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gerrit-public.fairphone.software / toolchain / llvm-project / 61110aed26d84705f00f6b48226458524ce86683 / . / llvm / docs / LangRef.html
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4<head>
5 <title>LLVM Assembly Language Reference Manual</title>
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7 <meta name="author" content="Chris Lattner">
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]8 <meta name="description"
Reid Spencercb84e432004-08-26 20:44:00 +0000[diff] [blame]9 content="LLVM Assembly Language Reference Manual.">
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]10 <link rel="stylesheet" href="llvm.css" type="text/css">
11</head>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]12
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]13<body>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]14
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]15<div class="doc_title"> LLVM Language Reference Manual </div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]16<ol>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]17 <li><a href="#abstract">Abstract</a></li>
18 <li><a href="#introduction">Introduction</a></li>
19 <li><a href="#identifiers">Identifiers</a></li>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]20 <li><a href="#highlevel">High Level Structure</a>
21 <ol>
22 <li><a href="#modulestructure">Module Structure</a></li>
Bill Wendlinga3c6f6b2009-07-20 01:03:30 +0000[diff] [blame]23 <li><a href="#linkage">Linkage Types</a>
24 <ol>
Bill Wendling8693ef82009-07-20 02:41:50 +0000[diff] [blame]25 <li><a href="#linkage_private">'<tt>private</tt>' Linkage</a></li>
26 <li><a href="#linkage_linker_private">'<tt>linker_private</tt>' Linkage</a></li>
27 <li><a href="#linkage_internal">'<tt>internal</tt>' Linkage</a></li>
28 <li><a href="#linkage_available_externally">'<tt>available_externally</tt>' Linkage</a></li>
29 <li><a href="#linkage_linkonce">'<tt>linkonce</tt>' Linkage</a></li>
30 <li><a href="#linkage_common">'<tt>common</tt>' Linkage</a></li>
31 <li><a href="#linkage_weak">'<tt>weak</tt>' Linkage</a></li>
32 <li><a href="#linkage_appending">'<tt>appending</tt>' Linkage</a></li>
33 <li><a href="#linkage_externweak">'<tt>extern_weak</tt>' Linkage</a></li>
Chris Lattner80d73c72009-10-10 18:26:06 +0000[diff] [blame]34 <li><a href="#linkage_linkonce_odr">'<tt>linkonce_odr</tt>' Linkage</a></li>
Bill Wendling8693ef82009-07-20 02:41:50 +0000[diff] [blame]35 <li><a href="#linkage_weak">'<tt>weak_odr</tt>' Linkage</a></li>
36 <li><a href="#linkage_external">'<tt>externally visible</tt>' Linkage</a></li>
37 <li><a href="#linkage_dllimport">'<tt>dllimport</tt>' Linkage</a></li>
38 <li><a href="#linkage_dllexport">'<tt>dllexport</tt>' Linkage</a></li>
Bill Wendlinga3c6f6b2009-07-20 01:03:30 +0000[diff] [blame]39 </ol>
40 </li>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]41 <li><a href="#callingconv">Calling Conventions</a></li>
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]42 <li><a href="#namedtypes">Named Types</a></li>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]43 <li><a href="#globalvars">Global Variables</a></li>
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]44 <li><a href="#functionstructure">Functions</a></li>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]45 <li><a href="#aliasstructure">Aliases</a></li>
Devang Pateld1a89692010-01-11 19:35:55 +0000[diff] [blame]46 <li><a href="#namedmetadatastructure">Named Metadata</a></li>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]47 <li><a href="#paramattrs">Parameter Attributes</a></li>
Devang Patel9eb525d2008-09-26 23:51:19 +0000[diff] [blame]48 <li><a href="#fnattrs">Function Attributes</a></li>
Gordon Henriksen71183b62007-12-10 03:18:06 +0000[diff] [blame]49 <li><a href="#gc">Garbage Collector Names</a></li>
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]50 <li><a href="#moduleasm">Module-Level Inline Assembly</a></li>
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]51 <li><a href="#datalayout">Data Layout</a></li>
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]52 <li><a href="#pointeraliasing">Pointer Aliasing Rules</a></li>
Jeffrey Yasskin5d284ae2010-04-26 21:21:24 +0000[diff] [blame]53 <li><a href="#volatile">Volatile Memory Accesses</a></li>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]54 </ol>
55 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]56 <li><a href="#typesystem">Type System</a>
57 <ol>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]58 <li><a href="#t_classifications">Type Classifications</a></li>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]59 <li><a href="#t_primitive">Primitive Types</a>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]60 <ol>
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]61 <li><a href="#t_integer">Integer Type</a></li>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]62 <li><a href="#t_floating">Floating Point Types</a></li>
63 <li><a href="#t_void">Void Type</a></li>
64 <li><a href="#t_label">Label Type</a></li>
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]65 <li><a href="#t_metadata">Metadata Type</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]66 </ol>
67 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]68 <li><a href="#t_derived">Derived Types</a>
69 <ol>
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]70 <li><a href="#t_aggregate">Aggregate Types</a>
71 <ol>
72 <li><a href="#t_array">Array Type</a></li>
73 <li><a href="#t_struct">Structure Type</a></li>
74 <li><a href="#t_pstruct">Packed Structure Type</a></li>
75 <li><a href="#t_union">Union Type</a></li>
76 <li><a href="#t_vector">Vector Type</a></li>
77 </ol>
78 </li>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]79 <li><a href="#t_function">Function Type</a></li>
80 <li><a href="#t_pointer">Pointer Type</a></li>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]81 <li><a href="#t_opaque">Opaque Type</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]82 </ol>
83 </li>
Chris Lattnercf7a5842009-02-02 07:32:36 +0000[diff] [blame]84 <li><a href="#t_uprefs">Type Up-references</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]85 </ol>
86 </li>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]87 <li><a href="#constants">Constants</a>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]88 <ol>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]89 <li><a href="#simpleconstants">Simple Constants</a></li>
Chris Lattner361bfcd2009-02-28 18:32:25 +0000[diff] [blame]90 <li><a href="#complexconstants">Complex Constants</a></li>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]91 <li><a href="#globalconstants">Global Variable and Function Addresses</a></li>
92 <li><a href="#undefvalues">Undefined Values</a></li>
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]93 <li><a href="#trapvalues">Trap Values</a></li>
Chris Lattner2bfd3202009-10-27 21:19:13 +0000[diff] [blame]94 <li><a href="#blockaddress">Addresses of Basic Blocks</a></li>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]95 <li><a href="#constantexprs">Constant Expressions</a></li>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]96 </ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]97 </li>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]98 <li><a href="#othervalues">Other Values</a>
99 <ol>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]100 <li><a href="#inlineasm">Inline Assembler Expressions</a></li>
Devang Pateld1a89692010-01-11 19:35:55 +0000[diff] [blame]101 <li><a href="#metadata">Metadata Nodes and Metadata Strings</a></li>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]102 </ol>
103 </li>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]104 <li><a href="#intrinsic_globals">Intrinsic Global Variables</a>
105 <ol>
106 <li><a href="#intg_used">The '<tt>llvm.used</tt>' Global Variable</a></li>
Chris Lattner58f9bb22009-07-20 06:14:25 +0000[diff] [blame]107 <li><a href="#intg_compiler_used">The '<tt>llvm.compiler.used</tt>'
108 Global Variable</a></li>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]109 <li><a href="#intg_global_ctors">The '<tt>llvm.global_ctors</tt>'
110 Global Variable</a></li>
111 <li><a href="#intg_global_dtors">The '<tt>llvm.global_dtors</tt>'
112 Global Variable</a></li>
113 </ol>
114 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]115 <li><a href="#instref">Instruction Reference</a>
116 <ol>
117 <li><a href="#terminators">Terminator Instructions</a>
118 <ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]119 <li><a href="#i_ret">'<tt>ret</tt>' Instruction</a></li>
120 <li><a href="#i_br">'<tt>br</tt>' Instruction</a></li>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]121 <li><a href="#i_switch">'<tt>switch</tt>' Instruction</a></li>
Chris Lattnerd04cb6d2009-10-28 00:19:10 +0000[diff] [blame]122 <li><a href="#i_indirectbr">'<tt>indirectbr</tt>' Instruction</a></li>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]123 <li><a href="#i_invoke">'<tt>invoke</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]124 <li><a href="#i_unwind">'<tt>unwind</tt>' Instruction</a></li>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]125 <li><a href="#i_unreachable">'<tt>unreachable</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]126 </ol>
127 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]128 <li><a href="#binaryops">Binary Operations</a>
129 <ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]130 <li><a href="#i_add">'<tt>add</tt>' Instruction</a></li>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]131 <li><a href="#i_fadd">'<tt>fadd</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]132 <li><a href="#i_sub">'<tt>sub</tt>' Instruction</a></li>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]133 <li><a href="#i_fsub">'<tt>fsub</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]134 <li><a href="#i_mul">'<tt>mul</tt>' Instruction</a></li>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]135 <li><a href="#i_fmul">'<tt>fmul</tt>' Instruction</a></li>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]136 <li><a href="#i_udiv">'<tt>udiv</tt>' Instruction</a></li>
137 <li><a href="#i_sdiv">'<tt>sdiv</tt>' Instruction</a></li>
138 <li><a href="#i_fdiv">'<tt>fdiv</tt>' Instruction</a></li>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]139 <li><a href="#i_urem">'<tt>urem</tt>' Instruction</a></li>
140 <li><a href="#i_srem">'<tt>srem</tt>' Instruction</a></li>
141 <li><a href="#i_frem">'<tt>frem</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]142 </ol>
143 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]144 <li><a href="#bitwiseops">Bitwise Binary Operations</a>
145 <ol>
Reid Spencer2ab01932007-02-02 13:57:07 +0000[diff] [blame]146 <li><a href="#i_shl">'<tt>shl</tt>' Instruction</a></li>
147 <li><a href="#i_lshr">'<tt>lshr</tt>' Instruction</a></li>
148 <li><a href="#i_ashr">'<tt>ashr</tt>' Instruction</a></li>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]149 <li><a href="#i_and">'<tt>and</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]150 <li><a href="#i_or">'<tt>or</tt>' Instruction</a></li>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]151 <li><a href="#i_xor">'<tt>xor</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]152 </ol>
153 </li>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]154 <li><a href="#vectorops">Vector Operations</a>
155 <ol>
156 <li><a href="#i_extractelement">'<tt>extractelement</tt>' Instruction</a></li>
157 <li><a href="#i_insertelement">'<tt>insertelement</tt>' Instruction</a></li>
158 <li><a href="#i_shufflevector">'<tt>shufflevector</tt>' Instruction</a></li>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]159 </ol>
160 </li>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]161 <li><a href="#aggregateops">Aggregate Operations</a>
162 <ol>
163 <li><a href="#i_extractvalue">'<tt>extractvalue</tt>' Instruction</a></li>
164 <li><a href="#i_insertvalue">'<tt>insertvalue</tt>' Instruction</a></li>
165 </ol>
166 </li>
Chris Lattner6ab66722006-08-15 00:45:58 +0000[diff] [blame]167 <li><a href="#memoryops">Memory Access and Addressing Operations</a>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]168 <ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]169 <li><a href="#i_alloca">'<tt>alloca</tt>' Instruction</a></li>
Robert Bocchino820bc75b2006-02-17 21:18:08 +0000[diff] [blame]170 <li><a href="#i_load">'<tt>load</tt>' Instruction</a></li>
171 <li><a href="#i_store">'<tt>store</tt>' Instruction</a></li>
172 <li><a href="#i_getelementptr">'<tt>getelementptr</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]173 </ol>
174 </li>
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]175 <li><a href="#convertops">Conversion Operations</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]176 <ol>
177 <li><a href="#i_trunc">'<tt>trunc .. to</tt>' Instruction</a></li>
178 <li><a href="#i_zext">'<tt>zext .. to</tt>' Instruction</a></li>
179 <li><a href="#i_sext">'<tt>sext .. to</tt>' Instruction</a></li>
180 <li><a href="#i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a></li>
181 <li><a href="#i_fpext">'<tt>fpext .. to</tt>' Instruction</a></li>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]182 <li><a href="#i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a></li>
183 <li><a href="#i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a></li>
184 <li><a href="#i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a></li>
185 <li><a href="#i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a></li>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]186 <li><a href="#i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a></li>
187 <li><a href="#i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a></li>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]188 <li><a href="#i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a></li>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]189 </ol>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]190 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]191 <li><a href="#otherops">Other Operations</a>
192 <ol>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]193 <li><a href="#i_icmp">'<tt>icmp</tt>' Instruction</a></li>
194 <li><a href="#i_fcmp">'<tt>fcmp</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]195 <li><a href="#i_phi">'<tt>phi</tt>' Instruction</a></li>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]196 <li><a href="#i_select">'<tt>select</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]197 <li><a href="#i_call">'<tt>call</tt>' Instruction</a></li>
Chris Lattner33337472006-01-13 23:26:01 +0000[diff] [blame]198 <li><a href="#i_va_arg">'<tt>va_arg</tt>' Instruction</a></li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]199 </ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]200 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]201 </ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]202 </li>
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]203 <li><a href="#intrinsics">Intrinsic Functions</a>
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]204 <ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]205 <li><a href="#int_varargs">Variable Argument Handling Intrinsics</a>
206 <ol>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]207 <li><a href="#int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a></li>
208 <li><a href="#int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a></li>
209 <li><a href="#int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]210 </ol>
211 </li>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]212 <li><a href="#int_gc">Accurate Garbage Collection Intrinsics</a>
213 <ol>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]214 <li><a href="#int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a></li>
215 <li><a href="#int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a></li>
216 <li><a href="#int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a></li>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]217 </ol>
218 </li>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]219 <li><a href="#int_codegen">Code Generator Intrinsics</a>
220 <ol>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]221 <li><a href="#int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a></li>
222 <li><a href="#int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a></li>
223 <li><a href="#int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a></li>
224 <li><a href="#int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a></li>
225 <li><a href="#int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a></li>
226 <li><a href="#int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a></li>
227 <li><a href="#int_readcyclecounter"><tt>llvm.readcyclecounter</tt>' Intrinsic</a></li>
John Criswellaa1c3c12004-04-09 16:43:20 +0000[diff] [blame]228 </ol>
229 </li>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]230 <li><a href="#int_libc">Standard C Library Intrinsics</a>
231 <ol>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]232 <li><a href="#int_memcpy">'<tt>llvm.memcpy.*</tt>' Intrinsic</a></li>
233 <li><a href="#int_memmove">'<tt>llvm.memmove.*</tt>' Intrinsic</a></li>
234 <li><a href="#int_memset">'<tt>llvm.memset.*</tt>' Intrinsic</a></li>
235 <li><a href="#int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a></li>
236 <li><a href="#int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a></li>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]237 <li><a href="#int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a></li>
238 <li><a href="#int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a></li>
239 <li><a href="#int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a></li>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]240 </ol>
241 </li>
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]242 <li><a href="#int_manip">Bit Manipulation Intrinsics</a>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]243 <ol>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]244 <li><a href="#int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a></li>
Chris Lattnerb748c672006-01-16 22:34:14 +0000[diff] [blame]245 <li><a href="#int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic </a></li>
246 <li><a href="#int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic </a></li>
247 <li><a href="#int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic </a></li>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]248 </ol>
249 </li>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]250 <li><a href="#int_overflow">Arithmetic with Overflow Intrinsics</a>
251 <ol>
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]252 <li><a href="#int_sadd_overflow">'<tt>llvm.sadd.with.overflow.*</tt> Intrinsics</a></li>
253 <li><a href="#int_uadd_overflow">'<tt>llvm.uadd.with.overflow.*</tt> Intrinsics</a></li>
254 <li><a href="#int_ssub_overflow">'<tt>llvm.ssub.with.overflow.*</tt> Intrinsics</a></li>
255 <li><a href="#int_usub_overflow">'<tt>llvm.usub.with.overflow.*</tt> Intrinsics</a></li>
256 <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]257 <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]258 </ol>
259 </li>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]260 <li><a href="#int_fp16">Half Precision Floating Point Intrinsics</a>
261 <ol>
Chris Lattnerbbd8bd32010-03-14 23:03:31 +0000[diff] [blame]262 <li><a href="#int_convert_to_fp16">'<tt>llvm.convert.to.fp16</tt>' Intrinsic</a></li>
263 <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]264 </ol>
265 </li>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]266 <li><a href="#int_debugger">Debugger intrinsics</a></li>
Jim Laskey2211f492007-03-14 19:31:19 +0000[diff] [blame]267 <li><a href="#int_eh">Exception Handling intrinsics</a></li>
Duncan Sands86e01192007-09-11 14:10:23 +0000[diff] [blame]268 <li><a href="#int_trampoline">Trampoline Intrinsic</a>
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]269 <ol>
270 <li><a href="#int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a></li>
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]271 </ol>
272 </li>
Bill Wendlingf85850f2008-11-18 22:10:53 +0000[diff] [blame]273 <li><a href="#int_atomics">Atomic intrinsics</a>
274 <ol>
275 <li><a href="#int_memory_barrier"><tt>llvm.memory_barrier</tt></a></li>
276 <li><a href="#int_atomic_cmp_swap"><tt>llvm.atomic.cmp.swap</tt></a></li>
277 <li><a href="#int_atomic_swap"><tt>llvm.atomic.swap</tt></a></li>
278 <li><a href="#int_atomic_load_add"><tt>llvm.atomic.load.add</tt></a></li>
279 <li><a href="#int_atomic_load_sub"><tt>llvm.atomic.load.sub</tt></a></li>
280 <li><a href="#int_atomic_load_and"><tt>llvm.atomic.load.and</tt></a></li>
281 <li><a href="#int_atomic_load_nand"><tt>llvm.atomic.load.nand</tt></a></li>
282 <li><a href="#int_atomic_load_or"><tt>llvm.atomic.load.or</tt></a></li>
283 <li><a href="#int_atomic_load_xor"><tt>llvm.atomic.load.xor</tt></a></li>
284 <li><a href="#int_atomic_load_max"><tt>llvm.atomic.load.max</tt></a></li>
285 <li><a href="#int_atomic_load_min"><tt>llvm.atomic.load.min</tt></a></li>
286 <li><a href="#int_atomic_load_umax"><tt>llvm.atomic.load.umax</tt></a></li>
287 <li><a href="#int_atomic_load_umin"><tt>llvm.atomic.load.umin</tt></a></li>
288 </ol>
289 </li>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]290 <li><a href="#int_memorymarkers">Memory Use Markers</a>
291 <ol>
292 <li><a href="#int_lifetime_start"><tt>llvm.lifetime.start</tt></a></li>
293 <li><a href="#int_lifetime_end"><tt>llvm.lifetime.end</tt></a></li>
294 <li><a href="#int_invariant_start"><tt>llvm.invariant.start</tt></a></li>
295 <li><a href="#int_invariant_end"><tt>llvm.invariant.end</tt></a></li>
296 </ol>
297 </li>
Reid Spencer5b2cb0f2007-07-20 19:59:11 +0000[diff] [blame]298 <li><a href="#int_general">General intrinsics</a>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]299 <ol>
Reid Spencer5b2cb0f2007-07-20 19:59:11 +0000[diff] [blame]300 <li><a href="#int_var_annotation">
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]301 '<tt>llvm.var.annotation</tt>' Intrinsic</a></li>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]302 <li><a href="#int_annotation">
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]303 '<tt>llvm.annotation.*</tt>' Intrinsic</a></li>
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]304 <li><a href="#int_trap">
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]305 '<tt>llvm.trap</tt>' Intrinsic</a></li>
306 <li><a href="#int_stackprotector">
307 '<tt>llvm.stackprotector</tt>' Intrinsic</a></li>
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]308 <li><a href="#int_objectsize">
309 '<tt>llvm.objectsize</tt>' Intrinsic</a></li>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]310 </ol>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]311 </li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]312 </ol>
313 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]314</ol>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]315
316<div class="doc_author">
317 <p>Written by <a href="mailto:sabre@nondot.org">Chris Lattner</a>
318 and <a href="mailto:vadve@cs.uiuc.edu">Vikram Adve</a></p>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]319</div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]320
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]321<!-- *********************************************************************** -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]322<div class="doc_section"> <a name="abstract">Abstract </a></div>
323<!-- *********************************************************************** -->
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]324
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]325<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]326
327<p>This document is a reference manual for the LLVM assembly language. LLVM is
328 a Static Single Assignment (SSA) based representation that provides type
329 safety, low-level operations, flexibility, and the capability of representing
330 'all' high-level languages cleanly. It is the common code representation
331 used throughout all phases of the LLVM compilation strategy.</p>
332
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]333</div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]334
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]335<!-- *********************************************************************** -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]336<div class="doc_section"> <a name="introduction">Introduction</a> </div>
337<!-- *********************************************************************** -->
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]338
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]339<div class="doc_text">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]340
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]341<p>The LLVM code representation is designed to be used in three different forms:
342 as an in-memory compiler IR, as an on-disk bitcode representation (suitable
343 for fast loading by a Just-In-Time compiler), and as a human readable
344 assembly language representation. This allows LLVM to provide a powerful
345 intermediate representation for efficient compiler transformations and
346 analysis, while providing a natural means to debug and visualize the
347 transformations. The three different forms of LLVM are all equivalent. This
348 document describes the human readable representation and notation.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]349
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]350<p>The LLVM representation aims to be light-weight and low-level while being
351 expressive, typed, and extensible at the same time. It aims to be a
352 "universal IR" of sorts, by being at a low enough level that high-level ideas
353 may be cleanly mapped to it (similar to how microprocessors are "universal
354 IR's", allowing many source languages to be mapped to them). By providing
355 type information, LLVM can be used as the target of optimizations: for
356 example, through pointer analysis, it can be proven that a C automatic
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]357 variable is never accessed outside of the current function, allowing it to
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]358 be promoted to a simple SSA value instead of a memory location.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]359
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]360</div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]361
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]362<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]363<div class="doc_subsubsection"> <a name="wellformed">Well-Formedness</a> </div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]364
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]365<div class="doc_text">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]366
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]367<p>It is important to note that this document describes 'well formed' LLVM
368 assembly language. There is a difference between what the parser accepts and
369 what is considered 'well formed'. For example, the following instruction is
370 syntactically okay, but not well formed:</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]371
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]372<div class="doc_code">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]373<pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]374%x = <a href="#i_add">add</a> i32 1, %x
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]375</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]376</div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]377
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]378<p>because the definition of <tt>%x</tt> does not dominate all of its uses. The
379 LLVM infrastructure provides a verification pass that may be used to verify
380 that an LLVM module is well formed. This pass is automatically run by the
381 parser after parsing input assembly and by the optimizer before it outputs
382 bitcode. The violations pointed out by the verifier pass indicate bugs in
383 transformation passes or input to the parser.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]384
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]385</div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]386
Chris Lattner87a3dbe2007-10-03 17:34:29 +0000[diff] [blame]387<!-- Describe the typesetting conventions here. -->
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]388
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]389<!-- *********************************************************************** -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]390<div class="doc_section"> <a name="identifiers">Identifiers</a> </div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]391<!-- *********************************************************************** -->
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]392
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]393<div class="doc_text">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]394
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]395<p>LLVM identifiers come in two basic types: global and local. Global
396 identifiers (functions, global variables) begin with the <tt>'@'</tt>
397 character. Local identifiers (register names, types) begin with
398 the <tt>'%'</tt> character. Additionally, there are three different formats
399 for identifiers, for different purposes:</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]400
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]401<ol>
Reid Spencerb23b65f2007-08-07 14:34:28 +0000[diff] [blame]402 <li>Named values are represented as a string of characters with their prefix.
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]403 For example, <tt>%foo</tt>, <tt>@DivisionByZero</tt>,
404 <tt>%a.really.long.identifier</tt>. The actual regular expression used is
405 '<tt>[%@][a-zA-Z$._][a-zA-Z$._0-9]*</tt>'. Identifiers which require
406 other characters in their names can be surrounded with quotes. Special
407 characters may be escaped using <tt>"\xx"</tt> where <tt>xx</tt> is the
408 ASCII code for the character in hexadecimal. In this way, any character
409 can be used in a name value, even quotes themselves.</li>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]410
Reid Spencerb23b65f2007-08-07 14:34:28 +0000[diff] [blame]411 <li>Unnamed values are represented as an unsigned numeric value with their
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]412 prefix. For example, <tt>%12</tt>, <tt>@2</tt>, <tt>%44</tt>.</li>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]413
Reid Spencer8f08d802004-12-09 18:02:53 +0000[diff] [blame]414 <li>Constants, which are described in a <a href="#constants">section about
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]415 constants</a>, below.</li>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]416</ol>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]417
Reid Spencerb23b65f2007-08-07 14:34:28 +0000[diff] [blame]418<p>LLVM requires that values start with a prefix for two reasons: Compilers
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]419 don't need to worry about name clashes with reserved words, and the set of
420 reserved words may be expanded in the future without penalty. Additionally,
421 unnamed identifiers allow a compiler to quickly come up with a temporary
422 variable without having to avoid symbol table conflicts.</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]423
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]424<p>Reserved words in LLVM are very similar to reserved words in other
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]425 languages. There are keywords for different opcodes
426 ('<tt><a href="#i_add">add</a></tt>',
427 '<tt><a href="#i_bitcast">bitcast</a></tt>',
428 '<tt><a href="#i_ret">ret</a></tt>', etc...), for primitive type names
429 ('<tt><a href="#t_void">void</a></tt>',
430 '<tt><a href="#t_primitive">i32</a></tt>', etc...), and others. These
431 reserved words cannot conflict with variable names, because none of them
432 start with a prefix character (<tt>'%'</tt> or <tt>'@'</tt>).</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]433
434<p>Here is an example of LLVM code to multiply the integer variable
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]435 '<tt>%X</tt>' by 8:</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]436
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]437<p>The easy way:</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]438
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]439<div class="doc_code">
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]440<pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]441%result = <a href="#i_mul">mul</a> i32 %X, 8
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]442</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]443</div>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]444
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]445<p>After strength reduction:</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]446
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]447<div class="doc_code">
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]448<pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]449%result = <a href="#i_shl">shl</a> i32 %X, i8 3
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]450</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]451</div>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]452
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]453<p>And the hard way:</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]454
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]455<div class="doc_code">
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]456<pre>
Gabor Greifbd0328f2009-10-28 13:05:07 +0000[diff] [blame]457%0 = <a href="#i_add">add</a> i32 %X, %X <i>; yields {i32}:%0</i>
458%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]459%result = <a href="#i_add">add</a> i32 %1, %1
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]460</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]461</div>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]462
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]463<p>This last way of multiplying <tt>%X</tt> by 8 illustrates several important
464 lexical features of LLVM:</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]465
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]466<ol>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]467 <li>Comments are delimited with a '<tt>;</tt>' and go until the end of
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]468 line.</li>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]469
470 <li>Unnamed temporaries are created when the result of a computation is not
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]471 assigned to a named value.</li>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]472
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]473 <li>Unnamed temporaries are numbered sequentially</li>
474</ol>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]475
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]476<p>It also shows a convention that we follow in this document. When
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]477 demonstrating instructions, we will follow an instruction with a comment that
478 defines the type and name of value produced. Comments are shown in italic
479 text.</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]480
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]481</div>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]482
483<!-- *********************************************************************** -->
484<div class="doc_section"> <a name="highlevel">High Level Structure</a> </div>
485<!-- *********************************************************************** -->
486
487<!-- ======================================================================= -->
488<div class="doc_subsection"> <a name="modulestructure">Module Structure</a>
489</div>
490
491<div class="doc_text">
492
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]493<p>LLVM programs are composed of "Module"s, each of which is a translation unit
494 of the input programs. Each module consists of functions, global variables,
495 and symbol table entries. Modules may be combined together with the LLVM
496 linker, which merges function (and global variable) definitions, resolves
497 forward declarations, and merges symbol table entries. Here is an example of
498 the "hello world" module:</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]499
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]500<div class="doc_code">
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]501<pre>
502<i>; Declare the string constant as a global constant.</i>
503<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]504
505<i>; External declaration of the puts function</i>
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]506<a href="#functionstructure">declare</a> i32 @puts(i8 *) <i>; i32(i8 *)* </i>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]507
508<i>; Definition of main function</i>
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]509define i32 @main() { <i>; i32()* </i>
510 <i>; Convert [13 x i8]* to i8 *...</i>
511 %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]512
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]513 <i>; Call puts function to write out the string to stdout.</i>
514 <a href="#i_call">call</a> i32 @puts(i8 * %cast210) <i>; i32</i>
Devang Pateld1a89692010-01-11 19:35:55 +0000[diff] [blame]515 <a href="#i_ret">ret</a> i32 0<br>}
516
517<i>; Named metadata</i>
518!1 = metadata !{i32 41}
519!foo = !{!1, null}
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]520</pre>
521</div>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]522
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]523<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]524 "<tt>.LC0</tt>", an external declaration of the "<tt>puts</tt>" function,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]525 a <a href="#functionstructure">function definition</a> for
Devang Pateld1a89692010-01-11 19:35:55 +0000[diff] [blame]526 "<tt>main</tt>" and <a href="#namedmetadatastructure">named metadata</a>
527 "<tt>foo"</tt>.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]528
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]529<p>In general, a module is made up of a list of global values, where both
530 functions and global variables are global values. Global values are
531 represented by a pointer to a memory location (in this case, a pointer to an
532 array of char, and a pointer to a function), and have one of the
533 following <a href="#linkage">linkage types</a>.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]534
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]535</div>
536
537<!-- ======================================================================= -->
538<div class="doc_subsection">
539 <a name="linkage">Linkage Types</a>
540</div>
541
542<div class="doc_text">
543
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]544<p>All Global Variables and Functions have one of the following types of
545 linkage:</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]546
547<dl>
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]548 <dt><tt><b><a name="linkage_private">private</a></b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]549 <dd>Global values with private linkage are only directly accessible by objects
550 in the current module. In particular, linking code into a module with an
551 private global value may cause the private to be renamed as necessary to
552 avoid collisions. Because the symbol is private to the module, all
553 references can be updated. This doesn't show up in any symbol table in the
554 object file.</dd>
Rafael Espindola6de96a12009-01-15 20:18:42 +0000[diff] [blame]555
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]556 <dt><tt><b><a name="linkage_linker_private">linker_private</a></b></tt></dt>
Bill Wendlinga3c6f6b2009-07-20 01:03:30 +0000[diff] [blame]557 <dd>Similar to private, but the symbol is passed through the assembler and
Chris Lattnere7f064e2009-08-24 04:32:16 +0000[diff] [blame]558 removed by the linker after evaluation. Note that (unlike private
559 symbols) linker_private symbols are subject to coalescing by the linker:
560 weak symbols get merged and redefinitions are rejected. However, unlike
561 normal strong symbols, they are removed by the linker from the final
562 linked image (executable or dynamic library).</dd>
Bill Wendlinga3c6f6b2009-07-20 01:03:30 +0000[diff] [blame]563
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]564 <dt><tt><b><a name="linkage_internal">internal</a></b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]565 <dd>Similar to private, but the value shows as a local symbol
566 (<tt>STB_LOCAL</tt> in the case of ELF) in the object file. This
567 corresponds to the notion of the '<tt>static</tt>' keyword in C.</dd>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]568
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]569 <dt><tt><b><a name="linkage_available_externally">available_externally</a></b></tt></dt>
Chris Lattner184f1be2009-04-13 05:44:34 +0000[diff] [blame]570 <dd>Globals with "<tt>available_externally</tt>" linkage are never emitted
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]571 into the object file corresponding to the LLVM module. They exist to
572 allow inlining and other optimizations to take place given knowledge of
573 the definition of the global, which is known to be somewhere outside the
574 module. Globals with <tt>available_externally</tt> linkage are allowed to
575 be discarded at will, and are otherwise the same as <tt>linkonce_odr</tt>.
576 This linkage type is only allowed on definitions, not declarations.</dd>
Chris Lattner184f1be2009-04-13 05:44:34 +0000[diff] [blame]577
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]578 <dt><tt><b><a name="linkage_linkonce">linkonce</a></b></tt></dt>
Chris Lattnere20b4702007-01-14 06:51:48 +0000[diff] [blame]579 <dd>Globals with "<tt>linkonce</tt>" linkage are merged with other globals of
Chris Lattner0de4caa2010-01-09 19:15:14 +0000[diff] [blame]580 the same name when linkage occurs. This can be used to implement
581 some forms of inline functions, templates, or other code which must be
582 generated in each translation unit that uses it, but where the body may
583 be overridden with a more definitive definition later. Unreferenced
584 <tt>linkonce</tt> globals are allowed to be discarded. Note that
585 <tt>linkonce</tt> linkage does not actually allow the optimizer to
586 inline the body of this function into callers because it doesn't know if
587 this definition of the function is the definitive definition within the
588 program or whether it will be overridden by a stronger definition.
589 To enable inlining and other optimizations, use "<tt>linkonce_odr</tt>"
590 linkage.</dd>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]591
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]592 <dt><tt><b><a name="linkage_weak">weak</a></b></tt></dt>
Chris Lattnerd0554882009-08-05 05:21:07 +0000[diff] [blame]593 <dd>"<tt>weak</tt>" linkage has the same merging semantics as
594 <tt>linkonce</tt> linkage, except that unreferenced globals with
595 <tt>weak</tt> linkage may not be discarded. This is used for globals that
596 are declared "weak" in C source code.</dd>
597
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]598 <dt><tt><b><a name="linkage_common">common</a></b></tt></dt>
Chris Lattnerd0554882009-08-05 05:21:07 +0000[diff] [blame]599 <dd>"<tt>common</tt>" linkage is most similar to "<tt>weak</tt>" linkage, but
600 they are used for tentative definitions in C, such as "<tt>int X;</tt>" at
601 global scope.
602 Symbols with "<tt>common</tt>" linkage are merged in the same way as
603 <tt>weak symbols</tt>, and they may not be deleted if unreferenced.
Chris Lattner0aff0b22009-08-05 05:41:44 +0000[diff] [blame]604 <tt>common</tt> symbols may not have an explicit section,
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]605 must have a zero initializer, and may not be marked '<a
Chris Lattner0aff0b22009-08-05 05:41:44 +0000[diff] [blame]606 href="#globalvars"><tt>constant</tt></a>'. Functions and aliases may not
607 have common linkage.</dd>
Chris Lattnerd0554882009-08-05 05:21:07 +0000[diff] [blame]608
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]609
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]610 <dt><tt><b><a name="linkage_appending">appending</a></b></tt></dt>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]611 <dd>"<tt>appending</tt>" linkage may only be applied to global variables of
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]612 pointer to array type. When two global variables with appending linkage
613 are linked together, the two global arrays are appended together. This is
614 the LLVM, typesafe, equivalent of having the system linker append together
615 "sections" with identical names when .o files are linked.</dd>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]616
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]617 <dt><tt><b><a name="linkage_externweak">extern_weak</a></b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]618 <dd>The semantics of this linkage follow the ELF object file model: the symbol
619 is weak until linked, if not linked, the symbol becomes null instead of
620 being an undefined reference.</dd>
Anton Korobeynikova0554d92007-01-12 19:20:47 +0000[diff] [blame]621
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]622 <dt><tt><b><a name="linkage_linkonce_odr">linkonce_odr</a></b></tt></dt>
623 <dt><tt><b><a name="linkage_weak_odr">weak_odr</a></b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]624 <dd>Some languages allow differing globals to be merged, such as two functions
625 with different semantics. Other languages, such as <tt>C++</tt>, ensure
626 that only equivalent globals are ever merged (the "one definition rule" -
627 "ODR"). Such languages can use the <tt>linkonce_odr</tt>
628 and <tt>weak_odr</tt> linkage types to indicate that the global will only
629 be merged with equivalent globals. These linkage types are otherwise the
630 same as their non-<tt>odr</tt> versions.</dd>
Duncan Sands12da8ce2009-03-07 15:45:40 +0000[diff] [blame]631
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]632 <dt><tt><b><a name="linkage_external">externally visible</a></b></tt>:</dt>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]633 <dd>If none of the above identifiers are used, the global is externally
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]634 visible, meaning that it participates in linkage and can be used to
635 resolve external symbol references.</dd>
Reid Spencer7972c472007-04-11 23:49:50 +0000[diff] [blame]636</dl>
Anton Korobeynikovd61d39e2006-09-14 18:23:27 +0000[diff] [blame]637
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]638<p>The next two types of linkage are targeted for Microsoft Windows platform
639 only. They are designed to support importing (exporting) symbols from (to)
640 DLLs (Dynamic Link Libraries).</p>
Anton Korobeynikovd61d39e2006-09-14 18:23:27 +0000[diff] [blame]641
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]642<dl>
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]643 <dt><tt><b><a name="linkage_dllimport">dllimport</a></b></tt></dt>
Anton Korobeynikovd61d39e2006-09-14 18:23:27 +0000[diff] [blame]644 <dd>"<tt>dllimport</tt>" linkage causes the compiler to reference a function
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]645 or variable via a global pointer to a pointer that is set up by the DLL
646 exporting the symbol. On Microsoft Windows targets, the pointer name is
647 formed by combining <code>__imp_</code> and the function or variable
648 name.</dd>
Anton Korobeynikovd61d39e2006-09-14 18:23:27 +0000[diff] [blame]649
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]650 <dt><tt><b><a name="linkage_dllexport">dllexport</a></b></tt></dt>
Anton Korobeynikovd61d39e2006-09-14 18:23:27 +0000[diff] [blame]651 <dd>"<tt>dllexport</tt>" linkage causes the compiler to provide a global
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]652 pointer to a pointer in a DLL, so that it can be referenced with the
653 <tt>dllimport</tt> attribute. On Microsoft Windows targets, the pointer
654 name is formed by combining <code>__imp_</code> and the function or
655 variable name.</dd>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]656</dl>
657
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]658<p>For example, since the "<tt>.LC0</tt>" variable is defined to be internal, if
659 another module defined a "<tt>.LC0</tt>" variable and was linked with this
660 one, one of the two would be renamed, preventing a collision. Since
661 "<tt>main</tt>" and "<tt>puts</tt>" are external (i.e., lacking any linkage
662 declarations), they are accessible outside of the current module.</p>
663
664<p>It is illegal for a function <i>declaration</i> to have any linkage type
665 other than "externally visible", <tt>dllimport</tt>
666 or <tt>extern_weak</tt>.</p>
667
Duncan Sands12da8ce2009-03-07 15:45:40 +0000[diff] [blame]668<p>Aliases can have only <tt>external</tt>, <tt>internal</tt>, <tt>weak</tt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]669 or <tt>weak_odr</tt> linkages.</p>
670
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]671</div>
672
673<!-- ======================================================================= -->
674<div class="doc_subsection">
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]675 <a name="callingconv">Calling Conventions</a>
676</div>
677
678<div class="doc_text">
679
680<p>LLVM <a href="#functionstructure">functions</a>, <a href="#i_call">calls</a>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]681 and <a href="#i_invoke">invokes</a> can all have an optional calling
682 convention specified for the call. The calling convention of any pair of
683 dynamic caller/callee must match, or the behavior of the program is
684 undefined. The following calling conventions are supported by LLVM, and more
685 may be added in the future:</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]686
687<dl>
688 <dt><b>"<tt>ccc</tt>" - The C calling convention</b>:</dt>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]689 <dd>This calling convention (the default if no other calling convention is
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]690 specified) matches the target C calling conventions. This calling
691 convention supports varargs function calls and tolerates some mismatch in
692 the declared prototype and implemented declaration of the function (as
693 does normal C).</dd>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]694
695 <dt><b>"<tt>fastcc</tt>" - The fast calling convention</b>:</dt>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]696 <dd>This calling convention attempts to make calls as fast as possible
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]697 (e.g. by passing things in registers). This calling convention allows the
698 target to use whatever tricks it wants to produce fast code for the
699 target, without having to conform to an externally specified ABI
Jeffrey Yasskinb8677462010-01-09 19:44:16 +0000[diff] [blame]700 (Application Binary Interface).
701 <a href="CodeGenerator.html#tailcallopt">Tail calls can only be optimized
Chris Lattnera179e4d2010-03-11 00:22:57 +0000[diff] [blame]702 when this or the GHC convention is used.</a> This calling convention
703 does not support varargs and requires the prototype of all callees to
704 exactly match the prototype of the function definition.</dd>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]705
706 <dt><b>"<tt>coldcc</tt>" - The cold calling convention</b>:</dt>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]707 <dd>This calling convention attempts to make code in the caller as efficient
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]708 as possible under the assumption that the call is not commonly executed.
709 As such, these calls often preserve all registers so that the call does
710 not break any live ranges in the caller side. This calling convention
711 does not support varargs and requires the prototype of all callees to
712 exactly match the prototype of the function definition.</dd>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]713
Chris Lattnera179e4d2010-03-11 00:22:57 +0000[diff] [blame]714 <dt><b>"<tt>cc <em>10</em></tt>" - GHC convention</b>:</dt>
715 <dd>This calling convention has been implemented specifically for use by the
716 <a href="http://www.haskell.org/ghc">Glasgow Haskell Compiler (GHC)</a>.
717 It passes everything in registers, going to extremes to achieve this by
718 disabling callee save registers. This calling convention should not be
719 used lightly but only for specific situations such as an alternative to
720 the <em>register pinning</em> performance technique often used when
721 implementing functional programming languages.At the moment only X86
722 supports this convention and it has the following limitations:
723 <ul>
724 <li>On <em>X86-32</em> only supports up to 4 bit type parameters. No
725 floating point types are supported.</li>
726 <li>On <em>X86-64</em> only supports up to 10 bit type parameters and
727 6 floating point parameters.</li>
728 </ul>
729 This calling convention supports
730 <a href="CodeGenerator.html#tailcallopt">tail call optimization</a> but
731 requires both the caller and callee are using it.
732 </dd>
733
Chris Lattner573f64e2005-05-07 01:46:40 +0000[diff] [blame]734 <dt><b>"<tt>cc &lt;<em>n</em>&gt;</tt>" - Numbered convention</b>:</dt>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]735 <dd>Any calling convention may be specified by number, allowing
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]736 target-specific calling conventions to be used. Target specific calling
737 conventions start at 64.</dd>
Chris Lattner573f64e2005-05-07 01:46:40 +0000[diff] [blame]738</dl>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]739
740<p>More calling conventions can be added/defined on an as-needed basis, to
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]741 support Pascal conventions or any other well-known target-independent
742 convention.</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]743
744</div>
745
746<!-- ======================================================================= -->
747<div class="doc_subsection">
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]748 <a name="visibility">Visibility Styles</a>
749</div>
750
751<div class="doc_text">
752
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]753<p>All Global Variables and Functions have one of the following visibility
754 styles:</p>
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]755
756<dl>
757 <dt><b>"<tt>default</tt>" - Default style</b>:</dt>
Chris Lattner67c37d12008-08-05 18:29:16 +0000[diff] [blame]758 <dd>On targets that use the ELF object file format, default visibility means
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]759 that the declaration is visible to other modules and, in shared libraries,
760 means that the declared entity may be overridden. On Darwin, default
761 visibility means that the declaration is visible to other modules. Default
762 visibility corresponds to "external linkage" in the language.</dd>
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]763
764 <dt><b>"<tt>hidden</tt>" - Hidden style</b>:</dt>
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]765 <dd>Two declarations of an object with hidden visibility refer to the same
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]766 object if they are in the same shared object. Usually, hidden visibility
767 indicates that the symbol will not be placed into the dynamic symbol
768 table, so no other module (executable or shared library) can reference it
769 directly.</dd>
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]770
Anton Korobeynikov39f3cff2007-04-29 18:35:00 +0000[diff] [blame]771 <dt><b>"<tt>protected</tt>" - Protected style</b>:</dt>
Anton Korobeynikov39f3cff2007-04-29 18:35:00 +0000[diff] [blame]772 <dd>On ELF, protected visibility indicates that the symbol will be placed in
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]773 the dynamic symbol table, but that references within the defining module
774 will bind to the local symbol. That is, the symbol cannot be overridden by
775 another module.</dd>
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]776</dl>
777
778</div>
779
780<!-- ======================================================================= -->
781<div class="doc_subsection">
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]782 <a name="namedtypes">Named Types</a>
783</div>
784
785<div class="doc_text">
786
787<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]788 it easier to read the IR and make the IR more condensed (particularly when
789 recursive types are involved). An example of a name specification is:</p>
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]790
791<div class="doc_code">
792<pre>
793%mytype = type { %mytype*, i32 }
794</pre>
795</div>
796
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]797<p>You may give a name to any <a href="#typesystem">type</a> except
798 "<a href="t_void">void</a>". Type name aliases may be used anywhere a type
799 is expected with the syntax "%mytype".</p>
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]800
801<p>Note that type names are aliases for the structural type that they indicate,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]802 and that you can therefore specify multiple names for the same type. This
803 often leads to confusing behavior when dumping out a .ll file. Since LLVM IR
804 uses structural typing, the name is not part of the type. When printing out
805 LLVM IR, the printer will pick <em>one name</em> to render all types of a
806 particular shape. This means that if you have code where two different
807 source types end up having the same LLVM type, that the dumper will sometimes
808 print the "wrong" or unexpected type. This is an important design point and
809 isn't going to change.</p>
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]810
811</div>
812
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]813<!-- ======================================================================= -->
814<div class="doc_subsection">
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]815 <a name="globalvars">Global Variables</a>
816</div>
817
818<div class="doc_text">
819
Chris Lattner5d5aede2005-02-12 19:30:21 +0000[diff] [blame]820<p>Global variables define regions of memory allocated at compilation time
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]821 instead of run-time. Global variables may optionally be initialized, may
822 have an explicit section to be placed in, and may have an optional explicit
823 alignment specified. A variable may be defined as "thread_local", which
824 means that it will not be shared by threads (each thread will have a
825 separated copy of the variable). A variable may be defined as a global
826 "constant," which indicates that the contents of the variable
827 will <b>never</b> be modified (enabling better optimization, allowing the
828 global data to be placed in the read-only section of an executable, etc).
829 Note that variables that need runtime initialization cannot be marked
830 "constant" as there is a store to the variable.</p>
Chris Lattner5d5aede2005-02-12 19:30:21 +0000[diff] [blame]831
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]832<p>LLVM explicitly allows <em>declarations</em> of global variables to be marked
833 constant, even if the final definition of the global is not. This capability
834 can be used to enable slightly better optimization of the program, but
835 requires the language definition to guarantee that optimizations based on the
836 'constantness' are valid for the translation units that do not include the
837 definition.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]838
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]839<p>As SSA values, global variables define pointer values that are in scope
840 (i.e. they dominate) all basic blocks in the program. Global variables
841 always define a pointer to their "content" type because they describe a
842 region of memory, and all memory objects in LLVM are accessed through
843 pointers.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]844
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]845<p>A global variable may be declared to reside in a target-specific numbered
846 address space. For targets that support them, address spaces may affect how
847 optimizations are performed and/or what target instructions are used to
848 access the variable. The default address space is zero. The address space
849 qualifier must precede any other attributes.</p>
Christopher Lamb308121c2007-12-11 09:31:00 +0000[diff] [blame]850
Chris Lattner662c8722005-11-12 00:45:07 +0000[diff] [blame]851<p>LLVM allows an explicit section to be specified for globals. If the target
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]852 supports it, it will emit globals to the section specified.</p>
Chris Lattner662c8722005-11-12 00:45:07 +0000[diff] [blame]853
Chris Lattner78e00bc2010-04-28 00:13:42 +0000[diff] [blame]854<p>An explicit alignment may be specified for a global, which must be a power
855 of 2. If not present, or if the alignment is set to zero, the alignment of
856 the global is set by the target to whatever it feels convenient. If an
857 explicit alignment is specified, the global is forced to have exactly that
Chris Lattner4bd85e42010-04-28 00:31:12 +0000[diff] [blame]858 alignment. Targets and optimizers are not allowed to over-align the global
859 if the global has an assigned section. In this case, the extra alignment
860 could be observable: for example, code could assume that the globals are
861 densely packed in their section and try to iterate over them as an array,
862 alignment padding would break this iteration.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]863
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]864<p>For example, the following defines a global in a numbered address space with
865 an initializer, section, and alignment:</p>
Chris Lattner5760c502007-01-14 00:27:09 +0000[diff] [blame]866
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]867<div class="doc_code">
Chris Lattner5760c502007-01-14 00:27:09 +0000[diff] [blame]868<pre>
Dan Gohmanaaa679b2009-01-11 00:40:00 +0000[diff] [blame]869@G = addrspace(5) constant float 1.0, section "foo", align 4
Chris Lattner5760c502007-01-14 00:27:09 +0000[diff] [blame]870</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]871</div>
Chris Lattner5760c502007-01-14 00:27:09 +0000[diff] [blame]872
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]873</div>
874
875
876<!-- ======================================================================= -->
877<div class="doc_subsection">
878 <a name="functionstructure">Functions</a>
879</div>
880
881<div class="doc_text">
882
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]883<p>LLVM function definitions consist of the "<tt>define</tt>" keyword, an
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]884 optional <a href="#linkage">linkage type</a>, an optional
885 <a href="#visibility">visibility style</a>, an optional
886 <a href="#callingconv">calling convention</a>, a return type, an optional
887 <a href="#paramattrs">parameter attribute</a> for the return type, a function
888 name, a (possibly empty) argument list (each with optional
889 <a href="#paramattrs">parameter attributes</a>), optional
890 <a href="#fnattrs">function attributes</a>, an optional section, an optional
891 alignment, an optional <a href="#gc">garbage collector name</a>, an opening
892 curly brace, a list of basic blocks, and a closing curly brace.</p>
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]893
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]894<p>LLVM function declarations consist of the "<tt>declare</tt>" keyword, an
895 optional <a href="#linkage">linkage type</a>, an optional
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]896 <a href="#visibility">visibility style</a>, an optional
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]897 <a href="#callingconv">calling convention</a>, a return type, an optional
898 <a href="#paramattrs">parameter attribute</a> for the return type, a function
899 name, a possibly empty list of arguments, an optional alignment, and an
900 optional <a href="#gc">garbage collector name</a>.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]901
Chris Lattner67c37d12008-08-05 18:29:16 +0000[diff] [blame]902<p>A function definition contains a list of basic blocks, forming the CFG
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]903 (Control Flow Graph) for the function. Each basic block may optionally start
904 with a label (giving the basic block a symbol table entry), contains a list
905 of instructions, and ends with a <a href="#terminators">terminator</a>
906 instruction (such as a branch or function return).</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]907
Chris Lattnera59fb102007-06-08 16:52:14 +0000[diff] [blame]908<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]909 executed on entrance to the function, and it is not allowed to have
910 predecessor basic blocks (i.e. there can not be any branches to the entry
911 block of a function). Because the block can have no predecessors, it also
912 cannot have any <a href="#i_phi">PHI nodes</a>.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]913
Chris Lattner662c8722005-11-12 00:45:07 +0000[diff] [blame]914<p>LLVM allows an explicit section to be specified for functions. If the target
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]915 supports it, it will emit functions to the section specified.</p>
Chris Lattner662c8722005-11-12 00:45:07 +0000[diff] [blame]916
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]917<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]918 the alignment is set to zero, the alignment of the function is set by the
919 target to whatever it feels convenient. If an explicit alignment is
920 specified, the function is forced to have at least that much alignment. All
921 alignments must be a power of 2.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]922
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]923<h5>Syntax:</h5>
Devang Patel02256232008-10-07 17:48:33 +0000[diff] [blame]924<div class="doc_code">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]925<pre>
Chris Lattner0ae02092008-10-13 16:55:18 +0000[diff] [blame]926define [<a href="#linkage">linkage</a>] [<a href="#visibility">visibility</a>]
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]927 [<a href="#callingconv">cconv</a>] [<a href="#paramattrs">ret attrs</a>]
928 &lt;ResultType&gt; @&lt;FunctionName&gt; ([argument list])
929 [<a href="#fnattrs">fn Attrs</a>] [section "name"] [align N]
930 [<a href="#gc">gc</a>] { ... }
931</pre>
Devang Patel02256232008-10-07 17:48:33 +0000[diff] [blame]932</div>
933
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]934</div>
935
Anton Korobeynikova97b6942007-04-25 14:27:10 +0000[diff] [blame]936<!-- ======================================================================= -->
937<div class="doc_subsection">
938 <a name="aliasstructure">Aliases</a>
939</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]940
Anton Korobeynikova97b6942007-04-25 14:27:10 +0000[diff] [blame]941<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]942
943<p>Aliases act as "second name" for the aliasee value (which can be either
944 function, global variable, another alias or bitcast of global value). Aliases
945 may have an optional <a href="#linkage">linkage type</a>, and an
946 optional <a href="#visibility">visibility style</a>.</p>
Anton Korobeynikova97b6942007-04-25 14:27:10 +0000[diff] [blame]947
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]948<h5>Syntax:</h5>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]949<div class="doc_code">
Bill Wendling2d8b9a82007-05-29 09:42:13 +0000[diff] [blame]950<pre>
Duncan Sands7e99a942008-09-12 20:48:21 +0000[diff] [blame]951@&lt;Name&gt; = alias [Linkage] [Visibility] &lt;AliaseeTy&gt; @&lt;Aliasee&gt;
Bill Wendling2d8b9a82007-05-29 09:42:13 +0000[diff] [blame]952</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]953</div>
Anton Korobeynikova97b6942007-04-25 14:27:10 +0000[diff] [blame]954
955</div>
956
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]957<!-- ======================================================================= -->
Devang Pateld1a89692010-01-11 19:35:55 +0000[diff] [blame]958<div class="doc_subsection">
959 <a name="namedmetadatastructure">Named Metadata</a>
960</div>
961
962<div class="doc_text">
963
Chris Lattnerc2f8f162010-01-15 21:50:19 +0000[diff] [blame]964<p>Named metadata is a collection of metadata. <a href="#metadata">Metadata
965 nodes</a> (but not metadata strings) and null are the only valid operands for
966 a named metadata.</p>
Devang Pateld1a89692010-01-11 19:35:55 +0000[diff] [blame]967
968<h5>Syntax:</h5>
969<div class="doc_code">
970<pre>
971!1 = metadata !{metadata !"one"}
972!name = !{null, !1}
973</pre>
974</div>
975
976</div>
977
978<!-- ======================================================================= -->
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]979<div class="doc_subsection"><a name="paramattrs">Parameter Attributes</a></div>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]980
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]981<div class="doc_text">
982
983<p>The return type and each parameter of a function type may have a set of
984 <i>parameter attributes</i> associated with them. Parameter attributes are
985 used to communicate additional information about the result or parameters of
986 a function. Parameter attributes are considered to be part of the function,
987 not of the function type, so functions with different parameter attributes
988 can have the same function type.</p>
989
990<p>Parameter attributes are simple keywords that follow the type specified. If
991 multiple parameter attributes are needed, they are space separated. For
992 example:</p>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]993
994<div class="doc_code">
995<pre>
Nick Lewyckydac78d82009-02-15 23:06:14 +0000[diff] [blame]996declare i32 @printf(i8* noalias nocapture, ...)
Chris Lattnerd2597d72008-10-04 18:33:34 +0000[diff] [blame]997declare i32 @atoi(i8 zeroext)
998declare signext i8 @returns_signed_char()
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]999</pre>
1000</div>
1001
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1002<p>Note that any attributes for the function result (<tt>nounwind</tt>,
1003 <tt>readonly</tt>) come immediately after the argument list.</p>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1004
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1005<p>Currently, only the following parameter attributes are defined:</p>
Chris Lattner5cee13f2008-01-11 06:20:47 +0000[diff] [blame]1006
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1007<dl>
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1008 <dt><tt><b>zeroext</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1009 <dd>This indicates to the code generator that the parameter or return value
1010 should be zero-extended to a 32-bit value by the caller (for a parameter)
1011 or the callee (for a return value).</dd>
Chris Lattner5cee13f2008-01-11 06:20:47 +0000[diff] [blame]1012
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1013 <dt><tt><b>signext</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 sign-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>inreg</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1019 <dd>This indicates that this parameter or return value should be treated in a
1020 special target-dependent fashion during while emitting code for a function
1021 call or return (usually, by putting it in a register as opposed to memory,
1022 though some targets use it to distinguish between two different kinds of
1023 registers). Use of this attribute is target-specific.</dd>
Chris Lattner5cee13f2008-01-11 06:20:47 +0000[diff] [blame]1024
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1025 <dt><tt><b><a name="byval">byval</a></b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1026 <dd>This indicates that the pointer parameter should really be passed by value
1027 to the function. The attribute implies that a hidden copy of the pointee
1028 is made between the caller and the callee, so the callee is unable to
1029 modify the value in the callee. This attribute is only valid on LLVM
1030 pointer arguments. It is generally used to pass structs and arrays by
1031 value, but is also valid on pointers to scalars. The copy is considered
1032 to belong to the caller not the callee (for example,
1033 <tt><a href="#readonly">readonly</a></tt> functions should not write to
1034 <tt>byval</tt> parameters). This is not a valid attribute for return
1035 values. The byval attribute also supports specifying an alignment with
1036 the align attribute. This has a target-specific effect on the code
1037 generator that usually indicates a desired alignment for the synthesized
1038 stack slot.</dd>
1039
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1040 <dt><tt><b>sret</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1041 <dd>This indicates that the pointer parameter specifies the address of a
1042 structure that is the return value of the function in the source program.
1043 This pointer must be guaranteed by the caller to be valid: loads and
1044 stores to the structure may be assumed by the callee to not to trap. This
1045 may only be applied to the first parameter. This is not a valid attribute
1046 for return values. </dd>
1047
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1048 <dt><tt><b>noalias</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1049 <dd>This indicates that the pointer does not alias any global or any other
1050 parameter. The caller is responsible for ensuring that this is the
1051 case. On a function return value, <tt>noalias</tt> additionally indicates
1052 that the pointer does not alias any other pointers visible to the
1053 caller. For further details, please see the discussion of the NoAlias
1054 response in
1055 <a href="http://llvm.org/docs/AliasAnalysis.html#MustMayNo">alias
1056 analysis</a>.</dd>
1057
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1058 <dt><tt><b>nocapture</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1059 <dd>This indicates that the callee does not make any copies of the pointer
1060 that outlive the callee itself. This is not a valid attribute for return
1061 values.</dd>
1062
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1063 <dt><tt><b>nest</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1064 <dd>This indicates that the pointer parameter can be excised using the
1065 <a href="#int_trampoline">trampoline intrinsics</a>. This is not a valid
1066 attribute for return values.</dd>
1067</dl>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1068
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1069</div>
1070
1071<!-- ======================================================================= -->
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]1072<div class="doc_subsection">
Gordon Henriksen71183b62007-12-10 03:18:06 +0000[diff] [blame]1073 <a name="gc">Garbage Collector Names</a>
1074</div>
1075
1076<div class="doc_text">
Gordon Henriksen71183b62007-12-10 03:18:06 +0000[diff] [blame]1077
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1078<p>Each function may specify a garbage collector name, which is simply a
1079 string:</p>
1080
1081<div class="doc_code">
1082<pre>
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1083define void @f() gc "name" { ... }
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1084</pre>
1085</div>
Gordon Henriksen71183b62007-12-10 03:18:06 +0000[diff] [blame]1086
1087<p>The compiler declares the supported values of <i>name</i>. Specifying a
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1088 collector which will cause the compiler to alter its output in order to
1089 support the named garbage collection algorithm.</p>
1090
Gordon Henriksen71183b62007-12-10 03:18:06 +0000[diff] [blame]1091</div>
1092
1093<!-- ======================================================================= -->
1094<div class="doc_subsection">
Devang Patel9eb525d2008-09-26 23:51:19 +0000[diff] [blame]1095 <a name="fnattrs">Function Attributes</a>
Devang Patelcaacdba2008-09-04 23:05:13 +0000[diff] [blame]1096</div>
1097
1098<div class="doc_text">
Devang Patel9eb525d2008-09-26 23:51:19 +0000[diff] [blame]1099
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1100<p>Function attributes are set to communicate additional information about a
1101 function. Function attributes are considered to be part of the function, not
1102 of the function type, so functions with different parameter attributes can
1103 have the same function type.</p>
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 simple keywords that follow the type specified. If
1106 multiple attributes are needed, they are space separated. For example:</p>
Devang Patelcaacdba2008-09-04 23:05:13 +0000[diff] [blame]1107
1108<div class="doc_code">
Bill Wendlingb175fa42008-09-07 10:26:33 +0000[diff] [blame]1109<pre>
Devang Patel9eb525d2008-09-26 23:51:19 +0000[diff] [blame]1110define void @f() noinline { ... }
1111define void @f() alwaysinline { ... }
1112define void @f() alwaysinline optsize { ... }
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1113define void @f() optsize { ... }
Bill Wendlingb175fa42008-09-07 10:26:33 +0000[diff] [blame]1114</pre>
Devang Patelcaacdba2008-09-04 23:05:13 +0000[diff] [blame]1115</div>
1116
Bill Wendlingb175fa42008-09-07 10:26:33 +0000[diff] [blame]1117<dl>
Charles Davisbe5557e2010-02-12 00:31:15 +0000[diff] [blame]1118 <dt><tt><b>alignstack(&lt;<em>n</em>&gt;)</b></tt></dt>
1119 <dd>This attribute indicates that, when emitting the prologue and epilogue,
1120 the backend should forcibly align the stack pointer. Specify the
1121 desired alignment, which must be a power of two, in parentheses.
1122
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1123 <dt><tt><b>alwaysinline</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1124 <dd>This attribute indicates that the inliner should attempt to inline this
1125 function into callers whenever possible, ignoring any active inlining size
1126 threshold for this caller.</dd>
Bill Wendlingb175fa42008-09-07 10:26:33 +0000[diff] [blame]1127
Jakob Stoklund Olesen74bb06c2010-02-06 01:16:28 +0000[diff] [blame]1128 <dt><tt><b>inlinehint</b></tt></dt>
1129 <dd>This attribute indicates that the source code contained a hint that inlining
1130 this function is desirable (such as the "inline" keyword in C/C++). It
1131 is just a hint; it imposes no requirements on the inliner.</dd>
1132
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1133 <dt><tt><b>noinline</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1134 <dd>This attribute indicates that the inliner should never inline this
1135 function in any situation. This attribute may not be used together with
1136 the <tt>alwaysinline</tt> attribute.</dd>
Devang Patel9eb525d2008-09-26 23:51:19 +0000[diff] [blame]1137
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1138 <dt><tt><b>optsize</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1139 <dd>This attribute suggests that optimization passes and code generator passes
1140 make choices that keep the code size of this function low, and otherwise
1141 do optimizations specifically to reduce code size.</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>noreturn</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1144 <dd>This function attribute indicates that the function never returns
1145 normally. This produces undefined behavior at runtime if the function
1146 ever does dynamically return.</dd>
Bill Wendlinga8130172008-11-13 01:02:51 +0000[diff] [blame]1147
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1148 <dt><tt><b>nounwind</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1149 <dd>This function attribute indicates that the function never returns with an
1150 unwind or exceptional control flow. If the function does unwind, its
1151 runtime behavior is undefined.</dd>
Bill Wendling0f5541e2008-11-26 19:07:40 +0000[diff] [blame]1152
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1153 <dt><tt><b>readnone</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1154 <dd>This attribute indicates that the function computes its result (or decides
1155 to unwind an exception) based strictly on its arguments, without
1156 dereferencing any pointer arguments or otherwise accessing any mutable
1157 state (e.g. memory, control registers, etc) visible to caller functions.
1158 It does not write through any pointer arguments
1159 (including <tt><a href="#byval">byval</a></tt> arguments) and never
1160 changes any state visible to callers. This means that it cannot unwind
1161 exceptions by calling the <tt>C++</tt> exception throwing methods, but
1162 could use the <tt>unwind</tt> instruction.</dd>
Devang Patel310fd4a2009-06-12 19:45:19 +0000[diff] [blame]1163
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1164 <dt><tt><b><a name="readonly">readonly</a></b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1165 <dd>This attribute indicates that the function does not write through any
1166 pointer arguments (including <tt><a href="#byval">byval</a></tt>
1167 arguments) or otherwise modify any state (e.g. memory, control registers,
1168 etc) visible to caller functions. It may dereference pointer arguments
1169 and read state that may be set in the caller. A readonly function always
1170 returns the same value (or unwinds an exception identically) when called
1171 with the same set of arguments and global state. It cannot unwind an
1172 exception by calling the <tt>C++</tt> exception throwing methods, but may
1173 use the <tt>unwind</tt> instruction.</dd>
Anton Korobeynikovc8ce7b082009-07-17 18:07:26 +0000[diff] [blame]1174
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1175 <dt><tt><b><a name="ssp">ssp</a></b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1176 <dd>This attribute indicates that the function should emit a stack smashing
1177 protector. It is in the form of a "canary"&mdash;a random value placed on
1178 the stack before the local variables that's checked upon return from the
1179 function to see if it has been overwritten. A heuristic is used to
1180 determine if a function needs stack protectors or not.<br>
1181<br>
1182 If a function that has an <tt>ssp</tt> attribute is inlined into a
1183 function that doesn't have an <tt>ssp</tt> attribute, then the resulting
1184 function will have an <tt>ssp</tt> attribute.</dd>
1185
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1186 <dt><tt><b>sspreq</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1187 <dd>This attribute indicates that the function should <em>always</em> emit a
1188 stack smashing protector. This overrides
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1189 the <tt><a href="#ssp">ssp</a></tt> function attribute.<br>
1190<br>
1191 If a function that has an <tt>sspreq</tt> attribute is inlined into a
1192 function that doesn't have an <tt>sspreq</tt> attribute or which has
1193 an <tt>ssp</tt> attribute, then the resulting function will have
1194 an <tt>sspreq</tt> attribute.</dd>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1195
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1196 <dt><tt><b>noredzone</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1197 <dd>This attribute indicates that the code generator should not use a red
1198 zone, even if the target-specific ABI normally permits it.</dd>
1199
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1200 <dt><tt><b>noimplicitfloat</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1201 <dd>This attributes disables implicit floating point instructions.</dd>
1202
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1203 <dt><tt><b>naked</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1204 <dd>This attribute disables prologue / epilogue emission for the function.
1205 This can have very system-specific consequences.</dd>
Bill Wendlingb175fa42008-09-07 10:26:33 +0000[diff] [blame]1206</dl>
1207
Devang Patelcaacdba2008-09-04 23:05:13 +0000[diff] [blame]1208</div>
1209
1210<!-- ======================================================================= -->
1211<div class="doc_subsection">
Chris Lattner93564892006-04-08 04:40:53 +0000[diff] [blame]1212 <a name="moduleasm">Module-Level Inline Assembly</a>
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]1213</div>
1214
1215<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1216
1217<p>Modules may contain "module-level inline asm" blocks, which corresponds to
1218 the GCC "file scope inline asm" blocks. These blocks are internally
1219 concatenated by LLVM and treated as a single unit, but may be separated in
1220 the <tt>.ll</tt> file if desired. The syntax is very simple:</p>
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]1221
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]1222<div class="doc_code">
1223<pre>
1224module asm "inline asm code goes here"
1225module asm "more can go here"
1226</pre>
1227</div>
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]1228
1229<p>The strings can contain any character by escaping non-printable characters.
1230 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]1231 for the number.</p>
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]1232
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1233<p>The inline asm code is simply printed to the machine code .s file when
1234 assembly code is generated.</p>
1235
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]1236</div>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]1237
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1238<!-- ======================================================================= -->
1239<div class="doc_subsection">
1240 <a name="datalayout">Data Layout</a>
1241</div>
1242
1243<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1244
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1245<p>A module may specify a target specific data layout string that specifies how
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1246 data is to be laid out in memory. The syntax for the data layout is
1247 simply:</p>
1248
1249<div class="doc_code">
1250<pre>
1251target datalayout = "<i>layout specification</i>"
1252</pre>
1253</div>
1254
1255<p>The <i>layout specification</i> consists of a list of specifications
1256 separated by the minus sign character ('-'). Each specification starts with
1257 a letter and may include other information after the letter to define some
1258 aspect of the data layout. The specifications accepted are as follows:</p>
1259
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1260<dl>
1261 <dt><tt>E</tt></dt>
1262 <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]1263 bits with the most significance have the lowest address location.</dd>
1264
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1265 <dt><tt>e</tt></dt>
Chris Lattner67c37d12008-08-05 18:29:16 +0000[diff] [blame]1266 <dd>Specifies that the target lays out data in little-endian form. That is,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1267 the bits with the least significance have the lowest address
1268 location.</dd>
1269
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1270 <dt><tt>p:<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]1271 <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]1272 <i>preferred</i> alignments. All sizes are in bits. Specifying
1273 the <i>pref</i> alignment is optional. If omitted, the
1274 preceding <tt>:</tt> should be omitted too.</dd>
1275
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1276 <dt><tt>i<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1277 <dd>This specifies the alignment for an integer type of a given bit
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1278 <i>size</i>. The value of <i>size</i> must be in the range [1,2^23).</dd>
1279
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1280 <dt><tt>v<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]1281 <dd>This specifies the alignment for a vector type of a given bit
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1282 <i>size</i>.</dd>
1283
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1284 <dt><tt>f<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]1285 <dd>This specifies the alignment for a floating point type of a given bit
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1286 <i>size</i>. The value of <i>size</i> must be either 32 (float) or 64
1287 (double).</dd>
1288
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1289 <dt><tt>a<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1290 <dd>This specifies the alignment for an aggregate type of a given bit
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1291 <i>size</i>.</dd>
1292
Daniel Dunbar7921a592009-06-08 22:17:53 +0000[diff] [blame]1293 <dt><tt>s<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1294 <dd>This specifies the alignment for a stack object of a given bit
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1295 <i>size</i>.</dd>
Chris Lattnera381eff2009-11-07 09:35:34 +0000[diff] [blame]1296
1297 <dt><tt>n<i>size1</i>:<i>size2</i>:<i>size3</i>...</tt></dt>
1298 <dd>This specifies a set of native integer widths for the target CPU
1299 in bits. For example, it might contain "n32" for 32-bit PowerPC,
1300 "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]1301 this set are considered to support most general arithmetic
Chris Lattnera381eff2009-11-07 09:35:34 +0000[diff] [blame]1302 operations efficiently.</dd>
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1303</dl>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1304
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1305<p>When constructing the data layout for a given target, LLVM starts with a
Dan Gohman61110ae2010-04-28 00:36:01 +0000[diff] [blame^]1306 default set of specifications which are then (possibly) overridden by the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1307 specifications in the <tt>datalayout</tt> keyword. The default specifications
1308 are given in this list:</p>
1309
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1310<ul>
1311 <li><tt>E</tt> - big endian</li>
Dan Gohman8ad777d2010-02-23 02:44:03 +0000[diff] [blame]1312 <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]1313 <li><tt>i1:8:8</tt> - i1 is 8-bit (byte) aligned</li>
1314 <li><tt>i8:8:8</tt> - i8 is 8-bit (byte) aligned</li>
1315 <li><tt>i16:16:16</tt> - i16 is 16-bit aligned</li>
1316 <li><tt>i32:32:32</tt> - i32 is 32-bit aligned</li>
Chris Lattner67c37d12008-08-05 18:29:16 +0000[diff] [blame]1317 <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]1318 alignment of 64-bits</li>
1319 <li><tt>f32:32:32</tt> - float is 32-bit aligned</li>
1320 <li><tt>f64:64:64</tt> - double is 64-bit aligned</li>
1321 <li><tt>v64:64:64</tt> - 64-bit vector is 64-bit aligned</li>
1322 <li><tt>v128:128:128</tt> - 128-bit vector is 128-bit aligned</li>
1323 <li><tt>a0:0:1</tt> - aggregates are 8-bit aligned</li>
Daniel Dunbar7921a592009-06-08 22:17:53 +0000[diff] [blame]1324 <li><tt>s0:64:64</tt> - stack objects are 64-bit aligned</li>
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1325</ul>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1326
1327<p>When LLVM is determining the alignment for a given type, it uses the
1328 following rules:</p>
1329
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1330<ol>
1331 <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]1332 specification is used.</li>
1333
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1334 <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]1335 smallest integer type that is larger than the bitwidth of the sought type
1336 is used. If none of the specifications are larger than the bitwidth then
1337 the the largest integer type is used. For example, given the default
1338 specifications above, the i7 type will use the alignment of i8 (next
1339 largest) while both i65 and i256 will use the alignment of i64 (largest
1340 specified).</li>
1341
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1342 <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]1343 largest vector type that is smaller than the sought vector type will be
1344 used as a fall back. This happens because &lt;128 x double&gt; can be
1345 implemented in terms of 64 &lt;2 x double&gt;, for example.</li>
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1346</ol>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1347
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1348</div>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]1349
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1350<!-- ======================================================================= -->
1351<div class="doc_subsection">
1352 <a name="pointeraliasing">Pointer Aliasing Rules</a>
1353</div>
1354
1355<div class="doc_text">
1356
Andreas Bolka8ae4e242009-07-29 00:02:05 +0000[diff] [blame]1357<p>Any memory access must be done through a pointer value associated
Andreas Bolkae39f0332009-07-27 20:37:10 +0000[diff] [blame]1358with an address range of the memory access, otherwise the behavior
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1359is undefined. Pointer values are associated with address ranges
1360according to the following rules:</p>
1361
1362<ul>
Andreas Bolka8ae4e242009-07-29 00:02:05 +0000[diff] [blame]1363 <li>A pointer value formed from a
1364 <tt><a href="#i_getelementptr">getelementptr</a></tt> instruction
1365 is associated with the addresses associated with the first operand
1366 of the <tt>getelementptr</tt>.</li>
1367 <li>An address of a global variable is associated with the address
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1368 range of the variable's storage.</li>
1369 <li>The result value of an allocation instruction is associated with
1370 the address range of the allocated storage.</li>
1371 <li>A null pointer in the default address-space is associated with
Andreas Bolka8ae4e242009-07-29 00:02:05 +0000[diff] [blame]1372 no address.</li>
1373 <li>A pointer value formed by an
1374 <tt><a href="#i_inttoptr">inttoptr</a></tt> is associated with all
1375 address ranges of all pointer values that contribute (directly or
1376 indirectly) to the computation of the pointer's value.</li>
1377 <li>The result value of a
1378 <tt><a href="#i_bitcast">bitcast</a></tt> is associated with all
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1379 addresses associated with the operand of the <tt>bitcast</tt>.</li>
1380 <li>An integer constant other than zero or a pointer value returned
1381 from a function not defined within LLVM may be associated with address
1382 ranges allocated through mechanisms other than those provided by
Andreas Bolka8ae4e242009-07-29 00:02:05 +0000[diff] [blame]1383 LLVM. Such ranges shall not overlap with any ranges of addresses
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1384 allocated by mechanisms provided by LLVM.</li>
1385 </ul>
1386
1387<p>LLVM IR does not associate types with memory. The result type of a
Andreas Bolka8ae4e242009-07-29 00:02:05 +0000[diff] [blame]1388<tt><a href="#i_load">load</a></tt> merely indicates the size and
1389alignment of the memory from which to load, as well as the
1390interpretation of the value. The first operand of a
1391<tt><a href="#i_store">store</a></tt> similarly only indicates the size
1392and alignment of the store.</p>
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1393
1394<p>Consequently, type-based alias analysis, aka TBAA, aka
1395<tt>-fstrict-aliasing</tt>, is not applicable to general unadorned
1396LLVM IR. <a href="#metadata">Metadata</a> may be used to encode
1397additional information which specialized optimization passes may use
1398to implement type-based alias analysis.</p>
1399
1400</div>
1401
Jeffrey Yasskin5d284ae2010-04-26 21:21:24 +0000[diff] [blame]1402<!-- ======================================================================= -->
1403<div class="doc_subsection">
1404 <a name="volatile">Volatile Memory Accesses</a>
1405</div>
1406
1407<div class="doc_text">
1408
1409<p>Certain memory accesses, such as <a href="#i_load"><tt>load</tt></a>s, <a
1410href="#i_store"><tt>store</tt></a>s, and <a
1411href="#int_memcpy"><tt>llvm.memcpy</tt></a>s may be marked <tt>volatile</tt>.
1412The optimizers must not change the number of volatile operations or change their
1413order of execution relative to other volatile operations. The optimizers
1414<i>may</i> change the order of volatile operations relative to non-volatile
1415operations. This is not Java's "volatile" and has no cross-thread
1416synchronization behavior.</p>
1417
1418</div>
1419
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1420<!-- *********************************************************************** -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1421<div class="doc_section"> <a name="typesystem">Type System</a> </div>
1422<!-- *********************************************************************** -->
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]1423
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1424<div class="doc_text">
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]1425
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1426<p>The LLVM type system is one of the most important features of the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1427 intermediate representation. Being typed enables a number of optimizations
1428 to be performed on the intermediate representation directly, without having
1429 to do extra analyses on the side before the transformation. A strong type
1430 system makes it easier to read the generated code and enables novel analyses
1431 and transformations that are not feasible to perform on normal three address
1432 code representations.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]1433
1434</div>
1435
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1436<!-- ======================================================================= -->
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1437<div class="doc_subsection"> <a name="t_classifications">Type
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1438Classifications</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1439
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1440<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1441
1442<p>The types fall into a few useful classifications:</p>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]1443
1444<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1445 <tbody>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1446 <tr><th>Classification</th><th>Types</th></tr>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1447 <tr>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1448 <td><a href="#t_integer">integer</a></td>
Reid Spencer138249b2007-05-16 18:44:01 +0000[diff] [blame]1449 <td><tt>i1, i2, i3, ... i8, ... i16, ... i32, ... i64, ... </tt></td>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1450 </tr>
1451 <tr>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1452 <td><a href="#t_floating">floating point</a></td>
1453 <td><tt>float, double, x86_fp80, fp128, ppc_fp128</tt></td>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1454 </tr>
1455 <tr>
1456 <td><a name="t_firstclass">first class</a></td>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1457 <td><a href="#t_integer">integer</a>,
1458 <a href="#t_floating">floating point</a>,
1459 <a href="#t_pointer">pointer</a>,
Dan Gohman08783a882008-06-18 18:42:13 +0000[diff] [blame]1460 <a href="#t_vector">vector</a>,
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]1461 <a href="#t_struct">structure</a>,
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]1462 <a href="#t_union">union</a>,
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]1463 <a href="#t_array">array</a>,
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1464 <a href="#t_label">label</a>,
1465 <a href="#t_metadata">metadata</a>.
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1466 </td>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1467 </tr>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1468 <tr>
1469 <td><a href="#t_primitive">primitive</a></td>
1470 <td><a href="#t_label">label</a>,
1471 <a href="#t_void">void</a>,
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1472 <a href="#t_floating">floating point</a>,
1473 <a href="#t_metadata">metadata</a>.</td>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1474 </tr>
1475 <tr>
1476 <td><a href="#t_derived">derived</a></td>
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]1477 <td><a href="#t_array">array</a>,
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1478 <a href="#t_function">function</a>,
1479 <a href="#t_pointer">pointer</a>,
1480 <a href="#t_struct">structure</a>,
1481 <a href="#t_pstruct">packed structure</a>,
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]1482 <a href="#t_union">union</a>,
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1483 <a href="#t_vector">vector</a>,
1484 <a href="#t_opaque">opaque</a>.
Dan Gohman93bf60d2008-10-14 16:32:04 +0000[diff] [blame]1485 </td>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1486 </tr>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1487 </tbody>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1488</table>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]1489
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1490<p>The <a href="#t_firstclass">first class</a> types are perhaps the most
1491 important. Values of these types are the only ones which can be produced by
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]1492 instructions.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1493
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1494</div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1495
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1496<!-- ======================================================================= -->
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1497<div class="doc_subsection"> <a name="t_primitive">Primitive Types</a> </div>
Chris Lattner43542b32008-01-04 04:34:14 +0000[diff] [blame]1498
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1499<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1500
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1501<p>The primitive types are the fundamental building blocks of the LLVM
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1502 system.</p>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1503
Chris Lattner43542b32008-01-04 04:34:14 +0000[diff] [blame]1504</div>
1505
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1506<!-- _______________________________________________________________________ -->
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]1507<div class="doc_subsubsection"> <a name="t_integer">Integer Type</a> </div>
1508
1509<div class="doc_text">
1510
1511<h5>Overview:</h5>
1512<p>The integer type is a very simple type that simply specifies an arbitrary
1513 bit width for the integer type desired. Any bit width from 1 bit to
1514 2<sup>23</sup>-1 (about 8 million) can be specified.</p>
1515
1516<h5>Syntax:</h5>
1517<pre>
1518 iN
1519</pre>
1520
1521<p>The number of bits the integer will occupy is specified by the <tt>N</tt>
1522 value.</p>
1523
1524<h5>Examples:</h5>
1525<table class="layout">
1526 <tr class="layout">
1527 <td class="left"><tt>i1</tt></td>
1528 <td class="left">a single-bit integer.</td>
1529 </tr>
1530 <tr class="layout">
1531 <td class="left"><tt>i32</tt></td>
1532 <td class="left">a 32-bit integer.</td>
1533 </tr>
1534 <tr class="layout">
1535 <td class="left"><tt>i1942652</tt></td>
1536 <td class="left">a really big integer of over 1 million bits.</td>
1537 </tr>
1538</table>
1539
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]1540</div>
1541
1542<!-- _______________________________________________________________________ -->
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1543<div class="doc_subsubsection"> <a name="t_floating">Floating Point Types</a> </div>
1544
1545<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1546
1547<table>
1548 <tbody>
1549 <tr><th>Type</th><th>Description</th></tr>
1550 <tr><td><tt>float</tt></td><td>32-bit floating point value</td></tr>
1551 <tr><td><tt>double</tt></td><td>64-bit floating point value</td></tr>
1552 <tr><td><tt>fp128</tt></td><td>128-bit floating point value (112-bit mantissa)</td></tr>
1553 <tr><td><tt>x86_fp80</tt></td><td>80-bit floating point value (X87)</td></tr>
1554 <tr><td><tt>ppc_fp128</tt></td><td>128-bit floating point value (two 64-bits)</td></tr>
1555 </tbody>
1556</table>
1557
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1558</div>
1559
1560<!-- _______________________________________________________________________ -->
1561<div class="doc_subsubsection"> <a name="t_void">Void Type</a> </div>
1562
1563<div class="doc_text">
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1564
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1565<h5>Overview:</h5>
1566<p>The void type does not represent any value and has no size.</p>
1567
1568<h5>Syntax:</h5>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1569<pre>
1570 void
1571</pre>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1572
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1573</div>
1574
1575<!-- _______________________________________________________________________ -->
1576<div class="doc_subsubsection"> <a name="t_label">Label Type</a> </div>
1577
1578<div class="doc_text">
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1579
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1580<h5>Overview:</h5>
1581<p>The label type represents code labels.</p>
1582
1583<h5>Syntax:</h5>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1584<pre>
1585 label
1586</pre>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1587
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1588</div>
1589
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1590<!-- _______________________________________________________________________ -->
1591<div class="doc_subsubsection"> <a name="t_metadata">Metadata Type</a> </div>
1592
1593<div class="doc_text">
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1594
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1595<h5>Overview:</h5>
Nick Lewycky93e06a52009-09-27 23:27:42 +0000[diff] [blame]1596<p>The metadata type represents embedded metadata. No derived types may be
1597 created from metadata except for <a href="#t_function">function</a>
1598 arguments.
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1599
1600<h5>Syntax:</h5>
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1601<pre>
1602 metadata
1603</pre>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1604
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1605</div>
1606
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1607
1608<!-- ======================================================================= -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1609<div class="doc_subsection"> <a name="t_derived">Derived Types</a> </div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1610
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1611<div class="doc_text">
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1612
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1613<p>The real power in LLVM comes from the derived types in the system. This is
1614 what allows a programmer to represent arrays, functions, pointers, and other
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]1615 useful types. Each of these types contain one or more element types which
1616 may be a primitive type, or another derived type. For example, it is
1617 possible to have a two dimensional array, using an array as the element type
1618 of another array.</p>
Dan Gohman142ccc02009-01-24 15:58:40 +0000[diff] [blame]1619
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]1620
1621</div>
1622
1623<!-- _______________________________________________________________________ -->
1624<div class="doc_subsubsection"> <a name="t_aggregate">Aggregate Types</a> </div>
1625
1626<div class="doc_text">
1627
1628<p>Aggregate Types are a subset of derived types that can contain multiple
1629 member types. <a href="#t_array">Arrays</a>,
1630 <a href="#t_struct">structs</a>, <a href="#t_vector">vectors</a> and
1631 <a href="#t_union">unions</a> are aggregate types.</p>
1632
1633</div>
1634
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]1635</div>
Reid Spencer138249b2007-05-16 18:44:01 +0000[diff] [blame]1636
1637<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1638<div class="doc_subsubsection"> <a name="t_array">Array Type</a> </div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1639
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1640<div class="doc_text">
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1641
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1642<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1643<p>The array type is a very simple derived type that arranges elements
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1644 sequentially in memory. The array type requires a size (number of elements)
1645 and an underlying data type.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1646
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]1647<h5>Syntax:</h5>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1648<pre>
1649 [&lt;# elements&gt; x &lt;elementtype&gt;]
1650</pre>
1651
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1652<p>The number of elements is a constant integer value; <tt>elementtype</tt> may
1653 be any type with a size.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1654
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]1655<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1656<table class="layout">
1657 <tr class="layout">
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]1658 <td class="left"><tt>[40 x i32]</tt></td>
1659 <td class="left">Array of 40 32-bit integer values.</td>
1660 </tr>
1661 <tr class="layout">
1662 <td class="left"><tt>[41 x i32]</tt></td>
1663 <td class="left">Array of 41 32-bit integer values.</td>
1664 </tr>
1665 <tr class="layout">
1666 <td class="left"><tt>[4 x i8]</tt></td>
1667 <td class="left">Array of 4 8-bit integer values.</td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1668 </tr>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1669</table>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1670<p>Here are some examples of multidimensional arrays:</p>
1671<table class="layout">
1672 <tr class="layout">
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]1673 <td class="left"><tt>[3 x [4 x i32]]</tt></td>
1674 <td class="left">3x4 array of 32-bit integer values.</td>
1675 </tr>
1676 <tr class="layout">
1677 <td class="left"><tt>[12 x [10 x float]]</tt></td>
1678 <td class="left">12x10 array of single precision floating point values.</td>
1679 </tr>
1680 <tr class="layout">
1681 <td class="left"><tt>[2 x [3 x [4 x i16]]]</tt></td>
1682 <td class="left">2x3x4 array of 16-bit integer values.</td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1683 </tr>
1684</table>
Chris Lattnerc0ad71e2005-06-24 17:22:57 +0000[diff] [blame]1685
Dan Gohmanc74bc282009-11-09 19:01:53 +0000[diff] [blame]1686<p>There is no restriction on indexing beyond the end of the array implied by
1687 a static type (though there are restrictions on indexing beyond the bounds
1688 of an allocated object in some cases). This means that single-dimension
1689 'variable sized array' addressing can be implemented in LLVM with a zero
1690 length array type. An implementation of 'pascal style arrays' in LLVM could
1691 use the type "<tt>{ i32, [0 x float]}</tt>", for example.</p>
Chris Lattnerc0ad71e2005-06-24 17:22:57 +0000[diff] [blame]1692
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1693</div>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1694
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1695<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1696<div class="doc_subsubsection"> <a name="t_function">Function Type</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1697
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1698<div class="doc_text">
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]1699
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1700<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1701<p>The function type can be thought of as a function signature. It consists of
1702 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]1703 function type is a scalar type, a void type, a struct type, or a union
1704 type. If the return type is a struct type then all struct elements must be
1705 of first class types, and the struct must have at least one element.</p>
Devang Pateld6cff512008-03-10 20:49:15 +0000[diff] [blame]1706
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1707<h5>Syntax:</h5>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]1708<pre>
Nick Lewycky14d1ccc2009-09-27 07:55:32 +0000[diff] [blame]1709 &lt;returntype&gt; (&lt;parameter list&gt;)
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]1710</pre>
1711
John Criswell4c0cf7f2005-10-24 16:17:18 +0000[diff] [blame]1712<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]1713 specifiers. Optionally, the parameter list may include a type <tt>...</tt>,
1714 which indicates that the function takes a variable number of arguments.
1715 Variable argument functions can access their arguments with
1716 the <a href="#int_varargs">variable argument handling intrinsic</a>
Chris Lattner47f2a832010-03-02 06:36:51 +0000[diff] [blame]1717 functions. '<tt>&lt;returntype&gt;</tt>' is any type except
Nick Lewycky93e06a52009-09-27 23:27:42 +0000[diff] [blame]1718 <a href="#t_label">label</a>.</p>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]1719
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1720<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1721<table class="layout">
1722 <tr class="layout">
Reid Spencer58c08712006-12-31 07:18:34 +0000[diff] [blame]1723 <td class="left"><tt>i32 (i32)</tt></td>
1724 <td class="left">function taking an <tt>i32</tt>, returning an <tt>i32</tt>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1725 </td>
Reid Spencer58c08712006-12-31 07:18:34 +0000[diff] [blame]1726 </tr><tr class="layout">
Chris Lattner47f2a832010-03-02 06:36:51 +0000[diff] [blame]1727 <td class="left"><tt>float&nbsp;(i16,&nbsp;i32&nbsp;*)&nbsp;*
Reid Spencer655dcc62006-12-31 07:20:23 +0000[diff] [blame]1728 </tt></td>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]1729 <td class="left"><a href="#t_pointer">Pointer</a> to a function that takes
Chris Lattner47f2a832010-03-02 06:36:51 +0000[diff] [blame]1730 an <tt>i16</tt> and a <a href="#t_pointer">pointer</a> to <tt>i32</tt>,
1731 returning <tt>float</tt>.
Reid Spencer58c08712006-12-31 07:18:34 +0000[diff] [blame]1732 </td>
1733 </tr><tr class="layout">
1734 <td class="left"><tt>i32 (i8*, ...)</tt></td>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]1735 <td class="left">A vararg function that takes at least one
1736 <a href="#t_pointer">pointer</a> to <tt>i8 </tt> (char in C),
1737 which returns an integer. This is the signature for <tt>printf</tt> in
Reid Spencer58c08712006-12-31 07:18:34 +0000[diff] [blame]1738 LLVM.
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1739 </td>
Devang Patele3dfc1c2008-03-24 05:35:41 +0000[diff] [blame]1740 </tr><tr class="layout">
1741 <td class="left"><tt>{i32, i32} (i32)</tt></td>
Nick Lewycky14d1ccc2009-09-27 07:55:32 +0000[diff] [blame]1742 <td class="left">A function taking an <tt>i32</tt>, returning a
1743 <a href="#t_struct">structure</a> containing two <tt>i32</tt> values
Devang Patele3dfc1c2008-03-24 05:35:41 +0000[diff] [blame]1744 </td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1745 </tr>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1746</table>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]1747
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1748</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1749
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1750<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1751<div class="doc_subsubsection"> <a name="t_struct">Structure Type</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1752
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1753<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1754
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1755<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1756<p>The structure type is used to represent a collection of data members together
1757 in memory. The packing of the field types is defined to match the ABI of the
1758 underlying processor. The elements of a structure may be any type that has a
1759 size.</p>
1760
Jeffrey Yasskinf991bbb2010-01-11 19:19:26 +0000[diff] [blame]1761<p>Structures in memory are accessed using '<tt><a href="#i_load">load</a></tt>'
1762 and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a field
1763 with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.
1764 Structures in registers are accessed using the
1765 '<tt><a href="#i_extractvalue">extractvalue</a></tt>' and
1766 '<tt><a href="#i_insertvalue">insertvalue</a></tt>' instructions.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1767<h5>Syntax:</h5>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1768<pre>
1769 { &lt;type list&gt; }
1770</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1771
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1772<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1773<table class="layout">
1774 <tr class="layout">
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]1775 <td class="left"><tt>{ i32, i32, i32 }</tt></td>
1776 <td class="left">A triple of three <tt>i32</tt> values</td>
1777 </tr><tr class="layout">
1778 <td class="left"><tt>{&nbsp;float,&nbsp;i32&nbsp;(i32)&nbsp;*&nbsp;}</tt></td>
1779 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1780 second element is a <a href="#t_pointer">pointer</a> to a
1781 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1782 an <tt>i32</tt>.</td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1783 </tr>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1784</table>
Dan Gohman142ccc02009-01-24 15:58:40 +0000[diff] [blame]1785
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1786</div>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1787
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1788<!-- _______________________________________________________________________ -->
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]1789<div class="doc_subsubsection"> <a name="t_pstruct">Packed Structure Type</a>
1790</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1791
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]1792<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1793
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]1794<h5>Overview:</h5>
1795<p>The packed structure type is used to represent a collection of data members
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1796 together in memory. There is no padding between fields. Further, the
1797 alignment of a packed structure is 1 byte. The elements of a packed
1798 structure may be any type that has a size.</p>
1799
1800<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt> and
1801 '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a field with
1802 the '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
1803
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]1804<h5>Syntax:</h5>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1805<pre>
1806 &lt; { &lt;type list&gt; } &gt;
1807</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1808
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]1809<h5>Examples:</h5>
1810<table class="layout">
1811 <tr class="layout">
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]1812 <td class="left"><tt>&lt; { i32, i32, i32 } &gt;</tt></td>
1813 <td class="left">A triple of three <tt>i32</tt> values</td>
1814 </tr><tr class="layout">
Bill Wendlingb175fa42008-09-07 10:26:33 +0000[diff] [blame]1815 <td class="left">
1816<tt>&lt;&nbsp;{&nbsp;float,&nbsp;i32&nbsp;(i32)*&nbsp;}&nbsp;&gt;</tt></td>
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]1817 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1818 second element is a <a href="#t_pointer">pointer</a> to a
1819 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1820 an <tt>i32</tt>.</td>
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]1821 </tr>
1822</table>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1823
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]1824</div>
1825
1826<!-- _______________________________________________________________________ -->
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]1827<div class="doc_subsubsection"> <a name="t_union">Union Type</a> </div>
1828
1829<div class="doc_text">
1830
1831<h5>Overview:</h5>
1832<p>A union type describes an object with size and alignment suitable for
1833 an object of any one of a given set of types (also known as an "untagged"
1834 union). It is similar in concept and usage to a
1835 <a href="#t_struct">struct</a>, except that all members of the union
1836 have an offset of zero. The elements of a union may be any type that has a
1837 size. Unions must have at least one member - empty unions are not allowed.
1838 </p>
1839
1840<p>The size of the union as a whole will be the size of its largest member,
1841 and the alignment requirements of the union as a whole will be the largest
1842 alignment requirement of any member.</p>
1843
Dan Gohman1ad14992010-02-25 16:51:31 +0000[diff] [blame]1844<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]1845 '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a field with
1846 the '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.
1847 Since all members are at offset zero, the getelementptr instruction does
1848 not affect the address, only the type of the resulting pointer.</p>
1849
1850<h5>Syntax:</h5>
1851<pre>
1852 union { &lt;type list&gt; }
1853</pre>
1854
1855<h5>Examples:</h5>
1856<table class="layout">
1857 <tr class="layout">
1858 <td class="left"><tt>union { i32, i32*, float }</tt></td>
1859 <td class="left">A union of three types: an <tt>i32</tt>, a pointer to
1860 an <tt>i32</tt>, and a <tt>float</tt>.</td>
1861 </tr><tr class="layout">
1862 <td class="left">
1863 <tt>union {&nbsp;float,&nbsp;i32&nbsp;(i32)&nbsp;*&nbsp;}</tt></td>
1864 <td class="left">A union, where the first element is a <tt>float</tt> and the
1865 second element is a <a href="#t_pointer">pointer</a> to a
1866 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1867 an <tt>i32</tt>.</td>
1868 </tr>
1869</table>
1870
1871</div>
1872
1873<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1874<div class="doc_subsubsection"> <a name="t_pointer">Pointer Type</a> </div>
Chris Lattner4a67c912009-02-08 19:53:29 +0000[diff] [blame]1875
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1876<div class="doc_text">
1877
1878<h5>Overview:</h5>
Dan Gohman88481112010-02-25 16:50:07 +0000[diff] [blame]1879<p>The pointer type is used to specify memory locations.
1880 Pointers are commonly used to reference objects in memory.</p>
1881
1882<p>Pointer types may have an optional address space attribute defining the
1883 numbered address space where the pointed-to object resides. The default
1884 address space is number zero. The semantics of non-zero address
1885 spaces are target-specific.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1886
1887<p>Note that LLVM does not permit pointers to void (<tt>void*</tt>) nor does it
1888 permit pointers to labels (<tt>label*</tt>). Use <tt>i8*</tt> instead.</p>
Chris Lattner4a67c912009-02-08 19:53:29 +0000[diff] [blame]1889
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]1890<h5>Syntax:</h5>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1891<pre>
1892 &lt;type&gt; *
1893</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1894
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]1895<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1896<table class="layout">
1897 <tr class="layout">
Dan Gohman623806e2009-01-04 23:44:43 +0000[diff] [blame]1898 <td class="left"><tt>[4 x i32]*</tt></td>
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]1899 <td class="left">A <a href="#t_pointer">pointer</a> to <a
1900 href="#t_array">array</a> of four <tt>i32</tt> values.</td>
1901 </tr>
1902 <tr class="layout">
1903 <td class="left"><tt>i32 (i32 *) *</tt></td>
1904 <td class="left"> A <a href="#t_pointer">pointer</a> to a <a
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1905 href="#t_function">function</a> that takes an <tt>i32*</tt>, returning an
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]1906 <tt>i32</tt>.</td>
1907 </tr>
1908 <tr class="layout">
1909 <td class="left"><tt>i32 addrspace(5)*</tt></td>
1910 <td class="left">A <a href="#t_pointer">pointer</a> to an <tt>i32</tt> value
1911 that resides in address space #5.</td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1912 </tr>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1913</table>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1914
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1915</div>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1916
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1917<!-- _______________________________________________________________________ -->
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]1918<div class="doc_subsubsection"> <a name="t_vector">Vector Type</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1919
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1920<div class="doc_text">
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1921
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1922<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1923<p>A vector type is a simple derived type that represents a vector of elements.
1924 Vector types are used when multiple primitive data are operated in parallel
1925 using a single instruction (SIMD). A vector type requires a size (number of
Duncan Sands31c0e0e2009-11-27 13:38:03 +0000[diff] [blame]1926 elements) and an underlying primitive data type. Vector types are considered
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1927 <a href="#t_firstclass">first class</a>.</p>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1928
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1929<h5>Syntax:</h5>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1930<pre>
1931 &lt; &lt;# elements&gt; x &lt;elementtype&gt; &gt;
1932</pre>
1933
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1934<p>The number of elements is a constant integer value; elementtype may be any
1935 integer or floating point type.</p>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1936
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1937<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1938<table class="layout">
1939 <tr class="layout">
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]1940 <td class="left"><tt>&lt;4 x i32&gt;</tt></td>
1941 <td class="left">Vector of 4 32-bit integer values.</td>
1942 </tr>
1943 <tr class="layout">
1944 <td class="left"><tt>&lt;8 x float&gt;</tt></td>
1945 <td class="left">Vector of 8 32-bit floating-point values.</td>
1946 </tr>
1947 <tr class="layout">
1948 <td class="left"><tt>&lt;2 x i64&gt;</tt></td>
1949 <td class="left">Vector of 2 64-bit integer values.</td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1950 </tr>
1951</table>
Dan Gohman142ccc02009-01-24 15:58:40 +0000[diff] [blame]1952
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1953</div>
1954
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1955<!-- _______________________________________________________________________ -->
1956<div class="doc_subsubsection"> <a name="t_opaque">Opaque Type</a> </div>
1957<div class="doc_text">
1958
1959<h5>Overview:</h5>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1960<p>Opaque types are used to represent unknown types in the system. This
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1961 corresponds (for example) to the C notion of a forward declared structure
1962 type. In LLVM, opaque types can eventually be resolved to any type (not just
1963 a structure type).</p>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1964
1965<h5>Syntax:</h5>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1966<pre>
1967 opaque
1968</pre>
1969
1970<h5>Examples:</h5>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1971<table class="layout">
1972 <tr class="layout">
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]1973 <td class="left"><tt>opaque</tt></td>
1974 <td class="left">An opaque type.</td>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1975 </tr>
1976</table>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1977
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1978</div>
1979
Chris Lattnercf7a5842009-02-02 07:32:36 +0000[diff] [blame]1980<!-- ======================================================================= -->
1981<div class="doc_subsection">
1982 <a name="t_uprefs">Type Up-references</a>
1983</div>
1984
1985<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1986
Chris Lattnercf7a5842009-02-02 07:32:36 +0000[diff] [blame]1987<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1988<p>An "up reference" allows you to refer to a lexically enclosing type without
1989 requiring it to have a name. For instance, a structure declaration may
1990 contain a pointer to any of the types it is lexically a member of. Example
1991 of up references (with their equivalent as named type declarations)
1992 include:</p>
Chris Lattnercf7a5842009-02-02 07:32:36 +0000[diff] [blame]1993
1994<pre>
Chris Lattnerbf1d5452009-02-09 10:00:56 +0000[diff] [blame]1995 { \2 * } %x = type { %x* }
Chris Lattnercf7a5842009-02-02 07:32:36 +0000[diff] [blame]1996 { \2 }* %y = type { %y }*
1997 \1* %z = type %z*
1998</pre>
1999
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2000<p>An up reference is needed by the asmprinter for printing out cyclic types
2001 when there is no declared name for a type in the cycle. Because the
2002 asmprinter does not want to print out an infinite type string, it needs a
2003 syntax to handle recursive types that have no names (all names are optional
2004 in llvm IR).</p>
Chris Lattnercf7a5842009-02-02 07:32:36 +0000[diff] [blame]2005
2006<h5>Syntax:</h5>
2007<pre>
2008 \&lt;level&gt;
2009</pre>
2010
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2011<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]2012
2013<h5>Examples:</h5>
Chris Lattnercf7a5842009-02-02 07:32:36 +0000[diff] [blame]2014<table class="layout">
2015 <tr class="layout">
2016 <td class="left"><tt>\1*</tt></td>
2017 <td class="left">Self-referential pointer.</td>
2018 </tr>
2019 <tr class="layout">
2020 <td class="left"><tt>{ { \3*, i8 }, i32 }</tt></td>
2021 <td class="left">Recursive structure where the upref refers to the out-most
2022 structure.</td>
2023 </tr>
2024</table>
Chris Lattnercf7a5842009-02-02 07:32:36 +0000[diff] [blame]2025
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2026</div>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]2027
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2028<!-- *********************************************************************** -->
2029<div class="doc_section"> <a name="constants">Constants</a> </div>
2030<!-- *********************************************************************** -->
2031
2032<div class="doc_text">
2033
2034<p>LLVM has several different basic types of constants. This section describes
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2035 them all and their syntax.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2036
2037</div>
2038
2039<!-- ======================================================================= -->
Reid Spencer8f08d802004-12-09 18:02:53 +0000[diff] [blame]2040<div class="doc_subsection"><a name="simpleconstants">Simple Constants</a></div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2041
2042<div class="doc_text">
2043
2044<dl>
2045 <dt><b>Boolean constants</b></dt>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2046 <dd>The two strings '<tt>true</tt>' and '<tt>false</tt>' are both valid
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]2047 constants of the <tt><a href="#t_integer">i1</a></tt> type.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2048
2049 <dt><b>Integer constants</b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2050 <dd>Standard integers (such as '4') are constants of
2051 the <a href="#t_integer">integer</a> type. Negative numbers may be used
2052 with integer types.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2053
2054 <dt><b>Floating point constants</b></dt>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2055 <dd>Floating point constants use standard decimal notation (e.g. 123.421),
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2056 exponential notation (e.g. 1.23421e+2), or a more precise hexadecimal
2057 notation (see below). The assembler requires the exact decimal value of a
2058 floating-point constant. For example, the assembler accepts 1.25 but
2059 rejects 1.3 because 1.3 is a repeating decimal in binary. Floating point
2060 constants must have a <a href="#t_floating">floating point</a> type. </dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2061
2062 <dt><b>Null pointer constants</b></dt>
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]2063 <dd>The identifier '<tt>null</tt>' is recognized as a null pointer constant
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2064 and must be of <a href="#t_pointer">pointer type</a>.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2065</dl>
2066
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2067<p>The one non-intuitive notation for constants is the hexadecimal form of
2068 floating point constants. For example, the form '<tt>double
2069 0x432ff973cafa8000</tt>' is equivalent to (but harder to read than)
2070 '<tt>double 4.5e+15</tt>'. The only time hexadecimal floating point
2071 constants are required (and the only time that they are generated by the
2072 disassembler) is when a floating point constant must be emitted but it cannot
2073 be represented as a decimal floating point number in a reasonable number of
2074 digits. For example, NaN's, infinities, and other special values are
2075 represented in their IEEE hexadecimal format so that assembly and disassembly
2076 do not cause any bits to change in the constants.</p>
2077
Dale Johannesencd4a3012009-02-11 22:14:51 +0000[diff] [blame]2078<p>When using the hexadecimal form, constants of types float and double are
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2079 represented using the 16-digit form shown above (which matches the IEEE754
2080 representation for double); float values must, however, be exactly
2081 representable as IEE754 single precision. Hexadecimal format is always used
2082 for long double, and there are three forms of long double. The 80-bit format
2083 used by x86 is represented as <tt>0xK</tt> followed by 20 hexadecimal digits.
2084 The 128-bit format used by PowerPC (two adjacent doubles) is represented
2085 by <tt>0xM</tt> followed by 32 hexadecimal digits. The IEEE 128-bit format
2086 is represented by <tt>0xL</tt> followed by 32 hexadecimal digits; no
2087 currently supported target uses this format. Long doubles will only work if
2088 they match the long double format on your target. All hexadecimal formats
2089 are big-endian (sign bit at the left).</p>
2090
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2091</div>
2092
2093<!-- ======================================================================= -->
Chris Lattner361bfcd2009-02-28 18:32:25 +0000[diff] [blame]2094<div class="doc_subsection">
Bill Wendling972b7202009-07-20 02:32:41 +0000[diff] [blame]2095<a name="aggregateconstants"></a> <!-- old anchor -->
2096<a name="complexconstants">Complex Constants</a>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2097</div>
2098
2099<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2100
Chris Lattner361bfcd2009-02-28 18:32:25 +0000[diff] [blame]2101<p>Complex constants are a (potentially recursive) combination of simple
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2102 constants and smaller complex constants.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2103
2104<dl>
2105 <dt><b>Structure constants</b></dt>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2106 <dd>Structure constants are represented with notation similar to structure
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2107 type definitions (a comma separated list of elements, surrounded by braces
2108 (<tt>{}</tt>)). For example: "<tt>{ i32 4, float 17.0, i32* @G }</tt>",
2109 where "<tt>@G</tt>" is declared as "<tt>@G = external global i32</tt>".
2110 Structure constants must have <a href="#t_struct">structure type</a>, and
2111 the number and types of elements must match those specified by the
2112 type.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2113
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]2114 <dt><b>Union constants</b></dt>
2115 <dd>Union constants are represented with notation similar to a structure with
2116 a single element - that is, a single typed element surrounded
2117 by braces (<tt>{}</tt>)). For example: "<tt>{ i32 4 }</tt>". The
2118 <a href="#t_union">union type</a> can be initialized with a single-element
2119 struct as long as the type of the struct element matches the type of
2120 one of the union members.</dd>
2121
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2122 <dt><b>Array constants</b></dt>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2123 <dd>Array constants are represented with notation similar to array type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2124 definitions (a comma separated list of elements, surrounded by square
2125 brackets (<tt>[]</tt>)). For example: "<tt>[ i32 42, i32 11, i32 74
2126 ]</tt>". Array constants must have <a href="#t_array">array type</a>, and
2127 the number and types of elements must match those specified by the
2128 type.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2129
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]2130 <dt><b>Vector constants</b></dt>
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]2131 <dd>Vector constants are represented with notation similar to vector type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2132 definitions (a comma separated list of elements, surrounded by
2133 less-than/greater-than's (<tt>&lt;&gt;</tt>)). For example: "<tt>&lt; i32
2134 42, i32 11, i32 74, i32 100 &gt;</tt>". Vector constants must
2135 have <a href="#t_vector">vector type</a>, and the number and types of
2136 elements must match those specified by the type.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2137
2138 <dt><b>Zero initialization</b></dt>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2139 <dd>The string '<tt>zeroinitializer</tt>' can be used to zero initialize a
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]2140 value to zero of <em>any</em> type, including scalar and
2141 <a href="#t_aggregate">aggregate</a> types.
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2142 This is often used to avoid having to print large zero initializers
2143 (e.g. for large arrays) and is always exactly equivalent to using explicit
2144 zero initializers.</dd>
Nick Lewycky49f89192009-04-04 07:22:01 +0000[diff] [blame]2145
2146 <dt><b>Metadata node</b></dt>
Nick Lewycky8e2c4f42009-05-30 16:08:30 +0000[diff] [blame]2147 <dd>A metadata node is a structure-like constant with
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2148 <a href="#t_metadata">metadata type</a>. For example: "<tt>metadata !{
2149 i32 0, metadata !"test" }</tt>". Unlike other constants that are meant to
2150 be interpreted as part of the instruction stream, metadata is a place to
2151 attach additional information such as debug info.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2152</dl>
2153
2154</div>
2155
2156<!-- ======================================================================= -->
2157<div class="doc_subsection">
2158 <a name="globalconstants">Global Variable and Function Addresses</a>
2159</div>
2160
2161<div class="doc_text">
2162
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2163<p>The addresses of <a href="#globalvars">global variables</a>
2164 and <a href="#functionstructure">functions</a> are always implicitly valid
2165 (link-time) constants. These constants are explicitly referenced when
2166 the <a href="#identifiers">identifier for the global</a> is used and always
2167 have <a href="#t_pointer">pointer</a> type. For example, the following is a
2168 legal LLVM file:</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2169
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2170<div class="doc_code">
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2171<pre>
Chris Lattner00538a12007-06-06 18:28:13 +0000[diff] [blame]2172@X = global i32 17
2173@Y = global i32 42
2174@Z = global [2 x i32*] [ i32* @X, i32* @Y ]
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2175</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2176</div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2177
2178</div>
2179
2180<!-- ======================================================================= -->
Reid Spencer641f5c92004-12-09 18:13:12 +0000[diff] [blame]2181<div class="doc_subsection"><a name="undefvalues">Undefined Values</a></div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2182<div class="doc_text">
2183
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2184<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]2185 indicates that the user of the value may receive an unspecified bit-pattern.
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2186 Undefined values may be of any type (other than label or void) and be used
2187 anywhere a constant is permitted.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2188
Chris Lattner92ada5d2009-09-11 01:49:31 +0000[diff] [blame]2189<p>Undefined values are useful because they indicate to the compiler that the
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2190 program is well defined no matter what value is used. This gives the
2191 compiler more freedom to optimize. Here are some examples of (potentially
2192 surprising) transformations that are valid (in pseudo IR):</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2193
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2194
2195<div class="doc_code">
2196<pre>
2197 %A = add %X, undef
2198 %B = sub %X, undef
2199 %C = xor %X, undef
2200Safe:
2201 %A = undef
2202 %B = undef
2203 %C = undef
2204</pre>
2205</div>
2206
2207<p>This is safe because all of the output bits are affected by the undef bits.
2208Any output bit can have a zero or one depending on the input bits.</p>
2209
2210<div class="doc_code">
2211<pre>
2212 %A = or %X, undef
2213 %B = and %X, undef
2214Safe:
2215 %A = -1
2216 %B = 0
2217Unsafe:
2218 %A = undef
2219 %B = undef
2220</pre>
2221</div>
2222
2223<p>These logical operations have bits that are not always affected by the input.
2224For example, if "%X" has a zero bit, then the output of the 'and' operation will
2225always be a zero, no matter what the corresponding bit from the undef is. As
Chris Lattner92ada5d2009-09-11 01:49:31 +0000[diff] [blame]2226such, 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]2227However, it is safe to assume that all bits of the undef could be 0, and
2228optimize the and to 0. Likewise, it is safe to assume that all the bits of
2229the 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]2230-1.</p>
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2231
2232<div class="doc_code">
2233<pre>
2234 %A = select undef, %X, %Y
2235 %B = select undef, 42, %Y
2236 %C = select %X, %Y, undef
2237Safe:
2238 %A = %X (or %Y)
2239 %B = 42 (or %Y)
2240 %C = %Y
2241Unsafe:
2242 %A = undef
2243 %B = undef
2244 %C = undef
2245</pre>
2246</div>
2247
2248<p>This set of examples show that undefined select (and conditional branch)
2249conditions can go "either way" but they have to come from one of the two
2250operands. In the %A example, if %X and %Y were both known to have a clear low
2251bit, then %A would have to have a cleared low bit. However, in the %C example,
2252the optimizer is allowed to assume that the undef operand could be the same as
2253%Y, allowing the whole select to be eliminated.</p>
2254
2255
2256<div class="doc_code">
2257<pre>
2258 %A = xor undef, undef
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]2259
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2260 %B = undef
2261 %C = xor %B, %B
2262
2263 %D = undef
2264 %E = icmp lt %D, 4
2265 %F = icmp gte %D, 4
2266
2267Safe:
2268 %A = undef
2269 %B = undef
2270 %C = undef
2271 %D = undef
2272 %E = undef
2273 %F = undef
2274</pre>
2275</div>
2276
2277<p>This example points out that two undef operands are not necessarily the same.
2278This can be surprising to people (and also matches C semantics) where they
2279assume that "X^X" is always zero, even if X is undef. This isn't true for a
2280number of reasons, but the short answer is that an undef "variable" can
2281arbitrarily change its value over its "live range". This is true because the
2282"variable" doesn't actually <em>have a live range</em>. Instead, the value is
2283logically read from arbitrary registers that happen to be around when needed,
Benjamin Kramer0f420382009-10-12 14:46:08 +0000[diff] [blame]2284so the value is not necessarily consistent over time. In fact, %A and %C need
Chris Lattner6760e542009-09-08 15:13:16 +0000[diff] [blame]2285to have the same semantics or the core LLVM "replace all uses with" concept
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2286would not hold.</p>
Chris Lattnera34a7182009-09-07 23:33:52 +0000[diff] [blame]2287
2288<div class="doc_code">
2289<pre>
2290 %A = fdiv undef, %X
2291 %B = fdiv %X, undef
2292Safe:
2293 %A = undef
2294b: unreachable
2295</pre>
2296</div>
2297
2298<p>These examples show the crucial difference between an <em>undefined
2299value</em> and <em>undefined behavior</em>. An undefined value (like undef) is
2300allowed to have an arbitrary bit-pattern. This means that the %A operation
2301can be constant folded to undef because the undef could be an SNaN, and fdiv is
2302not (currently) defined on SNaN's. However, in the second example, we can make
2303a more aggressive assumption: because the undef is allowed to be an arbitrary
2304value, 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]2305has <em>undefined behavior</em>, we are allowed to assume that the operation
Chris Lattnera34a7182009-09-07 23:33:52 +0000[diff] [blame]2306does not execute at all. This allows us to delete the divide and all code after
2307it: since the undefined operation "can't happen", the optimizer can assume that
2308it occurs in dead code.
2309</p>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]2310
Chris Lattnera34a7182009-09-07 23:33:52 +0000[diff] [blame]2311<div class="doc_code">
2312<pre>
2313a: store undef -> %X
2314b: store %X -> undef
2315Safe:
2316a: &lt;deleted&gt;
2317b: unreachable
2318</pre>
2319</div>
2320
2321<p>These examples reiterate the fdiv example: a store "of" an undefined value
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]2322can be assumed to not have any effect: we can assume that the value is
Chris Lattnera34a7182009-09-07 23:33:52 +0000[diff] [blame]2323overwritten with bits that happen to match what was already there. However, a
2324store "to" an undefined location could clobber arbitrary memory, therefore, it
2325has undefined behavior.</p>
2326
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2327</div>
2328
2329<!-- ======================================================================= -->
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]2330<div class="doc_subsection"><a name="trapvalues">Trap Values</a></div>
2331<div class="doc_text">
2332
Dan Gohmanb2a709b2010-04-26 20:21:21 +0000[diff] [blame]2333<p>Trap values are similar to <a href="#undefvalues">undef values</a>, however
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]2334 instead of representing an unspecified bit pattern, they represent the
2335 fact that an instruction or constant expression which cannot evoke side
2336 effects has nevertheless detected a condition which results in undefined
Dan Gohmanb2a709b2010-04-26 20:21:21 +0000[diff] [blame]2337 behavior.</p>
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]2338
Dan Gohmanb8b85c12010-04-26 23:36:52 +0000[diff] [blame]2339<p>Any value other than a non-intrinsic call, invoke, or phi with a trap
2340 operand has trap as its result value. Any instruction with
2341 a trap operand which may have side effects emits those side effects as
2342 if it had an undef operand instead. If the side effects are externally
2343 visible, the behavior is undefined.</p>
2344
2345<p>Trap values may be stored to memory; a load from memory including any
2346 part of a trap value results in a (full) trap value.</p>
2347
2348<p>For example:</p>
2349
2350<!-- FIXME: In the case of multiple threads, this only applies to loads from
2351 the same thread as the store, or loads which are sequenced after the
2352 store by synchronization. -->
2353
2354<div class="doc_code">
2355<pre>
2356%trap = sub nuw i32 0, 1 ; Results in a trap value.
2357%still_trap = and i32 %trap, 0 ; Whereas (and i32 undef, 0) would return 0.
2358%trap_yet_again = getelementptr i32* @h, i32 %still_trap
2359store i32 0, i32* %trap_yet_again ; undefined behavior
2360
2361volatile store i32 %trap, i32* @g ; External observation; undefined behavior.
2362%trap2 = load i32* @g ; Returns a trap value, not just undef.
2363%narrowaddr = bitcast i32* @g to i16*
2364%wideaddr = bitcast i32* @g to i64*
2365%trap3 = load 16* %narrowaddr ; Returns a trap value
2366%trap4 = load i64* %widaddr ; Returns a trap value, not partial trap.
2367</pre>
2368</div>
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]2369
Dan Gohman48a25882010-04-26 20:54:53 +0000[diff] [blame]2370<p>If a <a href="#i_br"><tt>br</tt></a> or
2371 <a href="#i_switch"><tt>switch</tt></a> instruction has a trap value
2372 operand, all non-phi non-void instructions which control-depend on it
Dan Gohmanb8b85c12010-04-26 23:36:52 +0000[diff] [blame]2373 have trap as their result value. A <a href="#i_phi"><tt>phi</tt></a>
2374 node with an incoming value associated with a control edge which is
2375 control-dependent on it has trap as its result value when control is
2376 transferred from that block. If any instruction which control-depends
2377 on the <tt>br</tt> or <tt>switch</tt> invokes externally visible side
2378 effects, the behavior of the program is undefined. For example:</p>
Dan Gohman48a25882010-04-26 20:54:53 +0000[diff] [blame]2379
2380<!-- FIXME: What about exceptions thrown from control-dependent instrs? -->
2381
Dan Gohmanb8b85c12010-04-26 23:36:52 +0000[diff] [blame]2382<div class="doc_code">
2383<pre>
2384entry:
2385 %trap = sub nuw i32 0, 1 ; Results in a trap value.
2386 %cmp = icmp i32 slt %trap, 0 ; Still trap.
2387 %br i1 %cmp, %true, %end ; Branch to either destination.
2388
2389true:
2390 volatile store i32 0, i32* @g ; Externally visible side effects
2391 ; control-dependent on %cmp.
2392 ; Undefined behavior.
2393 br label %end
2394
2395end:
2396 %p = phi i32 [ 0, %entry ], [ 1, %true ]
2397 ; Both edges into this PHI are
2398 ; control-dependent on %cmp, so this
2399 ; results in a trap value.
2400
2401 volatile store i32 0, i32* @g ; %end is control-equivalent to %entry
2402 ; so this is defined (ignoring earlier
2403 ; undefined behavior in this example).
2404
2405</pre>
2406</div>
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]2407
2408<p>There is currently no way of representing a trap constant in the IR; they
2409 only exist when produced by certain instructions, such as an
2410 <a href="#i_add"><tt>add</tt></a> with the <tt>nsw</tt> flag
2411 set, when overflow occurs.</p>
2412
2413</div>
2414
2415<!-- ======================================================================= -->
Chris Lattner2bfd3202009-10-27 21:19:13 +0000[diff] [blame]2416<div class="doc_subsection"><a name="blockaddress">Addresses of Basic
2417 Blocks</a></div>
Chris Lattnere4801f72009-10-27 21:01:34 +0000[diff] [blame]2418<div class="doc_text">
2419
Chris Lattneraa99c942009-11-01 01:27:45 +0000[diff] [blame]2420<p><b><tt>blockaddress(@function, %block)</tt></b></p>
Chris Lattnere4801f72009-10-27 21:01:34 +0000[diff] [blame]2421
2422<p>The '<tt>blockaddress</tt>' constant computes the address of the specified
Chris Lattner5c5f0ac2009-10-27 21:49:40 +0000[diff] [blame]2423 basic block in the specified function, and always has an i8* type. Taking
Chris Lattneraa99c942009-11-01 01:27:45 +0000[diff] [blame]2424 the address of the entry block is illegal.</p>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]2425
Chris Lattnere4801f72009-10-27 21:01:34 +0000[diff] [blame]2426<p>This value only has defined behavior when used as an operand to the
Chris Lattnerd04cb6d2009-10-28 00:19:10 +0000[diff] [blame]2427 '<a href="#i_indirectbr"><tt>indirectbr</tt></a>' instruction or for comparisons
Chris Lattnere4801f72009-10-27 21:01:34 +0000[diff] [blame]2428 against null. Pointer equality tests between labels addresses is undefined
2429 behavior - though, again, comparison against null is ok, and no label is
Chris Lattner2bfd3202009-10-27 21:19:13 +0000[diff] [blame]2430 equal to the null pointer. This may also be passed around as an opaque
2431 pointer sized value as long as the bits are not inspected. This allows
Chris Lattnerda37b302009-10-27 21:44:20 +0000[diff] [blame]2432 <tt>ptrtoint</tt> and arithmetic to be performed on these values so long as
Chris Lattnerd04cb6d2009-10-28 00:19:10 +0000[diff] [blame]2433 the original value is reconstituted before the <tt>indirectbr</tt>.</p>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]2434
Chris Lattner2bfd3202009-10-27 21:19:13 +0000[diff] [blame]2435<p>Finally, some targets may provide defined semantics when
Chris Lattnere4801f72009-10-27 21:01:34 +0000[diff] [blame]2436 using the value as the operand to an inline assembly, but that is target
2437 specific.
2438 </p>
2439
2440</div>
2441
2442
2443<!-- ======================================================================= -->
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2444<div class="doc_subsection"><a name="constantexprs">Constant Expressions</a>
2445</div>
2446
2447<div class="doc_text">
2448
2449<p>Constant expressions are used to allow expressions involving other constants
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2450 to be used as constants. Constant expressions may be of
2451 any <a href="#t_firstclass">first class</a> type and may involve any LLVM
2452 operation that does not have side effects (e.g. load and call are not
2453 supported). The following is the syntax for constant expressions:</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2454
2455<dl>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2456 <dt><b><tt>trunc ( CST to TYPE )</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2457 <dd>Truncate a constant to another type. The bit size of CST must be larger
2458 than the bit size of TYPE. Both types must be integers.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2459
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2460 <dt><b><tt>zext ( CST to TYPE )</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2461 <dd>Zero extend a constant to another type. The bit size of CST must be
2462 smaller or equal to the bit size of TYPE. Both types must be
2463 integers.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2464
2465 <dt><b><tt>sext ( CST to TYPE )</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2466 <dd>Sign extend a constant to another type. The bit size of CST must be
2467 smaller or equal to the bit size of TYPE. Both types must be
2468 integers.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2469
2470 <dt><b><tt>fptrunc ( CST to TYPE )</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2471 <dd>Truncate a floating point constant to another floating point type. The
2472 size of CST must be larger than the size of TYPE. Both types must be
2473 floating point.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2474
2475 <dt><b><tt>fpext ( CST to TYPE )</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2476 <dd>Floating point extend a constant to another type. The size of CST must be
2477 smaller or equal to the size of TYPE. Both types must be floating
2478 point.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2479
Reid Spencer753163d2007-07-31 14:40:14 +0000[diff] [blame]2480 <dt><b><tt>fptoui ( CST to TYPE )</tt></b></dt>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2481 <dd>Convert a floating point constant to the corresponding unsigned integer
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2482 constant. TYPE must be a scalar or vector integer type. CST must be of
2483 scalar or vector floating point type. Both CST and TYPE must be scalars,
2484 or vectors of the same number of elements. If the value won't fit in the
2485 integer type, the results are undefined.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2486
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]2487 <dt><b><tt>fptosi ( CST to TYPE )</tt></b></dt>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2488 <dd>Convert a floating point constant to the corresponding signed integer
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2489 constant. TYPE must be a scalar or vector integer type. CST must be of
2490 scalar or vector floating point type. Both CST and TYPE must be scalars,
2491 or vectors of the same number of elements. If the value won't fit in the
2492 integer type, the results are undefined.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2493
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]2494 <dt><b><tt>uitofp ( CST to TYPE )</tt></b></dt>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2495 <dd>Convert an unsigned integer constant to the corresponding floating point
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2496 constant. TYPE must be a scalar or vector floating point type. CST must be
2497 of scalar or vector integer type. Both CST and TYPE must be scalars, or
2498 vectors of the same number of elements. If the value won't fit in the
2499 floating point type, the results are undefined.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2500
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]2501 <dt><b><tt>sitofp ( CST to TYPE )</tt></b></dt>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2502 <dd>Convert a signed integer constant to the corresponding floating point
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2503 constant. TYPE must be a scalar or vector floating point type. CST must be
2504 of scalar or vector integer type. Both CST and TYPE must be scalars, or
2505 vectors of the same number of elements. If the value won't fit in the
2506 floating point type, the results are undefined.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2507
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]2508 <dt><b><tt>ptrtoint ( CST to TYPE )</tt></b></dt>
2509 <dd>Convert a pointer typed constant to the corresponding integer constant
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2510 <tt>TYPE</tt> must be an integer type. <tt>CST</tt> must be of pointer
2511 type. The <tt>CST</tt> value is zero extended, truncated, or unchanged to
2512 make it fit in <tt>TYPE</tt>.</dd>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]2513
2514 <dt><b><tt>inttoptr ( CST to TYPE )</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2515 <dd>Convert a integer constant to a pointer constant. TYPE must be a pointer
2516 type. CST must be of integer type. The CST value is zero extended,
2517 truncated, or unchanged to make it fit in a pointer size. This one is
2518 <i>really</i> dangerous!</dd>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]2519
2520 <dt><b><tt>bitcast ( CST to TYPE )</tt></b></dt>
Chris Lattner789dee32009-02-28 18:27:03 +0000[diff] [blame]2521 <dd>Convert a constant, CST, to another TYPE. The constraints of the operands
2522 are the same as those for the <a href="#i_bitcast">bitcast
2523 instruction</a>.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2524
2525 <dt><b><tt>getelementptr ( CSTPTR, IDX0, IDX1, ... )</tt></b></dt>
Dan Gohman1639c392009-07-27 21:53:46 +0000[diff] [blame]2526 <dt><b><tt>getelementptr inbounds ( CSTPTR, IDX0, IDX1, ... )</tt></b></dt>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2527 <dd>Perform the <a href="#i_getelementptr">getelementptr operation</a> on
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2528 constants. As with the <a href="#i_getelementptr">getelementptr</a>
2529 instruction, the index list may have zero or more indexes, which are
2530 required to make sense for the type of "CSTPTR".</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2531
Robert Bocchino7e97a6d2006-01-10 19:31:34 +0000[diff] [blame]2532 <dt><b><tt>select ( COND, VAL1, VAL2 )</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2533 <dd>Perform the <a href="#i_select">select operation</a> on constants.</dd>
Reid Spencer9965ee72006-12-04 19:23:19 +0000[diff] [blame]2534
2535 <dt><b><tt>icmp COND ( VAL1, VAL2 )</tt></b></dt>
2536 <dd>Performs the <a href="#i_icmp">icmp operation</a> on constants.</dd>
2537
2538 <dt><b><tt>fcmp COND ( VAL1, VAL2 )</tt></b></dt>
2539 <dd>Performs the <a href="#i_fcmp">fcmp operation</a> on constants.</dd>
Robert Bocchino7e97a6d2006-01-10 19:31:34 +0000[diff] [blame]2540
2541 <dt><b><tt>extractelement ( VAL, IDX )</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2542 <dd>Perform the <a href="#i_extractelement">extractelement operation</a> on
2543 constants.</dd>
Robert Bocchino7e97a6d2006-01-10 19:31:34 +0000[diff] [blame]2544
Robert Bocchinof72fdfe2006-01-15 20:48:27 +0000[diff] [blame]2545 <dt><b><tt>insertelement ( VAL, ELT, IDX )</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2546 <dd>Perform the <a href="#i_insertelement">insertelement operation</a> on
2547 constants.</dd>
Chris Lattner016a0e52006-04-08 00:13:41 +0000[diff] [blame]2548
2549 <dt><b><tt>shufflevector ( VEC1, VEC2, IDXMASK )</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2550 <dd>Perform the <a href="#i_shufflevector">shufflevector operation</a> on
2551 constants.</dd>
Chris Lattner016a0e52006-04-08 00:13:41 +0000[diff] [blame]2552
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2553 <dt><b><tt>OPCODE ( LHS, RHS )</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2554 <dd>Perform the specified operation of the LHS and RHS constants. OPCODE may
2555 be any of the <a href="#binaryops">binary</a>
2556 or <a href="#bitwiseops">bitwise binary</a> operations. The constraints
2557 on operands are the same as those for the corresponding instruction
2558 (e.g. no bitwise operations on floating point values are allowed).</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2559</dl>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2560
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2561</div>
Chris Lattnerb1652612004-03-08 16:49:10 +0000[diff] [blame]2562
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2563<!-- *********************************************************************** -->
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2564<div class="doc_section"> <a name="othervalues">Other Values</a> </div>
2565<!-- *********************************************************************** -->
2566
2567<!-- ======================================================================= -->
2568<div class="doc_subsection">
2569<a name="inlineasm">Inline Assembler Expressions</a>
2570</div>
2571
2572<div class="doc_text">
2573
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2574<p>LLVM supports inline assembler expressions (as opposed
2575 to <a href="#moduleasm"> Module-Level Inline Assembly</a>) through the use of
2576 a special value. This value represents the inline assembler as a string
2577 (containing the instructions to emit), a list of operand constraints (stored
Dale Johannesen63c94fe2009-10-13 21:56:55 +0000[diff] [blame]2578 as a string), a flag that indicates whether or not the inline asm
Dale Johannesen1cfb9582009-10-21 23:28:00 +0000[diff] [blame]2579 expression has side effects, and a flag indicating whether the function
2580 containing the asm needs to align its stack conservatively. An example
2581 inline assembler expression is:</p>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2582
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2583<div class="doc_code">
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2584<pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2585i32 (i32) asm "bswap $0", "=r,r"
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2586</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2587</div>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2588
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2589<p>Inline assembler expressions may <b>only</b> be used as the callee operand of
2590 a <a href="#i_call"><tt>call</tt> instruction</a>. Thus, typically we
2591 have:</p>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2592
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2593<div class="doc_code">
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2594<pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2595%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]2596</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2597</div>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2598
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2599<p>Inline asms with side effects not visible in the constraint list must be
2600 marked as having side effects. This is done through the use of the
2601 '<tt>sideeffect</tt>' keyword, like so:</p>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2602
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2603<div class="doc_code">
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2604<pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2605call void asm sideeffect "eieio", ""()
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2606</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2607</div>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2608
Dale Johannesen1cfb9582009-10-21 23:28:00 +0000[diff] [blame]2609<p>In some cases inline asms will contain code that will not work unless the
2610 stack is aligned in some way, such as calls or SSE instructions on x86,
2611 yet will not contain code that does that alignment within the asm.
2612 The compiler should make conservative assumptions about what the asm might
2613 contain and should generate its usual stack alignment code in the prologue
2614 if the '<tt>alignstack</tt>' keyword is present:</p>
Dale Johannesen63c94fe2009-10-13 21:56:55 +0000[diff] [blame]2615
2616<div class="doc_code">
2617<pre>
Dale Johannesen1cfb9582009-10-21 23:28:00 +0000[diff] [blame]2618call void asm alignstack "eieio", ""()
Dale Johannesen63c94fe2009-10-13 21:56:55 +0000[diff] [blame]2619</pre>
2620</div>
2621
2622<p>If both keywords appear the '<tt>sideeffect</tt>' keyword must come
2623 first.</p>
2624
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2625<p>TODO: The format of the asm and constraints string still need to be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2626 documented here. Constraints on what can be done (e.g. duplication, moving,
2627 etc need to be documented). This is probably best done by reference to
2628 another document that covers inline asm from a holistic perspective.</p>
Chris Lattner51065562010-04-07 05:38:05 +0000[diff] [blame]2629</div>
2630
2631<div class="doc_subsubsection">
2632<a name="inlineasm_md">Inline Asm Metadata</a>
2633</div>
2634
2635<div class="doc_text">
2636
2637<p>The call instructions that wrap inline asm nodes may have a "!srcloc" MDNode
2638 attached to it that contains a constant integer. If present, the code
2639 generator will use the integer as the location cookie value when report
2640 errors through the LLVMContext error reporting mechanisms. This allows a
Dan Gohman61110ae2010-04-28 00:36:01 +0000[diff] [blame^]2641 front-end to correlate backend errors that occur with inline asm back to the
Chris Lattner51065562010-04-07 05:38:05 +0000[diff] [blame]2642 source code that produced it. For example:</p>
2643
2644<div class="doc_code">
2645<pre>
2646call void asm sideeffect "something bad", ""()<b>, !srcloc !42</b>
2647...
2648!42 = !{ i32 1234567 }
2649</pre>
2650</div>
2651
2652<p>It is up to the front-end to make sense of the magic numbers it places in the
2653 IR.</p>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2654
2655</div>
2656
Chris Lattnerc2f8f162010-01-15 21:50:19 +0000[diff] [blame]2657<!-- ======================================================================= -->
2658<div class="doc_subsection"><a name="metadata">Metadata Nodes and Metadata
2659 Strings</a>
2660</div>
2661
2662<div class="doc_text">
2663
2664<p>LLVM IR allows metadata to be attached to instructions in the program that
2665 can convey extra information about the code to the optimizers and code
2666 generator. One example application of metadata is source-level debug
2667 information. There are two metadata primitives: strings and nodes. All
2668 metadata has the <tt>metadata</tt> type and is identified in syntax by a
2669 preceding exclamation point ('<tt>!</tt>').</p>
2670
2671<p>A metadata string is a string surrounded by double quotes. It can contain
2672 any character by escaping non-printable characters with "\xx" where "xx" is
2673 the two digit hex code. For example: "<tt>!"test\00"</tt>".</p>
2674
2675<p>Metadata nodes are represented with notation similar to structure constants
2676 (a comma separated list of elements, surrounded by braces and preceded by an
2677 exclamation point). For example: "<tt>!{ metadata !"test\00", i32
2678 10}</tt>". Metadata nodes can have any values as their operand.</p>
2679
2680<p>A <a href="#namedmetadatastructure">named metadata</a> is a collection of
2681 metadata nodes, which can be looked up in the module symbol table. For
2682 example: "<tt>!foo = metadata !{!4, !3}</tt>".
2683
Devang Patel9984bd62010-03-04 23:44:48 +0000[diff] [blame]2684<p>Metadata can be used as function arguments. Here <tt>llvm.dbg.value</tt>
2685 function is using two metadata arguments.
2686
2687 <div class="doc_code">
2688 <pre>
2689 call void @llvm.dbg.value(metadata !24, i64 0, metadata !25)
2690 </pre>
2691 </div></p>
2692
2693<p>Metadata can be attached with an instruction. Here metadata <tt>!21</tt> is
2694 attached with <tt>add</tt> instruction using <tt>!dbg</tt> identifier.
2695
2696 <div class="doc_code">
2697 <pre>
2698 %indvar.next = add i64 %indvar, 1, !dbg !21
2699 </pre>
2700 </div></p>
Chris Lattnerc2f8f162010-01-15 21:50:19 +0000[diff] [blame]2701</div>
2702
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]2703
2704<!-- *********************************************************************** -->
2705<div class="doc_section">
2706 <a name="intrinsic_globals">Intrinsic Global Variables</a>
2707</div>
2708<!-- *********************************************************************** -->
2709
2710<p>LLVM has a number of "magic" global variables that contain data that affect
2711code generation or other IR semantics. These are documented here. All globals
Chris Lattner58f9bb22009-07-20 06:14:25 +0000[diff] [blame]2712of this sort should have a section specified as "<tt>llvm.metadata</tt>". This
2713section and all globals that start with "<tt>llvm.</tt>" are reserved for use
2714by LLVM.</p>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]2715
2716<!-- ======================================================================= -->
2717<div class="doc_subsection">
2718<a name="intg_used">The '<tt>llvm.used</tt>' Global Variable</a>
2719</div>
2720
2721<div class="doc_text">
2722
2723<p>The <tt>@llvm.used</tt> global is an array with i8* element type which has <a
2724href="#linkage_appending">appending linkage</a>. This array contains a list of
2725pointers to global variables and functions which may optionally have a pointer
2726cast formed of bitcast or getelementptr. For example, a legal use of it is:</p>
2727
2728<pre>
2729 @X = global i8 4
2730 @Y = global i32 123
2731
2732 @llvm.used = appending global [2 x i8*] [
2733 i8* @X,
2734 i8* bitcast (i32* @Y to i8*)
2735 ], section "llvm.metadata"
2736</pre>
2737
2738<p>If a global variable appears in the <tt>@llvm.used</tt> list, then the
2739compiler, assembler, and linker are required to treat the symbol as if there is
2740a reference to the global that it cannot see. For example, if a variable has
2741internal linkage and no references other than that from the <tt>@llvm.used</tt>
2742list, it cannot be deleted. This is commonly used to represent references from
2743inline asms and other things the compiler cannot "see", and corresponds to
2744"attribute((used))" in GNU C.</p>
2745
2746<p>On some targets, the code generator must emit a directive to the assembler or
2747object file to prevent the assembler and linker from molesting the symbol.</p>
2748
2749</div>
2750
2751<!-- ======================================================================= -->
2752<div class="doc_subsection">
Chris Lattner58f9bb22009-07-20 06:14:25 +0000[diff] [blame]2753<a name="intg_compiler_used">The '<tt>llvm.compiler.used</tt>' Global Variable</a>
2754</div>
2755
2756<div class="doc_text">
2757
2758<p>The <tt>@llvm.compiler.used</tt> directive is the same as the
2759<tt>@llvm.used</tt> directive, except that it only prevents the compiler from
2760touching the symbol. On targets that support it, this allows an intelligent
2761linker to optimize references to the symbol without being impeded as it would be
2762by <tt>@llvm.used</tt>.</p>
2763
2764<p>This is a rare construct that should only be used in rare circumstances, and
2765should not be exposed to source languages.</p>
2766
2767</div>
2768
2769<!-- ======================================================================= -->
2770<div class="doc_subsection">
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]2771<a name="intg_global_ctors">The '<tt>llvm.global_ctors</tt>' Global Variable</a>
2772</div>
2773
2774<div class="doc_text">
2775
2776<p>TODO: Describe this.</p>
2777
2778</div>
2779
2780<!-- ======================================================================= -->
2781<div class="doc_subsection">
2782<a name="intg_global_dtors">The '<tt>llvm.global_dtors</tt>' Global Variable</a>
2783</div>
2784
2785<div class="doc_text">
2786
2787<p>TODO: Describe this.</p>
2788
2789</div>
2790
2791
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2792<!-- *********************************************************************** -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2793<div class="doc_section"> <a name="instref">Instruction Reference</a> </div>
2794<!-- *********************************************************************** -->
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2795
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2796<div class="doc_text">
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2797
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2798<p>The LLVM instruction set consists of several different classifications of
2799 instructions: <a href="#terminators">terminator
2800 instructions</a>, <a href="#binaryops">binary instructions</a>,
2801 <a href="#bitwiseops">bitwise binary instructions</a>,
2802 <a href="#memoryops">memory instructions</a>, and
2803 <a href="#otherops">other instructions</a>.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2804
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2805</div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2806
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2807<!-- ======================================================================= -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2808<div class="doc_subsection"> <a name="terminators">Terminator
2809Instructions</a> </div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2810
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2811<div class="doc_text">
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2812
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2813<p>As mentioned <a href="#functionstructure">previously</a>, every basic block
2814 in a program ends with a "Terminator" instruction, which indicates which
2815 block should be executed after the current block is finished. These
2816 terminator instructions typically yield a '<tt>void</tt>' value: they produce
2817 control flow, not values (the one exception being the
2818 '<a href="#i_invoke"><tt>invoke</tt></a>' instruction).</p>
2819
Duncan Sands626b0242010-04-15 20:35:54 +0000[diff] [blame]2820<p>There are seven different terminator instructions: the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2821 '<a href="#i_ret"><tt>ret</tt></a>' instruction, the
2822 '<a href="#i_br"><tt>br</tt></a>' instruction, the
2823 '<a href="#i_switch"><tt>switch</tt></a>' instruction, the
Bill Wendling33fef7e2009-11-02 00:25:26 +0000[diff] [blame]2824 '<a href="#i_indirectbr">'<tt>indirectbr</tt></a>' Instruction, the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2825 '<a href="#i_invoke"><tt>invoke</tt></a>' instruction, the
2826 '<a href="#i_unwind"><tt>unwind</tt></a>' instruction, and the
2827 '<a href="#i_unreachable"><tt>unreachable</tt></a>' instruction.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2828
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2829</div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2830
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2831<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2832<div class="doc_subsubsection"> <a name="i_ret">'<tt>ret</tt>'
2833Instruction</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2834
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2835<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2836
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2837<h5>Syntax:</h5>
Dan Gohmancc3132e2008-10-04 19:00:07 +0000[diff] [blame]2838<pre>
2839 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]2840 ret void <i>; Return from void function</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2841</pre>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]2842
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2843<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2844<p>The '<tt>ret</tt>' instruction is used to return control flow (and optionally
2845 a value) from a function back to the caller.</p>
2846
2847<p>There are two forms of the '<tt>ret</tt>' instruction: one that returns a
2848 value and then causes control flow, and one that just causes control flow to
2849 occur.</p>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]2850
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2851<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2852<p>The '<tt>ret</tt>' instruction optionally accepts a single argument, the
2853 return value. The type of the return value must be a
2854 '<a href="#t_firstclass">first class</a>' type.</p>
Dan Gohmancc3132e2008-10-04 19:00:07 +0000[diff] [blame]2855
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2856<p>A function is not <a href="#wellformed">well formed</a> if it it has a
2857 non-void return type and contains a '<tt>ret</tt>' instruction with no return
2858 value or a return value with a type that does not match its type, or if it
2859 has a void return type and contains a '<tt>ret</tt>' instruction with a
2860 return value.</p>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]2861
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2862<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2863<p>When the '<tt>ret</tt>' instruction is executed, control flow returns back to
2864 the calling function's context. If the caller is a
2865 "<a href="#i_call"><tt>call</tt></a>" instruction, execution continues at the
2866 instruction after the call. If the caller was an
2867 "<a href="#i_invoke"><tt>invoke</tt></a>" instruction, execution continues at
2868 the beginning of the "normal" destination block. If the instruction returns
2869 a value, that value shall set the call or invoke instruction's return
2870 value.</p>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]2871
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2872<h5>Example:</h5>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]2873<pre>
2874 ret i32 5 <i>; Return an integer value of 5</i>
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]2875 ret void <i>; Return from a void function</i>
Bill Wendling050ee8f2009-02-28 22:12:54 +0000[diff] [blame]2876 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]2877</pre>
Dan Gohman3065b612009-01-12 23:12:39 +0000[diff] [blame]2878
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2879</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2880<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2881<div class="doc_subsubsection"> <a name="i_br">'<tt>br</tt>' Instruction</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2882
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2883<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2884
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2885<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2886<pre>
2887 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]2888</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2889
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2890<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2891<p>The '<tt>br</tt>' instruction is used to cause control flow to transfer to a
2892 different basic block in the current function. There are two forms of this
2893 instruction, corresponding to a conditional branch and an unconditional
2894 branch.</p>
2895
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2896<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2897<p>The conditional branch form of the '<tt>br</tt>' instruction takes a single
2898 '<tt>i1</tt>' value and two '<tt>label</tt>' values. The unconditional form
2899 of the '<tt>br</tt>' instruction takes a single '<tt>label</tt>' value as a
2900 target.</p>
2901
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2902<h5>Semantics:</h5>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]2903<p>Upon execution of a conditional '<tt>br</tt>' instruction, the '<tt>i1</tt>'
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2904 argument is evaluated. If the value is <tt>true</tt>, control flows to the
2905 '<tt>iftrue</tt>' <tt>label</tt> argument. If "cond" is <tt>false</tt>,
2906 control flows to the '<tt>iffalse</tt>' <tt>label</tt> argument.</p>
2907
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2908<h5>Example:</h5>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]2909<pre>
2910Test:
2911 %cond = <a href="#i_icmp">icmp</a> eq i32 %a, %b
2912 br i1 %cond, label %IfEqual, label %IfUnequal
2913IfEqual:
2914 <a href="#i_ret">ret</a> i32 1
2915IfUnequal:
2916 <a href="#i_ret">ret</a> i32 0
2917</pre>
2918
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2919</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2920
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2921<!-- _______________________________________________________________________ -->
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2922<div class="doc_subsubsection">
2923 <a name="i_switch">'<tt>switch</tt>' Instruction</a>
2924</div>
2925
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2926<div class="doc_text">
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2927
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2928<h5>Syntax:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2929<pre>
2930 switch &lt;intty&gt; &lt;value&gt;, label &lt;defaultdest&gt; [ &lt;intty&gt; &lt;val&gt;, label &lt;dest&gt; ... ]
2931</pre>
2932
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2933<h5>Overview:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2934<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]2935 several different places. It is a generalization of the '<tt>br</tt>'
2936 instruction, allowing a branch to occur to one of many possible
2937 destinations.</p>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2938
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2939<h5>Arguments:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2940<p>The '<tt>switch</tt>' instruction uses three parameters: an integer
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2941 comparison value '<tt>value</tt>', a default '<tt>label</tt>' destination,
2942 and an array of pairs of comparison value constants and '<tt>label</tt>'s.
2943 The table is not allowed to contain duplicate constant entries.</p>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2944
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2945<h5>Semantics:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2946<p>The <tt>switch</tt> instruction specifies a table of values and
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2947 destinations. When the '<tt>switch</tt>' instruction is executed, this table
2948 is searched for the given value. If the value is found, control flow is
Benjamin Kramer0f420382009-10-12 14:46:08 +0000[diff] [blame]2949 transferred to the corresponding destination; otherwise, control flow is
2950 transferred to the default destination.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2951
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2952<h5>Implementation:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2953<p>Depending on properties of the target machine and the particular
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2954 <tt>switch</tt> instruction, this instruction may be code generated in
2955 different ways. For example, it could be generated as a series of chained
2956 conditional branches or with a lookup table.</p>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2957
2958<h5>Example:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2959<pre>
2960 <i>; Emulate a conditional br instruction</i>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]2961 %Val = <a href="#i_zext">zext</a> i1 %value to i32
Dan Gohman623806e2009-01-04 23:44:43 +0000[diff] [blame]2962 switch i32 %Val, label %truedest [ i32 0, label %falsedest ]
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2963
2964 <i>; Emulate an unconditional br instruction</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2965 switch i32 0, label %dest [ ]
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2966
2967 <i>; Implement a jump table:</i>
Dan Gohman623806e2009-01-04 23:44:43 +0000[diff] [blame]2968 switch i32 %val, label %otherwise [ i32 0, label %onzero
2969 i32 1, label %onone
2970 i32 2, label %ontwo ]
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2971</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2972
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2973</div>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]2974
Chris Lattner3ed871f2009-10-27 19:13:16 +0000[diff] [blame]2975
2976<!-- _______________________________________________________________________ -->
2977<div class="doc_subsubsection">
Chris Lattnerd04cb6d2009-10-28 00:19:10 +0000[diff] [blame]2978 <a name="i_indirectbr">'<tt>indirectbr</tt>' Instruction</a>
Chris Lattner3ed871f2009-10-27 19:13:16 +0000[diff] [blame]2979</div>
2980
2981<div class="doc_text">
2982
2983<h5>Syntax:</h5>
2984<pre>
Chris Lattnerd04cb6d2009-10-28 00:19:10 +0000[diff] [blame]2985 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]2986</pre>
2987
2988<h5>Overview:</h5>
2989
Chris Lattnerd04cb6d2009-10-28 00:19:10 +0000[diff] [blame]2990<p>The '<tt>indirectbr</tt>' instruction implements an indirect branch to a label
Chris Lattner3ed871f2009-10-27 19:13:16 +0000[diff] [blame]2991 within the current function, whose address is specified by
Chris Lattnere4801f72009-10-27 21:01:34 +0000[diff] [blame]2992 "<tt>address</tt>". Address must be derived from a <a
2993 href="#blockaddress">blockaddress</a> constant.</p>
Chris Lattner3ed871f2009-10-27 19:13:16 +0000[diff] [blame]2994
2995<h5>Arguments:</h5>
2996
2997<p>The '<tt>address</tt>' argument is the address of the label to jump to. The
2998 rest of the arguments indicate the full set of possible destinations that the
2999 address may point to. Blocks are allowed to occur multiple times in the
3000 destination list, though this isn't particularly useful.</p>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3001
Chris Lattner3ed871f2009-10-27 19:13:16 +0000[diff] [blame]3002<p>This destination list is required so that dataflow analysis has an accurate
3003 understanding of the CFG.</p>
3004
3005<h5>Semantics:</h5>
3006
3007<p>Control transfers to the block specified in the address argument. All
3008 possible destination blocks must be listed in the label list, otherwise this
3009 instruction has undefined behavior. This implies that jumps to labels
3010 defined in other functions have undefined behavior as well.</p>
3011
3012<h5>Implementation:</h5>
3013
3014<p>This is typically implemented with a jump through a register.</p>
3015
3016<h5>Example:</h5>
3017<pre>
Chris Lattnerd04cb6d2009-10-28 00:19:10 +0000[diff] [blame]3018 indirectbr i8* %Addr, [ label %bb1, label %bb2, label %bb3 ]
Chris Lattner3ed871f2009-10-27 19:13:16 +0000[diff] [blame]3019</pre>
3020
3021</div>
3022
3023
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3024<!-- _______________________________________________________________________ -->
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3025<div class="doc_subsubsection">
3026 <a name="i_invoke">'<tt>invoke</tt>' Instruction</a>
3027</div>
3028
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3029<div class="doc_text">
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3030
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3031<h5>Syntax:</h5>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3032<pre>
Devang Patel02256232008-10-07 17:48:33 +0000[diff] [blame]3033 &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]3034 to label &lt;normal label&gt; unwind label &lt;exception label&gt;
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3035</pre>
3036
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]3037<h5>Overview:</h5>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3038<p>The '<tt>invoke</tt>' instruction causes control to transfer to a specified
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3039 function, with the possibility of control flow transfer to either the
3040 '<tt>normal</tt>' label or the '<tt>exception</tt>' label. If the callee
3041 function returns with the "<tt><a href="#i_ret">ret</a></tt>" instruction,
3042 control flow will return to the "normal" label. If the callee (or any
3043 indirect callees) returns with the "<a href="#i_unwind"><tt>unwind</tt></a>"
3044 instruction, control is interrupted and continued at the dynamically nearest
3045 "exception" label.</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3046
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3047<h5>Arguments:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3048<p>This instruction requires several arguments:</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3049
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3050<ol>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3051 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
3052 convention</a> the call should use. If none is specified, the call
3053 defaults to using C calling conventions.</li>
Devang Patel7e9b05e2008-10-06 18:50:38 +0000[diff] [blame]3054
3055 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3056 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
3057 '<tt>inreg</tt>' attributes are valid here.</li>
Devang Patel7e9b05e2008-10-06 18:50:38 +0000[diff] [blame]3058
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3059 <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]3060 function value being invoked. In most cases, this is a direct function
3061 invocation, but indirect <tt>invoke</tt>s are just as possible, branching
3062 off an arbitrary pointer to function value.</li>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3063
3064 <li>'<tt>function ptr val</tt>': An LLVM value containing a pointer to a
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3065 function to be invoked. </li>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3066
3067 <li>'<tt>function args</tt>': argument list whose types match the function
Chris Lattner47f2a832010-03-02 06:36:51 +0000[diff] [blame]3068 signature argument types and parameter attributes. All arguments must be
3069 of <a href="#t_firstclass">first class</a> type. If the function
3070 signature indicates the function accepts a variable number of arguments,
3071 the extra arguments can be specified.</li>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3072
3073 <li>'<tt>normal label</tt>': the label reached when the called function
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3074 executes a '<tt><a href="#i_ret">ret</a></tt>' instruction. </li>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3075
3076 <li>'<tt>exception label</tt>': the label reached when a callee returns with
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3077 the <a href="#i_unwind"><tt>unwind</tt></a> instruction. </li>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3078
Devang Patel02256232008-10-07 17:48:33 +0000[diff] [blame]3079 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3080 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
3081 '<tt>readnone</tt>' attributes are valid here.</li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3082</ol>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3083
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3084<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3085<p>This instruction is designed to operate as a standard
3086 '<tt><a href="#i_call">call</a></tt>' instruction in most regards. The
3087 primary difference is that it establishes an association with a label, which
3088 is used by the runtime library to unwind the stack.</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3089
3090<p>This instruction is used in languages with destructors to ensure that proper
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3091 cleanup is performed in the case of either a <tt>longjmp</tt> or a thrown
3092 exception. Additionally, this is important for implementation of
3093 '<tt>catch</tt>' clauses in high-level languages that support them.</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3094
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3095<p>For the purposes of the SSA form, the definition of the value returned by the
3096 '<tt>invoke</tt>' instruction is deemed to occur on the edge from the current
3097 block to the "normal" label. If the callee unwinds then no return value is
3098 available.</p>
Dan Gohman9069d892009-05-22 21:47:08 +0000[diff] [blame]3099
Chris Lattner97257f82010-01-15 18:08:37 +0000[diff] [blame]3100<p>Note that the code generator does not yet completely support unwind, and
3101that the invoke/unwind semantics are likely to change in future versions.</p>
3102
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3103<h5>Example:</h5>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3104<pre>
Nick Lewycky084ab472008-03-16 07:18:12 +0000[diff] [blame]3105 %retval = invoke i32 @Test(i32 15) to label %Continue
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]3106 unwind label %TestCleanup <i>; {i32}:retval set</i>
Nick Lewycky084ab472008-03-16 07:18:12 +0000[diff] [blame]3107 %retval = invoke <a href="#callingconv">coldcc</a> i32 %Testfnptr(i32 15) to label %Continue
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]3108 unwind label %TestCleanup <i>; {i32}:retval set</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3109</pre>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3110
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3111</div>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3112
Chris Lattner5ed60612003-09-03 00:41:47 +0000[diff] [blame]3113<!-- _______________________________________________________________________ -->
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3114
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3115<div class="doc_subsubsection"> <a name="i_unwind">'<tt>unwind</tt>'
3116Instruction</a> </div>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3117
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3118<div class="doc_text">
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3119
Chris Lattner5ed60612003-09-03 00:41:47 +0000[diff] [blame]3120<h5>Syntax:</h5>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3121<pre>
3122 unwind
3123</pre>
3124
Chris Lattner5ed60612003-09-03 00:41:47 +0000[diff] [blame]3125<h5>Overview:</h5>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3126<p>The '<tt>unwind</tt>' instruction unwinds the stack, continuing control flow
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3127 at the first callee in the dynamic call stack which used
3128 an <a href="#i_invoke"><tt>invoke</tt></a> instruction to perform the call.
3129 This is primarily used to implement exception handling.</p>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3130
Chris Lattner5ed60612003-09-03 00:41:47 +0000[diff] [blame]3131<h5>Semantics:</h5>
Chris Lattnerfe8519c2008-04-19 21:01:16 +0000[diff] [blame]3132<p>The '<tt>unwind</tt>' instruction causes execution of the current function to
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3133 immediately halt. The dynamic call stack is then searched for the
3134 first <a href="#i_invoke"><tt>invoke</tt></a> instruction on the call stack.
3135 Once found, execution continues at the "exceptional" destination block
3136 specified by the <tt>invoke</tt> instruction. If there is no <tt>invoke</tt>
3137 instruction in the dynamic call chain, undefined behavior results.</p>
3138
Chris Lattner97257f82010-01-15 18:08:37 +0000[diff] [blame]3139<p>Note that the code generator does not yet completely support unwind, and
3140that the invoke/unwind semantics are likely to change in future versions.</p>
3141
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3142</div>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3143
3144<!-- _______________________________________________________________________ -->
3145
3146<div class="doc_subsubsection"> <a name="i_unreachable">'<tt>unreachable</tt>'
3147Instruction</a> </div>
3148
3149<div class="doc_text">
3150
3151<h5>Syntax:</h5>
3152<pre>
3153 unreachable
3154</pre>
3155
3156<h5>Overview:</h5>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3157<p>The '<tt>unreachable</tt>' instruction has no defined semantics. This
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3158 instruction is used to inform the optimizer that a particular portion of the
3159 code is not reachable. This can be used to indicate that the code after a
3160 no-return function cannot be reached, and other facts.</p>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3161
3162<h5>Semantics:</h5>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3163<p>The '<tt>unreachable</tt>' instruction has no defined semantics.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3164
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3165</div>
3166
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3167<!-- ======================================================================= -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3168<div class="doc_subsection"> <a name="binaryops">Binary Operations</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3169
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3170<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3171
3172<p>Binary operators are used to do most of the computation in a program. They
3173 require two operands of the same type, execute an operation on them, and
3174 produce a single value. The operands might represent multiple data, as is
3175 the case with the <a href="#t_vector">vector</a> data type. The result value
3176 has the same type as its operands.</p>
3177
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3178<p>There are several different binary operators:</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3179
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3180</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3181
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3182<!-- _______________________________________________________________________ -->
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3183<div class="doc_subsubsection">
3184 <a name="i_add">'<tt>add</tt>' Instruction</a>
3185</div>
3186
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3187<div class="doc_text">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3188
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3189<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3190<pre>
Dan Gohmanb07de442009-07-20 22:41:19 +0000[diff] [blame]3191 &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]3192 &lt;result&gt; = add nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3193 &lt;result&gt; = add nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3194 &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]3195</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3196
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3197<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3198<p>The '<tt>add</tt>' instruction returns the sum of its two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3199
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3200<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3201<p>The two arguments to the '<tt>add</tt>' instruction must
3202 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3203 integer values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3204
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3205<h5>Semantics:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3206<p>The value produced is the integer sum of the two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3207
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3208<p>If the sum has unsigned overflow, the result returned is the mathematical
3209 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]3210
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3211<p>Because LLVM integers use a two's complement representation, this instruction
3212 is appropriate for both signed and unsigned integers.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3213
Dan Gohman902dfff2009-07-22 22:44:56 +0000[diff] [blame]3214<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3215 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3216 <tt>nsw</tt> keywords are present, the result value of the <tt>add</tt>
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]3217 is a <a href="#trapvalues">trap value</a> if unsigned and/or signed overflow,
3218 respectively, occurs.</p>
Dan Gohmanb07de442009-07-20 22:41:19 +0000[diff] [blame]3219
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3220<h5>Example:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3221<pre>
3222 &lt;result&gt; = add i32 4, %var <i>; yields {i32}:result = 4 + %var</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3223</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3224
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3225</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3226
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3227<!-- _______________________________________________________________________ -->
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3228<div class="doc_subsubsection">
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3229 <a name="i_fadd">'<tt>fadd</tt>' Instruction</a>
3230</div>
3231
3232<div class="doc_text">
3233
3234<h5>Syntax:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3235<pre>
3236 &lt;result&gt; = fadd &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3237</pre>
3238
3239<h5>Overview:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3240<p>The '<tt>fadd</tt>' instruction returns the sum of its two operands.</p>
3241
3242<h5>Arguments:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3243<p>The two arguments to the '<tt>fadd</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3244 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3245 floating point values. Both arguments must have identical types.</p>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3246
3247<h5>Semantics:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3248<p>The value produced is the floating point sum of the two operands.</p>
3249
3250<h5>Example:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3251<pre>
3252 &lt;result&gt; = fadd float 4.0, %var <i>; yields {float}:result = 4.0 + %var</i>
3253</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3254
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3255</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3256
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3257<!-- _______________________________________________________________________ -->
3258<div class="doc_subsubsection">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3259 <a name="i_sub">'<tt>sub</tt>' Instruction</a>
3260</div>
3261
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3262<div class="doc_text">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3263
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3264<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3265<pre>
Dan Gohman902dfff2009-07-22 22:44:56 +0000[diff] [blame]3266 &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]3267 &lt;result&gt; = sub nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3268 &lt;result&gt; = sub nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3269 &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]3270</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3271
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3272<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3273<p>The '<tt>sub</tt>' instruction returns the difference of its two
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3274 operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3275
3276<p>Note that the '<tt>sub</tt>' instruction is used to represent the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3277 '<tt>neg</tt>' instruction present in most other intermediate
3278 representations.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3279
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3280<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3281<p>The two arguments to the '<tt>sub</tt>' instruction must
3282 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3283 integer values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3284
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3285<h5>Semantics:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3286<p>The value produced is the integer difference of the two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3287
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3288<p>If the difference has unsigned overflow, the result returned is the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3289 mathematical result modulo 2<sup>n</sup>, where n is the bit width of the
3290 result.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3291
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3292<p>Because LLVM integers use a two's complement representation, this instruction
3293 is appropriate for both signed and unsigned integers.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3294
Dan Gohman902dfff2009-07-22 22:44:56 +0000[diff] [blame]3295<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3296 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3297 <tt>nsw</tt> keywords are present, the result value of the <tt>sub</tt>
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]3298 is a <a href="#trapvalues">trap value</a> if unsigned and/or signed overflow,
3299 respectively, occurs.</p>
Dan Gohmanb07de442009-07-20 22:41:19 +0000[diff] [blame]3300
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3301<h5>Example:</h5>
Bill Wendling2d8b9a82007-05-29 09:42:13 +0000[diff] [blame]3302<pre>
3303 &lt;result&gt; = sub i32 4, %var <i>; yields {i32}:result = 4 - %var</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3304 &lt;result&gt; = sub i32 0, %val <i>; yields {i32}:result = -%var</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3305</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3306
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3307</div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3308
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3309<!-- _______________________________________________________________________ -->
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3310<div class="doc_subsubsection">
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3311 <a name="i_fsub">'<tt>fsub</tt>' Instruction</a>
3312</div>
3313
3314<div class="doc_text">
3315
3316<h5>Syntax:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3317<pre>
3318 &lt;result&gt; = fsub &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3319</pre>
3320
3321<h5>Overview:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3322<p>The '<tt>fsub</tt>' instruction returns the difference of its two
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3323 operands.</p>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3324
3325<p>Note that the '<tt>fsub</tt>' instruction is used to represent the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3326 '<tt>fneg</tt>' instruction present in most other intermediate
3327 representations.</p>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3328
3329<h5>Arguments:</h5>
Bill Wendling972b7202009-07-20 02:32:41 +0000[diff] [blame]3330<p>The two arguments to the '<tt>fsub</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3331 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3332 floating point values. Both arguments must have identical types.</p>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3333
3334<h5>Semantics:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3335<p>The value produced is the floating point difference of the two operands.</p>
3336
3337<h5>Example:</h5>
3338<pre>
3339 &lt;result&gt; = fsub float 4.0, %var <i>; yields {float}:result = 4.0 - %var</i>
3340 &lt;result&gt; = fsub float -0.0, %val <i>; yields {float}:result = -%var</i>
3341</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3342
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3343</div>
3344
3345<!-- _______________________________________________________________________ -->
3346<div class="doc_subsubsection">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3347 <a name="i_mul">'<tt>mul</tt>' Instruction</a>
3348</div>
3349
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3350<div class="doc_text">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3351
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3352<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3353<pre>
Dan Gohman902dfff2009-07-22 22:44:56 +0000[diff] [blame]3354 &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]3355 &lt;result&gt; = mul nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3356 &lt;result&gt; = mul nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3357 &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]3358</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3359
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3360<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3361<p>The '<tt>mul</tt>' instruction returns the product of its two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3362
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3363<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3364<p>The two arguments to the '<tt>mul</tt>' instruction must
3365 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3366 integer values. Both arguments must have identical types.</p>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3367
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3368<h5>Semantics:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3369<p>The value produced is the integer product of the two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3370
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3371<p>If the result of the multiplication has unsigned overflow, the result
3372 returned is the mathematical result modulo 2<sup>n</sup>, where n is the bit
3373 width of the result.</p>
3374
3375<p>Because LLVM integers use a two's complement representation, and the result
3376 is the same width as the operands, this instruction returns the correct
3377 result for both signed and unsigned integers. If a full product
3378 (e.g. <tt>i32</tt>x<tt>i32</tt>-><tt>i64</tt>) is needed, the operands should
3379 be sign-extended or zero-extended as appropriate to the width of the full
3380 product.</p>
3381
Dan Gohman902dfff2009-07-22 22:44:56 +0000[diff] [blame]3382<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3383 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3384 <tt>nsw</tt> keywords are present, the result value of the <tt>mul</tt>
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]3385 is a <a href="#trapvalues">trap value</a> if unsigned and/or signed overflow,
3386 respectively, occurs.</p>
Dan Gohmanb07de442009-07-20 22:41:19 +0000[diff] [blame]3387
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3388<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3389<pre>
3390 &lt;result&gt; = mul i32 4, %var <i>; yields {i32}:result = 4 * %var</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3391</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3392
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3393</div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3394
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3395<!-- _______________________________________________________________________ -->
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3396<div class="doc_subsubsection">
3397 <a name="i_fmul">'<tt>fmul</tt>' Instruction</a>
3398</div>
3399
3400<div class="doc_text">
3401
3402<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3403<pre>
3404 &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]3405</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3406
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3407<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3408<p>The '<tt>fmul</tt>' instruction returns the product of its two operands.</p>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3409
3410<h5>Arguments:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3411<p>The two arguments to the '<tt>fmul</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3412 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3413 floating point values. Both arguments must have identical types.</p>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3414
3415<h5>Semantics:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3416<p>The value produced is the floating point product of the two operands.</p>
3417
3418<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3419<pre>
3420 &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]3421</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3422
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3423</div>
3424
3425<!-- _______________________________________________________________________ -->
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3426<div class="doc_subsubsection"> <a name="i_udiv">'<tt>udiv</tt>' Instruction
3427</a></div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3428
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3429<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3430
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3431<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3432<pre>
3433 &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]3434</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3435
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3436<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3437<p>The '<tt>udiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3438
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3439<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3440<p>The two arguments to the '<tt>udiv</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3441 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3442 values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3443
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3444<h5>Semantics:</h5>
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3445<p>The value produced is the unsigned integer quotient of the two operands.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3446
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3447<p>Note that unsigned integer division and signed integer division are distinct
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3448 operations; for signed integer division, use '<tt>sdiv</tt>'.</p>
3449
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3450<p>Division by zero leads to undefined behavior.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3451
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3452<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3453<pre>
3454 &lt;result&gt; = udiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3455</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3456
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3457</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3458
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3459<!-- _______________________________________________________________________ -->
3460<div class="doc_subsubsection"> <a name="i_sdiv">'<tt>sdiv</tt>' Instruction
3461</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3462
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3463<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3464
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3465<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3466<pre>
Dan Gohmanb07de442009-07-20 22:41:19 +0000[diff] [blame]3467 &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]3468 &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]3469</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3470
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3471<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3472<p>The '<tt>sdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3473
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3474<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3475<p>The two arguments to the '<tt>sdiv</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3476 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3477 values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3478
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3479<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3480<p>The value produced is the signed integer quotient of the two operands rounded
3481 towards zero.</p>
3482
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3483<p>Note that signed integer division and unsigned integer division are distinct
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3484 operations; for unsigned integer division, use '<tt>udiv</tt>'.</p>
3485
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3486<p>Division by zero leads to undefined behavior. Overflow also leads to
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3487 undefined behavior; this is a rare case, but can occur, for example, by doing
3488 a 32-bit division of -2147483648 by -1.</p>
3489
Dan Gohman71dfd782009-07-22 00:04:19 +0000[diff] [blame]3490<p>If the <tt>exact</tt> keyword is present, the result value of the
Dan Gohman57255802010-04-23 15:23:32 +0000[diff] [blame]3491 <tt>sdiv</tt> is a <a href="#trapvalues">trap value</a> if the result would
3492 be rounded or if overflow would occur.</p>
Dan Gohmanb07de442009-07-20 22:41:19 +0000[diff] [blame]3493
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3494<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3495<pre>
3496 &lt;result&gt; = sdiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3497</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3498
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3499</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3500
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3501<!-- _______________________________________________________________________ -->
3502<div class="doc_subsubsection"> <a name="i_fdiv">'<tt>fdiv</tt>'
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3503Instruction</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3504
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3505<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3506
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3507<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3508<pre>
Gabor Greif0f75ad02008-08-07 21:46:00 +0000[diff] [blame]3509 &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]3510</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3511
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3512<h5>Overview:</h5>
3513<p>The '<tt>fdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3514
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3515<h5>Arguments:</h5>
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]3516<p>The two arguments to the '<tt>fdiv</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3517 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3518 floating point values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3519
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3520<h5>Semantics:</h5>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3521<p>The value produced is the floating point quotient of the two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3522
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3523<h5>Example:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3524<pre>
3525 &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]3526</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3527
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3528</div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3529
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3530<!-- _______________________________________________________________________ -->
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3531<div class="doc_subsubsection"> <a name="i_urem">'<tt>urem</tt>' Instruction</a>
3532</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3533
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3534<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3535
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3536<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3537<pre>
3538 &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]3539</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3540
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3541<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3542<p>The '<tt>urem</tt>' instruction returns the remainder from the unsigned
3543 division of its two arguments.</p>
3544
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3545<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3546<p>The two arguments to the '<tt>urem</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3547 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3548 values. Both arguments must have identical types.</p>
3549
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3550<h5>Semantics:</h5>
3551<p>This instruction returns the unsigned integer <i>remainder</i> of a division.
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3552 This instruction always performs an unsigned division to get the
3553 remainder.</p>
3554
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3555<p>Note that unsigned integer remainder and signed integer remainder are
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3556 distinct operations; for signed integer remainder, use '<tt>srem</tt>'.</p>
3557
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3558<p>Taking the remainder of a division by zero leads to undefined behavior.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3559
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3560<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3561<pre>
3562 &lt;result&gt; = urem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3563</pre>
3564
3565</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3566
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3567<!-- _______________________________________________________________________ -->
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3568<div class="doc_subsubsection">
3569 <a name="i_srem">'<tt>srem</tt>' Instruction</a>
3570</div>
3571
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3572<div class="doc_text">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3573
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3574<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3575<pre>
Gabor Greif0f75ad02008-08-07 21:46:00 +0000[diff] [blame]3576 &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]3577</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3578
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3579<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3580<p>The '<tt>srem</tt>' instruction returns the remainder from the signed
3581 division of its two operands. This instruction can also take
3582 <a href="#t_vector">vector</a> versions of the values in which case the
3583 elements must be integers.</p>
Chris Lattnerb8f816e2008-01-04 04:33:49 +0000[diff] [blame]3584
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3585<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3586<p>The two arguments to the '<tt>srem</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3587 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3588 values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3589
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3590<h5>Semantics:</h5>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3591<p>This instruction returns the <i>remainder</i> of a division (where the result
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3592 has the same sign as the dividend, <tt>op1</tt>), not the <i>modulo</i>
3593 operator (where the result has the same sign as the divisor, <tt>op2</tt>) of
3594 a value. For more information about the difference,
3595 see <a href="http://mathforum.org/dr.math/problems/anne.4.28.99.html">The
3596 Math Forum</a>. For a table of how this is implemented in various languages,
3597 please see <a href="http://en.wikipedia.org/wiki/Modulo_operation">
3598 Wikipedia: modulo operation</a>.</p>
3599
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3600<p>Note that signed integer remainder and unsigned integer remainder are
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3601 distinct operations; for unsigned integer remainder, use '<tt>urem</tt>'.</p>
3602
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3603<p>Taking the remainder of a division by zero leads to undefined behavior.
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3604 Overflow also leads to undefined behavior; this is a rare case, but can
3605 occur, for example, by taking the remainder of a 32-bit division of
3606 -2147483648 by -1. (The remainder doesn't actually overflow, but this rule
3607 lets srem be implemented using instructions that return both the result of
3608 the division and the remainder.)</p>
3609
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3610<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3611<pre>
3612 &lt;result&gt; = srem 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_frem">'<tt>frem</tt>' Instruction</a> </div>
3620
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3621<div class="doc_text">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3622
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3623<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3624<pre>
3625 &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]3626</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3627
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3628<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3629<p>The '<tt>frem</tt>' instruction returns the remainder from the division of
3630 its two operands.</p>
3631
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3632<h5>Arguments:</h5>
3633<p>The two arguments to the '<tt>frem</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3634 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3635 floating point values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3636
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3637<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3638<p>This instruction returns the <i>remainder</i> of a division. The remainder
3639 has the same sign as the dividend.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3640
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3641<h5>Example:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3642<pre>
3643 &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]3644</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3645
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3646</div>
Robert Bocchino820bc75b2006-02-17 21:18:08 +0000[diff] [blame]3647
Reid Spencer2ab01932007-02-02 13:57:07 +0000[diff] [blame]3648<!-- ======================================================================= -->
3649<div class="doc_subsection"> <a name="bitwiseops">Bitwise Binary
3650Operations</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3651
Reid Spencer2ab01932007-02-02 13:57:07 +0000[diff] [blame]3652<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3653
3654<p>Bitwise binary operators are used to do various forms of bit-twiddling in a
3655 program. They are generally very efficient instructions and can commonly be
3656 strength reduced from other instructions. They require two operands of the
3657 same type, execute an operation on them, and produce a single value. The
3658 resulting value is the same type as its operands.</p>
3659
Reid Spencer2ab01932007-02-02 13:57:07 +0000[diff] [blame]3660</div>
3661
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3662<!-- _______________________________________________________________________ -->
3663<div class="doc_subsubsection"> <a name="i_shl">'<tt>shl</tt>'
3664Instruction</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3665
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3666<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3667
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3668<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3669<pre>
3670 &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]3671</pre>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]3672
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3673<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3674<p>The '<tt>shl</tt>' instruction returns the first operand shifted to the left
3675 a specified number of bits.</p>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]3676
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3677<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3678<p>Both arguments to the '<tt>shl</tt>' instruction must be the
3679 same <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3680 integer type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3681
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3682<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3683<p>The value produced is <tt>op1</tt> * 2<sup><tt>op2</tt></sup> mod
3684 2<sup>n</sup>, where <tt>n</tt> is the width of the result. If <tt>op2</tt>
3685 is (statically or dynamically) negative or equal to or larger than the number
3686 of bits in <tt>op1</tt>, the result is undefined. If the arguments are
3687 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
3688 shift amount in <tt>op2</tt>.</p>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]3689
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3690<h5>Example:</h5>
3691<pre>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3692 &lt;result&gt; = shl i32 4, %var <i>; yields {i32}: 4 &lt;&lt; %var</i>
3693 &lt;result&gt; = shl i32 4, 2 <i>; yields {i32}: 16</i>
3694 &lt;result&gt; = shl i32 1, 10 <i>; yields {i32}: 1024</i>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]3695 &lt;result&gt; = shl i32 1, 32 <i>; undefined</i>
Mon P Wang4dd832d2008-12-09 05:46:39 +0000[diff] [blame]3696 &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]3697</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3698
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3699</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3700
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3701<!-- _______________________________________________________________________ -->
3702<div class="doc_subsubsection"> <a name="i_lshr">'<tt>lshr</tt>'
3703Instruction</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3704
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3705<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3706
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3707<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3708<pre>
3709 &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]3710</pre>
3711
3712<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3713<p>The '<tt>lshr</tt>' instruction (logical shift right) returns the first
3714 operand shifted to the right a specified number of bits with zero fill.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3715
3716<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3717<p>Both arguments to the '<tt>lshr</tt>' instruction must be the same
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3718 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3719 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3720
3721<h5>Semantics:</h5>
3722<p>This instruction always performs a logical shift right operation. The most
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3723 significant bits of the result will be filled with zero bits after the shift.
3724 If <tt>op2</tt> is (statically or dynamically) equal to or larger than the
3725 number of bits in <tt>op1</tt>, the result is undefined. If the arguments are
3726 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
3727 shift amount in <tt>op2</tt>.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3728
3729<h5>Example:</h5>
3730<pre>
3731 &lt;result&gt; = lshr i32 4, 1 <i>; yields {i32}:result = 2</i>
3732 &lt;result&gt; = lshr i32 4, 2 <i>; yields {i32}:result = 1</i>
3733 &lt;result&gt; = lshr i8 4, 3 <i>; yields {i8}:result = 0</i>
3734 &lt;result&gt; = lshr i8 -2, 1 <i>; yields {i8}:result = 0x7FFFFFFF </i>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]3735 &lt;result&gt; = lshr i32 1, 32 <i>; undefined</i>
Mon P Wang4dd832d2008-12-09 05:46:39 +0000[diff] [blame]3736 &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]3737</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3738
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3739</div>
3740
Reid Spencer2ab01932007-02-02 13:57:07 +0000[diff] [blame]3741<!-- _______________________________________________________________________ -->
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3742<div class="doc_subsubsection"> <a name="i_ashr">'<tt>ashr</tt>'
3743Instruction</a> </div>
3744<div class="doc_text">
3745
3746<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3747<pre>
3748 &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]3749</pre>
3750
3751<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3752<p>The '<tt>ashr</tt>' instruction (arithmetic shift right) returns the first
3753 operand shifted to the right a specified number of bits with sign
3754 extension.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3755
3756<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3757<p>Both arguments to the '<tt>ashr</tt>' instruction must be the same
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3758 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3759 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3760
3761<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3762<p>This instruction always performs an arithmetic shift right operation, The
3763 most significant bits of the result will be filled with the sign bit
3764 of <tt>op1</tt>. If <tt>op2</tt> is (statically or dynamically) equal to or
3765 larger than the number of bits in <tt>op1</tt>, the result is undefined. If
3766 the arguments are vectors, each vector element of <tt>op1</tt> is shifted by
3767 the corresponding shift amount in <tt>op2</tt>.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3768
3769<h5>Example:</h5>
3770<pre>
3771 &lt;result&gt; = ashr i32 4, 1 <i>; yields {i32}:result = 2</i>
3772 &lt;result&gt; = ashr i32 4, 2 <i>; yields {i32}:result = 1</i>
3773 &lt;result&gt; = ashr i8 4, 3 <i>; yields {i8}:result = 0</i>
3774 &lt;result&gt; = ashr i8 -2, 1 <i>; yields {i8}:result = -1</i>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]3775 &lt;result&gt; = ashr i32 1, 32 <i>; undefined</i>
Mon P Wang4dd832d2008-12-09 05:46:39 +0000[diff] [blame]3776 &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]3777</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3778
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3779</div>
3780
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3781<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3782<div class="doc_subsubsection"> <a name="i_and">'<tt>and</tt>'
3783Instruction</a> </div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3784
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3785<div class="doc_text">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3786
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3787<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3788<pre>
Gabor Greif0f75ad02008-08-07 21:46:00 +0000[diff] [blame]3789 &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]3790</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3791
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3792<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3793<p>The '<tt>and</tt>' instruction returns the bitwise logical and of its two
3794 operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3795
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3796<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3797<p>The two arguments to the '<tt>and</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3798 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3799 values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3800
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3801<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3802<p>The truth table used for the '<tt>and</tt>' instruction is:</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3803
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3804<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3805 <tbody>
3806 <tr>
3807 <td>In0</td>
3808 <td>In1</td>
3809 <td>Out</td>
3810 </tr>
3811 <tr>
3812 <td>0</td>
3813 <td>0</td>
3814 <td>0</td>
3815 </tr>
3816 <tr>
3817 <td>0</td>
3818 <td>1</td>
3819 <td>0</td>
3820 </tr>
3821 <tr>
3822 <td>1</td>
3823 <td>0</td>
3824 <td>0</td>
3825 </tr>
3826 <tr>
3827 <td>1</td>
3828 <td>1</td>
3829 <td>1</td>
3830 </tr>
3831 </tbody>
3832</table>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3833
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3834<h5>Example:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3835<pre>
3836 &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]3837 &lt;result&gt; = and i32 15, 40 <i>; yields {i32}:result = 8</i>
3838 &lt;result&gt; = and i32 4, 8 <i>; yields {i32}:result = 0</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3839</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3840</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3841<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3842<div class="doc_subsubsection"> <a name="i_or">'<tt>or</tt>' Instruction</a> </div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3843
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3844<div class="doc_text">
3845
3846<h5>Syntax:</h5>
3847<pre>
3848 &lt;result&gt; = or &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3849</pre>
3850
3851<h5>Overview:</h5>
3852<p>The '<tt>or</tt>' instruction returns the bitwise logical inclusive or of its
3853 two operands.</p>
3854
3855<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3856<p>The two arguments to the '<tt>or</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3857 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3858 values. Both arguments must have identical types.</p>
3859
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3860<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3861<p>The truth table used for the '<tt>or</tt>' instruction is:</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3862
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3863<table border="1" cellspacing="0" cellpadding="4">
3864 <tbody>
3865 <tr>
3866 <td>In0</td>
3867 <td>In1</td>
3868 <td>Out</td>
3869 </tr>
3870 <tr>
3871 <td>0</td>
3872 <td>0</td>
3873 <td>0</td>
3874 </tr>
3875 <tr>
3876 <td>0</td>
3877 <td>1</td>
3878 <td>1</td>
3879 </tr>
3880 <tr>
3881 <td>1</td>
3882 <td>0</td>
3883 <td>1</td>
3884 </tr>
3885 <tr>
3886 <td>1</td>
3887 <td>1</td>
3888 <td>1</td>
3889 </tr>
3890 </tbody>
3891</table>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3892
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3893<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3894<pre>
3895 &lt;result&gt; = or i32 4, %var <i>; yields {i32}:result = 4 | %var</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3896 &lt;result&gt; = or i32 15, 40 <i>; yields {i32}:result = 47</i>
3897 &lt;result&gt; = or i32 4, 8 <i>; yields {i32}:result = 12</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3898</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3899
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3900</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3901
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3902<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3903<div class="doc_subsubsection"> <a name="i_xor">'<tt>xor</tt>'
3904Instruction</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3905
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3906<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3907
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3908<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3909<pre>
3910 &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]3911</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3912
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3913<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3914<p>The '<tt>xor</tt>' instruction returns the bitwise logical exclusive or of
3915 its two operands. The <tt>xor</tt> is used to implement the "one's
3916 complement" operation, which is the "~" operator in C.</p>
3917
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3918<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3919<p>The two arguments to the '<tt>xor</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3920 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3921 values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3922
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3923<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3924<p>The truth table used for the '<tt>xor</tt>' instruction is:</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3925
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3926<table border="1" cellspacing="0" cellpadding="4">
3927 <tbody>
3928 <tr>
3929 <td>In0</td>
3930 <td>In1</td>
3931 <td>Out</td>
3932 </tr>
3933 <tr>
3934 <td>0</td>
3935 <td>0</td>
3936 <td>0</td>
3937 </tr>
3938 <tr>
3939 <td>0</td>
3940 <td>1</td>
3941 <td>1</td>
3942 </tr>
3943 <tr>
3944 <td>1</td>
3945 <td>0</td>
3946 <td>1</td>
3947 </tr>
3948 <tr>
3949 <td>1</td>
3950 <td>1</td>
3951 <td>0</td>
3952 </tr>
3953 </tbody>
3954</table>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3955
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3956<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3957<pre>
3958 &lt;result&gt; = xor i32 4, %var <i>; yields {i32}:result = 4 ^ %var</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3959 &lt;result&gt; = xor i32 15, 40 <i>; yields {i32}:result = 39</i>
3960 &lt;result&gt; = xor i32 4, 8 <i>; yields {i32}:result = 12</i>
3961 &lt;result&gt; = xor i32 %V, -1 <i>; yields {i32}:result = ~%V</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3962</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3963
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3964</div>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3965
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3966<!-- ======================================================================= -->
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3967<div class="doc_subsection">
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]3968 <a name="vectorops">Vector Operations</a>
3969</div>
3970
3971<div class="doc_text">
3972
3973<p>LLVM supports several instructions to represent vector operations in a
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3974 target-independent manner. These instructions cover the element-access and
3975 vector-specific operations needed to process vectors effectively. While LLVM
3976 does directly support these vector operations, many sophisticated algorithms
3977 will want to use target-specific intrinsics to take full advantage of a
3978 specific target.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]3979
3980</div>
3981
3982<!-- _______________________________________________________________________ -->
3983<div class="doc_subsubsection">
3984 <a name="i_extractelement">'<tt>extractelement</tt>' Instruction</a>
3985</div>
3986
3987<div class="doc_text">
3988
3989<h5>Syntax:</h5>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]3990<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3991 &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]3992</pre>
3993
3994<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3995<p>The '<tt>extractelement</tt>' instruction extracts a single scalar element
3996 from a vector at a specified index.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]3997
3998
3999<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4000<p>The first operand of an '<tt>extractelement</tt>' instruction is a value
4001 of <a href="#t_vector">vector</a> type. The second operand is an index
4002 indicating the position from which to extract the element. The index may be
4003 a variable.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4004
4005<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4006<p>The result is a scalar of the same type as the element type of
4007 <tt>val</tt>. Its value is the value at position <tt>idx</tt> of
4008 <tt>val</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
4009 results are undefined.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4010
4011<h5>Example:</h5>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4012<pre>
Gabor Greif03ab4dc2009-10-28 13:14:50 +0000[diff] [blame]4013 &lt;result&gt; = extractelement &lt;4 x i32&gt; %vec, i32 0 <i>; yields i32</i>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4014</pre>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4015
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4016</div>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4017
4018<!-- _______________________________________________________________________ -->
4019<div class="doc_subsubsection">
4020 <a name="i_insertelement">'<tt>insertelement</tt>' Instruction</a>
4021</div>
4022
4023<div class="doc_text">
4024
4025<h5>Syntax:</h5>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4026<pre>
Dan Gohman43ba0672008-05-12 23:38:42 +0000[diff] [blame]4027 &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]4028</pre>
4029
4030<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4031<p>The '<tt>insertelement</tt>' instruction inserts a scalar element into a
4032 vector at a specified index.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4033
4034<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4035<p>The first operand of an '<tt>insertelement</tt>' instruction is a value
4036 of <a href="#t_vector">vector</a> type. The second operand is a scalar value
4037 whose type must equal the element type of the first operand. The third
4038 operand is an index indicating the position at which to insert the value.
4039 The index may be a variable.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4040
4041<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4042<p>The result is a vector of the same type as <tt>val</tt>. Its element values
4043 are those of <tt>val</tt> except at position <tt>idx</tt>, where it gets the
4044 value <tt>elt</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
4045 results are undefined.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4046
4047<h5>Example:</h5>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4048<pre>
Gabor Greif03ab4dc2009-10-28 13:14:50 +0000[diff] [blame]4049 &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]4050</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4051
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4052</div>
4053
4054<!-- _______________________________________________________________________ -->
4055<div class="doc_subsubsection">
4056 <a name="i_shufflevector">'<tt>shufflevector</tt>' Instruction</a>
4057</div>
4058
4059<div class="doc_text">
4060
4061<h5>Syntax:</h5>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4062<pre>
Mon P Wang25f01062008-11-10 04:46:22 +0000[diff] [blame]4063 &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]4064</pre>
4065
4066<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4067<p>The '<tt>shufflevector</tt>' instruction constructs a permutation of elements
4068 from two input vectors, returning a vector with the same element type as the
4069 input and length that is the same as the shuffle mask.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4070
4071<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4072<p>The first two operands of a '<tt>shufflevector</tt>' instruction are vectors
4073 with types that match each other. The third argument is a shuffle mask whose
4074 element type is always 'i32'. The result of the instruction is a vector
4075 whose length is the same as the shuffle mask and whose element type is the
4076 same as the element type of the first two operands.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4077
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4078<p>The shuffle mask operand is required to be a constant vector with either
4079 constant integer or undef values.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4080
4081<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4082<p>The elements of the two input vectors are numbered from left to right across
4083 both of the vectors. The shuffle mask operand specifies, for each element of
4084 the result vector, which element of the two input vectors the result element
4085 gets. The element selector may be undef (meaning "don't care") and the
4086 second operand may be undef if performing a shuffle from only one vector.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4087
4088<h5>Example:</h5>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4089<pre>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4090 &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]4091 &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]4092 &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]4093 &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]4094 &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]4095 &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]4096 &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]4097 &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]4098</pre>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4099
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4100</div>
Tanya Lattnerb138bbe2006-04-14 19:24:33 +0000[diff] [blame]4101
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4102<!-- ======================================================================= -->
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4103<div class="doc_subsection">
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4104 <a name="aggregateops">Aggregate Operations</a>
4105</div>
4106
4107<div class="doc_text">
4108
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]4109<p>LLVM supports several instructions for working with
4110 <a href="#t_aggregate">aggregate</a> values.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4111
4112</div>
4113
4114<!-- _______________________________________________________________________ -->
4115<div class="doc_subsubsection">
4116 <a name="i_extractvalue">'<tt>extractvalue</tt>' Instruction</a>
4117</div>
4118
4119<div class="doc_text">
4120
4121<h5>Syntax:</h5>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4122<pre>
4123 &lt;result&gt; = extractvalue &lt;aggregate type&gt; &lt;val&gt;, &lt;idx&gt;{, &lt;idx&gt;}*
4124</pre>
4125
4126<h5>Overview:</h5>
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]4127<p>The '<tt>extractvalue</tt>' instruction extracts the value of a member field
4128 from an <a href="#t_aggregate">aggregate</a> value.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4129
4130<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4131<p>The first operand of an '<tt>extractvalue</tt>' instruction is a value
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]4132 of <a href="#t_struct">struct</a>, <a href="#t_union">union</a> or
4133 <a href="#t_array">array</a> type. The operands are constant indices to
4134 specify which value to extract in a similar manner as indices in a
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4135 '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4136
4137<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4138<p>The result is the value at the position in the aggregate specified by the
4139 index operands.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4140
4141<h5>Example:</h5>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4142<pre>
Gabor Greif03ab4dc2009-10-28 13:14:50 +0000[diff] [blame]4143 &lt;result&gt; = extractvalue {i32, float} %agg, 0 <i>; yields i32</i>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4144</pre>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4145
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4146</div>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4147
4148<!-- _______________________________________________________________________ -->
4149<div class="doc_subsubsection">
4150 <a name="i_insertvalue">'<tt>insertvalue</tt>' Instruction</a>
4151</div>
4152
4153<div class="doc_text">
4154
4155<h5>Syntax:</h5>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4156<pre>
Jeffrey Yasskinf991bbb2010-01-11 19:19:26 +0000[diff] [blame]4157 &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]4158</pre>
4159
4160<h5>Overview:</h5>
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]4161<p>The '<tt>insertvalue</tt>' instruction inserts a value into a member field
4162 in an <a href="#t_aggregate">aggregate</a> value.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4163
4164<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4165<p>The first operand of an '<tt>insertvalue</tt>' instruction is a value
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]4166 of <a href="#t_struct">struct</a>, <a href="#t_union">union</a> or
4167 <a href="#t_array">array</a> type. The second operand is a first-class
4168 value to insert. The following operands are constant indices indicating
4169 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]4170 '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction. The
4171 value to insert must have the same type as the value identified by the
4172 indices.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4173
4174<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4175<p>The result is an aggregate of the same type as <tt>val</tt>. Its value is
4176 that of <tt>val</tt> except that the value at the position specified by the
4177 indices is that of <tt>elt</tt>.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4178
4179<h5>Example:</h5>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4180<pre>
Jeffrey Yasskinf991bbb2010-01-11 19:19:26 +0000[diff] [blame]4181 %agg1 = insertvalue {i32, float} undef, i32 1, 0 <i>; yields {i32 1, float undef}</i>
4182 %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]4183</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4184
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4185</div>
4186
4187
4188<!-- ======================================================================= -->
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4189<div class="doc_subsection">
Chris Lattner6ab66722006-08-15 00:45:58 +0000[diff] [blame]4190 <a name="memoryops">Memory Access and Addressing Operations</a>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4191</div>
4192
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4193<div class="doc_text">
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4194
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4195<p>A key design point of an SSA-based representation is how it represents
4196 memory. In LLVM, no memory locations are in SSA form, which makes things
Victor Hernandeza70c6df2009-10-26 23:44:29 +0000[diff] [blame]4197 very simple. This section describes how to read, write, and allocate
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4198 memory in LLVM.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4199
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4200</div>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4201
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4202<!-- _______________________________________________________________________ -->
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4203<div class="doc_subsubsection">
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4204 <a name="i_alloca">'<tt>alloca</tt>' Instruction</a>
4205</div>
4206
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4207<div class="doc_text">
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4208
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4209<h5>Syntax:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4210<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4211 &lt;result&gt; = alloca &lt;type&gt;[, i32 &lt;NumElements&gt;][, align &lt;alignment&gt;] <i>; yields {type*}:result</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4212</pre>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4213
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4214<h5>Overview:</h5>
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]4215<p>The '<tt>alloca</tt>' instruction allocates memory on the stack frame of the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4216 currently executing function, to be automatically released when this function
4217 returns to its caller. The object is always allocated in the generic address
4218 space (address space zero).</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4219
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4220<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4221<p>The '<tt>alloca</tt>' instruction
4222 allocates <tt>sizeof(&lt;type&gt;)*NumElements</tt> bytes of memory on the
4223 runtime stack, returning a pointer of the appropriate type to the program.
4224 If "NumElements" is specified, it is the number of elements allocated,
4225 otherwise "NumElements" is defaulted to be one. If a constant alignment is
4226 specified, the value result of the allocation is guaranteed to be aligned to
4227 at least that boundary. If not specified, or if zero, the target can choose
4228 to align the allocation on any convenient boundary compatible with the
4229 type.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4230
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4231<p>'<tt>type</tt>' may be any sized type.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4232
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4233<h5>Semantics:</h5>
Bill Wendling9ee6a312009-05-08 20:49:29 +0000[diff] [blame]4234<p>Memory is allocated; a pointer is returned. The operation is undefined if
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4235 there is insufficient stack space for the allocation. '<tt>alloca</tt>'d
4236 memory is automatically released when the function returns. The
4237 '<tt>alloca</tt>' instruction is commonly used to represent automatic
4238 variables that must have an address available. When the function returns
4239 (either with the <tt><a href="#i_ret">ret</a></tt>
4240 or <tt><a href="#i_unwind">unwind</a></tt> instructions), the memory is
4241 reclaimed. Allocating zero bytes is legal, but the result is undefined.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4242
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4243<h5>Example:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4244<pre>
Dan Gohman7a5acb52009-01-04 23:49:44 +0000[diff] [blame]4245 %ptr = alloca i32 <i>; yields {i32*}:ptr</i>
4246 %ptr = alloca i32, i32 4 <i>; yields {i32*}:ptr</i>
4247 %ptr = alloca i32, i32 4, align 1024 <i>; yields {i32*}:ptr</i>
4248 %ptr = alloca i32, align 1024 <i>; yields {i32*}:ptr</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4249</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4250
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4251</div>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4252
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4253<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]4254<div class="doc_subsubsection"> <a name="i_load">'<tt>load</tt>'
4255Instruction</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4256
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4257<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4258
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4259<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4260<pre>
Bill Wendlingbc4024f2010-02-25 21:23:24 +0000[diff] [blame]4261 &lt;result&gt; = load &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;][, !nontemporal !&lt;index&gt;]
4262 &lt;result&gt; = volatile load &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;][, !nontemporal !&lt;index&gt;]
4263 !&lt;index&gt; = !{ i32 1 }
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4264</pre>
4265
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4266<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4267<p>The '<tt>load</tt>' instruction is used to read from memory.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4268
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4269<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4270<p>The argument to the '<tt>load</tt>' instruction specifies the memory address
4271 from which to load. The pointer must point to
4272 a <a href="#t_firstclass">first class</a> type. If the <tt>load</tt> is
4273 marked as <tt>volatile</tt>, then the optimizer is not allowed to modify the
Jeffrey Yasskin5d284ae2010-04-26 21:21:24 +0000[diff] [blame]4274 number or order of execution of this <tt>load</tt> with other <a
4275 href="#volatile">volatile operations</a>.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4276
Bill Wendlingbc4024f2010-02-25 21:23:24 +0000[diff] [blame]4277<p>The optional constant <tt>align</tt> argument specifies the alignment of the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4278 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]4279 omitted <tt>align</tt> argument means that the operation has the preferential
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4280 alignment for the target. It is the responsibility of the code emitter to
4281 ensure that the alignment information is correct. Overestimating the
Bill Wendlingbc4024f2010-02-25 21:23:24 +0000[diff] [blame]4282 alignment results in undefined behavior. Underestimating the alignment may
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4283 produce less efficient code. An alignment of 1 is always safe.</p>
4284
Bill Wendlingbc4024f2010-02-25 21:23:24 +0000[diff] [blame]4285<p>The optional <tt>!nontemporal</tt> metadata must reference a single
4286 metatadata name &lt;index&gt; corresponding to a metadata node with
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]4287 one <tt>i32</tt> entry of value 1. The existence of
Bill Wendlingbc4024f2010-02-25 21:23:24 +0000[diff] [blame]4288 the <tt>!nontemporal</tt> metatadata on the instruction tells the optimizer
4289 and code generator that this load is not expected to be reused in the cache.
4290 The code generator may select special instructions to save cache bandwidth,
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]4291 such as the <tt>MOVNT</tt> instruction on x86.</p>
David Greene9641d062010-02-16 20:50:18 +0000[diff] [blame]4292
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4293<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4294<p>The location of memory pointed to is loaded. If the value being loaded is of
4295 scalar type then the number of bytes read does not exceed the minimum number
4296 of bytes needed to hold all bits of the type. For example, loading an
4297 <tt>i24</tt> reads at most three bytes. When loading a value of a type like
4298 <tt>i20</tt> with a size that is not an integral number of bytes, the result
4299 is undefined if the value was not originally written using a store of the
4300 same type.</p>
4301
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4302<h5>Examples:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4303<pre>
4304 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
4305 <a href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4306 %val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4307</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4308
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4309</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4310
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4311<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]4312<div class="doc_subsubsection"> <a name="i_store">'<tt>store</tt>'
4313Instruction</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4314
Reid Spencera89fb182006-11-09 21:18:01 +0000[diff] [blame]4315<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4316
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4317<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4318<pre>
David Greene9641d062010-02-16 20:50:18 +0000[diff] [blame]4319 store &lt;ty&gt; &lt;value&gt;, &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;][, !nontemporal !<index>] <i>; yields {void}</i>
4320 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]4321</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4322
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4323<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4324<p>The '<tt>store</tt>' instruction is used to write to memory.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4325
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4326<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4327<p>There are two arguments to the '<tt>store</tt>' instruction: a value to store
4328 and an address at which to store it. The type of the
4329 '<tt>&lt;pointer&gt;</tt>' operand must be a pointer to
4330 the <a href="#t_firstclass">first class</a> type of the
Jeffrey Yasskin5d284ae2010-04-26 21:21:24 +0000[diff] [blame]4331 '<tt>&lt;value&gt;</tt>' operand. If the <tt>store</tt> is marked as
4332 <tt>volatile</tt>, then the optimizer is not allowed to modify the number or
4333 order of execution of this <tt>store</tt> with other <a
4334 href="#volatile">volatile operations</a>.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4335
4336<p>The optional constant "align" argument specifies the alignment of the
4337 operation (that is, the alignment of the memory address). A value of 0 or an
4338 omitted "align" argument means that the operation has the preferential
4339 alignment for the target. It is the responsibility of the code emitter to
4340 ensure that the alignment information is correct. Overestimating the
4341 alignment results in an undefined behavior. Underestimating the alignment may
4342 produce less efficient code. An alignment of 1 is always safe.</p>
4343
David Greene9641d062010-02-16 20:50:18 +0000[diff] [blame]4344<p>The optional !nontemporal metadata must reference a single metatadata
4345 name <index> corresponding to a metadata node with one i32 entry of
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]4346 value 1. The existence of the !nontemporal metatadata on the
David Greene9641d062010-02-16 20:50:18 +0000[diff] [blame]4347 instruction tells the optimizer and code generator that this load is
4348 not expected to be reused in the cache. The code generator may
4349 select special instructions to save cache bandwidth, such as the
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]4350 MOVNT instruction on x86.</p>
David Greene9641d062010-02-16 20:50:18 +0000[diff] [blame]4351
4352
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]4353<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4354<p>The contents of memory are updated to contain '<tt>&lt;value&gt;</tt>' at the
4355 location specified by the '<tt>&lt;pointer&gt;</tt>' operand. If
4356 '<tt>&lt;value&gt;</tt>' is of scalar type then the number of bytes written
4357 does not exceed the minimum number of bytes needed to hold all bits of the
4358 type. For example, storing an <tt>i24</tt> writes at most three bytes. When
4359 writing a value of a type like <tt>i20</tt> with a size that is not an
4360 integral number of bytes, it is unspecified what happens to the extra bits
4361 that do not belong to the type, but they will typically be overwritten.</p>
4362
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4363<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4364<pre>
4365 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Bill Wendling8830ffe2007-10-22 05:10:05 +0000[diff] [blame]4366 store i32 3, i32* %ptr <i>; yields {void}</i>
4367 %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]4368</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4369
Reid Spencer443460a2006-11-09 21:15:49 +0000[diff] [blame]4370</div>
4371
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4372<!-- _______________________________________________________________________ -->
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4373<div class="doc_subsubsection">
4374 <a name="i_getelementptr">'<tt>getelementptr</tt>' Instruction</a>
4375</div>
4376
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4377<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4378
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]4379<h5>Syntax:</h5>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4380<pre>
Matthijs Kooijman0e268272008-10-13 13:44:15 +0000[diff] [blame]4381 &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]4382 &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]4383</pre>
4384
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]4385<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4386<p>The '<tt>getelementptr</tt>' instruction is used to get the address of a
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]4387 subelement of an <a href="#t_aggregate">aggregate</a> data structure.
4388 It performs address calculation only and does not access memory.</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4389
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]4390<h5>Arguments:</h5>
Matthijs Kooijman0e268272008-10-13 13:44:15 +0000[diff] [blame]4391<p>The first argument is always a pointer, and forms the basis of the
Chris Lattnera40b9122009-07-29 06:44:13 +0000[diff] [blame]4392 calculation. The remaining arguments are indices that indicate which of the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4393 elements of the aggregate object are indexed. The interpretation of each
4394 index is dependent on the type being indexed into. The first index always
4395 indexes the pointer value given as the first argument, the second index
4396 indexes a value of the type pointed to (not necessarily the value directly
4397 pointed to, since the first index can be non-zero), etc. The first type
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]4398 indexed into must be a pointer value, subsequent types can be arrays,
4399 vectors, structs and unions. Note that subsequent types being indexed into
4400 can never be pointers, since that would require loading the pointer before
4401 continuing calculation.</p>
Matthijs Kooijman0e268272008-10-13 13:44:15 +0000[diff] [blame]4402
4403<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]4404 When indexing into a (optionally packed) structure or union, only <tt>i32</tt>
4405 integer <b>constants</b> are allowed. When indexing into an array, pointer
4406 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]4407 constant.</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4408
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4409<p>For example, let's consider a C code fragment and how it gets compiled to
4410 LLVM:</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4411
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]4412<div class="doc_code">
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4413<pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]4414struct RT {
4415 char A;
Chris Lattnera446f1b2007-05-29 15:43:56 +0000[diff] [blame]4416 int B[10][20];
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]4417 char C;
4418};
4419struct ST {
Chris Lattnera446f1b2007-05-29 15:43:56 +0000[diff] [blame]4420 int X;
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]4421 double Y;
4422 struct RT Z;
4423};
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4424
Chris Lattnera446f1b2007-05-29 15:43:56 +0000[diff] [blame]4425int *foo(struct ST *s) {
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]4426 return &amp;s[1].Z.B[5][13];
4427}
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4428</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]4429</div>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4430
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4431<p>The LLVM code generated by the GCC frontend is:</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4432
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]4433<div class="doc_code">
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4434<pre>
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]4435%RT = <a href="#namedtypes">type</a> { i8 , [10 x [20 x i32]], i8 }
4436%ST = <a href="#namedtypes">type</a> { i32, double, %RT }
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4437
Dan Gohman6b867702009-07-25 02:23:48 +0000[diff] [blame]4438define i32* @foo(%ST* %s) {
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]4439entry:
4440 %reg = getelementptr %ST* %s, i32 1, i32 2, i32 1, i32 5, i32 13
4441 ret i32* %reg
4442}
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4443</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]4444</div>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4445
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]4446<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4447<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]4448 type, which is a pointer, yielding a '<tt>%ST</tt>' = '<tt>{ i32, double, %RT
4449 }</tt>' type, a structure. The second index indexes into the third element
4450 of the structure, yielding a '<tt>%RT</tt>' = '<tt>{ i8 , [10 x [20 x i32]],
4451 i8 }</tt>' type, another structure. The third index indexes into the second
4452 element of the structure, yielding a '<tt>[10 x [20 x i32]]</tt>' type, an
4453 array. The two dimensions of the array are subscripted into, yielding an
4454 '<tt>i32</tt>' type. The '<tt>getelementptr</tt>' instruction returns a
4455 pointer to this element, thus computing a value of '<tt>i32*</tt>' type.</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4456
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4457<p>Note that it is perfectly legal to index partially through a structure,
4458 returning a pointer to an inner element. Because of this, the LLVM code for
4459 the given testcase is equivalent to:</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4460
4461<pre>
Dan Gohman6b867702009-07-25 02:23:48 +0000[diff] [blame]4462 define i32* @foo(%ST* %s) {
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4463 %t1 = getelementptr %ST* %s, i32 1 <i>; yields %ST*:%t1</i>
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]4464 %t2 = getelementptr %ST* %t1, i32 0, i32 2 <i>; yields %RT*:%t2</i>
4465 %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]4466 %t4 = getelementptr [10 x [20 x i32]]* %t3, i32 0, i32 5 <i>; yields [20 x i32]*:%t4</i>
4467 %t5 = getelementptr [20 x i32]* %t4, i32 0, i32 13 <i>; yields i32*:%t5</i>
4468 ret i32* %t5
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4469 }
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]4470</pre>
Chris Lattnerc0ad71e2005-06-24 17:22:57 +0000[diff] [blame]4471
Dan Gohman1639c392009-07-27 21:53:46 +0000[diff] [blame]4472<p>If the <tt>inbounds</tt> keyword is present, the result value of the
Dan Gohman57255802010-04-23 15:23:32 +0000[diff] [blame]4473 <tt>getelementptr</tt> is a <a href="#trapvalues">trap value</a> if the
4474 base pointer is not an <i>in bounds</i> address of an allocated object,
4475 or if any of the addresses that would be formed by successive addition of
4476 the offsets implied by the indices to the base address with infinitely
4477 precise arithmetic are not an <i>in bounds</i> address of that allocated
4478 object. The <i>in bounds</i> addresses for an allocated object are all
4479 the addresses that point into the object, plus the address one byte past
4480 the end.</p>
Dan Gohman1639c392009-07-27 21:53:46 +0000[diff] [blame]4481
4482<p>If the <tt>inbounds</tt> keyword is not present, the offsets are added to
4483 the base address with silently-wrapping two's complement arithmetic, and
4484 the result value of the <tt>getelementptr</tt> may be outside the object
4485 pointed to by the base pointer. The result value may not necessarily be
4486 used to access memory though, even if it happens to point into allocated
4487 storage. See the <a href="#pointeraliasing">Pointer Aliasing Rules</a>
4488 section for more information.</p>
4489
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4490<p>The getelementptr instruction is often confusing. For some more insight into
4491 how it works, see <a href="GetElementPtr.html">the getelementptr FAQ</a>.</p>
Chris Lattner6ab66722006-08-15 00:45:58 +0000[diff] [blame]4492
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]4493<h5>Example:</h5>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4494<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4495 <i>; yields [12 x i8]*:aptr</i>
Matthijs Kooijman0e268272008-10-13 13:44:15 +0000[diff] [blame]4496 %aptr = getelementptr {i32, [12 x i8]}* %saptr, i64 0, i32 1
4497 <i>; yields i8*:vptr</i>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]4498 %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]4499 <i>; yields i8*:eptr</i>
4500 %eptr = getelementptr [12 x i8]* %aptr, i64 0, i32 1
Sanjiv Gupta0c155e62009-04-25 07:27:44 +0000[diff] [blame]4501 <i>; yields i32*:iptr</i>
Sanjiv Gupta77abea02009-04-24 16:38:13 +0000[diff] [blame]4502 %iptr = getelementptr [10 x i32]* @arr, i16 0, i16 0
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4503</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4504
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4505</div>
Reid Spencer443460a2006-11-09 21:15:49 +0000[diff] [blame]4506
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4507<!-- ======================================================================= -->
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]4508<div class="doc_subsection"> <a name="convertops">Conversion Operations</a>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4509</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4510
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4511<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4512
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]4513<p>The instructions in this category are the conversion instructions (casting)
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4514 which all take a single operand and a type. They perform various bit
4515 conversions on the operand.</p>
4516
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4517</div>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]4518
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]4519<!-- _______________________________________________________________________ -->
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]4520<div class="doc_subsubsection">
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4521 <a name="i_trunc">'<tt>trunc .. to</tt>' Instruction</a>
4522</div>
4523<div class="doc_text">
4524
4525<h5>Syntax:</h5>
4526<pre>
4527 &lt;result&gt; = trunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4528</pre>
4529
4530<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4531<p>The '<tt>trunc</tt>' instruction truncates its operand to the
4532 type <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4533
4534<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4535<p>The '<tt>trunc</tt>' instruction takes a <tt>value</tt> to trunc, which must
4536 be an <a href="#t_integer">integer</a> type, and a type that specifies the
4537 size and type of the result, which must be
4538 an <a href="#t_integer">integer</a> type. The bit size of <tt>value</tt> must
4539 be larger than the bit size of <tt>ty2</tt>. Equal sized types are not
4540 allowed.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4541
4542<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4543<p>The '<tt>trunc</tt>' instruction truncates the high order bits
4544 in <tt>value</tt> and converts the remaining bits to <tt>ty2</tt>. Since the
4545 source size must be larger than the destination size, <tt>trunc</tt> cannot
4546 be a <i>no-op cast</i>. It will always truncate bits.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4547
4548<h5>Example:</h5>
4549<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4550 %X = trunc i32 257 to i8 <i>; yields i8:1</i>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]4551 %Y = trunc i32 123 to i1 <i>; yields i1:true</i>
Gabor Greiff50fd572009-10-28 09:21:30 +0000[diff] [blame]4552 %Z = trunc i32 122 to i1 <i>; yields i1:false</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4553</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4554
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4555</div>
4556
4557<!-- _______________________________________________________________________ -->
4558<div class="doc_subsubsection">
4559 <a name="i_zext">'<tt>zext .. to</tt>' Instruction</a>
4560</div>
4561<div class="doc_text">
4562
4563<h5>Syntax:</h5>
4564<pre>
4565 &lt;result&gt; = zext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4566</pre>
4567
4568<h5>Overview:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4569<p>The '<tt>zext</tt>' instruction zero extends its operand to type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4570 <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4571
4572
4573<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4574<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]4575 <a href="#t_integer">integer</a> type, and a type to cast it to, which must
4576 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]4577 <tt>value</tt> must be smaller than the bit size of the destination type,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4578 <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4579
4580<h5>Semantics:</h5>
4581<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]4582 bits until it reaches the size of the destination type, <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4583
Reid Spencer07c9c682007-01-12 15:46:11 +0000[diff] [blame]4584<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]4585
4586<h5>Example:</h5>
4587<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4588 %X = zext i32 257 to i64 <i>; yields i64:257</i>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]4589 %Y = zext i1 true to i32 <i>; yields i32:1</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4590</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4591
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4592</div>
4593
4594<!-- _______________________________________________________________________ -->
4595<div class="doc_subsubsection">
4596 <a name="i_sext">'<tt>sext .. to</tt>' Instruction</a>
4597</div>
4598<div class="doc_text">
4599
4600<h5>Syntax:</h5>
4601<pre>
4602 &lt;result&gt; = sext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4603</pre>
4604
4605<h5>Overview:</h5>
4606<p>The '<tt>sext</tt>' sign extends <tt>value</tt> to the type <tt>ty2</tt>.</p>
4607
4608<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4609<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]4610 <a href="#t_integer">integer</a> type, and a type to cast it to, which must
4611 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]4612 <tt>value</tt> must be smaller than the bit size of the destination type,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4613 <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4614
4615<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4616<p>The '<tt>sext</tt>' instruction performs a sign extension by copying the sign
4617 bit (highest order bit) of the <tt>value</tt> until it reaches the bit size
4618 of the type <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4619
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]4620<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]4621
4622<h5>Example:</h5>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4623<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4624 %X = sext i8 -1 to i16 <i>; yields i16 :65535</i>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]4625 %Y = sext i1 true to i32 <i>; yields i32:-1</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4626</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4627
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4628</div>
4629
4630<!-- _______________________________________________________________________ -->
4631<div class="doc_subsubsection">
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]4632 <a name="i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a>
4633</div>
4634
4635<div class="doc_text">
4636
4637<h5>Syntax:</h5>
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]4638<pre>
4639 &lt;result&gt; = fptrunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4640</pre>
4641
4642<h5>Overview:</h5>
4643<p>The '<tt>fptrunc</tt>' instruction truncates <tt>value</tt> to type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4644 <tt>ty2</tt>.</p>
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]4645
4646<h5>Arguments:</h5>
4647<p>The '<tt>fptrunc</tt>' instruction takes a <a href="#t_floating">floating
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4648 point</a> value to cast and a <a href="#t_floating">floating point</a> type
4649 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]4650 <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]4651 <i>no-op cast</i>.</p>
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]4652
4653<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4654<p>The '<tt>fptrunc</tt>' instruction truncates a <tt>value</tt> from a larger
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4655 <a href="#t_floating">floating point</a> type to a smaller
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4656 <a href="#t_floating">floating point</a> type. If the value cannot fit
4657 within the destination type, <tt>ty2</tt>, then the results are
4658 undefined.</p>
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]4659
4660<h5>Example:</h5>
4661<pre>
4662 %X = fptrunc double 123.0 to float <i>; yields float:123.0</i>
4663 %Y = fptrunc double 1.0E+300 to float <i>; yields undefined</i>
4664</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4665
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]4666</div>
4667
4668<!-- _______________________________________________________________________ -->
4669<div class="doc_subsubsection">
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4670 <a name="i_fpext">'<tt>fpext .. to</tt>' Instruction</a>
4671</div>
4672<div class="doc_text">
4673
4674<h5>Syntax:</h5>
4675<pre>
4676 &lt;result&gt; = fpext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4677</pre>
4678
4679<h5>Overview:</h5>
4680<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]4681 floating point value.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4682
4683<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4684<p>The '<tt>fpext</tt>' instruction takes a
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4685 <a href="#t_floating">floating point</a> <tt>value</tt> to cast, and
4686 a <a href="#t_floating">floating point</a> type to cast it to. The source
4687 type must be smaller than the destination type.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4688
4689<h5>Semantics:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]4690<p>The '<tt>fpext</tt>' instruction extends the <tt>value</tt> from a smaller
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4691 <a href="#t_floating">floating point</a> type to a larger
4692 <a href="#t_floating">floating point</a> type. The <tt>fpext</tt> cannot be
4693 used to make a <i>no-op cast</i> because it always changes bits. Use
4694 <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]4695
4696<h5>Example:</h5>
4697<pre>
4698 %X = fpext float 3.1415 to double <i>; yields double:3.1415</i>
4699 %Y = fpext float 1.0 to float <i>; yields float:1.0 (no-op)</i>
4700</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4701
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4702</div>
4703
4704<!-- _______________________________________________________________________ -->
4705<div class="doc_subsubsection">
Reid Spencer2eadb532007-01-21 00:29:26 +0000[diff] [blame]4706 <a name="i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4707</div>
4708<div class="doc_text">
4709
4710<h5>Syntax:</h5>
4711<pre>
Reid Spencer753163d2007-07-31 14:40:14 +0000[diff] [blame]4712 &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]4713</pre>
4714
4715<h5>Overview:</h5>
Reid Spencer753163d2007-07-31 14:40:14 +0000[diff] [blame]4716<p>The '<tt>fptoui</tt>' converts a floating point <tt>value</tt> to its
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4717 unsigned integer equivalent of type <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4718
4719<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4720<p>The '<tt>fptoui</tt>' instruction takes a value to cast, which must be a
4721 scalar or vector <a href="#t_floating">floating point</a> value, and a type
4722 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
4723 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
4724 vector integer type with the same number of elements as <tt>ty</tt></p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4725
4726<h5>Semantics:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4727<p>The '<tt>fptoui</tt>' instruction converts its
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4728 <a href="#t_floating">floating point</a> operand into the nearest (rounding
4729 towards zero) unsigned integer value. If the value cannot fit
4730 in <tt>ty2</tt>, the results are undefined.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4731
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4732<h5>Example:</h5>
4733<pre>
Reid Spencer753163d2007-07-31 14:40:14 +0000[diff] [blame]4734 %X = fptoui double 123.0 to i32 <i>; yields i32:123</i>
Chris Lattner5b95a172007-09-22 03:17:52 +0000[diff] [blame]4735 %Y = fptoui float 1.0E+300 to i1 <i>; yields undefined:1</i>
Gabor Greiff50fd572009-10-28 09:21:30 +0000[diff] [blame]4736 %Z = fptoui float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4737</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4738
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4739</div>
4740
4741<!-- _______________________________________________________________________ -->
4742<div class="doc_subsubsection">
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]4743 <a name="i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4744</div>
4745<div class="doc_text">
4746
4747<h5>Syntax:</h5>
4748<pre>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]4749 &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]4750</pre>
4751
4752<h5>Overview:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4753<p>The '<tt>fptosi</tt>' instruction converts
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4754 <a href="#t_floating">floating point</a> <tt>value</tt> to
4755 type <tt>ty2</tt>.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]4756
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]4757<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4758<p>The '<tt>fptosi</tt>' instruction takes a value to cast, which must be a
4759 scalar or vector <a href="#t_floating">floating point</a> value, and a type
4760 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
4761 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
4762 vector integer type with the same number of elements as <tt>ty</tt></p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]4763
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]4764<h5>Semantics:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4765<p>The '<tt>fptosi</tt>' instruction converts its
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4766 <a href="#t_floating">floating point</a> operand into the nearest (rounding
4767 towards zero) signed integer value. If the value cannot fit in <tt>ty2</tt>,
4768 the results are undefined.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]4769
Chris Lattner70de6632001-07-09 00:26:23 +0000[diff] [blame]4770<h5>Example:</h5>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]4771<pre>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]4772 %X = fptosi double -123.0 to i32 <i>; yields i32:-123</i>
Chris Lattner5b95a172007-09-22 03:17:52 +0000[diff] [blame]4773 %Y = fptosi float 1.0E-247 to i1 <i>; yields undefined:1</i>
Gabor Greiff50fd572009-10-28 09:21:30 +0000[diff] [blame]4774 %Z = fptosi float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4775</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4776
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4777</div>
4778
4779<!-- _______________________________________________________________________ -->
4780<div class="doc_subsubsection">
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]4781 <a name="i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4782</div>
4783<div class="doc_text">
4784
4785<h5>Syntax:</h5>
4786<pre>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]4787 &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]4788</pre>
4789
4790<h5>Overview:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]4791<p>The '<tt>uitofp</tt>' instruction regards <tt>value</tt> as an unsigned
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4792 integer and converts that value to the <tt>ty2</tt> type.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4793
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4794<h5>Arguments:</h5>
Nate Begemand4d45c22007-11-17 03:58:34 +0000[diff] [blame]4795<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]4796 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
4797 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
4798 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
4799 floating point type with the same number of elements as <tt>ty</tt></p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4800
4801<h5>Semantics:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]4802<p>The '<tt>uitofp</tt>' instruction interprets its operand as an unsigned
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4803 integer quantity and converts it to the corresponding floating point
4804 value. If the value cannot fit in the floating point value, the results are
4805 undefined.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4806
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4807<h5>Example:</h5>
4808<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4809 %X = uitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]4810 %Y = uitofp i8 -1 to double <i>; yields double:255.0</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4811</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4812
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4813</div>
4814
4815<!-- _______________________________________________________________________ -->
4816<div class="doc_subsubsection">
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]4817 <a name="i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4818</div>
4819<div class="doc_text">
4820
4821<h5>Syntax:</h5>
4822<pre>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]4823 &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]4824</pre>
4825
4826<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4827<p>The '<tt>sitofp</tt>' instruction regards <tt>value</tt> as a signed integer
4828 and converts that value to the <tt>ty2</tt> type.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4829
4830<h5>Arguments:</h5>
Nate Begemand4d45c22007-11-17 03:58:34 +0000[diff] [blame]4831<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]4832 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
4833 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
4834 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
4835 floating point type with the same number of elements as <tt>ty</tt></p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4836
4837<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4838<p>The '<tt>sitofp</tt>' instruction interprets its operand as a signed integer
4839 quantity and converts it to the corresponding floating point value. If the
4840 value cannot fit in the floating point value, the results are undefined.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4841
4842<h5>Example:</h5>
4843<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4844 %X = sitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]4845 %Y = sitofp i8 -1 to double <i>; yields double:-1.0</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4846</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4847
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4848</div>
4849
4850<!-- _______________________________________________________________________ -->
4851<div class="doc_subsubsection">
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]4852 <a name="i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a>
4853</div>
4854<div class="doc_text">
4855
4856<h5>Syntax:</h5>
4857<pre>
4858 &lt;result&gt; = ptrtoint &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4859</pre>
4860
4861<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4862<p>The '<tt>ptrtoint</tt>' instruction converts the pointer <tt>value</tt> to
4863 the integer type <tt>ty2</tt>.</p>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]4864
4865<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4866<p>The '<tt>ptrtoint</tt>' instruction takes a <tt>value</tt> to cast, which
4867 must be a <a href="#t_pointer">pointer</a> value, and a type to cast it to
4868 <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]4869
4870<h5>Semantics:</h5>
4871<p>The '<tt>ptrtoint</tt>' instruction converts <tt>value</tt> to integer type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4872 <tt>ty2</tt> by interpreting the pointer value as an integer and either
4873 truncating or zero extending that value to the size of the integer type. If
4874 <tt>value</tt> is smaller than <tt>ty2</tt> then a zero extension is done. If
4875 <tt>value</tt> is larger than <tt>ty2</tt> then a truncation is done. If they
4876 are the same size, then nothing is done (<i>no-op cast</i>) other than a type
4877 change.</p>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]4878
4879<h5>Example:</h5>
4880<pre>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]4881 %X = ptrtoint i32* %X to i8 <i>; yields truncation on 32-bit architecture</i>
4882 %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]4883</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4884
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]4885</div>
4886
4887<!-- _______________________________________________________________________ -->
4888<div class="doc_subsubsection">
4889 <a name="i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a>
4890</div>
4891<div class="doc_text">
4892
4893<h5>Syntax:</h5>
4894<pre>
4895 &lt;result&gt; = inttoptr &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4896</pre>
4897
4898<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4899<p>The '<tt>inttoptr</tt>' instruction converts an integer <tt>value</tt> to a
4900 pointer type, <tt>ty2</tt>.</p>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]4901
4902<h5>Arguments:</h5>
Duncan Sands16f122e2007-03-30 12:22:09 +0000[diff] [blame]4903<p>The '<tt>inttoptr</tt>' instruction takes an <a href="#t_integer">integer</a>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4904 value to cast, and a type to cast it to, which must be a
4905 <a href="#t_pointer">pointer</a> type.</p>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]4906
4907<h5>Semantics:</h5>
4908<p>The '<tt>inttoptr</tt>' instruction converts <tt>value</tt> to type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4909 <tt>ty2</tt> by applying either a zero extension or a truncation depending on
4910 the size of the integer <tt>value</tt>. If <tt>value</tt> is larger than the
4911 size of a pointer then a truncation is done. If <tt>value</tt> is smaller
4912 than the size of a pointer then a zero extension is done. If they are the
4913 same size, nothing is done (<i>no-op cast</i>).</p>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]4914
4915<h5>Example:</h5>
4916<pre>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]4917 %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]4918 %Y = inttoptr i32 255 to i32* <i>; yields no-op on 32-bit architecture</i>
4919 %Z = inttoptr i64 0 to i32* <i>; yields truncation on 32-bit architecture</i>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]4920</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4921
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]4922</div>
4923
4924<!-- _______________________________________________________________________ -->
4925<div class="doc_subsubsection">
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]4926 <a name="i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4927</div>
4928<div class="doc_text">
4929
4930<h5>Syntax:</h5>
4931<pre>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]4932 &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]4933</pre>
4934
4935<h5>Overview:</h5>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]4936<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4937 <tt>ty2</tt> without changing any bits.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4938
4939<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4940<p>The '<tt>bitcast</tt>' instruction takes a value to cast, which must be a
4941 non-aggregate first class value, and a type to cast it to, which must also be
4942 a non-aggregate <a href="#t_firstclass">first class</a> type. The bit sizes
4943 of <tt>value</tt> and the destination type, <tt>ty2</tt>, must be
4944 identical. If the source type is a pointer, the destination type must also be
4945 a pointer. This instruction supports bitwise conversion of vectors to
4946 integers and to vectors of other types (as long as they have the same
4947 size).</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4948
4949<h5>Semantics:</h5>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]4950<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4951 <tt>ty2</tt>. It is always a <i>no-op cast</i> because no bits change with
4952 this conversion. The conversion is done as if the <tt>value</tt> had been
4953 stored to memory and read back as type <tt>ty2</tt>. Pointer types may only
4954 be converted to other pointer types with this instruction. To convert
4955 pointers to other types, use the <a href="#i_inttoptr">inttoptr</a> or
4956 <a href="#i_ptrtoint">ptrtoint</a> instructions first.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4957
4958<h5>Example:</h5>
4959<pre>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]4960 %X = bitcast i8 255 to i8 <i>; yields i8 :-1</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4961 %Y = bitcast i32* %x to sint* <i>; yields sint*:%x</i>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4962 %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]4963</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4964
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4965</div>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]4966
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]4967<!-- ======================================================================= -->
4968<div class="doc_subsection"> <a name="otherops">Other Operations</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4969
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]4970<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4971
4972<p>The instructions in this category are the "miscellaneous" instructions, which
4973 defy better classification.</p>
4974
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]4975</div>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4976
4977<!-- _______________________________________________________________________ -->
4978<div class="doc_subsubsection"><a name="i_icmp">'<tt>icmp</tt>' Instruction</a>
4979</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4980
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4981<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4982
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4983<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4984<pre>
4985 &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]4986</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4987
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4988<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4989<p>The '<tt>icmp</tt>' instruction returns a boolean value or a vector of
4990 boolean values based on comparison of its two integer, integer vector, or
4991 pointer operands.</p>
4992
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4993<h5>Arguments:</h5>
4994<p>The '<tt>icmp</tt>' instruction takes three operands. The first operand is
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4995 the condition code indicating the kind of comparison to perform. It is not a
4996 value, just a keyword. The possible condition code are:</p>
4997
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4998<ol>
4999 <li><tt>eq</tt>: equal</li>
5000 <li><tt>ne</tt>: not equal </li>
5001 <li><tt>ugt</tt>: unsigned greater than</li>
5002 <li><tt>uge</tt>: unsigned greater or equal</li>
5003 <li><tt>ult</tt>: unsigned less than</li>
5004 <li><tt>ule</tt>: unsigned less or equal</li>
5005 <li><tt>sgt</tt>: signed greater than</li>
5006 <li><tt>sge</tt>: signed greater or equal</li>
5007 <li><tt>slt</tt>: signed less than</li>
5008 <li><tt>sle</tt>: signed less or equal</li>
5009</ol>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5010
Chris Lattnerc0f423a2007-01-15 01:54:13 +0000[diff] [blame]5011<p>The remaining two arguments must be <a href="#t_integer">integer</a> or
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5012 <a href="#t_pointer">pointer</a> or integer <a href="#t_vector">vector</a>
5013 typed. They must also be identical types.</p>
5014
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5015<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5016<p>The '<tt>icmp</tt>' compares <tt>op1</tt> and <tt>op2</tt> according to the
5017 condition code given as <tt>cond</tt>. The comparison performed always yields
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]5018 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]5019 result, as follows:</p>
5020
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5021<ol>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5022 <li><tt>eq</tt>: yields <tt>true</tt> if the operands are equal,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5023 <tt>false</tt> otherwise. No sign interpretation is necessary or
5024 performed.</li>
5025
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5026 <li><tt>ne</tt>: yields <tt>true</tt> if the operands are unequal,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5027 <tt>false</tt> otherwise. No sign interpretation is necessary or
5028 performed.</li>
5029
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5030 <li><tt>ugt</tt>: interprets the operands as unsigned values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5031 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
5032
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5033 <li><tt>uge</tt>: interprets the operands as unsigned values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5034 <tt>true</tt> if <tt>op1</tt> is greater than or equal
5035 to <tt>op2</tt>.</li>
5036
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5037 <li><tt>ult</tt>: interprets the operands as unsigned values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5038 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
5039
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5040 <li><tt>ule</tt>: interprets the operands as unsigned values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5041 <tt>true</tt> if <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
5042
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5043 <li><tt>sgt</tt>: interprets the operands as signed values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5044 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
5045
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5046 <li><tt>sge</tt>: interprets the operands as signed values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5047 <tt>true</tt> if <tt>op1</tt> is greater than or equal
5048 to <tt>op2</tt>.</li>
5049
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5050 <li><tt>slt</tt>: interprets the operands as signed values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5051 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
5052
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5053 <li><tt>sle</tt>: interprets the operands as signed values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5054 <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]5055</ol>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5056
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5057<p>If the operands are <a href="#t_pointer">pointer</a> typed, the pointer
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5058 values are compared as if they were integers.</p>
5059
5060<p>If the operands are integer vectors, then they are compared element by
5061 element. The result is an <tt>i1</tt> vector with the same number of elements
5062 as the values being compared. Otherwise, the result is an <tt>i1</tt>.</p>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5063
5064<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5065<pre>
5066 &lt;result&gt; = icmp eq i32 4, 5 <i>; yields: result=false</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]5067 &lt;result&gt; = icmp ne float* %X, %X <i>; yields: result=false</i>
5068 &lt;result&gt; = icmp ult i16 4, 5 <i>; yields: result=true</i>
5069 &lt;result&gt; = icmp sgt i16 4, 5 <i>; yields: result=false</i>
5070 &lt;result&gt; = icmp ule i16 -4, 5 <i>; yields: result=false</i>
5071 &lt;result&gt; = icmp sge i16 4, 5 <i>; yields: result=false</i>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5072</pre>
Dan Gohmana5127ab2009-01-22 01:39:38 +0000[diff] [blame]5073
5074<p>Note that the code generator does not yet support vector types with
5075 the <tt>icmp</tt> instruction.</p>
5076
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5077</div>
5078
5079<!-- _______________________________________________________________________ -->
5080<div class="doc_subsubsection"><a name="i_fcmp">'<tt>fcmp</tt>' Instruction</a>
5081</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5082
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5083<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5084
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5085<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5086<pre>
5087 &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]5088</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5089
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5090<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5091<p>The '<tt>fcmp</tt>' instruction returns a boolean value or vector of boolean
5092 values based on comparison of its operands.</p>
5093
5094<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]5095(<a href="#t_integer"><tt>i1</tt></a>).</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5096
5097<p>If the operands are floating point vectors, then the result type is a vector
5098 of boolean with the same number of elements as the operands being
5099 compared.</p>
5100
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5101<h5>Arguments:</h5>
5102<p>The '<tt>fcmp</tt>' instruction takes three operands. The first operand is
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5103 the condition code indicating the kind of comparison to perform. It is not a
5104 value, just a keyword. The possible condition code are:</p>
5105
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5106<ol>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]5107 <li><tt>false</tt>: no comparison, always returns false</li>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5108 <li><tt>oeq</tt>: ordered and equal</li>
5109 <li><tt>ogt</tt>: ordered and greater than </li>
5110 <li><tt>oge</tt>: ordered and greater than or equal</li>
5111 <li><tt>olt</tt>: ordered and less than </li>
5112 <li><tt>ole</tt>: ordered and less than or equal</li>
5113 <li><tt>one</tt>: ordered and not equal</li>
5114 <li><tt>ord</tt>: ordered (no nans)</li>
5115 <li><tt>ueq</tt>: unordered or equal</li>
5116 <li><tt>ugt</tt>: unordered or greater than </li>
5117 <li><tt>uge</tt>: unordered or greater than or equal</li>
5118 <li><tt>ult</tt>: unordered or less than </li>
5119 <li><tt>ule</tt>: unordered or less than or equal</li>
5120 <li><tt>une</tt>: unordered or not equal</li>
5121 <li><tt>uno</tt>: unordered (either nans)</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]5122 <li><tt>true</tt>: no comparison, always returns true</li>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5123</ol>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5124
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5125<p><i>Ordered</i> means that neither operand is a QNAN while
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5126 <i>unordered</i> means that either operand may be a QNAN.</p>
5127
5128<p>Each of <tt>val1</tt> and <tt>val2</tt> arguments must be either
5129 a <a href="#t_floating">floating point</a> type or
5130 a <a href="#t_vector">vector</a> of floating point type. They must have
5131 identical types.</p>
5132
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5133<h5>Semantics:</h5>
Gabor Greif0f75ad02008-08-07 21:46:00 +0000[diff] [blame]5134<p>The '<tt>fcmp</tt>' instruction compares <tt>op1</tt> and <tt>op2</tt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5135 according to the condition code given as <tt>cond</tt>. If the operands are
5136 vectors, then the vectors are compared element by element. Each comparison
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]5137 performed always yields an <a href="#t_integer">i1</a> result, as
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5138 follows:</p>
5139
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5140<ol>
5141 <li><tt>false</tt>: always yields <tt>false</tt>, regardless of operands.</li>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5142
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5143 <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]5144 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
5145
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]5146 <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]5147 <tt>op1</tt> is greater than <tt>op2</tt>.</li>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5148
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5149 <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]5150 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
5151
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5152 <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]5153 <tt>op1</tt> is less than <tt>op2</tt>.</li>
5154
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5155 <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]5156 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
5157
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5158 <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]5159 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
5160
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]5161 <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]5162
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5163 <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]5164 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
5165
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5166 <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]5167 <tt>op1</tt> is greater than <tt>op2</tt>.</li>
5168
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5169 <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]5170 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
5171
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5172 <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]5173 <tt>op1</tt> is less than <tt>op2</tt>.</li>
5174
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5175 <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]5176 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
5177
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5178 <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]5179 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
5180
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]5181 <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]5182
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5183 <li><tt>true</tt>: always yields <tt>true</tt>, regardless of operands.</li>
5184</ol>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5185
5186<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5187<pre>
5188 &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]5189 &lt;result&gt; = fcmp one float 4.0, 5.0 <i>; yields: result=true</i>
5190 &lt;result&gt; = fcmp olt float 4.0, 5.0 <i>; yields: result=true</i>
5191 &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]5192</pre>
Dan Gohmana5127ab2009-01-22 01:39:38 +0000[diff] [blame]5193
5194<p>Note that the code generator does not yet support vector types with
5195 the <tt>fcmp</tt> instruction.</p>
5196
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5197</div>
5198
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5199<!-- _______________________________________________________________________ -->
Nate Begemand2195702008-05-12 19:01:56 +0000[diff] [blame]5200<div class="doc_subsubsection">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]5201 <a name="i_phi">'<tt>phi</tt>' Instruction</a>
5202</div>
5203
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5204<div class="doc_text">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]5205
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5206<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5207<pre>
5208 &lt;result&gt; = phi &lt;ty&gt; [ &lt;val0&gt;, &lt;label0&gt;], ...
5209</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]5210
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5211<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5212<p>The '<tt>phi</tt>' instruction is used to implement the &#966; node in the
5213 SSA graph representing the function.</p>
5214
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5215<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5216<p>The type of the incoming values is specified with the first type field. After
5217 this, the '<tt>phi</tt>' instruction takes a list of pairs as arguments, with
5218 one pair for each predecessor basic block of the current block. Only values
5219 of <a href="#t_firstclass">first class</a> type may be used as the value
5220 arguments to the PHI node. Only labels may be used as the label
5221 arguments.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]5222
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5223<p>There must be no non-phi instructions between the start of a basic block and
5224 the PHI instructions: i.e. PHI instructions must be first in a basic
5225 block.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]5226
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5227<p>For the purposes of the SSA form, the use of each incoming value is deemed to
5228 occur on the edge from the corresponding predecessor block to the current
5229 block (but after any definition of an '<tt>invoke</tt>' instruction's return
5230 value on the same edge).</p>
Jay Foad1a4eea52009-06-03 10:20:10 +0000[diff] [blame]5231
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5232<h5>Semantics:</h5>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5233<p>At runtime, the '<tt>phi</tt>' instruction logically takes on the value
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5234 specified by the pair corresponding to the predecessor basic block that
5235 executed just prior to the current block.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]5236
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5237<h5>Example:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]5238<pre>
5239Loop: ; Infinite loop that counts from 0 on up...
5240 %indvar = phi i32 [ 0, %LoopHeader ], [ %nextindvar, %Loop ]
5241 %nextindvar = add i32 %indvar, 1
5242 br label %Loop
5243</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5244
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5245</div>
5246
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5247<!-- _______________________________________________________________________ -->
5248<div class="doc_subsubsection">
5249 <a name="i_select">'<tt>select</tt>' Instruction</a>
5250</div>
5251
5252<div class="doc_text">
5253
5254<h5>Syntax:</h5>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5255<pre>
Dan Gohmanc579d972008-09-09 01:02:47 +0000[diff] [blame]5256 &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>
5257
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]5258 <i>selty</i> is either i1 or {&lt;N x i1&gt;}
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5259</pre>
5260
5261<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5262<p>The '<tt>select</tt>' instruction is used to choose one value based on a
5263 condition, without branching.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5264
5265
5266<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5267<p>The '<tt>select</tt>' instruction requires an 'i1' value or a vector of 'i1'
5268 values indicating the condition, and two values of the
5269 same <a href="#t_firstclass">first class</a> type. If the val1/val2 are
5270 vectors and the condition is a scalar, then entire vectors are selected, not
5271 individual elements.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5272
5273<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5274<p>If the condition is an i1 and it evaluates to 1, the instruction returns the
5275 first value argument; otherwise, it returns the second value argument.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5276
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5277<p>If the condition is a vector of i1, then the value arguments must be vectors
5278 of the same size, and the selection is done element by element.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5279
5280<h5>Example:</h5>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5281<pre>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]5282 %X = select i1 true, i8 17, i8 42 <i>; yields i8:17</i>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5283</pre>
Dan Gohmana5127ab2009-01-22 01:39:38 +0000[diff] [blame]5284
5285<p>Note that the code generator does not yet support conditions
5286 with vector type.</p>
5287
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5288</div>
5289
Robert Bocchinof72fdfe2006-01-15 20:48:27 +0000[diff] [blame]5290<!-- _______________________________________________________________________ -->
5291<div class="doc_subsubsection">
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5292 <a name="i_call">'<tt>call</tt>' Instruction</a>
5293</div>
5294
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5295<div class="doc_text">
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5296
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]5297<h5>Syntax:</h5>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5298<pre>
Devang Patel02256232008-10-07 17:48:33 +0000[diff] [blame]5299 &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]5300</pre>
5301
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]5302<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5303<p>The '<tt>call</tt>' instruction represents a simple function call.</p>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5304
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]5305<h5>Arguments:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5306<p>This instruction requires several arguments:</p>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5307
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]5308<ol>
Jeffrey Yasskinb8677462010-01-09 19:44:16 +0000[diff] [blame]5309 <li>The optional "tail" marker indicates that the callee function does not
5310 access any allocas or varargs in the caller. Note that calls may be
5311 marked "tail" even if they do not occur before
5312 a <a href="#i_ret"><tt>ret</tt></a> instruction. If the "tail" marker is
5313 present, the function call is eligible for tail call optimization,
5314 but <a href="CodeGenerator.html#tailcallopt">might not in fact be
Evan Cheng59676492010-03-08 21:05:02 +0000[diff] [blame]5315 optimized into a jump</a>. The code generator may optimize calls marked
5316 "tail" with either 1) automatic <a href="CodeGenerator.html#sibcallopt">
5317 sibling call optimization</a> when the caller and callee have
5318 matching signatures, or 2) forced tail call optimization when the
5319 following extra requirements are met:
Jeffrey Yasskinb8677462010-01-09 19:44:16 +0000[diff] [blame]5320 <ul>
5321 <li>Caller and callee both have the calling
5322 convention <tt>fastcc</tt>.</li>
5323 <li>The call is in tail position (ret immediately follows call and ret
5324 uses value of call or is void).</li>
5325 <li>Option <tt>-tailcallopt</tt> is enabled,
Dan Gohman6232f732010-03-02 01:08:11 +0000[diff] [blame]5326 or <code>llvm::GuaranteedTailCallOpt</code> is <code>true</code>.</li>
Jeffrey Yasskinb8677462010-01-09 19:44:16 +0000[diff] [blame]5327 <li><a href="CodeGenerator.html#tailcallopt">Platform specific
5328 constraints are met.</a></li>
5329 </ul>
5330 </li>
Devang Patel7e9b05e2008-10-06 18:50:38 +0000[diff] [blame]5331
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5332 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
5333 convention</a> the call should use. If none is specified, the call
Jeffrey Yasskinb8677462010-01-09 19:44:16 +0000[diff] [blame]5334 defaults to using C calling conventions. The calling convention of the
5335 call must match the calling convention of the target function, or else the
5336 behavior is undefined.</li>
Devang Patel7e9b05e2008-10-06 18:50:38 +0000[diff] [blame]5337
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5338 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
5339 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
5340 '<tt>inreg</tt>' attributes are valid here.</li>
5341
5342 <li>'<tt>ty</tt>': the type of the call instruction itself which is also the
5343 type of the return value. Functions that return no value are marked
5344 <tt><a href="#t_void">void</a></tt>.</li>
5345
5346 <li>'<tt>fnty</tt>': shall be the signature of the pointer to function value
5347 being invoked. The argument types must match the types implied by this
5348 signature. This type can be omitted if the function is not varargs and if
5349 the function type does not return a pointer to a function.</li>
5350
5351 <li>'<tt>fnptrval</tt>': An LLVM value containing a pointer to a function to
5352 be invoked. In most cases, this is a direct function invocation, but
5353 indirect <tt>call</tt>s are just as possible, calling an arbitrary pointer
5354 to function value.</li>
5355
5356 <li>'<tt>function args</tt>': argument list whose types match the function
Chris Lattner47f2a832010-03-02 06:36:51 +0000[diff] [blame]5357 signature argument types and parameter attributes. All arguments must be
5358 of <a href="#t_firstclass">first class</a> type. If the function
5359 signature indicates the function accepts a variable number of arguments,
5360 the extra arguments can be specified.</li>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5361
5362 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
5363 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
5364 '<tt>readnone</tt>' attributes are valid here.</li>
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]5365</ol>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5366
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]5367<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5368<p>The '<tt>call</tt>' instruction is used to cause control flow to transfer to
5369 a specified function, with its incoming arguments bound to the specified
5370 values. Upon a '<tt><a href="#i_ret">ret</a></tt>' instruction in the called
5371 function, control flow continues with the instruction after the function
5372 call, and the return value of the function is bound to the result
5373 argument.</p>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5374
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]5375<h5>Example:</h5>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5376<pre>
Nick Lewyckya9b13d52007-09-08 13:57:50 +0000[diff] [blame]5377 %retval = call i32 @test(i32 %argc)
Chris Lattnerfb7c88d2008-03-21 17:24:17 +0000[diff] [blame]5378 call i32 (i8 *, ...)* @printf(i8 * %msg, i32 12, i8 42) <i>; yields i32</i>
5379 %X = tail call i32 @foo() <i>; yields i32</i>
5380 %Y = tail call <a href="#callingconv">fastcc</a> i32 @foo() <i>; yields i32</i>
5381 call void %foo(i8 97 signext)
Devang Pateld6cff512008-03-10 20:49:15 +0000[diff] [blame]5382
5383 %struct.A = type { i32, i8 }
Devang Patel7e9b05e2008-10-06 18:50:38 +0000[diff] [blame]5384 %r = call %struct.A @foo() <i>; yields { 32, i8 }</i>
Dan Gohmancc3132e2008-10-04 19:00:07 +0000[diff] [blame]5385 %gr = extractvalue %struct.A %r, 0 <i>; yields i32</i>
5386 %gr1 = extractvalue %struct.A %r, 1 <i>; yields i8</i>
Chris Lattner6cbe8e92008-10-08 06:26:11 +0000[diff] [blame]5387 %Z = call void @foo() noreturn <i>; indicates that %foo never returns normally</i>
Matthijs Kooijmaneefa7df2008-10-07 10:03:45 +0000[diff] [blame]5388 %ZZ = call zeroext i32 @bar() <i>; Return value is %zero extended</i>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5389</pre>
5390
Dale Johannesen68f971b2009-09-24 18:38:21 +0000[diff] [blame]5391<p>llvm treats calls to some functions with names and arguments that match the
Dale Johannesen722212d2009-09-25 17:04:42 +0000[diff] [blame]5392standard C99 library as being the C99 library functions, and may perform
5393optimizations or generate code for them under that assumption. This is
5394something we'd like to change in the future to provide better support for
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]5395freestanding environments and non-C-based languages.</p>
Dale Johannesen68f971b2009-09-24 18:38:21 +0000[diff] [blame]5396
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5397</div>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5398
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5399<!-- _______________________________________________________________________ -->
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5400<div class="doc_subsubsection">
Chris Lattner33337472006-01-13 23:26:01 +0000[diff] [blame]5401 <a name="i_va_arg">'<tt>va_arg</tt>' Instruction</a>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5402</div>
5403
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5404<div class="doc_text">
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5405
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]5406<h5>Syntax:</h5>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5407<pre>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]5408 &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]5409</pre>
5410
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]5411<h5>Overview:</h5>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]5412<p>The '<tt>va_arg</tt>' instruction is used to access arguments passed through
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5413 the "variable argument" area of a function call. It is used to implement the
5414 <tt>va_arg</tt> macro in C.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5415
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]5416<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5417<p>This instruction takes a <tt>va_list*</tt> value and the type of the
5418 argument. It returns a value of the specified argument type and increments
5419 the <tt>va_list</tt> to point to the next argument. The actual type
5420 of <tt>va_list</tt> is target specific.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5421
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]5422<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5423<p>The '<tt>va_arg</tt>' instruction loads an argument of the specified type
5424 from the specified <tt>va_list</tt> and causes the <tt>va_list</tt> to point
5425 to the next argument. For more information, see the variable argument
5426 handling <a href="#int_varargs">Intrinsic Functions</a>.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5427
5428<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]5429 take a variable number of arguments, for example, the <tt>vfprintf</tt>
5430 function.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5431
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5432<p><tt>va_arg</tt> is an LLVM instruction instead of
5433 an <a href="#intrinsics">intrinsic function</a> because it takes a type as an
5434 argument.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5435
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]5436<h5>Example:</h5>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5437<p>See the <a href="#int_varargs">variable argument processing</a> section.</p>
5438
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5439<p>Note that the code generator does not yet fully support va_arg on many
5440 targets. Also, it does not currently support va_arg with aggregate types on
5441 any target.</p>
Dan Gohman3065b612009-01-12 23:12:39 +0000[diff] [blame]5442
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5443</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5444
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5445<!-- *********************************************************************** -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]5446<div class="doc_section"> <a name="intrinsics">Intrinsic Functions</a> </div>
5447<!-- *********************************************************************** -->
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5448
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5449<div class="doc_text">
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5450
5451<p>LLVM supports the notion of an "intrinsic function". These functions have
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5452 well known names and semantics and are required to follow certain
5453 restrictions. Overall, these intrinsics represent an extension mechanism for
5454 the LLVM language that does not require changing all of the transformations
5455 in LLVM when adding to the language (or the bitcode reader/writer, the
5456 parser, etc...).</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5457
John Criswell88190562005-05-16 16:17:45 +0000[diff] [blame]5458<p>Intrinsic function names must all start with an "<tt>llvm.</tt>" prefix. This
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5459 prefix is reserved in LLVM for intrinsic names; thus, function names may not
5460 begin with this prefix. Intrinsic functions must always be external
5461 functions: you cannot define the body of intrinsic functions. Intrinsic
5462 functions may only be used in call or invoke instructions: it is illegal to
5463 take the address of an intrinsic function. Additionally, because intrinsic
5464 functions are part of the LLVM language, it is required if any are added that
5465 they be documented here.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5466
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5467<p>Some intrinsic functions can be overloaded, i.e., the intrinsic represents a
5468 family of functions that perform the same operation but on different data
5469 types. Because LLVM can represent over 8 million different integer types,
5470 overloading is used commonly to allow an intrinsic function to operate on any
5471 integer type. One or more of the argument types or the result type can be
5472 overloaded to accept any integer type. Argument types may also be defined as
5473 exactly matching a previous argument's type or the result type. This allows
5474 an intrinsic function which accepts multiple arguments, but needs all of them
5475 to be of the same type, to only be overloaded with respect to a single
5476 argument or the result.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5477
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5478<p>Overloaded intrinsics will have the names of its overloaded argument types
5479 encoded into its function name, each preceded by a period. Only those types
5480 which are overloaded result in a name suffix. Arguments whose type is matched
5481 against another type do not. For example, the <tt>llvm.ctpop</tt> function
5482 can take an integer of any width and returns an integer of exactly the same
5483 integer width. This leads to a family of functions such as
5484 <tt>i8 @llvm.ctpop.i8(i8 %val)</tt> and <tt>i29 @llvm.ctpop.i29(i29
5485 %val)</tt>. Only one type, the return type, is overloaded, and only one type
5486 suffix is required. Because the argument's type is matched against the return
5487 type, it does not require its own name suffix.</p>
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]5488
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5489<p>To learn how to add an intrinsic function, please see the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5490 <a href="ExtendingLLVM.html">Extending LLVM Guide</a>.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5491
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5492</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5493
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5494<!-- ======================================================================= -->
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5495<div class="doc_subsection">
5496 <a name="int_varargs">Variable Argument Handling Intrinsics</a>
5497</div>
5498
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5499<div class="doc_text">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5500
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5501<p>Variable argument support is defined in LLVM with
5502 the <a href="#i_va_arg"><tt>va_arg</tt></a> instruction and these three
5503 intrinsic functions. These functions are related to the similarly named
5504 macros defined in the <tt>&lt;stdarg.h&gt;</tt> header file.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5505
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5506<p>All of these functions operate on arguments that use a target-specific value
5507 type "<tt>va_list</tt>". The LLVM assembly language reference manual does
5508 not define what this type is, so all transformations should be prepared to
5509 handle these functions regardless of the type used.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5510
Chris Lattner30b868d2006-05-15 17:26:46 +0000[diff] [blame]5511<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]5512 instruction and the variable argument handling intrinsic functions are
5513 used.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5514
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]5515<div class="doc_code">
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5516<pre>
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]5517define i32 @test(i32 %X, ...) {
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5518 ; Initialize variable argument processing
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5519 %ap = alloca i8*
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]5520 %ap2 = bitcast i8** %ap to i8*
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]5521 call void @llvm.va_start(i8* %ap2)
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5522
5523 ; Read a single integer argument
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5524 %tmp = va_arg i8** %ap, i32
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5525
5526 ; Demonstrate usage of llvm.va_copy and llvm.va_end
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5527 %aq = alloca i8*
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]5528 %aq2 = bitcast i8** %aq to i8*
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5529 call void @llvm.va_copy(i8* %aq2, i8* %ap2)
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]5530 call void @llvm.va_end(i8* %aq2)
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5531
5532 ; Stop processing of arguments.
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]5533 call void @llvm.va_end(i8* %ap2)
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]5534 ret i32 %tmp
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5535}
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]5536
5537declare void @llvm.va_start(i8*)
5538declare void @llvm.va_copy(i8*, i8*)
5539declare void @llvm.va_end(i8*)
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5540</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5541</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5542
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]5543</div>
5544
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5545<!-- _______________________________________________________________________ -->
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5546<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5547 <a name="int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5548</div>
5549
5550
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5551<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5552
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5553<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5554<pre>
5555 declare void %llvm.va_start(i8* &lt;arglist&gt;)
5556</pre>
5557
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5558<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5559<p>The '<tt>llvm.va_start</tt>' intrinsic initializes <tt>*&lt;arglist&gt;</tt>
5560 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]5561
5562<h5>Arguments:</h5>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]5563<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]5564
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5565<h5>Semantics:</h5>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]5566<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]5567 macro available in C. In a target-dependent way, it initializes
5568 the <tt>va_list</tt> element to which the argument points, so that the next
5569 call to <tt>va_arg</tt> will produce the first variable argument passed to
5570 the function. Unlike the C <tt>va_start</tt> macro, this intrinsic does not
5571 need to know the last argument of the function as the compiler can figure
5572 that out.</p>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]5573
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5574</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5575
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5576<!-- _______________________________________________________________________ -->
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5577<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5578 <a name="int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5579</div>
5580
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5581<div class="doc_text">
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]5582
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5583<h5>Syntax:</h5>
5584<pre>
5585 declare void @llvm.va_end(i8* &lt;arglist&gt;)
5586</pre>
5587
5588<h5>Overview:</h5>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5589<p>The '<tt>llvm.va_end</tt>' intrinsic destroys <tt>*&lt;arglist&gt;</tt>,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5590 which has been initialized previously
5591 with <tt><a href="#int_va_start">llvm.va_start</a></tt>
5592 or <tt><a href="#i_va_copy">llvm.va_copy</a></tt>.</p>
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]5593
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5594<h5>Arguments:</h5>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5595<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]5596
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5597<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5598<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]5599 macro available in C. In a target-dependent way, it destroys
5600 the <tt>va_list</tt> element to which the argument points. Calls
5601 to <a href="#int_va_start"><tt>llvm.va_start</tt></a>
5602 and <a href="#int_va_copy"> <tt>llvm.va_copy</tt></a> must be matched exactly
5603 with calls to <tt>llvm.va_end</tt>.</p>
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]5604
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5605</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5606
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5607<!-- _______________________________________________________________________ -->
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5608<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5609 <a name="int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5610</div>
5611
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5612<div class="doc_text">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5613
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5614<h5>Syntax:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5615<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]5616 declare void @llvm.va_copy(i8* &lt;destarglist&gt;, i8* &lt;srcarglist&gt;)
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5617</pre>
5618
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5619<h5>Overview:</h5>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5620<p>The '<tt>llvm.va_copy</tt>' intrinsic copies the current argument position
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5621 from the source argument list to the destination argument list.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5622
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5623<h5>Arguments:</h5>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]5624<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]5625 The second argument is a pointer to a <tt>va_list</tt> element to copy
5626 from.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5627
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5628<h5>Semantics:</h5>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5629<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]5630 macro available in C. In a target-dependent way, it copies the
5631 source <tt>va_list</tt> element into the destination <tt>va_list</tt>
5632 element. This intrinsic is necessary because
5633 the <tt><a href="#int_va_start"> llvm.va_start</a></tt> intrinsic may be
5634 arbitrarily complex and require, for example, memory allocation.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5635
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5636</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5637
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5638<!-- ======================================================================= -->
5639<div class="doc_subsection">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5640 <a name="int_gc">Accurate Garbage Collection Intrinsics</a>
5641</div>
5642
5643<div class="doc_text">
5644
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5645<p>LLVM support for <a href="GarbageCollection.html">Accurate Garbage
Chris Lattner67c37d12008-08-05 18:29:16 +0000[diff] [blame]5646Collection</a> (GC) requires the implementation and generation of these
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5647intrinsics. These intrinsics allow identification of <a href="#int_gcroot">GC
5648roots on the stack</a>, as well as garbage collector implementations that
5649require <a href="#int_gcread">read</a> and <a href="#int_gcwrite">write</a>
5650barriers. Front-ends for type-safe garbage collected languages should generate
5651these intrinsics to make use of the LLVM garbage collectors. For more details,
5652see <a href="GarbageCollection.html">Accurate Garbage Collection with
5653LLVM</a>.</p>
Christopher Lamb55c6d4f2007-12-17 01:00:21 +0000[diff] [blame]5654
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5655<p>The garbage collection intrinsics only operate on objects in the generic
5656 address space (address space zero).</p>
Christopher Lamb55c6d4f2007-12-17 01:00:21 +0000[diff] [blame]5657
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5658</div>
5659
5660<!-- _______________________________________________________________________ -->
5661<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5662 <a name="int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5663</div>
5664
5665<div class="doc_text">
5666
5667<h5>Syntax:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5668<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]5669 declare void @llvm.gcroot(i8** %ptrloc, i8* %metadata)
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5670</pre>
5671
5672<h5>Overview:</h5>
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]5673<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]5674 the code generator, and allows some metadata to be associated with it.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5675
5676<h5>Arguments:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5677<p>The first argument specifies the address of a stack object that contains the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5678 root pointer. The second pointer (which must be either a constant or a
5679 global value address) contains the meta-data to be associated with the
5680 root.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5681
5682<h5>Semantics:</h5>
Chris Lattner851b7712008-04-24 05:59:56 +0000[diff] [blame]5683<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]5684 location. At compile-time, the code generator generates information to allow
5685 the runtime to find the pointer at GC safe points. The '<tt>llvm.gcroot</tt>'
5686 intrinsic may only be used in a function which <a href="#gc">specifies a GC
5687 algorithm</a>.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5688
5689</div>
5690
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5691<!-- _______________________________________________________________________ -->
5692<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5693 <a name="int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5694</div>
5695
5696<div class="doc_text">
5697
5698<h5>Syntax:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5699<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]5700 declare i8* @llvm.gcread(i8* %ObjPtr, i8** %Ptr)
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5701</pre>
5702
5703<h5>Overview:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5704<p>The '<tt>llvm.gcread</tt>' intrinsic identifies reads of references from heap
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5705 locations, allowing garbage collector implementations that require read
5706 barriers.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5707
5708<h5>Arguments:</h5>
Chris Lattnerf9228072006-03-14 20:02:51 +0000[diff] [blame]5709<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]5710 allocated from the garbage collector. The first object is a pointer to the
5711 start of the referenced object, if needed by the language runtime (otherwise
5712 null).</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5713
5714<h5>Semantics:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5715<p>The '<tt>llvm.gcread</tt>' intrinsic has the same semantics as a load
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5716 instruction, but may be replaced with substantially more complex code by the
5717 garbage collector runtime, as needed. The '<tt>llvm.gcread</tt>' intrinsic
5718 may only be used in a function which <a href="#gc">specifies a GC
5719 algorithm</a>.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5720
5721</div>
5722
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5723<!-- _______________________________________________________________________ -->
5724<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5725 <a name="int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5726</div>
5727
5728<div class="doc_text">
5729
5730<h5>Syntax:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5731<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]5732 declare void @llvm.gcwrite(i8* %P1, i8* %Obj, i8** %P2)
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5733</pre>
5734
5735<h5>Overview:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5736<p>The '<tt>llvm.gcwrite</tt>' intrinsic identifies writes of references to heap
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5737 locations, allowing garbage collector implementations that require write
5738 barriers (such as generational or reference counting collectors).</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5739
5740<h5>Arguments:</h5>
Chris Lattnerf9228072006-03-14 20:02:51 +0000[diff] [blame]5741<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]5742 object to store it to, and the third is the address of the field of Obj to
5743 store to. If the runtime does not require a pointer to the object, Obj may
5744 be null.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5745
5746<h5>Semantics:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5747<p>The '<tt>llvm.gcwrite</tt>' intrinsic has the same semantics as a store
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5748 instruction, but may be replaced with substantially more complex code by the
5749 garbage collector runtime, as needed. The '<tt>llvm.gcwrite</tt>' intrinsic
5750 may only be used in a function which <a href="#gc">specifies a GC
5751 algorithm</a>.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5752
5753</div>
5754
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5755<!-- ======================================================================= -->
5756<div class="doc_subsection">
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5757 <a name="int_codegen">Code Generator Intrinsics</a>
5758</div>
5759
5760<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5761
5762<p>These intrinsics are provided by LLVM to expose special features that may
5763 only be implemented with code generator support.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5764
5765</div>
5766
5767<!-- _______________________________________________________________________ -->
5768<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5769 <a name="int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5770</div>
5771
5772<div class="doc_text">
5773
5774<h5>Syntax:</h5>
5775<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]5776 declare i8 *@llvm.returnaddress(i32 &lt;level&gt;)
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5777</pre>
5778
5779<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5780<p>The '<tt>llvm.returnaddress</tt>' intrinsic attempts to compute a
5781 target-specific value indicating the return address of the current function
5782 or one of its callers.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5783
5784<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5785<p>The argument to this intrinsic indicates which function to return the address
5786 for. Zero indicates the calling function, one indicates its caller, etc.
5787 The argument is <b>required</b> to be a constant integer value.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5788
5789<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5790<p>The '<tt>llvm.returnaddress</tt>' intrinsic either returns a pointer
5791 indicating the return address of the specified call frame, or zero if it
5792 cannot be identified. The value returned by this intrinsic is likely to be
5793 incorrect or 0 for arguments other than zero, so it should only be used for
5794 debugging purposes.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5795
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5796<p>Note that calling this intrinsic does not prevent function inlining or other
5797 aggressive transformations, so the value returned may not be that of the
5798 obvious source-language caller.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5799
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5800</div>
5801
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5802<!-- _______________________________________________________________________ -->
5803<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5804 <a name="int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5805</div>
5806
5807<div class="doc_text">
5808
5809<h5>Syntax:</h5>
5810<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]5811 declare i8 *@llvm.frameaddress(i32 &lt;level&gt;)
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5812</pre>
5813
5814<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5815<p>The '<tt>llvm.frameaddress</tt>' intrinsic attempts to return the
5816 target-specific frame pointer value for the specified stack frame.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5817
5818<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5819<p>The argument to this intrinsic indicates which function to return the frame
5820 pointer for. Zero indicates the calling function, one indicates its caller,
5821 etc. The argument is <b>required</b> to be a constant integer value.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5822
5823<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5824<p>The '<tt>llvm.frameaddress</tt>' intrinsic either returns a pointer
5825 indicating the frame address of the specified call frame, or zero if it
5826 cannot be identified. The value returned by this intrinsic is likely to be
5827 incorrect or 0 for arguments other than zero, so it should only be used for
5828 debugging purposes.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5829
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5830<p>Note that calling this intrinsic does not prevent function inlining or other
5831 aggressive transformations, so the value returned may not be that of the
5832 obvious source-language caller.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5833
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5834</div>
5835
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]5836<!-- _______________________________________________________________________ -->
5837<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5838 <a name="int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]5839</div>
5840
5841<div class="doc_text">
5842
5843<h5>Syntax:</h5>
5844<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]5845 declare i8 *@llvm.stacksave()
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]5846</pre>
5847
5848<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5849<p>The '<tt>llvm.stacksave</tt>' intrinsic is used to remember the current state
5850 of the function stack, for use
5851 with <a href="#int_stackrestore"> <tt>llvm.stackrestore</tt></a>. This is
5852 useful for implementing language features like scoped automatic variable
5853 sized arrays in C99.</p>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]5854
5855<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5856<p>This intrinsic returns a opaque pointer value that can be passed
5857 to <a href="#int_stackrestore"><tt>llvm.stackrestore</tt></a>. When
5858 an <tt>llvm.stackrestore</tt> intrinsic is executed with a value saved
5859 from <tt>llvm.stacksave</tt>, it effectively restores the state of the stack
5860 to the state it was in when the <tt>llvm.stacksave</tt> intrinsic executed.
5861 In practice, this pops any <a href="#i_alloca">alloca</a> blocks from the
5862 stack that were allocated after the <tt>llvm.stacksave</tt> was executed.</p>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]5863
5864</div>
5865
5866<!-- _______________________________________________________________________ -->
5867<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5868 <a name="int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]5869</div>
5870
5871<div class="doc_text">
5872
5873<h5>Syntax:</h5>
5874<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]5875 declare void @llvm.stackrestore(i8 * %ptr)
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]5876</pre>
5877
5878<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5879<p>The '<tt>llvm.stackrestore</tt>' intrinsic is used to restore the state of
5880 the function stack to the state it was in when the
5881 corresponding <a href="#int_stacksave"><tt>llvm.stacksave</tt></a> intrinsic
5882 executed. This is useful for implementing language features like scoped
5883 automatic variable sized arrays in C99.</p>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]5884
5885<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5886<p>See the description
5887 for <a href="#int_stacksave"><tt>llvm.stacksave</tt></a>.</p>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]5888
5889</div>
5890
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]5891<!-- _______________________________________________________________________ -->
5892<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5893 <a name="int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a>
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]5894</div>
5895
5896<div class="doc_text">
5897
5898<h5>Syntax:</h5>
5899<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]5900 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]5901</pre>
5902
5903<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5904<p>The '<tt>llvm.prefetch</tt>' intrinsic is a hint to the code generator to
5905 insert a prefetch instruction if supported; otherwise, it is a noop.
5906 Prefetches have no effect on the behavior of the program but can change its
5907 performance characteristics.</p>
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]5908
5909<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5910<p><tt>address</tt> is the address to be prefetched, <tt>rw</tt> is the
5911 specifier determining if the fetch should be for a read (0) or write (1),
5912 and <tt>locality</tt> is a temporal locality specifier ranging from (0) - no
5913 locality, to (3) - extremely local keep in cache. The <tt>rw</tt>
5914 and <tt>locality</tt> arguments must be constant integers.</p>
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]5915
5916<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5917<p>This intrinsic does not modify the behavior of the program. In particular,
5918 prefetches cannot trap and do not produce a value. On targets that support
5919 this intrinsic, the prefetch can provide hints to the processor cache for
5920 better performance.</p>
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]5921
5922</div>
5923
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]5924<!-- _______________________________________________________________________ -->
5925<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5926 <a name="int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a>
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]5927</div>
5928
5929<div class="doc_text">
5930
5931<h5>Syntax:</h5>
5932<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]5933 declare void @llvm.pcmarker(i32 &lt;id&gt;)
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]5934</pre>
5935
5936<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5937<p>The '<tt>llvm.pcmarker</tt>' intrinsic is a method to export a Program
5938 Counter (PC) in a region of code to simulators and other tools. The method
5939 is target specific, but it is expected that the marker will use exported
5940 symbols to transmit the PC of the marker. The marker makes no guarantees
5941 that it will remain with any specific instruction after optimizations. It is
5942 possible that the presence of a marker will inhibit optimizations. The
5943 intended use is to be inserted after optimizations to allow correlations of
5944 simulation runs.</p>
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]5945
5946<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5947<p><tt>id</tt> is a numerical id identifying the marker.</p>
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]5948
5949<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5950<p>This intrinsic does not modify the behavior of the program. Backends that do
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]5951 not support this intrinsic may ignore it.</p>
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]5952
5953</div>
5954
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]5955<!-- _______________________________________________________________________ -->
5956<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5957 <a name="int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a>
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]5958</div>
5959
5960<div class="doc_text">
5961
5962<h5>Syntax:</h5>
5963<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]5964 declare i64 @llvm.readcyclecounter( )
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]5965</pre>
5966
5967<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5968<p>The '<tt>llvm.readcyclecounter</tt>' intrinsic provides access to the cycle
5969 counter register (or similar low latency, high accuracy clocks) on those
5970 targets that support it. On X86, it should map to RDTSC. On Alpha, it
5971 should map to RPCC. As the backing counters overflow quickly (on the order
5972 of 9 seconds on alpha), this should only be used for small timings.</p>
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]5973
5974<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5975<p>When directly supported, reading the cycle counter should not modify any
5976 memory. Implementations are allowed to either return a application specific
5977 value or a system wide value. On backends without support, this is lowered
5978 to a constant 0.</p>
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]5979
5980</div>
5981
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5982<!-- ======================================================================= -->
5983<div class="doc_subsection">
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5984 <a name="int_libc">Standard C Library Intrinsics</a>
5985</div>
5986
5987<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5988
5989<p>LLVM provides intrinsics for a few important standard C library functions.
5990 These intrinsics allow source-language front-ends to pass information about
5991 the alignment of the pointer arguments to the code generator, providing
5992 opportunity for more efficient code generation.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5993
5994</div>
5995
5996<!-- _______________________________________________________________________ -->
5997<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5998 <a name="int_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5999</div>
6000
6001<div class="doc_text">
6002
6003<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6004<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]6005 integer bit width and for different address spaces. Not all targets support
6006 all bit widths however.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6007
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6008<pre>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6009 declare void @llvm.memcpy.p0i8.p0i8.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
6010 i32 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
6011 declare void @llvm.memcpy.p0i8.p0i8.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
6012 i64 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6013</pre>
6014
6015<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6016<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
6017 source location to the destination location.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6018
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6019<p>Note that, unlike the standard libc function, the <tt>llvm.memcpy.*</tt>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6020 intrinsics do not return a value, takes extra alignment/isvolatile arguments
6021 and the pointers can be in specified address spaces.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6022
6023<h5>Arguments:</h5>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6024
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6025<p>The first argument is a pointer to the destination, the second is a pointer
6026 to the source. The third argument is an integer argument specifying the
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6027 number of bytes to copy, the fourth argument is the alignment of the
6028 source and destination locations, and the fifth is a boolean indicating a
6029 volatile access.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6030
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]6031<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]6032 then the caller guarantees that both the source and destination pointers are
6033 aligned to that boundary.</p>
Chris Lattner4c67c482004-02-12 21:18:15 +0000[diff] [blame]6034
Jeffrey Yasskin5d284ae2010-04-26 21:21:24 +0000[diff] [blame]6035<p>If the <tt>isvolatile</tt> parameter is <tt>true</tt>, the
6036 <tt>llvm.memcpy</tt> call is a <a href="#volatile">volatile operation</a>.
6037 The detailed access behavior is not very cleanly specified and it is unwise
6038 to depend on it.</p>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6039
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6040<h5>Semantics:</h5>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6041
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6042<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
6043 source location to the destination location, which are not allowed to
6044 overlap. It copies "len" bytes of memory over. If the argument is known to
6045 be aligned to some boundary, this can be specified as the fourth argument,
6046 otherwise it should be set to 0 or 1.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6047
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6048</div>
6049
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6050<!-- _______________________________________________________________________ -->
6051<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6052 <a name="int_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a>
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6053</div>
6054
6055<div class="doc_text">
6056
6057<h5>Syntax:</h5>
Chris Lattnerdd708342008-11-21 16:42:48 +0000[diff] [blame]6058<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]6059 width and for different address space. Not all targets support all bit
6060 widths however.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6061
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6062<pre>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6063 declare void @llvm.memmove.p0i8.p0i8.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
6064 i32 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
6065 declare void @llvm.memmove.p0i8.p0i8.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
6066 i64 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6067</pre>
6068
6069<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6070<p>The '<tt>llvm.memmove.*</tt>' intrinsics move a block of memory from the
6071 source location to the destination location. It is similar to the
6072 '<tt>llvm.memcpy</tt>' intrinsic but allows the two memory locations to
6073 overlap.</p>
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6074
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6075<p>Note that, unlike the standard libc function, the <tt>llvm.memmove.*</tt>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6076 intrinsics do not return a value, takes extra alignment/isvolatile arguments
6077 and the pointers can be in specified address spaces.</p>
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6078
6079<h5>Arguments:</h5>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6080
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6081<p>The first argument is a pointer to the destination, the second is a pointer
6082 to the source. The third argument is an integer argument specifying the
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6083 number of bytes to copy, the fourth argument is the alignment of the
6084 source and destination locations, and the fifth is a boolean indicating a
6085 volatile access.</p>
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6086
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]6087<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]6088 then the caller guarantees that the source and destination pointers are
6089 aligned to that boundary.</p>
Chris Lattner4c67c482004-02-12 21:18:15 +0000[diff] [blame]6090
Jeffrey Yasskin5d284ae2010-04-26 21:21:24 +0000[diff] [blame]6091<p>If the <tt>isvolatile</tt> parameter is <tt>true</tt>, the
6092 <tt>llvm.memmove</tt> call is a <a href="#volatile">volatile operation</a>.
6093 The detailed access behavior is not very cleanly specified and it is unwise
6094 to depend on it.</p>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6095
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6096<h5>Semantics:</h5>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6097
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6098<p>The '<tt>llvm.memmove.*</tt>' intrinsics copy a block of memory from the
6099 source location to the destination location, which may overlap. It copies
6100 "len" bytes of memory over. If the argument is known to be aligned to some
6101 boundary, this can be specified as the fourth argument, otherwise it should
6102 be set to 0 or 1.</p>
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6103
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6104</div>
6105
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6106<!-- _______________________________________________________________________ -->
6107<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6108 <a name="int_memset">'<tt>llvm.memset.*</tt>' Intrinsics</a>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6109</div>
6110
6111<div class="doc_text">
6112
6113<h5>Syntax:</h5>
Chris Lattnerdd708342008-11-21 16:42:48 +0000[diff] [blame]6114<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]6115 width and for different address spaces. Not all targets support all bit
6116 widths however.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6117
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6118<pre>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6119 declare void @llvm.memset.p0i8.i32(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
Chris Lattner685db9d2010-04-08 00:54:34 +0000[diff] [blame]6120 i32 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6121 declare void @llvm.memset.p0i8.i64(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
Chris Lattner685db9d2010-04-08 00:54:34 +0000[diff] [blame]6122 i64 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6123</pre>
6124
6125<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6126<p>The '<tt>llvm.memset.*</tt>' intrinsics fill a block of memory with a
6127 particular byte value.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6128
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6129<p>Note that, unlike the standard libc function, the <tt>llvm.memset</tt>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6130 intrinsic does not return a value, takes extra alignment/volatile arguments,
6131 and the destination can be in an arbitrary address space.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6132
6133<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6134<p>The first argument is a pointer to the destination to fill, the second is the
6135 byte value to fill it with, the third argument is an integer argument
6136 specifying the number of bytes to fill, and the fourth argument is the known
6137 alignment of destination location.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6138
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]6139<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]6140 then the caller guarantees that the destination pointer is aligned to that
6141 boundary.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6142
Jeffrey Yasskin5d284ae2010-04-26 21:21:24 +0000[diff] [blame]6143<p>If the <tt>isvolatile</tt> parameter is <tt>true</tt>, the
6144 <tt>llvm.memset</tt> call is a <a href="#volatile">volatile operation</a>.
6145 The detailed access behavior is not very cleanly specified and it is unwise
6146 to depend on it.</p>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6147
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6148<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6149<p>The '<tt>llvm.memset.*</tt>' intrinsics fill "len" bytes of memory starting
6150 at the destination location. 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 Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6153
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6154</div>
6155
Chris Lattner3b4f4372004-06-11 02:28:03 +0000[diff] [blame]6156<!-- _______________________________________________________________________ -->
6157<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6158 <a name="int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a>
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]6159</div>
6160
6161<div class="doc_text">
6162
6163<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6164<p>This is an overloaded intrinsic. You can use <tt>llvm.sqrt</tt> on any
6165 floating point or vector of floating point type. Not all targets support all
6166 types however.</p>
6167
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]6168<pre>
Dale Johannesendd89d272007-10-02 17:47:38 +0000[diff] [blame]6169 declare float @llvm.sqrt.f32(float %Val)
6170 declare double @llvm.sqrt.f64(double %Val)
6171 declare x86_fp80 @llvm.sqrt.f80(x86_fp80 %Val)
6172 declare fp128 @llvm.sqrt.f128(fp128 %Val)
6173 declare ppc_fp128 @llvm.sqrt.ppcf128(ppc_fp128 %Val)
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]6174</pre>
6175
6176<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6177<p>The '<tt>llvm.sqrt</tt>' intrinsics return the sqrt of the specified operand,
6178 returning the same value as the libm '<tt>sqrt</tt>' functions would.
6179 Unlike <tt>sqrt</tt> in libm, however, <tt>llvm.sqrt</tt> has undefined
6180 behavior for negative numbers other than -0.0 (which allows for better
6181 optimization, because there is no need to worry about errno being
6182 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]6183
6184<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6185<p>The argument and return value are floating point numbers of the same
6186 type.</p>
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]6187
6188<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6189<p>This function returns the sqrt of the specified operand if it is a
6190 nonnegative floating point number.</p>
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]6191
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]6192</div>
6193
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]6194<!-- _______________________________________________________________________ -->
6195<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6196 <a name="int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a>
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]6197</div>
6198
6199<div class="doc_text">
6200
6201<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6202<p>This is an overloaded intrinsic. You can use <tt>llvm.powi</tt> on any
6203 floating point or vector of floating point type. Not all targets support all
6204 types however.</p>
6205
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]6206<pre>
Dale Johannesendd89d272007-10-02 17:47:38 +0000[diff] [blame]6207 declare float @llvm.powi.f32(float %Val, i32 %power)
6208 declare double @llvm.powi.f64(double %Val, i32 %power)
6209 declare x86_fp80 @llvm.powi.f80(x86_fp80 %Val, i32 %power)
6210 declare fp128 @llvm.powi.f128(fp128 %Val, i32 %power)
6211 declare ppc_fp128 @llvm.powi.ppcf128(ppc_fp128 %Val, i32 %power)
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]6212</pre>
6213
6214<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6215<p>The '<tt>llvm.powi.*</tt>' intrinsics return the first operand raised to the
6216 specified (positive or negative) power. The order of evaluation of
6217 multiplications is not defined. When a vector of floating point type is
6218 used, the second argument remains a scalar integer value.</p>
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]6219
6220<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6221<p>The second argument is an integer power, and the first is a value to raise to
6222 that power.</p>
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]6223
6224<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6225<p>This function returns the first value raised to the second power with an
6226 unspecified sequence of rounding operations.</p>
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]6227
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]6228</div>
6229
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6230<!-- _______________________________________________________________________ -->
6231<div class="doc_subsubsection">
6232 <a name="int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a>
6233</div>
6234
6235<div class="doc_text">
6236
6237<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6238<p>This is an overloaded intrinsic. You can use <tt>llvm.sin</tt> on any
6239 floating point or vector of floating point type. Not all targets support all
6240 types however.</p>
6241
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6242<pre>
6243 declare float @llvm.sin.f32(float %Val)
6244 declare double @llvm.sin.f64(double %Val)
6245 declare x86_fp80 @llvm.sin.f80(x86_fp80 %Val)
6246 declare fp128 @llvm.sin.f128(fp128 %Val)
6247 declare ppc_fp128 @llvm.sin.ppcf128(ppc_fp128 %Val)
6248</pre>
6249
6250<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6251<p>The '<tt>llvm.sin.*</tt>' intrinsics return the sine of the operand.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6252
6253<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6254<p>The argument and return value are floating point numbers of the same
6255 type.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6256
6257<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6258<p>This function returns the sine of the specified operand, returning the same
6259 values as the libm <tt>sin</tt> functions would, and handles error conditions
6260 in the same way.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6261
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6262</div>
6263
6264<!-- _______________________________________________________________________ -->
6265<div class="doc_subsubsection">
6266 <a name="int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a>
6267</div>
6268
6269<div class="doc_text">
6270
6271<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6272<p>This is an overloaded intrinsic. You can use <tt>llvm.cos</tt> on any
6273 floating point or vector of floating point type. Not all targets support all
6274 types however.</p>
6275
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6276<pre>
6277 declare float @llvm.cos.f32(float %Val)
6278 declare double @llvm.cos.f64(double %Val)
6279 declare x86_fp80 @llvm.cos.f80(x86_fp80 %Val)
6280 declare fp128 @llvm.cos.f128(fp128 %Val)
6281 declare ppc_fp128 @llvm.cos.ppcf128(ppc_fp128 %Val)
6282</pre>
6283
6284<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6285<p>The '<tt>llvm.cos.*</tt>' intrinsics return the cosine of the operand.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6286
6287<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6288<p>The argument and return value are floating point numbers of the same
6289 type.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6290
6291<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6292<p>This function returns the cosine of the specified operand, returning the same
6293 values as the libm <tt>cos</tt> functions would, and handles error conditions
6294 in the same way.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6295
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6296</div>
6297
6298<!-- _______________________________________________________________________ -->
6299<div class="doc_subsubsection">
6300 <a name="int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a>
6301</div>
6302
6303<div class="doc_text">
6304
6305<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6306<p>This is an overloaded intrinsic. You can use <tt>llvm.pow</tt> on any
6307 floating point or vector of floating point type. Not all targets support all
6308 types however.</p>
6309
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6310<pre>
6311 declare float @llvm.pow.f32(float %Val, float %Power)
6312 declare double @llvm.pow.f64(double %Val, double %Power)
6313 declare x86_fp80 @llvm.pow.f80(x86_fp80 %Val, x86_fp80 %Power)
6314 declare fp128 @llvm.pow.f128(fp128 %Val, fp128 %Power)
6315 declare ppc_fp128 @llvm.pow.ppcf128(ppc_fp128 %Val, ppc_fp128 Power)
6316</pre>
6317
6318<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6319<p>The '<tt>llvm.pow.*</tt>' intrinsics return the first operand raised to the
6320 specified (positive or negative) power.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6321
6322<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6323<p>The second argument is a floating point power, and the first is a value to
6324 raise to that power.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6325
6326<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6327<p>This function returns the first value raised to the second power, returning
6328 the same values as the libm <tt>pow</tt> functions would, and handles error
6329 conditions in the same way.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6330
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6331</div>
6332
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6333<!-- ======================================================================= -->
6334<div class="doc_subsection">
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]6335 <a name="int_manip">Bit Manipulation Intrinsics</a>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6336</div>
6337
6338<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6339
6340<p>LLVM provides intrinsics for a few important bit manipulation operations.
6341 These allow efficient code generation for some algorithms.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6342
6343</div>
6344
6345<!-- _______________________________________________________________________ -->
6346<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6347 <a name="int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a>
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]6348</div>
6349
6350<div class="doc_text">
6351
6352<h5>Syntax:</h5>
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]6353<p>This is an overloaded intrinsic function. You can use bswap on any integer
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6354 type that is an even number of bytes (i.e. BitWidth % 16 == 0).</p>
6355
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]6356<pre>
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]6357 declare i16 @llvm.bswap.i16(i16 &lt;id&gt;)
6358 declare i32 @llvm.bswap.i32(i32 &lt;id&gt;)
6359 declare i64 @llvm.bswap.i64(i64 &lt;id&gt;)
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]6360</pre>
6361
6362<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6363<p>The '<tt>llvm.bswap</tt>' family of intrinsics is used to byte swap integer
6364 values with an even number of bytes (positive multiple of 16 bits). These
6365 are useful for performing operations on data that is not in the target's
6366 native byte order.</p>
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]6367
6368<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6369<p>The <tt>llvm.bswap.i16</tt> intrinsic returns an i16 value that has the high
6370 and low byte of the input i16 swapped. Similarly,
6371 the <tt>llvm.bswap.i32</tt> intrinsic returns an i32 value that has the four
6372 bytes of the input i32 swapped, so that if the input bytes are numbered 0, 1,
6373 2, 3 then the returned i32 will have its bytes in 3, 2, 1, 0 order.
6374 The <tt>llvm.bswap.i48</tt>, <tt>llvm.bswap.i64</tt> and other intrinsics
6375 extend this concept to additional even-byte lengths (6 bytes, 8 bytes and
6376 more, respectively).</p>
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]6377
6378</div>
6379
6380<!-- _______________________________________________________________________ -->
6381<div class="doc_subsubsection">
Reid Spencerb4f9a6f2006-01-16 21:12:35 +0000[diff] [blame]6382 <a name="int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic</a>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6383</div>
6384
6385<div class="doc_text">
6386
6387<h5>Syntax:</h5>
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]6388<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]6389 width. Not all targets support all bit widths however.</p>
6390
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6391<pre>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6392 declare i8 @llvm.ctpop.i8(i8 &lt;src&gt;)
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]6393 declare i16 @llvm.ctpop.i16(i16 &lt;src&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]6394 declare i32 @llvm.ctpop.i32(i32 &lt;src&gt;)
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]6395 declare i64 @llvm.ctpop.i64(i64 &lt;src&gt;)
6396 declare i256 @llvm.ctpop.i256(i256 &lt;src&gt;)
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6397</pre>
6398
6399<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6400<p>The '<tt>llvm.ctpop</tt>' family of intrinsics counts the number of bits set
6401 in a value.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6402
6403<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6404<p>The only argument is the value to be counted. The argument may be of any
6405 integer type. The return type must match the argument type.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6406
6407<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6408<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]6409
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6410</div>
6411
6412<!-- _______________________________________________________________________ -->
6413<div class="doc_subsubsection">
Chris Lattnerb748c672006-01-16 22:34:14 +0000[diff] [blame]6414 <a name="int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic</a>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6415</div>
6416
6417<div class="doc_text">
6418
6419<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6420<p>This is an overloaded intrinsic. You can use <tt>llvm.ctlz</tt> on any
6421 integer bit width. Not all targets support all bit widths however.</p>
6422
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6423<pre>
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]6424 declare i8 @llvm.ctlz.i8 (i8 &lt;src&gt;)
6425 declare i16 @llvm.ctlz.i16(i16 &lt;src&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]6426 declare i32 @llvm.ctlz.i32(i32 &lt;src&gt;)
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]6427 declare i64 @llvm.ctlz.i64(i64 &lt;src&gt;)
6428 declare i256 @llvm.ctlz.i256(i256 &lt;src&gt;)
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6429</pre>
6430
6431<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6432<p>The '<tt>llvm.ctlz</tt>' family of intrinsic functions counts the number of
6433 leading zeros in a variable.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6434
6435<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6436<p>The only argument is the value to be counted. The argument may be of any
6437 integer type. The return type must match the argument type.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6438
6439<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6440<p>The '<tt>llvm.ctlz</tt>' intrinsic counts the leading (most significant)
6441 zeros in a variable. If the src == 0 then the result is the size in bits of
6442 the type of src. For example, <tt>llvm.ctlz(i32 2) = 30</tt>.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6443
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6444</div>
Chris Lattner3b4f4372004-06-11 02:28:03 +0000[diff] [blame]6445
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]6446<!-- _______________________________________________________________________ -->
6447<div class="doc_subsubsection">
Chris Lattnerb748c672006-01-16 22:34:14 +0000[diff] [blame]6448 <a name="int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic</a>
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]6449</div>
6450
6451<div class="doc_text">
6452
6453<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6454<p>This is an overloaded intrinsic. You can use <tt>llvm.cttz</tt> on any
6455 integer bit width. Not all targets support all bit widths however.</p>
6456
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]6457<pre>
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]6458 declare i8 @llvm.cttz.i8 (i8 &lt;src&gt;)
6459 declare i16 @llvm.cttz.i16(i16 &lt;src&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]6460 declare i32 @llvm.cttz.i32(i32 &lt;src&gt;)
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]6461 declare i64 @llvm.cttz.i64(i64 &lt;src&gt;)
6462 declare i256 @llvm.cttz.i256(i256 &lt;src&gt;)
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]6463</pre>
6464
6465<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6466<p>The '<tt>llvm.cttz</tt>' family of intrinsic functions counts the number of
6467 trailing zeros.</p>
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]6468
6469<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6470<p>The only argument is the value to be counted. The argument may be of any
6471 integer type. The return type must match the argument type.</p>
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]6472
6473<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6474<p>The '<tt>llvm.cttz</tt>' intrinsic counts the trailing (least significant)
6475 zeros in a variable. If the src == 0 then the result is the size in bits of
6476 the type of src. For example, <tt>llvm.cttz(2) = 1</tt>.</p>
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]6477
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]6478</div>
6479
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]6480<!-- ======================================================================= -->
6481<div class="doc_subsection">
6482 <a name="int_overflow">Arithmetic with Overflow Intrinsics</a>
6483</div>
6484
6485<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6486
6487<p>LLVM provides intrinsics for some arithmetic with overflow operations.</p>
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]6488
6489</div>
6490
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6491<!-- _______________________________________________________________________ -->
6492<div class="doc_subsubsection">
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]6493 <a name="int_sadd_overflow">'<tt>llvm.sadd.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6494</div>
6495
6496<div class="doc_text">
6497
6498<h5>Syntax:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6499<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]6500 on any integer bit width.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6501
6502<pre>
6503 declare {i16, i1} @llvm.sadd.with.overflow.i16(i16 %a, i16 %b)
6504 declare {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
6505 declare {i64, i1} @llvm.sadd.with.overflow.i64(i64 %a, i64 %b)
6506</pre>
6507
6508<h5>Overview:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6509<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6510 a signed addition of the two arguments, and indicate whether an overflow
6511 occurred during the signed summation.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6512
6513<h5>Arguments:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6514<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]6515 be of integer types of any bit width, but they must have the same bit
6516 width. The second element of the result structure must be of
6517 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6518 undergo signed addition.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6519
6520<h5>Semantics:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6521<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6522 a signed addition of the two variables. They return a structure &mdash; the
6523 first element of which is the signed summation, and the second element of
6524 which is a bit specifying if the signed summation resulted in an
6525 overflow.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6526
6527<h5>Examples:</h5>
6528<pre>
6529 %res = call {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
6530 %sum = extractvalue {i32, i1} %res, 0
6531 %obit = extractvalue {i32, i1} %res, 1
6532 br i1 %obit, label %overflow, label %normal
6533</pre>
6534
6535</div>
6536
6537<!-- _______________________________________________________________________ -->
6538<div class="doc_subsubsection">
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]6539 <a name="int_uadd_overflow">'<tt>llvm.uadd.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6540</div>
6541
6542<div class="doc_text">
6543
6544<h5>Syntax:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6545<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]6546 on any integer bit width.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6547
6548<pre>
6549 declare {i16, i1} @llvm.uadd.with.overflow.i16(i16 %a, i16 %b)
6550 declare {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
6551 declare {i64, i1} @llvm.uadd.with.overflow.i64(i64 %a, i64 %b)
6552</pre>
6553
6554<h5>Overview:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6555<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6556 an unsigned addition of the two arguments, and indicate whether a carry
6557 occurred during the unsigned summation.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6558
6559<h5>Arguments:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6560<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]6561 be of integer types of any bit width, but they must have the same bit
6562 width. The second element of the result structure must be of
6563 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6564 undergo unsigned addition.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6565
6566<h5>Semantics:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6567<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6568 an unsigned addition of the two arguments. They return a structure &mdash;
6569 the first element of which is the sum, and the second element of which is a
6570 bit specifying if the unsigned summation resulted in a carry.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6571
6572<h5>Examples:</h5>
6573<pre>
6574 %res = call {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
6575 %sum = extractvalue {i32, i1} %res, 0
6576 %obit = extractvalue {i32, i1} %res, 1
6577 br i1 %obit, label %carry, label %normal
6578</pre>
6579
6580</div>
6581
6582<!-- _______________________________________________________________________ -->
6583<div class="doc_subsubsection">
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]6584 <a name="int_ssub_overflow">'<tt>llvm.ssub.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6585</div>
6586
6587<div class="doc_text">
6588
6589<h5>Syntax:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6590<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]6591 on any integer bit width.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6592
6593<pre>
6594 declare {i16, i1} @llvm.ssub.with.overflow.i16(i16 %a, i16 %b)
6595 declare {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
6596 declare {i64, i1} @llvm.ssub.with.overflow.i64(i64 %a, i64 %b)
6597</pre>
6598
6599<h5>Overview:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6600<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6601 a signed subtraction of the two arguments, and indicate whether an overflow
6602 occurred during the signed subtraction.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6603
6604<h5>Arguments:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6605<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]6606 be of integer types of any bit width, but they must have the same bit
6607 width. The second element of the result structure must be of
6608 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6609 undergo signed subtraction.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6610
6611<h5>Semantics:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6612<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6613 a signed subtraction of the two arguments. They return a structure &mdash;
6614 the first element of which is the subtraction, and the second element of
6615 which is a bit specifying if the signed subtraction resulted in an
6616 overflow.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6617
6618<h5>Examples:</h5>
6619<pre>
6620 %res = call {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
6621 %sum = extractvalue {i32, i1} %res, 0
6622 %obit = extractvalue {i32, i1} %res, 1
6623 br i1 %obit, label %overflow, label %normal
6624</pre>
6625
6626</div>
6627
6628<!-- _______________________________________________________________________ -->
6629<div class="doc_subsubsection">
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]6630 <a name="int_usub_overflow">'<tt>llvm.usub.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6631</div>
6632
6633<div class="doc_text">
6634
6635<h5>Syntax:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6636<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]6637 on any integer bit width.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6638
6639<pre>
6640 declare {i16, i1} @llvm.usub.with.overflow.i16(i16 %a, i16 %b)
6641 declare {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
6642 declare {i64, i1} @llvm.usub.with.overflow.i64(i64 %a, i64 %b)
6643</pre>
6644
6645<h5>Overview:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6646<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6647 an unsigned subtraction of the two arguments, and indicate whether an
6648 overflow occurred during the unsigned subtraction.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6649
6650<h5>Arguments:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6651<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]6652 be of integer types of any bit width, but they must have the same bit
6653 width. The second element of the result structure must be of
6654 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6655 undergo unsigned subtraction.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6656
6657<h5>Semantics:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6658<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6659 an unsigned subtraction of the two arguments. They return a structure &mdash;
6660 the first element of which is the subtraction, and the second element of
6661 which is a bit specifying if the unsigned subtraction resulted in an
6662 overflow.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6663
6664<h5>Examples:</h5>
6665<pre>
6666 %res = call {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
6667 %sum = extractvalue {i32, i1} %res, 0
6668 %obit = extractvalue {i32, i1} %res, 1
6669 br i1 %obit, label %overflow, label %normal
6670</pre>
6671
6672</div>
6673
6674<!-- _______________________________________________________________________ -->
6675<div class="doc_subsubsection">
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]6676 <a name="int_smul_overflow">'<tt>llvm.smul.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6677</div>
6678
6679<div class="doc_text">
6680
6681<h5>Syntax:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6682<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]6683 on any integer bit width.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6684
6685<pre>
6686 declare {i16, i1} @llvm.smul.with.overflow.i16(i16 %a, i16 %b)
6687 declare {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
6688 declare {i64, i1} @llvm.smul.with.overflow.i64(i64 %a, i64 %b)
6689</pre>
6690
6691<h5>Overview:</h5>
6692
6693<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6694 a signed multiplication of the two arguments, and indicate whether an
6695 overflow occurred during the signed multiplication.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6696
6697<h5>Arguments:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6698<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]6699 be of integer types of any bit width, but they must have the same bit
6700 width. The second element of the result structure must be of
6701 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6702 undergo signed multiplication.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6703
6704<h5>Semantics:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6705<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6706 a signed multiplication of the two arguments. They return a structure &mdash;
6707 the first element of which is the multiplication, and the second element of
6708 which is a bit specifying if the signed multiplication resulted in an
6709 overflow.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6710
6711<h5>Examples:</h5>
6712<pre>
6713 %res = call {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
6714 %sum = extractvalue {i32, i1} %res, 0
6715 %obit = extractvalue {i32, i1} %res, 1
6716 br i1 %obit, label %overflow, label %normal
6717</pre>
6718
Reid Spencer5bf54c82007-04-11 23:23:49 +0000[diff] [blame]6719</div>
6720
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]6721<!-- _______________________________________________________________________ -->
6722<div class="doc_subsubsection">
6723 <a name="int_umul_overflow">'<tt>llvm.umul.with.overflow.*</tt>' Intrinsics</a>
6724</div>
6725
6726<div class="doc_text">
6727
6728<h5>Syntax:</h5>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]6729<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]6730 on any integer bit width.</p>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]6731
6732<pre>
6733 declare {i16, i1} @llvm.umul.with.overflow.i16(i16 %a, i16 %b)
6734 declare {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
6735 declare {i64, i1} @llvm.umul.with.overflow.i64(i64 %a, i64 %b)
6736</pre>
6737
6738<h5>Overview:</h5>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]6739<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6740 a unsigned multiplication of the two arguments, and indicate whether an
6741 overflow occurred during the unsigned multiplication.</p>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]6742
6743<h5>Arguments:</h5>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]6744<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]6745 be of integer types of any bit width, but they must have the same bit
6746 width. The second element of the result structure must be of
6747 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6748 undergo unsigned multiplication.</p>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]6749
6750<h5>Semantics:</h5>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]6751<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6752 an unsigned multiplication of the two arguments. They return a structure
6753 &mdash; the first element of which is the multiplication, and the second
6754 element of which is a bit specifying if the unsigned multiplication resulted
6755 in an overflow.</p>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]6756
6757<h5>Examples:</h5>
6758<pre>
6759 %res = call {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
6760 %sum = extractvalue {i32, i1} %res, 0
6761 %obit = extractvalue {i32, i1} %res, 1
6762 br i1 %obit, label %overflow, label %normal
6763</pre>
6764
6765</div>
6766
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]6767<!-- ======================================================================= -->
6768<div class="doc_subsection">
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]6769 <a name="int_fp16">Half Precision Floating Point Intrinsics</a>
6770</div>
6771
6772<div class="doc_text">
6773
Chris Lattner022a9fb2010-03-15 04:12:21 +0000[diff] [blame]6774<p>Half precision floating point is a storage-only format. This means that it is
6775 a dense encoding (in memory) but does not support computation in the
6776 format.</p>
Chris Lattnerbbd8bd32010-03-14 23:03:31 +0000[diff] [blame]6777
Chris Lattner022a9fb2010-03-15 04:12:21 +0000[diff] [blame]6778<p>This means that code must first load the half-precision floating point
Chris Lattnerbbd8bd32010-03-14 23:03:31 +0000[diff] [blame]6779 value as an i16, then convert it to float with <a
6780 href="#int_convert_from_fp16"><tt>llvm.convert.from.fp16</tt></a>.
6781 Computation can then be performed on the float value (including extending to
Chris Lattner022a9fb2010-03-15 04:12:21 +0000[diff] [blame]6782 double etc). To store the value back to memory, it is first converted to
6783 float if needed, then converted to i16 with
Chris Lattnerbbd8bd32010-03-14 23:03:31 +0000[diff] [blame]6784 <a href="#int_convert_to_fp16"><tt>llvm.convert.to.fp16</tt></a>, then
6785 storing as an i16 value.</p>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]6786</div>
6787
6788<!-- _______________________________________________________________________ -->
6789<div class="doc_subsubsection">
Chris Lattnerbbd8bd32010-03-14 23:03:31 +0000[diff] [blame]6790 <a name="int_convert_to_fp16">'<tt>llvm.convert.to.fp16</tt>' Intrinsic</a>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]6791</div>
6792
6793<div class="doc_text">
6794
6795<h5>Syntax:</h5>
6796<pre>
6797 declare i16 @llvm.convert.to.fp16(f32 %a)
6798</pre>
6799
6800<h5>Overview:</h5>
6801<p>The '<tt>llvm.convert.to.fp16</tt>' intrinsic function performs
6802 a conversion from single precision floating point format to half precision
6803 floating point format.</p>
6804
6805<h5>Arguments:</h5>
6806<p>The intrinsic function contains single argument - the value to be
6807 converted.</p>
6808
6809<h5>Semantics:</h5>
6810<p>The '<tt>llvm.convert.to.fp16</tt>' intrinsic function performs
6811 a conversion from single precision floating point format to half precision
Chris Lattner022a9fb2010-03-15 04:12:21 +0000[diff] [blame]6812 floating point format. The return value is an <tt>i16</tt> which
Chris Lattnerbbd8bd32010-03-14 23:03:31 +0000[diff] [blame]6813 contains the converted number.</p>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]6814
6815<h5>Examples:</h5>
6816<pre>
6817 %res = call i16 @llvm.convert.to.fp16(f32 %a)
6818 store i16 %res, i16* @x, align 2
6819</pre>
6820
6821</div>
6822
6823<!-- _______________________________________________________________________ -->
6824<div class="doc_subsubsection">
Chris Lattnerbbd8bd32010-03-14 23:03:31 +0000[diff] [blame]6825 <a name="int_convert_from_fp16">'<tt>llvm.convert.from.fp16</tt>' Intrinsic</a>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]6826</div>
6827
6828<div class="doc_text">
6829
6830<h5>Syntax:</h5>
6831<pre>
6832 declare f32 @llvm.convert.from.fp16(i16 %a)
6833</pre>
6834
6835<h5>Overview:</h5>
6836<p>The '<tt>llvm.convert.from.fp16</tt>' intrinsic function performs
6837 a conversion from half precision floating point format to single precision
6838 floating point format.</p>
6839
6840<h5>Arguments:</h5>
6841<p>The intrinsic function contains single argument - the value to be
6842 converted.</p>
6843
6844<h5>Semantics:</h5>
6845<p>The '<tt>llvm.convert.from.fp16</tt>' intrinsic function performs a
Chris Lattner022a9fb2010-03-15 04:12:21 +0000[diff] [blame]6846 conversion from half single precision floating point format to single
Chris Lattnerbbd8bd32010-03-14 23:03:31 +0000[diff] [blame]6847 precision floating point format. The input half-float value is represented by
6848 an <tt>i16</tt> value.</p>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]6849
6850<h5>Examples:</h5>
6851<pre>
6852 %a = load i16* @x, align 2
6853 %res = call f32 @llvm.convert.from.fp16(i16 %a)
6854</pre>
6855
6856</div>
6857
6858<!-- ======================================================================= -->
6859<div class="doc_subsection">
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]6860 <a name="int_debugger">Debugger Intrinsics</a>
6861</div>
6862
6863<div class="doc_text">
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]6864
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6865<p>The LLVM debugger intrinsics (which all start with <tt>llvm.dbg.</tt>
6866 prefix), are described in
6867 the <a href="SourceLevelDebugging.html#format_common_intrinsics">LLVM Source
6868 Level Debugging</a> document.</p>
6869
6870</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]6871
Jim Laskey2211f492007-03-14 19:31:19 +0000[diff] [blame]6872<!-- ======================================================================= -->
6873<div class="doc_subsection">
6874 <a name="int_eh">Exception Handling Intrinsics</a>
6875</div>
6876
6877<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6878
6879<p>The LLVM exception handling intrinsics (which all start with
6880 <tt>llvm.eh.</tt> prefix), are described in
6881 the <a href="ExceptionHandling.html#format_common_intrinsics">LLVM Exception
6882 Handling</a> document.</p>
6883
Jim Laskey2211f492007-03-14 19:31:19 +0000[diff] [blame]6884</div>
6885
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]6886<!-- ======================================================================= -->
6887<div class="doc_subsection">
Duncan Sands86e01192007-09-11 14:10:23 +0000[diff] [blame]6888 <a name="int_trampoline">Trampoline Intrinsic</a>
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]6889</div>
6890
6891<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6892
6893<p>This intrinsic makes it possible to excise one parameter, marked with
6894 the <tt>nest</tt> attribute, from a function. The result is a callable
6895 function pointer lacking the nest parameter - the caller does not need to
6896 provide a value for it. Instead, the value to use is stored in advance in a
6897 "trampoline", a block of memory usually allocated on the stack, which also
6898 contains code to splice the nest value into the argument list. This is used
6899 to implement the GCC nested function address extension.</p>
6900
6901<p>For example, if the function is
6902 <tt>i32 f(i8* nest %c, i32 %x, i32 %y)</tt> then the resulting function
6903 pointer has signature <tt>i32 (i32, i32)*</tt>. It can be created as
6904 follows:</p>
6905
6906<div class="doc_code">
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]6907<pre>
Duncan Sands86e01192007-09-11 14:10:23 +0000[diff] [blame]6908 %tramp = alloca [10 x i8], align 4 ; size and alignment only correct for X86
6909 %tramp1 = getelementptr [10 x i8]* %tramp, i32 0, i32 0
6910 %p = call i8* @llvm.init.trampoline( i8* %tramp1, i8* bitcast (i32 (i8* nest , i32, i32)* @f to i8*), i8* %nval )
6911 %fp = bitcast i8* %p to i32 (i32, i32)*
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]6912</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6913</div>
6914
6915<p>The call <tt>%val = call i32 %fp( i32 %x, i32 %y )</tt> is then equivalent
6916 to <tt>%val = call i32 %f( i8* %nval, i32 %x, i32 %y )</tt>.</p>
6917
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]6918</div>
6919
6920<!-- _______________________________________________________________________ -->
6921<div class="doc_subsubsection">
6922 <a name="int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a>
6923</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6924
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]6925<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6926
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]6927<h5>Syntax:</h5>
6928<pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6929 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]6930</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6931
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]6932<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6933<p>This fills the memory pointed to by <tt>tramp</tt> with code and returns a
6934 function pointer suitable for executing it.</p>
6935
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]6936<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6937<p>The <tt>llvm.init.trampoline</tt> intrinsic takes three arguments, all
6938 pointers. The <tt>tramp</tt> argument must point to a sufficiently large and
6939 sufficiently aligned block of memory; this memory is written to by the
6940 intrinsic. Note that the size and the alignment are target-specific - LLVM
6941 currently provides no portable way of determining them, so a front-end that
6942 generates this intrinsic needs to have some target-specific knowledge.
6943 The <tt>func</tt> argument must hold a function bitcast to
6944 an <tt>i8*</tt>.</p>
6945
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]6946<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6947<p>The block of memory pointed to by <tt>tramp</tt> is filled with target
6948 dependent code, turning it into a function. A pointer to this function is
6949 returned, but needs to be bitcast to an <a href="#int_trampoline">appropriate
6950 function pointer type</a> before being called. The new function's signature
6951 is the same as that of <tt>func</tt> with any arguments marked with
6952 the <tt>nest</tt> attribute removed. At most one such <tt>nest</tt> argument
6953 is allowed, and it must be of pointer type. Calling the new function is
6954 equivalent to calling <tt>func</tt> with the same argument list, but
6955 with <tt>nval</tt> used for the missing <tt>nest</tt> argument. If, after
6956 calling <tt>llvm.init.trampoline</tt>, the memory pointed to
6957 by <tt>tramp</tt> is modified, then the effect of any later call to the
6958 returned function pointer is undefined.</p>
6959
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]6960</div>
6961
6962<!-- ======================================================================= -->
6963<div class="doc_subsection">
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]6964 <a name="int_atomics">Atomic Operations and Synchronization Intrinsics</a>
6965</div>
6966
6967<div class="doc_text">
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]6968
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6969<p>These intrinsic functions expand the "universal IR" of LLVM to represent
6970 hardware constructs for atomic operations and memory synchronization. This
6971 provides an interface to the hardware, not an interface to the programmer. It
6972 is aimed at a low enough level to allow any programming models or APIs
6973 (Application Programming Interfaces) which need atomic behaviors to map
6974 cleanly onto it. It is also modeled primarily on hardware behavior. Just as
6975 hardware provides a "universal IR" for source languages, it also provides a
6976 starting point for developing a "universal" atomic operation and
6977 synchronization IR.</p>
6978
6979<p>These do <em>not</em> form an API such as high-level threading libraries,
6980 software transaction memory systems, atomic primitives, and intrinsic
6981 functions as found in BSD, GNU libc, atomic_ops, APR, and other system and
6982 application libraries. The hardware interface provided by LLVM should allow
6983 a clean implementation of all of these APIs and parallel programming models.
6984 No one model or paradigm should be selected above others unless the hardware
6985 itself ubiquitously does so.</p>
6986
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]6987</div>
6988
6989<!-- _______________________________________________________________________ -->
6990<div class="doc_subsubsection">
6991 <a name="int_memory_barrier">'<tt>llvm.memory.barrier</tt>' Intrinsic</a>
6992</div>
6993<div class="doc_text">
6994<h5>Syntax:</h5>
6995<pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6996 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]6997</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6998
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]6999<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7000<p>The <tt>llvm.memory.barrier</tt> intrinsic guarantees ordering between
7001 specific pairs of memory access types.</p>
7002
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7003<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7004<p>The <tt>llvm.memory.barrier</tt> intrinsic requires five boolean arguments.
7005 The first four arguments enables a specific barrier as listed below. The
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]7006 fifth argument specifies that the barrier applies to io or device or uncached
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7007 memory.</p>
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7008
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7009<ul>
7010 <li><tt>ll</tt>: load-load barrier</li>
7011 <li><tt>ls</tt>: load-store barrier</li>
7012 <li><tt>sl</tt>: store-load barrier</li>
7013 <li><tt>ss</tt>: store-store barrier</li>
7014 <li><tt>device</tt>: barrier applies to device and uncached memory also.</li>
7015</ul>
7016
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7017<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7018<p>This intrinsic causes the system to enforce some ordering constraints upon
7019 the loads and stores of the program. This barrier does not
7020 indicate <em>when</em> any events will occur, it only enforces
7021 an <em>order</em> in which they occur. For any of the specified pairs of load
7022 and store operations (f.ex. load-load, or store-load), all of the first
7023 operations preceding the barrier will complete before any of the second
7024 operations succeeding the barrier begin. Specifically the semantics for each
7025 pairing is as follows:</p>
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7026
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7027<ul>
7028 <li><tt>ll</tt>: All loads before the barrier must complete before any load
7029 after the barrier begins.</li>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]7030 <li><tt>ls</tt>: All loads before the barrier must complete before any
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7031 store after the barrier begins.</li>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]7032 <li><tt>ss</tt>: All stores before the barrier must complete before any
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7033 store after the barrier begins.</li>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]7034 <li><tt>sl</tt>: All stores before the barrier must complete before any
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7035 load after the barrier begins.</li>
7036</ul>
7037
7038<p>These semantics are applied with a logical "and" behavior when more than one
7039 is enabled in a single memory barrier intrinsic.</p>
7040
7041<p>Backends may implement stronger barriers than those requested when they do
7042 not support as fine grained a barrier as requested. Some architectures do
7043 not need all types of barriers and on such architectures, these become
7044 noops.</p>
7045
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7046<h5>Example:</h5>
7047<pre>
Victor Hernandeza70c6df2009-10-26 23:44:29 +0000[diff] [blame]7048%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7049%ptr = bitcast i8* %mallocP to i32*
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7050 store i32 4, %ptr
7051
7052%result1 = load i32* %ptr <i>; yields {i32}:result1 = 4</i>
7053 call void @llvm.memory.barrier( i1 false, i1 true, i1 false, i1 false )
7054 <i>; guarantee the above finishes</i>
7055 store i32 8, %ptr <i>; before this begins</i>
7056</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7057
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7058</div>
7059
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7060<!-- _______________________________________________________________________ -->
7061<div class="doc_subsubsection">
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7062 <a name="int_atomic_cmp_swap">'<tt>llvm.atomic.cmp.swap.*</tt>' Intrinsic</a>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7063</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7064
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7065<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7066
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7067<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7068<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.cmp.swap</tt> on
7069 any integer bit width and for different address spaces. Not all targets
7070 support all bit widths however.</p>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7071
7072<pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7073 declare i8 @llvm.atomic.cmp.swap.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;cmp&gt;, i8 &lt;val&gt; )
7074 declare i16 @llvm.atomic.cmp.swap.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;cmp&gt;, i16 &lt;val&gt; )
7075 declare i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;cmp&gt;, i32 &lt;val&gt; )
7076 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]7077</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7078
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7079<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7080<p>This loads a value in memory and compares it to a given value. If they are
7081 equal, it stores a new value into the memory.</p>
7082
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7083<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7084<p>The <tt>llvm.atomic.cmp.swap</tt> intrinsic takes three arguments. The result
7085 as well as both <tt>cmp</tt> and <tt>val</tt> must be integer values with the
7086 same bit width. The <tt>ptr</tt> argument must be a pointer to a value of
7087 this integer type. While any bit width integer may be used, targets may only
7088 lower representations they support in hardware.</p>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7089
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7090<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7091<p>This entire intrinsic must be executed atomically. It first loads the value
7092 in memory pointed to by <tt>ptr</tt> and compares it with the
7093 value <tt>cmp</tt>. If they are equal, <tt>val</tt> is stored into the
7094 memory. The loaded value is yielded in all cases. This provides the
7095 equivalent of an atomic compare-and-swap operation within the SSA
7096 framework.</p>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7097
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7098<h5>Examples:</h5>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7099<pre>
Victor Hernandeza70c6df2009-10-26 23:44:29 +0000[diff] [blame]7100%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7101%ptr = bitcast i8* %mallocP to i32*
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7102 store i32 4, %ptr
7103
7104%val1 = add i32 4, 4
Mon P Wang2c839d42008-07-30 04:36:53 +0000[diff] [blame]7105%result1 = call i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* %ptr, i32 4, %val1 )
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7106 <i>; yields {i32}:result1 = 4</i>
7107%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
7108%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
7109
7110%val2 = add i32 1, 1
Mon P Wang2c839d42008-07-30 04:36:53 +0000[diff] [blame]7111%result2 = call i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* %ptr, i32 5, %val2 )
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7112 <i>; yields {i32}:result2 = 8</i>
7113%stored2 = icmp eq i32 %result2, 5 <i>; yields {i1}:stored2 = false</i>
7114
7115%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 8</i>
7116</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7117
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7118</div>
7119
7120<!-- _______________________________________________________________________ -->
7121<div class="doc_subsubsection">
7122 <a name="int_atomic_swap">'<tt>llvm.atomic.swap.*</tt>' Intrinsic</a>
7123</div>
7124<div class="doc_text">
7125<h5>Syntax:</h5>
7126
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7127<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.swap</tt> on any
7128 integer bit width. Not all targets support all bit widths however.</p>
7129
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7130<pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7131 declare i8 @llvm.atomic.swap.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;val&gt; )
7132 declare i16 @llvm.atomic.swap.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;val&gt; )
7133 declare i32 @llvm.atomic.swap.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;val&gt; )
7134 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]7135</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7136
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7137<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7138<p>This intrinsic loads the value stored in memory at <tt>ptr</tt> and yields
7139 the value from memory. It then stores the value in <tt>val</tt> in the memory
7140 at <tt>ptr</tt>.</p>
7141
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7142<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7143<p>The <tt>llvm.atomic.swap</tt> intrinsic takes two arguments. Both
7144 the <tt>val</tt> argument and the result must be integers of the same bit
7145 width. The first argument, <tt>ptr</tt>, must be a pointer to a value of this
7146 integer type. The targets may only lower integer representations they
7147 support.</p>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7148
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7149<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7150<p>This intrinsic loads the value pointed to by <tt>ptr</tt>, yields it, and
7151 stores <tt>val</tt> back into <tt>ptr</tt> atomically. This provides the
7152 equivalent of an atomic swap operation within the SSA framework.</p>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7153
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7154<h5>Examples:</h5>
7155<pre>
Victor Hernandeza70c6df2009-10-26 23:44:29 +0000[diff] [blame]7156%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7157%ptr = bitcast i8* %mallocP to i32*
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7158 store i32 4, %ptr
7159
7160%val1 = add i32 4, 4
Mon P Wang2c839d42008-07-30 04:36:53 +0000[diff] [blame]7161%result1 = call i32 @llvm.atomic.swap.i32.p0i32( i32* %ptr, i32 %val1 )
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7162 <i>; yields {i32}:result1 = 4</i>
7163%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
7164%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
7165
7166%val2 = add i32 1, 1
Mon P Wang2c839d42008-07-30 04:36:53 +0000[diff] [blame]7167%result2 = call i32 @llvm.atomic.swap.i32.p0i32( i32* %ptr, i32 %val2 )
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7168 <i>; yields {i32}:result2 = 8</i>
7169
7170%stored2 = icmp eq i32 %result2, 8 <i>; yields {i1}:stored2 = true</i>
7171%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 2</i>
7172</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7173
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7174</div>
7175
7176<!-- _______________________________________________________________________ -->
7177<div class="doc_subsubsection">
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7178 <a name="int_atomic_load_add">'<tt>llvm.atomic.load.add.*</tt>' Intrinsic</a>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7179
7180</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7181
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7182<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7183
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7184<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7185<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.load.add</tt> on
7186 any integer bit width. Not all targets support all bit widths however.</p>
7187
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7188<pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7189 declare i8 @llvm.atomic.load.add.i8..p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
7190 declare i16 @llvm.atomic.load.add.i16..p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
7191 declare i32 @llvm.atomic.load.add.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
7192 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]7193</pre>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7194
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7195<h5>Overview:</h5>
7196<p>This intrinsic adds <tt>delta</tt> to the value stored in memory
7197 at <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.</p>
7198
7199<h5>Arguments:</h5>
7200<p>The intrinsic takes two arguments, the first a pointer to an integer value
7201 and the second an integer value. The result is also an integer value. These
7202 integer types can have any bit width, but they must all have the same bit
7203 width. The targets may only lower integer representations they support.</p>
7204
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7205<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7206<p>This intrinsic does a series of operations atomically. It first loads the
7207 value stored at <tt>ptr</tt>. It then adds <tt>delta</tt>, stores the result
7208 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]7209
7210<h5>Examples:</h5>
7211<pre>
Victor Hernandeza70c6df2009-10-26 23:44:29 +0000[diff] [blame]7212%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7213%ptr = bitcast i8* %mallocP to i32*
7214 store i32 4, %ptr
Mon P Wang2c839d42008-07-30 04:36:53 +0000[diff] [blame]7215%result1 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 4 )
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7216 <i>; yields {i32}:result1 = 4</i>
Mon P Wang2c839d42008-07-30 04:36:53 +0000[diff] [blame]7217%result2 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 2 )
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7218 <i>; yields {i32}:result2 = 8</i>
Mon P Wang2c839d42008-07-30 04:36:53 +0000[diff] [blame]7219%result3 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 5 )
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7220 <i>; yields {i32}:result3 = 10</i>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7221%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 15</i>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]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
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7226<!-- _______________________________________________________________________ -->
7227<div class="doc_subsubsection">
7228 <a name="int_atomic_load_sub">'<tt>llvm.atomic.load.sub.*</tt>' Intrinsic</a>
7229
7230</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7231
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7232<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7233
Mon P Wang6a490372008-06-25 08:15:39 +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.sub</tt> on
7236 any integer bit width and for different address spaces. Not all targets
7237 support all bit widths however.</p>
7238
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7239<pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7240 declare i8 @llvm.atomic.load.sub.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
7241 declare i16 @llvm.atomic.load.sub.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
7242 declare i32 @llvm.atomic.load.sub.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
7243 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]7244</pre>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7245
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7246<h5>Overview:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]7247<p>This intrinsic subtracts <tt>delta</tt> to the value stored in memory at
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7248 <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.</p>
7249
7250<h5>Arguments:</h5>
7251<p>The intrinsic takes two arguments, the first a pointer to an integer value
7252 and the second an integer value. The result is also an integer value. These
7253 integer types can have any bit width, but they must all have the same bit
7254 width. The targets may only lower integer representations they support.</p>
7255
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7256<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7257<p>This intrinsic does a series of operations atomically. It first loads the
7258 value stored at <tt>ptr</tt>. It then subtracts <tt>delta</tt>, stores the
7259 result to <tt>ptr</tt>. It yields the original value stored
7260 at <tt>ptr</tt>.</p>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7261
7262<h5>Examples:</h5>
7263<pre>
Victor Hernandeza70c6df2009-10-26 23:44:29 +0000[diff] [blame]7264%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7265%ptr = bitcast i8* %mallocP to i32*
7266 store i32 8, %ptr
Mon P Wang2c839d42008-07-30 04:36:53 +0000[diff] [blame]7267%result1 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 4 )
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7268 <i>; yields {i32}:result1 = 8</i>
Mon P Wang2c839d42008-07-30 04:36:53 +0000[diff] [blame]7269%result2 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 2 )
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7270 <i>; yields {i32}:result2 = 4</i>
Mon P Wang2c839d42008-07-30 04:36:53 +0000[diff] [blame]7271%result3 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 5 )
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7272 <i>; yields {i32}:result3 = 2</i>
7273%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = -3</i>
7274</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7275
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7276</div>
7277
7278<!-- _______________________________________________________________________ -->
7279<div class="doc_subsubsection">
7280 <a name="int_atomic_load_and">'<tt>llvm.atomic.load.and.*</tt>' Intrinsic</a><br>
7281 <a name="int_atomic_load_nand">'<tt>llvm.atomic.load.nand.*</tt>' Intrinsic</a><br>
7282 <a name="int_atomic_load_or">'<tt>llvm.atomic.load.or.*</tt>' Intrinsic</a><br>
7283 <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]7284</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7285
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7286<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7287
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7288<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7289<p>These are overloaded intrinsics. You can
7290 use <tt>llvm.atomic.load_and</tt>, <tt>llvm.atomic.load_nand</tt>,
7291 <tt>llvm.atomic.load_or</tt>, and <tt>llvm.atomic.load_xor</tt> on any integer
7292 bit width and for different address spaces. Not all targets support all bit
7293 widths however.</p>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7294
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7295<pre>
7296 declare i8 @llvm.atomic.load.and.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
7297 declare i16 @llvm.atomic.load.and.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
7298 declare i32 @llvm.atomic.load.and.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
7299 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]7300</pre>
7301
7302<pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7303 declare i8 @llvm.atomic.load.or.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
7304 declare i16 @llvm.atomic.load.or.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
7305 declare i32 @llvm.atomic.load.or.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
7306 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]7307</pre>
7308
7309<pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7310 declare i8 @llvm.atomic.load.nand.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
7311 declare i16 @llvm.atomic.load.nand.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
7312 declare i32 @llvm.atomic.load.nand.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
7313 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]7314</pre>
7315
7316<pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7317 declare i8 @llvm.atomic.load.xor.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
7318 declare i16 @llvm.atomic.load.xor.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
7319 declare i32 @llvm.atomic.load.xor.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
7320 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]7321</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7322
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7323<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7324<p>These intrinsics bitwise the operation (and, nand, or, xor) <tt>delta</tt> to
7325 the value stored in memory at <tt>ptr</tt>. It yields the original value
7326 at <tt>ptr</tt>.</p>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7327
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7328<h5>Arguments:</h5>
7329<p>These intrinsics take two arguments, the first a pointer to an integer value
7330 and the second an integer value. The result is also an integer value. These
7331 integer types can have any bit width, but they must all have the same bit
7332 width. The targets may only lower integer representations they support.</p>
7333
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7334<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7335<p>These intrinsics does a series of operations atomically. They first load the
7336 value stored at <tt>ptr</tt>. They then do the bitwise
7337 operation <tt>delta</tt>, store the result to <tt>ptr</tt>. They yield the
7338 original value stored at <tt>ptr</tt>.</p>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7339
7340<h5>Examples:</h5>
7341<pre>
Victor Hernandeza70c6df2009-10-26 23:44:29 +0000[diff] [blame]7342%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7343%ptr = bitcast i8* %mallocP to i32*
7344 store i32 0x0F0F, %ptr
Mon P Wang2c839d42008-07-30 04:36:53 +0000[diff] [blame]7345%result0 = call i32 @llvm.atomic.load.nand.i32.p0i32( i32* %ptr, i32 0xFF )
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7346 <i>; yields {i32}:result0 = 0x0F0F</i>
Mon P Wang2c839d42008-07-30 04:36:53 +0000[diff] [blame]7347%result1 = call i32 @llvm.atomic.load.and.i32.p0i32( i32* %ptr, i32 0xFF )
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7348 <i>; yields {i32}:result1 = 0xFFFFFFF0</i>
Mon P Wang2c839d42008-07-30 04:36:53 +0000[diff] [blame]7349%result2 = call i32 @llvm.atomic.load.or.i32.p0i32( i32* %ptr, i32 0F )
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7350 <i>; yields {i32}:result2 = 0xF0</i>
Mon P Wang2c839d42008-07-30 04:36:53 +0000[diff] [blame]7351%result3 = call i32 @llvm.atomic.load.xor.i32.p0i32( i32* %ptr, i32 0F )
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7352 <i>; yields {i32}:result3 = FF</i>
7353%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = F0</i>
7354</pre>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7355
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7356</div>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7357
7358<!-- _______________________________________________________________________ -->
7359<div class="doc_subsubsection">
7360 <a name="int_atomic_load_max">'<tt>llvm.atomic.load.max.*</tt>' Intrinsic</a><br>
7361 <a name="int_atomic_load_min">'<tt>llvm.atomic.load.min.*</tt>' Intrinsic</a><br>
7362 <a name="int_atomic_load_umax">'<tt>llvm.atomic.load.umax.*</tt>' Intrinsic</a><br>
7363 <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]7364</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7365
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7366<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7367
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7368<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7369<p>These are overloaded intrinsics. You can use <tt>llvm.atomic.load_max</tt>,
7370 <tt>llvm.atomic.load_min</tt>, <tt>llvm.atomic.load_umax</tt>, and
7371 <tt>llvm.atomic.load_umin</tt> on any integer bit width and for different
7372 address spaces. Not all targets support all bit widths however.</p>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7373
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7374<pre>
7375 declare i8 @llvm.atomic.load.max.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
7376 declare i16 @llvm.atomic.load.max.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
7377 declare i32 @llvm.atomic.load.max.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
7378 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]7379</pre>
7380
7381<pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7382 declare i8 @llvm.atomic.load.min.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
7383 declare i16 @llvm.atomic.load.min.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
7384 declare i32 @llvm.atomic.load.min.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
7385 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]7386</pre>
7387
7388<pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7389 declare i8 @llvm.atomic.load.umax.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
7390 declare i16 @llvm.atomic.load.umax.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
7391 declare i32 @llvm.atomic.load.umax.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
7392 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]7393</pre>
7394
7395<pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7396 declare i8 @llvm.atomic.load.umin.i8..p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
7397 declare i16 @llvm.atomic.load.umin.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
7398 declare i32 @llvm.atomic.load.umin.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
7399 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]7400</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7401
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7402<h5>Overview:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]7403<p>These intrinsics takes the signed or unsigned minimum or maximum of
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7404 <tt>delta</tt> and the value stored in memory at <tt>ptr</tt>. It yields the
7405 original value at <tt>ptr</tt>.</p>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7406
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7407<h5>Arguments:</h5>
7408<p>These intrinsics take two arguments, the first a pointer to an integer value
7409 and the second an integer value. The result is also an integer value. These
7410 integer types can have any bit width, but they must all have the same bit
7411 width. The targets may only lower integer representations they support.</p>
7412
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7413<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7414<p>These intrinsics does a series of operations atomically. They first load the
7415 value stored at <tt>ptr</tt>. They then do the signed or unsigned min or
7416 max <tt>delta</tt> and the value, store the result to <tt>ptr</tt>. They
7417 yield the original value stored at <tt>ptr</tt>.</p>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7418
7419<h5>Examples:</h5>
7420<pre>
Victor Hernandeza70c6df2009-10-26 23:44:29 +0000[diff] [blame]7421%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7422%ptr = bitcast i8* %mallocP to i32*
7423 store i32 7, %ptr
Mon P Wang2c839d42008-07-30 04:36:53 +0000[diff] [blame]7424%result0 = call i32 @llvm.atomic.load.min.i32.p0i32( i32* %ptr, i32 -2 )
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7425 <i>; yields {i32}:result0 = 7</i>
Mon P Wang2c839d42008-07-30 04:36:53 +0000[diff] [blame]7426%result1 = call i32 @llvm.atomic.load.max.i32.p0i32( i32* %ptr, i32 8 )
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7427 <i>; yields {i32}:result1 = -2</i>
Mon P Wang2c839d42008-07-30 04:36:53 +0000[diff] [blame]7428%result2 = call i32 @llvm.atomic.load.umin.i32.p0i32( i32* %ptr, i32 10 )
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7429 <i>; yields {i32}:result2 = 8</i>
Mon P Wang2c839d42008-07-30 04:36:53 +0000[diff] [blame]7430%result3 = call i32 @llvm.atomic.load.umax.i32.p0i32( i32* %ptr, i32 30 )
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7431 <i>; yields {i32}:result3 = 8</i>
7432%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 30</i>
7433</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7434
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7435</div>
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7436
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]7437
7438<!-- ======================================================================= -->
7439<div class="doc_subsection">
7440 <a name="int_memorymarkers">Memory Use Markers</a>
7441</div>
7442
7443<div class="doc_text">
7444
7445<p>This class of intrinsics exists to information about the lifetime of memory
7446 objects and ranges where variables are immutable.</p>
7447
7448</div>
7449
7450<!-- _______________________________________________________________________ -->
7451<div class="doc_subsubsection">
7452 <a name="int_lifetime_start">'<tt>llvm.lifetime.start</tt>' Intrinsic</a>
7453</div>
7454
7455<div class="doc_text">
7456
7457<h5>Syntax:</h5>
7458<pre>
7459 declare void @llvm.lifetime.start(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7460</pre>
7461
7462<h5>Overview:</h5>
7463<p>The '<tt>llvm.lifetime.start</tt>' intrinsic specifies the start of a memory
7464 object's lifetime.</p>
7465
7466<h5>Arguments:</h5>
Nick Lewycky9bc89042009-10-13 07:57:33 +0000[diff] [blame]7467<p>The first argument is a constant integer representing the size of the
7468 object, or -1 if it is variable sized. The second argument is a pointer to
7469 the object.</p>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]7470
7471<h5>Semantics:</h5>
7472<p>This intrinsic indicates that before this point in the code, the value of the
7473 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]7474 never be used and has an undefined value. A load from the pointer that
7475 precedes this intrinsic can be replaced with
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]7476 <tt>'<a href="#undefvalues">undef</a>'</tt>.</p>
7477
7478</div>
7479
7480<!-- _______________________________________________________________________ -->
7481<div class="doc_subsubsection">
7482 <a name="int_lifetime_end">'<tt>llvm.lifetime.end</tt>' Intrinsic</a>
7483</div>
7484
7485<div class="doc_text">
7486
7487<h5>Syntax:</h5>
7488<pre>
7489 declare void @llvm.lifetime.end(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7490</pre>
7491
7492<h5>Overview:</h5>
7493<p>The '<tt>llvm.lifetime.end</tt>' intrinsic specifies the end of a memory
7494 object's lifetime.</p>
7495
7496<h5>Arguments:</h5>
Nick Lewycky9bc89042009-10-13 07:57:33 +0000[diff] [blame]7497<p>The first argument is a constant integer representing the size of the
7498 object, or -1 if it is variable sized. The second argument is a pointer to
7499 the object.</p>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]7500
7501<h5>Semantics:</h5>
7502<p>This intrinsic indicates that after this point in the code, the value of the
7503 memory pointed to by <tt>ptr</tt> is dead. This means that it is known to
7504 never be used and has an undefined value. Any stores into the memory object
7505 following this intrinsic may be removed as dead.
7506
7507</div>
7508
7509<!-- _______________________________________________________________________ -->
7510<div class="doc_subsubsection">
7511 <a name="int_invariant_start">'<tt>llvm.invariant.start</tt>' Intrinsic</a>
7512</div>
7513
7514<div class="doc_text">
7515
7516<h5>Syntax:</h5>
7517<pre>
7518 declare {}* @llvm.invariant.start(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;) readonly
7519</pre>
7520
7521<h5>Overview:</h5>
7522<p>The '<tt>llvm.invariant.start</tt>' intrinsic specifies that the contents of
7523 a memory object will not change.</p>
7524
7525<h5>Arguments:</h5>
Nick Lewycky9bc89042009-10-13 07:57:33 +0000[diff] [blame]7526<p>The first argument is a constant integer representing the size of the
7527 object, or -1 if it is variable sized. The second argument is a pointer to
7528 the object.</p>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]7529
7530<h5>Semantics:</h5>
7531<p>This intrinsic indicates that until an <tt>llvm.invariant.end</tt> that uses
7532 the return value, the referenced memory location is constant and
7533 unchanging.</p>
7534
7535</div>
7536
7537<!-- _______________________________________________________________________ -->
7538<div class="doc_subsubsection">
7539 <a name="int_invariant_end">'<tt>llvm.invariant.end</tt>' Intrinsic</a>
7540</div>
7541
7542<div class="doc_text">
7543
7544<h5>Syntax:</h5>
7545<pre>
7546 declare void @llvm.invariant.end({}* &lt;start&gt;, i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7547</pre>
7548
7549<h5>Overview:</h5>
7550<p>The '<tt>llvm.invariant.end</tt>' intrinsic specifies that the contents of
7551 a memory object are mutable.</p>
7552
7553<h5>Arguments:</h5>
7554<p>The first argument is the matching <tt>llvm.invariant.start</tt> intrinsic.
Nick Lewycky9bc89042009-10-13 07:57:33 +0000[diff] [blame]7555 The second argument is a constant integer representing the size of the
7556 object, or -1 if it is variable sized and the third argument is a pointer
7557 to the object.</p>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]7558
7559<h5>Semantics:</h5>
7560<p>This intrinsic indicates that the memory is mutable again.</p>
7561
7562</div>
7563
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7564<!-- ======================================================================= -->
7565<div class="doc_subsection">
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]7566 <a name="int_general">General Intrinsics</a>
7567</div>
7568
7569<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7570
7571<p>This class of intrinsics is designed to be generic and has no specific
7572 purpose.</p>
7573
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]7574</div>
7575
7576<!-- _______________________________________________________________________ -->
7577<div class="doc_subsubsection">
7578 <a name="int_var_annotation">'<tt>llvm.var.annotation</tt>' Intrinsic</a>
7579</div>
7580
7581<div class="doc_text">
7582
7583<h5>Syntax:</h5>
7584<pre>
Tanya Lattnerbed1d4d2007-06-18 23:42:37 +0000[diff] [blame]7585 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]7586</pre>
7587
7588<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7589<p>The '<tt>llvm.var.annotation</tt>' intrinsic.</p>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]7590
7591<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7592<p>The first argument is a pointer to a value, the second is a pointer to a
7593 global string, the third is a pointer to a global string which is the source
7594 file name, and the last argument is the line number.</p>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]7595
7596<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7597<p>This intrinsic allows annotation of local variables with arbitrary strings.
7598 This can be useful for special purpose optimizations that want to look for
7599 these annotations. These have no other defined use, they are ignored by code
7600 generation and optimization.</p>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]7601
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]7602</div>
7603
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]7604<!-- _______________________________________________________________________ -->
7605<div class="doc_subsubsection">
Tanya Lattner0186a652007-09-21 23:57:59 +0000[diff] [blame]7606 <a name="int_annotation">'<tt>llvm.annotation.*</tt>' Intrinsic</a>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]7607</div>
7608
7609<div class="doc_text">
7610
7611<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7612<p>This is an overloaded intrinsic. You can use '<tt>llvm.annotation</tt>' on
7613 any integer bit width.</p>
7614
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]7615<pre>
Tanya Lattnercf3e26f2007-09-22 00:03:01 +0000[diff] [blame]7616 declare i8 @llvm.annotation.i8(i8 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7617 declare i16 @llvm.annotation.i16(i16 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7618 declare i32 @llvm.annotation.i32(i32 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7619 declare i64 @llvm.annotation.i64(i64 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7620 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]7621</pre>
7622
7623<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7624<p>The '<tt>llvm.annotation</tt>' intrinsic.</p>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]7625
7626<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7627<p>The first argument is an integer value (result of some expression), the
7628 second is a pointer to a global string, the third is a pointer to a global
7629 string which is the source file name, and the last argument is the line
7630 number. It returns the value of the first argument.</p>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]7631
7632<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7633<p>This intrinsic allows annotations to be put on arbitrary expressions with
7634 arbitrary strings. This can be useful for special purpose optimizations that
7635 want to look for these annotations. These have no other defined use, they
7636 are ignored by code generation and optimization.</p>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]7637
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]7638</div>
Jim Laskey2211f492007-03-14 19:31:19 +0000[diff] [blame]7639
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]7640<!-- _______________________________________________________________________ -->
7641<div class="doc_subsubsection">
7642 <a name="int_trap">'<tt>llvm.trap</tt>' Intrinsic</a>
7643</div>
7644
7645<div class="doc_text">
7646
7647<h5>Syntax:</h5>
7648<pre>
7649 declare void @llvm.trap()
7650</pre>
7651
7652<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7653<p>The '<tt>llvm.trap</tt>' intrinsic.</p>
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]7654
7655<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7656<p>None.</p>
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]7657
7658<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7659<p>This intrinsics is lowered to the target dependent trap instruction. If the
7660 target does not have a trap instruction, this intrinsic will be lowered to
7661 the call of the <tt>abort()</tt> function.</p>
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]7662
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]7663</div>
7664
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]7665<!-- _______________________________________________________________________ -->
7666<div class="doc_subsubsection">
Misha Brukman50de2b22008-11-22 23:55:29 +0000[diff] [blame]7667 <a name="int_stackprotector">'<tt>llvm.stackprotector</tt>' Intrinsic</a>
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]7668</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7669
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]7670<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7671
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]7672<h5>Syntax:</h5>
7673<pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7674 declare void @llvm.stackprotector( i8* &lt;guard&gt;, i8** &lt;slot&gt; )
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]7675</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7676
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]7677<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7678<p>The <tt>llvm.stackprotector</tt> intrinsic takes the <tt>guard</tt> and
7679 stores it onto the stack at <tt>slot</tt>. The stack slot is adjusted to
7680 ensure that it is placed on the stack before local variables.</p>
7681
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]7682<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7683<p>The <tt>llvm.stackprotector</tt> intrinsic requires two pointer
7684 arguments. The first argument is the value loaded from the stack
7685 guard <tt>@__stack_chk_guard</tt>. The second variable is an <tt>alloca</tt>
7686 that has enough space to hold the value of the guard.</p>
7687
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]7688<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7689<p>This intrinsic causes the prologue/epilogue inserter to force the position of
7690 the <tt>AllocaInst</tt> stack slot to be before local variables on the
7691 stack. This is to ensure that if a local variable on the stack is
7692 overwritten, it will destroy the value of the guard. When the function exits,
7693 the guard on the stack is checked against the original guard. If they're
7694 different, then the program aborts by calling the <tt>__stack_chk_fail()</tt>
7695 function.</p>
7696
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]7697</div>
7698
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]7699<!-- _______________________________________________________________________ -->
7700<div class="doc_subsubsection">
7701 <a name="int_objectsize">'<tt>llvm.objectsize</tt>' Intrinsic</a>
7702</div>
7703
7704<div class="doc_text">
7705
7706<h5>Syntax:</h5>
7707<pre>
Eric Christopher31e39bd2009-12-23 00:29:49 +0000[diff] [blame]7708 declare i32 @llvm.objectsize.i32( i8* &lt;object&gt;, i1 &lt;type&gt; )
7709 declare i64 @llvm.objectsize.i64( i8* &lt;object&gt;, i1 &lt;type&gt; )
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]7710</pre>
7711
7712<h5>Overview:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]7713<p>The <tt>llvm.objectsize</tt> intrinsic is designed to provide information
Eric Christopher3070e162010-01-08 21:42:39 +0000[diff] [blame]7714 to the optimizers to discover at compile time either a) when an
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]7715 operation like memcpy will either overflow a buffer that corresponds to
7716 an object, or b) to determine that a runtime check for overflow isn't
7717 necessary. An object in this context means an allocation of a
Eric Christopher31e39bd2009-12-23 00:29:49 +0000[diff] [blame]7718 specific class, structure, array, or other object.</p>
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]7719
7720<h5>Arguments:</h5>
7721<p>The <tt>llvm.objectsize</tt> intrinsic takes two arguments. The first
Eric Christopher31e39bd2009-12-23 00:29:49 +0000[diff] [blame]7722 argument is a pointer to or into the <tt>object</tt>. The second argument
7723 is a boolean 0 or 1. This argument determines whether you want the
7724 maximum (0) or minimum (1) bytes remaining. This needs to be a literal 0 or
7725 1, variables are not allowed.</p>
7726
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]7727<h5>Semantics:</h5>
7728<p>The <tt>llvm.objectsize</tt> intrinsic is lowered to either a constant
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]7729 representing the size of the object concerned or <tt>i32/i64 -1 or 0</tt>
7730 (depending on the <tt>type</tt> argument if the size cannot be determined
7731 at compile time.</p>
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]7732
7733</div>
7734
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]7735<!-- *********************************************************************** -->
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]7736<hr>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]7737<address>
7738 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
Misha Brukman86242e12008-12-11 17:34:48 +0000[diff] [blame]7739 src="http://jigsaw.w3.org/css-validator/images/vcss-blue" alt="Valid CSS"></a>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]7740 <a href="http://validator.w3.org/check/referer"><img
Misha Brukman86242e12008-12-11 17:34:48 +0000[diff] [blame]7741 src="http://www.w3.org/Icons/valid-html401-blue" alt="Valid HTML 4.01"></a>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]7742
7743 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
Reid Spencerca058542006-03-14 05:39:39 +0000[diff] [blame]7744 <a href="http://llvm.org">The LLVM Compiler Infrastructure</a><br>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]7745 Last modified: $Date$
7746</address>
Chris Lattnerb8f816e2008-01-04 04:33:49 +0000[diff] [blame]7747
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]7748</body>
7749</html>