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gerrit-public.fairphone.software / toolchain / llvm-project / 578ee4070c00a87df183360072d299976d7712a2 / . / llvm / docs / LangRef.html
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4<head>
5 <title>LLVM Assembly Language Reference Manual</title>
Reid Spencercb84e432004-08-26 20:44:00 +0000[diff] [blame]6 <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
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>
65 <li><a href="#t_void">Void Type</a></li>
66 <li><a href="#t_label">Label Type</a></li>
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]67 <li><a href="#t_metadata">Metadata Type</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]68 </ol>
69 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]70 <li><a href="#t_derived">Derived Types</a>
71 <ol>
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]72 <li><a href="#t_aggregate">Aggregate Types</a>
73 <ol>
74 <li><a href="#t_array">Array Type</a></li>
75 <li><a href="#t_struct">Structure Type</a></li>
76 <li><a href="#t_pstruct">Packed Structure Type</a></li>
77 <li><a href="#t_union">Union Type</a></li>
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;
496<a href="#identifiers">@.LC0</a> = <a href="#linkage_internal">internal</a> <a href="#globalvars">constant</a> <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
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]849<p>A global variable may be declared to reside in a target-specific numbered
850 address space. For targets that support them, address spaces may affect how
851 optimizations are performed and/or what target instructions are used to
852 access the variable. The default address space is zero. The address space
853 qualifier must precede any other attributes.</p>
Christopher Lamb308121c2007-12-11 09:31:00 +0000[diff] [blame]854
Chris Lattner662c8722005-11-12 00:45:07 +0000[diff] [blame]855<p>LLVM allows an explicit section to be specified for globals. If the target
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]856 supports it, it will emit globals to the section specified.</p>
Chris Lattner662c8722005-11-12 00:45:07 +0000[diff] [blame]857
Chris Lattner78e00bc2010-04-28 00:13:42 +0000[diff] [blame]858<p>An explicit alignment may be specified for a global, which must be a power
859 of 2. If not present, or if the alignment is set to zero, the alignment of
860 the global is set by the target to whatever it feels convenient. If an
861 explicit alignment is specified, the global is forced to have exactly that
Chris Lattner4bd85e42010-04-28 00:31:12 +0000[diff] [blame]862 alignment. Targets and optimizers are not allowed to over-align the global
863 if the global has an assigned section. In this case, the extra alignment
864 could be observable: for example, code could assume that the globals are
865 densely packed in their section and try to iterate over them as an array,
866 alignment padding would break this iteration.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]867
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]868<p>For example, the following defines a global in a numbered address space with
869 an initializer, section, and alignment:</p>
Chris Lattner5760c502007-01-14 00:27:09 +0000[diff] [blame]870
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]871<pre class="doc_code">
Dan Gohmanaaa679b2009-01-11 00:40:00 +0000[diff] [blame]872@G = addrspace(5) constant float 1.0, section "foo", align 4
Chris Lattner5760c502007-01-14 00:27:09 +0000[diff] [blame]873</pre>
874
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]875</div>
876
877
878<!-- ======================================================================= -->
879<div class="doc_subsection">
880 <a name="functionstructure">Functions</a>
881</div>
882
883<div class="doc_text">
884
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]885<p>LLVM function definitions consist of the "<tt>define</tt>" keyword, an
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]886 optional <a href="#linkage">linkage type</a>, an optional
887 <a href="#visibility">visibility style</a>, an optional
888 <a href="#callingconv">calling convention</a>, a return type, an optional
889 <a href="#paramattrs">parameter attribute</a> for the return type, a function
890 name, a (possibly empty) argument list (each with optional
891 <a href="#paramattrs">parameter attributes</a>), optional
892 <a href="#fnattrs">function attributes</a>, an optional section, an optional
893 alignment, an optional <a href="#gc">garbage collector name</a>, an opening
894 curly brace, a list of basic blocks, and a closing curly brace.</p>
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]895
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]896<p>LLVM function declarations consist of the "<tt>declare</tt>" keyword, an
897 optional <a href="#linkage">linkage type</a>, an optional
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]898 <a href="#visibility">visibility style</a>, an optional
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]899 <a href="#callingconv">calling convention</a>, a return type, an optional
900 <a href="#paramattrs">parameter attribute</a> for the return type, a function
901 name, a possibly empty list of arguments, an optional alignment, and an
902 optional <a href="#gc">garbage collector name</a>.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]903
Chris Lattner67c37d12008-08-05 18:29:16 +0000[diff] [blame]904<p>A function definition contains a list of basic blocks, forming the CFG
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]905 (Control Flow Graph) for the function. Each basic block may optionally start
906 with a label (giving the basic block a symbol table entry), contains a list
907 of instructions, and ends with a <a href="#terminators">terminator</a>
908 instruction (such as a branch or function return).</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]909
Chris Lattnera59fb102007-06-08 16:52:14 +0000[diff] [blame]910<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]911 executed on entrance to the function, and it is not allowed to have
912 predecessor basic blocks (i.e. there can not be any branches to the entry
913 block of a function). Because the block can have no predecessors, it also
914 cannot have any <a href="#i_phi">PHI nodes</a>.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]915
Chris Lattner662c8722005-11-12 00:45:07 +0000[diff] [blame]916<p>LLVM allows an explicit section to be specified for functions. If the target
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]917 supports it, it will emit functions to the section specified.</p>
Chris Lattner662c8722005-11-12 00:45:07 +0000[diff] [blame]918
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]919<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]920 the alignment is set to zero, the alignment of the function is set by the
921 target to whatever it feels convenient. If an explicit alignment is
922 specified, the function is forced to have at least that much alignment. All
923 alignments must be a power of 2.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]924
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]925<h5>Syntax:</h5>
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]926<pre class="doc_code">
Chris Lattner0ae02092008-10-13 16:55:18 +0000[diff] [blame]927define [<a href="#linkage">linkage</a>] [<a href="#visibility">visibility</a>]
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]928 [<a href="#callingconv">cconv</a>] [<a href="#paramattrs">ret attrs</a>]
929 &lt;ResultType&gt; @&lt;FunctionName&gt; ([argument list])
930 [<a href="#fnattrs">fn Attrs</a>] [section "name"] [align N]
931 [<a href="#gc">gc</a>] { ... }
932</pre>
Devang Patel02256232008-10-07 17:48:33 +0000[diff] [blame]933
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]934</div>
935
Anton Korobeynikova97b6942007-04-25 14:27:10 +0000[diff] [blame]936<!-- ======================================================================= -->
937<div class="doc_subsection">
938 <a name="aliasstructure">Aliases</a>
939</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]940
Anton Korobeynikova97b6942007-04-25 14:27:10 +0000[diff] [blame]941<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]942
943<p>Aliases act as "second name" for the aliasee value (which can be either
944 function, global variable, another alias or bitcast of global value). Aliases
945 may have an optional <a href="#linkage">linkage type</a>, and an
946 optional <a href="#visibility">visibility style</a>.</p>
Anton Korobeynikova97b6942007-04-25 14:27:10 +0000[diff] [blame]947
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]948<h5>Syntax:</h5>
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]949<pre class="doc_code">
Duncan Sands7e99a942008-09-12 20:48:21 +0000[diff] [blame]950@&lt;Name&gt; = alias [Linkage] [Visibility] &lt;AliaseeTy&gt; @&lt;Aliasee&gt;
Bill Wendling2d8b9a82007-05-29 09:42:13 +0000[diff] [blame]951</pre>
Anton Korobeynikova97b6942007-04-25 14:27:10 +0000[diff] [blame]952
953</div>
954
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]955<!-- ======================================================================= -->
Devang Pateld1a89692010-01-11 19:35:55 +0000[diff] [blame]956<div class="doc_subsection">
957 <a name="namedmetadatastructure">Named Metadata</a>
958</div>
959
960<div class="doc_text">
961
Chris Lattnerc2f8f162010-01-15 21:50:19 +0000[diff] [blame]962<p>Named metadata is a collection of metadata. <a href="#metadata">Metadata
Dan Gohman093cb792010-07-21 18:54:18 +0000[diff] [blame]963 nodes</a> (but not metadata strings) are the only valid operands for
Chris Lattnerc2f8f162010-01-15 21:50:19 +0000[diff] [blame]964 a named metadata.</p>
Devang Pateld1a89692010-01-11 19:35:55 +0000[diff] [blame]965
966<h5>Syntax:</h5>
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]967<pre class="doc_code">
Dan Gohman093cb792010-07-21 18:54:18 +0000[diff] [blame]968; Some unnamed metadata nodes, which are referenced by the named metadata.
969!0 = metadata !{metadata !"zero"}
Devang Pateld1a89692010-01-11 19:35:55 +0000[diff] [blame]970!1 = metadata !{metadata !"one"}
Dan Gohman093cb792010-07-21 18:54:18 +0000[diff] [blame]971!2 = metadata !{metadata !"two"}
Dan Gohman58cd65f2010-07-13 19:48:13 +0000[diff] [blame]972; A named metadata.
Dan Gohman093cb792010-07-21 18:54:18 +0000[diff] [blame]973!name = !{!0, !1, !2}
Devang Pateld1a89692010-01-11 19:35:55 +0000[diff] [blame]974</pre>
Devang Pateld1a89692010-01-11 19:35:55 +0000[diff] [blame]975
976</div>
977
978<!-- ======================================================================= -->
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]979<div class="doc_subsection"><a name="paramattrs">Parameter Attributes</a></div>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]980
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]981<div class="doc_text">
982
983<p>The return type and each parameter of a function type may have a set of
984 <i>parameter attributes</i> associated with them. Parameter attributes are
985 used to communicate additional information about the result or parameters of
986 a function. Parameter attributes are considered to be part of the function,
987 not of the function type, so functions with different parameter attributes
988 can have the same function type.</p>
989
990<p>Parameter attributes are simple keywords that follow the type specified. If
991 multiple parameter attributes are needed, they are space separated. For
992 example:</p>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]993
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]994<pre class="doc_code">
Nick Lewyckydac78d82009-02-15 23:06:14 +0000[diff] [blame]995declare i32 @printf(i8* noalias nocapture, ...)
Chris Lattnerd2597d72008-10-04 18:33:34 +0000[diff] [blame]996declare i32 @atoi(i8 zeroext)
997declare signext i8 @returns_signed_char()
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]998</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]999
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1000<p>Note that any attributes for the function result (<tt>nounwind</tt>,
1001 <tt>readonly</tt>) come immediately after the argument list.</p>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1002
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1003<p>Currently, only the following parameter attributes are defined:</p>
Chris Lattner5cee13f2008-01-11 06:20:47 +0000[diff] [blame]1004
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1005<dl>
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1006 <dt><tt><b>zeroext</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1007 <dd>This indicates to the code generator that the parameter or return value
1008 should be zero-extended to a 32-bit value by the caller (for a parameter)
1009 or the callee (for a return value).</dd>
Chris Lattner5cee13f2008-01-11 06:20:47 +0000[diff] [blame]1010
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1011 <dt><tt><b>signext</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1012 <dd>This indicates to the code generator that the parameter or return value
1013 should be sign-extended to a 32-bit value by the caller (for a parameter)
1014 or the callee (for a return value).</dd>
Chris Lattner5cee13f2008-01-11 06:20:47 +0000[diff] [blame]1015
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1016 <dt><tt><b>inreg</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1017 <dd>This indicates that this parameter or return value should be treated in a
1018 special target-dependent fashion during while emitting code for a function
1019 call or return (usually, by putting it in a register as opposed to memory,
1020 though some targets use it to distinguish between two different kinds of
1021 registers). Use of this attribute is target-specific.</dd>
Chris Lattner5cee13f2008-01-11 06:20:47 +0000[diff] [blame]1022
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1023 <dt><tt><b><a name="byval">byval</a></b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1024 <dd>This indicates that the pointer parameter should really be passed by value
1025 to the function. The attribute implies that a hidden copy of the pointee
1026 is made between the caller and the callee, so the callee is unable to
1027 modify the value in the callee. This attribute is only valid on LLVM
1028 pointer arguments. It is generally used to pass structs and arrays by
1029 value, but is also valid on pointers to scalars. The copy is considered
1030 to belong to the caller not the callee (for example,
1031 <tt><a href="#readonly">readonly</a></tt> functions should not write to
1032 <tt>byval</tt> parameters). This is not a valid attribute for return
1033 values. The byval attribute also supports specifying an alignment with
1034 the align attribute. This has a target-specific effect on the code
1035 generator that usually indicates a desired alignment for the synthesized
1036 stack slot.</dd>
1037
Dan Gohman3770af52010-07-02 23:18:08 +0000[diff] [blame]1038 <dt><tt><b><a name="sret">sret</a></b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1039 <dd>This indicates that the pointer parameter specifies the address of a
1040 structure that is the return value of the function in the source program.
1041 This pointer must be guaranteed by the caller to be valid: loads and
1042 stores to the structure may be assumed by the callee to not to trap. This
1043 may only be applied to the first parameter. This is not a valid attribute
1044 for return values. </dd>
1045
Dan Gohman3770af52010-07-02 23:18:08 +0000[diff] [blame]1046 <dt><tt><b><a name="noalias">noalias</a></b></tt></dt>
Dan Gohmandf12d082010-07-02 18:41:32 +0000[diff] [blame]1047 <dd>This indicates that pointer values
1048 <a href="#pointeraliasing"><i>based</i></a> on the argument or return
Dan Gohmande256292010-07-02 23:46:54 +0000[diff] [blame]1049 value do not alias pointer values which are not <i>based</i> on it,
1050 ignoring certain "irrelevant" dependencies.
1051 For a call to the parent function, dependencies between memory
1052 references from before or after the call and from those during the call
1053 are "irrelevant" to the <tt>noalias</tt> keyword for the arguments and
1054 return value used in that call.
Dan Gohmandf12d082010-07-02 18:41:32 +0000[diff] [blame]1055 The caller shares the responsibility with the callee for ensuring that
1056 these requirements are met.
1057 For further details, please see the discussion of the NoAlias response in
Dan Gohman6c858db2010-07-06 15:26:33 +0000[diff] [blame]1058 <a href="AliasAnalysis.html#MustMayNo">alias analysis</a>.<br>
1059<br>
John McCall72ed8902010-07-06 21:07:14 +0000[diff] [blame]1060 Note that this definition of <tt>noalias</tt> is intentionally
1061 similar to the definition of <tt>restrict</tt> in C99 for function
Chris Lattner5eff9ca2010-07-06 20:51:35 +0000[diff] [blame]1062 arguments, though it is slightly weaker.
Dan Gohman6c858db2010-07-06 15:26:33 +0000[diff] [blame]1063<br>
1064 For function return values, C99's <tt>restrict</tt> is not meaningful,
1065 while LLVM's <tt>noalias</tt> is.
1066 </dd>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1067
Dan Gohman3770af52010-07-02 23:18:08 +0000[diff] [blame]1068 <dt><tt><b><a name="nocapture">nocapture</a></b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1069 <dd>This indicates that the callee does not make any copies of the pointer
1070 that outlive the callee itself. This is not a valid attribute for return
1071 values.</dd>
1072
Dan Gohman3770af52010-07-02 23:18:08 +0000[diff] [blame]1073 <dt><tt><b><a name="nest">nest</a></b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1074 <dd>This indicates that the pointer parameter can be excised using the
1075 <a href="#int_trampoline">trampoline intrinsics</a>. This is not a valid
1076 attribute for return values.</dd>
1077</dl>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1078
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1079</div>
1080
1081<!-- ======================================================================= -->
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]1082<div class="doc_subsection">
Gordon Henriksen71183b62007-12-10 03:18:06 +0000[diff] [blame]1083 <a name="gc">Garbage Collector Names</a>
1084</div>
1085
1086<div class="doc_text">
Gordon Henriksen71183b62007-12-10 03:18:06 +0000[diff] [blame]1087
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1088<p>Each function may specify a garbage collector name, which is simply a
1089 string:</p>
1090
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]1091<pre class="doc_code">
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1092define void @f() gc "name" { ... }
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1093</pre>
Gordon Henriksen71183b62007-12-10 03:18:06 +0000[diff] [blame]1094
1095<p>The compiler declares the supported values of <i>name</i>. Specifying a
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1096 collector which will cause the compiler to alter its output in order to
1097 support the named garbage collection algorithm.</p>
1098
Gordon Henriksen71183b62007-12-10 03:18:06 +0000[diff] [blame]1099</div>
1100
1101<!-- ======================================================================= -->
1102<div class="doc_subsection">
Devang Patel9eb525d2008-09-26 23:51:19 +0000[diff] [blame]1103 <a name="fnattrs">Function Attributes</a>
Devang Patelcaacdba2008-09-04 23:05:13 +0000[diff] [blame]1104</div>
1105
1106<div class="doc_text">
Devang Patel9eb525d2008-09-26 23:51:19 +0000[diff] [blame]1107
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1108<p>Function attributes are set to communicate additional information about a
1109 function. Function attributes are considered to be part of the function, not
1110 of the function type, so functions with different parameter attributes can
1111 have the same function type.</p>
Devang Patel9eb525d2008-09-26 23:51:19 +0000[diff] [blame]1112
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1113<p>Function attributes are simple keywords that follow the type specified. If
1114 multiple attributes are needed, they are space separated. For example:</p>
Devang Patelcaacdba2008-09-04 23:05:13 +0000[diff] [blame]1115
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]1116<pre class="doc_code">
Devang Patel9eb525d2008-09-26 23:51:19 +0000[diff] [blame]1117define void @f() noinline { ... }
1118define void @f() alwaysinline { ... }
1119define void @f() alwaysinline optsize { ... }
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1120define void @f() optsize { ... }
Bill Wendlingb175fa42008-09-07 10:26:33 +0000[diff] [blame]1121</pre>
Devang Patelcaacdba2008-09-04 23:05:13 +0000[diff] [blame]1122
Bill Wendlingb175fa42008-09-07 10:26:33 +0000[diff] [blame]1123<dl>
Charles Davisbe5557e2010-02-12 00:31:15 +0000[diff] [blame]1124 <dt><tt><b>alignstack(&lt;<em>n</em>&gt;)</b></tt></dt>
1125 <dd>This attribute indicates that, when emitting the prologue and epilogue,
1126 the backend should forcibly align the stack pointer. Specify the
1127 desired alignment, which must be a power of two, in parentheses.
1128
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1129 <dt><tt><b>alwaysinline</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1130 <dd>This attribute indicates that the inliner should attempt to inline this
1131 function into callers whenever possible, ignoring any active inlining size
1132 threshold for this caller.</dd>
Bill Wendlingb175fa42008-09-07 10:26:33 +0000[diff] [blame]1133
Jakob Stoklund Olesen74bb06c2010-02-06 01:16:28 +0000[diff] [blame]1134 <dt><tt><b>inlinehint</b></tt></dt>
1135 <dd>This attribute indicates that the source code contained a hint that inlining
1136 this function is desirable (such as the "inline" keyword in C/C++). It
1137 is just a hint; it imposes no requirements on the inliner.</dd>
1138
Nick Lewycky14b58da2010-07-06 18:24:09 +0000[diff] [blame]1139 <dt><tt><b>naked</b></tt></dt>
1140 <dd>This attribute disables prologue / epilogue emission for the function.
1141 This can have very system-specific consequences.</dd>
1142
1143 <dt><tt><b>noimplicitfloat</b></tt></dt>
1144 <dd>This attributes disables implicit floating point instructions.</dd>
1145
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1146 <dt><tt><b>noinline</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1147 <dd>This attribute indicates that the inliner should never inline this
1148 function in any situation. This attribute may not be used together with
1149 the <tt>alwaysinline</tt> attribute.</dd>
Devang Patel9eb525d2008-09-26 23:51:19 +0000[diff] [blame]1150
Nick Lewycky14b58da2010-07-06 18:24:09 +0000[diff] [blame]1151 <dt><tt><b>noredzone</b></tt></dt>
1152 <dd>This attribute indicates that the code generator should not use a red
1153 zone, even if the target-specific ABI normally permits it.</dd>
Devang Patel9eb525d2008-09-26 23:51:19 +0000[diff] [blame]1154
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1155 <dt><tt><b>noreturn</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1156 <dd>This function attribute indicates that the function never returns
1157 normally. This produces undefined behavior at runtime if the function
1158 ever does dynamically return.</dd>
Bill Wendlinga8130172008-11-13 01:02:51 +0000[diff] [blame]1159
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1160 <dt><tt><b>nounwind</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1161 <dd>This function attribute indicates that the function never returns with an
1162 unwind or exceptional control flow. If the function does unwind, its
1163 runtime behavior is undefined.</dd>
Bill Wendling0f5541e2008-11-26 19:07:40 +0000[diff] [blame]1164
Nick Lewycky14b58da2010-07-06 18:24:09 +0000[diff] [blame]1165 <dt><tt><b>optsize</b></tt></dt>
1166 <dd>This attribute suggests that optimization passes and code generator passes
1167 make choices that keep the code size of this function low, and otherwise
1168 do optimizations specifically to reduce code size.</dd>
1169
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1170 <dt><tt><b>readnone</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1171 <dd>This attribute indicates that the function computes its result (or decides
1172 to unwind an exception) based strictly on its arguments, without
1173 dereferencing any pointer arguments or otherwise accessing any mutable
1174 state (e.g. memory, control registers, etc) visible to caller functions.
1175 It does not write through any pointer arguments
1176 (including <tt><a href="#byval">byval</a></tt> arguments) and never
1177 changes any state visible to callers. This means that it cannot unwind
1178 exceptions by calling the <tt>C++</tt> exception throwing methods, but
1179 could use the <tt>unwind</tt> instruction.</dd>
Devang Patel310fd4a2009-06-12 19:45:19 +0000[diff] [blame]1180
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1181 <dt><tt><b><a name="readonly">readonly</a></b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1182 <dd>This attribute indicates that the function does not write through any
1183 pointer arguments (including <tt><a href="#byval">byval</a></tt>
1184 arguments) or otherwise modify any state (e.g. memory, control registers,
1185 etc) visible to caller functions. It may dereference pointer arguments
1186 and read state that may be set in the caller. A readonly function always
1187 returns the same value (or unwinds an exception identically) when called
1188 with the same set of arguments and global state. It cannot unwind an
1189 exception by calling the <tt>C++</tt> exception throwing methods, but may
1190 use the <tt>unwind</tt> instruction.</dd>
Anton Korobeynikovc8ce7b082009-07-17 18:07:26 +0000[diff] [blame]1191
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1192 <dt><tt><b><a name="ssp">ssp</a></b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1193 <dd>This attribute indicates that the function should emit a stack smashing
1194 protector. It is in the form of a "canary"&mdash;a random value placed on
1195 the stack before the local variables that's checked upon return from the
1196 function to see if it has been overwritten. A heuristic is used to
1197 determine if a function needs stack protectors or not.<br>
1198<br>
1199 If a function that has an <tt>ssp</tt> attribute is inlined into a
1200 function that doesn't have an <tt>ssp</tt> attribute, then the resulting
1201 function will have an <tt>ssp</tt> attribute.</dd>
1202
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1203 <dt><tt><b>sspreq</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1204 <dd>This attribute indicates that the function should <em>always</em> emit a
1205 stack smashing protector. This overrides
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1206 the <tt><a href="#ssp">ssp</a></tt> function attribute.<br>
1207<br>
1208 If a function that has an <tt>sspreq</tt> attribute is inlined into a
1209 function that doesn't have an <tt>sspreq</tt> attribute or which has
1210 an <tt>ssp</tt> attribute, then the resulting function will have
1211 an <tt>sspreq</tt> attribute.</dd>
Bill Wendlingb175fa42008-09-07 10:26:33 +0000[diff] [blame]1212</dl>
1213
Devang Patelcaacdba2008-09-04 23:05:13 +0000[diff] [blame]1214</div>
1215
1216<!-- ======================================================================= -->
1217<div class="doc_subsection">
Chris Lattner93564892006-04-08 04:40:53 +0000[diff] [blame]1218 <a name="moduleasm">Module-Level Inline Assembly</a>
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]1219</div>
1220
1221<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1222
1223<p>Modules may contain "module-level inline asm" blocks, which corresponds to
1224 the GCC "file scope inline asm" blocks. These blocks are internally
1225 concatenated by LLVM and treated as a single unit, but may be separated in
1226 the <tt>.ll</tt> file if desired. The syntax is very simple:</p>
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]1227
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]1228<pre class="doc_code">
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]1229module asm "inline asm code goes here"
1230module asm "more can go here"
1231</pre>
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]1232
1233<p>The strings can contain any character by escaping non-printable characters.
1234 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]1235 for the number.</p>
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]1236
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1237<p>The inline asm code is simply printed to the machine code .s file when
1238 assembly code is generated.</p>
1239
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]1240</div>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]1241
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1242<!-- ======================================================================= -->
1243<div class="doc_subsection">
1244 <a name="datalayout">Data Layout</a>
1245</div>
1246
1247<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1248
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1249<p>A module may specify a target specific data layout string that specifies how
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1250 data is to be laid out in memory. The syntax for the data layout is
1251 simply:</p>
1252
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]1253<pre class="doc_code">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1254target datalayout = "<i>layout specification</i>"
1255</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1256
1257<p>The <i>layout specification</i> consists of a list of specifications
1258 separated by the minus sign character ('-'). Each specification starts with
1259 a letter and may include other information after the letter to define some
1260 aspect of the data layout. The specifications accepted are as follows:</p>
1261
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1262<dl>
1263 <dt><tt>E</tt></dt>
1264 <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]1265 bits with the most significance have the lowest address location.</dd>
1266
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1267 <dt><tt>e</tt></dt>
Chris Lattner67c37d12008-08-05 18:29:16 +0000[diff] [blame]1268 <dd>Specifies that the target lays out data in little-endian form. That is,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1269 the bits with the least significance have the lowest address
1270 location.</dd>
1271
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1272 <dt><tt>p:<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]1273 <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]1274 <i>preferred</i> alignments. All sizes are in bits. Specifying
1275 the <i>pref</i> alignment is optional. If omitted, the
1276 preceding <tt>:</tt> should be omitted too.</dd>
1277
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1278 <dt><tt>i<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1279 <dd>This specifies the alignment for an integer type of a given bit
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1280 <i>size</i>. The value of <i>size</i> must be in the range [1,2^23).</dd>
1281
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1282 <dt><tt>v<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]1283 <dd>This specifies the alignment for a vector type of a given bit
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1284 <i>size</i>.</dd>
1285
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1286 <dt><tt>f<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]1287 <dd>This specifies the alignment for a floating point type of a given bit
Dale Johannesence522852010-05-28 18:54:47 +0000[diff] [blame]1288 <i>size</i>. Only values of <i>size</i> that are supported by the target
1289 will work. 32 (float) and 64 (double) are supported on all targets;
1290 80 or 128 (different flavors of long double) are also supported on some
1291 targets.
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1292
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1293 <dt><tt>a<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1294 <dd>This specifies the alignment for an aggregate type of a given bit
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1295 <i>size</i>.</dd>
1296
Daniel Dunbar7921a592009-06-08 22:17:53 +0000[diff] [blame]1297 <dt><tt>s<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1298 <dd>This specifies the alignment for a stack object of a given bit
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1299 <i>size</i>.</dd>
Chris Lattnera381eff2009-11-07 09:35:34 +0000[diff] [blame]1300
1301 <dt><tt>n<i>size1</i>:<i>size2</i>:<i>size3</i>...</tt></dt>
1302 <dd>This specifies a set of native integer widths for the target CPU
1303 in bits. For example, it might contain "n32" for 32-bit PowerPC,
1304 "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]1305 this set are considered to support most general arithmetic
Chris Lattnera381eff2009-11-07 09:35:34 +0000[diff] [blame]1306 operations efficiently.</dd>
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1307</dl>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1308
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1309<p>When constructing the data layout for a given target, LLVM starts with a
Dan Gohman61110ae2010-04-28 00:36:01 +0000[diff] [blame]1310 default set of specifications which are then (possibly) overridden by the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1311 specifications in the <tt>datalayout</tt> keyword. The default specifications
1312 are given in this list:</p>
1313
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1314<ul>
1315 <li><tt>E</tt> - big endian</li>
Dan Gohman8ad777d2010-02-23 02:44:03 +0000[diff] [blame]1316 <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]1317 <li><tt>i1:8:8</tt> - i1 is 8-bit (byte) aligned</li>
1318 <li><tt>i8:8:8</tt> - i8 is 8-bit (byte) aligned</li>
1319 <li><tt>i16:16:16</tt> - i16 is 16-bit aligned</li>
1320 <li><tt>i32:32:32</tt> - i32 is 32-bit aligned</li>
Chris Lattner67c37d12008-08-05 18:29:16 +0000[diff] [blame]1321 <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]1322 alignment of 64-bits</li>
1323 <li><tt>f32:32:32</tt> - float is 32-bit aligned</li>
1324 <li><tt>f64:64:64</tt> - double is 64-bit aligned</li>
1325 <li><tt>v64:64:64</tt> - 64-bit vector is 64-bit aligned</li>
1326 <li><tt>v128:128:128</tt> - 128-bit vector is 128-bit aligned</li>
1327 <li><tt>a0:0:1</tt> - aggregates are 8-bit aligned</li>
Daniel Dunbar7921a592009-06-08 22:17:53 +0000[diff] [blame]1328 <li><tt>s0:64:64</tt> - stack objects are 64-bit aligned</li>
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1329</ul>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1330
1331<p>When LLVM is determining the alignment for a given type, it uses the
1332 following rules:</p>
1333
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1334<ol>
1335 <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]1336 specification is used.</li>
1337
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1338 <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]1339 smallest integer type that is larger than the bitwidth of the sought type
1340 is used. If none of the specifications are larger than the bitwidth then
1341 the the largest integer type is used. For example, given the default
1342 specifications above, the i7 type will use the alignment of i8 (next
1343 largest) while both i65 and i256 will use the alignment of i64 (largest
1344 specified).</li>
1345
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1346 <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]1347 largest vector type that is smaller than the sought vector type will be
1348 used as a fall back. This happens because &lt;128 x double&gt; can be
1349 implemented in terms of 64 &lt;2 x double&gt;, for example.</li>
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1350</ol>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1351
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1352</div>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]1353
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1354<!-- ======================================================================= -->
1355<div class="doc_subsection">
1356 <a name="pointeraliasing">Pointer Aliasing Rules</a>
1357</div>
1358
1359<div class="doc_text">
1360
Andreas Bolka8ae4e242009-07-29 00:02:05 +0000[diff] [blame]1361<p>Any memory access must be done through a pointer value associated
Andreas Bolkae39f0332009-07-27 20:37:10 +0000[diff] [blame]1362with an address range of the memory access, otherwise the behavior
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1363is undefined. Pointer values are associated with address ranges
1364according to the following rules:</p>
1365
1366<ul>
Dan Gohmandf12d082010-07-02 18:41:32 +0000[diff] [blame]1367 <li>A pointer value is associated with the addresses associated with
1368 any value it is <i>based</i> on.
Andreas Bolka8ae4e242009-07-29 00:02:05 +0000[diff] [blame]1369 <li>An address of a global variable is associated with the address
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1370 range of the variable's storage.</li>
1371 <li>The result value of an allocation instruction is associated with
1372 the address range of the allocated storage.</li>
1373 <li>A null pointer in the default address-space is associated with
Andreas Bolka8ae4e242009-07-29 00:02:05 +0000[diff] [blame]1374 no address.</li>
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1375 <li>An integer constant other than zero or a pointer value returned
1376 from a function not defined within LLVM may be associated with address
1377 ranges allocated through mechanisms other than those provided by
Andreas Bolka8ae4e242009-07-29 00:02:05 +0000[diff] [blame]1378 LLVM. Such ranges shall not overlap with any ranges of addresses
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1379 allocated by mechanisms provided by LLVM.</li>
Dan Gohmandf12d082010-07-02 18:41:32 +0000[diff] [blame]1380</ul>
1381
1382<p>A pointer value is <i>based</i> on another pointer value according
1383 to the following rules:</p>
1384
1385<ul>
1386 <li>A pointer value formed from a
1387 <tt><a href="#i_getelementptr">getelementptr</a></tt> operation
1388 is <i>based</i> on the first operand of the <tt>getelementptr</tt>.</li>
1389 <li>The result value of a
1390 <tt><a href="#i_bitcast">bitcast</a></tt> is <i>based</i> on the operand
1391 of the <tt>bitcast</tt>.</li>
1392 <li>A pointer value formed by an
1393 <tt><a href="#i_inttoptr">inttoptr</a></tt> is <i>based</i> on all
1394 pointer values that contribute (directly or indirectly) to the
1395 computation of the pointer's value.</li>
1396 <li>The "<i>based</i> on" relationship is transitive.</li>
1397</ul>
1398
1399<p>Note that this definition of <i>"based"</i> is intentionally
1400 similar to the definition of <i>"based"</i> in C99, though it is
1401 slightly weaker.</p>
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1402
1403<p>LLVM IR does not associate types with memory. The result type of a
Andreas Bolka8ae4e242009-07-29 00:02:05 +0000[diff] [blame]1404<tt><a href="#i_load">load</a></tt> merely indicates the size and
1405alignment of the memory from which to load, as well as the
Dan Gohman4eb47192010-06-17 19:23:50 +0000[diff] [blame]1406interpretation of the value. The first operand type of a
Andreas Bolka8ae4e242009-07-29 00:02:05 +0000[diff] [blame]1407<tt><a href="#i_store">store</a></tt> similarly only indicates the size
1408and alignment of the store.</p>
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1409
1410<p>Consequently, type-based alias analysis, aka TBAA, aka
1411<tt>-fstrict-aliasing</tt>, is not applicable to general unadorned
1412LLVM IR. <a href="#metadata">Metadata</a> may be used to encode
1413additional information which specialized optimization passes may use
1414to implement type-based alias analysis.</p>
1415
1416</div>
1417
Jeffrey Yasskin5d284ae2010-04-26 21:21:24 +0000[diff] [blame]1418<!-- ======================================================================= -->
1419<div class="doc_subsection">
1420 <a name="volatile">Volatile Memory Accesses</a>
1421</div>
1422
1423<div class="doc_text">
1424
1425<p>Certain memory accesses, such as <a href="#i_load"><tt>load</tt></a>s, <a
1426href="#i_store"><tt>store</tt></a>s, and <a
1427href="#int_memcpy"><tt>llvm.memcpy</tt></a>s may be marked <tt>volatile</tt>.
1428The optimizers must not change the number of volatile operations or change their
1429order of execution relative to other volatile operations. The optimizers
1430<i>may</i> change the order of volatile operations relative to non-volatile
1431operations. This is not Java's "volatile" and has no cross-thread
1432synchronization behavior.</p>
1433
1434</div>
1435
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1436<!-- *********************************************************************** -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1437<div class="doc_section"> <a name="typesystem">Type System</a> </div>
1438<!-- *********************************************************************** -->
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]1439
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1440<div class="doc_text">
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]1441
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1442<p>The LLVM type system is one of the most important features of the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1443 intermediate representation. Being typed enables a number of optimizations
1444 to be performed on the intermediate representation directly, without having
1445 to do extra analyses on the side before the transformation. A strong type
1446 system makes it easier to read the generated code and enables novel analyses
1447 and transformations that are not feasible to perform on normal three address
1448 code representations.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]1449
1450</div>
1451
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1452<!-- ======================================================================= -->
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1453<div class="doc_subsection"> <a name="t_classifications">Type
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1454Classifications</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1455
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1456<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1457
1458<p>The types fall into a few useful classifications:</p>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]1459
1460<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1461 <tbody>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1462 <tr><th>Classification</th><th>Types</th></tr>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1463 <tr>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1464 <td><a href="#t_integer">integer</a></td>
Reid Spencer138249b2007-05-16 18:44:01 +0000[diff] [blame]1465 <td><tt>i1, i2, i3, ... i8, ... i16, ... i32, ... i64, ... </tt></td>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1466 </tr>
1467 <tr>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1468 <td><a href="#t_floating">floating point</a></td>
1469 <td><tt>float, double, x86_fp80, fp128, ppc_fp128</tt></td>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1470 </tr>
1471 <tr>
1472 <td><a name="t_firstclass">first class</a></td>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1473 <td><a href="#t_integer">integer</a>,
1474 <a href="#t_floating">floating point</a>,
1475 <a href="#t_pointer">pointer</a>,
Dan Gohman08783a882008-06-18 18:42:13 +0000[diff] [blame]1476 <a href="#t_vector">vector</a>,
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]1477 <a href="#t_struct">structure</a>,
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]1478 <a href="#t_union">union</a>,
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]1479 <a href="#t_array">array</a>,
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1480 <a href="#t_label">label</a>,
1481 <a href="#t_metadata">metadata</a>.
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1482 </td>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1483 </tr>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1484 <tr>
1485 <td><a href="#t_primitive">primitive</a></td>
1486 <td><a href="#t_label">label</a>,
1487 <a href="#t_void">void</a>,
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1488 <a href="#t_floating">floating point</a>,
1489 <a href="#t_metadata">metadata</a>.</td>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1490 </tr>
1491 <tr>
1492 <td><a href="#t_derived">derived</a></td>
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]1493 <td><a href="#t_array">array</a>,
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1494 <a href="#t_function">function</a>,
1495 <a href="#t_pointer">pointer</a>,
1496 <a href="#t_struct">structure</a>,
1497 <a href="#t_pstruct">packed structure</a>,
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]1498 <a href="#t_union">union</a>,
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1499 <a href="#t_vector">vector</a>,
1500 <a href="#t_opaque">opaque</a>.
Dan Gohman93bf60d2008-10-14 16:32:04 +0000[diff] [blame]1501 </td>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1502 </tr>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1503 </tbody>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1504</table>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]1505
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1506<p>The <a href="#t_firstclass">first class</a> types are perhaps the most
1507 important. Values of these types are the only ones which can be produced by
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]1508 instructions.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1509
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1510</div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1511
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1512<!-- ======================================================================= -->
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1513<div class="doc_subsection"> <a name="t_primitive">Primitive Types</a> </div>
Chris Lattner43542b32008-01-04 04:34:14 +0000[diff] [blame]1514
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1515<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1516
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1517<p>The primitive types are the fundamental building blocks of the LLVM
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1518 system.</p>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1519
Chris Lattner43542b32008-01-04 04:34:14 +0000[diff] [blame]1520</div>
1521
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1522<!-- _______________________________________________________________________ -->
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]1523<div class="doc_subsubsection"> <a name="t_integer">Integer Type</a> </div>
1524
1525<div class="doc_text">
1526
1527<h5>Overview:</h5>
1528<p>The integer type is a very simple type that simply specifies an arbitrary
1529 bit width for the integer type desired. Any bit width from 1 bit to
1530 2<sup>23</sup>-1 (about 8 million) can be specified.</p>
1531
1532<h5>Syntax:</h5>
1533<pre>
1534 iN
1535</pre>
1536
1537<p>The number of bits the integer will occupy is specified by the <tt>N</tt>
1538 value.</p>
1539
1540<h5>Examples:</h5>
1541<table class="layout">
1542 <tr class="layout">
1543 <td class="left"><tt>i1</tt></td>
1544 <td class="left">a single-bit integer.</td>
1545 </tr>
1546 <tr class="layout">
1547 <td class="left"><tt>i32</tt></td>
1548 <td class="left">a 32-bit integer.</td>
1549 </tr>
1550 <tr class="layout">
1551 <td class="left"><tt>i1942652</tt></td>
1552 <td class="left">a really big integer of over 1 million bits.</td>
1553 </tr>
1554</table>
1555
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]1556</div>
1557
1558<!-- _______________________________________________________________________ -->
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1559<div class="doc_subsubsection"> <a name="t_floating">Floating Point Types</a> </div>
1560
1561<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1562
1563<table>
1564 <tbody>
1565 <tr><th>Type</th><th>Description</th></tr>
1566 <tr><td><tt>float</tt></td><td>32-bit floating point value</td></tr>
1567 <tr><td><tt>double</tt></td><td>64-bit floating point value</td></tr>
1568 <tr><td><tt>fp128</tt></td><td>128-bit floating point value (112-bit mantissa)</td></tr>
1569 <tr><td><tt>x86_fp80</tt></td><td>80-bit floating point value (X87)</td></tr>
1570 <tr><td><tt>ppc_fp128</tt></td><td>128-bit floating point value (two 64-bits)</td></tr>
1571 </tbody>
1572</table>
1573
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1574</div>
1575
1576<!-- _______________________________________________________________________ -->
1577<div class="doc_subsubsection"> <a name="t_void">Void Type</a> </div>
1578
1579<div class="doc_text">
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1580
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1581<h5>Overview:</h5>
1582<p>The void type does not represent any value and has no size.</p>
1583
1584<h5>Syntax:</h5>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1585<pre>
1586 void
1587</pre>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1588
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1589</div>
1590
1591<!-- _______________________________________________________________________ -->
1592<div class="doc_subsubsection"> <a name="t_label">Label Type</a> </div>
1593
1594<div class="doc_text">
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1595
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1596<h5>Overview:</h5>
1597<p>The label type represents code labels.</p>
1598
1599<h5>Syntax:</h5>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1600<pre>
1601 label
1602</pre>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1603
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1604</div>
1605
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1606<!-- _______________________________________________________________________ -->
1607<div class="doc_subsubsection"> <a name="t_metadata">Metadata Type</a> </div>
1608
1609<div class="doc_text">
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1610
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1611<h5>Overview:</h5>
Nick Lewycky93e06a52009-09-27 23:27:42 +0000[diff] [blame]1612<p>The metadata type represents embedded metadata. No derived types may be
1613 created from metadata except for <a href="#t_function">function</a>
1614 arguments.
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1615
1616<h5>Syntax:</h5>
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1617<pre>
1618 metadata
1619</pre>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1620
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1621</div>
1622
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1623
1624<!-- ======================================================================= -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1625<div class="doc_subsection"> <a name="t_derived">Derived Types</a> </div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1626
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1627<div class="doc_text">
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1628
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1629<p>The real power in LLVM comes from the derived types in the system. This is
1630 what allows a programmer to represent arrays, functions, pointers, and other
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]1631 useful types. Each of these types contain one or more element types which
1632 may be a primitive type, or another derived type. For example, it is
1633 possible to have a two dimensional array, using an array as the element type
1634 of another array.</p>
Dan Gohman142ccc02009-01-24 15:58:40 +0000[diff] [blame]1635
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]1636
1637</div>
1638
1639<!-- _______________________________________________________________________ -->
1640<div class="doc_subsubsection"> <a name="t_aggregate">Aggregate Types</a> </div>
1641
1642<div class="doc_text">
1643
1644<p>Aggregate Types are a subset of derived types that can contain multiple
1645 member types. <a href="#t_array">Arrays</a>,
1646 <a href="#t_struct">structs</a>, <a href="#t_vector">vectors</a> and
1647 <a href="#t_union">unions</a> are aggregate types.</p>
1648
1649</div>
1650
Reid Spencer138249b2007-05-16 18:44:01 +0000[diff] [blame]1651<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1652<div class="doc_subsubsection"> <a name="t_array">Array Type</a> </div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1653
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1654<div class="doc_text">
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1655
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1656<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1657<p>The array type is a very simple derived type that arranges elements
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1658 sequentially in memory. The array type requires a size (number of elements)
1659 and an underlying data type.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1660
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]1661<h5>Syntax:</h5>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1662<pre>
1663 [&lt;# elements&gt; x &lt;elementtype&gt;]
1664</pre>
1665
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1666<p>The number of elements is a constant integer value; <tt>elementtype</tt> may
1667 be any type with a size.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1668
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]1669<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1670<table class="layout">
1671 <tr class="layout">
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]1672 <td class="left"><tt>[40 x i32]</tt></td>
1673 <td class="left">Array of 40 32-bit integer values.</td>
1674 </tr>
1675 <tr class="layout">
1676 <td class="left"><tt>[41 x i32]</tt></td>
1677 <td class="left">Array of 41 32-bit integer values.</td>
1678 </tr>
1679 <tr class="layout">
1680 <td class="left"><tt>[4 x i8]</tt></td>
1681 <td class="left">Array of 4 8-bit integer values.</td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1682 </tr>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1683</table>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1684<p>Here are some examples of multidimensional arrays:</p>
1685<table class="layout">
1686 <tr class="layout">
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]1687 <td class="left"><tt>[3 x [4 x i32]]</tt></td>
1688 <td class="left">3x4 array of 32-bit integer values.</td>
1689 </tr>
1690 <tr class="layout">
1691 <td class="left"><tt>[12 x [10 x float]]</tt></td>
1692 <td class="left">12x10 array of single precision floating point values.</td>
1693 </tr>
1694 <tr class="layout">
1695 <td class="left"><tt>[2 x [3 x [4 x i16]]]</tt></td>
1696 <td class="left">2x3x4 array of 16-bit integer values.</td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1697 </tr>
1698</table>
Chris Lattnerc0ad71e2005-06-24 17:22:57 +0000[diff] [blame]1699
Dan Gohmanc74bc282009-11-09 19:01:53 +0000[diff] [blame]1700<p>There is no restriction on indexing beyond the end of the array implied by
1701 a static type (though there are restrictions on indexing beyond the bounds
1702 of an allocated object in some cases). This means that single-dimension
1703 'variable sized array' addressing can be implemented in LLVM with a zero
1704 length array type. An implementation of 'pascal style arrays' in LLVM could
1705 use the type "<tt>{ i32, [0 x float]}</tt>", for example.</p>
Chris Lattnerc0ad71e2005-06-24 17:22:57 +0000[diff] [blame]1706
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1707</div>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1708
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1709<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1710<div class="doc_subsubsection"> <a name="t_function">Function Type</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1711
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1712<div class="doc_text">
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]1713
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1714<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1715<p>The function type can be thought of as a function signature. It consists of
1716 a return type and a list of formal parameter types. The return type of a
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]1717 function type is a scalar type, a void type, a struct type, or a union
1718 type. If the return type is a struct type then all struct elements must be
1719 of first class types, and the struct must have at least one element.</p>
Devang Pateld6cff512008-03-10 20:49:15 +0000[diff] [blame]1720
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1721<h5>Syntax:</h5>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]1722<pre>
Nick Lewycky14d1ccc2009-09-27 07:55:32 +0000[diff] [blame]1723 &lt;returntype&gt; (&lt;parameter list&gt;)
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]1724</pre>
1725
John Criswell4c0cf7f2005-10-24 16:17:18 +0000[diff] [blame]1726<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]1727 specifiers. Optionally, the parameter list may include a type <tt>...</tt>,
1728 which indicates that the function takes a variable number of arguments.
1729 Variable argument functions can access their arguments with
1730 the <a href="#int_varargs">variable argument handling intrinsic</a>
Chris Lattner47f2a832010-03-02 06:36:51 +0000[diff] [blame]1731 functions. '<tt>&lt;returntype&gt;</tt>' is any type except
Nick Lewycky93e06a52009-09-27 23:27:42 +0000[diff] [blame]1732 <a href="#t_label">label</a>.</p>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]1733
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1734<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1735<table class="layout">
1736 <tr class="layout">
Reid Spencer58c08712006-12-31 07:18:34 +0000[diff] [blame]1737 <td class="left"><tt>i32 (i32)</tt></td>
1738 <td class="left">function taking an <tt>i32</tt>, returning an <tt>i32</tt>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1739 </td>
Reid Spencer58c08712006-12-31 07:18:34 +0000[diff] [blame]1740 </tr><tr class="layout">
Chris Lattner47f2a832010-03-02 06:36:51 +0000[diff] [blame]1741 <td class="left"><tt>float&nbsp;(i16,&nbsp;i32&nbsp;*)&nbsp;*
Reid Spencer655dcc62006-12-31 07:20:23 +0000[diff] [blame]1742 </tt></td>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]1743 <td class="left"><a href="#t_pointer">Pointer</a> to a function that takes
Chris Lattner47f2a832010-03-02 06:36:51 +0000[diff] [blame]1744 an <tt>i16</tt> and a <a href="#t_pointer">pointer</a> to <tt>i32</tt>,
1745 returning <tt>float</tt>.
Reid Spencer58c08712006-12-31 07:18:34 +0000[diff] [blame]1746 </td>
1747 </tr><tr class="layout">
1748 <td class="left"><tt>i32 (i8*, ...)</tt></td>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]1749 <td class="left">A vararg function that takes at least one
1750 <a href="#t_pointer">pointer</a> to <tt>i8 </tt> (char in C),
1751 which returns an integer. This is the signature for <tt>printf</tt> in
Reid Spencer58c08712006-12-31 07:18:34 +0000[diff] [blame]1752 LLVM.
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1753 </td>
Devang Patele3dfc1c2008-03-24 05:35:41 +0000[diff] [blame]1754 </tr><tr class="layout">
1755 <td class="left"><tt>{i32, i32} (i32)</tt></td>
Nick Lewycky14d1ccc2009-09-27 07:55:32 +0000[diff] [blame]1756 <td class="left">A function taking an <tt>i32</tt>, returning a
1757 <a href="#t_struct">structure</a> containing two <tt>i32</tt> values
Devang Patele3dfc1c2008-03-24 05:35:41 +0000[diff] [blame]1758 </td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1759 </tr>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1760</table>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]1761
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1762</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1763
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1764<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1765<div class="doc_subsubsection"> <a name="t_struct">Structure Type</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1766
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1767<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1768
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1769<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1770<p>The structure type is used to represent a collection of data members together
1771 in memory. The packing of the field types is defined to match the ABI of the
1772 underlying processor. The elements of a structure may be any type that has a
1773 size.</p>
1774
Jeffrey Yasskinf991bbb2010-01-11 19:19:26 +0000[diff] [blame]1775<p>Structures in memory are accessed using '<tt><a href="#i_load">load</a></tt>'
1776 and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a field
1777 with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.
1778 Structures in registers are accessed using the
1779 '<tt><a href="#i_extractvalue">extractvalue</a></tt>' and
1780 '<tt><a href="#i_insertvalue">insertvalue</a></tt>' instructions.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1781<h5>Syntax:</h5>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1782<pre>
1783 { &lt;type list&gt; }
1784</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1785
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1786<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1787<table class="layout">
1788 <tr class="layout">
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]1789 <td class="left"><tt>{ i32, i32, i32 }</tt></td>
1790 <td class="left">A triple of three <tt>i32</tt> values</td>
1791 </tr><tr class="layout">
1792 <td class="left"><tt>{&nbsp;float,&nbsp;i32&nbsp;(i32)&nbsp;*&nbsp;}</tt></td>
1793 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1794 second element is a <a href="#t_pointer">pointer</a> to a
1795 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1796 an <tt>i32</tt>.</td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1797 </tr>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1798</table>
Dan Gohman142ccc02009-01-24 15:58:40 +0000[diff] [blame]1799
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1800</div>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1801
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1802<!-- _______________________________________________________________________ -->
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]1803<div class="doc_subsubsection"> <a name="t_pstruct">Packed Structure Type</a>
1804</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1805
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]1806<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1807
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]1808<h5>Overview:</h5>
1809<p>The packed structure type is used to represent a collection of data members
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1810 together in memory. There is no padding between fields. Further, the
1811 alignment of a packed structure is 1 byte. The elements of a packed
1812 structure may be any type that has a size.</p>
1813
1814<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt> and
1815 '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a field with
1816 the '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
1817
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]1818<h5>Syntax:</h5>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1819<pre>
1820 &lt; { &lt;type list&gt; } &gt;
1821</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1822
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]1823<h5>Examples:</h5>
1824<table class="layout">
1825 <tr class="layout">
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]1826 <td class="left"><tt>&lt; { i32, i32, i32 } &gt;</tt></td>
1827 <td class="left">A triple of three <tt>i32</tt> values</td>
1828 </tr><tr class="layout">
Bill Wendlingb175fa42008-09-07 10:26:33 +0000[diff] [blame]1829 <td class="left">
1830<tt>&lt;&nbsp;{&nbsp;float,&nbsp;i32&nbsp;(i32)*&nbsp;}&nbsp;&gt;</tt></td>
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]1831 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1832 second element is a <a href="#t_pointer">pointer</a> to a
1833 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1834 an <tt>i32</tt>.</td>
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]1835 </tr>
1836</table>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1837
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]1838</div>
1839
1840<!-- _______________________________________________________________________ -->
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]1841<div class="doc_subsubsection"> <a name="t_union">Union Type</a> </div>
1842
1843<div class="doc_text">
1844
1845<h5>Overview:</h5>
1846<p>A union type describes an object with size and alignment suitable for
1847 an object of any one of a given set of types (also known as an "untagged"
1848 union). It is similar in concept and usage to a
1849 <a href="#t_struct">struct</a>, except that all members of the union
1850 have an offset of zero. The elements of a union may be any type that has a
1851 size. Unions must have at least one member - empty unions are not allowed.
1852 </p>
1853
1854<p>The size of the union as a whole will be the size of its largest member,
1855 and the alignment requirements of the union as a whole will be the largest
1856 alignment requirement of any member.</p>
1857
Dan Gohman1ad14992010-02-25 16:51:31 +0000[diff] [blame]1858<p>Union members are accessed using '<tt><a href="#i_load">load</a></tt> and
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]1859 '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a field with
1860 the '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.
1861 Since all members are at offset zero, the getelementptr instruction does
1862 not affect the address, only the type of the resulting pointer.</p>
1863
1864<h5>Syntax:</h5>
1865<pre>
1866 union { &lt;type list&gt; }
1867</pre>
1868
1869<h5>Examples:</h5>
1870<table class="layout">
1871 <tr class="layout">
1872 <td class="left"><tt>union { i32, i32*, float }</tt></td>
1873 <td class="left">A union of three types: an <tt>i32</tt>, a pointer to
1874 an <tt>i32</tt>, and a <tt>float</tt>.</td>
1875 </tr><tr class="layout">
1876 <td class="left">
1877 <tt>union {&nbsp;float,&nbsp;i32&nbsp;(i32)&nbsp;*&nbsp;}</tt></td>
1878 <td class="left">A union, where the first element is a <tt>float</tt> and the
1879 second element is a <a href="#t_pointer">pointer</a> to a
1880 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1881 an <tt>i32</tt>.</td>
1882 </tr>
1883</table>
1884
1885</div>
1886
1887<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1888<div class="doc_subsubsection"> <a name="t_pointer">Pointer Type</a> </div>
Chris Lattner4a67c912009-02-08 19:53:29 +0000[diff] [blame]1889
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1890<div class="doc_text">
1891
1892<h5>Overview:</h5>
Dan Gohman88481112010-02-25 16:50:07 +0000[diff] [blame]1893<p>The pointer type is used to specify memory locations.
1894 Pointers are commonly used to reference objects in memory.</p>
1895
1896<p>Pointer types may have an optional address space attribute defining the
1897 numbered address space where the pointed-to object resides. The default
1898 address space is number zero. The semantics of non-zero address
1899 spaces are target-specific.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1900
1901<p>Note that LLVM does not permit pointers to void (<tt>void*</tt>) nor does it
1902 permit pointers to labels (<tt>label*</tt>). Use <tt>i8*</tt> instead.</p>
Chris Lattner4a67c912009-02-08 19:53:29 +0000[diff] [blame]1903
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]1904<h5>Syntax:</h5>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1905<pre>
1906 &lt;type&gt; *
1907</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1908
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]1909<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1910<table class="layout">
1911 <tr class="layout">
Dan Gohman623806e2009-01-04 23:44:43 +0000[diff] [blame]1912 <td class="left"><tt>[4 x i32]*</tt></td>
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]1913 <td class="left">A <a href="#t_pointer">pointer</a> to <a
1914 href="#t_array">array</a> of four <tt>i32</tt> values.</td>
1915 </tr>
1916 <tr class="layout">
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]1917 <td class="left"><tt>i32 (i32*) *</tt></td>
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]1918 <td class="left"> A <a href="#t_pointer">pointer</a> to a <a
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1919 href="#t_function">function</a> that takes an <tt>i32*</tt>, returning an
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]1920 <tt>i32</tt>.</td>
1921 </tr>
1922 <tr class="layout">
1923 <td class="left"><tt>i32 addrspace(5)*</tt></td>
1924 <td class="left">A <a href="#t_pointer">pointer</a> to an <tt>i32</tt> value
1925 that resides in address space #5.</td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1926 </tr>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1927</table>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1928
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1929</div>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1930
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1931<!-- _______________________________________________________________________ -->
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]1932<div class="doc_subsubsection"> <a name="t_vector">Vector Type</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1933
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1934<div class="doc_text">
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1935
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1936<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1937<p>A vector type is a simple derived type that represents a vector of elements.
1938 Vector types are used when multiple primitive data are operated in parallel
1939 using a single instruction (SIMD). A vector type requires a size (number of
Duncan Sands31c0e0e2009-11-27 13:38:03 +0000[diff] [blame]1940 elements) and an underlying primitive data type. Vector types are considered
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1941 <a href="#t_firstclass">first class</a>.</p>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1942
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1943<h5>Syntax:</h5>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1944<pre>
1945 &lt; &lt;# elements&gt; x &lt;elementtype&gt; &gt;
1946</pre>
1947
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1948<p>The number of elements is a constant integer value; elementtype may be any
1949 integer or floating point type.</p>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1950
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1951<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1952<table class="layout">
1953 <tr class="layout">
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]1954 <td class="left"><tt>&lt;4 x i32&gt;</tt></td>
1955 <td class="left">Vector of 4 32-bit integer values.</td>
1956 </tr>
1957 <tr class="layout">
1958 <td class="left"><tt>&lt;8 x float&gt;</tt></td>
1959 <td class="left">Vector of 8 32-bit floating-point values.</td>
1960 </tr>
1961 <tr class="layout">
1962 <td class="left"><tt>&lt;2 x i64&gt;</tt></td>
1963 <td class="left">Vector of 2 64-bit integer values.</td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1964 </tr>
1965</table>
Dan Gohman142ccc02009-01-24 15:58:40 +0000[diff] [blame]1966
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1967</div>
1968
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1969<!-- _______________________________________________________________________ -->
1970<div class="doc_subsubsection"> <a name="t_opaque">Opaque Type</a> </div>
1971<div class="doc_text">
1972
1973<h5>Overview:</h5>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1974<p>Opaque types are used to represent unknown types in the system. This
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1975 corresponds (for example) to the C notion of a forward declared structure
1976 type. In LLVM, opaque types can eventually be resolved to any type (not just
1977 a structure type).</p>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1978
1979<h5>Syntax:</h5>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1980<pre>
1981 opaque
1982</pre>
1983
1984<h5>Examples:</h5>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1985<table class="layout">
1986 <tr class="layout">
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]1987 <td class="left"><tt>opaque</tt></td>
1988 <td class="left">An opaque type.</td>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1989 </tr>
1990</table>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1991
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1992</div>
1993
Chris Lattnercf7a5842009-02-02 07:32:36 +0000[diff] [blame]1994<!-- ======================================================================= -->
1995<div class="doc_subsection">
1996 <a name="t_uprefs">Type Up-references</a>
1997</div>
1998
1999<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2000
Chris Lattnercf7a5842009-02-02 07:32:36 +0000[diff] [blame]2001<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2002<p>An "up reference" allows you to refer to a lexically enclosing type without
2003 requiring it to have a name. For instance, a structure declaration may
2004 contain a pointer to any of the types it is lexically a member of. Example
2005 of up references (with their equivalent as named type declarations)
2006 include:</p>
Chris Lattnercf7a5842009-02-02 07:32:36 +0000[diff] [blame]2007
2008<pre>
Chris Lattnerbf1d5452009-02-09 10:00:56 +0000[diff] [blame]2009 { \2 * } %x = type { %x* }
Chris Lattnercf7a5842009-02-02 07:32:36 +0000[diff] [blame]2010 { \2 }* %y = type { %y }*
2011 \1* %z = type %z*
2012</pre>
2013
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2014<p>An up reference is needed by the asmprinter for printing out cyclic types
2015 when there is no declared name for a type in the cycle. Because the
2016 asmprinter does not want to print out an infinite type string, it needs a
2017 syntax to handle recursive types that have no names (all names are optional
2018 in llvm IR).</p>
Chris Lattnercf7a5842009-02-02 07:32:36 +0000[diff] [blame]2019
2020<h5>Syntax:</h5>
2021<pre>
2022 \&lt;level&gt;
2023</pre>
2024
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2025<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]2026
2027<h5>Examples:</h5>
Chris Lattnercf7a5842009-02-02 07:32:36 +0000[diff] [blame]2028<table class="layout">
2029 <tr class="layout">
2030 <td class="left"><tt>\1*</tt></td>
2031 <td class="left">Self-referential pointer.</td>
2032 </tr>
2033 <tr class="layout">
2034 <td class="left"><tt>{ { \3*, i8 }, i32 }</tt></td>
2035 <td class="left">Recursive structure where the upref refers to the out-most
2036 structure.</td>
2037 </tr>
2038</table>
Chris Lattnercf7a5842009-02-02 07:32:36 +0000[diff] [blame]2039
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2040</div>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]2041
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2042<!-- *********************************************************************** -->
2043<div class="doc_section"> <a name="constants">Constants</a> </div>
2044<!-- *********************************************************************** -->
2045
2046<div class="doc_text">
2047
2048<p>LLVM has several different basic types of constants. This section describes
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2049 them all and their syntax.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2050
2051</div>
2052
2053<!-- ======================================================================= -->
Reid Spencer8f08d802004-12-09 18:02:53 +0000[diff] [blame]2054<div class="doc_subsection"><a name="simpleconstants">Simple Constants</a></div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2055
2056<div class="doc_text">
2057
2058<dl>
2059 <dt><b>Boolean constants</b></dt>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2060 <dd>The two strings '<tt>true</tt>' and '<tt>false</tt>' are both valid
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]2061 constants of the <tt><a href="#t_integer">i1</a></tt> type.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2062
2063 <dt><b>Integer constants</b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2064 <dd>Standard integers (such as '4') are constants of
2065 the <a href="#t_integer">integer</a> type. Negative numbers may be used
2066 with integer types.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2067
2068 <dt><b>Floating point constants</b></dt>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2069 <dd>Floating point constants use standard decimal notation (e.g. 123.421),
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2070 exponential notation (e.g. 1.23421e+2), or a more precise hexadecimal
2071 notation (see below). The assembler requires the exact decimal value of a
2072 floating-point constant. For example, the assembler accepts 1.25 but
2073 rejects 1.3 because 1.3 is a repeating decimal in binary. Floating point
2074 constants must have a <a href="#t_floating">floating point</a> type. </dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2075
2076 <dt><b>Null pointer constants</b></dt>
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]2077 <dd>The identifier '<tt>null</tt>' is recognized as a null pointer constant
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2078 and must be of <a href="#t_pointer">pointer type</a>.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2079</dl>
2080
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2081<p>The one non-intuitive notation for constants is the hexadecimal form of
2082 floating point constants. For example, the form '<tt>double
2083 0x432ff973cafa8000</tt>' is equivalent to (but harder to read than)
2084 '<tt>double 4.5e+15</tt>'. The only time hexadecimal floating point
2085 constants are required (and the only time that they are generated by the
2086 disassembler) is when a floating point constant must be emitted but it cannot
2087 be represented as a decimal floating point number in a reasonable number of
2088 digits. For example, NaN's, infinities, and other special values are
2089 represented in their IEEE hexadecimal format so that assembly and disassembly
2090 do not cause any bits to change in the constants.</p>
2091
Dale Johannesencd4a3012009-02-11 22:14:51 +0000[diff] [blame]2092<p>When using the hexadecimal form, constants of types float and double are
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2093 represented using the 16-digit form shown above (which matches the IEEE754
2094 representation for double); float values must, however, be exactly
2095 representable as IEE754 single precision. Hexadecimal format is always used
2096 for long double, and there are three forms of long double. The 80-bit format
2097 used by x86 is represented as <tt>0xK</tt> followed by 20 hexadecimal digits.
2098 The 128-bit format used by PowerPC (two adjacent doubles) is represented
2099 by <tt>0xM</tt> followed by 32 hexadecimal digits. The IEEE 128-bit format
2100 is represented by <tt>0xL</tt> followed by 32 hexadecimal digits; no
2101 currently supported target uses this format. Long doubles will only work if
2102 they match the long double format on your target. All hexadecimal formats
2103 are big-endian (sign bit at the left).</p>
2104
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2105</div>
2106
2107<!-- ======================================================================= -->
Chris Lattner361bfcd2009-02-28 18:32:25 +0000[diff] [blame]2108<div class="doc_subsection">
Bill Wendling972b7202009-07-20 02:32:41 +0000[diff] [blame]2109<a name="aggregateconstants"></a> <!-- old anchor -->
2110<a name="complexconstants">Complex Constants</a>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2111</div>
2112
2113<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2114
Chris Lattner361bfcd2009-02-28 18:32:25 +0000[diff] [blame]2115<p>Complex constants are a (potentially recursive) combination of simple
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2116 constants and smaller complex constants.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2117
2118<dl>
2119 <dt><b>Structure constants</b></dt>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2120 <dd>Structure constants are represented with notation similar to structure
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2121 type definitions (a comma separated list of elements, surrounded by braces
2122 (<tt>{}</tt>)). For example: "<tt>{ i32 4, float 17.0, i32* @G }</tt>",
2123 where "<tt>@G</tt>" is declared as "<tt>@G = external global i32</tt>".
2124 Structure constants must have <a href="#t_struct">structure type</a>, and
2125 the number and types of elements must match those specified by the
2126 type.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2127
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]2128 <dt><b>Union constants</b></dt>
2129 <dd>Union constants are represented with notation similar to a structure with
2130 a single element - that is, a single typed element surrounded
2131 by braces (<tt>{}</tt>)). For example: "<tt>{ i32 4 }</tt>". The
2132 <a href="#t_union">union type</a> can be initialized with a single-element
2133 struct as long as the type of the struct element matches the type of
2134 one of the union members.</dd>
2135
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2136 <dt><b>Array constants</b></dt>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2137 <dd>Array constants are represented with notation similar to array type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2138 definitions (a comma separated list of elements, surrounded by square
2139 brackets (<tt>[]</tt>)). For example: "<tt>[ i32 42, i32 11, i32 74
2140 ]</tt>". Array constants must have <a href="#t_array">array type</a>, and
2141 the number and types of elements must match those specified by the
2142 type.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2143
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]2144 <dt><b>Vector constants</b></dt>
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]2145 <dd>Vector constants are represented with notation similar to vector type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2146 definitions (a comma separated list of elements, surrounded by
2147 less-than/greater-than's (<tt>&lt;&gt;</tt>)). For example: "<tt>&lt; i32
2148 42, i32 11, i32 74, i32 100 &gt;</tt>". Vector constants must
2149 have <a href="#t_vector">vector type</a>, and the number and types of
2150 elements must match those specified by the type.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2151
2152 <dt><b>Zero initialization</b></dt>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2153 <dd>The string '<tt>zeroinitializer</tt>' can be used to zero initialize a
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]2154 value to zero of <em>any</em> type, including scalar and
2155 <a href="#t_aggregate">aggregate</a> types.
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2156 This is often used to avoid having to print large zero initializers
2157 (e.g. for large arrays) and is always exactly equivalent to using explicit
2158 zero initializers.</dd>
Nick Lewycky49f89192009-04-04 07:22:01 +0000[diff] [blame]2159
2160 <dt><b>Metadata node</b></dt>
Nick Lewycky8e2c4f42009-05-30 16:08:30 +0000[diff] [blame]2161 <dd>A metadata node is a structure-like constant with
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2162 <a href="#t_metadata">metadata type</a>. For example: "<tt>metadata !{
2163 i32 0, metadata !"test" }</tt>". Unlike other constants that are meant to
2164 be interpreted as part of the instruction stream, metadata is a place to
2165 attach additional information such as debug info.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2166</dl>
2167
2168</div>
2169
2170<!-- ======================================================================= -->
2171<div class="doc_subsection">
2172 <a name="globalconstants">Global Variable and Function Addresses</a>
2173</div>
2174
2175<div class="doc_text">
2176
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2177<p>The addresses of <a href="#globalvars">global variables</a>
2178 and <a href="#functionstructure">functions</a> are always implicitly valid
2179 (link-time) constants. These constants are explicitly referenced when
2180 the <a href="#identifiers">identifier for the global</a> is used and always
2181 have <a href="#t_pointer">pointer</a> type. For example, the following is a
2182 legal LLVM file:</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2183
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2184<pre class="doc_code">
Chris Lattner00538a12007-06-06 18:28:13 +0000[diff] [blame]2185@X = global i32 17
2186@Y = global i32 42
2187@Z = global [2 x i32*] [ i32* @X, i32* @Y ]
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2188</pre>
2189
2190</div>
2191
2192<!-- ======================================================================= -->
Reid Spencer641f5c92004-12-09 18:13:12 +0000[diff] [blame]2193<div class="doc_subsection"><a name="undefvalues">Undefined Values</a></div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2194<div class="doc_text">
2195
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2196<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]2197 indicates that the user of the value may receive an unspecified bit-pattern.
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2198 Undefined values may be of any type (other than label or void) and be used
2199 anywhere a constant is permitted.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2200
Chris Lattner92ada5d2009-09-11 01:49:31 +0000[diff] [blame]2201<p>Undefined values are useful because they indicate to the compiler that the
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2202 program is well defined no matter what value is used. This gives the
2203 compiler more freedom to optimize. Here are some examples of (potentially
2204 surprising) transformations that are valid (in pseudo IR):</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2205
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2206
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2207<pre class="doc_code">
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2208 %A = add %X, undef
2209 %B = sub %X, undef
2210 %C = xor %X, undef
2211Safe:
2212 %A = undef
2213 %B = undef
2214 %C = undef
2215</pre>
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2216
2217<p>This is safe because all of the output bits are affected by the undef bits.
2218Any output bit can have a zero or one depending on the input bits.</p>
2219
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2220<pre class="doc_code">
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2221 %A = or %X, undef
2222 %B = and %X, undef
2223Safe:
2224 %A = -1
2225 %B = 0
2226Unsafe:
2227 %A = undef
2228 %B = undef
2229</pre>
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2230
2231<p>These logical operations have bits that are not always affected by the input.
2232For example, if "%X" has a zero bit, then the output of the 'and' operation will
2233always be a zero, no matter what the corresponding bit from the undef is. As
Chris Lattner92ada5d2009-09-11 01:49:31 +0000[diff] [blame]2234such, it is unsafe to optimize or assume that the result of the and is undef.
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]2235However, it is safe to assume that all bits of the undef could be 0, and
2236optimize the and to 0. Likewise, it is safe to assume that all the bits of
2237the undef operand to the or could be set, allowing the or to be folded to
Chris Lattner92ada5d2009-09-11 01:49:31 +0000[diff] [blame]2238-1.</p>
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2239
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2240<pre class="doc_code">
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2241 %A = select undef, %X, %Y
2242 %B = select undef, 42, %Y
2243 %C = select %X, %Y, undef
2244Safe:
2245 %A = %X (or %Y)
2246 %B = 42 (or %Y)
2247 %C = %Y
2248Unsafe:
2249 %A = undef
2250 %B = undef
2251 %C = undef
2252</pre>
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2253
2254<p>This set of examples show that undefined select (and conditional branch)
2255conditions can go "either way" but they have to come from one of the two
2256operands. In the %A example, if %X and %Y were both known to have a clear low
2257bit, then %A would have to have a cleared low bit. However, in the %C example,
2258the optimizer is allowed to assume that the undef operand could be the same as
2259%Y, allowing the whole select to be eliminated.</p>
2260
2261
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2262<pre class="doc_code">
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2263 %A = xor undef, undef
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]2264
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2265 %B = undef
2266 %C = xor %B, %B
2267
2268 %D = undef
2269 %E = icmp lt %D, 4
2270 %F = icmp gte %D, 4
2271
2272Safe:
2273 %A = undef
2274 %B = undef
2275 %C = undef
2276 %D = undef
2277 %E = undef
2278 %F = undef
2279</pre>
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2280
2281<p>This example points out that two undef operands are not necessarily the same.
2282This can be surprising to people (and also matches C semantics) where they
2283assume that "X^X" is always zero, even if X is undef. This isn't true for a
2284number of reasons, but the short answer is that an undef "variable" can
2285arbitrarily change its value over its "live range". This is true because the
2286"variable" doesn't actually <em>have a live range</em>. Instead, the value is
2287logically read from arbitrary registers that happen to be around when needed,
Benjamin Kramer0f420382009-10-12 14:46:08 +0000[diff] [blame]2288so the value is not necessarily consistent over time. In fact, %A and %C need
Chris Lattner6760e542009-09-08 15:13:16 +0000[diff] [blame]2289to have the same semantics or the core LLVM "replace all uses with" concept
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2290would not hold.</p>
Chris Lattnera34a7182009-09-07 23:33:52 +0000[diff] [blame]2291
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2292<pre class="doc_code">
Chris Lattnera34a7182009-09-07 23:33:52 +0000[diff] [blame]2293 %A = fdiv undef, %X
2294 %B = fdiv %X, undef
2295Safe:
2296 %A = undef
2297b: unreachable
2298</pre>
Chris Lattnera34a7182009-09-07 23:33:52 +0000[diff] [blame]2299
2300<p>These examples show the crucial difference between an <em>undefined
2301value</em> and <em>undefined behavior</em>. An undefined value (like undef) is
2302allowed to have an arbitrary bit-pattern. This means that the %A operation
2303can be constant folded to undef because the undef could be an SNaN, and fdiv is
2304not (currently) defined on SNaN's. However, in the second example, we can make
2305a more aggressive assumption: because the undef is allowed to be an arbitrary
2306value, we are allowed to assume that it could be zero. Since a divide by zero
Chris Lattner10ff0c12009-09-08 19:45:34 +0000[diff] [blame]2307has <em>undefined behavior</em>, we are allowed to assume that the operation
Chris Lattnera34a7182009-09-07 23:33:52 +0000[diff] [blame]2308does not execute at all. This allows us to delete the divide and all code after
2309it: since the undefined operation "can't happen", the optimizer can assume that
2310it occurs in dead code.
2311</p>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]2312
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2313<pre class="doc_code">
Chris Lattnera34a7182009-09-07 23:33:52 +0000[diff] [blame]2314a: store undef -> %X
2315b: store %X -> undef
2316Safe:
2317a: &lt;deleted&gt;
2318b: unreachable
2319</pre>
Chris Lattnera34a7182009-09-07 23:33:52 +0000[diff] [blame]2320
2321<p>These examples reiterate the fdiv example: a store "of" an undefined value
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]2322can be assumed to not have any effect: we can assume that the value is
Chris Lattnera34a7182009-09-07 23:33:52 +0000[diff] [blame]2323overwritten with bits that happen to match what was already there. However, a
2324store "to" an undefined location could clobber arbitrary memory, therefore, it
2325has undefined behavior.</p>
2326
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2327</div>
2328
2329<!-- ======================================================================= -->
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]2330<div class="doc_subsection"><a name="trapvalues">Trap Values</a></div>
2331<div class="doc_text">
2332
Dan Gohmanb2a709b2010-04-26 20:21:21 +0000[diff] [blame]2333<p>Trap values are similar to <a href="#undefvalues">undef values</a>, however
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]2334 instead of representing an unspecified bit pattern, they represent the
2335 fact that an instruction or constant expression which cannot evoke side
2336 effects has nevertheless detected a condition which results in undefined
Dan Gohmanb2a709b2010-04-26 20:21:21 +0000[diff] [blame]2337 behavior.</p>
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]2338
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2339<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]2340 only exist when produced by operations such as
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2341 <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]2342
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2343<p>Trap value behavior is defined in terms of value <i>dependence</i>:</p>
Dan Gohmanb8b85c12010-04-26 23:36:52 +0000[diff] [blame]2344
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2345<ul>
2346<li>Values other than <a href="#i_phi"><tt>phi</tt></a> nodes depend on
2347 their operands.</li>
2348
2349<li><a href="#i_phi"><tt>Phi</tt></a> nodes depend on the operand corresponding
2350 to their dynamic predecessor basic block.</li>
2351
2352<li>Function arguments depend on the corresponding actual argument values in
2353 the dynamic callers of their functions.</li>
2354
2355<li><a href="#i_call"><tt>Call</tt></a> instructions depend on the
2356 <a href="#i_ret"><tt>ret</tt></a> instructions that dynamically transfer
2357 control back to them.</li>
2358
Dan Gohman7292a752010-05-03 14:55:22 +0000[diff] [blame]2359<li><a href="#i_invoke"><tt>Invoke</tt></a> instructions depend on the
2360 <a href="#i_ret"><tt>ret</tt></a>, <a href="#i_unwind"><tt>unwind</tt></a>,
2361 or exception-throwing call instructions that dynamically transfer control
2362 back to them.</li>
2363
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2364<li>Non-volatile loads and stores depend on the most recent stores to all of the
2365 referenced memory addresses, following the order in the IR
2366 (including loads and stores implied by intrinsics such as
2367 <a href="#int_memcpy"><tt>@llvm.memcpy</tt></a>.)</li>
2368
Dan Gohman3513ea52010-05-03 14:59:34 +0000[diff] [blame]2369<!-- TODO: In the case of multiple threads, this only applies if the store
2370 "happens-before" the load or store. -->
Dan Gohmanb8b85c12010-04-26 23:36:52 +0000[diff] [blame]2371
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2372<!-- TODO: floating-point exception state -->
Dan Gohmanb8b85c12010-04-26 23:36:52 +0000[diff] [blame]2373
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2374<li>An instruction with externally visible side effects depends on the most
2375 recent preceding instruction with externally visible side effects, following
Dan Gohman6c858db2010-07-06 15:26:33 +0000[diff] [blame]2376 the order in the IR. (This includes
2377 <a href="#volatile">volatile operations</a>.)</li>
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]2378
Dan Gohman7292a752010-05-03 14:55:22 +0000[diff] [blame]2379<li>An instruction <i>control-depends</i> on a
2380 <a href="#terminators">terminator instruction</a>
2381 if the terminator instruction has multiple successors and the instruction
2382 is always executed when control transfers to one of the successors, and
2383 may not be executed when control is transfered to another.</li>
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2384
2385<li>Dependence is transitive.</li>
2386
2387</ul>
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2388
2389<p>Whenever a trap value is generated, all values which depend on it evaluate
2390 to trap. If they have side effects, the evoke their side effects as if each
2391 operand with a trap value were undef. If they have externally-visible side
2392 effects, the behavior is undefined.</p>
2393
2394<p>Here are some examples:</p>
Dan Gohman48a25882010-04-26 20:54:53 +0000[diff] [blame]2395
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2396<pre class="doc_code">
Dan Gohmanb8b85c12010-04-26 23:36:52 +0000[diff] [blame]2397entry:
2398 %trap = sub nuw i32 0, 1 ; Results in a trap value.
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2399 %still_trap = and i32 %trap, 0 ; Whereas (and i32 undef, 0) would return 0.
2400 %trap_yet_again = getelementptr i32* @h, i32 %still_trap
2401 store i32 0, i32* %trap_yet_again ; undefined behavior
2402
2403 store i32 %trap, i32* @g ; Trap value conceptually stored to memory.
2404 %trap2 = load i32* @g ; Returns a trap value, not just undef.
2405
2406 volatile store i32 %trap, i32* @g ; External observation; undefined behavior.
2407
2408 %narrowaddr = bitcast i32* @g to i16*
2409 %wideaddr = bitcast i32* @g to i64*
2410 %trap3 = load 16* %narrowaddr ; Returns a trap value.
2411 %trap4 = load i64* %widaddr ; Returns a trap value.
2412
2413 %cmp = icmp i32 slt %trap, 0 ; Returns a trap value.
Dan Gohmanb8b85c12010-04-26 23:36:52 +0000[diff] [blame]2414 %br i1 %cmp, %true, %end ; Branch to either destination.
2415
2416true:
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2417 volatile store i32 0, i32* @g ; This is control-dependent on %cmp, so
2418 ; it has undefined behavior.
Dan Gohmanb8b85c12010-04-26 23:36:52 +0000[diff] [blame]2419 br label %end
2420
2421end:
2422 %p = phi i32 [ 0, %entry ], [ 1, %true ]
2423 ; Both edges into this PHI are
2424 ; control-dependent on %cmp, so this
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2425 ; always results in a trap value.
Dan Gohmanb8b85c12010-04-26 23:36:52 +0000[diff] [blame]2426
2427 volatile store i32 0, i32* @g ; %end is control-equivalent to %entry
2428 ; so this is defined (ignoring earlier
2429 ; undefined behavior in this example).
Dan Gohmanb8b85c12010-04-26 23:36:52 +0000[diff] [blame]2430</pre>
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]2431
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]2432</div>
2433
2434<!-- ======================================================================= -->
Chris Lattner2bfd3202009-10-27 21:19:13 +0000[diff] [blame]2435<div class="doc_subsection"><a name="blockaddress">Addresses of Basic
2436 Blocks</a></div>
Chris Lattnere4801f72009-10-27 21:01:34 +0000[diff] [blame]2437<div class="doc_text">
2438
Chris Lattneraa99c942009-11-01 01:27:45 +0000[diff] [blame]2439<p><b><tt>blockaddress(@function, %block)</tt></b></p>
Chris Lattnere4801f72009-10-27 21:01:34 +0000[diff] [blame]2440
2441<p>The '<tt>blockaddress</tt>' constant computes the address of the specified
Chris Lattner5c5f0ac2009-10-27 21:49:40 +0000[diff] [blame]2442 basic block in the specified function, and always has an i8* type. Taking
Chris Lattneraa99c942009-11-01 01:27:45 +0000[diff] [blame]2443 the address of the entry block is illegal.</p>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]2444
Chris Lattnere4801f72009-10-27 21:01:34 +0000[diff] [blame]2445<p>This value only has defined behavior when used as an operand to the
Chris Lattnerd04cb6d2009-10-28 00:19:10 +0000[diff] [blame]2446 '<a href="#i_indirectbr"><tt>indirectbr</tt></a>' instruction or for comparisons
Chris Lattnere4801f72009-10-27 21:01:34 +0000[diff] [blame]2447 against null. Pointer equality tests between labels addresses is undefined
2448 behavior - though, again, comparison against null is ok, and no label is
Chris Lattner2bfd3202009-10-27 21:19:13 +0000[diff] [blame]2449 equal to the null pointer. This may also be passed around as an opaque
2450 pointer sized value as long as the bits are not inspected. This allows
Chris Lattnerda37b302009-10-27 21:44:20 +0000[diff] [blame]2451 <tt>ptrtoint</tt> and arithmetic to be performed on these values so long as
Chris Lattnerd04cb6d2009-10-28 00:19:10 +0000[diff] [blame]2452 the original value is reconstituted before the <tt>indirectbr</tt>.</p>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]2453
Chris Lattner2bfd3202009-10-27 21:19:13 +0000[diff] [blame]2454<p>Finally, some targets may provide defined semantics when
Chris Lattnere4801f72009-10-27 21:01:34 +0000[diff] [blame]2455 using the value as the operand to an inline assembly, but that is target
2456 specific.
2457 </p>
2458
2459</div>
2460
2461
2462<!-- ======================================================================= -->
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2463<div class="doc_subsection"><a name="constantexprs">Constant Expressions</a>
2464</div>
2465
2466<div class="doc_text">
2467
2468<p>Constant expressions are used to allow expressions involving other constants
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2469 to be used as constants. Constant expressions may be of
2470 any <a href="#t_firstclass">first class</a> type and may involve any LLVM
2471 operation that does not have side effects (e.g. load and call are not
2472 supported). The following is the syntax for constant expressions:</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2473
2474<dl>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2475 <dt><b><tt>trunc (CST to TYPE)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2476 <dd>Truncate a constant to another type. The bit size of CST must be larger
2477 than the bit size of TYPE. Both types must be integers.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2478
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2479 <dt><b><tt>zext (CST to TYPE)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2480 <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]2481 smaller than the bit size of TYPE. Both types must be integers.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2482
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2483 <dt><b><tt>sext (CST to TYPE)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2484 <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]2485 smaller than the bit size of TYPE. Both types must be integers.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2486
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2487 <dt><b><tt>fptrunc (CST to TYPE)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2488 <dd>Truncate a floating point constant to another floating point type. The
2489 size of CST must be larger than the size of TYPE. Both types must be
2490 floating point.</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>fpext (CST to TYPE)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2493 <dd>Floating point extend a constant to another type. The size of CST must be
2494 smaller or equal to the size of TYPE. Both types must be floating
2495 point.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2496
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2497 <dt><b><tt>fptoui (CST to TYPE)</tt></b></dt>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2498 <dd>Convert a floating point constant to the corresponding unsigned integer
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2499 constant. TYPE must be a scalar or vector integer type. CST must be of
2500 scalar or vector floating point type. Both CST and TYPE must be scalars,
2501 or vectors of the same number of elements. If the value won't fit in the
2502 integer type, the results are undefined.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2503
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2504 <dt><b><tt>fptosi (CST to TYPE)</tt></b></dt>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2505 <dd>Convert a floating point constant to the corresponding signed integer
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2506 constant. TYPE must be a scalar or vector integer type. CST must be of
2507 scalar or vector floating point type. Both CST and TYPE must be scalars,
2508 or vectors of the same number of elements. If the value won't fit in the
2509 integer type, the results are undefined.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2510
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2511 <dt><b><tt>uitofp (CST to TYPE)</tt></b></dt>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2512 <dd>Convert an unsigned integer constant to the corresponding floating point
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2513 constant. TYPE must be a scalar or vector floating point type. CST must be
2514 of scalar or vector integer type. Both CST and TYPE must be scalars, or
2515 vectors of the same number of elements. If the value won't fit in the
2516 floating point type, the results are undefined.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2517
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2518 <dt><b><tt>sitofp (CST to TYPE)</tt></b></dt>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2519 <dd>Convert a signed integer constant to the corresponding floating point
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2520 constant. TYPE must be a scalar or vector floating point type. CST must be
2521 of scalar or vector integer type. Both CST and TYPE must be scalars, or
2522 vectors of the same number of elements. If the value won't fit in the
2523 floating point type, the results are undefined.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2524
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2525 <dt><b><tt>ptrtoint (CST to TYPE)</tt></b></dt>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]2526 <dd>Convert a pointer typed constant to the corresponding integer constant
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2527 <tt>TYPE</tt> must be an integer type. <tt>CST</tt> must be of pointer
2528 type. The <tt>CST</tt> value is zero extended, truncated, or unchanged to
2529 make it fit in <tt>TYPE</tt>.</dd>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]2530
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2531 <dt><b><tt>inttoptr (CST to TYPE)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2532 <dd>Convert a integer constant to a pointer constant. TYPE must be a pointer
2533 type. CST must be of integer type. The CST value is zero extended,
2534 truncated, or unchanged to make it fit in a pointer size. This one is
2535 <i>really</i> dangerous!</dd>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]2536
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2537 <dt><b><tt>bitcast (CST to TYPE)</tt></b></dt>
Chris Lattner789dee32009-02-28 18:27:03 +0000[diff] [blame]2538 <dd>Convert a constant, CST, to another TYPE. The constraints of the operands
2539 are the same as those for the <a href="#i_bitcast">bitcast
2540 instruction</a>.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2541
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2542 <dt><b><tt>getelementptr (CSTPTR, IDX0, IDX1, ...)</tt></b></dt>
2543 <dt><b><tt>getelementptr inbounds (CSTPTR, IDX0, IDX1, ...)</tt></b></dt>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2544 <dd>Perform the <a href="#i_getelementptr">getelementptr operation</a> on
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2545 constants. As with the <a href="#i_getelementptr">getelementptr</a>
2546 instruction, the index list may have zero or more indexes, which are
2547 required to make sense for the type of "CSTPTR".</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2548
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2549 <dt><b><tt>select (COND, VAL1, VAL2)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2550 <dd>Perform the <a href="#i_select">select operation</a> on constants.</dd>
Reid Spencer9965ee72006-12-04 19:23:19 +0000[diff] [blame]2551
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2552 <dt><b><tt>icmp COND (VAL1, VAL2)</tt></b></dt>
Reid Spencer9965ee72006-12-04 19:23:19 +0000[diff] [blame]2553 <dd>Performs the <a href="#i_icmp">icmp operation</a> on constants.</dd>
2554
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2555 <dt><b><tt>fcmp COND (VAL1, VAL2)</tt></b></dt>
Reid Spencer9965ee72006-12-04 19:23:19 +0000[diff] [blame]2556 <dd>Performs the <a href="#i_fcmp">fcmp operation</a> on constants.</dd>
Robert Bocchino7e97a6d2006-01-10 19:31:34 +0000[diff] [blame]2557
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2558 <dt><b><tt>extractelement (VAL, IDX)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2559 <dd>Perform the <a href="#i_extractelement">extractelement operation</a> on
2560 constants.</dd>
Robert Bocchino7e97a6d2006-01-10 19:31:34 +0000[diff] [blame]2561
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2562 <dt><b><tt>insertelement (VAL, ELT, IDX)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2563 <dd>Perform the <a href="#i_insertelement">insertelement operation</a> on
2564 constants.</dd>
Chris Lattner016a0e52006-04-08 00:13:41 +0000[diff] [blame]2565
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2566 <dt><b><tt>shufflevector (VEC1, VEC2, IDXMASK)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2567 <dd>Perform the <a href="#i_shufflevector">shufflevector operation</a> on
2568 constants.</dd>
Chris Lattner016a0e52006-04-08 00:13:41 +0000[diff] [blame]2569
Nick Lewycky9ab9a7f2010-05-29 06:44:15 +0000[diff] [blame]2570 <dt><b><tt>extractvalue (VAL, IDX0, IDX1, ...)</tt></b></dt>
2571 <dd>Perform the <a href="#i_extractvalue">extractvalue operation</a> on
2572 constants. The index list is interpreted in a similar manner as indices in
2573 a '<a href="#i_getelementptr">getelementptr</a>' operation. At least one
2574 index value must be specified.</dd>
2575
2576 <dt><b><tt>insertvalue (VAL, ELT, IDX0, IDX1, ...)</tt></b></dt>
2577 <dd>Perform the <a href="#i_insertvalue">insertvalue operation</a> on
2578 constants. The index list is interpreted in a similar manner as indices in
2579 a '<a href="#i_getelementptr">getelementptr</a>' operation. At least one
2580 index value must be specified.</dd>
2581
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2582 <dt><b><tt>OPCODE (LHS, RHS)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2583 <dd>Perform the specified operation of the LHS and RHS constants. OPCODE may
2584 be any of the <a href="#binaryops">binary</a>
2585 or <a href="#bitwiseops">bitwise binary</a> operations. The constraints
2586 on operands are the same as those for the corresponding instruction
2587 (e.g. no bitwise operations on floating point values are allowed).</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2588</dl>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2589
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2590</div>
Chris Lattnerb1652612004-03-08 16:49:10 +0000[diff] [blame]2591
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2592<!-- *********************************************************************** -->
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2593<div class="doc_section"> <a name="othervalues">Other Values</a> </div>
2594<!-- *********************************************************************** -->
2595
2596<!-- ======================================================================= -->
2597<div class="doc_subsection">
2598<a name="inlineasm">Inline Assembler Expressions</a>
2599</div>
2600
2601<div class="doc_text">
2602
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2603<p>LLVM supports inline assembler expressions (as opposed
2604 to <a href="#moduleasm"> Module-Level Inline Assembly</a>) through the use of
2605 a special value. This value represents the inline assembler as a string
2606 (containing the instructions to emit), a list of operand constraints (stored
Dale Johannesen63c94fe2009-10-13 21:56:55 +0000[diff] [blame]2607 as a string), a flag that indicates whether or not the inline asm
Dale Johannesen1cfb9582009-10-21 23:28:00 +0000[diff] [blame]2608 expression has side effects, and a flag indicating whether the function
2609 containing the asm needs to align its stack conservatively. An example
2610 inline assembler expression is:</p>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2611
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2612<pre class="doc_code">
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2613i32 (i32) asm "bswap $0", "=r,r"
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2614</pre>
2615
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2616<p>Inline assembler expressions may <b>only</b> be used as the callee operand of
2617 a <a href="#i_call"><tt>call</tt> instruction</a>. Thus, typically we
2618 have:</p>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2619
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2620<pre class="doc_code">
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2621%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]2622</pre>
2623
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2624<p>Inline asms with side effects not visible in the constraint list must be
2625 marked as having side effects. This is done through the use of the
2626 '<tt>sideeffect</tt>' keyword, like so:</p>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2627
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2628<pre class="doc_code">
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2629call void asm sideeffect "eieio", ""()
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2630</pre>
2631
Dale Johannesen1cfb9582009-10-21 23:28:00 +0000[diff] [blame]2632<p>In some cases inline asms will contain code that will not work unless the
2633 stack is aligned in some way, such as calls or SSE instructions on x86,
2634 yet will not contain code that does that alignment within the asm.
2635 The compiler should make conservative assumptions about what the asm might
2636 contain and should generate its usual stack alignment code in the prologue
2637 if the '<tt>alignstack</tt>' keyword is present:</p>
Dale Johannesen63c94fe2009-10-13 21:56:55 +0000[diff] [blame]2638
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2639<pre class="doc_code">
Dale Johannesen1cfb9582009-10-21 23:28:00 +0000[diff] [blame]2640call void asm alignstack "eieio", ""()
Dale Johannesen63c94fe2009-10-13 21:56:55 +0000[diff] [blame]2641</pre>
Dale Johannesen63c94fe2009-10-13 21:56:55 +0000[diff] [blame]2642
2643<p>If both keywords appear the '<tt>sideeffect</tt>' keyword must come
2644 first.</p>
2645
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2646<p>TODO: The format of the asm and constraints string still need to be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2647 documented here. Constraints on what can be done (e.g. duplication, moving,
2648 etc need to be documented). This is probably best done by reference to
2649 another document that covers inline asm from a holistic perspective.</p>
Chris Lattner51065562010-04-07 05:38:05 +0000[diff] [blame]2650</div>
2651
2652<div class="doc_subsubsection">
2653<a name="inlineasm_md">Inline Asm Metadata</a>
2654</div>
2655
2656<div class="doc_text">
2657
2658<p>The call instructions that wrap inline asm nodes may have a "!srcloc" MDNode
2659 attached to it that contains a constant integer. If present, the code
2660 generator will use the integer as the location cookie value when report
2661 errors through the LLVMContext error reporting mechanisms. This allows a
Dan Gohman61110ae2010-04-28 00:36:01 +0000[diff] [blame]2662 front-end to correlate backend errors that occur with inline asm back to the
Chris Lattner51065562010-04-07 05:38:05 +0000[diff] [blame]2663 source code that produced it. For example:</p>
2664
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2665<pre class="doc_code">
Chris Lattner51065562010-04-07 05:38:05 +0000[diff] [blame]2666call void asm sideeffect "something bad", ""()<b>, !srcloc !42</b>
2667...
2668!42 = !{ i32 1234567 }
2669</pre>
Chris Lattner51065562010-04-07 05:38:05 +0000[diff] [blame]2670
2671<p>It is up to the front-end to make sense of the magic numbers it places in the
2672 IR.</p>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2673
2674</div>
2675
Chris Lattnerc2f8f162010-01-15 21:50:19 +0000[diff] [blame]2676<!-- ======================================================================= -->
2677<div class="doc_subsection"><a name="metadata">Metadata Nodes and Metadata
2678 Strings</a>
2679</div>
2680
2681<div class="doc_text">
2682
2683<p>LLVM IR allows metadata to be attached to instructions in the program that
2684 can convey extra information about the code to the optimizers and code
2685 generator. One example application of metadata is source-level debug
2686 information. There are two metadata primitives: strings and nodes. All
2687 metadata has the <tt>metadata</tt> type and is identified in syntax by a
2688 preceding exclamation point ('<tt>!</tt>').</p>
2689
2690<p>A metadata string is a string surrounded by double quotes. It can contain
2691 any character by escaping non-printable characters with "\xx" where "xx" is
2692 the two digit hex code. For example: "<tt>!"test\00"</tt>".</p>
2693
2694<p>Metadata nodes are represented with notation similar to structure constants
2695 (a comma separated list of elements, surrounded by braces and preceded by an
2696 exclamation point). For example: "<tt>!{ metadata !"test\00", i32
2697 10}</tt>". Metadata nodes can have any values as their operand.</p>
2698
2699<p>A <a href="#namedmetadatastructure">named metadata</a> is a collection of
2700 metadata nodes, which can be looked up in the module symbol table. For
2701 example: "<tt>!foo = metadata !{!4, !3}</tt>".
2702
Devang Patel9984bd62010-03-04 23:44:48 +0000[diff] [blame]2703<p>Metadata can be used as function arguments. Here <tt>llvm.dbg.value</tt>
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2704 function is using two metadata arguments.</p>
Devang Patel9984bd62010-03-04 23:44:48 +0000[diff] [blame]2705
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2706 <pre class="doc_code">
Devang Patel9984bd62010-03-04 23:44:48 +0000[diff] [blame]2707 call void @llvm.dbg.value(metadata !24, i64 0, metadata !25)
2708 </pre>
Devang Patel9984bd62010-03-04 23:44:48 +0000[diff] [blame]2709
2710<p>Metadata can be attached with an instruction. Here metadata <tt>!21</tt> is
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2711 attached with <tt>add</tt> instruction using <tt>!dbg</tt> identifier.</p>
Devang Patel9984bd62010-03-04 23:44:48 +0000[diff] [blame]2712
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2713 <pre class="doc_code">
Devang Patel9984bd62010-03-04 23:44:48 +0000[diff] [blame]2714 %indvar.next = add i64 %indvar, 1, !dbg !21
2715 </pre>
Chris Lattnerc2f8f162010-01-15 21:50:19 +0000[diff] [blame]2716</div>
2717
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]2718
2719<!-- *********************************************************************** -->
2720<div class="doc_section">
2721 <a name="intrinsic_globals">Intrinsic Global Variables</a>
2722</div>
2723<!-- *********************************************************************** -->
2724
2725<p>LLVM has a number of "magic" global variables that contain data that affect
2726code generation or other IR semantics. These are documented here. All globals
Chris Lattner58f9bb22009-07-20 06:14:25 +0000[diff] [blame]2727of this sort should have a section specified as "<tt>llvm.metadata</tt>". This
2728section and all globals that start with "<tt>llvm.</tt>" are reserved for use
2729by LLVM.</p>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]2730
2731<!-- ======================================================================= -->
2732<div class="doc_subsection">
2733<a name="intg_used">The '<tt>llvm.used</tt>' Global Variable</a>
2734</div>
2735
2736<div class="doc_text">
2737
2738<p>The <tt>@llvm.used</tt> global is an array with i8* element type which has <a
2739href="#linkage_appending">appending linkage</a>. This array contains a list of
2740pointers to global variables and functions which may optionally have a pointer
2741cast formed of bitcast or getelementptr. For example, a legal use of it is:</p>
2742
2743<pre>
2744 @X = global i8 4
2745 @Y = global i32 123
2746
2747 @llvm.used = appending global [2 x i8*] [
2748 i8* @X,
2749 i8* bitcast (i32* @Y to i8*)
2750 ], section "llvm.metadata"
2751</pre>
2752
2753<p>If a global variable appears in the <tt>@llvm.used</tt> list, then the
2754compiler, assembler, and linker are required to treat the symbol as if there is
2755a reference to the global that it cannot see. For example, if a variable has
2756internal linkage and no references other than that from the <tt>@llvm.used</tt>
2757list, it cannot be deleted. This is commonly used to represent references from
2758inline asms and other things the compiler cannot "see", and corresponds to
2759"attribute((used))" in GNU C.</p>
2760
2761<p>On some targets, the code generator must emit a directive to the assembler or
2762object file to prevent the assembler and linker from molesting the symbol.</p>
2763
2764</div>
2765
2766<!-- ======================================================================= -->
2767<div class="doc_subsection">
Chris Lattner58f9bb22009-07-20 06:14:25 +0000[diff] [blame]2768<a name="intg_compiler_used">The '<tt>llvm.compiler.used</tt>' Global Variable</a>
2769</div>
2770
2771<div class="doc_text">
2772
2773<p>The <tt>@llvm.compiler.used</tt> directive is the same as the
2774<tt>@llvm.used</tt> directive, except that it only prevents the compiler from
2775touching the symbol. On targets that support it, this allows an intelligent
2776linker to optimize references to the symbol without being impeded as it would be
2777by <tt>@llvm.used</tt>.</p>
2778
2779<p>This is a rare construct that should only be used in rare circumstances, and
2780should not be exposed to source languages.</p>
2781
2782</div>
2783
2784<!-- ======================================================================= -->
2785<div class="doc_subsection">
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]2786<a name="intg_global_ctors">The '<tt>llvm.global_ctors</tt>' Global Variable</a>
2787</div>
2788
2789<div class="doc_text">
David Chisnalla9d4a6f2010-04-30 19:23:49 +0000[diff] [blame]2790<pre>
2791%0 = type { i32, void ()* }
David Chisnallb492b812010-04-30 19:27:35 +0000[diff] [blame]2792@llvm.global_ctors = appending global [1 x %0] [%0 { i32 65535, void ()* @ctor }]
David Chisnalla9d4a6f2010-04-30 19:23:49 +0000[diff] [blame]2793</pre>
2794<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.
2795</p>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]2796
2797</div>
2798
2799<!-- ======================================================================= -->
2800<div class="doc_subsection">
2801<a name="intg_global_dtors">The '<tt>llvm.global_dtors</tt>' Global Variable</a>
2802</div>
2803
2804<div class="doc_text">
David Chisnalla9d4a6f2010-04-30 19:23:49 +0000[diff] [blame]2805<pre>
2806%0 = type { i32, void ()* }
David Chisnallb492b812010-04-30 19:27:35 +0000[diff] [blame]2807@llvm.global_dtors = appending global [1 x %0] [%0 { i32 65535, void ()* @dtor }]
David Chisnalla9d4a6f2010-04-30 19:23:49 +0000[diff] [blame]2808</pre>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]2809
David Chisnalla9d4a6f2010-04-30 19:23:49 +0000[diff] [blame]2810<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.
2811</p>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]2812
2813</div>
2814
2815
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2816<!-- *********************************************************************** -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2817<div class="doc_section"> <a name="instref">Instruction Reference</a> </div>
2818<!-- *********************************************************************** -->
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2819
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2820<div class="doc_text">
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2821
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2822<p>The LLVM instruction set consists of several different classifications of
2823 instructions: <a href="#terminators">terminator
2824 instructions</a>, <a href="#binaryops">binary instructions</a>,
2825 <a href="#bitwiseops">bitwise binary instructions</a>,
2826 <a href="#memoryops">memory instructions</a>, and
2827 <a href="#otherops">other instructions</a>.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2828
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2829</div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2830
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2831<!-- ======================================================================= -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2832<div class="doc_subsection"> <a name="terminators">Terminator
2833Instructions</a> </div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2834
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2835<div class="doc_text">
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2836
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2837<p>As mentioned <a href="#functionstructure">previously</a>, every basic block
2838 in a program ends with a "Terminator" instruction, which indicates which
2839 block should be executed after the current block is finished. These
2840 terminator instructions typically yield a '<tt>void</tt>' value: they produce
2841 control flow, not values (the one exception being the
2842 '<a href="#i_invoke"><tt>invoke</tt></a>' instruction).</p>
2843
Duncan Sands626b0242010-04-15 20:35:54 +0000[diff] [blame]2844<p>There are seven different terminator instructions: the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2845 '<a href="#i_ret"><tt>ret</tt></a>' instruction, the
2846 '<a href="#i_br"><tt>br</tt></a>' instruction, the
2847 '<a href="#i_switch"><tt>switch</tt></a>' instruction, the
Bill Wendling33fef7e2009-11-02 00:25:26 +0000[diff] [blame]2848 '<a href="#i_indirectbr">'<tt>indirectbr</tt></a>' Instruction, the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2849 '<a href="#i_invoke"><tt>invoke</tt></a>' instruction, the
2850 '<a href="#i_unwind"><tt>unwind</tt></a>' instruction, and the
2851 '<a href="#i_unreachable"><tt>unreachable</tt></a>' instruction.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2852
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2853</div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2854
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2855<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2856<div class="doc_subsubsection"> <a name="i_ret">'<tt>ret</tt>'
2857Instruction</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2858
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2859<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2860
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2861<h5>Syntax:</h5>
Dan Gohmancc3132e2008-10-04 19:00:07 +0000[diff] [blame]2862<pre>
2863 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]2864 ret void <i>; Return from void function</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2865</pre>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]2866
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2867<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2868<p>The '<tt>ret</tt>' instruction is used to return control flow (and optionally
2869 a value) from a function back to the caller.</p>
2870
2871<p>There are two forms of the '<tt>ret</tt>' instruction: one that returns a
2872 value and then causes control flow, and one that just causes control flow to
2873 occur.</p>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]2874
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2875<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2876<p>The '<tt>ret</tt>' instruction optionally accepts a single argument, the
2877 return value. The type of the return value must be a
2878 '<a href="#t_firstclass">first class</a>' type.</p>
Dan Gohmancc3132e2008-10-04 19:00:07 +0000[diff] [blame]2879
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2880<p>A function is not <a href="#wellformed">well formed</a> if it it has a
2881 non-void return type and contains a '<tt>ret</tt>' instruction with no return
2882 value or a return value with a type that does not match its type, or if it
2883 has a void return type and contains a '<tt>ret</tt>' instruction with a
2884 return value.</p>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]2885
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2886<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2887<p>When the '<tt>ret</tt>' instruction is executed, control flow returns back to
2888 the calling function's context. If the caller is a
2889 "<a href="#i_call"><tt>call</tt></a>" instruction, execution continues at the
2890 instruction after the call. If the caller was an
2891 "<a href="#i_invoke"><tt>invoke</tt></a>" instruction, execution continues at
2892 the beginning of the "normal" destination block. If the instruction returns
2893 a value, that value shall set the call or invoke instruction's return
2894 value.</p>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]2895
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2896<h5>Example:</h5>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]2897<pre>
2898 ret i32 5 <i>; Return an integer value of 5</i>
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]2899 ret void <i>; Return from a void function</i>
Bill Wendling050ee8f2009-02-28 22:12:54 +0000[diff] [blame]2900 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]2901</pre>
Dan Gohman3065b612009-01-12 23:12:39 +0000[diff] [blame]2902
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2903</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2904<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2905<div class="doc_subsubsection"> <a name="i_br">'<tt>br</tt>' Instruction</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2906
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2907<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2908
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2909<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2910<pre>
2911 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]2912</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2913
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2914<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2915<p>The '<tt>br</tt>' instruction is used to cause control flow to transfer to a
2916 different basic block in the current function. There are two forms of this
2917 instruction, corresponding to a conditional branch and an unconditional
2918 branch.</p>
2919
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2920<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2921<p>The conditional branch form of the '<tt>br</tt>' instruction takes a single
2922 '<tt>i1</tt>' value and two '<tt>label</tt>' values. The unconditional form
2923 of the '<tt>br</tt>' instruction takes a single '<tt>label</tt>' value as a
2924 target.</p>
2925
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2926<h5>Semantics:</h5>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]2927<p>Upon execution of a conditional '<tt>br</tt>' instruction, the '<tt>i1</tt>'
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2928 argument is evaluated. If the value is <tt>true</tt>, control flows to the
2929 '<tt>iftrue</tt>' <tt>label</tt> argument. If "cond" is <tt>false</tt>,
2930 control flows to the '<tt>iffalse</tt>' <tt>label</tt> argument.</p>
2931
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2932<h5>Example:</h5>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]2933<pre>
2934Test:
2935 %cond = <a href="#i_icmp">icmp</a> eq i32 %a, %b
2936 br i1 %cond, label %IfEqual, label %IfUnequal
2937IfEqual:
2938 <a href="#i_ret">ret</a> i32 1
2939IfUnequal:
2940 <a href="#i_ret">ret</a> i32 0
2941</pre>
2942
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2943</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2944
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2945<!-- _______________________________________________________________________ -->
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2946<div class="doc_subsubsection">
2947 <a name="i_switch">'<tt>switch</tt>' Instruction</a>
2948</div>
2949
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2950<div class="doc_text">
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2951
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2952<h5>Syntax:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2953<pre>
2954 switch &lt;intty&gt; &lt;value&gt;, label &lt;defaultdest&gt; [ &lt;intty&gt; &lt;val&gt;, label &lt;dest&gt; ... ]
2955</pre>
2956
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2957<h5>Overview:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2958<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]2959 several different places. It is a generalization of the '<tt>br</tt>'
2960 instruction, allowing a branch to occur to one of many possible
2961 destinations.</p>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2962
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2963<h5>Arguments:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2964<p>The '<tt>switch</tt>' instruction uses three parameters: an integer
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2965 comparison value '<tt>value</tt>', a default '<tt>label</tt>' destination,
2966 and an array of pairs of comparison value constants and '<tt>label</tt>'s.
2967 The table is not allowed to contain duplicate constant entries.</p>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2968
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2969<h5>Semantics:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2970<p>The <tt>switch</tt> instruction specifies a table of values and
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2971 destinations. When the '<tt>switch</tt>' instruction is executed, this table
2972 is searched for the given value. If the value is found, control flow is
Benjamin Kramer0f420382009-10-12 14:46:08 +0000[diff] [blame]2973 transferred to the corresponding destination; otherwise, control flow is
2974 transferred to the default destination.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2975
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2976<h5>Implementation:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2977<p>Depending on properties of the target machine and the particular
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2978 <tt>switch</tt> instruction, this instruction may be code generated in
2979 different ways. For example, it could be generated as a series of chained
2980 conditional branches or with a lookup table.</p>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2981
2982<h5>Example:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2983<pre>
2984 <i>; Emulate a conditional br instruction</i>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]2985 %Val = <a href="#i_zext">zext</a> i1 %value to i32
Dan Gohman623806e2009-01-04 23:44:43 +0000[diff] [blame]2986 switch i32 %Val, label %truedest [ i32 0, label %falsedest ]
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2987
2988 <i>; Emulate an unconditional br instruction</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2989 switch i32 0, label %dest [ ]
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2990
2991 <i>; Implement a jump table:</i>
Dan Gohman623806e2009-01-04 23:44:43 +0000[diff] [blame]2992 switch i32 %val, label %otherwise [ i32 0, label %onzero
2993 i32 1, label %onone
2994 i32 2, label %ontwo ]
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2995</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2996
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2997</div>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]2998
Chris Lattner3ed871f2009-10-27 19:13:16 +0000[diff] [blame]2999
3000<!-- _______________________________________________________________________ -->
3001<div class="doc_subsubsection">
Chris Lattnerd04cb6d2009-10-28 00:19:10 +0000[diff] [blame]3002 <a name="i_indirectbr">'<tt>indirectbr</tt>' Instruction</a>
Chris Lattner3ed871f2009-10-27 19:13:16 +0000[diff] [blame]3003</div>
3004
3005<div class="doc_text">
3006
3007<h5>Syntax:</h5>
3008<pre>
Chris Lattnerd04cb6d2009-10-28 00:19:10 +0000[diff] [blame]3009 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]3010</pre>
3011
3012<h5>Overview:</h5>
3013
Chris Lattnerd04cb6d2009-10-28 00:19:10 +0000[diff] [blame]3014<p>The '<tt>indirectbr</tt>' instruction implements an indirect branch to a label
Chris Lattner3ed871f2009-10-27 19:13:16 +0000[diff] [blame]3015 within the current function, whose address is specified by
Chris Lattnere4801f72009-10-27 21:01:34 +0000[diff] [blame]3016 "<tt>address</tt>". Address must be derived from a <a
3017 href="#blockaddress">blockaddress</a> constant.</p>
Chris Lattner3ed871f2009-10-27 19:13:16 +0000[diff] [blame]3018
3019<h5>Arguments:</h5>
3020
3021<p>The '<tt>address</tt>' argument is the address of the label to jump to. The
3022 rest of the arguments indicate the full set of possible destinations that the
3023 address may point to. Blocks are allowed to occur multiple times in the
3024 destination list, though this isn't particularly useful.</p>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3025
Chris Lattner3ed871f2009-10-27 19:13:16 +0000[diff] [blame]3026<p>This destination list is required so that dataflow analysis has an accurate
3027 understanding of the CFG.</p>
3028
3029<h5>Semantics:</h5>
3030
3031<p>Control transfers to the block specified in the address argument. All
3032 possible destination blocks must be listed in the label list, otherwise this
3033 instruction has undefined behavior. This implies that jumps to labels
3034 defined in other functions have undefined behavior as well.</p>
3035
3036<h5>Implementation:</h5>
3037
3038<p>This is typically implemented with a jump through a register.</p>
3039
3040<h5>Example:</h5>
3041<pre>
Chris Lattnerd04cb6d2009-10-28 00:19:10 +0000[diff] [blame]3042 indirectbr i8* %Addr, [ label %bb1, label %bb2, label %bb3 ]
Chris Lattner3ed871f2009-10-27 19:13:16 +0000[diff] [blame]3043</pre>
3044
3045</div>
3046
3047
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3048<!-- _______________________________________________________________________ -->
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3049<div class="doc_subsubsection">
3050 <a name="i_invoke">'<tt>invoke</tt>' Instruction</a>
3051</div>
3052
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3053<div class="doc_text">
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3054
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3055<h5>Syntax:</h5>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3056<pre>
Devang Patel02256232008-10-07 17:48:33 +0000[diff] [blame]3057 &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]3058 to label &lt;normal label&gt; unwind label &lt;exception label&gt;
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3059</pre>
3060
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]3061<h5>Overview:</h5>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3062<p>The '<tt>invoke</tt>' instruction causes control to transfer to a specified
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3063 function, with the possibility of control flow transfer to either the
3064 '<tt>normal</tt>' label or the '<tt>exception</tt>' label. If the callee
3065 function returns with the "<tt><a href="#i_ret">ret</a></tt>" instruction,
3066 control flow will return to the "normal" label. If the callee (or any
3067 indirect callees) returns with the "<a href="#i_unwind"><tt>unwind</tt></a>"
3068 instruction, control is interrupted and continued at the dynamically nearest
3069 "exception" label.</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3070
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3071<h5>Arguments:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3072<p>This instruction requires several arguments:</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3073
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3074<ol>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3075 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
3076 convention</a> the call should use. If none is specified, the call
3077 defaults to using C calling conventions.</li>
Devang Patel7e9b05e2008-10-06 18:50:38 +0000[diff] [blame]3078
3079 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3080 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
3081 '<tt>inreg</tt>' attributes are valid here.</li>
Devang Patel7e9b05e2008-10-06 18:50:38 +0000[diff] [blame]3082
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3083 <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]3084 function value being invoked. In most cases, this is a direct function
3085 invocation, but indirect <tt>invoke</tt>s are just as possible, branching
3086 off an arbitrary pointer to function value.</li>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3087
3088 <li>'<tt>function ptr val</tt>': An LLVM value containing a pointer to a
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3089 function to be invoked. </li>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3090
3091 <li>'<tt>function args</tt>': argument list whose types match the function
Chris Lattner47f2a832010-03-02 06:36:51 +0000[diff] [blame]3092 signature argument types and parameter attributes. All arguments must be
3093 of <a href="#t_firstclass">first class</a> type. If the function
3094 signature indicates the function accepts a variable number of arguments,
3095 the extra arguments can be specified.</li>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3096
3097 <li>'<tt>normal label</tt>': the label reached when the called function
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3098 executes a '<tt><a href="#i_ret">ret</a></tt>' instruction. </li>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3099
3100 <li>'<tt>exception label</tt>': the label reached when a callee returns with
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3101 the <a href="#i_unwind"><tt>unwind</tt></a> instruction. </li>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3102
Devang Patel02256232008-10-07 17:48:33 +0000[diff] [blame]3103 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3104 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
3105 '<tt>readnone</tt>' attributes are valid here.</li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3106</ol>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3107
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3108<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3109<p>This instruction is designed to operate as a standard
3110 '<tt><a href="#i_call">call</a></tt>' instruction in most regards. The
3111 primary difference is that it establishes an association with a label, which
3112 is used by the runtime library to unwind the stack.</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3113
3114<p>This instruction is used in languages with destructors to ensure that proper
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3115 cleanup is performed in the case of either a <tt>longjmp</tt> or a thrown
3116 exception. Additionally, this is important for implementation of
3117 '<tt>catch</tt>' clauses in high-level languages that support them.</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3118
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3119<p>For the purposes of the SSA form, the definition of the value returned by the
3120 '<tt>invoke</tt>' instruction is deemed to occur on the edge from the current
3121 block to the "normal" label. If the callee unwinds then no return value is
3122 available.</p>
Dan Gohman9069d892009-05-22 21:47:08 +0000[diff] [blame]3123
Chris Lattner97257f82010-01-15 18:08:37 +0000[diff] [blame]3124<p>Note that the code generator does not yet completely support unwind, and
3125that the invoke/unwind semantics are likely to change in future versions.</p>
3126
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3127<h5>Example:</h5>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3128<pre>
Nick Lewycky084ab472008-03-16 07:18:12 +0000[diff] [blame]3129 %retval = invoke i32 @Test(i32 15) to label %Continue
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]3130 unwind label %TestCleanup <i>; {i32}:retval set</i>
Nick Lewycky084ab472008-03-16 07:18:12 +0000[diff] [blame]3131 %retval = invoke <a href="#callingconv">coldcc</a> i32 %Testfnptr(i32 15) to label %Continue
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]3132 unwind label %TestCleanup <i>; {i32}:retval set</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3133</pre>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3134
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3135</div>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3136
Chris Lattner5ed60612003-09-03 00:41:47 +0000[diff] [blame]3137<!-- _______________________________________________________________________ -->
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3138
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3139<div class="doc_subsubsection"> <a name="i_unwind">'<tt>unwind</tt>'
3140Instruction</a> </div>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3141
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3142<div class="doc_text">
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3143
Chris Lattner5ed60612003-09-03 00:41:47 +0000[diff] [blame]3144<h5>Syntax:</h5>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3145<pre>
3146 unwind
3147</pre>
3148
Chris Lattner5ed60612003-09-03 00:41:47 +0000[diff] [blame]3149<h5>Overview:</h5>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3150<p>The '<tt>unwind</tt>' instruction unwinds the stack, continuing control flow
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3151 at the first callee in the dynamic call stack which used
3152 an <a href="#i_invoke"><tt>invoke</tt></a> instruction to perform the call.
3153 This is primarily used to implement exception handling.</p>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3154
Chris Lattner5ed60612003-09-03 00:41:47 +0000[diff] [blame]3155<h5>Semantics:</h5>
Chris Lattnerfe8519c2008-04-19 21:01:16 +0000[diff] [blame]3156<p>The '<tt>unwind</tt>' instruction causes execution of the current function to
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3157 immediately halt. The dynamic call stack is then searched for the
3158 first <a href="#i_invoke"><tt>invoke</tt></a> instruction on the call stack.
3159 Once found, execution continues at the "exceptional" destination block
3160 specified by the <tt>invoke</tt> instruction. If there is no <tt>invoke</tt>
3161 instruction in the dynamic call chain, undefined behavior results.</p>
3162
Chris Lattner97257f82010-01-15 18:08:37 +0000[diff] [blame]3163<p>Note that the code generator does not yet completely support unwind, and
3164that the invoke/unwind semantics are likely to change in future versions.</p>
3165
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3166</div>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3167
3168<!-- _______________________________________________________________________ -->
3169
3170<div class="doc_subsubsection"> <a name="i_unreachable">'<tt>unreachable</tt>'
3171Instruction</a> </div>
3172
3173<div class="doc_text">
3174
3175<h5>Syntax:</h5>
3176<pre>
3177 unreachable
3178</pre>
3179
3180<h5>Overview:</h5>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3181<p>The '<tt>unreachable</tt>' instruction has no defined semantics. This
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3182 instruction is used to inform the optimizer that a particular portion of the
3183 code is not reachable. This can be used to indicate that the code after a
3184 no-return function cannot be reached, and other facts.</p>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3185
3186<h5>Semantics:</h5>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3187<p>The '<tt>unreachable</tt>' instruction has no defined semantics.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3188
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3189</div>
3190
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3191<!-- ======================================================================= -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3192<div class="doc_subsection"> <a name="binaryops">Binary Operations</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3193
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3194<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3195
3196<p>Binary operators are used to do most of the computation in a program. They
3197 require two operands of the same type, execute an operation on them, and
3198 produce a single value. The operands might represent multiple data, as is
3199 the case with the <a href="#t_vector">vector</a> data type. The result value
3200 has the same type as its operands.</p>
3201
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3202<p>There are several different binary operators:</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3203
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3204</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3205
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3206<!-- _______________________________________________________________________ -->
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3207<div class="doc_subsubsection">
3208 <a name="i_add">'<tt>add</tt>' Instruction</a>
3209</div>
3210
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3211<div class="doc_text">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3212
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3213<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3214<pre>
Dan Gohmanb07de442009-07-20 22:41:19 +0000[diff] [blame]3215 &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]3216 &lt;result&gt; = add nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3217 &lt;result&gt; = add nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3218 &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]3219</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3220
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3221<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3222<p>The '<tt>add</tt>' instruction returns the sum of its two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3223
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3224<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3225<p>The two arguments to the '<tt>add</tt>' instruction must
3226 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3227 integer values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3228
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3229<h5>Semantics:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3230<p>The value produced is the integer sum of the two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3231
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3232<p>If the sum has unsigned overflow, the result returned is the mathematical
3233 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]3234
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3235<p>Because LLVM integers use a two's complement representation, this instruction
3236 is appropriate for both signed and unsigned integers.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3237
Dan Gohman902dfff2009-07-22 22:44:56 +0000[diff] [blame]3238<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3239 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3240 <tt>nsw</tt> keywords are present, the result value of the <tt>add</tt>
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]3241 is a <a href="#trapvalues">trap value</a> if unsigned and/or signed overflow,
3242 respectively, occurs.</p>
Dan Gohmanb07de442009-07-20 22:41:19 +0000[diff] [blame]3243
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3244<h5>Example:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3245<pre>
3246 &lt;result&gt; = add i32 4, %var <i>; yields {i32}:result = 4 + %var</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3247</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3248
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3249</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3250
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3251<!-- _______________________________________________________________________ -->
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3252<div class="doc_subsubsection">
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3253 <a name="i_fadd">'<tt>fadd</tt>' Instruction</a>
3254</div>
3255
3256<div class="doc_text">
3257
3258<h5>Syntax:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3259<pre>
3260 &lt;result&gt; = fadd &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3261</pre>
3262
3263<h5>Overview:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3264<p>The '<tt>fadd</tt>' instruction returns the sum of its two operands.</p>
3265
3266<h5>Arguments:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3267<p>The two arguments to the '<tt>fadd</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3268 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3269 floating point values. Both arguments must have identical types.</p>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3270
3271<h5>Semantics:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3272<p>The value produced is the floating point sum of the two operands.</p>
3273
3274<h5>Example:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3275<pre>
3276 &lt;result&gt; = fadd float 4.0, %var <i>; yields {float}:result = 4.0 + %var</i>
3277</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3278
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3279</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3280
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3281<!-- _______________________________________________________________________ -->
3282<div class="doc_subsubsection">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3283 <a name="i_sub">'<tt>sub</tt>' Instruction</a>
3284</div>
3285
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3286<div class="doc_text">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3287
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3288<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3289<pre>
Dan Gohman902dfff2009-07-22 22:44:56 +0000[diff] [blame]3290 &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]3291 &lt;result&gt; = sub nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3292 &lt;result&gt; = sub nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3293 &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]3294</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3295
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3296<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3297<p>The '<tt>sub</tt>' instruction returns the difference of its two
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3298 operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3299
3300<p>Note that the '<tt>sub</tt>' instruction is used to represent the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3301 '<tt>neg</tt>' instruction present in most other intermediate
3302 representations.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3303
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3304<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3305<p>The two arguments to the '<tt>sub</tt>' instruction must
3306 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3307 integer values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3308
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3309<h5>Semantics:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3310<p>The value produced is the integer difference of the two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3311
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3312<p>If the difference has unsigned overflow, the result returned is the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3313 mathematical result modulo 2<sup>n</sup>, where n is the bit width of the
3314 result.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3315
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3316<p>Because LLVM integers use a two's complement representation, this instruction
3317 is appropriate for both signed and unsigned integers.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3318
Dan Gohman902dfff2009-07-22 22:44:56 +0000[diff] [blame]3319<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3320 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3321 <tt>nsw</tt> keywords are present, the result value of the <tt>sub</tt>
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]3322 is a <a href="#trapvalues">trap value</a> if unsigned and/or signed overflow,
3323 respectively, occurs.</p>
Dan Gohmanb07de442009-07-20 22:41:19 +0000[diff] [blame]3324
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3325<h5>Example:</h5>
Bill Wendling2d8b9a82007-05-29 09:42:13 +0000[diff] [blame]3326<pre>
3327 &lt;result&gt; = sub i32 4, %var <i>; yields {i32}:result = 4 - %var</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3328 &lt;result&gt; = sub i32 0, %val <i>; yields {i32}:result = -%var</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3329</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3330
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3331</div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3332
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3333<!-- _______________________________________________________________________ -->
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3334<div class="doc_subsubsection">
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3335 <a name="i_fsub">'<tt>fsub</tt>' Instruction</a>
3336</div>
3337
3338<div class="doc_text">
3339
3340<h5>Syntax:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3341<pre>
3342 &lt;result&gt; = fsub &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3343</pre>
3344
3345<h5>Overview:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3346<p>The '<tt>fsub</tt>' instruction returns the difference of its two
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3347 operands.</p>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3348
3349<p>Note that the '<tt>fsub</tt>' instruction is used to represent the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3350 '<tt>fneg</tt>' instruction present in most other intermediate
3351 representations.</p>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3352
3353<h5>Arguments:</h5>
Bill Wendling972b7202009-07-20 02:32:41 +0000[diff] [blame]3354<p>The two arguments to the '<tt>fsub</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3355 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3356 floating point values. Both arguments must have identical types.</p>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3357
3358<h5>Semantics:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3359<p>The value produced is the floating point difference of the two operands.</p>
3360
3361<h5>Example:</h5>
3362<pre>
3363 &lt;result&gt; = fsub float 4.0, %var <i>; yields {float}:result = 4.0 - %var</i>
3364 &lt;result&gt; = fsub float -0.0, %val <i>; yields {float}:result = -%var</i>
3365</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3366
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3367</div>
3368
3369<!-- _______________________________________________________________________ -->
3370<div class="doc_subsubsection">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3371 <a name="i_mul">'<tt>mul</tt>' Instruction</a>
3372</div>
3373
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3374<div class="doc_text">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3375
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3376<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3377<pre>
Dan Gohman902dfff2009-07-22 22:44:56 +0000[diff] [blame]3378 &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]3379 &lt;result&gt; = mul nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3380 &lt;result&gt; = mul nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3381 &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]3382</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3383
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3384<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3385<p>The '<tt>mul</tt>' instruction returns the product of its two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3386
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3387<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3388<p>The two arguments to the '<tt>mul</tt>' instruction must
3389 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3390 integer values. Both arguments must have identical types.</p>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3391
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3392<h5>Semantics:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3393<p>The value produced is the integer product of the two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3394
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3395<p>If the result of the multiplication has unsigned overflow, the result
3396 returned is the mathematical result modulo 2<sup>n</sup>, where n is the bit
3397 width of the result.</p>
3398
3399<p>Because LLVM integers use a two's complement representation, and the result
3400 is the same width as the operands, this instruction returns the correct
3401 result for both signed and unsigned integers. If a full product
3402 (e.g. <tt>i32</tt>x<tt>i32</tt>-><tt>i64</tt>) is needed, the operands should
3403 be sign-extended or zero-extended as appropriate to the width of the full
3404 product.</p>
3405
Dan Gohman902dfff2009-07-22 22:44:56 +0000[diff] [blame]3406<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3407 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3408 <tt>nsw</tt> keywords are present, the result value of the <tt>mul</tt>
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]3409 is a <a href="#trapvalues">trap value</a> if unsigned and/or signed overflow,
3410 respectively, occurs.</p>
Dan Gohmanb07de442009-07-20 22:41:19 +0000[diff] [blame]3411
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3412<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3413<pre>
3414 &lt;result&gt; = mul i32 4, %var <i>; yields {i32}:result = 4 * %var</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3415</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3416
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3417</div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3418
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3419<!-- _______________________________________________________________________ -->
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3420<div class="doc_subsubsection">
3421 <a name="i_fmul">'<tt>fmul</tt>' Instruction</a>
3422</div>
3423
3424<div class="doc_text">
3425
3426<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3427<pre>
3428 &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]3429</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3430
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3431<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3432<p>The '<tt>fmul</tt>' instruction returns the product of its two operands.</p>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3433
3434<h5>Arguments:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3435<p>The two arguments to the '<tt>fmul</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3436 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3437 floating point values. Both arguments must have identical types.</p>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3438
3439<h5>Semantics:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3440<p>The value produced is the floating point product of the two operands.</p>
3441
3442<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3443<pre>
3444 &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]3445</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3446
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3447</div>
3448
3449<!-- _______________________________________________________________________ -->
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3450<div class="doc_subsubsection"> <a name="i_udiv">'<tt>udiv</tt>' Instruction
3451</a></div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3452
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3453<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3454
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3455<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3456<pre>
3457 &lt;result&gt; = udiv &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3458</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3459
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3460<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3461<p>The '<tt>udiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3462
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3463<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3464<p>The two arguments to the '<tt>udiv</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3465 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3466 values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3467
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3468<h5>Semantics:</h5>
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3469<p>The value produced is the unsigned integer quotient of the two operands.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3470
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3471<p>Note that unsigned integer division and signed integer division are distinct
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3472 operations; for signed integer division, use '<tt>sdiv</tt>'.</p>
3473
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3474<p>Division by zero leads to undefined behavior.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]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
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3616 has the same sign as the dividend, <tt>op1</tt>), not the <i>modulo</i>
3617 operator (where the result has the same sign as the divisor, <tt>op2</tt>) of
3618 a value. For more information about the difference,
3619 see <a href="http://mathforum.org/dr.math/problems/anne.4.28.99.html">The
3620 Math Forum</a>. For a table of how this is implemented in various languages,
3621 please see <a href="http://en.wikipedia.org/wiki/Modulo_operation">
3622 Wikipedia: modulo operation</a>.</p>
3623
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3624<p>Note that signed integer remainder and unsigned integer remainder are
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3625 distinct operations; for unsigned integer remainder, use '<tt>urem</tt>'.</p>
3626
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3627<p>Taking the remainder of a division by zero leads to undefined behavior.
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3628 Overflow also leads to undefined behavior; this is a rare case, but can
3629 occur, for example, by taking the remainder of a 32-bit division of
3630 -2147483648 by -1. (The remainder doesn't actually overflow, but this rule
3631 lets srem be implemented using instructions that return both the result of
3632 the division and the remainder.)</p>
3633
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3634<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3635<pre>
3636 &lt;result&gt; = srem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3637</pre>
3638
3639</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3640
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3641<!-- _______________________________________________________________________ -->
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3642<div class="doc_subsubsection">
3643 <a name="i_frem">'<tt>frem</tt>' Instruction</a> </div>
3644
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3645<div class="doc_text">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3646
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3647<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3648<pre>
3649 &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]3650</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3651
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3652<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3653<p>The '<tt>frem</tt>' instruction returns the remainder from the division of
3654 its two operands.</p>
3655
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3656<h5>Arguments:</h5>
3657<p>The two arguments to the '<tt>frem</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3658 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3659 floating point values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3660
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3661<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3662<p>This instruction returns the <i>remainder</i> of a division. The remainder
3663 has the same sign as the dividend.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3664
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3665<h5>Example:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3666<pre>
3667 &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]3668</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3669
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3670</div>
Robert Bocchino820bc75b2006-02-17 21:18:08 +0000[diff] [blame]3671
Reid Spencer2ab01932007-02-02 13:57:07 +0000[diff] [blame]3672<!-- ======================================================================= -->
3673<div class="doc_subsection"> <a name="bitwiseops">Bitwise Binary
3674Operations</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3675
Reid Spencer2ab01932007-02-02 13:57:07 +0000[diff] [blame]3676<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3677
3678<p>Bitwise binary operators are used to do various forms of bit-twiddling in a
3679 program. They are generally very efficient instructions and can commonly be
3680 strength reduced from other instructions. They require two operands of the
3681 same type, execute an operation on them, and produce a single value. The
3682 resulting value is the same type as its operands.</p>
3683
Reid Spencer2ab01932007-02-02 13:57:07 +0000[diff] [blame]3684</div>
3685
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3686<!-- _______________________________________________________________________ -->
3687<div class="doc_subsubsection"> <a name="i_shl">'<tt>shl</tt>'
3688Instruction</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3689
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3690<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3691
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3692<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3693<pre>
3694 &lt;result&gt; = shl &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3695</pre>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]3696
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3697<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3698<p>The '<tt>shl</tt>' instruction returns the first operand shifted to the left
3699 a specified number of bits.</p>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]3700
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3701<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3702<p>Both arguments to the '<tt>shl</tt>' instruction must be the
3703 same <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3704 integer type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3705
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3706<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3707<p>The value produced is <tt>op1</tt> * 2<sup><tt>op2</tt></sup> mod
3708 2<sup>n</sup>, where <tt>n</tt> is the width of the result. If <tt>op2</tt>
3709 is (statically or dynamically) negative or equal to or larger than the number
3710 of bits in <tt>op1</tt>, the result is undefined. If the arguments are
3711 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
3712 shift amount in <tt>op2</tt>.</p>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]3713
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3714<h5>Example:</h5>
3715<pre>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3716 &lt;result&gt; = shl i32 4, %var <i>; yields {i32}: 4 &lt;&lt; %var</i>
3717 &lt;result&gt; = shl i32 4, 2 <i>; yields {i32}: 16</i>
3718 &lt;result&gt; = shl i32 1, 10 <i>; yields {i32}: 1024</i>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]3719 &lt;result&gt; = shl i32 1, 32 <i>; undefined</i>
Mon P Wang4dd832d2008-12-09 05:46:39 +0000[diff] [blame]3720 &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]3721</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3722
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3723</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3724
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3725<!-- _______________________________________________________________________ -->
3726<div class="doc_subsubsection"> <a name="i_lshr">'<tt>lshr</tt>'
3727Instruction</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3728
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3729<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3730
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3731<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3732<pre>
3733 &lt;result&gt; = lshr &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3734</pre>
3735
3736<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3737<p>The '<tt>lshr</tt>' instruction (logical shift right) returns the first
3738 operand shifted to the right a specified number of bits with zero fill.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3739
3740<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3741<p>Both arguments to the '<tt>lshr</tt>' instruction must be the same
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3742 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3743 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3744
3745<h5>Semantics:</h5>
3746<p>This instruction always performs a logical shift right operation. The most
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3747 significant bits of the result will be filled with zero bits after the shift.
3748 If <tt>op2</tt> is (statically or dynamically) equal to or larger than the
3749 number of bits in <tt>op1</tt>, the result is undefined. If the arguments are
3750 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
3751 shift amount in <tt>op2</tt>.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3752
3753<h5>Example:</h5>
3754<pre>
3755 &lt;result&gt; = lshr i32 4, 1 <i>; yields {i32}:result = 2</i>
3756 &lt;result&gt; = lshr i32 4, 2 <i>; yields {i32}:result = 1</i>
3757 &lt;result&gt; = lshr i8 4, 3 <i>; yields {i8}:result = 0</i>
3758 &lt;result&gt; = lshr i8 -2, 1 <i>; yields {i8}:result = 0x7FFFFFFF </i>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]3759 &lt;result&gt; = lshr i32 1, 32 <i>; undefined</i>
Mon P Wang4dd832d2008-12-09 05:46:39 +0000[diff] [blame]3760 &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]3761</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3762
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3763</div>
3764
Reid Spencer2ab01932007-02-02 13:57:07 +0000[diff] [blame]3765<!-- _______________________________________________________________________ -->
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3766<div class="doc_subsubsection"> <a name="i_ashr">'<tt>ashr</tt>'
3767Instruction</a> </div>
3768<div class="doc_text">
3769
3770<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3771<pre>
3772 &lt;result&gt; = ashr &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3773</pre>
3774
3775<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3776<p>The '<tt>ashr</tt>' instruction (arithmetic shift right) returns the first
3777 operand shifted to the right a specified number of bits with sign
3778 extension.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3779
3780<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3781<p>Both arguments to the '<tt>ashr</tt>' instruction must be the same
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3782 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3783 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3784
3785<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3786<p>This instruction always performs an arithmetic shift right operation, The
3787 most significant bits of the result will be filled with the sign bit
3788 of <tt>op1</tt>. If <tt>op2</tt> is (statically or dynamically) equal to or
3789 larger than the number of bits in <tt>op1</tt>, the result is undefined. If
3790 the arguments are vectors, each vector element of <tt>op1</tt> is shifted by
3791 the corresponding shift amount in <tt>op2</tt>.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3792
3793<h5>Example:</h5>
3794<pre>
3795 &lt;result&gt; = ashr i32 4, 1 <i>; yields {i32}:result = 2</i>
3796 &lt;result&gt; = ashr i32 4, 2 <i>; yields {i32}:result = 1</i>
3797 &lt;result&gt; = ashr i8 4, 3 <i>; yields {i8}:result = 0</i>
3798 &lt;result&gt; = ashr i8 -2, 1 <i>; yields {i8}:result = -1</i>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]3799 &lt;result&gt; = ashr i32 1, 32 <i>; undefined</i>
Mon P Wang4dd832d2008-12-09 05:46:39 +0000[diff] [blame]3800 &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]3801</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3802
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3803</div>
3804
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3805<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3806<div class="doc_subsubsection"> <a name="i_and">'<tt>and</tt>'
3807Instruction</a> </div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3808
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3809<div class="doc_text">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3810
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3811<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3812<pre>
Gabor Greif0f75ad02008-08-07 21:46:00 +0000[diff] [blame]3813 &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]3814</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3815
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3816<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3817<p>The '<tt>and</tt>' instruction returns the bitwise logical and of its two
3818 operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3819
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3820<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3821<p>The two arguments to the '<tt>and</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3822 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3823 values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3824
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3825<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3826<p>The truth table used for the '<tt>and</tt>' instruction is:</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3827
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3828<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3829 <tbody>
3830 <tr>
3831 <td>In0</td>
3832 <td>In1</td>
3833 <td>Out</td>
3834 </tr>
3835 <tr>
3836 <td>0</td>
3837 <td>0</td>
3838 <td>0</td>
3839 </tr>
3840 <tr>
3841 <td>0</td>
3842 <td>1</td>
3843 <td>0</td>
3844 </tr>
3845 <tr>
3846 <td>1</td>
3847 <td>0</td>
3848 <td>0</td>
3849 </tr>
3850 <tr>
3851 <td>1</td>
3852 <td>1</td>
3853 <td>1</td>
3854 </tr>
3855 </tbody>
3856</table>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3857
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3858<h5>Example:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3859<pre>
3860 &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]3861 &lt;result&gt; = and i32 15, 40 <i>; yields {i32}:result = 8</i>
3862 &lt;result&gt; = and i32 4, 8 <i>; yields {i32}:result = 0</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3863</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3864</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3865<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3866<div class="doc_subsubsection"> <a name="i_or">'<tt>or</tt>' Instruction</a> </div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3867
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3868<div class="doc_text">
3869
3870<h5>Syntax:</h5>
3871<pre>
3872 &lt;result&gt; = or &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3873</pre>
3874
3875<h5>Overview:</h5>
3876<p>The '<tt>or</tt>' instruction returns the bitwise logical inclusive or of its
3877 two operands.</p>
3878
3879<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3880<p>The two arguments to the '<tt>or</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3881 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3882 values. Both arguments must have identical types.</p>
3883
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3884<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3885<p>The truth table used for the '<tt>or</tt>' instruction is:</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3886
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3887<table border="1" cellspacing="0" cellpadding="4">
3888 <tbody>
3889 <tr>
3890 <td>In0</td>
3891 <td>In1</td>
3892 <td>Out</td>
3893 </tr>
3894 <tr>
3895 <td>0</td>
3896 <td>0</td>
3897 <td>0</td>
3898 </tr>
3899 <tr>
3900 <td>0</td>
3901 <td>1</td>
3902 <td>1</td>
3903 </tr>
3904 <tr>
3905 <td>1</td>
3906 <td>0</td>
3907 <td>1</td>
3908 </tr>
3909 <tr>
3910 <td>1</td>
3911 <td>1</td>
3912 <td>1</td>
3913 </tr>
3914 </tbody>
3915</table>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3916
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3917<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3918<pre>
3919 &lt;result&gt; = or i32 4, %var <i>; yields {i32}:result = 4 | %var</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3920 &lt;result&gt; = or i32 15, 40 <i>; yields {i32}:result = 47</i>
3921 &lt;result&gt; = or i32 4, 8 <i>; yields {i32}:result = 12</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3922</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3923
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3924</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3925
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3926<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3927<div class="doc_subsubsection"> <a name="i_xor">'<tt>xor</tt>'
3928Instruction</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3929
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3930<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3931
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3932<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3933<pre>
3934 &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]3935</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3936
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3937<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3938<p>The '<tt>xor</tt>' instruction returns the bitwise logical exclusive or of
3939 its two operands. The <tt>xor</tt> is used to implement the "one's
3940 complement" operation, which is the "~" operator in C.</p>
3941
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3942<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3943<p>The two arguments to the '<tt>xor</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3944 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3945 values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3946
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3947<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3948<p>The truth table used for the '<tt>xor</tt>' instruction is:</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3949
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3950<table border="1" cellspacing="0" cellpadding="4">
3951 <tbody>
3952 <tr>
3953 <td>In0</td>
3954 <td>In1</td>
3955 <td>Out</td>
3956 </tr>
3957 <tr>
3958 <td>0</td>
3959 <td>0</td>
3960 <td>0</td>
3961 </tr>
3962 <tr>
3963 <td>0</td>
3964 <td>1</td>
3965 <td>1</td>
3966 </tr>
3967 <tr>
3968 <td>1</td>
3969 <td>0</td>
3970 <td>1</td>
3971 </tr>
3972 <tr>
3973 <td>1</td>
3974 <td>1</td>
3975 <td>0</td>
3976 </tr>
3977 </tbody>
3978</table>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3979
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3980<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3981<pre>
3982 &lt;result&gt; = xor i32 4, %var <i>; yields {i32}:result = 4 ^ %var</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3983 &lt;result&gt; = xor i32 15, 40 <i>; yields {i32}:result = 39</i>
3984 &lt;result&gt; = xor i32 4, 8 <i>; yields {i32}:result = 12</i>
3985 &lt;result&gt; = xor i32 %V, -1 <i>; yields {i32}:result = ~%V</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3986</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3987
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3988</div>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3989
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3990<!-- ======================================================================= -->
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3991<div class="doc_subsection">
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]3992 <a name="vectorops">Vector Operations</a>
3993</div>
3994
3995<div class="doc_text">
3996
3997<p>LLVM supports several instructions to represent vector operations in a
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3998 target-independent manner. These instructions cover the element-access and
3999 vector-specific operations needed to process vectors effectively. While LLVM
4000 does directly support these vector operations, many sophisticated algorithms
4001 will want to use target-specific intrinsics to take full advantage of a
4002 specific target.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4003
4004</div>
4005
4006<!-- _______________________________________________________________________ -->
4007<div class="doc_subsubsection">
4008 <a name="i_extractelement">'<tt>extractelement</tt>' Instruction</a>
4009</div>
4010
4011<div class="doc_text">
4012
4013<h5>Syntax:</h5>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4014<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4015 &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]4016</pre>
4017
4018<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4019<p>The '<tt>extractelement</tt>' instruction extracts a single scalar element
4020 from a vector at a specified index.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4021
4022
4023<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4024<p>The first operand of an '<tt>extractelement</tt>' instruction is a value
4025 of <a href="#t_vector">vector</a> type. The second operand is an index
4026 indicating the position from which to extract the element. The index may be
4027 a variable.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4028
4029<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4030<p>The result is a scalar of the same type as the element type of
4031 <tt>val</tt>. Its value is the value at position <tt>idx</tt> of
4032 <tt>val</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
4033 results are undefined.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4034
4035<h5>Example:</h5>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4036<pre>
Gabor Greif03ab4dc2009-10-28 13:14:50 +0000[diff] [blame]4037 &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]4038</pre>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4039
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4040</div>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4041
4042<!-- _______________________________________________________________________ -->
4043<div class="doc_subsubsection">
4044 <a name="i_insertelement">'<tt>insertelement</tt>' Instruction</a>
4045</div>
4046
4047<div class="doc_text">
4048
4049<h5>Syntax:</h5>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4050<pre>
Dan Gohman43ba0672008-05-12 23:38:42 +0000[diff] [blame]4051 &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]4052</pre>
4053
4054<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4055<p>The '<tt>insertelement</tt>' instruction inserts a scalar element into a
4056 vector at a specified index.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4057
4058<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4059<p>The first operand of an '<tt>insertelement</tt>' instruction is a value
4060 of <a href="#t_vector">vector</a> type. The second operand is a scalar value
4061 whose type must equal the element type of the first operand. The third
4062 operand is an index indicating the position at which to insert the value.
4063 The index may be a variable.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4064
4065<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4066<p>The result is a vector of the same type as <tt>val</tt>. Its element values
4067 are those of <tt>val</tt> except at position <tt>idx</tt>, where it gets the
4068 value <tt>elt</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
4069 results are undefined.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4070
4071<h5>Example:</h5>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4072<pre>
Gabor Greif03ab4dc2009-10-28 13:14:50 +0000[diff] [blame]4073 &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]4074</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4075
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4076</div>
4077
4078<!-- _______________________________________________________________________ -->
4079<div class="doc_subsubsection">
4080 <a name="i_shufflevector">'<tt>shufflevector</tt>' Instruction</a>
4081</div>
4082
4083<div class="doc_text">
4084
4085<h5>Syntax:</h5>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4086<pre>
Mon P Wang25f01062008-11-10 04:46:22 +0000[diff] [blame]4087 &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]4088</pre>
4089
4090<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4091<p>The '<tt>shufflevector</tt>' instruction constructs a permutation of elements
4092 from two input vectors, returning a vector with the same element type as the
4093 input and length that is the same as the shuffle mask.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4094
4095<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4096<p>The first two operands of a '<tt>shufflevector</tt>' instruction are vectors
4097 with types that match each other. The third argument is a shuffle mask whose
4098 element type is always 'i32'. The result of the instruction is a vector
4099 whose length is the same as the shuffle mask and whose element type is the
4100 same as the element type of the first two operands.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4101
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4102<p>The shuffle mask operand is required to be a constant vector with either
4103 constant integer or undef values.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4104
4105<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4106<p>The elements of the two input vectors are numbered from left to right across
4107 both of the vectors. The shuffle mask operand specifies, for each element of
4108 the result vector, which element of the two input vectors the result element
4109 gets. The element selector may be undef (meaning "don't care") and the
4110 second operand may be undef if performing a shuffle from only one vector.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4111
4112<h5>Example:</h5>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4113<pre>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4114 &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]4115 &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]4116 &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]4117 &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]4118 &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]4119 &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]4120 &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]4121 &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]4122</pre>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4123
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4124</div>
Tanya Lattnerb138bbe2006-04-14 19:24:33 +0000[diff] [blame]4125
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4126<!-- ======================================================================= -->
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4127<div class="doc_subsection">
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4128 <a name="aggregateops">Aggregate Operations</a>
4129</div>
4130
4131<div class="doc_text">
4132
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]4133<p>LLVM supports several instructions for working with
4134 <a href="#t_aggregate">aggregate</a> values.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4135
4136</div>
4137
4138<!-- _______________________________________________________________________ -->
4139<div class="doc_subsubsection">
4140 <a name="i_extractvalue">'<tt>extractvalue</tt>' Instruction</a>
4141</div>
4142
4143<div class="doc_text">
4144
4145<h5>Syntax:</h5>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4146<pre>
4147 &lt;result&gt; = extractvalue &lt;aggregate type&gt; &lt;val&gt;, &lt;idx&gt;{, &lt;idx&gt;}*
4148</pre>
4149
4150<h5>Overview:</h5>
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]4151<p>The '<tt>extractvalue</tt>' instruction extracts the value of a member field
4152 from an <a href="#t_aggregate">aggregate</a> value.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4153
4154<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4155<p>The first operand of an '<tt>extractvalue</tt>' instruction is a value
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]4156 of <a href="#t_struct">struct</a>, <a href="#t_union">union</a> or
4157 <a href="#t_array">array</a> type. The operands are constant indices to
4158 specify which value to extract in a similar manner as indices in a
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4159 '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4160
4161<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4162<p>The result is the value at the position in the aggregate specified by the
4163 index operands.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4164
4165<h5>Example:</h5>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4166<pre>
Gabor Greif03ab4dc2009-10-28 13:14:50 +0000[diff] [blame]4167 &lt;result&gt; = extractvalue {i32, float} %agg, 0 <i>; yields i32</i>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4168</pre>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4169
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4170</div>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4171
4172<!-- _______________________________________________________________________ -->
4173<div class="doc_subsubsection">
4174 <a name="i_insertvalue">'<tt>insertvalue</tt>' Instruction</a>
4175</div>
4176
4177<div class="doc_text">
4178
4179<h5>Syntax:</h5>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4180<pre>
Jeffrey Yasskinf991bbb2010-01-11 19:19:26 +0000[diff] [blame]4181 &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]4182</pre>
4183
4184<h5>Overview:</h5>
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]4185<p>The '<tt>insertvalue</tt>' instruction inserts a value into a member field
4186 in an <a href="#t_aggregate">aggregate</a> value.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4187
4188<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4189<p>The first operand of an '<tt>insertvalue</tt>' instruction is a value
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]4190 of <a href="#t_struct">struct</a>, <a href="#t_union">union</a> or
4191 <a href="#t_array">array</a> type. The second operand is a first-class
4192 value to insert. The following operands are constant indices indicating
4193 the position at which to insert the value in a similar manner as indices in a
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4194 '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction. The
4195 value to insert must have the same type as the value identified by the
4196 indices.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4197
4198<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4199<p>The result is an aggregate of the same type as <tt>val</tt>. Its value is
4200 that of <tt>val</tt> except that the value at the position specified by the
4201 indices is that of <tt>elt</tt>.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4202
4203<h5>Example:</h5>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4204<pre>
Jeffrey Yasskinf991bbb2010-01-11 19:19:26 +0000[diff] [blame]4205 %agg1 = insertvalue {i32, float} undef, i32 1, 0 <i>; yields {i32 1, float undef}</i>
4206 %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]4207</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4208
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4209</div>
4210
4211
4212<!-- ======================================================================= -->
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4213<div class="doc_subsection">
Chris Lattner6ab66722006-08-15 00:45:58 +0000[diff] [blame]4214 <a name="memoryops">Memory Access and Addressing Operations</a>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4215</div>
4216
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4217<div class="doc_text">
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4218
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4219<p>A key design point of an SSA-based representation is how it represents
4220 memory. In LLVM, no memory locations are in SSA form, which makes things
Victor Hernandeza70c6df2009-10-26 23:44:29 +0000[diff] [blame]4221 very simple. This section describes how to read, write, and allocate
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4222 memory in LLVM.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4223
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4224</div>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4225
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4226<!-- _______________________________________________________________________ -->
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4227<div class="doc_subsubsection">
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4228 <a name="i_alloca">'<tt>alloca</tt>' Instruction</a>
4229</div>
4230
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4231<div class="doc_text">
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4232
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4233<h5>Syntax:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4234<pre>
Dan Gohman2140a742010-05-28 01:14:11 +0000[diff] [blame]4235 &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]4236</pre>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4237
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4238<h5>Overview:</h5>
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]4239<p>The '<tt>alloca</tt>' instruction allocates memory on the stack frame of the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4240 currently executing function, to be automatically released when this function
4241 returns to its caller. The object is always allocated in the generic address
4242 space (address space zero).</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4243
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4244<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4245<p>The '<tt>alloca</tt>' instruction
4246 allocates <tt>sizeof(&lt;type&gt;)*NumElements</tt> bytes of memory on the
4247 runtime stack, returning a pointer of the appropriate type to the program.
4248 If "NumElements" is specified, it is the number of elements allocated,
4249 otherwise "NumElements" is defaulted to be one. If a constant alignment is
4250 specified, the value result of the allocation is guaranteed to be aligned to
4251 at least that boundary. If not specified, or if zero, the target can choose
4252 to align the allocation on any convenient boundary compatible with the
4253 type.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4254
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4255<p>'<tt>type</tt>' may be any sized type.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4256
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4257<h5>Semantics:</h5>
Bill Wendling9ee6a312009-05-08 20:49:29 +0000[diff] [blame]4258<p>Memory is allocated; a pointer is returned. The operation is undefined if
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4259 there is insufficient stack space for the allocation. '<tt>alloca</tt>'d
4260 memory is automatically released when the function returns. The
4261 '<tt>alloca</tt>' instruction is commonly used to represent automatic
4262 variables that must have an address available. When the function returns
4263 (either with the <tt><a href="#i_ret">ret</a></tt>
4264 or <tt><a href="#i_unwind">unwind</a></tt> instructions), the memory is
4265 reclaimed. Allocating zero bytes is legal, but the result is undefined.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4266
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4267<h5>Example:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4268<pre>
Dan Gohman7a5acb52009-01-04 23:49:44 +0000[diff] [blame]4269 %ptr = alloca i32 <i>; yields {i32*}:ptr</i>
4270 %ptr = alloca i32, i32 4 <i>; yields {i32*}:ptr</i>
4271 %ptr = alloca i32, i32 4, align 1024 <i>; yields {i32*}:ptr</i>
4272 %ptr = alloca i32, align 1024 <i>; yields {i32*}:ptr</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4273</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4274
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4275</div>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4276
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4277<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]4278<div class="doc_subsubsection"> <a name="i_load">'<tt>load</tt>'
4279Instruction</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4280
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4281<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4282
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4283<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4284<pre>
Bill Wendlingbc4024f2010-02-25 21:23:24 +0000[diff] [blame]4285 &lt;result&gt; = load &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;][, !nontemporal !&lt;index&gt;]
4286 &lt;result&gt; = volatile load &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;][, !nontemporal !&lt;index&gt;]
4287 !&lt;index&gt; = !{ i32 1 }
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4288</pre>
4289
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4290<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4291<p>The '<tt>load</tt>' instruction is used to read from memory.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4292
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4293<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4294<p>The argument to the '<tt>load</tt>' instruction specifies the memory address
4295 from which to load. The pointer must point to
4296 a <a href="#t_firstclass">first class</a> type. If the <tt>load</tt> is
4297 marked as <tt>volatile</tt>, then the optimizer is not allowed to modify the
Jeffrey Yasskin5d284ae2010-04-26 21:21:24 +0000[diff] [blame]4298 number or order of execution of this <tt>load</tt> with other <a
4299 href="#volatile">volatile operations</a>.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4300
Bill Wendlingbc4024f2010-02-25 21:23:24 +0000[diff] [blame]4301<p>The optional constant <tt>align</tt> argument specifies the alignment of the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4302 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]4303 omitted <tt>align</tt> argument means that the operation has the preferential
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4304 alignment for the target. It is the responsibility of the code emitter to
4305 ensure that the alignment information is correct. Overestimating the
Bill Wendlingbc4024f2010-02-25 21:23:24 +0000[diff] [blame]4306 alignment results in undefined behavior. Underestimating the alignment may
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4307 produce less efficient code. An alignment of 1 is always safe.</p>
4308
Bill Wendlingbc4024f2010-02-25 21:23:24 +0000[diff] [blame]4309<p>The optional <tt>!nontemporal</tt> metadata must reference a single
4310 metatadata name &lt;index&gt; corresponding to a metadata node with
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]4311 one <tt>i32</tt> entry of value 1. The existence of
Bill Wendlingbc4024f2010-02-25 21:23:24 +0000[diff] [blame]4312 the <tt>!nontemporal</tt> metatadata on the instruction tells the optimizer
4313 and code generator that this load is not expected to be reused in the cache.
4314 The code generator may select special instructions to save cache bandwidth,
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]4315 such as the <tt>MOVNT</tt> instruction on x86.</p>
David Greene9641d062010-02-16 20:50:18 +0000[diff] [blame]4316
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4317<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4318<p>The location of memory pointed to is loaded. If the value being loaded is of
4319 scalar type then the number of bytes read does not exceed the minimum number
4320 of bytes needed to hold all bits of the type. For example, loading an
4321 <tt>i24</tt> reads at most three bytes. When loading a value of a type like
4322 <tt>i20</tt> with a size that is not an integral number of bytes, the result
4323 is undefined if the value was not originally written using a store of the
4324 same type.</p>
4325
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4326<h5>Examples:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4327<pre>
4328 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
4329 <a href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4330 %val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4331</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4332
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4333</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4334
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4335<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]4336<div class="doc_subsubsection"> <a name="i_store">'<tt>store</tt>'
4337Instruction</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4338
Reid Spencera89fb182006-11-09 21:18:01 +0000[diff] [blame]4339<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4340
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4341<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4342<pre>
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]4343 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>
4344 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]4345</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4346
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4347<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4348<p>The '<tt>store</tt>' instruction is used to write to memory.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4349
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4350<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4351<p>There are two arguments to the '<tt>store</tt>' instruction: a value to store
4352 and an address at which to store it. The type of the
4353 '<tt>&lt;pointer&gt;</tt>' operand must be a pointer to
4354 the <a href="#t_firstclass">first class</a> type of the
Jeffrey Yasskin5d284ae2010-04-26 21:21:24 +0000[diff] [blame]4355 '<tt>&lt;value&gt;</tt>' operand. If the <tt>store</tt> is marked as
4356 <tt>volatile</tt>, then the optimizer is not allowed to modify the number or
4357 order of execution of this <tt>store</tt> with other <a
4358 href="#volatile">volatile operations</a>.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4359
4360<p>The optional constant "align" argument specifies the alignment of the
4361 operation (that is, the alignment of the memory address). A value of 0 or an
4362 omitted "align" argument means that the operation has the preferential
4363 alignment for the target. It is the responsibility of the code emitter to
4364 ensure that the alignment information is correct. Overestimating the
4365 alignment results in an undefined behavior. Underestimating the alignment may
4366 produce less efficient code. An alignment of 1 is always safe.</p>
4367
David Greene9641d062010-02-16 20:50:18 +0000[diff] [blame]4368<p>The optional !nontemporal metadata must reference a single metatadata
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]4369 name &lt;index&gt; corresponding to a metadata node with one i32 entry of
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]4370 value 1. The existence of the !nontemporal metatadata on the
David Greene9641d062010-02-16 20:50:18 +0000[diff] [blame]4371 instruction tells the optimizer and code generator that this load is
4372 not expected to be reused in the cache. The code generator may
4373 select special instructions to save cache bandwidth, such as the
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]4374 MOVNT instruction on x86.</p>
David Greene9641d062010-02-16 20:50:18 +0000[diff] [blame]4375
4376
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]4377<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4378<p>The contents of memory are updated to contain '<tt>&lt;value&gt;</tt>' at the
4379 location specified by the '<tt>&lt;pointer&gt;</tt>' operand. If
4380 '<tt>&lt;value&gt;</tt>' is of scalar type then the number of bytes written
4381 does not exceed the minimum number of bytes needed to hold all bits of the
4382 type. For example, storing an <tt>i24</tt> writes at most three bytes. When
4383 writing a value of a type like <tt>i20</tt> with a size that is not an
4384 integral number of bytes, it is unspecified what happens to the extra bits
4385 that do not belong to the type, but they will typically be overwritten.</p>
4386
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4387<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4388<pre>
4389 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Bill Wendling8830ffe2007-10-22 05:10:05 +0000[diff] [blame]4390 store i32 3, i32* %ptr <i>; yields {void}</i>
4391 %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]4392</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4393
Reid Spencer443460a2006-11-09 21:15:49 +0000[diff] [blame]4394</div>
4395
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4396<!-- _______________________________________________________________________ -->
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4397<div class="doc_subsubsection">
4398 <a name="i_getelementptr">'<tt>getelementptr</tt>' Instruction</a>
4399</div>
4400
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4401<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4402
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]4403<h5>Syntax:</h5>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4404<pre>
Matthijs Kooijman0e268272008-10-13 13:44:15 +0000[diff] [blame]4405 &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]4406 &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]4407</pre>
4408
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]4409<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4410<p>The '<tt>getelementptr</tt>' instruction is used to get the address of a
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]4411 subelement of an <a href="#t_aggregate">aggregate</a> data structure.
4412 It performs address calculation only and does not access memory.</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4413
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]4414<h5>Arguments:</h5>
Matthijs Kooijman0e268272008-10-13 13:44:15 +0000[diff] [blame]4415<p>The first argument is always a pointer, and forms the basis of the
Chris Lattnera40b9122009-07-29 06:44:13 +0000[diff] [blame]4416 calculation. The remaining arguments are indices that indicate which of the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4417 elements of the aggregate object are indexed. The interpretation of each
4418 index is dependent on the type being indexed into. The first index always
4419 indexes the pointer value given as the first argument, the second index
4420 indexes a value of the type pointed to (not necessarily the value directly
4421 pointed to, since the first index can be non-zero), etc. The first type
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]4422 indexed into must be a pointer value, subsequent types can be arrays,
4423 vectors, structs and unions. Note that subsequent types being indexed into
4424 can never be pointers, since that would require loading the pointer before
4425 continuing calculation.</p>
Matthijs Kooijman0e268272008-10-13 13:44:15 +0000[diff] [blame]4426
4427<p>The type of each index argument depends on the type it is indexing into.
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]4428 When indexing into a (optionally packed) structure or union, only <tt>i32</tt>
4429 integer <b>constants</b> are allowed. When indexing into an array, pointer
4430 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]4431 constant.</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4432
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4433<p>For example, let's consider a C code fragment and how it gets compiled to
4434 LLVM:</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4435
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]4436<pre class="doc_code">
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]4437struct RT {
4438 char A;
Chris Lattnera446f1b2007-05-29 15:43:56 +0000[diff] [blame]4439 int B[10][20];
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]4440 char C;
4441};
4442struct ST {
Chris Lattnera446f1b2007-05-29 15:43:56 +0000[diff] [blame]4443 int X;
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]4444 double Y;
4445 struct RT Z;
4446};
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4447
Chris Lattnera446f1b2007-05-29 15:43:56 +0000[diff] [blame]4448int *foo(struct ST *s) {
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]4449 return &amp;s[1].Z.B[5][13];
4450}
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4451</pre>
4452
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4453<p>The LLVM code generated by the GCC frontend is:</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4454
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]4455<pre class="doc_code">
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]4456%RT = <a href="#namedtypes">type</a> { i8 , [10 x [20 x i32]], i8 }
4457%ST = <a href="#namedtypes">type</a> { i32, double, %RT }
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4458
Dan Gohman6b867702009-07-25 02:23:48 +0000[diff] [blame]4459define i32* @foo(%ST* %s) {
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]4460entry:
4461 %reg = getelementptr %ST* %s, i32 1, i32 2, i32 1, i32 5, i32 13
4462 ret i32* %reg
4463}
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4464</pre>
4465
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]4466<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4467<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]4468 type, which is a pointer, yielding a '<tt>%ST</tt>' = '<tt>{ i32, double, %RT
4469 }</tt>' type, a structure. The second index indexes into the third element
4470 of the structure, yielding a '<tt>%RT</tt>' = '<tt>{ i8 , [10 x [20 x i32]],
4471 i8 }</tt>' type, another structure. The third index indexes into the second
4472 element of the structure, yielding a '<tt>[10 x [20 x i32]]</tt>' type, an
4473 array. The two dimensions of the array are subscripted into, yielding an
4474 '<tt>i32</tt>' type. The '<tt>getelementptr</tt>' instruction returns a
4475 pointer to this element, thus computing a value of '<tt>i32*</tt>' type.</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4476
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4477<p>Note that it is perfectly legal to index partially through a structure,
4478 returning a pointer to an inner element. Because of this, the LLVM code for
4479 the given testcase is equivalent to:</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4480
4481<pre>
Dan Gohman6b867702009-07-25 02:23:48 +0000[diff] [blame]4482 define i32* @foo(%ST* %s) {
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4483 %t1 = getelementptr %ST* %s, i32 1 <i>; yields %ST*:%t1</i>
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]4484 %t2 = getelementptr %ST* %t1, i32 0, i32 2 <i>; yields %RT*:%t2</i>
4485 %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]4486 %t4 = getelementptr [10 x [20 x i32]]* %t3, i32 0, i32 5 <i>; yields [20 x i32]*:%t4</i>
4487 %t5 = getelementptr [20 x i32]* %t4, i32 0, i32 13 <i>; yields i32*:%t5</i>
4488 ret i32* %t5
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4489 }
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]4490</pre>
Chris Lattnerc0ad71e2005-06-24 17:22:57 +0000[diff] [blame]4491
Dan Gohman1639c392009-07-27 21:53:46 +0000[diff] [blame]4492<p>If the <tt>inbounds</tt> keyword is present, the result value of the
Dan Gohman57255802010-04-23 15:23:32 +0000[diff] [blame]4493 <tt>getelementptr</tt> is a <a href="#trapvalues">trap value</a> if the
4494 base pointer is not an <i>in bounds</i> address of an allocated object,
4495 or if any of the addresses that would be formed by successive addition of
4496 the offsets implied by the indices to the base address with infinitely
4497 precise arithmetic are not an <i>in bounds</i> address of that allocated
4498 object. The <i>in bounds</i> addresses for an allocated object are all
4499 the addresses that point into the object, plus the address one byte past
4500 the end.</p>
Dan Gohman1639c392009-07-27 21:53:46 +0000[diff] [blame]4501
4502<p>If the <tt>inbounds</tt> keyword is not present, the offsets are added to
4503 the base address with silently-wrapping two's complement arithmetic, and
4504 the result value of the <tt>getelementptr</tt> may be outside the object
4505 pointed to by the base pointer. The result value may not necessarily be
4506 used to access memory though, even if it happens to point into allocated
4507 storage. See the <a href="#pointeraliasing">Pointer Aliasing Rules</a>
4508 section for more information.</p>
4509
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4510<p>The getelementptr instruction is often confusing. For some more insight into
4511 how it works, see <a href="GetElementPtr.html">the getelementptr FAQ</a>.</p>
Chris Lattner6ab66722006-08-15 00:45:58 +0000[diff] [blame]4512
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]4513<h5>Example:</h5>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4514<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4515 <i>; yields [12 x i8]*:aptr</i>
Matthijs Kooijman0e268272008-10-13 13:44:15 +0000[diff] [blame]4516 %aptr = getelementptr {i32, [12 x i8]}* %saptr, i64 0, i32 1
4517 <i>; yields i8*:vptr</i>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]4518 %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]4519 <i>; yields i8*:eptr</i>
4520 %eptr = getelementptr [12 x i8]* %aptr, i64 0, i32 1
Sanjiv Gupta0c155e62009-04-25 07:27:44 +0000[diff] [blame]4521 <i>; yields i32*:iptr</i>
Sanjiv Gupta77abea02009-04-24 16:38:13 +0000[diff] [blame]4522 %iptr = getelementptr [10 x i32]* @arr, i16 0, i16 0
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4523</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4524
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4525</div>
Reid Spencer443460a2006-11-09 21:15:49 +0000[diff] [blame]4526
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4527<!-- ======================================================================= -->
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]4528<div class="doc_subsection"> <a name="convertops">Conversion Operations</a>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4529</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4530
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4531<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4532
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]4533<p>The instructions in this category are the conversion instructions (casting)
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4534 which all take a single operand and a type. They perform various bit
4535 conversions on the operand.</p>
4536
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4537</div>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]4538
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]4539<!-- _______________________________________________________________________ -->
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]4540<div class="doc_subsubsection">
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4541 <a name="i_trunc">'<tt>trunc .. to</tt>' Instruction</a>
4542</div>
4543<div class="doc_text">
4544
4545<h5>Syntax:</h5>
4546<pre>
4547 &lt;result&gt; = trunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4548</pre>
4549
4550<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4551<p>The '<tt>trunc</tt>' instruction truncates its operand to the
4552 type <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4553
4554<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4555<p>The '<tt>trunc</tt>' instruction takes a <tt>value</tt> to trunc, which must
4556 be an <a href="#t_integer">integer</a> type, and a type that specifies the
4557 size and type of the result, which must be
4558 an <a href="#t_integer">integer</a> type. The bit size of <tt>value</tt> must
4559 be larger than the bit size of <tt>ty2</tt>. Equal sized types are not
4560 allowed.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4561
4562<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4563<p>The '<tt>trunc</tt>' instruction truncates the high order bits
4564 in <tt>value</tt> and converts the remaining bits to <tt>ty2</tt>. Since the
4565 source size must be larger than the destination size, <tt>trunc</tt> cannot
4566 be a <i>no-op cast</i>. It will always truncate bits.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4567
4568<h5>Example:</h5>
4569<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4570 %X = trunc i32 257 to i8 <i>; yields i8:1</i>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]4571 %Y = trunc i32 123 to i1 <i>; yields i1:true</i>
Gabor Greiff50fd572009-10-28 09:21:30 +0000[diff] [blame]4572 %Z = trunc i32 122 to i1 <i>; yields i1:false</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4573</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4574
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4575</div>
4576
4577<!-- _______________________________________________________________________ -->
4578<div class="doc_subsubsection">
4579 <a name="i_zext">'<tt>zext .. to</tt>' Instruction</a>
4580</div>
4581<div class="doc_text">
4582
4583<h5>Syntax:</h5>
4584<pre>
4585 &lt;result&gt; = zext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4586</pre>
4587
4588<h5>Overview:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4589<p>The '<tt>zext</tt>' instruction zero extends its operand to type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4590 <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4591
4592
4593<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4594<p>The '<tt>zext</tt>' instruction takes a value to cast, which must be of
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4595 <a href="#t_integer">integer</a> type, and a type to cast it to, which must
4596 also be of <a href="#t_integer">integer</a> type. The bit size of the
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4597 <tt>value</tt> must be smaller than the bit size of the destination type,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4598 <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4599
4600<h5>Semantics:</h5>
4601<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]4602 bits until it reaches the size of the destination type, <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4603
Reid Spencer07c9c682007-01-12 15:46:11 +0000[diff] [blame]4604<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]4605
4606<h5>Example:</h5>
4607<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4608 %X = zext i32 257 to i64 <i>; yields i64:257</i>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]4609 %Y = zext i1 true to i32 <i>; yields i32:1</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4610</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4611
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4612</div>
4613
4614<!-- _______________________________________________________________________ -->
4615<div class="doc_subsubsection">
4616 <a name="i_sext">'<tt>sext .. to</tt>' Instruction</a>
4617</div>
4618<div class="doc_text">
4619
4620<h5>Syntax:</h5>
4621<pre>
4622 &lt;result&gt; = sext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4623</pre>
4624
4625<h5>Overview:</h5>
4626<p>The '<tt>sext</tt>' sign extends <tt>value</tt> to the type <tt>ty2</tt>.</p>
4627
4628<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4629<p>The '<tt>sext</tt>' instruction takes a value to cast, which must be of
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4630 <a href="#t_integer">integer</a> type, and a type to cast it to, which must
4631 also be of <a href="#t_integer">integer</a> type. The bit size of the
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4632 <tt>value</tt> must be smaller than the bit size of the destination type,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4633 <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4634
4635<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4636<p>The '<tt>sext</tt>' instruction performs a sign extension by copying the sign
4637 bit (highest order bit) of the <tt>value</tt> until it reaches the bit size
4638 of the type <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4639
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]4640<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]4641
4642<h5>Example:</h5>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4643<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4644 %X = sext i8 -1 to i16 <i>; yields i16 :65535</i>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]4645 %Y = sext i1 true to i32 <i>; yields i32:-1</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4646</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4647
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4648</div>
4649
4650<!-- _______________________________________________________________________ -->
4651<div class="doc_subsubsection">
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]4652 <a name="i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a>
4653</div>
4654
4655<div class="doc_text">
4656
4657<h5>Syntax:</h5>
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]4658<pre>
4659 &lt;result&gt; = fptrunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4660</pre>
4661
4662<h5>Overview:</h5>
4663<p>The '<tt>fptrunc</tt>' instruction truncates <tt>value</tt> to type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4664 <tt>ty2</tt>.</p>
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]4665
4666<h5>Arguments:</h5>
4667<p>The '<tt>fptrunc</tt>' instruction takes a <a href="#t_floating">floating
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4668 point</a> value to cast and a <a href="#t_floating">floating point</a> type
4669 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]4670 <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]4671 <i>no-op cast</i>.</p>
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]4672
4673<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4674<p>The '<tt>fptrunc</tt>' instruction truncates a <tt>value</tt> from a larger
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4675 <a href="#t_floating">floating point</a> type to a smaller
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4676 <a href="#t_floating">floating point</a> type. If the value cannot fit
4677 within the destination type, <tt>ty2</tt>, then the results are
4678 undefined.</p>
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]4679
4680<h5>Example:</h5>
4681<pre>
4682 %X = fptrunc double 123.0 to float <i>; yields float:123.0</i>
4683 %Y = fptrunc double 1.0E+300 to float <i>; yields undefined</i>
4684</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4685
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]4686</div>
4687
4688<!-- _______________________________________________________________________ -->
4689<div class="doc_subsubsection">
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4690 <a name="i_fpext">'<tt>fpext .. to</tt>' Instruction</a>
4691</div>
4692<div class="doc_text">
4693
4694<h5>Syntax:</h5>
4695<pre>
4696 &lt;result&gt; = fpext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4697</pre>
4698
4699<h5>Overview:</h5>
4700<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]4701 floating point value.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4702
4703<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4704<p>The '<tt>fpext</tt>' instruction takes a
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4705 <a href="#t_floating">floating point</a> <tt>value</tt> to cast, and
4706 a <a href="#t_floating">floating point</a> type to cast it to. The source
4707 type must be smaller than the destination type.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4708
4709<h5>Semantics:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]4710<p>The '<tt>fpext</tt>' instruction extends the <tt>value</tt> from a smaller
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4711 <a href="#t_floating">floating point</a> type to a larger
4712 <a href="#t_floating">floating point</a> type. The <tt>fpext</tt> cannot be
4713 used to make a <i>no-op cast</i> because it always changes bits. Use
4714 <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]4715
4716<h5>Example:</h5>
4717<pre>
4718 %X = fpext float 3.1415 to double <i>; yields double:3.1415</i>
4719 %Y = fpext float 1.0 to float <i>; yields float:1.0 (no-op)</i>
4720</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4721
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4722</div>
4723
4724<!-- _______________________________________________________________________ -->
4725<div class="doc_subsubsection">
Reid Spencer2eadb532007-01-21 00:29:26 +0000[diff] [blame]4726 <a name="i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4727</div>
4728<div class="doc_text">
4729
4730<h5>Syntax:</h5>
4731<pre>
Reid Spencer753163d2007-07-31 14:40:14 +0000[diff] [blame]4732 &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]4733</pre>
4734
4735<h5>Overview:</h5>
Reid Spencer753163d2007-07-31 14:40:14 +0000[diff] [blame]4736<p>The '<tt>fptoui</tt>' converts a floating point <tt>value</tt> to its
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4737 unsigned integer equivalent of type <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4738
4739<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4740<p>The '<tt>fptoui</tt>' instruction takes a value to cast, which must be a
4741 scalar or vector <a href="#t_floating">floating point</a> value, and a type
4742 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
4743 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
4744 vector integer type with the same number of elements as <tt>ty</tt></p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4745
4746<h5>Semantics:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4747<p>The '<tt>fptoui</tt>' instruction converts its
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4748 <a href="#t_floating">floating point</a> operand into the nearest (rounding
4749 towards zero) unsigned integer value. If the value cannot fit
4750 in <tt>ty2</tt>, the results are undefined.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4751
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4752<h5>Example:</h5>
4753<pre>
Reid Spencer753163d2007-07-31 14:40:14 +0000[diff] [blame]4754 %X = fptoui double 123.0 to i32 <i>; yields i32:123</i>
Chris Lattner5b95a172007-09-22 03:17:52 +0000[diff] [blame]4755 %Y = fptoui float 1.0E+300 to i1 <i>; yields undefined:1</i>
Gabor Greiff50fd572009-10-28 09:21:30 +0000[diff] [blame]4756 %Z = fptoui float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4757</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4758
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4759</div>
4760
4761<!-- _______________________________________________________________________ -->
4762<div class="doc_subsubsection">
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]4763 <a name="i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4764</div>
4765<div class="doc_text">
4766
4767<h5>Syntax:</h5>
4768<pre>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]4769 &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]4770</pre>
4771
4772<h5>Overview:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4773<p>The '<tt>fptosi</tt>' instruction converts
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4774 <a href="#t_floating">floating point</a> <tt>value</tt> to
4775 type <tt>ty2</tt>.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]4776
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]4777<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4778<p>The '<tt>fptosi</tt>' instruction takes a value to cast, which must be a
4779 scalar or vector <a href="#t_floating">floating point</a> value, and a type
4780 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
4781 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
4782 vector integer type with the same number of elements as <tt>ty</tt></p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]4783
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]4784<h5>Semantics:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4785<p>The '<tt>fptosi</tt>' instruction converts its
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4786 <a href="#t_floating">floating point</a> operand into the nearest (rounding
4787 towards zero) signed integer value. If the value cannot fit in <tt>ty2</tt>,
4788 the results are undefined.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]4789
Chris Lattner70de6632001-07-09 00:26:23 +0000[diff] [blame]4790<h5>Example:</h5>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]4791<pre>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]4792 %X = fptosi double -123.0 to i32 <i>; yields i32:-123</i>
Chris Lattner5b95a172007-09-22 03:17:52 +0000[diff] [blame]4793 %Y = fptosi float 1.0E-247 to i1 <i>; yields undefined:1</i>
Gabor Greiff50fd572009-10-28 09:21:30 +0000[diff] [blame]4794 %Z = fptosi float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4795</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4796
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4797</div>
4798
4799<!-- _______________________________________________________________________ -->
4800<div class="doc_subsubsection">
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]4801 <a name="i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4802</div>
4803<div class="doc_text">
4804
4805<h5>Syntax:</h5>
4806<pre>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]4807 &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]4808</pre>
4809
4810<h5>Overview:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]4811<p>The '<tt>uitofp</tt>' instruction regards <tt>value</tt> as an unsigned
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4812 integer and converts that value to the <tt>ty2</tt> type.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4813
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4814<h5>Arguments:</h5>
Nate Begemand4d45c22007-11-17 03:58:34 +0000[diff] [blame]4815<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]4816 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
4817 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
4818 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
4819 floating point type with the same number of elements as <tt>ty</tt></p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4820
4821<h5>Semantics:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]4822<p>The '<tt>uitofp</tt>' instruction interprets its operand as an unsigned
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4823 integer quantity and converts it to the corresponding floating point
4824 value. If the value cannot fit in the floating point value, the results are
4825 undefined.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4826
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4827<h5>Example:</h5>
4828<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4829 %X = uitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]4830 %Y = uitofp i8 -1 to double <i>; yields double:255.0</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_sitofp">'<tt>sitofp .. 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; = 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]4844</pre>
4845
4846<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4847<p>The '<tt>sitofp</tt>' instruction regards <tt>value</tt> as a signed integer
4848 and converts that value to the <tt>ty2</tt> type.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4849
4850<h5>Arguments:</h5>
Nate Begemand4d45c22007-11-17 03:58:34 +0000[diff] [blame]4851<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]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>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4858<p>The '<tt>sitofp</tt>' instruction interprets its operand as a signed integer
4859 quantity and converts it to the corresponding floating point value. If the
4860 value cannot fit in the floating point value, the results are undefined.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4861
4862<h5>Example:</h5>
4863<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4864 %X = sitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]4865 %Y = sitofp i8 -1 to double <i>; yields double:-1.0</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4866</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4867
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4868</div>
4869
4870<!-- _______________________________________________________________________ -->
4871<div class="doc_subsubsection">
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]4872 <a name="i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a>
4873</div>
4874<div class="doc_text">
4875
4876<h5>Syntax:</h5>
4877<pre>
4878 &lt;result&gt; = ptrtoint &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4879</pre>
4880
4881<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4882<p>The '<tt>ptrtoint</tt>' instruction converts the pointer <tt>value</tt> to
4883 the integer type <tt>ty2</tt>.</p>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]4884
4885<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4886<p>The '<tt>ptrtoint</tt>' instruction takes a <tt>value</tt> to cast, which
4887 must be a <a href="#t_pointer">pointer</a> value, and a type to cast it to
4888 <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]4889
4890<h5>Semantics:</h5>
4891<p>The '<tt>ptrtoint</tt>' instruction converts <tt>value</tt> to integer type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4892 <tt>ty2</tt> by interpreting the pointer value as an integer and either
4893 truncating or zero extending that value to the size of the integer type. If
4894 <tt>value</tt> is smaller than <tt>ty2</tt> then a zero extension is done. If
4895 <tt>value</tt> is larger than <tt>ty2</tt> then a truncation is done. If they
4896 are the same size, then nothing is done (<i>no-op cast</i>) other than a type
4897 change.</p>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]4898
4899<h5>Example:</h5>
4900<pre>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]4901 %X = ptrtoint i32* %X to i8 <i>; yields truncation on 32-bit architecture</i>
4902 %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]4903</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4904
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]4905</div>
4906
4907<!-- _______________________________________________________________________ -->
4908<div class="doc_subsubsection">
4909 <a name="i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a>
4910</div>
4911<div class="doc_text">
4912
4913<h5>Syntax:</h5>
4914<pre>
4915 &lt;result&gt; = inttoptr &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4916</pre>
4917
4918<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4919<p>The '<tt>inttoptr</tt>' instruction converts an integer <tt>value</tt> to a
4920 pointer type, <tt>ty2</tt>.</p>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]4921
4922<h5>Arguments:</h5>
Duncan Sands16f122e2007-03-30 12:22:09 +0000[diff] [blame]4923<p>The '<tt>inttoptr</tt>' instruction takes an <a href="#t_integer">integer</a>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4924 value to cast, and a type to cast it to, which must be a
4925 <a href="#t_pointer">pointer</a> type.</p>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]4926
4927<h5>Semantics:</h5>
4928<p>The '<tt>inttoptr</tt>' instruction converts <tt>value</tt> to type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4929 <tt>ty2</tt> by applying either a zero extension or a truncation depending on
4930 the size of the integer <tt>value</tt>. If <tt>value</tt> is larger than the
4931 size of a pointer then a truncation is done. If <tt>value</tt> is smaller
4932 than the size of a pointer then a zero extension is done. If they are the
4933 same size, nothing is done (<i>no-op cast</i>).</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 = inttoptr i32 255 to i32* <i>; yields zero extension on 64-bit architecture</i>
Gabor Greiff50fd572009-10-28 09:21:30 +0000[diff] [blame]4938 %Y = inttoptr i32 255 to i32* <i>; yields no-op on 32-bit architecture</i>
4939 %Z = inttoptr i64 0 to i32* <i>; yields truncation on 32-bit architecture</i>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]4940</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4941
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]4942</div>
4943
4944<!-- _______________________________________________________________________ -->
4945<div class="doc_subsubsection">
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]4946 <a name="i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4947</div>
4948<div class="doc_text">
4949
4950<h5>Syntax:</h5>
4951<pre>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]4952 &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]4953</pre>
4954
4955<h5>Overview:</h5>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]4956<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4957 <tt>ty2</tt> without changing any bits.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4958
4959<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4960<p>The '<tt>bitcast</tt>' instruction takes a value to cast, which must be a
4961 non-aggregate first class value, and a type to cast it to, which must also be
4962 a non-aggregate <a href="#t_firstclass">first class</a> type. The bit sizes
4963 of <tt>value</tt> and the destination type, <tt>ty2</tt>, must be
4964 identical. If the source type is a pointer, the destination type must also be
4965 a pointer. This instruction supports bitwise conversion of vectors to
4966 integers and to vectors of other types (as long as they have the same
4967 size).</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4968
4969<h5>Semantics:</h5>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]4970<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4971 <tt>ty2</tt>. It is always a <i>no-op cast</i> because no bits change with
4972 this conversion. The conversion is done as if the <tt>value</tt> had been
4973 stored to memory and read back as type <tt>ty2</tt>. Pointer types may only
4974 be converted to other pointer types with this instruction. To convert
4975 pointers to other types, use the <a href="#i_inttoptr">inttoptr</a> or
4976 <a href="#i_ptrtoint">ptrtoint</a> instructions first.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4977
4978<h5>Example:</h5>
4979<pre>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]4980 %X = bitcast i8 255 to i8 <i>; yields i8 :-1</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4981 %Y = bitcast i32* %x to sint* <i>; yields sint*:%x</i>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4982 %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]4983</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4984
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4985</div>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]4986
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]4987<!-- ======================================================================= -->
4988<div class="doc_subsection"> <a name="otherops">Other Operations</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4989
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]4990<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4991
4992<p>The instructions in this category are the "miscellaneous" instructions, which
4993 defy better classification.</p>
4994
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]4995</div>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4996
4997<!-- _______________________________________________________________________ -->
4998<div class="doc_subsubsection"><a name="i_icmp">'<tt>icmp</tt>' Instruction</a>
4999</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5000
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5001<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5002
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5003<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5004<pre>
5005 &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]5006</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5007
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5008<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5009<p>The '<tt>icmp</tt>' instruction returns a boolean value or a vector of
5010 boolean values based on comparison of its two integer, integer vector, or
5011 pointer operands.</p>
5012
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5013<h5>Arguments:</h5>
5014<p>The '<tt>icmp</tt>' instruction takes three operands. The first operand is
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5015 the condition code indicating the kind of comparison to perform. It is not a
5016 value, just a keyword. The possible condition code are:</p>
5017
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5018<ol>
5019 <li><tt>eq</tt>: equal</li>
5020 <li><tt>ne</tt>: not equal </li>
5021 <li><tt>ugt</tt>: unsigned greater than</li>
5022 <li><tt>uge</tt>: unsigned greater or equal</li>
5023 <li><tt>ult</tt>: unsigned less than</li>
5024 <li><tt>ule</tt>: unsigned less or equal</li>
5025 <li><tt>sgt</tt>: signed greater than</li>
5026 <li><tt>sge</tt>: signed greater or equal</li>
5027 <li><tt>slt</tt>: signed less than</li>
5028 <li><tt>sle</tt>: signed less or equal</li>
5029</ol>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5030
Chris Lattnerc0f423a2007-01-15 01:54:13 +0000[diff] [blame]5031<p>The remaining two arguments must be <a href="#t_integer">integer</a> or
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5032 <a href="#t_pointer">pointer</a> or integer <a href="#t_vector">vector</a>
5033 typed. They must also be identical types.</p>
5034
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5035<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5036<p>The '<tt>icmp</tt>' compares <tt>op1</tt> and <tt>op2</tt> according to the
5037 condition code given as <tt>cond</tt>. The comparison performed always yields
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]5038 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]5039 result, as follows:</p>
5040
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5041<ol>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5042 <li><tt>eq</tt>: yields <tt>true</tt> if the operands are equal,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5043 <tt>false</tt> otherwise. No sign interpretation is necessary or
5044 performed.</li>
5045
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5046 <li><tt>ne</tt>: yields <tt>true</tt> if the operands are unequal,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5047 <tt>false</tt> otherwise. No sign interpretation is necessary or
5048 performed.</li>
5049
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5050 <li><tt>ugt</tt>: interprets the operands as unsigned values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5051 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
5052
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5053 <li><tt>uge</tt>: interprets the operands as unsigned values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5054 <tt>true</tt> if <tt>op1</tt> is greater than or equal
5055 to <tt>op2</tt>.</li>
5056
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5057 <li><tt>ult</tt>: interprets the operands as unsigned values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5058 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
5059
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5060 <li><tt>ule</tt>: interprets the operands as unsigned values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5061 <tt>true</tt> if <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
5062
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5063 <li><tt>sgt</tt>: interprets the operands as signed values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5064 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
5065
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5066 <li><tt>sge</tt>: interprets the operands as signed values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5067 <tt>true</tt> if <tt>op1</tt> is greater than or equal
5068 to <tt>op2</tt>.</li>
5069
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5070 <li><tt>slt</tt>: interprets the operands as signed values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5071 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
5072
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5073 <li><tt>sle</tt>: interprets the operands as signed values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5074 <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]5075</ol>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5076
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5077<p>If the operands are <a href="#t_pointer">pointer</a> typed, the pointer
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5078 values are compared as if they were integers.</p>
5079
5080<p>If the operands are integer vectors, then they are compared element by
5081 element. The result is an <tt>i1</tt> vector with the same number of elements
5082 as the values being compared. Otherwise, the result is an <tt>i1</tt>.</p>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5083
5084<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5085<pre>
5086 &lt;result&gt; = icmp eq i32 4, 5 <i>; yields: result=false</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]5087 &lt;result&gt; = icmp ne float* %X, %X <i>; yields: result=false</i>
5088 &lt;result&gt; = icmp ult i16 4, 5 <i>; yields: result=true</i>
5089 &lt;result&gt; = icmp sgt i16 4, 5 <i>; yields: result=false</i>
5090 &lt;result&gt; = icmp ule i16 -4, 5 <i>; yields: result=false</i>
5091 &lt;result&gt; = icmp sge i16 4, 5 <i>; yields: result=false</i>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5092</pre>
Dan Gohmana5127ab2009-01-22 01:39:38 +0000[diff] [blame]5093
5094<p>Note that the code generator does not yet support vector types with
5095 the <tt>icmp</tt> instruction.</p>
5096
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5097</div>
5098
5099<!-- _______________________________________________________________________ -->
5100<div class="doc_subsubsection"><a name="i_fcmp">'<tt>fcmp</tt>' Instruction</a>
5101</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5102
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5103<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5104
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5105<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5106<pre>
5107 &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]5108</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5109
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5110<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5111<p>The '<tt>fcmp</tt>' instruction returns a boolean value or vector of boolean
5112 values based on comparison of its operands.</p>
5113
5114<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]5115(<a href="#t_integer"><tt>i1</tt></a>).</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5116
5117<p>If the operands are floating point vectors, then the result type is a vector
5118 of boolean with the same number of elements as the operands being
5119 compared.</p>
5120
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5121<h5>Arguments:</h5>
5122<p>The '<tt>fcmp</tt>' instruction takes three operands. The first operand is
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5123 the condition code indicating the kind of comparison to perform. It is not a
5124 value, just a keyword. The possible condition code are:</p>
5125
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5126<ol>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]5127 <li><tt>false</tt>: no comparison, always returns false</li>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5128 <li><tt>oeq</tt>: ordered and equal</li>
5129 <li><tt>ogt</tt>: ordered and greater than </li>
5130 <li><tt>oge</tt>: ordered and greater than or equal</li>
5131 <li><tt>olt</tt>: ordered and less than </li>
5132 <li><tt>ole</tt>: ordered and less than or equal</li>
5133 <li><tt>one</tt>: ordered and not equal</li>
5134 <li><tt>ord</tt>: ordered (no nans)</li>
5135 <li><tt>ueq</tt>: unordered or equal</li>
5136 <li><tt>ugt</tt>: unordered or greater than </li>
5137 <li><tt>uge</tt>: unordered or greater than or equal</li>
5138 <li><tt>ult</tt>: unordered or less than </li>
5139 <li><tt>ule</tt>: unordered or less than or equal</li>
5140 <li><tt>une</tt>: unordered or not equal</li>
5141 <li><tt>uno</tt>: unordered (either nans)</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]5142 <li><tt>true</tt>: no comparison, always returns true</li>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5143</ol>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5144
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5145<p><i>Ordered</i> means that neither operand is a QNAN while
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5146 <i>unordered</i> means that either operand may be a QNAN.</p>
5147
5148<p>Each of <tt>val1</tt> and <tt>val2</tt> arguments must be either
5149 a <a href="#t_floating">floating point</a> type or
5150 a <a href="#t_vector">vector</a> of floating point type. They must have
5151 identical types.</p>
5152
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5153<h5>Semantics:</h5>
Gabor Greif0f75ad02008-08-07 21:46:00 +0000[diff] [blame]5154<p>The '<tt>fcmp</tt>' instruction compares <tt>op1</tt> and <tt>op2</tt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5155 according to the condition code given as <tt>cond</tt>. If the operands are
5156 vectors, then the vectors are compared element by element. Each comparison
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]5157 performed always yields an <a href="#t_integer">i1</a> result, as
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5158 follows:</p>
5159
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5160<ol>
5161 <li><tt>false</tt>: always yields <tt>false</tt>, regardless of operands.</li>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5162
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5163 <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]5164 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
5165
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]5166 <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]5167 <tt>op1</tt> is greater than <tt>op2</tt>.</li>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5168
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5169 <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]5170 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
5171
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5172 <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]5173 <tt>op1</tt> is less than <tt>op2</tt>.</li>
5174
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5175 <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]5176 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
5177
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5178 <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]5179 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
5180
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]5181 <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]5182
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5183 <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]5184 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
5185
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5186 <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]5187 <tt>op1</tt> is greater than <tt>op2</tt>.</li>
5188
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5189 <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]5190 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
5191
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5192 <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]5193 <tt>op1</tt> is less than <tt>op2</tt>.</li>
5194
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5195 <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]5196 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
5197
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5198 <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]5199 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
5200
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]5201 <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]5202
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5203 <li><tt>true</tt>: always yields <tt>true</tt>, regardless of operands.</li>
5204</ol>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5205
5206<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5207<pre>
5208 &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]5209 &lt;result&gt; = fcmp one float 4.0, 5.0 <i>; yields: result=true</i>
5210 &lt;result&gt; = fcmp olt float 4.0, 5.0 <i>; yields: result=true</i>
5211 &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]5212</pre>
Dan Gohmana5127ab2009-01-22 01:39:38 +0000[diff] [blame]5213
5214<p>Note that the code generator does not yet support vector types with
5215 the <tt>fcmp</tt> instruction.</p>
5216
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5217</div>
5218
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5219<!-- _______________________________________________________________________ -->
Nate Begemand2195702008-05-12 19:01:56 +0000[diff] [blame]5220<div class="doc_subsubsection">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]5221 <a name="i_phi">'<tt>phi</tt>' Instruction</a>
5222</div>
5223
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5224<div class="doc_text">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]5225
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5226<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5227<pre>
5228 &lt;result&gt; = phi &lt;ty&gt; [ &lt;val0&gt;, &lt;label0&gt;], ...
5229</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]5230
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5231<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5232<p>The '<tt>phi</tt>' instruction is used to implement the &#966; node in the
5233 SSA graph representing the function.</p>
5234
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5235<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5236<p>The type of the incoming values is specified with the first type field. After
5237 this, the '<tt>phi</tt>' instruction takes a list of pairs as arguments, with
5238 one pair for each predecessor basic block of the current block. Only values
5239 of <a href="#t_firstclass">first class</a> type may be used as the value
5240 arguments to the PHI node. Only labels may be used as the label
5241 arguments.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]5242
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5243<p>There must be no non-phi instructions between the start of a basic block and
5244 the PHI instructions: i.e. PHI instructions must be first in a basic
5245 block.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]5246
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5247<p>For the purposes of the SSA form, the use of each incoming value is deemed to
5248 occur on the edge from the corresponding predecessor block to the current
5249 block (but after any definition of an '<tt>invoke</tt>' instruction's return
5250 value on the same edge).</p>
Jay Foad1a4eea52009-06-03 10:20:10 +0000[diff] [blame]5251
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5252<h5>Semantics:</h5>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5253<p>At runtime, the '<tt>phi</tt>' instruction logically takes on the value
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5254 specified by the pair corresponding to the predecessor basic block that
5255 executed just prior to the current block.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]5256
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5257<h5>Example:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]5258<pre>
5259Loop: ; Infinite loop that counts from 0 on up...
5260 %indvar = phi i32 [ 0, %LoopHeader ], [ %nextindvar, %Loop ]
5261 %nextindvar = add i32 %indvar, 1
5262 br label %Loop
5263</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5264
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5265</div>
5266
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5267<!-- _______________________________________________________________________ -->
5268<div class="doc_subsubsection">
5269 <a name="i_select">'<tt>select</tt>' Instruction</a>
5270</div>
5271
5272<div class="doc_text">
5273
5274<h5>Syntax:</h5>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5275<pre>
Dan Gohmanc579d972008-09-09 01:02:47 +0000[diff] [blame]5276 &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>
5277
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]5278 <i>selty</i> is either i1 or {&lt;N x i1&gt;}
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5279</pre>
5280
5281<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5282<p>The '<tt>select</tt>' instruction is used to choose one value based on a
5283 condition, without branching.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5284
5285
5286<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5287<p>The '<tt>select</tt>' instruction requires an 'i1' value or a vector of 'i1'
5288 values indicating the condition, and two values of the
5289 same <a href="#t_firstclass">first class</a> type. If the val1/val2 are
5290 vectors and the condition is a scalar, then entire vectors are selected, not
5291 individual elements.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5292
5293<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5294<p>If the condition is an i1 and it evaluates to 1, the instruction returns the
5295 first value argument; otherwise, it returns the second value argument.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5296
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5297<p>If the condition is a vector of i1, then the value arguments must be vectors
5298 of the same size, and the selection is done element by element.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5299
5300<h5>Example:</h5>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5301<pre>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]5302 %X = select i1 true, i8 17, i8 42 <i>; yields i8:17</i>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5303</pre>
Dan Gohmana5127ab2009-01-22 01:39:38 +0000[diff] [blame]5304
5305<p>Note that the code generator does not yet support conditions
5306 with vector type.</p>
5307
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5308</div>
5309
Robert Bocchinof72fdfe2006-01-15 20:48:27 +0000[diff] [blame]5310<!-- _______________________________________________________________________ -->
5311<div class="doc_subsubsection">
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5312 <a name="i_call">'<tt>call</tt>' Instruction</a>
5313</div>
5314
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5315<div class="doc_text">
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5316
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]5317<h5>Syntax:</h5>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5318<pre>
Devang Patel02256232008-10-07 17:48:33 +0000[diff] [blame]5319 &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]5320</pre>
5321
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]5322<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5323<p>The '<tt>call</tt>' instruction represents a simple function call.</p>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5324
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]5325<h5>Arguments:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5326<p>This instruction requires several arguments:</p>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5327
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]5328<ol>
Jeffrey Yasskinb8677462010-01-09 19:44:16 +0000[diff] [blame]5329 <li>The optional "tail" marker indicates that the callee function does not
5330 access any allocas or varargs in the caller. Note that calls may be
5331 marked "tail" even if they do not occur before
5332 a <a href="#i_ret"><tt>ret</tt></a> instruction. If the "tail" marker is
5333 present, the function call is eligible for tail call optimization,
5334 but <a href="CodeGenerator.html#tailcallopt">might not in fact be
Evan Cheng59676492010-03-08 21:05:02 +0000[diff] [blame]5335 optimized into a jump</a>. The code generator may optimize calls marked
5336 "tail" with either 1) automatic <a href="CodeGenerator.html#sibcallopt">
5337 sibling call optimization</a> when the caller and callee have
5338 matching signatures, or 2) forced tail call optimization when the
5339 following extra requirements are met:
Jeffrey Yasskinb8677462010-01-09 19:44:16 +0000[diff] [blame]5340 <ul>
5341 <li>Caller and callee both have the calling
5342 convention <tt>fastcc</tt>.</li>
5343 <li>The call is in tail position (ret immediately follows call and ret
5344 uses value of call or is void).</li>
5345 <li>Option <tt>-tailcallopt</tt> is enabled,
Dan Gohman6232f732010-03-02 01:08:11 +0000[diff] [blame]5346 or <code>llvm::GuaranteedTailCallOpt</code> is <code>true</code>.</li>
Jeffrey Yasskinb8677462010-01-09 19:44:16 +0000[diff] [blame]5347 <li><a href="CodeGenerator.html#tailcallopt">Platform specific
5348 constraints are met.</a></li>
5349 </ul>
5350 </li>
Devang Patel7e9b05e2008-10-06 18:50:38 +0000[diff] [blame]5351
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5352 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
5353 convention</a> the call should use. If none is specified, the call
Jeffrey Yasskinb8677462010-01-09 19:44:16 +0000[diff] [blame]5354 defaults to using C calling conventions. The calling convention of the
5355 call must match the calling convention of the target function, or else the
5356 behavior is undefined.</li>
Devang Patel7e9b05e2008-10-06 18:50:38 +0000[diff] [blame]5357
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5358 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
5359 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
5360 '<tt>inreg</tt>' attributes are valid here.</li>
5361
5362 <li>'<tt>ty</tt>': the type of the call instruction itself which is also the
5363 type of the return value. Functions that return no value are marked
5364 <tt><a href="#t_void">void</a></tt>.</li>
5365
5366 <li>'<tt>fnty</tt>': shall be the signature of the pointer to function value
5367 being invoked. The argument types must match the types implied by this
5368 signature. This type can be omitted if the function is not varargs and if
5369 the function type does not return a pointer to a function.</li>
5370
5371 <li>'<tt>fnptrval</tt>': An LLVM value containing a pointer to a function to
5372 be invoked. In most cases, this is a direct function invocation, but
5373 indirect <tt>call</tt>s are just as possible, calling an arbitrary pointer
5374 to function value.</li>
5375
5376 <li>'<tt>function args</tt>': argument list whose types match the function
Chris Lattner47f2a832010-03-02 06:36:51 +0000[diff] [blame]5377 signature argument types and parameter attributes. All arguments must be
5378 of <a href="#t_firstclass">first class</a> type. If the function
5379 signature indicates the function accepts a variable number of arguments,
5380 the extra arguments can be specified.</li>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5381
5382 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
5383 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
5384 '<tt>readnone</tt>' attributes are valid here.</li>
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]5385</ol>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5386
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]5387<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5388<p>The '<tt>call</tt>' instruction is used to cause control flow to transfer to
5389 a specified function, with its incoming arguments bound to the specified
5390 values. Upon a '<tt><a href="#i_ret">ret</a></tt>' instruction in the called
5391 function, control flow continues with the instruction after the function
5392 call, and the return value of the function is bound to the result
5393 argument.</p>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5394
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]5395<h5>Example:</h5>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5396<pre>
Nick Lewyckya9b13d52007-09-08 13:57:50 +0000[diff] [blame]5397 %retval = call i32 @test(i32 %argc)
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]5398 call i32 (i8*, ...)* @printf(i8* %msg, i32 12, i8 42) <i>; yields i32</i>
Chris Lattnerfb7c88d2008-03-21 17:24:17 +0000[diff] [blame]5399 %X = tail call i32 @foo() <i>; yields i32</i>
5400 %Y = tail call <a href="#callingconv">fastcc</a> i32 @foo() <i>; yields i32</i>
5401 call void %foo(i8 97 signext)
Devang Pateld6cff512008-03-10 20:49:15 +0000[diff] [blame]5402
5403 %struct.A = type { i32, i8 }
Devang Patel7e9b05e2008-10-06 18:50:38 +0000[diff] [blame]5404 %r = call %struct.A @foo() <i>; yields { 32, i8 }</i>
Dan Gohmancc3132e2008-10-04 19:00:07 +0000[diff] [blame]5405 %gr = extractvalue %struct.A %r, 0 <i>; yields i32</i>
5406 %gr1 = extractvalue %struct.A %r, 1 <i>; yields i8</i>
Chris Lattner6cbe8e92008-10-08 06:26:11 +0000[diff] [blame]5407 %Z = call void @foo() noreturn <i>; indicates that %foo never returns normally</i>
Matthijs Kooijmaneefa7df2008-10-07 10:03:45 +0000[diff] [blame]5408 %ZZ = call zeroext i32 @bar() <i>; Return value is %zero extended</i>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5409</pre>
5410
Dale Johannesen68f971b2009-09-24 18:38:21 +0000[diff] [blame]5411<p>llvm treats calls to some functions with names and arguments that match the
Dale Johannesen722212d2009-09-25 17:04:42 +0000[diff] [blame]5412standard C99 library as being the C99 library functions, and may perform
5413optimizations or generate code for them under that assumption. This is
5414something we'd like to change in the future to provide better support for
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]5415freestanding environments and non-C-based languages.</p>
Dale Johannesen68f971b2009-09-24 18:38:21 +0000[diff] [blame]5416
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5417</div>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5418
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5419<!-- _______________________________________________________________________ -->
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5420<div class="doc_subsubsection">
Chris Lattner33337472006-01-13 23:26:01 +0000[diff] [blame]5421 <a name="i_va_arg">'<tt>va_arg</tt>' Instruction</a>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5422</div>
5423
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5424<div class="doc_text">
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5425
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]5426<h5>Syntax:</h5>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5427<pre>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]5428 &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]5429</pre>
5430
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]5431<h5>Overview:</h5>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]5432<p>The '<tt>va_arg</tt>' instruction is used to access arguments passed through
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5433 the "variable argument" area of a function call. It is used to implement the
5434 <tt>va_arg</tt> macro in C.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5435
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]5436<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5437<p>This instruction takes a <tt>va_list*</tt> value and the type of the
5438 argument. It returns a value of the specified argument type and increments
5439 the <tt>va_list</tt> to point to the next argument. The actual type
5440 of <tt>va_list</tt> is target specific.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5441
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]5442<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5443<p>The '<tt>va_arg</tt>' instruction loads an argument of the specified type
5444 from the specified <tt>va_list</tt> and causes the <tt>va_list</tt> to point
5445 to the next argument. For more information, see the variable argument
5446 handling <a href="#int_varargs">Intrinsic Functions</a>.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5447
5448<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]5449 take a variable number of arguments, for example, the <tt>vfprintf</tt>
5450 function.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5451
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5452<p><tt>va_arg</tt> is an LLVM instruction instead of
5453 an <a href="#intrinsics">intrinsic function</a> because it takes a type as an
5454 argument.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5455
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]5456<h5>Example:</h5>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5457<p>See the <a href="#int_varargs">variable argument processing</a> section.</p>
5458
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5459<p>Note that the code generator does not yet fully support va_arg on many
5460 targets. Also, it does not currently support va_arg with aggregate types on
5461 any target.</p>
Dan Gohman3065b612009-01-12 23:12:39 +0000[diff] [blame]5462
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5463</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5464
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5465<!-- *********************************************************************** -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]5466<div class="doc_section"> <a name="intrinsics">Intrinsic Functions</a> </div>
5467<!-- *********************************************************************** -->
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5468
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5469<div class="doc_text">
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5470
5471<p>LLVM supports the notion of an "intrinsic function". These functions have
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5472 well known names and semantics and are required to follow certain
5473 restrictions. Overall, these intrinsics represent an extension mechanism for
5474 the LLVM language that does not require changing all of the transformations
5475 in LLVM when adding to the language (or the bitcode reader/writer, the
5476 parser, etc...).</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5477
John Criswell88190562005-05-16 16:17:45 +0000[diff] [blame]5478<p>Intrinsic function names must all start with an "<tt>llvm.</tt>" prefix. This
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5479 prefix is reserved in LLVM for intrinsic names; thus, function names may not
5480 begin with this prefix. Intrinsic functions must always be external
5481 functions: you cannot define the body of intrinsic functions. Intrinsic
5482 functions may only be used in call or invoke instructions: it is illegal to
5483 take the address of an intrinsic function. Additionally, because intrinsic
5484 functions are part of the LLVM language, it is required if any are added that
5485 they be documented here.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5486
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5487<p>Some intrinsic functions can be overloaded, i.e., the intrinsic represents a
5488 family of functions that perform the same operation but on different data
5489 types. Because LLVM can represent over 8 million different integer types,
5490 overloading is used commonly to allow an intrinsic function to operate on any
5491 integer type. One or more of the argument types or the result type can be
5492 overloaded to accept any integer type. Argument types may also be defined as
5493 exactly matching a previous argument's type or the result type. This allows
5494 an intrinsic function which accepts multiple arguments, but needs all of them
5495 to be of the same type, to only be overloaded with respect to a single
5496 argument or the result.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5497
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5498<p>Overloaded intrinsics will have the names of its overloaded argument types
5499 encoded into its function name, each preceded by a period. Only those types
5500 which are overloaded result in a name suffix. Arguments whose type is matched
5501 against another type do not. For example, the <tt>llvm.ctpop</tt> function
5502 can take an integer of any width and returns an integer of exactly the same
5503 integer width. This leads to a family of functions such as
5504 <tt>i8 @llvm.ctpop.i8(i8 %val)</tt> and <tt>i29 @llvm.ctpop.i29(i29
5505 %val)</tt>. Only one type, the return type, is overloaded, and only one type
5506 suffix is required. Because the argument's type is matched against the return
5507 type, it does not require its own name suffix.</p>
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]5508
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5509<p>To learn how to add an intrinsic function, please see the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5510 <a href="ExtendingLLVM.html">Extending LLVM Guide</a>.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5511
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5512</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5513
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5514<!-- ======================================================================= -->
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5515<div class="doc_subsection">
5516 <a name="int_varargs">Variable Argument Handling Intrinsics</a>
5517</div>
5518
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5519<div class="doc_text">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5520
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5521<p>Variable argument support is defined in LLVM with
5522 the <a href="#i_va_arg"><tt>va_arg</tt></a> instruction and these three
5523 intrinsic functions. These functions are related to the similarly named
5524 macros defined in the <tt>&lt;stdarg.h&gt;</tt> header file.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5525
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5526<p>All of these functions operate on arguments that use a target-specific value
5527 type "<tt>va_list</tt>". The LLVM assembly language reference manual does
5528 not define what this type is, so all transformations should be prepared to
5529 handle these functions regardless of the type used.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5530
Chris Lattner30b868d2006-05-15 17:26:46 +0000[diff] [blame]5531<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]5532 instruction and the variable argument handling intrinsic functions are
5533 used.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5534
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]5535<pre class="doc_code">
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]5536define i32 @test(i32 %X, ...) {
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5537 ; Initialize variable argument processing
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5538 %ap = alloca i8*
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]5539 %ap2 = bitcast i8** %ap to i8*
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]5540 call void @llvm.va_start(i8* %ap2)
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5541
5542 ; Read a single integer argument
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5543 %tmp = va_arg i8** %ap, i32
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5544
5545 ; Demonstrate usage of llvm.va_copy and llvm.va_end
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5546 %aq = alloca i8*
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]5547 %aq2 = bitcast i8** %aq to i8*
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5548 call void @llvm.va_copy(i8* %aq2, i8* %ap2)
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]5549 call void @llvm.va_end(i8* %aq2)
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5550
5551 ; Stop processing of arguments.
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]5552 call void @llvm.va_end(i8* %ap2)
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]5553 ret i32 %tmp
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5554}
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]5555
5556declare void @llvm.va_start(i8*)
5557declare void @llvm.va_copy(i8*, i8*)
5558declare void @llvm.va_end(i8*)
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5559</pre>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5560
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]5561</div>
5562
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5563<!-- _______________________________________________________________________ -->
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5564<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5565 <a name="int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5566</div>
5567
5568
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5569<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5570
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5571<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5572<pre>
5573 declare void %llvm.va_start(i8* &lt;arglist&gt;)
5574</pre>
5575
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5576<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5577<p>The '<tt>llvm.va_start</tt>' intrinsic initializes <tt>*&lt;arglist&gt;</tt>
5578 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]5579
5580<h5>Arguments:</h5>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]5581<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]5582
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5583<h5>Semantics:</h5>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]5584<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]5585 macro available in C. In a target-dependent way, it initializes
5586 the <tt>va_list</tt> element to which the argument points, so that the next
5587 call to <tt>va_arg</tt> will produce the first variable argument passed to
5588 the function. Unlike the C <tt>va_start</tt> macro, this intrinsic does not
5589 need to know the last argument of the function as the compiler can figure
5590 that out.</p>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]5591
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5592</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5593
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5594<!-- _______________________________________________________________________ -->
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5595<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5596 <a name="int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5597</div>
5598
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5599<div class="doc_text">
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]5600
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5601<h5>Syntax:</h5>
5602<pre>
5603 declare void @llvm.va_end(i8* &lt;arglist&gt;)
5604</pre>
5605
5606<h5>Overview:</h5>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5607<p>The '<tt>llvm.va_end</tt>' intrinsic destroys <tt>*&lt;arglist&gt;</tt>,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5608 which has been initialized previously
5609 with <tt><a href="#int_va_start">llvm.va_start</a></tt>
5610 or <tt><a href="#i_va_copy">llvm.va_copy</a></tt>.</p>
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]5611
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5612<h5>Arguments:</h5>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5613<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]5614
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5615<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5616<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]5617 macro available in C. In a target-dependent way, it destroys
5618 the <tt>va_list</tt> element to which the argument points. Calls
5619 to <a href="#int_va_start"><tt>llvm.va_start</tt></a>
5620 and <a href="#int_va_copy"> <tt>llvm.va_copy</tt></a> must be matched exactly
5621 with calls to <tt>llvm.va_end</tt>.</p>
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]5622
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5623</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5624
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5625<!-- _______________________________________________________________________ -->
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5626<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5627 <a name="int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5628</div>
5629
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5630<div class="doc_text">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5631
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5632<h5>Syntax:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5633<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]5634 declare void @llvm.va_copy(i8* &lt;destarglist&gt;, i8* &lt;srcarglist&gt;)
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5635</pre>
5636
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5637<h5>Overview:</h5>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5638<p>The '<tt>llvm.va_copy</tt>' intrinsic copies the current argument position
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5639 from the source argument list to the destination argument list.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5640
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5641<h5>Arguments:</h5>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]5642<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]5643 The second argument is a pointer to a <tt>va_list</tt> element to copy
5644 from.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5645
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5646<h5>Semantics:</h5>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5647<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]5648 macro available in C. In a target-dependent way, it copies the
5649 source <tt>va_list</tt> element into the destination <tt>va_list</tt>
5650 element. This intrinsic is necessary because
5651 the <tt><a href="#int_va_start"> llvm.va_start</a></tt> intrinsic may be
5652 arbitrarily complex and require, for example, memory allocation.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5653
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5654</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5655
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5656<!-- ======================================================================= -->
5657<div class="doc_subsection">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5658 <a name="int_gc">Accurate Garbage Collection Intrinsics</a>
5659</div>
5660
5661<div class="doc_text">
5662
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5663<p>LLVM support for <a href="GarbageCollection.html">Accurate Garbage
Chris Lattner67c37d12008-08-05 18:29:16 +0000[diff] [blame]5664Collection</a> (GC) requires the implementation and generation of these
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5665intrinsics. These intrinsics allow identification of <a href="#int_gcroot">GC
5666roots on the stack</a>, as well as garbage collector implementations that
5667require <a href="#int_gcread">read</a> and <a href="#int_gcwrite">write</a>
5668barriers. Front-ends for type-safe garbage collected languages should generate
5669these intrinsics to make use of the LLVM garbage collectors. For more details,
5670see <a href="GarbageCollection.html">Accurate Garbage Collection with
5671LLVM</a>.</p>
Christopher Lamb55c6d4f2007-12-17 01:00:21 +0000[diff] [blame]5672
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5673<p>The garbage collection intrinsics only operate on objects in the generic
5674 address space (address space zero).</p>
Christopher Lamb55c6d4f2007-12-17 01:00:21 +0000[diff] [blame]5675
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5676</div>
5677
5678<!-- _______________________________________________________________________ -->
5679<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5680 <a name="int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5681</div>
5682
5683<div class="doc_text">
5684
5685<h5>Syntax:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5686<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]5687 declare void @llvm.gcroot(i8** %ptrloc, i8* %metadata)
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5688</pre>
5689
5690<h5>Overview:</h5>
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]5691<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]5692 the code generator, and allows some metadata to be associated with it.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5693
5694<h5>Arguments:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5695<p>The first argument specifies the address of a stack object that contains the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5696 root pointer. The second pointer (which must be either a constant or a
5697 global value address) contains the meta-data to be associated with the
5698 root.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5699
5700<h5>Semantics:</h5>
Chris Lattner851b7712008-04-24 05:59:56 +0000[diff] [blame]5701<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]5702 location. At compile-time, the code generator generates information to allow
5703 the runtime to find the pointer at GC safe points. The '<tt>llvm.gcroot</tt>'
5704 intrinsic may only be used in a function which <a href="#gc">specifies a GC
5705 algorithm</a>.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5706
5707</div>
5708
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5709<!-- _______________________________________________________________________ -->
5710<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5711 <a name="int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5712</div>
5713
5714<div class="doc_text">
5715
5716<h5>Syntax:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5717<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]5718 declare i8* @llvm.gcread(i8* %ObjPtr, i8** %Ptr)
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5719</pre>
5720
5721<h5>Overview:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5722<p>The '<tt>llvm.gcread</tt>' intrinsic identifies reads of references from heap
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5723 locations, allowing garbage collector implementations that require read
5724 barriers.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5725
5726<h5>Arguments:</h5>
Chris Lattnerf9228072006-03-14 20:02:51 +0000[diff] [blame]5727<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]5728 allocated from the garbage collector. The first object is a pointer to the
5729 start of the referenced object, if needed by the language runtime (otherwise
5730 null).</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5731
5732<h5>Semantics:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5733<p>The '<tt>llvm.gcread</tt>' intrinsic has the same semantics as a load
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5734 instruction, but may be replaced with substantially more complex code by the
5735 garbage collector runtime, as needed. The '<tt>llvm.gcread</tt>' intrinsic
5736 may only be used in a function which <a href="#gc">specifies a GC
5737 algorithm</a>.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5738
5739</div>
5740
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5741<!-- _______________________________________________________________________ -->
5742<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5743 <a name="int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5744</div>
5745
5746<div class="doc_text">
5747
5748<h5>Syntax:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5749<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]5750 declare void @llvm.gcwrite(i8* %P1, i8* %Obj, i8** %P2)
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5751</pre>
5752
5753<h5>Overview:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5754<p>The '<tt>llvm.gcwrite</tt>' intrinsic identifies writes of references to heap
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5755 locations, allowing garbage collector implementations that require write
5756 barriers (such as generational or reference counting collectors).</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5757
5758<h5>Arguments:</h5>
Chris Lattnerf9228072006-03-14 20:02:51 +0000[diff] [blame]5759<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]5760 object to store it to, and the third is the address of the field of Obj to
5761 store to. If the runtime does not require a pointer to the object, Obj may
5762 be null.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5763
5764<h5>Semantics:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5765<p>The '<tt>llvm.gcwrite</tt>' intrinsic has the same semantics as a store
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5766 instruction, but may be replaced with substantially more complex code by the
5767 garbage collector runtime, as needed. The '<tt>llvm.gcwrite</tt>' intrinsic
5768 may only be used in a function which <a href="#gc">specifies a GC
5769 algorithm</a>.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5770
5771</div>
5772
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5773<!-- ======================================================================= -->
5774<div class="doc_subsection">
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5775 <a name="int_codegen">Code Generator Intrinsics</a>
5776</div>
5777
5778<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5779
5780<p>These intrinsics are provided by LLVM to expose special features that may
5781 only be implemented with code generator support.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5782
5783</div>
5784
5785<!-- _______________________________________________________________________ -->
5786<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5787 <a name="int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5788</div>
5789
5790<div class="doc_text">
5791
5792<h5>Syntax:</h5>
5793<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]5794 declare i8 *@llvm.returnaddress(i32 &lt;level&gt;)
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5795</pre>
5796
5797<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5798<p>The '<tt>llvm.returnaddress</tt>' intrinsic attempts to compute a
5799 target-specific value indicating the return address of the current function
5800 or one of its callers.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5801
5802<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5803<p>The argument to this intrinsic indicates which function to return the address
5804 for. Zero indicates the calling function, one indicates its caller, etc.
5805 The argument is <b>required</b> to be a constant integer value.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5806
5807<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5808<p>The '<tt>llvm.returnaddress</tt>' intrinsic either returns a pointer
5809 indicating the return address of the specified call frame, or zero if it
5810 cannot be identified. The value returned by this intrinsic is likely to be
5811 incorrect or 0 for arguments other than zero, so it should only be used for
5812 debugging purposes.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5813
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5814<p>Note that calling this intrinsic does not prevent function inlining or other
5815 aggressive transformations, so the value returned may not be that of the
5816 obvious source-language caller.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5817
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5818</div>
5819
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5820<!-- _______________________________________________________________________ -->
5821<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5822 <a name="int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5823</div>
5824
5825<div class="doc_text">
5826
5827<h5>Syntax:</h5>
5828<pre>
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]5829 declare i8* @llvm.frameaddress(i32 &lt;level&gt;)
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5830</pre>
5831
5832<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5833<p>The '<tt>llvm.frameaddress</tt>' intrinsic attempts to return the
5834 target-specific frame pointer value for the specified stack frame.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5835
5836<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5837<p>The argument to this intrinsic indicates which function to return the frame
5838 pointer for. Zero indicates the calling function, one indicates its caller,
5839 etc. The argument is <b>required</b> to be a constant integer value.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5840
5841<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5842<p>The '<tt>llvm.frameaddress</tt>' intrinsic either returns a pointer
5843 indicating the frame address of the specified call frame, or zero if it
5844 cannot be identified. The value returned by this intrinsic is likely to be
5845 incorrect or 0 for arguments other than zero, so it should only be used for
5846 debugging purposes.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5847
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5848<p>Note that calling this intrinsic does not prevent function inlining or other
5849 aggressive transformations, so the value returned may not be that of the
5850 obvious source-language caller.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5851
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5852</div>
5853
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]5854<!-- _______________________________________________________________________ -->
5855<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5856 <a name="int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]5857</div>
5858
5859<div class="doc_text">
5860
5861<h5>Syntax:</h5>
5862<pre>
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]5863 declare i8* @llvm.stacksave()
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]5864</pre>
5865
5866<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5867<p>The '<tt>llvm.stacksave</tt>' intrinsic is used to remember the current state
5868 of the function stack, for use
5869 with <a href="#int_stackrestore"> <tt>llvm.stackrestore</tt></a>. This is
5870 useful for implementing language features like scoped automatic variable
5871 sized arrays in C99.</p>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]5872
5873<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5874<p>This intrinsic returns a opaque pointer value that can be passed
5875 to <a href="#int_stackrestore"><tt>llvm.stackrestore</tt></a>. When
5876 an <tt>llvm.stackrestore</tt> intrinsic is executed with a value saved
5877 from <tt>llvm.stacksave</tt>, it effectively restores the state of the stack
5878 to the state it was in when the <tt>llvm.stacksave</tt> intrinsic executed.
5879 In practice, this pops any <a href="#i_alloca">alloca</a> blocks from the
5880 stack that were allocated after the <tt>llvm.stacksave</tt> was executed.</p>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]5881
5882</div>
5883
5884<!-- _______________________________________________________________________ -->
5885<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5886 <a name="int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]5887</div>
5888
5889<div class="doc_text">
5890
5891<h5>Syntax:</h5>
5892<pre>
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]5893 declare void @llvm.stackrestore(i8* %ptr)
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]5894</pre>
5895
5896<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5897<p>The '<tt>llvm.stackrestore</tt>' intrinsic is used to restore the state of
5898 the function stack to the state it was in when the
5899 corresponding <a href="#int_stacksave"><tt>llvm.stacksave</tt></a> intrinsic
5900 executed. This is useful for implementing language features like scoped
5901 automatic variable sized arrays in C99.</p>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]5902
5903<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5904<p>See the description
5905 for <a href="#int_stacksave"><tt>llvm.stacksave</tt></a>.</p>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]5906
5907</div>
5908
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]5909<!-- _______________________________________________________________________ -->
5910<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5911 <a name="int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a>
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]5912</div>
5913
5914<div class="doc_text">
5915
5916<h5>Syntax:</h5>
5917<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]5918 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]5919</pre>
5920
5921<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5922<p>The '<tt>llvm.prefetch</tt>' intrinsic is a hint to the code generator to
5923 insert a prefetch instruction if supported; otherwise, it is a noop.
5924 Prefetches have no effect on the behavior of the program but can change its
5925 performance characteristics.</p>
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]5926
5927<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5928<p><tt>address</tt> is the address to be prefetched, <tt>rw</tt> is the
5929 specifier determining if the fetch should be for a read (0) or write (1),
5930 and <tt>locality</tt> is a temporal locality specifier ranging from (0) - no
5931 locality, to (3) - extremely local keep in cache. The <tt>rw</tt>
5932 and <tt>locality</tt> arguments must be constant integers.</p>
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]5933
5934<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5935<p>This intrinsic does not modify the behavior of the program. In particular,
5936 prefetches cannot trap and do not produce a value. On targets that support
5937 this intrinsic, the prefetch can provide hints to the processor cache for
5938 better performance.</p>
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]5939
5940</div>
5941
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]5942<!-- _______________________________________________________________________ -->
5943<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5944 <a name="int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a>
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]5945</div>
5946
5947<div class="doc_text">
5948
5949<h5>Syntax:</h5>
5950<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]5951 declare void @llvm.pcmarker(i32 &lt;id&gt;)
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]5952</pre>
5953
5954<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5955<p>The '<tt>llvm.pcmarker</tt>' intrinsic is a method to export a Program
5956 Counter (PC) in a region of code to simulators and other tools. The method
5957 is target specific, but it is expected that the marker will use exported
5958 symbols to transmit the PC of the marker. The marker makes no guarantees
5959 that it will remain with any specific instruction after optimizations. It is
5960 possible that the presence of a marker will inhibit optimizations. The
5961 intended use is to be inserted after optimizations to allow correlations of
5962 simulation runs.</p>
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]5963
5964<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5965<p><tt>id</tt> is a numerical id identifying the marker.</p>
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]5966
5967<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5968<p>This intrinsic does not modify the behavior of the program. Backends that do
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]5969 not support this intrinsic may ignore it.</p>
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]5970
5971</div>
5972
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]5973<!-- _______________________________________________________________________ -->
5974<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5975 <a name="int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a>
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]5976</div>
5977
5978<div class="doc_text">
5979
5980<h5>Syntax:</h5>
5981<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]5982 declare i64 @llvm.readcyclecounter()
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]5983</pre>
5984
5985<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5986<p>The '<tt>llvm.readcyclecounter</tt>' intrinsic provides access to the cycle
5987 counter register (or similar low latency, high accuracy clocks) on those
5988 targets that support it. On X86, it should map to RDTSC. On Alpha, it
5989 should map to RPCC. As the backing counters overflow quickly (on the order
5990 of 9 seconds on alpha), this should only be used for small timings.</p>
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]5991
5992<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5993<p>When directly supported, reading the cycle counter should not modify any
5994 memory. Implementations are allowed to either return a application specific
5995 value or a system wide value. On backends without support, this is lowered
5996 to a constant 0.</p>
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]5997
5998</div>
5999
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6000<!-- ======================================================================= -->
6001<div class="doc_subsection">
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6002 <a name="int_libc">Standard C Library Intrinsics</a>
6003</div>
6004
6005<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6006
6007<p>LLVM provides intrinsics for a few important standard C library functions.
6008 These intrinsics allow source-language front-ends to pass information about
6009 the alignment of the pointer arguments to the code generator, providing
6010 opportunity for more efficient code generation.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6011
6012</div>
6013
6014<!-- _______________________________________________________________________ -->
6015<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6016 <a name="int_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6017</div>
6018
6019<div class="doc_text">
6020
6021<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6022<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]6023 integer bit width and for different address spaces. Not all targets support
6024 all bit widths however.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6025
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6026<pre>
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]6027 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]6028 i32 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]6029 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]6030 i64 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6031</pre>
6032
6033<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6034<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
6035 source location to the destination location.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6036
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6037<p>Note that, unlike the standard libc function, the <tt>llvm.memcpy.*</tt>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6038 intrinsics do not return a value, takes extra alignment/isvolatile arguments
6039 and the pointers can be in specified address spaces.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6040
6041<h5>Arguments:</h5>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6042
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6043<p>The first argument is a pointer to the destination, the second is a pointer
6044 to the source. The third argument is an integer argument specifying the
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6045 number of bytes to copy, the fourth argument is the alignment of the
6046 source and destination locations, and the fifth is a boolean indicating a
6047 volatile access.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6048
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]6049<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]6050 then the caller guarantees that both the source and destination pointers are
6051 aligned to that boundary.</p>
Chris Lattner4c67c482004-02-12 21:18:15 +0000[diff] [blame]6052
Jeffrey Yasskin5d284ae2010-04-26 21:21:24 +0000[diff] [blame]6053<p>If the <tt>isvolatile</tt> parameter is <tt>true</tt>, the
6054 <tt>llvm.memcpy</tt> call is a <a href="#volatile">volatile operation</a>.
6055 The detailed access behavior is not very cleanly specified and it is unwise
6056 to depend on it.</p>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6057
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6058<h5>Semantics:</h5>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6059
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6060<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
6061 source location to the destination location, which are not allowed to
6062 overlap. It copies "len" bytes of memory over. If the argument is known to
6063 be aligned to some boundary, this can be specified as the fourth argument,
6064 otherwise it should be set to 0 or 1.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6065
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6066</div>
6067
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6068<!-- _______________________________________________________________________ -->
6069<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6070 <a name="int_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a>
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6071</div>
6072
6073<div class="doc_text">
6074
6075<h5>Syntax:</h5>
Chris Lattnerdd708342008-11-21 16:42:48 +0000[diff] [blame]6076<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]6077 width and for different address space. Not all targets support all bit
6078 widths however.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6079
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6080<pre>
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]6081 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]6082 i32 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]6083 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]6084 i64 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6085</pre>
6086
6087<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6088<p>The '<tt>llvm.memmove.*</tt>' intrinsics move a block of memory from the
6089 source location to the destination location. It is similar to the
6090 '<tt>llvm.memcpy</tt>' intrinsic but allows the two memory locations to
6091 overlap.</p>
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6092
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6093<p>Note that, unlike the standard libc function, the <tt>llvm.memmove.*</tt>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6094 intrinsics do not return a value, takes extra alignment/isvolatile arguments
6095 and the pointers can be in specified address spaces.</p>
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6096
6097<h5>Arguments:</h5>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6098
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6099<p>The first argument is a pointer to the destination, the second is a pointer
6100 to the source. The third argument is an integer argument specifying the
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6101 number of bytes to copy, the fourth argument is the alignment of the
6102 source and destination locations, and the fifth is a boolean indicating a
6103 volatile access.</p>
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6104
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]6105<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]6106 then the caller guarantees that the source and destination pointers are
6107 aligned to that boundary.</p>
Chris Lattner4c67c482004-02-12 21:18:15 +0000[diff] [blame]6108
Jeffrey Yasskin5d284ae2010-04-26 21:21:24 +0000[diff] [blame]6109<p>If the <tt>isvolatile</tt> parameter is <tt>true</tt>, the
6110 <tt>llvm.memmove</tt> call is a <a href="#volatile">volatile operation</a>.
6111 The detailed access behavior is not very cleanly specified and it is unwise
6112 to depend on it.</p>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6113
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6114<h5>Semantics:</h5>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6115
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6116<p>The '<tt>llvm.memmove.*</tt>' intrinsics copy a block of memory from the
6117 source location to the destination location, which may overlap. It copies
6118 "len" bytes of memory over. If the argument is known to be aligned to some
6119 boundary, this can be specified as the fourth argument, otherwise it should
6120 be set to 0 or 1.</p>
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6121
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6122</div>
6123
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6124<!-- _______________________________________________________________________ -->
6125<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6126 <a name="int_memset">'<tt>llvm.memset.*</tt>' Intrinsics</a>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6127</div>
6128
6129<div class="doc_text">
6130
6131<h5>Syntax:</h5>
Chris Lattnerdd708342008-11-21 16:42:48 +0000[diff] [blame]6132<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]6133 width and for different address spaces. However, not all targets support all
6134 bit widths.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6135
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6136<pre>
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]6137 declare void @llvm.memset.p0i8.i32(i8* &lt;dest&gt;, i8 &lt;val&gt;,
Chris Lattner685db9d2010-04-08 00:54:34 +0000[diff] [blame]6138 i32 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]6139 declare void @llvm.memset.p0i8.i64(i8* &lt;dest&gt;, i8 &lt;val&gt;,
Chris Lattner685db9d2010-04-08 00:54:34 +0000[diff] [blame]6140 i64 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6141</pre>
6142
6143<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6144<p>The '<tt>llvm.memset.*</tt>' intrinsics fill a block of memory with a
6145 particular byte value.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6146
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6147<p>Note that, unlike the standard libc function, the <tt>llvm.memset</tt>
John Criswellad05ae42010-07-30 16:30:28 +0000[diff] [blame]6148 intrinsic does not return a value and takes extra alignment/volatile
6149 arguments. Also, the destination can be in an arbitrary address space.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6150
6151<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6152<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]6153 byte value with which to fill it, the third argument is an integer argument
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6154 specifying the number of bytes to fill, and the fourth argument is the known
John Criswellad05ae42010-07-30 16:30:28 +0000[diff] [blame]6155 alignment of the destination location.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6156
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]6157<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]6158 then the caller guarantees that the destination pointer is aligned to that
6159 boundary.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6160
Jeffrey Yasskin5d284ae2010-04-26 21:21:24 +0000[diff] [blame]6161<p>If the <tt>isvolatile</tt> parameter is <tt>true</tt>, the
6162 <tt>llvm.memset</tt> call is a <a href="#volatile">volatile operation</a>.
6163 The detailed access behavior is not very cleanly specified and it is unwise
6164 to depend on it.</p>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6165
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6166<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6167<p>The '<tt>llvm.memset.*</tt>' intrinsics fill "len" bytes of memory starting
6168 at the destination location. If the argument is known to be aligned to some
6169 boundary, this can be specified as the fourth argument, otherwise it should
6170 be set to 0 or 1.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6171
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6172</div>
6173
Chris Lattner3b4f4372004-06-11 02:28:03 +0000[diff] [blame]6174<!-- _______________________________________________________________________ -->
6175<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6176 <a name="int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a>
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]6177</div>
6178
6179<div class="doc_text">
6180
6181<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6182<p>This is an overloaded intrinsic. You can use <tt>llvm.sqrt</tt> on any
6183 floating point or vector of floating point type. Not all targets support all
6184 types however.</p>
6185
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]6186<pre>
Dale Johannesendd89d272007-10-02 17:47:38 +0000[diff] [blame]6187 declare float @llvm.sqrt.f32(float %Val)
6188 declare double @llvm.sqrt.f64(double %Val)
6189 declare x86_fp80 @llvm.sqrt.f80(x86_fp80 %Val)
6190 declare fp128 @llvm.sqrt.f128(fp128 %Val)
6191 declare ppc_fp128 @llvm.sqrt.ppcf128(ppc_fp128 %Val)
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]6192</pre>
6193
6194<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6195<p>The '<tt>llvm.sqrt</tt>' intrinsics return the sqrt of the specified operand,
6196 returning the same value as the libm '<tt>sqrt</tt>' functions would.
6197 Unlike <tt>sqrt</tt> in libm, however, <tt>llvm.sqrt</tt> has undefined
6198 behavior for negative numbers other than -0.0 (which allows for better
6199 optimization, because there is no need to worry about errno being
6200 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]6201
6202<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6203<p>The argument and return value are floating point numbers of the same
6204 type.</p>
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]6205
6206<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6207<p>This function returns the sqrt of the specified operand if it is a
6208 nonnegative floating point number.</p>
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]6209
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]6210</div>
6211
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]6212<!-- _______________________________________________________________________ -->
6213<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6214 <a name="int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a>
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]6215</div>
6216
6217<div class="doc_text">
6218
6219<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6220<p>This is an overloaded intrinsic. You can use <tt>llvm.powi</tt> on any
6221 floating point or vector of floating point type. Not all targets support all
6222 types however.</p>
6223
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]6224<pre>
Dale Johannesendd89d272007-10-02 17:47:38 +0000[diff] [blame]6225 declare float @llvm.powi.f32(float %Val, i32 %power)
6226 declare double @llvm.powi.f64(double %Val, i32 %power)
6227 declare x86_fp80 @llvm.powi.f80(x86_fp80 %Val, i32 %power)
6228 declare fp128 @llvm.powi.f128(fp128 %Val, i32 %power)
6229 declare ppc_fp128 @llvm.powi.ppcf128(ppc_fp128 %Val, i32 %power)
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]6230</pre>
6231
6232<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6233<p>The '<tt>llvm.powi.*</tt>' intrinsics return the first operand raised to the
6234 specified (positive or negative) power. The order of evaluation of
6235 multiplications is not defined. When a vector of floating point type is
6236 used, the second argument remains a scalar integer value.</p>
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]6237
6238<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6239<p>The second argument is an integer power, and the first is a value to raise to
6240 that power.</p>
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]6241
6242<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6243<p>This function returns the first value raised to the second power with an
6244 unspecified sequence of rounding operations.</p>
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]6245
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]6246</div>
6247
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6248<!-- _______________________________________________________________________ -->
6249<div class="doc_subsubsection">
6250 <a name="int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a>
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.sin</tt> on any
6257 floating point or vector of floating point type. Not all targets support all
6258 types however.</p>
6259
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6260<pre>
6261 declare float @llvm.sin.f32(float %Val)
6262 declare double @llvm.sin.f64(double %Val)
6263 declare x86_fp80 @llvm.sin.f80(x86_fp80 %Val)
6264 declare fp128 @llvm.sin.f128(fp128 %Val)
6265 declare ppc_fp128 @llvm.sin.ppcf128(ppc_fp128 %Val)
6266</pre>
6267
6268<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6269<p>The '<tt>llvm.sin.*</tt>' intrinsics return the sine of the operand.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6270
6271<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6272<p>The argument and return value are floating point numbers of the same
6273 type.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6274
6275<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6276<p>This function returns the sine of the specified operand, returning the same
6277 values as the libm <tt>sin</tt> functions would, and handles error conditions
6278 in the same way.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6279
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6280</div>
6281
6282<!-- _______________________________________________________________________ -->
6283<div class="doc_subsubsection">
6284 <a name="int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a>
6285</div>
6286
6287<div class="doc_text">
6288
6289<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6290<p>This is an overloaded intrinsic. You can use <tt>llvm.cos</tt> on any
6291 floating point or vector of floating point type. Not all targets support all
6292 types however.</p>
6293
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6294<pre>
6295 declare float @llvm.cos.f32(float %Val)
6296 declare double @llvm.cos.f64(double %Val)
6297 declare x86_fp80 @llvm.cos.f80(x86_fp80 %Val)
6298 declare fp128 @llvm.cos.f128(fp128 %Val)
6299 declare ppc_fp128 @llvm.cos.ppcf128(ppc_fp128 %Val)
6300</pre>
6301
6302<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6303<p>The '<tt>llvm.cos.*</tt>' intrinsics return the cosine of the operand.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6304
6305<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6306<p>The argument and return value are floating point numbers of the same
6307 type.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6308
6309<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6310<p>This function returns the cosine of the specified operand, returning the same
6311 values as the libm <tt>cos</tt> functions would, and handles error conditions
6312 in the same way.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6313
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6314</div>
6315
6316<!-- _______________________________________________________________________ -->
6317<div class="doc_subsubsection">
6318 <a name="int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a>
6319</div>
6320
6321<div class="doc_text">
6322
6323<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6324<p>This is an overloaded intrinsic. You can use <tt>llvm.pow</tt> on any
6325 floating point or vector of floating point type. Not all targets support all
6326 types however.</p>
6327
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6328<pre>
6329 declare float @llvm.pow.f32(float %Val, float %Power)
6330 declare double @llvm.pow.f64(double %Val, double %Power)
6331 declare x86_fp80 @llvm.pow.f80(x86_fp80 %Val, x86_fp80 %Power)
6332 declare fp128 @llvm.pow.f128(fp128 %Val, fp128 %Power)
6333 declare ppc_fp128 @llvm.pow.ppcf128(ppc_fp128 %Val, ppc_fp128 Power)
6334</pre>
6335
6336<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6337<p>The '<tt>llvm.pow.*</tt>' intrinsics return the first operand raised to the
6338 specified (positive or negative) power.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6339
6340<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6341<p>The second argument is a floating point power, and the first is a value to
6342 raise to that power.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6343
6344<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6345<p>This function returns the first value raised to the second power, returning
6346 the same values as the libm <tt>pow</tt> functions would, and handles error
6347 conditions in the same way.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6348
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6349</div>
6350
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6351<!-- ======================================================================= -->
6352<div class="doc_subsection">
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]6353 <a name="int_manip">Bit Manipulation Intrinsics</a>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6354</div>
6355
6356<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6357
6358<p>LLVM provides intrinsics for a few important bit manipulation operations.
6359 These allow efficient code generation for some algorithms.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6360
6361</div>
6362
6363<!-- _______________________________________________________________________ -->
6364<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6365 <a name="int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a>
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]6366</div>
6367
6368<div class="doc_text">
6369
6370<h5>Syntax:</h5>
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]6371<p>This is an overloaded intrinsic function. You can use bswap on any integer
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6372 type that is an even number of bytes (i.e. BitWidth % 16 == 0).</p>
6373
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]6374<pre>
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]6375 declare i16 @llvm.bswap.i16(i16 &lt;id&gt;)
6376 declare i32 @llvm.bswap.i32(i32 &lt;id&gt;)
6377 declare i64 @llvm.bswap.i64(i64 &lt;id&gt;)
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]6378</pre>
6379
6380<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6381<p>The '<tt>llvm.bswap</tt>' family of intrinsics is used to byte swap integer
6382 values with an even number of bytes (positive multiple of 16 bits). These
6383 are useful for performing operations on data that is not in the target's
6384 native byte order.</p>
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]6385
6386<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6387<p>The <tt>llvm.bswap.i16</tt> intrinsic returns an i16 value that has the high
6388 and low byte of the input i16 swapped. Similarly,
6389 the <tt>llvm.bswap.i32</tt> intrinsic returns an i32 value that has the four
6390 bytes of the input i32 swapped, so that if the input bytes are numbered 0, 1,
6391 2, 3 then the returned i32 will have its bytes in 3, 2, 1, 0 order.
6392 The <tt>llvm.bswap.i48</tt>, <tt>llvm.bswap.i64</tt> and other intrinsics
6393 extend this concept to additional even-byte lengths (6 bytes, 8 bytes and
6394 more, respectively).</p>
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]6395
6396</div>
6397
6398<!-- _______________________________________________________________________ -->
6399<div class="doc_subsubsection">
Reid Spencerb4f9a6f2006-01-16 21:12:35 +0000[diff] [blame]6400 <a name="int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic</a>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6401</div>
6402
6403<div class="doc_text">
6404
6405<h5>Syntax:</h5>
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]6406<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]6407 width. Not all targets support all bit widths however.</p>
6408
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6409<pre>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6410 declare i8 @llvm.ctpop.i8(i8 &lt;src&gt;)
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]6411 declare i16 @llvm.ctpop.i16(i16 &lt;src&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]6412 declare i32 @llvm.ctpop.i32(i32 &lt;src&gt;)
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]6413 declare i64 @llvm.ctpop.i64(i64 &lt;src&gt;)
6414 declare i256 @llvm.ctpop.i256(i256 &lt;src&gt;)
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6415</pre>
6416
6417<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6418<p>The '<tt>llvm.ctpop</tt>' family of intrinsics counts the number of bits set
6419 in a value.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6420
6421<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6422<p>The only argument is the value to be counted. The argument may be of any
6423 integer type. The return type must match the argument type.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6424
6425<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6426<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]6427
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6428</div>
6429
6430<!-- _______________________________________________________________________ -->
6431<div class="doc_subsubsection">
Chris Lattnerb748c672006-01-16 22:34:14 +0000[diff] [blame]6432 <a name="int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic</a>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6433</div>
6434
6435<div class="doc_text">
6436
6437<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6438<p>This is an overloaded intrinsic. You can use <tt>llvm.ctlz</tt> on any
6439 integer bit width. Not all targets support all bit widths however.</p>
6440
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6441<pre>
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]6442 declare i8 @llvm.ctlz.i8 (i8 &lt;src&gt;)
6443 declare i16 @llvm.ctlz.i16(i16 &lt;src&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]6444 declare i32 @llvm.ctlz.i32(i32 &lt;src&gt;)
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]6445 declare i64 @llvm.ctlz.i64(i64 &lt;src&gt;)
6446 declare i256 @llvm.ctlz.i256(i256 &lt;src&gt;)
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6447</pre>
6448
6449<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6450<p>The '<tt>llvm.ctlz</tt>' family of intrinsic functions counts the number of
6451 leading zeros in a variable.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6452
6453<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6454<p>The only argument is the value to be counted. The argument may be of any
6455 integer type. The return type must match the argument type.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6456
6457<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6458<p>The '<tt>llvm.ctlz</tt>' intrinsic counts the leading (most significant)
6459 zeros in a variable. If the src == 0 then the result is the size in bits of
6460 the type of src. For example, <tt>llvm.ctlz(i32 2) = 30</tt>.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6461
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6462</div>
Chris Lattner3b4f4372004-06-11 02:28:03 +0000[diff] [blame]6463
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]6464<!-- _______________________________________________________________________ -->
6465<div class="doc_subsubsection">
Chris Lattnerb748c672006-01-16 22:34:14 +0000[diff] [blame]6466 <a name="int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic</a>
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]6467</div>
6468
6469<div class="doc_text">
6470
6471<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6472<p>This is an overloaded intrinsic. You can use <tt>llvm.cttz</tt> on any
6473 integer bit width. Not all targets support all bit widths however.</p>
6474
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]6475<pre>
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]6476 declare i8 @llvm.cttz.i8 (i8 &lt;src&gt;)
6477 declare i16 @llvm.cttz.i16(i16 &lt;src&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]6478 declare i32 @llvm.cttz.i32(i32 &lt;src&gt;)
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]6479 declare i64 @llvm.cttz.i64(i64 &lt;src&gt;)
6480 declare i256 @llvm.cttz.i256(i256 &lt;src&gt;)
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]6481</pre>
6482
6483<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6484<p>The '<tt>llvm.cttz</tt>' family of intrinsic functions counts the number of
6485 trailing zeros.</p>
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]6486
6487<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6488<p>The only argument is the value to be counted. The argument may be of any
6489 integer type. The return type must match the argument type.</p>
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]6490
6491<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6492<p>The '<tt>llvm.cttz</tt>' intrinsic counts the trailing (least significant)
6493 zeros in a variable. If the src == 0 then the result is the size in bits of
6494 the type of src. For example, <tt>llvm.cttz(2) = 1</tt>.</p>
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]6495
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]6496</div>
6497
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]6498<!-- ======================================================================= -->
6499<div class="doc_subsection">
6500 <a name="int_overflow">Arithmetic with Overflow Intrinsics</a>
6501</div>
6502
6503<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6504
6505<p>LLVM provides intrinsics for some arithmetic with overflow operations.</p>
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]6506
6507</div>
6508
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6509<!-- _______________________________________________________________________ -->
6510<div class="doc_subsubsection">
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]6511 <a name="int_sadd_overflow">'<tt>llvm.sadd.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6512</div>
6513
6514<div class="doc_text">
6515
6516<h5>Syntax:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6517<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]6518 on any integer bit width.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6519
6520<pre>
6521 declare {i16, i1} @llvm.sadd.with.overflow.i16(i16 %a, i16 %b)
6522 declare {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
6523 declare {i64, i1} @llvm.sadd.with.overflow.i64(i64 %a, i64 %b)
6524</pre>
6525
6526<h5>Overview:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6527<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6528 a signed addition of the two arguments, and indicate whether an overflow
6529 occurred during the signed summation.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6530
6531<h5>Arguments:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6532<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]6533 be of integer types of any bit width, but they must have the same bit
6534 width. The second element of the result structure must be of
6535 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6536 undergo signed addition.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6537
6538<h5>Semantics:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6539<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6540 a signed addition of the two variables. They return a structure &mdash; the
6541 first element of which is the signed summation, and the second element of
6542 which is a bit specifying if the signed summation resulted in an
6543 overflow.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6544
6545<h5>Examples:</h5>
6546<pre>
6547 %res = call {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
6548 %sum = extractvalue {i32, i1} %res, 0
6549 %obit = extractvalue {i32, i1} %res, 1
6550 br i1 %obit, label %overflow, label %normal
6551</pre>
6552
6553</div>
6554
6555<!-- _______________________________________________________________________ -->
6556<div class="doc_subsubsection">
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]6557 <a name="int_uadd_overflow">'<tt>llvm.uadd.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6558</div>
6559
6560<div class="doc_text">
6561
6562<h5>Syntax:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6563<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]6564 on any integer bit width.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6565
6566<pre>
6567 declare {i16, i1} @llvm.uadd.with.overflow.i16(i16 %a, i16 %b)
6568 declare {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
6569 declare {i64, i1} @llvm.uadd.with.overflow.i64(i64 %a, i64 %b)
6570</pre>
6571
6572<h5>Overview:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6573<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6574 an unsigned addition of the two arguments, and indicate whether a carry
6575 occurred during the unsigned summation.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6576
6577<h5>Arguments:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6578<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]6579 be of integer types of any bit width, but they must have the same bit
6580 width. The second element of the result structure must be of
6581 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6582 undergo unsigned addition.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6583
6584<h5>Semantics:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6585<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6586 an unsigned addition of the two arguments. They return a structure &mdash;
6587 the first element of which is the sum, and the second element of which is a
6588 bit specifying if the unsigned summation resulted in a carry.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6589
6590<h5>Examples:</h5>
6591<pre>
6592 %res = call {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
6593 %sum = extractvalue {i32, i1} %res, 0
6594 %obit = extractvalue {i32, i1} %res, 1
6595 br i1 %obit, label %carry, label %normal
6596</pre>
6597
6598</div>
6599
6600<!-- _______________________________________________________________________ -->
6601<div class="doc_subsubsection">
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]6602 <a name="int_ssub_overflow">'<tt>llvm.ssub.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6603</div>
6604
6605<div class="doc_text">
6606
6607<h5>Syntax:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6608<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]6609 on any integer bit width.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6610
6611<pre>
6612 declare {i16, i1} @llvm.ssub.with.overflow.i16(i16 %a, i16 %b)
6613 declare {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
6614 declare {i64, i1} @llvm.ssub.with.overflow.i64(i64 %a, i64 %b)
6615</pre>
6616
6617<h5>Overview:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6618<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6619 a signed subtraction of the two arguments, and indicate whether an overflow
6620 occurred during the signed subtraction.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6621
6622<h5>Arguments:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6623<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]6624 be of integer types of any bit width, but they must have the same bit
6625 width. The second element of the result structure must be of
6626 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6627 undergo signed subtraction.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6628
6629<h5>Semantics:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6630<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6631 a signed subtraction of the two arguments. They return a structure &mdash;
6632 the first element of which is the subtraction, and the second element of
6633 which is a bit specifying if the signed subtraction resulted in an
6634 overflow.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6635
6636<h5>Examples:</h5>
6637<pre>
6638 %res = call {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
6639 %sum = extractvalue {i32, i1} %res, 0
6640 %obit = extractvalue {i32, i1} %res, 1
6641 br i1 %obit, label %overflow, label %normal
6642</pre>
6643
6644</div>
6645
6646<!-- _______________________________________________________________________ -->
6647<div class="doc_subsubsection">
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]6648 <a name="int_usub_overflow">'<tt>llvm.usub.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6649</div>
6650
6651<div class="doc_text">
6652
6653<h5>Syntax:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6654<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]6655 on any integer bit width.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6656
6657<pre>
6658 declare {i16, i1} @llvm.usub.with.overflow.i16(i16 %a, i16 %b)
6659 declare {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
6660 declare {i64, i1} @llvm.usub.with.overflow.i64(i64 %a, i64 %b)
6661</pre>
6662
6663<h5>Overview:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6664<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6665 an unsigned subtraction of the two arguments, and indicate whether an
6666 overflow occurred during the unsigned subtraction.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6667
6668<h5>Arguments:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6669<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]6670 be of integer types of any bit width, but they must have the same bit
6671 width. The second element of the result structure must be of
6672 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6673 undergo unsigned subtraction.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6674
6675<h5>Semantics:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6676<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6677 an unsigned subtraction of the two arguments. They return a structure &mdash;
6678 the first element of which is the subtraction, and the second element of
6679 which is a bit specifying if the unsigned subtraction resulted in an
6680 overflow.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6681
6682<h5>Examples:</h5>
6683<pre>
6684 %res = call {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
6685 %sum = extractvalue {i32, i1} %res, 0
6686 %obit = extractvalue {i32, i1} %res, 1
6687 br i1 %obit, label %overflow, label %normal
6688</pre>
6689
6690</div>
6691
6692<!-- _______________________________________________________________________ -->
6693<div class="doc_subsubsection">
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]6694 <a name="int_smul_overflow">'<tt>llvm.smul.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6695</div>
6696
6697<div class="doc_text">
6698
6699<h5>Syntax:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6700<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]6701 on any integer bit width.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6702
6703<pre>
6704 declare {i16, i1} @llvm.smul.with.overflow.i16(i16 %a, i16 %b)
6705 declare {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
6706 declare {i64, i1} @llvm.smul.with.overflow.i64(i64 %a, i64 %b)
6707</pre>
6708
6709<h5>Overview:</h5>
6710
6711<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6712 a signed multiplication of the two arguments, and indicate whether an
6713 overflow occurred during the signed multiplication.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6714
6715<h5>Arguments:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6716<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]6717 be of integer types of any bit width, but they must have the same bit
6718 width. The second element of the result structure must be of
6719 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6720 undergo signed multiplication.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6721
6722<h5>Semantics:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6723<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6724 a signed multiplication of the two arguments. They return a structure &mdash;
6725 the first element of which is the multiplication, and the second element of
6726 which is a bit specifying if the signed multiplication resulted in an
6727 overflow.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6728
6729<h5>Examples:</h5>
6730<pre>
6731 %res = call {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
6732 %sum = extractvalue {i32, i1} %res, 0
6733 %obit = extractvalue {i32, i1} %res, 1
6734 br i1 %obit, label %overflow, label %normal
6735</pre>
6736
Reid Spencer5bf54c82007-04-11 23:23:49 +0000[diff] [blame]6737</div>
6738
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]6739<!-- _______________________________________________________________________ -->
6740<div class="doc_subsubsection">
6741 <a name="int_umul_overflow">'<tt>llvm.umul.with.overflow.*</tt>' Intrinsics</a>
6742</div>
6743
6744<div class="doc_text">
6745
6746<h5>Syntax:</h5>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]6747<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]6748 on any integer bit width.</p>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]6749
6750<pre>
6751 declare {i16, i1} @llvm.umul.with.overflow.i16(i16 %a, i16 %b)
6752 declare {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
6753 declare {i64, i1} @llvm.umul.with.overflow.i64(i64 %a, i64 %b)
6754</pre>
6755
6756<h5>Overview:</h5>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]6757<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6758 a unsigned multiplication of the two arguments, and indicate whether an
6759 overflow occurred during the unsigned multiplication.</p>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]6760
6761<h5>Arguments:</h5>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]6762<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]6763 be of integer types of any bit width, but they must have the same bit
6764 width. The second element of the result structure must be of
6765 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6766 undergo unsigned multiplication.</p>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]6767
6768<h5>Semantics:</h5>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]6769<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6770 an unsigned multiplication of the two arguments. They return a structure
6771 &mdash; the first element of which is the multiplication, and the second
6772 element of which is a bit specifying if the unsigned multiplication resulted
6773 in an overflow.</p>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]6774
6775<h5>Examples:</h5>
6776<pre>
6777 %res = call {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
6778 %sum = extractvalue {i32, i1} %res, 0
6779 %obit = extractvalue {i32, i1} %res, 1
6780 br i1 %obit, label %overflow, label %normal
6781</pre>
6782
6783</div>
6784
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]6785<!-- ======================================================================= -->
6786<div class="doc_subsection">
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]6787 <a name="int_fp16">Half Precision Floating Point Intrinsics</a>
6788</div>
6789
6790<div class="doc_text">
6791
Chris Lattner022a9fb2010-03-15 04:12:21 +0000[diff] [blame]6792<p>Half precision floating point is a storage-only format. This means that it is
6793 a dense encoding (in memory) but does not support computation in the
6794 format.</p>
Chris Lattnerbbd8bd32010-03-14 23:03:31 +0000[diff] [blame]6795
Chris Lattner022a9fb2010-03-15 04:12:21 +0000[diff] [blame]6796<p>This means that code must first load the half-precision floating point
Chris Lattnerbbd8bd32010-03-14 23:03:31 +0000[diff] [blame]6797 value as an i16, then convert it to float with <a
6798 href="#int_convert_from_fp16"><tt>llvm.convert.from.fp16</tt></a>.
6799 Computation can then be performed on the float value (including extending to
Chris Lattner022a9fb2010-03-15 04:12:21 +0000[diff] [blame]6800 double etc). To store the value back to memory, it is first converted to
6801 float if needed, then converted to i16 with
Chris Lattnerbbd8bd32010-03-14 23:03:31 +0000[diff] [blame]6802 <a href="#int_convert_to_fp16"><tt>llvm.convert.to.fp16</tt></a>, then
6803 storing as an i16 value.</p>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]6804</div>
6805
6806<!-- _______________________________________________________________________ -->
6807<div class="doc_subsubsection">
Chris Lattnerbbd8bd32010-03-14 23:03:31 +0000[diff] [blame]6808 <a name="int_convert_to_fp16">'<tt>llvm.convert.to.fp16</tt>' Intrinsic</a>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]6809</div>
6810
6811<div class="doc_text">
6812
6813<h5>Syntax:</h5>
6814<pre>
6815 declare i16 @llvm.convert.to.fp16(f32 %a)
6816</pre>
6817
6818<h5>Overview:</h5>
6819<p>The '<tt>llvm.convert.to.fp16</tt>' intrinsic function performs
6820 a conversion from single precision floating point format to half precision
6821 floating point format.</p>
6822
6823<h5>Arguments:</h5>
6824<p>The intrinsic function contains single argument - the value to be
6825 converted.</p>
6826
6827<h5>Semantics:</h5>
6828<p>The '<tt>llvm.convert.to.fp16</tt>' intrinsic function performs
6829 a conversion from single precision floating point format to half precision
Chris Lattner022a9fb2010-03-15 04:12:21 +0000[diff] [blame]6830 floating point format. The return value is an <tt>i16</tt> which
Chris Lattnerbbd8bd32010-03-14 23:03:31 +0000[diff] [blame]6831 contains the converted number.</p>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]6832
6833<h5>Examples:</h5>
6834<pre>
6835 %res = call i16 @llvm.convert.to.fp16(f32 %a)
6836 store i16 %res, i16* @x, align 2
6837</pre>
6838
6839</div>
6840
6841<!-- _______________________________________________________________________ -->
6842<div class="doc_subsubsection">
Chris Lattnerbbd8bd32010-03-14 23:03:31 +0000[diff] [blame]6843 <a name="int_convert_from_fp16">'<tt>llvm.convert.from.fp16</tt>' Intrinsic</a>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]6844</div>
6845
6846<div class="doc_text">
6847
6848<h5>Syntax:</h5>
6849<pre>
6850 declare f32 @llvm.convert.from.fp16(i16 %a)
6851</pre>
6852
6853<h5>Overview:</h5>
6854<p>The '<tt>llvm.convert.from.fp16</tt>' intrinsic function performs
6855 a conversion from half precision floating point format to single precision
6856 floating point format.</p>
6857
6858<h5>Arguments:</h5>
6859<p>The intrinsic function contains single argument - the value to be
6860 converted.</p>
6861
6862<h5>Semantics:</h5>
6863<p>The '<tt>llvm.convert.from.fp16</tt>' intrinsic function performs a
Chris Lattner022a9fb2010-03-15 04:12:21 +0000[diff] [blame]6864 conversion from half single precision floating point format to single
Chris Lattnerbbd8bd32010-03-14 23:03:31 +0000[diff] [blame]6865 precision floating point format. The input half-float value is represented by
6866 an <tt>i16</tt> value.</p>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]6867
6868<h5>Examples:</h5>
6869<pre>
6870 %a = load i16* @x, align 2
6871 %res = call f32 @llvm.convert.from.fp16(i16 %a)
6872</pre>
6873
6874</div>
6875
6876<!-- ======================================================================= -->
6877<div class="doc_subsection">
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]6878 <a name="int_debugger">Debugger Intrinsics</a>
6879</div>
6880
6881<div class="doc_text">
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]6882
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6883<p>The LLVM debugger intrinsics (which all start with <tt>llvm.dbg.</tt>
6884 prefix), are described in
6885 the <a href="SourceLevelDebugging.html#format_common_intrinsics">LLVM Source
6886 Level Debugging</a> document.</p>
6887
6888</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]6889
Jim Laskey2211f492007-03-14 19:31:19 +0000[diff] [blame]6890<!-- ======================================================================= -->
6891<div class="doc_subsection">
6892 <a name="int_eh">Exception Handling Intrinsics</a>
6893</div>
6894
6895<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6896
6897<p>The LLVM exception handling intrinsics (which all start with
6898 <tt>llvm.eh.</tt> prefix), are described in
6899 the <a href="ExceptionHandling.html#format_common_intrinsics">LLVM Exception
6900 Handling</a> document.</p>
6901
Jim Laskey2211f492007-03-14 19:31:19 +0000[diff] [blame]6902</div>
6903
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]6904<!-- ======================================================================= -->
6905<div class="doc_subsection">
Duncan Sands86e01192007-09-11 14:10:23 +0000[diff] [blame]6906 <a name="int_trampoline">Trampoline Intrinsic</a>
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]6907</div>
6908
6909<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6910
6911<p>This intrinsic makes it possible to excise one parameter, marked with
Dan Gohman3770af52010-07-02 23:18:08 +0000[diff] [blame]6912 the <a href="#nest"><tt>nest</tt></a> attribute, from a function.
6913 The result is a callable
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6914 function pointer lacking the nest parameter - the caller does not need to
6915 provide a value for it. Instead, the value to use is stored in advance in a
6916 "trampoline", a block of memory usually allocated on the stack, which also
6917 contains code to splice the nest value into the argument list. This is used
6918 to implement the GCC nested function address extension.</p>
6919
6920<p>For example, if the function is
6921 <tt>i32 f(i8* nest %c, i32 %x, i32 %y)</tt> then the resulting function
6922 pointer has signature <tt>i32 (i32, i32)*</tt>. It can be created as
6923 follows:</p>
6924
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]6925<pre class="doc_code">
Duncan Sands86e01192007-09-11 14:10:23 +0000[diff] [blame]6926 %tramp = alloca [10 x i8], align 4 ; size and alignment only correct for X86
6927 %tramp1 = getelementptr [10 x i8]* %tramp, i32 0, i32 0
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]6928 %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]6929 %fp = bitcast i8* %p to i32 (i32, i32)*
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]6930</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6931
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]6932<p>The call <tt>%val = call i32 %fp(i32 %x, i32 %y)</tt> is then equivalent
6933 to <tt>%val = call i32 %f(i8* %nval, i32 %x, i32 %y)</tt>.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6934
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]6935</div>
6936
6937<!-- _______________________________________________________________________ -->
6938<div class="doc_subsubsection">
6939 <a name="int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a>
6940</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6941
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]6942<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6943
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]6944<h5>Syntax:</h5>
6945<pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6946 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]6947</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6948
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]6949<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6950<p>This fills the memory pointed to by <tt>tramp</tt> with code and returns a
6951 function pointer suitable for executing it.</p>
6952
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]6953<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6954<p>The <tt>llvm.init.trampoline</tt> intrinsic takes three arguments, all
6955 pointers. The <tt>tramp</tt> argument must point to a sufficiently large and
6956 sufficiently aligned block of memory; this memory is written to by the
6957 intrinsic. Note that the size and the alignment are target-specific - LLVM
6958 currently provides no portable way of determining them, so a front-end that
6959 generates this intrinsic needs to have some target-specific knowledge.
6960 The <tt>func</tt> argument must hold a function bitcast to
6961 an <tt>i8*</tt>.</p>
6962
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]6963<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6964<p>The block of memory pointed to by <tt>tramp</tt> is filled with target
6965 dependent code, turning it into a function. A pointer to this function is
6966 returned, but needs to be bitcast to an <a href="#int_trampoline">appropriate
6967 function pointer type</a> before being called. The new function's signature
6968 is the same as that of <tt>func</tt> with any arguments marked with
6969 the <tt>nest</tt> attribute removed. At most one such <tt>nest</tt> argument
6970 is allowed, and it must be of pointer type. Calling the new function is
6971 equivalent to calling <tt>func</tt> with the same argument list, but
6972 with <tt>nval</tt> used for the missing <tt>nest</tt> argument. If, after
6973 calling <tt>llvm.init.trampoline</tt>, the memory pointed to
6974 by <tt>tramp</tt> is modified, then the effect of any later call to the
6975 returned function pointer is undefined.</p>
6976
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]6977</div>
6978
6979<!-- ======================================================================= -->
6980<div class="doc_subsection">
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]6981 <a name="int_atomics">Atomic Operations and Synchronization Intrinsics</a>
6982</div>
6983
6984<div class="doc_text">
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]6985
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6986<p>These intrinsic functions expand the "universal IR" of LLVM to represent
6987 hardware constructs for atomic operations and memory synchronization. This
6988 provides an interface to the hardware, not an interface to the programmer. It
6989 is aimed at a low enough level to allow any programming models or APIs
6990 (Application Programming Interfaces) which need atomic behaviors to map
6991 cleanly onto it. It is also modeled primarily on hardware behavior. Just as
6992 hardware provides a "universal IR" for source languages, it also provides a
6993 starting point for developing a "universal" atomic operation and
6994 synchronization IR.</p>
6995
6996<p>These do <em>not</em> form an API such as high-level threading libraries,
6997 software transaction memory systems, atomic primitives, and intrinsic
6998 functions as found in BSD, GNU libc, atomic_ops, APR, and other system and
6999 application libraries. The hardware interface provided by LLVM should allow
7000 a clean implementation of all of these APIs and parallel programming models.
7001 No one model or paradigm should be selected above others unless the hardware
7002 itself ubiquitously does so.</p>
7003
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7004</div>
7005
7006<!-- _______________________________________________________________________ -->
7007<div class="doc_subsubsection">
7008 <a name="int_memory_barrier">'<tt>llvm.memory.barrier</tt>' Intrinsic</a>
7009</div>
7010<div class="doc_text">
7011<h5>Syntax:</h5>
7012<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7013 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]7014</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7015
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7016<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7017<p>The <tt>llvm.memory.barrier</tt> intrinsic guarantees ordering between
7018 specific pairs of memory access types.</p>
7019
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7020<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7021<p>The <tt>llvm.memory.barrier</tt> intrinsic requires five boolean arguments.
7022 The first four arguments enables a specific barrier as listed below. The
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]7023 fifth argument specifies that the barrier applies to io or device or uncached
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7024 memory.</p>
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7025
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7026<ul>
7027 <li><tt>ll</tt>: load-load barrier</li>
7028 <li><tt>ls</tt>: load-store barrier</li>
7029 <li><tt>sl</tt>: store-load barrier</li>
7030 <li><tt>ss</tt>: store-store barrier</li>
7031 <li><tt>device</tt>: barrier applies to device and uncached memory also.</li>
7032</ul>
7033
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7034<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7035<p>This intrinsic causes the system to enforce some ordering constraints upon
7036 the loads and stores of the program. This barrier does not
7037 indicate <em>when</em> any events will occur, it only enforces
7038 an <em>order</em> in which they occur. For any of the specified pairs of load
7039 and store operations (f.ex. load-load, or store-load), all of the first
7040 operations preceding the barrier will complete before any of the second
7041 operations succeeding the barrier begin. Specifically the semantics for each
7042 pairing is as follows:</p>
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7043
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7044<ul>
7045 <li><tt>ll</tt>: All loads before the barrier must complete before any load
7046 after the barrier begins.</li>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]7047 <li><tt>ls</tt>: All loads before the barrier must complete before any
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7048 store after the barrier begins.</li>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]7049 <li><tt>ss</tt>: All stores before the barrier must complete before any
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7050 store after the barrier begins.</li>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]7051 <li><tt>sl</tt>: All stores before the barrier must complete before any
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7052 load after the barrier begins.</li>
7053</ul>
7054
7055<p>These semantics are applied with a logical "and" behavior when more than one
7056 is enabled in a single memory barrier intrinsic.</p>
7057
7058<p>Backends may implement stronger barriers than those requested when they do
7059 not support as fine grained a barrier as requested. Some architectures do
7060 not need all types of barriers and on such architectures, these become
7061 noops.</p>
7062
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7063<h5>Example:</h5>
7064<pre>
Victor Hernandeza70c6df2009-10-26 23:44:29 +0000[diff] [blame]7065%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7066%ptr = bitcast i8* %mallocP to i32*
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7067 store i32 4, %ptr
7068
7069%result1 = load i32* %ptr <i>; yields {i32}:result1 = 4</i>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7070 call void @llvm.memory.barrier(i1 false, i1 true, i1 false, i1 false)
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7071 <i>; guarantee the above finishes</i>
7072 store i32 8, %ptr <i>; before this begins</i>
7073</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7074
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7075</div>
7076
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7077<!-- _______________________________________________________________________ -->
7078<div class="doc_subsubsection">
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7079 <a name="int_atomic_cmp_swap">'<tt>llvm.atomic.cmp.swap.*</tt>' Intrinsic</a>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7080</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7081
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7082<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7083
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7084<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7085<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.cmp.swap</tt> on
7086 any integer bit width and for different address spaces. Not all targets
7087 support all bit widths however.</p>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7088
7089<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7090 declare i8 @llvm.atomic.cmp.swap.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;cmp&gt;, i8 &lt;val&gt;)
7091 declare i16 @llvm.atomic.cmp.swap.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;cmp&gt;, i16 &lt;val&gt;)
7092 declare i32 @llvm.atomic.cmp.swap.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;cmp&gt;, i32 &lt;val&gt;)
7093 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]7094</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7095
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7096<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7097<p>This loads a value in memory and compares it to a given value. If they are
7098 equal, it stores a new value into the memory.</p>
7099
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7100<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7101<p>The <tt>llvm.atomic.cmp.swap</tt> intrinsic takes three arguments. The result
7102 as well as both <tt>cmp</tt> and <tt>val</tt> must be integer values with the
7103 same bit width. The <tt>ptr</tt> argument must be a pointer to a value of
7104 this integer type. While any bit width integer may be used, targets may only
7105 lower representations they support in hardware.</p>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7106
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7107<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7108<p>This entire intrinsic must be executed atomically. It first loads the value
7109 in memory pointed to by <tt>ptr</tt> and compares it with the
7110 value <tt>cmp</tt>. If they are equal, <tt>val</tt> is stored into the
7111 memory. The loaded value is yielded in all cases. This provides the
7112 equivalent of an atomic compare-and-swap operation within the SSA
7113 framework.</p>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7114
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7115<h5>Examples:</h5>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7116<pre>
Victor Hernandeza70c6df2009-10-26 23:44:29 +0000[diff] [blame]7117%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7118%ptr = bitcast i8* %mallocP to i32*
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7119 store i32 4, %ptr
7120
7121%val1 = add i32 4, 4
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7122%result1 = call i32 @llvm.atomic.cmp.swap.i32.p0i32(i32* %ptr, i32 4, %val1)
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7123 <i>; yields {i32}:result1 = 4</i>
7124%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
7125%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
7126
7127%val2 = add i32 1, 1
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7128%result2 = call i32 @llvm.atomic.cmp.swap.i32.p0i32(i32* %ptr, i32 5, %val2)
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7129 <i>; yields {i32}:result2 = 8</i>
7130%stored2 = icmp eq i32 %result2, 5 <i>; yields {i1}:stored2 = false</i>
7131
7132%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 8</i>
7133</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7134
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7135</div>
7136
7137<!-- _______________________________________________________________________ -->
7138<div class="doc_subsubsection">
7139 <a name="int_atomic_swap">'<tt>llvm.atomic.swap.*</tt>' Intrinsic</a>
7140</div>
7141<div class="doc_text">
7142<h5>Syntax:</h5>
7143
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7144<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.swap</tt> on any
7145 integer bit width. Not all targets support all bit widths however.</p>
7146
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7147<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7148 declare i8 @llvm.atomic.swap.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;val&gt;)
7149 declare i16 @llvm.atomic.swap.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;val&gt;)
7150 declare i32 @llvm.atomic.swap.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;val&gt;)
7151 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]7152</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7153
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7154<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7155<p>This intrinsic loads the value stored in memory at <tt>ptr</tt> and yields
7156 the value from memory. It then stores the value in <tt>val</tt> in the memory
7157 at <tt>ptr</tt>.</p>
7158
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7159<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7160<p>The <tt>llvm.atomic.swap</tt> intrinsic takes two arguments. Both
7161 the <tt>val</tt> argument and the result must be integers of the same bit
7162 width. The first argument, <tt>ptr</tt>, must be a pointer to a value of this
7163 integer type. The targets may only lower integer representations they
7164 support.</p>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7165
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7166<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7167<p>This intrinsic loads the value pointed to by <tt>ptr</tt>, yields it, and
7168 stores <tt>val</tt> back into <tt>ptr</tt> atomically. This provides the
7169 equivalent of an atomic swap operation within the SSA framework.</p>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7170
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7171<h5>Examples:</h5>
7172<pre>
Victor Hernandeza70c6df2009-10-26 23:44:29 +0000[diff] [blame]7173%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7174%ptr = bitcast i8* %mallocP to i32*
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7175 store i32 4, %ptr
7176
7177%val1 = add i32 4, 4
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7178%result1 = call i32 @llvm.atomic.swap.i32.p0i32(i32* %ptr, i32 %val1)
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7179 <i>; yields {i32}:result1 = 4</i>
7180%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
7181%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
7182
7183%val2 = add i32 1, 1
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7184%result2 = call i32 @llvm.atomic.swap.i32.p0i32(i32* %ptr, i32 %val2)
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7185 <i>; yields {i32}:result2 = 8</i>
7186
7187%stored2 = icmp eq i32 %result2, 8 <i>; yields {i1}:stored2 = true</i>
7188%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 2</i>
7189</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7190
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7191</div>
7192
7193<!-- _______________________________________________________________________ -->
7194<div class="doc_subsubsection">
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7195 <a name="int_atomic_load_add">'<tt>llvm.atomic.load.add.*</tt>' Intrinsic</a>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7196
7197</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7198
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7199<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7200
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7201<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7202<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.load.add</tt> on
7203 any integer bit width. Not all targets support all bit widths however.</p>
7204
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7205<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7206 declare i8 @llvm.atomic.load.add.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7207 declare i16 @llvm.atomic.load.add.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7208 declare i32 @llvm.atomic.load.add.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7209 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]7210</pre>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7211
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7212<h5>Overview:</h5>
7213<p>This intrinsic adds <tt>delta</tt> to the value stored in memory
7214 at <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.</p>
7215
7216<h5>Arguments:</h5>
7217<p>The intrinsic takes two arguments, the first a pointer to an integer value
7218 and the second an integer value. The result is also an integer value. These
7219 integer types can have any bit width, but they must all have the same bit
7220 width. The targets may only lower integer representations they support.</p>
7221
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7222<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7223<p>This intrinsic does a series of operations atomically. It first loads the
7224 value stored at <tt>ptr</tt>. It then adds <tt>delta</tt>, stores the result
7225 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]7226
7227<h5>Examples:</h5>
7228<pre>
Victor Hernandeza70c6df2009-10-26 23:44:29 +0000[diff] [blame]7229%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7230%ptr = bitcast i8* %mallocP to i32*
7231 store i32 4, %ptr
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7232%result1 = call i32 @llvm.atomic.load.add.i32.p0i32(i32* %ptr, i32 4)
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7233 <i>; yields {i32}:result1 = 4</i>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7234%result2 = call i32 @llvm.atomic.load.add.i32.p0i32(i32* %ptr, i32 2)
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7235 <i>; yields {i32}:result2 = 8</i>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7236%result3 = call i32 @llvm.atomic.load.add.i32.p0i32(i32* %ptr, i32 5)
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7237 <i>; yields {i32}:result3 = 10</i>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7238%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 15</i>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7239</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7240
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7241</div>
7242
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7243<!-- _______________________________________________________________________ -->
7244<div class="doc_subsubsection">
7245 <a name="int_atomic_load_sub">'<tt>llvm.atomic.load.sub.*</tt>' Intrinsic</a>
7246
7247</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7248
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7249<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7250
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7251<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7252<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.load.sub</tt> on
7253 any integer bit width and for different address spaces. Not all targets
7254 support all bit widths however.</p>
7255
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7256<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7257 declare i8 @llvm.atomic.load.sub.i8.p0i32(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7258 declare i16 @llvm.atomic.load.sub.i16.p0i32(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7259 declare i32 @llvm.atomic.load.sub.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7260 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]7261</pre>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7262
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7263<h5>Overview:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]7264<p>This intrinsic subtracts <tt>delta</tt> to the value stored in memory at
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7265 <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.</p>
7266
7267<h5>Arguments:</h5>
7268<p>The intrinsic takes two arguments, the first a pointer to an integer value
7269 and the second an integer value. The result is also an integer value. These
7270 integer types can have any bit width, but they must all have the same bit
7271 width. The targets may only lower integer representations they support.</p>
7272
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7273<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7274<p>This intrinsic does a series of operations atomically. It first loads the
7275 value stored at <tt>ptr</tt>. It then subtracts <tt>delta</tt>, stores the
7276 result to <tt>ptr</tt>. It yields the original value stored
7277 at <tt>ptr</tt>.</p>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7278
7279<h5>Examples:</h5>
7280<pre>
Victor Hernandeza70c6df2009-10-26 23:44:29 +0000[diff] [blame]7281%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7282%ptr = bitcast i8* %mallocP to i32*
7283 store i32 8, %ptr
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7284%result1 = call i32 @llvm.atomic.load.sub.i32.p0i32(i32* %ptr, i32 4)
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7285 <i>; yields {i32}:result1 = 8</i>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7286%result2 = call i32 @llvm.atomic.load.sub.i32.p0i32(i32* %ptr, i32 2)
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7287 <i>; yields {i32}:result2 = 4</i>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7288%result3 = call i32 @llvm.atomic.load.sub.i32.p0i32(i32* %ptr, i32 5)
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7289 <i>; yields {i32}:result3 = 2</i>
7290%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = -3</i>
7291</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7292
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7293</div>
7294
7295<!-- _______________________________________________________________________ -->
7296<div class="doc_subsubsection">
7297 <a name="int_atomic_load_and">'<tt>llvm.atomic.load.and.*</tt>' Intrinsic</a><br>
7298 <a name="int_atomic_load_nand">'<tt>llvm.atomic.load.nand.*</tt>' Intrinsic</a><br>
7299 <a name="int_atomic_load_or">'<tt>llvm.atomic.load.or.*</tt>' Intrinsic</a><br>
7300 <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]7301</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7302
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7303<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7304
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7305<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7306<p>These are overloaded intrinsics. You can
7307 use <tt>llvm.atomic.load_and</tt>, <tt>llvm.atomic.load_nand</tt>,
7308 <tt>llvm.atomic.load_or</tt>, and <tt>llvm.atomic.load_xor</tt> on any integer
7309 bit width and for different address spaces. Not all targets support all bit
7310 widths however.</p>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7311
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7312<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7313 declare i8 @llvm.atomic.load.and.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7314 declare i16 @llvm.atomic.load.and.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7315 declare i32 @llvm.atomic.load.and.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7316 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]7317</pre>
7318
7319<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7320 declare i8 @llvm.atomic.load.or.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7321 declare i16 @llvm.atomic.load.or.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7322 declare i32 @llvm.atomic.load.or.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7323 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]7324</pre>
7325
7326<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7327 declare i8 @llvm.atomic.load.nand.i8.p0i32(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7328 declare i16 @llvm.atomic.load.nand.i16.p0i32(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7329 declare i32 @llvm.atomic.load.nand.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7330 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]7331</pre>
7332
7333<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7334 declare i8 @llvm.atomic.load.xor.i8.p0i32(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7335 declare i16 @llvm.atomic.load.xor.i16.p0i32(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7336 declare i32 @llvm.atomic.load.xor.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7337 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]7338</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7339
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7340<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7341<p>These intrinsics bitwise the operation (and, nand, or, xor) <tt>delta</tt> to
7342 the value stored in memory at <tt>ptr</tt>. It yields the original value
7343 at <tt>ptr</tt>.</p>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7344
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7345<h5>Arguments:</h5>
7346<p>These intrinsics take two arguments, the first a pointer to an integer value
7347 and the second an integer value. The result is also an integer value. These
7348 integer types can have any bit width, but they must all have the same bit
7349 width. The targets may only lower integer representations they support.</p>
7350
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7351<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7352<p>These intrinsics does a series of operations atomically. They first load the
7353 value stored at <tt>ptr</tt>. They then do the bitwise
7354 operation <tt>delta</tt>, store the result to <tt>ptr</tt>. They yield the
7355 original value stored at <tt>ptr</tt>.</p>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7356
7357<h5>Examples:</h5>
7358<pre>
Victor Hernandeza70c6df2009-10-26 23:44:29 +0000[diff] [blame]7359%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7360%ptr = bitcast i8* %mallocP to i32*
7361 store i32 0x0F0F, %ptr
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7362%result0 = call i32 @llvm.atomic.load.nand.i32.p0i32(i32* %ptr, i32 0xFF)
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7363 <i>; yields {i32}:result0 = 0x0F0F</i>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7364%result1 = call i32 @llvm.atomic.load.and.i32.p0i32(i32* %ptr, i32 0xFF)
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7365 <i>; yields {i32}:result1 = 0xFFFFFFF0</i>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7366%result2 = call i32 @llvm.atomic.load.or.i32.p0i32(i32* %ptr, i32 0F)
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7367 <i>; yields {i32}:result2 = 0xF0</i>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7368%result3 = call i32 @llvm.atomic.load.xor.i32.p0i32(i32* %ptr, i32 0F)
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7369 <i>; yields {i32}:result3 = FF</i>
7370%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = F0</i>
7371</pre>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7372
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7373</div>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7374
7375<!-- _______________________________________________________________________ -->
7376<div class="doc_subsubsection">
7377 <a name="int_atomic_load_max">'<tt>llvm.atomic.load.max.*</tt>' Intrinsic</a><br>
7378 <a name="int_atomic_load_min">'<tt>llvm.atomic.load.min.*</tt>' Intrinsic</a><br>
7379 <a name="int_atomic_load_umax">'<tt>llvm.atomic.load.umax.*</tt>' Intrinsic</a><br>
7380 <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]7381</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7382
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7383<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7384
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7385<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7386<p>These are overloaded intrinsics. You can use <tt>llvm.atomic.load_max</tt>,
7387 <tt>llvm.atomic.load_min</tt>, <tt>llvm.atomic.load_umax</tt>, and
7388 <tt>llvm.atomic.load_umin</tt> on any integer bit width and for different
7389 address spaces. Not all targets support all bit widths however.</p>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7390
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7391<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7392 declare i8 @llvm.atomic.load.max.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7393 declare i16 @llvm.atomic.load.max.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7394 declare i32 @llvm.atomic.load.max.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7395 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]7396</pre>
7397
7398<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7399 declare i8 @llvm.atomic.load.min.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7400 declare i16 @llvm.atomic.load.min.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7401 declare i32 @llvm.atomic.load.min.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7402 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]7403</pre>
7404
7405<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7406 declare i8 @llvm.atomic.load.umax.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7407 declare i16 @llvm.atomic.load.umax.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7408 declare i32 @llvm.atomic.load.umax.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7409 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]7410</pre>
7411
7412<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7413 declare i8 @llvm.atomic.load.umin.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7414 declare i16 @llvm.atomic.load.umin.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7415 declare i32 @llvm.atomic.load.umin.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7416 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]7417</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7418
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7419<h5>Overview:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]7420<p>These intrinsics takes the signed or unsigned minimum or maximum of
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7421 <tt>delta</tt> and the value stored in memory at <tt>ptr</tt>. It yields the
7422 original value at <tt>ptr</tt>.</p>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7423
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7424<h5>Arguments:</h5>
7425<p>These intrinsics take two arguments, the first a pointer to an integer value
7426 and the second an integer value. The result is also an integer value. These
7427 integer types can have any bit width, but they must all have the same bit
7428 width. The targets may only lower integer representations they support.</p>
7429
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7430<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7431<p>These intrinsics does a series of operations atomically. They first load the
7432 value stored at <tt>ptr</tt>. They then do the signed or unsigned min or
7433 max <tt>delta</tt> and the value, store the result to <tt>ptr</tt>. They
7434 yield the original value stored at <tt>ptr</tt>.</p>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7435
7436<h5>Examples:</h5>
7437<pre>
Victor Hernandeza70c6df2009-10-26 23:44:29 +0000[diff] [blame]7438%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7439%ptr = bitcast i8* %mallocP to i32*
7440 store i32 7, %ptr
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7441%result0 = call i32 @llvm.atomic.load.min.i32.p0i32(i32* %ptr, i32 -2)
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7442 <i>; yields {i32}:result0 = 7</i>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7443%result1 = call i32 @llvm.atomic.load.max.i32.p0i32(i32* %ptr, i32 8)
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7444 <i>; yields {i32}:result1 = -2</i>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7445%result2 = call i32 @llvm.atomic.load.umin.i32.p0i32(i32* %ptr, i32 10)
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7446 <i>; yields {i32}:result2 = 8</i>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7447%result3 = call i32 @llvm.atomic.load.umax.i32.p0i32(i32* %ptr, i32 30)
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7448 <i>; yields {i32}:result3 = 8</i>
7449%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 30</i>
7450</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7451
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7452</div>
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7453
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]7454
7455<!-- ======================================================================= -->
7456<div class="doc_subsection">
7457 <a name="int_memorymarkers">Memory Use Markers</a>
7458</div>
7459
7460<div class="doc_text">
7461
7462<p>This class of intrinsics exists to information about the lifetime of memory
7463 objects and ranges where variables are immutable.</p>
7464
7465</div>
7466
7467<!-- _______________________________________________________________________ -->
7468<div class="doc_subsubsection">
7469 <a name="int_lifetime_start">'<tt>llvm.lifetime.start</tt>' Intrinsic</a>
7470</div>
7471
7472<div class="doc_text">
7473
7474<h5>Syntax:</h5>
7475<pre>
7476 declare void @llvm.lifetime.start(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7477</pre>
7478
7479<h5>Overview:</h5>
7480<p>The '<tt>llvm.lifetime.start</tt>' intrinsic specifies the start of a memory
7481 object's lifetime.</p>
7482
7483<h5>Arguments:</h5>
Nick Lewycky9bc89042009-10-13 07:57:33 +0000[diff] [blame]7484<p>The first argument is a constant integer representing the size of the
7485 object, or -1 if it is variable sized. The second argument is a pointer to
7486 the object.</p>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]7487
7488<h5>Semantics:</h5>
7489<p>This intrinsic indicates that before this point in the code, the value of the
7490 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]7491 never be used and has an undefined value. A load from the pointer that
7492 precedes this intrinsic can be replaced with
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]7493 <tt>'<a href="#undefvalues">undef</a>'</tt>.</p>
7494
7495</div>
7496
7497<!-- _______________________________________________________________________ -->
7498<div class="doc_subsubsection">
7499 <a name="int_lifetime_end">'<tt>llvm.lifetime.end</tt>' Intrinsic</a>
7500</div>
7501
7502<div class="doc_text">
7503
7504<h5>Syntax:</h5>
7505<pre>
7506 declare void @llvm.lifetime.end(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7507</pre>
7508
7509<h5>Overview:</h5>
7510<p>The '<tt>llvm.lifetime.end</tt>' intrinsic specifies the end of a memory
7511 object's lifetime.</p>
7512
7513<h5>Arguments:</h5>
Nick Lewycky9bc89042009-10-13 07:57:33 +0000[diff] [blame]7514<p>The first argument is a constant integer representing the size of the
7515 object, or -1 if it is variable sized. The second argument is a pointer to
7516 the object.</p>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]7517
7518<h5>Semantics:</h5>
7519<p>This intrinsic indicates that after this point in the code, the value of the
7520 memory pointed to by <tt>ptr</tt> is dead. This means that it is known to
7521 never be used and has an undefined value. Any stores into the memory object
7522 following this intrinsic may be removed as dead.
7523
7524</div>
7525
7526<!-- _______________________________________________________________________ -->
7527<div class="doc_subsubsection">
7528 <a name="int_invariant_start">'<tt>llvm.invariant.start</tt>' Intrinsic</a>
7529</div>
7530
7531<div class="doc_text">
7532
7533<h5>Syntax:</h5>
7534<pre>
7535 declare {}* @llvm.invariant.start(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;) readonly
7536</pre>
7537
7538<h5>Overview:</h5>
7539<p>The '<tt>llvm.invariant.start</tt>' intrinsic specifies that the contents of
7540 a memory object will not change.</p>
7541
7542<h5>Arguments:</h5>
Nick Lewycky9bc89042009-10-13 07:57:33 +0000[diff] [blame]7543<p>The first argument is a constant integer representing the size of the
7544 object, or -1 if it is variable sized. The second argument is a pointer to
7545 the object.</p>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]7546
7547<h5>Semantics:</h5>
7548<p>This intrinsic indicates that until an <tt>llvm.invariant.end</tt> that uses
7549 the return value, the referenced memory location is constant and
7550 unchanging.</p>
7551
7552</div>
7553
7554<!-- _______________________________________________________________________ -->
7555<div class="doc_subsubsection">
7556 <a name="int_invariant_end">'<tt>llvm.invariant.end</tt>' Intrinsic</a>
7557</div>
7558
7559<div class="doc_text">
7560
7561<h5>Syntax:</h5>
7562<pre>
7563 declare void @llvm.invariant.end({}* &lt;start&gt;, i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7564</pre>
7565
7566<h5>Overview:</h5>
7567<p>The '<tt>llvm.invariant.end</tt>' intrinsic specifies that the contents of
7568 a memory object are mutable.</p>
7569
7570<h5>Arguments:</h5>
7571<p>The first argument is the matching <tt>llvm.invariant.start</tt> intrinsic.
Nick Lewycky9bc89042009-10-13 07:57:33 +0000[diff] [blame]7572 The second argument is a constant integer representing the size of the
7573 object, or -1 if it is variable sized and the third argument is a pointer
7574 to the object.</p>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]7575
7576<h5>Semantics:</h5>
7577<p>This intrinsic indicates that the memory is mutable again.</p>
7578
7579</div>
7580
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7581<!-- ======================================================================= -->
7582<div class="doc_subsection">
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]7583 <a name="int_general">General Intrinsics</a>
7584</div>
7585
7586<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7587
7588<p>This class of intrinsics is designed to be generic and has no specific
7589 purpose.</p>
7590
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]7591</div>
7592
7593<!-- _______________________________________________________________________ -->
7594<div class="doc_subsubsection">
7595 <a name="int_var_annotation">'<tt>llvm.var.annotation</tt>' Intrinsic</a>
7596</div>
7597
7598<div class="doc_text">
7599
7600<h5>Syntax:</h5>
7601<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7602 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]7603</pre>
7604
7605<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7606<p>The '<tt>llvm.var.annotation</tt>' intrinsic.</p>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]7607
7608<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7609<p>The first argument is a pointer to a value, the second is a pointer to a
7610 global string, the third is a pointer to a global string which is the source
7611 file name, and the last argument is the line number.</p>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]7612
7613<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7614<p>This intrinsic allows annotation of local variables with arbitrary strings.
7615 This can be useful for special purpose optimizations that want to look for
7616 these annotations. These have no other defined use, they are ignored by code
7617 generation and optimization.</p>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]7618
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]7619</div>
7620
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]7621<!-- _______________________________________________________________________ -->
7622<div class="doc_subsubsection">
Tanya Lattner0186a652007-09-21 23:57:59 +0000[diff] [blame]7623 <a name="int_annotation">'<tt>llvm.annotation.*</tt>' Intrinsic</a>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]7624</div>
7625
7626<div class="doc_text">
7627
7628<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7629<p>This is an overloaded intrinsic. You can use '<tt>llvm.annotation</tt>' on
7630 any integer bit width.</p>
7631
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]7632<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7633 declare i8 @llvm.annotation.i8(i8 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
7634 declare i16 @llvm.annotation.i16(i16 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
7635 declare i32 @llvm.annotation.i32(i32 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
7636 declare i64 @llvm.annotation.i64(i64 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
7637 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]7638</pre>
7639
7640<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7641<p>The '<tt>llvm.annotation</tt>' intrinsic.</p>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]7642
7643<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7644<p>The first argument is an integer value (result of some expression), the
7645 second is a pointer to a global string, the third is a pointer to a global
7646 string which is the source file name, and the last argument is the line
7647 number. It returns the value of the first argument.</p>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]7648
7649<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7650<p>This intrinsic allows annotations to be put on arbitrary expressions with
7651 arbitrary strings. This can be useful for special purpose optimizations that
7652 want to look for these annotations. These have no other defined use, they
7653 are ignored by code generation and optimization.</p>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]7654
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]7655</div>
Jim Laskey2211f492007-03-14 19:31:19 +0000[diff] [blame]7656
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]7657<!-- _______________________________________________________________________ -->
7658<div class="doc_subsubsection">
7659 <a name="int_trap">'<tt>llvm.trap</tt>' Intrinsic</a>
7660</div>
7661
7662<div class="doc_text">
7663
7664<h5>Syntax:</h5>
7665<pre>
7666 declare void @llvm.trap()
7667</pre>
7668
7669<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7670<p>The '<tt>llvm.trap</tt>' intrinsic.</p>
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]7671
7672<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7673<p>None.</p>
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]7674
7675<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7676<p>This intrinsics is lowered to the target dependent trap instruction. If the
7677 target does not have a trap instruction, this intrinsic will be lowered to
7678 the call of the <tt>abort()</tt> function.</p>
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]7679
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]7680</div>
7681
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]7682<!-- _______________________________________________________________________ -->
7683<div class="doc_subsubsection">
Misha Brukman50de2b22008-11-22 23:55:29 +0000[diff] [blame]7684 <a name="int_stackprotector">'<tt>llvm.stackprotector</tt>' Intrinsic</a>
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]7685</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7686
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]7687<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7688
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]7689<h5>Syntax:</h5>
7690<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7691 declare void @llvm.stackprotector(i8* &lt;guard&gt;, i8** &lt;slot&gt;)
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]7692</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7693
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]7694<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7695<p>The <tt>llvm.stackprotector</tt> intrinsic takes the <tt>guard</tt> and
7696 stores it onto the stack at <tt>slot</tt>. The stack slot is adjusted to
7697 ensure that it is placed on the stack before local variables.</p>
7698
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]7699<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7700<p>The <tt>llvm.stackprotector</tt> intrinsic requires two pointer
7701 arguments. The first argument is the value loaded from the stack
7702 guard <tt>@__stack_chk_guard</tt>. The second variable is an <tt>alloca</tt>
7703 that has enough space to hold the value of the guard.</p>
7704
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]7705<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7706<p>This intrinsic causes the prologue/epilogue inserter to force the position of
7707 the <tt>AllocaInst</tt> stack slot to be before local variables on the
7708 stack. This is to ensure that if a local variable on the stack is
7709 overwritten, it will destroy the value of the guard. When the function exits,
7710 the guard on the stack is checked against the original guard. If they're
7711 different, then the program aborts by calling the <tt>__stack_chk_fail()</tt>
7712 function.</p>
7713
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]7714</div>
7715
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]7716<!-- _______________________________________________________________________ -->
7717<div class="doc_subsubsection">
7718 <a name="int_objectsize">'<tt>llvm.objectsize</tt>' Intrinsic</a>
7719</div>
7720
7721<div class="doc_text">
7722
7723<h5>Syntax:</h5>
7724<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7725 declare i32 @llvm.objectsize.i32(i8* &lt;object&gt;, i1 &lt;type&gt;)
7726 declare i64 @llvm.objectsize.i64(i8* &lt;object&gt;, i1 &lt;type&gt;)
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]7727</pre>
7728
7729<h5>Overview:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]7730<p>The <tt>llvm.objectsize</tt> intrinsic is designed to provide information
Eric Christopher3070e162010-01-08 21:42:39 +0000[diff] [blame]7731 to the optimizers to discover at compile time either a) when an
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]7732 operation like memcpy will either overflow a buffer that corresponds to
7733 an object, or b) to determine that a runtime check for overflow isn't
7734 necessary. An object in this context means an allocation of a
Eric Christopher31e39bd2009-12-23 00:29:49 +0000[diff] [blame]7735 specific class, structure, array, or other object.</p>
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]7736
7737<h5>Arguments:</h5>
7738<p>The <tt>llvm.objectsize</tt> intrinsic takes two arguments. The first
Eric Christopher31e39bd2009-12-23 00:29:49 +0000[diff] [blame]7739 argument is a pointer to or into the <tt>object</tt>. The second argument
7740 is a boolean 0 or 1. This argument determines whether you want the
7741 maximum (0) or minimum (1) bytes remaining. This needs to be a literal 0 or
7742 1, variables are not allowed.</p>
7743
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]7744<h5>Semantics:</h5>
7745<p>The <tt>llvm.objectsize</tt> intrinsic is lowered to either a constant
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]7746 representing the size of the object concerned or <tt>i32/i64 -1 or 0</tt>
7747 (depending on the <tt>type</tt> argument if the size cannot be determined
7748 at compile time.</p>
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]7749
7750</div>
7751
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]7752<!-- *********************************************************************** -->
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]7753<hr>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]7754<address>
7755 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
Misha Brukman86242e12008-12-11 17:34:48 +0000[diff] [blame]7756 src="http://jigsaw.w3.org/css-validator/images/vcss-blue" alt="Valid CSS"></a>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]7757 <a href="http://validator.w3.org/check/referer"><img
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Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]7759
7760 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
Reid Spencerca058542006-03-14 05:39:39 +0000[diff] [blame]7761 <a href="http://llvm.org">The LLVM Compiler Infrastructure</a><br>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]7762 Last modified: $Date$
7763</address>
Chris Lattnerb8f816e2008-01-04 04:33:49 +0000[diff] [blame]7764
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]7765</body>
7766</html>