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gerrit-public.fairphone.software / toolchain / llvm-project / fea7ddc735d0f0981c2d8b0d0eeae1dd2ad88770 / . / llvm / docs / LangRef.html
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5 <title>LLVM Assembly Language Reference Manual</title>
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7 <meta name="author" content="Chris Lattner">
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]8 <meta name="description"
Reid Spencercb84e432004-08-26 20:44:00 +0000[diff] [blame]9 content="LLVM Assembly Language Reference Manual.">
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>
3444 &lt;result&gt; = udiv &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3445</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3446
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3447<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3448<p>The '<tt>udiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3449
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3450<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3451<p>The two arguments to the '<tt>udiv</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3452 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3453 values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3454
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3455<h5>Semantics:</h5>
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3456<p>The value produced is the unsigned integer quotient of the two operands.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3457
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3458<p>Note that unsigned integer division and signed integer division are distinct
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3459 operations; for signed integer division, use '<tt>sdiv</tt>'.</p>
3460
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3461<p>Division by zero leads to undefined behavior.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3462
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3463<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3464<pre>
3465 &lt;result&gt; = udiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3466</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3467
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3468</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3469
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3470<!-- _______________________________________________________________________ -->
3471<div class="doc_subsubsection"> <a name="i_sdiv">'<tt>sdiv</tt>' Instruction
3472</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3473
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3474<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3475
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3476<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3477<pre>
Dan Gohmanb07de442009-07-20 22:41:19 +0000[diff] [blame]3478 &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]3479 &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]3480</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3481
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3482<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3483<p>The '<tt>sdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3484
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3485<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3486<p>The two arguments to the '<tt>sdiv</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3487 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3488 values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3489
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3490<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3491<p>The value produced is the signed integer quotient of the two operands rounded
3492 towards zero.</p>
3493
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3494<p>Note that signed integer division and unsigned integer division are distinct
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3495 operations; for unsigned integer division, use '<tt>udiv</tt>'.</p>
3496
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3497<p>Division by zero leads to undefined behavior. Overflow also leads to
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3498 undefined behavior; this is a rare case, but can occur, for example, by doing
3499 a 32-bit division of -2147483648 by -1.</p>
3500
Dan Gohman71dfd782009-07-22 00:04:19 +0000[diff] [blame]3501<p>If the <tt>exact</tt> keyword is present, the result value of the
Dan Gohman57255802010-04-23 15:23:32 +0000[diff] [blame]3502 <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]3503 be rounded.</p>
Dan Gohmanb07de442009-07-20 22:41:19 +0000[diff] [blame]3504
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3505<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3506<pre>
3507 &lt;result&gt; = sdiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3508</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3509
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3510</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3511
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3512<!-- _______________________________________________________________________ -->
3513<div class="doc_subsubsection"> <a name="i_fdiv">'<tt>fdiv</tt>'
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3514Instruction</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3515
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3516<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3517
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3518<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3519<pre>
Gabor Greif0f75ad02008-08-07 21:46:00 +0000[diff] [blame]3520 &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]3521</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3522
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3523<h5>Overview:</h5>
3524<p>The '<tt>fdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3525
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3526<h5>Arguments:</h5>
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]3527<p>The two arguments to the '<tt>fdiv</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3528 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3529 floating point values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3530
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3531<h5>Semantics:</h5>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3532<p>The value produced is the floating point quotient of the two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3533
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3534<h5>Example:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3535<pre>
3536 &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]3537</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3538
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3539</div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3540
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3541<!-- _______________________________________________________________________ -->
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3542<div class="doc_subsubsection"> <a name="i_urem">'<tt>urem</tt>' Instruction</a>
3543</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3544
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3545<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3546
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3547<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3548<pre>
3549 &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]3550</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3551
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3552<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3553<p>The '<tt>urem</tt>' instruction returns the remainder from the unsigned
3554 division of its two arguments.</p>
3555
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3556<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3557<p>The two arguments to the '<tt>urem</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3558 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3559 values. Both arguments must have identical types.</p>
3560
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3561<h5>Semantics:</h5>
3562<p>This instruction returns the unsigned integer <i>remainder</i> of a division.
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3563 This instruction always performs an unsigned division to get the
3564 remainder.</p>
3565
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3566<p>Note that unsigned integer remainder and signed integer remainder are
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3567 distinct operations; for signed integer remainder, use '<tt>srem</tt>'.</p>
3568
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3569<p>Taking the remainder of a division by zero leads to undefined behavior.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3570
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3571<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3572<pre>
3573 &lt;result&gt; = urem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3574</pre>
3575
3576</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3577
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3578<!-- _______________________________________________________________________ -->
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3579<div class="doc_subsubsection">
3580 <a name="i_srem">'<tt>srem</tt>' Instruction</a>
3581</div>
3582
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3583<div class="doc_text">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3584
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3585<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3586<pre>
Gabor Greif0f75ad02008-08-07 21:46:00 +0000[diff] [blame]3587 &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]3588</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3589
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3590<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3591<p>The '<tt>srem</tt>' instruction returns the remainder from the signed
3592 division of its two operands. This instruction can also take
3593 <a href="#t_vector">vector</a> versions of the values in which case the
3594 elements must be integers.</p>
Chris Lattnerb8f816e2008-01-04 04:33:49 +0000[diff] [blame]3595
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3596<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3597<p>The two arguments to the '<tt>srem</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3598 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3599 values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3600
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3601<h5>Semantics:</h5>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3602<p>This instruction returns the <i>remainder</i> of a division (where the result
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3603 has the same sign as the dividend, <tt>op1</tt>), not the <i>modulo</i>
3604 operator (where the result has the same sign as the divisor, <tt>op2</tt>) of
3605 a value. For more information about the difference,
3606 see <a href="http://mathforum.org/dr.math/problems/anne.4.28.99.html">The
3607 Math Forum</a>. For a table of how this is implemented in various languages,
3608 please see <a href="http://en.wikipedia.org/wiki/Modulo_operation">
3609 Wikipedia: modulo operation</a>.</p>
3610
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3611<p>Note that signed integer remainder and unsigned integer remainder are
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3612 distinct operations; for unsigned integer remainder, use '<tt>urem</tt>'.</p>
3613
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3614<p>Taking the remainder of a division by zero leads to undefined behavior.
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3615 Overflow also leads to undefined behavior; this is a rare case, but can
3616 occur, for example, by taking the remainder of a 32-bit division of
3617 -2147483648 by -1. (The remainder doesn't actually overflow, but this rule
3618 lets srem be implemented using instructions that return both the result of
3619 the division and the remainder.)</p>
3620
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3621<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3622<pre>
3623 &lt;result&gt; = srem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3624</pre>
3625
3626</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3627
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3628<!-- _______________________________________________________________________ -->
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3629<div class="doc_subsubsection">
3630 <a name="i_frem">'<tt>frem</tt>' Instruction</a> </div>
3631
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3632<div class="doc_text">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3633
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3634<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3635<pre>
3636 &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]3637</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3638
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3639<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3640<p>The '<tt>frem</tt>' instruction returns the remainder from the division of
3641 its two operands.</p>
3642
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3643<h5>Arguments:</h5>
3644<p>The two arguments to the '<tt>frem</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3645 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3646 floating point values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3647
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3648<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3649<p>This instruction returns the <i>remainder</i> of a division. The remainder
3650 has the same sign as the dividend.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3651
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3652<h5>Example:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3653<pre>
3654 &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]3655</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3656
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3657</div>
Robert Bocchino820bc75b2006-02-17 21:18:08 +0000[diff] [blame]3658
Reid Spencer2ab01932007-02-02 13:57:07 +0000[diff] [blame]3659<!-- ======================================================================= -->
3660<div class="doc_subsection"> <a name="bitwiseops">Bitwise Binary
3661Operations</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3662
Reid Spencer2ab01932007-02-02 13:57:07 +0000[diff] [blame]3663<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3664
3665<p>Bitwise binary operators are used to do various forms of bit-twiddling in a
3666 program. They are generally very efficient instructions and can commonly be
3667 strength reduced from other instructions. They require two operands of the
3668 same type, execute an operation on them, and produce a single value. The
3669 resulting value is the same type as its operands.</p>
3670
Reid Spencer2ab01932007-02-02 13:57:07 +0000[diff] [blame]3671</div>
3672
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3673<!-- _______________________________________________________________________ -->
3674<div class="doc_subsubsection"> <a name="i_shl">'<tt>shl</tt>'
3675Instruction</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3676
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3677<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3678
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3679<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3680<pre>
3681 &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]3682</pre>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]3683
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3684<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3685<p>The '<tt>shl</tt>' instruction returns the first operand shifted to the left
3686 a specified number of bits.</p>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]3687
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3688<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3689<p>Both arguments to the '<tt>shl</tt>' instruction must be the
3690 same <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3691 integer type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3692
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3693<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3694<p>The value produced is <tt>op1</tt> * 2<sup><tt>op2</tt></sup> mod
3695 2<sup>n</sup>, where <tt>n</tt> is the width of the result. If <tt>op2</tt>
3696 is (statically or dynamically) negative or equal to or larger than the number
3697 of bits in <tt>op1</tt>, the result is undefined. If the arguments are
3698 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
3699 shift amount in <tt>op2</tt>.</p>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]3700
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3701<h5>Example:</h5>
3702<pre>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3703 &lt;result&gt; = shl i32 4, %var <i>; yields {i32}: 4 &lt;&lt; %var</i>
3704 &lt;result&gt; = shl i32 4, 2 <i>; yields {i32}: 16</i>
3705 &lt;result&gt; = shl i32 1, 10 <i>; yields {i32}: 1024</i>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]3706 &lt;result&gt; = shl i32 1, 32 <i>; undefined</i>
Mon P Wang4dd832d2008-12-09 05:46:39 +0000[diff] [blame]3707 &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]3708</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3709
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3710</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3711
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3712<!-- _______________________________________________________________________ -->
3713<div class="doc_subsubsection"> <a name="i_lshr">'<tt>lshr</tt>'
3714Instruction</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3715
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3716<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3717
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3718<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3719<pre>
3720 &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]3721</pre>
3722
3723<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3724<p>The '<tt>lshr</tt>' instruction (logical shift right) returns the first
3725 operand shifted to the right a specified number of bits with zero fill.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3726
3727<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3728<p>Both arguments to the '<tt>lshr</tt>' instruction must be the same
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3729 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3730 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3731
3732<h5>Semantics:</h5>
3733<p>This instruction always performs a logical shift right operation. The most
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3734 significant bits of the result will be filled with zero bits after the shift.
3735 If <tt>op2</tt> is (statically or dynamically) equal to or larger than the
3736 number of bits in <tt>op1</tt>, the result is undefined. If the arguments are
3737 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
3738 shift amount in <tt>op2</tt>.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3739
3740<h5>Example:</h5>
3741<pre>
3742 &lt;result&gt; = lshr i32 4, 1 <i>; yields {i32}:result = 2</i>
3743 &lt;result&gt; = lshr i32 4, 2 <i>; yields {i32}:result = 1</i>
3744 &lt;result&gt; = lshr i8 4, 3 <i>; yields {i8}:result = 0</i>
3745 &lt;result&gt; = lshr i8 -2, 1 <i>; yields {i8}:result = 0x7FFFFFFF </i>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]3746 &lt;result&gt; = lshr i32 1, 32 <i>; undefined</i>
Mon P Wang4dd832d2008-12-09 05:46:39 +0000[diff] [blame]3747 &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]3748</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3749
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3750</div>
3751
Reid Spencer2ab01932007-02-02 13:57:07 +0000[diff] [blame]3752<!-- _______________________________________________________________________ -->
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3753<div class="doc_subsubsection"> <a name="i_ashr">'<tt>ashr</tt>'
3754Instruction</a> </div>
3755<div class="doc_text">
3756
3757<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3758<pre>
3759 &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]3760</pre>
3761
3762<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3763<p>The '<tt>ashr</tt>' instruction (arithmetic shift right) returns the first
3764 operand shifted to the right a specified number of bits with sign
3765 extension.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3766
3767<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3768<p>Both arguments to the '<tt>ashr</tt>' instruction must be the same
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3769 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3770 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3771
3772<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3773<p>This instruction always performs an arithmetic shift right operation, The
3774 most significant bits of the result will be filled with the sign bit
3775 of <tt>op1</tt>. If <tt>op2</tt> is (statically or dynamically) equal to or
3776 larger than the number of bits in <tt>op1</tt>, the result is undefined. If
3777 the arguments are vectors, each vector element of <tt>op1</tt> is shifted by
3778 the corresponding shift amount in <tt>op2</tt>.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3779
3780<h5>Example:</h5>
3781<pre>
3782 &lt;result&gt; = ashr i32 4, 1 <i>; yields {i32}:result = 2</i>
3783 &lt;result&gt; = ashr i32 4, 2 <i>; yields {i32}:result = 1</i>
3784 &lt;result&gt; = ashr i8 4, 3 <i>; yields {i8}:result = 0</i>
3785 &lt;result&gt; = ashr i8 -2, 1 <i>; yields {i8}:result = -1</i>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]3786 &lt;result&gt; = ashr i32 1, 32 <i>; undefined</i>
Mon P Wang4dd832d2008-12-09 05:46:39 +0000[diff] [blame]3787 &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]3788</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3789
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3790</div>
3791
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3792<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3793<div class="doc_subsubsection"> <a name="i_and">'<tt>and</tt>'
3794Instruction</a> </div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3795
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3796<div class="doc_text">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3797
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3798<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3799<pre>
Gabor Greif0f75ad02008-08-07 21:46:00 +0000[diff] [blame]3800 &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]3801</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3802
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3803<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3804<p>The '<tt>and</tt>' instruction returns the bitwise logical and of its two
3805 operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3806
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3807<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3808<p>The two arguments to the '<tt>and</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3809 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3810 values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3811
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3812<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3813<p>The truth table used for the '<tt>and</tt>' instruction is:</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3814
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3815<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3816 <tbody>
3817 <tr>
3818 <td>In0</td>
3819 <td>In1</td>
3820 <td>Out</td>
3821 </tr>
3822 <tr>
3823 <td>0</td>
3824 <td>0</td>
3825 <td>0</td>
3826 </tr>
3827 <tr>
3828 <td>0</td>
3829 <td>1</td>
3830 <td>0</td>
3831 </tr>
3832 <tr>
3833 <td>1</td>
3834 <td>0</td>
3835 <td>0</td>
3836 </tr>
3837 <tr>
3838 <td>1</td>
3839 <td>1</td>
3840 <td>1</td>
3841 </tr>
3842 </tbody>
3843</table>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3844
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3845<h5>Example:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3846<pre>
3847 &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]3848 &lt;result&gt; = and i32 15, 40 <i>; yields {i32}:result = 8</i>
3849 &lt;result&gt; = and i32 4, 8 <i>; yields {i32}:result = 0</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3850</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3851</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3852<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3853<div class="doc_subsubsection"> <a name="i_or">'<tt>or</tt>' Instruction</a> </div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3854
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3855<div class="doc_text">
3856
3857<h5>Syntax:</h5>
3858<pre>
3859 &lt;result&gt; = or &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3860</pre>
3861
3862<h5>Overview:</h5>
3863<p>The '<tt>or</tt>' instruction returns the bitwise logical inclusive or of its
3864 two operands.</p>
3865
3866<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3867<p>The two arguments to the '<tt>or</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3868 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3869 values. Both arguments must have identical types.</p>
3870
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3871<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3872<p>The truth table used for the '<tt>or</tt>' instruction is:</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3873
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3874<table border="1" cellspacing="0" cellpadding="4">
3875 <tbody>
3876 <tr>
3877 <td>In0</td>
3878 <td>In1</td>
3879 <td>Out</td>
3880 </tr>
3881 <tr>
3882 <td>0</td>
3883 <td>0</td>
3884 <td>0</td>
3885 </tr>
3886 <tr>
3887 <td>0</td>
3888 <td>1</td>
3889 <td>1</td>
3890 </tr>
3891 <tr>
3892 <td>1</td>
3893 <td>0</td>
3894 <td>1</td>
3895 </tr>
3896 <tr>
3897 <td>1</td>
3898 <td>1</td>
3899 <td>1</td>
3900 </tr>
3901 </tbody>
3902</table>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3903
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3904<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3905<pre>
3906 &lt;result&gt; = or i32 4, %var <i>; yields {i32}:result = 4 | %var</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3907 &lt;result&gt; = or i32 15, 40 <i>; yields {i32}:result = 47</i>
3908 &lt;result&gt; = or i32 4, 8 <i>; yields {i32}:result = 12</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3909</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3910
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3911</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3912
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3913<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3914<div class="doc_subsubsection"> <a name="i_xor">'<tt>xor</tt>'
3915Instruction</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3916
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3917<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3918
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3919<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3920<pre>
3921 &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]3922</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3923
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3924<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3925<p>The '<tt>xor</tt>' instruction returns the bitwise logical exclusive or of
3926 its two operands. The <tt>xor</tt> is used to implement the "one's
3927 complement" operation, which is the "~" operator in C.</p>
3928
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3929<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3930<p>The two arguments to the '<tt>xor</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3931 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3932 values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3933
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3934<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3935<p>The truth table used for the '<tt>xor</tt>' instruction is:</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3936
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3937<table border="1" cellspacing="0" cellpadding="4">
3938 <tbody>
3939 <tr>
3940 <td>In0</td>
3941 <td>In1</td>
3942 <td>Out</td>
3943 </tr>
3944 <tr>
3945 <td>0</td>
3946 <td>0</td>
3947 <td>0</td>
3948 </tr>
3949 <tr>
3950 <td>0</td>
3951 <td>1</td>
3952 <td>1</td>
3953 </tr>
3954 <tr>
3955 <td>1</td>
3956 <td>0</td>
3957 <td>1</td>
3958 </tr>
3959 <tr>
3960 <td>1</td>
3961 <td>1</td>
3962 <td>0</td>
3963 </tr>
3964 </tbody>
3965</table>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3966
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3967<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3968<pre>
3969 &lt;result&gt; = xor i32 4, %var <i>; yields {i32}:result = 4 ^ %var</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3970 &lt;result&gt; = xor i32 15, 40 <i>; yields {i32}:result = 39</i>
3971 &lt;result&gt; = xor i32 4, 8 <i>; yields {i32}:result = 12</i>
3972 &lt;result&gt; = xor i32 %V, -1 <i>; yields {i32}:result = ~%V</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3973</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3974
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3975</div>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3976
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3977<!-- ======================================================================= -->
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3978<div class="doc_subsection">
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]3979 <a name="vectorops">Vector Operations</a>
3980</div>
3981
3982<div class="doc_text">
3983
3984<p>LLVM supports several instructions to represent vector operations in a
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3985 target-independent manner. These instructions cover the element-access and
3986 vector-specific operations needed to process vectors effectively. While LLVM
3987 does directly support these vector operations, many sophisticated algorithms
3988 will want to use target-specific intrinsics to take full advantage of a
3989 specific target.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]3990
3991</div>
3992
3993<!-- _______________________________________________________________________ -->
3994<div class="doc_subsubsection">
3995 <a name="i_extractelement">'<tt>extractelement</tt>' Instruction</a>
3996</div>
3997
3998<div class="doc_text">
3999
4000<h5>Syntax:</h5>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4001<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4002 &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]4003</pre>
4004
4005<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4006<p>The '<tt>extractelement</tt>' instruction extracts a single scalar element
4007 from a vector at a specified index.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4008
4009
4010<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4011<p>The first operand of an '<tt>extractelement</tt>' instruction is a value
4012 of <a href="#t_vector">vector</a> type. The second operand is an index
4013 indicating the position from which to extract the element. The index may be
4014 a variable.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4015
4016<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4017<p>The result is a scalar of the same type as the element type of
4018 <tt>val</tt>. Its value is the value at position <tt>idx</tt> of
4019 <tt>val</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
4020 results are undefined.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4021
4022<h5>Example:</h5>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4023<pre>
Gabor Greif03ab4dc2009-10-28 13:14:50 +0000[diff] [blame]4024 &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]4025</pre>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4026
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4027</div>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4028
4029<!-- _______________________________________________________________________ -->
4030<div class="doc_subsubsection">
4031 <a name="i_insertelement">'<tt>insertelement</tt>' Instruction</a>
4032</div>
4033
4034<div class="doc_text">
4035
4036<h5>Syntax:</h5>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4037<pre>
Dan Gohman43ba0672008-05-12 23:38:42 +0000[diff] [blame]4038 &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]4039</pre>
4040
4041<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4042<p>The '<tt>insertelement</tt>' instruction inserts a scalar element into a
4043 vector at a specified index.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4044
4045<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4046<p>The first operand of an '<tt>insertelement</tt>' instruction is a value
4047 of <a href="#t_vector">vector</a> type. The second operand is a scalar value
4048 whose type must equal the element type of the first operand. The third
4049 operand is an index indicating the position at which to insert the value.
4050 The index may be a variable.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4051
4052<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4053<p>The result is a vector of the same type as <tt>val</tt>. Its element values
4054 are those of <tt>val</tt> except at position <tt>idx</tt>, where it gets the
4055 value <tt>elt</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
4056 results are undefined.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4057
4058<h5>Example:</h5>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4059<pre>
Gabor Greif03ab4dc2009-10-28 13:14:50 +0000[diff] [blame]4060 &lt;result&gt; = 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]4061</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4062
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4063</div>
4064
4065<!-- _______________________________________________________________________ -->
4066<div class="doc_subsubsection">
4067 <a name="i_shufflevector">'<tt>shufflevector</tt>' Instruction</a>
4068</div>
4069
4070<div class="doc_text">
4071
4072<h5>Syntax:</h5>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4073<pre>
Mon P Wang25f01062008-11-10 04:46:22 +0000[diff] [blame]4074 &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]4075</pre>
4076
4077<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4078<p>The '<tt>shufflevector</tt>' instruction constructs a permutation of elements
4079 from two input vectors, returning a vector with the same element type as the
4080 input and length that is the same as the shuffle mask.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4081
4082<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4083<p>The first two operands of a '<tt>shufflevector</tt>' instruction are vectors
4084 with types that match each other. The third argument is a shuffle mask whose
4085 element type is always 'i32'. The result of the instruction is a vector
4086 whose length is the same as the shuffle mask and whose element type is the
4087 same as the element type of the first two operands.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4088
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4089<p>The shuffle mask operand is required to be a constant vector with either
4090 constant integer or undef values.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4091
4092<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4093<p>The elements of the two input vectors are numbered from left to right across
4094 both of the vectors. The shuffle mask operand specifies, for each element of
4095 the result vector, which element of the two input vectors the result element
4096 gets. The element selector may be undef (meaning "don't care") and the
4097 second operand may be undef if performing a shuffle from only one vector.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4098
4099<h5>Example:</h5>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4100<pre>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4101 &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]4102 &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]4103 &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]4104 &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]4105 &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]4106 &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]4107 &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]4108 &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]4109</pre>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4110
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4111</div>
Tanya Lattnerb138bbe2006-04-14 19:24:33 +0000[diff] [blame]4112
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4113<!-- ======================================================================= -->
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4114<div class="doc_subsection">
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4115 <a name="aggregateops">Aggregate Operations</a>
4116</div>
4117
4118<div class="doc_text">
4119
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]4120<p>LLVM supports several instructions for working with
4121 <a href="#t_aggregate">aggregate</a> values.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4122
4123</div>
4124
4125<!-- _______________________________________________________________________ -->
4126<div class="doc_subsubsection">
4127 <a name="i_extractvalue">'<tt>extractvalue</tt>' Instruction</a>
4128</div>
4129
4130<div class="doc_text">
4131
4132<h5>Syntax:</h5>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4133<pre>
4134 &lt;result&gt; = extractvalue &lt;aggregate type&gt; &lt;val&gt;, &lt;idx&gt;{, &lt;idx&gt;}*
4135</pre>
4136
4137<h5>Overview:</h5>
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]4138<p>The '<tt>extractvalue</tt>' instruction extracts the value of a member field
4139 from an <a href="#t_aggregate">aggregate</a> value.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4140
4141<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4142<p>The first operand of an '<tt>extractvalue</tt>' instruction is a value
Chris Lattner13ee7952010-08-28 04:09:24 +0000[diff] [blame]4143 of <a href="#t_struct">struct</a> or
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]4144 <a href="#t_array">array</a> type. The operands are constant indices to
4145 specify which value to extract in a similar manner as indices in a
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4146 '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
Frits van Bommel7cf63ac2010-12-05 20:54:38 +0000[diff] [blame]4147 <p>The major differences to <tt>getelementptr</tt> indexing are:</p>
4148 <ul>
4149 <li>Since the value being indexed is not a pointer, the first index is
4150 omitted and assumed to be zero.</li>
4151 <li>At least one index must be specified.</li>
4152 <li>Not only struct indices but also array indices must be in
4153 bounds.</li>
4154 </ul>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4155
4156<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4157<p>The result is the value at the position in the aggregate specified by the
4158 index operands.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4159
4160<h5>Example:</h5>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4161<pre>
Gabor Greif03ab4dc2009-10-28 13:14:50 +0000[diff] [blame]4162 &lt;result&gt; = extractvalue {i32, float} %agg, 0 <i>; yields i32</i>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4163</pre>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4164
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4165</div>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4166
4167<!-- _______________________________________________________________________ -->
4168<div class="doc_subsubsection">
4169 <a name="i_insertvalue">'<tt>insertvalue</tt>' Instruction</a>
4170</div>
4171
4172<div class="doc_text">
4173
4174<h5>Syntax:</h5>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4175<pre>
Jeffrey Yasskinf991bbb2010-01-11 19:19:26 +0000[diff] [blame]4176 &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]4177</pre>
4178
4179<h5>Overview:</h5>
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]4180<p>The '<tt>insertvalue</tt>' instruction inserts a value into a member field
4181 in an <a href="#t_aggregate">aggregate</a> value.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4182
4183<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4184<p>The first operand of an '<tt>insertvalue</tt>' instruction is a value
Chris Lattner13ee7952010-08-28 04:09:24 +0000[diff] [blame]4185 of <a href="#t_struct">struct</a> or
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]4186 <a href="#t_array">array</a> type. The second operand is a first-class
4187 value to insert. The following operands are constant indices indicating
4188 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]4189 '<tt><a href="#i_extractvalue">extractvalue</a></tt>' instruction. The
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4190 value to insert must have the same type as the value identified by the
4191 indices.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4192
4193<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4194<p>The result is an aggregate of the same type as <tt>val</tt>. Its value is
4195 that of <tt>val</tt> except that the value at the position specified by the
4196 indices is that of <tt>elt</tt>.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4197
4198<h5>Example:</h5>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4199<pre>
Jeffrey Yasskinf991bbb2010-01-11 19:19:26 +0000[diff] [blame]4200 %agg1 = insertvalue {i32, float} undef, i32 1, 0 <i>; yields {i32 1, float undef}</i>
4201 %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]4202</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4203
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4204</div>
4205
4206
4207<!-- ======================================================================= -->
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4208<div class="doc_subsection">
Chris Lattner6ab66722006-08-15 00:45:58 +0000[diff] [blame]4209 <a name="memoryops">Memory Access and Addressing Operations</a>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4210</div>
4211
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4212<div class="doc_text">
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4213
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4214<p>A key design point of an SSA-based representation is how it represents
4215 memory. In LLVM, no memory locations are in SSA form, which makes things
Victor Hernandeza70c6df2009-10-26 23:44:29 +0000[diff] [blame]4216 very simple. This section describes how to read, write, and allocate
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4217 memory in LLVM.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4218
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4219</div>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4220
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4221<!-- _______________________________________________________________________ -->
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4222<div class="doc_subsubsection">
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4223 <a name="i_alloca">'<tt>alloca</tt>' Instruction</a>
4224</div>
4225
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4226<div class="doc_text">
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4227
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4228<h5>Syntax:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4229<pre>
Dan Gohman2140a742010-05-28 01:14:11 +0000[diff] [blame]4230 &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]4231</pre>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4232
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4233<h5>Overview:</h5>
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]4234<p>The '<tt>alloca</tt>' instruction allocates memory on the stack frame of the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4235 currently executing function, to be automatically released when this function
4236 returns to its caller. The object is always allocated in the generic address
4237 space (address space zero).</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4238
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4239<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4240<p>The '<tt>alloca</tt>' instruction
4241 allocates <tt>sizeof(&lt;type&gt;)*NumElements</tt> bytes of memory on the
4242 runtime stack, returning a pointer of the appropriate type to the program.
4243 If "NumElements" is specified, it is the number of elements allocated,
4244 otherwise "NumElements" is defaulted to be one. If a constant alignment is
4245 specified, the value result of the allocation is guaranteed to be aligned to
4246 at least that boundary. If not specified, or if zero, the target can choose
4247 to align the allocation on any convenient boundary compatible with the
4248 type.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4249
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4250<p>'<tt>type</tt>' may be any sized type.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4251
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4252<h5>Semantics:</h5>
Bill Wendling9ee6a312009-05-08 20:49:29 +0000[diff] [blame]4253<p>Memory is allocated; a pointer is returned. The operation is undefined if
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4254 there is insufficient stack space for the allocation. '<tt>alloca</tt>'d
4255 memory is automatically released when the function returns. The
4256 '<tt>alloca</tt>' instruction is commonly used to represent automatic
4257 variables that must have an address available. When the function returns
4258 (either with the <tt><a href="#i_ret">ret</a></tt>
4259 or <tt><a href="#i_unwind">unwind</a></tt> instructions), the memory is
4260 reclaimed. Allocating zero bytes is legal, but the result is undefined.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4261
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4262<h5>Example:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4263<pre>
Dan Gohman7a5acb52009-01-04 23:49:44 +0000[diff] [blame]4264 %ptr = alloca i32 <i>; yields {i32*}:ptr</i>
4265 %ptr = alloca i32, i32 4 <i>; yields {i32*}:ptr</i>
4266 %ptr = alloca i32, i32 4, align 1024 <i>; yields {i32*}:ptr</i>
4267 %ptr = alloca i32, align 1024 <i>; yields {i32*}:ptr</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4268</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4269
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4270</div>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4271
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4272<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]4273<div class="doc_subsubsection"> <a name="i_load">'<tt>load</tt>'
4274Instruction</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4275
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4276<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4277
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4278<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4279<pre>
Bill Wendlingbc4024f2010-02-25 21:23:24 +0000[diff] [blame]4280 &lt;result&gt; = load &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;][, !nontemporal !&lt;index&gt;]
4281 &lt;result&gt; = volatile load &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;][, !nontemporal !&lt;index&gt;]
4282 !&lt;index&gt; = !{ i32 1 }
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4283</pre>
4284
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4285<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4286<p>The '<tt>load</tt>' instruction is used to read from memory.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4287
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4288<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4289<p>The argument to the '<tt>load</tt>' instruction specifies the memory address
4290 from which to load. The pointer must point to
4291 a <a href="#t_firstclass">first class</a> type. If the <tt>load</tt> is
4292 marked as <tt>volatile</tt>, then the optimizer is not allowed to modify the
Jeffrey Yasskin5d284ae2010-04-26 21:21:24 +0000[diff] [blame]4293 number or order of execution of this <tt>load</tt> with other <a
4294 href="#volatile">volatile operations</a>.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4295
Bill Wendlingbc4024f2010-02-25 21:23:24 +0000[diff] [blame]4296<p>The optional constant <tt>align</tt> argument specifies the alignment of the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4297 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]4298 omitted <tt>align</tt> argument means that the operation has the preferential
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4299 alignment for the target. It is the responsibility of the code emitter to
4300 ensure that the alignment information is correct. Overestimating the
Bill Wendlingbc4024f2010-02-25 21:23:24 +0000[diff] [blame]4301 alignment results in undefined behavior. Underestimating the alignment may
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4302 produce less efficient code. An alignment of 1 is always safe.</p>
4303
Bill Wendlingbc4024f2010-02-25 21:23:24 +0000[diff] [blame]4304<p>The optional <tt>!nontemporal</tt> metadata must reference a single
4305 metatadata name &lt;index&gt; corresponding to a metadata node with
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]4306 one <tt>i32</tt> entry of value 1. The existence of
Bill Wendlingbc4024f2010-02-25 21:23:24 +0000[diff] [blame]4307 the <tt>!nontemporal</tt> metatadata on the instruction tells the optimizer
4308 and code generator that this load is not expected to be reused in the cache.
4309 The code generator may select special instructions to save cache bandwidth,
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]4310 such as the <tt>MOVNT</tt> instruction on x86.</p>
David Greene9641d062010-02-16 20:50:18 +0000[diff] [blame]4311
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4312<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4313<p>The location of memory pointed to is loaded. If the value being loaded is of
4314 scalar type then the number of bytes read does not exceed the minimum number
4315 of bytes needed to hold all bits of the type. For example, loading an
4316 <tt>i24</tt> reads at most three bytes. When loading a value of a type like
4317 <tt>i20</tt> with a size that is not an integral number of bytes, the result
4318 is undefined if the value was not originally written using a store of the
4319 same type.</p>
4320
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4321<h5>Examples:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4322<pre>
4323 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
4324 <a href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4325 %val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4326</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4327
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4328</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4329
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4330<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]4331<div class="doc_subsubsection"> <a name="i_store">'<tt>store</tt>'
4332Instruction</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4333
Reid Spencera89fb182006-11-09 21:18:01 +0000[diff] [blame]4334<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4335
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4336<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4337<pre>
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]4338 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>
4339 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]4340</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4341
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4342<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4343<p>The '<tt>store</tt>' instruction is used to write to memory.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4344
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4345<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4346<p>There are two arguments to the '<tt>store</tt>' instruction: a value to store
4347 and an address at which to store it. The type of the
4348 '<tt>&lt;pointer&gt;</tt>' operand must be a pointer to
4349 the <a href="#t_firstclass">first class</a> type of the
Jeffrey Yasskin5d284ae2010-04-26 21:21:24 +0000[diff] [blame]4350 '<tt>&lt;value&gt;</tt>' operand. If the <tt>store</tt> is marked as
4351 <tt>volatile</tt>, then the optimizer is not allowed to modify the number or
4352 order of execution of this <tt>store</tt> with other <a
4353 href="#volatile">volatile operations</a>.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4354
4355<p>The optional constant "align" argument specifies the alignment of the
4356 operation (that is, the alignment of the memory address). A value of 0 or an
4357 omitted "align" argument means that the operation has the preferential
4358 alignment for the target. It is the responsibility of the code emitter to
4359 ensure that the alignment information is correct. Overestimating the
4360 alignment results in an undefined behavior. Underestimating the alignment may
4361 produce less efficient code. An alignment of 1 is always safe.</p>
4362
David Greene9641d062010-02-16 20:50:18 +0000[diff] [blame]4363<p>The optional !nontemporal metadata must reference a single metatadata
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]4364 name &lt;index&gt; corresponding to a metadata node with one i32 entry of
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]4365 value 1. The existence of the !nontemporal metatadata on the
David Greene9641d062010-02-16 20:50:18 +0000[diff] [blame]4366 instruction tells the optimizer and code generator that this load is
4367 not expected to be reused in the cache. The code generator may
4368 select special instructions to save cache bandwidth, such as the
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]4369 MOVNT instruction on x86.</p>
David Greene9641d062010-02-16 20:50:18 +0000[diff] [blame]4370
4371
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]4372<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4373<p>The contents of memory are updated to contain '<tt>&lt;value&gt;</tt>' at the
4374 location specified by the '<tt>&lt;pointer&gt;</tt>' operand. If
4375 '<tt>&lt;value&gt;</tt>' is of scalar type then the number of bytes written
4376 does not exceed the minimum number of bytes needed to hold all bits of the
4377 type. For example, storing an <tt>i24</tt> writes at most three bytes. When
4378 writing a value of a type like <tt>i20</tt> with a size that is not an
4379 integral number of bytes, it is unspecified what happens to the extra bits
4380 that do not belong to the type, but they will typically be overwritten.</p>
4381
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4382<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4383<pre>
4384 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Bill Wendling8830ffe2007-10-22 05:10:05 +0000[diff] [blame]4385 store i32 3, i32* %ptr <i>; yields {void}</i>
4386 %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]4387</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4388
Reid Spencer443460a2006-11-09 21:15:49 +0000[diff] [blame]4389</div>
4390
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4391<!-- _______________________________________________________________________ -->
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4392<div class="doc_subsubsection">
4393 <a name="i_getelementptr">'<tt>getelementptr</tt>' Instruction</a>
4394</div>
4395
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4396<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4397
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]4398<h5>Syntax:</h5>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4399<pre>
Matthijs Kooijman0e268272008-10-13 13:44:15 +0000[diff] [blame]4400 &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]4401 &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]4402</pre>
4403
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]4404<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4405<p>The '<tt>getelementptr</tt>' instruction is used to get the address of a
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]4406 subelement of an <a href="#t_aggregate">aggregate</a> data structure.
4407 It performs address calculation only and does not access memory.</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4408
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]4409<h5>Arguments:</h5>
Matthijs Kooijman0e268272008-10-13 13:44:15 +0000[diff] [blame]4410<p>The first argument is always a pointer, and forms the basis of the
Chris Lattnera40b9122009-07-29 06:44:13 +0000[diff] [blame]4411 calculation. The remaining arguments are indices that indicate which of the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4412 elements of the aggregate object are indexed. The interpretation of each
4413 index is dependent on the type being indexed into. The first index always
4414 indexes the pointer value given as the first argument, the second index
4415 indexes a value of the type pointed to (not necessarily the value directly
4416 pointed to, since the first index can be non-zero), etc. The first type
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]4417 indexed into must be a pointer value, subsequent types can be arrays,
Chris Lattner13ee7952010-08-28 04:09:24 +0000[diff] [blame]4418 vectors, and structs. Note that subsequent types being indexed into
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]4419 can never be pointers, since that would require loading the pointer before
4420 continuing calculation.</p>
Matthijs Kooijman0e268272008-10-13 13:44:15 +0000[diff] [blame]4421
4422<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]4423 When indexing into a (optionally packed) structure, only <tt>i32</tt>
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]4424 integer <b>constants</b> are allowed. When indexing into an array, pointer
4425 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]4426 constant.</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4427
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4428<p>For example, let's consider a C code fragment and how it gets compiled to
4429 LLVM:</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4430
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]4431<pre class="doc_code">
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]4432struct RT {
4433 char A;
Chris Lattnera446f1b2007-05-29 15:43:56 +0000[diff] [blame]4434 int B[10][20];
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]4435 char C;
4436};
4437struct ST {
Chris Lattnera446f1b2007-05-29 15:43:56 +0000[diff] [blame]4438 int X;
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]4439 double Y;
4440 struct RT Z;
4441};
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4442
Chris Lattnera446f1b2007-05-29 15:43:56 +0000[diff] [blame]4443int *foo(struct ST *s) {
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]4444 return &amp;s[1].Z.B[5][13];
4445}
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4446</pre>
4447
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4448<p>The LLVM code generated by the GCC frontend is:</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4449
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]4450<pre class="doc_code">
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]4451%RT = <a href="#namedtypes">type</a> { i8 , [10 x [20 x i32]], i8 }
4452%ST = <a href="#namedtypes">type</a> { i32, double, %RT }
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4453
Dan Gohman6b867702009-07-25 02:23:48 +0000[diff] [blame]4454define i32* @foo(%ST* %s) {
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]4455entry:
4456 %reg = getelementptr %ST* %s, i32 1, i32 2, i32 1, i32 5, i32 13
4457 ret i32* %reg
4458}
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4459</pre>
4460
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]4461<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4462<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]4463 type, which is a pointer, yielding a '<tt>%ST</tt>' = '<tt>{ i32, double, %RT
4464 }</tt>' type, a structure. The second index indexes into the third element
4465 of the structure, yielding a '<tt>%RT</tt>' = '<tt>{ i8 , [10 x [20 x i32]],
4466 i8 }</tt>' type, another structure. The third index indexes into the second
4467 element of the structure, yielding a '<tt>[10 x [20 x i32]]</tt>' type, an
4468 array. The two dimensions of the array are subscripted into, yielding an
4469 '<tt>i32</tt>' type. The '<tt>getelementptr</tt>' instruction returns a
4470 pointer to this element, thus computing a value of '<tt>i32*</tt>' type.</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4471
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4472<p>Note that it is perfectly legal to index partially through a structure,
4473 returning a pointer to an inner element. Because of this, the LLVM code for
4474 the given testcase is equivalent to:</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4475
4476<pre>
Dan Gohman6b867702009-07-25 02:23:48 +0000[diff] [blame]4477 define i32* @foo(%ST* %s) {
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4478 %t1 = getelementptr %ST* %s, i32 1 <i>; yields %ST*:%t1</i>
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]4479 %t2 = getelementptr %ST* %t1, i32 0, i32 2 <i>; yields %RT*:%t2</i>
4480 %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]4481 %t4 = getelementptr [10 x [20 x i32]]* %t3, i32 0, i32 5 <i>; yields [20 x i32]*:%t4</i>
4482 %t5 = getelementptr [20 x i32]* %t4, i32 0, i32 13 <i>; yields i32*:%t5</i>
4483 ret i32* %t5
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4484 }
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]4485</pre>
Chris Lattnerc0ad71e2005-06-24 17:22:57 +0000[diff] [blame]4486
Dan Gohman1639c392009-07-27 21:53:46 +0000[diff] [blame]4487<p>If the <tt>inbounds</tt> keyword is present, the result value of the
Dan Gohman57255802010-04-23 15:23:32 +0000[diff] [blame]4488 <tt>getelementptr</tt> is a <a href="#trapvalues">trap value</a> if the
4489 base pointer is not an <i>in bounds</i> address of an allocated object,
4490 or if any of the addresses that would be formed by successive addition of
4491 the offsets implied by the indices to the base address with infinitely
4492 precise arithmetic are not an <i>in bounds</i> address of that allocated
4493 object. The <i>in bounds</i> addresses for an allocated object are all
4494 the addresses that point into the object, plus the address one byte past
4495 the end.</p>
Dan Gohman1639c392009-07-27 21:53:46 +0000[diff] [blame]4496
4497<p>If the <tt>inbounds</tt> keyword is not present, the offsets are added to
4498 the base address with silently-wrapping two's complement arithmetic, and
4499 the result value of the <tt>getelementptr</tt> may be outside the object
4500 pointed to by the base pointer. The result value may not necessarily be
4501 used to access memory though, even if it happens to point into allocated
4502 storage. See the <a href="#pointeraliasing">Pointer Aliasing Rules</a>
4503 section for more information.</p>
4504
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4505<p>The getelementptr instruction is often confusing. For some more insight into
4506 how it works, see <a href="GetElementPtr.html">the getelementptr FAQ</a>.</p>
Chris Lattner6ab66722006-08-15 00:45:58 +0000[diff] [blame]4507
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]4508<h5>Example:</h5>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4509<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4510 <i>; yields [12 x i8]*:aptr</i>
Matthijs Kooijman0e268272008-10-13 13:44:15 +0000[diff] [blame]4511 %aptr = getelementptr {i32, [12 x i8]}* %saptr, i64 0, i32 1
4512 <i>; yields i8*:vptr</i>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]4513 %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]4514 <i>; yields i8*:eptr</i>
4515 %eptr = getelementptr [12 x i8]* %aptr, i64 0, i32 1
Sanjiv Gupta0c155e62009-04-25 07:27:44 +0000[diff] [blame]4516 <i>; yields i32*:iptr</i>
Sanjiv Gupta77abea02009-04-24 16:38:13 +0000[diff] [blame]4517 %iptr = getelementptr [10 x i32]* @arr, i16 0, i16 0
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4518</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4519
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4520</div>
Reid Spencer443460a2006-11-09 21:15:49 +0000[diff] [blame]4521
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4522<!-- ======================================================================= -->
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]4523<div class="doc_subsection"> <a name="convertops">Conversion Operations</a>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4524</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4525
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4526<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4527
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]4528<p>The instructions in this category are the conversion instructions (casting)
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4529 which all take a single operand and a type. They perform various bit
4530 conversions on the operand.</p>
4531
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4532</div>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]4533
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]4534<!-- _______________________________________________________________________ -->
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]4535<div class="doc_subsubsection">
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4536 <a name="i_trunc">'<tt>trunc .. to</tt>' Instruction</a>
4537</div>
4538<div class="doc_text">
4539
4540<h5>Syntax:</h5>
4541<pre>
4542 &lt;result&gt; = trunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4543</pre>
4544
4545<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4546<p>The '<tt>trunc</tt>' instruction truncates its operand to the
4547 type <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4548
4549<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4550<p>The '<tt>trunc</tt>' instruction takes a <tt>value</tt> to trunc, which must
4551 be an <a href="#t_integer">integer</a> type, and a type that specifies the
4552 size and type of the result, which must be
4553 an <a href="#t_integer">integer</a> type. The bit size of <tt>value</tt> must
4554 be larger than the bit size of <tt>ty2</tt>. Equal sized types are not
4555 allowed.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4556
4557<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4558<p>The '<tt>trunc</tt>' instruction truncates the high order bits
4559 in <tt>value</tt> and converts the remaining bits to <tt>ty2</tt>. Since the
4560 source size must be larger than the destination size, <tt>trunc</tt> cannot
4561 be a <i>no-op cast</i>. It will always truncate bits.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4562
4563<h5>Example:</h5>
4564<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4565 %X = trunc i32 257 to i8 <i>; yields i8:1</i>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]4566 %Y = trunc i32 123 to i1 <i>; yields i1:true</i>
Gabor Greiff50fd572009-10-28 09:21:30 +0000[diff] [blame]4567 %Z = trunc i32 122 to i1 <i>; yields i1:false</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4568</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4569
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4570</div>
4571
4572<!-- _______________________________________________________________________ -->
4573<div class="doc_subsubsection">
4574 <a name="i_zext">'<tt>zext .. to</tt>' Instruction</a>
4575</div>
4576<div class="doc_text">
4577
4578<h5>Syntax:</h5>
4579<pre>
4580 &lt;result&gt; = zext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4581</pre>
4582
4583<h5>Overview:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4584<p>The '<tt>zext</tt>' instruction zero extends its operand to type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4585 <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4586
4587
4588<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4589<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]4590 <a href="#t_integer">integer</a> type, and a type to cast it to, which must
4591 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]4592 <tt>value</tt> must be smaller than the bit size of the destination type,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4593 <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4594
4595<h5>Semantics:</h5>
4596<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]4597 bits until it reaches the size of the destination type, <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4598
Reid Spencer07c9c682007-01-12 15:46:11 +0000[diff] [blame]4599<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]4600
4601<h5>Example:</h5>
4602<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4603 %X = zext i32 257 to i64 <i>; yields i64:257</i>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]4604 %Y = zext i1 true to i32 <i>; yields i32:1</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4605</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4606
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4607</div>
4608
4609<!-- _______________________________________________________________________ -->
4610<div class="doc_subsubsection">
4611 <a name="i_sext">'<tt>sext .. to</tt>' Instruction</a>
4612</div>
4613<div class="doc_text">
4614
4615<h5>Syntax:</h5>
4616<pre>
4617 &lt;result&gt; = sext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4618</pre>
4619
4620<h5>Overview:</h5>
4621<p>The '<tt>sext</tt>' sign extends <tt>value</tt> to the type <tt>ty2</tt>.</p>
4622
4623<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4624<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]4625 <a href="#t_integer">integer</a> type, and a type to cast it to, which must
4626 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]4627 <tt>value</tt> must be smaller than the bit size of the destination type,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4628 <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4629
4630<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4631<p>The '<tt>sext</tt>' instruction performs a sign extension by copying the sign
4632 bit (highest order bit) of the <tt>value</tt> until it reaches the bit size
4633 of the type <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4634
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]4635<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]4636
4637<h5>Example:</h5>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4638<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4639 %X = sext i8 -1 to i16 <i>; yields i16 :65535</i>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]4640 %Y = sext i1 true to i32 <i>; yields i32:-1</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4641</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4642
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4643</div>
4644
4645<!-- _______________________________________________________________________ -->
4646<div class="doc_subsubsection">
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]4647 <a name="i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a>
4648</div>
4649
4650<div class="doc_text">
4651
4652<h5>Syntax:</h5>
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]4653<pre>
4654 &lt;result&gt; = fptrunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4655</pre>
4656
4657<h5>Overview:</h5>
4658<p>The '<tt>fptrunc</tt>' instruction truncates <tt>value</tt> to type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4659 <tt>ty2</tt>.</p>
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]4660
4661<h5>Arguments:</h5>
4662<p>The '<tt>fptrunc</tt>' instruction takes a <a href="#t_floating">floating
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4663 point</a> value to cast and a <a href="#t_floating">floating point</a> type
4664 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]4665 <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]4666 <i>no-op cast</i>.</p>
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]4667
4668<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4669<p>The '<tt>fptrunc</tt>' instruction truncates a <tt>value</tt> from a larger
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4670 <a href="#t_floating">floating point</a> type to a smaller
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4671 <a href="#t_floating">floating point</a> type. If the value cannot fit
4672 within the destination type, <tt>ty2</tt>, then the results are
4673 undefined.</p>
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]4674
4675<h5>Example:</h5>
4676<pre>
4677 %X = fptrunc double 123.0 to float <i>; yields float:123.0</i>
4678 %Y = fptrunc double 1.0E+300 to float <i>; yields undefined</i>
4679</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4680
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]4681</div>
4682
4683<!-- _______________________________________________________________________ -->
4684<div class="doc_subsubsection">
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4685 <a name="i_fpext">'<tt>fpext .. to</tt>' Instruction</a>
4686</div>
4687<div class="doc_text">
4688
4689<h5>Syntax:</h5>
4690<pre>
4691 &lt;result&gt; = fpext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4692</pre>
4693
4694<h5>Overview:</h5>
4695<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]4696 floating point value.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4697
4698<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4699<p>The '<tt>fpext</tt>' instruction takes a
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4700 <a href="#t_floating">floating point</a> <tt>value</tt> to cast, and
4701 a <a href="#t_floating">floating point</a> type to cast it to. The source
4702 type must be smaller than the destination type.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4703
4704<h5>Semantics:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]4705<p>The '<tt>fpext</tt>' instruction extends the <tt>value</tt> from a smaller
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4706 <a href="#t_floating">floating point</a> type to a larger
4707 <a href="#t_floating">floating point</a> type. The <tt>fpext</tt> cannot be
4708 used to make a <i>no-op cast</i> because it always changes bits. Use
4709 <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]4710
4711<h5>Example:</h5>
4712<pre>
4713 %X = fpext float 3.1415 to double <i>; yields double:3.1415</i>
4714 %Y = fpext float 1.0 to float <i>; yields float:1.0 (no-op)</i>
4715</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4716
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4717</div>
4718
4719<!-- _______________________________________________________________________ -->
4720<div class="doc_subsubsection">
Reid Spencer2eadb532007-01-21 00:29:26 +0000[diff] [blame]4721 <a name="i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4722</div>
4723<div class="doc_text">
4724
4725<h5>Syntax:</h5>
4726<pre>
Reid Spencer753163d2007-07-31 14:40:14 +0000[diff] [blame]4727 &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]4728</pre>
4729
4730<h5>Overview:</h5>
Reid Spencer753163d2007-07-31 14:40:14 +0000[diff] [blame]4731<p>The '<tt>fptoui</tt>' converts a floating point <tt>value</tt> to its
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4732 unsigned integer equivalent of type <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4733
4734<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4735<p>The '<tt>fptoui</tt>' instruction takes a value to cast, which must be a
4736 scalar or vector <a href="#t_floating">floating point</a> value, and a type
4737 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
4738 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
4739 vector integer type with the same number of elements as <tt>ty</tt></p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4740
4741<h5>Semantics:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4742<p>The '<tt>fptoui</tt>' instruction converts its
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4743 <a href="#t_floating">floating point</a> operand into the nearest (rounding
4744 towards zero) unsigned integer value. If the value cannot fit
4745 in <tt>ty2</tt>, the results are undefined.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4746
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4747<h5>Example:</h5>
4748<pre>
Reid Spencer753163d2007-07-31 14:40:14 +0000[diff] [blame]4749 %X = fptoui double 123.0 to i32 <i>; yields i32:123</i>
Chris Lattner5b95a172007-09-22 03:17:52 +0000[diff] [blame]4750 %Y = fptoui float 1.0E+300 to i1 <i>; yields undefined:1</i>
Gabor Greiff50fd572009-10-28 09:21:30 +0000[diff] [blame]4751 %Z = fptoui float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4752</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4753
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4754</div>
4755
4756<!-- _______________________________________________________________________ -->
4757<div class="doc_subsubsection">
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]4758 <a name="i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4759</div>
4760<div class="doc_text">
4761
4762<h5>Syntax:</h5>
4763<pre>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]4764 &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]4765</pre>
4766
4767<h5>Overview:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4768<p>The '<tt>fptosi</tt>' instruction converts
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4769 <a href="#t_floating">floating point</a> <tt>value</tt> to
4770 type <tt>ty2</tt>.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]4771
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]4772<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4773<p>The '<tt>fptosi</tt>' instruction takes a value to cast, which must be a
4774 scalar or vector <a href="#t_floating">floating point</a> value, and a type
4775 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
4776 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
4777 vector integer type with the same number of elements as <tt>ty</tt></p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]4778
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]4779<h5>Semantics:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4780<p>The '<tt>fptosi</tt>' instruction converts its
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4781 <a href="#t_floating">floating point</a> operand into the nearest (rounding
4782 towards zero) signed integer value. If the value cannot fit in <tt>ty2</tt>,
4783 the results are undefined.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]4784
Chris Lattner70de6632001-07-09 00:26:23 +0000[diff] [blame]4785<h5>Example:</h5>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]4786<pre>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]4787 %X = fptosi double -123.0 to i32 <i>; yields i32:-123</i>
Chris Lattner5b95a172007-09-22 03:17:52 +0000[diff] [blame]4788 %Y = fptosi float 1.0E-247 to i1 <i>; yields undefined:1</i>
Gabor Greiff50fd572009-10-28 09:21:30 +0000[diff] [blame]4789 %Z = fptosi float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4790</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4791
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4792</div>
4793
4794<!-- _______________________________________________________________________ -->
4795<div class="doc_subsubsection">
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]4796 <a name="i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4797</div>
4798<div class="doc_text">
4799
4800<h5>Syntax:</h5>
4801<pre>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]4802 &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]4803</pre>
4804
4805<h5>Overview:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]4806<p>The '<tt>uitofp</tt>' instruction regards <tt>value</tt> as an unsigned
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4807 integer and converts that value to the <tt>ty2</tt> type.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4808
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4809<h5>Arguments:</h5>
Nate Begemand4d45c22007-11-17 03:58:34 +0000[diff] [blame]4810<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]4811 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
4812 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
4813 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
4814 floating point type with the same number of elements as <tt>ty</tt></p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4815
4816<h5>Semantics:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]4817<p>The '<tt>uitofp</tt>' instruction interprets its operand as an unsigned
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4818 integer quantity and converts it to the corresponding floating point
4819 value. If the value cannot fit in the floating point value, the results are
4820 undefined.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4821
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4822<h5>Example:</h5>
4823<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4824 %X = uitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]4825 %Y = uitofp i8 -1 to double <i>; yields double:255.0</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4826</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4827
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4828</div>
4829
4830<!-- _______________________________________________________________________ -->
4831<div class="doc_subsubsection">
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]4832 <a name="i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4833</div>
4834<div class="doc_text">
4835
4836<h5>Syntax:</h5>
4837<pre>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]4838 &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]4839</pre>
4840
4841<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4842<p>The '<tt>sitofp</tt>' instruction regards <tt>value</tt> as a signed integer
4843 and converts that value to the <tt>ty2</tt> type.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4844
4845<h5>Arguments:</h5>
Nate Begemand4d45c22007-11-17 03:58:34 +0000[diff] [blame]4846<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]4847 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
4848 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
4849 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
4850 floating point type with the same number of elements as <tt>ty</tt></p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4851
4852<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4853<p>The '<tt>sitofp</tt>' instruction interprets its operand as a signed integer
4854 quantity and converts it to the corresponding floating point value. If the
4855 value cannot fit in the floating point value, the results are undefined.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4856
4857<h5>Example:</h5>
4858<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4859 %X = sitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]4860 %Y = sitofp i8 -1 to double <i>; yields double:-1.0</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4861</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4862
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4863</div>
4864
4865<!-- _______________________________________________________________________ -->
4866<div class="doc_subsubsection">
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]4867 <a name="i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a>
4868</div>
4869<div class="doc_text">
4870
4871<h5>Syntax:</h5>
4872<pre>
4873 &lt;result&gt; = ptrtoint &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4874</pre>
4875
4876<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4877<p>The '<tt>ptrtoint</tt>' instruction converts the pointer <tt>value</tt> to
4878 the integer type <tt>ty2</tt>.</p>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]4879
4880<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4881<p>The '<tt>ptrtoint</tt>' instruction takes a <tt>value</tt> to cast, which
4882 must be a <a href="#t_pointer">pointer</a> value, and a type to cast it to
4883 <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]4884
4885<h5>Semantics:</h5>
4886<p>The '<tt>ptrtoint</tt>' instruction converts <tt>value</tt> to integer type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4887 <tt>ty2</tt> by interpreting the pointer value as an integer and either
4888 truncating or zero extending that value to the size of the integer type. If
4889 <tt>value</tt> is smaller than <tt>ty2</tt> then a zero extension is done. If
4890 <tt>value</tt> is larger than <tt>ty2</tt> then a truncation is done. If they
4891 are the same size, then nothing is done (<i>no-op cast</i>) other than a type
4892 change.</p>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]4893
4894<h5>Example:</h5>
4895<pre>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]4896 %X = ptrtoint i32* %X to i8 <i>; yields truncation on 32-bit architecture</i>
4897 %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]4898</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4899
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]4900</div>
4901
4902<!-- _______________________________________________________________________ -->
4903<div class="doc_subsubsection">
4904 <a name="i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a>
4905</div>
4906<div class="doc_text">
4907
4908<h5>Syntax:</h5>
4909<pre>
4910 &lt;result&gt; = inttoptr &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4911</pre>
4912
4913<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4914<p>The '<tt>inttoptr</tt>' instruction converts an integer <tt>value</tt> to a
4915 pointer type, <tt>ty2</tt>.</p>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]4916
4917<h5>Arguments:</h5>
Duncan Sands16f122e2007-03-30 12:22:09 +0000[diff] [blame]4918<p>The '<tt>inttoptr</tt>' instruction takes an <a href="#t_integer">integer</a>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4919 value to cast, and a type to cast it to, which must be a
4920 <a href="#t_pointer">pointer</a> type.</p>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]4921
4922<h5>Semantics:</h5>
4923<p>The '<tt>inttoptr</tt>' instruction converts <tt>value</tt> to type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4924 <tt>ty2</tt> by applying either a zero extension or a truncation depending on
4925 the size of the integer <tt>value</tt>. If <tt>value</tt> is larger than the
4926 size of a pointer then a truncation is done. If <tt>value</tt> is smaller
4927 than the size of a pointer then a zero extension is done. If they are the
4928 same size, nothing is done (<i>no-op cast</i>).</p>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]4929
4930<h5>Example:</h5>
4931<pre>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]4932 %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]4933 %Y = inttoptr i32 255 to i32* <i>; yields no-op on 32-bit architecture</i>
4934 %Z = inttoptr i64 0 to i32* <i>; yields truncation on 32-bit architecture</i>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]4935</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4936
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]4937</div>
4938
4939<!-- _______________________________________________________________________ -->
4940<div class="doc_subsubsection">
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]4941 <a name="i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4942</div>
4943<div class="doc_text">
4944
4945<h5>Syntax:</h5>
4946<pre>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]4947 &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]4948</pre>
4949
4950<h5>Overview:</h5>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]4951<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4952 <tt>ty2</tt> without changing any bits.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4953
4954<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4955<p>The '<tt>bitcast</tt>' instruction takes a value to cast, which must be a
4956 non-aggregate first class value, and a type to cast it to, which must also be
4957 a non-aggregate <a href="#t_firstclass">first class</a> type. The bit sizes
4958 of <tt>value</tt> and the destination type, <tt>ty2</tt>, must be
4959 identical. If the source type is a pointer, the destination type must also be
4960 a pointer. This instruction supports bitwise conversion of vectors to
4961 integers and to vectors of other types (as long as they have the same
4962 size).</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4963
4964<h5>Semantics:</h5>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]4965<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4966 <tt>ty2</tt>. It is always a <i>no-op cast</i> because no bits change with
4967 this conversion. The conversion is done as if the <tt>value</tt> had been
4968 stored to memory and read back as type <tt>ty2</tt>. Pointer types may only
4969 be converted to other pointer types with this instruction. To convert
4970 pointers to other types, use the <a href="#i_inttoptr">inttoptr</a> or
4971 <a href="#i_ptrtoint">ptrtoint</a> instructions first.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4972
4973<h5>Example:</h5>
4974<pre>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]4975 %X = bitcast i8 255 to i8 <i>; yields i8 :-1</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4976 %Y = bitcast i32* %x to sint* <i>; yields sint*:%x</i>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4977 %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]4978</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4979
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4980</div>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]4981
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]4982<!-- ======================================================================= -->
4983<div class="doc_subsection"> <a name="otherops">Other Operations</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4984
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]4985<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4986
4987<p>The instructions in this category are the "miscellaneous" instructions, which
4988 defy better classification.</p>
4989
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]4990</div>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4991
4992<!-- _______________________________________________________________________ -->
4993<div class="doc_subsubsection"><a name="i_icmp">'<tt>icmp</tt>' Instruction</a>
4994</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4995
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4996<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4997
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4998<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4999<pre>
5000 &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]5001</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5002
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5003<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5004<p>The '<tt>icmp</tt>' instruction returns a boolean value or a vector of
5005 boolean values based on comparison of its two integer, integer vector, or
5006 pointer operands.</p>
5007
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5008<h5>Arguments:</h5>
5009<p>The '<tt>icmp</tt>' instruction takes three operands. The first operand is
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5010 the condition code indicating the kind of comparison to perform. It is not a
5011 value, just a keyword. The possible condition code are:</p>
5012
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5013<ol>
5014 <li><tt>eq</tt>: equal</li>
5015 <li><tt>ne</tt>: not equal </li>
5016 <li><tt>ugt</tt>: unsigned greater than</li>
5017 <li><tt>uge</tt>: unsigned greater or equal</li>
5018 <li><tt>ult</tt>: unsigned less than</li>
5019 <li><tt>ule</tt>: unsigned less or equal</li>
5020 <li><tt>sgt</tt>: signed greater than</li>
5021 <li><tt>sge</tt>: signed greater or equal</li>
5022 <li><tt>slt</tt>: signed less than</li>
5023 <li><tt>sle</tt>: signed less or equal</li>
5024</ol>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5025
Chris Lattnerc0f423a2007-01-15 01:54:13 +0000[diff] [blame]5026<p>The remaining two arguments must be <a href="#t_integer">integer</a> or
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5027 <a href="#t_pointer">pointer</a> or integer <a href="#t_vector">vector</a>
5028 typed. They must also be identical types.</p>
5029
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5030<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5031<p>The '<tt>icmp</tt>' compares <tt>op1</tt> and <tt>op2</tt> according to the
5032 condition code given as <tt>cond</tt>. The comparison performed always yields
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]5033 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]5034 result, as follows:</p>
5035
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5036<ol>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5037 <li><tt>eq</tt>: yields <tt>true</tt> if the operands are equal,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5038 <tt>false</tt> otherwise. No sign interpretation is necessary or
5039 performed.</li>
5040
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5041 <li><tt>ne</tt>: yields <tt>true</tt> if the operands are unequal,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5042 <tt>false</tt> otherwise. No sign interpretation is necessary or
5043 performed.</li>
5044
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5045 <li><tt>ugt</tt>: interprets the operands as unsigned values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5046 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
5047
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5048 <li><tt>uge</tt>: interprets the operands as unsigned values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5049 <tt>true</tt> if <tt>op1</tt> is greater than or equal
5050 to <tt>op2</tt>.</li>
5051
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5052 <li><tt>ult</tt>: interprets the operands as unsigned values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5053 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
5054
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5055 <li><tt>ule</tt>: interprets the operands as unsigned values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5056 <tt>true</tt> if <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
5057
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5058 <li><tt>sgt</tt>: interprets the operands as signed values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5059 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
5060
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5061 <li><tt>sge</tt>: interprets the operands as signed values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5062 <tt>true</tt> if <tt>op1</tt> is greater than or equal
5063 to <tt>op2</tt>.</li>
5064
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5065 <li><tt>slt</tt>: interprets the operands as signed values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5066 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
5067
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5068 <li><tt>sle</tt>: interprets the operands as signed values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5069 <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]5070</ol>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5071
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5072<p>If the operands are <a href="#t_pointer">pointer</a> typed, the pointer
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5073 values are compared as if they were integers.</p>
5074
5075<p>If the operands are integer vectors, then they are compared element by
5076 element. The result is an <tt>i1</tt> vector with the same number of elements
5077 as the values being compared. Otherwise, the result is an <tt>i1</tt>.</p>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5078
5079<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5080<pre>
5081 &lt;result&gt; = icmp eq i32 4, 5 <i>; yields: result=false</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]5082 &lt;result&gt; = icmp ne float* %X, %X <i>; yields: result=false</i>
5083 &lt;result&gt; = icmp ult i16 4, 5 <i>; yields: result=true</i>
5084 &lt;result&gt; = icmp sgt i16 4, 5 <i>; yields: result=false</i>
5085 &lt;result&gt; = icmp ule i16 -4, 5 <i>; yields: result=false</i>
5086 &lt;result&gt; = icmp sge i16 4, 5 <i>; yields: result=false</i>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5087</pre>
Dan Gohmana5127ab2009-01-22 01:39:38 +0000[diff] [blame]5088
5089<p>Note that the code generator does not yet support vector types with
5090 the <tt>icmp</tt> instruction.</p>
5091
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5092</div>
5093
5094<!-- _______________________________________________________________________ -->
5095<div class="doc_subsubsection"><a name="i_fcmp">'<tt>fcmp</tt>' Instruction</a>
5096</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5097
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5098<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5099
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5100<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5101<pre>
5102 &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]5103</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5104
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5105<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5106<p>The '<tt>fcmp</tt>' instruction returns a boolean value or vector of boolean
5107 values based on comparison of its operands.</p>
5108
5109<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]5110(<a href="#t_integer"><tt>i1</tt></a>).</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5111
5112<p>If the operands are floating point vectors, then the result type is a vector
5113 of boolean with the same number of elements as the operands being
5114 compared.</p>
5115
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5116<h5>Arguments:</h5>
5117<p>The '<tt>fcmp</tt>' instruction takes three operands. The first operand is
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5118 the condition code indicating the kind of comparison to perform. It is not a
5119 value, just a keyword. The possible condition code are:</p>
5120
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5121<ol>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]5122 <li><tt>false</tt>: no comparison, always returns false</li>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5123 <li><tt>oeq</tt>: ordered and equal</li>
5124 <li><tt>ogt</tt>: ordered and greater than </li>
5125 <li><tt>oge</tt>: ordered and greater than or equal</li>
5126 <li><tt>olt</tt>: ordered and less than </li>
5127 <li><tt>ole</tt>: ordered and less than or equal</li>
5128 <li><tt>one</tt>: ordered and not equal</li>
5129 <li><tt>ord</tt>: ordered (no nans)</li>
5130 <li><tt>ueq</tt>: unordered or equal</li>
5131 <li><tt>ugt</tt>: unordered or greater than </li>
5132 <li><tt>uge</tt>: unordered or greater than or equal</li>
5133 <li><tt>ult</tt>: unordered or less than </li>
5134 <li><tt>ule</tt>: unordered or less than or equal</li>
5135 <li><tt>une</tt>: unordered or not equal</li>
5136 <li><tt>uno</tt>: unordered (either nans)</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]5137 <li><tt>true</tt>: no comparison, always returns true</li>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5138</ol>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5139
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5140<p><i>Ordered</i> means that neither operand is a QNAN while
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5141 <i>unordered</i> means that either operand may be a QNAN.</p>
5142
5143<p>Each of <tt>val1</tt> and <tt>val2</tt> arguments must be either
5144 a <a href="#t_floating">floating point</a> type or
5145 a <a href="#t_vector">vector</a> of floating point type. They must have
5146 identical types.</p>
5147
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5148<h5>Semantics:</h5>
Gabor Greif0f75ad02008-08-07 21:46:00 +0000[diff] [blame]5149<p>The '<tt>fcmp</tt>' instruction compares <tt>op1</tt> and <tt>op2</tt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5150 according to the condition code given as <tt>cond</tt>. If the operands are
5151 vectors, then the vectors are compared element by element. Each comparison
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]5152 performed always yields an <a href="#t_integer">i1</a> result, as
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5153 follows:</p>
5154
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5155<ol>
5156 <li><tt>false</tt>: always yields <tt>false</tt>, regardless of operands.</li>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5157
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5158 <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]5159 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
5160
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]5161 <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]5162 <tt>op1</tt> is greater than <tt>op2</tt>.</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>oge</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 greater than or equal to <tt>op2</tt>.</li>
5166
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5167 <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]5168 <tt>op1</tt> is less than <tt>op2</tt>.</li>
5169
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5170 <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]5171 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
5172
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5173 <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]5174 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
5175
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]5176 <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]5177
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5178 <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]5179 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
5180
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5181 <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]5182 <tt>op1</tt> is greater than <tt>op2</tt>.</li>
5183
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5184 <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]5185 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
5186
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5187 <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]5188 <tt>op1</tt> is less than <tt>op2</tt>.</li>
5189
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5190 <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]5191 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
5192
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5193 <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]5194 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
5195
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]5196 <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]5197
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5198 <li><tt>true</tt>: always yields <tt>true</tt>, regardless of operands.</li>
5199</ol>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5200
5201<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5202<pre>
5203 &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]5204 &lt;result&gt; = fcmp one float 4.0, 5.0 <i>; yields: result=true</i>
5205 &lt;result&gt; = fcmp olt float 4.0, 5.0 <i>; yields: result=true</i>
5206 &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]5207</pre>
Dan Gohmana5127ab2009-01-22 01:39:38 +0000[diff] [blame]5208
5209<p>Note that the code generator does not yet support vector types with
5210 the <tt>fcmp</tt> instruction.</p>
5211
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5212</div>
5213
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5214<!-- _______________________________________________________________________ -->
Nate Begemand2195702008-05-12 19:01:56 +0000[diff] [blame]5215<div class="doc_subsubsection">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]5216 <a name="i_phi">'<tt>phi</tt>' Instruction</a>
5217</div>
5218
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5219<div class="doc_text">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]5220
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5221<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5222<pre>
5223 &lt;result&gt; = phi &lt;ty&gt; [ &lt;val0&gt;, &lt;label0&gt;], ...
5224</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]5225
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5226<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5227<p>The '<tt>phi</tt>' instruction is used to implement the &#966; node in the
5228 SSA graph representing the function.</p>
5229
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5230<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5231<p>The type of the incoming values is specified with the first type field. After
5232 this, the '<tt>phi</tt>' instruction takes a list of pairs as arguments, with
5233 one pair for each predecessor basic block of the current block. Only values
5234 of <a href="#t_firstclass">first class</a> type may be used as the value
5235 arguments to the PHI node. Only labels may be used as the label
5236 arguments.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]5237
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5238<p>There must be no non-phi instructions between the start of a basic block and
5239 the PHI instructions: i.e. PHI instructions must be first in a basic
5240 block.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]5241
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5242<p>For the purposes of the SSA form, the use of each incoming value is deemed to
5243 occur on the edge from the corresponding predecessor block to the current
5244 block (but after any definition of an '<tt>invoke</tt>' instruction's return
5245 value on the same edge).</p>
Jay Foad1a4eea52009-06-03 10:20:10 +0000[diff] [blame]5246
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5247<h5>Semantics:</h5>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5248<p>At runtime, the '<tt>phi</tt>' instruction logically takes on the value
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5249 specified by the pair corresponding to the predecessor basic block that
5250 executed just prior to the current block.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]5251
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5252<h5>Example:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]5253<pre>
5254Loop: ; Infinite loop that counts from 0 on up...
5255 %indvar = phi i32 [ 0, %LoopHeader ], [ %nextindvar, %Loop ]
5256 %nextindvar = add i32 %indvar, 1
5257 br label %Loop
5258</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5259
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5260</div>
5261
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5262<!-- _______________________________________________________________________ -->
5263<div class="doc_subsubsection">
5264 <a name="i_select">'<tt>select</tt>' Instruction</a>
5265</div>
5266
5267<div class="doc_text">
5268
5269<h5>Syntax:</h5>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5270<pre>
Dan Gohmanc579d972008-09-09 01:02:47 +0000[diff] [blame]5271 &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>
5272
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]5273 <i>selty</i> is either i1 or {&lt;N x i1&gt;}
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5274</pre>
5275
5276<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5277<p>The '<tt>select</tt>' instruction is used to choose one value based on a
5278 condition, without branching.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5279
5280
5281<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5282<p>The '<tt>select</tt>' instruction requires an 'i1' value or a vector of 'i1'
5283 values indicating the condition, and two values of the
5284 same <a href="#t_firstclass">first class</a> type. If the val1/val2 are
5285 vectors and the condition is a scalar, then entire vectors are selected, not
5286 individual elements.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5287
5288<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5289<p>If the condition is an i1 and it evaluates to 1, the instruction returns the
5290 first value argument; otherwise, it returns the second value argument.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5291
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5292<p>If the condition is a vector of i1, then the value arguments must be vectors
5293 of the same size, and the selection is done element by element.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5294
5295<h5>Example:</h5>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5296<pre>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]5297 %X = select i1 true, i8 17, i8 42 <i>; yields i8:17</i>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5298</pre>
Dan Gohmana5127ab2009-01-22 01:39:38 +0000[diff] [blame]5299
5300<p>Note that the code generator does not yet support conditions
5301 with vector type.</p>
5302
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5303</div>
5304
Robert Bocchinof72fdfe2006-01-15 20:48:27 +0000[diff] [blame]5305<!-- _______________________________________________________________________ -->
5306<div class="doc_subsubsection">
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5307 <a name="i_call">'<tt>call</tt>' Instruction</a>
5308</div>
5309
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5310<div class="doc_text">
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5311
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]5312<h5>Syntax:</h5>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5313<pre>
Devang Patel02256232008-10-07 17:48:33 +0000[diff] [blame]5314 &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]5315</pre>
5316
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]5317<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5318<p>The '<tt>call</tt>' instruction represents a simple function call.</p>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5319
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]5320<h5>Arguments:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5321<p>This instruction requires several arguments:</p>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5322
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]5323<ol>
Jeffrey Yasskinb8677462010-01-09 19:44:16 +0000[diff] [blame]5324 <li>The optional "tail" marker indicates that the callee function does not
5325 access any allocas or varargs in the caller. Note that calls may be
5326 marked "tail" even if they do not occur before
5327 a <a href="#i_ret"><tt>ret</tt></a> instruction. If the "tail" marker is
5328 present, the function call is eligible for tail call optimization,
5329 but <a href="CodeGenerator.html#tailcallopt">might not in fact be
Evan Cheng59676492010-03-08 21:05:02 +0000[diff] [blame]5330 optimized into a jump</a>. The code generator may optimize calls marked
5331 "tail" with either 1) automatic <a href="CodeGenerator.html#sibcallopt">
5332 sibling call optimization</a> when the caller and callee have
5333 matching signatures, or 2) forced tail call optimization when the
5334 following extra requirements are met:
Jeffrey Yasskinb8677462010-01-09 19:44:16 +0000[diff] [blame]5335 <ul>
5336 <li>Caller and callee both have the calling
5337 convention <tt>fastcc</tt>.</li>
5338 <li>The call is in tail position (ret immediately follows call and ret
5339 uses value of call or is void).</li>
5340 <li>Option <tt>-tailcallopt</tt> is enabled,
Dan Gohman6232f732010-03-02 01:08:11 +0000[diff] [blame]5341 or <code>llvm::GuaranteedTailCallOpt</code> is <code>true</code>.</li>
Jeffrey Yasskinb8677462010-01-09 19:44:16 +0000[diff] [blame]5342 <li><a href="CodeGenerator.html#tailcallopt">Platform specific
5343 constraints are met.</a></li>
5344 </ul>
5345 </li>
Devang Patel7e9b05e2008-10-06 18:50:38 +0000[diff] [blame]5346
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5347 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
5348 convention</a> the call should use. If none is specified, the call
Jeffrey Yasskinb8677462010-01-09 19:44:16 +0000[diff] [blame]5349 defaults to using C calling conventions. The calling convention of the
5350 call must match the calling convention of the target function, or else the
5351 behavior is undefined.</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 <a href="#paramattrs">Parameter Attributes</a> list for
5354 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
5355 '<tt>inreg</tt>' attributes are valid here.</li>
5356
5357 <li>'<tt>ty</tt>': the type of the call instruction itself which is also the
5358 type of the return value. Functions that return no value are marked
5359 <tt><a href="#t_void">void</a></tt>.</li>
5360
5361 <li>'<tt>fnty</tt>': shall be the signature of the pointer to function value
5362 being invoked. The argument types must match the types implied by this
5363 signature. This type can be omitted if the function is not varargs and if
5364 the function type does not return a pointer to a function.</li>
5365
5366 <li>'<tt>fnptrval</tt>': An LLVM value containing a pointer to a function to
5367 be invoked. In most cases, this is a direct function invocation, but
5368 indirect <tt>call</tt>s are just as possible, calling an arbitrary pointer
5369 to function value.</li>
5370
5371 <li>'<tt>function args</tt>': argument list whose types match the function
Chris Lattner47f2a832010-03-02 06:36:51 +0000[diff] [blame]5372 signature argument types and parameter attributes. All arguments must be
5373 of <a href="#t_firstclass">first class</a> type. If the function
5374 signature indicates the function accepts a variable number of arguments,
5375 the extra arguments can be specified.</li>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5376
5377 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
5378 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
5379 '<tt>readnone</tt>' attributes are valid here.</li>
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]5380</ol>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5381
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]5382<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5383<p>The '<tt>call</tt>' instruction is used to cause control flow to transfer to
5384 a specified function, with its incoming arguments bound to the specified
5385 values. Upon a '<tt><a href="#i_ret">ret</a></tt>' instruction in the called
5386 function, control flow continues with the instruction after the function
5387 call, and the return value of the function is bound to the result
5388 argument.</p>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5389
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]5390<h5>Example:</h5>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5391<pre>
Nick Lewyckya9b13d52007-09-08 13:57:50 +0000[diff] [blame]5392 %retval = call i32 @test(i32 %argc)
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]5393 call i32 (i8*, ...)* @printf(i8* %msg, i32 12, i8 42) <i>; yields i32</i>
Chris Lattnerfb7c88d2008-03-21 17:24:17 +0000[diff] [blame]5394 %X = tail call i32 @foo() <i>; yields i32</i>
5395 %Y = tail call <a href="#callingconv">fastcc</a> i32 @foo() <i>; yields i32</i>
5396 call void %foo(i8 97 signext)
Devang Pateld6cff512008-03-10 20:49:15 +0000[diff] [blame]5397
5398 %struct.A = type { i32, i8 }
Devang Patel7e9b05e2008-10-06 18:50:38 +0000[diff] [blame]5399 %r = call %struct.A @foo() <i>; yields { 32, i8 }</i>
Dan Gohmancc3132e2008-10-04 19:00:07 +0000[diff] [blame]5400 %gr = extractvalue %struct.A %r, 0 <i>; yields i32</i>
5401 %gr1 = extractvalue %struct.A %r, 1 <i>; yields i8</i>
Chris Lattner6cbe8e92008-10-08 06:26:11 +0000[diff] [blame]5402 %Z = call void @foo() noreturn <i>; indicates that %foo never returns normally</i>
Matthijs Kooijmaneefa7df2008-10-07 10:03:45 +0000[diff] [blame]5403 %ZZ = call zeroext i32 @bar() <i>; Return value is %zero extended</i>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5404</pre>
5405
Dale Johannesen68f971b2009-09-24 18:38:21 +0000[diff] [blame]5406<p>llvm treats calls to some functions with names and arguments that match the
Dale Johannesen722212d2009-09-25 17:04:42 +0000[diff] [blame]5407standard C99 library as being the C99 library functions, and may perform
5408optimizations or generate code for them under that assumption. This is
5409something we'd like to change in the future to provide better support for
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]5410freestanding environments and non-C-based languages.</p>
Dale Johannesen68f971b2009-09-24 18:38:21 +0000[diff] [blame]5411
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5412</div>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5413
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5414<!-- _______________________________________________________________________ -->
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5415<div class="doc_subsubsection">
Chris Lattner33337472006-01-13 23:26:01 +0000[diff] [blame]5416 <a name="i_va_arg">'<tt>va_arg</tt>' Instruction</a>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5417</div>
5418
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5419<div class="doc_text">
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5420
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]5421<h5>Syntax:</h5>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5422<pre>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]5423 &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]5424</pre>
5425
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]5426<h5>Overview:</h5>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]5427<p>The '<tt>va_arg</tt>' instruction is used to access arguments passed through
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5428 the "variable argument" area of a function call. It is used to implement the
5429 <tt>va_arg</tt> macro in C.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5430
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]5431<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5432<p>This instruction takes a <tt>va_list*</tt> value and the type of the
5433 argument. It returns a value of the specified argument type and increments
5434 the <tt>va_list</tt> to point to the next argument. The actual type
5435 of <tt>va_list</tt> is target specific.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5436
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]5437<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5438<p>The '<tt>va_arg</tt>' instruction loads an argument of the specified type
5439 from the specified <tt>va_list</tt> and causes the <tt>va_list</tt> to point
5440 to the next argument. For more information, see the variable argument
5441 handling <a href="#int_varargs">Intrinsic Functions</a>.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5442
5443<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]5444 take a variable number of arguments, for example, the <tt>vfprintf</tt>
5445 function.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5446
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5447<p><tt>va_arg</tt> is an LLVM instruction instead of
5448 an <a href="#intrinsics">intrinsic function</a> because it takes a type as an
5449 argument.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5450
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]5451<h5>Example:</h5>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5452<p>See the <a href="#int_varargs">variable argument processing</a> section.</p>
5453
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5454<p>Note that the code generator does not yet fully support va_arg on many
5455 targets. Also, it does not currently support va_arg with aggregate types on
5456 any target.</p>
Dan Gohman3065b612009-01-12 23:12:39 +0000[diff] [blame]5457
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5458</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5459
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5460<!-- *********************************************************************** -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]5461<div class="doc_section"> <a name="intrinsics">Intrinsic Functions</a> </div>
5462<!-- *********************************************************************** -->
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5463
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5464<div class="doc_text">
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5465
5466<p>LLVM supports the notion of an "intrinsic function". These functions have
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5467 well known names and semantics and are required to follow certain
5468 restrictions. Overall, these intrinsics represent an extension mechanism for
5469 the LLVM language that does not require changing all of the transformations
5470 in LLVM when adding to the language (or the bitcode reader/writer, the
5471 parser, etc...).</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5472
John Criswell88190562005-05-16 16:17:45 +0000[diff] [blame]5473<p>Intrinsic function names must all start with an "<tt>llvm.</tt>" prefix. This
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5474 prefix is reserved in LLVM for intrinsic names; thus, function names may not
5475 begin with this prefix. Intrinsic functions must always be external
5476 functions: you cannot define the body of intrinsic functions. Intrinsic
5477 functions may only be used in call or invoke instructions: it is illegal to
5478 take the address of an intrinsic function. Additionally, because intrinsic
5479 functions are part of the LLVM language, it is required if any are added that
5480 they be documented here.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5481
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5482<p>Some intrinsic functions can be overloaded, i.e., the intrinsic represents a
5483 family of functions that perform the same operation but on different data
5484 types. Because LLVM can represent over 8 million different integer types,
5485 overloading is used commonly to allow an intrinsic function to operate on any
5486 integer type. One or more of the argument types or the result type can be
5487 overloaded to accept any integer type. Argument types may also be defined as
5488 exactly matching a previous argument's type or the result type. This allows
5489 an intrinsic function which accepts multiple arguments, but needs all of them
5490 to be of the same type, to only be overloaded with respect to a single
5491 argument or the result.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5492
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5493<p>Overloaded intrinsics will have the names of its overloaded argument types
5494 encoded into its function name, each preceded by a period. Only those types
5495 which are overloaded result in a name suffix. Arguments whose type is matched
5496 against another type do not. For example, the <tt>llvm.ctpop</tt> function
5497 can take an integer of any width and returns an integer of exactly the same
5498 integer width. This leads to a family of functions such as
5499 <tt>i8 @llvm.ctpop.i8(i8 %val)</tt> and <tt>i29 @llvm.ctpop.i29(i29
5500 %val)</tt>. Only one type, the return type, is overloaded, and only one type
5501 suffix is required. Because the argument's type is matched against the return
5502 type, it does not require its own name suffix.</p>
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]5503
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5504<p>To learn how to add an intrinsic function, please see the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5505 <a href="ExtendingLLVM.html">Extending LLVM Guide</a>.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5506
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5507</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5508
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5509<!-- ======================================================================= -->
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5510<div class="doc_subsection">
5511 <a name="int_varargs">Variable Argument Handling Intrinsics</a>
5512</div>
5513
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5514<div class="doc_text">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5515
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5516<p>Variable argument support is defined in LLVM with
5517 the <a href="#i_va_arg"><tt>va_arg</tt></a> instruction and these three
5518 intrinsic functions. These functions are related to the similarly named
5519 macros defined in the <tt>&lt;stdarg.h&gt;</tt> header file.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5520
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5521<p>All of these functions operate on arguments that use a target-specific value
5522 type "<tt>va_list</tt>". The LLVM assembly language reference manual does
5523 not define what this type is, so all transformations should be prepared to
5524 handle these functions regardless of the type used.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5525
Chris Lattner30b868d2006-05-15 17:26:46 +0000[diff] [blame]5526<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]5527 instruction and the variable argument handling intrinsic functions are
5528 used.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5529
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]5530<pre class="doc_code">
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]5531define i32 @test(i32 %X, ...) {
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5532 ; Initialize variable argument processing
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5533 %ap = alloca i8*
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]5534 %ap2 = bitcast i8** %ap to i8*
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]5535 call void @llvm.va_start(i8* %ap2)
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5536
5537 ; Read a single integer argument
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5538 %tmp = va_arg i8** %ap, i32
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5539
5540 ; Demonstrate usage of llvm.va_copy and llvm.va_end
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5541 %aq = alloca i8*
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]5542 %aq2 = bitcast i8** %aq to i8*
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5543 call void @llvm.va_copy(i8* %aq2, i8* %ap2)
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]5544 call void @llvm.va_end(i8* %aq2)
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5545
5546 ; Stop processing of arguments.
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]5547 call void @llvm.va_end(i8* %ap2)
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]5548 ret i32 %tmp
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5549}
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]5550
5551declare void @llvm.va_start(i8*)
5552declare void @llvm.va_copy(i8*, i8*)
5553declare void @llvm.va_end(i8*)
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5554</pre>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5555
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]5556</div>
5557
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5558<!-- _______________________________________________________________________ -->
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5559<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5560 <a name="int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5561</div>
5562
5563
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5564<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5565
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5566<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5567<pre>
5568 declare void %llvm.va_start(i8* &lt;arglist&gt;)
5569</pre>
5570
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5571<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5572<p>The '<tt>llvm.va_start</tt>' intrinsic initializes <tt>*&lt;arglist&gt;</tt>
5573 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]5574
5575<h5>Arguments:</h5>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]5576<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]5577
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5578<h5>Semantics:</h5>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]5579<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]5580 macro available in C. In a target-dependent way, it initializes
5581 the <tt>va_list</tt> element to which the argument points, so that the next
5582 call to <tt>va_arg</tt> will produce the first variable argument passed to
5583 the function. Unlike the C <tt>va_start</tt> macro, this intrinsic does not
5584 need to know the last argument of the function as the compiler can figure
5585 that out.</p>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]5586
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5587</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5588
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5589<!-- _______________________________________________________________________ -->
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5590<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5591 <a name="int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5592</div>
5593
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5594<div class="doc_text">
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]5595
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5596<h5>Syntax:</h5>
5597<pre>
5598 declare void @llvm.va_end(i8* &lt;arglist&gt;)
5599</pre>
5600
5601<h5>Overview:</h5>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5602<p>The '<tt>llvm.va_end</tt>' intrinsic destroys <tt>*&lt;arglist&gt;</tt>,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5603 which has been initialized previously
5604 with <tt><a href="#int_va_start">llvm.va_start</a></tt>
5605 or <tt><a href="#i_va_copy">llvm.va_copy</a></tt>.</p>
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]5606
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5607<h5>Arguments:</h5>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5608<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]5609
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5610<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5611<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]5612 macro available in C. In a target-dependent way, it destroys
5613 the <tt>va_list</tt> element to which the argument points. Calls
5614 to <a href="#int_va_start"><tt>llvm.va_start</tt></a>
5615 and <a href="#int_va_copy"> <tt>llvm.va_copy</tt></a> must be matched exactly
5616 with calls to <tt>llvm.va_end</tt>.</p>
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]5617
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5618</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5619
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5620<!-- _______________________________________________________________________ -->
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5621<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5622 <a name="int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5623</div>
5624
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5625<div class="doc_text">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5626
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5627<h5>Syntax:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5628<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]5629 declare void @llvm.va_copy(i8* &lt;destarglist&gt;, i8* &lt;srcarglist&gt;)
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5630</pre>
5631
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5632<h5>Overview:</h5>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5633<p>The '<tt>llvm.va_copy</tt>' intrinsic copies the current argument position
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5634 from the source argument list to the destination argument list.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5635
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5636<h5>Arguments:</h5>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]5637<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]5638 The second argument is a pointer to a <tt>va_list</tt> element to copy
5639 from.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5640
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5641<h5>Semantics:</h5>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5642<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]5643 macro available in C. In a target-dependent way, it copies the
5644 source <tt>va_list</tt> element into the destination <tt>va_list</tt>
5645 element. This intrinsic is necessary because
5646 the <tt><a href="#int_va_start"> llvm.va_start</a></tt> intrinsic may be
5647 arbitrarily complex and require, for example, memory allocation.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5648
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5649</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5650
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5651<!-- ======================================================================= -->
5652<div class="doc_subsection">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5653 <a name="int_gc">Accurate Garbage Collection Intrinsics</a>
5654</div>
5655
5656<div class="doc_text">
5657
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5658<p>LLVM support for <a href="GarbageCollection.html">Accurate Garbage
Chris Lattner67c37d12008-08-05 18:29:16 +0000[diff] [blame]5659Collection</a> (GC) requires the implementation and generation of these
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5660intrinsics. These intrinsics allow identification of <a href="#int_gcroot">GC
5661roots on the stack</a>, as well as garbage collector implementations that
5662require <a href="#int_gcread">read</a> and <a href="#int_gcwrite">write</a>
5663barriers. Front-ends for type-safe garbage collected languages should generate
5664these intrinsics to make use of the LLVM garbage collectors. For more details,
5665see <a href="GarbageCollection.html">Accurate Garbage Collection with
5666LLVM</a>.</p>
Christopher Lamb55c6d4f2007-12-17 01:00:21 +0000[diff] [blame]5667
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5668<p>The garbage collection intrinsics only operate on objects in the generic
5669 address space (address space zero).</p>
Christopher Lamb55c6d4f2007-12-17 01:00:21 +0000[diff] [blame]5670
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5671</div>
5672
5673<!-- _______________________________________________________________________ -->
5674<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5675 <a name="int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5676</div>
5677
5678<div class="doc_text">
5679
5680<h5>Syntax:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5681<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]5682 declare void @llvm.gcroot(i8** %ptrloc, i8* %metadata)
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5683</pre>
5684
5685<h5>Overview:</h5>
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]5686<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]5687 the code generator, and allows some metadata to be associated with it.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5688
5689<h5>Arguments:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5690<p>The first argument specifies the address of a stack object that contains the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5691 root pointer. The second pointer (which must be either a constant or a
5692 global value address) contains the meta-data to be associated with the
5693 root.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5694
5695<h5>Semantics:</h5>
Chris Lattner851b7712008-04-24 05:59:56 +0000[diff] [blame]5696<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]5697 location. At compile-time, the code generator generates information to allow
5698 the runtime to find the pointer at GC safe points. The '<tt>llvm.gcroot</tt>'
5699 intrinsic may only be used in a function which <a href="#gc">specifies a GC
5700 algorithm</a>.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5701
5702</div>
5703
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5704<!-- _______________________________________________________________________ -->
5705<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5706 <a name="int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5707</div>
5708
5709<div class="doc_text">
5710
5711<h5>Syntax:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5712<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]5713 declare i8* @llvm.gcread(i8* %ObjPtr, i8** %Ptr)
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5714</pre>
5715
5716<h5>Overview:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5717<p>The '<tt>llvm.gcread</tt>' intrinsic identifies reads of references from heap
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5718 locations, allowing garbage collector implementations that require read
5719 barriers.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5720
5721<h5>Arguments:</h5>
Chris Lattnerf9228072006-03-14 20:02:51 +0000[diff] [blame]5722<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]5723 allocated from the garbage collector. The first object is a pointer to the
5724 start of the referenced object, if needed by the language runtime (otherwise
5725 null).</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5726
5727<h5>Semantics:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5728<p>The '<tt>llvm.gcread</tt>' intrinsic has the same semantics as a load
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5729 instruction, but may be replaced with substantially more complex code by the
5730 garbage collector runtime, as needed. The '<tt>llvm.gcread</tt>' intrinsic
5731 may only be used in a function which <a href="#gc">specifies a GC
5732 algorithm</a>.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5733
5734</div>
5735
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5736<!-- _______________________________________________________________________ -->
5737<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5738 <a name="int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5739</div>
5740
5741<div class="doc_text">
5742
5743<h5>Syntax:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5744<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]5745 declare void @llvm.gcwrite(i8* %P1, i8* %Obj, i8** %P2)
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5746</pre>
5747
5748<h5>Overview:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5749<p>The '<tt>llvm.gcwrite</tt>' intrinsic identifies writes of references to heap
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5750 locations, allowing garbage collector implementations that require write
5751 barriers (such as generational or reference counting collectors).</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5752
5753<h5>Arguments:</h5>
Chris Lattnerf9228072006-03-14 20:02:51 +0000[diff] [blame]5754<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]5755 object to store it to, and the third is the address of the field of Obj to
5756 store to. If the runtime does not require a pointer to the object, Obj may
5757 be null.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5758
5759<h5>Semantics:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5760<p>The '<tt>llvm.gcwrite</tt>' intrinsic has the same semantics as a store
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5761 instruction, but may be replaced with substantially more complex code by the
5762 garbage collector runtime, as needed. The '<tt>llvm.gcwrite</tt>' intrinsic
5763 may only be used in a function which <a href="#gc">specifies a GC
5764 algorithm</a>.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5765
5766</div>
5767
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5768<!-- ======================================================================= -->
5769<div class="doc_subsection">
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5770 <a name="int_codegen">Code Generator Intrinsics</a>
5771</div>
5772
5773<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5774
5775<p>These intrinsics are provided by LLVM to expose special features that may
5776 only be implemented with code generator support.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5777
5778</div>
5779
5780<!-- _______________________________________________________________________ -->
5781<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5782 <a name="int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5783</div>
5784
5785<div class="doc_text">
5786
5787<h5>Syntax:</h5>
5788<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]5789 declare i8 *@llvm.returnaddress(i32 &lt;level&gt;)
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5790</pre>
5791
5792<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5793<p>The '<tt>llvm.returnaddress</tt>' intrinsic attempts to compute a
5794 target-specific value indicating the return address of the current function
5795 or one of its callers.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5796
5797<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5798<p>The argument to this intrinsic indicates which function to return the address
5799 for. Zero indicates the calling function, one indicates its caller, etc.
5800 The argument is <b>required</b> to be a constant integer value.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5801
5802<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5803<p>The '<tt>llvm.returnaddress</tt>' intrinsic either returns a pointer
5804 indicating the return address of the specified call frame, or zero if it
5805 cannot be identified. The value returned by this intrinsic is likely to be
5806 incorrect or 0 for arguments other than zero, so it should only be used for
5807 debugging purposes.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5808
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5809<p>Note that calling this intrinsic does not prevent function inlining or other
5810 aggressive transformations, so the value returned may not be that of the
5811 obvious source-language caller.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5812
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5813</div>
5814
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5815<!-- _______________________________________________________________________ -->
5816<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5817 <a name="int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5818</div>
5819
5820<div class="doc_text">
5821
5822<h5>Syntax:</h5>
5823<pre>
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]5824 declare i8* @llvm.frameaddress(i32 &lt;level&gt;)
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5825</pre>
5826
5827<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5828<p>The '<tt>llvm.frameaddress</tt>' intrinsic attempts to return the
5829 target-specific frame pointer value for the specified stack frame.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5830
5831<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5832<p>The argument to this intrinsic indicates which function to return the frame
5833 pointer for. Zero indicates the calling function, one indicates its caller,
5834 etc. The argument is <b>required</b> to be a constant integer value.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5835
5836<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5837<p>The '<tt>llvm.frameaddress</tt>' intrinsic either returns a pointer
5838 indicating the frame address of the specified call frame, or zero if it
5839 cannot be identified. The value returned by this intrinsic is likely to be
5840 incorrect or 0 for arguments other than zero, so it should only be used for
5841 debugging purposes.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5842
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5843<p>Note that calling this intrinsic does not prevent function inlining or other
5844 aggressive transformations, so the value returned may not be that of the
5845 obvious source-language caller.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5846
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5847</div>
5848
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]5849<!-- _______________________________________________________________________ -->
5850<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5851 <a name="int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]5852</div>
5853
5854<div class="doc_text">
5855
5856<h5>Syntax:</h5>
5857<pre>
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]5858 declare i8* @llvm.stacksave()
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]5859</pre>
5860
5861<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5862<p>The '<tt>llvm.stacksave</tt>' intrinsic is used to remember the current state
5863 of the function stack, for use
5864 with <a href="#int_stackrestore"> <tt>llvm.stackrestore</tt></a>. This is
5865 useful for implementing language features like scoped automatic variable
5866 sized arrays in C99.</p>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]5867
5868<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5869<p>This intrinsic returns a opaque pointer value that can be passed
5870 to <a href="#int_stackrestore"><tt>llvm.stackrestore</tt></a>. When
5871 an <tt>llvm.stackrestore</tt> intrinsic is executed with a value saved
5872 from <tt>llvm.stacksave</tt>, it effectively restores the state of the stack
5873 to the state it was in when the <tt>llvm.stacksave</tt> intrinsic executed.
5874 In practice, this pops any <a href="#i_alloca">alloca</a> blocks from the
5875 stack that were allocated after the <tt>llvm.stacksave</tt> was executed.</p>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]5876
5877</div>
5878
5879<!-- _______________________________________________________________________ -->
5880<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5881 <a name="int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]5882</div>
5883
5884<div class="doc_text">
5885
5886<h5>Syntax:</h5>
5887<pre>
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]5888 declare void @llvm.stackrestore(i8* %ptr)
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]5889</pre>
5890
5891<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5892<p>The '<tt>llvm.stackrestore</tt>' intrinsic is used to restore the state of
5893 the function stack to the state it was in when the
5894 corresponding <a href="#int_stacksave"><tt>llvm.stacksave</tt></a> intrinsic
5895 executed. This is useful for implementing language features like scoped
5896 automatic variable sized arrays in C99.</p>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]5897
5898<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5899<p>See the description
5900 for <a href="#int_stacksave"><tt>llvm.stacksave</tt></a>.</p>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]5901
5902</div>
5903
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]5904<!-- _______________________________________________________________________ -->
5905<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5906 <a name="int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a>
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]5907</div>
5908
5909<div class="doc_text">
5910
5911<h5>Syntax:</h5>
5912<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]5913 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]5914</pre>
5915
5916<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5917<p>The '<tt>llvm.prefetch</tt>' intrinsic is a hint to the code generator to
5918 insert a prefetch instruction if supported; otherwise, it is a noop.
5919 Prefetches have no effect on the behavior of the program but can change its
5920 performance characteristics.</p>
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]5921
5922<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5923<p><tt>address</tt> is the address to be prefetched, <tt>rw</tt> is the
5924 specifier determining if the fetch should be for a read (0) or write (1),
5925 and <tt>locality</tt> is a temporal locality specifier ranging from (0) - no
5926 locality, to (3) - extremely local keep in cache. The <tt>rw</tt>
5927 and <tt>locality</tt> arguments must be constant integers.</p>
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]5928
5929<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5930<p>This intrinsic does not modify the behavior of the program. In particular,
5931 prefetches cannot trap and do not produce a value. On targets that support
5932 this intrinsic, the prefetch can provide hints to the processor cache for
5933 better performance.</p>
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]5934
5935</div>
5936
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]5937<!-- _______________________________________________________________________ -->
5938<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5939 <a name="int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a>
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]5940</div>
5941
5942<div class="doc_text">
5943
5944<h5>Syntax:</h5>
5945<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]5946 declare void @llvm.pcmarker(i32 &lt;id&gt;)
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]5947</pre>
5948
5949<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5950<p>The '<tt>llvm.pcmarker</tt>' intrinsic is a method to export a Program
5951 Counter (PC) in a region of code to simulators and other tools. The method
5952 is target specific, but it is expected that the marker will use exported
5953 symbols to transmit the PC of the marker. The marker makes no guarantees
5954 that it will remain with any specific instruction after optimizations. It is
5955 possible that the presence of a marker will inhibit optimizations. The
5956 intended use is to be inserted after optimizations to allow correlations of
5957 simulation runs.</p>
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]5958
5959<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5960<p><tt>id</tt> is a numerical id identifying the marker.</p>
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]5961
5962<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5963<p>This intrinsic does not modify the behavior of the program. Backends that do
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]5964 not support this intrinsic may ignore it.</p>
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]5965
5966</div>
5967
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]5968<!-- _______________________________________________________________________ -->
5969<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5970 <a name="int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a>
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]5971</div>
5972
5973<div class="doc_text">
5974
5975<h5>Syntax:</h5>
5976<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]5977 declare i64 @llvm.readcyclecounter()
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]5978</pre>
5979
5980<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5981<p>The '<tt>llvm.readcyclecounter</tt>' intrinsic provides access to the cycle
5982 counter register (or similar low latency, high accuracy clocks) on those
5983 targets that support it. On X86, it should map to RDTSC. On Alpha, it
5984 should map to RPCC. As the backing counters overflow quickly (on the order
5985 of 9 seconds on alpha), this should only be used for small timings.</p>
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]5986
5987<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5988<p>When directly supported, reading the cycle counter should not modify any
5989 memory. Implementations are allowed to either return a application specific
5990 value or a system wide value. On backends without support, this is lowered
5991 to a constant 0.</p>
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]5992
5993</div>
5994
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5995<!-- ======================================================================= -->
5996<div class="doc_subsection">
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5997 <a name="int_libc">Standard C Library Intrinsics</a>
5998</div>
5999
6000<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6001
6002<p>LLVM provides intrinsics for a few important standard C library functions.
6003 These intrinsics allow source-language front-ends to pass information about
6004 the alignment of the pointer arguments to the code generator, providing
6005 opportunity for more efficient code generation.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6006
6007</div>
6008
6009<!-- _______________________________________________________________________ -->
6010<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6011 <a name="int_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6012</div>
6013
6014<div class="doc_text">
6015
6016<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6017<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]6018 integer bit width and for different address spaces. Not all targets support
6019 all bit widths however.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6020
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6021<pre>
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]6022 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]6023 i32 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]6024 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]6025 i64 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6026</pre>
6027
6028<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6029<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
6030 source location to the destination location.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6031
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6032<p>Note that, unlike the standard libc function, the <tt>llvm.memcpy.*</tt>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6033 intrinsics do not return a value, takes extra alignment/isvolatile arguments
6034 and the pointers can be in specified address spaces.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6035
6036<h5>Arguments:</h5>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6037
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6038<p>The first argument is a pointer to the destination, the second is a pointer
6039 to the source. The third argument is an integer argument specifying the
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6040 number of bytes to copy, the fourth argument is the alignment of the
6041 source and destination locations, and the fifth is a boolean indicating a
6042 volatile access.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6043
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]6044<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]6045 then the caller guarantees that both the source and destination pointers are
6046 aligned to that boundary.</p>
Chris Lattner4c67c482004-02-12 21:18:15 +0000[diff] [blame]6047
Jeffrey Yasskin5d284ae2010-04-26 21:21:24 +0000[diff] [blame]6048<p>If the <tt>isvolatile</tt> parameter is <tt>true</tt>, the
6049 <tt>llvm.memcpy</tt> call is a <a href="#volatile">volatile operation</a>.
6050 The detailed access behavior is not very cleanly specified and it is unwise
6051 to depend on it.</p>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6052
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6053<h5>Semantics:</h5>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6054
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6055<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
6056 source location to the destination location, which are not allowed to
6057 overlap. It copies "len" bytes of memory over. If the argument is known to
6058 be aligned to some boundary, this can be specified as the fourth argument,
6059 otherwise it should be set to 0 or 1.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6060
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6061</div>
6062
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6063<!-- _______________________________________________________________________ -->
6064<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6065 <a name="int_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a>
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6066</div>
6067
6068<div class="doc_text">
6069
6070<h5>Syntax:</h5>
Chris Lattnerdd708342008-11-21 16:42:48 +0000[diff] [blame]6071<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]6072 width and for different address space. Not all targets support all bit
6073 widths however.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6074
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6075<pre>
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]6076 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]6077 i32 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]6078 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]6079 i64 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6080</pre>
6081
6082<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6083<p>The '<tt>llvm.memmove.*</tt>' intrinsics move a block of memory from the
6084 source location to the destination location. It is similar to the
6085 '<tt>llvm.memcpy</tt>' intrinsic but allows the two memory locations to
6086 overlap.</p>
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6087
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6088<p>Note that, unlike the standard libc function, the <tt>llvm.memmove.*</tt>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6089 intrinsics do not return a value, takes extra alignment/isvolatile arguments
6090 and the pointers can be in specified address spaces.</p>
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6091
6092<h5>Arguments:</h5>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6093
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6094<p>The first argument is a pointer to the destination, the second is a pointer
6095 to the source. The third argument is an integer argument specifying the
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6096 number of bytes to copy, the fourth argument is the alignment of the
6097 source and destination locations, and the fifth is a boolean indicating a
6098 volatile access.</p>
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6099
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]6100<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]6101 then the caller guarantees that the source and destination pointers are
6102 aligned to that boundary.</p>
Chris Lattner4c67c482004-02-12 21:18:15 +0000[diff] [blame]6103
Jeffrey Yasskin5d284ae2010-04-26 21:21:24 +0000[diff] [blame]6104<p>If the <tt>isvolatile</tt> parameter is <tt>true</tt>, the
6105 <tt>llvm.memmove</tt> call is a <a href="#volatile">volatile operation</a>.
6106 The detailed access behavior is not very cleanly specified and it is unwise
6107 to depend on it.</p>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6108
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6109<h5>Semantics:</h5>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6110
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6111<p>The '<tt>llvm.memmove.*</tt>' intrinsics copy a block of memory from the
6112 source location to the destination location, which may overlap. It copies
6113 "len" bytes of memory over. If the argument is known to be aligned to some
6114 boundary, this can be specified as the fourth argument, otherwise it should
6115 be set to 0 or 1.</p>
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6116
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6117</div>
6118
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6119<!-- _______________________________________________________________________ -->
6120<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6121 <a name="int_memset">'<tt>llvm.memset.*</tt>' Intrinsics</a>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6122</div>
6123
6124<div class="doc_text">
6125
6126<h5>Syntax:</h5>
Chris Lattnerdd708342008-11-21 16:42:48 +0000[diff] [blame]6127<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]6128 width and for different address spaces. However, not all targets support all
6129 bit widths.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6130
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6131<pre>
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]6132 declare void @llvm.memset.p0i8.i32(i8* &lt;dest&gt;, i8 &lt;val&gt;,
Chris Lattner685db9d2010-04-08 00:54:34 +0000[diff] [blame]6133 i32 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]6134 declare void @llvm.memset.p0i8.i64(i8* &lt;dest&gt;, i8 &lt;val&gt;,
Chris Lattner685db9d2010-04-08 00:54:34 +0000[diff] [blame]6135 i64 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6136</pre>
6137
6138<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6139<p>The '<tt>llvm.memset.*</tt>' intrinsics fill a block of memory with a
6140 particular byte value.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6141
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6142<p>Note that, unlike the standard libc function, the <tt>llvm.memset</tt>
John Criswellad05ae42010-07-30 16:30:28 +0000[diff] [blame]6143 intrinsic does not return a value and takes extra alignment/volatile
6144 arguments. Also, the destination can be in an arbitrary address space.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6145
6146<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6147<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]6148 byte value with which to fill it, the third argument is an integer argument
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6149 specifying the number of bytes to fill, and the fourth argument is the known
John Criswellad05ae42010-07-30 16:30:28 +0000[diff] [blame]6150 alignment of the destination location.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6151
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]6152<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]6153 then the caller guarantees that the destination pointer is aligned to that
6154 boundary.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6155
Jeffrey Yasskin5d284ae2010-04-26 21:21:24 +0000[diff] [blame]6156<p>If the <tt>isvolatile</tt> parameter is <tt>true</tt>, the
6157 <tt>llvm.memset</tt> call is a <a href="#volatile">volatile operation</a>.
6158 The detailed access behavior is not very cleanly specified and it is unwise
6159 to depend on it.</p>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6160
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6161<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6162<p>The '<tt>llvm.memset.*</tt>' intrinsics fill "len" bytes of memory starting
6163 at the destination location. If the argument is known to be aligned to some
6164 boundary, this can be specified as the fourth argument, otherwise it should
6165 be set to 0 or 1.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6166
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6167</div>
6168
Chris Lattner3b4f4372004-06-11 02:28:03 +0000[diff] [blame]6169<!-- _______________________________________________________________________ -->
6170<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6171 <a name="int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a>
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]6172</div>
6173
6174<div class="doc_text">
6175
6176<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6177<p>This is an overloaded intrinsic. You can use <tt>llvm.sqrt</tt> on any
6178 floating point or vector of floating point type. Not all targets support all
6179 types however.</p>
6180
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]6181<pre>
Dale Johannesendd89d272007-10-02 17:47:38 +0000[diff] [blame]6182 declare float @llvm.sqrt.f32(float %Val)
6183 declare double @llvm.sqrt.f64(double %Val)
6184 declare x86_fp80 @llvm.sqrt.f80(x86_fp80 %Val)
6185 declare fp128 @llvm.sqrt.f128(fp128 %Val)
6186 declare ppc_fp128 @llvm.sqrt.ppcf128(ppc_fp128 %Val)
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]6187</pre>
6188
6189<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6190<p>The '<tt>llvm.sqrt</tt>' intrinsics return the sqrt of the specified operand,
6191 returning the same value as the libm '<tt>sqrt</tt>' functions would.
6192 Unlike <tt>sqrt</tt> in libm, however, <tt>llvm.sqrt</tt> has undefined
6193 behavior for negative numbers other than -0.0 (which allows for better
6194 optimization, because there is no need to worry about errno being
6195 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]6196
6197<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6198<p>The argument and return value are floating point numbers of the same
6199 type.</p>
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]6200
6201<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6202<p>This function returns the sqrt of the specified operand if it is a
6203 nonnegative floating point number.</p>
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]6204
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]6205</div>
6206
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]6207<!-- _______________________________________________________________________ -->
6208<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6209 <a name="int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a>
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]6210</div>
6211
6212<div class="doc_text">
6213
6214<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6215<p>This is an overloaded intrinsic. You can use <tt>llvm.powi</tt> on any
6216 floating point or vector of floating point type. Not all targets support all
6217 types however.</p>
6218
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]6219<pre>
Dale Johannesendd89d272007-10-02 17:47:38 +0000[diff] [blame]6220 declare float @llvm.powi.f32(float %Val, i32 %power)
6221 declare double @llvm.powi.f64(double %Val, i32 %power)
6222 declare x86_fp80 @llvm.powi.f80(x86_fp80 %Val, i32 %power)
6223 declare fp128 @llvm.powi.f128(fp128 %Val, i32 %power)
6224 declare ppc_fp128 @llvm.powi.ppcf128(ppc_fp128 %Val, i32 %power)
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]6225</pre>
6226
6227<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6228<p>The '<tt>llvm.powi.*</tt>' intrinsics return the first operand raised to the
6229 specified (positive or negative) power. The order of evaluation of
6230 multiplications is not defined. When a vector of floating point type is
6231 used, the second argument remains a scalar integer value.</p>
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]6232
6233<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6234<p>The second argument is an integer power, and the first is a value to raise to
6235 that power.</p>
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]6236
6237<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6238<p>This function returns the first value raised to the second power with an
6239 unspecified sequence of rounding operations.</p>
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]6240
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]6241</div>
6242
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6243<!-- _______________________________________________________________________ -->
6244<div class="doc_subsubsection">
6245 <a name="int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a>
6246</div>
6247
6248<div class="doc_text">
6249
6250<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6251<p>This is an overloaded intrinsic. You can use <tt>llvm.sin</tt> on any
6252 floating point or vector of floating point type. Not all targets support all
6253 types however.</p>
6254
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6255<pre>
6256 declare float @llvm.sin.f32(float %Val)
6257 declare double @llvm.sin.f64(double %Val)
6258 declare x86_fp80 @llvm.sin.f80(x86_fp80 %Val)
6259 declare fp128 @llvm.sin.f128(fp128 %Val)
6260 declare ppc_fp128 @llvm.sin.ppcf128(ppc_fp128 %Val)
6261</pre>
6262
6263<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6264<p>The '<tt>llvm.sin.*</tt>' intrinsics return the sine of the operand.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6265
6266<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6267<p>The argument and return value are floating point numbers of the same
6268 type.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6269
6270<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6271<p>This function returns the sine of the specified operand, returning the same
6272 values as the libm <tt>sin</tt> functions would, and handles error conditions
6273 in the same way.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6274
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6275</div>
6276
6277<!-- _______________________________________________________________________ -->
6278<div class="doc_subsubsection">
6279 <a name="int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a>
6280</div>
6281
6282<div class="doc_text">
6283
6284<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6285<p>This is an overloaded intrinsic. You can use <tt>llvm.cos</tt> on any
6286 floating point or vector of floating point type. Not all targets support all
6287 types however.</p>
6288
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6289<pre>
6290 declare float @llvm.cos.f32(float %Val)
6291 declare double @llvm.cos.f64(double %Val)
6292 declare x86_fp80 @llvm.cos.f80(x86_fp80 %Val)
6293 declare fp128 @llvm.cos.f128(fp128 %Val)
6294 declare ppc_fp128 @llvm.cos.ppcf128(ppc_fp128 %Val)
6295</pre>
6296
6297<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6298<p>The '<tt>llvm.cos.*</tt>' intrinsics return the cosine of the operand.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6299
6300<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6301<p>The argument and return value are floating point numbers of the same
6302 type.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6303
6304<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6305<p>This function returns the cosine of the specified operand, returning the same
6306 values as the libm <tt>cos</tt> functions would, and handles error conditions
6307 in the same way.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6308
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6309</div>
6310
6311<!-- _______________________________________________________________________ -->
6312<div class="doc_subsubsection">
6313 <a name="int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a>
6314</div>
6315
6316<div class="doc_text">
6317
6318<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6319<p>This is an overloaded intrinsic. You can use <tt>llvm.pow</tt> on any
6320 floating point or vector of floating point type. Not all targets support all
6321 types however.</p>
6322
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6323<pre>
6324 declare float @llvm.pow.f32(float %Val, float %Power)
6325 declare double @llvm.pow.f64(double %Val, double %Power)
6326 declare x86_fp80 @llvm.pow.f80(x86_fp80 %Val, x86_fp80 %Power)
6327 declare fp128 @llvm.pow.f128(fp128 %Val, fp128 %Power)
6328 declare ppc_fp128 @llvm.pow.ppcf128(ppc_fp128 %Val, ppc_fp128 Power)
6329</pre>
6330
6331<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6332<p>The '<tt>llvm.pow.*</tt>' intrinsics return the first operand raised to the
6333 specified (positive or negative) power.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6334
6335<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6336<p>The second argument is a floating point power, and the first is a value to
6337 raise to that power.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6338
6339<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6340<p>This function returns the first value raised to the second power, returning
6341 the same values as the libm <tt>pow</tt> functions would, and handles error
6342 conditions in the same way.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6343
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6344</div>
6345
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6346<!-- ======================================================================= -->
6347<div class="doc_subsection">
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]6348 <a name="int_manip">Bit Manipulation Intrinsics</a>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6349</div>
6350
6351<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6352
6353<p>LLVM provides intrinsics for a few important bit manipulation operations.
6354 These allow efficient code generation for some algorithms.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6355
6356</div>
6357
6358<!-- _______________________________________________________________________ -->
6359<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6360 <a name="int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a>
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]6361</div>
6362
6363<div class="doc_text">
6364
6365<h5>Syntax:</h5>
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]6366<p>This is an overloaded intrinsic function. You can use bswap on any integer
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6367 type that is an even number of bytes (i.e. BitWidth % 16 == 0).</p>
6368
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]6369<pre>
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]6370 declare i16 @llvm.bswap.i16(i16 &lt;id&gt;)
6371 declare i32 @llvm.bswap.i32(i32 &lt;id&gt;)
6372 declare i64 @llvm.bswap.i64(i64 &lt;id&gt;)
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]6373</pre>
6374
6375<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6376<p>The '<tt>llvm.bswap</tt>' family of intrinsics is used to byte swap integer
6377 values with an even number of bytes (positive multiple of 16 bits). These
6378 are useful for performing operations on data that is not in the target's
6379 native byte order.</p>
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]6380
6381<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6382<p>The <tt>llvm.bswap.i16</tt> intrinsic returns an i16 value that has the high
6383 and low byte of the input i16 swapped. Similarly,
6384 the <tt>llvm.bswap.i32</tt> intrinsic returns an i32 value that has the four
6385 bytes of the input i32 swapped, so that if the input bytes are numbered 0, 1,
6386 2, 3 then the returned i32 will have its bytes in 3, 2, 1, 0 order.
6387 The <tt>llvm.bswap.i48</tt>, <tt>llvm.bswap.i64</tt> and other intrinsics
6388 extend this concept to additional even-byte lengths (6 bytes, 8 bytes and
6389 more, respectively).</p>
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]6390
6391</div>
6392
6393<!-- _______________________________________________________________________ -->
6394<div class="doc_subsubsection">
Reid Spencerb4f9a6f2006-01-16 21:12:35 +0000[diff] [blame]6395 <a name="int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic</a>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6396</div>
6397
6398<div class="doc_text">
6399
6400<h5>Syntax:</h5>
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]6401<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]6402 width. Not all targets support all bit widths however.</p>
6403
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6404<pre>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6405 declare i8 @llvm.ctpop.i8(i8 &lt;src&gt;)
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]6406 declare i16 @llvm.ctpop.i16(i16 &lt;src&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]6407 declare i32 @llvm.ctpop.i32(i32 &lt;src&gt;)
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]6408 declare i64 @llvm.ctpop.i64(i64 &lt;src&gt;)
6409 declare i256 @llvm.ctpop.i256(i256 &lt;src&gt;)
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6410</pre>
6411
6412<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6413<p>The '<tt>llvm.ctpop</tt>' family of intrinsics counts the number of bits set
6414 in a value.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6415
6416<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6417<p>The only argument is the value to be counted. The argument may be of any
6418 integer type. The return type must match the argument type.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6419
6420<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6421<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]6422
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6423</div>
6424
6425<!-- _______________________________________________________________________ -->
6426<div class="doc_subsubsection">
Chris Lattnerb748c672006-01-16 22:34:14 +0000[diff] [blame]6427 <a name="int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic</a>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6428</div>
6429
6430<div class="doc_text">
6431
6432<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6433<p>This is an overloaded intrinsic. You can use <tt>llvm.ctlz</tt> on any
6434 integer bit width. Not all targets support all bit widths however.</p>
6435
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6436<pre>
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]6437 declare i8 @llvm.ctlz.i8 (i8 &lt;src&gt;)
6438 declare i16 @llvm.ctlz.i16(i16 &lt;src&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]6439 declare i32 @llvm.ctlz.i32(i32 &lt;src&gt;)
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]6440 declare i64 @llvm.ctlz.i64(i64 &lt;src&gt;)
6441 declare i256 @llvm.ctlz.i256(i256 &lt;src&gt;)
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6442</pre>
6443
6444<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6445<p>The '<tt>llvm.ctlz</tt>' family of intrinsic functions counts the number of
6446 leading zeros in a variable.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6447
6448<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6449<p>The only argument is the value to be counted. The argument may be of any
6450 integer type. The return type must match the argument type.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6451
6452<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6453<p>The '<tt>llvm.ctlz</tt>' intrinsic counts the leading (most significant)
6454 zeros in a variable. If the src == 0 then the result is the size in bits of
6455 the type of src. For example, <tt>llvm.ctlz(i32 2) = 30</tt>.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6456
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6457</div>
Chris Lattner3b4f4372004-06-11 02:28:03 +0000[diff] [blame]6458
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]6459<!-- _______________________________________________________________________ -->
6460<div class="doc_subsubsection">
Chris Lattnerb748c672006-01-16 22:34:14 +0000[diff] [blame]6461 <a name="int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic</a>
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]6462</div>
6463
6464<div class="doc_text">
6465
6466<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6467<p>This is an overloaded intrinsic. You can use <tt>llvm.cttz</tt> on any
6468 integer bit width. Not all targets support all bit widths however.</p>
6469
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]6470<pre>
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]6471 declare i8 @llvm.cttz.i8 (i8 &lt;src&gt;)
6472 declare i16 @llvm.cttz.i16(i16 &lt;src&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]6473 declare i32 @llvm.cttz.i32(i32 &lt;src&gt;)
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]6474 declare i64 @llvm.cttz.i64(i64 &lt;src&gt;)
6475 declare i256 @llvm.cttz.i256(i256 &lt;src&gt;)
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]6476</pre>
6477
6478<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6479<p>The '<tt>llvm.cttz</tt>' family of intrinsic functions counts the number of
6480 trailing zeros.</p>
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]6481
6482<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6483<p>The only argument is the value to be counted. The argument may be of any
6484 integer type. The return type must match the argument type.</p>
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]6485
6486<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6487<p>The '<tt>llvm.cttz</tt>' intrinsic counts the trailing (least significant)
6488 zeros in a variable. If the src == 0 then the result is the size in bits of
6489 the type of src. For example, <tt>llvm.cttz(2) = 1</tt>.</p>
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]6490
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]6491</div>
6492
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]6493<!-- ======================================================================= -->
6494<div class="doc_subsection">
6495 <a name="int_overflow">Arithmetic with Overflow Intrinsics</a>
6496</div>
6497
6498<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6499
6500<p>LLVM provides intrinsics for some arithmetic with overflow operations.</p>
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]6501
6502</div>
6503
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6504<!-- _______________________________________________________________________ -->
6505<div class="doc_subsubsection">
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]6506 <a name="int_sadd_overflow">'<tt>llvm.sadd.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6507</div>
6508
6509<div class="doc_text">
6510
6511<h5>Syntax:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6512<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]6513 on any integer bit width.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6514
6515<pre>
6516 declare {i16, i1} @llvm.sadd.with.overflow.i16(i16 %a, i16 %b)
6517 declare {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
6518 declare {i64, i1} @llvm.sadd.with.overflow.i64(i64 %a, i64 %b)
6519</pre>
6520
6521<h5>Overview:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6522<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6523 a signed addition of the two arguments, and indicate whether an overflow
6524 occurred during the signed summation.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6525
6526<h5>Arguments:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6527<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]6528 be of integer types of any bit width, but they must have the same bit
6529 width. The second element of the result structure must be of
6530 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6531 undergo signed addition.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6532
6533<h5>Semantics:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6534<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6535 a signed addition of the two variables. They return a structure &mdash; the
6536 first element of which is the signed summation, and the second element of
6537 which is a bit specifying if the signed summation resulted in an
6538 overflow.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6539
6540<h5>Examples:</h5>
6541<pre>
6542 %res = call {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
6543 %sum = extractvalue {i32, i1} %res, 0
6544 %obit = extractvalue {i32, i1} %res, 1
6545 br i1 %obit, label %overflow, label %normal
6546</pre>
6547
6548</div>
6549
6550<!-- _______________________________________________________________________ -->
6551<div class="doc_subsubsection">
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]6552 <a name="int_uadd_overflow">'<tt>llvm.uadd.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6553</div>
6554
6555<div class="doc_text">
6556
6557<h5>Syntax:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6558<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]6559 on any integer bit width.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6560
6561<pre>
6562 declare {i16, i1} @llvm.uadd.with.overflow.i16(i16 %a, i16 %b)
6563 declare {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
6564 declare {i64, i1} @llvm.uadd.with.overflow.i64(i64 %a, i64 %b)
6565</pre>
6566
6567<h5>Overview:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6568<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6569 an unsigned addition of the two arguments, and indicate whether a carry
6570 occurred during the unsigned summation.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6571
6572<h5>Arguments:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6573<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]6574 be of integer types of any bit width, but they must have the same bit
6575 width. The second element of the result structure must be of
6576 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6577 undergo unsigned addition.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6578
6579<h5>Semantics:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6580<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6581 an unsigned addition of the two arguments. They return a structure &mdash;
6582 the first element of which is the sum, and the second element of which is a
6583 bit specifying if the unsigned summation resulted in a carry.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6584
6585<h5>Examples:</h5>
6586<pre>
6587 %res = call {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
6588 %sum = extractvalue {i32, i1} %res, 0
6589 %obit = extractvalue {i32, i1} %res, 1
6590 br i1 %obit, label %carry, label %normal
6591</pre>
6592
6593</div>
6594
6595<!-- _______________________________________________________________________ -->
6596<div class="doc_subsubsection">
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]6597 <a name="int_ssub_overflow">'<tt>llvm.ssub.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6598</div>
6599
6600<div class="doc_text">
6601
6602<h5>Syntax:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6603<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]6604 on any integer bit width.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6605
6606<pre>
6607 declare {i16, i1} @llvm.ssub.with.overflow.i16(i16 %a, i16 %b)
6608 declare {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
6609 declare {i64, i1} @llvm.ssub.with.overflow.i64(i64 %a, i64 %b)
6610</pre>
6611
6612<h5>Overview:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6613<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6614 a signed subtraction of the two arguments, and indicate whether an overflow
6615 occurred during the signed subtraction.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6616
6617<h5>Arguments:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6618<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]6619 be of integer types of any bit width, but they must have the same bit
6620 width. The second element of the result structure must be of
6621 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6622 undergo signed subtraction.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6623
6624<h5>Semantics:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6625<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6626 a signed subtraction of the two arguments. They return a structure &mdash;
6627 the first element of which is the subtraction, and the second element of
6628 which is a bit specifying if the signed subtraction resulted in an
6629 overflow.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6630
6631<h5>Examples:</h5>
6632<pre>
6633 %res = call {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
6634 %sum = extractvalue {i32, i1} %res, 0
6635 %obit = extractvalue {i32, i1} %res, 1
6636 br i1 %obit, label %overflow, label %normal
6637</pre>
6638
6639</div>
6640
6641<!-- _______________________________________________________________________ -->
6642<div class="doc_subsubsection">
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]6643 <a name="int_usub_overflow">'<tt>llvm.usub.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6644</div>
6645
6646<div class="doc_text">
6647
6648<h5>Syntax:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6649<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]6650 on any integer bit width.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6651
6652<pre>
6653 declare {i16, i1} @llvm.usub.with.overflow.i16(i16 %a, i16 %b)
6654 declare {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
6655 declare {i64, i1} @llvm.usub.with.overflow.i64(i64 %a, i64 %b)
6656</pre>
6657
6658<h5>Overview:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6659<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6660 an unsigned subtraction of the two arguments, and indicate whether an
6661 overflow occurred during the unsigned subtraction.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6662
6663<h5>Arguments:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6664<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]6665 be of integer types of any bit width, but they must have the same bit
6666 width. The second element of the result structure must be of
6667 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6668 undergo unsigned subtraction.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6669
6670<h5>Semantics:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6671<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6672 an unsigned subtraction of the two arguments. They return a structure &mdash;
6673 the first element of which is the subtraction, and the second element of
6674 which is a bit specifying if the unsigned subtraction resulted in an
6675 overflow.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6676
6677<h5>Examples:</h5>
6678<pre>
6679 %res = call {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
6680 %sum = extractvalue {i32, i1} %res, 0
6681 %obit = extractvalue {i32, i1} %res, 1
6682 br i1 %obit, label %overflow, label %normal
6683</pre>
6684
6685</div>
6686
6687<!-- _______________________________________________________________________ -->
6688<div class="doc_subsubsection">
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]6689 <a name="int_smul_overflow">'<tt>llvm.smul.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6690</div>
6691
6692<div class="doc_text">
6693
6694<h5>Syntax:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6695<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]6696 on any integer bit width.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6697
6698<pre>
6699 declare {i16, i1} @llvm.smul.with.overflow.i16(i16 %a, i16 %b)
6700 declare {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
6701 declare {i64, i1} @llvm.smul.with.overflow.i64(i64 %a, i64 %b)
6702</pre>
6703
6704<h5>Overview:</h5>
6705
6706<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6707 a signed multiplication of the two arguments, and indicate whether an
6708 overflow occurred during the signed multiplication.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6709
6710<h5>Arguments:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6711<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]6712 be of integer types of any bit width, but they must have the same bit
6713 width. The second element of the result structure must be of
6714 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6715 undergo signed multiplication.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6716
6717<h5>Semantics:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6718<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6719 a signed multiplication of the two arguments. They return a structure &mdash;
6720 the first element of which is the multiplication, and the second element of
6721 which is a bit specifying if the signed multiplication resulted in an
6722 overflow.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6723
6724<h5>Examples:</h5>
6725<pre>
6726 %res = call {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
6727 %sum = extractvalue {i32, i1} %res, 0
6728 %obit = extractvalue {i32, i1} %res, 1
6729 br i1 %obit, label %overflow, label %normal
6730</pre>
6731
Reid Spencer5bf54c82007-04-11 23:23:49 +0000[diff] [blame]6732</div>
6733
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]6734<!-- _______________________________________________________________________ -->
6735<div class="doc_subsubsection">
6736 <a name="int_umul_overflow">'<tt>llvm.umul.with.overflow.*</tt>' Intrinsics</a>
6737</div>
6738
6739<div class="doc_text">
6740
6741<h5>Syntax:</h5>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]6742<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]6743 on any integer bit width.</p>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]6744
6745<pre>
6746 declare {i16, i1} @llvm.umul.with.overflow.i16(i16 %a, i16 %b)
6747 declare {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
6748 declare {i64, i1} @llvm.umul.with.overflow.i64(i64 %a, i64 %b)
6749</pre>
6750
6751<h5>Overview:</h5>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]6752<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6753 a unsigned multiplication of the two arguments, and indicate whether an
6754 overflow occurred during the unsigned multiplication.</p>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]6755
6756<h5>Arguments:</h5>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]6757<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]6758 be of integer types of any bit width, but they must have the same bit
6759 width. The second element of the result structure must be of
6760 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6761 undergo unsigned multiplication.</p>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]6762
6763<h5>Semantics:</h5>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]6764<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6765 an unsigned multiplication of the two arguments. They return a structure
6766 &mdash; the first element of which is the multiplication, and the second
6767 element of which is a bit specifying if the unsigned multiplication resulted
6768 in an overflow.</p>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]6769
6770<h5>Examples:</h5>
6771<pre>
6772 %res = call {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
6773 %sum = extractvalue {i32, i1} %res, 0
6774 %obit = extractvalue {i32, i1} %res, 1
6775 br i1 %obit, label %overflow, label %normal
6776</pre>
6777
6778</div>
6779
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]6780<!-- ======================================================================= -->
6781<div class="doc_subsection">
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]6782 <a name="int_fp16">Half Precision Floating Point Intrinsics</a>
6783</div>
6784
6785<div class="doc_text">
6786
Chris Lattner022a9fb2010-03-15 04:12:21 +0000[diff] [blame]6787<p>Half precision floating point is a storage-only format. This means that it is
6788 a dense encoding (in memory) but does not support computation in the
6789 format.</p>
Chris Lattnerbbd8bd32010-03-14 23:03:31 +0000[diff] [blame]6790
Chris Lattner022a9fb2010-03-15 04:12:21 +0000[diff] [blame]6791<p>This means that code must first load the half-precision floating point
Chris Lattnerbbd8bd32010-03-14 23:03:31 +0000[diff] [blame]6792 value as an i16, then convert it to float with <a
6793 href="#int_convert_from_fp16"><tt>llvm.convert.from.fp16</tt></a>.
6794 Computation can then be performed on the float value (including extending to
Chris Lattner022a9fb2010-03-15 04:12:21 +0000[diff] [blame]6795 double etc). To store the value back to memory, it is first converted to
6796 float if needed, then converted to i16 with
Chris Lattnerbbd8bd32010-03-14 23:03:31 +0000[diff] [blame]6797 <a href="#int_convert_to_fp16"><tt>llvm.convert.to.fp16</tt></a>, then
6798 storing as an i16 value.</p>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]6799</div>
6800
6801<!-- _______________________________________________________________________ -->
6802<div class="doc_subsubsection">
Chris Lattnerbbd8bd32010-03-14 23:03:31 +0000[diff] [blame]6803 <a name="int_convert_to_fp16">'<tt>llvm.convert.to.fp16</tt>' Intrinsic</a>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]6804</div>
6805
6806<div class="doc_text">
6807
6808<h5>Syntax:</h5>
6809<pre>
6810 declare i16 @llvm.convert.to.fp16(f32 %a)
6811</pre>
6812
6813<h5>Overview:</h5>
6814<p>The '<tt>llvm.convert.to.fp16</tt>' intrinsic function performs
6815 a conversion from single precision floating point format to half precision
6816 floating point format.</p>
6817
6818<h5>Arguments:</h5>
6819<p>The intrinsic function contains single argument - the value to be
6820 converted.</p>
6821
6822<h5>Semantics:</h5>
6823<p>The '<tt>llvm.convert.to.fp16</tt>' intrinsic function performs
6824 a conversion from single precision floating point format to half precision
Chris Lattner022a9fb2010-03-15 04:12:21 +0000[diff] [blame]6825 floating point format. The return value is an <tt>i16</tt> which
Chris Lattnerbbd8bd32010-03-14 23:03:31 +0000[diff] [blame]6826 contains the converted number.</p>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]6827
6828<h5>Examples:</h5>
6829<pre>
6830 %res = call i16 @llvm.convert.to.fp16(f32 %a)
6831 store i16 %res, i16* @x, align 2
6832</pre>
6833
6834</div>
6835
6836<!-- _______________________________________________________________________ -->
6837<div class="doc_subsubsection">
Chris Lattnerbbd8bd32010-03-14 23:03:31 +0000[diff] [blame]6838 <a name="int_convert_from_fp16">'<tt>llvm.convert.from.fp16</tt>' Intrinsic</a>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]6839</div>
6840
6841<div class="doc_text">
6842
6843<h5>Syntax:</h5>
6844<pre>
6845 declare f32 @llvm.convert.from.fp16(i16 %a)
6846</pre>
6847
6848<h5>Overview:</h5>
6849<p>The '<tt>llvm.convert.from.fp16</tt>' intrinsic function performs
6850 a conversion from half precision floating point format to single precision
6851 floating point format.</p>
6852
6853<h5>Arguments:</h5>
6854<p>The intrinsic function contains single argument - the value to be
6855 converted.</p>
6856
6857<h5>Semantics:</h5>
6858<p>The '<tt>llvm.convert.from.fp16</tt>' intrinsic function performs a
Chris Lattner022a9fb2010-03-15 04:12:21 +0000[diff] [blame]6859 conversion from half single precision floating point format to single
Chris Lattnerbbd8bd32010-03-14 23:03:31 +0000[diff] [blame]6860 precision floating point format. The input half-float value is represented by
6861 an <tt>i16</tt> value.</p>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]6862
6863<h5>Examples:</h5>
6864<pre>
6865 %a = load i16* @x, align 2
6866 %res = call f32 @llvm.convert.from.fp16(i16 %a)
6867</pre>
6868
6869</div>
6870
6871<!-- ======================================================================= -->
6872<div class="doc_subsection">
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]6873 <a name="int_debugger">Debugger Intrinsics</a>
6874</div>
6875
6876<div class="doc_text">
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]6877
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6878<p>The LLVM debugger intrinsics (which all start with <tt>llvm.dbg.</tt>
6879 prefix), are described in
6880 the <a href="SourceLevelDebugging.html#format_common_intrinsics">LLVM Source
6881 Level Debugging</a> document.</p>
6882
6883</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]6884
Jim Laskey2211f492007-03-14 19:31:19 +0000[diff] [blame]6885<!-- ======================================================================= -->
6886<div class="doc_subsection">
6887 <a name="int_eh">Exception Handling Intrinsics</a>
6888</div>
6889
6890<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6891
6892<p>The LLVM exception handling intrinsics (which all start with
6893 <tt>llvm.eh.</tt> prefix), are described in
6894 the <a href="ExceptionHandling.html#format_common_intrinsics">LLVM Exception
6895 Handling</a> document.</p>
6896
Jim Laskey2211f492007-03-14 19:31:19 +0000[diff] [blame]6897</div>
6898
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]6899<!-- ======================================================================= -->
6900<div class="doc_subsection">
Duncan Sands86e01192007-09-11 14:10:23 +0000[diff] [blame]6901 <a name="int_trampoline">Trampoline Intrinsic</a>
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]6902</div>
6903
6904<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6905
6906<p>This intrinsic makes it possible to excise one parameter, marked with
Dan Gohman3770af52010-07-02 23:18:08 +0000[diff] [blame]6907 the <a href="#nest"><tt>nest</tt></a> attribute, from a function.
6908 The result is a callable
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6909 function pointer lacking the nest parameter - the caller does not need to
6910 provide a value for it. Instead, the value to use is stored in advance in a
6911 "trampoline", a block of memory usually allocated on the stack, which also
6912 contains code to splice the nest value into the argument list. This is used
6913 to implement the GCC nested function address extension.</p>
6914
6915<p>For example, if the function is
6916 <tt>i32 f(i8* nest %c, i32 %x, i32 %y)</tt> then the resulting function
6917 pointer has signature <tt>i32 (i32, i32)*</tt>. It can be created as
6918 follows:</p>
6919
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]6920<pre class="doc_code">
Duncan Sands86e01192007-09-11 14:10:23 +0000[diff] [blame]6921 %tramp = alloca [10 x i8], align 4 ; size and alignment only correct for X86
6922 %tramp1 = getelementptr [10 x i8]* %tramp, i32 0, i32 0
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]6923 %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]6924 %fp = bitcast i8* %p to i32 (i32, i32)*
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]6925</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6926
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]6927<p>The call <tt>%val = call i32 %fp(i32 %x, i32 %y)</tt> is then equivalent
6928 to <tt>%val = call i32 %f(i8* %nval, i32 %x, i32 %y)</tt>.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6929
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]6930</div>
6931
6932<!-- _______________________________________________________________________ -->
6933<div class="doc_subsubsection">
6934 <a name="int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a>
6935</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6936
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]6937<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6938
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]6939<h5>Syntax:</h5>
6940<pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6941 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]6942</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6943
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]6944<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6945<p>This fills the memory pointed to by <tt>tramp</tt> with code and returns a
6946 function pointer suitable for executing it.</p>
6947
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]6948<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6949<p>The <tt>llvm.init.trampoline</tt> intrinsic takes three arguments, all
6950 pointers. The <tt>tramp</tt> argument must point to a sufficiently large and
6951 sufficiently aligned block of memory; this memory is written to by the
6952 intrinsic. Note that the size and the alignment are target-specific - LLVM
6953 currently provides no portable way of determining them, so a front-end that
6954 generates this intrinsic needs to have some target-specific knowledge.
6955 The <tt>func</tt> argument must hold a function bitcast to
6956 an <tt>i8*</tt>.</p>
6957
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]6958<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6959<p>The block of memory pointed to by <tt>tramp</tt> is filled with target
6960 dependent code, turning it into a function. A pointer to this function is
6961 returned, but needs to be bitcast to an <a href="#int_trampoline">appropriate
6962 function pointer type</a> before being called. The new function's signature
6963 is the same as that of <tt>func</tt> with any arguments marked with
6964 the <tt>nest</tt> attribute removed. At most one such <tt>nest</tt> argument
6965 is allowed, and it must be of pointer type. Calling the new function is
6966 equivalent to calling <tt>func</tt> with the same argument list, but
6967 with <tt>nval</tt> used for the missing <tt>nest</tt> argument. If, after
6968 calling <tt>llvm.init.trampoline</tt>, the memory pointed to
6969 by <tt>tramp</tt> is modified, then the effect of any later call to the
6970 returned function pointer is undefined.</p>
6971
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]6972</div>
6973
6974<!-- ======================================================================= -->
6975<div class="doc_subsection">
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]6976 <a name="int_atomics">Atomic Operations and Synchronization Intrinsics</a>
6977</div>
6978
6979<div class="doc_text">
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]6980
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6981<p>These intrinsic functions expand the "universal IR" of LLVM to represent
6982 hardware constructs for atomic operations and memory synchronization. This
6983 provides an interface to the hardware, not an interface to the programmer. It
6984 is aimed at a low enough level to allow any programming models or APIs
6985 (Application Programming Interfaces) which need atomic behaviors to map
6986 cleanly onto it. It is also modeled primarily on hardware behavior. Just as
6987 hardware provides a "universal IR" for source languages, it also provides a
6988 starting point for developing a "universal" atomic operation and
6989 synchronization IR.</p>
6990
6991<p>These do <em>not</em> form an API such as high-level threading libraries,
6992 software transaction memory systems, atomic primitives, and intrinsic
6993 functions as found in BSD, GNU libc, atomic_ops, APR, and other system and
6994 application libraries. The hardware interface provided by LLVM should allow
6995 a clean implementation of all of these APIs and parallel programming models.
6996 No one model or paradigm should be selected above others unless the hardware
6997 itself ubiquitously does so.</p>
6998
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]6999</div>
7000
7001<!-- _______________________________________________________________________ -->
7002<div class="doc_subsubsection">
7003 <a name="int_memory_barrier">'<tt>llvm.memory.barrier</tt>' Intrinsic</a>
7004</div>
7005<div class="doc_text">
7006<h5>Syntax:</h5>
7007<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7008 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]7009</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7010
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7011<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7012<p>The <tt>llvm.memory.barrier</tt> intrinsic guarantees ordering between
7013 specific pairs of memory access types.</p>
7014
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7015<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7016<p>The <tt>llvm.memory.barrier</tt> intrinsic requires five boolean arguments.
7017 The first four arguments enables a specific barrier as listed below. The
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]7018 fifth argument specifies that the barrier applies to io or device or uncached
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7019 memory.</p>
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7020
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7021<ul>
7022 <li><tt>ll</tt>: load-load barrier</li>
7023 <li><tt>ls</tt>: load-store barrier</li>
7024 <li><tt>sl</tt>: store-load barrier</li>
7025 <li><tt>ss</tt>: store-store barrier</li>
7026 <li><tt>device</tt>: barrier applies to device and uncached memory also.</li>
7027</ul>
7028
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7029<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7030<p>This intrinsic causes the system to enforce some ordering constraints upon
7031 the loads and stores of the program. This barrier does not
7032 indicate <em>when</em> any events will occur, it only enforces
7033 an <em>order</em> in which they occur. For any of the specified pairs of load
7034 and store operations (f.ex. load-load, or store-load), all of the first
7035 operations preceding the barrier will complete before any of the second
7036 operations succeeding the barrier begin. Specifically the semantics for each
7037 pairing is as follows:</p>
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7038
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7039<ul>
7040 <li><tt>ll</tt>: All loads before the barrier must complete before any load
7041 after the barrier begins.</li>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]7042 <li><tt>ls</tt>: All loads before the barrier must complete before any
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7043 store after the barrier begins.</li>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]7044 <li><tt>ss</tt>: All stores before the barrier must complete before any
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7045 store after the barrier begins.</li>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]7046 <li><tt>sl</tt>: All stores before the barrier must complete before any
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7047 load after the barrier begins.</li>
7048</ul>
7049
7050<p>These semantics are applied with a logical "and" behavior when more than one
7051 is enabled in a single memory barrier intrinsic.</p>
7052
7053<p>Backends may implement stronger barriers than those requested when they do
7054 not support as fine grained a barrier as requested. Some architectures do
7055 not need all types of barriers and on such architectures, these become
7056 noops.</p>
7057
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7058<h5>Example:</h5>
7059<pre>
Victor Hernandeza70c6df2009-10-26 23:44:29 +0000[diff] [blame]7060%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7061%ptr = bitcast i8* %mallocP to i32*
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7062 store i32 4, %ptr
7063
7064%result1 = load i32* %ptr <i>; yields {i32}:result1 = 4</i>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7065 call void @llvm.memory.barrier(i1 false, i1 true, i1 false, i1 false)
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7066 <i>; guarantee the above finishes</i>
7067 store i32 8, %ptr <i>; before this begins</i>
7068</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7069
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7070</div>
7071
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7072<!-- _______________________________________________________________________ -->
7073<div class="doc_subsubsection">
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7074 <a name="int_atomic_cmp_swap">'<tt>llvm.atomic.cmp.swap.*</tt>' Intrinsic</a>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7075</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7076
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7077<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7078
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7079<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7080<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.cmp.swap</tt> on
7081 any integer bit width and for different address spaces. Not all targets
7082 support all bit widths however.</p>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7083
7084<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7085 declare i8 @llvm.atomic.cmp.swap.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;cmp&gt;, i8 &lt;val&gt;)
7086 declare i16 @llvm.atomic.cmp.swap.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;cmp&gt;, i16 &lt;val&gt;)
7087 declare i32 @llvm.atomic.cmp.swap.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;cmp&gt;, i32 &lt;val&gt;)
7088 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]7089</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7090
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7091<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7092<p>This loads a value in memory and compares it to a given value. If they are
7093 equal, it stores a new value into the memory.</p>
7094
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7095<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7096<p>The <tt>llvm.atomic.cmp.swap</tt> intrinsic takes three arguments. The result
7097 as well as both <tt>cmp</tt> and <tt>val</tt> must be integer values with the
7098 same bit width. The <tt>ptr</tt> argument must be a pointer to a value of
7099 this integer type. While any bit width integer may be used, targets may only
7100 lower representations they support in hardware.</p>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7101
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7102<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7103<p>This entire intrinsic must be executed atomically. It first loads the value
7104 in memory pointed to by <tt>ptr</tt> and compares it with the
7105 value <tt>cmp</tt>. If they are equal, <tt>val</tt> is stored into the
7106 memory. The loaded value is yielded in all cases. This provides the
7107 equivalent of an atomic compare-and-swap operation within the SSA
7108 framework.</p>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7109
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7110<h5>Examples:</h5>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7111<pre>
Victor Hernandeza70c6df2009-10-26 23:44:29 +0000[diff] [blame]7112%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7113%ptr = bitcast i8* %mallocP to i32*
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7114 store i32 4, %ptr
7115
7116%val1 = add i32 4, 4
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7117%result1 = call i32 @llvm.atomic.cmp.swap.i32.p0i32(i32* %ptr, i32 4, %val1)
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7118 <i>; yields {i32}:result1 = 4</i>
7119%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
7120%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
7121
7122%val2 = add i32 1, 1
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7123%result2 = call i32 @llvm.atomic.cmp.swap.i32.p0i32(i32* %ptr, i32 5, %val2)
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7124 <i>; yields {i32}:result2 = 8</i>
7125%stored2 = icmp eq i32 %result2, 5 <i>; yields {i1}:stored2 = false</i>
7126
7127%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 8</i>
7128</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7129
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7130</div>
7131
7132<!-- _______________________________________________________________________ -->
7133<div class="doc_subsubsection">
7134 <a name="int_atomic_swap">'<tt>llvm.atomic.swap.*</tt>' Intrinsic</a>
7135</div>
7136<div class="doc_text">
7137<h5>Syntax:</h5>
7138
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7139<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.swap</tt> on any
7140 integer bit width. Not all targets support all bit widths however.</p>
7141
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7142<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7143 declare i8 @llvm.atomic.swap.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;val&gt;)
7144 declare i16 @llvm.atomic.swap.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;val&gt;)
7145 declare i32 @llvm.atomic.swap.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;val&gt;)
7146 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]7147</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7148
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7149<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7150<p>This intrinsic loads the value stored in memory at <tt>ptr</tt> and yields
7151 the value from memory. It then stores the value in <tt>val</tt> in the memory
7152 at <tt>ptr</tt>.</p>
7153
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7154<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7155<p>The <tt>llvm.atomic.swap</tt> intrinsic takes two arguments. Both
7156 the <tt>val</tt> argument and the result must be integers of the same bit
7157 width. The first argument, <tt>ptr</tt>, must be a pointer to a value of this
7158 integer type. The targets may only lower integer representations they
7159 support.</p>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7160
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7161<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7162<p>This intrinsic loads the value pointed to by <tt>ptr</tt>, yields it, and
7163 stores <tt>val</tt> back into <tt>ptr</tt> atomically. This provides the
7164 equivalent of an atomic swap operation within the SSA framework.</p>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7165
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7166<h5>Examples:</h5>
7167<pre>
Victor Hernandeza70c6df2009-10-26 23:44:29 +0000[diff] [blame]7168%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7169%ptr = bitcast i8* %mallocP to i32*
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7170 store i32 4, %ptr
7171
7172%val1 = add i32 4, 4
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7173%result1 = call i32 @llvm.atomic.swap.i32.p0i32(i32* %ptr, i32 %val1)
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7174 <i>; yields {i32}:result1 = 4</i>
7175%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
7176%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
7177
7178%val2 = add i32 1, 1
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7179%result2 = call i32 @llvm.atomic.swap.i32.p0i32(i32* %ptr, i32 %val2)
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7180 <i>; yields {i32}:result2 = 8</i>
7181
7182%stored2 = icmp eq i32 %result2, 8 <i>; yields {i1}:stored2 = true</i>
7183%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 2</i>
7184</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7185
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7186</div>
7187
7188<!-- _______________________________________________________________________ -->
7189<div class="doc_subsubsection">
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7190 <a name="int_atomic_load_add">'<tt>llvm.atomic.load.add.*</tt>' Intrinsic</a>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7191
7192</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7193
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7194<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7195
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7196<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7197<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.load.add</tt> on
7198 any integer bit width. Not all targets support all bit widths however.</p>
7199
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7200<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7201 declare i8 @llvm.atomic.load.add.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7202 declare i16 @llvm.atomic.load.add.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7203 declare i32 @llvm.atomic.load.add.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7204 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]7205</pre>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7206
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7207<h5>Overview:</h5>
7208<p>This intrinsic adds <tt>delta</tt> to the value stored in memory
7209 at <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.</p>
7210
7211<h5>Arguments:</h5>
7212<p>The intrinsic takes two arguments, the first a pointer to an integer value
7213 and the second an integer value. The result is also an integer value. These
7214 integer types can have any bit width, but they must all have the same bit
7215 width. The targets may only lower integer representations they support.</p>
7216
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7217<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7218<p>This intrinsic does a series of operations atomically. It first loads the
7219 value stored at <tt>ptr</tt>. It then adds <tt>delta</tt>, stores the result
7220 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]7221
7222<h5>Examples:</h5>
7223<pre>
Victor Hernandeza70c6df2009-10-26 23:44:29 +0000[diff] [blame]7224%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7225%ptr = bitcast i8* %mallocP to i32*
7226 store i32 4, %ptr
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7227%result1 = call i32 @llvm.atomic.load.add.i32.p0i32(i32* %ptr, i32 4)
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7228 <i>; yields {i32}:result1 = 4</i>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7229%result2 = call i32 @llvm.atomic.load.add.i32.p0i32(i32* %ptr, i32 2)
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7230 <i>; yields {i32}:result2 = 8</i>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7231%result3 = call i32 @llvm.atomic.load.add.i32.p0i32(i32* %ptr, i32 5)
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7232 <i>; yields {i32}:result3 = 10</i>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7233%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 15</i>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7234</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7235
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7236</div>
7237
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7238<!-- _______________________________________________________________________ -->
7239<div class="doc_subsubsection">
7240 <a name="int_atomic_load_sub">'<tt>llvm.atomic.load.sub.*</tt>' Intrinsic</a>
7241
7242</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7243
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7244<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7245
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7246<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7247<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.load.sub</tt> on
7248 any integer bit width and for different address spaces. Not all targets
7249 support all bit widths however.</p>
7250
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7251<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7252 declare i8 @llvm.atomic.load.sub.i8.p0i32(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7253 declare i16 @llvm.atomic.load.sub.i16.p0i32(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7254 declare i32 @llvm.atomic.load.sub.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7255 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]7256</pre>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7257
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7258<h5>Overview:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]7259<p>This intrinsic subtracts <tt>delta</tt> to the value stored in memory at
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7260 <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.</p>
7261
7262<h5>Arguments:</h5>
7263<p>The intrinsic takes two arguments, the first a pointer to an integer value
7264 and the second an integer value. The result is also an integer value. These
7265 integer types can have any bit width, but they must all have the same bit
7266 width. The targets may only lower integer representations they support.</p>
7267
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7268<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7269<p>This intrinsic does a series of operations atomically. It first loads the
7270 value stored at <tt>ptr</tt>. It then subtracts <tt>delta</tt>, stores the
7271 result to <tt>ptr</tt>. It yields the original value stored
7272 at <tt>ptr</tt>.</p>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7273
7274<h5>Examples:</h5>
7275<pre>
Victor Hernandeza70c6df2009-10-26 23:44:29 +0000[diff] [blame]7276%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7277%ptr = bitcast i8* %mallocP to i32*
7278 store i32 8, %ptr
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7279%result1 = call i32 @llvm.atomic.load.sub.i32.p0i32(i32* %ptr, i32 4)
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7280 <i>; yields {i32}:result1 = 8</i>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7281%result2 = call i32 @llvm.atomic.load.sub.i32.p0i32(i32* %ptr, i32 2)
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7282 <i>; yields {i32}:result2 = 4</i>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7283%result3 = call i32 @llvm.atomic.load.sub.i32.p0i32(i32* %ptr, i32 5)
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7284 <i>; yields {i32}:result3 = 2</i>
7285%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = -3</i>
7286</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7287
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7288</div>
7289
7290<!-- _______________________________________________________________________ -->
7291<div class="doc_subsubsection">
7292 <a name="int_atomic_load_and">'<tt>llvm.atomic.load.and.*</tt>' Intrinsic</a><br>
7293 <a name="int_atomic_load_nand">'<tt>llvm.atomic.load.nand.*</tt>' Intrinsic</a><br>
7294 <a name="int_atomic_load_or">'<tt>llvm.atomic.load.or.*</tt>' Intrinsic</a><br>
7295 <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]7296</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7297
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7298<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7299
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7300<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7301<p>These are overloaded intrinsics. You can
7302 use <tt>llvm.atomic.load_and</tt>, <tt>llvm.atomic.load_nand</tt>,
7303 <tt>llvm.atomic.load_or</tt>, and <tt>llvm.atomic.load_xor</tt> on any integer
7304 bit width and for different address spaces. Not all targets support all bit
7305 widths however.</p>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7306
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7307<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7308 declare i8 @llvm.atomic.load.and.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7309 declare i16 @llvm.atomic.load.and.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7310 declare i32 @llvm.atomic.load.and.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7311 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]7312</pre>
7313
7314<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7315 declare i8 @llvm.atomic.load.or.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7316 declare i16 @llvm.atomic.load.or.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7317 declare i32 @llvm.atomic.load.or.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7318 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]7319</pre>
7320
7321<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7322 declare i8 @llvm.atomic.load.nand.i8.p0i32(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7323 declare i16 @llvm.atomic.load.nand.i16.p0i32(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7324 declare i32 @llvm.atomic.load.nand.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7325 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]7326</pre>
7327
7328<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7329 declare i8 @llvm.atomic.load.xor.i8.p0i32(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7330 declare i16 @llvm.atomic.load.xor.i16.p0i32(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7331 declare i32 @llvm.atomic.load.xor.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7332 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]7333</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7334
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7335<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7336<p>These intrinsics bitwise the operation (and, nand, or, xor) <tt>delta</tt> to
7337 the value stored in memory at <tt>ptr</tt>. It yields the original value
7338 at <tt>ptr</tt>.</p>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7339
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7340<h5>Arguments:</h5>
7341<p>These intrinsics take two arguments, the first a pointer to an integer value
7342 and the second an integer value. The result is also an integer value. These
7343 integer types can have any bit width, but they must all have the same bit
7344 width. The targets may only lower integer representations they support.</p>
7345
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7346<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7347<p>These intrinsics does a series of operations atomically. They first load the
7348 value stored at <tt>ptr</tt>. They then do the bitwise
7349 operation <tt>delta</tt>, store the result to <tt>ptr</tt>. They yield the
7350 original value stored at <tt>ptr</tt>.</p>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7351
7352<h5>Examples:</h5>
7353<pre>
Victor Hernandeza70c6df2009-10-26 23:44:29 +0000[diff] [blame]7354%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7355%ptr = bitcast i8* %mallocP to i32*
7356 store i32 0x0F0F, %ptr
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7357%result0 = call i32 @llvm.atomic.load.nand.i32.p0i32(i32* %ptr, i32 0xFF)
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7358 <i>; yields {i32}:result0 = 0x0F0F</i>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7359%result1 = call i32 @llvm.atomic.load.and.i32.p0i32(i32* %ptr, i32 0xFF)
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7360 <i>; yields {i32}:result1 = 0xFFFFFFF0</i>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7361%result2 = call i32 @llvm.atomic.load.or.i32.p0i32(i32* %ptr, i32 0F)
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7362 <i>; yields {i32}:result2 = 0xF0</i>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7363%result3 = call i32 @llvm.atomic.load.xor.i32.p0i32(i32* %ptr, i32 0F)
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7364 <i>; yields {i32}:result3 = FF</i>
7365%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = F0</i>
7366</pre>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7367
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7368</div>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7369
7370<!-- _______________________________________________________________________ -->
7371<div class="doc_subsubsection">
7372 <a name="int_atomic_load_max">'<tt>llvm.atomic.load.max.*</tt>' Intrinsic</a><br>
7373 <a name="int_atomic_load_min">'<tt>llvm.atomic.load.min.*</tt>' Intrinsic</a><br>
7374 <a name="int_atomic_load_umax">'<tt>llvm.atomic.load.umax.*</tt>' Intrinsic</a><br>
7375 <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]7376</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7377
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7378<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7379
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7380<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7381<p>These are overloaded intrinsics. You can use <tt>llvm.atomic.load_max</tt>,
7382 <tt>llvm.atomic.load_min</tt>, <tt>llvm.atomic.load_umax</tt>, and
7383 <tt>llvm.atomic.load_umin</tt> on any integer bit width and for different
7384 address spaces. Not all targets support all bit widths however.</p>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7385
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7386<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7387 declare i8 @llvm.atomic.load.max.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7388 declare i16 @llvm.atomic.load.max.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7389 declare i32 @llvm.atomic.load.max.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7390 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]7391</pre>
7392
7393<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7394 declare i8 @llvm.atomic.load.min.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7395 declare i16 @llvm.atomic.load.min.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7396 declare i32 @llvm.atomic.load.min.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7397 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]7398</pre>
7399
7400<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7401 declare i8 @llvm.atomic.load.umax.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7402 declare i16 @llvm.atomic.load.umax.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7403 declare i32 @llvm.atomic.load.umax.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7404 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]7405</pre>
7406
7407<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7408 declare i8 @llvm.atomic.load.umin.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7409 declare i16 @llvm.atomic.load.umin.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7410 declare i32 @llvm.atomic.load.umin.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7411 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]7412</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7413
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7414<h5>Overview:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]7415<p>These intrinsics takes the signed or unsigned minimum or maximum of
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7416 <tt>delta</tt> and the value stored in memory at <tt>ptr</tt>. It yields the
7417 original value at <tt>ptr</tt>.</p>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7418
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7419<h5>Arguments:</h5>
7420<p>These intrinsics take two arguments, the first a pointer to an integer value
7421 and the second an integer value. The result is also an integer value. These
7422 integer types can have any bit width, but they must all have the same bit
7423 width. The targets may only lower integer representations they support.</p>
7424
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7425<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7426<p>These intrinsics does a series of operations atomically. They first load the
7427 value stored at <tt>ptr</tt>. They then do the signed or unsigned min or
7428 max <tt>delta</tt> and the value, store the result to <tt>ptr</tt>. They
7429 yield the original value stored at <tt>ptr</tt>.</p>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7430
7431<h5>Examples:</h5>
7432<pre>
Victor Hernandeza70c6df2009-10-26 23:44:29 +0000[diff] [blame]7433%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7434%ptr = bitcast i8* %mallocP to i32*
7435 store i32 7, %ptr
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7436%result0 = call i32 @llvm.atomic.load.min.i32.p0i32(i32* %ptr, i32 -2)
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7437 <i>; yields {i32}:result0 = 7</i>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7438%result1 = call i32 @llvm.atomic.load.max.i32.p0i32(i32* %ptr, i32 8)
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7439 <i>; yields {i32}:result1 = -2</i>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7440%result2 = call i32 @llvm.atomic.load.umin.i32.p0i32(i32* %ptr, i32 10)
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7441 <i>; yields {i32}:result2 = 8</i>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7442%result3 = call i32 @llvm.atomic.load.umax.i32.p0i32(i32* %ptr, i32 30)
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7443 <i>; yields {i32}:result3 = 8</i>
7444%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 30</i>
7445</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7446
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7447</div>
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7448
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]7449
7450<!-- ======================================================================= -->
7451<div class="doc_subsection">
7452 <a name="int_memorymarkers">Memory Use Markers</a>
7453</div>
7454
7455<div class="doc_text">
7456
7457<p>This class of intrinsics exists to information about the lifetime of memory
7458 objects and ranges where variables are immutable.</p>
7459
7460</div>
7461
7462<!-- _______________________________________________________________________ -->
7463<div class="doc_subsubsection">
7464 <a name="int_lifetime_start">'<tt>llvm.lifetime.start</tt>' Intrinsic</a>
7465</div>
7466
7467<div class="doc_text">
7468
7469<h5>Syntax:</h5>
7470<pre>
7471 declare void @llvm.lifetime.start(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7472</pre>
7473
7474<h5>Overview:</h5>
7475<p>The '<tt>llvm.lifetime.start</tt>' intrinsic specifies the start of a memory
7476 object's lifetime.</p>
7477
7478<h5>Arguments:</h5>
Nick Lewycky9bc89042009-10-13 07:57:33 +0000[diff] [blame]7479<p>The first argument is a constant integer representing the size of the
7480 object, or -1 if it is variable sized. The second argument is a pointer to
7481 the object.</p>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]7482
7483<h5>Semantics:</h5>
7484<p>This intrinsic indicates that before this point in the code, the value of the
7485 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]7486 never be used and has an undefined value. A load from the pointer that
7487 precedes this intrinsic can be replaced with
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]7488 <tt>'<a href="#undefvalues">undef</a>'</tt>.</p>
7489
7490</div>
7491
7492<!-- _______________________________________________________________________ -->
7493<div class="doc_subsubsection">
7494 <a name="int_lifetime_end">'<tt>llvm.lifetime.end</tt>' Intrinsic</a>
7495</div>
7496
7497<div class="doc_text">
7498
7499<h5>Syntax:</h5>
7500<pre>
7501 declare void @llvm.lifetime.end(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7502</pre>
7503
7504<h5>Overview:</h5>
7505<p>The '<tt>llvm.lifetime.end</tt>' intrinsic specifies the end of a memory
7506 object's lifetime.</p>
7507
7508<h5>Arguments:</h5>
Nick Lewycky9bc89042009-10-13 07:57:33 +0000[diff] [blame]7509<p>The first argument is a constant integer representing the size of the
7510 object, or -1 if it is variable sized. The second argument is a pointer to
7511 the object.</p>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]7512
7513<h5>Semantics:</h5>
7514<p>This intrinsic indicates that after this point in the code, the value of the
7515 memory pointed to by <tt>ptr</tt> is dead. This means that it is known to
7516 never be used and has an undefined value. Any stores into the memory object
7517 following this intrinsic may be removed as dead.
7518
7519</div>
7520
7521<!-- _______________________________________________________________________ -->
7522<div class="doc_subsubsection">
7523 <a name="int_invariant_start">'<tt>llvm.invariant.start</tt>' Intrinsic</a>
7524</div>
7525
7526<div class="doc_text">
7527
7528<h5>Syntax:</h5>
7529<pre>
Nick Lewycky2965d3e2010-11-30 04:13:41 +0000[diff] [blame]7530 declare {}* @llvm.invariant.start(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]7531</pre>
7532
7533<h5>Overview:</h5>
7534<p>The '<tt>llvm.invariant.start</tt>' intrinsic specifies that the contents of
7535 a memory object will not change.</p>
7536
7537<h5>Arguments:</h5>
Nick Lewycky9bc89042009-10-13 07:57:33 +0000[diff] [blame]7538<p>The first argument is a constant integer representing the size of the
7539 object, or -1 if it is variable sized. The second argument is a pointer to
7540 the object.</p>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]7541
7542<h5>Semantics:</h5>
7543<p>This intrinsic indicates that until an <tt>llvm.invariant.end</tt> that uses
7544 the return value, the referenced memory location is constant and
7545 unchanging.</p>
7546
7547</div>
7548
7549<!-- _______________________________________________________________________ -->
7550<div class="doc_subsubsection">
7551 <a name="int_invariant_end">'<tt>llvm.invariant.end</tt>' Intrinsic</a>
7552</div>
7553
7554<div class="doc_text">
7555
7556<h5>Syntax:</h5>
7557<pre>
7558 declare void @llvm.invariant.end({}* &lt;start&gt;, i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7559</pre>
7560
7561<h5>Overview:</h5>
7562<p>The '<tt>llvm.invariant.end</tt>' intrinsic specifies that the contents of
7563 a memory object are mutable.</p>
7564
7565<h5>Arguments:</h5>
7566<p>The first argument is the matching <tt>llvm.invariant.start</tt> intrinsic.
Nick Lewycky9bc89042009-10-13 07:57:33 +0000[diff] [blame]7567 The second argument is a constant integer representing the size of the
7568 object, or -1 if it is variable sized and the third argument is a pointer
7569 to the object.</p>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]7570
7571<h5>Semantics:</h5>
7572<p>This intrinsic indicates that the memory is mutable again.</p>
7573
7574</div>
7575
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7576<!-- ======================================================================= -->
7577<div class="doc_subsection">
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]7578 <a name="int_general">General Intrinsics</a>
7579</div>
7580
7581<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7582
7583<p>This class of intrinsics is designed to be generic and has no specific
7584 purpose.</p>
7585
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]7586</div>
7587
7588<!-- _______________________________________________________________________ -->
7589<div class="doc_subsubsection">
7590 <a name="int_var_annotation">'<tt>llvm.var.annotation</tt>' Intrinsic</a>
7591</div>
7592
7593<div class="doc_text">
7594
7595<h5>Syntax:</h5>
7596<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7597 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]7598</pre>
7599
7600<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7601<p>The '<tt>llvm.var.annotation</tt>' intrinsic.</p>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]7602
7603<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7604<p>The first argument is a pointer to a value, the second is a pointer to a
7605 global string, the third is a pointer to a global string which is the source
7606 file name, and the last argument is the line number.</p>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]7607
7608<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7609<p>This intrinsic allows annotation of local variables with arbitrary strings.
7610 This can be useful for special purpose optimizations that want to look for
7611 these annotations. These have no other defined use, they are ignored by code
7612 generation and optimization.</p>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]7613
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]7614</div>
7615
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]7616<!-- _______________________________________________________________________ -->
7617<div class="doc_subsubsection">
Tanya Lattner0186a652007-09-21 23:57:59 +0000[diff] [blame]7618 <a name="int_annotation">'<tt>llvm.annotation.*</tt>' Intrinsic</a>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]7619</div>
7620
7621<div class="doc_text">
7622
7623<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7624<p>This is an overloaded intrinsic. You can use '<tt>llvm.annotation</tt>' on
7625 any integer bit width.</p>
7626
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]7627<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7628 declare i8 @llvm.annotation.i8(i8 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
7629 declare i16 @llvm.annotation.i16(i16 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
7630 declare i32 @llvm.annotation.i32(i32 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
7631 declare i64 @llvm.annotation.i64(i64 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
7632 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]7633</pre>
7634
7635<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7636<p>The '<tt>llvm.annotation</tt>' intrinsic.</p>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]7637
7638<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7639<p>The first argument is an integer value (result of some expression), the
7640 second is a pointer to a global string, the third is a pointer to a global
7641 string which is the source file name, and the last argument is the line
7642 number. It returns the value of the first argument.</p>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]7643
7644<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7645<p>This intrinsic allows annotations to be put on arbitrary expressions with
7646 arbitrary strings. This can be useful for special purpose optimizations that
7647 want to look for these annotations. These have no other defined use, they
7648 are ignored by code generation and optimization.</p>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]7649
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]7650</div>
Jim Laskey2211f492007-03-14 19:31:19 +0000[diff] [blame]7651
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]7652<!-- _______________________________________________________________________ -->
7653<div class="doc_subsubsection">
7654 <a name="int_trap">'<tt>llvm.trap</tt>' Intrinsic</a>
7655</div>
7656
7657<div class="doc_text">
7658
7659<h5>Syntax:</h5>
7660<pre>
7661 declare void @llvm.trap()
7662</pre>
7663
7664<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7665<p>The '<tt>llvm.trap</tt>' intrinsic.</p>
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]7666
7667<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7668<p>None.</p>
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]7669
7670<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7671<p>This intrinsics is lowered to the target dependent trap instruction. If the
7672 target does not have a trap instruction, this intrinsic will be lowered to
7673 the call of the <tt>abort()</tt> function.</p>
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]7674
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]7675</div>
7676
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]7677<!-- _______________________________________________________________________ -->
7678<div class="doc_subsubsection">
Misha Brukman50de2b22008-11-22 23:55:29 +0000[diff] [blame]7679 <a name="int_stackprotector">'<tt>llvm.stackprotector</tt>' Intrinsic</a>
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]7680</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7681
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]7682<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7683
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]7684<h5>Syntax:</h5>
7685<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7686 declare void @llvm.stackprotector(i8* &lt;guard&gt;, i8** &lt;slot&gt;)
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]7687</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7688
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]7689<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7690<p>The <tt>llvm.stackprotector</tt> intrinsic takes the <tt>guard</tt> and
7691 stores it onto the stack at <tt>slot</tt>. The stack slot is adjusted to
7692 ensure that it is placed on the stack before local variables.</p>
7693
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]7694<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7695<p>The <tt>llvm.stackprotector</tt> intrinsic requires two pointer
7696 arguments. The first argument is the value loaded from the stack
7697 guard <tt>@__stack_chk_guard</tt>. The second variable is an <tt>alloca</tt>
7698 that has enough space to hold the value of the guard.</p>
7699
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]7700<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7701<p>This intrinsic causes the prologue/epilogue inserter to force the position of
7702 the <tt>AllocaInst</tt> stack slot to be before local variables on the
7703 stack. This is to ensure that if a local variable on the stack is
7704 overwritten, it will destroy the value of the guard. When the function exits,
Bill Wendling6bbe0912010-10-27 01:07:41 +0000[diff] [blame]7705 the guard on the stack is checked against the original guard. If they are
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7706 different, then the program aborts by calling the <tt>__stack_chk_fail()</tt>
7707 function.</p>
7708
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]7709</div>
7710
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]7711<!-- _______________________________________________________________________ -->
7712<div class="doc_subsubsection">
7713 <a name="int_objectsize">'<tt>llvm.objectsize</tt>' Intrinsic</a>
7714</div>
7715
7716<div class="doc_text">
7717
7718<h5>Syntax:</h5>
7719<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7720 declare i32 @llvm.objectsize.i32(i8* &lt;object&gt;, i1 &lt;type&gt;)
7721 declare i64 @llvm.objectsize.i64(i8* &lt;object&gt;, i1 &lt;type&gt;)
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]7722</pre>
7723
7724<h5>Overview:</h5>
Bill Wendling6bbe0912010-10-27 01:07:41 +0000[diff] [blame]7725<p>The <tt>llvm.objectsize</tt> intrinsic is designed to provide information to
7726 the optimizers to determine at compile time whether a) an operation (like
7727 memcpy) will overflow a buffer that corresponds to an object, or b) that a
7728 runtime check for overflow isn't necessary. An object in this context means
7729 an allocation of a specific class, structure, array, or other object.</p>
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]7730
7731<h5>Arguments:</h5>
Bill Wendling6bbe0912010-10-27 01:07:41 +0000[diff] [blame]7732<p>The <tt>llvm.objectsize</tt> intrinsic takes two arguments. The first
Eric Christopher31e39bd2009-12-23 00:29:49 +0000[diff] [blame]7733 argument is a pointer to or into the <tt>object</tt>. The second argument
Bill Wendling6bbe0912010-10-27 01:07:41 +0000[diff] [blame]7734 is a boolean 0 or 1. This argument determines whether you want the
7735 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]7736 1, variables are not allowed.</p>
7737
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]7738<h5>Semantics:</h5>
7739<p>The <tt>llvm.objectsize</tt> intrinsic is lowered to either a constant
Bill Wendling6bbe0912010-10-27 01:07:41 +0000[diff] [blame]7740 representing the size of the object concerned, or <tt>i32/i64 -1 or 0</tt>,
7741 depending on the <tt>type</tt> argument, if the size cannot be determined at
7742 compile time.</p>
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]7743
7744</div>
7745
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]7746<!-- *********************************************************************** -->
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]7747<hr>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]7748<address>
7749 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
Misha Brukman86242e12008-12-11 17:34:48 +0000[diff] [blame]7750 src="http://jigsaw.w3.org/css-validator/images/vcss-blue" alt="Valid CSS"></a>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]7751 <a href="http://validator.w3.org/check/referer"><img
Misha Brukman86242e12008-12-11 17:34:48 +0000[diff] [blame]7752 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]7753
7754 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
Reid Spencerca058542006-03-14 05:39:39 +0000[diff] [blame]7755 <a href="http://llvm.org">The LLVM Compiler Infrastructure</a><br>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]7756 Last modified: $Date$
7757</address>
Chris Lattnerb8f816e2008-01-04 04:33:49 +0000[diff] [blame]7758
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]7759</body>
7760</html>