caller as efficient
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]714 as possible under the assumption that the call is not commonly executed.
715 As such, these calls often preserve all registers so that the call does
716 not break any live ranges in the caller side. This calling convention
717 does not support varargs and requires the prototype of all callees to
718 exactly match the prototype of the function definition.</dd>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]719
Chris Lattnera179e4d2010-03-11 00:22:57 +0000[diff] [blame]720 <dt><b>"<tt>cc <em>10</em></tt>" - GHC convention</b>:</dt>
721 <dd>This calling convention has been implemented specifically for use by the
722 <a href="http://www.haskell.org/ghc">Glasgow Haskell Compiler (GHC)</a>.
723 It passes everything in registers, going to extremes to achieve this by
724 disabling callee save registers. This calling convention should not be
725 used lightly but only for specific situations such as an alternative to
726 the <em>register pinning</em> performance technique often used when
727 implementing functional programming languages.At the moment only X86
728 supports this convention and it has the following limitations:
729 <ul>
730 <li>On <em>X86-32</em> only supports up to 4 bit type parameters. No
731 floating point types are supported.</li>
732 <li>On <em>X86-64</em> only supports up to 10 bit type parameters and
733 6 floating point parameters.</li>
734 </ul>
735 This calling convention supports
736 <a href="CodeGenerator.html#tailcallopt">tail call optimization</a> but
737 requires both the caller and callee are using it.
738 </dd>
739
Chris Lattner573f64e2005-05-07 01:46:40 +0000[diff] [blame]740 <dt><b>"<tt>cc &lt;<em>n</em>&gt;</tt>" - Numbered convention</b>:</dt>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]741 <dd>Any calling convention may be specified by number, allowing
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]742 target-specific calling conventions to be used. Target specific calling
743 conventions start at 64.</dd>
Chris Lattner573f64e2005-05-07 01:46:40 +0000[diff] [blame]744</dl>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]745
746<p>More calling conventions can be added/defined on an as-needed basis, to
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]747 support Pascal conventions or any other well-known target-independent
748 convention.</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]749
750</div>
751
752<!-- ======================================================================= -->
753<div class="doc_subsection">
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]754 <a name="visibility">Visibility Styles</a>
755</div>
756
757<div class="doc_text">
758
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]759<p>All Global Variables and Functions have one of the following visibility
760 styles:</p>
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]761
762<dl>
763 <dt><b>"<tt>default</tt>" - Default style</b>:</dt>
Chris Lattner67c37d12008-08-05 18:29:16 +0000[diff] [blame]764 <dd>On targets that use the ELF object file format, default visibility means
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]765 that the declaration is visible to other modules and, in shared libraries,
766 means that the declared entity may be overridden. On Darwin, default
767 visibility means that the declaration is visible to other modules. Default
768 visibility corresponds to "external linkage" in the language.</dd>
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]769
770 <dt><b>"<tt>hidden</tt>" - Hidden style</b>:</dt>
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]771 <dd>Two declarations of an object with hidden visibility refer to the same
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]772 object if they are in the same shared object. Usually, hidden visibility
773 indicates that the symbol will not be placed into the dynamic symbol
774 table, so no other module (executable or shared library) can reference it
775 directly.</dd>
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]776
Anton Korobeynikov39f3cff2007-04-29 18:35:00 +0000[diff] [blame]777 <dt><b>"<tt>protected</tt>" - Protected style</b>:</dt>
Anton Korobeynikov39f3cff2007-04-29 18:35:00 +0000[diff] [blame]778 <dd>On ELF, protected visibility indicates that the symbol will be placed in
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]779 the dynamic symbol table, but that references within the defining module
780 will bind to the local symbol. That is, the symbol cannot be overridden by
781 another module.</dd>
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]782</dl>
783
784</div>
785
786<!-- ======================================================================= -->
787<div class="doc_subsection">
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]788 <a name="namedtypes">Named Types</a>
789</div>
790
791<div class="doc_text">
792
793<p>LLVM IR allows you to specify name aliases for certain types. This can make
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]794 it easier to read the IR and make the IR more condensed (particularly when
795 recursive types are involved). An example of a name specification is:</p>
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]796
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]797<pre class="doc_code">
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]798%mytype = type { %mytype*, i32 }
799</pre>
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]800
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]801<p>You may give a name to any <a href="#typesystem">type</a> except
Chris Lattner249b9762010-08-17 23:26:04 +0000[diff] [blame]802 "<a href="#t_void">void</a>". Type name aliases may be used anywhere a type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]803 is expected with the syntax "%mytype".</p>
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]804
805<p>Note that type names are aliases for the structural type that they indicate,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]806 and that you can therefore specify multiple names for the same type. This
807 often leads to confusing behavior when dumping out a .ll file. Since LLVM IR
808 uses structural typing, the name is not part of the type. When printing out
809 LLVM IR, the printer will pick <em>one name</em> to render all types of a
810 particular shape. This means that if you have code where two different
811 source types end up having the same LLVM type, that the dumper will sometimes
812 print the "wrong" or unexpected type. This is an important design point and
813 isn't going to change.</p>
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]814
815</div>
816
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]817<!-- ======================================================================= -->
818<div class="doc_subsection">
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]819 <a name="globalvars">Global Variables</a>
820</div>
821
822<div class="doc_text">
823
Chris Lattner5d5aede2005-02-12 19:30:21 +0000[diff] [blame]824<p>Global variables define regions of memory allocated at compilation time
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]825 instead of run-time. Global variables may optionally be initialized, may
826 have an explicit section to be placed in, and may have an optional explicit
827 alignment specified. A variable may be defined as "thread_local", which
828 means that it will not be shared by threads (each thread will have a
829 separated copy of the variable). A variable may be defined as a global
830 "constant," which indicates that the contents of the variable
831 will <b>never</b> be modified (enabling better optimization, allowing the
832 global data to be placed in the read-only section of an executable, etc).
833 Note that variables that need runtime initialization cannot be marked
834 "constant" as there is a store to the variable.</p>
Chris Lattner5d5aede2005-02-12 19:30:21 +0000[diff] [blame]835
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]836<p>LLVM explicitly allows <em>declarations</em> of global variables to be marked
837 constant, even if the final definition of the global is not. This capability
838 can be used to enable slightly better optimization of the program, but
839 requires the language definition to guarantee that optimizations based on the
840 'constantness' are valid for the translation units that do not include the
841 definition.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]842
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]843<p>As SSA values, global variables define pointer values that are in scope
844 (i.e. they dominate) all basic blocks in the program. Global variables
845 always define a pointer to their "content" type because they describe a
846 region of memory, and all memory objects in LLVM are accessed through
847 pointers.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]848
Rafael Espindola45e6c192011-01-08 16:42:36 +0000[diff] [blame]849<p>Global variables can be marked with <tt>unnamed_addr</tt> which indicates
850 that the address is not significant, only the content. Constants marked
Rafael Espindolaf1ed7812011-01-15 08:20:57 +0000[diff] [blame]851 like this can be merged with other constants if they have the same
852 initializer. Note that a constant with significant address <em>can</em>
853 be merged with a <tt>unnamed_addr</tt> constant, the result being a
854 constant whose address is significant.</p>
Rafael Espindola45e6c192011-01-08 16:42:36 +0000[diff] [blame]855
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]856<p>A global variable may be declared to reside in a target-specific numbered
857 address space. For targets that support them, address spaces may affect how
858 optimizations are performed and/or what target instructions are used to
859 access the variable. The default address space is zero. The address space
860 qualifier must precede any other attributes.</p>
Christopher Lamb308121c2007-12-11 09:31:00 +0000[diff] [blame]861
Chris Lattner662c8722005-11-12 00:45:07 +0000[diff] [blame]862<p>LLVM allows an explicit section to be specified for globals. If the target
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]863 supports it, it will emit globals to the section specified.</p>
Chris Lattner662c8722005-11-12 00:45:07 +0000[diff] [blame]864
Chris Lattner78e00bc2010-04-28 00:13:42 +0000[diff] [blame]865<p>An explicit alignment may be specified for a global, which must be a power
866 of 2. If not present, or if the alignment is set to zero, the alignment of
867 the global is set by the target to whatever it feels convenient. If an
868 explicit alignment is specified, the global is forced to have exactly that
Chris Lattner4bd85e42010-04-28 00:31:12 +0000[diff] [blame]869 alignment. Targets and optimizers are not allowed to over-align the global
870 if the global has an assigned section. In this case, the extra alignment
871 could be observable: for example, code could assume that the globals are
872 densely packed in their section and try to iterate over them as an array,
873 alignment padding would break this iteration.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]874
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]875<p>For example, the following defines a global in a numbered address space with
876 an initializer, section, and alignment:</p>
Chris Lattner5760c502007-01-14 00:27:09 +0000[diff] [blame]877
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]878<pre class="doc_code">
Dan Gohmanaaa679b2009-01-11 00:40:00 +0000[diff] [blame]879@G = addrspace(5) constant float 1.0, section "foo", align 4
Chris Lattner5760c502007-01-14 00:27:09 +0000[diff] [blame]880</pre>
881
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]882</div>
883
884
885<!-- ======================================================================= -->
886<div class="doc_subsection">
887 <a name="functionstructure">Functions</a>
888</div>
889
890<div class="doc_text">
891
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]892<p>LLVM function definitions consist of the "<tt>define</tt>" keyword, an
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]893 optional <a href="#linkage">linkage type</a>, an optional
894 <a href="#visibility">visibility style</a>, an optional
Rafael Espindola45e6c192011-01-08 16:42:36 +0000[diff] [blame]895 <a href="#callingconv">calling convention</a>,
896 an optional <tt>unnamed_addr</tt> attribute, a return type, an optional
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]897 <a href="#paramattrs">parameter attribute</a> for the return type, a function
898 name, a (possibly empty) argument list (each with optional
899 <a href="#paramattrs">parameter attributes</a>), optional
900 <a href="#fnattrs">function attributes</a>, an optional section, an optional
901 alignment, an optional <a href="#gc">garbage collector name</a>, an opening
902 curly brace, a list of basic blocks, and a closing curly brace.</p>
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]903
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]904<p>LLVM function declarations consist of the "<tt>declare</tt>" keyword, an
905 optional <a href="#linkage">linkage type</a>, an optional
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]906 <a href="#visibility">visibility style</a>, an optional
Rafael Espindola45e6c192011-01-08 16:42:36 +0000[diff] [blame]907 <a href="#callingconv">calling convention</a>,
908 an optional <tt>unnamed_addr</tt> attribute, a return type, an optional
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]909 <a href="#paramattrs">parameter attribute</a> for the return type, a function
910 name, a possibly empty list of arguments, an optional alignment, and an
911 optional <a href="#gc">garbage collector name</a>.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]912
Chris Lattner67c37d12008-08-05 18:29:16 +0000[diff] [blame]913<p>A function definition contains a list of basic blocks, forming the CFG
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]914 (Control Flow Graph) for the function. Each basic block may optionally start
915 with a label (giving the basic block a symbol table entry), contains a list
916 of instructions, and ends with a <a href="#terminators">terminator</a>
917 instruction (such as a branch or function return).</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]918
Chris Lattnera59fb102007-06-08 16:52:14 +0000[diff] [blame]919<p>The first basic block in a function is special in two ways: it is immediately
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]920 executed on entrance to the function, and it is not allowed to have
921 predecessor basic blocks (i.e. there can not be any branches to the entry
922 block of a function). Because the block can have no predecessors, it also
923 cannot have any <a href="#i_phi">PHI nodes</a>.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]924
Chris Lattner662c8722005-11-12 00:45:07 +0000[diff] [blame]925<p>LLVM allows an explicit section to be specified for functions. If the target
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]926 supports it, it will emit functions to the section specified.</p>
Chris Lattner662c8722005-11-12 00:45:07 +0000[diff] [blame]927
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]928<p>An explicit alignment may be specified for a function. If not present, or if
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]929 the alignment is set to zero, the alignment of the function is set by the
930 target to whatever it feels convenient. If an explicit alignment is
931 specified, the function is forced to have at least that much alignment. All
932 alignments must be a power of 2.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]933
Rafael Espindola45e6c192011-01-08 16:42:36 +0000[diff] [blame]934<p>If the <tt>unnamed_addr</tt> attribute is given, the address is know to not
935 be significant and two identical functions can be merged</p>.
936
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]937<h5>Syntax:</h5>
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]938<pre class="doc_code">
Chris Lattner0ae02092008-10-13 16:55:18 +0000[diff] [blame]939define [<a href="#linkage">linkage</a>] [<a href="#visibility">visibility</a>]
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]940 [<a href="#callingconv">cconv</a>] [<a href="#paramattrs">ret attrs</a>]
941 &lt;ResultType&gt; @&lt;FunctionName&gt; ([argument list])
942 [<a href="#fnattrs">fn Attrs</a>] [section "name"] [align N]
943 [<a href="#gc">gc</a>] { ... }
944</pre>
Devang Patel02256232008-10-07 17:48:33 +0000[diff] [blame]945
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]946</div>
947
Anton Korobeynikova97b6942007-04-25 14:27:10 +0000[diff] [blame]948<!-- ======================================================================= -->
949<div class="doc_subsection">
950 <a name="aliasstructure">Aliases</a>
951</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]952
Anton Korobeynikova97b6942007-04-25 14:27:10 +0000[diff] [blame]953<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]954
955<p>Aliases act as "second name" for the aliasee value (which can be either
956 function, global variable, another alias or bitcast of global value). Aliases
957 may have an optional <a href="#linkage">linkage type</a>, and an
958 optional <a href="#visibility">visibility style</a>.</p>
Anton Korobeynikova97b6942007-04-25 14:27:10 +0000[diff] [blame]959
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]960<h5>Syntax:</h5>
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]961<pre class="doc_code">
Duncan Sands7e99a942008-09-12 20:48:21 +0000[diff] [blame]962@&lt;Name&gt; = alias [Linkage] [Visibility] &lt;AliaseeTy&gt; @&lt;Aliasee&gt;
Bill Wendling2d8b9a82007-05-29 09:42:13 +0000[diff] [blame]963</pre>
Anton Korobeynikova97b6942007-04-25 14:27:10 +0000[diff] [blame]964
965</div>
966
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]967<!-- ======================================================================= -->
Devang Pateld1a89692010-01-11 19:35:55 +0000[diff] [blame]968<div class="doc_subsection">
969 <a name="namedmetadatastructure">Named Metadata</a>
970</div>
971
972<div class="doc_text">
973
Chris Lattnerc2f8f162010-01-15 21:50:19 +0000[diff] [blame]974<p>Named metadata is a collection of metadata. <a href="#metadata">Metadata
Dan Gohman093cb792010-07-21 18:54:18 +0000[diff] [blame]975 nodes</a> (but not metadata strings) are the only valid operands for
Chris Lattnerc2f8f162010-01-15 21:50:19 +0000[diff] [blame]976 a named metadata.</p>
Devang Pateld1a89692010-01-11 19:35:55 +0000[diff] [blame]977
978<h5>Syntax:</h5>
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]979<pre class="doc_code">
Dan Gohman093cb792010-07-21 18:54:18 +0000[diff] [blame]980; Some unnamed metadata nodes, which are referenced by the named metadata.
981!0 = metadata !{metadata !"zero"}
Devang Pateld1a89692010-01-11 19:35:55 +0000[diff] [blame]982!1 = metadata !{metadata !"one"}
Dan Gohman093cb792010-07-21 18:54:18 +0000[diff] [blame]983!2 = metadata !{metadata !"two"}
Dan Gohman58cd65f2010-07-13 19:48:13 +0000[diff] [blame]984; A named metadata.
Dan Gohman093cb792010-07-21 18:54:18 +0000[diff] [blame]985!name = !{!0, !1, !2}
Devang Pateld1a89692010-01-11 19:35:55 +0000[diff] [blame]986</pre>
Devang Pateld1a89692010-01-11 19:35:55 +0000[diff] [blame]987
988</div>
989
990<!-- ======================================================================= -->
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]991<div class="doc_subsection"><a name="paramattrs">Parameter Attributes</a></div>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]992
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]993<div class="doc_text">
994
995<p>The return type and each parameter of a function type may have a set of
996 <i>parameter attributes</i> associated with them. Parameter attributes are
997 used to communicate additional information about the result or parameters of
998 a function. Parameter attributes are considered to be part of the function,
999 not of the function type, so functions with different parameter attributes
1000 can have the same function type.</p>
1001
1002<p>Parameter attributes are simple keywords that follow the type specified. If
1003 multiple parameter attributes are needed, they are space separated. For
1004 example:</p>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]1005
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]1006<pre class="doc_code">
Nick Lewyckydac78d82009-02-15 23:06:14 +0000[diff] [blame]1007declare i32 @printf(i8* noalias nocapture, ...)
Chris Lattnerd2597d72008-10-04 18:33:34 +0000[diff] [blame]1008declare i32 @atoi(i8 zeroext)
1009declare signext i8 @returns_signed_char()
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]1010</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]1011
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1012<p>Note that any attributes for the function result (<tt>nounwind</tt>,
1013 <tt>readonly</tt>) come immediately after the argument list.</p>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1014
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1015<p>Currently, only the following parameter attributes are defined:</p>
Chris Lattner5cee13f2008-01-11 06:20:47 +0000[diff] [blame]1016
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1017<dl>
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1018 <dt><tt><b>zeroext</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1019 <dd>This indicates to the code generator that the parameter or return value
Cameron Zwarichac106272011-03-16 22:20:18 +0000[diff] [blame]1020 should be zero-extended to the extent required by the target's ABI (which
1021 is usually 32-bits, but is 8-bits for a i1 on x86-64) by the caller (for a
1022 parameter) or the callee (for a return value).</dd>
Chris Lattner5cee13f2008-01-11 06:20:47 +0000[diff] [blame]1023
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1024 <dt><tt><b>signext</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1025 <dd>This indicates to the code generator that the parameter or return value
Cameron Zwarich341c36d2011-03-17 14:21:58 +0000[diff] [blame]1026 should be sign-extended to the extent required by the target's ABI (which
1027 is usually 32-bits) by the caller (for a parameter) or the callee (for a
1028 return value).</dd>
Chris Lattner5cee13f2008-01-11 06:20:47 +0000[diff] [blame]1029
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1030 <dt><tt><b>inreg</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1031 <dd>This indicates that this parameter or return value should be treated in a
1032 special target-dependent fashion during while emitting code for a function
1033 call or return (usually, by putting it in a register as opposed to memory,
1034 though some targets use it to distinguish between two different kinds of
1035 registers). Use of this attribute is target-specific.</dd>
Chris Lattner5cee13f2008-01-11 06:20:47 +0000[diff] [blame]1036
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1037 <dt><tt><b><a name="byval">byval</a></b></tt></dt>
Chris Lattnerd78dbee2010-11-20 23:49:06 +0000[diff] [blame]1038 <dd><p>This indicates that the pointer parameter should really be passed by
1039 value to the function. The attribute implies that a hidden copy of the
1040 pointee
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1041 is made between the caller and the callee, so the callee is unable to
1042 modify the value in the callee. This attribute is only valid on LLVM
1043 pointer arguments. It is generally used to pass structs and arrays by
1044 value, but is also valid on pointers to scalars. The copy is considered
1045 to belong to the caller not the callee (for example,
1046 <tt><a href="#readonly">readonly</a></tt> functions should not write to
1047 <tt>byval</tt> parameters). This is not a valid attribute for return
Chris Lattnerd78dbee2010-11-20 23:49:06 +0000[diff] [blame]1048 values.</p>
1049
1050 <p>The byval attribute also supports specifying an alignment with
1051 the align attribute. It indicates the alignment of the stack slot to
1052 form and the known alignment of the pointer specified to the call site. If
1053 the alignment is not specified, then the code generator makes a
1054 target-specific assumption.</p></dd>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1055
Dan Gohman3770af52010-07-02 23:18:08 +0000[diff] [blame]1056 <dt><tt><b><a name="sret">sret</a></b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1057 <dd>This indicates that the pointer parameter specifies the address of a
1058 structure that is the return value of the function in the source program.
1059 This pointer must be guaranteed by the caller to be valid: loads and
1060 stores to the structure may be assumed by the callee to not to trap. This
1061 may only be applied to the first parameter. This is not a valid attribute
1062 for return values. </dd>
1063
Dan Gohman3770af52010-07-02 23:18:08 +0000[diff] [blame]1064 <dt><tt><b><a name="noalias">noalias</a></b></tt></dt>
Dan Gohmandf12d082010-07-02 18:41:32 +0000[diff] [blame]1065 <dd>This indicates that pointer values
1066 <a href="#pointeraliasing"><i>based</i></a> on the argument or return
Dan Gohmande256292010-07-02 23:46:54 +0000[diff] [blame]1067 value do not alias pointer values which are not <i>based</i> on it,
1068 ignoring certain "irrelevant" dependencies.
1069 For a call to the parent function, dependencies between memory
1070 references from before or after the call and from those during the call
1071 are "irrelevant" to the <tt>noalias</tt> keyword for the arguments and
1072 return value used in that call.
Dan Gohmandf12d082010-07-02 18:41:32 +0000[diff] [blame]1073 The caller shares the responsibility with the callee for ensuring that
1074 these requirements are met.
1075 For further details, please see the discussion of the NoAlias response in
Dan Gohman6c858db2010-07-06 15:26:33 +0000[diff] [blame]1076 <a href="AliasAnalysis.html#MustMayNo">alias analysis</a>.<br>
1077<br>
John McCall72ed8902010-07-06 21:07:14 +0000[diff] [blame]1078 Note that this definition of <tt>noalias</tt> is intentionally
1079 similar to the definition of <tt>restrict</tt> in C99 for function
Chris Lattner5eff9ca2010-07-06 20:51:35 +0000[diff] [blame]1080 arguments, though it is slightly weaker.
Dan Gohman6c858db2010-07-06 15:26:33 +0000[diff] [blame]1081<br>
1082 For function return values, C99's <tt>restrict</tt> is not meaningful,
1083 while LLVM's <tt>noalias</tt> is.
1084 </dd>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1085
Dan Gohman3770af52010-07-02 23:18:08 +0000[diff] [blame]1086 <dt><tt><b><a name="nocapture">nocapture</a></b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1087 <dd>This indicates that the callee does not make any copies of the pointer
1088 that outlive the callee itself. This is not a valid attribute for return
1089 values.</dd>
1090
Dan Gohman3770af52010-07-02 23:18:08 +0000[diff] [blame]1091 <dt><tt><b><a name="nest">nest</a></b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1092 <dd>This indicates that the pointer parameter can be excised using the
1093 <a href="#int_trampoline">trampoline intrinsics</a>. This is not a valid
1094 attribute for return values.</dd>
1095</dl>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1096
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1097</div>
1098
1099<!-- ======================================================================= -->
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]1100<div class="doc_subsection">
Gordon Henriksen71183b62007-12-10 03:18:06 +0000[diff] [blame]1101 <a name="gc">Garbage Collector Names</a>
1102</div>
1103
1104<div class="doc_text">
Gordon Henriksen71183b62007-12-10 03:18:06 +0000[diff] [blame]1105
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1106<p>Each function may specify a garbage collector name, which is simply a
1107 string:</p>
1108
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]1109<pre class="doc_code">
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1110define void @f() gc "name" { ... }
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1111</pre>
Gordon Henriksen71183b62007-12-10 03:18:06 +0000[diff] [blame]1112
1113<p>The compiler declares the supported values of <i>name</i>. Specifying a
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1114 collector which will cause the compiler to alter its output in order to
1115 support the named garbage collection algorithm.</p>
1116
Gordon Henriksen71183b62007-12-10 03:18:06 +0000[diff] [blame]1117</div>
1118
1119<!-- ======================================================================= -->
1120<div class="doc_subsection">
Devang Patel9eb525d2008-09-26 23:51:19 +0000[diff] [blame]1121 <a name="fnattrs">Function Attributes</a>
Devang Patelcaacdba2008-09-04 23:05:13 +0000[diff] [blame]1122</div>
1123
1124<div class="doc_text">
Devang Patel9eb525d2008-09-26 23:51:19 +0000[diff] [blame]1125
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1126<p>Function attributes are set to communicate additional information about a
1127 function. Function attributes are considered to be part of the function, not
1128 of the function type, so functions with different parameter attributes can
1129 have the same function type.</p>
Devang Patel9eb525d2008-09-26 23:51:19 +0000[diff] [blame]1130
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1131<p>Function attributes are simple keywords that follow the type specified. If
1132 multiple attributes are needed, they are space separated. For example:</p>
Devang Patelcaacdba2008-09-04 23:05:13 +0000[diff] [blame]1133
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]1134<pre class="doc_code">
Devang Patel9eb525d2008-09-26 23:51:19 +0000[diff] [blame]1135define void @f() noinline { ... }
1136define void @f() alwaysinline { ... }
1137define void @f() alwaysinline optsize { ... }
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1138define void @f() optsize { ... }
Bill Wendlingb175fa42008-09-07 10:26:33 +0000[diff] [blame]1139</pre>
Devang Patelcaacdba2008-09-04 23:05:13 +0000[diff] [blame]1140
Bill Wendlingb175fa42008-09-07 10:26:33 +0000[diff] [blame]1141<dl>
Charles Davisbe5557e2010-02-12 00:31:15 +0000[diff] [blame]1142 <dt><tt><b>alignstack(&lt;<em>n</em>&gt;)</b></tt></dt>
1143 <dd>This attribute indicates that, when emitting the prologue and epilogue,
1144 the backend should forcibly align the stack pointer. Specify the
1145 desired alignment, which must be a power of two, in parentheses.
1146
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1147 <dt><tt><b>alwaysinline</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1148 <dd>This attribute indicates that the inliner should attempt to inline this
1149 function into callers whenever possible, ignoring any active inlining size
1150 threshold for this caller.</dd>
Bill Wendlingb175fa42008-09-07 10:26:33 +0000[diff] [blame]1151
Charles Davis22fe1862010-10-25 15:37:09 +0000[diff] [blame]1152 <dt><tt><b>hotpatch</b></tt></dt>
Charles Davis1b2d3722010-10-25 16:29:03 +0000[diff] [blame]1153 <dd>This attribute indicates that the function should be 'hotpatchable',
Charles Davis74205252010-10-25 19:07:39 +0000[diff] [blame]1154 meaning the function can be patched and/or hooked even while it is
1155 loaded into memory. On x86, the function prologue will be preceded
1156 by six bytes of padding and will begin with a two-byte instruction.
1157 Most of the functions in the Windows system DLLs in Windows XP SP2 or
1158 higher were compiled in this fashion.</dd>
Charles Davis22fe1862010-10-25 15:37:09 +0000[diff] [blame]1159
Jakob Stoklund Olesen74bb06c2010-02-06 01:16:28 +0000[diff] [blame]1160 <dt><tt><b>inlinehint</b></tt></dt>
1161 <dd>This attribute indicates that the source code contained a hint that inlining
1162 this function is desirable (such as the "inline" keyword in C/C++). It
1163 is just a hint; it imposes no requirements on the inliner.</dd>
1164
Nick Lewycky14b58da2010-07-06 18:24:09 +0000[diff] [blame]1165 <dt><tt><b>naked</b></tt></dt>
1166 <dd>This attribute disables prologue / epilogue emission for the function.
1167 This can have very system-specific consequences.</dd>
1168
1169 <dt><tt><b>noimplicitfloat</b></tt></dt>
1170 <dd>This attributes disables implicit floating point instructions.</dd>
1171
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1172 <dt><tt><b>noinline</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1173 <dd>This attribute indicates that the inliner should never inline this
1174 function in any situation. This attribute may not be used together with
1175 the <tt>alwaysinline</tt> attribute.</dd>
Devang Patel9eb525d2008-09-26 23:51:19 +0000[diff] [blame]1176
Nick Lewycky14b58da2010-07-06 18:24:09 +0000[diff] [blame]1177 <dt><tt><b>noredzone</b></tt></dt>
1178 <dd>This attribute indicates that the code generator should not use a red
1179 zone, even if the target-specific ABI normally permits it.</dd>
Devang Patel9eb525d2008-09-26 23:51:19 +0000[diff] [blame]1180
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1181 <dt><tt><b>noreturn</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1182 <dd>This function attribute indicates that the function never returns
1183 normally. This produces undefined behavior at runtime if the function
1184 ever does dynamically return.</dd>
Bill Wendlinga8130172008-11-13 01:02:51 +0000[diff] [blame]1185
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1186 <dt><tt><b>nounwind</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1187 <dd>This function attribute indicates that the function never returns with an
1188 unwind or exceptional control flow. If the function does unwind, its
1189 runtime behavior is undefined.</dd>
Bill Wendling0f5541e2008-11-26 19:07:40 +0000[diff] [blame]1190
Nick Lewycky14b58da2010-07-06 18:24:09 +0000[diff] [blame]1191 <dt><tt><b>optsize</b></tt></dt>
1192 <dd>This attribute suggests that optimization passes and code generator passes
1193 make choices that keep the code size of this function low, and otherwise
1194 do optimizations specifically to reduce code size.</dd>
1195
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1196 <dt><tt><b>readnone</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1197 <dd>This attribute indicates that the function computes its result (or decides
1198 to unwind an exception) based strictly on its arguments, without
1199 dereferencing any pointer arguments or otherwise accessing any mutable
1200 state (e.g. memory, control registers, etc) visible to caller functions.
1201 It does not write through any pointer arguments
1202 (including <tt><a href="#byval">byval</a></tt> arguments) and never
1203 changes any state visible to callers. This means that it cannot unwind
1204 exceptions by calling the <tt>C++</tt> exception throwing methods, but
1205 could use the <tt>unwind</tt> instruction.</dd>
Devang Patel310fd4a2009-06-12 19:45:19 +0000[diff] [blame]1206
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1207 <dt><tt><b><a name="readonly">readonly</a></b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1208 <dd>This attribute indicates that the function does not write through any
1209 pointer arguments (including <tt><a href="#byval">byval</a></tt>
1210 arguments) or otherwise modify any state (e.g. memory, control registers,
1211 etc) visible to caller functions. It may dereference pointer arguments
1212 and read state that may be set in the caller. A readonly function always
1213 returns the same value (or unwinds an exception identically) when called
1214 with the same set of arguments and global state. It cannot unwind an
1215 exception by calling the <tt>C++</tt> exception throwing methods, but may
1216 use the <tt>unwind</tt> instruction.</dd>
Anton Korobeynikovc8ce7b082009-07-17 18:07:26 +0000[diff] [blame]1217
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1218 <dt><tt><b><a name="ssp">ssp</a></b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1219 <dd>This attribute indicates that the function should emit a stack smashing
1220 protector. It is in the form of a "canary"&mdash;a random value placed on
1221 the stack before the local variables that's checked upon return from the
1222 function to see if it has been overwritten. A heuristic is used to
1223 determine if a function needs stack protectors or not.<br>
1224<br>
1225 If a function that has an <tt>ssp</tt> attribute is inlined into a
1226 function that doesn't have an <tt>ssp</tt> attribute, then the resulting
1227 function will have an <tt>ssp</tt> attribute.</dd>
1228
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1229 <dt><tt><b>sspreq</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1230 <dd>This attribute indicates that the function should <em>always</em> emit a
1231 stack smashing protector. This overrides
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1232 the <tt><a href="#ssp">ssp</a></tt> function attribute.<br>
1233<br>
1234 If a function that has an <tt>sspreq</tt> attribute is inlined into a
1235 function that doesn't have an <tt>sspreq</tt> attribute or which has
1236 an <tt>ssp</tt> attribute, then the resulting function will have
1237 an <tt>sspreq</tt> attribute.</dd>
Bill Wendlingb175fa42008-09-07 10:26:33 +0000[diff] [blame]1238</dl>
1239
Devang Patelcaacdba2008-09-04 23:05:13 +0000[diff] [blame]1240</div>
1241
1242<!-- ======================================================================= -->
1243<div class="doc_subsection">
Chris Lattner93564892006-04-08 04:40:53 +0000[diff] [blame]1244 <a name="moduleasm">Module-Level Inline Assembly</a>
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]1245</div>
1246
1247<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1248
1249<p>Modules may contain "module-level inline asm" blocks, which corresponds to
1250 the GCC "file scope inline asm" blocks. These blocks are internally
1251 concatenated by LLVM and treated as a single unit, but may be separated in
1252 the <tt>.ll</tt> file if desired. The syntax is very simple:</p>
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]1253
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]1254<pre class="doc_code">
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]1255module asm "inline asm code goes here"
1256module asm "more can go here"
1257</pre>
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]1258
1259<p>The strings can contain any character by escaping non-printable characters.
1260 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]1261 for the number.</p>
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]1262
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1263<p>The inline asm code is simply printed to the machine code .s file when
1264 assembly code is generated.</p>
1265
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]1266</div>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]1267
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1268<!-- ======================================================================= -->
1269<div class="doc_subsection">
1270 <a name="datalayout">Data Layout</a>
1271</div>
1272
1273<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1274
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1275<p>A module may specify a target specific data layout string that specifies how
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1276 data is to be laid out in memory. The syntax for the data layout is
1277 simply:</p>
1278
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]1279<pre class="doc_code">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1280target datalayout = "<i>layout specification</i>"
1281</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1282
1283<p>The <i>layout specification</i> consists of a list of specifications
1284 separated by the minus sign character ('-'). Each specification starts with
1285 a letter and may include other information after the letter to define some
1286 aspect of the data layout. The specifications accepted are as follows:</p>
1287
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1288<dl>
1289 <dt><tt>E</tt></dt>
1290 <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]1291 bits with the most significance have the lowest address location.</dd>
1292
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1293 <dt><tt>e</tt></dt>
Chris Lattner67c37d12008-08-05 18:29:16 +0000[diff] [blame]1294 <dd>Specifies that the target lays out data in little-endian form. That is,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1295 the bits with the least significance have the lowest address
1296 location.</dd>
1297
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1298 <dt><tt>p:<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]1299 <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]1300 <i>preferred</i> alignments. All sizes are in bits. Specifying
1301 the <i>pref</i> alignment is optional. If omitted, the
1302 preceding <tt>:</tt> should be omitted too.</dd>
1303
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1304 <dt><tt>i<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1305 <dd>This specifies the alignment for an integer type of a given bit
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1306 <i>size</i>. The value of <i>size</i> must be in the range [1,2^23).</dd>
1307
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1308 <dt><tt>v<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]1309 <dd>This specifies the alignment for a vector type of a given bit
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1310 <i>size</i>.</dd>
1311
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1312 <dt><tt>f<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]1313 <dd>This specifies the alignment for a floating point type of a given bit
Dale Johannesence522852010-05-28 18:54:47 +0000[diff] [blame]1314 <i>size</i>. Only values of <i>size</i> that are supported by the target
1315 will work. 32 (float) and 64 (double) are supported on all targets;
1316 80 or 128 (different flavors of long double) are also supported on some
1317 targets.
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1318
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1319 <dt><tt>a<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1320 <dd>This specifies the alignment for an aggregate type of a given bit
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1321 <i>size</i>.</dd>
1322
Daniel Dunbar7921a592009-06-08 22:17:53 +0000[diff] [blame]1323 <dt><tt>s<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1324 <dd>This specifies the alignment for a stack object of a given bit
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1325 <i>size</i>.</dd>
Chris Lattnera381eff2009-11-07 09:35:34 +0000[diff] [blame]1326
1327 <dt><tt>n<i>size1</i>:<i>size2</i>:<i>size3</i>...</tt></dt>
1328 <dd>This specifies a set of native integer widths for the target CPU
1329 in bits. For example, it might contain "n32" for 32-bit PowerPC,
1330 "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]1331 this set are considered to support most general arithmetic
Chris Lattnera381eff2009-11-07 09:35:34 +0000[diff] [blame]1332 operations efficiently.</dd>
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1333</dl>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1334
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1335<p>When constructing the data layout for a given target, LLVM starts with a
Dan Gohman61110ae2010-04-28 00:36:01 +0000[diff] [blame]1336 default set of specifications which are then (possibly) overridden by the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1337 specifications in the <tt>datalayout</tt> keyword. The default specifications
1338 are given in this list:</p>
1339
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1340<ul>
1341 <li><tt>E</tt> - big endian</li>
Dan Gohman8ad777d2010-02-23 02:44:03 +0000[diff] [blame]1342 <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]1343 <li><tt>i1:8:8</tt> - i1 is 8-bit (byte) aligned</li>
1344 <li><tt>i8:8:8</tt> - i8 is 8-bit (byte) aligned</li>
1345 <li><tt>i16:16:16</tt> - i16 is 16-bit aligned</li>
1346 <li><tt>i32:32:32</tt> - i32 is 32-bit aligned</li>
Chris Lattner67c37d12008-08-05 18:29:16 +0000[diff] [blame]1347 <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]1348 alignment of 64-bits</li>
1349 <li><tt>f32:32:32</tt> - float is 32-bit aligned</li>
1350 <li><tt>f64:64:64</tt> - double is 64-bit aligned</li>
1351 <li><tt>v64:64:64</tt> - 64-bit vector is 64-bit aligned</li>
1352 <li><tt>v128:128:128</tt> - 128-bit vector is 128-bit aligned</li>
1353 <li><tt>a0:0:1</tt> - aggregates are 8-bit aligned</li>
Daniel Dunbar7921a592009-06-08 22:17:53 +0000[diff] [blame]1354 <li><tt>s0:64:64</tt> - stack objects are 64-bit aligned</li>
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1355</ul>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1356
1357<p>When LLVM is determining the alignment for a given type, it uses the
1358 following rules:</p>
1359
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1360<ol>
1361 <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]1362 specification is used.</li>
1363
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1364 <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]1365 smallest integer type that is larger than the bitwidth of the sought type
1366 is used. If none of the specifications are larger than the bitwidth then
1367 the the largest integer type is used. For example, given the default
1368 specifications above, the i7 type will use the alignment of i8 (next
1369 largest) while both i65 and i256 will use the alignment of i64 (largest
1370 specified).</li>
1371
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1372 <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]1373 largest vector type that is smaller than the sought vector type will be
1374 used as a fall back. This happens because &lt;128 x double&gt; can be
1375 implemented in terms of 64 &lt;2 x double&gt;, for example.</li>
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1376</ol>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1377
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1378</div>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]1379
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1380<!-- ======================================================================= -->
1381<div class="doc_subsection">
1382 <a name="pointeraliasing">Pointer Aliasing Rules</a>
1383</div>
1384
1385<div class="doc_text">
1386
Andreas Bolka8ae4e242009-07-29 00:02:05 +0000[diff] [blame]1387<p>Any memory access must be done through a pointer value associated
Andreas Bolkae39f0332009-07-27 20:37:10 +0000[diff] [blame]1388with an address range of the memory access, otherwise the behavior
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1389is undefined. Pointer values are associated with address ranges
1390according to the following rules:</p>
1391
1392<ul>
Dan Gohmandf12d082010-07-02 18:41:32 +0000[diff] [blame]1393 <li>A pointer value is associated with the addresses associated with
1394 any value it is <i>based</i> on.
Andreas Bolka8ae4e242009-07-29 00:02:05 +0000[diff] [blame]1395 <li>An address of a global variable is associated with the address
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1396 range of the variable's storage.</li>
1397 <li>The result value of an allocation instruction is associated with
1398 the address range of the allocated storage.</li>
1399 <li>A null pointer in the default address-space is associated with
Andreas Bolka8ae4e242009-07-29 00:02:05 +0000[diff] [blame]1400 no address.</li>
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1401 <li>An integer constant other than zero or a pointer value returned
1402 from a function not defined within LLVM may be associated with address
1403 ranges allocated through mechanisms other than those provided by
Andreas Bolka8ae4e242009-07-29 00:02:05 +0000[diff] [blame]1404 LLVM. Such ranges shall not overlap with any ranges of addresses
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1405 allocated by mechanisms provided by LLVM.</li>
Dan Gohmandf12d082010-07-02 18:41:32 +0000[diff] [blame]1406</ul>
1407
1408<p>A pointer value is <i>based</i> on another pointer value according
1409 to the following rules:</p>
1410
1411<ul>
1412 <li>A pointer value formed from a
1413 <tt><a href="#i_getelementptr">getelementptr</a></tt> operation
1414 is <i>based</i> on the first operand of the <tt>getelementptr</tt>.</li>
1415 <li>The result value of a
1416 <tt><a href="#i_bitcast">bitcast</a></tt> is <i>based</i> on the operand
1417 of the <tt>bitcast</tt>.</li>
1418 <li>A pointer value formed by an
1419 <tt><a href="#i_inttoptr">inttoptr</a></tt> is <i>based</i> on all
1420 pointer values that contribute (directly or indirectly) to the
1421 computation of the pointer's value.</li>
1422 <li>The "<i>based</i> on" relationship is transitive.</li>
1423</ul>
1424
1425<p>Note that this definition of <i>"based"</i> is intentionally
1426 similar to the definition of <i>"based"</i> in C99, though it is
1427 slightly weaker.</p>
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1428
1429<p>LLVM IR does not associate types with memory. The result type of a
Andreas Bolka8ae4e242009-07-29 00:02:05 +0000[diff] [blame]1430<tt><a href="#i_load">load</a></tt> merely indicates the size and
1431alignment of the memory from which to load, as well as the
Dan Gohman4eb47192010-06-17 19:23:50 +0000[diff] [blame]1432interpretation of the value. The first operand type of a
Andreas Bolka8ae4e242009-07-29 00:02:05 +0000[diff] [blame]1433<tt><a href="#i_store">store</a></tt> similarly only indicates the size
1434and alignment of the store.</p>
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1435
1436<p>Consequently, type-based alias analysis, aka TBAA, aka
1437<tt>-fstrict-aliasing</tt>, is not applicable to general unadorned
1438LLVM IR. <a href="#metadata">Metadata</a> may be used to encode
1439additional information which specialized optimization passes may use
1440to implement type-based alias analysis.</p>
1441
1442</div>
1443
Jeffrey Yasskin5d284ae2010-04-26 21:21:24 +0000[diff] [blame]1444<!-- ======================================================================= -->
1445<div class="doc_subsection">
1446 <a name="volatile">Volatile Memory Accesses</a>
1447</div>
1448
1449<div class="doc_text">
1450
1451<p>Certain memory accesses, such as <a href="#i_load"><tt>load</tt></a>s, <a
1452href="#i_store"><tt>store</tt></a>s, and <a
1453href="#int_memcpy"><tt>llvm.memcpy</tt></a>s may be marked <tt>volatile</tt>.
1454The optimizers must not change the number of volatile operations or change their
1455order of execution relative to other volatile operations. The optimizers
1456<i>may</i> change the order of volatile operations relative to non-volatile
1457operations. This is not Java's "volatile" and has no cross-thread
1458synchronization behavior.</p>
1459
1460</div>
1461
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1462<!-- *********************************************************************** -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1463<div class="doc_section"> <a name="typesystem">Type System</a> </div>
1464<!-- *********************************************************************** -->
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]1465
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1466<div class="doc_text">
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]1467
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1468<p>The LLVM type system is one of the most important features of the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1469 intermediate representation. Being typed enables a number of optimizations
1470 to be performed on the intermediate representation directly, without having
1471 to do extra analyses on the side before the transformation. A strong type
1472 system makes it easier to read the generated code and enables novel analyses
1473 and transformations that are not feasible to perform on normal three address
1474 code representations.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]1475
1476</div>
1477
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1478<!-- ======================================================================= -->
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1479<div class="doc_subsection"> <a name="t_classifications">Type
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1480Classifications</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1481
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1482<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1483
1484<p>The types fall into a few useful classifications:</p>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]1485
1486<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1487 <tbody>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1488 <tr><th>Classification</th><th>Types</th></tr>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1489 <tr>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1490 <td><a href="#t_integer">integer</a></td>
Reid Spencer138249b2007-05-16 18:44:01 +0000[diff] [blame]1491 <td><tt>i1, i2, i3, ... i8, ... i16, ... i32, ... i64, ... </tt></td>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1492 </tr>
1493 <tr>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1494 <td><a href="#t_floating">floating point</a></td>
1495 <td><tt>float, double, x86_fp80, fp128, ppc_fp128</tt></td>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1496 </tr>
1497 <tr>
1498 <td><a name="t_firstclass">first class</a></td>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1499 <td><a href="#t_integer">integer</a>,
1500 <a href="#t_floating">floating point</a>,
1501 <a href="#t_pointer">pointer</a>,
Dan Gohman08783a882008-06-18 18:42:13 +0000[diff] [blame]1502 <a href="#t_vector">vector</a>,
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]1503 <a href="#t_struct">structure</a>,
1504 <a href="#t_array">array</a>,
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1505 <a href="#t_label">label</a>,
1506 <a href="#t_metadata">metadata</a>.
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1507 </td>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1508 </tr>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1509 <tr>
1510 <td><a href="#t_primitive">primitive</a></td>
1511 <td><a href="#t_label">label</a>,
1512 <a href="#t_void">void</a>,
Tobias Grosser4c8c95b2010-12-28 20:29:31 +0000[diff] [blame]1513 <a href="#t_integer">integer</a>,
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1514 <a href="#t_floating">floating point</a>,
Dale Johannesen33e5c352010-10-01 00:48:59 +0000[diff] [blame]1515 <a href="#t_x86mmx">x86mmx</a>,
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1516 <a href="#t_metadata">metadata</a>.</td>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1517 </tr>
1518 <tr>
1519 <td><a href="#t_derived">derived</a></td>
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]1520 <td><a href="#t_array">array</a>,
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1521 <a href="#t_function">function</a>,
1522 <a href="#t_pointer">pointer</a>,
1523 <a href="#t_struct">structure</a>,
1524 <a href="#t_pstruct">packed structure</a>,
1525 <a href="#t_vector">vector</a>,
1526 <a href="#t_opaque">opaque</a>.
Dan Gohman93bf60d2008-10-14 16:32:04 +0000[diff] [blame]1527 </td>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1528 </tr>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1529 </tbody>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1530</table>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]1531
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1532<p>The <a href="#t_firstclass">first class</a> types are perhaps the most
1533 important. Values of these types are the only ones which can be produced by
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]1534 instructions.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1535
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1536</div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1537
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1538<!-- ======================================================================= -->
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1539<div class="doc_subsection"> <a name="t_primitive">Primitive Types</a> </div>
Chris Lattner43542b32008-01-04 04:34:14 +0000[diff] [blame]1540
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1541<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1542
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1543<p>The primitive types are the fundamental building blocks of the LLVM
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1544 system.</p>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1545
Chris Lattner43542b32008-01-04 04:34:14 +0000[diff] [blame]1546</div>
1547
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1548<!-- _______________________________________________________________________ -->
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]1549<div class="doc_subsubsection"> <a name="t_integer">Integer Type</a> </div>
1550
1551<div class="doc_text">
1552
1553<h5>Overview:</h5>
1554<p>The integer type is a very simple type that simply specifies an arbitrary
1555 bit width for the integer type desired. Any bit width from 1 bit to
1556 2<sup>23</sup>-1 (about 8 million) can be specified.</p>
1557
1558<h5>Syntax:</h5>
1559<pre>
1560 iN
1561</pre>
1562
1563<p>The number of bits the integer will occupy is specified by the <tt>N</tt>
1564 value.</p>
1565
1566<h5>Examples:</h5>
1567<table class="layout">
1568 <tr class="layout">
1569 <td class="left"><tt>i1</tt></td>
1570 <td class="left">a single-bit integer.</td>
1571 </tr>
1572 <tr class="layout">
1573 <td class="left"><tt>i32</tt></td>
1574 <td class="left">a 32-bit integer.</td>
1575 </tr>
1576 <tr class="layout">
1577 <td class="left"><tt>i1942652</tt></td>
1578 <td class="left">a really big integer of over 1 million bits.</td>
1579 </tr>
1580</table>
1581
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]1582</div>
1583
1584<!-- _______________________________________________________________________ -->
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1585<div class="doc_subsubsection"> <a name="t_floating">Floating Point Types</a> </div>
1586
1587<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1588
1589<table>
1590 <tbody>
1591 <tr><th>Type</th><th>Description</th></tr>
1592 <tr><td><tt>float</tt></td><td>32-bit floating point value</td></tr>
1593 <tr><td><tt>double</tt></td><td>64-bit floating point value</td></tr>
1594 <tr><td><tt>fp128</tt></td><td>128-bit floating point value (112-bit mantissa)</td></tr>
1595 <tr><td><tt>x86_fp80</tt></td><td>80-bit floating point value (X87)</td></tr>
1596 <tr><td><tt>ppc_fp128</tt></td><td>128-bit floating point value (two 64-bits)</td></tr>
1597 </tbody>
1598</table>
1599
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1600</div>
1601
1602<!-- _______________________________________________________________________ -->
Dale Johannesen33e5c352010-10-01 00:48:59 +0000[diff] [blame]1603<div class="doc_subsubsection"> <a name="t_x86mmx">X86mmx Type</a> </div>
1604
1605<div class="doc_text">
1606
1607<h5>Overview:</h5>
1608<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>
1609
1610<h5>Syntax:</h5>
1611<pre>
Dale Johannesenb1f0ff12010-10-01 01:07:02 +0000[diff] [blame]1612 x86mmx
Dale Johannesen33e5c352010-10-01 00:48:59 +0000[diff] [blame]1613</pre>
1614
1615</div>
1616
1617<!-- _______________________________________________________________________ -->
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1618<div class="doc_subsubsection"> <a name="t_void">Void Type</a> </div>
1619
1620<div class="doc_text">
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1621
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1622<h5>Overview:</h5>
1623<p>The void type does not represent any value and has no size.</p>
1624
1625<h5>Syntax:</h5>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1626<pre>
1627 void
1628</pre>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1629
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1630</div>
1631
1632<!-- _______________________________________________________________________ -->
1633<div class="doc_subsubsection"> <a name="t_label">Label Type</a> </div>
1634
1635<div class="doc_text">
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1636
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1637<h5>Overview:</h5>
1638<p>The label type represents code labels.</p>
1639
1640<h5>Syntax:</h5>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1641<pre>
1642 label
1643</pre>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1644
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1645</div>
1646
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1647<!-- _______________________________________________________________________ -->
1648<div class="doc_subsubsection"> <a name="t_metadata">Metadata Type</a> </div>
1649
1650<div class="doc_text">
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1651
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1652<h5>Overview:</h5>
Nick Lewycky93e06a52009-09-27 23:27:42 +0000[diff] [blame]1653<p>The metadata type represents embedded metadata. No derived types may be
1654 created from metadata except for <a href="#t_function">function</a>
1655 arguments.
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1656
1657<h5>Syntax:</h5>
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1658<pre>
1659 metadata
1660</pre>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1661
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1662</div>
1663
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1664
1665<!-- ======================================================================= -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1666<div class="doc_subsection"> <a name="t_derived">Derived Types</a> </div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1667
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1668<div class="doc_text">
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1669
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1670<p>The real power in LLVM comes from the derived types in the system. This is
1671 what allows a programmer to represent arrays, functions, pointers, and other
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]1672 useful types. Each of these types contain one or more element types which
1673 may be a primitive type, or another derived type. For example, it is
1674 possible to have a two dimensional array, using an array as the element type
1675 of another array.</p>
Dan Gohman142ccc02009-01-24 15:58:40 +0000[diff] [blame]1676
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]1677
1678</div>
1679
1680<!-- _______________________________________________________________________ -->
1681<div class="doc_subsubsection"> <a name="t_aggregate">Aggregate Types</a> </div>
1682
1683<div class="doc_text">
1684
1685<p>Aggregate Types are a subset of derived types that can contain multiple
1686 member types. <a href="#t_array">Arrays</a>,
Chris Lattner13ee7952010-08-28 04:09:24 +0000[diff] [blame]1687 <a href="#t_struct">structs</a>, and <a href="#t_vector">vectors</a> are
1688 aggregate types.</p>
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]1689
1690</div>
1691
Reid Spencer138249b2007-05-16 18:44:01 +0000[diff] [blame]1692<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1693<div class="doc_subsubsection"> <a name="t_array">Array Type</a> </div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1694
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1695<div class="doc_text">
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1696
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1697<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1698<p>The array type is a very simple derived type that arranges elements
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1699 sequentially in memory. The array type requires a size (number of elements)
1700 and an underlying data type.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1701
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]1702<h5>Syntax:</h5>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1703<pre>
1704 [&lt;# elements&gt; x &lt;elementtype&gt;]
1705</pre>
1706
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1707<p>The number of elements is a constant integer value; <tt>elementtype</tt> may
1708 be any type with a size.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1709
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]1710<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1711<table class="layout">
1712 <tr class="layout">
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]1713 <td class="left"><tt>[40 x i32]</tt></td>
1714 <td class="left">Array of 40 32-bit integer values.</td>
1715 </tr>
1716 <tr class="layout">
1717 <td class="left"><tt>[41 x i32]</tt></td>
1718 <td class="left">Array of 41 32-bit integer values.</td>
1719 </tr>
1720 <tr class="layout">
1721 <td class="left"><tt>[4 x i8]</tt></td>
1722 <td class="left">Array of 4 8-bit integer values.</td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1723 </tr>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1724</table>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1725<p>Here are some examples of multidimensional arrays:</p>
1726<table class="layout">
1727 <tr class="layout">
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]1728 <td class="left"><tt>[3 x [4 x i32]]</tt></td>
1729 <td class="left">3x4 array of 32-bit integer values.</td>
1730 </tr>
1731 <tr class="layout">
1732 <td class="left"><tt>[12 x [10 x float]]</tt></td>
1733 <td class="left">12x10 array of single precision floating point values.</td>
1734 </tr>
1735 <tr class="layout">
1736 <td class="left"><tt>[2 x [3 x [4 x i16]]]</tt></td>
1737 <td class="left">2x3x4 array of 16-bit integer values.</td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1738 </tr>
1739</table>
Chris Lattnerc0ad71e2005-06-24 17:22:57 +0000[diff] [blame]1740
Dan Gohmanc74bc282009-11-09 19:01:53 +0000[diff] [blame]1741<p>There is no restriction on indexing beyond the end of the array implied by
1742 a static type (though there are restrictions on indexing beyond the bounds
1743 of an allocated object in some cases). This means that single-dimension
1744 'variable sized array' addressing can be implemented in LLVM with a zero
1745 length array type. An implementation of 'pascal style arrays' in LLVM could
1746 use the type "<tt>{ i32, [0 x float]}</tt>", for example.</p>
Chris Lattnerc0ad71e2005-06-24 17:22:57 +0000[diff] [blame]1747
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1748</div>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1749
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1750<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1751<div class="doc_subsubsection"> <a name="t_function">Function Type</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1752
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1753<div class="doc_text">
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]1754
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1755<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1756<p>The function type can be thought of as a function signature. It consists of
1757 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]1758 function type is a first class type or a void type.</p>
Devang Pateld6cff512008-03-10 20:49:15 +0000[diff] [blame]1759
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1760<h5>Syntax:</h5>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]1761<pre>
Nick Lewycky14d1ccc2009-09-27 07:55:32 +0000[diff] [blame]1762 &lt;returntype&gt; (&lt;parameter list&gt;)
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]1763</pre>
1764
John Criswell4c0cf7f2005-10-24 16:17:18 +0000[diff] [blame]1765<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]1766 specifiers. Optionally, the parameter list may include a type <tt>...</tt>,
1767 which indicates that the function takes a variable number of arguments.
1768 Variable argument functions can access their arguments with
1769 the <a href="#int_varargs">variable argument handling intrinsic</a>
Chris Lattner47f2a832010-03-02 06:36:51 +0000[diff] [blame]1770 functions. '<tt>&lt;returntype&gt;</tt>' is any type except
Nick Lewycky93e06a52009-09-27 23:27:42 +0000[diff] [blame]1771 <a href="#t_label">label</a>.</p>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]1772
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1773<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1774<table class="layout">
1775 <tr class="layout">
Reid Spencer58c08712006-12-31 07:18:34 +0000[diff] [blame]1776 <td class="left"><tt>i32 (i32)</tt></td>
1777 <td class="left">function taking an <tt>i32</tt>, returning an <tt>i32</tt>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1778 </td>
Reid Spencer58c08712006-12-31 07:18:34 +0000[diff] [blame]1779 </tr><tr class="layout">
Chris Lattner47f2a832010-03-02 06:36:51 +0000[diff] [blame]1780 <td class="left"><tt>float&nbsp;(i16,&nbsp;i32&nbsp;*)&nbsp;*
Reid Spencer655dcc62006-12-31 07:20:23 +0000[diff] [blame]1781 </tt></td>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]1782 <td class="left"><a href="#t_pointer">Pointer</a> to a function that takes
Chris Lattner47f2a832010-03-02 06:36:51 +0000[diff] [blame]1783 an <tt>i16</tt> and a <a href="#t_pointer">pointer</a> to <tt>i32</tt>,
1784 returning <tt>float</tt>.
Reid Spencer58c08712006-12-31 07:18:34 +0000[diff] [blame]1785 </td>
1786 </tr><tr class="layout">
1787 <td class="left"><tt>i32 (i8*, ...)</tt></td>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]1788 <td class="left">A vararg function that takes at least one
1789 <a href="#t_pointer">pointer</a> to <tt>i8 </tt> (char in C),
1790 which returns an integer. This is the signature for <tt>printf</tt> in
Reid Spencer58c08712006-12-31 07:18:34 +0000[diff] [blame]1791 LLVM.
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1792 </td>
Devang Patele3dfc1c2008-03-24 05:35:41 +0000[diff] [blame]1793 </tr><tr class="layout">
1794 <td class="left"><tt>{i32, i32} (i32)</tt></td>
Nick Lewycky14d1ccc2009-09-27 07:55:32 +0000[diff] [blame]1795 <td class="left">A function taking an <tt>i32</tt>, returning a
1796 <a href="#t_struct">structure</a> containing two <tt>i32</tt> values
Devang Patele3dfc1c2008-03-24 05:35:41 +0000[diff] [blame]1797 </td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1798 </tr>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1799</table>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]1800
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1801</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1802
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1803<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1804<div class="doc_subsubsection"> <a name="t_struct">Structure Type</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1805
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1806<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1807
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1808<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1809<p>The structure type is used to represent a collection of data members together
1810 in memory. The packing of the field types is defined to match the ABI of the
1811 underlying processor. The elements of a structure may be any type that has a
1812 size.</p>
1813
Jeffrey Yasskinf991bbb2010-01-11 19:19:26 +0000[diff] [blame]1814<p>Structures in memory are accessed using '<tt><a href="#i_load">load</a></tt>'
1815 and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a field
1816 with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.
1817 Structures in registers are accessed using the
1818 '<tt><a href="#i_extractvalue">extractvalue</a></tt>' and
1819 '<tt><a href="#i_insertvalue">insertvalue</a></tt>' instructions.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1820<h5>Syntax:</h5>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1821<pre>
1822 { &lt;type list&gt; }
1823</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1824
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1825<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1826<table class="layout">
1827 <tr class="layout">
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]1828 <td class="left"><tt>{ i32, i32, i32 }</tt></td>
1829 <td class="left">A triple of three <tt>i32</tt> values</td>
1830 </tr><tr class="layout">
1831 <td class="left"><tt>{&nbsp;float,&nbsp;i32&nbsp;(i32)&nbsp;*&nbsp;}</tt></td>
1832 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1833 second element is a <a href="#t_pointer">pointer</a> to a
1834 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1835 an <tt>i32</tt>.</td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1836 </tr>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1837</table>
Dan Gohman142ccc02009-01-24 15:58:40 +0000[diff] [blame]1838
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1839</div>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1840
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1841<!-- _______________________________________________________________________ -->
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]1842<div class="doc_subsubsection"> <a name="t_pstruct">Packed Structure Type</a>
1843</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1844
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]1845<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1846
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]1847<h5>Overview:</h5>
1848<p>The packed structure type is used to represent a collection of data members
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1849 together in memory. There is no padding between fields. Further, the
1850 alignment of a packed structure is 1 byte. The elements of a packed
1851 structure may be any type that has a size.</p>
1852
1853<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt> and
1854 '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a field with
1855 the '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
1856
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]1857<h5>Syntax:</h5>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1858<pre>
1859 &lt; { &lt;type list&gt; } &gt;
1860</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1861
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]1862<h5>Examples:</h5>
1863<table class="layout">
1864 <tr class="layout">
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]1865 <td class="left"><tt>&lt; { i32, i32, i32 } &gt;</tt></td>
1866 <td class="left">A triple of three <tt>i32</tt> values</td>
1867 </tr><tr class="layout">
Bill Wendlingb175fa42008-09-07 10:26:33 +0000[diff] [blame]1868 <td class="left">
1869<tt>&lt;&nbsp;{&nbsp;float,&nbsp;i32&nbsp;(i32)*&nbsp;}&nbsp;&gt;</tt></td>
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]1870 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1871 second element is a <a href="#t_pointer">pointer</a> to a
1872 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1873 an <tt>i32</tt>.</td>
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]1874 </tr>
1875</table>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1876
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]1877</div>
1878
1879<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1880<div class="doc_subsubsection"> <a name="t_pointer">Pointer Type</a> </div>
Chris Lattner4a67c912009-02-08 19:53:29 +0000[diff] [blame]1881
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1882<div class="doc_text">
1883
1884<h5>Overview:</h5>
Dan Gohman88481112010-02-25 16:50:07 +0000[diff] [blame]1885<p>The pointer type is used to specify memory locations.
1886 Pointers are commonly used to reference objects in memory.</p>
1887
1888<p>Pointer types may have an optional address space attribute defining the
1889 numbered address space where the pointed-to object resides. The default
1890 address space is number zero. The semantics of non-zero address
1891 spaces are target-specific.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1892
1893<p>Note that LLVM does not permit pointers to void (<tt>void*</tt>) nor does it
1894 permit pointers to labels (<tt>label*</tt>). Use <tt>i8*</tt> instead.</p>
Chris Lattner4a67c912009-02-08 19:53:29 +0000[diff] [blame]1895
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]1896<h5>Syntax:</h5>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1897<pre>
1898 &lt;type&gt; *
1899</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1900
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]1901<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1902<table class="layout">
1903 <tr class="layout">
Dan Gohman623806e2009-01-04 23:44:43 +0000[diff] [blame]1904 <td class="left"><tt>[4 x i32]*</tt></td>
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]1905 <td class="left">A <a href="#t_pointer">pointer</a> to <a
1906 href="#t_array">array</a> of four <tt>i32</tt> values.</td>
1907 </tr>
1908 <tr class="layout">
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]1909 <td class="left"><tt>i32 (i32*) *</tt></td>
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]1910 <td class="left"> A <a href="#t_pointer">pointer</a> to a <a
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1911 href="#t_function">function</a> that takes an <tt>i32*</tt>, returning an
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]1912 <tt>i32</tt>.</td>
1913 </tr>
1914 <tr class="layout">
1915 <td class="left"><tt>i32 addrspace(5)*</tt></td>
1916 <td class="left">A <a href="#t_pointer">pointer</a> to an <tt>i32</tt> value
1917 that resides in address space #5.</td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1918 </tr>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1919</table>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1920
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1921</div>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1922
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1923<!-- _______________________________________________________________________ -->
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]1924<div class="doc_subsubsection"> <a name="t_vector">Vector Type</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1925
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1926<div class="doc_text">
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1927
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1928<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1929<p>A vector type is a simple derived type that represents a vector of elements.
1930 Vector types are used when multiple primitive data are operated in parallel
1931 using a single instruction (SIMD). A vector type requires a size (number of
Duncan Sands31c0e0e2009-11-27 13:38:03 +0000[diff] [blame]1932 elements) and an underlying primitive data type. Vector types are considered
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1933 <a href="#t_firstclass">first class</a>.</p>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1934
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1935<h5>Syntax:</h5>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1936<pre>
1937 &lt; &lt;# elements&gt; x &lt;elementtype&gt; &gt;
1938</pre>
1939
Chris Lattnerf11031a2010-10-10 18:20:35 +0000[diff] [blame]1940<p>The number of elements is a constant integer value larger than 0; elementtype
1941 may be any integer or floating point type. Vectors of size zero are not
1942 allowed, and pointers are not allowed as the element type.</p>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1943
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1944<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1945<table class="layout">
1946 <tr class="layout">
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]1947 <td class="left"><tt>&lt;4 x i32&gt;</tt></td>
1948 <td class="left">Vector of 4 32-bit integer values.</td>
1949 </tr>
1950 <tr class="layout">
1951 <td class="left"><tt>&lt;8 x float&gt;</tt></td>
1952 <td class="left">Vector of 8 32-bit floating-point values.</td>
1953 </tr>
1954 <tr class="layout">
1955 <td class="left"><tt>&lt;2 x i64&gt;</tt></td>
1956 <td class="left">Vector of 2 64-bit integer values.</td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1957 </tr>
1958</table>
Dan Gohman142ccc02009-01-24 15:58:40 +0000[diff] [blame]1959
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1960</div>
1961
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1962<!-- _______________________________________________________________________ -->
1963<div class="doc_subsubsection"> <a name="t_opaque">Opaque Type</a> </div>
1964<div class="doc_text">
1965
1966<h5>Overview:</h5>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1967<p>Opaque types are used to represent unknown types in the system. This
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1968 corresponds (for example) to the C notion of a forward declared structure
1969 type. In LLVM, opaque types can eventually be resolved to any type (not just
1970 a structure type).</p>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1971
1972<h5>Syntax:</h5>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1973<pre>
1974 opaque
1975</pre>
1976
1977<h5>Examples:</h5>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1978<table class="layout">
1979 <tr class="layout">
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]1980 <td class="left"><tt>opaque</tt></td>
1981 <td class="left">An opaque type.</td>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1982 </tr>
1983</table>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1984
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1985</div>
1986
Chris Lattnercf7a5842009-02-02 07:32:36 +0000[diff] [blame]1987<!-- ======================================================================= -->
1988<div class="doc_subsection">
1989 <a name="t_uprefs">Type Up-references</a>
1990</div>
1991
1992<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1993
Chris Lattnercf7a5842009-02-02 07:32:36 +0000[diff] [blame]1994<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1995<p>An "up reference" allows you to refer to a lexically enclosing type without
1996 requiring it to have a name. For instance, a structure declaration may
1997 contain a pointer to any of the types it is lexically a member of. Example
1998 of up references (with their equivalent as named type declarations)
1999 include:</p>
Chris Lattnercf7a5842009-02-02 07:32:36 +0000[diff] [blame]2000
2001<pre>
Chris Lattnerbf1d5452009-02-09 10:00:56 +0000[diff] [blame]2002 { \2 * } %x = type { %x* }
Chris Lattnercf7a5842009-02-02 07:32:36 +0000[diff] [blame]2003 { \2 }* %y = type { %y }*
2004 \1* %z = type %z*
2005</pre>
2006
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2007<p>An up reference is needed by the asmprinter for printing out cyclic types
2008 when there is no declared name for a type in the cycle. Because the
2009 asmprinter does not want to print out an infinite type string, it needs a
2010 syntax to handle recursive types that have no names (all names are optional
2011 in llvm IR).</p>
Chris Lattnercf7a5842009-02-02 07:32:36 +0000[diff] [blame]2012
2013<h5>Syntax:</h5>
2014<pre>
2015 \&lt;level&gt;
2016</pre>
2017
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2018<p>The level is the count of the lexical type that is being referred to.</p>
Chris Lattnercf7a5842009-02-02 07:32:36 +0000[diff] [blame]2019
2020<h5>Examples:</h5>
Chris Lattnercf7a5842009-02-02 07:32:36 +0000[diff] [blame]2021<table class="layout">
2022 <tr class="layout">
2023 <td class="left"><tt>\1*</tt></td>
2024 <td class="left">Self-referential pointer.</td>
2025 </tr>
2026 <tr class="layout">
2027 <td class="left"><tt>{ { \3*, i8 }, i32 }</tt></td>
2028 <td class="left">Recursive structure where the upref refers to the out-most
2029 structure.</td>
2030 </tr>
2031</table>
Chris Lattnercf7a5842009-02-02 07:32:36 +0000[diff] [blame]2032
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2033</div>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]2034
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2035<!-- *********************************************************************** -->
2036<div class="doc_section"> <a name="constants">Constants</a> </div>
2037<!-- *********************************************************************** -->
2038
2039<div class="doc_text">
2040
2041<p>LLVM has several different basic types of constants. This section describes
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2042 them all and their syntax.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2043
2044</div>
2045
2046<!-- ======================================================================= -->
Reid Spencer8f08d802004-12-09 18:02:53 +0000[diff] [blame]2047<div class="doc_subsection"><a name="simpleconstants">Simple Constants</a></div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2048
2049<div class="doc_text">
2050
2051<dl>
2052 <dt><b>Boolean constants</b></dt>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2053 <dd>The two strings '<tt>true</tt>' and '<tt>false</tt>' are both valid
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]2054 constants of the <tt><a href="#t_integer">i1</a></tt> type.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2055
2056 <dt><b>Integer constants</b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2057 <dd>Standard integers (such as '4') are constants of
2058 the <a href="#t_integer">integer</a> type. Negative numbers may be used
2059 with integer types.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2060
2061 <dt><b>Floating point constants</b></dt>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2062 <dd>Floating point constants use standard decimal notation (e.g. 123.421),
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2063 exponential notation (e.g. 1.23421e+2), or a more precise hexadecimal
2064 notation (see below). The assembler requires the exact decimal value of a
2065 floating-point constant. For example, the assembler accepts 1.25 but
2066 rejects 1.3 because 1.3 is a repeating decimal in binary. Floating point
2067 constants must have a <a href="#t_floating">floating point</a> type. </dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2068
2069 <dt><b>Null pointer constants</b></dt>
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]2070 <dd>The identifier '<tt>null</tt>' is recognized as a null pointer constant
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2071 and must be of <a href="#t_pointer">pointer type</a>.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2072</dl>
2073
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2074<p>The one non-intuitive notation for constants is the hexadecimal form of
2075 floating point constants. For example, the form '<tt>double
2076 0x432ff973cafa8000</tt>' is equivalent to (but harder to read than)
2077 '<tt>double 4.5e+15</tt>'. The only time hexadecimal floating point
2078 constants are required (and the only time that they are generated by the
2079 disassembler) is when a floating point constant must be emitted but it cannot
2080 be represented as a decimal floating point number in a reasonable number of
2081 digits. For example, NaN's, infinities, and other special values are
2082 represented in their IEEE hexadecimal format so that assembly and disassembly
2083 do not cause any bits to change in the constants.</p>
2084
Dale Johannesencd4a3012009-02-11 22:14:51 +0000[diff] [blame]2085<p>When using the hexadecimal form, constants of types float and double are
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2086 represented using the 16-digit form shown above (which matches the IEEE754
2087 representation for double); float values must, however, be exactly
2088 representable as IEE754 single precision. Hexadecimal format is always used
2089 for long double, and there are three forms of long double. The 80-bit format
2090 used by x86 is represented as <tt>0xK</tt> followed by 20 hexadecimal digits.
2091 The 128-bit format used by PowerPC (two adjacent doubles) is represented
2092 by <tt>0xM</tt> followed by 32 hexadecimal digits. The IEEE 128-bit format
2093 is represented by <tt>0xL</tt> followed by 32 hexadecimal digits; no
2094 currently supported target uses this format. Long doubles will only work if
2095 they match the long double format on your target. All hexadecimal formats
2096 are big-endian (sign bit at the left).</p>
2097
Dale Johannesen33e5c352010-10-01 00:48:59 +0000[diff] [blame]2098<p>There are no constants of type x86mmx.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2099</div>
2100
2101<!-- ======================================================================= -->
Chris Lattner361bfcd2009-02-28 18:32:25 +0000[diff] [blame]2102<div class="doc_subsection">
Bill Wendling972b7202009-07-20 02:32:41 +0000[diff] [blame]2103<a name="aggregateconstants"></a> <!-- old anchor -->
2104<a name="complexconstants">Complex Constants</a>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2105</div>
2106
2107<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2108
Chris Lattner361bfcd2009-02-28 18:32:25 +0000[diff] [blame]2109<p>Complex constants are a (potentially recursive) combination of simple
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2110 constants and smaller complex constants.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2111
2112<dl>
2113 <dt><b>Structure constants</b></dt>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2114 <dd>Structure constants are represented with notation similar to structure
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2115 type definitions (a comma separated list of elements, surrounded by braces
2116 (<tt>{}</tt>)). For example: "<tt>{ i32 4, float 17.0, i32* @G }</tt>",
2117 where "<tt>@G</tt>" is declared as "<tt>@G = external global i32</tt>".
2118 Structure constants must have <a href="#t_struct">structure type</a>, and
2119 the number and types of elements must match those specified by the
2120 type.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2121
2122 <dt><b>Array constants</b></dt>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2123 <dd>Array constants are represented with notation similar to array type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2124 definitions (a comma separated list of elements, surrounded by square
2125 brackets (<tt>[]</tt>)). For example: "<tt>[ i32 42, i32 11, i32 74
2126 ]</tt>". Array constants must have <a href="#t_array">array type</a>, and
2127 the number and types of elements must match those specified by the
2128 type.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2129
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]2130 <dt><b>Vector constants</b></dt>
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]2131 <dd>Vector constants are represented with notation similar to vector type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2132 definitions (a comma separated list of elements, surrounded by
2133 less-than/greater-than's (<tt>&lt;&gt;</tt>)). For example: "<tt>&lt; i32
2134 42, i32 11, i32 74, i32 100 &gt;</tt>". Vector constants must
2135 have <a href="#t_vector">vector type</a>, and the number and types of
2136 elements must match those specified by the type.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2137
2138 <dt><b>Zero initialization</b></dt>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2139 <dd>The string '<tt>zeroinitializer</tt>' can be used to zero initialize a
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]2140 value to zero of <em>any</em> type, including scalar and
2141 <a href="#t_aggregate">aggregate</a> types.
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2142 This is often used to avoid having to print large zero initializers
2143 (e.g. for large arrays) and is always exactly equivalent to using explicit
2144 zero initializers.</dd>
Nick Lewycky49f89192009-04-04 07:22:01 +0000[diff] [blame]2145
2146 <dt><b>Metadata node</b></dt>
Nick Lewycky8e2c4f42009-05-30 16:08:30 +0000[diff] [blame]2147 <dd>A metadata node is a structure-like constant with
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2148 <a href="#t_metadata">metadata type</a>. For example: "<tt>metadata !{
2149 i32 0, metadata !"test" }</tt>". Unlike other constants that are meant to
2150 be interpreted as part of the instruction stream, metadata is a place to
2151 attach additional information such as debug info.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2152</dl>
2153
2154</div>
2155
2156<!-- ======================================================================= -->
2157<div class="doc_subsection">
2158 <a name="globalconstants">Global Variable and Function Addresses</a>
2159</div>
2160
2161<div class="doc_text">
2162
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2163<p>The addresses of <a href="#globalvars">global variables</a>
2164 and <a href="#functionstructure">functions</a> are always implicitly valid
2165 (link-time) constants. These constants are explicitly referenced when
2166 the <a href="#identifiers">identifier for the global</a> is used and always
2167 have <a href="#t_pointer">pointer</a> type. For example, the following is a
2168 legal LLVM file:</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2169
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2170<pre class="doc_code">
Chris Lattner00538a12007-06-06 18:28:13 +0000[diff] [blame]2171@X = global i32 17
2172@Y = global i32 42
2173@Z = global [2 x i32*] [ i32* @X, i32* @Y ]
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2174</pre>
2175
2176</div>
2177
2178<!-- ======================================================================= -->
Reid Spencer641f5c92004-12-09 18:13:12 +0000[diff] [blame]2179<div class="doc_subsection"><a name="undefvalues">Undefined Values</a></div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2180<div class="doc_text">
2181
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2182<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]2183 indicates that the user of the value may receive an unspecified bit-pattern.
Bill Wendling6bbe0912010-10-27 01:07:41 +0000[diff] [blame]2184 Undefined values may be of any type (other than '<tt>label</tt>'
2185 or '<tt>void</tt>') and be used anywhere a constant is permitted.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2186
Chris Lattner92ada5d2009-09-11 01:49:31 +0000[diff] [blame]2187<p>Undefined values are useful because they indicate to the compiler that the
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2188 program is well defined no matter what value is used. This gives the
2189 compiler more freedom to optimize. Here are some examples of (potentially
2190 surprising) transformations that are valid (in pseudo IR):</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2191
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2192
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2193<pre class="doc_code">
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2194 %A = add %X, undef
2195 %B = sub %X, undef
2196 %C = xor %X, undef
2197Safe:
2198 %A = undef
2199 %B = undef
2200 %C = undef
2201</pre>
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2202
2203<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]2204 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]2205
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2206<pre class="doc_code">
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2207 %A = or %X, undef
2208 %B = and %X, undef
2209Safe:
2210 %A = -1
2211 %B = 0
2212Unsafe:
2213 %A = undef
2214 %B = undef
2215</pre>
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2216
2217<p>These logical operations have bits that are not always affected by the input.
Bill Wendling6bbe0912010-10-27 01:07:41 +0000[diff] [blame]2218 For example, if <tt>%X</tt> has a zero bit, then the output of the
2219 '<tt>and</tt>' operation will always be a zero for that bit, no matter what
2220 the corresponding bit from the '<tt>undef</tt>' is. As such, it is unsafe to
2221 optimize or assume that the result of the '<tt>and</tt>' is '<tt>undef</tt>'.
2222 However, it is safe to assume that all bits of the '<tt>undef</tt>' could be
2223 0, and optimize the '<tt>and</tt>' to 0. Likewise, it is safe to assume that
2224 all the bits of the '<tt>undef</tt>' operand to the '<tt>or</tt>' could be
2225 set, allowing the '<tt>or</tt>' to be folded to -1.</p>
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2226
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2227<pre class="doc_code">
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2228 %A = select undef, %X, %Y
2229 %B = select undef, 42, %Y
2230 %C = select %X, %Y, undef
2231Safe:
2232 %A = %X (or %Y)
2233 %B = 42 (or %Y)
2234 %C = %Y
2235Unsafe:
2236 %A = undef
2237 %B = undef
2238 %C = undef
2239</pre>
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2240
Bill Wendling6bbe0912010-10-27 01:07:41 +0000[diff] [blame]2241<p>This set of examples shows that undefined '<tt>select</tt>' (and conditional
2242 branch) conditions can go <em>either way</em>, but they have to come from one
2243 of the two operands. In the <tt>%A</tt> example, if <tt>%X</tt> and
2244 <tt>%Y</tt> were both known to have a clear low bit, then <tt>%A</tt> would
2245 have to have a cleared low bit. However, in the <tt>%C</tt> example, the
2246 optimizer is allowed to assume that the '<tt>undef</tt>' operand could be the
2247 same as <tt>%Y</tt>, allowing the whole '<tt>select</tt>' to be
2248 eliminated.</p>
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2249
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2250<pre class="doc_code">
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2251 %A = xor undef, undef
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]2252
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2253 %B = undef
2254 %C = xor %B, %B
2255
2256 %D = undef
2257 %E = icmp lt %D, 4
2258 %F = icmp gte %D, 4
2259
2260Safe:
2261 %A = undef
2262 %B = undef
2263 %C = undef
2264 %D = undef
2265 %E = undef
2266 %F = undef
2267</pre>
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2268
Bill Wendling6bbe0912010-10-27 01:07:41 +0000[diff] [blame]2269<p>This example points out that two '<tt>undef</tt>' operands are not
2270 necessarily the same. This can be surprising to people (and also matches C
2271 semantics) where they assume that "<tt>X^X</tt>" is always zero, even
2272 if <tt>X</tt> is undefined. This isn't true for a number of reasons, but the
2273 short answer is that an '<tt>undef</tt>' "variable" can arbitrarily change
2274 its value over its "live range". This is true because the variable doesn't
2275 actually <em>have a live range</em>. Instead, the value is logically read
2276 from arbitrary registers that happen to be around when needed, so the value
2277 is not necessarily consistent over time. In fact, <tt>%A</tt> and <tt>%C</tt>
2278 need to have the same semantics or the core LLVM "replace all uses with"
2279 concept would not hold.</p>
Chris Lattnera34a7182009-09-07 23:33:52 +0000[diff] [blame]2280
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2281<pre class="doc_code">
Chris Lattnera34a7182009-09-07 23:33:52 +0000[diff] [blame]2282 %A = fdiv undef, %X
2283 %B = fdiv %X, undef
2284Safe:
2285 %A = undef
2286b: unreachable
2287</pre>
Chris Lattnera34a7182009-09-07 23:33:52 +0000[diff] [blame]2288
2289<p>These examples show the crucial difference between an <em>undefined
Bill Wendling6bbe0912010-10-27 01:07:41 +0000[diff] [blame]2290 value</em> and <em>undefined behavior</em>. An undefined value (like
2291 '<tt>undef</tt>') is allowed to have an arbitrary bit-pattern. This means that
2292 the <tt>%A</tt> operation can be constant folded to '<tt>undef</tt>', because
2293 the '<tt>undef</tt>' could be an SNaN, and <tt>fdiv</tt> is not (currently)
2294 defined on SNaN's. However, in the second example, we can make a more
2295 aggressive assumption: because the <tt>undef</tt> is allowed to be an
2296 arbitrary value, we are allowed to assume that it could be zero. Since a
2297 divide by zero has <em>undefined behavior</em>, we are allowed to assume that
2298 the operation does not execute at all. This allows us to delete the divide and
2299 all code after it. Because the undefined operation "can't happen", the
2300 optimizer can assume that it occurs in dead code.</p>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]2301
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2302<pre class="doc_code">
Chris Lattnera34a7182009-09-07 23:33:52 +0000[diff] [blame]2303a: store undef -> %X
2304b: store %X -> undef
2305Safe:
2306a: &lt;deleted&gt;
2307b: unreachable
2308</pre>
Chris Lattnera34a7182009-09-07 23:33:52 +0000[diff] [blame]2309
Bill Wendling6bbe0912010-10-27 01:07:41 +0000[diff] [blame]2310<p>These examples reiterate the <tt>fdiv</tt> example: a store <em>of</em> an
2311 undefined value can be assumed to not have any effect; we can assume that the
2312 value is overwritten with bits that happen to match what was already there.
2313 However, a store <em>to</em> an undefined location could clobber arbitrary
2314 memory, therefore, it has undefined behavior.</p>
Chris Lattnera34a7182009-09-07 23:33:52 +0000[diff] [blame]2315
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2316</div>
2317
2318<!-- ======================================================================= -->
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]2319<div class="doc_subsection"><a name="trapvalues">Trap Values</a></div>
2320<div class="doc_text">
2321
Dan Gohmanb2a709b2010-04-26 20:21:21 +0000[diff] [blame]2322<p>Trap values are similar to <a href="#undefvalues">undef values</a>, however
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]2323 instead of representing an unspecified bit pattern, they represent the
2324 fact that an instruction or constant expression which cannot evoke side
2325 effects has nevertheless detected a condition which results in undefined
Dan Gohmanb2a709b2010-04-26 20:21:21 +0000[diff] [blame]2326 behavior.</p>
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]2327
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2328<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]2329 only exist when produced by operations such as
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2330 <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]2331
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2332<p>Trap value behavior is defined in terms of value <i>dependence</i>:</p>
Dan Gohmanb8b85c12010-04-26 23:36:52 +0000[diff] [blame]2333
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2334<ul>
2335<li>Values other than <a href="#i_phi"><tt>phi</tt></a> nodes depend on
2336 their operands.</li>
2337
2338<li><a href="#i_phi"><tt>Phi</tt></a> nodes depend on the operand corresponding
2339 to their dynamic predecessor basic block.</li>
2340
2341<li>Function arguments depend on the corresponding actual argument values in
2342 the dynamic callers of their functions.</li>
2343
2344<li><a href="#i_call"><tt>Call</tt></a> instructions depend on the
2345 <a href="#i_ret"><tt>ret</tt></a> instructions that dynamically transfer
2346 control back to them.</li>
2347
Dan Gohman7292a752010-05-03 14:55:22 +0000[diff] [blame]2348<li><a href="#i_invoke"><tt>Invoke</tt></a> instructions depend on the
2349 <a href="#i_ret"><tt>ret</tt></a>, <a href="#i_unwind"><tt>unwind</tt></a>,
2350 or exception-throwing call instructions that dynamically transfer control
2351 back to them.</li>
2352
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2353<li>Non-volatile loads and stores depend on the most recent stores to all of the
2354 referenced memory addresses, following the order in the IR
2355 (including loads and stores implied by intrinsics such as
2356 <a href="#int_memcpy"><tt>@llvm.memcpy</tt></a>.)</li>
2357
Dan Gohman3513ea52010-05-03 14:59:34 +0000[diff] [blame]2358<!-- TODO: In the case of multiple threads, this only applies if the store
2359 "happens-before" the load or store. -->
Dan Gohmanb8b85c12010-04-26 23:36:52 +0000[diff] [blame]2360
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2361<!-- TODO: floating-point exception state -->
Dan Gohmanb8b85c12010-04-26 23:36:52 +0000[diff] [blame]2362
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2363<li>An instruction with externally visible side effects depends on the most
2364 recent preceding instruction with externally visible side effects, following
Dan Gohman6c858db2010-07-06 15:26:33 +0000[diff] [blame]2365 the order in the IR. (This includes
2366 <a href="#volatile">volatile operations</a>.)</li>
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]2367
Dan Gohman7292a752010-05-03 14:55:22 +0000[diff] [blame]2368<li>An instruction <i>control-depends</i> on a
2369 <a href="#terminators">terminator instruction</a>
2370 if the terminator instruction has multiple successors and the instruction
2371 is always executed when control transfers to one of the successors, and
2372 may not be executed when control is transfered to another.</li>
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2373
2374<li>Dependence is transitive.</li>
2375
2376</ul>
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2377
2378<p>Whenever a trap value is generated, all values which depend on it evaluate
2379 to trap. If they have side effects, the evoke their side effects as if each
2380 operand with a trap value were undef. If they have externally-visible side
2381 effects, the behavior is undefined.</p>
2382
2383<p>Here are some examples:</p>
Dan Gohman48a25882010-04-26 20:54:53 +0000[diff] [blame]2384
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2385<pre class="doc_code">
Dan Gohmanb8b85c12010-04-26 23:36:52 +0000[diff] [blame]2386entry:
2387 %trap = sub nuw i32 0, 1 ; Results in a trap value.
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2388 %still_trap = and i32 %trap, 0 ; Whereas (and i32 undef, 0) would return 0.
2389 %trap_yet_again = getelementptr i32* @h, i32 %still_trap
2390 store i32 0, i32* %trap_yet_again ; undefined behavior
2391
2392 store i32 %trap, i32* @g ; Trap value conceptually stored to memory.
2393 %trap2 = load i32* @g ; Returns a trap value, not just undef.
2394
2395 volatile store i32 %trap, i32* @g ; External observation; undefined behavior.
2396
2397 %narrowaddr = bitcast i32* @g to i16*
2398 %wideaddr = bitcast i32* @g to i64*
2399 %trap3 = load 16* %narrowaddr ; Returns a trap value.
2400 %trap4 = load i64* %widaddr ; Returns a trap value.
2401
2402 %cmp = icmp i32 slt %trap, 0 ; Returns a trap value.
Dan Gohmanb8b85c12010-04-26 23:36:52 +0000[diff] [blame]2403 %br i1 %cmp, %true, %end ; Branch to either destination.
2404
2405true:
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2406 volatile store i32 0, i32* @g ; This is control-dependent on %cmp, so
2407 ; it has undefined behavior.
Dan Gohmanb8b85c12010-04-26 23:36:52 +0000[diff] [blame]2408 br label %end
2409
2410end:
2411 %p = phi i32 [ 0, %entry ], [ 1, %true ]
2412 ; Both edges into this PHI are
2413 ; control-dependent on %cmp, so this
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2414 ; always results in a trap value.
Dan Gohmanb8b85c12010-04-26 23:36:52 +0000[diff] [blame]2415
2416 volatile store i32 0, i32* @g ; %end is control-equivalent to %entry
2417 ; so this is defined (ignoring earlier
2418 ; undefined behavior in this example).
Dan Gohmanb8b85c12010-04-26 23:36:52 +0000[diff] [blame]2419</pre>
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]2420
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]2421</div>
2422
2423<!-- ======================================================================= -->
Chris Lattner2bfd3202009-10-27 21:19:13 +0000[diff] [blame]2424<div class="doc_subsection"><a name="blockaddress">Addresses of Basic
2425 Blocks</a></div>
Chris Lattnere4801f72009-10-27 21:01:34 +0000[diff] [blame]2426<div class="doc_text">
2427
Chris Lattneraa99c942009-11-01 01:27:45 +0000[diff] [blame]2428<p><b><tt>blockaddress(@function, %block)</tt></b></p>
Chris Lattnere4801f72009-10-27 21:01:34 +0000[diff] [blame]2429
2430<p>The '<tt>blockaddress</tt>' constant computes the address of the specified
Chris Lattner5c5f0ac2009-10-27 21:49:40 +0000[diff] [blame]2431 basic block in the specified function, and always has an i8* type. Taking
Chris Lattneraa99c942009-11-01 01:27:45 +0000[diff] [blame]2432 the address of the entry block is illegal.</p>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]2433
Chris Lattnere4801f72009-10-27 21:01:34 +0000[diff] [blame]2434<p>This value only has defined behavior when used as an operand to the
Bill Wendling6bbe0912010-10-27 01:07:41 +0000[diff] [blame]2435 '<a href="#i_indirectbr"><tt>indirectbr</tt></a>' instruction, or for
2436 comparisons against null. Pointer equality tests between labels addresses
2437 results in undefined behavior &mdash; though, again, comparison against null
2438 is ok, and no label is equal to the null pointer. This may be passed around
2439 as an opaque pointer sized value as long as the bits are not inspected. This
2440 allows <tt>ptrtoint</tt> and arithmetic to be performed on these values so
2441 long as the original value is reconstituted before the <tt>indirectbr</tt>
2442 instruction.</p>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]2443
Bill Wendling6bbe0912010-10-27 01:07:41 +0000[diff] [blame]2444<p>Finally, some targets may provide defined semantics when using the value as
2445 the operand to an inline assembly, but that is target specific.</p>
Chris Lattnere4801f72009-10-27 21:01:34 +0000[diff] [blame]2446
2447</div>
2448
2449
2450<!-- ======================================================================= -->
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2451<div class="doc_subsection"><a name="constantexprs">Constant Expressions</a>
2452</div>
2453
2454<div class="doc_text">
2455
2456<p>Constant expressions are used to allow expressions involving other constants
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2457 to be used as constants. Constant expressions may be of
2458 any <a href="#t_firstclass">first class</a> type and may involve any LLVM
2459 operation that does not have side effects (e.g. load and call are not
Bill Wendling6bbe0912010-10-27 01:07:41 +0000[diff] [blame]2460 supported). The following is the syntax for constant expressions:</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2461
2462<dl>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2463 <dt><b><tt>trunc (CST to TYPE)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2464 <dd>Truncate a constant to another type. The bit size of CST must be larger
2465 than the bit size of TYPE. Both types must be integers.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2466
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2467 <dt><b><tt>zext (CST to TYPE)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2468 <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]2469 smaller than the bit size of TYPE. Both types must be integers.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2470
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2471 <dt><b><tt>sext (CST to TYPE)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2472 <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]2473 smaller than the bit size of TYPE. Both types must be integers.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2474
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2475 <dt><b><tt>fptrunc (CST to TYPE)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2476 <dd>Truncate a floating point constant to another floating point type. The
2477 size of CST must be larger than the size of TYPE. Both types must be
2478 floating point.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2479
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2480 <dt><b><tt>fpext (CST to TYPE)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2481 <dd>Floating point extend a constant to another type. The size of CST must be
2482 smaller or equal to the size of TYPE. Both types must be floating
2483 point.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2484
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2485 <dt><b><tt>fptoui (CST to TYPE)</tt></b></dt>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2486 <dd>Convert a floating point constant to the corresponding unsigned integer
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2487 constant. TYPE must be a scalar or vector integer type. CST must be of
2488 scalar or vector floating point type. Both CST and TYPE must be scalars,
2489 or vectors of the same number of elements. If the value won't fit in the
2490 integer type, the results are undefined.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2491
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2492 <dt><b><tt>fptosi (CST to TYPE)</tt></b></dt>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2493 <dd>Convert a floating point constant to the corresponding signed integer
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2494 constant. TYPE must be a scalar or vector integer type. CST must be of
2495 scalar or vector floating point type. Both CST and TYPE must be scalars,
2496 or vectors of the same number of elements. If the value won't fit in the
2497 integer type, the results are undefined.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2498
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2499 <dt><b><tt>uitofp (CST to TYPE)</tt></b></dt>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2500 <dd>Convert an unsigned integer constant to the corresponding floating point
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2501 constant. TYPE must be a scalar or vector floating point type. CST must be
2502 of scalar or vector integer type. Both CST and TYPE must be scalars, or
2503 vectors of the same number of elements. If the value won't fit in the
2504 floating point type, the results are undefined.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2505
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2506 <dt><b><tt>sitofp (CST to TYPE)</tt></b></dt>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2507 <dd>Convert a signed integer constant to the corresponding floating point
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2508 constant. TYPE must be a scalar or vector floating point type. CST must be
2509 of scalar or vector integer type. Both CST and TYPE must be scalars, or
2510 vectors of the same number of elements. If the value won't fit in the
2511 floating point type, the results are undefined.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2512
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2513 <dt><b><tt>ptrtoint (CST to TYPE)</tt></b></dt>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]2514 <dd>Convert a pointer typed constant to the corresponding integer constant
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2515 <tt>TYPE</tt> must be an integer type. <tt>CST</tt> must be of pointer
2516 type. The <tt>CST</tt> value is zero extended, truncated, or unchanged to
2517 make it fit in <tt>TYPE</tt>.</dd>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]2518
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2519 <dt><b><tt>inttoptr (CST to TYPE)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2520 <dd>Convert a integer constant to a pointer constant. TYPE must be a pointer
2521 type. CST must be of integer type. The CST value is zero extended,
2522 truncated, or unchanged to make it fit in a pointer size. This one is
2523 <i>really</i> dangerous!</dd>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]2524
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2525 <dt><b><tt>bitcast (CST to TYPE)</tt></b></dt>
Chris Lattner789dee32009-02-28 18:27:03 +0000[diff] [blame]2526 <dd>Convert a constant, CST, to another TYPE. The constraints of the operands
2527 are the same as those for the <a href="#i_bitcast">bitcast
2528 instruction</a>.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2529
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2530 <dt><b><tt>getelementptr (CSTPTR, IDX0, IDX1, ...)</tt></b></dt>
2531 <dt><b><tt>getelementptr inbounds (CSTPTR, IDX0, IDX1, ...)</tt></b></dt>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2532 <dd>Perform the <a href="#i_getelementptr">getelementptr operation</a> on
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2533 constants. As with the <a href="#i_getelementptr">getelementptr</a>
2534 instruction, the index list may have zero or more indexes, which are
2535 required to make sense for the type of "CSTPTR".</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2536
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2537 <dt><b><tt>select (COND, VAL1, VAL2)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2538 <dd>Perform the <a href="#i_select">select operation</a> on constants.</dd>
Reid Spencer9965ee72006-12-04 19:23:19 +0000[diff] [blame]2539
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2540 <dt><b><tt>icmp COND (VAL1, VAL2)</tt></b></dt>
Reid Spencer9965ee72006-12-04 19:23:19 +0000[diff] [blame]2541 <dd>Performs the <a href="#i_icmp">icmp operation</a> on constants.</dd>
2542
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2543 <dt><b><tt>fcmp COND (VAL1, VAL2)</tt></b></dt>
Reid Spencer9965ee72006-12-04 19:23:19 +0000[diff] [blame]2544 <dd>Performs the <a href="#i_fcmp">fcmp operation</a> on constants.</dd>
Robert Bocchino7e97a6d2006-01-10 19:31:34 +0000[diff] [blame]2545
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2546 <dt><b><tt>extractelement (VAL, IDX)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2547 <dd>Perform the <a href="#i_extractelement">extractelement operation</a> on
2548 constants.</dd>
Robert Bocchino7e97a6d2006-01-10 19:31:34 +0000[diff] [blame]2549
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2550 <dt><b><tt>insertelement (VAL, ELT, IDX)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2551 <dd>Perform the <a href="#i_insertelement">insertelement operation</a> on
2552 constants.</dd>
Chris Lattner016a0e52006-04-08 00:13:41 +0000[diff] [blame]2553
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2554 <dt><b><tt>shufflevector (VEC1, VEC2, IDXMASK)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2555 <dd>Perform the <a href="#i_shufflevector">shufflevector operation</a> on
2556 constants.</dd>
Chris Lattner016a0e52006-04-08 00:13:41 +0000[diff] [blame]2557
Nick Lewycky9ab9a7f2010-05-29 06:44:15 +0000[diff] [blame]2558 <dt><b><tt>extractvalue (VAL, IDX0, IDX1, ...)</tt></b></dt>
2559 <dd>Perform the <a href="#i_extractvalue">extractvalue operation</a> on
2560 constants. The index list is interpreted in a similar manner as indices in
2561 a '<a href="#i_getelementptr">getelementptr</a>' operation. At least one
2562 index value must be specified.</dd>
2563
2564 <dt><b><tt>insertvalue (VAL, ELT, IDX0, IDX1, ...)</tt></b></dt>
2565 <dd>Perform the <a href="#i_insertvalue">insertvalue operation</a> on
2566 constants. The index list is interpreted in a similar manner as indices in
2567 a '<a href="#i_getelementptr">getelementptr</a>' operation. At least one
2568 index value must be specified.</dd>
2569
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2570 <dt><b><tt>OPCODE (LHS, RHS)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2571 <dd>Perform the specified operation of the LHS and RHS constants. OPCODE may
2572 be any of the <a href="#binaryops">binary</a>
2573 or <a href="#bitwiseops">bitwise binary</a> operations. The constraints
2574 on operands are the same as those for the corresponding instruction
2575 (e.g. no bitwise operations on floating point values are allowed).</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2576</dl>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2577
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2578</div>
Chris Lattnerb1652612004-03-08 16:49:10 +0000[diff] [blame]2579
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2580<!-- *********************************************************************** -->
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2581<div class="doc_section"> <a name="othervalues">Other Values</a> </div>
2582<!-- *********************************************************************** -->
2583
2584<!-- ======================================================================= -->
2585<div class="doc_subsection">
2586<a name="inlineasm">Inline Assembler Expressions</a>
2587</div>
2588
2589<div class="doc_text">
2590
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2591<p>LLVM supports inline assembler expressions (as opposed
2592 to <a href="#moduleasm"> Module-Level Inline Assembly</a>) through the use of
2593 a special value. This value represents the inline assembler as a string
2594 (containing the instructions to emit), a list of operand constraints (stored
Dale Johannesen63c94fe2009-10-13 21:56:55 +0000[diff] [blame]2595 as a string), a flag that indicates whether or not the inline asm
Dale Johannesen1cfb9582009-10-21 23:28:00 +0000[diff] [blame]2596 expression has side effects, and a flag indicating whether the function
2597 containing the asm needs to align its stack conservatively. An example
2598 inline assembler expression is:</p>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2599
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2600<pre class="doc_code">
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2601i32 (i32) asm "bswap $0", "=r,r"
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2602</pre>
2603
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2604<p>Inline assembler expressions may <b>only</b> be used as the callee operand of
2605 a <a href="#i_call"><tt>call</tt> instruction</a>. Thus, typically we
2606 have:</p>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2607
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2608<pre class="doc_code">
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2609%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]2610</pre>
2611
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2612<p>Inline asms with side effects not visible in the constraint list must be
2613 marked as having side effects. This is done through the use of the
2614 '<tt>sideeffect</tt>' keyword, like so:</p>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2615
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2616<pre class="doc_code">
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2617call void asm sideeffect "eieio", ""()
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2618</pre>
2619
Dale Johannesen1cfb9582009-10-21 23:28:00 +0000[diff] [blame]2620<p>In some cases inline asms will contain code that will not work unless the
2621 stack is aligned in some way, such as calls or SSE instructions on x86,
2622 yet will not contain code that does that alignment within the asm.
2623 The compiler should make conservative assumptions about what the asm might
2624 contain and should generate its usual stack alignment code in the prologue
2625 if the '<tt>alignstack</tt>' keyword is present:</p>
Dale Johannesen63c94fe2009-10-13 21:56:55 +0000[diff] [blame]2626
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2627<pre class="doc_code">
Dale Johannesen1cfb9582009-10-21 23:28:00 +0000[diff] [blame]2628call void asm alignstack "eieio", ""()
Dale Johannesen63c94fe2009-10-13 21:56:55 +0000[diff] [blame]2629</pre>
Dale Johannesen63c94fe2009-10-13 21:56:55 +0000[diff] [blame]2630
2631<p>If both keywords appear the '<tt>sideeffect</tt>' keyword must come
2632 first.</p>
2633
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2634<p>TODO: The format of the asm and constraints string still need to be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2635 documented here. Constraints on what can be done (e.g. duplication, moving,
2636 etc need to be documented). This is probably best done by reference to
2637 another document that covers inline asm from a holistic perspective.</p>
Chris Lattner51065562010-04-07 05:38:05 +0000[diff] [blame]2638</div>
2639
2640<div class="doc_subsubsection">
2641<a name="inlineasm_md">Inline Asm Metadata</a>
2642</div>
2643
2644<div class="doc_text">
2645
2646<p>The call instructions that wrap inline asm nodes may have a "!srcloc" MDNode
Chris Lattner79ffdc72010-11-17 08:20:42 +0000[diff] [blame]2647 attached to it that contains a list of constant integers. If present, the
2648 code generator will use the integer as the location cookie value when report
Chris Lattner51065562010-04-07 05:38:05 +0000[diff] [blame]2649 errors through the LLVMContext error reporting mechanisms. This allows a
Dan Gohman61110ae2010-04-28 00:36:01 +0000[diff] [blame]2650 front-end to correlate backend errors that occur with inline asm back to the
Chris Lattner51065562010-04-07 05:38:05 +0000[diff] [blame]2651 source code that produced it. For example:</p>
2652
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2653<pre class="doc_code">
Chris Lattner51065562010-04-07 05:38:05 +0000[diff] [blame]2654call void asm sideeffect "something bad", ""()<b>, !srcloc !42</b>
2655...
2656!42 = !{ i32 1234567 }
2657</pre>
Chris Lattner51065562010-04-07 05:38:05 +0000[diff] [blame]2658
2659<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]2660 IR. If the MDNode contains multiple constants, the code generator will use
2661 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]2662
2663</div>
2664
Chris Lattnerc2f8f162010-01-15 21:50:19 +0000[diff] [blame]2665<!-- ======================================================================= -->
2666<div class="doc_subsection"><a name="metadata">Metadata Nodes and Metadata
2667 Strings</a>
2668</div>
2669
2670<div class="doc_text">
2671
2672<p>LLVM IR allows metadata to be attached to instructions in the program that
2673 can convey extra information about the code to the optimizers and code
2674 generator. One example application of metadata is source-level debug
2675 information. There are two metadata primitives: strings and nodes. All
2676 metadata has the <tt>metadata</tt> type and is identified in syntax by a
2677 preceding exclamation point ('<tt>!</tt>').</p>
2678
2679<p>A metadata string is a string surrounded by double quotes. It can contain
2680 any character by escaping non-printable characters with "\xx" where "xx" is
2681 the two digit hex code. For example: "<tt>!"test\00"</tt>".</p>
2682
2683<p>Metadata nodes are represented with notation similar to structure constants
2684 (a comma separated list of elements, surrounded by braces and preceded by an
2685 exclamation point). For example: "<tt>!{ metadata !"test\00", i32
2686 10}</tt>". Metadata nodes can have any values as their operand.</p>
2687
2688<p>A <a href="#namedmetadatastructure">named metadata</a> is a collection of
2689 metadata nodes, which can be looked up in the module symbol table. For
2690 example: "<tt>!foo = metadata !{!4, !3}</tt>".
2691
Devang Patel9984bd62010-03-04 23:44:48 +0000[diff] [blame]2692<p>Metadata can be used as function arguments. Here <tt>llvm.dbg.value</tt>
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2693 function is using two metadata arguments.</p>
Devang Patel9984bd62010-03-04 23:44:48 +0000[diff] [blame]2694
Bill Wendlingc0e10672011-03-02 02:17:11 +0000[diff] [blame]2695<div class="doc_code">
2696<pre>
2697call void @llvm.dbg.value(metadata !24, i64 0, metadata !25)
2698</pre>
2699</div>
Devang Patel9984bd62010-03-04 23:44:48 +0000[diff] [blame]2700
2701<p>Metadata can be attached with an instruction. Here metadata <tt>!21</tt> is
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2702 attached with <tt>add</tt> instruction using <tt>!dbg</tt> identifier.</p>
Devang Patel9984bd62010-03-04 23:44:48 +0000[diff] [blame]2703
Bill Wendlingc0e10672011-03-02 02:17:11 +0000[diff] [blame]2704<div class="doc_code">
2705<pre>
2706%indvar.next = add i64 %indvar, 1, !dbg !21
2707</pre>
2708</div>
2709
Chris Lattnerc2f8f162010-01-15 21:50:19 +0000[diff] [blame]2710</div>
2711
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]2712
2713<!-- *********************************************************************** -->
2714<div class="doc_section">
2715 <a name="intrinsic_globals">Intrinsic Global Variables</a>
2716</div>
2717<!-- *********************************************************************** -->
2718
2719<p>LLVM has a number of "magic" global variables that contain data that affect
2720code generation or other IR semantics. These are documented here. All globals
Chris Lattner58f9bb22009-07-20 06:14:25 +0000[diff] [blame]2721of this sort should have a section specified as "<tt>llvm.metadata</tt>". This
2722section and all globals that start with "<tt>llvm.</tt>" are reserved for use
2723by LLVM.</p>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]2724
2725<!-- ======================================================================= -->
2726<div class="doc_subsection">
2727<a name="intg_used">The '<tt>llvm.used</tt>' Global Variable</a>
2728</div>
2729
2730<div class="doc_text">
2731
2732<p>The <tt>@llvm.used</tt> global is an array with i8* element type which has <a
2733href="#linkage_appending">appending linkage</a>. This array contains a list of
2734pointers to global variables and functions which may optionally have a pointer
2735cast formed of bitcast or getelementptr. For example, a legal use of it is:</p>
2736
2737<pre>
2738 @X = global i8 4
2739 @Y = global i32 123
2740
2741 @llvm.used = appending global [2 x i8*] [
2742 i8* @X,
2743 i8* bitcast (i32* @Y to i8*)
2744 ], section "llvm.metadata"
2745</pre>
2746
2747<p>If a global variable appears in the <tt>@llvm.used</tt> list, then the
2748compiler, assembler, and linker are required to treat the symbol as if there is
2749a reference to the global that it cannot see. For example, if a variable has
2750internal linkage and no references other than that from the <tt>@llvm.used</tt>
2751list, it cannot be deleted. This is commonly used to represent references from
2752inline asms and other things the compiler cannot "see", and corresponds to
2753"attribute((used))" in GNU C.</p>
2754
2755<p>On some targets, the code generator must emit a directive to the assembler or
2756object file to prevent the assembler and linker from molesting the symbol.</p>
2757
2758</div>
2759
2760<!-- ======================================================================= -->
2761<div class="doc_subsection">
Chris Lattner58f9bb22009-07-20 06:14:25 +0000[diff] [blame]2762<a name="intg_compiler_used">The '<tt>llvm.compiler.used</tt>' Global Variable</a>
2763</div>
2764
2765<div class="doc_text">
2766
2767<p>The <tt>@llvm.compiler.used</tt> directive is the same as the
2768<tt>@llvm.used</tt> directive, except that it only prevents the compiler from
2769touching the symbol. On targets that support it, this allows an intelligent
2770linker to optimize references to the symbol without being impeded as it would be
2771by <tt>@llvm.used</tt>.</p>
2772
2773<p>This is a rare construct that should only be used in rare circumstances, and
2774should not be exposed to source languages.</p>
2775
2776</div>
2777
2778<!-- ======================================================================= -->
2779<div class="doc_subsection">
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]2780<a name="intg_global_ctors">The '<tt>llvm.global_ctors</tt>' Global Variable</a>
2781</div>
2782
2783<div class="doc_text">
David Chisnalla9d4a6f2010-04-30 19:23:49 +0000[diff] [blame]2784<pre>
2785%0 = type { i32, void ()* }
David Chisnallb492b812010-04-30 19:27:35 +0000[diff] [blame]2786@llvm.global_ctors = appending global [1 x %0] [%0 { i32 65535, void ()* @ctor }]
David Chisnalla9d4a6f2010-04-30 19:23:49 +0000[diff] [blame]2787</pre>
2788<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.
2789</p>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]2790
2791</div>
2792
2793<!-- ======================================================================= -->
2794<div class="doc_subsection">
2795<a name="intg_global_dtors">The '<tt>llvm.global_dtors</tt>' Global Variable</a>
2796</div>
2797
2798<div class="doc_text">
David Chisnalla9d4a6f2010-04-30 19:23:49 +0000[diff] [blame]2799<pre>
2800%0 = type { i32, void ()* }
David Chisnallb492b812010-04-30 19:27:35 +0000[diff] [blame]2801@llvm.global_dtors = appending global [1 x %0] [%0 { i32 65535, void ()* @dtor }]
David Chisnalla9d4a6f2010-04-30 19:23:49 +0000[diff] [blame]2802</pre>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]2803
David Chisnalla9d4a6f2010-04-30 19:23:49 +0000[diff] [blame]2804<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.
2805</p>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]2806
2807</div>
2808
2809
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2810<!-- *********************************************************************** -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2811<div class="doc_section"> <a name="instref">Instruction Reference</a> </div>
2812<!-- *********************************************************************** -->
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2813
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2814<div class="doc_text">
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2815
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2816<p>The LLVM instruction set consists of several different classifications of
2817 instructions: <a href="#terminators">terminator
2818 instructions</a>, <a href="#binaryops">binary instructions</a>,
2819 <a href="#bitwiseops">bitwise binary instructions</a>,
2820 <a href="#memoryops">memory instructions</a>, and
2821 <a href="#otherops">other instructions</a>.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2822
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2823</div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2824
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2825<!-- ======================================================================= -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2826<div class="doc_subsection"> <a name="terminators">Terminator
2827Instructions</a> </div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2828
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2829<div class="doc_text">
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2830
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2831<p>As mentioned <a href="#functionstructure">previously</a>, every basic block
2832 in a program ends with a "Terminator" instruction, which indicates which
2833 block should be executed after the current block is finished. These
2834 terminator instructions typically yield a '<tt>void</tt>' value: they produce
2835 control flow, not values (the one exception being the
2836 '<a href="#i_invoke"><tt>invoke</tt></a>' instruction).</p>
2837
Duncan Sands626b0242010-04-15 20:35:54 +0000[diff] [blame]2838<p>There are seven different terminator instructions: the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2839 '<a href="#i_ret"><tt>ret</tt></a>' instruction, the
2840 '<a href="#i_br"><tt>br</tt></a>' instruction, the
2841 '<a href="#i_switch"><tt>switch</tt></a>' instruction, the
Bill Wendling33fef7e2009-11-02 00:25:26 +0000[diff] [blame]2842 '<a href="#i_indirectbr">'<tt>indirectbr</tt></a>' Instruction, the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2843 '<a href="#i_invoke"><tt>invoke</tt></a>' instruction, the
2844 '<a href="#i_unwind"><tt>unwind</tt></a>' instruction, and the
2845 '<a href="#i_unreachable"><tt>unreachable</tt></a>' instruction.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2846
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2847</div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2848
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2849<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2850<div class="doc_subsubsection"> <a name="i_ret">'<tt>ret</tt>'
2851Instruction</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2852
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2853<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2854
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2855<h5>Syntax:</h5>
Dan Gohmancc3132e2008-10-04 19:00:07 +0000[diff] [blame]2856<pre>
2857 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]2858 ret void <i>; Return from void function</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2859</pre>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]2860
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2861<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2862<p>The '<tt>ret</tt>' instruction is used to return control flow (and optionally
2863 a value) from a function back to the caller.</p>
2864
2865<p>There are two forms of the '<tt>ret</tt>' instruction: one that returns a
2866 value and then causes control flow, and one that just causes control flow to
2867 occur.</p>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]2868
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2869<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2870<p>The '<tt>ret</tt>' instruction optionally accepts a single argument, the
2871 return value. The type of the return value must be a
2872 '<a href="#t_firstclass">first class</a>' type.</p>
Dan Gohmancc3132e2008-10-04 19:00:07 +0000[diff] [blame]2873
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2874<p>A function is not <a href="#wellformed">well formed</a> if it it has a
2875 non-void return type and contains a '<tt>ret</tt>' instruction with no return
2876 value or a return value with a type that does not match its type, or if it
2877 has a void return type and contains a '<tt>ret</tt>' instruction with a
2878 return value.</p>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]2879
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2880<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2881<p>When the '<tt>ret</tt>' instruction is executed, control flow returns back to
2882 the calling function's context. If the caller is a
2883 "<a href="#i_call"><tt>call</tt></a>" instruction, execution continues at the
2884 instruction after the call. If the caller was an
2885 "<a href="#i_invoke"><tt>invoke</tt></a>" instruction, execution continues at
2886 the beginning of the "normal" destination block. If the instruction returns
2887 a value, that value shall set the call or invoke instruction's return
2888 value.</p>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]2889
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2890<h5>Example:</h5>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]2891<pre>
2892 ret i32 5 <i>; Return an integer value of 5</i>
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]2893 ret void <i>; Return from a void function</i>
Bill Wendling050ee8f2009-02-28 22:12:54 +0000[diff] [blame]2894 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]2895</pre>
Dan Gohman3065b612009-01-12 23:12:39 +0000[diff] [blame]2896
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2897</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2898<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2899<div class="doc_subsubsection"> <a name="i_br">'<tt>br</tt>' Instruction</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2900
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2901<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2902
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2903<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2904<pre>
2905 br i1 &lt;cond&gt;, label &lt;iftrue&gt;, label &lt;iffalse&gt;<br> br label &lt;dest&gt; <i>; Unconditional branch</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2906</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2907
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2908<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2909<p>The '<tt>br</tt>' instruction is used to cause control flow to transfer to a
2910 different basic block in the current function. There are two forms of this
2911 instruction, corresponding to a conditional branch and an unconditional
2912 branch.</p>
2913
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2914<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2915<p>The conditional branch form of the '<tt>br</tt>' instruction takes a single
2916 '<tt>i1</tt>' value and two '<tt>label</tt>' values. The unconditional form
2917 of the '<tt>br</tt>' instruction takes a single '<tt>label</tt>' value as a
2918 target.</p>
2919
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2920<h5>Semantics:</h5>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]2921<p>Upon execution of a conditional '<tt>br</tt>' instruction, the '<tt>i1</tt>'
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2922 argument is evaluated. If the value is <tt>true</tt>, control flows to the
2923 '<tt>iftrue</tt>' <tt>label</tt> argument. If "cond" is <tt>false</tt>,
2924 control flows to the '<tt>iffalse</tt>' <tt>label</tt> argument.</p>
2925
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2926<h5>Example:</h5>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]2927<pre>
2928Test:
2929 %cond = <a href="#i_icmp">icmp</a> eq i32 %a, %b
2930 br i1 %cond, label %IfEqual, label %IfUnequal
2931IfEqual:
2932 <a href="#i_ret">ret</a> i32 1
2933IfUnequal:
2934 <a href="#i_ret">ret</a> i32 0
2935</pre>
2936
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2937</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2938
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2939<!-- _______________________________________________________________________ -->
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2940<div class="doc_subsubsection">
2941 <a name="i_switch">'<tt>switch</tt>' Instruction</a>
2942</div>
2943
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2944<div class="doc_text">
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2945
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2946<h5>Syntax:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2947<pre>
2948 switch &lt;intty&gt; &lt;value&gt;, label &lt;defaultdest&gt; [ &lt;intty&gt; &lt;val&gt;, label &lt;dest&gt; ... ]
2949</pre>
2950
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2951<h5>Overview:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2952<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]2953 several different places. It is a generalization of the '<tt>br</tt>'
2954 instruction, allowing a branch to occur to one of many possible
2955 destinations.</p>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2956
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2957<h5>Arguments:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2958<p>The '<tt>switch</tt>' instruction uses three parameters: an integer
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2959 comparison value '<tt>value</tt>', a default '<tt>label</tt>' destination,
2960 and an array of pairs of comparison value constants and '<tt>label</tt>'s.
2961 The table is not allowed to contain duplicate constant entries.</p>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2962
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2963<h5>Semantics:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2964<p>The <tt>switch</tt> instruction specifies a table of values and
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2965 destinations. When the '<tt>switch</tt>' instruction is executed, this table
2966 is searched for the given value. If the value is found, control flow is
Benjamin Kramer0f420382009-10-12 14:46:08 +0000[diff] [blame]2967 transferred to the corresponding destination; otherwise, control flow is
2968 transferred to the default destination.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2969
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2970<h5>Implementation:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2971<p>Depending on properties of the target machine and the particular
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2972 <tt>switch</tt> instruction, this instruction may be code generated in
2973 different ways. For example, it could be generated as a series of chained
2974 conditional branches or with a lookup table.</p>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2975
2976<h5>Example:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2977<pre>
2978 <i>; Emulate a conditional br instruction</i>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]2979 %Val = <a href="#i_zext">zext</a> i1 %value to i32
Dan Gohman623806e2009-01-04 23:44:43 +0000[diff] [blame]2980 switch i32 %Val, label %truedest [ i32 0, label %falsedest ]
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2981
2982 <i>; Emulate an unconditional br instruction</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2983 switch i32 0, label %dest [ ]
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2984
2985 <i>; Implement a jump table:</i>
Dan Gohman623806e2009-01-04 23:44:43 +0000[diff] [blame]2986 switch i32 %val, label %otherwise [ i32 0, label %onzero
2987 i32 1, label %onone
2988 i32 2, label %ontwo ]
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2989</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2990
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2991</div>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]2992
Chris Lattner3ed871f2009-10-27 19:13:16 +0000[diff] [blame]2993
2994<!-- _______________________________________________________________________ -->
2995<div class="doc_subsubsection">
Chris Lattnerd04cb6d2009-10-28 00:19:10 +0000[diff] [blame]2996 <a name="i_indirectbr">'<tt>indirectbr</tt>' Instruction</a>
Chris Lattner3ed871f2009-10-27 19:13:16 +0000[diff] [blame]2997</div>
2998
2999<div class="doc_text">
3000
3001<h5>Syntax:</h5>
3002<pre>
Chris Lattnerd04cb6d2009-10-28 00:19:10 +0000[diff] [blame]3003 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]3004</pre>
3005
3006<h5>Overview:</h5>
3007
Chris Lattnerd04cb6d2009-10-28 00:19:10 +0000[diff] [blame]3008<p>The '<tt>indirectbr</tt>' instruction implements an indirect branch to a label
Chris Lattner3ed871f2009-10-27 19:13:16 +0000[diff] [blame]3009 within the current function, whose address is specified by
Chris Lattnere4801f72009-10-27 21:01:34 +0000[diff] [blame]3010 "<tt>address</tt>". Address must be derived from a <a
3011 href="#blockaddress">blockaddress</a> constant.</p>
Chris Lattner3ed871f2009-10-27 19:13:16 +0000[diff] [blame]3012
3013<h5>Arguments:</h5>
3014
3015<p>The '<tt>address</tt>' argument is the address of the label to jump to. The
3016 rest of the arguments indicate the full set of possible destinations that the
3017 address may point to. Blocks are allowed to occur multiple times in the
3018 destination list, though this isn't particularly useful.</p>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3019
Chris Lattner3ed871f2009-10-27 19:13:16 +0000[diff] [blame]3020<p>This destination list is required so that dataflow analysis has an accurate
3021 understanding of the CFG.</p>
3022
3023<h5>Semantics:</h5>
3024
3025<p>Control transfers to the block specified in the address argument. All
3026 possible destination blocks must be listed in the label list, otherwise this
3027 instruction has undefined behavior. This implies that jumps to labels
3028 defined in other functions have undefined behavior as well.</p>
3029
3030<h5>Implementation:</h5>
3031
3032<p>This is typically implemented with a jump through a register.</p>
3033
3034<h5>Example:</h5>
3035<pre>
Chris Lattnerd04cb6d2009-10-28 00:19:10 +0000[diff] [blame]3036 indirectbr i8* %Addr, [ label %bb1, label %bb2, label %bb3 ]
Chris Lattner3ed871f2009-10-27 19:13:16 +0000[diff] [blame]3037</pre>
3038
3039</div>
3040
3041
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3042<!-- _______________________________________________________________________ -->
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3043<div class="doc_subsubsection">
3044 <a name="i_invoke">'<tt>invoke</tt>' Instruction</a>
3045</div>
3046
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3047<div class="doc_text">
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3048
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3049<h5>Syntax:</h5>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3050<pre>
Devang Patel02256232008-10-07 17:48:33 +0000[diff] [blame]3051 &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]3052 to label &lt;normal label&gt; unwind label &lt;exception label&gt;
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3053</pre>
3054
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]3055<h5>Overview:</h5>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3056<p>The '<tt>invoke</tt>' instruction causes control to transfer to a specified
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3057 function, with the possibility of control flow transfer to either the
3058 '<tt>normal</tt>' label or the '<tt>exception</tt>' label. If the callee
3059 function returns with the "<tt><a href="#i_ret">ret</a></tt>" instruction,
3060 control flow will return to the "normal" label. If the callee (or any
3061 indirect callees) returns with the "<a href="#i_unwind"><tt>unwind</tt></a>"
3062 instruction, control is interrupted and continued at the dynamically nearest
3063 "exception" label.</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3064
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3065<h5>Arguments:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3066<p>This instruction requires several arguments:</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3067
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3068<ol>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3069 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
3070 convention</a> the call should use. If none is specified, the call
3071 defaults to using C calling conventions.</li>
Devang Patel7e9b05e2008-10-06 18:50:38 +0000[diff] [blame]3072
3073 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3074 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
3075 '<tt>inreg</tt>' attributes are valid here.</li>
Devang Patel7e9b05e2008-10-06 18:50:38 +0000[diff] [blame]3076
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3077 <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]3078 function value being invoked. In most cases, this is a direct function
3079 invocation, but indirect <tt>invoke</tt>s are just as possible, branching
3080 off an arbitrary pointer to function value.</li>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3081
3082 <li>'<tt>function ptr val</tt>': An LLVM value containing a pointer to a
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3083 function to be invoked. </li>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3084
3085 <li>'<tt>function args</tt>': argument list whose types match the function
Chris Lattner47f2a832010-03-02 06:36:51 +0000[diff] [blame]3086 signature argument types and parameter attributes. All arguments must be
3087 of <a href="#t_firstclass">first class</a> type. If the function
3088 signature indicates the function accepts a variable number of arguments,
3089 the extra arguments can be specified.</li>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3090
3091 <li>'<tt>normal label</tt>': the label reached when the called function
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3092 executes a '<tt><a href="#i_ret">ret</a></tt>' instruction. </li>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3093
3094 <li>'<tt>exception label</tt>': the label reached when a callee returns with
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3095 the <a href="#i_unwind"><tt>unwind</tt></a> instruction. </li>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3096
Devang Patel02256232008-10-07 17:48:33 +0000[diff] [blame]3097 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3098 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
3099 '<tt>readnone</tt>' attributes are valid here.</li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3100</ol>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3101
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3102<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3103<p>This instruction is designed to operate as a standard
3104 '<tt><a href="#i_call">call</a></tt>' instruction in most regards. The
3105 primary difference is that it establishes an association with a label, which
3106 is used by the runtime library to unwind the stack.</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3107
3108<p>This instruction is used in languages with destructors to ensure that proper
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3109 cleanup is performed in the case of either a <tt>longjmp</tt> or a thrown
3110 exception. Additionally, this is important for implementation of
3111 '<tt>catch</tt>' clauses in high-level languages that support them.</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3112
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3113<p>For the purposes of the SSA form, the definition of the value returned by the
3114 '<tt>invoke</tt>' instruction is deemed to occur on the edge from the current
3115 block to the "normal" label. If the callee unwinds then no return value is
3116 available.</p>
Dan Gohman9069d892009-05-22 21:47:08 +0000[diff] [blame]3117
Chris Lattner97257f82010-01-15 18:08:37 +0000[diff] [blame]3118<p>Note that the code generator does not yet completely support unwind, and
3119that the invoke/unwind semantics are likely to change in future versions.</p>
3120
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3121<h5>Example:</h5>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3122<pre>
Nick Lewycky084ab472008-03-16 07:18:12 +0000[diff] [blame]3123 %retval = invoke i32 @Test(i32 15) to label %Continue
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]3124 unwind label %TestCleanup <i>; {i32}:retval set</i>
Nick Lewycky084ab472008-03-16 07:18:12 +0000[diff] [blame]3125 %retval = invoke <a href="#callingconv">coldcc</a> i32 %Testfnptr(i32 15) to label %Continue
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]3126 unwind label %TestCleanup <i>; {i32}:retval set</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3127</pre>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3128
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3129</div>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3130
Chris Lattner5ed60612003-09-03 00:41:47 +0000[diff] [blame]3131<!-- _______________________________________________________________________ -->
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3132
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3133<div class="doc_subsubsection"> <a name="i_unwind">'<tt>unwind</tt>'
3134Instruction</a> </div>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3135
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3136<div class="doc_text">
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3137
Chris Lattner5ed60612003-09-03 00:41:47 +0000[diff] [blame]3138<h5>Syntax:</h5>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3139<pre>
3140 unwind
3141</pre>
3142
Chris Lattner5ed60612003-09-03 00:41:47 +0000[diff] [blame]3143<h5>Overview:</h5>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3144<p>The '<tt>unwind</tt>' instruction unwinds the stack, continuing control flow
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3145 at the first callee in the dynamic call stack which used
3146 an <a href="#i_invoke"><tt>invoke</tt></a> instruction to perform the call.
3147 This is primarily used to implement exception handling.</p>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3148
Chris Lattner5ed60612003-09-03 00:41:47 +0000[diff] [blame]3149<h5>Semantics:</h5>
Chris Lattnerfe8519c2008-04-19 21:01:16 +0000[diff] [blame]3150<p>The '<tt>unwind</tt>' instruction causes execution of the current function to
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3151 immediately halt. The dynamic call stack is then searched for the
3152 first <a href="#i_invoke"><tt>invoke</tt></a> instruction on the call stack.
3153 Once found, execution continues at the "exceptional" destination block
3154 specified by the <tt>invoke</tt> instruction. If there is no <tt>invoke</tt>
3155 instruction in the dynamic call chain, undefined behavior results.</p>
3156
Chris Lattner97257f82010-01-15 18:08:37 +0000[diff] [blame]3157<p>Note that the code generator does not yet completely support unwind, and
3158that the invoke/unwind semantics are likely to change in future versions.</p>
3159
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3160</div>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3161
3162<!-- _______________________________________________________________________ -->
3163
3164<div class="doc_subsubsection"> <a name="i_unreachable">'<tt>unreachable</tt>'
3165Instruction</a> </div>
3166
3167<div class="doc_text">
3168
3169<h5>Syntax:</h5>
3170<pre>
3171 unreachable
3172</pre>
3173
3174<h5>Overview:</h5>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3175<p>The '<tt>unreachable</tt>' instruction has no defined semantics. This
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3176 instruction is used to inform the optimizer that a particular portion of the
3177 code is not reachable. This can be used to indicate that the code after a
3178 no-return function cannot be reached, and other facts.</p>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3179
3180<h5>Semantics:</h5>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3181<p>The '<tt>unreachable</tt>' instruction has no defined semantics.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3182
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3183</div>
3184
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3185<!-- ======================================================================= -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3186<div class="doc_subsection"> <a name="binaryops">Binary Operations</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3187
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3188<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3189
3190<p>Binary operators are used to do most of the computation in a program. They
3191 require two operands of the same type, execute an operation on them, and
3192 produce a single value. The operands might represent multiple data, as is
3193 the case with the <a href="#t_vector">vector</a> data type. The result value
3194 has the same type as its operands.</p>
3195
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3196<p>There are several different binary operators:</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3197
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3198</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3199
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3200<!-- _______________________________________________________________________ -->
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3201<div class="doc_subsubsection">
3202 <a name="i_add">'<tt>add</tt>' Instruction</a>
3203</div>
3204
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3205<div class="doc_text">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3206
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3207<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3208<pre>
Dan Gohmanb07de442009-07-20 22:41:19 +0000[diff] [blame]3209 &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]3210 &lt;result&gt; = add nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3211 &lt;result&gt; = add nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3212 &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]3213</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3214
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3215<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3216<p>The '<tt>add</tt>' instruction returns the sum of its two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3217
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3218<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3219<p>The two arguments to the '<tt>add</tt>' instruction must
3220 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3221 integer values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3222
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3223<h5>Semantics:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3224<p>The value produced is the integer sum of the two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3225
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3226<p>If the sum has unsigned overflow, the result returned is the mathematical
3227 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]3228
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3229<p>Because LLVM integers use a two's complement representation, this instruction
3230 is appropriate for both signed and unsigned integers.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3231
Dan Gohman902dfff2009-07-22 22:44:56 +0000[diff] [blame]3232<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3233 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3234 <tt>nsw</tt> keywords are present, the result value of the <tt>add</tt>
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]3235 is a <a href="#trapvalues">trap value</a> if unsigned and/or signed overflow,
3236 respectively, occurs.</p>
Dan Gohmanb07de442009-07-20 22:41:19 +0000[diff] [blame]3237
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3238<h5>Example:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3239<pre>
3240 &lt;result&gt; = add i32 4, %var <i>; yields {i32}:result = 4 + %var</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3241</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3242
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3243</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3244
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3245<!-- _______________________________________________________________________ -->
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3246<div class="doc_subsubsection">
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3247 <a name="i_fadd">'<tt>fadd</tt>' Instruction</a>
3248</div>
3249
3250<div class="doc_text">
3251
3252<h5>Syntax:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3253<pre>
3254 &lt;result&gt; = fadd &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3255</pre>
3256
3257<h5>Overview:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3258<p>The '<tt>fadd</tt>' instruction returns the sum of its two operands.</p>
3259
3260<h5>Arguments:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3261<p>The two arguments to the '<tt>fadd</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3262 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3263 floating point values. Both arguments must have identical types.</p>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3264
3265<h5>Semantics:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3266<p>The value produced is the floating point sum of the two operands.</p>
3267
3268<h5>Example:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3269<pre>
3270 &lt;result&gt; = fadd float 4.0, %var <i>; yields {float}:result = 4.0 + %var</i>
3271</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3272
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3273</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3274
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3275<!-- _______________________________________________________________________ -->
3276<div class="doc_subsubsection">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3277 <a name="i_sub">'<tt>sub</tt>' Instruction</a>
3278</div>
3279
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3280<div class="doc_text">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3281
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3282<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3283<pre>
Dan Gohman902dfff2009-07-22 22:44:56 +0000[diff] [blame]3284 &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]3285 &lt;result&gt; = sub nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3286 &lt;result&gt; = sub nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3287 &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]3288</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3289
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3290<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3291<p>The '<tt>sub</tt>' instruction returns the difference of its two
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3292 operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3293
3294<p>Note that the '<tt>sub</tt>' instruction is used to represent the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3295 '<tt>neg</tt>' instruction present in most other intermediate
3296 representations.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3297
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3298<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3299<p>The two arguments to the '<tt>sub</tt>' instruction must
3300 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3301 integer values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3302
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3303<h5>Semantics:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3304<p>The value produced is the integer difference of the two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3305
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3306<p>If the difference has unsigned overflow, the result returned is the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3307 mathematical result modulo 2<sup>n</sup>, where n is the bit width of the
3308 result.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3309
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3310<p>Because LLVM integers use a two's complement representation, this instruction
3311 is appropriate for both signed and unsigned integers.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3312
Dan Gohman902dfff2009-07-22 22:44:56 +0000[diff] [blame]3313<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3314 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3315 <tt>nsw</tt> keywords are present, the result value of the <tt>sub</tt>
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]3316 is a <a href="#trapvalues">trap value</a> if unsigned and/or signed overflow,
3317 respectively, occurs.</p>
Dan Gohmanb07de442009-07-20 22:41:19 +0000[diff] [blame]3318
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3319<h5>Example:</h5>
Bill Wendling2d8b9a82007-05-29 09:42:13 +0000[diff] [blame]3320<pre>
3321 &lt;result&gt; = sub i32 4, %var <i>; yields {i32}:result = 4 - %var</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3322 &lt;result&gt; = sub i32 0, %val <i>; yields {i32}:result = -%var</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3323</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3324
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3325</div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3326
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3327<!-- _______________________________________________________________________ -->
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3328<div class="doc_subsubsection">
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3329 <a name="i_fsub">'<tt>fsub</tt>' Instruction</a>
3330</div>
3331
3332<div class="doc_text">
3333
3334<h5>Syntax:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3335<pre>
3336 &lt;result&gt; = fsub &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3337</pre>
3338
3339<h5>Overview:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3340<p>The '<tt>fsub</tt>' instruction returns the difference of its two
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3341 operands.</p>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3342
3343<p>Note that the '<tt>fsub</tt>' instruction is used to represent the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3344 '<tt>fneg</tt>' instruction present in most other intermediate
3345 representations.</p>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3346
3347<h5>Arguments:</h5>
Bill Wendling972b7202009-07-20 02:32:41 +0000[diff] [blame]3348<p>The two arguments to the '<tt>fsub</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3349 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3350 floating point values. Both arguments must have identical types.</p>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3351
3352<h5>Semantics:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3353<p>The value produced is the floating point difference of the two operands.</p>
3354
3355<h5>Example:</h5>
3356<pre>
3357 &lt;result&gt; = fsub float 4.0, %var <i>; yields {float}:result = 4.0 - %var</i>
3358 &lt;result&gt; = fsub float -0.0, %val <i>; yields {float}:result = -%var</i>
3359</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3360
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3361</div>
3362
3363<!-- _______________________________________________________________________ -->
3364<div class="doc_subsubsection">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3365 <a name="i_mul">'<tt>mul</tt>' Instruction</a>
3366</div>
3367
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3368<div class="doc_text">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3369
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3370<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3371<pre>
Dan Gohman902dfff2009-07-22 22:44:56 +0000[diff] [blame]3372 &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]3373 &lt;result&gt; = mul nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3374 &lt;result&gt; = mul nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3375 &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]3376</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3377
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3378<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3379<p>The '<tt>mul</tt>' instruction returns the product of its two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3380
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3381<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3382<p>The two arguments to the '<tt>mul</tt>' instruction must
3383 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3384 integer values. Both arguments must have identical types.</p>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3385
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3386<h5>Semantics:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3387<p>The value produced is the integer product of the two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3388
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3389<p>If the result of the multiplication has unsigned overflow, the result
3390 returned is the mathematical result modulo 2<sup>n</sup>, where n is the bit
3391 width of the result.</p>
3392
3393<p>Because LLVM integers use a two's complement representation, and the result
3394 is the same width as the operands, this instruction returns the correct
3395 result for both signed and unsigned integers. If a full product
3396 (e.g. <tt>i32</tt>x<tt>i32</tt>-><tt>i64</tt>) is needed, the operands should
3397 be sign-extended or zero-extended as appropriate to the width of the full
3398 product.</p>
3399
Dan Gohman902dfff2009-07-22 22:44:56 +0000[diff] [blame]3400<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3401 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3402 <tt>nsw</tt> keywords are present, the result value of the <tt>mul</tt>
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]3403 is a <a href="#trapvalues">trap value</a> if unsigned and/or signed overflow,
3404 respectively, occurs.</p>
Dan Gohmanb07de442009-07-20 22:41:19 +0000[diff] [blame]3405
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3406<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3407<pre>
3408 &lt;result&gt; = mul i32 4, %var <i>; yields {i32}:result = 4 * %var</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3409</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3410
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3411</div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3412
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3413<!-- _______________________________________________________________________ -->
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3414<div class="doc_subsubsection">
3415 <a name="i_fmul">'<tt>fmul</tt>' Instruction</a>
3416</div>
3417
3418<div class="doc_text">
3419
3420<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3421<pre>
3422 &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]3423</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3424
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3425<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3426<p>The '<tt>fmul</tt>' instruction returns the product of its two operands.</p>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3427
3428<h5>Arguments:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3429<p>The two arguments to the '<tt>fmul</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3430 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3431 floating point values. Both arguments must have identical types.</p>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3432
3433<h5>Semantics:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3434<p>The value produced is the floating point product of the two operands.</p>
3435
3436<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3437<pre>
3438 &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]3439</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3440
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3441</div>
3442
3443<!-- _______________________________________________________________________ -->
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3444<div class="doc_subsubsection"> <a name="i_udiv">'<tt>udiv</tt>' Instruction
3445</a></div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3446
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3447<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3448
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3449<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3450<pre>
Chris Lattner35315d02011-02-06 21:44:57 +0000[diff] [blame]3451 &lt;result&gt; = udiv &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3452 &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]3453</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3454
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3455<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3456<p>The '<tt>udiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3457
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3458<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3459<p>The two arguments to the '<tt>udiv</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3460 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3461 values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3462
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3463<h5>Semantics:</h5>
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3464<p>The value produced is the unsigned integer quotient of the two operands.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3465
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3466<p>Note that unsigned integer division and signed integer division are distinct
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3467 operations; for signed integer division, use '<tt>sdiv</tt>'.</p>
3468
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3469<p>Division by zero leads to undefined behavior.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3470
Chris Lattner35315d02011-02-06 21:44:57 +0000[diff] [blame]3471<p>If the <tt>exact</tt> keyword is present, the result value of the
3472 <tt>udiv</tt> is a <a href="#trapvalues">trap value</a> if %op1 is not a
3473 multiple of %op2 (as such, "((a udiv exact b) mul b) == a").</p>
3474
3475
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3476<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3477<pre>
3478 &lt;result&gt; = udiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3479</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3480
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3481</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3482
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3483<!-- _______________________________________________________________________ -->
3484<div class="doc_subsubsection"> <a name="i_sdiv">'<tt>sdiv</tt>' Instruction
3485</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3486
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3487<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3488
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3489<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3490<pre>
Dan Gohmanb07de442009-07-20 22:41:19 +0000[diff] [blame]3491 &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]3492 &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]3493</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3494
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3495<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3496<p>The '<tt>sdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3497
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3498<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3499<p>The two arguments to the '<tt>sdiv</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3500 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3501 values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3502
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3503<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3504<p>The value produced is the signed integer quotient of the two operands rounded
3505 towards zero.</p>
3506
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3507<p>Note that signed integer division and unsigned integer division are distinct
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3508 operations; for unsigned integer division, use '<tt>udiv</tt>'.</p>
3509
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3510<p>Division by zero leads to undefined behavior. Overflow also leads to
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3511 undefined behavior; this is a rare case, but can occur, for example, by doing
3512 a 32-bit division of -2147483648 by -1.</p>
3513
Dan Gohman71dfd782009-07-22 00:04:19 +0000[diff] [blame]3514<p>If the <tt>exact</tt> keyword is present, the result value of the
Dan Gohman57255802010-04-23 15:23:32 +0000[diff] [blame]3515 <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]3516 be rounded.</p>
Dan Gohmanb07de442009-07-20 22:41:19 +0000[diff] [blame]3517
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3518<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3519<pre>
3520 &lt;result&gt; = sdiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3521</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3522
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3523</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3524
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3525<!-- _______________________________________________________________________ -->
3526<div class="doc_subsubsection"> <a name="i_fdiv">'<tt>fdiv</tt>'
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3527Instruction</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3528
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3529<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3530
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3531<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3532<pre>
Gabor Greif0f75ad02008-08-07 21:46:00 +0000[diff] [blame]3533 &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]3534</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3535
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3536<h5>Overview:</h5>
3537<p>The '<tt>fdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3538
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3539<h5>Arguments:</h5>
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]3540<p>The two arguments to the '<tt>fdiv</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3541 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3542 floating point values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3543
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3544<h5>Semantics:</h5>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3545<p>The value produced is the floating point quotient of the two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3546
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3547<h5>Example:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3548<pre>
3549 &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]3550</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3551
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3552</div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3553
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3554<!-- _______________________________________________________________________ -->
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3555<div class="doc_subsubsection"> <a name="i_urem">'<tt>urem</tt>' Instruction</a>
3556</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3557
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3558<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3559
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3560<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3561<pre>
3562 &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]3563</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3564
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3565<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3566<p>The '<tt>urem</tt>' instruction returns the remainder from the unsigned
3567 division of its two arguments.</p>
3568
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3569<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3570<p>The two arguments to the '<tt>urem</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3571 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3572 values. Both arguments must have identical types.</p>
3573
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3574<h5>Semantics:</h5>
3575<p>This instruction returns the unsigned integer <i>remainder</i> of a division.
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3576 This instruction always performs an unsigned division to get the
3577 remainder.</p>
3578
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3579<p>Note that unsigned integer remainder and signed integer remainder are
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3580 distinct operations; for signed integer remainder, use '<tt>srem</tt>'.</p>
3581
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3582<p>Taking the remainder of a division by zero leads to undefined behavior.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3583
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3584<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3585<pre>
3586 &lt;result&gt; = urem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3587</pre>
3588
3589</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3590
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3591<!-- _______________________________________________________________________ -->
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3592<div class="doc_subsubsection">
3593 <a name="i_srem">'<tt>srem</tt>' Instruction</a>
3594</div>
3595
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3596<div class="doc_text">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3597
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3598<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3599<pre>
Gabor Greif0f75ad02008-08-07 21:46:00 +0000[diff] [blame]3600 &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]3601</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3602
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3603<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3604<p>The '<tt>srem</tt>' instruction returns the remainder from the signed
3605 division of its two operands. This instruction can also take
3606 <a href="#t_vector">vector</a> versions of the values in which case the
3607 elements must be integers.</p>
Chris Lattnerb8f816e2008-01-04 04:33:49 +0000[diff] [blame]3608
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3609<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3610<p>The two arguments to the '<tt>srem</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3611 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3612 values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3613
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3614<h5>Semantics:</h5>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3615<p>This instruction returns the <i>remainder</i> of a division (where the result
Duncan Sands2769c6e2011-03-07 09:12:24 +0000[diff] [blame]3616 is either zero or has the same sign as the dividend, <tt>op1</tt>), not the
3617 <i>modulo</i> operator (where the result is either zero or has the same sign
3618 as the divisor, <tt>op2</tt>) of a value.
3619 For more information about the difference,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3620 see <a href="http://mathforum.org/dr.math/problems/anne.4.28.99.html">The
3621 Math Forum</a>. For a table of how this is implemented in various languages,
3622 please see <a href="http://en.wikipedia.org/wiki/Modulo_operation">
3623 Wikipedia: modulo operation</a>.</p>
3624
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3625<p>Note that signed integer remainder and unsigned integer remainder are
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3626 distinct operations; for unsigned integer remainder, use '<tt>urem</tt>'.</p>
3627
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3628<p>Taking the remainder of a division by zero leads to undefined behavior.
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3629 Overflow also leads to undefined behavior; this is a rare case, but can
3630 occur, for example, by taking the remainder of a 32-bit division of
3631 -2147483648 by -1. (The remainder doesn't actually overflow, but this rule
3632 lets srem be implemented using instructions that return both the result of
3633 the division and the remainder.)</p>
3634
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3635<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3636<pre>
3637 &lt;result&gt; = srem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3638</pre>
3639
3640</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3641
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3642<!-- _______________________________________________________________________ -->
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3643<div class="doc_subsubsection">
3644 <a name="i_frem">'<tt>frem</tt>' Instruction</a> </div>
3645
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3646<div class="doc_text">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3647
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3648<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3649<pre>
3650 &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]3651</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3652
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3653<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3654<p>The '<tt>frem</tt>' instruction returns the remainder from the division of
3655 its two operands.</p>
3656
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3657<h5>Arguments:</h5>
3658<p>The two arguments to the '<tt>frem</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3659 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3660 floating point values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3661
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3662<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3663<p>This instruction returns the <i>remainder</i> of a division. The remainder
3664 has the same sign as the dividend.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3665
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3666<h5>Example:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3667<pre>
3668 &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]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>
Robert Bocchino820bc75b2006-02-17 21:18:08 +0000[diff] [blame]3672
Reid Spencer2ab01932007-02-02 13:57:07 +0000[diff] [blame]3673<!-- ======================================================================= -->
3674<div class="doc_subsection"> <a name="bitwiseops">Bitwise Binary
3675Operations</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3676
Reid Spencer2ab01932007-02-02 13:57:07 +0000[diff] [blame]3677<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3678
3679<p>Bitwise binary operators are used to do various forms of bit-twiddling in a
3680 program. They are generally very efficient instructions and can commonly be
3681 strength reduced from other instructions. They require two operands of the
3682 same type, execute an operation on them, and produce a single value. The
3683 resulting value is the same type as its operands.</p>
3684
Reid Spencer2ab01932007-02-02 13:57:07 +0000[diff] [blame]3685</div>
3686
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3687<!-- _______________________________________________________________________ -->
3688<div class="doc_subsubsection"> <a name="i_shl">'<tt>shl</tt>'
3689Instruction</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3690
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3691<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3692
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3693<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3694<pre>
Chris Lattnera676c0f2011-02-07 16:40:21 +0000[diff] [blame]3695 &lt;result&gt; = shl &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3696 &lt;result&gt; = shl nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3697 &lt;result&gt; = shl nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3698 &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]3699</pre>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]3700
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3701<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3702<p>The '<tt>shl</tt>' instruction returns the first operand shifted to the left
3703 a specified number of bits.</p>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]3704
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3705<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3706<p>Both arguments to the '<tt>shl</tt>' instruction must be the
3707 same <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3708 integer type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3709
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3710<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3711<p>The value produced is <tt>op1</tt> * 2<sup><tt>op2</tt></sup> mod
3712 2<sup>n</sup>, where <tt>n</tt> is the width of the result. If <tt>op2</tt>
3713 is (statically or dynamically) negative or equal to or larger than the number
3714 of bits in <tt>op1</tt>, the result is undefined. If the arguments are
3715 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
3716 shift amount in <tt>op2</tt>.</p>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]3717
Chris Lattnera676c0f2011-02-07 16:40:21 +0000[diff] [blame]3718<p>If the <tt>nuw</tt> keyword is present, then the shift produces a
3719 <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]3720 the <tt>nsw</tt> keyword is present, then the shift produces a
Chris Lattnera676c0f2011-02-07 16:40:21 +0000[diff] [blame]3721 <a href="#trapvalues">trap value</a> if it shifts out any bits that disagree
3722 with the resultant sign bit. As such, NUW/NSW have the same semantics as
3723 they would if the shift were expressed as a mul instruction with the same
3724 nsw/nuw bits in (mul %op1, (shl 1, %op2)).</p>
3725
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3726<h5>Example:</h5>
3727<pre>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3728 &lt;result&gt; = shl i32 4, %var <i>; yields {i32}: 4 &lt;&lt; %var</i>
3729 &lt;result&gt; = shl i32 4, 2 <i>; yields {i32}: 16</i>
3730 &lt;result&gt; = shl i32 1, 10 <i>; yields {i32}: 1024</i>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]3731 &lt;result&gt; = shl i32 1, 32 <i>; undefined</i>
Mon P Wang4dd832d2008-12-09 05:46:39 +0000[diff] [blame]3732 &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]3733</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3734
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3735</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3736
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3737<!-- _______________________________________________________________________ -->
3738<div class="doc_subsubsection"> <a name="i_lshr">'<tt>lshr</tt>'
3739Instruction</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3740
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3741<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3742
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3743<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3744<pre>
Chris Lattnera676c0f2011-02-07 16:40:21 +0000[diff] [blame]3745 &lt;result&gt; = lshr &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3746 &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]3747</pre>
3748
3749<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3750<p>The '<tt>lshr</tt>' instruction (logical shift right) returns the first
3751 operand shifted to the right a specified number of bits with zero fill.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3752
3753<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3754<p>Both arguments to the '<tt>lshr</tt>' instruction must be the same
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3755 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3756 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3757
3758<h5>Semantics:</h5>
3759<p>This instruction always performs a logical shift right operation. The most
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3760 significant bits of the result will be filled with zero bits after the shift.
3761 If <tt>op2</tt> is (statically or dynamically) equal to or larger than the
3762 number of bits in <tt>op1</tt>, the result is undefined. If the arguments are
3763 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
3764 shift amount in <tt>op2</tt>.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3765
Chris Lattnera676c0f2011-02-07 16:40:21 +0000[diff] [blame]3766<p>If the <tt>exact</tt> keyword is present, the result value of the
3767 <tt>lshr</tt> is a <a href="#trapvalues">trap value</a> if any of the bits
3768 shifted out are non-zero.</p>
3769
3770
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3771<h5>Example:</h5>
3772<pre>
3773 &lt;result&gt; = lshr i32 4, 1 <i>; yields {i32}:result = 2</i>
3774 &lt;result&gt; = lshr i32 4, 2 <i>; yields {i32}:result = 1</i>
3775 &lt;result&gt; = lshr i8 4, 3 <i>; yields {i8}:result = 0</i>
3776 &lt;result&gt; = lshr i8 -2, 1 <i>; yields {i8}:result = 0x7FFFFFFF </i>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]3777 &lt;result&gt; = lshr i32 1, 32 <i>; undefined</i>
Mon P Wang4dd832d2008-12-09 05:46:39 +0000[diff] [blame]3778 &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]3779</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3780
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3781</div>
3782
Reid Spencer2ab01932007-02-02 13:57:07 +0000[diff] [blame]3783<!-- _______________________________________________________________________ -->
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3784<div class="doc_subsubsection"> <a name="i_ashr">'<tt>ashr</tt>'
3785Instruction</a> </div>
3786<div class="doc_text">
3787
3788<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3789<pre>
Chris Lattnera676c0f2011-02-07 16:40:21 +0000[diff] [blame]3790 &lt;result&gt; = ashr &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3791 &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]3792</pre>
3793
3794<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3795<p>The '<tt>ashr</tt>' instruction (arithmetic shift right) returns the first
3796 operand shifted to the right a specified number of bits with sign
3797 extension.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3798
3799<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3800<p>Both arguments to the '<tt>ashr</tt>' instruction must be the same
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3801 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3802 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3803
3804<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3805<p>This instruction always performs an arithmetic shift right operation, The
3806 most significant bits of the result will be filled with the sign bit
3807 of <tt>op1</tt>. If <tt>op2</tt> is (statically or dynamically) equal to or
3808 larger than the number of bits in <tt>op1</tt>, the result is undefined. If
3809 the arguments are vectors, each vector element of <tt>op1</tt> is shifted by
3810 the corresponding shift amount in <tt>op2</tt>.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3811
Chris Lattnera676c0f2011-02-07 16:40:21 +0000[diff] [blame]3812<p>If the <tt>exact</tt> keyword is present, the result value of the
3813 <tt>ashr</tt> is a <a href="#trapvalues">trap value</a> if any of the bits
3814 shifted out are non-zero.</p>
3815
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3816<h5>Example:</h5>
3817<pre>
3818 &lt;result&gt; = ashr i32 4, 1 <i>; yields {i32}:result = 2</i>
3819 &lt;result&gt; = ashr i32 4, 2 <i>; yields {i32}:result = 1</i>
3820 &lt;result&gt; = ashr i8 4, 3 <i>; yields {i8}:result = 0</i>
3821 &lt;result&gt; = ashr i8 -2, 1 <i>; yields {i8}:result = -1</i>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]3822 &lt;result&gt; = ashr i32 1, 32 <i>; undefined</i>
Mon P Wang4dd832d2008-12-09 05:46:39 +0000[diff] [blame]3823 &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]3824</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3825
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3826</div>
3827
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3828<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3829<div class="doc_subsubsection"> <a name="i_and">'<tt>and</tt>'
3830Instruction</a> </div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3831
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3832<div class="doc_text">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3833
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3834<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3835<pre>
Gabor Greif0f75ad02008-08-07 21:46:00 +0000[diff] [blame]3836 &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]3837</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3838
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3839<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3840<p>The '<tt>and</tt>' instruction returns the bitwise logical and of its two
3841 operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3842
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3843<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3844<p>The two arguments to the '<tt>and</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3845 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3846 values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3847
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3848<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3849<p>The truth table used for the '<tt>and</tt>' instruction is:</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3850
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3851<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3852 <tbody>
3853 <tr>
3854 <td>In0</td>
3855 <td>In1</td>
3856 <td>Out</td>
3857 </tr>
3858 <tr>
3859 <td>0</td>
3860 <td>0</td>
3861 <td>0</td>
3862 </tr>
3863 <tr>
3864 <td>0</td>
3865 <td>1</td>
3866 <td>0</td>
3867 </tr>
3868 <tr>
3869 <td>1</td>
3870 <td>0</td>
3871 <td>0</td>
3872 </tr>
3873 <tr>
3874 <td>1</td>
3875 <td>1</td>
3876 <td>1</td>
3877 </tr>
3878 </tbody>
3879</table>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3880
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3881<h5>Example:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3882<pre>
3883 &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]3884 &lt;result&gt; = and i32 15, 40 <i>; yields {i32}:result = 8</i>
3885 &lt;result&gt; = and i32 4, 8 <i>; yields {i32}:result = 0</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3886</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3887</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3888<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3889<div class="doc_subsubsection"> <a name="i_or">'<tt>or</tt>' Instruction</a> </div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3890
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3891<div class="doc_text">
3892
3893<h5>Syntax:</h5>
3894<pre>
3895 &lt;result&gt; = or &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3896</pre>
3897
3898<h5>Overview:</h5>
3899<p>The '<tt>or</tt>' instruction returns the bitwise logical inclusive or of its
3900 two operands.</p>
3901
3902<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3903<p>The two arguments to the '<tt>or</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3904 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3905 values. Both arguments must have identical types.</p>
3906
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3907<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3908<p>The truth table used for the '<tt>or</tt>' instruction is:</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3909
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3910<table border="1" cellspacing="0" cellpadding="4">
3911 <tbody>
3912 <tr>
3913 <td>In0</td>
3914 <td>In1</td>
3915 <td>Out</td>
3916 </tr>
3917 <tr>
3918 <td>0</td>
3919 <td>0</td>
3920 <td>0</td>
3921 </tr>
3922 <tr>
3923 <td>0</td>
3924 <td>1</td>
3925 <td>1</td>
3926 </tr>
3927 <tr>
3928 <td>1</td>
3929 <td>0</td>
3930 <td>1</td>
3931 </tr>
3932 <tr>
3933 <td>1</td>
3934 <td>1</td>
3935 <td>1</td>
3936 </tr>
3937 </tbody>
3938</table>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3939
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3940<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3941<pre>
3942 &lt;result&gt; = or i32 4, %var <i>; yields {i32}:result = 4 | %var</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3943 &lt;result&gt; = or i32 15, 40 <i>; yields {i32}:result = 47</i>
3944 &lt;result&gt; = or i32 4, 8 <i>; yields {i32}:result = 12</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3945</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3946
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3947</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3948
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3949<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3950<div class="doc_subsubsection"> <a name="i_xor">'<tt>xor</tt>'
3951Instruction</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3952
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3953<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3954
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3955<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3956<pre>
3957 &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]3958</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3959
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3960<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3961<p>The '<tt>xor</tt>' instruction returns the bitwise logical exclusive or of
3962 its two operands. The <tt>xor</tt> is used to implement the "one's
3963 complement" operation, which is the "~" operator in C.</p>
3964
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3965<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3966<p>The two arguments to the '<tt>xor</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3967 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3968 values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3969
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3970<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3971<p>The truth table used for the '<tt>xor</tt>' instruction is:</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3972
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3973<table border="1" cellspacing="0" cellpadding="4">
3974 <tbody>
3975 <tr>
3976 <td>In0</td>
3977 <td>In1</td>
3978 <td>Out</td>
3979 </tr>
3980 <tr>
3981 <td>0</td>
3982 <td>0</td>
3983 <td>0</td>
3984 </tr>
3985 <tr>
3986 <td>0</td>
3987 <td>1</td>
3988 <td>1</td>
3989 </tr>
3990 <tr>
3991 <td>1</td>
3992 <td>0</td>
3993 <td>1</td>
3994 </tr>
3995 <tr>
3996 <td>1</td>
3997 <td>1</td>
3998 <td>0</td>
3999 </tr>
4000 </tbody>
4001</table>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4002
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4003<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4004<pre>
4005 &lt;result&gt; = xor i32 4, %var <i>; yields {i32}:result = 4 ^ %var</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4006 &lt;result&gt; = xor i32 15, 40 <i>; yields {i32}:result = 39</i>
4007 &lt;result&gt; = xor i32 4, 8 <i>; yields {i32}:result = 12</i>
4008 &lt;result&gt; = xor i32 %V, -1 <i>; yields {i32}:result = ~%V</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4009</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4010
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4011</div>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4012
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4013<!-- ======================================================================= -->
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4014<div class="doc_subsection">
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4015 <a name="vectorops">Vector Operations</a>
4016</div>
4017
4018<div class="doc_text">
4019
4020<p>LLVM supports several instructions to represent vector operations in a
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4021 target-independent manner. These instructions cover the element-access and
4022 vector-specific operations needed to process vectors effectively. While LLVM
4023 does directly support these vector operations, many sophisticated algorithms
4024 will want to use target-specific intrinsics to take full advantage of a
4025 specific target.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4026
4027</div>
4028
4029<!-- _______________________________________________________________________ -->
4030<div class="doc_subsubsection">
4031 <a name="i_extractelement">'<tt>extractelement</tt>' Instruction</a>
4032</div>
4033
4034<div class="doc_text">
4035
4036<h5>Syntax:</h5>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4037<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4038 &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]4039</pre>
4040
4041<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4042<p>The '<tt>extractelement</tt>' instruction extracts a single scalar element
4043 from a vector at a specified index.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4044
4045
4046<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4047<p>The first operand of an '<tt>extractelement</tt>' instruction is a value
4048 of <a href="#t_vector">vector</a> type. The second operand is an index
4049 indicating the position from which to extract the element. The index may be
4050 a variable.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4051
4052<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4053<p>The result is a scalar of the same type as the element type of
4054 <tt>val</tt>. Its value is the value at position <tt>idx</tt> of
4055 <tt>val</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
4056 results are undefined.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4057
4058<h5>Example:</h5>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4059<pre>
Gabor Greif03ab4dc2009-10-28 13:14:50 +0000[diff] [blame]4060 &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]4061</pre>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4062
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4063</div>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4064
4065<!-- _______________________________________________________________________ -->
4066<div class="doc_subsubsection">
4067 <a name="i_insertelement">'<tt>insertelement</tt>' Instruction</a>
4068</div>
4069
4070<div class="doc_text">
4071
4072<h5>Syntax:</h5>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4073<pre>
Dan Gohman43ba0672008-05-12 23:38:42 +0000[diff] [blame]4074 &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]4075</pre>
4076
4077<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4078<p>The '<tt>insertelement</tt>' instruction inserts a scalar element into a
4079 vector at a specified index.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4080
4081<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4082<p>The first operand of an '<tt>insertelement</tt>' instruction is a value
4083 of <a href="#t_vector">vector</a> type. The second operand is a scalar value
4084 whose type must equal the element type of the first operand. The third
4085 operand is an index indicating the position at which to insert the value.
4086 The index may be a variable.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4087
4088<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4089<p>The result is a vector of the same type as <tt>val</tt>. Its element values
4090 are those of <tt>val</tt> except at position <tt>idx</tt>, where it gets the
4091 value <tt>elt</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
4092 results are undefined.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4093
4094<h5>Example:</h5>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4095<pre>
Gabor Greif03ab4dc2009-10-28 13:14:50 +0000[diff] [blame]4096 &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]4097</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4098
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4099</div>
4100
4101<!-- _______________________________________________________________________ -->
4102<div class="doc_subsubsection">
4103 <a name="i_shufflevector">'<tt>shufflevector</tt>' Instruction</a>
4104</div>
4105
4106<div class="doc_text">
4107
4108<h5>Syntax:</h5>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4109<pre>
Mon P Wang25f01062008-11-10 04:46:22 +0000[diff] [blame]4110 &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]4111</pre>
4112
4113<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4114<p>The '<tt>shufflevector</tt>' instruction constructs a permutation of elements
4115 from two input vectors, returning a vector with the same element type as the
4116 input and length that is the same as the shuffle mask.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4117
4118<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4119<p>The first two operands of a '<tt>shufflevector</tt>' instruction are vectors
4120 with types that match each other. The third argument is a shuffle mask whose
4121 element type is always 'i32'. The result of the instruction is a vector
4122 whose length is the same as the shuffle mask and whose element type is the
4123 same as the element type of the first two operands.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4124
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4125<p>The shuffle mask operand is required to be a constant vector with either
4126 constant integer or undef values.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4127
4128<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4129<p>The elements of the two input vectors are numbered from left to right across
4130 both of the vectors. The shuffle mask operand specifies, for each element of
4131 the result vector, which element of the two input vectors the result element
4132 gets. The element selector may be undef (meaning "don't care") and the
4133 second operand may be undef if performing a shuffle from only one vector.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4134
4135<h5>Example:</h5>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4136<pre>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4137 &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]4138 &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]4139 &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]4140 &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]4141 &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]4142 &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]4143 &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]4144 &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]4145</pre>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4146
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4147</div>
Tanya Lattnerb138bbe2006-04-14 19:24:33 +0000[diff] [blame]4148
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4149<!-- ======================================================================= -->
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4150<div class="doc_subsection">
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4151 <a name="aggregateops">Aggregate Operations</a>
4152</div>
4153
4154<div class="doc_text">
4155
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]4156<p>LLVM supports several instructions for working with
4157 <a href="#t_aggregate">aggregate</a> values.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4158
4159</div>
4160
4161<!-- _______________________________________________________________________ -->
4162<div class="doc_subsubsection">
4163 <a name="i_extractvalue">'<tt>extractvalue</tt>' Instruction</a>
4164</div>
4165
4166<div class="doc_text">
4167
4168<h5>Syntax:</h5>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4169<pre>
4170 &lt;result&gt; = extractvalue &lt;aggregate type&gt; &lt;val&gt;, &lt;idx&gt;{, &lt;idx&gt;}*
4171</pre>
4172
4173<h5>Overview:</h5>
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]4174<p>The '<tt>extractvalue</tt>' instruction extracts the value of a member field
4175 from an <a href="#t_aggregate">aggregate</a> value.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4176
4177<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4178<p>The first operand of an '<tt>extractvalue</tt>' instruction is a value
Chris Lattner13ee7952010-08-28 04:09:24 +0000[diff] [blame]4179 of <a href="#t_struct">struct</a> or
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]4180 <a href="#t_array">array</a> type. The operands are constant indices to
4181 specify which value to extract in a similar manner as indices in a
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4182 '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
Frits van Bommel7cf63ac2010-12-05 20:54:38 +0000[diff] [blame]4183 <p>The major differences to <tt>getelementptr</tt> indexing are:</p>
4184 <ul>
4185 <li>Since the value being indexed is not a pointer, the first index is
4186 omitted and assumed to be zero.</li>
4187 <li>At least one index must be specified.</li>
4188 <li>Not only struct indices but also array indices must be in
4189 bounds.</li>
4190 </ul>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4191
4192<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4193<p>The result is the value at the position in the aggregate specified by the
4194 index operands.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4195
4196<h5>Example:</h5>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4197<pre>
Gabor Greif03ab4dc2009-10-28 13:14:50 +0000[diff] [blame]4198 &lt;result&gt; = extractvalue {i32, float} %agg, 0 <i>; yields i32</i>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4199</pre>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4200
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4201</div>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4202
4203<!-- _______________________________________________________________________ -->
4204<div class="doc_subsubsection">
4205 <a name="i_insertvalue">'<tt>insertvalue</tt>' Instruction</a>
4206</div>
4207
4208<div class="doc_text">
4209
4210<h5>Syntax:</h5>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4211<pre>
Jeffrey Yasskinf991bbb2010-01-11 19:19:26 +0000[diff] [blame]4212 &lt;result&gt; = insertvalue &lt;aggregate type&gt; &lt;val&gt;, &lt;ty&gt; &lt;elt&gt;, &lt;idx&gt; <i>; yields &lt;aggregate type&gt;</i>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4213</pre>
4214
4215<h5>Overview:</h5>
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]4216<p>The '<tt>insertvalue</tt>' instruction inserts a value into a member field
4217 in an <a href="#t_aggregate">aggregate</a> value.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4218
4219<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4220<p>The first operand of an '<tt>insertvalue</tt>' instruction is a value
Chris Lattner13ee7952010-08-28 04:09:24 +0000[diff] [blame]4221 of <a href="#t_struct">struct</a> or
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]4222 <a href="#t_array">array</a> type. The second operand is a first-class
4223 value to insert. The following operands are constant indices indicating
4224 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]4225 '<tt><a href="#i_extractvalue">extractvalue</a></tt>' instruction. The
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4226 value to insert must have the same type as the value identified by the
4227 indices.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4228
4229<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4230<p>The result is an aggregate of the same type as <tt>val</tt>. Its value is
4231 that of <tt>val</tt> except that the value at the position specified by the
4232 indices is that of <tt>elt</tt>.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4233
4234<h5>Example:</h5>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4235<pre>
Jeffrey Yasskinf991bbb2010-01-11 19:19:26 +0000[diff] [blame]4236 %agg1 = insertvalue {i32, float} undef, i32 1, 0 <i>; yields {i32 1, float undef}</i>
4237 %agg2 = insertvalue {i32, float} %agg1, float %val, 1 <i>; yields {i32 1, float %val}</i>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4238</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4239
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4240</div>
4241
4242
4243<!-- ======================================================================= -->
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4244<div class="doc_subsection">
Chris Lattner6ab66722006-08-15 00:45:58 +0000[diff] [blame]4245 <a name="memoryops">Memory Access and Addressing Operations</a>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4246</div>
4247
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4248<div class="doc_text">
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4249
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4250<p>A key design point of an SSA-based representation is how it represents
4251 memory. In LLVM, no memory locations are in SSA form, which makes things
Victor Hernandeza70c6df2009-10-26 23:44:29 +0000[diff] [blame]4252 very simple. This section describes how to read, write, and allocate
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4253 memory in LLVM.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4254
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4255</div>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4256
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4257<!-- _______________________________________________________________________ -->
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4258<div class="doc_subsubsection">
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4259 <a name="i_alloca">'<tt>alloca</tt>' Instruction</a>
4260</div>
4261
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4262<div class="doc_text">
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4263
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4264<h5>Syntax:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4265<pre>
Dan Gohman2140a742010-05-28 01:14:11 +0000[diff] [blame]4266 &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]4267</pre>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4268
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4269<h5>Overview:</h5>
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]4270<p>The '<tt>alloca</tt>' instruction allocates memory on the stack frame of the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4271 currently executing function, to be automatically released when this function
4272 returns to its caller. The object is always allocated in the generic address
4273 space (address space zero).</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4274
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4275<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4276<p>The '<tt>alloca</tt>' instruction
4277 allocates <tt>sizeof(&lt;type&gt;)*NumElements</tt> bytes of memory on the
4278 runtime stack, returning a pointer of the appropriate type to the program.
4279 If "NumElements" is specified, it is the number of elements allocated,
4280 otherwise "NumElements" is defaulted to be one. If a constant alignment is
4281 specified, the value result of the allocation is guaranteed to be aligned to
4282 at least that boundary. If not specified, or if zero, the target can choose
4283 to align the allocation on any convenient boundary compatible with the
4284 type.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4285
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4286<p>'<tt>type</tt>' may be any sized type.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4287
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4288<h5>Semantics:</h5>
Bill Wendling9ee6a312009-05-08 20:49:29 +0000[diff] [blame]4289<p>Memory is allocated; a pointer is returned. The operation is undefined if
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4290 there is insufficient stack space for the allocation. '<tt>alloca</tt>'d
4291 memory is automatically released when the function returns. The
4292 '<tt>alloca</tt>' instruction is commonly used to represent automatic
4293 variables that must have an address available. When the function returns
4294 (either with the <tt><a href="#i_ret">ret</a></tt>
4295 or <tt><a href="#i_unwind">unwind</a></tt> instructions), the memory is
4296 reclaimed. Allocating zero bytes is legal, but the result is undefined.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4297
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4298<h5>Example:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4299<pre>
Dan Gohman7a5acb52009-01-04 23:49:44 +0000[diff] [blame]4300 %ptr = alloca i32 <i>; yields {i32*}:ptr</i>
4301 %ptr = alloca i32, i32 4 <i>; yields {i32*}:ptr</i>
4302 %ptr = alloca i32, i32 4, align 1024 <i>; yields {i32*}:ptr</i>
4303 %ptr = alloca i32, align 1024 <i>; yields {i32*}:ptr</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4304</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4305
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4306</div>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4307
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4308<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]4309<div class="doc_subsubsection"> <a name="i_load">'<tt>load</tt>'
4310Instruction</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4311
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4312<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4313
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4314<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4315<pre>
Bill Wendlingbc4024f2010-02-25 21:23:24 +0000[diff] [blame]4316 &lt;result&gt; = load &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;][, !nontemporal !&lt;index&gt;]
4317 &lt;result&gt; = volatile load &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;][, !nontemporal !&lt;index&gt;]
4318 !&lt;index&gt; = !{ i32 1 }
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4319</pre>
4320
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4321<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4322<p>The '<tt>load</tt>' instruction is used to read from memory.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4323
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4324<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4325<p>The argument to the '<tt>load</tt>' instruction specifies the memory address
4326 from which to load. The pointer must point to
4327 a <a href="#t_firstclass">first class</a> type. If the <tt>load</tt> is
4328 marked as <tt>volatile</tt>, then the optimizer is not allowed to modify the
Jeffrey Yasskin5d284ae2010-04-26 21:21:24 +0000[diff] [blame]4329 number or order of execution of this <tt>load</tt> with other <a
4330 href="#volatile">volatile operations</a>.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4331
Bill Wendlingbc4024f2010-02-25 21:23:24 +0000[diff] [blame]4332<p>The optional constant <tt>align</tt> argument specifies the alignment of the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4333 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]4334 omitted <tt>align</tt> argument means that the operation has the preferential
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4335 alignment for the target. It is the responsibility of the code emitter to
4336 ensure that the alignment information is correct. Overestimating the
Bill Wendlingbc4024f2010-02-25 21:23:24 +0000[diff] [blame]4337 alignment results in undefined behavior. Underestimating the alignment may
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4338 produce less efficient code. An alignment of 1 is always safe.</p>
4339
Bill Wendlingbc4024f2010-02-25 21:23:24 +0000[diff] [blame]4340<p>The optional <tt>!nontemporal</tt> metadata must reference a single
4341 metatadata name &lt;index&gt; corresponding to a metadata node with
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]4342 one <tt>i32</tt> entry of value 1. The existence of
Bill Wendlingbc4024f2010-02-25 21:23:24 +0000[diff] [blame]4343 the <tt>!nontemporal</tt> metatadata on the instruction tells the optimizer
4344 and code generator that this load is not expected to be reused in the cache.
4345 The code generator may select special instructions to save cache bandwidth,
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]4346 such as the <tt>MOVNT</tt> instruction on x86.</p>
David Greene9641d062010-02-16 20:50:18 +0000[diff] [blame]4347
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4348<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4349<p>The location of memory pointed to is loaded. If the value being loaded is of
4350 scalar type then the number of bytes read does not exceed the minimum number
4351 of bytes needed to hold all bits of the type. For example, loading an
4352 <tt>i24</tt> reads at most three bytes. When loading a value of a type like
4353 <tt>i20</tt> with a size that is not an integral number of bytes, the result
4354 is undefined if the value was not originally written using a store of the
4355 same type.</p>
4356
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4357<h5>Examples:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4358<pre>
4359 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
4360 <a href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4361 %val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4362</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4363
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4364</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4365
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4366<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]4367<div class="doc_subsubsection"> <a name="i_store">'<tt>store</tt>'
4368Instruction</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4369
Reid Spencera89fb182006-11-09 21:18:01 +0000[diff] [blame]4370<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4371
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4372<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4373<pre>
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]4374 store &lt;ty&gt; &lt;value&gt;, &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;][, !nontemporal !&lt;index&gt;] <i>; yields {void}</i>
4375 volatile store &lt;ty&gt; &lt;value&gt;, &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;][, !nontemporal !&lt;index&gt;] <i>; yields {void}</i>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4376</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4377
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4378<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4379<p>The '<tt>store</tt>' instruction is used to write to memory.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4380
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4381<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4382<p>There are two arguments to the '<tt>store</tt>' instruction: a value to store
4383 and an address at which to store it. The type of the
4384 '<tt>&lt;pointer&gt;</tt>' operand must be a pointer to
4385 the <a href="#t_firstclass">first class</a> type of the
Jeffrey Yasskin5d284ae2010-04-26 21:21:24 +0000[diff] [blame]4386 '<tt>&lt;value&gt;</tt>' operand. If the <tt>store</tt> is marked as
4387 <tt>volatile</tt>, then the optimizer is not allowed to modify the number or
4388 order of execution of this <tt>store</tt> with other <a
4389 href="#volatile">volatile operations</a>.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4390
4391<p>The optional constant "align" argument specifies the alignment of the
4392 operation (that is, the alignment of the memory address). A value of 0 or an
4393 omitted "align" argument means that the operation has the preferential
4394 alignment for the target. It is the responsibility of the code emitter to
4395 ensure that the alignment information is correct. Overestimating the
4396 alignment results in an undefined behavior. Underestimating the alignment may
4397 produce less efficient code. An alignment of 1 is always safe.</p>
4398
David Greene9641d062010-02-16 20:50:18 +0000[diff] [blame]4399<p>The optional !nontemporal metadata must reference a single metatadata
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]4400 name &lt;index&gt; corresponding to a metadata node with one i32 entry of
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]4401 value 1. The existence of the !nontemporal metatadata on the
David Greene9641d062010-02-16 20:50:18 +0000[diff] [blame]4402 instruction tells the optimizer and code generator that this load is
4403 not expected to be reused in the cache. The code generator may
4404 select special instructions to save cache bandwidth, such as the
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]4405 MOVNT instruction on x86.</p>
David Greene9641d062010-02-16 20:50:18 +0000[diff] [blame]4406
4407
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]4408<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4409<p>The contents of memory are updated to contain '<tt>&lt;value&gt;</tt>' at the
4410 location specified by the '<tt>&lt;pointer&gt;</tt>' operand. If
4411 '<tt>&lt;value&gt;</tt>' is of scalar type then the number of bytes written
4412 does not exceed the minimum number of bytes needed to hold all bits of the
4413 type. For example, storing an <tt>i24</tt> writes at most three bytes. When
4414 writing a value of a type like <tt>i20</tt> with a size that is not an
4415 integral number of bytes, it is unspecified what happens to the extra bits
4416 that do not belong to the type, but they will typically be overwritten.</p>
4417
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4418<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4419<pre>
4420 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Bill Wendling8830ffe2007-10-22 05:10:05 +0000[diff] [blame]4421 store i32 3, i32* %ptr <i>; yields {void}</i>
4422 %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]4423</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4424
Reid Spencer443460a2006-11-09 21:15:49 +0000[diff] [blame]4425</div>
4426
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4427<!-- _______________________________________________________________________ -->
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4428<div class="doc_subsubsection">
4429 <a name="i_getelementptr">'<tt>getelementptr</tt>' Instruction</a>
4430</div>
4431
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4432<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4433
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]4434<h5>Syntax:</h5>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4435<pre>
Matthijs Kooijman0e268272008-10-13 13:44:15 +0000[diff] [blame]4436 &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]4437 &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]4438</pre>
4439
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]4440<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4441<p>The '<tt>getelementptr</tt>' instruction is used to get the address of a
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]4442 subelement of an <a href="#t_aggregate">aggregate</a> data structure.
4443 It performs address calculation only and does not access memory.</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4444
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]4445<h5>Arguments:</h5>
Matthijs Kooijman0e268272008-10-13 13:44:15 +0000[diff] [blame]4446<p>The first argument is always a pointer, and forms the basis of the
Chris Lattnera40b9122009-07-29 06:44:13 +0000[diff] [blame]4447 calculation. The remaining arguments are indices that indicate which of the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4448 elements of the aggregate object are indexed. The interpretation of each
4449 index is dependent on the type being indexed into. The first index always
4450 indexes the pointer value given as the first argument, the second index
4451 indexes a value of the type pointed to (not necessarily the value directly
4452 pointed to, since the first index can be non-zero), etc. The first type
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]4453 indexed into must be a pointer value, subsequent types can be arrays,
Chris Lattner13ee7952010-08-28 04:09:24 +0000[diff] [blame]4454 vectors, and structs. Note that subsequent types being indexed into
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]4455 can never be pointers, since that would require loading the pointer before
4456 continuing calculation.</p>
Matthijs Kooijman0e268272008-10-13 13:44:15 +0000[diff] [blame]4457
4458<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]4459 When indexing into a (optionally packed) structure, only <tt>i32</tt>
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]4460 integer <b>constants</b> are allowed. When indexing into an array, pointer
4461 or vector, integers of any width are allowed, and they are not required to be
Chris Lattnera40b9122009-07-29 06:44:13 +0000[diff] [blame]4462 constant.</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4463
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4464<p>For example, let's consider a C code fragment and how it gets compiled to
4465 LLVM:</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4466
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]4467<pre class="doc_code">
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]4468struct RT {
4469 char A;
Chris Lattnera446f1b2007-05-29 15:43:56 +0000[diff] [blame]4470 int B[10][20];
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]4471 char C;
4472};
4473struct ST {
Chris Lattnera446f1b2007-05-29 15:43:56 +0000[diff] [blame]4474 int X;
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]4475 double Y;
4476 struct RT Z;
4477};
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4478
Chris Lattnera446f1b2007-05-29 15:43:56 +0000[diff] [blame]4479int *foo(struct ST *s) {
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]4480 return &amp;s[1].Z.B[5][13];
4481}
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4482</pre>
4483
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4484<p>The LLVM code generated by the GCC frontend is:</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4485
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]4486<pre class="doc_code">
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]4487%RT = <a href="#namedtypes">type</a> { i8 , [10 x [20 x i32]], i8 }
4488%ST = <a href="#namedtypes">type</a> { i32, double, %RT }
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4489
Dan Gohman6b867702009-07-25 02:23:48 +0000[diff] [blame]4490define i32* @foo(%ST* %s) {
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]4491entry:
4492 %reg = getelementptr %ST* %s, i32 1, i32 2, i32 1, i32 5, i32 13
4493 ret i32* %reg
4494}
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4495</pre>
4496
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]4497<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4498<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]4499 type, which is a pointer, yielding a '<tt>%ST</tt>' = '<tt>{ i32, double, %RT
4500 }</tt>' type, a structure. The second index indexes into the third element
4501 of the structure, yielding a '<tt>%RT</tt>' = '<tt>{ i8 , [10 x [20 x i32]],
4502 i8 }</tt>' type, another structure. The third index indexes into the second
4503 element of the structure, yielding a '<tt>[10 x [20 x i32]]</tt>' type, an
4504 array. The two dimensions of the array are subscripted into, yielding an
4505 '<tt>i32</tt>' type. The '<tt>getelementptr</tt>' instruction returns a
4506 pointer to this element, thus computing a value of '<tt>i32*</tt>' type.</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4507
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4508<p>Note that it is perfectly legal to index partially through a structure,
4509 returning a pointer to an inner element. Because of this, the LLVM code for
4510 the given testcase is equivalent to:</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4511
4512<pre>
Dan Gohman6b867702009-07-25 02:23:48 +0000[diff] [blame]4513 define i32* @foo(%ST* %s) {
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4514 %t1 = getelementptr %ST* %s, i32 1 <i>; yields %ST*:%t1</i>
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]4515 %t2 = getelementptr %ST* %t1, i32 0, i32 2 <i>; yields %RT*:%t2</i>
4516 %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]4517 %t4 = getelementptr [10 x [20 x i32]]* %t3, i32 0, i32 5 <i>; yields [20 x i32]*:%t4</i>
4518 %t5 = getelementptr [20 x i32]* %t4, i32 0, i32 13 <i>; yields i32*:%t5</i>
4519 ret i32* %t5
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4520 }
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]4521</pre>
Chris Lattnerc0ad71e2005-06-24 17:22:57 +0000[diff] [blame]4522
Dan Gohman1639c392009-07-27 21:53:46 +0000[diff] [blame]4523<p>If the <tt>inbounds</tt> keyword is present, the result value of the
Dan Gohman57255802010-04-23 15:23:32 +0000[diff] [blame]4524 <tt>getelementptr</tt> is a <a href="#trapvalues">trap value</a> if the
4525 base pointer is not an <i>in bounds</i> address of an allocated object,
4526 or if any of the addresses that would be formed by successive addition of
4527 the offsets implied by the indices to the base address with infinitely
4528 precise arithmetic are not an <i>in bounds</i> address of that allocated
4529 object. The <i>in bounds</i> addresses for an allocated object are all
4530 the addresses that point into the object, plus the address one byte past
4531 the end.</p>
Dan Gohman1639c392009-07-27 21:53:46 +0000[diff] [blame]4532
4533<p>If the <tt>inbounds</tt> keyword is not present, the offsets are added to
4534 the base address with silently-wrapping two's complement arithmetic, and
4535 the result value of the <tt>getelementptr</tt> may be outside the object
4536 pointed to by the base pointer. The result value may not necessarily be
4537 used to access memory though, even if it happens to point into allocated
4538 storage. See the <a href="#pointeraliasing">Pointer Aliasing Rules</a>
4539 section for more information.</p>
4540
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4541<p>The getelementptr instruction is often confusing. For some more insight into
4542 how it works, see <a href="GetElementPtr.html">the getelementptr FAQ</a>.</p>
Chris Lattner6ab66722006-08-15 00:45:58 +0000[diff] [blame]4543
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]4544<h5>Example:</h5>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4545<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4546 <i>; yields [12 x i8]*:aptr</i>
Matthijs Kooijman0e268272008-10-13 13:44:15 +0000[diff] [blame]4547 %aptr = getelementptr {i32, [12 x i8]}* %saptr, i64 0, i32 1
4548 <i>; yields i8*:vptr</i>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]4549 %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]4550 <i>; yields i8*:eptr</i>
4551 %eptr = getelementptr [12 x i8]* %aptr, i64 0, i32 1
Sanjiv Gupta0c155e62009-04-25 07:27:44 +0000[diff] [blame]4552 <i>; yields i32*:iptr</i>
Sanjiv Gupta77abea02009-04-24 16:38:13 +0000[diff] [blame]4553 %iptr = getelementptr [10 x i32]* @arr, i16 0, i16 0
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4554</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4555
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4556</div>
Reid Spencer443460a2006-11-09 21:15:49 +0000[diff] [blame]4557
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4558<!-- ======================================================================= -->
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]4559<div class="doc_subsection"> <a name="convertops">Conversion Operations</a>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4560</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4561
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4562<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4563
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]4564<p>The instructions in this category are the conversion instructions (casting)
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4565 which all take a single operand and a type. They perform various bit
4566 conversions on the operand.</p>
4567
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4568</div>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]4569
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]4570<!-- _______________________________________________________________________ -->
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]4571<div class="doc_subsubsection">
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4572 <a name="i_trunc">'<tt>trunc .. to</tt>' Instruction</a>
4573</div>
4574<div class="doc_text">
4575
4576<h5>Syntax:</h5>
4577<pre>
4578 &lt;result&gt; = trunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4579</pre>
4580
4581<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4582<p>The '<tt>trunc</tt>' instruction truncates its operand to the
4583 type <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4584
4585<h5>Arguments:</h5>
Nadav Rotem502f1b92011-02-24 21:01:34 +0000[diff] [blame]4586<p>The '<tt>trunc</tt>' instruction takes a value to trunc, and a type to trunc it to.
4587 Both types must be of <a href="#t_integer">integer</a> types, or vectors
4588 of the same number of integers.
4589 The bit size of the <tt>value</tt> must be larger than
4590 the bit size of the destination type, <tt>ty2</tt>.
4591 Equal sized types are not allowed.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4592
4593<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4594<p>The '<tt>trunc</tt>' instruction truncates the high order bits
4595 in <tt>value</tt> and converts the remaining bits to <tt>ty2</tt>. Since the
4596 source size must be larger than the destination size, <tt>trunc</tt> cannot
4597 be a <i>no-op cast</i>. It will always truncate bits.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4598
4599<h5>Example:</h5>
4600<pre>
Nadav Rotem502f1b92011-02-24 21:01:34 +0000[diff] [blame]4601 %X = trunc i32 257 to i8 <i>; yields i8:1</i>
4602 %Y = trunc i32 123 to i1 <i>; yields i1:true</i>
4603 %Z = trunc i32 122 to i1 <i>; yields i1:false</i>
4604 %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]4605</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4606
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4607</div>
4608
4609<!-- _______________________________________________________________________ -->
4610<div class="doc_subsubsection">
4611 <a name="i_zext">'<tt>zext .. to</tt>' Instruction</a>
4612</div>
4613<div class="doc_text">
4614
4615<h5>Syntax:</h5>
4616<pre>
4617 &lt;result&gt; = zext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4618</pre>
4619
4620<h5>Overview:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4621<p>The '<tt>zext</tt>' instruction zero extends its operand to type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4622 <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4623
4624
4625<h5>Arguments:</h5>
Nadav Rotem25f2ac92011-02-20 12:37:50 +0000[diff] [blame]4626<p>The '<tt>zext</tt>' instruction takes a value to cast, and a type to cast it to.
4627 Both types must be of <a href="#t_integer">integer</a> types, or vectors
4628 of the same number of integers.
4629 The bit size of the <tt>value</tt> must be smaller than
4630 the bit size of the destination type,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4631 <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4632
4633<h5>Semantics:</h5>
4634<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]4635 bits until it reaches the size of the destination type, <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4636
Reid Spencer07c9c682007-01-12 15:46:11 +0000[diff] [blame]4637<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]4638
4639<h5>Example:</h5>
4640<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4641 %X = zext i32 257 to i64 <i>; yields i64:257</i>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]4642 %Y = zext i1 true to i32 <i>; yields i32:1</i>
Nadav Rotem25f2ac92011-02-20 12:37:50 +0000[diff] [blame]4643 %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]4644</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4645
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4646</div>
4647
4648<!-- _______________________________________________________________________ -->
4649<div class="doc_subsubsection">
4650 <a name="i_sext">'<tt>sext .. to</tt>' Instruction</a>
4651</div>
4652<div class="doc_text">
4653
4654<h5>Syntax:</h5>
4655<pre>
4656 &lt;result&gt; = sext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4657</pre>
4658
4659<h5>Overview:</h5>
4660<p>The '<tt>sext</tt>' sign extends <tt>value</tt> to the type <tt>ty2</tt>.</p>
4661
4662<h5>Arguments:</h5>
Nadav Rotem502f1b92011-02-24 21:01:34 +0000[diff] [blame]4663<p>The '<tt>sext</tt>' instruction takes a value to cast, and a type to cast it to.
4664 Both types must be of <a href="#t_integer">integer</a> types, or vectors
4665 of the same number of integers.
4666 The bit size of the <tt>value</tt> must be smaller than
4667 the bit size of the destination type,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4668 <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4669
4670<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4671<p>The '<tt>sext</tt>' instruction performs a sign extension by copying the sign
4672 bit (highest order bit) of the <tt>value</tt> until it reaches the bit size
4673 of the type <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4674
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]4675<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]4676
4677<h5>Example:</h5>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4678<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4679 %X = sext i8 -1 to i16 <i>; yields i16 :65535</i>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]4680 %Y = sext i1 true to i32 <i>; yields i32:-1</i>
Nadav Rotem502f1b92011-02-24 21:01:34 +0000[diff] [blame]4681 %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]4682</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4683
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4684</div>
4685
4686<!-- _______________________________________________________________________ -->
4687<div class="doc_subsubsection">
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]4688 <a name="i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a>
4689</div>
4690
4691<div class="doc_text">
4692
4693<h5>Syntax:</h5>
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]4694<pre>
4695 &lt;result&gt; = fptrunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4696</pre>
4697
4698<h5>Overview:</h5>
4699<p>The '<tt>fptrunc</tt>' instruction truncates <tt>value</tt> to type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4700 <tt>ty2</tt>.</p>
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]4701
4702<h5>Arguments:</h5>
4703<p>The '<tt>fptrunc</tt>' instruction takes a <a href="#t_floating">floating
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4704 point</a> value to cast and a <a href="#t_floating">floating point</a> type
4705 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]4706 <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]4707 <i>no-op cast</i>.</p>
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]4708
4709<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4710<p>The '<tt>fptrunc</tt>' instruction truncates a <tt>value</tt> from a larger
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4711 <a href="#t_floating">floating point</a> type to a smaller
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4712 <a href="#t_floating">floating point</a> type. If the value cannot fit
4713 within the destination type, <tt>ty2</tt>, then the results are
4714 undefined.</p>
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]4715
4716<h5>Example:</h5>
4717<pre>
4718 %X = fptrunc double 123.0 to float <i>; yields float:123.0</i>
4719 %Y = fptrunc double 1.0E+300 to float <i>; yields undefined</i>
4720</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4721
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]4722</div>
4723
4724<!-- _______________________________________________________________________ -->
4725<div class="doc_subsubsection">
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4726 <a name="i_fpext">'<tt>fpext .. to</tt>' Instruction</a>
4727</div>
4728<div class="doc_text">
4729
4730<h5>Syntax:</h5>
4731<pre>
4732 &lt;result&gt; = fpext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4733</pre>
4734
4735<h5>Overview:</h5>
4736<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]4737 floating point value.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4738
4739<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4740<p>The '<tt>fpext</tt>' instruction takes a
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4741 <a href="#t_floating">floating point</a> <tt>value</tt> to cast, and
4742 a <a href="#t_floating">floating point</a> type to cast it to. The source
4743 type must be smaller than the destination type.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4744
4745<h5>Semantics:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]4746<p>The '<tt>fpext</tt>' instruction extends the <tt>value</tt> from a smaller
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4747 <a href="#t_floating">floating point</a> type to a larger
4748 <a href="#t_floating">floating point</a> type. The <tt>fpext</tt> cannot be
4749 used to make a <i>no-op cast</i> because it always changes bits. Use
4750 <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]4751
4752<h5>Example:</h5>
4753<pre>
Nick Lewycky9feca672011-03-31 18:20:19 +0000[diff] [blame]4754 %X = fpext float 3.125 to double <i>; yields double:3.125000e+00</i>
4755 %Y = fpext double %X to fp128 <i>; yields fp128:0xL00000000000000004000900000000000</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4756</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4757
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4758</div>
4759
4760<!-- _______________________________________________________________________ -->
4761<div class="doc_subsubsection">
Reid Spencer2eadb532007-01-21 00:29:26 +0000[diff] [blame]4762 <a name="i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4763</div>
4764<div class="doc_text">
4765
4766<h5>Syntax:</h5>
4767<pre>
Reid Spencer753163d2007-07-31 14:40:14 +0000[diff] [blame]4768 &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]4769</pre>
4770
4771<h5>Overview:</h5>
Reid Spencer753163d2007-07-31 14:40:14 +0000[diff] [blame]4772<p>The '<tt>fptoui</tt>' converts a floating point <tt>value</tt> to its
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4773 unsigned integer equivalent of type <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4774
4775<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4776<p>The '<tt>fptoui</tt>' instruction takes a value to cast, which must be a
4777 scalar or vector <a href="#t_floating">floating point</a> value, and a type
4778 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
4779 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
4780 vector integer type with the same number of elements as <tt>ty</tt></p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4781
4782<h5>Semantics:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4783<p>The '<tt>fptoui</tt>' instruction converts its
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4784 <a href="#t_floating">floating point</a> operand into the nearest (rounding
4785 towards zero) unsigned integer value. If the value cannot fit
4786 in <tt>ty2</tt>, the results are undefined.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4787
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4788<h5>Example:</h5>
4789<pre>
Reid Spencer753163d2007-07-31 14:40:14 +0000[diff] [blame]4790 %X = fptoui double 123.0 to i32 <i>; yields i32:123</i>
Chris Lattner5b95a172007-09-22 03:17:52 +0000[diff] [blame]4791 %Y = fptoui float 1.0E+300 to i1 <i>; yields undefined:1</i>
Gabor Greiff50fd572009-10-28 09:21:30 +0000[diff] [blame]4792 %Z = fptoui float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4793</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4794
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4795</div>
4796
4797<!-- _______________________________________________________________________ -->
4798<div class="doc_subsubsection">
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]4799 <a name="i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4800</div>
4801<div class="doc_text">
4802
4803<h5>Syntax:</h5>
4804<pre>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]4805 &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]4806</pre>
4807
4808<h5>Overview:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4809<p>The '<tt>fptosi</tt>' instruction converts
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4810 <a href="#t_floating">floating point</a> <tt>value</tt> to
4811 type <tt>ty2</tt>.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]4812
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]4813<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4814<p>The '<tt>fptosi</tt>' instruction takes a value to cast, which must be a
4815 scalar or vector <a href="#t_floating">floating point</a> value, and a type
4816 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
4817 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
4818 vector integer type with the same number of elements as <tt>ty</tt></p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]4819
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]4820<h5>Semantics:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4821<p>The '<tt>fptosi</tt>' instruction converts its
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4822 <a href="#t_floating">floating point</a> operand into the nearest (rounding
4823 towards zero) signed integer value. If the value cannot fit in <tt>ty2</tt>,
4824 the results are undefined.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]4825
Chris Lattner70de6632001-07-09 00:26:23 +0000[diff] [blame]4826<h5>Example:</h5>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]4827<pre>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]4828 %X = fptosi double -123.0 to i32 <i>; yields i32:-123</i>
Chris Lattner5b95a172007-09-22 03:17:52 +0000[diff] [blame]4829 %Y = fptosi float 1.0E-247 to i1 <i>; yields undefined:1</i>
Gabor Greiff50fd572009-10-28 09:21:30 +0000[diff] [blame]4830 %Z = fptosi float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4831</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4832
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4833</div>
4834
4835<!-- _______________________________________________________________________ -->
4836<div class="doc_subsubsection">
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]4837 <a name="i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4838</div>
4839<div class="doc_text">
4840
4841<h5>Syntax:</h5>
4842<pre>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]4843 &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]4844</pre>
4845
4846<h5>Overview:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]4847<p>The '<tt>uitofp</tt>' instruction regards <tt>value</tt> as an unsigned
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4848 integer and converts that value to the <tt>ty2</tt> type.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4849
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4850<h5>Arguments:</h5>
Nate Begemand4d45c22007-11-17 03:58:34 +0000[diff] [blame]4851<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]4852 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
4853 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
4854 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
4855 floating point type with the same number of elements as <tt>ty</tt></p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4856
4857<h5>Semantics:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]4858<p>The '<tt>uitofp</tt>' instruction interprets its operand as an unsigned
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4859 integer quantity and converts it to the corresponding floating point
4860 value. If the value cannot fit in the floating point value, the results are
4861 undefined.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4862
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4863<h5>Example:</h5>
4864<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4865 %X = uitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]4866 %Y = uitofp i8 -1 to double <i>; yields double:255.0</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4867</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4868
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4869</div>
4870
4871<!-- _______________________________________________________________________ -->
4872<div class="doc_subsubsection">
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]4873 <a name="i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4874</div>
4875<div class="doc_text">
4876
4877<h5>Syntax:</h5>
4878<pre>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]4879 &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]4880</pre>
4881
4882<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4883<p>The '<tt>sitofp</tt>' instruction regards <tt>value</tt> as a signed integer
4884 and converts that value to the <tt>ty2</tt> type.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4885
4886<h5>Arguments:</h5>
Nate Begemand4d45c22007-11-17 03:58:34 +0000[diff] [blame]4887<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]4888 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
4889 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
4890 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
4891 floating point type with the same number of elements as <tt>ty</tt></p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4892
4893<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4894<p>The '<tt>sitofp</tt>' instruction interprets its operand as a signed integer
4895 quantity and converts it to the corresponding floating point value. If the
4896 value cannot fit in the floating point value, the results are undefined.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4897
4898<h5>Example:</h5>
4899<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4900 %X = sitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]4901 %Y = sitofp i8 -1 to double <i>; yields double:-1.0</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4902</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4903
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4904</div>
4905
4906<!-- _______________________________________________________________________ -->
4907<div class="doc_subsubsection">
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]4908 <a name="i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a>
4909</div>
4910<div class="doc_text">
4911
4912<h5>Syntax:</h5>
4913<pre>
4914 &lt;result&gt; = ptrtoint &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4915</pre>
4916
4917<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4918<p>The '<tt>ptrtoint</tt>' instruction converts the pointer <tt>value</tt> to
4919 the integer type <tt>ty2</tt>.</p>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]4920
4921<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4922<p>The '<tt>ptrtoint</tt>' instruction takes a <tt>value</tt> to cast, which
4923 must be a <a href="#t_pointer">pointer</a> value, and a type to cast it to
4924 <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]4925
4926<h5>Semantics:</h5>
4927<p>The '<tt>ptrtoint</tt>' instruction converts <tt>value</tt> to integer type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4928 <tt>ty2</tt> by interpreting the pointer value as an integer and either
4929 truncating or zero extending that value to the size of the integer type. If
4930 <tt>value</tt> is smaller than <tt>ty2</tt> then a zero extension is done. If
4931 <tt>value</tt> is larger than <tt>ty2</tt> then a truncation is done. If they
4932 are the same size, then nothing is done (<i>no-op cast</i>) other than a type
4933 change.</p>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]4934
4935<h5>Example:</h5>
4936<pre>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]4937 %X = ptrtoint i32* %X to i8 <i>; yields truncation on 32-bit architecture</i>
4938 %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]4939</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4940
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]4941</div>
4942
4943<!-- _______________________________________________________________________ -->
4944<div class="doc_subsubsection">
4945 <a name="i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a>
4946</div>
4947<div class="doc_text">
4948
4949<h5>Syntax:</h5>
4950<pre>
4951 &lt;result&gt; = inttoptr &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4952</pre>
4953
4954<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4955<p>The '<tt>inttoptr</tt>' instruction converts an integer <tt>value</tt> to a
4956 pointer type, <tt>ty2</tt>.</p>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]4957
4958<h5>Arguments:</h5>
Duncan Sands16f122e2007-03-30 12:22:09 +0000[diff] [blame]4959<p>The '<tt>inttoptr</tt>' instruction takes an <a href="#t_integer">integer</a>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4960 value to cast, and a type to cast it to, which must be a
4961 <a href="#t_pointer">pointer</a> type.</p>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]4962
4963<h5>Semantics:</h5>
4964<p>The '<tt>inttoptr</tt>' instruction converts <tt>value</tt> to type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4965 <tt>ty2</tt> by applying either a zero extension or a truncation depending on
4966 the size of the integer <tt>value</tt>. If <tt>value</tt> is larger than the
4967 size of a pointer then a truncation is done. If <tt>value</tt> is smaller
4968 than the size of a pointer then a zero extension is done. If they are the
4969 same size, nothing is done (<i>no-op cast</i>).</p>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]4970
4971<h5>Example:</h5>
4972<pre>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]4973 %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]4974 %Y = inttoptr i32 255 to i32* <i>; yields no-op on 32-bit architecture</i>
4975 %Z = inttoptr i64 0 to i32* <i>; yields truncation on 32-bit architecture</i>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]4976</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4977
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]4978</div>
4979
4980<!-- _______________________________________________________________________ -->
4981<div class="doc_subsubsection">
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]4982 <a name="i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4983</div>
4984<div class="doc_text">
4985
4986<h5>Syntax:</h5>
4987<pre>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]4988 &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]4989</pre>
4990
4991<h5>Overview:</h5>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]4992<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4993 <tt>ty2</tt> without changing any bits.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4994
4995<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4996<p>The '<tt>bitcast</tt>' instruction takes a value to cast, which must be a
4997 non-aggregate first class value, and a type to cast it to, which must also be
4998 a non-aggregate <a href="#t_firstclass">first class</a> type. The bit sizes
4999 of <tt>value</tt> and the destination type, <tt>ty2</tt>, must be
5000 identical. If the source type is a pointer, the destination type must also be
5001 a pointer. This instruction supports bitwise conversion of vectors to
5002 integers and to vectors of other types (as long as they have the same
5003 size).</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5004
5005<h5>Semantics:</h5>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]5006<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5007 <tt>ty2</tt>. It is always a <i>no-op cast</i> because no bits change with
5008 this conversion. The conversion is done as if the <tt>value</tt> had been
5009 stored to memory and read back as type <tt>ty2</tt>. Pointer types may only
5010 be converted to other pointer types with this instruction. To convert
5011 pointers to other types, use the <a href="#i_inttoptr">inttoptr</a> or
5012 <a href="#i_ptrtoint">ptrtoint</a> instructions first.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5013
5014<h5>Example:</h5>
5015<pre>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5016 %X = bitcast i8 255 to i8 <i>; yields i8 :-1</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]5017 %Y = bitcast i32* %x to sint* <i>; yields sint*:%x</i>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5018 %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]5019</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5020
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5021</div>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5022
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5023<!-- ======================================================================= -->
5024<div class="doc_subsection"> <a name="otherops">Other Operations</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5025
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5026<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5027
5028<p>The instructions in this category are the "miscellaneous" instructions, which
5029 defy better classification.</p>
5030
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5031</div>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5032
5033<!-- _______________________________________________________________________ -->
5034<div class="doc_subsubsection"><a name="i_icmp">'<tt>icmp</tt>' Instruction</a>
5035</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5036
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5037<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5038
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5039<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5040<pre>
5041 &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]5042</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5043
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5044<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5045<p>The '<tt>icmp</tt>' instruction returns a boolean value or a vector of
5046 boolean values based on comparison of its two integer, integer vector, or
5047 pointer operands.</p>
5048
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5049<h5>Arguments:</h5>
5050<p>The '<tt>icmp</tt>' instruction takes three operands. The first operand is
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5051 the condition code indicating the kind of comparison to perform. It is not a
5052 value, just a keyword. The possible condition code are:</p>
5053
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5054<ol>
5055 <li><tt>eq</tt>: equal</li>
5056 <li><tt>ne</tt>: not equal </li>
5057 <li><tt>ugt</tt>: unsigned greater than</li>
5058 <li><tt>uge</tt>: unsigned greater or equal</li>
5059 <li><tt>ult</tt>: unsigned less than</li>
5060 <li><tt>ule</tt>: unsigned less or equal</li>
5061 <li><tt>sgt</tt>: signed greater than</li>
5062 <li><tt>sge</tt>: signed greater or equal</li>
5063 <li><tt>slt</tt>: signed less than</li>
5064 <li><tt>sle</tt>: signed less or equal</li>
5065</ol>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5066
Chris Lattnerc0f423a2007-01-15 01:54:13 +0000[diff] [blame]5067<p>The remaining two arguments must be <a href="#t_integer">integer</a> or
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5068 <a href="#t_pointer">pointer</a> or integer <a href="#t_vector">vector</a>
5069 typed. They must also be identical types.</p>
5070
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5071<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5072<p>The '<tt>icmp</tt>' compares <tt>op1</tt> and <tt>op2</tt> according to the
5073 condition code given as <tt>cond</tt>. The comparison performed always yields
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]5074 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]5075 result, as follows:</p>
5076
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5077<ol>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5078 <li><tt>eq</tt>: yields <tt>true</tt> if the operands are equal,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5079 <tt>false</tt> otherwise. No sign interpretation is necessary or
5080 performed.</li>
5081
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5082 <li><tt>ne</tt>: yields <tt>true</tt> if the operands are unequal,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5083 <tt>false</tt> otherwise. No sign interpretation is necessary or
5084 performed.</li>
5085
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5086 <li><tt>ugt</tt>: interprets the operands as unsigned values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5087 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
5088
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5089 <li><tt>uge</tt>: interprets the operands as unsigned values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5090 <tt>true</tt> if <tt>op1</tt> is greater than or equal
5091 to <tt>op2</tt>.</li>
5092
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5093 <li><tt>ult</tt>: interprets the operands as unsigned values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5094 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
5095
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5096 <li><tt>ule</tt>: interprets the operands as unsigned values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5097 <tt>true</tt> if <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
5098
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5099 <li><tt>sgt</tt>: interprets the operands as signed values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5100 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
5101
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5102 <li><tt>sge</tt>: interprets the operands as signed values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5103 <tt>true</tt> if <tt>op1</tt> is greater than or equal
5104 to <tt>op2</tt>.</li>
5105
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5106 <li><tt>slt</tt>: interprets the operands as signed values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5107 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
5108
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5109 <li><tt>sle</tt>: interprets the operands as signed values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5110 <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]5111</ol>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5112
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5113<p>If the operands are <a href="#t_pointer">pointer</a> typed, the pointer
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5114 values are compared as if they were integers.</p>
5115
5116<p>If the operands are integer vectors, then they are compared element by
5117 element. The result is an <tt>i1</tt> vector with the same number of elements
5118 as the values being compared. Otherwise, the result is an <tt>i1</tt>.</p>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5119
5120<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5121<pre>
5122 &lt;result&gt; = icmp eq i32 4, 5 <i>; yields: result=false</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]5123 &lt;result&gt; = icmp ne float* %X, %X <i>; yields: result=false</i>
5124 &lt;result&gt; = icmp ult i16 4, 5 <i>; yields: result=true</i>
5125 &lt;result&gt; = icmp sgt i16 4, 5 <i>; yields: result=false</i>
5126 &lt;result&gt; = icmp ule i16 -4, 5 <i>; yields: result=false</i>
5127 &lt;result&gt; = icmp sge i16 4, 5 <i>; yields: result=false</i>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5128</pre>
Dan Gohmana5127ab2009-01-22 01:39:38 +0000[diff] [blame]5129
5130<p>Note that the code generator does not yet support vector types with
5131 the <tt>icmp</tt> instruction.</p>
5132
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5133</div>
5134
5135<!-- _______________________________________________________________________ -->
5136<div class="doc_subsubsection"><a name="i_fcmp">'<tt>fcmp</tt>' Instruction</a>
5137</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5138
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5139<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5140
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5141<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5142<pre>
5143 &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]5144</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5145
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5146<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5147<p>The '<tt>fcmp</tt>' instruction returns a boolean value or vector of boolean
5148 values based on comparison of its operands.</p>
5149
5150<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]5151(<a href="#t_integer"><tt>i1</tt></a>).</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5152
5153<p>If the operands are floating point vectors, then the result type is a vector
5154 of boolean with the same number of elements as the operands being
5155 compared.</p>
5156
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5157<h5>Arguments:</h5>
5158<p>The '<tt>fcmp</tt>' instruction takes three operands. The first operand is
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5159 the condition code indicating the kind of comparison to perform. It is not a
5160 value, just a keyword. The possible condition code are:</p>
5161
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5162<ol>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]5163 <li><tt>false</tt>: no comparison, always returns false</li>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5164 <li><tt>oeq</tt>: ordered and equal</li>
5165 <li><tt>ogt</tt>: ordered and greater than </li>
5166 <li><tt>oge</tt>: ordered and greater than or equal</li>
5167 <li><tt>olt</tt>: ordered and less than </li>
5168 <li><tt>ole</tt>: ordered and less than or equal</li>
5169 <li><tt>one</tt>: ordered and not equal</li>
5170 <li><tt>ord</tt>: ordered (no nans)</li>
5171 <li><tt>ueq</tt>: unordered or equal</li>
5172 <li><tt>ugt</tt>: unordered or greater than </li>
5173 <li><tt>uge</tt>: unordered or greater than or equal</li>
5174 <li><tt>ult</tt>: unordered or less than </li>
5175 <li><tt>ule</tt>: unordered or less than or equal</li>
5176 <li><tt>une</tt>: unordered or not equal</li>
5177 <li><tt>uno</tt>: unordered (either nans)</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]5178 <li><tt>true</tt>: no comparison, always returns true</li>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5179</ol>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5180
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5181<p><i>Ordered</i> means that neither operand is a QNAN while
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5182 <i>unordered</i> means that either operand may be a QNAN.</p>
5183
5184<p>Each of <tt>val1</tt> and <tt>val2</tt> arguments must be either
5185 a <a href="#t_floating">floating point</a> type or
5186 a <a href="#t_vector">vector</a> of floating point type. They must have
5187 identical types.</p>
5188
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5189<h5>Semantics:</h5>
Gabor Greif0f75ad02008-08-07 21:46:00 +0000[diff] [blame]5190<p>The '<tt>fcmp</tt>' instruction compares <tt>op1</tt> and <tt>op2</tt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5191 according to the condition code given as <tt>cond</tt>. If the operands are
5192 vectors, then the vectors are compared element by element. Each comparison
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]5193 performed always yields an <a href="#t_integer">i1</a> result, as
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5194 follows:</p>
5195
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5196<ol>
5197 <li><tt>false</tt>: always yields <tt>false</tt>, regardless of operands.</li>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5198
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5199 <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]5200 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
5201
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]5202 <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]5203 <tt>op1</tt> is greater than <tt>op2</tt>.</li>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5204
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5205 <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]5206 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
5207
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5208 <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]5209 <tt>op1</tt> is less than <tt>op2</tt>.</li>
5210
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5211 <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]5212 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
5213
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5214 <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]5215 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
5216
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]5217 <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]5218
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5219 <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]5220 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
5221
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5222 <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]5223 <tt>op1</tt> is greater than <tt>op2</tt>.</li>
5224
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5225 <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]5226 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
5227
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5228 <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]5229 <tt>op1</tt> is less than <tt>op2</tt>.</li>
5230
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5231 <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]5232 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
5233
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5234 <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]5235 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
5236
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]5237 <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]5238
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5239 <li><tt>true</tt>: always yields <tt>true</tt>, regardless of operands.</li>
5240</ol>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5241
5242<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5243<pre>
5244 &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]5245 &lt;result&gt; = fcmp one float 4.0, 5.0 <i>; yields: result=true</i>
5246 &lt;result&gt; = fcmp olt float 4.0, 5.0 <i>; yields: result=true</i>
5247 &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]5248</pre>
Dan Gohmana5127ab2009-01-22 01:39:38 +0000[diff] [blame]5249
5250<p>Note that the code generator does not yet support vector types with
5251 the <tt>fcmp</tt> instruction.</p>
5252
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5253</div>
5254
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5255<!-- _______________________________________________________________________ -->
Nate Begemand2195702008-05-12 19:01:56 +0000[diff] [blame]5256<div class="doc_subsubsection">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]5257 <a name="i_phi">'<tt>phi</tt>' Instruction</a>
5258</div>
5259
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5260<div class="doc_text">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]5261
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5262<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5263<pre>
5264 &lt;result&gt; = phi &lt;ty&gt; [ &lt;val0&gt;, &lt;label0&gt;], ...
5265</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]5266
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5267<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5268<p>The '<tt>phi</tt>' instruction is used to implement the &#966; node in the
5269 SSA graph representing the function.</p>
5270
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5271<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5272<p>The type of the incoming values is specified with the first type field. After
5273 this, the '<tt>phi</tt>' instruction takes a list of pairs as arguments, with
5274 one pair for each predecessor basic block of the current block. Only values
5275 of <a href="#t_firstclass">first class</a> type may be used as the value
5276 arguments to the PHI node. Only labels may be used as the label
5277 arguments.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]5278
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5279<p>There must be no non-phi instructions between the start of a basic block and
5280 the PHI instructions: i.e. PHI instructions must be first in a basic
5281 block.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]5282
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5283<p>For the purposes of the SSA form, the use of each incoming value is deemed to
5284 occur on the edge from the corresponding predecessor block to the current
5285 block (but after any definition of an '<tt>invoke</tt>' instruction's return
5286 value on the same edge).</p>
Jay Foad1a4eea52009-06-03 10:20:10 +0000[diff] [blame]5287
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5288<h5>Semantics:</h5>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5289<p>At runtime, the '<tt>phi</tt>' instruction logically takes on the value
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5290 specified by the pair corresponding to the predecessor basic block that
5291 executed just prior to the current block.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]5292
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5293<h5>Example:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]5294<pre>
5295Loop: ; Infinite loop that counts from 0 on up...
5296 %indvar = phi i32 [ 0, %LoopHeader ], [ %nextindvar, %Loop ]
5297 %nextindvar = add i32 %indvar, 1
5298 br label %Loop
5299</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5300
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5301</div>
5302
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5303<!-- _______________________________________________________________________ -->
5304<div class="doc_subsubsection">
5305 <a name="i_select">'<tt>select</tt>' Instruction</a>
5306</div>
5307
5308<div class="doc_text">
5309
5310<h5>Syntax:</h5>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5311<pre>
Dan Gohmanc579d972008-09-09 01:02:47 +0000[diff] [blame]5312 &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>
5313
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]5314 <i>selty</i> is either i1 or {&lt;N x i1&gt;}
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5315</pre>
5316
5317<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5318<p>The '<tt>select</tt>' instruction is used to choose one value based on a
5319 condition, without branching.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5320
5321
5322<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5323<p>The '<tt>select</tt>' instruction requires an 'i1' value or a vector of 'i1'
5324 values indicating the condition, and two values of the
5325 same <a href="#t_firstclass">first class</a> type. If the val1/val2 are
5326 vectors and the condition is a scalar, then entire vectors are selected, not
5327 individual elements.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5328
5329<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5330<p>If the condition is an i1 and it evaluates to 1, the instruction returns the
5331 first value argument; otherwise, it returns the second value argument.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5332
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5333<p>If the condition is a vector of i1, then the value arguments must be vectors
5334 of the same size, and the selection is done element by element.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5335
5336<h5>Example:</h5>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5337<pre>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]5338 %X = select i1 true, i8 17, i8 42 <i>; yields i8:17</i>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5339</pre>
Dan Gohmana5127ab2009-01-22 01:39:38 +0000[diff] [blame]5340
5341<p>Note that the code generator does not yet support conditions
5342 with vector type.</p>
5343
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5344</div>
5345
Robert Bocchinof72fdfe2006-01-15 20:48:27 +0000[diff] [blame]5346<!-- _______________________________________________________________________ -->
5347<div class="doc_subsubsection">
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5348 <a name="i_call">'<tt>call</tt>' Instruction</a>
5349</div>
5350
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5351<div class="doc_text">
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5352
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]5353<h5>Syntax:</h5>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5354<pre>
Devang Patel02256232008-10-07 17:48:33 +0000[diff] [blame]5355 &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]5356</pre>
5357
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]5358<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5359<p>The '<tt>call</tt>' instruction represents a simple function call.</p>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5360
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]5361<h5>Arguments:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5362<p>This instruction requires several arguments:</p>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5363
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]5364<ol>
Jeffrey Yasskinb8677462010-01-09 19:44:16 +0000[diff] [blame]5365 <li>The optional "tail" marker indicates that the callee function does not
5366 access any allocas or varargs in the caller. Note that calls may be
5367 marked "tail" even if they do not occur before
5368 a <a href="#i_ret"><tt>ret</tt></a> instruction. If the "tail" marker is
5369 present, the function call is eligible for tail call optimization,
5370 but <a href="CodeGenerator.html#tailcallopt">might not in fact be
Evan Cheng59676492010-03-08 21:05:02 +0000[diff] [blame]5371 optimized into a jump</a>. The code generator may optimize calls marked
5372 "tail" with either 1) automatic <a href="CodeGenerator.html#sibcallopt">
5373 sibling call optimization</a> when the caller and callee have
5374 matching signatures, or 2) forced tail call optimization when the
5375 following extra requirements are met:
Jeffrey Yasskinb8677462010-01-09 19:44:16 +0000[diff] [blame]5376 <ul>
5377 <li>Caller and callee both have the calling
5378 convention <tt>fastcc</tt>.</li>
5379 <li>The call is in tail position (ret immediately follows call and ret
5380 uses value of call or is void).</li>
5381 <li>Option <tt>-tailcallopt</tt> is enabled,
Dan Gohman6232f732010-03-02 01:08:11 +0000[diff] [blame]5382 or <code>llvm::GuaranteedTailCallOpt</code> is <code>true</code>.</li>
Jeffrey Yasskinb8677462010-01-09 19:44:16 +0000[diff] [blame]5383 <li><a href="CodeGenerator.html#tailcallopt">Platform specific
5384 constraints are met.</a></li>
5385 </ul>
5386 </li>
Devang Patel7e9b05e2008-10-06 18:50:38 +0000[diff] [blame]5387
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5388 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
5389 convention</a> the call should use. If none is specified, the call
Jeffrey Yasskinb8677462010-01-09 19:44:16 +0000[diff] [blame]5390 defaults to using C calling conventions. The calling convention of the
5391 call must match the calling convention of the target function, or else the
5392 behavior is undefined.</li>
Devang Patel7e9b05e2008-10-06 18:50:38 +0000[diff] [blame]5393
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5394 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
5395 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
5396 '<tt>inreg</tt>' attributes are valid here.</li>
5397
5398 <li>'<tt>ty</tt>': the type of the call instruction itself which is also the
5399 type of the return value. Functions that return no value are marked
5400 <tt><a href="#t_void">void</a></tt>.</li>
5401
5402 <li>'<tt>fnty</tt>': shall be the signature of the pointer to function value
5403 being invoked. The argument types must match the types implied by this
5404 signature. This type can be omitted if the function is not varargs and if
5405 the function type does not return a pointer to a function.</li>
5406
5407 <li>'<tt>fnptrval</tt>': An LLVM value containing a pointer to a function to
5408 be invoked. In most cases, this is a direct function invocation, but
5409 indirect <tt>call</tt>s are just as possible, calling an arbitrary pointer
5410 to function value.</li>
5411
5412 <li>'<tt>function args</tt>': argument list whose types match the function
Chris Lattner47f2a832010-03-02 06:36:51 +0000[diff] [blame]5413 signature argument types and parameter attributes. All arguments must be
5414 of <a href="#t_firstclass">first class</a> type. If the function
5415 signature indicates the function accepts a variable number of arguments,
5416 the extra arguments can be specified.</li>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5417
5418 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
5419 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
5420 '<tt>readnone</tt>' attributes are valid here.</li>
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]5421</ol>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5422
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]5423<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5424<p>The '<tt>call</tt>' instruction is used to cause control flow to transfer to
5425 a specified function, with its incoming arguments bound to the specified
5426 values. Upon a '<tt><a href="#i_ret">ret</a></tt>' instruction in the called
5427 function, control flow continues with the instruction after the function
5428 call, and the return value of the function is bound to the result
5429 argument.</p>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5430
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]5431<h5>Example:</h5>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5432<pre>
Nick Lewyckya9b13d52007-09-08 13:57:50 +0000[diff] [blame]5433 %retval = call i32 @test(i32 %argc)
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]5434 call i32 (i8*, ...)* @printf(i8* %msg, i32 12, i8 42) <i>; yields i32</i>
Chris Lattnerfb7c88d2008-03-21 17:24:17 +0000[diff] [blame]5435 %X = tail call i32 @foo() <i>; yields i32</i>
5436 %Y = tail call <a href="#callingconv">fastcc</a> i32 @foo() <i>; yields i32</i>
5437 call void %foo(i8 97 signext)
Devang Pateld6cff512008-03-10 20:49:15 +0000[diff] [blame]5438
5439 %struct.A = type { i32, i8 }
Devang Patel7e9b05e2008-10-06 18:50:38 +0000[diff] [blame]5440 %r = call %struct.A @foo() <i>; yields { 32, i8 }</i>
Dan Gohmancc3132e2008-10-04 19:00:07 +0000[diff] [blame]5441 %gr = extractvalue %struct.A %r, 0 <i>; yields i32</i>
5442 %gr1 = extractvalue %struct.A %r, 1 <i>; yields i8</i>
Chris Lattner6cbe8e92008-10-08 06:26:11 +0000[diff] [blame]5443 %Z = call void @foo() noreturn <i>; indicates that %foo never returns normally</i>
Matthijs Kooijmaneefa7df2008-10-07 10:03:45 +0000[diff] [blame]5444 %ZZ = call zeroext i32 @bar() <i>; Return value is %zero extended</i>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5445</pre>
5446
Dale Johannesen68f971b2009-09-24 18:38:21 +0000[diff] [blame]5447<p>llvm treats calls to some functions with names and arguments that match the
Dale Johannesen722212d2009-09-25 17:04:42 +0000[diff] [blame]5448standard C99 library as being the C99 library functions, and may perform
5449optimizations or generate code for them under that assumption. This is
5450something we'd like to change in the future to provide better support for
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]5451freestanding environments and non-C-based languages.</p>
Dale Johannesen68f971b2009-09-24 18:38:21 +0000[diff] [blame]5452
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5453</div>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5454
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5455<!-- _______________________________________________________________________ -->
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5456<div class="doc_subsubsection">
Chris Lattner33337472006-01-13 23:26:01 +0000[diff] [blame]5457 <a name="i_va_arg">'<tt>va_arg</tt>' Instruction</a>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5458</div>
5459
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5460<div class="doc_text">
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5461
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]5462<h5>Syntax:</h5>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5463<pre>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]5464 &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]5465</pre>
5466
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]5467<h5>Overview:</h5>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]5468<p>The '<tt>va_arg</tt>' instruction is used to access arguments passed through
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5469 the "variable argument" area of a function call. It is used to implement the
5470 <tt>va_arg</tt> macro in C.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5471
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]5472<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5473<p>This instruction takes a <tt>va_list*</tt> value and the type of the
5474 argument. It returns a value of the specified argument type and increments
5475 the <tt>va_list</tt> to point to the next argument. The actual type
5476 of <tt>va_list</tt> is target specific.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5477
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]5478<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5479<p>The '<tt>va_arg</tt>' instruction loads an argument of the specified type
5480 from the specified <tt>va_list</tt> and causes the <tt>va_list</tt> to point
5481 to the next argument. For more information, see the variable argument
5482 handling <a href="#int_varargs">Intrinsic Functions</a>.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5483
5484<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]5485 take a variable number of arguments, for example, the <tt>vfprintf</tt>
5486 function.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5487
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5488<p><tt>va_arg</tt> is an LLVM instruction instead of
5489 an <a href="#intrinsics">intrinsic function</a> because it takes a type as an
5490 argument.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5491
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]5492<h5>Example:</h5>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5493<p>See the <a href="#int_varargs">variable argument processing</a> section.</p>
5494
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5495<p>Note that the code generator does not yet fully support va_arg on many
5496 targets. Also, it does not currently support va_arg with aggregate types on
5497 any target.</p>
Dan Gohman3065b612009-01-12 23:12:39 +0000[diff] [blame]5498
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5499</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5500
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5501<!-- *********************************************************************** -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]5502<div class="doc_section"> <a name="intrinsics">Intrinsic Functions</a> </div>
5503<!-- *********************************************************************** -->
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5504
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5505<div class="doc_text">
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5506
5507<p>LLVM supports the notion of an "intrinsic function". These functions have
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5508 well known names and semantics and are required to follow certain
5509 restrictions. Overall, these intrinsics represent an extension mechanism for
5510 the LLVM language that does not require changing all of the transformations
5511 in LLVM when adding to the language (or the bitcode reader/writer, the
5512 parser, etc...).</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5513
John Criswell88190562005-05-16 16:17:45 +0000[diff] [blame]5514<p>Intrinsic function names must all start with an "<tt>llvm.</tt>" prefix. This
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5515 prefix is reserved in LLVM for intrinsic names; thus, function names may not
5516 begin with this prefix. Intrinsic functions must always be external
5517 functions: you cannot define the body of intrinsic functions. Intrinsic
5518 functions may only be used in call or invoke instructions: it is illegal to
5519 take the address of an intrinsic function. Additionally, because intrinsic
5520 functions are part of the LLVM language, it is required if any are added that
5521 they be documented here.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5522
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5523<p>Some intrinsic functions can be overloaded, i.e., the intrinsic represents a
5524 family of functions that perform the same operation but on different data
5525 types. Because LLVM can represent over 8 million different integer types,
5526 overloading is used commonly to allow an intrinsic function to operate on any
5527 integer type. One or more of the argument types or the result type can be
5528 overloaded to accept any integer type. Argument types may also be defined as
5529 exactly matching a previous argument's type or the result type. This allows
5530 an intrinsic function which accepts multiple arguments, but needs all of them
5531 to be of the same type, to only be overloaded with respect to a single
5532 argument or the result.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5533
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5534<p>Overloaded intrinsics will have the names of its overloaded argument types
5535 encoded into its function name, each preceded by a period. Only those types
5536 which are overloaded result in a name suffix. Arguments whose type is matched
5537 against another type do not. For example, the <tt>llvm.ctpop</tt> function
5538 can take an integer of any width and returns an integer of exactly the same
5539 integer width. This leads to a family of functions such as
5540 <tt>i8 @llvm.ctpop.i8(i8 %val)</tt> and <tt>i29 @llvm.ctpop.i29(i29
5541 %val)</tt>. Only one type, the return type, is overloaded, and only one type
5542 suffix is required. Because the argument's type is matched against the return
5543 type, it does not require its own name suffix.</p>
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]5544
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5545<p>To learn how to add an intrinsic function, please see the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5546 <a href="ExtendingLLVM.html">Extending LLVM Guide</a>.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5547
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5548</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5549
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5550<!-- ======================================================================= -->
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5551<div class="doc_subsection">
5552 <a name="int_varargs">Variable Argument Handling Intrinsics</a>
5553</div>
5554
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5555<div class="doc_text">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5556
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5557<p>Variable argument support is defined in LLVM with
5558 the <a href="#i_va_arg"><tt>va_arg</tt></a> instruction and these three
5559 intrinsic functions. These functions are related to the similarly named
5560 macros defined in the <tt>&lt;stdarg.h&gt;</tt> header file.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5561
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5562<p>All of these functions operate on arguments that use a target-specific value
5563 type "<tt>va_list</tt>". The LLVM assembly language reference manual does
5564 not define what this type is, so all transformations should be prepared to
5565 handle these functions regardless of the type used.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5566
Chris Lattner30b868d2006-05-15 17:26:46 +0000[diff] [blame]5567<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]5568 instruction and the variable argument handling intrinsic functions are
5569 used.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5570
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]5571<pre class="doc_code">
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]5572define i32 @test(i32 %X, ...) {
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5573 ; Initialize variable argument processing
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5574 %ap = alloca i8*
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]5575 %ap2 = bitcast i8** %ap to i8*
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]5576 call void @llvm.va_start(i8* %ap2)
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5577
5578 ; Read a single integer argument
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5579 %tmp = va_arg i8** %ap, i32
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5580
5581 ; Demonstrate usage of llvm.va_copy and llvm.va_end
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5582 %aq = alloca i8*
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]5583 %aq2 = bitcast i8** %aq to i8*
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5584 call void @llvm.va_copy(i8* %aq2, i8* %ap2)
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]5585 call void @llvm.va_end(i8* %aq2)
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5586
5587 ; Stop processing of arguments.
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]5588 call void @llvm.va_end(i8* %ap2)
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]5589 ret i32 %tmp
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5590}
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]5591
5592declare void @llvm.va_start(i8*)
5593declare void @llvm.va_copy(i8*, i8*)
5594declare void @llvm.va_end(i8*)
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5595</pre>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5596
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]5597</div>
5598
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5599<!-- _______________________________________________________________________ -->
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5600<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5601 <a name="int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5602</div>
5603
5604
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5605<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5606
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5607<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5608<pre>
5609 declare void %llvm.va_start(i8* &lt;arglist&gt;)
5610</pre>
5611
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5612<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5613<p>The '<tt>llvm.va_start</tt>' intrinsic initializes <tt>*&lt;arglist&gt;</tt>
5614 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]5615
5616<h5>Arguments:</h5>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]5617<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]5618
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5619<h5>Semantics:</h5>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]5620<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]5621 macro available in C. In a target-dependent way, it initializes
5622 the <tt>va_list</tt> element to which the argument points, so that the next
5623 call to <tt>va_arg</tt> will produce the first variable argument passed to
5624 the function. Unlike the C <tt>va_start</tt> macro, this intrinsic does not
5625 need to know the last argument of the function as the compiler can figure
5626 that out.</p>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]5627
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5628</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5629
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5630<!-- _______________________________________________________________________ -->
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5631<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5632 <a name="int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5633</div>
5634
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5635<div class="doc_text">
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]5636
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5637<h5>Syntax:</h5>
5638<pre>
5639 declare void @llvm.va_end(i8* &lt;arglist&gt;)
5640</pre>
5641
5642<h5>Overview:</h5>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5643<p>The '<tt>llvm.va_end</tt>' intrinsic destroys <tt>*&lt;arglist&gt;</tt>,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5644 which has been initialized previously
5645 with <tt><a href="#int_va_start">llvm.va_start</a></tt>
5646 or <tt><a href="#i_va_copy">llvm.va_copy</a></tt>.</p>
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]5647
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5648<h5>Arguments:</h5>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5649<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]5650
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5651<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5652<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]5653 macro available in C. In a target-dependent way, it destroys
5654 the <tt>va_list</tt> element to which the argument points. Calls
5655 to <a href="#int_va_start"><tt>llvm.va_start</tt></a>
5656 and <a href="#int_va_copy"> <tt>llvm.va_copy</tt></a> must be matched exactly
5657 with calls to <tt>llvm.va_end</tt>.</p>
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]5658
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5659</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5660
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5661<!-- _______________________________________________________________________ -->
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5662<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5663 <a name="int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5664</div>
5665
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5666<div class="doc_text">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5667
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5668<h5>Syntax:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5669<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]5670 declare void @llvm.va_copy(i8* &lt;destarglist&gt;, i8* &lt;srcarglist&gt;)
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5671</pre>
5672
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5673<h5>Overview:</h5>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5674<p>The '<tt>llvm.va_copy</tt>' intrinsic copies the current argument position
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5675 from the source argument list to the destination argument list.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5676
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5677<h5>Arguments:</h5>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]5678<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]5679 The second argument is a pointer to a <tt>va_list</tt> element to copy
5680 from.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5681
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5682<h5>Semantics:</h5>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5683<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]5684 macro available in C. In a target-dependent way, it copies the
5685 source <tt>va_list</tt> element into the destination <tt>va_list</tt>
5686 element. This intrinsic is necessary because
5687 the <tt><a href="#int_va_start"> llvm.va_start</a></tt> intrinsic may be
5688 arbitrarily complex and require, for example, memory allocation.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5689
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5690</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5691
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5692<!-- ======================================================================= -->
5693<div class="doc_subsection">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5694 <a name="int_gc">Accurate Garbage Collection Intrinsics</a>
5695</div>
5696
5697<div class="doc_text">
5698
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5699<p>LLVM support for <a href="GarbageCollection.html">Accurate Garbage
Chris Lattner67c37d12008-08-05 18:29:16 +0000[diff] [blame]5700Collection</a> (GC) requires the implementation and generation of these
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5701intrinsics. These intrinsics allow identification of <a href="#int_gcroot">GC
5702roots on the stack</a>, as well as garbage collector implementations that
5703require <a href="#int_gcread">read</a> and <a href="#int_gcwrite">write</a>
5704barriers. Front-ends for type-safe garbage collected languages should generate
5705these intrinsics to make use of the LLVM garbage collectors. For more details,
5706see <a href="GarbageCollection.html">Accurate Garbage Collection with
5707LLVM</a>.</p>
Christopher Lamb55c6d4f2007-12-17 01:00:21 +0000[diff] [blame]5708
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5709<p>The garbage collection intrinsics only operate on objects in the generic
5710 address space (address space zero).</p>
Christopher Lamb55c6d4f2007-12-17 01:00:21 +0000[diff] [blame]5711
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5712</div>
5713
5714<!-- _______________________________________________________________________ -->
5715<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5716 <a name="int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5717</div>
5718
5719<div class="doc_text">
5720
5721<h5>Syntax:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5722<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]5723 declare void @llvm.gcroot(i8** %ptrloc, i8* %metadata)
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5724</pre>
5725
5726<h5>Overview:</h5>
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]5727<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]5728 the code generator, and allows some metadata to be associated with it.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5729
5730<h5>Arguments:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5731<p>The first argument specifies the address of a stack object that contains the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5732 root pointer. The second pointer (which must be either a constant or a
5733 global value address) contains the meta-data to be associated with the
5734 root.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5735
5736<h5>Semantics:</h5>
Chris Lattner851b7712008-04-24 05:59:56 +0000[diff] [blame]5737<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]5738 location. At compile-time, the code generator generates information to allow
5739 the runtime to find the pointer at GC safe points. The '<tt>llvm.gcroot</tt>'
5740 intrinsic may only be used in a function which <a href="#gc">specifies a GC
5741 algorithm</a>.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5742
5743</div>
5744
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5745<!-- _______________________________________________________________________ -->
5746<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5747 <a name="int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5748</div>
5749
5750<div class="doc_text">
5751
5752<h5>Syntax:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5753<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]5754 declare i8* @llvm.gcread(i8* %ObjPtr, i8** %Ptr)
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5755</pre>
5756
5757<h5>Overview:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5758<p>The '<tt>llvm.gcread</tt>' intrinsic identifies reads of references from heap
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5759 locations, allowing garbage collector implementations that require read
5760 barriers.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5761
5762<h5>Arguments:</h5>
Chris Lattnerf9228072006-03-14 20:02:51 +0000[diff] [blame]5763<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]5764 allocated from the garbage collector. The first object is a pointer to the
5765 start of the referenced object, if needed by the language runtime (otherwise
5766 null).</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5767
5768<h5>Semantics:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5769<p>The '<tt>llvm.gcread</tt>' intrinsic has the same semantics as a load
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5770 instruction, but may be replaced with substantially more complex code by the
5771 garbage collector runtime, as needed. The '<tt>llvm.gcread</tt>' intrinsic
5772 may only be used in a function which <a href="#gc">specifies a GC
5773 algorithm</a>.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5774
5775</div>
5776
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5777<!-- _______________________________________________________________________ -->
5778<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5779 <a name="int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5780</div>
5781
5782<div class="doc_text">
5783
5784<h5>Syntax:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5785<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]5786 declare void @llvm.gcwrite(i8* %P1, i8* %Obj, i8** %P2)
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5787</pre>
5788
5789<h5>Overview:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5790<p>The '<tt>llvm.gcwrite</tt>' intrinsic identifies writes of references to heap
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5791 locations, allowing garbage collector implementations that require write
5792 barriers (such as generational or reference counting collectors).</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5793
5794<h5>Arguments:</h5>
Chris Lattnerf9228072006-03-14 20:02:51 +0000[diff] [blame]5795<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]5796 object to store it to, and the third is the address of the field of Obj to
5797 store to. If the runtime does not require a pointer to the object, Obj may
5798 be null.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5799
5800<h5>Semantics:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5801<p>The '<tt>llvm.gcwrite</tt>' intrinsic has the same semantics as a store
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5802 instruction, but may be replaced with substantially more complex code by the
5803 garbage collector runtime, as needed. The '<tt>llvm.gcwrite</tt>' intrinsic
5804 may only be used in a function which <a href="#gc">specifies a GC
5805 algorithm</a>.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5806
5807</div>
5808
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5809<!-- ======================================================================= -->
5810<div class="doc_subsection">
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5811 <a name="int_codegen">Code Generator Intrinsics</a>
5812</div>
5813
5814<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5815
5816<p>These intrinsics are provided by LLVM to expose special features that may
5817 only be implemented with code generator support.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5818
5819</div>
5820
5821<!-- _______________________________________________________________________ -->
5822<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5823 <a name="int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5824</div>
5825
5826<div class="doc_text">
5827
5828<h5>Syntax:</h5>
5829<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]5830 declare i8 *@llvm.returnaddress(i32 &lt;level&gt;)
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5831</pre>
5832
5833<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5834<p>The '<tt>llvm.returnaddress</tt>' intrinsic attempts to compute a
5835 target-specific value indicating the return address of the current function
5836 or one of its callers.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5837
5838<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5839<p>The argument to this intrinsic indicates which function to return the address
5840 for. Zero indicates the calling function, one indicates its caller, etc.
5841 The argument is <b>required</b> to be a constant integer value.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5842
5843<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5844<p>The '<tt>llvm.returnaddress</tt>' intrinsic either returns a pointer
5845 indicating the return address of the specified call frame, or zero if it
5846 cannot be identified. The value returned by this intrinsic is likely to be
5847 incorrect or 0 for arguments other than zero, so it should only be used for
5848 debugging purposes.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5849
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5850<p>Note that calling this intrinsic does not prevent function inlining or other
5851 aggressive transformations, so the value returned may not be that of the
5852 obvious source-language caller.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5853
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5854</div>
5855
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5856<!-- _______________________________________________________________________ -->
5857<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5858 <a name="int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5859</div>
5860
5861<div class="doc_text">
5862
5863<h5>Syntax:</h5>
5864<pre>
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]5865 declare i8* @llvm.frameaddress(i32 &lt;level&gt;)
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5866</pre>
5867
5868<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5869<p>The '<tt>llvm.frameaddress</tt>' intrinsic attempts to return the
5870 target-specific frame pointer value for the specified stack frame.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5871
5872<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5873<p>The argument to this intrinsic indicates which function to return the frame
5874 pointer for. Zero indicates the calling function, one indicates its caller,
5875 etc. The argument is <b>required</b> to be a constant integer value.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5876
5877<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5878<p>The '<tt>llvm.frameaddress</tt>' intrinsic either returns a pointer
5879 indicating the frame address of the specified call frame, or zero if it
5880 cannot be identified. The value returned by this intrinsic is likely to be
5881 incorrect or 0 for arguments other than zero, so it should only be used for
5882 debugging purposes.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5883
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5884<p>Note that calling this intrinsic does not prevent function inlining or other
5885 aggressive transformations, so the value returned may not be that of the
5886 obvious source-language caller.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5887
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5888</div>
5889
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]5890<!-- _______________________________________________________________________ -->
5891<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5892 <a name="int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]5893</div>
5894
5895<div class="doc_text">
5896
5897<h5>Syntax:</h5>
5898<pre>
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]5899 declare i8* @llvm.stacksave()
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]5900</pre>
5901
5902<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5903<p>The '<tt>llvm.stacksave</tt>' intrinsic is used to remember the current state
5904 of the function stack, for use
5905 with <a href="#int_stackrestore"> <tt>llvm.stackrestore</tt></a>. This is
5906 useful for implementing language features like scoped automatic variable
5907 sized arrays in C99.</p>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]5908
5909<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5910<p>This intrinsic returns a opaque pointer value that can be passed
5911 to <a href="#int_stackrestore"><tt>llvm.stackrestore</tt></a>. When
5912 an <tt>llvm.stackrestore</tt> intrinsic is executed with a value saved
5913 from <tt>llvm.stacksave</tt>, it effectively restores the state of the stack
5914 to the state it was in when the <tt>llvm.stacksave</tt> intrinsic executed.
5915 In practice, this pops any <a href="#i_alloca">alloca</a> blocks from the
5916 stack that were allocated after the <tt>llvm.stacksave</tt> was executed.</p>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]5917
5918</div>
5919
5920<!-- _______________________________________________________________________ -->
5921<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5922 <a name="int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]5923</div>
5924
5925<div class="doc_text">
5926
5927<h5>Syntax:</h5>
5928<pre>
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]5929 declare void @llvm.stackrestore(i8* %ptr)
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]5930</pre>
5931
5932<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5933<p>The '<tt>llvm.stackrestore</tt>' intrinsic is used to restore the state of
5934 the function stack to the state it was in when the
5935 corresponding <a href="#int_stacksave"><tt>llvm.stacksave</tt></a> intrinsic
5936 executed. This is useful for implementing language features like scoped
5937 automatic variable sized arrays in C99.</p>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]5938
5939<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5940<p>See the description
5941 for <a href="#int_stacksave"><tt>llvm.stacksave</tt></a>.</p>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]5942
5943</div>
5944
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]5945<!-- _______________________________________________________________________ -->
5946<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5947 <a name="int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a>
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]5948</div>
5949
5950<div class="doc_text">
5951
5952<h5>Syntax:</h5>
5953<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]5954 declare void @llvm.prefetch(i8* &lt;address&gt;, i32 &lt;rw&gt;, i32 &lt;locality&gt;)
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]5955</pre>
5956
5957<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5958<p>The '<tt>llvm.prefetch</tt>' intrinsic is a hint to the code generator to
5959 insert a prefetch instruction if supported; otherwise, it is a noop.
5960 Prefetches have no effect on the behavior of the program but can change its
5961 performance characteristics.</p>
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]5962
5963<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5964<p><tt>address</tt> is the address to be prefetched, <tt>rw</tt> is the
5965 specifier determining if the fetch should be for a read (0) or write (1),
5966 and <tt>locality</tt> is a temporal locality specifier ranging from (0) - no
5967 locality, to (3) - extremely local keep in cache. The <tt>rw</tt>
5968 and <tt>locality</tt> arguments must be constant integers.</p>
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]5969
5970<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5971<p>This intrinsic does not modify the behavior of the program. In particular,
5972 prefetches cannot trap and do not produce a value. On targets that support
5973 this intrinsic, the prefetch can provide hints to the processor cache for
5974 better performance.</p>
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]5975
5976</div>
5977
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]5978<!-- _______________________________________________________________________ -->
5979<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5980 <a name="int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a>
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]5981</div>
5982
5983<div class="doc_text">
5984
5985<h5>Syntax:</h5>
5986<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]5987 declare void @llvm.pcmarker(i32 &lt;id&gt;)
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]5988</pre>
5989
5990<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5991<p>The '<tt>llvm.pcmarker</tt>' intrinsic is a method to export a Program
5992 Counter (PC) in a region of code to simulators and other tools. The method
5993 is target specific, but it is expected that the marker will use exported
5994 symbols to transmit the PC of the marker. The marker makes no guarantees
5995 that it will remain with any specific instruction after optimizations. It is
5996 possible that the presence of a marker will inhibit optimizations. The
5997 intended use is to be inserted after optimizations to allow correlations of
5998 simulation runs.</p>
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]5999
6000<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6001<p><tt>id</tt> is a numerical id identifying the marker.</p>
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]6002
6003<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6004<p>This intrinsic does not modify the behavior of the program. Backends that do
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]6005 not support this intrinsic may ignore it.</p>
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]6006
6007</div>
6008
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]6009<!-- _______________________________________________________________________ -->
6010<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6011 <a name="int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a>
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]6012</div>
6013
6014<div class="doc_text">
6015
6016<h5>Syntax:</h5>
6017<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]6018 declare i64 @llvm.readcyclecounter()
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]6019</pre>
6020
6021<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6022<p>The '<tt>llvm.readcyclecounter</tt>' intrinsic provides access to the cycle
6023 counter register (or similar low latency, high accuracy clocks) on those
6024 targets that support it. On X86, it should map to RDTSC. On Alpha, it
6025 should map to RPCC. As the backing counters overflow quickly (on the order
6026 of 9 seconds on alpha), this should only be used for small timings.</p>
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]6027
6028<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6029<p>When directly supported, reading the cycle counter should not modify any
6030 memory. Implementations are allowed to either return a application specific
6031 value or a system wide value. On backends without support, this is lowered
6032 to a constant 0.</p>
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]6033
6034</div>
6035
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6036<!-- ======================================================================= -->
6037<div class="doc_subsection">
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6038 <a name="int_libc">Standard C Library Intrinsics</a>
6039</div>
6040
6041<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6042
6043<p>LLVM provides intrinsics for a few important standard C library functions.
6044 These intrinsics allow source-language front-ends to pass information about
6045 the alignment of the pointer arguments to the code generator, providing
6046 opportunity for more efficient code generation.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6047
6048</div>
6049
6050<!-- _______________________________________________________________________ -->
6051<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6052 <a name="int_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6053</div>
6054
6055<div class="doc_text">
6056
6057<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6058<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]6059 integer bit width and for different address spaces. Not all targets support
6060 all bit widths however.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6061
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6062<pre>
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]6063 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]6064 i32 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]6065 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]6066 i64 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6067</pre>
6068
6069<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6070<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
6071 source location to the destination location.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6072
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6073<p>Note that, unlike the standard libc function, the <tt>llvm.memcpy.*</tt>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6074 intrinsics do not return a value, takes extra alignment/isvolatile arguments
6075 and the pointers can be in specified address spaces.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6076
6077<h5>Arguments:</h5>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6078
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6079<p>The first argument is a pointer to the destination, the second is a pointer
6080 to the source. The third argument is an integer argument specifying the
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6081 number of bytes to copy, the fourth argument is the alignment of the
6082 source and destination locations, and the fifth is a boolean indicating a
6083 volatile access.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6084
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]6085<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]6086 then the caller guarantees that both the source and destination pointers are
6087 aligned to that boundary.</p>
Chris Lattner4c67c482004-02-12 21:18:15 +0000[diff] [blame]6088
Jeffrey Yasskin5d284ae2010-04-26 21:21:24 +0000[diff] [blame]6089<p>If the <tt>isvolatile</tt> parameter is <tt>true</tt>, the
6090 <tt>llvm.memcpy</tt> call is a <a href="#volatile">volatile operation</a>.
6091 The detailed access behavior is not very cleanly specified and it is unwise
6092 to depend on it.</p>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6093
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6094<h5>Semantics:</h5>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6095
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6096<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
6097 source location to the destination location, which are not allowed to
6098 overlap. It copies "len" bytes of memory over. If the argument is known to
6099 be aligned to some boundary, this can be specified as the fourth argument,
6100 otherwise it should be set to 0 or 1.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6101
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6102</div>
6103
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6104<!-- _______________________________________________________________________ -->
6105<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6106 <a name="int_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a>
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6107</div>
6108
6109<div class="doc_text">
6110
6111<h5>Syntax:</h5>
Chris Lattnerdd708342008-11-21 16:42:48 +0000[diff] [blame]6112<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]6113 width and for different address space. Not all targets support all bit
6114 widths however.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6115
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6116<pre>
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]6117 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]6118 i32 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]6119 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]6120 i64 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6121</pre>
6122
6123<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6124<p>The '<tt>llvm.memmove.*</tt>' intrinsics move a block of memory from the
6125 source location to the destination location. It is similar to the
6126 '<tt>llvm.memcpy</tt>' intrinsic but allows the two memory locations to
6127 overlap.</p>
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6128
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6129<p>Note that, unlike the standard libc function, the <tt>llvm.memmove.*</tt>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6130 intrinsics do not return a value, takes extra alignment/isvolatile arguments
6131 and the pointers can be in specified address spaces.</p>
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6132
6133<h5>Arguments:</h5>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6134
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6135<p>The first argument is a pointer to the destination, the second is a pointer
6136 to the source. The third argument is an integer argument specifying the
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6137 number of bytes to copy, the fourth argument is the alignment of the
6138 source and destination locations, and the fifth is a boolean indicating a
6139 volatile access.</p>
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6140
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]6141<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]6142 then the caller guarantees that the source and destination pointers are
6143 aligned to that boundary.</p>
Chris Lattner4c67c482004-02-12 21:18:15 +0000[diff] [blame]6144
Jeffrey Yasskin5d284ae2010-04-26 21:21:24 +0000[diff] [blame]6145<p>If the <tt>isvolatile</tt> parameter is <tt>true</tt>, the
6146 <tt>llvm.memmove</tt> call is a <a href="#volatile">volatile operation</a>.
6147 The detailed access behavior is not very cleanly specified and it is unwise
6148 to depend on it.</p>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6149
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6150<h5>Semantics:</h5>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6151
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6152<p>The '<tt>llvm.memmove.*</tt>' intrinsics copy a block of memory from the
6153 source location to the destination location, which may overlap. It copies
6154 "len" bytes of memory over. If the argument is known to be aligned to some
6155 boundary, this can be specified as the fourth argument, otherwise it should
6156 be set to 0 or 1.</p>
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6157
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6158</div>
6159
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6160<!-- _______________________________________________________________________ -->
6161<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6162 <a name="int_memset">'<tt>llvm.memset.*</tt>' Intrinsics</a>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6163</div>
6164
6165<div class="doc_text">
6166
6167<h5>Syntax:</h5>
Chris Lattnerdd708342008-11-21 16:42:48 +0000[diff] [blame]6168<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]6169 width and for different address spaces. However, not all targets support all
6170 bit widths.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6171
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6172<pre>
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]6173 declare void @llvm.memset.p0i8.i32(i8* &lt;dest&gt;, i8 &lt;val&gt;,
Chris Lattner685db9d2010-04-08 00:54:34 +0000[diff] [blame]6174 i32 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]6175 declare void @llvm.memset.p0i8.i64(i8* &lt;dest&gt;, i8 &lt;val&gt;,
Chris Lattner685db9d2010-04-08 00:54:34 +0000[diff] [blame]6176 i64 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6177</pre>
6178
6179<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6180<p>The '<tt>llvm.memset.*</tt>' intrinsics fill a block of memory with a
6181 particular byte value.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6182
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6183<p>Note that, unlike the standard libc function, the <tt>llvm.memset</tt>
John Criswellad05ae42010-07-30 16:30:28 +0000[diff] [blame]6184 intrinsic does not return a value and takes extra alignment/volatile
6185 arguments. Also, the destination can be in an arbitrary address space.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6186
6187<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6188<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]6189 byte value with which to fill it, the third argument is an integer argument
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6190 specifying the number of bytes to fill, and the fourth argument is the known
John Criswellad05ae42010-07-30 16:30:28 +0000[diff] [blame]6191 alignment of the destination location.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6192
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]6193<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]6194 then the caller guarantees that the destination pointer is aligned to that
6195 boundary.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6196
Jeffrey Yasskin5d284ae2010-04-26 21:21:24 +0000[diff] [blame]6197<p>If the <tt>isvolatile</tt> parameter is <tt>true</tt>, the
6198 <tt>llvm.memset</tt> call is a <a href="#volatile">volatile operation</a>.
6199 The detailed access behavior is not very cleanly specified and it is unwise
6200 to depend on it.</p>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6201
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6202<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6203<p>The '<tt>llvm.memset.*</tt>' intrinsics fill "len" bytes of memory starting
6204 at the destination location. If the argument is known to be aligned to some
6205 boundary, this can be specified as the fourth argument, otherwise it should
6206 be set to 0 or 1.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6207
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6208</div>
6209
Chris Lattner3b4f4372004-06-11 02:28:03 +0000[diff] [blame]6210<!-- _______________________________________________________________________ -->
6211<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6212 <a name="int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a>
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]6213</div>
6214
6215<div class="doc_text">
6216
6217<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6218<p>This is an overloaded intrinsic. You can use <tt>llvm.sqrt</tt> on any
6219 floating point or vector of floating point type. Not all targets support all
6220 types however.</p>
6221
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]6222<pre>
Dale Johannesendd89d272007-10-02 17:47:38 +0000[diff] [blame]6223 declare float @llvm.sqrt.f32(float %Val)
6224 declare double @llvm.sqrt.f64(double %Val)
6225 declare x86_fp80 @llvm.sqrt.f80(x86_fp80 %Val)
6226 declare fp128 @llvm.sqrt.f128(fp128 %Val)
6227 declare ppc_fp128 @llvm.sqrt.ppcf128(ppc_fp128 %Val)
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]6228</pre>
6229
6230<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6231<p>The '<tt>llvm.sqrt</tt>' intrinsics return the sqrt of the specified operand,
6232 returning the same value as the libm '<tt>sqrt</tt>' functions would.
6233 Unlike <tt>sqrt</tt> in libm, however, <tt>llvm.sqrt</tt> has undefined
6234 behavior for negative numbers other than -0.0 (which allows for better
6235 optimization, because there is no need to worry about errno being
6236 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]6237
6238<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6239<p>The argument and return value are floating point numbers of the same
6240 type.</p>
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]6241
6242<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6243<p>This function returns the sqrt of the specified operand if it is a
6244 nonnegative floating point number.</p>
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]6245
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]6246</div>
6247
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]6248<!-- _______________________________________________________________________ -->
6249<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6250 <a name="int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a>
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]6251</div>
6252
6253<div class="doc_text">
6254
6255<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6256<p>This is an overloaded intrinsic. You can use <tt>llvm.powi</tt> on any
6257 floating point or vector of floating point type. Not all targets support all
6258 types however.</p>
6259
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]6260<pre>
Dale Johannesendd89d272007-10-02 17:47:38 +0000[diff] [blame]6261 declare float @llvm.powi.f32(float %Val, i32 %power)
6262 declare double @llvm.powi.f64(double %Val, i32 %power)
6263 declare x86_fp80 @llvm.powi.f80(x86_fp80 %Val, i32 %power)
6264 declare fp128 @llvm.powi.f128(fp128 %Val, i32 %power)
6265 declare ppc_fp128 @llvm.powi.ppcf128(ppc_fp128 %Val, i32 %power)
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]6266</pre>
6267
6268<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6269<p>The '<tt>llvm.powi.*</tt>' intrinsics return the first operand raised to the
6270 specified (positive or negative) power. The order of evaluation of
6271 multiplications is not defined. When a vector of floating point type is
6272 used, the second argument remains a scalar integer value.</p>
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]6273
6274<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6275<p>The second argument is an integer power, and the first is a value to raise to
6276 that power.</p>
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]6277
6278<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6279<p>This function returns the first value raised to the second power with an
6280 unspecified sequence of rounding operations.</p>
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]6281
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]6282</div>
6283
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6284<!-- _______________________________________________________________________ -->
6285<div class="doc_subsubsection">
6286 <a name="int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a>
6287</div>
6288
6289<div class="doc_text">
6290
6291<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6292<p>This is an overloaded intrinsic. You can use <tt>llvm.sin</tt> on any
6293 floating point or vector of floating point type. Not all targets support all
6294 types however.</p>
6295
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6296<pre>
6297 declare float @llvm.sin.f32(float %Val)
6298 declare double @llvm.sin.f64(double %Val)
6299 declare x86_fp80 @llvm.sin.f80(x86_fp80 %Val)
6300 declare fp128 @llvm.sin.f128(fp128 %Val)
6301 declare ppc_fp128 @llvm.sin.ppcf128(ppc_fp128 %Val)
6302</pre>
6303
6304<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6305<p>The '<tt>llvm.sin.*</tt>' intrinsics return the sine of the operand.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6306
6307<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6308<p>The argument and return value are floating point numbers of the same
6309 type.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6310
6311<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6312<p>This function returns the sine of the specified operand, returning the same
6313 values as the libm <tt>sin</tt> functions would, and handles error conditions
6314 in the same way.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6315
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6316</div>
6317
6318<!-- _______________________________________________________________________ -->
6319<div class="doc_subsubsection">
6320 <a name="int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a>
6321</div>
6322
6323<div class="doc_text">
6324
6325<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6326<p>This is an overloaded intrinsic. You can use <tt>llvm.cos</tt> on any
6327 floating point or vector of floating point type. Not all targets support all
6328 types however.</p>
6329
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6330<pre>
6331 declare float @llvm.cos.f32(float %Val)
6332 declare double @llvm.cos.f64(double %Val)
6333 declare x86_fp80 @llvm.cos.f80(x86_fp80 %Val)
6334 declare fp128 @llvm.cos.f128(fp128 %Val)
6335 declare ppc_fp128 @llvm.cos.ppcf128(ppc_fp128 %Val)
6336</pre>
6337
6338<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6339<p>The '<tt>llvm.cos.*</tt>' intrinsics return the cosine of the operand.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6340
6341<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6342<p>The argument and return value are floating point numbers of the same
6343 type.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6344
6345<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6346<p>This function returns the cosine of the specified operand, returning the same
6347 values as the libm <tt>cos</tt> functions would, and handles error conditions
6348 in the same way.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6349
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6350</div>
6351
6352<!-- _______________________________________________________________________ -->
6353<div class="doc_subsubsection">
6354 <a name="int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a>
6355</div>
6356
6357<div class="doc_text">
6358
6359<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6360<p>This is an overloaded intrinsic. You can use <tt>llvm.pow</tt> on any
6361 floating point or vector of floating point type. Not all targets support all
6362 types however.</p>
6363
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6364<pre>
6365 declare float @llvm.pow.f32(float %Val, float %Power)
6366 declare double @llvm.pow.f64(double %Val, double %Power)
6367 declare x86_fp80 @llvm.pow.f80(x86_fp80 %Val, x86_fp80 %Power)
6368 declare fp128 @llvm.pow.f128(fp128 %Val, fp128 %Power)
6369 declare ppc_fp128 @llvm.pow.ppcf128(ppc_fp128 %Val, ppc_fp128 Power)
6370</pre>
6371
6372<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6373<p>The '<tt>llvm.pow.*</tt>' intrinsics return the first operand raised to the
6374 specified (positive or negative) power.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6375
6376<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6377<p>The second argument is a floating point power, and the first is a value to
6378 raise to that power.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6379
6380<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6381<p>This function returns the first value raised to the second power, returning
6382 the same values as the libm <tt>pow</tt> functions would, and handles error
6383 conditions in the same way.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6384
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6385</div>
6386
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6387<!-- ======================================================================= -->
6388<div class="doc_subsection">
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]6389 <a name="int_manip">Bit Manipulation Intrinsics</a>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6390</div>
6391
6392<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6393
6394<p>LLVM provides intrinsics for a few important bit manipulation operations.
6395 These allow efficient code generation for some algorithms.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6396
6397</div>
6398
6399<!-- _______________________________________________________________________ -->
6400<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6401 <a name="int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a>
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]6402</div>
6403
6404<div class="doc_text">
6405
6406<h5>Syntax:</h5>
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]6407<p>This is an overloaded intrinsic function. You can use bswap on any integer
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6408 type that is an even number of bytes (i.e. BitWidth % 16 == 0).</p>
6409
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]6410<pre>
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]6411 declare i16 @llvm.bswap.i16(i16 &lt;id&gt;)
6412 declare i32 @llvm.bswap.i32(i32 &lt;id&gt;)
6413 declare i64 @llvm.bswap.i64(i64 &lt;id&gt;)
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]6414</pre>
6415
6416<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6417<p>The '<tt>llvm.bswap</tt>' family of intrinsics is used to byte swap integer
6418 values with an even number of bytes (positive multiple of 16 bits). These
6419 are useful for performing operations on data that is not in the target's
6420 native byte order.</p>
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]6421
6422<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6423<p>The <tt>llvm.bswap.i16</tt> intrinsic returns an i16 value that has the high
6424 and low byte of the input i16 swapped. Similarly,
6425 the <tt>llvm.bswap.i32</tt> intrinsic returns an i32 value that has the four
6426 bytes of the input i32 swapped, so that if the input bytes are numbered 0, 1,
6427 2, 3 then the returned i32 will have its bytes in 3, 2, 1, 0 order.
6428 The <tt>llvm.bswap.i48</tt>, <tt>llvm.bswap.i64</tt> and other intrinsics
6429 extend this concept to additional even-byte lengths (6 bytes, 8 bytes and
6430 more, respectively).</p>
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]6431
6432</div>
6433
6434<!-- _______________________________________________________________________ -->
6435<div class="doc_subsubsection">
Reid Spencerb4f9a6f2006-01-16 21:12:35 +0000[diff] [blame]6436 <a name="int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic</a>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6437</div>
6438
6439<div class="doc_text">
6440
6441<h5>Syntax:</h5>
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]6442<p>This is an overloaded intrinsic. You can use llvm.ctpop on any integer bit
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6443 width. Not all targets support all bit widths however.</p>
6444
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6445<pre>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6446 declare i8 @llvm.ctpop.i8(i8 &lt;src&gt;)
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]6447 declare i16 @llvm.ctpop.i16(i16 &lt;src&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]6448 declare i32 @llvm.ctpop.i32(i32 &lt;src&gt;)
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]6449 declare i64 @llvm.ctpop.i64(i64 &lt;src&gt;)
6450 declare i256 @llvm.ctpop.i256(i256 &lt;src&gt;)
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6451</pre>
6452
6453<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6454<p>The '<tt>llvm.ctpop</tt>' family of intrinsics counts the number of bits set
6455 in a value.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6456
6457<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6458<p>The only argument is the value to be counted. The argument may be of any
6459 integer type. The return type must match the argument type.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6460
6461<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6462<p>The '<tt>llvm.ctpop</tt>' intrinsic counts the 1's in a variable.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6463
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6464</div>
6465
6466<!-- _______________________________________________________________________ -->
6467<div class="doc_subsubsection">
Chris Lattnerb748c672006-01-16 22:34:14 +0000[diff] [blame]6468 <a name="int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic</a>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6469</div>
6470
6471<div class="doc_text">
6472
6473<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6474<p>This is an overloaded intrinsic. You can use <tt>llvm.ctlz</tt> on any
6475 integer bit width. Not all targets support all bit widths however.</p>
6476
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6477<pre>
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]6478 declare i8 @llvm.ctlz.i8 (i8 &lt;src&gt;)
6479 declare i16 @llvm.ctlz.i16(i16 &lt;src&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]6480 declare i32 @llvm.ctlz.i32(i32 &lt;src&gt;)
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]6481 declare i64 @llvm.ctlz.i64(i64 &lt;src&gt;)
6482 declare i256 @llvm.ctlz.i256(i256 &lt;src&gt;)
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6483</pre>
6484
6485<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6486<p>The '<tt>llvm.ctlz</tt>' family of intrinsic functions counts the number of
6487 leading zeros in a variable.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6488
6489<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6490<p>The only argument is the value to be counted. The argument may be of any
6491 integer type. The return type must match the argument type.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6492
6493<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6494<p>The '<tt>llvm.ctlz</tt>' intrinsic counts the leading (most significant)
6495 zeros in a variable. If the src == 0 then the result is the size in bits of
6496 the type of src. For example, <tt>llvm.ctlz(i32 2) = 30</tt>.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6497
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6498</div>
Chris Lattner3b4f4372004-06-11 02:28:03 +0000[diff] [blame]6499
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]6500<!-- _______________________________________________________________________ -->
6501<div class="doc_subsubsection">
Chris Lattnerb748c672006-01-16 22:34:14 +0000[diff] [blame]6502 <a name="int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic</a>
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]6503</div>
6504
6505<div class="doc_text">
6506
6507<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6508<p>This is an overloaded intrinsic. You can use <tt>llvm.cttz</tt> on any
6509 integer bit width. Not all targets support all bit widths however.</p>
6510
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]6511<pre>
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]6512 declare i8 @llvm.cttz.i8 (i8 &lt;src&gt;)
6513 declare i16 @llvm.cttz.i16(i16 &lt;src&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]6514 declare i32 @llvm.cttz.i32(i32 &lt;src&gt;)
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]6515 declare i64 @llvm.cttz.i64(i64 &lt;src&gt;)
6516 declare i256 @llvm.cttz.i256(i256 &lt;src&gt;)
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]6517</pre>
6518
6519<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6520<p>The '<tt>llvm.cttz</tt>' family of intrinsic functions counts the number of
6521 trailing zeros.</p>
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]6522
6523<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6524<p>The only argument is the value to be counted. The argument may be of any
6525 integer type. The return type must match the argument type.</p>
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]6526
6527<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6528<p>The '<tt>llvm.cttz</tt>' intrinsic counts the trailing (least significant)
6529 zeros in a variable. If the src == 0 then the result is the size in bits of
6530 the type of src. For example, <tt>llvm.cttz(2) = 1</tt>.</p>
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]6531
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]6532</div>
6533
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]6534<!-- ======================================================================= -->
6535<div class="doc_subsection">
6536 <a name="int_overflow">Arithmetic with Overflow Intrinsics</a>
6537</div>
6538
6539<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6540
6541<p>LLVM provides intrinsics for some arithmetic with overflow operations.</p>
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]6542
6543</div>
6544
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6545<!-- _______________________________________________________________________ -->
6546<div class="doc_subsubsection">
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]6547 <a name="int_sadd_overflow">'<tt>llvm.sadd.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6548</div>
6549
6550<div class="doc_text">
6551
6552<h5>Syntax:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6553<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]6554 on any integer bit width.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6555
6556<pre>
6557 declare {i16, i1} @llvm.sadd.with.overflow.i16(i16 %a, i16 %b)
6558 declare {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
6559 declare {i64, i1} @llvm.sadd.with.overflow.i64(i64 %a, i64 %b)
6560</pre>
6561
6562<h5>Overview:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6563<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6564 a signed addition of the two arguments, and indicate whether an overflow
6565 occurred during the signed summation.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6566
6567<h5>Arguments:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6568<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]6569 be of integer types of any bit width, but they must have the same bit
6570 width. The second element of the result structure must be of
6571 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6572 undergo signed addition.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6573
6574<h5>Semantics:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6575<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6576 a signed addition of the two variables. They return a structure &mdash; the
6577 first element of which is the signed summation, and the second element of
6578 which is a bit specifying if the signed summation resulted in an
6579 overflow.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6580
6581<h5>Examples:</h5>
6582<pre>
6583 %res = call {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
6584 %sum = extractvalue {i32, i1} %res, 0
6585 %obit = extractvalue {i32, i1} %res, 1
6586 br i1 %obit, label %overflow, label %normal
6587</pre>
6588
6589</div>
6590
6591<!-- _______________________________________________________________________ -->
6592<div class="doc_subsubsection">
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]6593 <a name="int_uadd_overflow">'<tt>llvm.uadd.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6594</div>
6595
6596<div class="doc_text">
6597
6598<h5>Syntax:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6599<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]6600 on any integer bit width.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6601
6602<pre>
6603 declare {i16, i1} @llvm.uadd.with.overflow.i16(i16 %a, i16 %b)
6604 declare {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
6605 declare {i64, i1} @llvm.uadd.with.overflow.i64(i64 %a, i64 %b)
6606</pre>
6607
6608<h5>Overview:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6609<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6610 an unsigned addition of the two arguments, and indicate whether a carry
6611 occurred during the unsigned summation.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6612
6613<h5>Arguments:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6614<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]6615 be of integer types of any bit width, but they must have the same bit
6616 width. The second element of the result structure must be of
6617 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6618 undergo unsigned addition.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6619
6620<h5>Semantics:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6621<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6622 an unsigned addition of the two arguments. They return a structure &mdash;
6623 the first element of which is the sum, and the second element of which is a
6624 bit specifying if the unsigned summation resulted in a carry.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6625
6626<h5>Examples:</h5>
6627<pre>
6628 %res = call {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
6629 %sum = extractvalue {i32, i1} %res, 0
6630 %obit = extractvalue {i32, i1} %res, 1
6631 br i1 %obit, label %carry, label %normal
6632</pre>
6633
6634</div>
6635
6636<!-- _______________________________________________________________________ -->
6637<div class="doc_subsubsection">
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]6638 <a name="int_ssub_overflow">'<tt>llvm.ssub.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6639</div>
6640
6641<div class="doc_text">
6642
6643<h5>Syntax:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6644<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]6645 on any integer bit width.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6646
6647<pre>
6648 declare {i16, i1} @llvm.ssub.with.overflow.i16(i16 %a, i16 %b)
6649 declare {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
6650 declare {i64, i1} @llvm.ssub.with.overflow.i64(i64 %a, i64 %b)
6651</pre>
6652
6653<h5>Overview:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6654<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6655 a signed subtraction of the two arguments, and indicate whether an overflow
6656 occurred during the signed subtraction.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6657
6658<h5>Arguments:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6659<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]6660 be of integer types of any bit width, but they must have the same bit
6661 width. The second element of the result structure must be of
6662 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6663 undergo signed subtraction.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6664
6665<h5>Semantics:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6666<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6667 a signed subtraction of the two arguments. They return a structure &mdash;
6668 the first element of which is the subtraction, and the second element of
6669 which is a bit specifying if the signed subtraction resulted in an
6670 overflow.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6671
6672<h5>Examples:</h5>
6673<pre>
6674 %res = call {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
6675 %sum = extractvalue {i32, i1} %res, 0
6676 %obit = extractvalue {i32, i1} %res, 1
6677 br i1 %obit, label %overflow, label %normal
6678</pre>
6679
6680</div>
6681
6682<!-- _______________________________________________________________________ -->
6683<div class="doc_subsubsection">
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]6684 <a name="int_usub_overflow">'<tt>llvm.usub.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6685</div>
6686
6687<div class="doc_text">
6688
6689<h5>Syntax:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6690<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]6691 on any integer bit width.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6692
6693<pre>
6694 declare {i16, i1} @llvm.usub.with.overflow.i16(i16 %a, i16 %b)
6695 declare {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
6696 declare {i64, i1} @llvm.usub.with.overflow.i64(i64 %a, i64 %b)
6697</pre>
6698
6699<h5>Overview:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6700<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6701 an unsigned subtraction of the two arguments, and indicate whether an
6702 overflow occurred during the unsigned subtraction.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6703
6704<h5>Arguments:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6705<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]6706 be of integer types of any bit width, but they must have the same bit
6707 width. The second element of the result structure must be of
6708 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6709 undergo unsigned subtraction.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6710
6711<h5>Semantics:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6712<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6713 an unsigned subtraction of the two arguments. They return a structure &mdash;
6714 the first element of which is the subtraction, and the second element of
6715 which is a bit specifying if the unsigned subtraction resulted in an
6716 overflow.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6717
6718<h5>Examples:</h5>
6719<pre>
6720 %res = call {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
6721 %sum = extractvalue {i32, i1} %res, 0
6722 %obit = extractvalue {i32, i1} %res, 1
6723 br i1 %obit, label %overflow, label %normal
6724</pre>
6725
6726</div>
6727
6728<!-- _______________________________________________________________________ -->
6729<div class="doc_subsubsection">
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]6730 <a name="int_smul_overflow">'<tt>llvm.smul.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6731</div>
6732
6733<div class="doc_text">
6734
6735<h5>Syntax:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6736<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]6737 on any integer bit width.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6738
6739<pre>
6740 declare {i16, i1} @llvm.smul.with.overflow.i16(i16 %a, i16 %b)
6741 declare {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
6742 declare {i64, i1} @llvm.smul.with.overflow.i64(i64 %a, i64 %b)
6743</pre>
6744
6745<h5>Overview:</h5>
6746
6747<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6748 a signed multiplication of the two arguments, and indicate whether an
6749 overflow occurred during the signed multiplication.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6750
6751<h5>Arguments:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6752<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]6753 be of integer types of any bit width, but they must have the same bit
6754 width. The second element of the result structure must be of
6755 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6756 undergo signed multiplication.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6757
6758<h5>Semantics:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6759<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6760 a signed multiplication of the two arguments. They return a structure &mdash;
6761 the first element of which is the multiplication, and the second element of
6762 which is a bit specifying if the signed multiplication resulted in an
6763 overflow.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6764
6765<h5>Examples:</h5>
6766<pre>
6767 %res = call {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
6768 %sum = extractvalue {i32, i1} %res, 0
6769 %obit = extractvalue {i32, i1} %res, 1
6770 br i1 %obit, label %overflow, label %normal
6771</pre>
6772
Reid Spencer5bf54c82007-04-11 23:23:49 +0000[diff] [blame]6773</div>
6774
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]6775<!-- _______________________________________________________________________ -->
6776<div class="doc_subsubsection">
6777 <a name="int_umul_overflow">'<tt>llvm.umul.with.overflow.*</tt>' Intrinsics</a>
6778</div>
6779
6780<div class="doc_text">
6781
6782<h5>Syntax:</h5>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]6783<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]6784 on any integer bit width.</p>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]6785
6786<pre>
6787 declare {i16, i1} @llvm.umul.with.overflow.i16(i16 %a, i16 %b)
6788 declare {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
6789 declare {i64, i1} @llvm.umul.with.overflow.i64(i64 %a, i64 %b)
6790</pre>
6791
6792<h5>Overview:</h5>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]6793<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6794 a unsigned multiplication of the two arguments, and indicate whether an
6795 overflow occurred during the unsigned multiplication.</p>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]6796
6797<h5>Arguments:</h5>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]6798<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]6799 be of integer types of any bit width, but they must have the same bit
6800 width. The second element of the result structure must be of
6801 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6802 undergo unsigned multiplication.</p>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]6803
6804<h5>Semantics:</h5>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]6805<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6806 an unsigned multiplication of the two arguments. They return a structure
6807 &mdash; the first element of which is the multiplication, and the second
6808 element of which is a bit specifying if the unsigned multiplication resulted
6809 in an overflow.</p>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]6810
6811<h5>Examples:</h5>
6812<pre>
6813 %res = call {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
6814 %sum = extractvalue {i32, i1} %res, 0
6815 %obit = extractvalue {i32, i1} %res, 1
6816 br i1 %obit, label %overflow, label %normal
6817</pre>
6818
6819</div>
6820
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]6821<!-- ======================================================================= -->
6822<div class="doc_subsection">
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]6823 <a name="int_fp16">Half Precision Floating Point Intrinsics</a>
6824</div>
6825
6826<div class="doc_text">
6827
Chris Lattner022a9fb2010-03-15 04:12:21 +0000[diff] [blame]6828<p>Half precision floating point is a storage-only format. This means that it is
6829 a dense encoding (in memory) but does not support computation in the
6830 format.</p>
Chris Lattnerbbd8bd32010-03-14 23:03:31 +0000[diff] [blame]6831
Chris Lattner022a9fb2010-03-15 04:12:21 +0000[diff] [blame]6832<p>This means that code must first load the half-precision floating point
Chris Lattnerbbd8bd32010-03-14 23:03:31 +0000[diff] [blame]6833 value as an i16, then convert it to float with <a
6834 href="#int_convert_from_fp16"><tt>llvm.convert.from.fp16</tt></a>.
6835 Computation can then be performed on the float value (including extending to
Chris Lattner022a9fb2010-03-15 04:12:21 +0000[diff] [blame]6836 double etc). To store the value back to memory, it is first converted to
6837 float if needed, then converted to i16 with
Chris Lattnerbbd8bd32010-03-14 23:03:31 +0000[diff] [blame]6838 <a href="#int_convert_to_fp16"><tt>llvm.convert.to.fp16</tt></a>, then
6839 storing as an i16 value.</p>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]6840</div>
6841
6842<!-- _______________________________________________________________________ -->
6843<div class="doc_subsubsection">
Chris Lattnerbbd8bd32010-03-14 23:03:31 +0000[diff] [blame]6844 <a name="int_convert_to_fp16">'<tt>llvm.convert.to.fp16</tt>' Intrinsic</a>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]6845</div>
6846
6847<div class="doc_text">
6848
6849<h5>Syntax:</h5>
6850<pre>
6851 declare i16 @llvm.convert.to.fp16(f32 %a)
6852</pre>
6853
6854<h5>Overview:</h5>
6855<p>The '<tt>llvm.convert.to.fp16</tt>' intrinsic function performs
6856 a conversion from single precision floating point format to half precision
6857 floating point format.</p>
6858
6859<h5>Arguments:</h5>
6860<p>The intrinsic function contains single argument - the value to be
6861 converted.</p>
6862
6863<h5>Semantics:</h5>
6864<p>The '<tt>llvm.convert.to.fp16</tt>' intrinsic function performs
6865 a conversion from single precision floating point format to half precision
Chris Lattner022a9fb2010-03-15 04:12:21 +0000[diff] [blame]6866 floating point format. The return value is an <tt>i16</tt> which
Chris Lattnerbbd8bd32010-03-14 23:03:31 +0000[diff] [blame]6867 contains the converted number.</p>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]6868
6869<h5>Examples:</h5>
6870<pre>
6871 %res = call i16 @llvm.convert.to.fp16(f32 %a)
6872 store i16 %res, i16* @x, align 2
6873</pre>
6874
6875</div>
6876
6877<!-- _______________________________________________________________________ -->
6878<div class="doc_subsubsection">
Chris Lattnerbbd8bd32010-03-14 23:03:31 +0000[diff] [blame]6879 <a name="int_convert_from_fp16">'<tt>llvm.convert.from.fp16</tt>' Intrinsic</a>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]6880</div>
6881
6882<div class="doc_text">
6883
6884<h5>Syntax:</h5>
6885<pre>
6886 declare f32 @llvm.convert.from.fp16(i16 %a)
6887</pre>
6888
6889<h5>Overview:</h5>
6890<p>The '<tt>llvm.convert.from.fp16</tt>' intrinsic function performs
6891 a conversion from half precision floating point format to single precision
6892 floating point format.</p>
6893
6894<h5>Arguments:</h5>
6895<p>The intrinsic function contains single argument - the value to be
6896 converted.</p>
6897
6898<h5>Semantics:</h5>
6899<p>The '<tt>llvm.convert.from.fp16</tt>' intrinsic function performs a
Chris Lattner022a9fb2010-03-15 04:12:21 +0000[diff] [blame]6900 conversion from half single precision floating point format to single
Chris Lattnerbbd8bd32010-03-14 23:03:31 +0000[diff] [blame]6901 precision floating point format. The input half-float value is represented by
6902 an <tt>i16</tt> value.</p>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]6903
6904<h5>Examples:</h5>
6905<pre>
6906 %a = load i16* @x, align 2
6907 %res = call f32 @llvm.convert.from.fp16(i16 %a)
6908</pre>
6909
6910</div>
6911
6912<!-- ======================================================================= -->
6913<div class="doc_subsection">
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]6914 <a name="int_debugger">Debugger Intrinsics</a>
6915</div>
6916
6917<div class="doc_text">
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]6918
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6919<p>The LLVM debugger intrinsics (which all start with <tt>llvm.dbg.</tt>
6920 prefix), are described in
6921 the <a href="SourceLevelDebugging.html#format_common_intrinsics">LLVM Source
6922 Level Debugging</a> document.</p>
6923
6924</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]6925
Jim Laskey2211f492007-03-14 19:31:19 +0000[diff] [blame]6926<!-- ======================================================================= -->
6927<div class="doc_subsection">
6928 <a name="int_eh">Exception Handling Intrinsics</a>
6929</div>
6930
6931<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6932
6933<p>The LLVM exception handling intrinsics (which all start with
6934 <tt>llvm.eh.</tt> prefix), are described in
6935 the <a href="ExceptionHandling.html#format_common_intrinsics">LLVM Exception
6936 Handling</a> document.</p>
6937
Jim Laskey2211f492007-03-14 19:31:19 +0000[diff] [blame]6938</div>
6939
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]6940<!-- ======================================================================= -->
6941<div class="doc_subsection">
Duncan Sands86e01192007-09-11 14:10:23 +0000[diff] [blame]6942 <a name="int_trampoline">Trampoline Intrinsic</a>
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]6943</div>
6944
6945<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6946
6947<p>This intrinsic makes it possible to excise one parameter, marked with
Dan Gohman3770af52010-07-02 23:18:08 +0000[diff] [blame]6948 the <a href="#nest"><tt>nest</tt></a> attribute, from a function.
6949 The result is a callable
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6950 function pointer lacking the nest parameter - the caller does not need to
6951 provide a value for it. Instead, the value to use is stored in advance in a
6952 "trampoline", a block of memory usually allocated on the stack, which also
6953 contains code to splice the nest value into the argument list. This is used
6954 to implement the GCC nested function address extension.</p>
6955
6956<p>For example, if the function is
6957 <tt>i32 f(i8* nest %c, i32 %x, i32 %y)</tt> then the resulting function
6958 pointer has signature <tt>i32 (i32, i32)*</tt>. It can be created as
6959 follows:</p>
6960
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]6961<pre class="doc_code">
Duncan Sands86e01192007-09-11 14:10:23 +0000[diff] [blame]6962 %tramp = alloca [10 x i8], align 4 ; size and alignment only correct for X86
6963 %tramp1 = getelementptr [10 x i8]* %tramp, i32 0, i32 0
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]6964 %p = call i8* @llvm.init.trampoline(i8* %tramp1, i8* bitcast (i32 (i8* nest , i32, i32)* @f to i8*), i8* %nval)
Duncan Sands86e01192007-09-11 14:10:23 +0000[diff] [blame]6965 %fp = bitcast i8* %p to i32 (i32, i32)*
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]6966</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6967
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]6968<p>The call <tt>%val = call i32 %fp(i32 %x, i32 %y)</tt> is then equivalent
6969 to <tt>%val = call i32 %f(i8* %nval, i32 %x, i32 %y)</tt>.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6970
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]6971</div>
6972
6973<!-- _______________________________________________________________________ -->
6974<div class="doc_subsubsection">
6975 <a name="int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a>
6976</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6977
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]6978<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6979
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]6980<h5>Syntax:</h5>
6981<pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6982 declare i8* @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]6983</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6984
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]6985<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6986<p>This fills the memory pointed to by <tt>tramp</tt> with code and returns a
6987 function pointer suitable for executing it.</p>
6988
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]6989<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6990<p>The <tt>llvm.init.trampoline</tt> intrinsic takes three arguments, all
6991 pointers. The <tt>tramp</tt> argument must point to a sufficiently large and
6992 sufficiently aligned block of memory; this memory is written to by the
6993 intrinsic. Note that the size and the alignment are target-specific - LLVM
6994 currently provides no portable way of determining them, so a front-end that
6995 generates this intrinsic needs to have some target-specific knowledge.
6996 The <tt>func</tt> argument must hold a function bitcast to
6997 an <tt>i8*</tt>.</p>
6998
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]6999<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7000<p>The block of memory pointed to by <tt>tramp</tt> is filled with target
7001 dependent code, turning it into a function. A pointer to this function is
7002 returned, but needs to be bitcast to an <a href="#int_trampoline">appropriate
7003 function pointer type</a> before being called. The new function's signature
7004 is the same as that of <tt>func</tt> with any arguments marked with
7005 the <tt>nest</tt> attribute removed. At most one such <tt>nest</tt> argument
7006 is allowed, and it must be of pointer type. Calling the new function is
7007 equivalent to calling <tt>func</tt> with the same argument list, but
7008 with <tt>nval</tt> used for the missing <tt>nest</tt> argument. If, after
7009 calling <tt>llvm.init.trampoline</tt>, the memory pointed to
7010 by <tt>tramp</tt> is modified, then the effect of any later call to the
7011 returned function pointer is undefined.</p>
7012
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]7013</div>
7014
7015<!-- ======================================================================= -->
7016<div class="doc_subsection">
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7017 <a name="int_atomics">Atomic Operations and Synchronization Intrinsics</a>
7018</div>
7019
7020<div class="doc_text">
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7021
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7022<p>These intrinsic functions expand the "universal IR" of LLVM to represent
7023 hardware constructs for atomic operations and memory synchronization. This
7024 provides an interface to the hardware, not an interface to the programmer. It
7025 is aimed at a low enough level to allow any programming models or APIs
7026 (Application Programming Interfaces) which need atomic behaviors to map
7027 cleanly onto it. It is also modeled primarily on hardware behavior. Just as
7028 hardware provides a "universal IR" for source languages, it also provides a
7029 starting point for developing a "universal" atomic operation and
7030 synchronization IR.</p>
7031
7032<p>These do <em>not</em> form an API such as high-level threading libraries,
7033 software transaction memory systems, atomic primitives, and intrinsic
7034 functions as found in BSD, GNU libc, atomic_ops, APR, and other system and
7035 application libraries. The hardware interface provided by LLVM should allow
7036 a clean implementation of all of these APIs and parallel programming models.
7037 No one model or paradigm should be selected above others unless the hardware
7038 itself ubiquitously does so.</p>
7039
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7040</div>
7041
7042<!-- _______________________________________________________________________ -->
7043<div class="doc_subsubsection">
7044 <a name="int_memory_barrier">'<tt>llvm.memory.barrier</tt>' Intrinsic</a>
7045</div>
7046<div class="doc_text">
7047<h5>Syntax:</h5>
7048<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7049 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]7050</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7051
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7052<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7053<p>The <tt>llvm.memory.barrier</tt> intrinsic guarantees ordering between
7054 specific pairs of memory access types.</p>
7055
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7056<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7057<p>The <tt>llvm.memory.barrier</tt> intrinsic requires five boolean arguments.
7058 The first four arguments enables a specific barrier as listed below. The
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]7059 fifth argument specifies that the barrier applies to io or device or uncached
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7060 memory.</p>
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7061
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7062<ul>
7063 <li><tt>ll</tt>: load-load barrier</li>
7064 <li><tt>ls</tt>: load-store barrier</li>
7065 <li><tt>sl</tt>: store-load barrier</li>
7066 <li><tt>ss</tt>: store-store barrier</li>
7067 <li><tt>device</tt>: barrier applies to device and uncached memory also.</li>
7068</ul>
7069
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7070<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7071<p>This intrinsic causes the system to enforce some ordering constraints upon
7072 the loads and stores of the program. This barrier does not
7073 indicate <em>when</em> any events will occur, it only enforces
7074 an <em>order</em> in which they occur. For any of the specified pairs of load
7075 and store operations (f.ex. load-load, or store-load), all of the first
7076 operations preceding the barrier will complete before any of the second
7077 operations succeeding the barrier begin. Specifically the semantics for each
7078 pairing is as follows:</p>
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7079
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7080<ul>
7081 <li><tt>ll</tt>: All loads before the barrier must complete before any load
7082 after the barrier begins.</li>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]7083 <li><tt>ls</tt>: All loads before the barrier must complete before any
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7084 store after the barrier begins.</li>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]7085 <li><tt>ss</tt>: All stores before the barrier must complete before any
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7086 store after the barrier begins.</li>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]7087 <li><tt>sl</tt>: All stores before the barrier must complete before any
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7088 load after the barrier begins.</li>
7089</ul>
7090
7091<p>These semantics are applied with a logical "and" behavior when more than one
7092 is enabled in a single memory barrier intrinsic.</p>
7093
7094<p>Backends may implement stronger barriers than those requested when they do
7095 not support as fine grained a barrier as requested. Some architectures do
7096 not need all types of barriers and on such architectures, these become
7097 noops.</p>
7098
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7099<h5>Example:</h5>
7100<pre>
Victor Hernandeza70c6df2009-10-26 23:44:29 +0000[diff] [blame]7101%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7102%ptr = bitcast i8* %mallocP to i32*
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7103 store i32 4, %ptr
7104
7105%result1 = load i32* %ptr <i>; yields {i32}:result1 = 4</i>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7106 call void @llvm.memory.barrier(i1 false, i1 true, i1 false, i1 false)
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7107 <i>; guarantee the above finishes</i>
7108 store i32 8, %ptr <i>; before this begins</i>
7109</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7110
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7111</div>
7112
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7113<!-- _______________________________________________________________________ -->
7114<div class="doc_subsubsection">
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7115 <a name="int_atomic_cmp_swap">'<tt>llvm.atomic.cmp.swap.*</tt>' Intrinsic</a>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7116</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7117
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7118<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7119
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7120<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7121<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.cmp.swap</tt> on
7122 any integer bit width and for different address spaces. Not all targets
7123 support all bit widths however.</p>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7124
7125<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7126 declare i8 @llvm.atomic.cmp.swap.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;cmp&gt;, i8 &lt;val&gt;)
7127 declare i16 @llvm.atomic.cmp.swap.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;cmp&gt;, i16 &lt;val&gt;)
7128 declare i32 @llvm.atomic.cmp.swap.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;cmp&gt;, i32 &lt;val&gt;)
7129 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]7130</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7131
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7132<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7133<p>This loads a value in memory and compares it to a given value. If they are
7134 equal, it stores a new value into the memory.</p>
7135
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7136<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7137<p>The <tt>llvm.atomic.cmp.swap</tt> intrinsic takes three arguments. The result
7138 as well as both <tt>cmp</tt> and <tt>val</tt> must be integer values with the
7139 same bit width. The <tt>ptr</tt> argument must be a pointer to a value of
7140 this integer type. While any bit width integer may be used, targets may only
7141 lower representations they support in hardware.</p>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7142
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7143<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7144<p>This entire intrinsic must be executed atomically. It first loads the value
7145 in memory pointed to by <tt>ptr</tt> and compares it with the
7146 value <tt>cmp</tt>. If they are equal, <tt>val</tt> is stored into the
7147 memory. The loaded value is yielded in all cases. This provides the
7148 equivalent of an atomic compare-and-swap operation within the SSA
7149 framework.</p>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7150
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7151<h5>Examples:</h5>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7152<pre>
Victor Hernandeza70c6df2009-10-26 23:44:29 +0000[diff] [blame]7153%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7154%ptr = bitcast i8* %mallocP to i32*
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7155 store i32 4, %ptr
7156
7157%val1 = add i32 4, 4
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7158%result1 = call i32 @llvm.atomic.cmp.swap.i32.p0i32(i32* %ptr, i32 4, %val1)
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7159 <i>; yields {i32}:result1 = 4</i>
7160%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
7161%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
7162
7163%val2 = add i32 1, 1
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7164%result2 = call i32 @llvm.atomic.cmp.swap.i32.p0i32(i32* %ptr, i32 5, %val2)
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7165 <i>; yields {i32}:result2 = 8</i>
7166%stored2 = icmp eq i32 %result2, 5 <i>; yields {i1}:stored2 = false</i>
7167
7168%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 8</i>
7169</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7170
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7171</div>
7172
7173<!-- _______________________________________________________________________ -->
7174<div class="doc_subsubsection">
7175 <a name="int_atomic_swap">'<tt>llvm.atomic.swap.*</tt>' Intrinsic</a>
7176</div>
7177<div class="doc_text">
7178<h5>Syntax:</h5>
7179
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7180<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.swap</tt> on any
7181 integer bit width. Not all targets support all bit widths however.</p>
7182
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7183<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7184 declare i8 @llvm.atomic.swap.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;val&gt;)
7185 declare i16 @llvm.atomic.swap.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;val&gt;)
7186 declare i32 @llvm.atomic.swap.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;val&gt;)
7187 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]7188</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7189
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7190<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7191<p>This intrinsic loads the value stored in memory at <tt>ptr</tt> and yields
7192 the value from memory. It then stores the value in <tt>val</tt> in the memory
7193 at <tt>ptr</tt>.</p>
7194
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7195<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7196<p>The <tt>llvm.atomic.swap</tt> intrinsic takes two arguments. Both
7197 the <tt>val</tt> argument and the result must be integers of the same bit
7198 width. The first argument, <tt>ptr</tt>, must be a pointer to a value of this
7199 integer type. The targets may only lower integer representations they
7200 support.</p>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7201
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7202<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7203<p>This intrinsic loads the value pointed to by <tt>ptr</tt>, yields it, and
7204 stores <tt>val</tt> back into <tt>ptr</tt> atomically. This provides the
7205 equivalent of an atomic swap operation within the SSA framework.</p>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7206
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7207<h5>Examples:</h5>
7208<pre>
Victor Hernandeza70c6df2009-10-26 23:44:29 +0000[diff] [blame]7209%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7210%ptr = bitcast i8* %mallocP to i32*
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7211 store i32 4, %ptr
7212
7213%val1 = add i32 4, 4
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7214%result1 = call i32 @llvm.atomic.swap.i32.p0i32(i32* %ptr, i32 %val1)
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7215 <i>; yields {i32}:result1 = 4</i>
7216%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
7217%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
7218
7219%val2 = add i32 1, 1
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7220%result2 = call i32 @llvm.atomic.swap.i32.p0i32(i32* %ptr, i32 %val2)
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7221 <i>; yields {i32}:result2 = 8</i>
7222
7223%stored2 = icmp eq i32 %result2, 8 <i>; yields {i1}:stored2 = true</i>
7224%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 2</i>
7225</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7226
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7227</div>
7228
7229<!-- _______________________________________________________________________ -->
7230<div class="doc_subsubsection">
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7231 <a name="int_atomic_load_add">'<tt>llvm.atomic.load.add.*</tt>' Intrinsic</a>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7232
7233</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7234
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7235<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7236
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7237<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7238<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.load.add</tt> on
7239 any integer bit width. Not all targets support all bit widths however.</p>
7240
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7241<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7242 declare i8 @llvm.atomic.load.add.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7243 declare i16 @llvm.atomic.load.add.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7244 declare i32 @llvm.atomic.load.add.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7245 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]7246</pre>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7247
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7248<h5>Overview:</h5>
7249<p>This intrinsic adds <tt>delta</tt> to the value stored in memory
7250 at <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.</p>
7251
7252<h5>Arguments:</h5>
7253<p>The intrinsic takes two arguments, the first a pointer to an integer value
7254 and the second an integer value. The result is also an integer value. These
7255 integer types can have any bit width, but they must all have the same bit
7256 width. The targets may only lower integer representations they support.</p>
7257
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7258<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7259<p>This intrinsic does a series of operations atomically. It first loads the
7260 value stored at <tt>ptr</tt>. It then adds <tt>delta</tt>, stores the result
7261 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]7262
7263<h5>Examples:</h5>
7264<pre>
Victor Hernandeza70c6df2009-10-26 23:44:29 +0000[diff] [blame]7265%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7266%ptr = bitcast i8* %mallocP to i32*
7267 store i32 4, %ptr
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7268%result1 = call i32 @llvm.atomic.load.add.i32.p0i32(i32* %ptr, i32 4)
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7269 <i>; yields {i32}:result1 = 4</i>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7270%result2 = call i32 @llvm.atomic.load.add.i32.p0i32(i32* %ptr, i32 2)
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7271 <i>; yields {i32}:result2 = 8</i>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7272%result3 = call i32 @llvm.atomic.load.add.i32.p0i32(i32* %ptr, i32 5)
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7273 <i>; yields {i32}:result3 = 10</i>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7274%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 15</i>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7275</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7276
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7277</div>
7278
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7279<!-- _______________________________________________________________________ -->
7280<div class="doc_subsubsection">
7281 <a name="int_atomic_load_sub">'<tt>llvm.atomic.load.sub.*</tt>' Intrinsic</a>
7282
7283</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7284
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7285<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7286
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7287<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7288<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.load.sub</tt> on
7289 any integer bit width and for different address spaces. Not all targets
7290 support all bit widths however.</p>
7291
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7292<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7293 declare i8 @llvm.atomic.load.sub.i8.p0i32(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7294 declare i16 @llvm.atomic.load.sub.i16.p0i32(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7295 declare i32 @llvm.atomic.load.sub.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7296 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]7297</pre>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7298
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7299<h5>Overview:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]7300<p>This intrinsic subtracts <tt>delta</tt> to the value stored in memory at
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7301 <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.</p>
7302
7303<h5>Arguments:</h5>
7304<p>The intrinsic takes two arguments, the first a pointer to an integer value
7305 and the second an integer value. The result is also an integer value. These
7306 integer types can have any bit width, but they must all have the same bit
7307 width. The targets may only lower integer representations they support.</p>
7308
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7309<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7310<p>This intrinsic does a series of operations atomically. It first loads the
7311 value stored at <tt>ptr</tt>. It then subtracts <tt>delta</tt>, stores the
7312 result to <tt>ptr</tt>. It yields the original value stored
7313 at <tt>ptr</tt>.</p>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7314
7315<h5>Examples:</h5>
7316<pre>
Victor Hernandeza70c6df2009-10-26 23:44:29 +0000[diff] [blame]7317%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7318%ptr = bitcast i8* %mallocP to i32*
7319 store i32 8, %ptr
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7320%result1 = call i32 @llvm.atomic.load.sub.i32.p0i32(i32* %ptr, i32 4)
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7321 <i>; yields {i32}:result1 = 8</i>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7322%result2 = call i32 @llvm.atomic.load.sub.i32.p0i32(i32* %ptr, i32 2)
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7323 <i>; yields {i32}:result2 = 4</i>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7324%result3 = call i32 @llvm.atomic.load.sub.i32.p0i32(i32* %ptr, i32 5)
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7325 <i>; yields {i32}:result3 = 2</i>
7326%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = -3</i>
7327</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7328
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7329</div>
7330
7331<!-- _______________________________________________________________________ -->
7332<div class="doc_subsubsection">
7333 <a name="int_atomic_load_and">'<tt>llvm.atomic.load.and.*</tt>' Intrinsic</a><br>
7334 <a name="int_atomic_load_nand">'<tt>llvm.atomic.load.nand.*</tt>' Intrinsic</a><br>
7335 <a name="int_atomic_load_or">'<tt>llvm.atomic.load.or.*</tt>' Intrinsic</a><br>
7336 <a name="int_atomic_load_xor">'<tt>llvm.atomic.load.xor.*</tt>' Intrinsic</a><br>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7337</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7338
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7339<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7340
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7341<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7342<p>These are overloaded intrinsics. You can
7343 use <tt>llvm.atomic.load_and</tt>, <tt>llvm.atomic.load_nand</tt>,
7344 <tt>llvm.atomic.load_or</tt>, and <tt>llvm.atomic.load_xor</tt> on any integer
7345 bit width and for different address spaces. Not all targets support all bit
7346 widths however.</p>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7347
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7348<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7349 declare i8 @llvm.atomic.load.and.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7350 declare i16 @llvm.atomic.load.and.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7351 declare i32 @llvm.atomic.load.and.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7352 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]7353</pre>
7354
7355<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7356 declare i8 @llvm.atomic.load.or.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7357 declare i16 @llvm.atomic.load.or.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7358 declare i32 @llvm.atomic.load.or.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7359 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]7360</pre>
7361
7362<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7363 declare i8 @llvm.atomic.load.nand.i8.p0i32(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7364 declare i16 @llvm.atomic.load.nand.i16.p0i32(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7365 declare i32 @llvm.atomic.load.nand.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7366 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]7367</pre>
7368
7369<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7370 declare i8 @llvm.atomic.load.xor.i8.p0i32(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7371 declare i16 @llvm.atomic.load.xor.i16.p0i32(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7372 declare i32 @llvm.atomic.load.xor.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7373 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]7374</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7375
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7376<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7377<p>These intrinsics bitwise the operation (and, nand, or, xor) <tt>delta</tt> to
7378 the value stored in memory at <tt>ptr</tt>. It yields the original value
7379 at <tt>ptr</tt>.</p>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7380
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7381<h5>Arguments:</h5>
7382<p>These intrinsics take two arguments, the first a pointer to an integer value
7383 and the second an integer value. The result is also an integer value. These
7384 integer types can have any bit width, but they must all have the same bit
7385 width. The targets may only lower integer representations they support.</p>
7386
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7387<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7388<p>These intrinsics does a series of operations atomically. They first load the
7389 value stored at <tt>ptr</tt>. They then do the bitwise
7390 operation <tt>delta</tt>, store the result to <tt>ptr</tt>. They yield the
7391 original value stored at <tt>ptr</tt>.</p>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7392
7393<h5>Examples:</h5>
7394<pre>
Victor Hernandeza70c6df2009-10-26 23:44:29 +0000[diff] [blame]7395%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7396%ptr = bitcast i8* %mallocP to i32*
7397 store i32 0x0F0F, %ptr
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7398%result0 = call i32 @llvm.atomic.load.nand.i32.p0i32(i32* %ptr, i32 0xFF)
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7399 <i>; yields {i32}:result0 = 0x0F0F</i>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7400%result1 = call i32 @llvm.atomic.load.and.i32.p0i32(i32* %ptr, i32 0xFF)
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7401 <i>; yields {i32}:result1 = 0xFFFFFFF0</i>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7402%result2 = call i32 @llvm.atomic.load.or.i32.p0i32(i32* %ptr, i32 0F)
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7403 <i>; yields {i32}:result2 = 0xF0</i>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7404%result3 = call i32 @llvm.atomic.load.xor.i32.p0i32(i32* %ptr, i32 0F)
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7405 <i>; yields {i32}:result3 = FF</i>
7406%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = F0</i>
7407</pre>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7408
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7409</div>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7410
7411<!-- _______________________________________________________________________ -->
7412<div class="doc_subsubsection">
7413 <a name="int_atomic_load_max">'<tt>llvm.atomic.load.max.*</tt>' Intrinsic</a><br>
7414 <a name="int_atomic_load_min">'<tt>llvm.atomic.load.min.*</tt>' Intrinsic</a><br>
7415 <a name="int_atomic_load_umax">'<tt>llvm.atomic.load.umax.*</tt>' Intrinsic</a><br>
7416 <a name="int_atomic_load_umin">'<tt>llvm.atomic.load.umin.*</tt>' Intrinsic</a><br>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7417</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7418
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7419<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7420
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7421<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7422<p>These are overloaded intrinsics. You can use <tt>llvm.atomic.load_max</tt>,
7423 <tt>llvm.atomic.load_min</tt>, <tt>llvm.atomic.load_umax</tt>, and
7424 <tt>llvm.atomic.load_umin</tt> on any integer bit width and for different
7425 address spaces. Not all targets support all bit widths however.</p>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7426
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7427<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7428 declare i8 @llvm.atomic.load.max.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7429 declare i16 @llvm.atomic.load.max.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7430 declare i32 @llvm.atomic.load.max.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7431 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]7432</pre>
7433
7434<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7435 declare i8 @llvm.atomic.load.min.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7436 declare i16 @llvm.atomic.load.min.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7437 declare i32 @llvm.atomic.load.min.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7438 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]7439</pre>
7440
7441<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7442 declare i8 @llvm.atomic.load.umax.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7443 declare i16 @llvm.atomic.load.umax.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7444 declare i32 @llvm.atomic.load.umax.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7445 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]7446</pre>
7447
7448<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7449 declare i8 @llvm.atomic.load.umin.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7450 declare i16 @llvm.atomic.load.umin.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7451 declare i32 @llvm.atomic.load.umin.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7452 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]7453</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7454
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7455<h5>Overview:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]7456<p>These intrinsics takes the signed or unsigned minimum or maximum of
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7457 <tt>delta</tt> and the value stored in memory at <tt>ptr</tt>. It yields the
7458 original value at <tt>ptr</tt>.</p>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7459
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7460<h5>Arguments:</h5>
7461<p>These intrinsics take two arguments, the first a pointer to an integer value
7462 and the second an integer value. The result is also an integer value. These
7463 integer types can have any bit width, but they must all have the same bit
7464 width. The targets may only lower integer representations they support.</p>
7465
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7466<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7467<p>These intrinsics does a series of operations atomically. They first load the
7468 value stored at <tt>ptr</tt>. They then do the signed or unsigned min or
7469 max <tt>delta</tt> and the value, store the result to <tt>ptr</tt>. They
7470 yield the original value stored at <tt>ptr</tt>.</p>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7471
7472<h5>Examples:</h5>
7473<pre>
Victor Hernandeza70c6df2009-10-26 23:44:29 +0000[diff] [blame]7474%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7475%ptr = bitcast i8* %mallocP to i32*
7476 store i32 7, %ptr
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7477%result0 = call i32 @llvm.atomic.load.min.i32.p0i32(i32* %ptr, i32 -2)
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7478 <i>; yields {i32}:result0 = 7</i>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7479%result1 = call i32 @llvm.atomic.load.max.i32.p0i32(i32* %ptr, i32 8)
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7480 <i>; yields {i32}:result1 = -2</i>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7481%result2 = call i32 @llvm.atomic.load.umin.i32.p0i32(i32* %ptr, i32 10)
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7482 <i>; yields {i32}:result2 = 8</i>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7483%result3 = call i32 @llvm.atomic.load.umax.i32.p0i32(i32* %ptr, i32 30)
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7484 <i>; yields {i32}:result3 = 8</i>
7485%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 30</i>
7486</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7487
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7488</div>
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7489
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]7490
7491<!-- ======================================================================= -->
7492<div class="doc_subsection">
7493 <a name="int_memorymarkers">Memory Use Markers</a>
7494</div>
7495
7496<div class="doc_text">
7497
7498<p>This class of intrinsics exists to information about the lifetime of memory
7499 objects and ranges where variables are immutable.</p>
7500
7501</div>
7502
7503<!-- _______________________________________________________________________ -->
7504<div class="doc_subsubsection">
7505 <a name="int_lifetime_start">'<tt>llvm.lifetime.start</tt>' Intrinsic</a>
7506</div>
7507
7508<div class="doc_text">
7509
7510<h5>Syntax:</h5>
7511<pre>
7512 declare void @llvm.lifetime.start(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7513</pre>
7514
7515<h5>Overview:</h5>
7516<p>The '<tt>llvm.lifetime.start</tt>' intrinsic specifies the start of a memory
7517 object's lifetime.</p>
7518
7519<h5>Arguments:</h5>
Nick Lewycky9bc89042009-10-13 07:57:33 +0000[diff] [blame]7520<p>The first argument is a constant integer representing the size of the
7521 object, or -1 if it is variable sized. The second argument is a pointer to
7522 the object.</p>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]7523
7524<h5>Semantics:</h5>
7525<p>This intrinsic indicates that before this point in the code, the value of the
7526 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]7527 never be used and has an undefined value. A load from the pointer that
7528 precedes this intrinsic can be replaced with
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]7529 <tt>'<a href="#undefvalues">undef</a>'</tt>.</p>
7530
7531</div>
7532
7533<!-- _______________________________________________________________________ -->
7534<div class="doc_subsubsection">
7535 <a name="int_lifetime_end">'<tt>llvm.lifetime.end</tt>' Intrinsic</a>
7536</div>
7537
7538<div class="doc_text">
7539
7540<h5>Syntax:</h5>
7541<pre>
7542 declare void @llvm.lifetime.end(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7543</pre>
7544
7545<h5>Overview:</h5>
7546<p>The '<tt>llvm.lifetime.end</tt>' intrinsic specifies the end of a memory
7547 object's lifetime.</p>
7548
7549<h5>Arguments:</h5>
Nick Lewycky9bc89042009-10-13 07:57:33 +0000[diff] [blame]7550<p>The first argument is a constant integer representing the size of the
7551 object, or -1 if it is variable sized. The second argument is a pointer to
7552 the object.</p>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]7553
7554<h5>Semantics:</h5>
7555<p>This intrinsic indicates that after this point in the code, the value of the
7556 memory pointed to by <tt>ptr</tt> is dead. This means that it is known to
7557 never be used and has an undefined value. Any stores into the memory object
7558 following this intrinsic may be removed as dead.
7559
7560</div>
7561
7562<!-- _______________________________________________________________________ -->
7563<div class="doc_subsubsection">
7564 <a name="int_invariant_start">'<tt>llvm.invariant.start</tt>' Intrinsic</a>
7565</div>
7566
7567<div class="doc_text">
7568
7569<h5>Syntax:</h5>
7570<pre>
Nick Lewycky2965d3e2010-11-30 04:13:41 +0000[diff] [blame]7571 declare {}* @llvm.invariant.start(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]7572</pre>
7573
7574<h5>Overview:</h5>
7575<p>The '<tt>llvm.invariant.start</tt>' intrinsic specifies that the contents of
7576 a memory object will not change.</p>
7577
7578<h5>Arguments:</h5>
Nick Lewycky9bc89042009-10-13 07:57:33 +0000[diff] [blame]7579<p>The first argument is a constant integer representing the size of the
7580 object, or -1 if it is variable sized. The second argument is a pointer to
7581 the object.</p>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]7582
7583<h5>Semantics:</h5>
7584<p>This intrinsic indicates that until an <tt>llvm.invariant.end</tt> that uses
7585 the return value, the referenced memory location is constant and
7586 unchanging.</p>
7587
7588</div>
7589
7590<!-- _______________________________________________________________________ -->
7591<div class="doc_subsubsection">
7592 <a name="int_invariant_end">'<tt>llvm.invariant.end</tt>' Intrinsic</a>
7593</div>
7594
7595<div class="doc_text">
7596
7597<h5>Syntax:</h5>
7598<pre>
7599 declare void @llvm.invariant.end({}* &lt;start&gt;, i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7600</pre>
7601
7602<h5>Overview:</h5>
7603<p>The '<tt>llvm.invariant.end</tt>' intrinsic specifies that the contents of
7604 a memory object are mutable.</p>
7605
7606<h5>Arguments:</h5>
7607<p>The first argument is the matching <tt>llvm.invariant.start</tt> intrinsic.
Nick Lewycky9bc89042009-10-13 07:57:33 +0000[diff] [blame]7608 The second argument is a constant integer representing the size of the
7609 object, or -1 if it is variable sized and the third argument is a pointer
7610 to the object.</p>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]7611
7612<h5>Semantics:</h5>
7613<p>This intrinsic indicates that the memory is mutable again.</p>
7614
7615</div>
7616
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7617<!-- ======================================================================= -->
7618<div class="doc_subsection">
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]7619 <a name="int_general">General Intrinsics</a>
7620</div>
7621
7622<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7623
7624<p>This class of intrinsics is designed to be generic and has no specific
7625 purpose.</p>
7626
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]7627</div>
7628
7629<!-- _______________________________________________________________________ -->
7630<div class="doc_subsubsection">
7631 <a name="int_var_annotation">'<tt>llvm.var.annotation</tt>' Intrinsic</a>
7632</div>
7633
7634<div class="doc_text">
7635
7636<h5>Syntax:</h5>
7637<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7638 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]7639</pre>
7640
7641<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7642<p>The '<tt>llvm.var.annotation</tt>' intrinsic.</p>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]7643
7644<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7645<p>The first argument is a pointer to a value, the second is a pointer to a
7646 global string, the third is a pointer to a global string which is the source
7647 file name, and the last argument is the line number.</p>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]7648
7649<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7650<p>This intrinsic allows annotation of local variables with arbitrary strings.
7651 This can be useful for special purpose optimizations that want to look for
7652 these annotations. These have no other defined use, they are ignored by code
7653 generation and optimization.</p>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]7654
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]7655</div>
7656
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]7657<!-- _______________________________________________________________________ -->
7658<div class="doc_subsubsection">
Tanya Lattner0186a652007-09-21 23:57:59 +0000[diff] [blame]7659 <a name="int_annotation">'<tt>llvm.annotation.*</tt>' Intrinsic</a>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]7660</div>
7661
7662<div class="doc_text">
7663
7664<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7665<p>This is an overloaded intrinsic. You can use '<tt>llvm.annotation</tt>' on
7666 any integer bit width.</p>
7667
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]7668<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7669 declare i8 @llvm.annotation.i8(i8 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
7670 declare i16 @llvm.annotation.i16(i16 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
7671 declare i32 @llvm.annotation.i32(i32 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
7672 declare i64 @llvm.annotation.i64(i64 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
7673 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]7674</pre>
7675
7676<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7677<p>The '<tt>llvm.annotation</tt>' intrinsic.</p>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]7678
7679<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7680<p>The first argument is an integer value (result of some expression), the
7681 second is a pointer to a global string, the third is a pointer to a global
7682 string which is the source file name, and the last argument is the line
7683 number. It returns the value of the first argument.</p>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]7684
7685<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7686<p>This intrinsic allows annotations to be put on arbitrary expressions with
7687 arbitrary strings. This can be useful for special purpose optimizations that
7688 want to look for these annotations. These have no other defined use, they
7689 are ignored by code generation and optimization.</p>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]7690
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]7691</div>
Jim Laskey2211f492007-03-14 19:31:19 +0000[diff] [blame]7692
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]7693<!-- _______________________________________________________________________ -->
7694<div class="doc_subsubsection">
7695 <a name="int_trap">'<tt>llvm.trap</tt>' Intrinsic</a>
7696</div>
7697
7698<div class="doc_text">
7699
7700<h5>Syntax:</h5>
7701<pre>
7702 declare void @llvm.trap()
7703</pre>
7704
7705<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7706<p>The '<tt>llvm.trap</tt>' intrinsic.</p>
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]7707
7708<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7709<p>None.</p>
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]7710
7711<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7712<p>This intrinsics is lowered to the target dependent trap instruction. If the
7713 target does not have a trap instruction, this intrinsic will be lowered to
7714 the call of the <tt>abort()</tt> function.</p>
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]7715
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]7716</div>
7717
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]7718<!-- _______________________________________________________________________ -->
7719<div class="doc_subsubsection">
Misha Brukman50de2b22008-11-22 23:55:29 +0000[diff] [blame]7720 <a name="int_stackprotector">'<tt>llvm.stackprotector</tt>' Intrinsic</a>
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]7721</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7722
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]7723<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7724
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]7725<h5>Syntax:</h5>
7726<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7727 declare void @llvm.stackprotector(i8* &lt;guard&gt;, i8** &lt;slot&gt;)
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]7728</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7729
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]7730<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7731<p>The <tt>llvm.stackprotector</tt> intrinsic takes the <tt>guard</tt> and
7732 stores it onto the stack at <tt>slot</tt>. The stack slot is adjusted to
7733 ensure that it is placed on the stack before local variables.</p>
7734
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]7735<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7736<p>The <tt>llvm.stackprotector</tt> intrinsic requires two pointer
7737 arguments. The first argument is the value loaded from the stack
7738 guard <tt>@__stack_chk_guard</tt>. The second variable is an <tt>alloca</tt>
7739 that has enough space to hold the value of the guard.</p>
7740
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]7741<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7742<p>This intrinsic causes the prologue/epilogue inserter to force the position of
7743 the <tt>AllocaInst</tt> stack slot to be before local variables on the
7744 stack. This is to ensure that if a local variable on the stack is
7745 overwritten, it will destroy the value of the guard. When the function exits,
Bill Wendling6bbe0912010-10-27 01:07:41 +0000[diff] [blame]7746 the guard on the stack is checked against the original guard. If they are
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7747 different, then the program aborts by calling the <tt>__stack_chk_fail()</tt>
7748 function.</p>
7749
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]7750</div>
7751
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]7752<!-- _______________________________________________________________________ -->
7753<div class="doc_subsubsection">
7754 <a name="int_objectsize">'<tt>llvm.objectsize</tt>' Intrinsic</a>
7755</div>
7756
7757<div class="doc_text">
7758
7759<h5>Syntax:</h5>
7760<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7761 declare i32 @llvm.objectsize.i32(i8* &lt;object&gt;, i1 &lt;type&gt;)
7762 declare i64 @llvm.objectsize.i64(i8* &lt;object&gt;, i1 &lt;type&gt;)
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]7763</pre>
7764
7765<h5>Overview:</h5>
Bill Wendling6bbe0912010-10-27 01:07:41 +0000[diff] [blame]7766<p>The <tt>llvm.objectsize</tt> intrinsic is designed to provide information to
7767 the optimizers to determine at compile time whether a) an operation (like
7768 memcpy) will overflow a buffer that corresponds to an object, or b) that a
7769 runtime check for overflow isn't necessary. An object in this context means
7770 an allocation of a specific class, structure, array, or other object.</p>
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]7771
7772<h5>Arguments:</h5>
Bill Wendling6bbe0912010-10-27 01:07:41 +0000[diff] [blame]7773<p>The <tt>llvm.objectsize</tt> intrinsic takes two arguments. The first
Eric Christopher31e39bd2009-12-23 00:29:49 +0000[diff] [blame]7774 argument is a pointer to or into the <tt>object</tt>. The second argument
Bill Wendling6bbe0912010-10-27 01:07:41 +0000[diff] [blame]7775 is a boolean 0 or 1. This argument determines whether you want the
7776 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]7777 1, variables are not allowed.</p>
7778
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]7779<h5>Semantics:</h5>
7780<p>The <tt>llvm.objectsize</tt> intrinsic is lowered to either a constant
Bill Wendling6bbe0912010-10-27 01:07:41 +0000[diff] [blame]7781 representing the size of the object concerned, or <tt>i32/i64 -1 or 0</tt>,
7782 depending on the <tt>type</tt> argument, if the size cannot be determined at
7783 compile time.</p>
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]7784
7785</div>
7786
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]7787<!-- *********************************************************************** -->
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]7788<hr>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]7789<address>
7790 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
Misha Brukman86242e12008-12-11 17:34:48 +0000[diff] [blame]7791 src="http://jigsaw.w3.org/css-validator/images/vcss-blue" alt="Valid CSS"></a>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]7792 <a href="http://validator.w3.org/check/referer"><img
Misha Brukman86242e12008-12-11 17:34:48 +0000[diff] [blame]7793 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]7794
7795 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
NAKAMURA Takumica46f5a2011-04-09 02:13:37 +0000[diff] [blame^]7796 <a href="http://llvm.org/">The LLVM Compiler Infrastructure</a><br>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]7797 Last modified: $Date$
7798</address>
Chris Lattnerb8f816e2008-01-04 04:33:49 +0000[diff] [blame]7799
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]7800</body>
7801</html>