Gitiles
Code Review Sign In
gerrit-public.fairphone.software / toolchain / llvm-project / e58f7b3c769942b1166408e509149ac754a055d4 / . / llvm / docs / LangRef.html
blob: 4b1919adf0348665b9d1067fd4db31afcaac3ec8 [file] [log] [blame]
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]1<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN"
2 "http://www.w3.org/TR/html4/strict.dtd">
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3<html>
4<head>
5 <title>LLVM Assembly Language Reference Manual</title>
Reid Spencercb84e432004-08-26 20:44:00 +0000[diff] [blame]6 <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
7 <meta name="author" content="Chris Lattner">
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]8 <meta name="description"
Reid Spencercb84e432004-08-26 20:44:00 +0000[diff] [blame]9 content="LLVM Assembly Language Reference Manual.">
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]10 <link rel="stylesheet" href="llvm.css" type="text/css">
11</head>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]12
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]13<body>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]14
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]15<div class="doc_title"> LLVM Language Reference Manual </div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]16<ol>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]17 <li><a href="#abstract">Abstract</a></li>
18 <li><a href="#introduction">Introduction</a></li>
19 <li><a href="#identifiers">Identifiers</a></li>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]20 <li><a href="#highlevel">High Level Structure</a>
21 <ol>
22 <li><a href="#modulestructure">Module Structure</a></li>
Bill Wendlinga3c6f6b2009-07-20 01:03:30 +0000[diff] [blame]23 <li><a href="#linkage">Linkage Types</a>
24 <ol>
Bill Wendling8693ef82009-07-20 02:41:50 +0000[diff] [blame]25 <li><a href="#linkage_private">'<tt>private</tt>' Linkage</a></li>
26 <li><a href="#linkage_linker_private">'<tt>linker_private</tt>' Linkage</a></li>
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>
Dan Gohmane58f7b32010-05-26 21:56:15 +0000[diff] [blame^]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 Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2339<p>There is currently no way of representing a trap value in the IR; they
Dan Gohmanac355aa2010-05-03 14:51:43 +0000[diff] [blame]2340 only exist when produced by operations such as
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2341 <a href="#i_add"><tt>add</tt></a> with the <tt>nsw</tt> flag.</p>
Dan Gohmanb8b85c12010-04-26 23:36:52 +0000[diff] [blame]2342
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2343<p>Trap value behavior is defined in terms of value <i>dependence</i>:</p>
Dan Gohmanb8b85c12010-04-26 23:36:52 +0000[diff] [blame]2344
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2345<p>
2346<ul>
2347<li>Values other than <a href="#i_phi"><tt>phi</tt></a> nodes depend on
2348 their operands.</li>
2349
2350<li><a href="#i_phi"><tt>Phi</tt></a> nodes depend on the operand corresponding
2351 to their dynamic predecessor basic block.</li>
2352
2353<li>Function arguments depend on the corresponding actual argument values in
2354 the dynamic callers of their functions.</li>
2355
2356<li><a href="#i_call"><tt>Call</tt></a> instructions depend on the
2357 <a href="#i_ret"><tt>ret</tt></a> instructions that dynamically transfer
2358 control back to them.</li>
2359
Dan Gohman7292a752010-05-03 14:55:22 +0000[diff] [blame]2360<li><a href="#i_invoke"><tt>Invoke</tt></a> instructions depend on the
2361 <a href="#i_ret"><tt>ret</tt></a>, <a href="#i_unwind"><tt>unwind</tt></a>,
2362 or exception-throwing call instructions that dynamically transfer control
2363 back to them.</li>
2364
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2365<li>Non-volatile loads and stores depend on the most recent stores to all of the
2366 referenced memory addresses, following the order in the IR
2367 (including loads and stores implied by intrinsics such as
2368 <a href="#int_memcpy"><tt>@llvm.memcpy</tt></a>.)</li>
2369
Dan Gohman3513ea52010-05-03 14:59:34 +0000[diff] [blame]2370<!-- TODO: In the case of multiple threads, this only applies if the store
2371 "happens-before" the load or store. -->
Dan Gohmanb8b85c12010-04-26 23:36:52 +0000[diff] [blame]2372
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2373<!-- TODO: floating-point exception state -->
Dan Gohmanb8b85c12010-04-26 23:36:52 +0000[diff] [blame]2374
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2375<li>An instruction with externally visible side effects depends on the most
2376 recent preceding instruction with externally visible side effects, following
2377 the order in the IR. (This includes volatile loads and stores.)</li>
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]2378
Dan Gohman7292a752010-05-03 14:55:22 +0000[diff] [blame]2379<li>An instruction <i>control-depends</i> on a
2380 <a href="#terminators">terminator instruction</a>
2381 if the terminator instruction has multiple successors and the instruction
2382 is always executed when control transfers to one of the successors, and
2383 may not be executed when control is transfered to another.</li>
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2384
2385<li>Dependence is transitive.</li>
2386
2387</ul>
2388</p>
2389
2390<p>Whenever a trap value is generated, all values which depend on it evaluate
2391 to trap. If they have side effects, the evoke their side effects as if each
2392 operand with a trap value were undef. If they have externally-visible side
2393 effects, the behavior is undefined.</p>
2394
2395<p>Here are some examples:</p>
Dan Gohman48a25882010-04-26 20:54:53 +0000[diff] [blame]2396
Dan Gohmanb8b85c12010-04-26 23:36:52 +0000[diff] [blame]2397<div class="doc_code">
2398<pre>
2399entry:
2400 %trap = sub nuw i32 0, 1 ; Results in a trap value.
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2401 %still_trap = and i32 %trap, 0 ; Whereas (and i32 undef, 0) would return 0.
2402 %trap_yet_again = getelementptr i32* @h, i32 %still_trap
2403 store i32 0, i32* %trap_yet_again ; undefined behavior
2404
2405 store i32 %trap, i32* @g ; Trap value conceptually stored to memory.
2406 %trap2 = load i32* @g ; Returns a trap value, not just undef.
2407
2408 volatile store i32 %trap, i32* @g ; External observation; undefined behavior.
2409
2410 %narrowaddr = bitcast i32* @g to i16*
2411 %wideaddr = bitcast i32* @g to i64*
2412 %trap3 = load 16* %narrowaddr ; Returns a trap value.
2413 %trap4 = load i64* %widaddr ; Returns a trap value.
2414
2415 %cmp = icmp i32 slt %trap, 0 ; Returns a trap value.
Dan Gohmanb8b85c12010-04-26 23:36:52 +0000[diff] [blame]2416 %br i1 %cmp, %true, %end ; Branch to either destination.
2417
2418true:
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2419 volatile store i32 0, i32* @g ; This is control-dependent on %cmp, so
2420 ; it has undefined behavior.
Dan Gohmanb8b85c12010-04-26 23:36:52 +0000[diff] [blame]2421 br label %end
2422
2423end:
2424 %p = phi i32 [ 0, %entry ], [ 1, %true ]
2425 ; Both edges into this PHI are
2426 ; control-dependent on %cmp, so this
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2427 ; always results in a trap value.
Dan Gohmanb8b85c12010-04-26 23:36:52 +0000[diff] [blame]2428
2429 volatile store i32 0, i32* @g ; %end is control-equivalent to %entry
2430 ; so this is defined (ignoring earlier
2431 ; undefined behavior in this example).
Dan Gohmanb8b85c12010-04-26 23:36:52 +0000[diff] [blame]2432</pre>
2433</div>
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]2434
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]2435</div>
2436
2437<!-- ======================================================================= -->
Chris Lattner2bfd3202009-10-27 21:19:13 +0000[diff] [blame]2438<div class="doc_subsection"><a name="blockaddress">Addresses of Basic
2439 Blocks</a></div>
Chris Lattnere4801f72009-10-27 21:01:34 +0000[diff] [blame]2440<div class="doc_text">
2441
Chris Lattneraa99c942009-11-01 01:27:45 +0000[diff] [blame]2442<p><b><tt>blockaddress(@function, %block)</tt></b></p>
Chris Lattnere4801f72009-10-27 21:01:34 +0000[diff] [blame]2443
2444<p>The '<tt>blockaddress</tt>' constant computes the address of the specified
Chris Lattner5c5f0ac2009-10-27 21:49:40 +0000[diff] [blame]2445 basic block in the specified function, and always has an i8* type. Taking
Chris Lattneraa99c942009-11-01 01:27:45 +0000[diff] [blame]2446 the address of the entry block is illegal.</p>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]2447
Chris Lattnere4801f72009-10-27 21:01:34 +0000[diff] [blame]2448<p>This value only has defined behavior when used as an operand to the
Chris Lattnerd04cb6d2009-10-28 00:19:10 +0000[diff] [blame]2449 '<a href="#i_indirectbr"><tt>indirectbr</tt></a>' instruction or for comparisons
Chris Lattnere4801f72009-10-27 21:01:34 +0000[diff] [blame]2450 against null. Pointer equality tests between labels addresses is undefined
2451 behavior - though, again, comparison against null is ok, and no label is
Chris Lattner2bfd3202009-10-27 21:19:13 +0000[diff] [blame]2452 equal to the null pointer. This may also be passed around as an opaque
2453 pointer sized value as long as the bits are not inspected. This allows
Chris Lattnerda37b302009-10-27 21:44:20 +0000[diff] [blame]2454 <tt>ptrtoint</tt> and arithmetic to be performed on these values so long as
Chris Lattnerd04cb6d2009-10-28 00:19:10 +0000[diff] [blame]2455 the original value is reconstituted before the <tt>indirectbr</tt>.</p>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]2456
Chris Lattner2bfd3202009-10-27 21:19:13 +0000[diff] [blame]2457<p>Finally, some targets may provide defined semantics when
Chris Lattnere4801f72009-10-27 21:01:34 +0000[diff] [blame]2458 using the value as the operand to an inline assembly, but that is target
2459 specific.
2460 </p>
2461
2462</div>
2463
2464
2465<!-- ======================================================================= -->
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2466<div class="doc_subsection"><a name="constantexprs">Constant Expressions</a>
2467</div>
2468
2469<div class="doc_text">
2470
2471<p>Constant expressions are used to allow expressions involving other constants
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2472 to be used as constants. Constant expressions may be of
2473 any <a href="#t_firstclass">first class</a> type and may involve any LLVM
2474 operation that does not have side effects (e.g. load and call are not
2475 supported). The following is the syntax for constant expressions:</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2476
2477<dl>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2478 <dt><b><tt>trunc ( CST to TYPE )</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2479 <dd>Truncate a constant to another type. The bit size of CST must be larger
2480 than the bit size of TYPE. Both types must be integers.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2481
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2482 <dt><b><tt>zext ( CST to TYPE )</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2483 <dd>Zero extend a constant to another type. The bit size of CST must be
2484 smaller or equal to the bit size of TYPE. Both types must be
2485 integers.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2486
2487 <dt><b><tt>sext ( CST to TYPE )</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2488 <dd>Sign extend a constant to another type. The bit size of CST must be
2489 smaller or equal to the bit size of TYPE. Both types must be
2490 integers.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2491
2492 <dt><b><tt>fptrunc ( CST to TYPE )</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2493 <dd>Truncate a floating point constant to another floating point type. The
2494 size of CST must be larger than the size of TYPE. Both types must be
2495 floating point.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2496
2497 <dt><b><tt>fpext ( CST to TYPE )</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2498 <dd>Floating point extend a constant to another type. The size of CST must be
2499 smaller or equal to the size of TYPE. Both types must be floating
2500 point.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2501
Reid Spencer753163d2007-07-31 14:40:14 +0000[diff] [blame]2502 <dt><b><tt>fptoui ( CST to TYPE )</tt></b></dt>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2503 <dd>Convert a floating point constant to the corresponding unsigned integer
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2504 constant. TYPE must be a scalar or vector integer type. CST must be of
2505 scalar or vector floating point type. Both CST and TYPE must be scalars,
2506 or vectors of the same number of elements. If the value won't fit in the
2507 integer type, the results are undefined.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2508
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]2509 <dt><b><tt>fptosi ( CST to TYPE )</tt></b></dt>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2510 <dd>Convert a floating point constant to the corresponding signed integer
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2511 constant. TYPE must be a scalar or vector integer type. CST must be of
2512 scalar or vector floating point type. Both CST and TYPE must be scalars,
2513 or vectors of the same number of elements. If the value won't fit in the
2514 integer type, the results are undefined.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2515
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]2516 <dt><b><tt>uitofp ( CST to TYPE )</tt></b></dt>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2517 <dd>Convert an unsigned integer constant to the corresponding floating point
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2518 constant. TYPE must be a scalar or vector floating point type. CST must be
2519 of scalar or vector integer type. Both CST and TYPE must be scalars, or
2520 vectors of the same number of elements. If the value won't fit in the
2521 floating point type, the results are undefined.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2522
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]2523 <dt><b><tt>sitofp ( CST to TYPE )</tt></b></dt>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2524 <dd>Convert a signed integer constant to the corresponding floating point
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2525 constant. TYPE must be a scalar or vector floating point type. CST must be
2526 of scalar or vector integer type. Both CST and TYPE must be scalars, or
2527 vectors of the same number of elements. If the value won't fit in the
2528 floating point type, the results are undefined.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2529
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]2530 <dt><b><tt>ptrtoint ( CST to TYPE )</tt></b></dt>
2531 <dd>Convert a pointer typed constant to the corresponding integer constant
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2532 <tt>TYPE</tt> must be an integer type. <tt>CST</tt> must be of pointer
2533 type. The <tt>CST</tt> value is zero extended, truncated, or unchanged to
2534 make it fit in <tt>TYPE</tt>.</dd>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]2535
2536 <dt><b><tt>inttoptr ( CST to TYPE )</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2537 <dd>Convert a integer constant to a pointer constant. TYPE must be a pointer
2538 type. CST must be of integer type. The CST value is zero extended,
2539 truncated, or unchanged to make it fit in a pointer size. This one is
2540 <i>really</i> dangerous!</dd>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]2541
2542 <dt><b><tt>bitcast ( CST to TYPE )</tt></b></dt>
Chris Lattner789dee32009-02-28 18:27:03 +0000[diff] [blame]2543 <dd>Convert a constant, CST, to another TYPE. The constraints of the operands
2544 are the same as those for the <a href="#i_bitcast">bitcast
2545 instruction</a>.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2546
2547 <dt><b><tt>getelementptr ( CSTPTR, IDX0, IDX1, ... )</tt></b></dt>
Dan Gohman1639c392009-07-27 21:53:46 +0000[diff] [blame]2548 <dt><b><tt>getelementptr inbounds ( CSTPTR, IDX0, IDX1, ... )</tt></b></dt>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2549 <dd>Perform the <a href="#i_getelementptr">getelementptr operation</a> on
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2550 constants. As with the <a href="#i_getelementptr">getelementptr</a>
2551 instruction, the index list may have zero or more indexes, which are
2552 required to make sense for the type of "CSTPTR".</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2553
Robert Bocchino7e97a6d2006-01-10 19:31:34 +0000[diff] [blame]2554 <dt><b><tt>select ( COND, VAL1, VAL2 )</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2555 <dd>Perform the <a href="#i_select">select operation</a> on constants.</dd>
Reid Spencer9965ee72006-12-04 19:23:19 +0000[diff] [blame]2556
2557 <dt><b><tt>icmp COND ( VAL1, VAL2 )</tt></b></dt>
2558 <dd>Performs the <a href="#i_icmp">icmp operation</a> on constants.</dd>
2559
2560 <dt><b><tt>fcmp COND ( VAL1, VAL2 )</tt></b></dt>
2561 <dd>Performs the <a href="#i_fcmp">fcmp operation</a> on constants.</dd>
Robert Bocchino7e97a6d2006-01-10 19:31:34 +0000[diff] [blame]2562
2563 <dt><b><tt>extractelement ( VAL, IDX )</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2564 <dd>Perform the <a href="#i_extractelement">extractelement operation</a> on
2565 constants.</dd>
Robert Bocchino7e97a6d2006-01-10 19:31:34 +0000[diff] [blame]2566
Robert Bocchinof72fdfe2006-01-15 20:48:27 +0000[diff] [blame]2567 <dt><b><tt>insertelement ( VAL, ELT, IDX )</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2568 <dd>Perform the <a href="#i_insertelement">insertelement operation</a> on
2569 constants.</dd>
Chris Lattner016a0e52006-04-08 00:13:41 +0000[diff] [blame]2570
2571 <dt><b><tt>shufflevector ( VEC1, VEC2, IDXMASK )</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2572 <dd>Perform the <a href="#i_shufflevector">shufflevector operation</a> on
2573 constants.</dd>
Chris Lattner016a0e52006-04-08 00:13:41 +0000[diff] [blame]2574
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2575 <dt><b><tt>OPCODE ( LHS, RHS )</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2576 <dd>Perform the specified operation of the LHS and RHS constants. OPCODE may
2577 be any of the <a href="#binaryops">binary</a>
2578 or <a href="#bitwiseops">bitwise binary</a> operations. The constraints
2579 on operands are the same as those for the corresponding instruction
2580 (e.g. no bitwise operations on floating point values are allowed).</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2581</dl>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2582
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2583</div>
Chris Lattnerb1652612004-03-08 16:49:10 +0000[diff] [blame]2584
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2585<!-- *********************************************************************** -->
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2586<div class="doc_section"> <a name="othervalues">Other Values</a> </div>
2587<!-- *********************************************************************** -->
2588
2589<!-- ======================================================================= -->
2590<div class="doc_subsection">
2591<a name="inlineasm">Inline Assembler Expressions</a>
2592</div>
2593
2594<div class="doc_text">
2595
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2596<p>LLVM supports inline assembler expressions (as opposed
2597 to <a href="#moduleasm"> Module-Level Inline Assembly</a>) through the use of
2598 a special value. This value represents the inline assembler as a string
2599 (containing the instructions to emit), a list of operand constraints (stored
Dale Johannesen63c94fe2009-10-13 21:56:55 +0000[diff] [blame]2600 as a string), a flag that indicates whether or not the inline asm
Dale Johannesen1cfb9582009-10-21 23:28:00 +0000[diff] [blame]2601 expression has side effects, and a flag indicating whether the function
2602 containing the asm needs to align its stack conservatively. An example
2603 inline assembler expression is:</p>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2604
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2605<div class="doc_code">
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2606<pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2607i32 (i32) asm "bswap $0", "=r,r"
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2608</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2609</div>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2610
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2611<p>Inline assembler expressions may <b>only</b> be used as the callee operand of
2612 a <a href="#i_call"><tt>call</tt> instruction</a>. Thus, typically we
2613 have:</p>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2614
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2615<div class="doc_code">
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2616<pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2617%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]2618</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2619</div>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2620
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2621<p>Inline asms with side effects not visible in the constraint list must be
2622 marked as having side effects. This is done through the use of the
2623 '<tt>sideeffect</tt>' keyword, like so:</p>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2624
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2625<div class="doc_code">
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2626<pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2627call void asm sideeffect "eieio", ""()
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2628</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2629</div>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2630
Dale Johannesen1cfb9582009-10-21 23:28:00 +0000[diff] [blame]2631<p>In some cases inline asms will contain code that will not work unless the
2632 stack is aligned in some way, such as calls or SSE instructions on x86,
2633 yet will not contain code that does that alignment within the asm.
2634 The compiler should make conservative assumptions about what the asm might
2635 contain and should generate its usual stack alignment code in the prologue
2636 if the '<tt>alignstack</tt>' keyword is present:</p>
Dale Johannesen63c94fe2009-10-13 21:56:55 +0000[diff] [blame]2637
2638<div class="doc_code">
2639<pre>
Dale Johannesen1cfb9582009-10-21 23:28:00 +0000[diff] [blame]2640call void asm alignstack "eieio", ""()
Dale Johannesen63c94fe2009-10-13 21:56:55 +0000[diff] [blame]2641</pre>
2642</div>
2643
2644<p>If both keywords appear the '<tt>sideeffect</tt>' keyword must come
2645 first.</p>
2646
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2647<p>TODO: The format of the asm and constraints string still need to be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2648 documented here. Constraints on what can be done (e.g. duplication, moving,
2649 etc need to be documented). This is probably best done by reference to
2650 another document that covers inline asm from a holistic perspective.</p>
Chris Lattner51065562010-04-07 05:38:05 +0000[diff] [blame]2651</div>
2652
2653<div class="doc_subsubsection">
2654<a name="inlineasm_md">Inline Asm Metadata</a>
2655</div>
2656
2657<div class="doc_text">
2658
2659<p>The call instructions that wrap inline asm nodes may have a "!srcloc" MDNode
2660 attached to it that contains a constant integer. If present, the code
2661 generator will use the integer as the location cookie value when report
2662 errors through the LLVMContext error reporting mechanisms. This allows a
Dan Gohman61110ae2010-04-28 00:36:01 +0000[diff] [blame]2663 front-end to correlate backend errors that occur with inline asm back to the
Chris Lattner51065562010-04-07 05:38:05 +0000[diff] [blame]2664 source code that produced it. For example:</p>
2665
2666<div class="doc_code">
2667<pre>
2668call void asm sideeffect "something bad", ""()<b>, !srcloc !42</b>
2669...
2670!42 = !{ i32 1234567 }
2671</pre>
2672</div>
2673
2674<p>It is up to the front-end to make sense of the magic numbers it places in the
2675 IR.</p>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2676
2677</div>
2678
Chris Lattnerc2f8f162010-01-15 21:50:19 +0000[diff] [blame]2679<!-- ======================================================================= -->
2680<div class="doc_subsection"><a name="metadata">Metadata Nodes and Metadata
2681 Strings</a>
2682</div>
2683
2684<div class="doc_text">
2685
2686<p>LLVM IR allows metadata to be attached to instructions in the program that
2687 can convey extra information about the code to the optimizers and code
2688 generator. One example application of metadata is source-level debug
2689 information. There are two metadata primitives: strings and nodes. All
2690 metadata has the <tt>metadata</tt> type and is identified in syntax by a
2691 preceding exclamation point ('<tt>!</tt>').</p>
2692
2693<p>A metadata string is a string surrounded by double quotes. It can contain
2694 any character by escaping non-printable characters with "\xx" where "xx" is
2695 the two digit hex code. For example: "<tt>!"test\00"</tt>".</p>
2696
2697<p>Metadata nodes are represented with notation similar to structure constants
2698 (a comma separated list of elements, surrounded by braces and preceded by an
2699 exclamation point). For example: "<tt>!{ metadata !"test\00", i32
2700 10}</tt>". Metadata nodes can have any values as their operand.</p>
2701
2702<p>A <a href="#namedmetadatastructure">named metadata</a> is a collection of
2703 metadata nodes, which can be looked up in the module symbol table. For
2704 example: "<tt>!foo = metadata !{!4, !3}</tt>".
2705
Devang Patel9984bd62010-03-04 23:44:48 +0000[diff] [blame]2706<p>Metadata can be used as function arguments. Here <tt>llvm.dbg.value</tt>
2707 function is using two metadata arguments.
2708
2709 <div class="doc_code">
2710 <pre>
2711 call void @llvm.dbg.value(metadata !24, i64 0, metadata !25)
2712 </pre>
2713 </div></p>
2714
2715<p>Metadata can be attached with an instruction. Here metadata <tt>!21</tt> is
2716 attached with <tt>add</tt> instruction using <tt>!dbg</tt> identifier.
2717
2718 <div class="doc_code">
2719 <pre>
2720 %indvar.next = add i64 %indvar, 1, !dbg !21
2721 </pre>
2722 </div></p>
Chris Lattnerc2f8f162010-01-15 21:50:19 +0000[diff] [blame]2723</div>
2724
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]2725
2726<!-- *********************************************************************** -->
2727<div class="doc_section">
2728 <a name="intrinsic_globals">Intrinsic Global Variables</a>
2729</div>
2730<!-- *********************************************************************** -->
2731
2732<p>LLVM has a number of "magic" global variables that contain data that affect
2733code generation or other IR semantics. These are documented here. All globals
Chris Lattner58f9bb22009-07-20 06:14:25 +0000[diff] [blame]2734of this sort should have a section specified as "<tt>llvm.metadata</tt>". This
2735section and all globals that start with "<tt>llvm.</tt>" are reserved for use
2736by LLVM.</p>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]2737
2738<!-- ======================================================================= -->
2739<div class="doc_subsection">
2740<a name="intg_used">The '<tt>llvm.used</tt>' Global Variable</a>
2741</div>
2742
2743<div class="doc_text">
2744
2745<p>The <tt>@llvm.used</tt> global is an array with i8* element type which has <a
2746href="#linkage_appending">appending linkage</a>. This array contains a list of
2747pointers to global variables and functions which may optionally have a pointer
2748cast formed of bitcast or getelementptr. For example, a legal use of it is:</p>
2749
2750<pre>
2751 @X = global i8 4
2752 @Y = global i32 123
2753
2754 @llvm.used = appending global [2 x i8*] [
2755 i8* @X,
2756 i8* bitcast (i32* @Y to i8*)
2757 ], section "llvm.metadata"
2758</pre>
2759
2760<p>If a global variable appears in the <tt>@llvm.used</tt> list, then the
2761compiler, assembler, and linker are required to treat the symbol as if there is
2762a reference to the global that it cannot see. For example, if a variable has
2763internal linkage and no references other than that from the <tt>@llvm.used</tt>
2764list, it cannot be deleted. This is commonly used to represent references from
2765inline asms and other things the compiler cannot "see", and corresponds to
2766"attribute((used))" in GNU C.</p>
2767
2768<p>On some targets, the code generator must emit a directive to the assembler or
2769object file to prevent the assembler and linker from molesting the symbol.</p>
2770
2771</div>
2772
2773<!-- ======================================================================= -->
2774<div class="doc_subsection">
Chris Lattner58f9bb22009-07-20 06:14:25 +0000[diff] [blame]2775<a name="intg_compiler_used">The '<tt>llvm.compiler.used</tt>' Global Variable</a>
2776</div>
2777
2778<div class="doc_text">
2779
2780<p>The <tt>@llvm.compiler.used</tt> directive is the same as the
2781<tt>@llvm.used</tt> directive, except that it only prevents the compiler from
2782touching the symbol. On targets that support it, this allows an intelligent
2783linker to optimize references to the symbol without being impeded as it would be
2784by <tt>@llvm.used</tt>.</p>
2785
2786<p>This is a rare construct that should only be used in rare circumstances, and
2787should not be exposed to source languages.</p>
2788
2789</div>
2790
2791<!-- ======================================================================= -->
2792<div class="doc_subsection">
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]2793<a name="intg_global_ctors">The '<tt>llvm.global_ctors</tt>' Global Variable</a>
2794</div>
2795
2796<div class="doc_text">
David Chisnalla9d4a6f2010-04-30 19:23:49 +0000[diff] [blame]2797<pre>
2798%0 = type { i32, void ()* }
David Chisnallb492b812010-04-30 19:27:35 +0000[diff] [blame]2799@llvm.global_ctors = appending global [1 x %0] [%0 { i32 65535, void ()* @ctor }]
David Chisnalla9d4a6f2010-04-30 19:23:49 +0000[diff] [blame]2800</pre>
2801<p>The <tt>@llvm.global_ctors</tt> array contains a list of constructor functions and associated priorities. The functions referenced by this array will be called in ascending order of priority (i.e. lowest first) when the module is loaded. The order of functions with the same priority is not defined.
2802</p>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]2803
2804</div>
2805
2806<!-- ======================================================================= -->
2807<div class="doc_subsection">
2808<a name="intg_global_dtors">The '<tt>llvm.global_dtors</tt>' Global Variable</a>
2809</div>
2810
2811<div class="doc_text">
David Chisnalla9d4a6f2010-04-30 19:23:49 +0000[diff] [blame]2812<pre>
2813%0 = type { i32, void ()* }
David Chisnallb492b812010-04-30 19:27:35 +0000[diff] [blame]2814@llvm.global_dtors = appending global [1 x %0] [%0 { i32 65535, void ()* @dtor }]
David Chisnalla9d4a6f2010-04-30 19:23:49 +0000[diff] [blame]2815</pre>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]2816
David Chisnalla9d4a6f2010-04-30 19:23:49 +0000[diff] [blame]2817<p>The <tt>@llvm.global_dtors</tt> array contains a list of destructor functions and associated priorities. The functions referenced by this array will be called in descending order of priority (i.e. highest first) when the module is loaded. The order of functions with the same priority is not defined.
2818</p>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]2819
2820</div>
2821
2822
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2823<!-- *********************************************************************** -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2824<div class="doc_section"> <a name="instref">Instruction Reference</a> </div>
2825<!-- *********************************************************************** -->
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2826
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2827<div class="doc_text">
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2828
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2829<p>The LLVM instruction set consists of several different classifications of
2830 instructions: <a href="#terminators">terminator
2831 instructions</a>, <a href="#binaryops">binary instructions</a>,
2832 <a href="#bitwiseops">bitwise binary instructions</a>,
2833 <a href="#memoryops">memory instructions</a>, and
2834 <a href="#otherops">other instructions</a>.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2835
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2836</div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2837
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2838<!-- ======================================================================= -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2839<div class="doc_subsection"> <a name="terminators">Terminator
2840Instructions</a> </div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2841
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2842<div class="doc_text">
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2843
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2844<p>As mentioned <a href="#functionstructure">previously</a>, every basic block
2845 in a program ends with a "Terminator" instruction, which indicates which
2846 block should be executed after the current block is finished. These
2847 terminator instructions typically yield a '<tt>void</tt>' value: they produce
2848 control flow, not values (the one exception being the
2849 '<a href="#i_invoke"><tt>invoke</tt></a>' instruction).</p>
2850
Duncan Sands626b0242010-04-15 20:35:54 +0000[diff] [blame]2851<p>There are seven different terminator instructions: the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2852 '<a href="#i_ret"><tt>ret</tt></a>' instruction, the
2853 '<a href="#i_br"><tt>br</tt></a>' instruction, the
2854 '<a href="#i_switch"><tt>switch</tt></a>' instruction, the
Bill Wendling33fef7e2009-11-02 00:25:26 +0000[diff] [blame]2855 '<a href="#i_indirectbr">'<tt>indirectbr</tt></a>' Instruction, the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2856 '<a href="#i_invoke"><tt>invoke</tt></a>' instruction, the
2857 '<a href="#i_unwind"><tt>unwind</tt></a>' instruction, and the
2858 '<a href="#i_unreachable"><tt>unreachable</tt></a>' instruction.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2859
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2860</div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2861
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2862<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2863<div class="doc_subsubsection"> <a name="i_ret">'<tt>ret</tt>'
2864Instruction</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2865
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2866<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2867
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2868<h5>Syntax:</h5>
Dan Gohmancc3132e2008-10-04 19:00:07 +0000[diff] [blame]2869<pre>
2870 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]2871 ret void <i>; Return from void function</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2872</pre>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]2873
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2874<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2875<p>The '<tt>ret</tt>' instruction is used to return control flow (and optionally
2876 a value) from a function back to the caller.</p>
2877
2878<p>There are two forms of the '<tt>ret</tt>' instruction: one that returns a
2879 value and then causes control flow, and one that just causes control flow to
2880 occur.</p>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]2881
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2882<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2883<p>The '<tt>ret</tt>' instruction optionally accepts a single argument, the
2884 return value. The type of the return value must be a
2885 '<a href="#t_firstclass">first class</a>' type.</p>
Dan Gohmancc3132e2008-10-04 19:00:07 +0000[diff] [blame]2886
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2887<p>A function is not <a href="#wellformed">well formed</a> if it it has a
2888 non-void return type and contains a '<tt>ret</tt>' instruction with no return
2889 value or a return value with a type that does not match its type, or if it
2890 has a void return type and contains a '<tt>ret</tt>' instruction with a
2891 return value.</p>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]2892
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2893<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2894<p>When the '<tt>ret</tt>' instruction is executed, control flow returns back to
2895 the calling function's context. If the caller is a
2896 "<a href="#i_call"><tt>call</tt></a>" instruction, execution continues at the
2897 instruction after the call. If the caller was an
2898 "<a href="#i_invoke"><tt>invoke</tt></a>" instruction, execution continues at
2899 the beginning of the "normal" destination block. If the instruction returns
2900 a value, that value shall set the call or invoke instruction's return
2901 value.</p>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]2902
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2903<h5>Example:</h5>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]2904<pre>
2905 ret i32 5 <i>; Return an integer value of 5</i>
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]2906 ret void <i>; Return from a void function</i>
Bill Wendling050ee8f2009-02-28 22:12:54 +0000[diff] [blame]2907 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]2908</pre>
Dan Gohman3065b612009-01-12 23:12:39 +0000[diff] [blame]2909
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2910</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2911<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2912<div class="doc_subsubsection"> <a name="i_br">'<tt>br</tt>' Instruction</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2913
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2914<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2915
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2916<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2917<pre>
2918 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]2919</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2920
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2921<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2922<p>The '<tt>br</tt>' instruction is used to cause control flow to transfer to a
2923 different basic block in the current function. There are two forms of this
2924 instruction, corresponding to a conditional branch and an unconditional
2925 branch.</p>
2926
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2927<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2928<p>The conditional branch form of the '<tt>br</tt>' instruction takes a single
2929 '<tt>i1</tt>' value and two '<tt>label</tt>' values. The unconditional form
2930 of the '<tt>br</tt>' instruction takes a single '<tt>label</tt>' value as a
2931 target.</p>
2932
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2933<h5>Semantics:</h5>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]2934<p>Upon execution of a conditional '<tt>br</tt>' instruction, the '<tt>i1</tt>'
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2935 argument is evaluated. If the value is <tt>true</tt>, control flows to the
2936 '<tt>iftrue</tt>' <tt>label</tt> argument. If "cond" is <tt>false</tt>,
2937 control flows to the '<tt>iffalse</tt>' <tt>label</tt> argument.</p>
2938
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2939<h5>Example:</h5>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]2940<pre>
2941Test:
2942 %cond = <a href="#i_icmp">icmp</a> eq i32 %a, %b
2943 br i1 %cond, label %IfEqual, label %IfUnequal
2944IfEqual:
2945 <a href="#i_ret">ret</a> i32 1
2946IfUnequal:
2947 <a href="#i_ret">ret</a> i32 0
2948</pre>
2949
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2950</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2951
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2952<!-- _______________________________________________________________________ -->
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2953<div class="doc_subsubsection">
2954 <a name="i_switch">'<tt>switch</tt>' Instruction</a>
2955</div>
2956
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2957<div class="doc_text">
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2958
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2959<h5>Syntax:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2960<pre>
2961 switch &lt;intty&gt; &lt;value&gt;, label &lt;defaultdest&gt; [ &lt;intty&gt; &lt;val&gt;, label &lt;dest&gt; ... ]
2962</pre>
2963
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2964<h5>Overview:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2965<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]2966 several different places. It is a generalization of the '<tt>br</tt>'
2967 instruction, allowing a branch to occur to one of many possible
2968 destinations.</p>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2969
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2970<h5>Arguments:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2971<p>The '<tt>switch</tt>' instruction uses three parameters: an integer
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2972 comparison value '<tt>value</tt>', a default '<tt>label</tt>' destination,
2973 and an array of pairs of comparison value constants and '<tt>label</tt>'s.
2974 The table is not allowed to contain duplicate constant entries.</p>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2975
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2976<h5>Semantics:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2977<p>The <tt>switch</tt> instruction specifies a table of values and
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2978 destinations. When the '<tt>switch</tt>' instruction is executed, this table
2979 is searched for the given value. If the value is found, control flow is
Benjamin Kramer0f420382009-10-12 14:46:08 +0000[diff] [blame]2980 transferred to the corresponding destination; otherwise, control flow is
2981 transferred to the default destination.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2982
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2983<h5>Implementation:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2984<p>Depending on properties of the target machine and the particular
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2985 <tt>switch</tt> instruction, this instruction may be code generated in
2986 different ways. For example, it could be generated as a series of chained
2987 conditional branches or with a lookup table.</p>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2988
2989<h5>Example:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2990<pre>
2991 <i>; Emulate a conditional br instruction</i>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]2992 %Val = <a href="#i_zext">zext</a> i1 %value to i32
Dan Gohman623806e2009-01-04 23:44:43 +0000[diff] [blame]2993 switch i32 %Val, label %truedest [ i32 0, label %falsedest ]
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2994
2995 <i>; Emulate an unconditional br instruction</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2996 switch i32 0, label %dest [ ]
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2997
2998 <i>; Implement a jump table:</i>
Dan Gohman623806e2009-01-04 23:44:43 +0000[diff] [blame]2999 switch i32 %val, label %otherwise [ i32 0, label %onzero
3000 i32 1, label %onone
3001 i32 2, label %ontwo ]
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3002</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3003
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3004</div>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3005
Chris Lattner3ed871f2009-10-27 19:13:16 +0000[diff] [blame]3006
3007<!-- _______________________________________________________________________ -->
3008<div class="doc_subsubsection">
Chris Lattnerd04cb6d2009-10-28 00:19:10 +0000[diff] [blame]3009 <a name="i_indirectbr">'<tt>indirectbr</tt>' Instruction</a>
Chris Lattner3ed871f2009-10-27 19:13:16 +0000[diff] [blame]3010</div>
3011
3012<div class="doc_text">
3013
3014<h5>Syntax:</h5>
3015<pre>
Chris Lattnerd04cb6d2009-10-28 00:19:10 +0000[diff] [blame]3016 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]3017</pre>
3018
3019<h5>Overview:</h5>
3020
Chris Lattnerd04cb6d2009-10-28 00:19:10 +0000[diff] [blame]3021<p>The '<tt>indirectbr</tt>' instruction implements an indirect branch to a label
Chris Lattner3ed871f2009-10-27 19:13:16 +0000[diff] [blame]3022 within the current function, whose address is specified by
Chris Lattnere4801f72009-10-27 21:01:34 +0000[diff] [blame]3023 "<tt>address</tt>". Address must be derived from a <a
3024 href="#blockaddress">blockaddress</a> constant.</p>
Chris Lattner3ed871f2009-10-27 19:13:16 +0000[diff] [blame]3025
3026<h5>Arguments:</h5>
3027
3028<p>The '<tt>address</tt>' argument is the address of the label to jump to. The
3029 rest of the arguments indicate the full set of possible destinations that the
3030 address may point to. Blocks are allowed to occur multiple times in the
3031 destination list, though this isn't particularly useful.</p>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3032
Chris Lattner3ed871f2009-10-27 19:13:16 +0000[diff] [blame]3033<p>This destination list is required so that dataflow analysis has an accurate
3034 understanding of the CFG.</p>
3035
3036<h5>Semantics:</h5>
3037
3038<p>Control transfers to the block specified in the address argument. All
3039 possible destination blocks must be listed in the label list, otherwise this
3040 instruction has undefined behavior. This implies that jumps to labels
3041 defined in other functions have undefined behavior as well.</p>
3042
3043<h5>Implementation:</h5>
3044
3045<p>This is typically implemented with a jump through a register.</p>
3046
3047<h5>Example:</h5>
3048<pre>
Chris Lattnerd04cb6d2009-10-28 00:19:10 +0000[diff] [blame]3049 indirectbr i8* %Addr, [ label %bb1, label %bb2, label %bb3 ]
Chris Lattner3ed871f2009-10-27 19:13:16 +0000[diff] [blame]3050</pre>
3051
3052</div>
3053
3054
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3055<!-- _______________________________________________________________________ -->
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3056<div class="doc_subsubsection">
3057 <a name="i_invoke">'<tt>invoke</tt>' Instruction</a>
3058</div>
3059
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3060<div class="doc_text">
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3061
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3062<h5>Syntax:</h5>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3063<pre>
Devang Patel02256232008-10-07 17:48:33 +0000[diff] [blame]3064 &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]3065 to label &lt;normal label&gt; unwind label &lt;exception label&gt;
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3066</pre>
3067
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]3068<h5>Overview:</h5>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3069<p>The '<tt>invoke</tt>' instruction causes control to transfer to a specified
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3070 function, with the possibility of control flow transfer to either the
3071 '<tt>normal</tt>' label or the '<tt>exception</tt>' label. If the callee
3072 function returns with the "<tt><a href="#i_ret">ret</a></tt>" instruction,
3073 control flow will return to the "normal" label. If the callee (or any
3074 indirect callees) returns with the "<a href="#i_unwind"><tt>unwind</tt></a>"
3075 instruction, control is interrupted and continued at the dynamically nearest
3076 "exception" label.</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3077
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3078<h5>Arguments:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3079<p>This instruction requires several arguments:</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3080
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3081<ol>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3082 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
3083 convention</a> the call should use. If none is specified, the call
3084 defaults to using C calling conventions.</li>
Devang Patel7e9b05e2008-10-06 18:50:38 +0000[diff] [blame]3085
3086 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3087 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
3088 '<tt>inreg</tt>' attributes are valid here.</li>
Devang Patel7e9b05e2008-10-06 18:50:38 +0000[diff] [blame]3089
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3090 <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]3091 function value being invoked. In most cases, this is a direct function
3092 invocation, but indirect <tt>invoke</tt>s are just as possible, branching
3093 off an arbitrary pointer to function value.</li>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3094
3095 <li>'<tt>function ptr val</tt>': An LLVM value containing a pointer to a
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3096 function to be invoked. </li>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3097
3098 <li>'<tt>function args</tt>': argument list whose types match the function
Chris Lattner47f2a832010-03-02 06:36:51 +0000[diff] [blame]3099 signature argument types and parameter attributes. All arguments must be
3100 of <a href="#t_firstclass">first class</a> type. If the function
3101 signature indicates the function accepts a variable number of arguments,
3102 the extra arguments can be specified.</li>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3103
3104 <li>'<tt>normal label</tt>': the label reached when the called function
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3105 executes a '<tt><a href="#i_ret">ret</a></tt>' instruction. </li>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3106
3107 <li>'<tt>exception label</tt>': the label reached when a callee returns with
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3108 the <a href="#i_unwind"><tt>unwind</tt></a> instruction. </li>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3109
Devang Patel02256232008-10-07 17:48:33 +0000[diff] [blame]3110 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3111 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
3112 '<tt>readnone</tt>' attributes are valid here.</li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3113</ol>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3114
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3115<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3116<p>This instruction is designed to operate as a standard
3117 '<tt><a href="#i_call">call</a></tt>' instruction in most regards. The
3118 primary difference is that it establishes an association with a label, which
3119 is used by the runtime library to unwind the stack.</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3120
3121<p>This instruction is used in languages with destructors to ensure that proper
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3122 cleanup is performed in the case of either a <tt>longjmp</tt> or a thrown
3123 exception. Additionally, this is important for implementation of
3124 '<tt>catch</tt>' clauses in high-level languages that support them.</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3125
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3126<p>For the purposes of the SSA form, the definition of the value returned by the
3127 '<tt>invoke</tt>' instruction is deemed to occur on the edge from the current
3128 block to the "normal" label. If the callee unwinds then no return value is
3129 available.</p>
Dan Gohman9069d892009-05-22 21:47:08 +0000[diff] [blame]3130
Chris Lattner97257f82010-01-15 18:08:37 +0000[diff] [blame]3131<p>Note that the code generator does not yet completely support unwind, and
3132that the invoke/unwind semantics are likely to change in future versions.</p>
3133
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3134<h5>Example:</h5>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3135<pre>
Nick Lewycky084ab472008-03-16 07:18:12 +0000[diff] [blame]3136 %retval = invoke i32 @Test(i32 15) to label %Continue
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]3137 unwind label %TestCleanup <i>; {i32}:retval set</i>
Nick Lewycky084ab472008-03-16 07:18:12 +0000[diff] [blame]3138 %retval = invoke <a href="#callingconv">coldcc</a> i32 %Testfnptr(i32 15) to label %Continue
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]3139 unwind label %TestCleanup <i>; {i32}:retval set</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3140</pre>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3141
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3142</div>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3143
Chris Lattner5ed60612003-09-03 00:41:47 +0000[diff] [blame]3144<!-- _______________________________________________________________________ -->
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3145
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3146<div class="doc_subsubsection"> <a name="i_unwind">'<tt>unwind</tt>'
3147Instruction</a> </div>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3148
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3149<div class="doc_text">
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3150
Chris Lattner5ed60612003-09-03 00:41:47 +0000[diff] [blame]3151<h5>Syntax:</h5>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3152<pre>
3153 unwind
3154</pre>
3155
Chris Lattner5ed60612003-09-03 00:41:47 +0000[diff] [blame]3156<h5>Overview:</h5>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3157<p>The '<tt>unwind</tt>' instruction unwinds the stack, continuing control flow
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3158 at the first callee in the dynamic call stack which used
3159 an <a href="#i_invoke"><tt>invoke</tt></a> instruction to perform the call.
3160 This is primarily used to implement exception handling.</p>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3161
Chris Lattner5ed60612003-09-03 00:41:47 +0000[diff] [blame]3162<h5>Semantics:</h5>
Chris Lattnerfe8519c2008-04-19 21:01:16 +0000[diff] [blame]3163<p>The '<tt>unwind</tt>' instruction causes execution of the current function to
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3164 immediately halt. The dynamic call stack is then searched for the
3165 first <a href="#i_invoke"><tt>invoke</tt></a> instruction on the call stack.
3166 Once found, execution continues at the "exceptional" destination block
3167 specified by the <tt>invoke</tt> instruction. If there is no <tt>invoke</tt>
3168 instruction in the dynamic call chain, undefined behavior results.</p>
3169
Chris Lattner97257f82010-01-15 18:08:37 +0000[diff] [blame]3170<p>Note that the code generator does not yet completely support unwind, and
3171that the invoke/unwind semantics are likely to change in future versions.</p>
3172
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3173</div>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3174
3175<!-- _______________________________________________________________________ -->
3176
3177<div class="doc_subsubsection"> <a name="i_unreachable">'<tt>unreachable</tt>'
3178Instruction</a> </div>
3179
3180<div class="doc_text">
3181
3182<h5>Syntax:</h5>
3183<pre>
3184 unreachable
3185</pre>
3186
3187<h5>Overview:</h5>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3188<p>The '<tt>unreachable</tt>' instruction has no defined semantics. This
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3189 instruction is used to inform the optimizer that a particular portion of the
3190 code is not reachable. This can be used to indicate that the code after a
3191 no-return function cannot be reached, and other facts.</p>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3192
3193<h5>Semantics:</h5>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3194<p>The '<tt>unreachable</tt>' instruction has no defined semantics.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3195
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3196</div>
3197
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3198<!-- ======================================================================= -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3199<div class="doc_subsection"> <a name="binaryops">Binary Operations</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3200
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3201<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3202
3203<p>Binary operators are used to do most of the computation in a program. They
3204 require two operands of the same type, execute an operation on them, and
3205 produce a single value. The operands might represent multiple data, as is
3206 the case with the <a href="#t_vector">vector</a> data type. The result value
3207 has the same type as its operands.</p>
3208
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3209<p>There are several different binary operators:</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3210
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3211</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3212
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3213<!-- _______________________________________________________________________ -->
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3214<div class="doc_subsubsection">
3215 <a name="i_add">'<tt>add</tt>' Instruction</a>
3216</div>
3217
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3218<div class="doc_text">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3219
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3220<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3221<pre>
Dan Gohmanb07de442009-07-20 22:41:19 +0000[diff] [blame]3222 &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]3223 &lt;result&gt; = add nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3224 &lt;result&gt; = add nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3225 &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]3226</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3227
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3228<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3229<p>The '<tt>add</tt>' instruction returns the sum of its two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3230
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3231<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3232<p>The two arguments to the '<tt>add</tt>' instruction must
3233 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3234 integer values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3235
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3236<h5>Semantics:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3237<p>The value produced is the integer sum of the two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3238
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3239<p>If the sum has unsigned overflow, the result returned is the mathematical
3240 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]3241
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3242<p>Because LLVM integers use a two's complement representation, this instruction
3243 is appropriate for both signed and unsigned integers.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3244
Dan Gohman902dfff2009-07-22 22:44:56 +0000[diff] [blame]3245<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3246 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3247 <tt>nsw</tt> keywords are present, the result value of the <tt>add</tt>
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]3248 is a <a href="#trapvalues">trap value</a> if unsigned and/or signed overflow,
3249 respectively, occurs.</p>
Dan Gohmanb07de442009-07-20 22:41:19 +0000[diff] [blame]3250
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3251<h5>Example:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3252<pre>
3253 &lt;result&gt; = add i32 4, %var <i>; yields {i32}:result = 4 + %var</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3254</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3255
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3256</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3257
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3258<!-- _______________________________________________________________________ -->
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3259<div class="doc_subsubsection">
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3260 <a name="i_fadd">'<tt>fadd</tt>' Instruction</a>
3261</div>
3262
3263<div class="doc_text">
3264
3265<h5>Syntax:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3266<pre>
3267 &lt;result&gt; = fadd &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3268</pre>
3269
3270<h5>Overview:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3271<p>The '<tt>fadd</tt>' instruction returns the sum of its two operands.</p>
3272
3273<h5>Arguments:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3274<p>The two arguments to the '<tt>fadd</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3275 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3276 floating point values. Both arguments must have identical types.</p>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3277
3278<h5>Semantics:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3279<p>The value produced is the floating point sum of the two operands.</p>
3280
3281<h5>Example:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3282<pre>
3283 &lt;result&gt; = fadd float 4.0, %var <i>; yields {float}:result = 4.0 + %var</i>
3284</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3285
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3286</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3287
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3288<!-- _______________________________________________________________________ -->
3289<div class="doc_subsubsection">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3290 <a name="i_sub">'<tt>sub</tt>' Instruction</a>
3291</div>
3292
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3293<div class="doc_text">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3294
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3295<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3296<pre>
Dan Gohman902dfff2009-07-22 22:44:56 +0000[diff] [blame]3297 &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]3298 &lt;result&gt; = sub nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3299 &lt;result&gt; = sub nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3300 &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]3301</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3302
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3303<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3304<p>The '<tt>sub</tt>' instruction returns the difference of its two
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3305 operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3306
3307<p>Note that the '<tt>sub</tt>' instruction is used to represent the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3308 '<tt>neg</tt>' instruction present in most other intermediate
3309 representations.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3310
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3311<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3312<p>The two arguments to the '<tt>sub</tt>' instruction must
3313 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3314 integer values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3315
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3316<h5>Semantics:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3317<p>The value produced is the integer difference of the two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3318
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3319<p>If the difference has unsigned overflow, the result returned is the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3320 mathematical result modulo 2<sup>n</sup>, where n is the bit width of the
3321 result.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3322
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3323<p>Because LLVM integers use a two's complement representation, this instruction
3324 is appropriate for both signed and unsigned integers.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3325
Dan Gohman902dfff2009-07-22 22:44:56 +0000[diff] [blame]3326<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3327 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3328 <tt>nsw</tt> keywords are present, the result value of the <tt>sub</tt>
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]3329 is a <a href="#trapvalues">trap value</a> if unsigned and/or signed overflow,
3330 respectively, occurs.</p>
Dan Gohmanb07de442009-07-20 22:41:19 +0000[diff] [blame]3331
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3332<h5>Example:</h5>
Bill Wendling2d8b9a82007-05-29 09:42:13 +0000[diff] [blame]3333<pre>
3334 &lt;result&gt; = sub i32 4, %var <i>; yields {i32}:result = 4 - %var</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3335 &lt;result&gt; = sub i32 0, %val <i>; yields {i32}:result = -%var</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3336</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3337
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3338</div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3339
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3340<!-- _______________________________________________________________________ -->
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3341<div class="doc_subsubsection">
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3342 <a name="i_fsub">'<tt>fsub</tt>' Instruction</a>
3343</div>
3344
3345<div class="doc_text">
3346
3347<h5>Syntax:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3348<pre>
3349 &lt;result&gt; = fsub &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3350</pre>
3351
3352<h5>Overview:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3353<p>The '<tt>fsub</tt>' instruction returns the difference of its two
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3354 operands.</p>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3355
3356<p>Note that the '<tt>fsub</tt>' instruction is used to represent the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3357 '<tt>fneg</tt>' instruction present in most other intermediate
3358 representations.</p>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3359
3360<h5>Arguments:</h5>
Bill Wendling972b7202009-07-20 02:32:41 +0000[diff] [blame]3361<p>The two arguments to the '<tt>fsub</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3362 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3363 floating point values. Both arguments must have identical types.</p>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3364
3365<h5>Semantics:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3366<p>The value produced is the floating point difference of the two operands.</p>
3367
3368<h5>Example:</h5>
3369<pre>
3370 &lt;result&gt; = fsub float 4.0, %var <i>; yields {float}:result = 4.0 - %var</i>
3371 &lt;result&gt; = fsub float -0.0, %val <i>; yields {float}:result = -%var</i>
3372</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3373
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3374</div>
3375
3376<!-- _______________________________________________________________________ -->
3377<div class="doc_subsubsection">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3378 <a name="i_mul">'<tt>mul</tt>' Instruction</a>
3379</div>
3380
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3381<div class="doc_text">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3382
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3383<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3384<pre>
Dan Gohman902dfff2009-07-22 22:44:56 +0000[diff] [blame]3385 &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]3386 &lt;result&gt; = mul nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3387 &lt;result&gt; = mul nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3388 &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]3389</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3390
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3391<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3392<p>The '<tt>mul</tt>' instruction returns the product of its two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3393
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3394<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3395<p>The two arguments to the '<tt>mul</tt>' instruction must
3396 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3397 integer values. Both arguments must have identical types.</p>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3398
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3399<h5>Semantics:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3400<p>The value produced is the integer product of the two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3401
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3402<p>If the result of the multiplication has unsigned overflow, the result
3403 returned is the mathematical result modulo 2<sup>n</sup>, where n is the bit
3404 width of the result.</p>
3405
3406<p>Because LLVM integers use a two's complement representation, and the result
3407 is the same width as the operands, this instruction returns the correct
3408 result for both signed and unsigned integers. If a full product
3409 (e.g. <tt>i32</tt>x<tt>i32</tt>-><tt>i64</tt>) is needed, the operands should
3410 be sign-extended or zero-extended as appropriate to the width of the full
3411 product.</p>
3412
Dan Gohman902dfff2009-07-22 22:44:56 +0000[diff] [blame]3413<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3414 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3415 <tt>nsw</tt> keywords are present, the result value of the <tt>mul</tt>
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]3416 is a <a href="#trapvalues">trap value</a> if unsigned and/or signed overflow,
3417 respectively, occurs.</p>
Dan Gohmanb07de442009-07-20 22:41:19 +0000[diff] [blame]3418
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3419<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3420<pre>
3421 &lt;result&gt; = mul i32 4, %var <i>; yields {i32}:result = 4 * %var</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3422</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3423
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3424</div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3425
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3426<!-- _______________________________________________________________________ -->
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3427<div class="doc_subsubsection">
3428 <a name="i_fmul">'<tt>fmul</tt>' Instruction</a>
3429</div>
3430
3431<div class="doc_text">
3432
3433<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3434<pre>
3435 &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]3436</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3437
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3438<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3439<p>The '<tt>fmul</tt>' instruction returns the product of its two operands.</p>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3440
3441<h5>Arguments:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3442<p>The two arguments to the '<tt>fmul</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3443 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3444 floating point values. Both arguments must have identical types.</p>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3445
3446<h5>Semantics:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3447<p>The value produced is the floating point product of the two operands.</p>
3448
3449<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3450<pre>
3451 &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]3452</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3453
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3454</div>
3455
3456<!-- _______________________________________________________________________ -->
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3457<div class="doc_subsubsection"> <a name="i_udiv">'<tt>udiv</tt>' Instruction
3458</a></div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3459
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3460<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3461
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3462<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3463<pre>
3464 &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]3465</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3466
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3467<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3468<p>The '<tt>udiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3469
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3470<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3471<p>The two arguments to the '<tt>udiv</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3472 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3473 values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3474
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3475<h5>Semantics:</h5>
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3476<p>The value produced is the unsigned integer quotient of the two operands.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3477
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3478<p>Note that unsigned integer division and signed integer division are distinct
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3479 operations; for signed integer division, use '<tt>sdiv</tt>'.</p>
3480
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3481<p>Division by zero leads to undefined behavior.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3482
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3483<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3484<pre>
3485 &lt;result&gt; = udiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3486</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3487
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3488</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3489
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3490<!-- _______________________________________________________________________ -->
3491<div class="doc_subsubsection"> <a name="i_sdiv">'<tt>sdiv</tt>' Instruction
3492</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3493
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3494<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3495
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3496<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3497<pre>
Dan Gohmanb07de442009-07-20 22:41:19 +0000[diff] [blame]3498 &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]3499 &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]3500</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3501
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3502<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3503<p>The '<tt>sdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3504
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3505<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3506<p>The two arguments to the '<tt>sdiv</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3507 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3508 values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3509
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3510<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3511<p>The value produced is the signed integer quotient of the two operands rounded
3512 towards zero.</p>
3513
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3514<p>Note that signed integer division and unsigned integer division are distinct
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3515 operations; for unsigned integer division, use '<tt>udiv</tt>'.</p>
3516
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3517<p>Division by zero leads to undefined behavior. Overflow also leads to
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3518 undefined behavior; this is a rare case, but can occur, for example, by doing
3519 a 32-bit division of -2147483648 by -1.</p>
3520
Dan Gohman71dfd782009-07-22 00:04:19 +0000[diff] [blame]3521<p>If the <tt>exact</tt> keyword is present, the result value of the
Dan Gohman57255802010-04-23 15:23:32 +0000[diff] [blame]3522 <tt>sdiv</tt> is a <a href="#trapvalues">trap value</a> if the result would
3523 be rounded or if overflow would occur.</p>
Dan Gohmanb07de442009-07-20 22:41:19 +0000[diff] [blame]3524
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3525<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3526<pre>
3527 &lt;result&gt; = sdiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3528</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3529
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3530</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3531
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3532<!-- _______________________________________________________________________ -->
3533<div class="doc_subsubsection"> <a name="i_fdiv">'<tt>fdiv</tt>'
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3534Instruction</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3535
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3536<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3537
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3538<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3539<pre>
Gabor Greif0f75ad02008-08-07 21:46:00 +0000[diff] [blame]3540 &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]3541</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3542
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3543<h5>Overview:</h5>
3544<p>The '<tt>fdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3545
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3546<h5>Arguments:</h5>
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]3547<p>The two arguments to the '<tt>fdiv</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3548 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3549 floating point values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3550
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3551<h5>Semantics:</h5>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3552<p>The value produced is the floating point quotient of the two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3553
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3554<h5>Example:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3555<pre>
3556 &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]3557</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3558
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3559</div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3560
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3561<!-- _______________________________________________________________________ -->
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3562<div class="doc_subsubsection"> <a name="i_urem">'<tt>urem</tt>' Instruction</a>
3563</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3564
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3565<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3566
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3567<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3568<pre>
3569 &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]3570</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3571
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3572<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3573<p>The '<tt>urem</tt>' instruction returns the remainder from the unsigned
3574 division of its two arguments.</p>
3575
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3576<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3577<p>The two arguments to the '<tt>urem</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3578 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3579 values. Both arguments must have identical types.</p>
3580
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3581<h5>Semantics:</h5>
3582<p>This instruction returns the unsigned integer <i>remainder</i> of a division.
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3583 This instruction always performs an unsigned division to get the
3584 remainder.</p>
3585
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3586<p>Note that unsigned integer remainder and signed integer remainder are
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3587 distinct operations; for signed integer remainder, use '<tt>srem</tt>'.</p>
3588
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3589<p>Taking the remainder of a division by zero leads to undefined behavior.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3590
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3591<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3592<pre>
3593 &lt;result&gt; = urem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3594</pre>
3595
3596</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3597
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3598<!-- _______________________________________________________________________ -->
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3599<div class="doc_subsubsection">
3600 <a name="i_srem">'<tt>srem</tt>' Instruction</a>
3601</div>
3602
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3603<div class="doc_text">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3604
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3605<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3606<pre>
Gabor Greif0f75ad02008-08-07 21:46:00 +0000[diff] [blame]3607 &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]3608</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3609
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3610<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3611<p>The '<tt>srem</tt>' instruction returns the remainder from the signed
3612 division of its two operands. This instruction can also take
3613 <a href="#t_vector">vector</a> versions of the values in which case the
3614 elements must be integers.</p>
Chris Lattnerb8f816e2008-01-04 04:33:49 +0000[diff] [blame]3615
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3616<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3617<p>The two arguments to the '<tt>srem</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3618 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3619 values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3620
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3621<h5>Semantics:</h5>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3622<p>This instruction returns the <i>remainder</i> of a division (where the result
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3623 has the same sign as the dividend, <tt>op1</tt>), not the <i>modulo</i>
3624 operator (where the result has the same sign as the divisor, <tt>op2</tt>) of
3625 a value. For more information about the difference,
3626 see <a href="http://mathforum.org/dr.math/problems/anne.4.28.99.html">The
3627 Math Forum</a>. For a table of how this is implemented in various languages,
3628 please see <a href="http://en.wikipedia.org/wiki/Modulo_operation">
3629 Wikipedia: modulo operation</a>.</p>
3630
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3631<p>Note that signed integer remainder and unsigned integer remainder are
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3632 distinct operations; for unsigned integer remainder, use '<tt>urem</tt>'.</p>
3633
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3634<p>Taking the remainder of a division by zero leads to undefined behavior.
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3635 Overflow also leads to undefined behavior; this is a rare case, but can
3636 occur, for example, by taking the remainder of a 32-bit division of
3637 -2147483648 by -1. (The remainder doesn't actually overflow, but this rule
3638 lets srem be implemented using instructions that return both the result of
3639 the division and the remainder.)</p>
3640
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3641<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3642<pre>
3643 &lt;result&gt; = srem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3644</pre>
3645
3646</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3647
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3648<!-- _______________________________________________________________________ -->
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3649<div class="doc_subsubsection">
3650 <a name="i_frem">'<tt>frem</tt>' Instruction</a> </div>
3651
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3652<div class="doc_text">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3653
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3654<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3655<pre>
3656 &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]3657</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3658
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3659<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3660<p>The '<tt>frem</tt>' instruction returns the remainder from the division of
3661 its two operands.</p>
3662
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3663<h5>Arguments:</h5>
3664<p>The two arguments to the '<tt>frem</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3665 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3666 floating point values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3667
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3668<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3669<p>This instruction returns the <i>remainder</i> of a division. The remainder
3670 has the same sign as the dividend.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3671
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3672<h5>Example:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3673<pre>
3674 &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]3675</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3676
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3677</div>
Robert Bocchino820bc75b2006-02-17 21:18:08 +0000[diff] [blame]3678
Reid Spencer2ab01932007-02-02 13:57:07 +0000[diff] [blame]3679<!-- ======================================================================= -->
3680<div class="doc_subsection"> <a name="bitwiseops">Bitwise Binary
3681Operations</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3682
Reid Spencer2ab01932007-02-02 13:57:07 +0000[diff] [blame]3683<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3684
3685<p>Bitwise binary operators are used to do various forms of bit-twiddling in a
3686 program. They are generally very efficient instructions and can commonly be
3687 strength reduced from other instructions. They require two operands of the
3688 same type, execute an operation on them, and produce a single value. The
3689 resulting value is the same type as its operands.</p>
3690
Reid Spencer2ab01932007-02-02 13:57:07 +0000[diff] [blame]3691</div>
3692
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3693<!-- _______________________________________________________________________ -->
3694<div class="doc_subsubsection"> <a name="i_shl">'<tt>shl</tt>'
3695Instruction</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3696
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3697<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3698
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3699<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3700<pre>
3701 &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]3702</pre>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]3703
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3704<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3705<p>The '<tt>shl</tt>' instruction returns the first operand shifted to the left
3706 a specified number of bits.</p>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]3707
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3708<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3709<p>Both arguments to the '<tt>shl</tt>' instruction must be the
3710 same <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3711 integer type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3712
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3713<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3714<p>The value produced is <tt>op1</tt> * 2<sup><tt>op2</tt></sup> mod
3715 2<sup>n</sup>, where <tt>n</tt> is the width of the result. If <tt>op2</tt>
3716 is (statically or dynamically) negative or equal to or larger than the number
3717 of bits in <tt>op1</tt>, the result is undefined. If the arguments are
3718 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
3719 shift amount in <tt>op2</tt>.</p>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]3720
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3721<h5>Example:</h5>
3722<pre>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3723 &lt;result&gt; = shl i32 4, %var <i>; yields {i32}: 4 &lt;&lt; %var</i>
3724 &lt;result&gt; = shl i32 4, 2 <i>; yields {i32}: 16</i>
3725 &lt;result&gt; = shl i32 1, 10 <i>; yields {i32}: 1024</i>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]3726 &lt;result&gt; = shl i32 1, 32 <i>; undefined</i>
Mon P Wang4dd832d2008-12-09 05:46:39 +0000[diff] [blame]3727 &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]3728</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3729
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3730</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3731
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3732<!-- _______________________________________________________________________ -->
3733<div class="doc_subsubsection"> <a name="i_lshr">'<tt>lshr</tt>'
3734Instruction</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3735
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3736<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3737
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3738<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3739<pre>
3740 &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]3741</pre>
3742
3743<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3744<p>The '<tt>lshr</tt>' instruction (logical shift right) returns the first
3745 operand shifted to the right a specified number of bits with zero fill.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3746
3747<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3748<p>Both arguments to the '<tt>lshr</tt>' instruction must be the same
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3749 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3750 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3751
3752<h5>Semantics:</h5>
3753<p>This instruction always performs a logical shift right operation. The most
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3754 significant bits of the result will be filled with zero bits after the shift.
3755 If <tt>op2</tt> is (statically or dynamically) equal to or larger than the
3756 number of bits in <tt>op1</tt>, the result is undefined. If the arguments are
3757 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
3758 shift amount in <tt>op2</tt>.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3759
3760<h5>Example:</h5>
3761<pre>
3762 &lt;result&gt; = lshr i32 4, 1 <i>; yields {i32}:result = 2</i>
3763 &lt;result&gt; = lshr i32 4, 2 <i>; yields {i32}:result = 1</i>
3764 &lt;result&gt; = lshr i8 4, 3 <i>; yields {i8}:result = 0</i>
3765 &lt;result&gt; = lshr i8 -2, 1 <i>; yields {i8}:result = 0x7FFFFFFF </i>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]3766 &lt;result&gt; = lshr i32 1, 32 <i>; undefined</i>
Mon P Wang4dd832d2008-12-09 05:46:39 +0000[diff] [blame]3767 &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]3768</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3769
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3770</div>
3771
Reid Spencer2ab01932007-02-02 13:57:07 +0000[diff] [blame]3772<!-- _______________________________________________________________________ -->
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3773<div class="doc_subsubsection"> <a name="i_ashr">'<tt>ashr</tt>'
3774Instruction</a> </div>
3775<div class="doc_text">
3776
3777<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3778<pre>
3779 &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]3780</pre>
3781
3782<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3783<p>The '<tt>ashr</tt>' instruction (arithmetic shift right) returns the first
3784 operand shifted to the right a specified number of bits with sign
3785 extension.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3786
3787<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3788<p>Both arguments to the '<tt>ashr</tt>' instruction must be the same
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3789 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3790 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3791
3792<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3793<p>This instruction always performs an arithmetic shift right operation, The
3794 most significant bits of the result will be filled with the sign bit
3795 of <tt>op1</tt>. If <tt>op2</tt> is (statically or dynamically) equal to or
3796 larger than the number of bits in <tt>op1</tt>, the result is undefined. If
3797 the arguments are vectors, each vector element of <tt>op1</tt> is shifted by
3798 the corresponding shift amount in <tt>op2</tt>.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3799
3800<h5>Example:</h5>
3801<pre>
3802 &lt;result&gt; = ashr i32 4, 1 <i>; yields {i32}:result = 2</i>
3803 &lt;result&gt; = ashr i32 4, 2 <i>; yields {i32}:result = 1</i>
3804 &lt;result&gt; = ashr i8 4, 3 <i>; yields {i8}:result = 0</i>
3805 &lt;result&gt; = ashr i8 -2, 1 <i>; yields {i8}:result = -1</i>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]3806 &lt;result&gt; = ashr i32 1, 32 <i>; undefined</i>
Mon P Wang4dd832d2008-12-09 05:46:39 +0000[diff] [blame]3807 &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]3808</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3809
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3810</div>
3811
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3812<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3813<div class="doc_subsubsection"> <a name="i_and">'<tt>and</tt>'
3814Instruction</a> </div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3815
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3816<div class="doc_text">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3817
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3818<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3819<pre>
Gabor Greif0f75ad02008-08-07 21:46:00 +0000[diff] [blame]3820 &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]3821</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3822
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3823<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3824<p>The '<tt>and</tt>' instruction returns the bitwise logical and of its two
3825 operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3826
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3827<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3828<p>The two arguments to the '<tt>and</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3829 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3830 values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3831
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3832<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3833<p>The truth table used for the '<tt>and</tt>' instruction is:</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3834
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3835<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3836 <tbody>
3837 <tr>
3838 <td>In0</td>
3839 <td>In1</td>
3840 <td>Out</td>
3841 </tr>
3842 <tr>
3843 <td>0</td>
3844 <td>0</td>
3845 <td>0</td>
3846 </tr>
3847 <tr>
3848 <td>0</td>
3849 <td>1</td>
3850 <td>0</td>
3851 </tr>
3852 <tr>
3853 <td>1</td>
3854 <td>0</td>
3855 <td>0</td>
3856 </tr>
3857 <tr>
3858 <td>1</td>
3859 <td>1</td>
3860 <td>1</td>
3861 </tr>
3862 </tbody>
3863</table>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3864
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3865<h5>Example:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3866<pre>
3867 &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]3868 &lt;result&gt; = and i32 15, 40 <i>; yields {i32}:result = 8</i>
3869 &lt;result&gt; = and i32 4, 8 <i>; yields {i32}:result = 0</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3870</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3871</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3872<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3873<div class="doc_subsubsection"> <a name="i_or">'<tt>or</tt>' Instruction</a> </div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3874
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3875<div class="doc_text">
3876
3877<h5>Syntax:</h5>
3878<pre>
3879 &lt;result&gt; = or &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3880</pre>
3881
3882<h5>Overview:</h5>
3883<p>The '<tt>or</tt>' instruction returns the bitwise logical inclusive or of its
3884 two operands.</p>
3885
3886<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3887<p>The two arguments to the '<tt>or</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3888 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3889 values. Both arguments must have identical types.</p>
3890
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3891<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3892<p>The truth table used for the '<tt>or</tt>' instruction is:</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3893
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3894<table border="1" cellspacing="0" cellpadding="4">
3895 <tbody>
3896 <tr>
3897 <td>In0</td>
3898 <td>In1</td>
3899 <td>Out</td>
3900 </tr>
3901 <tr>
3902 <td>0</td>
3903 <td>0</td>
3904 <td>0</td>
3905 </tr>
3906 <tr>
3907 <td>0</td>
3908 <td>1</td>
3909 <td>1</td>
3910 </tr>
3911 <tr>
3912 <td>1</td>
3913 <td>0</td>
3914 <td>1</td>
3915 </tr>
3916 <tr>
3917 <td>1</td>
3918 <td>1</td>
3919 <td>1</td>
3920 </tr>
3921 </tbody>
3922</table>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3923
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3924<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3925<pre>
3926 &lt;result&gt; = or i32 4, %var <i>; yields {i32}:result = 4 | %var</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3927 &lt;result&gt; = or i32 15, 40 <i>; yields {i32}:result = 47</i>
3928 &lt;result&gt; = or i32 4, 8 <i>; yields {i32}:result = 12</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3929</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3930
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3931</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3932
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3933<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3934<div class="doc_subsubsection"> <a name="i_xor">'<tt>xor</tt>'
3935Instruction</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3936
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3937<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3938
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3939<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3940<pre>
3941 &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]3942</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3943
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3944<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3945<p>The '<tt>xor</tt>' instruction returns the bitwise logical exclusive or of
3946 its two operands. The <tt>xor</tt> is used to implement the "one's
3947 complement" operation, which is the "~" operator in C.</p>
3948
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3949<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3950<p>The two arguments to the '<tt>xor</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3951 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3952 values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3953
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3954<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3955<p>The truth table used for the '<tt>xor</tt>' instruction is:</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3956
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3957<table border="1" cellspacing="0" cellpadding="4">
3958 <tbody>
3959 <tr>
3960 <td>In0</td>
3961 <td>In1</td>
3962 <td>Out</td>
3963 </tr>
3964 <tr>
3965 <td>0</td>
3966 <td>0</td>
3967 <td>0</td>
3968 </tr>
3969 <tr>
3970 <td>0</td>
3971 <td>1</td>
3972 <td>1</td>
3973 </tr>
3974 <tr>
3975 <td>1</td>
3976 <td>0</td>
3977 <td>1</td>
3978 </tr>
3979 <tr>
3980 <td>1</td>
3981 <td>1</td>
3982 <td>0</td>
3983 </tr>
3984 </tbody>
3985</table>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3986
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3987<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3988<pre>
3989 &lt;result&gt; = xor i32 4, %var <i>; yields {i32}:result = 4 ^ %var</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3990 &lt;result&gt; = xor i32 15, 40 <i>; yields {i32}:result = 39</i>
3991 &lt;result&gt; = xor i32 4, 8 <i>; yields {i32}:result = 12</i>
3992 &lt;result&gt; = xor i32 %V, -1 <i>; yields {i32}:result = ~%V</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3993</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3994
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3995</div>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3996
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3997<!-- ======================================================================= -->
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3998<div class="doc_subsection">
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]3999 <a name="vectorops">Vector Operations</a>
4000</div>
4001
4002<div class="doc_text">
4003
4004<p>LLVM supports several instructions to represent vector operations in a
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4005 target-independent manner. These instructions cover the element-access and
4006 vector-specific operations needed to process vectors effectively. While LLVM
4007 does directly support these vector operations, many sophisticated algorithms
4008 will want to use target-specific intrinsics to take full advantage of a
4009 specific target.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4010
4011</div>
4012
4013<!-- _______________________________________________________________________ -->
4014<div class="doc_subsubsection">
4015 <a name="i_extractelement">'<tt>extractelement</tt>' Instruction</a>
4016</div>
4017
4018<div class="doc_text">
4019
4020<h5>Syntax:</h5>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4021<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4022 &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]4023</pre>
4024
4025<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4026<p>The '<tt>extractelement</tt>' instruction extracts a single scalar element
4027 from a vector at a specified index.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4028
4029
4030<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4031<p>The first operand of an '<tt>extractelement</tt>' instruction is a value
4032 of <a href="#t_vector">vector</a> type. The second operand is an index
4033 indicating the position from which to extract the element. The index may be
4034 a variable.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4035
4036<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4037<p>The result is a scalar of the same type as the element type of
4038 <tt>val</tt>. Its value is the value at position <tt>idx</tt> of
4039 <tt>val</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
4040 results are undefined.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4041
4042<h5>Example:</h5>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4043<pre>
Gabor Greif03ab4dc2009-10-28 13:14:50 +0000[diff] [blame]4044 &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]4045</pre>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4046
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4047</div>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4048
4049<!-- _______________________________________________________________________ -->
4050<div class="doc_subsubsection">
4051 <a name="i_insertelement">'<tt>insertelement</tt>' Instruction</a>
4052</div>
4053
4054<div class="doc_text">
4055
4056<h5>Syntax:</h5>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4057<pre>
Dan Gohman43ba0672008-05-12 23:38:42 +0000[diff] [blame]4058 &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]4059</pre>
4060
4061<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4062<p>The '<tt>insertelement</tt>' instruction inserts a scalar element into a
4063 vector at a specified index.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4064
4065<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4066<p>The first operand of an '<tt>insertelement</tt>' instruction is a value
4067 of <a href="#t_vector">vector</a> type. The second operand is a scalar value
4068 whose type must equal the element type of the first operand. The third
4069 operand is an index indicating the position at which to insert the value.
4070 The index may be a variable.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4071
4072<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4073<p>The result is a vector of the same type as <tt>val</tt>. Its element values
4074 are those of <tt>val</tt> except at position <tt>idx</tt>, where it gets the
4075 value <tt>elt</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
4076 results are undefined.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4077
4078<h5>Example:</h5>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4079<pre>
Gabor Greif03ab4dc2009-10-28 13:14:50 +0000[diff] [blame]4080 &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]4081</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4082
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4083</div>
4084
4085<!-- _______________________________________________________________________ -->
4086<div class="doc_subsubsection">
4087 <a name="i_shufflevector">'<tt>shufflevector</tt>' Instruction</a>
4088</div>
4089
4090<div class="doc_text">
4091
4092<h5>Syntax:</h5>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4093<pre>
Mon P Wang25f01062008-11-10 04:46:22 +0000[diff] [blame]4094 &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]4095</pre>
4096
4097<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4098<p>The '<tt>shufflevector</tt>' instruction constructs a permutation of elements
4099 from two input vectors, returning a vector with the same element type as the
4100 input and length that is the same as the shuffle mask.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4101
4102<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4103<p>The first two operands of a '<tt>shufflevector</tt>' instruction are vectors
4104 with types that match each other. The third argument is a shuffle mask whose
4105 element type is always 'i32'. The result of the instruction is a vector
4106 whose length is the same as the shuffle mask and whose element type is the
4107 same as the element type of the first two operands.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4108
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4109<p>The shuffle mask operand is required to be a constant vector with either
4110 constant integer or undef values.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4111
4112<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4113<p>The elements of the two input vectors are numbered from left to right across
4114 both of the vectors. The shuffle mask operand specifies, for each element of
4115 the result vector, which element of the two input vectors the result element
4116 gets. The element selector may be undef (meaning "don't care") and the
4117 second operand may be undef if performing a shuffle from only one vector.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4118
4119<h5>Example:</h5>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4120<pre>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4121 &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]4122 &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]4123 &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]4124 &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]4125 &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]4126 &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]4127 &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]4128 &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]4129</pre>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4130
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4131</div>
Tanya Lattnerb138bbe2006-04-14 19:24:33 +0000[diff] [blame]4132
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4133<!-- ======================================================================= -->
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4134<div class="doc_subsection">
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4135 <a name="aggregateops">Aggregate Operations</a>
4136</div>
4137
4138<div class="doc_text">
4139
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]4140<p>LLVM supports several instructions for working with
4141 <a href="#t_aggregate">aggregate</a> values.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4142
4143</div>
4144
4145<!-- _______________________________________________________________________ -->
4146<div class="doc_subsubsection">
4147 <a name="i_extractvalue">'<tt>extractvalue</tt>' Instruction</a>
4148</div>
4149
4150<div class="doc_text">
4151
4152<h5>Syntax:</h5>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4153<pre>
4154 &lt;result&gt; = extractvalue &lt;aggregate type&gt; &lt;val&gt;, &lt;idx&gt;{, &lt;idx&gt;}*
4155</pre>
4156
4157<h5>Overview:</h5>
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]4158<p>The '<tt>extractvalue</tt>' instruction extracts the value of a member field
4159 from an <a href="#t_aggregate">aggregate</a> value.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4160
4161<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4162<p>The first operand of an '<tt>extractvalue</tt>' instruction is a value
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]4163 of <a href="#t_struct">struct</a>, <a href="#t_union">union</a> or
4164 <a href="#t_array">array</a> type. The operands are constant indices to
4165 specify which value to extract in a similar manner as indices in a
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4166 '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4167
4168<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4169<p>The result is the value at the position in the aggregate specified by the
4170 index operands.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4171
4172<h5>Example:</h5>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4173<pre>
Gabor Greif03ab4dc2009-10-28 13:14:50 +0000[diff] [blame]4174 &lt;result&gt; = extractvalue {i32, float} %agg, 0 <i>; yields i32</i>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4175</pre>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4176
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4177</div>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4178
4179<!-- _______________________________________________________________________ -->
4180<div class="doc_subsubsection">
4181 <a name="i_insertvalue">'<tt>insertvalue</tt>' Instruction</a>
4182</div>
4183
4184<div class="doc_text">
4185
4186<h5>Syntax:</h5>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4187<pre>
Jeffrey Yasskinf991bbb2010-01-11 19:19:26 +0000[diff] [blame]4188 &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]4189</pre>
4190
4191<h5>Overview:</h5>
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]4192<p>The '<tt>insertvalue</tt>' instruction inserts a value into a member field
4193 in an <a href="#t_aggregate">aggregate</a> value.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4194
4195<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4196<p>The first operand of an '<tt>insertvalue</tt>' instruction is a value
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]4197 of <a href="#t_struct">struct</a>, <a href="#t_union">union</a> or
4198 <a href="#t_array">array</a> type. The second operand is a first-class
4199 value to insert. The following operands are constant indices indicating
4200 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]4201 '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction. The
4202 value to insert must have the same type as the value identified by the
4203 indices.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4204
4205<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4206<p>The result is an aggregate of the same type as <tt>val</tt>. Its value is
4207 that of <tt>val</tt> except that the value at the position specified by the
4208 indices is that of <tt>elt</tt>.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4209
4210<h5>Example:</h5>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4211<pre>
Jeffrey Yasskinf991bbb2010-01-11 19:19:26 +0000[diff] [blame]4212 %agg1 = insertvalue {i32, float} undef, i32 1, 0 <i>; yields {i32 1, float undef}</i>
4213 %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]4214</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4215
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4216</div>
4217
4218
4219<!-- ======================================================================= -->
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4220<div class="doc_subsection">
Chris Lattner6ab66722006-08-15 00:45:58 +0000[diff] [blame]4221 <a name="memoryops">Memory Access and Addressing Operations</a>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4222</div>
4223
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4224<div class="doc_text">
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4225
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4226<p>A key design point of an SSA-based representation is how it represents
4227 memory. In LLVM, no memory locations are in SSA form, which makes things
Victor Hernandeza70c6df2009-10-26 23:44:29 +0000[diff] [blame]4228 very simple. This section describes how to read, write, and allocate
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4229 memory in LLVM.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4230
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4231</div>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4232
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4233<!-- _______________________________________________________________________ -->
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4234<div class="doc_subsubsection">
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4235 <a name="i_alloca">'<tt>alloca</tt>' Instruction</a>
4236</div>
4237
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4238<div class="doc_text">
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4239
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4240<h5>Syntax:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4241<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4242 &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]4243</pre>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4244
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4245<h5>Overview:</h5>
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]4246<p>The '<tt>alloca</tt>' instruction allocates memory on the stack frame of the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4247 currently executing function, to be automatically released when this function
4248 returns to its caller. The object is always allocated in the generic address
4249 space (address space zero).</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4250
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4251<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4252<p>The '<tt>alloca</tt>' instruction
4253 allocates <tt>sizeof(&lt;type&gt;)*NumElements</tt> bytes of memory on the
4254 runtime stack, returning a pointer of the appropriate type to the program.
4255 If "NumElements" is specified, it is the number of elements allocated,
4256 otherwise "NumElements" is defaulted to be one. If a constant alignment is
4257 specified, the value result of the allocation is guaranteed to be aligned to
4258 at least that boundary. If not specified, or if zero, the target can choose
4259 to align the allocation on any convenient boundary compatible with the
4260 type.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4261
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4262<p>'<tt>type</tt>' may be any sized type.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4263
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4264<h5>Semantics:</h5>
Bill Wendling9ee6a312009-05-08 20:49:29 +0000[diff] [blame]4265<p>Memory is allocated; a pointer is returned. The operation is undefined if
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4266 there is insufficient stack space for the allocation. '<tt>alloca</tt>'d
4267 memory is automatically released when the function returns. The
4268 '<tt>alloca</tt>' instruction is commonly used to represent automatic
4269 variables that must have an address available. When the function returns
4270 (either with the <tt><a href="#i_ret">ret</a></tt>
4271 or <tt><a href="#i_unwind">unwind</a></tt> instructions), the memory is
4272 reclaimed. Allocating zero bytes is legal, but the result is undefined.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4273
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4274<h5>Example:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4275<pre>
Dan Gohman7a5acb52009-01-04 23:49:44 +0000[diff] [blame]4276 %ptr = alloca i32 <i>; yields {i32*}:ptr</i>
4277 %ptr = alloca i32, i32 4 <i>; yields {i32*}:ptr</i>
4278 %ptr = alloca i32, i32 4, align 1024 <i>; yields {i32*}:ptr</i>
4279 %ptr = alloca i32, align 1024 <i>; yields {i32*}:ptr</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4280</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4281
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4282</div>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4283
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4284<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]4285<div class="doc_subsubsection"> <a name="i_load">'<tt>load</tt>'
4286Instruction</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4287
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4288<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4289
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4290<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4291<pre>
Bill Wendlingbc4024f2010-02-25 21:23:24 +0000[diff] [blame]4292 &lt;result&gt; = load &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;][, !nontemporal !&lt;index&gt;]
4293 &lt;result&gt; = volatile load &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;][, !nontemporal !&lt;index&gt;]
4294 !&lt;index&gt; = !{ i32 1 }
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4295</pre>
4296
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4297<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4298<p>The '<tt>load</tt>' instruction is used to read from memory.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4299
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4300<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4301<p>The argument to the '<tt>load</tt>' instruction specifies the memory address
4302 from which to load. The pointer must point to
4303 a <a href="#t_firstclass">first class</a> type. If the <tt>load</tt> is
4304 marked as <tt>volatile</tt>, then the optimizer is not allowed to modify the
Jeffrey Yasskin5d284ae2010-04-26 21:21:24 +0000[diff] [blame]4305 number or order of execution of this <tt>load</tt> with other <a
4306 href="#volatile">volatile operations</a>.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4307
Bill Wendlingbc4024f2010-02-25 21:23:24 +0000[diff] [blame]4308<p>The optional constant <tt>align</tt> argument specifies the alignment of the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4309 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]4310 omitted <tt>align</tt> argument means that the operation has the preferential
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4311 alignment for the target. It is the responsibility of the code emitter to
4312 ensure that the alignment information is correct. Overestimating the
Bill Wendlingbc4024f2010-02-25 21:23:24 +0000[diff] [blame]4313 alignment results in undefined behavior. Underestimating the alignment may
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4314 produce less efficient code. An alignment of 1 is always safe.</p>
4315
Bill Wendlingbc4024f2010-02-25 21:23:24 +0000[diff] [blame]4316<p>The optional <tt>!nontemporal</tt> metadata must reference a single
4317 metatadata name &lt;index&gt; corresponding to a metadata node with
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]4318 one <tt>i32</tt> entry of value 1. The existence of
Bill Wendlingbc4024f2010-02-25 21:23:24 +0000[diff] [blame]4319 the <tt>!nontemporal</tt> metatadata on the instruction tells the optimizer
4320 and code generator that this load is not expected to be reused in the cache.
4321 The code generator may select special instructions to save cache bandwidth,
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]4322 such as the <tt>MOVNT</tt> instruction on x86.</p>
David Greene9641d062010-02-16 20:50:18 +0000[diff] [blame]4323
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4324<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4325<p>The location of memory pointed to is loaded. If the value being loaded is of
4326 scalar type then the number of bytes read does not exceed the minimum number
4327 of bytes needed to hold all bits of the type. For example, loading an
4328 <tt>i24</tt> reads at most three bytes. When loading a value of a type like
4329 <tt>i20</tt> with a size that is not an integral number of bytes, the result
4330 is undefined if the value was not originally written using a store of the
4331 same type.</p>
4332
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4333<h5>Examples:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4334<pre>
4335 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
4336 <a href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4337 %val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4338</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4339
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4340</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4341
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4342<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]4343<div class="doc_subsubsection"> <a name="i_store">'<tt>store</tt>'
4344Instruction</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4345
Reid Spencera89fb182006-11-09 21:18:01 +0000[diff] [blame]4346<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4347
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4348<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4349<pre>
David Greene9641d062010-02-16 20:50:18 +0000[diff] [blame]4350 store &lt;ty&gt; &lt;value&gt;, &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;][, !nontemporal !<index>] <i>; yields {void}</i>
4351 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]4352</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4353
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4354<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4355<p>The '<tt>store</tt>' instruction is used to write to memory.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4356
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4357<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4358<p>There are two arguments to the '<tt>store</tt>' instruction: a value to store
4359 and an address at which to store it. The type of the
4360 '<tt>&lt;pointer&gt;</tt>' operand must be a pointer to
4361 the <a href="#t_firstclass">first class</a> type of the
Jeffrey Yasskin5d284ae2010-04-26 21:21:24 +0000[diff] [blame]4362 '<tt>&lt;value&gt;</tt>' operand. If the <tt>store</tt> is marked as
4363 <tt>volatile</tt>, then the optimizer is not allowed to modify the number or
4364 order of execution of this <tt>store</tt> with other <a
4365 href="#volatile">volatile operations</a>.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4366
4367<p>The optional constant "align" argument specifies the alignment of the
4368 operation (that is, the alignment of the memory address). A value of 0 or an
4369 omitted "align" argument means that the operation has the preferential
4370 alignment for the target. It is the responsibility of the code emitter to
4371 ensure that the alignment information is correct. Overestimating the
4372 alignment results in an undefined behavior. Underestimating the alignment may
4373 produce less efficient code. An alignment of 1 is always safe.</p>
4374
David Greene9641d062010-02-16 20:50:18 +0000[diff] [blame]4375<p>The optional !nontemporal metadata must reference a single metatadata
4376 name <index> corresponding to a metadata node with one i32 entry of
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]4377 value 1. The existence of the !nontemporal metatadata on the
David Greene9641d062010-02-16 20:50:18 +0000[diff] [blame]4378 instruction tells the optimizer and code generator that this load is
4379 not expected to be reused in the cache. The code generator may
4380 select special instructions to save cache bandwidth, such as the
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]4381 MOVNT instruction on x86.</p>
David Greene9641d062010-02-16 20:50:18 +0000[diff] [blame]4382
4383
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]4384<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4385<p>The contents of memory are updated to contain '<tt>&lt;value&gt;</tt>' at the
4386 location specified by the '<tt>&lt;pointer&gt;</tt>' operand. If
4387 '<tt>&lt;value&gt;</tt>' is of scalar type then the number of bytes written
4388 does not exceed the minimum number of bytes needed to hold all bits of the
4389 type. For example, storing an <tt>i24</tt> writes at most three bytes. When
4390 writing a value of a type like <tt>i20</tt> with a size that is not an
4391 integral number of bytes, it is unspecified what happens to the extra bits
4392 that do not belong to the type, but they will typically be overwritten.</p>
4393
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4394<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4395<pre>
4396 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Bill Wendling8830ffe2007-10-22 05:10:05 +0000[diff] [blame]4397 store i32 3, i32* %ptr <i>; yields {void}</i>
4398 %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]4399</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4400
Reid Spencer443460a2006-11-09 21:15:49 +0000[diff] [blame]4401</div>
4402
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4403<!-- _______________________________________________________________________ -->
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4404<div class="doc_subsubsection">
4405 <a name="i_getelementptr">'<tt>getelementptr</tt>' Instruction</a>
4406</div>
4407
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4408<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4409
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]4410<h5>Syntax:</h5>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4411<pre>
Matthijs Kooijman0e268272008-10-13 13:44:15 +0000[diff] [blame]4412 &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]4413 &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]4414</pre>
4415
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]4416<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4417<p>The '<tt>getelementptr</tt>' instruction is used to get the address of a
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]4418 subelement of an <a href="#t_aggregate">aggregate</a> data structure.
4419 It performs address calculation only and does not access memory.</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4420
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]4421<h5>Arguments:</h5>
Matthijs Kooijman0e268272008-10-13 13:44:15 +0000[diff] [blame]4422<p>The first argument is always a pointer, and forms the basis of the
Chris Lattnera40b9122009-07-29 06:44:13 +0000[diff] [blame]4423 calculation. The remaining arguments are indices that indicate which of the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4424 elements of the aggregate object are indexed. The interpretation of each
4425 index is dependent on the type being indexed into. The first index always
4426 indexes the pointer value given as the first argument, the second index
4427 indexes a value of the type pointed to (not necessarily the value directly
4428 pointed to, since the first index can be non-zero), etc. The first type
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]4429 indexed into must be a pointer value, subsequent types can be arrays,
4430 vectors, structs and unions. Note that subsequent types being indexed into
4431 can never be pointers, since that would require loading the pointer before
4432 continuing calculation.</p>
Matthijs Kooijman0e268272008-10-13 13:44:15 +0000[diff] [blame]4433
4434<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]4435 When indexing into a (optionally packed) structure or union, only <tt>i32</tt>
4436 integer <b>constants</b> are allowed. When indexing into an array, pointer
4437 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]4438 constant.</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4439
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4440<p>For example, let's consider a C code fragment and how it gets compiled to
4441 LLVM:</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4442
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]4443<div class="doc_code">
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4444<pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]4445struct RT {
4446 char A;
Chris Lattnera446f1b2007-05-29 15:43:56 +0000[diff] [blame]4447 int B[10][20];
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]4448 char C;
4449};
4450struct ST {
Chris Lattnera446f1b2007-05-29 15:43:56 +0000[diff] [blame]4451 int X;
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]4452 double Y;
4453 struct RT Z;
4454};
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4455
Chris Lattnera446f1b2007-05-29 15:43:56 +0000[diff] [blame]4456int *foo(struct ST *s) {
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]4457 return &amp;s[1].Z.B[5][13];
4458}
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4459</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]4460</div>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4461
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4462<p>The LLVM code generated by the GCC frontend is:</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4463
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]4464<div class="doc_code">
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4465<pre>
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]4466%RT = <a href="#namedtypes">type</a> { i8 , [10 x [20 x i32]], i8 }
4467%ST = <a href="#namedtypes">type</a> { i32, double, %RT }
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4468
Dan Gohman6b867702009-07-25 02:23:48 +0000[diff] [blame]4469define i32* @foo(%ST* %s) {
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]4470entry:
4471 %reg = getelementptr %ST* %s, i32 1, i32 2, i32 1, i32 5, i32 13
4472 ret i32* %reg
4473}
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4474</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]4475</div>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4476
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]4477<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4478<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]4479 type, which is a pointer, yielding a '<tt>%ST</tt>' = '<tt>{ i32, double, %RT
4480 }</tt>' type, a structure. The second index indexes into the third element
4481 of the structure, yielding a '<tt>%RT</tt>' = '<tt>{ i8 , [10 x [20 x i32]],
4482 i8 }</tt>' type, another structure. The third index indexes into the second
4483 element of the structure, yielding a '<tt>[10 x [20 x i32]]</tt>' type, an
4484 array. The two dimensions of the array are subscripted into, yielding an
4485 '<tt>i32</tt>' type. The '<tt>getelementptr</tt>' instruction returns a
4486 pointer to this element, thus computing a value of '<tt>i32*</tt>' type.</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4487
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4488<p>Note that it is perfectly legal to index partially through a structure,
4489 returning a pointer to an inner element. Because of this, the LLVM code for
4490 the given testcase is equivalent to:</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4491
4492<pre>
Dan Gohman6b867702009-07-25 02:23:48 +0000[diff] [blame]4493 define i32* @foo(%ST* %s) {
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4494 %t1 = getelementptr %ST* %s, i32 1 <i>; yields %ST*:%t1</i>
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]4495 %t2 = getelementptr %ST* %t1, i32 0, i32 2 <i>; yields %RT*:%t2</i>
4496 %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]4497 %t4 = getelementptr [10 x [20 x i32]]* %t3, i32 0, i32 5 <i>; yields [20 x i32]*:%t4</i>
4498 %t5 = getelementptr [20 x i32]* %t4, i32 0, i32 13 <i>; yields i32*:%t5</i>
4499 ret i32* %t5
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4500 }
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]4501</pre>
Chris Lattnerc0ad71e2005-06-24 17:22:57 +0000[diff] [blame]4502
Dan Gohman1639c392009-07-27 21:53:46 +0000[diff] [blame]4503<p>If the <tt>inbounds</tt> keyword is present, the result value of the
Dan Gohman57255802010-04-23 15:23:32 +0000[diff] [blame]4504 <tt>getelementptr</tt> is a <a href="#trapvalues">trap value</a> if the
4505 base pointer is not an <i>in bounds</i> address of an allocated object,
4506 or if any of the addresses that would be formed by successive addition of
4507 the offsets implied by the indices to the base address with infinitely
4508 precise arithmetic are not an <i>in bounds</i> address of that allocated
4509 object. The <i>in bounds</i> addresses for an allocated object are all
4510 the addresses that point into the object, plus the address one byte past
4511 the end.</p>
Dan Gohman1639c392009-07-27 21:53:46 +0000[diff] [blame]4512
4513<p>If the <tt>inbounds</tt> keyword is not present, the offsets are added to
4514 the base address with silently-wrapping two's complement arithmetic, and
4515 the result value of the <tt>getelementptr</tt> may be outside the object
4516 pointed to by the base pointer. The result value may not necessarily be
4517 used to access memory though, even if it happens to point into allocated
4518 storage. See the <a href="#pointeraliasing">Pointer Aliasing Rules</a>
4519 section for more information.</p>
4520
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4521<p>The getelementptr instruction is often confusing. For some more insight into
4522 how it works, see <a href="GetElementPtr.html">the getelementptr FAQ</a>.</p>
Chris Lattner6ab66722006-08-15 00:45:58 +0000[diff] [blame]4523
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]4524<h5>Example:</h5>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4525<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4526 <i>; yields [12 x i8]*:aptr</i>
Matthijs Kooijman0e268272008-10-13 13:44:15 +0000[diff] [blame]4527 %aptr = getelementptr {i32, [12 x i8]}* %saptr, i64 0, i32 1
4528 <i>; yields i8*:vptr</i>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]4529 %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]4530 <i>; yields i8*:eptr</i>
4531 %eptr = getelementptr [12 x i8]* %aptr, i64 0, i32 1
Sanjiv Gupta0c155e62009-04-25 07:27:44 +0000[diff] [blame]4532 <i>; yields i32*:iptr</i>
Sanjiv Gupta77abea02009-04-24 16:38:13 +0000[diff] [blame]4533 %iptr = getelementptr [10 x i32]* @arr, i16 0, i16 0
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4534</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4535
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4536</div>
Reid Spencer443460a2006-11-09 21:15:49 +0000[diff] [blame]4537
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4538<!-- ======================================================================= -->
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]4539<div class="doc_subsection"> <a name="convertops">Conversion Operations</a>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4540</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4541
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4542<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4543
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]4544<p>The instructions in this category are the conversion instructions (casting)
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4545 which all take a single operand and a type. They perform various bit
4546 conversions on the operand.</p>
4547
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4548</div>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]4549
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]4550<!-- _______________________________________________________________________ -->
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]4551<div class="doc_subsubsection">
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4552 <a name="i_trunc">'<tt>trunc .. to</tt>' Instruction</a>
4553</div>
4554<div class="doc_text">
4555
4556<h5>Syntax:</h5>
4557<pre>
4558 &lt;result&gt; = trunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4559</pre>
4560
4561<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4562<p>The '<tt>trunc</tt>' instruction truncates its operand to the
4563 type <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4564
4565<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4566<p>The '<tt>trunc</tt>' instruction takes a <tt>value</tt> to trunc, which must
4567 be an <a href="#t_integer">integer</a> type, and a type that specifies the
4568 size and type of the result, which must be
4569 an <a href="#t_integer">integer</a> type. The bit size of <tt>value</tt> must
4570 be larger than the bit size of <tt>ty2</tt>. Equal sized types are not
4571 allowed.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4572
4573<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4574<p>The '<tt>trunc</tt>' instruction truncates the high order bits
4575 in <tt>value</tt> and converts the remaining bits to <tt>ty2</tt>. Since the
4576 source size must be larger than the destination size, <tt>trunc</tt> cannot
4577 be a <i>no-op cast</i>. It will always truncate bits.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4578
4579<h5>Example:</h5>
4580<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4581 %X = trunc i32 257 to i8 <i>; yields i8:1</i>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]4582 %Y = trunc i32 123 to i1 <i>; yields i1:true</i>
Gabor Greiff50fd572009-10-28 09:21:30 +0000[diff] [blame]4583 %Z = trunc i32 122 to i1 <i>; yields i1:false</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4584</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4585
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4586</div>
4587
4588<!-- _______________________________________________________________________ -->
4589<div class="doc_subsubsection">
4590 <a name="i_zext">'<tt>zext .. to</tt>' Instruction</a>
4591</div>
4592<div class="doc_text">
4593
4594<h5>Syntax:</h5>
4595<pre>
4596 &lt;result&gt; = zext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4597</pre>
4598
4599<h5>Overview:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4600<p>The '<tt>zext</tt>' instruction zero extends its operand to type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4601 <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4602
4603
4604<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4605<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]4606 <a href="#t_integer">integer</a> type, and a type to cast it to, which must
4607 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]4608 <tt>value</tt> must be smaller than the bit size of the destination type,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4609 <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4610
4611<h5>Semantics:</h5>
4612<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]4613 bits until it reaches the size of the destination type, <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4614
Reid Spencer07c9c682007-01-12 15:46:11 +0000[diff] [blame]4615<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]4616
4617<h5>Example:</h5>
4618<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4619 %X = zext i32 257 to i64 <i>; yields i64:257</i>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]4620 %Y = zext i1 true to i32 <i>; yields i32:1</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4621</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4622
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4623</div>
4624
4625<!-- _______________________________________________________________________ -->
4626<div class="doc_subsubsection">
4627 <a name="i_sext">'<tt>sext .. to</tt>' Instruction</a>
4628</div>
4629<div class="doc_text">
4630
4631<h5>Syntax:</h5>
4632<pre>
4633 &lt;result&gt; = sext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4634</pre>
4635
4636<h5>Overview:</h5>
4637<p>The '<tt>sext</tt>' sign extends <tt>value</tt> to the type <tt>ty2</tt>.</p>
4638
4639<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4640<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]4641 <a href="#t_integer">integer</a> type, and a type to cast it to, which must
4642 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]4643 <tt>value</tt> must be smaller than the bit size of the destination type,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4644 <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4645
4646<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4647<p>The '<tt>sext</tt>' instruction performs a sign extension by copying the sign
4648 bit (highest order bit) of the <tt>value</tt> until it reaches the bit size
4649 of the type <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4650
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]4651<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]4652
4653<h5>Example:</h5>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4654<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4655 %X = sext i8 -1 to i16 <i>; yields i16 :65535</i>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]4656 %Y = sext i1 true to i32 <i>; yields i32:-1</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4657</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4658
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4659</div>
4660
4661<!-- _______________________________________________________________________ -->
4662<div class="doc_subsubsection">
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]4663 <a name="i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a>
4664</div>
4665
4666<div class="doc_text">
4667
4668<h5>Syntax:</h5>
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]4669<pre>
4670 &lt;result&gt; = fptrunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4671</pre>
4672
4673<h5>Overview:</h5>
4674<p>The '<tt>fptrunc</tt>' instruction truncates <tt>value</tt> to type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4675 <tt>ty2</tt>.</p>
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]4676
4677<h5>Arguments:</h5>
4678<p>The '<tt>fptrunc</tt>' instruction takes a <a href="#t_floating">floating
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4679 point</a> value to cast and a <a href="#t_floating">floating point</a> type
4680 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]4681 <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]4682 <i>no-op cast</i>.</p>
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]4683
4684<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4685<p>The '<tt>fptrunc</tt>' instruction truncates a <tt>value</tt> from a larger
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4686 <a href="#t_floating">floating point</a> type to a smaller
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4687 <a href="#t_floating">floating point</a> type. If the value cannot fit
4688 within the destination type, <tt>ty2</tt>, then the results are
4689 undefined.</p>
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]4690
4691<h5>Example:</h5>
4692<pre>
4693 %X = fptrunc double 123.0 to float <i>; yields float:123.0</i>
4694 %Y = fptrunc double 1.0E+300 to float <i>; yields undefined</i>
4695</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4696
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]4697</div>
4698
4699<!-- _______________________________________________________________________ -->
4700<div class="doc_subsubsection">
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4701 <a name="i_fpext">'<tt>fpext .. to</tt>' Instruction</a>
4702</div>
4703<div class="doc_text">
4704
4705<h5>Syntax:</h5>
4706<pre>
4707 &lt;result&gt; = fpext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4708</pre>
4709
4710<h5>Overview:</h5>
4711<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]4712 floating point value.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4713
4714<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4715<p>The '<tt>fpext</tt>' instruction takes a
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4716 <a href="#t_floating">floating point</a> <tt>value</tt> to cast, and
4717 a <a href="#t_floating">floating point</a> type to cast it to. The source
4718 type must be smaller than the destination type.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4719
4720<h5>Semantics:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]4721<p>The '<tt>fpext</tt>' instruction extends the <tt>value</tt> from a smaller
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4722 <a href="#t_floating">floating point</a> type to a larger
4723 <a href="#t_floating">floating point</a> type. The <tt>fpext</tt> cannot be
4724 used to make a <i>no-op cast</i> because it always changes bits. Use
4725 <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]4726
4727<h5>Example:</h5>
4728<pre>
4729 %X = fpext float 3.1415 to double <i>; yields double:3.1415</i>
4730 %Y = fpext float 1.0 to float <i>; yields float:1.0 (no-op)</i>
4731</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4732
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4733</div>
4734
4735<!-- _______________________________________________________________________ -->
4736<div class="doc_subsubsection">
Reid Spencer2eadb532007-01-21 00:29:26 +0000[diff] [blame]4737 <a name="i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4738</div>
4739<div class="doc_text">
4740
4741<h5>Syntax:</h5>
4742<pre>
Reid Spencer753163d2007-07-31 14:40:14 +0000[diff] [blame]4743 &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]4744</pre>
4745
4746<h5>Overview:</h5>
Reid Spencer753163d2007-07-31 14:40:14 +0000[diff] [blame]4747<p>The '<tt>fptoui</tt>' converts a floating point <tt>value</tt> to its
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4748 unsigned integer equivalent of type <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4749
4750<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4751<p>The '<tt>fptoui</tt>' instruction takes a value to cast, which must be a
4752 scalar or vector <a href="#t_floating">floating point</a> value, and a type
4753 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
4754 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
4755 vector integer type with the same number of elements as <tt>ty</tt></p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4756
4757<h5>Semantics:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4758<p>The '<tt>fptoui</tt>' instruction converts its
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4759 <a href="#t_floating">floating point</a> operand into the nearest (rounding
4760 towards zero) unsigned integer value. If the value cannot fit
4761 in <tt>ty2</tt>, the results are undefined.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4762
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4763<h5>Example:</h5>
4764<pre>
Reid Spencer753163d2007-07-31 14:40:14 +0000[diff] [blame]4765 %X = fptoui double 123.0 to i32 <i>; yields i32:123</i>
Chris Lattner5b95a172007-09-22 03:17:52 +0000[diff] [blame]4766 %Y = fptoui float 1.0E+300 to i1 <i>; yields undefined:1</i>
Gabor Greiff50fd572009-10-28 09:21:30 +0000[diff] [blame]4767 %Z = fptoui float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4768</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4769
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4770</div>
4771
4772<!-- _______________________________________________________________________ -->
4773<div class="doc_subsubsection">
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]4774 <a name="i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4775</div>
4776<div class="doc_text">
4777
4778<h5>Syntax:</h5>
4779<pre>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]4780 &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]4781</pre>
4782
4783<h5>Overview:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4784<p>The '<tt>fptosi</tt>' instruction converts
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4785 <a href="#t_floating">floating point</a> <tt>value</tt> to
4786 type <tt>ty2</tt>.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]4787
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]4788<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4789<p>The '<tt>fptosi</tt>' instruction takes a value to cast, which must be a
4790 scalar or vector <a href="#t_floating">floating point</a> value, and a type
4791 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
4792 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
4793 vector integer type with the same number of elements as <tt>ty</tt></p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]4794
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]4795<h5>Semantics:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4796<p>The '<tt>fptosi</tt>' instruction converts its
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4797 <a href="#t_floating">floating point</a> operand into the nearest (rounding
4798 towards zero) signed integer value. If the value cannot fit in <tt>ty2</tt>,
4799 the results are undefined.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]4800
Chris Lattner70de6632001-07-09 00:26:23 +0000[diff] [blame]4801<h5>Example:</h5>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]4802<pre>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]4803 %X = fptosi double -123.0 to i32 <i>; yields i32:-123</i>
Chris Lattner5b95a172007-09-22 03:17:52 +0000[diff] [blame]4804 %Y = fptosi float 1.0E-247 to i1 <i>; yields undefined:1</i>
Gabor Greiff50fd572009-10-28 09:21:30 +0000[diff] [blame]4805 %Z = fptosi float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4806</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4807
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4808</div>
4809
4810<!-- _______________________________________________________________________ -->
4811<div class="doc_subsubsection">
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]4812 <a name="i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4813</div>
4814<div class="doc_text">
4815
4816<h5>Syntax:</h5>
4817<pre>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]4818 &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]4819</pre>
4820
4821<h5>Overview:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]4822<p>The '<tt>uitofp</tt>' instruction regards <tt>value</tt> as an unsigned
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4823 integer and converts that value to the <tt>ty2</tt> type.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4824
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4825<h5>Arguments:</h5>
Nate Begemand4d45c22007-11-17 03:58:34 +0000[diff] [blame]4826<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]4827 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
4828 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
4829 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
4830 floating point type with the same number of elements as <tt>ty</tt></p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4831
4832<h5>Semantics:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]4833<p>The '<tt>uitofp</tt>' instruction interprets its operand as an unsigned
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4834 integer quantity and converts it to the corresponding floating point
4835 value. If the value cannot fit in the floating point value, the results are
4836 undefined.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4837
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4838<h5>Example:</h5>
4839<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4840 %X = uitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]4841 %Y = uitofp i8 -1 to double <i>; yields double:255.0</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4842</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4843
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4844</div>
4845
4846<!-- _______________________________________________________________________ -->
4847<div class="doc_subsubsection">
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]4848 <a name="i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4849</div>
4850<div class="doc_text">
4851
4852<h5>Syntax:</h5>
4853<pre>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]4854 &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]4855</pre>
4856
4857<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4858<p>The '<tt>sitofp</tt>' instruction regards <tt>value</tt> as a signed integer
4859 and converts that value to the <tt>ty2</tt> type.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4860
4861<h5>Arguments:</h5>
Nate Begemand4d45c22007-11-17 03:58:34 +0000[diff] [blame]4862<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]4863 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
4864 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
4865 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
4866 floating point type with the same number of elements as <tt>ty</tt></p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4867
4868<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4869<p>The '<tt>sitofp</tt>' instruction interprets its operand as a signed integer
4870 quantity and converts it to the corresponding floating point value. If the
4871 value cannot fit in the floating point value, the results are undefined.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4872
4873<h5>Example:</h5>
4874<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4875 %X = sitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]4876 %Y = sitofp i8 -1 to double <i>; yields double:-1.0</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4877</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4878
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4879</div>
4880
4881<!-- _______________________________________________________________________ -->
4882<div class="doc_subsubsection">
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]4883 <a name="i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a>
4884</div>
4885<div class="doc_text">
4886
4887<h5>Syntax:</h5>
4888<pre>
4889 &lt;result&gt; = ptrtoint &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4890</pre>
4891
4892<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4893<p>The '<tt>ptrtoint</tt>' instruction converts the pointer <tt>value</tt> to
4894 the integer type <tt>ty2</tt>.</p>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]4895
4896<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4897<p>The '<tt>ptrtoint</tt>' instruction takes a <tt>value</tt> to cast, which
4898 must be a <a href="#t_pointer">pointer</a> value, and a type to cast it to
4899 <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]4900
4901<h5>Semantics:</h5>
4902<p>The '<tt>ptrtoint</tt>' instruction converts <tt>value</tt> to integer type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4903 <tt>ty2</tt> by interpreting the pointer value as an integer and either
4904 truncating or zero extending that value to the size of the integer type. If
4905 <tt>value</tt> is smaller than <tt>ty2</tt> then a zero extension is done. If
4906 <tt>value</tt> is larger than <tt>ty2</tt> then a truncation is done. If they
4907 are the same size, then nothing is done (<i>no-op cast</i>) other than a type
4908 change.</p>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]4909
4910<h5>Example:</h5>
4911<pre>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]4912 %X = ptrtoint i32* %X to i8 <i>; yields truncation on 32-bit architecture</i>
4913 %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]4914</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4915
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]4916</div>
4917
4918<!-- _______________________________________________________________________ -->
4919<div class="doc_subsubsection">
4920 <a name="i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a>
4921</div>
4922<div class="doc_text">
4923
4924<h5>Syntax:</h5>
4925<pre>
4926 &lt;result&gt; = inttoptr &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4927</pre>
4928
4929<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4930<p>The '<tt>inttoptr</tt>' instruction converts an integer <tt>value</tt> to a
4931 pointer type, <tt>ty2</tt>.</p>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]4932
4933<h5>Arguments:</h5>
Duncan Sands16f122e2007-03-30 12:22:09 +0000[diff] [blame]4934<p>The '<tt>inttoptr</tt>' instruction takes an <a href="#t_integer">integer</a>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4935 value to cast, and a type to cast it to, which must be a
4936 <a href="#t_pointer">pointer</a> type.</p>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]4937
4938<h5>Semantics:</h5>
4939<p>The '<tt>inttoptr</tt>' instruction converts <tt>value</tt> to type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4940 <tt>ty2</tt> by applying either a zero extension or a truncation depending on
4941 the size of the integer <tt>value</tt>. If <tt>value</tt> is larger than the
4942 size of a pointer then a truncation is done. If <tt>value</tt> is smaller
4943 than the size of a pointer then a zero extension is done. If they are the
4944 same size, nothing is done (<i>no-op cast</i>).</p>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]4945
4946<h5>Example:</h5>
4947<pre>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]4948 %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]4949 %Y = inttoptr i32 255 to i32* <i>; yields no-op on 32-bit architecture</i>
4950 %Z = inttoptr i64 0 to i32* <i>; yields truncation on 32-bit architecture</i>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]4951</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4952
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]4953</div>
4954
4955<!-- _______________________________________________________________________ -->
4956<div class="doc_subsubsection">
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]4957 <a name="i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4958</div>
4959<div class="doc_text">
4960
4961<h5>Syntax:</h5>
4962<pre>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]4963 &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]4964</pre>
4965
4966<h5>Overview:</h5>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]4967<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4968 <tt>ty2</tt> without changing any bits.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4969
4970<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4971<p>The '<tt>bitcast</tt>' instruction takes a value to cast, which must be a
4972 non-aggregate first class value, and a type to cast it to, which must also be
4973 a non-aggregate <a href="#t_firstclass">first class</a> type. The bit sizes
4974 of <tt>value</tt> and the destination type, <tt>ty2</tt>, must be
4975 identical. If the source type is a pointer, the destination type must also be
4976 a pointer. This instruction supports bitwise conversion of vectors to
4977 integers and to vectors of other types (as long as they have the same
4978 size).</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4979
4980<h5>Semantics:</h5>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]4981<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4982 <tt>ty2</tt>. It is always a <i>no-op cast</i> because no bits change with
4983 this conversion. The conversion is done as if the <tt>value</tt> had been
4984 stored to memory and read back as type <tt>ty2</tt>. Pointer types may only
4985 be converted to other pointer types with this instruction. To convert
4986 pointers to other types, use the <a href="#i_inttoptr">inttoptr</a> or
4987 <a href="#i_ptrtoint">ptrtoint</a> instructions first.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4988
4989<h5>Example:</h5>
4990<pre>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]4991 %X = bitcast i8 255 to i8 <i>; yields i8 :-1</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4992 %Y = bitcast i32* %x to sint* <i>; yields sint*:%x</i>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4993 %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]4994</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4995
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4996</div>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]4997
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]4998<!-- ======================================================================= -->
4999<div class="doc_subsection"> <a name="otherops">Other Operations</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5000
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5001<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5002
5003<p>The instructions in this category are the "miscellaneous" instructions, which
5004 defy better classification.</p>
5005
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5006</div>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5007
5008<!-- _______________________________________________________________________ -->
5009<div class="doc_subsubsection"><a name="i_icmp">'<tt>icmp</tt>' Instruction</a>
5010</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5011
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5012<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5013
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5014<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5015<pre>
5016 &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]5017</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5018
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5019<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5020<p>The '<tt>icmp</tt>' instruction returns a boolean value or a vector of
5021 boolean values based on comparison of its two integer, integer vector, or
5022 pointer operands.</p>
5023
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5024<h5>Arguments:</h5>
5025<p>The '<tt>icmp</tt>' instruction takes three operands. The first operand is
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5026 the condition code indicating the kind of comparison to perform. It is not a
5027 value, just a keyword. The possible condition code are:</p>
5028
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5029<ol>
5030 <li><tt>eq</tt>: equal</li>
5031 <li><tt>ne</tt>: not equal </li>
5032 <li><tt>ugt</tt>: unsigned greater than</li>
5033 <li><tt>uge</tt>: unsigned greater or equal</li>
5034 <li><tt>ult</tt>: unsigned less than</li>
5035 <li><tt>ule</tt>: unsigned less or equal</li>
5036 <li><tt>sgt</tt>: signed greater than</li>
5037 <li><tt>sge</tt>: signed greater or equal</li>
5038 <li><tt>slt</tt>: signed less than</li>
5039 <li><tt>sle</tt>: signed less or equal</li>
5040</ol>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5041
Chris Lattnerc0f423a2007-01-15 01:54:13 +0000[diff] [blame]5042<p>The remaining two arguments must be <a href="#t_integer">integer</a> or
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5043 <a href="#t_pointer">pointer</a> or integer <a href="#t_vector">vector</a>
5044 typed. They must also be identical types.</p>
5045
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5046<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5047<p>The '<tt>icmp</tt>' compares <tt>op1</tt> and <tt>op2</tt> according to the
5048 condition code given as <tt>cond</tt>. The comparison performed always yields
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]5049 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]5050 result, as follows:</p>
5051
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5052<ol>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5053 <li><tt>eq</tt>: yields <tt>true</tt> if the operands are equal,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5054 <tt>false</tt> otherwise. No sign interpretation is necessary or
5055 performed.</li>
5056
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5057 <li><tt>ne</tt>: yields <tt>true</tt> if the operands are unequal,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5058 <tt>false</tt> otherwise. No sign interpretation is necessary or
5059 performed.</li>
5060
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5061 <li><tt>ugt</tt>: interprets the operands as unsigned values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5062 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
5063
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5064 <li><tt>uge</tt>: interprets the operands as unsigned values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5065 <tt>true</tt> if <tt>op1</tt> is greater than or equal
5066 to <tt>op2</tt>.</li>
5067
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5068 <li><tt>ult</tt>: interprets the operands as unsigned values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5069 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
5070
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5071 <li><tt>ule</tt>: interprets the operands as unsigned values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5072 <tt>true</tt> if <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
5073
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5074 <li><tt>sgt</tt>: interprets the operands as signed values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5075 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
5076
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5077 <li><tt>sge</tt>: interprets the operands as signed values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5078 <tt>true</tt> if <tt>op1</tt> is greater than or equal
5079 to <tt>op2</tt>.</li>
5080
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5081 <li><tt>slt</tt>: interprets the operands as signed values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5082 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
5083
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5084 <li><tt>sle</tt>: interprets the operands as signed values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5085 <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]5086</ol>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5087
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5088<p>If the operands are <a href="#t_pointer">pointer</a> typed, the pointer
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5089 values are compared as if they were integers.</p>
5090
5091<p>If the operands are integer vectors, then they are compared element by
5092 element. The result is an <tt>i1</tt> vector with the same number of elements
5093 as the values being compared. Otherwise, the result is an <tt>i1</tt>.</p>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5094
5095<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5096<pre>
5097 &lt;result&gt; = icmp eq i32 4, 5 <i>; yields: result=false</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]5098 &lt;result&gt; = icmp ne float* %X, %X <i>; yields: result=false</i>
5099 &lt;result&gt; = icmp ult i16 4, 5 <i>; yields: result=true</i>
5100 &lt;result&gt; = icmp sgt i16 4, 5 <i>; yields: result=false</i>
5101 &lt;result&gt; = icmp ule i16 -4, 5 <i>; yields: result=false</i>
5102 &lt;result&gt; = icmp sge i16 4, 5 <i>; yields: result=false</i>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5103</pre>
Dan Gohmana5127ab2009-01-22 01:39:38 +0000[diff] [blame]5104
5105<p>Note that the code generator does not yet support vector types with
5106 the <tt>icmp</tt> instruction.</p>
5107
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5108</div>
5109
5110<!-- _______________________________________________________________________ -->
5111<div class="doc_subsubsection"><a name="i_fcmp">'<tt>fcmp</tt>' Instruction</a>
5112</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5113
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5114<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5115
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5116<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5117<pre>
5118 &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]5119</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5120
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5121<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5122<p>The '<tt>fcmp</tt>' instruction returns a boolean value or vector of boolean
5123 values based on comparison of its operands.</p>
5124
5125<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]5126(<a href="#t_integer"><tt>i1</tt></a>).</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5127
5128<p>If the operands are floating point vectors, then the result type is a vector
5129 of boolean with the same number of elements as the operands being
5130 compared.</p>
5131
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5132<h5>Arguments:</h5>
5133<p>The '<tt>fcmp</tt>' instruction takes three operands. The first operand is
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5134 the condition code indicating the kind of comparison to perform. It is not a
5135 value, just a keyword. The possible condition code are:</p>
5136
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5137<ol>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]5138 <li><tt>false</tt>: no comparison, always returns false</li>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5139 <li><tt>oeq</tt>: ordered and equal</li>
5140 <li><tt>ogt</tt>: ordered and greater than </li>
5141 <li><tt>oge</tt>: ordered and greater than or equal</li>
5142 <li><tt>olt</tt>: ordered and less than </li>
5143 <li><tt>ole</tt>: ordered and less than or equal</li>
5144 <li><tt>one</tt>: ordered and not equal</li>
5145 <li><tt>ord</tt>: ordered (no nans)</li>
5146 <li><tt>ueq</tt>: unordered or equal</li>
5147 <li><tt>ugt</tt>: unordered or greater than </li>
5148 <li><tt>uge</tt>: unordered or greater than or equal</li>
5149 <li><tt>ult</tt>: unordered or less than </li>
5150 <li><tt>ule</tt>: unordered or less than or equal</li>
5151 <li><tt>une</tt>: unordered or not equal</li>
5152 <li><tt>uno</tt>: unordered (either nans)</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]5153 <li><tt>true</tt>: no comparison, always returns true</li>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5154</ol>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5155
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5156<p><i>Ordered</i> means that neither operand is a QNAN while
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5157 <i>unordered</i> means that either operand may be a QNAN.</p>
5158
5159<p>Each of <tt>val1</tt> and <tt>val2</tt> arguments must be either
5160 a <a href="#t_floating">floating point</a> type or
5161 a <a href="#t_vector">vector</a> of floating point type. They must have
5162 identical types.</p>
5163
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5164<h5>Semantics:</h5>
Gabor Greif0f75ad02008-08-07 21:46:00 +0000[diff] [blame]5165<p>The '<tt>fcmp</tt>' instruction compares <tt>op1</tt> and <tt>op2</tt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5166 according to the condition code given as <tt>cond</tt>. If the operands are
5167 vectors, then the vectors are compared element by element. Each comparison
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]5168 performed always yields an <a href="#t_integer">i1</a> result, as
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5169 follows:</p>
5170
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5171<ol>
5172 <li><tt>false</tt>: always yields <tt>false</tt>, regardless of operands.</li>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5173
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5174 <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]5175 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
5176
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]5177 <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]5178 <tt>op1</tt> is greater than <tt>op2</tt>.</li>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5179
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5180 <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]5181 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
5182
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5183 <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]5184 <tt>op1</tt> is less than <tt>op2</tt>.</li>
5185
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5186 <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]5187 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
5188
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5189 <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]5190 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
5191
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]5192 <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]5193
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5194 <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]5195 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
5196
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5197 <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]5198 <tt>op1</tt> is greater than <tt>op2</tt>.</li>
5199
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5200 <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]5201 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
5202
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5203 <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]5204 <tt>op1</tt> is less than <tt>op2</tt>.</li>
5205
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5206 <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]5207 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
5208
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5209 <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]5210 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
5211
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]5212 <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]5213
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5214 <li><tt>true</tt>: always yields <tt>true</tt>, regardless of operands.</li>
5215</ol>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5216
5217<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5218<pre>
5219 &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]5220 &lt;result&gt; = fcmp one float 4.0, 5.0 <i>; yields: result=true</i>
5221 &lt;result&gt; = fcmp olt float 4.0, 5.0 <i>; yields: result=true</i>
5222 &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]5223</pre>
Dan Gohmana5127ab2009-01-22 01:39:38 +0000[diff] [blame]5224
5225<p>Note that the code generator does not yet support vector types with
5226 the <tt>fcmp</tt> instruction.</p>
5227
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5228</div>
5229
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5230<!-- _______________________________________________________________________ -->
Nate Begemand2195702008-05-12 19:01:56 +0000[diff] [blame]5231<div class="doc_subsubsection">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]5232 <a name="i_phi">'<tt>phi</tt>' Instruction</a>
5233</div>
5234
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5235<div class="doc_text">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]5236
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5237<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5238<pre>
5239 &lt;result&gt; = phi &lt;ty&gt; [ &lt;val0&gt;, &lt;label0&gt;], ...
5240</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]5241
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5242<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5243<p>The '<tt>phi</tt>' instruction is used to implement the &#966; node in the
5244 SSA graph representing the function.</p>
5245
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5246<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5247<p>The type of the incoming values is specified with the first type field. After
5248 this, the '<tt>phi</tt>' instruction takes a list of pairs as arguments, with
5249 one pair for each predecessor basic block of the current block. Only values
5250 of <a href="#t_firstclass">first class</a> type may be used as the value
5251 arguments to the PHI node. Only labels may be used as the label
5252 arguments.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]5253
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5254<p>There must be no non-phi instructions between the start of a basic block and
5255 the PHI instructions: i.e. PHI instructions must be first in a basic
5256 block.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]5257
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5258<p>For the purposes of the SSA form, the use of each incoming value is deemed to
5259 occur on the edge from the corresponding predecessor block to the current
5260 block (but after any definition of an '<tt>invoke</tt>' instruction's return
5261 value on the same edge).</p>
Jay Foad1a4eea52009-06-03 10:20:10 +0000[diff] [blame]5262
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5263<h5>Semantics:</h5>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5264<p>At runtime, the '<tt>phi</tt>' instruction logically takes on the value
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5265 specified by the pair corresponding to the predecessor basic block that
5266 executed just prior to the current block.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]5267
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5268<h5>Example:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]5269<pre>
5270Loop: ; Infinite loop that counts from 0 on up...
5271 %indvar = phi i32 [ 0, %LoopHeader ], [ %nextindvar, %Loop ]
5272 %nextindvar = add i32 %indvar, 1
5273 br label %Loop
5274</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5275
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5276</div>
5277
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5278<!-- _______________________________________________________________________ -->
5279<div class="doc_subsubsection">
5280 <a name="i_select">'<tt>select</tt>' Instruction</a>
5281</div>
5282
5283<div class="doc_text">
5284
5285<h5>Syntax:</h5>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5286<pre>
Dan Gohmanc579d972008-09-09 01:02:47 +0000[diff] [blame]5287 &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>
5288
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]5289 <i>selty</i> is either i1 or {&lt;N x i1&gt;}
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5290</pre>
5291
5292<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5293<p>The '<tt>select</tt>' instruction is used to choose one value based on a
5294 condition, without branching.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5295
5296
5297<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5298<p>The '<tt>select</tt>' instruction requires an 'i1' value or a vector of 'i1'
5299 values indicating the condition, and two values of the
5300 same <a href="#t_firstclass">first class</a> type. If the val1/val2 are
5301 vectors and the condition is a scalar, then entire vectors are selected, not
5302 individual elements.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5303
5304<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5305<p>If the condition is an i1 and it evaluates to 1, the instruction returns the
5306 first value argument; otherwise, it returns the second value argument.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5307
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5308<p>If the condition is a vector of i1, then the value arguments must be vectors
5309 of the same size, and the selection is done element by element.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5310
5311<h5>Example:</h5>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5312<pre>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]5313 %X = select i1 true, i8 17, i8 42 <i>; yields i8:17</i>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5314</pre>
Dan Gohmana5127ab2009-01-22 01:39:38 +0000[diff] [blame]5315
5316<p>Note that the code generator does not yet support conditions
5317 with vector type.</p>
5318
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5319</div>
5320
Robert Bocchinof72fdfe2006-01-15 20:48:27 +0000[diff] [blame]5321<!-- _______________________________________________________________________ -->
5322<div class="doc_subsubsection">
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5323 <a name="i_call">'<tt>call</tt>' Instruction</a>
5324</div>
5325
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5326<div class="doc_text">
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5327
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]5328<h5>Syntax:</h5>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5329<pre>
Devang Patel02256232008-10-07 17:48:33 +0000[diff] [blame]5330 &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]5331</pre>
5332
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]5333<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5334<p>The '<tt>call</tt>' instruction represents a simple function call.</p>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5335
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]5336<h5>Arguments:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5337<p>This instruction requires several arguments:</p>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5338
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]5339<ol>
Jeffrey Yasskinb8677462010-01-09 19:44:16 +0000[diff] [blame]5340 <li>The optional "tail" marker indicates that the callee function does not
5341 access any allocas or varargs in the caller. Note that calls may be
5342 marked "tail" even if they do not occur before
5343 a <a href="#i_ret"><tt>ret</tt></a> instruction. If the "tail" marker is
5344 present, the function call is eligible for tail call optimization,
5345 but <a href="CodeGenerator.html#tailcallopt">might not in fact be
Evan Cheng59676492010-03-08 21:05:02 +0000[diff] [blame]5346 optimized into a jump</a>. The code generator may optimize calls marked
5347 "tail" with either 1) automatic <a href="CodeGenerator.html#sibcallopt">
5348 sibling call optimization</a> when the caller and callee have
5349 matching signatures, or 2) forced tail call optimization when the
5350 following extra requirements are met:
Jeffrey Yasskinb8677462010-01-09 19:44:16 +0000[diff] [blame]5351 <ul>
5352 <li>Caller and callee both have the calling
5353 convention <tt>fastcc</tt>.</li>
5354 <li>The call is in tail position (ret immediately follows call and ret
5355 uses value of call or is void).</li>
5356 <li>Option <tt>-tailcallopt</tt> is enabled,
Dan Gohman6232f732010-03-02 01:08:11 +0000[diff] [blame]5357 or <code>llvm::GuaranteedTailCallOpt</code> is <code>true</code>.</li>
Jeffrey Yasskinb8677462010-01-09 19:44:16 +0000[diff] [blame]5358 <li><a href="CodeGenerator.html#tailcallopt">Platform specific
5359 constraints are met.</a></li>
5360 </ul>
5361 </li>
Devang Patel7e9b05e2008-10-06 18:50:38 +0000[diff] [blame]5362
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5363 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
5364 convention</a> the call should use. If none is specified, the call
Jeffrey Yasskinb8677462010-01-09 19:44:16 +0000[diff] [blame]5365 defaults to using C calling conventions. The calling convention of the
5366 call must match the calling convention of the target function, or else the
5367 behavior is undefined.</li>
Devang Patel7e9b05e2008-10-06 18:50:38 +0000[diff] [blame]5368
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5369 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
5370 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
5371 '<tt>inreg</tt>' attributes are valid here.</li>
5372
5373 <li>'<tt>ty</tt>': the type of the call instruction itself which is also the
5374 type of the return value. Functions that return no value are marked
5375 <tt><a href="#t_void">void</a></tt>.</li>
5376
5377 <li>'<tt>fnty</tt>': shall be the signature of the pointer to function value
5378 being invoked. The argument types must match the types implied by this
5379 signature. This type can be omitted if the function is not varargs and if
5380 the function type does not return a pointer to a function.</li>
5381
5382 <li>'<tt>fnptrval</tt>': An LLVM value containing a pointer to a function to
5383 be invoked. In most cases, this is a direct function invocation, but
5384 indirect <tt>call</tt>s are just as possible, calling an arbitrary pointer
5385 to function value.</li>
5386
5387 <li>'<tt>function args</tt>': argument list whose types match the function
Chris Lattner47f2a832010-03-02 06:36:51 +0000[diff] [blame]5388 signature argument types and parameter attributes. All arguments must be
5389 of <a href="#t_firstclass">first class</a> type. If the function
5390 signature indicates the function accepts a variable number of arguments,
5391 the extra arguments can be specified.</li>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5392
5393 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
5394 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
5395 '<tt>readnone</tt>' attributes are valid here.</li>
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]5396</ol>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5397
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]5398<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5399<p>The '<tt>call</tt>' instruction is used to cause control flow to transfer to
5400 a specified function, with its incoming arguments bound to the specified
5401 values. Upon a '<tt><a href="#i_ret">ret</a></tt>' instruction in the called
5402 function, control flow continues with the instruction after the function
5403 call, and the return value of the function is bound to the result
5404 argument.</p>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5405
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]5406<h5>Example:</h5>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5407<pre>
Nick Lewyckya9b13d52007-09-08 13:57:50 +0000[diff] [blame]5408 %retval = call i32 @test(i32 %argc)
Chris Lattnerfb7c88d2008-03-21 17:24:17 +0000[diff] [blame]5409 call i32 (i8 *, ...)* @printf(i8 * %msg, i32 12, i8 42) <i>; yields i32</i>
5410 %X = tail call i32 @foo() <i>; yields i32</i>
5411 %Y = tail call <a href="#callingconv">fastcc</a> i32 @foo() <i>; yields i32</i>
5412 call void %foo(i8 97 signext)
Devang Pateld6cff512008-03-10 20:49:15 +0000[diff] [blame]5413
5414 %struct.A = type { i32, i8 }
Devang Patel7e9b05e2008-10-06 18:50:38 +0000[diff] [blame]5415 %r = call %struct.A @foo() <i>; yields { 32, i8 }</i>
Dan Gohmancc3132e2008-10-04 19:00:07 +0000[diff] [blame]5416 %gr = extractvalue %struct.A %r, 0 <i>; yields i32</i>
5417 %gr1 = extractvalue %struct.A %r, 1 <i>; yields i8</i>
Chris Lattner6cbe8e92008-10-08 06:26:11 +0000[diff] [blame]5418 %Z = call void @foo() noreturn <i>; indicates that %foo never returns normally</i>
Matthijs Kooijmaneefa7df2008-10-07 10:03:45 +0000[diff] [blame]5419 %ZZ = call zeroext i32 @bar() <i>; Return value is %zero extended</i>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5420</pre>
5421
Dale Johannesen68f971b2009-09-24 18:38:21 +0000[diff] [blame]5422<p>llvm treats calls to some functions with names and arguments that match the
Dale Johannesen722212d2009-09-25 17:04:42 +0000[diff] [blame]5423standard C99 library as being the C99 library functions, and may perform
5424optimizations or generate code for them under that assumption. This is
5425something we'd like to change in the future to provide better support for
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]5426freestanding environments and non-C-based languages.</p>
Dale Johannesen68f971b2009-09-24 18:38:21 +0000[diff] [blame]5427
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5428</div>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5429
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5430<!-- _______________________________________________________________________ -->
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5431<div class="doc_subsubsection">
Chris Lattner33337472006-01-13 23:26:01 +0000[diff] [blame]5432 <a name="i_va_arg">'<tt>va_arg</tt>' Instruction</a>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5433</div>
5434
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5435<div class="doc_text">
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5436
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]5437<h5>Syntax:</h5>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5438<pre>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]5439 &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]5440</pre>
5441
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]5442<h5>Overview:</h5>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]5443<p>The '<tt>va_arg</tt>' instruction is used to access arguments passed through
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5444 the "variable argument" area of a function call. It is used to implement the
5445 <tt>va_arg</tt> macro in C.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5446
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]5447<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5448<p>This instruction takes a <tt>va_list*</tt> value and the type of the
5449 argument. It returns a value of the specified argument type and increments
5450 the <tt>va_list</tt> to point to the next argument. The actual type
5451 of <tt>va_list</tt> is target specific.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5452
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]5453<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5454<p>The '<tt>va_arg</tt>' instruction loads an argument of the specified type
5455 from the specified <tt>va_list</tt> and causes the <tt>va_list</tt> to point
5456 to the next argument. For more information, see the variable argument
5457 handling <a href="#int_varargs">Intrinsic Functions</a>.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5458
5459<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]5460 take a variable number of arguments, for example, the <tt>vfprintf</tt>
5461 function.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5462
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5463<p><tt>va_arg</tt> is an LLVM instruction instead of
5464 an <a href="#intrinsics">intrinsic function</a> because it takes a type as an
5465 argument.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5466
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]5467<h5>Example:</h5>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5468<p>See the <a href="#int_varargs">variable argument processing</a> section.</p>
5469
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5470<p>Note that the code generator does not yet fully support va_arg on many
5471 targets. Also, it does not currently support va_arg with aggregate types on
5472 any target.</p>
Dan Gohman3065b612009-01-12 23:12:39 +0000[diff] [blame]5473
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5474</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5475
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5476<!-- *********************************************************************** -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]5477<div class="doc_section"> <a name="intrinsics">Intrinsic Functions</a> </div>
5478<!-- *********************************************************************** -->
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5479
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5480<div class="doc_text">
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5481
5482<p>LLVM supports the notion of an "intrinsic function". These functions have
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5483 well known names and semantics and are required to follow certain
5484 restrictions. Overall, these intrinsics represent an extension mechanism for
5485 the LLVM language that does not require changing all of the transformations
5486 in LLVM when adding to the language (or the bitcode reader/writer, the
5487 parser, etc...).</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5488
John Criswell88190562005-05-16 16:17:45 +0000[diff] [blame]5489<p>Intrinsic function names must all start with an "<tt>llvm.</tt>" prefix. This
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5490 prefix is reserved in LLVM for intrinsic names; thus, function names may not
5491 begin with this prefix. Intrinsic functions must always be external
5492 functions: you cannot define the body of intrinsic functions. Intrinsic
5493 functions may only be used in call or invoke instructions: it is illegal to
5494 take the address of an intrinsic function. Additionally, because intrinsic
5495 functions are part of the LLVM language, it is required if any are added that
5496 they be documented here.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5497
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5498<p>Some intrinsic functions can be overloaded, i.e., the intrinsic represents a
5499 family of functions that perform the same operation but on different data
5500 types. Because LLVM can represent over 8 million different integer types,
5501 overloading is used commonly to allow an intrinsic function to operate on any
5502 integer type. One or more of the argument types or the result type can be
5503 overloaded to accept any integer type. Argument types may also be defined as
5504 exactly matching a previous argument's type or the result type. This allows
5505 an intrinsic function which accepts multiple arguments, but needs all of them
5506 to be of the same type, to only be overloaded with respect to a single
5507 argument or the result.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5508
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5509<p>Overloaded intrinsics will have the names of its overloaded argument types
5510 encoded into its function name, each preceded by a period. Only those types
5511 which are overloaded result in a name suffix. Arguments whose type is matched
5512 against another type do not. For example, the <tt>llvm.ctpop</tt> function
5513 can take an integer of any width and returns an integer of exactly the same
5514 integer width. This leads to a family of functions such as
5515 <tt>i8 @llvm.ctpop.i8(i8 %val)</tt> and <tt>i29 @llvm.ctpop.i29(i29
5516 %val)</tt>. Only one type, the return type, is overloaded, and only one type
5517 suffix is required. Because the argument's type is matched against the return
5518 type, it does not require its own name suffix.</p>
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]5519
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5520<p>To learn how to add an intrinsic function, please see the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5521 <a href="ExtendingLLVM.html">Extending LLVM Guide</a>.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5522
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5523</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5524
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5525<!-- ======================================================================= -->
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5526<div class="doc_subsection">
5527 <a name="int_varargs">Variable Argument Handling Intrinsics</a>
5528</div>
5529
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5530<div class="doc_text">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5531
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5532<p>Variable argument support is defined in LLVM with
5533 the <a href="#i_va_arg"><tt>va_arg</tt></a> instruction and these three
5534 intrinsic functions. These functions are related to the similarly named
5535 macros defined in the <tt>&lt;stdarg.h&gt;</tt> header file.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5536
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5537<p>All of these functions operate on arguments that use a target-specific value
5538 type "<tt>va_list</tt>". The LLVM assembly language reference manual does
5539 not define what this type is, so all transformations should be prepared to
5540 handle these functions regardless of the type used.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5541
Chris Lattner30b868d2006-05-15 17:26:46 +0000[diff] [blame]5542<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]5543 instruction and the variable argument handling intrinsic functions are
5544 used.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5545
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]5546<div class="doc_code">
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5547<pre>
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]5548define i32 @test(i32 %X, ...) {
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5549 ; Initialize variable argument processing
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5550 %ap = alloca i8*
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]5551 %ap2 = bitcast i8** %ap to i8*
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]5552 call void @llvm.va_start(i8* %ap2)
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5553
5554 ; Read a single integer argument
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5555 %tmp = va_arg i8** %ap, i32
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5556
5557 ; Demonstrate usage of llvm.va_copy and llvm.va_end
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5558 %aq = alloca i8*
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]5559 %aq2 = bitcast i8** %aq to i8*
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5560 call void @llvm.va_copy(i8* %aq2, i8* %ap2)
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]5561 call void @llvm.va_end(i8* %aq2)
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5562
5563 ; Stop processing of arguments.
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]5564 call void @llvm.va_end(i8* %ap2)
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]5565 ret i32 %tmp
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5566}
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]5567
5568declare void @llvm.va_start(i8*)
5569declare void @llvm.va_copy(i8*, i8*)
5570declare void @llvm.va_end(i8*)
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5571</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5572</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5573
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]5574</div>
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_start">'<tt>llvm.va_start</tt>' Intrinsic</a>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5579</div>
5580
5581
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5582<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5583
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5584<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5585<pre>
5586 declare void %llvm.va_start(i8* &lt;arglist&gt;)
5587</pre>
5588
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5589<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5590<p>The '<tt>llvm.va_start</tt>' intrinsic initializes <tt>*&lt;arglist&gt;</tt>
5591 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]5592
5593<h5>Arguments:</h5>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]5594<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]5595
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5596<h5>Semantics:</h5>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]5597<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]5598 macro available in C. In a target-dependent way, it initializes
5599 the <tt>va_list</tt> element to which the argument points, so that the next
5600 call to <tt>va_arg</tt> will produce the first variable argument passed to
5601 the function. Unlike the C <tt>va_start</tt> macro, this intrinsic does not
5602 need to know the last argument of the function as the compiler can figure
5603 that out.</p>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +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_end">'<tt>llvm.va_end</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 Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]5613
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5614<h5>Syntax:</h5>
5615<pre>
5616 declare void @llvm.va_end(i8* &lt;arglist&gt;)
5617</pre>
5618
5619<h5>Overview:</h5>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5620<p>The '<tt>llvm.va_end</tt>' intrinsic destroys <tt>*&lt;arglist&gt;</tt>,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5621 which has been initialized previously
5622 with <tt><a href="#int_va_start">llvm.va_start</a></tt>
5623 or <tt><a href="#i_va_copy">llvm.va_copy</a></tt>.</p>
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]5624
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5625<h5>Arguments:</h5>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5626<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]5627
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5628<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5629<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]5630 macro available in C. In a target-dependent way, it destroys
5631 the <tt>va_list</tt> element to which the argument points. Calls
5632 to <a href="#int_va_start"><tt>llvm.va_start</tt></a>
5633 and <a href="#int_va_copy"> <tt>llvm.va_copy</tt></a> must be matched exactly
5634 with calls to <tt>llvm.va_end</tt>.</p>
Chris Lattnerdb0790c2007-01-08 07:55:15 +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 Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5638<!-- _______________________________________________________________________ -->
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5639<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5640 <a name="int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5641</div>
5642
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5643<div class="doc_text">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5644
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5645<h5>Syntax:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5646<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]5647 declare void @llvm.va_copy(i8* &lt;destarglist&gt;, i8* &lt;srcarglist&gt;)
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5648</pre>
5649
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5650<h5>Overview:</h5>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5651<p>The '<tt>llvm.va_copy</tt>' intrinsic copies the current argument position
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5652 from the source argument list to the destination argument list.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5653
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5654<h5>Arguments:</h5>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]5655<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]5656 The second argument is a pointer to a <tt>va_list</tt> element to copy
5657 from.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5658
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5659<h5>Semantics:</h5>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5660<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]5661 macro available in C. In a target-dependent way, it copies the
5662 source <tt>va_list</tt> element into the destination <tt>va_list</tt>
5663 element. This intrinsic is necessary because
5664 the <tt><a href="#int_va_start"> llvm.va_start</a></tt> intrinsic may be
5665 arbitrarily complex and require, for example, memory allocation.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5666
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5667</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5668
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5669<!-- ======================================================================= -->
5670<div class="doc_subsection">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5671 <a name="int_gc">Accurate Garbage Collection Intrinsics</a>
5672</div>
5673
5674<div class="doc_text">
5675
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5676<p>LLVM support for <a href="GarbageCollection.html">Accurate Garbage
Chris Lattner67c37d12008-08-05 18:29:16 +0000[diff] [blame]5677Collection</a> (GC) requires the implementation and generation of these
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5678intrinsics. These intrinsics allow identification of <a href="#int_gcroot">GC
5679roots on the stack</a>, as well as garbage collector implementations that
5680require <a href="#int_gcread">read</a> and <a href="#int_gcwrite">write</a>
5681barriers. Front-ends for type-safe garbage collected languages should generate
5682these intrinsics to make use of the LLVM garbage collectors. For more details,
5683see <a href="GarbageCollection.html">Accurate Garbage Collection with
5684LLVM</a>.</p>
Christopher Lamb55c6d4f2007-12-17 01:00:21 +0000[diff] [blame]5685
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5686<p>The garbage collection intrinsics only operate on objects in the generic
5687 address space (address space zero).</p>
Christopher Lamb55c6d4f2007-12-17 01:00:21 +0000[diff] [blame]5688
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5689</div>
5690
5691<!-- _______________________________________________________________________ -->
5692<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5693 <a name="int_gcroot">'<tt>llvm.gcroot</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 void @llvm.gcroot(i8** %ptrloc, i8* %metadata)
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5701</pre>
5702
5703<h5>Overview:</h5>
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]5704<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]5705 the code generator, and allows some metadata to be associated with it.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5706
5707<h5>Arguments:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5708<p>The first argument specifies the address of a stack object that contains the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5709 root pointer. The second pointer (which must be either a constant or a
5710 global value address) contains the meta-data to be associated with the
5711 root.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5712
5713<h5>Semantics:</h5>
Chris Lattner851b7712008-04-24 05:59:56 +0000[diff] [blame]5714<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]5715 location. At compile-time, the code generator generates information to allow
5716 the runtime to find the pointer at GC safe points. The '<tt>llvm.gcroot</tt>'
5717 intrinsic may only be used in a function which <a href="#gc">specifies a GC
5718 algorithm</a>.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5719
5720</div>
5721
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5722<!-- _______________________________________________________________________ -->
5723<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5724 <a name="int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5725</div>
5726
5727<div class="doc_text">
5728
5729<h5>Syntax:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5730<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]5731 declare i8* @llvm.gcread(i8* %ObjPtr, i8** %Ptr)
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5732</pre>
5733
5734<h5>Overview:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5735<p>The '<tt>llvm.gcread</tt>' intrinsic identifies reads of references from heap
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5736 locations, allowing garbage collector implementations that require read
5737 barriers.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5738
5739<h5>Arguments:</h5>
Chris Lattnerf9228072006-03-14 20:02:51 +0000[diff] [blame]5740<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]5741 allocated from the garbage collector. The first object is a pointer to the
5742 start of the referenced object, if needed by the language runtime (otherwise
5743 null).</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5744
5745<h5>Semantics:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5746<p>The '<tt>llvm.gcread</tt>' intrinsic has the same semantics as a load
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5747 instruction, but may be replaced with substantially more complex code by the
5748 garbage collector runtime, as needed. The '<tt>llvm.gcread</tt>' intrinsic
5749 may only be used in a function which <a href="#gc">specifies a GC
5750 algorithm</a>.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5751
5752</div>
5753
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5754<!-- _______________________________________________________________________ -->
5755<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5756 <a name="int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5757</div>
5758
5759<div class="doc_text">
5760
5761<h5>Syntax:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5762<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]5763 declare void @llvm.gcwrite(i8* %P1, i8* %Obj, i8** %P2)
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5764</pre>
5765
5766<h5>Overview:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5767<p>The '<tt>llvm.gcwrite</tt>' intrinsic identifies writes of references to heap
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5768 locations, allowing garbage collector implementations that require write
5769 barriers (such as generational or reference counting collectors).</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5770
5771<h5>Arguments:</h5>
Chris Lattnerf9228072006-03-14 20:02:51 +0000[diff] [blame]5772<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]5773 object to store it to, and the third is the address of the field of Obj to
5774 store to. If the runtime does not require a pointer to the object, Obj may
5775 be null.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5776
5777<h5>Semantics:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5778<p>The '<tt>llvm.gcwrite</tt>' intrinsic has the same semantics as a store
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5779 instruction, but may be replaced with substantially more complex code by the
5780 garbage collector runtime, as needed. The '<tt>llvm.gcwrite</tt>' intrinsic
5781 may only be used in a function which <a href="#gc">specifies a GC
5782 algorithm</a>.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5783
5784</div>
5785
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5786<!-- ======================================================================= -->
5787<div class="doc_subsection">
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5788 <a name="int_codegen">Code Generator Intrinsics</a>
5789</div>
5790
5791<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5792
5793<p>These intrinsics are provided by LLVM to expose special features that may
5794 only be implemented with code generator support.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5795
5796</div>
5797
5798<!-- _______________________________________________________________________ -->
5799<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5800 <a name="int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5801</div>
5802
5803<div class="doc_text">
5804
5805<h5>Syntax:</h5>
5806<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]5807 declare i8 *@llvm.returnaddress(i32 &lt;level&gt;)
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5808</pre>
5809
5810<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5811<p>The '<tt>llvm.returnaddress</tt>' intrinsic attempts to compute a
5812 target-specific value indicating the return address of the current function
5813 or one of its callers.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5814
5815<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5816<p>The argument to this intrinsic indicates which function to return the address
5817 for. Zero indicates the calling function, one indicates its caller, etc.
5818 The argument is <b>required</b> to be a constant integer value.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5819
5820<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5821<p>The '<tt>llvm.returnaddress</tt>' intrinsic either returns a pointer
5822 indicating the return address of the specified call frame, or zero if it
5823 cannot be identified. The value returned by this intrinsic is likely to be
5824 incorrect or 0 for arguments other than zero, so it should only be used for
5825 debugging purposes.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5826
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5827<p>Note that calling this intrinsic does not prevent function inlining or other
5828 aggressive transformations, so the value returned may not be that of the
5829 obvious source-language caller.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5830
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5831</div>
5832
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5833<!-- _______________________________________________________________________ -->
5834<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5835 <a name="int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5836</div>
5837
5838<div class="doc_text">
5839
5840<h5>Syntax:</h5>
5841<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]5842 declare i8 *@llvm.frameaddress(i32 &lt;level&gt;)
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5843</pre>
5844
5845<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5846<p>The '<tt>llvm.frameaddress</tt>' intrinsic attempts to return the
5847 target-specific frame pointer value for the specified stack frame.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5848
5849<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5850<p>The argument to this intrinsic indicates which function to return the frame
5851 pointer for. Zero indicates the calling function, one indicates its caller,
5852 etc. The argument is <b>required</b> to be a constant integer value.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5853
5854<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5855<p>The '<tt>llvm.frameaddress</tt>' intrinsic either returns a pointer
5856 indicating the frame address of the specified call frame, or zero if it
5857 cannot be identified. The value returned by this intrinsic is likely to be
5858 incorrect or 0 for arguments other than zero, so it should only be used for
5859 debugging purposes.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5860
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5861<p>Note that calling this intrinsic does not prevent function inlining or other
5862 aggressive transformations, so the value returned may not be that of the
5863 obvious source-language caller.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5864
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5865</div>
5866
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]5867<!-- _______________________________________________________________________ -->
5868<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5869 <a name="int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]5870</div>
5871
5872<div class="doc_text">
5873
5874<h5>Syntax:</h5>
5875<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]5876 declare i8 *@llvm.stacksave()
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]5877</pre>
5878
5879<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5880<p>The '<tt>llvm.stacksave</tt>' intrinsic is used to remember the current state
5881 of the function stack, for use
5882 with <a href="#int_stackrestore"> <tt>llvm.stackrestore</tt></a>. This is
5883 useful for implementing language features like scoped automatic variable
5884 sized arrays in C99.</p>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]5885
5886<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5887<p>This intrinsic returns a opaque pointer value that can be passed
5888 to <a href="#int_stackrestore"><tt>llvm.stackrestore</tt></a>. When
5889 an <tt>llvm.stackrestore</tt> intrinsic is executed with a value saved
5890 from <tt>llvm.stacksave</tt>, it effectively restores the state of the stack
5891 to the state it was in when the <tt>llvm.stacksave</tt> intrinsic executed.
5892 In practice, this pops any <a href="#i_alloca">alloca</a> blocks from the
5893 stack that were allocated after the <tt>llvm.stacksave</tt> was executed.</p>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]5894
5895</div>
5896
5897<!-- _______________________________________________________________________ -->
5898<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5899 <a name="int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]5900</div>
5901
5902<div class="doc_text">
5903
5904<h5>Syntax:</h5>
5905<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]5906 declare void @llvm.stackrestore(i8 * %ptr)
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]5907</pre>
5908
5909<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5910<p>The '<tt>llvm.stackrestore</tt>' intrinsic is used to restore the state of
5911 the function stack to the state it was in when the
5912 corresponding <a href="#int_stacksave"><tt>llvm.stacksave</tt></a> intrinsic
5913 executed. This is useful for implementing language features like scoped
5914 automatic variable sized arrays in C99.</p>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]5915
5916<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5917<p>See the description
5918 for <a href="#int_stacksave"><tt>llvm.stacksave</tt></a>.</p>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]5919
5920</div>
5921
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]5922<!-- _______________________________________________________________________ -->
5923<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5924 <a name="int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a>
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]5925</div>
5926
5927<div class="doc_text">
5928
5929<h5>Syntax:</h5>
5930<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]5931 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]5932</pre>
5933
5934<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5935<p>The '<tt>llvm.prefetch</tt>' intrinsic is a hint to the code generator to
5936 insert a prefetch instruction if supported; otherwise, it is a noop.
5937 Prefetches have no effect on the behavior of the program but can change its
5938 performance characteristics.</p>
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]5939
5940<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5941<p><tt>address</tt> is the address to be prefetched, <tt>rw</tt> is the
5942 specifier determining if the fetch should be for a read (0) or write (1),
5943 and <tt>locality</tt> is a temporal locality specifier ranging from (0) - no
5944 locality, to (3) - extremely local keep in cache. The <tt>rw</tt>
5945 and <tt>locality</tt> arguments must be constant integers.</p>
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]5946
5947<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5948<p>This intrinsic does not modify the behavior of the program. In particular,
5949 prefetches cannot trap and do not produce a value. On targets that support
5950 this intrinsic, the prefetch can provide hints to the processor cache for
5951 better performance.</p>
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]5952
5953</div>
5954
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]5955<!-- _______________________________________________________________________ -->
5956<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5957 <a name="int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a>
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]5958</div>
5959
5960<div class="doc_text">
5961
5962<h5>Syntax:</h5>
5963<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]5964 declare void @llvm.pcmarker(i32 &lt;id&gt;)
Andrew Lenharthb4427912005-03-28 20:05:49 +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.pcmarker</tt>' intrinsic is a method to export a Program
5969 Counter (PC) in a region of code to simulators and other tools. The method
5970 is target specific, but it is expected that the marker will use exported
5971 symbols to transmit the PC of the marker. The marker makes no guarantees
5972 that it will remain with any specific instruction after optimizations. It is
5973 possible that the presence of a marker will inhibit optimizations. The
5974 intended use is to be inserted after optimizations to allow correlations of
5975 simulation runs.</p>
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]5976
5977<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5978<p><tt>id</tt> is a numerical id identifying the marker.</p>
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]5979
5980<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5981<p>This intrinsic does not modify the behavior of the program. Backends that do
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]5982 not support this intrinsic may ignore it.</p>
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]5983
5984</div>
5985
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]5986<!-- _______________________________________________________________________ -->
5987<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5988 <a name="int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a>
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]5989</div>
5990
5991<div class="doc_text">
5992
5993<h5>Syntax:</h5>
5994<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]5995 declare i64 @llvm.readcyclecounter( )
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]5996</pre>
5997
5998<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5999<p>The '<tt>llvm.readcyclecounter</tt>' intrinsic provides access to the cycle
6000 counter register (or similar low latency, high accuracy clocks) on those
6001 targets that support it. On X86, it should map to RDTSC. On Alpha, it
6002 should map to RPCC. As the backing counters overflow quickly (on the order
6003 of 9 seconds on alpha), this should only be used for small timings.</p>
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]6004
6005<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6006<p>When directly supported, reading the cycle counter should not modify any
6007 memory. Implementations are allowed to either return a application specific
6008 value or a system wide value. On backends without support, this is lowered
6009 to a constant 0.</p>
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]6010
6011</div>
6012
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6013<!-- ======================================================================= -->
6014<div class="doc_subsection">
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6015 <a name="int_libc">Standard C Library Intrinsics</a>
6016</div>
6017
6018<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6019
6020<p>LLVM provides intrinsics for a few important standard C library functions.
6021 These intrinsics allow source-language front-ends to pass information about
6022 the alignment of the pointer arguments to the code generator, providing
6023 opportunity for more efficient code generation.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6024
6025</div>
6026
6027<!-- _______________________________________________________________________ -->
6028<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6029 <a name="int_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6030</div>
6031
6032<div class="doc_text">
6033
6034<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6035<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]6036 integer bit width and for different address spaces. Not all targets support
6037 all bit widths however.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6038
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6039<pre>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6040 declare void @llvm.memcpy.p0i8.p0i8.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
6041 i32 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
6042 declare void @llvm.memcpy.p0i8.p0i8.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
6043 i64 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6044</pre>
6045
6046<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6047<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
6048 source location to the destination location.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6049
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6050<p>Note that, unlike the standard libc function, the <tt>llvm.memcpy.*</tt>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6051 intrinsics do not return a value, takes extra alignment/isvolatile arguments
6052 and the pointers can be in specified address spaces.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6053
6054<h5>Arguments:</h5>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6055
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6056<p>The first argument is a pointer to the destination, the second is a pointer
6057 to the source. The third argument is an integer argument specifying the
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6058 number of bytes to copy, the fourth argument is the alignment of the
6059 source and destination locations, and the fifth is a boolean indicating a
6060 volatile access.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6061
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]6062<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]6063 then the caller guarantees that both the source and destination pointers are
6064 aligned to that boundary.</p>
Chris Lattner4c67c482004-02-12 21:18:15 +0000[diff] [blame]6065
Jeffrey Yasskin5d284ae2010-04-26 21:21:24 +0000[diff] [blame]6066<p>If the <tt>isvolatile</tt> parameter is <tt>true</tt>, the
6067 <tt>llvm.memcpy</tt> call is a <a href="#volatile">volatile operation</a>.
6068 The detailed access behavior is not very cleanly specified and it is unwise
6069 to depend on it.</p>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6070
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6071<h5>Semantics:</h5>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6072
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6073<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
6074 source location to the destination location, which are not allowed to
6075 overlap. It copies "len" bytes of memory over. If the argument is known to
6076 be aligned to some boundary, this can be specified as the fourth argument,
6077 otherwise it should be set to 0 or 1.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6078
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6079</div>
6080
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6081<!-- _______________________________________________________________________ -->
6082<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6083 <a name="int_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a>
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6084</div>
6085
6086<div class="doc_text">
6087
6088<h5>Syntax:</h5>
Chris Lattnerdd708342008-11-21 16:42:48 +0000[diff] [blame]6089<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]6090 width and for different address space. Not all targets support all bit
6091 widths however.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6092
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6093<pre>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6094 declare void @llvm.memmove.p0i8.p0i8.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
6095 i32 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
6096 declare void @llvm.memmove.p0i8.p0i8.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
6097 i64 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6098</pre>
6099
6100<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6101<p>The '<tt>llvm.memmove.*</tt>' intrinsics move a block of memory from the
6102 source location to the destination location. It is similar to the
6103 '<tt>llvm.memcpy</tt>' intrinsic but allows the two memory locations to
6104 overlap.</p>
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6105
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6106<p>Note that, unlike the standard libc function, the <tt>llvm.memmove.*</tt>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6107 intrinsics do not return a value, takes extra alignment/isvolatile arguments
6108 and the pointers can be in specified address spaces.</p>
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6109
6110<h5>Arguments:</h5>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6111
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6112<p>The first argument is a pointer to the destination, the second is a pointer
6113 to the source. The third argument is an integer argument specifying the
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6114 number of bytes to copy, the fourth argument is the alignment of the
6115 source and destination locations, and the fifth is a boolean indicating a
6116 volatile access.</p>
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6117
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]6118<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]6119 then the caller guarantees that the source and destination pointers are
6120 aligned to that boundary.</p>
Chris Lattner4c67c482004-02-12 21:18:15 +0000[diff] [blame]6121
Jeffrey Yasskin5d284ae2010-04-26 21:21:24 +0000[diff] [blame]6122<p>If the <tt>isvolatile</tt> parameter is <tt>true</tt>, the
6123 <tt>llvm.memmove</tt> call is a <a href="#volatile">volatile operation</a>.
6124 The detailed access behavior is not very cleanly specified and it is unwise
6125 to depend on it.</p>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6126
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6127<h5>Semantics:</h5>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6128
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6129<p>The '<tt>llvm.memmove.*</tt>' intrinsics copy a block of memory from the
6130 source location to the destination location, which may overlap. It copies
6131 "len" bytes of memory over. If the argument is known to be aligned to some
6132 boundary, this can be specified as the fourth argument, otherwise it should
6133 be set to 0 or 1.</p>
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6134
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6135</div>
6136
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6137<!-- _______________________________________________________________________ -->
6138<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6139 <a name="int_memset">'<tt>llvm.memset.*</tt>' Intrinsics</a>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6140</div>
6141
6142<div class="doc_text">
6143
6144<h5>Syntax:</h5>
Chris Lattnerdd708342008-11-21 16:42:48 +0000[diff] [blame]6145<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]6146 width and for different address spaces. Not all targets support all bit
6147 widths however.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6148
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6149<pre>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6150 declare void @llvm.memset.p0i8.i32(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
Chris Lattner685db9d2010-04-08 00:54:34 +0000[diff] [blame]6151 i32 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6152 declare void @llvm.memset.p0i8.i64(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
Chris Lattner685db9d2010-04-08 00:54:34 +0000[diff] [blame]6153 i64 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6154</pre>
6155
6156<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6157<p>The '<tt>llvm.memset.*</tt>' intrinsics fill a block of memory with a
6158 particular byte value.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6159
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6160<p>Note that, unlike the standard libc function, the <tt>llvm.memset</tt>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6161 intrinsic does not return a value, takes extra alignment/volatile arguments,
6162 and the destination can be in an arbitrary address space.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6163
6164<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6165<p>The first argument is a pointer to the destination to fill, the second is the
6166 byte value to fill it with, the third argument is an integer argument
6167 specifying the number of bytes to fill, and the fourth argument is the known
6168 alignment of destination location.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6169
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]6170<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]6171 then the caller guarantees that the destination pointer is aligned to that
6172 boundary.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6173
Jeffrey Yasskin5d284ae2010-04-26 21:21:24 +0000[diff] [blame]6174<p>If the <tt>isvolatile</tt> parameter is <tt>true</tt>, the
6175 <tt>llvm.memset</tt> call is a <a href="#volatile">volatile operation</a>.
6176 The detailed access behavior is not very cleanly specified and it is unwise
6177 to depend on it.</p>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6178
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6179<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6180<p>The '<tt>llvm.memset.*</tt>' intrinsics fill "len" bytes of memory starting
6181 at the destination location. If the argument is known to be aligned to some
6182 boundary, this can be specified as the fourth argument, otherwise it should
6183 be set to 0 or 1.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6184
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6185</div>
6186
Chris Lattner3b4f4372004-06-11 02:28:03 +0000[diff] [blame]6187<!-- _______________________________________________________________________ -->
6188<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6189 <a name="int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a>
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]6190</div>
6191
6192<div class="doc_text">
6193
6194<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6195<p>This is an overloaded intrinsic. You can use <tt>llvm.sqrt</tt> on any
6196 floating point or vector of floating point type. Not all targets support all
6197 types however.</p>
6198
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]6199<pre>
Dale Johannesendd89d272007-10-02 17:47:38 +0000[diff] [blame]6200 declare float @llvm.sqrt.f32(float %Val)
6201 declare double @llvm.sqrt.f64(double %Val)
6202 declare x86_fp80 @llvm.sqrt.f80(x86_fp80 %Val)
6203 declare fp128 @llvm.sqrt.f128(fp128 %Val)
6204 declare ppc_fp128 @llvm.sqrt.ppcf128(ppc_fp128 %Val)
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]6205</pre>
6206
6207<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6208<p>The '<tt>llvm.sqrt</tt>' intrinsics return the sqrt of the specified operand,
6209 returning the same value as the libm '<tt>sqrt</tt>' functions would.
6210 Unlike <tt>sqrt</tt> in libm, however, <tt>llvm.sqrt</tt> has undefined
6211 behavior for negative numbers other than -0.0 (which allows for better
6212 optimization, because there is no need to worry about errno being
6213 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]6214
6215<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6216<p>The argument and return value are floating point numbers of the same
6217 type.</p>
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]6218
6219<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6220<p>This function returns the sqrt of the specified operand if it is a
6221 nonnegative floating point number.</p>
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]6222
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]6223</div>
6224
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]6225<!-- _______________________________________________________________________ -->
6226<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6227 <a name="int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a>
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]6228</div>
6229
6230<div class="doc_text">
6231
6232<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6233<p>This is an overloaded intrinsic. You can use <tt>llvm.powi</tt> on any
6234 floating point or vector of floating point type. Not all targets support all
6235 types however.</p>
6236
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]6237<pre>
Dale Johannesendd89d272007-10-02 17:47:38 +0000[diff] [blame]6238 declare float @llvm.powi.f32(float %Val, i32 %power)
6239 declare double @llvm.powi.f64(double %Val, i32 %power)
6240 declare x86_fp80 @llvm.powi.f80(x86_fp80 %Val, i32 %power)
6241 declare fp128 @llvm.powi.f128(fp128 %Val, i32 %power)
6242 declare ppc_fp128 @llvm.powi.ppcf128(ppc_fp128 %Val, i32 %power)
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]6243</pre>
6244
6245<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6246<p>The '<tt>llvm.powi.*</tt>' intrinsics return the first operand raised to the
6247 specified (positive or negative) power. The order of evaluation of
6248 multiplications is not defined. When a vector of floating point type is
6249 used, the second argument remains a scalar integer value.</p>
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]6250
6251<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6252<p>The second argument is an integer power, and the first is a value to raise to
6253 that power.</p>
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]6254
6255<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6256<p>This function returns the first value raised to the second power with an
6257 unspecified sequence of rounding operations.</p>
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]6258
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]6259</div>
6260
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6261<!-- _______________________________________________________________________ -->
6262<div class="doc_subsubsection">
6263 <a name="int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a>
6264</div>
6265
6266<div class="doc_text">
6267
6268<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6269<p>This is an overloaded intrinsic. You can use <tt>llvm.sin</tt> on any
6270 floating point or vector of floating point type. Not all targets support all
6271 types however.</p>
6272
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6273<pre>
6274 declare float @llvm.sin.f32(float %Val)
6275 declare double @llvm.sin.f64(double %Val)
6276 declare x86_fp80 @llvm.sin.f80(x86_fp80 %Val)
6277 declare fp128 @llvm.sin.f128(fp128 %Val)
6278 declare ppc_fp128 @llvm.sin.ppcf128(ppc_fp128 %Val)
6279</pre>
6280
6281<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6282<p>The '<tt>llvm.sin.*</tt>' intrinsics return the sine of the operand.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6283
6284<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6285<p>The argument and return value are floating point numbers of the same
6286 type.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6287
6288<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6289<p>This function returns the sine of the specified operand, returning the same
6290 values as the libm <tt>sin</tt> functions would, and handles error conditions
6291 in the same way.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6292
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6293</div>
6294
6295<!-- _______________________________________________________________________ -->
6296<div class="doc_subsubsection">
6297 <a name="int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a>
6298</div>
6299
6300<div class="doc_text">
6301
6302<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6303<p>This is an overloaded intrinsic. You can use <tt>llvm.cos</tt> on any
6304 floating point or vector of floating point type. Not all targets support all
6305 types however.</p>
6306
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6307<pre>
6308 declare float @llvm.cos.f32(float %Val)
6309 declare double @llvm.cos.f64(double %Val)
6310 declare x86_fp80 @llvm.cos.f80(x86_fp80 %Val)
6311 declare fp128 @llvm.cos.f128(fp128 %Val)
6312 declare ppc_fp128 @llvm.cos.ppcf128(ppc_fp128 %Val)
6313</pre>
6314
6315<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6316<p>The '<tt>llvm.cos.*</tt>' intrinsics return the cosine of the operand.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6317
6318<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6319<p>The argument and return value are floating point numbers of the same
6320 type.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6321
6322<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6323<p>This function returns the cosine of the specified operand, returning the same
6324 values as the libm <tt>cos</tt> functions would, and handles error conditions
6325 in the same way.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6326
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6327</div>
6328
6329<!-- _______________________________________________________________________ -->
6330<div class="doc_subsubsection">
6331 <a name="int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a>
6332</div>
6333
6334<div class="doc_text">
6335
6336<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6337<p>This is an overloaded intrinsic. You can use <tt>llvm.pow</tt> on any
6338 floating point or vector of floating point type. Not all targets support all
6339 types however.</p>
6340
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6341<pre>
6342 declare float @llvm.pow.f32(float %Val, float %Power)
6343 declare double @llvm.pow.f64(double %Val, double %Power)
6344 declare x86_fp80 @llvm.pow.f80(x86_fp80 %Val, x86_fp80 %Power)
6345 declare fp128 @llvm.pow.f128(fp128 %Val, fp128 %Power)
6346 declare ppc_fp128 @llvm.pow.ppcf128(ppc_fp128 %Val, ppc_fp128 Power)
6347</pre>
6348
6349<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6350<p>The '<tt>llvm.pow.*</tt>' intrinsics return the first operand raised to the
6351 specified (positive or negative) power.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6352
6353<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6354<p>The second argument is a floating point power, and the first is a value to
6355 raise to that power.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6356
6357<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6358<p>This function returns the first value raised to the second power, returning
6359 the same values as the libm <tt>pow</tt> functions would, and handles error
6360 conditions in the same way.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6361
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6362</div>
6363
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6364<!-- ======================================================================= -->
6365<div class="doc_subsection">
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]6366 <a name="int_manip">Bit Manipulation Intrinsics</a>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6367</div>
6368
6369<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6370
6371<p>LLVM provides intrinsics for a few important bit manipulation operations.
6372 These allow efficient code generation for some algorithms.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6373
6374</div>
6375
6376<!-- _______________________________________________________________________ -->
6377<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6378 <a name="int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a>
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]6379</div>
6380
6381<div class="doc_text">
6382
6383<h5>Syntax:</h5>
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]6384<p>This is an overloaded intrinsic function. You can use bswap on any integer
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6385 type that is an even number of bytes (i.e. BitWidth % 16 == 0).</p>
6386
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]6387<pre>
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]6388 declare i16 @llvm.bswap.i16(i16 &lt;id&gt;)
6389 declare i32 @llvm.bswap.i32(i32 &lt;id&gt;)
6390 declare i64 @llvm.bswap.i64(i64 &lt;id&gt;)
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]6391</pre>
6392
6393<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6394<p>The '<tt>llvm.bswap</tt>' family of intrinsics is used to byte swap integer
6395 values with an even number of bytes (positive multiple of 16 bits). These
6396 are useful for performing operations on data that is not in the target's
6397 native byte order.</p>
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]6398
6399<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6400<p>The <tt>llvm.bswap.i16</tt> intrinsic returns an i16 value that has the high
6401 and low byte of the input i16 swapped. Similarly,
6402 the <tt>llvm.bswap.i32</tt> intrinsic returns an i32 value that has the four
6403 bytes of the input i32 swapped, so that if the input bytes are numbered 0, 1,
6404 2, 3 then the returned i32 will have its bytes in 3, 2, 1, 0 order.
6405 The <tt>llvm.bswap.i48</tt>, <tt>llvm.bswap.i64</tt> and other intrinsics
6406 extend this concept to additional even-byte lengths (6 bytes, 8 bytes and
6407 more, respectively).</p>
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]6408
6409</div>
6410
6411<!-- _______________________________________________________________________ -->
6412<div class="doc_subsubsection">
Reid Spencerb4f9a6f2006-01-16 21:12:35 +0000[diff] [blame]6413 <a name="int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic</a>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6414</div>
6415
6416<div class="doc_text">
6417
6418<h5>Syntax:</h5>
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]6419<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]6420 width. Not all targets support all bit widths however.</p>
6421
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6422<pre>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6423 declare i8 @llvm.ctpop.i8(i8 &lt;src&gt;)
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]6424 declare i16 @llvm.ctpop.i16(i16 &lt;src&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]6425 declare i32 @llvm.ctpop.i32(i32 &lt;src&gt;)
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]6426 declare i64 @llvm.ctpop.i64(i64 &lt;src&gt;)
6427 declare i256 @llvm.ctpop.i256(i256 &lt;src&gt;)
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6428</pre>
6429
6430<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6431<p>The '<tt>llvm.ctpop</tt>' family of intrinsics counts the number of bits set
6432 in a value.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6433
6434<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6435<p>The only argument is the value to be counted. The argument may be of any
6436 integer type. The return type must match the argument type.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6437
6438<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6439<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]6440
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6441</div>
6442
6443<!-- _______________________________________________________________________ -->
6444<div class="doc_subsubsection">
Chris Lattnerb748c672006-01-16 22:34:14 +0000[diff] [blame]6445 <a name="int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic</a>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6446</div>
6447
6448<div class="doc_text">
6449
6450<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6451<p>This is an overloaded intrinsic. You can use <tt>llvm.ctlz</tt> on any
6452 integer bit width. Not all targets support all bit widths however.</p>
6453
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6454<pre>
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]6455 declare i8 @llvm.ctlz.i8 (i8 &lt;src&gt;)
6456 declare i16 @llvm.ctlz.i16(i16 &lt;src&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]6457 declare i32 @llvm.ctlz.i32(i32 &lt;src&gt;)
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]6458 declare i64 @llvm.ctlz.i64(i64 &lt;src&gt;)
6459 declare i256 @llvm.ctlz.i256(i256 &lt;src&gt;)
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6460</pre>
6461
6462<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6463<p>The '<tt>llvm.ctlz</tt>' family of intrinsic functions counts the number of
6464 leading zeros in a variable.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6465
6466<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6467<p>The only argument is the value to be counted. The argument may be of any
6468 integer type. The return type must match the argument type.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6469
6470<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6471<p>The '<tt>llvm.ctlz</tt>' intrinsic counts the leading (most significant)
6472 zeros in a variable. If the src == 0 then the result is the size in bits of
6473 the type of src. For example, <tt>llvm.ctlz(i32 2) = 30</tt>.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6474
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6475</div>
Chris Lattner3b4f4372004-06-11 02:28:03 +0000[diff] [blame]6476
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]6477<!-- _______________________________________________________________________ -->
6478<div class="doc_subsubsection">
Chris Lattnerb748c672006-01-16 22:34:14 +0000[diff] [blame]6479 <a name="int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic</a>
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]6480</div>
6481
6482<div class="doc_text">
6483
6484<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6485<p>This is an overloaded intrinsic. You can use <tt>llvm.cttz</tt> on any
6486 integer bit width. Not all targets support all bit widths however.</p>
6487
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]6488<pre>
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]6489 declare i8 @llvm.cttz.i8 (i8 &lt;src&gt;)
6490 declare i16 @llvm.cttz.i16(i16 &lt;src&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]6491 declare i32 @llvm.cttz.i32(i32 &lt;src&gt;)
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]6492 declare i64 @llvm.cttz.i64(i64 &lt;src&gt;)
6493 declare i256 @llvm.cttz.i256(i256 &lt;src&gt;)
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]6494</pre>
6495
6496<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6497<p>The '<tt>llvm.cttz</tt>' family of intrinsic functions counts the number of
6498 trailing zeros.</p>
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]6499
6500<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6501<p>The only argument is the value to be counted. The argument may be of any
6502 integer type. The return type must match the argument type.</p>
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]6503
6504<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6505<p>The '<tt>llvm.cttz</tt>' intrinsic counts the trailing (least significant)
6506 zeros in a variable. If the src == 0 then the result is the size in bits of
6507 the type of src. For example, <tt>llvm.cttz(2) = 1</tt>.</p>
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]6508
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]6509</div>
6510
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]6511<!-- ======================================================================= -->
6512<div class="doc_subsection">
6513 <a name="int_overflow">Arithmetic with Overflow Intrinsics</a>
6514</div>
6515
6516<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6517
6518<p>LLVM provides intrinsics for some arithmetic with overflow operations.</p>
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]6519
6520</div>
6521
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6522<!-- _______________________________________________________________________ -->
6523<div class="doc_subsubsection">
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]6524 <a name="int_sadd_overflow">'<tt>llvm.sadd.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6525</div>
6526
6527<div class="doc_text">
6528
6529<h5>Syntax:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6530<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]6531 on any integer bit width.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6532
6533<pre>
6534 declare {i16, i1} @llvm.sadd.with.overflow.i16(i16 %a, i16 %b)
6535 declare {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
6536 declare {i64, i1} @llvm.sadd.with.overflow.i64(i64 %a, i64 %b)
6537</pre>
6538
6539<h5>Overview:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6540<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6541 a signed addition of the two arguments, and indicate whether an overflow
6542 occurred during the signed summation.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6543
6544<h5>Arguments:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6545<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]6546 be of integer types of any bit width, but they must have the same bit
6547 width. The second element of the result structure must be of
6548 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6549 undergo signed addition.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6550
6551<h5>Semantics:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6552<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6553 a signed addition of the two variables. They return a structure &mdash; the
6554 first element of which is the signed summation, and the second element of
6555 which is a bit specifying if the signed summation resulted in an
6556 overflow.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6557
6558<h5>Examples:</h5>
6559<pre>
6560 %res = call {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
6561 %sum = extractvalue {i32, i1} %res, 0
6562 %obit = extractvalue {i32, i1} %res, 1
6563 br i1 %obit, label %overflow, label %normal
6564</pre>
6565
6566</div>
6567
6568<!-- _______________________________________________________________________ -->
6569<div class="doc_subsubsection">
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]6570 <a name="int_uadd_overflow">'<tt>llvm.uadd.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6571</div>
6572
6573<div class="doc_text">
6574
6575<h5>Syntax:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6576<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]6577 on any integer bit width.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6578
6579<pre>
6580 declare {i16, i1} @llvm.uadd.with.overflow.i16(i16 %a, i16 %b)
6581 declare {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
6582 declare {i64, i1} @llvm.uadd.with.overflow.i64(i64 %a, i64 %b)
6583</pre>
6584
6585<h5>Overview:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6586<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6587 an unsigned addition of the two arguments, and indicate whether a carry
6588 occurred during the unsigned summation.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6589
6590<h5>Arguments:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6591<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]6592 be of integer types of any bit width, but they must have the same bit
6593 width. The second element of the result structure must be of
6594 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6595 undergo unsigned addition.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6596
6597<h5>Semantics:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6598<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6599 an unsigned addition of the two arguments. They return a structure &mdash;
6600 the first element of which is the sum, and the second element of which is a
6601 bit specifying if the unsigned summation resulted in a carry.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6602
6603<h5>Examples:</h5>
6604<pre>
6605 %res = call {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
6606 %sum = extractvalue {i32, i1} %res, 0
6607 %obit = extractvalue {i32, i1} %res, 1
6608 br i1 %obit, label %carry, label %normal
6609</pre>
6610
6611</div>
6612
6613<!-- _______________________________________________________________________ -->
6614<div class="doc_subsubsection">
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]6615 <a name="int_ssub_overflow">'<tt>llvm.ssub.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6616</div>
6617
6618<div class="doc_text">
6619
6620<h5>Syntax:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6621<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]6622 on any integer bit width.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6623
6624<pre>
6625 declare {i16, i1} @llvm.ssub.with.overflow.i16(i16 %a, i16 %b)
6626 declare {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
6627 declare {i64, i1} @llvm.ssub.with.overflow.i64(i64 %a, i64 %b)
6628</pre>
6629
6630<h5>Overview:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6631<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6632 a signed subtraction of the two arguments, and indicate whether an overflow
6633 occurred during the signed subtraction.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6634
6635<h5>Arguments:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6636<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]6637 be of integer types of any bit width, but they must have the same bit
6638 width. The second element of the result structure must be of
6639 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6640 undergo signed subtraction.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6641
6642<h5>Semantics:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6643<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6644 a signed subtraction of the two arguments. They return a structure &mdash;
6645 the first element of which is the subtraction, and the second element of
6646 which is a bit specifying if the signed subtraction resulted in an
6647 overflow.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6648
6649<h5>Examples:</h5>
6650<pre>
6651 %res = call {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
6652 %sum = extractvalue {i32, i1} %res, 0
6653 %obit = extractvalue {i32, i1} %res, 1
6654 br i1 %obit, label %overflow, label %normal
6655</pre>
6656
6657</div>
6658
6659<!-- _______________________________________________________________________ -->
6660<div class="doc_subsubsection">
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]6661 <a name="int_usub_overflow">'<tt>llvm.usub.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6662</div>
6663
6664<div class="doc_text">
6665
6666<h5>Syntax:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6667<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]6668 on any integer bit width.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6669
6670<pre>
6671 declare {i16, i1} @llvm.usub.with.overflow.i16(i16 %a, i16 %b)
6672 declare {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
6673 declare {i64, i1} @llvm.usub.with.overflow.i64(i64 %a, i64 %b)
6674</pre>
6675
6676<h5>Overview:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6677<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6678 an unsigned subtraction of the two arguments, and indicate whether an
6679 overflow occurred during the unsigned subtraction.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6680
6681<h5>Arguments:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6682<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]6683 be of integer types of any bit width, but they must have the same bit
6684 width. The second element of the result structure must be of
6685 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6686 undergo unsigned subtraction.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6687
6688<h5>Semantics:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6689<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6690 an unsigned subtraction of the two arguments. They return a structure &mdash;
6691 the first element of which is the subtraction, and the second element of
6692 which is a bit specifying if the unsigned subtraction resulted in an
6693 overflow.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6694
6695<h5>Examples:</h5>
6696<pre>
6697 %res = call {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
6698 %sum = extractvalue {i32, i1} %res, 0
6699 %obit = extractvalue {i32, i1} %res, 1
6700 br i1 %obit, label %overflow, label %normal
6701</pre>
6702
6703</div>
6704
6705<!-- _______________________________________________________________________ -->
6706<div class="doc_subsubsection">
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]6707 <a name="int_smul_overflow">'<tt>llvm.smul.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6708</div>
6709
6710<div class="doc_text">
6711
6712<h5>Syntax:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6713<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]6714 on any integer bit width.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6715
6716<pre>
6717 declare {i16, i1} @llvm.smul.with.overflow.i16(i16 %a, i16 %b)
6718 declare {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
6719 declare {i64, i1} @llvm.smul.with.overflow.i64(i64 %a, i64 %b)
6720</pre>
6721
6722<h5>Overview:</h5>
6723
6724<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6725 a signed multiplication of the two arguments, and indicate whether an
6726 overflow occurred during the signed multiplication.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6727
6728<h5>Arguments:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6729<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]6730 be of integer types of any bit width, but they must have the same bit
6731 width. The second element of the result structure must be of
6732 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6733 undergo signed multiplication.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6734
6735<h5>Semantics:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6736<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6737 a signed multiplication of the two arguments. They return a structure &mdash;
6738 the first element of which is the multiplication, and the second element of
6739 which is a bit specifying if the signed multiplication resulted in an
6740 overflow.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6741
6742<h5>Examples:</h5>
6743<pre>
6744 %res = call {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
6745 %sum = extractvalue {i32, i1} %res, 0
6746 %obit = extractvalue {i32, i1} %res, 1
6747 br i1 %obit, label %overflow, label %normal
6748</pre>
6749
Reid Spencer5bf54c82007-04-11 23:23:49 +0000[diff] [blame]6750</div>
6751
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]6752<!-- _______________________________________________________________________ -->
6753<div class="doc_subsubsection">
6754 <a name="int_umul_overflow">'<tt>llvm.umul.with.overflow.*</tt>' Intrinsics</a>
6755</div>
6756
6757<div class="doc_text">
6758
6759<h5>Syntax:</h5>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]6760<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]6761 on any integer bit width.</p>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]6762
6763<pre>
6764 declare {i16, i1} @llvm.umul.with.overflow.i16(i16 %a, i16 %b)
6765 declare {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
6766 declare {i64, i1} @llvm.umul.with.overflow.i64(i64 %a, i64 %b)
6767</pre>
6768
6769<h5>Overview:</h5>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]6770<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6771 a unsigned multiplication of the two arguments, and indicate whether an
6772 overflow occurred during the unsigned multiplication.</p>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]6773
6774<h5>Arguments:</h5>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]6775<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]6776 be of integer types of any bit width, but they must have the same bit
6777 width. The second element of the result structure must be of
6778 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6779 undergo unsigned multiplication.</p>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]6780
6781<h5>Semantics:</h5>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]6782<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6783 an unsigned multiplication of the two arguments. They return a structure
6784 &mdash; the first element of which is the multiplication, and the second
6785 element of which is a bit specifying if the unsigned multiplication resulted
6786 in an overflow.</p>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]6787
6788<h5>Examples:</h5>
6789<pre>
6790 %res = call {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
6791 %sum = extractvalue {i32, i1} %res, 0
6792 %obit = extractvalue {i32, i1} %res, 1
6793 br i1 %obit, label %overflow, label %normal
6794</pre>
6795
6796</div>
6797
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]6798<!-- ======================================================================= -->
6799<div class="doc_subsection">
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]6800 <a name="int_fp16">Half Precision Floating Point Intrinsics</a>
6801</div>
6802
6803<div class="doc_text">
6804
Chris Lattner022a9fb2010-03-15 04:12:21 +0000[diff] [blame]6805<p>Half precision floating point is a storage-only format. This means that it is
6806 a dense encoding (in memory) but does not support computation in the
6807 format.</p>
Chris Lattnerbbd8bd32010-03-14 23:03:31 +0000[diff] [blame]6808
Chris Lattner022a9fb2010-03-15 04:12:21 +0000[diff] [blame]6809<p>This means that code must first load the half-precision floating point
Chris Lattnerbbd8bd32010-03-14 23:03:31 +0000[diff] [blame]6810 value as an i16, then convert it to float with <a
6811 href="#int_convert_from_fp16"><tt>llvm.convert.from.fp16</tt></a>.
6812 Computation can then be performed on the float value (including extending to
Chris Lattner022a9fb2010-03-15 04:12:21 +0000[diff] [blame]6813 double etc). To store the value back to memory, it is first converted to
6814 float if needed, then converted to i16 with
Chris Lattnerbbd8bd32010-03-14 23:03:31 +0000[diff] [blame]6815 <a href="#int_convert_to_fp16"><tt>llvm.convert.to.fp16</tt></a>, then
6816 storing as an i16 value.</p>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]6817</div>
6818
6819<!-- _______________________________________________________________________ -->
6820<div class="doc_subsubsection">
Chris Lattnerbbd8bd32010-03-14 23:03:31 +0000[diff] [blame]6821 <a name="int_convert_to_fp16">'<tt>llvm.convert.to.fp16</tt>' Intrinsic</a>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]6822</div>
6823
6824<div class="doc_text">
6825
6826<h5>Syntax:</h5>
6827<pre>
6828 declare i16 @llvm.convert.to.fp16(f32 %a)
6829</pre>
6830
6831<h5>Overview:</h5>
6832<p>The '<tt>llvm.convert.to.fp16</tt>' intrinsic function performs
6833 a conversion from single precision floating point format to half precision
6834 floating point format.</p>
6835
6836<h5>Arguments:</h5>
6837<p>The intrinsic function contains single argument - the value to be
6838 converted.</p>
6839
6840<h5>Semantics:</h5>
6841<p>The '<tt>llvm.convert.to.fp16</tt>' intrinsic function performs
6842 a conversion from single precision floating point format to half precision
Chris Lattner022a9fb2010-03-15 04:12:21 +0000[diff] [blame]6843 floating point format. The return value is an <tt>i16</tt> which
Chris Lattnerbbd8bd32010-03-14 23:03:31 +0000[diff] [blame]6844 contains the converted number.</p>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]6845
6846<h5>Examples:</h5>
6847<pre>
6848 %res = call i16 @llvm.convert.to.fp16(f32 %a)
6849 store i16 %res, i16* @x, align 2
6850</pre>
6851
6852</div>
6853
6854<!-- _______________________________________________________________________ -->
6855<div class="doc_subsubsection">
Chris Lattnerbbd8bd32010-03-14 23:03:31 +0000[diff] [blame]6856 <a name="int_convert_from_fp16">'<tt>llvm.convert.from.fp16</tt>' Intrinsic</a>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]6857</div>
6858
6859<div class="doc_text">
6860
6861<h5>Syntax:</h5>
6862<pre>
6863 declare f32 @llvm.convert.from.fp16(i16 %a)
6864</pre>
6865
6866<h5>Overview:</h5>
6867<p>The '<tt>llvm.convert.from.fp16</tt>' intrinsic function performs
6868 a conversion from half precision floating point format to single precision
6869 floating point format.</p>
6870
6871<h5>Arguments:</h5>
6872<p>The intrinsic function contains single argument - the value to be
6873 converted.</p>
6874
6875<h5>Semantics:</h5>
6876<p>The '<tt>llvm.convert.from.fp16</tt>' intrinsic function performs a
Chris Lattner022a9fb2010-03-15 04:12:21 +0000[diff] [blame]6877 conversion from half single precision floating point format to single
Chris Lattnerbbd8bd32010-03-14 23:03:31 +0000[diff] [blame]6878 precision floating point format. The input half-float value is represented by
6879 an <tt>i16</tt> value.</p>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]6880
6881<h5>Examples:</h5>
6882<pre>
6883 %a = load i16* @x, align 2
6884 %res = call f32 @llvm.convert.from.fp16(i16 %a)
6885</pre>
6886
6887</div>
6888
6889<!-- ======================================================================= -->
6890<div class="doc_subsection">
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]6891 <a name="int_debugger">Debugger Intrinsics</a>
6892</div>
6893
6894<div class="doc_text">
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]6895
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6896<p>The LLVM debugger intrinsics (which all start with <tt>llvm.dbg.</tt>
6897 prefix), are described in
6898 the <a href="SourceLevelDebugging.html#format_common_intrinsics">LLVM Source
6899 Level Debugging</a> document.</p>
6900
6901</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]6902
Jim Laskey2211f492007-03-14 19:31:19 +0000[diff] [blame]6903<!-- ======================================================================= -->
6904<div class="doc_subsection">
6905 <a name="int_eh">Exception Handling Intrinsics</a>
6906</div>
6907
6908<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6909
6910<p>The LLVM exception handling intrinsics (which all start with
6911 <tt>llvm.eh.</tt> prefix), are described in
6912 the <a href="ExceptionHandling.html#format_common_intrinsics">LLVM Exception
6913 Handling</a> document.</p>
6914
Jim Laskey2211f492007-03-14 19:31:19 +0000[diff] [blame]6915</div>
6916
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]6917<!-- ======================================================================= -->
6918<div class="doc_subsection">
Duncan Sands86e01192007-09-11 14:10:23 +0000[diff] [blame]6919 <a name="int_trampoline">Trampoline Intrinsic</a>
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]6920</div>
6921
6922<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6923
6924<p>This intrinsic makes it possible to excise one parameter, marked with
6925 the <tt>nest</tt> attribute, from a function. The result is a callable
6926 function pointer lacking the nest parameter - the caller does not need to
6927 provide a value for it. Instead, the value to use is stored in advance in a
6928 "trampoline", a block of memory usually allocated on the stack, which also
6929 contains code to splice the nest value into the argument list. This is used
6930 to implement the GCC nested function address extension.</p>
6931
6932<p>For example, if the function is
6933 <tt>i32 f(i8* nest %c, i32 %x, i32 %y)</tt> then the resulting function
6934 pointer has signature <tt>i32 (i32, i32)*</tt>. It can be created as
6935 follows:</p>
6936
6937<div class="doc_code">
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]6938<pre>
Duncan Sands86e01192007-09-11 14:10:23 +0000[diff] [blame]6939 %tramp = alloca [10 x i8], align 4 ; size and alignment only correct for X86
6940 %tramp1 = getelementptr [10 x i8]* %tramp, i32 0, i32 0
6941 %p = call i8* @llvm.init.trampoline( i8* %tramp1, i8* bitcast (i32 (i8* nest , i32, i32)* @f to i8*), i8* %nval )
6942 %fp = bitcast i8* %p to i32 (i32, i32)*
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]6943</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6944</div>
6945
6946<p>The call <tt>%val = call i32 %fp( i32 %x, i32 %y )</tt> is then equivalent
6947 to <tt>%val = call i32 %f( i8* %nval, i32 %x, i32 %y )</tt>.</p>
6948
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]6949</div>
6950
6951<!-- _______________________________________________________________________ -->
6952<div class="doc_subsubsection">
6953 <a name="int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a>
6954</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6955
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]6956<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6957
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]6958<h5>Syntax:</h5>
6959<pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6960 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]6961</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6962
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]6963<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6964<p>This fills the memory pointed to by <tt>tramp</tt> with code and returns a
6965 function pointer suitable for executing it.</p>
6966
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]6967<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6968<p>The <tt>llvm.init.trampoline</tt> intrinsic takes three arguments, all
6969 pointers. The <tt>tramp</tt> argument must point to a sufficiently large and
6970 sufficiently aligned block of memory; this memory is written to by the
6971 intrinsic. Note that the size and the alignment are target-specific - LLVM
6972 currently provides no portable way of determining them, so a front-end that
6973 generates this intrinsic needs to have some target-specific knowledge.
6974 The <tt>func</tt> argument must hold a function bitcast to
6975 an <tt>i8*</tt>.</p>
6976
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]6977<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6978<p>The block of memory pointed to by <tt>tramp</tt> is filled with target
6979 dependent code, turning it into a function. A pointer to this function is
6980 returned, but needs to be bitcast to an <a href="#int_trampoline">appropriate
6981 function pointer type</a> before being called. The new function's signature
6982 is the same as that of <tt>func</tt> with any arguments marked with
6983 the <tt>nest</tt> attribute removed. At most one such <tt>nest</tt> argument
6984 is allowed, and it must be of pointer type. Calling the new function is
6985 equivalent to calling <tt>func</tt> with the same argument list, but
6986 with <tt>nval</tt> used for the missing <tt>nest</tt> argument. If, after
6987 calling <tt>llvm.init.trampoline</tt>, the memory pointed to
6988 by <tt>tramp</tt> is modified, then the effect of any later call to the
6989 returned function pointer is undefined.</p>
6990
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]6991</div>
6992
6993<!-- ======================================================================= -->
6994<div class="doc_subsection">
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]6995 <a name="int_atomics">Atomic Operations and Synchronization Intrinsics</a>
6996</div>
6997
6998<div class="doc_text">
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]6999
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7000<p>These intrinsic functions expand the "universal IR" of LLVM to represent
7001 hardware constructs for atomic operations and memory synchronization. This
7002 provides an interface to the hardware, not an interface to the programmer. It
7003 is aimed at a low enough level to allow any programming models or APIs
7004 (Application Programming Interfaces) which need atomic behaviors to map
7005 cleanly onto it. It is also modeled primarily on hardware behavior. Just as
7006 hardware provides a "universal IR" for source languages, it also provides a
7007 starting point for developing a "universal" atomic operation and
7008 synchronization IR.</p>
7009
7010<p>These do <em>not</em> form an API such as high-level threading libraries,
7011 software transaction memory systems, atomic primitives, and intrinsic
7012 functions as found in BSD, GNU libc, atomic_ops, APR, and other system and
7013 application libraries. The hardware interface provided by LLVM should allow
7014 a clean implementation of all of these APIs and parallel programming models.
7015 No one model or paradigm should be selected above others unless the hardware
7016 itself ubiquitously does so.</p>
7017
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7018</div>
7019
7020<!-- _______________________________________________________________________ -->
7021<div class="doc_subsubsection">
7022 <a name="int_memory_barrier">'<tt>llvm.memory.barrier</tt>' Intrinsic</a>
7023</div>
7024<div class="doc_text">
7025<h5>Syntax:</h5>
7026<pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7027 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]7028</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7029
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7030<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7031<p>The <tt>llvm.memory.barrier</tt> intrinsic guarantees ordering between
7032 specific pairs of memory access types.</p>
7033
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7034<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7035<p>The <tt>llvm.memory.barrier</tt> intrinsic requires five boolean arguments.
7036 The first four arguments enables a specific barrier as listed below. The
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]7037 fifth argument specifies that the barrier applies to io or device or uncached
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7038 memory.</p>
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7039
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7040<ul>
7041 <li><tt>ll</tt>: load-load barrier</li>
7042 <li><tt>ls</tt>: load-store barrier</li>
7043 <li><tt>sl</tt>: store-load barrier</li>
7044 <li><tt>ss</tt>: store-store barrier</li>
7045 <li><tt>device</tt>: barrier applies to device and uncached memory also.</li>
7046</ul>
7047
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7048<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7049<p>This intrinsic causes the system to enforce some ordering constraints upon
7050 the loads and stores of the program. This barrier does not
7051 indicate <em>when</em> any events will occur, it only enforces
7052 an <em>order</em> in which they occur. For any of the specified pairs of load
7053 and store operations (f.ex. load-load, or store-load), all of the first
7054 operations preceding the barrier will complete before any of the second
7055 operations succeeding the barrier begin. Specifically the semantics for each
7056 pairing is as follows:</p>
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7057
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7058<ul>
7059 <li><tt>ll</tt>: All loads before the barrier must complete before any load
7060 after the barrier begins.</li>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]7061 <li><tt>ls</tt>: All loads before the barrier must complete before any
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7062 store after the barrier begins.</li>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]7063 <li><tt>ss</tt>: All stores before the barrier must complete before any
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7064 store after the barrier begins.</li>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]7065 <li><tt>sl</tt>: All stores before the barrier must complete before any
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7066 load after the barrier begins.</li>
7067</ul>
7068
7069<p>These semantics are applied with a logical "and" behavior when more than one
7070 is enabled in a single memory barrier intrinsic.</p>
7071
7072<p>Backends may implement stronger barriers than those requested when they do
7073 not support as fine grained a barrier as requested. Some architectures do
7074 not need all types of barriers and on such architectures, these become
7075 noops.</p>
7076
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7077<h5>Example:</h5>
7078<pre>
Victor Hernandeza70c6df2009-10-26 23:44:29 +0000[diff] [blame]7079%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7080%ptr = bitcast i8* %mallocP to i32*
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7081 store i32 4, %ptr
7082
7083%result1 = load i32* %ptr <i>; yields {i32}:result1 = 4</i>
7084 call void @llvm.memory.barrier( i1 false, i1 true, i1 false, i1 false )
7085 <i>; guarantee the above finishes</i>
7086 store i32 8, %ptr <i>; before this begins</i>
7087</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7088
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7089</div>
7090
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7091<!-- _______________________________________________________________________ -->
7092<div class="doc_subsubsection">
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7093 <a name="int_atomic_cmp_swap">'<tt>llvm.atomic.cmp.swap.*</tt>' Intrinsic</a>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7094</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7095
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7096<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7097
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7098<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7099<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.cmp.swap</tt> on
7100 any integer bit width and for different address spaces. Not all targets
7101 support all bit widths however.</p>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7102
7103<pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7104 declare i8 @llvm.atomic.cmp.swap.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;cmp&gt;, i8 &lt;val&gt; )
7105 declare i16 @llvm.atomic.cmp.swap.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;cmp&gt;, i16 &lt;val&gt; )
7106 declare i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;cmp&gt;, i32 &lt;val&gt; )
7107 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]7108</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7109
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7110<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7111<p>This loads a value in memory and compares it to a given value. If they are
7112 equal, it stores a new value into the memory.</p>
7113
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7114<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7115<p>The <tt>llvm.atomic.cmp.swap</tt> intrinsic takes three arguments. The result
7116 as well as both <tt>cmp</tt> and <tt>val</tt> must be integer values with the
7117 same bit width. The <tt>ptr</tt> argument must be a pointer to a value of
7118 this integer type. While any bit width integer may be used, targets may only
7119 lower representations they support in hardware.</p>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7120
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7121<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7122<p>This entire intrinsic must be executed atomically. It first loads the value
7123 in memory pointed to by <tt>ptr</tt> and compares it with the
7124 value <tt>cmp</tt>. If they are equal, <tt>val</tt> is stored into the
7125 memory. The loaded value is yielded in all cases. This provides the
7126 equivalent of an atomic compare-and-swap operation within the SSA
7127 framework.</p>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7128
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7129<h5>Examples:</h5>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7130<pre>
Victor Hernandeza70c6df2009-10-26 23:44:29 +0000[diff] [blame]7131%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7132%ptr = bitcast i8* %mallocP to i32*
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7133 store i32 4, %ptr
7134
7135%val1 = add i32 4, 4
Mon P Wang2c839d42008-07-30 04:36:53 +0000[diff] [blame]7136%result1 = call i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* %ptr, i32 4, %val1 )
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7137 <i>; yields {i32}:result1 = 4</i>
7138%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
7139%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
7140
7141%val2 = add i32 1, 1
Mon P Wang2c839d42008-07-30 04:36:53 +0000[diff] [blame]7142%result2 = call i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* %ptr, i32 5, %val2 )
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7143 <i>; yields {i32}:result2 = 8</i>
7144%stored2 = icmp eq i32 %result2, 5 <i>; yields {i1}:stored2 = false</i>
7145
7146%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 8</i>
7147</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7148
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7149</div>
7150
7151<!-- _______________________________________________________________________ -->
7152<div class="doc_subsubsection">
7153 <a name="int_atomic_swap">'<tt>llvm.atomic.swap.*</tt>' Intrinsic</a>
7154</div>
7155<div class="doc_text">
7156<h5>Syntax:</h5>
7157
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7158<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.swap</tt> on any
7159 integer bit width. Not all targets support all bit widths however.</p>
7160
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7161<pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7162 declare i8 @llvm.atomic.swap.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;val&gt; )
7163 declare i16 @llvm.atomic.swap.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;val&gt; )
7164 declare i32 @llvm.atomic.swap.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;val&gt; )
7165 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]7166</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7167
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7168<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7169<p>This intrinsic loads the value stored in memory at <tt>ptr</tt> and yields
7170 the value from memory. It then stores the value in <tt>val</tt> in the memory
7171 at <tt>ptr</tt>.</p>
7172
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7173<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7174<p>The <tt>llvm.atomic.swap</tt> intrinsic takes two arguments. Both
7175 the <tt>val</tt> argument and the result must be integers of the same bit
7176 width. The first argument, <tt>ptr</tt>, must be a pointer to a value of this
7177 integer type. The targets may only lower integer representations they
7178 support.</p>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7179
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7180<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7181<p>This intrinsic loads the value pointed to by <tt>ptr</tt>, yields it, and
7182 stores <tt>val</tt> back into <tt>ptr</tt> atomically. This provides the
7183 equivalent of an atomic swap operation within the SSA framework.</p>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7184
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7185<h5>Examples:</h5>
7186<pre>
Victor Hernandeza70c6df2009-10-26 23:44:29 +0000[diff] [blame]7187%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7188%ptr = bitcast i8* %mallocP to i32*
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7189 store i32 4, %ptr
7190
7191%val1 = add i32 4, 4
Mon P Wang2c839d42008-07-30 04:36:53 +0000[diff] [blame]7192%result1 = call i32 @llvm.atomic.swap.i32.p0i32( i32* %ptr, i32 %val1 )
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7193 <i>; yields {i32}:result1 = 4</i>
7194%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
7195%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
7196
7197%val2 = add i32 1, 1
Mon P Wang2c839d42008-07-30 04:36:53 +0000[diff] [blame]7198%result2 = call i32 @llvm.atomic.swap.i32.p0i32( i32* %ptr, i32 %val2 )
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7199 <i>; yields {i32}:result2 = 8</i>
7200
7201%stored2 = icmp eq i32 %result2, 8 <i>; yields {i1}:stored2 = true</i>
7202%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 2</i>
7203</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7204
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7205</div>
7206
7207<!-- _______________________________________________________________________ -->
7208<div class="doc_subsubsection">
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7209 <a name="int_atomic_load_add">'<tt>llvm.atomic.load.add.*</tt>' Intrinsic</a>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7210
7211</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7212
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7213<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7214
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7215<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7216<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.load.add</tt> on
7217 any integer bit width. Not all targets support all bit widths however.</p>
7218
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7219<pre>
Chris Lattner966a3822010-05-05 23:29:09 +0000[diff] [blame]7220 declare i8 @llvm.atomic.load.add.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
7221 declare i16 @llvm.atomic.load.add.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
7222 declare i32 @llvm.atomic.load.add.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
7223 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]7224</pre>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7225
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7226<h5>Overview:</h5>
7227<p>This intrinsic adds <tt>delta</tt> to the value stored in memory
7228 at <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.</p>
7229
7230<h5>Arguments:</h5>
7231<p>The intrinsic takes two arguments, the first a pointer to an integer value
7232 and the second an integer value. The result is also an integer value. These
7233 integer types can have any bit width, but they must all have the same bit
7234 width. The targets may only lower integer representations they support.</p>
7235
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7236<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7237<p>This intrinsic does a series of operations atomically. It first loads the
7238 value stored at <tt>ptr</tt>. It then adds <tt>delta</tt>, stores the result
7239 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]7240
7241<h5>Examples:</h5>
7242<pre>
Victor Hernandeza70c6df2009-10-26 23:44:29 +0000[diff] [blame]7243%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7244%ptr = bitcast i8* %mallocP to i32*
7245 store i32 4, %ptr
Mon P Wang2c839d42008-07-30 04:36:53 +0000[diff] [blame]7246%result1 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 4 )
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7247 <i>; yields {i32}:result1 = 4</i>
Mon P Wang2c839d42008-07-30 04:36:53 +0000[diff] [blame]7248%result2 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 2 )
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7249 <i>; yields {i32}:result2 = 8</i>
Mon P Wang2c839d42008-07-30 04:36:53 +0000[diff] [blame]7250%result3 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 5 )
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7251 <i>; yields {i32}:result3 = 10</i>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7252%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 15</i>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7253</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7254
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7255</div>
7256
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7257<!-- _______________________________________________________________________ -->
7258<div class="doc_subsubsection">
7259 <a name="int_atomic_load_sub">'<tt>llvm.atomic.load.sub.*</tt>' Intrinsic</a>
7260
7261</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7262
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7263<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7264
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7265<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7266<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.load.sub</tt> on
7267 any integer bit width and for different address spaces. Not all targets
7268 support all bit widths however.</p>
7269
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7270<pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7271 declare i8 @llvm.atomic.load.sub.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
7272 declare i16 @llvm.atomic.load.sub.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
7273 declare i32 @llvm.atomic.load.sub.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
7274 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]7275</pre>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7276
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7277<h5>Overview:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]7278<p>This intrinsic subtracts <tt>delta</tt> to the value stored in memory at
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7279 <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.</p>
7280
7281<h5>Arguments:</h5>
7282<p>The intrinsic takes two arguments, the first a pointer to an integer value
7283 and the second an integer value. The result is also an integer value. These
7284 integer types can have any bit width, but they must all have the same bit
7285 width. The targets may only lower integer representations they support.</p>
7286
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7287<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7288<p>This intrinsic does a series of operations atomically. It first loads the
7289 value stored at <tt>ptr</tt>. It then subtracts <tt>delta</tt>, stores the
7290 result to <tt>ptr</tt>. It yields the original value stored
7291 at <tt>ptr</tt>.</p>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7292
7293<h5>Examples:</h5>
7294<pre>
Victor Hernandeza70c6df2009-10-26 23:44:29 +0000[diff] [blame]7295%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7296%ptr = bitcast i8* %mallocP to i32*
7297 store i32 8, %ptr
Mon P Wang2c839d42008-07-30 04:36:53 +0000[diff] [blame]7298%result1 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 4 )
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7299 <i>; yields {i32}:result1 = 8</i>
Mon P Wang2c839d42008-07-30 04:36:53 +0000[diff] [blame]7300%result2 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 2 )
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7301 <i>; yields {i32}:result2 = 4</i>
Mon P Wang2c839d42008-07-30 04:36:53 +0000[diff] [blame]7302%result3 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 5 )
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7303 <i>; yields {i32}:result3 = 2</i>
7304%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = -3</i>
7305</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7306
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7307</div>
7308
7309<!-- _______________________________________________________________________ -->
7310<div class="doc_subsubsection">
7311 <a name="int_atomic_load_and">'<tt>llvm.atomic.load.and.*</tt>' Intrinsic</a><br>
7312 <a name="int_atomic_load_nand">'<tt>llvm.atomic.load.nand.*</tt>' Intrinsic</a><br>
7313 <a name="int_atomic_load_or">'<tt>llvm.atomic.load.or.*</tt>' Intrinsic</a><br>
7314 <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]7315</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7316
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7317<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7318
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7319<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7320<p>These are overloaded intrinsics. You can
7321 use <tt>llvm.atomic.load_and</tt>, <tt>llvm.atomic.load_nand</tt>,
7322 <tt>llvm.atomic.load_or</tt>, and <tt>llvm.atomic.load_xor</tt> on any integer
7323 bit width and for different address spaces. Not all targets support all bit
7324 widths however.</p>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7325
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7326<pre>
7327 declare i8 @llvm.atomic.load.and.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
7328 declare i16 @llvm.atomic.load.and.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
7329 declare i32 @llvm.atomic.load.and.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
7330 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]7331</pre>
7332
7333<pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7334 declare i8 @llvm.atomic.load.or.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
7335 declare i16 @llvm.atomic.load.or.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
7336 declare i32 @llvm.atomic.load.or.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
7337 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]7338</pre>
7339
7340<pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7341 declare i8 @llvm.atomic.load.nand.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
7342 declare i16 @llvm.atomic.load.nand.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
7343 declare i32 @llvm.atomic.load.nand.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
7344 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]7345</pre>
7346
7347<pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7348 declare i8 @llvm.atomic.load.xor.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
7349 declare i16 @llvm.atomic.load.xor.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
7350 declare i32 @llvm.atomic.load.xor.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
7351 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]7352</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7353
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7354<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7355<p>These intrinsics bitwise the operation (and, nand, or, xor) <tt>delta</tt> to
7356 the value stored in memory at <tt>ptr</tt>. It yields the original value
7357 at <tt>ptr</tt>.</p>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7358
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7359<h5>Arguments:</h5>
7360<p>These intrinsics take two arguments, the first a pointer to an integer value
7361 and the second an integer value. The result is also an integer value. These
7362 integer types can have any bit width, but they must all have the same bit
7363 width. The targets may only lower integer representations they support.</p>
7364
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7365<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7366<p>These intrinsics does a series of operations atomically. They first load the
7367 value stored at <tt>ptr</tt>. They then do the bitwise
7368 operation <tt>delta</tt>, store the result to <tt>ptr</tt>. They yield the
7369 original value stored at <tt>ptr</tt>.</p>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7370
7371<h5>Examples:</h5>
7372<pre>
Victor Hernandeza70c6df2009-10-26 23:44:29 +0000[diff] [blame]7373%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7374%ptr = bitcast i8* %mallocP to i32*
7375 store i32 0x0F0F, %ptr
Mon P Wang2c839d42008-07-30 04:36:53 +0000[diff] [blame]7376%result0 = call i32 @llvm.atomic.load.nand.i32.p0i32( i32* %ptr, i32 0xFF )
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7377 <i>; yields {i32}:result0 = 0x0F0F</i>
Mon P Wang2c839d42008-07-30 04:36:53 +0000[diff] [blame]7378%result1 = call i32 @llvm.atomic.load.and.i32.p0i32( i32* %ptr, i32 0xFF )
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7379 <i>; yields {i32}:result1 = 0xFFFFFFF0</i>
Mon P Wang2c839d42008-07-30 04:36:53 +0000[diff] [blame]7380%result2 = call i32 @llvm.atomic.load.or.i32.p0i32( i32* %ptr, i32 0F )
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7381 <i>; yields {i32}:result2 = 0xF0</i>
Mon P Wang2c839d42008-07-30 04:36:53 +0000[diff] [blame]7382%result3 = call i32 @llvm.atomic.load.xor.i32.p0i32( i32* %ptr, i32 0F )
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7383 <i>; yields {i32}:result3 = FF</i>
7384%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = F0</i>
7385</pre>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7386
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7387</div>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7388
7389<!-- _______________________________________________________________________ -->
7390<div class="doc_subsubsection">
7391 <a name="int_atomic_load_max">'<tt>llvm.atomic.load.max.*</tt>' Intrinsic</a><br>
7392 <a name="int_atomic_load_min">'<tt>llvm.atomic.load.min.*</tt>' Intrinsic</a><br>
7393 <a name="int_atomic_load_umax">'<tt>llvm.atomic.load.umax.*</tt>' Intrinsic</a><br>
7394 <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]7395</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7396
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7397<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7398
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7399<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7400<p>These are overloaded intrinsics. You can use <tt>llvm.atomic.load_max</tt>,
7401 <tt>llvm.atomic.load_min</tt>, <tt>llvm.atomic.load_umax</tt>, and
7402 <tt>llvm.atomic.load_umin</tt> on any integer bit width and for different
7403 address spaces. Not all targets support all bit widths however.</p>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7404
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7405<pre>
7406 declare i8 @llvm.atomic.load.max.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
7407 declare i16 @llvm.atomic.load.max.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
7408 declare i32 @llvm.atomic.load.max.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
7409 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]7410</pre>
7411
7412<pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7413 declare i8 @llvm.atomic.load.min.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
7414 declare i16 @llvm.atomic.load.min.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
Chris Lattner966a3822010-05-05 23:29:09 +0000[diff] [blame]7415 declare i32 @llvm.atomic.load.min.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
7416 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]7417</pre>
7418
7419<pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7420 declare i8 @llvm.atomic.load.umax.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
7421 declare i16 @llvm.atomic.load.umax.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
7422 declare i32 @llvm.atomic.load.umax.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
7423 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]7424</pre>
7425
7426<pre>
Chris Lattner966a3822010-05-05 23:29:09 +0000[diff] [blame]7427 declare i8 @llvm.atomic.load.umin.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7428 declare i16 @llvm.atomic.load.umin.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
Chris Lattner966a3822010-05-05 23:29:09 +0000[diff] [blame]7429 declare i32 @llvm.atomic.load.umin.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
7430 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]7431</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7432
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7433<h5>Overview:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]7434<p>These intrinsics takes the signed or unsigned minimum or maximum of
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7435 <tt>delta</tt> and the value stored in memory at <tt>ptr</tt>. It yields the
7436 original value at <tt>ptr</tt>.</p>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7437
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7438<h5>Arguments:</h5>
7439<p>These intrinsics take two arguments, the first a pointer to an integer value
7440 and the second an integer value. The result is also an integer value. These
7441 integer types can have any bit width, but they must all have the same bit
7442 width. The targets may only lower integer representations they support.</p>
7443
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7444<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7445<p>These intrinsics does a series of operations atomically. They first load the
7446 value stored at <tt>ptr</tt>. They then do the signed or unsigned min or
7447 max <tt>delta</tt> and the value, store the result to <tt>ptr</tt>. They
7448 yield the original value stored at <tt>ptr</tt>.</p>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7449
7450<h5>Examples:</h5>
7451<pre>
Victor Hernandeza70c6df2009-10-26 23:44:29 +0000[diff] [blame]7452%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7453%ptr = bitcast i8* %mallocP to i32*
7454 store i32 7, %ptr
Mon P Wang2c839d42008-07-30 04:36:53 +0000[diff] [blame]7455%result0 = call i32 @llvm.atomic.load.min.i32.p0i32( i32* %ptr, i32 -2 )
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7456 <i>; yields {i32}:result0 = 7</i>
Mon P Wang2c839d42008-07-30 04:36:53 +0000[diff] [blame]7457%result1 = call i32 @llvm.atomic.load.max.i32.p0i32( i32* %ptr, i32 8 )
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7458 <i>; yields {i32}:result1 = -2</i>
Mon P Wang2c839d42008-07-30 04:36:53 +0000[diff] [blame]7459%result2 = call i32 @llvm.atomic.load.umin.i32.p0i32( i32* %ptr, i32 10 )
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7460 <i>; yields {i32}:result2 = 8</i>
Mon P Wang2c839d42008-07-30 04:36:53 +0000[diff] [blame]7461%result3 = call i32 @llvm.atomic.load.umax.i32.p0i32( i32* %ptr, i32 30 )
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7462 <i>; yields {i32}:result3 = 8</i>
7463%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 30</i>
7464</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7465
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7466</div>
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7467
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]7468
7469<!-- ======================================================================= -->
7470<div class="doc_subsection">
7471 <a name="int_memorymarkers">Memory Use Markers</a>
7472</div>
7473
7474<div class="doc_text">
7475
7476<p>This class of intrinsics exists to information about the lifetime of memory
7477 objects and ranges where variables are immutable.</p>
7478
7479</div>
7480
7481<!-- _______________________________________________________________________ -->
7482<div class="doc_subsubsection">
7483 <a name="int_lifetime_start">'<tt>llvm.lifetime.start</tt>' Intrinsic</a>
7484</div>
7485
7486<div class="doc_text">
7487
7488<h5>Syntax:</h5>
7489<pre>
7490 declare void @llvm.lifetime.start(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7491</pre>
7492
7493<h5>Overview:</h5>
7494<p>The '<tt>llvm.lifetime.start</tt>' intrinsic specifies the start of a memory
7495 object's lifetime.</p>
7496
7497<h5>Arguments:</h5>
Nick Lewycky9bc89042009-10-13 07:57:33 +0000[diff] [blame]7498<p>The first argument is a constant integer representing the size of the
7499 object, or -1 if it is variable sized. The second argument is a pointer to
7500 the object.</p>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]7501
7502<h5>Semantics:</h5>
7503<p>This intrinsic indicates that before this point in the code, the value of the
7504 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]7505 never be used and has an undefined value. A load from the pointer that
7506 precedes this intrinsic can be replaced with
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]7507 <tt>'<a href="#undefvalues">undef</a>'</tt>.</p>
7508
7509</div>
7510
7511<!-- _______________________________________________________________________ -->
7512<div class="doc_subsubsection">
7513 <a name="int_lifetime_end">'<tt>llvm.lifetime.end</tt>' Intrinsic</a>
7514</div>
7515
7516<div class="doc_text">
7517
7518<h5>Syntax:</h5>
7519<pre>
7520 declare void @llvm.lifetime.end(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7521</pre>
7522
7523<h5>Overview:</h5>
7524<p>The '<tt>llvm.lifetime.end</tt>' intrinsic specifies the end of a memory
7525 object's lifetime.</p>
7526
7527<h5>Arguments:</h5>
Nick Lewycky9bc89042009-10-13 07:57:33 +0000[diff] [blame]7528<p>The first argument is a constant integer representing the size of the
7529 object, or -1 if it is variable sized. The second argument is a pointer to
7530 the object.</p>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]7531
7532<h5>Semantics:</h5>
7533<p>This intrinsic indicates that after this point in the code, the value of the
7534 memory pointed to by <tt>ptr</tt> is dead. This means that it is known to
7535 never be used and has an undefined value. Any stores into the memory object
7536 following this intrinsic may be removed as dead.
7537
7538</div>
7539
7540<!-- _______________________________________________________________________ -->
7541<div class="doc_subsubsection">
7542 <a name="int_invariant_start">'<tt>llvm.invariant.start</tt>' Intrinsic</a>
7543</div>
7544
7545<div class="doc_text">
7546
7547<h5>Syntax:</h5>
7548<pre>
7549 declare {}* @llvm.invariant.start(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;) readonly
7550</pre>
7551
7552<h5>Overview:</h5>
7553<p>The '<tt>llvm.invariant.start</tt>' intrinsic specifies that the contents of
7554 a memory object will not change.</p>
7555
7556<h5>Arguments:</h5>
Nick Lewycky9bc89042009-10-13 07:57:33 +0000[diff] [blame]7557<p>The first argument is a constant integer representing the size of the
7558 object, or -1 if it is variable sized. The second argument is a pointer to
7559 the object.</p>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]7560
7561<h5>Semantics:</h5>
7562<p>This intrinsic indicates that until an <tt>llvm.invariant.end</tt> that uses
7563 the return value, the referenced memory location is constant and
7564 unchanging.</p>
7565
7566</div>
7567
7568<!-- _______________________________________________________________________ -->
7569<div class="doc_subsubsection">
7570 <a name="int_invariant_end">'<tt>llvm.invariant.end</tt>' Intrinsic</a>
7571</div>
7572
7573<div class="doc_text">
7574
7575<h5>Syntax:</h5>
7576<pre>
7577 declare void @llvm.invariant.end({}* &lt;start&gt;, i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7578</pre>
7579
7580<h5>Overview:</h5>
7581<p>The '<tt>llvm.invariant.end</tt>' intrinsic specifies that the contents of
7582 a memory object are mutable.</p>
7583
7584<h5>Arguments:</h5>
7585<p>The first argument is the matching <tt>llvm.invariant.start</tt> intrinsic.
Nick Lewycky9bc89042009-10-13 07:57:33 +0000[diff] [blame]7586 The second argument is a constant integer representing the size of the
7587 object, or -1 if it is variable sized and the third argument is a pointer
7588 to the object.</p>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]7589
7590<h5>Semantics:</h5>
7591<p>This intrinsic indicates that the memory is mutable again.</p>
7592
7593</div>
7594
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7595<!-- ======================================================================= -->
7596<div class="doc_subsection">
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]7597 <a name="int_general">General Intrinsics</a>
7598</div>
7599
7600<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7601
7602<p>This class of intrinsics is designed to be generic and has no specific
7603 purpose.</p>
7604
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]7605</div>
7606
7607<!-- _______________________________________________________________________ -->
7608<div class="doc_subsubsection">
7609 <a name="int_var_annotation">'<tt>llvm.var.annotation</tt>' Intrinsic</a>
7610</div>
7611
7612<div class="doc_text">
7613
7614<h5>Syntax:</h5>
7615<pre>
Tanya Lattnerbed1d4d2007-06-18 23:42:37 +0000[diff] [blame]7616 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]7617</pre>
7618
7619<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7620<p>The '<tt>llvm.var.annotation</tt>' intrinsic.</p>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]7621
7622<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7623<p>The first argument is a pointer to a value, the second is a pointer to a
7624 global string, the third is a pointer to a global string which is the source
7625 file name, and the last argument is the line number.</p>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]7626
7627<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7628<p>This intrinsic allows annotation of local variables with arbitrary strings.
7629 This can be useful for special purpose optimizations that want to look for
7630 these annotations. These have no other defined use, they are ignored by code
7631 generation and optimization.</p>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]7632
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]7633</div>
7634
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]7635<!-- _______________________________________________________________________ -->
7636<div class="doc_subsubsection">
Tanya Lattner0186a652007-09-21 23:57:59 +0000[diff] [blame]7637 <a name="int_annotation">'<tt>llvm.annotation.*</tt>' Intrinsic</a>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]7638</div>
7639
7640<div class="doc_text">
7641
7642<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7643<p>This is an overloaded intrinsic. You can use '<tt>llvm.annotation</tt>' on
7644 any integer bit width.</p>
7645
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]7646<pre>
Tanya Lattnercf3e26f2007-09-22 00:03:01 +0000[diff] [blame]7647 declare i8 @llvm.annotation.i8(i8 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7648 declare i16 @llvm.annotation.i16(i16 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7649 declare i32 @llvm.annotation.i32(i32 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7650 declare i64 @llvm.annotation.i64(i64 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7651 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]7652</pre>
7653
7654<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7655<p>The '<tt>llvm.annotation</tt>' intrinsic.</p>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]7656
7657<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7658<p>The first argument is an integer value (result of some expression), the
7659 second is a pointer to a global string, the third is a pointer to a global
7660 string which is the source file name, and the last argument is the line
7661 number. It returns the value of the first argument.</p>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]7662
7663<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7664<p>This intrinsic allows annotations to be put on arbitrary expressions with
7665 arbitrary strings. This can be useful for special purpose optimizations that
7666 want to look for these annotations. These have no other defined use, they
7667 are ignored by code generation and optimization.</p>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]7668
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]7669</div>
Jim Laskey2211f492007-03-14 19:31:19 +0000[diff] [blame]7670
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]7671<!-- _______________________________________________________________________ -->
7672<div class="doc_subsubsection">
7673 <a name="int_trap">'<tt>llvm.trap</tt>' Intrinsic</a>
7674</div>
7675
7676<div class="doc_text">
7677
7678<h5>Syntax:</h5>
7679<pre>
7680 declare void @llvm.trap()
7681</pre>
7682
7683<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7684<p>The '<tt>llvm.trap</tt>' intrinsic.</p>
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]7685
7686<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7687<p>None.</p>
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]7688
7689<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7690<p>This intrinsics is lowered to the target dependent trap instruction. If the
7691 target does not have a trap instruction, this intrinsic will be lowered to
7692 the call of the <tt>abort()</tt> function.</p>
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]7693
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]7694</div>
7695
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]7696<!-- _______________________________________________________________________ -->
7697<div class="doc_subsubsection">
Misha Brukman50de2b22008-11-22 23:55:29 +0000[diff] [blame]7698 <a name="int_stackprotector">'<tt>llvm.stackprotector</tt>' Intrinsic</a>
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]7699</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7700
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]7701<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7702
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]7703<h5>Syntax:</h5>
7704<pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7705 declare void @llvm.stackprotector( i8* &lt;guard&gt;, i8** &lt;slot&gt; )
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]7706</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7707
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]7708<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7709<p>The <tt>llvm.stackprotector</tt> intrinsic takes the <tt>guard</tt> and
7710 stores it onto the stack at <tt>slot</tt>. The stack slot is adjusted to
7711 ensure that it is placed on the stack before local variables.</p>
7712
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]7713<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7714<p>The <tt>llvm.stackprotector</tt> intrinsic requires two pointer
7715 arguments. The first argument is the value loaded from the stack
7716 guard <tt>@__stack_chk_guard</tt>. The second variable is an <tt>alloca</tt>
7717 that has enough space to hold the value of the guard.</p>
7718
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]7719<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7720<p>This intrinsic causes the prologue/epilogue inserter to force the position of
7721 the <tt>AllocaInst</tt> stack slot to be before local variables on the
7722 stack. This is to ensure that if a local variable on the stack is
7723 overwritten, it will destroy the value of the guard. When the function exits,
7724 the guard on the stack is checked against the original guard. If they're
7725 different, then the program aborts by calling the <tt>__stack_chk_fail()</tt>
7726 function.</p>
7727
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]7728</div>
7729
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]7730<!-- _______________________________________________________________________ -->
7731<div class="doc_subsubsection">
7732 <a name="int_objectsize">'<tt>llvm.objectsize</tt>' Intrinsic</a>
7733</div>
7734
7735<div class="doc_text">
7736
7737<h5>Syntax:</h5>
7738<pre>
Eric Christopher31e39bd2009-12-23 00:29:49 +0000[diff] [blame]7739 declare i32 @llvm.objectsize.i32( i8* &lt;object&gt;, i1 &lt;type&gt; )
7740 declare i64 @llvm.objectsize.i64( i8* &lt;object&gt;, i1 &lt;type&gt; )
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]7741</pre>
7742
7743<h5>Overview:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]7744<p>The <tt>llvm.objectsize</tt> intrinsic is designed to provide information
Eric Christopher3070e162010-01-08 21:42:39 +0000[diff] [blame]7745 to the optimizers to discover at compile time either a) when an
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]7746 operation like memcpy will either overflow a buffer that corresponds to
7747 an object, or b) to determine that a runtime check for overflow isn't
7748 necessary. An object in this context means an allocation of a
Eric Christopher31e39bd2009-12-23 00:29:49 +0000[diff] [blame]7749 specific class, structure, array, or other object.</p>
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]7750
7751<h5>Arguments:</h5>
7752<p>The <tt>llvm.objectsize</tt> intrinsic takes two arguments. The first
Eric Christopher31e39bd2009-12-23 00:29:49 +0000[diff] [blame]7753 argument is a pointer to or into the <tt>object</tt>. The second argument
7754 is a boolean 0 or 1. This argument determines whether you want the
7755 maximum (0) or minimum (1) bytes remaining. This needs to be a literal 0 or
7756 1, variables are not allowed.</p>
7757
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]7758<h5>Semantics:</h5>
7759<p>The <tt>llvm.objectsize</tt> intrinsic is lowered to either a constant
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]7760 representing the size of the object concerned or <tt>i32/i64 -1 or 0</tt>
7761 (depending on the <tt>type</tt> argument if the size cannot be determined
7762 at compile time.</p>
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]7763
7764</div>
7765
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]7766<!-- *********************************************************************** -->
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]7767<hr>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]7768<address>
7769 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
Misha Brukman86242e12008-12-11 17:34:48 +0000[diff] [blame]7770 src="http://jigsaw.w3.org/css-validator/images/vcss-blue" alt="Valid CSS"></a>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]7771 <a href="http://validator.w3.org/check/referer"><img
Misha Brukman86242e12008-12-11 17:34:48 +0000[diff] [blame]7772 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]7773
7774 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
Reid Spencerca058542006-03-14 05:39:39 +0000[diff] [blame]7775 <a href="http://llvm.org">The LLVM Compiler Infrastructure</a><br>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]7776 Last modified: $Date$
7777</address>
Chris Lattnerb8f816e2008-01-04 04:33:49 +0000[diff] [blame]7778
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]7779</body>
7780</html>