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gerrit-public.fairphone.software / toolchain / llvm-project / 35315d065b74537c1290767d0b8da9ca2036fdea / . / llvm / docs / LangRef.html
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4<head>
5 <title>LLVM Assembly Language Reference Manual</title>
Reid Spencercb84e432004-08-26 20:44:00 +0000[diff] [blame]6 <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
7 <meta name="author" content="Chris Lattner">
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]8 <meta name="description"
Reid Spencercb84e432004-08-26 20:44:00 +0000[diff] [blame]9 content="LLVM Assembly Language Reference Manual.">
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]10 <link rel="stylesheet" href="llvm.css" type="text/css">
11</head>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]12
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]13<body>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]14
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]15<div class="doc_title"> LLVM Language Reference Manual </div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]16<ol>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]17 <li><a href="#abstract">Abstract</a></li>
18 <li><a href="#introduction">Introduction</a></li>
19 <li><a href="#identifiers">Identifiers</a></li>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]20 <li><a href="#highlevel">High Level Structure</a>
21 <ol>
22 <li><a href="#modulestructure">Module Structure</a></li>
Bill Wendlinga3c6f6b2009-07-20 01:03:30 +0000[diff] [blame]23 <li><a href="#linkage">Linkage Types</a>
24 <ol>
Bill Wendling8693ef82009-07-20 02:41:50 +0000[diff] [blame]25 <li><a href="#linkage_private">'<tt>private</tt>' Linkage</a></li>
26 <li><a href="#linkage_linker_private">'<tt>linker_private</tt>' Linkage</a></li>
Bill Wendling03bcd6e2010-07-01 21:55:59 +0000[diff] [blame]27 <li><a href="#linkage_linker_private_weak">'<tt>linker_private_weak</tt>' Linkage</a></li>
Bill Wendling578ee402010-08-20 22:05:50 +0000[diff] [blame]28 <li><a href="#linkage_linker_private_weak_def_auto">'<tt>linker_private_weak_def_auto</tt>' Linkage</a></li>
Bill Wendling8693ef82009-07-20 02:41:50 +0000[diff] [blame]29 <li><a href="#linkage_internal">'<tt>internal</tt>' Linkage</a></li>
30 <li><a href="#linkage_available_externally">'<tt>available_externally</tt>' Linkage</a></li>
31 <li><a href="#linkage_linkonce">'<tt>linkonce</tt>' Linkage</a></li>
32 <li><a href="#linkage_common">'<tt>common</tt>' Linkage</a></li>
33 <li><a href="#linkage_weak">'<tt>weak</tt>' Linkage</a></li>
34 <li><a href="#linkage_appending">'<tt>appending</tt>' Linkage</a></li>
35 <li><a href="#linkage_externweak">'<tt>extern_weak</tt>' Linkage</a></li>
Chris Lattner80d73c72009-10-10 18:26:06 +0000[diff] [blame]36 <li><a href="#linkage_linkonce_odr">'<tt>linkonce_odr</tt>' Linkage</a></li>
Bill Wendling8693ef82009-07-20 02:41:50 +0000[diff] [blame]37 <li><a href="#linkage_weak">'<tt>weak_odr</tt>' Linkage</a></li>
38 <li><a href="#linkage_external">'<tt>externally visible</tt>' Linkage</a></li>
39 <li><a href="#linkage_dllimport">'<tt>dllimport</tt>' Linkage</a></li>
40 <li><a href="#linkage_dllexport">'<tt>dllexport</tt>' Linkage</a></li>
Bill Wendlinga3c6f6b2009-07-20 01:03:30 +0000[diff] [blame]41 </ol>
42 </li>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]43 <li><a href="#callingconv">Calling Conventions</a></li>
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]44 <li><a href="#namedtypes">Named Types</a></li>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]45 <li><a href="#globalvars">Global Variables</a></li>
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]46 <li><a href="#functionstructure">Functions</a></li>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]47 <li><a href="#aliasstructure">Aliases</a></li>
Devang Pateld1a89692010-01-11 19:35:55 +0000[diff] [blame]48 <li><a href="#namedmetadatastructure">Named Metadata</a></li>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]49 <li><a href="#paramattrs">Parameter Attributes</a></li>
Devang Patel9eb525d2008-09-26 23:51:19 +0000[diff] [blame]50 <li><a href="#fnattrs">Function Attributes</a></li>
Gordon Henriksen71183b62007-12-10 03:18:06 +0000[diff] [blame]51 <li><a href="#gc">Garbage Collector Names</a></li>
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]52 <li><a href="#moduleasm">Module-Level Inline Assembly</a></li>
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]53 <li><a href="#datalayout">Data Layout</a></li>
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]54 <li><a href="#pointeraliasing">Pointer Aliasing Rules</a></li>
Jeffrey Yasskin5d284ae2010-04-26 21:21:24 +0000[diff] [blame]55 <li><a href="#volatile">Volatile Memory Accesses</a></li>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]56 </ol>
57 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]58 <li><a href="#typesystem">Type System</a>
59 <ol>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]60 <li><a href="#t_classifications">Type Classifications</a></li>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]61 <li><a href="#t_primitive">Primitive Types</a>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]62 <ol>
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]63 <li><a href="#t_integer">Integer Type</a></li>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]64 <li><a href="#t_floating">Floating Point Types</a></li>
Dale Johannesen33e5c352010-10-01 00:48:59 +0000[diff] [blame]65 <li><a href="#t_x86mmx">X86mmx Type</a></li>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]66 <li><a href="#t_void">Void Type</a></li>
67 <li><a href="#t_label">Label Type</a></li>
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]68 <li><a href="#t_metadata">Metadata Type</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]69 </ol>
70 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]71 <li><a href="#t_derived">Derived Types</a>
72 <ol>
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]73 <li><a href="#t_aggregate">Aggregate Types</a>
74 <ol>
75 <li><a href="#t_array">Array Type</a></li>
76 <li><a href="#t_struct">Structure Type</a></li>
77 <li><a href="#t_pstruct">Packed Structure Type</a></li>
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]78 <li><a href="#t_vector">Vector Type</a></li>
79 </ol>
80 </li>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]81 <li><a href="#t_function">Function Type</a></li>
82 <li><a href="#t_pointer">Pointer Type</a></li>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]83 <li><a href="#t_opaque">Opaque Type</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]84 </ol>
85 </li>
Chris Lattnercf7a5842009-02-02 07:32:36 +0000[diff] [blame]86 <li><a href="#t_uprefs">Type Up-references</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]87 </ol>
88 </li>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]89 <li><a href="#constants">Constants</a>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]90 <ol>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]91 <li><a href="#simpleconstants">Simple Constants</a></li>
Chris Lattner361bfcd2009-02-28 18:32:25 +0000[diff] [blame]92 <li><a href="#complexconstants">Complex Constants</a></li>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]93 <li><a href="#globalconstants">Global Variable and Function Addresses</a></li>
94 <li><a href="#undefvalues">Undefined Values</a></li>
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]95 <li><a href="#trapvalues">Trap Values</a></li>
Chris Lattner2bfd3202009-10-27 21:19:13 +0000[diff] [blame]96 <li><a href="#blockaddress">Addresses of Basic Blocks</a></li>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]97 <li><a href="#constantexprs">Constant Expressions</a></li>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]98 </ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]99 </li>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]100 <li><a href="#othervalues">Other Values</a>
101 <ol>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]102 <li><a href="#inlineasm">Inline Assembler Expressions</a></li>
Devang Pateld1a89692010-01-11 19:35:55 +0000[diff] [blame]103 <li><a href="#metadata">Metadata Nodes and Metadata Strings</a></li>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]104 </ol>
105 </li>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]106 <li><a href="#intrinsic_globals">Intrinsic Global Variables</a>
107 <ol>
108 <li><a href="#intg_used">The '<tt>llvm.used</tt>' Global Variable</a></li>
Chris Lattner58f9bb22009-07-20 06:14:25 +0000[diff] [blame]109 <li><a href="#intg_compiler_used">The '<tt>llvm.compiler.used</tt>'
110 Global Variable</a></li>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]111 <li><a href="#intg_global_ctors">The '<tt>llvm.global_ctors</tt>'
112 Global Variable</a></li>
113 <li><a href="#intg_global_dtors">The '<tt>llvm.global_dtors</tt>'
114 Global Variable</a></li>
115 </ol>
116 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]117 <li><a href="#instref">Instruction Reference</a>
118 <ol>
119 <li><a href="#terminators">Terminator Instructions</a>
120 <ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]121 <li><a href="#i_ret">'<tt>ret</tt>' Instruction</a></li>
122 <li><a href="#i_br">'<tt>br</tt>' Instruction</a></li>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]123 <li><a href="#i_switch">'<tt>switch</tt>' Instruction</a></li>
Chris Lattnerd04cb6d2009-10-28 00:19:10 +0000[diff] [blame]124 <li><a href="#i_indirectbr">'<tt>indirectbr</tt>' Instruction</a></li>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]125 <li><a href="#i_invoke">'<tt>invoke</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]126 <li><a href="#i_unwind">'<tt>unwind</tt>' Instruction</a></li>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]127 <li><a href="#i_unreachable">'<tt>unreachable</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]128 </ol>
129 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]130 <li><a href="#binaryops">Binary Operations</a>
131 <ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]132 <li><a href="#i_add">'<tt>add</tt>' Instruction</a></li>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]133 <li><a href="#i_fadd">'<tt>fadd</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]134 <li><a href="#i_sub">'<tt>sub</tt>' Instruction</a></li>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]135 <li><a href="#i_fsub">'<tt>fsub</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]136 <li><a href="#i_mul">'<tt>mul</tt>' Instruction</a></li>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]137 <li><a href="#i_fmul">'<tt>fmul</tt>' Instruction</a></li>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]138 <li><a href="#i_udiv">'<tt>udiv</tt>' Instruction</a></li>
139 <li><a href="#i_sdiv">'<tt>sdiv</tt>' Instruction</a></li>
140 <li><a href="#i_fdiv">'<tt>fdiv</tt>' Instruction</a></li>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]141 <li><a href="#i_urem">'<tt>urem</tt>' Instruction</a></li>
142 <li><a href="#i_srem">'<tt>srem</tt>' Instruction</a></li>
143 <li><a href="#i_frem">'<tt>frem</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]144 </ol>
145 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]146 <li><a href="#bitwiseops">Bitwise Binary Operations</a>
147 <ol>
Reid Spencer2ab01932007-02-02 13:57:07 +0000[diff] [blame]148 <li><a href="#i_shl">'<tt>shl</tt>' Instruction</a></li>
149 <li><a href="#i_lshr">'<tt>lshr</tt>' Instruction</a></li>
150 <li><a href="#i_ashr">'<tt>ashr</tt>' Instruction</a></li>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]151 <li><a href="#i_and">'<tt>and</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]152 <li><a href="#i_or">'<tt>or</tt>' Instruction</a></li>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]153 <li><a href="#i_xor">'<tt>xor</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]154 </ol>
155 </li>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]156 <li><a href="#vectorops">Vector Operations</a>
157 <ol>
158 <li><a href="#i_extractelement">'<tt>extractelement</tt>' Instruction</a></li>
159 <li><a href="#i_insertelement">'<tt>insertelement</tt>' Instruction</a></li>
160 <li><a href="#i_shufflevector">'<tt>shufflevector</tt>' Instruction</a></li>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]161 </ol>
162 </li>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]163 <li><a href="#aggregateops">Aggregate Operations</a>
164 <ol>
165 <li><a href="#i_extractvalue">'<tt>extractvalue</tt>' Instruction</a></li>
166 <li><a href="#i_insertvalue">'<tt>insertvalue</tt>' Instruction</a></li>
167 </ol>
168 </li>
Chris Lattner6ab66722006-08-15 00:45:58 +0000[diff] [blame]169 <li><a href="#memoryops">Memory Access and Addressing Operations</a>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]170 <ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]171 <li><a href="#i_alloca">'<tt>alloca</tt>' Instruction</a></li>
Robert Bocchino820bc75b2006-02-17 21:18:08 +0000[diff] [blame]172 <li><a href="#i_load">'<tt>load</tt>' Instruction</a></li>
173 <li><a href="#i_store">'<tt>store</tt>' Instruction</a></li>
174 <li><a href="#i_getelementptr">'<tt>getelementptr</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]175 </ol>
176 </li>
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]177 <li><a href="#convertops">Conversion Operations</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]178 <ol>
179 <li><a href="#i_trunc">'<tt>trunc .. to</tt>' Instruction</a></li>
180 <li><a href="#i_zext">'<tt>zext .. to</tt>' Instruction</a></li>
181 <li><a href="#i_sext">'<tt>sext .. to</tt>' Instruction</a></li>
182 <li><a href="#i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a></li>
183 <li><a href="#i_fpext">'<tt>fpext .. to</tt>' Instruction</a></li>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]184 <li><a href="#i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a></li>
185 <li><a href="#i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a></li>
186 <li><a href="#i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a></li>
187 <li><a href="#i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a></li>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]188 <li><a href="#i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a></li>
189 <li><a href="#i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a></li>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]190 <li><a href="#i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a></li>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]191 </ol>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]192 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]193 <li><a href="#otherops">Other Operations</a>
194 <ol>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]195 <li><a href="#i_icmp">'<tt>icmp</tt>' Instruction</a></li>
196 <li><a href="#i_fcmp">'<tt>fcmp</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]197 <li><a href="#i_phi">'<tt>phi</tt>' Instruction</a></li>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]198 <li><a href="#i_select">'<tt>select</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]199 <li><a href="#i_call">'<tt>call</tt>' Instruction</a></li>
Chris Lattner33337472006-01-13 23:26:01 +0000[diff] [blame]200 <li><a href="#i_va_arg">'<tt>va_arg</tt>' Instruction</a></li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]201 </ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]202 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]203 </ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]204 </li>
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]205 <li><a href="#intrinsics">Intrinsic Functions</a>
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]206 <ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]207 <li><a href="#int_varargs">Variable Argument Handling Intrinsics</a>
208 <ol>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]209 <li><a href="#int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a></li>
210 <li><a href="#int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a></li>
211 <li><a href="#int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]212 </ol>
213 </li>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]214 <li><a href="#int_gc">Accurate Garbage Collection Intrinsics</a>
215 <ol>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]216 <li><a href="#int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a></li>
217 <li><a href="#int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a></li>
218 <li><a href="#int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a></li>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]219 </ol>
220 </li>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]221 <li><a href="#int_codegen">Code Generator Intrinsics</a>
222 <ol>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]223 <li><a href="#int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a></li>
224 <li><a href="#int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a></li>
225 <li><a href="#int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a></li>
226 <li><a href="#int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a></li>
227 <li><a href="#int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a></li>
228 <li><a href="#int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a></li>
Dan Gohmane58f7b32010-05-26 21:56:15 +0000[diff] [blame]229 <li><a href="#int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a></li>
John Criswellaa1c3c12004-04-09 16:43:20 +0000[diff] [blame]230 </ol>
231 </li>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]232 <li><a href="#int_libc">Standard C Library Intrinsics</a>
233 <ol>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]234 <li><a href="#int_memcpy">'<tt>llvm.memcpy.*</tt>' Intrinsic</a></li>
235 <li><a href="#int_memmove">'<tt>llvm.memmove.*</tt>' Intrinsic</a></li>
236 <li><a href="#int_memset">'<tt>llvm.memset.*</tt>' Intrinsic</a></li>
237 <li><a href="#int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a></li>
238 <li><a href="#int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a></li>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]239 <li><a href="#int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a></li>
240 <li><a href="#int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a></li>
241 <li><a href="#int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a></li>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]242 </ol>
243 </li>
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]244 <li><a href="#int_manip">Bit Manipulation Intrinsics</a>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]245 <ol>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]246 <li><a href="#int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a></li>
Chris Lattnerb748c672006-01-16 22:34:14 +0000[diff] [blame]247 <li><a href="#int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic </a></li>
248 <li><a href="#int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic </a></li>
249 <li><a href="#int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic </a></li>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]250 </ol>
251 </li>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]252 <li><a href="#int_overflow">Arithmetic with Overflow Intrinsics</a>
253 <ol>
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]254 <li><a href="#int_sadd_overflow">'<tt>llvm.sadd.with.overflow.*</tt> Intrinsics</a></li>
255 <li><a href="#int_uadd_overflow">'<tt>llvm.uadd.with.overflow.*</tt> Intrinsics</a></li>
256 <li><a href="#int_ssub_overflow">'<tt>llvm.ssub.with.overflow.*</tt> Intrinsics</a></li>
257 <li><a href="#int_usub_overflow">'<tt>llvm.usub.with.overflow.*</tt> Intrinsics</a></li>
258 <li><a href="#int_smul_overflow">'<tt>llvm.smul.with.overflow.*</tt> Intrinsics</a></li>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]259 <li><a href="#int_umul_overflow">'<tt>llvm.umul.with.overflow.*</tt> Intrinsics</a></li>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]260 </ol>
261 </li>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]262 <li><a href="#int_fp16">Half Precision Floating Point Intrinsics</a>
263 <ol>
Chris Lattnerbbd8bd32010-03-14 23:03:31 +0000[diff] [blame]264 <li><a href="#int_convert_to_fp16">'<tt>llvm.convert.to.fp16</tt>' Intrinsic</a></li>
265 <li><a href="#int_convert_from_fp16">'<tt>llvm.convert.from.fp16</tt>' Intrinsic</a></li>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]266 </ol>
267 </li>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]268 <li><a href="#int_debugger">Debugger intrinsics</a></li>
Jim Laskey2211f492007-03-14 19:31:19 +0000[diff] [blame]269 <li><a href="#int_eh">Exception Handling intrinsics</a></li>
Duncan Sands86e01192007-09-11 14:10:23 +0000[diff] [blame]270 <li><a href="#int_trampoline">Trampoline Intrinsic</a>
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]271 <ol>
272 <li><a href="#int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a></li>
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]273 </ol>
274 </li>
Bill Wendlingf85850f2008-11-18 22:10:53 +0000[diff] [blame]275 <li><a href="#int_atomics">Atomic intrinsics</a>
276 <ol>
277 <li><a href="#int_memory_barrier"><tt>llvm.memory_barrier</tt></a></li>
278 <li><a href="#int_atomic_cmp_swap"><tt>llvm.atomic.cmp.swap</tt></a></li>
279 <li><a href="#int_atomic_swap"><tt>llvm.atomic.swap</tt></a></li>
280 <li><a href="#int_atomic_load_add"><tt>llvm.atomic.load.add</tt></a></li>
281 <li><a href="#int_atomic_load_sub"><tt>llvm.atomic.load.sub</tt></a></li>
282 <li><a href="#int_atomic_load_and"><tt>llvm.atomic.load.and</tt></a></li>
283 <li><a href="#int_atomic_load_nand"><tt>llvm.atomic.load.nand</tt></a></li>
284 <li><a href="#int_atomic_load_or"><tt>llvm.atomic.load.or</tt></a></li>
285 <li><a href="#int_atomic_load_xor"><tt>llvm.atomic.load.xor</tt></a></li>
286 <li><a href="#int_atomic_load_max"><tt>llvm.atomic.load.max</tt></a></li>
287 <li><a href="#int_atomic_load_min"><tt>llvm.atomic.load.min</tt></a></li>
288 <li><a href="#int_atomic_load_umax"><tt>llvm.atomic.load.umax</tt></a></li>
289 <li><a href="#int_atomic_load_umin"><tt>llvm.atomic.load.umin</tt></a></li>
290 </ol>
291 </li>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]292 <li><a href="#int_memorymarkers">Memory Use Markers</a>
293 <ol>
294 <li><a href="#int_lifetime_start"><tt>llvm.lifetime.start</tt></a></li>
295 <li><a href="#int_lifetime_end"><tt>llvm.lifetime.end</tt></a></li>
296 <li><a href="#int_invariant_start"><tt>llvm.invariant.start</tt></a></li>
297 <li><a href="#int_invariant_end"><tt>llvm.invariant.end</tt></a></li>
298 </ol>
299 </li>
Reid Spencer5b2cb0f2007-07-20 19:59:11 +0000[diff] [blame]300 <li><a href="#int_general">General intrinsics</a>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]301 <ol>
Reid Spencer5b2cb0f2007-07-20 19:59:11 +0000[diff] [blame]302 <li><a href="#int_var_annotation">
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]303 '<tt>llvm.var.annotation</tt>' Intrinsic</a></li>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]304 <li><a href="#int_annotation">
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]305 '<tt>llvm.annotation.*</tt>' Intrinsic</a></li>
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]306 <li><a href="#int_trap">
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]307 '<tt>llvm.trap</tt>' Intrinsic</a></li>
308 <li><a href="#int_stackprotector">
309 '<tt>llvm.stackprotector</tt>' Intrinsic</a></li>
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]310 <li><a href="#int_objectsize">
311 '<tt>llvm.objectsize</tt>' Intrinsic</a></li>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]312 </ol>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]313 </li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]314 </ol>
315 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]316</ol>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]317
318<div class="doc_author">
319 <p>Written by <a href="mailto:sabre@nondot.org">Chris Lattner</a>
320 and <a href="mailto:vadve@cs.uiuc.edu">Vikram Adve</a></p>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]321</div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]322
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]323<!-- *********************************************************************** -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]324<div class="doc_section"> <a name="abstract">Abstract </a></div>
325<!-- *********************************************************************** -->
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]326
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]327<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]328
329<p>This document is a reference manual for the LLVM assembly language. LLVM is
330 a Static Single Assignment (SSA) based representation that provides type
331 safety, low-level operations, flexibility, and the capability of representing
332 'all' high-level languages cleanly. It is the common code representation
333 used throughout all phases of the LLVM compilation strategy.</p>
334
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]335</div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]336
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]337<!-- *********************************************************************** -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]338<div class="doc_section"> <a name="introduction">Introduction</a> </div>
339<!-- *********************************************************************** -->
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]340
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]341<div class="doc_text">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]342
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]343<p>The LLVM code representation is designed to be used in three different forms:
344 as an in-memory compiler IR, as an on-disk bitcode representation (suitable
345 for fast loading by a Just-In-Time compiler), and as a human readable
346 assembly language representation. This allows LLVM to provide a powerful
347 intermediate representation for efficient compiler transformations and
348 analysis, while providing a natural means to debug and visualize the
349 transformations. The three different forms of LLVM are all equivalent. This
350 document describes the human readable representation and notation.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]351
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]352<p>The LLVM representation aims to be light-weight and low-level while being
353 expressive, typed, and extensible at the same time. It aims to be a
354 "universal IR" of sorts, by being at a low enough level that high-level ideas
355 may be cleanly mapped to it (similar to how microprocessors are "universal
356 IR's", allowing many source languages to be mapped to them). By providing
357 type information, LLVM can be used as the target of optimizations: for
358 example, through pointer analysis, it can be proven that a C automatic
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]359 variable is never accessed outside of the current function, allowing it to
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]360 be promoted to a simple SSA value instead of a memory location.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]361
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]362</div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]363
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]364<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]365<div class="doc_subsubsection"> <a name="wellformed">Well-Formedness</a> </div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]366
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]367<div class="doc_text">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]368
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]369<p>It is important to note that this document describes 'well formed' LLVM
370 assembly language. There is a difference between what the parser accepts and
371 what is considered 'well formed'. For example, the following instruction is
372 syntactically okay, but not well formed:</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]373
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]374<pre class="doc_code">
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]375%x = <a href="#i_add">add</a> i32 1, %x
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]376</pre>
377
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]378<p>because the definition of <tt>%x</tt> does not dominate all of its uses. The
379 LLVM infrastructure provides a verification pass that may be used to verify
380 that an LLVM module is well formed. This pass is automatically run by the
381 parser after parsing input assembly and by the optimizer before it outputs
382 bitcode. The violations pointed out by the verifier pass indicate bugs in
383 transformation passes or input to the parser.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]384
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]385</div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]386
Chris Lattner87a3dbe2007-10-03 17:34:29 +0000[diff] [blame]387<!-- Describe the typesetting conventions here. -->
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]388
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]389<!-- *********************************************************************** -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]390<div class="doc_section"> <a name="identifiers">Identifiers</a> </div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]391<!-- *********************************************************************** -->
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]392
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]393<div class="doc_text">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]394
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]395<p>LLVM identifiers come in two basic types: global and local. Global
396 identifiers (functions, global variables) begin with the <tt>'@'</tt>
397 character. Local identifiers (register names, types) begin with
398 the <tt>'%'</tt> character. Additionally, there are three different formats
399 for identifiers, for different purposes:</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]400
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]401<ol>
Reid Spencerb23b65f2007-08-07 14:34:28 +0000[diff] [blame]402 <li>Named values are represented as a string of characters with their prefix.
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]403 For example, <tt>%foo</tt>, <tt>@DivisionByZero</tt>,
404 <tt>%a.really.long.identifier</tt>. The actual regular expression used is
405 '<tt>[%@][a-zA-Z$._][a-zA-Z$._0-9]*</tt>'. Identifiers which require
406 other characters in their names can be surrounded with quotes. Special
407 characters may be escaped using <tt>"\xx"</tt> where <tt>xx</tt> is the
408 ASCII code for the character in hexadecimal. In this way, any character
409 can be used in a name value, even quotes themselves.</li>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]410
Reid Spencerb23b65f2007-08-07 14:34:28 +0000[diff] [blame]411 <li>Unnamed values are represented as an unsigned numeric value with their
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]412 prefix. For example, <tt>%12</tt>, <tt>@2</tt>, <tt>%44</tt>.</li>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]413
Reid Spencer8f08d802004-12-09 18:02:53 +0000[diff] [blame]414 <li>Constants, which are described in a <a href="#constants">section about
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]415 constants</a>, below.</li>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]416</ol>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]417
Reid Spencerb23b65f2007-08-07 14:34:28 +0000[diff] [blame]418<p>LLVM requires that values start with a prefix for two reasons: Compilers
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]419 don't need to worry about name clashes with reserved words, and the set of
420 reserved words may be expanded in the future without penalty. Additionally,
421 unnamed identifiers allow a compiler to quickly come up with a temporary
422 variable without having to avoid symbol table conflicts.</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]423
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]424<p>Reserved words in LLVM are very similar to reserved words in other
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]425 languages. There are keywords for different opcodes
426 ('<tt><a href="#i_add">add</a></tt>',
427 '<tt><a href="#i_bitcast">bitcast</a></tt>',
428 '<tt><a href="#i_ret">ret</a></tt>', etc...), for primitive type names
429 ('<tt><a href="#t_void">void</a></tt>',
430 '<tt><a href="#t_primitive">i32</a></tt>', etc...), and others. These
431 reserved words cannot conflict with variable names, because none of them
432 start with a prefix character (<tt>'%'</tt> or <tt>'@'</tt>).</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]433
434<p>Here is an example of LLVM code to multiply the integer variable
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]435 '<tt>%X</tt>' by 8:</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]436
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]437<p>The easy way:</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]438
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]439<pre class="doc_code">
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]440%result = <a href="#i_mul">mul</a> i32 %X, 8
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]441</pre>
442
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]443<p>After strength reduction:</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]444
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]445<pre class="doc_code">
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]446%result = <a href="#i_shl">shl</a> i32 %X, i8 3
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]447</pre>
448
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]449<p>And the hard way:</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]450
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]451<pre class="doc_code">
Gabor Greifbd0328f2009-10-28 13:05:07 +0000[diff] [blame]452%0 = <a href="#i_add">add</a> i32 %X, %X <i>; yields {i32}:%0</i>
453%1 = <a href="#i_add">add</a> i32 %0, %0 <i>; yields {i32}:%1</i>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]454%result = <a href="#i_add">add</a> i32 %1, %1
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]455</pre>
456
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]457<p>This last way of multiplying <tt>%X</tt> by 8 illustrates several important
458 lexical features of LLVM:</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]459
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]460<ol>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]461 <li>Comments are delimited with a '<tt>;</tt>' and go until the end of
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]462 line.</li>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]463
464 <li>Unnamed temporaries are created when the result of a computation is not
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]465 assigned to a named value.</li>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]466
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]467 <li>Unnamed temporaries are numbered sequentially</li>
468</ol>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]469
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]470<p>It also shows a convention that we follow in this document. When
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]471 demonstrating instructions, we will follow an instruction with a comment that
472 defines the type and name of value produced. Comments are shown in italic
473 text.</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]474
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]475</div>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]476
477<!-- *********************************************************************** -->
478<div class="doc_section"> <a name="highlevel">High Level Structure</a> </div>
479<!-- *********************************************************************** -->
480
481<!-- ======================================================================= -->
482<div class="doc_subsection"> <a name="modulestructure">Module Structure</a>
483</div>
484
485<div class="doc_text">
486
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]487<p>LLVM programs are composed of "Module"s, each of which is a translation unit
488 of the input programs. Each module consists of functions, global variables,
489 and symbol table entries. Modules may be combined together with the LLVM
490 linker, which merges function (and global variable) definitions, resolves
491 forward declarations, and merges symbol table entries. Here is an example of
492 the "hello world" module:</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]493
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]494<pre class="doc_code">
Chris Lattner54a7be72010-08-17 17:13:42 +0000[diff] [blame]495<i>; Declare the string constant as a global constant.</i>&nbsp;
Nick Lewyckyfea7ddc2011-01-29 01:09:53 +0000[diff] [blame]496<a href="#identifiers">@.LC0</a> = <a href="#linkage_internal">internal</a>&nbsp;<a href="#globalvars">constant</a>&nbsp;<a href="#t_array">[13 x i8]</a> c"hello world\0A\00" <i>; [13 x i8]*</i>&nbsp;
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]497
Chris Lattner54a7be72010-08-17 17:13:42 +0000[diff] [blame]498<i>; External declaration of the puts function</i>&nbsp;
499<a href="#functionstructure">declare</a> i32 @puts(i8*) <i>; i32 (i8*)* </i>&nbsp;
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]500
501<i>; Definition of main function</i>
Chris Lattner54a7be72010-08-17 17:13:42 +0000[diff] [blame]502define i32 @main() { <i>; i32()* </i>&nbsp;
503 <i>; Convert [13 x i8]* to i8 *...</i>&nbsp;
504 %cast210 = <a href="#i_getelementptr">getelementptr</a> [13 x i8]* @.LC0, i64 0, i64 0 <i>; i8*</i>&nbsp;
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]505
Chris Lattner54a7be72010-08-17 17:13:42 +0000[diff] [blame]506 <i>; Call puts function to write out the string to stdout.</i>&nbsp;
507 <a href="#i_call">call</a> i32 @puts(i8* %cast210) <i>; i32</i>&nbsp;
508 <a href="#i_ret">ret</a> i32 0&nbsp;
509}
Devang Pateld1a89692010-01-11 19:35:55 +0000[diff] [blame]510
511<i>; Named metadata</i>
512!1 = metadata !{i32 41}
513!foo = !{!1, null}
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]514</pre>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]515
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]516<p>This example is made up of a <a href="#globalvars">global variable</a> named
Devang Pateld1a89692010-01-11 19:35:55 +0000[diff] [blame]517 "<tt>.LC0</tt>", an external declaration of the "<tt>puts</tt>" function,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]518 a <a href="#functionstructure">function definition</a> for
Devang Pateld1a89692010-01-11 19:35:55 +0000[diff] [blame]519 "<tt>main</tt>" and <a href="#namedmetadatastructure">named metadata</a>
520 "<tt>foo"</tt>.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]521
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]522<p>In general, a module is made up of a list of global values, where both
523 functions and global variables are global values. Global values are
524 represented by a pointer to a memory location (in this case, a pointer to an
525 array of char, and a pointer to a function), and have one of the
526 following <a href="#linkage">linkage types</a>.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]527
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]528</div>
529
530<!-- ======================================================================= -->
531<div class="doc_subsection">
532 <a name="linkage">Linkage Types</a>
533</div>
534
535<div class="doc_text">
536
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]537<p>All Global Variables and Functions have one of the following types of
538 linkage:</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]539
540<dl>
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]541 <dt><tt><b><a name="linkage_private">private</a></b></tt></dt>
Bill Wendling03bcd6e2010-07-01 21:55:59 +0000[diff] [blame]542 <dd>Global values with "<tt>private</tt>" linkage are only directly accessible
543 by objects in the current module. In particular, linking code into a
544 module with an private global value may cause the private to be renamed as
545 necessary to avoid collisions. Because the symbol is private to the
546 module, all references can be updated. This doesn't show up in any symbol
547 table in the object file.</dd>
Rafael Espindola6de96a12009-01-15 20:18:42 +0000[diff] [blame]548
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]549 <dt><tt><b><a name="linkage_linker_private">linker_private</a></b></tt></dt>
Bill Wendling03bcd6e2010-07-01 21:55:59 +0000[diff] [blame]550 <dd>Similar to <tt>private</tt>, but the symbol is passed through the
551 assembler and evaluated by the linker. Unlike normal strong symbols, they
552 are removed by the linker from the final linked image (executable or
553 dynamic library).</dd>
554
555 <dt><tt><b><a name="linkage_linker_private_weak">linker_private_weak</a></b></tt></dt>
556 <dd>Similar to "<tt>linker_private</tt>", but the symbol is weak. Note that
557 <tt>linker_private_weak</tt> symbols are subject to coalescing by the
558 linker. The symbols are removed by the linker from the final linked image
559 (executable or dynamic library).</dd>
Bill Wendlinga3c6f6b2009-07-20 01:03:30 +0000[diff] [blame]560
Bill Wendling578ee402010-08-20 22:05:50 +0000[diff] [blame]561 <dt><tt><b><a name="linkage_linker_private_weak_def_auto">linker_private_weak_def_auto</a></b></tt></dt>
562 <dd>Similar to "<tt>linker_private_weak</tt>", but it's known that the address
563 of the object is not taken. For instance, functions that had an inline
564 definition, but the compiler decided not to inline it. Note,
565 unlike <tt>linker_private</tt> and <tt>linker_private_weak</tt>,
566 <tt>linker_private_weak_def_auto</tt> may have only <tt>default</tt>
567 visibility. The symbols are removed by the linker from the final linked
568 image (executable or dynamic library).</dd>
569
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]570 <dt><tt><b><a name="linkage_internal">internal</a></b></tt></dt>
Bill Wendling36321712010-06-29 22:34:52 +0000[diff] [blame]571 <dd>Similar to private, but the value shows as a local symbol
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]572 (<tt>STB_LOCAL</tt> in the case of ELF) in the object file. This
573 corresponds to the notion of the '<tt>static</tt>' keyword in C.</dd>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]574
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]575 <dt><tt><b><a name="linkage_available_externally">available_externally</a></b></tt></dt>
Chris Lattner184f1be2009-04-13 05:44:34 +0000[diff] [blame]576 <dd>Globals with "<tt>available_externally</tt>" linkage are never emitted
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]577 into the object file corresponding to the LLVM module. They exist to
578 allow inlining and other optimizations to take place given knowledge of
579 the definition of the global, which is known to be somewhere outside the
580 module. Globals with <tt>available_externally</tt> linkage are allowed to
581 be discarded at will, and are otherwise the same as <tt>linkonce_odr</tt>.
582 This linkage type is only allowed on definitions, not declarations.</dd>
Chris Lattner184f1be2009-04-13 05:44:34 +0000[diff] [blame]583
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]584 <dt><tt><b><a name="linkage_linkonce">linkonce</a></b></tt></dt>
Chris Lattnere20b4702007-01-14 06:51:48 +0000[diff] [blame]585 <dd>Globals with "<tt>linkonce</tt>" linkage are merged with other globals of
Chris Lattner0de4caa2010-01-09 19:15:14 +0000[diff] [blame]586 the same name when linkage occurs. This can be used to implement
587 some forms of inline functions, templates, or other code which must be
588 generated in each translation unit that uses it, but where the body may
589 be overridden with a more definitive definition later. Unreferenced
590 <tt>linkonce</tt> globals are allowed to be discarded. Note that
591 <tt>linkonce</tt> linkage does not actually allow the optimizer to
592 inline the body of this function into callers because it doesn't know if
593 this definition of the function is the definitive definition within the
594 program or whether it will be overridden by a stronger definition.
595 To enable inlining and other optimizations, use "<tt>linkonce_odr</tt>"
596 linkage.</dd>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]597
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]598 <dt><tt><b><a name="linkage_weak">weak</a></b></tt></dt>
Chris Lattnerd0554882009-08-05 05:21:07 +0000[diff] [blame]599 <dd>"<tt>weak</tt>" linkage has the same merging semantics as
600 <tt>linkonce</tt> linkage, except that unreferenced globals with
601 <tt>weak</tt> linkage may not be discarded. This is used for globals that
602 are declared "weak" in C source code.</dd>
603
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]604 <dt><tt><b><a name="linkage_common">common</a></b></tt></dt>
Chris Lattnerd0554882009-08-05 05:21:07 +0000[diff] [blame]605 <dd>"<tt>common</tt>" linkage is most similar to "<tt>weak</tt>" linkage, but
606 they are used for tentative definitions in C, such as "<tt>int X;</tt>" at
607 global scope.
608 Symbols with "<tt>common</tt>" linkage are merged in the same way as
609 <tt>weak symbols</tt>, and they may not be deleted if unreferenced.
Chris Lattner0aff0b22009-08-05 05:41:44 +0000[diff] [blame]610 <tt>common</tt> symbols may not have an explicit section,
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]611 must have a zero initializer, and may not be marked '<a
Chris Lattner0aff0b22009-08-05 05:41:44 +0000[diff] [blame]612 href="#globalvars"><tt>constant</tt></a>'. Functions and aliases may not
613 have common linkage.</dd>
Chris Lattnerd0554882009-08-05 05:21:07 +0000[diff] [blame]614
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]615
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]616 <dt><tt><b><a name="linkage_appending">appending</a></b></tt></dt>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]617 <dd>"<tt>appending</tt>" linkage may only be applied to global variables of
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]618 pointer to array type. When two global variables with appending linkage
619 are linked together, the two global arrays are appended together. This is
620 the LLVM, typesafe, equivalent of having the system linker append together
621 "sections" with identical names when .o files are linked.</dd>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]622
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]623 <dt><tt><b><a name="linkage_externweak">extern_weak</a></b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]624 <dd>The semantics of this linkage follow the ELF object file model: the symbol
625 is weak until linked, if not linked, the symbol becomes null instead of
626 being an undefined reference.</dd>
Anton Korobeynikova0554d92007-01-12 19:20:47 +0000[diff] [blame]627
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]628 <dt><tt><b><a name="linkage_linkonce_odr">linkonce_odr</a></b></tt></dt>
629 <dt><tt><b><a name="linkage_weak_odr">weak_odr</a></b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]630 <dd>Some languages allow differing globals to be merged, such as two functions
631 with different semantics. Other languages, such as <tt>C++</tt>, ensure
Bill Wendling03bcd6e2010-07-01 21:55:59 +0000[diff] [blame]632 that only equivalent globals are ever merged (the "one definition rule"
633 &mdash; "ODR"). Such languages can use the <tt>linkonce_odr</tt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]634 and <tt>weak_odr</tt> linkage types to indicate that the global will only
635 be merged with equivalent globals. These linkage types are otherwise the
636 same as their non-<tt>odr</tt> versions.</dd>
Duncan Sands12da8ce2009-03-07 15:45:40 +0000[diff] [blame]637
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]638 <dt><tt><b><a name="linkage_external">externally visible</a></b></tt>:</dt>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]639 <dd>If none of the above identifiers are used, the global is externally
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]640 visible, meaning that it participates in linkage and can be used to
641 resolve external symbol references.</dd>
Reid Spencer7972c472007-04-11 23:49:50 +0000[diff] [blame]642</dl>
Anton Korobeynikovd61d39e2006-09-14 18:23:27 +0000[diff] [blame]643
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]644<p>The next two types of linkage are targeted for Microsoft Windows platform
645 only. They are designed to support importing (exporting) symbols from (to)
646 DLLs (Dynamic Link Libraries).</p>
Anton Korobeynikovd61d39e2006-09-14 18:23:27 +0000[diff] [blame]647
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]648<dl>
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]649 <dt><tt><b><a name="linkage_dllimport">dllimport</a></b></tt></dt>
Anton Korobeynikovd61d39e2006-09-14 18:23:27 +0000[diff] [blame]650 <dd>"<tt>dllimport</tt>" linkage causes the compiler to reference a function
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]651 or variable via a global pointer to a pointer that is set up by the DLL
652 exporting the symbol. On Microsoft Windows targets, the pointer name is
653 formed by combining <code>__imp_</code> and the function or variable
654 name.</dd>
Anton Korobeynikovd61d39e2006-09-14 18:23:27 +0000[diff] [blame]655
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]656 <dt><tt><b><a name="linkage_dllexport">dllexport</a></b></tt></dt>
Anton Korobeynikovd61d39e2006-09-14 18:23:27 +0000[diff] [blame]657 <dd>"<tt>dllexport</tt>" linkage causes the compiler to provide a global
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]658 pointer to a pointer in a DLL, so that it can be referenced with the
659 <tt>dllimport</tt> attribute. On Microsoft Windows targets, the pointer
660 name is formed by combining <code>__imp_</code> and the function or
661 variable name.</dd>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]662</dl>
663
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]664<p>For example, since the "<tt>.LC0</tt>" variable is defined to be internal, if
665 another module defined a "<tt>.LC0</tt>" variable and was linked with this
666 one, one of the two would be renamed, preventing a collision. Since
667 "<tt>main</tt>" and "<tt>puts</tt>" are external (i.e., lacking any linkage
668 declarations), they are accessible outside of the current module.</p>
669
670<p>It is illegal for a function <i>declaration</i> to have any linkage type
671 other than "externally visible", <tt>dllimport</tt>
672 or <tt>extern_weak</tt>.</p>
673
Duncan Sands12da8ce2009-03-07 15:45:40 +0000[diff] [blame]674<p>Aliases can have only <tt>external</tt>, <tt>internal</tt>, <tt>weak</tt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]675 or <tt>weak_odr</tt> linkages.</p>
676
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]677</div>
678
679<!-- ======================================================================= -->
680<div class="doc_subsection">
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]681 <a name="callingconv">Calling Conventions</a>
682</div>
683
684<div class="doc_text">
685
686<p>LLVM <a href="#functionstructure">functions</a>, <a href="#i_call">calls</a>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]687 and <a href="#i_invoke">invokes</a> can all have an optional calling
688 convention specified for the call. The calling convention of any pair of
689 dynamic caller/callee must match, or the behavior of the program is
690 undefined. The following calling conventions are supported by LLVM, and more
691 may be added in the future:</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]692
693<dl>
694 <dt><b>"<tt>ccc</tt>" - The C calling convention</b>:</dt>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]695 <dd>This calling convention (the default if no other calling convention is
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]696 specified) matches the target C calling conventions. This calling
697 convention supports varargs function calls and tolerates some mismatch in
698 the declared prototype and implemented declaration of the function (as
699 does normal C).</dd>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]700
701 <dt><b>"<tt>fastcc</tt>" - The fast calling convention</b>:</dt>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]702 <dd>This calling convention attempts to make calls as fast as possible
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]703 (e.g. by passing things in registers). This calling convention allows the
704 target to use whatever tricks it wants to produce fast code for the
705 target, without having to conform to an externally specified ABI
Jeffrey Yasskinb8677462010-01-09 19:44:16 +0000[diff] [blame]706 (Application Binary Interface).
707 <a href="CodeGenerator.html#tailcallopt">Tail calls can only be optimized
Chris Lattnera179e4d2010-03-11 00:22:57 +0000[diff] [blame]708 when this or the GHC convention is used.</a> This calling convention
709 does not support varargs and requires the prototype of all callees to
710 exactly match the prototype of the function definition.</dd>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]711
712 <dt><b>"<tt>coldcc</tt>" - The cold calling convention</b>:</dt>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]713 <dd>This calling convention attempts to make code in the caller as efficient
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]714 as possible under the assumption that the call is not commonly executed.
715 As such, these calls often preserve all registers so that the call does
716 not break any live ranges in the caller side. This calling convention
717 does not support varargs and requires the prototype of all callees to
718 exactly match the prototype of the function definition.</dd>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]719
Chris Lattnera179e4d2010-03-11 00:22:57 +0000[diff] [blame]720 <dt><b>"<tt>cc <em>10</em></tt>" - GHC convention</b>:</dt>
721 <dd>This calling convention has been implemented specifically for use by the
722 <a href="http://www.haskell.org/ghc">Glasgow Haskell Compiler (GHC)</a>.
723 It passes everything in registers, going to extremes to achieve this by
724 disabling callee save registers. This calling convention should not be
725 used lightly but only for specific situations such as an alternative to
726 the <em>register pinning</em> performance technique often used when
727 implementing functional programming languages.At the moment only X86
728 supports this convention and it has the following limitations:
729 <ul>
730 <li>On <em>X86-32</em> only supports up to 4 bit type parameters. No
731 floating point types are supported.</li>
732 <li>On <em>X86-64</em> only supports up to 10 bit type parameters and
733 6 floating point parameters.</li>
734 </ul>
735 This calling convention supports
736 <a href="CodeGenerator.html#tailcallopt">tail call optimization</a> but
737 requires both the caller and callee are using it.
738 </dd>
739
Chris Lattner573f64e2005-05-07 01:46:40 +0000[diff] [blame]740 <dt><b>"<tt>cc &lt;<em>n</em>&gt;</tt>" - Numbered convention</b>:</dt>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]741 <dd>Any calling convention may be specified by number, allowing
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]742 target-specific calling conventions to be used. Target specific calling
743 conventions start at 64.</dd>
Chris Lattner573f64e2005-05-07 01:46:40 +0000[diff] [blame]744</dl>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]745
746<p>More calling conventions can be added/defined on an as-needed basis, to
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]747 support Pascal conventions or any other well-known target-independent
748 convention.</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]749
750</div>
751
752<!-- ======================================================================= -->
753<div class="doc_subsection">
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]754 <a name="visibility">Visibility Styles</a>
755</div>
756
757<div class="doc_text">
758
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]759<p>All Global Variables and Functions have one of the following visibility
760 styles:</p>
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]761
762<dl>
763 <dt><b>"<tt>default</tt>" - Default style</b>:</dt>
Chris Lattner67c37d12008-08-05 18:29:16 +0000[diff] [blame]764 <dd>On targets that use the ELF object file format, default visibility means
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]765 that the declaration is visible to other modules and, in shared libraries,
766 means that the declared entity may be overridden. On Darwin, default
767 visibility means that the declaration is visible to other modules. Default
768 visibility corresponds to "external linkage" in the language.</dd>
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]769
770 <dt><b>"<tt>hidden</tt>" - Hidden style</b>:</dt>
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]771 <dd>Two declarations of an object with hidden visibility refer to the same
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]772 object if they are in the same shared object. Usually, hidden visibility
773 indicates that the symbol will not be placed into the dynamic symbol
774 table, so no other module (executable or shared library) can reference it
775 directly.</dd>
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]776
Anton Korobeynikov39f3cff2007-04-29 18:35:00 +0000[diff] [blame]777 <dt><b>"<tt>protected</tt>" - Protected style</b>:</dt>
Anton Korobeynikov39f3cff2007-04-29 18:35:00 +0000[diff] [blame]778 <dd>On ELF, protected visibility indicates that the symbol will be placed in
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]779 the dynamic symbol table, but that references within the defining module
780 will bind to the local symbol. That is, the symbol cannot be overridden by
781 another module.</dd>
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]782</dl>
783
784</div>
785
786<!-- ======================================================================= -->
787<div class="doc_subsection">
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]788 <a name="namedtypes">Named Types</a>
789</div>
790
791<div class="doc_text">
792
793<p>LLVM IR allows you to specify name aliases for certain types. This can make
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]794 it easier to read the IR and make the IR more condensed (particularly when
795 recursive types are involved). An example of a name specification is:</p>
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]796
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]797<pre class="doc_code">
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]798%mytype = type { %mytype*, i32 }
799</pre>
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]800
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]801<p>You may give a name to any <a href="#typesystem">type</a> except
Chris Lattner249b9762010-08-17 23:26:04 +0000[diff] [blame]802 "<a href="#t_void">void</a>". Type name aliases may be used anywhere a type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]803 is expected with the syntax "%mytype".</p>
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]804
805<p>Note that type names are aliases for the structural type that they indicate,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]806 and that you can therefore specify multiple names for the same type. This
807 often leads to confusing behavior when dumping out a .ll file. Since LLVM IR
808 uses structural typing, the name is not part of the type. When printing out
809 LLVM IR, the printer will pick <em>one name</em> to render all types of a
810 particular shape. This means that if you have code where two different
811 source types end up having the same LLVM type, that the dumper will sometimes
812 print the "wrong" or unexpected type. This is an important design point and
813 isn't going to change.</p>
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]814
815</div>
816
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]817<!-- ======================================================================= -->
818<div class="doc_subsection">
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]819 <a name="globalvars">Global Variables</a>
820</div>
821
822<div class="doc_text">
823
Chris Lattner5d5aede2005-02-12 19:30:21 +0000[diff] [blame]824<p>Global variables define regions of memory allocated at compilation time
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]825 instead of run-time. Global variables may optionally be initialized, may
826 have an explicit section to be placed in, and may have an optional explicit
827 alignment specified. A variable may be defined as "thread_local", which
828 means that it will not be shared by threads (each thread will have a
829 separated copy of the variable). A variable may be defined as a global
830 "constant," which indicates that the contents of the variable
831 will <b>never</b> be modified (enabling better optimization, allowing the
832 global data to be placed in the read-only section of an executable, etc).
833 Note that variables that need runtime initialization cannot be marked
834 "constant" as there is a store to the variable.</p>
Chris Lattner5d5aede2005-02-12 19:30:21 +0000[diff] [blame]835
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]836<p>LLVM explicitly allows <em>declarations</em> of global variables to be marked
837 constant, even if the final definition of the global is not. This capability
838 can be used to enable slightly better optimization of the program, but
839 requires the language definition to guarantee that optimizations based on the
840 'constantness' are valid for the translation units that do not include the
841 definition.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]842
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]843<p>As SSA values, global variables define pointer values that are in scope
844 (i.e. they dominate) all basic blocks in the program. Global variables
845 always define a pointer to their "content" type because they describe a
846 region of memory, and all memory objects in LLVM are accessed through
847 pointers.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]848
Rafael Espindola45e6c192011-01-08 16:42:36 +0000[diff] [blame]849<p>Global variables can be marked with <tt>unnamed_addr</tt> which indicates
850 that the address is not significant, only the content. Constants marked
Rafael Espindolaf1ed7812011-01-15 08:20:57 +0000[diff] [blame]851 like this can be merged with other constants if they have the same
852 initializer. Note that a constant with significant address <em>can</em>
853 be merged with a <tt>unnamed_addr</tt> constant, the result being a
854 constant whose address is significant.</p>
Rafael Espindola45e6c192011-01-08 16:42:36 +0000[diff] [blame]855
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]856<p>A global variable may be declared to reside in a target-specific numbered
857 address space. For targets that support them, address spaces may affect how
858 optimizations are performed and/or what target instructions are used to
859 access the variable. The default address space is zero. The address space
860 qualifier must precede any other attributes.</p>
Christopher Lamb308121c2007-12-11 09:31:00 +0000[diff] [blame]861
Chris Lattner662c8722005-11-12 00:45:07 +0000[diff] [blame]862<p>LLVM allows an explicit section to be specified for globals. If the target
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]863 supports it, it will emit globals to the section specified.</p>
Chris Lattner662c8722005-11-12 00:45:07 +0000[diff] [blame]864
Chris Lattner78e00bc2010-04-28 00:13:42 +0000[diff] [blame]865<p>An explicit alignment may be specified for a global, which must be a power
866 of 2. If not present, or if the alignment is set to zero, the alignment of
867 the global is set by the target to whatever it feels convenient. If an
868 explicit alignment is specified, the global is forced to have exactly that
Chris Lattner4bd85e42010-04-28 00:31:12 +0000[diff] [blame]869 alignment. Targets and optimizers are not allowed to over-align the global
870 if the global has an assigned section. In this case, the extra alignment
871 could be observable: for example, code could assume that the globals are
872 densely packed in their section and try to iterate over them as an array,
873 alignment padding would break this iteration.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]874
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]875<p>For example, the following defines a global in a numbered address space with
876 an initializer, section, and alignment:</p>
Chris Lattner5760c502007-01-14 00:27:09 +0000[diff] [blame]877
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]878<pre class="doc_code">
Dan Gohmanaaa679b2009-01-11 00:40:00 +0000[diff] [blame]879@G = addrspace(5) constant float 1.0, section "foo", align 4
Chris Lattner5760c502007-01-14 00:27:09 +0000[diff] [blame]880</pre>
881
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]882</div>
883
884
885<!-- ======================================================================= -->
886<div class="doc_subsection">
887 <a name="functionstructure">Functions</a>
888</div>
889
890<div class="doc_text">
891
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]892<p>LLVM function definitions consist of the "<tt>define</tt>" keyword, an
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]893 optional <a href="#linkage">linkage type</a>, an optional
894 <a href="#visibility">visibility style</a>, an optional
Rafael Espindola45e6c192011-01-08 16:42:36 +0000[diff] [blame]895 <a href="#callingconv">calling convention</a>,
896 an optional <tt>unnamed_addr</tt> attribute, a return type, an optional
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]897 <a href="#paramattrs">parameter attribute</a> for the return type, a function
898 name, a (possibly empty) argument list (each with optional
899 <a href="#paramattrs">parameter attributes</a>), optional
900 <a href="#fnattrs">function attributes</a>, an optional section, an optional
901 alignment, an optional <a href="#gc">garbage collector name</a>, an opening
902 curly brace, a list of basic blocks, and a closing curly brace.</p>
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]903
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]904<p>LLVM function declarations consist of the "<tt>declare</tt>" keyword, an
905 optional <a href="#linkage">linkage type</a>, an optional
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]906 <a href="#visibility">visibility style</a>, an optional
Rafael Espindola45e6c192011-01-08 16:42:36 +0000[diff] [blame]907 <a href="#callingconv">calling convention</a>,
908 an optional <tt>unnamed_addr</tt> attribute, a return type, an optional
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]909 <a href="#paramattrs">parameter attribute</a> for the return type, a function
910 name, a possibly empty list of arguments, an optional alignment, and an
911 optional <a href="#gc">garbage collector name</a>.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]912
Chris Lattner67c37d12008-08-05 18:29:16 +0000[diff] [blame]913<p>A function definition contains a list of basic blocks, forming the CFG
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]914 (Control Flow Graph) for the function. Each basic block may optionally start
915 with a label (giving the basic block a symbol table entry), contains a list
916 of instructions, and ends with a <a href="#terminators">terminator</a>
917 instruction (such as a branch or function return).</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]918
Chris Lattnera59fb102007-06-08 16:52:14 +0000[diff] [blame]919<p>The first basic block in a function is special in two ways: it is immediately
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]920 executed on entrance to the function, and it is not allowed to have
921 predecessor basic blocks (i.e. there can not be any branches to the entry
922 block of a function). Because the block can have no predecessors, it also
923 cannot have any <a href="#i_phi">PHI nodes</a>.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]924
Chris Lattner662c8722005-11-12 00:45:07 +0000[diff] [blame]925<p>LLVM allows an explicit section to be specified for functions. If the target
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]926 supports it, it will emit functions to the section specified.</p>
Chris Lattner662c8722005-11-12 00:45:07 +0000[diff] [blame]927
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]928<p>An explicit alignment may be specified for a function. If not present, or if
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]929 the alignment is set to zero, the alignment of the function is set by the
930 target to whatever it feels convenient. If an explicit alignment is
931 specified, the function is forced to have at least that much alignment. All
932 alignments must be a power of 2.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]933
Rafael Espindola45e6c192011-01-08 16:42:36 +0000[diff] [blame]934<p>If the <tt>unnamed_addr</tt> attribute is given, the address is know to not
935 be significant and two identical functions can be merged</p>.
936
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]937<h5>Syntax:</h5>
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]938<pre class="doc_code">
Chris Lattner0ae02092008-10-13 16:55:18 +0000[diff] [blame]939define [<a href="#linkage">linkage</a>] [<a href="#visibility">visibility</a>]
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]940 [<a href="#callingconv">cconv</a>] [<a href="#paramattrs">ret attrs</a>]
941 &lt;ResultType&gt; @&lt;FunctionName&gt; ([argument list])
942 [<a href="#fnattrs">fn Attrs</a>] [section "name"] [align N]
943 [<a href="#gc">gc</a>] { ... }
944</pre>
Devang Patel02256232008-10-07 17:48:33 +0000[diff] [blame]945
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]946</div>
947
Anton Korobeynikova97b6942007-04-25 14:27:10 +0000[diff] [blame]948<!-- ======================================================================= -->
949<div class="doc_subsection">
950 <a name="aliasstructure">Aliases</a>
951</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]952
Anton Korobeynikova97b6942007-04-25 14:27:10 +0000[diff] [blame]953<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]954
955<p>Aliases act as "second name" for the aliasee value (which can be either
956 function, global variable, another alias or bitcast of global value). Aliases
957 may have an optional <a href="#linkage">linkage type</a>, and an
958 optional <a href="#visibility">visibility style</a>.</p>
Anton Korobeynikova97b6942007-04-25 14:27:10 +0000[diff] [blame]959
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]960<h5>Syntax:</h5>
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]961<pre class="doc_code">
Duncan Sands7e99a942008-09-12 20:48:21 +0000[diff] [blame]962@&lt;Name&gt; = alias [Linkage] [Visibility] &lt;AliaseeTy&gt; @&lt;Aliasee&gt;
Bill Wendling2d8b9a82007-05-29 09:42:13 +0000[diff] [blame]963</pre>
Anton Korobeynikova97b6942007-04-25 14:27:10 +0000[diff] [blame]964
965</div>
966
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]967<!-- ======================================================================= -->
Devang Pateld1a89692010-01-11 19:35:55 +0000[diff] [blame]968<div class="doc_subsection">
969 <a name="namedmetadatastructure">Named Metadata</a>
970</div>
971
972<div class="doc_text">
973
Chris Lattnerc2f8f162010-01-15 21:50:19 +0000[diff] [blame]974<p>Named metadata is a collection of metadata. <a href="#metadata">Metadata
Dan Gohman093cb792010-07-21 18:54:18 +0000[diff] [blame]975 nodes</a> (but not metadata strings) are the only valid operands for
Chris Lattnerc2f8f162010-01-15 21:50:19 +0000[diff] [blame]976 a named metadata.</p>
Devang Pateld1a89692010-01-11 19:35:55 +0000[diff] [blame]977
978<h5>Syntax:</h5>
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]979<pre class="doc_code">
Dan Gohman093cb792010-07-21 18:54:18 +0000[diff] [blame]980; Some unnamed metadata nodes, which are referenced by the named metadata.
981!0 = metadata !{metadata !"zero"}
Devang Pateld1a89692010-01-11 19:35:55 +0000[diff] [blame]982!1 = metadata !{metadata !"one"}
Dan Gohman093cb792010-07-21 18:54:18 +0000[diff] [blame]983!2 = metadata !{metadata !"two"}
Dan Gohman58cd65f2010-07-13 19:48:13 +0000[diff] [blame]984; A named metadata.
Dan Gohman093cb792010-07-21 18:54:18 +0000[diff] [blame]985!name = !{!0, !1, !2}
Devang Pateld1a89692010-01-11 19:35:55 +0000[diff] [blame]986</pre>
Devang Pateld1a89692010-01-11 19:35:55 +0000[diff] [blame]987
988</div>
989
990<!-- ======================================================================= -->
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]991<div class="doc_subsection"><a name="paramattrs">Parameter Attributes</a></div>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]992
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]993<div class="doc_text">
994
995<p>The return type and each parameter of a function type may have a set of
996 <i>parameter attributes</i> associated with them. Parameter attributes are
997 used to communicate additional information about the result or parameters of
998 a function. Parameter attributes are considered to be part of the function,
999 not of the function type, so functions with different parameter attributes
1000 can have the same function type.</p>
1001
1002<p>Parameter attributes are simple keywords that follow the type specified. If
1003 multiple parameter attributes are needed, they are space separated. For
1004 example:</p>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]1005
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]1006<pre class="doc_code">
Nick Lewyckydac78d82009-02-15 23:06:14 +0000[diff] [blame]1007declare i32 @printf(i8* noalias nocapture, ...)
Chris Lattnerd2597d72008-10-04 18:33:34 +0000[diff] [blame]1008declare i32 @atoi(i8 zeroext)
1009declare signext i8 @returns_signed_char()
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]1010</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]1011
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1012<p>Note that any attributes for the function result (<tt>nounwind</tt>,
1013 <tt>readonly</tt>) come immediately after the argument list.</p>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1014
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1015<p>Currently, only the following parameter attributes are defined:</p>
Chris Lattner5cee13f2008-01-11 06:20:47 +0000[diff] [blame]1016
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1017<dl>
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1018 <dt><tt><b>zeroext</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1019 <dd>This indicates to the code generator that the parameter or return value
1020 should be zero-extended to a 32-bit value by the caller (for a parameter)
1021 or the callee (for a return value).</dd>
Chris Lattner5cee13f2008-01-11 06:20:47 +0000[diff] [blame]1022
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1023 <dt><tt><b>signext</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1024 <dd>This indicates to the code generator that the parameter or return value
1025 should be sign-extended to a 32-bit value by the caller (for a parameter)
1026 or the callee (for a return value).</dd>
Chris Lattner5cee13f2008-01-11 06:20:47 +0000[diff] [blame]1027
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1028 <dt><tt><b>inreg</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1029 <dd>This indicates that this parameter or return value should be treated in a
1030 special target-dependent fashion during while emitting code for a function
1031 call or return (usually, by putting it in a register as opposed to memory,
1032 though some targets use it to distinguish between two different kinds of
1033 registers). Use of this attribute is target-specific.</dd>
Chris Lattner5cee13f2008-01-11 06:20:47 +0000[diff] [blame]1034
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1035 <dt><tt><b><a name="byval">byval</a></b></tt></dt>
Chris Lattnerd78dbee2010-11-20 23:49:06 +0000[diff] [blame]1036 <dd><p>This indicates that the pointer parameter should really be passed by
1037 value to the function. The attribute implies that a hidden copy of the
1038 pointee
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1039 is made between the caller and the callee, so the callee is unable to
1040 modify the value in the callee. This attribute is only valid on LLVM
1041 pointer arguments. It is generally used to pass structs and arrays by
1042 value, but is also valid on pointers to scalars. The copy is considered
1043 to belong to the caller not the callee (for example,
1044 <tt><a href="#readonly">readonly</a></tt> functions should not write to
1045 <tt>byval</tt> parameters). This is not a valid attribute for return
Chris Lattnerd78dbee2010-11-20 23:49:06 +0000[diff] [blame]1046 values.</p>
1047
1048 <p>The byval attribute also supports specifying an alignment with
1049 the align attribute. It indicates the alignment of the stack slot to
1050 form and the known alignment of the pointer specified to the call site. If
1051 the alignment is not specified, then the code generator makes a
1052 target-specific assumption.</p></dd>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1053
Dan Gohman3770af52010-07-02 23:18:08 +0000[diff] [blame]1054 <dt><tt><b><a name="sret">sret</a></b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1055 <dd>This indicates that the pointer parameter specifies the address of a
1056 structure that is the return value of the function in the source program.
1057 This pointer must be guaranteed by the caller to be valid: loads and
1058 stores to the structure may be assumed by the callee to not to trap. This
1059 may only be applied to the first parameter. This is not a valid attribute
1060 for return values. </dd>
1061
Dan Gohman3770af52010-07-02 23:18:08 +0000[diff] [blame]1062 <dt><tt><b><a name="noalias">noalias</a></b></tt></dt>
Dan Gohmandf12d082010-07-02 18:41:32 +0000[diff] [blame]1063 <dd>This indicates that pointer values
1064 <a href="#pointeraliasing"><i>based</i></a> on the argument or return
Dan Gohmande256292010-07-02 23:46:54 +0000[diff] [blame]1065 value do not alias pointer values which are not <i>based</i> on it,
1066 ignoring certain "irrelevant" dependencies.
1067 For a call to the parent function, dependencies between memory
1068 references from before or after the call and from those during the call
1069 are "irrelevant" to the <tt>noalias</tt> keyword for the arguments and
1070 return value used in that call.
Dan Gohmandf12d082010-07-02 18:41:32 +0000[diff] [blame]1071 The caller shares the responsibility with the callee for ensuring that
1072 these requirements are met.
1073 For further details, please see the discussion of the NoAlias response in
Dan Gohman6c858db2010-07-06 15:26:33 +0000[diff] [blame]1074 <a href="AliasAnalysis.html#MustMayNo">alias analysis</a>.<br>
1075<br>
John McCall72ed8902010-07-06 21:07:14 +0000[diff] [blame]1076 Note that this definition of <tt>noalias</tt> is intentionally
1077 similar to the definition of <tt>restrict</tt> in C99 for function
Chris Lattner5eff9ca2010-07-06 20:51:35 +0000[diff] [blame]1078 arguments, though it is slightly weaker.
Dan Gohman6c858db2010-07-06 15:26:33 +0000[diff] [blame]1079<br>
1080 For function return values, C99's <tt>restrict</tt> is not meaningful,
1081 while LLVM's <tt>noalias</tt> is.
1082 </dd>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1083
Dan Gohman3770af52010-07-02 23:18:08 +0000[diff] [blame]1084 <dt><tt><b><a name="nocapture">nocapture</a></b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1085 <dd>This indicates that the callee does not make any copies of the pointer
1086 that outlive the callee itself. This is not a valid attribute for return
1087 values.</dd>
1088
Dan Gohman3770af52010-07-02 23:18:08 +0000[diff] [blame]1089 <dt><tt><b><a name="nest">nest</a></b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1090 <dd>This indicates that the pointer parameter can be excised using the
1091 <a href="#int_trampoline">trampoline intrinsics</a>. This is not a valid
1092 attribute for return values.</dd>
1093</dl>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1094
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1095</div>
1096
1097<!-- ======================================================================= -->
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]1098<div class="doc_subsection">
Gordon Henriksen71183b62007-12-10 03:18:06 +0000[diff] [blame]1099 <a name="gc">Garbage Collector Names</a>
1100</div>
1101
1102<div class="doc_text">
Gordon Henriksen71183b62007-12-10 03:18:06 +0000[diff] [blame]1103
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1104<p>Each function may specify a garbage collector name, which is simply a
1105 string:</p>
1106
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]1107<pre class="doc_code">
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1108define void @f() gc "name" { ... }
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1109</pre>
Gordon Henriksen71183b62007-12-10 03:18:06 +0000[diff] [blame]1110
1111<p>The compiler declares the supported values of <i>name</i>. Specifying a
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1112 collector which will cause the compiler to alter its output in order to
1113 support the named garbage collection algorithm.</p>
1114
Gordon Henriksen71183b62007-12-10 03:18:06 +0000[diff] [blame]1115</div>
1116
1117<!-- ======================================================================= -->
1118<div class="doc_subsection">
Devang Patel9eb525d2008-09-26 23:51:19 +0000[diff] [blame]1119 <a name="fnattrs">Function Attributes</a>
Devang Patelcaacdba2008-09-04 23:05:13 +0000[diff] [blame]1120</div>
1121
1122<div class="doc_text">
Devang Patel9eb525d2008-09-26 23:51:19 +0000[diff] [blame]1123
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1124<p>Function attributes are set to communicate additional information about a
1125 function. Function attributes are considered to be part of the function, not
1126 of the function type, so functions with different parameter attributes can
1127 have the same function type.</p>
Devang Patel9eb525d2008-09-26 23:51:19 +0000[diff] [blame]1128
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1129<p>Function attributes are simple keywords that follow the type specified. If
1130 multiple attributes are needed, they are space separated. For example:</p>
Devang Patelcaacdba2008-09-04 23:05:13 +0000[diff] [blame]1131
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]1132<pre class="doc_code">
Devang Patel9eb525d2008-09-26 23:51:19 +0000[diff] [blame]1133define void @f() noinline { ... }
1134define void @f() alwaysinline { ... }
1135define void @f() alwaysinline optsize { ... }
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1136define void @f() optsize { ... }
Bill Wendlingb175fa42008-09-07 10:26:33 +0000[diff] [blame]1137</pre>
Devang Patelcaacdba2008-09-04 23:05:13 +0000[diff] [blame]1138
Bill Wendlingb175fa42008-09-07 10:26:33 +0000[diff] [blame]1139<dl>
Charles Davisbe5557e2010-02-12 00:31:15 +0000[diff] [blame]1140 <dt><tt><b>alignstack(&lt;<em>n</em>&gt;)</b></tt></dt>
1141 <dd>This attribute indicates that, when emitting the prologue and epilogue,
1142 the backend should forcibly align the stack pointer. Specify the
1143 desired alignment, which must be a power of two, in parentheses.
1144
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1145 <dt><tt><b>alwaysinline</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1146 <dd>This attribute indicates that the inliner should attempt to inline this
1147 function into callers whenever possible, ignoring any active inlining size
1148 threshold for this caller.</dd>
Bill Wendlingb175fa42008-09-07 10:26:33 +0000[diff] [blame]1149
Charles Davis22fe1862010-10-25 15:37:09 +0000[diff] [blame]1150 <dt><tt><b>hotpatch</b></tt></dt>
Charles Davis1b2d3722010-10-25 16:29:03 +0000[diff] [blame]1151 <dd>This attribute indicates that the function should be 'hotpatchable',
Charles Davis74205252010-10-25 19:07:39 +0000[diff] [blame]1152 meaning the function can be patched and/or hooked even while it is
1153 loaded into memory. On x86, the function prologue will be preceded
1154 by six bytes of padding and will begin with a two-byte instruction.
1155 Most of the functions in the Windows system DLLs in Windows XP SP2 or
1156 higher were compiled in this fashion.</dd>
Charles Davis22fe1862010-10-25 15:37:09 +0000[diff] [blame]1157
Jakob Stoklund Olesen74bb06c2010-02-06 01:16:28 +0000[diff] [blame]1158 <dt><tt><b>inlinehint</b></tt></dt>
1159 <dd>This attribute indicates that the source code contained a hint that inlining
1160 this function is desirable (such as the "inline" keyword in C/C++). It
1161 is just a hint; it imposes no requirements on the inliner.</dd>
1162
Nick Lewycky14b58da2010-07-06 18:24:09 +0000[diff] [blame]1163 <dt><tt><b>naked</b></tt></dt>
1164 <dd>This attribute disables prologue / epilogue emission for the function.
1165 This can have very system-specific consequences.</dd>
1166
1167 <dt><tt><b>noimplicitfloat</b></tt></dt>
1168 <dd>This attributes disables implicit floating point instructions.</dd>
1169
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1170 <dt><tt><b>noinline</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1171 <dd>This attribute indicates that the inliner should never inline this
1172 function in any situation. This attribute may not be used together with
1173 the <tt>alwaysinline</tt> attribute.</dd>
Devang Patel9eb525d2008-09-26 23:51:19 +0000[diff] [blame]1174
Nick Lewycky14b58da2010-07-06 18:24:09 +0000[diff] [blame]1175 <dt><tt><b>noredzone</b></tt></dt>
1176 <dd>This attribute indicates that the code generator should not use a red
1177 zone, even if the target-specific ABI normally permits it.</dd>
Devang Patel9eb525d2008-09-26 23:51:19 +0000[diff] [blame]1178
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1179 <dt><tt><b>noreturn</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1180 <dd>This function attribute indicates that the function never returns
1181 normally. This produces undefined behavior at runtime if the function
1182 ever does dynamically return.</dd>
Bill Wendlinga8130172008-11-13 01:02:51 +0000[diff] [blame]1183
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1184 <dt><tt><b>nounwind</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1185 <dd>This function attribute indicates that the function never returns with an
1186 unwind or exceptional control flow. If the function does unwind, its
1187 runtime behavior is undefined.</dd>
Bill Wendling0f5541e2008-11-26 19:07:40 +0000[diff] [blame]1188
Nick Lewycky14b58da2010-07-06 18:24:09 +0000[diff] [blame]1189 <dt><tt><b>optsize</b></tt></dt>
1190 <dd>This attribute suggests that optimization passes and code generator passes
1191 make choices that keep the code size of this function low, and otherwise
1192 do optimizations specifically to reduce code size.</dd>
1193
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1194 <dt><tt><b>readnone</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1195 <dd>This attribute indicates that the function computes its result (or decides
1196 to unwind an exception) based strictly on its arguments, without
1197 dereferencing any pointer arguments or otherwise accessing any mutable
1198 state (e.g. memory, control registers, etc) visible to caller functions.
1199 It does not write through any pointer arguments
1200 (including <tt><a href="#byval">byval</a></tt> arguments) and never
1201 changes any state visible to callers. This means that it cannot unwind
1202 exceptions by calling the <tt>C++</tt> exception throwing methods, but
1203 could use the <tt>unwind</tt> instruction.</dd>
Devang Patel310fd4a2009-06-12 19:45:19 +0000[diff] [blame]1204
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1205 <dt><tt><b><a name="readonly">readonly</a></b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1206 <dd>This attribute indicates that the function does not write through any
1207 pointer arguments (including <tt><a href="#byval">byval</a></tt>
1208 arguments) or otherwise modify any state (e.g. memory, control registers,
1209 etc) visible to caller functions. It may dereference pointer arguments
1210 and read state that may be set in the caller. A readonly function always
1211 returns the same value (or unwinds an exception identically) when called
1212 with the same set of arguments and global state. It cannot unwind an
1213 exception by calling the <tt>C++</tt> exception throwing methods, but may
1214 use the <tt>unwind</tt> instruction.</dd>
Anton Korobeynikovc8ce7b082009-07-17 18:07:26 +0000[diff] [blame]1215
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1216 <dt><tt><b><a name="ssp">ssp</a></b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1217 <dd>This attribute indicates that the function should emit a stack smashing
1218 protector. It is in the form of a "canary"&mdash;a random value placed on
1219 the stack before the local variables that's checked upon return from the
1220 function to see if it has been overwritten. A heuristic is used to
1221 determine if a function needs stack protectors or not.<br>
1222<br>
1223 If a function that has an <tt>ssp</tt> attribute is inlined into a
1224 function that doesn't have an <tt>ssp</tt> attribute, then the resulting
1225 function will have an <tt>ssp</tt> attribute.</dd>
1226
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1227 <dt><tt><b>sspreq</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1228 <dd>This attribute indicates that the function should <em>always</em> emit a
1229 stack smashing protector. This overrides
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1230 the <tt><a href="#ssp">ssp</a></tt> function attribute.<br>
1231<br>
1232 If a function that has an <tt>sspreq</tt> attribute is inlined into a
1233 function that doesn't have an <tt>sspreq</tt> attribute or which has
1234 an <tt>ssp</tt> attribute, then the resulting function will have
1235 an <tt>sspreq</tt> attribute.</dd>
Bill Wendlingb175fa42008-09-07 10:26:33 +0000[diff] [blame]1236</dl>
1237
Devang Patelcaacdba2008-09-04 23:05:13 +0000[diff] [blame]1238</div>
1239
1240<!-- ======================================================================= -->
1241<div class="doc_subsection">
Chris Lattner93564892006-04-08 04:40:53 +0000[diff] [blame]1242 <a name="moduleasm">Module-Level Inline Assembly</a>
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]1243</div>
1244
1245<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1246
1247<p>Modules may contain "module-level inline asm" blocks, which corresponds to
1248 the GCC "file scope inline asm" blocks. These blocks are internally
1249 concatenated by LLVM and treated as a single unit, but may be separated in
1250 the <tt>.ll</tt> file if desired. The syntax is very simple:</p>
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]1251
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]1252<pre class="doc_code">
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]1253module asm "inline asm code goes here"
1254module asm "more can go here"
1255</pre>
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]1256
1257<p>The strings can contain any character by escaping non-printable characters.
1258 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]1259 for the number.</p>
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]1260
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1261<p>The inline asm code is simply printed to the machine code .s file when
1262 assembly code is generated.</p>
1263
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]1264</div>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]1265
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1266<!-- ======================================================================= -->
1267<div class="doc_subsection">
1268 <a name="datalayout">Data Layout</a>
1269</div>
1270
1271<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1272
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1273<p>A module may specify a target specific data layout string that specifies how
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1274 data is to be laid out in memory. The syntax for the data layout is
1275 simply:</p>
1276
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]1277<pre class="doc_code">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1278target datalayout = "<i>layout specification</i>"
1279</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1280
1281<p>The <i>layout specification</i> consists of a list of specifications
1282 separated by the minus sign character ('-'). Each specification starts with
1283 a letter and may include other information after the letter to define some
1284 aspect of the data layout. The specifications accepted are as follows:</p>
1285
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1286<dl>
1287 <dt><tt>E</tt></dt>
1288 <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]1289 bits with the most significance have the lowest address location.</dd>
1290
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1291 <dt><tt>e</tt></dt>
Chris Lattner67c37d12008-08-05 18:29:16 +0000[diff] [blame]1292 <dd>Specifies that the target lays out data in little-endian form. That is,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1293 the bits with the least significance have the lowest address
1294 location.</dd>
1295
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1296 <dt><tt>p:<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]1297 <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]1298 <i>preferred</i> alignments. All sizes are in bits. Specifying
1299 the <i>pref</i> alignment is optional. If omitted, the
1300 preceding <tt>:</tt> should be omitted too.</dd>
1301
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1302 <dt><tt>i<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1303 <dd>This specifies the alignment for an integer type of a given bit
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1304 <i>size</i>. The value of <i>size</i> must be in the range [1,2^23).</dd>
1305
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1306 <dt><tt>v<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]1307 <dd>This specifies the alignment for a vector type of a given bit
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1308 <i>size</i>.</dd>
1309
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1310 <dt><tt>f<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]1311 <dd>This specifies the alignment for a floating point type of a given bit
Dale Johannesence522852010-05-28 18:54:47 +0000[diff] [blame]1312 <i>size</i>. Only values of <i>size</i> that are supported by the target
1313 will work. 32 (float) and 64 (double) are supported on all targets;
1314 80 or 128 (different flavors of long double) are also supported on some
1315 targets.
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1316
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1317 <dt><tt>a<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1318 <dd>This specifies the alignment for an aggregate type of a given bit
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1319 <i>size</i>.</dd>
1320
Daniel Dunbar7921a592009-06-08 22:17:53 +0000[diff] [blame]1321 <dt><tt>s<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1322 <dd>This specifies the alignment for a stack object of a given bit
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1323 <i>size</i>.</dd>
Chris Lattnera381eff2009-11-07 09:35:34 +0000[diff] [blame]1324
1325 <dt><tt>n<i>size1</i>:<i>size2</i>:<i>size3</i>...</tt></dt>
1326 <dd>This specifies a set of native integer widths for the target CPU
1327 in bits. For example, it might contain "n32" for 32-bit PowerPC,
1328 "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]1329 this set are considered to support most general arithmetic
Chris Lattnera381eff2009-11-07 09:35:34 +0000[diff] [blame]1330 operations efficiently.</dd>
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1331</dl>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1332
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1333<p>When constructing the data layout for a given target, LLVM starts with a
Dan Gohman61110ae2010-04-28 00:36:01 +0000[diff] [blame]1334 default set of specifications which are then (possibly) overridden by the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1335 specifications in the <tt>datalayout</tt> keyword. The default specifications
1336 are given in this list:</p>
1337
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1338<ul>
1339 <li><tt>E</tt> - big endian</li>
Dan Gohman8ad777d2010-02-23 02:44:03 +0000[diff] [blame]1340 <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]1341 <li><tt>i1:8:8</tt> - i1 is 8-bit (byte) aligned</li>
1342 <li><tt>i8:8:8</tt> - i8 is 8-bit (byte) aligned</li>
1343 <li><tt>i16:16:16</tt> - i16 is 16-bit aligned</li>
1344 <li><tt>i32:32:32</tt> - i32 is 32-bit aligned</li>
Chris Lattner67c37d12008-08-05 18:29:16 +0000[diff] [blame]1345 <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]1346 alignment of 64-bits</li>
1347 <li><tt>f32:32:32</tt> - float is 32-bit aligned</li>
1348 <li><tt>f64:64:64</tt> - double is 64-bit aligned</li>
1349 <li><tt>v64:64:64</tt> - 64-bit vector is 64-bit aligned</li>
1350 <li><tt>v128:128:128</tt> - 128-bit vector is 128-bit aligned</li>
1351 <li><tt>a0:0:1</tt> - aggregates are 8-bit aligned</li>
Daniel Dunbar7921a592009-06-08 22:17:53 +0000[diff] [blame]1352 <li><tt>s0:64:64</tt> - stack objects are 64-bit aligned</li>
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1353</ul>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1354
1355<p>When LLVM is determining the alignment for a given type, it uses the
1356 following rules:</p>
1357
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1358<ol>
1359 <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]1360 specification is used.</li>
1361
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1362 <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]1363 smallest integer type that is larger than the bitwidth of the sought type
1364 is used. If none of the specifications are larger than the bitwidth then
1365 the the largest integer type is used. For example, given the default
1366 specifications above, the i7 type will use the alignment of i8 (next
1367 largest) while both i65 and i256 will use the alignment of i64 (largest
1368 specified).</li>
1369
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1370 <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]1371 largest vector type that is smaller than the sought vector type will be
1372 used as a fall back. This happens because &lt;128 x double&gt; can be
1373 implemented in terms of 64 &lt;2 x double&gt;, for example.</li>
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1374</ol>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1375
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1376</div>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]1377
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1378<!-- ======================================================================= -->
1379<div class="doc_subsection">
1380 <a name="pointeraliasing">Pointer Aliasing Rules</a>
1381</div>
1382
1383<div class="doc_text">
1384
Andreas Bolka8ae4e242009-07-29 00:02:05 +0000[diff] [blame]1385<p>Any memory access must be done through a pointer value associated
Andreas Bolkae39f0332009-07-27 20:37:10 +0000[diff] [blame]1386with an address range of the memory access, otherwise the behavior
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1387is undefined. Pointer values are associated with address ranges
1388according to the following rules:</p>
1389
1390<ul>
Dan Gohmandf12d082010-07-02 18:41:32 +0000[diff] [blame]1391 <li>A pointer value is associated with the addresses associated with
1392 any value it is <i>based</i> on.
Andreas Bolka8ae4e242009-07-29 00:02:05 +0000[diff] [blame]1393 <li>An address of a global variable is associated with the address
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1394 range of the variable's storage.</li>
1395 <li>The result value of an allocation instruction is associated with
1396 the address range of the allocated storage.</li>
1397 <li>A null pointer in the default address-space is associated with
Andreas Bolka8ae4e242009-07-29 00:02:05 +0000[diff] [blame]1398 no address.</li>
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1399 <li>An integer constant other than zero or a pointer value returned
1400 from a function not defined within LLVM may be associated with address
1401 ranges allocated through mechanisms other than those provided by
Andreas Bolka8ae4e242009-07-29 00:02:05 +0000[diff] [blame]1402 LLVM. Such ranges shall not overlap with any ranges of addresses
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1403 allocated by mechanisms provided by LLVM.</li>
Dan Gohmandf12d082010-07-02 18:41:32 +0000[diff] [blame]1404</ul>
1405
1406<p>A pointer value is <i>based</i> on another pointer value according
1407 to the following rules:</p>
1408
1409<ul>
1410 <li>A pointer value formed from a
1411 <tt><a href="#i_getelementptr">getelementptr</a></tt> operation
1412 is <i>based</i> on the first operand of the <tt>getelementptr</tt>.</li>
1413 <li>The result value of a
1414 <tt><a href="#i_bitcast">bitcast</a></tt> is <i>based</i> on the operand
1415 of the <tt>bitcast</tt>.</li>
1416 <li>A pointer value formed by an
1417 <tt><a href="#i_inttoptr">inttoptr</a></tt> is <i>based</i> on all
1418 pointer values that contribute (directly or indirectly) to the
1419 computation of the pointer's value.</li>
1420 <li>The "<i>based</i> on" relationship is transitive.</li>
1421</ul>
1422
1423<p>Note that this definition of <i>"based"</i> is intentionally
1424 similar to the definition of <i>"based"</i> in C99, though it is
1425 slightly weaker.</p>
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1426
1427<p>LLVM IR does not associate types with memory. The result type of a
Andreas Bolka8ae4e242009-07-29 00:02:05 +0000[diff] [blame]1428<tt><a href="#i_load">load</a></tt> merely indicates the size and
1429alignment of the memory from which to load, as well as the
Dan Gohman4eb47192010-06-17 19:23:50 +0000[diff] [blame]1430interpretation of the value. The first operand type of a
Andreas Bolka8ae4e242009-07-29 00:02:05 +0000[diff] [blame]1431<tt><a href="#i_store">store</a></tt> similarly only indicates the size
1432and alignment of the store.</p>
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1433
1434<p>Consequently, type-based alias analysis, aka TBAA, aka
1435<tt>-fstrict-aliasing</tt>, is not applicable to general unadorned
1436LLVM IR. <a href="#metadata">Metadata</a> may be used to encode
1437additional information which specialized optimization passes may use
1438to implement type-based alias analysis.</p>
1439
1440</div>
1441
Jeffrey Yasskin5d284ae2010-04-26 21:21:24 +0000[diff] [blame]1442<!-- ======================================================================= -->
1443<div class="doc_subsection">
1444 <a name="volatile">Volatile Memory Accesses</a>
1445</div>
1446
1447<div class="doc_text">
1448
1449<p>Certain memory accesses, such as <a href="#i_load"><tt>load</tt></a>s, <a
1450href="#i_store"><tt>store</tt></a>s, and <a
1451href="#int_memcpy"><tt>llvm.memcpy</tt></a>s may be marked <tt>volatile</tt>.
1452The optimizers must not change the number of volatile operations or change their
1453order of execution relative to other volatile operations. The optimizers
1454<i>may</i> change the order of volatile operations relative to non-volatile
1455operations. This is not Java's "volatile" and has no cross-thread
1456synchronization behavior.</p>
1457
1458</div>
1459
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1460<!-- *********************************************************************** -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1461<div class="doc_section"> <a name="typesystem">Type System</a> </div>
1462<!-- *********************************************************************** -->
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]1463
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1464<div class="doc_text">
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]1465
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1466<p>The LLVM type system is one of the most important features of the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1467 intermediate representation. Being typed enables a number of optimizations
1468 to be performed on the intermediate representation directly, without having
1469 to do extra analyses on the side before the transformation. A strong type
1470 system makes it easier to read the generated code and enables novel analyses
1471 and transformations that are not feasible to perform on normal three address
1472 code representations.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]1473
1474</div>
1475
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1476<!-- ======================================================================= -->
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1477<div class="doc_subsection"> <a name="t_classifications">Type
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1478Classifications</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1479
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1480<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1481
1482<p>The types fall into a few useful classifications:</p>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]1483
1484<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1485 <tbody>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1486 <tr><th>Classification</th><th>Types</th></tr>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1487 <tr>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1488 <td><a href="#t_integer">integer</a></td>
Reid Spencer138249b2007-05-16 18:44:01 +0000[diff] [blame]1489 <td><tt>i1, i2, i3, ... i8, ... i16, ... i32, ... i64, ... </tt></td>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1490 </tr>
1491 <tr>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1492 <td><a href="#t_floating">floating point</a></td>
1493 <td><tt>float, double, x86_fp80, fp128, ppc_fp128</tt></td>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1494 </tr>
1495 <tr>
1496 <td><a name="t_firstclass">first class</a></td>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1497 <td><a href="#t_integer">integer</a>,
1498 <a href="#t_floating">floating point</a>,
1499 <a href="#t_pointer">pointer</a>,
Dan Gohman08783a882008-06-18 18:42:13 +0000[diff] [blame]1500 <a href="#t_vector">vector</a>,
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]1501 <a href="#t_struct">structure</a>,
1502 <a href="#t_array">array</a>,
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1503 <a href="#t_label">label</a>,
1504 <a href="#t_metadata">metadata</a>.
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1505 </td>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1506 </tr>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1507 <tr>
1508 <td><a href="#t_primitive">primitive</a></td>
1509 <td><a href="#t_label">label</a>,
1510 <a href="#t_void">void</a>,
Tobias Grosser4c8c95b2010-12-28 20:29:31 +0000[diff] [blame]1511 <a href="#t_integer">integer</a>,
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1512 <a href="#t_floating">floating point</a>,
Dale Johannesen33e5c352010-10-01 00:48:59 +0000[diff] [blame]1513 <a href="#t_x86mmx">x86mmx</a>,
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1514 <a href="#t_metadata">metadata</a>.</td>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1515 </tr>
1516 <tr>
1517 <td><a href="#t_derived">derived</a></td>
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]1518 <td><a href="#t_array">array</a>,
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1519 <a href="#t_function">function</a>,
1520 <a href="#t_pointer">pointer</a>,
1521 <a href="#t_struct">structure</a>,
1522 <a href="#t_pstruct">packed structure</a>,
1523 <a href="#t_vector">vector</a>,
1524 <a href="#t_opaque">opaque</a>.
Dan Gohman93bf60d2008-10-14 16:32:04 +0000[diff] [blame]1525 </td>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1526 </tr>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1527 </tbody>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1528</table>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]1529
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1530<p>The <a href="#t_firstclass">first class</a> types are perhaps the most
1531 important. Values of these types are the only ones which can be produced by
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]1532 instructions.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1533
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1534</div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1535
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1536<!-- ======================================================================= -->
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1537<div class="doc_subsection"> <a name="t_primitive">Primitive Types</a> </div>
Chris Lattner43542b32008-01-04 04:34:14 +0000[diff] [blame]1538
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1539<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1540
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1541<p>The primitive types are the fundamental building blocks of the LLVM
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1542 system.</p>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1543
Chris Lattner43542b32008-01-04 04:34:14 +0000[diff] [blame]1544</div>
1545
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1546<!-- _______________________________________________________________________ -->
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]1547<div class="doc_subsubsection"> <a name="t_integer">Integer Type</a> </div>
1548
1549<div class="doc_text">
1550
1551<h5>Overview:</h5>
1552<p>The integer type is a very simple type that simply specifies an arbitrary
1553 bit width for the integer type desired. Any bit width from 1 bit to
1554 2<sup>23</sup>-1 (about 8 million) can be specified.</p>
1555
1556<h5>Syntax:</h5>
1557<pre>
1558 iN
1559</pre>
1560
1561<p>The number of bits the integer will occupy is specified by the <tt>N</tt>
1562 value.</p>
1563
1564<h5>Examples:</h5>
1565<table class="layout">
1566 <tr class="layout">
1567 <td class="left"><tt>i1</tt></td>
1568 <td class="left">a single-bit integer.</td>
1569 </tr>
1570 <tr class="layout">
1571 <td class="left"><tt>i32</tt></td>
1572 <td class="left">a 32-bit integer.</td>
1573 </tr>
1574 <tr class="layout">
1575 <td class="left"><tt>i1942652</tt></td>
1576 <td class="left">a really big integer of over 1 million bits.</td>
1577 </tr>
1578</table>
1579
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]1580</div>
1581
1582<!-- _______________________________________________________________________ -->
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1583<div class="doc_subsubsection"> <a name="t_floating">Floating Point Types</a> </div>
1584
1585<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1586
1587<table>
1588 <tbody>
1589 <tr><th>Type</th><th>Description</th></tr>
1590 <tr><td><tt>float</tt></td><td>32-bit floating point value</td></tr>
1591 <tr><td><tt>double</tt></td><td>64-bit floating point value</td></tr>
1592 <tr><td><tt>fp128</tt></td><td>128-bit floating point value (112-bit mantissa)</td></tr>
1593 <tr><td><tt>x86_fp80</tt></td><td>80-bit floating point value (X87)</td></tr>
1594 <tr><td><tt>ppc_fp128</tt></td><td>128-bit floating point value (two 64-bits)</td></tr>
1595 </tbody>
1596</table>
1597
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1598</div>
1599
1600<!-- _______________________________________________________________________ -->
Dale Johannesen33e5c352010-10-01 00:48:59 +0000[diff] [blame]1601<div class="doc_subsubsection"> <a name="t_x86mmx">X86mmx Type</a> </div>
1602
1603<div class="doc_text">
1604
1605<h5>Overview:</h5>
1606<p>The x86mmx type represents a value held in an MMX register on an x86 machine. The operations allowed on it are quite limited: parameters and return values, load and store, and bitcast. User-specified MMX instructions are represented as intrinsic or asm calls with arguments and/or results of this type. There are no arrays, vectors or constants of this type.</p>
1607
1608<h5>Syntax:</h5>
1609<pre>
Dale Johannesenb1f0ff12010-10-01 01:07:02 +0000[diff] [blame]1610 x86mmx
Dale Johannesen33e5c352010-10-01 00:48:59 +0000[diff] [blame]1611</pre>
1612
1613</div>
1614
1615<!-- _______________________________________________________________________ -->
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1616<div class="doc_subsubsection"> <a name="t_void">Void Type</a> </div>
1617
1618<div class="doc_text">
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1619
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1620<h5>Overview:</h5>
1621<p>The void type does not represent any value and has no size.</p>
1622
1623<h5>Syntax:</h5>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1624<pre>
1625 void
1626</pre>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1627
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1628</div>
1629
1630<!-- _______________________________________________________________________ -->
1631<div class="doc_subsubsection"> <a name="t_label">Label Type</a> </div>
1632
1633<div class="doc_text">
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1634
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1635<h5>Overview:</h5>
1636<p>The label type represents code labels.</p>
1637
1638<h5>Syntax:</h5>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1639<pre>
1640 label
1641</pre>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1642
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1643</div>
1644
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1645<!-- _______________________________________________________________________ -->
1646<div class="doc_subsubsection"> <a name="t_metadata">Metadata Type</a> </div>
1647
1648<div class="doc_text">
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1649
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1650<h5>Overview:</h5>
Nick Lewycky93e06a52009-09-27 23:27:42 +0000[diff] [blame]1651<p>The metadata type represents embedded metadata. No derived types may be
1652 created from metadata except for <a href="#t_function">function</a>
1653 arguments.
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1654
1655<h5>Syntax:</h5>
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1656<pre>
1657 metadata
1658</pre>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1659
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1660</div>
1661
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1662
1663<!-- ======================================================================= -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1664<div class="doc_subsection"> <a name="t_derived">Derived Types</a> </div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1665
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1666<div class="doc_text">
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1667
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1668<p>The real power in LLVM comes from the derived types in the system. This is
1669 what allows a programmer to represent arrays, functions, pointers, and other
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]1670 useful types. Each of these types contain one or more element types which
1671 may be a primitive type, or another derived type. For example, it is
1672 possible to have a two dimensional array, using an array as the element type
1673 of another array.</p>
Dan Gohman142ccc02009-01-24 15:58:40 +0000[diff] [blame]1674
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]1675
1676</div>
1677
1678<!-- _______________________________________________________________________ -->
1679<div class="doc_subsubsection"> <a name="t_aggregate">Aggregate Types</a> </div>
1680
1681<div class="doc_text">
1682
1683<p>Aggregate Types are a subset of derived types that can contain multiple
1684 member types. <a href="#t_array">Arrays</a>,
Chris Lattner13ee7952010-08-28 04:09:24 +0000[diff] [blame]1685 <a href="#t_struct">structs</a>, and <a href="#t_vector">vectors</a> are
1686 aggregate types.</p>
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]1687
1688</div>
1689
Reid Spencer138249b2007-05-16 18:44:01 +0000[diff] [blame]1690<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1691<div class="doc_subsubsection"> <a name="t_array">Array Type</a> </div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1692
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1693<div class="doc_text">
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1694
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1695<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1696<p>The array type is a very simple derived type that arranges elements
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1697 sequentially in memory. The array type requires a size (number of elements)
1698 and an underlying data type.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1699
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]1700<h5>Syntax:</h5>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1701<pre>
1702 [&lt;# elements&gt; x &lt;elementtype&gt;]
1703</pre>
1704
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1705<p>The number of elements is a constant integer value; <tt>elementtype</tt> may
1706 be any type with a size.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1707
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]1708<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1709<table class="layout">
1710 <tr class="layout">
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]1711 <td class="left"><tt>[40 x i32]</tt></td>
1712 <td class="left">Array of 40 32-bit integer values.</td>
1713 </tr>
1714 <tr class="layout">
1715 <td class="left"><tt>[41 x i32]</tt></td>
1716 <td class="left">Array of 41 32-bit integer values.</td>
1717 </tr>
1718 <tr class="layout">
1719 <td class="left"><tt>[4 x i8]</tt></td>
1720 <td class="left">Array of 4 8-bit integer values.</td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1721 </tr>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1722</table>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1723<p>Here are some examples of multidimensional arrays:</p>
1724<table class="layout">
1725 <tr class="layout">
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]1726 <td class="left"><tt>[3 x [4 x i32]]</tt></td>
1727 <td class="left">3x4 array of 32-bit integer values.</td>
1728 </tr>
1729 <tr class="layout">
1730 <td class="left"><tt>[12 x [10 x float]]</tt></td>
1731 <td class="left">12x10 array of single precision floating point values.</td>
1732 </tr>
1733 <tr class="layout">
1734 <td class="left"><tt>[2 x [3 x [4 x i16]]]</tt></td>
1735 <td class="left">2x3x4 array of 16-bit integer values.</td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1736 </tr>
1737</table>
Chris Lattnerc0ad71e2005-06-24 17:22:57 +0000[diff] [blame]1738
Dan Gohmanc74bc282009-11-09 19:01:53 +0000[diff] [blame]1739<p>There is no restriction on indexing beyond the end of the array implied by
1740 a static type (though there are restrictions on indexing beyond the bounds
1741 of an allocated object in some cases). This means that single-dimension
1742 'variable sized array' addressing can be implemented in LLVM with a zero
1743 length array type. An implementation of 'pascal style arrays' in LLVM could
1744 use the type "<tt>{ i32, [0 x float]}</tt>", for example.</p>
Chris Lattnerc0ad71e2005-06-24 17:22:57 +0000[diff] [blame]1745
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1746</div>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1747
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1748<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1749<div class="doc_subsubsection"> <a name="t_function">Function Type</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1750
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1751<div class="doc_text">
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]1752
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1753<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1754<p>The function type can be thought of as a function signature. It consists of
1755 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]1756 function type is a first class type or a void type.</p>
Devang Pateld6cff512008-03-10 20:49:15 +0000[diff] [blame]1757
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1758<h5>Syntax:</h5>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]1759<pre>
Nick Lewycky14d1ccc2009-09-27 07:55:32 +0000[diff] [blame]1760 &lt;returntype&gt; (&lt;parameter list&gt;)
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]1761</pre>
1762
John Criswell4c0cf7f2005-10-24 16:17:18 +0000[diff] [blame]1763<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]1764 specifiers. Optionally, the parameter list may include a type <tt>...</tt>,
1765 which indicates that the function takes a variable number of arguments.
1766 Variable argument functions can access their arguments with
1767 the <a href="#int_varargs">variable argument handling intrinsic</a>
Chris Lattner47f2a832010-03-02 06:36:51 +0000[diff] [blame]1768 functions. '<tt>&lt;returntype&gt;</tt>' is any type except
Nick Lewycky93e06a52009-09-27 23:27:42 +0000[diff] [blame]1769 <a href="#t_label">label</a>.</p>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]1770
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1771<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1772<table class="layout">
1773 <tr class="layout">
Reid Spencer58c08712006-12-31 07:18:34 +0000[diff] [blame]1774 <td class="left"><tt>i32 (i32)</tt></td>
1775 <td class="left">function taking an <tt>i32</tt>, returning an <tt>i32</tt>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1776 </td>
Reid Spencer58c08712006-12-31 07:18:34 +0000[diff] [blame]1777 </tr><tr class="layout">
Chris Lattner47f2a832010-03-02 06:36:51 +0000[diff] [blame]1778 <td class="left"><tt>float&nbsp;(i16,&nbsp;i32&nbsp;*)&nbsp;*
Reid Spencer655dcc62006-12-31 07:20:23 +0000[diff] [blame]1779 </tt></td>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]1780 <td class="left"><a href="#t_pointer">Pointer</a> to a function that takes
Chris Lattner47f2a832010-03-02 06:36:51 +0000[diff] [blame]1781 an <tt>i16</tt> and a <a href="#t_pointer">pointer</a> to <tt>i32</tt>,
1782 returning <tt>float</tt>.
Reid Spencer58c08712006-12-31 07:18:34 +0000[diff] [blame]1783 </td>
1784 </tr><tr class="layout">
1785 <td class="left"><tt>i32 (i8*, ...)</tt></td>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]1786 <td class="left">A vararg function that takes at least one
1787 <a href="#t_pointer">pointer</a> to <tt>i8 </tt> (char in C),
1788 which returns an integer. This is the signature for <tt>printf</tt> in
Reid Spencer58c08712006-12-31 07:18:34 +0000[diff] [blame]1789 LLVM.
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1790 </td>
Devang Patele3dfc1c2008-03-24 05:35:41 +0000[diff] [blame]1791 </tr><tr class="layout">
1792 <td class="left"><tt>{i32, i32} (i32)</tt></td>
Nick Lewycky14d1ccc2009-09-27 07:55:32 +0000[diff] [blame]1793 <td class="left">A function taking an <tt>i32</tt>, returning a
1794 <a href="#t_struct">structure</a> containing two <tt>i32</tt> values
Devang Patele3dfc1c2008-03-24 05:35:41 +0000[diff] [blame]1795 </td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1796 </tr>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1797</table>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]1798
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1799</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1800
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1801<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1802<div class="doc_subsubsection"> <a name="t_struct">Structure Type</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1803
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1804<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1805
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1806<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1807<p>The structure type is used to represent a collection of data members together
1808 in memory. The packing of the field types is defined to match the ABI of the
1809 underlying processor. The elements of a structure may be any type that has a
1810 size.</p>
1811
Jeffrey Yasskinf991bbb2010-01-11 19:19:26 +0000[diff] [blame]1812<p>Structures in memory are accessed using '<tt><a href="#i_load">load</a></tt>'
1813 and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a field
1814 with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.
1815 Structures in registers are accessed using the
1816 '<tt><a href="#i_extractvalue">extractvalue</a></tt>' and
1817 '<tt><a href="#i_insertvalue">insertvalue</a></tt>' instructions.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1818<h5>Syntax:</h5>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1819<pre>
1820 { &lt;type list&gt; }
1821</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1822
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1823<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1824<table class="layout">
1825 <tr class="layout">
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]1826 <td class="left"><tt>{ i32, i32, i32 }</tt></td>
1827 <td class="left">A triple of three <tt>i32</tt> values</td>
1828 </tr><tr class="layout">
1829 <td class="left"><tt>{&nbsp;float,&nbsp;i32&nbsp;(i32)&nbsp;*&nbsp;}</tt></td>
1830 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1831 second element is a <a href="#t_pointer">pointer</a> to a
1832 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1833 an <tt>i32</tt>.</td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1834 </tr>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1835</table>
Dan Gohman142ccc02009-01-24 15:58:40 +0000[diff] [blame]1836
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1837</div>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1838
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1839<!-- _______________________________________________________________________ -->
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]1840<div class="doc_subsubsection"> <a name="t_pstruct">Packed Structure Type</a>
1841</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1842
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]1843<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1844
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]1845<h5>Overview:</h5>
1846<p>The packed structure type is used to represent a collection of data members
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1847 together in memory. There is no padding between fields. Further, the
1848 alignment of a packed structure is 1 byte. The elements of a packed
1849 structure may be any type that has a size.</p>
1850
1851<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt> and
1852 '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a field with
1853 the '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
1854
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]1855<h5>Syntax:</h5>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1856<pre>
1857 &lt; { &lt;type list&gt; } &gt;
1858</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1859
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]1860<h5>Examples:</h5>
1861<table class="layout">
1862 <tr class="layout">
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]1863 <td class="left"><tt>&lt; { i32, i32, i32 } &gt;</tt></td>
1864 <td class="left">A triple of three <tt>i32</tt> values</td>
1865 </tr><tr class="layout">
Bill Wendlingb175fa42008-09-07 10:26:33 +0000[diff] [blame]1866 <td class="left">
1867<tt>&lt;&nbsp;{&nbsp;float,&nbsp;i32&nbsp;(i32)*&nbsp;}&nbsp;&gt;</tt></td>
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]1868 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1869 second element is a <a href="#t_pointer">pointer</a> to a
1870 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1871 an <tt>i32</tt>.</td>
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]1872 </tr>
1873</table>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1874
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]1875</div>
1876
1877<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1878<div class="doc_subsubsection"> <a name="t_pointer">Pointer Type</a> </div>
Chris Lattner4a67c912009-02-08 19:53:29 +0000[diff] [blame]1879
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1880<div class="doc_text">
1881
1882<h5>Overview:</h5>
Dan Gohman88481112010-02-25 16:50:07 +0000[diff] [blame]1883<p>The pointer type is used to specify memory locations.
1884 Pointers are commonly used to reference objects in memory.</p>
1885
1886<p>Pointer types may have an optional address space attribute defining the
1887 numbered address space where the pointed-to object resides. The default
1888 address space is number zero. The semantics of non-zero address
1889 spaces are target-specific.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1890
1891<p>Note that LLVM does not permit pointers to void (<tt>void*</tt>) nor does it
1892 permit pointers to labels (<tt>label*</tt>). Use <tt>i8*</tt> instead.</p>
Chris Lattner4a67c912009-02-08 19:53:29 +0000[diff] [blame]1893
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]1894<h5>Syntax:</h5>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1895<pre>
1896 &lt;type&gt; *
1897</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1898
Chris Lattner590645f2002-04-14 06:13:44 +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">
Dan Gohman623806e2009-01-04 23:44:43 +0000[diff] [blame]1902 <td class="left"><tt>[4 x i32]*</tt></td>
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]1903 <td class="left">A <a href="#t_pointer">pointer</a> to <a
1904 href="#t_array">array</a> of four <tt>i32</tt> values.</td>
1905 </tr>
1906 <tr class="layout">
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]1907 <td class="left"><tt>i32 (i32*) *</tt></td>
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]1908 <td class="left"> A <a href="#t_pointer">pointer</a> to a <a
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1909 href="#t_function">function</a> that takes an <tt>i32*</tt>, returning an
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]1910 <tt>i32</tt>.</td>
1911 </tr>
1912 <tr class="layout">
1913 <td class="left"><tt>i32 addrspace(5)*</tt></td>
1914 <td class="left">A <a href="#t_pointer">pointer</a> to an <tt>i32</tt> value
1915 that resides in address space #5.</td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1916 </tr>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1917</table>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1918
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1919</div>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1920
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1921<!-- _______________________________________________________________________ -->
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]1922<div class="doc_subsubsection"> <a name="t_vector">Vector Type</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1923
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1924<div class="doc_text">
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1925
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1926<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1927<p>A vector type is a simple derived type that represents a vector of elements.
1928 Vector types are used when multiple primitive data are operated in parallel
1929 using a single instruction (SIMD). A vector type requires a size (number of
Duncan Sands31c0e0e2009-11-27 13:38:03 +0000[diff] [blame]1930 elements) and an underlying primitive data type. Vector types are considered
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1931 <a href="#t_firstclass">first class</a>.</p>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1932
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1933<h5>Syntax:</h5>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1934<pre>
1935 &lt; &lt;# elements&gt; x &lt;elementtype&gt; &gt;
1936</pre>
1937
Chris Lattnerf11031a2010-10-10 18:20:35 +0000[diff] [blame]1938<p>The number of elements is a constant integer value larger than 0; elementtype
1939 may be any integer or floating point type. Vectors of size zero are not
1940 allowed, and pointers are not allowed as the element type.</p>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1941
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1942<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1943<table class="layout">
1944 <tr class="layout">
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]1945 <td class="left"><tt>&lt;4 x i32&gt;</tt></td>
1946 <td class="left">Vector of 4 32-bit integer values.</td>
1947 </tr>
1948 <tr class="layout">
1949 <td class="left"><tt>&lt;8 x float&gt;</tt></td>
1950 <td class="left">Vector of 8 32-bit floating-point values.</td>
1951 </tr>
1952 <tr class="layout">
1953 <td class="left"><tt>&lt;2 x i64&gt;</tt></td>
1954 <td class="left">Vector of 2 64-bit integer values.</td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1955 </tr>
1956</table>
Dan Gohman142ccc02009-01-24 15:58:40 +0000[diff] [blame]1957
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1958</div>
1959
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1960<!-- _______________________________________________________________________ -->
1961<div class="doc_subsubsection"> <a name="t_opaque">Opaque Type</a> </div>
1962<div class="doc_text">
1963
1964<h5>Overview:</h5>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1965<p>Opaque types are used to represent unknown types in the system. This
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1966 corresponds (for example) to the C notion of a forward declared structure
1967 type. In LLVM, opaque types can eventually be resolved to any type (not just
1968 a structure type).</p>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1969
1970<h5>Syntax:</h5>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1971<pre>
1972 opaque
1973</pre>
1974
1975<h5>Examples:</h5>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1976<table class="layout">
1977 <tr class="layout">
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]1978 <td class="left"><tt>opaque</tt></td>
1979 <td class="left">An opaque type.</td>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1980 </tr>
1981</table>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1982
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1983</div>
1984
Chris Lattnercf7a5842009-02-02 07:32:36 +0000[diff] [blame]1985<!-- ======================================================================= -->
1986<div class="doc_subsection">
1987 <a name="t_uprefs">Type Up-references</a>
1988</div>
1989
1990<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1991
Chris Lattnercf7a5842009-02-02 07:32:36 +0000[diff] [blame]1992<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1993<p>An "up reference" allows you to refer to a lexically enclosing type without
1994 requiring it to have a name. For instance, a structure declaration may
1995 contain a pointer to any of the types it is lexically a member of. Example
1996 of up references (with their equivalent as named type declarations)
1997 include:</p>
Chris Lattnercf7a5842009-02-02 07:32:36 +0000[diff] [blame]1998
1999<pre>
Chris Lattnerbf1d5452009-02-09 10:00:56 +0000[diff] [blame]2000 { \2 * } %x = type { %x* }
Chris Lattnercf7a5842009-02-02 07:32:36 +0000[diff] [blame]2001 { \2 }* %y = type { %y }*
2002 \1* %z = type %z*
2003</pre>
2004
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2005<p>An up reference is needed by the asmprinter for printing out cyclic types
2006 when there is no declared name for a type in the cycle. Because the
2007 asmprinter does not want to print out an infinite type string, it needs a
2008 syntax to handle recursive types that have no names (all names are optional
2009 in llvm IR).</p>
Chris Lattnercf7a5842009-02-02 07:32:36 +0000[diff] [blame]2010
2011<h5>Syntax:</h5>
2012<pre>
2013 \&lt;level&gt;
2014</pre>
2015
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2016<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]2017
2018<h5>Examples:</h5>
Chris Lattnercf7a5842009-02-02 07:32:36 +0000[diff] [blame]2019<table class="layout">
2020 <tr class="layout">
2021 <td class="left"><tt>\1*</tt></td>
2022 <td class="left">Self-referential pointer.</td>
2023 </tr>
2024 <tr class="layout">
2025 <td class="left"><tt>{ { \3*, i8 }, i32 }</tt></td>
2026 <td class="left">Recursive structure where the upref refers to the out-most
2027 structure.</td>
2028 </tr>
2029</table>
Chris Lattnercf7a5842009-02-02 07:32:36 +0000[diff] [blame]2030
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2031</div>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]2032
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2033<!-- *********************************************************************** -->
2034<div class="doc_section"> <a name="constants">Constants</a> </div>
2035<!-- *********************************************************************** -->
2036
2037<div class="doc_text">
2038
2039<p>LLVM has several different basic types of constants. This section describes
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2040 them all and their syntax.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2041
2042</div>
2043
2044<!-- ======================================================================= -->
Reid Spencer8f08d802004-12-09 18:02:53 +0000[diff] [blame]2045<div class="doc_subsection"><a name="simpleconstants">Simple Constants</a></div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2046
2047<div class="doc_text">
2048
2049<dl>
2050 <dt><b>Boolean constants</b></dt>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2051 <dd>The two strings '<tt>true</tt>' and '<tt>false</tt>' are both valid
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]2052 constants of the <tt><a href="#t_integer">i1</a></tt> type.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2053
2054 <dt><b>Integer constants</b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2055 <dd>Standard integers (such as '4') are constants of
2056 the <a href="#t_integer">integer</a> type. Negative numbers may be used
2057 with integer types.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2058
2059 <dt><b>Floating point constants</b></dt>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2060 <dd>Floating point constants use standard decimal notation (e.g. 123.421),
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2061 exponential notation (e.g. 1.23421e+2), or a more precise hexadecimal
2062 notation (see below). The assembler requires the exact decimal value of a
2063 floating-point constant. For example, the assembler accepts 1.25 but
2064 rejects 1.3 because 1.3 is a repeating decimal in binary. Floating point
2065 constants must have a <a href="#t_floating">floating point</a> type. </dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2066
2067 <dt><b>Null pointer constants</b></dt>
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]2068 <dd>The identifier '<tt>null</tt>' is recognized as a null pointer constant
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2069 and must be of <a href="#t_pointer">pointer type</a>.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2070</dl>
2071
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2072<p>The one non-intuitive notation for constants is the hexadecimal form of
2073 floating point constants. For example, the form '<tt>double
2074 0x432ff973cafa8000</tt>' is equivalent to (but harder to read than)
2075 '<tt>double 4.5e+15</tt>'. The only time hexadecimal floating point
2076 constants are required (and the only time that they are generated by the
2077 disassembler) is when a floating point constant must be emitted but it cannot
2078 be represented as a decimal floating point number in a reasonable number of
2079 digits. For example, NaN's, infinities, and other special values are
2080 represented in their IEEE hexadecimal format so that assembly and disassembly
2081 do not cause any bits to change in the constants.</p>
2082
Dale Johannesencd4a3012009-02-11 22:14:51 +0000[diff] [blame]2083<p>When using the hexadecimal form, constants of types float and double are
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2084 represented using the 16-digit form shown above (which matches the IEEE754
2085 representation for double); float values must, however, be exactly
2086 representable as IEE754 single precision. Hexadecimal format is always used
2087 for long double, and there are three forms of long double. The 80-bit format
2088 used by x86 is represented as <tt>0xK</tt> followed by 20 hexadecimal digits.
2089 The 128-bit format used by PowerPC (two adjacent doubles) is represented
2090 by <tt>0xM</tt> followed by 32 hexadecimal digits. The IEEE 128-bit format
2091 is represented by <tt>0xL</tt> followed by 32 hexadecimal digits; no
2092 currently supported target uses this format. Long doubles will only work if
2093 they match the long double format on your target. All hexadecimal formats
2094 are big-endian (sign bit at the left).</p>
2095
Dale Johannesen33e5c352010-10-01 00:48:59 +0000[diff] [blame]2096<p>There are no constants of type x86mmx.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2097</div>
2098
2099<!-- ======================================================================= -->
Chris Lattner361bfcd2009-02-28 18:32:25 +0000[diff] [blame]2100<div class="doc_subsection">
Bill Wendling972b7202009-07-20 02:32:41 +0000[diff] [blame]2101<a name="aggregateconstants"></a> <!-- old anchor -->
2102<a name="complexconstants">Complex Constants</a>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2103</div>
2104
2105<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2106
Chris Lattner361bfcd2009-02-28 18:32:25 +0000[diff] [blame]2107<p>Complex constants are a (potentially recursive) combination of simple
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2108 constants and smaller complex constants.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2109
2110<dl>
2111 <dt><b>Structure constants</b></dt>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2112 <dd>Structure constants are represented with notation similar to structure
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2113 type definitions (a comma separated list of elements, surrounded by braces
2114 (<tt>{}</tt>)). For example: "<tt>{ i32 4, float 17.0, i32* @G }</tt>",
2115 where "<tt>@G</tt>" is declared as "<tt>@G = external global i32</tt>".
2116 Structure constants must have <a href="#t_struct">structure type</a>, and
2117 the number and types of elements must match those specified by the
2118 type.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2119
2120 <dt><b>Array constants</b></dt>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2121 <dd>Array constants are represented with notation similar to array type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2122 definitions (a comma separated list of elements, surrounded by square
2123 brackets (<tt>[]</tt>)). For example: "<tt>[ i32 42, i32 11, i32 74
2124 ]</tt>". Array constants must have <a href="#t_array">array type</a>, and
2125 the number and types of elements must match those specified by the
2126 type.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2127
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]2128 <dt><b>Vector constants</b></dt>
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]2129 <dd>Vector constants are represented with notation similar to vector type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2130 definitions (a comma separated list of elements, surrounded by
2131 less-than/greater-than's (<tt>&lt;&gt;</tt>)). For example: "<tt>&lt; i32
2132 42, i32 11, i32 74, i32 100 &gt;</tt>". Vector constants must
2133 have <a href="#t_vector">vector type</a>, and the number and types of
2134 elements must match those specified by the type.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2135
2136 <dt><b>Zero initialization</b></dt>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2137 <dd>The string '<tt>zeroinitializer</tt>' can be used to zero initialize a
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]2138 value to zero of <em>any</em> type, including scalar and
2139 <a href="#t_aggregate">aggregate</a> types.
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2140 This is often used to avoid having to print large zero initializers
2141 (e.g. for large arrays) and is always exactly equivalent to using explicit
2142 zero initializers.</dd>
Nick Lewycky49f89192009-04-04 07:22:01 +0000[diff] [blame]2143
2144 <dt><b>Metadata node</b></dt>
Nick Lewycky8e2c4f42009-05-30 16:08:30 +0000[diff] [blame]2145 <dd>A metadata node is a structure-like constant with
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2146 <a href="#t_metadata">metadata type</a>. For example: "<tt>metadata !{
2147 i32 0, metadata !"test" }</tt>". Unlike other constants that are meant to
2148 be interpreted as part of the instruction stream, metadata is a place to
2149 attach additional information such as debug info.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2150</dl>
2151
2152</div>
2153
2154<!-- ======================================================================= -->
2155<div class="doc_subsection">
2156 <a name="globalconstants">Global Variable and Function Addresses</a>
2157</div>
2158
2159<div class="doc_text">
2160
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2161<p>The addresses of <a href="#globalvars">global variables</a>
2162 and <a href="#functionstructure">functions</a> are always implicitly valid
2163 (link-time) constants. These constants are explicitly referenced when
2164 the <a href="#identifiers">identifier for the global</a> is used and always
2165 have <a href="#t_pointer">pointer</a> type. For example, the following is a
2166 legal LLVM file:</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2167
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2168<pre class="doc_code">
Chris Lattner00538a12007-06-06 18:28:13 +0000[diff] [blame]2169@X = global i32 17
2170@Y = global i32 42
2171@Z = global [2 x i32*] [ i32* @X, i32* @Y ]
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2172</pre>
2173
2174</div>
2175
2176<!-- ======================================================================= -->
Reid Spencer641f5c92004-12-09 18:13:12 +0000[diff] [blame]2177<div class="doc_subsection"><a name="undefvalues">Undefined Values</a></div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2178<div class="doc_text">
2179
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2180<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]2181 indicates that the user of the value may receive an unspecified bit-pattern.
Bill Wendling6bbe0912010-10-27 01:07:41 +0000[diff] [blame]2182 Undefined values may be of any type (other than '<tt>label</tt>'
2183 or '<tt>void</tt>') and be used anywhere a constant is permitted.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2184
Chris Lattner92ada5d2009-09-11 01:49:31 +0000[diff] [blame]2185<p>Undefined values are useful because they indicate to the compiler that the
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2186 program is well defined no matter what value is used. This gives the
2187 compiler more freedom to optimize. Here are some examples of (potentially
2188 surprising) transformations that are valid (in pseudo IR):</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2189
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2190
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2191<pre class="doc_code">
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2192 %A = add %X, undef
2193 %B = sub %X, undef
2194 %C = xor %X, undef
2195Safe:
2196 %A = undef
2197 %B = undef
2198 %C = undef
2199</pre>
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2200
2201<p>This is safe because all of the output bits are affected by the undef bits.
Bill Wendling6bbe0912010-10-27 01:07:41 +0000[diff] [blame]2202 Any output bit can have a zero or one depending on the input bits.</p>
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2203
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2204<pre class="doc_code">
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2205 %A = or %X, undef
2206 %B = and %X, undef
2207Safe:
2208 %A = -1
2209 %B = 0
2210Unsafe:
2211 %A = undef
2212 %B = undef
2213</pre>
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2214
2215<p>These logical operations have bits that are not always affected by the input.
Bill Wendling6bbe0912010-10-27 01:07:41 +0000[diff] [blame]2216 For example, if <tt>%X</tt> has a zero bit, then the output of the
2217 '<tt>and</tt>' operation will always be a zero for that bit, no matter what
2218 the corresponding bit from the '<tt>undef</tt>' is. As such, it is unsafe to
2219 optimize or assume that the result of the '<tt>and</tt>' is '<tt>undef</tt>'.
2220 However, it is safe to assume that all bits of the '<tt>undef</tt>' could be
2221 0, and optimize the '<tt>and</tt>' to 0. Likewise, it is safe to assume that
2222 all the bits of the '<tt>undef</tt>' operand to the '<tt>or</tt>' could be
2223 set, allowing the '<tt>or</tt>' to be folded to -1.</p>
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2224
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2225<pre class="doc_code">
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2226 %A = select undef, %X, %Y
2227 %B = select undef, 42, %Y
2228 %C = select %X, %Y, undef
2229Safe:
2230 %A = %X (or %Y)
2231 %B = 42 (or %Y)
2232 %C = %Y
2233Unsafe:
2234 %A = undef
2235 %B = undef
2236 %C = undef
2237</pre>
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2238
Bill Wendling6bbe0912010-10-27 01:07:41 +0000[diff] [blame]2239<p>This set of examples shows that undefined '<tt>select</tt>' (and conditional
2240 branch) conditions can go <em>either way</em>, but they have to come from one
2241 of the two operands. In the <tt>%A</tt> example, if <tt>%X</tt> and
2242 <tt>%Y</tt> were both known to have a clear low bit, then <tt>%A</tt> would
2243 have to have a cleared low bit. However, in the <tt>%C</tt> example, the
2244 optimizer is allowed to assume that the '<tt>undef</tt>' operand could be the
2245 same as <tt>%Y</tt>, allowing the whole '<tt>select</tt>' to be
2246 eliminated.</p>
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2247
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2248<pre class="doc_code">
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2249 %A = xor undef, undef
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]2250
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2251 %B = undef
2252 %C = xor %B, %B
2253
2254 %D = undef
2255 %E = icmp lt %D, 4
2256 %F = icmp gte %D, 4
2257
2258Safe:
2259 %A = undef
2260 %B = undef
2261 %C = undef
2262 %D = undef
2263 %E = undef
2264 %F = undef
2265</pre>
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2266
Bill Wendling6bbe0912010-10-27 01:07:41 +0000[diff] [blame]2267<p>This example points out that two '<tt>undef</tt>' operands are not
2268 necessarily the same. This can be surprising to people (and also matches C
2269 semantics) where they assume that "<tt>X^X</tt>" is always zero, even
2270 if <tt>X</tt> is undefined. This isn't true for a number of reasons, but the
2271 short answer is that an '<tt>undef</tt>' "variable" can arbitrarily change
2272 its value over its "live range". This is true because the variable doesn't
2273 actually <em>have a live range</em>. Instead, the value is logically read
2274 from arbitrary registers that happen to be around when needed, so the value
2275 is not necessarily consistent over time. In fact, <tt>%A</tt> and <tt>%C</tt>
2276 need to have the same semantics or the core LLVM "replace all uses with"
2277 concept would not hold.</p>
Chris Lattnera34a7182009-09-07 23:33:52 +0000[diff] [blame]2278
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2279<pre class="doc_code">
Chris Lattnera34a7182009-09-07 23:33:52 +0000[diff] [blame]2280 %A = fdiv undef, %X
2281 %B = fdiv %X, undef
2282Safe:
2283 %A = undef
2284b: unreachable
2285</pre>
Chris Lattnera34a7182009-09-07 23:33:52 +0000[diff] [blame]2286
2287<p>These examples show the crucial difference between an <em>undefined
Bill Wendling6bbe0912010-10-27 01:07:41 +0000[diff] [blame]2288 value</em> and <em>undefined behavior</em>. An undefined value (like
2289 '<tt>undef</tt>') is allowed to have an arbitrary bit-pattern. This means that
2290 the <tt>%A</tt> operation can be constant folded to '<tt>undef</tt>', because
2291 the '<tt>undef</tt>' could be an SNaN, and <tt>fdiv</tt> is not (currently)
2292 defined on SNaN's. However, in the second example, we can make a more
2293 aggressive assumption: because the <tt>undef</tt> is allowed to be an
2294 arbitrary value, we are allowed to assume that it could be zero. Since a
2295 divide by zero has <em>undefined behavior</em>, we are allowed to assume that
2296 the operation does not execute at all. This allows us to delete the divide and
2297 all code after it. Because the undefined operation "can't happen", the
2298 optimizer can assume that it occurs in dead code.</p>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]2299
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2300<pre class="doc_code">
Chris Lattnera34a7182009-09-07 23:33:52 +0000[diff] [blame]2301a: store undef -> %X
2302b: store %X -> undef
2303Safe:
2304a: &lt;deleted&gt;
2305b: unreachable
2306</pre>
Chris Lattnera34a7182009-09-07 23:33:52 +0000[diff] [blame]2307
Bill Wendling6bbe0912010-10-27 01:07:41 +0000[diff] [blame]2308<p>These examples reiterate the <tt>fdiv</tt> example: a store <em>of</em> an
2309 undefined value can be assumed to not have any effect; we can assume that the
2310 value is overwritten with bits that happen to match what was already there.
2311 However, a store <em>to</em> an undefined location could clobber arbitrary
2312 memory, therefore, it has undefined behavior.</p>
Chris Lattnera34a7182009-09-07 23:33:52 +0000[diff] [blame]2313
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2314</div>
2315
2316<!-- ======================================================================= -->
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]2317<div class="doc_subsection"><a name="trapvalues">Trap Values</a></div>
2318<div class="doc_text">
2319
Dan Gohmanb2a709b2010-04-26 20:21:21 +0000[diff] [blame]2320<p>Trap values are similar to <a href="#undefvalues">undef values</a>, however
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]2321 instead of representing an unspecified bit pattern, they represent the
2322 fact that an instruction or constant expression which cannot evoke side
2323 effects has nevertheless detected a condition which results in undefined
Dan Gohmanb2a709b2010-04-26 20:21:21 +0000[diff] [blame]2324 behavior.</p>
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]2325
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2326<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]2327 only exist when produced by operations such as
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2328 <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]2329
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2330<p>Trap value behavior is defined in terms of value <i>dependence</i>:</p>
Dan Gohmanb8b85c12010-04-26 23:36:52 +0000[diff] [blame]2331
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2332<ul>
2333<li>Values other than <a href="#i_phi"><tt>phi</tt></a> nodes depend on
2334 their operands.</li>
2335
2336<li><a href="#i_phi"><tt>Phi</tt></a> nodes depend on the operand corresponding
2337 to their dynamic predecessor basic block.</li>
2338
2339<li>Function arguments depend on the corresponding actual argument values in
2340 the dynamic callers of their functions.</li>
2341
2342<li><a href="#i_call"><tt>Call</tt></a> instructions depend on the
2343 <a href="#i_ret"><tt>ret</tt></a> instructions that dynamically transfer
2344 control back to them.</li>
2345
Dan Gohman7292a752010-05-03 14:55:22 +0000[diff] [blame]2346<li><a href="#i_invoke"><tt>Invoke</tt></a> instructions depend on the
2347 <a href="#i_ret"><tt>ret</tt></a>, <a href="#i_unwind"><tt>unwind</tt></a>,
2348 or exception-throwing call instructions that dynamically transfer control
2349 back to them.</li>
2350
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2351<li>Non-volatile loads and stores depend on the most recent stores to all of the
2352 referenced memory addresses, following the order in the IR
2353 (including loads and stores implied by intrinsics such as
2354 <a href="#int_memcpy"><tt>@llvm.memcpy</tt></a>.)</li>
2355
Dan Gohman3513ea52010-05-03 14:59:34 +0000[diff] [blame]2356<!-- TODO: In the case of multiple threads, this only applies if the store
2357 "happens-before" the load or store. -->
Dan Gohmanb8b85c12010-04-26 23:36:52 +0000[diff] [blame]2358
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2359<!-- TODO: floating-point exception state -->
Dan Gohmanb8b85c12010-04-26 23:36:52 +0000[diff] [blame]2360
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2361<li>An instruction with externally visible side effects depends on the most
2362 recent preceding instruction with externally visible side effects, following
Dan Gohman6c858db2010-07-06 15:26:33 +0000[diff] [blame]2363 the order in the IR. (This includes
2364 <a href="#volatile">volatile operations</a>.)</li>
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]2365
Dan Gohman7292a752010-05-03 14:55:22 +0000[diff] [blame]2366<li>An instruction <i>control-depends</i> on a
2367 <a href="#terminators">terminator instruction</a>
2368 if the terminator instruction has multiple successors and the instruction
2369 is always executed when control transfers to one of the successors, and
2370 may not be executed when control is transfered to another.</li>
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2371
2372<li>Dependence is transitive.</li>
2373
2374</ul>
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2375
2376<p>Whenever a trap value is generated, all values which depend on it evaluate
2377 to trap. If they have side effects, the evoke their side effects as if each
2378 operand with a trap value were undef. If they have externally-visible side
2379 effects, the behavior is undefined.</p>
2380
2381<p>Here are some examples:</p>
Dan Gohman48a25882010-04-26 20:54:53 +0000[diff] [blame]2382
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2383<pre class="doc_code">
Dan Gohmanb8b85c12010-04-26 23:36:52 +0000[diff] [blame]2384entry:
2385 %trap = sub nuw i32 0, 1 ; Results in a trap value.
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2386 %still_trap = and i32 %trap, 0 ; Whereas (and i32 undef, 0) would return 0.
2387 %trap_yet_again = getelementptr i32* @h, i32 %still_trap
2388 store i32 0, i32* %trap_yet_again ; undefined behavior
2389
2390 store i32 %trap, i32* @g ; Trap value conceptually stored to memory.
2391 %trap2 = load i32* @g ; Returns a trap value, not just undef.
2392
2393 volatile store i32 %trap, i32* @g ; External observation; undefined behavior.
2394
2395 %narrowaddr = bitcast i32* @g to i16*
2396 %wideaddr = bitcast i32* @g to i64*
2397 %trap3 = load 16* %narrowaddr ; Returns a trap value.
2398 %trap4 = load i64* %widaddr ; Returns a trap value.
2399
2400 %cmp = icmp i32 slt %trap, 0 ; Returns a trap value.
Dan Gohmanb8b85c12010-04-26 23:36:52 +0000[diff] [blame]2401 %br i1 %cmp, %true, %end ; Branch to either destination.
2402
2403true:
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2404 volatile store i32 0, i32* @g ; This is control-dependent on %cmp, so
2405 ; it has undefined behavior.
Dan Gohmanb8b85c12010-04-26 23:36:52 +0000[diff] [blame]2406 br label %end
2407
2408end:
2409 %p = phi i32 [ 0, %entry ], [ 1, %true ]
2410 ; Both edges into this PHI are
2411 ; control-dependent on %cmp, so this
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2412 ; always results in a trap value.
Dan Gohmanb8b85c12010-04-26 23:36:52 +0000[diff] [blame]2413
2414 volatile store i32 0, i32* @g ; %end is control-equivalent to %entry
2415 ; so this is defined (ignoring earlier
2416 ; undefined behavior in this example).
Dan Gohmanb8b85c12010-04-26 23:36:52 +0000[diff] [blame]2417</pre>
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]2418
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]2419</div>
2420
2421<!-- ======================================================================= -->
Chris Lattner2bfd3202009-10-27 21:19:13 +0000[diff] [blame]2422<div class="doc_subsection"><a name="blockaddress">Addresses of Basic
2423 Blocks</a></div>
Chris Lattnere4801f72009-10-27 21:01:34 +0000[diff] [blame]2424<div class="doc_text">
2425
Chris Lattneraa99c942009-11-01 01:27:45 +0000[diff] [blame]2426<p><b><tt>blockaddress(@function, %block)</tt></b></p>
Chris Lattnere4801f72009-10-27 21:01:34 +0000[diff] [blame]2427
2428<p>The '<tt>blockaddress</tt>' constant computes the address of the specified
Chris Lattner5c5f0ac2009-10-27 21:49:40 +0000[diff] [blame]2429 basic block in the specified function, and always has an i8* type. Taking
Chris Lattneraa99c942009-11-01 01:27:45 +0000[diff] [blame]2430 the address of the entry block is illegal.</p>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]2431
Chris Lattnere4801f72009-10-27 21:01:34 +0000[diff] [blame]2432<p>This value only has defined behavior when used as an operand to the
Bill Wendling6bbe0912010-10-27 01:07:41 +0000[diff] [blame]2433 '<a href="#i_indirectbr"><tt>indirectbr</tt></a>' instruction, or for
2434 comparisons against null. Pointer equality tests between labels addresses
2435 results in undefined behavior &mdash; though, again, comparison against null
2436 is ok, and no label is equal to the null pointer. This may be passed around
2437 as an opaque pointer sized value as long as the bits are not inspected. This
2438 allows <tt>ptrtoint</tt> and arithmetic to be performed on these values so
2439 long as the original value is reconstituted before the <tt>indirectbr</tt>
2440 instruction.</p>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]2441
Bill Wendling6bbe0912010-10-27 01:07:41 +0000[diff] [blame]2442<p>Finally, some targets may provide defined semantics when using the value as
2443 the operand to an inline assembly, but that is target specific.</p>
Chris Lattnere4801f72009-10-27 21:01:34 +0000[diff] [blame]2444
2445</div>
2446
2447
2448<!-- ======================================================================= -->
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2449<div class="doc_subsection"><a name="constantexprs">Constant Expressions</a>
2450</div>
2451
2452<div class="doc_text">
2453
2454<p>Constant expressions are used to allow expressions involving other constants
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2455 to be used as constants. Constant expressions may be of
2456 any <a href="#t_firstclass">first class</a> type and may involve any LLVM
2457 operation that does not have side effects (e.g. load and call are not
Bill Wendling6bbe0912010-10-27 01:07:41 +0000[diff] [blame]2458 supported). The following is the syntax for constant expressions:</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2459
2460<dl>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2461 <dt><b><tt>trunc (CST to TYPE)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2462 <dd>Truncate a constant to another type. The bit size of CST must be larger
2463 than the bit size of TYPE. Both types must be integers.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2464
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2465 <dt><b><tt>zext (CST to TYPE)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2466 <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]2467 smaller than the bit size of TYPE. Both types must be integers.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2468
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2469 <dt><b><tt>sext (CST to TYPE)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2470 <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]2471 smaller than the bit size of TYPE. Both types must be integers.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2472
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2473 <dt><b><tt>fptrunc (CST to TYPE)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2474 <dd>Truncate a floating point constant to another floating point type. The
2475 size of CST must be larger than the size of TYPE. Both types must be
2476 floating point.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2477
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2478 <dt><b><tt>fpext (CST to TYPE)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2479 <dd>Floating point extend a constant to another type. The size of CST must be
2480 smaller or equal to the size of TYPE. Both types must be floating
2481 point.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2482
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2483 <dt><b><tt>fptoui (CST to TYPE)</tt></b></dt>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2484 <dd>Convert a floating point constant to the corresponding unsigned integer
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2485 constant. TYPE must be a scalar or vector integer type. CST must be of
2486 scalar or vector floating point type. Both CST and TYPE must be scalars,
2487 or vectors of the same number of elements. If the value won't fit in the
2488 integer type, the results are undefined.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2489
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2490 <dt><b><tt>fptosi (CST to TYPE)</tt></b></dt>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2491 <dd>Convert a floating point constant to the corresponding signed integer
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2492 constant. TYPE must be a scalar or vector integer type. CST must be of
2493 scalar or vector floating point type. Both CST and TYPE must be scalars,
2494 or vectors of the same number of elements. If the value won't fit in the
2495 integer type, the results are undefined.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2496
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2497 <dt><b><tt>uitofp (CST to TYPE)</tt></b></dt>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2498 <dd>Convert an unsigned integer constant to the corresponding floating point
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2499 constant. TYPE must be a scalar or vector floating point type. CST must be
2500 of scalar or vector integer type. Both CST and TYPE must be scalars, or
2501 vectors of the same number of elements. If the value won't fit in the
2502 floating point type, the results are undefined.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2503
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2504 <dt><b><tt>sitofp (CST to TYPE)</tt></b></dt>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2505 <dd>Convert a signed integer constant to the corresponding floating point
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2506 constant. TYPE must be a scalar or vector floating point type. CST must be
2507 of scalar or vector integer type. Both CST and TYPE must be scalars, or
2508 vectors of the same number of elements. If the value won't fit in the
2509 floating point type, the results are undefined.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2510
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2511 <dt><b><tt>ptrtoint (CST to TYPE)</tt></b></dt>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]2512 <dd>Convert a pointer typed constant to the corresponding integer constant
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2513 <tt>TYPE</tt> must be an integer type. <tt>CST</tt> must be of pointer
2514 type. The <tt>CST</tt> value is zero extended, truncated, or unchanged to
2515 make it fit in <tt>TYPE</tt>.</dd>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]2516
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2517 <dt><b><tt>inttoptr (CST to TYPE)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2518 <dd>Convert a integer constant to a pointer constant. TYPE must be a pointer
2519 type. CST must be of integer type. The CST value is zero extended,
2520 truncated, or unchanged to make it fit in a pointer size. This one is
2521 <i>really</i> dangerous!</dd>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]2522
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2523 <dt><b><tt>bitcast (CST to TYPE)</tt></b></dt>
Chris Lattner789dee32009-02-28 18:27:03 +0000[diff] [blame]2524 <dd>Convert a constant, CST, to another TYPE. The constraints of the operands
2525 are the same as those for the <a href="#i_bitcast">bitcast
2526 instruction</a>.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2527
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2528 <dt><b><tt>getelementptr (CSTPTR, IDX0, IDX1, ...)</tt></b></dt>
2529 <dt><b><tt>getelementptr inbounds (CSTPTR, IDX0, IDX1, ...)</tt></b></dt>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2530 <dd>Perform the <a href="#i_getelementptr">getelementptr operation</a> on
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2531 constants. As with the <a href="#i_getelementptr">getelementptr</a>
2532 instruction, the index list may have zero or more indexes, which are
2533 required to make sense for the type of "CSTPTR".</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2534
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2535 <dt><b><tt>select (COND, VAL1, VAL2)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2536 <dd>Perform the <a href="#i_select">select operation</a> on constants.</dd>
Reid Spencer9965ee72006-12-04 19:23:19 +0000[diff] [blame]2537
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2538 <dt><b><tt>icmp COND (VAL1, VAL2)</tt></b></dt>
Reid Spencer9965ee72006-12-04 19:23:19 +0000[diff] [blame]2539 <dd>Performs the <a href="#i_icmp">icmp operation</a> on constants.</dd>
2540
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2541 <dt><b><tt>fcmp COND (VAL1, VAL2)</tt></b></dt>
Reid Spencer9965ee72006-12-04 19:23:19 +0000[diff] [blame]2542 <dd>Performs the <a href="#i_fcmp">fcmp operation</a> on constants.</dd>
Robert Bocchino7e97a6d2006-01-10 19:31:34 +0000[diff] [blame]2543
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2544 <dt><b><tt>extractelement (VAL, IDX)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2545 <dd>Perform the <a href="#i_extractelement">extractelement operation</a> on
2546 constants.</dd>
Robert Bocchino7e97a6d2006-01-10 19:31:34 +0000[diff] [blame]2547
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2548 <dt><b><tt>insertelement (VAL, ELT, IDX)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2549 <dd>Perform the <a href="#i_insertelement">insertelement operation</a> on
2550 constants.</dd>
Chris Lattner016a0e52006-04-08 00:13:41 +0000[diff] [blame]2551
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2552 <dt><b><tt>shufflevector (VEC1, VEC2, IDXMASK)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2553 <dd>Perform the <a href="#i_shufflevector">shufflevector operation</a> on
2554 constants.</dd>
Chris Lattner016a0e52006-04-08 00:13:41 +0000[diff] [blame]2555
Nick Lewycky9ab9a7f2010-05-29 06:44:15 +0000[diff] [blame]2556 <dt><b><tt>extractvalue (VAL, IDX0, IDX1, ...)</tt></b></dt>
2557 <dd>Perform the <a href="#i_extractvalue">extractvalue operation</a> on
2558 constants. The index list is interpreted in a similar manner as indices in
2559 a '<a href="#i_getelementptr">getelementptr</a>' operation. At least one
2560 index value must be specified.</dd>
2561
2562 <dt><b><tt>insertvalue (VAL, ELT, IDX0, IDX1, ...)</tt></b></dt>
2563 <dd>Perform the <a href="#i_insertvalue">insertvalue operation</a> on
2564 constants. The index list is interpreted in a similar manner as indices in
2565 a '<a href="#i_getelementptr">getelementptr</a>' operation. At least one
2566 index value must be specified.</dd>
2567
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2568 <dt><b><tt>OPCODE (LHS, RHS)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2569 <dd>Perform the specified operation of the LHS and RHS constants. OPCODE may
2570 be any of the <a href="#binaryops">binary</a>
2571 or <a href="#bitwiseops">bitwise binary</a> operations. The constraints
2572 on operands are the same as those for the corresponding instruction
2573 (e.g. no bitwise operations on floating point values are allowed).</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2574</dl>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2575
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2576</div>
Chris Lattnerb1652612004-03-08 16:49:10 +0000[diff] [blame]2577
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2578<!-- *********************************************************************** -->
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2579<div class="doc_section"> <a name="othervalues">Other Values</a> </div>
2580<!-- *********************************************************************** -->
2581
2582<!-- ======================================================================= -->
2583<div class="doc_subsection">
2584<a name="inlineasm">Inline Assembler Expressions</a>
2585</div>
2586
2587<div class="doc_text">
2588
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2589<p>LLVM supports inline assembler expressions (as opposed
2590 to <a href="#moduleasm"> Module-Level Inline Assembly</a>) through the use of
2591 a special value. This value represents the inline assembler as a string
2592 (containing the instructions to emit), a list of operand constraints (stored
Dale Johannesen63c94fe2009-10-13 21:56:55 +0000[diff] [blame]2593 as a string), a flag that indicates whether or not the inline asm
Dale Johannesen1cfb9582009-10-21 23:28:00 +0000[diff] [blame]2594 expression has side effects, and a flag indicating whether the function
2595 containing the asm needs to align its stack conservatively. An example
2596 inline assembler expression is:</p>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2597
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2598<pre class="doc_code">
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2599i32 (i32) asm "bswap $0", "=r,r"
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2600</pre>
2601
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2602<p>Inline assembler expressions may <b>only</b> be used as the callee operand of
2603 a <a href="#i_call"><tt>call</tt> instruction</a>. Thus, typically we
2604 have:</p>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2605
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2606<pre class="doc_code">
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2607%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]2608</pre>
2609
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2610<p>Inline asms with side effects not visible in the constraint list must be
2611 marked as having side effects. This is done through the use of the
2612 '<tt>sideeffect</tt>' keyword, like so:</p>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2613
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2614<pre class="doc_code">
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2615call void asm sideeffect "eieio", ""()
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2616</pre>
2617
Dale Johannesen1cfb9582009-10-21 23:28:00 +0000[diff] [blame]2618<p>In some cases inline asms will contain code that will not work unless the
2619 stack is aligned in some way, such as calls or SSE instructions on x86,
2620 yet will not contain code that does that alignment within the asm.
2621 The compiler should make conservative assumptions about what the asm might
2622 contain and should generate its usual stack alignment code in the prologue
2623 if the '<tt>alignstack</tt>' keyword is present:</p>
Dale Johannesen63c94fe2009-10-13 21:56:55 +0000[diff] [blame]2624
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2625<pre class="doc_code">
Dale Johannesen1cfb9582009-10-21 23:28:00 +0000[diff] [blame]2626call void asm alignstack "eieio", ""()
Dale Johannesen63c94fe2009-10-13 21:56:55 +0000[diff] [blame]2627</pre>
Dale Johannesen63c94fe2009-10-13 21:56:55 +0000[diff] [blame]2628
2629<p>If both keywords appear the '<tt>sideeffect</tt>' keyword must come
2630 first.</p>
2631
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2632<p>TODO: The format of the asm and constraints string still need to be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2633 documented here. Constraints on what can be done (e.g. duplication, moving,
2634 etc need to be documented). This is probably best done by reference to
2635 another document that covers inline asm from a holistic perspective.</p>
Chris Lattner51065562010-04-07 05:38:05 +0000[diff] [blame]2636</div>
2637
2638<div class="doc_subsubsection">
2639<a name="inlineasm_md">Inline Asm Metadata</a>
2640</div>
2641
2642<div class="doc_text">
2643
2644<p>The call instructions that wrap inline asm nodes may have a "!srcloc" MDNode
Chris Lattner79ffdc72010-11-17 08:20:42 +0000[diff] [blame]2645 attached to it that contains a list of constant integers. If present, the
2646 code generator will use the integer as the location cookie value when report
Chris Lattner51065562010-04-07 05:38:05 +0000[diff] [blame]2647 errors through the LLVMContext error reporting mechanisms. This allows a
Dan Gohman61110ae2010-04-28 00:36:01 +0000[diff] [blame]2648 front-end to correlate backend errors that occur with inline asm back to the
Chris Lattner51065562010-04-07 05:38:05 +0000[diff] [blame]2649 source code that produced it. For example:</p>
2650
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2651<pre class="doc_code">
Chris Lattner51065562010-04-07 05:38:05 +0000[diff] [blame]2652call void asm sideeffect "something bad", ""()<b>, !srcloc !42</b>
2653...
2654!42 = !{ i32 1234567 }
2655</pre>
Chris Lattner51065562010-04-07 05:38:05 +0000[diff] [blame]2656
2657<p>It is up to the front-end to make sense of the magic numbers it places in the
Chris Lattner79ffdc72010-11-17 08:20:42 +0000[diff] [blame]2658 IR. If the MDNode contains multiple constants, the code generator will use
2659 the one that corresponds to the line of the asm that the error occurs on.</p>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2660
2661</div>
2662
Chris Lattnerc2f8f162010-01-15 21:50:19 +0000[diff] [blame]2663<!-- ======================================================================= -->
2664<div class="doc_subsection"><a name="metadata">Metadata Nodes and Metadata
2665 Strings</a>
2666</div>
2667
2668<div class="doc_text">
2669
2670<p>LLVM IR allows metadata to be attached to instructions in the program that
2671 can convey extra information about the code to the optimizers and code
2672 generator. One example application of metadata is source-level debug
2673 information. There are two metadata primitives: strings and nodes. All
2674 metadata has the <tt>metadata</tt> type and is identified in syntax by a
2675 preceding exclamation point ('<tt>!</tt>').</p>
2676
2677<p>A metadata string is a string surrounded by double quotes. It can contain
2678 any character by escaping non-printable characters with "\xx" where "xx" is
2679 the two digit hex code. For example: "<tt>!"test\00"</tt>".</p>
2680
2681<p>Metadata nodes are represented with notation similar to structure constants
2682 (a comma separated list of elements, surrounded by braces and preceded by an
2683 exclamation point). For example: "<tt>!{ metadata !"test\00", i32
2684 10}</tt>". Metadata nodes can have any values as their operand.</p>
2685
2686<p>A <a href="#namedmetadatastructure">named metadata</a> is a collection of
2687 metadata nodes, which can be looked up in the module symbol table. For
2688 example: "<tt>!foo = metadata !{!4, !3}</tt>".
2689
Devang Patel9984bd62010-03-04 23:44:48 +0000[diff] [blame]2690<p>Metadata can be used as function arguments. Here <tt>llvm.dbg.value</tt>
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2691 function is using two metadata arguments.</p>
Devang Patel9984bd62010-03-04 23:44:48 +0000[diff] [blame]2692
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2693 <pre class="doc_code">
Devang Patel9984bd62010-03-04 23:44:48 +0000[diff] [blame]2694 call void @llvm.dbg.value(metadata !24, i64 0, metadata !25)
2695 </pre>
Devang Patel9984bd62010-03-04 23:44:48 +0000[diff] [blame]2696
2697<p>Metadata can be attached with an instruction. Here metadata <tt>!21</tt> is
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2698 attached with <tt>add</tt> instruction using <tt>!dbg</tt> identifier.</p>
Devang Patel9984bd62010-03-04 23:44:48 +0000[diff] [blame]2699
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2700 <pre class="doc_code">
Devang Patel9984bd62010-03-04 23:44:48 +0000[diff] [blame]2701 %indvar.next = add i64 %indvar, 1, !dbg !21
2702 </pre>
Chris Lattnerc2f8f162010-01-15 21:50:19 +0000[diff] [blame]2703</div>
2704
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]2705
2706<!-- *********************************************************************** -->
2707<div class="doc_section">
2708 <a name="intrinsic_globals">Intrinsic Global Variables</a>
2709</div>
2710<!-- *********************************************************************** -->
2711
2712<p>LLVM has a number of "magic" global variables that contain data that affect
2713code generation or other IR semantics. These are documented here. All globals
Chris Lattner58f9bb22009-07-20 06:14:25 +0000[diff] [blame]2714of this sort should have a section specified as "<tt>llvm.metadata</tt>". This
2715section and all globals that start with "<tt>llvm.</tt>" are reserved for use
2716by LLVM.</p>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]2717
2718<!-- ======================================================================= -->
2719<div class="doc_subsection">
2720<a name="intg_used">The '<tt>llvm.used</tt>' Global Variable</a>
2721</div>
2722
2723<div class="doc_text">
2724
2725<p>The <tt>@llvm.used</tt> global is an array with i8* element type which has <a
2726href="#linkage_appending">appending linkage</a>. This array contains a list of
2727pointers to global variables and functions which may optionally have a pointer
2728cast formed of bitcast or getelementptr. For example, a legal use of it is:</p>
2729
2730<pre>
2731 @X = global i8 4
2732 @Y = global i32 123
2733
2734 @llvm.used = appending global [2 x i8*] [
2735 i8* @X,
2736 i8* bitcast (i32* @Y to i8*)
2737 ], section "llvm.metadata"
2738</pre>
2739
2740<p>If a global variable appears in the <tt>@llvm.used</tt> list, then the
2741compiler, assembler, and linker are required to treat the symbol as if there is
2742a reference to the global that it cannot see. For example, if a variable has
2743internal linkage and no references other than that from the <tt>@llvm.used</tt>
2744list, it cannot be deleted. This is commonly used to represent references from
2745inline asms and other things the compiler cannot "see", and corresponds to
2746"attribute((used))" in GNU C.</p>
2747
2748<p>On some targets, the code generator must emit a directive to the assembler or
2749object file to prevent the assembler and linker from molesting the symbol.</p>
2750
2751</div>
2752
2753<!-- ======================================================================= -->
2754<div class="doc_subsection">
Chris Lattner58f9bb22009-07-20 06:14:25 +0000[diff] [blame]2755<a name="intg_compiler_used">The '<tt>llvm.compiler.used</tt>' Global Variable</a>
2756</div>
2757
2758<div class="doc_text">
2759
2760<p>The <tt>@llvm.compiler.used</tt> directive is the same as the
2761<tt>@llvm.used</tt> directive, except that it only prevents the compiler from
2762touching the symbol. On targets that support it, this allows an intelligent
2763linker to optimize references to the symbol without being impeded as it would be
2764by <tt>@llvm.used</tt>.</p>
2765
2766<p>This is a rare construct that should only be used in rare circumstances, and
2767should not be exposed to source languages.</p>
2768
2769</div>
2770
2771<!-- ======================================================================= -->
2772<div class="doc_subsection">
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]2773<a name="intg_global_ctors">The '<tt>llvm.global_ctors</tt>' Global Variable</a>
2774</div>
2775
2776<div class="doc_text">
David Chisnalla9d4a6f2010-04-30 19:23:49 +0000[diff] [blame]2777<pre>
2778%0 = type { i32, void ()* }
David Chisnallb492b812010-04-30 19:27:35 +0000[diff] [blame]2779@llvm.global_ctors = appending global [1 x %0] [%0 { i32 65535, void ()* @ctor }]
David Chisnalla9d4a6f2010-04-30 19:23:49 +0000[diff] [blame]2780</pre>
2781<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.
2782</p>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]2783
2784</div>
2785
2786<!-- ======================================================================= -->
2787<div class="doc_subsection">
2788<a name="intg_global_dtors">The '<tt>llvm.global_dtors</tt>' Global Variable</a>
2789</div>
2790
2791<div class="doc_text">
David Chisnalla9d4a6f2010-04-30 19:23:49 +0000[diff] [blame]2792<pre>
2793%0 = type { i32, void ()* }
David Chisnallb492b812010-04-30 19:27:35 +0000[diff] [blame]2794@llvm.global_dtors = appending global [1 x %0] [%0 { i32 65535, void ()* @dtor }]
David Chisnalla9d4a6f2010-04-30 19:23:49 +0000[diff] [blame]2795</pre>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]2796
David Chisnalla9d4a6f2010-04-30 19:23:49 +0000[diff] [blame]2797<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.
2798</p>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]2799
2800</div>
2801
2802
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2803<!-- *********************************************************************** -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2804<div class="doc_section"> <a name="instref">Instruction Reference</a> </div>
2805<!-- *********************************************************************** -->
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2806
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2807<div class="doc_text">
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2808
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2809<p>The LLVM instruction set consists of several different classifications of
2810 instructions: <a href="#terminators">terminator
2811 instructions</a>, <a href="#binaryops">binary instructions</a>,
2812 <a href="#bitwiseops">bitwise binary instructions</a>,
2813 <a href="#memoryops">memory instructions</a>, and
2814 <a href="#otherops">other instructions</a>.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2815
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2816</div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2817
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2818<!-- ======================================================================= -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2819<div class="doc_subsection"> <a name="terminators">Terminator
2820Instructions</a> </div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2821
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2822<div class="doc_text">
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2823
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2824<p>As mentioned <a href="#functionstructure">previously</a>, every basic block
2825 in a program ends with a "Terminator" instruction, which indicates which
2826 block should be executed after the current block is finished. These
2827 terminator instructions typically yield a '<tt>void</tt>' value: they produce
2828 control flow, not values (the one exception being the
2829 '<a href="#i_invoke"><tt>invoke</tt></a>' instruction).</p>
2830
Duncan Sands626b0242010-04-15 20:35:54 +0000[diff] [blame]2831<p>There are seven different terminator instructions: the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2832 '<a href="#i_ret"><tt>ret</tt></a>' instruction, the
2833 '<a href="#i_br"><tt>br</tt></a>' instruction, the
2834 '<a href="#i_switch"><tt>switch</tt></a>' instruction, the
Bill Wendling33fef7e2009-11-02 00:25:26 +0000[diff] [blame]2835 '<a href="#i_indirectbr">'<tt>indirectbr</tt></a>' Instruction, the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2836 '<a href="#i_invoke"><tt>invoke</tt></a>' instruction, the
2837 '<a href="#i_unwind"><tt>unwind</tt></a>' instruction, and the
2838 '<a href="#i_unreachable"><tt>unreachable</tt></a>' instruction.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2839
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2840</div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2841
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2842<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2843<div class="doc_subsubsection"> <a name="i_ret">'<tt>ret</tt>'
2844Instruction</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2845
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2846<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2847
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2848<h5>Syntax:</h5>
Dan Gohmancc3132e2008-10-04 19:00:07 +0000[diff] [blame]2849<pre>
2850 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]2851 ret void <i>; Return from void function</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2852</pre>
Chris Lattnerda508ac2008-04-23 04:59:35 +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>ret</tt>' instruction is used to return control flow (and optionally
2856 a value) from a function back to the caller.</p>
2857
2858<p>There are two forms of the '<tt>ret</tt>' instruction: one that returns a
2859 value and then causes control flow, and one that just causes control flow to
2860 occur.</p>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]2861
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2862<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2863<p>The '<tt>ret</tt>' instruction optionally accepts a single argument, the
2864 return value. The type of the return value must be a
2865 '<a href="#t_firstclass">first class</a>' type.</p>
Dan Gohmancc3132e2008-10-04 19:00:07 +0000[diff] [blame]2866
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2867<p>A function is not <a href="#wellformed">well formed</a> if it it has a
2868 non-void return type and contains a '<tt>ret</tt>' instruction with no return
2869 value or a return value with a type that does not match its type, or if it
2870 has a void return type and contains a '<tt>ret</tt>' instruction with a
2871 return value.</p>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]2872
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2873<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2874<p>When the '<tt>ret</tt>' instruction is executed, control flow returns back to
2875 the calling function's context. If the caller is a
2876 "<a href="#i_call"><tt>call</tt></a>" instruction, execution continues at the
2877 instruction after the call. If the caller was an
2878 "<a href="#i_invoke"><tt>invoke</tt></a>" instruction, execution continues at
2879 the beginning of the "normal" destination block. If the instruction returns
2880 a value, that value shall set the call or invoke instruction's return
2881 value.</p>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]2882
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2883<h5>Example:</h5>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]2884<pre>
2885 ret i32 5 <i>; Return an integer value of 5</i>
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]2886 ret void <i>; Return from a void function</i>
Bill Wendling050ee8f2009-02-28 22:12:54 +0000[diff] [blame]2887 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]2888</pre>
Dan Gohman3065b612009-01-12 23:12:39 +0000[diff] [blame]2889
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2890</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2891<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2892<div class="doc_subsubsection"> <a name="i_br">'<tt>br</tt>' Instruction</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2893
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2894<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2895
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2896<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2897<pre>
2898 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]2899</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2900
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2901<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2902<p>The '<tt>br</tt>' instruction is used to cause control flow to transfer to a
2903 different basic block in the current function. There are two forms of this
2904 instruction, corresponding to a conditional branch and an unconditional
2905 branch.</p>
2906
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2907<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2908<p>The conditional branch form of the '<tt>br</tt>' instruction takes a single
2909 '<tt>i1</tt>' value and two '<tt>label</tt>' values. The unconditional form
2910 of the '<tt>br</tt>' instruction takes a single '<tt>label</tt>' value as a
2911 target.</p>
2912
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2913<h5>Semantics:</h5>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]2914<p>Upon execution of a conditional '<tt>br</tt>' instruction, the '<tt>i1</tt>'
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2915 argument is evaluated. If the value is <tt>true</tt>, control flows to the
2916 '<tt>iftrue</tt>' <tt>label</tt> argument. If "cond" is <tt>false</tt>,
2917 control flows to the '<tt>iffalse</tt>' <tt>label</tt> argument.</p>
2918
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2919<h5>Example:</h5>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]2920<pre>
2921Test:
2922 %cond = <a href="#i_icmp">icmp</a> eq i32 %a, %b
2923 br i1 %cond, label %IfEqual, label %IfUnequal
2924IfEqual:
2925 <a href="#i_ret">ret</a> i32 1
2926IfUnequal:
2927 <a href="#i_ret">ret</a> i32 0
2928</pre>
2929
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2930</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2931
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2932<!-- _______________________________________________________________________ -->
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2933<div class="doc_subsubsection">
2934 <a name="i_switch">'<tt>switch</tt>' Instruction</a>
2935</div>
2936
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2937<div class="doc_text">
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2938
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2939<h5>Syntax:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2940<pre>
2941 switch &lt;intty&gt; &lt;value&gt;, label &lt;defaultdest&gt; [ &lt;intty&gt; &lt;val&gt;, label &lt;dest&gt; ... ]
2942</pre>
2943
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2944<h5>Overview:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2945<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]2946 several different places. It is a generalization of the '<tt>br</tt>'
2947 instruction, allowing a branch to occur to one of many possible
2948 destinations.</p>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2949
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2950<h5>Arguments:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2951<p>The '<tt>switch</tt>' instruction uses three parameters: an integer
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2952 comparison value '<tt>value</tt>', a default '<tt>label</tt>' destination,
2953 and an array of pairs of comparison value constants and '<tt>label</tt>'s.
2954 The table is not allowed to contain duplicate constant entries.</p>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2955
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2956<h5>Semantics:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2957<p>The <tt>switch</tt> instruction specifies a table of values and
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2958 destinations. When the '<tt>switch</tt>' instruction is executed, this table
2959 is searched for the given value. If the value is found, control flow is
Benjamin Kramer0f420382009-10-12 14:46:08 +0000[diff] [blame]2960 transferred to the corresponding destination; otherwise, control flow is
2961 transferred to the default destination.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2962
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2963<h5>Implementation:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2964<p>Depending on properties of the target machine and the particular
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2965 <tt>switch</tt> instruction, this instruction may be code generated in
2966 different ways. For example, it could be generated as a series of chained
2967 conditional branches or with a lookup table.</p>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2968
2969<h5>Example:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2970<pre>
2971 <i>; Emulate a conditional br instruction</i>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]2972 %Val = <a href="#i_zext">zext</a> i1 %value to i32
Dan Gohman623806e2009-01-04 23:44:43 +0000[diff] [blame]2973 switch i32 %Val, label %truedest [ i32 0, label %falsedest ]
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2974
2975 <i>; Emulate an unconditional br instruction</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2976 switch i32 0, label %dest [ ]
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2977
2978 <i>; Implement a jump table:</i>
Dan Gohman623806e2009-01-04 23:44:43 +0000[diff] [blame]2979 switch i32 %val, label %otherwise [ i32 0, label %onzero
2980 i32 1, label %onone
2981 i32 2, label %ontwo ]
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2982</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2983
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2984</div>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]2985
Chris Lattner3ed871f2009-10-27 19:13:16 +0000[diff] [blame]2986
2987<!-- _______________________________________________________________________ -->
2988<div class="doc_subsubsection">
Chris Lattnerd04cb6d2009-10-28 00:19:10 +0000[diff] [blame]2989 <a name="i_indirectbr">'<tt>indirectbr</tt>' Instruction</a>
Chris Lattner3ed871f2009-10-27 19:13:16 +0000[diff] [blame]2990</div>
2991
2992<div class="doc_text">
2993
2994<h5>Syntax:</h5>
2995<pre>
Chris Lattnerd04cb6d2009-10-28 00:19:10 +0000[diff] [blame]2996 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]2997</pre>
2998
2999<h5>Overview:</h5>
3000
Chris Lattnerd04cb6d2009-10-28 00:19:10 +0000[diff] [blame]3001<p>The '<tt>indirectbr</tt>' instruction implements an indirect branch to a label
Chris Lattner3ed871f2009-10-27 19:13:16 +0000[diff] [blame]3002 within the current function, whose address is specified by
Chris Lattnere4801f72009-10-27 21:01:34 +0000[diff] [blame]3003 "<tt>address</tt>". Address must be derived from a <a
3004 href="#blockaddress">blockaddress</a> constant.</p>
Chris Lattner3ed871f2009-10-27 19:13:16 +0000[diff] [blame]3005
3006<h5>Arguments:</h5>
3007
3008<p>The '<tt>address</tt>' argument is the address of the label to jump to. The
3009 rest of the arguments indicate the full set of possible destinations that the
3010 address may point to. Blocks are allowed to occur multiple times in the
3011 destination list, though this isn't particularly useful.</p>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3012
Chris Lattner3ed871f2009-10-27 19:13:16 +0000[diff] [blame]3013<p>This destination list is required so that dataflow analysis has an accurate
3014 understanding of the CFG.</p>
3015
3016<h5>Semantics:</h5>
3017
3018<p>Control transfers to the block specified in the address argument. All
3019 possible destination blocks must be listed in the label list, otherwise this
3020 instruction has undefined behavior. This implies that jumps to labels
3021 defined in other functions have undefined behavior as well.</p>
3022
3023<h5>Implementation:</h5>
3024
3025<p>This is typically implemented with a jump through a register.</p>
3026
3027<h5>Example:</h5>
3028<pre>
Chris Lattnerd04cb6d2009-10-28 00:19:10 +0000[diff] [blame]3029 indirectbr i8* %Addr, [ label %bb1, label %bb2, label %bb3 ]
Chris Lattner3ed871f2009-10-27 19:13:16 +0000[diff] [blame]3030</pre>
3031
3032</div>
3033
3034
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3035<!-- _______________________________________________________________________ -->
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3036<div class="doc_subsubsection">
3037 <a name="i_invoke">'<tt>invoke</tt>' Instruction</a>
3038</div>
3039
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3040<div class="doc_text">
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3041
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3042<h5>Syntax:</h5>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3043<pre>
Devang Patel02256232008-10-07 17:48:33 +0000[diff] [blame]3044 &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]3045 to label &lt;normal label&gt; unwind label &lt;exception label&gt;
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3046</pre>
3047
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]3048<h5>Overview:</h5>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3049<p>The '<tt>invoke</tt>' instruction causes control to transfer to a specified
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3050 function, with the possibility of control flow transfer to either the
3051 '<tt>normal</tt>' label or the '<tt>exception</tt>' label. If the callee
3052 function returns with the "<tt><a href="#i_ret">ret</a></tt>" instruction,
3053 control flow will return to the "normal" label. If the callee (or any
3054 indirect callees) returns with the "<a href="#i_unwind"><tt>unwind</tt></a>"
3055 instruction, control is interrupted and continued at the dynamically nearest
3056 "exception" label.</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3057
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3058<h5>Arguments:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3059<p>This instruction requires several arguments:</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3060
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3061<ol>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3062 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
3063 convention</a> the call should use. If none is specified, the call
3064 defaults to using C calling conventions.</li>
Devang Patel7e9b05e2008-10-06 18:50:38 +0000[diff] [blame]3065
3066 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3067 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
3068 '<tt>inreg</tt>' attributes are valid here.</li>
Devang Patel7e9b05e2008-10-06 18:50:38 +0000[diff] [blame]3069
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3070 <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]3071 function value being invoked. In most cases, this is a direct function
3072 invocation, but indirect <tt>invoke</tt>s are just as possible, branching
3073 off an arbitrary pointer to function value.</li>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3074
3075 <li>'<tt>function ptr val</tt>': An LLVM value containing a pointer to a
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3076 function to be invoked. </li>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3077
3078 <li>'<tt>function args</tt>': argument list whose types match the function
Chris Lattner47f2a832010-03-02 06:36:51 +0000[diff] [blame]3079 signature argument types and parameter attributes. All arguments must be
3080 of <a href="#t_firstclass">first class</a> type. If the function
3081 signature indicates the function accepts a variable number of arguments,
3082 the extra arguments can be specified.</li>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3083
3084 <li>'<tt>normal label</tt>': the label reached when the called function
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3085 executes a '<tt><a href="#i_ret">ret</a></tt>' instruction. </li>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3086
3087 <li>'<tt>exception label</tt>': the label reached when a callee returns with
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3088 the <a href="#i_unwind"><tt>unwind</tt></a> instruction. </li>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3089
Devang Patel02256232008-10-07 17:48:33 +0000[diff] [blame]3090 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3091 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
3092 '<tt>readnone</tt>' attributes are valid here.</li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3093</ol>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3094
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3095<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3096<p>This instruction is designed to operate as a standard
3097 '<tt><a href="#i_call">call</a></tt>' instruction in most regards. The
3098 primary difference is that it establishes an association with a label, which
3099 is used by the runtime library to unwind the stack.</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3100
3101<p>This instruction is used in languages with destructors to ensure that proper
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3102 cleanup is performed in the case of either a <tt>longjmp</tt> or a thrown
3103 exception. Additionally, this is important for implementation of
3104 '<tt>catch</tt>' clauses in high-level languages that support them.</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3105
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3106<p>For the purposes of the SSA form, the definition of the value returned by the
3107 '<tt>invoke</tt>' instruction is deemed to occur on the edge from the current
3108 block to the "normal" label. If the callee unwinds then no return value is
3109 available.</p>
Dan Gohman9069d892009-05-22 21:47:08 +0000[diff] [blame]3110
Chris Lattner97257f82010-01-15 18:08:37 +0000[diff] [blame]3111<p>Note that the code generator does not yet completely support unwind, and
3112that the invoke/unwind semantics are likely to change in future versions.</p>
3113
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3114<h5>Example:</h5>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3115<pre>
Nick Lewycky084ab472008-03-16 07:18:12 +0000[diff] [blame]3116 %retval = invoke i32 @Test(i32 15) to label %Continue
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]3117 unwind label %TestCleanup <i>; {i32}:retval set</i>
Nick Lewycky084ab472008-03-16 07:18:12 +0000[diff] [blame]3118 %retval = invoke <a href="#callingconv">coldcc</a> i32 %Testfnptr(i32 15) to label %Continue
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]3119 unwind label %TestCleanup <i>; {i32}:retval set</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3120</pre>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3121
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3122</div>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3123
Chris Lattner5ed60612003-09-03 00:41:47 +0000[diff] [blame]3124<!-- _______________________________________________________________________ -->
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3125
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3126<div class="doc_subsubsection"> <a name="i_unwind">'<tt>unwind</tt>'
3127Instruction</a> </div>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3128
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3129<div class="doc_text">
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3130
Chris Lattner5ed60612003-09-03 00:41:47 +0000[diff] [blame]3131<h5>Syntax:</h5>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3132<pre>
3133 unwind
3134</pre>
3135
Chris Lattner5ed60612003-09-03 00:41:47 +0000[diff] [blame]3136<h5>Overview:</h5>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3137<p>The '<tt>unwind</tt>' instruction unwinds the stack, continuing control flow
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3138 at the first callee in the dynamic call stack which used
3139 an <a href="#i_invoke"><tt>invoke</tt></a> instruction to perform the call.
3140 This is primarily used to implement exception handling.</p>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3141
Chris Lattner5ed60612003-09-03 00:41:47 +0000[diff] [blame]3142<h5>Semantics:</h5>
Chris Lattnerfe8519c2008-04-19 21:01:16 +0000[diff] [blame]3143<p>The '<tt>unwind</tt>' instruction causes execution of the current function to
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3144 immediately halt. The dynamic call stack is then searched for the
3145 first <a href="#i_invoke"><tt>invoke</tt></a> instruction on the call stack.
3146 Once found, execution continues at the "exceptional" destination block
3147 specified by the <tt>invoke</tt> instruction. If there is no <tt>invoke</tt>
3148 instruction in the dynamic call chain, undefined behavior results.</p>
3149
Chris Lattner97257f82010-01-15 18:08:37 +0000[diff] [blame]3150<p>Note that the code generator does not yet completely support unwind, and
3151that the invoke/unwind semantics are likely to change in future versions.</p>
3152
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3153</div>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3154
3155<!-- _______________________________________________________________________ -->
3156
3157<div class="doc_subsubsection"> <a name="i_unreachable">'<tt>unreachable</tt>'
3158Instruction</a> </div>
3159
3160<div class="doc_text">
3161
3162<h5>Syntax:</h5>
3163<pre>
3164 unreachable
3165</pre>
3166
3167<h5>Overview:</h5>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3168<p>The '<tt>unreachable</tt>' instruction has no defined semantics. This
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3169 instruction is used to inform the optimizer that a particular portion of the
3170 code is not reachable. This can be used to indicate that the code after a
3171 no-return function cannot be reached, and other facts.</p>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3172
3173<h5>Semantics:</h5>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3174<p>The '<tt>unreachable</tt>' instruction has no defined semantics.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3175
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3176</div>
3177
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3178<!-- ======================================================================= -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3179<div class="doc_subsection"> <a name="binaryops">Binary Operations</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3180
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3181<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3182
3183<p>Binary operators are used to do most of the computation in a program. They
3184 require two operands of the same type, execute an operation on them, and
3185 produce a single value. The operands might represent multiple data, as is
3186 the case with the <a href="#t_vector">vector</a> data type. The result value
3187 has the same type as its operands.</p>
3188
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3189<p>There are several different binary operators:</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3190
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3191</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3192
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3193<!-- _______________________________________________________________________ -->
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3194<div class="doc_subsubsection">
3195 <a name="i_add">'<tt>add</tt>' Instruction</a>
3196</div>
3197
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3198<div class="doc_text">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3199
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3200<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3201<pre>
Dan Gohmanb07de442009-07-20 22:41:19 +0000[diff] [blame]3202 &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]3203 &lt;result&gt; = add nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3204 &lt;result&gt; = add nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3205 &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]3206</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3207
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3208<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3209<p>The '<tt>add</tt>' instruction returns the sum of its two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3210
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3211<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3212<p>The two arguments to the '<tt>add</tt>' instruction must
3213 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3214 integer values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3215
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3216<h5>Semantics:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3217<p>The value produced is the integer sum of the two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3218
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3219<p>If the sum has unsigned overflow, the result returned is the mathematical
3220 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]3221
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3222<p>Because LLVM integers use a two's complement representation, this instruction
3223 is appropriate for both signed and unsigned integers.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3224
Dan Gohman902dfff2009-07-22 22:44:56 +0000[diff] [blame]3225<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3226 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3227 <tt>nsw</tt> keywords are present, the result value of the <tt>add</tt>
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]3228 is a <a href="#trapvalues">trap value</a> if unsigned and/or signed overflow,
3229 respectively, occurs.</p>
Dan Gohmanb07de442009-07-20 22:41:19 +0000[diff] [blame]3230
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3231<h5>Example:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3232<pre>
3233 &lt;result&gt; = add i32 4, %var <i>; yields {i32}:result = 4 + %var</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3234</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3235
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3236</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3237
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3238<!-- _______________________________________________________________________ -->
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3239<div class="doc_subsubsection">
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3240 <a name="i_fadd">'<tt>fadd</tt>' Instruction</a>
3241</div>
3242
3243<div class="doc_text">
3244
3245<h5>Syntax:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3246<pre>
3247 &lt;result&gt; = fadd &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3248</pre>
3249
3250<h5>Overview:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3251<p>The '<tt>fadd</tt>' instruction returns the sum of its two operands.</p>
3252
3253<h5>Arguments:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3254<p>The two arguments to the '<tt>fadd</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3255 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3256 floating point values. Both arguments must have identical types.</p>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3257
3258<h5>Semantics:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3259<p>The value produced is the floating point sum of the two operands.</p>
3260
3261<h5>Example:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3262<pre>
3263 &lt;result&gt; = fadd float 4.0, %var <i>; yields {float}:result = 4.0 + %var</i>
3264</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3265
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3266</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3267
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3268<!-- _______________________________________________________________________ -->
3269<div class="doc_subsubsection">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3270 <a name="i_sub">'<tt>sub</tt>' Instruction</a>
3271</div>
3272
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3273<div class="doc_text">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3274
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3275<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3276<pre>
Dan Gohman902dfff2009-07-22 22:44:56 +0000[diff] [blame]3277 &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]3278 &lt;result&gt; = sub nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3279 &lt;result&gt; = sub nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3280 &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]3281</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3282
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3283<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3284<p>The '<tt>sub</tt>' instruction returns the difference of its two
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3285 operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3286
3287<p>Note that the '<tt>sub</tt>' instruction is used to represent the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3288 '<tt>neg</tt>' instruction present in most other intermediate
3289 representations.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3290
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3291<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3292<p>The two arguments to the '<tt>sub</tt>' instruction must
3293 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3294 integer values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3295
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3296<h5>Semantics:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3297<p>The value produced is the integer difference of the two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3298
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3299<p>If the difference has unsigned overflow, the result returned is the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3300 mathematical result modulo 2<sup>n</sup>, where n is the bit width of the
3301 result.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3302
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3303<p>Because LLVM integers use a two's complement representation, this instruction
3304 is appropriate for both signed and unsigned integers.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3305
Dan Gohman902dfff2009-07-22 22:44:56 +0000[diff] [blame]3306<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3307 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3308 <tt>nsw</tt> keywords are present, the result value of the <tt>sub</tt>
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]3309 is a <a href="#trapvalues">trap value</a> if unsigned and/or signed overflow,
3310 respectively, occurs.</p>
Dan Gohmanb07de442009-07-20 22:41:19 +0000[diff] [blame]3311
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3312<h5>Example:</h5>
Bill Wendling2d8b9a82007-05-29 09:42:13 +0000[diff] [blame]3313<pre>
3314 &lt;result&gt; = sub i32 4, %var <i>; yields {i32}:result = 4 - %var</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3315 &lt;result&gt; = sub i32 0, %val <i>; yields {i32}:result = -%var</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3316</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3317
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3318</div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3319
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3320<!-- _______________________________________________________________________ -->
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3321<div class="doc_subsubsection">
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3322 <a name="i_fsub">'<tt>fsub</tt>' Instruction</a>
3323</div>
3324
3325<div class="doc_text">
3326
3327<h5>Syntax:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3328<pre>
3329 &lt;result&gt; = fsub &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3330</pre>
3331
3332<h5>Overview:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3333<p>The '<tt>fsub</tt>' instruction returns the difference of its two
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3334 operands.</p>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3335
3336<p>Note that the '<tt>fsub</tt>' instruction is used to represent the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3337 '<tt>fneg</tt>' instruction present in most other intermediate
3338 representations.</p>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3339
3340<h5>Arguments:</h5>
Bill Wendling972b7202009-07-20 02:32:41 +0000[diff] [blame]3341<p>The two arguments to the '<tt>fsub</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3342 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3343 floating point values. Both arguments must have identical types.</p>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3344
3345<h5>Semantics:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3346<p>The value produced is the floating point difference of the two operands.</p>
3347
3348<h5>Example:</h5>
3349<pre>
3350 &lt;result&gt; = fsub float 4.0, %var <i>; yields {float}:result = 4.0 - %var</i>
3351 &lt;result&gt; = fsub float -0.0, %val <i>; yields {float}:result = -%var</i>
3352</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3353
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3354</div>
3355
3356<!-- _______________________________________________________________________ -->
3357<div class="doc_subsubsection">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3358 <a name="i_mul">'<tt>mul</tt>' Instruction</a>
3359</div>
3360
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3361<div class="doc_text">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3362
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3363<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3364<pre>
Dan Gohman902dfff2009-07-22 22:44:56 +0000[diff] [blame]3365 &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]3366 &lt;result&gt; = mul nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3367 &lt;result&gt; = mul nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3368 &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]3369</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3370
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3371<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3372<p>The '<tt>mul</tt>' instruction returns the product of its two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3373
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3374<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3375<p>The two arguments to the '<tt>mul</tt>' instruction must
3376 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3377 integer values. Both arguments must have identical types.</p>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3378
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3379<h5>Semantics:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3380<p>The value produced is the integer product of the two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3381
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3382<p>If the result of the multiplication has unsigned overflow, the result
3383 returned is the mathematical result modulo 2<sup>n</sup>, where n is the bit
3384 width of the result.</p>
3385
3386<p>Because LLVM integers use a two's complement representation, and the result
3387 is the same width as the operands, this instruction returns the correct
3388 result for both signed and unsigned integers. If a full product
3389 (e.g. <tt>i32</tt>x<tt>i32</tt>-><tt>i64</tt>) is needed, the operands should
3390 be sign-extended or zero-extended as appropriate to the width of the full
3391 product.</p>
3392
Dan Gohman902dfff2009-07-22 22:44:56 +0000[diff] [blame]3393<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3394 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3395 <tt>nsw</tt> keywords are present, the result value of the <tt>mul</tt>
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]3396 is a <a href="#trapvalues">trap value</a> if unsigned and/or signed overflow,
3397 respectively, occurs.</p>
Dan Gohmanb07de442009-07-20 22:41:19 +0000[diff] [blame]3398
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3399<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3400<pre>
3401 &lt;result&gt; = mul i32 4, %var <i>; yields {i32}:result = 4 * %var</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3402</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3403
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3404</div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3405
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3406<!-- _______________________________________________________________________ -->
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3407<div class="doc_subsubsection">
3408 <a name="i_fmul">'<tt>fmul</tt>' Instruction</a>
3409</div>
3410
3411<div class="doc_text">
3412
3413<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3414<pre>
3415 &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]3416</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3417
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3418<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3419<p>The '<tt>fmul</tt>' instruction returns the product of its two operands.</p>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3420
3421<h5>Arguments:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3422<p>The two arguments to the '<tt>fmul</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3423 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3424 floating point values. Both arguments must have identical types.</p>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3425
3426<h5>Semantics:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3427<p>The value produced is the floating point product of the two operands.</p>
3428
3429<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3430<pre>
3431 &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]3432</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3433
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3434</div>
3435
3436<!-- _______________________________________________________________________ -->
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3437<div class="doc_subsubsection"> <a name="i_udiv">'<tt>udiv</tt>' Instruction
3438</a></div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3439
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3440<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3441
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3442<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3443<pre>
Chris Lattner35315d02011-02-06 21:44:57 +0000[diff] [blame^]3444 &lt;result&gt; = udiv &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3445 &lt;result&gt; = udiv exact &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3446</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3447
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3448<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3449<p>The '<tt>udiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3450
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3451<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3452<p>The two arguments to the '<tt>udiv</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3453 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3454 values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3455
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3456<h5>Semantics:</h5>
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3457<p>The value produced is the unsigned integer quotient of the two operands.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3458
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3459<p>Note that unsigned integer division and signed integer division are distinct
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3460 operations; for signed integer division, use '<tt>sdiv</tt>'.</p>
3461
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3462<p>Division by zero leads to undefined behavior.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3463
Chris Lattner35315d02011-02-06 21:44:57 +0000[diff] [blame^]3464<p>If the <tt>exact</tt> keyword is present, the result value of the
3465 <tt>udiv</tt> is a <a href="#trapvalues">trap value</a> if %op1 is not a
3466 multiple of %op2 (as such, "((a udiv exact b) mul b) == a").</p>
3467
3468
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3469<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3470<pre>
3471 &lt;result&gt; = udiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3472</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3473
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3474</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3475
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3476<!-- _______________________________________________________________________ -->
3477<div class="doc_subsubsection"> <a name="i_sdiv">'<tt>sdiv</tt>' Instruction
3478</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3479
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3480<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3481
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3482<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3483<pre>
Dan Gohmanb07de442009-07-20 22:41:19 +0000[diff] [blame]3484 &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]3485 &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]3486</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3487
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3488<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3489<p>The '<tt>sdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3490
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3491<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3492<p>The two arguments to the '<tt>sdiv</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3493 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3494 values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3495
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3496<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3497<p>The value produced is the signed integer quotient of the two operands rounded
3498 towards zero.</p>
3499
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3500<p>Note that signed integer division and unsigned integer division are distinct
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3501 operations; for unsigned integer division, use '<tt>udiv</tt>'.</p>
3502
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3503<p>Division by zero leads to undefined behavior. Overflow also leads to
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3504 undefined behavior; this is a rare case, but can occur, for example, by doing
3505 a 32-bit division of -2147483648 by -1.</p>
3506
Dan Gohman71dfd782009-07-22 00:04:19 +0000[diff] [blame]3507<p>If the <tt>exact</tt> keyword is present, the result value of the
Dan Gohman57255802010-04-23 15:23:32 +0000[diff] [blame]3508 <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]3509 be rounded.</p>
Dan Gohmanb07de442009-07-20 22:41:19 +0000[diff] [blame]3510
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3511<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3512<pre>
3513 &lt;result&gt; = sdiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3514</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3515
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3516</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3517
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3518<!-- _______________________________________________________________________ -->
3519<div class="doc_subsubsection"> <a name="i_fdiv">'<tt>fdiv</tt>'
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3520Instruction</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3521
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3522<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3523
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3524<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3525<pre>
Gabor Greif0f75ad02008-08-07 21:46:00 +0000[diff] [blame]3526 &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]3527</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3528
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3529<h5>Overview:</h5>
3530<p>The '<tt>fdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3531
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3532<h5>Arguments:</h5>
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]3533<p>The two arguments to the '<tt>fdiv</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3534 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3535 floating point values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3536
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3537<h5>Semantics:</h5>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3538<p>The value produced is the floating point quotient of the two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3539
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3540<h5>Example:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3541<pre>
3542 &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]3543</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3544
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3545</div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3546
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3547<!-- _______________________________________________________________________ -->
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3548<div class="doc_subsubsection"> <a name="i_urem">'<tt>urem</tt>' Instruction</a>
3549</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3550
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3551<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3552
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3553<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3554<pre>
3555 &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]3556</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3557
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3558<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3559<p>The '<tt>urem</tt>' instruction returns the remainder from the unsigned
3560 division of its two arguments.</p>
3561
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3562<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3563<p>The two arguments to the '<tt>urem</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3564 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3565 values. Both arguments must have identical types.</p>
3566
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3567<h5>Semantics:</h5>
3568<p>This instruction returns the unsigned integer <i>remainder</i> of a division.
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3569 This instruction always performs an unsigned division to get the
3570 remainder.</p>
3571
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3572<p>Note that unsigned integer remainder and signed integer remainder are
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3573 distinct operations; for signed integer remainder, use '<tt>srem</tt>'.</p>
3574
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3575<p>Taking the remainder of a division by zero leads to undefined behavior.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3576
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3577<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3578<pre>
3579 &lt;result&gt; = urem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3580</pre>
3581
3582</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3583
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3584<!-- _______________________________________________________________________ -->
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3585<div class="doc_subsubsection">
3586 <a name="i_srem">'<tt>srem</tt>' Instruction</a>
3587</div>
3588
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3589<div class="doc_text">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3590
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3591<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3592<pre>
Gabor Greif0f75ad02008-08-07 21:46:00 +0000[diff] [blame]3593 &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]3594</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3595
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3596<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3597<p>The '<tt>srem</tt>' instruction returns the remainder from the signed
3598 division of its two operands. This instruction can also take
3599 <a href="#t_vector">vector</a> versions of the values in which case the
3600 elements must be integers.</p>
Chris Lattnerb8f816e2008-01-04 04:33:49 +0000[diff] [blame]3601
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3602<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3603<p>The two arguments to the '<tt>srem</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3604 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3605 values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3606
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3607<h5>Semantics:</h5>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3608<p>This instruction returns the <i>remainder</i> of a division (where the result
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3609 has the same sign as the dividend, <tt>op1</tt>), not the <i>modulo</i>
3610 operator (where the result has the same sign as the divisor, <tt>op2</tt>) of
3611 a value. For more information about the difference,
3612 see <a href="http://mathforum.org/dr.math/problems/anne.4.28.99.html">The
3613 Math Forum</a>. For a table of how this is implemented in various languages,
3614 please see <a href="http://en.wikipedia.org/wiki/Modulo_operation">
3615 Wikipedia: modulo operation</a>.</p>
3616
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3617<p>Note that signed integer remainder and unsigned integer remainder are
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3618 distinct operations; for unsigned integer remainder, use '<tt>urem</tt>'.</p>
3619
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3620<p>Taking the remainder of a division by zero leads to undefined behavior.
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3621 Overflow also leads to undefined behavior; this is a rare case, but can
3622 occur, for example, by taking the remainder of a 32-bit division of
3623 -2147483648 by -1. (The remainder doesn't actually overflow, but this rule
3624 lets srem be implemented using instructions that return both the result of
3625 the division and the remainder.)</p>
3626
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3627<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3628<pre>
3629 &lt;result&gt; = srem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3630</pre>
3631
3632</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3633
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3634<!-- _______________________________________________________________________ -->
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3635<div class="doc_subsubsection">
3636 <a name="i_frem">'<tt>frem</tt>' Instruction</a> </div>
3637
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3638<div class="doc_text">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3639
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3640<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3641<pre>
3642 &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]3643</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3644
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3645<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3646<p>The '<tt>frem</tt>' instruction returns the remainder from the division of
3647 its two operands.</p>
3648
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3649<h5>Arguments:</h5>
3650<p>The two arguments to the '<tt>frem</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3651 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3652 floating point values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3653
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3654<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3655<p>This instruction returns the <i>remainder</i> of a division. The remainder
3656 has the same sign as the dividend.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3657
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3658<h5>Example:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3659<pre>
3660 &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]3661</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3662
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3663</div>
Robert Bocchino820bc75b2006-02-17 21:18:08 +0000[diff] [blame]3664
Reid Spencer2ab01932007-02-02 13:57:07 +0000[diff] [blame]3665<!-- ======================================================================= -->
3666<div class="doc_subsection"> <a name="bitwiseops">Bitwise Binary
3667Operations</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3668
Reid Spencer2ab01932007-02-02 13:57:07 +0000[diff] [blame]3669<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3670
3671<p>Bitwise binary operators are used to do various forms of bit-twiddling in a
3672 program. They are generally very efficient instructions and can commonly be
3673 strength reduced from other instructions. They require two operands of the
3674 same type, execute an operation on them, and produce a single value. The
3675 resulting value is the same type as its operands.</p>
3676
Reid Spencer2ab01932007-02-02 13:57:07 +0000[diff] [blame]3677</div>
3678
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3679<!-- _______________________________________________________________________ -->
3680<div class="doc_subsubsection"> <a name="i_shl">'<tt>shl</tt>'
3681Instruction</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3682
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3683<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3684
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3685<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3686<pre>
3687 &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]3688</pre>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]3689
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3690<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3691<p>The '<tt>shl</tt>' instruction returns the first operand shifted to the left
3692 a specified number of bits.</p>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]3693
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3694<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3695<p>Both arguments to the '<tt>shl</tt>' instruction must be the
3696 same <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3697 integer type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3698
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3699<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3700<p>The value produced is <tt>op1</tt> * 2<sup><tt>op2</tt></sup> mod
3701 2<sup>n</sup>, where <tt>n</tt> is the width of the result. If <tt>op2</tt>
3702 is (statically or dynamically) negative or equal to or larger than the number
3703 of bits in <tt>op1</tt>, the result is undefined. If the arguments are
3704 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
3705 shift amount in <tt>op2</tt>.</p>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]3706
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3707<h5>Example:</h5>
3708<pre>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3709 &lt;result&gt; = shl i32 4, %var <i>; yields {i32}: 4 &lt;&lt; %var</i>
3710 &lt;result&gt; = shl i32 4, 2 <i>; yields {i32}: 16</i>
3711 &lt;result&gt; = shl i32 1, 10 <i>; yields {i32}: 1024</i>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]3712 &lt;result&gt; = shl i32 1, 32 <i>; undefined</i>
Mon P Wang4dd832d2008-12-09 05:46:39 +0000[diff] [blame]3713 &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]3714</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3715
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3716</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3717
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3718<!-- _______________________________________________________________________ -->
3719<div class="doc_subsubsection"> <a name="i_lshr">'<tt>lshr</tt>'
3720Instruction</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3721
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3722<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3723
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3724<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3725<pre>
3726 &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]3727</pre>
3728
3729<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3730<p>The '<tt>lshr</tt>' instruction (logical shift right) returns the first
3731 operand shifted to the right a specified number of bits with zero fill.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3732
3733<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3734<p>Both arguments to the '<tt>lshr</tt>' instruction must be the same
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3735 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3736 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3737
3738<h5>Semantics:</h5>
3739<p>This instruction always performs a logical shift right operation. The most
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3740 significant bits of the result will be filled with zero bits after the shift.
3741 If <tt>op2</tt> is (statically or dynamically) equal to or larger than the
3742 number of bits in <tt>op1</tt>, the result is undefined. If the arguments are
3743 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
3744 shift amount in <tt>op2</tt>.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3745
3746<h5>Example:</h5>
3747<pre>
3748 &lt;result&gt; = lshr i32 4, 1 <i>; yields {i32}:result = 2</i>
3749 &lt;result&gt; = lshr i32 4, 2 <i>; yields {i32}:result = 1</i>
3750 &lt;result&gt; = lshr i8 4, 3 <i>; yields {i8}:result = 0</i>
3751 &lt;result&gt; = lshr i8 -2, 1 <i>; yields {i8}:result = 0x7FFFFFFF </i>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]3752 &lt;result&gt; = lshr i32 1, 32 <i>; undefined</i>
Mon P Wang4dd832d2008-12-09 05:46:39 +0000[diff] [blame]3753 &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]3754</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3755
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3756</div>
3757
Reid Spencer2ab01932007-02-02 13:57:07 +0000[diff] [blame]3758<!-- _______________________________________________________________________ -->
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3759<div class="doc_subsubsection"> <a name="i_ashr">'<tt>ashr</tt>'
3760Instruction</a> </div>
3761<div class="doc_text">
3762
3763<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3764<pre>
3765 &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]3766</pre>
3767
3768<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3769<p>The '<tt>ashr</tt>' instruction (arithmetic shift right) returns the first
3770 operand shifted to the right a specified number of bits with sign
3771 extension.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3772
3773<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3774<p>Both arguments to the '<tt>ashr</tt>' instruction must be the same
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3775 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3776 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3777
3778<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3779<p>This instruction always performs an arithmetic shift right operation, The
3780 most significant bits of the result will be filled with the sign bit
3781 of <tt>op1</tt>. If <tt>op2</tt> is (statically or dynamically) equal to or
3782 larger than the number of bits in <tt>op1</tt>, the result is undefined. If
3783 the arguments are vectors, each vector element of <tt>op1</tt> is shifted by
3784 the corresponding shift amount in <tt>op2</tt>.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3785
3786<h5>Example:</h5>
3787<pre>
3788 &lt;result&gt; = ashr i32 4, 1 <i>; yields {i32}:result = 2</i>
3789 &lt;result&gt; = ashr i32 4, 2 <i>; yields {i32}:result = 1</i>
3790 &lt;result&gt; = ashr i8 4, 3 <i>; yields {i8}:result = 0</i>
3791 &lt;result&gt; = ashr i8 -2, 1 <i>; yields {i8}:result = -1</i>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]3792 &lt;result&gt; = ashr i32 1, 32 <i>; undefined</i>
Mon P Wang4dd832d2008-12-09 05:46:39 +0000[diff] [blame]3793 &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]3794</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3795
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3796</div>
3797
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3798<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3799<div class="doc_subsubsection"> <a name="i_and">'<tt>and</tt>'
3800Instruction</a> </div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3801
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3802<div class="doc_text">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3803
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3804<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3805<pre>
Gabor Greif0f75ad02008-08-07 21:46:00 +0000[diff] [blame]3806 &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]3807</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3808
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3809<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3810<p>The '<tt>and</tt>' instruction returns the bitwise logical and of its two
3811 operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3812
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3813<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3814<p>The two arguments to the '<tt>and</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3815 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3816 values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3817
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3818<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3819<p>The truth table used for the '<tt>and</tt>' instruction is:</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3820
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3821<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3822 <tbody>
3823 <tr>
3824 <td>In0</td>
3825 <td>In1</td>
3826 <td>Out</td>
3827 </tr>
3828 <tr>
3829 <td>0</td>
3830 <td>0</td>
3831 <td>0</td>
3832 </tr>
3833 <tr>
3834 <td>0</td>
3835 <td>1</td>
3836 <td>0</td>
3837 </tr>
3838 <tr>
3839 <td>1</td>
3840 <td>0</td>
3841 <td>0</td>
3842 </tr>
3843 <tr>
3844 <td>1</td>
3845 <td>1</td>
3846 <td>1</td>
3847 </tr>
3848 </tbody>
3849</table>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3850
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3851<h5>Example:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3852<pre>
3853 &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]3854 &lt;result&gt; = and i32 15, 40 <i>; yields {i32}:result = 8</i>
3855 &lt;result&gt; = and i32 4, 8 <i>; yields {i32}:result = 0</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3856</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3857</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3858<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3859<div class="doc_subsubsection"> <a name="i_or">'<tt>or</tt>' Instruction</a> </div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3860
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3861<div class="doc_text">
3862
3863<h5>Syntax:</h5>
3864<pre>
3865 &lt;result&gt; = or &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3866</pre>
3867
3868<h5>Overview:</h5>
3869<p>The '<tt>or</tt>' instruction returns the bitwise logical inclusive or of its
3870 two operands.</p>
3871
3872<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3873<p>The two arguments to the '<tt>or</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3874 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3875 values. Both arguments must have identical types.</p>
3876
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3877<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3878<p>The truth table used for the '<tt>or</tt>' instruction is:</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3879
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3880<table border="1" cellspacing="0" cellpadding="4">
3881 <tbody>
3882 <tr>
3883 <td>In0</td>
3884 <td>In1</td>
3885 <td>Out</td>
3886 </tr>
3887 <tr>
3888 <td>0</td>
3889 <td>0</td>
3890 <td>0</td>
3891 </tr>
3892 <tr>
3893 <td>0</td>
3894 <td>1</td>
3895 <td>1</td>
3896 </tr>
3897 <tr>
3898 <td>1</td>
3899 <td>0</td>
3900 <td>1</td>
3901 </tr>
3902 <tr>
3903 <td>1</td>
3904 <td>1</td>
3905 <td>1</td>
3906 </tr>
3907 </tbody>
3908</table>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3909
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3910<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3911<pre>
3912 &lt;result&gt; = or i32 4, %var <i>; yields {i32}:result = 4 | %var</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3913 &lt;result&gt; = or i32 15, 40 <i>; yields {i32}:result = 47</i>
3914 &lt;result&gt; = or i32 4, 8 <i>; yields {i32}:result = 12</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3915</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3916
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3917</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3918
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3919<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3920<div class="doc_subsubsection"> <a name="i_xor">'<tt>xor</tt>'
3921Instruction</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3922
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3923<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3924
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3925<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3926<pre>
3927 &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]3928</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3929
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3930<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3931<p>The '<tt>xor</tt>' instruction returns the bitwise logical exclusive or of
3932 its two operands. The <tt>xor</tt> is used to implement the "one's
3933 complement" operation, which is the "~" operator in C.</p>
3934
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3935<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3936<p>The two arguments to the '<tt>xor</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3937 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3938 values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3939
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3940<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3941<p>The truth table used for the '<tt>xor</tt>' instruction is:</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3942
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3943<table border="1" cellspacing="0" cellpadding="4">
3944 <tbody>
3945 <tr>
3946 <td>In0</td>
3947 <td>In1</td>
3948 <td>Out</td>
3949 </tr>
3950 <tr>
3951 <td>0</td>
3952 <td>0</td>
3953 <td>0</td>
3954 </tr>
3955 <tr>
3956 <td>0</td>
3957 <td>1</td>
3958 <td>1</td>
3959 </tr>
3960 <tr>
3961 <td>1</td>
3962 <td>0</td>
3963 <td>1</td>
3964 </tr>
3965 <tr>
3966 <td>1</td>
3967 <td>1</td>
3968 <td>0</td>
3969 </tr>
3970 </tbody>
3971</table>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3972
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3973<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3974<pre>
3975 &lt;result&gt; = xor i32 4, %var <i>; yields {i32}:result = 4 ^ %var</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3976 &lt;result&gt; = xor i32 15, 40 <i>; yields {i32}:result = 39</i>
3977 &lt;result&gt; = xor i32 4, 8 <i>; yields {i32}:result = 12</i>
3978 &lt;result&gt; = xor i32 %V, -1 <i>; yields {i32}:result = ~%V</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3979</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3980
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3981</div>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3982
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3983<!-- ======================================================================= -->
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3984<div class="doc_subsection">
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]3985 <a name="vectorops">Vector Operations</a>
3986</div>
3987
3988<div class="doc_text">
3989
3990<p>LLVM supports several instructions to represent vector operations in a
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3991 target-independent manner. These instructions cover the element-access and
3992 vector-specific operations needed to process vectors effectively. While LLVM
3993 does directly support these vector operations, many sophisticated algorithms
3994 will want to use target-specific intrinsics to take full advantage of a
3995 specific target.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]3996
3997</div>
3998
3999<!-- _______________________________________________________________________ -->
4000<div class="doc_subsubsection">
4001 <a name="i_extractelement">'<tt>extractelement</tt>' Instruction</a>
4002</div>
4003
4004<div class="doc_text">
4005
4006<h5>Syntax:</h5>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4007<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4008 &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]4009</pre>
4010
4011<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4012<p>The '<tt>extractelement</tt>' instruction extracts a single scalar element
4013 from a vector at a specified index.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4014
4015
4016<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4017<p>The first operand of an '<tt>extractelement</tt>' instruction is a value
4018 of <a href="#t_vector">vector</a> type. The second operand is an index
4019 indicating the position from which to extract the element. The index may be
4020 a variable.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4021
4022<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4023<p>The result is a scalar of the same type as the element type of
4024 <tt>val</tt>. Its value is the value at position <tt>idx</tt> of
4025 <tt>val</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
4026 results are undefined.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4027
4028<h5>Example:</h5>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4029<pre>
Gabor Greif03ab4dc2009-10-28 13:14:50 +0000[diff] [blame]4030 &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]4031</pre>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4032
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4033</div>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4034
4035<!-- _______________________________________________________________________ -->
4036<div class="doc_subsubsection">
4037 <a name="i_insertelement">'<tt>insertelement</tt>' Instruction</a>
4038</div>
4039
4040<div class="doc_text">
4041
4042<h5>Syntax:</h5>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4043<pre>
Dan Gohman43ba0672008-05-12 23:38:42 +0000[diff] [blame]4044 &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]4045</pre>
4046
4047<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4048<p>The '<tt>insertelement</tt>' instruction inserts a scalar element into a
4049 vector at a specified index.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4050
4051<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4052<p>The first operand of an '<tt>insertelement</tt>' instruction is a value
4053 of <a href="#t_vector">vector</a> type. The second operand is a scalar value
4054 whose type must equal the element type of the first operand. The third
4055 operand is an index indicating the position at which to insert the value.
4056 The index may be a variable.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4057
4058<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4059<p>The result is a vector of the same type as <tt>val</tt>. Its element values
4060 are those of <tt>val</tt> except at position <tt>idx</tt>, where it gets the
4061 value <tt>elt</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
4062 results are undefined.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4063
4064<h5>Example:</h5>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4065<pre>
Gabor Greif03ab4dc2009-10-28 13:14:50 +0000[diff] [blame]4066 &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]4067</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4068
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4069</div>
4070
4071<!-- _______________________________________________________________________ -->
4072<div class="doc_subsubsection">
4073 <a name="i_shufflevector">'<tt>shufflevector</tt>' Instruction</a>
4074</div>
4075
4076<div class="doc_text">
4077
4078<h5>Syntax:</h5>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4079<pre>
Mon P Wang25f01062008-11-10 04:46:22 +0000[diff] [blame]4080 &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]4081</pre>
4082
4083<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4084<p>The '<tt>shufflevector</tt>' instruction constructs a permutation of elements
4085 from two input vectors, returning a vector with the same element type as the
4086 input and length that is the same as the shuffle mask.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4087
4088<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4089<p>The first two operands of a '<tt>shufflevector</tt>' instruction are vectors
4090 with types that match each other. The third argument is a shuffle mask whose
4091 element type is always 'i32'. The result of the instruction is a vector
4092 whose length is the same as the shuffle mask and whose element type is the
4093 same as the element type of the first two operands.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4094
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4095<p>The shuffle mask operand is required to be a constant vector with either
4096 constant integer or undef values.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4097
4098<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4099<p>The elements of the two input vectors are numbered from left to right across
4100 both of the vectors. The shuffle mask operand specifies, for each element of
4101 the result vector, which element of the two input vectors the result element
4102 gets. The element selector may be undef (meaning "don't care") and the
4103 second operand may be undef if performing a shuffle from only one vector.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4104
4105<h5>Example:</h5>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4106<pre>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4107 &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]4108 &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]4109 &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]4110 &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]4111 &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]4112 &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]4113 &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]4114 &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]4115</pre>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4116
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4117</div>
Tanya Lattnerb138bbe2006-04-14 19:24:33 +0000[diff] [blame]4118
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4119<!-- ======================================================================= -->
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4120<div class="doc_subsection">
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4121 <a name="aggregateops">Aggregate Operations</a>
4122</div>
4123
4124<div class="doc_text">
4125
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]4126<p>LLVM supports several instructions for working with
4127 <a href="#t_aggregate">aggregate</a> values.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4128
4129</div>
4130
4131<!-- _______________________________________________________________________ -->
4132<div class="doc_subsubsection">
4133 <a name="i_extractvalue">'<tt>extractvalue</tt>' Instruction</a>
4134</div>
4135
4136<div class="doc_text">
4137
4138<h5>Syntax:</h5>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4139<pre>
4140 &lt;result&gt; = extractvalue &lt;aggregate type&gt; &lt;val&gt;, &lt;idx&gt;{, &lt;idx&gt;}*
4141</pre>
4142
4143<h5>Overview:</h5>
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]4144<p>The '<tt>extractvalue</tt>' instruction extracts the value of a member field
4145 from an <a href="#t_aggregate">aggregate</a> value.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4146
4147<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4148<p>The first operand of an '<tt>extractvalue</tt>' instruction is a value
Chris Lattner13ee7952010-08-28 04:09:24 +0000[diff] [blame]4149 of <a href="#t_struct">struct</a> or
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]4150 <a href="#t_array">array</a> type. The operands are constant indices to
4151 specify which value to extract in a similar manner as indices in a
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4152 '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
Frits van Bommel7cf63ac2010-12-05 20:54:38 +0000[diff] [blame]4153 <p>The major differences to <tt>getelementptr</tt> indexing are:</p>
4154 <ul>
4155 <li>Since the value being indexed is not a pointer, the first index is
4156 omitted and assumed to be zero.</li>
4157 <li>At least one index must be specified.</li>
4158 <li>Not only struct indices but also array indices must be in
4159 bounds.</li>
4160 </ul>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4161
4162<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4163<p>The result is the value at the position in the aggregate specified by the
4164 index operands.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4165
4166<h5>Example:</h5>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4167<pre>
Gabor Greif03ab4dc2009-10-28 13:14:50 +0000[diff] [blame]4168 &lt;result&gt; = extractvalue {i32, float} %agg, 0 <i>; yields i32</i>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4169</pre>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4170
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4171</div>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4172
4173<!-- _______________________________________________________________________ -->
4174<div class="doc_subsubsection">
4175 <a name="i_insertvalue">'<tt>insertvalue</tt>' Instruction</a>
4176</div>
4177
4178<div class="doc_text">
4179
4180<h5>Syntax:</h5>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4181<pre>
Jeffrey Yasskinf991bbb2010-01-11 19:19:26 +0000[diff] [blame]4182 &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]4183</pre>
4184
4185<h5>Overview:</h5>
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]4186<p>The '<tt>insertvalue</tt>' instruction inserts a value into a member field
4187 in an <a href="#t_aggregate">aggregate</a> value.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4188
4189<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4190<p>The first operand of an '<tt>insertvalue</tt>' instruction is a value
Chris Lattner13ee7952010-08-28 04:09:24 +0000[diff] [blame]4191 of <a href="#t_struct">struct</a> or
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]4192 <a href="#t_array">array</a> type. The second operand is a first-class
4193 value to insert. The following operands are constant indices indicating
4194 the position at which to insert the value in a similar manner as indices in a
Frits van Bommel7cf63ac2010-12-05 20:54:38 +0000[diff] [blame]4195 '<tt><a href="#i_extractvalue">extractvalue</a></tt>' instruction. The
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4196 value to insert must have the same type as the value identified by the
4197 indices.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4198
4199<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4200<p>The result is an aggregate of the same type as <tt>val</tt>. Its value is
4201 that of <tt>val</tt> except that the value at the position specified by the
4202 indices is that of <tt>elt</tt>.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4203
4204<h5>Example:</h5>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4205<pre>
Jeffrey Yasskinf991bbb2010-01-11 19:19:26 +0000[diff] [blame]4206 %agg1 = insertvalue {i32, float} undef, i32 1, 0 <i>; yields {i32 1, float undef}</i>
4207 %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]4208</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4209
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4210</div>
4211
4212
4213<!-- ======================================================================= -->
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4214<div class="doc_subsection">
Chris Lattner6ab66722006-08-15 00:45:58 +0000[diff] [blame]4215 <a name="memoryops">Memory Access and Addressing Operations</a>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4216</div>
4217
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4218<div class="doc_text">
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4219
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4220<p>A key design point of an SSA-based representation is how it represents
4221 memory. In LLVM, no memory locations are in SSA form, which makes things
Victor Hernandeza70c6df2009-10-26 23:44:29 +0000[diff] [blame]4222 very simple. This section describes how to read, write, and allocate
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4223 memory in LLVM.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4224
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4225</div>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4226
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4227<!-- _______________________________________________________________________ -->
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4228<div class="doc_subsubsection">
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4229 <a name="i_alloca">'<tt>alloca</tt>' Instruction</a>
4230</div>
4231
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4232<div class="doc_text">
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4233
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4234<h5>Syntax:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4235<pre>
Dan Gohman2140a742010-05-28 01:14:11 +0000[diff] [blame]4236 &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]4237</pre>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4238
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4239<h5>Overview:</h5>
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]4240<p>The '<tt>alloca</tt>' instruction allocates memory on the stack frame of the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4241 currently executing function, to be automatically released when this function
4242 returns to its caller. The object is always allocated in the generic address
4243 space (address space zero).</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4244
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4245<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4246<p>The '<tt>alloca</tt>' instruction
4247 allocates <tt>sizeof(&lt;type&gt;)*NumElements</tt> bytes of memory on the
4248 runtime stack, returning a pointer of the appropriate type to the program.
4249 If "NumElements" is specified, it is the number of elements allocated,
4250 otherwise "NumElements" is defaulted to be one. If a constant alignment is
4251 specified, the value result of the allocation is guaranteed to be aligned to
4252 at least that boundary. If not specified, or if zero, the target can choose
4253 to align the allocation on any convenient boundary compatible with the
4254 type.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4255
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4256<p>'<tt>type</tt>' may be any sized type.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4257
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4258<h5>Semantics:</h5>
Bill Wendling9ee6a312009-05-08 20:49:29 +0000[diff] [blame]4259<p>Memory is allocated; a pointer is returned. The operation is undefined if
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4260 there is insufficient stack space for the allocation. '<tt>alloca</tt>'d
4261 memory is automatically released when the function returns. The
4262 '<tt>alloca</tt>' instruction is commonly used to represent automatic
4263 variables that must have an address available. When the function returns
4264 (either with the <tt><a href="#i_ret">ret</a></tt>
4265 or <tt><a href="#i_unwind">unwind</a></tt> instructions), the memory is
4266 reclaimed. Allocating zero bytes is legal, but the result is undefined.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4267
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4268<h5>Example:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4269<pre>
Dan Gohman7a5acb52009-01-04 23:49:44 +0000[diff] [blame]4270 %ptr = alloca i32 <i>; yields {i32*}:ptr</i>
4271 %ptr = alloca i32, i32 4 <i>; yields {i32*}:ptr</i>
4272 %ptr = alloca i32, i32 4, align 1024 <i>; yields {i32*}:ptr</i>
4273 %ptr = alloca i32, align 1024 <i>; yields {i32*}:ptr</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4274</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4275
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4276</div>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4277
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4278<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]4279<div class="doc_subsubsection"> <a name="i_load">'<tt>load</tt>'
4280Instruction</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4281
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4282<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4283
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4284<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4285<pre>
Bill Wendlingbc4024f2010-02-25 21:23:24 +0000[diff] [blame]4286 &lt;result&gt; = load &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;][, !nontemporal !&lt;index&gt;]
4287 &lt;result&gt; = volatile load &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;][, !nontemporal !&lt;index&gt;]
4288 !&lt;index&gt; = !{ i32 1 }
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4289</pre>
4290
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4291<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4292<p>The '<tt>load</tt>' instruction is used to read from memory.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4293
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4294<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4295<p>The argument to the '<tt>load</tt>' instruction specifies the memory address
4296 from which to load. The pointer must point to
4297 a <a href="#t_firstclass">first class</a> type. If the <tt>load</tt> is
4298 marked as <tt>volatile</tt>, then the optimizer is not allowed to modify the
Jeffrey Yasskin5d284ae2010-04-26 21:21:24 +0000[diff] [blame]4299 number or order of execution of this <tt>load</tt> with other <a
4300 href="#volatile">volatile operations</a>.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4301
Bill Wendlingbc4024f2010-02-25 21:23:24 +0000[diff] [blame]4302<p>The optional constant <tt>align</tt> argument specifies the alignment of the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4303 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]4304 omitted <tt>align</tt> argument means that the operation has the preferential
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4305 alignment for the target. It is the responsibility of the code emitter to
4306 ensure that the alignment information is correct. Overestimating the
Bill Wendlingbc4024f2010-02-25 21:23:24 +0000[diff] [blame]4307 alignment results in undefined behavior. Underestimating the alignment may
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4308 produce less efficient code. An alignment of 1 is always safe.</p>
4309
Bill Wendlingbc4024f2010-02-25 21:23:24 +0000[diff] [blame]4310<p>The optional <tt>!nontemporal</tt> metadata must reference a single
4311 metatadata name &lt;index&gt; corresponding to a metadata node with
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]4312 one <tt>i32</tt> entry of value 1. The existence of
Bill Wendlingbc4024f2010-02-25 21:23:24 +0000[diff] [blame]4313 the <tt>!nontemporal</tt> metatadata on the instruction tells the optimizer
4314 and code generator that this load is not expected to be reused in the cache.
4315 The code generator may select special instructions to save cache bandwidth,
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]4316 such as the <tt>MOVNT</tt> instruction on x86.</p>
David Greene9641d062010-02-16 20:50:18 +0000[diff] [blame]4317
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4318<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4319<p>The location of memory pointed to is loaded. If the value being loaded is of
4320 scalar type then the number of bytes read does not exceed the minimum number
4321 of bytes needed to hold all bits of the type. For example, loading an
4322 <tt>i24</tt> reads at most three bytes. When loading a value of a type like
4323 <tt>i20</tt> with a size that is not an integral number of bytes, the result
4324 is undefined if the value was not originally written using a store of the
4325 same type.</p>
4326
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4327<h5>Examples:</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>
4330 <a href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4331 %val = load 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
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4334</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4335
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4336<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]4337<div class="doc_subsubsection"> <a name="i_store">'<tt>store</tt>'
4338Instruction</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4339
Reid Spencera89fb182006-11-09 21:18:01 +0000[diff] [blame]4340<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4341
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4342<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4343<pre>
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]4344 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>
4345 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]4346</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4347
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4348<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4349<p>The '<tt>store</tt>' instruction is used to write to memory.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4350
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4351<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4352<p>There are two arguments to the '<tt>store</tt>' instruction: a value to store
4353 and an address at which to store it. The type of the
4354 '<tt>&lt;pointer&gt;</tt>' operand must be a pointer to
4355 the <a href="#t_firstclass">first class</a> type of the
Jeffrey Yasskin5d284ae2010-04-26 21:21:24 +0000[diff] [blame]4356 '<tt>&lt;value&gt;</tt>' operand. If the <tt>store</tt> is marked as
4357 <tt>volatile</tt>, then the optimizer is not allowed to modify the number or
4358 order of execution of this <tt>store</tt> with other <a
4359 href="#volatile">volatile operations</a>.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4360
4361<p>The optional constant "align" argument specifies the alignment of the
4362 operation (that is, the alignment of the memory address). A value of 0 or an
4363 omitted "align" argument means that the operation has the preferential
4364 alignment for the target. It is the responsibility of the code emitter to
4365 ensure that the alignment information is correct. Overestimating the
4366 alignment results in an undefined behavior. Underestimating the alignment may
4367 produce less efficient code. An alignment of 1 is always safe.</p>
4368
David Greene9641d062010-02-16 20:50:18 +0000[diff] [blame]4369<p>The optional !nontemporal metadata must reference a single metatadata
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]4370 name &lt;index&gt; corresponding to a metadata node with one i32 entry of
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]4371 value 1. The existence of the !nontemporal metatadata on the
David Greene9641d062010-02-16 20:50:18 +0000[diff] [blame]4372 instruction tells the optimizer and code generator that this load is
4373 not expected to be reused in the cache. The code generator may
4374 select special instructions to save cache bandwidth, such as the
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]4375 MOVNT instruction on x86.</p>
David Greene9641d062010-02-16 20:50:18 +0000[diff] [blame]4376
4377
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]4378<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4379<p>The contents of memory are updated to contain '<tt>&lt;value&gt;</tt>' at the
4380 location specified by the '<tt>&lt;pointer&gt;</tt>' operand. If
4381 '<tt>&lt;value&gt;</tt>' is of scalar type then the number of bytes written
4382 does not exceed the minimum number of bytes needed to hold all bits of the
4383 type. For example, storing an <tt>i24</tt> writes at most three bytes. When
4384 writing a value of a type like <tt>i20</tt> with a size that is not an
4385 integral number of bytes, it is unspecified what happens to the extra bits
4386 that do not belong to the type, but they will typically be overwritten.</p>
4387
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4388<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4389<pre>
4390 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Bill Wendling8830ffe2007-10-22 05:10:05 +0000[diff] [blame]4391 store i32 3, i32* %ptr <i>; yields {void}</i>
4392 %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]4393</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4394
Reid Spencer443460a2006-11-09 21:15:49 +0000[diff] [blame]4395</div>
4396
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4397<!-- _______________________________________________________________________ -->
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4398<div class="doc_subsubsection">
4399 <a name="i_getelementptr">'<tt>getelementptr</tt>' Instruction</a>
4400</div>
4401
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4402<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4403
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]4404<h5>Syntax:</h5>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4405<pre>
Matthijs Kooijman0e268272008-10-13 13:44:15 +0000[diff] [blame]4406 &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]4407 &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]4408</pre>
4409
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]4410<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4411<p>The '<tt>getelementptr</tt>' instruction is used to get the address of a
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]4412 subelement of an <a href="#t_aggregate">aggregate</a> data structure.
4413 It performs address calculation only and does not access memory.</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4414
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]4415<h5>Arguments:</h5>
Matthijs Kooijman0e268272008-10-13 13:44:15 +0000[diff] [blame]4416<p>The first argument is always a pointer, and forms the basis of the
Chris Lattnera40b9122009-07-29 06:44:13 +0000[diff] [blame]4417 calculation. The remaining arguments are indices that indicate which of the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4418 elements of the aggregate object are indexed. The interpretation of each
4419 index is dependent on the type being indexed into. The first index always
4420 indexes the pointer value given as the first argument, the second index
4421 indexes a value of the type pointed to (not necessarily the value directly
4422 pointed to, since the first index can be non-zero), etc. The first type
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]4423 indexed into must be a pointer value, subsequent types can be arrays,
Chris Lattner13ee7952010-08-28 04:09:24 +0000[diff] [blame]4424 vectors, and structs. Note that subsequent types being indexed into
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]4425 can never be pointers, since that would require loading the pointer before
4426 continuing calculation.</p>
Matthijs Kooijman0e268272008-10-13 13:44:15 +0000[diff] [blame]4427
4428<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]4429 When indexing into a (optionally packed) structure, only <tt>i32</tt>
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]4430 integer <b>constants</b> are allowed. When indexing into an array, pointer
4431 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]4432 constant.</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4433
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4434<p>For example, let's consider a C code fragment and how it gets compiled to
4435 LLVM:</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4436
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]4437<pre class="doc_code">
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]4438struct RT {
4439 char A;
Chris Lattnera446f1b2007-05-29 15:43:56 +0000[diff] [blame]4440 int B[10][20];
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]4441 char C;
4442};
4443struct ST {
Chris Lattnera446f1b2007-05-29 15:43:56 +0000[diff] [blame]4444 int X;
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]4445 double Y;
4446 struct RT Z;
4447};
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4448
Chris Lattnera446f1b2007-05-29 15:43:56 +0000[diff] [blame]4449int *foo(struct ST *s) {
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]4450 return &amp;s[1].Z.B[5][13];
4451}
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4452</pre>
4453
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4454<p>The LLVM code generated by the GCC frontend is:</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4455
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]4456<pre class="doc_code">
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]4457%RT = <a href="#namedtypes">type</a> { i8 , [10 x [20 x i32]], i8 }
4458%ST = <a href="#namedtypes">type</a> { i32, double, %RT }
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4459
Dan Gohman6b867702009-07-25 02:23:48 +0000[diff] [blame]4460define i32* @foo(%ST* %s) {
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]4461entry:
4462 %reg = getelementptr %ST* %s, i32 1, i32 2, i32 1, i32 5, i32 13
4463 ret i32* %reg
4464}
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4465</pre>
4466
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]4467<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4468<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]4469 type, which is a pointer, yielding a '<tt>%ST</tt>' = '<tt>{ i32, double, %RT
4470 }</tt>' type, a structure. The second index indexes into the third element
4471 of the structure, yielding a '<tt>%RT</tt>' = '<tt>{ i8 , [10 x [20 x i32]],
4472 i8 }</tt>' type, another structure. The third index indexes into the second
4473 element of the structure, yielding a '<tt>[10 x [20 x i32]]</tt>' type, an
4474 array. The two dimensions of the array are subscripted into, yielding an
4475 '<tt>i32</tt>' type. The '<tt>getelementptr</tt>' instruction returns a
4476 pointer to this element, thus computing a value of '<tt>i32*</tt>' type.</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4477
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4478<p>Note that it is perfectly legal to index partially through a structure,
4479 returning a pointer to an inner element. Because of this, the LLVM code for
4480 the given testcase is equivalent to:</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4481
4482<pre>
Dan Gohman6b867702009-07-25 02:23:48 +0000[diff] [blame]4483 define i32* @foo(%ST* %s) {
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4484 %t1 = getelementptr %ST* %s, i32 1 <i>; yields %ST*:%t1</i>
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]4485 %t2 = getelementptr %ST* %t1, i32 0, i32 2 <i>; yields %RT*:%t2</i>
4486 %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]4487 %t4 = getelementptr [10 x [20 x i32]]* %t3, i32 0, i32 5 <i>; yields [20 x i32]*:%t4</i>
4488 %t5 = getelementptr [20 x i32]* %t4, i32 0, i32 13 <i>; yields i32*:%t5</i>
4489 ret i32* %t5
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4490 }
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]4491</pre>
Chris Lattnerc0ad71e2005-06-24 17:22:57 +0000[diff] [blame]4492
Dan Gohman1639c392009-07-27 21:53:46 +0000[diff] [blame]4493<p>If the <tt>inbounds</tt> keyword is present, the result value of the
Dan Gohman57255802010-04-23 15:23:32 +0000[diff] [blame]4494 <tt>getelementptr</tt> is a <a href="#trapvalues">trap value</a> if the
4495 base pointer is not an <i>in bounds</i> address of an allocated object,
4496 or if any of the addresses that would be formed by successive addition of
4497 the offsets implied by the indices to the base address with infinitely
4498 precise arithmetic are not an <i>in bounds</i> address of that allocated
4499 object. The <i>in bounds</i> addresses for an allocated object are all
4500 the addresses that point into the object, plus the address one byte past
4501 the end.</p>
Dan Gohman1639c392009-07-27 21:53:46 +0000[diff] [blame]4502
4503<p>If the <tt>inbounds</tt> keyword is not present, the offsets are added to
4504 the base address with silently-wrapping two's complement arithmetic, and
4505 the result value of the <tt>getelementptr</tt> may be outside the object
4506 pointed to by the base pointer. The result value may not necessarily be
4507 used to access memory though, even if it happens to point into allocated
4508 storage. See the <a href="#pointeraliasing">Pointer Aliasing Rules</a>
4509 section for more information.</p>
4510
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4511<p>The getelementptr instruction is often confusing. For some more insight into
4512 how it works, see <a href="GetElementPtr.html">the getelementptr FAQ</a>.</p>
Chris Lattner6ab66722006-08-15 00:45:58 +0000[diff] [blame]4513
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]4514<h5>Example:</h5>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4515<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4516 <i>; yields [12 x i8]*:aptr</i>
Matthijs Kooijman0e268272008-10-13 13:44:15 +0000[diff] [blame]4517 %aptr = getelementptr {i32, [12 x i8]}* %saptr, i64 0, i32 1
4518 <i>; yields i8*:vptr</i>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]4519 %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]4520 <i>; yields i8*:eptr</i>
4521 %eptr = getelementptr [12 x i8]* %aptr, i64 0, i32 1
Sanjiv Gupta0c155e62009-04-25 07:27:44 +0000[diff] [blame]4522 <i>; yields i32*:iptr</i>
Sanjiv Gupta77abea02009-04-24 16:38:13 +0000[diff] [blame]4523 %iptr = getelementptr [10 x i32]* @arr, i16 0, i16 0
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4524</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4525
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4526</div>
Reid Spencer443460a2006-11-09 21:15:49 +0000[diff] [blame]4527
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4528<!-- ======================================================================= -->
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]4529<div class="doc_subsection"> <a name="convertops">Conversion Operations</a>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4530</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4531
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4532<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4533
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]4534<p>The instructions in this category are the conversion instructions (casting)
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4535 which all take a single operand and a type. They perform various bit
4536 conversions on the operand.</p>
4537
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4538</div>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]4539
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]4540<!-- _______________________________________________________________________ -->
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]4541<div class="doc_subsubsection">
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4542 <a name="i_trunc">'<tt>trunc .. to</tt>' Instruction</a>
4543</div>
4544<div class="doc_text">
4545
4546<h5>Syntax:</h5>
4547<pre>
4548 &lt;result&gt; = trunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4549</pre>
4550
4551<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4552<p>The '<tt>trunc</tt>' instruction truncates its operand to the
4553 type <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4554
4555<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4556<p>The '<tt>trunc</tt>' instruction takes a <tt>value</tt> to trunc, which must
4557 be an <a href="#t_integer">integer</a> type, and a type that specifies the
4558 size and type of the result, which must be
4559 an <a href="#t_integer">integer</a> type. The bit size of <tt>value</tt> must
4560 be larger than the bit size of <tt>ty2</tt>. Equal sized types are not
4561 allowed.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4562
4563<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4564<p>The '<tt>trunc</tt>' instruction truncates the high order bits
4565 in <tt>value</tt> and converts the remaining bits to <tt>ty2</tt>. Since the
4566 source size must be larger than the destination size, <tt>trunc</tt> cannot
4567 be a <i>no-op cast</i>. It will always truncate bits.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4568
4569<h5>Example:</h5>
4570<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4571 %X = trunc i32 257 to i8 <i>; yields i8:1</i>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]4572 %Y = trunc i32 123 to i1 <i>; yields i1:true</i>
Gabor Greiff50fd572009-10-28 09:21:30 +0000[diff] [blame]4573 %Z = trunc i32 122 to i1 <i>; yields i1:false</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4574</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4575
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4576</div>
4577
4578<!-- _______________________________________________________________________ -->
4579<div class="doc_subsubsection">
4580 <a name="i_zext">'<tt>zext .. to</tt>' Instruction</a>
4581</div>
4582<div class="doc_text">
4583
4584<h5>Syntax:</h5>
4585<pre>
4586 &lt;result&gt; = zext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4587</pre>
4588
4589<h5>Overview:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4590<p>The '<tt>zext</tt>' instruction zero extends its operand to type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4591 <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4592
4593
4594<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4595<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]4596 <a href="#t_integer">integer</a> type, and a type to cast it to, which must
4597 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]4598 <tt>value</tt> must be smaller than the bit size of the destination type,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4599 <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4600
4601<h5>Semantics:</h5>
4602<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]4603 bits until it reaches the size of the destination type, <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4604
Reid Spencer07c9c682007-01-12 15:46:11 +0000[diff] [blame]4605<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]4606
4607<h5>Example:</h5>
4608<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4609 %X = zext i32 257 to i64 <i>; yields i64:257</i>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]4610 %Y = zext i1 true to i32 <i>; yields i32:1</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4611</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4612
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4613</div>
4614
4615<!-- _______________________________________________________________________ -->
4616<div class="doc_subsubsection">
4617 <a name="i_sext">'<tt>sext .. to</tt>' Instruction</a>
4618</div>
4619<div class="doc_text">
4620
4621<h5>Syntax:</h5>
4622<pre>
4623 &lt;result&gt; = sext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4624</pre>
4625
4626<h5>Overview:</h5>
4627<p>The '<tt>sext</tt>' sign extends <tt>value</tt> to the type <tt>ty2</tt>.</p>
4628
4629<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4630<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]4631 <a href="#t_integer">integer</a> type, and a type to cast it to, which must
4632 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]4633 <tt>value</tt> must be smaller than the bit size of the destination type,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4634 <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4635
4636<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4637<p>The '<tt>sext</tt>' instruction performs a sign extension by copying the sign
4638 bit (highest order bit) of the <tt>value</tt> until it reaches the bit size
4639 of the type <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4640
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]4641<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]4642
4643<h5>Example:</h5>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4644<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4645 %X = sext i8 -1 to i16 <i>; yields i16 :65535</i>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]4646 %Y = sext i1 true to i32 <i>; yields i32:-1</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4647</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4648
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4649</div>
4650
4651<!-- _______________________________________________________________________ -->
4652<div class="doc_subsubsection">
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]4653 <a name="i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a>
4654</div>
4655
4656<div class="doc_text">
4657
4658<h5>Syntax:</h5>
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]4659<pre>
4660 &lt;result&gt; = fptrunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4661</pre>
4662
4663<h5>Overview:</h5>
4664<p>The '<tt>fptrunc</tt>' instruction truncates <tt>value</tt> to type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4665 <tt>ty2</tt>.</p>
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]4666
4667<h5>Arguments:</h5>
4668<p>The '<tt>fptrunc</tt>' instruction takes a <a href="#t_floating">floating
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4669 point</a> value to cast and a <a href="#t_floating">floating point</a> type
4670 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]4671 <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]4672 <i>no-op cast</i>.</p>
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]4673
4674<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4675<p>The '<tt>fptrunc</tt>' instruction truncates a <tt>value</tt> from a larger
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4676 <a href="#t_floating">floating point</a> type to a smaller
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4677 <a href="#t_floating">floating point</a> type. If the value cannot fit
4678 within the destination type, <tt>ty2</tt>, then the results are
4679 undefined.</p>
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]4680
4681<h5>Example:</h5>
4682<pre>
4683 %X = fptrunc double 123.0 to float <i>; yields float:123.0</i>
4684 %Y = fptrunc double 1.0E+300 to float <i>; yields undefined</i>
4685</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4686
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]4687</div>
4688
4689<!-- _______________________________________________________________________ -->
4690<div class="doc_subsubsection">
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4691 <a name="i_fpext">'<tt>fpext .. to</tt>' Instruction</a>
4692</div>
4693<div class="doc_text">
4694
4695<h5>Syntax:</h5>
4696<pre>
4697 &lt;result&gt; = fpext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4698</pre>
4699
4700<h5>Overview:</h5>
4701<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]4702 floating point value.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4703
4704<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4705<p>The '<tt>fpext</tt>' instruction takes a
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4706 <a href="#t_floating">floating point</a> <tt>value</tt> to cast, and
4707 a <a href="#t_floating">floating point</a> type to cast it to. The source
4708 type must be smaller than the destination type.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4709
4710<h5>Semantics:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]4711<p>The '<tt>fpext</tt>' instruction extends the <tt>value</tt> from a smaller
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4712 <a href="#t_floating">floating point</a> type to a larger
4713 <a href="#t_floating">floating point</a> type. The <tt>fpext</tt> cannot be
4714 used to make a <i>no-op cast</i> because it always changes bits. Use
4715 <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]4716
4717<h5>Example:</h5>
4718<pre>
4719 %X = fpext float 3.1415 to double <i>; yields double:3.1415</i>
4720 %Y = fpext float 1.0 to float <i>; yields float:1.0 (no-op)</i>
4721</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4722
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4723</div>
4724
4725<!-- _______________________________________________________________________ -->
4726<div class="doc_subsubsection">
Reid Spencer2eadb532007-01-21 00:29:26 +0000[diff] [blame]4727 <a name="i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4728</div>
4729<div class="doc_text">
4730
4731<h5>Syntax:</h5>
4732<pre>
Reid Spencer753163d2007-07-31 14:40:14 +0000[diff] [blame]4733 &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]4734</pre>
4735
4736<h5>Overview:</h5>
Reid Spencer753163d2007-07-31 14:40:14 +0000[diff] [blame]4737<p>The '<tt>fptoui</tt>' converts a floating point <tt>value</tt> to its
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4738 unsigned integer equivalent of type <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4739
4740<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4741<p>The '<tt>fptoui</tt>' instruction takes a value to cast, which must be a
4742 scalar or vector <a href="#t_floating">floating point</a> value, and a type
4743 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
4744 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
4745 vector integer type with the same number of elements as <tt>ty</tt></p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4746
4747<h5>Semantics:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4748<p>The '<tt>fptoui</tt>' instruction converts its
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4749 <a href="#t_floating">floating point</a> operand into the nearest (rounding
4750 towards zero) unsigned integer value. If the value cannot fit
4751 in <tt>ty2</tt>, the results are undefined.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4752
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4753<h5>Example:</h5>
4754<pre>
Reid Spencer753163d2007-07-31 14:40:14 +0000[diff] [blame]4755 %X = fptoui double 123.0 to i32 <i>; yields i32:123</i>
Chris Lattner5b95a172007-09-22 03:17:52 +0000[diff] [blame]4756 %Y = fptoui float 1.0E+300 to i1 <i>; yields undefined:1</i>
Gabor Greiff50fd572009-10-28 09:21:30 +0000[diff] [blame]4757 %Z = fptoui float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4758</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4759
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4760</div>
4761
4762<!-- _______________________________________________________________________ -->
4763<div class="doc_subsubsection">
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]4764 <a name="i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4765</div>
4766<div class="doc_text">
4767
4768<h5>Syntax:</h5>
4769<pre>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]4770 &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]4771</pre>
4772
4773<h5>Overview:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4774<p>The '<tt>fptosi</tt>' instruction converts
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4775 <a href="#t_floating">floating point</a> <tt>value</tt> to
4776 type <tt>ty2</tt>.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]4777
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]4778<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4779<p>The '<tt>fptosi</tt>' instruction takes a value to cast, which must be a
4780 scalar or vector <a href="#t_floating">floating point</a> value, and a type
4781 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
4782 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
4783 vector integer type with the same number of elements as <tt>ty</tt></p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]4784
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]4785<h5>Semantics:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4786<p>The '<tt>fptosi</tt>' instruction converts its
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4787 <a href="#t_floating">floating point</a> operand into the nearest (rounding
4788 towards zero) signed integer value. If the value cannot fit in <tt>ty2</tt>,
4789 the results are undefined.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]4790
Chris Lattner70de6632001-07-09 00:26:23 +0000[diff] [blame]4791<h5>Example:</h5>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]4792<pre>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]4793 %X = fptosi double -123.0 to i32 <i>; yields i32:-123</i>
Chris Lattner5b95a172007-09-22 03:17:52 +0000[diff] [blame]4794 %Y = fptosi float 1.0E-247 to i1 <i>; yields undefined:1</i>
Gabor Greiff50fd572009-10-28 09:21:30 +0000[diff] [blame]4795 %Z = fptosi float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4796</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4797
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4798</div>
4799
4800<!-- _______________________________________________________________________ -->
4801<div class="doc_subsubsection">
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]4802 <a name="i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4803</div>
4804<div class="doc_text">
4805
4806<h5>Syntax:</h5>
4807<pre>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]4808 &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]4809</pre>
4810
4811<h5>Overview:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]4812<p>The '<tt>uitofp</tt>' instruction regards <tt>value</tt> as an unsigned
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4813 integer and converts that value to the <tt>ty2</tt> type.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4814
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4815<h5>Arguments:</h5>
Nate Begemand4d45c22007-11-17 03:58:34 +0000[diff] [blame]4816<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]4817 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
4818 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
4819 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
4820 floating point type with the same number of elements as <tt>ty</tt></p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4821
4822<h5>Semantics:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]4823<p>The '<tt>uitofp</tt>' instruction interprets its operand as an unsigned
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4824 integer quantity and converts it to the corresponding floating point
4825 value. If the value cannot fit in the floating point value, the results are
4826 undefined.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4827
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4828<h5>Example:</h5>
4829<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4830 %X = uitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]4831 %Y = uitofp i8 -1 to double <i>; yields double:255.0</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4832</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4833
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4834</div>
4835
4836<!-- _______________________________________________________________________ -->
4837<div class="doc_subsubsection">
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]4838 <a name="i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4839</div>
4840<div class="doc_text">
4841
4842<h5>Syntax:</h5>
4843<pre>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]4844 &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]4845</pre>
4846
4847<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4848<p>The '<tt>sitofp</tt>' instruction regards <tt>value</tt> as a signed integer
4849 and converts that value to the <tt>ty2</tt> type.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4850
4851<h5>Arguments:</h5>
Nate Begemand4d45c22007-11-17 03:58:34 +0000[diff] [blame]4852<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]4853 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
4854 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
4855 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
4856 floating point type with the same number of elements as <tt>ty</tt></p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4857
4858<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4859<p>The '<tt>sitofp</tt>' instruction interprets its operand as a signed integer
4860 quantity and converts it to the corresponding floating point value. If the
4861 value cannot fit in the floating point value, the results are undefined.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4862
4863<h5>Example:</h5>
4864<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4865 %X = sitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]4866 %Y = sitofp i8 -1 to double <i>; yields double:-1.0</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4867</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4868
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4869</div>
4870
4871<!-- _______________________________________________________________________ -->
4872<div class="doc_subsubsection">
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]4873 <a name="i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a>
4874</div>
4875<div class="doc_text">
4876
4877<h5>Syntax:</h5>
4878<pre>
4879 &lt;result&gt; = ptrtoint &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4880</pre>
4881
4882<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4883<p>The '<tt>ptrtoint</tt>' instruction converts the pointer <tt>value</tt> to
4884 the integer type <tt>ty2</tt>.</p>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]4885
4886<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4887<p>The '<tt>ptrtoint</tt>' instruction takes a <tt>value</tt> to cast, which
4888 must be a <a href="#t_pointer">pointer</a> value, and a type to cast it to
4889 <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]4890
4891<h5>Semantics:</h5>
4892<p>The '<tt>ptrtoint</tt>' instruction converts <tt>value</tt> to integer type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4893 <tt>ty2</tt> by interpreting the pointer value as an integer and either
4894 truncating or zero extending that value to the size of the integer type. If
4895 <tt>value</tt> is smaller than <tt>ty2</tt> then a zero extension is done. If
4896 <tt>value</tt> is larger than <tt>ty2</tt> then a truncation is done. If they
4897 are the same size, then nothing is done (<i>no-op cast</i>) other than a type
4898 change.</p>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]4899
4900<h5>Example:</h5>
4901<pre>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]4902 %X = ptrtoint i32* %X to i8 <i>; yields truncation on 32-bit architecture</i>
4903 %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]4904</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4905
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]4906</div>
4907
4908<!-- _______________________________________________________________________ -->
4909<div class="doc_subsubsection">
4910 <a name="i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a>
4911</div>
4912<div class="doc_text">
4913
4914<h5>Syntax:</h5>
4915<pre>
4916 &lt;result&gt; = inttoptr &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4917</pre>
4918
4919<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4920<p>The '<tt>inttoptr</tt>' instruction converts an integer <tt>value</tt> to a
4921 pointer type, <tt>ty2</tt>.</p>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]4922
4923<h5>Arguments:</h5>
Duncan Sands16f122e2007-03-30 12:22:09 +0000[diff] [blame]4924<p>The '<tt>inttoptr</tt>' instruction takes an <a href="#t_integer">integer</a>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4925 value to cast, and a type to cast it to, which must be a
4926 <a href="#t_pointer">pointer</a> type.</p>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]4927
4928<h5>Semantics:</h5>
4929<p>The '<tt>inttoptr</tt>' instruction converts <tt>value</tt> to type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4930 <tt>ty2</tt> by applying either a zero extension or a truncation depending on
4931 the size of the integer <tt>value</tt>. If <tt>value</tt> is larger than the
4932 size of a pointer then a truncation is done. If <tt>value</tt> is smaller
4933 than the size of a pointer then a zero extension is done. If they are the
4934 same size, nothing is done (<i>no-op cast</i>).</p>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]4935
4936<h5>Example:</h5>
4937<pre>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]4938 %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]4939 %Y = inttoptr i32 255 to i32* <i>; yields no-op on 32-bit architecture</i>
4940 %Z = inttoptr i64 0 to i32* <i>; yields truncation on 32-bit architecture</i>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]4941</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4942
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]4943</div>
4944
4945<!-- _______________________________________________________________________ -->
4946<div class="doc_subsubsection">
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]4947 <a name="i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4948</div>
4949<div class="doc_text">
4950
4951<h5>Syntax:</h5>
4952<pre>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]4953 &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]4954</pre>
4955
4956<h5>Overview:</h5>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]4957<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4958 <tt>ty2</tt> without changing any bits.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4959
4960<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4961<p>The '<tt>bitcast</tt>' instruction takes a value to cast, which must be a
4962 non-aggregate first class value, and a type to cast it to, which must also be
4963 a non-aggregate <a href="#t_firstclass">first class</a> type. The bit sizes
4964 of <tt>value</tt> and the destination type, <tt>ty2</tt>, must be
4965 identical. If the source type is a pointer, the destination type must also be
4966 a pointer. This instruction supports bitwise conversion of vectors to
4967 integers and to vectors of other types (as long as they have the same
4968 size).</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4969
4970<h5>Semantics:</h5>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]4971<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4972 <tt>ty2</tt>. It is always a <i>no-op cast</i> because no bits change with
4973 this conversion. The conversion is done as if the <tt>value</tt> had been
4974 stored to memory and read back as type <tt>ty2</tt>. Pointer types may only
4975 be converted to other pointer types with this instruction. To convert
4976 pointers to other types, use the <a href="#i_inttoptr">inttoptr</a> or
4977 <a href="#i_ptrtoint">ptrtoint</a> instructions first.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4978
4979<h5>Example:</h5>
4980<pre>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]4981 %X = bitcast i8 255 to i8 <i>; yields i8 :-1</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4982 %Y = bitcast i32* %x to sint* <i>; yields sint*:%x</i>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4983 %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]4984</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4985
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4986</div>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]4987
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]4988<!-- ======================================================================= -->
4989<div class="doc_subsection"> <a name="otherops">Other Operations</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4990
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]4991<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4992
4993<p>The instructions in this category are the "miscellaneous" instructions, which
4994 defy better classification.</p>
4995
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]4996</div>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4997
4998<!-- _______________________________________________________________________ -->
4999<div class="doc_subsubsection"><a name="i_icmp">'<tt>icmp</tt>' Instruction</a>
5000</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5001
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5002<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5003
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5004<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5005<pre>
5006 &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]5007</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5008
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5009<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5010<p>The '<tt>icmp</tt>' instruction returns a boolean value or a vector of
5011 boolean values based on comparison of its two integer, integer vector, or
5012 pointer operands.</p>
5013
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5014<h5>Arguments:</h5>
5015<p>The '<tt>icmp</tt>' instruction takes three operands. The first operand is
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5016 the condition code indicating the kind of comparison to perform. It is not a
5017 value, just a keyword. The possible condition code are:</p>
5018
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5019<ol>
5020 <li><tt>eq</tt>: equal</li>
5021 <li><tt>ne</tt>: not equal </li>
5022 <li><tt>ugt</tt>: unsigned greater than</li>
5023 <li><tt>uge</tt>: unsigned greater or equal</li>
5024 <li><tt>ult</tt>: unsigned less than</li>
5025 <li><tt>ule</tt>: unsigned less or equal</li>
5026 <li><tt>sgt</tt>: signed greater than</li>
5027 <li><tt>sge</tt>: signed greater or equal</li>
5028 <li><tt>slt</tt>: signed less than</li>
5029 <li><tt>sle</tt>: signed less or equal</li>
5030</ol>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5031
Chris Lattnerc0f423a2007-01-15 01:54:13 +0000[diff] [blame]5032<p>The remaining two arguments must be <a href="#t_integer">integer</a> or
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5033 <a href="#t_pointer">pointer</a> or integer <a href="#t_vector">vector</a>
5034 typed. They must also be identical types.</p>
5035
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5036<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5037<p>The '<tt>icmp</tt>' compares <tt>op1</tt> and <tt>op2</tt> according to the
5038 condition code given as <tt>cond</tt>. The comparison performed always yields
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]5039 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]5040 result, as follows:</p>
5041
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5042<ol>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5043 <li><tt>eq</tt>: yields <tt>true</tt> if the operands are equal,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5044 <tt>false</tt> otherwise. No sign interpretation is necessary or
5045 performed.</li>
5046
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5047 <li><tt>ne</tt>: yields <tt>true</tt> if the operands are unequal,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5048 <tt>false</tt> otherwise. No sign interpretation is necessary or
5049 performed.</li>
5050
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5051 <li><tt>ugt</tt>: interprets the operands as unsigned values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5052 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
5053
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5054 <li><tt>uge</tt>: interprets the operands as unsigned values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5055 <tt>true</tt> if <tt>op1</tt> is greater than or equal
5056 to <tt>op2</tt>.</li>
5057
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5058 <li><tt>ult</tt>: interprets the operands as unsigned values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5059 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
5060
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5061 <li><tt>ule</tt>: interprets the operands as unsigned values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5062 <tt>true</tt> if <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
5063
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5064 <li><tt>sgt</tt>: interprets the operands as signed values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5065 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
5066
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5067 <li><tt>sge</tt>: interprets the operands as signed values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5068 <tt>true</tt> if <tt>op1</tt> is greater than or equal
5069 to <tt>op2</tt>.</li>
5070
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5071 <li><tt>slt</tt>: interprets the operands as signed values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5072 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
5073
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5074 <li><tt>sle</tt>: interprets the operands as signed values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5075 <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]5076</ol>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5077
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5078<p>If the operands are <a href="#t_pointer">pointer</a> typed, the pointer
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5079 values are compared as if they were integers.</p>
5080
5081<p>If the operands are integer vectors, then they are compared element by
5082 element. The result is an <tt>i1</tt> vector with the same number of elements
5083 as the values being compared. Otherwise, the result is an <tt>i1</tt>.</p>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5084
5085<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5086<pre>
5087 &lt;result&gt; = icmp eq i32 4, 5 <i>; yields: result=false</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]5088 &lt;result&gt; = icmp ne float* %X, %X <i>; yields: result=false</i>
5089 &lt;result&gt; = icmp ult i16 4, 5 <i>; yields: result=true</i>
5090 &lt;result&gt; = icmp sgt i16 4, 5 <i>; yields: result=false</i>
5091 &lt;result&gt; = icmp ule i16 -4, 5 <i>; yields: result=false</i>
5092 &lt;result&gt; = icmp sge i16 4, 5 <i>; yields: result=false</i>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5093</pre>
Dan Gohmana5127ab2009-01-22 01:39:38 +0000[diff] [blame]5094
5095<p>Note that the code generator does not yet support vector types with
5096 the <tt>icmp</tt> instruction.</p>
5097
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5098</div>
5099
5100<!-- _______________________________________________________________________ -->
5101<div class="doc_subsubsection"><a name="i_fcmp">'<tt>fcmp</tt>' Instruction</a>
5102</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5103
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5104<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5105
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5106<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5107<pre>
5108 &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]5109</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5110
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5111<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5112<p>The '<tt>fcmp</tt>' instruction returns a boolean value or vector of boolean
5113 values based on comparison of its operands.</p>
5114
5115<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]5116(<a href="#t_integer"><tt>i1</tt></a>).</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5117
5118<p>If the operands are floating point vectors, then the result type is a vector
5119 of boolean with the same number of elements as the operands being
5120 compared.</p>
5121
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5122<h5>Arguments:</h5>
5123<p>The '<tt>fcmp</tt>' instruction takes three operands. The first operand is
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5124 the condition code indicating the kind of comparison to perform. It is not a
5125 value, just a keyword. The possible condition code are:</p>
5126
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5127<ol>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]5128 <li><tt>false</tt>: no comparison, always returns false</li>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5129 <li><tt>oeq</tt>: ordered and equal</li>
5130 <li><tt>ogt</tt>: ordered and greater than </li>
5131 <li><tt>oge</tt>: ordered and greater than or equal</li>
5132 <li><tt>olt</tt>: ordered and less than </li>
5133 <li><tt>ole</tt>: ordered and less than or equal</li>
5134 <li><tt>one</tt>: ordered and not equal</li>
5135 <li><tt>ord</tt>: ordered (no nans)</li>
5136 <li><tt>ueq</tt>: unordered or equal</li>
5137 <li><tt>ugt</tt>: unordered or greater than </li>
5138 <li><tt>uge</tt>: unordered or greater than or equal</li>
5139 <li><tt>ult</tt>: unordered or less than </li>
5140 <li><tt>ule</tt>: unordered or less than or equal</li>
5141 <li><tt>une</tt>: unordered or not equal</li>
5142 <li><tt>uno</tt>: unordered (either nans)</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]5143 <li><tt>true</tt>: no comparison, always returns true</li>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5144</ol>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5145
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5146<p><i>Ordered</i> means that neither operand is a QNAN while
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5147 <i>unordered</i> means that either operand may be a QNAN.</p>
5148
5149<p>Each of <tt>val1</tt> and <tt>val2</tt> arguments must be either
5150 a <a href="#t_floating">floating point</a> type or
5151 a <a href="#t_vector">vector</a> of floating point type. They must have
5152 identical types.</p>
5153
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5154<h5>Semantics:</h5>
Gabor Greif0f75ad02008-08-07 21:46:00 +0000[diff] [blame]5155<p>The '<tt>fcmp</tt>' instruction compares <tt>op1</tt> and <tt>op2</tt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5156 according to the condition code given as <tt>cond</tt>. If the operands are
5157 vectors, then the vectors are compared element by element. Each comparison
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]5158 performed always yields an <a href="#t_integer">i1</a> result, as
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5159 follows:</p>
5160
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5161<ol>
5162 <li><tt>false</tt>: always yields <tt>false</tt>, regardless of operands.</li>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5163
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5164 <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]5165 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
5166
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]5167 <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]5168 <tt>op1</tt> is greater than <tt>op2</tt>.</li>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5169
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5170 <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]5171 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
5172
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5173 <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]5174 <tt>op1</tt> is less than <tt>op2</tt>.</li>
5175
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5176 <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]5177 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
5178
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5179 <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]5180 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
5181
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]5182 <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]5183
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5184 <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]5185 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
5186
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5187 <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]5188 <tt>op1</tt> is greater than <tt>op2</tt>.</li>
5189
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5190 <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]5191 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
5192
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5193 <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]5194 <tt>op1</tt> is less than <tt>op2</tt>.</li>
5195
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5196 <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]5197 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
5198
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5199 <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]5200 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
5201
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]5202 <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]5203
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5204 <li><tt>true</tt>: always yields <tt>true</tt>, regardless of operands.</li>
5205</ol>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5206
5207<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5208<pre>
5209 &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]5210 &lt;result&gt; = fcmp one float 4.0, 5.0 <i>; yields: result=true</i>
5211 &lt;result&gt; = fcmp olt float 4.0, 5.0 <i>; yields: result=true</i>
5212 &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]5213</pre>
Dan Gohmana5127ab2009-01-22 01:39:38 +0000[diff] [blame]5214
5215<p>Note that the code generator does not yet support vector types with
5216 the <tt>fcmp</tt> instruction.</p>
5217
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5218</div>
5219
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5220<!-- _______________________________________________________________________ -->
Nate Begemand2195702008-05-12 19:01:56 +0000[diff] [blame]5221<div class="doc_subsubsection">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]5222 <a name="i_phi">'<tt>phi</tt>' Instruction</a>
5223</div>
5224
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5225<div class="doc_text">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]5226
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5227<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5228<pre>
5229 &lt;result&gt; = phi &lt;ty&gt; [ &lt;val0&gt;, &lt;label0&gt;], ...
5230</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]5231
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5232<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5233<p>The '<tt>phi</tt>' instruction is used to implement the &#966; node in the
5234 SSA graph representing the function.</p>
5235
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5236<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5237<p>The type of the incoming values is specified with the first type field. After
5238 this, the '<tt>phi</tt>' instruction takes a list of pairs as arguments, with
5239 one pair for each predecessor basic block of the current block. Only values
5240 of <a href="#t_firstclass">first class</a> type may be used as the value
5241 arguments to the PHI node. Only labels may be used as the label
5242 arguments.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]5243
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5244<p>There must be no non-phi instructions between the start of a basic block and
5245 the PHI instructions: i.e. PHI instructions must be first in a basic
5246 block.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]5247
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5248<p>For the purposes of the SSA form, the use of each incoming value is deemed to
5249 occur on the edge from the corresponding predecessor block to the current
5250 block (but after any definition of an '<tt>invoke</tt>' instruction's return
5251 value on the same edge).</p>
Jay Foad1a4eea52009-06-03 10:20:10 +0000[diff] [blame]5252
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5253<h5>Semantics:</h5>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5254<p>At runtime, the '<tt>phi</tt>' instruction logically takes on the value
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5255 specified by the pair corresponding to the predecessor basic block that
5256 executed just prior to the current block.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]5257
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5258<h5>Example:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]5259<pre>
5260Loop: ; Infinite loop that counts from 0 on up...
5261 %indvar = phi i32 [ 0, %LoopHeader ], [ %nextindvar, %Loop ]
5262 %nextindvar = add i32 %indvar, 1
5263 br label %Loop
5264</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5265
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5266</div>
5267
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5268<!-- _______________________________________________________________________ -->
5269<div class="doc_subsubsection">
5270 <a name="i_select">'<tt>select</tt>' Instruction</a>
5271</div>
5272
5273<div class="doc_text">
5274
5275<h5>Syntax:</h5>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5276<pre>
Dan Gohmanc579d972008-09-09 01:02:47 +0000[diff] [blame]5277 &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>
5278
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]5279 <i>selty</i> is either i1 or {&lt;N x i1&gt;}
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5280</pre>
5281
5282<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5283<p>The '<tt>select</tt>' instruction is used to choose one value based on a
5284 condition, without branching.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5285
5286
5287<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5288<p>The '<tt>select</tt>' instruction requires an 'i1' value or a vector of 'i1'
5289 values indicating the condition, and two values of the
5290 same <a href="#t_firstclass">first class</a> type. If the val1/val2 are
5291 vectors and the condition is a scalar, then entire vectors are selected, not
5292 individual elements.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5293
5294<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5295<p>If the condition is an i1 and it evaluates to 1, the instruction returns the
5296 first value argument; otherwise, it returns the second value argument.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5297
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5298<p>If the condition is a vector of i1, then the value arguments must be vectors
5299 of the same size, and the selection is done element by element.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5300
5301<h5>Example:</h5>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5302<pre>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]5303 %X = select i1 true, i8 17, i8 42 <i>; yields i8:17</i>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5304</pre>
Dan Gohmana5127ab2009-01-22 01:39:38 +0000[diff] [blame]5305
5306<p>Note that the code generator does not yet support conditions
5307 with vector type.</p>
5308
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5309</div>
5310
Robert Bocchinof72fdfe2006-01-15 20:48:27 +0000[diff] [blame]5311<!-- _______________________________________________________________________ -->
5312<div class="doc_subsubsection">
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5313 <a name="i_call">'<tt>call</tt>' Instruction</a>
5314</div>
5315
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5316<div class="doc_text">
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5317
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]5318<h5>Syntax:</h5>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5319<pre>
Devang Patel02256232008-10-07 17:48:33 +0000[diff] [blame]5320 &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]5321</pre>
5322
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]5323<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5324<p>The '<tt>call</tt>' instruction represents a simple function call.</p>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5325
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]5326<h5>Arguments:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5327<p>This instruction requires several arguments:</p>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5328
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]5329<ol>
Jeffrey Yasskinb8677462010-01-09 19:44:16 +0000[diff] [blame]5330 <li>The optional "tail" marker indicates that the callee function does not
5331 access any allocas or varargs in the caller. Note that calls may be
5332 marked "tail" even if they do not occur before
5333 a <a href="#i_ret"><tt>ret</tt></a> instruction. If the "tail" marker is
5334 present, the function call is eligible for tail call optimization,
5335 but <a href="CodeGenerator.html#tailcallopt">might not in fact be
Evan Cheng59676492010-03-08 21:05:02 +0000[diff] [blame]5336 optimized into a jump</a>. The code generator may optimize calls marked
5337 "tail" with either 1) automatic <a href="CodeGenerator.html#sibcallopt">
5338 sibling call optimization</a> when the caller and callee have
5339 matching signatures, or 2) forced tail call optimization when the
5340 following extra requirements are met:
Jeffrey Yasskinb8677462010-01-09 19:44:16 +0000[diff] [blame]5341 <ul>
5342 <li>Caller and callee both have the calling
5343 convention <tt>fastcc</tt>.</li>
5344 <li>The call is in tail position (ret immediately follows call and ret
5345 uses value of call or is void).</li>
5346 <li>Option <tt>-tailcallopt</tt> is enabled,
Dan Gohman6232f732010-03-02 01:08:11 +0000[diff] [blame]5347 or <code>llvm::GuaranteedTailCallOpt</code> is <code>true</code>.</li>
Jeffrey Yasskinb8677462010-01-09 19:44:16 +0000[diff] [blame]5348 <li><a href="CodeGenerator.html#tailcallopt">Platform specific
5349 constraints are met.</a></li>
5350 </ul>
5351 </li>
Devang Patel7e9b05e2008-10-06 18:50:38 +0000[diff] [blame]5352
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5353 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
5354 convention</a> the call should use. If none is specified, the call
Jeffrey Yasskinb8677462010-01-09 19:44:16 +0000[diff] [blame]5355 defaults to using C calling conventions. The calling convention of the
5356 call must match the calling convention of the target function, or else the
5357 behavior is undefined.</li>
Devang Patel7e9b05e2008-10-06 18:50:38 +0000[diff] [blame]5358
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5359 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
5360 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
5361 '<tt>inreg</tt>' attributes are valid here.</li>
5362
5363 <li>'<tt>ty</tt>': the type of the call instruction itself which is also the
5364 type of the return value. Functions that return no value are marked
5365 <tt><a href="#t_void">void</a></tt>.</li>
5366
5367 <li>'<tt>fnty</tt>': shall be the signature of the pointer to function value
5368 being invoked. The argument types must match the types implied by this
5369 signature. This type can be omitted if the function is not varargs and if
5370 the function type does not return a pointer to a function.</li>
5371
5372 <li>'<tt>fnptrval</tt>': An LLVM value containing a pointer to a function to
5373 be invoked. In most cases, this is a direct function invocation, but
5374 indirect <tt>call</tt>s are just as possible, calling an arbitrary pointer
5375 to function value.</li>
5376
5377 <li>'<tt>function args</tt>': argument list whose types match the function
Chris Lattner47f2a832010-03-02 06:36:51 +0000[diff] [blame]5378 signature argument types and parameter attributes. All arguments must be
5379 of <a href="#t_firstclass">first class</a> type. If the function
5380 signature indicates the function accepts a variable number of arguments,
5381 the extra arguments can be specified.</li>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5382
5383 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
5384 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
5385 '<tt>readnone</tt>' attributes are valid here.</li>
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]5386</ol>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5387
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]5388<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5389<p>The '<tt>call</tt>' instruction is used to cause control flow to transfer to
5390 a specified function, with its incoming arguments bound to the specified
5391 values. Upon a '<tt><a href="#i_ret">ret</a></tt>' instruction in the called
5392 function, control flow continues with the instruction after the function
5393 call, and the return value of the function is bound to the result
5394 argument.</p>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5395
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]5396<h5>Example:</h5>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5397<pre>
Nick Lewyckya9b13d52007-09-08 13:57:50 +0000[diff] [blame]5398 %retval = call i32 @test(i32 %argc)
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]5399 call i32 (i8*, ...)* @printf(i8* %msg, i32 12, i8 42) <i>; yields i32</i>
Chris Lattnerfb7c88d2008-03-21 17:24:17 +0000[diff] [blame]5400 %X = tail call i32 @foo() <i>; yields i32</i>
5401 %Y = tail call <a href="#callingconv">fastcc</a> i32 @foo() <i>; yields i32</i>
5402 call void %foo(i8 97 signext)
Devang Pateld6cff512008-03-10 20:49:15 +0000[diff] [blame]5403
5404 %struct.A = type { i32, i8 }
Devang Patel7e9b05e2008-10-06 18:50:38 +0000[diff] [blame]5405 %r = call %struct.A @foo() <i>; yields { 32, i8 }</i>
Dan Gohmancc3132e2008-10-04 19:00:07 +0000[diff] [blame]5406 %gr = extractvalue %struct.A %r, 0 <i>; yields i32</i>
5407 %gr1 = extractvalue %struct.A %r, 1 <i>; yields i8</i>
Chris Lattner6cbe8e92008-10-08 06:26:11 +0000[diff] [blame]5408 %Z = call void @foo() noreturn <i>; indicates that %foo never returns normally</i>
Matthijs Kooijmaneefa7df2008-10-07 10:03:45 +0000[diff] [blame]5409 %ZZ = call zeroext i32 @bar() <i>; Return value is %zero extended</i>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5410</pre>
5411
Dale Johannesen68f971b2009-09-24 18:38:21 +0000[diff] [blame]5412<p>llvm treats calls to some functions with names and arguments that match the
Dale Johannesen722212d2009-09-25 17:04:42 +0000[diff] [blame]5413standard C99 library as being the C99 library functions, and may perform
5414optimizations or generate code for them under that assumption. This is
5415something we'd like to change in the future to provide better support for
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]5416freestanding environments and non-C-based languages.</p>
Dale Johannesen68f971b2009-09-24 18:38:21 +0000[diff] [blame]5417
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5418</div>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5419
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5420<!-- _______________________________________________________________________ -->
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5421<div class="doc_subsubsection">
Chris Lattner33337472006-01-13 23:26:01 +0000[diff] [blame]5422 <a name="i_va_arg">'<tt>va_arg</tt>' Instruction</a>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5423</div>
5424
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5425<div class="doc_text">
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5426
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]5427<h5>Syntax:</h5>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5428<pre>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]5429 &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]5430</pre>
5431
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]5432<h5>Overview:</h5>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]5433<p>The '<tt>va_arg</tt>' instruction is used to access arguments passed through
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5434 the "variable argument" area of a function call. It is used to implement the
5435 <tt>va_arg</tt> macro in C.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5436
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]5437<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5438<p>This instruction takes a <tt>va_list*</tt> value and the type of the
5439 argument. It returns a value of the specified argument type and increments
5440 the <tt>va_list</tt> to point to the next argument. The actual type
5441 of <tt>va_list</tt> is target specific.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5442
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]5443<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5444<p>The '<tt>va_arg</tt>' instruction loads an argument of the specified type
5445 from the specified <tt>va_list</tt> and causes the <tt>va_list</tt> to point
5446 to the next argument. For more information, see the variable argument
5447 handling <a href="#int_varargs">Intrinsic Functions</a>.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5448
5449<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]5450 take a variable number of arguments, for example, the <tt>vfprintf</tt>
5451 function.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5452
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5453<p><tt>va_arg</tt> is an LLVM instruction instead of
5454 an <a href="#intrinsics">intrinsic function</a> because it takes a type as an
5455 argument.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5456
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]5457<h5>Example:</h5>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5458<p>See the <a href="#int_varargs">variable argument processing</a> section.</p>
5459
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5460<p>Note that the code generator does not yet fully support va_arg on many
5461 targets. Also, it does not currently support va_arg with aggregate types on
5462 any target.</p>
Dan Gohman3065b612009-01-12 23:12:39 +0000[diff] [blame]5463
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5464</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5465
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5466<!-- *********************************************************************** -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]5467<div class="doc_section"> <a name="intrinsics">Intrinsic Functions</a> </div>
5468<!-- *********************************************************************** -->
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5469
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5470<div class="doc_text">
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5471
5472<p>LLVM supports the notion of an "intrinsic function". These functions have
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5473 well known names and semantics and are required to follow certain
5474 restrictions. Overall, these intrinsics represent an extension mechanism for
5475 the LLVM language that does not require changing all of the transformations
5476 in LLVM when adding to the language (or the bitcode reader/writer, the
5477 parser, etc...).</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5478
John Criswell88190562005-05-16 16:17:45 +0000[diff] [blame]5479<p>Intrinsic function names must all start with an "<tt>llvm.</tt>" prefix. This
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5480 prefix is reserved in LLVM for intrinsic names; thus, function names may not
5481 begin with this prefix. Intrinsic functions must always be external
5482 functions: you cannot define the body of intrinsic functions. Intrinsic
5483 functions may only be used in call or invoke instructions: it is illegal to
5484 take the address of an intrinsic function. Additionally, because intrinsic
5485 functions are part of the LLVM language, it is required if any are added that
5486 they be documented here.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5487
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5488<p>Some intrinsic functions can be overloaded, i.e., the intrinsic represents a
5489 family of functions that perform the same operation but on different data
5490 types. Because LLVM can represent over 8 million different integer types,
5491 overloading is used commonly to allow an intrinsic function to operate on any
5492 integer type. One or more of the argument types or the result type can be
5493 overloaded to accept any integer type. Argument types may also be defined as
5494 exactly matching a previous argument's type or the result type. This allows
5495 an intrinsic function which accepts multiple arguments, but needs all of them
5496 to be of the same type, to only be overloaded with respect to a single
5497 argument or the result.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5498
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5499<p>Overloaded intrinsics will have the names of its overloaded argument types
5500 encoded into its function name, each preceded by a period. Only those types
5501 which are overloaded result in a name suffix. Arguments whose type is matched
5502 against another type do not. For example, the <tt>llvm.ctpop</tt> function
5503 can take an integer of any width and returns an integer of exactly the same
5504 integer width. This leads to a family of functions such as
5505 <tt>i8 @llvm.ctpop.i8(i8 %val)</tt> and <tt>i29 @llvm.ctpop.i29(i29
5506 %val)</tt>. Only one type, the return type, is overloaded, and only one type
5507 suffix is required. Because the argument's type is matched against the return
5508 type, it does not require its own name suffix.</p>
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]5509
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5510<p>To learn how to add an intrinsic function, please see the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5511 <a href="ExtendingLLVM.html">Extending LLVM Guide</a>.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5512
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5513</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5514
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5515<!-- ======================================================================= -->
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5516<div class="doc_subsection">
5517 <a name="int_varargs">Variable Argument Handling Intrinsics</a>
5518</div>
5519
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5520<div class="doc_text">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5521
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5522<p>Variable argument support is defined in LLVM with
5523 the <a href="#i_va_arg"><tt>va_arg</tt></a> instruction and these three
5524 intrinsic functions. These functions are related to the similarly named
5525 macros defined in the <tt>&lt;stdarg.h&gt;</tt> header file.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5526
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5527<p>All of these functions operate on arguments that use a target-specific value
5528 type "<tt>va_list</tt>". The LLVM assembly language reference manual does
5529 not define what this type is, so all transformations should be prepared to
5530 handle these functions regardless of the type used.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5531
Chris Lattner30b868d2006-05-15 17:26:46 +0000[diff] [blame]5532<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]5533 instruction and the variable argument handling intrinsic functions are
5534 used.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5535
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]5536<pre class="doc_code">
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]5537define i32 @test(i32 %X, ...) {
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5538 ; Initialize variable argument processing
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5539 %ap = alloca i8*
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]5540 %ap2 = bitcast i8** %ap to i8*
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]5541 call void @llvm.va_start(i8* %ap2)
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5542
5543 ; Read a single integer argument
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5544 %tmp = va_arg i8** %ap, i32
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5545
5546 ; Demonstrate usage of llvm.va_copy and llvm.va_end
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5547 %aq = alloca i8*
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]5548 %aq2 = bitcast i8** %aq to i8*
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5549 call void @llvm.va_copy(i8* %aq2, i8* %ap2)
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]5550 call void @llvm.va_end(i8* %aq2)
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5551
5552 ; Stop processing of arguments.
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]5553 call void @llvm.va_end(i8* %ap2)
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]5554 ret i32 %tmp
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5555}
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]5556
5557declare void @llvm.va_start(i8*)
5558declare void @llvm.va_copy(i8*, i8*)
5559declare void @llvm.va_end(i8*)
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5560</pre>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5561
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]5562</div>
5563
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5564<!-- _______________________________________________________________________ -->
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5565<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5566 <a name="int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5567</div>
5568
5569
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5570<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5571
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5572<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5573<pre>
5574 declare void %llvm.va_start(i8* &lt;arglist&gt;)
5575</pre>
5576
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5577<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5578<p>The '<tt>llvm.va_start</tt>' intrinsic initializes <tt>*&lt;arglist&gt;</tt>
5579 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]5580
5581<h5>Arguments:</h5>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]5582<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]5583
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5584<h5>Semantics:</h5>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]5585<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]5586 macro available in C. In a target-dependent way, it initializes
5587 the <tt>va_list</tt> element to which the argument points, so that the next
5588 call to <tt>va_arg</tt> will produce the first variable argument passed to
5589 the function. Unlike the C <tt>va_start</tt> macro, this intrinsic does not
5590 need to know the last argument of the function as the compiler can figure
5591 that out.</p>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]5592
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5593</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5594
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5595<!-- _______________________________________________________________________ -->
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5596<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5597 <a name="int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5598</div>
5599
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5600<div class="doc_text">
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]5601
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5602<h5>Syntax:</h5>
5603<pre>
5604 declare void @llvm.va_end(i8* &lt;arglist&gt;)
5605</pre>
5606
5607<h5>Overview:</h5>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5608<p>The '<tt>llvm.va_end</tt>' intrinsic destroys <tt>*&lt;arglist&gt;</tt>,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5609 which has been initialized previously
5610 with <tt><a href="#int_va_start">llvm.va_start</a></tt>
5611 or <tt><a href="#i_va_copy">llvm.va_copy</a></tt>.</p>
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]5612
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5613<h5>Arguments:</h5>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5614<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]5615
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5616<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5617<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]5618 macro available in C. In a target-dependent way, it destroys
5619 the <tt>va_list</tt> element to which the argument points. Calls
5620 to <a href="#int_va_start"><tt>llvm.va_start</tt></a>
5621 and <a href="#int_va_copy"> <tt>llvm.va_copy</tt></a> must be matched exactly
5622 with calls to <tt>llvm.va_end</tt>.</p>
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]5623
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5624</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5625
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5626<!-- _______________________________________________________________________ -->
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5627<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5628 <a name="int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5629</div>
5630
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5631<div class="doc_text">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5632
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5633<h5>Syntax:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5634<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]5635 declare void @llvm.va_copy(i8* &lt;destarglist&gt;, i8* &lt;srcarglist&gt;)
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5636</pre>
5637
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5638<h5>Overview:</h5>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5639<p>The '<tt>llvm.va_copy</tt>' intrinsic copies the current argument position
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5640 from the source argument list to the destination argument list.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5641
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5642<h5>Arguments:</h5>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]5643<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]5644 The second argument is a pointer to a <tt>va_list</tt> element to copy
5645 from.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5646
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5647<h5>Semantics:</h5>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5648<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]5649 macro available in C. In a target-dependent way, it copies the
5650 source <tt>va_list</tt> element into the destination <tt>va_list</tt>
5651 element. This intrinsic is necessary because
5652 the <tt><a href="#int_va_start"> llvm.va_start</a></tt> intrinsic may be
5653 arbitrarily complex and require, for example, memory allocation.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5654
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5655</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5656
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5657<!-- ======================================================================= -->
5658<div class="doc_subsection">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5659 <a name="int_gc">Accurate Garbage Collection Intrinsics</a>
5660</div>
5661
5662<div class="doc_text">
5663
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5664<p>LLVM support for <a href="GarbageCollection.html">Accurate Garbage
Chris Lattner67c37d12008-08-05 18:29:16 +0000[diff] [blame]5665Collection</a> (GC) requires the implementation and generation of these
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5666intrinsics. These intrinsics allow identification of <a href="#int_gcroot">GC
5667roots on the stack</a>, as well as garbage collector implementations that
5668require <a href="#int_gcread">read</a> and <a href="#int_gcwrite">write</a>
5669barriers. Front-ends for type-safe garbage collected languages should generate
5670these intrinsics to make use of the LLVM garbage collectors. For more details,
5671see <a href="GarbageCollection.html">Accurate Garbage Collection with
5672LLVM</a>.</p>
Christopher Lamb55c6d4f2007-12-17 01:00:21 +0000[diff] [blame]5673
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5674<p>The garbage collection intrinsics only operate on objects in the generic
5675 address space (address space zero).</p>
Christopher Lamb55c6d4f2007-12-17 01:00:21 +0000[diff] [blame]5676
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5677</div>
5678
5679<!-- _______________________________________________________________________ -->
5680<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5681 <a name="int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5682</div>
5683
5684<div class="doc_text">
5685
5686<h5>Syntax:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5687<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]5688 declare void @llvm.gcroot(i8** %ptrloc, i8* %metadata)
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5689</pre>
5690
5691<h5>Overview:</h5>
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]5692<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]5693 the code generator, and allows some metadata to be associated with it.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5694
5695<h5>Arguments:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5696<p>The first argument specifies the address of a stack object that contains the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5697 root pointer. The second pointer (which must be either a constant or a
5698 global value address) contains the meta-data to be associated with the
5699 root.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5700
5701<h5>Semantics:</h5>
Chris Lattner851b7712008-04-24 05:59:56 +0000[diff] [blame]5702<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]5703 location. At compile-time, the code generator generates information to allow
5704 the runtime to find the pointer at GC safe points. The '<tt>llvm.gcroot</tt>'
5705 intrinsic may only be used in a function which <a href="#gc">specifies a GC
5706 algorithm</a>.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5707
5708</div>
5709
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5710<!-- _______________________________________________________________________ -->
5711<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5712 <a name="int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5713</div>
5714
5715<div class="doc_text">
5716
5717<h5>Syntax:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5718<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]5719 declare i8* @llvm.gcread(i8* %ObjPtr, i8** %Ptr)
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5720</pre>
5721
5722<h5>Overview:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5723<p>The '<tt>llvm.gcread</tt>' intrinsic identifies reads of references from heap
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5724 locations, allowing garbage collector implementations that require read
5725 barriers.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5726
5727<h5>Arguments:</h5>
Chris Lattnerf9228072006-03-14 20:02:51 +0000[diff] [blame]5728<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]5729 allocated from the garbage collector. The first object is a pointer to the
5730 start of the referenced object, if needed by the language runtime (otherwise
5731 null).</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5732
5733<h5>Semantics:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5734<p>The '<tt>llvm.gcread</tt>' intrinsic has the same semantics as a load
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5735 instruction, but may be replaced with substantially more complex code by the
5736 garbage collector runtime, as needed. The '<tt>llvm.gcread</tt>' intrinsic
5737 may only be used in a function which <a href="#gc">specifies a GC
5738 algorithm</a>.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5739
5740</div>
5741
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5742<!-- _______________________________________________________________________ -->
5743<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5744 <a name="int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5745</div>
5746
5747<div class="doc_text">
5748
5749<h5>Syntax:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5750<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]5751 declare void @llvm.gcwrite(i8* %P1, i8* %Obj, i8** %P2)
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5752</pre>
5753
5754<h5>Overview:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5755<p>The '<tt>llvm.gcwrite</tt>' intrinsic identifies writes of references to heap
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5756 locations, allowing garbage collector implementations that require write
5757 barriers (such as generational or reference counting collectors).</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5758
5759<h5>Arguments:</h5>
Chris Lattnerf9228072006-03-14 20:02:51 +0000[diff] [blame]5760<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]5761 object to store it to, and the third is the address of the field of Obj to
5762 store to. If the runtime does not require a pointer to the object, Obj may
5763 be null.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5764
5765<h5>Semantics:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5766<p>The '<tt>llvm.gcwrite</tt>' intrinsic has the same semantics as a store
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5767 instruction, but may be replaced with substantially more complex code by the
5768 garbage collector runtime, as needed. The '<tt>llvm.gcwrite</tt>' intrinsic
5769 may only be used in a function which <a href="#gc">specifies a GC
5770 algorithm</a>.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5771
5772</div>
5773
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5774<!-- ======================================================================= -->
5775<div class="doc_subsection">
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5776 <a name="int_codegen">Code Generator Intrinsics</a>
5777</div>
5778
5779<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5780
5781<p>These intrinsics are provided by LLVM to expose special features that may
5782 only be implemented with code generator support.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5783
5784</div>
5785
5786<!-- _______________________________________________________________________ -->
5787<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5788 <a name="int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5789</div>
5790
5791<div class="doc_text">
5792
5793<h5>Syntax:</h5>
5794<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]5795 declare i8 *@llvm.returnaddress(i32 &lt;level&gt;)
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5796</pre>
5797
5798<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5799<p>The '<tt>llvm.returnaddress</tt>' intrinsic attempts to compute a
5800 target-specific value indicating the return address of the current function
5801 or one of its callers.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5802
5803<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5804<p>The argument to this intrinsic indicates which function to return the address
5805 for. Zero indicates the calling function, one indicates its caller, etc.
5806 The argument is <b>required</b> to be a constant integer value.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5807
5808<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5809<p>The '<tt>llvm.returnaddress</tt>' intrinsic either returns a pointer
5810 indicating the return address of the specified call frame, or zero if it
5811 cannot be identified. The value returned by this intrinsic is likely to be
5812 incorrect or 0 for arguments other than zero, so it should only be used for
5813 debugging purposes.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5814
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5815<p>Note that calling this intrinsic does not prevent function inlining or other
5816 aggressive transformations, so the value returned may not be that of the
5817 obvious source-language caller.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5818
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5819</div>
5820
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5821<!-- _______________________________________________________________________ -->
5822<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5823 <a name="int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5824</div>
5825
5826<div class="doc_text">
5827
5828<h5>Syntax:</h5>
5829<pre>
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]5830 declare i8* @llvm.frameaddress(i32 &lt;level&gt;)
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5831</pre>
5832
5833<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5834<p>The '<tt>llvm.frameaddress</tt>' intrinsic attempts to return the
5835 target-specific frame pointer value for the specified stack frame.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5836
5837<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5838<p>The argument to this intrinsic indicates which function to return the frame
5839 pointer for. Zero indicates the calling function, one indicates its caller,
5840 etc. The argument is <b>required</b> to be a constant integer value.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5841
5842<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5843<p>The '<tt>llvm.frameaddress</tt>' intrinsic either returns a pointer
5844 indicating the frame address of the specified call frame, or zero if it
5845 cannot be identified. The value returned by this intrinsic is likely to be
5846 incorrect or 0 for arguments other than zero, so it should only be used for
5847 debugging purposes.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5848
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5849<p>Note that calling this intrinsic does not prevent function inlining or other
5850 aggressive transformations, so the value returned may not be that of the
5851 obvious source-language caller.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5852
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5853</div>
5854
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]5855<!-- _______________________________________________________________________ -->
5856<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5857 <a name="int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]5858</div>
5859
5860<div class="doc_text">
5861
5862<h5>Syntax:</h5>
5863<pre>
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]5864 declare i8* @llvm.stacksave()
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]5865</pre>
5866
5867<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5868<p>The '<tt>llvm.stacksave</tt>' intrinsic is used to remember the current state
5869 of the function stack, for use
5870 with <a href="#int_stackrestore"> <tt>llvm.stackrestore</tt></a>. This is
5871 useful for implementing language features like scoped automatic variable
5872 sized arrays in C99.</p>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]5873
5874<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5875<p>This intrinsic returns a opaque pointer value that can be passed
5876 to <a href="#int_stackrestore"><tt>llvm.stackrestore</tt></a>. When
5877 an <tt>llvm.stackrestore</tt> intrinsic is executed with a value saved
5878 from <tt>llvm.stacksave</tt>, it effectively restores the state of the stack
5879 to the state it was in when the <tt>llvm.stacksave</tt> intrinsic executed.
5880 In practice, this pops any <a href="#i_alloca">alloca</a> blocks from the
5881 stack that were allocated after the <tt>llvm.stacksave</tt> was executed.</p>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]5882
5883</div>
5884
5885<!-- _______________________________________________________________________ -->
5886<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5887 <a name="int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]5888</div>
5889
5890<div class="doc_text">
5891
5892<h5>Syntax:</h5>
5893<pre>
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]5894 declare void @llvm.stackrestore(i8* %ptr)
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]5895</pre>
5896
5897<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5898<p>The '<tt>llvm.stackrestore</tt>' intrinsic is used to restore the state of
5899 the function stack to the state it was in when the
5900 corresponding <a href="#int_stacksave"><tt>llvm.stacksave</tt></a> intrinsic
5901 executed. This is useful for implementing language features like scoped
5902 automatic variable sized arrays in C99.</p>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]5903
5904<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5905<p>See the description
5906 for <a href="#int_stacksave"><tt>llvm.stacksave</tt></a>.</p>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]5907
5908</div>
5909
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]5910<!-- _______________________________________________________________________ -->
5911<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5912 <a name="int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a>
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]5913</div>
5914
5915<div class="doc_text">
5916
5917<h5>Syntax:</h5>
5918<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]5919 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]5920</pre>
5921
5922<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5923<p>The '<tt>llvm.prefetch</tt>' intrinsic is a hint to the code generator to
5924 insert a prefetch instruction if supported; otherwise, it is a noop.
5925 Prefetches have no effect on the behavior of the program but can change its
5926 performance characteristics.</p>
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]5927
5928<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5929<p><tt>address</tt> is the address to be prefetched, <tt>rw</tt> is the
5930 specifier determining if the fetch should be for a read (0) or write (1),
5931 and <tt>locality</tt> is a temporal locality specifier ranging from (0) - no
5932 locality, to (3) - extremely local keep in cache. The <tt>rw</tt>
5933 and <tt>locality</tt> arguments must be constant integers.</p>
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]5934
5935<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5936<p>This intrinsic does not modify the behavior of the program. In particular,
5937 prefetches cannot trap and do not produce a value. On targets that support
5938 this intrinsic, the prefetch can provide hints to the processor cache for
5939 better performance.</p>
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]5940
5941</div>
5942
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]5943<!-- _______________________________________________________________________ -->
5944<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5945 <a name="int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a>
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]5946</div>
5947
5948<div class="doc_text">
5949
5950<h5>Syntax:</h5>
5951<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]5952 declare void @llvm.pcmarker(i32 &lt;id&gt;)
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]5953</pre>
5954
5955<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5956<p>The '<tt>llvm.pcmarker</tt>' intrinsic is a method to export a Program
5957 Counter (PC) in a region of code to simulators and other tools. The method
5958 is target specific, but it is expected that the marker will use exported
5959 symbols to transmit the PC of the marker. The marker makes no guarantees
5960 that it will remain with any specific instruction after optimizations. It is
5961 possible that the presence of a marker will inhibit optimizations. The
5962 intended use is to be inserted after optimizations to allow correlations of
5963 simulation runs.</p>
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]5964
5965<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5966<p><tt>id</tt> is a numerical id identifying the marker.</p>
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]5967
5968<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5969<p>This intrinsic does not modify the behavior of the program. Backends that do
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]5970 not support this intrinsic may ignore it.</p>
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]5971
5972</div>
5973
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]5974<!-- _______________________________________________________________________ -->
5975<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5976 <a name="int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a>
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]5977</div>
5978
5979<div class="doc_text">
5980
5981<h5>Syntax:</h5>
5982<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]5983 declare i64 @llvm.readcyclecounter()
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]5984</pre>
5985
5986<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5987<p>The '<tt>llvm.readcyclecounter</tt>' intrinsic provides access to the cycle
5988 counter register (or similar low latency, high accuracy clocks) on those
5989 targets that support it. On X86, it should map to RDTSC. On Alpha, it
5990 should map to RPCC. As the backing counters overflow quickly (on the order
5991 of 9 seconds on alpha), this should only be used for small timings.</p>
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]5992
5993<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5994<p>When directly supported, reading the cycle counter should not modify any
5995 memory. Implementations are allowed to either return a application specific
5996 value or a system wide value. On backends without support, this is lowered
5997 to a constant 0.</p>
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]5998
5999</div>
6000
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6001<!-- ======================================================================= -->
6002<div class="doc_subsection">
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6003 <a name="int_libc">Standard C Library Intrinsics</a>
6004</div>
6005
6006<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6007
6008<p>LLVM provides intrinsics for a few important standard C library functions.
6009 These intrinsics allow source-language front-ends to pass information about
6010 the alignment of the pointer arguments to the code generator, providing
6011 opportunity for more efficient code generation.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6012
6013</div>
6014
6015<!-- _______________________________________________________________________ -->
6016<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6017 <a name="int_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6018</div>
6019
6020<div class="doc_text">
6021
6022<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6023<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]6024 integer bit width and for different address spaces. Not all targets support
6025 all bit widths however.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6026
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6027<pre>
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]6028 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]6029 i32 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]6030 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]6031 i64 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6032</pre>
6033
6034<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6035<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
6036 source location to the destination location.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6037
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6038<p>Note that, unlike the standard libc function, the <tt>llvm.memcpy.*</tt>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6039 intrinsics do not return a value, takes extra alignment/isvolatile arguments
6040 and the pointers can be in specified address spaces.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6041
6042<h5>Arguments:</h5>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6043
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6044<p>The first argument is a pointer to the destination, the second is a pointer
6045 to the source. The third argument is an integer argument specifying the
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6046 number of bytes to copy, the fourth argument is the alignment of the
6047 source and destination locations, and the fifth is a boolean indicating a
6048 volatile access.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6049
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]6050<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]6051 then the caller guarantees that both the source and destination pointers are
6052 aligned to that boundary.</p>
Chris Lattner4c67c482004-02-12 21:18:15 +0000[diff] [blame]6053
Jeffrey Yasskin5d284ae2010-04-26 21:21:24 +0000[diff] [blame]6054<p>If the <tt>isvolatile</tt> parameter is <tt>true</tt>, the
6055 <tt>llvm.memcpy</tt> call is a <a href="#volatile">volatile operation</a>.
6056 The detailed access behavior is not very cleanly specified and it is unwise
6057 to depend on it.</p>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6058
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6059<h5>Semantics:</h5>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6060
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6061<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
6062 source location to the destination location, which are not allowed to
6063 overlap. It copies "len" bytes of memory over. If the argument is known to
6064 be aligned to some boundary, this can be specified as the fourth argument,
6065 otherwise it should be set to 0 or 1.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6066
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6067</div>
6068
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6069<!-- _______________________________________________________________________ -->
6070<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6071 <a name="int_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a>
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6072</div>
6073
6074<div class="doc_text">
6075
6076<h5>Syntax:</h5>
Chris Lattnerdd708342008-11-21 16:42:48 +0000[diff] [blame]6077<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]6078 width and for different address space. Not all targets support all bit
6079 widths however.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6080
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6081<pre>
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]6082 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]6083 i32 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]6084 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]6085 i64 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6086</pre>
6087
6088<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6089<p>The '<tt>llvm.memmove.*</tt>' intrinsics move a block of memory from the
6090 source location to the destination location. It is similar to the
6091 '<tt>llvm.memcpy</tt>' intrinsic but allows the two memory locations to
6092 overlap.</p>
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6093
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6094<p>Note that, unlike the standard libc function, the <tt>llvm.memmove.*</tt>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6095 intrinsics do not return a value, takes extra alignment/isvolatile arguments
6096 and the pointers can be in specified address spaces.</p>
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6097
6098<h5>Arguments:</h5>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6099
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6100<p>The first argument is a pointer to the destination, the second is a pointer
6101 to the source. The third argument is an integer argument specifying the
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6102 number of bytes to copy, the fourth argument is the alignment of the
6103 source and destination locations, and the fifth is a boolean indicating a
6104 volatile access.</p>
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6105
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]6106<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]6107 then the caller guarantees that the source and destination pointers are
6108 aligned to that boundary.</p>
Chris Lattner4c67c482004-02-12 21:18:15 +0000[diff] [blame]6109
Jeffrey Yasskin5d284ae2010-04-26 21:21:24 +0000[diff] [blame]6110<p>If the <tt>isvolatile</tt> parameter is <tt>true</tt>, the
6111 <tt>llvm.memmove</tt> call is a <a href="#volatile">volatile operation</a>.
6112 The detailed access behavior is not very cleanly specified and it is unwise
6113 to depend on it.</p>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6114
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6115<h5>Semantics:</h5>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6116
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6117<p>The '<tt>llvm.memmove.*</tt>' intrinsics copy a block of memory from the
6118 source location to the destination location, which may overlap. It copies
6119 "len" bytes of memory over. If the argument is known to be aligned to some
6120 boundary, this can be specified as the fourth argument, otherwise it should
6121 be set to 0 or 1.</p>
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6122
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6123</div>
6124
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6125<!-- _______________________________________________________________________ -->
6126<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6127 <a name="int_memset">'<tt>llvm.memset.*</tt>' Intrinsics</a>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6128</div>
6129
6130<div class="doc_text">
6131
6132<h5>Syntax:</h5>
Chris Lattnerdd708342008-11-21 16:42:48 +0000[diff] [blame]6133<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]6134 width and for different address spaces. However, not all targets support all
6135 bit widths.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6136
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6137<pre>
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]6138 declare void @llvm.memset.p0i8.i32(i8* &lt;dest&gt;, i8 &lt;val&gt;,
Chris Lattner685db9d2010-04-08 00:54:34 +0000[diff] [blame]6139 i32 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]6140 declare void @llvm.memset.p0i8.i64(i8* &lt;dest&gt;, i8 &lt;val&gt;,
Chris Lattner685db9d2010-04-08 00:54:34 +0000[diff] [blame]6141 i64 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6142</pre>
6143
6144<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6145<p>The '<tt>llvm.memset.*</tt>' intrinsics fill a block of memory with a
6146 particular byte value.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6147
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6148<p>Note that, unlike the standard libc function, the <tt>llvm.memset</tt>
John Criswellad05ae42010-07-30 16:30:28 +0000[diff] [blame]6149 intrinsic does not return a value and takes extra alignment/volatile
6150 arguments. Also, the destination can be in an arbitrary address space.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6151
6152<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6153<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]6154 byte value with which to fill it, the third argument is an integer argument
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6155 specifying the number of bytes to fill, and the fourth argument is the known
John Criswellad05ae42010-07-30 16:30:28 +0000[diff] [blame]6156 alignment of the destination location.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6157
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]6158<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]6159 then the caller guarantees that the destination pointer is aligned to that
6160 boundary.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6161
Jeffrey Yasskin5d284ae2010-04-26 21:21:24 +0000[diff] [blame]6162<p>If the <tt>isvolatile</tt> parameter is <tt>true</tt>, the
6163 <tt>llvm.memset</tt> call is a <a href="#volatile">volatile operation</a>.
6164 The detailed access behavior is not very cleanly specified and it is unwise
6165 to depend on it.</p>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6166
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6167<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6168<p>The '<tt>llvm.memset.*</tt>' intrinsics fill "len" bytes of memory starting
6169 at the destination location. If the argument is known to be aligned to some
6170 boundary, this can be specified as the fourth argument, otherwise it should
6171 be set to 0 or 1.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6172
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6173</div>
6174
Chris Lattner3b4f4372004-06-11 02:28:03 +0000[diff] [blame]6175<!-- _______________________________________________________________________ -->
6176<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6177 <a name="int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a>
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]6178</div>
6179
6180<div class="doc_text">
6181
6182<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6183<p>This is an overloaded intrinsic. You can use <tt>llvm.sqrt</tt> on any
6184 floating point or vector of floating point type. Not all targets support all
6185 types however.</p>
6186
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]6187<pre>
Dale Johannesendd89d272007-10-02 17:47:38 +0000[diff] [blame]6188 declare float @llvm.sqrt.f32(float %Val)
6189 declare double @llvm.sqrt.f64(double %Val)
6190 declare x86_fp80 @llvm.sqrt.f80(x86_fp80 %Val)
6191 declare fp128 @llvm.sqrt.f128(fp128 %Val)
6192 declare ppc_fp128 @llvm.sqrt.ppcf128(ppc_fp128 %Val)
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]6193</pre>
6194
6195<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6196<p>The '<tt>llvm.sqrt</tt>' intrinsics return the sqrt of the specified operand,
6197 returning the same value as the libm '<tt>sqrt</tt>' functions would.
6198 Unlike <tt>sqrt</tt> in libm, however, <tt>llvm.sqrt</tt> has undefined
6199 behavior for negative numbers other than -0.0 (which allows for better
6200 optimization, because there is no need to worry about errno being
6201 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]6202
6203<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6204<p>The argument and return value are floating point numbers of the same
6205 type.</p>
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]6206
6207<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6208<p>This function returns the sqrt of the specified operand if it is a
6209 nonnegative floating point number.</p>
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]6210
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]6211</div>
6212
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]6213<!-- _______________________________________________________________________ -->
6214<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6215 <a name="int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a>
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]6216</div>
6217
6218<div class="doc_text">
6219
6220<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6221<p>This is an overloaded intrinsic. You can use <tt>llvm.powi</tt> on any
6222 floating point or vector of floating point type. Not all targets support all
6223 types however.</p>
6224
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]6225<pre>
Dale Johannesendd89d272007-10-02 17:47:38 +0000[diff] [blame]6226 declare float @llvm.powi.f32(float %Val, i32 %power)
6227 declare double @llvm.powi.f64(double %Val, i32 %power)
6228 declare x86_fp80 @llvm.powi.f80(x86_fp80 %Val, i32 %power)
6229 declare fp128 @llvm.powi.f128(fp128 %Val, i32 %power)
6230 declare ppc_fp128 @llvm.powi.ppcf128(ppc_fp128 %Val, i32 %power)
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]6231</pre>
6232
6233<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6234<p>The '<tt>llvm.powi.*</tt>' intrinsics return the first operand raised to the
6235 specified (positive or negative) power. The order of evaluation of
6236 multiplications is not defined. When a vector of floating point type is
6237 used, the second argument remains a scalar integer value.</p>
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]6238
6239<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6240<p>The second argument is an integer power, and the first is a value to raise to
6241 that power.</p>
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]6242
6243<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6244<p>This function returns the first value raised to the second power with an
6245 unspecified sequence of rounding operations.</p>
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]6246
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]6247</div>
6248
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6249<!-- _______________________________________________________________________ -->
6250<div class="doc_subsubsection">
6251 <a name="int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a>
6252</div>
6253
6254<div class="doc_text">
6255
6256<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6257<p>This is an overloaded intrinsic. You can use <tt>llvm.sin</tt> on any
6258 floating point or vector of floating point type. Not all targets support all
6259 types however.</p>
6260
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6261<pre>
6262 declare float @llvm.sin.f32(float %Val)
6263 declare double @llvm.sin.f64(double %Val)
6264 declare x86_fp80 @llvm.sin.f80(x86_fp80 %Val)
6265 declare fp128 @llvm.sin.f128(fp128 %Val)
6266 declare ppc_fp128 @llvm.sin.ppcf128(ppc_fp128 %Val)
6267</pre>
6268
6269<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6270<p>The '<tt>llvm.sin.*</tt>' intrinsics return the sine of the operand.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6271
6272<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6273<p>The argument and return value are floating point numbers of the same
6274 type.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6275
6276<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6277<p>This function returns the sine of the specified operand, returning the same
6278 values as the libm <tt>sin</tt> functions would, and handles error conditions
6279 in the same way.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6280
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6281</div>
6282
6283<!-- _______________________________________________________________________ -->
6284<div class="doc_subsubsection">
6285 <a name="int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a>
6286</div>
6287
6288<div class="doc_text">
6289
6290<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6291<p>This is an overloaded intrinsic. You can use <tt>llvm.cos</tt> on any
6292 floating point or vector of floating point type. Not all targets support all
6293 types however.</p>
6294
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6295<pre>
6296 declare float @llvm.cos.f32(float %Val)
6297 declare double @llvm.cos.f64(double %Val)
6298 declare x86_fp80 @llvm.cos.f80(x86_fp80 %Val)
6299 declare fp128 @llvm.cos.f128(fp128 %Val)
6300 declare ppc_fp128 @llvm.cos.ppcf128(ppc_fp128 %Val)
6301</pre>
6302
6303<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6304<p>The '<tt>llvm.cos.*</tt>' intrinsics return the cosine of the operand.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6305
6306<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6307<p>The argument and return value are floating point numbers of the same
6308 type.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6309
6310<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6311<p>This function returns the cosine of the specified operand, returning the same
6312 values as the libm <tt>cos</tt> functions would, and handles error conditions
6313 in the same way.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6314
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6315</div>
6316
6317<!-- _______________________________________________________________________ -->
6318<div class="doc_subsubsection">
6319 <a name="int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a>
6320</div>
6321
6322<div class="doc_text">
6323
6324<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6325<p>This is an overloaded intrinsic. You can use <tt>llvm.pow</tt> on any
6326 floating point or vector of floating point type. Not all targets support all
6327 types however.</p>
6328
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6329<pre>
6330 declare float @llvm.pow.f32(float %Val, float %Power)
6331 declare double @llvm.pow.f64(double %Val, double %Power)
6332 declare x86_fp80 @llvm.pow.f80(x86_fp80 %Val, x86_fp80 %Power)
6333 declare fp128 @llvm.pow.f128(fp128 %Val, fp128 %Power)
6334 declare ppc_fp128 @llvm.pow.ppcf128(ppc_fp128 %Val, ppc_fp128 Power)
6335</pre>
6336
6337<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6338<p>The '<tt>llvm.pow.*</tt>' intrinsics return the first operand raised to the
6339 specified (positive or negative) power.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6340
6341<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6342<p>The second argument is a floating point power, and the first is a value to
6343 raise to that power.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6344
6345<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6346<p>This function returns the first value raised to the second power, returning
6347 the same values as the libm <tt>pow</tt> functions would, and handles error
6348 conditions in the same way.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6349
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6350</div>
6351
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6352<!-- ======================================================================= -->
6353<div class="doc_subsection">
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]6354 <a name="int_manip">Bit Manipulation Intrinsics</a>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6355</div>
6356
6357<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6358
6359<p>LLVM provides intrinsics for a few important bit manipulation operations.
6360 These allow efficient code generation for some algorithms.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6361
6362</div>
6363
6364<!-- _______________________________________________________________________ -->
6365<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6366 <a name="int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a>
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]6367</div>
6368
6369<div class="doc_text">
6370
6371<h5>Syntax:</h5>
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]6372<p>This is an overloaded intrinsic function. You can use bswap on any integer
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6373 type that is an even number of bytes (i.e. BitWidth % 16 == 0).</p>
6374
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]6375<pre>
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]6376 declare i16 @llvm.bswap.i16(i16 &lt;id&gt;)
6377 declare i32 @llvm.bswap.i32(i32 &lt;id&gt;)
6378 declare i64 @llvm.bswap.i64(i64 &lt;id&gt;)
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]6379</pre>
6380
6381<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6382<p>The '<tt>llvm.bswap</tt>' family of intrinsics is used to byte swap integer
6383 values with an even number of bytes (positive multiple of 16 bits). These
6384 are useful for performing operations on data that is not in the target's
6385 native byte order.</p>
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]6386
6387<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6388<p>The <tt>llvm.bswap.i16</tt> intrinsic returns an i16 value that has the high
6389 and low byte of the input i16 swapped. Similarly,
6390 the <tt>llvm.bswap.i32</tt> intrinsic returns an i32 value that has the four
6391 bytes of the input i32 swapped, so that if the input bytes are numbered 0, 1,
6392 2, 3 then the returned i32 will have its bytes in 3, 2, 1, 0 order.
6393 The <tt>llvm.bswap.i48</tt>, <tt>llvm.bswap.i64</tt> and other intrinsics
6394 extend this concept to additional even-byte lengths (6 bytes, 8 bytes and
6395 more, respectively).</p>
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]6396
6397</div>
6398
6399<!-- _______________________________________________________________________ -->
6400<div class="doc_subsubsection">
Reid Spencerb4f9a6f2006-01-16 21:12:35 +0000[diff] [blame]6401 <a name="int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic</a>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6402</div>
6403
6404<div class="doc_text">
6405
6406<h5>Syntax:</h5>
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]6407<p>This is an overloaded intrinsic. You can use llvm.ctpop on any integer bit
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6408 width. Not all targets support all bit widths however.</p>
6409
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6410<pre>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6411 declare i8 @llvm.ctpop.i8(i8 &lt;src&gt;)
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]6412 declare i16 @llvm.ctpop.i16(i16 &lt;src&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]6413 declare i32 @llvm.ctpop.i32(i32 &lt;src&gt;)
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]6414 declare i64 @llvm.ctpop.i64(i64 &lt;src&gt;)
6415 declare i256 @llvm.ctpop.i256(i256 &lt;src&gt;)
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6416</pre>
6417
6418<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6419<p>The '<tt>llvm.ctpop</tt>' family of intrinsics counts the number of bits set
6420 in a value.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6421
6422<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6423<p>The only argument is the value to be counted. The argument may be of any
6424 integer type. The return type must match the argument type.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6425
6426<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6427<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]6428
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6429</div>
6430
6431<!-- _______________________________________________________________________ -->
6432<div class="doc_subsubsection">
Chris Lattnerb748c672006-01-16 22:34:14 +0000[diff] [blame]6433 <a name="int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic</a>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6434</div>
6435
6436<div class="doc_text">
6437
6438<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6439<p>This is an overloaded intrinsic. You can use <tt>llvm.ctlz</tt> on any
6440 integer bit width. Not all targets support all bit widths however.</p>
6441
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6442<pre>
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]6443 declare i8 @llvm.ctlz.i8 (i8 &lt;src&gt;)
6444 declare i16 @llvm.ctlz.i16(i16 &lt;src&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]6445 declare i32 @llvm.ctlz.i32(i32 &lt;src&gt;)
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]6446 declare i64 @llvm.ctlz.i64(i64 &lt;src&gt;)
6447 declare i256 @llvm.ctlz.i256(i256 &lt;src&gt;)
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6448</pre>
6449
6450<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6451<p>The '<tt>llvm.ctlz</tt>' family of intrinsic functions counts the number of
6452 leading zeros in a variable.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6453
6454<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6455<p>The only argument is the value to be counted. The argument may be of any
6456 integer type. The return type must match the argument type.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6457
6458<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6459<p>The '<tt>llvm.ctlz</tt>' intrinsic counts the leading (most significant)
6460 zeros in a variable. If the src == 0 then the result is the size in bits of
6461 the type of src. For example, <tt>llvm.ctlz(i32 2) = 30</tt>.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6462
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6463</div>
Chris Lattner3b4f4372004-06-11 02:28:03 +0000[diff] [blame]6464
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]6465<!-- _______________________________________________________________________ -->
6466<div class="doc_subsubsection">
Chris Lattnerb748c672006-01-16 22:34:14 +0000[diff] [blame]6467 <a name="int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic</a>
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]6468</div>
6469
6470<div class="doc_text">
6471
6472<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6473<p>This is an overloaded intrinsic. You can use <tt>llvm.cttz</tt> on any
6474 integer bit width. Not all targets support all bit widths however.</p>
6475
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]6476<pre>
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]6477 declare i8 @llvm.cttz.i8 (i8 &lt;src&gt;)
6478 declare i16 @llvm.cttz.i16(i16 &lt;src&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]6479 declare i32 @llvm.cttz.i32(i32 &lt;src&gt;)
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]6480 declare i64 @llvm.cttz.i64(i64 &lt;src&gt;)
6481 declare i256 @llvm.cttz.i256(i256 &lt;src&gt;)
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]6482</pre>
6483
6484<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6485<p>The '<tt>llvm.cttz</tt>' family of intrinsic functions counts the number of
6486 trailing zeros.</p>
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]6487
6488<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6489<p>The only argument is the value to be counted. The argument may be of any
6490 integer type. The return type must match the argument type.</p>
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]6491
6492<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6493<p>The '<tt>llvm.cttz</tt>' intrinsic counts the trailing (least significant)
6494 zeros in a variable. If the src == 0 then the result is the size in bits of
6495 the type of src. For example, <tt>llvm.cttz(2) = 1</tt>.</p>
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]6496
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]6497</div>
6498
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]6499<!-- ======================================================================= -->
6500<div class="doc_subsection">
6501 <a name="int_overflow">Arithmetic with Overflow Intrinsics</a>
6502</div>
6503
6504<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6505
6506<p>LLVM provides intrinsics for some arithmetic with overflow operations.</p>
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]6507
6508</div>
6509
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6510<!-- _______________________________________________________________________ -->
6511<div class="doc_subsubsection">
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]6512 <a name="int_sadd_overflow">'<tt>llvm.sadd.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6513</div>
6514
6515<div class="doc_text">
6516
6517<h5>Syntax:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6518<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]6519 on any integer bit width.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6520
6521<pre>
6522 declare {i16, i1} @llvm.sadd.with.overflow.i16(i16 %a, i16 %b)
6523 declare {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
6524 declare {i64, i1} @llvm.sadd.with.overflow.i64(i64 %a, i64 %b)
6525</pre>
6526
6527<h5>Overview:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6528<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6529 a signed addition of the two arguments, and indicate whether an overflow
6530 occurred during the signed summation.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6531
6532<h5>Arguments:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6533<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]6534 be of integer types of any bit width, but they must have the same bit
6535 width. The second element of the result structure must be of
6536 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6537 undergo signed addition.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6538
6539<h5>Semantics:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6540<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6541 a signed addition of the two variables. They return a structure &mdash; the
6542 first element of which is the signed summation, and the second element of
6543 which is a bit specifying if the signed summation resulted in an
6544 overflow.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6545
6546<h5>Examples:</h5>
6547<pre>
6548 %res = call {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
6549 %sum = extractvalue {i32, i1} %res, 0
6550 %obit = extractvalue {i32, i1} %res, 1
6551 br i1 %obit, label %overflow, label %normal
6552</pre>
6553
6554</div>
6555
6556<!-- _______________________________________________________________________ -->
6557<div class="doc_subsubsection">
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]6558 <a name="int_uadd_overflow">'<tt>llvm.uadd.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6559</div>
6560
6561<div class="doc_text">
6562
6563<h5>Syntax:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6564<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]6565 on any integer bit width.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6566
6567<pre>
6568 declare {i16, i1} @llvm.uadd.with.overflow.i16(i16 %a, i16 %b)
6569 declare {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
6570 declare {i64, i1} @llvm.uadd.with.overflow.i64(i64 %a, i64 %b)
6571</pre>
6572
6573<h5>Overview:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6574<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6575 an unsigned addition of the two arguments, and indicate whether a carry
6576 occurred during the unsigned summation.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6577
6578<h5>Arguments:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6579<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]6580 be of integer types of any bit width, but they must have the same bit
6581 width. The second element of the result structure must be of
6582 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6583 undergo unsigned addition.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6584
6585<h5>Semantics:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6586<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6587 an unsigned addition of the two arguments. They return a structure &mdash;
6588 the first element of which is the sum, and the second element of which is a
6589 bit specifying if the unsigned summation resulted in a carry.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6590
6591<h5>Examples:</h5>
6592<pre>
6593 %res = call {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
6594 %sum = extractvalue {i32, i1} %res, 0
6595 %obit = extractvalue {i32, i1} %res, 1
6596 br i1 %obit, label %carry, label %normal
6597</pre>
6598
6599</div>
6600
6601<!-- _______________________________________________________________________ -->
6602<div class="doc_subsubsection">
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]6603 <a name="int_ssub_overflow">'<tt>llvm.ssub.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6604</div>
6605
6606<div class="doc_text">
6607
6608<h5>Syntax:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6609<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]6610 on any integer bit width.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6611
6612<pre>
6613 declare {i16, i1} @llvm.ssub.with.overflow.i16(i16 %a, i16 %b)
6614 declare {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
6615 declare {i64, i1} @llvm.ssub.with.overflow.i64(i64 %a, i64 %b)
6616</pre>
6617
6618<h5>Overview:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6619<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6620 a signed subtraction of the two arguments, and indicate whether an overflow
6621 occurred during the signed subtraction.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6622
6623<h5>Arguments:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6624<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]6625 be of integer types of any bit width, but they must have the same bit
6626 width. The second element of the result structure must be of
6627 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6628 undergo signed subtraction.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6629
6630<h5>Semantics:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6631<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6632 a signed subtraction of the two arguments. They return a structure &mdash;
6633 the first element of which is the subtraction, and the second element of
6634 which is a bit specifying if the signed subtraction resulted in an
6635 overflow.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6636
6637<h5>Examples:</h5>
6638<pre>
6639 %res = call {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
6640 %sum = extractvalue {i32, i1} %res, 0
6641 %obit = extractvalue {i32, i1} %res, 1
6642 br i1 %obit, label %overflow, label %normal
6643</pre>
6644
6645</div>
6646
6647<!-- _______________________________________________________________________ -->
6648<div class="doc_subsubsection">
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]6649 <a name="int_usub_overflow">'<tt>llvm.usub.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6650</div>
6651
6652<div class="doc_text">
6653
6654<h5>Syntax:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6655<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]6656 on any integer bit width.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6657
6658<pre>
6659 declare {i16, i1} @llvm.usub.with.overflow.i16(i16 %a, i16 %b)
6660 declare {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
6661 declare {i64, i1} @llvm.usub.with.overflow.i64(i64 %a, i64 %b)
6662</pre>
6663
6664<h5>Overview:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6665<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6666 an unsigned subtraction of the two arguments, and indicate whether an
6667 overflow occurred during the unsigned subtraction.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6668
6669<h5>Arguments:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6670<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]6671 be of integer types of any bit width, but they must have the same bit
6672 width. The second element of the result structure must be of
6673 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6674 undergo unsigned subtraction.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6675
6676<h5>Semantics:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6677<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6678 an unsigned subtraction of the two arguments. They return a structure &mdash;
6679 the first element of which is the subtraction, and the second element of
6680 which is a bit specifying if the unsigned subtraction resulted in an
6681 overflow.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6682
6683<h5>Examples:</h5>
6684<pre>
6685 %res = call {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
6686 %sum = extractvalue {i32, i1} %res, 0
6687 %obit = extractvalue {i32, i1} %res, 1
6688 br i1 %obit, label %overflow, label %normal
6689</pre>
6690
6691</div>
6692
6693<!-- _______________________________________________________________________ -->
6694<div class="doc_subsubsection">
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]6695 <a name="int_smul_overflow">'<tt>llvm.smul.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6696</div>
6697
6698<div class="doc_text">
6699
6700<h5>Syntax:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6701<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]6702 on any integer bit width.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6703
6704<pre>
6705 declare {i16, i1} @llvm.smul.with.overflow.i16(i16 %a, i16 %b)
6706 declare {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
6707 declare {i64, i1} @llvm.smul.with.overflow.i64(i64 %a, i64 %b)
6708</pre>
6709
6710<h5>Overview:</h5>
6711
6712<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6713 a signed multiplication of the two arguments, and indicate whether an
6714 overflow occurred during the signed multiplication.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6715
6716<h5>Arguments:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6717<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]6718 be of integer types of any bit width, but they must have the same bit
6719 width. The second element of the result structure must be of
6720 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6721 undergo signed multiplication.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6722
6723<h5>Semantics:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6724<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6725 a signed multiplication of the two arguments. They return a structure &mdash;
6726 the first element of which is the multiplication, and the second element of
6727 which is a bit specifying if the signed multiplication resulted in an
6728 overflow.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6729
6730<h5>Examples:</h5>
6731<pre>
6732 %res = call {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
6733 %sum = extractvalue {i32, i1} %res, 0
6734 %obit = extractvalue {i32, i1} %res, 1
6735 br i1 %obit, label %overflow, label %normal
6736</pre>
6737
Reid Spencer5bf54c82007-04-11 23:23:49 +0000[diff] [blame]6738</div>
6739
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]6740<!-- _______________________________________________________________________ -->
6741<div class="doc_subsubsection">
6742 <a name="int_umul_overflow">'<tt>llvm.umul.with.overflow.*</tt>' Intrinsics</a>
6743</div>
6744
6745<div class="doc_text">
6746
6747<h5>Syntax:</h5>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]6748<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]6749 on any integer bit width.</p>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]6750
6751<pre>
6752 declare {i16, i1} @llvm.umul.with.overflow.i16(i16 %a, i16 %b)
6753 declare {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
6754 declare {i64, i1} @llvm.umul.with.overflow.i64(i64 %a, i64 %b)
6755</pre>
6756
6757<h5>Overview:</h5>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]6758<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6759 a unsigned multiplication of the two arguments, and indicate whether an
6760 overflow occurred during the unsigned multiplication.</p>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]6761
6762<h5>Arguments:</h5>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]6763<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]6764 be of integer types of any bit width, but they must have the same bit
6765 width. The second element of the result structure must be of
6766 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6767 undergo unsigned multiplication.</p>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]6768
6769<h5>Semantics:</h5>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]6770<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6771 an unsigned multiplication of the two arguments. They return a structure
6772 &mdash; the first element of which is the multiplication, and the second
6773 element of which is a bit specifying if the unsigned multiplication resulted
6774 in an overflow.</p>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]6775
6776<h5>Examples:</h5>
6777<pre>
6778 %res = call {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
6779 %sum = extractvalue {i32, i1} %res, 0
6780 %obit = extractvalue {i32, i1} %res, 1
6781 br i1 %obit, label %overflow, label %normal
6782</pre>
6783
6784</div>
6785
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]6786<!-- ======================================================================= -->
6787<div class="doc_subsection">
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]6788 <a name="int_fp16">Half Precision Floating Point Intrinsics</a>
6789</div>
6790
6791<div class="doc_text">
6792
Chris Lattner022a9fb2010-03-15 04:12:21 +0000[diff] [blame]6793<p>Half precision floating point is a storage-only format. This means that it is
6794 a dense encoding (in memory) but does not support computation in the
6795 format.</p>
Chris Lattnerbbd8bd32010-03-14 23:03:31 +0000[diff] [blame]6796
Chris Lattner022a9fb2010-03-15 04:12:21 +0000[diff] [blame]6797<p>This means that code must first load the half-precision floating point
Chris Lattnerbbd8bd32010-03-14 23:03:31 +0000[diff] [blame]6798 value as an i16, then convert it to float with <a
6799 href="#int_convert_from_fp16"><tt>llvm.convert.from.fp16</tt></a>.
6800 Computation can then be performed on the float value (including extending to
Chris Lattner022a9fb2010-03-15 04:12:21 +0000[diff] [blame]6801 double etc). To store the value back to memory, it is first converted to
6802 float if needed, then converted to i16 with
Chris Lattnerbbd8bd32010-03-14 23:03:31 +0000[diff] [blame]6803 <a href="#int_convert_to_fp16"><tt>llvm.convert.to.fp16</tt></a>, then
6804 storing as an i16 value.</p>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]6805</div>
6806
6807<!-- _______________________________________________________________________ -->
6808<div class="doc_subsubsection">
Chris Lattnerbbd8bd32010-03-14 23:03:31 +0000[diff] [blame]6809 <a name="int_convert_to_fp16">'<tt>llvm.convert.to.fp16</tt>' Intrinsic</a>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]6810</div>
6811
6812<div class="doc_text">
6813
6814<h5>Syntax:</h5>
6815<pre>
6816 declare i16 @llvm.convert.to.fp16(f32 %a)
6817</pre>
6818
6819<h5>Overview:</h5>
6820<p>The '<tt>llvm.convert.to.fp16</tt>' intrinsic function performs
6821 a conversion from single precision floating point format to half precision
6822 floating point format.</p>
6823
6824<h5>Arguments:</h5>
6825<p>The intrinsic function contains single argument - the value to be
6826 converted.</p>
6827
6828<h5>Semantics:</h5>
6829<p>The '<tt>llvm.convert.to.fp16</tt>' intrinsic function performs
6830 a conversion from single precision floating point format to half precision
Chris Lattner022a9fb2010-03-15 04:12:21 +0000[diff] [blame]6831 floating point format. The return value is an <tt>i16</tt> which
Chris Lattnerbbd8bd32010-03-14 23:03:31 +0000[diff] [blame]6832 contains the converted number.</p>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]6833
6834<h5>Examples:</h5>
6835<pre>
6836 %res = call i16 @llvm.convert.to.fp16(f32 %a)
6837 store i16 %res, i16* @x, align 2
6838</pre>
6839
6840</div>
6841
6842<!-- _______________________________________________________________________ -->
6843<div class="doc_subsubsection">
Chris Lattnerbbd8bd32010-03-14 23:03:31 +0000[diff] [blame]6844 <a name="int_convert_from_fp16">'<tt>llvm.convert.from.fp16</tt>' Intrinsic</a>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]6845</div>
6846
6847<div class="doc_text">
6848
6849<h5>Syntax:</h5>
6850<pre>
6851 declare f32 @llvm.convert.from.fp16(i16 %a)
6852</pre>
6853
6854<h5>Overview:</h5>
6855<p>The '<tt>llvm.convert.from.fp16</tt>' intrinsic function performs
6856 a conversion from half precision floating point format to single precision
6857 floating point format.</p>
6858
6859<h5>Arguments:</h5>
6860<p>The intrinsic function contains single argument - the value to be
6861 converted.</p>
6862
6863<h5>Semantics:</h5>
6864<p>The '<tt>llvm.convert.from.fp16</tt>' intrinsic function performs a
Chris Lattner022a9fb2010-03-15 04:12:21 +0000[diff] [blame]6865 conversion from half single precision floating point format to single
Chris Lattnerbbd8bd32010-03-14 23:03:31 +0000[diff] [blame]6866 precision floating point format. The input half-float value is represented by
6867 an <tt>i16</tt> value.</p>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]6868
6869<h5>Examples:</h5>
6870<pre>
6871 %a = load i16* @x, align 2
6872 %res = call f32 @llvm.convert.from.fp16(i16 %a)
6873</pre>
6874
6875</div>
6876
6877<!-- ======================================================================= -->
6878<div class="doc_subsection">
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]6879 <a name="int_debugger">Debugger Intrinsics</a>
6880</div>
6881
6882<div class="doc_text">
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]6883
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6884<p>The LLVM debugger intrinsics (which all start with <tt>llvm.dbg.</tt>
6885 prefix), are described in
6886 the <a href="SourceLevelDebugging.html#format_common_intrinsics">LLVM Source
6887 Level Debugging</a> document.</p>
6888
6889</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]6890
Jim Laskey2211f492007-03-14 19:31:19 +0000[diff] [blame]6891<!-- ======================================================================= -->
6892<div class="doc_subsection">
6893 <a name="int_eh">Exception Handling Intrinsics</a>
6894</div>
6895
6896<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6897
6898<p>The LLVM exception handling intrinsics (which all start with
6899 <tt>llvm.eh.</tt> prefix), are described in
6900 the <a href="ExceptionHandling.html#format_common_intrinsics">LLVM Exception
6901 Handling</a> document.</p>
6902
Jim Laskey2211f492007-03-14 19:31:19 +0000[diff] [blame]6903</div>
6904
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]6905<!-- ======================================================================= -->
6906<div class="doc_subsection">
Duncan Sands86e01192007-09-11 14:10:23 +0000[diff] [blame]6907 <a name="int_trampoline">Trampoline Intrinsic</a>
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]6908</div>
6909
6910<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6911
6912<p>This intrinsic makes it possible to excise one parameter, marked with
Dan Gohman3770af52010-07-02 23:18:08 +0000[diff] [blame]6913 the <a href="#nest"><tt>nest</tt></a> attribute, from a function.
6914 The result is a callable
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6915 function pointer lacking the nest parameter - the caller does not need to
6916 provide a value for it. Instead, the value to use is stored in advance in a
6917 "trampoline", a block of memory usually allocated on the stack, which also
6918 contains code to splice the nest value into the argument list. This is used
6919 to implement the GCC nested function address extension.</p>
6920
6921<p>For example, if the function is
6922 <tt>i32 f(i8* nest %c, i32 %x, i32 %y)</tt> then the resulting function
6923 pointer has signature <tt>i32 (i32, i32)*</tt>. It can be created as
6924 follows:</p>
6925
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]6926<pre class="doc_code">
Duncan Sands86e01192007-09-11 14:10:23 +0000[diff] [blame]6927 %tramp = alloca [10 x i8], align 4 ; size and alignment only correct for X86
6928 %tramp1 = getelementptr [10 x i8]* %tramp, i32 0, i32 0
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]6929 %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]6930 %fp = bitcast i8* %p to i32 (i32, i32)*
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]6931</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6932
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]6933<p>The call <tt>%val = call i32 %fp(i32 %x, i32 %y)</tt> is then equivalent
6934 to <tt>%val = call i32 %f(i8* %nval, i32 %x, i32 %y)</tt>.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6935
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]6936</div>
6937
6938<!-- _______________________________________________________________________ -->
6939<div class="doc_subsubsection">
6940 <a name="int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a>
6941</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6942
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]6943<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6944
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]6945<h5>Syntax:</h5>
6946<pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6947 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]6948</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6949
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]6950<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6951<p>This fills the memory pointed to by <tt>tramp</tt> with code and returns a
6952 function pointer suitable for executing it.</p>
6953
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]6954<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6955<p>The <tt>llvm.init.trampoline</tt> intrinsic takes three arguments, all
6956 pointers. The <tt>tramp</tt> argument must point to a sufficiently large and
6957 sufficiently aligned block of memory; this memory is written to by the
6958 intrinsic. Note that the size and the alignment are target-specific - LLVM
6959 currently provides no portable way of determining them, so a front-end that
6960 generates this intrinsic needs to have some target-specific knowledge.
6961 The <tt>func</tt> argument must hold a function bitcast to
6962 an <tt>i8*</tt>.</p>
6963
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]6964<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6965<p>The block of memory pointed to by <tt>tramp</tt> is filled with target
6966 dependent code, turning it into a function. A pointer to this function is
6967 returned, but needs to be bitcast to an <a href="#int_trampoline">appropriate
6968 function pointer type</a> before being called. The new function's signature
6969 is the same as that of <tt>func</tt> with any arguments marked with
6970 the <tt>nest</tt> attribute removed. At most one such <tt>nest</tt> argument
6971 is allowed, and it must be of pointer type. Calling the new function is
6972 equivalent to calling <tt>func</tt> with the same argument list, but
6973 with <tt>nval</tt> used for the missing <tt>nest</tt> argument. If, after
6974 calling <tt>llvm.init.trampoline</tt>, the memory pointed to
6975 by <tt>tramp</tt> is modified, then the effect of any later call to the
6976 returned function pointer is undefined.</p>
6977
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]6978</div>
6979
6980<!-- ======================================================================= -->
6981<div class="doc_subsection">
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]6982 <a name="int_atomics">Atomic Operations and Synchronization Intrinsics</a>
6983</div>
6984
6985<div class="doc_text">
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]6986
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6987<p>These intrinsic functions expand the "universal IR" of LLVM to represent
6988 hardware constructs for atomic operations and memory synchronization. This
6989 provides an interface to the hardware, not an interface to the programmer. It
6990 is aimed at a low enough level to allow any programming models or APIs
6991 (Application Programming Interfaces) which need atomic behaviors to map
6992 cleanly onto it. It is also modeled primarily on hardware behavior. Just as
6993 hardware provides a "universal IR" for source languages, it also provides a
6994 starting point for developing a "universal" atomic operation and
6995 synchronization IR.</p>
6996
6997<p>These do <em>not</em> form an API such as high-level threading libraries,
6998 software transaction memory systems, atomic primitives, and intrinsic
6999 functions as found in BSD, GNU libc, atomic_ops, APR, and other system and
7000 application libraries. The hardware interface provided by LLVM should allow
7001 a clean implementation of all of these APIs and parallel programming models.
7002 No one model or paradigm should be selected above others unless the hardware
7003 itself ubiquitously does so.</p>
7004
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7005</div>
7006
7007<!-- _______________________________________________________________________ -->
7008<div class="doc_subsubsection">
7009 <a name="int_memory_barrier">'<tt>llvm.memory.barrier</tt>' Intrinsic</a>
7010</div>
7011<div class="doc_text">
7012<h5>Syntax:</h5>
7013<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7014 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]7015</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7016
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7017<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7018<p>The <tt>llvm.memory.barrier</tt> intrinsic guarantees ordering between
7019 specific pairs of memory access types.</p>
7020
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7021<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7022<p>The <tt>llvm.memory.barrier</tt> intrinsic requires five boolean arguments.
7023 The first four arguments enables a specific barrier as listed below. The
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]7024 fifth argument specifies that the barrier applies to io or device or uncached
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7025 memory.</p>
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7026
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7027<ul>
7028 <li><tt>ll</tt>: load-load barrier</li>
7029 <li><tt>ls</tt>: load-store barrier</li>
7030 <li><tt>sl</tt>: store-load barrier</li>
7031 <li><tt>ss</tt>: store-store barrier</li>
7032 <li><tt>device</tt>: barrier applies to device and uncached memory also.</li>
7033</ul>
7034
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7035<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7036<p>This intrinsic causes the system to enforce some ordering constraints upon
7037 the loads and stores of the program. This barrier does not
7038 indicate <em>when</em> any events will occur, it only enforces
7039 an <em>order</em> in which they occur. For any of the specified pairs of load
7040 and store operations (f.ex. load-load, or store-load), all of the first
7041 operations preceding the barrier will complete before any of the second
7042 operations succeeding the barrier begin. Specifically the semantics for each
7043 pairing is as follows:</p>
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7044
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7045<ul>
7046 <li><tt>ll</tt>: All loads before the barrier must complete before any load
7047 after the barrier begins.</li>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]7048 <li><tt>ls</tt>: All loads before the barrier must complete before any
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7049 store after the barrier begins.</li>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]7050 <li><tt>ss</tt>: All stores before the barrier must complete before any
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7051 store after the barrier begins.</li>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]7052 <li><tt>sl</tt>: All stores before the barrier must complete before any
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7053 load after the barrier begins.</li>
7054</ul>
7055
7056<p>These semantics are applied with a logical "and" behavior when more than one
7057 is enabled in a single memory barrier intrinsic.</p>
7058
7059<p>Backends may implement stronger barriers than those requested when they do
7060 not support as fine grained a barrier as requested. Some architectures do
7061 not need all types of barriers and on such architectures, these become
7062 noops.</p>
7063
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7064<h5>Example:</h5>
7065<pre>
Victor Hernandeza70c6df2009-10-26 23:44:29 +0000[diff] [blame]7066%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7067%ptr = bitcast i8* %mallocP to i32*
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7068 store i32 4, %ptr
7069
7070%result1 = load i32* %ptr <i>; yields {i32}:result1 = 4</i>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7071 call void @llvm.memory.barrier(i1 false, i1 true, i1 false, i1 false)
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7072 <i>; guarantee the above finishes</i>
7073 store i32 8, %ptr <i>; before this begins</i>
7074</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7075
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7076</div>
7077
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7078<!-- _______________________________________________________________________ -->
7079<div class="doc_subsubsection">
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7080 <a name="int_atomic_cmp_swap">'<tt>llvm.atomic.cmp.swap.*</tt>' Intrinsic</a>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7081</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7082
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7083<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7084
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7085<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7086<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.cmp.swap</tt> on
7087 any integer bit width and for different address spaces. Not all targets
7088 support all bit widths however.</p>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7089
7090<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7091 declare i8 @llvm.atomic.cmp.swap.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;cmp&gt;, i8 &lt;val&gt;)
7092 declare i16 @llvm.atomic.cmp.swap.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;cmp&gt;, i16 &lt;val&gt;)
7093 declare i32 @llvm.atomic.cmp.swap.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;cmp&gt;, i32 &lt;val&gt;)
7094 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]7095</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7096
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7097<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7098<p>This loads a value in memory and compares it to a given value. If they are
7099 equal, it stores a new value into the memory.</p>
7100
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7101<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7102<p>The <tt>llvm.atomic.cmp.swap</tt> intrinsic takes three arguments. The result
7103 as well as both <tt>cmp</tt> and <tt>val</tt> must be integer values with the
7104 same bit width. The <tt>ptr</tt> argument must be a pointer to a value of
7105 this integer type. While any bit width integer may be used, targets may only
7106 lower representations they support in hardware.</p>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7107
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7108<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7109<p>This entire intrinsic must be executed atomically. It first loads the value
7110 in memory pointed to by <tt>ptr</tt> and compares it with the
7111 value <tt>cmp</tt>. If they are equal, <tt>val</tt> is stored into the
7112 memory. The loaded value is yielded in all cases. This provides the
7113 equivalent of an atomic compare-and-swap operation within the SSA
7114 framework.</p>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7115
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7116<h5>Examples:</h5>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7117<pre>
Victor Hernandeza70c6df2009-10-26 23:44:29 +0000[diff] [blame]7118%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7119%ptr = bitcast i8* %mallocP to i32*
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7120 store i32 4, %ptr
7121
7122%val1 = add i32 4, 4
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7123%result1 = call i32 @llvm.atomic.cmp.swap.i32.p0i32(i32* %ptr, i32 4, %val1)
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7124 <i>; yields {i32}:result1 = 4</i>
7125%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
7126%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
7127
7128%val2 = add i32 1, 1
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7129%result2 = call i32 @llvm.atomic.cmp.swap.i32.p0i32(i32* %ptr, i32 5, %val2)
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7130 <i>; yields {i32}:result2 = 8</i>
7131%stored2 = icmp eq i32 %result2, 5 <i>; yields {i1}:stored2 = false</i>
7132
7133%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 8</i>
7134</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7135
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7136</div>
7137
7138<!-- _______________________________________________________________________ -->
7139<div class="doc_subsubsection">
7140 <a name="int_atomic_swap">'<tt>llvm.atomic.swap.*</tt>' Intrinsic</a>
7141</div>
7142<div class="doc_text">
7143<h5>Syntax:</h5>
7144
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7145<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.swap</tt> on any
7146 integer bit width. Not all targets support all bit widths however.</p>
7147
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7148<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7149 declare i8 @llvm.atomic.swap.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;val&gt;)
7150 declare i16 @llvm.atomic.swap.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;val&gt;)
7151 declare i32 @llvm.atomic.swap.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;val&gt;)
7152 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]7153</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7154
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7155<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7156<p>This intrinsic loads the value stored in memory at <tt>ptr</tt> and yields
7157 the value from memory. It then stores the value in <tt>val</tt> in the memory
7158 at <tt>ptr</tt>.</p>
7159
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7160<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7161<p>The <tt>llvm.atomic.swap</tt> intrinsic takes two arguments. Both
7162 the <tt>val</tt> argument and the result must be integers of the same bit
7163 width. The first argument, <tt>ptr</tt>, must be a pointer to a value of this
7164 integer type. The targets may only lower integer representations they
7165 support.</p>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7166
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7167<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7168<p>This intrinsic loads the value pointed to by <tt>ptr</tt>, yields it, and
7169 stores <tt>val</tt> back into <tt>ptr</tt> atomically. This provides the
7170 equivalent of an atomic swap operation within the SSA framework.</p>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7171
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7172<h5>Examples:</h5>
7173<pre>
Victor Hernandeza70c6df2009-10-26 23:44:29 +0000[diff] [blame]7174%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7175%ptr = bitcast i8* %mallocP to i32*
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7176 store i32 4, %ptr
7177
7178%val1 = add i32 4, 4
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7179%result1 = call i32 @llvm.atomic.swap.i32.p0i32(i32* %ptr, i32 %val1)
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7180 <i>; yields {i32}:result1 = 4</i>
7181%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
7182%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
7183
7184%val2 = add i32 1, 1
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7185%result2 = call i32 @llvm.atomic.swap.i32.p0i32(i32* %ptr, i32 %val2)
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7186 <i>; yields {i32}:result2 = 8</i>
7187
7188%stored2 = icmp eq i32 %result2, 8 <i>; yields {i1}:stored2 = true</i>
7189%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 2</i>
7190</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7191
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7192</div>
7193
7194<!-- _______________________________________________________________________ -->
7195<div class="doc_subsubsection">
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7196 <a name="int_atomic_load_add">'<tt>llvm.atomic.load.add.*</tt>' Intrinsic</a>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7197
7198</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7199
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7200<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7201
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7202<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7203<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.load.add</tt> on
7204 any integer bit width. Not all targets support all bit widths however.</p>
7205
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7206<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7207 declare i8 @llvm.atomic.load.add.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7208 declare i16 @llvm.atomic.load.add.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7209 declare i32 @llvm.atomic.load.add.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7210 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]7211</pre>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7212
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7213<h5>Overview:</h5>
7214<p>This intrinsic adds <tt>delta</tt> to the value stored in memory
7215 at <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.</p>
7216
7217<h5>Arguments:</h5>
7218<p>The intrinsic takes two arguments, the first a pointer to an integer value
7219 and the second an integer value. The result is also an integer value. These
7220 integer types can have any bit width, but they must all have the same bit
7221 width. The targets may only lower integer representations they support.</p>
7222
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7223<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7224<p>This intrinsic does a series of operations atomically. It first loads the
7225 value stored at <tt>ptr</tt>. It then adds <tt>delta</tt>, stores the result
7226 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]7227
7228<h5>Examples:</h5>
7229<pre>
Victor Hernandeza70c6df2009-10-26 23:44:29 +0000[diff] [blame]7230%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7231%ptr = bitcast i8* %mallocP to i32*
7232 store i32 4, %ptr
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7233%result1 = call i32 @llvm.atomic.load.add.i32.p0i32(i32* %ptr, i32 4)
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7234 <i>; yields {i32}:result1 = 4</i>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7235%result2 = call i32 @llvm.atomic.load.add.i32.p0i32(i32* %ptr, i32 2)
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7236 <i>; yields {i32}:result2 = 8</i>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7237%result3 = call i32 @llvm.atomic.load.add.i32.p0i32(i32* %ptr, i32 5)
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7238 <i>; yields {i32}:result3 = 10</i>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7239%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 15</i>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7240</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7241
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7242</div>
7243
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7244<!-- _______________________________________________________________________ -->
7245<div class="doc_subsubsection">
7246 <a name="int_atomic_load_sub">'<tt>llvm.atomic.load.sub.*</tt>' Intrinsic</a>
7247
7248</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7249
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7250<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7251
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7252<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7253<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.load.sub</tt> on
7254 any integer bit width and for different address spaces. Not all targets
7255 support all bit widths however.</p>
7256
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7257<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7258 declare i8 @llvm.atomic.load.sub.i8.p0i32(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7259 declare i16 @llvm.atomic.load.sub.i16.p0i32(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7260 declare i32 @llvm.atomic.load.sub.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7261 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]7262</pre>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7263
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7264<h5>Overview:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]7265<p>This intrinsic subtracts <tt>delta</tt> to the value stored in memory at
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7266 <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.</p>
7267
7268<h5>Arguments:</h5>
7269<p>The intrinsic takes two arguments, the first a pointer to an integer value
7270 and the second an integer value. The result is also an integer value. These
7271 integer types can have any bit width, but they must all have the same bit
7272 width. The targets may only lower integer representations they support.</p>
7273
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7274<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7275<p>This intrinsic does a series of operations atomically. It first loads the
7276 value stored at <tt>ptr</tt>. It then subtracts <tt>delta</tt>, stores the
7277 result to <tt>ptr</tt>. It yields the original value stored
7278 at <tt>ptr</tt>.</p>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7279
7280<h5>Examples:</h5>
7281<pre>
Victor Hernandeza70c6df2009-10-26 23:44:29 +0000[diff] [blame]7282%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7283%ptr = bitcast i8* %mallocP to i32*
7284 store i32 8, %ptr
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7285%result1 = call i32 @llvm.atomic.load.sub.i32.p0i32(i32* %ptr, i32 4)
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7286 <i>; yields {i32}:result1 = 8</i>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7287%result2 = call i32 @llvm.atomic.load.sub.i32.p0i32(i32* %ptr, i32 2)
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7288 <i>; yields {i32}:result2 = 4</i>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7289%result3 = call i32 @llvm.atomic.load.sub.i32.p0i32(i32* %ptr, i32 5)
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7290 <i>; yields {i32}:result3 = 2</i>
7291%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = -3</i>
7292</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7293
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7294</div>
7295
7296<!-- _______________________________________________________________________ -->
7297<div class="doc_subsubsection">
7298 <a name="int_atomic_load_and">'<tt>llvm.atomic.load.and.*</tt>' Intrinsic</a><br>
7299 <a name="int_atomic_load_nand">'<tt>llvm.atomic.load.nand.*</tt>' Intrinsic</a><br>
7300 <a name="int_atomic_load_or">'<tt>llvm.atomic.load.or.*</tt>' Intrinsic</a><br>
7301 <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]7302</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7303
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7304<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7305
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7306<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7307<p>These are overloaded intrinsics. You can
7308 use <tt>llvm.atomic.load_and</tt>, <tt>llvm.atomic.load_nand</tt>,
7309 <tt>llvm.atomic.load_or</tt>, and <tt>llvm.atomic.load_xor</tt> on any integer
7310 bit width and for different address spaces. Not all targets support all bit
7311 widths however.</p>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7312
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7313<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7314 declare i8 @llvm.atomic.load.and.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7315 declare i16 @llvm.atomic.load.and.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7316 declare i32 @llvm.atomic.load.and.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7317 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]7318</pre>
7319
7320<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7321 declare i8 @llvm.atomic.load.or.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7322 declare i16 @llvm.atomic.load.or.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7323 declare i32 @llvm.atomic.load.or.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7324 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]7325</pre>
7326
7327<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7328 declare i8 @llvm.atomic.load.nand.i8.p0i32(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7329 declare i16 @llvm.atomic.load.nand.i16.p0i32(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7330 declare i32 @llvm.atomic.load.nand.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7331 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]7332</pre>
7333
7334<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7335 declare i8 @llvm.atomic.load.xor.i8.p0i32(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7336 declare i16 @llvm.atomic.load.xor.i16.p0i32(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7337 declare i32 @llvm.atomic.load.xor.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7338 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]7339</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7340
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7341<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7342<p>These intrinsics bitwise the operation (and, nand, or, xor) <tt>delta</tt> to
7343 the value stored in memory at <tt>ptr</tt>. It yields the original value
7344 at <tt>ptr</tt>.</p>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7345
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7346<h5>Arguments:</h5>
7347<p>These intrinsics take two arguments, the first a pointer to an integer value
7348 and the second an integer value. The result is also an integer value. These
7349 integer types can have any bit width, but they must all have the same bit
7350 width. The targets may only lower integer representations they support.</p>
7351
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7352<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7353<p>These intrinsics does a series of operations atomically. They first load the
7354 value stored at <tt>ptr</tt>. They then do the bitwise
7355 operation <tt>delta</tt>, store the result to <tt>ptr</tt>. They yield the
7356 original value stored at <tt>ptr</tt>.</p>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7357
7358<h5>Examples:</h5>
7359<pre>
Victor Hernandeza70c6df2009-10-26 23:44:29 +0000[diff] [blame]7360%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7361%ptr = bitcast i8* %mallocP to i32*
7362 store i32 0x0F0F, %ptr
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7363%result0 = call i32 @llvm.atomic.load.nand.i32.p0i32(i32* %ptr, i32 0xFF)
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7364 <i>; yields {i32}:result0 = 0x0F0F</i>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7365%result1 = call i32 @llvm.atomic.load.and.i32.p0i32(i32* %ptr, i32 0xFF)
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7366 <i>; yields {i32}:result1 = 0xFFFFFFF0</i>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7367%result2 = call i32 @llvm.atomic.load.or.i32.p0i32(i32* %ptr, i32 0F)
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7368 <i>; yields {i32}:result2 = 0xF0</i>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7369%result3 = call i32 @llvm.atomic.load.xor.i32.p0i32(i32* %ptr, i32 0F)
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7370 <i>; yields {i32}:result3 = FF</i>
7371%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = F0</i>
7372</pre>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7373
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7374</div>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7375
7376<!-- _______________________________________________________________________ -->
7377<div class="doc_subsubsection">
7378 <a name="int_atomic_load_max">'<tt>llvm.atomic.load.max.*</tt>' Intrinsic</a><br>
7379 <a name="int_atomic_load_min">'<tt>llvm.atomic.load.min.*</tt>' Intrinsic</a><br>
7380 <a name="int_atomic_load_umax">'<tt>llvm.atomic.load.umax.*</tt>' Intrinsic</a><br>
7381 <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]7382</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7383
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7384<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7385
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7386<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7387<p>These are overloaded intrinsics. You can use <tt>llvm.atomic.load_max</tt>,
7388 <tt>llvm.atomic.load_min</tt>, <tt>llvm.atomic.load_umax</tt>, and
7389 <tt>llvm.atomic.load_umin</tt> on any integer bit width and for different
7390 address spaces. Not all targets support all bit widths however.</p>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7391
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7392<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7393 declare i8 @llvm.atomic.load.max.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7394 declare i16 @llvm.atomic.load.max.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7395 declare i32 @llvm.atomic.load.max.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7396 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]7397</pre>
7398
7399<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7400 declare i8 @llvm.atomic.load.min.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7401 declare i16 @llvm.atomic.load.min.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7402 declare i32 @llvm.atomic.load.min.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7403 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]7404</pre>
7405
7406<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7407 declare i8 @llvm.atomic.load.umax.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7408 declare i16 @llvm.atomic.load.umax.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7409 declare i32 @llvm.atomic.load.umax.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7410 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]7411</pre>
7412
7413<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7414 declare i8 @llvm.atomic.load.umin.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7415 declare i16 @llvm.atomic.load.umin.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7416 declare i32 @llvm.atomic.load.umin.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7417 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]7418</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7419
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7420<h5>Overview:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]7421<p>These intrinsics takes the signed or unsigned minimum or maximum of
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7422 <tt>delta</tt> and the value stored in memory at <tt>ptr</tt>. It yields the
7423 original value at <tt>ptr</tt>.</p>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7424
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7425<h5>Arguments:</h5>
7426<p>These intrinsics take two arguments, the first a pointer to an integer value
7427 and the second an integer value. The result is also an integer value. These
7428 integer types can have any bit width, but they must all have the same bit
7429 width. The targets may only lower integer representations they support.</p>
7430
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7431<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7432<p>These intrinsics does a series of operations atomically. They first load the
7433 value stored at <tt>ptr</tt>. They then do the signed or unsigned min or
7434 max <tt>delta</tt> and the value, store the result to <tt>ptr</tt>. They
7435 yield the original value stored at <tt>ptr</tt>.</p>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7436
7437<h5>Examples:</h5>
7438<pre>
Victor Hernandeza70c6df2009-10-26 23:44:29 +0000[diff] [blame]7439%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7440%ptr = bitcast i8* %mallocP to i32*
7441 store i32 7, %ptr
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7442%result0 = call i32 @llvm.atomic.load.min.i32.p0i32(i32* %ptr, i32 -2)
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7443 <i>; yields {i32}:result0 = 7</i>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7444%result1 = call i32 @llvm.atomic.load.max.i32.p0i32(i32* %ptr, i32 8)
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7445 <i>; yields {i32}:result1 = -2</i>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7446%result2 = call i32 @llvm.atomic.load.umin.i32.p0i32(i32* %ptr, i32 10)
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7447 <i>; yields {i32}:result2 = 8</i>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7448%result3 = call i32 @llvm.atomic.load.umax.i32.p0i32(i32* %ptr, i32 30)
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7449 <i>; yields {i32}:result3 = 8</i>
7450%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 30</i>
7451</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7452
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7453</div>
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7454
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]7455
7456<!-- ======================================================================= -->
7457<div class="doc_subsection">
7458 <a name="int_memorymarkers">Memory Use Markers</a>
7459</div>
7460
7461<div class="doc_text">
7462
7463<p>This class of intrinsics exists to information about the lifetime of memory
7464 objects and ranges where variables are immutable.</p>
7465
7466</div>
7467
7468<!-- _______________________________________________________________________ -->
7469<div class="doc_subsubsection">
7470 <a name="int_lifetime_start">'<tt>llvm.lifetime.start</tt>' Intrinsic</a>
7471</div>
7472
7473<div class="doc_text">
7474
7475<h5>Syntax:</h5>
7476<pre>
7477 declare void @llvm.lifetime.start(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7478</pre>
7479
7480<h5>Overview:</h5>
7481<p>The '<tt>llvm.lifetime.start</tt>' intrinsic specifies the start of a memory
7482 object's lifetime.</p>
7483
7484<h5>Arguments:</h5>
Nick Lewycky9bc89042009-10-13 07:57:33 +0000[diff] [blame]7485<p>The first argument is a constant integer representing the size of the
7486 object, or -1 if it is variable sized. The second argument is a pointer to
7487 the object.</p>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]7488
7489<h5>Semantics:</h5>
7490<p>This intrinsic indicates that before this point in the code, the value of the
7491 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]7492 never be used and has an undefined value. A load from the pointer that
7493 precedes this intrinsic can be replaced with
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]7494 <tt>'<a href="#undefvalues">undef</a>'</tt>.</p>
7495
7496</div>
7497
7498<!-- _______________________________________________________________________ -->
7499<div class="doc_subsubsection">
7500 <a name="int_lifetime_end">'<tt>llvm.lifetime.end</tt>' Intrinsic</a>
7501</div>
7502
7503<div class="doc_text">
7504
7505<h5>Syntax:</h5>
7506<pre>
7507 declare void @llvm.lifetime.end(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7508</pre>
7509
7510<h5>Overview:</h5>
7511<p>The '<tt>llvm.lifetime.end</tt>' intrinsic specifies the end of a memory
7512 object's lifetime.</p>
7513
7514<h5>Arguments:</h5>
Nick Lewycky9bc89042009-10-13 07:57:33 +0000[diff] [blame]7515<p>The first argument is a constant integer representing the size of the
7516 object, or -1 if it is variable sized. The second argument is a pointer to
7517 the object.</p>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]7518
7519<h5>Semantics:</h5>
7520<p>This intrinsic indicates that after this point in the code, the value of the
7521 memory pointed to by <tt>ptr</tt> is dead. This means that it is known to
7522 never be used and has an undefined value. Any stores into the memory object
7523 following this intrinsic may be removed as dead.
7524
7525</div>
7526
7527<!-- _______________________________________________________________________ -->
7528<div class="doc_subsubsection">
7529 <a name="int_invariant_start">'<tt>llvm.invariant.start</tt>' Intrinsic</a>
7530</div>
7531
7532<div class="doc_text">
7533
7534<h5>Syntax:</h5>
7535<pre>
Nick Lewycky2965d3e2010-11-30 04:13:41 +0000[diff] [blame]7536 declare {}* @llvm.invariant.start(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]7537</pre>
7538
7539<h5>Overview:</h5>
7540<p>The '<tt>llvm.invariant.start</tt>' intrinsic specifies that the contents of
7541 a memory object will not change.</p>
7542
7543<h5>Arguments:</h5>
Nick Lewycky9bc89042009-10-13 07:57:33 +0000[diff] [blame]7544<p>The first argument is a constant integer representing the size of the
7545 object, or -1 if it is variable sized. The second argument is a pointer to
7546 the object.</p>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]7547
7548<h5>Semantics:</h5>
7549<p>This intrinsic indicates that until an <tt>llvm.invariant.end</tt> that uses
7550 the return value, the referenced memory location is constant and
7551 unchanging.</p>
7552
7553</div>
7554
7555<!-- _______________________________________________________________________ -->
7556<div class="doc_subsubsection">
7557 <a name="int_invariant_end">'<tt>llvm.invariant.end</tt>' Intrinsic</a>
7558</div>
7559
7560<div class="doc_text">
7561
7562<h5>Syntax:</h5>
7563<pre>
7564 declare void @llvm.invariant.end({}* &lt;start&gt;, i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7565</pre>
7566
7567<h5>Overview:</h5>
7568<p>The '<tt>llvm.invariant.end</tt>' intrinsic specifies that the contents of
7569 a memory object are mutable.</p>
7570
7571<h5>Arguments:</h5>
7572<p>The first argument is the matching <tt>llvm.invariant.start</tt> intrinsic.
Nick Lewycky9bc89042009-10-13 07:57:33 +0000[diff] [blame]7573 The second argument is a constant integer representing the size of the
7574 object, or -1 if it is variable sized and the third argument is a pointer
7575 to the object.</p>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]7576
7577<h5>Semantics:</h5>
7578<p>This intrinsic indicates that the memory is mutable again.</p>
7579
7580</div>
7581
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7582<!-- ======================================================================= -->
7583<div class="doc_subsection">
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]7584 <a name="int_general">General Intrinsics</a>
7585</div>
7586
7587<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7588
7589<p>This class of intrinsics is designed to be generic and has no specific
7590 purpose.</p>
7591
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]7592</div>
7593
7594<!-- _______________________________________________________________________ -->
7595<div class="doc_subsubsection">
7596 <a name="int_var_annotation">'<tt>llvm.var.annotation</tt>' Intrinsic</a>
7597</div>
7598
7599<div class="doc_text">
7600
7601<h5>Syntax:</h5>
7602<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7603 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]7604</pre>
7605
7606<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7607<p>The '<tt>llvm.var.annotation</tt>' intrinsic.</p>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]7608
7609<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7610<p>The first argument is a pointer to a value, the second is a pointer to a
7611 global string, the third is a pointer to a global string which is the source
7612 file name, and the last argument is the line number.</p>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]7613
7614<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7615<p>This intrinsic allows annotation of local variables with arbitrary strings.
7616 This can be useful for special purpose optimizations that want to look for
7617 these annotations. These have no other defined use, they are ignored by code
7618 generation and optimization.</p>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]7619
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]7620</div>
7621
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]7622<!-- _______________________________________________________________________ -->
7623<div class="doc_subsubsection">
Tanya Lattner0186a652007-09-21 23:57:59 +0000[diff] [blame]7624 <a name="int_annotation">'<tt>llvm.annotation.*</tt>' Intrinsic</a>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]7625</div>
7626
7627<div class="doc_text">
7628
7629<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7630<p>This is an overloaded intrinsic. You can use '<tt>llvm.annotation</tt>' on
7631 any integer bit width.</p>
7632
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]7633<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7634 declare i8 @llvm.annotation.i8(i8 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
7635 declare i16 @llvm.annotation.i16(i16 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
7636 declare i32 @llvm.annotation.i32(i32 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
7637 declare i64 @llvm.annotation.i64(i64 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
7638 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]7639</pre>
7640
7641<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7642<p>The '<tt>llvm.annotation</tt>' intrinsic.</p>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]7643
7644<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7645<p>The first argument is an integer value (result of some expression), the
7646 second is a pointer to a global string, the third is a pointer to a global
7647 string which is the source file name, and the last argument is the line
7648 number. It returns the value of the first argument.</p>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]7649
7650<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7651<p>This intrinsic allows annotations to be put on arbitrary expressions with
7652 arbitrary strings. This can be useful for special purpose optimizations that
7653 want to look for these annotations. These have no other defined use, they
7654 are ignored by code generation and optimization.</p>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]7655
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]7656</div>
Jim Laskey2211f492007-03-14 19:31:19 +0000[diff] [blame]7657
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]7658<!-- _______________________________________________________________________ -->
7659<div class="doc_subsubsection">
7660 <a name="int_trap">'<tt>llvm.trap</tt>' Intrinsic</a>
7661</div>
7662
7663<div class="doc_text">
7664
7665<h5>Syntax:</h5>
7666<pre>
7667 declare void @llvm.trap()
7668</pre>
7669
7670<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7671<p>The '<tt>llvm.trap</tt>' intrinsic.</p>
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]7672
7673<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7674<p>None.</p>
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]7675
7676<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7677<p>This intrinsics is lowered to the target dependent trap instruction. If the
7678 target does not have a trap instruction, this intrinsic will be lowered to
7679 the call of the <tt>abort()</tt> function.</p>
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]7680
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]7681</div>
7682
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]7683<!-- _______________________________________________________________________ -->
7684<div class="doc_subsubsection">
Misha Brukman50de2b22008-11-22 23:55:29 +0000[diff] [blame]7685 <a name="int_stackprotector">'<tt>llvm.stackprotector</tt>' Intrinsic</a>
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]7686</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7687
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]7688<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7689
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]7690<h5>Syntax:</h5>
7691<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7692 declare void @llvm.stackprotector(i8* &lt;guard&gt;, i8** &lt;slot&gt;)
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]7693</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7694
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]7695<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7696<p>The <tt>llvm.stackprotector</tt> intrinsic takes the <tt>guard</tt> and
7697 stores it onto the stack at <tt>slot</tt>. The stack slot is adjusted to
7698 ensure that it is placed on the stack before local variables.</p>
7699
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]7700<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7701<p>The <tt>llvm.stackprotector</tt> intrinsic requires two pointer
7702 arguments. The first argument is the value loaded from the stack
7703 guard <tt>@__stack_chk_guard</tt>. The second variable is an <tt>alloca</tt>
7704 that has enough space to hold the value of the guard.</p>
7705
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]7706<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7707<p>This intrinsic causes the prologue/epilogue inserter to force the position of
7708 the <tt>AllocaInst</tt> stack slot to be before local variables on the
7709 stack. This is to ensure that if a local variable on the stack is
7710 overwritten, it will destroy the value of the guard. When the function exits,
Bill Wendling6bbe0912010-10-27 01:07:41 +0000[diff] [blame]7711 the guard on the stack is checked against the original guard. If they are
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7712 different, then the program aborts by calling the <tt>__stack_chk_fail()</tt>
7713 function.</p>
7714
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]7715</div>
7716
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]7717<!-- _______________________________________________________________________ -->
7718<div class="doc_subsubsection">
7719 <a name="int_objectsize">'<tt>llvm.objectsize</tt>' Intrinsic</a>
7720</div>
7721
7722<div class="doc_text">
7723
7724<h5>Syntax:</h5>
7725<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7726 declare i32 @llvm.objectsize.i32(i8* &lt;object&gt;, i1 &lt;type&gt;)
7727 declare i64 @llvm.objectsize.i64(i8* &lt;object&gt;, i1 &lt;type&gt;)
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]7728</pre>
7729
7730<h5>Overview:</h5>
Bill Wendling6bbe0912010-10-27 01:07:41 +0000[diff] [blame]7731<p>The <tt>llvm.objectsize</tt> intrinsic is designed to provide information to
7732 the optimizers to determine at compile time whether a) an operation (like
7733 memcpy) will overflow a buffer that corresponds to an object, or b) that a
7734 runtime check for overflow isn't necessary. An object in this context means
7735 an allocation of a specific class, structure, array, or other object.</p>
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]7736
7737<h5>Arguments:</h5>
Bill Wendling6bbe0912010-10-27 01:07:41 +0000[diff] [blame]7738<p>The <tt>llvm.objectsize</tt> intrinsic takes two arguments. The first
Eric Christopher31e39bd2009-12-23 00:29:49 +0000[diff] [blame]7739 argument is a pointer to or into the <tt>object</tt>. The second argument
Bill Wendling6bbe0912010-10-27 01:07:41 +0000[diff] [blame]7740 is a boolean 0 or 1. This argument determines whether you want the
7741 maximum (0) or minimum (1) bytes remaining. This needs to be a literal 0 or
Eric Christopher31e39bd2009-12-23 00:29:49 +0000[diff] [blame]7742 1, variables are not allowed.</p>
7743
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]7744<h5>Semantics:</h5>
7745<p>The <tt>llvm.objectsize</tt> intrinsic is lowered to either a constant
Bill Wendling6bbe0912010-10-27 01:07:41 +0000[diff] [blame]7746 representing the size of the object concerned, or <tt>i32/i64 -1 or 0</tt>,
7747 depending on the <tt>type</tt> argument, if the size cannot be determined at
7748 compile time.</p>
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]7749
7750</div>
7751
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]7752<!-- *********************************************************************** -->
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]7753<hr>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]7754<address>
7755 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
Misha Brukman86242e12008-12-11 17:34:48 +0000[diff] [blame]7756 src="http://jigsaw.w3.org/css-validator/images/vcss-blue" alt="Valid CSS"></a>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]7757 <a href="http://validator.w3.org/check/referer"><img
Misha Brukman86242e12008-12-11 17:34:48 +0000[diff] [blame]7758 src="http://www.w3.org/Icons/valid-html401-blue" alt="Valid HTML 4.01"></a>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]7759
7760 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
Reid Spencerca058542006-03-14 05:39:39 +0000[diff] [blame]7761 <a href="http://llvm.org">The LLVM Compiler Infrastructure</a><br>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]7762 Last modified: $Date$
7763</address>
Chris Lattnerb8f816e2008-01-04 04:33:49 +0000[diff] [blame]7764
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]7765</body>
7766</html>