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gerrit-public.fairphone.software / toolchain / llvm-project / b1f0ff1d66361f452538f146b25a133fc30d1e32 / . / 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;
496<a href="#identifiers">@.LC0</a> = <a href="#linkage_internal">internal</a> <a href="#globalvars">constant</a> <a href="#t_array">[13 x i8]</a> c"hello world\0A\00" <i>; [13 x i8]*</i>&nbsp;
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]497
Chris Lattner54a7be72010-08-17 17:13:42 +0000[diff] [blame]498<i>; External declaration of the puts function</i>&nbsp;
499<a href="#functionstructure">declare</a> i32 @puts(i8*) <i>; i32 (i8*)* </i>&nbsp;
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]500
501<i>; Definition of main function</i>
Chris Lattner54a7be72010-08-17 17:13:42 +0000[diff] [blame]502define i32 @main() { <i>; i32()* </i>&nbsp;
503 <i>; Convert [13 x i8]* to i8 *...</i>&nbsp;
504 %cast210 = <a href="#i_getelementptr">getelementptr</a> [13 x i8]* @.LC0, i64 0, i64 0 <i>; i8*</i>&nbsp;
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]505
Chris Lattner54a7be72010-08-17 17:13:42 +0000[diff] [blame]506 <i>; Call puts function to write out the string to stdout.</i>&nbsp;
507 <a href="#i_call">call</a> i32 @puts(i8* %cast210) <i>; i32</i>&nbsp;
508 <a href="#i_ret">ret</a> i32 0&nbsp;
509}
Devang Pateld1a89692010-01-11 19:35:55 +0000[diff] [blame]510
511<i>; Named metadata</i>
512!1 = metadata !{i32 41}
513!foo = !{!1, null}
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]514</pre>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]515
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]516<p>This example is made up of a <a href="#globalvars">global variable</a> named
Devang Pateld1a89692010-01-11 19:35:55 +0000[diff] [blame]517 "<tt>.LC0</tt>", an external declaration of the "<tt>puts</tt>" function,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]518 a <a href="#functionstructure">function definition</a> for
Devang Pateld1a89692010-01-11 19:35:55 +0000[diff] [blame]519 "<tt>main</tt>" and <a href="#namedmetadatastructure">named metadata</a>
520 "<tt>foo"</tt>.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]521
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]522<p>In general, a module is made up of a list of global values, where both
523 functions and global variables are global values. Global values are
524 represented by a pointer to a memory location (in this case, a pointer to an
525 array of char, and a pointer to a function), and have one of the
526 following <a href="#linkage">linkage types</a>.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]527
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]528</div>
529
530<!-- ======================================================================= -->
531<div class="doc_subsection">
532 <a name="linkage">Linkage Types</a>
533</div>
534
535<div class="doc_text">
536
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]537<p>All Global Variables and Functions have one of the following types of
538 linkage:</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]539
540<dl>
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]541 <dt><tt><b><a name="linkage_private">private</a></b></tt></dt>
Bill Wendling03bcd6e2010-07-01 21:55:59 +0000[diff] [blame]542 <dd>Global values with "<tt>private</tt>" linkage are only directly accessible
543 by objects in the current module. In particular, linking code into a
544 module with an private global value may cause the private to be renamed as
545 necessary to avoid collisions. Because the symbol is private to the
546 module, all references can be updated. This doesn't show up in any symbol
547 table in the object file.</dd>
Rafael Espindola6de96a12009-01-15 20:18:42 +0000[diff] [blame]548
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]549 <dt><tt><b><a name="linkage_linker_private">linker_private</a></b></tt></dt>
Bill Wendling03bcd6e2010-07-01 21:55:59 +0000[diff] [blame]550 <dd>Similar to <tt>private</tt>, but the symbol is passed through the
551 assembler and evaluated by the linker. Unlike normal strong symbols, they
552 are removed by the linker from the final linked image (executable or
553 dynamic library).</dd>
554
555 <dt><tt><b><a name="linkage_linker_private_weak">linker_private_weak</a></b></tt></dt>
556 <dd>Similar to "<tt>linker_private</tt>", but the symbol is weak. Note that
557 <tt>linker_private_weak</tt> symbols are subject to coalescing by the
558 linker. The symbols are removed by the linker from the final linked image
559 (executable or dynamic library).</dd>
Bill Wendlinga3c6f6b2009-07-20 01:03:30 +0000[diff] [blame]560
Bill Wendling578ee402010-08-20 22:05:50 +0000[diff] [blame]561 <dt><tt><b><a name="linkage_linker_private_weak_def_auto">linker_private_weak_def_auto</a></b></tt></dt>
562 <dd>Similar to "<tt>linker_private_weak</tt>", but it's known that the address
563 of the object is not taken. For instance, functions that had an inline
564 definition, but the compiler decided not to inline it. Note,
565 unlike <tt>linker_private</tt> and <tt>linker_private_weak</tt>,
566 <tt>linker_private_weak_def_auto</tt> may have only <tt>default</tt>
567 visibility. The symbols are removed by the linker from the final linked
568 image (executable or dynamic library).</dd>
569
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]570 <dt><tt><b><a name="linkage_internal">internal</a></b></tt></dt>
Bill Wendling36321712010-06-29 22:34:52 +0000[diff] [blame]571 <dd>Similar to private, but the value shows as a local symbol
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]572 (<tt>STB_LOCAL</tt> in the case of ELF) in the object file. This
573 corresponds to the notion of the '<tt>static</tt>' keyword in C.</dd>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]574
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]575 <dt><tt><b><a name="linkage_available_externally">available_externally</a></b></tt></dt>
Chris Lattner184f1be2009-04-13 05:44:34 +0000[diff] [blame]576 <dd>Globals with "<tt>available_externally</tt>" linkage are never emitted
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]577 into the object file corresponding to the LLVM module. They exist to
578 allow inlining and other optimizations to take place given knowledge of
579 the definition of the global, which is known to be somewhere outside the
580 module. Globals with <tt>available_externally</tt> linkage are allowed to
581 be discarded at will, and are otherwise the same as <tt>linkonce_odr</tt>.
582 This linkage type is only allowed on definitions, not declarations.</dd>
Chris Lattner184f1be2009-04-13 05:44:34 +0000[diff] [blame]583
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]584 <dt><tt><b><a name="linkage_linkonce">linkonce</a></b></tt></dt>
Chris Lattnere20b4702007-01-14 06:51:48 +0000[diff] [blame]585 <dd>Globals with "<tt>linkonce</tt>" linkage are merged with other globals of
Chris Lattner0de4caa2010-01-09 19:15:14 +0000[diff] [blame]586 the same name when linkage occurs. This can be used to implement
587 some forms of inline functions, templates, or other code which must be
588 generated in each translation unit that uses it, but where the body may
589 be overridden with a more definitive definition later. Unreferenced
590 <tt>linkonce</tt> globals are allowed to be discarded. Note that
591 <tt>linkonce</tt> linkage does not actually allow the optimizer to
592 inline the body of this function into callers because it doesn't know if
593 this definition of the function is the definitive definition within the
594 program or whether it will be overridden by a stronger definition.
595 To enable inlining and other optimizations, use "<tt>linkonce_odr</tt>"
596 linkage.</dd>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]597
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]598 <dt><tt><b><a name="linkage_weak">weak</a></b></tt></dt>
Chris Lattnerd0554882009-08-05 05:21:07 +0000[diff] [blame]599 <dd>"<tt>weak</tt>" linkage has the same merging semantics as
600 <tt>linkonce</tt> linkage, except that unreferenced globals with
601 <tt>weak</tt> linkage may not be discarded. This is used for globals that
602 are declared "weak" in C source code.</dd>
603
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]604 <dt><tt><b><a name="linkage_common">common</a></b></tt></dt>
Chris Lattnerd0554882009-08-05 05:21:07 +0000[diff] [blame]605 <dd>"<tt>common</tt>" linkage is most similar to "<tt>weak</tt>" linkage, but
606 they are used for tentative definitions in C, such as "<tt>int X;</tt>" at
607 global scope.
608 Symbols with "<tt>common</tt>" linkage are merged in the same way as
609 <tt>weak symbols</tt>, and they may not be deleted if unreferenced.
Chris Lattner0aff0b22009-08-05 05:41:44 +0000[diff] [blame]610 <tt>common</tt> symbols may not have an explicit section,
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]611 must have a zero initializer, and may not be marked '<a
Chris Lattner0aff0b22009-08-05 05:41:44 +0000[diff] [blame]612 href="#globalvars"><tt>constant</tt></a>'. Functions and aliases may not
613 have common linkage.</dd>
Chris Lattnerd0554882009-08-05 05:21:07 +0000[diff] [blame]614
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]615
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]616 <dt><tt><b><a name="linkage_appending">appending</a></b></tt></dt>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]617 <dd>"<tt>appending</tt>" linkage may only be applied to global variables of
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]618 pointer to array type. When two global variables with appending linkage
619 are linked together, the two global arrays are appended together. This is
620 the LLVM, typesafe, equivalent of having the system linker append together
621 "sections" with identical names when .o files are linked.</dd>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]622
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]623 <dt><tt><b><a name="linkage_externweak">extern_weak</a></b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]624 <dd>The semantics of this linkage follow the ELF object file model: the symbol
625 is weak until linked, if not linked, the symbol becomes null instead of
626 being an undefined reference.</dd>
Anton Korobeynikova0554d92007-01-12 19:20:47 +0000[diff] [blame]627
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]628 <dt><tt><b><a name="linkage_linkonce_odr">linkonce_odr</a></b></tt></dt>
629 <dt><tt><b><a name="linkage_weak_odr">weak_odr</a></b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]630 <dd>Some languages allow differing globals to be merged, such as two functions
631 with different semantics. Other languages, such as <tt>C++</tt>, ensure
Bill Wendling03bcd6e2010-07-01 21:55:59 +0000[diff] [blame]632 that only equivalent globals are ever merged (the "one definition rule"
633 &mdash; "ODR"). Such languages can use the <tt>linkonce_odr</tt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]634 and <tt>weak_odr</tt> linkage types to indicate that the global will only
635 be merged with equivalent globals. These linkage types are otherwise the
636 same as their non-<tt>odr</tt> versions.</dd>
Duncan Sands12da8ce2009-03-07 15:45:40 +0000[diff] [blame]637
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]638 <dt><tt><b><a name="linkage_external">externally visible</a></b></tt>:</dt>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]639 <dd>If none of the above identifiers are used, the global is externally
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]640 visible, meaning that it participates in linkage and can be used to
641 resolve external symbol references.</dd>
Reid Spencer7972c472007-04-11 23:49:50 +0000[diff] [blame]642</dl>
Anton Korobeynikovd61d39e2006-09-14 18:23:27 +0000[diff] [blame]643
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]644<p>The next two types of linkage are targeted for Microsoft Windows platform
645 only. They are designed to support importing (exporting) symbols from (to)
646 DLLs (Dynamic Link Libraries).</p>
Anton Korobeynikovd61d39e2006-09-14 18:23:27 +0000[diff] [blame]647
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]648<dl>
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]649 <dt><tt><b><a name="linkage_dllimport">dllimport</a></b></tt></dt>
Anton Korobeynikovd61d39e2006-09-14 18:23:27 +0000[diff] [blame]650 <dd>"<tt>dllimport</tt>" linkage causes the compiler to reference a function
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]651 or variable via a global pointer to a pointer that is set up by the DLL
652 exporting the symbol. On Microsoft Windows targets, the pointer name is
653 formed by combining <code>__imp_</code> and the function or variable
654 name.</dd>
Anton Korobeynikovd61d39e2006-09-14 18:23:27 +0000[diff] [blame]655
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]656 <dt><tt><b><a name="linkage_dllexport">dllexport</a></b></tt></dt>
Anton Korobeynikovd61d39e2006-09-14 18:23:27 +0000[diff] [blame]657 <dd>"<tt>dllexport</tt>" linkage causes the compiler to provide a global
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]658 pointer to a pointer in a DLL, so that it can be referenced with the
659 <tt>dllimport</tt> attribute. On Microsoft Windows targets, the pointer
660 name is formed by combining <code>__imp_</code> and the function or
661 variable name.</dd>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]662</dl>
663
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]664<p>For example, since the "<tt>.LC0</tt>" variable is defined to be internal, if
665 another module defined a "<tt>.LC0</tt>" variable and was linked with this
666 one, one of the two would be renamed, preventing a collision. Since
667 "<tt>main</tt>" and "<tt>puts</tt>" are external (i.e., lacking any linkage
668 declarations), they are accessible outside of the current module.</p>
669
670<p>It is illegal for a function <i>declaration</i> to have any linkage type
671 other than "externally visible", <tt>dllimport</tt>
672 or <tt>extern_weak</tt>.</p>
673
Duncan Sands12da8ce2009-03-07 15:45:40 +0000[diff] [blame]674<p>Aliases can have only <tt>external</tt>, <tt>internal</tt>, <tt>weak</tt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]675 or <tt>weak_odr</tt> linkages.</p>
676
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]677</div>
678
679<!-- ======================================================================= -->
680<div class="doc_subsection">
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]681 <a name="callingconv">Calling Conventions</a>
682</div>
683
684<div class="doc_text">
685
686<p>LLVM <a href="#functionstructure">functions</a>, <a href="#i_call">calls</a>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]687 and <a href="#i_invoke">invokes</a> can all have an optional calling
688 convention specified for the call. The calling convention of any pair of
689 dynamic caller/callee must match, or the behavior of the program is
690 undefined. The following calling conventions are supported by LLVM, and more
691 may be added in the future:</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]692
693<dl>
694 <dt><b>"<tt>ccc</tt>" - The C calling convention</b>:</dt>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]695 <dd>This calling convention (the default if no other calling convention is
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]696 specified) matches the target C calling conventions. This calling
697 convention supports varargs function calls and tolerates some mismatch in
698 the declared prototype and implemented declaration of the function (as
699 does normal C).</dd>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]700
701 <dt><b>"<tt>fastcc</tt>" - The fast calling convention</b>:</dt>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]702 <dd>This calling convention attempts to make calls as fast as possible
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]703 (e.g. by passing things in registers). This calling convention allows the
704 target to use whatever tricks it wants to produce fast code for the
705 target, without having to conform to an externally specified ABI
Jeffrey Yasskinb8677462010-01-09 19:44:16 +0000[diff] [blame]706 (Application Binary Interface).
707 <a href="CodeGenerator.html#tailcallopt">Tail calls can only be optimized
Chris Lattnera179e4d2010-03-11 00:22:57 +0000[diff] [blame]708 when this or the GHC convention is used.</a> This calling convention
709 does not support varargs and requires the prototype of all callees to
710 exactly match the prototype of the function definition.</dd>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]711
712 <dt><b>"<tt>coldcc</tt>" - The cold calling convention</b>:</dt>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]713 <dd>This calling convention attempts to make code in the caller as efficient
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]714 as possible under the assumption that the call is not commonly executed.
715 As such, these calls often preserve all registers so that the call does
716 not break any live ranges in the caller side. This calling convention
717 does not support varargs and requires the prototype of all callees to
718 exactly match the prototype of the function definition.</dd>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]719
Chris Lattnera179e4d2010-03-11 00:22:57 +0000[diff] [blame]720 <dt><b>"<tt>cc <em>10</em></tt>" - GHC convention</b>:</dt>
721 <dd>This calling convention has been implemented specifically for use by the
722 <a href="http://www.haskell.org/ghc">Glasgow Haskell Compiler (GHC)</a>.
723 It passes everything in registers, going to extremes to achieve this by
724 disabling callee save registers. This calling convention should not be
725 used lightly but only for specific situations such as an alternative to
726 the <em>register pinning</em> performance technique often used when
727 implementing functional programming languages.At the moment only X86
728 supports this convention and it has the following limitations:
729 <ul>
730 <li>On <em>X86-32</em> only supports up to 4 bit type parameters. No
731 floating point types are supported.</li>
732 <li>On <em>X86-64</em> only supports up to 10 bit type parameters and
733 6 floating point parameters.</li>
734 </ul>
735 This calling convention supports
736 <a href="CodeGenerator.html#tailcallopt">tail call optimization</a> but
737 requires both the caller and callee are using it.
738 </dd>
739
Chris Lattner573f64e2005-05-07 01:46:40 +0000[diff] [blame]740 <dt><b>"<tt>cc &lt;<em>n</em>&gt;</tt>" - Numbered convention</b>:</dt>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]741 <dd>Any calling convention may be specified by number, allowing
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]742 target-specific calling conventions to be used. Target specific calling
743 conventions start at 64.</dd>
Chris Lattner573f64e2005-05-07 01:46:40 +0000[diff] [blame]744</dl>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]745
746<p>More calling conventions can be added/defined on an as-needed basis, to
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]747 support Pascal conventions or any other well-known target-independent
748 convention.</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]749
750</div>
751
752<!-- ======================================================================= -->
753<div class="doc_subsection">
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]754 <a name="visibility">Visibility Styles</a>
755</div>
756
757<div class="doc_text">
758
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]759<p>All Global Variables and Functions have one of the following visibility
760 styles:</p>
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]761
762<dl>
763 <dt><b>"<tt>default</tt>" - Default style</b>:</dt>
Chris Lattner67c37d12008-08-05 18:29:16 +0000[diff] [blame]764 <dd>On targets that use the ELF object file format, default visibility means
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]765 that the declaration is visible to other modules and, in shared libraries,
766 means that the declared entity may be overridden. On Darwin, default
767 visibility means that the declaration is visible to other modules. Default
768 visibility corresponds to "external linkage" in the language.</dd>
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]769
770 <dt><b>"<tt>hidden</tt>" - Hidden style</b>:</dt>
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]771 <dd>Two declarations of an object with hidden visibility refer to the same
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]772 object if they are in the same shared object. Usually, hidden visibility
773 indicates that the symbol will not be placed into the dynamic symbol
774 table, so no other module (executable or shared library) can reference it
775 directly.</dd>
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]776
Anton Korobeynikov39f3cff2007-04-29 18:35:00 +0000[diff] [blame]777 <dt><b>"<tt>protected</tt>" - Protected style</b>:</dt>
Anton Korobeynikov39f3cff2007-04-29 18:35:00 +0000[diff] [blame]778 <dd>On ELF, protected visibility indicates that the symbol will be placed in
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]779 the dynamic symbol table, but that references within the defining module
780 will bind to the local symbol. That is, the symbol cannot be overridden by
781 another module.</dd>
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]782</dl>
783
784</div>
785
786<!-- ======================================================================= -->
787<div class="doc_subsection">
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]788 <a name="namedtypes">Named Types</a>
789</div>
790
791<div class="doc_text">
792
793<p>LLVM IR allows you to specify name aliases for certain types. This can make
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]794 it easier to read the IR and make the IR more condensed (particularly when
795 recursive types are involved). An example of a name specification is:</p>
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]796
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]797<pre class="doc_code">
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]798%mytype = type { %mytype*, i32 }
799</pre>
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]800
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]801<p>You may give a name to any <a href="#typesystem">type</a> except
Chris Lattner249b9762010-08-17 23:26:04 +0000[diff] [blame]802 "<a href="#t_void">void</a>". Type name aliases may be used anywhere a type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]803 is expected with the syntax "%mytype".</p>
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]804
805<p>Note that type names are aliases for the structural type that they indicate,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]806 and that you can therefore specify multiple names for the same type. This
807 often leads to confusing behavior when dumping out a .ll file. Since LLVM IR
808 uses structural typing, the name is not part of the type. When printing out
809 LLVM IR, the printer will pick <em>one name</em> to render all types of a
810 particular shape. This means that if you have code where two different
811 source types end up having the same LLVM type, that the dumper will sometimes
812 print the "wrong" or unexpected type. This is an important design point and
813 isn't going to change.</p>
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]814
815</div>
816
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]817<!-- ======================================================================= -->
818<div class="doc_subsection">
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]819 <a name="globalvars">Global Variables</a>
820</div>
821
822<div class="doc_text">
823
Chris Lattner5d5aede2005-02-12 19:30:21 +0000[diff] [blame]824<p>Global variables define regions of memory allocated at compilation time
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]825 instead of run-time. Global variables may optionally be initialized, may
826 have an explicit section to be placed in, and may have an optional explicit
827 alignment specified. A variable may be defined as "thread_local", which
828 means that it will not be shared by threads (each thread will have a
829 separated copy of the variable). A variable may be defined as a global
830 "constant," which indicates that the contents of the variable
831 will <b>never</b> be modified (enabling better optimization, allowing the
832 global data to be placed in the read-only section of an executable, etc).
833 Note that variables that need runtime initialization cannot be marked
834 "constant" as there is a store to the variable.</p>
Chris Lattner5d5aede2005-02-12 19:30:21 +0000[diff] [blame]835
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]836<p>LLVM explicitly allows <em>declarations</em> of global variables to be marked
837 constant, even if the final definition of the global is not. This capability
838 can be used to enable slightly better optimization of the program, but
839 requires the language definition to guarantee that optimizations based on the
840 'constantness' are valid for the translation units that do not include the
841 definition.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]842
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]843<p>As SSA values, global variables define pointer values that are in scope
844 (i.e. they dominate) all basic blocks in the program. Global variables
845 always define a pointer to their "content" type because they describe a
846 region of memory, and all memory objects in LLVM are accessed through
847 pointers.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]848
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]849<p>A global variable may be declared to reside in a target-specific numbered
850 address space. For targets that support them, address spaces may affect how
851 optimizations are performed and/or what target instructions are used to
852 access the variable. The default address space is zero. The address space
853 qualifier must precede any other attributes.</p>
Christopher Lamb308121c2007-12-11 09:31:00 +0000[diff] [blame]854
Chris Lattner662c8722005-11-12 00:45:07 +0000[diff] [blame]855<p>LLVM allows an explicit section to be specified for globals. If the target
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]856 supports it, it will emit globals to the section specified.</p>
Chris Lattner662c8722005-11-12 00:45:07 +0000[diff] [blame]857
Chris Lattner78e00bc2010-04-28 00:13:42 +0000[diff] [blame]858<p>An explicit alignment may be specified for a global, which must be a power
859 of 2. If not present, or if the alignment is set to zero, the alignment of
860 the global is set by the target to whatever it feels convenient. If an
861 explicit alignment is specified, the global is forced to have exactly that
Chris Lattner4bd85e42010-04-28 00:31:12 +0000[diff] [blame]862 alignment. Targets and optimizers are not allowed to over-align the global
863 if the global has an assigned section. In this case, the extra alignment
864 could be observable: for example, code could assume that the globals are
865 densely packed in their section and try to iterate over them as an array,
866 alignment padding would break this iteration.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]867
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]868<p>For example, the following defines a global in a numbered address space with
869 an initializer, section, and alignment:</p>
Chris Lattner5760c502007-01-14 00:27:09 +0000[diff] [blame]870
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]871<pre class="doc_code">
Dan Gohmanaaa679b2009-01-11 00:40:00 +0000[diff] [blame]872@G = addrspace(5) constant float 1.0, section "foo", align 4
Chris Lattner5760c502007-01-14 00:27:09 +0000[diff] [blame]873</pre>
874
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]875</div>
876
877
878<!-- ======================================================================= -->
879<div class="doc_subsection">
880 <a name="functionstructure">Functions</a>
881</div>
882
883<div class="doc_text">
884
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]885<p>LLVM function definitions consist of the "<tt>define</tt>" keyword, an
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]886 optional <a href="#linkage">linkage type</a>, an optional
887 <a href="#visibility">visibility style</a>, an optional
888 <a href="#callingconv">calling convention</a>, a return type, an optional
889 <a href="#paramattrs">parameter attribute</a> for the return type, a function
890 name, a (possibly empty) argument list (each with optional
891 <a href="#paramattrs">parameter attributes</a>), optional
892 <a href="#fnattrs">function attributes</a>, an optional section, an optional
893 alignment, an optional <a href="#gc">garbage collector name</a>, an opening
894 curly brace, a list of basic blocks, and a closing curly brace.</p>
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]895
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]896<p>LLVM function declarations consist of the "<tt>declare</tt>" keyword, an
897 optional <a href="#linkage">linkage type</a>, an optional
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]898 <a href="#visibility">visibility style</a>, an optional
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]899 <a href="#callingconv">calling convention</a>, a return type, an optional
900 <a href="#paramattrs">parameter attribute</a> for the return type, a function
901 name, a possibly empty list of arguments, an optional alignment, and an
902 optional <a href="#gc">garbage collector name</a>.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]903
Chris Lattner67c37d12008-08-05 18:29:16 +0000[diff] [blame]904<p>A function definition contains a list of basic blocks, forming the CFG
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]905 (Control Flow Graph) for the function. Each basic block may optionally start
906 with a label (giving the basic block a symbol table entry), contains a list
907 of instructions, and ends with a <a href="#terminators">terminator</a>
908 instruction (such as a branch or function return).</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]909
Chris Lattnera59fb102007-06-08 16:52:14 +0000[diff] [blame]910<p>The first basic block in a function is special in two ways: it is immediately
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]911 executed on entrance to the function, and it is not allowed to have
912 predecessor basic blocks (i.e. there can not be any branches to the entry
913 block of a function). Because the block can have no predecessors, it also
914 cannot have any <a href="#i_phi">PHI nodes</a>.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]915
Chris Lattner662c8722005-11-12 00:45:07 +0000[diff] [blame]916<p>LLVM allows an explicit section to be specified for functions. If the target
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]917 supports it, it will emit functions to the section specified.</p>
Chris Lattner662c8722005-11-12 00:45:07 +0000[diff] [blame]918
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]919<p>An explicit alignment may be specified for a function. If not present, or if
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]920 the alignment is set to zero, the alignment of the function is set by the
921 target to whatever it feels convenient. If an explicit alignment is
922 specified, the function is forced to have at least that much alignment. All
923 alignments must be a power of 2.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]924
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]925<h5>Syntax:</h5>
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]926<pre class="doc_code">
Chris Lattner0ae02092008-10-13 16:55:18 +0000[diff] [blame]927define [<a href="#linkage">linkage</a>] [<a href="#visibility">visibility</a>]
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]928 [<a href="#callingconv">cconv</a>] [<a href="#paramattrs">ret attrs</a>]
929 &lt;ResultType&gt; @&lt;FunctionName&gt; ([argument list])
930 [<a href="#fnattrs">fn Attrs</a>] [section "name"] [align N]
931 [<a href="#gc">gc</a>] { ... }
932</pre>
Devang Patel02256232008-10-07 17:48:33 +0000[diff] [blame]933
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]934</div>
935
Anton Korobeynikova97b6942007-04-25 14:27:10 +0000[diff] [blame]936<!-- ======================================================================= -->
937<div class="doc_subsection">
938 <a name="aliasstructure">Aliases</a>
939</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]940
Anton Korobeynikova97b6942007-04-25 14:27:10 +0000[diff] [blame]941<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]942
943<p>Aliases act as "second name" for the aliasee value (which can be either
944 function, global variable, another alias or bitcast of global value). Aliases
945 may have an optional <a href="#linkage">linkage type</a>, and an
946 optional <a href="#visibility">visibility style</a>.</p>
Anton Korobeynikova97b6942007-04-25 14:27:10 +0000[diff] [blame]947
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]948<h5>Syntax:</h5>
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]949<pre class="doc_code">
Duncan Sands7e99a942008-09-12 20:48:21 +0000[diff] [blame]950@&lt;Name&gt; = alias [Linkage] [Visibility] &lt;AliaseeTy&gt; @&lt;Aliasee&gt;
Bill Wendling2d8b9a82007-05-29 09:42:13 +0000[diff] [blame]951</pre>
Anton Korobeynikova97b6942007-04-25 14:27:10 +0000[diff] [blame]952
953</div>
954
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]955<!-- ======================================================================= -->
Devang Pateld1a89692010-01-11 19:35:55 +0000[diff] [blame]956<div class="doc_subsection">
957 <a name="namedmetadatastructure">Named Metadata</a>
958</div>
959
960<div class="doc_text">
961
Chris Lattnerc2f8f162010-01-15 21:50:19 +0000[diff] [blame]962<p>Named metadata is a collection of metadata. <a href="#metadata">Metadata
Dan Gohman093cb792010-07-21 18:54:18 +0000[diff] [blame]963 nodes</a> (but not metadata strings) are the only valid operands for
Chris Lattnerc2f8f162010-01-15 21:50:19 +0000[diff] [blame]964 a named metadata.</p>
Devang Pateld1a89692010-01-11 19:35:55 +0000[diff] [blame]965
966<h5>Syntax:</h5>
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]967<pre class="doc_code">
Dan Gohman093cb792010-07-21 18:54:18 +0000[diff] [blame]968; Some unnamed metadata nodes, which are referenced by the named metadata.
969!0 = metadata !{metadata !"zero"}
Devang Pateld1a89692010-01-11 19:35:55 +0000[diff] [blame]970!1 = metadata !{metadata !"one"}
Dan Gohman093cb792010-07-21 18:54:18 +0000[diff] [blame]971!2 = metadata !{metadata !"two"}
Dan Gohman58cd65f2010-07-13 19:48:13 +0000[diff] [blame]972; A named metadata.
Dan Gohman093cb792010-07-21 18:54:18 +0000[diff] [blame]973!name = !{!0, !1, !2}
Devang Pateld1a89692010-01-11 19:35:55 +0000[diff] [blame]974</pre>
Devang Pateld1a89692010-01-11 19:35:55 +0000[diff] [blame]975
976</div>
977
978<!-- ======================================================================= -->
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]979<div class="doc_subsection"><a name="paramattrs">Parameter Attributes</a></div>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]980
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]981<div class="doc_text">
982
983<p>The return type and each parameter of a function type may have a set of
984 <i>parameter attributes</i> associated with them. Parameter attributes are
985 used to communicate additional information about the result or parameters of
986 a function. Parameter attributes are considered to be part of the function,
987 not of the function type, so functions with different parameter attributes
988 can have the same function type.</p>
989
990<p>Parameter attributes are simple keywords that follow the type specified. If
991 multiple parameter attributes are needed, they are space separated. For
992 example:</p>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]993
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]994<pre class="doc_code">
Nick Lewyckydac78d82009-02-15 23:06:14 +0000[diff] [blame]995declare i32 @printf(i8* noalias nocapture, ...)
Chris Lattnerd2597d72008-10-04 18:33:34 +0000[diff] [blame]996declare i32 @atoi(i8 zeroext)
997declare signext i8 @returns_signed_char()
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]998</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]999
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1000<p>Note that any attributes for the function result (<tt>nounwind</tt>,
1001 <tt>readonly</tt>) come immediately after the argument list.</p>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1002
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1003<p>Currently, only the following parameter attributes are defined:</p>
Chris Lattner5cee13f2008-01-11 06:20:47 +0000[diff] [blame]1004
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1005<dl>
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1006 <dt><tt><b>zeroext</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1007 <dd>This indicates to the code generator that the parameter or return value
1008 should be zero-extended to a 32-bit value by the caller (for a parameter)
1009 or the callee (for a return value).</dd>
Chris Lattner5cee13f2008-01-11 06:20:47 +0000[diff] [blame]1010
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1011 <dt><tt><b>signext</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1012 <dd>This indicates to the code generator that the parameter or return value
1013 should be sign-extended to a 32-bit value by the caller (for a parameter)
1014 or the callee (for a return value).</dd>
Chris Lattner5cee13f2008-01-11 06:20:47 +0000[diff] [blame]1015
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1016 <dt><tt><b>inreg</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1017 <dd>This indicates that this parameter or return value should be treated in a
1018 special target-dependent fashion during while emitting code for a function
1019 call or return (usually, by putting it in a register as opposed to memory,
1020 though some targets use it to distinguish between two different kinds of
1021 registers). Use of this attribute is target-specific.</dd>
Chris Lattner5cee13f2008-01-11 06:20:47 +0000[diff] [blame]1022
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1023 <dt><tt><b><a name="byval">byval</a></b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1024 <dd>This indicates that the pointer parameter should really be passed by value
1025 to the function. The attribute implies that a hidden copy of the pointee
1026 is made between the caller and the callee, so the callee is unable to
1027 modify the value in the callee. This attribute is only valid on LLVM
1028 pointer arguments. It is generally used to pass structs and arrays by
1029 value, but is also valid on pointers to scalars. The copy is considered
1030 to belong to the caller not the callee (for example,
1031 <tt><a href="#readonly">readonly</a></tt> functions should not write to
1032 <tt>byval</tt> parameters). This is not a valid attribute for return
1033 values. The byval attribute also supports specifying an alignment with
1034 the align attribute. This has a target-specific effect on the code
1035 generator that usually indicates a desired alignment for the synthesized
1036 stack slot.</dd>
1037
Dan Gohman3770af52010-07-02 23:18:08 +0000[diff] [blame]1038 <dt><tt><b><a name="sret">sret</a></b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1039 <dd>This indicates that the pointer parameter specifies the address of a
1040 structure that is the return value of the function in the source program.
1041 This pointer must be guaranteed by the caller to be valid: loads and
1042 stores to the structure may be assumed by the callee to not to trap. This
1043 may only be applied to the first parameter. This is not a valid attribute
1044 for return values. </dd>
1045
Dan Gohman3770af52010-07-02 23:18:08 +0000[diff] [blame]1046 <dt><tt><b><a name="noalias">noalias</a></b></tt></dt>
Dan Gohmandf12d082010-07-02 18:41:32 +0000[diff] [blame]1047 <dd>This indicates that pointer values
1048 <a href="#pointeraliasing"><i>based</i></a> on the argument or return
Dan Gohmande256292010-07-02 23:46:54 +0000[diff] [blame]1049 value do not alias pointer values which are not <i>based</i> on it,
1050 ignoring certain "irrelevant" dependencies.
1051 For a call to the parent function, dependencies between memory
1052 references from before or after the call and from those during the call
1053 are "irrelevant" to the <tt>noalias</tt> keyword for the arguments and
1054 return value used in that call.
Dan Gohmandf12d082010-07-02 18:41:32 +0000[diff] [blame]1055 The caller shares the responsibility with the callee for ensuring that
1056 these requirements are met.
1057 For further details, please see the discussion of the NoAlias response in
Dan Gohman6c858db2010-07-06 15:26:33 +0000[diff] [blame]1058 <a href="AliasAnalysis.html#MustMayNo">alias analysis</a>.<br>
1059<br>
John McCall72ed8902010-07-06 21:07:14 +0000[diff] [blame]1060 Note that this definition of <tt>noalias</tt> is intentionally
1061 similar to the definition of <tt>restrict</tt> in C99 for function
Chris Lattner5eff9ca2010-07-06 20:51:35 +0000[diff] [blame]1062 arguments, though it is slightly weaker.
Dan Gohman6c858db2010-07-06 15:26:33 +0000[diff] [blame]1063<br>
1064 For function return values, C99's <tt>restrict</tt> is not meaningful,
1065 while LLVM's <tt>noalias</tt> is.
1066 </dd>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1067
Dan Gohman3770af52010-07-02 23:18:08 +0000[diff] [blame]1068 <dt><tt><b><a name="nocapture">nocapture</a></b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1069 <dd>This indicates that the callee does not make any copies of the pointer
1070 that outlive the callee itself. This is not a valid attribute for return
1071 values.</dd>
1072
Dan Gohman3770af52010-07-02 23:18:08 +0000[diff] [blame]1073 <dt><tt><b><a name="nest">nest</a></b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1074 <dd>This indicates that the pointer parameter can be excised using the
1075 <a href="#int_trampoline">trampoline intrinsics</a>. This is not a valid
1076 attribute for return values.</dd>
1077</dl>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1078
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1079</div>
1080
1081<!-- ======================================================================= -->
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]1082<div class="doc_subsection">
Gordon Henriksen71183b62007-12-10 03:18:06 +0000[diff] [blame]1083 <a name="gc">Garbage Collector Names</a>
1084</div>
1085
1086<div class="doc_text">
Gordon Henriksen71183b62007-12-10 03:18:06 +0000[diff] [blame]1087
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1088<p>Each function may specify a garbage collector name, which is simply a
1089 string:</p>
1090
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]1091<pre class="doc_code">
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1092define void @f() gc "name" { ... }
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1093</pre>
Gordon Henriksen71183b62007-12-10 03:18:06 +0000[diff] [blame]1094
1095<p>The compiler declares the supported values of <i>name</i>. Specifying a
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1096 collector which will cause the compiler to alter its output in order to
1097 support the named garbage collection algorithm.</p>
1098
Gordon Henriksen71183b62007-12-10 03:18:06 +0000[diff] [blame]1099</div>
1100
1101<!-- ======================================================================= -->
1102<div class="doc_subsection">
Devang Patel9eb525d2008-09-26 23:51:19 +0000[diff] [blame]1103 <a name="fnattrs">Function Attributes</a>
Devang Patelcaacdba2008-09-04 23:05:13 +0000[diff] [blame]1104</div>
1105
1106<div class="doc_text">
Devang Patel9eb525d2008-09-26 23:51:19 +0000[diff] [blame]1107
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1108<p>Function attributes are set to communicate additional information about a
1109 function. Function attributes are considered to be part of the function, not
1110 of the function type, so functions with different parameter attributes can
1111 have the same function type.</p>
Devang Patel9eb525d2008-09-26 23:51:19 +0000[diff] [blame]1112
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1113<p>Function attributes are simple keywords that follow the type specified. If
1114 multiple attributes are needed, they are space separated. For example:</p>
Devang Patelcaacdba2008-09-04 23:05:13 +0000[diff] [blame]1115
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]1116<pre class="doc_code">
Devang Patel9eb525d2008-09-26 23:51:19 +0000[diff] [blame]1117define void @f() noinline { ... }
1118define void @f() alwaysinline { ... }
1119define void @f() alwaysinline optsize { ... }
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1120define void @f() optsize { ... }
Bill Wendlingb175fa42008-09-07 10:26:33 +0000[diff] [blame]1121</pre>
Devang Patelcaacdba2008-09-04 23:05:13 +0000[diff] [blame]1122
Bill Wendlingb175fa42008-09-07 10:26:33 +0000[diff] [blame]1123<dl>
Charles Davisbe5557e2010-02-12 00:31:15 +0000[diff] [blame]1124 <dt><tt><b>alignstack(&lt;<em>n</em>&gt;)</b></tt></dt>
1125 <dd>This attribute indicates that, when emitting the prologue and epilogue,
1126 the backend should forcibly align the stack pointer. Specify the
1127 desired alignment, which must be a power of two, in parentheses.
1128
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1129 <dt><tt><b>alwaysinline</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1130 <dd>This attribute indicates that the inliner should attempt to inline this
1131 function into callers whenever possible, ignoring any active inlining size
1132 threshold for this caller.</dd>
Bill Wendlingb175fa42008-09-07 10:26:33 +0000[diff] [blame]1133
Jakob Stoklund Olesen74bb06c2010-02-06 01:16:28 +0000[diff] [blame]1134 <dt><tt><b>inlinehint</b></tt></dt>
1135 <dd>This attribute indicates that the source code contained a hint that inlining
1136 this function is desirable (such as the "inline" keyword in C/C++). It
1137 is just a hint; it imposes no requirements on the inliner.</dd>
1138
Nick Lewycky14b58da2010-07-06 18:24:09 +0000[diff] [blame]1139 <dt><tt><b>naked</b></tt></dt>
1140 <dd>This attribute disables prologue / epilogue emission for the function.
1141 This can have very system-specific consequences.</dd>
1142
1143 <dt><tt><b>noimplicitfloat</b></tt></dt>
1144 <dd>This attributes disables implicit floating point instructions.</dd>
1145
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1146 <dt><tt><b>noinline</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1147 <dd>This attribute indicates that the inliner should never inline this
1148 function in any situation. This attribute may not be used together with
1149 the <tt>alwaysinline</tt> attribute.</dd>
Devang Patel9eb525d2008-09-26 23:51:19 +0000[diff] [blame]1150
Nick Lewycky14b58da2010-07-06 18:24:09 +0000[diff] [blame]1151 <dt><tt><b>noredzone</b></tt></dt>
1152 <dd>This attribute indicates that the code generator should not use a red
1153 zone, even if the target-specific ABI normally permits it.</dd>
Devang Patel9eb525d2008-09-26 23:51:19 +0000[diff] [blame]1154
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1155 <dt><tt><b>noreturn</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1156 <dd>This function attribute indicates that the function never returns
1157 normally. This produces undefined behavior at runtime if the function
1158 ever does dynamically return.</dd>
Bill Wendlinga8130172008-11-13 01:02:51 +0000[diff] [blame]1159
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1160 <dt><tt><b>nounwind</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1161 <dd>This function attribute indicates that the function never returns with an
1162 unwind or exceptional control flow. If the function does unwind, its
1163 runtime behavior is undefined.</dd>
Bill Wendling0f5541e2008-11-26 19:07:40 +0000[diff] [blame]1164
Nick Lewycky14b58da2010-07-06 18:24:09 +0000[diff] [blame]1165 <dt><tt><b>optsize</b></tt></dt>
1166 <dd>This attribute suggests that optimization passes and code generator passes
1167 make choices that keep the code size of this function low, and otherwise
1168 do optimizations specifically to reduce code size.</dd>
1169
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1170 <dt><tt><b>readnone</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1171 <dd>This attribute indicates that the function computes its result (or decides
1172 to unwind an exception) based strictly on its arguments, without
1173 dereferencing any pointer arguments or otherwise accessing any mutable
1174 state (e.g. memory, control registers, etc) visible to caller functions.
1175 It does not write through any pointer arguments
1176 (including <tt><a href="#byval">byval</a></tt> arguments) and never
1177 changes any state visible to callers. This means that it cannot unwind
1178 exceptions by calling the <tt>C++</tt> exception throwing methods, but
1179 could use the <tt>unwind</tt> instruction.</dd>
Devang Patel310fd4a2009-06-12 19:45:19 +0000[diff] [blame]1180
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1181 <dt><tt><b><a name="readonly">readonly</a></b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1182 <dd>This attribute indicates that the function does not write through any
1183 pointer arguments (including <tt><a href="#byval">byval</a></tt>
1184 arguments) or otherwise modify any state (e.g. memory, control registers,
1185 etc) visible to caller functions. It may dereference pointer arguments
1186 and read state that may be set in the caller. A readonly function always
1187 returns the same value (or unwinds an exception identically) when called
1188 with the same set of arguments and global state. It cannot unwind an
1189 exception by calling the <tt>C++</tt> exception throwing methods, but may
1190 use the <tt>unwind</tt> instruction.</dd>
Anton Korobeynikovc8ce7b082009-07-17 18:07:26 +0000[diff] [blame]1191
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1192 <dt><tt><b><a name="ssp">ssp</a></b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1193 <dd>This attribute indicates that the function should emit a stack smashing
1194 protector. It is in the form of a "canary"&mdash;a random value placed on
1195 the stack before the local variables that's checked upon return from the
1196 function to see if it has been overwritten. A heuristic is used to
1197 determine if a function needs stack protectors or not.<br>
1198<br>
1199 If a function that has an <tt>ssp</tt> attribute is inlined into a
1200 function that doesn't have an <tt>ssp</tt> attribute, then the resulting
1201 function will have an <tt>ssp</tt> attribute.</dd>
1202
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1203 <dt><tt><b>sspreq</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1204 <dd>This attribute indicates that the function should <em>always</em> emit a
1205 stack smashing protector. This overrides
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1206 the <tt><a href="#ssp">ssp</a></tt> function attribute.<br>
1207<br>
1208 If a function that has an <tt>sspreq</tt> attribute is inlined into a
1209 function that doesn't have an <tt>sspreq</tt> attribute or which has
1210 an <tt>ssp</tt> attribute, then the resulting function will have
1211 an <tt>sspreq</tt> attribute.</dd>
Bill Wendlingb175fa42008-09-07 10:26:33 +0000[diff] [blame]1212</dl>
1213
Devang Patelcaacdba2008-09-04 23:05:13 +0000[diff] [blame]1214</div>
1215
1216<!-- ======================================================================= -->
1217<div class="doc_subsection">
Chris Lattner93564892006-04-08 04:40:53 +0000[diff] [blame]1218 <a name="moduleasm">Module-Level Inline Assembly</a>
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]1219</div>
1220
1221<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1222
1223<p>Modules may contain "module-level inline asm" blocks, which corresponds to
1224 the GCC "file scope inline asm" blocks. These blocks are internally
1225 concatenated by LLVM and treated as a single unit, but may be separated in
1226 the <tt>.ll</tt> file if desired. The syntax is very simple:</p>
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]1227
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]1228<pre class="doc_code">
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]1229module asm "inline asm code goes here"
1230module asm "more can go here"
1231</pre>
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]1232
1233<p>The strings can contain any character by escaping non-printable characters.
1234 The escape sequence used is simply "\xx" where "xx" is the two digit hex code
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1235 for the number.</p>
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]1236
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1237<p>The inline asm code is simply printed to the machine code .s file when
1238 assembly code is generated.</p>
1239
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]1240</div>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]1241
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1242<!-- ======================================================================= -->
1243<div class="doc_subsection">
1244 <a name="datalayout">Data Layout</a>
1245</div>
1246
1247<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1248
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1249<p>A module may specify a target specific data layout string that specifies how
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1250 data is to be laid out in memory. The syntax for the data layout is
1251 simply:</p>
1252
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]1253<pre class="doc_code">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1254target datalayout = "<i>layout specification</i>"
1255</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1256
1257<p>The <i>layout specification</i> consists of a list of specifications
1258 separated by the minus sign character ('-'). Each specification starts with
1259 a letter and may include other information after the letter to define some
1260 aspect of the data layout. The specifications accepted are as follows:</p>
1261
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1262<dl>
1263 <dt><tt>E</tt></dt>
1264 <dd>Specifies that the target lays out data in big-endian form. That is, the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1265 bits with the most significance have the lowest address location.</dd>
1266
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1267 <dt><tt>e</tt></dt>
Chris Lattner67c37d12008-08-05 18:29:16 +0000[diff] [blame]1268 <dd>Specifies that the target lays out data in little-endian form. That is,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1269 the bits with the least significance have the lowest address
1270 location.</dd>
1271
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1272 <dt><tt>p:<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]1273 <dd>This specifies the <i>size</i> of a pointer and its <i>abi</i> and
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1274 <i>preferred</i> alignments. All sizes are in bits. Specifying
1275 the <i>pref</i> alignment is optional. If omitted, the
1276 preceding <tt>:</tt> should be omitted too.</dd>
1277
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1278 <dt><tt>i<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1279 <dd>This specifies the alignment for an integer type of a given bit
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1280 <i>size</i>. The value of <i>size</i> must be in the range [1,2^23).</dd>
1281
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1282 <dt><tt>v<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]1283 <dd>This specifies the alignment for a vector type of a given bit
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1284 <i>size</i>.</dd>
1285
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1286 <dt><tt>f<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]1287 <dd>This specifies the alignment for a floating point type of a given bit
Dale Johannesence522852010-05-28 18:54:47 +0000[diff] [blame]1288 <i>size</i>. Only values of <i>size</i> that are supported by the target
1289 will work. 32 (float) and 64 (double) are supported on all targets;
1290 80 or 128 (different flavors of long double) are also supported on some
1291 targets.
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1292
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1293 <dt><tt>a<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1294 <dd>This specifies the alignment for an aggregate type of a given bit
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1295 <i>size</i>.</dd>
1296
Daniel Dunbar7921a592009-06-08 22:17:53 +0000[diff] [blame]1297 <dt><tt>s<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1298 <dd>This specifies the alignment for a stack object of a given bit
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1299 <i>size</i>.</dd>
Chris Lattnera381eff2009-11-07 09:35:34 +0000[diff] [blame]1300
1301 <dt><tt>n<i>size1</i>:<i>size2</i>:<i>size3</i>...</tt></dt>
1302 <dd>This specifies a set of native integer widths for the target CPU
1303 in bits. For example, it might contain "n32" for 32-bit PowerPC,
1304 "n32:64" for PowerPC 64, or "n8:16:32:64" for X86-64. Elements of
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]1305 this set are considered to support most general arithmetic
Chris Lattnera381eff2009-11-07 09:35:34 +0000[diff] [blame]1306 operations efficiently.</dd>
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1307</dl>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1308
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1309<p>When constructing the data layout for a given target, LLVM starts with a
Dan Gohman61110ae2010-04-28 00:36:01 +0000[diff] [blame]1310 default set of specifications which are then (possibly) overridden by the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1311 specifications in the <tt>datalayout</tt> keyword. The default specifications
1312 are given in this list:</p>
1313
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1314<ul>
1315 <li><tt>E</tt> - big endian</li>
Dan Gohman8ad777d2010-02-23 02:44:03 +0000[diff] [blame]1316 <li><tt>p:64:64:64</tt> - 64-bit pointers with 64-bit alignment</li>
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1317 <li><tt>i1:8:8</tt> - i1 is 8-bit (byte) aligned</li>
1318 <li><tt>i8:8:8</tt> - i8 is 8-bit (byte) aligned</li>
1319 <li><tt>i16:16:16</tt> - i16 is 16-bit aligned</li>
1320 <li><tt>i32:32:32</tt> - i32 is 32-bit aligned</li>
Chris Lattner67c37d12008-08-05 18:29:16 +0000[diff] [blame]1321 <li><tt>i64:32:64</tt> - i64 has ABI alignment of 32-bits but preferred
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1322 alignment of 64-bits</li>
1323 <li><tt>f32:32:32</tt> - float is 32-bit aligned</li>
1324 <li><tt>f64:64:64</tt> - double is 64-bit aligned</li>
1325 <li><tt>v64:64:64</tt> - 64-bit vector is 64-bit aligned</li>
1326 <li><tt>v128:128:128</tt> - 128-bit vector is 128-bit aligned</li>
1327 <li><tt>a0:0:1</tt> - aggregates are 8-bit aligned</li>
Daniel Dunbar7921a592009-06-08 22:17:53 +0000[diff] [blame]1328 <li><tt>s0:64:64</tt> - stack objects are 64-bit aligned</li>
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1329</ul>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1330
1331<p>When LLVM is determining the alignment for a given type, it uses the
1332 following rules:</p>
1333
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1334<ol>
1335 <li>If the type sought is an exact match for one of the specifications, that
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1336 specification is used.</li>
1337
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1338 <li>If no match is found, and the type sought is an integer type, then the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1339 smallest integer type that is larger than the bitwidth of the sought type
1340 is used. If none of the specifications are larger than the bitwidth then
1341 the the largest integer type is used. For example, given the default
1342 specifications above, the i7 type will use the alignment of i8 (next
1343 largest) while both i65 and i256 will use the alignment of i64 (largest
1344 specified).</li>
1345
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1346 <li>If no match is found, and the type sought is a vector type, then the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1347 largest vector type that is smaller than the sought vector type will be
1348 used as a fall back. This happens because &lt;128 x double&gt; can be
1349 implemented in terms of 64 &lt;2 x double&gt;, for example.</li>
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1350</ol>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1351
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1352</div>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]1353
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1354<!-- ======================================================================= -->
1355<div class="doc_subsection">
1356 <a name="pointeraliasing">Pointer Aliasing Rules</a>
1357</div>
1358
1359<div class="doc_text">
1360
Andreas Bolka8ae4e242009-07-29 00:02:05 +0000[diff] [blame]1361<p>Any memory access must be done through a pointer value associated
Andreas Bolkae39f0332009-07-27 20:37:10 +0000[diff] [blame]1362with an address range of the memory access, otherwise the behavior
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1363is undefined. Pointer values are associated with address ranges
1364according to the following rules:</p>
1365
1366<ul>
Dan Gohmandf12d082010-07-02 18:41:32 +0000[diff] [blame]1367 <li>A pointer value is associated with the addresses associated with
1368 any value it is <i>based</i> on.
Andreas Bolka8ae4e242009-07-29 00:02:05 +0000[diff] [blame]1369 <li>An address of a global variable is associated with the address
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1370 range of the variable's storage.</li>
1371 <li>The result value of an allocation instruction is associated with
1372 the address range of the allocated storage.</li>
1373 <li>A null pointer in the default address-space is associated with
Andreas Bolka8ae4e242009-07-29 00:02:05 +0000[diff] [blame]1374 no address.</li>
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1375 <li>An integer constant other than zero or a pointer value returned
1376 from a function not defined within LLVM may be associated with address
1377 ranges allocated through mechanisms other than those provided by
Andreas Bolka8ae4e242009-07-29 00:02:05 +0000[diff] [blame]1378 LLVM. Such ranges shall not overlap with any ranges of addresses
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1379 allocated by mechanisms provided by LLVM.</li>
Dan Gohmandf12d082010-07-02 18:41:32 +0000[diff] [blame]1380</ul>
1381
1382<p>A pointer value is <i>based</i> on another pointer value according
1383 to the following rules:</p>
1384
1385<ul>
1386 <li>A pointer value formed from a
1387 <tt><a href="#i_getelementptr">getelementptr</a></tt> operation
1388 is <i>based</i> on the first operand of the <tt>getelementptr</tt>.</li>
1389 <li>The result value of a
1390 <tt><a href="#i_bitcast">bitcast</a></tt> is <i>based</i> on the operand
1391 of the <tt>bitcast</tt>.</li>
1392 <li>A pointer value formed by an
1393 <tt><a href="#i_inttoptr">inttoptr</a></tt> is <i>based</i> on all
1394 pointer values that contribute (directly or indirectly) to the
1395 computation of the pointer's value.</li>
1396 <li>The "<i>based</i> on" relationship is transitive.</li>
1397</ul>
1398
1399<p>Note that this definition of <i>"based"</i> is intentionally
1400 similar to the definition of <i>"based"</i> in C99, though it is
1401 slightly weaker.</p>
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1402
1403<p>LLVM IR does not associate types with memory. The result type of a
Andreas Bolka8ae4e242009-07-29 00:02:05 +0000[diff] [blame]1404<tt><a href="#i_load">load</a></tt> merely indicates the size and
1405alignment of the memory from which to load, as well as the
Dan Gohman4eb47192010-06-17 19:23:50 +0000[diff] [blame]1406interpretation of the value. The first operand type of a
Andreas Bolka8ae4e242009-07-29 00:02:05 +0000[diff] [blame]1407<tt><a href="#i_store">store</a></tt> similarly only indicates the size
1408and alignment of the store.</p>
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1409
1410<p>Consequently, type-based alias analysis, aka TBAA, aka
1411<tt>-fstrict-aliasing</tt>, is not applicable to general unadorned
1412LLVM IR. <a href="#metadata">Metadata</a> may be used to encode
1413additional information which specialized optimization passes may use
1414to implement type-based alias analysis.</p>
1415
1416</div>
1417
Jeffrey Yasskin5d284ae2010-04-26 21:21:24 +0000[diff] [blame]1418<!-- ======================================================================= -->
1419<div class="doc_subsection">
1420 <a name="volatile">Volatile Memory Accesses</a>
1421</div>
1422
1423<div class="doc_text">
1424
1425<p>Certain memory accesses, such as <a href="#i_load"><tt>load</tt></a>s, <a
1426href="#i_store"><tt>store</tt></a>s, and <a
1427href="#int_memcpy"><tt>llvm.memcpy</tt></a>s may be marked <tt>volatile</tt>.
1428The optimizers must not change the number of volatile operations or change their
1429order of execution relative to other volatile operations. The optimizers
1430<i>may</i> change the order of volatile operations relative to non-volatile
1431operations. This is not Java's "volatile" and has no cross-thread
1432synchronization behavior.</p>
1433
1434</div>
1435
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1436<!-- *********************************************************************** -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1437<div class="doc_section"> <a name="typesystem">Type System</a> </div>
1438<!-- *********************************************************************** -->
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]1439
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1440<div class="doc_text">
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]1441
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1442<p>The LLVM type system is one of the most important features of the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1443 intermediate representation. Being typed enables a number of optimizations
1444 to be performed on the intermediate representation directly, without having
1445 to do extra analyses on the side before the transformation. A strong type
1446 system makes it easier to read the generated code and enables novel analyses
1447 and transformations that are not feasible to perform on normal three address
1448 code representations.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]1449
1450</div>
1451
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1452<!-- ======================================================================= -->
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1453<div class="doc_subsection"> <a name="t_classifications">Type
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1454Classifications</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1455
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1456<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1457
1458<p>The types fall into a few useful classifications:</p>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]1459
1460<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1461 <tbody>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1462 <tr><th>Classification</th><th>Types</th></tr>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1463 <tr>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1464 <td><a href="#t_integer">integer</a></td>
Reid Spencer138249b2007-05-16 18:44:01 +0000[diff] [blame]1465 <td><tt>i1, i2, i3, ... i8, ... i16, ... i32, ... i64, ... </tt></td>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1466 </tr>
1467 <tr>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1468 <td><a href="#t_floating">floating point</a></td>
1469 <td><tt>float, double, x86_fp80, fp128, ppc_fp128</tt></td>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1470 </tr>
1471 <tr>
1472 <td><a name="t_firstclass">first class</a></td>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1473 <td><a href="#t_integer">integer</a>,
1474 <a href="#t_floating">floating point</a>,
1475 <a href="#t_pointer">pointer</a>,
Dan Gohman08783a882008-06-18 18:42:13 +0000[diff] [blame]1476 <a href="#t_vector">vector</a>,
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]1477 <a href="#t_struct">structure</a>,
1478 <a href="#t_array">array</a>,
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1479 <a href="#t_label">label</a>,
1480 <a href="#t_metadata">metadata</a>.
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1481 </td>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1482 </tr>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1483 <tr>
1484 <td><a href="#t_primitive">primitive</a></td>
1485 <td><a href="#t_label">label</a>,
1486 <a href="#t_void">void</a>,
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1487 <a href="#t_floating">floating point</a>,
Dale Johannesen33e5c352010-10-01 00:48:59 +0000[diff] [blame]1488 <a href="#t_x86mmx">x86mmx</a>,
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1489 <a href="#t_metadata">metadata</a>.</td>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1490 </tr>
1491 <tr>
1492 <td><a href="#t_derived">derived</a></td>
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]1493 <td><a href="#t_array">array</a>,
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1494 <a href="#t_function">function</a>,
1495 <a href="#t_pointer">pointer</a>,
1496 <a href="#t_struct">structure</a>,
1497 <a href="#t_pstruct">packed structure</a>,
1498 <a href="#t_vector">vector</a>,
1499 <a href="#t_opaque">opaque</a>.
Dan Gohman93bf60d2008-10-14 16:32:04 +0000[diff] [blame]1500 </td>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1501 </tr>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1502 </tbody>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1503</table>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]1504
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1505<p>The <a href="#t_firstclass">first class</a> types are perhaps the most
1506 important. Values of these types are the only ones which can be produced by
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]1507 instructions.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1508
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1509</div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1510
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1511<!-- ======================================================================= -->
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1512<div class="doc_subsection"> <a name="t_primitive">Primitive Types</a> </div>
Chris Lattner43542b32008-01-04 04:34:14 +0000[diff] [blame]1513
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1514<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1515
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1516<p>The primitive types are the fundamental building blocks of the LLVM
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1517 system.</p>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1518
Chris Lattner43542b32008-01-04 04:34:14 +0000[diff] [blame]1519</div>
1520
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1521<!-- _______________________________________________________________________ -->
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]1522<div class="doc_subsubsection"> <a name="t_integer">Integer Type</a> </div>
1523
1524<div class="doc_text">
1525
1526<h5>Overview:</h5>
1527<p>The integer type is a very simple type that simply specifies an arbitrary
1528 bit width for the integer type desired. Any bit width from 1 bit to
1529 2<sup>23</sup>-1 (about 8 million) can be specified.</p>
1530
1531<h5>Syntax:</h5>
1532<pre>
1533 iN
1534</pre>
1535
1536<p>The number of bits the integer will occupy is specified by the <tt>N</tt>
1537 value.</p>
1538
1539<h5>Examples:</h5>
1540<table class="layout">
1541 <tr class="layout">
1542 <td class="left"><tt>i1</tt></td>
1543 <td class="left">a single-bit integer.</td>
1544 </tr>
1545 <tr class="layout">
1546 <td class="left"><tt>i32</tt></td>
1547 <td class="left">a 32-bit integer.</td>
1548 </tr>
1549 <tr class="layout">
1550 <td class="left"><tt>i1942652</tt></td>
1551 <td class="left">a really big integer of over 1 million bits.</td>
1552 </tr>
1553</table>
1554
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]1555</div>
1556
1557<!-- _______________________________________________________________________ -->
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1558<div class="doc_subsubsection"> <a name="t_floating">Floating Point Types</a> </div>
1559
1560<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1561
1562<table>
1563 <tbody>
1564 <tr><th>Type</th><th>Description</th></tr>
1565 <tr><td><tt>float</tt></td><td>32-bit floating point value</td></tr>
1566 <tr><td><tt>double</tt></td><td>64-bit floating point value</td></tr>
1567 <tr><td><tt>fp128</tt></td><td>128-bit floating point value (112-bit mantissa)</td></tr>
1568 <tr><td><tt>x86_fp80</tt></td><td>80-bit floating point value (X87)</td></tr>
1569 <tr><td><tt>ppc_fp128</tt></td><td>128-bit floating point value (two 64-bits)</td></tr>
1570 </tbody>
1571</table>
1572
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1573</div>
1574
1575<!-- _______________________________________________________________________ -->
Dale Johannesen33e5c352010-10-01 00:48:59 +0000[diff] [blame]1576<div class="doc_subsubsection"> <a name="t_x86mmx">X86mmx Type</a> </div>
1577
1578<div class="doc_text">
1579
1580<h5>Overview:</h5>
1581<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>
1582
1583<h5>Syntax:</h5>
1584<pre>
Dale Johannesenb1f0ff12010-10-01 01:07:02 +0000[diff] [blame^]1585 x86mmx
Dale Johannesen33e5c352010-10-01 00:48:59 +0000[diff] [blame]1586</pre>
1587
1588</div>
1589
1590<!-- _______________________________________________________________________ -->
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1591<div class="doc_subsubsection"> <a name="t_void">Void Type</a> </div>
1592
1593<div class="doc_text">
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1594
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1595<h5>Overview:</h5>
1596<p>The void type does not represent any value and has no size.</p>
1597
1598<h5>Syntax:</h5>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1599<pre>
1600 void
1601</pre>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1602
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1603</div>
1604
1605<!-- _______________________________________________________________________ -->
1606<div class="doc_subsubsection"> <a name="t_label">Label Type</a> </div>
1607
1608<div class="doc_text">
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1609
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1610<h5>Overview:</h5>
1611<p>The label type represents code labels.</p>
1612
1613<h5>Syntax:</h5>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1614<pre>
1615 label
1616</pre>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1617
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1618</div>
1619
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1620<!-- _______________________________________________________________________ -->
1621<div class="doc_subsubsection"> <a name="t_metadata">Metadata Type</a> </div>
1622
1623<div class="doc_text">
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1624
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1625<h5>Overview:</h5>
Nick Lewycky93e06a52009-09-27 23:27:42 +0000[diff] [blame]1626<p>The metadata type represents embedded metadata. No derived types may be
1627 created from metadata except for <a href="#t_function">function</a>
1628 arguments.
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1629
1630<h5>Syntax:</h5>
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1631<pre>
1632 metadata
1633</pre>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1634
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1635</div>
1636
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1637
1638<!-- ======================================================================= -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1639<div class="doc_subsection"> <a name="t_derived">Derived Types</a> </div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1640
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1641<div class="doc_text">
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1642
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1643<p>The real power in LLVM comes from the derived types in the system. This is
1644 what allows a programmer to represent arrays, functions, pointers, and other
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]1645 useful types. Each of these types contain one or more element types which
1646 may be a primitive type, or another derived type. For example, it is
1647 possible to have a two dimensional array, using an array as the element type
1648 of another array.</p>
Dan Gohman142ccc02009-01-24 15:58:40 +0000[diff] [blame]1649
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]1650
1651</div>
1652
1653<!-- _______________________________________________________________________ -->
1654<div class="doc_subsubsection"> <a name="t_aggregate">Aggregate Types</a> </div>
1655
1656<div class="doc_text">
1657
1658<p>Aggregate Types are a subset of derived types that can contain multiple
1659 member types. <a href="#t_array">Arrays</a>,
Chris Lattner13ee7952010-08-28 04:09:24 +0000[diff] [blame]1660 <a href="#t_struct">structs</a>, and <a href="#t_vector">vectors</a> are
1661 aggregate types.</p>
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]1662
1663</div>
1664
Reid Spencer138249b2007-05-16 18:44:01 +0000[diff] [blame]1665<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1666<div class="doc_subsubsection"> <a name="t_array">Array Type</a> </div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1667
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1668<div class="doc_text">
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1669
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1670<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1671<p>The array type is a very simple derived type that arranges elements
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1672 sequentially in memory. The array type requires a size (number of elements)
1673 and an underlying data type.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1674
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]1675<h5>Syntax:</h5>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1676<pre>
1677 [&lt;# elements&gt; x &lt;elementtype&gt;]
1678</pre>
1679
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1680<p>The number of elements is a constant integer value; <tt>elementtype</tt> may
1681 be any type with a size.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1682
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]1683<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1684<table class="layout">
1685 <tr class="layout">
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]1686 <td class="left"><tt>[40 x i32]</tt></td>
1687 <td class="left">Array of 40 32-bit integer values.</td>
1688 </tr>
1689 <tr class="layout">
1690 <td class="left"><tt>[41 x i32]</tt></td>
1691 <td class="left">Array of 41 32-bit integer values.</td>
1692 </tr>
1693 <tr class="layout">
1694 <td class="left"><tt>[4 x i8]</tt></td>
1695 <td class="left">Array of 4 8-bit integer values.</td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1696 </tr>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1697</table>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1698<p>Here are some examples of multidimensional arrays:</p>
1699<table class="layout">
1700 <tr class="layout">
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]1701 <td class="left"><tt>[3 x [4 x i32]]</tt></td>
1702 <td class="left">3x4 array of 32-bit integer values.</td>
1703 </tr>
1704 <tr class="layout">
1705 <td class="left"><tt>[12 x [10 x float]]</tt></td>
1706 <td class="left">12x10 array of single precision floating point values.</td>
1707 </tr>
1708 <tr class="layout">
1709 <td class="left"><tt>[2 x [3 x [4 x i16]]]</tt></td>
1710 <td class="left">2x3x4 array of 16-bit integer values.</td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1711 </tr>
1712</table>
Chris Lattnerc0ad71e2005-06-24 17:22:57 +0000[diff] [blame]1713
Dan Gohmanc74bc282009-11-09 19:01:53 +0000[diff] [blame]1714<p>There is no restriction on indexing beyond the end of the array implied by
1715 a static type (though there are restrictions on indexing beyond the bounds
1716 of an allocated object in some cases). This means that single-dimension
1717 'variable sized array' addressing can be implemented in LLVM with a zero
1718 length array type. An implementation of 'pascal style arrays' in LLVM could
1719 use the type "<tt>{ i32, [0 x float]}</tt>", for example.</p>
Chris Lattnerc0ad71e2005-06-24 17:22:57 +0000[diff] [blame]1720
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1721</div>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1722
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1723<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1724<div class="doc_subsubsection"> <a name="t_function">Function Type</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1725
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1726<div class="doc_text">
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]1727
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1728<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1729<p>The function type can be thought of as a function signature. It consists of
1730 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]1731 function type is a first class type or a void type.</p>
Devang Pateld6cff512008-03-10 20:49:15 +0000[diff] [blame]1732
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1733<h5>Syntax:</h5>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]1734<pre>
Nick Lewycky14d1ccc2009-09-27 07:55:32 +0000[diff] [blame]1735 &lt;returntype&gt; (&lt;parameter list&gt;)
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]1736</pre>
1737
John Criswell4c0cf7f2005-10-24 16:17:18 +0000[diff] [blame]1738<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]1739 specifiers. Optionally, the parameter list may include a type <tt>...</tt>,
1740 which indicates that the function takes a variable number of arguments.
1741 Variable argument functions can access their arguments with
1742 the <a href="#int_varargs">variable argument handling intrinsic</a>
Chris Lattner47f2a832010-03-02 06:36:51 +0000[diff] [blame]1743 functions. '<tt>&lt;returntype&gt;</tt>' is any type except
Nick Lewycky93e06a52009-09-27 23:27:42 +0000[diff] [blame]1744 <a href="#t_label">label</a>.</p>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]1745
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1746<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1747<table class="layout">
1748 <tr class="layout">
Reid Spencer58c08712006-12-31 07:18:34 +0000[diff] [blame]1749 <td class="left"><tt>i32 (i32)</tt></td>
1750 <td class="left">function taking an <tt>i32</tt>, returning an <tt>i32</tt>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1751 </td>
Reid Spencer58c08712006-12-31 07:18:34 +0000[diff] [blame]1752 </tr><tr class="layout">
Chris Lattner47f2a832010-03-02 06:36:51 +0000[diff] [blame]1753 <td class="left"><tt>float&nbsp;(i16,&nbsp;i32&nbsp;*)&nbsp;*
Reid Spencer655dcc62006-12-31 07:20:23 +0000[diff] [blame]1754 </tt></td>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]1755 <td class="left"><a href="#t_pointer">Pointer</a> to a function that takes
Chris Lattner47f2a832010-03-02 06:36:51 +0000[diff] [blame]1756 an <tt>i16</tt> and a <a href="#t_pointer">pointer</a> to <tt>i32</tt>,
1757 returning <tt>float</tt>.
Reid Spencer58c08712006-12-31 07:18:34 +0000[diff] [blame]1758 </td>
1759 </tr><tr class="layout">
1760 <td class="left"><tt>i32 (i8*, ...)</tt></td>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]1761 <td class="left">A vararg function that takes at least one
1762 <a href="#t_pointer">pointer</a> to <tt>i8 </tt> (char in C),
1763 which returns an integer. This is the signature for <tt>printf</tt> in
Reid Spencer58c08712006-12-31 07:18:34 +0000[diff] [blame]1764 LLVM.
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1765 </td>
Devang Patele3dfc1c2008-03-24 05:35:41 +0000[diff] [blame]1766 </tr><tr class="layout">
1767 <td class="left"><tt>{i32, i32} (i32)</tt></td>
Nick Lewycky14d1ccc2009-09-27 07:55:32 +0000[diff] [blame]1768 <td class="left">A function taking an <tt>i32</tt>, returning a
1769 <a href="#t_struct">structure</a> containing two <tt>i32</tt> values
Devang Patele3dfc1c2008-03-24 05:35:41 +0000[diff] [blame]1770 </td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1771 </tr>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1772</table>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]1773
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1774</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1775
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1776<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1777<div class="doc_subsubsection"> <a name="t_struct">Structure Type</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1778
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1779<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1780
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1781<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1782<p>The structure type is used to represent a collection of data members together
1783 in memory. The packing of the field types is defined to match the ABI of the
1784 underlying processor. The elements of a structure may be any type that has a
1785 size.</p>
1786
Jeffrey Yasskinf991bbb2010-01-11 19:19:26 +0000[diff] [blame]1787<p>Structures in memory are accessed using '<tt><a href="#i_load">load</a></tt>'
1788 and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a field
1789 with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.
1790 Structures in registers are accessed using the
1791 '<tt><a href="#i_extractvalue">extractvalue</a></tt>' and
1792 '<tt><a href="#i_insertvalue">insertvalue</a></tt>' instructions.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1793<h5>Syntax:</h5>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1794<pre>
1795 { &lt;type list&gt; }
1796</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1797
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1798<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1799<table class="layout">
1800 <tr class="layout">
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]1801 <td class="left"><tt>{ i32, i32, i32 }</tt></td>
1802 <td class="left">A triple of three <tt>i32</tt> values</td>
1803 </tr><tr class="layout">
1804 <td class="left"><tt>{&nbsp;float,&nbsp;i32&nbsp;(i32)&nbsp;*&nbsp;}</tt></td>
1805 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1806 second element is a <a href="#t_pointer">pointer</a> to a
1807 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1808 an <tt>i32</tt>.</td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1809 </tr>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1810</table>
Dan Gohman142ccc02009-01-24 15:58:40 +0000[diff] [blame]1811
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1812</div>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1813
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1814<!-- _______________________________________________________________________ -->
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]1815<div class="doc_subsubsection"> <a name="t_pstruct">Packed Structure Type</a>
1816</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1817
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]1818<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1819
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]1820<h5>Overview:</h5>
1821<p>The packed structure type is used to represent a collection of data members
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1822 together in memory. There is no padding between fields. Further, the
1823 alignment of a packed structure is 1 byte. The elements of a packed
1824 structure may be any type that has a size.</p>
1825
1826<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt> and
1827 '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a field with
1828 the '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
1829
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]1830<h5>Syntax:</h5>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1831<pre>
1832 &lt; { &lt;type list&gt; } &gt;
1833</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1834
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]1835<h5>Examples:</h5>
1836<table class="layout">
1837 <tr class="layout">
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]1838 <td class="left"><tt>&lt; { i32, i32, i32 } &gt;</tt></td>
1839 <td class="left">A triple of three <tt>i32</tt> values</td>
1840 </tr><tr class="layout">
Bill Wendlingb175fa42008-09-07 10:26:33 +0000[diff] [blame]1841 <td class="left">
1842<tt>&lt;&nbsp;{&nbsp;float,&nbsp;i32&nbsp;(i32)*&nbsp;}&nbsp;&gt;</tt></td>
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]1843 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1844 second element is a <a href="#t_pointer">pointer</a> to a
1845 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1846 an <tt>i32</tt>.</td>
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]1847 </tr>
1848</table>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1849
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]1850</div>
1851
1852<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1853<div class="doc_subsubsection"> <a name="t_pointer">Pointer Type</a> </div>
Chris Lattner4a67c912009-02-08 19:53:29 +0000[diff] [blame]1854
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1855<div class="doc_text">
1856
1857<h5>Overview:</h5>
Dan Gohman88481112010-02-25 16:50:07 +0000[diff] [blame]1858<p>The pointer type is used to specify memory locations.
1859 Pointers are commonly used to reference objects in memory.</p>
1860
1861<p>Pointer types may have an optional address space attribute defining the
1862 numbered address space where the pointed-to object resides. The default
1863 address space is number zero. The semantics of non-zero address
1864 spaces are target-specific.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1865
1866<p>Note that LLVM does not permit pointers to void (<tt>void*</tt>) nor does it
1867 permit pointers to labels (<tt>label*</tt>). Use <tt>i8*</tt> instead.</p>
Chris Lattner4a67c912009-02-08 19:53:29 +0000[diff] [blame]1868
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]1869<h5>Syntax:</h5>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1870<pre>
1871 &lt;type&gt; *
1872</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1873
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]1874<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1875<table class="layout">
1876 <tr class="layout">
Dan Gohman623806e2009-01-04 23:44:43 +0000[diff] [blame]1877 <td class="left"><tt>[4 x i32]*</tt></td>
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]1878 <td class="left">A <a href="#t_pointer">pointer</a> to <a
1879 href="#t_array">array</a> of four <tt>i32</tt> values.</td>
1880 </tr>
1881 <tr class="layout">
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]1882 <td class="left"><tt>i32 (i32*) *</tt></td>
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]1883 <td class="left"> A <a href="#t_pointer">pointer</a> to a <a
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1884 href="#t_function">function</a> that takes an <tt>i32*</tt>, returning an
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]1885 <tt>i32</tt>.</td>
1886 </tr>
1887 <tr class="layout">
1888 <td class="left"><tt>i32 addrspace(5)*</tt></td>
1889 <td class="left">A <a href="#t_pointer">pointer</a> to an <tt>i32</tt> value
1890 that resides in address space #5.</td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1891 </tr>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1892</table>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1893
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1894</div>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1895
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1896<!-- _______________________________________________________________________ -->
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]1897<div class="doc_subsubsection"> <a name="t_vector">Vector Type</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1898
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1899<div class="doc_text">
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1900
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1901<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1902<p>A vector type is a simple derived type that represents a vector of elements.
1903 Vector types are used when multiple primitive data are operated in parallel
1904 using a single instruction (SIMD). A vector type requires a size (number of
Duncan Sands31c0e0e2009-11-27 13:38:03 +0000[diff] [blame]1905 elements) and an underlying primitive data type. Vector types are considered
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1906 <a href="#t_firstclass">first class</a>.</p>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1907
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1908<h5>Syntax:</h5>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1909<pre>
1910 &lt; &lt;# elements&gt; x &lt;elementtype&gt; &gt;
1911</pre>
1912
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1913<p>The number of elements is a constant integer value; elementtype may be any
1914 integer or floating point type.</p>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1915
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1916<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1917<table class="layout">
1918 <tr class="layout">
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]1919 <td class="left"><tt>&lt;4 x i32&gt;</tt></td>
1920 <td class="left">Vector of 4 32-bit integer values.</td>
1921 </tr>
1922 <tr class="layout">
1923 <td class="left"><tt>&lt;8 x float&gt;</tt></td>
1924 <td class="left">Vector of 8 32-bit floating-point values.</td>
1925 </tr>
1926 <tr class="layout">
1927 <td class="left"><tt>&lt;2 x i64&gt;</tt></td>
1928 <td class="left">Vector of 2 64-bit integer values.</td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1929 </tr>
1930</table>
Dan Gohman142ccc02009-01-24 15:58:40 +0000[diff] [blame]1931
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1932</div>
1933
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1934<!-- _______________________________________________________________________ -->
1935<div class="doc_subsubsection"> <a name="t_opaque">Opaque Type</a> </div>
1936<div class="doc_text">
1937
1938<h5>Overview:</h5>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1939<p>Opaque types are used to represent unknown types in the system. This
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1940 corresponds (for example) to the C notion of a forward declared structure
1941 type. In LLVM, opaque types can eventually be resolved to any type (not just
1942 a structure type).</p>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1943
1944<h5>Syntax:</h5>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1945<pre>
1946 opaque
1947</pre>
1948
1949<h5>Examples:</h5>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1950<table class="layout">
1951 <tr class="layout">
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]1952 <td class="left"><tt>opaque</tt></td>
1953 <td class="left">An opaque type.</td>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1954 </tr>
1955</table>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1956
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1957</div>
1958
Chris Lattnercf7a5842009-02-02 07:32:36 +0000[diff] [blame]1959<!-- ======================================================================= -->
1960<div class="doc_subsection">
1961 <a name="t_uprefs">Type Up-references</a>
1962</div>
1963
1964<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1965
Chris Lattnercf7a5842009-02-02 07:32:36 +0000[diff] [blame]1966<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1967<p>An "up reference" allows you to refer to a lexically enclosing type without
1968 requiring it to have a name. For instance, a structure declaration may
1969 contain a pointer to any of the types it is lexically a member of. Example
1970 of up references (with their equivalent as named type declarations)
1971 include:</p>
Chris Lattnercf7a5842009-02-02 07:32:36 +0000[diff] [blame]1972
1973<pre>
Chris Lattnerbf1d5452009-02-09 10:00:56 +0000[diff] [blame]1974 { \2 * } %x = type { %x* }
Chris Lattnercf7a5842009-02-02 07:32:36 +0000[diff] [blame]1975 { \2 }* %y = type { %y }*
1976 \1* %z = type %z*
1977</pre>
1978
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1979<p>An up reference is needed by the asmprinter for printing out cyclic types
1980 when there is no declared name for a type in the cycle. Because the
1981 asmprinter does not want to print out an infinite type string, it needs a
1982 syntax to handle recursive types that have no names (all names are optional
1983 in llvm IR).</p>
Chris Lattnercf7a5842009-02-02 07:32:36 +0000[diff] [blame]1984
1985<h5>Syntax:</h5>
1986<pre>
1987 \&lt;level&gt;
1988</pre>
1989
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1990<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]1991
1992<h5>Examples:</h5>
Chris Lattnercf7a5842009-02-02 07:32:36 +0000[diff] [blame]1993<table class="layout">
1994 <tr class="layout">
1995 <td class="left"><tt>\1*</tt></td>
1996 <td class="left">Self-referential pointer.</td>
1997 </tr>
1998 <tr class="layout">
1999 <td class="left"><tt>{ { \3*, i8 }, i32 }</tt></td>
2000 <td class="left">Recursive structure where the upref refers to the out-most
2001 structure.</td>
2002 </tr>
2003</table>
Chris Lattnercf7a5842009-02-02 07:32:36 +0000[diff] [blame]2004
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2005</div>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]2006
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2007<!-- *********************************************************************** -->
2008<div class="doc_section"> <a name="constants">Constants</a> </div>
2009<!-- *********************************************************************** -->
2010
2011<div class="doc_text">
2012
2013<p>LLVM has several different basic types of constants. This section describes
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2014 them all and their syntax.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2015
2016</div>
2017
2018<!-- ======================================================================= -->
Reid Spencer8f08d802004-12-09 18:02:53 +0000[diff] [blame]2019<div class="doc_subsection"><a name="simpleconstants">Simple Constants</a></div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2020
2021<div class="doc_text">
2022
2023<dl>
2024 <dt><b>Boolean constants</b></dt>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2025 <dd>The two strings '<tt>true</tt>' and '<tt>false</tt>' are both valid
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]2026 constants of the <tt><a href="#t_integer">i1</a></tt> type.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2027
2028 <dt><b>Integer constants</b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2029 <dd>Standard integers (such as '4') are constants of
2030 the <a href="#t_integer">integer</a> type. Negative numbers may be used
2031 with integer types.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2032
2033 <dt><b>Floating point constants</b></dt>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2034 <dd>Floating point constants use standard decimal notation (e.g. 123.421),
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2035 exponential notation (e.g. 1.23421e+2), or a more precise hexadecimal
2036 notation (see below). The assembler requires the exact decimal value of a
2037 floating-point constant. For example, the assembler accepts 1.25 but
2038 rejects 1.3 because 1.3 is a repeating decimal in binary. Floating point
2039 constants must have a <a href="#t_floating">floating point</a> type. </dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2040
2041 <dt><b>Null pointer constants</b></dt>
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]2042 <dd>The identifier '<tt>null</tt>' is recognized as a null pointer constant
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2043 and must be of <a href="#t_pointer">pointer type</a>.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2044</dl>
2045
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2046<p>The one non-intuitive notation for constants is the hexadecimal form of
2047 floating point constants. For example, the form '<tt>double
2048 0x432ff973cafa8000</tt>' is equivalent to (but harder to read than)
2049 '<tt>double 4.5e+15</tt>'. The only time hexadecimal floating point
2050 constants are required (and the only time that they are generated by the
2051 disassembler) is when a floating point constant must be emitted but it cannot
2052 be represented as a decimal floating point number in a reasonable number of
2053 digits. For example, NaN's, infinities, and other special values are
2054 represented in their IEEE hexadecimal format so that assembly and disassembly
2055 do not cause any bits to change in the constants.</p>
2056
Dale Johannesencd4a3012009-02-11 22:14:51 +0000[diff] [blame]2057<p>When using the hexadecimal form, constants of types float and double are
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2058 represented using the 16-digit form shown above (which matches the IEEE754
2059 representation for double); float values must, however, be exactly
2060 representable as IEE754 single precision. Hexadecimal format is always used
2061 for long double, and there are three forms of long double. The 80-bit format
2062 used by x86 is represented as <tt>0xK</tt> followed by 20 hexadecimal digits.
2063 The 128-bit format used by PowerPC (two adjacent doubles) is represented
2064 by <tt>0xM</tt> followed by 32 hexadecimal digits. The IEEE 128-bit format
2065 is represented by <tt>0xL</tt> followed by 32 hexadecimal digits; no
2066 currently supported target uses this format. Long doubles will only work if
2067 they match the long double format on your target. All hexadecimal formats
2068 are big-endian (sign bit at the left).</p>
2069
Dale Johannesen33e5c352010-10-01 00:48:59 +0000[diff] [blame]2070<p>There are no constants of type x86mmx.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2071</div>
2072
2073<!-- ======================================================================= -->
Chris Lattner361bfcd2009-02-28 18:32:25 +0000[diff] [blame]2074<div class="doc_subsection">
Bill Wendling972b7202009-07-20 02:32:41 +0000[diff] [blame]2075<a name="aggregateconstants"></a> <!-- old anchor -->
2076<a name="complexconstants">Complex Constants</a>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2077</div>
2078
2079<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2080
Chris Lattner361bfcd2009-02-28 18:32:25 +0000[diff] [blame]2081<p>Complex constants are a (potentially recursive) combination of simple
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2082 constants and smaller complex constants.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2083
2084<dl>
2085 <dt><b>Structure constants</b></dt>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2086 <dd>Structure constants are represented with notation similar to structure
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2087 type definitions (a comma separated list of elements, surrounded by braces
2088 (<tt>{}</tt>)). For example: "<tt>{ i32 4, float 17.0, i32* @G }</tt>",
2089 where "<tt>@G</tt>" is declared as "<tt>@G = external global i32</tt>".
2090 Structure constants must have <a href="#t_struct">structure type</a>, and
2091 the number and types of elements must match those specified by the
2092 type.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2093
2094 <dt><b>Array constants</b></dt>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2095 <dd>Array constants are represented with notation similar to array type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2096 definitions (a comma separated list of elements, surrounded by square
2097 brackets (<tt>[]</tt>)). For example: "<tt>[ i32 42, i32 11, i32 74
2098 ]</tt>". Array constants must have <a href="#t_array">array type</a>, and
2099 the number and types of elements must match those specified by the
2100 type.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2101
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]2102 <dt><b>Vector constants</b></dt>
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]2103 <dd>Vector constants are represented with notation similar to vector type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2104 definitions (a comma separated list of elements, surrounded by
2105 less-than/greater-than's (<tt>&lt;&gt;</tt>)). For example: "<tt>&lt; i32
2106 42, i32 11, i32 74, i32 100 &gt;</tt>". Vector constants must
2107 have <a href="#t_vector">vector type</a>, and the number and types of
2108 elements must match those specified by the type.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2109
2110 <dt><b>Zero initialization</b></dt>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2111 <dd>The string '<tt>zeroinitializer</tt>' can be used to zero initialize a
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]2112 value to zero of <em>any</em> type, including scalar and
2113 <a href="#t_aggregate">aggregate</a> types.
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2114 This is often used to avoid having to print large zero initializers
2115 (e.g. for large arrays) and is always exactly equivalent to using explicit
2116 zero initializers.</dd>
Nick Lewycky49f89192009-04-04 07:22:01 +0000[diff] [blame]2117
2118 <dt><b>Metadata node</b></dt>
Nick Lewycky8e2c4f42009-05-30 16:08:30 +0000[diff] [blame]2119 <dd>A metadata node is a structure-like constant with
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2120 <a href="#t_metadata">metadata type</a>. For example: "<tt>metadata !{
2121 i32 0, metadata !"test" }</tt>". Unlike other constants that are meant to
2122 be interpreted as part of the instruction stream, metadata is a place to
2123 attach additional information such as debug info.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2124</dl>
2125
2126</div>
2127
2128<!-- ======================================================================= -->
2129<div class="doc_subsection">
2130 <a name="globalconstants">Global Variable and Function Addresses</a>
2131</div>
2132
2133<div class="doc_text">
2134
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2135<p>The addresses of <a href="#globalvars">global variables</a>
2136 and <a href="#functionstructure">functions</a> are always implicitly valid
2137 (link-time) constants. These constants are explicitly referenced when
2138 the <a href="#identifiers">identifier for the global</a> is used and always
2139 have <a href="#t_pointer">pointer</a> type. For example, the following is a
2140 legal LLVM file:</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2141
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2142<pre class="doc_code">
Chris Lattner00538a12007-06-06 18:28:13 +0000[diff] [blame]2143@X = global i32 17
2144@Y = global i32 42
2145@Z = global [2 x i32*] [ i32* @X, i32* @Y ]
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2146</pre>
2147
2148</div>
2149
2150<!-- ======================================================================= -->
Reid Spencer641f5c92004-12-09 18:13:12 +0000[diff] [blame]2151<div class="doc_subsection"><a name="undefvalues">Undefined Values</a></div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2152<div class="doc_text">
2153
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2154<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]2155 indicates that the user of the value may receive an unspecified bit-pattern.
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2156 Undefined values may be of any type (other than label or void) and be used
2157 anywhere a constant is permitted.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2158
Chris Lattner92ada5d2009-09-11 01:49:31 +0000[diff] [blame]2159<p>Undefined values are useful because they indicate to the compiler that the
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2160 program is well defined no matter what value is used. This gives the
2161 compiler more freedom to optimize. Here are some examples of (potentially
2162 surprising) transformations that are valid (in pseudo IR):</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2163
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2164
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2165<pre class="doc_code">
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2166 %A = add %X, undef
2167 %B = sub %X, undef
2168 %C = xor %X, undef
2169Safe:
2170 %A = undef
2171 %B = undef
2172 %C = undef
2173</pre>
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2174
2175<p>This is safe because all of the output bits are affected by the undef bits.
2176Any output bit can have a zero or one depending on the input bits.</p>
2177
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2178<pre class="doc_code">
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2179 %A = or %X, undef
2180 %B = and %X, undef
2181Safe:
2182 %A = -1
2183 %B = 0
2184Unsafe:
2185 %A = undef
2186 %B = undef
2187</pre>
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2188
2189<p>These logical operations have bits that are not always affected by the input.
2190For example, if "%X" has a zero bit, then the output of the 'and' operation will
2191always be a zero, no matter what the corresponding bit from the undef is. As
Chris Lattner92ada5d2009-09-11 01:49:31 +0000[diff] [blame]2192such, it is unsafe to optimize or assume that the result of the and is undef.
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]2193However, it is safe to assume that all bits of the undef could be 0, and
2194optimize the and to 0. Likewise, it is safe to assume that all the bits of
2195the undef operand to the or could be set, allowing the or to be folded to
Chris Lattner92ada5d2009-09-11 01:49:31 +0000[diff] [blame]2196-1.</p>
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2197
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2198<pre class="doc_code">
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2199 %A = select undef, %X, %Y
2200 %B = select undef, 42, %Y
2201 %C = select %X, %Y, undef
2202Safe:
2203 %A = %X (or %Y)
2204 %B = 42 (or %Y)
2205 %C = %Y
2206Unsafe:
2207 %A = undef
2208 %B = undef
2209 %C = undef
2210</pre>
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2211
2212<p>This set of examples show that undefined select (and conditional branch)
2213conditions can go "either way" but they have to come from one of the two
2214operands. In the %A example, if %X and %Y were both known to have a clear low
2215bit, then %A would have to have a cleared low bit. However, in the %C example,
2216the optimizer is allowed to assume that the undef operand could be the same as
2217%Y, allowing the whole select to be eliminated.</p>
2218
2219
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2220<pre class="doc_code">
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2221 %A = xor undef, undef
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]2222
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2223 %B = undef
2224 %C = xor %B, %B
2225
2226 %D = undef
2227 %E = icmp lt %D, 4
2228 %F = icmp gte %D, 4
2229
2230Safe:
2231 %A = undef
2232 %B = undef
2233 %C = undef
2234 %D = undef
2235 %E = undef
2236 %F = undef
2237</pre>
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2238
2239<p>This example points out that two undef operands are not necessarily the same.
2240This can be surprising to people (and also matches C semantics) where they
2241assume that "X^X" is always zero, even if X is undef. This isn't true for a
2242number of reasons, but the short answer is that an undef "variable" can
2243arbitrarily change its value over its "live range". This is true because the
2244"variable" doesn't actually <em>have a live range</em>. Instead, the value is
2245logically read from arbitrary registers that happen to be around when needed,
Benjamin Kramer0f420382009-10-12 14:46:08 +0000[diff] [blame]2246so the value is not necessarily consistent over time. In fact, %A and %C need
Chris Lattner6760e542009-09-08 15:13:16 +0000[diff] [blame]2247to have the same semantics or the core LLVM "replace all uses with" concept
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2248would not hold.</p>
Chris Lattnera34a7182009-09-07 23:33:52 +0000[diff] [blame]2249
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2250<pre class="doc_code">
Chris Lattnera34a7182009-09-07 23:33:52 +0000[diff] [blame]2251 %A = fdiv undef, %X
2252 %B = fdiv %X, undef
2253Safe:
2254 %A = undef
2255b: unreachable
2256</pre>
Chris Lattnera34a7182009-09-07 23:33:52 +0000[diff] [blame]2257
2258<p>These examples show the crucial difference between an <em>undefined
2259value</em> and <em>undefined behavior</em>. An undefined value (like undef) is
2260allowed to have an arbitrary bit-pattern. This means that the %A operation
2261can be constant folded to undef because the undef could be an SNaN, and fdiv is
2262not (currently) defined on SNaN's. However, in the second example, we can make
2263a more aggressive assumption: because the undef is allowed to be an arbitrary
2264value, we are allowed to assume that it could be zero. Since a divide by zero
Chris Lattner10ff0c12009-09-08 19:45:34 +0000[diff] [blame]2265has <em>undefined behavior</em>, we are allowed to assume that the operation
Chris Lattnera34a7182009-09-07 23:33:52 +0000[diff] [blame]2266does not execute at all. This allows us to delete the divide and all code after
2267it: since the undefined operation "can't happen", the optimizer can assume that
2268it occurs in dead code.
2269</p>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]2270
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2271<pre class="doc_code">
Chris Lattnera34a7182009-09-07 23:33:52 +0000[diff] [blame]2272a: store undef -> %X
2273b: store %X -> undef
2274Safe:
2275a: &lt;deleted&gt;
2276b: unreachable
2277</pre>
Chris Lattnera34a7182009-09-07 23:33:52 +0000[diff] [blame]2278
2279<p>These examples reiterate the fdiv example: a store "of" an undefined value
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]2280can be assumed to not have any effect: we can assume that the value is
Chris Lattnera34a7182009-09-07 23:33:52 +0000[diff] [blame]2281overwritten with bits that happen to match what was already there. However, a
2282store "to" an undefined location could clobber arbitrary memory, therefore, it
2283has undefined behavior.</p>
2284
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2285</div>
2286
2287<!-- ======================================================================= -->
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]2288<div class="doc_subsection"><a name="trapvalues">Trap Values</a></div>
2289<div class="doc_text">
2290
Dan Gohmanb2a709b2010-04-26 20:21:21 +0000[diff] [blame]2291<p>Trap values are similar to <a href="#undefvalues">undef values</a>, however
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]2292 instead of representing an unspecified bit pattern, they represent the
2293 fact that an instruction or constant expression which cannot evoke side
2294 effects has nevertheless detected a condition which results in undefined
Dan Gohmanb2a709b2010-04-26 20:21:21 +0000[diff] [blame]2295 behavior.</p>
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]2296
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2297<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]2298 only exist when produced by operations such as
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2299 <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]2300
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2301<p>Trap value behavior is defined in terms of value <i>dependence</i>:</p>
Dan Gohmanb8b85c12010-04-26 23:36:52 +0000[diff] [blame]2302
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2303<ul>
2304<li>Values other than <a href="#i_phi"><tt>phi</tt></a> nodes depend on
2305 their operands.</li>
2306
2307<li><a href="#i_phi"><tt>Phi</tt></a> nodes depend on the operand corresponding
2308 to their dynamic predecessor basic block.</li>
2309
2310<li>Function arguments depend on the corresponding actual argument values in
2311 the dynamic callers of their functions.</li>
2312
2313<li><a href="#i_call"><tt>Call</tt></a> instructions depend on the
2314 <a href="#i_ret"><tt>ret</tt></a> instructions that dynamically transfer
2315 control back to them.</li>
2316
Dan Gohman7292a752010-05-03 14:55:22 +0000[diff] [blame]2317<li><a href="#i_invoke"><tt>Invoke</tt></a> instructions depend on the
2318 <a href="#i_ret"><tt>ret</tt></a>, <a href="#i_unwind"><tt>unwind</tt></a>,
2319 or exception-throwing call instructions that dynamically transfer control
2320 back to them.</li>
2321
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2322<li>Non-volatile loads and stores depend on the most recent stores to all of the
2323 referenced memory addresses, following the order in the IR
2324 (including loads and stores implied by intrinsics such as
2325 <a href="#int_memcpy"><tt>@llvm.memcpy</tt></a>.)</li>
2326
Dan Gohman3513ea52010-05-03 14:59:34 +0000[diff] [blame]2327<!-- TODO: In the case of multiple threads, this only applies if the store
2328 "happens-before" the load or store. -->
Dan Gohmanb8b85c12010-04-26 23:36:52 +0000[diff] [blame]2329
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2330<!-- TODO: floating-point exception state -->
Dan Gohmanb8b85c12010-04-26 23:36:52 +0000[diff] [blame]2331
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2332<li>An instruction with externally visible side effects depends on the most
2333 recent preceding instruction with externally visible side effects, following
Dan Gohman6c858db2010-07-06 15:26:33 +0000[diff] [blame]2334 the order in the IR. (This includes
2335 <a href="#volatile">volatile operations</a>.)</li>
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]2336
Dan Gohman7292a752010-05-03 14:55:22 +0000[diff] [blame]2337<li>An instruction <i>control-depends</i> on a
2338 <a href="#terminators">terminator instruction</a>
2339 if the terminator instruction has multiple successors and the instruction
2340 is always executed when control transfers to one of the successors, and
2341 may not be executed when control is transfered to another.</li>
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2342
2343<li>Dependence is transitive.</li>
2344
2345</ul>
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2346
2347<p>Whenever a trap value is generated, all values which depend on it evaluate
2348 to trap. If they have side effects, the evoke their side effects as if each
2349 operand with a trap value were undef. If they have externally-visible side
2350 effects, the behavior is undefined.</p>
2351
2352<p>Here are some examples:</p>
Dan Gohman48a25882010-04-26 20:54:53 +0000[diff] [blame]2353
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2354<pre class="doc_code">
Dan Gohmanb8b85c12010-04-26 23:36:52 +0000[diff] [blame]2355entry:
2356 %trap = sub nuw i32 0, 1 ; Results in a trap value.
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2357 %still_trap = and i32 %trap, 0 ; Whereas (and i32 undef, 0) would return 0.
2358 %trap_yet_again = getelementptr i32* @h, i32 %still_trap
2359 store i32 0, i32* %trap_yet_again ; undefined behavior
2360
2361 store i32 %trap, i32* @g ; Trap value conceptually stored to memory.
2362 %trap2 = load i32* @g ; Returns a trap value, not just undef.
2363
2364 volatile store i32 %trap, i32* @g ; External observation; undefined behavior.
2365
2366 %narrowaddr = bitcast i32* @g to i16*
2367 %wideaddr = bitcast i32* @g to i64*
2368 %trap3 = load 16* %narrowaddr ; Returns a trap value.
2369 %trap4 = load i64* %widaddr ; Returns a trap value.
2370
2371 %cmp = icmp i32 slt %trap, 0 ; Returns a trap value.
Dan Gohmanb8b85c12010-04-26 23:36:52 +0000[diff] [blame]2372 %br i1 %cmp, %true, %end ; Branch to either destination.
2373
2374true:
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2375 volatile store i32 0, i32* @g ; This is control-dependent on %cmp, so
2376 ; it has undefined behavior.
Dan Gohmanb8b85c12010-04-26 23:36:52 +0000[diff] [blame]2377 br label %end
2378
2379end:
2380 %p = phi i32 [ 0, %entry ], [ 1, %true ]
2381 ; Both edges into this PHI are
2382 ; control-dependent on %cmp, so this
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2383 ; always results in a trap value.
Dan Gohmanb8b85c12010-04-26 23:36:52 +0000[diff] [blame]2384
2385 volatile store i32 0, i32* @g ; %end is control-equivalent to %entry
2386 ; so this is defined (ignoring earlier
2387 ; undefined behavior in this example).
Dan Gohmanb8b85c12010-04-26 23:36:52 +0000[diff] [blame]2388</pre>
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]2389
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]2390</div>
2391
2392<!-- ======================================================================= -->
Chris Lattner2bfd3202009-10-27 21:19:13 +0000[diff] [blame]2393<div class="doc_subsection"><a name="blockaddress">Addresses of Basic
2394 Blocks</a></div>
Chris Lattnere4801f72009-10-27 21:01:34 +0000[diff] [blame]2395<div class="doc_text">
2396
Chris Lattneraa99c942009-11-01 01:27:45 +0000[diff] [blame]2397<p><b><tt>blockaddress(@function, %block)</tt></b></p>
Chris Lattnere4801f72009-10-27 21:01:34 +0000[diff] [blame]2398
2399<p>The '<tt>blockaddress</tt>' constant computes the address of the specified
Chris Lattner5c5f0ac2009-10-27 21:49:40 +0000[diff] [blame]2400 basic block in the specified function, and always has an i8* type. Taking
Chris Lattneraa99c942009-11-01 01:27:45 +0000[diff] [blame]2401 the address of the entry block is illegal.</p>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]2402
Chris Lattnere4801f72009-10-27 21:01:34 +0000[diff] [blame]2403<p>This value only has defined behavior when used as an operand to the
Chris Lattnerd04cb6d2009-10-28 00:19:10 +0000[diff] [blame]2404 '<a href="#i_indirectbr"><tt>indirectbr</tt></a>' instruction or for comparisons
Chris Lattnere4801f72009-10-27 21:01:34 +0000[diff] [blame]2405 against null. Pointer equality tests between labels addresses is undefined
2406 behavior - though, again, comparison against null is ok, and no label is
Chris Lattner2bfd3202009-10-27 21:19:13 +0000[diff] [blame]2407 equal to the null pointer. This may also be passed around as an opaque
2408 pointer sized value as long as the bits are not inspected. This allows
Chris Lattnerda37b302009-10-27 21:44:20 +0000[diff] [blame]2409 <tt>ptrtoint</tt> and arithmetic to be performed on these values so long as
Chris Lattnerd04cb6d2009-10-28 00:19:10 +0000[diff] [blame]2410 the original value is reconstituted before the <tt>indirectbr</tt>.</p>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]2411
Chris Lattner2bfd3202009-10-27 21:19:13 +0000[diff] [blame]2412<p>Finally, some targets may provide defined semantics when
Chris Lattnere4801f72009-10-27 21:01:34 +0000[diff] [blame]2413 using the value as the operand to an inline assembly, but that is target
2414 specific.
2415 </p>
2416
2417</div>
2418
2419
2420<!-- ======================================================================= -->
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2421<div class="doc_subsection"><a name="constantexprs">Constant Expressions</a>
2422</div>
2423
2424<div class="doc_text">
2425
2426<p>Constant expressions are used to allow expressions involving other constants
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2427 to be used as constants. Constant expressions may be of
2428 any <a href="#t_firstclass">first class</a> type and may involve any LLVM
2429 operation that does not have side effects (e.g. load and call are not
2430 supported). The following is the syntax for constant expressions:</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2431
2432<dl>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2433 <dt><b><tt>trunc (CST to TYPE)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2434 <dd>Truncate a constant to another type. The bit size of CST must be larger
2435 than the bit size of TYPE. Both types must be integers.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2436
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2437 <dt><b><tt>zext (CST to TYPE)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2438 <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]2439 smaller than the bit size of TYPE. Both types must be integers.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2440
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2441 <dt><b><tt>sext (CST to TYPE)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2442 <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]2443 smaller than the bit size of TYPE. Both types must be integers.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2444
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2445 <dt><b><tt>fptrunc (CST to TYPE)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2446 <dd>Truncate a floating point constant to another floating point type. The
2447 size of CST must be larger than the size of TYPE. Both types must be
2448 floating point.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2449
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2450 <dt><b><tt>fpext (CST to TYPE)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2451 <dd>Floating point extend a constant to another type. The size of CST must be
2452 smaller or equal to the size of TYPE. Both types must be floating
2453 point.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2454
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2455 <dt><b><tt>fptoui (CST to TYPE)</tt></b></dt>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2456 <dd>Convert a floating point constant to the corresponding unsigned integer
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2457 constant. TYPE must be a scalar or vector integer type. CST must be of
2458 scalar or vector floating point type. Both CST and TYPE must be scalars,
2459 or vectors of the same number of elements. If the value won't fit in the
2460 integer type, the results are undefined.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2461
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2462 <dt><b><tt>fptosi (CST to TYPE)</tt></b></dt>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2463 <dd>Convert a floating point constant to the corresponding signed integer
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2464 constant. TYPE must be a scalar or vector integer type. CST must be of
2465 scalar or vector floating point type. Both CST and TYPE must be scalars,
2466 or vectors of the same number of elements. If the value won't fit in the
2467 integer type, the results are undefined.</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>uitofp (CST to TYPE)</tt></b></dt>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2470 <dd>Convert an unsigned integer constant to the corresponding floating point
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2471 constant. TYPE must be a scalar or vector floating point type. CST must be
2472 of scalar or vector integer type. Both CST and TYPE must be scalars, or
2473 vectors of the same number of elements. If the value won't fit in the
2474 floating point type, the results are undefined.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2475
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2476 <dt><b><tt>sitofp (CST to TYPE)</tt></b></dt>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2477 <dd>Convert a signed integer constant to the corresponding floating point
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2478 constant. TYPE must be a scalar or vector floating point type. CST must be
2479 of scalar or vector integer type. Both CST and TYPE must be scalars, or
2480 vectors of the same number of elements. If the value won't fit in the
2481 floating point type, the results are undefined.</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>ptrtoint (CST to TYPE)</tt></b></dt>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]2484 <dd>Convert a pointer typed constant to the corresponding integer constant
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2485 <tt>TYPE</tt> must be an integer type. <tt>CST</tt> must be of pointer
2486 type. The <tt>CST</tt> value is zero extended, truncated, or unchanged to
2487 make it fit in <tt>TYPE</tt>.</dd>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]2488
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2489 <dt><b><tt>inttoptr (CST to TYPE)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2490 <dd>Convert a integer constant to a pointer constant. TYPE must be a pointer
2491 type. CST must be of integer type. The CST value is zero extended,
2492 truncated, or unchanged to make it fit in a pointer size. This one is
2493 <i>really</i> dangerous!</dd>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]2494
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2495 <dt><b><tt>bitcast (CST to TYPE)</tt></b></dt>
Chris Lattner789dee32009-02-28 18:27:03 +0000[diff] [blame]2496 <dd>Convert a constant, CST, to another TYPE. The constraints of the operands
2497 are the same as those for the <a href="#i_bitcast">bitcast
2498 instruction</a>.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2499
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2500 <dt><b><tt>getelementptr (CSTPTR, IDX0, IDX1, ...)</tt></b></dt>
2501 <dt><b><tt>getelementptr inbounds (CSTPTR, IDX0, IDX1, ...)</tt></b></dt>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2502 <dd>Perform the <a href="#i_getelementptr">getelementptr operation</a> on
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2503 constants. As with the <a href="#i_getelementptr">getelementptr</a>
2504 instruction, the index list may have zero or more indexes, which are
2505 required to make sense for the type of "CSTPTR".</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2506
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2507 <dt><b><tt>select (COND, VAL1, VAL2)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2508 <dd>Perform the <a href="#i_select">select operation</a> on constants.</dd>
Reid Spencer9965ee72006-12-04 19:23:19 +0000[diff] [blame]2509
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2510 <dt><b><tt>icmp COND (VAL1, VAL2)</tt></b></dt>
Reid Spencer9965ee72006-12-04 19:23:19 +0000[diff] [blame]2511 <dd>Performs the <a href="#i_icmp">icmp operation</a> on constants.</dd>
2512
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2513 <dt><b><tt>fcmp COND (VAL1, VAL2)</tt></b></dt>
Reid Spencer9965ee72006-12-04 19:23:19 +0000[diff] [blame]2514 <dd>Performs the <a href="#i_fcmp">fcmp operation</a> on constants.</dd>
Robert Bocchino7e97a6d2006-01-10 19:31:34 +0000[diff] [blame]2515
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2516 <dt><b><tt>extractelement (VAL, IDX)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2517 <dd>Perform the <a href="#i_extractelement">extractelement operation</a> on
2518 constants.</dd>
Robert Bocchino7e97a6d2006-01-10 19:31:34 +0000[diff] [blame]2519
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2520 <dt><b><tt>insertelement (VAL, ELT, IDX)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2521 <dd>Perform the <a href="#i_insertelement">insertelement operation</a> on
2522 constants.</dd>
Chris Lattner016a0e52006-04-08 00:13:41 +0000[diff] [blame]2523
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2524 <dt><b><tt>shufflevector (VEC1, VEC2, IDXMASK)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2525 <dd>Perform the <a href="#i_shufflevector">shufflevector operation</a> on
2526 constants.</dd>
Chris Lattner016a0e52006-04-08 00:13:41 +0000[diff] [blame]2527
Nick Lewycky9ab9a7f2010-05-29 06:44:15 +0000[diff] [blame]2528 <dt><b><tt>extractvalue (VAL, IDX0, IDX1, ...)</tt></b></dt>
2529 <dd>Perform the <a href="#i_extractvalue">extractvalue operation</a> on
2530 constants. The index list is interpreted in a similar manner as indices in
2531 a '<a href="#i_getelementptr">getelementptr</a>' operation. At least one
2532 index value must be specified.</dd>
2533
2534 <dt><b><tt>insertvalue (VAL, ELT, IDX0, IDX1, ...)</tt></b></dt>
2535 <dd>Perform the <a href="#i_insertvalue">insertvalue operation</a> on
2536 constants. The index list is interpreted in a similar manner as indices in
2537 a '<a href="#i_getelementptr">getelementptr</a>' operation. At least one
2538 index value must be specified.</dd>
2539
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2540 <dt><b><tt>OPCODE (LHS, RHS)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2541 <dd>Perform the specified operation of the LHS and RHS constants. OPCODE may
2542 be any of the <a href="#binaryops">binary</a>
2543 or <a href="#bitwiseops">bitwise binary</a> operations. The constraints
2544 on operands are the same as those for the corresponding instruction
2545 (e.g. no bitwise operations on floating point values are allowed).</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2546</dl>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2547
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2548</div>
Chris Lattnerb1652612004-03-08 16:49:10 +0000[diff] [blame]2549
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2550<!-- *********************************************************************** -->
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2551<div class="doc_section"> <a name="othervalues">Other Values</a> </div>
2552<!-- *********************************************************************** -->
2553
2554<!-- ======================================================================= -->
2555<div class="doc_subsection">
2556<a name="inlineasm">Inline Assembler Expressions</a>
2557</div>
2558
2559<div class="doc_text">
2560
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2561<p>LLVM supports inline assembler expressions (as opposed
2562 to <a href="#moduleasm"> Module-Level Inline Assembly</a>) through the use of
2563 a special value. This value represents the inline assembler as a string
2564 (containing the instructions to emit), a list of operand constraints (stored
Dale Johannesen63c94fe2009-10-13 21:56:55 +0000[diff] [blame]2565 as a string), a flag that indicates whether or not the inline asm
Dale Johannesen1cfb9582009-10-21 23:28:00 +0000[diff] [blame]2566 expression has side effects, and a flag indicating whether the function
2567 containing the asm needs to align its stack conservatively. An example
2568 inline assembler expression is:</p>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2569
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2570<pre class="doc_code">
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2571i32 (i32) asm "bswap $0", "=r,r"
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2572</pre>
2573
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2574<p>Inline assembler expressions may <b>only</b> be used as the callee operand of
2575 a <a href="#i_call"><tt>call</tt> instruction</a>. Thus, typically we
2576 have:</p>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2577
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2578<pre class="doc_code">
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2579%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]2580</pre>
2581
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2582<p>Inline asms with side effects not visible in the constraint list must be
2583 marked as having side effects. This is done through the use of the
2584 '<tt>sideeffect</tt>' keyword, like so:</p>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2585
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2586<pre class="doc_code">
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2587call void asm sideeffect "eieio", ""()
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2588</pre>
2589
Dale Johannesen1cfb9582009-10-21 23:28:00 +0000[diff] [blame]2590<p>In some cases inline asms will contain code that will not work unless the
2591 stack is aligned in some way, such as calls or SSE instructions on x86,
2592 yet will not contain code that does that alignment within the asm.
2593 The compiler should make conservative assumptions about what the asm might
2594 contain and should generate its usual stack alignment code in the prologue
2595 if the '<tt>alignstack</tt>' keyword is present:</p>
Dale Johannesen63c94fe2009-10-13 21:56:55 +0000[diff] [blame]2596
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2597<pre class="doc_code">
Dale Johannesen1cfb9582009-10-21 23:28:00 +0000[diff] [blame]2598call void asm alignstack "eieio", ""()
Dale Johannesen63c94fe2009-10-13 21:56:55 +0000[diff] [blame]2599</pre>
Dale Johannesen63c94fe2009-10-13 21:56:55 +0000[diff] [blame]2600
2601<p>If both keywords appear the '<tt>sideeffect</tt>' keyword must come
2602 first.</p>
2603
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2604<p>TODO: The format of the asm and constraints string still need to be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2605 documented here. Constraints on what can be done (e.g. duplication, moving,
2606 etc need to be documented). This is probably best done by reference to
2607 another document that covers inline asm from a holistic perspective.</p>
Chris Lattner51065562010-04-07 05:38:05 +0000[diff] [blame]2608</div>
2609
2610<div class="doc_subsubsection">
2611<a name="inlineasm_md">Inline Asm Metadata</a>
2612</div>
2613
2614<div class="doc_text">
2615
2616<p>The call instructions that wrap inline asm nodes may have a "!srcloc" MDNode
2617 attached to it that contains a constant integer. If present, the code
2618 generator will use the integer as the location cookie value when report
2619 errors through the LLVMContext error reporting mechanisms. This allows a
Dan Gohman61110ae2010-04-28 00:36:01 +0000[diff] [blame]2620 front-end to correlate backend errors that occur with inline asm back to the
Chris Lattner51065562010-04-07 05:38:05 +0000[diff] [blame]2621 source code that produced it. For example:</p>
2622
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2623<pre class="doc_code">
Chris Lattner51065562010-04-07 05:38:05 +0000[diff] [blame]2624call void asm sideeffect "something bad", ""()<b>, !srcloc !42</b>
2625...
2626!42 = !{ i32 1234567 }
2627</pre>
Chris Lattner51065562010-04-07 05:38:05 +0000[diff] [blame]2628
2629<p>It is up to the front-end to make sense of the magic numbers it places in the
2630 IR.</p>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2631
2632</div>
2633
Chris Lattnerc2f8f162010-01-15 21:50:19 +0000[diff] [blame]2634<!-- ======================================================================= -->
2635<div class="doc_subsection"><a name="metadata">Metadata Nodes and Metadata
2636 Strings</a>
2637</div>
2638
2639<div class="doc_text">
2640
2641<p>LLVM IR allows metadata to be attached to instructions in the program that
2642 can convey extra information about the code to the optimizers and code
2643 generator. One example application of metadata is source-level debug
2644 information. There are two metadata primitives: strings and nodes. All
2645 metadata has the <tt>metadata</tt> type and is identified in syntax by a
2646 preceding exclamation point ('<tt>!</tt>').</p>
2647
2648<p>A metadata string is a string surrounded by double quotes. It can contain
2649 any character by escaping non-printable characters with "\xx" where "xx" is
2650 the two digit hex code. For example: "<tt>!"test\00"</tt>".</p>
2651
2652<p>Metadata nodes are represented with notation similar to structure constants
2653 (a comma separated list of elements, surrounded by braces and preceded by an
2654 exclamation point). For example: "<tt>!{ metadata !"test\00", i32
2655 10}</tt>". Metadata nodes can have any values as their operand.</p>
2656
2657<p>A <a href="#namedmetadatastructure">named metadata</a> is a collection of
2658 metadata nodes, which can be looked up in the module symbol table. For
2659 example: "<tt>!foo = metadata !{!4, !3}</tt>".
2660
Devang Patel9984bd62010-03-04 23:44:48 +0000[diff] [blame]2661<p>Metadata can be used as function arguments. Here <tt>llvm.dbg.value</tt>
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2662 function is using two metadata arguments.</p>
Devang Patel9984bd62010-03-04 23:44:48 +0000[diff] [blame]2663
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2664 <pre class="doc_code">
Devang Patel9984bd62010-03-04 23:44:48 +0000[diff] [blame]2665 call void @llvm.dbg.value(metadata !24, i64 0, metadata !25)
2666 </pre>
Devang Patel9984bd62010-03-04 23:44:48 +0000[diff] [blame]2667
2668<p>Metadata can be attached with an instruction. Here metadata <tt>!21</tt> is
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2669 attached with <tt>add</tt> instruction using <tt>!dbg</tt> identifier.</p>
Devang Patel9984bd62010-03-04 23:44:48 +0000[diff] [blame]2670
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2671 <pre class="doc_code">
Devang Patel9984bd62010-03-04 23:44:48 +0000[diff] [blame]2672 %indvar.next = add i64 %indvar, 1, !dbg !21
2673 </pre>
Chris Lattnerc2f8f162010-01-15 21:50:19 +0000[diff] [blame]2674</div>
2675
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]2676
2677<!-- *********************************************************************** -->
2678<div class="doc_section">
2679 <a name="intrinsic_globals">Intrinsic Global Variables</a>
2680</div>
2681<!-- *********************************************************************** -->
2682
2683<p>LLVM has a number of "magic" global variables that contain data that affect
2684code generation or other IR semantics. These are documented here. All globals
Chris Lattner58f9bb22009-07-20 06:14:25 +0000[diff] [blame]2685of this sort should have a section specified as "<tt>llvm.metadata</tt>". This
2686section and all globals that start with "<tt>llvm.</tt>" are reserved for use
2687by LLVM.</p>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]2688
2689<!-- ======================================================================= -->
2690<div class="doc_subsection">
2691<a name="intg_used">The '<tt>llvm.used</tt>' Global Variable</a>
2692</div>
2693
2694<div class="doc_text">
2695
2696<p>The <tt>@llvm.used</tt> global is an array with i8* element type which has <a
2697href="#linkage_appending">appending linkage</a>. This array contains a list of
2698pointers to global variables and functions which may optionally have a pointer
2699cast formed of bitcast or getelementptr. For example, a legal use of it is:</p>
2700
2701<pre>
2702 @X = global i8 4
2703 @Y = global i32 123
2704
2705 @llvm.used = appending global [2 x i8*] [
2706 i8* @X,
2707 i8* bitcast (i32* @Y to i8*)
2708 ], section "llvm.metadata"
2709</pre>
2710
2711<p>If a global variable appears in the <tt>@llvm.used</tt> list, then the
2712compiler, assembler, and linker are required to treat the symbol as if there is
2713a reference to the global that it cannot see. For example, if a variable has
2714internal linkage and no references other than that from the <tt>@llvm.used</tt>
2715list, it cannot be deleted. This is commonly used to represent references from
2716inline asms and other things the compiler cannot "see", and corresponds to
2717"attribute((used))" in GNU C.</p>
2718
2719<p>On some targets, the code generator must emit a directive to the assembler or
2720object file to prevent the assembler and linker from molesting the symbol.</p>
2721
2722</div>
2723
2724<!-- ======================================================================= -->
2725<div class="doc_subsection">
Chris Lattner58f9bb22009-07-20 06:14:25 +0000[diff] [blame]2726<a name="intg_compiler_used">The '<tt>llvm.compiler.used</tt>' Global Variable</a>
2727</div>
2728
2729<div class="doc_text">
2730
2731<p>The <tt>@llvm.compiler.used</tt> directive is the same as the
2732<tt>@llvm.used</tt> directive, except that it only prevents the compiler from
2733touching the symbol. On targets that support it, this allows an intelligent
2734linker to optimize references to the symbol without being impeded as it would be
2735by <tt>@llvm.used</tt>.</p>
2736
2737<p>This is a rare construct that should only be used in rare circumstances, and
2738should not be exposed to source languages.</p>
2739
2740</div>
2741
2742<!-- ======================================================================= -->
2743<div class="doc_subsection">
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]2744<a name="intg_global_ctors">The '<tt>llvm.global_ctors</tt>' Global Variable</a>
2745</div>
2746
2747<div class="doc_text">
David Chisnalla9d4a6f2010-04-30 19:23:49 +0000[diff] [blame]2748<pre>
2749%0 = type { i32, void ()* }
David Chisnallb492b812010-04-30 19:27:35 +0000[diff] [blame]2750@llvm.global_ctors = appending global [1 x %0] [%0 { i32 65535, void ()* @ctor }]
David Chisnalla9d4a6f2010-04-30 19:23:49 +0000[diff] [blame]2751</pre>
2752<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.
2753</p>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]2754
2755</div>
2756
2757<!-- ======================================================================= -->
2758<div class="doc_subsection">
2759<a name="intg_global_dtors">The '<tt>llvm.global_dtors</tt>' Global Variable</a>
2760</div>
2761
2762<div class="doc_text">
David Chisnalla9d4a6f2010-04-30 19:23:49 +0000[diff] [blame]2763<pre>
2764%0 = type { i32, void ()* }
David Chisnallb492b812010-04-30 19:27:35 +0000[diff] [blame]2765@llvm.global_dtors = appending global [1 x %0] [%0 { i32 65535, void ()* @dtor }]
David Chisnalla9d4a6f2010-04-30 19:23:49 +0000[diff] [blame]2766</pre>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]2767
David Chisnalla9d4a6f2010-04-30 19:23:49 +0000[diff] [blame]2768<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.
2769</p>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]2770
2771</div>
2772
2773
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2774<!-- *********************************************************************** -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2775<div class="doc_section"> <a name="instref">Instruction Reference</a> </div>
2776<!-- *********************************************************************** -->
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2777
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2778<div class="doc_text">
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2779
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2780<p>The LLVM instruction set consists of several different classifications of
2781 instructions: <a href="#terminators">terminator
2782 instructions</a>, <a href="#binaryops">binary instructions</a>,
2783 <a href="#bitwiseops">bitwise binary instructions</a>,
2784 <a href="#memoryops">memory instructions</a>, and
2785 <a href="#otherops">other instructions</a>.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2786
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2787</div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2788
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2789<!-- ======================================================================= -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2790<div class="doc_subsection"> <a name="terminators">Terminator
2791Instructions</a> </div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2792
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2793<div class="doc_text">
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2794
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2795<p>As mentioned <a href="#functionstructure">previously</a>, every basic block
2796 in a program ends with a "Terminator" instruction, which indicates which
2797 block should be executed after the current block is finished. These
2798 terminator instructions typically yield a '<tt>void</tt>' value: they produce
2799 control flow, not values (the one exception being the
2800 '<a href="#i_invoke"><tt>invoke</tt></a>' instruction).</p>
2801
Duncan Sands626b0242010-04-15 20:35:54 +0000[diff] [blame]2802<p>There are seven different terminator instructions: the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2803 '<a href="#i_ret"><tt>ret</tt></a>' instruction, the
2804 '<a href="#i_br"><tt>br</tt></a>' instruction, the
2805 '<a href="#i_switch"><tt>switch</tt></a>' instruction, the
Bill Wendling33fef7e2009-11-02 00:25:26 +0000[diff] [blame]2806 '<a href="#i_indirectbr">'<tt>indirectbr</tt></a>' Instruction, the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2807 '<a href="#i_invoke"><tt>invoke</tt></a>' instruction, the
2808 '<a href="#i_unwind"><tt>unwind</tt></a>' instruction, and the
2809 '<a href="#i_unreachable"><tt>unreachable</tt></a>' instruction.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2810
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2811</div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2812
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2813<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2814<div class="doc_subsubsection"> <a name="i_ret">'<tt>ret</tt>'
2815Instruction</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2816
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2817<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2818
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2819<h5>Syntax:</h5>
Dan Gohmancc3132e2008-10-04 19:00:07 +0000[diff] [blame]2820<pre>
2821 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]2822 ret void <i>; Return from void function</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2823</pre>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]2824
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2825<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2826<p>The '<tt>ret</tt>' instruction is used to return control flow (and optionally
2827 a value) from a function back to the caller.</p>
2828
2829<p>There are two forms of the '<tt>ret</tt>' instruction: one that returns a
2830 value and then causes control flow, and one that just causes control flow to
2831 occur.</p>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]2832
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2833<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2834<p>The '<tt>ret</tt>' instruction optionally accepts a single argument, the
2835 return value. The type of the return value must be a
2836 '<a href="#t_firstclass">first class</a>' type.</p>
Dan Gohmancc3132e2008-10-04 19:00:07 +0000[diff] [blame]2837
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2838<p>A function is not <a href="#wellformed">well formed</a> if it it has a
2839 non-void return type and contains a '<tt>ret</tt>' instruction with no return
2840 value or a return value with a type that does not match its type, or if it
2841 has a void return type and contains a '<tt>ret</tt>' instruction with a
2842 return value.</p>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]2843
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2844<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2845<p>When the '<tt>ret</tt>' instruction is executed, control flow returns back to
2846 the calling function's context. If the caller is a
2847 "<a href="#i_call"><tt>call</tt></a>" instruction, execution continues at the
2848 instruction after the call. If the caller was an
2849 "<a href="#i_invoke"><tt>invoke</tt></a>" instruction, execution continues at
2850 the beginning of the "normal" destination block. If the instruction returns
2851 a value, that value shall set the call or invoke instruction's return
2852 value.</p>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]2853
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2854<h5>Example:</h5>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]2855<pre>
2856 ret i32 5 <i>; Return an integer value of 5</i>
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]2857 ret void <i>; Return from a void function</i>
Bill Wendling050ee8f2009-02-28 22:12:54 +0000[diff] [blame]2858 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]2859</pre>
Dan Gohman3065b612009-01-12 23:12:39 +0000[diff] [blame]2860
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2861</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2862<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2863<div class="doc_subsubsection"> <a name="i_br">'<tt>br</tt>' Instruction</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2864
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2865<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2866
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2867<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2868<pre>
2869 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]2870</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2871
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2872<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2873<p>The '<tt>br</tt>' instruction is used to cause control flow to transfer to a
2874 different basic block in the current function. There are two forms of this
2875 instruction, corresponding to a conditional branch and an unconditional
2876 branch.</p>
2877
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2878<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2879<p>The conditional branch form of the '<tt>br</tt>' instruction takes a single
2880 '<tt>i1</tt>' value and two '<tt>label</tt>' values. The unconditional form
2881 of the '<tt>br</tt>' instruction takes a single '<tt>label</tt>' value as a
2882 target.</p>
2883
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2884<h5>Semantics:</h5>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]2885<p>Upon execution of a conditional '<tt>br</tt>' instruction, the '<tt>i1</tt>'
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2886 argument is evaluated. If the value is <tt>true</tt>, control flows to the
2887 '<tt>iftrue</tt>' <tt>label</tt> argument. If "cond" is <tt>false</tt>,
2888 control flows to the '<tt>iffalse</tt>' <tt>label</tt> argument.</p>
2889
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2890<h5>Example:</h5>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]2891<pre>
2892Test:
2893 %cond = <a href="#i_icmp">icmp</a> eq i32 %a, %b
2894 br i1 %cond, label %IfEqual, label %IfUnequal
2895IfEqual:
2896 <a href="#i_ret">ret</a> i32 1
2897IfUnequal:
2898 <a href="#i_ret">ret</a> i32 0
2899</pre>
2900
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2901</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2902
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2903<!-- _______________________________________________________________________ -->
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2904<div class="doc_subsubsection">
2905 <a name="i_switch">'<tt>switch</tt>' Instruction</a>
2906</div>
2907
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2908<div class="doc_text">
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2909
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2910<h5>Syntax:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2911<pre>
2912 switch &lt;intty&gt; &lt;value&gt;, label &lt;defaultdest&gt; [ &lt;intty&gt; &lt;val&gt;, label &lt;dest&gt; ... ]
2913</pre>
2914
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2915<h5>Overview:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2916<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]2917 several different places. It is a generalization of the '<tt>br</tt>'
2918 instruction, allowing a branch to occur to one of many possible
2919 destinations.</p>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2920
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2921<h5>Arguments:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2922<p>The '<tt>switch</tt>' instruction uses three parameters: an integer
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2923 comparison value '<tt>value</tt>', a default '<tt>label</tt>' destination,
2924 and an array of pairs of comparison value constants and '<tt>label</tt>'s.
2925 The table is not allowed to contain duplicate constant entries.</p>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2926
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2927<h5>Semantics:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2928<p>The <tt>switch</tt> instruction specifies a table of values and
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2929 destinations. When the '<tt>switch</tt>' instruction is executed, this table
2930 is searched for the given value. If the value is found, control flow is
Benjamin Kramer0f420382009-10-12 14:46:08 +0000[diff] [blame]2931 transferred to the corresponding destination; otherwise, control flow is
2932 transferred to the default destination.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2933
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2934<h5>Implementation:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2935<p>Depending on properties of the target machine and the particular
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2936 <tt>switch</tt> instruction, this instruction may be code generated in
2937 different ways. For example, it could be generated as a series of chained
2938 conditional branches or with a lookup table.</p>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2939
2940<h5>Example:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2941<pre>
2942 <i>; Emulate a conditional br instruction</i>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]2943 %Val = <a href="#i_zext">zext</a> i1 %value to i32
Dan Gohman623806e2009-01-04 23:44:43 +0000[diff] [blame]2944 switch i32 %Val, label %truedest [ i32 0, label %falsedest ]
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2945
2946 <i>; Emulate an unconditional br instruction</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2947 switch i32 0, label %dest [ ]
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2948
2949 <i>; Implement a jump table:</i>
Dan Gohman623806e2009-01-04 23:44:43 +0000[diff] [blame]2950 switch i32 %val, label %otherwise [ i32 0, label %onzero
2951 i32 1, label %onone
2952 i32 2, label %ontwo ]
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2953</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2954
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2955</div>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]2956
Chris Lattner3ed871f2009-10-27 19:13:16 +0000[diff] [blame]2957
2958<!-- _______________________________________________________________________ -->
2959<div class="doc_subsubsection">
Chris Lattnerd04cb6d2009-10-28 00:19:10 +0000[diff] [blame]2960 <a name="i_indirectbr">'<tt>indirectbr</tt>' Instruction</a>
Chris Lattner3ed871f2009-10-27 19:13:16 +0000[diff] [blame]2961</div>
2962
2963<div class="doc_text">
2964
2965<h5>Syntax:</h5>
2966<pre>
Chris Lattnerd04cb6d2009-10-28 00:19:10 +0000[diff] [blame]2967 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]2968</pre>
2969
2970<h5>Overview:</h5>
2971
Chris Lattnerd04cb6d2009-10-28 00:19:10 +0000[diff] [blame]2972<p>The '<tt>indirectbr</tt>' instruction implements an indirect branch to a label
Chris Lattner3ed871f2009-10-27 19:13:16 +0000[diff] [blame]2973 within the current function, whose address is specified by
Chris Lattnere4801f72009-10-27 21:01:34 +0000[diff] [blame]2974 "<tt>address</tt>". Address must be derived from a <a
2975 href="#blockaddress">blockaddress</a> constant.</p>
Chris Lattner3ed871f2009-10-27 19:13:16 +0000[diff] [blame]2976
2977<h5>Arguments:</h5>
2978
2979<p>The '<tt>address</tt>' argument is the address of the label to jump to. The
2980 rest of the arguments indicate the full set of possible destinations that the
2981 address may point to. Blocks are allowed to occur multiple times in the
2982 destination list, though this isn't particularly useful.</p>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]2983
Chris Lattner3ed871f2009-10-27 19:13:16 +0000[diff] [blame]2984<p>This destination list is required so that dataflow analysis has an accurate
2985 understanding of the CFG.</p>
2986
2987<h5>Semantics:</h5>
2988
2989<p>Control transfers to the block specified in the address argument. All
2990 possible destination blocks must be listed in the label list, otherwise this
2991 instruction has undefined behavior. This implies that jumps to labels
2992 defined in other functions have undefined behavior as well.</p>
2993
2994<h5>Implementation:</h5>
2995
2996<p>This is typically implemented with a jump through a register.</p>
2997
2998<h5>Example:</h5>
2999<pre>
Chris Lattnerd04cb6d2009-10-28 00:19:10 +0000[diff] [blame]3000 indirectbr i8* %Addr, [ label %bb1, label %bb2, label %bb3 ]
Chris Lattner3ed871f2009-10-27 19:13:16 +0000[diff] [blame]3001</pre>
3002
3003</div>
3004
3005
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3006<!-- _______________________________________________________________________ -->
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3007<div class="doc_subsubsection">
3008 <a name="i_invoke">'<tt>invoke</tt>' Instruction</a>
3009</div>
3010
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3011<div class="doc_text">
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3012
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3013<h5>Syntax:</h5>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3014<pre>
Devang Patel02256232008-10-07 17:48:33 +0000[diff] [blame]3015 &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]3016 to label &lt;normal label&gt; unwind label &lt;exception label&gt;
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3017</pre>
3018
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]3019<h5>Overview:</h5>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3020<p>The '<tt>invoke</tt>' instruction causes control to transfer to a specified
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3021 function, with the possibility of control flow transfer to either the
3022 '<tt>normal</tt>' label or the '<tt>exception</tt>' label. If the callee
3023 function returns with the "<tt><a href="#i_ret">ret</a></tt>" instruction,
3024 control flow will return to the "normal" label. If the callee (or any
3025 indirect callees) returns with the "<a href="#i_unwind"><tt>unwind</tt></a>"
3026 instruction, control is interrupted and continued at the dynamically nearest
3027 "exception" label.</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3028
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3029<h5>Arguments:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3030<p>This instruction requires several arguments:</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3031
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3032<ol>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3033 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
3034 convention</a> the call should use. If none is specified, the call
3035 defaults to using C calling conventions.</li>
Devang Patel7e9b05e2008-10-06 18:50:38 +0000[diff] [blame]3036
3037 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3038 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
3039 '<tt>inreg</tt>' attributes are valid here.</li>
Devang Patel7e9b05e2008-10-06 18:50:38 +0000[diff] [blame]3040
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3041 <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]3042 function value being invoked. In most cases, this is a direct function
3043 invocation, but indirect <tt>invoke</tt>s are just as possible, branching
3044 off an arbitrary pointer to function value.</li>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3045
3046 <li>'<tt>function ptr val</tt>': An LLVM value containing a pointer to a
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3047 function to be invoked. </li>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3048
3049 <li>'<tt>function args</tt>': argument list whose types match the function
Chris Lattner47f2a832010-03-02 06:36:51 +0000[diff] [blame]3050 signature argument types and parameter attributes. All arguments must be
3051 of <a href="#t_firstclass">first class</a> type. If the function
3052 signature indicates the function accepts a variable number of arguments,
3053 the extra arguments can be specified.</li>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3054
3055 <li>'<tt>normal label</tt>': the label reached when the called function
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3056 executes a '<tt><a href="#i_ret">ret</a></tt>' instruction. </li>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3057
3058 <li>'<tt>exception label</tt>': the label reached when a callee returns with
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3059 the <a href="#i_unwind"><tt>unwind</tt></a> instruction. </li>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3060
Devang Patel02256232008-10-07 17:48:33 +0000[diff] [blame]3061 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3062 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
3063 '<tt>readnone</tt>' attributes are valid here.</li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3064</ol>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3065
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3066<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3067<p>This instruction is designed to operate as a standard
3068 '<tt><a href="#i_call">call</a></tt>' instruction in most regards. The
3069 primary difference is that it establishes an association with a label, which
3070 is used by the runtime library to unwind the stack.</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3071
3072<p>This instruction is used in languages with destructors to ensure that proper
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3073 cleanup is performed in the case of either a <tt>longjmp</tt> or a thrown
3074 exception. Additionally, this is important for implementation of
3075 '<tt>catch</tt>' clauses in high-level languages that support them.</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3076
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3077<p>For the purposes of the SSA form, the definition of the value returned by the
3078 '<tt>invoke</tt>' instruction is deemed to occur on the edge from the current
3079 block to the "normal" label. If the callee unwinds then no return value is
3080 available.</p>
Dan Gohman9069d892009-05-22 21:47:08 +0000[diff] [blame]3081
Chris Lattner97257f82010-01-15 18:08:37 +0000[diff] [blame]3082<p>Note that the code generator does not yet completely support unwind, and
3083that the invoke/unwind semantics are likely to change in future versions.</p>
3084
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3085<h5>Example:</h5>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3086<pre>
Nick Lewycky084ab472008-03-16 07:18:12 +0000[diff] [blame]3087 %retval = invoke i32 @Test(i32 15) to label %Continue
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]3088 unwind label %TestCleanup <i>; {i32}:retval set</i>
Nick Lewycky084ab472008-03-16 07:18:12 +0000[diff] [blame]3089 %retval = invoke <a href="#callingconv">coldcc</a> i32 %Testfnptr(i32 15) to label %Continue
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]3090 unwind label %TestCleanup <i>; {i32}:retval set</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3091</pre>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3092
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3093</div>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3094
Chris Lattner5ed60612003-09-03 00:41:47 +0000[diff] [blame]3095<!-- _______________________________________________________________________ -->
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3096
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3097<div class="doc_subsubsection"> <a name="i_unwind">'<tt>unwind</tt>'
3098Instruction</a> </div>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3099
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3100<div class="doc_text">
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3101
Chris Lattner5ed60612003-09-03 00:41:47 +0000[diff] [blame]3102<h5>Syntax:</h5>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3103<pre>
3104 unwind
3105</pre>
3106
Chris Lattner5ed60612003-09-03 00:41:47 +0000[diff] [blame]3107<h5>Overview:</h5>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3108<p>The '<tt>unwind</tt>' instruction unwinds the stack, continuing control flow
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3109 at the first callee in the dynamic call stack which used
3110 an <a href="#i_invoke"><tt>invoke</tt></a> instruction to perform the call.
3111 This is primarily used to implement exception handling.</p>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3112
Chris Lattner5ed60612003-09-03 00:41:47 +0000[diff] [blame]3113<h5>Semantics:</h5>
Chris Lattnerfe8519c2008-04-19 21:01:16 +0000[diff] [blame]3114<p>The '<tt>unwind</tt>' instruction causes execution of the current function to
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3115 immediately halt. The dynamic call stack is then searched for the
3116 first <a href="#i_invoke"><tt>invoke</tt></a> instruction on the call stack.
3117 Once found, execution continues at the "exceptional" destination block
3118 specified by the <tt>invoke</tt> instruction. If there is no <tt>invoke</tt>
3119 instruction in the dynamic call chain, undefined behavior results.</p>
3120
Chris Lattner97257f82010-01-15 18:08:37 +0000[diff] [blame]3121<p>Note that the code generator does not yet completely support unwind, and
3122that the invoke/unwind semantics are likely to change in future versions.</p>
3123
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3124</div>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3125
3126<!-- _______________________________________________________________________ -->
3127
3128<div class="doc_subsubsection"> <a name="i_unreachable">'<tt>unreachable</tt>'
3129Instruction</a> </div>
3130
3131<div class="doc_text">
3132
3133<h5>Syntax:</h5>
3134<pre>
3135 unreachable
3136</pre>
3137
3138<h5>Overview:</h5>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3139<p>The '<tt>unreachable</tt>' instruction has no defined semantics. This
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3140 instruction is used to inform the optimizer that a particular portion of the
3141 code is not reachable. This can be used to indicate that the code after a
3142 no-return function cannot be reached, and other facts.</p>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3143
3144<h5>Semantics:</h5>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3145<p>The '<tt>unreachable</tt>' instruction has no defined semantics.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3146
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3147</div>
3148
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3149<!-- ======================================================================= -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3150<div class="doc_subsection"> <a name="binaryops">Binary Operations</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3151
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3152<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3153
3154<p>Binary operators are used to do most of the computation in a program. They
3155 require two operands of the same type, execute an operation on them, and
3156 produce a single value. The operands might represent multiple data, as is
3157 the case with the <a href="#t_vector">vector</a> data type. The result value
3158 has the same type as its operands.</p>
3159
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3160<p>There are several different binary operators:</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3161
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3162</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3163
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3164<!-- _______________________________________________________________________ -->
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3165<div class="doc_subsubsection">
3166 <a name="i_add">'<tt>add</tt>' Instruction</a>
3167</div>
3168
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3169<div class="doc_text">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3170
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3171<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3172<pre>
Dan Gohmanb07de442009-07-20 22:41:19 +0000[diff] [blame]3173 &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]3174 &lt;result&gt; = add nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3175 &lt;result&gt; = add nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3176 &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]3177</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3178
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3179<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3180<p>The '<tt>add</tt>' instruction returns the sum of its two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3181
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3182<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3183<p>The two arguments to the '<tt>add</tt>' instruction must
3184 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3185 integer values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3186
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3187<h5>Semantics:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3188<p>The value produced is the integer sum of the two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3189
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3190<p>If the sum has unsigned overflow, the result returned is the mathematical
3191 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]3192
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3193<p>Because LLVM integers use a two's complement representation, this instruction
3194 is appropriate for both signed and unsigned integers.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3195
Dan Gohman902dfff2009-07-22 22:44:56 +0000[diff] [blame]3196<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3197 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3198 <tt>nsw</tt> keywords are present, the result value of the <tt>add</tt>
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]3199 is a <a href="#trapvalues">trap value</a> if unsigned and/or signed overflow,
3200 respectively, occurs.</p>
Dan Gohmanb07de442009-07-20 22:41:19 +0000[diff] [blame]3201
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3202<h5>Example:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3203<pre>
3204 &lt;result&gt; = add i32 4, %var <i>; yields {i32}:result = 4 + %var</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3205</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3206
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3207</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3208
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3209<!-- _______________________________________________________________________ -->
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3210<div class="doc_subsubsection">
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3211 <a name="i_fadd">'<tt>fadd</tt>' Instruction</a>
3212</div>
3213
3214<div class="doc_text">
3215
3216<h5>Syntax:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3217<pre>
3218 &lt;result&gt; = fadd &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3219</pre>
3220
3221<h5>Overview:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3222<p>The '<tt>fadd</tt>' instruction returns the sum of its two operands.</p>
3223
3224<h5>Arguments:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3225<p>The two arguments to the '<tt>fadd</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3226 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3227 floating point values. Both arguments must have identical types.</p>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3228
3229<h5>Semantics:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3230<p>The value produced is the floating point sum of the two operands.</p>
3231
3232<h5>Example:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3233<pre>
3234 &lt;result&gt; = fadd float 4.0, %var <i>; yields {float}:result = 4.0 + %var</i>
3235</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3236
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3237</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3238
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3239<!-- _______________________________________________________________________ -->
3240<div class="doc_subsubsection">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3241 <a name="i_sub">'<tt>sub</tt>' Instruction</a>
3242</div>
3243
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3244<div class="doc_text">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3245
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3246<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3247<pre>
Dan Gohman902dfff2009-07-22 22:44:56 +0000[diff] [blame]3248 &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]3249 &lt;result&gt; = sub nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3250 &lt;result&gt; = sub nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3251 &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]3252</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3253
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3254<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3255<p>The '<tt>sub</tt>' instruction returns the difference of its two
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3256 operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3257
3258<p>Note that the '<tt>sub</tt>' instruction is used to represent the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3259 '<tt>neg</tt>' instruction present in most other intermediate
3260 representations.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3261
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3262<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3263<p>The two arguments to the '<tt>sub</tt>' instruction must
3264 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3265 integer values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3266
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3267<h5>Semantics:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3268<p>The value produced is the integer difference of the two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3269
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3270<p>If the difference has unsigned overflow, the result returned is the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3271 mathematical result modulo 2<sup>n</sup>, where n is the bit width of the
3272 result.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3273
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3274<p>Because LLVM integers use a two's complement representation, this instruction
3275 is appropriate for both signed and unsigned integers.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3276
Dan Gohman902dfff2009-07-22 22:44:56 +0000[diff] [blame]3277<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3278 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3279 <tt>nsw</tt> keywords are present, the result value of the <tt>sub</tt>
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]3280 is a <a href="#trapvalues">trap value</a> if unsigned and/or signed overflow,
3281 respectively, occurs.</p>
Dan Gohmanb07de442009-07-20 22:41:19 +0000[diff] [blame]3282
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3283<h5>Example:</h5>
Bill Wendling2d8b9a82007-05-29 09:42:13 +0000[diff] [blame]3284<pre>
3285 &lt;result&gt; = sub i32 4, %var <i>; yields {i32}:result = 4 - %var</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3286 &lt;result&gt; = sub i32 0, %val <i>; yields {i32}:result = -%var</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3287</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3288
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3289</div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3290
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3291<!-- _______________________________________________________________________ -->
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3292<div class="doc_subsubsection">
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3293 <a name="i_fsub">'<tt>fsub</tt>' Instruction</a>
3294</div>
3295
3296<div class="doc_text">
3297
3298<h5>Syntax:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3299<pre>
3300 &lt;result&gt; = fsub &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3301</pre>
3302
3303<h5>Overview:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3304<p>The '<tt>fsub</tt>' instruction returns the difference of its two
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3305 operands.</p>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3306
3307<p>Note that the '<tt>fsub</tt>' instruction is used to represent the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3308 '<tt>fneg</tt>' instruction present in most other intermediate
3309 representations.</p>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3310
3311<h5>Arguments:</h5>
Bill Wendling972b7202009-07-20 02:32:41 +0000[diff] [blame]3312<p>The two arguments to the '<tt>fsub</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3313 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3314 floating point values. Both arguments must have identical types.</p>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3315
3316<h5>Semantics:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3317<p>The value produced is the floating point difference of the two operands.</p>
3318
3319<h5>Example:</h5>
3320<pre>
3321 &lt;result&gt; = fsub float 4.0, %var <i>; yields {float}:result = 4.0 - %var</i>
3322 &lt;result&gt; = fsub float -0.0, %val <i>; yields {float}:result = -%var</i>
3323</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3324
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3325</div>
3326
3327<!-- _______________________________________________________________________ -->
3328<div class="doc_subsubsection">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3329 <a name="i_mul">'<tt>mul</tt>' Instruction</a>
3330</div>
3331
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3332<div class="doc_text">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3333
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3334<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3335<pre>
Dan Gohman902dfff2009-07-22 22:44:56 +0000[diff] [blame]3336 &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]3337 &lt;result&gt; = mul nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3338 &lt;result&gt; = mul nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3339 &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]3340</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3341
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3342<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3343<p>The '<tt>mul</tt>' instruction returns the product of its two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3344
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3345<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3346<p>The two arguments to the '<tt>mul</tt>' instruction must
3347 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3348 integer values. Both arguments must have identical types.</p>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3349
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3350<h5>Semantics:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3351<p>The value produced is the integer product of the two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3352
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3353<p>If the result of the multiplication has unsigned overflow, the result
3354 returned is the mathematical result modulo 2<sup>n</sup>, where n is the bit
3355 width of the result.</p>
3356
3357<p>Because LLVM integers use a two's complement representation, and the result
3358 is the same width as the operands, this instruction returns the correct
3359 result for both signed and unsigned integers. If a full product
3360 (e.g. <tt>i32</tt>x<tt>i32</tt>-><tt>i64</tt>) is needed, the operands should
3361 be sign-extended or zero-extended as appropriate to the width of the full
3362 product.</p>
3363
Dan Gohman902dfff2009-07-22 22:44:56 +0000[diff] [blame]3364<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3365 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3366 <tt>nsw</tt> keywords are present, the result value of the <tt>mul</tt>
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]3367 is a <a href="#trapvalues">trap value</a> if unsigned and/or signed overflow,
3368 respectively, occurs.</p>
Dan Gohmanb07de442009-07-20 22:41:19 +0000[diff] [blame]3369
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3370<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3371<pre>
3372 &lt;result&gt; = mul i32 4, %var <i>; yields {i32}:result = 4 * %var</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3373</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3374
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3375</div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3376
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3377<!-- _______________________________________________________________________ -->
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3378<div class="doc_subsubsection">
3379 <a name="i_fmul">'<tt>fmul</tt>' Instruction</a>
3380</div>
3381
3382<div class="doc_text">
3383
3384<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3385<pre>
3386 &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]3387</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3388
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3389<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3390<p>The '<tt>fmul</tt>' instruction returns the product of its two operands.</p>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3391
3392<h5>Arguments:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3393<p>The two arguments to the '<tt>fmul</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3394 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3395 floating point values. Both arguments must have identical types.</p>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3396
3397<h5>Semantics:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3398<p>The value produced is the floating point product of the two operands.</p>
3399
3400<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3401<pre>
3402 &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]3403</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3404
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3405</div>
3406
3407<!-- _______________________________________________________________________ -->
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3408<div class="doc_subsubsection"> <a name="i_udiv">'<tt>udiv</tt>' Instruction
3409</a></div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3410
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3411<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3412
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3413<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3414<pre>
3415 &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]3416</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3417
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3418<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3419<p>The '<tt>udiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3420
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3421<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3422<p>The two arguments to the '<tt>udiv</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3423 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3424 values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3425
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3426<h5>Semantics:</h5>
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3427<p>The value produced is the unsigned integer quotient of the two operands.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3428
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3429<p>Note that unsigned integer division and signed integer division are distinct
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3430 operations; for signed integer division, use '<tt>sdiv</tt>'.</p>
3431
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3432<p>Division by zero leads to undefined behavior.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3433
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3434<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3435<pre>
3436 &lt;result&gt; = udiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3437</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3438
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3439</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3440
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3441<!-- _______________________________________________________________________ -->
3442<div class="doc_subsubsection"> <a name="i_sdiv">'<tt>sdiv</tt>' Instruction
3443</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3444
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3445<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3446
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3447<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3448<pre>
Dan Gohmanb07de442009-07-20 22:41:19 +0000[diff] [blame]3449 &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]3450 &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]3451</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3452
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3453<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3454<p>The '<tt>sdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3455
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3456<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3457<p>The two arguments to the '<tt>sdiv</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3458 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3459 values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3460
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3461<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3462<p>The value produced is the signed integer quotient of the two operands rounded
3463 towards zero.</p>
3464
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3465<p>Note that signed integer division and unsigned integer division are distinct
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3466 operations; for unsigned integer division, use '<tt>udiv</tt>'.</p>
3467
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3468<p>Division by zero leads to undefined behavior. Overflow also leads to
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3469 undefined behavior; this is a rare case, but can occur, for example, by doing
3470 a 32-bit division of -2147483648 by -1.</p>
3471
Dan Gohman71dfd782009-07-22 00:04:19 +0000[diff] [blame]3472<p>If the <tt>exact</tt> keyword is present, the result value of the
Dan Gohman57255802010-04-23 15:23:32 +0000[diff] [blame]3473 <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]3474 be rounded.</p>
Dan Gohmanb07de442009-07-20 22:41:19 +0000[diff] [blame]3475
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3476<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3477<pre>
3478 &lt;result&gt; = sdiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3479</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3480
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3481</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3482
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3483<!-- _______________________________________________________________________ -->
3484<div class="doc_subsubsection"> <a name="i_fdiv">'<tt>fdiv</tt>'
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3485Instruction</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3486
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3487<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3488
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3489<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3490<pre>
Gabor Greif0f75ad02008-08-07 21:46:00 +0000[diff] [blame]3491 &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]3492</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3493
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3494<h5>Overview:</h5>
3495<p>The '<tt>fdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3496
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3497<h5>Arguments:</h5>
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]3498<p>The two arguments to the '<tt>fdiv</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3499 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3500 floating point values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3501
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3502<h5>Semantics:</h5>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3503<p>The value produced is the floating point quotient of the two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3504
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3505<h5>Example:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3506<pre>
3507 &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]3508</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3509
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3510</div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3511
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3512<!-- _______________________________________________________________________ -->
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3513<div class="doc_subsubsection"> <a name="i_urem">'<tt>urem</tt>' Instruction</a>
3514</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3515
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3516<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3517
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3518<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3519<pre>
3520 &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]3521</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3522
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3523<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3524<p>The '<tt>urem</tt>' instruction returns the remainder from the unsigned
3525 division of its two arguments.</p>
3526
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3527<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3528<p>The two arguments to the '<tt>urem</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3529 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3530 values. Both arguments must have identical types.</p>
3531
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3532<h5>Semantics:</h5>
3533<p>This instruction returns the unsigned integer <i>remainder</i> of a division.
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3534 This instruction always performs an unsigned division to get the
3535 remainder.</p>
3536
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3537<p>Note that unsigned integer remainder and signed integer remainder are
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3538 distinct operations; for signed integer remainder, use '<tt>srem</tt>'.</p>
3539
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3540<p>Taking the remainder of a division by zero leads to undefined behavior.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3541
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3542<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3543<pre>
3544 &lt;result&gt; = urem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3545</pre>
3546
3547</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3548
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3549<!-- _______________________________________________________________________ -->
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3550<div class="doc_subsubsection">
3551 <a name="i_srem">'<tt>srem</tt>' Instruction</a>
3552</div>
3553
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3554<div class="doc_text">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3555
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3556<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3557<pre>
Gabor Greif0f75ad02008-08-07 21:46:00 +0000[diff] [blame]3558 &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]3559</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3560
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3561<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3562<p>The '<tt>srem</tt>' instruction returns the remainder from the signed
3563 division of its two operands. This instruction can also take
3564 <a href="#t_vector">vector</a> versions of the values in which case the
3565 elements must be integers.</p>
Chris Lattnerb8f816e2008-01-04 04:33:49 +0000[diff] [blame]3566
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3567<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3568<p>The two arguments to the '<tt>srem</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3569 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3570 values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3571
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3572<h5>Semantics:</h5>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3573<p>This instruction returns the <i>remainder</i> of a division (where the result
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3574 has the same sign as the dividend, <tt>op1</tt>), not the <i>modulo</i>
3575 operator (where the result has the same sign as the divisor, <tt>op2</tt>) of
3576 a value. For more information about the difference,
3577 see <a href="http://mathforum.org/dr.math/problems/anne.4.28.99.html">The
3578 Math Forum</a>. For a table of how this is implemented in various languages,
3579 please see <a href="http://en.wikipedia.org/wiki/Modulo_operation">
3580 Wikipedia: modulo operation</a>.</p>
3581
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3582<p>Note that signed integer remainder and unsigned integer remainder are
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3583 distinct operations; for unsigned integer remainder, use '<tt>urem</tt>'.</p>
3584
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3585<p>Taking the remainder of a division by zero leads to undefined behavior.
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3586 Overflow also leads to undefined behavior; this is a rare case, but can
3587 occur, for example, by taking the remainder of a 32-bit division of
3588 -2147483648 by -1. (The remainder doesn't actually overflow, but this rule
3589 lets srem be implemented using instructions that return both the result of
3590 the division and the remainder.)</p>
3591
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3592<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3593<pre>
3594 &lt;result&gt; = srem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3595</pre>
3596
3597</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3598
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3599<!-- _______________________________________________________________________ -->
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3600<div class="doc_subsubsection">
3601 <a name="i_frem">'<tt>frem</tt>' Instruction</a> </div>
3602
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3603<div class="doc_text">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3604
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3605<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3606<pre>
3607 &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]3608</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3609
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3610<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3611<p>The '<tt>frem</tt>' instruction returns the remainder from the division of
3612 its two operands.</p>
3613
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3614<h5>Arguments:</h5>
3615<p>The two arguments to the '<tt>frem</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3616 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3617 floating point values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3618
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3619<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3620<p>This instruction returns the <i>remainder</i> of a division. The remainder
3621 has the same sign as the dividend.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3622
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3623<h5>Example:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3624<pre>
3625 &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]3626</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3627
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3628</div>
Robert Bocchino820bc75b2006-02-17 21:18:08 +0000[diff] [blame]3629
Reid Spencer2ab01932007-02-02 13:57:07 +0000[diff] [blame]3630<!-- ======================================================================= -->
3631<div class="doc_subsection"> <a name="bitwiseops">Bitwise Binary
3632Operations</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3633
Reid Spencer2ab01932007-02-02 13:57:07 +0000[diff] [blame]3634<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3635
3636<p>Bitwise binary operators are used to do various forms of bit-twiddling in a
3637 program. They are generally very efficient instructions and can commonly be
3638 strength reduced from other instructions. They require two operands of the
3639 same type, execute an operation on them, and produce a single value. The
3640 resulting value is the same type as its operands.</p>
3641
Reid Spencer2ab01932007-02-02 13:57:07 +0000[diff] [blame]3642</div>
3643
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3644<!-- _______________________________________________________________________ -->
3645<div class="doc_subsubsection"> <a name="i_shl">'<tt>shl</tt>'
3646Instruction</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3647
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3648<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3649
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3650<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3651<pre>
3652 &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]3653</pre>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]3654
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3655<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3656<p>The '<tt>shl</tt>' instruction returns the first operand shifted to the left
3657 a specified number of bits.</p>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]3658
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3659<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3660<p>Both arguments to the '<tt>shl</tt>' instruction must be the
3661 same <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3662 integer type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3663
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3664<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3665<p>The value produced is <tt>op1</tt> * 2<sup><tt>op2</tt></sup> mod
3666 2<sup>n</sup>, where <tt>n</tt> is the width of the result. If <tt>op2</tt>
3667 is (statically or dynamically) negative or equal to or larger than the number
3668 of bits in <tt>op1</tt>, the result is undefined. If the arguments are
3669 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
3670 shift amount in <tt>op2</tt>.</p>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]3671
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3672<h5>Example:</h5>
3673<pre>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3674 &lt;result&gt; = shl i32 4, %var <i>; yields {i32}: 4 &lt;&lt; %var</i>
3675 &lt;result&gt; = shl i32 4, 2 <i>; yields {i32}: 16</i>
3676 &lt;result&gt; = shl i32 1, 10 <i>; yields {i32}: 1024</i>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]3677 &lt;result&gt; = shl i32 1, 32 <i>; undefined</i>
Mon P Wang4dd832d2008-12-09 05:46:39 +0000[diff] [blame]3678 &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]3679</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3680
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3681</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3682
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3683<!-- _______________________________________________________________________ -->
3684<div class="doc_subsubsection"> <a name="i_lshr">'<tt>lshr</tt>'
3685Instruction</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3686
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3687<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3688
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3689<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3690<pre>
3691 &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]3692</pre>
3693
3694<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3695<p>The '<tt>lshr</tt>' instruction (logical shift right) returns the first
3696 operand shifted to the right a specified number of bits with zero fill.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3697
3698<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3699<p>Both arguments to the '<tt>lshr</tt>' instruction must be the same
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3700 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3701 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3702
3703<h5>Semantics:</h5>
3704<p>This instruction always performs a logical shift right operation. The most
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3705 significant bits of the result will be filled with zero bits after the shift.
3706 If <tt>op2</tt> is (statically or dynamically) equal to or larger than the
3707 number of bits in <tt>op1</tt>, the result is undefined. If the arguments are
3708 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
3709 shift amount in <tt>op2</tt>.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3710
3711<h5>Example:</h5>
3712<pre>
3713 &lt;result&gt; = lshr i32 4, 1 <i>; yields {i32}:result = 2</i>
3714 &lt;result&gt; = lshr i32 4, 2 <i>; yields {i32}:result = 1</i>
3715 &lt;result&gt; = lshr i8 4, 3 <i>; yields {i8}:result = 0</i>
3716 &lt;result&gt; = lshr i8 -2, 1 <i>; yields {i8}:result = 0x7FFFFFFF </i>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]3717 &lt;result&gt; = lshr i32 1, 32 <i>; undefined</i>
Mon P Wang4dd832d2008-12-09 05:46:39 +0000[diff] [blame]3718 &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]3719</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3720
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3721</div>
3722
Reid Spencer2ab01932007-02-02 13:57:07 +0000[diff] [blame]3723<!-- _______________________________________________________________________ -->
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3724<div class="doc_subsubsection"> <a name="i_ashr">'<tt>ashr</tt>'
3725Instruction</a> </div>
3726<div class="doc_text">
3727
3728<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3729<pre>
3730 &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]3731</pre>
3732
3733<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3734<p>The '<tt>ashr</tt>' instruction (arithmetic shift right) returns the first
3735 operand shifted to the right a specified number of bits with sign
3736 extension.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3737
3738<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3739<p>Both arguments to the '<tt>ashr</tt>' instruction must be the same
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3740 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3741 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3742
3743<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3744<p>This instruction always performs an arithmetic shift right operation, The
3745 most significant bits of the result will be filled with the sign bit
3746 of <tt>op1</tt>. If <tt>op2</tt> is (statically or dynamically) equal to or
3747 larger than the number of bits in <tt>op1</tt>, the result is undefined. If
3748 the arguments are vectors, each vector element of <tt>op1</tt> is shifted by
3749 the corresponding shift amount in <tt>op2</tt>.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3750
3751<h5>Example:</h5>
3752<pre>
3753 &lt;result&gt; = ashr i32 4, 1 <i>; yields {i32}:result = 2</i>
3754 &lt;result&gt; = ashr i32 4, 2 <i>; yields {i32}:result = 1</i>
3755 &lt;result&gt; = ashr i8 4, 3 <i>; yields {i8}:result = 0</i>
3756 &lt;result&gt; = ashr i8 -2, 1 <i>; yields {i8}:result = -1</i>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]3757 &lt;result&gt; = ashr i32 1, 32 <i>; undefined</i>
Mon P Wang4dd832d2008-12-09 05:46:39 +0000[diff] [blame]3758 &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]3759</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3760
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3761</div>
3762
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3763<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3764<div class="doc_subsubsection"> <a name="i_and">'<tt>and</tt>'
3765Instruction</a> </div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3766
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3767<div class="doc_text">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3768
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3769<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3770<pre>
Gabor Greif0f75ad02008-08-07 21:46:00 +0000[diff] [blame]3771 &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]3772</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3773
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3774<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3775<p>The '<tt>and</tt>' instruction returns the bitwise logical and of its two
3776 operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3777
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3778<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3779<p>The two arguments to the '<tt>and</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3780 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3781 values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3782
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3783<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3784<p>The truth table used for the '<tt>and</tt>' instruction is:</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3785
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3786<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3787 <tbody>
3788 <tr>
3789 <td>In0</td>
3790 <td>In1</td>
3791 <td>Out</td>
3792 </tr>
3793 <tr>
3794 <td>0</td>
3795 <td>0</td>
3796 <td>0</td>
3797 </tr>
3798 <tr>
3799 <td>0</td>
3800 <td>1</td>
3801 <td>0</td>
3802 </tr>
3803 <tr>
3804 <td>1</td>
3805 <td>0</td>
3806 <td>0</td>
3807 </tr>
3808 <tr>
3809 <td>1</td>
3810 <td>1</td>
3811 <td>1</td>
3812 </tr>
3813 </tbody>
3814</table>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3815
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3816<h5>Example:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3817<pre>
3818 &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]3819 &lt;result&gt; = and i32 15, 40 <i>; yields {i32}:result = 8</i>
3820 &lt;result&gt; = and i32 4, 8 <i>; yields {i32}:result = 0</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3821</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3822</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3823<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3824<div class="doc_subsubsection"> <a name="i_or">'<tt>or</tt>' Instruction</a> </div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3825
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3826<div class="doc_text">
3827
3828<h5>Syntax:</h5>
3829<pre>
3830 &lt;result&gt; = or &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3831</pre>
3832
3833<h5>Overview:</h5>
3834<p>The '<tt>or</tt>' instruction returns the bitwise logical inclusive or of its
3835 two operands.</p>
3836
3837<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3838<p>The two arguments to the '<tt>or</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3839 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3840 values. Both arguments must have identical types.</p>
3841
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3842<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3843<p>The truth table used for the '<tt>or</tt>' instruction is:</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3844
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3845<table border="1" cellspacing="0" cellpadding="4">
3846 <tbody>
3847 <tr>
3848 <td>In0</td>
3849 <td>In1</td>
3850 <td>Out</td>
3851 </tr>
3852 <tr>
3853 <td>0</td>
3854 <td>0</td>
3855 <td>0</td>
3856 </tr>
3857 <tr>
3858 <td>0</td>
3859 <td>1</td>
3860 <td>1</td>
3861 </tr>
3862 <tr>
3863 <td>1</td>
3864 <td>0</td>
3865 <td>1</td>
3866 </tr>
3867 <tr>
3868 <td>1</td>
3869 <td>1</td>
3870 <td>1</td>
3871 </tr>
3872 </tbody>
3873</table>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3874
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3875<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3876<pre>
3877 &lt;result&gt; = or i32 4, %var <i>; yields {i32}:result = 4 | %var</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3878 &lt;result&gt; = or i32 15, 40 <i>; yields {i32}:result = 47</i>
3879 &lt;result&gt; = or i32 4, 8 <i>; yields {i32}:result = 12</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3880</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3881
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3882</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3883
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3884<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3885<div class="doc_subsubsection"> <a name="i_xor">'<tt>xor</tt>'
3886Instruction</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3887
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3888<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3889
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3890<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3891<pre>
3892 &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]3893</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3894
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3895<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3896<p>The '<tt>xor</tt>' instruction returns the bitwise logical exclusive or of
3897 its two operands. The <tt>xor</tt> is used to implement the "one's
3898 complement" operation, which is the "~" operator in C.</p>
3899
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3900<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3901<p>The two arguments to the '<tt>xor</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3902 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3903 values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3904
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3905<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3906<p>The truth table used for the '<tt>xor</tt>' instruction is:</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3907
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3908<table border="1" cellspacing="0" cellpadding="4">
3909 <tbody>
3910 <tr>
3911 <td>In0</td>
3912 <td>In1</td>
3913 <td>Out</td>
3914 </tr>
3915 <tr>
3916 <td>0</td>
3917 <td>0</td>
3918 <td>0</td>
3919 </tr>
3920 <tr>
3921 <td>0</td>
3922 <td>1</td>
3923 <td>1</td>
3924 </tr>
3925 <tr>
3926 <td>1</td>
3927 <td>0</td>
3928 <td>1</td>
3929 </tr>
3930 <tr>
3931 <td>1</td>
3932 <td>1</td>
3933 <td>0</td>
3934 </tr>
3935 </tbody>
3936</table>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3937
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3938<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3939<pre>
3940 &lt;result&gt; = xor i32 4, %var <i>; yields {i32}:result = 4 ^ %var</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3941 &lt;result&gt; = xor i32 15, 40 <i>; yields {i32}:result = 39</i>
3942 &lt;result&gt; = xor i32 4, 8 <i>; yields {i32}:result = 12</i>
3943 &lt;result&gt; = xor i32 %V, -1 <i>; yields {i32}:result = ~%V</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3944</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3945
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3946</div>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3947
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3948<!-- ======================================================================= -->
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3949<div class="doc_subsection">
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]3950 <a name="vectorops">Vector Operations</a>
3951</div>
3952
3953<div class="doc_text">
3954
3955<p>LLVM supports several instructions to represent vector operations in a
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3956 target-independent manner. These instructions cover the element-access and
3957 vector-specific operations needed to process vectors effectively. While LLVM
3958 does directly support these vector operations, many sophisticated algorithms
3959 will want to use target-specific intrinsics to take full advantage of a
3960 specific target.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]3961
3962</div>
3963
3964<!-- _______________________________________________________________________ -->
3965<div class="doc_subsubsection">
3966 <a name="i_extractelement">'<tt>extractelement</tt>' Instruction</a>
3967</div>
3968
3969<div class="doc_text">
3970
3971<h5>Syntax:</h5>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]3972<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3973 &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]3974</pre>
3975
3976<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3977<p>The '<tt>extractelement</tt>' instruction extracts a single scalar element
3978 from a vector at a specified index.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]3979
3980
3981<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3982<p>The first operand of an '<tt>extractelement</tt>' instruction is a value
3983 of <a href="#t_vector">vector</a> type. The second operand is an index
3984 indicating the position from which to extract the element. The index may be
3985 a variable.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]3986
3987<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3988<p>The result is a scalar of the same type as the element type of
3989 <tt>val</tt>. Its value is the value at position <tt>idx</tt> of
3990 <tt>val</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
3991 results are undefined.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]3992
3993<h5>Example:</h5>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]3994<pre>
Gabor Greif03ab4dc2009-10-28 13:14:50 +0000[diff] [blame]3995 &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]3996</pre>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]3997
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3998</div>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]3999
4000<!-- _______________________________________________________________________ -->
4001<div class="doc_subsubsection">
4002 <a name="i_insertelement">'<tt>insertelement</tt>' Instruction</a>
4003</div>
4004
4005<div class="doc_text">
4006
4007<h5>Syntax:</h5>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4008<pre>
Dan Gohman43ba0672008-05-12 23:38:42 +0000[diff] [blame]4009 &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]4010</pre>
4011
4012<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4013<p>The '<tt>insertelement</tt>' instruction inserts a scalar element into a
4014 vector at a specified index.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4015
4016<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4017<p>The first operand of an '<tt>insertelement</tt>' instruction is a value
4018 of <a href="#t_vector">vector</a> type. The second operand is a scalar value
4019 whose type must equal the element type of the first operand. The third
4020 operand is an index indicating the position at which to insert the value.
4021 The index may be a variable.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4022
4023<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4024<p>The result is a vector of the same type as <tt>val</tt>. Its element values
4025 are those of <tt>val</tt> except at position <tt>idx</tt>, where it gets the
4026 value <tt>elt</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
4027 results are undefined.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4028
4029<h5>Example:</h5>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4030<pre>
Gabor Greif03ab4dc2009-10-28 13:14:50 +0000[diff] [blame]4031 &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]4032</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4033
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4034</div>
4035
4036<!-- _______________________________________________________________________ -->
4037<div class="doc_subsubsection">
4038 <a name="i_shufflevector">'<tt>shufflevector</tt>' Instruction</a>
4039</div>
4040
4041<div class="doc_text">
4042
4043<h5>Syntax:</h5>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4044<pre>
Mon P Wang25f01062008-11-10 04:46:22 +0000[diff] [blame]4045 &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]4046</pre>
4047
4048<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4049<p>The '<tt>shufflevector</tt>' instruction constructs a permutation of elements
4050 from two input vectors, returning a vector with the same element type as the
4051 input and length that is the same as the shuffle mask.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4052
4053<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4054<p>The first two operands of a '<tt>shufflevector</tt>' instruction are vectors
4055 with types that match each other. The third argument is a shuffle mask whose
4056 element type is always 'i32'. The result of the instruction is a vector
4057 whose length is the same as the shuffle mask and whose element type is the
4058 same as the element type of the first two operands.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4059
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4060<p>The shuffle mask operand is required to be a constant vector with either
4061 constant integer or undef values.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4062
4063<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4064<p>The elements of the two input vectors are numbered from left to right across
4065 both of the vectors. The shuffle mask operand specifies, for each element of
4066 the result vector, which element of the two input vectors the result element
4067 gets. The element selector may be undef (meaning "don't care") and the
4068 second operand may be undef if performing a shuffle from only one vector.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4069
4070<h5>Example:</h5>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4071<pre>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4072 &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]4073 &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]4074 &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]4075 &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]4076 &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]4077 &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]4078 &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]4079 &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]4080</pre>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4081
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4082</div>
Tanya Lattnerb138bbe2006-04-14 19:24:33 +0000[diff] [blame]4083
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4084<!-- ======================================================================= -->
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4085<div class="doc_subsection">
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4086 <a name="aggregateops">Aggregate Operations</a>
4087</div>
4088
4089<div class="doc_text">
4090
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]4091<p>LLVM supports several instructions for working with
4092 <a href="#t_aggregate">aggregate</a> values.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4093
4094</div>
4095
4096<!-- _______________________________________________________________________ -->
4097<div class="doc_subsubsection">
4098 <a name="i_extractvalue">'<tt>extractvalue</tt>' Instruction</a>
4099</div>
4100
4101<div class="doc_text">
4102
4103<h5>Syntax:</h5>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4104<pre>
4105 &lt;result&gt; = extractvalue &lt;aggregate type&gt; &lt;val&gt;, &lt;idx&gt;{, &lt;idx&gt;}*
4106</pre>
4107
4108<h5>Overview:</h5>
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]4109<p>The '<tt>extractvalue</tt>' instruction extracts the value of a member field
4110 from an <a href="#t_aggregate">aggregate</a> value.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4111
4112<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4113<p>The first operand of an '<tt>extractvalue</tt>' instruction is a value
Chris Lattner13ee7952010-08-28 04:09:24 +0000[diff] [blame]4114 of <a href="#t_struct">struct</a> or
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]4115 <a href="#t_array">array</a> type. The operands are constant indices to
4116 specify which value to extract in a similar manner as indices in a
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4117 '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4118
4119<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4120<p>The result is the value at the position in the aggregate specified by the
4121 index operands.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4122
4123<h5>Example:</h5>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4124<pre>
Gabor Greif03ab4dc2009-10-28 13:14:50 +0000[diff] [blame]4125 &lt;result&gt; = extractvalue {i32, float} %agg, 0 <i>; yields i32</i>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4126</pre>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4127
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4128</div>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4129
4130<!-- _______________________________________________________________________ -->
4131<div class="doc_subsubsection">
4132 <a name="i_insertvalue">'<tt>insertvalue</tt>' Instruction</a>
4133</div>
4134
4135<div class="doc_text">
4136
4137<h5>Syntax:</h5>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4138<pre>
Jeffrey Yasskinf991bbb2010-01-11 19:19:26 +0000[diff] [blame]4139 &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]4140</pre>
4141
4142<h5>Overview:</h5>
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]4143<p>The '<tt>insertvalue</tt>' instruction inserts a value into a member field
4144 in an <a href="#t_aggregate">aggregate</a> value.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4145
4146<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4147<p>The first operand of an '<tt>insertvalue</tt>' instruction is a value
Chris Lattner13ee7952010-08-28 04:09:24 +0000[diff] [blame]4148 of <a href="#t_struct">struct</a> or
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]4149 <a href="#t_array">array</a> type. The second operand is a first-class
4150 value to insert. The following operands are constant indices indicating
4151 the position at which to insert the value in a similar manner as indices in a
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4152 '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction. The
4153 value to insert must have the same type as the value identified by the
4154 indices.</p>
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 an aggregate of the same type as <tt>val</tt>. Its value is
4158 that of <tt>val</tt> except that the value at the position specified by the
4159 indices is that of <tt>elt</tt>.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4160
4161<h5>Example:</h5>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4162<pre>
Jeffrey Yasskinf991bbb2010-01-11 19:19:26 +0000[diff] [blame]4163 %agg1 = insertvalue {i32, float} undef, i32 1, 0 <i>; yields {i32 1, float undef}</i>
4164 %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]4165</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4166
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4167</div>
4168
4169
4170<!-- ======================================================================= -->
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4171<div class="doc_subsection">
Chris Lattner6ab66722006-08-15 00:45:58 +0000[diff] [blame]4172 <a name="memoryops">Memory Access and Addressing Operations</a>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4173</div>
4174
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4175<div class="doc_text">
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4176
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4177<p>A key design point of an SSA-based representation is how it represents
4178 memory. In LLVM, no memory locations are in SSA form, which makes things
Victor Hernandeza70c6df2009-10-26 23:44:29 +0000[diff] [blame]4179 very simple. This section describes how to read, write, and allocate
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4180 memory in LLVM.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4181
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4182</div>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4183
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4184<!-- _______________________________________________________________________ -->
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4185<div class="doc_subsubsection">
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4186 <a name="i_alloca">'<tt>alloca</tt>' Instruction</a>
4187</div>
4188
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4189<div class="doc_text">
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4190
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4191<h5>Syntax:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4192<pre>
Dan Gohman2140a742010-05-28 01:14:11 +0000[diff] [blame]4193 &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]4194</pre>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4195
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4196<h5>Overview:</h5>
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]4197<p>The '<tt>alloca</tt>' instruction allocates memory on the stack frame of the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4198 currently executing function, to be automatically released when this function
4199 returns to its caller. The object is always allocated in the generic address
4200 space (address space zero).</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4201
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4202<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4203<p>The '<tt>alloca</tt>' instruction
4204 allocates <tt>sizeof(&lt;type&gt;)*NumElements</tt> bytes of memory on the
4205 runtime stack, returning a pointer of the appropriate type to the program.
4206 If "NumElements" is specified, it is the number of elements allocated,
4207 otherwise "NumElements" is defaulted to be one. If a constant alignment is
4208 specified, the value result of the allocation is guaranteed to be aligned to
4209 at least that boundary. If not specified, or if zero, the target can choose
4210 to align the allocation on any convenient boundary compatible with the
4211 type.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4212
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4213<p>'<tt>type</tt>' may be any sized type.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4214
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4215<h5>Semantics:</h5>
Bill Wendling9ee6a312009-05-08 20:49:29 +0000[diff] [blame]4216<p>Memory is allocated; a pointer is returned. The operation is undefined if
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4217 there is insufficient stack space for the allocation. '<tt>alloca</tt>'d
4218 memory is automatically released when the function returns. The
4219 '<tt>alloca</tt>' instruction is commonly used to represent automatic
4220 variables that must have an address available. When the function returns
4221 (either with the <tt><a href="#i_ret">ret</a></tt>
4222 or <tt><a href="#i_unwind">unwind</a></tt> instructions), the memory is
4223 reclaimed. Allocating zero bytes is legal, but the result is undefined.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4224
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4225<h5>Example:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4226<pre>
Dan Gohman7a5acb52009-01-04 23:49:44 +0000[diff] [blame]4227 %ptr = alloca i32 <i>; yields {i32*}:ptr</i>
4228 %ptr = alloca i32, i32 4 <i>; yields {i32*}:ptr</i>
4229 %ptr = alloca i32, i32 4, align 1024 <i>; yields {i32*}:ptr</i>
4230 %ptr = alloca i32, align 1024 <i>; yields {i32*}:ptr</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4231</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4232
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4233</div>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4234
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4235<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]4236<div class="doc_subsubsection"> <a name="i_load">'<tt>load</tt>'
4237Instruction</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4238
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4239<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4240
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4241<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4242<pre>
Bill Wendlingbc4024f2010-02-25 21:23:24 +0000[diff] [blame]4243 &lt;result&gt; = load &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;][, !nontemporal !&lt;index&gt;]
4244 &lt;result&gt; = volatile load &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;][, !nontemporal !&lt;index&gt;]
4245 !&lt;index&gt; = !{ i32 1 }
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4246</pre>
4247
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4248<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4249<p>The '<tt>load</tt>' instruction is used to read from memory.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4250
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4251<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4252<p>The argument to the '<tt>load</tt>' instruction specifies the memory address
4253 from which to load. The pointer must point to
4254 a <a href="#t_firstclass">first class</a> type. If the <tt>load</tt> is
4255 marked as <tt>volatile</tt>, then the optimizer is not allowed to modify the
Jeffrey Yasskin5d284ae2010-04-26 21:21:24 +0000[diff] [blame]4256 number or order of execution of this <tt>load</tt> with other <a
4257 href="#volatile">volatile operations</a>.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4258
Bill Wendlingbc4024f2010-02-25 21:23:24 +0000[diff] [blame]4259<p>The optional constant <tt>align</tt> argument specifies the alignment of the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4260 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]4261 omitted <tt>align</tt> argument means that the operation has the preferential
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4262 alignment for the target. It is the responsibility of the code emitter to
4263 ensure that the alignment information is correct. Overestimating the
Bill Wendlingbc4024f2010-02-25 21:23:24 +0000[diff] [blame]4264 alignment results in undefined behavior. Underestimating the alignment may
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4265 produce less efficient code. An alignment of 1 is always safe.</p>
4266
Bill Wendlingbc4024f2010-02-25 21:23:24 +0000[diff] [blame]4267<p>The optional <tt>!nontemporal</tt> metadata must reference a single
4268 metatadata name &lt;index&gt; corresponding to a metadata node with
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]4269 one <tt>i32</tt> entry of value 1. The existence of
Bill Wendlingbc4024f2010-02-25 21:23:24 +0000[diff] [blame]4270 the <tt>!nontemporal</tt> metatadata on the instruction tells the optimizer
4271 and code generator that this load is not expected to be reused in the cache.
4272 The code generator may select special instructions to save cache bandwidth,
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]4273 such as the <tt>MOVNT</tt> instruction on x86.</p>
David Greene9641d062010-02-16 20:50:18 +0000[diff] [blame]4274
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4275<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4276<p>The location of memory pointed to is loaded. If the value being loaded is of
4277 scalar type then the number of bytes read does not exceed the minimum number
4278 of bytes needed to hold all bits of the type. For example, loading an
4279 <tt>i24</tt> reads at most three bytes. When loading a value of a type like
4280 <tt>i20</tt> with a size that is not an integral number of bytes, the result
4281 is undefined if the value was not originally written using a store of the
4282 same type.</p>
4283
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4284<h5>Examples:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4285<pre>
4286 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
4287 <a href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4288 %val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4289</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4290
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4291</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4292
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4293<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]4294<div class="doc_subsubsection"> <a name="i_store">'<tt>store</tt>'
4295Instruction</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4296
Reid Spencera89fb182006-11-09 21:18:01 +0000[diff] [blame]4297<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4298
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4299<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4300<pre>
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]4301 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>
4302 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]4303</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4304
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4305<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4306<p>The '<tt>store</tt>' instruction is used to write to memory.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4307
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4308<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4309<p>There are two arguments to the '<tt>store</tt>' instruction: a value to store
4310 and an address at which to store it. The type of the
4311 '<tt>&lt;pointer&gt;</tt>' operand must be a pointer to
4312 the <a href="#t_firstclass">first class</a> type of the
Jeffrey Yasskin5d284ae2010-04-26 21:21:24 +0000[diff] [blame]4313 '<tt>&lt;value&gt;</tt>' operand. If the <tt>store</tt> is marked as
4314 <tt>volatile</tt>, then the optimizer is not allowed to modify the number or
4315 order of execution of this <tt>store</tt> with other <a
4316 href="#volatile">volatile operations</a>.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4317
4318<p>The optional constant "align" argument specifies the alignment of the
4319 operation (that is, the alignment of the memory address). A value of 0 or an
4320 omitted "align" argument means that the operation has the preferential
4321 alignment for the target. It is the responsibility of the code emitter to
4322 ensure that the alignment information is correct. Overestimating the
4323 alignment results in an undefined behavior. Underestimating the alignment may
4324 produce less efficient code. An alignment of 1 is always safe.</p>
4325
David Greene9641d062010-02-16 20:50:18 +0000[diff] [blame]4326<p>The optional !nontemporal metadata must reference a single metatadata
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]4327 name &lt;index&gt; corresponding to a metadata node with one i32 entry of
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]4328 value 1. The existence of the !nontemporal metatadata on the
David Greene9641d062010-02-16 20:50:18 +0000[diff] [blame]4329 instruction tells the optimizer and code generator that this load is
4330 not expected to be reused in the cache. The code generator may
4331 select special instructions to save cache bandwidth, such as the
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]4332 MOVNT instruction on x86.</p>
David Greene9641d062010-02-16 20:50:18 +0000[diff] [blame]4333
4334
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]4335<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4336<p>The contents of memory are updated to contain '<tt>&lt;value&gt;</tt>' at the
4337 location specified by the '<tt>&lt;pointer&gt;</tt>' operand. If
4338 '<tt>&lt;value&gt;</tt>' is of scalar type then the number of bytes written
4339 does not exceed the minimum number of bytes needed to hold all bits of the
4340 type. For example, storing an <tt>i24</tt> writes at most three bytes. When
4341 writing a value of a type like <tt>i20</tt> with a size that is not an
4342 integral number of bytes, it is unspecified what happens to the extra bits
4343 that do not belong to the type, but they will typically be overwritten.</p>
4344
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4345<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4346<pre>
4347 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Bill Wendling8830ffe2007-10-22 05:10:05 +0000[diff] [blame]4348 store i32 3, i32* %ptr <i>; yields {void}</i>
4349 %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]4350</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4351
Reid Spencer443460a2006-11-09 21:15:49 +0000[diff] [blame]4352</div>
4353
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4354<!-- _______________________________________________________________________ -->
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4355<div class="doc_subsubsection">
4356 <a name="i_getelementptr">'<tt>getelementptr</tt>' Instruction</a>
4357</div>
4358
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4359<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4360
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]4361<h5>Syntax:</h5>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4362<pre>
Matthijs Kooijman0e268272008-10-13 13:44:15 +0000[diff] [blame]4363 &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]4364 &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]4365</pre>
4366
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]4367<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4368<p>The '<tt>getelementptr</tt>' instruction is used to get the address of a
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]4369 subelement of an <a href="#t_aggregate">aggregate</a> data structure.
4370 It performs address calculation only and does not access memory.</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4371
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]4372<h5>Arguments:</h5>
Matthijs Kooijman0e268272008-10-13 13:44:15 +0000[diff] [blame]4373<p>The first argument is always a pointer, and forms the basis of the
Chris Lattnera40b9122009-07-29 06:44:13 +0000[diff] [blame]4374 calculation. The remaining arguments are indices that indicate which of the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4375 elements of the aggregate object are indexed. The interpretation of each
4376 index is dependent on the type being indexed into. The first index always
4377 indexes the pointer value given as the first argument, the second index
4378 indexes a value of the type pointed to (not necessarily the value directly
4379 pointed to, since the first index can be non-zero), etc. The first type
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]4380 indexed into must be a pointer value, subsequent types can be arrays,
Chris Lattner13ee7952010-08-28 04:09:24 +0000[diff] [blame]4381 vectors, and structs. Note that subsequent types being indexed into
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]4382 can never be pointers, since that would require loading the pointer before
4383 continuing calculation.</p>
Matthijs Kooijman0e268272008-10-13 13:44:15 +0000[diff] [blame]4384
4385<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]4386 When indexing into a (optionally packed) structure, only <tt>i32</tt>
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]4387 integer <b>constants</b> are allowed. When indexing into an array, pointer
4388 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]4389 constant.</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4390
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4391<p>For example, let's consider a C code fragment and how it gets compiled to
4392 LLVM:</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4393
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]4394<pre class="doc_code">
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]4395struct RT {
4396 char A;
Chris Lattnera446f1b2007-05-29 15:43:56 +0000[diff] [blame]4397 int B[10][20];
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]4398 char C;
4399};
4400struct ST {
Chris Lattnera446f1b2007-05-29 15:43:56 +0000[diff] [blame]4401 int X;
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]4402 double Y;
4403 struct RT Z;
4404};
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4405
Chris Lattnera446f1b2007-05-29 15:43:56 +0000[diff] [blame]4406int *foo(struct ST *s) {
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]4407 return &amp;s[1].Z.B[5][13];
4408}
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4409</pre>
4410
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4411<p>The LLVM code generated by the GCC frontend is:</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4412
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]4413<pre class="doc_code">
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]4414%RT = <a href="#namedtypes">type</a> { i8 , [10 x [20 x i32]], i8 }
4415%ST = <a href="#namedtypes">type</a> { i32, double, %RT }
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4416
Dan Gohman6b867702009-07-25 02:23:48 +0000[diff] [blame]4417define i32* @foo(%ST* %s) {
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]4418entry:
4419 %reg = getelementptr %ST* %s, i32 1, i32 2, i32 1, i32 5, i32 13
4420 ret i32* %reg
4421}
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4422</pre>
4423
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]4424<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4425<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]4426 type, which is a pointer, yielding a '<tt>%ST</tt>' = '<tt>{ i32, double, %RT
4427 }</tt>' type, a structure. The second index indexes into the third element
4428 of the structure, yielding a '<tt>%RT</tt>' = '<tt>{ i8 , [10 x [20 x i32]],
4429 i8 }</tt>' type, another structure. The third index indexes into the second
4430 element of the structure, yielding a '<tt>[10 x [20 x i32]]</tt>' type, an
4431 array. The two dimensions of the array are subscripted into, yielding an
4432 '<tt>i32</tt>' type. The '<tt>getelementptr</tt>' instruction returns a
4433 pointer to this element, thus computing a value of '<tt>i32*</tt>' type.</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4434
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4435<p>Note that it is perfectly legal to index partially through a structure,
4436 returning a pointer to an inner element. Because of this, the LLVM code for
4437 the given testcase is equivalent to:</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4438
4439<pre>
Dan Gohman6b867702009-07-25 02:23:48 +0000[diff] [blame]4440 define i32* @foo(%ST* %s) {
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4441 %t1 = getelementptr %ST* %s, i32 1 <i>; yields %ST*:%t1</i>
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]4442 %t2 = getelementptr %ST* %t1, i32 0, i32 2 <i>; yields %RT*:%t2</i>
4443 %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]4444 %t4 = getelementptr [10 x [20 x i32]]* %t3, i32 0, i32 5 <i>; yields [20 x i32]*:%t4</i>
4445 %t5 = getelementptr [20 x i32]* %t4, i32 0, i32 13 <i>; yields i32*:%t5</i>
4446 ret i32* %t5
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4447 }
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]4448</pre>
Chris Lattnerc0ad71e2005-06-24 17:22:57 +0000[diff] [blame]4449
Dan Gohman1639c392009-07-27 21:53:46 +0000[diff] [blame]4450<p>If the <tt>inbounds</tt> keyword is present, the result value of the
Dan Gohman57255802010-04-23 15:23:32 +0000[diff] [blame]4451 <tt>getelementptr</tt> is a <a href="#trapvalues">trap value</a> if the
4452 base pointer is not an <i>in bounds</i> address of an allocated object,
4453 or if any of the addresses that would be formed by successive addition of
4454 the offsets implied by the indices to the base address with infinitely
4455 precise arithmetic are not an <i>in bounds</i> address of that allocated
4456 object. The <i>in bounds</i> addresses for an allocated object are all
4457 the addresses that point into the object, plus the address one byte past
4458 the end.</p>
Dan Gohman1639c392009-07-27 21:53:46 +0000[diff] [blame]4459
4460<p>If the <tt>inbounds</tt> keyword is not present, the offsets are added to
4461 the base address with silently-wrapping two's complement arithmetic, and
4462 the result value of the <tt>getelementptr</tt> may be outside the object
4463 pointed to by the base pointer. The result value may not necessarily be
4464 used to access memory though, even if it happens to point into allocated
4465 storage. See the <a href="#pointeraliasing">Pointer Aliasing Rules</a>
4466 section for more information.</p>
4467
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4468<p>The getelementptr instruction is often confusing. For some more insight into
4469 how it works, see <a href="GetElementPtr.html">the getelementptr FAQ</a>.</p>
Chris Lattner6ab66722006-08-15 00:45:58 +0000[diff] [blame]4470
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]4471<h5>Example:</h5>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4472<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4473 <i>; yields [12 x i8]*:aptr</i>
Matthijs Kooijman0e268272008-10-13 13:44:15 +0000[diff] [blame]4474 %aptr = getelementptr {i32, [12 x i8]}* %saptr, i64 0, i32 1
4475 <i>; yields i8*:vptr</i>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]4476 %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]4477 <i>; yields i8*:eptr</i>
4478 %eptr = getelementptr [12 x i8]* %aptr, i64 0, i32 1
Sanjiv Gupta0c155e62009-04-25 07:27:44 +0000[diff] [blame]4479 <i>; yields i32*:iptr</i>
Sanjiv Gupta77abea02009-04-24 16:38:13 +0000[diff] [blame]4480 %iptr = getelementptr [10 x i32]* @arr, i16 0, i16 0
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4481</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4482
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4483</div>
Reid Spencer443460a2006-11-09 21:15:49 +0000[diff] [blame]4484
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4485<!-- ======================================================================= -->
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]4486<div class="doc_subsection"> <a name="convertops">Conversion Operations</a>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4487</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4488
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4489<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4490
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]4491<p>The instructions in this category are the conversion instructions (casting)
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4492 which all take a single operand and a type. They perform various bit
4493 conversions on the operand.</p>
4494
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4495</div>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]4496
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]4497<!-- _______________________________________________________________________ -->
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]4498<div class="doc_subsubsection">
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4499 <a name="i_trunc">'<tt>trunc .. to</tt>' Instruction</a>
4500</div>
4501<div class="doc_text">
4502
4503<h5>Syntax:</h5>
4504<pre>
4505 &lt;result&gt; = trunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4506</pre>
4507
4508<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4509<p>The '<tt>trunc</tt>' instruction truncates its operand to the
4510 type <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4511
4512<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4513<p>The '<tt>trunc</tt>' instruction takes a <tt>value</tt> to trunc, which must
4514 be an <a href="#t_integer">integer</a> type, and a type that specifies the
4515 size and type of the result, which must be
4516 an <a href="#t_integer">integer</a> type. The bit size of <tt>value</tt> must
4517 be larger than the bit size of <tt>ty2</tt>. Equal sized types are not
4518 allowed.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4519
4520<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4521<p>The '<tt>trunc</tt>' instruction truncates the high order bits
4522 in <tt>value</tt> and converts the remaining bits to <tt>ty2</tt>. Since the
4523 source size must be larger than the destination size, <tt>trunc</tt> cannot
4524 be a <i>no-op cast</i>. It will always truncate bits.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4525
4526<h5>Example:</h5>
4527<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4528 %X = trunc i32 257 to i8 <i>; yields i8:1</i>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]4529 %Y = trunc i32 123 to i1 <i>; yields i1:true</i>
Gabor Greiff50fd572009-10-28 09:21:30 +0000[diff] [blame]4530 %Z = trunc i32 122 to i1 <i>; yields i1:false</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4531</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4532
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4533</div>
4534
4535<!-- _______________________________________________________________________ -->
4536<div class="doc_subsubsection">
4537 <a name="i_zext">'<tt>zext .. to</tt>' Instruction</a>
4538</div>
4539<div class="doc_text">
4540
4541<h5>Syntax:</h5>
4542<pre>
4543 &lt;result&gt; = zext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4544</pre>
4545
4546<h5>Overview:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4547<p>The '<tt>zext</tt>' instruction zero extends its operand to type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4548 <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4549
4550
4551<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4552<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]4553 <a href="#t_integer">integer</a> type, and a type to cast it to, which must
4554 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]4555 <tt>value</tt> must be smaller than the bit size of the destination type,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4556 <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4557
4558<h5>Semantics:</h5>
4559<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]4560 bits until it reaches the size of the destination type, <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4561
Reid Spencer07c9c682007-01-12 15:46:11 +0000[diff] [blame]4562<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]4563
4564<h5>Example:</h5>
4565<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4566 %X = zext i32 257 to i64 <i>; yields i64:257</i>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]4567 %Y = zext i1 true to i32 <i>; yields i32:1</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_sext">'<tt>sext .. to</tt>' Instruction</a>
4575</div>
4576<div class="doc_text">
4577
4578<h5>Syntax:</h5>
4579<pre>
4580 &lt;result&gt; = sext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4581</pre>
4582
4583<h5>Overview:</h5>
4584<p>The '<tt>sext</tt>' sign extends <tt>value</tt> to the type <tt>ty2</tt>.</p>
4585
4586<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4587<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]4588 <a href="#t_integer">integer</a> type, and a type to cast it to, which must
4589 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]4590 <tt>value</tt> must be smaller than the bit size of the destination type,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4591 <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4592
4593<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4594<p>The '<tt>sext</tt>' instruction performs a sign extension by copying the sign
4595 bit (highest order bit) of the <tt>value</tt> until it reaches the bit size
4596 of the type <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4597
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]4598<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]4599
4600<h5>Example:</h5>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4601<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4602 %X = sext i8 -1 to i16 <i>; yields i16 :65535</i>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]4603 %Y = sext i1 true to i32 <i>; yields i32:-1</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4604</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4605
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4606</div>
4607
4608<!-- _______________________________________________________________________ -->
4609<div class="doc_subsubsection">
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]4610 <a name="i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a>
4611</div>
4612
4613<div class="doc_text">
4614
4615<h5>Syntax:</h5>
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]4616<pre>
4617 &lt;result&gt; = fptrunc &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>fptrunc</tt>' instruction truncates <tt>value</tt> to type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4622 <tt>ty2</tt>.</p>
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]4623
4624<h5>Arguments:</h5>
4625<p>The '<tt>fptrunc</tt>' instruction takes a <a href="#t_floating">floating
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4626 point</a> value to cast and a <a href="#t_floating">floating point</a> type
4627 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]4628 <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]4629 <i>no-op cast</i>.</p>
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]4630
4631<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4632<p>The '<tt>fptrunc</tt>' instruction truncates a <tt>value</tt> from a larger
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4633 <a href="#t_floating">floating point</a> type to a smaller
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4634 <a href="#t_floating">floating point</a> type. If the value cannot fit
4635 within the destination type, <tt>ty2</tt>, then the results are
4636 undefined.</p>
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]4637
4638<h5>Example:</h5>
4639<pre>
4640 %X = fptrunc double 123.0 to float <i>; yields float:123.0</i>
4641 %Y = fptrunc double 1.0E+300 to float <i>; yields undefined</i>
4642</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4643
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]4644</div>
4645
4646<!-- _______________________________________________________________________ -->
4647<div class="doc_subsubsection">
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4648 <a name="i_fpext">'<tt>fpext .. to</tt>' Instruction</a>
4649</div>
4650<div class="doc_text">
4651
4652<h5>Syntax:</h5>
4653<pre>
4654 &lt;result&gt; = fpext &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>fpext</tt>' extends a floating point <tt>value</tt> to a larger
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4659 floating point value.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4660
4661<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4662<p>The '<tt>fpext</tt>' instruction takes a
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4663 <a href="#t_floating">floating point</a> <tt>value</tt> to cast, and
4664 a <a href="#t_floating">floating point</a> type to cast it to. The source
4665 type must be smaller than the destination type.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4666
4667<h5>Semantics:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]4668<p>The '<tt>fpext</tt>' instruction extends the <tt>value</tt> from a smaller
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4669 <a href="#t_floating">floating point</a> type to a larger
4670 <a href="#t_floating">floating point</a> type. The <tt>fpext</tt> cannot be
4671 used to make a <i>no-op cast</i> because it always changes bits. Use
4672 <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]4673
4674<h5>Example:</h5>
4675<pre>
4676 %X = fpext float 3.1415 to double <i>; yields double:3.1415</i>
4677 %Y = fpext float 1.0 to float <i>; yields float:1.0 (no-op)</i>
4678</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4679
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4680</div>
4681
4682<!-- _______________________________________________________________________ -->
4683<div class="doc_subsubsection">
Reid Spencer2eadb532007-01-21 00:29:26 +0000[diff] [blame]4684 <a name="i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4685</div>
4686<div class="doc_text">
4687
4688<h5>Syntax:</h5>
4689<pre>
Reid Spencer753163d2007-07-31 14:40:14 +0000[diff] [blame]4690 &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]4691</pre>
4692
4693<h5>Overview:</h5>
Reid Spencer753163d2007-07-31 14:40:14 +0000[diff] [blame]4694<p>The '<tt>fptoui</tt>' converts a floating point <tt>value</tt> to its
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4695 unsigned integer equivalent of type <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4696
4697<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4698<p>The '<tt>fptoui</tt>' instruction takes a value to cast, which must be a
4699 scalar or vector <a href="#t_floating">floating point</a> value, and a type
4700 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
4701 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
4702 vector integer type with the same number of elements as <tt>ty</tt></p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4703
4704<h5>Semantics:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4705<p>The '<tt>fptoui</tt>' instruction converts its
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4706 <a href="#t_floating">floating point</a> operand into the nearest (rounding
4707 towards zero) unsigned integer value. If the value cannot fit
4708 in <tt>ty2</tt>, the results are undefined.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4709
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4710<h5>Example:</h5>
4711<pre>
Reid Spencer753163d2007-07-31 14:40:14 +0000[diff] [blame]4712 %X = fptoui double 123.0 to i32 <i>; yields i32:123</i>
Chris Lattner5b95a172007-09-22 03:17:52 +0000[diff] [blame]4713 %Y = fptoui float 1.0E+300 to i1 <i>; yields undefined:1</i>
Gabor Greiff50fd572009-10-28 09:21:30 +0000[diff] [blame]4714 %Z = fptoui float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]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 Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]4721 <a name="i_fptosi">'<tt>fptosi .. 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 Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]4727 &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]4728</pre>
4729
4730<h5>Overview:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4731<p>The '<tt>fptosi</tt>' instruction converts
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4732 <a href="#t_floating">floating point</a> <tt>value</tt> to
4733 type <tt>ty2</tt>.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]4734
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]4735<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4736<p>The '<tt>fptosi</tt>' instruction takes a value to cast, which must be a
4737 scalar or vector <a href="#t_floating">floating point</a> value, and a type
4738 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
4739 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
4740 vector integer type with the same number of elements as <tt>ty</tt></p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]4741
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]4742<h5>Semantics:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4743<p>The '<tt>fptosi</tt>' instruction converts its
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4744 <a href="#t_floating">floating point</a> operand into the nearest (rounding
4745 towards zero) signed integer value. If the value cannot fit in <tt>ty2</tt>,
4746 the results are undefined.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]4747
Chris Lattner70de6632001-07-09 00:26:23 +0000[diff] [blame]4748<h5>Example:</h5>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]4749<pre>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]4750 %X = fptosi double -123.0 to i32 <i>; yields i32:-123</i>
Chris Lattner5b95a172007-09-22 03:17:52 +0000[diff] [blame]4751 %Y = fptosi float 1.0E-247 to i1 <i>; yields undefined:1</i>
Gabor Greiff50fd572009-10-28 09:21:30 +0000[diff] [blame]4752 %Z = fptosi float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4753</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4754
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4755</div>
4756
4757<!-- _______________________________________________________________________ -->
4758<div class="doc_subsubsection">
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]4759 <a name="i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4760</div>
4761<div class="doc_text">
4762
4763<h5>Syntax:</h5>
4764<pre>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]4765 &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]4766</pre>
4767
4768<h5>Overview:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]4769<p>The '<tt>uitofp</tt>' instruction regards <tt>value</tt> as an unsigned
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4770 integer and converts that value to the <tt>ty2</tt> type.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4771
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4772<h5>Arguments:</h5>
Nate Begemand4d45c22007-11-17 03:58:34 +0000[diff] [blame]4773<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]4774 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
4775 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
4776 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
4777 floating point type with the same number of elements as <tt>ty</tt></p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4778
4779<h5>Semantics:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]4780<p>The '<tt>uitofp</tt>' instruction interprets its operand as an unsigned
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4781 integer quantity and converts it to the corresponding floating point
4782 value. If the value cannot fit in the floating point value, the results are
4783 undefined.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4784
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4785<h5>Example:</h5>
4786<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4787 %X = uitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]4788 %Y = uitofp i8 -1 to double <i>; yields double:255.0</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4789</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4790
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4791</div>
4792
4793<!-- _______________________________________________________________________ -->
4794<div class="doc_subsubsection">
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]4795 <a name="i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4796</div>
4797<div class="doc_text">
4798
4799<h5>Syntax:</h5>
4800<pre>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]4801 &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]4802</pre>
4803
4804<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4805<p>The '<tt>sitofp</tt>' instruction regards <tt>value</tt> as a signed integer
4806 and converts that value to the <tt>ty2</tt> type.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4807
4808<h5>Arguments:</h5>
Nate Begemand4d45c22007-11-17 03:58:34 +0000[diff] [blame]4809<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]4810 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
4811 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
4812 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
4813 floating point type with the same number of elements as <tt>ty</tt></p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4814
4815<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4816<p>The '<tt>sitofp</tt>' instruction interprets its operand as a signed integer
4817 quantity and converts it to the corresponding floating point value. If the
4818 value cannot fit in the floating point value, the results are undefined.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4819
4820<h5>Example:</h5>
4821<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4822 %X = sitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]4823 %Y = sitofp i8 -1 to double <i>; yields double:-1.0</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4824</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4825
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4826</div>
4827
4828<!-- _______________________________________________________________________ -->
4829<div class="doc_subsubsection">
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]4830 <a name="i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a>
4831</div>
4832<div class="doc_text">
4833
4834<h5>Syntax:</h5>
4835<pre>
4836 &lt;result&gt; = ptrtoint &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4837</pre>
4838
4839<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4840<p>The '<tt>ptrtoint</tt>' instruction converts the pointer <tt>value</tt> to
4841 the integer type <tt>ty2</tt>.</p>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]4842
4843<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4844<p>The '<tt>ptrtoint</tt>' instruction takes a <tt>value</tt> to cast, which
4845 must be a <a href="#t_pointer">pointer</a> value, and a type to cast it to
4846 <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]4847
4848<h5>Semantics:</h5>
4849<p>The '<tt>ptrtoint</tt>' instruction converts <tt>value</tt> to integer type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4850 <tt>ty2</tt> by interpreting the pointer value as an integer and either
4851 truncating or zero extending that value to the size of the integer type. If
4852 <tt>value</tt> is smaller than <tt>ty2</tt> then a zero extension is done. If
4853 <tt>value</tt> is larger than <tt>ty2</tt> then a truncation is done. If they
4854 are the same size, then nothing is done (<i>no-op cast</i>) other than a type
4855 change.</p>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]4856
4857<h5>Example:</h5>
4858<pre>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]4859 %X = ptrtoint i32* %X to i8 <i>; yields truncation on 32-bit architecture</i>
4860 %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]4861</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4862
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]4863</div>
4864
4865<!-- _______________________________________________________________________ -->
4866<div class="doc_subsubsection">
4867 <a name="i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a>
4868</div>
4869<div class="doc_text">
4870
4871<h5>Syntax:</h5>
4872<pre>
4873 &lt;result&gt; = inttoptr &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>inttoptr</tt>' instruction converts an integer <tt>value</tt> to a
4878 pointer type, <tt>ty2</tt>.</p>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]4879
4880<h5>Arguments:</h5>
Duncan Sands16f122e2007-03-30 12:22:09 +0000[diff] [blame]4881<p>The '<tt>inttoptr</tt>' instruction takes an <a href="#t_integer">integer</a>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4882 value to cast, and a type to cast it to, which must be a
4883 <a href="#t_pointer">pointer</a> type.</p>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]4884
4885<h5>Semantics:</h5>
4886<p>The '<tt>inttoptr</tt>' instruction converts <tt>value</tt> to type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4887 <tt>ty2</tt> by applying either a zero extension or a truncation depending on
4888 the size of the integer <tt>value</tt>. If <tt>value</tt> is larger than the
4889 size of a pointer then a truncation is done. If <tt>value</tt> is smaller
4890 than the size of a pointer then a zero extension is done. If they are the
4891 same size, nothing is done (<i>no-op cast</i>).</p>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]4892
4893<h5>Example:</h5>
4894<pre>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]4895 %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]4896 %Y = inttoptr i32 255 to i32* <i>; yields no-op on 32-bit architecture</i>
4897 %Z = inttoptr i64 0 to i32* <i>; yields truncation 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">
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]4904 <a name="i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4905</div>
4906<div class="doc_text">
4907
4908<h5>Syntax:</h5>
4909<pre>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]4910 &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]4911</pre>
4912
4913<h5>Overview:</h5>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]4914<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4915 <tt>ty2</tt> without changing any bits.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4916
4917<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4918<p>The '<tt>bitcast</tt>' instruction takes a value to cast, which must be a
4919 non-aggregate first class value, and a type to cast it to, which must also be
4920 a non-aggregate <a href="#t_firstclass">first class</a> type. The bit sizes
4921 of <tt>value</tt> and the destination type, <tt>ty2</tt>, must be
4922 identical. If the source type is a pointer, the destination type must also be
4923 a pointer. This instruction supports bitwise conversion of vectors to
4924 integers and to vectors of other types (as long as they have the same
4925 size).</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4926
4927<h5>Semantics:</h5>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]4928<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4929 <tt>ty2</tt>. It is always a <i>no-op cast</i> because no bits change with
4930 this conversion. The conversion is done as if the <tt>value</tt> had been
4931 stored to memory and read back as type <tt>ty2</tt>. Pointer types may only
4932 be converted to other pointer types with this instruction. To convert
4933 pointers to other types, use the <a href="#i_inttoptr">inttoptr</a> or
4934 <a href="#i_ptrtoint">ptrtoint</a> instructions first.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4935
4936<h5>Example:</h5>
4937<pre>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]4938 %X = bitcast i8 255 to i8 <i>; yields i8 :-1</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4939 %Y = bitcast i32* %x to sint* <i>; yields sint*:%x</i>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4940 %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]4941</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4942
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4943</div>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]4944
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]4945<!-- ======================================================================= -->
4946<div class="doc_subsection"> <a name="otherops">Other Operations</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4947
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]4948<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4949
4950<p>The instructions in this category are the "miscellaneous" instructions, which
4951 defy better classification.</p>
4952
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]4953</div>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4954
4955<!-- _______________________________________________________________________ -->
4956<div class="doc_subsubsection"><a name="i_icmp">'<tt>icmp</tt>' Instruction</a>
4957</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4958
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4959<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4960
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4961<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4962<pre>
4963 &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]4964</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4965
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4966<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4967<p>The '<tt>icmp</tt>' instruction returns a boolean value or a vector of
4968 boolean values based on comparison of its two integer, integer vector, or
4969 pointer operands.</p>
4970
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4971<h5>Arguments:</h5>
4972<p>The '<tt>icmp</tt>' instruction takes three operands. The first operand is
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4973 the condition code indicating the kind of comparison to perform. It is not a
4974 value, just a keyword. The possible condition code are:</p>
4975
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4976<ol>
4977 <li><tt>eq</tt>: equal</li>
4978 <li><tt>ne</tt>: not equal </li>
4979 <li><tt>ugt</tt>: unsigned greater than</li>
4980 <li><tt>uge</tt>: unsigned greater or equal</li>
4981 <li><tt>ult</tt>: unsigned less than</li>
4982 <li><tt>ule</tt>: unsigned less or equal</li>
4983 <li><tt>sgt</tt>: signed greater than</li>
4984 <li><tt>sge</tt>: signed greater or equal</li>
4985 <li><tt>slt</tt>: signed less than</li>
4986 <li><tt>sle</tt>: signed less or equal</li>
4987</ol>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4988
Chris Lattnerc0f423a2007-01-15 01:54:13 +0000[diff] [blame]4989<p>The remaining two arguments must be <a href="#t_integer">integer</a> or
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4990 <a href="#t_pointer">pointer</a> or integer <a href="#t_vector">vector</a>
4991 typed. They must also be identical types.</p>
4992
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4993<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4994<p>The '<tt>icmp</tt>' compares <tt>op1</tt> and <tt>op2</tt> according to the
4995 condition code given as <tt>cond</tt>. The comparison performed always yields
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]4996 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]4997 result, as follows:</p>
4998
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4999<ol>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5000 <li><tt>eq</tt>: yields <tt>true</tt> if the operands are equal,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5001 <tt>false</tt> otherwise. No sign interpretation is necessary or
5002 performed.</li>
5003
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5004 <li><tt>ne</tt>: yields <tt>true</tt> if the operands are unequal,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5005 <tt>false</tt> otherwise. No sign interpretation is necessary or
5006 performed.</li>
5007
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5008 <li><tt>ugt</tt>: interprets the operands as unsigned values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5009 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
5010
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5011 <li><tt>uge</tt>: interprets the operands as unsigned values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5012 <tt>true</tt> if <tt>op1</tt> is greater than or equal
5013 to <tt>op2</tt>.</li>
5014
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5015 <li><tt>ult</tt>: interprets the operands as unsigned values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5016 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
5017
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5018 <li><tt>ule</tt>: interprets the operands as unsigned values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5019 <tt>true</tt> if <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
5020
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5021 <li><tt>sgt</tt>: interprets the operands as signed values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5022 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
5023
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5024 <li><tt>sge</tt>: interprets the operands as signed values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5025 <tt>true</tt> if <tt>op1</tt> is greater than or equal
5026 to <tt>op2</tt>.</li>
5027
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5028 <li><tt>slt</tt>: interprets the operands as signed values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5029 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
5030
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5031 <li><tt>sle</tt>: interprets the operands as signed values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5032 <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]5033</ol>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5034
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5035<p>If the operands are <a href="#t_pointer">pointer</a> typed, the pointer
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5036 values are compared as if they were integers.</p>
5037
5038<p>If the operands are integer vectors, then they are compared element by
5039 element. The result is an <tt>i1</tt> vector with the same number of elements
5040 as the values being compared. Otherwise, the result is an <tt>i1</tt>.</p>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5041
5042<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5043<pre>
5044 &lt;result&gt; = icmp eq i32 4, 5 <i>; yields: result=false</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]5045 &lt;result&gt; = icmp ne float* %X, %X <i>; yields: result=false</i>
5046 &lt;result&gt; = icmp ult i16 4, 5 <i>; yields: result=true</i>
5047 &lt;result&gt; = icmp sgt i16 4, 5 <i>; yields: result=false</i>
5048 &lt;result&gt; = icmp ule i16 -4, 5 <i>; yields: result=false</i>
5049 &lt;result&gt; = icmp sge i16 4, 5 <i>; yields: result=false</i>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5050</pre>
Dan Gohmana5127ab2009-01-22 01:39:38 +0000[diff] [blame]5051
5052<p>Note that the code generator does not yet support vector types with
5053 the <tt>icmp</tt> instruction.</p>
5054
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5055</div>
5056
5057<!-- _______________________________________________________________________ -->
5058<div class="doc_subsubsection"><a name="i_fcmp">'<tt>fcmp</tt>' Instruction</a>
5059</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5060
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5061<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5062
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5063<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5064<pre>
5065 &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]5066</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5067
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5068<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5069<p>The '<tt>fcmp</tt>' instruction returns a boolean value or vector of boolean
5070 values based on comparison of its operands.</p>
5071
5072<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]5073(<a href="#t_integer"><tt>i1</tt></a>).</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5074
5075<p>If the operands are floating point vectors, then the result type is a vector
5076 of boolean with the same number of elements as the operands being
5077 compared.</p>
5078
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5079<h5>Arguments:</h5>
5080<p>The '<tt>fcmp</tt>' instruction takes three operands. The first operand is
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5081 the condition code indicating the kind of comparison to perform. It is not a
5082 value, just a keyword. The possible condition code are:</p>
5083
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5084<ol>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]5085 <li><tt>false</tt>: no comparison, always returns false</li>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5086 <li><tt>oeq</tt>: ordered and equal</li>
5087 <li><tt>ogt</tt>: ordered and greater than </li>
5088 <li><tt>oge</tt>: ordered and greater than or equal</li>
5089 <li><tt>olt</tt>: ordered and less than </li>
5090 <li><tt>ole</tt>: ordered and less than or equal</li>
5091 <li><tt>one</tt>: ordered and not equal</li>
5092 <li><tt>ord</tt>: ordered (no nans)</li>
5093 <li><tt>ueq</tt>: unordered or equal</li>
5094 <li><tt>ugt</tt>: unordered or greater than </li>
5095 <li><tt>uge</tt>: unordered or greater than or equal</li>
5096 <li><tt>ult</tt>: unordered or less than </li>
5097 <li><tt>ule</tt>: unordered or less than or equal</li>
5098 <li><tt>une</tt>: unordered or not equal</li>
5099 <li><tt>uno</tt>: unordered (either nans)</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]5100 <li><tt>true</tt>: no comparison, always returns true</li>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5101</ol>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5102
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5103<p><i>Ordered</i> means that neither operand is a QNAN while
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5104 <i>unordered</i> means that either operand may be a QNAN.</p>
5105
5106<p>Each of <tt>val1</tt> and <tt>val2</tt> arguments must be either
5107 a <a href="#t_floating">floating point</a> type or
5108 a <a href="#t_vector">vector</a> of floating point type. They must have
5109 identical types.</p>
5110
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5111<h5>Semantics:</h5>
Gabor Greif0f75ad02008-08-07 21:46:00 +0000[diff] [blame]5112<p>The '<tt>fcmp</tt>' instruction compares <tt>op1</tt> and <tt>op2</tt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5113 according to the condition code given as <tt>cond</tt>. If the operands are
5114 vectors, then the vectors are compared element by element. Each comparison
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]5115 performed always yields an <a href="#t_integer">i1</a> result, as
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5116 follows:</p>
5117
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5118<ol>
5119 <li><tt>false</tt>: always yields <tt>false</tt>, regardless of operands.</li>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5120
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5121 <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]5122 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
5123
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]5124 <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]5125 <tt>op1</tt> is greater than <tt>op2</tt>.</li>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5126
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5127 <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]5128 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
5129
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5130 <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]5131 <tt>op1</tt> is less than <tt>op2</tt>.</li>
5132
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5133 <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]5134 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
5135
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5136 <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]5137 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
5138
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]5139 <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]5140
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5141 <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]5142 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
5143
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5144 <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]5145 <tt>op1</tt> is greater than <tt>op2</tt>.</li>
5146
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5147 <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]5148 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
5149
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5150 <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]5151 <tt>op1</tt> is less than <tt>op2</tt>.</li>
5152
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5153 <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]5154 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
5155
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5156 <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]5157 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
5158
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]5159 <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]5160
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5161 <li><tt>true</tt>: always yields <tt>true</tt>, regardless of operands.</li>
5162</ol>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5163
5164<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5165<pre>
5166 &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]5167 &lt;result&gt; = fcmp one float 4.0, 5.0 <i>; yields: result=true</i>
5168 &lt;result&gt; = fcmp olt float 4.0, 5.0 <i>; yields: result=true</i>
5169 &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]5170</pre>
Dan Gohmana5127ab2009-01-22 01:39:38 +0000[diff] [blame]5171
5172<p>Note that the code generator does not yet support vector types with
5173 the <tt>fcmp</tt> instruction.</p>
5174
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5175</div>
5176
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5177<!-- _______________________________________________________________________ -->
Nate Begemand2195702008-05-12 19:01:56 +0000[diff] [blame]5178<div class="doc_subsubsection">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]5179 <a name="i_phi">'<tt>phi</tt>' Instruction</a>
5180</div>
5181
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5182<div class="doc_text">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]5183
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5184<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5185<pre>
5186 &lt;result&gt; = phi &lt;ty&gt; [ &lt;val0&gt;, &lt;label0&gt;], ...
5187</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]5188
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5189<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5190<p>The '<tt>phi</tt>' instruction is used to implement the &#966; node in the
5191 SSA graph representing the function.</p>
5192
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5193<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5194<p>The type of the incoming values is specified with the first type field. After
5195 this, the '<tt>phi</tt>' instruction takes a list of pairs as arguments, with
5196 one pair for each predecessor basic block of the current block. Only values
5197 of <a href="#t_firstclass">first class</a> type may be used as the value
5198 arguments to the PHI node. Only labels may be used as the label
5199 arguments.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]5200
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5201<p>There must be no non-phi instructions between the start of a basic block and
5202 the PHI instructions: i.e. PHI instructions must be first in a basic
5203 block.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]5204
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5205<p>For the purposes of the SSA form, the use of each incoming value is deemed to
5206 occur on the edge from the corresponding predecessor block to the current
5207 block (but after any definition of an '<tt>invoke</tt>' instruction's return
5208 value on the same edge).</p>
Jay Foad1a4eea52009-06-03 10:20:10 +0000[diff] [blame]5209
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5210<h5>Semantics:</h5>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5211<p>At runtime, the '<tt>phi</tt>' instruction logically takes on the value
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5212 specified by the pair corresponding to the predecessor basic block that
5213 executed just prior to the current block.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]5214
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5215<h5>Example:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]5216<pre>
5217Loop: ; Infinite loop that counts from 0 on up...
5218 %indvar = phi i32 [ 0, %LoopHeader ], [ %nextindvar, %Loop ]
5219 %nextindvar = add i32 %indvar, 1
5220 br label %Loop
5221</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5222
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5223</div>
5224
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5225<!-- _______________________________________________________________________ -->
5226<div class="doc_subsubsection">
5227 <a name="i_select">'<tt>select</tt>' Instruction</a>
5228</div>
5229
5230<div class="doc_text">
5231
5232<h5>Syntax:</h5>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5233<pre>
Dan Gohmanc579d972008-09-09 01:02:47 +0000[diff] [blame]5234 &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>
5235
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]5236 <i>selty</i> is either i1 or {&lt;N x i1&gt;}
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5237</pre>
5238
5239<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5240<p>The '<tt>select</tt>' instruction is used to choose one value based on a
5241 condition, without branching.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5242
5243
5244<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5245<p>The '<tt>select</tt>' instruction requires an 'i1' value or a vector of 'i1'
5246 values indicating the condition, and two values of the
5247 same <a href="#t_firstclass">first class</a> type. If the val1/val2 are
5248 vectors and the condition is a scalar, then entire vectors are selected, not
5249 individual elements.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5250
5251<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5252<p>If the condition is an i1 and it evaluates to 1, the instruction returns the
5253 first value argument; otherwise, it returns the second value argument.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5254
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5255<p>If the condition is a vector of i1, then the value arguments must be vectors
5256 of the same size, and the selection is done element by element.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5257
5258<h5>Example:</h5>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5259<pre>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]5260 %X = select i1 true, i8 17, i8 42 <i>; yields i8:17</i>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5261</pre>
Dan Gohmana5127ab2009-01-22 01:39:38 +0000[diff] [blame]5262
5263<p>Note that the code generator does not yet support conditions
5264 with vector type.</p>
5265
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5266</div>
5267
Robert Bocchinof72fdfe2006-01-15 20:48:27 +0000[diff] [blame]5268<!-- _______________________________________________________________________ -->
5269<div class="doc_subsubsection">
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5270 <a name="i_call">'<tt>call</tt>' Instruction</a>
5271</div>
5272
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5273<div class="doc_text">
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5274
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]5275<h5>Syntax:</h5>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5276<pre>
Devang Patel02256232008-10-07 17:48:33 +0000[diff] [blame]5277 &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]5278</pre>
5279
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]5280<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5281<p>The '<tt>call</tt>' instruction represents a simple function call.</p>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5282
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]5283<h5>Arguments:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5284<p>This instruction requires several arguments:</p>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5285
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]5286<ol>
Jeffrey Yasskinb8677462010-01-09 19:44:16 +0000[diff] [blame]5287 <li>The optional "tail" marker indicates that the callee function does not
5288 access any allocas or varargs in the caller. Note that calls may be
5289 marked "tail" even if they do not occur before
5290 a <a href="#i_ret"><tt>ret</tt></a> instruction. If the "tail" marker is
5291 present, the function call is eligible for tail call optimization,
5292 but <a href="CodeGenerator.html#tailcallopt">might not in fact be
Evan Cheng59676492010-03-08 21:05:02 +0000[diff] [blame]5293 optimized into a jump</a>. The code generator may optimize calls marked
5294 "tail" with either 1) automatic <a href="CodeGenerator.html#sibcallopt">
5295 sibling call optimization</a> when the caller and callee have
5296 matching signatures, or 2) forced tail call optimization when the
5297 following extra requirements are met:
Jeffrey Yasskinb8677462010-01-09 19:44:16 +0000[diff] [blame]5298 <ul>
5299 <li>Caller and callee both have the calling
5300 convention <tt>fastcc</tt>.</li>
5301 <li>The call is in tail position (ret immediately follows call and ret
5302 uses value of call or is void).</li>
5303 <li>Option <tt>-tailcallopt</tt> is enabled,
Dan Gohman6232f732010-03-02 01:08:11 +0000[diff] [blame]5304 or <code>llvm::GuaranteedTailCallOpt</code> is <code>true</code>.</li>
Jeffrey Yasskinb8677462010-01-09 19:44:16 +0000[diff] [blame]5305 <li><a href="CodeGenerator.html#tailcallopt">Platform specific
5306 constraints are met.</a></li>
5307 </ul>
5308 </li>
Devang Patel7e9b05e2008-10-06 18:50:38 +0000[diff] [blame]5309
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5310 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
5311 convention</a> the call should use. If none is specified, the call
Jeffrey Yasskinb8677462010-01-09 19:44:16 +0000[diff] [blame]5312 defaults to using C calling conventions. The calling convention of the
5313 call must match the calling convention of the target function, or else the
5314 behavior is undefined.</li>
Devang Patel7e9b05e2008-10-06 18:50:38 +0000[diff] [blame]5315
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5316 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
5317 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
5318 '<tt>inreg</tt>' attributes are valid here.</li>
5319
5320 <li>'<tt>ty</tt>': the type of the call instruction itself which is also the
5321 type of the return value. Functions that return no value are marked
5322 <tt><a href="#t_void">void</a></tt>.</li>
5323
5324 <li>'<tt>fnty</tt>': shall be the signature of the pointer to function value
5325 being invoked. The argument types must match the types implied by this
5326 signature. This type can be omitted if the function is not varargs and if
5327 the function type does not return a pointer to a function.</li>
5328
5329 <li>'<tt>fnptrval</tt>': An LLVM value containing a pointer to a function to
5330 be invoked. In most cases, this is a direct function invocation, but
5331 indirect <tt>call</tt>s are just as possible, calling an arbitrary pointer
5332 to function value.</li>
5333
5334 <li>'<tt>function args</tt>': argument list whose types match the function
Chris Lattner47f2a832010-03-02 06:36:51 +0000[diff] [blame]5335 signature argument types and parameter attributes. All arguments must be
5336 of <a href="#t_firstclass">first class</a> type. If the function
5337 signature indicates the function accepts a variable number of arguments,
5338 the extra arguments can be specified.</li>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5339
5340 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
5341 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
5342 '<tt>readnone</tt>' attributes are valid here.</li>
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]5343</ol>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5344
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]5345<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5346<p>The '<tt>call</tt>' instruction is used to cause control flow to transfer to
5347 a specified function, with its incoming arguments bound to the specified
5348 values. Upon a '<tt><a href="#i_ret">ret</a></tt>' instruction in the called
5349 function, control flow continues with the instruction after the function
5350 call, and the return value of the function is bound to the result
5351 argument.</p>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5352
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]5353<h5>Example:</h5>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5354<pre>
Nick Lewyckya9b13d52007-09-08 13:57:50 +0000[diff] [blame]5355 %retval = call i32 @test(i32 %argc)
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]5356 call i32 (i8*, ...)* @printf(i8* %msg, i32 12, i8 42) <i>; yields i32</i>
Chris Lattnerfb7c88d2008-03-21 17:24:17 +0000[diff] [blame]5357 %X = tail call i32 @foo() <i>; yields i32</i>
5358 %Y = tail call <a href="#callingconv">fastcc</a> i32 @foo() <i>; yields i32</i>
5359 call void %foo(i8 97 signext)
Devang Pateld6cff512008-03-10 20:49:15 +0000[diff] [blame]5360
5361 %struct.A = type { i32, i8 }
Devang Patel7e9b05e2008-10-06 18:50:38 +0000[diff] [blame]5362 %r = call %struct.A @foo() <i>; yields { 32, i8 }</i>
Dan Gohmancc3132e2008-10-04 19:00:07 +0000[diff] [blame]5363 %gr = extractvalue %struct.A %r, 0 <i>; yields i32</i>
5364 %gr1 = extractvalue %struct.A %r, 1 <i>; yields i8</i>
Chris Lattner6cbe8e92008-10-08 06:26:11 +0000[diff] [blame]5365 %Z = call void @foo() noreturn <i>; indicates that %foo never returns normally</i>
Matthijs Kooijmaneefa7df2008-10-07 10:03:45 +0000[diff] [blame]5366 %ZZ = call zeroext i32 @bar() <i>; Return value is %zero extended</i>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5367</pre>
5368
Dale Johannesen68f971b2009-09-24 18:38:21 +0000[diff] [blame]5369<p>llvm treats calls to some functions with names and arguments that match the
Dale Johannesen722212d2009-09-25 17:04:42 +0000[diff] [blame]5370standard C99 library as being the C99 library functions, and may perform
5371optimizations or generate code for them under that assumption. This is
5372something we'd like to change in the future to provide better support for
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]5373freestanding environments and non-C-based languages.</p>
Dale Johannesen68f971b2009-09-24 18:38:21 +0000[diff] [blame]5374
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5375</div>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5376
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5377<!-- _______________________________________________________________________ -->
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5378<div class="doc_subsubsection">
Chris Lattner33337472006-01-13 23:26:01 +0000[diff] [blame]5379 <a name="i_va_arg">'<tt>va_arg</tt>' Instruction</a>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5380</div>
5381
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5382<div class="doc_text">
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5383
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]5384<h5>Syntax:</h5>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5385<pre>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]5386 &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]5387</pre>
5388
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]5389<h5>Overview:</h5>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]5390<p>The '<tt>va_arg</tt>' instruction is used to access arguments passed through
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5391 the "variable argument" area of a function call. It is used to implement the
5392 <tt>va_arg</tt> macro in C.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5393
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]5394<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5395<p>This instruction takes a <tt>va_list*</tt> value and the type of the
5396 argument. It returns a value of the specified argument type and increments
5397 the <tt>va_list</tt> to point to the next argument. The actual type
5398 of <tt>va_list</tt> is target specific.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5399
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]5400<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5401<p>The '<tt>va_arg</tt>' instruction loads an argument of the specified type
5402 from the specified <tt>va_list</tt> and causes the <tt>va_list</tt> to point
5403 to the next argument. For more information, see the variable argument
5404 handling <a href="#int_varargs">Intrinsic Functions</a>.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5405
5406<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]5407 take a variable number of arguments, for example, the <tt>vfprintf</tt>
5408 function.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5409
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5410<p><tt>va_arg</tt> is an LLVM instruction instead of
5411 an <a href="#intrinsics">intrinsic function</a> because it takes a type as an
5412 argument.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5413
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]5414<h5>Example:</h5>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5415<p>See the <a href="#int_varargs">variable argument processing</a> section.</p>
5416
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5417<p>Note that the code generator does not yet fully support va_arg on many
5418 targets. Also, it does not currently support va_arg with aggregate types on
5419 any target.</p>
Dan Gohman3065b612009-01-12 23:12:39 +0000[diff] [blame]5420
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5421</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5422
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5423<!-- *********************************************************************** -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]5424<div class="doc_section"> <a name="intrinsics">Intrinsic Functions</a> </div>
5425<!-- *********************************************************************** -->
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5426
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5427<div class="doc_text">
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5428
5429<p>LLVM supports the notion of an "intrinsic function". These functions have
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5430 well known names and semantics and are required to follow certain
5431 restrictions. Overall, these intrinsics represent an extension mechanism for
5432 the LLVM language that does not require changing all of the transformations
5433 in LLVM when adding to the language (or the bitcode reader/writer, the
5434 parser, etc...).</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5435
John Criswell88190562005-05-16 16:17:45 +0000[diff] [blame]5436<p>Intrinsic function names must all start with an "<tt>llvm.</tt>" prefix. This
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5437 prefix is reserved in LLVM for intrinsic names; thus, function names may not
5438 begin with this prefix. Intrinsic functions must always be external
5439 functions: you cannot define the body of intrinsic functions. Intrinsic
5440 functions may only be used in call or invoke instructions: it is illegal to
5441 take the address of an intrinsic function. Additionally, because intrinsic
5442 functions are part of the LLVM language, it is required if any are added that
5443 they be documented here.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5444
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5445<p>Some intrinsic functions can be overloaded, i.e., the intrinsic represents a
5446 family of functions that perform the same operation but on different data
5447 types. Because LLVM can represent over 8 million different integer types,
5448 overloading is used commonly to allow an intrinsic function to operate on any
5449 integer type. One or more of the argument types or the result type can be
5450 overloaded to accept any integer type. Argument types may also be defined as
5451 exactly matching a previous argument's type or the result type. This allows
5452 an intrinsic function which accepts multiple arguments, but needs all of them
5453 to be of the same type, to only be overloaded with respect to a single
5454 argument or the result.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5455
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5456<p>Overloaded intrinsics will have the names of its overloaded argument types
5457 encoded into its function name, each preceded by a period. Only those types
5458 which are overloaded result in a name suffix. Arguments whose type is matched
5459 against another type do not. For example, the <tt>llvm.ctpop</tt> function
5460 can take an integer of any width and returns an integer of exactly the same
5461 integer width. This leads to a family of functions such as
5462 <tt>i8 @llvm.ctpop.i8(i8 %val)</tt> and <tt>i29 @llvm.ctpop.i29(i29
5463 %val)</tt>. Only one type, the return type, is overloaded, and only one type
5464 suffix is required. Because the argument's type is matched against the return
5465 type, it does not require its own name suffix.</p>
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]5466
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5467<p>To learn how to add an intrinsic function, please see the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5468 <a href="ExtendingLLVM.html">Extending LLVM Guide</a>.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5469
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5470</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5471
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5472<!-- ======================================================================= -->
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5473<div class="doc_subsection">
5474 <a name="int_varargs">Variable Argument Handling Intrinsics</a>
5475</div>
5476
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5477<div class="doc_text">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5478
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5479<p>Variable argument support is defined in LLVM with
5480 the <a href="#i_va_arg"><tt>va_arg</tt></a> instruction and these three
5481 intrinsic functions. These functions are related to the similarly named
5482 macros defined in the <tt>&lt;stdarg.h&gt;</tt> header file.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5483
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5484<p>All of these functions operate on arguments that use a target-specific value
5485 type "<tt>va_list</tt>". The LLVM assembly language reference manual does
5486 not define what this type is, so all transformations should be prepared to
5487 handle these functions regardless of the type used.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5488
Chris Lattner30b868d2006-05-15 17:26:46 +0000[diff] [blame]5489<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]5490 instruction and the variable argument handling intrinsic functions are
5491 used.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5492
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]5493<pre class="doc_code">
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]5494define i32 @test(i32 %X, ...) {
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5495 ; Initialize variable argument processing
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5496 %ap = alloca i8*
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]5497 %ap2 = bitcast i8** %ap to i8*
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]5498 call void @llvm.va_start(i8* %ap2)
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5499
5500 ; Read a single integer argument
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5501 %tmp = va_arg i8** %ap, i32
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5502
5503 ; Demonstrate usage of llvm.va_copy and llvm.va_end
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5504 %aq = alloca i8*
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]5505 %aq2 = bitcast i8** %aq to i8*
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5506 call void @llvm.va_copy(i8* %aq2, i8* %ap2)
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]5507 call void @llvm.va_end(i8* %aq2)
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5508
5509 ; Stop processing of arguments.
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]5510 call void @llvm.va_end(i8* %ap2)
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]5511 ret i32 %tmp
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5512}
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]5513
5514declare void @llvm.va_start(i8*)
5515declare void @llvm.va_copy(i8*, i8*)
5516declare void @llvm.va_end(i8*)
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5517</pre>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5518
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]5519</div>
5520
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5521<!-- _______________________________________________________________________ -->
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5522<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5523 <a name="int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5524</div>
5525
5526
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5527<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5528
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5529<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5530<pre>
5531 declare void %llvm.va_start(i8* &lt;arglist&gt;)
5532</pre>
5533
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5534<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5535<p>The '<tt>llvm.va_start</tt>' intrinsic initializes <tt>*&lt;arglist&gt;</tt>
5536 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]5537
5538<h5>Arguments:</h5>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]5539<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]5540
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5541<h5>Semantics:</h5>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]5542<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]5543 macro available in C. In a target-dependent way, it initializes
5544 the <tt>va_list</tt> element to which the argument points, so that the next
5545 call to <tt>va_arg</tt> will produce the first variable argument passed to
5546 the function. Unlike the C <tt>va_start</tt> macro, this intrinsic does not
5547 need to know the last argument of the function as the compiler can figure
5548 that out.</p>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]5549
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5550</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5551
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5552<!-- _______________________________________________________________________ -->
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5553<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5554 <a name="int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5555</div>
5556
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5557<div class="doc_text">
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]5558
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5559<h5>Syntax:</h5>
5560<pre>
5561 declare void @llvm.va_end(i8* &lt;arglist&gt;)
5562</pre>
5563
5564<h5>Overview:</h5>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5565<p>The '<tt>llvm.va_end</tt>' intrinsic destroys <tt>*&lt;arglist&gt;</tt>,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5566 which has been initialized previously
5567 with <tt><a href="#int_va_start">llvm.va_start</a></tt>
5568 or <tt><a href="#i_va_copy">llvm.va_copy</a></tt>.</p>
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]5569
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5570<h5>Arguments:</h5>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5571<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]5572
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5573<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5574<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]5575 macro available in C. In a target-dependent way, it destroys
5576 the <tt>va_list</tt> element to which the argument points. Calls
5577 to <a href="#int_va_start"><tt>llvm.va_start</tt></a>
5578 and <a href="#int_va_copy"> <tt>llvm.va_copy</tt></a> must be matched exactly
5579 with calls to <tt>llvm.va_end</tt>.</p>
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]5580
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5581</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5582
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5583<!-- _______________________________________________________________________ -->
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5584<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5585 <a name="int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5586</div>
5587
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5588<div class="doc_text">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5589
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5590<h5>Syntax:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5591<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]5592 declare void @llvm.va_copy(i8* &lt;destarglist&gt;, i8* &lt;srcarglist&gt;)
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5593</pre>
5594
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5595<h5>Overview:</h5>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5596<p>The '<tt>llvm.va_copy</tt>' intrinsic copies the current argument position
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5597 from the source argument list to the destination argument list.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5598
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5599<h5>Arguments:</h5>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]5600<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]5601 The second argument is a pointer to a <tt>va_list</tt> element to copy
5602 from.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5603
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5604<h5>Semantics:</h5>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5605<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]5606 macro available in C. In a target-dependent way, it copies the
5607 source <tt>va_list</tt> element into the destination <tt>va_list</tt>
5608 element. This intrinsic is necessary because
5609 the <tt><a href="#int_va_start"> llvm.va_start</a></tt> intrinsic may be
5610 arbitrarily complex and require, for example, memory allocation.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5611
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5612</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5613
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5614<!-- ======================================================================= -->
5615<div class="doc_subsection">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5616 <a name="int_gc">Accurate Garbage Collection Intrinsics</a>
5617</div>
5618
5619<div class="doc_text">
5620
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5621<p>LLVM support for <a href="GarbageCollection.html">Accurate Garbage
Chris Lattner67c37d12008-08-05 18:29:16 +0000[diff] [blame]5622Collection</a> (GC) requires the implementation and generation of these
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5623intrinsics. These intrinsics allow identification of <a href="#int_gcroot">GC
5624roots on the stack</a>, as well as garbage collector implementations that
5625require <a href="#int_gcread">read</a> and <a href="#int_gcwrite">write</a>
5626barriers. Front-ends for type-safe garbage collected languages should generate
5627these intrinsics to make use of the LLVM garbage collectors. For more details,
5628see <a href="GarbageCollection.html">Accurate Garbage Collection with
5629LLVM</a>.</p>
Christopher Lamb55c6d4f2007-12-17 01:00:21 +0000[diff] [blame]5630
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5631<p>The garbage collection intrinsics only operate on objects in the generic
5632 address space (address space zero).</p>
Christopher Lamb55c6d4f2007-12-17 01:00:21 +0000[diff] [blame]5633
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5634</div>
5635
5636<!-- _______________________________________________________________________ -->
5637<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5638 <a name="int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5639</div>
5640
5641<div class="doc_text">
5642
5643<h5>Syntax:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5644<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]5645 declare void @llvm.gcroot(i8** %ptrloc, i8* %metadata)
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5646</pre>
5647
5648<h5>Overview:</h5>
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]5649<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]5650 the code generator, and allows some metadata to be associated with it.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5651
5652<h5>Arguments:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5653<p>The first argument specifies the address of a stack object that contains the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5654 root pointer. The second pointer (which must be either a constant or a
5655 global value address) contains the meta-data to be associated with the
5656 root.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5657
5658<h5>Semantics:</h5>
Chris Lattner851b7712008-04-24 05:59:56 +0000[diff] [blame]5659<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]5660 location. At compile-time, the code generator generates information to allow
5661 the runtime to find the pointer at GC safe points. The '<tt>llvm.gcroot</tt>'
5662 intrinsic may only be used in a function which <a href="#gc">specifies a GC
5663 algorithm</a>.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5664
5665</div>
5666
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5667<!-- _______________________________________________________________________ -->
5668<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5669 <a name="int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5670</div>
5671
5672<div class="doc_text">
5673
5674<h5>Syntax:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5675<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]5676 declare i8* @llvm.gcread(i8* %ObjPtr, i8** %Ptr)
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5677</pre>
5678
5679<h5>Overview:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5680<p>The '<tt>llvm.gcread</tt>' intrinsic identifies reads of references from heap
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5681 locations, allowing garbage collector implementations that require read
5682 barriers.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5683
5684<h5>Arguments:</h5>
Chris Lattnerf9228072006-03-14 20:02:51 +0000[diff] [blame]5685<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]5686 allocated from the garbage collector. The first object is a pointer to the
5687 start of the referenced object, if needed by the language runtime (otherwise
5688 null).</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5689
5690<h5>Semantics:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5691<p>The '<tt>llvm.gcread</tt>' intrinsic has the same semantics as a load
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5692 instruction, but may be replaced with substantially more complex code by the
5693 garbage collector runtime, as needed. The '<tt>llvm.gcread</tt>' intrinsic
5694 may only be used in a function which <a href="#gc">specifies a GC
5695 algorithm</a>.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5696
5697</div>
5698
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5699<!-- _______________________________________________________________________ -->
5700<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5701 <a name="int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5702</div>
5703
5704<div class="doc_text">
5705
5706<h5>Syntax:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5707<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]5708 declare void @llvm.gcwrite(i8* %P1, i8* %Obj, i8** %P2)
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5709</pre>
5710
5711<h5>Overview:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5712<p>The '<tt>llvm.gcwrite</tt>' intrinsic identifies writes of references to heap
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5713 locations, allowing garbage collector implementations that require write
5714 barriers (such as generational or reference counting collectors).</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5715
5716<h5>Arguments:</h5>
Chris Lattnerf9228072006-03-14 20:02:51 +0000[diff] [blame]5717<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]5718 object to store it to, and the third is the address of the field of Obj to
5719 store to. If the runtime does not require a pointer to the object, Obj may
5720 be null.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5721
5722<h5>Semantics:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5723<p>The '<tt>llvm.gcwrite</tt>' intrinsic has the same semantics as a store
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5724 instruction, but may be replaced with substantially more complex code by the
5725 garbage collector runtime, as needed. The '<tt>llvm.gcwrite</tt>' intrinsic
5726 may only be used in a function which <a href="#gc">specifies a GC
5727 algorithm</a>.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5728
5729</div>
5730
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5731<!-- ======================================================================= -->
5732<div class="doc_subsection">
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5733 <a name="int_codegen">Code Generator Intrinsics</a>
5734</div>
5735
5736<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5737
5738<p>These intrinsics are provided by LLVM to expose special features that may
5739 only be implemented with code generator support.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5740
5741</div>
5742
5743<!-- _______________________________________________________________________ -->
5744<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5745 <a name="int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5746</div>
5747
5748<div class="doc_text">
5749
5750<h5>Syntax:</h5>
5751<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]5752 declare i8 *@llvm.returnaddress(i32 &lt;level&gt;)
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5753</pre>
5754
5755<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5756<p>The '<tt>llvm.returnaddress</tt>' intrinsic attempts to compute a
5757 target-specific value indicating the return address of the current function
5758 or one of its callers.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5759
5760<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5761<p>The argument to this intrinsic indicates which function to return the address
5762 for. Zero indicates the calling function, one indicates its caller, etc.
5763 The argument is <b>required</b> to be a constant integer value.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5764
5765<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5766<p>The '<tt>llvm.returnaddress</tt>' intrinsic either returns a pointer
5767 indicating the return address of the specified call frame, or zero if it
5768 cannot be identified. The value returned by this intrinsic is likely to be
5769 incorrect or 0 for arguments other than zero, so it should only be used for
5770 debugging purposes.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5771
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5772<p>Note that calling this intrinsic does not prevent function inlining or other
5773 aggressive transformations, so the value returned may not be that of the
5774 obvious source-language caller.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5775
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5776</div>
5777
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5778<!-- _______________________________________________________________________ -->
5779<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5780 <a name="int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5781</div>
5782
5783<div class="doc_text">
5784
5785<h5>Syntax:</h5>
5786<pre>
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]5787 declare i8* @llvm.frameaddress(i32 &lt;level&gt;)
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5788</pre>
5789
5790<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5791<p>The '<tt>llvm.frameaddress</tt>' intrinsic attempts to return the
5792 target-specific frame pointer value for the specified stack frame.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5793
5794<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5795<p>The argument to this intrinsic indicates which function to return the frame
5796 pointer for. Zero indicates the calling function, one indicates its caller,
5797 etc. The argument is <b>required</b> to be a constant integer value.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5798
5799<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5800<p>The '<tt>llvm.frameaddress</tt>' intrinsic either returns a pointer
5801 indicating the frame address of the specified call frame, or zero if it
5802 cannot be identified. The value returned by this intrinsic is likely to be
5803 incorrect or 0 for arguments other than zero, so it should only be used for
5804 debugging purposes.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5805
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5806<p>Note that calling this intrinsic does not prevent function inlining or other
5807 aggressive transformations, so the value returned may not be that of the
5808 obvious source-language caller.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5809
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5810</div>
5811
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]5812<!-- _______________________________________________________________________ -->
5813<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5814 <a name="int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]5815</div>
5816
5817<div class="doc_text">
5818
5819<h5>Syntax:</h5>
5820<pre>
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]5821 declare i8* @llvm.stacksave()
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]5822</pre>
5823
5824<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5825<p>The '<tt>llvm.stacksave</tt>' intrinsic is used to remember the current state
5826 of the function stack, for use
5827 with <a href="#int_stackrestore"> <tt>llvm.stackrestore</tt></a>. This is
5828 useful for implementing language features like scoped automatic variable
5829 sized arrays in C99.</p>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]5830
5831<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5832<p>This intrinsic returns a opaque pointer value that can be passed
5833 to <a href="#int_stackrestore"><tt>llvm.stackrestore</tt></a>. When
5834 an <tt>llvm.stackrestore</tt> intrinsic is executed with a value saved
5835 from <tt>llvm.stacksave</tt>, it effectively restores the state of the stack
5836 to the state it was in when the <tt>llvm.stacksave</tt> intrinsic executed.
5837 In practice, this pops any <a href="#i_alloca">alloca</a> blocks from the
5838 stack that were allocated after the <tt>llvm.stacksave</tt> was executed.</p>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]5839
5840</div>
5841
5842<!-- _______________________________________________________________________ -->
5843<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5844 <a name="int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]5845</div>
5846
5847<div class="doc_text">
5848
5849<h5>Syntax:</h5>
5850<pre>
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]5851 declare void @llvm.stackrestore(i8* %ptr)
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]5852</pre>
5853
5854<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5855<p>The '<tt>llvm.stackrestore</tt>' intrinsic is used to restore the state of
5856 the function stack to the state it was in when the
5857 corresponding <a href="#int_stacksave"><tt>llvm.stacksave</tt></a> intrinsic
5858 executed. This is useful for implementing language features like scoped
5859 automatic variable sized arrays in C99.</p>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]5860
5861<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5862<p>See the description
5863 for <a href="#int_stacksave"><tt>llvm.stacksave</tt></a>.</p>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]5864
5865</div>
5866
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]5867<!-- _______________________________________________________________________ -->
5868<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5869 <a name="int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a>
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]5870</div>
5871
5872<div class="doc_text">
5873
5874<h5>Syntax:</h5>
5875<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]5876 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]5877</pre>
5878
5879<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5880<p>The '<tt>llvm.prefetch</tt>' intrinsic is a hint to the code generator to
5881 insert a prefetch instruction if supported; otherwise, it is a noop.
5882 Prefetches have no effect on the behavior of the program but can change its
5883 performance characteristics.</p>
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]5884
5885<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5886<p><tt>address</tt> is the address to be prefetched, <tt>rw</tt> is the
5887 specifier determining if the fetch should be for a read (0) or write (1),
5888 and <tt>locality</tt> is a temporal locality specifier ranging from (0) - no
5889 locality, to (3) - extremely local keep in cache. The <tt>rw</tt>
5890 and <tt>locality</tt> arguments must be constant integers.</p>
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]5891
5892<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5893<p>This intrinsic does not modify the behavior of the program. In particular,
5894 prefetches cannot trap and do not produce a value. On targets that support
5895 this intrinsic, the prefetch can provide hints to the processor cache for
5896 better performance.</p>
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]5897
5898</div>
5899
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]5900<!-- _______________________________________________________________________ -->
5901<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5902 <a name="int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a>
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]5903</div>
5904
5905<div class="doc_text">
5906
5907<h5>Syntax:</h5>
5908<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]5909 declare void @llvm.pcmarker(i32 &lt;id&gt;)
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]5910</pre>
5911
5912<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5913<p>The '<tt>llvm.pcmarker</tt>' intrinsic is a method to export a Program
5914 Counter (PC) in a region of code to simulators and other tools. The method
5915 is target specific, but it is expected that the marker will use exported
5916 symbols to transmit the PC of the marker. The marker makes no guarantees
5917 that it will remain with any specific instruction after optimizations. It is
5918 possible that the presence of a marker will inhibit optimizations. The
5919 intended use is to be inserted after optimizations to allow correlations of
5920 simulation runs.</p>
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]5921
5922<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5923<p><tt>id</tt> is a numerical id identifying the marker.</p>
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]5924
5925<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5926<p>This intrinsic does not modify the behavior of the program. Backends that do
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]5927 not support this intrinsic may ignore it.</p>
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]5928
5929</div>
5930
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]5931<!-- _______________________________________________________________________ -->
5932<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5933 <a name="int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a>
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]5934</div>
5935
5936<div class="doc_text">
5937
5938<h5>Syntax:</h5>
5939<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]5940 declare i64 @llvm.readcyclecounter()
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]5941</pre>
5942
5943<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5944<p>The '<tt>llvm.readcyclecounter</tt>' intrinsic provides access to the cycle
5945 counter register (or similar low latency, high accuracy clocks) on those
5946 targets that support it. On X86, it should map to RDTSC. On Alpha, it
5947 should map to RPCC. As the backing counters overflow quickly (on the order
5948 of 9 seconds on alpha), this should only be used for small timings.</p>
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]5949
5950<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5951<p>When directly supported, reading the cycle counter should not modify any
5952 memory. Implementations are allowed to either return a application specific
5953 value or a system wide value. On backends without support, this is lowered
5954 to a constant 0.</p>
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]5955
5956</div>
5957
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5958<!-- ======================================================================= -->
5959<div class="doc_subsection">
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5960 <a name="int_libc">Standard C Library Intrinsics</a>
5961</div>
5962
5963<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5964
5965<p>LLVM provides intrinsics for a few important standard C library functions.
5966 These intrinsics allow source-language front-ends to pass information about
5967 the alignment of the pointer arguments to the code generator, providing
5968 opportunity for more efficient code generation.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5969
5970</div>
5971
5972<!-- _______________________________________________________________________ -->
5973<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5974 <a name="int_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5975</div>
5976
5977<div class="doc_text">
5978
5979<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5980<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]5981 integer bit width and for different address spaces. Not all targets support
5982 all bit widths however.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5983
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5984<pre>
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]5985 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]5986 i32 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]5987 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]5988 i64 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5989</pre>
5990
5991<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5992<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
5993 source location to the destination location.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5994
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5995<p>Note that, unlike the standard libc function, the <tt>llvm.memcpy.*</tt>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]5996 intrinsics do not return a value, takes extra alignment/isvolatile arguments
5997 and the pointers can be in specified address spaces.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5998
5999<h5>Arguments:</h5>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6000
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6001<p>The first argument is a pointer to the destination, the second is a pointer
6002 to the source. The third argument is an integer argument specifying the
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6003 number of bytes to copy, the fourth argument is the alignment of the
6004 source and destination locations, and the fifth is a boolean indicating a
6005 volatile access.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6006
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]6007<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]6008 then the caller guarantees that both the source and destination pointers are
6009 aligned to that boundary.</p>
Chris Lattner4c67c482004-02-12 21:18:15 +0000[diff] [blame]6010
Jeffrey Yasskin5d284ae2010-04-26 21:21:24 +0000[diff] [blame]6011<p>If the <tt>isvolatile</tt> parameter is <tt>true</tt>, the
6012 <tt>llvm.memcpy</tt> call is a <a href="#volatile">volatile operation</a>.
6013 The detailed access behavior is not very cleanly specified and it is unwise
6014 to depend on it.</p>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6015
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6016<h5>Semantics:</h5>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6017
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6018<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
6019 source location to the destination location, which are not allowed to
6020 overlap. It copies "len" bytes of memory over. If the argument is known to
6021 be aligned to some boundary, this can be specified as the fourth argument,
6022 otherwise it should be set to 0 or 1.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6023
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6024</div>
6025
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6026<!-- _______________________________________________________________________ -->
6027<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6028 <a name="int_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a>
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6029</div>
6030
6031<div class="doc_text">
6032
6033<h5>Syntax:</h5>
Chris Lattnerdd708342008-11-21 16:42:48 +0000[diff] [blame]6034<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]6035 width and for different address space. Not all targets support all bit
6036 widths however.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6037
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6038<pre>
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]6039 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]6040 i32 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]6041 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]6042 i64 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6043</pre>
6044
6045<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6046<p>The '<tt>llvm.memmove.*</tt>' intrinsics move a block of memory from the
6047 source location to the destination location. It is similar to the
6048 '<tt>llvm.memcpy</tt>' intrinsic but allows the two memory locations to
6049 overlap.</p>
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6050
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6051<p>Note that, unlike the standard libc function, the <tt>llvm.memmove.*</tt>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6052 intrinsics do not return a value, takes extra alignment/isvolatile arguments
6053 and the pointers can be in specified address spaces.</p>
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6054
6055<h5>Arguments:</h5>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6056
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6057<p>The first argument is a pointer to the destination, the second is a pointer
6058 to the source. The third argument is an integer argument specifying the
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6059 number of bytes to copy, the fourth argument is the alignment of the
6060 source and destination locations, and the fifth is a boolean indicating a
6061 volatile access.</p>
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6062
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]6063<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]6064 then the caller guarantees that the source and destination pointers are
6065 aligned to that boundary.</p>
Chris Lattner4c67c482004-02-12 21:18:15 +0000[diff] [blame]6066
Jeffrey Yasskin5d284ae2010-04-26 21:21:24 +0000[diff] [blame]6067<p>If the <tt>isvolatile</tt> parameter is <tt>true</tt>, the
6068 <tt>llvm.memmove</tt> call is a <a href="#volatile">volatile operation</a>.
6069 The detailed access behavior is not very cleanly specified and it is unwise
6070 to depend on it.</p>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6071
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6072<h5>Semantics:</h5>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6073
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6074<p>The '<tt>llvm.memmove.*</tt>' intrinsics copy a block of memory from the
6075 source location to the destination location, which may overlap. It copies
6076 "len" bytes of memory over. If the argument is known to be aligned to some
6077 boundary, this can be specified as the fourth argument, otherwise it should
6078 be set to 0 or 1.</p>
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6079
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6080</div>
6081
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6082<!-- _______________________________________________________________________ -->
6083<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6084 <a name="int_memset">'<tt>llvm.memset.*</tt>' Intrinsics</a>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6085</div>
6086
6087<div class="doc_text">
6088
6089<h5>Syntax:</h5>
Chris Lattnerdd708342008-11-21 16:42:48 +0000[diff] [blame]6090<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]6091 width and for different address spaces. However, not all targets support all
6092 bit widths.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6093
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6094<pre>
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]6095 declare void @llvm.memset.p0i8.i32(i8* &lt;dest&gt;, i8 &lt;val&gt;,
Chris Lattner685db9d2010-04-08 00:54:34 +0000[diff] [blame]6096 i32 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]6097 declare void @llvm.memset.p0i8.i64(i8* &lt;dest&gt;, i8 &lt;val&gt;,
Chris Lattner685db9d2010-04-08 00:54:34 +0000[diff] [blame]6098 i64 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6099</pre>
6100
6101<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6102<p>The '<tt>llvm.memset.*</tt>' intrinsics fill a block of memory with a
6103 particular byte value.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6104
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6105<p>Note that, unlike the standard libc function, the <tt>llvm.memset</tt>
John Criswellad05ae42010-07-30 16:30:28 +0000[diff] [blame]6106 intrinsic does not return a value and takes extra alignment/volatile
6107 arguments. Also, the destination can be in an arbitrary address space.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6108
6109<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6110<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]6111 byte value with which to fill it, the third argument is an integer argument
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6112 specifying the number of bytes to fill, and the fourth argument is the known
John Criswellad05ae42010-07-30 16:30:28 +0000[diff] [blame]6113 alignment of the destination location.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6114
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]6115<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]6116 then the caller guarantees that the destination pointer is aligned to that
6117 boundary.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6118
Jeffrey Yasskin5d284ae2010-04-26 21:21:24 +0000[diff] [blame]6119<p>If the <tt>isvolatile</tt> parameter is <tt>true</tt>, the
6120 <tt>llvm.memset</tt> call is a <a href="#volatile">volatile operation</a>.
6121 The detailed access behavior is not very cleanly specified and it is unwise
6122 to depend on it.</p>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6123
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6124<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6125<p>The '<tt>llvm.memset.*</tt>' intrinsics fill "len" bytes of memory starting
6126 at the destination location. If the argument is known to be aligned to some
6127 boundary, this can be specified as the fourth argument, otherwise it should
6128 be set to 0 or 1.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6129
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6130</div>
6131
Chris Lattner3b4f4372004-06-11 02:28:03 +0000[diff] [blame]6132<!-- _______________________________________________________________________ -->
6133<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6134 <a name="int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a>
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]6135</div>
6136
6137<div class="doc_text">
6138
6139<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6140<p>This is an overloaded intrinsic. You can use <tt>llvm.sqrt</tt> on any
6141 floating point or vector of floating point type. Not all targets support all
6142 types however.</p>
6143
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]6144<pre>
Dale Johannesendd89d272007-10-02 17:47:38 +0000[diff] [blame]6145 declare float @llvm.sqrt.f32(float %Val)
6146 declare double @llvm.sqrt.f64(double %Val)
6147 declare x86_fp80 @llvm.sqrt.f80(x86_fp80 %Val)
6148 declare fp128 @llvm.sqrt.f128(fp128 %Val)
6149 declare ppc_fp128 @llvm.sqrt.ppcf128(ppc_fp128 %Val)
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]6150</pre>
6151
6152<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6153<p>The '<tt>llvm.sqrt</tt>' intrinsics return the sqrt of the specified operand,
6154 returning the same value as the libm '<tt>sqrt</tt>' functions would.
6155 Unlike <tt>sqrt</tt> in libm, however, <tt>llvm.sqrt</tt> has undefined
6156 behavior for negative numbers other than -0.0 (which allows for better
6157 optimization, because there is no need to worry about errno being
6158 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]6159
6160<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6161<p>The argument and return value are floating point numbers of the same
6162 type.</p>
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]6163
6164<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6165<p>This function returns the sqrt of the specified operand if it is a
6166 nonnegative floating point number.</p>
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]6167
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]6168</div>
6169
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]6170<!-- _______________________________________________________________________ -->
6171<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6172 <a name="int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a>
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]6173</div>
6174
6175<div class="doc_text">
6176
6177<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6178<p>This is an overloaded intrinsic. You can use <tt>llvm.powi</tt> on any
6179 floating point or vector of floating point type. Not all targets support all
6180 types however.</p>
6181
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]6182<pre>
Dale Johannesendd89d272007-10-02 17:47:38 +0000[diff] [blame]6183 declare float @llvm.powi.f32(float %Val, i32 %power)
6184 declare double @llvm.powi.f64(double %Val, i32 %power)
6185 declare x86_fp80 @llvm.powi.f80(x86_fp80 %Val, i32 %power)
6186 declare fp128 @llvm.powi.f128(fp128 %Val, i32 %power)
6187 declare ppc_fp128 @llvm.powi.ppcf128(ppc_fp128 %Val, i32 %power)
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]6188</pre>
6189
6190<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6191<p>The '<tt>llvm.powi.*</tt>' intrinsics return the first operand raised to the
6192 specified (positive or negative) power. The order of evaluation of
6193 multiplications is not defined. When a vector of floating point type is
6194 used, the second argument remains a scalar integer value.</p>
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]6195
6196<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6197<p>The second argument is an integer power, and the first is a value to raise to
6198 that power.</p>
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]6199
6200<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6201<p>This function returns the first value raised to the second power with an
6202 unspecified sequence of rounding operations.</p>
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]6203
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]6204</div>
6205
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6206<!-- _______________________________________________________________________ -->
6207<div class="doc_subsubsection">
6208 <a name="int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a>
6209</div>
6210
6211<div class="doc_text">
6212
6213<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6214<p>This is an overloaded intrinsic. You can use <tt>llvm.sin</tt> on any
6215 floating point or vector of floating point type. Not all targets support all
6216 types however.</p>
6217
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6218<pre>
6219 declare float @llvm.sin.f32(float %Val)
6220 declare double @llvm.sin.f64(double %Val)
6221 declare x86_fp80 @llvm.sin.f80(x86_fp80 %Val)
6222 declare fp128 @llvm.sin.f128(fp128 %Val)
6223 declare ppc_fp128 @llvm.sin.ppcf128(ppc_fp128 %Val)
6224</pre>
6225
6226<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6227<p>The '<tt>llvm.sin.*</tt>' intrinsics return the sine of the operand.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6228
6229<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6230<p>The argument and return value are floating point numbers of the same
6231 type.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6232
6233<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6234<p>This function returns the sine of the specified operand, returning the same
6235 values as the libm <tt>sin</tt> functions would, and handles error conditions
6236 in the same way.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6237
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6238</div>
6239
6240<!-- _______________________________________________________________________ -->
6241<div class="doc_subsubsection">
6242 <a name="int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a>
6243</div>
6244
6245<div class="doc_text">
6246
6247<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6248<p>This is an overloaded intrinsic. You can use <tt>llvm.cos</tt> on any
6249 floating point or vector of floating point type. Not all targets support all
6250 types however.</p>
6251
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6252<pre>
6253 declare float @llvm.cos.f32(float %Val)
6254 declare double @llvm.cos.f64(double %Val)
6255 declare x86_fp80 @llvm.cos.f80(x86_fp80 %Val)
6256 declare fp128 @llvm.cos.f128(fp128 %Val)
6257 declare ppc_fp128 @llvm.cos.ppcf128(ppc_fp128 %Val)
6258</pre>
6259
6260<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6261<p>The '<tt>llvm.cos.*</tt>' intrinsics return the cosine of the operand.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6262
6263<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6264<p>The argument and return value are floating point numbers of the same
6265 type.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6266
6267<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6268<p>This function returns the cosine of the specified operand, returning the same
6269 values as the libm <tt>cos</tt> functions would, and handles error conditions
6270 in the same way.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6271
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6272</div>
6273
6274<!-- _______________________________________________________________________ -->
6275<div class="doc_subsubsection">
6276 <a name="int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a>
6277</div>
6278
6279<div class="doc_text">
6280
6281<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6282<p>This is an overloaded intrinsic. You can use <tt>llvm.pow</tt> on any
6283 floating point or vector of floating point type. Not all targets support all
6284 types however.</p>
6285
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6286<pre>
6287 declare float @llvm.pow.f32(float %Val, float %Power)
6288 declare double @llvm.pow.f64(double %Val, double %Power)
6289 declare x86_fp80 @llvm.pow.f80(x86_fp80 %Val, x86_fp80 %Power)
6290 declare fp128 @llvm.pow.f128(fp128 %Val, fp128 %Power)
6291 declare ppc_fp128 @llvm.pow.ppcf128(ppc_fp128 %Val, ppc_fp128 Power)
6292</pre>
6293
6294<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6295<p>The '<tt>llvm.pow.*</tt>' intrinsics return the first operand raised to the
6296 specified (positive or negative) power.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6297
6298<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6299<p>The second argument is a floating point power, and the first is a value to
6300 raise to that power.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6301
6302<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6303<p>This function returns the first value raised to the second power, returning
6304 the same values as the libm <tt>pow</tt> functions would, and handles error
6305 conditions in the same way.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6306
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6307</div>
6308
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6309<!-- ======================================================================= -->
6310<div class="doc_subsection">
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]6311 <a name="int_manip">Bit Manipulation Intrinsics</a>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6312</div>
6313
6314<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6315
6316<p>LLVM provides intrinsics for a few important bit manipulation operations.
6317 These allow efficient code generation for some algorithms.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6318
6319</div>
6320
6321<!-- _______________________________________________________________________ -->
6322<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6323 <a name="int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a>
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]6324</div>
6325
6326<div class="doc_text">
6327
6328<h5>Syntax:</h5>
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]6329<p>This is an overloaded intrinsic function. You can use bswap on any integer
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6330 type that is an even number of bytes (i.e. BitWidth % 16 == 0).</p>
6331
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]6332<pre>
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]6333 declare i16 @llvm.bswap.i16(i16 &lt;id&gt;)
6334 declare i32 @llvm.bswap.i32(i32 &lt;id&gt;)
6335 declare i64 @llvm.bswap.i64(i64 &lt;id&gt;)
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]6336</pre>
6337
6338<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6339<p>The '<tt>llvm.bswap</tt>' family of intrinsics is used to byte swap integer
6340 values with an even number of bytes (positive multiple of 16 bits). These
6341 are useful for performing operations on data that is not in the target's
6342 native byte order.</p>
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]6343
6344<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6345<p>The <tt>llvm.bswap.i16</tt> intrinsic returns an i16 value that has the high
6346 and low byte of the input i16 swapped. Similarly,
6347 the <tt>llvm.bswap.i32</tt> intrinsic returns an i32 value that has the four
6348 bytes of the input i32 swapped, so that if the input bytes are numbered 0, 1,
6349 2, 3 then the returned i32 will have its bytes in 3, 2, 1, 0 order.
6350 The <tt>llvm.bswap.i48</tt>, <tt>llvm.bswap.i64</tt> and other intrinsics
6351 extend this concept to additional even-byte lengths (6 bytes, 8 bytes and
6352 more, respectively).</p>
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]6353
6354</div>
6355
6356<!-- _______________________________________________________________________ -->
6357<div class="doc_subsubsection">
Reid Spencerb4f9a6f2006-01-16 21:12:35 +0000[diff] [blame]6358 <a name="int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic</a>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6359</div>
6360
6361<div class="doc_text">
6362
6363<h5>Syntax:</h5>
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]6364<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]6365 width. Not all targets support all bit widths however.</p>
6366
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6367<pre>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6368 declare i8 @llvm.ctpop.i8(i8 &lt;src&gt;)
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]6369 declare i16 @llvm.ctpop.i16(i16 &lt;src&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]6370 declare i32 @llvm.ctpop.i32(i32 &lt;src&gt;)
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]6371 declare i64 @llvm.ctpop.i64(i64 &lt;src&gt;)
6372 declare i256 @llvm.ctpop.i256(i256 &lt;src&gt;)
Andrew Lenharth1d463522005-05-03 18:01:48 +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.ctpop</tt>' family of intrinsics counts the number of bits set
6377 in a value.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6378
6379<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6380<p>The only argument is the value to be counted. The argument may be of any
6381 integer type. The return type must match the argument type.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6382
6383<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6384<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]6385
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6386</div>
6387
6388<!-- _______________________________________________________________________ -->
6389<div class="doc_subsubsection">
Chris Lattnerb748c672006-01-16 22:34:14 +0000[diff] [blame]6390 <a name="int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic</a>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6391</div>
6392
6393<div class="doc_text">
6394
6395<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6396<p>This is an overloaded intrinsic. You can use <tt>llvm.ctlz</tt> on any
6397 integer bit width. Not all targets support all bit widths however.</p>
6398
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6399<pre>
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]6400 declare i8 @llvm.ctlz.i8 (i8 &lt;src&gt;)
6401 declare i16 @llvm.ctlz.i16(i16 &lt;src&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]6402 declare i32 @llvm.ctlz.i32(i32 &lt;src&gt;)
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]6403 declare i64 @llvm.ctlz.i64(i64 &lt;src&gt;)
6404 declare i256 @llvm.ctlz.i256(i256 &lt;src&gt;)
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6405</pre>
6406
6407<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6408<p>The '<tt>llvm.ctlz</tt>' family of intrinsic functions counts the number of
6409 leading zeros in a variable.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6410
6411<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6412<p>The only argument is the value to be counted. The argument may be of any
6413 integer type. The return type must match the argument type.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6414
6415<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6416<p>The '<tt>llvm.ctlz</tt>' intrinsic counts the leading (most significant)
6417 zeros in a variable. If the src == 0 then the result is the size in bits of
6418 the type of src. For example, <tt>llvm.ctlz(i32 2) = 30</tt>.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6419
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6420</div>
Chris Lattner3b4f4372004-06-11 02:28:03 +0000[diff] [blame]6421
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]6422<!-- _______________________________________________________________________ -->
6423<div class="doc_subsubsection">
Chris Lattnerb748c672006-01-16 22:34:14 +0000[diff] [blame]6424 <a name="int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic</a>
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]6425</div>
6426
6427<div class="doc_text">
6428
6429<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6430<p>This is an overloaded intrinsic. You can use <tt>llvm.cttz</tt> on any
6431 integer bit width. Not all targets support all bit widths however.</p>
6432
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]6433<pre>
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]6434 declare i8 @llvm.cttz.i8 (i8 &lt;src&gt;)
6435 declare i16 @llvm.cttz.i16(i16 &lt;src&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]6436 declare i32 @llvm.cttz.i32(i32 &lt;src&gt;)
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]6437 declare i64 @llvm.cttz.i64(i64 &lt;src&gt;)
6438 declare i256 @llvm.cttz.i256(i256 &lt;src&gt;)
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]6439</pre>
6440
6441<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6442<p>The '<tt>llvm.cttz</tt>' family of intrinsic functions counts the number of
6443 trailing zeros.</p>
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]6444
6445<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6446<p>The only argument is the value to be counted. The argument may be of any
6447 integer type. The return type must match the argument type.</p>
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]6448
6449<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6450<p>The '<tt>llvm.cttz</tt>' intrinsic counts the trailing (least significant)
6451 zeros in a variable. If the src == 0 then the result is the size in bits of
6452 the type of src. For example, <tt>llvm.cttz(2) = 1</tt>.</p>
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]6453
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]6454</div>
6455
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]6456<!-- ======================================================================= -->
6457<div class="doc_subsection">
6458 <a name="int_overflow">Arithmetic with Overflow Intrinsics</a>
6459</div>
6460
6461<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6462
6463<p>LLVM provides intrinsics for some arithmetic with overflow operations.</p>
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]6464
6465</div>
6466
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6467<!-- _______________________________________________________________________ -->
6468<div class="doc_subsubsection">
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]6469 <a name="int_sadd_overflow">'<tt>llvm.sadd.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6470</div>
6471
6472<div class="doc_text">
6473
6474<h5>Syntax:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6475<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]6476 on any integer bit width.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6477
6478<pre>
6479 declare {i16, i1} @llvm.sadd.with.overflow.i16(i16 %a, i16 %b)
6480 declare {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
6481 declare {i64, i1} @llvm.sadd.with.overflow.i64(i64 %a, i64 %b)
6482</pre>
6483
6484<h5>Overview:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6485<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6486 a signed addition of the two arguments, and indicate whether an overflow
6487 occurred during the signed summation.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6488
6489<h5>Arguments:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6490<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]6491 be of integer types of any bit width, but they must have the same bit
6492 width. The second element of the result structure must be of
6493 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6494 undergo signed addition.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6495
6496<h5>Semantics:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6497<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6498 a signed addition of the two variables. They return a structure &mdash; the
6499 first element of which is the signed summation, and the second element of
6500 which is a bit specifying if the signed summation resulted in an
6501 overflow.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6502
6503<h5>Examples:</h5>
6504<pre>
6505 %res = call {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
6506 %sum = extractvalue {i32, i1} %res, 0
6507 %obit = extractvalue {i32, i1} %res, 1
6508 br i1 %obit, label %overflow, label %normal
6509</pre>
6510
6511</div>
6512
6513<!-- _______________________________________________________________________ -->
6514<div class="doc_subsubsection">
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]6515 <a name="int_uadd_overflow">'<tt>llvm.uadd.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6516</div>
6517
6518<div class="doc_text">
6519
6520<h5>Syntax:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6521<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]6522 on any integer bit width.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6523
6524<pre>
6525 declare {i16, i1} @llvm.uadd.with.overflow.i16(i16 %a, i16 %b)
6526 declare {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
6527 declare {i64, i1} @llvm.uadd.with.overflow.i64(i64 %a, i64 %b)
6528</pre>
6529
6530<h5>Overview:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6531<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6532 an unsigned addition of the two arguments, and indicate whether a carry
6533 occurred during the unsigned summation.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6534
6535<h5>Arguments:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6536<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]6537 be of integer types of any bit width, but they must have the same bit
6538 width. The second element of the result structure must be of
6539 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6540 undergo unsigned addition.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6541
6542<h5>Semantics:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6543<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6544 an unsigned addition of the two arguments. They return a structure &mdash;
6545 the first element of which is the sum, and the second element of which is a
6546 bit specifying if the unsigned summation resulted in a carry.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6547
6548<h5>Examples:</h5>
6549<pre>
6550 %res = call {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
6551 %sum = extractvalue {i32, i1} %res, 0
6552 %obit = extractvalue {i32, i1} %res, 1
6553 br i1 %obit, label %carry, label %normal
6554</pre>
6555
6556</div>
6557
6558<!-- _______________________________________________________________________ -->
6559<div class="doc_subsubsection">
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]6560 <a name="int_ssub_overflow">'<tt>llvm.ssub.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6561</div>
6562
6563<div class="doc_text">
6564
6565<h5>Syntax:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6566<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]6567 on any integer bit width.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6568
6569<pre>
6570 declare {i16, i1} @llvm.ssub.with.overflow.i16(i16 %a, i16 %b)
6571 declare {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
6572 declare {i64, i1} @llvm.ssub.with.overflow.i64(i64 %a, i64 %b)
6573</pre>
6574
6575<h5>Overview:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6576<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6577 a signed subtraction of the two arguments, and indicate whether an overflow
6578 occurred during the signed subtraction.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6579
6580<h5>Arguments:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6581<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]6582 be of integer types of any bit width, but they must have the same bit
6583 width. The second element of the result structure must be of
6584 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6585 undergo signed subtraction.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6586
6587<h5>Semantics:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6588<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6589 a signed subtraction of the two arguments. They return a structure &mdash;
6590 the first element of which is the subtraction, and the second element of
6591 which is a bit specifying if the signed subtraction resulted in an
6592 overflow.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6593
6594<h5>Examples:</h5>
6595<pre>
6596 %res = call {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
6597 %sum = extractvalue {i32, i1} %res, 0
6598 %obit = extractvalue {i32, i1} %res, 1
6599 br i1 %obit, label %overflow, label %normal
6600</pre>
6601
6602</div>
6603
6604<!-- _______________________________________________________________________ -->
6605<div class="doc_subsubsection">
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]6606 <a name="int_usub_overflow">'<tt>llvm.usub.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6607</div>
6608
6609<div class="doc_text">
6610
6611<h5>Syntax:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6612<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]6613 on any integer bit width.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6614
6615<pre>
6616 declare {i16, i1} @llvm.usub.with.overflow.i16(i16 %a, i16 %b)
6617 declare {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
6618 declare {i64, i1} @llvm.usub.with.overflow.i64(i64 %a, i64 %b)
6619</pre>
6620
6621<h5>Overview:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6622<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6623 an unsigned subtraction of the two arguments, and indicate whether an
6624 overflow occurred during the unsigned subtraction.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6625
6626<h5>Arguments:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6627<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]6628 be of integer types of any bit width, but they must have the same bit
6629 width. The second element of the result structure must be of
6630 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6631 undergo unsigned subtraction.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6632
6633<h5>Semantics:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6634<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6635 an unsigned subtraction of the two arguments. They return a structure &mdash;
6636 the first element of which is the subtraction, and the second element of
6637 which is a bit specifying if the unsigned subtraction resulted in an
6638 overflow.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6639
6640<h5>Examples:</h5>
6641<pre>
6642 %res = call {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
6643 %sum = extractvalue {i32, i1} %res, 0
6644 %obit = extractvalue {i32, i1} %res, 1
6645 br i1 %obit, label %overflow, label %normal
6646</pre>
6647
6648</div>
6649
6650<!-- _______________________________________________________________________ -->
6651<div class="doc_subsubsection">
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]6652 <a name="int_smul_overflow">'<tt>llvm.smul.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6653</div>
6654
6655<div class="doc_text">
6656
6657<h5>Syntax:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6658<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]6659 on any integer bit width.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6660
6661<pre>
6662 declare {i16, i1} @llvm.smul.with.overflow.i16(i16 %a, i16 %b)
6663 declare {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
6664 declare {i64, i1} @llvm.smul.with.overflow.i64(i64 %a, i64 %b)
6665</pre>
6666
6667<h5>Overview:</h5>
6668
6669<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6670 a signed multiplication of the two arguments, and indicate whether an
6671 overflow occurred during the signed multiplication.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6672
6673<h5>Arguments:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6674<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]6675 be of integer types of any bit width, but they must have the same bit
6676 width. The second element of the result structure must be of
6677 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6678 undergo signed multiplication.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6679
6680<h5>Semantics:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6681<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6682 a signed multiplication of the two arguments. They return a structure &mdash;
6683 the first element of which is the multiplication, and the second element of
6684 which is a bit specifying if the signed multiplication resulted in an
6685 overflow.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6686
6687<h5>Examples:</h5>
6688<pre>
6689 %res = call {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
6690 %sum = extractvalue {i32, i1} %res, 0
6691 %obit = extractvalue {i32, i1} %res, 1
6692 br i1 %obit, label %overflow, label %normal
6693</pre>
6694
Reid Spencer5bf54c82007-04-11 23:23:49 +0000[diff] [blame]6695</div>
6696
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]6697<!-- _______________________________________________________________________ -->
6698<div class="doc_subsubsection">
6699 <a name="int_umul_overflow">'<tt>llvm.umul.with.overflow.*</tt>' Intrinsics</a>
6700</div>
6701
6702<div class="doc_text">
6703
6704<h5>Syntax:</h5>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]6705<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]6706 on any integer bit width.</p>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]6707
6708<pre>
6709 declare {i16, i1} @llvm.umul.with.overflow.i16(i16 %a, i16 %b)
6710 declare {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
6711 declare {i64, i1} @llvm.umul.with.overflow.i64(i64 %a, i64 %b)
6712</pre>
6713
6714<h5>Overview:</h5>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]6715<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6716 a unsigned multiplication of the two arguments, and indicate whether an
6717 overflow occurred during the unsigned multiplication.</p>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]6718
6719<h5>Arguments:</h5>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]6720<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]6721 be of integer types of any bit width, but they must have the same bit
6722 width. The second element of the result structure must be of
6723 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6724 undergo unsigned multiplication.</p>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]6725
6726<h5>Semantics:</h5>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]6727<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6728 an unsigned multiplication of the two arguments. They return a structure
6729 &mdash; the first element of which is the multiplication, and the second
6730 element of which is a bit specifying if the unsigned multiplication resulted
6731 in an overflow.</p>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]6732
6733<h5>Examples:</h5>
6734<pre>
6735 %res = call {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
6736 %sum = extractvalue {i32, i1} %res, 0
6737 %obit = extractvalue {i32, i1} %res, 1
6738 br i1 %obit, label %overflow, label %normal
6739</pre>
6740
6741</div>
6742
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]6743<!-- ======================================================================= -->
6744<div class="doc_subsection">
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]6745 <a name="int_fp16">Half Precision Floating Point Intrinsics</a>
6746</div>
6747
6748<div class="doc_text">
6749
Chris Lattner022a9fb2010-03-15 04:12:21 +0000[diff] [blame]6750<p>Half precision floating point is a storage-only format. This means that it is
6751 a dense encoding (in memory) but does not support computation in the
6752 format.</p>
Chris Lattnerbbd8bd32010-03-14 23:03:31 +0000[diff] [blame]6753
Chris Lattner022a9fb2010-03-15 04:12:21 +0000[diff] [blame]6754<p>This means that code must first load the half-precision floating point
Chris Lattnerbbd8bd32010-03-14 23:03:31 +0000[diff] [blame]6755 value as an i16, then convert it to float with <a
6756 href="#int_convert_from_fp16"><tt>llvm.convert.from.fp16</tt></a>.
6757 Computation can then be performed on the float value (including extending to
Chris Lattner022a9fb2010-03-15 04:12:21 +0000[diff] [blame]6758 double etc). To store the value back to memory, it is first converted to
6759 float if needed, then converted to i16 with
Chris Lattnerbbd8bd32010-03-14 23:03:31 +0000[diff] [blame]6760 <a href="#int_convert_to_fp16"><tt>llvm.convert.to.fp16</tt></a>, then
6761 storing as an i16 value.</p>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]6762</div>
6763
6764<!-- _______________________________________________________________________ -->
6765<div class="doc_subsubsection">
Chris Lattnerbbd8bd32010-03-14 23:03:31 +0000[diff] [blame]6766 <a name="int_convert_to_fp16">'<tt>llvm.convert.to.fp16</tt>' Intrinsic</a>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]6767</div>
6768
6769<div class="doc_text">
6770
6771<h5>Syntax:</h5>
6772<pre>
6773 declare i16 @llvm.convert.to.fp16(f32 %a)
6774</pre>
6775
6776<h5>Overview:</h5>
6777<p>The '<tt>llvm.convert.to.fp16</tt>' intrinsic function performs
6778 a conversion from single precision floating point format to half precision
6779 floating point format.</p>
6780
6781<h5>Arguments:</h5>
6782<p>The intrinsic function contains single argument - the value to be
6783 converted.</p>
6784
6785<h5>Semantics:</h5>
6786<p>The '<tt>llvm.convert.to.fp16</tt>' intrinsic function performs
6787 a conversion from single precision floating point format to half precision
Chris Lattner022a9fb2010-03-15 04:12:21 +0000[diff] [blame]6788 floating point format. The return value is an <tt>i16</tt> which
Chris Lattnerbbd8bd32010-03-14 23:03:31 +0000[diff] [blame]6789 contains the converted number.</p>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]6790
6791<h5>Examples:</h5>
6792<pre>
6793 %res = call i16 @llvm.convert.to.fp16(f32 %a)
6794 store i16 %res, i16* @x, align 2
6795</pre>
6796
6797</div>
6798
6799<!-- _______________________________________________________________________ -->
6800<div class="doc_subsubsection">
Chris Lattnerbbd8bd32010-03-14 23:03:31 +0000[diff] [blame]6801 <a name="int_convert_from_fp16">'<tt>llvm.convert.from.fp16</tt>' Intrinsic</a>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]6802</div>
6803
6804<div class="doc_text">
6805
6806<h5>Syntax:</h5>
6807<pre>
6808 declare f32 @llvm.convert.from.fp16(i16 %a)
6809</pre>
6810
6811<h5>Overview:</h5>
6812<p>The '<tt>llvm.convert.from.fp16</tt>' intrinsic function performs
6813 a conversion from half precision floating point format to single precision
6814 floating point format.</p>
6815
6816<h5>Arguments:</h5>
6817<p>The intrinsic function contains single argument - the value to be
6818 converted.</p>
6819
6820<h5>Semantics:</h5>
6821<p>The '<tt>llvm.convert.from.fp16</tt>' intrinsic function performs a
Chris Lattner022a9fb2010-03-15 04:12:21 +0000[diff] [blame]6822 conversion from half single precision floating point format to single
Chris Lattnerbbd8bd32010-03-14 23:03:31 +0000[diff] [blame]6823 precision floating point format. The input half-float value is represented by
6824 an <tt>i16</tt> value.</p>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]6825
6826<h5>Examples:</h5>
6827<pre>
6828 %a = load i16* @x, align 2
6829 %res = call f32 @llvm.convert.from.fp16(i16 %a)
6830</pre>
6831
6832</div>
6833
6834<!-- ======================================================================= -->
6835<div class="doc_subsection">
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]6836 <a name="int_debugger">Debugger Intrinsics</a>
6837</div>
6838
6839<div class="doc_text">
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]6840
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6841<p>The LLVM debugger intrinsics (which all start with <tt>llvm.dbg.</tt>
6842 prefix), are described in
6843 the <a href="SourceLevelDebugging.html#format_common_intrinsics">LLVM Source
6844 Level Debugging</a> document.</p>
6845
6846</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]6847
Jim Laskey2211f492007-03-14 19:31:19 +0000[diff] [blame]6848<!-- ======================================================================= -->
6849<div class="doc_subsection">
6850 <a name="int_eh">Exception Handling Intrinsics</a>
6851</div>
6852
6853<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6854
6855<p>The LLVM exception handling intrinsics (which all start with
6856 <tt>llvm.eh.</tt> prefix), are described in
6857 the <a href="ExceptionHandling.html#format_common_intrinsics">LLVM Exception
6858 Handling</a> document.</p>
6859
Jim Laskey2211f492007-03-14 19:31:19 +0000[diff] [blame]6860</div>
6861
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]6862<!-- ======================================================================= -->
6863<div class="doc_subsection">
Duncan Sands86e01192007-09-11 14:10:23 +0000[diff] [blame]6864 <a name="int_trampoline">Trampoline Intrinsic</a>
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]6865</div>
6866
6867<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6868
6869<p>This intrinsic makes it possible to excise one parameter, marked with
Dan Gohman3770af52010-07-02 23:18:08 +0000[diff] [blame]6870 the <a href="#nest"><tt>nest</tt></a> attribute, from a function.
6871 The result is a callable
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6872 function pointer lacking the nest parameter - the caller does not need to
6873 provide a value for it. Instead, the value to use is stored in advance in a
6874 "trampoline", a block of memory usually allocated on the stack, which also
6875 contains code to splice the nest value into the argument list. This is used
6876 to implement the GCC nested function address extension.</p>
6877
6878<p>For example, if the function is
6879 <tt>i32 f(i8* nest %c, i32 %x, i32 %y)</tt> then the resulting function
6880 pointer has signature <tt>i32 (i32, i32)*</tt>. It can be created as
6881 follows:</p>
6882
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]6883<pre class="doc_code">
Duncan Sands86e01192007-09-11 14:10:23 +0000[diff] [blame]6884 %tramp = alloca [10 x i8], align 4 ; size and alignment only correct for X86
6885 %tramp1 = getelementptr [10 x i8]* %tramp, i32 0, i32 0
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]6886 %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]6887 %fp = bitcast i8* %p to i32 (i32, i32)*
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]6888</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6889
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]6890<p>The call <tt>%val = call i32 %fp(i32 %x, i32 %y)</tt> is then equivalent
6891 to <tt>%val = call i32 %f(i8* %nval, i32 %x, i32 %y)</tt>.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6892
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]6893</div>
6894
6895<!-- _______________________________________________________________________ -->
6896<div class="doc_subsubsection">
6897 <a name="int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a>
6898</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6899
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]6900<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6901
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]6902<h5>Syntax:</h5>
6903<pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6904 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]6905</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6906
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]6907<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6908<p>This fills the memory pointed to by <tt>tramp</tt> with code and returns a
6909 function pointer suitable for executing it.</p>
6910
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]6911<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6912<p>The <tt>llvm.init.trampoline</tt> intrinsic takes three arguments, all
6913 pointers. The <tt>tramp</tt> argument must point to a sufficiently large and
6914 sufficiently aligned block of memory; this memory is written to by the
6915 intrinsic. Note that the size and the alignment are target-specific - LLVM
6916 currently provides no portable way of determining them, so a front-end that
6917 generates this intrinsic needs to have some target-specific knowledge.
6918 The <tt>func</tt> argument must hold a function bitcast to
6919 an <tt>i8*</tt>.</p>
6920
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]6921<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6922<p>The block of memory pointed to by <tt>tramp</tt> is filled with target
6923 dependent code, turning it into a function. A pointer to this function is
6924 returned, but needs to be bitcast to an <a href="#int_trampoline">appropriate
6925 function pointer type</a> before being called. The new function's signature
6926 is the same as that of <tt>func</tt> with any arguments marked with
6927 the <tt>nest</tt> attribute removed. At most one such <tt>nest</tt> argument
6928 is allowed, and it must be of pointer type. Calling the new function is
6929 equivalent to calling <tt>func</tt> with the same argument list, but
6930 with <tt>nval</tt> used for the missing <tt>nest</tt> argument. If, after
6931 calling <tt>llvm.init.trampoline</tt>, the memory pointed to
6932 by <tt>tramp</tt> is modified, then the effect of any later call to the
6933 returned function pointer is undefined.</p>
6934
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]6935</div>
6936
6937<!-- ======================================================================= -->
6938<div class="doc_subsection">
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]6939 <a name="int_atomics">Atomic Operations and Synchronization Intrinsics</a>
6940</div>
6941
6942<div class="doc_text">
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]6943
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6944<p>These intrinsic functions expand the "universal IR" of LLVM to represent
6945 hardware constructs for atomic operations and memory synchronization. This
6946 provides an interface to the hardware, not an interface to the programmer. It
6947 is aimed at a low enough level to allow any programming models or APIs
6948 (Application Programming Interfaces) which need atomic behaviors to map
6949 cleanly onto it. It is also modeled primarily on hardware behavior. Just as
6950 hardware provides a "universal IR" for source languages, it also provides a
6951 starting point for developing a "universal" atomic operation and
6952 synchronization IR.</p>
6953
6954<p>These do <em>not</em> form an API such as high-level threading libraries,
6955 software transaction memory systems, atomic primitives, and intrinsic
6956 functions as found in BSD, GNU libc, atomic_ops, APR, and other system and
6957 application libraries. The hardware interface provided by LLVM should allow
6958 a clean implementation of all of these APIs and parallel programming models.
6959 No one model or paradigm should be selected above others unless the hardware
6960 itself ubiquitously does so.</p>
6961
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]6962</div>
6963
6964<!-- _______________________________________________________________________ -->
6965<div class="doc_subsubsection">
6966 <a name="int_memory_barrier">'<tt>llvm.memory.barrier</tt>' Intrinsic</a>
6967</div>
6968<div class="doc_text">
6969<h5>Syntax:</h5>
6970<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]6971 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]6972</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6973
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]6974<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6975<p>The <tt>llvm.memory.barrier</tt> intrinsic guarantees ordering between
6976 specific pairs of memory access types.</p>
6977
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]6978<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6979<p>The <tt>llvm.memory.barrier</tt> intrinsic requires five boolean arguments.
6980 The first four arguments enables a specific barrier as listed below. The
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]6981 fifth argument specifies that the barrier applies to io or device or uncached
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6982 memory.</p>
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]6983
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6984<ul>
6985 <li><tt>ll</tt>: load-load barrier</li>
6986 <li><tt>ls</tt>: load-store barrier</li>
6987 <li><tt>sl</tt>: store-load barrier</li>
6988 <li><tt>ss</tt>: store-store barrier</li>
6989 <li><tt>device</tt>: barrier applies to device and uncached memory also.</li>
6990</ul>
6991
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]6992<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6993<p>This intrinsic causes the system to enforce some ordering constraints upon
6994 the loads and stores of the program. This barrier does not
6995 indicate <em>when</em> any events will occur, it only enforces
6996 an <em>order</em> in which they occur. For any of the specified pairs of load
6997 and store operations (f.ex. load-load, or store-load), all of the first
6998 operations preceding the barrier will complete before any of the second
6999 operations succeeding the barrier begin. Specifically the semantics for each
7000 pairing is as follows:</p>
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7001
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7002<ul>
7003 <li><tt>ll</tt>: All loads before the barrier must complete before any load
7004 after the barrier begins.</li>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]7005 <li><tt>ls</tt>: All loads before the barrier must complete before any
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7006 store after the barrier begins.</li>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]7007 <li><tt>ss</tt>: All stores before the barrier must complete before any
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7008 store after the barrier begins.</li>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]7009 <li><tt>sl</tt>: All stores before the barrier must complete before any
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7010 load after the barrier begins.</li>
7011</ul>
7012
7013<p>These semantics are applied with a logical "and" behavior when more than one
7014 is enabled in a single memory barrier intrinsic.</p>
7015
7016<p>Backends may implement stronger barriers than those requested when they do
7017 not support as fine grained a barrier as requested. Some architectures do
7018 not need all types of barriers and on such architectures, these become
7019 noops.</p>
7020
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7021<h5>Example:</h5>
7022<pre>
Victor Hernandeza70c6df2009-10-26 23:44:29 +0000[diff] [blame]7023%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7024%ptr = bitcast i8* %mallocP to i32*
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7025 store i32 4, %ptr
7026
7027%result1 = load i32* %ptr <i>; yields {i32}:result1 = 4</i>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7028 call void @llvm.memory.barrier(i1 false, i1 true, i1 false, i1 false)
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7029 <i>; guarantee the above finishes</i>
7030 store i32 8, %ptr <i>; before this begins</i>
7031</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7032
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7033</div>
7034
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7035<!-- _______________________________________________________________________ -->
7036<div class="doc_subsubsection">
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7037 <a name="int_atomic_cmp_swap">'<tt>llvm.atomic.cmp.swap.*</tt>' Intrinsic</a>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7038</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7039
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7040<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7041
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7042<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7043<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.cmp.swap</tt> on
7044 any integer bit width and for different address spaces. Not all targets
7045 support all bit widths however.</p>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7046
7047<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7048 declare i8 @llvm.atomic.cmp.swap.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;cmp&gt;, i8 &lt;val&gt;)
7049 declare i16 @llvm.atomic.cmp.swap.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;cmp&gt;, i16 &lt;val&gt;)
7050 declare i32 @llvm.atomic.cmp.swap.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;cmp&gt;, i32 &lt;val&gt;)
7051 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]7052</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7053
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7054<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7055<p>This loads a value in memory and compares it to a given value. If they are
7056 equal, it stores a new value into the memory.</p>
7057
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7058<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7059<p>The <tt>llvm.atomic.cmp.swap</tt> intrinsic takes three arguments. The result
7060 as well as both <tt>cmp</tt> and <tt>val</tt> must be integer values with the
7061 same bit width. The <tt>ptr</tt> argument must be a pointer to a value of
7062 this integer type. While any bit width integer may be used, targets may only
7063 lower representations they support in hardware.</p>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7064
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7065<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7066<p>This entire intrinsic must be executed atomically. It first loads the value
7067 in memory pointed to by <tt>ptr</tt> and compares it with the
7068 value <tt>cmp</tt>. If they are equal, <tt>val</tt> is stored into the
7069 memory. The loaded value is yielded in all cases. This provides the
7070 equivalent of an atomic compare-and-swap operation within the SSA
7071 framework.</p>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7072
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7073<h5>Examples:</h5>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7074<pre>
Victor Hernandeza70c6df2009-10-26 23:44:29 +0000[diff] [blame]7075%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7076%ptr = bitcast i8* %mallocP to i32*
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7077 store i32 4, %ptr
7078
7079%val1 = add i32 4, 4
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7080%result1 = call i32 @llvm.atomic.cmp.swap.i32.p0i32(i32* %ptr, i32 4, %val1)
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7081 <i>; yields {i32}:result1 = 4</i>
7082%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
7083%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
7084
7085%val2 = add i32 1, 1
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7086%result2 = call i32 @llvm.atomic.cmp.swap.i32.p0i32(i32* %ptr, i32 5, %val2)
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7087 <i>; yields {i32}:result2 = 8</i>
7088%stored2 = icmp eq i32 %result2, 5 <i>; yields {i1}:stored2 = false</i>
7089
7090%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 8</i>
7091</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7092
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7093</div>
7094
7095<!-- _______________________________________________________________________ -->
7096<div class="doc_subsubsection">
7097 <a name="int_atomic_swap">'<tt>llvm.atomic.swap.*</tt>' Intrinsic</a>
7098</div>
7099<div class="doc_text">
7100<h5>Syntax:</h5>
7101
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7102<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.swap</tt> on any
7103 integer bit width. Not all targets support all bit widths however.</p>
7104
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7105<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7106 declare i8 @llvm.atomic.swap.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;val&gt;)
7107 declare i16 @llvm.atomic.swap.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;val&gt;)
7108 declare i32 @llvm.atomic.swap.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;val&gt;)
7109 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]7110</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7111
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7112<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7113<p>This intrinsic loads the value stored in memory at <tt>ptr</tt> and yields
7114 the value from memory. It then stores the value in <tt>val</tt> in the memory
7115 at <tt>ptr</tt>.</p>
7116
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7117<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7118<p>The <tt>llvm.atomic.swap</tt> intrinsic takes two arguments. Both
7119 the <tt>val</tt> argument and the result must be integers of the same bit
7120 width. The first argument, <tt>ptr</tt>, must be a pointer to a value of this
7121 integer type. The targets may only lower integer representations they
7122 support.</p>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7123
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7124<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7125<p>This intrinsic loads the value pointed to by <tt>ptr</tt>, yields it, and
7126 stores <tt>val</tt> back into <tt>ptr</tt> atomically. This provides the
7127 equivalent of an atomic swap operation within the SSA framework.</p>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7128
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7129<h5>Examples:</h5>
7130<pre>
Victor Hernandeza70c6df2009-10-26 23:44:29 +0000[diff] [blame]7131%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7132%ptr = bitcast i8* %mallocP to i32*
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7133 store i32 4, %ptr
7134
7135%val1 = add i32 4, 4
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7136%result1 = call i32 @llvm.atomic.swap.i32.p0i32(i32* %ptr, i32 %val1)
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7137 <i>; yields {i32}:result1 = 4</i>
7138%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
7139%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
7140
7141%val2 = add i32 1, 1
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7142%result2 = call i32 @llvm.atomic.swap.i32.p0i32(i32* %ptr, i32 %val2)
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7143 <i>; yields {i32}:result2 = 8</i>
7144
7145%stored2 = icmp eq i32 %result2, 8 <i>; yields {i1}:stored2 = true</i>
7146%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 2</i>
7147</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7148
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7149</div>
7150
7151<!-- _______________________________________________________________________ -->
7152<div class="doc_subsubsection">
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7153 <a name="int_atomic_load_add">'<tt>llvm.atomic.load.add.*</tt>' Intrinsic</a>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7154
7155</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7156
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7157<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7158
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7159<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7160<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.load.add</tt> on
7161 any integer bit width. Not all targets support all bit widths however.</p>
7162
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7163<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7164 declare i8 @llvm.atomic.load.add.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7165 declare i16 @llvm.atomic.load.add.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7166 declare i32 @llvm.atomic.load.add.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7167 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]7168</pre>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7169
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7170<h5>Overview:</h5>
7171<p>This intrinsic adds <tt>delta</tt> to the value stored in memory
7172 at <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.</p>
7173
7174<h5>Arguments:</h5>
7175<p>The intrinsic takes two arguments, the first a pointer to an integer value
7176 and the second an integer value. The result is also an integer value. These
7177 integer types can have any bit width, but they must all have the same bit
7178 width. The targets may only lower integer representations they support.</p>
7179
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7180<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7181<p>This intrinsic does a series of operations atomically. It first loads the
7182 value stored at <tt>ptr</tt>. It then adds <tt>delta</tt>, stores the result
7183 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]7184
7185<h5>Examples:</h5>
7186<pre>
Victor Hernandeza70c6df2009-10-26 23:44:29 +0000[diff] [blame]7187%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7188%ptr = bitcast i8* %mallocP to i32*
7189 store i32 4, %ptr
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7190%result1 = call i32 @llvm.atomic.load.add.i32.p0i32(i32* %ptr, i32 4)
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7191 <i>; yields {i32}:result1 = 4</i>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7192%result2 = call i32 @llvm.atomic.load.add.i32.p0i32(i32* %ptr, i32 2)
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7193 <i>; yields {i32}:result2 = 8</i>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7194%result3 = call i32 @llvm.atomic.load.add.i32.p0i32(i32* %ptr, i32 5)
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7195 <i>; yields {i32}:result3 = 10</i>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7196%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 15</i>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7197</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7198
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7199</div>
7200
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7201<!-- _______________________________________________________________________ -->
7202<div class="doc_subsubsection">
7203 <a name="int_atomic_load_sub">'<tt>llvm.atomic.load.sub.*</tt>' Intrinsic</a>
7204
7205</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7206
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7207<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7208
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7209<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7210<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.load.sub</tt> on
7211 any integer bit width and for different address spaces. Not all targets
7212 support all bit widths however.</p>
7213
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7214<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7215 declare i8 @llvm.atomic.load.sub.i8.p0i32(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7216 declare i16 @llvm.atomic.load.sub.i16.p0i32(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7217 declare i32 @llvm.atomic.load.sub.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7218 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]7219</pre>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7220
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7221<h5>Overview:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]7222<p>This intrinsic subtracts <tt>delta</tt> to the value stored in memory at
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7223 <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.</p>
7224
7225<h5>Arguments:</h5>
7226<p>The intrinsic takes two arguments, the first a pointer to an integer value
7227 and the second an integer value. The result is also an integer value. These
7228 integer types can have any bit width, but they must all have the same bit
7229 width. The targets may only lower integer representations they support.</p>
7230
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7231<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7232<p>This intrinsic does a series of operations atomically. It first loads the
7233 value stored at <tt>ptr</tt>. It then subtracts <tt>delta</tt>, stores the
7234 result to <tt>ptr</tt>. It yields the original value stored
7235 at <tt>ptr</tt>.</p>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7236
7237<h5>Examples:</h5>
7238<pre>
Victor Hernandeza70c6df2009-10-26 23:44:29 +0000[diff] [blame]7239%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7240%ptr = bitcast i8* %mallocP to i32*
7241 store i32 8, %ptr
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7242%result1 = call i32 @llvm.atomic.load.sub.i32.p0i32(i32* %ptr, i32 4)
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7243 <i>; yields {i32}:result1 = 8</i>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7244%result2 = call i32 @llvm.atomic.load.sub.i32.p0i32(i32* %ptr, i32 2)
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7245 <i>; yields {i32}:result2 = 4</i>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7246%result3 = call i32 @llvm.atomic.load.sub.i32.p0i32(i32* %ptr, i32 5)
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7247 <i>; yields {i32}:result3 = 2</i>
7248%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = -3</i>
7249</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7250
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7251</div>
7252
7253<!-- _______________________________________________________________________ -->
7254<div class="doc_subsubsection">
7255 <a name="int_atomic_load_and">'<tt>llvm.atomic.load.and.*</tt>' Intrinsic</a><br>
7256 <a name="int_atomic_load_nand">'<tt>llvm.atomic.load.nand.*</tt>' Intrinsic</a><br>
7257 <a name="int_atomic_load_or">'<tt>llvm.atomic.load.or.*</tt>' Intrinsic</a><br>
7258 <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]7259</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7260
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7261<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7262
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7263<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7264<p>These are overloaded intrinsics. You can
7265 use <tt>llvm.atomic.load_and</tt>, <tt>llvm.atomic.load_nand</tt>,
7266 <tt>llvm.atomic.load_or</tt>, and <tt>llvm.atomic.load_xor</tt> on any integer
7267 bit width and for different address spaces. Not all targets support all bit
7268 widths however.</p>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7269
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7270<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7271 declare i8 @llvm.atomic.load.and.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7272 declare i16 @llvm.atomic.load.and.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7273 declare i32 @llvm.atomic.load.and.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7274 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]7275</pre>
7276
7277<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7278 declare i8 @llvm.atomic.load.or.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7279 declare i16 @llvm.atomic.load.or.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7280 declare i32 @llvm.atomic.load.or.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7281 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]7282</pre>
7283
7284<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7285 declare i8 @llvm.atomic.load.nand.i8.p0i32(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7286 declare i16 @llvm.atomic.load.nand.i16.p0i32(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7287 declare i32 @llvm.atomic.load.nand.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7288 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]7289</pre>
7290
7291<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7292 declare i8 @llvm.atomic.load.xor.i8.p0i32(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7293 declare i16 @llvm.atomic.load.xor.i16.p0i32(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7294 declare i32 @llvm.atomic.load.xor.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7295 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]7296</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7297
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7298<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7299<p>These intrinsics bitwise the operation (and, nand, or, xor) <tt>delta</tt> to
7300 the value stored in memory at <tt>ptr</tt>. It yields the original value
7301 at <tt>ptr</tt>.</p>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7302
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7303<h5>Arguments:</h5>
7304<p>These intrinsics take two arguments, the first a pointer to an integer value
7305 and the second an integer value. The result is also an integer value. These
7306 integer types can have any bit width, but they must all have the same bit
7307 width. The targets may only lower integer representations they support.</p>
7308
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7309<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7310<p>These intrinsics does a series of operations atomically. They first load the
7311 value stored at <tt>ptr</tt>. They then do the bitwise
7312 operation <tt>delta</tt>, store the result to <tt>ptr</tt>. They yield the
7313 original value stored at <tt>ptr</tt>.</p>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7314
7315<h5>Examples:</h5>
7316<pre>
Victor Hernandeza70c6df2009-10-26 23:44:29 +0000[diff] [blame]7317%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7318%ptr = bitcast i8* %mallocP to i32*
7319 store i32 0x0F0F, %ptr
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7320%result0 = call i32 @llvm.atomic.load.nand.i32.p0i32(i32* %ptr, i32 0xFF)
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7321 <i>; yields {i32}:result0 = 0x0F0F</i>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7322%result1 = call i32 @llvm.atomic.load.and.i32.p0i32(i32* %ptr, i32 0xFF)
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7323 <i>; yields {i32}:result1 = 0xFFFFFFF0</i>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7324%result2 = call i32 @llvm.atomic.load.or.i32.p0i32(i32* %ptr, i32 0F)
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7325 <i>; yields {i32}:result2 = 0xF0</i>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7326%result3 = call i32 @llvm.atomic.load.xor.i32.p0i32(i32* %ptr, i32 0F)
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7327 <i>; yields {i32}:result3 = FF</i>
7328%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = F0</i>
7329</pre>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7330
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7331</div>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7332
7333<!-- _______________________________________________________________________ -->
7334<div class="doc_subsubsection">
7335 <a name="int_atomic_load_max">'<tt>llvm.atomic.load.max.*</tt>' Intrinsic</a><br>
7336 <a name="int_atomic_load_min">'<tt>llvm.atomic.load.min.*</tt>' Intrinsic</a><br>
7337 <a name="int_atomic_load_umax">'<tt>llvm.atomic.load.umax.*</tt>' Intrinsic</a><br>
7338 <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]7339</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7340
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7341<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7342
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7343<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7344<p>These are overloaded intrinsics. You can use <tt>llvm.atomic.load_max</tt>,
7345 <tt>llvm.atomic.load_min</tt>, <tt>llvm.atomic.load_umax</tt>, and
7346 <tt>llvm.atomic.load_umin</tt> on any integer bit width and for different
7347 address spaces. Not all targets support all bit widths however.</p>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7348
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7349<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7350 declare i8 @llvm.atomic.load.max.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7351 declare i16 @llvm.atomic.load.max.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7352 declare i32 @llvm.atomic.load.max.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7353 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]7354</pre>
7355
7356<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7357 declare i8 @llvm.atomic.load.min.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7358 declare i16 @llvm.atomic.load.min.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7359 declare i32 @llvm.atomic.load.min.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7360 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]7361</pre>
7362
7363<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7364 declare i8 @llvm.atomic.load.umax.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7365 declare i16 @llvm.atomic.load.umax.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7366 declare i32 @llvm.atomic.load.umax.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7367 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]7368</pre>
7369
7370<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7371 declare i8 @llvm.atomic.load.umin.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7372 declare i16 @llvm.atomic.load.umin.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7373 declare i32 @llvm.atomic.load.umin.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7374 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]7375</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7376
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7377<h5>Overview:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]7378<p>These intrinsics takes the signed or unsigned minimum or maximum of
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7379 <tt>delta</tt> and the value stored in memory at <tt>ptr</tt>. It yields the
7380 original value at <tt>ptr</tt>.</p>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7381
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7382<h5>Arguments:</h5>
7383<p>These intrinsics take two arguments, the first a pointer to an integer value
7384 and the second an integer value. The result is also an integer value. These
7385 integer types can have any bit width, but they must all have the same bit
7386 width. The targets may only lower integer representations they support.</p>
7387
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7388<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7389<p>These intrinsics does a series of operations atomically. They first load the
7390 value stored at <tt>ptr</tt>. They then do the signed or unsigned min or
7391 max <tt>delta</tt> and the value, store the result to <tt>ptr</tt>. They
7392 yield the original value stored at <tt>ptr</tt>.</p>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7393
7394<h5>Examples:</h5>
7395<pre>
Victor Hernandeza70c6df2009-10-26 23:44:29 +0000[diff] [blame]7396%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7397%ptr = bitcast i8* %mallocP to i32*
7398 store i32 7, %ptr
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7399%result0 = call i32 @llvm.atomic.load.min.i32.p0i32(i32* %ptr, i32 -2)
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7400 <i>; yields {i32}:result0 = 7</i>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7401%result1 = call i32 @llvm.atomic.load.max.i32.p0i32(i32* %ptr, i32 8)
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7402 <i>; yields {i32}:result1 = -2</i>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7403%result2 = call i32 @llvm.atomic.load.umin.i32.p0i32(i32* %ptr, i32 10)
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7404 <i>; yields {i32}:result2 = 8</i>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7405%result3 = call i32 @llvm.atomic.load.umax.i32.p0i32(i32* %ptr, i32 30)
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7406 <i>; yields {i32}:result3 = 8</i>
7407%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 30</i>
7408</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7409
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7410</div>
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7411
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]7412
7413<!-- ======================================================================= -->
7414<div class="doc_subsection">
7415 <a name="int_memorymarkers">Memory Use Markers</a>
7416</div>
7417
7418<div class="doc_text">
7419
7420<p>This class of intrinsics exists to information about the lifetime of memory
7421 objects and ranges where variables are immutable.</p>
7422
7423</div>
7424
7425<!-- _______________________________________________________________________ -->
7426<div class="doc_subsubsection">
7427 <a name="int_lifetime_start">'<tt>llvm.lifetime.start</tt>' Intrinsic</a>
7428</div>
7429
7430<div class="doc_text">
7431
7432<h5>Syntax:</h5>
7433<pre>
7434 declare void @llvm.lifetime.start(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7435</pre>
7436
7437<h5>Overview:</h5>
7438<p>The '<tt>llvm.lifetime.start</tt>' intrinsic specifies the start of a memory
7439 object's lifetime.</p>
7440
7441<h5>Arguments:</h5>
Nick Lewycky9bc89042009-10-13 07:57:33 +0000[diff] [blame]7442<p>The first argument is a constant integer representing the size of the
7443 object, or -1 if it is variable sized. The second argument is a pointer to
7444 the object.</p>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]7445
7446<h5>Semantics:</h5>
7447<p>This intrinsic indicates that before this point in the code, the value of the
7448 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]7449 never be used and has an undefined value. A load from the pointer that
7450 precedes this intrinsic can be replaced with
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]7451 <tt>'<a href="#undefvalues">undef</a>'</tt>.</p>
7452
7453</div>
7454
7455<!-- _______________________________________________________________________ -->
7456<div class="doc_subsubsection">
7457 <a name="int_lifetime_end">'<tt>llvm.lifetime.end</tt>' Intrinsic</a>
7458</div>
7459
7460<div class="doc_text">
7461
7462<h5>Syntax:</h5>
7463<pre>
7464 declare void @llvm.lifetime.end(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7465</pre>
7466
7467<h5>Overview:</h5>
7468<p>The '<tt>llvm.lifetime.end</tt>' intrinsic specifies the end of a memory
7469 object's lifetime.</p>
7470
7471<h5>Arguments:</h5>
Nick Lewycky9bc89042009-10-13 07:57:33 +0000[diff] [blame]7472<p>The first argument is a constant integer representing the size of the
7473 object, or -1 if it is variable sized. The second argument is a pointer to
7474 the object.</p>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]7475
7476<h5>Semantics:</h5>
7477<p>This intrinsic indicates that after this point in the code, the value of the
7478 memory pointed to by <tt>ptr</tt> is dead. This means that it is known to
7479 never be used and has an undefined value. Any stores into the memory object
7480 following this intrinsic may be removed as dead.
7481
7482</div>
7483
7484<!-- _______________________________________________________________________ -->
7485<div class="doc_subsubsection">
7486 <a name="int_invariant_start">'<tt>llvm.invariant.start</tt>' Intrinsic</a>
7487</div>
7488
7489<div class="doc_text">
7490
7491<h5>Syntax:</h5>
7492<pre>
7493 declare {}* @llvm.invariant.start(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;) readonly
7494</pre>
7495
7496<h5>Overview:</h5>
7497<p>The '<tt>llvm.invariant.start</tt>' intrinsic specifies that the contents of
7498 a memory object will not change.</p>
7499
7500<h5>Arguments:</h5>
Nick Lewycky9bc89042009-10-13 07:57:33 +0000[diff] [blame]7501<p>The first argument is a constant integer representing the size of the
7502 object, or -1 if it is variable sized. The second argument is a pointer to
7503 the object.</p>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]7504
7505<h5>Semantics:</h5>
7506<p>This intrinsic indicates that until an <tt>llvm.invariant.end</tt> that uses
7507 the return value, the referenced memory location is constant and
7508 unchanging.</p>
7509
7510</div>
7511
7512<!-- _______________________________________________________________________ -->
7513<div class="doc_subsubsection">
7514 <a name="int_invariant_end">'<tt>llvm.invariant.end</tt>' Intrinsic</a>
7515</div>
7516
7517<div class="doc_text">
7518
7519<h5>Syntax:</h5>
7520<pre>
7521 declare void @llvm.invariant.end({}* &lt;start&gt;, i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7522</pre>
7523
7524<h5>Overview:</h5>
7525<p>The '<tt>llvm.invariant.end</tt>' intrinsic specifies that the contents of
7526 a memory object are mutable.</p>
7527
7528<h5>Arguments:</h5>
7529<p>The first argument is the matching <tt>llvm.invariant.start</tt> intrinsic.
Nick Lewycky9bc89042009-10-13 07:57:33 +0000[diff] [blame]7530 The second argument is a constant integer representing the size of the
7531 object, or -1 if it is variable sized and the third argument is a pointer
7532 to the object.</p>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]7533
7534<h5>Semantics:</h5>
7535<p>This intrinsic indicates that the memory is mutable again.</p>
7536
7537</div>
7538
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7539<!-- ======================================================================= -->
7540<div class="doc_subsection">
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]7541 <a name="int_general">General Intrinsics</a>
7542</div>
7543
7544<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7545
7546<p>This class of intrinsics is designed to be generic and has no specific
7547 purpose.</p>
7548
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]7549</div>
7550
7551<!-- _______________________________________________________________________ -->
7552<div class="doc_subsubsection">
7553 <a name="int_var_annotation">'<tt>llvm.var.annotation</tt>' Intrinsic</a>
7554</div>
7555
7556<div class="doc_text">
7557
7558<h5>Syntax:</h5>
7559<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7560 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]7561</pre>
7562
7563<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7564<p>The '<tt>llvm.var.annotation</tt>' intrinsic.</p>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]7565
7566<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7567<p>The first argument is a pointer to a value, the second is a pointer to a
7568 global string, the third is a pointer to a global string which is the source
7569 file name, and the last argument is the line number.</p>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]7570
7571<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7572<p>This intrinsic allows annotation of local variables with arbitrary strings.
7573 This can be useful for special purpose optimizations that want to look for
7574 these annotations. These have no other defined use, they are ignored by code
7575 generation and optimization.</p>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]7576
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]7577</div>
7578
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]7579<!-- _______________________________________________________________________ -->
7580<div class="doc_subsubsection">
Tanya Lattner0186a652007-09-21 23:57:59 +0000[diff] [blame]7581 <a name="int_annotation">'<tt>llvm.annotation.*</tt>' Intrinsic</a>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]7582</div>
7583
7584<div class="doc_text">
7585
7586<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7587<p>This is an overloaded intrinsic. You can use '<tt>llvm.annotation</tt>' on
7588 any integer bit width.</p>
7589
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]7590<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7591 declare i8 @llvm.annotation.i8(i8 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
7592 declare i16 @llvm.annotation.i16(i16 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
7593 declare i32 @llvm.annotation.i32(i32 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
7594 declare i64 @llvm.annotation.i64(i64 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
7595 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]7596</pre>
7597
7598<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7599<p>The '<tt>llvm.annotation</tt>' intrinsic.</p>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]7600
7601<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7602<p>The first argument is an integer value (result of some expression), the
7603 second is a pointer to a global string, the third is a pointer to a global
7604 string which is the source file name, and the last argument is the line
7605 number. It returns the value of the first argument.</p>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]7606
7607<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7608<p>This intrinsic allows annotations to be put on arbitrary expressions with
7609 arbitrary strings. This can be useful for special purpose optimizations that
7610 want to look for these annotations. These have no other defined use, they
7611 are ignored by code generation and optimization.</p>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]7612
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]7613</div>
Jim Laskey2211f492007-03-14 19:31:19 +0000[diff] [blame]7614
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]7615<!-- _______________________________________________________________________ -->
7616<div class="doc_subsubsection">
7617 <a name="int_trap">'<tt>llvm.trap</tt>' Intrinsic</a>
7618</div>
7619
7620<div class="doc_text">
7621
7622<h5>Syntax:</h5>
7623<pre>
7624 declare void @llvm.trap()
7625</pre>
7626
7627<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7628<p>The '<tt>llvm.trap</tt>' intrinsic.</p>
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]7629
7630<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7631<p>None.</p>
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]7632
7633<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7634<p>This intrinsics is lowered to the target dependent trap instruction. If the
7635 target does not have a trap instruction, this intrinsic will be lowered to
7636 the call of the <tt>abort()</tt> function.</p>
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]7637
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]7638</div>
7639
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]7640<!-- _______________________________________________________________________ -->
7641<div class="doc_subsubsection">
Misha Brukman50de2b22008-11-22 23:55:29 +0000[diff] [blame]7642 <a name="int_stackprotector">'<tt>llvm.stackprotector</tt>' Intrinsic</a>
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]7643</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7644
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]7645<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7646
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]7647<h5>Syntax:</h5>
7648<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7649 declare void @llvm.stackprotector(i8* &lt;guard&gt;, i8** &lt;slot&gt;)
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]7650</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7651
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]7652<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7653<p>The <tt>llvm.stackprotector</tt> intrinsic takes the <tt>guard</tt> and
7654 stores it onto the stack at <tt>slot</tt>. The stack slot is adjusted to
7655 ensure that it is placed on the stack before local variables.</p>
7656
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]7657<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7658<p>The <tt>llvm.stackprotector</tt> intrinsic requires two pointer
7659 arguments. The first argument is the value loaded from the stack
7660 guard <tt>@__stack_chk_guard</tt>. The second variable is an <tt>alloca</tt>
7661 that has enough space to hold the value of the guard.</p>
7662
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]7663<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7664<p>This intrinsic causes the prologue/epilogue inserter to force the position of
7665 the <tt>AllocaInst</tt> stack slot to be before local variables on the
7666 stack. This is to ensure that if a local variable on the stack is
7667 overwritten, it will destroy the value of the guard. When the function exits,
7668 the guard on the stack is checked against the original guard. If they're
7669 different, then the program aborts by calling the <tt>__stack_chk_fail()</tt>
7670 function.</p>
7671
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]7672</div>
7673
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]7674<!-- _______________________________________________________________________ -->
7675<div class="doc_subsubsection">
7676 <a name="int_objectsize">'<tt>llvm.objectsize</tt>' Intrinsic</a>
7677</div>
7678
7679<div class="doc_text">
7680
7681<h5>Syntax:</h5>
7682<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7683 declare i32 @llvm.objectsize.i32(i8* &lt;object&gt;, i1 &lt;type&gt;)
7684 declare i64 @llvm.objectsize.i64(i8* &lt;object&gt;, i1 &lt;type&gt;)
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]7685</pre>
7686
7687<h5>Overview:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]7688<p>The <tt>llvm.objectsize</tt> intrinsic is designed to provide information
Eric Christopher3070e162010-01-08 21:42:39 +0000[diff] [blame]7689 to the optimizers to discover at compile time either a) when an
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]7690 operation like memcpy will either overflow a buffer that corresponds to
7691 an object, or b) to determine that a runtime check for overflow isn't
7692 necessary. An object in this context means an allocation of a
Eric Christopher31e39bd2009-12-23 00:29:49 +0000[diff] [blame]7693 specific class, structure, array, or other object.</p>
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]7694
7695<h5>Arguments:</h5>
7696<p>The <tt>llvm.objectsize</tt> intrinsic takes two arguments. The first
Eric Christopher31e39bd2009-12-23 00:29:49 +0000[diff] [blame]7697 argument is a pointer to or into the <tt>object</tt>. The second argument
7698 is a boolean 0 or 1. This argument determines whether you want the
7699 maximum (0) or minimum (1) bytes remaining. This needs to be a literal 0 or
7700 1, variables are not allowed.</p>
7701
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]7702<h5>Semantics:</h5>
7703<p>The <tt>llvm.objectsize</tt> intrinsic is lowered to either a constant
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]7704 representing the size of the object concerned or <tt>i32/i64 -1 or 0</tt>
7705 (depending on the <tt>type</tt> argument if the size cannot be determined
7706 at compile time.</p>
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]7707
7708</div>
7709
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]7710<!-- *********************************************************************** -->
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]7711<hr>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]7712<address>
7713 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
Misha Brukman86242e12008-12-11 17:34:48 +0000[diff] [blame]7714 src="http://jigsaw.w3.org/css-validator/images/vcss-blue" alt="Valid CSS"></a>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]7715 <a href="http://validator.w3.org/check/referer"><img
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Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]7717
7718 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
Reid Spencerca058542006-03-14 05:39:39 +0000[diff] [blame]7719 <a href="http://llvm.org">The LLVM Compiler Infrastructure</a><br>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]7720 Last modified: $Date$
7721</address>
Chris Lattnerb8f816e2008-01-04 04:33:49 +0000[diff] [blame]7722
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]7723</body>
7724</html>