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gerrit-public.fairphone.software / toolchain / llvm-project / 03bcd6ecc8e71af76a3ca1277adb4c2440265893 / . / 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 Wendling8693ef82009-07-20 02:41:50 +0000[diff] [blame]28 <li><a href="#linkage_internal">'<tt>internal</tt>' Linkage</a></li>
29 <li><a href="#linkage_available_externally">'<tt>available_externally</tt>' Linkage</a></li>
30 <li><a href="#linkage_linkonce">'<tt>linkonce</tt>' Linkage</a></li>
31 <li><a href="#linkage_common">'<tt>common</tt>' Linkage</a></li>
32 <li><a href="#linkage_weak">'<tt>weak</tt>' Linkage</a></li>
33 <li><a href="#linkage_appending">'<tt>appending</tt>' Linkage</a></li>
34 <li><a href="#linkage_externweak">'<tt>extern_weak</tt>' Linkage</a></li>
Chris Lattner80d73c72009-10-10 18:26:06 +0000[diff] [blame]35 <li><a href="#linkage_linkonce_odr">'<tt>linkonce_odr</tt>' Linkage</a></li>
Bill Wendling8693ef82009-07-20 02:41:50 +0000[diff] [blame]36 <li><a href="#linkage_weak">'<tt>weak_odr</tt>' Linkage</a></li>
37 <li><a href="#linkage_external">'<tt>externally visible</tt>' Linkage</a></li>
38 <li><a href="#linkage_dllimport">'<tt>dllimport</tt>' Linkage</a></li>
39 <li><a href="#linkage_dllexport">'<tt>dllexport</tt>' Linkage</a></li>
Bill Wendlinga3c6f6b2009-07-20 01:03:30 +0000[diff] [blame]40 </ol>
41 </li>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]42 <li><a href="#callingconv">Calling Conventions</a></li>
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]43 <li><a href="#namedtypes">Named Types</a></li>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]44 <li><a href="#globalvars">Global Variables</a></li>
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]45 <li><a href="#functionstructure">Functions</a></li>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]46 <li><a href="#aliasstructure">Aliases</a></li>
Devang Pateld1a89692010-01-11 19:35:55 +0000[diff] [blame]47 <li><a href="#namedmetadatastructure">Named Metadata</a></li>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]48 <li><a href="#paramattrs">Parameter Attributes</a></li>
Devang Patel9eb525d2008-09-26 23:51:19 +0000[diff] [blame]49 <li><a href="#fnattrs">Function Attributes</a></li>
Gordon Henriksen71183b62007-12-10 03:18:06 +0000[diff] [blame]50 <li><a href="#gc">Garbage Collector Names</a></li>
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]51 <li><a href="#moduleasm">Module-Level Inline Assembly</a></li>
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]52 <li><a href="#datalayout">Data Layout</a></li>
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]53 <li><a href="#pointeraliasing">Pointer Aliasing Rules</a></li>
Jeffrey Yasskin5d284ae2010-04-26 21:21:24 +0000[diff] [blame]54 <li><a href="#volatile">Volatile Memory Accesses</a></li>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]55 </ol>
56 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]57 <li><a href="#typesystem">Type System</a>
58 <ol>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]59 <li><a href="#t_classifications">Type Classifications</a></li>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]60 <li><a href="#t_primitive">Primitive Types</a>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]61 <ol>
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]62 <li><a href="#t_integer">Integer Type</a></li>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]63 <li><a href="#t_floating">Floating Point Types</a></li>
64 <li><a href="#t_void">Void Type</a></li>
65 <li><a href="#t_label">Label Type</a></li>
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]66 <li><a href="#t_metadata">Metadata Type</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]67 </ol>
68 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]69 <li><a href="#t_derived">Derived Types</a>
70 <ol>
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]71 <li><a href="#t_aggregate">Aggregate Types</a>
72 <ol>
73 <li><a href="#t_array">Array Type</a></li>
74 <li><a href="#t_struct">Structure Type</a></li>
75 <li><a href="#t_pstruct">Packed Structure Type</a></li>
76 <li><a href="#t_union">Union Type</a></li>
77 <li><a href="#t_vector">Vector Type</a></li>
78 </ol>
79 </li>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]80 <li><a href="#t_function">Function Type</a></li>
81 <li><a href="#t_pointer">Pointer Type</a></li>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]82 <li><a href="#t_opaque">Opaque Type</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]83 </ol>
84 </li>
Chris Lattnercf7a5842009-02-02 07:32:36 +0000[diff] [blame]85 <li><a href="#t_uprefs">Type Up-references</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]86 </ol>
87 </li>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]88 <li><a href="#constants">Constants</a>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]89 <ol>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]90 <li><a href="#simpleconstants">Simple Constants</a></li>
Chris Lattner361bfcd2009-02-28 18:32:25 +0000[diff] [blame]91 <li><a href="#complexconstants">Complex Constants</a></li>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]92 <li><a href="#globalconstants">Global Variable and Function Addresses</a></li>
93 <li><a href="#undefvalues">Undefined Values</a></li>
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]94 <li><a href="#trapvalues">Trap Values</a></li>
Chris Lattner2bfd3202009-10-27 21:19:13 +0000[diff] [blame]95 <li><a href="#blockaddress">Addresses of Basic Blocks</a></li>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]96 <li><a href="#constantexprs">Constant Expressions</a></li>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]97 </ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]98 </li>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]99 <li><a href="#othervalues">Other Values</a>
100 <ol>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]101 <li><a href="#inlineasm">Inline Assembler Expressions</a></li>
Devang Pateld1a89692010-01-11 19:35:55 +0000[diff] [blame]102 <li><a href="#metadata">Metadata Nodes and Metadata Strings</a></li>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]103 </ol>
104 </li>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]105 <li><a href="#intrinsic_globals">Intrinsic Global Variables</a>
106 <ol>
107 <li><a href="#intg_used">The '<tt>llvm.used</tt>' Global Variable</a></li>
Chris Lattner58f9bb22009-07-20 06:14:25 +0000[diff] [blame]108 <li><a href="#intg_compiler_used">The '<tt>llvm.compiler.used</tt>'
109 Global Variable</a></li>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]110 <li><a href="#intg_global_ctors">The '<tt>llvm.global_ctors</tt>'
111 Global Variable</a></li>
112 <li><a href="#intg_global_dtors">The '<tt>llvm.global_dtors</tt>'
113 Global Variable</a></li>
114 </ol>
115 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]116 <li><a href="#instref">Instruction Reference</a>
117 <ol>
118 <li><a href="#terminators">Terminator Instructions</a>
119 <ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]120 <li><a href="#i_ret">'<tt>ret</tt>' Instruction</a></li>
121 <li><a href="#i_br">'<tt>br</tt>' Instruction</a></li>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]122 <li><a href="#i_switch">'<tt>switch</tt>' Instruction</a></li>
Chris Lattnerd04cb6d2009-10-28 00:19:10 +0000[diff] [blame]123 <li><a href="#i_indirectbr">'<tt>indirectbr</tt>' Instruction</a></li>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]124 <li><a href="#i_invoke">'<tt>invoke</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]125 <li><a href="#i_unwind">'<tt>unwind</tt>' Instruction</a></li>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]126 <li><a href="#i_unreachable">'<tt>unreachable</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]127 </ol>
128 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]129 <li><a href="#binaryops">Binary Operations</a>
130 <ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]131 <li><a href="#i_add">'<tt>add</tt>' Instruction</a></li>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]132 <li><a href="#i_fadd">'<tt>fadd</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]133 <li><a href="#i_sub">'<tt>sub</tt>' Instruction</a></li>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]134 <li><a href="#i_fsub">'<tt>fsub</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]135 <li><a href="#i_mul">'<tt>mul</tt>' Instruction</a></li>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]136 <li><a href="#i_fmul">'<tt>fmul</tt>' Instruction</a></li>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]137 <li><a href="#i_udiv">'<tt>udiv</tt>' Instruction</a></li>
138 <li><a href="#i_sdiv">'<tt>sdiv</tt>' Instruction</a></li>
139 <li><a href="#i_fdiv">'<tt>fdiv</tt>' Instruction</a></li>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]140 <li><a href="#i_urem">'<tt>urem</tt>' Instruction</a></li>
141 <li><a href="#i_srem">'<tt>srem</tt>' Instruction</a></li>
142 <li><a href="#i_frem">'<tt>frem</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]143 </ol>
144 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]145 <li><a href="#bitwiseops">Bitwise Binary Operations</a>
146 <ol>
Reid Spencer2ab01932007-02-02 13:57:07 +0000[diff] [blame]147 <li><a href="#i_shl">'<tt>shl</tt>' Instruction</a></li>
148 <li><a href="#i_lshr">'<tt>lshr</tt>' Instruction</a></li>
149 <li><a href="#i_ashr">'<tt>ashr</tt>' Instruction</a></li>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]150 <li><a href="#i_and">'<tt>and</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]151 <li><a href="#i_or">'<tt>or</tt>' Instruction</a></li>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]152 <li><a href="#i_xor">'<tt>xor</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]153 </ol>
154 </li>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]155 <li><a href="#vectorops">Vector Operations</a>
156 <ol>
157 <li><a href="#i_extractelement">'<tt>extractelement</tt>' Instruction</a></li>
158 <li><a href="#i_insertelement">'<tt>insertelement</tt>' Instruction</a></li>
159 <li><a href="#i_shufflevector">'<tt>shufflevector</tt>' Instruction</a></li>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]160 </ol>
161 </li>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]162 <li><a href="#aggregateops">Aggregate Operations</a>
163 <ol>
164 <li><a href="#i_extractvalue">'<tt>extractvalue</tt>' Instruction</a></li>
165 <li><a href="#i_insertvalue">'<tt>insertvalue</tt>' Instruction</a></li>
166 </ol>
167 </li>
Chris Lattner6ab66722006-08-15 00:45:58 +0000[diff] [blame]168 <li><a href="#memoryops">Memory Access and Addressing Operations</a>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]169 <ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]170 <li><a href="#i_alloca">'<tt>alloca</tt>' Instruction</a></li>
Robert Bocchino820bc75b2006-02-17 21:18:08 +0000[diff] [blame]171 <li><a href="#i_load">'<tt>load</tt>' Instruction</a></li>
172 <li><a href="#i_store">'<tt>store</tt>' Instruction</a></li>
173 <li><a href="#i_getelementptr">'<tt>getelementptr</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]174 </ol>
175 </li>
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]176 <li><a href="#convertops">Conversion Operations</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]177 <ol>
178 <li><a href="#i_trunc">'<tt>trunc .. to</tt>' Instruction</a></li>
179 <li><a href="#i_zext">'<tt>zext .. to</tt>' Instruction</a></li>
180 <li><a href="#i_sext">'<tt>sext .. to</tt>' Instruction</a></li>
181 <li><a href="#i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a></li>
182 <li><a href="#i_fpext">'<tt>fpext .. to</tt>' Instruction</a></li>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]183 <li><a href="#i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a></li>
184 <li><a href="#i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a></li>
185 <li><a href="#i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a></li>
186 <li><a href="#i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a></li>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]187 <li><a href="#i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a></li>
188 <li><a href="#i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a></li>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]189 <li><a href="#i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a></li>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]190 </ol>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]191 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]192 <li><a href="#otherops">Other Operations</a>
193 <ol>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]194 <li><a href="#i_icmp">'<tt>icmp</tt>' Instruction</a></li>
195 <li><a href="#i_fcmp">'<tt>fcmp</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]196 <li><a href="#i_phi">'<tt>phi</tt>' Instruction</a></li>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]197 <li><a href="#i_select">'<tt>select</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]198 <li><a href="#i_call">'<tt>call</tt>' Instruction</a></li>
Chris Lattner33337472006-01-13 23:26:01 +0000[diff] [blame]199 <li><a href="#i_va_arg">'<tt>va_arg</tt>' Instruction</a></li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]200 </ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]201 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]202 </ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]203 </li>
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]204 <li><a href="#intrinsics">Intrinsic Functions</a>
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]205 <ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]206 <li><a href="#int_varargs">Variable Argument Handling Intrinsics</a>
207 <ol>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]208 <li><a href="#int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a></li>
209 <li><a href="#int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a></li>
210 <li><a href="#int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]211 </ol>
212 </li>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]213 <li><a href="#int_gc">Accurate Garbage Collection Intrinsics</a>
214 <ol>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]215 <li><a href="#int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a></li>
216 <li><a href="#int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a></li>
217 <li><a href="#int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a></li>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]218 </ol>
219 </li>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]220 <li><a href="#int_codegen">Code Generator Intrinsics</a>
221 <ol>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]222 <li><a href="#int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a></li>
223 <li><a href="#int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a></li>
224 <li><a href="#int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a></li>
225 <li><a href="#int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a></li>
226 <li><a href="#int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a></li>
227 <li><a href="#int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a></li>
Dan Gohmane58f7b32010-05-26 21:56:15 +0000[diff] [blame]228 <li><a href="#int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a></li>
John Criswellaa1c3c12004-04-09 16:43:20 +0000[diff] [blame]229 </ol>
230 </li>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]231 <li><a href="#int_libc">Standard C Library Intrinsics</a>
232 <ol>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]233 <li><a href="#int_memcpy">'<tt>llvm.memcpy.*</tt>' Intrinsic</a></li>
234 <li><a href="#int_memmove">'<tt>llvm.memmove.*</tt>' Intrinsic</a></li>
235 <li><a href="#int_memset">'<tt>llvm.memset.*</tt>' Intrinsic</a></li>
236 <li><a href="#int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a></li>
237 <li><a href="#int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a></li>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]238 <li><a href="#int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a></li>
239 <li><a href="#int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a></li>
240 <li><a href="#int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a></li>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]241 </ol>
242 </li>
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]243 <li><a href="#int_manip">Bit Manipulation Intrinsics</a>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]244 <ol>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]245 <li><a href="#int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a></li>
Chris Lattnerb748c672006-01-16 22:34:14 +0000[diff] [blame]246 <li><a href="#int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic </a></li>
247 <li><a href="#int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic </a></li>
248 <li><a href="#int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic </a></li>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]249 </ol>
250 </li>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]251 <li><a href="#int_overflow">Arithmetic with Overflow Intrinsics</a>
252 <ol>
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]253 <li><a href="#int_sadd_overflow">'<tt>llvm.sadd.with.overflow.*</tt> Intrinsics</a></li>
254 <li><a href="#int_uadd_overflow">'<tt>llvm.uadd.with.overflow.*</tt> Intrinsics</a></li>
255 <li><a href="#int_ssub_overflow">'<tt>llvm.ssub.with.overflow.*</tt> Intrinsics</a></li>
256 <li><a href="#int_usub_overflow">'<tt>llvm.usub.with.overflow.*</tt> Intrinsics</a></li>
257 <li><a href="#int_smul_overflow">'<tt>llvm.smul.with.overflow.*</tt> Intrinsics</a></li>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]258 <li><a href="#int_umul_overflow">'<tt>llvm.umul.with.overflow.*</tt> Intrinsics</a></li>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]259 </ol>
260 </li>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]261 <li><a href="#int_fp16">Half Precision Floating Point Intrinsics</a>
262 <ol>
Chris Lattnerbbd8bd32010-03-14 23:03:31 +0000[diff] [blame]263 <li><a href="#int_convert_to_fp16">'<tt>llvm.convert.to.fp16</tt>' Intrinsic</a></li>
264 <li><a href="#int_convert_from_fp16">'<tt>llvm.convert.from.fp16</tt>' Intrinsic</a></li>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]265 </ol>
266 </li>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]267 <li><a href="#int_debugger">Debugger intrinsics</a></li>
Jim Laskey2211f492007-03-14 19:31:19 +0000[diff] [blame]268 <li><a href="#int_eh">Exception Handling intrinsics</a></li>
Duncan Sands86e01192007-09-11 14:10:23 +0000[diff] [blame]269 <li><a href="#int_trampoline">Trampoline Intrinsic</a>
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]270 <ol>
271 <li><a href="#int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a></li>
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]272 </ol>
273 </li>
Bill Wendlingf85850f2008-11-18 22:10:53 +0000[diff] [blame]274 <li><a href="#int_atomics">Atomic intrinsics</a>
275 <ol>
276 <li><a href="#int_memory_barrier"><tt>llvm.memory_barrier</tt></a></li>
277 <li><a href="#int_atomic_cmp_swap"><tt>llvm.atomic.cmp.swap</tt></a></li>
278 <li><a href="#int_atomic_swap"><tt>llvm.atomic.swap</tt></a></li>
279 <li><a href="#int_atomic_load_add"><tt>llvm.atomic.load.add</tt></a></li>
280 <li><a href="#int_atomic_load_sub"><tt>llvm.atomic.load.sub</tt></a></li>
281 <li><a href="#int_atomic_load_and"><tt>llvm.atomic.load.and</tt></a></li>
282 <li><a href="#int_atomic_load_nand"><tt>llvm.atomic.load.nand</tt></a></li>
283 <li><a href="#int_atomic_load_or"><tt>llvm.atomic.load.or</tt></a></li>
284 <li><a href="#int_atomic_load_xor"><tt>llvm.atomic.load.xor</tt></a></li>
285 <li><a href="#int_atomic_load_max"><tt>llvm.atomic.load.max</tt></a></li>
286 <li><a href="#int_atomic_load_min"><tt>llvm.atomic.load.min</tt></a></li>
287 <li><a href="#int_atomic_load_umax"><tt>llvm.atomic.load.umax</tt></a></li>
288 <li><a href="#int_atomic_load_umin"><tt>llvm.atomic.load.umin</tt></a></li>
289 </ol>
290 </li>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]291 <li><a href="#int_memorymarkers">Memory Use Markers</a>
292 <ol>
293 <li><a href="#int_lifetime_start"><tt>llvm.lifetime.start</tt></a></li>
294 <li><a href="#int_lifetime_end"><tt>llvm.lifetime.end</tt></a></li>
295 <li><a href="#int_invariant_start"><tt>llvm.invariant.start</tt></a></li>
296 <li><a href="#int_invariant_end"><tt>llvm.invariant.end</tt></a></li>
297 </ol>
298 </li>
Reid Spencer5b2cb0f2007-07-20 19:59:11 +0000[diff] [blame]299 <li><a href="#int_general">General intrinsics</a>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]300 <ol>
Reid Spencer5b2cb0f2007-07-20 19:59:11 +0000[diff] [blame]301 <li><a href="#int_var_annotation">
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]302 '<tt>llvm.var.annotation</tt>' Intrinsic</a></li>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]303 <li><a href="#int_annotation">
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]304 '<tt>llvm.annotation.*</tt>' Intrinsic</a></li>
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]305 <li><a href="#int_trap">
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]306 '<tt>llvm.trap</tt>' Intrinsic</a></li>
307 <li><a href="#int_stackprotector">
308 '<tt>llvm.stackprotector</tt>' Intrinsic</a></li>
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]309 <li><a href="#int_objectsize">
310 '<tt>llvm.objectsize</tt>' Intrinsic</a></li>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]311 </ol>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]312 </li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]313 </ol>
314 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]315</ol>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]316
317<div class="doc_author">
318 <p>Written by <a href="mailto:sabre@nondot.org">Chris Lattner</a>
319 and <a href="mailto:vadve@cs.uiuc.edu">Vikram Adve</a></p>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]320</div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]321
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]322<!-- *********************************************************************** -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]323<div class="doc_section"> <a name="abstract">Abstract </a></div>
324<!-- *********************************************************************** -->
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]325
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]326<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]327
328<p>This document is a reference manual for the LLVM assembly language. LLVM is
329 a Static Single Assignment (SSA) based representation that provides type
330 safety, low-level operations, flexibility, and the capability of representing
331 'all' high-level languages cleanly. It is the common code representation
332 used throughout all phases of the LLVM compilation strategy.</p>
333
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]334</div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]335
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]336<!-- *********************************************************************** -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]337<div class="doc_section"> <a name="introduction">Introduction</a> </div>
338<!-- *********************************************************************** -->
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]339
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]340<div class="doc_text">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]341
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]342<p>The LLVM code representation is designed to be used in three different forms:
343 as an in-memory compiler IR, as an on-disk bitcode representation (suitable
344 for fast loading by a Just-In-Time compiler), and as a human readable
345 assembly language representation. This allows LLVM to provide a powerful
346 intermediate representation for efficient compiler transformations and
347 analysis, while providing a natural means to debug and visualize the
348 transformations. The three different forms of LLVM are all equivalent. This
349 document describes the human readable representation and notation.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]350
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]351<p>The LLVM representation aims to be light-weight and low-level while being
352 expressive, typed, and extensible at the same time. It aims to be a
353 "universal IR" of sorts, by being at a low enough level that high-level ideas
354 may be cleanly mapped to it (similar to how microprocessors are "universal
355 IR's", allowing many source languages to be mapped to them). By providing
356 type information, LLVM can be used as the target of optimizations: for
357 example, through pointer analysis, it can be proven that a C automatic
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]358 variable is never accessed outside of the current function, allowing it to
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]359 be promoted to a simple SSA value instead of a memory location.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]360
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]361</div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]362
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]363<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]364<div class="doc_subsubsection"> <a name="wellformed">Well-Formedness</a> </div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]365
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]366<div class="doc_text">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]367
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]368<p>It is important to note that this document describes 'well formed' LLVM
369 assembly language. There is a difference between what the parser accepts and
370 what is considered 'well formed'. For example, the following instruction is
371 syntactically okay, but not well formed:</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]372
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]373<div class="doc_code">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]374<pre>
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>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]377</div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]378
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]379<p>because the definition of <tt>%x</tt> does not dominate all of its uses. The
380 LLVM infrastructure provides a verification pass that may be used to verify
381 that an LLVM module is well formed. This pass is automatically run by the
382 parser after parsing input assembly and by the optimizer before it outputs
383 bitcode. The violations pointed out by the verifier pass indicate bugs in
384 transformation passes or input to the parser.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]385
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]386</div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]387
Chris Lattner87a3dbe2007-10-03 17:34:29 +0000[diff] [blame]388<!-- Describe the typesetting conventions here. -->
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]389
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]390<!-- *********************************************************************** -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]391<div class="doc_section"> <a name="identifiers">Identifiers</a> </div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]392<!-- *********************************************************************** -->
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]393
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]394<div class="doc_text">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]395
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]396<p>LLVM identifiers come in two basic types: global and local. Global
397 identifiers (functions, global variables) begin with the <tt>'@'</tt>
398 character. Local identifiers (register names, types) begin with
399 the <tt>'%'</tt> character. Additionally, there are three different formats
400 for identifiers, for different purposes:</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]401
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]402<ol>
Reid Spencerb23b65f2007-08-07 14:34:28 +0000[diff] [blame]403 <li>Named values are represented as a string of characters with their prefix.
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]404 For example, <tt>%foo</tt>, <tt>@DivisionByZero</tt>,
405 <tt>%a.really.long.identifier</tt>. The actual regular expression used is
406 '<tt>[%@][a-zA-Z$._][a-zA-Z$._0-9]*</tt>'. Identifiers which require
407 other characters in their names can be surrounded with quotes. Special
408 characters may be escaped using <tt>"\xx"</tt> where <tt>xx</tt> is the
409 ASCII code for the character in hexadecimal. In this way, any character
410 can be used in a name value, even quotes themselves.</li>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]411
Reid Spencerb23b65f2007-08-07 14:34:28 +0000[diff] [blame]412 <li>Unnamed values are represented as an unsigned numeric value with their
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]413 prefix. For example, <tt>%12</tt>, <tt>@2</tt>, <tt>%44</tt>.</li>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]414
Reid Spencer8f08d802004-12-09 18:02:53 +0000[diff] [blame]415 <li>Constants, which are described in a <a href="#constants">section about
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]416 constants</a>, below.</li>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]417</ol>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]418
Reid Spencerb23b65f2007-08-07 14:34:28 +0000[diff] [blame]419<p>LLVM requires that values start with a prefix for two reasons: Compilers
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]420 don't need to worry about name clashes with reserved words, and the set of
421 reserved words may be expanded in the future without penalty. Additionally,
422 unnamed identifiers allow a compiler to quickly come up with a temporary
423 variable without having to avoid symbol table conflicts.</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]424
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]425<p>Reserved words in LLVM are very similar to reserved words in other
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]426 languages. There are keywords for different opcodes
427 ('<tt><a href="#i_add">add</a></tt>',
428 '<tt><a href="#i_bitcast">bitcast</a></tt>',
429 '<tt><a href="#i_ret">ret</a></tt>', etc...), for primitive type names
430 ('<tt><a href="#t_void">void</a></tt>',
431 '<tt><a href="#t_primitive">i32</a></tt>', etc...), and others. These
432 reserved words cannot conflict with variable names, because none of them
433 start with a prefix character (<tt>'%'</tt> or <tt>'@'</tt>).</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]434
435<p>Here is an example of LLVM code to multiply the integer variable
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]436 '<tt>%X</tt>' by 8:</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]437
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]438<p>The easy way:</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]439
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]440<div class="doc_code">
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]441<pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]442%result = <a href="#i_mul">mul</a> i32 %X, 8
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]443</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]444</div>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]445
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]446<p>After strength reduction:</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]447
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]448<div class="doc_code">
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]449<pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]450%result = <a href="#i_shl">shl</a> i32 %X, i8 3
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]451</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]452</div>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]453
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]454<p>And the hard way:</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]455
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]456<div class="doc_code">
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]457<pre>
Gabor Greifbd0328f2009-10-28 13:05:07 +0000[diff] [blame]458%0 = <a href="#i_add">add</a> i32 %X, %X <i>; yields {i32}:%0</i>
459%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]460%result = <a href="#i_add">add</a> i32 %1, %1
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]461</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]462</div>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]463
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]464<p>This last way of multiplying <tt>%X</tt> by 8 illustrates several important
465 lexical features of LLVM:</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]466
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]467<ol>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]468 <li>Comments are delimited with a '<tt>;</tt>' and go until the end of
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]469 line.</li>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]470
471 <li>Unnamed temporaries are created when the result of a computation is not
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]472 assigned to a named value.</li>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]473
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]474 <li>Unnamed temporaries are numbered sequentially</li>
475</ol>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]476
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]477<p>It also shows a convention that we follow in this document. When
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]478 demonstrating instructions, we will follow an instruction with a comment that
479 defines the type and name of value produced. Comments are shown in italic
480 text.</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]481
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]482</div>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]483
484<!-- *********************************************************************** -->
485<div class="doc_section"> <a name="highlevel">High Level Structure</a> </div>
486<!-- *********************************************************************** -->
487
488<!-- ======================================================================= -->
489<div class="doc_subsection"> <a name="modulestructure">Module Structure</a>
490</div>
491
492<div class="doc_text">
493
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]494<p>LLVM programs are composed of "Module"s, each of which is a translation unit
495 of the input programs. Each module consists of functions, global variables,
496 and symbol table entries. Modules may be combined together with the LLVM
497 linker, which merges function (and global variable) definitions, resolves
498 forward declarations, and merges symbol table entries. Here is an example of
499 the "hello world" module:</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]500
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]501<div class="doc_code">
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]502<pre>
503<i>; Declare the string constant as a global constant.</i>
504<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>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]505
506<i>; External declaration of the puts function</i>
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]507<a href="#functionstructure">declare</a> i32 @puts(i8*) <i>; i32 (i8*)* </i>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]508
509<i>; Definition of main function</i>
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]510define i32 @main() { <i>; i32()* </i>
511 <i>; Convert [13 x i8]* to i8 *...</i>
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]512 %cast210 = <a href="#i_getelementptr">getelementptr</a> [13 x i8]* @.LC0, i64 0, i64 0 <i>; i8*</i>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]513
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]514 <i>; Call puts function to write out the string to stdout.</i>
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]515 <a href="#i_call">call</a> i32 @puts(i8* %cast210) <i>; i32</i>
Devang Pateld1a89692010-01-11 19:35:55 +0000[diff] [blame]516 <a href="#i_ret">ret</a> i32 0<br>}
517
518<i>; Named metadata</i>
519!1 = metadata !{i32 41}
520!foo = !{!1, null}
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]521</pre>
522</div>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]523
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]524<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]525 "<tt>.LC0</tt>", an external declaration of the "<tt>puts</tt>" function,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]526 a <a href="#functionstructure">function definition</a> for
Devang Pateld1a89692010-01-11 19:35:55 +0000[diff] [blame]527 "<tt>main</tt>" and <a href="#namedmetadatastructure">named metadata</a>
528 "<tt>foo"</tt>.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]529
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]530<p>In general, a module is made up of a list of global values, where both
531 functions and global variables are global values. Global values are
532 represented by a pointer to a memory location (in this case, a pointer to an
533 array of char, and a pointer to a function), and have one of the
534 following <a href="#linkage">linkage types</a>.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]535
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]536</div>
537
538<!-- ======================================================================= -->
539<div class="doc_subsection">
540 <a name="linkage">Linkage Types</a>
541</div>
542
543<div class="doc_text">
544
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]545<p>All Global Variables and Functions have one of the following types of
546 linkage:</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]547
548<dl>
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]549 <dt><tt><b><a name="linkage_private">private</a></b></tt></dt>
Bill Wendling03bcd6e2010-07-01 21:55:59 +0000[diff] [blame^]550 <dd>Global values with "<tt>private</tt>" linkage are only directly accessible
551 by objects in the current module. In particular, linking code into a
552 module with an private global value may cause the private to be renamed as
553 necessary to avoid collisions. Because the symbol is private to the
554 module, all references can be updated. This doesn't show up in any symbol
555 table in the object file.</dd>
Rafael Espindola6de96a12009-01-15 20:18:42 +0000[diff] [blame]556
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]557 <dt><tt><b><a name="linkage_linker_private">linker_private</a></b></tt></dt>
Bill Wendling03bcd6e2010-07-01 21:55:59 +0000[diff] [blame^]558 <dd>Similar to <tt>private</tt>, but the symbol is passed through the
559 assembler and evaluated by the linker. Unlike normal strong symbols, they
560 are removed by the linker from the final linked image (executable or
561 dynamic library).</dd>
562
563 <dt><tt><b><a name="linkage_linker_private_weak">linker_private_weak</a></b></tt></dt>
564 <dd>Similar to "<tt>linker_private</tt>", but the symbol is weak. Note that
565 <tt>linker_private_weak</tt> symbols are subject to coalescing by the
566 linker. The symbols are removed by the linker from the final linked image
567 (executable or dynamic library).</dd>
Bill Wendlinga3c6f6b2009-07-20 01:03:30 +0000[diff] [blame]568
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]569 <dt><tt><b><a name="linkage_internal">internal</a></b></tt></dt>
Bill Wendling36321712010-06-29 22:34:52 +0000[diff] [blame]570 <dd>Similar to private, but the value shows as a local symbol
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]571 (<tt>STB_LOCAL</tt> in the case of ELF) in the object file. This
572 corresponds to the notion of the '<tt>static</tt>' keyword in C.</dd>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]573
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]574 <dt><tt><b><a name="linkage_available_externally">available_externally</a></b></tt></dt>
Chris Lattner184f1be2009-04-13 05:44:34 +0000[diff] [blame]575 <dd>Globals with "<tt>available_externally</tt>" linkage are never emitted
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]576 into the object file corresponding to the LLVM module. They exist to
577 allow inlining and other optimizations to take place given knowledge of
578 the definition of the global, which is known to be somewhere outside the
579 module. Globals with <tt>available_externally</tt> linkage are allowed to
580 be discarded at will, and are otherwise the same as <tt>linkonce_odr</tt>.
581 This linkage type is only allowed on definitions, not declarations.</dd>
Chris Lattner184f1be2009-04-13 05:44:34 +0000[diff] [blame]582
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]583 <dt><tt><b><a name="linkage_linkonce">linkonce</a></b></tt></dt>
Chris Lattnere20b4702007-01-14 06:51:48 +0000[diff] [blame]584 <dd>Globals with "<tt>linkonce</tt>" linkage are merged with other globals of
Chris Lattner0de4caa2010-01-09 19:15:14 +0000[diff] [blame]585 the same name when linkage occurs. This can be used to implement
586 some forms of inline functions, templates, or other code which must be
587 generated in each translation unit that uses it, but where the body may
588 be overridden with a more definitive definition later. Unreferenced
589 <tt>linkonce</tt> globals are allowed to be discarded. Note that
590 <tt>linkonce</tt> linkage does not actually allow the optimizer to
591 inline the body of this function into callers because it doesn't know if
592 this definition of the function is the definitive definition within the
593 program or whether it will be overridden by a stronger definition.
594 To enable inlining and other optimizations, use "<tt>linkonce_odr</tt>"
595 linkage.</dd>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]596
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]597 <dt><tt><b><a name="linkage_weak">weak</a></b></tt></dt>
Chris Lattnerd0554882009-08-05 05:21:07 +0000[diff] [blame]598 <dd>"<tt>weak</tt>" linkage has the same merging semantics as
599 <tt>linkonce</tt> linkage, except that unreferenced globals with
600 <tt>weak</tt> linkage may not be discarded. This is used for globals that
601 are declared "weak" in C source code.</dd>
602
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]603 <dt><tt><b><a name="linkage_common">common</a></b></tt></dt>
Chris Lattnerd0554882009-08-05 05:21:07 +0000[diff] [blame]604 <dd>"<tt>common</tt>" linkage is most similar to "<tt>weak</tt>" linkage, but
605 they are used for tentative definitions in C, such as "<tt>int X;</tt>" at
606 global scope.
607 Symbols with "<tt>common</tt>" linkage are merged in the same way as
608 <tt>weak symbols</tt>, and they may not be deleted if unreferenced.
Chris Lattner0aff0b22009-08-05 05:41:44 +0000[diff] [blame]609 <tt>common</tt> symbols may not have an explicit section,
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]610 must have a zero initializer, and may not be marked '<a
Chris Lattner0aff0b22009-08-05 05:41:44 +0000[diff] [blame]611 href="#globalvars"><tt>constant</tt></a>'. Functions and aliases may not
612 have common linkage.</dd>
Chris Lattnerd0554882009-08-05 05:21:07 +0000[diff] [blame]613
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]614
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]615 <dt><tt><b><a name="linkage_appending">appending</a></b></tt></dt>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]616 <dd>"<tt>appending</tt>" linkage may only be applied to global variables of
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]617 pointer to array type. When two global variables with appending linkage
618 are linked together, the two global arrays are appended together. This is
619 the LLVM, typesafe, equivalent of having the system linker append together
620 "sections" with identical names when .o files are linked.</dd>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]621
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]622 <dt><tt><b><a name="linkage_externweak">extern_weak</a></b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]623 <dd>The semantics of this linkage follow the ELF object file model: the symbol
624 is weak until linked, if not linked, the symbol becomes null instead of
625 being an undefined reference.</dd>
Anton Korobeynikova0554d92007-01-12 19:20:47 +0000[diff] [blame]626
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]627 <dt><tt><b><a name="linkage_linkonce_odr">linkonce_odr</a></b></tt></dt>
628 <dt><tt><b><a name="linkage_weak_odr">weak_odr</a></b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]629 <dd>Some languages allow differing globals to be merged, such as two functions
630 with different semantics. Other languages, such as <tt>C++</tt>, ensure
Bill Wendling03bcd6e2010-07-01 21:55:59 +0000[diff] [blame^]631 that only equivalent globals are ever merged (the "one definition rule"
632 &mdash; "ODR"). Such languages can use the <tt>linkonce_odr</tt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]633 and <tt>weak_odr</tt> linkage types to indicate that the global will only
634 be merged with equivalent globals. These linkage types are otherwise the
635 same as their non-<tt>odr</tt> versions.</dd>
Duncan Sands12da8ce2009-03-07 15:45:40 +0000[diff] [blame]636
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]637 <dt><tt><b><a name="linkage_external">externally visible</a></b></tt>:</dt>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]638 <dd>If none of the above identifiers are used, the global is externally
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]639 visible, meaning that it participates in linkage and can be used to
640 resolve external symbol references.</dd>
Reid Spencer7972c472007-04-11 23:49:50 +0000[diff] [blame]641</dl>
Anton Korobeynikovd61d39e2006-09-14 18:23:27 +0000[diff] [blame]642
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]643<p>The next two types of linkage are targeted for Microsoft Windows platform
644 only. They are designed to support importing (exporting) symbols from (to)
645 DLLs (Dynamic Link Libraries).</p>
Anton Korobeynikovd61d39e2006-09-14 18:23:27 +0000[diff] [blame]646
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]647<dl>
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]648 <dt><tt><b><a name="linkage_dllimport">dllimport</a></b></tt></dt>
Anton Korobeynikovd61d39e2006-09-14 18:23:27 +0000[diff] [blame]649 <dd>"<tt>dllimport</tt>" linkage causes the compiler to reference a function
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]650 or variable via a global pointer to a pointer that is set up by the DLL
651 exporting the symbol. On Microsoft Windows targets, the pointer name is
652 formed by combining <code>__imp_</code> and the function or variable
653 name.</dd>
Anton Korobeynikovd61d39e2006-09-14 18:23:27 +0000[diff] [blame]654
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]655 <dt><tt><b><a name="linkage_dllexport">dllexport</a></b></tt></dt>
Anton Korobeynikovd61d39e2006-09-14 18:23:27 +0000[diff] [blame]656 <dd>"<tt>dllexport</tt>" linkage causes the compiler to provide a global
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]657 pointer to a pointer in a DLL, so that it can be referenced with the
658 <tt>dllimport</tt> attribute. On Microsoft Windows targets, the pointer
659 name is formed by combining <code>__imp_</code> and the function or
660 variable name.</dd>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]661</dl>
662
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]663<p>For example, since the "<tt>.LC0</tt>" variable is defined to be internal, if
664 another module defined a "<tt>.LC0</tt>" variable and was linked with this
665 one, one of the two would be renamed, preventing a collision. Since
666 "<tt>main</tt>" and "<tt>puts</tt>" are external (i.e., lacking any linkage
667 declarations), they are accessible outside of the current module.</p>
668
669<p>It is illegal for a function <i>declaration</i> to have any linkage type
670 other than "externally visible", <tt>dllimport</tt>
671 or <tt>extern_weak</tt>.</p>
672
Duncan Sands12da8ce2009-03-07 15:45:40 +0000[diff] [blame]673<p>Aliases can have only <tt>external</tt>, <tt>internal</tt>, <tt>weak</tt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]674 or <tt>weak_odr</tt> linkages.</p>
675
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]676</div>
677
678<!-- ======================================================================= -->
679<div class="doc_subsection">
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]680 <a name="callingconv">Calling Conventions</a>
681</div>
682
683<div class="doc_text">
684
685<p>LLVM <a href="#functionstructure">functions</a>, <a href="#i_call">calls</a>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]686 and <a href="#i_invoke">invokes</a> can all have an optional calling
687 convention specified for the call. The calling convention of any pair of
688 dynamic caller/callee must match, or the behavior of the program is
689 undefined. The following calling conventions are supported by LLVM, and more
690 may be added in the future:</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]691
692<dl>
693 <dt><b>"<tt>ccc</tt>" - The C calling convention</b>:</dt>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]694 <dd>This calling convention (the default if no other calling convention is
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]695 specified) matches the target C calling conventions. This calling
696 convention supports varargs function calls and tolerates some mismatch in
697 the declared prototype and implemented declaration of the function (as
698 does normal C).</dd>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]699
700 <dt><b>"<tt>fastcc</tt>" - The fast calling convention</b>:</dt>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]701 <dd>This calling convention attempts to make calls as fast as possible
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]702 (e.g. by passing things in registers). This calling convention allows the
703 target to use whatever tricks it wants to produce fast code for the
704 target, without having to conform to an externally specified ABI
Jeffrey Yasskinb8677462010-01-09 19:44:16 +0000[diff] [blame]705 (Application Binary Interface).
706 <a href="CodeGenerator.html#tailcallopt">Tail calls can only be optimized
Chris Lattnera179e4d2010-03-11 00:22:57 +0000[diff] [blame]707 when this or the GHC convention is used.</a> This calling convention
708 does not support varargs and requires the prototype of all callees to
709 exactly match the prototype of the function definition.</dd>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]710
711 <dt><b>"<tt>coldcc</tt>" - The cold calling convention</b>:</dt>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]712 <dd>This calling convention attempts to make code in the caller as efficient
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]713 as possible under the assumption that the call is not commonly executed.
714 As such, these calls often preserve all registers so that the call does
715 not break any live ranges in the caller side. This calling convention
716 does not support varargs and requires the prototype of all callees to
717 exactly match the prototype of the function definition.</dd>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]718
Chris Lattnera179e4d2010-03-11 00:22:57 +0000[diff] [blame]719 <dt><b>"<tt>cc <em>10</em></tt>" - GHC convention</b>:</dt>
720 <dd>This calling convention has been implemented specifically for use by the
721 <a href="http://www.haskell.org/ghc">Glasgow Haskell Compiler (GHC)</a>.
722 It passes everything in registers, going to extremes to achieve this by
723 disabling callee save registers. This calling convention should not be
724 used lightly but only for specific situations such as an alternative to
725 the <em>register pinning</em> performance technique often used when
726 implementing functional programming languages.At the moment only X86
727 supports this convention and it has the following limitations:
728 <ul>
729 <li>On <em>X86-32</em> only supports up to 4 bit type parameters. No
730 floating point types are supported.</li>
731 <li>On <em>X86-64</em> only supports up to 10 bit type parameters and
732 6 floating point parameters.</li>
733 </ul>
734 This calling convention supports
735 <a href="CodeGenerator.html#tailcallopt">tail call optimization</a> but
736 requires both the caller and callee are using it.
737 </dd>
738
Chris Lattner573f64e2005-05-07 01:46:40 +0000[diff] [blame]739 <dt><b>"<tt>cc &lt;<em>n</em>&gt;</tt>" - Numbered convention</b>:</dt>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]740 <dd>Any calling convention may be specified by number, allowing
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]741 target-specific calling conventions to be used. Target specific calling
742 conventions start at 64.</dd>
Chris Lattner573f64e2005-05-07 01:46:40 +0000[diff] [blame]743</dl>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]744
745<p>More calling conventions can be added/defined on an as-needed basis, to
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]746 support Pascal conventions or any other well-known target-independent
747 convention.</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]748
749</div>
750
751<!-- ======================================================================= -->
752<div class="doc_subsection">
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]753 <a name="visibility">Visibility Styles</a>
754</div>
755
756<div class="doc_text">
757
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]758<p>All Global Variables and Functions have one of the following visibility
759 styles:</p>
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]760
761<dl>
762 <dt><b>"<tt>default</tt>" - Default style</b>:</dt>
Chris Lattner67c37d12008-08-05 18:29:16 +0000[diff] [blame]763 <dd>On targets that use the ELF object file format, default visibility means
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]764 that the declaration is visible to other modules and, in shared libraries,
765 means that the declared entity may be overridden. On Darwin, default
766 visibility means that the declaration is visible to other modules. Default
767 visibility corresponds to "external linkage" in the language.</dd>
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]768
769 <dt><b>"<tt>hidden</tt>" - Hidden style</b>:</dt>
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]770 <dd>Two declarations of an object with hidden visibility refer to the same
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]771 object if they are in the same shared object. Usually, hidden visibility
772 indicates that the symbol will not be placed into the dynamic symbol
773 table, so no other module (executable or shared library) can reference it
774 directly.</dd>
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]775
Anton Korobeynikov39f3cff2007-04-29 18:35:00 +0000[diff] [blame]776 <dt><b>"<tt>protected</tt>" - Protected style</b>:</dt>
Anton Korobeynikov39f3cff2007-04-29 18:35:00 +0000[diff] [blame]777 <dd>On ELF, protected visibility indicates that the symbol will be placed in
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]778 the dynamic symbol table, but that references within the defining module
779 will bind to the local symbol. That is, the symbol cannot be overridden by
780 another module.</dd>
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]781</dl>
782
783</div>
784
785<!-- ======================================================================= -->
786<div class="doc_subsection">
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]787 <a name="namedtypes">Named Types</a>
788</div>
789
790<div class="doc_text">
791
792<p>LLVM IR allows you to specify name aliases for certain types. This can make
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]793 it easier to read the IR and make the IR more condensed (particularly when
794 recursive types are involved). An example of a name specification is:</p>
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]795
796<div class="doc_code">
797<pre>
798%mytype = type { %mytype*, i32 }
799</pre>
800</div>
801
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]802<p>You may give a name to any <a href="#typesystem">type</a> except
803 "<a href="t_void">void</a>". Type name aliases may be used anywhere a type
804 is expected with the syntax "%mytype".</p>
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]805
806<p>Note that type names are aliases for the structural type that they indicate,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]807 and that you can therefore specify multiple names for the same type. This
808 often leads to confusing behavior when dumping out a .ll file. Since LLVM IR
809 uses structural typing, the name is not part of the type. When printing out
810 LLVM IR, the printer will pick <em>one name</em> to render all types of a
811 particular shape. This means that if you have code where two different
812 source types end up having the same LLVM type, that the dumper will sometimes
813 print the "wrong" or unexpected type. This is an important design point and
814 isn't going to change.</p>
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]815
816</div>
817
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]818<!-- ======================================================================= -->
819<div class="doc_subsection">
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]820 <a name="globalvars">Global Variables</a>
821</div>
822
823<div class="doc_text">
824
Chris Lattner5d5aede2005-02-12 19:30:21 +0000[diff] [blame]825<p>Global variables define regions of memory allocated at compilation time
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]826 instead of run-time. Global variables may optionally be initialized, may
827 have an explicit section to be placed in, and may have an optional explicit
828 alignment specified. A variable may be defined as "thread_local", which
829 means that it will not be shared by threads (each thread will have a
830 separated copy of the variable). A variable may be defined as a global
831 "constant," which indicates that the contents of the variable
832 will <b>never</b> be modified (enabling better optimization, allowing the
833 global data to be placed in the read-only section of an executable, etc).
834 Note that variables that need runtime initialization cannot be marked
835 "constant" as there is a store to the variable.</p>
Chris Lattner5d5aede2005-02-12 19:30:21 +0000[diff] [blame]836
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]837<p>LLVM explicitly allows <em>declarations</em> of global variables to be marked
838 constant, even if the final definition of the global is not. This capability
839 can be used to enable slightly better optimization of the program, but
840 requires the language definition to guarantee that optimizations based on the
841 'constantness' are valid for the translation units that do not include the
842 definition.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]843
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]844<p>As SSA values, global variables define pointer values that are in scope
845 (i.e. they dominate) all basic blocks in the program. Global variables
846 always define a pointer to their "content" type because they describe a
847 region of memory, and all memory objects in LLVM are accessed through
848 pointers.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]849
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]850<p>A global variable may be declared to reside in a target-specific numbered
851 address space. For targets that support them, address spaces may affect how
852 optimizations are performed and/or what target instructions are used to
853 access the variable. The default address space is zero. The address space
854 qualifier must precede any other attributes.</p>
Christopher Lamb308121c2007-12-11 09:31:00 +0000[diff] [blame]855
Chris Lattner662c8722005-11-12 00:45:07 +0000[diff] [blame]856<p>LLVM allows an explicit section to be specified for globals. If the target
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]857 supports it, it will emit globals to the section specified.</p>
Chris Lattner662c8722005-11-12 00:45:07 +0000[diff] [blame]858
Chris Lattner78e00bc2010-04-28 00:13:42 +0000[diff] [blame]859<p>An explicit alignment may be specified for a global, which must be a power
860 of 2. If not present, or if the alignment is set to zero, the alignment of
861 the global is set by the target to whatever it feels convenient. If an
862 explicit alignment is specified, the global is forced to have exactly that
Chris Lattner4bd85e42010-04-28 00:31:12 +0000[diff] [blame]863 alignment. Targets and optimizers are not allowed to over-align the global
864 if the global has an assigned section. In this case, the extra alignment
865 could be observable: for example, code could assume that the globals are
866 densely packed in their section and try to iterate over them as an array,
867 alignment padding would break this iteration.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]868
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]869<p>For example, the following defines a global in a numbered address space with
870 an initializer, section, and alignment:</p>
Chris Lattner5760c502007-01-14 00:27:09 +0000[diff] [blame]871
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]872<div class="doc_code">
Chris Lattner5760c502007-01-14 00:27:09 +0000[diff] [blame]873<pre>
Dan Gohmanaaa679b2009-01-11 00:40:00 +0000[diff] [blame]874@G = addrspace(5) constant float 1.0, section "foo", align 4
Chris Lattner5760c502007-01-14 00:27:09 +0000[diff] [blame]875</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]876</div>
Chris Lattner5760c502007-01-14 00:27:09 +0000[diff] [blame]877
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]878</div>
879
880
881<!-- ======================================================================= -->
882<div class="doc_subsection">
883 <a name="functionstructure">Functions</a>
884</div>
885
886<div class="doc_text">
887
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]888<p>LLVM function definitions consist of the "<tt>define</tt>" keyword, an
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]889 optional <a href="#linkage">linkage type</a>, an optional
890 <a href="#visibility">visibility style</a>, an optional
891 <a href="#callingconv">calling convention</a>, a return type, an optional
892 <a href="#paramattrs">parameter attribute</a> for the return type, a function
893 name, a (possibly empty) argument list (each with optional
894 <a href="#paramattrs">parameter attributes</a>), optional
895 <a href="#fnattrs">function attributes</a>, an optional section, an optional
896 alignment, an optional <a href="#gc">garbage collector name</a>, an opening
897 curly brace, a list of basic blocks, and a closing curly brace.</p>
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]898
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]899<p>LLVM function declarations consist of the "<tt>declare</tt>" keyword, an
900 optional <a href="#linkage">linkage type</a>, an optional
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]901 <a href="#visibility">visibility style</a>, an optional
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]902 <a href="#callingconv">calling convention</a>, a return type, an optional
903 <a href="#paramattrs">parameter attribute</a> for the return type, a function
904 name, a possibly empty list of arguments, an optional alignment, and an
905 optional <a href="#gc">garbage collector name</a>.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]906
Chris Lattner67c37d12008-08-05 18:29:16 +0000[diff] [blame]907<p>A function definition contains a list of basic blocks, forming the CFG
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]908 (Control Flow Graph) for the function. Each basic block may optionally start
909 with a label (giving the basic block a symbol table entry), contains a list
910 of instructions, and ends with a <a href="#terminators">terminator</a>
911 instruction (such as a branch or function return).</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]912
Chris Lattnera59fb102007-06-08 16:52:14 +0000[diff] [blame]913<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]914 executed on entrance to the function, and it is not allowed to have
915 predecessor basic blocks (i.e. there can not be any branches to the entry
916 block of a function). Because the block can have no predecessors, it also
917 cannot have any <a href="#i_phi">PHI nodes</a>.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]918
Chris Lattner662c8722005-11-12 00:45:07 +0000[diff] [blame]919<p>LLVM allows an explicit section to be specified for functions. If the target
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]920 supports it, it will emit functions to the section specified.</p>
Chris Lattner662c8722005-11-12 00:45:07 +0000[diff] [blame]921
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]922<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]923 the alignment is set to zero, the alignment of the function is set by the
924 target to whatever it feels convenient. If an explicit alignment is
925 specified, the function is forced to have at least that much alignment. All
926 alignments must be a power of 2.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]927
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]928<h5>Syntax:</h5>
Devang Patel02256232008-10-07 17:48:33 +0000[diff] [blame]929<div class="doc_code">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]930<pre>
Chris Lattner0ae02092008-10-13 16:55:18 +0000[diff] [blame]931define [<a href="#linkage">linkage</a>] [<a href="#visibility">visibility</a>]
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]932 [<a href="#callingconv">cconv</a>] [<a href="#paramattrs">ret attrs</a>]
933 &lt;ResultType&gt; @&lt;FunctionName&gt; ([argument list])
934 [<a href="#fnattrs">fn Attrs</a>] [section "name"] [align N]
935 [<a href="#gc">gc</a>] { ... }
936</pre>
Devang Patel02256232008-10-07 17:48:33 +0000[diff] [blame]937</div>
938
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]939</div>
940
Anton Korobeynikova97b6942007-04-25 14:27:10 +0000[diff] [blame]941<!-- ======================================================================= -->
942<div class="doc_subsection">
943 <a name="aliasstructure">Aliases</a>
944</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]945
Anton Korobeynikova97b6942007-04-25 14:27:10 +0000[diff] [blame]946<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]947
948<p>Aliases act as "second name" for the aliasee value (which can be either
949 function, global variable, another alias or bitcast of global value). Aliases
950 may have an optional <a href="#linkage">linkage type</a>, and an
951 optional <a href="#visibility">visibility style</a>.</p>
Anton Korobeynikova97b6942007-04-25 14:27:10 +0000[diff] [blame]952
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]953<h5>Syntax:</h5>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]954<div class="doc_code">
Bill Wendling2d8b9a82007-05-29 09:42:13 +0000[diff] [blame]955<pre>
Duncan Sands7e99a942008-09-12 20:48:21 +0000[diff] [blame]956@&lt;Name&gt; = alias [Linkage] [Visibility] &lt;AliaseeTy&gt; @&lt;Aliasee&gt;
Bill Wendling2d8b9a82007-05-29 09:42:13 +0000[diff] [blame]957</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]958</div>
Anton Korobeynikova97b6942007-04-25 14:27:10 +0000[diff] [blame]959
960</div>
961
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]962<!-- ======================================================================= -->
Devang Pateld1a89692010-01-11 19:35:55 +0000[diff] [blame]963<div class="doc_subsection">
964 <a name="namedmetadatastructure">Named Metadata</a>
965</div>
966
967<div class="doc_text">
968
Chris Lattnerc2f8f162010-01-15 21:50:19 +0000[diff] [blame]969<p>Named metadata is a collection of metadata. <a href="#metadata">Metadata
970 nodes</a> (but not metadata strings) and null are the only valid operands for
971 a named metadata.</p>
Devang Pateld1a89692010-01-11 19:35:55 +0000[diff] [blame]972
973<h5>Syntax:</h5>
974<div class="doc_code">
975<pre>
976!1 = metadata !{metadata !"one"}
977!name = !{null, !1}
978</pre>
979</div>
980
981</div>
982
983<!-- ======================================================================= -->
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]984<div class="doc_subsection"><a name="paramattrs">Parameter Attributes</a></div>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]985
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]986<div class="doc_text">
987
988<p>The return type and each parameter of a function type may have a set of
989 <i>parameter attributes</i> associated with them. Parameter attributes are
990 used to communicate additional information about the result or parameters of
991 a function. Parameter attributes are considered to be part of the function,
992 not of the function type, so functions with different parameter attributes
993 can have the same function type.</p>
994
995<p>Parameter attributes are simple keywords that follow the type specified. If
996 multiple parameter attributes are needed, they are space separated. For
997 example:</p>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]998
999<div class="doc_code">
1000<pre>
Nick Lewyckydac78d82009-02-15 23:06:14 +0000[diff] [blame]1001declare i32 @printf(i8* noalias nocapture, ...)
Chris Lattnerd2597d72008-10-04 18:33:34 +0000[diff] [blame]1002declare i32 @atoi(i8 zeroext)
1003declare signext i8 @returns_signed_char()
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]1004</pre>
1005</div>
1006
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1007<p>Note that any attributes for the function result (<tt>nounwind</tt>,
1008 <tt>readonly</tt>) come immediately after the argument list.</p>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1009
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1010<p>Currently, only the following parameter attributes are defined:</p>
Chris Lattner5cee13f2008-01-11 06:20:47 +0000[diff] [blame]1011
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1012<dl>
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1013 <dt><tt><b>zeroext</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1014 <dd>This indicates to the code generator that the parameter or return value
1015 should be zero-extended to a 32-bit value by the caller (for a parameter)
1016 or the callee (for a return value).</dd>
Chris Lattner5cee13f2008-01-11 06:20:47 +0000[diff] [blame]1017
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1018 <dt><tt><b>signext</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1019 <dd>This indicates to the code generator that the parameter or return value
1020 should be sign-extended to a 32-bit value by the caller (for a parameter)
1021 or the callee (for a return value).</dd>
Chris Lattner5cee13f2008-01-11 06:20:47 +0000[diff] [blame]1022
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1023 <dt><tt><b>inreg</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1024 <dd>This indicates that this parameter or return value should be treated in a
1025 special target-dependent fashion during while emitting code for a function
1026 call or return (usually, by putting it in a register as opposed to memory,
1027 though some targets use it to distinguish between two different kinds of
1028 registers). Use of this attribute is target-specific.</dd>
Chris Lattner5cee13f2008-01-11 06:20:47 +0000[diff] [blame]1029
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1030 <dt><tt><b><a name="byval">byval</a></b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1031 <dd>This indicates that the pointer parameter should really be passed by value
1032 to the function. The attribute implies that a hidden copy of the pointee
1033 is made between the caller and the callee, so the callee is unable to
1034 modify the value in the callee. This attribute is only valid on LLVM
1035 pointer arguments. It is generally used to pass structs and arrays by
1036 value, but is also valid on pointers to scalars. The copy is considered
1037 to belong to the caller not the callee (for example,
1038 <tt><a href="#readonly">readonly</a></tt> functions should not write to
1039 <tt>byval</tt> parameters). This is not a valid attribute for return
1040 values. The byval attribute also supports specifying an alignment with
1041 the align attribute. This has a target-specific effect on the code
1042 generator that usually indicates a desired alignment for the synthesized
1043 stack slot.</dd>
1044
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1045 <dt><tt><b>sret</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1046 <dd>This indicates that the pointer parameter specifies the address of a
1047 structure that is the return value of the function in the source program.
1048 This pointer must be guaranteed by the caller to be valid: loads and
1049 stores to the structure may be assumed by the callee to not to trap. This
1050 may only be applied to the first parameter. This is not a valid attribute
1051 for return values. </dd>
1052
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1053 <dt><tt><b>noalias</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1054 <dd>This indicates that the pointer does not alias any global or any other
1055 parameter. The caller is responsible for ensuring that this is the
1056 case. On a function return value, <tt>noalias</tt> additionally indicates
1057 that the pointer does not alias any other pointers visible to the
1058 caller. For further details, please see the discussion of the NoAlias
1059 response in
1060 <a href="http://llvm.org/docs/AliasAnalysis.html#MustMayNo">alias
1061 analysis</a>.</dd>
1062
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1063 <dt><tt><b>nocapture</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1064 <dd>This indicates that the callee does not make any copies of the pointer
1065 that outlive the callee itself. This is not a valid attribute for return
1066 values.</dd>
1067
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1068 <dt><tt><b>nest</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1069 <dd>This indicates that the pointer parameter can be excised using the
1070 <a href="#int_trampoline">trampoline intrinsics</a>. This is not a valid
1071 attribute for return values.</dd>
1072</dl>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1073
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1074</div>
1075
1076<!-- ======================================================================= -->
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]1077<div class="doc_subsection">
Gordon Henriksen71183b62007-12-10 03:18:06 +0000[diff] [blame]1078 <a name="gc">Garbage Collector Names</a>
1079</div>
1080
1081<div class="doc_text">
Gordon Henriksen71183b62007-12-10 03:18:06 +0000[diff] [blame]1082
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1083<p>Each function may specify a garbage collector name, which is simply a
1084 string:</p>
1085
1086<div class="doc_code">
1087<pre>
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1088define void @f() gc "name" { ... }
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1089</pre>
1090</div>
Gordon Henriksen71183b62007-12-10 03:18:06 +0000[diff] [blame]1091
1092<p>The compiler declares the supported values of <i>name</i>. Specifying a
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1093 collector which will cause the compiler to alter its output in order to
1094 support the named garbage collection algorithm.</p>
1095
Gordon Henriksen71183b62007-12-10 03:18:06 +0000[diff] [blame]1096</div>
1097
1098<!-- ======================================================================= -->
1099<div class="doc_subsection">
Devang Patel9eb525d2008-09-26 23:51:19 +0000[diff] [blame]1100 <a name="fnattrs">Function Attributes</a>
Devang Patelcaacdba2008-09-04 23:05:13 +0000[diff] [blame]1101</div>
1102
1103<div class="doc_text">
Devang Patel9eb525d2008-09-26 23:51:19 +0000[diff] [blame]1104
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1105<p>Function attributes are set to communicate additional information about a
1106 function. Function attributes are considered to be part of the function, not
1107 of the function type, so functions with different parameter attributes can
1108 have the same function type.</p>
Devang Patel9eb525d2008-09-26 23:51:19 +0000[diff] [blame]1109
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1110<p>Function attributes are simple keywords that follow the type specified. If
1111 multiple attributes are needed, they are space separated. For example:</p>
Devang Patelcaacdba2008-09-04 23:05:13 +0000[diff] [blame]1112
1113<div class="doc_code">
Bill Wendlingb175fa42008-09-07 10:26:33 +0000[diff] [blame]1114<pre>
Devang Patel9eb525d2008-09-26 23:51:19 +0000[diff] [blame]1115define void @f() noinline { ... }
1116define void @f() alwaysinline { ... }
1117define void @f() alwaysinline optsize { ... }
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1118define void @f() optsize { ... }
Bill Wendlingb175fa42008-09-07 10:26:33 +0000[diff] [blame]1119</pre>
Devang Patelcaacdba2008-09-04 23:05:13 +0000[diff] [blame]1120</div>
1121
Bill Wendlingb175fa42008-09-07 10:26:33 +0000[diff] [blame]1122<dl>
Charles Davisbe5557e2010-02-12 00:31:15 +0000[diff] [blame]1123 <dt><tt><b>alignstack(&lt;<em>n</em>&gt;)</b></tt></dt>
1124 <dd>This attribute indicates that, when emitting the prologue and epilogue,
1125 the backend should forcibly align the stack pointer. Specify the
1126 desired alignment, which must be a power of two, in parentheses.
1127
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1128 <dt><tt><b>alwaysinline</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1129 <dd>This attribute indicates that the inliner should attempt to inline this
1130 function into callers whenever possible, ignoring any active inlining size
1131 threshold for this caller.</dd>
Bill Wendlingb175fa42008-09-07 10:26:33 +0000[diff] [blame]1132
Jakob Stoklund Olesen74bb06c2010-02-06 01:16:28 +0000[diff] [blame]1133 <dt><tt><b>inlinehint</b></tt></dt>
1134 <dd>This attribute indicates that the source code contained a hint that inlining
1135 this function is desirable (such as the "inline" keyword in C/C++). It
1136 is just a hint; it imposes no requirements on the inliner.</dd>
1137
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1138 <dt><tt><b>noinline</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1139 <dd>This attribute indicates that the inliner should never inline this
1140 function in any situation. This attribute may not be used together with
1141 the <tt>alwaysinline</tt> attribute.</dd>
Devang Patel9eb525d2008-09-26 23:51:19 +0000[diff] [blame]1142
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1143 <dt><tt><b>optsize</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1144 <dd>This attribute suggests that optimization passes and code generator passes
1145 make choices that keep the code size of this function low, and otherwise
1146 do optimizations specifically to reduce code size.</dd>
Devang Patel9eb525d2008-09-26 23:51:19 +0000[diff] [blame]1147
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1148 <dt><tt><b>noreturn</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1149 <dd>This function attribute indicates that the function never returns
1150 normally. This produces undefined behavior at runtime if the function
1151 ever does dynamically return.</dd>
Bill Wendlinga8130172008-11-13 01:02:51 +0000[diff] [blame]1152
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1153 <dt><tt><b>nounwind</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1154 <dd>This function attribute indicates that the function never returns with an
1155 unwind or exceptional control flow. If the function does unwind, its
1156 runtime behavior is undefined.</dd>
Bill Wendling0f5541e2008-11-26 19:07:40 +0000[diff] [blame]1157
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1158 <dt><tt><b>readnone</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1159 <dd>This attribute indicates that the function computes its result (or decides
1160 to unwind an exception) based strictly on its arguments, without
1161 dereferencing any pointer arguments or otherwise accessing any mutable
1162 state (e.g. memory, control registers, etc) visible to caller functions.
1163 It does not write through any pointer arguments
1164 (including <tt><a href="#byval">byval</a></tt> arguments) and never
1165 changes any state visible to callers. This means that it cannot unwind
1166 exceptions by calling the <tt>C++</tt> exception throwing methods, but
1167 could use the <tt>unwind</tt> instruction.</dd>
Devang Patel310fd4a2009-06-12 19:45:19 +0000[diff] [blame]1168
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1169 <dt><tt><b><a name="readonly">readonly</a></b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1170 <dd>This attribute indicates that the function does not write through any
1171 pointer arguments (including <tt><a href="#byval">byval</a></tt>
1172 arguments) or otherwise modify any state (e.g. memory, control registers,
1173 etc) visible to caller functions. It may dereference pointer arguments
1174 and read state that may be set in the caller. A readonly function always
1175 returns the same value (or unwinds an exception identically) when called
1176 with the same set of arguments and global state. It cannot unwind an
1177 exception by calling the <tt>C++</tt> exception throwing methods, but may
1178 use the <tt>unwind</tt> instruction.</dd>
Anton Korobeynikovc8ce7b082009-07-17 18:07:26 +0000[diff] [blame]1179
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1180 <dt><tt><b><a name="ssp">ssp</a></b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1181 <dd>This attribute indicates that the function should emit a stack smashing
1182 protector. It is in the form of a "canary"&mdash;a random value placed on
1183 the stack before the local variables that's checked upon return from the
1184 function to see if it has been overwritten. A heuristic is used to
1185 determine if a function needs stack protectors or not.<br>
1186<br>
1187 If a function that has an <tt>ssp</tt> attribute is inlined into a
1188 function that doesn't have an <tt>ssp</tt> attribute, then the resulting
1189 function will have an <tt>ssp</tt> attribute.</dd>
1190
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1191 <dt><tt><b>sspreq</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1192 <dd>This attribute indicates that the function should <em>always</em> emit a
1193 stack smashing protector. This overrides
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1194 the <tt><a href="#ssp">ssp</a></tt> function attribute.<br>
1195<br>
1196 If a function that has an <tt>sspreq</tt> attribute is inlined into a
1197 function that doesn't have an <tt>sspreq</tt> attribute or which has
1198 an <tt>ssp</tt> attribute, then the resulting function will have
1199 an <tt>sspreq</tt> attribute.</dd>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1200
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1201 <dt><tt><b>noredzone</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1202 <dd>This attribute indicates that the code generator should not use a red
1203 zone, even if the target-specific ABI normally permits it.</dd>
1204
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1205 <dt><tt><b>noimplicitfloat</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1206 <dd>This attributes disables implicit floating point instructions.</dd>
1207
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1208 <dt><tt><b>naked</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1209 <dd>This attribute disables prologue / epilogue emission for the function.
1210 This can have very system-specific consequences.</dd>
Bill Wendlingb175fa42008-09-07 10:26:33 +0000[diff] [blame]1211</dl>
1212
Devang Patelcaacdba2008-09-04 23:05:13 +0000[diff] [blame]1213</div>
1214
1215<!-- ======================================================================= -->
1216<div class="doc_subsection">
Chris Lattner93564892006-04-08 04:40:53 +0000[diff] [blame]1217 <a name="moduleasm">Module-Level Inline Assembly</a>
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]1218</div>
1219
1220<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1221
1222<p>Modules may contain "module-level inline asm" blocks, which corresponds to
1223 the GCC "file scope inline asm" blocks. These blocks are internally
1224 concatenated by LLVM and treated as a single unit, but may be separated in
1225 the <tt>.ll</tt> file if desired. The syntax is very simple:</p>
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]1226
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]1227<div class="doc_code">
1228<pre>
1229module asm "inline asm code goes here"
1230module asm "more can go here"
1231</pre>
1232</div>
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]1233
1234<p>The strings can contain any character by escaping non-printable characters.
1235 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]1236 for the number.</p>
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]1237
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1238<p>The inline asm code is simply printed to the machine code .s file when
1239 assembly code is generated.</p>
1240
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]1241</div>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]1242
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1243<!-- ======================================================================= -->
1244<div class="doc_subsection">
1245 <a name="datalayout">Data Layout</a>
1246</div>
1247
1248<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1249
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1250<p>A module may specify a target specific data layout string that specifies how
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1251 data is to be laid out in memory. The syntax for the data layout is
1252 simply:</p>
1253
1254<div class="doc_code">
1255<pre>
1256target datalayout = "<i>layout specification</i>"
1257</pre>
1258</div>
1259
1260<p>The <i>layout specification</i> consists of a list of specifications
1261 separated by the minus sign character ('-'). Each specification starts with
1262 a letter and may include other information after the letter to define some
1263 aspect of the data layout. The specifications accepted are as follows:</p>
1264
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1265<dl>
1266 <dt><tt>E</tt></dt>
1267 <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]1268 bits with the most significance have the lowest address location.</dd>
1269
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1270 <dt><tt>e</tt></dt>
Chris Lattner67c37d12008-08-05 18:29:16 +0000[diff] [blame]1271 <dd>Specifies that the target lays out data in little-endian form. That is,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1272 the bits with the least significance have the lowest address
1273 location.</dd>
1274
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1275 <dt><tt>p:<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]1276 <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]1277 <i>preferred</i> alignments. All sizes are in bits. Specifying
1278 the <i>pref</i> alignment is optional. If omitted, the
1279 preceding <tt>:</tt> should be omitted too.</dd>
1280
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1281 <dt><tt>i<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1282 <dd>This specifies the alignment for an integer type of a given bit
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1283 <i>size</i>. The value of <i>size</i> must be in the range [1,2^23).</dd>
1284
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1285 <dt><tt>v<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]1286 <dd>This specifies the alignment for a vector type of a given bit
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1287 <i>size</i>.</dd>
1288
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1289 <dt><tt>f<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]1290 <dd>This specifies the alignment for a floating point type of a given bit
Dale Johannesence522852010-05-28 18:54:47 +0000[diff] [blame]1291 <i>size</i>. Only values of <i>size</i> that are supported by the target
1292 will work. 32 (float) and 64 (double) are supported on all targets;
1293 80 or 128 (different flavors of long double) are also supported on some
1294 targets.
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1295
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1296 <dt><tt>a<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1297 <dd>This specifies the alignment for an aggregate type of a given bit
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1298 <i>size</i>.</dd>
1299
Daniel Dunbar7921a592009-06-08 22:17:53 +0000[diff] [blame]1300 <dt><tt>s<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1301 <dd>This specifies the alignment for a stack object of a given bit
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1302 <i>size</i>.</dd>
Chris Lattnera381eff2009-11-07 09:35:34 +0000[diff] [blame]1303
1304 <dt><tt>n<i>size1</i>:<i>size2</i>:<i>size3</i>...</tt></dt>
1305 <dd>This specifies a set of native integer widths for the target CPU
1306 in bits. For example, it might contain "n32" for 32-bit PowerPC,
1307 "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]1308 this set are considered to support most general arithmetic
Chris Lattnera381eff2009-11-07 09:35:34 +0000[diff] [blame]1309 operations efficiently.</dd>
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1310</dl>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1311
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1312<p>When constructing the data layout for a given target, LLVM starts with a
Dan Gohman61110ae2010-04-28 00:36:01 +0000[diff] [blame]1313 default set of specifications which are then (possibly) overridden by the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1314 specifications in the <tt>datalayout</tt> keyword. The default specifications
1315 are given in this list:</p>
1316
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1317<ul>
1318 <li><tt>E</tt> - big endian</li>
Dan Gohman8ad777d2010-02-23 02:44:03 +0000[diff] [blame]1319 <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]1320 <li><tt>i1:8:8</tt> - i1 is 8-bit (byte) aligned</li>
1321 <li><tt>i8:8:8</tt> - i8 is 8-bit (byte) aligned</li>
1322 <li><tt>i16:16:16</tt> - i16 is 16-bit aligned</li>
1323 <li><tt>i32:32:32</tt> - i32 is 32-bit aligned</li>
Chris Lattner67c37d12008-08-05 18:29:16 +0000[diff] [blame]1324 <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]1325 alignment of 64-bits</li>
1326 <li><tt>f32:32:32</tt> - float is 32-bit aligned</li>
1327 <li><tt>f64:64:64</tt> - double is 64-bit aligned</li>
1328 <li><tt>v64:64:64</tt> - 64-bit vector is 64-bit aligned</li>
1329 <li><tt>v128:128:128</tt> - 128-bit vector is 128-bit aligned</li>
1330 <li><tt>a0:0:1</tt> - aggregates are 8-bit aligned</li>
Daniel Dunbar7921a592009-06-08 22:17:53 +0000[diff] [blame]1331 <li><tt>s0:64:64</tt> - stack objects are 64-bit aligned</li>
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1332</ul>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1333
1334<p>When LLVM is determining the alignment for a given type, it uses the
1335 following rules:</p>
1336
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1337<ol>
1338 <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]1339 specification is used.</li>
1340
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1341 <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]1342 smallest integer type that is larger than the bitwidth of the sought type
1343 is used. If none of the specifications are larger than the bitwidth then
1344 the the largest integer type is used. For example, given the default
1345 specifications above, the i7 type will use the alignment of i8 (next
1346 largest) while both i65 and i256 will use the alignment of i64 (largest
1347 specified).</li>
1348
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1349 <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]1350 largest vector type that is smaller than the sought vector type will be
1351 used as a fall back. This happens because &lt;128 x double&gt; can be
1352 implemented in terms of 64 &lt;2 x double&gt;, for example.</li>
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1353</ol>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1354
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1355</div>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]1356
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1357<!-- ======================================================================= -->
1358<div class="doc_subsection">
1359 <a name="pointeraliasing">Pointer Aliasing Rules</a>
1360</div>
1361
1362<div class="doc_text">
1363
Andreas Bolka8ae4e242009-07-29 00:02:05 +0000[diff] [blame]1364<p>Any memory access must be done through a pointer value associated
Andreas Bolkae39f0332009-07-27 20:37:10 +0000[diff] [blame]1365with an address range of the memory access, otherwise the behavior
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1366is undefined. Pointer values are associated with address ranges
1367according to the following rules:</p>
1368
1369<ul>
Andreas Bolka8ae4e242009-07-29 00:02:05 +0000[diff] [blame]1370 <li>A pointer value formed from a
1371 <tt><a href="#i_getelementptr">getelementptr</a></tt> instruction
1372 is associated with the addresses associated with the first operand
1373 of the <tt>getelementptr</tt>.</li>
1374 <li>An address of a global variable is associated with the address
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1375 range of the variable's storage.</li>
1376 <li>The result value of an allocation instruction is associated with
1377 the address range of the allocated storage.</li>
1378 <li>A null pointer in the default address-space is associated with
Andreas Bolka8ae4e242009-07-29 00:02:05 +0000[diff] [blame]1379 no address.</li>
1380 <li>A pointer value formed by an
1381 <tt><a href="#i_inttoptr">inttoptr</a></tt> is associated with all
1382 address ranges of all pointer values that contribute (directly or
1383 indirectly) to the computation of the pointer's value.</li>
1384 <li>The result value of a
1385 <tt><a href="#i_bitcast">bitcast</a></tt> is associated with all
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1386 addresses associated with the operand of the <tt>bitcast</tt>.</li>
1387 <li>An integer constant other than zero or a pointer value returned
1388 from a function not defined within LLVM may be associated with address
1389 ranges allocated through mechanisms other than those provided by
Andreas Bolka8ae4e242009-07-29 00:02:05 +0000[diff] [blame]1390 LLVM. Such ranges shall not overlap with any ranges of addresses
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1391 allocated by mechanisms provided by LLVM.</li>
1392 </ul>
1393
1394<p>LLVM IR does not associate types with memory. The result type of a
Andreas Bolka8ae4e242009-07-29 00:02:05 +0000[diff] [blame]1395<tt><a href="#i_load">load</a></tt> merely indicates the size and
1396alignment of the memory from which to load, as well as the
Dan Gohman4eb47192010-06-17 19:23:50 +0000[diff] [blame]1397interpretation of the value. The first operand type of a
Andreas Bolka8ae4e242009-07-29 00:02:05 +0000[diff] [blame]1398<tt><a href="#i_store">store</a></tt> similarly only indicates the size
1399and alignment of the store.</p>
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1400
1401<p>Consequently, type-based alias analysis, aka TBAA, aka
1402<tt>-fstrict-aliasing</tt>, is not applicable to general unadorned
1403LLVM IR. <a href="#metadata">Metadata</a> may be used to encode
1404additional information which specialized optimization passes may use
1405to implement type-based alias analysis.</p>
1406
1407</div>
1408
Jeffrey Yasskin5d284ae2010-04-26 21:21:24 +0000[diff] [blame]1409<!-- ======================================================================= -->
1410<div class="doc_subsection">
1411 <a name="volatile">Volatile Memory Accesses</a>
1412</div>
1413
1414<div class="doc_text">
1415
1416<p>Certain memory accesses, such as <a href="#i_load"><tt>load</tt></a>s, <a
1417href="#i_store"><tt>store</tt></a>s, and <a
1418href="#int_memcpy"><tt>llvm.memcpy</tt></a>s may be marked <tt>volatile</tt>.
1419The optimizers must not change the number of volatile operations or change their
1420order of execution relative to other volatile operations. The optimizers
1421<i>may</i> change the order of volatile operations relative to non-volatile
1422operations. This is not Java's "volatile" and has no cross-thread
1423synchronization behavior.</p>
1424
1425</div>
1426
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1427<!-- *********************************************************************** -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1428<div class="doc_section"> <a name="typesystem">Type System</a> </div>
1429<!-- *********************************************************************** -->
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]1430
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1431<div class="doc_text">
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]1432
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1433<p>The LLVM type system is one of the most important features of the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1434 intermediate representation. Being typed enables a number of optimizations
1435 to be performed on the intermediate representation directly, without having
1436 to do extra analyses on the side before the transformation. A strong type
1437 system makes it easier to read the generated code and enables novel analyses
1438 and transformations that are not feasible to perform on normal three address
1439 code representations.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]1440
1441</div>
1442
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1443<!-- ======================================================================= -->
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1444<div class="doc_subsection"> <a name="t_classifications">Type
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1445Classifications</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1446
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1447<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1448
1449<p>The types fall into a few useful classifications:</p>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]1450
1451<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1452 <tbody>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1453 <tr><th>Classification</th><th>Types</th></tr>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1454 <tr>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1455 <td><a href="#t_integer">integer</a></td>
Reid Spencer138249b2007-05-16 18:44:01 +0000[diff] [blame]1456 <td><tt>i1, i2, i3, ... i8, ... i16, ... i32, ... i64, ... </tt></td>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1457 </tr>
1458 <tr>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1459 <td><a href="#t_floating">floating point</a></td>
1460 <td><tt>float, double, x86_fp80, fp128, ppc_fp128</tt></td>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1461 </tr>
1462 <tr>
1463 <td><a name="t_firstclass">first class</a></td>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1464 <td><a href="#t_integer">integer</a>,
1465 <a href="#t_floating">floating point</a>,
1466 <a href="#t_pointer">pointer</a>,
Dan Gohman08783a882008-06-18 18:42:13 +0000[diff] [blame]1467 <a href="#t_vector">vector</a>,
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]1468 <a href="#t_struct">structure</a>,
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]1469 <a href="#t_union">union</a>,
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]1470 <a href="#t_array">array</a>,
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1471 <a href="#t_label">label</a>,
1472 <a href="#t_metadata">metadata</a>.
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1473 </td>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1474 </tr>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1475 <tr>
1476 <td><a href="#t_primitive">primitive</a></td>
1477 <td><a href="#t_label">label</a>,
1478 <a href="#t_void">void</a>,
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1479 <a href="#t_floating">floating point</a>,
1480 <a href="#t_metadata">metadata</a>.</td>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1481 </tr>
1482 <tr>
1483 <td><a href="#t_derived">derived</a></td>
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]1484 <td><a href="#t_array">array</a>,
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1485 <a href="#t_function">function</a>,
1486 <a href="#t_pointer">pointer</a>,
1487 <a href="#t_struct">structure</a>,
1488 <a href="#t_pstruct">packed structure</a>,
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]1489 <a href="#t_union">union</a>,
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1490 <a href="#t_vector">vector</a>,
1491 <a href="#t_opaque">opaque</a>.
Dan Gohman93bf60d2008-10-14 16:32:04 +0000[diff] [blame]1492 </td>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1493 </tr>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1494 </tbody>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1495</table>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]1496
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1497<p>The <a href="#t_firstclass">first class</a> types are perhaps the most
1498 important. Values of these types are the only ones which can be produced by
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]1499 instructions.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1500
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1501</div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1502
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1503<!-- ======================================================================= -->
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1504<div class="doc_subsection"> <a name="t_primitive">Primitive Types</a> </div>
Chris Lattner43542b32008-01-04 04:34:14 +0000[diff] [blame]1505
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1506<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1507
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1508<p>The primitive types are the fundamental building blocks of the LLVM
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1509 system.</p>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1510
Chris Lattner43542b32008-01-04 04:34:14 +0000[diff] [blame]1511</div>
1512
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1513<!-- _______________________________________________________________________ -->
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]1514<div class="doc_subsubsection"> <a name="t_integer">Integer Type</a> </div>
1515
1516<div class="doc_text">
1517
1518<h5>Overview:</h5>
1519<p>The integer type is a very simple type that simply specifies an arbitrary
1520 bit width for the integer type desired. Any bit width from 1 bit to
1521 2<sup>23</sup>-1 (about 8 million) can be specified.</p>
1522
1523<h5>Syntax:</h5>
1524<pre>
1525 iN
1526</pre>
1527
1528<p>The number of bits the integer will occupy is specified by the <tt>N</tt>
1529 value.</p>
1530
1531<h5>Examples:</h5>
1532<table class="layout">
1533 <tr class="layout">
1534 <td class="left"><tt>i1</tt></td>
1535 <td class="left">a single-bit integer.</td>
1536 </tr>
1537 <tr class="layout">
1538 <td class="left"><tt>i32</tt></td>
1539 <td class="left">a 32-bit integer.</td>
1540 </tr>
1541 <tr class="layout">
1542 <td class="left"><tt>i1942652</tt></td>
1543 <td class="left">a really big integer of over 1 million bits.</td>
1544 </tr>
1545</table>
1546
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]1547</div>
1548
1549<!-- _______________________________________________________________________ -->
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1550<div class="doc_subsubsection"> <a name="t_floating">Floating Point Types</a> </div>
1551
1552<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1553
1554<table>
1555 <tbody>
1556 <tr><th>Type</th><th>Description</th></tr>
1557 <tr><td><tt>float</tt></td><td>32-bit floating point value</td></tr>
1558 <tr><td><tt>double</tt></td><td>64-bit floating point value</td></tr>
1559 <tr><td><tt>fp128</tt></td><td>128-bit floating point value (112-bit mantissa)</td></tr>
1560 <tr><td><tt>x86_fp80</tt></td><td>80-bit floating point value (X87)</td></tr>
1561 <tr><td><tt>ppc_fp128</tt></td><td>128-bit floating point value (two 64-bits)</td></tr>
1562 </tbody>
1563</table>
1564
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1565</div>
1566
1567<!-- _______________________________________________________________________ -->
1568<div class="doc_subsubsection"> <a name="t_void">Void Type</a> </div>
1569
1570<div class="doc_text">
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1571
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1572<h5>Overview:</h5>
1573<p>The void type does not represent any value and has no size.</p>
1574
1575<h5>Syntax:</h5>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1576<pre>
1577 void
1578</pre>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1579
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1580</div>
1581
1582<!-- _______________________________________________________________________ -->
1583<div class="doc_subsubsection"> <a name="t_label">Label Type</a> </div>
1584
1585<div class="doc_text">
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1586
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1587<h5>Overview:</h5>
1588<p>The label type represents code labels.</p>
1589
1590<h5>Syntax:</h5>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1591<pre>
1592 label
1593</pre>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1594
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1595</div>
1596
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1597<!-- _______________________________________________________________________ -->
1598<div class="doc_subsubsection"> <a name="t_metadata">Metadata Type</a> </div>
1599
1600<div class="doc_text">
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1601
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1602<h5>Overview:</h5>
Nick Lewycky93e06a52009-09-27 23:27:42 +0000[diff] [blame]1603<p>The metadata type represents embedded metadata. No derived types may be
1604 created from metadata except for <a href="#t_function">function</a>
1605 arguments.
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1606
1607<h5>Syntax:</h5>
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1608<pre>
1609 metadata
1610</pre>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1611
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1612</div>
1613
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1614
1615<!-- ======================================================================= -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1616<div class="doc_subsection"> <a name="t_derived">Derived Types</a> </div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1617
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1618<div class="doc_text">
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1619
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1620<p>The real power in LLVM comes from the derived types in the system. This is
1621 what allows a programmer to represent arrays, functions, pointers, and other
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]1622 useful types. Each of these types contain one or more element types which
1623 may be a primitive type, or another derived type. For example, it is
1624 possible to have a two dimensional array, using an array as the element type
1625 of another array.</p>
Dan Gohman142ccc02009-01-24 15:58:40 +0000[diff] [blame]1626
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]1627
1628</div>
1629
1630<!-- _______________________________________________________________________ -->
1631<div class="doc_subsubsection"> <a name="t_aggregate">Aggregate Types</a> </div>
1632
1633<div class="doc_text">
1634
1635<p>Aggregate Types are a subset of derived types that can contain multiple
1636 member types. <a href="#t_array">Arrays</a>,
1637 <a href="#t_struct">structs</a>, <a href="#t_vector">vectors</a> and
1638 <a href="#t_union">unions</a> are aggregate types.</p>
1639
1640</div>
1641
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]1642</div>
Reid Spencer138249b2007-05-16 18:44:01 +0000[diff] [blame]1643
1644<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1645<div class="doc_subsubsection"> <a name="t_array">Array Type</a> </div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1646
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1647<div class="doc_text">
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1648
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1649<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1650<p>The array type is a very simple derived type that arranges elements
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1651 sequentially in memory. The array type requires a size (number of elements)
1652 and an underlying data type.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1653
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]1654<h5>Syntax:</h5>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1655<pre>
1656 [&lt;# elements&gt; x &lt;elementtype&gt;]
1657</pre>
1658
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1659<p>The number of elements is a constant integer value; <tt>elementtype</tt> may
1660 be any type with a size.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1661
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]1662<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1663<table class="layout">
1664 <tr class="layout">
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]1665 <td class="left"><tt>[40 x i32]</tt></td>
1666 <td class="left">Array of 40 32-bit integer values.</td>
1667 </tr>
1668 <tr class="layout">
1669 <td class="left"><tt>[41 x i32]</tt></td>
1670 <td class="left">Array of 41 32-bit integer values.</td>
1671 </tr>
1672 <tr class="layout">
1673 <td class="left"><tt>[4 x i8]</tt></td>
1674 <td class="left">Array of 4 8-bit integer values.</td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1675 </tr>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1676</table>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1677<p>Here are some examples of multidimensional arrays:</p>
1678<table class="layout">
1679 <tr class="layout">
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]1680 <td class="left"><tt>[3 x [4 x i32]]</tt></td>
1681 <td class="left">3x4 array of 32-bit integer values.</td>
1682 </tr>
1683 <tr class="layout">
1684 <td class="left"><tt>[12 x [10 x float]]</tt></td>
1685 <td class="left">12x10 array of single precision floating point values.</td>
1686 </tr>
1687 <tr class="layout">
1688 <td class="left"><tt>[2 x [3 x [4 x i16]]]</tt></td>
1689 <td class="left">2x3x4 array of 16-bit integer values.</td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1690 </tr>
1691</table>
Chris Lattnerc0ad71e2005-06-24 17:22:57 +0000[diff] [blame]1692
Dan Gohmanc74bc282009-11-09 19:01:53 +0000[diff] [blame]1693<p>There is no restriction on indexing beyond the end of the array implied by
1694 a static type (though there are restrictions on indexing beyond the bounds
1695 of an allocated object in some cases). This means that single-dimension
1696 'variable sized array' addressing can be implemented in LLVM with a zero
1697 length array type. An implementation of 'pascal style arrays' in LLVM could
1698 use the type "<tt>{ i32, [0 x float]}</tt>", for example.</p>
Chris Lattnerc0ad71e2005-06-24 17:22:57 +0000[diff] [blame]1699
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1700</div>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1701
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1702<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1703<div class="doc_subsubsection"> <a name="t_function">Function Type</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1704
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1705<div class="doc_text">
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]1706
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1707<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1708<p>The function type can be thought of as a function signature. It consists of
1709 a return type and a list of formal parameter types. The return type of a
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]1710 function type is a scalar type, a void type, a struct type, or a union
1711 type. If the return type is a struct type then all struct elements must be
1712 of first class types, and the struct must have at least one element.</p>
Devang Pateld6cff512008-03-10 20:49:15 +0000[diff] [blame]1713
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1714<h5>Syntax:</h5>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]1715<pre>
Nick Lewycky14d1ccc2009-09-27 07:55:32 +0000[diff] [blame]1716 &lt;returntype&gt; (&lt;parameter list&gt;)
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]1717</pre>
1718
John Criswell4c0cf7f2005-10-24 16:17:18 +0000[diff] [blame]1719<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]1720 specifiers. Optionally, the parameter list may include a type <tt>...</tt>,
1721 which indicates that the function takes a variable number of arguments.
1722 Variable argument functions can access their arguments with
1723 the <a href="#int_varargs">variable argument handling intrinsic</a>
Chris Lattner47f2a832010-03-02 06:36:51 +0000[diff] [blame]1724 functions. '<tt>&lt;returntype&gt;</tt>' is any type except
Nick Lewycky93e06a52009-09-27 23:27:42 +0000[diff] [blame]1725 <a href="#t_label">label</a>.</p>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]1726
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1727<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1728<table class="layout">
1729 <tr class="layout">
Reid Spencer58c08712006-12-31 07:18:34 +0000[diff] [blame]1730 <td class="left"><tt>i32 (i32)</tt></td>
1731 <td class="left">function taking an <tt>i32</tt>, returning an <tt>i32</tt>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1732 </td>
Reid Spencer58c08712006-12-31 07:18:34 +0000[diff] [blame]1733 </tr><tr class="layout">
Chris Lattner47f2a832010-03-02 06:36:51 +0000[diff] [blame]1734 <td class="left"><tt>float&nbsp;(i16,&nbsp;i32&nbsp;*)&nbsp;*
Reid Spencer655dcc62006-12-31 07:20:23 +0000[diff] [blame]1735 </tt></td>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]1736 <td class="left"><a href="#t_pointer">Pointer</a> to a function that takes
Chris Lattner47f2a832010-03-02 06:36:51 +0000[diff] [blame]1737 an <tt>i16</tt> and a <a href="#t_pointer">pointer</a> to <tt>i32</tt>,
1738 returning <tt>float</tt>.
Reid Spencer58c08712006-12-31 07:18:34 +0000[diff] [blame]1739 </td>
1740 </tr><tr class="layout">
1741 <td class="left"><tt>i32 (i8*, ...)</tt></td>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]1742 <td class="left">A vararg function that takes at least one
1743 <a href="#t_pointer">pointer</a> to <tt>i8 </tt> (char in C),
1744 which returns an integer. This is the signature for <tt>printf</tt> in
Reid Spencer58c08712006-12-31 07:18:34 +0000[diff] [blame]1745 LLVM.
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1746 </td>
Devang Patele3dfc1c2008-03-24 05:35:41 +0000[diff] [blame]1747 </tr><tr class="layout">
1748 <td class="left"><tt>{i32, i32} (i32)</tt></td>
Nick Lewycky14d1ccc2009-09-27 07:55:32 +0000[diff] [blame]1749 <td class="left">A function taking an <tt>i32</tt>, returning a
1750 <a href="#t_struct">structure</a> containing two <tt>i32</tt> values
Devang Patele3dfc1c2008-03-24 05:35:41 +0000[diff] [blame]1751 </td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1752 </tr>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1753</table>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]1754
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1755</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1756
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1757<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1758<div class="doc_subsubsection"> <a name="t_struct">Structure Type</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1759
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1760<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1761
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1762<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1763<p>The structure type is used to represent a collection of data members together
1764 in memory. The packing of the field types is defined to match the ABI of the
1765 underlying processor. The elements of a structure may be any type that has a
1766 size.</p>
1767
Jeffrey Yasskinf991bbb2010-01-11 19:19:26 +0000[diff] [blame]1768<p>Structures in memory are accessed using '<tt><a href="#i_load">load</a></tt>'
1769 and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a field
1770 with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.
1771 Structures in registers are accessed using the
1772 '<tt><a href="#i_extractvalue">extractvalue</a></tt>' and
1773 '<tt><a href="#i_insertvalue">insertvalue</a></tt>' instructions.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1774<h5>Syntax:</h5>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1775<pre>
1776 { &lt;type list&gt; }
1777</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1778
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1779<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1780<table class="layout">
1781 <tr class="layout">
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]1782 <td class="left"><tt>{ i32, i32, i32 }</tt></td>
1783 <td class="left">A triple of three <tt>i32</tt> values</td>
1784 </tr><tr class="layout">
1785 <td class="left"><tt>{&nbsp;float,&nbsp;i32&nbsp;(i32)&nbsp;*&nbsp;}</tt></td>
1786 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1787 second element is a <a href="#t_pointer">pointer</a> to a
1788 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1789 an <tt>i32</tt>.</td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1790 </tr>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1791</table>
Dan Gohman142ccc02009-01-24 15:58:40 +0000[diff] [blame]1792
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1793</div>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1794
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1795<!-- _______________________________________________________________________ -->
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]1796<div class="doc_subsubsection"> <a name="t_pstruct">Packed Structure Type</a>
1797</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1798
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]1799<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1800
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]1801<h5>Overview:</h5>
1802<p>The packed structure type is used to represent a collection of data members
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1803 together in memory. There is no padding between fields. Further, the
1804 alignment of a packed structure is 1 byte. The elements of a packed
1805 structure may be any type that has a size.</p>
1806
1807<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt> and
1808 '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a field with
1809 the '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
1810
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]1811<h5>Syntax:</h5>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1812<pre>
1813 &lt; { &lt;type list&gt; } &gt;
1814</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1815
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]1816<h5>Examples:</h5>
1817<table class="layout">
1818 <tr class="layout">
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]1819 <td class="left"><tt>&lt; { i32, i32, i32 } &gt;</tt></td>
1820 <td class="left">A triple of three <tt>i32</tt> values</td>
1821 </tr><tr class="layout">
Bill Wendlingb175fa42008-09-07 10:26:33 +0000[diff] [blame]1822 <td class="left">
1823<tt>&lt;&nbsp;{&nbsp;float,&nbsp;i32&nbsp;(i32)*&nbsp;}&nbsp;&gt;</tt></td>
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]1824 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1825 second element is a <a href="#t_pointer">pointer</a> to a
1826 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1827 an <tt>i32</tt>.</td>
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]1828 </tr>
1829</table>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1830
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]1831</div>
1832
1833<!-- _______________________________________________________________________ -->
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]1834<div class="doc_subsubsection"> <a name="t_union">Union Type</a> </div>
1835
1836<div class="doc_text">
1837
1838<h5>Overview:</h5>
1839<p>A union type describes an object with size and alignment suitable for
1840 an object of any one of a given set of types (also known as an "untagged"
1841 union). It is similar in concept and usage to a
1842 <a href="#t_struct">struct</a>, except that all members of the union
1843 have an offset of zero. The elements of a union may be any type that has a
1844 size. Unions must have at least one member - empty unions are not allowed.
1845 </p>
1846
1847<p>The size of the union as a whole will be the size of its largest member,
1848 and the alignment requirements of the union as a whole will be the largest
1849 alignment requirement of any member.</p>
1850
Dan Gohman1ad14992010-02-25 16:51:31 +0000[diff] [blame]1851<p>Union members are accessed using '<tt><a href="#i_load">load</a></tt> and
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]1852 '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a field with
1853 the '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.
1854 Since all members are at offset zero, the getelementptr instruction does
1855 not affect the address, only the type of the resulting pointer.</p>
1856
1857<h5>Syntax:</h5>
1858<pre>
1859 union { &lt;type list&gt; }
1860</pre>
1861
1862<h5>Examples:</h5>
1863<table class="layout">
1864 <tr class="layout">
1865 <td class="left"><tt>union { i32, i32*, float }</tt></td>
1866 <td class="left">A union of three types: an <tt>i32</tt>, a pointer to
1867 an <tt>i32</tt>, and a <tt>float</tt>.</td>
1868 </tr><tr class="layout">
1869 <td class="left">
1870 <tt>union {&nbsp;float,&nbsp;i32&nbsp;(i32)&nbsp;*&nbsp;}</tt></td>
1871 <td class="left">A union, where the first element is a <tt>float</tt> and the
1872 second element is a <a href="#t_pointer">pointer</a> to a
1873 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1874 an <tt>i32</tt>.</td>
1875 </tr>
1876</table>
1877
1878</div>
1879
1880<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1881<div class="doc_subsubsection"> <a name="t_pointer">Pointer Type</a> </div>
Chris Lattner4a67c912009-02-08 19:53:29 +0000[diff] [blame]1882
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1883<div class="doc_text">
1884
1885<h5>Overview:</h5>
Dan Gohman88481112010-02-25 16:50:07 +0000[diff] [blame]1886<p>The pointer type is used to specify memory locations.
1887 Pointers are commonly used to reference objects in memory.</p>
1888
1889<p>Pointer types may have an optional address space attribute defining the
1890 numbered address space where the pointed-to object resides. The default
1891 address space is number zero. The semantics of non-zero address
1892 spaces are target-specific.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1893
1894<p>Note that LLVM does not permit pointers to void (<tt>void*</tt>) nor does it
1895 permit pointers to labels (<tt>label*</tt>). Use <tt>i8*</tt> instead.</p>
Chris Lattner4a67c912009-02-08 19:53:29 +0000[diff] [blame]1896
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]1897<h5>Syntax:</h5>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1898<pre>
1899 &lt;type&gt; *
1900</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1901
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]1902<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1903<table class="layout">
1904 <tr class="layout">
Dan Gohman623806e2009-01-04 23:44:43 +0000[diff] [blame]1905 <td class="left"><tt>[4 x i32]*</tt></td>
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]1906 <td class="left">A <a href="#t_pointer">pointer</a> to <a
1907 href="#t_array">array</a> of four <tt>i32</tt> values.</td>
1908 </tr>
1909 <tr class="layout">
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]1910 <td class="left"><tt>i32 (i32*) *</tt></td>
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]1911 <td class="left"> A <a href="#t_pointer">pointer</a> to a <a
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1912 href="#t_function">function</a> that takes an <tt>i32*</tt>, returning an
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]1913 <tt>i32</tt>.</td>
1914 </tr>
1915 <tr class="layout">
1916 <td class="left"><tt>i32 addrspace(5)*</tt></td>
1917 <td class="left">A <a href="#t_pointer">pointer</a> to an <tt>i32</tt> value
1918 that resides in address space #5.</td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1919 </tr>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1920</table>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1921
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1922</div>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1923
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1924<!-- _______________________________________________________________________ -->
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]1925<div class="doc_subsubsection"> <a name="t_vector">Vector Type</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1926
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1927<div class="doc_text">
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1928
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1929<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1930<p>A vector type is a simple derived type that represents a vector of elements.
1931 Vector types are used when multiple primitive data are operated in parallel
1932 using a single instruction (SIMD). A vector type requires a size (number of
Duncan Sands31c0e0e2009-11-27 13:38:03 +0000[diff] [blame]1933 elements) and an underlying primitive data type. Vector types are considered
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1934 <a href="#t_firstclass">first class</a>.</p>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1935
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1936<h5>Syntax:</h5>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1937<pre>
1938 &lt; &lt;# elements&gt; x &lt;elementtype&gt; &gt;
1939</pre>
1940
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1941<p>The number of elements is a constant integer value; elementtype may be any
1942 integer or floating point type.</p>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1943
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1944<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1945<table class="layout">
1946 <tr class="layout">
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]1947 <td class="left"><tt>&lt;4 x i32&gt;</tt></td>
1948 <td class="left">Vector of 4 32-bit integer values.</td>
1949 </tr>
1950 <tr class="layout">
1951 <td class="left"><tt>&lt;8 x float&gt;</tt></td>
1952 <td class="left">Vector of 8 32-bit floating-point values.</td>
1953 </tr>
1954 <tr class="layout">
1955 <td class="left"><tt>&lt;2 x i64&gt;</tt></td>
1956 <td class="left">Vector of 2 64-bit integer values.</td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1957 </tr>
1958</table>
Dan Gohman142ccc02009-01-24 15:58:40 +0000[diff] [blame]1959
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1960</div>
1961
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1962<!-- _______________________________________________________________________ -->
1963<div class="doc_subsubsection"> <a name="t_opaque">Opaque Type</a> </div>
1964<div class="doc_text">
1965
1966<h5>Overview:</h5>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1967<p>Opaque types are used to represent unknown types in the system. This
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1968 corresponds (for example) to the C notion of a forward declared structure
1969 type. In LLVM, opaque types can eventually be resolved to any type (not just
1970 a structure type).</p>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1971
1972<h5>Syntax:</h5>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1973<pre>
1974 opaque
1975</pre>
1976
1977<h5>Examples:</h5>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1978<table class="layout">
1979 <tr class="layout">
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]1980 <td class="left"><tt>opaque</tt></td>
1981 <td class="left">An opaque type.</td>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1982 </tr>
1983</table>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1984
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1985</div>
1986
Chris Lattnercf7a5842009-02-02 07:32:36 +0000[diff] [blame]1987<!-- ======================================================================= -->
1988<div class="doc_subsection">
1989 <a name="t_uprefs">Type Up-references</a>
1990</div>
1991
1992<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1993
Chris Lattnercf7a5842009-02-02 07:32:36 +0000[diff] [blame]1994<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1995<p>An "up reference" allows you to refer to a lexically enclosing type without
1996 requiring it to have a name. For instance, a structure declaration may
1997 contain a pointer to any of the types it is lexically a member of. Example
1998 of up references (with their equivalent as named type declarations)
1999 include:</p>
Chris Lattnercf7a5842009-02-02 07:32:36 +0000[diff] [blame]2000
2001<pre>
Chris Lattnerbf1d5452009-02-09 10:00:56 +0000[diff] [blame]2002 { \2 * } %x = type { %x* }
Chris Lattnercf7a5842009-02-02 07:32:36 +0000[diff] [blame]2003 { \2 }* %y = type { %y }*
2004 \1* %z = type %z*
2005</pre>
2006
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2007<p>An up reference is needed by the asmprinter for printing out cyclic types
2008 when there is no declared name for a type in the cycle. Because the
2009 asmprinter does not want to print out an infinite type string, it needs a
2010 syntax to handle recursive types that have no names (all names are optional
2011 in llvm IR).</p>
Chris Lattnercf7a5842009-02-02 07:32:36 +0000[diff] [blame]2012
2013<h5>Syntax:</h5>
2014<pre>
2015 \&lt;level&gt;
2016</pre>
2017
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2018<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]2019
2020<h5>Examples:</h5>
Chris Lattnercf7a5842009-02-02 07:32:36 +0000[diff] [blame]2021<table class="layout">
2022 <tr class="layout">
2023 <td class="left"><tt>\1*</tt></td>
2024 <td class="left">Self-referential pointer.</td>
2025 </tr>
2026 <tr class="layout">
2027 <td class="left"><tt>{ { \3*, i8 }, i32 }</tt></td>
2028 <td class="left">Recursive structure where the upref refers to the out-most
2029 structure.</td>
2030 </tr>
2031</table>
Chris Lattnercf7a5842009-02-02 07:32:36 +0000[diff] [blame]2032
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2033</div>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]2034
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2035<!-- *********************************************************************** -->
2036<div class="doc_section"> <a name="constants">Constants</a> </div>
2037<!-- *********************************************************************** -->
2038
2039<div class="doc_text">
2040
2041<p>LLVM has several different basic types of constants. This section describes
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2042 them all and their syntax.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2043
2044</div>
2045
2046<!-- ======================================================================= -->
Reid Spencer8f08d802004-12-09 18:02:53 +0000[diff] [blame]2047<div class="doc_subsection"><a name="simpleconstants">Simple Constants</a></div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2048
2049<div class="doc_text">
2050
2051<dl>
2052 <dt><b>Boolean constants</b></dt>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2053 <dd>The two strings '<tt>true</tt>' and '<tt>false</tt>' are both valid
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]2054 constants of the <tt><a href="#t_integer">i1</a></tt> type.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2055
2056 <dt><b>Integer constants</b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2057 <dd>Standard integers (such as '4') are constants of
2058 the <a href="#t_integer">integer</a> type. Negative numbers may be used
2059 with integer types.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2060
2061 <dt><b>Floating point constants</b></dt>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2062 <dd>Floating point constants use standard decimal notation (e.g. 123.421),
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2063 exponential notation (e.g. 1.23421e+2), or a more precise hexadecimal
2064 notation (see below). The assembler requires the exact decimal value of a
2065 floating-point constant. For example, the assembler accepts 1.25 but
2066 rejects 1.3 because 1.3 is a repeating decimal in binary. Floating point
2067 constants must have a <a href="#t_floating">floating point</a> type. </dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2068
2069 <dt><b>Null pointer constants</b></dt>
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]2070 <dd>The identifier '<tt>null</tt>' is recognized as a null pointer constant
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2071 and must be of <a href="#t_pointer">pointer type</a>.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2072</dl>
2073
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2074<p>The one non-intuitive notation for constants is the hexadecimal form of
2075 floating point constants. For example, the form '<tt>double
2076 0x432ff973cafa8000</tt>' is equivalent to (but harder to read than)
2077 '<tt>double 4.5e+15</tt>'. The only time hexadecimal floating point
2078 constants are required (and the only time that they are generated by the
2079 disassembler) is when a floating point constant must be emitted but it cannot
2080 be represented as a decimal floating point number in a reasonable number of
2081 digits. For example, NaN's, infinities, and other special values are
2082 represented in their IEEE hexadecimal format so that assembly and disassembly
2083 do not cause any bits to change in the constants.</p>
2084
Dale Johannesencd4a3012009-02-11 22:14:51 +0000[diff] [blame]2085<p>When using the hexadecimal form, constants of types float and double are
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2086 represented using the 16-digit form shown above (which matches the IEEE754
2087 representation for double); float values must, however, be exactly
2088 representable as IEE754 single precision. Hexadecimal format is always used
2089 for long double, and there are three forms of long double. The 80-bit format
2090 used by x86 is represented as <tt>0xK</tt> followed by 20 hexadecimal digits.
2091 The 128-bit format used by PowerPC (two adjacent doubles) is represented
2092 by <tt>0xM</tt> followed by 32 hexadecimal digits. The IEEE 128-bit format
2093 is represented by <tt>0xL</tt> followed by 32 hexadecimal digits; no
2094 currently supported target uses this format. Long doubles will only work if
2095 they match the long double format on your target. All hexadecimal formats
2096 are big-endian (sign bit at the left).</p>
2097
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2098</div>
2099
2100<!-- ======================================================================= -->
Chris Lattner361bfcd2009-02-28 18:32:25 +0000[diff] [blame]2101<div class="doc_subsection">
Bill Wendling972b7202009-07-20 02:32:41 +0000[diff] [blame]2102<a name="aggregateconstants"></a> <!-- old anchor -->
2103<a name="complexconstants">Complex Constants</a>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2104</div>
2105
2106<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2107
Chris Lattner361bfcd2009-02-28 18:32:25 +0000[diff] [blame]2108<p>Complex constants are a (potentially recursive) combination of simple
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2109 constants and smaller complex constants.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2110
2111<dl>
2112 <dt><b>Structure constants</b></dt>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2113 <dd>Structure constants are represented with notation similar to structure
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2114 type definitions (a comma separated list of elements, surrounded by braces
2115 (<tt>{}</tt>)). For example: "<tt>{ i32 4, float 17.0, i32* @G }</tt>",
2116 where "<tt>@G</tt>" is declared as "<tt>@G = external global i32</tt>".
2117 Structure constants must have <a href="#t_struct">structure type</a>, and
2118 the number and types of elements must match those specified by the
2119 type.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2120
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]2121 <dt><b>Union constants</b></dt>
2122 <dd>Union constants are represented with notation similar to a structure with
2123 a single element - that is, a single typed element surrounded
2124 by braces (<tt>{}</tt>)). For example: "<tt>{ i32 4 }</tt>". The
2125 <a href="#t_union">union type</a> can be initialized with a single-element
2126 struct as long as the type of the struct element matches the type of
2127 one of the union members.</dd>
2128
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2129 <dt><b>Array constants</b></dt>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2130 <dd>Array constants are represented with notation similar to array type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2131 definitions (a comma separated list of elements, surrounded by square
2132 brackets (<tt>[]</tt>)). For example: "<tt>[ i32 42, i32 11, i32 74
2133 ]</tt>". Array constants must have <a href="#t_array">array type</a>, and
2134 the number and types of elements must match those specified by the
2135 type.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2136
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]2137 <dt><b>Vector constants</b></dt>
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]2138 <dd>Vector constants are represented with notation similar to vector type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2139 definitions (a comma separated list of elements, surrounded by
2140 less-than/greater-than's (<tt>&lt;&gt;</tt>)). For example: "<tt>&lt; i32
2141 42, i32 11, i32 74, i32 100 &gt;</tt>". Vector constants must
2142 have <a href="#t_vector">vector type</a>, and the number and types of
2143 elements must match those specified by the type.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2144
2145 <dt><b>Zero initialization</b></dt>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2146 <dd>The string '<tt>zeroinitializer</tt>' can be used to zero initialize a
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]2147 value to zero of <em>any</em> type, including scalar and
2148 <a href="#t_aggregate">aggregate</a> types.
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2149 This is often used to avoid having to print large zero initializers
2150 (e.g. for large arrays) and is always exactly equivalent to using explicit
2151 zero initializers.</dd>
Nick Lewycky49f89192009-04-04 07:22:01 +0000[diff] [blame]2152
2153 <dt><b>Metadata node</b></dt>
Nick Lewycky8e2c4f42009-05-30 16:08:30 +0000[diff] [blame]2154 <dd>A metadata node is a structure-like constant with
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2155 <a href="#t_metadata">metadata type</a>. For example: "<tt>metadata !{
2156 i32 0, metadata !"test" }</tt>". Unlike other constants that are meant to
2157 be interpreted as part of the instruction stream, metadata is a place to
2158 attach additional information such as debug info.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2159</dl>
2160
2161</div>
2162
2163<!-- ======================================================================= -->
2164<div class="doc_subsection">
2165 <a name="globalconstants">Global Variable and Function Addresses</a>
2166</div>
2167
2168<div class="doc_text">
2169
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2170<p>The addresses of <a href="#globalvars">global variables</a>
2171 and <a href="#functionstructure">functions</a> are always implicitly valid
2172 (link-time) constants. These constants are explicitly referenced when
2173 the <a href="#identifiers">identifier for the global</a> is used and always
2174 have <a href="#t_pointer">pointer</a> type. For example, the following is a
2175 legal LLVM file:</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2176
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2177<div class="doc_code">
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2178<pre>
Chris Lattner00538a12007-06-06 18:28:13 +0000[diff] [blame]2179@X = global i32 17
2180@Y = global i32 42
2181@Z = global [2 x i32*] [ i32* @X, i32* @Y ]
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2182</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2183</div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2184
2185</div>
2186
2187<!-- ======================================================================= -->
Reid Spencer641f5c92004-12-09 18:13:12 +0000[diff] [blame]2188<div class="doc_subsection"><a name="undefvalues">Undefined Values</a></div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2189<div class="doc_text">
2190
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2191<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]2192 indicates that the user of the value may receive an unspecified bit-pattern.
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2193 Undefined values may be of any type (other than label or void) and be used
2194 anywhere a constant is permitted.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2195
Chris Lattner92ada5d2009-09-11 01:49:31 +0000[diff] [blame]2196<p>Undefined values are useful because they indicate to the compiler that the
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2197 program is well defined no matter what value is used. This gives the
2198 compiler more freedom to optimize. Here are some examples of (potentially
2199 surprising) transformations that are valid (in pseudo IR):</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2200
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2201
2202<div class="doc_code">
2203<pre>
2204 %A = add %X, undef
2205 %B = sub %X, undef
2206 %C = xor %X, undef
2207Safe:
2208 %A = undef
2209 %B = undef
2210 %C = undef
2211</pre>
2212</div>
2213
2214<p>This is safe because all of the output bits are affected by the undef bits.
2215Any output bit can have a zero or one depending on the input bits.</p>
2216
2217<div class="doc_code">
2218<pre>
2219 %A = or %X, undef
2220 %B = and %X, undef
2221Safe:
2222 %A = -1
2223 %B = 0
2224Unsafe:
2225 %A = undef
2226 %B = undef
2227</pre>
2228</div>
2229
2230<p>These logical operations have bits that are not always affected by the input.
2231For example, if "%X" has a zero bit, then the output of the 'and' operation will
2232always be a zero, no matter what the corresponding bit from the undef is. As
Chris Lattner92ada5d2009-09-11 01:49:31 +0000[diff] [blame]2233such, 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]2234However, it is safe to assume that all bits of the undef could be 0, and
2235optimize the and to 0. Likewise, it is safe to assume that all the bits of
2236the 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]2237-1.</p>
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2238
2239<div class="doc_code">
2240<pre>
2241 %A = select undef, %X, %Y
2242 %B = select undef, 42, %Y
2243 %C = select %X, %Y, undef
2244Safe:
2245 %A = %X (or %Y)
2246 %B = 42 (or %Y)
2247 %C = %Y
2248Unsafe:
2249 %A = undef
2250 %B = undef
2251 %C = undef
2252</pre>
2253</div>
2254
2255<p>This set of examples show that undefined select (and conditional branch)
2256conditions can go "either way" but they have to come from one of the two
2257operands. In the %A example, if %X and %Y were both known to have a clear low
2258bit, then %A would have to have a cleared low bit. However, in the %C example,
2259the optimizer is allowed to assume that the undef operand could be the same as
2260%Y, allowing the whole select to be eliminated.</p>
2261
2262
2263<div class="doc_code">
2264<pre>
2265 %A = xor undef, undef
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]2266
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2267 %B = undef
2268 %C = xor %B, %B
2269
2270 %D = undef
2271 %E = icmp lt %D, 4
2272 %F = icmp gte %D, 4
2273
2274Safe:
2275 %A = undef
2276 %B = undef
2277 %C = undef
2278 %D = undef
2279 %E = undef
2280 %F = undef
2281</pre>
2282</div>
2283
2284<p>This example points out that two undef operands are not necessarily the same.
2285This can be surprising to people (and also matches C semantics) where they
2286assume that "X^X" is always zero, even if X is undef. This isn't true for a
2287number of reasons, but the short answer is that an undef "variable" can
2288arbitrarily change its value over its "live range". This is true because the
2289"variable" doesn't actually <em>have a live range</em>. Instead, the value is
2290logically read from arbitrary registers that happen to be around when needed,
Benjamin Kramer0f420382009-10-12 14:46:08 +0000[diff] [blame]2291so the value is not necessarily consistent over time. In fact, %A and %C need
Chris Lattner6760e542009-09-08 15:13:16 +0000[diff] [blame]2292to have the same semantics or the core LLVM "replace all uses with" concept
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2293would not hold.</p>
Chris Lattnera34a7182009-09-07 23:33:52 +0000[diff] [blame]2294
2295<div class="doc_code">
2296<pre>
2297 %A = fdiv undef, %X
2298 %B = fdiv %X, undef
2299Safe:
2300 %A = undef
2301b: unreachable
2302</pre>
2303</div>
2304
2305<p>These examples show the crucial difference between an <em>undefined
2306value</em> and <em>undefined behavior</em>. An undefined value (like undef) is
2307allowed to have an arbitrary bit-pattern. This means that the %A operation
2308can be constant folded to undef because the undef could be an SNaN, and fdiv is
2309not (currently) defined on SNaN's. However, in the second example, we can make
2310a more aggressive assumption: because the undef is allowed to be an arbitrary
2311value, 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]2312has <em>undefined behavior</em>, we are allowed to assume that the operation
Chris Lattnera34a7182009-09-07 23:33:52 +0000[diff] [blame]2313does not execute at all. This allows us to delete the divide and all code after
2314it: since the undefined operation "can't happen", the optimizer can assume that
2315it occurs in dead code.
2316</p>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]2317
Chris Lattnera34a7182009-09-07 23:33:52 +0000[diff] [blame]2318<div class="doc_code">
2319<pre>
2320a: store undef -> %X
2321b: store %X -> undef
2322Safe:
2323a: &lt;deleted&gt;
2324b: unreachable
2325</pre>
2326</div>
2327
2328<p>These examples reiterate the fdiv example: a store "of" an undefined value
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]2329can be assumed to not have any effect: we can assume that the value is
Chris Lattnera34a7182009-09-07 23:33:52 +0000[diff] [blame]2330overwritten with bits that happen to match what was already there. However, a
2331store "to" an undefined location could clobber arbitrary memory, therefore, it
2332has undefined behavior.</p>
2333
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2334</div>
2335
2336<!-- ======================================================================= -->
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]2337<div class="doc_subsection"><a name="trapvalues">Trap Values</a></div>
2338<div class="doc_text">
2339
Dan Gohmanb2a709b2010-04-26 20:21:21 +0000[diff] [blame]2340<p>Trap values are similar to <a href="#undefvalues">undef values</a>, however
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]2341 instead of representing an unspecified bit pattern, they represent the
2342 fact that an instruction or constant expression which cannot evoke side
2343 effects has nevertheless detected a condition which results in undefined
Dan Gohmanb2a709b2010-04-26 20:21:21 +0000[diff] [blame]2344 behavior.</p>
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]2345
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2346<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]2347 only exist when produced by operations such as
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2348 <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]2349
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2350<p>Trap value behavior is defined in terms of value <i>dependence</i>:</p>
Dan Gohmanb8b85c12010-04-26 23:36:52 +0000[diff] [blame]2351
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2352<p>
2353<ul>
2354<li>Values other than <a href="#i_phi"><tt>phi</tt></a> nodes depend on
2355 their operands.</li>
2356
2357<li><a href="#i_phi"><tt>Phi</tt></a> nodes depend on the operand corresponding
2358 to their dynamic predecessor basic block.</li>
2359
2360<li>Function arguments depend on the corresponding actual argument values in
2361 the dynamic callers of their functions.</li>
2362
2363<li><a href="#i_call"><tt>Call</tt></a> instructions depend on the
2364 <a href="#i_ret"><tt>ret</tt></a> instructions that dynamically transfer
2365 control back to them.</li>
2366
Dan Gohman7292a752010-05-03 14:55:22 +0000[diff] [blame]2367<li><a href="#i_invoke"><tt>Invoke</tt></a> instructions depend on the
2368 <a href="#i_ret"><tt>ret</tt></a>, <a href="#i_unwind"><tt>unwind</tt></a>,
2369 or exception-throwing call instructions that dynamically transfer control
2370 back to them.</li>
2371
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2372<li>Non-volatile loads and stores depend on the most recent stores to all of the
2373 referenced memory addresses, following the order in the IR
2374 (including loads and stores implied by intrinsics such as
2375 <a href="#int_memcpy"><tt>@llvm.memcpy</tt></a>.)</li>
2376
Dan Gohman3513ea52010-05-03 14:59:34 +0000[diff] [blame]2377<!-- TODO: In the case of multiple threads, this only applies if the store
2378 "happens-before" the load or store. -->
Dan Gohmanb8b85c12010-04-26 23:36:52 +0000[diff] [blame]2379
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2380<!-- TODO: floating-point exception state -->
Dan Gohmanb8b85c12010-04-26 23:36:52 +0000[diff] [blame]2381
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2382<li>An instruction with externally visible side effects depends on the most
2383 recent preceding instruction with externally visible side effects, following
2384 the order in the IR. (This includes volatile loads and stores.)</li>
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]2385
Dan Gohman7292a752010-05-03 14:55:22 +0000[diff] [blame]2386<li>An instruction <i>control-depends</i> on a
2387 <a href="#terminators">terminator instruction</a>
2388 if the terminator instruction has multiple successors and the instruction
2389 is always executed when control transfers to one of the successors, and
2390 may not be executed when control is transfered to another.</li>
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2391
2392<li>Dependence is transitive.</li>
2393
2394</ul>
2395</p>
2396
2397<p>Whenever a trap value is generated, all values which depend on it evaluate
2398 to trap. If they have side effects, the evoke their side effects as if each
2399 operand with a trap value were undef. If they have externally-visible side
2400 effects, the behavior is undefined.</p>
2401
2402<p>Here are some examples:</p>
Dan Gohman48a25882010-04-26 20:54:53 +0000[diff] [blame]2403
Dan Gohmanb8b85c12010-04-26 23:36:52 +0000[diff] [blame]2404<div class="doc_code">
2405<pre>
2406entry:
2407 %trap = sub nuw i32 0, 1 ; Results in a trap value.
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2408 %still_trap = and i32 %trap, 0 ; Whereas (and i32 undef, 0) would return 0.
2409 %trap_yet_again = getelementptr i32* @h, i32 %still_trap
2410 store i32 0, i32* %trap_yet_again ; undefined behavior
2411
2412 store i32 %trap, i32* @g ; Trap value conceptually stored to memory.
2413 %trap2 = load i32* @g ; Returns a trap value, not just undef.
2414
2415 volatile store i32 %trap, i32* @g ; External observation; undefined behavior.
2416
2417 %narrowaddr = bitcast i32* @g to i16*
2418 %wideaddr = bitcast i32* @g to i64*
2419 %trap3 = load 16* %narrowaddr ; Returns a trap value.
2420 %trap4 = load i64* %widaddr ; Returns a trap value.
2421
2422 %cmp = icmp i32 slt %trap, 0 ; Returns a trap value.
Dan Gohmanb8b85c12010-04-26 23:36:52 +0000[diff] [blame]2423 %br i1 %cmp, %true, %end ; Branch to either destination.
2424
2425true:
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2426 volatile store i32 0, i32* @g ; This is control-dependent on %cmp, so
2427 ; it has undefined behavior.
Dan Gohmanb8b85c12010-04-26 23:36:52 +0000[diff] [blame]2428 br label %end
2429
2430end:
2431 %p = phi i32 [ 0, %entry ], [ 1, %true ]
2432 ; Both edges into this PHI are
2433 ; control-dependent on %cmp, so this
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2434 ; always results in a trap value.
Dan Gohmanb8b85c12010-04-26 23:36:52 +0000[diff] [blame]2435
2436 volatile store i32 0, i32* @g ; %end is control-equivalent to %entry
2437 ; so this is defined (ignoring earlier
2438 ; undefined behavior in this example).
Dan Gohmanb8b85c12010-04-26 23:36:52 +0000[diff] [blame]2439</pre>
2440</div>
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]2441
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]2442</div>
2443
2444<!-- ======================================================================= -->
Chris Lattner2bfd3202009-10-27 21:19:13 +0000[diff] [blame]2445<div class="doc_subsection"><a name="blockaddress">Addresses of Basic
2446 Blocks</a></div>
Chris Lattnere4801f72009-10-27 21:01:34 +0000[diff] [blame]2447<div class="doc_text">
2448
Chris Lattneraa99c942009-11-01 01:27:45 +0000[diff] [blame]2449<p><b><tt>blockaddress(@function, %block)</tt></b></p>
Chris Lattnere4801f72009-10-27 21:01:34 +0000[diff] [blame]2450
2451<p>The '<tt>blockaddress</tt>' constant computes the address of the specified
Chris Lattner5c5f0ac2009-10-27 21:49:40 +0000[diff] [blame]2452 basic block in the specified function, and always has an i8* type. Taking
Chris Lattneraa99c942009-11-01 01:27:45 +0000[diff] [blame]2453 the address of the entry block is illegal.</p>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]2454
Chris Lattnere4801f72009-10-27 21:01:34 +0000[diff] [blame]2455<p>This value only has defined behavior when used as an operand to the
Chris Lattnerd04cb6d2009-10-28 00:19:10 +0000[diff] [blame]2456 '<a href="#i_indirectbr"><tt>indirectbr</tt></a>' instruction or for comparisons
Chris Lattnere4801f72009-10-27 21:01:34 +0000[diff] [blame]2457 against null. Pointer equality tests between labels addresses is undefined
2458 behavior - though, again, comparison against null is ok, and no label is
Chris Lattner2bfd3202009-10-27 21:19:13 +0000[diff] [blame]2459 equal to the null pointer. This may also be passed around as an opaque
2460 pointer sized value as long as the bits are not inspected. This allows
Chris Lattnerda37b302009-10-27 21:44:20 +0000[diff] [blame]2461 <tt>ptrtoint</tt> and arithmetic to be performed on these values so long as
Chris Lattnerd04cb6d2009-10-28 00:19:10 +0000[diff] [blame]2462 the original value is reconstituted before the <tt>indirectbr</tt>.</p>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]2463
Chris Lattner2bfd3202009-10-27 21:19:13 +0000[diff] [blame]2464<p>Finally, some targets may provide defined semantics when
Chris Lattnere4801f72009-10-27 21:01:34 +0000[diff] [blame]2465 using the value as the operand to an inline assembly, but that is target
2466 specific.
2467 </p>
2468
2469</div>
2470
2471
2472<!-- ======================================================================= -->
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2473<div class="doc_subsection"><a name="constantexprs">Constant Expressions</a>
2474</div>
2475
2476<div class="doc_text">
2477
2478<p>Constant expressions are used to allow expressions involving other constants
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2479 to be used as constants. Constant expressions may be of
2480 any <a href="#t_firstclass">first class</a> type and may involve any LLVM
2481 operation that does not have side effects (e.g. load and call are not
2482 supported). The following is the syntax for constant expressions:</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2483
2484<dl>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2485 <dt><b><tt>trunc (CST to TYPE)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2486 <dd>Truncate a constant to another type. The bit size of CST must be larger
2487 than the bit size of TYPE. Both types must be integers.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2488
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2489 <dt><b><tt>zext (CST to TYPE)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2490 <dd>Zero extend a constant to another type. The bit size of CST must be
2491 smaller or equal to the bit size of TYPE. Both types must be
2492 integers.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2493
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2494 <dt><b><tt>sext (CST to TYPE)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2495 <dd>Sign extend a constant to another type. The bit size of CST must be
2496 smaller or equal to the bit size of TYPE. Both types must be
2497 integers.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2498
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2499 <dt><b><tt>fptrunc (CST to TYPE)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2500 <dd>Truncate a floating point constant to another floating point type. The
2501 size of CST must be larger than the size of TYPE. Both types must be
2502 floating point.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2503
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2504 <dt><b><tt>fpext (CST to TYPE)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2505 <dd>Floating point extend a constant to another type. The size of CST must be
2506 smaller or equal to the size of TYPE. Both types must be floating
2507 point.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2508
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2509 <dt><b><tt>fptoui (CST to TYPE)</tt></b></dt>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2510 <dd>Convert a floating point constant to the corresponding unsigned integer
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2511 constant. TYPE must be a scalar or vector integer type. CST must be of
2512 scalar or vector floating point type. Both CST and TYPE must be scalars,
2513 or vectors of the same number of elements. If the value won't fit in the
2514 integer type, the results are undefined.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2515
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2516 <dt><b><tt>fptosi (CST to TYPE)</tt></b></dt>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2517 <dd>Convert a floating point constant to the corresponding signed integer
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2518 constant. TYPE must be a scalar or vector integer type. CST must be of
2519 scalar or vector floating point type. Both CST and TYPE must be scalars,
2520 or vectors of the same number of elements. If the value won't fit in the
2521 integer type, the results are undefined.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2522
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2523 <dt><b><tt>uitofp (CST to TYPE)</tt></b></dt>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2524 <dd>Convert an unsigned integer constant to the corresponding floating point
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2525 constant. TYPE must be a scalar or vector floating point type. CST must be
2526 of scalar or vector integer type. Both CST and TYPE must be scalars, or
2527 vectors of the same number of elements. If the value won't fit in the
2528 floating point type, the results are undefined.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2529
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2530 <dt><b><tt>sitofp (CST to TYPE)</tt></b></dt>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2531 <dd>Convert a signed integer constant to the corresponding floating point
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2532 constant. TYPE must be a scalar or vector floating point type. CST must be
2533 of scalar or vector integer type. Both CST and TYPE must be scalars, or
2534 vectors of the same number of elements. If the value won't fit in the
2535 floating point type, the results are undefined.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2536
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2537 <dt><b><tt>ptrtoint (CST to TYPE)</tt></b></dt>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]2538 <dd>Convert a pointer typed constant to the corresponding integer constant
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2539 <tt>TYPE</tt> must be an integer type. <tt>CST</tt> must be of pointer
2540 type. The <tt>CST</tt> value is zero extended, truncated, or unchanged to
2541 make it fit in <tt>TYPE</tt>.</dd>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]2542
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2543 <dt><b><tt>inttoptr (CST to TYPE)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2544 <dd>Convert a integer constant to a pointer constant. TYPE must be a pointer
2545 type. CST must be of integer type. The CST value is zero extended,
2546 truncated, or unchanged to make it fit in a pointer size. This one is
2547 <i>really</i> dangerous!</dd>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]2548
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2549 <dt><b><tt>bitcast (CST to TYPE)</tt></b></dt>
Chris Lattner789dee32009-02-28 18:27:03 +0000[diff] [blame]2550 <dd>Convert a constant, CST, to another TYPE. The constraints of the operands
2551 are the same as those for the <a href="#i_bitcast">bitcast
2552 instruction</a>.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2553
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2554 <dt><b><tt>getelementptr (CSTPTR, IDX0, IDX1, ...)</tt></b></dt>
2555 <dt><b><tt>getelementptr inbounds (CSTPTR, IDX0, IDX1, ...)</tt></b></dt>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2556 <dd>Perform the <a href="#i_getelementptr">getelementptr operation</a> on
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2557 constants. As with the <a href="#i_getelementptr">getelementptr</a>
2558 instruction, the index list may have zero or more indexes, which are
2559 required to make sense for the type of "CSTPTR".</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2560
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2561 <dt><b><tt>select (COND, VAL1, VAL2)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2562 <dd>Perform the <a href="#i_select">select operation</a> on constants.</dd>
Reid Spencer9965ee72006-12-04 19:23:19 +0000[diff] [blame]2563
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2564 <dt><b><tt>icmp COND (VAL1, VAL2)</tt></b></dt>
Reid Spencer9965ee72006-12-04 19:23:19 +0000[diff] [blame]2565 <dd>Performs the <a href="#i_icmp">icmp operation</a> on constants.</dd>
2566
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2567 <dt><b><tt>fcmp COND (VAL1, VAL2)</tt></b></dt>
Reid Spencer9965ee72006-12-04 19:23:19 +0000[diff] [blame]2568 <dd>Performs the <a href="#i_fcmp">fcmp operation</a> on constants.</dd>
Robert Bocchino7e97a6d2006-01-10 19:31:34 +0000[diff] [blame]2569
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2570 <dt><b><tt>extractelement (VAL, IDX)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2571 <dd>Perform the <a href="#i_extractelement">extractelement operation</a> on
2572 constants.</dd>
Robert Bocchino7e97a6d2006-01-10 19:31:34 +0000[diff] [blame]2573
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2574 <dt><b><tt>insertelement (VAL, ELT, IDX)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2575 <dd>Perform the <a href="#i_insertelement">insertelement operation</a> on
2576 constants.</dd>
Chris Lattner016a0e52006-04-08 00:13:41 +0000[diff] [blame]2577
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2578 <dt><b><tt>shufflevector (VEC1, VEC2, IDXMASK)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2579 <dd>Perform the <a href="#i_shufflevector">shufflevector operation</a> on
2580 constants.</dd>
Chris Lattner016a0e52006-04-08 00:13:41 +0000[diff] [blame]2581
Nick Lewycky9ab9a7f2010-05-29 06:44:15 +0000[diff] [blame]2582 <dt><b><tt>extractvalue (VAL, IDX0, IDX1, ...)</tt></b></dt>
2583 <dd>Perform the <a href="#i_extractvalue">extractvalue operation</a> on
2584 constants. The index list is interpreted in a similar manner as indices in
2585 a '<a href="#i_getelementptr">getelementptr</a>' operation. At least one
2586 index value must be specified.</dd>
2587
2588 <dt><b><tt>insertvalue (VAL, ELT, IDX0, IDX1, ...)</tt></b></dt>
2589 <dd>Perform the <a href="#i_insertvalue">insertvalue operation</a> on
2590 constants. The index list is interpreted in a similar manner as indices in
2591 a '<a href="#i_getelementptr">getelementptr</a>' operation. At least one
2592 index value must be specified.</dd>
2593
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2594 <dt><b><tt>OPCODE (LHS, RHS)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2595 <dd>Perform the specified operation of the LHS and RHS constants. OPCODE may
2596 be any of the <a href="#binaryops">binary</a>
2597 or <a href="#bitwiseops">bitwise binary</a> operations. The constraints
2598 on operands are the same as those for the corresponding instruction
2599 (e.g. no bitwise operations on floating point values are allowed).</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2600</dl>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2601
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2602</div>
Chris Lattnerb1652612004-03-08 16:49:10 +0000[diff] [blame]2603
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2604<!-- *********************************************************************** -->
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2605<div class="doc_section"> <a name="othervalues">Other Values</a> </div>
2606<!-- *********************************************************************** -->
2607
2608<!-- ======================================================================= -->
2609<div class="doc_subsection">
2610<a name="inlineasm">Inline Assembler Expressions</a>
2611</div>
2612
2613<div class="doc_text">
2614
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2615<p>LLVM supports inline assembler expressions (as opposed
2616 to <a href="#moduleasm"> Module-Level Inline Assembly</a>) through the use of
2617 a special value. This value represents the inline assembler as a string
2618 (containing the instructions to emit), a list of operand constraints (stored
Dale Johannesen63c94fe2009-10-13 21:56:55 +0000[diff] [blame]2619 as a string), a flag that indicates whether or not the inline asm
Dale Johannesen1cfb9582009-10-21 23:28:00 +0000[diff] [blame]2620 expression has side effects, and a flag indicating whether the function
2621 containing the asm needs to align its stack conservatively. An example
2622 inline assembler expression is:</p>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2623
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2624<div class="doc_code">
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2625<pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2626i32 (i32) asm "bswap $0", "=r,r"
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2627</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2628</div>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2629
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2630<p>Inline assembler expressions may <b>only</b> be used as the callee operand of
2631 a <a href="#i_call"><tt>call</tt> instruction</a>. Thus, typically we
2632 have:</p>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2633
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2634<div class="doc_code">
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2635<pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2636%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]2637</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2638</div>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2639
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2640<p>Inline asms with side effects not visible in the constraint list must be
2641 marked as having side effects. This is done through the use of the
2642 '<tt>sideeffect</tt>' keyword, like so:</p>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2643
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2644<div class="doc_code">
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2645<pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2646call void asm sideeffect "eieio", ""()
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2647</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2648</div>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2649
Dale Johannesen1cfb9582009-10-21 23:28:00 +0000[diff] [blame]2650<p>In some cases inline asms will contain code that will not work unless the
2651 stack is aligned in some way, such as calls or SSE instructions on x86,
2652 yet will not contain code that does that alignment within the asm.
2653 The compiler should make conservative assumptions about what the asm might
2654 contain and should generate its usual stack alignment code in the prologue
2655 if the '<tt>alignstack</tt>' keyword is present:</p>
Dale Johannesen63c94fe2009-10-13 21:56:55 +0000[diff] [blame]2656
2657<div class="doc_code">
2658<pre>
Dale Johannesen1cfb9582009-10-21 23:28:00 +0000[diff] [blame]2659call void asm alignstack "eieio", ""()
Dale Johannesen63c94fe2009-10-13 21:56:55 +0000[diff] [blame]2660</pre>
2661</div>
2662
2663<p>If both keywords appear the '<tt>sideeffect</tt>' keyword must come
2664 first.</p>
2665
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2666<p>TODO: The format of the asm and constraints string still need to be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2667 documented here. Constraints on what can be done (e.g. duplication, moving,
2668 etc need to be documented). This is probably best done by reference to
2669 another document that covers inline asm from a holistic perspective.</p>
Chris Lattner51065562010-04-07 05:38:05 +0000[diff] [blame]2670</div>
2671
2672<div class="doc_subsubsection">
2673<a name="inlineasm_md">Inline Asm Metadata</a>
2674</div>
2675
2676<div class="doc_text">
2677
2678<p>The call instructions that wrap inline asm nodes may have a "!srcloc" MDNode
2679 attached to it that contains a constant integer. If present, the code
2680 generator will use the integer as the location cookie value when report
2681 errors through the LLVMContext error reporting mechanisms. This allows a
Dan Gohman61110ae2010-04-28 00:36:01 +0000[diff] [blame]2682 front-end to correlate backend errors that occur with inline asm back to the
Chris Lattner51065562010-04-07 05:38:05 +0000[diff] [blame]2683 source code that produced it. For example:</p>
2684
2685<div class="doc_code">
2686<pre>
2687call void asm sideeffect "something bad", ""()<b>, !srcloc !42</b>
2688...
2689!42 = !{ i32 1234567 }
2690</pre>
2691</div>
2692
2693<p>It is up to the front-end to make sense of the magic numbers it places in the
2694 IR.</p>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2695
2696</div>
2697
Chris Lattnerc2f8f162010-01-15 21:50:19 +0000[diff] [blame]2698<!-- ======================================================================= -->
2699<div class="doc_subsection"><a name="metadata">Metadata Nodes and Metadata
2700 Strings</a>
2701</div>
2702
2703<div class="doc_text">
2704
2705<p>LLVM IR allows metadata to be attached to instructions in the program that
2706 can convey extra information about the code to the optimizers and code
2707 generator. One example application of metadata is source-level debug
2708 information. There are two metadata primitives: strings and nodes. All
2709 metadata has the <tt>metadata</tt> type and is identified in syntax by a
2710 preceding exclamation point ('<tt>!</tt>').</p>
2711
2712<p>A metadata string is a string surrounded by double quotes. It can contain
2713 any character by escaping non-printable characters with "\xx" where "xx" is
2714 the two digit hex code. For example: "<tt>!"test\00"</tt>".</p>
2715
2716<p>Metadata nodes are represented with notation similar to structure constants
2717 (a comma separated list of elements, surrounded by braces and preceded by an
2718 exclamation point). For example: "<tt>!{ metadata !"test\00", i32
2719 10}</tt>". Metadata nodes can have any values as their operand.</p>
2720
2721<p>A <a href="#namedmetadatastructure">named metadata</a> is a collection of
2722 metadata nodes, which can be looked up in the module symbol table. For
2723 example: "<tt>!foo = metadata !{!4, !3}</tt>".
2724
Devang Patel9984bd62010-03-04 23:44:48 +0000[diff] [blame]2725<p>Metadata can be used as function arguments. Here <tt>llvm.dbg.value</tt>
2726 function is using two metadata arguments.
2727
2728 <div class="doc_code">
2729 <pre>
2730 call void @llvm.dbg.value(metadata !24, i64 0, metadata !25)
2731 </pre>
2732 </div></p>
2733
2734<p>Metadata can be attached with an instruction. Here metadata <tt>!21</tt> is
2735 attached with <tt>add</tt> instruction using <tt>!dbg</tt> identifier.
2736
2737 <div class="doc_code">
2738 <pre>
2739 %indvar.next = add i64 %indvar, 1, !dbg !21
2740 </pre>
2741 </div></p>
Chris Lattnerc2f8f162010-01-15 21:50:19 +0000[diff] [blame]2742</div>
2743
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]2744
2745<!-- *********************************************************************** -->
2746<div class="doc_section">
2747 <a name="intrinsic_globals">Intrinsic Global Variables</a>
2748</div>
2749<!-- *********************************************************************** -->
2750
2751<p>LLVM has a number of "magic" global variables that contain data that affect
2752code generation or other IR semantics. These are documented here. All globals
Chris Lattner58f9bb22009-07-20 06:14:25 +0000[diff] [blame]2753of this sort should have a section specified as "<tt>llvm.metadata</tt>". This
2754section and all globals that start with "<tt>llvm.</tt>" are reserved for use
2755by LLVM.</p>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]2756
2757<!-- ======================================================================= -->
2758<div class="doc_subsection">
2759<a name="intg_used">The '<tt>llvm.used</tt>' Global Variable</a>
2760</div>
2761
2762<div class="doc_text">
2763
2764<p>The <tt>@llvm.used</tt> global is an array with i8* element type which has <a
2765href="#linkage_appending">appending linkage</a>. This array contains a list of
2766pointers to global variables and functions which may optionally have a pointer
2767cast formed of bitcast or getelementptr. For example, a legal use of it is:</p>
2768
2769<pre>
2770 @X = global i8 4
2771 @Y = global i32 123
2772
2773 @llvm.used = appending global [2 x i8*] [
2774 i8* @X,
2775 i8* bitcast (i32* @Y to i8*)
2776 ], section "llvm.metadata"
2777</pre>
2778
2779<p>If a global variable appears in the <tt>@llvm.used</tt> list, then the
2780compiler, assembler, and linker are required to treat the symbol as if there is
2781a reference to the global that it cannot see. For example, if a variable has
2782internal linkage and no references other than that from the <tt>@llvm.used</tt>
2783list, it cannot be deleted. This is commonly used to represent references from
2784inline asms and other things the compiler cannot "see", and corresponds to
2785"attribute((used))" in GNU C.</p>
2786
2787<p>On some targets, the code generator must emit a directive to the assembler or
2788object file to prevent the assembler and linker from molesting the symbol.</p>
2789
2790</div>
2791
2792<!-- ======================================================================= -->
2793<div class="doc_subsection">
Chris Lattner58f9bb22009-07-20 06:14:25 +0000[diff] [blame]2794<a name="intg_compiler_used">The '<tt>llvm.compiler.used</tt>' Global Variable</a>
2795</div>
2796
2797<div class="doc_text">
2798
2799<p>The <tt>@llvm.compiler.used</tt> directive is the same as the
2800<tt>@llvm.used</tt> directive, except that it only prevents the compiler from
2801touching the symbol. On targets that support it, this allows an intelligent
2802linker to optimize references to the symbol without being impeded as it would be
2803by <tt>@llvm.used</tt>.</p>
2804
2805<p>This is a rare construct that should only be used in rare circumstances, and
2806should not be exposed to source languages.</p>
2807
2808</div>
2809
2810<!-- ======================================================================= -->
2811<div class="doc_subsection">
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]2812<a name="intg_global_ctors">The '<tt>llvm.global_ctors</tt>' Global Variable</a>
2813</div>
2814
2815<div class="doc_text">
David Chisnalla9d4a6f2010-04-30 19:23:49 +0000[diff] [blame]2816<pre>
2817%0 = type { i32, void ()* }
David Chisnallb492b812010-04-30 19:27:35 +0000[diff] [blame]2818@llvm.global_ctors = appending global [1 x %0] [%0 { i32 65535, void ()* @ctor }]
David Chisnalla9d4a6f2010-04-30 19:23:49 +0000[diff] [blame]2819</pre>
2820<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.
2821</p>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]2822
2823</div>
2824
2825<!-- ======================================================================= -->
2826<div class="doc_subsection">
2827<a name="intg_global_dtors">The '<tt>llvm.global_dtors</tt>' Global Variable</a>
2828</div>
2829
2830<div class="doc_text">
David Chisnalla9d4a6f2010-04-30 19:23:49 +0000[diff] [blame]2831<pre>
2832%0 = type { i32, void ()* }
David Chisnallb492b812010-04-30 19:27:35 +0000[diff] [blame]2833@llvm.global_dtors = appending global [1 x %0] [%0 { i32 65535, void ()* @dtor }]
David Chisnalla9d4a6f2010-04-30 19:23:49 +0000[diff] [blame]2834</pre>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]2835
David Chisnalla9d4a6f2010-04-30 19:23:49 +0000[diff] [blame]2836<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.
2837</p>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]2838
2839</div>
2840
2841
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2842<!-- *********************************************************************** -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2843<div class="doc_section"> <a name="instref">Instruction Reference</a> </div>
2844<!-- *********************************************************************** -->
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2845
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2846<div class="doc_text">
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2847
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2848<p>The LLVM instruction set consists of several different classifications of
2849 instructions: <a href="#terminators">terminator
2850 instructions</a>, <a href="#binaryops">binary instructions</a>,
2851 <a href="#bitwiseops">bitwise binary instructions</a>,
2852 <a href="#memoryops">memory instructions</a>, and
2853 <a href="#otherops">other instructions</a>.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2854
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2855</div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2856
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2857<!-- ======================================================================= -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2858<div class="doc_subsection"> <a name="terminators">Terminator
2859Instructions</a> </div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2860
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2861<div class="doc_text">
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2862
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2863<p>As mentioned <a href="#functionstructure">previously</a>, every basic block
2864 in a program ends with a "Terminator" instruction, which indicates which
2865 block should be executed after the current block is finished. These
2866 terminator instructions typically yield a '<tt>void</tt>' value: they produce
2867 control flow, not values (the one exception being the
2868 '<a href="#i_invoke"><tt>invoke</tt></a>' instruction).</p>
2869
Duncan Sands626b0242010-04-15 20:35:54 +0000[diff] [blame]2870<p>There are seven different terminator instructions: the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2871 '<a href="#i_ret"><tt>ret</tt></a>' instruction, the
2872 '<a href="#i_br"><tt>br</tt></a>' instruction, the
2873 '<a href="#i_switch"><tt>switch</tt></a>' instruction, the
Bill Wendling33fef7e2009-11-02 00:25:26 +0000[diff] [blame]2874 '<a href="#i_indirectbr">'<tt>indirectbr</tt></a>' Instruction, the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2875 '<a href="#i_invoke"><tt>invoke</tt></a>' instruction, the
2876 '<a href="#i_unwind"><tt>unwind</tt></a>' instruction, and the
2877 '<a href="#i_unreachable"><tt>unreachable</tt></a>' instruction.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2878
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2879</div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2880
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2881<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2882<div class="doc_subsubsection"> <a name="i_ret">'<tt>ret</tt>'
2883Instruction</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2884
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2885<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2886
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2887<h5>Syntax:</h5>
Dan Gohmancc3132e2008-10-04 19:00:07 +0000[diff] [blame]2888<pre>
2889 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]2890 ret void <i>; Return from void function</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2891</pre>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]2892
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2893<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2894<p>The '<tt>ret</tt>' instruction is used to return control flow (and optionally
2895 a value) from a function back to the caller.</p>
2896
2897<p>There are two forms of the '<tt>ret</tt>' instruction: one that returns a
2898 value and then causes control flow, and one that just causes control flow to
2899 occur.</p>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]2900
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2901<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2902<p>The '<tt>ret</tt>' instruction optionally accepts a single argument, the
2903 return value. The type of the return value must be a
2904 '<a href="#t_firstclass">first class</a>' type.</p>
Dan Gohmancc3132e2008-10-04 19:00:07 +0000[diff] [blame]2905
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2906<p>A function is not <a href="#wellformed">well formed</a> if it it has a
2907 non-void return type and contains a '<tt>ret</tt>' instruction with no return
2908 value or a return value with a type that does not match its type, or if it
2909 has a void return type and contains a '<tt>ret</tt>' instruction with a
2910 return value.</p>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]2911
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2912<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2913<p>When the '<tt>ret</tt>' instruction is executed, control flow returns back to
2914 the calling function's context. If the caller is a
2915 "<a href="#i_call"><tt>call</tt></a>" instruction, execution continues at the
2916 instruction after the call. If the caller was an
2917 "<a href="#i_invoke"><tt>invoke</tt></a>" instruction, execution continues at
2918 the beginning of the "normal" destination block. If the instruction returns
2919 a value, that value shall set the call or invoke instruction's return
2920 value.</p>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]2921
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2922<h5>Example:</h5>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]2923<pre>
2924 ret i32 5 <i>; Return an integer value of 5</i>
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]2925 ret void <i>; Return from a void function</i>
Bill Wendling050ee8f2009-02-28 22:12:54 +0000[diff] [blame]2926 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]2927</pre>
Dan Gohman3065b612009-01-12 23:12:39 +0000[diff] [blame]2928
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2929</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2930<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2931<div class="doc_subsubsection"> <a name="i_br">'<tt>br</tt>' Instruction</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2932
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2933<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2934
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2935<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2936<pre>
2937 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]2938</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2939
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2940<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2941<p>The '<tt>br</tt>' instruction is used to cause control flow to transfer to a
2942 different basic block in the current function. There are two forms of this
2943 instruction, corresponding to a conditional branch and an unconditional
2944 branch.</p>
2945
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2946<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2947<p>The conditional branch form of the '<tt>br</tt>' instruction takes a single
2948 '<tt>i1</tt>' value and two '<tt>label</tt>' values. The unconditional form
2949 of the '<tt>br</tt>' instruction takes a single '<tt>label</tt>' value as a
2950 target.</p>
2951
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2952<h5>Semantics:</h5>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]2953<p>Upon execution of a conditional '<tt>br</tt>' instruction, the '<tt>i1</tt>'
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2954 argument is evaluated. If the value is <tt>true</tt>, control flows to the
2955 '<tt>iftrue</tt>' <tt>label</tt> argument. If "cond" is <tt>false</tt>,
2956 control flows to the '<tt>iffalse</tt>' <tt>label</tt> argument.</p>
2957
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2958<h5>Example:</h5>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]2959<pre>
2960Test:
2961 %cond = <a href="#i_icmp">icmp</a> eq i32 %a, %b
2962 br i1 %cond, label %IfEqual, label %IfUnequal
2963IfEqual:
2964 <a href="#i_ret">ret</a> i32 1
2965IfUnequal:
2966 <a href="#i_ret">ret</a> i32 0
2967</pre>
2968
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2969</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2970
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2971<!-- _______________________________________________________________________ -->
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2972<div class="doc_subsubsection">
2973 <a name="i_switch">'<tt>switch</tt>' Instruction</a>
2974</div>
2975
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2976<div class="doc_text">
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2977
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2978<h5>Syntax:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2979<pre>
2980 switch &lt;intty&gt; &lt;value&gt;, label &lt;defaultdest&gt; [ &lt;intty&gt; &lt;val&gt;, label &lt;dest&gt; ... ]
2981</pre>
2982
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2983<h5>Overview:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2984<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]2985 several different places. It is a generalization of the '<tt>br</tt>'
2986 instruction, allowing a branch to occur to one of many possible
2987 destinations.</p>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2988
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2989<h5>Arguments:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2990<p>The '<tt>switch</tt>' instruction uses three parameters: an integer
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2991 comparison value '<tt>value</tt>', a default '<tt>label</tt>' destination,
2992 and an array of pairs of comparison value constants and '<tt>label</tt>'s.
2993 The table is not allowed to contain duplicate constant entries.</p>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2994
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2995<h5>Semantics:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2996<p>The <tt>switch</tt> instruction specifies a table of values and
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2997 destinations. When the '<tt>switch</tt>' instruction is executed, this table
2998 is searched for the given value. If the value is found, control flow is
Benjamin Kramer0f420382009-10-12 14:46:08 +0000[diff] [blame]2999 transferred to the corresponding destination; otherwise, control flow is
3000 transferred to the default destination.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3001
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]3002<h5>Implementation:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]3003<p>Depending on properties of the target machine and the particular
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3004 <tt>switch</tt> instruction, this instruction may be code generated in
3005 different ways. For example, it could be generated as a series of chained
3006 conditional branches or with a lookup table.</p>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]3007
3008<h5>Example:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]3009<pre>
3010 <i>; Emulate a conditional br instruction</i>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]3011 %Val = <a href="#i_zext">zext</a> i1 %value to i32
Dan Gohman623806e2009-01-04 23:44:43 +0000[diff] [blame]3012 switch i32 %Val, label %truedest [ i32 0, label %falsedest ]
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]3013
3014 <i>; Emulate an unconditional br instruction</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3015 switch i32 0, label %dest [ ]
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]3016
3017 <i>; Implement a jump table:</i>
Dan Gohman623806e2009-01-04 23:44:43 +0000[diff] [blame]3018 switch i32 %val, label %otherwise [ i32 0, label %onzero
3019 i32 1, label %onone
3020 i32 2, label %ontwo ]
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3021</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3022
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3023</div>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3024
Chris Lattner3ed871f2009-10-27 19:13:16 +0000[diff] [blame]3025
3026<!-- _______________________________________________________________________ -->
3027<div class="doc_subsubsection">
Chris Lattnerd04cb6d2009-10-28 00:19:10 +0000[diff] [blame]3028 <a name="i_indirectbr">'<tt>indirectbr</tt>' Instruction</a>
Chris Lattner3ed871f2009-10-27 19:13:16 +0000[diff] [blame]3029</div>
3030
3031<div class="doc_text">
3032
3033<h5>Syntax:</h5>
3034<pre>
Chris Lattnerd04cb6d2009-10-28 00:19:10 +0000[diff] [blame]3035 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]3036</pre>
3037
3038<h5>Overview:</h5>
3039
Chris Lattnerd04cb6d2009-10-28 00:19:10 +0000[diff] [blame]3040<p>The '<tt>indirectbr</tt>' instruction implements an indirect branch to a label
Chris Lattner3ed871f2009-10-27 19:13:16 +0000[diff] [blame]3041 within the current function, whose address is specified by
Chris Lattnere4801f72009-10-27 21:01:34 +0000[diff] [blame]3042 "<tt>address</tt>". Address must be derived from a <a
3043 href="#blockaddress">blockaddress</a> constant.</p>
Chris Lattner3ed871f2009-10-27 19:13:16 +0000[diff] [blame]3044
3045<h5>Arguments:</h5>
3046
3047<p>The '<tt>address</tt>' argument is the address of the label to jump to. The
3048 rest of the arguments indicate the full set of possible destinations that the
3049 address may point to. Blocks are allowed to occur multiple times in the
3050 destination list, though this isn't particularly useful.</p>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3051
Chris Lattner3ed871f2009-10-27 19:13:16 +0000[diff] [blame]3052<p>This destination list is required so that dataflow analysis has an accurate
3053 understanding of the CFG.</p>
3054
3055<h5>Semantics:</h5>
3056
3057<p>Control transfers to the block specified in the address argument. All
3058 possible destination blocks must be listed in the label list, otherwise this
3059 instruction has undefined behavior. This implies that jumps to labels
3060 defined in other functions have undefined behavior as well.</p>
3061
3062<h5>Implementation:</h5>
3063
3064<p>This is typically implemented with a jump through a register.</p>
3065
3066<h5>Example:</h5>
3067<pre>
Chris Lattnerd04cb6d2009-10-28 00:19:10 +0000[diff] [blame]3068 indirectbr i8* %Addr, [ label %bb1, label %bb2, label %bb3 ]
Chris Lattner3ed871f2009-10-27 19:13:16 +0000[diff] [blame]3069</pre>
3070
3071</div>
3072
3073
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3074<!-- _______________________________________________________________________ -->
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3075<div class="doc_subsubsection">
3076 <a name="i_invoke">'<tt>invoke</tt>' Instruction</a>
3077</div>
3078
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3079<div class="doc_text">
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3080
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3081<h5>Syntax:</h5>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3082<pre>
Devang Patel02256232008-10-07 17:48:33 +0000[diff] [blame]3083 &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]3084 to label &lt;normal label&gt; unwind label &lt;exception label&gt;
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3085</pre>
3086
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]3087<h5>Overview:</h5>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3088<p>The '<tt>invoke</tt>' instruction causes control to transfer to a specified
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3089 function, with the possibility of control flow transfer to either the
3090 '<tt>normal</tt>' label or the '<tt>exception</tt>' label. If the callee
3091 function returns with the "<tt><a href="#i_ret">ret</a></tt>" instruction,
3092 control flow will return to the "normal" label. If the callee (or any
3093 indirect callees) returns with the "<a href="#i_unwind"><tt>unwind</tt></a>"
3094 instruction, control is interrupted and continued at the dynamically nearest
3095 "exception" label.</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3096
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3097<h5>Arguments:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3098<p>This instruction requires several arguments:</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3099
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3100<ol>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3101 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
3102 convention</a> the call should use. If none is specified, the call
3103 defaults to using C calling conventions.</li>
Devang Patel7e9b05e2008-10-06 18:50:38 +0000[diff] [blame]3104
3105 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3106 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
3107 '<tt>inreg</tt>' attributes are valid here.</li>
Devang Patel7e9b05e2008-10-06 18:50:38 +0000[diff] [blame]3108
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3109 <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]3110 function value being invoked. In most cases, this is a direct function
3111 invocation, but indirect <tt>invoke</tt>s are just as possible, branching
3112 off an arbitrary pointer to function value.</li>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3113
3114 <li>'<tt>function ptr val</tt>': An LLVM value containing a pointer to a
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3115 function to be invoked. </li>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3116
3117 <li>'<tt>function args</tt>': argument list whose types match the function
Chris Lattner47f2a832010-03-02 06:36:51 +0000[diff] [blame]3118 signature argument types and parameter attributes. All arguments must be
3119 of <a href="#t_firstclass">first class</a> type. If the function
3120 signature indicates the function accepts a variable number of arguments,
3121 the extra arguments can be specified.</li>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3122
3123 <li>'<tt>normal label</tt>': the label reached when the called function
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3124 executes a '<tt><a href="#i_ret">ret</a></tt>' instruction. </li>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3125
3126 <li>'<tt>exception label</tt>': the label reached when a callee returns with
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3127 the <a href="#i_unwind"><tt>unwind</tt></a> instruction. </li>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3128
Devang Patel02256232008-10-07 17:48:33 +0000[diff] [blame]3129 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3130 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
3131 '<tt>readnone</tt>' attributes are valid here.</li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3132</ol>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3133
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3134<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3135<p>This instruction is designed to operate as a standard
3136 '<tt><a href="#i_call">call</a></tt>' instruction in most regards. The
3137 primary difference is that it establishes an association with a label, which
3138 is used by the runtime library to unwind the stack.</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3139
3140<p>This instruction is used in languages with destructors to ensure that proper
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3141 cleanup is performed in the case of either a <tt>longjmp</tt> or a thrown
3142 exception. Additionally, this is important for implementation of
3143 '<tt>catch</tt>' clauses in high-level languages that support them.</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3144
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3145<p>For the purposes of the SSA form, the definition of the value returned by the
3146 '<tt>invoke</tt>' instruction is deemed to occur on the edge from the current
3147 block to the "normal" label. If the callee unwinds then no return value is
3148 available.</p>
Dan Gohman9069d892009-05-22 21:47:08 +0000[diff] [blame]3149
Chris Lattner97257f82010-01-15 18:08:37 +0000[diff] [blame]3150<p>Note that the code generator does not yet completely support unwind, and
3151that the invoke/unwind semantics are likely to change in future versions.</p>
3152
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3153<h5>Example:</h5>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3154<pre>
Nick Lewycky084ab472008-03-16 07:18:12 +0000[diff] [blame]3155 %retval = invoke i32 @Test(i32 15) to label %Continue
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]3156 unwind label %TestCleanup <i>; {i32}:retval set</i>
Nick Lewycky084ab472008-03-16 07:18:12 +0000[diff] [blame]3157 %retval = invoke <a href="#callingconv">coldcc</a> i32 %Testfnptr(i32 15) to label %Continue
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]3158 unwind label %TestCleanup <i>; {i32}:retval set</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3159</pre>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3160
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3161</div>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3162
Chris Lattner5ed60612003-09-03 00:41:47 +0000[diff] [blame]3163<!-- _______________________________________________________________________ -->
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3164
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3165<div class="doc_subsubsection"> <a name="i_unwind">'<tt>unwind</tt>'
3166Instruction</a> </div>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3167
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3168<div class="doc_text">
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3169
Chris Lattner5ed60612003-09-03 00:41:47 +0000[diff] [blame]3170<h5>Syntax:</h5>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3171<pre>
3172 unwind
3173</pre>
3174
Chris Lattner5ed60612003-09-03 00:41:47 +0000[diff] [blame]3175<h5>Overview:</h5>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3176<p>The '<tt>unwind</tt>' instruction unwinds the stack, continuing control flow
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3177 at the first callee in the dynamic call stack which used
3178 an <a href="#i_invoke"><tt>invoke</tt></a> instruction to perform the call.
3179 This is primarily used to implement exception handling.</p>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3180
Chris Lattner5ed60612003-09-03 00:41:47 +0000[diff] [blame]3181<h5>Semantics:</h5>
Chris Lattnerfe8519c2008-04-19 21:01:16 +0000[diff] [blame]3182<p>The '<tt>unwind</tt>' instruction causes execution of the current function to
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3183 immediately halt. The dynamic call stack is then searched for the
3184 first <a href="#i_invoke"><tt>invoke</tt></a> instruction on the call stack.
3185 Once found, execution continues at the "exceptional" destination block
3186 specified by the <tt>invoke</tt> instruction. If there is no <tt>invoke</tt>
3187 instruction in the dynamic call chain, undefined behavior results.</p>
3188
Chris Lattner97257f82010-01-15 18:08:37 +0000[diff] [blame]3189<p>Note that the code generator does not yet completely support unwind, and
3190that the invoke/unwind semantics are likely to change in future versions.</p>
3191
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3192</div>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3193
3194<!-- _______________________________________________________________________ -->
3195
3196<div class="doc_subsubsection"> <a name="i_unreachable">'<tt>unreachable</tt>'
3197Instruction</a> </div>
3198
3199<div class="doc_text">
3200
3201<h5>Syntax:</h5>
3202<pre>
3203 unreachable
3204</pre>
3205
3206<h5>Overview:</h5>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3207<p>The '<tt>unreachable</tt>' instruction has no defined semantics. This
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3208 instruction is used to inform the optimizer that a particular portion of the
3209 code is not reachable. This can be used to indicate that the code after a
3210 no-return function cannot be reached, and other facts.</p>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3211
3212<h5>Semantics:</h5>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3213<p>The '<tt>unreachable</tt>' instruction has no defined semantics.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3214
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3215</div>
3216
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3217<!-- ======================================================================= -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3218<div class="doc_subsection"> <a name="binaryops">Binary Operations</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3219
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3220<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3221
3222<p>Binary operators are used to do most of the computation in a program. They
3223 require two operands of the same type, execute an operation on them, and
3224 produce a single value. The operands might represent multiple data, as is
3225 the case with the <a href="#t_vector">vector</a> data type. The result value
3226 has the same type as its operands.</p>
3227
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3228<p>There are several different binary operators:</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3229
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3230</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3231
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3232<!-- _______________________________________________________________________ -->
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3233<div class="doc_subsubsection">
3234 <a name="i_add">'<tt>add</tt>' Instruction</a>
3235</div>
3236
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3237<div class="doc_text">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3238
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3239<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3240<pre>
Dan Gohmanb07de442009-07-20 22:41:19 +0000[diff] [blame]3241 &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]3242 &lt;result&gt; = add nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3243 &lt;result&gt; = add nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3244 &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]3245</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3246
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3247<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3248<p>The '<tt>add</tt>' instruction returns the sum of its two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3249
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3250<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3251<p>The two arguments to the '<tt>add</tt>' instruction must
3252 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3253 integer values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3254
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3255<h5>Semantics:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3256<p>The value produced is the integer sum of the two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3257
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3258<p>If the sum has unsigned overflow, the result returned is the mathematical
3259 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]3260
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3261<p>Because LLVM integers use a two's complement representation, this instruction
3262 is appropriate for both signed and unsigned integers.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3263
Dan Gohman902dfff2009-07-22 22:44:56 +0000[diff] [blame]3264<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3265 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3266 <tt>nsw</tt> keywords are present, the result value of the <tt>add</tt>
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]3267 is a <a href="#trapvalues">trap value</a> if unsigned and/or signed overflow,
3268 respectively, occurs.</p>
Dan Gohmanb07de442009-07-20 22:41:19 +0000[diff] [blame]3269
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3270<h5>Example:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3271<pre>
3272 &lt;result&gt; = add i32 4, %var <i>; yields {i32}:result = 4 + %var</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3273</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3274
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3275</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3276
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3277<!-- _______________________________________________________________________ -->
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3278<div class="doc_subsubsection">
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3279 <a name="i_fadd">'<tt>fadd</tt>' Instruction</a>
3280</div>
3281
3282<div class="doc_text">
3283
3284<h5>Syntax:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3285<pre>
3286 &lt;result&gt; = fadd &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3287</pre>
3288
3289<h5>Overview:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3290<p>The '<tt>fadd</tt>' instruction returns the sum of its two operands.</p>
3291
3292<h5>Arguments:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3293<p>The two arguments to the '<tt>fadd</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3294 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3295 floating point values. Both arguments must have identical types.</p>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3296
3297<h5>Semantics:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3298<p>The value produced is the floating point sum of the two operands.</p>
3299
3300<h5>Example:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3301<pre>
3302 &lt;result&gt; = fadd float 4.0, %var <i>; yields {float}:result = 4.0 + %var</i>
3303</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3304
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3305</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3306
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3307<!-- _______________________________________________________________________ -->
3308<div class="doc_subsubsection">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3309 <a name="i_sub">'<tt>sub</tt>' Instruction</a>
3310</div>
3311
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3312<div class="doc_text">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3313
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3314<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3315<pre>
Dan Gohman902dfff2009-07-22 22:44:56 +0000[diff] [blame]3316 &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]3317 &lt;result&gt; = sub nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3318 &lt;result&gt; = sub nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3319 &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]3320</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3321
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3322<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3323<p>The '<tt>sub</tt>' instruction returns the difference of its two
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3324 operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3325
3326<p>Note that the '<tt>sub</tt>' instruction is used to represent the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3327 '<tt>neg</tt>' instruction present in most other intermediate
3328 representations.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3329
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3330<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3331<p>The two arguments to the '<tt>sub</tt>' instruction must
3332 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3333 integer values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3334
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3335<h5>Semantics:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3336<p>The value produced is the integer difference of the two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3337
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3338<p>If the difference has unsigned overflow, the result returned is the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3339 mathematical result modulo 2<sup>n</sup>, where n is the bit width of the
3340 result.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3341
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3342<p>Because LLVM integers use a two's complement representation, this instruction
3343 is appropriate for both signed and unsigned integers.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3344
Dan Gohman902dfff2009-07-22 22:44:56 +0000[diff] [blame]3345<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3346 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3347 <tt>nsw</tt> keywords are present, the result value of the <tt>sub</tt>
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]3348 is a <a href="#trapvalues">trap value</a> if unsigned and/or signed overflow,
3349 respectively, occurs.</p>
Dan Gohmanb07de442009-07-20 22:41:19 +0000[diff] [blame]3350
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3351<h5>Example:</h5>
Bill Wendling2d8b9a82007-05-29 09:42:13 +0000[diff] [blame]3352<pre>
3353 &lt;result&gt; = sub i32 4, %var <i>; yields {i32}:result = 4 - %var</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3354 &lt;result&gt; = sub i32 0, %val <i>; yields {i32}:result = -%var</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3355</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3356
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3357</div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3358
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3359<!-- _______________________________________________________________________ -->
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3360<div class="doc_subsubsection">
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3361 <a name="i_fsub">'<tt>fsub</tt>' Instruction</a>
3362</div>
3363
3364<div class="doc_text">
3365
3366<h5>Syntax:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3367<pre>
3368 &lt;result&gt; = fsub &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3369</pre>
3370
3371<h5>Overview:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3372<p>The '<tt>fsub</tt>' instruction returns the difference of its two
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3373 operands.</p>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3374
3375<p>Note that the '<tt>fsub</tt>' instruction is used to represent the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3376 '<tt>fneg</tt>' instruction present in most other intermediate
3377 representations.</p>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3378
3379<h5>Arguments:</h5>
Bill Wendling972b7202009-07-20 02:32:41 +0000[diff] [blame]3380<p>The two arguments to the '<tt>fsub</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3381 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3382 floating point values. Both arguments must have identical types.</p>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3383
3384<h5>Semantics:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3385<p>The value produced is the floating point difference of the two operands.</p>
3386
3387<h5>Example:</h5>
3388<pre>
3389 &lt;result&gt; = fsub float 4.0, %var <i>; yields {float}:result = 4.0 - %var</i>
3390 &lt;result&gt; = fsub float -0.0, %val <i>; yields {float}:result = -%var</i>
3391</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3392
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3393</div>
3394
3395<!-- _______________________________________________________________________ -->
3396<div class="doc_subsubsection">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3397 <a name="i_mul">'<tt>mul</tt>' Instruction</a>
3398</div>
3399
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3400<div class="doc_text">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3401
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3402<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3403<pre>
Dan Gohman902dfff2009-07-22 22:44:56 +0000[diff] [blame]3404 &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]3405 &lt;result&gt; = mul nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3406 &lt;result&gt; = mul nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3407 &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]3408</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3409
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3410<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3411<p>The '<tt>mul</tt>' instruction returns the product of its two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3412
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3413<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3414<p>The two arguments to the '<tt>mul</tt>' instruction must
3415 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3416 integer values. Both arguments must have identical types.</p>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3417
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3418<h5>Semantics:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3419<p>The value produced is the integer product of the two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3420
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3421<p>If the result of the multiplication has unsigned overflow, the result
3422 returned is the mathematical result modulo 2<sup>n</sup>, where n is the bit
3423 width of the result.</p>
3424
3425<p>Because LLVM integers use a two's complement representation, and the result
3426 is the same width as the operands, this instruction returns the correct
3427 result for both signed and unsigned integers. If a full product
3428 (e.g. <tt>i32</tt>x<tt>i32</tt>-><tt>i64</tt>) is needed, the operands should
3429 be sign-extended or zero-extended as appropriate to the width of the full
3430 product.</p>
3431
Dan Gohman902dfff2009-07-22 22:44:56 +0000[diff] [blame]3432<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3433 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3434 <tt>nsw</tt> keywords are present, the result value of the <tt>mul</tt>
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]3435 is a <a href="#trapvalues">trap value</a> if unsigned and/or signed overflow,
3436 respectively, occurs.</p>
Dan Gohmanb07de442009-07-20 22:41:19 +0000[diff] [blame]3437
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3438<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3439<pre>
3440 &lt;result&gt; = mul i32 4, %var <i>; yields {i32}:result = 4 * %var</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3441</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3442
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3443</div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3444
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3445<!-- _______________________________________________________________________ -->
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3446<div class="doc_subsubsection">
3447 <a name="i_fmul">'<tt>fmul</tt>' Instruction</a>
3448</div>
3449
3450<div class="doc_text">
3451
3452<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3453<pre>
3454 &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]3455</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3456
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3457<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3458<p>The '<tt>fmul</tt>' instruction returns the product of its two operands.</p>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3459
3460<h5>Arguments:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3461<p>The two arguments to the '<tt>fmul</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3462 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3463 floating point values. Both arguments must have identical types.</p>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3464
3465<h5>Semantics:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3466<p>The value produced is the floating point product of the two operands.</p>
3467
3468<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3469<pre>
3470 &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]3471</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3472
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3473</div>
3474
3475<!-- _______________________________________________________________________ -->
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3476<div class="doc_subsubsection"> <a name="i_udiv">'<tt>udiv</tt>' Instruction
3477</a></div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3478
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3479<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3480
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3481<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3482<pre>
3483 &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]3484</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3485
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3486<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3487<p>The '<tt>udiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3488
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3489<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3490<p>The two arguments to the '<tt>udiv</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3491 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3492 values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3493
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3494<h5>Semantics:</h5>
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3495<p>The value produced is the unsigned integer quotient of the two operands.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3496
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3497<p>Note that unsigned integer division and signed integer division are distinct
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3498 operations; for signed integer division, use '<tt>sdiv</tt>'.</p>
3499
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3500<p>Division by zero leads to undefined behavior.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3501
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3502<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3503<pre>
3504 &lt;result&gt; = udiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3505</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3506
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3507</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3508
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3509<!-- _______________________________________________________________________ -->
3510<div class="doc_subsubsection"> <a name="i_sdiv">'<tt>sdiv</tt>' Instruction
3511</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3512
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3513<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3514
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3515<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3516<pre>
Dan Gohmanb07de442009-07-20 22:41:19 +0000[diff] [blame]3517 &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]3518 &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]3519</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3520
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3521<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3522<p>The '<tt>sdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3523
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3524<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3525<p>The two arguments to the '<tt>sdiv</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3526 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3527 values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3528
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3529<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3530<p>The value produced is the signed integer quotient of the two operands rounded
3531 towards zero.</p>
3532
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3533<p>Note that signed integer division and unsigned integer division are distinct
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3534 operations; for unsigned integer division, use '<tt>udiv</tt>'.</p>
3535
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3536<p>Division by zero leads to undefined behavior. Overflow also leads to
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3537 undefined behavior; this is a rare case, but can occur, for example, by doing
3538 a 32-bit division of -2147483648 by -1.</p>
3539
Dan Gohman71dfd782009-07-22 00:04:19 +0000[diff] [blame]3540<p>If the <tt>exact</tt> keyword is present, the result value of the
Dan Gohman57255802010-04-23 15:23:32 +0000[diff] [blame]3541 <tt>sdiv</tt> is a <a href="#trapvalues">trap value</a> if the result would
3542 be rounded or if overflow would occur.</p>
Dan Gohmanb07de442009-07-20 22:41:19 +0000[diff] [blame]3543
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3544<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3545<pre>
3546 &lt;result&gt; = sdiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3547</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3548
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3549</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3550
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3551<!-- _______________________________________________________________________ -->
3552<div class="doc_subsubsection"> <a name="i_fdiv">'<tt>fdiv</tt>'
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3553Instruction</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3554
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3555<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3556
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3557<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3558<pre>
Gabor Greif0f75ad02008-08-07 21:46:00 +0000[diff] [blame]3559 &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]3560</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3561
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3562<h5>Overview:</h5>
3563<p>The '<tt>fdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3564
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3565<h5>Arguments:</h5>
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]3566<p>The two arguments to the '<tt>fdiv</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3567 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3568 floating point values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3569
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3570<h5>Semantics:</h5>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3571<p>The value produced is the floating point quotient of the two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3572
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3573<h5>Example:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3574<pre>
3575 &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]3576</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3577
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3578</div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3579
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3580<!-- _______________________________________________________________________ -->
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3581<div class="doc_subsubsection"> <a name="i_urem">'<tt>urem</tt>' Instruction</a>
3582</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3583
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3584<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3585
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3586<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3587<pre>
3588 &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]3589</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3590
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3591<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3592<p>The '<tt>urem</tt>' instruction returns the remainder from the unsigned
3593 division of its two arguments.</p>
3594
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3595<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3596<p>The two arguments to the '<tt>urem</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3597 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3598 values. Both arguments must have identical types.</p>
3599
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3600<h5>Semantics:</h5>
3601<p>This instruction returns the unsigned integer <i>remainder</i> of a division.
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3602 This instruction always performs an unsigned division to get the
3603 remainder.</p>
3604
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3605<p>Note that unsigned integer remainder and signed integer remainder are
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3606 distinct operations; for signed integer remainder, use '<tt>srem</tt>'.</p>
3607
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3608<p>Taking the remainder of a division by zero leads to undefined behavior.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3609
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3610<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3611<pre>
3612 &lt;result&gt; = urem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3613</pre>
3614
3615</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3616
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3617<!-- _______________________________________________________________________ -->
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3618<div class="doc_subsubsection">
3619 <a name="i_srem">'<tt>srem</tt>' Instruction</a>
3620</div>
3621
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3622<div class="doc_text">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3623
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3624<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3625<pre>
Gabor Greif0f75ad02008-08-07 21:46:00 +0000[diff] [blame]3626 &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]3627</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3628
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3629<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3630<p>The '<tt>srem</tt>' instruction returns the remainder from the signed
3631 division of its two operands. This instruction can also take
3632 <a href="#t_vector">vector</a> versions of the values in which case the
3633 elements must be integers.</p>
Chris Lattnerb8f816e2008-01-04 04:33:49 +0000[diff] [blame]3634
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3635<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3636<p>The two arguments to the '<tt>srem</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3637 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3638 values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3639
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3640<h5>Semantics:</h5>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3641<p>This instruction returns the <i>remainder</i> of a division (where the result
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3642 has the same sign as the dividend, <tt>op1</tt>), not the <i>modulo</i>
3643 operator (where the result has the same sign as the divisor, <tt>op2</tt>) of
3644 a value. For more information about the difference,
3645 see <a href="http://mathforum.org/dr.math/problems/anne.4.28.99.html">The
3646 Math Forum</a>. For a table of how this is implemented in various languages,
3647 please see <a href="http://en.wikipedia.org/wiki/Modulo_operation">
3648 Wikipedia: modulo operation</a>.</p>
3649
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3650<p>Note that signed integer remainder and unsigned integer remainder are
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3651 distinct operations; for unsigned integer remainder, use '<tt>urem</tt>'.</p>
3652
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3653<p>Taking the remainder of a division by zero leads to undefined behavior.
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3654 Overflow also leads to undefined behavior; this is a rare case, but can
3655 occur, for example, by taking the remainder of a 32-bit division of
3656 -2147483648 by -1. (The remainder doesn't actually overflow, but this rule
3657 lets srem be implemented using instructions that return both the result of
3658 the division and the remainder.)</p>
3659
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3660<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3661<pre>
3662 &lt;result&gt; = srem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3663</pre>
3664
3665</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3666
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3667<!-- _______________________________________________________________________ -->
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3668<div class="doc_subsubsection">
3669 <a name="i_frem">'<tt>frem</tt>' Instruction</a> </div>
3670
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3671<div class="doc_text">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3672
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3673<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3674<pre>
3675 &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]3676</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3677
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3678<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3679<p>The '<tt>frem</tt>' instruction returns the remainder from the division of
3680 its two operands.</p>
3681
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3682<h5>Arguments:</h5>
3683<p>The two arguments to the '<tt>frem</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3684 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3685 floating point values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3686
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3687<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3688<p>This instruction returns the <i>remainder</i> of a division. The remainder
3689 has the same sign as the dividend.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3690
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3691<h5>Example:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3692<pre>
3693 &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]3694</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3695
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3696</div>
Robert Bocchino820bc75b2006-02-17 21:18:08 +0000[diff] [blame]3697
Reid Spencer2ab01932007-02-02 13:57:07 +0000[diff] [blame]3698<!-- ======================================================================= -->
3699<div class="doc_subsection"> <a name="bitwiseops">Bitwise Binary
3700Operations</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3701
Reid Spencer2ab01932007-02-02 13:57:07 +0000[diff] [blame]3702<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3703
3704<p>Bitwise binary operators are used to do various forms of bit-twiddling in a
3705 program. They are generally very efficient instructions and can commonly be
3706 strength reduced from other instructions. They require two operands of the
3707 same type, execute an operation on them, and produce a single value. The
3708 resulting value is the same type as its operands.</p>
3709
Reid Spencer2ab01932007-02-02 13:57:07 +0000[diff] [blame]3710</div>
3711
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3712<!-- _______________________________________________________________________ -->
3713<div class="doc_subsubsection"> <a name="i_shl">'<tt>shl</tt>'
3714Instruction</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3715
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3716<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3717
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3718<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3719<pre>
3720 &lt;result&gt; = 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]3721</pre>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]3722
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3723<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3724<p>The '<tt>shl</tt>' instruction returns the first operand shifted to the left
3725 a specified number of bits.</p>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]3726
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3727<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3728<p>Both arguments to the '<tt>shl</tt>' instruction must be the
3729 same <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3730 integer type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3731
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3732<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3733<p>The value produced is <tt>op1</tt> * 2<sup><tt>op2</tt></sup> mod
3734 2<sup>n</sup>, where <tt>n</tt> is the width of the result. If <tt>op2</tt>
3735 is (statically or dynamically) negative or equal to or larger than the number
3736 of bits in <tt>op1</tt>, the result is undefined. If the arguments are
3737 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
3738 shift amount in <tt>op2</tt>.</p>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]3739
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3740<h5>Example:</h5>
3741<pre>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3742 &lt;result&gt; = shl i32 4, %var <i>; yields {i32}: 4 &lt;&lt; %var</i>
3743 &lt;result&gt; = shl i32 4, 2 <i>; yields {i32}: 16</i>
3744 &lt;result&gt; = shl i32 1, 10 <i>; yields {i32}: 1024</i>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]3745 &lt;result&gt; = shl i32 1, 32 <i>; undefined</i>
Mon P Wang4dd832d2008-12-09 05:46:39 +0000[diff] [blame]3746 &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]3747</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3748
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3749</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3750
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3751<!-- _______________________________________________________________________ -->
3752<div class="doc_subsubsection"> <a name="i_lshr">'<tt>lshr</tt>'
3753Instruction</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3754
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3755<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3756
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3757<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3758<pre>
3759 &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]3760</pre>
3761
3762<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3763<p>The '<tt>lshr</tt>' instruction (logical shift right) returns the first
3764 operand shifted to the right a specified number of bits with zero fill.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3765
3766<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3767<p>Both arguments to the '<tt>lshr</tt>' instruction must be the same
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3768 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3769 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3770
3771<h5>Semantics:</h5>
3772<p>This instruction always performs a logical shift right operation. The most
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3773 significant bits of the result will be filled with zero bits after the shift.
3774 If <tt>op2</tt> is (statically or dynamically) equal to or larger than the
3775 number of bits in <tt>op1</tt>, the result is undefined. If the arguments are
3776 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
3777 shift amount in <tt>op2</tt>.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3778
3779<h5>Example:</h5>
3780<pre>
3781 &lt;result&gt; = lshr i32 4, 1 <i>; yields {i32}:result = 2</i>
3782 &lt;result&gt; = lshr i32 4, 2 <i>; yields {i32}:result = 1</i>
3783 &lt;result&gt; = lshr i8 4, 3 <i>; yields {i8}:result = 0</i>
3784 &lt;result&gt; = lshr i8 -2, 1 <i>; yields {i8}:result = 0x7FFFFFFF </i>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]3785 &lt;result&gt; = lshr i32 1, 32 <i>; undefined</i>
Mon P Wang4dd832d2008-12-09 05:46:39 +0000[diff] [blame]3786 &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]3787</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3788
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3789</div>
3790
Reid Spencer2ab01932007-02-02 13:57:07 +0000[diff] [blame]3791<!-- _______________________________________________________________________ -->
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3792<div class="doc_subsubsection"> <a name="i_ashr">'<tt>ashr</tt>'
3793Instruction</a> </div>
3794<div class="doc_text">
3795
3796<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3797<pre>
3798 &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]3799</pre>
3800
3801<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3802<p>The '<tt>ashr</tt>' instruction (arithmetic shift right) returns the first
3803 operand shifted to the right a specified number of bits with sign
3804 extension.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3805
3806<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3807<p>Both arguments to the '<tt>ashr</tt>' instruction must be the same
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3808 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3809 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3810
3811<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3812<p>This instruction always performs an arithmetic shift right operation, The
3813 most significant bits of the result will be filled with the sign bit
3814 of <tt>op1</tt>. If <tt>op2</tt> is (statically or dynamically) equal to or
3815 larger than the number of bits in <tt>op1</tt>, the result is undefined. If
3816 the arguments are vectors, each vector element of <tt>op1</tt> is shifted by
3817 the corresponding shift amount in <tt>op2</tt>.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3818
3819<h5>Example:</h5>
3820<pre>
3821 &lt;result&gt; = ashr i32 4, 1 <i>; yields {i32}:result = 2</i>
3822 &lt;result&gt; = ashr i32 4, 2 <i>; yields {i32}:result = 1</i>
3823 &lt;result&gt; = ashr i8 4, 3 <i>; yields {i8}:result = 0</i>
3824 &lt;result&gt; = ashr i8 -2, 1 <i>; yields {i8}:result = -1</i>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]3825 &lt;result&gt; = ashr i32 1, 32 <i>; undefined</i>
Mon P Wang4dd832d2008-12-09 05:46:39 +0000[diff] [blame]3826 &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]3827</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3828
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3829</div>
3830
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3831<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3832<div class="doc_subsubsection"> <a name="i_and">'<tt>and</tt>'
3833Instruction</a> </div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3834
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3835<div class="doc_text">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3836
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3837<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3838<pre>
Gabor Greif0f75ad02008-08-07 21:46:00 +0000[diff] [blame]3839 &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]3840</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3841
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3842<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3843<p>The '<tt>and</tt>' instruction returns the bitwise logical and of its two
3844 operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3845
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3846<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3847<p>The two arguments to the '<tt>and</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3848 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3849 values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3850
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3851<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3852<p>The truth table used for the '<tt>and</tt>' instruction is:</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3853
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3854<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3855 <tbody>
3856 <tr>
3857 <td>In0</td>
3858 <td>In1</td>
3859 <td>Out</td>
3860 </tr>
3861 <tr>
3862 <td>0</td>
3863 <td>0</td>
3864 <td>0</td>
3865 </tr>
3866 <tr>
3867 <td>0</td>
3868 <td>1</td>
3869 <td>0</td>
3870 </tr>
3871 <tr>
3872 <td>1</td>
3873 <td>0</td>
3874 <td>0</td>
3875 </tr>
3876 <tr>
3877 <td>1</td>
3878 <td>1</td>
3879 <td>1</td>
3880 </tr>
3881 </tbody>
3882</table>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3883
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3884<h5>Example:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3885<pre>
3886 &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]3887 &lt;result&gt; = and i32 15, 40 <i>; yields {i32}:result = 8</i>
3888 &lt;result&gt; = and i32 4, 8 <i>; yields {i32}:result = 0</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3889</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3890</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3891<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3892<div class="doc_subsubsection"> <a name="i_or">'<tt>or</tt>' Instruction</a> </div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3893
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3894<div class="doc_text">
3895
3896<h5>Syntax:</h5>
3897<pre>
3898 &lt;result&gt; = or &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3899</pre>
3900
3901<h5>Overview:</h5>
3902<p>The '<tt>or</tt>' instruction returns the bitwise logical inclusive or of its
3903 two operands.</p>
3904
3905<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3906<p>The two arguments to the '<tt>or</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3907 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3908 values. Both arguments must have identical types.</p>
3909
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3910<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3911<p>The truth table used for the '<tt>or</tt>' instruction is:</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3912
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3913<table border="1" cellspacing="0" cellpadding="4">
3914 <tbody>
3915 <tr>
3916 <td>In0</td>
3917 <td>In1</td>
3918 <td>Out</td>
3919 </tr>
3920 <tr>
3921 <td>0</td>
3922 <td>0</td>
3923 <td>0</td>
3924 </tr>
3925 <tr>
3926 <td>0</td>
3927 <td>1</td>
3928 <td>1</td>
3929 </tr>
3930 <tr>
3931 <td>1</td>
3932 <td>0</td>
3933 <td>1</td>
3934 </tr>
3935 <tr>
3936 <td>1</td>
3937 <td>1</td>
3938 <td>1</td>
3939 </tr>
3940 </tbody>
3941</table>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3942
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3943<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3944<pre>
3945 &lt;result&gt; = or i32 4, %var <i>; yields {i32}:result = 4 | %var</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3946 &lt;result&gt; = or i32 15, 40 <i>; yields {i32}:result = 47</i>
3947 &lt;result&gt; = or i32 4, 8 <i>; yields {i32}:result = 12</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3948</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3949
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3950</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3951
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3952<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3953<div class="doc_subsubsection"> <a name="i_xor">'<tt>xor</tt>'
3954Instruction</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3955
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3956<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3957
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3958<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3959<pre>
3960 &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]3961</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3962
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3963<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3964<p>The '<tt>xor</tt>' instruction returns the bitwise logical exclusive or of
3965 its two operands. The <tt>xor</tt> is used to implement the "one's
3966 complement" operation, which is the "~" operator in C.</p>
3967
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3968<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3969<p>The two arguments to the '<tt>xor</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3970 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3971 values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3972
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3973<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3974<p>The truth table used for the '<tt>xor</tt>' instruction is:</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3975
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3976<table border="1" cellspacing="0" cellpadding="4">
3977 <tbody>
3978 <tr>
3979 <td>In0</td>
3980 <td>In1</td>
3981 <td>Out</td>
3982 </tr>
3983 <tr>
3984 <td>0</td>
3985 <td>0</td>
3986 <td>0</td>
3987 </tr>
3988 <tr>
3989 <td>0</td>
3990 <td>1</td>
3991 <td>1</td>
3992 </tr>
3993 <tr>
3994 <td>1</td>
3995 <td>0</td>
3996 <td>1</td>
3997 </tr>
3998 <tr>
3999 <td>1</td>
4000 <td>1</td>
4001 <td>0</td>
4002 </tr>
4003 </tbody>
4004</table>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4005
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4006<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4007<pre>
4008 &lt;result&gt; = xor i32 4, %var <i>; yields {i32}:result = 4 ^ %var</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4009 &lt;result&gt; = xor i32 15, 40 <i>; yields {i32}:result = 39</i>
4010 &lt;result&gt; = xor i32 4, 8 <i>; yields {i32}:result = 12</i>
4011 &lt;result&gt; = xor i32 %V, -1 <i>; yields {i32}:result = ~%V</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4012</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4013
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4014</div>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4015
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4016<!-- ======================================================================= -->
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4017<div class="doc_subsection">
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4018 <a name="vectorops">Vector Operations</a>
4019</div>
4020
4021<div class="doc_text">
4022
4023<p>LLVM supports several instructions to represent vector operations in a
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4024 target-independent manner. These instructions cover the element-access and
4025 vector-specific operations needed to process vectors effectively. While LLVM
4026 does directly support these vector operations, many sophisticated algorithms
4027 will want to use target-specific intrinsics to take full advantage of a
4028 specific target.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4029
4030</div>
4031
4032<!-- _______________________________________________________________________ -->
4033<div class="doc_subsubsection">
4034 <a name="i_extractelement">'<tt>extractelement</tt>' Instruction</a>
4035</div>
4036
4037<div class="doc_text">
4038
4039<h5>Syntax:</h5>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4040<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4041 &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]4042</pre>
4043
4044<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4045<p>The '<tt>extractelement</tt>' instruction extracts a single scalar element
4046 from a vector at a specified index.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4047
4048
4049<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4050<p>The first operand of an '<tt>extractelement</tt>' instruction is a value
4051 of <a href="#t_vector">vector</a> type. The second operand is an index
4052 indicating the position from which to extract the element. The index may be
4053 a variable.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4054
4055<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4056<p>The result is a scalar of the same type as the element type of
4057 <tt>val</tt>. Its value is the value at position <tt>idx</tt> of
4058 <tt>val</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
4059 results are undefined.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4060
4061<h5>Example:</h5>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4062<pre>
Gabor Greif03ab4dc2009-10-28 13:14:50 +0000[diff] [blame]4063 &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]4064</pre>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4065
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4066</div>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4067
4068<!-- _______________________________________________________________________ -->
4069<div class="doc_subsubsection">
4070 <a name="i_insertelement">'<tt>insertelement</tt>' Instruction</a>
4071</div>
4072
4073<div class="doc_text">
4074
4075<h5>Syntax:</h5>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4076<pre>
Dan Gohman43ba0672008-05-12 23:38:42 +0000[diff] [blame]4077 &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]4078</pre>
4079
4080<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4081<p>The '<tt>insertelement</tt>' instruction inserts a scalar element into a
4082 vector at a specified index.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4083
4084<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4085<p>The first operand of an '<tt>insertelement</tt>' instruction is a value
4086 of <a href="#t_vector">vector</a> type. The second operand is a scalar value
4087 whose type must equal the element type of the first operand. The third
4088 operand is an index indicating the position at which to insert the value.
4089 The index may be a variable.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4090
4091<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4092<p>The result is a vector of the same type as <tt>val</tt>. Its element values
4093 are those of <tt>val</tt> except at position <tt>idx</tt>, where it gets the
4094 value <tt>elt</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
4095 results are undefined.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4096
4097<h5>Example:</h5>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4098<pre>
Gabor Greif03ab4dc2009-10-28 13:14:50 +0000[diff] [blame]4099 &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]4100</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4101
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4102</div>
4103
4104<!-- _______________________________________________________________________ -->
4105<div class="doc_subsubsection">
4106 <a name="i_shufflevector">'<tt>shufflevector</tt>' Instruction</a>
4107</div>
4108
4109<div class="doc_text">
4110
4111<h5>Syntax:</h5>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4112<pre>
Mon P Wang25f01062008-11-10 04:46:22 +0000[diff] [blame]4113 &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]4114</pre>
4115
4116<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4117<p>The '<tt>shufflevector</tt>' instruction constructs a permutation of elements
4118 from two input vectors, returning a vector with the same element type as the
4119 input and length that is the same as the shuffle mask.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4120
4121<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4122<p>The first two operands of a '<tt>shufflevector</tt>' instruction are vectors
4123 with types that match each other. The third argument is a shuffle mask whose
4124 element type is always 'i32'. The result of the instruction is a vector
4125 whose length is the same as the shuffle mask and whose element type is the
4126 same as the element type of the first two operands.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4127
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4128<p>The shuffle mask operand is required to be a constant vector with either
4129 constant integer or undef values.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4130
4131<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4132<p>The elements of the two input vectors are numbered from left to right across
4133 both of the vectors. The shuffle mask operand specifies, for each element of
4134 the result vector, which element of the two input vectors the result element
4135 gets. The element selector may be undef (meaning "don't care") and the
4136 second operand may be undef if performing a shuffle from only one vector.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4137
4138<h5>Example:</h5>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4139<pre>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4140 &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]4141 &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]4142 &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]4143 &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]4144 &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]4145 &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]4146 &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]4147 &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]4148</pre>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4149
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4150</div>
Tanya Lattnerb138bbe2006-04-14 19:24:33 +0000[diff] [blame]4151
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4152<!-- ======================================================================= -->
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4153<div class="doc_subsection">
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4154 <a name="aggregateops">Aggregate Operations</a>
4155</div>
4156
4157<div class="doc_text">
4158
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]4159<p>LLVM supports several instructions for working with
4160 <a href="#t_aggregate">aggregate</a> values.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4161
4162</div>
4163
4164<!-- _______________________________________________________________________ -->
4165<div class="doc_subsubsection">
4166 <a name="i_extractvalue">'<tt>extractvalue</tt>' Instruction</a>
4167</div>
4168
4169<div class="doc_text">
4170
4171<h5>Syntax:</h5>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4172<pre>
4173 &lt;result&gt; = extractvalue &lt;aggregate type&gt; &lt;val&gt;, &lt;idx&gt;{, &lt;idx&gt;}*
4174</pre>
4175
4176<h5>Overview:</h5>
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]4177<p>The '<tt>extractvalue</tt>' instruction extracts the value of a member field
4178 from an <a href="#t_aggregate">aggregate</a> value.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4179
4180<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4181<p>The first operand of an '<tt>extractvalue</tt>' instruction is a value
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]4182 of <a href="#t_struct">struct</a>, <a href="#t_union">union</a> or
4183 <a href="#t_array">array</a> type. The operands are constant indices to
4184 specify which value to extract in a similar manner as indices in a
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4185 '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4186
4187<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4188<p>The result is the value at the position in the aggregate specified by the
4189 index operands.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4190
4191<h5>Example:</h5>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4192<pre>
Gabor Greif03ab4dc2009-10-28 13:14:50 +0000[diff] [blame]4193 &lt;result&gt; = extractvalue {i32, float} %agg, 0 <i>; yields i32</i>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4194</pre>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4195
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4196</div>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4197
4198<!-- _______________________________________________________________________ -->
4199<div class="doc_subsubsection">
4200 <a name="i_insertvalue">'<tt>insertvalue</tt>' Instruction</a>
4201</div>
4202
4203<div class="doc_text">
4204
4205<h5>Syntax:</h5>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4206<pre>
Jeffrey Yasskinf991bbb2010-01-11 19:19:26 +0000[diff] [blame]4207 &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]4208</pre>
4209
4210<h5>Overview:</h5>
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]4211<p>The '<tt>insertvalue</tt>' instruction inserts a value into a member field
4212 in an <a href="#t_aggregate">aggregate</a> value.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4213
4214<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4215<p>The first operand of an '<tt>insertvalue</tt>' instruction is a value
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]4216 of <a href="#t_struct">struct</a>, <a href="#t_union">union</a> or
4217 <a href="#t_array">array</a> type. The second operand is a first-class
4218 value to insert. The following operands are constant indices indicating
4219 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]4220 '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction. The
4221 value to insert must have the same type as the value identified by the
4222 indices.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4223
4224<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4225<p>The result is an aggregate of the same type as <tt>val</tt>. Its value is
4226 that of <tt>val</tt> except that the value at the position specified by the
4227 indices is that of <tt>elt</tt>.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4228
4229<h5>Example:</h5>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4230<pre>
Jeffrey Yasskinf991bbb2010-01-11 19:19:26 +0000[diff] [blame]4231 %agg1 = insertvalue {i32, float} undef, i32 1, 0 <i>; yields {i32 1, float undef}</i>
4232 %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]4233</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4234
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4235</div>
4236
4237
4238<!-- ======================================================================= -->
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4239<div class="doc_subsection">
Chris Lattner6ab66722006-08-15 00:45:58 +0000[diff] [blame]4240 <a name="memoryops">Memory Access and Addressing Operations</a>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4241</div>
4242
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4243<div class="doc_text">
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4244
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4245<p>A key design point of an SSA-based representation is how it represents
4246 memory. In LLVM, no memory locations are in SSA form, which makes things
Victor Hernandeza70c6df2009-10-26 23:44:29 +0000[diff] [blame]4247 very simple. This section describes how to read, write, and allocate
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4248 memory in LLVM.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4249
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4250</div>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4251
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4252<!-- _______________________________________________________________________ -->
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4253<div class="doc_subsubsection">
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4254 <a name="i_alloca">'<tt>alloca</tt>' Instruction</a>
4255</div>
4256
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4257<div class="doc_text">
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4258
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4259<h5>Syntax:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4260<pre>
Dan Gohman2140a742010-05-28 01:14:11 +0000[diff] [blame]4261 &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]4262</pre>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4263
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4264<h5>Overview:</h5>
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]4265<p>The '<tt>alloca</tt>' instruction allocates memory on the stack frame of the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4266 currently executing function, to be automatically released when this function
4267 returns to its caller. The object is always allocated in the generic address
4268 space (address space zero).</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4269
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4270<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4271<p>The '<tt>alloca</tt>' instruction
4272 allocates <tt>sizeof(&lt;type&gt;)*NumElements</tt> bytes of memory on the
4273 runtime stack, returning a pointer of the appropriate type to the program.
4274 If "NumElements" is specified, it is the number of elements allocated,
4275 otherwise "NumElements" is defaulted to be one. If a constant alignment is
4276 specified, the value result of the allocation is guaranteed to be aligned to
4277 at least that boundary. If not specified, or if zero, the target can choose
4278 to align the allocation on any convenient boundary compatible with the
4279 type.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4280
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4281<p>'<tt>type</tt>' may be any sized type.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4282
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4283<h5>Semantics:</h5>
Bill Wendling9ee6a312009-05-08 20:49:29 +0000[diff] [blame]4284<p>Memory is allocated; a pointer is returned. The operation is undefined if
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4285 there is insufficient stack space for the allocation. '<tt>alloca</tt>'d
4286 memory is automatically released when the function returns. The
4287 '<tt>alloca</tt>' instruction is commonly used to represent automatic
4288 variables that must have an address available. When the function returns
4289 (either with the <tt><a href="#i_ret">ret</a></tt>
4290 or <tt><a href="#i_unwind">unwind</a></tt> instructions), the memory is
4291 reclaimed. Allocating zero bytes is legal, but the result is undefined.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4292
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4293<h5>Example:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4294<pre>
Dan Gohman7a5acb52009-01-04 23:49:44 +0000[diff] [blame]4295 %ptr = alloca i32 <i>; yields {i32*}:ptr</i>
4296 %ptr = alloca i32, i32 4 <i>; yields {i32*}:ptr</i>
4297 %ptr = alloca i32, i32 4, align 1024 <i>; yields {i32*}:ptr</i>
4298 %ptr = alloca i32, align 1024 <i>; yields {i32*}:ptr</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4299</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4300
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4301</div>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4302
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4303<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]4304<div class="doc_subsubsection"> <a name="i_load">'<tt>load</tt>'
4305Instruction</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4306
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4307<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4308
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4309<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4310<pre>
Bill Wendlingbc4024f2010-02-25 21:23:24 +0000[diff] [blame]4311 &lt;result&gt; = load &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;][, !nontemporal !&lt;index&gt;]
4312 &lt;result&gt; = volatile load &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;][, !nontemporal !&lt;index&gt;]
4313 !&lt;index&gt; = !{ i32 1 }
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4314</pre>
4315
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4316<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4317<p>The '<tt>load</tt>' instruction is used to read from memory.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4318
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4319<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4320<p>The argument to the '<tt>load</tt>' instruction specifies the memory address
4321 from which to load. The pointer must point to
4322 a <a href="#t_firstclass">first class</a> type. If the <tt>load</tt> is
4323 marked as <tt>volatile</tt>, then the optimizer is not allowed to modify the
Jeffrey Yasskin5d284ae2010-04-26 21:21:24 +0000[diff] [blame]4324 number or order of execution of this <tt>load</tt> with other <a
4325 href="#volatile">volatile operations</a>.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4326
Bill Wendlingbc4024f2010-02-25 21:23:24 +0000[diff] [blame]4327<p>The optional constant <tt>align</tt> argument specifies the alignment of the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4328 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]4329 omitted <tt>align</tt> argument means that the operation has the preferential
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4330 alignment for the target. It is the responsibility of the code emitter to
4331 ensure that the alignment information is correct. Overestimating the
Bill Wendlingbc4024f2010-02-25 21:23:24 +0000[diff] [blame]4332 alignment results in undefined behavior. Underestimating the alignment may
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4333 produce less efficient code. An alignment of 1 is always safe.</p>
4334
Bill Wendlingbc4024f2010-02-25 21:23:24 +0000[diff] [blame]4335<p>The optional <tt>!nontemporal</tt> metadata must reference a single
4336 metatadata name &lt;index&gt; corresponding to a metadata node with
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]4337 one <tt>i32</tt> entry of value 1. The existence of
Bill Wendlingbc4024f2010-02-25 21:23:24 +0000[diff] [blame]4338 the <tt>!nontemporal</tt> metatadata on the instruction tells the optimizer
4339 and code generator that this load is not expected to be reused in the cache.
4340 The code generator may select special instructions to save cache bandwidth,
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]4341 such as the <tt>MOVNT</tt> instruction on x86.</p>
David Greene9641d062010-02-16 20:50:18 +0000[diff] [blame]4342
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4343<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4344<p>The location of memory pointed to is loaded. If the value being loaded is of
4345 scalar type then the number of bytes read does not exceed the minimum number
4346 of bytes needed to hold all bits of the type. For example, loading an
4347 <tt>i24</tt> reads at most three bytes. When loading a value of a type like
4348 <tt>i20</tt> with a size that is not an integral number of bytes, the result
4349 is undefined if the value was not originally written using a store of the
4350 same type.</p>
4351
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4352<h5>Examples:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4353<pre>
4354 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
4355 <a href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4356 %val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4357</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4358
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4359</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4360
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4361<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]4362<div class="doc_subsubsection"> <a name="i_store">'<tt>store</tt>'
4363Instruction</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4364
Reid Spencera89fb182006-11-09 21:18:01 +0000[diff] [blame]4365<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4366
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4367<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4368<pre>
David Greene9641d062010-02-16 20:50:18 +0000[diff] [blame]4369 store &lt;ty&gt; &lt;value&gt;, &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;][, !nontemporal !<index>] <i>; yields {void}</i>
4370 volatile store &lt;ty&gt; &lt;value&gt;, &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;][, !nontemporal !<index>] <i>; yields {void}</i>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4371</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4372
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4373<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4374<p>The '<tt>store</tt>' instruction is used to write to memory.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4375
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4376<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4377<p>There are two arguments to the '<tt>store</tt>' instruction: a value to store
4378 and an address at which to store it. The type of the
4379 '<tt>&lt;pointer&gt;</tt>' operand must be a pointer to
4380 the <a href="#t_firstclass">first class</a> type of the
Jeffrey Yasskin5d284ae2010-04-26 21:21:24 +0000[diff] [blame]4381 '<tt>&lt;value&gt;</tt>' operand. If the <tt>store</tt> is marked as
4382 <tt>volatile</tt>, then the optimizer is not allowed to modify the number or
4383 order of execution of this <tt>store</tt> with other <a
4384 href="#volatile">volatile operations</a>.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4385
4386<p>The optional constant "align" argument specifies the alignment of the
4387 operation (that is, the alignment of the memory address). A value of 0 or an
4388 omitted "align" argument means that the operation has the preferential
4389 alignment for the target. It is the responsibility of the code emitter to
4390 ensure that the alignment information is correct. Overestimating the
4391 alignment results in an undefined behavior. Underestimating the alignment may
4392 produce less efficient code. An alignment of 1 is always safe.</p>
4393
David Greene9641d062010-02-16 20:50:18 +0000[diff] [blame]4394<p>The optional !nontemporal metadata must reference a single metatadata
4395 name <index> corresponding to a metadata node with one i32 entry of
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]4396 value 1. The existence of the !nontemporal metatadata on the
David Greene9641d062010-02-16 20:50:18 +0000[diff] [blame]4397 instruction tells the optimizer and code generator that this load is
4398 not expected to be reused in the cache. The code generator may
4399 select special instructions to save cache bandwidth, such as the
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]4400 MOVNT instruction on x86.</p>
David Greene9641d062010-02-16 20:50:18 +0000[diff] [blame]4401
4402
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]4403<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4404<p>The contents of memory are updated to contain '<tt>&lt;value&gt;</tt>' at the
4405 location specified by the '<tt>&lt;pointer&gt;</tt>' operand. If
4406 '<tt>&lt;value&gt;</tt>' is of scalar type then the number of bytes written
4407 does not exceed the minimum number of bytes needed to hold all bits of the
4408 type. For example, storing an <tt>i24</tt> writes at most three bytes. When
4409 writing a value of a type like <tt>i20</tt> with a size that is not an
4410 integral number of bytes, it is unspecified what happens to the extra bits
4411 that do not belong to the type, but they will typically be overwritten.</p>
4412
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4413<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4414<pre>
4415 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Bill Wendling8830ffe2007-10-22 05:10:05 +0000[diff] [blame]4416 store i32 3, i32* %ptr <i>; yields {void}</i>
4417 %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]4418</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4419
Reid Spencer443460a2006-11-09 21:15:49 +0000[diff] [blame]4420</div>
4421
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4422<!-- _______________________________________________________________________ -->
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4423<div class="doc_subsubsection">
4424 <a name="i_getelementptr">'<tt>getelementptr</tt>' Instruction</a>
4425</div>
4426
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4427<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4428
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]4429<h5>Syntax:</h5>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4430<pre>
Matthijs Kooijman0e268272008-10-13 13:44:15 +0000[diff] [blame]4431 &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]4432 &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]4433</pre>
4434
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]4435<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4436<p>The '<tt>getelementptr</tt>' instruction is used to get the address of a
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]4437 subelement of an <a href="#t_aggregate">aggregate</a> data structure.
4438 It performs address calculation only and does not access memory.</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4439
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]4440<h5>Arguments:</h5>
Matthijs Kooijman0e268272008-10-13 13:44:15 +0000[diff] [blame]4441<p>The first argument is always a pointer, and forms the basis of the
Chris Lattnera40b9122009-07-29 06:44:13 +0000[diff] [blame]4442 calculation. The remaining arguments are indices that indicate which of the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4443 elements of the aggregate object are indexed. The interpretation of each
4444 index is dependent on the type being indexed into. The first index always
4445 indexes the pointer value given as the first argument, the second index
4446 indexes a value of the type pointed to (not necessarily the value directly
4447 pointed to, since the first index can be non-zero), etc. The first type
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]4448 indexed into must be a pointer value, subsequent types can be arrays,
4449 vectors, structs and unions. Note that subsequent types being indexed into
4450 can never be pointers, since that would require loading the pointer before
4451 continuing calculation.</p>
Matthijs Kooijman0e268272008-10-13 13:44:15 +0000[diff] [blame]4452
4453<p>The type of each index argument depends on the type it is indexing into.
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]4454 When indexing into a (optionally packed) structure or union, only <tt>i32</tt>
4455 integer <b>constants</b> are allowed. When indexing into an array, pointer
4456 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]4457 constant.</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4458
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4459<p>For example, let's consider a C code fragment and how it gets compiled to
4460 LLVM:</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4461
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]4462<div class="doc_code">
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4463<pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]4464struct RT {
4465 char A;
Chris Lattnera446f1b2007-05-29 15:43:56 +0000[diff] [blame]4466 int B[10][20];
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]4467 char C;
4468};
4469struct ST {
Chris Lattnera446f1b2007-05-29 15:43:56 +0000[diff] [blame]4470 int X;
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]4471 double Y;
4472 struct RT Z;
4473};
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4474
Chris Lattnera446f1b2007-05-29 15:43:56 +0000[diff] [blame]4475int *foo(struct ST *s) {
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]4476 return &amp;s[1].Z.B[5][13];
4477}
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4478</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]4479</div>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4480
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4481<p>The LLVM code generated by the GCC frontend is:</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4482
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]4483<div class="doc_code">
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4484<pre>
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]4485%RT = <a href="#namedtypes">type</a> { i8 , [10 x [20 x i32]], i8 }
4486%ST = <a href="#namedtypes">type</a> { i32, double, %RT }
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4487
Dan Gohman6b867702009-07-25 02:23:48 +0000[diff] [blame]4488define i32* @foo(%ST* %s) {
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]4489entry:
4490 %reg = getelementptr %ST* %s, i32 1, i32 2, i32 1, i32 5, i32 13
4491 ret i32* %reg
4492}
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4493</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]4494</div>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4495
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]4496<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4497<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]4498 type, which is a pointer, yielding a '<tt>%ST</tt>' = '<tt>{ i32, double, %RT
4499 }</tt>' type, a structure. The second index indexes into the third element
4500 of the structure, yielding a '<tt>%RT</tt>' = '<tt>{ i8 , [10 x [20 x i32]],
4501 i8 }</tt>' type, another structure. The third index indexes into the second
4502 element of the structure, yielding a '<tt>[10 x [20 x i32]]</tt>' type, an
4503 array. The two dimensions of the array are subscripted into, yielding an
4504 '<tt>i32</tt>' type. The '<tt>getelementptr</tt>' instruction returns a
4505 pointer to this element, thus computing a value of '<tt>i32*</tt>' type.</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4506
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4507<p>Note that it is perfectly legal to index partially through a structure,
4508 returning a pointer to an inner element. Because of this, the LLVM code for
4509 the given testcase is equivalent to:</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4510
4511<pre>
Dan Gohman6b867702009-07-25 02:23:48 +0000[diff] [blame]4512 define i32* @foo(%ST* %s) {
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4513 %t1 = getelementptr %ST* %s, i32 1 <i>; yields %ST*:%t1</i>
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]4514 %t2 = getelementptr %ST* %t1, i32 0, i32 2 <i>; yields %RT*:%t2</i>
4515 %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]4516 %t4 = getelementptr [10 x [20 x i32]]* %t3, i32 0, i32 5 <i>; yields [20 x i32]*:%t4</i>
4517 %t5 = getelementptr [20 x i32]* %t4, i32 0, i32 13 <i>; yields i32*:%t5</i>
4518 ret i32* %t5
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4519 }
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]4520</pre>
Chris Lattnerc0ad71e2005-06-24 17:22:57 +0000[diff] [blame]4521
Dan Gohman1639c392009-07-27 21:53:46 +0000[diff] [blame]4522<p>If the <tt>inbounds</tt> keyword is present, the result value of the
Dan Gohman57255802010-04-23 15:23:32 +0000[diff] [blame]4523 <tt>getelementptr</tt> is a <a href="#trapvalues">trap value</a> if the
4524 base pointer is not an <i>in bounds</i> address of an allocated object,
4525 or if any of the addresses that would be formed by successive addition of
4526 the offsets implied by the indices to the base address with infinitely
4527 precise arithmetic are not an <i>in bounds</i> address of that allocated
4528 object. The <i>in bounds</i> addresses for an allocated object are all
4529 the addresses that point into the object, plus the address one byte past
4530 the end.</p>
Dan Gohman1639c392009-07-27 21:53:46 +0000[diff] [blame]4531
4532<p>If the <tt>inbounds</tt> keyword is not present, the offsets are added to
4533 the base address with silently-wrapping two's complement arithmetic, and
4534 the result value of the <tt>getelementptr</tt> may be outside the object
4535 pointed to by the base pointer. The result value may not necessarily be
4536 used to access memory though, even if it happens to point into allocated
4537 storage. See the <a href="#pointeraliasing">Pointer Aliasing Rules</a>
4538 section for more information.</p>
4539
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4540<p>The getelementptr instruction is often confusing. For some more insight into
4541 how it works, see <a href="GetElementPtr.html">the getelementptr FAQ</a>.</p>
Chris Lattner6ab66722006-08-15 00:45:58 +0000[diff] [blame]4542
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]4543<h5>Example:</h5>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4544<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4545 <i>; yields [12 x i8]*:aptr</i>
Matthijs Kooijman0e268272008-10-13 13:44:15 +0000[diff] [blame]4546 %aptr = getelementptr {i32, [12 x i8]}* %saptr, i64 0, i32 1
4547 <i>; yields i8*:vptr</i>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]4548 %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]4549 <i>; yields i8*:eptr</i>
4550 %eptr = getelementptr [12 x i8]* %aptr, i64 0, i32 1
Sanjiv Gupta0c155e62009-04-25 07:27:44 +0000[diff] [blame]4551 <i>; yields i32*:iptr</i>
Sanjiv Gupta77abea02009-04-24 16:38:13 +0000[diff] [blame]4552 %iptr = getelementptr [10 x i32]* @arr, i16 0, i16 0
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4553</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4554
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4555</div>
Reid Spencer443460a2006-11-09 21:15:49 +0000[diff] [blame]4556
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4557<!-- ======================================================================= -->
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]4558<div class="doc_subsection"> <a name="convertops">Conversion Operations</a>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4559</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4560
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4561<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4562
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]4563<p>The instructions in this category are the conversion instructions (casting)
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4564 which all take a single operand and a type. They perform various bit
4565 conversions on the operand.</p>
4566
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4567</div>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]4568
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]4569<!-- _______________________________________________________________________ -->
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]4570<div class="doc_subsubsection">
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4571 <a name="i_trunc">'<tt>trunc .. to</tt>' Instruction</a>
4572</div>
4573<div class="doc_text">
4574
4575<h5>Syntax:</h5>
4576<pre>
4577 &lt;result&gt; = trunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4578</pre>
4579
4580<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4581<p>The '<tt>trunc</tt>' instruction truncates its operand to the
4582 type <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4583
4584<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4585<p>The '<tt>trunc</tt>' instruction takes a <tt>value</tt> to trunc, which must
4586 be an <a href="#t_integer">integer</a> type, and a type that specifies the
4587 size and type of the result, which must be
4588 an <a href="#t_integer">integer</a> type. The bit size of <tt>value</tt> must
4589 be larger than the bit size of <tt>ty2</tt>. Equal sized types are not
4590 allowed.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4591
4592<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4593<p>The '<tt>trunc</tt>' instruction truncates the high order bits
4594 in <tt>value</tt> and converts the remaining bits to <tt>ty2</tt>. Since the
4595 source size must be larger than the destination size, <tt>trunc</tt> cannot
4596 be a <i>no-op cast</i>. It will always truncate bits.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4597
4598<h5>Example:</h5>
4599<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4600 %X = trunc i32 257 to i8 <i>; yields i8:1</i>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]4601 %Y = trunc i32 123 to i1 <i>; yields i1:true</i>
Gabor Greiff50fd572009-10-28 09:21:30 +0000[diff] [blame]4602 %Z = trunc i32 122 to i1 <i>; yields i1:false</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4603</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4604
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4605</div>
4606
4607<!-- _______________________________________________________________________ -->
4608<div class="doc_subsubsection">
4609 <a name="i_zext">'<tt>zext .. to</tt>' Instruction</a>
4610</div>
4611<div class="doc_text">
4612
4613<h5>Syntax:</h5>
4614<pre>
4615 &lt;result&gt; = zext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4616</pre>
4617
4618<h5>Overview:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4619<p>The '<tt>zext</tt>' instruction zero extends its operand to type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4620 <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4621
4622
4623<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4624<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]4625 <a href="#t_integer">integer</a> type, and a type to cast it to, which must
4626 also be of <a href="#t_integer">integer</a> type. The bit size of the
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4627 <tt>value</tt> must be smaller than the bit size of the destination type,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4628 <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4629
4630<h5>Semantics:</h5>
4631<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]4632 bits until it reaches the size of the destination type, <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4633
Reid Spencer07c9c682007-01-12 15:46:11 +0000[diff] [blame]4634<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]4635
4636<h5>Example:</h5>
4637<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4638 %X = zext i32 257 to i64 <i>; yields i64:257</i>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]4639 %Y = zext i1 true to i32 <i>; yields i32:1</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4640</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4641
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4642</div>
4643
4644<!-- _______________________________________________________________________ -->
4645<div class="doc_subsubsection">
4646 <a name="i_sext">'<tt>sext .. to</tt>' Instruction</a>
4647</div>
4648<div class="doc_text">
4649
4650<h5>Syntax:</h5>
4651<pre>
4652 &lt;result&gt; = sext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4653</pre>
4654
4655<h5>Overview:</h5>
4656<p>The '<tt>sext</tt>' sign extends <tt>value</tt> to the type <tt>ty2</tt>.</p>
4657
4658<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4659<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]4660 <a href="#t_integer">integer</a> type, and a type to cast it to, which must
4661 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]4662 <tt>value</tt> must be smaller than the bit size of the destination type,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4663 <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4664
4665<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4666<p>The '<tt>sext</tt>' instruction performs a sign extension by copying the sign
4667 bit (highest order bit) of the <tt>value</tt> until it reaches the bit size
4668 of the type <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4669
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]4670<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]4671
4672<h5>Example:</h5>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4673<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4674 %X = sext i8 -1 to i16 <i>; yields i16 :65535</i>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]4675 %Y = sext i1 true to i32 <i>; yields i32:-1</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4676</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4677
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4678</div>
4679
4680<!-- _______________________________________________________________________ -->
4681<div class="doc_subsubsection">
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]4682 <a name="i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a>
4683</div>
4684
4685<div class="doc_text">
4686
4687<h5>Syntax:</h5>
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]4688<pre>
4689 &lt;result&gt; = fptrunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4690</pre>
4691
4692<h5>Overview:</h5>
4693<p>The '<tt>fptrunc</tt>' instruction truncates <tt>value</tt> to type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4694 <tt>ty2</tt>.</p>
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]4695
4696<h5>Arguments:</h5>
4697<p>The '<tt>fptrunc</tt>' instruction takes a <a href="#t_floating">floating
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4698 point</a> value to cast and a <a href="#t_floating">floating point</a> type
4699 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]4700 <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]4701 <i>no-op cast</i>.</p>
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]4702
4703<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4704<p>The '<tt>fptrunc</tt>' instruction truncates a <tt>value</tt> from a larger
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4705 <a href="#t_floating">floating point</a> type to a smaller
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4706 <a href="#t_floating">floating point</a> type. If the value cannot fit
4707 within the destination type, <tt>ty2</tt>, then the results are
4708 undefined.</p>
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]4709
4710<h5>Example:</h5>
4711<pre>
4712 %X = fptrunc double 123.0 to float <i>; yields float:123.0</i>
4713 %Y = fptrunc double 1.0E+300 to float <i>; yields undefined</i>
4714</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4715
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]4716</div>
4717
4718<!-- _______________________________________________________________________ -->
4719<div class="doc_subsubsection">
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4720 <a name="i_fpext">'<tt>fpext .. to</tt>' Instruction</a>
4721</div>
4722<div class="doc_text">
4723
4724<h5>Syntax:</h5>
4725<pre>
4726 &lt;result&gt; = fpext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4727</pre>
4728
4729<h5>Overview:</h5>
4730<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]4731 floating point value.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4732
4733<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4734<p>The '<tt>fpext</tt>' instruction takes a
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4735 <a href="#t_floating">floating point</a> <tt>value</tt> to cast, and
4736 a <a href="#t_floating">floating point</a> type to cast it to. The source
4737 type must be smaller than the destination type.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4738
4739<h5>Semantics:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]4740<p>The '<tt>fpext</tt>' instruction extends the <tt>value</tt> from a smaller
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4741 <a href="#t_floating">floating point</a> type to a larger
4742 <a href="#t_floating">floating point</a> type. The <tt>fpext</tt> cannot be
4743 used to make a <i>no-op cast</i> because it always changes bits. Use
4744 <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]4745
4746<h5>Example:</h5>
4747<pre>
4748 %X = fpext float 3.1415 to double <i>; yields double:3.1415</i>
4749 %Y = fpext float 1.0 to float <i>; yields float:1.0 (no-op)</i>
4750</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4751
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4752</div>
4753
4754<!-- _______________________________________________________________________ -->
4755<div class="doc_subsubsection">
Reid Spencer2eadb532007-01-21 00:29:26 +0000[diff] [blame]4756 <a name="i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4757</div>
4758<div class="doc_text">
4759
4760<h5>Syntax:</h5>
4761<pre>
Reid Spencer753163d2007-07-31 14:40:14 +0000[diff] [blame]4762 &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]4763</pre>
4764
4765<h5>Overview:</h5>
Reid Spencer753163d2007-07-31 14:40:14 +0000[diff] [blame]4766<p>The '<tt>fptoui</tt>' converts a floating point <tt>value</tt> to its
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4767 unsigned integer equivalent of type <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4768
4769<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4770<p>The '<tt>fptoui</tt>' instruction takes a value to cast, which must be a
4771 scalar or vector <a href="#t_floating">floating point</a> value, and a type
4772 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
4773 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
4774 vector integer type with the same number of elements as <tt>ty</tt></p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4775
4776<h5>Semantics:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4777<p>The '<tt>fptoui</tt>' instruction converts its
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4778 <a href="#t_floating">floating point</a> operand into the nearest (rounding
4779 towards zero) unsigned integer value. If the value cannot fit
4780 in <tt>ty2</tt>, the results are undefined.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4781
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4782<h5>Example:</h5>
4783<pre>
Reid Spencer753163d2007-07-31 14:40:14 +0000[diff] [blame]4784 %X = fptoui double 123.0 to i32 <i>; yields i32:123</i>
Chris Lattner5b95a172007-09-22 03:17:52 +0000[diff] [blame]4785 %Y = fptoui float 1.0E+300 to i1 <i>; yields undefined:1</i>
Gabor Greiff50fd572009-10-28 09:21:30 +0000[diff] [blame]4786 %Z = fptoui float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4787</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4788
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4789</div>
4790
4791<!-- _______________________________________________________________________ -->
4792<div class="doc_subsubsection">
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]4793 <a name="i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4794</div>
4795<div class="doc_text">
4796
4797<h5>Syntax:</h5>
4798<pre>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]4799 &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]4800</pre>
4801
4802<h5>Overview:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4803<p>The '<tt>fptosi</tt>' instruction converts
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4804 <a href="#t_floating">floating point</a> <tt>value</tt> to
4805 type <tt>ty2</tt>.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]4806
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]4807<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4808<p>The '<tt>fptosi</tt>' instruction takes a value to cast, which must be a
4809 scalar or vector <a href="#t_floating">floating point</a> value, and a type
4810 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
4811 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
4812 vector integer type with the same number of elements as <tt>ty</tt></p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]4813
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]4814<h5>Semantics:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4815<p>The '<tt>fptosi</tt>' instruction converts its
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4816 <a href="#t_floating">floating point</a> operand into the nearest (rounding
4817 towards zero) signed integer value. If the value cannot fit in <tt>ty2</tt>,
4818 the results are undefined.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]4819
Chris Lattner70de6632001-07-09 00:26:23 +0000[diff] [blame]4820<h5>Example:</h5>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]4821<pre>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]4822 %X = fptosi double -123.0 to i32 <i>; yields i32:-123</i>
Chris Lattner5b95a172007-09-22 03:17:52 +0000[diff] [blame]4823 %Y = fptosi float 1.0E-247 to i1 <i>; yields undefined:1</i>
Gabor Greiff50fd572009-10-28 09:21:30 +0000[diff] [blame]4824 %Z = fptosi float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4825</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4826
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4827</div>
4828
4829<!-- _______________________________________________________________________ -->
4830<div class="doc_subsubsection">
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]4831 <a name="i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4832</div>
4833<div class="doc_text">
4834
4835<h5>Syntax:</h5>
4836<pre>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]4837 &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]4838</pre>
4839
4840<h5>Overview:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]4841<p>The '<tt>uitofp</tt>' instruction regards <tt>value</tt> as an unsigned
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4842 integer and converts that value to the <tt>ty2</tt> type.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4843
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4844<h5>Arguments:</h5>
Nate Begemand4d45c22007-11-17 03:58:34 +0000[diff] [blame]4845<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]4846 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
4847 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
4848 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
4849 floating point type with the same number of elements as <tt>ty</tt></p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4850
4851<h5>Semantics:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]4852<p>The '<tt>uitofp</tt>' instruction interprets its operand as an unsigned
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4853 integer quantity and converts it to the corresponding floating point
4854 value. If the value cannot fit in the floating point value, the results are
4855 undefined.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4856
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4857<h5>Example:</h5>
4858<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4859 %X = uitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]4860 %Y = uitofp i8 -1 to double <i>; yields double:255.0</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4861</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4862
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4863</div>
4864
4865<!-- _______________________________________________________________________ -->
4866<div class="doc_subsubsection">
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]4867 <a name="i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4868</div>
4869<div class="doc_text">
4870
4871<h5>Syntax:</h5>
4872<pre>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]4873 &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]4874</pre>
4875
4876<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4877<p>The '<tt>sitofp</tt>' instruction regards <tt>value</tt> as a signed integer
4878 and converts that value to the <tt>ty2</tt> type.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4879
4880<h5>Arguments:</h5>
Nate Begemand4d45c22007-11-17 03:58:34 +0000[diff] [blame]4881<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]4882 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
4883 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
4884 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
4885 floating point type with the same number of elements as <tt>ty</tt></p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4886
4887<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4888<p>The '<tt>sitofp</tt>' instruction interprets its operand as a signed integer
4889 quantity and converts it to the corresponding floating point value. If the
4890 value cannot fit in the floating point value, the results are undefined.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4891
4892<h5>Example:</h5>
4893<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4894 %X = sitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]4895 %Y = sitofp i8 -1 to double <i>; yields double:-1.0</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4896</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4897
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4898</div>
4899
4900<!-- _______________________________________________________________________ -->
4901<div class="doc_subsubsection">
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]4902 <a name="i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a>
4903</div>
4904<div class="doc_text">
4905
4906<h5>Syntax:</h5>
4907<pre>
4908 &lt;result&gt; = ptrtoint &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4909</pre>
4910
4911<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4912<p>The '<tt>ptrtoint</tt>' instruction converts the pointer <tt>value</tt> to
4913 the integer type <tt>ty2</tt>.</p>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]4914
4915<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4916<p>The '<tt>ptrtoint</tt>' instruction takes a <tt>value</tt> to cast, which
4917 must be a <a href="#t_pointer">pointer</a> value, and a type to cast it to
4918 <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]4919
4920<h5>Semantics:</h5>
4921<p>The '<tt>ptrtoint</tt>' instruction converts <tt>value</tt> to integer type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4922 <tt>ty2</tt> by interpreting the pointer value as an integer and either
4923 truncating or zero extending that value to the size of the integer type. If
4924 <tt>value</tt> is smaller than <tt>ty2</tt> then a zero extension is done. If
4925 <tt>value</tt> is larger than <tt>ty2</tt> then a truncation is done. If they
4926 are the same size, then nothing is done (<i>no-op cast</i>) other than a type
4927 change.</p>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]4928
4929<h5>Example:</h5>
4930<pre>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]4931 %X = ptrtoint i32* %X to i8 <i>; yields truncation on 32-bit architecture</i>
4932 %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]4933</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4934
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]4935</div>
4936
4937<!-- _______________________________________________________________________ -->
4938<div class="doc_subsubsection">
4939 <a name="i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a>
4940</div>
4941<div class="doc_text">
4942
4943<h5>Syntax:</h5>
4944<pre>
4945 &lt;result&gt; = inttoptr &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4946</pre>
4947
4948<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4949<p>The '<tt>inttoptr</tt>' instruction converts an integer <tt>value</tt> to a
4950 pointer type, <tt>ty2</tt>.</p>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]4951
4952<h5>Arguments:</h5>
Duncan Sands16f122e2007-03-30 12:22:09 +0000[diff] [blame]4953<p>The '<tt>inttoptr</tt>' instruction takes an <a href="#t_integer">integer</a>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4954 value to cast, and a type to cast it to, which must be a
4955 <a href="#t_pointer">pointer</a> type.</p>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]4956
4957<h5>Semantics:</h5>
4958<p>The '<tt>inttoptr</tt>' instruction converts <tt>value</tt> to type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4959 <tt>ty2</tt> by applying either a zero extension or a truncation depending on
4960 the size of the integer <tt>value</tt>. If <tt>value</tt> is larger than the
4961 size of a pointer then a truncation is done. If <tt>value</tt> is smaller
4962 than the size of a pointer then a zero extension is done. If they are the
4963 same size, nothing is done (<i>no-op cast</i>).</p>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]4964
4965<h5>Example:</h5>
4966<pre>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]4967 %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]4968 %Y = inttoptr i32 255 to i32* <i>; yields no-op on 32-bit architecture</i>
4969 %Z = inttoptr i64 0 to i32* <i>; yields truncation on 32-bit architecture</i>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]4970</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4971
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]4972</div>
4973
4974<!-- _______________________________________________________________________ -->
4975<div class="doc_subsubsection">
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]4976 <a name="i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4977</div>
4978<div class="doc_text">
4979
4980<h5>Syntax:</h5>
4981<pre>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]4982 &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]4983</pre>
4984
4985<h5>Overview:</h5>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]4986<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4987 <tt>ty2</tt> without changing any bits.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4988
4989<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4990<p>The '<tt>bitcast</tt>' instruction takes a value to cast, which must be a
4991 non-aggregate first class value, and a type to cast it to, which must also be
4992 a non-aggregate <a href="#t_firstclass">first class</a> type. The bit sizes
4993 of <tt>value</tt> and the destination type, <tt>ty2</tt>, must be
4994 identical. If the source type is a pointer, the destination type must also be
4995 a pointer. This instruction supports bitwise conversion of vectors to
4996 integers and to vectors of other types (as long as they have the same
4997 size).</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4998
4999<h5>Semantics:</h5>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]5000<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5001 <tt>ty2</tt>. It is always a <i>no-op cast</i> because no bits change with
5002 this conversion. The conversion is done as if the <tt>value</tt> had been
5003 stored to memory and read back as type <tt>ty2</tt>. Pointer types may only
5004 be converted to other pointer types with this instruction. To convert
5005 pointers to other types, use the <a href="#i_inttoptr">inttoptr</a> or
5006 <a href="#i_ptrtoint">ptrtoint</a> instructions first.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5007
5008<h5>Example:</h5>
5009<pre>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5010 %X = bitcast i8 255 to i8 <i>; yields i8 :-1</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]5011 %Y = bitcast i32* %x to sint* <i>; yields sint*:%x</i>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5012 %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]5013</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5014
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5015</div>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5016
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5017<!-- ======================================================================= -->
5018<div class="doc_subsection"> <a name="otherops">Other Operations</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5019
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5020<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5021
5022<p>The instructions in this category are the "miscellaneous" instructions, which
5023 defy better classification.</p>
5024
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5025</div>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5026
5027<!-- _______________________________________________________________________ -->
5028<div class="doc_subsubsection"><a name="i_icmp">'<tt>icmp</tt>' Instruction</a>
5029</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5030
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5031<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5032
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5033<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5034<pre>
5035 &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]5036</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5037
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5038<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5039<p>The '<tt>icmp</tt>' instruction returns a boolean value or a vector of
5040 boolean values based on comparison of its two integer, integer vector, or
5041 pointer operands.</p>
5042
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5043<h5>Arguments:</h5>
5044<p>The '<tt>icmp</tt>' instruction takes three operands. The first operand is
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5045 the condition code indicating the kind of comparison to perform. It is not a
5046 value, just a keyword. The possible condition code are:</p>
5047
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5048<ol>
5049 <li><tt>eq</tt>: equal</li>
5050 <li><tt>ne</tt>: not equal </li>
5051 <li><tt>ugt</tt>: unsigned greater than</li>
5052 <li><tt>uge</tt>: unsigned greater or equal</li>
5053 <li><tt>ult</tt>: unsigned less than</li>
5054 <li><tt>ule</tt>: unsigned less or equal</li>
5055 <li><tt>sgt</tt>: signed greater than</li>
5056 <li><tt>sge</tt>: signed greater or equal</li>
5057 <li><tt>slt</tt>: signed less than</li>
5058 <li><tt>sle</tt>: signed less or equal</li>
5059</ol>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5060
Chris Lattnerc0f423a2007-01-15 01:54:13 +0000[diff] [blame]5061<p>The remaining two arguments must be <a href="#t_integer">integer</a> or
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5062 <a href="#t_pointer">pointer</a> or integer <a href="#t_vector">vector</a>
5063 typed. They must also be identical types.</p>
5064
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5065<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5066<p>The '<tt>icmp</tt>' compares <tt>op1</tt> and <tt>op2</tt> according to the
5067 condition code given as <tt>cond</tt>. The comparison performed always yields
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]5068 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]5069 result, as follows:</p>
5070
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5071<ol>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5072 <li><tt>eq</tt>: yields <tt>true</tt> if the operands are equal,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5073 <tt>false</tt> otherwise. No sign interpretation is necessary or
5074 performed.</li>
5075
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5076 <li><tt>ne</tt>: yields <tt>true</tt> if the operands are unequal,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5077 <tt>false</tt> otherwise. No sign interpretation is necessary or
5078 performed.</li>
5079
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5080 <li><tt>ugt</tt>: interprets the operands as unsigned values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5081 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
5082
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5083 <li><tt>uge</tt>: interprets the operands as unsigned values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5084 <tt>true</tt> if <tt>op1</tt> is greater than or equal
5085 to <tt>op2</tt>.</li>
5086
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5087 <li><tt>ult</tt>: interprets the operands as unsigned values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5088 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
5089
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5090 <li><tt>ule</tt>: interprets the operands as unsigned values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5091 <tt>true</tt> if <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
5092
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5093 <li><tt>sgt</tt>: interprets the operands as signed values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5094 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
5095
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5096 <li><tt>sge</tt>: interprets the operands as signed values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5097 <tt>true</tt> if <tt>op1</tt> is greater than or equal
5098 to <tt>op2</tt>.</li>
5099
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5100 <li><tt>slt</tt>: interprets the operands as signed values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5101 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
5102
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5103 <li><tt>sle</tt>: interprets the operands as signed values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5104 <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]5105</ol>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5106
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5107<p>If the operands are <a href="#t_pointer">pointer</a> typed, the pointer
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5108 values are compared as if they were integers.</p>
5109
5110<p>If the operands are integer vectors, then they are compared element by
5111 element. The result is an <tt>i1</tt> vector with the same number of elements
5112 as the values being compared. Otherwise, the result is an <tt>i1</tt>.</p>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5113
5114<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5115<pre>
5116 &lt;result&gt; = icmp eq i32 4, 5 <i>; yields: result=false</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]5117 &lt;result&gt; = icmp ne float* %X, %X <i>; yields: result=false</i>
5118 &lt;result&gt; = icmp ult i16 4, 5 <i>; yields: result=true</i>
5119 &lt;result&gt; = icmp sgt i16 4, 5 <i>; yields: result=false</i>
5120 &lt;result&gt; = icmp ule i16 -4, 5 <i>; yields: result=false</i>
5121 &lt;result&gt; = icmp sge i16 4, 5 <i>; yields: result=false</i>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5122</pre>
Dan Gohmana5127ab2009-01-22 01:39:38 +0000[diff] [blame]5123
5124<p>Note that the code generator does not yet support vector types with
5125 the <tt>icmp</tt> instruction.</p>
5126
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5127</div>
5128
5129<!-- _______________________________________________________________________ -->
5130<div class="doc_subsubsection"><a name="i_fcmp">'<tt>fcmp</tt>' Instruction</a>
5131</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5132
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5133<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5134
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5135<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5136<pre>
5137 &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]5138</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5139
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5140<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5141<p>The '<tt>fcmp</tt>' instruction returns a boolean value or vector of boolean
5142 values based on comparison of its operands.</p>
5143
5144<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]5145(<a href="#t_integer"><tt>i1</tt></a>).</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5146
5147<p>If the operands are floating point vectors, then the result type is a vector
5148 of boolean with the same number of elements as the operands being
5149 compared.</p>
5150
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5151<h5>Arguments:</h5>
5152<p>The '<tt>fcmp</tt>' instruction takes three operands. The first operand is
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5153 the condition code indicating the kind of comparison to perform. It is not a
5154 value, just a keyword. The possible condition code are:</p>
5155
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5156<ol>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]5157 <li><tt>false</tt>: no comparison, always returns false</li>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5158 <li><tt>oeq</tt>: ordered and equal</li>
5159 <li><tt>ogt</tt>: ordered and greater than </li>
5160 <li><tt>oge</tt>: ordered and greater than or equal</li>
5161 <li><tt>olt</tt>: ordered and less than </li>
5162 <li><tt>ole</tt>: ordered and less than or equal</li>
5163 <li><tt>one</tt>: ordered and not equal</li>
5164 <li><tt>ord</tt>: ordered (no nans)</li>
5165 <li><tt>ueq</tt>: unordered or equal</li>
5166 <li><tt>ugt</tt>: unordered or greater than </li>
5167 <li><tt>uge</tt>: unordered or greater than or equal</li>
5168 <li><tt>ult</tt>: unordered or less than </li>
5169 <li><tt>ule</tt>: unordered or less than or equal</li>
5170 <li><tt>une</tt>: unordered or not equal</li>
5171 <li><tt>uno</tt>: unordered (either nans)</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]5172 <li><tt>true</tt>: no comparison, always returns true</li>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5173</ol>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5174
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5175<p><i>Ordered</i> means that neither operand is a QNAN while
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5176 <i>unordered</i> means that either operand may be a QNAN.</p>
5177
5178<p>Each of <tt>val1</tt> and <tt>val2</tt> arguments must be either
5179 a <a href="#t_floating">floating point</a> type or
5180 a <a href="#t_vector">vector</a> of floating point type. They must have
5181 identical types.</p>
5182
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5183<h5>Semantics:</h5>
Gabor Greif0f75ad02008-08-07 21:46:00 +0000[diff] [blame]5184<p>The '<tt>fcmp</tt>' instruction compares <tt>op1</tt> and <tt>op2</tt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5185 according to the condition code given as <tt>cond</tt>. If the operands are
5186 vectors, then the vectors are compared element by element. Each comparison
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]5187 performed always yields an <a href="#t_integer">i1</a> result, as
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5188 follows:</p>
5189
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5190<ol>
5191 <li><tt>false</tt>: always yields <tt>false</tt>, regardless of operands.</li>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5192
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5193 <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]5194 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
5195
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]5196 <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]5197 <tt>op1</tt> is greater than <tt>op2</tt>.</li>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5198
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5199 <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]5200 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
5201
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5202 <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]5203 <tt>op1</tt> is less than <tt>op2</tt>.</li>
5204
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5205 <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]5206 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
5207
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5208 <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]5209 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
5210
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]5211 <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]5212
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5213 <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]5214 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
5215
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5216 <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]5217 <tt>op1</tt> is greater than <tt>op2</tt>.</li>
5218
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5219 <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]5220 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
5221
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5222 <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]5223 <tt>op1</tt> is less than <tt>op2</tt>.</li>
5224
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5225 <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]5226 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
5227
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5228 <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]5229 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
5230
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]5231 <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]5232
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5233 <li><tt>true</tt>: always yields <tt>true</tt>, regardless of operands.</li>
5234</ol>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5235
5236<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5237<pre>
5238 &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]5239 &lt;result&gt; = fcmp one float 4.0, 5.0 <i>; yields: result=true</i>
5240 &lt;result&gt; = fcmp olt float 4.0, 5.0 <i>; yields: result=true</i>
5241 &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]5242</pre>
Dan Gohmana5127ab2009-01-22 01:39:38 +0000[diff] [blame]5243
5244<p>Note that the code generator does not yet support vector types with
5245 the <tt>fcmp</tt> instruction.</p>
5246
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5247</div>
5248
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5249<!-- _______________________________________________________________________ -->
Nate Begemand2195702008-05-12 19:01:56 +0000[diff] [blame]5250<div class="doc_subsubsection">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]5251 <a name="i_phi">'<tt>phi</tt>' Instruction</a>
5252</div>
5253
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5254<div class="doc_text">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]5255
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5256<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5257<pre>
5258 &lt;result&gt; = phi &lt;ty&gt; [ &lt;val0&gt;, &lt;label0&gt;], ...
5259</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]5260
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5261<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5262<p>The '<tt>phi</tt>' instruction is used to implement the &#966; node in the
5263 SSA graph representing the function.</p>
5264
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5265<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5266<p>The type of the incoming values is specified with the first type field. After
5267 this, the '<tt>phi</tt>' instruction takes a list of pairs as arguments, with
5268 one pair for each predecessor basic block of the current block. Only values
5269 of <a href="#t_firstclass">first class</a> type may be used as the value
5270 arguments to the PHI node. Only labels may be used as the label
5271 arguments.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]5272
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5273<p>There must be no non-phi instructions between the start of a basic block and
5274 the PHI instructions: i.e. PHI instructions must be first in a basic
5275 block.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]5276
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5277<p>For the purposes of the SSA form, the use of each incoming value is deemed to
5278 occur on the edge from the corresponding predecessor block to the current
5279 block (but after any definition of an '<tt>invoke</tt>' instruction's return
5280 value on the same edge).</p>
Jay Foad1a4eea52009-06-03 10:20:10 +0000[diff] [blame]5281
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5282<h5>Semantics:</h5>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5283<p>At runtime, the '<tt>phi</tt>' instruction logically takes on the value
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5284 specified by the pair corresponding to the predecessor basic block that
5285 executed just prior to the current block.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]5286
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5287<h5>Example:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]5288<pre>
5289Loop: ; Infinite loop that counts from 0 on up...
5290 %indvar = phi i32 [ 0, %LoopHeader ], [ %nextindvar, %Loop ]
5291 %nextindvar = add i32 %indvar, 1
5292 br label %Loop
5293</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5294
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5295</div>
5296
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5297<!-- _______________________________________________________________________ -->
5298<div class="doc_subsubsection">
5299 <a name="i_select">'<tt>select</tt>' Instruction</a>
5300</div>
5301
5302<div class="doc_text">
5303
5304<h5>Syntax:</h5>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5305<pre>
Dan Gohmanc579d972008-09-09 01:02:47 +0000[diff] [blame]5306 &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>
5307
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]5308 <i>selty</i> is either i1 or {&lt;N x i1&gt;}
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5309</pre>
5310
5311<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5312<p>The '<tt>select</tt>' instruction is used to choose one value based on a
5313 condition, without branching.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5314
5315
5316<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5317<p>The '<tt>select</tt>' instruction requires an 'i1' value or a vector of 'i1'
5318 values indicating the condition, and two values of the
5319 same <a href="#t_firstclass">first class</a> type. If the val1/val2 are
5320 vectors and the condition is a scalar, then entire vectors are selected, not
5321 individual elements.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5322
5323<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5324<p>If the condition is an i1 and it evaluates to 1, the instruction returns the
5325 first value argument; otherwise, it returns the second value argument.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5326
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5327<p>If the condition is a vector of i1, then the value arguments must be vectors
5328 of the same size, and the selection is done element by element.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5329
5330<h5>Example:</h5>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5331<pre>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]5332 %X = select i1 true, i8 17, i8 42 <i>; yields i8:17</i>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5333</pre>
Dan Gohmana5127ab2009-01-22 01:39:38 +0000[diff] [blame]5334
5335<p>Note that the code generator does not yet support conditions
5336 with vector type.</p>
5337
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5338</div>
5339
Robert Bocchinof72fdfe2006-01-15 20:48:27 +0000[diff] [blame]5340<!-- _______________________________________________________________________ -->
5341<div class="doc_subsubsection">
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5342 <a name="i_call">'<tt>call</tt>' Instruction</a>
5343</div>
5344
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5345<div class="doc_text">
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5346
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]5347<h5>Syntax:</h5>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5348<pre>
Devang Patel02256232008-10-07 17:48:33 +0000[diff] [blame]5349 &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]5350</pre>
5351
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]5352<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5353<p>The '<tt>call</tt>' instruction represents a simple function call.</p>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5354
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]5355<h5>Arguments:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5356<p>This instruction requires several arguments:</p>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5357
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]5358<ol>
Jeffrey Yasskinb8677462010-01-09 19:44:16 +0000[diff] [blame]5359 <li>The optional "tail" marker indicates that the callee function does not
5360 access any allocas or varargs in the caller. Note that calls may be
5361 marked "tail" even if they do not occur before
5362 a <a href="#i_ret"><tt>ret</tt></a> instruction. If the "tail" marker is
5363 present, the function call is eligible for tail call optimization,
5364 but <a href="CodeGenerator.html#tailcallopt">might not in fact be
Evan Cheng59676492010-03-08 21:05:02 +0000[diff] [blame]5365 optimized into a jump</a>. The code generator may optimize calls marked
5366 "tail" with either 1) automatic <a href="CodeGenerator.html#sibcallopt">
5367 sibling call optimization</a> when the caller and callee have
5368 matching signatures, or 2) forced tail call optimization when the
5369 following extra requirements are met:
Jeffrey Yasskinb8677462010-01-09 19:44:16 +0000[diff] [blame]5370 <ul>
5371 <li>Caller and callee both have the calling
5372 convention <tt>fastcc</tt>.</li>
5373 <li>The call is in tail position (ret immediately follows call and ret
5374 uses value of call or is void).</li>
5375 <li>Option <tt>-tailcallopt</tt> is enabled,
Dan Gohman6232f732010-03-02 01:08:11 +0000[diff] [blame]5376 or <code>llvm::GuaranteedTailCallOpt</code> is <code>true</code>.</li>
Jeffrey Yasskinb8677462010-01-09 19:44:16 +0000[diff] [blame]5377 <li><a href="CodeGenerator.html#tailcallopt">Platform specific
5378 constraints are met.</a></li>
5379 </ul>
5380 </li>
Devang Patel7e9b05e2008-10-06 18:50:38 +0000[diff] [blame]5381
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5382 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
5383 convention</a> the call should use. If none is specified, the call
Jeffrey Yasskinb8677462010-01-09 19:44:16 +0000[diff] [blame]5384 defaults to using C calling conventions. The calling convention of the
5385 call must match the calling convention of the target function, or else the
5386 behavior is undefined.</li>
Devang Patel7e9b05e2008-10-06 18:50:38 +0000[diff] [blame]5387
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5388 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
5389 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
5390 '<tt>inreg</tt>' attributes are valid here.</li>
5391
5392 <li>'<tt>ty</tt>': the type of the call instruction itself which is also the
5393 type of the return value. Functions that return no value are marked
5394 <tt><a href="#t_void">void</a></tt>.</li>
5395
5396 <li>'<tt>fnty</tt>': shall be the signature of the pointer to function value
5397 being invoked. The argument types must match the types implied by this
5398 signature. This type can be omitted if the function is not varargs and if
5399 the function type does not return a pointer to a function.</li>
5400
5401 <li>'<tt>fnptrval</tt>': An LLVM value containing a pointer to a function to
5402 be invoked. In most cases, this is a direct function invocation, but
5403 indirect <tt>call</tt>s are just as possible, calling an arbitrary pointer
5404 to function value.</li>
5405
5406 <li>'<tt>function args</tt>': argument list whose types match the function
Chris Lattner47f2a832010-03-02 06:36:51 +0000[diff] [blame]5407 signature argument types and parameter attributes. All arguments must be
5408 of <a href="#t_firstclass">first class</a> type. If the function
5409 signature indicates the function accepts a variable number of arguments,
5410 the extra arguments can be specified.</li>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5411
5412 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
5413 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
5414 '<tt>readnone</tt>' attributes are valid here.</li>
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]5415</ol>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5416
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]5417<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5418<p>The '<tt>call</tt>' instruction is used to cause control flow to transfer to
5419 a specified function, with its incoming arguments bound to the specified
5420 values. Upon a '<tt><a href="#i_ret">ret</a></tt>' instruction in the called
5421 function, control flow continues with the instruction after the function
5422 call, and the return value of the function is bound to the result
5423 argument.</p>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5424
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]5425<h5>Example:</h5>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5426<pre>
Nick Lewyckya9b13d52007-09-08 13:57:50 +0000[diff] [blame]5427 %retval = call i32 @test(i32 %argc)
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]5428 call i32 (i8*, ...)* @printf(i8* %msg, i32 12, i8 42) <i>; yields i32</i>
Chris Lattnerfb7c88d2008-03-21 17:24:17 +0000[diff] [blame]5429 %X = tail call i32 @foo() <i>; yields i32</i>
5430 %Y = tail call <a href="#callingconv">fastcc</a> i32 @foo() <i>; yields i32</i>
5431 call void %foo(i8 97 signext)
Devang Pateld6cff512008-03-10 20:49:15 +0000[diff] [blame]5432
5433 %struct.A = type { i32, i8 }
Devang Patel7e9b05e2008-10-06 18:50:38 +0000[diff] [blame]5434 %r = call %struct.A @foo() <i>; yields { 32, i8 }</i>
Dan Gohmancc3132e2008-10-04 19:00:07 +0000[diff] [blame]5435 %gr = extractvalue %struct.A %r, 0 <i>; yields i32</i>
5436 %gr1 = extractvalue %struct.A %r, 1 <i>; yields i8</i>
Chris Lattner6cbe8e92008-10-08 06:26:11 +0000[diff] [blame]5437 %Z = call void @foo() noreturn <i>; indicates that %foo never returns normally</i>
Matthijs Kooijmaneefa7df2008-10-07 10:03:45 +0000[diff] [blame]5438 %ZZ = call zeroext i32 @bar() <i>; Return value is %zero extended</i>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5439</pre>
5440
Dale Johannesen68f971b2009-09-24 18:38:21 +0000[diff] [blame]5441<p>llvm treats calls to some functions with names and arguments that match the
Dale Johannesen722212d2009-09-25 17:04:42 +0000[diff] [blame]5442standard C99 library as being the C99 library functions, and may perform
5443optimizations or generate code for them under that assumption. This is
5444something we'd like to change in the future to provide better support for
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]5445freestanding environments and non-C-based languages.</p>
Dale Johannesen68f971b2009-09-24 18:38:21 +0000[diff] [blame]5446
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5447</div>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5448
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5449<!-- _______________________________________________________________________ -->
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5450<div class="doc_subsubsection">
Chris Lattner33337472006-01-13 23:26:01 +0000[diff] [blame]5451 <a name="i_va_arg">'<tt>va_arg</tt>' Instruction</a>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5452</div>
5453
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5454<div class="doc_text">
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5455
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]5456<h5>Syntax:</h5>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5457<pre>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]5458 &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]5459</pre>
5460
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]5461<h5>Overview:</h5>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]5462<p>The '<tt>va_arg</tt>' instruction is used to access arguments passed through
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5463 the "variable argument" area of a function call. It is used to implement the
5464 <tt>va_arg</tt> macro in C.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5465
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]5466<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5467<p>This instruction takes a <tt>va_list*</tt> value and the type of the
5468 argument. It returns a value of the specified argument type and increments
5469 the <tt>va_list</tt> to point to the next argument. The actual type
5470 of <tt>va_list</tt> is target specific.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5471
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]5472<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5473<p>The '<tt>va_arg</tt>' instruction loads an argument of the specified type
5474 from the specified <tt>va_list</tt> and causes the <tt>va_list</tt> to point
5475 to the next argument. For more information, see the variable argument
5476 handling <a href="#int_varargs">Intrinsic Functions</a>.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5477
5478<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]5479 take a variable number of arguments, for example, the <tt>vfprintf</tt>
5480 function.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5481
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5482<p><tt>va_arg</tt> is an LLVM instruction instead of
5483 an <a href="#intrinsics">intrinsic function</a> because it takes a type as an
5484 argument.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5485
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]5486<h5>Example:</h5>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5487<p>See the <a href="#int_varargs">variable argument processing</a> section.</p>
5488
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5489<p>Note that the code generator does not yet fully support va_arg on many
5490 targets. Also, it does not currently support va_arg with aggregate types on
5491 any target.</p>
Dan Gohman3065b612009-01-12 23:12:39 +0000[diff] [blame]5492
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5493</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5494
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5495<!-- *********************************************************************** -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]5496<div class="doc_section"> <a name="intrinsics">Intrinsic Functions</a> </div>
5497<!-- *********************************************************************** -->
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5498
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5499<div class="doc_text">
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5500
5501<p>LLVM supports the notion of an "intrinsic function". These functions have
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5502 well known names and semantics and are required to follow certain
5503 restrictions. Overall, these intrinsics represent an extension mechanism for
5504 the LLVM language that does not require changing all of the transformations
5505 in LLVM when adding to the language (or the bitcode reader/writer, the
5506 parser, etc...).</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5507
John Criswell88190562005-05-16 16:17:45 +0000[diff] [blame]5508<p>Intrinsic function names must all start with an "<tt>llvm.</tt>" prefix. This
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5509 prefix is reserved in LLVM for intrinsic names; thus, function names may not
5510 begin with this prefix. Intrinsic functions must always be external
5511 functions: you cannot define the body of intrinsic functions. Intrinsic
5512 functions may only be used in call or invoke instructions: it is illegal to
5513 take the address of an intrinsic function. Additionally, because intrinsic
5514 functions are part of the LLVM language, it is required if any are added that
5515 they be documented here.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5516
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5517<p>Some intrinsic functions can be overloaded, i.e., the intrinsic represents a
5518 family of functions that perform the same operation but on different data
5519 types. Because LLVM can represent over 8 million different integer types,
5520 overloading is used commonly to allow an intrinsic function to operate on any
5521 integer type. One or more of the argument types or the result type can be
5522 overloaded to accept any integer type. Argument types may also be defined as
5523 exactly matching a previous argument's type or the result type. This allows
5524 an intrinsic function which accepts multiple arguments, but needs all of them
5525 to be of the same type, to only be overloaded with respect to a single
5526 argument or the result.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5527
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5528<p>Overloaded intrinsics will have the names of its overloaded argument types
5529 encoded into its function name, each preceded by a period. Only those types
5530 which are overloaded result in a name suffix. Arguments whose type is matched
5531 against another type do not. For example, the <tt>llvm.ctpop</tt> function
5532 can take an integer of any width and returns an integer of exactly the same
5533 integer width. This leads to a family of functions such as
5534 <tt>i8 @llvm.ctpop.i8(i8 %val)</tt> and <tt>i29 @llvm.ctpop.i29(i29
5535 %val)</tt>. Only one type, the return type, is overloaded, and only one type
5536 suffix is required. Because the argument's type is matched against the return
5537 type, it does not require its own name suffix.</p>
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]5538
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5539<p>To learn how to add an intrinsic function, please see the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5540 <a href="ExtendingLLVM.html">Extending LLVM Guide</a>.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5541
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5542</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5543
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5544<!-- ======================================================================= -->
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5545<div class="doc_subsection">
5546 <a name="int_varargs">Variable Argument Handling Intrinsics</a>
5547</div>
5548
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5549<div class="doc_text">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5550
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5551<p>Variable argument support is defined in LLVM with
5552 the <a href="#i_va_arg"><tt>va_arg</tt></a> instruction and these three
5553 intrinsic functions. These functions are related to the similarly named
5554 macros defined in the <tt>&lt;stdarg.h&gt;</tt> header file.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5555
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5556<p>All of these functions operate on arguments that use a target-specific value
5557 type "<tt>va_list</tt>". The LLVM assembly language reference manual does
5558 not define what this type is, so all transformations should be prepared to
5559 handle these functions regardless of the type used.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5560
Chris Lattner30b868d2006-05-15 17:26:46 +0000[diff] [blame]5561<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]5562 instruction and the variable argument handling intrinsic functions are
5563 used.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5564
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]5565<div class="doc_code">
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5566<pre>
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]5567define i32 @test(i32 %X, ...) {
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5568 ; Initialize variable argument processing
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5569 %ap = alloca i8*
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]5570 %ap2 = bitcast i8** %ap to i8*
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]5571 call void @llvm.va_start(i8* %ap2)
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5572
5573 ; Read a single integer argument
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5574 %tmp = va_arg i8** %ap, i32
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5575
5576 ; Demonstrate usage of llvm.va_copy and llvm.va_end
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5577 %aq = alloca i8*
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]5578 %aq2 = bitcast i8** %aq to i8*
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5579 call void @llvm.va_copy(i8* %aq2, i8* %ap2)
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]5580 call void @llvm.va_end(i8* %aq2)
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5581
5582 ; Stop processing of arguments.
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]5583 call void @llvm.va_end(i8* %ap2)
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]5584 ret i32 %tmp
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5585}
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]5586
5587declare void @llvm.va_start(i8*)
5588declare void @llvm.va_copy(i8*, i8*)
5589declare void @llvm.va_end(i8*)
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5590</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5591</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5592
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]5593</div>
5594
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5595<!-- _______________________________________________________________________ -->
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5596<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5597 <a name="int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5598</div>
5599
5600
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5601<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5602
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5603<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5604<pre>
5605 declare void %llvm.va_start(i8* &lt;arglist&gt;)
5606</pre>
5607
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5608<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5609<p>The '<tt>llvm.va_start</tt>' intrinsic initializes <tt>*&lt;arglist&gt;</tt>
5610 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]5611
5612<h5>Arguments:</h5>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]5613<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]5614
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5615<h5>Semantics:</h5>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]5616<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]5617 macro available in C. In a target-dependent way, it initializes
5618 the <tt>va_list</tt> element to which the argument points, so that the next
5619 call to <tt>va_arg</tt> will produce the first variable argument passed to
5620 the function. Unlike the C <tt>va_start</tt> macro, this intrinsic does not
5621 need to know the last argument of the function as the compiler can figure
5622 that out.</p>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]5623
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5624</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5625
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5626<!-- _______________________________________________________________________ -->
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5627<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5628 <a name="int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5629</div>
5630
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5631<div class="doc_text">
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]5632
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5633<h5>Syntax:</h5>
5634<pre>
5635 declare void @llvm.va_end(i8* &lt;arglist&gt;)
5636</pre>
5637
5638<h5>Overview:</h5>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5639<p>The '<tt>llvm.va_end</tt>' intrinsic destroys <tt>*&lt;arglist&gt;</tt>,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5640 which has been initialized previously
5641 with <tt><a href="#int_va_start">llvm.va_start</a></tt>
5642 or <tt><a href="#i_va_copy">llvm.va_copy</a></tt>.</p>
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]5643
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5644<h5>Arguments:</h5>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5645<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]5646
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5647<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5648<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]5649 macro available in C. In a target-dependent way, it destroys
5650 the <tt>va_list</tt> element to which the argument points. Calls
5651 to <a href="#int_va_start"><tt>llvm.va_start</tt></a>
5652 and <a href="#int_va_copy"> <tt>llvm.va_copy</tt></a> must be matched exactly
5653 with calls to <tt>llvm.va_end</tt>.</p>
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]5654
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5655</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5656
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5657<!-- _______________________________________________________________________ -->
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5658<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5659 <a name="int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5660</div>
5661
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5662<div class="doc_text">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5663
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5664<h5>Syntax:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5665<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]5666 declare void @llvm.va_copy(i8* &lt;destarglist&gt;, i8* &lt;srcarglist&gt;)
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5667</pre>
5668
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5669<h5>Overview:</h5>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5670<p>The '<tt>llvm.va_copy</tt>' intrinsic copies the current argument position
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5671 from the source argument list to the destination argument list.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5672
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5673<h5>Arguments:</h5>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]5674<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]5675 The second argument is a pointer to a <tt>va_list</tt> element to copy
5676 from.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5677
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5678<h5>Semantics:</h5>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5679<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]5680 macro available in C. In a target-dependent way, it copies the
5681 source <tt>va_list</tt> element into the destination <tt>va_list</tt>
5682 element. This intrinsic is necessary because
5683 the <tt><a href="#int_va_start"> llvm.va_start</a></tt> intrinsic may be
5684 arbitrarily complex and require, for example, memory allocation.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5685
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5686</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5687
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5688<!-- ======================================================================= -->
5689<div class="doc_subsection">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5690 <a name="int_gc">Accurate Garbage Collection Intrinsics</a>
5691</div>
5692
5693<div class="doc_text">
5694
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5695<p>LLVM support for <a href="GarbageCollection.html">Accurate Garbage
Chris Lattner67c37d12008-08-05 18:29:16 +0000[diff] [blame]5696Collection</a> (GC) requires the implementation and generation of these
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5697intrinsics. These intrinsics allow identification of <a href="#int_gcroot">GC
5698roots on the stack</a>, as well as garbage collector implementations that
5699require <a href="#int_gcread">read</a> and <a href="#int_gcwrite">write</a>
5700barriers. Front-ends for type-safe garbage collected languages should generate
5701these intrinsics to make use of the LLVM garbage collectors. For more details,
5702see <a href="GarbageCollection.html">Accurate Garbage Collection with
5703LLVM</a>.</p>
Christopher Lamb55c6d4f2007-12-17 01:00:21 +0000[diff] [blame]5704
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5705<p>The garbage collection intrinsics only operate on objects in the generic
5706 address space (address space zero).</p>
Christopher Lamb55c6d4f2007-12-17 01:00:21 +0000[diff] [blame]5707
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5708</div>
5709
5710<!-- _______________________________________________________________________ -->
5711<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5712 <a name="int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5713</div>
5714
5715<div class="doc_text">
5716
5717<h5>Syntax:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5718<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]5719 declare void @llvm.gcroot(i8** %ptrloc, i8* %metadata)
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5720</pre>
5721
5722<h5>Overview:</h5>
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]5723<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]5724 the code generator, and allows some metadata to be associated with it.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5725
5726<h5>Arguments:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5727<p>The first argument specifies the address of a stack object that contains the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5728 root pointer. The second pointer (which must be either a constant or a
5729 global value address) contains the meta-data to be associated with the
5730 root.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5731
5732<h5>Semantics:</h5>
Chris Lattner851b7712008-04-24 05:59:56 +0000[diff] [blame]5733<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]5734 location. At compile-time, the code generator generates information to allow
5735 the runtime to find the pointer at GC safe points. The '<tt>llvm.gcroot</tt>'
5736 intrinsic may only be used in a function which <a href="#gc">specifies a GC
5737 algorithm</a>.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5738
5739</div>
5740
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5741<!-- _______________________________________________________________________ -->
5742<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5743 <a name="int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5744</div>
5745
5746<div class="doc_text">
5747
5748<h5>Syntax:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5749<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]5750 declare i8* @llvm.gcread(i8* %ObjPtr, i8** %Ptr)
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5751</pre>
5752
5753<h5>Overview:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5754<p>The '<tt>llvm.gcread</tt>' intrinsic identifies reads of references from heap
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5755 locations, allowing garbage collector implementations that require read
5756 barriers.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5757
5758<h5>Arguments:</h5>
Chris Lattnerf9228072006-03-14 20:02:51 +0000[diff] [blame]5759<p>The second argument is the address to read from, which should be an address
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5760 allocated from the garbage collector. The first object is a pointer to the
5761 start of the referenced object, if needed by the language runtime (otherwise
5762 null).</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5763
5764<h5>Semantics:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5765<p>The '<tt>llvm.gcread</tt>' intrinsic has the same semantics as a load
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5766 instruction, but may be replaced with substantially more complex code by the
5767 garbage collector runtime, as needed. The '<tt>llvm.gcread</tt>' intrinsic
5768 may only be used in a function which <a href="#gc">specifies a GC
5769 algorithm</a>.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5770
5771</div>
5772
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5773<!-- _______________________________________________________________________ -->
5774<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5775 <a name="int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5776</div>
5777
5778<div class="doc_text">
5779
5780<h5>Syntax:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5781<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]5782 declare void @llvm.gcwrite(i8* %P1, i8* %Obj, i8** %P2)
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5783</pre>
5784
5785<h5>Overview:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5786<p>The '<tt>llvm.gcwrite</tt>' intrinsic identifies writes of references to heap
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5787 locations, allowing garbage collector implementations that require write
5788 barriers (such as generational or reference counting collectors).</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5789
5790<h5>Arguments:</h5>
Chris Lattnerf9228072006-03-14 20:02:51 +0000[diff] [blame]5791<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]5792 object to store it to, and the third is the address of the field of Obj to
5793 store to. If the runtime does not require a pointer to the object, Obj may
5794 be null.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5795
5796<h5>Semantics:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5797<p>The '<tt>llvm.gcwrite</tt>' intrinsic has the same semantics as a store
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5798 instruction, but may be replaced with substantially more complex code by the
5799 garbage collector runtime, as needed. The '<tt>llvm.gcwrite</tt>' intrinsic
5800 may only be used in a function which <a href="#gc">specifies a GC
5801 algorithm</a>.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5802
5803</div>
5804
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5805<!-- ======================================================================= -->
5806<div class="doc_subsection">
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5807 <a name="int_codegen">Code Generator Intrinsics</a>
5808</div>
5809
5810<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5811
5812<p>These intrinsics are provided by LLVM to expose special features that may
5813 only be implemented with code generator support.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5814
5815</div>
5816
5817<!-- _______________________________________________________________________ -->
5818<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5819 <a name="int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5820</div>
5821
5822<div class="doc_text">
5823
5824<h5>Syntax:</h5>
5825<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]5826 declare i8 *@llvm.returnaddress(i32 &lt;level&gt;)
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5827</pre>
5828
5829<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5830<p>The '<tt>llvm.returnaddress</tt>' intrinsic attempts to compute a
5831 target-specific value indicating the return address of the current function
5832 or one of its callers.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5833
5834<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5835<p>The argument to this intrinsic indicates which function to return the address
5836 for. Zero indicates the calling function, one indicates its caller, etc.
5837 The argument is <b>required</b> to be a constant integer value.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5838
5839<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5840<p>The '<tt>llvm.returnaddress</tt>' intrinsic either returns a pointer
5841 indicating the return address of the specified call frame, or zero if it
5842 cannot be identified. The value returned by this intrinsic is likely to be
5843 incorrect or 0 for arguments other than zero, so it should only be used for
5844 debugging purposes.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5845
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5846<p>Note that calling this intrinsic does not prevent function inlining or other
5847 aggressive transformations, so the value returned may not be that of the
5848 obvious source-language caller.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5849
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5850</div>
5851
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5852<!-- _______________________________________________________________________ -->
5853<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5854 <a name="int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5855</div>
5856
5857<div class="doc_text">
5858
5859<h5>Syntax:</h5>
5860<pre>
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]5861 declare i8* @llvm.frameaddress(i32 &lt;level&gt;)
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5862</pre>
5863
5864<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5865<p>The '<tt>llvm.frameaddress</tt>' intrinsic attempts to return the
5866 target-specific frame pointer value for the specified stack frame.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5867
5868<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5869<p>The argument to this intrinsic indicates which function to return the frame
5870 pointer for. Zero indicates the calling function, one indicates its caller,
5871 etc. The argument is <b>required</b> to be a constant integer value.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5872
5873<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5874<p>The '<tt>llvm.frameaddress</tt>' intrinsic either returns a pointer
5875 indicating the frame address of the specified call frame, or zero if it
5876 cannot be identified. The value returned by this intrinsic is likely to be
5877 incorrect or 0 for arguments other than zero, so it should only be used for
5878 debugging purposes.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5879
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5880<p>Note that calling this intrinsic does not prevent function inlining or other
5881 aggressive transformations, so the value returned may not be that of the
5882 obvious source-language caller.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5883
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5884</div>
5885
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]5886<!-- _______________________________________________________________________ -->
5887<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5888 <a name="int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]5889</div>
5890
5891<div class="doc_text">
5892
5893<h5>Syntax:</h5>
5894<pre>
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]5895 declare i8* @llvm.stacksave()
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]5896</pre>
5897
5898<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5899<p>The '<tt>llvm.stacksave</tt>' intrinsic is used to remember the current state
5900 of the function stack, for use
5901 with <a href="#int_stackrestore"> <tt>llvm.stackrestore</tt></a>. This is
5902 useful for implementing language features like scoped automatic variable
5903 sized arrays in C99.</p>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]5904
5905<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5906<p>This intrinsic returns a opaque pointer value that can be passed
5907 to <a href="#int_stackrestore"><tt>llvm.stackrestore</tt></a>. When
5908 an <tt>llvm.stackrestore</tt> intrinsic is executed with a value saved
5909 from <tt>llvm.stacksave</tt>, it effectively restores the state of the stack
5910 to the state it was in when the <tt>llvm.stacksave</tt> intrinsic executed.
5911 In practice, this pops any <a href="#i_alloca">alloca</a> blocks from the
5912 stack that were allocated after the <tt>llvm.stacksave</tt> was executed.</p>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]5913
5914</div>
5915
5916<!-- _______________________________________________________________________ -->
5917<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5918 <a name="int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]5919</div>
5920
5921<div class="doc_text">
5922
5923<h5>Syntax:</h5>
5924<pre>
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]5925 declare void @llvm.stackrestore(i8* %ptr)
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]5926</pre>
5927
5928<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5929<p>The '<tt>llvm.stackrestore</tt>' intrinsic is used to restore the state of
5930 the function stack to the state it was in when the
5931 corresponding <a href="#int_stacksave"><tt>llvm.stacksave</tt></a> intrinsic
5932 executed. This is useful for implementing language features like scoped
5933 automatic variable sized arrays in C99.</p>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]5934
5935<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5936<p>See the description
5937 for <a href="#int_stacksave"><tt>llvm.stacksave</tt></a>.</p>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]5938
5939</div>
5940
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]5941<!-- _______________________________________________________________________ -->
5942<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5943 <a name="int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a>
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]5944</div>
5945
5946<div class="doc_text">
5947
5948<h5>Syntax:</h5>
5949<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]5950 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]5951</pre>
5952
5953<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5954<p>The '<tt>llvm.prefetch</tt>' intrinsic is a hint to the code generator to
5955 insert a prefetch instruction if supported; otherwise, it is a noop.
5956 Prefetches have no effect on the behavior of the program but can change its
5957 performance characteristics.</p>
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]5958
5959<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5960<p><tt>address</tt> is the address to be prefetched, <tt>rw</tt> is the
5961 specifier determining if the fetch should be for a read (0) or write (1),
5962 and <tt>locality</tt> is a temporal locality specifier ranging from (0) - no
5963 locality, to (3) - extremely local keep in cache. The <tt>rw</tt>
5964 and <tt>locality</tt> arguments must be constant integers.</p>
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]5965
5966<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5967<p>This intrinsic does not modify the behavior of the program. In particular,
5968 prefetches cannot trap and do not produce a value. On targets that support
5969 this intrinsic, the prefetch can provide hints to the processor cache for
5970 better performance.</p>
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]5971
5972</div>
5973
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]5974<!-- _______________________________________________________________________ -->
5975<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5976 <a name="int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a>
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]5977</div>
5978
5979<div class="doc_text">
5980
5981<h5>Syntax:</h5>
5982<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]5983 declare void @llvm.pcmarker(i32 &lt;id&gt;)
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]5984</pre>
5985
5986<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5987<p>The '<tt>llvm.pcmarker</tt>' intrinsic is a method to export a Program
5988 Counter (PC) in a region of code to simulators and other tools. The method
5989 is target specific, but it is expected that the marker will use exported
5990 symbols to transmit the PC of the marker. The marker makes no guarantees
5991 that it will remain with any specific instruction after optimizations. It is
5992 possible that the presence of a marker will inhibit optimizations. The
5993 intended use is to be inserted after optimizations to allow correlations of
5994 simulation runs.</p>
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]5995
5996<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5997<p><tt>id</tt> is a numerical id identifying the marker.</p>
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]5998
5999<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6000<p>This intrinsic does not modify the behavior of the program. Backends that do
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]6001 not support this intrinsic may ignore it.</p>
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]6002
6003</div>
6004
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]6005<!-- _______________________________________________________________________ -->
6006<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6007 <a name="int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a>
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]6008</div>
6009
6010<div class="doc_text">
6011
6012<h5>Syntax:</h5>
6013<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]6014 declare i64 @llvm.readcyclecounter()
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]6015</pre>
6016
6017<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6018<p>The '<tt>llvm.readcyclecounter</tt>' intrinsic provides access to the cycle
6019 counter register (or similar low latency, high accuracy clocks) on those
6020 targets that support it. On X86, it should map to RDTSC. On Alpha, it
6021 should map to RPCC. As the backing counters overflow quickly (on the order
6022 of 9 seconds on alpha), this should only be used for small timings.</p>
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]6023
6024<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6025<p>When directly supported, reading the cycle counter should not modify any
6026 memory. Implementations are allowed to either return a application specific
6027 value or a system wide value. On backends without support, this is lowered
6028 to a constant 0.</p>
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]6029
6030</div>
6031
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6032<!-- ======================================================================= -->
6033<div class="doc_subsection">
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6034 <a name="int_libc">Standard C Library Intrinsics</a>
6035</div>
6036
6037<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6038
6039<p>LLVM provides intrinsics for a few important standard C library functions.
6040 These intrinsics allow source-language front-ends to pass information about
6041 the alignment of the pointer arguments to the code generator, providing
6042 opportunity for more efficient code generation.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6043
6044</div>
6045
6046<!-- _______________________________________________________________________ -->
6047<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6048 <a name="int_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6049</div>
6050
6051<div class="doc_text">
6052
6053<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6054<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]6055 integer bit width and for different address spaces. Not all targets support
6056 all bit widths however.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6057
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6058<pre>
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]6059 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]6060 i32 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]6061 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]6062 i64 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6063</pre>
6064
6065<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6066<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
6067 source location to the destination location.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6068
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6069<p>Note that, unlike the standard libc function, the <tt>llvm.memcpy.*</tt>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6070 intrinsics do not return a value, takes extra alignment/isvolatile arguments
6071 and the pointers can be in specified address spaces.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6072
6073<h5>Arguments:</h5>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6074
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6075<p>The first argument is a pointer to the destination, the second is a pointer
6076 to the source. The third argument is an integer argument specifying the
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6077 number of bytes to copy, the fourth argument is the alignment of the
6078 source and destination locations, and the fifth is a boolean indicating a
6079 volatile access.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6080
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]6081<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]6082 then the caller guarantees that both the source and destination pointers are
6083 aligned to that boundary.</p>
Chris Lattner4c67c482004-02-12 21:18:15 +0000[diff] [blame]6084
Jeffrey Yasskin5d284ae2010-04-26 21:21:24 +0000[diff] [blame]6085<p>If the <tt>isvolatile</tt> parameter is <tt>true</tt>, the
6086 <tt>llvm.memcpy</tt> call is a <a href="#volatile">volatile operation</a>.
6087 The detailed access behavior is not very cleanly specified and it is unwise
6088 to depend on it.</p>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6089
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6090<h5>Semantics:</h5>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6091
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6092<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
6093 source location to the destination location, which are not allowed to
6094 overlap. It copies "len" bytes of memory over. If the argument is known to
6095 be aligned to some boundary, this can be specified as the fourth argument,
6096 otherwise it should be set to 0 or 1.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6097
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6098</div>
6099
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6100<!-- _______________________________________________________________________ -->
6101<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6102 <a name="int_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a>
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6103</div>
6104
6105<div class="doc_text">
6106
6107<h5>Syntax:</h5>
Chris Lattnerdd708342008-11-21 16:42:48 +0000[diff] [blame]6108<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]6109 width and for different address space. Not all targets support all bit
6110 widths however.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6111
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6112<pre>
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]6113 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]6114 i32 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]6115 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]6116 i64 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6117</pre>
6118
6119<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6120<p>The '<tt>llvm.memmove.*</tt>' intrinsics move a block of memory from the
6121 source location to the destination location. It is similar to the
6122 '<tt>llvm.memcpy</tt>' intrinsic but allows the two memory locations to
6123 overlap.</p>
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6124
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6125<p>Note that, unlike the standard libc function, the <tt>llvm.memmove.*</tt>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6126 intrinsics do not return a value, takes extra alignment/isvolatile arguments
6127 and the pointers can be in specified address spaces.</p>
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6128
6129<h5>Arguments:</h5>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6130
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6131<p>The first argument is a pointer to the destination, the second is a pointer
6132 to the source. The third argument is an integer argument specifying the
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6133 number of bytes to copy, the fourth argument is the alignment of the
6134 source and destination locations, and the fifth is a boolean indicating a
6135 volatile access.</p>
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6136
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]6137<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]6138 then the caller guarantees that the source and destination pointers are
6139 aligned to that boundary.</p>
Chris Lattner4c67c482004-02-12 21:18:15 +0000[diff] [blame]6140
Jeffrey Yasskin5d284ae2010-04-26 21:21:24 +0000[diff] [blame]6141<p>If the <tt>isvolatile</tt> parameter is <tt>true</tt>, the
6142 <tt>llvm.memmove</tt> call is a <a href="#volatile">volatile operation</a>.
6143 The detailed access behavior is not very cleanly specified and it is unwise
6144 to depend on it.</p>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6145
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6146<h5>Semantics:</h5>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6147
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6148<p>The '<tt>llvm.memmove.*</tt>' intrinsics copy a block of memory from the
6149 source location to the destination location, which may overlap. It copies
6150 "len" bytes of memory over. If the argument is known to be aligned to some
6151 boundary, this can be specified as the fourth argument, otherwise it should
6152 be set to 0 or 1.</p>
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6153
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6154</div>
6155
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6156<!-- _______________________________________________________________________ -->
6157<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6158 <a name="int_memset">'<tt>llvm.memset.*</tt>' Intrinsics</a>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6159</div>
6160
6161<div class="doc_text">
6162
6163<h5>Syntax:</h5>
Chris Lattnerdd708342008-11-21 16:42:48 +0000[diff] [blame]6164<p>This is an overloaded intrinsic. You can use llvm.memset on any integer bit
Mon P Wang508127b2010-04-07 06:35:53 +0000[diff] [blame]6165 width and for different address spaces. Not all targets support all bit
6166 widths however.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6167
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6168<pre>
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]6169 declare void @llvm.memset.p0i8.i32(i8* &lt;dest&gt;, i8 &lt;val&gt;,
Chris Lattner685db9d2010-04-08 00:54:34 +0000[diff] [blame]6170 i32 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]6171 declare void @llvm.memset.p0i8.i64(i8* &lt;dest&gt;, i8 &lt;val&gt;,
Chris Lattner685db9d2010-04-08 00:54:34 +0000[diff] [blame]6172 i64 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6173</pre>
6174
6175<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6176<p>The '<tt>llvm.memset.*</tt>' intrinsics fill a block of memory with a
6177 particular byte value.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6178
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6179<p>Note that, unlike the standard libc function, the <tt>llvm.memset</tt>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6180 intrinsic does not return a value, takes extra alignment/volatile arguments,
6181 and the destination can be in an arbitrary address space.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6182
6183<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6184<p>The first argument is a pointer to the destination to fill, the second is the
6185 byte value to fill it with, the third argument is an integer argument
6186 specifying the number of bytes to fill, and the fourth argument is the known
6187 alignment of destination location.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6188
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]6189<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]6190 then the caller guarantees that the destination pointer is aligned to that
6191 boundary.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6192
Jeffrey Yasskin5d284ae2010-04-26 21:21:24 +0000[diff] [blame]6193<p>If the <tt>isvolatile</tt> parameter is <tt>true</tt>, the
6194 <tt>llvm.memset</tt> call is a <a href="#volatile">volatile operation</a>.
6195 The detailed access behavior is not very cleanly specified and it is unwise
6196 to depend on it.</p>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6197
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6198<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6199<p>The '<tt>llvm.memset.*</tt>' intrinsics fill "len" bytes of memory starting
6200 at the destination location. If the argument is known to be aligned to some
6201 boundary, this can be specified as the fourth argument, otherwise it should
6202 be set to 0 or 1.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6203
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6204</div>
6205
Chris Lattner3b4f4372004-06-11 02:28:03 +0000[diff] [blame]6206<!-- _______________________________________________________________________ -->
6207<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6208 <a name="int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a>
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]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.sqrt</tt> on any
6215 floating point or vector of floating point type. Not all targets support all
6216 types however.</p>
6217
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]6218<pre>
Dale Johannesendd89d272007-10-02 17:47:38 +0000[diff] [blame]6219 declare float @llvm.sqrt.f32(float %Val)
6220 declare double @llvm.sqrt.f64(double %Val)
6221 declare x86_fp80 @llvm.sqrt.f80(x86_fp80 %Val)
6222 declare fp128 @llvm.sqrt.f128(fp128 %Val)
6223 declare ppc_fp128 @llvm.sqrt.ppcf128(ppc_fp128 %Val)
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]6224</pre>
6225
6226<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6227<p>The '<tt>llvm.sqrt</tt>' intrinsics return the sqrt of the specified operand,
6228 returning the same value as the libm '<tt>sqrt</tt>' functions would.
6229 Unlike <tt>sqrt</tt> in libm, however, <tt>llvm.sqrt</tt> has undefined
6230 behavior for negative numbers other than -0.0 (which allows for better
6231 optimization, because there is no need to worry about errno being
6232 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]6233
6234<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6235<p>The argument and return value are floating point numbers of the same
6236 type.</p>
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]6237
6238<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6239<p>This function returns the sqrt of the specified operand if it is a
6240 nonnegative floating point number.</p>
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]6241
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]6242</div>
6243
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]6244<!-- _______________________________________________________________________ -->
6245<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6246 <a name="int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a>
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]6247</div>
6248
6249<div class="doc_text">
6250
6251<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6252<p>This is an overloaded intrinsic. You can use <tt>llvm.powi</tt> on any
6253 floating point or vector of floating point type. Not all targets support all
6254 types however.</p>
6255
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]6256<pre>
Dale Johannesendd89d272007-10-02 17:47:38 +0000[diff] [blame]6257 declare float @llvm.powi.f32(float %Val, i32 %power)
6258 declare double @llvm.powi.f64(double %Val, i32 %power)
6259 declare x86_fp80 @llvm.powi.f80(x86_fp80 %Val, i32 %power)
6260 declare fp128 @llvm.powi.f128(fp128 %Val, i32 %power)
6261 declare ppc_fp128 @llvm.powi.ppcf128(ppc_fp128 %Val, i32 %power)
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]6262</pre>
6263
6264<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6265<p>The '<tt>llvm.powi.*</tt>' intrinsics return the first operand raised to the
6266 specified (positive or negative) power. The order of evaluation of
6267 multiplications is not defined. When a vector of floating point type is
6268 used, the second argument remains a scalar integer value.</p>
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]6269
6270<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6271<p>The second argument is an integer power, and the first is a value to raise to
6272 that power.</p>
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]6273
6274<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6275<p>This function returns the first value raised to the second power with an
6276 unspecified sequence of rounding operations.</p>
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]6277
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]6278</div>
6279
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6280<!-- _______________________________________________________________________ -->
6281<div class="doc_subsubsection">
6282 <a name="int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a>
6283</div>
6284
6285<div class="doc_text">
6286
6287<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6288<p>This is an overloaded intrinsic. You can use <tt>llvm.sin</tt> on any
6289 floating point or vector of floating point type. Not all targets support all
6290 types however.</p>
6291
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6292<pre>
6293 declare float @llvm.sin.f32(float %Val)
6294 declare double @llvm.sin.f64(double %Val)
6295 declare x86_fp80 @llvm.sin.f80(x86_fp80 %Val)
6296 declare fp128 @llvm.sin.f128(fp128 %Val)
6297 declare ppc_fp128 @llvm.sin.ppcf128(ppc_fp128 %Val)
6298</pre>
6299
6300<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6301<p>The '<tt>llvm.sin.*</tt>' intrinsics return the sine of the operand.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6302
6303<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6304<p>The argument and return value are floating point numbers of the same
6305 type.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6306
6307<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6308<p>This function returns the sine of the specified operand, returning the same
6309 values as the libm <tt>sin</tt> functions would, and handles error conditions
6310 in the same way.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6311
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6312</div>
6313
6314<!-- _______________________________________________________________________ -->
6315<div class="doc_subsubsection">
6316 <a name="int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a>
6317</div>
6318
6319<div class="doc_text">
6320
6321<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6322<p>This is an overloaded intrinsic. You can use <tt>llvm.cos</tt> on any
6323 floating point or vector of floating point type. Not all targets support all
6324 types however.</p>
6325
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6326<pre>
6327 declare float @llvm.cos.f32(float %Val)
6328 declare double @llvm.cos.f64(double %Val)
6329 declare x86_fp80 @llvm.cos.f80(x86_fp80 %Val)
6330 declare fp128 @llvm.cos.f128(fp128 %Val)
6331 declare ppc_fp128 @llvm.cos.ppcf128(ppc_fp128 %Val)
6332</pre>
6333
6334<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6335<p>The '<tt>llvm.cos.*</tt>' intrinsics return the cosine of the operand.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6336
6337<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6338<p>The argument and return value are floating point numbers of the same
6339 type.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6340
6341<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6342<p>This function returns the cosine of the specified operand, returning the same
6343 values as the libm <tt>cos</tt> functions would, and handles error conditions
6344 in the same way.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6345
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6346</div>
6347
6348<!-- _______________________________________________________________________ -->
6349<div class="doc_subsubsection">
6350 <a name="int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a>
6351</div>
6352
6353<div class="doc_text">
6354
6355<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6356<p>This is an overloaded intrinsic. You can use <tt>llvm.pow</tt> on any
6357 floating point or vector of floating point type. Not all targets support all
6358 types however.</p>
6359
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6360<pre>
6361 declare float @llvm.pow.f32(float %Val, float %Power)
6362 declare double @llvm.pow.f64(double %Val, double %Power)
6363 declare x86_fp80 @llvm.pow.f80(x86_fp80 %Val, x86_fp80 %Power)
6364 declare fp128 @llvm.pow.f128(fp128 %Val, fp128 %Power)
6365 declare ppc_fp128 @llvm.pow.ppcf128(ppc_fp128 %Val, ppc_fp128 Power)
6366</pre>
6367
6368<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6369<p>The '<tt>llvm.pow.*</tt>' intrinsics return the first operand raised to the
6370 specified (positive or negative) power.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6371
6372<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6373<p>The second argument is a floating point power, and the first is a value to
6374 raise to that power.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6375
6376<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6377<p>This function returns the first value raised to the second power, returning
6378 the same values as the libm <tt>pow</tt> functions would, and handles error
6379 conditions in the same way.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6380
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6381</div>
6382
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6383<!-- ======================================================================= -->
6384<div class="doc_subsection">
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]6385 <a name="int_manip">Bit Manipulation Intrinsics</a>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6386</div>
6387
6388<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6389
6390<p>LLVM provides intrinsics for a few important bit manipulation operations.
6391 These allow efficient code generation for some algorithms.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6392
6393</div>
6394
6395<!-- _______________________________________________________________________ -->
6396<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6397 <a name="int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a>
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]6398</div>
6399
6400<div class="doc_text">
6401
6402<h5>Syntax:</h5>
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]6403<p>This is an overloaded intrinsic function. You can use bswap on any integer
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6404 type that is an even number of bytes (i.e. BitWidth % 16 == 0).</p>
6405
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]6406<pre>
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]6407 declare i16 @llvm.bswap.i16(i16 &lt;id&gt;)
6408 declare i32 @llvm.bswap.i32(i32 &lt;id&gt;)
6409 declare i64 @llvm.bswap.i64(i64 &lt;id&gt;)
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]6410</pre>
6411
6412<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6413<p>The '<tt>llvm.bswap</tt>' family of intrinsics is used to byte swap integer
6414 values with an even number of bytes (positive multiple of 16 bits). These
6415 are useful for performing operations on data that is not in the target's
6416 native byte order.</p>
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]6417
6418<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6419<p>The <tt>llvm.bswap.i16</tt> intrinsic returns an i16 value that has the high
6420 and low byte of the input i16 swapped. Similarly,
6421 the <tt>llvm.bswap.i32</tt> intrinsic returns an i32 value that has the four
6422 bytes of the input i32 swapped, so that if the input bytes are numbered 0, 1,
6423 2, 3 then the returned i32 will have its bytes in 3, 2, 1, 0 order.
6424 The <tt>llvm.bswap.i48</tt>, <tt>llvm.bswap.i64</tt> and other intrinsics
6425 extend this concept to additional even-byte lengths (6 bytes, 8 bytes and
6426 more, respectively).</p>
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]6427
6428</div>
6429
6430<!-- _______________________________________________________________________ -->
6431<div class="doc_subsubsection">
Reid Spencerb4f9a6f2006-01-16 21:12:35 +0000[diff] [blame]6432 <a name="int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic</a>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6433</div>
6434
6435<div class="doc_text">
6436
6437<h5>Syntax:</h5>
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]6438<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]6439 width. Not all targets support all bit widths however.</p>
6440
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6441<pre>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6442 declare i8 @llvm.ctpop.i8(i8 &lt;src&gt;)
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]6443 declare i16 @llvm.ctpop.i16(i16 &lt;src&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]6444 declare i32 @llvm.ctpop.i32(i32 &lt;src&gt;)
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]6445 declare i64 @llvm.ctpop.i64(i64 &lt;src&gt;)
6446 declare i256 @llvm.ctpop.i256(i256 &lt;src&gt;)
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6447</pre>
6448
6449<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6450<p>The '<tt>llvm.ctpop</tt>' family of intrinsics counts the number of bits set
6451 in a value.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6452
6453<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6454<p>The only argument is the value to be counted. The argument may be of any
6455 integer type. The return type must match the argument type.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6456
6457<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6458<p>The '<tt>llvm.ctpop</tt>' intrinsic counts the 1's in a variable.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6459
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6460</div>
6461
6462<!-- _______________________________________________________________________ -->
6463<div class="doc_subsubsection">
Chris Lattnerb748c672006-01-16 22:34:14 +0000[diff] [blame]6464 <a name="int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic</a>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6465</div>
6466
6467<div class="doc_text">
6468
6469<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6470<p>This is an overloaded intrinsic. You can use <tt>llvm.ctlz</tt> on any
6471 integer bit width. Not all targets support all bit widths however.</p>
6472
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6473<pre>
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]6474 declare i8 @llvm.ctlz.i8 (i8 &lt;src&gt;)
6475 declare i16 @llvm.ctlz.i16(i16 &lt;src&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]6476 declare i32 @llvm.ctlz.i32(i32 &lt;src&gt;)
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]6477 declare i64 @llvm.ctlz.i64(i64 &lt;src&gt;)
6478 declare i256 @llvm.ctlz.i256(i256 &lt;src&gt;)
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6479</pre>
6480
6481<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6482<p>The '<tt>llvm.ctlz</tt>' family of intrinsic functions counts the number of
6483 leading zeros in a variable.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6484
6485<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6486<p>The only argument is the value to be counted. The argument may be of any
6487 integer type. The return type must match the argument type.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6488
6489<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6490<p>The '<tt>llvm.ctlz</tt>' intrinsic counts the leading (most significant)
6491 zeros in a variable. If the src == 0 then the result is the size in bits of
6492 the type of src. For example, <tt>llvm.ctlz(i32 2) = 30</tt>.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6493
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6494</div>
Chris Lattner3b4f4372004-06-11 02:28:03 +0000[diff] [blame]6495
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]6496<!-- _______________________________________________________________________ -->
6497<div class="doc_subsubsection">
Chris Lattnerb748c672006-01-16 22:34:14 +0000[diff] [blame]6498 <a name="int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic</a>
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]6499</div>
6500
6501<div class="doc_text">
6502
6503<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6504<p>This is an overloaded intrinsic. You can use <tt>llvm.cttz</tt> on any
6505 integer bit width. Not all targets support all bit widths however.</p>
6506
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]6507<pre>
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]6508 declare i8 @llvm.cttz.i8 (i8 &lt;src&gt;)
6509 declare i16 @llvm.cttz.i16(i16 &lt;src&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]6510 declare i32 @llvm.cttz.i32(i32 &lt;src&gt;)
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]6511 declare i64 @llvm.cttz.i64(i64 &lt;src&gt;)
6512 declare i256 @llvm.cttz.i256(i256 &lt;src&gt;)
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]6513</pre>
6514
6515<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6516<p>The '<tt>llvm.cttz</tt>' family of intrinsic functions counts the number of
6517 trailing zeros.</p>
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]6518
6519<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6520<p>The only argument is the value to be counted. The argument may be of any
6521 integer type. The return type must match the argument type.</p>
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]6522
6523<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6524<p>The '<tt>llvm.cttz</tt>' intrinsic counts the trailing (least significant)
6525 zeros in a variable. If the src == 0 then the result is the size in bits of
6526 the type of src. For example, <tt>llvm.cttz(2) = 1</tt>.</p>
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]6527
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]6528</div>
6529
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]6530<!-- ======================================================================= -->
6531<div class="doc_subsection">
6532 <a name="int_overflow">Arithmetic with Overflow Intrinsics</a>
6533</div>
6534
6535<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6536
6537<p>LLVM provides intrinsics for some arithmetic with overflow operations.</p>
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]6538
6539</div>
6540
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6541<!-- _______________________________________________________________________ -->
6542<div class="doc_subsubsection">
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]6543 <a name="int_sadd_overflow">'<tt>llvm.sadd.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6544</div>
6545
6546<div class="doc_text">
6547
6548<h5>Syntax:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6549<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]6550 on any integer bit width.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6551
6552<pre>
6553 declare {i16, i1} @llvm.sadd.with.overflow.i16(i16 %a, i16 %b)
6554 declare {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
6555 declare {i64, i1} @llvm.sadd.with.overflow.i64(i64 %a, i64 %b)
6556</pre>
6557
6558<h5>Overview:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6559<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6560 a signed addition of the two arguments, and indicate whether an overflow
6561 occurred during the signed summation.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6562
6563<h5>Arguments:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6564<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]6565 be of integer types of any bit width, but they must have the same bit
6566 width. The second element of the result structure must be of
6567 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6568 undergo signed addition.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6569
6570<h5>Semantics:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6571<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6572 a signed addition of the two variables. They return a structure &mdash; the
6573 first element of which is the signed summation, and the second element of
6574 which is a bit specifying if the signed summation resulted in an
6575 overflow.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6576
6577<h5>Examples:</h5>
6578<pre>
6579 %res = call {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
6580 %sum = extractvalue {i32, i1} %res, 0
6581 %obit = extractvalue {i32, i1} %res, 1
6582 br i1 %obit, label %overflow, label %normal
6583</pre>
6584
6585</div>
6586
6587<!-- _______________________________________________________________________ -->
6588<div class="doc_subsubsection">
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]6589 <a name="int_uadd_overflow">'<tt>llvm.uadd.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6590</div>
6591
6592<div class="doc_text">
6593
6594<h5>Syntax:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6595<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]6596 on any integer bit width.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6597
6598<pre>
6599 declare {i16, i1} @llvm.uadd.with.overflow.i16(i16 %a, i16 %b)
6600 declare {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
6601 declare {i64, i1} @llvm.uadd.with.overflow.i64(i64 %a, i64 %b)
6602</pre>
6603
6604<h5>Overview:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6605<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6606 an unsigned addition of the two arguments, and indicate whether a carry
6607 occurred during the unsigned summation.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6608
6609<h5>Arguments:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6610<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]6611 be of integer types of any bit width, but they must have the same bit
6612 width. The second element of the result structure must be of
6613 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6614 undergo unsigned addition.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6615
6616<h5>Semantics:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6617<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6618 an unsigned addition of the two arguments. They return a structure &mdash;
6619 the first element of which is the sum, and the second element of which is a
6620 bit specifying if the unsigned summation resulted in a carry.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6621
6622<h5>Examples:</h5>
6623<pre>
6624 %res = call {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
6625 %sum = extractvalue {i32, i1} %res, 0
6626 %obit = extractvalue {i32, i1} %res, 1
6627 br i1 %obit, label %carry, label %normal
6628</pre>
6629
6630</div>
6631
6632<!-- _______________________________________________________________________ -->
6633<div class="doc_subsubsection">
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]6634 <a name="int_ssub_overflow">'<tt>llvm.ssub.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6635</div>
6636
6637<div class="doc_text">
6638
6639<h5>Syntax:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6640<p>This is an overloaded intrinsic. You can use <tt>llvm.ssub.with.overflow</tt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6641 on any integer bit width.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6642
6643<pre>
6644 declare {i16, i1} @llvm.ssub.with.overflow.i16(i16 %a, i16 %b)
6645 declare {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
6646 declare {i64, i1} @llvm.ssub.with.overflow.i64(i64 %a, i64 %b)
6647</pre>
6648
6649<h5>Overview:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6650<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6651 a signed subtraction of the two arguments, and indicate whether an overflow
6652 occurred during the signed subtraction.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6653
6654<h5>Arguments:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6655<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]6656 be of integer types of any bit width, but they must have the same bit
6657 width. The second element of the result structure must be of
6658 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6659 undergo signed subtraction.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6660
6661<h5>Semantics:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6662<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6663 a signed subtraction of the two arguments. They return a structure &mdash;
6664 the first element of which is the subtraction, and the second element of
6665 which is a bit specifying if the signed subtraction resulted in an
6666 overflow.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6667
6668<h5>Examples:</h5>
6669<pre>
6670 %res = call {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
6671 %sum = extractvalue {i32, i1} %res, 0
6672 %obit = extractvalue {i32, i1} %res, 1
6673 br i1 %obit, label %overflow, label %normal
6674</pre>
6675
6676</div>
6677
6678<!-- _______________________________________________________________________ -->
6679<div class="doc_subsubsection">
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]6680 <a name="int_usub_overflow">'<tt>llvm.usub.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6681</div>
6682
6683<div class="doc_text">
6684
6685<h5>Syntax:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6686<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]6687 on any integer bit width.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6688
6689<pre>
6690 declare {i16, i1} @llvm.usub.with.overflow.i16(i16 %a, i16 %b)
6691 declare {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
6692 declare {i64, i1} @llvm.usub.with.overflow.i64(i64 %a, i64 %b)
6693</pre>
6694
6695<h5>Overview:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6696<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6697 an unsigned subtraction of the two arguments, and indicate whether an
6698 overflow occurred during the unsigned subtraction.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6699
6700<h5>Arguments:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6701<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]6702 be of integer types of any bit width, but they must have the same bit
6703 width. The second element of the result structure must be of
6704 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6705 undergo unsigned subtraction.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6706
6707<h5>Semantics:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6708<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6709 an unsigned subtraction of the two arguments. They return a structure &mdash;
6710 the first element of which is the subtraction, and the second element of
6711 which is a bit specifying if the unsigned subtraction resulted in an
6712 overflow.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6713
6714<h5>Examples:</h5>
6715<pre>
6716 %res = call {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
6717 %sum = extractvalue {i32, i1} %res, 0
6718 %obit = extractvalue {i32, i1} %res, 1
6719 br i1 %obit, label %overflow, label %normal
6720</pre>
6721
6722</div>
6723
6724<!-- _______________________________________________________________________ -->
6725<div class="doc_subsubsection">
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]6726 <a name="int_smul_overflow">'<tt>llvm.smul.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6727</div>
6728
6729<div class="doc_text">
6730
6731<h5>Syntax:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6732<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]6733 on any integer bit width.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6734
6735<pre>
6736 declare {i16, i1} @llvm.smul.with.overflow.i16(i16 %a, i16 %b)
6737 declare {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
6738 declare {i64, i1} @llvm.smul.with.overflow.i64(i64 %a, i64 %b)
6739</pre>
6740
6741<h5>Overview:</h5>
6742
6743<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6744 a signed multiplication of the two arguments, and indicate whether an
6745 overflow occurred during the signed multiplication.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6746
6747<h5>Arguments:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6748<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]6749 be of integer types of any bit width, but they must have the same bit
6750 width. The second element of the result structure must be of
6751 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6752 undergo signed multiplication.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6753
6754<h5>Semantics:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6755<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6756 a signed multiplication of the two arguments. They return a structure &mdash;
6757 the first element of which is the multiplication, and the second element of
6758 which is a bit specifying if the signed multiplication resulted in an
6759 overflow.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6760
6761<h5>Examples:</h5>
6762<pre>
6763 %res = call {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
6764 %sum = extractvalue {i32, i1} %res, 0
6765 %obit = extractvalue {i32, i1} %res, 1
6766 br i1 %obit, label %overflow, label %normal
6767</pre>
6768
Reid Spencer5bf54c82007-04-11 23:23:49 +0000[diff] [blame]6769</div>
6770
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]6771<!-- _______________________________________________________________________ -->
6772<div class="doc_subsubsection">
6773 <a name="int_umul_overflow">'<tt>llvm.umul.with.overflow.*</tt>' Intrinsics</a>
6774</div>
6775
6776<div class="doc_text">
6777
6778<h5>Syntax:</h5>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]6779<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]6780 on any integer bit width.</p>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]6781
6782<pre>
6783 declare {i16, i1} @llvm.umul.with.overflow.i16(i16 %a, i16 %b)
6784 declare {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
6785 declare {i64, i1} @llvm.umul.with.overflow.i64(i64 %a, i64 %b)
6786</pre>
6787
6788<h5>Overview:</h5>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]6789<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6790 a unsigned multiplication of the two arguments, and indicate whether an
6791 overflow occurred during the unsigned multiplication.</p>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]6792
6793<h5>Arguments:</h5>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]6794<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]6795 be of integer types of any bit width, but they must have the same bit
6796 width. The second element of the result structure must be of
6797 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6798 undergo unsigned multiplication.</p>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]6799
6800<h5>Semantics:</h5>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]6801<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6802 an unsigned multiplication of the two arguments. They return a structure
6803 &mdash; the first element of which is the multiplication, and the second
6804 element of which is a bit specifying if the unsigned multiplication resulted
6805 in an overflow.</p>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]6806
6807<h5>Examples:</h5>
6808<pre>
6809 %res = call {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
6810 %sum = extractvalue {i32, i1} %res, 0
6811 %obit = extractvalue {i32, i1} %res, 1
6812 br i1 %obit, label %overflow, label %normal
6813</pre>
6814
6815</div>
6816
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]6817<!-- ======================================================================= -->
6818<div class="doc_subsection">
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]6819 <a name="int_fp16">Half Precision Floating Point Intrinsics</a>
6820</div>
6821
6822<div class="doc_text">
6823
Chris Lattner022a9fb2010-03-15 04:12:21 +0000[diff] [blame]6824<p>Half precision floating point is a storage-only format. This means that it is
6825 a dense encoding (in memory) but does not support computation in the
6826 format.</p>
Chris Lattnerbbd8bd32010-03-14 23:03:31 +0000[diff] [blame]6827
Chris Lattner022a9fb2010-03-15 04:12:21 +0000[diff] [blame]6828<p>This means that code must first load the half-precision floating point
Chris Lattnerbbd8bd32010-03-14 23:03:31 +0000[diff] [blame]6829 value as an i16, then convert it to float with <a
6830 href="#int_convert_from_fp16"><tt>llvm.convert.from.fp16</tt></a>.
6831 Computation can then be performed on the float value (including extending to
Chris Lattner022a9fb2010-03-15 04:12:21 +0000[diff] [blame]6832 double etc). To store the value back to memory, it is first converted to
6833 float if needed, then converted to i16 with
Chris Lattnerbbd8bd32010-03-14 23:03:31 +0000[diff] [blame]6834 <a href="#int_convert_to_fp16"><tt>llvm.convert.to.fp16</tt></a>, then
6835 storing as an i16 value.</p>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]6836</div>
6837
6838<!-- _______________________________________________________________________ -->
6839<div class="doc_subsubsection">
Chris Lattnerbbd8bd32010-03-14 23:03:31 +0000[diff] [blame]6840 <a name="int_convert_to_fp16">'<tt>llvm.convert.to.fp16</tt>' Intrinsic</a>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]6841</div>
6842
6843<div class="doc_text">
6844
6845<h5>Syntax:</h5>
6846<pre>
6847 declare i16 @llvm.convert.to.fp16(f32 %a)
6848</pre>
6849
6850<h5>Overview:</h5>
6851<p>The '<tt>llvm.convert.to.fp16</tt>' intrinsic function performs
6852 a conversion from single precision floating point format to half precision
6853 floating point format.</p>
6854
6855<h5>Arguments:</h5>
6856<p>The intrinsic function contains single argument - the value to be
6857 converted.</p>
6858
6859<h5>Semantics:</h5>
6860<p>The '<tt>llvm.convert.to.fp16</tt>' intrinsic function performs
6861 a conversion from single precision floating point format to half precision
Chris Lattner022a9fb2010-03-15 04:12:21 +0000[diff] [blame]6862 floating point format. The return value is an <tt>i16</tt> which
Chris Lattnerbbd8bd32010-03-14 23:03:31 +0000[diff] [blame]6863 contains the converted number.</p>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]6864
6865<h5>Examples:</h5>
6866<pre>
6867 %res = call i16 @llvm.convert.to.fp16(f32 %a)
6868 store i16 %res, i16* @x, align 2
6869</pre>
6870
6871</div>
6872
6873<!-- _______________________________________________________________________ -->
6874<div class="doc_subsubsection">
Chris Lattnerbbd8bd32010-03-14 23:03:31 +0000[diff] [blame]6875 <a name="int_convert_from_fp16">'<tt>llvm.convert.from.fp16</tt>' Intrinsic</a>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]6876</div>
6877
6878<div class="doc_text">
6879
6880<h5>Syntax:</h5>
6881<pre>
6882 declare f32 @llvm.convert.from.fp16(i16 %a)
6883</pre>
6884
6885<h5>Overview:</h5>
6886<p>The '<tt>llvm.convert.from.fp16</tt>' intrinsic function performs
6887 a conversion from half precision floating point format to single precision
6888 floating point format.</p>
6889
6890<h5>Arguments:</h5>
6891<p>The intrinsic function contains single argument - the value to be
6892 converted.</p>
6893
6894<h5>Semantics:</h5>
6895<p>The '<tt>llvm.convert.from.fp16</tt>' intrinsic function performs a
Chris Lattner022a9fb2010-03-15 04:12:21 +0000[diff] [blame]6896 conversion from half single precision floating point format to single
Chris Lattnerbbd8bd32010-03-14 23:03:31 +0000[diff] [blame]6897 precision floating point format. The input half-float value is represented by
6898 an <tt>i16</tt> value.</p>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]6899
6900<h5>Examples:</h5>
6901<pre>
6902 %a = load i16* @x, align 2
6903 %res = call f32 @llvm.convert.from.fp16(i16 %a)
6904</pre>
6905
6906</div>
6907
6908<!-- ======================================================================= -->
6909<div class="doc_subsection">
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]6910 <a name="int_debugger">Debugger Intrinsics</a>
6911</div>
6912
6913<div class="doc_text">
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]6914
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6915<p>The LLVM debugger intrinsics (which all start with <tt>llvm.dbg.</tt>
6916 prefix), are described in
6917 the <a href="SourceLevelDebugging.html#format_common_intrinsics">LLVM Source
6918 Level Debugging</a> document.</p>
6919
6920</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]6921
Jim Laskey2211f492007-03-14 19:31:19 +0000[diff] [blame]6922<!-- ======================================================================= -->
6923<div class="doc_subsection">
6924 <a name="int_eh">Exception Handling Intrinsics</a>
6925</div>
6926
6927<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6928
6929<p>The LLVM exception handling intrinsics (which all start with
6930 <tt>llvm.eh.</tt> prefix), are described in
6931 the <a href="ExceptionHandling.html#format_common_intrinsics">LLVM Exception
6932 Handling</a> document.</p>
6933
Jim Laskey2211f492007-03-14 19:31:19 +0000[diff] [blame]6934</div>
6935
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]6936<!-- ======================================================================= -->
6937<div class="doc_subsection">
Duncan Sands86e01192007-09-11 14:10:23 +0000[diff] [blame]6938 <a name="int_trampoline">Trampoline Intrinsic</a>
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]6939</div>
6940
6941<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6942
6943<p>This intrinsic makes it possible to excise one parameter, marked with
6944 the <tt>nest</tt> attribute, from a function. The result is a callable
6945 function pointer lacking the nest parameter - the caller does not need to
6946 provide a value for it. Instead, the value to use is stored in advance in a
6947 "trampoline", a block of memory usually allocated on the stack, which also
6948 contains code to splice the nest value into the argument list. This is used
6949 to implement the GCC nested function address extension.</p>
6950
6951<p>For example, if the function is
6952 <tt>i32 f(i8* nest %c, i32 %x, i32 %y)</tt> then the resulting function
6953 pointer has signature <tt>i32 (i32, i32)*</tt>. It can be created as
6954 follows:</p>
6955
6956<div class="doc_code">
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]6957<pre>
Duncan Sands86e01192007-09-11 14:10:23 +0000[diff] [blame]6958 %tramp = alloca [10 x i8], align 4 ; size and alignment only correct for X86
6959 %tramp1 = getelementptr [10 x i8]* %tramp, i32 0, i32 0
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]6960 %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]6961 %fp = bitcast i8* %p to i32 (i32, i32)*
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]6962</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6963</div>
6964
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]6965<p>The call <tt>%val = call i32 %fp(i32 %x, i32 %y)</tt> is then equivalent
6966 to <tt>%val = call i32 %f(i8* %nval, i32 %x, i32 %y)</tt>.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6967
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]6968</div>
6969
6970<!-- _______________________________________________________________________ -->
6971<div class="doc_subsubsection">
6972 <a name="int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a>
6973</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6974
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]6975<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6976
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]6977<h5>Syntax:</h5>
6978<pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6979 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]6980</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6981
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]6982<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6983<p>This fills the memory pointed to by <tt>tramp</tt> with code and returns a
6984 function pointer suitable for executing it.</p>
6985
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]6986<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6987<p>The <tt>llvm.init.trampoline</tt> intrinsic takes three arguments, all
6988 pointers. The <tt>tramp</tt> argument must point to a sufficiently large and
6989 sufficiently aligned block of memory; this memory is written to by the
6990 intrinsic. Note that the size and the alignment are target-specific - LLVM
6991 currently provides no portable way of determining them, so a front-end that
6992 generates this intrinsic needs to have some target-specific knowledge.
6993 The <tt>func</tt> argument must hold a function bitcast to
6994 an <tt>i8*</tt>.</p>
6995
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]6996<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6997<p>The block of memory pointed to by <tt>tramp</tt> is filled with target
6998 dependent code, turning it into a function. A pointer to this function is
6999 returned, but needs to be bitcast to an <a href="#int_trampoline">appropriate
7000 function pointer type</a> before being called. The new function's signature
7001 is the same as that of <tt>func</tt> with any arguments marked with
7002 the <tt>nest</tt> attribute removed. At most one such <tt>nest</tt> argument
7003 is allowed, and it must be of pointer type. Calling the new function is
7004 equivalent to calling <tt>func</tt> with the same argument list, but
7005 with <tt>nval</tt> used for the missing <tt>nest</tt> argument. If, after
7006 calling <tt>llvm.init.trampoline</tt>, the memory pointed to
7007 by <tt>tramp</tt> is modified, then the effect of any later call to the
7008 returned function pointer is undefined.</p>
7009
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]7010</div>
7011
7012<!-- ======================================================================= -->
7013<div class="doc_subsection">
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7014 <a name="int_atomics">Atomic Operations and Synchronization Intrinsics</a>
7015</div>
7016
7017<div class="doc_text">
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7018
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7019<p>These intrinsic functions expand the "universal IR" of LLVM to represent
7020 hardware constructs for atomic operations and memory synchronization. This
7021 provides an interface to the hardware, not an interface to the programmer. It
7022 is aimed at a low enough level to allow any programming models or APIs
7023 (Application Programming Interfaces) which need atomic behaviors to map
7024 cleanly onto it. It is also modeled primarily on hardware behavior. Just as
7025 hardware provides a "universal IR" for source languages, it also provides a
7026 starting point for developing a "universal" atomic operation and
7027 synchronization IR.</p>
7028
7029<p>These do <em>not</em> form an API such as high-level threading libraries,
7030 software transaction memory systems, atomic primitives, and intrinsic
7031 functions as found in BSD, GNU libc, atomic_ops, APR, and other system and
7032 application libraries. The hardware interface provided by LLVM should allow
7033 a clean implementation of all of these APIs and parallel programming models.
7034 No one model or paradigm should be selected above others unless the hardware
7035 itself ubiquitously does so.</p>
7036
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7037</div>
7038
7039<!-- _______________________________________________________________________ -->
7040<div class="doc_subsubsection">
7041 <a name="int_memory_barrier">'<tt>llvm.memory.barrier</tt>' Intrinsic</a>
7042</div>
7043<div class="doc_text">
7044<h5>Syntax:</h5>
7045<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7046 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]7047</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7048
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7049<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7050<p>The <tt>llvm.memory.barrier</tt> intrinsic guarantees ordering between
7051 specific pairs of memory access types.</p>
7052
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7053<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7054<p>The <tt>llvm.memory.barrier</tt> intrinsic requires five boolean arguments.
7055 The first four arguments enables a specific barrier as listed below. The
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]7056 fifth argument specifies that the barrier applies to io or device or uncached
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7057 memory.</p>
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7058
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7059<ul>
7060 <li><tt>ll</tt>: load-load barrier</li>
7061 <li><tt>ls</tt>: load-store barrier</li>
7062 <li><tt>sl</tt>: store-load barrier</li>
7063 <li><tt>ss</tt>: store-store barrier</li>
7064 <li><tt>device</tt>: barrier applies to device and uncached memory also.</li>
7065</ul>
7066
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7067<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7068<p>This intrinsic causes the system to enforce some ordering constraints upon
7069 the loads and stores of the program. This barrier does not
7070 indicate <em>when</em> any events will occur, it only enforces
7071 an <em>order</em> in which they occur. For any of the specified pairs of load
7072 and store operations (f.ex. load-load, or store-load), all of the first
7073 operations preceding the barrier will complete before any of the second
7074 operations succeeding the barrier begin. Specifically the semantics for each
7075 pairing is as follows:</p>
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7076
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7077<ul>
7078 <li><tt>ll</tt>: All loads before the barrier must complete before any load
7079 after the barrier begins.</li>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]7080 <li><tt>ls</tt>: All loads before the barrier must complete before any
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7081 store after the barrier begins.</li>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]7082 <li><tt>ss</tt>: All stores before the barrier must complete before any
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7083 store after the barrier begins.</li>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]7084 <li><tt>sl</tt>: All stores before the barrier must complete before any
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7085 load after the barrier begins.</li>
7086</ul>
7087
7088<p>These semantics are applied with a logical "and" behavior when more than one
7089 is enabled in a single memory barrier intrinsic.</p>
7090
7091<p>Backends may implement stronger barriers than those requested when they do
7092 not support as fine grained a barrier as requested. Some architectures do
7093 not need all types of barriers and on such architectures, these become
7094 noops.</p>
7095
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7096<h5>Example:</h5>
7097<pre>
Victor Hernandeza70c6df2009-10-26 23:44:29 +0000[diff] [blame]7098%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7099%ptr = bitcast i8* %mallocP to i32*
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7100 store i32 4, %ptr
7101
7102%result1 = load i32* %ptr <i>; yields {i32}:result1 = 4</i>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7103 call void @llvm.memory.barrier(i1 false, i1 true, i1 false, i1 false)
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7104 <i>; guarantee the above finishes</i>
7105 store i32 8, %ptr <i>; before this begins</i>
7106</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7107
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7108</div>
7109
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7110<!-- _______________________________________________________________________ -->
7111<div class="doc_subsubsection">
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7112 <a name="int_atomic_cmp_swap">'<tt>llvm.atomic.cmp.swap.*</tt>' Intrinsic</a>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7113</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7114
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7115<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7116
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7117<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7118<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.cmp.swap</tt> on
7119 any integer bit width and for different address spaces. Not all targets
7120 support all bit widths however.</p>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7121
7122<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7123 declare i8 @llvm.atomic.cmp.swap.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;cmp&gt;, i8 &lt;val&gt;)
7124 declare i16 @llvm.atomic.cmp.swap.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;cmp&gt;, i16 &lt;val&gt;)
7125 declare i32 @llvm.atomic.cmp.swap.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;cmp&gt;, i32 &lt;val&gt;)
7126 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]7127</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7128
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7129<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7130<p>This loads a value in memory and compares it to a given value. If they are
7131 equal, it stores a new value into the memory.</p>
7132
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7133<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7134<p>The <tt>llvm.atomic.cmp.swap</tt> intrinsic takes three arguments. The result
7135 as well as both <tt>cmp</tt> and <tt>val</tt> must be integer values with the
7136 same bit width. The <tt>ptr</tt> argument must be a pointer to a value of
7137 this integer type. While any bit width integer may be used, targets may only
7138 lower representations they support in hardware.</p>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7139
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7140<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7141<p>This entire intrinsic must be executed atomically. It first loads the value
7142 in memory pointed to by <tt>ptr</tt> and compares it with the
7143 value <tt>cmp</tt>. If they are equal, <tt>val</tt> is stored into the
7144 memory. The loaded value is yielded in all cases. This provides the
7145 equivalent of an atomic compare-and-swap operation within the SSA
7146 framework.</p>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7147
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7148<h5>Examples:</h5>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7149<pre>
Victor Hernandeza70c6df2009-10-26 23:44:29 +0000[diff] [blame]7150%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7151%ptr = bitcast i8* %mallocP to i32*
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7152 store i32 4, %ptr
7153
7154%val1 = add i32 4, 4
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7155%result1 = call i32 @llvm.atomic.cmp.swap.i32.p0i32(i32* %ptr, i32 4, %val1)
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7156 <i>; yields {i32}:result1 = 4</i>
7157%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
7158%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
7159
7160%val2 = add i32 1, 1
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7161%result2 = call i32 @llvm.atomic.cmp.swap.i32.p0i32(i32* %ptr, i32 5, %val2)
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7162 <i>; yields {i32}:result2 = 8</i>
7163%stored2 = icmp eq i32 %result2, 5 <i>; yields {i1}:stored2 = false</i>
7164
7165%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 8</i>
7166</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7167
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7168</div>
7169
7170<!-- _______________________________________________________________________ -->
7171<div class="doc_subsubsection">
7172 <a name="int_atomic_swap">'<tt>llvm.atomic.swap.*</tt>' Intrinsic</a>
7173</div>
7174<div class="doc_text">
7175<h5>Syntax:</h5>
7176
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7177<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.swap</tt> on any
7178 integer bit width. Not all targets support all bit widths however.</p>
7179
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7180<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7181 declare i8 @llvm.atomic.swap.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;val&gt;)
7182 declare i16 @llvm.atomic.swap.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;val&gt;)
7183 declare i32 @llvm.atomic.swap.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;val&gt;)
7184 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]7185</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7186
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7187<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7188<p>This intrinsic loads the value stored in memory at <tt>ptr</tt> and yields
7189 the value from memory. It then stores the value in <tt>val</tt> in the memory
7190 at <tt>ptr</tt>.</p>
7191
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7192<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7193<p>The <tt>llvm.atomic.swap</tt> intrinsic takes two arguments. Both
7194 the <tt>val</tt> argument and the result must be integers of the same bit
7195 width. The first argument, <tt>ptr</tt>, must be a pointer to a value of this
7196 integer type. The targets may only lower integer representations they
7197 support.</p>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7198
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7199<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7200<p>This intrinsic loads the value pointed to by <tt>ptr</tt>, yields it, and
7201 stores <tt>val</tt> back into <tt>ptr</tt> atomically. This provides the
7202 equivalent of an atomic swap operation within the SSA framework.</p>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7203
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7204<h5>Examples:</h5>
7205<pre>
Victor Hernandeza70c6df2009-10-26 23:44:29 +0000[diff] [blame]7206%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7207%ptr = bitcast i8* %mallocP to i32*
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7208 store i32 4, %ptr
7209
7210%val1 = add i32 4, 4
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7211%result1 = call i32 @llvm.atomic.swap.i32.p0i32(i32* %ptr, i32 %val1)
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7212 <i>; yields {i32}:result1 = 4</i>
7213%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
7214%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
7215
7216%val2 = add i32 1, 1
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7217%result2 = call i32 @llvm.atomic.swap.i32.p0i32(i32* %ptr, i32 %val2)
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7218 <i>; yields {i32}:result2 = 8</i>
7219
7220%stored2 = icmp eq i32 %result2, 8 <i>; yields {i1}:stored2 = true</i>
7221%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 2</i>
7222</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7223
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7224</div>
7225
7226<!-- _______________________________________________________________________ -->
7227<div class="doc_subsubsection">
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7228 <a name="int_atomic_load_add">'<tt>llvm.atomic.load.add.*</tt>' Intrinsic</a>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7229
7230</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7231
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7232<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7233
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7234<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7235<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.load.add</tt> on
7236 any integer bit width. Not all targets support all bit widths however.</p>
7237
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7238<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7239 declare i8 @llvm.atomic.load.add.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7240 declare i16 @llvm.atomic.load.add.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7241 declare i32 @llvm.atomic.load.add.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7242 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]7243</pre>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7244
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7245<h5>Overview:</h5>
7246<p>This intrinsic adds <tt>delta</tt> to the value stored in memory
7247 at <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.</p>
7248
7249<h5>Arguments:</h5>
7250<p>The intrinsic takes two arguments, the first a pointer to an integer value
7251 and the second an integer value. The result is also an integer value. These
7252 integer types can have any bit width, but they must all have the same bit
7253 width. The targets may only lower integer representations they support.</p>
7254
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7255<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7256<p>This intrinsic does a series of operations atomically. It first loads the
7257 value stored at <tt>ptr</tt>. It then adds <tt>delta</tt>, stores the result
7258 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]7259
7260<h5>Examples:</h5>
7261<pre>
Victor Hernandeza70c6df2009-10-26 23:44:29 +0000[diff] [blame]7262%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7263%ptr = bitcast i8* %mallocP to i32*
7264 store i32 4, %ptr
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7265%result1 = call i32 @llvm.atomic.load.add.i32.p0i32(i32* %ptr, i32 4)
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7266 <i>; yields {i32}:result1 = 4</i>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7267%result2 = call i32 @llvm.atomic.load.add.i32.p0i32(i32* %ptr, i32 2)
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7268 <i>; yields {i32}:result2 = 8</i>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7269%result3 = call i32 @llvm.atomic.load.add.i32.p0i32(i32* %ptr, i32 5)
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7270 <i>; yields {i32}:result3 = 10</i>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7271%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 15</i>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7272</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7273
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7274</div>
7275
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7276<!-- _______________________________________________________________________ -->
7277<div class="doc_subsubsection">
7278 <a name="int_atomic_load_sub">'<tt>llvm.atomic.load.sub.*</tt>' Intrinsic</a>
7279
7280</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7281
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7282<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7283
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7284<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7285<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.load.sub</tt> on
7286 any integer bit width and for different address spaces. Not all targets
7287 support all bit widths however.</p>
7288
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7289<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7290 declare i8 @llvm.atomic.load.sub.i8.p0i32(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7291 declare i16 @llvm.atomic.load.sub.i16.p0i32(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7292 declare i32 @llvm.atomic.load.sub.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7293 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]7294</pre>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7295
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7296<h5>Overview:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]7297<p>This intrinsic subtracts <tt>delta</tt> to the value stored in memory at
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7298 <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.</p>
7299
7300<h5>Arguments:</h5>
7301<p>The intrinsic takes two arguments, the first a pointer to an integer value
7302 and the second an integer value. The result is also an integer value. These
7303 integer types can have any bit width, but they must all have the same bit
7304 width. The targets may only lower integer representations they support.</p>
7305
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7306<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7307<p>This intrinsic does a series of operations atomically. It first loads the
7308 value stored at <tt>ptr</tt>. It then subtracts <tt>delta</tt>, stores the
7309 result to <tt>ptr</tt>. It yields the original value stored
7310 at <tt>ptr</tt>.</p>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7311
7312<h5>Examples:</h5>
7313<pre>
Victor Hernandeza70c6df2009-10-26 23:44:29 +0000[diff] [blame]7314%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7315%ptr = bitcast i8* %mallocP to i32*
7316 store i32 8, %ptr
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7317%result1 = call i32 @llvm.atomic.load.sub.i32.p0i32(i32* %ptr, i32 4)
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7318 <i>; yields {i32}:result1 = 8</i>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7319%result2 = call i32 @llvm.atomic.load.sub.i32.p0i32(i32* %ptr, i32 2)
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7320 <i>; yields {i32}:result2 = 4</i>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7321%result3 = call i32 @llvm.atomic.load.sub.i32.p0i32(i32* %ptr, i32 5)
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7322 <i>; yields {i32}:result3 = 2</i>
7323%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = -3</i>
7324</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7325
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7326</div>
7327
7328<!-- _______________________________________________________________________ -->
7329<div class="doc_subsubsection">
7330 <a name="int_atomic_load_and">'<tt>llvm.atomic.load.and.*</tt>' Intrinsic</a><br>
7331 <a name="int_atomic_load_nand">'<tt>llvm.atomic.load.nand.*</tt>' Intrinsic</a><br>
7332 <a name="int_atomic_load_or">'<tt>llvm.atomic.load.or.*</tt>' Intrinsic</a><br>
7333 <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]7334</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7335
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7336<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7337
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7338<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7339<p>These are overloaded intrinsics. You can
7340 use <tt>llvm.atomic.load_and</tt>, <tt>llvm.atomic.load_nand</tt>,
7341 <tt>llvm.atomic.load_or</tt>, and <tt>llvm.atomic.load_xor</tt> on any integer
7342 bit width and for different address spaces. Not all targets support all bit
7343 widths however.</p>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7344
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7345<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7346 declare i8 @llvm.atomic.load.and.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7347 declare i16 @llvm.atomic.load.and.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7348 declare i32 @llvm.atomic.load.and.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7349 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]7350</pre>
7351
7352<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7353 declare i8 @llvm.atomic.load.or.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7354 declare i16 @llvm.atomic.load.or.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7355 declare i32 @llvm.atomic.load.or.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7356 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]7357</pre>
7358
7359<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7360 declare i8 @llvm.atomic.load.nand.i8.p0i32(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7361 declare i16 @llvm.atomic.load.nand.i16.p0i32(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7362 declare i32 @llvm.atomic.load.nand.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7363 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]7364</pre>
7365
7366<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7367 declare i8 @llvm.atomic.load.xor.i8.p0i32(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7368 declare i16 @llvm.atomic.load.xor.i16.p0i32(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7369 declare i32 @llvm.atomic.load.xor.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7370 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]7371</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7372
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7373<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7374<p>These intrinsics bitwise the operation (and, nand, or, xor) <tt>delta</tt> to
7375 the value stored in memory at <tt>ptr</tt>. It yields the original value
7376 at <tt>ptr</tt>.</p>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7377
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7378<h5>Arguments:</h5>
7379<p>These intrinsics take two arguments, the first a pointer to an integer value
7380 and the second an integer value. The result is also an integer value. These
7381 integer types can have any bit width, but they must all have the same bit
7382 width. The targets may only lower integer representations they support.</p>
7383
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7384<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7385<p>These intrinsics does a series of operations atomically. They first load the
7386 value stored at <tt>ptr</tt>. They then do the bitwise
7387 operation <tt>delta</tt>, store the result to <tt>ptr</tt>. They yield the
7388 original value stored at <tt>ptr</tt>.</p>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7389
7390<h5>Examples:</h5>
7391<pre>
Victor Hernandeza70c6df2009-10-26 23:44:29 +0000[diff] [blame]7392%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7393%ptr = bitcast i8* %mallocP to i32*
7394 store i32 0x0F0F, %ptr
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7395%result0 = call i32 @llvm.atomic.load.nand.i32.p0i32(i32* %ptr, i32 0xFF)
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7396 <i>; yields {i32}:result0 = 0x0F0F</i>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7397%result1 = call i32 @llvm.atomic.load.and.i32.p0i32(i32* %ptr, i32 0xFF)
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7398 <i>; yields {i32}:result1 = 0xFFFFFFF0</i>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7399%result2 = call i32 @llvm.atomic.load.or.i32.p0i32(i32* %ptr, i32 0F)
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7400 <i>; yields {i32}:result2 = 0xF0</i>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7401%result3 = call i32 @llvm.atomic.load.xor.i32.p0i32(i32* %ptr, i32 0F)
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7402 <i>; yields {i32}:result3 = FF</i>
7403%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = F0</i>
7404</pre>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7405
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7406</div>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7407
7408<!-- _______________________________________________________________________ -->
7409<div class="doc_subsubsection">
7410 <a name="int_atomic_load_max">'<tt>llvm.atomic.load.max.*</tt>' Intrinsic</a><br>
7411 <a name="int_atomic_load_min">'<tt>llvm.atomic.load.min.*</tt>' Intrinsic</a><br>
7412 <a name="int_atomic_load_umax">'<tt>llvm.atomic.load.umax.*</tt>' Intrinsic</a><br>
7413 <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]7414</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7415
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7416<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7417
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7418<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7419<p>These are overloaded intrinsics. You can use <tt>llvm.atomic.load_max</tt>,
7420 <tt>llvm.atomic.load_min</tt>, <tt>llvm.atomic.load_umax</tt>, and
7421 <tt>llvm.atomic.load_umin</tt> on any integer bit width and for different
7422 address spaces. Not all targets support all bit widths however.</p>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7423
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7424<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7425 declare i8 @llvm.atomic.load.max.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7426 declare i16 @llvm.atomic.load.max.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7427 declare i32 @llvm.atomic.load.max.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7428 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]7429</pre>
7430
7431<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7432 declare i8 @llvm.atomic.load.min.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7433 declare i16 @llvm.atomic.load.min.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7434 declare i32 @llvm.atomic.load.min.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7435 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]7436</pre>
7437
7438<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7439 declare i8 @llvm.atomic.load.umax.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7440 declare i16 @llvm.atomic.load.umax.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7441 declare i32 @llvm.atomic.load.umax.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7442 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]7443</pre>
7444
7445<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7446 declare i8 @llvm.atomic.load.umin.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7447 declare i16 @llvm.atomic.load.umin.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7448 declare i32 @llvm.atomic.load.umin.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7449 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]7450</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7451
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7452<h5>Overview:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]7453<p>These intrinsics takes the signed or unsigned minimum or maximum of
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7454 <tt>delta</tt> and the value stored in memory at <tt>ptr</tt>. It yields the
7455 original value at <tt>ptr</tt>.</p>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7456
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7457<h5>Arguments:</h5>
7458<p>These intrinsics take two arguments, the first a pointer to an integer value
7459 and the second an integer value. The result is also an integer value. These
7460 integer types can have any bit width, but they must all have the same bit
7461 width. The targets may only lower integer representations they support.</p>
7462
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7463<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7464<p>These intrinsics does a series of operations atomically. They first load the
7465 value stored at <tt>ptr</tt>. They then do the signed or unsigned min or
7466 max <tt>delta</tt> and the value, store the result to <tt>ptr</tt>. They
7467 yield the original value stored at <tt>ptr</tt>.</p>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7468
7469<h5>Examples:</h5>
7470<pre>
Victor Hernandeza70c6df2009-10-26 23:44:29 +0000[diff] [blame]7471%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7472%ptr = bitcast i8* %mallocP to i32*
7473 store i32 7, %ptr
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7474%result0 = call i32 @llvm.atomic.load.min.i32.p0i32(i32* %ptr, i32 -2)
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7475 <i>; yields {i32}:result0 = 7</i>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7476%result1 = call i32 @llvm.atomic.load.max.i32.p0i32(i32* %ptr, i32 8)
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7477 <i>; yields {i32}:result1 = -2</i>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7478%result2 = call i32 @llvm.atomic.load.umin.i32.p0i32(i32* %ptr, i32 10)
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7479 <i>; yields {i32}:result2 = 8</i>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7480%result3 = call i32 @llvm.atomic.load.umax.i32.p0i32(i32* %ptr, i32 30)
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7481 <i>; yields {i32}:result3 = 8</i>
7482%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 30</i>
7483</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7484
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7485</div>
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7486
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]7487
7488<!-- ======================================================================= -->
7489<div class="doc_subsection">
7490 <a name="int_memorymarkers">Memory Use Markers</a>
7491</div>
7492
7493<div class="doc_text">
7494
7495<p>This class of intrinsics exists to information about the lifetime of memory
7496 objects and ranges where variables are immutable.</p>
7497
7498</div>
7499
7500<!-- _______________________________________________________________________ -->
7501<div class="doc_subsubsection">
7502 <a name="int_lifetime_start">'<tt>llvm.lifetime.start</tt>' Intrinsic</a>
7503</div>
7504
7505<div class="doc_text">
7506
7507<h5>Syntax:</h5>
7508<pre>
7509 declare void @llvm.lifetime.start(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7510</pre>
7511
7512<h5>Overview:</h5>
7513<p>The '<tt>llvm.lifetime.start</tt>' intrinsic specifies the start of a memory
7514 object's lifetime.</p>
7515
7516<h5>Arguments:</h5>
Nick Lewycky9bc89042009-10-13 07:57:33 +0000[diff] [blame]7517<p>The first argument is a constant integer representing the size of the
7518 object, or -1 if it is variable sized. The second argument is a pointer to
7519 the object.</p>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]7520
7521<h5>Semantics:</h5>
7522<p>This intrinsic indicates that before this point in the code, the value of the
7523 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]7524 never be used and has an undefined value. A load from the pointer that
7525 precedes this intrinsic can be replaced with
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]7526 <tt>'<a href="#undefvalues">undef</a>'</tt>.</p>
7527
7528</div>
7529
7530<!-- _______________________________________________________________________ -->
7531<div class="doc_subsubsection">
7532 <a name="int_lifetime_end">'<tt>llvm.lifetime.end</tt>' Intrinsic</a>
7533</div>
7534
7535<div class="doc_text">
7536
7537<h5>Syntax:</h5>
7538<pre>
7539 declare void @llvm.lifetime.end(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7540</pre>
7541
7542<h5>Overview:</h5>
7543<p>The '<tt>llvm.lifetime.end</tt>' intrinsic specifies the end of a memory
7544 object's lifetime.</p>
7545
7546<h5>Arguments:</h5>
Nick Lewycky9bc89042009-10-13 07:57:33 +0000[diff] [blame]7547<p>The first argument is a constant integer representing the size of the
7548 object, or -1 if it is variable sized. The second argument is a pointer to
7549 the object.</p>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]7550
7551<h5>Semantics:</h5>
7552<p>This intrinsic indicates that after this point in the code, the value of the
7553 memory pointed to by <tt>ptr</tt> is dead. This means that it is known to
7554 never be used and has an undefined value. Any stores into the memory object
7555 following this intrinsic may be removed as dead.
7556
7557</div>
7558
7559<!-- _______________________________________________________________________ -->
7560<div class="doc_subsubsection">
7561 <a name="int_invariant_start">'<tt>llvm.invariant.start</tt>' Intrinsic</a>
7562</div>
7563
7564<div class="doc_text">
7565
7566<h5>Syntax:</h5>
7567<pre>
7568 declare {}* @llvm.invariant.start(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;) readonly
7569</pre>
7570
7571<h5>Overview:</h5>
7572<p>The '<tt>llvm.invariant.start</tt>' intrinsic specifies that the contents of
7573 a memory object will not change.</p>
7574
7575<h5>Arguments:</h5>
Nick Lewycky9bc89042009-10-13 07:57:33 +0000[diff] [blame]7576<p>The first argument is a constant integer representing the size of the
7577 object, or -1 if it is variable sized. The second argument is a pointer to
7578 the object.</p>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]7579
7580<h5>Semantics:</h5>
7581<p>This intrinsic indicates that until an <tt>llvm.invariant.end</tt> that uses
7582 the return value, the referenced memory location is constant and
7583 unchanging.</p>
7584
7585</div>
7586
7587<!-- _______________________________________________________________________ -->
7588<div class="doc_subsubsection">
7589 <a name="int_invariant_end">'<tt>llvm.invariant.end</tt>' Intrinsic</a>
7590</div>
7591
7592<div class="doc_text">
7593
7594<h5>Syntax:</h5>
7595<pre>
7596 declare void @llvm.invariant.end({}* &lt;start&gt;, i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7597</pre>
7598
7599<h5>Overview:</h5>
7600<p>The '<tt>llvm.invariant.end</tt>' intrinsic specifies that the contents of
7601 a memory object are mutable.</p>
7602
7603<h5>Arguments:</h5>
7604<p>The first argument is the matching <tt>llvm.invariant.start</tt> intrinsic.
Nick Lewycky9bc89042009-10-13 07:57:33 +0000[diff] [blame]7605 The second argument is a constant integer representing the size of the
7606 object, or -1 if it is variable sized and the third argument is a pointer
7607 to the object.</p>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]7608
7609<h5>Semantics:</h5>
7610<p>This intrinsic indicates that the memory is mutable again.</p>
7611
7612</div>
7613
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7614<!-- ======================================================================= -->
7615<div class="doc_subsection">
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]7616 <a name="int_general">General Intrinsics</a>
7617</div>
7618
7619<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7620
7621<p>This class of intrinsics is designed to be generic and has no specific
7622 purpose.</p>
7623
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]7624</div>
7625
7626<!-- _______________________________________________________________________ -->
7627<div class="doc_subsubsection">
7628 <a name="int_var_annotation">'<tt>llvm.var.annotation</tt>' Intrinsic</a>
7629</div>
7630
7631<div class="doc_text">
7632
7633<h5>Syntax:</h5>
7634<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7635 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]7636</pre>
7637
7638<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7639<p>The '<tt>llvm.var.annotation</tt>' intrinsic.</p>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]7640
7641<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7642<p>The first argument is a pointer to a value, the second is a pointer to a
7643 global string, the third is a pointer to a global string which is the source
7644 file name, and the last argument is the line number.</p>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]7645
7646<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7647<p>This intrinsic allows annotation of local variables with arbitrary strings.
7648 This can be useful for special purpose optimizations that want to look for
7649 these annotations. These have no other defined use, they are ignored by code
7650 generation and optimization.</p>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]7651
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]7652</div>
7653
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]7654<!-- _______________________________________________________________________ -->
7655<div class="doc_subsubsection">
Tanya Lattner0186a652007-09-21 23:57:59 +0000[diff] [blame]7656 <a name="int_annotation">'<tt>llvm.annotation.*</tt>' Intrinsic</a>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]7657</div>
7658
7659<div class="doc_text">
7660
7661<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7662<p>This is an overloaded intrinsic. You can use '<tt>llvm.annotation</tt>' on
7663 any integer bit width.</p>
7664
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]7665<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7666 declare i8 @llvm.annotation.i8(i8 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
7667 declare i16 @llvm.annotation.i16(i16 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
7668 declare i32 @llvm.annotation.i32(i32 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
7669 declare i64 @llvm.annotation.i64(i64 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
7670 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]7671</pre>
7672
7673<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7674<p>The '<tt>llvm.annotation</tt>' intrinsic.</p>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]7675
7676<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7677<p>The first argument is an integer value (result of some expression), the
7678 second is a pointer to a global string, the third is a pointer to a global
7679 string which is the source file name, and the last argument is the line
7680 number. It returns the value of the first argument.</p>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]7681
7682<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7683<p>This intrinsic allows annotations to be put on arbitrary expressions with
7684 arbitrary strings. This can be useful for special purpose optimizations that
7685 want to look for these annotations. These have no other defined use, they
7686 are ignored by code generation and optimization.</p>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]7687
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]7688</div>
Jim Laskey2211f492007-03-14 19:31:19 +0000[diff] [blame]7689
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]7690<!-- _______________________________________________________________________ -->
7691<div class="doc_subsubsection">
7692 <a name="int_trap">'<tt>llvm.trap</tt>' Intrinsic</a>
7693</div>
7694
7695<div class="doc_text">
7696
7697<h5>Syntax:</h5>
7698<pre>
7699 declare void @llvm.trap()
7700</pre>
7701
7702<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7703<p>The '<tt>llvm.trap</tt>' intrinsic.</p>
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]7704
7705<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7706<p>None.</p>
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]7707
7708<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7709<p>This intrinsics is lowered to the target dependent trap instruction. If the
7710 target does not have a trap instruction, this intrinsic will be lowered to
7711 the call of the <tt>abort()</tt> function.</p>
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]7712
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]7713</div>
7714
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]7715<!-- _______________________________________________________________________ -->
7716<div class="doc_subsubsection">
Misha Brukman50de2b22008-11-22 23:55:29 +0000[diff] [blame]7717 <a name="int_stackprotector">'<tt>llvm.stackprotector</tt>' Intrinsic</a>
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]7718</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7719
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]7720<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7721
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]7722<h5>Syntax:</h5>
7723<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7724 declare void @llvm.stackprotector(i8* &lt;guard&gt;, i8** &lt;slot&gt;)
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]7725</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7726
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]7727<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7728<p>The <tt>llvm.stackprotector</tt> intrinsic takes the <tt>guard</tt> and
7729 stores it onto the stack at <tt>slot</tt>. The stack slot is adjusted to
7730 ensure that it is placed on the stack before local variables.</p>
7731
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]7732<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7733<p>The <tt>llvm.stackprotector</tt> intrinsic requires two pointer
7734 arguments. The first argument is the value loaded from the stack
7735 guard <tt>@__stack_chk_guard</tt>. The second variable is an <tt>alloca</tt>
7736 that has enough space to hold the value of the guard.</p>
7737
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]7738<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7739<p>This intrinsic causes the prologue/epilogue inserter to force the position of
7740 the <tt>AllocaInst</tt> stack slot to be before local variables on the
7741 stack. This is to ensure that if a local variable on the stack is
7742 overwritten, it will destroy the value of the guard. When the function exits,
7743 the guard on the stack is checked against the original guard. If they're
7744 different, then the program aborts by calling the <tt>__stack_chk_fail()</tt>
7745 function.</p>
7746
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]7747</div>
7748
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]7749<!-- _______________________________________________________________________ -->
7750<div class="doc_subsubsection">
7751 <a name="int_objectsize">'<tt>llvm.objectsize</tt>' Intrinsic</a>
7752</div>
7753
7754<div class="doc_text">
7755
7756<h5>Syntax:</h5>
7757<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7758 declare i32 @llvm.objectsize.i32(i8* &lt;object&gt;, i1 &lt;type&gt;)
7759 declare i64 @llvm.objectsize.i64(i8* &lt;object&gt;, i1 &lt;type&gt;)
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]7760</pre>
7761
7762<h5>Overview:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]7763<p>The <tt>llvm.objectsize</tt> intrinsic is designed to provide information
Eric Christopher3070e162010-01-08 21:42:39 +0000[diff] [blame]7764 to the optimizers to discover at compile time either a) when an
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]7765 operation like memcpy will either overflow a buffer that corresponds to
7766 an object, or b) to determine that a runtime check for overflow isn't
7767 necessary. An object in this context means an allocation of a
Eric Christopher31e39bd2009-12-23 00:29:49 +0000[diff] [blame]7768 specific class, structure, array, or other object.</p>
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]7769
7770<h5>Arguments:</h5>
7771<p>The <tt>llvm.objectsize</tt> intrinsic takes two arguments. The first
Eric Christopher31e39bd2009-12-23 00:29:49 +0000[diff] [blame]7772 argument is a pointer to or into the <tt>object</tt>. The second argument
7773 is a boolean 0 or 1. This argument determines whether you want the
7774 maximum (0) or minimum (1) bytes remaining. This needs to be a literal 0 or
7775 1, variables are not allowed.</p>
7776
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]7777<h5>Semantics:</h5>
7778<p>The <tt>llvm.objectsize</tt> intrinsic is lowered to either a constant
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]7779 representing the size of the object concerned or <tt>i32/i64 -1 or 0</tt>
7780 (depending on the <tt>type</tt> argument if the size cannot be determined
7781 at compile time.</p>
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]7782
7783</div>
7784
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]7785<!-- *********************************************************************** -->
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]7786<hr>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]7787<address>
7788 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
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Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]7790 <a href="http://validator.w3.org/check/referer"><img
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Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]7792
7793 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
Reid Spencerca058542006-03-14 05:39:39 +0000[diff] [blame]7794 <a href="http://llvm.org">The LLVM Compiler Infrastructure</a><br>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]7795 Last modified: $Date$
7796</address>
Chris Lattnerb8f816e2008-01-04 04:33:49 +0000[diff] [blame]7797
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]7798</body>
7799</html>