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gerrit-public.fairphone.software / toolchain / llvm-project / 13ee795c428d73b6d15a126143800762f34db3f0 / . / llvm / docs / LangRef.html
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4<head>
5 <title>LLVM Assembly Language Reference Manual</title>
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7 <meta name="author" content="Chris Lattner">
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]8 <meta name="description"
Reid Spencercb84e432004-08-26 20:44:00 +0000[diff] [blame]9 content="LLVM Assembly Language Reference Manual.">
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]10 <link rel="stylesheet" href="llvm.css" type="text/css">
11</head>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]12
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]13<body>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]14
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]15<div class="doc_title"> LLVM Language Reference Manual </div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]16<ol>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]17 <li><a href="#abstract">Abstract</a></li>
18 <li><a href="#introduction">Introduction</a></li>
19 <li><a href="#identifiers">Identifiers</a></li>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]20 <li><a href="#highlevel">High Level Structure</a>
21 <ol>
22 <li><a href="#modulestructure">Module Structure</a></li>
Bill Wendlinga3c6f6b2009-07-20 01:03:30 +0000[diff] [blame]23 <li><a href="#linkage">Linkage Types</a>
24 <ol>
Bill Wendling8693ef82009-07-20 02:41:50 +0000[diff] [blame]25 <li><a href="#linkage_private">'<tt>private</tt>' Linkage</a></li>
26 <li><a href="#linkage_linker_private">'<tt>linker_private</tt>' Linkage</a></li>
Bill Wendling03bcd6e2010-07-01 21:55:59 +0000[diff] [blame]27 <li><a href="#linkage_linker_private_weak">'<tt>linker_private_weak</tt>' Linkage</a></li>
Bill Wendling578ee402010-08-20 22:05:50 +0000[diff] [blame]28 <li><a href="#linkage_linker_private_weak_def_auto">'<tt>linker_private_weak_def_auto</tt>' Linkage</a></li>
Bill Wendling8693ef82009-07-20 02:41:50 +0000[diff] [blame]29 <li><a href="#linkage_internal">'<tt>internal</tt>' Linkage</a></li>
30 <li><a href="#linkage_available_externally">'<tt>available_externally</tt>' Linkage</a></li>
31 <li><a href="#linkage_linkonce">'<tt>linkonce</tt>' Linkage</a></li>
32 <li><a href="#linkage_common">'<tt>common</tt>' Linkage</a></li>
33 <li><a href="#linkage_weak">'<tt>weak</tt>' Linkage</a></li>
34 <li><a href="#linkage_appending">'<tt>appending</tt>' Linkage</a></li>
35 <li><a href="#linkage_externweak">'<tt>extern_weak</tt>' Linkage</a></li>
Chris Lattner80d73c72009-10-10 18:26:06 +0000[diff] [blame]36 <li><a href="#linkage_linkonce_odr">'<tt>linkonce_odr</tt>' Linkage</a></li>
Bill Wendling8693ef82009-07-20 02:41:50 +0000[diff] [blame]37 <li><a href="#linkage_weak">'<tt>weak_odr</tt>' Linkage</a></li>
38 <li><a href="#linkage_external">'<tt>externally visible</tt>' Linkage</a></li>
39 <li><a href="#linkage_dllimport">'<tt>dllimport</tt>' Linkage</a></li>
40 <li><a href="#linkage_dllexport">'<tt>dllexport</tt>' Linkage</a></li>
Bill Wendlinga3c6f6b2009-07-20 01:03:30 +0000[diff] [blame]41 </ol>
42 </li>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]43 <li><a href="#callingconv">Calling Conventions</a></li>
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]44 <li><a href="#namedtypes">Named Types</a></li>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]45 <li><a href="#globalvars">Global Variables</a></li>
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]46 <li><a href="#functionstructure">Functions</a></li>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]47 <li><a href="#aliasstructure">Aliases</a></li>
Devang Pateld1a89692010-01-11 19:35:55 +0000[diff] [blame]48 <li><a href="#namedmetadatastructure">Named Metadata</a></li>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]49 <li><a href="#paramattrs">Parameter Attributes</a></li>
Devang Patel9eb525d2008-09-26 23:51:19 +0000[diff] [blame]50 <li><a href="#fnattrs">Function Attributes</a></li>
Gordon Henriksen71183b62007-12-10 03:18:06 +0000[diff] [blame]51 <li><a href="#gc">Garbage Collector Names</a></li>
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]52 <li><a href="#moduleasm">Module-Level Inline Assembly</a></li>
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]53 <li><a href="#datalayout">Data Layout</a></li>
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]54 <li><a href="#pointeraliasing">Pointer Aliasing Rules</a></li>
Jeffrey Yasskin5d284ae2010-04-26 21:21:24 +0000[diff] [blame]55 <li><a href="#volatile">Volatile Memory Accesses</a></li>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]56 </ol>
57 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]58 <li><a href="#typesystem">Type System</a>
59 <ol>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]60 <li><a href="#t_classifications">Type Classifications</a></li>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]61 <li><a href="#t_primitive">Primitive Types</a>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]62 <ol>
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]63 <li><a href="#t_integer">Integer Type</a></li>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]64 <li><a href="#t_floating">Floating Point Types</a></li>
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>
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]77 <li><a href="#t_vector">Vector Type</a></li>
78 </ol>
79 </li>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]80 <li><a href="#t_function">Function Type</a></li>
81 <li><a href="#t_pointer">Pointer Type</a></li>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]82 <li><a href="#t_opaque">Opaque Type</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]83 </ol>
84 </li>
Chris Lattnercf7a5842009-02-02 07:32:36 +0000[diff] [blame]85 <li><a href="#t_uprefs">Type Up-references</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]86 </ol>
87 </li>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]88 <li><a href="#constants">Constants</a>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]89 <ol>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]90 <li><a href="#simpleconstants">Simple Constants</a></li>
Chris Lattner361bfcd2009-02-28 18:32:25 +0000[diff] [blame]91 <li><a href="#complexconstants">Complex Constants</a></li>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]92 <li><a href="#globalconstants">Global Variable and Function Addresses</a></li>
93 <li><a href="#undefvalues">Undefined Values</a></li>
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]94 <li><a href="#trapvalues">Trap Values</a></li>
Chris Lattner2bfd3202009-10-27 21:19:13 +0000[diff] [blame]95 <li><a href="#blockaddress">Addresses of Basic Blocks</a></li>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]96 <li><a href="#constantexprs">Constant Expressions</a></li>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]97 </ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]98 </li>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]99 <li><a href="#othervalues">Other Values</a>
100 <ol>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]101 <li><a href="#inlineasm">Inline Assembler Expressions</a></li>
Devang Pateld1a89692010-01-11 19:35:55 +0000[diff] [blame]102 <li><a href="#metadata">Metadata Nodes and Metadata Strings</a></li>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]103 </ol>
104 </li>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]105 <li><a href="#intrinsic_globals">Intrinsic Global Variables</a>
106 <ol>
107 <li><a href="#intg_used">The '<tt>llvm.used</tt>' Global Variable</a></li>
Chris Lattner58f9bb22009-07-20 06:14:25 +0000[diff] [blame]108 <li><a href="#intg_compiler_used">The '<tt>llvm.compiler.used</tt>'
109 Global Variable</a></li>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]110 <li><a href="#intg_global_ctors">The '<tt>llvm.global_ctors</tt>'
111 Global Variable</a></li>
112 <li><a href="#intg_global_dtors">The '<tt>llvm.global_dtors</tt>'
113 Global Variable</a></li>
114 </ol>
115 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]116 <li><a href="#instref">Instruction Reference</a>
117 <ol>
118 <li><a href="#terminators">Terminator Instructions</a>
119 <ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]120 <li><a href="#i_ret">'<tt>ret</tt>' Instruction</a></li>
121 <li><a href="#i_br">'<tt>br</tt>' Instruction</a></li>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]122 <li><a href="#i_switch">'<tt>switch</tt>' Instruction</a></li>
Chris Lattnerd04cb6d2009-10-28 00:19:10 +0000[diff] [blame]123 <li><a href="#i_indirectbr">'<tt>indirectbr</tt>' Instruction</a></li>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]124 <li><a href="#i_invoke">'<tt>invoke</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]125 <li><a href="#i_unwind">'<tt>unwind</tt>' Instruction</a></li>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]126 <li><a href="#i_unreachable">'<tt>unreachable</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]127 </ol>
128 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]129 <li><a href="#binaryops">Binary Operations</a>
130 <ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]131 <li><a href="#i_add">'<tt>add</tt>' Instruction</a></li>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]132 <li><a href="#i_fadd">'<tt>fadd</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]133 <li><a href="#i_sub">'<tt>sub</tt>' Instruction</a></li>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]134 <li><a href="#i_fsub">'<tt>fsub</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]135 <li><a href="#i_mul">'<tt>mul</tt>' Instruction</a></li>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]136 <li><a href="#i_fmul">'<tt>fmul</tt>' Instruction</a></li>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]137 <li><a href="#i_udiv">'<tt>udiv</tt>' Instruction</a></li>
138 <li><a href="#i_sdiv">'<tt>sdiv</tt>' Instruction</a></li>
139 <li><a href="#i_fdiv">'<tt>fdiv</tt>' Instruction</a></li>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]140 <li><a href="#i_urem">'<tt>urem</tt>' Instruction</a></li>
141 <li><a href="#i_srem">'<tt>srem</tt>' Instruction</a></li>
142 <li><a href="#i_frem">'<tt>frem</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]143 </ol>
144 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]145 <li><a href="#bitwiseops">Bitwise Binary Operations</a>
146 <ol>
Reid Spencer2ab01932007-02-02 13:57:07 +0000[diff] [blame]147 <li><a href="#i_shl">'<tt>shl</tt>' Instruction</a></li>
148 <li><a href="#i_lshr">'<tt>lshr</tt>' Instruction</a></li>
149 <li><a href="#i_ashr">'<tt>ashr</tt>' Instruction</a></li>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]150 <li><a href="#i_and">'<tt>and</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]151 <li><a href="#i_or">'<tt>or</tt>' Instruction</a></li>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]152 <li><a href="#i_xor">'<tt>xor</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]153 </ol>
154 </li>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]155 <li><a href="#vectorops">Vector Operations</a>
156 <ol>
157 <li><a href="#i_extractelement">'<tt>extractelement</tt>' Instruction</a></li>
158 <li><a href="#i_insertelement">'<tt>insertelement</tt>' Instruction</a></li>
159 <li><a href="#i_shufflevector">'<tt>shufflevector</tt>' Instruction</a></li>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]160 </ol>
161 </li>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]162 <li><a href="#aggregateops">Aggregate Operations</a>
163 <ol>
164 <li><a href="#i_extractvalue">'<tt>extractvalue</tt>' Instruction</a></li>
165 <li><a href="#i_insertvalue">'<tt>insertvalue</tt>' Instruction</a></li>
166 </ol>
167 </li>
Chris Lattner6ab66722006-08-15 00:45:58 +0000[diff] [blame]168 <li><a href="#memoryops">Memory Access and Addressing Operations</a>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]169 <ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]170 <li><a href="#i_alloca">'<tt>alloca</tt>' Instruction</a></li>
Robert Bocchino820bc75b2006-02-17 21:18:08 +0000[diff] [blame]171 <li><a href="#i_load">'<tt>load</tt>' Instruction</a></li>
172 <li><a href="#i_store">'<tt>store</tt>' Instruction</a></li>
173 <li><a href="#i_getelementptr">'<tt>getelementptr</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]174 </ol>
175 </li>
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]176 <li><a href="#convertops">Conversion Operations</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]177 <ol>
178 <li><a href="#i_trunc">'<tt>trunc .. to</tt>' Instruction</a></li>
179 <li><a href="#i_zext">'<tt>zext .. to</tt>' Instruction</a></li>
180 <li><a href="#i_sext">'<tt>sext .. to</tt>' Instruction</a></li>
181 <li><a href="#i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a></li>
182 <li><a href="#i_fpext">'<tt>fpext .. to</tt>' Instruction</a></li>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]183 <li><a href="#i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a></li>
184 <li><a href="#i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a></li>
185 <li><a href="#i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a></li>
186 <li><a href="#i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a></li>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]187 <li><a href="#i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a></li>
188 <li><a href="#i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a></li>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]189 <li><a href="#i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a></li>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]190 </ol>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]191 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]192 <li><a href="#otherops">Other Operations</a>
193 <ol>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]194 <li><a href="#i_icmp">'<tt>icmp</tt>' Instruction</a></li>
195 <li><a href="#i_fcmp">'<tt>fcmp</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]196 <li><a href="#i_phi">'<tt>phi</tt>' Instruction</a></li>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]197 <li><a href="#i_select">'<tt>select</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]198 <li><a href="#i_call">'<tt>call</tt>' Instruction</a></li>
Chris Lattner33337472006-01-13 23:26:01 +0000[diff] [blame]199 <li><a href="#i_va_arg">'<tt>va_arg</tt>' Instruction</a></li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]200 </ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]201 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]202 </ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]203 </li>
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]204 <li><a href="#intrinsics">Intrinsic Functions</a>
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]205 <ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]206 <li><a href="#int_varargs">Variable Argument Handling Intrinsics</a>
207 <ol>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]208 <li><a href="#int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a></li>
209 <li><a href="#int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a></li>
210 <li><a href="#int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]211 </ol>
212 </li>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]213 <li><a href="#int_gc">Accurate Garbage Collection Intrinsics</a>
214 <ol>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]215 <li><a href="#int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a></li>
216 <li><a href="#int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a></li>
217 <li><a href="#int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a></li>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]218 </ol>
219 </li>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]220 <li><a href="#int_codegen">Code Generator Intrinsics</a>
221 <ol>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]222 <li><a href="#int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a></li>
223 <li><a href="#int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a></li>
224 <li><a href="#int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a></li>
225 <li><a href="#int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a></li>
226 <li><a href="#int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a></li>
227 <li><a href="#int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a></li>
Dan Gohmane58f7b32010-05-26 21:56:15 +0000[diff] [blame]228 <li><a href="#int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a></li>
John Criswellaa1c3c12004-04-09 16:43:20 +0000[diff] [blame]229 </ol>
230 </li>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]231 <li><a href="#int_libc">Standard C Library Intrinsics</a>
232 <ol>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]233 <li><a href="#int_memcpy">'<tt>llvm.memcpy.*</tt>' Intrinsic</a></li>
234 <li><a href="#int_memmove">'<tt>llvm.memmove.*</tt>' Intrinsic</a></li>
235 <li><a href="#int_memset">'<tt>llvm.memset.*</tt>' Intrinsic</a></li>
236 <li><a href="#int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a></li>
237 <li><a href="#int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a></li>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]238 <li><a href="#int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a></li>
239 <li><a href="#int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a></li>
240 <li><a href="#int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a></li>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]241 </ol>
242 </li>
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]243 <li><a href="#int_manip">Bit Manipulation Intrinsics</a>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]244 <ol>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]245 <li><a href="#int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a></li>
Chris Lattnerb748c672006-01-16 22:34:14 +0000[diff] [blame]246 <li><a href="#int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic </a></li>
247 <li><a href="#int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic </a></li>
248 <li><a href="#int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic </a></li>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]249 </ol>
250 </li>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]251 <li><a href="#int_overflow">Arithmetic with Overflow Intrinsics</a>
252 <ol>
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]253 <li><a href="#int_sadd_overflow">'<tt>llvm.sadd.with.overflow.*</tt> Intrinsics</a></li>
254 <li><a href="#int_uadd_overflow">'<tt>llvm.uadd.with.overflow.*</tt> Intrinsics</a></li>
255 <li><a href="#int_ssub_overflow">'<tt>llvm.ssub.with.overflow.*</tt> Intrinsics</a></li>
256 <li><a href="#int_usub_overflow">'<tt>llvm.usub.with.overflow.*</tt> Intrinsics</a></li>
257 <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]258 <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]259 </ol>
260 </li>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]261 <li><a href="#int_fp16">Half Precision Floating Point Intrinsics</a>
262 <ol>
Chris Lattnerbbd8bd32010-03-14 23:03:31 +0000[diff] [blame]263 <li><a href="#int_convert_to_fp16">'<tt>llvm.convert.to.fp16</tt>' Intrinsic</a></li>
264 <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]265 </ol>
266 </li>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]267 <li><a href="#int_debugger">Debugger intrinsics</a></li>
Jim Laskey2211f492007-03-14 19:31:19 +0000[diff] [blame]268 <li><a href="#int_eh">Exception Handling intrinsics</a></li>
Duncan Sands86e01192007-09-11 14:10:23 +0000[diff] [blame]269 <li><a href="#int_trampoline">Trampoline Intrinsic</a>
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]270 <ol>
271 <li><a href="#int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a></li>
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]272 </ol>
273 </li>
Bill Wendlingf85850f2008-11-18 22:10:53 +0000[diff] [blame]274 <li><a href="#int_atomics">Atomic intrinsics</a>
275 <ol>
276 <li><a href="#int_memory_barrier"><tt>llvm.memory_barrier</tt></a></li>
277 <li><a href="#int_atomic_cmp_swap"><tt>llvm.atomic.cmp.swap</tt></a></li>
278 <li><a href="#int_atomic_swap"><tt>llvm.atomic.swap</tt></a></li>
279 <li><a href="#int_atomic_load_add"><tt>llvm.atomic.load.add</tt></a></li>
280 <li><a href="#int_atomic_load_sub"><tt>llvm.atomic.load.sub</tt></a></li>
281 <li><a href="#int_atomic_load_and"><tt>llvm.atomic.load.and</tt></a></li>
282 <li><a href="#int_atomic_load_nand"><tt>llvm.atomic.load.nand</tt></a></li>
283 <li><a href="#int_atomic_load_or"><tt>llvm.atomic.load.or</tt></a></li>
284 <li><a href="#int_atomic_load_xor"><tt>llvm.atomic.load.xor</tt></a></li>
285 <li><a href="#int_atomic_load_max"><tt>llvm.atomic.load.max</tt></a></li>
286 <li><a href="#int_atomic_load_min"><tt>llvm.atomic.load.min</tt></a></li>
287 <li><a href="#int_atomic_load_umax"><tt>llvm.atomic.load.umax</tt></a></li>
288 <li><a href="#int_atomic_load_umin"><tt>llvm.atomic.load.umin</tt></a></li>
289 </ol>
290 </li>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]291 <li><a href="#int_memorymarkers">Memory Use Markers</a>
292 <ol>
293 <li><a href="#int_lifetime_start"><tt>llvm.lifetime.start</tt></a></li>
294 <li><a href="#int_lifetime_end"><tt>llvm.lifetime.end</tt></a></li>
295 <li><a href="#int_invariant_start"><tt>llvm.invariant.start</tt></a></li>
296 <li><a href="#int_invariant_end"><tt>llvm.invariant.end</tt></a></li>
297 </ol>
298 </li>
Reid Spencer5b2cb0f2007-07-20 19:59:11 +0000[diff] [blame]299 <li><a href="#int_general">General intrinsics</a>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]300 <ol>
Reid Spencer5b2cb0f2007-07-20 19:59:11 +0000[diff] [blame]301 <li><a href="#int_var_annotation">
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]302 '<tt>llvm.var.annotation</tt>' Intrinsic</a></li>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]303 <li><a href="#int_annotation">
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]304 '<tt>llvm.annotation.*</tt>' Intrinsic</a></li>
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]305 <li><a href="#int_trap">
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]306 '<tt>llvm.trap</tt>' Intrinsic</a></li>
307 <li><a href="#int_stackprotector">
308 '<tt>llvm.stackprotector</tt>' Intrinsic</a></li>
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]309 <li><a href="#int_objectsize">
310 '<tt>llvm.objectsize</tt>' Intrinsic</a></li>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]311 </ol>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]312 </li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]313 </ol>
314 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]315</ol>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]316
317<div class="doc_author">
318 <p>Written by <a href="mailto:sabre@nondot.org">Chris Lattner</a>
319 and <a href="mailto:vadve@cs.uiuc.edu">Vikram Adve</a></p>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]320</div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]321
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]322<!-- *********************************************************************** -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]323<div class="doc_section"> <a name="abstract">Abstract </a></div>
324<!-- *********************************************************************** -->
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]325
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]326<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]327
328<p>This document is a reference manual for the LLVM assembly language. LLVM is
329 a Static Single Assignment (SSA) based representation that provides type
330 safety, low-level operations, flexibility, and the capability of representing
331 'all' high-level languages cleanly. It is the common code representation
332 used throughout all phases of the LLVM compilation strategy.</p>
333
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]334</div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]335
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]336<!-- *********************************************************************** -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]337<div class="doc_section"> <a name="introduction">Introduction</a> </div>
338<!-- *********************************************************************** -->
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]339
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]340<div class="doc_text">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]341
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]342<p>The LLVM code representation is designed to be used in three different forms:
343 as an in-memory compiler IR, as an on-disk bitcode representation (suitable
344 for fast loading by a Just-In-Time compiler), and as a human readable
345 assembly language representation. This allows LLVM to provide a powerful
346 intermediate representation for efficient compiler transformations and
347 analysis, while providing a natural means to debug and visualize the
348 transformations. The three different forms of LLVM are all equivalent. This
349 document describes the human readable representation and notation.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]350
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]351<p>The LLVM representation aims to be light-weight and low-level while being
352 expressive, typed, and extensible at the same time. It aims to be a
353 "universal IR" of sorts, by being at a low enough level that high-level ideas
354 may be cleanly mapped to it (similar to how microprocessors are "universal
355 IR's", allowing many source languages to be mapped to them). By providing
356 type information, LLVM can be used as the target of optimizations: for
357 example, through pointer analysis, it can be proven that a C automatic
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]358 variable is never accessed outside of the current function, allowing it to
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]359 be promoted to a simple SSA value instead of a memory location.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]360
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]361</div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]362
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]363<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]364<div class="doc_subsubsection"> <a name="wellformed">Well-Formedness</a> </div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]365
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]366<div class="doc_text">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]367
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]368<p>It is important to note that this document describes 'well formed' LLVM
369 assembly language. There is a difference between what the parser accepts and
370 what is considered 'well formed'. For example, the following instruction is
371 syntactically okay, but not well formed:</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]372
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]373<pre class="doc_code">
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]374%x = <a href="#i_add">add</a> i32 1, %x
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]375</pre>
376
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]377<p>because the definition of <tt>%x</tt> does not dominate all of its uses. The
378 LLVM infrastructure provides a verification pass that may be used to verify
379 that an LLVM module is well formed. This pass is automatically run by the
380 parser after parsing input assembly and by the optimizer before it outputs
381 bitcode. The violations pointed out by the verifier pass indicate bugs in
382 transformation passes or input to the parser.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]383
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]384</div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]385
Chris Lattner87a3dbe2007-10-03 17:34:29 +0000[diff] [blame]386<!-- Describe the typesetting conventions here. -->
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]387
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]388<!-- *********************************************************************** -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]389<div class="doc_section"> <a name="identifiers">Identifiers</a> </div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]390<!-- *********************************************************************** -->
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]391
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]392<div class="doc_text">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]393
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]394<p>LLVM identifiers come in two basic types: global and local. Global
395 identifiers (functions, global variables) begin with the <tt>'@'</tt>
396 character. Local identifiers (register names, types) begin with
397 the <tt>'%'</tt> character. Additionally, there are three different formats
398 for identifiers, for different purposes:</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]399
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]400<ol>
Reid Spencerb23b65f2007-08-07 14:34:28 +0000[diff] [blame]401 <li>Named values are represented as a string of characters with their prefix.
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]402 For example, <tt>%foo</tt>, <tt>@DivisionByZero</tt>,
403 <tt>%a.really.long.identifier</tt>. The actual regular expression used is
404 '<tt>[%@][a-zA-Z$._][a-zA-Z$._0-9]*</tt>'. Identifiers which require
405 other characters in their names can be surrounded with quotes. Special
406 characters may be escaped using <tt>"\xx"</tt> where <tt>xx</tt> is the
407 ASCII code for the character in hexadecimal. In this way, any character
408 can be used in a name value, even quotes themselves.</li>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]409
Reid Spencerb23b65f2007-08-07 14:34:28 +0000[diff] [blame]410 <li>Unnamed values are represented as an unsigned numeric value with their
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]411 prefix. For example, <tt>%12</tt>, <tt>@2</tt>, <tt>%44</tt>.</li>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]412
Reid Spencer8f08d802004-12-09 18:02:53 +0000[diff] [blame]413 <li>Constants, which are described in a <a href="#constants">section about
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]414 constants</a>, below.</li>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]415</ol>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]416
Reid Spencerb23b65f2007-08-07 14:34:28 +0000[diff] [blame]417<p>LLVM requires that values start with a prefix for two reasons: Compilers
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]418 don't need to worry about name clashes with reserved words, and the set of
419 reserved words may be expanded in the future without penalty. Additionally,
420 unnamed identifiers allow a compiler to quickly come up with a temporary
421 variable without having to avoid symbol table conflicts.</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]422
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]423<p>Reserved words in LLVM are very similar to reserved words in other
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]424 languages. There are keywords for different opcodes
425 ('<tt><a href="#i_add">add</a></tt>',
426 '<tt><a href="#i_bitcast">bitcast</a></tt>',
427 '<tt><a href="#i_ret">ret</a></tt>', etc...), for primitive type names
428 ('<tt><a href="#t_void">void</a></tt>',
429 '<tt><a href="#t_primitive">i32</a></tt>', etc...), and others. These
430 reserved words cannot conflict with variable names, because none of them
431 start with a prefix character (<tt>'%'</tt> or <tt>'@'</tt>).</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]432
433<p>Here is an example of LLVM code to multiply the integer variable
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]434 '<tt>%X</tt>' by 8:</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]435
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]436<p>The easy way:</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]437
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]438<pre class="doc_code">
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]439%result = <a href="#i_mul">mul</a> i32 %X, 8
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]440</pre>
441
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]442<p>After strength reduction:</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]443
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]444<pre class="doc_code">
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]445%result = <a href="#i_shl">shl</a> i32 %X, i8 3
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]446</pre>
447
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]448<p>And the hard way:</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]449
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]450<pre class="doc_code">
Gabor Greifbd0328f2009-10-28 13:05:07 +0000[diff] [blame]451%0 = <a href="#i_add">add</a> i32 %X, %X <i>; yields {i32}:%0</i>
452%1 = <a href="#i_add">add</a> i32 %0, %0 <i>; yields {i32}:%1</i>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]453%result = <a href="#i_add">add</a> i32 %1, %1
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]454</pre>
455
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]456<p>This last way of multiplying <tt>%X</tt> by 8 illustrates several important
457 lexical features of LLVM:</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]458
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]459<ol>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]460 <li>Comments are delimited with a '<tt>;</tt>' and go until the end of
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]461 line.</li>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]462
463 <li>Unnamed temporaries are created when the result of a computation is not
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]464 assigned to a named value.</li>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]465
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]466 <li>Unnamed temporaries are numbered sequentially</li>
467</ol>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]468
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]469<p>It also shows a convention that we follow in this document. When
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]470 demonstrating instructions, we will follow an instruction with a comment that
471 defines the type and name of value produced. Comments are shown in italic
472 text.</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]473
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]474</div>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]475
476<!-- *********************************************************************** -->
477<div class="doc_section"> <a name="highlevel">High Level Structure</a> </div>
478<!-- *********************************************************************** -->
479
480<!-- ======================================================================= -->
481<div class="doc_subsection"> <a name="modulestructure">Module Structure</a>
482</div>
483
484<div class="doc_text">
485
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]486<p>LLVM programs are composed of "Module"s, each of which is a translation unit
487 of the input programs. Each module consists of functions, global variables,
488 and symbol table entries. Modules may be combined together with the LLVM
489 linker, which merges function (and global variable) definitions, resolves
490 forward declarations, and merges symbol table entries. Here is an example of
491 the "hello world" module:</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]492
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]493<pre class="doc_code">
Chris Lattner54a7be72010-08-17 17:13:42 +0000[diff] [blame]494<i>; Declare the string constant as a global constant.</i>&nbsp;
495<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]496
Chris Lattner54a7be72010-08-17 17:13:42 +0000[diff] [blame]497<i>; External declaration of the puts function</i>&nbsp;
498<a href="#functionstructure">declare</a> i32 @puts(i8*) <i>; i32 (i8*)* </i>&nbsp;
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]499
500<i>; Definition of main function</i>
Chris Lattner54a7be72010-08-17 17:13:42 +0000[diff] [blame]501define i32 @main() { <i>; i32()* </i>&nbsp;
502 <i>; Convert [13 x i8]* to i8 *...</i>&nbsp;
503 %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]504
Chris Lattner54a7be72010-08-17 17:13:42 +0000[diff] [blame]505 <i>; Call puts function to write out the string to stdout.</i>&nbsp;
506 <a href="#i_call">call</a> i32 @puts(i8* %cast210) <i>; i32</i>&nbsp;
507 <a href="#i_ret">ret</a> i32 0&nbsp;
508}
Devang Pateld1a89692010-01-11 19:35:55 +0000[diff] [blame]509
510<i>; Named metadata</i>
511!1 = metadata !{i32 41}
512!foo = !{!1, null}
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]513</pre>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]514
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]515<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]516 "<tt>.LC0</tt>", an external declaration of the "<tt>puts</tt>" function,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]517 a <a href="#functionstructure">function definition</a> for
Devang Pateld1a89692010-01-11 19:35:55 +0000[diff] [blame]518 "<tt>main</tt>" and <a href="#namedmetadatastructure">named metadata</a>
519 "<tt>foo"</tt>.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]520
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]521<p>In general, a module is made up of a list of global values, where both
522 functions and global variables are global values. Global values are
523 represented by a pointer to a memory location (in this case, a pointer to an
524 array of char, and a pointer to a function), and have one of the
525 following <a href="#linkage">linkage types</a>.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]526
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]527</div>
528
529<!-- ======================================================================= -->
530<div class="doc_subsection">
531 <a name="linkage">Linkage Types</a>
532</div>
533
534<div class="doc_text">
535
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]536<p>All Global Variables and Functions have one of the following types of
537 linkage:</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]538
539<dl>
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]540 <dt><tt><b><a name="linkage_private">private</a></b></tt></dt>
Bill Wendling03bcd6e2010-07-01 21:55:59 +0000[diff] [blame]541 <dd>Global values with "<tt>private</tt>" linkage are only directly accessible
542 by objects in the current module. In particular, linking code into a
543 module with an private global value may cause the private to be renamed as
544 necessary to avoid collisions. Because the symbol is private to the
545 module, all references can be updated. This doesn't show up in any symbol
546 table in the object file.</dd>
Rafael Espindola6de96a12009-01-15 20:18:42 +0000[diff] [blame]547
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]548 <dt><tt><b><a name="linkage_linker_private">linker_private</a></b></tt></dt>
Bill Wendling03bcd6e2010-07-01 21:55:59 +0000[diff] [blame]549 <dd>Similar to <tt>private</tt>, but the symbol is passed through the
550 assembler and evaluated by the linker. Unlike normal strong symbols, they
551 are removed by the linker from the final linked image (executable or
552 dynamic library).</dd>
553
554 <dt><tt><b><a name="linkage_linker_private_weak">linker_private_weak</a></b></tt></dt>
555 <dd>Similar to "<tt>linker_private</tt>", but the symbol is weak. Note that
556 <tt>linker_private_weak</tt> symbols are subject to coalescing by the
557 linker. The symbols are removed by the linker from the final linked image
558 (executable or dynamic library).</dd>
Bill Wendlinga3c6f6b2009-07-20 01:03:30 +0000[diff] [blame]559
Bill Wendling578ee402010-08-20 22:05:50 +0000[diff] [blame]560 <dt><tt><b><a name="linkage_linker_private_weak_def_auto">linker_private_weak_def_auto</a></b></tt></dt>
561 <dd>Similar to "<tt>linker_private_weak</tt>", but it's known that the address
562 of the object is not taken. For instance, functions that had an inline
563 definition, but the compiler decided not to inline it. Note,
564 unlike <tt>linker_private</tt> and <tt>linker_private_weak</tt>,
565 <tt>linker_private_weak_def_auto</tt> may have only <tt>default</tt>
566 visibility. The symbols are removed by the linker from the final linked
567 image (executable or dynamic library).</dd>
568
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]569 <dt><tt><b><a name="linkage_internal">internal</a></b></tt></dt>
Bill Wendling36321712010-06-29 22:34:52 +0000[diff] [blame]570 <dd>Similar to private, but the value shows as a local symbol
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]571 (<tt>STB_LOCAL</tt> in the case of ELF) in the object file. This
572 corresponds to the notion of the '<tt>static</tt>' keyword in C.</dd>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]573
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]574 <dt><tt><b><a name="linkage_available_externally">available_externally</a></b></tt></dt>
Chris Lattner184f1be2009-04-13 05:44:34 +0000[diff] [blame]575 <dd>Globals with "<tt>available_externally</tt>" linkage are never emitted
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]576 into the object file corresponding to the LLVM module. They exist to
577 allow inlining and other optimizations to take place given knowledge of
578 the definition of the global, which is known to be somewhere outside the
579 module. Globals with <tt>available_externally</tt> linkage are allowed to
580 be discarded at will, and are otherwise the same as <tt>linkonce_odr</tt>.
581 This linkage type is only allowed on definitions, not declarations.</dd>
Chris Lattner184f1be2009-04-13 05:44:34 +0000[diff] [blame]582
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]583 <dt><tt><b><a name="linkage_linkonce">linkonce</a></b></tt></dt>
Chris Lattnere20b4702007-01-14 06:51:48 +0000[diff] [blame]584 <dd>Globals with "<tt>linkonce</tt>" linkage are merged with other globals of
Chris Lattner0de4caa2010-01-09 19:15:14 +0000[diff] [blame]585 the same name when linkage occurs. This can be used to implement
586 some forms of inline functions, templates, or other code which must be
587 generated in each translation unit that uses it, but where the body may
588 be overridden with a more definitive definition later. Unreferenced
589 <tt>linkonce</tt> globals are allowed to be discarded. Note that
590 <tt>linkonce</tt> linkage does not actually allow the optimizer to
591 inline the body of this function into callers because it doesn't know if
592 this definition of the function is the definitive definition within the
593 program or whether it will be overridden by a stronger definition.
594 To enable inlining and other optimizations, use "<tt>linkonce_odr</tt>"
595 linkage.</dd>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]596
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]597 <dt><tt><b><a name="linkage_weak">weak</a></b></tt></dt>
Chris Lattnerd0554882009-08-05 05:21:07 +0000[diff] [blame]598 <dd>"<tt>weak</tt>" linkage has the same merging semantics as
599 <tt>linkonce</tt> linkage, except that unreferenced globals with
600 <tt>weak</tt> linkage may not be discarded. This is used for globals that
601 are declared "weak" in C source code.</dd>
602
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]603 <dt><tt><b><a name="linkage_common">common</a></b></tt></dt>
Chris Lattnerd0554882009-08-05 05:21:07 +0000[diff] [blame]604 <dd>"<tt>common</tt>" linkage is most similar to "<tt>weak</tt>" linkage, but
605 they are used for tentative definitions in C, such as "<tt>int X;</tt>" at
606 global scope.
607 Symbols with "<tt>common</tt>" linkage are merged in the same way as
608 <tt>weak symbols</tt>, and they may not be deleted if unreferenced.
Chris Lattner0aff0b22009-08-05 05:41:44 +0000[diff] [blame]609 <tt>common</tt> symbols may not have an explicit section,
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]610 must have a zero initializer, and may not be marked '<a
Chris Lattner0aff0b22009-08-05 05:41:44 +0000[diff] [blame]611 href="#globalvars"><tt>constant</tt></a>'. Functions and aliases may not
612 have common linkage.</dd>
Chris Lattnerd0554882009-08-05 05:21:07 +0000[diff] [blame]613
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]614
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]615 <dt><tt><b><a name="linkage_appending">appending</a></b></tt></dt>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]616 <dd>"<tt>appending</tt>" linkage may only be applied to global variables of
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]617 pointer to array type. When two global variables with appending linkage
618 are linked together, the two global arrays are appended together. This is
619 the LLVM, typesafe, equivalent of having the system linker append together
620 "sections" with identical names when .o files are linked.</dd>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]621
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]622 <dt><tt><b><a name="linkage_externweak">extern_weak</a></b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]623 <dd>The semantics of this linkage follow the ELF object file model: the symbol
624 is weak until linked, if not linked, the symbol becomes null instead of
625 being an undefined reference.</dd>
Anton Korobeynikova0554d92007-01-12 19:20:47 +0000[diff] [blame]626
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]627 <dt><tt><b><a name="linkage_linkonce_odr">linkonce_odr</a></b></tt></dt>
628 <dt><tt><b><a name="linkage_weak_odr">weak_odr</a></b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]629 <dd>Some languages allow differing globals to be merged, such as two functions
630 with different semantics. Other languages, such as <tt>C++</tt>, ensure
Bill Wendling03bcd6e2010-07-01 21:55:59 +0000[diff] [blame]631 that only equivalent globals are ever merged (the "one definition rule"
632 &mdash; "ODR"). Such languages can use the <tt>linkonce_odr</tt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]633 and <tt>weak_odr</tt> linkage types to indicate that the global will only
634 be merged with equivalent globals. These linkage types are otherwise the
635 same as their non-<tt>odr</tt> versions.</dd>
Duncan Sands12da8ce2009-03-07 15:45:40 +0000[diff] [blame]636
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]637 <dt><tt><b><a name="linkage_external">externally visible</a></b></tt>:</dt>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]638 <dd>If none of the above identifiers are used, the global is externally
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]639 visible, meaning that it participates in linkage and can be used to
640 resolve external symbol references.</dd>
Reid Spencer7972c472007-04-11 23:49:50 +0000[diff] [blame]641</dl>
Anton Korobeynikovd61d39e2006-09-14 18:23:27 +0000[diff] [blame]642
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]643<p>The next two types of linkage are targeted for Microsoft Windows platform
644 only. They are designed to support importing (exporting) symbols from (to)
645 DLLs (Dynamic Link Libraries).</p>
Anton Korobeynikovd61d39e2006-09-14 18:23:27 +0000[diff] [blame]646
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]647<dl>
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]648 <dt><tt><b><a name="linkage_dllimport">dllimport</a></b></tt></dt>
Anton Korobeynikovd61d39e2006-09-14 18:23:27 +0000[diff] [blame]649 <dd>"<tt>dllimport</tt>" linkage causes the compiler to reference a function
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]650 or variable via a global pointer to a pointer that is set up by the DLL
651 exporting the symbol. On Microsoft Windows targets, the pointer name is
652 formed by combining <code>__imp_</code> and the function or variable
653 name.</dd>
Anton Korobeynikovd61d39e2006-09-14 18:23:27 +0000[diff] [blame]654
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]655 <dt><tt><b><a name="linkage_dllexport">dllexport</a></b></tt></dt>
Anton Korobeynikovd61d39e2006-09-14 18:23:27 +0000[diff] [blame]656 <dd>"<tt>dllexport</tt>" linkage causes the compiler to provide a global
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]657 pointer to a pointer in a DLL, so that it can be referenced with the
658 <tt>dllimport</tt> attribute. On Microsoft Windows targets, the pointer
659 name is formed by combining <code>__imp_</code> and the function or
660 variable name.</dd>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]661</dl>
662
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]663<p>For example, since the "<tt>.LC0</tt>" variable is defined to be internal, if
664 another module defined a "<tt>.LC0</tt>" variable and was linked with this
665 one, one of the two would be renamed, preventing a collision. Since
666 "<tt>main</tt>" and "<tt>puts</tt>" are external (i.e., lacking any linkage
667 declarations), they are accessible outside of the current module.</p>
668
669<p>It is illegal for a function <i>declaration</i> to have any linkage type
670 other than "externally visible", <tt>dllimport</tt>
671 or <tt>extern_weak</tt>.</p>
672
Duncan Sands12da8ce2009-03-07 15:45:40 +0000[diff] [blame]673<p>Aliases can have only <tt>external</tt>, <tt>internal</tt>, <tt>weak</tt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]674 or <tt>weak_odr</tt> linkages.</p>
675
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]676</div>
677
678<!-- ======================================================================= -->
679<div class="doc_subsection">
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]680 <a name="callingconv">Calling Conventions</a>
681</div>
682
683<div class="doc_text">
684
685<p>LLVM <a href="#functionstructure">functions</a>, <a href="#i_call">calls</a>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]686 and <a href="#i_invoke">invokes</a> can all have an optional calling
687 convention specified for the call. The calling convention of any pair of
688 dynamic caller/callee must match, or the behavior of the program is
689 undefined. The following calling conventions are supported by LLVM, and more
690 may be added in the future:</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]691
692<dl>
693 <dt><b>"<tt>ccc</tt>" - The C calling convention</b>:</dt>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]694 <dd>This calling convention (the default if no other calling convention is
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]695 specified) matches the target C calling conventions. This calling
696 convention supports varargs function calls and tolerates some mismatch in
697 the declared prototype and implemented declaration of the function (as
698 does normal C).</dd>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]699
700 <dt><b>"<tt>fastcc</tt>" - The fast calling convention</b>:</dt>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]701 <dd>This calling convention attempts to make calls as fast as possible
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]702 (e.g. by passing things in registers). This calling convention allows the
703 target to use whatever tricks it wants to produce fast code for the
704 target, without having to conform to an externally specified ABI
Jeffrey Yasskinb8677462010-01-09 19:44:16 +0000[diff] [blame]705 (Application Binary Interface).
706 <a href="CodeGenerator.html#tailcallopt">Tail calls can only be optimized
Chris Lattnera179e4d2010-03-11 00:22:57 +0000[diff] [blame]707 when this or the GHC convention is used.</a> This calling convention
708 does not support varargs and requires the prototype of all callees to
709 exactly match the prototype of the function definition.</dd>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]710
711 <dt><b>"<tt>coldcc</tt>" - The cold calling convention</b>:</dt>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]712 <dd>This calling convention attempts to make code in the caller as efficient
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]713 as possible under the assumption that the call is not commonly executed.
714 As such, these calls often preserve all registers so that the call does
715 not break any live ranges in the caller side. This calling convention
716 does not support varargs and requires the prototype of all callees to
717 exactly match the prototype of the function definition.</dd>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]718
Chris Lattnera179e4d2010-03-11 00:22:57 +0000[diff] [blame]719 <dt><b>"<tt>cc <em>10</em></tt>" - GHC convention</b>:</dt>
720 <dd>This calling convention has been implemented specifically for use by the
721 <a href="http://www.haskell.org/ghc">Glasgow Haskell Compiler (GHC)</a>.
722 It passes everything in registers, going to extremes to achieve this by
723 disabling callee save registers. This calling convention should not be
724 used lightly but only for specific situations such as an alternative to
725 the <em>register pinning</em> performance technique often used when
726 implementing functional programming languages.At the moment only X86
727 supports this convention and it has the following limitations:
728 <ul>
729 <li>On <em>X86-32</em> only supports up to 4 bit type parameters. No
730 floating point types are supported.</li>
731 <li>On <em>X86-64</em> only supports up to 10 bit type parameters and
732 6 floating point parameters.</li>
733 </ul>
734 This calling convention supports
735 <a href="CodeGenerator.html#tailcallopt">tail call optimization</a> but
736 requires both the caller and callee are using it.
737 </dd>
738
Chris Lattner573f64e2005-05-07 01:46:40 +0000[diff] [blame]739 <dt><b>"<tt>cc &lt;<em>n</em>&gt;</tt>" - Numbered convention</b>:</dt>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]740 <dd>Any calling convention may be specified by number, allowing
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]741 target-specific calling conventions to be used. Target specific calling
742 conventions start at 64.</dd>
Chris Lattner573f64e2005-05-07 01:46:40 +0000[diff] [blame]743</dl>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]744
745<p>More calling conventions can be added/defined on an as-needed basis, to
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]746 support Pascal conventions or any other well-known target-independent
747 convention.</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]748
749</div>
750
751<!-- ======================================================================= -->
752<div class="doc_subsection">
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]753 <a name="visibility">Visibility Styles</a>
754</div>
755
756<div class="doc_text">
757
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]758<p>All Global Variables and Functions have one of the following visibility
759 styles:</p>
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]760
761<dl>
762 <dt><b>"<tt>default</tt>" - Default style</b>:</dt>
Chris Lattner67c37d12008-08-05 18:29:16 +0000[diff] [blame]763 <dd>On targets that use the ELF object file format, default visibility means
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]764 that the declaration is visible to other modules and, in shared libraries,
765 means that the declared entity may be overridden. On Darwin, default
766 visibility means that the declaration is visible to other modules. Default
767 visibility corresponds to "external linkage" in the language.</dd>
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]768
769 <dt><b>"<tt>hidden</tt>" - Hidden style</b>:</dt>
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]770 <dd>Two declarations of an object with hidden visibility refer to the same
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]771 object if they are in the same shared object. Usually, hidden visibility
772 indicates that the symbol will not be placed into the dynamic symbol
773 table, so no other module (executable or shared library) can reference it
774 directly.</dd>
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]775
Anton Korobeynikov39f3cff2007-04-29 18:35:00 +0000[diff] [blame]776 <dt><b>"<tt>protected</tt>" - Protected style</b>:</dt>
Anton Korobeynikov39f3cff2007-04-29 18:35:00 +0000[diff] [blame]777 <dd>On ELF, protected visibility indicates that the symbol will be placed in
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]778 the dynamic symbol table, but that references within the defining module
779 will bind to the local symbol. That is, the symbol cannot be overridden by
780 another module.</dd>
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]781</dl>
782
783</div>
784
785<!-- ======================================================================= -->
786<div class="doc_subsection">
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]787 <a name="namedtypes">Named Types</a>
788</div>
789
790<div class="doc_text">
791
792<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]793 it easier to read the IR and make the IR more condensed (particularly when
794 recursive types are involved). An example of a name specification is:</p>
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]795
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]796<pre class="doc_code">
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]797%mytype = type { %mytype*, i32 }
798</pre>
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]799
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]800<p>You may give a name to any <a href="#typesystem">type</a> except
Chris Lattner249b9762010-08-17 23:26:04 +0000[diff] [blame]801 "<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]802 is expected with the syntax "%mytype".</p>
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]803
804<p>Note that type names are aliases for the structural type that they indicate,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]805 and that you can therefore specify multiple names for the same type. This
806 often leads to confusing behavior when dumping out a .ll file. Since LLVM IR
807 uses structural typing, the name is not part of the type. When printing out
808 LLVM IR, the printer will pick <em>one name</em> to render all types of a
809 particular shape. This means that if you have code where two different
810 source types end up having the same LLVM type, that the dumper will sometimes
811 print the "wrong" or unexpected type. This is an important design point and
812 isn't going to change.</p>
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]813
814</div>
815
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]816<!-- ======================================================================= -->
817<div class="doc_subsection">
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]818 <a name="globalvars">Global Variables</a>
819</div>
820
821<div class="doc_text">
822
Chris Lattner5d5aede2005-02-12 19:30:21 +0000[diff] [blame]823<p>Global variables define regions of memory allocated at compilation time
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]824 instead of run-time. Global variables may optionally be initialized, may
825 have an explicit section to be placed in, and may have an optional explicit
826 alignment specified. A variable may be defined as "thread_local", which
827 means that it will not be shared by threads (each thread will have a
828 separated copy of the variable). A variable may be defined as a global
829 "constant," which indicates that the contents of the variable
830 will <b>never</b> be modified (enabling better optimization, allowing the
831 global data to be placed in the read-only section of an executable, etc).
832 Note that variables that need runtime initialization cannot be marked
833 "constant" as there is a store to the variable.</p>
Chris Lattner5d5aede2005-02-12 19:30:21 +0000[diff] [blame]834
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]835<p>LLVM explicitly allows <em>declarations</em> of global variables to be marked
836 constant, even if the final definition of the global is not. This capability
837 can be used to enable slightly better optimization of the program, but
838 requires the language definition to guarantee that optimizations based on the
839 'constantness' are valid for the translation units that do not include the
840 definition.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]841
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]842<p>As SSA values, global variables define pointer values that are in scope
843 (i.e. they dominate) all basic blocks in the program. Global variables
844 always define a pointer to their "content" type because they describe a
845 region of memory, and all memory objects in LLVM are accessed through
846 pointers.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]847
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]848<p>A global variable may be declared to reside in a target-specific numbered
849 address space. For targets that support them, address spaces may affect how
850 optimizations are performed and/or what target instructions are used to
851 access the variable. The default address space is zero. The address space
852 qualifier must precede any other attributes.</p>
Christopher Lamb308121c2007-12-11 09:31:00 +0000[diff] [blame]853
Chris Lattner662c8722005-11-12 00:45:07 +0000[diff] [blame]854<p>LLVM allows an explicit section to be specified for globals. If the target
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]855 supports it, it will emit globals to the section specified.</p>
Chris Lattner662c8722005-11-12 00:45:07 +0000[diff] [blame]856
Chris Lattner78e00bc2010-04-28 00:13:42 +0000[diff] [blame]857<p>An explicit alignment may be specified for a global, which must be a power
858 of 2. If not present, or if the alignment is set to zero, the alignment of
859 the global is set by the target to whatever it feels convenient. If an
860 explicit alignment is specified, the global is forced to have exactly that
Chris Lattner4bd85e42010-04-28 00:31:12 +0000[diff] [blame]861 alignment. Targets and optimizers are not allowed to over-align the global
862 if the global has an assigned section. In this case, the extra alignment
863 could be observable: for example, code could assume that the globals are
864 densely packed in their section and try to iterate over them as an array,
865 alignment padding would break this iteration.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]866
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]867<p>For example, the following defines a global in a numbered address space with
868 an initializer, section, and alignment:</p>
Chris Lattner5760c502007-01-14 00:27:09 +0000[diff] [blame]869
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]870<pre class="doc_code">
Dan Gohmanaaa679b2009-01-11 00:40:00 +0000[diff] [blame]871@G = addrspace(5) constant float 1.0, section "foo", align 4
Chris Lattner5760c502007-01-14 00:27:09 +0000[diff] [blame]872</pre>
873
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]874</div>
875
876
877<!-- ======================================================================= -->
878<div class="doc_subsection">
879 <a name="functionstructure">Functions</a>
880</div>
881
882<div class="doc_text">
883
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]884<p>LLVM function definitions consist of the "<tt>define</tt>" keyword, an
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]885 optional <a href="#linkage">linkage type</a>, an optional
886 <a href="#visibility">visibility style</a>, an optional
887 <a href="#callingconv">calling convention</a>, a return type, an optional
888 <a href="#paramattrs">parameter attribute</a> for the return type, a function
889 name, a (possibly empty) argument list (each with optional
890 <a href="#paramattrs">parameter attributes</a>), optional
891 <a href="#fnattrs">function attributes</a>, an optional section, an optional
892 alignment, an optional <a href="#gc">garbage collector name</a>, an opening
893 curly brace, a list of basic blocks, and a closing curly brace.</p>
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]894
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]895<p>LLVM function declarations consist of the "<tt>declare</tt>" keyword, an
896 optional <a href="#linkage">linkage type</a>, an optional
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]897 <a href="#visibility">visibility style</a>, an optional
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]898 <a href="#callingconv">calling convention</a>, a return type, an optional
899 <a href="#paramattrs">parameter attribute</a> for the return type, a function
900 name, a possibly empty list of arguments, an optional alignment, and an
901 optional <a href="#gc">garbage collector name</a>.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]902
Chris Lattner67c37d12008-08-05 18:29:16 +0000[diff] [blame]903<p>A function definition contains a list of basic blocks, forming the CFG
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]904 (Control Flow Graph) for the function. Each basic block may optionally start
905 with a label (giving the basic block a symbol table entry), contains a list
906 of instructions, and ends with a <a href="#terminators">terminator</a>
907 instruction (such as a branch or function return).</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]908
Chris Lattnera59fb102007-06-08 16:52:14 +0000[diff] [blame]909<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]910 executed on entrance to the function, and it is not allowed to have
911 predecessor basic blocks (i.e. there can not be any branches to the entry
912 block of a function). Because the block can have no predecessors, it also
913 cannot have any <a href="#i_phi">PHI nodes</a>.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]914
Chris Lattner662c8722005-11-12 00:45:07 +0000[diff] [blame]915<p>LLVM allows an explicit section to be specified for functions. If the target
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]916 supports it, it will emit functions to the section specified.</p>
Chris Lattner662c8722005-11-12 00:45:07 +0000[diff] [blame]917
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]918<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]919 the alignment is set to zero, the alignment of the function is set by the
920 target to whatever it feels convenient. If an explicit alignment is
921 specified, the function is forced to have at least that much alignment. All
922 alignments must be a power of 2.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]923
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]924<h5>Syntax:</h5>
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]925<pre class="doc_code">
Chris Lattner0ae02092008-10-13 16:55:18 +0000[diff] [blame]926define [<a href="#linkage">linkage</a>] [<a href="#visibility">visibility</a>]
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]927 [<a href="#callingconv">cconv</a>] [<a href="#paramattrs">ret attrs</a>]
928 &lt;ResultType&gt; @&lt;FunctionName&gt; ([argument list])
929 [<a href="#fnattrs">fn Attrs</a>] [section "name"] [align N]
930 [<a href="#gc">gc</a>] { ... }
931</pre>
Devang Patel02256232008-10-07 17:48:33 +0000[diff] [blame]932
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]933</div>
934
Anton Korobeynikova97b6942007-04-25 14:27:10 +0000[diff] [blame]935<!-- ======================================================================= -->
936<div class="doc_subsection">
937 <a name="aliasstructure">Aliases</a>
938</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]939
Anton Korobeynikova97b6942007-04-25 14:27:10 +0000[diff] [blame]940<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]941
942<p>Aliases act as "second name" for the aliasee value (which can be either
943 function, global variable, another alias or bitcast of global value). Aliases
944 may have an optional <a href="#linkage">linkage type</a>, and an
945 optional <a href="#visibility">visibility style</a>.</p>
Anton Korobeynikova97b6942007-04-25 14:27:10 +0000[diff] [blame]946
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]947<h5>Syntax:</h5>
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]948<pre class="doc_code">
Duncan Sands7e99a942008-09-12 20:48:21 +0000[diff] [blame]949@&lt;Name&gt; = alias [Linkage] [Visibility] &lt;AliaseeTy&gt; @&lt;Aliasee&gt;
Bill Wendling2d8b9a82007-05-29 09:42:13 +0000[diff] [blame]950</pre>
Anton Korobeynikova97b6942007-04-25 14:27:10 +0000[diff] [blame]951
952</div>
953
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]954<!-- ======================================================================= -->
Devang Pateld1a89692010-01-11 19:35:55 +0000[diff] [blame]955<div class="doc_subsection">
956 <a name="namedmetadatastructure">Named Metadata</a>
957</div>
958
959<div class="doc_text">
960
Chris Lattnerc2f8f162010-01-15 21:50:19 +0000[diff] [blame]961<p>Named metadata is a collection of metadata. <a href="#metadata">Metadata
Dan Gohman093cb792010-07-21 18:54:18 +0000[diff] [blame]962 nodes</a> (but not metadata strings) are the only valid operands for
Chris Lattnerc2f8f162010-01-15 21:50:19 +0000[diff] [blame]963 a named metadata.</p>
Devang Pateld1a89692010-01-11 19:35:55 +0000[diff] [blame]964
965<h5>Syntax:</h5>
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]966<pre class="doc_code">
Dan Gohman093cb792010-07-21 18:54:18 +0000[diff] [blame]967; Some unnamed metadata nodes, which are referenced by the named metadata.
968!0 = metadata !{metadata !"zero"}
Devang Pateld1a89692010-01-11 19:35:55 +0000[diff] [blame]969!1 = metadata !{metadata !"one"}
Dan Gohman093cb792010-07-21 18:54:18 +0000[diff] [blame]970!2 = metadata !{metadata !"two"}
Dan Gohman58cd65f2010-07-13 19:48:13 +0000[diff] [blame]971; A named metadata.
Dan Gohman093cb792010-07-21 18:54:18 +0000[diff] [blame]972!name = !{!0, !1, !2}
Devang Pateld1a89692010-01-11 19:35:55 +0000[diff] [blame]973</pre>
Devang Pateld1a89692010-01-11 19:35:55 +0000[diff] [blame]974
975</div>
976
977<!-- ======================================================================= -->
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]978<div class="doc_subsection"><a name="paramattrs">Parameter Attributes</a></div>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]979
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]980<div class="doc_text">
981
982<p>The return type and each parameter of a function type may have a set of
983 <i>parameter attributes</i> associated with them. Parameter attributes are
984 used to communicate additional information about the result or parameters of
985 a function. Parameter attributes are considered to be part of the function,
986 not of the function type, so functions with different parameter attributes
987 can have the same function type.</p>
988
989<p>Parameter attributes are simple keywords that follow the type specified. If
990 multiple parameter attributes are needed, they are space separated. For
991 example:</p>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]992
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]993<pre class="doc_code">
Nick Lewyckydac78d82009-02-15 23:06:14 +0000[diff] [blame]994declare i32 @printf(i8* noalias nocapture, ...)
Chris Lattnerd2597d72008-10-04 18:33:34 +0000[diff] [blame]995declare i32 @atoi(i8 zeroext)
996declare signext i8 @returns_signed_char()
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]997</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]998
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]999<p>Note that any attributes for the function result (<tt>nounwind</tt>,
1000 <tt>readonly</tt>) come immediately after the argument list.</p>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1001
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1002<p>Currently, only the following parameter attributes are defined:</p>
Chris Lattner5cee13f2008-01-11 06:20:47 +0000[diff] [blame]1003
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1004<dl>
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1005 <dt><tt><b>zeroext</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1006 <dd>This indicates to the code generator that the parameter or return value
1007 should be zero-extended to a 32-bit value by the caller (for a parameter)
1008 or the callee (for a return value).</dd>
Chris Lattner5cee13f2008-01-11 06:20:47 +0000[diff] [blame]1009
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1010 <dt><tt><b>signext</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1011 <dd>This indicates to the code generator that the parameter or return value
1012 should be sign-extended to a 32-bit value by the caller (for a parameter)
1013 or the callee (for a return value).</dd>
Chris Lattner5cee13f2008-01-11 06:20:47 +0000[diff] [blame]1014
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1015 <dt><tt><b>inreg</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1016 <dd>This indicates that this parameter or return value should be treated in a
1017 special target-dependent fashion during while emitting code for a function
1018 call or return (usually, by putting it in a register as opposed to memory,
1019 though some targets use it to distinguish between two different kinds of
1020 registers). Use of this attribute is target-specific.</dd>
Chris Lattner5cee13f2008-01-11 06:20:47 +0000[diff] [blame]1021
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1022 <dt><tt><b><a name="byval">byval</a></b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1023 <dd>This indicates that the pointer parameter should really be passed by value
1024 to the function. The attribute implies that a hidden copy of the pointee
1025 is made between the caller and the callee, so the callee is unable to
1026 modify the value in the callee. This attribute is only valid on LLVM
1027 pointer arguments. It is generally used to pass structs and arrays by
1028 value, but is also valid on pointers to scalars. The copy is considered
1029 to belong to the caller not the callee (for example,
1030 <tt><a href="#readonly">readonly</a></tt> functions should not write to
1031 <tt>byval</tt> parameters). This is not a valid attribute for return
1032 values. The byval attribute also supports specifying an alignment with
1033 the align attribute. This has a target-specific effect on the code
1034 generator that usually indicates a desired alignment for the synthesized
1035 stack slot.</dd>
1036
Dan Gohman3770af52010-07-02 23:18:08 +0000[diff] [blame]1037 <dt><tt><b><a name="sret">sret</a></b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1038 <dd>This indicates that the pointer parameter specifies the address of a
1039 structure that is the return value of the function in the source program.
1040 This pointer must be guaranteed by the caller to be valid: loads and
1041 stores to the structure may be assumed by the callee to not to trap. This
1042 may only be applied to the first parameter. This is not a valid attribute
1043 for return values. </dd>
1044
Dan Gohman3770af52010-07-02 23:18:08 +0000[diff] [blame]1045 <dt><tt><b><a name="noalias">noalias</a></b></tt></dt>
Dan Gohmandf12d082010-07-02 18:41:32 +0000[diff] [blame]1046 <dd>This indicates that pointer values
1047 <a href="#pointeraliasing"><i>based</i></a> on the argument or return
Dan Gohmande256292010-07-02 23:46:54 +0000[diff] [blame]1048 value do not alias pointer values which are not <i>based</i> on it,
1049 ignoring certain "irrelevant" dependencies.
1050 For a call to the parent function, dependencies between memory
1051 references from before or after the call and from those during the call
1052 are "irrelevant" to the <tt>noalias</tt> keyword for the arguments and
1053 return value used in that call.
Dan Gohmandf12d082010-07-02 18:41:32 +0000[diff] [blame]1054 The caller shares the responsibility with the callee for ensuring that
1055 these requirements are met.
1056 For further details, please see the discussion of the NoAlias response in
Dan Gohman6c858db2010-07-06 15:26:33 +0000[diff] [blame]1057 <a href="AliasAnalysis.html#MustMayNo">alias analysis</a>.<br>
1058<br>
John McCall72ed8902010-07-06 21:07:14 +0000[diff] [blame]1059 Note that this definition of <tt>noalias</tt> is intentionally
1060 similar to the definition of <tt>restrict</tt> in C99 for function
Chris Lattner5eff9ca2010-07-06 20:51:35 +0000[diff] [blame]1061 arguments, though it is slightly weaker.
Dan Gohman6c858db2010-07-06 15:26:33 +0000[diff] [blame]1062<br>
1063 For function return values, C99's <tt>restrict</tt> is not meaningful,
1064 while LLVM's <tt>noalias</tt> is.
1065 </dd>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1066
Dan Gohman3770af52010-07-02 23:18:08 +0000[diff] [blame]1067 <dt><tt><b><a name="nocapture">nocapture</a></b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1068 <dd>This indicates that the callee does not make any copies of the pointer
1069 that outlive the callee itself. This is not a valid attribute for return
1070 values.</dd>
1071
Dan Gohman3770af52010-07-02 23:18:08 +0000[diff] [blame]1072 <dt><tt><b><a name="nest">nest</a></b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1073 <dd>This indicates that the pointer parameter can be excised using the
1074 <a href="#int_trampoline">trampoline intrinsics</a>. This is not a valid
1075 attribute for return values.</dd>
1076</dl>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1077
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1078</div>
1079
1080<!-- ======================================================================= -->
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]1081<div class="doc_subsection">
Gordon Henriksen71183b62007-12-10 03:18:06 +0000[diff] [blame]1082 <a name="gc">Garbage Collector Names</a>
1083</div>
1084
1085<div class="doc_text">
Gordon Henriksen71183b62007-12-10 03:18:06 +0000[diff] [blame]1086
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1087<p>Each function may specify a garbage collector name, which is simply a
1088 string:</p>
1089
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]1090<pre class="doc_code">
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1091define void @f() gc "name" { ... }
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1092</pre>
Gordon Henriksen71183b62007-12-10 03:18:06 +0000[diff] [blame]1093
1094<p>The compiler declares the supported values of <i>name</i>. Specifying a
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1095 collector which will cause the compiler to alter its output in order to
1096 support the named garbage collection algorithm.</p>
1097
Gordon Henriksen71183b62007-12-10 03:18:06 +0000[diff] [blame]1098</div>
1099
1100<!-- ======================================================================= -->
1101<div class="doc_subsection">
Devang Patel9eb525d2008-09-26 23:51:19 +0000[diff] [blame]1102 <a name="fnattrs">Function Attributes</a>
Devang Patelcaacdba2008-09-04 23:05:13 +0000[diff] [blame]1103</div>
1104
1105<div class="doc_text">
Devang Patel9eb525d2008-09-26 23:51:19 +0000[diff] [blame]1106
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1107<p>Function attributes are set to communicate additional information about a
1108 function. Function attributes are considered to be part of the function, not
1109 of the function type, so functions with different parameter attributes can
1110 have the same function type.</p>
Devang Patel9eb525d2008-09-26 23:51:19 +0000[diff] [blame]1111
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1112<p>Function attributes are simple keywords that follow the type specified. If
1113 multiple attributes are needed, they are space separated. For example:</p>
Devang Patelcaacdba2008-09-04 23:05:13 +0000[diff] [blame]1114
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]1115<pre class="doc_code">
Devang Patel9eb525d2008-09-26 23:51:19 +0000[diff] [blame]1116define void @f() noinline { ... }
1117define void @f() alwaysinline { ... }
1118define void @f() alwaysinline optsize { ... }
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1119define void @f() optsize { ... }
Bill Wendlingb175fa42008-09-07 10:26:33 +0000[diff] [blame]1120</pre>
Devang Patelcaacdba2008-09-04 23:05:13 +0000[diff] [blame]1121
Bill Wendlingb175fa42008-09-07 10:26:33 +0000[diff] [blame]1122<dl>
Charles Davisbe5557e2010-02-12 00:31:15 +0000[diff] [blame]1123 <dt><tt><b>alignstack(&lt;<em>n</em>&gt;)</b></tt></dt>
1124 <dd>This attribute indicates that, when emitting the prologue and epilogue,
1125 the backend should forcibly align the stack pointer. Specify the
1126 desired alignment, which must be a power of two, in parentheses.
1127
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1128 <dt><tt><b>alwaysinline</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1129 <dd>This attribute indicates that the inliner should attempt to inline this
1130 function into callers whenever possible, ignoring any active inlining size
1131 threshold for this caller.</dd>
Bill Wendlingb175fa42008-09-07 10:26:33 +0000[diff] [blame]1132
Jakob Stoklund Olesen74bb06c2010-02-06 01:16:28 +0000[diff] [blame]1133 <dt><tt><b>inlinehint</b></tt></dt>
1134 <dd>This attribute indicates that the source code contained a hint that inlining
1135 this function is desirable (such as the "inline" keyword in C/C++). It
1136 is just a hint; it imposes no requirements on the inliner.</dd>
1137
Nick Lewycky14b58da2010-07-06 18:24:09 +0000[diff] [blame]1138 <dt><tt><b>naked</b></tt></dt>
1139 <dd>This attribute disables prologue / epilogue emission for the function.
1140 This can have very system-specific consequences.</dd>
1141
1142 <dt><tt><b>noimplicitfloat</b></tt></dt>
1143 <dd>This attributes disables implicit floating point instructions.</dd>
1144
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1145 <dt><tt><b>noinline</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1146 <dd>This attribute indicates that the inliner should never inline this
1147 function in any situation. This attribute may not be used together with
1148 the <tt>alwaysinline</tt> attribute.</dd>
Devang Patel9eb525d2008-09-26 23:51:19 +0000[diff] [blame]1149
Nick Lewycky14b58da2010-07-06 18:24:09 +0000[diff] [blame]1150 <dt><tt><b>noredzone</b></tt></dt>
1151 <dd>This attribute indicates that the code generator should not use a red
1152 zone, even if the target-specific ABI normally permits it.</dd>
Devang Patel9eb525d2008-09-26 23:51:19 +0000[diff] [blame]1153
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1154 <dt><tt><b>noreturn</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1155 <dd>This function attribute indicates that the function never returns
1156 normally. This produces undefined behavior at runtime if the function
1157 ever does dynamically return.</dd>
Bill Wendlinga8130172008-11-13 01:02:51 +0000[diff] [blame]1158
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1159 <dt><tt><b>nounwind</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1160 <dd>This function attribute indicates that the function never returns with an
1161 unwind or exceptional control flow. If the function does unwind, its
1162 runtime behavior is undefined.</dd>
Bill Wendling0f5541e2008-11-26 19:07:40 +0000[diff] [blame]1163
Nick Lewycky14b58da2010-07-06 18:24:09 +0000[diff] [blame]1164 <dt><tt><b>optsize</b></tt></dt>
1165 <dd>This attribute suggests that optimization passes and code generator passes
1166 make choices that keep the code size of this function low, and otherwise
1167 do optimizations specifically to reduce code size.</dd>
1168
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1169 <dt><tt><b>readnone</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1170 <dd>This attribute indicates that the function computes its result (or decides
1171 to unwind an exception) based strictly on its arguments, without
1172 dereferencing any pointer arguments or otherwise accessing any mutable
1173 state (e.g. memory, control registers, etc) visible to caller functions.
1174 It does not write through any pointer arguments
1175 (including <tt><a href="#byval">byval</a></tt> arguments) and never
1176 changes any state visible to callers. This means that it cannot unwind
1177 exceptions by calling the <tt>C++</tt> exception throwing methods, but
1178 could use the <tt>unwind</tt> instruction.</dd>
Devang Patel310fd4a2009-06-12 19:45:19 +0000[diff] [blame]1179
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1180 <dt><tt><b><a name="readonly">readonly</a></b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1181 <dd>This attribute indicates that the function does not write through any
1182 pointer arguments (including <tt><a href="#byval">byval</a></tt>
1183 arguments) or otherwise modify any state (e.g. memory, control registers,
1184 etc) visible to caller functions. It may dereference pointer arguments
1185 and read state that may be set in the caller. A readonly function always
1186 returns the same value (or unwinds an exception identically) when called
1187 with the same set of arguments and global state. It cannot unwind an
1188 exception by calling the <tt>C++</tt> exception throwing methods, but may
1189 use the <tt>unwind</tt> instruction.</dd>
Anton Korobeynikovc8ce7b082009-07-17 18:07:26 +0000[diff] [blame]1190
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1191 <dt><tt><b><a name="ssp">ssp</a></b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1192 <dd>This attribute indicates that the function should emit a stack smashing
1193 protector. It is in the form of a "canary"&mdash;a random value placed on
1194 the stack before the local variables that's checked upon return from the
1195 function to see if it has been overwritten. A heuristic is used to
1196 determine if a function needs stack protectors or not.<br>
1197<br>
1198 If a function that has an <tt>ssp</tt> attribute is inlined into a
1199 function that doesn't have an <tt>ssp</tt> attribute, then the resulting
1200 function will have an <tt>ssp</tt> attribute.</dd>
1201
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1202 <dt><tt><b>sspreq</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1203 <dd>This attribute indicates that the function should <em>always</em> emit a
1204 stack smashing protector. This overrides
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1205 the <tt><a href="#ssp">ssp</a></tt> function attribute.<br>
1206<br>
1207 If a function that has an <tt>sspreq</tt> attribute is inlined into a
1208 function that doesn't have an <tt>sspreq</tt> attribute or which has
1209 an <tt>ssp</tt> attribute, then the resulting function will have
1210 an <tt>sspreq</tt> attribute.</dd>
Bill Wendlingb175fa42008-09-07 10:26:33 +0000[diff] [blame]1211</dl>
1212
Devang Patelcaacdba2008-09-04 23:05:13 +0000[diff] [blame]1213</div>
1214
1215<!-- ======================================================================= -->
1216<div class="doc_subsection">
Chris Lattner93564892006-04-08 04:40:53 +0000[diff] [blame]1217 <a name="moduleasm">Module-Level Inline Assembly</a>
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]1218</div>
1219
1220<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1221
1222<p>Modules may contain "module-level inline asm" blocks, which corresponds to
1223 the GCC "file scope inline asm" blocks. These blocks are internally
1224 concatenated by LLVM and treated as a single unit, but may be separated in
1225 the <tt>.ll</tt> file if desired. The syntax is very simple:</p>
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]1226
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]1227<pre class="doc_code">
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]1228module asm "inline asm code goes here"
1229module asm "more can go here"
1230</pre>
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]1231
1232<p>The strings can contain any character by escaping non-printable characters.
1233 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]1234 for the number.</p>
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]1235
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1236<p>The inline asm code is simply printed to the machine code .s file when
1237 assembly code is generated.</p>
1238
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]1239</div>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]1240
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1241<!-- ======================================================================= -->
1242<div class="doc_subsection">
1243 <a name="datalayout">Data Layout</a>
1244</div>
1245
1246<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1247
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1248<p>A module may specify a target specific data layout string that specifies how
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1249 data is to be laid out in memory. The syntax for the data layout is
1250 simply:</p>
1251
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]1252<pre class="doc_code">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1253target datalayout = "<i>layout specification</i>"
1254</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1255
1256<p>The <i>layout specification</i> consists of a list of specifications
1257 separated by the minus sign character ('-'). Each specification starts with
1258 a letter and may include other information after the letter to define some
1259 aspect of the data layout. The specifications accepted are as follows:</p>
1260
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1261<dl>
1262 <dt><tt>E</tt></dt>
1263 <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]1264 bits with the most significance have the lowest address location.</dd>
1265
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1266 <dt><tt>e</tt></dt>
Chris Lattner67c37d12008-08-05 18:29:16 +0000[diff] [blame]1267 <dd>Specifies that the target lays out data in little-endian form. That is,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1268 the bits with the least significance have the lowest address
1269 location.</dd>
1270
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1271 <dt><tt>p:<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]1272 <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]1273 <i>preferred</i> alignments. All sizes are in bits. Specifying
1274 the <i>pref</i> alignment is optional. If omitted, the
1275 preceding <tt>:</tt> should be omitted too.</dd>
1276
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1277 <dt><tt>i<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1278 <dd>This specifies the alignment for an integer type of a given bit
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1279 <i>size</i>. The value of <i>size</i> must be in the range [1,2^23).</dd>
1280
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1281 <dt><tt>v<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]1282 <dd>This specifies the alignment for a vector type of a given bit
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1283 <i>size</i>.</dd>
1284
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1285 <dt><tt>f<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]1286 <dd>This specifies the alignment for a floating point type of a given bit
Dale Johannesence522852010-05-28 18:54:47 +0000[diff] [blame]1287 <i>size</i>. Only values of <i>size</i> that are supported by the target
1288 will work. 32 (float) and 64 (double) are supported on all targets;
1289 80 or 128 (different flavors of long double) are also supported on some
1290 targets.
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1291
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1292 <dt><tt>a<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1293 <dd>This specifies the alignment for an aggregate type of a given bit
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1294 <i>size</i>.</dd>
1295
Daniel Dunbar7921a592009-06-08 22:17:53 +0000[diff] [blame]1296 <dt><tt>s<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1297 <dd>This specifies the alignment for a stack object of a given bit
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1298 <i>size</i>.</dd>
Chris Lattnera381eff2009-11-07 09:35:34 +0000[diff] [blame]1299
1300 <dt><tt>n<i>size1</i>:<i>size2</i>:<i>size3</i>...</tt></dt>
1301 <dd>This specifies a set of native integer widths for the target CPU
1302 in bits. For example, it might contain "n32" for 32-bit PowerPC,
1303 "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]1304 this set are considered to support most general arithmetic
Chris Lattnera381eff2009-11-07 09:35:34 +0000[diff] [blame]1305 operations efficiently.</dd>
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1306</dl>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1307
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1308<p>When constructing the data layout for a given target, LLVM starts with a
Dan Gohman61110ae2010-04-28 00:36:01 +0000[diff] [blame]1309 default set of specifications which are then (possibly) overridden by the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1310 specifications in the <tt>datalayout</tt> keyword. The default specifications
1311 are given in this list:</p>
1312
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1313<ul>
1314 <li><tt>E</tt> - big endian</li>
Dan Gohman8ad777d2010-02-23 02:44:03 +0000[diff] [blame]1315 <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]1316 <li><tt>i1:8:8</tt> - i1 is 8-bit (byte) aligned</li>
1317 <li><tt>i8:8:8</tt> - i8 is 8-bit (byte) aligned</li>
1318 <li><tt>i16:16:16</tt> - i16 is 16-bit aligned</li>
1319 <li><tt>i32:32:32</tt> - i32 is 32-bit aligned</li>
Chris Lattner67c37d12008-08-05 18:29:16 +0000[diff] [blame]1320 <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]1321 alignment of 64-bits</li>
1322 <li><tt>f32:32:32</tt> - float is 32-bit aligned</li>
1323 <li><tt>f64:64:64</tt> - double is 64-bit aligned</li>
1324 <li><tt>v64:64:64</tt> - 64-bit vector is 64-bit aligned</li>
1325 <li><tt>v128:128:128</tt> - 128-bit vector is 128-bit aligned</li>
1326 <li><tt>a0:0:1</tt> - aggregates are 8-bit aligned</li>
Daniel Dunbar7921a592009-06-08 22:17:53 +0000[diff] [blame]1327 <li><tt>s0:64:64</tt> - stack objects are 64-bit aligned</li>
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1328</ul>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1329
1330<p>When LLVM is determining the alignment for a given type, it uses the
1331 following rules:</p>
1332
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1333<ol>
1334 <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]1335 specification is used.</li>
1336
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1337 <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]1338 smallest integer type that is larger than the bitwidth of the sought type
1339 is used. If none of the specifications are larger than the bitwidth then
1340 the the largest integer type is used. For example, given the default
1341 specifications above, the i7 type will use the alignment of i8 (next
1342 largest) while both i65 and i256 will use the alignment of i64 (largest
1343 specified).</li>
1344
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1345 <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]1346 largest vector type that is smaller than the sought vector type will be
1347 used as a fall back. This happens because &lt;128 x double&gt; can be
1348 implemented in terms of 64 &lt;2 x double&gt;, for example.</li>
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1349</ol>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1350
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1351</div>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]1352
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1353<!-- ======================================================================= -->
1354<div class="doc_subsection">
1355 <a name="pointeraliasing">Pointer Aliasing Rules</a>
1356</div>
1357
1358<div class="doc_text">
1359
Andreas Bolka8ae4e242009-07-29 00:02:05 +0000[diff] [blame]1360<p>Any memory access must be done through a pointer value associated
Andreas Bolkae39f0332009-07-27 20:37:10 +0000[diff] [blame]1361with an address range of the memory access, otherwise the behavior
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1362is undefined. Pointer values are associated with address ranges
1363according to the following rules:</p>
1364
1365<ul>
Dan Gohmandf12d082010-07-02 18:41:32 +0000[diff] [blame]1366 <li>A pointer value is associated with the addresses associated with
1367 any value it is <i>based</i> on.
Andreas Bolka8ae4e242009-07-29 00:02:05 +0000[diff] [blame]1368 <li>An address of a global variable is associated with the address
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1369 range of the variable's storage.</li>
1370 <li>The result value of an allocation instruction is associated with
1371 the address range of the allocated storage.</li>
1372 <li>A null pointer in the default address-space is associated with
Andreas Bolka8ae4e242009-07-29 00:02:05 +0000[diff] [blame]1373 no address.</li>
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1374 <li>An integer constant other than zero or a pointer value returned
1375 from a function not defined within LLVM may be associated with address
1376 ranges allocated through mechanisms other than those provided by
Andreas Bolka8ae4e242009-07-29 00:02:05 +0000[diff] [blame]1377 LLVM. Such ranges shall not overlap with any ranges of addresses
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1378 allocated by mechanisms provided by LLVM.</li>
Dan Gohmandf12d082010-07-02 18:41:32 +0000[diff] [blame]1379</ul>
1380
1381<p>A pointer value is <i>based</i> on another pointer value according
1382 to the following rules:</p>
1383
1384<ul>
1385 <li>A pointer value formed from a
1386 <tt><a href="#i_getelementptr">getelementptr</a></tt> operation
1387 is <i>based</i> on the first operand of the <tt>getelementptr</tt>.</li>
1388 <li>The result value of a
1389 <tt><a href="#i_bitcast">bitcast</a></tt> is <i>based</i> on the operand
1390 of the <tt>bitcast</tt>.</li>
1391 <li>A pointer value formed by an
1392 <tt><a href="#i_inttoptr">inttoptr</a></tt> is <i>based</i> on all
1393 pointer values that contribute (directly or indirectly) to the
1394 computation of the pointer's value.</li>
1395 <li>The "<i>based</i> on" relationship is transitive.</li>
1396</ul>
1397
1398<p>Note that this definition of <i>"based"</i> is intentionally
1399 similar to the definition of <i>"based"</i> in C99, though it is
1400 slightly weaker.</p>
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1401
1402<p>LLVM IR does not associate types with memory. The result type of a
Andreas Bolka8ae4e242009-07-29 00:02:05 +0000[diff] [blame]1403<tt><a href="#i_load">load</a></tt> merely indicates the size and
1404alignment of the memory from which to load, as well as the
Dan Gohman4eb47192010-06-17 19:23:50 +0000[diff] [blame]1405interpretation of the value. The first operand type of a
Andreas Bolka8ae4e242009-07-29 00:02:05 +0000[diff] [blame]1406<tt><a href="#i_store">store</a></tt> similarly only indicates the size
1407and alignment of the store.</p>
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1408
1409<p>Consequently, type-based alias analysis, aka TBAA, aka
1410<tt>-fstrict-aliasing</tt>, is not applicable to general unadorned
1411LLVM IR. <a href="#metadata">Metadata</a> may be used to encode
1412additional information which specialized optimization passes may use
1413to implement type-based alias analysis.</p>
1414
1415</div>
1416
Jeffrey Yasskin5d284ae2010-04-26 21:21:24 +0000[diff] [blame]1417<!-- ======================================================================= -->
1418<div class="doc_subsection">
1419 <a name="volatile">Volatile Memory Accesses</a>
1420</div>
1421
1422<div class="doc_text">
1423
1424<p>Certain memory accesses, such as <a href="#i_load"><tt>load</tt></a>s, <a
1425href="#i_store"><tt>store</tt></a>s, and <a
1426href="#int_memcpy"><tt>llvm.memcpy</tt></a>s may be marked <tt>volatile</tt>.
1427The optimizers must not change the number of volatile operations or change their
1428order of execution relative to other volatile operations. The optimizers
1429<i>may</i> change the order of volatile operations relative to non-volatile
1430operations. This is not Java's "volatile" and has no cross-thread
1431synchronization behavior.</p>
1432
1433</div>
1434
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1435<!-- *********************************************************************** -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1436<div class="doc_section"> <a name="typesystem">Type System</a> </div>
1437<!-- *********************************************************************** -->
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]1438
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1439<div class="doc_text">
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]1440
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1441<p>The LLVM type system is one of the most important features of the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1442 intermediate representation. Being typed enables a number of optimizations
1443 to be performed on the intermediate representation directly, without having
1444 to do extra analyses on the side before the transformation. A strong type
1445 system makes it easier to read the generated code and enables novel analyses
1446 and transformations that are not feasible to perform on normal three address
1447 code representations.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]1448
1449</div>
1450
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1451<!-- ======================================================================= -->
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1452<div class="doc_subsection"> <a name="t_classifications">Type
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1453Classifications</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1454
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1455<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1456
1457<p>The types fall into a few useful classifications:</p>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]1458
1459<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1460 <tbody>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1461 <tr><th>Classification</th><th>Types</th></tr>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1462 <tr>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1463 <td><a href="#t_integer">integer</a></td>
Reid Spencer138249b2007-05-16 18:44:01 +0000[diff] [blame]1464 <td><tt>i1, i2, i3, ... i8, ... i16, ... i32, ... i64, ... </tt></td>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1465 </tr>
1466 <tr>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1467 <td><a href="#t_floating">floating point</a></td>
1468 <td><tt>float, double, x86_fp80, fp128, ppc_fp128</tt></td>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1469 </tr>
1470 <tr>
1471 <td><a name="t_firstclass">first class</a></td>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1472 <td><a href="#t_integer">integer</a>,
1473 <a href="#t_floating">floating point</a>,
1474 <a href="#t_pointer">pointer</a>,
Dan Gohman08783a882008-06-18 18:42:13 +0000[diff] [blame]1475 <a href="#t_vector">vector</a>,
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]1476 <a href="#t_struct">structure</a>,
1477 <a href="#t_array">array</a>,
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1478 <a href="#t_label">label</a>,
1479 <a href="#t_metadata">metadata</a>.
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1480 </td>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1481 </tr>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1482 <tr>
1483 <td><a href="#t_primitive">primitive</a></td>
1484 <td><a href="#t_label">label</a>,
1485 <a href="#t_void">void</a>,
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1486 <a href="#t_floating">floating point</a>,
1487 <a href="#t_metadata">metadata</a>.</td>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1488 </tr>
1489 <tr>
1490 <td><a href="#t_derived">derived</a></td>
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]1491 <td><a href="#t_array">array</a>,
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1492 <a href="#t_function">function</a>,
1493 <a href="#t_pointer">pointer</a>,
1494 <a href="#t_struct">structure</a>,
1495 <a href="#t_pstruct">packed structure</a>,
1496 <a href="#t_vector">vector</a>,
1497 <a href="#t_opaque">opaque</a>.
Dan Gohman93bf60d2008-10-14 16:32:04 +0000[diff] [blame]1498 </td>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1499 </tr>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1500 </tbody>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1501</table>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]1502
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1503<p>The <a href="#t_firstclass">first class</a> types are perhaps the most
1504 important. Values of these types are the only ones which can be produced by
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]1505 instructions.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1506
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1507</div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1508
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1509<!-- ======================================================================= -->
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1510<div class="doc_subsection"> <a name="t_primitive">Primitive Types</a> </div>
Chris Lattner43542b32008-01-04 04:34:14 +0000[diff] [blame]1511
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1512<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1513
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1514<p>The primitive types are the fundamental building blocks of the LLVM
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1515 system.</p>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1516
Chris Lattner43542b32008-01-04 04:34:14 +0000[diff] [blame]1517</div>
1518
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1519<!-- _______________________________________________________________________ -->
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]1520<div class="doc_subsubsection"> <a name="t_integer">Integer Type</a> </div>
1521
1522<div class="doc_text">
1523
1524<h5>Overview:</h5>
1525<p>The integer type is a very simple type that simply specifies an arbitrary
1526 bit width for the integer type desired. Any bit width from 1 bit to
1527 2<sup>23</sup>-1 (about 8 million) can be specified.</p>
1528
1529<h5>Syntax:</h5>
1530<pre>
1531 iN
1532</pre>
1533
1534<p>The number of bits the integer will occupy is specified by the <tt>N</tt>
1535 value.</p>
1536
1537<h5>Examples:</h5>
1538<table class="layout">
1539 <tr class="layout">
1540 <td class="left"><tt>i1</tt></td>
1541 <td class="left">a single-bit integer.</td>
1542 </tr>
1543 <tr class="layout">
1544 <td class="left"><tt>i32</tt></td>
1545 <td class="left">a 32-bit integer.</td>
1546 </tr>
1547 <tr class="layout">
1548 <td class="left"><tt>i1942652</tt></td>
1549 <td class="left">a really big integer of over 1 million bits.</td>
1550 </tr>
1551</table>
1552
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]1553</div>
1554
1555<!-- _______________________________________________________________________ -->
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1556<div class="doc_subsubsection"> <a name="t_floating">Floating Point Types</a> </div>
1557
1558<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1559
1560<table>
1561 <tbody>
1562 <tr><th>Type</th><th>Description</th></tr>
1563 <tr><td><tt>float</tt></td><td>32-bit floating point value</td></tr>
1564 <tr><td><tt>double</tt></td><td>64-bit floating point value</td></tr>
1565 <tr><td><tt>fp128</tt></td><td>128-bit floating point value (112-bit mantissa)</td></tr>
1566 <tr><td><tt>x86_fp80</tt></td><td>80-bit floating point value (X87)</td></tr>
1567 <tr><td><tt>ppc_fp128</tt></td><td>128-bit floating point value (two 64-bits)</td></tr>
1568 </tbody>
1569</table>
1570
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1571</div>
1572
1573<!-- _______________________________________________________________________ -->
1574<div class="doc_subsubsection"> <a name="t_void">Void Type</a> </div>
1575
1576<div class="doc_text">
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1577
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1578<h5>Overview:</h5>
1579<p>The void type does not represent any value and has no size.</p>
1580
1581<h5>Syntax:</h5>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1582<pre>
1583 void
1584</pre>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1585
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1586</div>
1587
1588<!-- _______________________________________________________________________ -->
1589<div class="doc_subsubsection"> <a name="t_label">Label Type</a> </div>
1590
1591<div class="doc_text">
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1592
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1593<h5>Overview:</h5>
1594<p>The label type represents code labels.</p>
1595
1596<h5>Syntax:</h5>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1597<pre>
1598 label
1599</pre>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1600
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1601</div>
1602
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1603<!-- _______________________________________________________________________ -->
1604<div class="doc_subsubsection"> <a name="t_metadata">Metadata Type</a> </div>
1605
1606<div class="doc_text">
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1607
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1608<h5>Overview:</h5>
Nick Lewycky93e06a52009-09-27 23:27:42 +0000[diff] [blame]1609<p>The metadata type represents embedded metadata. No derived types may be
1610 created from metadata except for <a href="#t_function">function</a>
1611 arguments.
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1612
1613<h5>Syntax:</h5>
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1614<pre>
1615 metadata
1616</pre>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1617
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1618</div>
1619
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1620
1621<!-- ======================================================================= -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1622<div class="doc_subsection"> <a name="t_derived">Derived Types</a> </div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1623
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1624<div class="doc_text">
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1625
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1626<p>The real power in LLVM comes from the derived types in the system. This is
1627 what allows a programmer to represent arrays, functions, pointers, and other
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]1628 useful types. Each of these types contain one or more element types which
1629 may be a primitive type, or another derived type. For example, it is
1630 possible to have a two dimensional array, using an array as the element type
1631 of another array.</p>
Dan Gohman142ccc02009-01-24 15:58:40 +0000[diff] [blame]1632
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]1633
1634</div>
1635
1636<!-- _______________________________________________________________________ -->
1637<div class="doc_subsubsection"> <a name="t_aggregate">Aggregate Types</a> </div>
1638
1639<div class="doc_text">
1640
1641<p>Aggregate Types are a subset of derived types that can contain multiple
1642 member types. <a href="#t_array">Arrays</a>,
Chris Lattner13ee7952010-08-28 04:09:24 +0000[diff] [blame^]1643 <a href="#t_struct">structs</a>, and <a href="#t_vector">vectors</a> are
1644 aggregate types.</p>
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]1645
1646</div>
1647
Reid Spencer138249b2007-05-16 18:44:01 +0000[diff] [blame]1648<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1649<div class="doc_subsubsection"> <a name="t_array">Array Type</a> </div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1650
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1651<div class="doc_text">
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1652
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1653<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1654<p>The array type is a very simple derived type that arranges elements
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1655 sequentially in memory. The array type requires a size (number of elements)
1656 and an underlying data type.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1657
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]1658<h5>Syntax:</h5>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1659<pre>
1660 [&lt;# elements&gt; x &lt;elementtype&gt;]
1661</pre>
1662
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1663<p>The number of elements is a constant integer value; <tt>elementtype</tt> may
1664 be any type with a size.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1665
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]1666<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1667<table class="layout">
1668 <tr class="layout">
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]1669 <td class="left"><tt>[40 x i32]</tt></td>
1670 <td class="left">Array of 40 32-bit integer values.</td>
1671 </tr>
1672 <tr class="layout">
1673 <td class="left"><tt>[41 x i32]</tt></td>
1674 <td class="left">Array of 41 32-bit integer values.</td>
1675 </tr>
1676 <tr class="layout">
1677 <td class="left"><tt>[4 x i8]</tt></td>
1678 <td class="left">Array of 4 8-bit integer values.</td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1679 </tr>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1680</table>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1681<p>Here are some examples of multidimensional arrays:</p>
1682<table class="layout">
1683 <tr class="layout">
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]1684 <td class="left"><tt>[3 x [4 x i32]]</tt></td>
1685 <td class="left">3x4 array of 32-bit integer values.</td>
1686 </tr>
1687 <tr class="layout">
1688 <td class="left"><tt>[12 x [10 x float]]</tt></td>
1689 <td class="left">12x10 array of single precision floating point values.</td>
1690 </tr>
1691 <tr class="layout">
1692 <td class="left"><tt>[2 x [3 x [4 x i16]]]</tt></td>
1693 <td class="left">2x3x4 array of 16-bit integer values.</td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1694 </tr>
1695</table>
Chris Lattnerc0ad71e2005-06-24 17:22:57 +0000[diff] [blame]1696
Dan Gohmanc74bc282009-11-09 19:01:53 +0000[diff] [blame]1697<p>There is no restriction on indexing beyond the end of the array implied by
1698 a static type (though there are restrictions on indexing beyond the bounds
1699 of an allocated object in some cases). This means that single-dimension
1700 'variable sized array' addressing can be implemented in LLVM with a zero
1701 length array type. An implementation of 'pascal style arrays' in LLVM could
1702 use the type "<tt>{ i32, [0 x float]}</tt>", for example.</p>
Chris Lattnerc0ad71e2005-06-24 17:22:57 +0000[diff] [blame]1703
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1704</div>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1705
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1706<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1707<div class="doc_subsubsection"> <a name="t_function">Function Type</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1708
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1709<div class="doc_text">
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]1710
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1711<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1712<p>The function type can be thought of as a function signature. It consists of
1713 a return type and a list of formal parameter types. The return type of a
Chris Lattner13ee7952010-08-28 04:09:24 +0000[diff] [blame^]1714 function type is a first class type or a void type.</p>
Devang Pateld6cff512008-03-10 20:49:15 +0000[diff] [blame]1715
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1716<h5>Syntax:</h5>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]1717<pre>
Nick Lewycky14d1ccc2009-09-27 07:55:32 +0000[diff] [blame]1718 &lt;returntype&gt; (&lt;parameter list&gt;)
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]1719</pre>
1720
John Criswell4c0cf7f2005-10-24 16:17:18 +0000[diff] [blame]1721<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]1722 specifiers. Optionally, the parameter list may include a type <tt>...</tt>,
1723 which indicates that the function takes a variable number of arguments.
1724 Variable argument functions can access their arguments with
1725 the <a href="#int_varargs">variable argument handling intrinsic</a>
Chris Lattner47f2a832010-03-02 06:36:51 +0000[diff] [blame]1726 functions. '<tt>&lt;returntype&gt;</tt>' is any type except
Nick Lewycky93e06a52009-09-27 23:27:42 +0000[diff] [blame]1727 <a href="#t_label">label</a>.</p>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]1728
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1729<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1730<table class="layout">
1731 <tr class="layout">
Reid Spencer58c08712006-12-31 07:18:34 +0000[diff] [blame]1732 <td class="left"><tt>i32 (i32)</tt></td>
1733 <td class="left">function taking an <tt>i32</tt>, returning an <tt>i32</tt>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1734 </td>
Reid Spencer58c08712006-12-31 07:18:34 +0000[diff] [blame]1735 </tr><tr class="layout">
Chris Lattner47f2a832010-03-02 06:36:51 +0000[diff] [blame]1736 <td class="left"><tt>float&nbsp;(i16,&nbsp;i32&nbsp;*)&nbsp;*
Reid Spencer655dcc62006-12-31 07:20:23 +0000[diff] [blame]1737 </tt></td>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]1738 <td class="left"><a href="#t_pointer">Pointer</a> to a function that takes
Chris Lattner47f2a832010-03-02 06:36:51 +0000[diff] [blame]1739 an <tt>i16</tt> and a <a href="#t_pointer">pointer</a> to <tt>i32</tt>,
1740 returning <tt>float</tt>.
Reid Spencer58c08712006-12-31 07:18:34 +0000[diff] [blame]1741 </td>
1742 </tr><tr class="layout">
1743 <td class="left"><tt>i32 (i8*, ...)</tt></td>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]1744 <td class="left">A vararg function that takes at least one
1745 <a href="#t_pointer">pointer</a> to <tt>i8 </tt> (char in C),
1746 which returns an integer. This is the signature for <tt>printf</tt> in
Reid Spencer58c08712006-12-31 07:18:34 +0000[diff] [blame]1747 LLVM.
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1748 </td>
Devang Patele3dfc1c2008-03-24 05:35:41 +0000[diff] [blame]1749 </tr><tr class="layout">
1750 <td class="left"><tt>{i32, i32} (i32)</tt></td>
Nick Lewycky14d1ccc2009-09-27 07:55:32 +0000[diff] [blame]1751 <td class="left">A function taking an <tt>i32</tt>, returning a
1752 <a href="#t_struct">structure</a> containing two <tt>i32</tt> values
Devang Patele3dfc1c2008-03-24 05:35:41 +0000[diff] [blame]1753 </td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1754 </tr>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1755</table>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]1756
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1757</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1758
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1759<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1760<div class="doc_subsubsection"> <a name="t_struct">Structure Type</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1761
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1762<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1763
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1764<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1765<p>The structure type is used to represent a collection of data members together
1766 in memory. The packing of the field types is defined to match the ABI of the
1767 underlying processor. The elements of a structure may be any type that has a
1768 size.</p>
1769
Jeffrey Yasskinf991bbb2010-01-11 19:19:26 +0000[diff] [blame]1770<p>Structures in memory are accessed using '<tt><a href="#i_load">load</a></tt>'
1771 and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a field
1772 with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.
1773 Structures in registers are accessed using the
1774 '<tt><a href="#i_extractvalue">extractvalue</a></tt>' and
1775 '<tt><a href="#i_insertvalue">insertvalue</a></tt>' instructions.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1776<h5>Syntax:</h5>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1777<pre>
1778 { &lt;type list&gt; }
1779</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1780
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1781<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1782<table class="layout">
1783 <tr class="layout">
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]1784 <td class="left"><tt>{ i32, i32, i32 }</tt></td>
1785 <td class="left">A triple of three <tt>i32</tt> values</td>
1786 </tr><tr class="layout">
1787 <td class="left"><tt>{&nbsp;float,&nbsp;i32&nbsp;(i32)&nbsp;*&nbsp;}</tt></td>
1788 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1789 second element is a <a href="#t_pointer">pointer</a> to a
1790 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1791 an <tt>i32</tt>.</td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1792 </tr>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1793</table>
Dan Gohman142ccc02009-01-24 15:58:40 +0000[diff] [blame]1794
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1795</div>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1796
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1797<!-- _______________________________________________________________________ -->
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]1798<div class="doc_subsubsection"> <a name="t_pstruct">Packed Structure Type</a>
1799</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1800
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]1801<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1802
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]1803<h5>Overview:</h5>
1804<p>The packed structure type is used to represent a collection of data members
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1805 together in memory. There is no padding between fields. Further, the
1806 alignment of a packed structure is 1 byte. The elements of a packed
1807 structure may be any type that has a size.</p>
1808
1809<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt> and
1810 '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a field with
1811 the '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
1812
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]1813<h5>Syntax:</h5>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1814<pre>
1815 &lt; { &lt;type list&gt; } &gt;
1816</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1817
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]1818<h5>Examples:</h5>
1819<table class="layout">
1820 <tr class="layout">
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]1821 <td class="left"><tt>&lt; { i32, i32, i32 } &gt;</tt></td>
1822 <td class="left">A triple of three <tt>i32</tt> values</td>
1823 </tr><tr class="layout">
Bill Wendlingb175fa42008-09-07 10:26:33 +0000[diff] [blame]1824 <td class="left">
1825<tt>&lt;&nbsp;{&nbsp;float,&nbsp;i32&nbsp;(i32)*&nbsp;}&nbsp;&gt;</tt></td>
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]1826 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1827 second element is a <a href="#t_pointer">pointer</a> to a
1828 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1829 an <tt>i32</tt>.</td>
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]1830 </tr>
1831</table>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1832
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]1833</div>
1834
1835<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1836<div class="doc_subsubsection"> <a name="t_pointer">Pointer Type</a> </div>
Chris Lattner4a67c912009-02-08 19:53:29 +0000[diff] [blame]1837
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1838<div class="doc_text">
1839
1840<h5>Overview:</h5>
Dan Gohman88481112010-02-25 16:50:07 +0000[diff] [blame]1841<p>The pointer type is used to specify memory locations.
1842 Pointers are commonly used to reference objects in memory.</p>
1843
1844<p>Pointer types may have an optional address space attribute defining the
1845 numbered address space where the pointed-to object resides. The default
1846 address space is number zero. The semantics of non-zero address
1847 spaces are target-specific.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1848
1849<p>Note that LLVM does not permit pointers to void (<tt>void*</tt>) nor does it
1850 permit pointers to labels (<tt>label*</tt>). Use <tt>i8*</tt> instead.</p>
Chris Lattner4a67c912009-02-08 19:53:29 +0000[diff] [blame]1851
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]1852<h5>Syntax:</h5>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1853<pre>
1854 &lt;type&gt; *
1855</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1856
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]1857<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1858<table class="layout">
1859 <tr class="layout">
Dan Gohman623806e2009-01-04 23:44:43 +0000[diff] [blame]1860 <td class="left"><tt>[4 x i32]*</tt></td>
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]1861 <td class="left">A <a href="#t_pointer">pointer</a> to <a
1862 href="#t_array">array</a> of four <tt>i32</tt> values.</td>
1863 </tr>
1864 <tr class="layout">
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]1865 <td class="left"><tt>i32 (i32*) *</tt></td>
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]1866 <td class="left"> A <a href="#t_pointer">pointer</a> to a <a
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1867 href="#t_function">function</a> that takes an <tt>i32*</tt>, returning an
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]1868 <tt>i32</tt>.</td>
1869 </tr>
1870 <tr class="layout">
1871 <td class="left"><tt>i32 addrspace(5)*</tt></td>
1872 <td class="left">A <a href="#t_pointer">pointer</a> to an <tt>i32</tt> value
1873 that resides in address space #5.</td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1874 </tr>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1875</table>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1876
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1877</div>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1878
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1879<!-- _______________________________________________________________________ -->
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]1880<div class="doc_subsubsection"> <a name="t_vector">Vector Type</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1881
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1882<div class="doc_text">
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1883
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1884<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1885<p>A vector type is a simple derived type that represents a vector of elements.
1886 Vector types are used when multiple primitive data are operated in parallel
1887 using a single instruction (SIMD). A vector type requires a size (number of
Duncan Sands31c0e0e2009-11-27 13:38:03 +0000[diff] [blame]1888 elements) and an underlying primitive data type. Vector types are considered
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1889 <a href="#t_firstclass">first class</a>.</p>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1890
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1891<h5>Syntax:</h5>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1892<pre>
1893 &lt; &lt;# elements&gt; x &lt;elementtype&gt; &gt;
1894</pre>
1895
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1896<p>The number of elements is a constant integer value; elementtype may be any
1897 integer or floating point type.</p>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1898
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1899<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1900<table class="layout">
1901 <tr class="layout">
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]1902 <td class="left"><tt>&lt;4 x i32&gt;</tt></td>
1903 <td class="left">Vector of 4 32-bit integer values.</td>
1904 </tr>
1905 <tr class="layout">
1906 <td class="left"><tt>&lt;8 x float&gt;</tt></td>
1907 <td class="left">Vector of 8 32-bit floating-point values.</td>
1908 </tr>
1909 <tr class="layout">
1910 <td class="left"><tt>&lt;2 x i64&gt;</tt></td>
1911 <td class="left">Vector of 2 64-bit integer values.</td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1912 </tr>
1913</table>
Dan Gohman142ccc02009-01-24 15:58:40 +0000[diff] [blame]1914
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1915</div>
1916
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1917<!-- _______________________________________________________________________ -->
1918<div class="doc_subsubsection"> <a name="t_opaque">Opaque Type</a> </div>
1919<div class="doc_text">
1920
1921<h5>Overview:</h5>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1922<p>Opaque types are used to represent unknown types in the system. This
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1923 corresponds (for example) to the C notion of a forward declared structure
1924 type. In LLVM, opaque types can eventually be resolved to any type (not just
1925 a structure type).</p>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1926
1927<h5>Syntax:</h5>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1928<pre>
1929 opaque
1930</pre>
1931
1932<h5>Examples:</h5>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1933<table class="layout">
1934 <tr class="layout">
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]1935 <td class="left"><tt>opaque</tt></td>
1936 <td class="left">An opaque type.</td>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1937 </tr>
1938</table>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1939
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1940</div>
1941
Chris Lattnercf7a5842009-02-02 07:32:36 +0000[diff] [blame]1942<!-- ======================================================================= -->
1943<div class="doc_subsection">
1944 <a name="t_uprefs">Type Up-references</a>
1945</div>
1946
1947<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1948
Chris Lattnercf7a5842009-02-02 07:32:36 +0000[diff] [blame]1949<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1950<p>An "up reference" allows you to refer to a lexically enclosing type without
1951 requiring it to have a name. For instance, a structure declaration may
1952 contain a pointer to any of the types it is lexically a member of. Example
1953 of up references (with their equivalent as named type declarations)
1954 include:</p>
Chris Lattnercf7a5842009-02-02 07:32:36 +0000[diff] [blame]1955
1956<pre>
Chris Lattnerbf1d5452009-02-09 10:00:56 +0000[diff] [blame]1957 { \2 * } %x = type { %x* }
Chris Lattnercf7a5842009-02-02 07:32:36 +0000[diff] [blame]1958 { \2 }* %y = type { %y }*
1959 \1* %z = type %z*
1960</pre>
1961
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1962<p>An up reference is needed by the asmprinter for printing out cyclic types
1963 when there is no declared name for a type in the cycle. Because the
1964 asmprinter does not want to print out an infinite type string, it needs a
1965 syntax to handle recursive types that have no names (all names are optional
1966 in llvm IR).</p>
Chris Lattnercf7a5842009-02-02 07:32:36 +0000[diff] [blame]1967
1968<h5>Syntax:</h5>
1969<pre>
1970 \&lt;level&gt;
1971</pre>
1972
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1973<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]1974
1975<h5>Examples:</h5>
Chris Lattnercf7a5842009-02-02 07:32:36 +0000[diff] [blame]1976<table class="layout">
1977 <tr class="layout">
1978 <td class="left"><tt>\1*</tt></td>
1979 <td class="left">Self-referential pointer.</td>
1980 </tr>
1981 <tr class="layout">
1982 <td class="left"><tt>{ { \3*, i8 }, i32 }</tt></td>
1983 <td class="left">Recursive structure where the upref refers to the out-most
1984 structure.</td>
1985 </tr>
1986</table>
Chris Lattnercf7a5842009-02-02 07:32:36 +0000[diff] [blame]1987
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1988</div>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1989
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1990<!-- *********************************************************************** -->
1991<div class="doc_section"> <a name="constants">Constants</a> </div>
1992<!-- *********************************************************************** -->
1993
1994<div class="doc_text">
1995
1996<p>LLVM has several different basic types of constants. This section describes
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1997 them all and their syntax.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1998
1999</div>
2000
2001<!-- ======================================================================= -->
Reid Spencer8f08d802004-12-09 18:02:53 +0000[diff] [blame]2002<div class="doc_subsection"><a name="simpleconstants">Simple Constants</a></div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2003
2004<div class="doc_text">
2005
2006<dl>
2007 <dt><b>Boolean constants</b></dt>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2008 <dd>The two strings '<tt>true</tt>' and '<tt>false</tt>' are both valid
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]2009 constants of the <tt><a href="#t_integer">i1</a></tt> type.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2010
2011 <dt><b>Integer constants</b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2012 <dd>Standard integers (such as '4') are constants of
2013 the <a href="#t_integer">integer</a> type. Negative numbers may be used
2014 with integer types.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2015
2016 <dt><b>Floating point constants</b></dt>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2017 <dd>Floating point constants use standard decimal notation (e.g. 123.421),
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2018 exponential notation (e.g. 1.23421e+2), or a more precise hexadecimal
2019 notation (see below). The assembler requires the exact decimal value of a
2020 floating-point constant. For example, the assembler accepts 1.25 but
2021 rejects 1.3 because 1.3 is a repeating decimal in binary. Floating point
2022 constants must have a <a href="#t_floating">floating point</a> type. </dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2023
2024 <dt><b>Null pointer constants</b></dt>
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]2025 <dd>The identifier '<tt>null</tt>' is recognized as a null pointer constant
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2026 and must be of <a href="#t_pointer">pointer type</a>.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2027</dl>
2028
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2029<p>The one non-intuitive notation for constants is the hexadecimal form of
2030 floating point constants. For example, the form '<tt>double
2031 0x432ff973cafa8000</tt>' is equivalent to (but harder to read than)
2032 '<tt>double 4.5e+15</tt>'. The only time hexadecimal floating point
2033 constants are required (and the only time that they are generated by the
2034 disassembler) is when a floating point constant must be emitted but it cannot
2035 be represented as a decimal floating point number in a reasonable number of
2036 digits. For example, NaN's, infinities, and other special values are
2037 represented in their IEEE hexadecimal format so that assembly and disassembly
2038 do not cause any bits to change in the constants.</p>
2039
Dale Johannesencd4a3012009-02-11 22:14:51 +0000[diff] [blame]2040<p>When using the hexadecimal form, constants of types float and double are
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2041 represented using the 16-digit form shown above (which matches the IEEE754
2042 representation for double); float values must, however, be exactly
2043 representable as IEE754 single precision. Hexadecimal format is always used
2044 for long double, and there are three forms of long double. The 80-bit format
2045 used by x86 is represented as <tt>0xK</tt> followed by 20 hexadecimal digits.
2046 The 128-bit format used by PowerPC (two adjacent doubles) is represented
2047 by <tt>0xM</tt> followed by 32 hexadecimal digits. The IEEE 128-bit format
2048 is represented by <tt>0xL</tt> followed by 32 hexadecimal digits; no
2049 currently supported target uses this format. Long doubles will only work if
2050 they match the long double format on your target. All hexadecimal formats
2051 are big-endian (sign bit at the left).</p>
2052
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2053</div>
2054
2055<!-- ======================================================================= -->
Chris Lattner361bfcd2009-02-28 18:32:25 +0000[diff] [blame]2056<div class="doc_subsection">
Bill Wendling972b7202009-07-20 02:32:41 +0000[diff] [blame]2057<a name="aggregateconstants"></a> <!-- old anchor -->
2058<a name="complexconstants">Complex Constants</a>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2059</div>
2060
2061<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2062
Chris Lattner361bfcd2009-02-28 18:32:25 +0000[diff] [blame]2063<p>Complex constants are a (potentially recursive) combination of simple
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2064 constants and smaller complex constants.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2065
2066<dl>
2067 <dt><b>Structure constants</b></dt>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2068 <dd>Structure constants are represented with notation similar to structure
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2069 type definitions (a comma separated list of elements, surrounded by braces
2070 (<tt>{}</tt>)). For example: "<tt>{ i32 4, float 17.0, i32* @G }</tt>",
2071 where "<tt>@G</tt>" is declared as "<tt>@G = external global i32</tt>".
2072 Structure constants must have <a href="#t_struct">structure type</a>, and
2073 the number and types of elements must match those specified by the
2074 type.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2075
2076 <dt><b>Array constants</b></dt>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2077 <dd>Array constants are represented with notation similar to array type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2078 definitions (a comma separated list of elements, surrounded by square
2079 brackets (<tt>[]</tt>)). For example: "<tt>[ i32 42, i32 11, i32 74
2080 ]</tt>". Array constants must have <a href="#t_array">array type</a>, and
2081 the number and types of elements must match those specified by the
2082 type.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2083
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]2084 <dt><b>Vector constants</b></dt>
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]2085 <dd>Vector constants are represented with notation similar to vector type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2086 definitions (a comma separated list of elements, surrounded by
2087 less-than/greater-than's (<tt>&lt;&gt;</tt>)). For example: "<tt>&lt; i32
2088 42, i32 11, i32 74, i32 100 &gt;</tt>". Vector constants must
2089 have <a href="#t_vector">vector type</a>, and the number and types of
2090 elements must match those specified by the type.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2091
2092 <dt><b>Zero initialization</b></dt>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2093 <dd>The string '<tt>zeroinitializer</tt>' can be used to zero initialize a
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]2094 value to zero of <em>any</em> type, including scalar and
2095 <a href="#t_aggregate">aggregate</a> types.
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2096 This is often used to avoid having to print large zero initializers
2097 (e.g. for large arrays) and is always exactly equivalent to using explicit
2098 zero initializers.</dd>
Nick Lewycky49f89192009-04-04 07:22:01 +0000[diff] [blame]2099
2100 <dt><b>Metadata node</b></dt>
Nick Lewycky8e2c4f42009-05-30 16:08:30 +0000[diff] [blame]2101 <dd>A metadata node is a structure-like constant with
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2102 <a href="#t_metadata">metadata type</a>. For example: "<tt>metadata !{
2103 i32 0, metadata !"test" }</tt>". Unlike other constants that are meant to
2104 be interpreted as part of the instruction stream, metadata is a place to
2105 attach additional information such as debug info.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2106</dl>
2107
2108</div>
2109
2110<!-- ======================================================================= -->
2111<div class="doc_subsection">
2112 <a name="globalconstants">Global Variable and Function Addresses</a>
2113</div>
2114
2115<div class="doc_text">
2116
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2117<p>The addresses of <a href="#globalvars">global variables</a>
2118 and <a href="#functionstructure">functions</a> are always implicitly valid
2119 (link-time) constants. These constants are explicitly referenced when
2120 the <a href="#identifiers">identifier for the global</a> is used and always
2121 have <a href="#t_pointer">pointer</a> type. For example, the following is a
2122 legal LLVM file:</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2123
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2124<pre class="doc_code">
Chris Lattner00538a12007-06-06 18:28:13 +0000[diff] [blame]2125@X = global i32 17
2126@Y = global i32 42
2127@Z = global [2 x i32*] [ i32* @X, i32* @Y ]
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2128</pre>
2129
2130</div>
2131
2132<!-- ======================================================================= -->
Reid Spencer641f5c92004-12-09 18:13:12 +0000[diff] [blame]2133<div class="doc_subsection"><a name="undefvalues">Undefined Values</a></div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2134<div class="doc_text">
2135
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2136<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]2137 indicates that the user of the value may receive an unspecified bit-pattern.
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2138 Undefined values may be of any type (other than label or void) and be used
2139 anywhere a constant is permitted.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2140
Chris Lattner92ada5d2009-09-11 01:49:31 +0000[diff] [blame]2141<p>Undefined values are useful because they indicate to the compiler that the
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2142 program is well defined no matter what value is used. This gives the
2143 compiler more freedom to optimize. Here are some examples of (potentially
2144 surprising) transformations that are valid (in pseudo IR):</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2145
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2146
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2147<pre class="doc_code">
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2148 %A = add %X, undef
2149 %B = sub %X, undef
2150 %C = xor %X, undef
2151Safe:
2152 %A = undef
2153 %B = undef
2154 %C = undef
2155</pre>
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2156
2157<p>This is safe because all of the output bits are affected by the undef bits.
2158Any output bit can have a zero or one depending on the input bits.</p>
2159
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2160<pre class="doc_code">
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2161 %A = or %X, undef
2162 %B = and %X, undef
2163Safe:
2164 %A = -1
2165 %B = 0
2166Unsafe:
2167 %A = undef
2168 %B = undef
2169</pre>
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2170
2171<p>These logical operations have bits that are not always affected by the input.
2172For example, if "%X" has a zero bit, then the output of the 'and' operation will
2173always be a zero, no matter what the corresponding bit from the undef is. As
Chris Lattner92ada5d2009-09-11 01:49:31 +0000[diff] [blame]2174such, 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]2175However, it is safe to assume that all bits of the undef could be 0, and
2176optimize the and to 0. Likewise, it is safe to assume that all the bits of
2177the 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]2178-1.</p>
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2179
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2180<pre class="doc_code">
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2181 %A = select undef, %X, %Y
2182 %B = select undef, 42, %Y
2183 %C = select %X, %Y, undef
2184Safe:
2185 %A = %X (or %Y)
2186 %B = 42 (or %Y)
2187 %C = %Y
2188Unsafe:
2189 %A = undef
2190 %B = undef
2191 %C = undef
2192</pre>
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2193
2194<p>This set of examples show that undefined select (and conditional branch)
2195conditions can go "either way" but they have to come from one of the two
2196operands. In the %A example, if %X and %Y were both known to have a clear low
2197bit, then %A would have to have a cleared low bit. However, in the %C example,
2198the optimizer is allowed to assume that the undef operand could be the same as
2199%Y, allowing the whole select to be eliminated.</p>
2200
2201
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2202<pre class="doc_code">
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2203 %A = xor undef, undef
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]2204
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2205 %B = undef
2206 %C = xor %B, %B
2207
2208 %D = undef
2209 %E = icmp lt %D, 4
2210 %F = icmp gte %D, 4
2211
2212Safe:
2213 %A = undef
2214 %B = undef
2215 %C = undef
2216 %D = undef
2217 %E = undef
2218 %F = undef
2219</pre>
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2220
2221<p>This example points out that two undef operands are not necessarily the same.
2222This can be surprising to people (and also matches C semantics) where they
2223assume that "X^X" is always zero, even if X is undef. This isn't true for a
2224number of reasons, but the short answer is that an undef "variable" can
2225arbitrarily change its value over its "live range". This is true because the
2226"variable" doesn't actually <em>have a live range</em>. Instead, the value is
2227logically read from arbitrary registers that happen to be around when needed,
Benjamin Kramer0f420382009-10-12 14:46:08 +0000[diff] [blame]2228so the value is not necessarily consistent over time. In fact, %A and %C need
Chris Lattner6760e542009-09-08 15:13:16 +0000[diff] [blame]2229to have the same semantics or the core LLVM "replace all uses with" concept
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2230would not hold.</p>
Chris Lattnera34a7182009-09-07 23:33:52 +0000[diff] [blame]2231
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2232<pre class="doc_code">
Chris Lattnera34a7182009-09-07 23:33:52 +0000[diff] [blame]2233 %A = fdiv undef, %X
2234 %B = fdiv %X, undef
2235Safe:
2236 %A = undef
2237b: unreachable
2238</pre>
Chris Lattnera34a7182009-09-07 23:33:52 +0000[diff] [blame]2239
2240<p>These examples show the crucial difference between an <em>undefined
2241value</em> and <em>undefined behavior</em>. An undefined value (like undef) is
2242allowed to have an arbitrary bit-pattern. This means that the %A operation
2243can be constant folded to undef because the undef could be an SNaN, and fdiv is
2244not (currently) defined on SNaN's. However, in the second example, we can make
2245a more aggressive assumption: because the undef is allowed to be an arbitrary
2246value, 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]2247has <em>undefined behavior</em>, we are allowed to assume that the operation
Chris Lattnera34a7182009-09-07 23:33:52 +0000[diff] [blame]2248does not execute at all. This allows us to delete the divide and all code after
2249it: since the undefined operation "can't happen", the optimizer can assume that
2250it occurs in dead code.
2251</p>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]2252
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2253<pre class="doc_code">
Chris Lattnera34a7182009-09-07 23:33:52 +0000[diff] [blame]2254a: store undef -> %X
2255b: store %X -> undef
2256Safe:
2257a: &lt;deleted&gt;
2258b: unreachable
2259</pre>
Chris Lattnera34a7182009-09-07 23:33:52 +0000[diff] [blame]2260
2261<p>These examples reiterate the fdiv example: a store "of" an undefined value
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]2262can be assumed to not have any effect: we can assume that the value is
Chris Lattnera34a7182009-09-07 23:33:52 +0000[diff] [blame]2263overwritten with bits that happen to match what was already there. However, a
2264store "to" an undefined location could clobber arbitrary memory, therefore, it
2265has undefined behavior.</p>
2266
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2267</div>
2268
2269<!-- ======================================================================= -->
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]2270<div class="doc_subsection"><a name="trapvalues">Trap Values</a></div>
2271<div class="doc_text">
2272
Dan Gohmanb2a709b2010-04-26 20:21:21 +0000[diff] [blame]2273<p>Trap values are similar to <a href="#undefvalues">undef values</a>, however
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]2274 instead of representing an unspecified bit pattern, they represent the
2275 fact that an instruction or constant expression which cannot evoke side
2276 effects has nevertheless detected a condition which results in undefined
Dan Gohmanb2a709b2010-04-26 20:21:21 +0000[diff] [blame]2277 behavior.</p>
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]2278
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2279<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]2280 only exist when produced by operations such as
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2281 <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]2282
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2283<p>Trap value behavior is defined in terms of value <i>dependence</i>:</p>
Dan Gohmanb8b85c12010-04-26 23:36:52 +0000[diff] [blame]2284
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2285<ul>
2286<li>Values other than <a href="#i_phi"><tt>phi</tt></a> nodes depend on
2287 their operands.</li>
2288
2289<li><a href="#i_phi"><tt>Phi</tt></a> nodes depend on the operand corresponding
2290 to their dynamic predecessor basic block.</li>
2291
2292<li>Function arguments depend on the corresponding actual argument values in
2293 the dynamic callers of their functions.</li>
2294
2295<li><a href="#i_call"><tt>Call</tt></a> instructions depend on the
2296 <a href="#i_ret"><tt>ret</tt></a> instructions that dynamically transfer
2297 control back to them.</li>
2298
Dan Gohman7292a752010-05-03 14:55:22 +0000[diff] [blame]2299<li><a href="#i_invoke"><tt>Invoke</tt></a> instructions depend on the
2300 <a href="#i_ret"><tt>ret</tt></a>, <a href="#i_unwind"><tt>unwind</tt></a>,
2301 or exception-throwing call instructions that dynamically transfer control
2302 back to them.</li>
2303
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2304<li>Non-volatile loads and stores depend on the most recent stores to all of the
2305 referenced memory addresses, following the order in the IR
2306 (including loads and stores implied by intrinsics such as
2307 <a href="#int_memcpy"><tt>@llvm.memcpy</tt></a>.)</li>
2308
Dan Gohman3513ea52010-05-03 14:59:34 +0000[diff] [blame]2309<!-- TODO: In the case of multiple threads, this only applies if the store
2310 "happens-before" the load or store. -->
Dan Gohmanb8b85c12010-04-26 23:36:52 +0000[diff] [blame]2311
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2312<!-- TODO: floating-point exception state -->
Dan Gohmanb8b85c12010-04-26 23:36:52 +0000[diff] [blame]2313
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2314<li>An instruction with externally visible side effects depends on the most
2315 recent preceding instruction with externally visible side effects, following
Dan Gohman6c858db2010-07-06 15:26:33 +0000[diff] [blame]2316 the order in the IR. (This includes
2317 <a href="#volatile">volatile operations</a>.)</li>
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]2318
Dan Gohman7292a752010-05-03 14:55:22 +0000[diff] [blame]2319<li>An instruction <i>control-depends</i> on a
2320 <a href="#terminators">terminator instruction</a>
2321 if the terminator instruction has multiple successors and the instruction
2322 is always executed when control transfers to one of the successors, and
2323 may not be executed when control is transfered to another.</li>
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2324
2325<li>Dependence is transitive.</li>
2326
2327</ul>
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2328
2329<p>Whenever a trap value is generated, all values which depend on it evaluate
2330 to trap. If they have side effects, the evoke their side effects as if each
2331 operand with a trap value were undef. If they have externally-visible side
2332 effects, the behavior is undefined.</p>
2333
2334<p>Here are some examples:</p>
Dan Gohman48a25882010-04-26 20:54:53 +0000[diff] [blame]2335
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2336<pre class="doc_code">
Dan Gohmanb8b85c12010-04-26 23:36:52 +0000[diff] [blame]2337entry:
2338 %trap = sub nuw i32 0, 1 ; Results in a trap value.
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2339 %still_trap = and i32 %trap, 0 ; Whereas (and i32 undef, 0) would return 0.
2340 %trap_yet_again = getelementptr i32* @h, i32 %still_trap
2341 store i32 0, i32* %trap_yet_again ; undefined behavior
2342
2343 store i32 %trap, i32* @g ; Trap value conceptually stored to memory.
2344 %trap2 = load i32* @g ; Returns a trap value, not just undef.
2345
2346 volatile store i32 %trap, i32* @g ; External observation; undefined behavior.
2347
2348 %narrowaddr = bitcast i32* @g to i16*
2349 %wideaddr = bitcast i32* @g to i64*
2350 %trap3 = load 16* %narrowaddr ; Returns a trap value.
2351 %trap4 = load i64* %widaddr ; Returns a trap value.
2352
2353 %cmp = icmp i32 slt %trap, 0 ; Returns a trap value.
Dan Gohmanb8b85c12010-04-26 23:36:52 +0000[diff] [blame]2354 %br i1 %cmp, %true, %end ; Branch to either destination.
2355
2356true:
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2357 volatile store i32 0, i32* @g ; This is control-dependent on %cmp, so
2358 ; it has undefined behavior.
Dan Gohmanb8b85c12010-04-26 23:36:52 +0000[diff] [blame]2359 br label %end
2360
2361end:
2362 %p = phi i32 [ 0, %entry ], [ 1, %true ]
2363 ; Both edges into this PHI are
2364 ; control-dependent on %cmp, so this
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2365 ; always results in a trap value.
Dan Gohmanb8b85c12010-04-26 23:36:52 +0000[diff] [blame]2366
2367 volatile store i32 0, i32* @g ; %end is control-equivalent to %entry
2368 ; so this is defined (ignoring earlier
2369 ; undefined behavior in this example).
Dan Gohmanb8b85c12010-04-26 23:36:52 +0000[diff] [blame]2370</pre>
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]2371
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]2372</div>
2373
2374<!-- ======================================================================= -->
Chris Lattner2bfd3202009-10-27 21:19:13 +0000[diff] [blame]2375<div class="doc_subsection"><a name="blockaddress">Addresses of Basic
2376 Blocks</a></div>
Chris Lattnere4801f72009-10-27 21:01:34 +0000[diff] [blame]2377<div class="doc_text">
2378
Chris Lattneraa99c942009-11-01 01:27:45 +0000[diff] [blame]2379<p><b><tt>blockaddress(@function, %block)</tt></b></p>
Chris Lattnere4801f72009-10-27 21:01:34 +0000[diff] [blame]2380
2381<p>The '<tt>blockaddress</tt>' constant computes the address of the specified
Chris Lattner5c5f0ac2009-10-27 21:49:40 +0000[diff] [blame]2382 basic block in the specified function, and always has an i8* type. Taking
Chris Lattneraa99c942009-11-01 01:27:45 +0000[diff] [blame]2383 the address of the entry block is illegal.</p>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]2384
Chris Lattnere4801f72009-10-27 21:01:34 +0000[diff] [blame]2385<p>This value only has defined behavior when used as an operand to the
Chris Lattnerd04cb6d2009-10-28 00:19:10 +0000[diff] [blame]2386 '<a href="#i_indirectbr"><tt>indirectbr</tt></a>' instruction or for comparisons
Chris Lattnere4801f72009-10-27 21:01:34 +0000[diff] [blame]2387 against null. Pointer equality tests between labels addresses is undefined
2388 behavior - though, again, comparison against null is ok, and no label is
Chris Lattner2bfd3202009-10-27 21:19:13 +0000[diff] [blame]2389 equal to the null pointer. This may also be passed around as an opaque
2390 pointer sized value as long as the bits are not inspected. This allows
Chris Lattnerda37b302009-10-27 21:44:20 +0000[diff] [blame]2391 <tt>ptrtoint</tt> and arithmetic to be performed on these values so long as
Chris Lattnerd04cb6d2009-10-28 00:19:10 +0000[diff] [blame]2392 the original value is reconstituted before the <tt>indirectbr</tt>.</p>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]2393
Chris Lattner2bfd3202009-10-27 21:19:13 +0000[diff] [blame]2394<p>Finally, some targets may provide defined semantics when
Chris Lattnere4801f72009-10-27 21:01:34 +0000[diff] [blame]2395 using the value as the operand to an inline assembly, but that is target
2396 specific.
2397 </p>
2398
2399</div>
2400
2401
2402<!-- ======================================================================= -->
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2403<div class="doc_subsection"><a name="constantexprs">Constant Expressions</a>
2404</div>
2405
2406<div class="doc_text">
2407
2408<p>Constant expressions are used to allow expressions involving other constants
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2409 to be used as constants. Constant expressions may be of
2410 any <a href="#t_firstclass">first class</a> type and may involve any LLVM
2411 operation that does not have side effects (e.g. load and call are not
2412 supported). The following is the syntax for constant expressions:</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2413
2414<dl>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2415 <dt><b><tt>trunc (CST to TYPE)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2416 <dd>Truncate a constant to another type. The bit size of CST must be larger
2417 than the bit size of TYPE. Both types must be integers.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2418
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2419 <dt><b><tt>zext (CST to TYPE)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2420 <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]2421 smaller than the bit size of TYPE. Both types must be integers.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2422
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2423 <dt><b><tt>sext (CST to TYPE)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2424 <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]2425 smaller than the bit size of TYPE. Both types must be integers.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2426
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2427 <dt><b><tt>fptrunc (CST to TYPE)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2428 <dd>Truncate a floating point constant to another floating point type. The
2429 size of CST must be larger than the size of TYPE. Both types must be
2430 floating point.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2431
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2432 <dt><b><tt>fpext (CST to TYPE)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2433 <dd>Floating point extend a constant to another type. The size of CST must be
2434 smaller or equal to the size of TYPE. Both types must be floating
2435 point.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2436
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2437 <dt><b><tt>fptoui (CST to TYPE)</tt></b></dt>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2438 <dd>Convert a floating point constant to the corresponding unsigned integer
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2439 constant. TYPE must be a scalar or vector integer type. CST must be of
2440 scalar or vector floating point type. Both CST and TYPE must be scalars,
2441 or vectors of the same number of elements. If the value won't fit in the
2442 integer type, the results are undefined.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2443
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2444 <dt><b><tt>fptosi (CST to TYPE)</tt></b></dt>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2445 <dd>Convert a floating point constant to the corresponding signed integer
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2446 constant. TYPE must be a scalar or vector integer type. CST must be of
2447 scalar or vector floating point type. Both CST and TYPE must be scalars,
2448 or vectors of the same number of elements. If the value won't fit in the
2449 integer type, the results are undefined.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2450
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2451 <dt><b><tt>uitofp (CST to TYPE)</tt></b></dt>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2452 <dd>Convert an unsigned integer constant to the corresponding floating point
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2453 constant. TYPE must be a scalar or vector floating point type. CST must be
2454 of scalar or vector integer type. Both CST and TYPE must be scalars, or
2455 vectors of the same number of elements. If the value won't fit in the
2456 floating point type, the results are undefined.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2457
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2458 <dt><b><tt>sitofp (CST to TYPE)</tt></b></dt>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2459 <dd>Convert a signed integer constant to the corresponding floating point
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2460 constant. TYPE must be a scalar or vector floating point type. CST must be
2461 of scalar or vector integer type. Both CST and TYPE must be scalars, or
2462 vectors of the same number of elements. If the value won't fit in the
2463 floating point type, the results are undefined.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2464
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2465 <dt><b><tt>ptrtoint (CST to TYPE)</tt></b></dt>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]2466 <dd>Convert a pointer typed constant to the corresponding integer constant
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2467 <tt>TYPE</tt> must be an integer type. <tt>CST</tt> must be of pointer
2468 type. The <tt>CST</tt> value is zero extended, truncated, or unchanged to
2469 make it fit in <tt>TYPE</tt>.</dd>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]2470
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2471 <dt><b><tt>inttoptr (CST to TYPE)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2472 <dd>Convert a integer constant to a pointer constant. TYPE must be a pointer
2473 type. CST must be of integer type. The CST value is zero extended,
2474 truncated, or unchanged to make it fit in a pointer size. This one is
2475 <i>really</i> dangerous!</dd>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]2476
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2477 <dt><b><tt>bitcast (CST to TYPE)</tt></b></dt>
Chris Lattner789dee32009-02-28 18:27:03 +0000[diff] [blame]2478 <dd>Convert a constant, CST, to another TYPE. The constraints of the operands
2479 are the same as those for the <a href="#i_bitcast">bitcast
2480 instruction</a>.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2481
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2482 <dt><b><tt>getelementptr (CSTPTR, IDX0, IDX1, ...)</tt></b></dt>
2483 <dt><b><tt>getelementptr inbounds (CSTPTR, IDX0, IDX1, ...)</tt></b></dt>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2484 <dd>Perform the <a href="#i_getelementptr">getelementptr operation</a> on
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2485 constants. As with the <a href="#i_getelementptr">getelementptr</a>
2486 instruction, the index list may have zero or more indexes, which are
2487 required to make sense for the type of "CSTPTR".</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2488
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2489 <dt><b><tt>select (COND, VAL1, VAL2)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2490 <dd>Perform the <a href="#i_select">select operation</a> on constants.</dd>
Reid Spencer9965ee72006-12-04 19:23:19 +0000[diff] [blame]2491
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2492 <dt><b><tt>icmp COND (VAL1, VAL2)</tt></b></dt>
Reid Spencer9965ee72006-12-04 19:23:19 +0000[diff] [blame]2493 <dd>Performs the <a href="#i_icmp">icmp operation</a> on constants.</dd>
2494
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2495 <dt><b><tt>fcmp COND (VAL1, VAL2)</tt></b></dt>
Reid Spencer9965ee72006-12-04 19:23:19 +0000[diff] [blame]2496 <dd>Performs the <a href="#i_fcmp">fcmp operation</a> on constants.</dd>
Robert Bocchino7e97a6d2006-01-10 19:31:34 +0000[diff] [blame]2497
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2498 <dt><b><tt>extractelement (VAL, IDX)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2499 <dd>Perform the <a href="#i_extractelement">extractelement operation</a> on
2500 constants.</dd>
Robert Bocchino7e97a6d2006-01-10 19:31:34 +0000[diff] [blame]2501
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2502 <dt><b><tt>insertelement (VAL, ELT, IDX)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2503 <dd>Perform the <a href="#i_insertelement">insertelement operation</a> on
2504 constants.</dd>
Chris Lattner016a0e52006-04-08 00:13:41 +0000[diff] [blame]2505
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2506 <dt><b><tt>shufflevector (VEC1, VEC2, IDXMASK)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2507 <dd>Perform the <a href="#i_shufflevector">shufflevector operation</a> on
2508 constants.</dd>
Chris Lattner016a0e52006-04-08 00:13:41 +0000[diff] [blame]2509
Nick Lewycky9ab9a7f2010-05-29 06:44:15 +0000[diff] [blame]2510 <dt><b><tt>extractvalue (VAL, IDX0, IDX1, ...)</tt></b></dt>
2511 <dd>Perform the <a href="#i_extractvalue">extractvalue operation</a> on
2512 constants. The index list is interpreted in a similar manner as indices in
2513 a '<a href="#i_getelementptr">getelementptr</a>' operation. At least one
2514 index value must be specified.</dd>
2515
2516 <dt><b><tt>insertvalue (VAL, ELT, IDX0, IDX1, ...)</tt></b></dt>
2517 <dd>Perform the <a href="#i_insertvalue">insertvalue operation</a> on
2518 constants. The index list is interpreted in a similar manner as indices in
2519 a '<a href="#i_getelementptr">getelementptr</a>' operation. At least one
2520 index value must be specified.</dd>
2521
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2522 <dt><b><tt>OPCODE (LHS, RHS)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2523 <dd>Perform the specified operation of the LHS and RHS constants. OPCODE may
2524 be any of the <a href="#binaryops">binary</a>
2525 or <a href="#bitwiseops">bitwise binary</a> operations. The constraints
2526 on operands are the same as those for the corresponding instruction
2527 (e.g. no bitwise operations on floating point values are allowed).</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2528</dl>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2529
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2530</div>
Chris Lattnerb1652612004-03-08 16:49:10 +0000[diff] [blame]2531
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2532<!-- *********************************************************************** -->
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2533<div class="doc_section"> <a name="othervalues">Other Values</a> </div>
2534<!-- *********************************************************************** -->
2535
2536<!-- ======================================================================= -->
2537<div class="doc_subsection">
2538<a name="inlineasm">Inline Assembler Expressions</a>
2539</div>
2540
2541<div class="doc_text">
2542
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2543<p>LLVM supports inline assembler expressions (as opposed
2544 to <a href="#moduleasm"> Module-Level Inline Assembly</a>) through the use of
2545 a special value. This value represents the inline assembler as a string
2546 (containing the instructions to emit), a list of operand constraints (stored
Dale Johannesen63c94fe2009-10-13 21:56:55 +0000[diff] [blame]2547 as a string), a flag that indicates whether or not the inline asm
Dale Johannesen1cfb9582009-10-21 23:28:00 +0000[diff] [blame]2548 expression has side effects, and a flag indicating whether the function
2549 containing the asm needs to align its stack conservatively. An example
2550 inline assembler expression is:</p>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2551
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2552<pre class="doc_code">
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2553i32 (i32) asm "bswap $0", "=r,r"
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2554</pre>
2555
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2556<p>Inline assembler expressions may <b>only</b> be used as the callee operand of
2557 a <a href="#i_call"><tt>call</tt> instruction</a>. Thus, typically we
2558 have:</p>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2559
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2560<pre class="doc_code">
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2561%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]2562</pre>
2563
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2564<p>Inline asms with side effects not visible in the constraint list must be
2565 marked as having side effects. This is done through the use of the
2566 '<tt>sideeffect</tt>' keyword, like so:</p>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2567
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2568<pre class="doc_code">
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2569call void asm sideeffect "eieio", ""()
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2570</pre>
2571
Dale Johannesen1cfb9582009-10-21 23:28:00 +0000[diff] [blame]2572<p>In some cases inline asms will contain code that will not work unless the
2573 stack is aligned in some way, such as calls or SSE instructions on x86,
2574 yet will not contain code that does that alignment within the asm.
2575 The compiler should make conservative assumptions about what the asm might
2576 contain and should generate its usual stack alignment code in the prologue
2577 if the '<tt>alignstack</tt>' keyword is present:</p>
Dale Johannesen63c94fe2009-10-13 21:56:55 +0000[diff] [blame]2578
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2579<pre class="doc_code">
Dale Johannesen1cfb9582009-10-21 23:28:00 +0000[diff] [blame]2580call void asm alignstack "eieio", ""()
Dale Johannesen63c94fe2009-10-13 21:56:55 +0000[diff] [blame]2581</pre>
Dale Johannesen63c94fe2009-10-13 21:56:55 +0000[diff] [blame]2582
2583<p>If both keywords appear the '<tt>sideeffect</tt>' keyword must come
2584 first.</p>
2585
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2586<p>TODO: The format of the asm and constraints string still need to be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2587 documented here. Constraints on what can be done (e.g. duplication, moving,
2588 etc need to be documented). This is probably best done by reference to
2589 another document that covers inline asm from a holistic perspective.</p>
Chris Lattner51065562010-04-07 05:38:05 +0000[diff] [blame]2590</div>
2591
2592<div class="doc_subsubsection">
2593<a name="inlineasm_md">Inline Asm Metadata</a>
2594</div>
2595
2596<div class="doc_text">
2597
2598<p>The call instructions that wrap inline asm nodes may have a "!srcloc" MDNode
2599 attached to it that contains a constant integer. If present, the code
2600 generator will use the integer as the location cookie value when report
2601 errors through the LLVMContext error reporting mechanisms. This allows a
Dan Gohman61110ae2010-04-28 00:36:01 +0000[diff] [blame]2602 front-end to correlate backend errors that occur with inline asm back to the
Chris Lattner51065562010-04-07 05:38:05 +0000[diff] [blame]2603 source code that produced it. For example:</p>
2604
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2605<pre class="doc_code">
Chris Lattner51065562010-04-07 05:38:05 +0000[diff] [blame]2606call void asm sideeffect "something bad", ""()<b>, !srcloc !42</b>
2607...
2608!42 = !{ i32 1234567 }
2609</pre>
Chris Lattner51065562010-04-07 05:38:05 +0000[diff] [blame]2610
2611<p>It is up to the front-end to make sense of the magic numbers it places in the
2612 IR.</p>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2613
2614</div>
2615
Chris Lattnerc2f8f162010-01-15 21:50:19 +0000[diff] [blame]2616<!-- ======================================================================= -->
2617<div class="doc_subsection"><a name="metadata">Metadata Nodes and Metadata
2618 Strings</a>
2619</div>
2620
2621<div class="doc_text">
2622
2623<p>LLVM IR allows metadata to be attached to instructions in the program that
2624 can convey extra information about the code to the optimizers and code
2625 generator. One example application of metadata is source-level debug
2626 information. There are two metadata primitives: strings and nodes. All
2627 metadata has the <tt>metadata</tt> type and is identified in syntax by a
2628 preceding exclamation point ('<tt>!</tt>').</p>
2629
2630<p>A metadata string is a string surrounded by double quotes. It can contain
2631 any character by escaping non-printable characters with "\xx" where "xx" is
2632 the two digit hex code. For example: "<tt>!"test\00"</tt>".</p>
2633
2634<p>Metadata nodes are represented with notation similar to structure constants
2635 (a comma separated list of elements, surrounded by braces and preceded by an
2636 exclamation point). For example: "<tt>!{ metadata !"test\00", i32
2637 10}</tt>". Metadata nodes can have any values as their operand.</p>
2638
2639<p>A <a href="#namedmetadatastructure">named metadata</a> is a collection of
2640 metadata nodes, which can be looked up in the module symbol table. For
2641 example: "<tt>!foo = metadata !{!4, !3}</tt>".
2642
Devang Patel9984bd62010-03-04 23:44:48 +0000[diff] [blame]2643<p>Metadata can be used as function arguments. Here <tt>llvm.dbg.value</tt>
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2644 function is using two metadata arguments.</p>
Devang Patel9984bd62010-03-04 23:44:48 +0000[diff] [blame]2645
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2646 <pre class="doc_code">
Devang Patel9984bd62010-03-04 23:44:48 +0000[diff] [blame]2647 call void @llvm.dbg.value(metadata !24, i64 0, metadata !25)
2648 </pre>
Devang Patel9984bd62010-03-04 23:44:48 +0000[diff] [blame]2649
2650<p>Metadata can be attached with an instruction. Here metadata <tt>!21</tt> is
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2651 attached with <tt>add</tt> instruction using <tt>!dbg</tt> identifier.</p>
Devang Patel9984bd62010-03-04 23:44:48 +0000[diff] [blame]2652
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2653 <pre class="doc_code">
Devang Patel9984bd62010-03-04 23:44:48 +0000[diff] [blame]2654 %indvar.next = add i64 %indvar, 1, !dbg !21
2655 </pre>
Chris Lattnerc2f8f162010-01-15 21:50:19 +0000[diff] [blame]2656</div>
2657
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]2658
2659<!-- *********************************************************************** -->
2660<div class="doc_section">
2661 <a name="intrinsic_globals">Intrinsic Global Variables</a>
2662</div>
2663<!-- *********************************************************************** -->
2664
2665<p>LLVM has a number of "magic" global variables that contain data that affect
2666code generation or other IR semantics. These are documented here. All globals
Chris Lattner58f9bb22009-07-20 06:14:25 +0000[diff] [blame]2667of this sort should have a section specified as "<tt>llvm.metadata</tt>". This
2668section and all globals that start with "<tt>llvm.</tt>" are reserved for use
2669by LLVM.</p>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]2670
2671<!-- ======================================================================= -->
2672<div class="doc_subsection">
2673<a name="intg_used">The '<tt>llvm.used</tt>' Global Variable</a>
2674</div>
2675
2676<div class="doc_text">
2677
2678<p>The <tt>@llvm.used</tt> global is an array with i8* element type which has <a
2679href="#linkage_appending">appending linkage</a>. This array contains a list of
2680pointers to global variables and functions which may optionally have a pointer
2681cast formed of bitcast or getelementptr. For example, a legal use of it is:</p>
2682
2683<pre>
2684 @X = global i8 4
2685 @Y = global i32 123
2686
2687 @llvm.used = appending global [2 x i8*] [
2688 i8* @X,
2689 i8* bitcast (i32* @Y to i8*)
2690 ], section "llvm.metadata"
2691</pre>
2692
2693<p>If a global variable appears in the <tt>@llvm.used</tt> list, then the
2694compiler, assembler, and linker are required to treat the symbol as if there is
2695a reference to the global that it cannot see. For example, if a variable has
2696internal linkage and no references other than that from the <tt>@llvm.used</tt>
2697list, it cannot be deleted. This is commonly used to represent references from
2698inline asms and other things the compiler cannot "see", and corresponds to
2699"attribute((used))" in GNU C.</p>
2700
2701<p>On some targets, the code generator must emit a directive to the assembler or
2702object file to prevent the assembler and linker from molesting the symbol.</p>
2703
2704</div>
2705
2706<!-- ======================================================================= -->
2707<div class="doc_subsection">
Chris Lattner58f9bb22009-07-20 06:14:25 +0000[diff] [blame]2708<a name="intg_compiler_used">The '<tt>llvm.compiler.used</tt>' Global Variable</a>
2709</div>
2710
2711<div class="doc_text">
2712
2713<p>The <tt>@llvm.compiler.used</tt> directive is the same as the
2714<tt>@llvm.used</tt> directive, except that it only prevents the compiler from
2715touching the symbol. On targets that support it, this allows an intelligent
2716linker to optimize references to the symbol without being impeded as it would be
2717by <tt>@llvm.used</tt>.</p>
2718
2719<p>This is a rare construct that should only be used in rare circumstances, and
2720should not be exposed to source languages.</p>
2721
2722</div>
2723
2724<!-- ======================================================================= -->
2725<div class="doc_subsection">
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]2726<a name="intg_global_ctors">The '<tt>llvm.global_ctors</tt>' Global Variable</a>
2727</div>
2728
2729<div class="doc_text">
David Chisnalla9d4a6f2010-04-30 19:23:49 +0000[diff] [blame]2730<pre>
2731%0 = type { i32, void ()* }
David Chisnallb492b812010-04-30 19:27:35 +0000[diff] [blame]2732@llvm.global_ctors = appending global [1 x %0] [%0 { i32 65535, void ()* @ctor }]
David Chisnalla9d4a6f2010-04-30 19:23:49 +0000[diff] [blame]2733</pre>
2734<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.
2735</p>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]2736
2737</div>
2738
2739<!-- ======================================================================= -->
2740<div class="doc_subsection">
2741<a name="intg_global_dtors">The '<tt>llvm.global_dtors</tt>' Global Variable</a>
2742</div>
2743
2744<div class="doc_text">
David Chisnalla9d4a6f2010-04-30 19:23:49 +0000[diff] [blame]2745<pre>
2746%0 = type { i32, void ()* }
David Chisnallb492b812010-04-30 19:27:35 +0000[diff] [blame]2747@llvm.global_dtors = appending global [1 x %0] [%0 { i32 65535, void ()* @dtor }]
David Chisnalla9d4a6f2010-04-30 19:23:49 +0000[diff] [blame]2748</pre>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]2749
David Chisnalla9d4a6f2010-04-30 19:23:49 +0000[diff] [blame]2750<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.
2751</p>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]2752
2753</div>
2754
2755
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2756<!-- *********************************************************************** -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2757<div class="doc_section"> <a name="instref">Instruction Reference</a> </div>
2758<!-- *********************************************************************** -->
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2759
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2760<div class="doc_text">
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2761
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2762<p>The LLVM instruction set consists of several different classifications of
2763 instructions: <a href="#terminators">terminator
2764 instructions</a>, <a href="#binaryops">binary instructions</a>,
2765 <a href="#bitwiseops">bitwise binary instructions</a>,
2766 <a href="#memoryops">memory instructions</a>, and
2767 <a href="#otherops">other instructions</a>.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2768
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2769</div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2770
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2771<!-- ======================================================================= -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2772<div class="doc_subsection"> <a name="terminators">Terminator
2773Instructions</a> </div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2774
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2775<div class="doc_text">
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2776
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2777<p>As mentioned <a href="#functionstructure">previously</a>, every basic block
2778 in a program ends with a "Terminator" instruction, which indicates which
2779 block should be executed after the current block is finished. These
2780 terminator instructions typically yield a '<tt>void</tt>' value: they produce
2781 control flow, not values (the one exception being the
2782 '<a href="#i_invoke"><tt>invoke</tt></a>' instruction).</p>
2783
Duncan Sands626b0242010-04-15 20:35:54 +0000[diff] [blame]2784<p>There are seven different terminator instructions: the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2785 '<a href="#i_ret"><tt>ret</tt></a>' instruction, the
2786 '<a href="#i_br"><tt>br</tt></a>' instruction, the
2787 '<a href="#i_switch"><tt>switch</tt></a>' instruction, the
Bill Wendling33fef7e2009-11-02 00:25:26 +0000[diff] [blame]2788 '<a href="#i_indirectbr">'<tt>indirectbr</tt></a>' Instruction, the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2789 '<a href="#i_invoke"><tt>invoke</tt></a>' instruction, the
2790 '<a href="#i_unwind"><tt>unwind</tt></a>' instruction, and the
2791 '<a href="#i_unreachable"><tt>unreachable</tt></a>' instruction.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2792
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2793</div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2794
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2795<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2796<div class="doc_subsubsection"> <a name="i_ret">'<tt>ret</tt>'
2797Instruction</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2798
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2799<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2800
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2801<h5>Syntax:</h5>
Dan Gohmancc3132e2008-10-04 19:00:07 +0000[diff] [blame]2802<pre>
2803 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]2804 ret void <i>; Return from void function</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2805</pre>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]2806
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2807<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2808<p>The '<tt>ret</tt>' instruction is used to return control flow (and optionally
2809 a value) from a function back to the caller.</p>
2810
2811<p>There are two forms of the '<tt>ret</tt>' instruction: one that returns a
2812 value and then causes control flow, and one that just causes control flow to
2813 occur.</p>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]2814
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2815<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2816<p>The '<tt>ret</tt>' instruction optionally accepts a single argument, the
2817 return value. The type of the return value must be a
2818 '<a href="#t_firstclass">first class</a>' type.</p>
Dan Gohmancc3132e2008-10-04 19:00:07 +0000[diff] [blame]2819
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2820<p>A function is not <a href="#wellformed">well formed</a> if it it has a
2821 non-void return type and contains a '<tt>ret</tt>' instruction with no return
2822 value or a return value with a type that does not match its type, or if it
2823 has a void return type and contains a '<tt>ret</tt>' instruction with a
2824 return value.</p>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]2825
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2826<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2827<p>When the '<tt>ret</tt>' instruction is executed, control flow returns back to
2828 the calling function's context. If the caller is a
2829 "<a href="#i_call"><tt>call</tt></a>" instruction, execution continues at the
2830 instruction after the call. If the caller was an
2831 "<a href="#i_invoke"><tt>invoke</tt></a>" instruction, execution continues at
2832 the beginning of the "normal" destination block. If the instruction returns
2833 a value, that value shall set the call or invoke instruction's return
2834 value.</p>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]2835
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2836<h5>Example:</h5>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]2837<pre>
2838 ret i32 5 <i>; Return an integer value of 5</i>
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]2839 ret void <i>; Return from a void function</i>
Bill Wendling050ee8f2009-02-28 22:12:54 +0000[diff] [blame]2840 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]2841</pre>
Dan Gohman3065b612009-01-12 23:12:39 +0000[diff] [blame]2842
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2843</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2844<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2845<div class="doc_subsubsection"> <a name="i_br">'<tt>br</tt>' Instruction</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2846
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2847<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2848
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2849<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2850<pre>
2851 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]2852</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2853
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2854<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2855<p>The '<tt>br</tt>' instruction is used to cause control flow to transfer to a
2856 different basic block in the current function. There are two forms of this
2857 instruction, corresponding to a conditional branch and an unconditional
2858 branch.</p>
2859
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2860<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2861<p>The conditional branch form of the '<tt>br</tt>' instruction takes a single
2862 '<tt>i1</tt>' value and two '<tt>label</tt>' values. The unconditional form
2863 of the '<tt>br</tt>' instruction takes a single '<tt>label</tt>' value as a
2864 target.</p>
2865
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2866<h5>Semantics:</h5>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]2867<p>Upon execution of a conditional '<tt>br</tt>' instruction, the '<tt>i1</tt>'
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2868 argument is evaluated. If the value is <tt>true</tt>, control flows to the
2869 '<tt>iftrue</tt>' <tt>label</tt> argument. If "cond" is <tt>false</tt>,
2870 control flows to the '<tt>iffalse</tt>' <tt>label</tt> argument.</p>
2871
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2872<h5>Example:</h5>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]2873<pre>
2874Test:
2875 %cond = <a href="#i_icmp">icmp</a> eq i32 %a, %b
2876 br i1 %cond, label %IfEqual, label %IfUnequal
2877IfEqual:
2878 <a href="#i_ret">ret</a> i32 1
2879IfUnequal:
2880 <a href="#i_ret">ret</a> i32 0
2881</pre>
2882
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2883</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2884
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2885<!-- _______________________________________________________________________ -->
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2886<div class="doc_subsubsection">
2887 <a name="i_switch">'<tt>switch</tt>' Instruction</a>
2888</div>
2889
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2890<div class="doc_text">
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2891
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2892<h5>Syntax:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2893<pre>
2894 switch &lt;intty&gt; &lt;value&gt;, label &lt;defaultdest&gt; [ &lt;intty&gt; &lt;val&gt;, label &lt;dest&gt; ... ]
2895</pre>
2896
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2897<h5>Overview:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2898<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]2899 several different places. It is a generalization of the '<tt>br</tt>'
2900 instruction, allowing a branch to occur to one of many possible
2901 destinations.</p>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2902
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2903<h5>Arguments:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2904<p>The '<tt>switch</tt>' instruction uses three parameters: an integer
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2905 comparison value '<tt>value</tt>', a default '<tt>label</tt>' destination,
2906 and an array of pairs of comparison value constants and '<tt>label</tt>'s.
2907 The table is not allowed to contain duplicate constant entries.</p>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2908
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2909<h5>Semantics:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2910<p>The <tt>switch</tt> instruction specifies a table of values and
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2911 destinations. When the '<tt>switch</tt>' instruction is executed, this table
2912 is searched for the given value. If the value is found, control flow is
Benjamin Kramer0f420382009-10-12 14:46:08 +0000[diff] [blame]2913 transferred to the corresponding destination; otherwise, control flow is
2914 transferred to the default destination.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2915
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2916<h5>Implementation:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2917<p>Depending on properties of the target machine and the particular
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2918 <tt>switch</tt> instruction, this instruction may be code generated in
2919 different ways. For example, it could be generated as a series of chained
2920 conditional branches or with a lookup table.</p>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2921
2922<h5>Example:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2923<pre>
2924 <i>; Emulate a conditional br instruction</i>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]2925 %Val = <a href="#i_zext">zext</a> i1 %value to i32
Dan Gohman623806e2009-01-04 23:44:43 +0000[diff] [blame]2926 switch i32 %Val, label %truedest [ i32 0, label %falsedest ]
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2927
2928 <i>; Emulate an unconditional br instruction</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2929 switch i32 0, label %dest [ ]
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2930
2931 <i>; Implement a jump table:</i>
Dan Gohman623806e2009-01-04 23:44:43 +0000[diff] [blame]2932 switch i32 %val, label %otherwise [ i32 0, label %onzero
2933 i32 1, label %onone
2934 i32 2, label %ontwo ]
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2935</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2936
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2937</div>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]2938
Chris Lattner3ed871f2009-10-27 19:13:16 +0000[diff] [blame]2939
2940<!-- _______________________________________________________________________ -->
2941<div class="doc_subsubsection">
Chris Lattnerd04cb6d2009-10-28 00:19:10 +0000[diff] [blame]2942 <a name="i_indirectbr">'<tt>indirectbr</tt>' Instruction</a>
Chris Lattner3ed871f2009-10-27 19:13:16 +0000[diff] [blame]2943</div>
2944
2945<div class="doc_text">
2946
2947<h5>Syntax:</h5>
2948<pre>
Chris Lattnerd04cb6d2009-10-28 00:19:10 +0000[diff] [blame]2949 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]2950</pre>
2951
2952<h5>Overview:</h5>
2953
Chris Lattnerd04cb6d2009-10-28 00:19:10 +0000[diff] [blame]2954<p>The '<tt>indirectbr</tt>' instruction implements an indirect branch to a label
Chris Lattner3ed871f2009-10-27 19:13:16 +0000[diff] [blame]2955 within the current function, whose address is specified by
Chris Lattnere4801f72009-10-27 21:01:34 +0000[diff] [blame]2956 "<tt>address</tt>". Address must be derived from a <a
2957 href="#blockaddress">blockaddress</a> constant.</p>
Chris Lattner3ed871f2009-10-27 19:13:16 +0000[diff] [blame]2958
2959<h5>Arguments:</h5>
2960
2961<p>The '<tt>address</tt>' argument is the address of the label to jump to. The
2962 rest of the arguments indicate the full set of possible destinations that the
2963 address may point to. Blocks are allowed to occur multiple times in the
2964 destination list, though this isn't particularly useful.</p>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]2965
Chris Lattner3ed871f2009-10-27 19:13:16 +0000[diff] [blame]2966<p>This destination list is required so that dataflow analysis has an accurate
2967 understanding of the CFG.</p>
2968
2969<h5>Semantics:</h5>
2970
2971<p>Control transfers to the block specified in the address argument. All
2972 possible destination blocks must be listed in the label list, otherwise this
2973 instruction has undefined behavior. This implies that jumps to labels
2974 defined in other functions have undefined behavior as well.</p>
2975
2976<h5>Implementation:</h5>
2977
2978<p>This is typically implemented with a jump through a register.</p>
2979
2980<h5>Example:</h5>
2981<pre>
Chris Lattnerd04cb6d2009-10-28 00:19:10 +0000[diff] [blame]2982 indirectbr i8* %Addr, [ label %bb1, label %bb2, label %bb3 ]
Chris Lattner3ed871f2009-10-27 19:13:16 +0000[diff] [blame]2983</pre>
2984
2985</div>
2986
2987
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2988<!-- _______________________________________________________________________ -->
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]2989<div class="doc_subsubsection">
2990 <a name="i_invoke">'<tt>invoke</tt>' Instruction</a>
2991</div>
2992
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2993<div class="doc_text">
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]2994
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2995<h5>Syntax:</h5>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]2996<pre>
Devang Patel02256232008-10-07 17:48:33 +0000[diff] [blame]2997 &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]2998 to label &lt;normal label&gt; unwind label &lt;exception label&gt;
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]2999</pre>
3000
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]3001<h5>Overview:</h5>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3002<p>The '<tt>invoke</tt>' instruction causes control to transfer to a specified
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3003 function, with the possibility of control flow transfer to either the
3004 '<tt>normal</tt>' label or the '<tt>exception</tt>' label. If the callee
3005 function returns with the "<tt><a href="#i_ret">ret</a></tt>" instruction,
3006 control flow will return to the "normal" label. If the callee (or any
3007 indirect callees) returns with the "<a href="#i_unwind"><tt>unwind</tt></a>"
3008 instruction, control is interrupted and continued at the dynamically nearest
3009 "exception" label.</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3010
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3011<h5>Arguments:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3012<p>This instruction requires several arguments:</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3013
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3014<ol>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3015 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
3016 convention</a> the call should use. If none is specified, the call
3017 defaults to using C calling conventions.</li>
Devang Patel7e9b05e2008-10-06 18:50:38 +0000[diff] [blame]3018
3019 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3020 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
3021 '<tt>inreg</tt>' attributes are valid here.</li>
Devang Patel7e9b05e2008-10-06 18:50:38 +0000[diff] [blame]3022
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3023 <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]3024 function value being invoked. In most cases, this is a direct function
3025 invocation, but indirect <tt>invoke</tt>s are just as possible, branching
3026 off an arbitrary pointer to function value.</li>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3027
3028 <li>'<tt>function ptr val</tt>': An LLVM value containing a pointer to a
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3029 function to be invoked. </li>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3030
3031 <li>'<tt>function args</tt>': argument list whose types match the function
Chris Lattner47f2a832010-03-02 06:36:51 +0000[diff] [blame]3032 signature argument types and parameter attributes. All arguments must be
3033 of <a href="#t_firstclass">first class</a> type. If the function
3034 signature indicates the function accepts a variable number of arguments,
3035 the extra arguments can be specified.</li>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3036
3037 <li>'<tt>normal label</tt>': the label reached when the called function
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3038 executes a '<tt><a href="#i_ret">ret</a></tt>' instruction. </li>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3039
3040 <li>'<tt>exception label</tt>': the label reached when a callee returns with
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3041 the <a href="#i_unwind"><tt>unwind</tt></a> instruction. </li>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3042
Devang Patel02256232008-10-07 17:48:33 +0000[diff] [blame]3043 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3044 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
3045 '<tt>readnone</tt>' attributes are valid here.</li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3046</ol>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3047
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3048<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3049<p>This instruction is designed to operate as a standard
3050 '<tt><a href="#i_call">call</a></tt>' instruction in most regards. The
3051 primary difference is that it establishes an association with a label, which
3052 is used by the runtime library to unwind the stack.</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3053
3054<p>This instruction is used in languages with destructors to ensure that proper
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3055 cleanup is performed in the case of either a <tt>longjmp</tt> or a thrown
3056 exception. Additionally, this is important for implementation of
3057 '<tt>catch</tt>' clauses in high-level languages that support them.</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3058
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3059<p>For the purposes of the SSA form, the definition of the value returned by the
3060 '<tt>invoke</tt>' instruction is deemed to occur on the edge from the current
3061 block to the "normal" label. If the callee unwinds then no return value is
3062 available.</p>
Dan Gohman9069d892009-05-22 21:47:08 +0000[diff] [blame]3063
Chris Lattner97257f82010-01-15 18:08:37 +0000[diff] [blame]3064<p>Note that the code generator does not yet completely support unwind, and
3065that the invoke/unwind semantics are likely to change in future versions.</p>
3066
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3067<h5>Example:</h5>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3068<pre>
Nick Lewycky084ab472008-03-16 07:18:12 +0000[diff] [blame]3069 %retval = invoke i32 @Test(i32 15) to label %Continue
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]3070 unwind label %TestCleanup <i>; {i32}:retval set</i>
Nick Lewycky084ab472008-03-16 07:18:12 +0000[diff] [blame]3071 %retval = invoke <a href="#callingconv">coldcc</a> i32 %Testfnptr(i32 15) to label %Continue
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]3072 unwind label %TestCleanup <i>; {i32}:retval set</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3073</pre>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3074
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3075</div>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3076
Chris Lattner5ed60612003-09-03 00:41:47 +0000[diff] [blame]3077<!-- _______________________________________________________________________ -->
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3078
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3079<div class="doc_subsubsection"> <a name="i_unwind">'<tt>unwind</tt>'
3080Instruction</a> </div>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3081
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3082<div class="doc_text">
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3083
Chris Lattner5ed60612003-09-03 00:41:47 +0000[diff] [blame]3084<h5>Syntax:</h5>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3085<pre>
3086 unwind
3087</pre>
3088
Chris Lattner5ed60612003-09-03 00:41:47 +0000[diff] [blame]3089<h5>Overview:</h5>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3090<p>The '<tt>unwind</tt>' instruction unwinds the stack, continuing control flow
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3091 at the first callee in the dynamic call stack which used
3092 an <a href="#i_invoke"><tt>invoke</tt></a> instruction to perform the call.
3093 This is primarily used to implement exception handling.</p>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3094
Chris Lattner5ed60612003-09-03 00:41:47 +0000[diff] [blame]3095<h5>Semantics:</h5>
Chris Lattnerfe8519c2008-04-19 21:01:16 +0000[diff] [blame]3096<p>The '<tt>unwind</tt>' instruction causes execution of the current function to
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3097 immediately halt. The dynamic call stack is then searched for the
3098 first <a href="#i_invoke"><tt>invoke</tt></a> instruction on the call stack.
3099 Once found, execution continues at the "exceptional" destination block
3100 specified by the <tt>invoke</tt> instruction. If there is no <tt>invoke</tt>
3101 instruction in the dynamic call chain, undefined behavior results.</p>
3102
Chris Lattner97257f82010-01-15 18:08:37 +0000[diff] [blame]3103<p>Note that the code generator does not yet completely support unwind, and
3104that the invoke/unwind semantics are likely to change in future versions.</p>
3105
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3106</div>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3107
3108<!-- _______________________________________________________________________ -->
3109
3110<div class="doc_subsubsection"> <a name="i_unreachable">'<tt>unreachable</tt>'
3111Instruction</a> </div>
3112
3113<div class="doc_text">
3114
3115<h5>Syntax:</h5>
3116<pre>
3117 unreachable
3118</pre>
3119
3120<h5>Overview:</h5>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3121<p>The '<tt>unreachable</tt>' instruction has no defined semantics. This
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3122 instruction is used to inform the optimizer that a particular portion of the
3123 code is not reachable. This can be used to indicate that the code after a
3124 no-return function cannot be reached, and other facts.</p>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3125
3126<h5>Semantics:</h5>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3127<p>The '<tt>unreachable</tt>' instruction has no defined semantics.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3128
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3129</div>
3130
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3131<!-- ======================================================================= -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3132<div class="doc_subsection"> <a name="binaryops">Binary Operations</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3133
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3134<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3135
3136<p>Binary operators are used to do most of the computation in a program. They
3137 require two operands of the same type, execute an operation on them, and
3138 produce a single value. The operands might represent multiple data, as is
3139 the case with the <a href="#t_vector">vector</a> data type. The result value
3140 has the same type as its operands.</p>
3141
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3142<p>There are several different binary operators:</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3143
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3144</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3145
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3146<!-- _______________________________________________________________________ -->
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3147<div class="doc_subsubsection">
3148 <a name="i_add">'<tt>add</tt>' Instruction</a>
3149</div>
3150
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3151<div class="doc_text">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3152
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3153<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3154<pre>
Dan Gohmanb07de442009-07-20 22:41:19 +0000[diff] [blame]3155 &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]3156 &lt;result&gt; = add nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3157 &lt;result&gt; = add nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3158 &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]3159</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3160
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3161<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3162<p>The '<tt>add</tt>' instruction returns the sum of its two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3163
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3164<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3165<p>The two arguments to the '<tt>add</tt>' instruction must
3166 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3167 integer values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3168
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3169<h5>Semantics:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3170<p>The value produced is the integer sum of the two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3171
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3172<p>If the sum has unsigned overflow, the result returned is the mathematical
3173 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]3174
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3175<p>Because LLVM integers use a two's complement representation, this instruction
3176 is appropriate for both signed and unsigned integers.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3177
Dan Gohman902dfff2009-07-22 22:44:56 +0000[diff] [blame]3178<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3179 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3180 <tt>nsw</tt> keywords are present, the result value of the <tt>add</tt>
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]3181 is a <a href="#trapvalues">trap value</a> if unsigned and/or signed overflow,
3182 respectively, occurs.</p>
Dan Gohmanb07de442009-07-20 22:41:19 +0000[diff] [blame]3183
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3184<h5>Example:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3185<pre>
3186 &lt;result&gt; = add i32 4, %var <i>; yields {i32}:result = 4 + %var</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3187</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3188
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3189</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3190
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3191<!-- _______________________________________________________________________ -->
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3192<div class="doc_subsubsection">
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3193 <a name="i_fadd">'<tt>fadd</tt>' Instruction</a>
3194</div>
3195
3196<div class="doc_text">
3197
3198<h5>Syntax:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3199<pre>
3200 &lt;result&gt; = fadd &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3201</pre>
3202
3203<h5>Overview:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3204<p>The '<tt>fadd</tt>' instruction returns the sum of its two operands.</p>
3205
3206<h5>Arguments:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3207<p>The two arguments to the '<tt>fadd</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3208 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3209 floating point values. Both arguments must have identical types.</p>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3210
3211<h5>Semantics:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3212<p>The value produced is the floating point sum of the two operands.</p>
3213
3214<h5>Example:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3215<pre>
3216 &lt;result&gt; = fadd float 4.0, %var <i>; yields {float}:result = 4.0 + %var</i>
3217</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3218
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3219</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3220
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3221<!-- _______________________________________________________________________ -->
3222<div class="doc_subsubsection">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3223 <a name="i_sub">'<tt>sub</tt>' Instruction</a>
3224</div>
3225
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3226<div class="doc_text">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3227
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3228<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3229<pre>
Dan Gohman902dfff2009-07-22 22:44:56 +0000[diff] [blame]3230 &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]3231 &lt;result&gt; = sub nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3232 &lt;result&gt; = sub nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3233 &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]3234</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3235
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3236<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3237<p>The '<tt>sub</tt>' instruction returns the difference of its two
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3238 operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3239
3240<p>Note that the '<tt>sub</tt>' instruction is used to represent the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3241 '<tt>neg</tt>' instruction present in most other intermediate
3242 representations.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3243
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3244<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3245<p>The two arguments to the '<tt>sub</tt>' instruction must
3246 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3247 integer values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3248
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3249<h5>Semantics:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3250<p>The value produced is the integer difference of the two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3251
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3252<p>If the difference has unsigned overflow, the result returned is the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3253 mathematical result modulo 2<sup>n</sup>, where n is the bit width of the
3254 result.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3255
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3256<p>Because LLVM integers use a two's complement representation, this instruction
3257 is appropriate for both signed and unsigned integers.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3258
Dan Gohman902dfff2009-07-22 22:44:56 +0000[diff] [blame]3259<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3260 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3261 <tt>nsw</tt> keywords are present, the result value of the <tt>sub</tt>
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]3262 is a <a href="#trapvalues">trap value</a> if unsigned and/or signed overflow,
3263 respectively, occurs.</p>
Dan Gohmanb07de442009-07-20 22:41:19 +0000[diff] [blame]3264
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3265<h5>Example:</h5>
Bill Wendling2d8b9a82007-05-29 09:42:13 +0000[diff] [blame]3266<pre>
3267 &lt;result&gt; = sub i32 4, %var <i>; yields {i32}:result = 4 - %var</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3268 &lt;result&gt; = sub i32 0, %val <i>; yields {i32}:result = -%var</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3269</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3270
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3271</div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3272
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3273<!-- _______________________________________________________________________ -->
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3274<div class="doc_subsubsection">
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3275 <a name="i_fsub">'<tt>fsub</tt>' Instruction</a>
3276</div>
3277
3278<div class="doc_text">
3279
3280<h5>Syntax:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3281<pre>
3282 &lt;result&gt; = fsub &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3283</pre>
3284
3285<h5>Overview:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3286<p>The '<tt>fsub</tt>' instruction returns the difference of its two
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3287 operands.</p>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3288
3289<p>Note that the '<tt>fsub</tt>' instruction is used to represent the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3290 '<tt>fneg</tt>' instruction present in most other intermediate
3291 representations.</p>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3292
3293<h5>Arguments:</h5>
Bill Wendling972b7202009-07-20 02:32:41 +0000[diff] [blame]3294<p>The two arguments to the '<tt>fsub</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3295 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3296 floating point values. Both arguments must have identical types.</p>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3297
3298<h5>Semantics:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3299<p>The value produced is the floating point difference of the two operands.</p>
3300
3301<h5>Example:</h5>
3302<pre>
3303 &lt;result&gt; = fsub float 4.0, %var <i>; yields {float}:result = 4.0 - %var</i>
3304 &lt;result&gt; = fsub float -0.0, %val <i>; yields {float}:result = -%var</i>
3305</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3306
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3307</div>
3308
3309<!-- _______________________________________________________________________ -->
3310<div class="doc_subsubsection">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3311 <a name="i_mul">'<tt>mul</tt>' Instruction</a>
3312</div>
3313
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3314<div class="doc_text">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3315
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3316<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3317<pre>
Dan Gohman902dfff2009-07-22 22:44:56 +0000[diff] [blame]3318 &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]3319 &lt;result&gt; = mul nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3320 &lt;result&gt; = mul nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3321 &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]3322</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3323
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3324<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3325<p>The '<tt>mul</tt>' instruction returns the product of its two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3326
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3327<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3328<p>The two arguments to the '<tt>mul</tt>' instruction must
3329 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3330 integer values. Both arguments must have identical types.</p>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3331
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3332<h5>Semantics:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3333<p>The value produced is the integer product of the two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3334
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3335<p>If the result of the multiplication has unsigned overflow, the result
3336 returned is the mathematical result modulo 2<sup>n</sup>, where n is the bit
3337 width of the result.</p>
3338
3339<p>Because LLVM integers use a two's complement representation, and the result
3340 is the same width as the operands, this instruction returns the correct
3341 result for both signed and unsigned integers. If a full product
3342 (e.g. <tt>i32</tt>x<tt>i32</tt>-><tt>i64</tt>) is needed, the operands should
3343 be sign-extended or zero-extended as appropriate to the width of the full
3344 product.</p>
3345
Dan Gohman902dfff2009-07-22 22:44:56 +0000[diff] [blame]3346<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3347 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3348 <tt>nsw</tt> keywords are present, the result value of the <tt>mul</tt>
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]3349 is a <a href="#trapvalues">trap value</a> if unsigned and/or signed overflow,
3350 respectively, occurs.</p>
Dan Gohmanb07de442009-07-20 22:41:19 +0000[diff] [blame]3351
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3352<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3353<pre>
3354 &lt;result&gt; = mul i32 4, %var <i>; yields {i32}:result = 4 * %var</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3355</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3356
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3357</div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3358
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3359<!-- _______________________________________________________________________ -->
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3360<div class="doc_subsubsection">
3361 <a name="i_fmul">'<tt>fmul</tt>' Instruction</a>
3362</div>
3363
3364<div class="doc_text">
3365
3366<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3367<pre>
3368 &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]3369</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3370
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3371<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3372<p>The '<tt>fmul</tt>' instruction returns the product of its two operands.</p>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3373
3374<h5>Arguments:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3375<p>The two arguments to the '<tt>fmul</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3376 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3377 floating point values. Both arguments must have identical types.</p>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3378
3379<h5>Semantics:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3380<p>The value produced is the floating point product of the two operands.</p>
3381
3382<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3383<pre>
3384 &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]3385</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3386
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3387</div>
3388
3389<!-- _______________________________________________________________________ -->
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3390<div class="doc_subsubsection"> <a name="i_udiv">'<tt>udiv</tt>' Instruction
3391</a></div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3392
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3393<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3394
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3395<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3396<pre>
3397 &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]3398</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3399
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3400<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3401<p>The '<tt>udiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3402
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3403<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3404<p>The two arguments to the '<tt>udiv</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3405 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3406 values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3407
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3408<h5>Semantics:</h5>
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3409<p>The value produced is the unsigned integer quotient of the two operands.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3410
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3411<p>Note that unsigned integer division and signed integer division are distinct
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3412 operations; for signed integer division, use '<tt>sdiv</tt>'.</p>
3413
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3414<p>Division by zero leads to undefined behavior.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3415
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3416<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3417<pre>
3418 &lt;result&gt; = udiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3419</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3420
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3421</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3422
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3423<!-- _______________________________________________________________________ -->
3424<div class="doc_subsubsection"> <a name="i_sdiv">'<tt>sdiv</tt>' Instruction
3425</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3426
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3427<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3428
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3429<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3430<pre>
Dan Gohmanb07de442009-07-20 22:41:19 +0000[diff] [blame]3431 &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]3432 &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]3433</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3434
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3435<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3436<p>The '<tt>sdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3437
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3438<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3439<p>The two arguments to the '<tt>sdiv</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3440 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3441 values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3442
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3443<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3444<p>The value produced is the signed integer quotient of the two operands rounded
3445 towards zero.</p>
3446
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3447<p>Note that signed integer division and unsigned integer division are distinct
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3448 operations; for unsigned integer division, use '<tt>udiv</tt>'.</p>
3449
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3450<p>Division by zero leads to undefined behavior. Overflow also leads to
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3451 undefined behavior; this is a rare case, but can occur, for example, by doing
3452 a 32-bit division of -2147483648 by -1.</p>
3453
Dan Gohman71dfd782009-07-22 00:04:19 +0000[diff] [blame]3454<p>If the <tt>exact</tt> keyword is present, the result value of the
Dan Gohman57255802010-04-23 15:23:32 +0000[diff] [blame]3455 <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]3456 be rounded.</p>
Dan Gohmanb07de442009-07-20 22:41:19 +0000[diff] [blame]3457
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3458<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3459<pre>
3460 &lt;result&gt; = sdiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3461</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3462
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3463</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3464
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3465<!-- _______________________________________________________________________ -->
3466<div class="doc_subsubsection"> <a name="i_fdiv">'<tt>fdiv</tt>'
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3467Instruction</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3468
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3469<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3470
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3471<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3472<pre>
Gabor Greif0f75ad02008-08-07 21:46:00 +0000[diff] [blame]3473 &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]3474</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3475
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3476<h5>Overview:</h5>
3477<p>The '<tt>fdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3478
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3479<h5>Arguments:</h5>
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]3480<p>The two arguments to the '<tt>fdiv</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3481 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3482 floating point values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3483
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3484<h5>Semantics:</h5>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3485<p>The value produced is the floating point quotient of the two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3486
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3487<h5>Example:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3488<pre>
3489 &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]3490</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3491
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3492</div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3493
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3494<!-- _______________________________________________________________________ -->
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3495<div class="doc_subsubsection"> <a name="i_urem">'<tt>urem</tt>' Instruction</a>
3496</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3497
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3498<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3499
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3500<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3501<pre>
3502 &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]3503</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3504
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3505<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3506<p>The '<tt>urem</tt>' instruction returns the remainder from the unsigned
3507 division of its two arguments.</p>
3508
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3509<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3510<p>The two arguments to the '<tt>urem</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3511 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3512 values. Both arguments must have identical types.</p>
3513
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3514<h5>Semantics:</h5>
3515<p>This instruction returns the unsigned integer <i>remainder</i> of a division.
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3516 This instruction always performs an unsigned division to get the
3517 remainder.</p>
3518
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3519<p>Note that unsigned integer remainder and signed integer remainder are
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3520 distinct operations; for signed integer remainder, use '<tt>srem</tt>'.</p>
3521
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3522<p>Taking the remainder of a division by zero leads to undefined behavior.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3523
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3524<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3525<pre>
3526 &lt;result&gt; = urem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3527</pre>
3528
3529</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3530
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3531<!-- _______________________________________________________________________ -->
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3532<div class="doc_subsubsection">
3533 <a name="i_srem">'<tt>srem</tt>' Instruction</a>
3534</div>
3535
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3536<div class="doc_text">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3537
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3538<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3539<pre>
Gabor Greif0f75ad02008-08-07 21:46:00 +0000[diff] [blame]3540 &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]3541</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3542
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3543<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3544<p>The '<tt>srem</tt>' instruction returns the remainder from the signed
3545 division of its two operands. This instruction can also take
3546 <a href="#t_vector">vector</a> versions of the values in which case the
3547 elements must be integers.</p>
Chris Lattnerb8f816e2008-01-04 04:33:49 +0000[diff] [blame]3548
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3549<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3550<p>The two arguments to the '<tt>srem</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3551 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3552 values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3553
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3554<h5>Semantics:</h5>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3555<p>This instruction returns the <i>remainder</i> of a division (where the result
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3556 has the same sign as the dividend, <tt>op1</tt>), not the <i>modulo</i>
3557 operator (where the result has the same sign as the divisor, <tt>op2</tt>) of
3558 a value. For more information about the difference,
3559 see <a href="http://mathforum.org/dr.math/problems/anne.4.28.99.html">The
3560 Math Forum</a>. For a table of how this is implemented in various languages,
3561 please see <a href="http://en.wikipedia.org/wiki/Modulo_operation">
3562 Wikipedia: modulo operation</a>.</p>
3563
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3564<p>Note that signed integer remainder and unsigned integer remainder are
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3565 distinct operations; for unsigned integer remainder, use '<tt>urem</tt>'.</p>
3566
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3567<p>Taking the remainder of a division by zero leads to undefined behavior.
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3568 Overflow also leads to undefined behavior; this is a rare case, but can
3569 occur, for example, by taking the remainder of a 32-bit division of
3570 -2147483648 by -1. (The remainder doesn't actually overflow, but this rule
3571 lets srem be implemented using instructions that return both the result of
3572 the division and the remainder.)</p>
3573
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3574<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3575<pre>
3576 &lt;result&gt; = srem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3577</pre>
3578
3579</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3580
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3581<!-- _______________________________________________________________________ -->
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3582<div class="doc_subsubsection">
3583 <a name="i_frem">'<tt>frem</tt>' Instruction</a> </div>
3584
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3585<div class="doc_text">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3586
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3587<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3588<pre>
3589 &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]3590</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3591
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3592<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3593<p>The '<tt>frem</tt>' instruction returns the remainder from the division of
3594 its two operands.</p>
3595
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3596<h5>Arguments:</h5>
3597<p>The two arguments to the '<tt>frem</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3598 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3599 floating point values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3600
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3601<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3602<p>This instruction returns the <i>remainder</i> of a division. The remainder
3603 has the same sign as the dividend.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3604
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3605<h5>Example:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3606<pre>
3607 &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]3608</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3609
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3610</div>
Robert Bocchino820bc75b2006-02-17 21:18:08 +0000[diff] [blame]3611
Reid Spencer2ab01932007-02-02 13:57:07 +0000[diff] [blame]3612<!-- ======================================================================= -->
3613<div class="doc_subsection"> <a name="bitwiseops">Bitwise Binary
3614Operations</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3615
Reid Spencer2ab01932007-02-02 13:57:07 +0000[diff] [blame]3616<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3617
3618<p>Bitwise binary operators are used to do various forms of bit-twiddling in a
3619 program. They are generally very efficient instructions and can commonly be
3620 strength reduced from other instructions. They require two operands of the
3621 same type, execute an operation on them, and produce a single value. The
3622 resulting value is the same type as its operands.</p>
3623
Reid Spencer2ab01932007-02-02 13:57:07 +0000[diff] [blame]3624</div>
3625
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3626<!-- _______________________________________________________________________ -->
3627<div class="doc_subsubsection"> <a name="i_shl">'<tt>shl</tt>'
3628Instruction</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3629
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3630<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3631
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3632<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3633<pre>
3634 &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]3635</pre>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]3636
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3637<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3638<p>The '<tt>shl</tt>' instruction returns the first operand shifted to the left
3639 a specified number of bits.</p>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]3640
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3641<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3642<p>Both arguments to the '<tt>shl</tt>' instruction must be the
3643 same <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3644 integer type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3645
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3646<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3647<p>The value produced is <tt>op1</tt> * 2<sup><tt>op2</tt></sup> mod
3648 2<sup>n</sup>, where <tt>n</tt> is the width of the result. If <tt>op2</tt>
3649 is (statically or dynamically) negative or equal to or larger than the number
3650 of bits in <tt>op1</tt>, the result is undefined. If the arguments are
3651 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
3652 shift amount in <tt>op2</tt>.</p>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]3653
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3654<h5>Example:</h5>
3655<pre>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3656 &lt;result&gt; = shl i32 4, %var <i>; yields {i32}: 4 &lt;&lt; %var</i>
3657 &lt;result&gt; = shl i32 4, 2 <i>; yields {i32}: 16</i>
3658 &lt;result&gt; = shl i32 1, 10 <i>; yields {i32}: 1024</i>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]3659 &lt;result&gt; = shl i32 1, 32 <i>; undefined</i>
Mon P Wang4dd832d2008-12-09 05:46:39 +0000[diff] [blame]3660 &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]3661</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3662
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3663</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3664
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3665<!-- _______________________________________________________________________ -->
3666<div class="doc_subsubsection"> <a name="i_lshr">'<tt>lshr</tt>'
3667Instruction</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3668
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3669<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3670
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3671<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3672<pre>
3673 &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]3674</pre>
3675
3676<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3677<p>The '<tt>lshr</tt>' instruction (logical shift right) returns the first
3678 operand shifted to the right a specified number of bits with zero fill.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3679
3680<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3681<p>Both arguments to the '<tt>lshr</tt>' instruction must be the same
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3682 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3683 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3684
3685<h5>Semantics:</h5>
3686<p>This instruction always performs a logical shift right operation. The most
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3687 significant bits of the result will be filled with zero bits after the shift.
3688 If <tt>op2</tt> is (statically or dynamically) equal to or larger than the
3689 number of bits in <tt>op1</tt>, the result is undefined. If the arguments are
3690 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
3691 shift amount in <tt>op2</tt>.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3692
3693<h5>Example:</h5>
3694<pre>
3695 &lt;result&gt; = lshr i32 4, 1 <i>; yields {i32}:result = 2</i>
3696 &lt;result&gt; = lshr i32 4, 2 <i>; yields {i32}:result = 1</i>
3697 &lt;result&gt; = lshr i8 4, 3 <i>; yields {i8}:result = 0</i>
3698 &lt;result&gt; = lshr i8 -2, 1 <i>; yields {i8}:result = 0x7FFFFFFF </i>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]3699 &lt;result&gt; = lshr i32 1, 32 <i>; undefined</i>
Mon P Wang4dd832d2008-12-09 05:46:39 +0000[diff] [blame]3700 &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]3701</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3702
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3703</div>
3704
Reid Spencer2ab01932007-02-02 13:57:07 +0000[diff] [blame]3705<!-- _______________________________________________________________________ -->
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3706<div class="doc_subsubsection"> <a name="i_ashr">'<tt>ashr</tt>'
3707Instruction</a> </div>
3708<div class="doc_text">
3709
3710<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3711<pre>
3712 &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]3713</pre>
3714
3715<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3716<p>The '<tt>ashr</tt>' instruction (arithmetic shift right) returns the first
3717 operand shifted to the right a specified number of bits with sign
3718 extension.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3719
3720<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3721<p>Both arguments to the '<tt>ashr</tt>' instruction must be the same
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3722 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3723 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3724
3725<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3726<p>This instruction always performs an arithmetic shift right operation, The
3727 most significant bits of the result will be filled with the sign bit
3728 of <tt>op1</tt>. If <tt>op2</tt> is (statically or dynamically) equal to or
3729 larger than the number of bits in <tt>op1</tt>, the result is undefined. If
3730 the arguments are vectors, each vector element of <tt>op1</tt> is shifted by
3731 the corresponding shift amount in <tt>op2</tt>.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3732
3733<h5>Example:</h5>
3734<pre>
3735 &lt;result&gt; = ashr i32 4, 1 <i>; yields {i32}:result = 2</i>
3736 &lt;result&gt; = ashr i32 4, 2 <i>; yields {i32}:result = 1</i>
3737 &lt;result&gt; = ashr i8 4, 3 <i>; yields {i8}:result = 0</i>
3738 &lt;result&gt; = ashr i8 -2, 1 <i>; yields {i8}:result = -1</i>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]3739 &lt;result&gt; = ashr i32 1, 32 <i>; undefined</i>
Mon P Wang4dd832d2008-12-09 05:46:39 +0000[diff] [blame]3740 &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]3741</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3742
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3743</div>
3744
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3745<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3746<div class="doc_subsubsection"> <a name="i_and">'<tt>and</tt>'
3747Instruction</a> </div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3748
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3749<div class="doc_text">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3750
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3751<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3752<pre>
Gabor Greif0f75ad02008-08-07 21:46:00 +0000[diff] [blame]3753 &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]3754</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3755
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3756<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3757<p>The '<tt>and</tt>' instruction returns the bitwise logical and of its two
3758 operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3759
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3760<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3761<p>The two arguments to the '<tt>and</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3762 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3763 values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3764
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3765<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3766<p>The truth table used for the '<tt>and</tt>' instruction is:</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3767
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3768<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3769 <tbody>
3770 <tr>
3771 <td>In0</td>
3772 <td>In1</td>
3773 <td>Out</td>
3774 </tr>
3775 <tr>
3776 <td>0</td>
3777 <td>0</td>
3778 <td>0</td>
3779 </tr>
3780 <tr>
3781 <td>0</td>
3782 <td>1</td>
3783 <td>0</td>
3784 </tr>
3785 <tr>
3786 <td>1</td>
3787 <td>0</td>
3788 <td>0</td>
3789 </tr>
3790 <tr>
3791 <td>1</td>
3792 <td>1</td>
3793 <td>1</td>
3794 </tr>
3795 </tbody>
3796</table>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3797
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3798<h5>Example:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3799<pre>
3800 &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]3801 &lt;result&gt; = and i32 15, 40 <i>; yields {i32}:result = 8</i>
3802 &lt;result&gt; = and i32 4, 8 <i>; yields {i32}:result = 0</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3803</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3804</div>
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_or">'<tt>or</tt>' Instruction</a> </div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3807
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3808<div class="doc_text">
3809
3810<h5>Syntax:</h5>
3811<pre>
3812 &lt;result&gt; = or &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3813</pre>
3814
3815<h5>Overview:</h5>
3816<p>The '<tt>or</tt>' instruction returns the bitwise logical inclusive or of its
3817 two operands.</p>
3818
3819<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3820<p>The two arguments to the '<tt>or</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3821 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3822 values. Both arguments must have identical types.</p>
3823
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3824<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3825<p>The truth table used for the '<tt>or</tt>' instruction is:</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3826
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3827<table border="1" cellspacing="0" cellpadding="4">
3828 <tbody>
3829 <tr>
3830 <td>In0</td>
3831 <td>In1</td>
3832 <td>Out</td>
3833 </tr>
3834 <tr>
3835 <td>0</td>
3836 <td>0</td>
3837 <td>0</td>
3838 </tr>
3839 <tr>
3840 <td>0</td>
3841 <td>1</td>
3842 <td>1</td>
3843 </tr>
3844 <tr>
3845 <td>1</td>
3846 <td>0</td>
3847 <td>1</td>
3848 </tr>
3849 <tr>
3850 <td>1</td>
3851 <td>1</td>
3852 <td>1</td>
3853 </tr>
3854 </tbody>
3855</table>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3856
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3857<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3858<pre>
3859 &lt;result&gt; = or i32 4, %var <i>; yields {i32}:result = 4 | %var</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3860 &lt;result&gt; = or i32 15, 40 <i>; yields {i32}:result = 47</i>
3861 &lt;result&gt; = or i32 4, 8 <i>; yields {i32}:result = 12</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3862</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3863
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3864</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3865
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3866<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3867<div class="doc_subsubsection"> <a name="i_xor">'<tt>xor</tt>'
3868Instruction</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3869
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3870<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3871
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3872<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3873<pre>
3874 &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]3875</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3876
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3877<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3878<p>The '<tt>xor</tt>' instruction returns the bitwise logical exclusive or of
3879 its two operands. The <tt>xor</tt> is used to implement the "one's
3880 complement" operation, which is the "~" operator in C.</p>
3881
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3882<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3883<p>The two arguments to the '<tt>xor</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3884 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3885 values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3886
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3887<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3888<p>The truth table used for the '<tt>xor</tt>' instruction is:</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3889
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3890<table border="1" cellspacing="0" cellpadding="4">
3891 <tbody>
3892 <tr>
3893 <td>In0</td>
3894 <td>In1</td>
3895 <td>Out</td>
3896 </tr>
3897 <tr>
3898 <td>0</td>
3899 <td>0</td>
3900 <td>0</td>
3901 </tr>
3902 <tr>
3903 <td>0</td>
3904 <td>1</td>
3905 <td>1</td>
3906 </tr>
3907 <tr>
3908 <td>1</td>
3909 <td>0</td>
3910 <td>1</td>
3911 </tr>
3912 <tr>
3913 <td>1</td>
3914 <td>1</td>
3915 <td>0</td>
3916 </tr>
3917 </tbody>
3918</table>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3919
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3920<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3921<pre>
3922 &lt;result&gt; = xor i32 4, %var <i>; yields {i32}:result = 4 ^ %var</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3923 &lt;result&gt; = xor i32 15, 40 <i>; yields {i32}:result = 39</i>
3924 &lt;result&gt; = xor i32 4, 8 <i>; yields {i32}:result = 12</i>
3925 &lt;result&gt; = xor i32 %V, -1 <i>; yields {i32}:result = ~%V</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3926</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3927
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3928</div>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3929
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3930<!-- ======================================================================= -->
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3931<div class="doc_subsection">
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]3932 <a name="vectorops">Vector Operations</a>
3933</div>
3934
3935<div class="doc_text">
3936
3937<p>LLVM supports several instructions to represent vector operations in a
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3938 target-independent manner. These instructions cover the element-access and
3939 vector-specific operations needed to process vectors effectively. While LLVM
3940 does directly support these vector operations, many sophisticated algorithms
3941 will want to use target-specific intrinsics to take full advantage of a
3942 specific target.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]3943
3944</div>
3945
3946<!-- _______________________________________________________________________ -->
3947<div class="doc_subsubsection">
3948 <a name="i_extractelement">'<tt>extractelement</tt>' Instruction</a>
3949</div>
3950
3951<div class="doc_text">
3952
3953<h5>Syntax:</h5>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]3954<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3955 &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]3956</pre>
3957
3958<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3959<p>The '<tt>extractelement</tt>' instruction extracts a single scalar element
3960 from a vector at a specified index.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]3961
3962
3963<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3964<p>The first operand of an '<tt>extractelement</tt>' instruction is a value
3965 of <a href="#t_vector">vector</a> type. The second operand is an index
3966 indicating the position from which to extract the element. The index may be
3967 a variable.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]3968
3969<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3970<p>The result is a scalar of the same type as the element type of
3971 <tt>val</tt>. Its value is the value at position <tt>idx</tt> of
3972 <tt>val</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
3973 results are undefined.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]3974
3975<h5>Example:</h5>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]3976<pre>
Gabor Greif03ab4dc2009-10-28 13:14:50 +0000[diff] [blame]3977 &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]3978</pre>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]3979
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3980</div>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]3981
3982<!-- _______________________________________________________________________ -->
3983<div class="doc_subsubsection">
3984 <a name="i_insertelement">'<tt>insertelement</tt>' Instruction</a>
3985</div>
3986
3987<div class="doc_text">
3988
3989<h5>Syntax:</h5>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]3990<pre>
Dan Gohman43ba0672008-05-12 23:38:42 +0000[diff] [blame]3991 &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]3992</pre>
3993
3994<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3995<p>The '<tt>insertelement</tt>' instruction inserts a scalar element into a
3996 vector at a specified index.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]3997
3998<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3999<p>The first operand of an '<tt>insertelement</tt>' instruction is a value
4000 of <a href="#t_vector">vector</a> type. The second operand is a scalar value
4001 whose type must equal the element type of the first operand. The third
4002 operand is an index indicating the position at which to insert the value.
4003 The index may be a variable.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4004
4005<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4006<p>The result is a vector of the same type as <tt>val</tt>. Its element values
4007 are those of <tt>val</tt> except at position <tt>idx</tt>, where it gets the
4008 value <tt>elt</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
4009 results are undefined.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4010
4011<h5>Example:</h5>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4012<pre>
Gabor Greif03ab4dc2009-10-28 13:14:50 +0000[diff] [blame]4013 &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]4014</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4015
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4016</div>
4017
4018<!-- _______________________________________________________________________ -->
4019<div class="doc_subsubsection">
4020 <a name="i_shufflevector">'<tt>shufflevector</tt>' Instruction</a>
4021</div>
4022
4023<div class="doc_text">
4024
4025<h5>Syntax:</h5>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4026<pre>
Mon P Wang25f01062008-11-10 04:46:22 +0000[diff] [blame]4027 &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]4028</pre>
4029
4030<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4031<p>The '<tt>shufflevector</tt>' instruction constructs a permutation of elements
4032 from two input vectors, returning a vector with the same element type as the
4033 input and length that is the same as the shuffle mask.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4034
4035<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4036<p>The first two operands of a '<tt>shufflevector</tt>' instruction are vectors
4037 with types that match each other. The third argument is a shuffle mask whose
4038 element type is always 'i32'. The result of the instruction is a vector
4039 whose length is the same as the shuffle mask and whose element type is the
4040 same as the element type of the first two operands.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4041
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4042<p>The shuffle mask operand is required to be a constant vector with either
4043 constant integer or undef values.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4044
4045<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4046<p>The elements of the two input vectors are numbered from left to right across
4047 both of the vectors. The shuffle mask operand specifies, for each element of
4048 the result vector, which element of the two input vectors the result element
4049 gets. The element selector may be undef (meaning "don't care") and the
4050 second operand may be undef if performing a shuffle from only one vector.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4051
4052<h5>Example:</h5>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4053<pre>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4054 &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]4055 &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]4056 &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]4057 &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]4058 &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]4059 &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]4060 &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]4061 &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]4062</pre>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4063
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4064</div>
Tanya Lattnerb138bbe2006-04-14 19:24:33 +0000[diff] [blame]4065
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4066<!-- ======================================================================= -->
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4067<div class="doc_subsection">
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4068 <a name="aggregateops">Aggregate Operations</a>
4069</div>
4070
4071<div class="doc_text">
4072
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]4073<p>LLVM supports several instructions for working with
4074 <a href="#t_aggregate">aggregate</a> values.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4075
4076</div>
4077
4078<!-- _______________________________________________________________________ -->
4079<div class="doc_subsubsection">
4080 <a name="i_extractvalue">'<tt>extractvalue</tt>' Instruction</a>
4081</div>
4082
4083<div class="doc_text">
4084
4085<h5>Syntax:</h5>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4086<pre>
4087 &lt;result&gt; = extractvalue &lt;aggregate type&gt; &lt;val&gt;, &lt;idx&gt;{, &lt;idx&gt;}*
4088</pre>
4089
4090<h5>Overview:</h5>
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]4091<p>The '<tt>extractvalue</tt>' instruction extracts the value of a member field
4092 from an <a href="#t_aggregate">aggregate</a> value.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4093
4094<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4095<p>The first operand of an '<tt>extractvalue</tt>' instruction is a value
Chris Lattner13ee7952010-08-28 04:09:24 +0000[diff] [blame^]4096 of <a href="#t_struct">struct</a> or
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]4097 <a href="#t_array">array</a> type. The operands are constant indices to
4098 specify which value to extract in a similar manner as indices in a
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4099 '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4100
4101<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4102<p>The result is the value at the position in the aggregate specified by the
4103 index operands.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4104
4105<h5>Example:</h5>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4106<pre>
Gabor Greif03ab4dc2009-10-28 13:14:50 +0000[diff] [blame]4107 &lt;result&gt; = extractvalue {i32, float} %agg, 0 <i>; yields i32</i>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4108</pre>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4109
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4110</div>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4111
4112<!-- _______________________________________________________________________ -->
4113<div class="doc_subsubsection">
4114 <a name="i_insertvalue">'<tt>insertvalue</tt>' Instruction</a>
4115</div>
4116
4117<div class="doc_text">
4118
4119<h5>Syntax:</h5>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4120<pre>
Jeffrey Yasskinf991bbb2010-01-11 19:19:26 +0000[diff] [blame]4121 &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]4122</pre>
4123
4124<h5>Overview:</h5>
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]4125<p>The '<tt>insertvalue</tt>' instruction inserts a value into a member field
4126 in an <a href="#t_aggregate">aggregate</a> value.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4127
4128<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4129<p>The first operand of an '<tt>insertvalue</tt>' instruction is a value
Chris Lattner13ee7952010-08-28 04:09:24 +0000[diff] [blame^]4130 of <a href="#t_struct">struct</a> or
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]4131 <a href="#t_array">array</a> type. The second operand is a first-class
4132 value to insert. The following operands are constant indices indicating
4133 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]4134 '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction. The
4135 value to insert must have the same type as the value identified by the
4136 indices.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4137
4138<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4139<p>The result is an aggregate of the same type as <tt>val</tt>. Its value is
4140 that of <tt>val</tt> except that the value at the position specified by the
4141 indices is that of <tt>elt</tt>.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4142
4143<h5>Example:</h5>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4144<pre>
Jeffrey Yasskinf991bbb2010-01-11 19:19:26 +0000[diff] [blame]4145 %agg1 = insertvalue {i32, float} undef, i32 1, 0 <i>; yields {i32 1, float undef}</i>
4146 %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]4147</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4148
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4149</div>
4150
4151
4152<!-- ======================================================================= -->
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4153<div class="doc_subsection">
Chris Lattner6ab66722006-08-15 00:45:58 +0000[diff] [blame]4154 <a name="memoryops">Memory Access and Addressing Operations</a>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4155</div>
4156
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4157<div class="doc_text">
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4158
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4159<p>A key design point of an SSA-based representation is how it represents
4160 memory. In LLVM, no memory locations are in SSA form, which makes things
Victor Hernandeza70c6df2009-10-26 23:44:29 +0000[diff] [blame]4161 very simple. This section describes how to read, write, and allocate
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4162 memory in LLVM.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4163
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4164</div>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4165
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4166<!-- _______________________________________________________________________ -->
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4167<div class="doc_subsubsection">
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4168 <a name="i_alloca">'<tt>alloca</tt>' Instruction</a>
4169</div>
4170
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4171<div class="doc_text">
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4172
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4173<h5>Syntax:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4174<pre>
Dan Gohman2140a742010-05-28 01:14:11 +0000[diff] [blame]4175 &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]4176</pre>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4177
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4178<h5>Overview:</h5>
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]4179<p>The '<tt>alloca</tt>' instruction allocates memory on the stack frame of the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4180 currently executing function, to be automatically released when this function
4181 returns to its caller. The object is always allocated in the generic address
4182 space (address space zero).</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4183
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4184<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4185<p>The '<tt>alloca</tt>' instruction
4186 allocates <tt>sizeof(&lt;type&gt;)*NumElements</tt> bytes of memory on the
4187 runtime stack, returning a pointer of the appropriate type to the program.
4188 If "NumElements" is specified, it is the number of elements allocated,
4189 otherwise "NumElements" is defaulted to be one. If a constant alignment is
4190 specified, the value result of the allocation is guaranteed to be aligned to
4191 at least that boundary. If not specified, or if zero, the target can choose
4192 to align the allocation on any convenient boundary compatible with the
4193 type.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4194
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4195<p>'<tt>type</tt>' may be any sized type.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4196
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4197<h5>Semantics:</h5>
Bill Wendling9ee6a312009-05-08 20:49:29 +0000[diff] [blame]4198<p>Memory is allocated; a pointer is returned. The operation is undefined if
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4199 there is insufficient stack space for the allocation. '<tt>alloca</tt>'d
4200 memory is automatically released when the function returns. The
4201 '<tt>alloca</tt>' instruction is commonly used to represent automatic
4202 variables that must have an address available. When the function returns
4203 (either with the <tt><a href="#i_ret">ret</a></tt>
4204 or <tt><a href="#i_unwind">unwind</a></tt> instructions), the memory is
4205 reclaimed. Allocating zero bytes is legal, but the result is undefined.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4206
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4207<h5>Example:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4208<pre>
Dan Gohman7a5acb52009-01-04 23:49:44 +0000[diff] [blame]4209 %ptr = alloca i32 <i>; yields {i32*}:ptr</i>
4210 %ptr = alloca i32, i32 4 <i>; yields {i32*}:ptr</i>
4211 %ptr = alloca i32, i32 4, align 1024 <i>; yields {i32*}:ptr</i>
4212 %ptr = alloca i32, align 1024 <i>; yields {i32*}:ptr</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4213</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4214
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4215</div>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4216
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4217<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]4218<div class="doc_subsubsection"> <a name="i_load">'<tt>load</tt>'
4219Instruction</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4220
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4221<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4222
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4223<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4224<pre>
Bill Wendlingbc4024f2010-02-25 21:23:24 +0000[diff] [blame]4225 &lt;result&gt; = load &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;][, !nontemporal !&lt;index&gt;]
4226 &lt;result&gt; = volatile load &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;][, !nontemporal !&lt;index&gt;]
4227 !&lt;index&gt; = !{ i32 1 }
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4228</pre>
4229
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4230<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4231<p>The '<tt>load</tt>' instruction is used to read from memory.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4232
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4233<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4234<p>The argument to the '<tt>load</tt>' instruction specifies the memory address
4235 from which to load. The pointer must point to
4236 a <a href="#t_firstclass">first class</a> type. If the <tt>load</tt> is
4237 marked as <tt>volatile</tt>, then the optimizer is not allowed to modify the
Jeffrey Yasskin5d284ae2010-04-26 21:21:24 +0000[diff] [blame]4238 number or order of execution of this <tt>load</tt> with other <a
4239 href="#volatile">volatile operations</a>.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4240
Bill Wendlingbc4024f2010-02-25 21:23:24 +0000[diff] [blame]4241<p>The optional constant <tt>align</tt> argument specifies the alignment of the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4242 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]4243 omitted <tt>align</tt> argument means that the operation has the preferential
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4244 alignment for the target. It is the responsibility of the code emitter to
4245 ensure that the alignment information is correct. Overestimating the
Bill Wendlingbc4024f2010-02-25 21:23:24 +0000[diff] [blame]4246 alignment results in undefined behavior. Underestimating the alignment may
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4247 produce less efficient code. An alignment of 1 is always safe.</p>
4248
Bill Wendlingbc4024f2010-02-25 21:23:24 +0000[diff] [blame]4249<p>The optional <tt>!nontemporal</tt> metadata must reference a single
4250 metatadata name &lt;index&gt; corresponding to a metadata node with
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]4251 one <tt>i32</tt> entry of value 1. The existence of
Bill Wendlingbc4024f2010-02-25 21:23:24 +0000[diff] [blame]4252 the <tt>!nontemporal</tt> metatadata on the instruction tells the optimizer
4253 and code generator that this load is not expected to be reused in the cache.
4254 The code generator may select special instructions to save cache bandwidth,
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]4255 such as the <tt>MOVNT</tt> instruction on x86.</p>
David Greene9641d062010-02-16 20:50:18 +0000[diff] [blame]4256
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4257<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4258<p>The location of memory pointed to is loaded. If the value being loaded is of
4259 scalar type then the number of bytes read does not exceed the minimum number
4260 of bytes needed to hold all bits of the type. For example, loading an
4261 <tt>i24</tt> reads at most three bytes. When loading a value of a type like
4262 <tt>i20</tt> with a size that is not an integral number of bytes, the result
4263 is undefined if the value was not originally written using a store of the
4264 same type.</p>
4265
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4266<h5>Examples:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4267<pre>
4268 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
4269 <a href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4270 %val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4271</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4272
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4273</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4274
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4275<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]4276<div class="doc_subsubsection"> <a name="i_store">'<tt>store</tt>'
4277Instruction</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4278
Reid Spencera89fb182006-11-09 21:18:01 +0000[diff] [blame]4279<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4280
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4281<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4282<pre>
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]4283 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>
4284 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]4285</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4286
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4287<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4288<p>The '<tt>store</tt>' instruction is used to write to memory.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4289
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4290<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4291<p>There are two arguments to the '<tt>store</tt>' instruction: a value to store
4292 and an address at which to store it. The type of the
4293 '<tt>&lt;pointer&gt;</tt>' operand must be a pointer to
4294 the <a href="#t_firstclass">first class</a> type of the
Jeffrey Yasskin5d284ae2010-04-26 21:21:24 +0000[diff] [blame]4295 '<tt>&lt;value&gt;</tt>' operand. If the <tt>store</tt> is marked as
4296 <tt>volatile</tt>, then the optimizer is not allowed to modify the number or
4297 order of execution of this <tt>store</tt> with other <a
4298 href="#volatile">volatile operations</a>.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4299
4300<p>The optional constant "align" argument specifies the alignment of the
4301 operation (that is, the alignment of the memory address). A value of 0 or an
4302 omitted "align" argument means that the operation has the preferential
4303 alignment for the target. It is the responsibility of the code emitter to
4304 ensure that the alignment information is correct. Overestimating the
4305 alignment results in an undefined behavior. Underestimating the alignment may
4306 produce less efficient code. An alignment of 1 is always safe.</p>
4307
David Greene9641d062010-02-16 20:50:18 +0000[diff] [blame]4308<p>The optional !nontemporal metadata must reference a single metatadata
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]4309 name &lt;index&gt; corresponding to a metadata node with one i32 entry of
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]4310 value 1. The existence of the !nontemporal metatadata on the
David Greene9641d062010-02-16 20:50:18 +0000[diff] [blame]4311 instruction tells the optimizer and code generator that this load is
4312 not expected to be reused in the cache. The code generator may
4313 select special instructions to save cache bandwidth, such as the
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]4314 MOVNT instruction on x86.</p>
David Greene9641d062010-02-16 20:50:18 +0000[diff] [blame]4315
4316
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]4317<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4318<p>The contents of memory are updated to contain '<tt>&lt;value&gt;</tt>' at the
4319 location specified by the '<tt>&lt;pointer&gt;</tt>' operand. If
4320 '<tt>&lt;value&gt;</tt>' is of scalar type then the number of bytes written
4321 does not exceed the minimum number of bytes needed to hold all bits of the
4322 type. For example, storing an <tt>i24</tt> writes at most three bytes. When
4323 writing a value of a type like <tt>i20</tt> with a size that is not an
4324 integral number of bytes, it is unspecified what happens to the extra bits
4325 that do not belong to the type, but they will typically be overwritten.</p>
4326
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4327<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4328<pre>
4329 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Bill Wendling8830ffe2007-10-22 05:10:05 +0000[diff] [blame]4330 store i32 3, i32* %ptr <i>; yields {void}</i>
4331 %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]4332</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4333
Reid Spencer443460a2006-11-09 21:15:49 +0000[diff] [blame]4334</div>
4335
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4336<!-- _______________________________________________________________________ -->
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4337<div class="doc_subsubsection">
4338 <a name="i_getelementptr">'<tt>getelementptr</tt>' Instruction</a>
4339</div>
4340
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4341<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4342
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]4343<h5>Syntax:</h5>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4344<pre>
Matthijs Kooijman0e268272008-10-13 13:44:15 +0000[diff] [blame]4345 &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]4346 &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]4347</pre>
4348
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]4349<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4350<p>The '<tt>getelementptr</tt>' instruction is used to get the address of a
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]4351 subelement of an <a href="#t_aggregate">aggregate</a> data structure.
4352 It performs address calculation only and does not access memory.</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4353
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]4354<h5>Arguments:</h5>
Matthijs Kooijman0e268272008-10-13 13:44:15 +0000[diff] [blame]4355<p>The first argument is always a pointer, and forms the basis of the
Chris Lattnera40b9122009-07-29 06:44:13 +0000[diff] [blame]4356 calculation. The remaining arguments are indices that indicate which of the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4357 elements of the aggregate object are indexed. The interpretation of each
4358 index is dependent on the type being indexed into. The first index always
4359 indexes the pointer value given as the first argument, the second index
4360 indexes a value of the type pointed to (not necessarily the value directly
4361 pointed to, since the first index can be non-zero), etc. The first type
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]4362 indexed into must be a pointer value, subsequent types can be arrays,
Chris Lattner13ee7952010-08-28 04:09:24 +0000[diff] [blame^]4363 vectors, and structs. Note that subsequent types being indexed into
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]4364 can never be pointers, since that would require loading the pointer before
4365 continuing calculation.</p>
Matthijs Kooijman0e268272008-10-13 13:44:15 +0000[diff] [blame]4366
4367<p>The type of each index argument depends on the type it is indexing into.
Chris Lattner13ee7952010-08-28 04:09:24 +0000[diff] [blame^]4368 When indexing into a (optionally packed) structure, only <tt>i32</tt>
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]4369 integer <b>constants</b> are allowed. When indexing into an array, pointer
4370 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]4371 constant.</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4372
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4373<p>For example, let's consider a C code fragment and how it gets compiled to
4374 LLVM:</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4375
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]4376<pre class="doc_code">
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]4377struct RT {
4378 char A;
Chris Lattnera446f1b2007-05-29 15:43:56 +0000[diff] [blame]4379 int B[10][20];
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]4380 char C;
4381};
4382struct ST {
Chris Lattnera446f1b2007-05-29 15:43:56 +0000[diff] [blame]4383 int X;
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]4384 double Y;
4385 struct RT Z;
4386};
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4387
Chris Lattnera446f1b2007-05-29 15:43:56 +0000[diff] [blame]4388int *foo(struct ST *s) {
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]4389 return &amp;s[1].Z.B[5][13];
4390}
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4391</pre>
4392
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4393<p>The LLVM code generated by the GCC frontend is:</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4394
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]4395<pre class="doc_code">
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]4396%RT = <a href="#namedtypes">type</a> { i8 , [10 x [20 x i32]], i8 }
4397%ST = <a href="#namedtypes">type</a> { i32, double, %RT }
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4398
Dan Gohman6b867702009-07-25 02:23:48 +0000[diff] [blame]4399define i32* @foo(%ST* %s) {
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]4400entry:
4401 %reg = getelementptr %ST* %s, i32 1, i32 2, i32 1, i32 5, i32 13
4402 ret i32* %reg
4403}
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4404</pre>
4405
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]4406<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4407<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]4408 type, which is a pointer, yielding a '<tt>%ST</tt>' = '<tt>{ i32, double, %RT
4409 }</tt>' type, a structure. The second index indexes into the third element
4410 of the structure, yielding a '<tt>%RT</tt>' = '<tt>{ i8 , [10 x [20 x i32]],
4411 i8 }</tt>' type, another structure. The third index indexes into the second
4412 element of the structure, yielding a '<tt>[10 x [20 x i32]]</tt>' type, an
4413 array. The two dimensions of the array are subscripted into, yielding an
4414 '<tt>i32</tt>' type. The '<tt>getelementptr</tt>' instruction returns a
4415 pointer to this element, thus computing a value of '<tt>i32*</tt>' type.</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4416
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4417<p>Note that it is perfectly legal to index partially through a structure,
4418 returning a pointer to an inner element. Because of this, the LLVM code for
4419 the given testcase is equivalent to:</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4420
4421<pre>
Dan Gohman6b867702009-07-25 02:23:48 +0000[diff] [blame]4422 define i32* @foo(%ST* %s) {
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4423 %t1 = getelementptr %ST* %s, i32 1 <i>; yields %ST*:%t1</i>
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]4424 %t2 = getelementptr %ST* %t1, i32 0, i32 2 <i>; yields %RT*:%t2</i>
4425 %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]4426 %t4 = getelementptr [10 x [20 x i32]]* %t3, i32 0, i32 5 <i>; yields [20 x i32]*:%t4</i>
4427 %t5 = getelementptr [20 x i32]* %t4, i32 0, i32 13 <i>; yields i32*:%t5</i>
4428 ret i32* %t5
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4429 }
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]4430</pre>
Chris Lattnerc0ad71e2005-06-24 17:22:57 +0000[diff] [blame]4431
Dan Gohman1639c392009-07-27 21:53:46 +0000[diff] [blame]4432<p>If the <tt>inbounds</tt> keyword is present, the result value of the
Dan Gohman57255802010-04-23 15:23:32 +0000[diff] [blame]4433 <tt>getelementptr</tt> is a <a href="#trapvalues">trap value</a> if the
4434 base pointer is not an <i>in bounds</i> address of an allocated object,
4435 or if any of the addresses that would be formed by successive addition of
4436 the offsets implied by the indices to the base address with infinitely
4437 precise arithmetic are not an <i>in bounds</i> address of that allocated
4438 object. The <i>in bounds</i> addresses for an allocated object are all
4439 the addresses that point into the object, plus the address one byte past
4440 the end.</p>
Dan Gohman1639c392009-07-27 21:53:46 +0000[diff] [blame]4441
4442<p>If the <tt>inbounds</tt> keyword is not present, the offsets are added to
4443 the base address with silently-wrapping two's complement arithmetic, and
4444 the result value of the <tt>getelementptr</tt> may be outside the object
4445 pointed to by the base pointer. The result value may not necessarily be
4446 used to access memory though, even if it happens to point into allocated
4447 storage. See the <a href="#pointeraliasing">Pointer Aliasing Rules</a>
4448 section for more information.</p>
4449
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4450<p>The getelementptr instruction is often confusing. For some more insight into
4451 how it works, see <a href="GetElementPtr.html">the getelementptr FAQ</a>.</p>
Chris Lattner6ab66722006-08-15 00:45:58 +0000[diff] [blame]4452
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]4453<h5>Example:</h5>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4454<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4455 <i>; yields [12 x i8]*:aptr</i>
Matthijs Kooijman0e268272008-10-13 13:44:15 +0000[diff] [blame]4456 %aptr = getelementptr {i32, [12 x i8]}* %saptr, i64 0, i32 1
4457 <i>; yields i8*:vptr</i>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]4458 %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]4459 <i>; yields i8*:eptr</i>
4460 %eptr = getelementptr [12 x i8]* %aptr, i64 0, i32 1
Sanjiv Gupta0c155e62009-04-25 07:27:44 +0000[diff] [blame]4461 <i>; yields i32*:iptr</i>
Sanjiv Gupta77abea02009-04-24 16:38:13 +0000[diff] [blame]4462 %iptr = getelementptr [10 x i32]* @arr, i16 0, i16 0
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4463</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4464
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4465</div>
Reid Spencer443460a2006-11-09 21:15:49 +0000[diff] [blame]4466
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4467<!-- ======================================================================= -->
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]4468<div class="doc_subsection"> <a name="convertops">Conversion Operations</a>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4469</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4470
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4471<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4472
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]4473<p>The instructions in this category are the conversion instructions (casting)
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4474 which all take a single operand and a type. They perform various bit
4475 conversions on the operand.</p>
4476
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4477</div>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]4478
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]4479<!-- _______________________________________________________________________ -->
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]4480<div class="doc_subsubsection">
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4481 <a name="i_trunc">'<tt>trunc .. to</tt>' Instruction</a>
4482</div>
4483<div class="doc_text">
4484
4485<h5>Syntax:</h5>
4486<pre>
4487 &lt;result&gt; = trunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4488</pre>
4489
4490<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4491<p>The '<tt>trunc</tt>' instruction truncates its operand to the
4492 type <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4493
4494<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4495<p>The '<tt>trunc</tt>' instruction takes a <tt>value</tt> to trunc, which must
4496 be an <a href="#t_integer">integer</a> type, and a type that specifies the
4497 size and type of the result, which must be
4498 an <a href="#t_integer">integer</a> type. The bit size of <tt>value</tt> must
4499 be larger than the bit size of <tt>ty2</tt>. Equal sized types are not
4500 allowed.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4501
4502<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4503<p>The '<tt>trunc</tt>' instruction truncates the high order bits
4504 in <tt>value</tt> and converts the remaining bits to <tt>ty2</tt>. Since the
4505 source size must be larger than the destination size, <tt>trunc</tt> cannot
4506 be a <i>no-op cast</i>. It will always truncate bits.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4507
4508<h5>Example:</h5>
4509<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4510 %X = trunc i32 257 to i8 <i>; yields i8:1</i>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]4511 %Y = trunc i32 123 to i1 <i>; yields i1:true</i>
Gabor Greiff50fd572009-10-28 09:21:30 +0000[diff] [blame]4512 %Z = trunc i32 122 to i1 <i>; yields i1:false</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4513</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4514
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4515</div>
4516
4517<!-- _______________________________________________________________________ -->
4518<div class="doc_subsubsection">
4519 <a name="i_zext">'<tt>zext .. to</tt>' Instruction</a>
4520</div>
4521<div class="doc_text">
4522
4523<h5>Syntax:</h5>
4524<pre>
4525 &lt;result&gt; = zext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4526</pre>
4527
4528<h5>Overview:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4529<p>The '<tt>zext</tt>' instruction zero extends its operand to type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4530 <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4531
4532
4533<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4534<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]4535 <a href="#t_integer">integer</a> type, and a type to cast it to, which must
4536 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]4537 <tt>value</tt> must be smaller than the bit size of the destination type,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4538 <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4539
4540<h5>Semantics:</h5>
4541<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]4542 bits until it reaches the size of the destination type, <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4543
Reid Spencer07c9c682007-01-12 15:46:11 +0000[diff] [blame]4544<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]4545
4546<h5>Example:</h5>
4547<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4548 %X = zext i32 257 to i64 <i>; yields i64:257</i>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]4549 %Y = zext i1 true to i32 <i>; yields i32:1</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4550</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4551
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4552</div>
4553
4554<!-- _______________________________________________________________________ -->
4555<div class="doc_subsubsection">
4556 <a name="i_sext">'<tt>sext .. to</tt>' Instruction</a>
4557</div>
4558<div class="doc_text">
4559
4560<h5>Syntax:</h5>
4561<pre>
4562 &lt;result&gt; = sext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4563</pre>
4564
4565<h5>Overview:</h5>
4566<p>The '<tt>sext</tt>' sign extends <tt>value</tt> to the type <tt>ty2</tt>.</p>
4567
4568<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4569<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]4570 <a href="#t_integer">integer</a> type, and a type to cast it to, which must
4571 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]4572 <tt>value</tt> must be smaller than the bit size of the destination type,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4573 <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4574
4575<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4576<p>The '<tt>sext</tt>' instruction performs a sign extension by copying the sign
4577 bit (highest order bit) of the <tt>value</tt> until it reaches the bit size
4578 of the type <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4579
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]4580<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]4581
4582<h5>Example:</h5>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4583<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4584 %X = sext i8 -1 to i16 <i>; yields i16 :65535</i>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]4585 %Y = sext i1 true to i32 <i>; yields i32:-1</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4586</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4587
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4588</div>
4589
4590<!-- _______________________________________________________________________ -->
4591<div class="doc_subsubsection">
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]4592 <a name="i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a>
4593</div>
4594
4595<div class="doc_text">
4596
4597<h5>Syntax:</h5>
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]4598<pre>
4599 &lt;result&gt; = fptrunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4600</pre>
4601
4602<h5>Overview:</h5>
4603<p>The '<tt>fptrunc</tt>' instruction truncates <tt>value</tt> to type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4604 <tt>ty2</tt>.</p>
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]4605
4606<h5>Arguments:</h5>
4607<p>The '<tt>fptrunc</tt>' instruction takes a <a href="#t_floating">floating
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4608 point</a> value to cast and a <a href="#t_floating">floating point</a> type
4609 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]4610 <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]4611 <i>no-op cast</i>.</p>
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]4612
4613<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4614<p>The '<tt>fptrunc</tt>' instruction truncates a <tt>value</tt> from a larger
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4615 <a href="#t_floating">floating point</a> type to a smaller
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4616 <a href="#t_floating">floating point</a> type. If the value cannot fit
4617 within the destination type, <tt>ty2</tt>, then the results are
4618 undefined.</p>
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]4619
4620<h5>Example:</h5>
4621<pre>
4622 %X = fptrunc double 123.0 to float <i>; yields float:123.0</i>
4623 %Y = fptrunc double 1.0E+300 to float <i>; yields undefined</i>
4624</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4625
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]4626</div>
4627
4628<!-- _______________________________________________________________________ -->
4629<div class="doc_subsubsection">
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4630 <a name="i_fpext">'<tt>fpext .. to</tt>' Instruction</a>
4631</div>
4632<div class="doc_text">
4633
4634<h5>Syntax:</h5>
4635<pre>
4636 &lt;result&gt; = fpext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4637</pre>
4638
4639<h5>Overview:</h5>
4640<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]4641 floating point value.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4642
4643<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4644<p>The '<tt>fpext</tt>' instruction takes a
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4645 <a href="#t_floating">floating point</a> <tt>value</tt> to cast, and
4646 a <a href="#t_floating">floating point</a> type to cast it to. The source
4647 type must be smaller than the destination type.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4648
4649<h5>Semantics:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]4650<p>The '<tt>fpext</tt>' instruction extends the <tt>value</tt> from a smaller
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4651 <a href="#t_floating">floating point</a> type to a larger
4652 <a href="#t_floating">floating point</a> type. The <tt>fpext</tt> cannot be
4653 used to make a <i>no-op cast</i> because it always changes bits. Use
4654 <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]4655
4656<h5>Example:</h5>
4657<pre>
4658 %X = fpext float 3.1415 to double <i>; yields double:3.1415</i>
4659 %Y = fpext float 1.0 to float <i>; yields float:1.0 (no-op)</i>
4660</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4661
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4662</div>
4663
4664<!-- _______________________________________________________________________ -->
4665<div class="doc_subsubsection">
Reid Spencer2eadb532007-01-21 00:29:26 +0000[diff] [blame]4666 <a name="i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4667</div>
4668<div class="doc_text">
4669
4670<h5>Syntax:</h5>
4671<pre>
Reid Spencer753163d2007-07-31 14:40:14 +0000[diff] [blame]4672 &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]4673</pre>
4674
4675<h5>Overview:</h5>
Reid Spencer753163d2007-07-31 14:40:14 +0000[diff] [blame]4676<p>The '<tt>fptoui</tt>' converts a floating point <tt>value</tt> to its
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4677 unsigned integer equivalent of type <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4678
4679<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4680<p>The '<tt>fptoui</tt>' instruction takes a value to cast, which must be a
4681 scalar or vector <a href="#t_floating">floating point</a> value, and a type
4682 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
4683 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
4684 vector integer type with the same number of elements as <tt>ty</tt></p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4685
4686<h5>Semantics:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4687<p>The '<tt>fptoui</tt>' instruction converts its
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4688 <a href="#t_floating">floating point</a> operand into the nearest (rounding
4689 towards zero) unsigned integer value. If the value cannot fit
4690 in <tt>ty2</tt>, the results are undefined.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4691
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4692<h5>Example:</h5>
4693<pre>
Reid Spencer753163d2007-07-31 14:40:14 +0000[diff] [blame]4694 %X = fptoui double 123.0 to i32 <i>; yields i32:123</i>
Chris Lattner5b95a172007-09-22 03:17:52 +0000[diff] [blame]4695 %Y = fptoui float 1.0E+300 to i1 <i>; yields undefined:1</i>
Gabor Greiff50fd572009-10-28 09:21:30 +0000[diff] [blame]4696 %Z = fptoui float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4697</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4698
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4699</div>
4700
4701<!-- _______________________________________________________________________ -->
4702<div class="doc_subsubsection">
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]4703 <a name="i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4704</div>
4705<div class="doc_text">
4706
4707<h5>Syntax:</h5>
4708<pre>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]4709 &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]4710</pre>
4711
4712<h5>Overview:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4713<p>The '<tt>fptosi</tt>' instruction converts
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4714 <a href="#t_floating">floating point</a> <tt>value</tt> to
4715 type <tt>ty2</tt>.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]4716
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]4717<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4718<p>The '<tt>fptosi</tt>' instruction takes a value to cast, which must be a
4719 scalar or vector <a href="#t_floating">floating point</a> value, and a type
4720 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
4721 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
4722 vector integer type with the same number of elements as <tt>ty</tt></p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]4723
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]4724<h5>Semantics:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4725<p>The '<tt>fptosi</tt>' instruction converts its
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4726 <a href="#t_floating">floating point</a> operand into the nearest (rounding
4727 towards zero) signed integer value. If the value cannot fit in <tt>ty2</tt>,
4728 the results are undefined.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]4729
Chris Lattner70de6632001-07-09 00:26:23 +0000[diff] [blame]4730<h5>Example:</h5>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]4731<pre>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]4732 %X = fptosi double -123.0 to i32 <i>; yields i32:-123</i>
Chris Lattner5b95a172007-09-22 03:17:52 +0000[diff] [blame]4733 %Y = fptosi float 1.0E-247 to i1 <i>; yields undefined:1</i>
Gabor Greiff50fd572009-10-28 09:21:30 +0000[diff] [blame]4734 %Z = fptosi float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4735</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4736
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4737</div>
4738
4739<!-- _______________________________________________________________________ -->
4740<div class="doc_subsubsection">
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]4741 <a name="i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4742</div>
4743<div class="doc_text">
4744
4745<h5>Syntax:</h5>
4746<pre>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]4747 &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]4748</pre>
4749
4750<h5>Overview:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]4751<p>The '<tt>uitofp</tt>' instruction regards <tt>value</tt> as an unsigned
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4752 integer and converts that value to the <tt>ty2</tt> type.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4753
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4754<h5>Arguments:</h5>
Nate Begemand4d45c22007-11-17 03:58:34 +0000[diff] [blame]4755<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]4756 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
4757 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
4758 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
4759 floating point type with the same number of elements as <tt>ty</tt></p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4760
4761<h5>Semantics:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]4762<p>The '<tt>uitofp</tt>' instruction interprets its operand as an unsigned
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4763 integer quantity and converts it to the corresponding floating point
4764 value. If the value cannot fit in the floating point value, the results are
4765 undefined.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4766
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4767<h5>Example:</h5>
4768<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4769 %X = uitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]4770 %Y = uitofp i8 -1 to double <i>; yields double:255.0</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4771</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4772
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4773</div>
4774
4775<!-- _______________________________________________________________________ -->
4776<div class="doc_subsubsection">
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]4777 <a name="i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4778</div>
4779<div class="doc_text">
4780
4781<h5>Syntax:</h5>
4782<pre>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]4783 &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]4784</pre>
4785
4786<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4787<p>The '<tt>sitofp</tt>' instruction regards <tt>value</tt> as a signed integer
4788 and converts that value to the <tt>ty2</tt> type.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4789
4790<h5>Arguments:</h5>
Nate Begemand4d45c22007-11-17 03:58:34 +0000[diff] [blame]4791<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]4792 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
4793 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
4794 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
4795 floating point type with the same number of elements as <tt>ty</tt></p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4796
4797<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4798<p>The '<tt>sitofp</tt>' instruction interprets its operand as a signed integer
4799 quantity and converts it to the corresponding floating point value. If the
4800 value cannot fit in the floating point value, the results are undefined.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4801
4802<h5>Example:</h5>
4803<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4804 %X = sitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]4805 %Y = sitofp i8 -1 to double <i>; yields double:-1.0</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4806</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4807
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4808</div>
4809
4810<!-- _______________________________________________________________________ -->
4811<div class="doc_subsubsection">
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]4812 <a name="i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a>
4813</div>
4814<div class="doc_text">
4815
4816<h5>Syntax:</h5>
4817<pre>
4818 &lt;result&gt; = ptrtoint &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4819</pre>
4820
4821<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4822<p>The '<tt>ptrtoint</tt>' instruction converts the pointer <tt>value</tt> to
4823 the integer type <tt>ty2</tt>.</p>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]4824
4825<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4826<p>The '<tt>ptrtoint</tt>' instruction takes a <tt>value</tt> to cast, which
4827 must be a <a href="#t_pointer">pointer</a> value, and a type to cast it to
4828 <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]4829
4830<h5>Semantics:</h5>
4831<p>The '<tt>ptrtoint</tt>' instruction converts <tt>value</tt> to integer type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4832 <tt>ty2</tt> by interpreting the pointer value as an integer and either
4833 truncating or zero extending that value to the size of the integer type. If
4834 <tt>value</tt> is smaller than <tt>ty2</tt> then a zero extension is done. If
4835 <tt>value</tt> is larger than <tt>ty2</tt> then a truncation is done. If they
4836 are the same size, then nothing is done (<i>no-op cast</i>) other than a type
4837 change.</p>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]4838
4839<h5>Example:</h5>
4840<pre>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]4841 %X = ptrtoint i32* %X to i8 <i>; yields truncation on 32-bit architecture</i>
4842 %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]4843</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4844
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]4845</div>
4846
4847<!-- _______________________________________________________________________ -->
4848<div class="doc_subsubsection">
4849 <a name="i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a>
4850</div>
4851<div class="doc_text">
4852
4853<h5>Syntax:</h5>
4854<pre>
4855 &lt;result&gt; = inttoptr &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4856</pre>
4857
4858<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4859<p>The '<tt>inttoptr</tt>' instruction converts an integer <tt>value</tt> to a
4860 pointer type, <tt>ty2</tt>.</p>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]4861
4862<h5>Arguments:</h5>
Duncan Sands16f122e2007-03-30 12:22:09 +0000[diff] [blame]4863<p>The '<tt>inttoptr</tt>' instruction takes an <a href="#t_integer">integer</a>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4864 value to cast, and a type to cast it to, which must be a
4865 <a href="#t_pointer">pointer</a> type.</p>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]4866
4867<h5>Semantics:</h5>
4868<p>The '<tt>inttoptr</tt>' instruction converts <tt>value</tt> to type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4869 <tt>ty2</tt> by applying either a zero extension or a truncation depending on
4870 the size of the integer <tt>value</tt>. If <tt>value</tt> is larger than the
4871 size of a pointer then a truncation is done. If <tt>value</tt> is smaller
4872 than the size of a pointer then a zero extension is done. If they are the
4873 same size, nothing is done (<i>no-op cast</i>).</p>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]4874
4875<h5>Example:</h5>
4876<pre>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]4877 %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]4878 %Y = inttoptr i32 255 to i32* <i>; yields no-op on 32-bit architecture</i>
4879 %Z = inttoptr i64 0 to i32* <i>; yields truncation on 32-bit architecture</i>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]4880</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4881
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]4882</div>
4883
4884<!-- _______________________________________________________________________ -->
4885<div class="doc_subsubsection">
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]4886 <a name="i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4887</div>
4888<div class="doc_text">
4889
4890<h5>Syntax:</h5>
4891<pre>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]4892 &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]4893</pre>
4894
4895<h5>Overview:</h5>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]4896<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4897 <tt>ty2</tt> without changing any bits.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4898
4899<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4900<p>The '<tt>bitcast</tt>' instruction takes a value to cast, which must be a
4901 non-aggregate first class value, and a type to cast it to, which must also be
4902 a non-aggregate <a href="#t_firstclass">first class</a> type. The bit sizes
4903 of <tt>value</tt> and the destination type, <tt>ty2</tt>, must be
4904 identical. If the source type is a pointer, the destination type must also be
4905 a pointer. This instruction supports bitwise conversion of vectors to
4906 integers and to vectors of other types (as long as they have the same
4907 size).</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4908
4909<h5>Semantics:</h5>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]4910<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4911 <tt>ty2</tt>. It is always a <i>no-op cast</i> because no bits change with
4912 this conversion. The conversion is done as if the <tt>value</tt> had been
4913 stored to memory and read back as type <tt>ty2</tt>. Pointer types may only
4914 be converted to other pointer types with this instruction. To convert
4915 pointers to other types, use the <a href="#i_inttoptr">inttoptr</a> or
4916 <a href="#i_ptrtoint">ptrtoint</a> instructions first.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4917
4918<h5>Example:</h5>
4919<pre>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]4920 %X = bitcast i8 255 to i8 <i>; yields i8 :-1</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4921 %Y = bitcast i32* %x to sint* <i>; yields sint*:%x</i>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4922 %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]4923</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4924
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4925</div>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]4926
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]4927<!-- ======================================================================= -->
4928<div class="doc_subsection"> <a name="otherops">Other Operations</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4929
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]4930<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4931
4932<p>The instructions in this category are the "miscellaneous" instructions, which
4933 defy better classification.</p>
4934
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]4935</div>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4936
4937<!-- _______________________________________________________________________ -->
4938<div class="doc_subsubsection"><a name="i_icmp">'<tt>icmp</tt>' Instruction</a>
4939</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4940
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4941<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4942
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4943<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4944<pre>
4945 &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]4946</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4947
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4948<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4949<p>The '<tt>icmp</tt>' instruction returns a boolean value or a vector of
4950 boolean values based on comparison of its two integer, integer vector, or
4951 pointer operands.</p>
4952
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4953<h5>Arguments:</h5>
4954<p>The '<tt>icmp</tt>' instruction takes three operands. The first operand is
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4955 the condition code indicating the kind of comparison to perform. It is not a
4956 value, just a keyword. The possible condition code are:</p>
4957
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4958<ol>
4959 <li><tt>eq</tt>: equal</li>
4960 <li><tt>ne</tt>: not equal </li>
4961 <li><tt>ugt</tt>: unsigned greater than</li>
4962 <li><tt>uge</tt>: unsigned greater or equal</li>
4963 <li><tt>ult</tt>: unsigned less than</li>
4964 <li><tt>ule</tt>: unsigned less or equal</li>
4965 <li><tt>sgt</tt>: signed greater than</li>
4966 <li><tt>sge</tt>: signed greater or equal</li>
4967 <li><tt>slt</tt>: signed less than</li>
4968 <li><tt>sle</tt>: signed less or equal</li>
4969</ol>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4970
Chris Lattnerc0f423a2007-01-15 01:54:13 +0000[diff] [blame]4971<p>The remaining two arguments must be <a href="#t_integer">integer</a> or
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4972 <a href="#t_pointer">pointer</a> or integer <a href="#t_vector">vector</a>
4973 typed. They must also be identical types.</p>
4974
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4975<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4976<p>The '<tt>icmp</tt>' compares <tt>op1</tt> and <tt>op2</tt> according to the
4977 condition code given as <tt>cond</tt>. The comparison performed always yields
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]4978 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]4979 result, as follows:</p>
4980
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4981<ol>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4982 <li><tt>eq</tt>: yields <tt>true</tt> if the operands are equal,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4983 <tt>false</tt> otherwise. No sign interpretation is necessary or
4984 performed.</li>
4985
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4986 <li><tt>ne</tt>: yields <tt>true</tt> if the operands are unequal,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4987 <tt>false</tt> otherwise. No sign interpretation is necessary or
4988 performed.</li>
4989
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4990 <li><tt>ugt</tt>: interprets the operands as unsigned values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4991 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
4992
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4993 <li><tt>uge</tt>: interprets the operands as unsigned values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4994 <tt>true</tt> if <tt>op1</tt> is greater than or equal
4995 to <tt>op2</tt>.</li>
4996
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4997 <li><tt>ult</tt>: interprets the operands as unsigned values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4998 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
4999
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5000 <li><tt>ule</tt>: interprets the operands as unsigned values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5001 <tt>true</tt> if <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
5002
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5003 <li><tt>sgt</tt>: interprets the operands as signed values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5004 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
5005
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5006 <li><tt>sge</tt>: interprets the operands as signed values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5007 <tt>true</tt> if <tt>op1</tt> is greater than or equal
5008 to <tt>op2</tt>.</li>
5009
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5010 <li><tt>slt</tt>: interprets the operands as signed values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5011 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
5012
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5013 <li><tt>sle</tt>: interprets the operands as signed values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5014 <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]5015</ol>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5016
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5017<p>If the operands are <a href="#t_pointer">pointer</a> typed, the pointer
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5018 values are compared as if they were integers.</p>
5019
5020<p>If the operands are integer vectors, then they are compared element by
5021 element. The result is an <tt>i1</tt> vector with the same number of elements
5022 as the values being compared. Otherwise, the result is an <tt>i1</tt>.</p>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5023
5024<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5025<pre>
5026 &lt;result&gt; = icmp eq i32 4, 5 <i>; yields: result=false</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]5027 &lt;result&gt; = icmp ne float* %X, %X <i>; yields: result=false</i>
5028 &lt;result&gt; = icmp ult i16 4, 5 <i>; yields: result=true</i>
5029 &lt;result&gt; = icmp sgt i16 4, 5 <i>; yields: result=false</i>
5030 &lt;result&gt; = icmp ule i16 -4, 5 <i>; yields: result=false</i>
5031 &lt;result&gt; = icmp sge i16 4, 5 <i>; yields: result=false</i>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5032</pre>
Dan Gohmana5127ab2009-01-22 01:39:38 +0000[diff] [blame]5033
5034<p>Note that the code generator does not yet support vector types with
5035 the <tt>icmp</tt> instruction.</p>
5036
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5037</div>
5038
5039<!-- _______________________________________________________________________ -->
5040<div class="doc_subsubsection"><a name="i_fcmp">'<tt>fcmp</tt>' Instruction</a>
5041</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5042
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5043<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5044
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5045<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5046<pre>
5047 &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]5048</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5049
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5050<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5051<p>The '<tt>fcmp</tt>' instruction returns a boolean value or vector of boolean
5052 values based on comparison of its operands.</p>
5053
5054<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]5055(<a href="#t_integer"><tt>i1</tt></a>).</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5056
5057<p>If the operands are floating point vectors, then the result type is a vector
5058 of boolean with the same number of elements as the operands being
5059 compared.</p>
5060
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5061<h5>Arguments:</h5>
5062<p>The '<tt>fcmp</tt>' instruction takes three operands. The first operand is
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5063 the condition code indicating the kind of comparison to perform. It is not a
5064 value, just a keyword. The possible condition code are:</p>
5065
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5066<ol>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]5067 <li><tt>false</tt>: no comparison, always returns false</li>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5068 <li><tt>oeq</tt>: ordered and equal</li>
5069 <li><tt>ogt</tt>: ordered and greater than </li>
5070 <li><tt>oge</tt>: ordered and greater than or equal</li>
5071 <li><tt>olt</tt>: ordered and less than </li>
5072 <li><tt>ole</tt>: ordered and less than or equal</li>
5073 <li><tt>one</tt>: ordered and not equal</li>
5074 <li><tt>ord</tt>: ordered (no nans)</li>
5075 <li><tt>ueq</tt>: unordered or equal</li>
5076 <li><tt>ugt</tt>: unordered or greater than </li>
5077 <li><tt>uge</tt>: unordered or greater than or equal</li>
5078 <li><tt>ult</tt>: unordered or less than </li>
5079 <li><tt>ule</tt>: unordered or less than or equal</li>
5080 <li><tt>une</tt>: unordered or not equal</li>
5081 <li><tt>uno</tt>: unordered (either nans)</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]5082 <li><tt>true</tt>: no comparison, always returns true</li>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5083</ol>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5084
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5085<p><i>Ordered</i> means that neither operand is a QNAN while
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5086 <i>unordered</i> means that either operand may be a QNAN.</p>
5087
5088<p>Each of <tt>val1</tt> and <tt>val2</tt> arguments must be either
5089 a <a href="#t_floating">floating point</a> type or
5090 a <a href="#t_vector">vector</a> of floating point type. They must have
5091 identical types.</p>
5092
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5093<h5>Semantics:</h5>
Gabor Greif0f75ad02008-08-07 21:46:00 +0000[diff] [blame]5094<p>The '<tt>fcmp</tt>' instruction compares <tt>op1</tt> and <tt>op2</tt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5095 according to the condition code given as <tt>cond</tt>. If the operands are
5096 vectors, then the vectors are compared element by element. Each comparison
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]5097 performed always yields an <a href="#t_integer">i1</a> result, as
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5098 follows:</p>
5099
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5100<ol>
5101 <li><tt>false</tt>: always yields <tt>false</tt>, regardless of operands.</li>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5102
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5103 <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]5104 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
5105
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]5106 <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]5107 <tt>op1</tt> is greater than <tt>op2</tt>.</li>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5108
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5109 <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]5110 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
5111
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5112 <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]5113 <tt>op1</tt> is less than <tt>op2</tt>.</li>
5114
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5115 <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]5116 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
5117
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5118 <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]5119 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
5120
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]5121 <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]5122
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5123 <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]5124 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
5125
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5126 <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]5127 <tt>op1</tt> is greater than <tt>op2</tt>.</li>
5128
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5129 <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]5130 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
5131
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5132 <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]5133 <tt>op1</tt> is less than <tt>op2</tt>.</li>
5134
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5135 <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]5136 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
5137
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5138 <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]5139 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
5140
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]5141 <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]5142
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5143 <li><tt>true</tt>: always yields <tt>true</tt>, regardless of operands.</li>
5144</ol>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5145
5146<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5147<pre>
5148 &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]5149 &lt;result&gt; = fcmp one float 4.0, 5.0 <i>; yields: result=true</i>
5150 &lt;result&gt; = fcmp olt float 4.0, 5.0 <i>; yields: result=true</i>
5151 &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]5152</pre>
Dan Gohmana5127ab2009-01-22 01:39:38 +0000[diff] [blame]5153
5154<p>Note that the code generator does not yet support vector types with
5155 the <tt>fcmp</tt> instruction.</p>
5156
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5157</div>
5158
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5159<!-- _______________________________________________________________________ -->
Nate Begemand2195702008-05-12 19:01:56 +0000[diff] [blame]5160<div class="doc_subsubsection">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]5161 <a name="i_phi">'<tt>phi</tt>' Instruction</a>
5162</div>
5163
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5164<div class="doc_text">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]5165
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5166<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5167<pre>
5168 &lt;result&gt; = phi &lt;ty&gt; [ &lt;val0&gt;, &lt;label0&gt;], ...
5169</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]5170
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5171<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5172<p>The '<tt>phi</tt>' instruction is used to implement the &#966; node in the
5173 SSA graph representing the function.</p>
5174
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5175<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5176<p>The type of the incoming values is specified with the first type field. After
5177 this, the '<tt>phi</tt>' instruction takes a list of pairs as arguments, with
5178 one pair for each predecessor basic block of the current block. Only values
5179 of <a href="#t_firstclass">first class</a> type may be used as the value
5180 arguments to the PHI node. Only labels may be used as the label
5181 arguments.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]5182
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5183<p>There must be no non-phi instructions between the start of a basic block and
5184 the PHI instructions: i.e. PHI instructions must be first in a basic
5185 block.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]5186
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5187<p>For the purposes of the SSA form, the use of each incoming value is deemed to
5188 occur on the edge from the corresponding predecessor block to the current
5189 block (but after any definition of an '<tt>invoke</tt>' instruction's return
5190 value on the same edge).</p>
Jay Foad1a4eea52009-06-03 10:20:10 +0000[diff] [blame]5191
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5192<h5>Semantics:</h5>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5193<p>At runtime, the '<tt>phi</tt>' instruction logically takes on the value
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5194 specified by the pair corresponding to the predecessor basic block that
5195 executed just prior to the current block.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]5196
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5197<h5>Example:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]5198<pre>
5199Loop: ; Infinite loop that counts from 0 on up...
5200 %indvar = phi i32 [ 0, %LoopHeader ], [ %nextindvar, %Loop ]
5201 %nextindvar = add i32 %indvar, 1
5202 br label %Loop
5203</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5204
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5205</div>
5206
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5207<!-- _______________________________________________________________________ -->
5208<div class="doc_subsubsection">
5209 <a name="i_select">'<tt>select</tt>' Instruction</a>
5210</div>
5211
5212<div class="doc_text">
5213
5214<h5>Syntax:</h5>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5215<pre>
Dan Gohmanc579d972008-09-09 01:02:47 +0000[diff] [blame]5216 &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>
5217
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]5218 <i>selty</i> is either i1 or {&lt;N x i1&gt;}
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5219</pre>
5220
5221<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5222<p>The '<tt>select</tt>' instruction is used to choose one value based on a
5223 condition, without branching.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5224
5225
5226<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5227<p>The '<tt>select</tt>' instruction requires an 'i1' value or a vector of 'i1'
5228 values indicating the condition, and two values of the
5229 same <a href="#t_firstclass">first class</a> type. If the val1/val2 are
5230 vectors and the condition is a scalar, then entire vectors are selected, not
5231 individual elements.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5232
5233<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5234<p>If the condition is an i1 and it evaluates to 1, the instruction returns the
5235 first value argument; otherwise, it returns the second value argument.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5236
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5237<p>If the condition is a vector of i1, then the value arguments must be vectors
5238 of the same size, and the selection is done element by element.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5239
5240<h5>Example:</h5>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5241<pre>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]5242 %X = select i1 true, i8 17, i8 42 <i>; yields i8:17</i>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5243</pre>
Dan Gohmana5127ab2009-01-22 01:39:38 +0000[diff] [blame]5244
5245<p>Note that the code generator does not yet support conditions
5246 with vector type.</p>
5247
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5248</div>
5249
Robert Bocchinof72fdfe2006-01-15 20:48:27 +0000[diff] [blame]5250<!-- _______________________________________________________________________ -->
5251<div class="doc_subsubsection">
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5252 <a name="i_call">'<tt>call</tt>' Instruction</a>
5253</div>
5254
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5255<div class="doc_text">
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5256
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]5257<h5>Syntax:</h5>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5258<pre>
Devang Patel02256232008-10-07 17:48:33 +0000[diff] [blame]5259 &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]5260</pre>
5261
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]5262<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5263<p>The '<tt>call</tt>' instruction represents a simple function call.</p>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5264
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]5265<h5>Arguments:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5266<p>This instruction requires several arguments:</p>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5267
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]5268<ol>
Jeffrey Yasskinb8677462010-01-09 19:44:16 +0000[diff] [blame]5269 <li>The optional "tail" marker indicates that the callee function does not
5270 access any allocas or varargs in the caller. Note that calls may be
5271 marked "tail" even if they do not occur before
5272 a <a href="#i_ret"><tt>ret</tt></a> instruction. If the "tail" marker is
5273 present, the function call is eligible for tail call optimization,
5274 but <a href="CodeGenerator.html#tailcallopt">might not in fact be
Evan Cheng59676492010-03-08 21:05:02 +0000[diff] [blame]5275 optimized into a jump</a>. The code generator may optimize calls marked
5276 "tail" with either 1) automatic <a href="CodeGenerator.html#sibcallopt">
5277 sibling call optimization</a> when the caller and callee have
5278 matching signatures, or 2) forced tail call optimization when the
5279 following extra requirements are met:
Jeffrey Yasskinb8677462010-01-09 19:44:16 +0000[diff] [blame]5280 <ul>
5281 <li>Caller and callee both have the calling
5282 convention <tt>fastcc</tt>.</li>
5283 <li>The call is in tail position (ret immediately follows call and ret
5284 uses value of call or is void).</li>
5285 <li>Option <tt>-tailcallopt</tt> is enabled,
Dan Gohman6232f732010-03-02 01:08:11 +0000[diff] [blame]5286 or <code>llvm::GuaranteedTailCallOpt</code> is <code>true</code>.</li>
Jeffrey Yasskinb8677462010-01-09 19:44:16 +0000[diff] [blame]5287 <li><a href="CodeGenerator.html#tailcallopt">Platform specific
5288 constraints are met.</a></li>
5289 </ul>
5290 </li>
Devang Patel7e9b05e2008-10-06 18:50:38 +0000[diff] [blame]5291
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5292 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
5293 convention</a> the call should use. If none is specified, the call
Jeffrey Yasskinb8677462010-01-09 19:44:16 +0000[diff] [blame]5294 defaults to using C calling conventions. The calling convention of the
5295 call must match the calling convention of the target function, or else the
5296 behavior is undefined.</li>
Devang Patel7e9b05e2008-10-06 18:50:38 +0000[diff] [blame]5297
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5298 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
5299 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
5300 '<tt>inreg</tt>' attributes are valid here.</li>
5301
5302 <li>'<tt>ty</tt>': the type of the call instruction itself which is also the
5303 type of the return value. Functions that return no value are marked
5304 <tt><a href="#t_void">void</a></tt>.</li>
5305
5306 <li>'<tt>fnty</tt>': shall be the signature of the pointer to function value
5307 being invoked. The argument types must match the types implied by this
5308 signature. This type can be omitted if the function is not varargs and if
5309 the function type does not return a pointer to a function.</li>
5310
5311 <li>'<tt>fnptrval</tt>': An LLVM value containing a pointer to a function to
5312 be invoked. In most cases, this is a direct function invocation, but
5313 indirect <tt>call</tt>s are just as possible, calling an arbitrary pointer
5314 to function value.</li>
5315
5316 <li>'<tt>function args</tt>': argument list whose types match the function
Chris Lattner47f2a832010-03-02 06:36:51 +0000[diff] [blame]5317 signature argument types and parameter attributes. All arguments must be
5318 of <a href="#t_firstclass">first class</a> type. If the function
5319 signature indicates the function accepts a variable number of arguments,
5320 the extra arguments can be specified.</li>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5321
5322 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
5323 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
5324 '<tt>readnone</tt>' attributes are valid here.</li>
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]5325</ol>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5326
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]5327<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5328<p>The '<tt>call</tt>' instruction is used to cause control flow to transfer to
5329 a specified function, with its incoming arguments bound to the specified
5330 values. Upon a '<tt><a href="#i_ret">ret</a></tt>' instruction in the called
5331 function, control flow continues with the instruction after the function
5332 call, and the return value of the function is bound to the result
5333 argument.</p>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5334
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]5335<h5>Example:</h5>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5336<pre>
Nick Lewyckya9b13d52007-09-08 13:57:50 +0000[diff] [blame]5337 %retval = call i32 @test(i32 %argc)
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]5338 call i32 (i8*, ...)* @printf(i8* %msg, i32 12, i8 42) <i>; yields i32</i>
Chris Lattnerfb7c88d2008-03-21 17:24:17 +0000[diff] [blame]5339 %X = tail call i32 @foo() <i>; yields i32</i>
5340 %Y = tail call <a href="#callingconv">fastcc</a> i32 @foo() <i>; yields i32</i>
5341 call void %foo(i8 97 signext)
Devang Pateld6cff512008-03-10 20:49:15 +0000[diff] [blame]5342
5343 %struct.A = type { i32, i8 }
Devang Patel7e9b05e2008-10-06 18:50:38 +0000[diff] [blame]5344 %r = call %struct.A @foo() <i>; yields { 32, i8 }</i>
Dan Gohmancc3132e2008-10-04 19:00:07 +0000[diff] [blame]5345 %gr = extractvalue %struct.A %r, 0 <i>; yields i32</i>
5346 %gr1 = extractvalue %struct.A %r, 1 <i>; yields i8</i>
Chris Lattner6cbe8e92008-10-08 06:26:11 +0000[diff] [blame]5347 %Z = call void @foo() noreturn <i>; indicates that %foo never returns normally</i>
Matthijs Kooijmaneefa7df2008-10-07 10:03:45 +0000[diff] [blame]5348 %ZZ = call zeroext i32 @bar() <i>; Return value is %zero extended</i>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5349</pre>
5350
Dale Johannesen68f971b2009-09-24 18:38:21 +0000[diff] [blame]5351<p>llvm treats calls to some functions with names and arguments that match the
Dale Johannesen722212d2009-09-25 17:04:42 +0000[diff] [blame]5352standard C99 library as being the C99 library functions, and may perform
5353optimizations or generate code for them under that assumption. This is
5354something we'd like to change in the future to provide better support for
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]5355freestanding environments and non-C-based languages.</p>
Dale Johannesen68f971b2009-09-24 18:38:21 +0000[diff] [blame]5356
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5357</div>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5358
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5359<!-- _______________________________________________________________________ -->
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5360<div class="doc_subsubsection">
Chris Lattner33337472006-01-13 23:26:01 +0000[diff] [blame]5361 <a name="i_va_arg">'<tt>va_arg</tt>' Instruction</a>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5362</div>
5363
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5364<div class="doc_text">
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5365
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]5366<h5>Syntax:</h5>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5367<pre>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]5368 &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]5369</pre>
5370
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]5371<h5>Overview:</h5>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]5372<p>The '<tt>va_arg</tt>' instruction is used to access arguments passed through
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5373 the "variable argument" area of a function call. It is used to implement the
5374 <tt>va_arg</tt> macro in C.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5375
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]5376<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5377<p>This instruction takes a <tt>va_list*</tt> value and the type of the
5378 argument. It returns a value of the specified argument type and increments
5379 the <tt>va_list</tt> to point to the next argument. The actual type
5380 of <tt>va_list</tt> is target specific.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5381
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]5382<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5383<p>The '<tt>va_arg</tt>' instruction loads an argument of the specified type
5384 from the specified <tt>va_list</tt> and causes the <tt>va_list</tt> to point
5385 to the next argument. For more information, see the variable argument
5386 handling <a href="#int_varargs">Intrinsic Functions</a>.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5387
5388<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]5389 take a variable number of arguments, for example, the <tt>vfprintf</tt>
5390 function.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5391
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5392<p><tt>va_arg</tt> is an LLVM instruction instead of
5393 an <a href="#intrinsics">intrinsic function</a> because it takes a type as an
5394 argument.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5395
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]5396<h5>Example:</h5>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5397<p>See the <a href="#int_varargs">variable argument processing</a> section.</p>
5398
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5399<p>Note that the code generator does not yet fully support va_arg on many
5400 targets. Also, it does not currently support va_arg with aggregate types on
5401 any target.</p>
Dan Gohman3065b612009-01-12 23:12:39 +0000[diff] [blame]5402
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5403</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5404
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5405<!-- *********************************************************************** -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]5406<div class="doc_section"> <a name="intrinsics">Intrinsic Functions</a> </div>
5407<!-- *********************************************************************** -->
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5408
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5409<div class="doc_text">
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5410
5411<p>LLVM supports the notion of an "intrinsic function". These functions have
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5412 well known names and semantics and are required to follow certain
5413 restrictions. Overall, these intrinsics represent an extension mechanism for
5414 the LLVM language that does not require changing all of the transformations
5415 in LLVM when adding to the language (or the bitcode reader/writer, the
5416 parser, etc...).</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5417
John Criswell88190562005-05-16 16:17:45 +0000[diff] [blame]5418<p>Intrinsic function names must all start with an "<tt>llvm.</tt>" prefix. This
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5419 prefix is reserved in LLVM for intrinsic names; thus, function names may not
5420 begin with this prefix. Intrinsic functions must always be external
5421 functions: you cannot define the body of intrinsic functions. Intrinsic
5422 functions may only be used in call or invoke instructions: it is illegal to
5423 take the address of an intrinsic function. Additionally, because intrinsic
5424 functions are part of the LLVM language, it is required if any are added that
5425 they be documented here.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5426
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5427<p>Some intrinsic functions can be overloaded, i.e., the intrinsic represents a
5428 family of functions that perform the same operation but on different data
5429 types. Because LLVM can represent over 8 million different integer types,
5430 overloading is used commonly to allow an intrinsic function to operate on any
5431 integer type. One or more of the argument types or the result type can be
5432 overloaded to accept any integer type. Argument types may also be defined as
5433 exactly matching a previous argument's type or the result type. This allows
5434 an intrinsic function which accepts multiple arguments, but needs all of them
5435 to be of the same type, to only be overloaded with respect to a single
5436 argument or the result.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5437
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5438<p>Overloaded intrinsics will have the names of its overloaded argument types
5439 encoded into its function name, each preceded by a period. Only those types
5440 which are overloaded result in a name suffix. Arguments whose type is matched
5441 against another type do not. For example, the <tt>llvm.ctpop</tt> function
5442 can take an integer of any width and returns an integer of exactly the same
5443 integer width. This leads to a family of functions such as
5444 <tt>i8 @llvm.ctpop.i8(i8 %val)</tt> and <tt>i29 @llvm.ctpop.i29(i29
5445 %val)</tt>. Only one type, the return type, is overloaded, and only one type
5446 suffix is required. Because the argument's type is matched against the return
5447 type, it does not require its own name suffix.</p>
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]5448
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5449<p>To learn how to add an intrinsic function, please see the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5450 <a href="ExtendingLLVM.html">Extending LLVM Guide</a>.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5451
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5452</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5453
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5454<!-- ======================================================================= -->
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5455<div class="doc_subsection">
5456 <a name="int_varargs">Variable Argument Handling Intrinsics</a>
5457</div>
5458
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5459<div class="doc_text">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5460
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5461<p>Variable argument support is defined in LLVM with
5462 the <a href="#i_va_arg"><tt>va_arg</tt></a> instruction and these three
5463 intrinsic functions. These functions are related to the similarly named
5464 macros defined in the <tt>&lt;stdarg.h&gt;</tt> header file.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5465
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5466<p>All of these functions operate on arguments that use a target-specific value
5467 type "<tt>va_list</tt>". The LLVM assembly language reference manual does
5468 not define what this type is, so all transformations should be prepared to
5469 handle these functions regardless of the type used.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5470
Chris Lattner30b868d2006-05-15 17:26:46 +0000[diff] [blame]5471<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]5472 instruction and the variable argument handling intrinsic functions are
5473 used.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5474
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]5475<pre class="doc_code">
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]5476define i32 @test(i32 %X, ...) {
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5477 ; Initialize variable argument processing
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5478 %ap = alloca i8*
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]5479 %ap2 = bitcast i8** %ap to i8*
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]5480 call void @llvm.va_start(i8* %ap2)
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5481
5482 ; Read a single integer argument
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5483 %tmp = va_arg i8** %ap, i32
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5484
5485 ; Demonstrate usage of llvm.va_copy and llvm.va_end
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5486 %aq = alloca i8*
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]5487 %aq2 = bitcast i8** %aq to i8*
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5488 call void @llvm.va_copy(i8* %aq2, i8* %ap2)
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]5489 call void @llvm.va_end(i8* %aq2)
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5490
5491 ; Stop processing of arguments.
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]5492 call void @llvm.va_end(i8* %ap2)
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]5493 ret i32 %tmp
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5494}
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]5495
5496declare void @llvm.va_start(i8*)
5497declare void @llvm.va_copy(i8*, i8*)
5498declare void @llvm.va_end(i8*)
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5499</pre>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5500
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]5501</div>
5502
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5503<!-- _______________________________________________________________________ -->
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5504<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5505 <a name="int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5506</div>
5507
5508
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5509<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5510
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5511<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5512<pre>
5513 declare void %llvm.va_start(i8* &lt;arglist&gt;)
5514</pre>
5515
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5516<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5517<p>The '<tt>llvm.va_start</tt>' intrinsic initializes <tt>*&lt;arglist&gt;</tt>
5518 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]5519
5520<h5>Arguments:</h5>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]5521<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]5522
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5523<h5>Semantics:</h5>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]5524<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]5525 macro available in C. In a target-dependent way, it initializes
5526 the <tt>va_list</tt> element to which the argument points, so that the next
5527 call to <tt>va_arg</tt> will produce the first variable argument passed to
5528 the function. Unlike the C <tt>va_start</tt> macro, this intrinsic does not
5529 need to know the last argument of the function as the compiler can figure
5530 that out.</p>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]5531
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5532</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5533
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5534<!-- _______________________________________________________________________ -->
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5535<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5536 <a name="int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5537</div>
5538
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5539<div class="doc_text">
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]5540
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5541<h5>Syntax:</h5>
5542<pre>
5543 declare void @llvm.va_end(i8* &lt;arglist&gt;)
5544</pre>
5545
5546<h5>Overview:</h5>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5547<p>The '<tt>llvm.va_end</tt>' intrinsic destroys <tt>*&lt;arglist&gt;</tt>,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5548 which has been initialized previously
5549 with <tt><a href="#int_va_start">llvm.va_start</a></tt>
5550 or <tt><a href="#i_va_copy">llvm.va_copy</a></tt>.</p>
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]5551
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5552<h5>Arguments:</h5>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5553<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]5554
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5555<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5556<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]5557 macro available in C. In a target-dependent way, it destroys
5558 the <tt>va_list</tt> element to which the argument points. Calls
5559 to <a href="#int_va_start"><tt>llvm.va_start</tt></a>
5560 and <a href="#int_va_copy"> <tt>llvm.va_copy</tt></a> must be matched exactly
5561 with calls to <tt>llvm.va_end</tt>.</p>
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]5562
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5563</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5564
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5565<!-- _______________________________________________________________________ -->
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5566<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5567 <a name="int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5568</div>
5569
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5570<div class="doc_text">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5571
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5572<h5>Syntax:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5573<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]5574 declare void @llvm.va_copy(i8* &lt;destarglist&gt;, i8* &lt;srcarglist&gt;)
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5575</pre>
5576
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5577<h5>Overview:</h5>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5578<p>The '<tt>llvm.va_copy</tt>' intrinsic copies the current argument position
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5579 from the source argument list to the destination argument list.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5580
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5581<h5>Arguments:</h5>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]5582<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]5583 The second argument is a pointer to a <tt>va_list</tt> element to copy
5584 from.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5585
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5586<h5>Semantics:</h5>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5587<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]5588 macro available in C. In a target-dependent way, it copies the
5589 source <tt>va_list</tt> element into the destination <tt>va_list</tt>
5590 element. This intrinsic is necessary because
5591 the <tt><a href="#int_va_start"> llvm.va_start</a></tt> intrinsic may be
5592 arbitrarily complex and require, for example, memory allocation.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5593
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5594</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5595
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5596<!-- ======================================================================= -->
5597<div class="doc_subsection">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5598 <a name="int_gc">Accurate Garbage Collection Intrinsics</a>
5599</div>
5600
5601<div class="doc_text">
5602
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5603<p>LLVM support for <a href="GarbageCollection.html">Accurate Garbage
Chris Lattner67c37d12008-08-05 18:29:16 +0000[diff] [blame]5604Collection</a> (GC) requires the implementation and generation of these
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5605intrinsics. These intrinsics allow identification of <a href="#int_gcroot">GC
5606roots on the stack</a>, as well as garbage collector implementations that
5607require <a href="#int_gcread">read</a> and <a href="#int_gcwrite">write</a>
5608barriers. Front-ends for type-safe garbage collected languages should generate
5609these intrinsics to make use of the LLVM garbage collectors. For more details,
5610see <a href="GarbageCollection.html">Accurate Garbage Collection with
5611LLVM</a>.</p>
Christopher Lamb55c6d4f2007-12-17 01:00:21 +0000[diff] [blame]5612
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5613<p>The garbage collection intrinsics only operate on objects in the generic
5614 address space (address space zero).</p>
Christopher Lamb55c6d4f2007-12-17 01:00:21 +0000[diff] [blame]5615
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5616</div>
5617
5618<!-- _______________________________________________________________________ -->
5619<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5620 <a name="int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5621</div>
5622
5623<div class="doc_text">
5624
5625<h5>Syntax:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5626<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]5627 declare void @llvm.gcroot(i8** %ptrloc, i8* %metadata)
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5628</pre>
5629
5630<h5>Overview:</h5>
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]5631<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]5632 the code generator, and allows some metadata to be associated with it.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5633
5634<h5>Arguments:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5635<p>The first argument specifies the address of a stack object that contains the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5636 root pointer. The second pointer (which must be either a constant or a
5637 global value address) contains the meta-data to be associated with the
5638 root.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5639
5640<h5>Semantics:</h5>
Chris Lattner851b7712008-04-24 05:59:56 +0000[diff] [blame]5641<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]5642 location. At compile-time, the code generator generates information to allow
5643 the runtime to find the pointer at GC safe points. The '<tt>llvm.gcroot</tt>'
5644 intrinsic may only be used in a function which <a href="#gc">specifies a GC
5645 algorithm</a>.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5646
5647</div>
5648
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5649<!-- _______________________________________________________________________ -->
5650<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5651 <a name="int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5652</div>
5653
5654<div class="doc_text">
5655
5656<h5>Syntax:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5657<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]5658 declare i8* @llvm.gcread(i8* %ObjPtr, i8** %Ptr)
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5659</pre>
5660
5661<h5>Overview:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5662<p>The '<tt>llvm.gcread</tt>' intrinsic identifies reads of references from heap
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5663 locations, allowing garbage collector implementations that require read
5664 barriers.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5665
5666<h5>Arguments:</h5>
Chris Lattnerf9228072006-03-14 20:02:51 +0000[diff] [blame]5667<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]5668 allocated from the garbage collector. The first object is a pointer to the
5669 start of the referenced object, if needed by the language runtime (otherwise
5670 null).</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5671
5672<h5>Semantics:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5673<p>The '<tt>llvm.gcread</tt>' intrinsic has the same semantics as a load
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5674 instruction, but may be replaced with substantially more complex code by the
5675 garbage collector runtime, as needed. The '<tt>llvm.gcread</tt>' intrinsic
5676 may only be used in a function which <a href="#gc">specifies a GC
5677 algorithm</a>.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5678
5679</div>
5680
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5681<!-- _______________________________________________________________________ -->
5682<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5683 <a name="int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5684</div>
5685
5686<div class="doc_text">
5687
5688<h5>Syntax:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5689<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]5690 declare void @llvm.gcwrite(i8* %P1, i8* %Obj, i8** %P2)
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5691</pre>
5692
5693<h5>Overview:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5694<p>The '<tt>llvm.gcwrite</tt>' intrinsic identifies writes of references to heap
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5695 locations, allowing garbage collector implementations that require write
5696 barriers (such as generational or reference counting collectors).</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5697
5698<h5>Arguments:</h5>
Chris Lattnerf9228072006-03-14 20:02:51 +0000[diff] [blame]5699<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]5700 object to store it to, and the third is the address of the field of Obj to
5701 store to. If the runtime does not require a pointer to the object, Obj may
5702 be null.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5703
5704<h5>Semantics:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5705<p>The '<tt>llvm.gcwrite</tt>' intrinsic has the same semantics as a store
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5706 instruction, but may be replaced with substantially more complex code by the
5707 garbage collector runtime, as needed. The '<tt>llvm.gcwrite</tt>' intrinsic
5708 may only be used in a function which <a href="#gc">specifies a GC
5709 algorithm</a>.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5710
5711</div>
5712
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5713<!-- ======================================================================= -->
5714<div class="doc_subsection">
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5715 <a name="int_codegen">Code Generator Intrinsics</a>
5716</div>
5717
5718<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5719
5720<p>These intrinsics are provided by LLVM to expose special features that may
5721 only be implemented with code generator support.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5722
5723</div>
5724
5725<!-- _______________________________________________________________________ -->
5726<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5727 <a name="int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5728</div>
5729
5730<div class="doc_text">
5731
5732<h5>Syntax:</h5>
5733<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]5734 declare i8 *@llvm.returnaddress(i32 &lt;level&gt;)
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5735</pre>
5736
5737<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5738<p>The '<tt>llvm.returnaddress</tt>' intrinsic attempts to compute a
5739 target-specific value indicating the return address of the current function
5740 or one of its callers.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5741
5742<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5743<p>The argument to this intrinsic indicates which function to return the address
5744 for. Zero indicates the calling function, one indicates its caller, etc.
5745 The argument is <b>required</b> to be a constant integer value.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5746
5747<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5748<p>The '<tt>llvm.returnaddress</tt>' intrinsic either returns a pointer
5749 indicating the return address of the specified call frame, or zero if it
5750 cannot be identified. The value returned by this intrinsic is likely to be
5751 incorrect or 0 for arguments other than zero, so it should only be used for
5752 debugging purposes.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5753
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5754<p>Note that calling this intrinsic does not prevent function inlining or other
5755 aggressive transformations, so the value returned may not be that of the
5756 obvious source-language caller.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5757
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5758</div>
5759
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5760<!-- _______________________________________________________________________ -->
5761<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5762 <a name="int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5763</div>
5764
5765<div class="doc_text">
5766
5767<h5>Syntax:</h5>
5768<pre>
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]5769 declare i8* @llvm.frameaddress(i32 &lt;level&gt;)
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5770</pre>
5771
5772<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5773<p>The '<tt>llvm.frameaddress</tt>' intrinsic attempts to return the
5774 target-specific frame pointer value for the specified stack frame.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5775
5776<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5777<p>The argument to this intrinsic indicates which function to return the frame
5778 pointer for. Zero indicates the calling function, one indicates its caller,
5779 etc. The argument is <b>required</b> to be a constant integer value.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5780
5781<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5782<p>The '<tt>llvm.frameaddress</tt>' intrinsic either returns a pointer
5783 indicating the frame address of the specified call frame, or zero if it
5784 cannot be identified. The value returned by this intrinsic is likely to be
5785 incorrect or 0 for arguments other than zero, so it should only be used for
5786 debugging purposes.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5787
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5788<p>Note that calling this intrinsic does not prevent function inlining or other
5789 aggressive transformations, so the value returned may not be that of the
5790 obvious source-language caller.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5791
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5792</div>
5793
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]5794<!-- _______________________________________________________________________ -->
5795<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5796 <a name="int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]5797</div>
5798
5799<div class="doc_text">
5800
5801<h5>Syntax:</h5>
5802<pre>
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]5803 declare i8* @llvm.stacksave()
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]5804</pre>
5805
5806<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5807<p>The '<tt>llvm.stacksave</tt>' intrinsic is used to remember the current state
5808 of the function stack, for use
5809 with <a href="#int_stackrestore"> <tt>llvm.stackrestore</tt></a>. This is
5810 useful for implementing language features like scoped automatic variable
5811 sized arrays in C99.</p>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]5812
5813<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5814<p>This intrinsic returns a opaque pointer value that can be passed
5815 to <a href="#int_stackrestore"><tt>llvm.stackrestore</tt></a>. When
5816 an <tt>llvm.stackrestore</tt> intrinsic is executed with a value saved
5817 from <tt>llvm.stacksave</tt>, it effectively restores the state of the stack
5818 to the state it was in when the <tt>llvm.stacksave</tt> intrinsic executed.
5819 In practice, this pops any <a href="#i_alloca">alloca</a> blocks from the
5820 stack that were allocated after the <tt>llvm.stacksave</tt> was executed.</p>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]5821
5822</div>
5823
5824<!-- _______________________________________________________________________ -->
5825<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5826 <a name="int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]5827</div>
5828
5829<div class="doc_text">
5830
5831<h5>Syntax:</h5>
5832<pre>
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]5833 declare void @llvm.stackrestore(i8* %ptr)
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]5834</pre>
5835
5836<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5837<p>The '<tt>llvm.stackrestore</tt>' intrinsic is used to restore the state of
5838 the function stack to the state it was in when the
5839 corresponding <a href="#int_stacksave"><tt>llvm.stacksave</tt></a> intrinsic
5840 executed. This is useful for implementing language features like scoped
5841 automatic variable sized arrays in C99.</p>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]5842
5843<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5844<p>See the description
5845 for <a href="#int_stacksave"><tt>llvm.stacksave</tt></a>.</p>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]5846
5847</div>
5848
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]5849<!-- _______________________________________________________________________ -->
5850<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5851 <a name="int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a>
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]5852</div>
5853
5854<div class="doc_text">
5855
5856<h5>Syntax:</h5>
5857<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]5858 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]5859</pre>
5860
5861<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5862<p>The '<tt>llvm.prefetch</tt>' intrinsic is a hint to the code generator to
5863 insert a prefetch instruction if supported; otherwise, it is a noop.
5864 Prefetches have no effect on the behavior of the program but can change its
5865 performance characteristics.</p>
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]5866
5867<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5868<p><tt>address</tt> is the address to be prefetched, <tt>rw</tt> is the
5869 specifier determining if the fetch should be for a read (0) or write (1),
5870 and <tt>locality</tt> is a temporal locality specifier ranging from (0) - no
5871 locality, to (3) - extremely local keep in cache. The <tt>rw</tt>
5872 and <tt>locality</tt> arguments must be constant integers.</p>
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]5873
5874<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5875<p>This intrinsic does not modify the behavior of the program. In particular,
5876 prefetches cannot trap and do not produce a value. On targets that support
5877 this intrinsic, the prefetch can provide hints to the processor cache for
5878 better performance.</p>
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]5879
5880</div>
5881
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]5882<!-- _______________________________________________________________________ -->
5883<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5884 <a name="int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a>
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]5885</div>
5886
5887<div class="doc_text">
5888
5889<h5>Syntax:</h5>
5890<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]5891 declare void @llvm.pcmarker(i32 &lt;id&gt;)
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]5892</pre>
5893
5894<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5895<p>The '<tt>llvm.pcmarker</tt>' intrinsic is a method to export a Program
5896 Counter (PC) in a region of code to simulators and other tools. The method
5897 is target specific, but it is expected that the marker will use exported
5898 symbols to transmit the PC of the marker. The marker makes no guarantees
5899 that it will remain with any specific instruction after optimizations. It is
5900 possible that the presence of a marker will inhibit optimizations. The
5901 intended use is to be inserted after optimizations to allow correlations of
5902 simulation runs.</p>
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]5903
5904<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5905<p><tt>id</tt> is a numerical id identifying the marker.</p>
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]5906
5907<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5908<p>This intrinsic does not modify the behavior of the program. Backends that do
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]5909 not support this intrinsic may ignore it.</p>
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]5910
5911</div>
5912
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]5913<!-- _______________________________________________________________________ -->
5914<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5915 <a name="int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a>
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]5916</div>
5917
5918<div class="doc_text">
5919
5920<h5>Syntax:</h5>
5921<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]5922 declare i64 @llvm.readcyclecounter()
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]5923</pre>
5924
5925<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5926<p>The '<tt>llvm.readcyclecounter</tt>' intrinsic provides access to the cycle
5927 counter register (or similar low latency, high accuracy clocks) on those
5928 targets that support it. On X86, it should map to RDTSC. On Alpha, it
5929 should map to RPCC. As the backing counters overflow quickly (on the order
5930 of 9 seconds on alpha), this should only be used for small timings.</p>
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]5931
5932<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5933<p>When directly supported, reading the cycle counter should not modify any
5934 memory. Implementations are allowed to either return a application specific
5935 value or a system wide value. On backends without support, this is lowered
5936 to a constant 0.</p>
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]5937
5938</div>
5939
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5940<!-- ======================================================================= -->
5941<div class="doc_subsection">
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5942 <a name="int_libc">Standard C Library Intrinsics</a>
5943</div>
5944
5945<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5946
5947<p>LLVM provides intrinsics for a few important standard C library functions.
5948 These intrinsics allow source-language front-ends to pass information about
5949 the alignment of the pointer arguments to the code generator, providing
5950 opportunity for more efficient code generation.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5951
5952</div>
5953
5954<!-- _______________________________________________________________________ -->
5955<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5956 <a name="int_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5957</div>
5958
5959<div class="doc_text">
5960
5961<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5962<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]5963 integer bit width and for different address spaces. Not all targets support
5964 all bit widths however.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5965
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5966<pre>
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]5967 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]5968 i32 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]5969 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]5970 i64 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5971</pre>
5972
5973<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5974<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
5975 source location to the destination location.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5976
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5977<p>Note that, unlike the standard libc function, the <tt>llvm.memcpy.*</tt>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]5978 intrinsics do not return a value, takes extra alignment/isvolatile arguments
5979 and the pointers can be in specified address spaces.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5980
5981<h5>Arguments:</h5>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]5982
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5983<p>The first argument is a pointer to the destination, the second is a pointer
5984 to the source. The third argument is an integer argument specifying the
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]5985 number of bytes to copy, the fourth argument is the alignment of the
5986 source and destination locations, and the fifth is a boolean indicating a
5987 volatile access.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5988
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]5989<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]5990 then the caller guarantees that both the source and destination pointers are
5991 aligned to that boundary.</p>
Chris Lattner4c67c482004-02-12 21:18:15 +0000[diff] [blame]5992
Jeffrey Yasskin5d284ae2010-04-26 21:21:24 +0000[diff] [blame]5993<p>If the <tt>isvolatile</tt> parameter is <tt>true</tt>, the
5994 <tt>llvm.memcpy</tt> call is a <a href="#volatile">volatile operation</a>.
5995 The detailed access behavior is not very cleanly specified and it is unwise
5996 to depend on it.</p>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]5997
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5998<h5>Semantics:</h5>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]5999
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6000<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
6001 source location to the destination location, which are not allowed to
6002 overlap. It copies "len" bytes of memory over. If the argument is known to
6003 be aligned to some boundary, this can be specified as the fourth argument,
6004 otherwise it should be set to 0 or 1.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6005
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6006</div>
6007
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6008<!-- _______________________________________________________________________ -->
6009<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6010 <a name="int_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a>
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6011</div>
6012
6013<div class="doc_text">
6014
6015<h5>Syntax:</h5>
Chris Lattnerdd708342008-11-21 16:42:48 +0000[diff] [blame]6016<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]6017 width and for different address space. Not all targets support all bit
6018 widths however.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6019
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6020<pre>
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]6021 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]6022 i32 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]6023 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]6024 i64 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6025</pre>
6026
6027<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6028<p>The '<tt>llvm.memmove.*</tt>' intrinsics move a block of memory from the
6029 source location to the destination location. It is similar to the
6030 '<tt>llvm.memcpy</tt>' intrinsic but allows the two memory locations to
6031 overlap.</p>
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6032
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6033<p>Note that, unlike the standard libc function, the <tt>llvm.memmove.*</tt>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6034 intrinsics do not return a value, takes extra alignment/isvolatile arguments
6035 and the pointers can be in specified address spaces.</p>
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6036
6037<h5>Arguments:</h5>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6038
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6039<p>The first argument is a pointer to the destination, the second is a pointer
6040 to the source. The third argument is an integer argument specifying the
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6041 number of bytes to copy, the fourth argument is the alignment of the
6042 source and destination locations, and the fifth is a boolean indicating a
6043 volatile access.</p>
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6044
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]6045<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]6046 then the caller guarantees that the source and destination pointers are
6047 aligned to that boundary.</p>
Chris Lattner4c67c482004-02-12 21:18:15 +0000[diff] [blame]6048
Jeffrey Yasskin5d284ae2010-04-26 21:21:24 +0000[diff] [blame]6049<p>If the <tt>isvolatile</tt> parameter is <tt>true</tt>, the
6050 <tt>llvm.memmove</tt> call is a <a href="#volatile">volatile operation</a>.
6051 The detailed access behavior is not very cleanly specified and it is unwise
6052 to depend on it.</p>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6053
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6054<h5>Semantics:</h5>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6055
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6056<p>The '<tt>llvm.memmove.*</tt>' intrinsics copy a block of memory from the
6057 source location to the destination location, which may overlap. It copies
6058 "len" bytes of memory over. If the argument is known to be aligned to some
6059 boundary, this can be specified as the fourth argument, otherwise it should
6060 be set to 0 or 1.</p>
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6061
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6062</div>
6063
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6064<!-- _______________________________________________________________________ -->
6065<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6066 <a name="int_memset">'<tt>llvm.memset.*</tt>' Intrinsics</a>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6067</div>
6068
6069<div class="doc_text">
6070
6071<h5>Syntax:</h5>
Chris Lattnerdd708342008-11-21 16:42:48 +0000[diff] [blame]6072<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]6073 width and for different address spaces. However, not all targets support all
6074 bit widths.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6075
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6076<pre>
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]6077 declare void @llvm.memset.p0i8.i32(i8* &lt;dest&gt;, i8 &lt;val&gt;,
Chris Lattner685db9d2010-04-08 00:54:34 +0000[diff] [blame]6078 i32 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]6079 declare void @llvm.memset.p0i8.i64(i8* &lt;dest&gt;, i8 &lt;val&gt;,
Chris Lattner685db9d2010-04-08 00:54:34 +0000[diff] [blame]6080 i64 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6081</pre>
6082
6083<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6084<p>The '<tt>llvm.memset.*</tt>' intrinsics fill a block of memory with a
6085 particular byte value.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6086
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6087<p>Note that, unlike the standard libc function, the <tt>llvm.memset</tt>
John Criswellad05ae42010-07-30 16:30:28 +0000[diff] [blame]6088 intrinsic does not return a value and takes extra alignment/volatile
6089 arguments. Also, the destination can be in an arbitrary address space.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6090
6091<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6092<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]6093 byte value with which to fill it, the third argument is an integer argument
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6094 specifying the number of bytes to fill, and the fourth argument is the known
John Criswellad05ae42010-07-30 16:30:28 +0000[diff] [blame]6095 alignment of the destination location.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6096
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]6097<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]6098 then the caller guarantees that the destination pointer is aligned to that
6099 boundary.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6100
Jeffrey Yasskin5d284ae2010-04-26 21:21:24 +0000[diff] [blame]6101<p>If the <tt>isvolatile</tt> parameter is <tt>true</tt>, the
6102 <tt>llvm.memset</tt> call is a <a href="#volatile">volatile operation</a>.
6103 The detailed access behavior is not very cleanly specified and it is unwise
6104 to depend on it.</p>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6105
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6106<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6107<p>The '<tt>llvm.memset.*</tt>' intrinsics fill "len" bytes of memory starting
6108 at the destination location. If the argument is known to be aligned to some
6109 boundary, this can be specified as the fourth argument, otherwise it should
6110 be set to 0 or 1.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6111
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6112</div>
6113
Chris Lattner3b4f4372004-06-11 02:28:03 +0000[diff] [blame]6114<!-- _______________________________________________________________________ -->
6115<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6116 <a name="int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a>
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]6117</div>
6118
6119<div class="doc_text">
6120
6121<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6122<p>This is an overloaded intrinsic. You can use <tt>llvm.sqrt</tt> on any
6123 floating point or vector of floating point type. Not all targets support all
6124 types however.</p>
6125
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]6126<pre>
Dale Johannesendd89d272007-10-02 17:47:38 +0000[diff] [blame]6127 declare float @llvm.sqrt.f32(float %Val)
6128 declare double @llvm.sqrt.f64(double %Val)
6129 declare x86_fp80 @llvm.sqrt.f80(x86_fp80 %Val)
6130 declare fp128 @llvm.sqrt.f128(fp128 %Val)
6131 declare ppc_fp128 @llvm.sqrt.ppcf128(ppc_fp128 %Val)
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]6132</pre>
6133
6134<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6135<p>The '<tt>llvm.sqrt</tt>' intrinsics return the sqrt of the specified operand,
6136 returning the same value as the libm '<tt>sqrt</tt>' functions would.
6137 Unlike <tt>sqrt</tt> in libm, however, <tt>llvm.sqrt</tt> has undefined
6138 behavior for negative numbers other than -0.0 (which allows for better
6139 optimization, because there is no need to worry about errno being
6140 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]6141
6142<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6143<p>The argument and return value are floating point numbers of the same
6144 type.</p>
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]6145
6146<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6147<p>This function returns the sqrt of the specified operand if it is a
6148 nonnegative floating point number.</p>
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]6149
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]6150</div>
6151
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]6152<!-- _______________________________________________________________________ -->
6153<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6154 <a name="int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a>
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]6155</div>
6156
6157<div class="doc_text">
6158
6159<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6160<p>This is an overloaded intrinsic. You can use <tt>llvm.powi</tt> on any
6161 floating point or vector of floating point type. Not all targets support all
6162 types however.</p>
6163
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]6164<pre>
Dale Johannesendd89d272007-10-02 17:47:38 +0000[diff] [blame]6165 declare float @llvm.powi.f32(float %Val, i32 %power)
6166 declare double @llvm.powi.f64(double %Val, i32 %power)
6167 declare x86_fp80 @llvm.powi.f80(x86_fp80 %Val, i32 %power)
6168 declare fp128 @llvm.powi.f128(fp128 %Val, i32 %power)
6169 declare ppc_fp128 @llvm.powi.ppcf128(ppc_fp128 %Val, i32 %power)
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]6170</pre>
6171
6172<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6173<p>The '<tt>llvm.powi.*</tt>' intrinsics return the first operand raised to the
6174 specified (positive or negative) power. The order of evaluation of
6175 multiplications is not defined. When a vector of floating point type is
6176 used, the second argument remains a scalar integer value.</p>
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]6177
6178<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6179<p>The second argument is an integer power, and the first is a value to raise to
6180 that power.</p>
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]6181
6182<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6183<p>This function returns the first value raised to the second power with an
6184 unspecified sequence of rounding operations.</p>
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]6185
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]6186</div>
6187
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6188<!-- _______________________________________________________________________ -->
6189<div class="doc_subsubsection">
6190 <a name="int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a>
6191</div>
6192
6193<div class="doc_text">
6194
6195<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6196<p>This is an overloaded intrinsic. You can use <tt>llvm.sin</tt> on any
6197 floating point or vector of floating point type. Not all targets support all
6198 types however.</p>
6199
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6200<pre>
6201 declare float @llvm.sin.f32(float %Val)
6202 declare double @llvm.sin.f64(double %Val)
6203 declare x86_fp80 @llvm.sin.f80(x86_fp80 %Val)
6204 declare fp128 @llvm.sin.f128(fp128 %Val)
6205 declare ppc_fp128 @llvm.sin.ppcf128(ppc_fp128 %Val)
6206</pre>
6207
6208<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6209<p>The '<tt>llvm.sin.*</tt>' intrinsics return the sine of the operand.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6210
6211<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6212<p>The argument and return value are floating point numbers of the same
6213 type.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6214
6215<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6216<p>This function returns the sine of the specified operand, returning the same
6217 values as the libm <tt>sin</tt> functions would, and handles error conditions
6218 in the same way.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6219
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6220</div>
6221
6222<!-- _______________________________________________________________________ -->
6223<div class="doc_subsubsection">
6224 <a name="int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a>
6225</div>
6226
6227<div class="doc_text">
6228
6229<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6230<p>This is an overloaded intrinsic. You can use <tt>llvm.cos</tt> on any
6231 floating point or vector of floating point type. Not all targets support all
6232 types however.</p>
6233
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6234<pre>
6235 declare float @llvm.cos.f32(float %Val)
6236 declare double @llvm.cos.f64(double %Val)
6237 declare x86_fp80 @llvm.cos.f80(x86_fp80 %Val)
6238 declare fp128 @llvm.cos.f128(fp128 %Val)
6239 declare ppc_fp128 @llvm.cos.ppcf128(ppc_fp128 %Val)
6240</pre>
6241
6242<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6243<p>The '<tt>llvm.cos.*</tt>' intrinsics return the cosine of the operand.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6244
6245<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6246<p>The argument and return value are floating point numbers of the same
6247 type.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6248
6249<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6250<p>This function returns the cosine of the specified operand, returning the same
6251 values as the libm <tt>cos</tt> functions would, and handles error conditions
6252 in the same way.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6253
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6254</div>
6255
6256<!-- _______________________________________________________________________ -->
6257<div class="doc_subsubsection">
6258 <a name="int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a>
6259</div>
6260
6261<div class="doc_text">
6262
6263<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6264<p>This is an overloaded intrinsic. You can use <tt>llvm.pow</tt> on any
6265 floating point or vector of floating point type. Not all targets support all
6266 types however.</p>
6267
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6268<pre>
6269 declare float @llvm.pow.f32(float %Val, float %Power)
6270 declare double @llvm.pow.f64(double %Val, double %Power)
6271 declare x86_fp80 @llvm.pow.f80(x86_fp80 %Val, x86_fp80 %Power)
6272 declare fp128 @llvm.pow.f128(fp128 %Val, fp128 %Power)
6273 declare ppc_fp128 @llvm.pow.ppcf128(ppc_fp128 %Val, ppc_fp128 Power)
6274</pre>
6275
6276<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6277<p>The '<tt>llvm.pow.*</tt>' intrinsics return the first operand raised to the
6278 specified (positive or negative) power.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6279
6280<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6281<p>The second argument is a floating point power, and the first is a value to
6282 raise to that power.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6283
6284<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6285<p>This function returns the first value raised to the second power, returning
6286 the same values as the libm <tt>pow</tt> functions would, and handles error
6287 conditions in the same way.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6288
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6289</div>
6290
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6291<!-- ======================================================================= -->
6292<div class="doc_subsection">
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]6293 <a name="int_manip">Bit Manipulation Intrinsics</a>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6294</div>
6295
6296<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6297
6298<p>LLVM provides intrinsics for a few important bit manipulation operations.
6299 These allow efficient code generation for some algorithms.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6300
6301</div>
6302
6303<!-- _______________________________________________________________________ -->
6304<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6305 <a name="int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a>
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]6306</div>
6307
6308<div class="doc_text">
6309
6310<h5>Syntax:</h5>
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]6311<p>This is an overloaded intrinsic function. You can use bswap on any integer
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6312 type that is an even number of bytes (i.e. BitWidth % 16 == 0).</p>
6313
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]6314<pre>
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]6315 declare i16 @llvm.bswap.i16(i16 &lt;id&gt;)
6316 declare i32 @llvm.bswap.i32(i32 &lt;id&gt;)
6317 declare i64 @llvm.bswap.i64(i64 &lt;id&gt;)
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]6318</pre>
6319
6320<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6321<p>The '<tt>llvm.bswap</tt>' family of intrinsics is used to byte swap integer
6322 values with an even number of bytes (positive multiple of 16 bits). These
6323 are useful for performing operations on data that is not in the target's
6324 native byte order.</p>
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]6325
6326<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6327<p>The <tt>llvm.bswap.i16</tt> intrinsic returns an i16 value that has the high
6328 and low byte of the input i16 swapped. Similarly,
6329 the <tt>llvm.bswap.i32</tt> intrinsic returns an i32 value that has the four
6330 bytes of the input i32 swapped, so that if the input bytes are numbered 0, 1,
6331 2, 3 then the returned i32 will have its bytes in 3, 2, 1, 0 order.
6332 The <tt>llvm.bswap.i48</tt>, <tt>llvm.bswap.i64</tt> and other intrinsics
6333 extend this concept to additional even-byte lengths (6 bytes, 8 bytes and
6334 more, respectively).</p>
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]6335
6336</div>
6337
6338<!-- _______________________________________________________________________ -->
6339<div class="doc_subsubsection">
Reid Spencerb4f9a6f2006-01-16 21:12:35 +0000[diff] [blame]6340 <a name="int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic</a>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6341</div>
6342
6343<div class="doc_text">
6344
6345<h5>Syntax:</h5>
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]6346<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]6347 width. Not all targets support all bit widths however.</p>
6348
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6349<pre>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6350 declare i8 @llvm.ctpop.i8(i8 &lt;src&gt;)
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]6351 declare i16 @llvm.ctpop.i16(i16 &lt;src&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]6352 declare i32 @llvm.ctpop.i32(i32 &lt;src&gt;)
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]6353 declare i64 @llvm.ctpop.i64(i64 &lt;src&gt;)
6354 declare i256 @llvm.ctpop.i256(i256 &lt;src&gt;)
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6355</pre>
6356
6357<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6358<p>The '<tt>llvm.ctpop</tt>' family of intrinsics counts the number of bits set
6359 in a value.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6360
6361<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6362<p>The only argument is the value to be counted. The argument may be of any
6363 integer type. The return type must match the argument type.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6364
6365<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6366<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]6367
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6368</div>
6369
6370<!-- _______________________________________________________________________ -->
6371<div class="doc_subsubsection">
Chris Lattnerb748c672006-01-16 22:34:14 +0000[diff] [blame]6372 <a name="int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic</a>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6373</div>
6374
6375<div class="doc_text">
6376
6377<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6378<p>This is an overloaded intrinsic. You can use <tt>llvm.ctlz</tt> on any
6379 integer bit width. Not all targets support all bit widths however.</p>
6380
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6381<pre>
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]6382 declare i8 @llvm.ctlz.i8 (i8 &lt;src&gt;)
6383 declare i16 @llvm.ctlz.i16(i16 &lt;src&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]6384 declare i32 @llvm.ctlz.i32(i32 &lt;src&gt;)
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]6385 declare i64 @llvm.ctlz.i64(i64 &lt;src&gt;)
6386 declare i256 @llvm.ctlz.i256(i256 &lt;src&gt;)
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6387</pre>
6388
6389<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6390<p>The '<tt>llvm.ctlz</tt>' family of intrinsic functions counts the number of
6391 leading zeros in a variable.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6392
6393<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6394<p>The only argument is the value to be counted. The argument may be of any
6395 integer type. The return type must match the argument type.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6396
6397<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6398<p>The '<tt>llvm.ctlz</tt>' intrinsic counts the leading (most significant)
6399 zeros in a variable. If the src == 0 then the result is the size in bits of
6400 the type of src. For example, <tt>llvm.ctlz(i32 2) = 30</tt>.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6401
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6402</div>
Chris Lattner3b4f4372004-06-11 02:28:03 +0000[diff] [blame]6403
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]6404<!-- _______________________________________________________________________ -->
6405<div class="doc_subsubsection">
Chris Lattnerb748c672006-01-16 22:34:14 +0000[diff] [blame]6406 <a name="int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic</a>
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]6407</div>
6408
6409<div class="doc_text">
6410
6411<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6412<p>This is an overloaded intrinsic. You can use <tt>llvm.cttz</tt> on any
6413 integer bit width. Not all targets support all bit widths however.</p>
6414
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]6415<pre>
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]6416 declare i8 @llvm.cttz.i8 (i8 &lt;src&gt;)
6417 declare i16 @llvm.cttz.i16(i16 &lt;src&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]6418 declare i32 @llvm.cttz.i32(i32 &lt;src&gt;)
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]6419 declare i64 @llvm.cttz.i64(i64 &lt;src&gt;)
6420 declare i256 @llvm.cttz.i256(i256 &lt;src&gt;)
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]6421</pre>
6422
6423<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6424<p>The '<tt>llvm.cttz</tt>' family of intrinsic functions counts the number of
6425 trailing zeros.</p>
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]6426
6427<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6428<p>The only argument is the value to be counted. The argument may be of any
6429 integer type. The return type must match the argument type.</p>
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]6430
6431<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6432<p>The '<tt>llvm.cttz</tt>' intrinsic counts the trailing (least significant)
6433 zeros in a variable. If the src == 0 then the result is the size in bits of
6434 the type of src. For example, <tt>llvm.cttz(2) = 1</tt>.</p>
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]6435
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]6436</div>
6437
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]6438<!-- ======================================================================= -->
6439<div class="doc_subsection">
6440 <a name="int_overflow">Arithmetic with Overflow Intrinsics</a>
6441</div>
6442
6443<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6444
6445<p>LLVM provides intrinsics for some arithmetic with overflow operations.</p>
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]6446
6447</div>
6448
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6449<!-- _______________________________________________________________________ -->
6450<div class="doc_subsubsection">
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]6451 <a name="int_sadd_overflow">'<tt>llvm.sadd.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6452</div>
6453
6454<div class="doc_text">
6455
6456<h5>Syntax:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6457<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]6458 on any integer bit width.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6459
6460<pre>
6461 declare {i16, i1} @llvm.sadd.with.overflow.i16(i16 %a, i16 %b)
6462 declare {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
6463 declare {i64, i1} @llvm.sadd.with.overflow.i64(i64 %a, i64 %b)
6464</pre>
6465
6466<h5>Overview:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6467<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6468 a signed addition of the two arguments, and indicate whether an overflow
6469 occurred during the signed summation.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6470
6471<h5>Arguments:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6472<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]6473 be of integer types of any bit width, but they must have the same bit
6474 width. The second element of the result structure must be of
6475 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6476 undergo signed addition.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6477
6478<h5>Semantics:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6479<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6480 a signed addition of the two variables. They return a structure &mdash; the
6481 first element of which is the signed summation, and the second element of
6482 which is a bit specifying if the signed summation resulted in an
6483 overflow.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6484
6485<h5>Examples:</h5>
6486<pre>
6487 %res = call {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
6488 %sum = extractvalue {i32, i1} %res, 0
6489 %obit = extractvalue {i32, i1} %res, 1
6490 br i1 %obit, label %overflow, label %normal
6491</pre>
6492
6493</div>
6494
6495<!-- _______________________________________________________________________ -->
6496<div class="doc_subsubsection">
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]6497 <a name="int_uadd_overflow">'<tt>llvm.uadd.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6498</div>
6499
6500<div class="doc_text">
6501
6502<h5>Syntax:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6503<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]6504 on any integer bit width.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6505
6506<pre>
6507 declare {i16, i1} @llvm.uadd.with.overflow.i16(i16 %a, i16 %b)
6508 declare {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
6509 declare {i64, i1} @llvm.uadd.with.overflow.i64(i64 %a, i64 %b)
6510</pre>
6511
6512<h5>Overview:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6513<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6514 an unsigned addition of the two arguments, and indicate whether a carry
6515 occurred during the unsigned summation.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6516
6517<h5>Arguments:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6518<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]6519 be of integer types of any bit width, but they must have the same bit
6520 width. The second element of the result structure must be of
6521 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6522 undergo unsigned addition.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6523
6524<h5>Semantics:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6525<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6526 an unsigned addition of the two arguments. They return a structure &mdash;
6527 the first element of which is the sum, and the second element of which is a
6528 bit specifying if the unsigned summation resulted in a carry.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6529
6530<h5>Examples:</h5>
6531<pre>
6532 %res = call {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
6533 %sum = extractvalue {i32, i1} %res, 0
6534 %obit = extractvalue {i32, i1} %res, 1
6535 br i1 %obit, label %carry, label %normal
6536</pre>
6537
6538</div>
6539
6540<!-- _______________________________________________________________________ -->
6541<div class="doc_subsubsection">
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]6542 <a name="int_ssub_overflow">'<tt>llvm.ssub.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6543</div>
6544
6545<div class="doc_text">
6546
6547<h5>Syntax:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6548<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]6549 on any integer bit width.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6550
6551<pre>
6552 declare {i16, i1} @llvm.ssub.with.overflow.i16(i16 %a, i16 %b)
6553 declare {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
6554 declare {i64, i1} @llvm.ssub.with.overflow.i64(i64 %a, i64 %b)
6555</pre>
6556
6557<h5>Overview:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6558<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6559 a signed subtraction of the two arguments, and indicate whether an overflow
6560 occurred during the signed subtraction.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6561
6562<h5>Arguments:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6563<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]6564 be of integer types of any bit width, but they must have the same bit
6565 width. The second element of the result structure must be of
6566 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6567 undergo signed subtraction.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6568
6569<h5>Semantics:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6570<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6571 a signed subtraction of the two arguments. They return a structure &mdash;
6572 the first element of which is the subtraction, and the second element of
6573 which is a bit specifying if the signed subtraction resulted in an
6574 overflow.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6575
6576<h5>Examples:</h5>
6577<pre>
6578 %res = call {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
6579 %sum = extractvalue {i32, i1} %res, 0
6580 %obit = extractvalue {i32, i1} %res, 1
6581 br i1 %obit, label %overflow, label %normal
6582</pre>
6583
6584</div>
6585
6586<!-- _______________________________________________________________________ -->
6587<div class="doc_subsubsection">
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]6588 <a name="int_usub_overflow">'<tt>llvm.usub.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6589</div>
6590
6591<div class="doc_text">
6592
6593<h5>Syntax:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6594<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]6595 on any integer bit width.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6596
6597<pre>
6598 declare {i16, i1} @llvm.usub.with.overflow.i16(i16 %a, i16 %b)
6599 declare {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
6600 declare {i64, i1} @llvm.usub.with.overflow.i64(i64 %a, i64 %b)
6601</pre>
6602
6603<h5>Overview:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6604<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6605 an unsigned subtraction of the two arguments, and indicate whether an
6606 overflow occurred during the unsigned subtraction.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6607
6608<h5>Arguments:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6609<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]6610 be of integer types of any bit width, but they must have the same bit
6611 width. The second element of the result structure must be of
6612 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6613 undergo unsigned subtraction.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6614
6615<h5>Semantics:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6616<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6617 an unsigned subtraction of the two arguments. They return a structure &mdash;
6618 the first element of which is the subtraction, and the second element of
6619 which is a bit specifying if the unsigned subtraction resulted in an
6620 overflow.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6621
6622<h5>Examples:</h5>
6623<pre>
6624 %res = call {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
6625 %sum = extractvalue {i32, i1} %res, 0
6626 %obit = extractvalue {i32, i1} %res, 1
6627 br i1 %obit, label %overflow, label %normal
6628</pre>
6629
6630</div>
6631
6632<!-- _______________________________________________________________________ -->
6633<div class="doc_subsubsection">
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]6634 <a name="int_smul_overflow">'<tt>llvm.smul.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6635</div>
6636
6637<div class="doc_text">
6638
6639<h5>Syntax:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6640<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]6641 on any integer bit width.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6642
6643<pre>
6644 declare {i16, i1} @llvm.smul.with.overflow.i16(i16 %a, i16 %b)
6645 declare {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
6646 declare {i64, i1} @llvm.smul.with.overflow.i64(i64 %a, i64 %b)
6647</pre>
6648
6649<h5>Overview:</h5>
6650
6651<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6652 a signed multiplication of the two arguments, and indicate whether an
6653 overflow occurred during the signed multiplication.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6654
6655<h5>Arguments:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6656<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]6657 be of integer types of any bit width, but they must have the same bit
6658 width. The second element of the result structure must be of
6659 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6660 undergo signed multiplication.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6661
6662<h5>Semantics:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6663<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6664 a signed multiplication of the two arguments. They return a structure &mdash;
6665 the first element of which is the multiplication, and the second element of
6666 which is a bit specifying if the signed multiplication resulted in an
6667 overflow.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6668
6669<h5>Examples:</h5>
6670<pre>
6671 %res = call {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
6672 %sum = extractvalue {i32, i1} %res, 0
6673 %obit = extractvalue {i32, i1} %res, 1
6674 br i1 %obit, label %overflow, label %normal
6675</pre>
6676
Reid Spencer5bf54c82007-04-11 23:23:49 +0000[diff] [blame]6677</div>
6678
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]6679<!-- _______________________________________________________________________ -->
6680<div class="doc_subsubsection">
6681 <a name="int_umul_overflow">'<tt>llvm.umul.with.overflow.*</tt>' Intrinsics</a>
6682</div>
6683
6684<div class="doc_text">
6685
6686<h5>Syntax:</h5>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]6687<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]6688 on any integer bit width.</p>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]6689
6690<pre>
6691 declare {i16, i1} @llvm.umul.with.overflow.i16(i16 %a, i16 %b)
6692 declare {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
6693 declare {i64, i1} @llvm.umul.with.overflow.i64(i64 %a, i64 %b)
6694</pre>
6695
6696<h5>Overview:</h5>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]6697<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6698 a unsigned multiplication of the two arguments, and indicate whether an
6699 overflow occurred during the unsigned multiplication.</p>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]6700
6701<h5>Arguments:</h5>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]6702<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]6703 be of integer types of any bit width, but they must have the same bit
6704 width. The second element of the result structure must be of
6705 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6706 undergo unsigned multiplication.</p>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]6707
6708<h5>Semantics:</h5>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]6709<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6710 an unsigned multiplication of the two arguments. They return a structure
6711 &mdash; the first element of which is the multiplication, and the second
6712 element of which is a bit specifying if the unsigned multiplication resulted
6713 in an overflow.</p>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]6714
6715<h5>Examples:</h5>
6716<pre>
6717 %res = call {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
6718 %sum = extractvalue {i32, i1} %res, 0
6719 %obit = extractvalue {i32, i1} %res, 1
6720 br i1 %obit, label %overflow, label %normal
6721</pre>
6722
6723</div>
6724
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]6725<!-- ======================================================================= -->
6726<div class="doc_subsection">
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]6727 <a name="int_fp16">Half Precision Floating Point Intrinsics</a>
6728</div>
6729
6730<div class="doc_text">
6731
Chris Lattner022a9fb2010-03-15 04:12:21 +0000[diff] [blame]6732<p>Half precision floating point is a storage-only format. This means that it is
6733 a dense encoding (in memory) but does not support computation in the
6734 format.</p>
Chris Lattnerbbd8bd32010-03-14 23:03:31 +0000[diff] [blame]6735
Chris Lattner022a9fb2010-03-15 04:12:21 +0000[diff] [blame]6736<p>This means that code must first load the half-precision floating point
Chris Lattnerbbd8bd32010-03-14 23:03:31 +0000[diff] [blame]6737 value as an i16, then convert it to float with <a
6738 href="#int_convert_from_fp16"><tt>llvm.convert.from.fp16</tt></a>.
6739 Computation can then be performed on the float value (including extending to
Chris Lattner022a9fb2010-03-15 04:12:21 +0000[diff] [blame]6740 double etc). To store the value back to memory, it is first converted to
6741 float if needed, then converted to i16 with
Chris Lattnerbbd8bd32010-03-14 23:03:31 +0000[diff] [blame]6742 <a href="#int_convert_to_fp16"><tt>llvm.convert.to.fp16</tt></a>, then
6743 storing as an i16 value.</p>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]6744</div>
6745
6746<!-- _______________________________________________________________________ -->
6747<div class="doc_subsubsection">
Chris Lattnerbbd8bd32010-03-14 23:03:31 +0000[diff] [blame]6748 <a name="int_convert_to_fp16">'<tt>llvm.convert.to.fp16</tt>' Intrinsic</a>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]6749</div>
6750
6751<div class="doc_text">
6752
6753<h5>Syntax:</h5>
6754<pre>
6755 declare i16 @llvm.convert.to.fp16(f32 %a)
6756</pre>
6757
6758<h5>Overview:</h5>
6759<p>The '<tt>llvm.convert.to.fp16</tt>' intrinsic function performs
6760 a conversion from single precision floating point format to half precision
6761 floating point format.</p>
6762
6763<h5>Arguments:</h5>
6764<p>The intrinsic function contains single argument - the value to be
6765 converted.</p>
6766
6767<h5>Semantics:</h5>
6768<p>The '<tt>llvm.convert.to.fp16</tt>' intrinsic function performs
6769 a conversion from single precision floating point format to half precision
Chris Lattner022a9fb2010-03-15 04:12:21 +0000[diff] [blame]6770 floating point format. The return value is an <tt>i16</tt> which
Chris Lattnerbbd8bd32010-03-14 23:03:31 +0000[diff] [blame]6771 contains the converted number.</p>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]6772
6773<h5>Examples:</h5>
6774<pre>
6775 %res = call i16 @llvm.convert.to.fp16(f32 %a)
6776 store i16 %res, i16* @x, align 2
6777</pre>
6778
6779</div>
6780
6781<!-- _______________________________________________________________________ -->
6782<div class="doc_subsubsection">
Chris Lattnerbbd8bd32010-03-14 23:03:31 +0000[diff] [blame]6783 <a name="int_convert_from_fp16">'<tt>llvm.convert.from.fp16</tt>' Intrinsic</a>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]6784</div>
6785
6786<div class="doc_text">
6787
6788<h5>Syntax:</h5>
6789<pre>
6790 declare f32 @llvm.convert.from.fp16(i16 %a)
6791</pre>
6792
6793<h5>Overview:</h5>
6794<p>The '<tt>llvm.convert.from.fp16</tt>' intrinsic function performs
6795 a conversion from half precision floating point format to single precision
6796 floating point format.</p>
6797
6798<h5>Arguments:</h5>
6799<p>The intrinsic function contains single argument - the value to be
6800 converted.</p>
6801
6802<h5>Semantics:</h5>
6803<p>The '<tt>llvm.convert.from.fp16</tt>' intrinsic function performs a
Chris Lattner022a9fb2010-03-15 04:12:21 +0000[diff] [blame]6804 conversion from half single precision floating point format to single
Chris Lattnerbbd8bd32010-03-14 23:03:31 +0000[diff] [blame]6805 precision floating point format. The input half-float value is represented by
6806 an <tt>i16</tt> value.</p>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]6807
6808<h5>Examples:</h5>
6809<pre>
6810 %a = load i16* @x, align 2
6811 %res = call f32 @llvm.convert.from.fp16(i16 %a)
6812</pre>
6813
6814</div>
6815
6816<!-- ======================================================================= -->
6817<div class="doc_subsection">
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]6818 <a name="int_debugger">Debugger Intrinsics</a>
6819</div>
6820
6821<div class="doc_text">
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]6822
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6823<p>The LLVM debugger intrinsics (which all start with <tt>llvm.dbg.</tt>
6824 prefix), are described in
6825 the <a href="SourceLevelDebugging.html#format_common_intrinsics">LLVM Source
6826 Level Debugging</a> document.</p>
6827
6828</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]6829
Jim Laskey2211f492007-03-14 19:31:19 +0000[diff] [blame]6830<!-- ======================================================================= -->
6831<div class="doc_subsection">
6832 <a name="int_eh">Exception Handling Intrinsics</a>
6833</div>
6834
6835<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6836
6837<p>The LLVM exception handling intrinsics (which all start with
6838 <tt>llvm.eh.</tt> prefix), are described in
6839 the <a href="ExceptionHandling.html#format_common_intrinsics">LLVM Exception
6840 Handling</a> document.</p>
6841
Jim Laskey2211f492007-03-14 19:31:19 +0000[diff] [blame]6842</div>
6843
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]6844<!-- ======================================================================= -->
6845<div class="doc_subsection">
Duncan Sands86e01192007-09-11 14:10:23 +0000[diff] [blame]6846 <a name="int_trampoline">Trampoline Intrinsic</a>
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]6847</div>
6848
6849<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6850
6851<p>This intrinsic makes it possible to excise one parameter, marked with
Dan Gohman3770af52010-07-02 23:18:08 +0000[diff] [blame]6852 the <a href="#nest"><tt>nest</tt></a> attribute, from a function.
6853 The result is a callable
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6854 function pointer lacking the nest parameter - the caller does not need to
6855 provide a value for it. Instead, the value to use is stored in advance in a
6856 "trampoline", a block of memory usually allocated on the stack, which also
6857 contains code to splice the nest value into the argument list. This is used
6858 to implement the GCC nested function address extension.</p>
6859
6860<p>For example, if the function is
6861 <tt>i32 f(i8* nest %c, i32 %x, i32 %y)</tt> then the resulting function
6862 pointer has signature <tt>i32 (i32, i32)*</tt>. It can be created as
6863 follows:</p>
6864
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]6865<pre class="doc_code">
Duncan Sands86e01192007-09-11 14:10:23 +0000[diff] [blame]6866 %tramp = alloca [10 x i8], align 4 ; size and alignment only correct for X86
6867 %tramp1 = getelementptr [10 x i8]* %tramp, i32 0, i32 0
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]6868 %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]6869 %fp = bitcast i8* %p to i32 (i32, i32)*
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]6870</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6871
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]6872<p>The call <tt>%val = call i32 %fp(i32 %x, i32 %y)</tt> is then equivalent
6873 to <tt>%val = call i32 %f(i8* %nval, i32 %x, i32 %y)</tt>.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6874
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]6875</div>
6876
6877<!-- _______________________________________________________________________ -->
6878<div class="doc_subsubsection">
6879 <a name="int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a>
6880</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6881
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]6882<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6883
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]6884<h5>Syntax:</h5>
6885<pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6886 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]6887</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6888
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]6889<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6890<p>This fills the memory pointed to by <tt>tramp</tt> with code and returns a
6891 function pointer suitable for executing it.</p>
6892
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]6893<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6894<p>The <tt>llvm.init.trampoline</tt> intrinsic takes three arguments, all
6895 pointers. The <tt>tramp</tt> argument must point to a sufficiently large and
6896 sufficiently aligned block of memory; this memory is written to by the
6897 intrinsic. Note that the size and the alignment are target-specific - LLVM
6898 currently provides no portable way of determining them, so a front-end that
6899 generates this intrinsic needs to have some target-specific knowledge.
6900 The <tt>func</tt> argument must hold a function bitcast to
6901 an <tt>i8*</tt>.</p>
6902
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]6903<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6904<p>The block of memory pointed to by <tt>tramp</tt> is filled with target
6905 dependent code, turning it into a function. A pointer to this function is
6906 returned, but needs to be bitcast to an <a href="#int_trampoline">appropriate
6907 function pointer type</a> before being called. The new function's signature
6908 is the same as that of <tt>func</tt> with any arguments marked with
6909 the <tt>nest</tt> attribute removed. At most one such <tt>nest</tt> argument
6910 is allowed, and it must be of pointer type. Calling the new function is
6911 equivalent to calling <tt>func</tt> with the same argument list, but
6912 with <tt>nval</tt> used for the missing <tt>nest</tt> argument. If, after
6913 calling <tt>llvm.init.trampoline</tt>, the memory pointed to
6914 by <tt>tramp</tt> is modified, then the effect of any later call to the
6915 returned function pointer is undefined.</p>
6916
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]6917</div>
6918
6919<!-- ======================================================================= -->
6920<div class="doc_subsection">
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]6921 <a name="int_atomics">Atomic Operations and Synchronization Intrinsics</a>
6922</div>
6923
6924<div class="doc_text">
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]6925
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6926<p>These intrinsic functions expand the "universal IR" of LLVM to represent
6927 hardware constructs for atomic operations and memory synchronization. This
6928 provides an interface to the hardware, not an interface to the programmer. It
6929 is aimed at a low enough level to allow any programming models or APIs
6930 (Application Programming Interfaces) which need atomic behaviors to map
6931 cleanly onto it. It is also modeled primarily on hardware behavior. Just as
6932 hardware provides a "universal IR" for source languages, it also provides a
6933 starting point for developing a "universal" atomic operation and
6934 synchronization IR.</p>
6935
6936<p>These do <em>not</em> form an API such as high-level threading libraries,
6937 software transaction memory systems, atomic primitives, and intrinsic
6938 functions as found in BSD, GNU libc, atomic_ops, APR, and other system and
6939 application libraries. The hardware interface provided by LLVM should allow
6940 a clean implementation of all of these APIs and parallel programming models.
6941 No one model or paradigm should be selected above others unless the hardware
6942 itself ubiquitously does so.</p>
6943
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]6944</div>
6945
6946<!-- _______________________________________________________________________ -->
6947<div class="doc_subsubsection">
6948 <a name="int_memory_barrier">'<tt>llvm.memory.barrier</tt>' Intrinsic</a>
6949</div>
6950<div class="doc_text">
6951<h5>Syntax:</h5>
6952<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]6953 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]6954</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6955
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]6956<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6957<p>The <tt>llvm.memory.barrier</tt> intrinsic guarantees ordering between
6958 specific pairs of memory access types.</p>
6959
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]6960<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6961<p>The <tt>llvm.memory.barrier</tt> intrinsic requires five boolean arguments.
6962 The first four arguments enables a specific barrier as listed below. The
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]6963 fifth argument specifies that the barrier applies to io or device or uncached
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6964 memory.</p>
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]6965
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6966<ul>
6967 <li><tt>ll</tt>: load-load barrier</li>
6968 <li><tt>ls</tt>: load-store barrier</li>
6969 <li><tt>sl</tt>: store-load barrier</li>
6970 <li><tt>ss</tt>: store-store barrier</li>
6971 <li><tt>device</tt>: barrier applies to device and uncached memory also.</li>
6972</ul>
6973
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]6974<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6975<p>This intrinsic causes the system to enforce some ordering constraints upon
6976 the loads and stores of the program. This barrier does not
6977 indicate <em>when</em> any events will occur, it only enforces
6978 an <em>order</em> in which they occur. For any of the specified pairs of load
6979 and store operations (f.ex. load-load, or store-load), all of the first
6980 operations preceding the barrier will complete before any of the second
6981 operations succeeding the barrier begin. Specifically the semantics for each
6982 pairing is as follows:</p>
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]6983
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6984<ul>
6985 <li><tt>ll</tt>: All loads before the barrier must complete before any load
6986 after the barrier begins.</li>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]6987 <li><tt>ls</tt>: All loads before the barrier must complete before any
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6988 store after the barrier begins.</li>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]6989 <li><tt>ss</tt>: All stores before the barrier must complete before any
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6990 store after the barrier begins.</li>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]6991 <li><tt>sl</tt>: All stores before the barrier must complete before any
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6992 load after the barrier begins.</li>
6993</ul>
6994
6995<p>These semantics are applied with a logical "and" behavior when more than one
6996 is enabled in a single memory barrier intrinsic.</p>
6997
6998<p>Backends may implement stronger barriers than those requested when they do
6999 not support as fine grained a barrier as requested. Some architectures do
7000 not need all types of barriers and on such architectures, these become
7001 noops.</p>
7002
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7003<h5>Example:</h5>
7004<pre>
Victor Hernandeza70c6df2009-10-26 23:44:29 +0000[diff] [blame]7005%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7006%ptr = bitcast i8* %mallocP to i32*
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7007 store i32 4, %ptr
7008
7009%result1 = load i32* %ptr <i>; yields {i32}:result1 = 4</i>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7010 call void @llvm.memory.barrier(i1 false, i1 true, i1 false, i1 false)
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7011 <i>; guarantee the above finishes</i>
7012 store i32 8, %ptr <i>; before this begins</i>
7013</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7014
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7015</div>
7016
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7017<!-- _______________________________________________________________________ -->
7018<div class="doc_subsubsection">
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7019 <a name="int_atomic_cmp_swap">'<tt>llvm.atomic.cmp.swap.*</tt>' Intrinsic</a>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7020</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7021
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7022<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7023
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7024<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7025<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.cmp.swap</tt> on
7026 any integer bit width and for different address spaces. Not all targets
7027 support all bit widths however.</p>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7028
7029<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7030 declare i8 @llvm.atomic.cmp.swap.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;cmp&gt;, i8 &lt;val&gt;)
7031 declare i16 @llvm.atomic.cmp.swap.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;cmp&gt;, i16 &lt;val&gt;)
7032 declare i32 @llvm.atomic.cmp.swap.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;cmp&gt;, i32 &lt;val&gt;)
7033 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]7034</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7035
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7036<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7037<p>This loads a value in memory and compares it to a given value. If they are
7038 equal, it stores a new value into the memory.</p>
7039
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7040<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7041<p>The <tt>llvm.atomic.cmp.swap</tt> intrinsic takes three arguments. The result
7042 as well as both <tt>cmp</tt> and <tt>val</tt> must be integer values with the
7043 same bit width. The <tt>ptr</tt> argument must be a pointer to a value of
7044 this integer type. While any bit width integer may be used, targets may only
7045 lower representations they support in hardware.</p>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7046
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7047<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7048<p>This entire intrinsic must be executed atomically. It first loads the value
7049 in memory pointed to by <tt>ptr</tt> and compares it with the
7050 value <tt>cmp</tt>. If they are equal, <tt>val</tt> is stored into the
7051 memory. The loaded value is yielded in all cases. This provides the
7052 equivalent of an atomic compare-and-swap operation within the SSA
7053 framework.</p>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7054
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7055<h5>Examples:</h5>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7056<pre>
Victor Hernandeza70c6df2009-10-26 23:44:29 +0000[diff] [blame]7057%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7058%ptr = bitcast i8* %mallocP to i32*
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7059 store i32 4, %ptr
7060
7061%val1 = add i32 4, 4
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7062%result1 = call i32 @llvm.atomic.cmp.swap.i32.p0i32(i32* %ptr, i32 4, %val1)
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7063 <i>; yields {i32}:result1 = 4</i>
7064%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
7065%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
7066
7067%val2 = add i32 1, 1
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7068%result2 = call i32 @llvm.atomic.cmp.swap.i32.p0i32(i32* %ptr, i32 5, %val2)
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7069 <i>; yields {i32}:result2 = 8</i>
7070%stored2 = icmp eq i32 %result2, 5 <i>; yields {i1}:stored2 = false</i>
7071
7072%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 8</i>
7073</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7074
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7075</div>
7076
7077<!-- _______________________________________________________________________ -->
7078<div class="doc_subsubsection">
7079 <a name="int_atomic_swap">'<tt>llvm.atomic.swap.*</tt>' Intrinsic</a>
7080</div>
7081<div class="doc_text">
7082<h5>Syntax:</h5>
7083
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7084<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.swap</tt> on any
7085 integer bit width. Not all targets support all bit widths however.</p>
7086
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7087<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7088 declare i8 @llvm.atomic.swap.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;val&gt;)
7089 declare i16 @llvm.atomic.swap.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;val&gt;)
7090 declare i32 @llvm.atomic.swap.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;val&gt;)
7091 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]7092</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7093
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7094<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7095<p>This intrinsic loads the value stored in memory at <tt>ptr</tt> and yields
7096 the value from memory. It then stores the value in <tt>val</tt> in the memory
7097 at <tt>ptr</tt>.</p>
7098
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7099<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7100<p>The <tt>llvm.atomic.swap</tt> intrinsic takes two arguments. Both
7101 the <tt>val</tt> argument and the result must be integers of the same bit
7102 width. The first argument, <tt>ptr</tt>, must be a pointer to a value of this
7103 integer type. The targets may only lower integer representations they
7104 support.</p>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7105
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7106<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7107<p>This intrinsic loads the value pointed to by <tt>ptr</tt>, yields it, and
7108 stores <tt>val</tt> back into <tt>ptr</tt> atomically. This provides the
7109 equivalent of an atomic swap operation within the SSA framework.</p>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7110
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7111<h5>Examples:</h5>
7112<pre>
Victor Hernandeza70c6df2009-10-26 23:44:29 +0000[diff] [blame]7113%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7114%ptr = bitcast i8* %mallocP to i32*
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7115 store i32 4, %ptr
7116
7117%val1 = add i32 4, 4
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7118%result1 = call i32 @llvm.atomic.swap.i32.p0i32(i32* %ptr, i32 %val1)
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7119 <i>; yields {i32}:result1 = 4</i>
7120%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
7121%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
7122
7123%val2 = add i32 1, 1
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7124%result2 = call i32 @llvm.atomic.swap.i32.p0i32(i32* %ptr, i32 %val2)
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7125 <i>; yields {i32}:result2 = 8</i>
7126
7127%stored2 = icmp eq i32 %result2, 8 <i>; yields {i1}:stored2 = true</i>
7128%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 2</i>
7129</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7130
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7131</div>
7132
7133<!-- _______________________________________________________________________ -->
7134<div class="doc_subsubsection">
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7135 <a name="int_atomic_load_add">'<tt>llvm.atomic.load.add.*</tt>' Intrinsic</a>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7136
7137</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7138
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7139<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7140
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7141<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7142<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.load.add</tt> on
7143 any integer bit width. Not all targets support all bit widths however.</p>
7144
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7145<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7146 declare i8 @llvm.atomic.load.add.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7147 declare i16 @llvm.atomic.load.add.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7148 declare i32 @llvm.atomic.load.add.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7149 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]7150</pre>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7151
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7152<h5>Overview:</h5>
7153<p>This intrinsic adds <tt>delta</tt> to the value stored in memory
7154 at <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.</p>
7155
7156<h5>Arguments:</h5>
7157<p>The intrinsic takes two arguments, the first a pointer to an integer value
7158 and the second an integer value. The result is also an integer value. These
7159 integer types can have any bit width, but they must all have the same bit
7160 width. The targets may only lower integer representations they support.</p>
7161
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7162<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7163<p>This intrinsic does a series of operations atomically. It first loads the
7164 value stored at <tt>ptr</tt>. It then adds <tt>delta</tt>, stores the result
7165 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]7166
7167<h5>Examples:</h5>
7168<pre>
Victor Hernandeza70c6df2009-10-26 23:44:29 +0000[diff] [blame]7169%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7170%ptr = bitcast i8* %mallocP to i32*
7171 store i32 4, %ptr
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7172%result1 = call i32 @llvm.atomic.load.add.i32.p0i32(i32* %ptr, i32 4)
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7173 <i>; yields {i32}:result1 = 4</i>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7174%result2 = call i32 @llvm.atomic.load.add.i32.p0i32(i32* %ptr, i32 2)
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7175 <i>; yields {i32}:result2 = 8</i>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7176%result3 = call i32 @llvm.atomic.load.add.i32.p0i32(i32* %ptr, i32 5)
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7177 <i>; yields {i32}:result3 = 10</i>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7178%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 15</i>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7179</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7180
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7181</div>
7182
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7183<!-- _______________________________________________________________________ -->
7184<div class="doc_subsubsection">
7185 <a name="int_atomic_load_sub">'<tt>llvm.atomic.load.sub.*</tt>' Intrinsic</a>
7186
7187</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7188
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7189<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7190
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7191<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7192<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.load.sub</tt> on
7193 any integer bit width and for different address spaces. Not all targets
7194 support all bit widths however.</p>
7195
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7196<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7197 declare i8 @llvm.atomic.load.sub.i8.p0i32(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7198 declare i16 @llvm.atomic.load.sub.i16.p0i32(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7199 declare i32 @llvm.atomic.load.sub.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7200 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]7201</pre>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7202
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7203<h5>Overview:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]7204<p>This intrinsic subtracts <tt>delta</tt> to the value stored in memory at
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7205 <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.</p>
7206
7207<h5>Arguments:</h5>
7208<p>The intrinsic takes two arguments, the first a pointer to an integer value
7209 and the second an integer value. The result is also an integer value. These
7210 integer types can have any bit width, but they must all have the same bit
7211 width. The targets may only lower integer representations they support.</p>
7212
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7213<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7214<p>This intrinsic does a series of operations atomically. It first loads the
7215 value stored at <tt>ptr</tt>. It then subtracts <tt>delta</tt>, stores the
7216 result to <tt>ptr</tt>. It yields the original value stored
7217 at <tt>ptr</tt>.</p>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7218
7219<h5>Examples:</h5>
7220<pre>
Victor Hernandeza70c6df2009-10-26 23:44:29 +0000[diff] [blame]7221%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7222%ptr = bitcast i8* %mallocP to i32*
7223 store i32 8, %ptr
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7224%result1 = call i32 @llvm.atomic.load.sub.i32.p0i32(i32* %ptr, i32 4)
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7225 <i>; yields {i32}:result1 = 8</i>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7226%result2 = call i32 @llvm.atomic.load.sub.i32.p0i32(i32* %ptr, i32 2)
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7227 <i>; yields {i32}:result2 = 4</i>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7228%result3 = call i32 @llvm.atomic.load.sub.i32.p0i32(i32* %ptr, i32 5)
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7229 <i>; yields {i32}:result3 = 2</i>
7230%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = -3</i>
7231</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7232
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7233</div>
7234
7235<!-- _______________________________________________________________________ -->
7236<div class="doc_subsubsection">
7237 <a name="int_atomic_load_and">'<tt>llvm.atomic.load.and.*</tt>' Intrinsic</a><br>
7238 <a name="int_atomic_load_nand">'<tt>llvm.atomic.load.nand.*</tt>' Intrinsic</a><br>
7239 <a name="int_atomic_load_or">'<tt>llvm.atomic.load.or.*</tt>' Intrinsic</a><br>
7240 <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]7241</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7242
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7243<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7244
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7245<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7246<p>These are overloaded intrinsics. You can
7247 use <tt>llvm.atomic.load_and</tt>, <tt>llvm.atomic.load_nand</tt>,
7248 <tt>llvm.atomic.load_or</tt>, and <tt>llvm.atomic.load_xor</tt> on any integer
7249 bit width and for different address spaces. Not all targets support all bit
7250 widths however.</p>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7251
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7252<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7253 declare i8 @llvm.atomic.load.and.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7254 declare i16 @llvm.atomic.load.and.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7255 declare i32 @llvm.atomic.load.and.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7256 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]7257</pre>
7258
7259<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7260 declare i8 @llvm.atomic.load.or.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7261 declare i16 @llvm.atomic.load.or.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7262 declare i32 @llvm.atomic.load.or.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7263 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]7264</pre>
7265
7266<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7267 declare i8 @llvm.atomic.load.nand.i8.p0i32(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7268 declare i16 @llvm.atomic.load.nand.i16.p0i32(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7269 declare i32 @llvm.atomic.load.nand.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7270 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]7271</pre>
7272
7273<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7274 declare i8 @llvm.atomic.load.xor.i8.p0i32(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7275 declare i16 @llvm.atomic.load.xor.i16.p0i32(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7276 declare i32 @llvm.atomic.load.xor.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7277 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]7278</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7279
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7280<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7281<p>These intrinsics bitwise the operation (and, nand, or, xor) <tt>delta</tt> to
7282 the value stored in memory at <tt>ptr</tt>. It yields the original value
7283 at <tt>ptr</tt>.</p>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7284
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7285<h5>Arguments:</h5>
7286<p>These intrinsics take two arguments, the first a pointer to an integer value
7287 and the second an integer value. The result is also an integer value. These
7288 integer types can have any bit width, but they must all have the same bit
7289 width. The targets may only lower integer representations they support.</p>
7290
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7291<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7292<p>These intrinsics does a series of operations atomically. They first load the
7293 value stored at <tt>ptr</tt>. They then do the bitwise
7294 operation <tt>delta</tt>, store the result to <tt>ptr</tt>. They yield the
7295 original value stored at <tt>ptr</tt>.</p>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7296
7297<h5>Examples:</h5>
7298<pre>
Victor Hernandeza70c6df2009-10-26 23:44:29 +0000[diff] [blame]7299%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7300%ptr = bitcast i8* %mallocP to i32*
7301 store i32 0x0F0F, %ptr
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7302%result0 = call i32 @llvm.atomic.load.nand.i32.p0i32(i32* %ptr, i32 0xFF)
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7303 <i>; yields {i32}:result0 = 0x0F0F</i>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7304%result1 = call i32 @llvm.atomic.load.and.i32.p0i32(i32* %ptr, i32 0xFF)
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7305 <i>; yields {i32}:result1 = 0xFFFFFFF0</i>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7306%result2 = call i32 @llvm.atomic.load.or.i32.p0i32(i32* %ptr, i32 0F)
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7307 <i>; yields {i32}:result2 = 0xF0</i>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7308%result3 = call i32 @llvm.atomic.load.xor.i32.p0i32(i32* %ptr, i32 0F)
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7309 <i>; yields {i32}:result3 = FF</i>
7310%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = F0</i>
7311</pre>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7312
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7313</div>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7314
7315<!-- _______________________________________________________________________ -->
7316<div class="doc_subsubsection">
7317 <a name="int_atomic_load_max">'<tt>llvm.atomic.load.max.*</tt>' Intrinsic</a><br>
7318 <a name="int_atomic_load_min">'<tt>llvm.atomic.load.min.*</tt>' Intrinsic</a><br>
7319 <a name="int_atomic_load_umax">'<tt>llvm.atomic.load.umax.*</tt>' Intrinsic</a><br>
7320 <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]7321</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7322
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7323<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7324
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7325<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7326<p>These are overloaded intrinsics. You can use <tt>llvm.atomic.load_max</tt>,
7327 <tt>llvm.atomic.load_min</tt>, <tt>llvm.atomic.load_umax</tt>, and
7328 <tt>llvm.atomic.load_umin</tt> on any integer bit width and for different
7329 address spaces. Not all targets support all bit widths however.</p>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7330
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7331<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7332 declare i8 @llvm.atomic.load.max.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7333 declare i16 @llvm.atomic.load.max.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7334 declare i32 @llvm.atomic.load.max.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7335 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]7336</pre>
7337
7338<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7339 declare i8 @llvm.atomic.load.min.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7340 declare i16 @llvm.atomic.load.min.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7341 declare i32 @llvm.atomic.load.min.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7342 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]7343</pre>
7344
7345<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7346 declare i8 @llvm.atomic.load.umax.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7347 declare i16 @llvm.atomic.load.umax.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7348 declare i32 @llvm.atomic.load.umax.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7349 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]7350</pre>
7351
7352<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7353 declare i8 @llvm.atomic.load.umin.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7354 declare i16 @llvm.atomic.load.umin.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7355 declare i32 @llvm.atomic.load.umin.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7356 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]7357</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7358
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7359<h5>Overview:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]7360<p>These intrinsics takes the signed or unsigned minimum or maximum of
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7361 <tt>delta</tt> and the value stored in memory at <tt>ptr</tt>. It yields the
7362 original value at <tt>ptr</tt>.</p>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7363
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7364<h5>Arguments:</h5>
7365<p>These intrinsics take two arguments, the first a pointer to an integer value
7366 and the second an integer value. The result is also an integer value. These
7367 integer types can have any bit width, but they must all have the same bit
7368 width. The targets may only lower integer representations they support.</p>
7369
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7370<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7371<p>These intrinsics does a series of operations atomically. They first load the
7372 value stored at <tt>ptr</tt>. They then do the signed or unsigned min or
7373 max <tt>delta</tt> and the value, store the result to <tt>ptr</tt>. They
7374 yield the original value stored at <tt>ptr</tt>.</p>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7375
7376<h5>Examples:</h5>
7377<pre>
Victor Hernandeza70c6df2009-10-26 23:44:29 +0000[diff] [blame]7378%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7379%ptr = bitcast i8* %mallocP to i32*
7380 store i32 7, %ptr
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7381%result0 = call i32 @llvm.atomic.load.min.i32.p0i32(i32* %ptr, i32 -2)
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7382 <i>; yields {i32}:result0 = 7</i>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7383%result1 = call i32 @llvm.atomic.load.max.i32.p0i32(i32* %ptr, i32 8)
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7384 <i>; yields {i32}:result1 = -2</i>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7385%result2 = call i32 @llvm.atomic.load.umin.i32.p0i32(i32* %ptr, i32 10)
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7386 <i>; yields {i32}:result2 = 8</i>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7387%result3 = call i32 @llvm.atomic.load.umax.i32.p0i32(i32* %ptr, i32 30)
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7388 <i>; yields {i32}:result3 = 8</i>
7389%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 30</i>
7390</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7391
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7392</div>
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7393
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]7394
7395<!-- ======================================================================= -->
7396<div class="doc_subsection">
7397 <a name="int_memorymarkers">Memory Use Markers</a>
7398</div>
7399
7400<div class="doc_text">
7401
7402<p>This class of intrinsics exists to information about the lifetime of memory
7403 objects and ranges where variables are immutable.</p>
7404
7405</div>
7406
7407<!-- _______________________________________________________________________ -->
7408<div class="doc_subsubsection">
7409 <a name="int_lifetime_start">'<tt>llvm.lifetime.start</tt>' Intrinsic</a>
7410</div>
7411
7412<div class="doc_text">
7413
7414<h5>Syntax:</h5>
7415<pre>
7416 declare void @llvm.lifetime.start(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7417</pre>
7418
7419<h5>Overview:</h5>
7420<p>The '<tt>llvm.lifetime.start</tt>' intrinsic specifies the start of a memory
7421 object's lifetime.</p>
7422
7423<h5>Arguments:</h5>
Nick Lewycky9bc89042009-10-13 07:57:33 +0000[diff] [blame]7424<p>The first argument is a constant integer representing the size of the
7425 object, or -1 if it is variable sized. The second argument is a pointer to
7426 the object.</p>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]7427
7428<h5>Semantics:</h5>
7429<p>This intrinsic indicates that before this point in the code, the value of the
7430 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]7431 never be used and has an undefined value. A load from the pointer that
7432 precedes this intrinsic can be replaced with
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]7433 <tt>'<a href="#undefvalues">undef</a>'</tt>.</p>
7434
7435</div>
7436
7437<!-- _______________________________________________________________________ -->
7438<div class="doc_subsubsection">
7439 <a name="int_lifetime_end">'<tt>llvm.lifetime.end</tt>' Intrinsic</a>
7440</div>
7441
7442<div class="doc_text">
7443
7444<h5>Syntax:</h5>
7445<pre>
7446 declare void @llvm.lifetime.end(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7447</pre>
7448
7449<h5>Overview:</h5>
7450<p>The '<tt>llvm.lifetime.end</tt>' intrinsic specifies the end of a memory
7451 object's lifetime.</p>
7452
7453<h5>Arguments:</h5>
Nick Lewycky9bc89042009-10-13 07:57:33 +0000[diff] [blame]7454<p>The first argument is a constant integer representing the size of the
7455 object, or -1 if it is variable sized. The second argument is a pointer to
7456 the object.</p>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]7457
7458<h5>Semantics:</h5>
7459<p>This intrinsic indicates that after this point in the code, the value of the
7460 memory pointed to by <tt>ptr</tt> is dead. This means that it is known to
7461 never be used and has an undefined value. Any stores into the memory object
7462 following this intrinsic may be removed as dead.
7463
7464</div>
7465
7466<!-- _______________________________________________________________________ -->
7467<div class="doc_subsubsection">
7468 <a name="int_invariant_start">'<tt>llvm.invariant.start</tt>' Intrinsic</a>
7469</div>
7470
7471<div class="doc_text">
7472
7473<h5>Syntax:</h5>
7474<pre>
7475 declare {}* @llvm.invariant.start(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;) readonly
7476</pre>
7477
7478<h5>Overview:</h5>
7479<p>The '<tt>llvm.invariant.start</tt>' intrinsic specifies that the contents of
7480 a memory object will not change.</p>
7481
7482<h5>Arguments:</h5>
Nick Lewycky9bc89042009-10-13 07:57:33 +0000[diff] [blame]7483<p>The first argument is a constant integer representing the size of the
7484 object, or -1 if it is variable sized. The second argument is a pointer to
7485 the object.</p>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]7486
7487<h5>Semantics:</h5>
7488<p>This intrinsic indicates that until an <tt>llvm.invariant.end</tt> that uses
7489 the return value, the referenced memory location is constant and
7490 unchanging.</p>
7491
7492</div>
7493
7494<!-- _______________________________________________________________________ -->
7495<div class="doc_subsubsection">
7496 <a name="int_invariant_end">'<tt>llvm.invariant.end</tt>' Intrinsic</a>
7497</div>
7498
7499<div class="doc_text">
7500
7501<h5>Syntax:</h5>
7502<pre>
7503 declare void @llvm.invariant.end({}* &lt;start&gt;, i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7504</pre>
7505
7506<h5>Overview:</h5>
7507<p>The '<tt>llvm.invariant.end</tt>' intrinsic specifies that the contents of
7508 a memory object are mutable.</p>
7509
7510<h5>Arguments:</h5>
7511<p>The first argument is the matching <tt>llvm.invariant.start</tt> intrinsic.
Nick Lewycky9bc89042009-10-13 07:57:33 +0000[diff] [blame]7512 The second argument is a constant integer representing the size of the
7513 object, or -1 if it is variable sized and the third argument is a pointer
7514 to the object.</p>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]7515
7516<h5>Semantics:</h5>
7517<p>This intrinsic indicates that the memory is mutable again.</p>
7518
7519</div>
7520
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7521<!-- ======================================================================= -->
7522<div class="doc_subsection">
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]7523 <a name="int_general">General Intrinsics</a>
7524</div>
7525
7526<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7527
7528<p>This class of intrinsics is designed to be generic and has no specific
7529 purpose.</p>
7530
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]7531</div>
7532
7533<!-- _______________________________________________________________________ -->
7534<div class="doc_subsubsection">
7535 <a name="int_var_annotation">'<tt>llvm.var.annotation</tt>' Intrinsic</a>
7536</div>
7537
7538<div class="doc_text">
7539
7540<h5>Syntax:</h5>
7541<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7542 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]7543</pre>
7544
7545<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7546<p>The '<tt>llvm.var.annotation</tt>' intrinsic.</p>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]7547
7548<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7549<p>The first argument is a pointer to a value, the second is a pointer to a
7550 global string, the third is a pointer to a global string which is the source
7551 file name, and the last argument is the line number.</p>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]7552
7553<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7554<p>This intrinsic allows annotation of local variables with arbitrary strings.
7555 This can be useful for special purpose optimizations that want to look for
7556 these annotations. These have no other defined use, they are ignored by code
7557 generation and optimization.</p>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]7558
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]7559</div>
7560
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]7561<!-- _______________________________________________________________________ -->
7562<div class="doc_subsubsection">
Tanya Lattner0186a652007-09-21 23:57:59 +0000[diff] [blame]7563 <a name="int_annotation">'<tt>llvm.annotation.*</tt>' Intrinsic</a>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]7564</div>
7565
7566<div class="doc_text">
7567
7568<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7569<p>This is an overloaded intrinsic. You can use '<tt>llvm.annotation</tt>' on
7570 any integer bit width.</p>
7571
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]7572<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7573 declare i8 @llvm.annotation.i8(i8 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
7574 declare i16 @llvm.annotation.i16(i16 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
7575 declare i32 @llvm.annotation.i32(i32 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
7576 declare i64 @llvm.annotation.i64(i64 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
7577 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]7578</pre>
7579
7580<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7581<p>The '<tt>llvm.annotation</tt>' intrinsic.</p>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]7582
7583<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7584<p>The first argument is an integer value (result of some expression), the
7585 second is a pointer to a global string, the third is a pointer to a global
7586 string which is the source file name, and the last argument is the line
7587 number. It returns the value of the first argument.</p>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]7588
7589<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7590<p>This intrinsic allows annotations to be put on arbitrary expressions with
7591 arbitrary strings. This can be useful for special purpose optimizations that
7592 want to look for these annotations. These have no other defined use, they
7593 are ignored by code generation and optimization.</p>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]7594
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]7595</div>
Jim Laskey2211f492007-03-14 19:31:19 +0000[diff] [blame]7596
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]7597<!-- _______________________________________________________________________ -->
7598<div class="doc_subsubsection">
7599 <a name="int_trap">'<tt>llvm.trap</tt>' Intrinsic</a>
7600</div>
7601
7602<div class="doc_text">
7603
7604<h5>Syntax:</h5>
7605<pre>
7606 declare void @llvm.trap()
7607</pre>
7608
7609<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7610<p>The '<tt>llvm.trap</tt>' intrinsic.</p>
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]7611
7612<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7613<p>None.</p>
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]7614
7615<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7616<p>This intrinsics is lowered to the target dependent trap instruction. If the
7617 target does not have a trap instruction, this intrinsic will be lowered to
7618 the call of the <tt>abort()</tt> function.</p>
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]7619
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]7620</div>
7621
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]7622<!-- _______________________________________________________________________ -->
7623<div class="doc_subsubsection">
Misha Brukman50de2b22008-11-22 23:55:29 +0000[diff] [blame]7624 <a name="int_stackprotector">'<tt>llvm.stackprotector</tt>' Intrinsic</a>
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]7625</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7626
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]7627<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7628
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]7629<h5>Syntax:</h5>
7630<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7631 declare void @llvm.stackprotector(i8* &lt;guard&gt;, i8** &lt;slot&gt;)
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]7632</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7633
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]7634<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7635<p>The <tt>llvm.stackprotector</tt> intrinsic takes the <tt>guard</tt> and
7636 stores it onto the stack at <tt>slot</tt>. The stack slot is adjusted to
7637 ensure that it is placed on the stack before local variables.</p>
7638
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]7639<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7640<p>The <tt>llvm.stackprotector</tt> intrinsic requires two pointer
7641 arguments. The first argument is the value loaded from the stack
7642 guard <tt>@__stack_chk_guard</tt>. The second variable is an <tt>alloca</tt>
7643 that has enough space to hold the value of the guard.</p>
7644
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]7645<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7646<p>This intrinsic causes the prologue/epilogue inserter to force the position of
7647 the <tt>AllocaInst</tt> stack slot to be before local variables on the
7648 stack. This is to ensure that if a local variable on the stack is
7649 overwritten, it will destroy the value of the guard. When the function exits,
7650 the guard on the stack is checked against the original guard. If they're
7651 different, then the program aborts by calling the <tt>__stack_chk_fail()</tt>
7652 function.</p>
7653
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]7654</div>
7655
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]7656<!-- _______________________________________________________________________ -->
7657<div class="doc_subsubsection">
7658 <a name="int_objectsize">'<tt>llvm.objectsize</tt>' Intrinsic</a>
7659</div>
7660
7661<div class="doc_text">
7662
7663<h5>Syntax:</h5>
7664<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7665 declare i32 @llvm.objectsize.i32(i8* &lt;object&gt;, i1 &lt;type&gt;)
7666 declare i64 @llvm.objectsize.i64(i8* &lt;object&gt;, i1 &lt;type&gt;)
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]7667</pre>
7668
7669<h5>Overview:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]7670<p>The <tt>llvm.objectsize</tt> intrinsic is designed to provide information
Eric Christopher3070e162010-01-08 21:42:39 +0000[diff] [blame]7671 to the optimizers to discover at compile time either a) when an
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]7672 operation like memcpy will either overflow a buffer that corresponds to
7673 an object, or b) to determine that a runtime check for overflow isn't
7674 necessary. An object in this context means an allocation of a
Eric Christopher31e39bd2009-12-23 00:29:49 +0000[diff] [blame]7675 specific class, structure, array, or other object.</p>
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]7676
7677<h5>Arguments:</h5>
7678<p>The <tt>llvm.objectsize</tt> intrinsic takes two arguments. The first
Eric Christopher31e39bd2009-12-23 00:29:49 +0000[diff] [blame]7679 argument is a pointer to or into the <tt>object</tt>. The second argument
7680 is a boolean 0 or 1. This argument determines whether you want the
7681 maximum (0) or minimum (1) bytes remaining. This needs to be a literal 0 or
7682 1, variables are not allowed.</p>
7683
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]7684<h5>Semantics:</h5>
7685<p>The <tt>llvm.objectsize</tt> intrinsic is lowered to either a constant
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]7686 representing the size of the object concerned or <tt>i32/i64 -1 or 0</tt>
7687 (depending on the <tt>type</tt> argument if the size cannot be determined
7688 at compile time.</p>
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]7689
7690</div>
7691
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]7692<!-- *********************************************************************** -->
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]7693<hr>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]7694<address>
7695 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
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Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]7699
7700 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
Reid Spencerca058542006-03-14 05:39:39 +0000[diff] [blame]7701 <a href="http://llvm.org">The LLVM Compiler Infrastructure</a><br>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]7702 Last modified: $Date$
7703</address>
Chris Lattnerb8f816e2008-01-04 04:33:49 +0000[diff] [blame]7704
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]7705</body>
7706</html>